Drive device provided with XY-separating crank mechanism

According to one embodiment, a drive device includes a first piston reciprocatively along a first direction within a first mount plane, a first crankshaft orthogonal to the first mount plane, a first XY separation crank mechanism between the first piston and the first crankshaft, which converts reciprocating motion of the first piston and rotary motion of the first crankshaft into each other, a second piston reciprocatively along a second direction symmetrical to the first direction within a second mount plane symmetrical to the first mount plane about a central reference plane, a second crankshaft orthogonal to the second mount plane, a second XY separation crank mechanism between the second piston and the second crankshaft, which converts reciprocating motion of the second piston and rotary motion of the second crankshaft into each other, and a coupler-synchronizing mechanism which rotates the first and second crankshafts in synchronous with each other.

FIELD

Embodiments described herein relate generally to a driving device comprising an XY separate crank mechanism that transmits reciprocating motion by converting the reciprocating motion into rotational motion or transmits rotational motion by converting the rotational motion into reciprocating motion.

BACKGROUND

A crank mechanism is known as a Mechanism that transmits reciprocating motion by converting the reciprocating motion into rotational motion. For example, engines, compressors and the like include a piston provided reciprocatively inside a cylinder, a coupling rod rotatably connected to the piston, and a crankshaft extending in a direction perpendicular to the direction of reciprocating movement of the piston. The other end of the coupling rod is rotatably connected to a crank pin provided eccentrically with respect to the crankshaft. When the piston reciprocates inside the cylinder, the reciprocating motion is converted into rotational motion of the crankshaft by oscillations of the coupling rod and eccentric rotation of the crankshaft.

In the crank mechanism configured as described above, normally the coupling rod is rotatably connected to the piston via a piston pin and, when power is transmitted, is translated while oscillating about the piston pin. Thus, a force in a rotation direction acts on the piston, causing a frictional loss in a wedge effect shape on a cylinder inner surface at two locations, an outer circumferential portion at a top edge and an outer circumferential portion at a bottom edge of the piston. Normally, smooth reciprocating motion of the piston is enabled by reducing the frictional loss by using a lubricant. However, when a large piston is used, oil may run out, which manifests itself as a sticking phenomenon.

To reduce sticking by such a frictional loss, a driving mechanism provided with a cross head between the piston and coupling rod or using a short piston for a small engine has been proposed.

However, while it is possible to increase the degree of sealing of the piston by providing a cross head, a frictional loss changing every 180° is caused by a wedge effect at two locations also in the cross head. Thus, while a reciprocating motion is produced as a motion, a loss is caused by vibration derived from the reciprocating motion.

DETAILED DESCRIPTION

Various embodiments will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment, a drive device includes a first cylinder in a first mount plane located on one side of a central reference plane, a first piston in the first cylinder reciprocatively along a first direction within the first mount plane, a first crankshaft extending orthogonal to the first mount plane, a first XY separation crank mechanism between the first piston and the first crankshaft within the first mount plane, which converts reciprocating motion of the first piston and rotary motion of the first crankshaft into each other, a second cylinder in a second mount plane located on an opposite side of the central reference plane and located in the second mount plane symmetrical to the first mount plane with regard to the central reference plane, a second piston in the second cylinder reciprocatively along a second direction symmetrical to the first direction within the second mount plane, a second crankshaft extending orthogonal to the second mount plane,

a second XY separation crank mechanism between the second piston and the second crankshaft within the second mount plane, which converts reciprocating motion of the second piston and rotary motion of the second crankshaft into each other, and

a coupler-synchronizing mechanism which couples the first crankshaft and the second crankshaft with each other and rotates the first crankshaft and the second crankshaft in synchronous with each other.

The first XY separation crank mechanism comprises a first support member provided reciprocatively along in the first direction, a first crank connection member mounted to the first support member reciprocatively along the third direction orthogonal to the first direction within the first mount plane, to which a crankpin of the first crankshaft is engaged rotatably, a first coupling member which couples the first piston and the first support member with each other and a third coupling member which couples the third piston and the first support member with each other, and

the second XY separation crank mechanism comprises a second support member provided reciprocatively along the second direction; a second crank connection member mounted to the second support member reciprocatively along the fourth direction orthogonally to the second direction within the second mount plane, to which a crankpin of the second crankshaft is engaged rotatably, a second coupling member which couples the second piston and the second support member and a fourth coupling member which couples the second piston and the fourth support member.

Z-mechanism XY separate crank mechanisms according to embodiments and various driving apparatus provided therewith will be described with reference to the drawings. Structures common in embodiments are denoted by the same reference numbers or symbols. Overlapping explanations are omitted. Each figure is an exemplary diagram of an embodiment to prompt understanding of the embodiment. The shapes, dimensions or ratios in the drawings may differ from those of the actual device. However, they may be appropriately changed in consideration of the explanation below and known art.

First Embodiment

FIG. 1is a perspective diagram showing a drive device according to the first embodiment andFIG. 2is an exploded perspective diagram showing a first drive unit of the drive device.

In this embodiment, the drive device is constituted as, for example, an engine or a compressor. As shown inFIG. 1, a drive device10comprises a first drive unit20aincluding a first crankshaft12a, a second drive unit20bincluding a second crankshaft12band a coupler-synchronizing mechanism50which couples the first crankshaft12aand the second crankshaft12bwith each other and synchronously rotates them.

The first drive unit20aand the second drive unit20bhave the same structure. The first drive unit20aand the second drive unit20bare arranged on the respective sides of a central reference plane CRP and further the first drive unit20aand the second drive unit20bare arranged to be symmetrical with respect to the central reference plane CRP in terms of lateral and longitudinal directions (mirror arrangement).

In this embodiment, the first drive unit20acomprises a first cylinder22alocated on one side of the central reference plane CRP and provided on a first mount plane MP1which intersects orthogonally with the central reference plane CRP, a first piston24aprovided in the first cylinder22ato be reciprocative along a first direction within the first mount plane MP1, the first crankshaft12aextending orthogonal to the first mount plane MP1and a first XY separate crank mechanism30aprovided between the first piston24aand the extending first crankshaft12aand within the first mount plane MP1, which converts reciprocating motion of the first piston24ato rotational motion of the first crankshaft12aand vice versa. A piston with a circular cross section is used for the first piston24a.

In this embodiment, the first direction, which is the reciprocating direction of the first piston24a, is defined as a first direction X1orthogonal to the central reference plane CRP. The first crankshaft12ais disposed substantially parallel to the central reference plane CRP.

The second drive unit20bcomprises a second cylinder22blocated on an opposite side of the central reference plane CRP and provided on a second mount plane MP2intersecting orthogonally to the central reference plane CRP, the second piston24bprovided in the second cylinder22bto be reciprocatively in a second direction within the second mount plane MP2, a second crankshaft12bextending orthogonal to the second mount plane MP2and a second XY separate crank mechanism30bprovided between the second piston24band the second crankshaft12band within the second mount plane MP2, which converts reciprocating motion of the second piston24bto rotational motion of the second crankshaft12band vice versa. A piston with a circular cross section is used for the second piston24b.

The second mount plane MP2is located symmetrical with the first mount plane MP1with respect to the central reference plane CRP. The second direction which is the direction of reciprocation motion of the second piston24ais symmetrical with the first direction X1mentioned above, and is defined as a second direction X2orthogonal to the central reference plane CRP. The first direction X1and the second direction X2make an angle of 180 degrees, that is, they are along the same direction. The first piston24aand the second piston24bare arranged to be coaxial.

As shown inFIGS. 1 and 2, the first crankshaft12aof the first drive unit20ais supported rotatably with a bearing (not shown) by both axial ends of the shaft. One set of crank webs14aare fixed to a halfway portion of the first crankshaft12a, and a crankpin16ais fixed between the crank webs14a. The central axis of the crankpin16ais located to be parallel and also eccentrically with respect to the first crankshaft12a. The crankpin16aeccentrically rotates around the first crankshaft12aaccording to the rotation of the first crankshaft12a.

A first XY separate crank mechanism30ais provided between the first piston24aand the first crankshaft12aand configured to convert the reciprocating motion of the first piston24aalong the first direction X1and the rotary motion of the first crankshaft12ato each other to be transmitted.

The first XY separate crank mechanism30acomprises, in the first mount plane MP1including the central axis of the first piston24a(the moving shaft or the X-axis), a first support member (L-shaped combinatory member)32aprovided reciprocatively along the first direction X1, a first crank connection member (crank connection plate)34aattached to the first support member32aso as to be reciprocative along the third direction Y1(Y-axis direction) orthogonal to the first direction X1in the first mount plane MP1, and a first coupling rod36aas a coupling member which couples the first piston24aand the first support member32a. The movable central axis (the first direction X1) of the first support member32a, the movable central axis (the third direction Y1) of the first crank connection member34a, and the movable central axis (the first direction X1) of the first coupling rod36aare located in the first mount plane MP1.

The first support member32ais formed into, for example, an L shape and comprises a first support portion33aextending along the first direction X1and a second support portion33bextending along the third direction Y1from one end (a left end, here) of the first support portion33a, as an integrated member. A first linear slider40ais fixed to the first support portion33a. Further, a guide rail44ais installed in an inner surface of the housing (not shown) so as to extend along the first direction X1within the first mount plane MP1. The first linear slider40ais supported and guided reciprocatively by the guide rail44a. Thus, of the first support members32a, only the first support portion33ais supported reciprocatively on the guide rail44aalong the first direction X1.

A guide rail44bextending along the third direction Y1is fixed to the second support portion33bof the first support member32aor is formed to be integrated with the second support portion. A second linear slider41ais mounted to the first crank connection member34aso as to extend along the third direction Y1. The second linear slider41ais supported and guided reciprocatively by the guide rail45a. Thus, only one end of the first crank connection member34ais supported by the first support member32areciprocatively along the third direction Y1.

The first and the second linear sliders40aand41amay comprise ball bearings build therein, which rollably contact the guide rails44aand45a, respectively.

The first crank connection member34ais formed into, for example, a circular block shape, and comprises a through-hole46having a circular cross section. The first crank connection member34ais formed to be dividable into a first half portion51aand a second half portion51bnu a dividing surface53containing a center of the through-hole46, and the second half portion51bis fixed to the first half portion51awith a screw or the like. The second linear slider41adescribed above is fixed to a flat portion of the first half portion51a.

The crankpin16aof the first crankshaft12ais rotatably penetrated through the through-hole46of the first crank connection member34avia a bearing such as a ball bearing or a plain bearing. Thus, the first crank connection member34ais engaged with the first crankshaft12ato connect the first crankshaft12aand the first support member32atogether.

The connection member includes the first coupling rod36a. An axial end of the first coupling rod36ais coupled with the first piston24avia a support pin and the other axial end is coupled with the second support portion33bof the first support member32a. The first coupling rod36aextends along the first direction X1and is coaxial with a moving shaft of the first piston24a. The first coupling rod36areciprocates along the first direction X1together with the first support member32aas one unit to reciprocally move the first piston24aalong the first direction X1.

As shown inFIG. 1, the second crankshaft12band the second XY separate crank mechanism30bof the second drive unit20bhave the identical structures as those of the first crankshaft12aof and the first XY separate crank mechanism30aof the first drive unit20a, respectively. The second crankshaft12band the second XY separate crank mechanism30bare symmetrical with the first crankshaft12aand the first XY separate crank mechanism30awith respective to the central reference plane CRP.

In detail, the second crankshaft12bis rotatably supported with bearings (not shown) by both axial ends, and is arranged substantially parallel to the first crankshaft12a. One set of crank webs14bare fixed to the halfway portion of the second crankshaft12b, and the crankpin16b(seeFIG. 3) is fixed between these crank webs14b. The crankpin16beccentrically rotates around the second crankshaft12baccording to the rotation of the second crankshaft12b.

The second XY separate crank mechanism30bcomprises, in the second mount plane MP2including the central axis of the second piston24b(the moving shaft or the X-axis), a second support member (L-shaped combinatory member)32bprovided reciprocatively along the second direction X2, a second crank connection member (crank connection plate)34battached to the second support member32bso as to be reciprocative along the fourth direction Y2(Y-axis direction) orthogonal to the second direction X2in the second mount plane MP2, and a second coupling rod36bas a coupling member which couples the second piston24band the second support member32b. The movable central axis (the second direction X2) of the second support member32b, the movable central axis (the fourth direction Y2) of the second crank connection member34b, and the movable central axis (the second direction X2) of the second coupling rod36bare located in the second mount plane MP2.

The second support member32bis formed into, for example, an L shape and comprises a first support portion35aextending along the second direction X2and a second support portion35bextending along the fourth direction Y2from one end (a right end, here) of the first support portion35a, as an integrated member. The first support portion35ais fixed to a first linear slider40a, which is reciprocatively supported and guided by a guide rail45aalong the second direction X2. Thus, of the second support members32b, only the first support portion35ais supported reciprocatively on the guide rail45aalong the second direction X2. In this embodiment, the guide rail45ais formed from a common guide rail used also for the guide rail44aof the first drive unit20a. The guide rail45amay be divided from the guide rail44aat a position of the central reference plane CRP.

A guide rail45bextending along the fourth direction Y2is fixed to the second support portion35bof the second support member32b, or it is formed integrally with second support portion as one unit. A second linear slider41bis attached to the second crank connection member34bto extend along the fourth direction Y2. The second linear slider41bis reciprocatively supported and guided by the guide rail45b. Thus, only one end portion of the second crank connection member34bis reciprocatively supported by the second support member32balong the fourth direction Y2.

The second crank connection member34bcomprises a through-hole with a circular cross section, in which the crankpin16bof the second crankshaft12bis penetrated rotatably via a bearing such as a ball bearing or a plain bearing. Thus, the second crank connection member34bis engaged with the second crankshaft12bto connect the second crankshaft12band the second support member32btogether.

The axial end of the second coupling rod36bis connected with the second piston24bvia a support pin, and the other axial end is connected with the second support portion35bof the second support member32b. The second coupling rod36bextends along the second direction X2and is provided coaxially with the moving shaft of the second piston24b. The second coupling rod36breciprocates together with the second support member32bas one unit along the second direction X2to reciprocally move the second piston24balong with the second direction X2.

As shown inFIGS. 1 and 2, a coupler-synchronizing mechanism50of the drive device10comprises a first gear52aattached coaxially to one end portion of the first crankshaft12aand a second gear52battached coaxially to one end portion of the second crankshaft12b. The first gear52aand the second gear52bare formed to have the same diameter and the same number of teeth and to be engaged with each other. The first crankshaft12aand the second crankshaft12bare coupled with each other via the first gear52aand the second gear52b. As the first gear52arotates, the second gear52brotates synchronously with the rotation of the first gear52ain a direction reverse to that of the first gear52a. Thus, the first crankshaft12aand the second crankshaft12brotate synchronously in opposite directions.

The first drive unit20aand the second drive unit20bare arranged to be symmetrical laterally and longitudinally with respect to the central reference plane CRP, and therefore they operate symmetrically. As shown inFIG. 3, when the first piston24amoves to a top dead center, the second piston24bsynchronously also moves to a top dead center. As shown inFIG. 4, when the first piston24amoves toward a bottom dead center from the top dead center, the second piston24bmoves simultaneously from the top dead center toward a bottom dead center. As shown inFIGS. 3 and 4, the first XY separate crank mechanism30aand second XY separate crank mechanism30balso operate synchronously with each other while maintaining the symmetrical state with respect to the central reference plane CRP.

When the drive device10configured as above is used as an engine, a suction valve and an exhaust valve are provided for a cylinder head of the first cylinder22aand a cylinder head of the second cylinder22bto introduce fuel and air into the first cylinder22aand the second cylinder22b, which are compressed with the first piston24aand the second, piston24b, and the fuel is combusted. Thereby, driving force is applied to the first piston24aand the second piston24b, and the first piston24aand the second piston24breciprocate along the first direction X1and the second direction X2, respectively. The reciprocating motion of the first piston24ais converted into rotary motion by the reciprocating motion of the first support member32aalong the first direction X1and the reciprocating motion of the first crank connection member34aalong the third direction Y1in the first XY separate crank mechanism30a, and transmitted to the first crankshaft12a. Thereby, rotation output is applied to the first crankshaft12a.

Simultaneously, the reciprocating motion of the second piston24bis converted into rotary motion by the reciprocating motion of the second support member32balong the second direction X2and the reciprocating motion of the second crank connection member34balong the fourth direction Y2in the second XY separate crank mechanism30b, and transmitted to the second crankshaft12b. Thereby, rotation output is applied to the second crankshaft12b.

When the drive device10is used as a compressor, rotational force is applied at least one of the first crankshaft12aand the second crankshaft12bby a motor or the like. Thereby, the first crankshaft12aand the second crankshaft12brotate in opposite directions to each other, and the crankpin of each crankshaft eccentrically rotate therearound. The eccentric rotary motion of the crankpin16aof the first crankshaft12ais separated into the reciprocating motion along the third direction Y1and the reciprocating motion along the first direction X1by the first crank connection member34aand the first support member32aof the first XY separate crank mechanism30a, and the reciprocating motion of the first support member32aalong the first direction X1is transmitted to the first piston24avia the first connection member36a. Thereby, the first piston24areciprocates in the first cylinder22aalong the first direction X1to compress the fluid in the first cylinder22aand then output it from the cylinder head.

Similarly, the eccentric rotary motion of the crankpin16bof the second crankshaft12bis separated into the reciprocating motion along the fourth direction Y2and the reciprocating motion along the second direction X2by the second crank connection member34band the second support member32bof the second XY separate crank mechanism30b, and the reciprocating motion of the second support member32balong the second direction X2is transmitted to the second piston24bvia the second connection member36b. Thus, the second piston24breciprocates in the second cylinder22balong the second direction X2to compress the fluid in the second cylinder22band output it from the cylinder head.

With the drive device10configured as above, the first drive unit20aand the second drive unit20brespectively include the first and second XY separate crank mechanisms30aand30bwhich can separate and convert the rotary motion of the first crankshaft12aand the rotary motion of the second crankshaft12binto linear reciprocating motion along the first direction and linear reciprocating motion along the third and fourth directions orthogonal to the first direction and second direction, respectively, thereby making it possible to realize perfect parallel motion of the first piston24aand the second piston24b. Therefore, uneven contact of the piston to the cylinder can be avoided, and the sealing property can be improved, the friction loss can be reduced, and side thrust lossless can be achieved. Thus, a high efficiency can be achieved. Further, since the first drive unit and the second drive unit are arranged and configured to be symmetrical along left to right directions as well as front to rear directions (mirror arrangement) with respect to the central reference plane, vibration caused by deviation can be completely canceled out, thereby making it possible to form a non-vibrating rotary structure.

As to conventional engines, vibration decreases slowly as the number of cylinders increases as 6 cylinders, 8 cylinders, and 12 cylinders. In contrast, when an engine is configured using the drive unit according to this embodiment, the engine can balance completely only by two cylinders and can realize far less vibration than the conventional multi-cylinder engine with three or more cylinders. Thus, ultimately, a three or more-cylinder engine can be compacted to 2 cylinders of extremely low vibration amplitude, thereby making it possible to realize significant downsizing of the engine, reduction of the weight, and less valves.

Further, when the drive device10is used as an engine, reverse rotary outputs equal to and reversed from each other, can be obtained from the first crankshaft and the second crankshaft, that is, synchronous identical reverse rotation two-shaft outputs can be obtained. The synchronous identical reverse rotation two-shaft outputs can produce stable thrust without unsteadiness, which can drive, for example, the blades of helicopters or the screws of marine vessels. Furthermore, the drive device10can also be used for the engines of airplanes. The first pistons and the second piston move simultaneously in directions opposite to each other, and therefore even when the drive device10is applied not only to an engine but to a compressor or a pump, non-vibrating operation can be achieved.

Moreover, with the XY separate crank mechanism, the side thrust of the pistons can be avoided, and therefore the cylinders and pistons can be formed from a ceramic, glass or the like, thereby making it possible to structure a heat-insulating engine with sufficient thermal efficiency at low temperature. Further, in the drive unit, no vibration caused by side thrust is produced; therefore the cylinder can be formed from carbon fiber, or a plastic raw material such as PBT. Thus, an ultralight engine, which is ⅕ to 1/10 of the conventional engines, can be manufactured.

As described above, according to the first embodiment, the friction loss and vibration can be reduced and thus a drive unit with high operation efficiency can be obtained.

FIG. 26is a diagram showing comparison between a formula for displacement of a slider crank mechanism (Type 1) provided with a conventional coupling rod and a formula for displacement of the XY separate crank mechanism (Z-mechanism Type 2) according to this embodiment.FIG. 27showing a formula of kinetic analysis of the XY separate crank mechanism according to this embodiment.FIG. 28shows a kinetic analysis of the above-described conventional slider crank mechanism.FIG. 29shows comparison in result of analysis of vibration between the conventional slider crank mechanism (Type 1) and the XY separate crank mechanism (Type 2) according to this embodiment.

As shown inFIG. 26, in the conventional slider crank mechanism, the formula of the stroke includes square terms and square-root terms, and if the stroke is differentiated by time dt, the circulation and diversion occur, and therefore it is understood that vibration cannot be avoided. By contrast, in the XY separate crank mechanism according to this embodiment, S1and S2are linear expressions, and even if differentiated by dt, they are not diverged. Therefore, with mirror arrangement of the first drive unit and the second drive unit, each including the XY separate crank mechanism, it can be understood that the vibration can be avoided.

As shown inFIGS. 27 to 29, as expressed by the formulas (3) and (4) for the kinetic analysis of the conventional slider crank mechanism, the slider crank mechanism generates phase deviation due to rotation number and therefore it becomes difficult to stop the vibration by one term. As enclosed by an ellipse A shown inFIG. 29, the slider crank mechanism changes its loss significantly for each angle. By contrast, as indicated by the formulas (1) and (2) of the kinetic analysis of the XY separate crank mechanism, the XY separate crank mechanism takes linear expressions of only -mg; therefore vibration can be easily cancelled out by placing the first drive unit and the second drive unit in mirror arrangement. As enclosed by an ellipse B shown inFIG. 29, the XY separate crank mechanism does not have substantial loss since the weight of the mechanism itself is the only formed applied thereto.

Next, drive devices according to other embodiments will be described. Note that in other embodiments described below, the same member as those the first embodiment described above will be denoted by the same reference symbols, and the detailed explanations therefor will be omitted. Structures different from those of the first embodiment will be mainly described in detail.

Second Embodiment

FIG. 5is a perspective view showing a drive device according to the second embodiment. According to the second embodiment, pistons having different plan and cross-sectional shapes, i.e., an un-circular shape are used as a first piston24aand a second piston24b. In this embodiment, the first piston24aand the second piston24bare formed into an oval shape such as an elliptical or field-track shape, and each have a long axis L and a short axis S orthogonal to the long shaft L. A first cylinder22aand a second cylinder22bformed into a shape having an oval cross section, to correspond to the first piston24aand the second piston24b, respectively.

The long axis L of the first piston24ais located within a first mount plane to be parallel to a second support portion33bof a first support member32a, that is, parallel to the third direction Y1. The long axis L of the second piston24bis located within a second mount plane to be parallel to a second support portion35bof a second support member32b, that is, parallel to the fourth direction Y2.

In the drive device10, the other structure is the same as that of the drive unit according to the first embodiment.

When using the first and second pistons24aand24bhaving an oval shape, the displacement of the piston can be increased to two to three times as compared to a circular piston having diameter equal to the short axis S of these pistons. Moreover, the piston area can be increased for the same stroke, and therefore the volume can be increased. By using oval pistons in place of circular pistons, the capacity can be increased 2.5 times, for example. Thus, for a 2000-cc two-cylinder engine, the weight can be reduced to about ¼ of the conventional 4-cylinder engine with circular pistons, making it possible to reduce the weight and downsize.

Moreover, in the drive device10, the first piston24aand the second piston24bcan be driven in perfect parallel motion. Therefore, even when using non-circular, for example, oval pistons, or using large-sized pistons, the uneven contact of the pistons can be avoided, thereby achieving a sealing property and a high efficiency in side thrust lossless.

Furthermore, an advantageous effect similar to that of the first embodiment can be obtained by the drive device10of the second embodiment. In the second embodiment, the shape of the pistons is not limited to the oval shape, but it may as well be other non-circular shapes, for example, a rectangular shape with rounded corners, or other polygonal shape, or elliptical shape with a narrowed central portion.

Third Embodiment

FIG. 6is a perspective view showing a drive device according to the third embodiment. The third embodiment is different from the first embodiment in the structure of the coupler-synchronizing mechanism. As shown inFIG. 6, a coupler-synchronizing mechanism50comprise a first drive pulley54acoaxially mounted to one end portion of a first crankshaft12a, a second drive pulley54bcoaxially mounted to one end portion of a second crankshaft12b, a plurality of tension pulleys56a,56band56ceach comprising a rotary shaft parallel to the rotary shafts of these drive pulleys, and an endless toothed belt58looped over the first and second drive pulleys and the tension pulleys.

The first crankshaft12aand the second crankshaft12bare coupled with each other via the coupler-synchronizing mechanism50, and rotate synchronously in opposite directions. More specifically, when the first drive pulley54arotates with the first crankshaft12a, the rotation of the first drive pulley54ais transmitted to the second drive pulley54bby the toothed belt58, and the second drive pulley54brotates in an opposite direction together with the second crankshaft12b. Thus, the first crankshaft12aand the second crankshaft12brotate synchronously in opposite directions.

In the third embodiment also, pistons having different plane and cross section shapes, i.e., un-circular shapes, for example, oval pistons are used as the first piston24aand the second piston24b.

The other structure of the drive device10of the third embodiment is the same as that of the first or second embodiment. An advantageous effect similar to that of the first embodiment can be obtained by the drive device10of the third embodiment. In the third embodiment, the coupler-synchronizing mechanism50is not limited to the combination of pulleys and a belt, but may be a combination of a sprocket and a chain.

Fourth Embodiment

FIG. 7is a perspective view showing a drive device according to the fourth embodiment. A drive device10of the fourth embodiment is formed as of a multiple cylinder type, for example, a 4-cylinder drive device. More specifically, the drive device10comprises, in addition to the first drive unit20aand the second drive unit20bdescribed above, a third drive unit20cand a fourth drive unit20d. The third drive unit20chas the same structure as that of the first drive unit20aand is arranged along a direction parallel to the first drive unit20aand the central reference plane CRP. The fourth drive unit20dhas the same structure as that of the second drive unit20b, and is arranged along a direction parallel to the second drive unit20band the central reference plane CRP.

The third drive unit20cand the fourth drive unit20dhave the same structure. The third drive unit20cand the fourth drive unit20dare arranged on both sides of the central reference plane CRP, respectively, and are arranged and configured to be symmetrical along left to right directions as well as front to rear directions (mirror arrangement) with respect to the central reference plane CRP.

The third drive unit20ccomprises a third cylinder22clocated on one side of the central reference plane CRP and provided on a third mount plane MP3orthogonal to the central reference plane CRP, a third piston24cprovided in the third cylinder22cto be reciprocative along the first direction X1within the third mount plane MP3, a first crankshaft12aextending orthogonal to the third mount plane MP3, and a third XY separate crank mechanism30cprovided between the third piston24cand the first crankshaft12awithin the third mount plane MP3, which converts the reciprocating motion of the third piston24aand the rotary motion of the first crankshaft12ainto each other. The third mount plane MP3opposes to be parallel to the first mount plane MP1of the first drive unit20a. The first direction which is the reciprocation direction of the third piston24cis defined as a first direction X1orthogonal to the central reference plane CRP. Further, the first crankshaft12ais coupled with the first crankshaft12aof the first drive unit20aor formed integrally as one body, and they extend coaxially.

The fourth drive unit20dcomprises a fourth cylinder22dlocated on an opposite side of the central reference plane CRP and provided on a fourth mount plane MP4orthogonal to the central reference plane CRP, a fourth piston24dprovided in the fourth cylinder22dto be reciprocative along the second direction X2within the fourth mount plane MP4, a second crankshaft12bextending orthogonal to the fourth mount plane MP4, and a fourth XY separate crank mechanism30dprovided between the fourth piston24dand the second crankshaft12b, which converts the reciprocating motion of the fourth piston24dand the rotary motion of the second crankshaft12binto each other.

The fourth mount plane MP4is located symmetrical to the third mount plane MP3with regard to the central reference plane CRP. Further, the fourth mount plane MP4opposes parallel to the second mount plane MP2of the second drive unit20b. The second direction which is a reciprocation direction of the fourth piston24dis a direction symmetrical to the first direction X1described above and is defined as a second direction X2orthogonal to the central reference plane CRP. The first direction X1and the second direction X2make an angle of 180 degrees with respect to each other, that is, they are in the same direction and the third piston24cand fourth piston24dare arranged to be coaxial with each other. Further, the second crankshaft12bof the fourth drive unit20dis coupled with the second crankshaft12bof the second drive unit20b, or formed integrally in one unit, and they extend coaxially.

The third XY separate crank mechanism30ccomprises a third support member (L-type combinatory)32cprovided reciprocatively along the first direction X1, a third crank connection member (crank connection plate)34cmounted reciprocatively to the third support member32calong the third direction Y1(Y-axial direction) orthogonal the first direction X1in the third mount plane MP3and engaged rotatably with the crankpin of the first crankshaft12a, and a coupling rod36cwhich connects the third piston24cand the third support member32cto each other.

The third support member32cis formed into an L shape, and comprises a first support portion extending in the first direction X1and a second support portion extending in the third direction Y1from one end (here, left end) of the first support portion as one unit. Of the third support members32c, only the first support portion is supported reciprocatively on a guide rail44aalong the first direction X1via a first linear slider, and only one end portion of the third crank connection member34cis supported reciprocatively by the third support member32calong the third direction Y1.

The fourth XY separate crank mechanism30dof the fourth drive unit20dhas the same structure as that of the third XY separate crank mechanism30c, and is arranged to be symmetrical to the third XY separate crank mechanism30cwith regard to the central reference plane CRP. More specifically, the fourth XY separate crank mechanism30dcomprises a fourth support members (L-type combinator)32dprovided reciprocatively along the second direction X2, a fourth crank connection member (crank connection plate)34dmounted reciprocatively along a fourth direction Y2(Y-axial direction) orthogonal to the second direction X2in a fourth mount plane MP4and engaged rotatably with the crankpin of the second crankshaft12b, and a coupling rod36dwhich connects the fourth piston24dand the fourth support member32dto each other.

In the fourth embodiment, pistons having different plane and cross section shapes, i.e., un-circular shapes, for example, oval pistons having, for example, a long axis L and a short axis S, are used as the first, second, third and fourth pistons24a,24b,24cand24d. The first piston24ais arranged so that the long axis L is parallel to the third direction Y1and the second piston24bis arranged so that the long axis L is parallel to the fourth direction Y2. Similarly, the third piston24cis arranged so that the long axis L is parallel to the third direction Y1, and the second piston24bis arranged so that the long axis L is parallel to the fourth direction Y2. Thus, the long axis L of the third piston24cis arranged parallel to the long axis L of the first piston24a, and the long axis L of the fourth piston24dis arranged parallel to the long axis L of the second piston24b.

In the fourth embodiment, the other structure of the drive device10is the same as that of the drive device according to the first or second embodiment. An advantageous effect similar to that of the first embodiment can be obtained by the drive device10of the fourth embodiment. Further, the drive device10can be easily modeled into a multiple cylinder type. According to this embodiment, the so-called horizontally opposed type 4-cylinder engine or compressor can be provided. Further, when a plurality of oval-shaped pistons are arranged so that the long axes of the piston are arranged to be parallel to each other, the pistons can be arranged close to each other along the axial direction of the crankshaft. Thus, even if the drive device is formed into a multiple cylinder type, the dimensions of the drive device along the axial direction of the crankshaft can be reduced, thereby making it possible to downsize the drive device.

In the fourth embodiment, the drive device is not limited to the 4-cylinder type, but may be 6-cylinder or 8-cylinder type or more. Moreover, the shape of the pistons of each drive unit is not limited to an oval shape, but may be some other different shape or a circular.

Fifth Embodiment

FIG. 8is a side view showing a drive device according to the fifth embodiment. The first to fourth embodiments described above are directed to the so-called horizontally opposite type drive device, in which the first direction which is the moving direction of the first piston and the second direction which is the moving direction of the second piston are opposite to each other by 180 degrees, that is, they extend coaxially. By contrast, according to the fifth embodiment, the drive device10comprise a first drive unit20aand a second drive unit20barranged on both sides of the central reference plane CRP, respectively, and the first drive unit20aand the second drive unit20bare arranged so that the first direction X1which is the moving direction of the first piston24aand the second direction X2which is the move direction of the second piston24bmake an angle θ, which is less than 180 degrees, for example, 60 to 90 degrees.

The first drive unit20aand the second drive unit20bare the same as the first drive unit and the second drive unit in the first embodiment, respectively. But, in the fifth embodiment, the first piston24aand the second piston24bare oval pistons.

The first drive unit20ais located on one side of the central reference plane CRP and provided on the first mount plane MP1orthogonal to the central reference plane CRP. The first piston24ais provided in the first cylinder22ato be reciprocative along the first direction X1within the first mount plane MP1. In this embodiment, the first direction X1is defined as a direction which crosses the central reference plane CRP at an angle less than 90 degrees. The first crankshaft12ais arranged substantially parallel to the central reference plane CRP. The first piston24ais arranged at such a direction that the long axis L thereof orthogonally crosses the first direction X1within the first mount plane MP1.

The second drive unit20bis located on a side opposite to the central reference plane CRP and is formed on the second mount plane MP2orthogonal to the central reference plane CRP. The second mount plane MP2is located to be symmetrical to the first mount plane MP1with regard to the central reference plane CRP. Thus, the second drive unit20bis arranged to be symmetrical to the first drive unit20awith regard to the central reference plane CRP (mirror arrangement). The second direction X2which is the reciprocating direction of the second piston24bis symmetrical to the first direction X1of the first piston24a, and is defined to cross the central reference plane CRP at an angle less than 90 degrees. The first direction X1and the second direction X2cross each other at the central reference plane CRP to make an angle θ less than 180 degrees, for example, 50 to 120 degrees. Note that the second piston24bis arranged along such a direction that the long axis L thereof orthogonally crosses the second direction X2within the second mount plane MP2.

When the first direction X1and the second direction X2make an angle θ of 10 to 170 degrees, balance-adjusting notches15aand15bare formed in a crank web core14aof the first crankshaft12aand a crank web core14bof the second crankshaft12b, respectively, to maintain the rotation balance between the first and the second crankshafts12aand12b.

The other structure of the drive device10is the same as that of the drive device according to the first embodiment.

As described above, with the drive device10of the fourth embodiment, the so-called V type engine can be configured. Note that an advantageous effect similar to that of the first embodiment can be obtained by the drive device10of the fifth embodiment.

Sixth Embodiment

FIG. 9is a side view showing a drive device according to the sixth embodiment. A drive device10of this embodiment is configured substantially identically to the drive device10the fifth embodiment described above. In the sixth embodiment, pistons having circular plane and cross-section are used as a first piston24aand a second piston24b.

In a first drive unit20a, a first support member32aof a first XY separate crank mechanism30ais provided in an opposite direction to that of the first support member in the embodiment described above. More specifically, a first support portion33aof the first support member32aand a guide rail44aare arranged on a side of the central reference plane CRP with regard to the first crankshaft12ain the first mount plane MP1, and extend parallel to the first direction X1. A second support portion33bof the first support member32aextends in the third direction Y1from one end of the first support portion33a, so as to be orthogonal to the moving shaft (the first direction X1) of the first piston24a.

In the second drive unit20barranged and configured to be symmetrical to the first drive unit20a, the first support portion35aand the guide rail45aof the second XY separate crank mechanism30bare arranged on a side the central reference plane CRP with regard to the second crankshaft12bin the second mount plane MP2, so as to extend parallel to the second direction X2. The second support portion35bof the second support member32bextends in the fourth direction Y2from one end of the second support portion33b, so as to be orthogonal to the moving shaft (the second direction X2) of the second piston24b.

The first direction X1which is the moving direction of the first piston24aand the second direction X2which is the moving direction of the second piston24bcross each other at the central reference plane CRP to make an angle θ less than 180 degrees, for example, 60 to 90 degrees.

In the sixth embodiment configured as described above, the so-called V type drive device10can be configured. Note that an advantageous effect similar to that of the first embodiment can be obtained also by the drive device10of the sixth embodiment.

Seventh Embodiment

FIG. 10is a side view showing a drive device according to the seventh embodiment. According to this embodiment, a first drive unit20aand a second drive unit20bof a drive device10are symmetrically arranged so that the first direction X1which is the moving direction of a first piston24aand the second direction X2which is the moving direction of a second piston24bare parallel to each other and they are parallel to the central reference plane CRP. Thus, a first support portion35aand a guide rail45aof the first XY separate crank mechanism30aand a first support portion33aand a guide rail44aof the second XY separate crank mechanism30bare parallel to each other, and also parallel to the central reference plane CRP. The other structure of the drive device10is the same as that of the drive device of the fifth embodiment shown inFIG. 8.

Eighth Embodiment

FIG. 11is a side view showing a drive device according to the eighth embodiment. According to this embodiment, as in the case of the seventh embodiment described above, a first drive unit20aand a second drive unit20bof a drive device10are symmetrically arranged so that the first direction X1which is the moving direction of a first piston24aand the second direction X2which is the moving direction of a second piston24bare parallel to each other, and also they are parallel to the central reference plane CRP.

In the first drive unit20a, a first support member32aof the first XY separate crank mechanism30ais provided in an opposite direction to that of the first support member the embodiment described above. More specifically, a first support portion33aof the first support member32aand a guide rail44aare arranged on a side of the central reference plane CRP with regard to the first crankshaft12ain the first mount plane MP1, and extend parallel to the first direction X1. A second support portion33bof the first support member32aextends in the third direction Y1from one end of the first support portion33a, so as to be orthogonal to the moving shaft (the first direction X1) of the first piston24a.

In the second drive unit20b, a first support portion35aand a guide rail45aof the second XY separate crank mechanism30barranged on a side of the central reference plane CRP with regard to the second crankshaft12bin the second mount plane MP2, and extend parallel to the second direction X2. A second support portion35bof the second support member32bextends in the fourth direction Y2from one end of the second support portion33b, so as to be orthogonal to the moving shaft (the second direction X2) of the second piston24b. The other structure of the drive device10is the same as that of the seventh embodiment.

Ninth Embodiment

FIG. 12is a side view showing a drive device according to the ninth embodiment. According to this embodiment, as in the case of the seventh embodiment described above, a first drive unit20aand a second drive unit20bof a drive device10are symmetrically arranged so that the first direction X1which is the moving direction of a first piston24aand the second direction X2which is the moving direction of a second piston24bare parallel to each other and also parallel to the central reference plane CRP. In this embodiment, pistons having circular plane and cross-section are used as the first piston24aand the second piston24b. The other structure of the drive device10is the same as that of the seventh embodiment.

According to the seventh to ninth embodiments described above, the parallel type drive device10can be provided. Note that an advantageous effect similar to that of the first embodiment can be obtained also by the drive device10of each of the seventh to ninth embodiments.

The effect as the first embodiment described above can be acquired.

The V type drive devices according to the fifth to sixth embodiments described above and the parallel type drive devices according to the seventh to ninth embodiments are not limited to a 2-cylinder type, but may be formed into a multiple cylinder type with four cylinders, six cylinders, or eight cylinders or even more.

In the embodiments described above, the first mount plane MP1and the second mount plane MP2in which the first drive unit and the second drive unit are arranged are each defined as a plane orthogonal to the central reference plane CRP, but they are not limited to this. They may be a plane crossing the central reference plane CRP at an angle greater or less than 90 degrees. In this case, the first crankshaft and the second crankshaft are not parallel to the central reference plane CRP, but are located to be inclined thereto. However, with use of, for example, a bevel gear as the coupler-synchronizing mechanism, the first crankshaft and the second crankshaft can be coupled with each other, to acquire opposite rotation outputs equal to each other but in opposite directions.

Tenth Embodiment

FIG. 13is a perspective view showing a drive device according to the tenth embodiment andFIG. 14is an exploded perspective view showing the XY separate crank mechanism. The tenth embodiment is different from the first embodiment in the structure of the XY separate crank mechanism.

As shown inFIG. 13, the drive device10comprises a first drive unit20acomprising a first crankshaft12a, a second drive unit20bcomprising a second crankshaft12band a coupler-synchronizing mechanism50which couples the first crankshaft12aand the second crankshaft12bwith each other, to rotate them in synchronous with each other.

The first drive unit20aand the second drive unit20bhave the same structure. The first drive unit20aand the second drive unit20bare arranged on both sides of the central reference plane CRP, respectively, and the first drive unit20aand the second drive unit20bare further arranged and configured to be symmetrical along left to right directions as well as front to rear directions (mirror arrangement) with respect to the central reference plane CRP. The first drive unit20ais located on one side of the central reference plane CRP and provided also in the first mount plane MP1orthogonal to the central reference plane CRP. The second drive unit20bis provided in the second mount plane MP2located on an opposite side of the central reference plane CRP and orthogonal to the central reference plane CRP, i.e., the second mount plane MP2symmetrical to the first mount plane MP1.

The first drive unit20acomprises a first crankshaft12aextending orthogonal to the first mount plane MP1, and a first XY separate crank mechanism30aprovided between a first piston24aand the first crankshaft12awithin the first mount plane MP1, which converts the reciprocating motion of the first piston24aand the rotary motion of the first crankshaft12ainto each other. The first direction which is the reciprocating direction of the first piston24ais defined as the first direction X1orthogonal to the central reference plane CRP. The first crankshaft12ais arranged substantially parallel to the central reference plane CRP.

The second drive unit20bcomprises a second crankshaft12bextending orthogonal to the second mount plane MP2and a second XY separate crank mechanism30bprovided between a second piston24band the second crankshaft12bwithin the second mount plane MP2, which converts the reciprocating motion of the second piston24band the rotary motion of the second crankshaft12binto each other. The second direction which is the reciprocating direction of the second piston24ais defined as the second direction X2symmetrical to the first direction X1described above and orthogonal to the central reference plane CRP. The first direction X1and the second direction X2make an angle of 180 degrees, that is, in the same direction, and the first piston24aand the second piston24barranged to be coaxial with each other.

The first XY separate crank mechanism30aand the second XY separate crank mechanism30bhave the same structure, and are arranged to be symmetrical along left to right directions as well as up and down directions with respect to the central reference plane CRP. Here, as a typical example, the second XY separate crank mechanism30bwill be described in detail. As shown inFIGS. 13 and 14, the second XY separate crank mechanism30bcomprises, in the second mount plane MP2including the central axis (the moving shaft, the X-axis) of the second piston24b, a second support member (combinator)32bprovided to be reciprocative along the second direction X2, a second crank connection member (crank connection plate)34bmounted to the second support member32bto be reciprocative along the fourth direction Y2(Y-axial direction) orthogonal to the second direction X2in the second mount plane MP2, and a second coupling rod36bas a coupling member, which couples the second piston24band the second support member32bwith each other. The movable central axis (the second direction X2) of the second support member32b, the movable central axis (fourth direction Y2) of the second crank connection member34b, and the central moving shaft (second direction X2) of the second coupling rod36bare located on the second mount plane MP2.

In this embodiment, the second support member32bis formed into a rectangular frame shape, for example. More specifically, the second support member32bcomprises a first support portion35aextending along the second direction X2, a second support portion35band a third support portion35c, extending respectively from both axial ends of the first support portion35aalong the fourth direction Y2. In this embodiment, the second support member32bcomprises, integrally as one unit, a fourth support portion35dwhich couples the extending end of the second support portion35band the extending end of the third support portion35cwith each other and opposes the first support portion35awith a gap therebetween. Inner surfaces of the second support portion35band the third support portion35c, which oppose each other, are formed to be flat and parallel to each other, and each extend along the fourth direction Y2. The second support member32bis formed by, for example, die-casting from aluminum.

A first linear slider41ais fixed to the first support portion35a. Further, a second guide rail45ais provided on an inner surface of the housing (not shown), to extend along the second direction X2within the second mount plane MP2. The first linear slider41ais supported and guided reciprocatively by the second guide rail45a. Thus, of the second support member32b, only the first support portion35ais supported on the second guide rail45areciprocatively along the second direction X2. The second linear slider41amay comprise a ball bearing built therein, which rollably contacts the second guide rail45a.

The second crank connection member34bis configured as a rectangular block-shaped member. The right and left side surfaces of the crank connection member34bform a first sliding surface60aand a second sliding surface60b. The first sliding surfaces60aand the second sliding surfaces60bare formed to be flat and parallel to each other and each extend along the fourth direction Y2.

A circular through-hole46is formed to penetrate substantially a central portion of the second crank connection member34b. The through-hole46extends in the Z-axial direction orthogonal to the second direction X2and the fourth direction Y2, i.e., a direction parallel to the second crankshaft12b. A crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46. The sliding surface, i.e., the inner surface of the through-hole46, is formed into a plain bearing by a lining process (plating) such as electroforming or electrodeposition. After the plating, wire-cut may be used.

The second crank connection member34bis placed in the frame-like second support member32b, and thus the first sliding surfaces60ais slidably in contact with the inner surface of the second support portion35b, and the second sliding surfaces60bis slidably in contact with the inner surface of the third support portion35c. Thus, the second crank connection member34bis supported and guided reciprocatively along the fourth direction Y2between the second and third support portions35band35cof the second support member32b. Further, the crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46of the second crank connection member34b. Thus, the second crank connection member34bengages with the second crankshaft12to connect the second crankshaft12band the second support member32bto each other.

Note that guide rails may by provided on the inner surfaces of the second support portion35band the third support portion35cof the second support member32b, respectively, to extend along the fourth direction Y2, and guide slots to engage the guide rails, may be formed, respectively, in the first sliding surfaces60aand the second sliding surfaces60bof the second crank connection member34b.

The second crank connection member34bcomprises two members (a first half portion64aincluding the first sliding surfaces60aand a second half portion64bincluding the second sliding surfaces60b) separated along separating planes62passing through the central axis of the through-hole46and crossing orthogonal to the second direction X2. When these two members are engaged with each other while the separating planes62meet each other, the rectangular block-shaped crank connection member34bis formed. The separating planes62are defined as planes which pass through the central axis of the through-hole46, and extend along the fourth direction Y2. Further, the separating planes62are each formed to have a projecting and recessed surface of a wavy, S-shaped, or cyclone configuration. The projections and recesses on each of the separating planes62are arranged alternately along the Z-axial direction (the axial direction of the through-hole46) and the projections and recesses each extend along the fourth direction Y2. In this embodiment, each separating plane62comprises arcurate projections and arcurate recesses arranged alternately. In the engaged state, the gap between the separating plane61of the first half portion64aand the separating planes61of the second half portion64bis about 100 μm. The first and second half portions64aand64bshould desirably be formed from a material which easy contains lubricating oil, for example, copper, brass or fine ceramic. Note that the first and second half portions64aand64bcan also be made from an engineering plastic such as ABS, followed by vapor deposition plating onto the surfaces thereof.

The separating planes62of the first half portion64aand the second half portion64beach may be formed to comprise two or more projections and/or two or more recesses. Moreover, it suffices only if the concave and convex are arranged along the Z-axial direction, and the shape of the concave and convex themselves is not limited to wavy, but may be changed into various forms.

One end of the second coupling rod36bof the second XY separate crank mechanism30bis coupled with the second piston24bvia a support pin, and another end is coupled with the second support portion35bof the second support member32b. The second coupling rod36bextends parallel to the second direction X2and in coaxial with the second piston24b. The second coupling rod36breciprocates together with the second support member32bas one unit along the second direction X2, to reciprocate the second piston24balong the second direction X2. Note that the connection member is not limited to a single coupling rod, but a plurality of coupling rods or a plate-shaped connection arm extending in the fourth direction Y2may be used as well.

When using the drive device10as an engine, driving force is applied to the second piston24b, and the second piston24breciprocates along the second direction X2. The reciprocating motion of the second piston24bis converted into rotary motion by the reciprocating motion of the second support member32balong the second direction X2and the reciprocating motion of the second crank connection member34balong the fourth direction Y2in the second XY separate crank mechanism30b, which is then transmitted to the second crankshaft12b. Thus, rotation force is applied to the second crankshaft12b.

As shown inFIG. 13, the first XY separate crank mechanism30ais configured as the second XY separate crank mechanism30b, and comprises a rectangular frame-shaped first support member32aprovided reciprocatively along the first direction X1, a block-shaped first crank connection member34asupported and guided in the first support member32ato be reciprocative along the third direction Y1, and a first coupling rod36awhich couples the first support member32aand the first piston24awith each other. A crankpin of the first crankshaft12ais rotatably penetrated through the through-hole of the first crank connection member34a.

The first XY separate crank mechanism30ais arranged and configured to be symmetrical to the second XY separate crank mechanism30bwith regard to the central reference plane CRP, and operates symmetrically with the second XY separate crank mechanism30b.

In the tenth embodiment, the other structure of the drive device10is the same as that of the first or second embodiment described above.

With the drive device10of the tenth embodiment configured as described above, the same advantageous effect as that of the drive device10of the first embodiment can be acquired. Further, according to the tenth embodiment, the support member in the XY separate crank mechanism is formed into a rectangular frame shape, and the crank connection member is disposed inside the frame slidably along the XYZ directions. With this structure, the linear guide can be omitted, making it possible to reduce the number of component members in the XY separate crank mechanism. Moreover, in the assembly, the crank connection member is divided and mounted on the crankshaft, and after the mounting, the crank connection member is mounted between the second support portion and third support portion of the support member. Thus, the crank connection member can be attached to the crankshaft40comprising a crankpin. Thus, the number of steps in the assembly of the crank mechanism can be reduced, and therefore the assembly is facilitated even in the case of multiple-cylinder types, thereby improving the assembling property. Furthermore, the support member and the crank connection member may be formed to have a function to automatically adjust to achieve sliding in an optimal position.

The crank connection member is divided to right and left into two along the central axis of the through-hole46, and the separating planes62are formed into irregular configuration. With this structure, even if there is a gap along the XY directions between the first half portion64aand the second half portion64bdivided, possible defects caused by mutual interference can be prevented. When the irregular configuration is formed as a wavy, S-shape, or cycloid, the mutual interference between the two members can be removed also in the ZY plane orthogonal to the Z-axial direction. When forming the clearance between the two members with a gap small as about 100 μm, the XY plane and ZY plane can be insulated from each other in terms of three-dimensional force.

FIG. 15compares in the stress acting on the crank connection member between the case (a) where the crank connection member is divided into two to have separating planes of irregular surface configuration as in this embodiment and the case (b) where the crank connecting member is undivided but an integrated one unit. As shown inFIG. 15, part (a), in the crank connection member of this embodiment, even if stress acts on the sliding surface of one half portion, the stress is insulated by the separating plane, and is not propagated to the other half portion; therefore deformation of the other half portion is not observed. Therefore, a side thrust loss is not created between the crank connection member and the support member, thereby making it possible to realize smooth sliding operation of the XY separate crank mechanism.

On the other hand, as shown inFIG. 15, part (b), in the case where the crank connection member is formed as an integral one unit, when stress acts on one sliding surface, the crank connection member deforms throughout itself. Therefore, a counter plane can be easily formed between the sliding surface of the crank connection member and the sliding surfaces of the support member, and a side thrust loss is produced between these sliding surfaces.

Eleventh Embodiment

FIG. 16is a perspective view showing a drive device according to the eleventh embodiment.FIG. 17is a perspective view of the drive device as viewed from an opposite side to that ofFIG. 16.FIG. 18is a partially exploded front view of the drive device. According to this embodiment, the drive device is configured as a double-shaft type compressor comprising a drive motor which rotates two crankshafts.

As shown inFIGS. 16 to 18, the drive device10as a compressor, comprises a rectangular box-shaped crankcase70, a cylinder block72provided on the crankcase70and comprising two cylinders22aand22b, a cylinder head74which covers top openings of the cylinders22aand22b, a first crankshaft12aand a second crankshaft12beach supported rotatably in the crankcase70. The crankcase70is installed on a plate base76.

In this embodiment, the two cylinders22aand22bare arranged parallel to each other, and each formed to have an equal inner diameter. Moreover, central axes of the cylinders22aand22bextend orthogonal to the base76. The cylinder head74comprises a first lead valve78awhich controls aspiration and exhaust of the air to and from the cylinder22a, and a second lead valve78bwhich controls aspiration and exhaust of the air to and from the cylinder22b.

The drive device10comprises a first drive unit20aincluding the first piston24aprovided in the cylinder22aand the first crankshaft12a, a second drive unit20bincluding the second piston24bprovided in the cylinder22band the second crankshaft12b, a coupler-synchronizing mechanism50which couples the first crankshaft12aand the second crankshaft12bwith each other to rotates the first crankshaft and the second crankshaft in synchronous with each other, a first drive motor80awhich drives (rotates) the first crankshaft12aand a second drive motor80bwhich drives (rotates) the second crankshaft12bin a direction opposite to that of the first crankshaft12a. The first drive motor80aand the second drive motor80bhave, for example, the same size and the same output and are arranged on the base76, respectively, on both sides of the crankcase70.

As shown inFIG. 18, the first drive unit20aand the second drive unit20bhave the same structure. The first drive unit20aand the second drive unit20bare arranged so that the first direction X1which is the moving direction of the first piston24aand the second direction X2which is the moving direction of the second piston24bare parallel each other. The first drive unit20aand the second drive unit20bare arranged respectively on both sides of central reference plane CRP and the first drive unit20aand the second drive unit20bare further arranged and configured to be symmetrical along left to right directions as well as front and rear directions with respect to the central reference plane CRP (mirror arrangement). The first drive unit20ais provided on the first mount plane MP1located on one side of central reference plane CRP and orthogonal to the central reference plane CRP, and the second drive unit20bis provided on the second mount plane MP2located on a side opposite of the central reference plane CRP and orthogonal to the central reference plane CRP, i.e., the second mount plane MP2symmetrical to the first mount plane MP1.

According to this embodiment, the first drive unit20acomprises a first crankshaft12aextending orthogonal to the first mount plane MP1, and a first XY separate crank mechanism30aprovided between the first piston24aand the first crankshaft12awithin the first mount plane MP1, which converts the reciprocating motion of the first piston24aand the rotary motion of the first crankshaft12ainto each other. The first direction which is the reciprocating direction of the first piston24ais defined as the first direction X1parallel to the central reference plane CRP. The first crankshaft12ais arranged substantially parallel to the central reference plane CRP.

The second drive unit20bcomprises a second crankshaft12bextending orthogonal to the second mount plane MP2and a second XY separate crank mechanism30bprovided between a second piston24band the second crankshaft12bwithin the second mount plane MP2, which converts the reciprocating motion of the second piston24band the rotary motion of the second crankshaft12binto each other. The second direction which is the reciprocating direction of the second piston24ais defined as the second direction X2parallel to the first direction X1described above and also parallel to the central reference plane CRP.

The first XY separate crank mechanism30aand the second XY separate crank mechanism30bhave the same structure, and are arranged to be symmetrical along left to right directions as well as up and down directions with respect to the central reference plane CRP. Here, as a typical example, the second XY separate crank mechanism30bwill be described in detail. As shown inFIGS. 18 and 19, the second XY separate crank mechanism30bcomprises, in the second mount plane MP2including the central axis (the moving shaft, the X-axis) of the second piston24b, a second support member (combinator)32bprovided to be reciprocative along the second direction X2, a second crank connection member (crank connection plate)34bmounted to the second support member32bto be reciprocative along the fourth direction Y2(Y-axial direction) orthogonal to the second direction X2in the second mount plane MP2, and a second coupling rod36bas a coupling member, which couples the second piston24band the second support member32bwith each other. The movable central axis (the second direction X2) of the second support member32b, the movable central axis (fourth direction Y2) of the second crank connection member34b, and the central moving shaft (second direction X2) of the second coupling rod36bare located on the second mount plane MP2.

In this embodiment, the second support member32bis formed into a rectangular frame shape, for example. More specifically, the second support member32bcomprises a first support portion35aextending along the second direction X2, a second support portion35band a third support portion35c, extending respectively from both axial ends of the first support portion35aalong the fourth direction Y2as one integral body. In this embodiment, the second support member32bcomprises a fourth support portion35dwhich couples the extending end of the second support portion35band the extending end of the third support portion35cwith each other and opposes the first support portion35awith a gap therebetween. Inner surfaces of the second support portion35band the third support portion35c, which oppose each other, are formed to be flat and parallel to each other, and each extend along the fourth direction Y2. The second support member32bis formed by, for example, die-casting from aluminum.

A second linear slider41ais fixed to the first support portion35a. Further, a second guide rail45ais provided on an inner surface of the crankcase70, to extend along the second direction X2within the second mount plane MP2. The second linear slider41ais supported and guided reciprocatively by the second guide rail45a. Thus, of the second support member32b, only the first support portion35ais supported on the second guide rail45areciprocatively along the second direction X2. The second linear slider41amay comprise a ball bearing built therein, which rollably contacts the second guide rail45a.

The second crank connection member34bis configured as a rectangular block-shaped member. The upper and lower side surfaces of the crank connection member34bform a first sliding surface60aand a second sliding surface60b, respectively. The first sliding surfaces60aand the second sliding surfaces60bare formed to be flat and parallel to each other and each extend along the fourth direction Y2.

A circular through-hole46is formed to penetrate substantially a central portion of the second crank connection member34b. The through-hole46extends in the Z-axial direction orthogonal to the second direction X2and the fourth direction Y2, i.e., a direction parallel to the second crankshaft12b. A crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46. The sliding surface, i.e., the inner surface of the through-hole46, is formed into a plain bearing by a lining process (plating) such as electroforming or electrodeposition. After the plating, wire-cut may be used.

The second crank connection member34bis placed in the frame-like second support member32b, and thus the first sliding surfaces60ais slidably in contact with the inner surface of the second support portion35b, and the second sliding surfaces60bis slidably in contact with the inner surface of the third support portion35c. Thus, the second crank connection member34bis supported and guided reciprocatively along the fourth direction Y2between the second and third support portions35band35cof the second support member32b. Further, the crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46of the second crank connection member34b. Thus, the second crank connection member34bengages with the second crankshaft12to connect the second crankshaft12band the second support member32bto each other.

Note that guide rails may by provided on the inner surfaces of the second support portion35band the third support portion35cof the second support member32b, respectively, to extend along the fourth direction Y2, and guide slots to engage the guide rails, may be formed, respectively, in the first sliding surfaces60aand the second sliding surfaces60bof the second crank connection member34b.

The second crank connection member34bcomprises two members (a first half portion64aincluding the first sliding surfaces60aand a second half portion64bincluding the second sliding surfaces60b) separated along separating planes62passing through the central axis of the through-hole46and crossing orthogonal to the second direction X2. When these two members are engaged with each other while the separating planes62meet each other, the rectangular block-shaped crank connection member34bis formed. The separating planes62are defined as planes which pass through the central axis of the through-hole46, and extend along the fourth direction Y2. Further, the separating planes62are each formed to have a projecting and recessed surface of a wavy, S-shaped, or cyclone configuration. The projections and recesses on each of the separating planes62are arranged alternately along the Z-axial direction (the axial direction of the through-hole46) and the projections and recesses each extend along the fourth direction Y2. In this embodiment, each separating plane62comprises arcurate projections and arcurate recesses arranged alternately. In the engaged state, the gap between the separating plane61of the first half portion64aand the separating planes61of the second half portion64bis about 100 μm. The first and second half portions64aand64bshould desirably be formed from a material which easy contains lubricating oil, for example, copper, brass or fine ceramic. Note that the first and second half portions64aand64bcan also be made from an engineering plastic such as ABS, followed by vapor deposition plating onto the surfaces thereof.

The separating planes62of the first half portion64aand the second half portion64beach may be formed to comprise two or more projections and/or two or more recesses. Moreover, it suffices only if the concave and convex are arranged along the Z-axial direction, and the shape of the concave and convex themselves is not limited to wavy, but may be changed into various forms.

One end of the second coupling rod36bof the second XY separate crank mechanism30bis coupled with the second piston24bvia a support pin, and another end is coupled with the second support portion35bof the second support member32b. The second coupling rod36bextends parallel to the second direction X2and in coaxial with the second piston24b. The second coupling rod36breciprocates together with the second support member32bas one unit along the second direction X2, to reciprocate the second piston24balong the second direction X2. Note that the connection member is not limited to a single coupling rod, but a plurality of coupling rods or a plate-shaped connection arm extending in the fourth direction Y2may be used as well.

As shown inFIGS. 18 and 19, the first XY separate crank mechanism30ais configured to be similar to the second XY separate crank mechanism30b, and comprises a rectangular frame-shaped first support member32aprovided reciprocatively along the first direction X1by the first linear slider40aand the first guide rail44a, a block-shaped first crank connection member34asupported and guided in the first support member32ato be reciprocative along the third direction Y1, and a first coupling rod36awhich couples the first support member32aand the first piston24awith each other. A crankpin of the first crankshaft12ais rotatably penetrated through the through-hole of the first crank connection member34a.

The first XY separate crank mechanism30aconfigured and the second XY separate crank mechanism30b, described above are provided in the crankcase70. The first XY separate crank mechanism30ais arranged and configured to be symmetrical to the second XY separate crank mechanism30bwith regard to the central reference plane CRP, and operates symmetrically with the second XY separate crank mechanism30b.

Both axial ends of the first crankshaft12arespectively penetrate side walls of the crankcase70and are each supported rotatably to the crankcase70by a bearing. The second crankshaft12bextends parallel to the first crankshaft12a, and both axial ends thereof penetrate the side walls of the crankcase70, respectively, to be supported rotatably by the bearings to the crankcase70.

As shown inFIGS. 16 to 18, the coupler-synchronizing mechanism50of the drive device10comprises a first gear52aattached coaxially to one end portion of the first crankshaft12aand a second gear52battached coaxially to one end portion of the second crankshaft12b. The first gear52aand the second gear52bare formed to have the same number of teeth and the same diameter, to be engaged with each other. The first crankshaft12aand the second crankshaft12bare coupled with each other via the first gear52aand the second gear52b. In order to avoid interference between the first gear52aand the second gear52band the base76, a slot81is formed in the base76and lower end portions of the first gear52aand the second gear52bare located in the slot81. When the first gear52arotates, the second gear52brotates with the first gear52ain an opposite direction in synchronous with rotation of the first gear52a. Thus, the first crankshaft12aand the second crankshaft12brotate synchronously in opposite directions to each other.

A first driven pulley82ais attached coaxially to the other end portion of the first crankshaft12a. A second driven pulley82ais attached coaxially to the other end portion of the second crankshaft12b. The first driven pulley82aand the second driven pulley82bare formed to have the same diameter. The first drive pulley84ais attached coaxially to a drive shaft81aof a first drive motor80a, and a first driving belt86ais looped over the first drive pulley84aand the first driven pulley82a. The second drive pulley84bis attached coaxially to a drive shaft81bof a second drive motor80b, and a second driving belt86bis looped over the second drive pulley84band the second driven pulley82b. The first drive pulley84aand the second drive pulley84bare formed to have the same diameter. The belt pulleys and driving belt described above each may as well be toothed pulleys and timing belt, respectively.

Note that the transmission mechanism which transmits the rotation force of the drive motor to the crankshaft may be configured from not only the combination of pulleys and belt, but also a combination of a sprocket and a chain.

In the drive device10configured as a compressor as described above, when the first drive motor80aand the second drive motor80bare operated, the rotation force of the first drive motor80ais applied to the first crankshaft12avia the first drive pulley, the first driving belt and the first driven pulley, and at the same time, the rotation force of the second drive motor80bis applied to the second crankshaft12bvia the second drive pulley, the second driving belt and the second driven pulley. Thus, rotation forces opposite to each other are applied to the first crankshaft12aand the second crankshaft12b, respectively, to rotate the first crankshaft12aand the second crankshaft12bin opposite directions. During this period, the first crankshaft12aand the second crankshaft12brotate in synchronous with each other by the coupler-synchronizing mechanism50. The crankpins of the crankshafts eccentricity rotate around the respective crankshafts.

The eccentric rotary motion of the crankpin16aof the first crankshaft12ais split into the reciprocating motion along the third direction Y1and the reciprocating motion along the first direction X1by the first crank connection member34aand the first support member32aof the first XY separate crank mechanism30a, and the reciprocating motion of the first support member32aalong the first direction X1is transmitted to the first piston24avia the first coupling rod36a. Thus, the first piston24areciprocates along the first direction X1in the first cylinder22ato compress the fluid in the first cylinder22aand then output the compressed fluid through the first lead valve78a.

Similarly, the eccentric rotary motion of the crankpin16bof the second crankshaft12bis split into the reciprocating motion along the fourth direction Y2and the reciprocating motion along the second direction X2by the second crank connection member34band the second support member32bof the second XY separate crank mechanism30band the reciprocating motion of the second support member32balong the second direction X2is transmitted to the second piston24bvia the second coupling rod36b. Thus, the second piston24breciprocates along the second direction X2in the second cylinder22bto compress the fluid in the second cylinder22band then output the compressed fluid through the second lead valve78b.

The first drive unit20aand the second drive unit20bare arranged to be symmetrical laterally and longitudinally with respect to the central reference plane CRP, and therefore they operate symmetrically. When the first piston24amoves to the top dead center, the second piston24balso moves synchronously to the top dead center. When the first piston24amoves toward the bottom dead center from the top dead center, the second piston24balso moves simultaneously from the top dead center toward the bottom dead center. The first XY separate crank mechanism30aand second XY separate crank mechanism30balso operate synchronously with each other while maintaining the symmetrical state with respect to the central reference plane CRP.

According to the drive device10configured as described above, the first and second XY separate crank mechanisms30aand30bof the first drive unit20aand the second drive unit20bsplit and convert the rotary motion of the first crankshaft12aand the rotary motion of the second crankshaft12binto the linear reciprocating motion along the first and second directions and the linear reciprocating motion along the third and fourth directions orthogonal to the first and second directions, respectively, thereby making it possible to achieve perfect parallel motion between the first piston24aand the second piston24b. Therefore, the uneven contact of the pistons to the cylinders can be avoided, thereby improving the sealing property, reducing the friction loss, and achieving high efficiency in side thrust lossless. Furthermore, since the first drive unit and the second drive unit are arranged and configured to be symmetrical along left to right directions as well as front to rear directions with respect to the central reference plane CRP (mirror arrangement), vibration caused by deviation can be completely canceled out, thereby making it possible to form a non-vibrating rotary structure.

Moreover, with the XY separate crank mechanism, the side thrust of the pistons can be substantially avoided, and as a result, the cylinders and pistons can be formed from a ceramic, glass or the like, thereby making it possible to structure a compressor with sufficient thermal efficiency at low temperature. Further, in the drive device, no vibration caused by side thrust is produced; therefore the cylinder can be formed from carbon fiber, or a plastic raw material such as PBT. Further, with being side thrustless, a higher aspect ratio of piston can be realized, and accordingly, a shorter stroke can be achieved, making it possible to obtain a small-sized and low-profile compressor or pump.

Further, according to the eleventh embodiment, the support member in the XY separate crank mechanism is formed into a U shaped frame, and the crank connection member is disposed inside the frame slidably along the XYZ directions. With this structure, the linear guide can be omitted, making it possible to reduce the number of component members in the XY separate crank mechanism. Moreover, in the assembly, the crank connection member is divided and mounted on the crankshaft, and after the mounting, the crank connection member is mounted between the second support portion and third support portion of the support member. Thus, the crank connection member can be attached to the first and second crankshafts12aand12beach comprising a crankpin. Thus, the number of steps in the assembly of the crank mechanism can be reduced, and therefore the assembly is facilitated even in the case of multiple-cylinder types, thereby improving the assembling property. Furthermore, the support member and the crank connection member may be formed to have a function to automatically adjust to achieve sliding in an optimal position.

The crank connection member is divided to right and left into two along the central axis of the through-hole46, and the separating planes62are formed into irregular configuration. With this structure, even if there is a gap along the XY directions between the first half portion64aand the second half portion64bdivided, possible defects caused by mutual interference can be prevented. When the irregular configuration is formed as a wavy, S-shape, or cycloid, the mutual interference between the two members can be removed also in the ZY plane orthogonal to the Z-axial direction. When forming the clearance between the two members with a gap small as about 100 μm, the XY plane and ZY plane can be insulated from each other in terms of three-dimensional force. At the same time, the two members can be automatically centered with each other along the Z-axial direction.

As described above, according to this embodiment, a mirror-type XY separate crank mechanism in which two crankshafts are combined with a gear or a belt to operate in opposite directions to suppress vibration, and a self-centering XYZ force separation mechanism are combined. With this structure, the friction loss and vibration are reduced, making it possible to obtain a high-efficiency compressor or pump. Further, the cylinders and pistons can be arranged respectively adjacent to each other, thereby facilitating collective piping. The conventional crosshead is not required and no substantial vibration is produced, and therefore the weight of the entire device can be reduced. Furthermore, the two crankshafts are in perfect synchronization and simultaneous positive and opposite rotations, and therefore the crankshafts can be driven with two independent drive motors. Therefore, small-sized and inexpensive motors can be employed as the drive motors.

Note that the number of drive motors is not limited to two, but a single drive motor may be used. In this case, the rotation force is applied to one of the crankshafts with the drive motor, and is transmitted to the other crankshaft by a coupler-synchronizing mechanism. Moreover, the shape of the pistons is not limited to circular, but it may as well be other non-circular shapes, for example, an oval, a rectangular shape with rounded corners, or other polygonal shape, or elliptical shape with a narrowed central portion.

Twelfth Embodiment

FIG. 20is a perspective view showing a front side of a drive device according to the twelfth embodiment.FIG. 21is a perspective view showing a rear side of the drive device.FIG. 22is a partially exploded front view of the drive device.FIG. 23is an exploded perspective view showing an XY separate crank mechanism of the drive device. According to this embodiment, the drive device is configured as a double-shaft engine device.

As shown inFIGS. 20 to 22, a drive device10is configured as an engine device which operates in, for example, two cycles. The drive device10comprises a rectangular box shaped crankcase70, a top cylinder block (first cylinder block)72aprovided on the crankcase70and comprising a first cylinder22aand a second cylinder22b, a cylinder-head cover (cam case)88which covers top openings of the first and second cylinders22aand22b, a lower cylinder block (second cylinder block)72bprovided under the crankcase70and comprising a third cylinder23aand a fourth cylinder23b, a valve casing90which covers lower openings of the third and fourth cylinders23aand23b, an air collector92provided on an bottom surface of the valve casing90, and a first crankshaft12aand a second crankshaft12beach supported rotatably in the crankcase70. In this embodiment, the first crankshaft12aand the second crankshaft12bare arranged to be parallel to each other.

In this embodiment, the two upper cylinders, namely, the first and second cylinders22aand22bare arranged to be parallel to each other and formed to have the same inner diameter. The two lower cylinders, namely, the third and fourth cylinders23aand23bare arranged to be parallel to each other and formed to have the same inner diameter. The inner diameter of the third and fourth cylinders23aand23bis greater than the inner diameter of the first and second cylinders22aand22b. Further, the first cylinder22aon an upper side and the third cylinder23aon a lower side are formed to be coaxial with each other and have a common central axis. The second cylinder22bon an upper side and the fourth cylinder23bon a lower side are formed to be coaxial with each other and have a common central axis.

The cylinder-head cover88comprises a combustion chamber94aformed therein to communicate to the top opening of the first cylinder22a, and comprising an air inlet port and an air outlet port each opened in the combustion chamber94a, and further a combustion chamber94bformed therein to communicate to the top openings of the second cylinder22band comprising an air inlet port and an air outlet port opened in the combustion chamber94b. Further, the cylinder-head cover88comprises a first charge-side valve mechanism96awhich opens/closes the air outlet port on a first cylinder22aside, a first discharge-side valve mechanism98awhich opens/closes the outlet port on a first cylinder22aside, a second charge-side valve mechanism96bwhich opens/closes the air inlet port on a second cylinder22bside, and a second discharge-side valve mechanism98bwhich opens/closes the outlet port on a second cylinder22bside.

The valve mechanisms96a,96b,98aand98bhave the same structure. The valve mechanisms each comprise, for example, a mushroom valve100as a valve body, a bulb slider102connected to a stem of the mushroom valve100, a linear guide104fixed to the cylinder-head cover88, which guides the bulb slider102slidably in opening and closing directions of the mushroom valve100, a valve spring106provided between the bulb slider102and the cylinder-head cover88, which urges the mushroom valve100toward a direction of a close position, a cam follower107attached rotatably to the bulb slider102, a rocker arm108attached swingably to the cylinder-head cover88and comprising one end abutting to the cam follower107, and a common cam shaft110comprising a plurality of cams in contact with the other end of the rocker arm108and the supported rotatably by the cylinder-head cover88.

On the other hand, the lower valve casing90comprises a first lead valve78awhich controls the aspiration of the air to the third cylinder23aand a second lead valve78bwhich controls the aspiration of the air to the fourth cylinder23b. Further, an exhaust lead valve79is provided in the valve casing90. The exhaust lead valve79controls exhaust of compression gas from the third cylinder23aand the fourth cylinder23b. The drive device10comprises an exhaust passage (exhaust piping)112extending from the exhaust lead valve79to two inlet ports of the cylinder-head cover88. In this embodiment, the exhaust passage112is defined a circulating pore continuously formed in the lower cylinder block72b, the crankcase70, the top cylinder block72aand the cylinder-head cover88. The compression gas discharged from the third cylinder23aand the fourth cylinder23bis supplied to the combustion chambers94aand94bof the first cylinder22aand the second cylinder22bvia the exhaust lead valve79, the exhaust passage112and the inlet ports of the cylinder-head cover88, as will be described later.

As shown inFIGS. 20 to 22, the drive device10comprises a first drive unit20awhich drives a first crankshaft12a, a second drive unit20bhaving the same structure as that of the first drive unit20a, which drives a second crankshaft12band a coupler-synchronizing mechanism50which couples the first crankshaft12aand the second crankshaft12bwith each other and synchronously rotates them. The first drive unit20aand the second drive unit20bare arranged on the respective sides of the central reference plane CRP and further the first drive unit20aand the second drive unit20bare arranged to be symmetrical along left to right as well as front to rear directions with respect to the central reference plane CRP (mirror arrangement). The first drive unit20ais located on one side of the central reference plane CRP and provided also in the first mount plane MP1orthogonal to the central reference plane CRP. The second drive unit20bis provided in the second mount plane MP2located on an opposite side of the central reference plane CRP and orthogonal to the central reference plane CRP, i.e., the second mount plane MP2symmetrical to the first mount plane MP1. The first crankshaft12aextends orthogonal to the first mount plane MP1, and the second crankshaft12bextends orthogonal to the second mount plane MP2.

The first drive unit20acomprises a first piston24aprovided reciprocatively in the first cylinder22a, the first crankshaft12adescribed above, a third piston25aprovided reciprocatively in the third cylinder23a, and a first XY separate crank mechanism30aprovided between the first piston24aand the first crankshaft and between the third piston25aand the first crankshaft, which converts the reciprocating motion of the first piston24aand the third piston25aand the rotary motion of the first crankshaft12ainto each other. The first direction which is the reciprocating direction of the first piston24aand the third piston25ais defined as the first direction X1parallel to the central reference plane CRP. Moreover, in this embodiment, the third piston25aon the lower side is formed to have a greater diameter than that of the first piston24aon the upper side, and further formed to have a greater aspect ratio.

The second drive unit20bcomprises a second piston24bprovided reciprocatively in the second cylinder22b, the second crankshaft12bdescribed above, a fourth piston25bprovided reciprocatively in the fourth cylinder23b, a second XY separate crank mechanism30bprovided between the second piston24band the second crankshaft12band between the fourth piston25band the second crankshaft, which converts the reciprocating motion of the second piston24band the fourth piston25band the rotary motion of the second crankshaft12binto each other. The second direction which is the reciprocating direction of the second piston24band the fourth piston25bis defined as the second direction X2parallel to the first direction X1and also parallel to the central reference plane CRP. In this embodiment, the fourth piston25bon the lower side is formed to have a greater diameter than that of the second piston24bon the upper side, and further formed to have a greater aspect ratio (diameter/height).

The first XY separate crank mechanism30aand the second XY separate crank mechanism30bhave the same structure, and are arranged to be symmetrical along left to right directions as well as up and down directions with respect to the central reference plane CRP. Here, as a typical example, the second XY separate crank mechanism30bwill be described in detail. As shown inFIGS. 22 and 23, the second XY separate crank mechanism30bcomprises, in the second mount plane MP2including the central axis (the moving shaft, the X-axis) of the second piston24band the central axis of the fourth piston25b, a second support member (combinator)32bprovided to be reciprocative along the second direction X2, a second crank connection member (crank connection plate)34bmounted to the second support member32bto be reciprocative along the fourth direction Y2(Y-axial direction) orthogonal to the second direction X2in the second mount plane MP2, a second coupling rod36bas a coupling member, which couples the second piston24band the second support member32bwith each other, and a fourth coupling rod37bas a coupling member, which couples the fourth piston25band the second support member32bwith each other. The movable central axis (the second direction X2) of the second support member32b, the movable central axis (fourth direction Y2) of the second crank connection member34b, and the central moving shafts (second direction X2) of the second and fourth coupling rods36band37bare located on the second mount plane MP2.

In this embodiment, the second support member32bis formed into a rectangular frame shape, for example. More specifically, the second support member32bcomprises a first support portion35aextending along the second direction X2, a second support portion35band a third support portion35c, extending respectively from both axial ends of the first support portion35aalong the fourth direction Y2. In this embodiment, the second support member32bcomprises, integrally as one unit, a fourth support portion35dwhich couples the extending end of the second support portion35band the extending end of the third support portion35cwith each other and opposes the first support portion35awith a gap therebetween. Inner surfaces of the second support portion35band the third support portion35c, which oppose each other, are formed to be flat and parallel to each other, and each extend along the fourth direction Y2. The second support member32bis formed by, for example, die-casting from aluminum.

A first linear slider41ais fixed to the first support portion35a. Further, a second guide rail45ais provided on an inner surface of the crankcase70, to extend along the second direction X2within the second mount plane MP2. The second linear slider41ais supported and guided reciprocatively by the second guide rail45a. Thus, of the second support member32b, only the first support portion35ais supported on the second guide rail45areciprocatively along the second direction X2. The second linear slider41amay comprise a ball bearing built therein, which rollably contacts the second guide rail45a.

The second crank connection member34bis configured as a rectangular block-shaped member. The upper and lower side surfaces of the crank connection member34bform a first sliding surface60aand a second sliding surface60b. The first sliding surfaces60aand the second sliding surfaces60bare formed to be flat and parallel to each other and each extend along the fourth direction Y2.

A circular through-hole46is formed to penetrate substantially a central portion of the second crank connection member34b. The through-hole46extends in the Z-axial direction orthogonal to the second direction X2and the fourth direction Y2, i.e., a direction parallel to the second crankshaft12b. A crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46. The sliding surface, i.e., the inner surface of the through-hole46, is formed into a plain bearing by a lining process (plating) such as electroforming or electrodeposition. After the plating, wire-cut may be used.

The second crank connection member34bis placed in the frame-like second support member32b, and thus the first sliding surfaces60ais slidably in contact with the inner surface of the second support portion35b, and the second sliding surfaces60bis slidably in contact with the inner surface of the third support portion35c. Thus, the second crank connection member34bis supported and guided reciprocatively along the fourth direction Y2between the second and third support portions35band35cof the second support member32b. Further, the crankpin16bof the second crankshaft12bis rotatably penetrated through the through-hole46of the second crank connection member34b. Thus, the second crank connection member34bengages with the second crankshaft12to connect the second crankshaft12band the second support member32bto each other.

Note that guide rails may by provided on the inner surfaces of the second support portion35band the third support portion35cof the second support member32b, respectively, to extend along the fourth direction Y2, and guide slots to engage the guide rails, may be formed, respectively, in the first sliding surfaces60aand the second sliding surfaces60bof the second crank connection member34b.

The second crank connection member34bcomprises two members (a first half portion64aincluding the first sliding surfaces60aand a second half portion64bincluding the second sliding surfaces60b) separated along separating planes62passing through the central axis of the through-hole46and crossing orthogonal to the second direction X2. When these two members are engaged with each other while the separating planes62meet each other, the rectangular block-shaped crank connection member34bis formed. The separating planes62are defined as planes which pass through the central axis of the through-hole46, and extend along the fourth direction Y2. Further, the separating planes62are each formed to have a projecting and recessed surface of a wavy, S-shaped, or cyclone configuration. The projections and recesses on each of the separating planes62are arranged alternately along the Z-axial direction (the axial direction of the through-hole46) and the projections and recesses each extend along the fourth direction Y2. In this embodiment, each separating plane62comprises arcurate projections and arcurate recesses arranged alternately. In the engaged state, the gap between the separating plane61of the first half portion64aand the separating planes61of the second half portion64bis about 100 μm. The first and second half portions64aand64bshould desirably be formed from a material which easy contains lubricating oil, for example, copper, brass or fine ceramic. Note that the first and second half portions64aand64bcan also be made from an engineering plastic such as ABS, followed by vapor deposition plating onto the surfaces thereof.

The separating planes62of the first half portion64aand the second half portion64beach may be formed to comprise two or more projections and/or two or more recesses. Moreover, it suffices only if the concave and convex are arranged along the Z-axial direction, and the shape of the concave and convex themselves is not limited to wavy, but may be changed into various forms.

One end of the second coupling rod36bof the second XY separate crank mechanism30bis coupled with the second piston24bvia a support pin, and another end is coupled with the second support portion35bof the second support member32b. The second coupling rod36bextends parallel to the second direction X2and in coaxial with the second piston24b. The second coupling rod36breciprocates together with the second support member32bas one unit along the second direction X2, to reciprocate the second piston24balong the second direction X2.

One end of the second coupling rod36bof the second XY separate crank mechanism30bis coupled with the second piston24bvia a support pin, and another end is coupled with the second support portion35bof the second support member32b. The second coupling rod36bextends parallel to the second direction X2and in coaxial with the second piston24b. The second coupling rod36breciprocates together with the second support member32bas one unit along the second direction X2, to reciprocate the second piston24balong the second direction X2.

One end of the fourth coupling rod37bof the second XY separate crank mechanism30bis coupled with the fourth piston25bvia a support pin, and another end is coupled with the third support portion35cof the second support member32b. The fourth coupling rod37bextends parallel to the second direction X2and in coaxial with the fourth piston25b. The fourth coupling rod37breciprocates together with the second support member32bas one unit along the second direction X2, to reciprocate the fourth piston25balong the second direction X2.

Note that the connection member is not limited to a single coupling rod, but a plurality of coupling rods or a plate-shaped connection arm extending in the fourth direction Y2may be used as well.

As shown inFIGS. 22 and 23, the first XY separate crank mechanism30ais configured to be similar to the second XY separate crank mechanism30b, and comprises a rectangular frame-shaped first support member32aprovided reciprocatively along the first direction X1by the first linear slider40aand the first guide rail44a, a block-shaped first crank connection member34asupported and guided in the first support member32ato be reciprocative along the third direction Y1, a first coupling rod36awhich couples the first support member32aand the first piston24awith each other, and a third coupling rod37awhich couples the first support member32aand the third piston25awith each other. A crankpin of the first crankshaft12ais rotatably penetrated through the through-hole of the first crank connection member34a.

The first crank connection member34acomprises two members (a first half portion including the first sliding surfaces and a second half portion including the second sliding surfaces) separated along separating planes62passing through the central axis of the through-hole and crossing orthogonal to the first direction X1. When these two members are engaged with each other while the separating planes62meet each other, the rectangular block-shaped crank connection member34ais formed. The separating planes62are defined as planes which pass through the central axis of the through-hole46, and extend along the fourth direction Y2. Further, the separating planes62are each formed to have a projecting and recessed surface of a wavy, S-shaped, or cyclone configuration. The projections and recesses on each of the separating planes62are arranged alternately along the Z-axial direction (the axial direction of the through-hole) and the projections and recesses each extend along the second direction Y1.

The first XY separate crank mechanism30aconfigured and the second XY separate crank mechanism30b, described above are provided in the crankcase70. The first XY separate crank mechanism30ais arranged and configured to be symmetrical to the second XY separate crank mechanism30bwith regard to the central reference plane CRP, and operates symmetrically with the second XY separate crank mechanism30b.

Both axial ends of the first crankshaft12arespectively penetrate side walls of the crankcase70and are each supported rotatably to the crankcase70by a bearing. The second crankshaft12bextends parallel to the first crankshaft12a, and both axial ends thereof penetrate the side walls of the crankcase70, respectively, to be supported rotatably by the bearings to the crankcase70.

As shown inFIGS. 20 to 22, the coupler-synchronizing mechanism50of the drive device10comprises a first gear52aattached coaxially to one end portion of the first crankshaft12aand a second gear52battached coaxially to one end portion of the second crankshaft12b. The first gear52aand the second gear52bare formed to have the same diameter and the same number of teeth, to be engaged with each other. The first crankshaft12aand the second crankshaft12bare coupled with each other via the first gear52aand the second gear52b. When the first gear52arotates, the second gear52brotates with the first gear52ain an opposite direction in synchronous with rotation of the first gear52a. Thus, the first crankshaft12aand the second crankshaft12brotate synchronously in opposite directions to each other.

A first timing pulley114ais attached coaxially to the other end portion of the first crankshaft12a. A second timing pulley114bis attached coaxially to the other end portion of the second crankshaft12b. A third timing pulley114ais attached coaxially to one end of the cam shaft110mounted to the cylinder-head cover88. Further, a rotatable idler pulley116is provided near the second timing pulley114b. The idler pulley116is supported by, for example, the crankcase70.

A cam timing belt114is looped over the first, second and third timing pulleys114a,114band114cand the idler pulley116. Toothed pulleys are used for the timing pulleys and the idler belt pulley116, respectively. For the timing belt114, a toothed belt with gears on both sides is used. With the first, second and third timing pulleys114a,114band114c, the idler belt pulley116and the cam timing belt114, the cam shaft110is rotated in synchronous with the rotation of the first and second crankshafts12aand12bto open/close the inlet-side and outlet-side valves at predetermined timings.

Note that the transmission mechanism for rotating the crankshaft110may be configured from not only the combination of toothed pulleys and toothed belt, but also a combination of a sprocket and a chain.

In the drive device10configured as an engine device as described above, at the starting-up, the first crankshaft12aand the second crankshaft12bare rotated by a motor or the like (not shown) to ascend and descend the first to fourth pistons24a,24b,25aand25b. For example, as shown inFIG. 22, while the first and second pistons24aand24bare moving to the top dead center from the bottom dead center, the first suction valve and the second suction valve are opened to supply air and fuel to the first and second cylinders22aand22band the combustion chambers94aand94bfrom the inlet ports, and thereafter the first suction valve and second suction valve are closed to compress the mixture gas of the fuel and air. Subsequently, the air-fuel mixture in the combustion chamber94aand94bis ignited by the ignition plugs95aand95b, respectively, to cause combustion and explosion to descend the first and second pistons24aand24btoward the bottom dead center from the top dead center. During this period, the first outlet valve and the second outlet valve are opened and the combustion gas is exhausted from the exhaust ports in the last half stage of the descending of the pistons. After the start-up, the air feed and combustion are repeated to reciprocatively drive the first and second pistons24aand24balong the first direction X1and the second direction X2. The reciprocating motion of the first and second pistons24aand24bis converted into rotary motions by the first XY separate crank mechanism30aand second XY separate crank mechanism30b, and the rotation forces are applied to each of the first and second crankshafts12aand12b, respectively. Thus, the first crankshaft12aand the second crankshaft12brotate in opposite directions to each Other. During this period, the first crankshaft12aand the second crankshaft12brotate in synchronous with each other by the coupler-synchronizing mechanism50.

Further, in synchronous with the reciprocating motion of the first and second pistons24aand24b, the third and fourth pistons25aand25bare driven reciprocatively along the first direction X1and the second direction X2. While the third and fourth pistons25aand25bare moving to the top dead center from the bottom dead center, the outside air is charged to the second cylinder23aand the fourth cylinder23bfrom the first lead valve78aand the second lead valve78b. While the third and fourth pistons25aand25bare moving to the bottom dead center from the top dead center, the air in the second cylinder23aand the fourth cylinder23bis compressed by the third and fourth pistons, and the compression gas is discharged to the exhaust passage112from the exhaust lead valve79. Then, the compression gas is sent to the inlet ports of the cylinder-head cover88via the exhaust passage112, and supplied to the combustion chambers94aand94bvia the first suction valve and second suction valve. As the third and fourth pistons25aand25brepeat the reciprocation motion along the first direction X1and the second direction X2, the air feed and discharging of the compression gas are repeated. Thus, the second and fourth cylinders23aand23band the second and fourth pistons25aand25bcan function as pumps or turbo superchargers.

The first drive unit20aand the second drive unit20bare arranged to be symmetrical along left to right well as front to rear directions with respect to the central reference plane CRP, and therefore they operate symmetrically. When the first piston24amoves to the top dead center, the second piston24balso moves synchronously to the top dead center. When the first piston24amoves toward the bottom dead center from the top dead center, the second piston24balso moves simultaneously from the top dead center toward the bottom dead center. Similarly, the second piston25aand the fourth piston25bascend and descend in synchronous with each other.

According to the drive device10configured as described above, the first and second XY separate crank mechanisms30aand30bof the first drive unit20aand the second drive unit20bsplit and convert the rotary motion of the first crankshaft12aand the rotary motion of the second crankshaft12binto the linear reciprocating motion along the first and second directions and the linear reciprocating motion along the third and fourth directions orthogonal to the first and second directions, respectively, thereby making it possible to achieve perfect parallel motion between the first piston24aand the second piston24band between the third piston25aand the fourth piston25b. Therefore, the uneven contact of the pistons to the cylinders can be avoided, thereby improving the sealing property, reducing the friction loss, and achieving high efficiency in side thrust lossless. Furthermore, since the first drive unit and the second drive unit are arranged and configured to be symmetrical along left to right directions as well as front to rear directions with respect to the central reference plane CRP (mirror arrangement), vibration caused by deviation can be completely canceled out, thereby making it possible to form a non-vibrating rotary structure.

Moreover, with the XY separate crank mechanism, the side thrust of the pistons can be substantially avoided, and as a result, the cylinders and pistons can be formed from a ceramic, glass or the like, thereby making it possible to structure an engine with sufficient thermal efficiency at low temperature. Further, in the drive device, no vibration caused by side thrust is produced; therefore the cylinder can be formed from carbon fiber, or a plastic raw material such as PBT. Further, with being side thrustless, a higher aspect ratio of piston can be realized, and accordingly, a shorter stroke can be achieved, making it possible to obtain a small-sized and low-profile engine.

Further, according to this embodiment, the support member in each of the XY separate crank mechanisms is formed into a U shaped frame, and the crank connection member is disposed inside the frame slidably along the XYZ directions. With this structure, the linear guide can be omitted, making it possible to reduce the number of component members in the XY separate crank mechanism. Moreover, in the assembly, the crank connection member is divided and mounted on the crankshaft, and after the mounting, the crank connection member is mounted between the second support portion and third support portion of the support member. Thus, the crank connection member can be attached to the first and second crankshafts12aand12beach comprising a crankpin. Thus, the number of steps in the assembly of the crank mechanism can be reduced, and therefore the assembly is facilitated even in the case of multiple-cylinder types, thereby improving the assembling property. Furthermore, the support member and the crank connection member may be formed to have a function to automatically adjust to achieve sliding in an optimal position.

The crank connection member is divided to right and left into two along the central axis of the through-hole46, and the separating planes62are formed into irregular configuration. With this structure, even if there is a gap along the XY directions between the first half portion64aand the second half portion64bdivided, possible defects caused by mutual interference can be prevented. When the irregular configuration is formed as a wavy, S-shape, or cycloid, the mutual interference between the two members can be removed also in the ZY plane orthogonal to the Z-axial direction. When forming the clearance between the two members with a gap small as about 100 μm, the XY plane and ZY plane can be insulated from each other in terms of three-dimensional force. At the same time, the two members can be automatically centered with each other along the Z-axial direction.

Furthermore, this embodiment comprises the third and fourth pistons which operate in synchronous with the first and second pistons, which are the combustion pistons, and the third and fourth pistons are configured as the supercharger (turbo-pump). With this structure, compression (pressurized) gas can be supplied to the combustion chambers together with fuel, thus improving the combustion efficiency. Thus, various types of engines devices such as two-cycle turbo-engines, four-cycle turbo-engines and diesel engines can be easily realized.

In this embodiment, the shape of the pistons is not limited to oval, but it may as well be other non-circular shapes, for example, a rectangular shape with rounded corners, or other polygonal shape, or elliptical shape with a narrowed central portion.

In the twelfth embodiment described above, the engine device is not limited to the two-cycle, but may be a four-cycle type.FIG. 24is a diagram schematically showing a turbocharger mechanism according to the first modification suitable for a four-cycle engine device.

As shown in the figure, the turbocharger mechanism comprises an outlet pipe130which forms an exhaust passage112. One end of the outlet pipe130is connected to the exhaust port of a second (third) cylinder23a(23b) on a lower side, and the other end is connected to the inlet port of a first (second) cylinder22a(22b) on an upper side. An intercooler124and an accumulate chamber126are provided for the outlet pipe130, and also a relief valve128is connected to the accumulate chamber126. Further, a carburetor120is connected to the inlet port of a second (third) cylinder23a(23b) on the lower side. In the case of a four-cycle engine device, the diameter of the third fourth pistons25aand25bis equal to or less than the diameter of the first and second pistons24aand24b.

In the turbocharger mechanism configured as described above, the air-fuel mixture supplied to the third and fourth cylinders23aand23bfrom the carburetor120are pressurized and compressed by the third and fourth pistons25aand25band then exhausted to the outlet pipe130. The compressed air-fuel mixture is cooled with the intercooler124and temporarily reserved in the accumulate chamber126. Thereafter, the mixture is supplied to the combustion chambers of the first and second cylinders22aand22bon the upper side via the outlet pipe130and the inlet ports.

Next, a turbocharger mechanism according to the second modification suitable for a four-cycle engine device will be described. In the following explanation, elements identical to those in the first modification will be denoted by the same reference numerals as in the first modification, respectively, and their detailed explanations will be omitted or simplified. Only elements different from those of the first modification will be mainly explained in detail.

FIG. 25is a diagram schematically showing a turbocharger mechanism according to the second modification.

According to the second modification, in an outlet pipe130of the turbocharger mechanism, an air flow meter132for control, a throttle134and a fuel injector136are provided in order between an accumulate chamber126and first and second cylinders22aand22b. Further, air feed pipes131are connected respectively to inlet ports of second and third cylinders23aand23bon a lower side, and the throttle134is provided in each of the air feed pipes131.

In the turbocharger mechanism configured as described above, the air supplied to the third and fourth cylinders23aand23bvia the throttles134is pressurized and compressed by the third and fourth pistons25aand25band then exhausted to the outlet pipe130. The compressed air is cooled with the intercooler124and temporarily reserved in the accumulate chamber126. Thereafter, the air is supplied to the combustion chambers of the first and second cylinders22aand22bon the upper side from the inlet ports via the air flow meter132and the throttle134. During this period, the fuel is injected to the compressed air by an injector136, and a mixture of the compressed air and the fuel is supplied to the combustion chambers.

According to the turbocharger mechanisms of the first and second modifications configured as described above, the air pressurized and compressed by the third and fourth pistons can be supplied together with fuel to the combustion chamber on the upper side, thereby improving the combustion efficiency. Note that the turbocharger mechanisms of the first and second modifications are applicable not only to four-cycle turboengine devices, but also to two-cycle engine devices, diesel engines, etc.

Next, an XY separate crank mechanism according to the third modification will be described. In the third modification, elements identical to those in the tenth to twelfth embodiments will be denoted by the same reference numerals as in the those embodiments, respectively, and their detailed explanations will be omitted or simplified. Only elements different from those of the embodiments will be mainly explained in detail.

FIG. 30is a perspective view showing the XY separate crank mechanism of the third modification andFIG. 31is an exploded perspective view of the XY separate crank mechanism. Of the two XY separate crank mechanisms, the structure of a second XY separate crank mechanism30bwill be described as a typical example.

As shown inFIGS. 30 and 31, according to the third modification, in the second XY separate crank mechanism30b, a roller bearing71is mounted in a through-hole46of a second crank connection member34band a crankpin16bof a crankshaft12is penetrated to the roller bearing71. The crankpin16bis engaged rotatably with the second crank connection member34bvia the roller bearing71.

In this case, the crankpin16bof the crankshaft12is formed as a separated member from the crankshaft12and one set of crank webs14b. In the assembly, the crankpin16bis penetrated to the roller bearing16band then fixed to the crank webs. Moreover, in the third modification, the support member (combinator)32bis fabricated into a rectangular frame shape as one unit. More specifically, the second support member32bcomprises a first support portion35aextending along the second direction, second and third support portions35band35cextending from both axial ends of the first support portion35aalong the fourth direction, and the extending end of the second support portion35band a fourth support portion35dwhich couples an extending end of the second support portion35band an extending end of the third support portion35cwith each other and opposes the first support portion35awith a gap therebetween, as one integral unit. Further, the second coupling rod36bas a connection member which couples the piston24band the support member32bwith each other is fabricated integrally with the support member32bas one unit.

The XY separate crank mechanism of the above-described structure is applicable to the XY separate crank mechanism of any of the tenth to twelfth embodiments described above. The crankpin16bis supported rotatably by the roller bearing71, and therefore the rotary motion of the crankpin16bis even smoother, thereby making it possible to achieve an XY separate crank mechanism suitable for high rotation speed engines and the like.

The present invention is not limited to the embodiments or modifications described above but the constituent elements of the invention can be modified in various manners without departing from the spirit and scope of the invention. Various aspects of the invention can also be extracted from any appropriate combination of a plurality of constituent elements disclosed in the embodiments. Some constituent elements may be deleted in all of the constituent elements disclosed in the embodiments. The constituent elements described in different embodiments may be combined arbitrarily.