Patent ID: 12247659

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a continuously variable transmission of the present invention will be described with reference to the accompanying drawings.

As illustrated inFIGS.1and2, the continuously variable transmission10includes a drive pulley16, a driven pulley17, a metal belt18wound around the drive pulley16and the driven pulley17, a parking lock device, and a transmission case11housing the above.

The transmission case11includes a first case12whose one end surface is joined to an engine (not illustrated), and a second case13that is joined to close the other end surface of the first case12. The first case12and the second case13support an input shaft14and an output shaft15in parallel to each other. A drive pulley16provided to the input shaft14positioned on the lower side and a driven pulley17provided to the output shaft15positioned on the upper side are wound around by a metal belt18.

As illustrated inFIG.10, the metal belt18is configured by annularly coupling a plurality of elements31made from a metal plate with a pair of left and right endless laminated rings32made of a metal. Each of the laminated rings32is formed by laminating a plurality of metal rings33made from thin steel.

As illustrated inFIG.3, the driven pulley17includes: a fixed-side pulley half19fixed to the output shaft15in a manner facing an inner wall13aof the second case13; and a movable-side pulley half20supported on the output shaft15in a manner not relatively rotatable but axially slidable, and capable of approaching and separating from the fixed-side pulley half19by hydraulic pressure. Similarly, as illustrated inFIG.9, the drive pulley16includes a fixed-side pulley half40and a movable-side pulley half39. By changing the groove width of the drive pulley16and the groove width of the driven pulley17, the effective radii of both the pulleys16and17are changed, and the transmission ratio is changed continuously.

Next, the structure of a parking lock device for restraining the rotation of the output shaft15when stopping the vehicle will be described with reference toFIGS.3to5.

As illustrated inFIGS.2and3, the back surface of the fixed-side pulley half19of the driven pulley17is integrally formed with an annular parking gear21protruding toward the inner wall13aof the second case13. The outer peripheral surface of the parking gear21is formed with a plurality of tooth grooves21a. Referring also toFIG.4, the transmission case11is provided with a parking pawl23bent in a V shape in a manner facing the parking gear21on the radially outer side of the outer peripheral surface of the driven pulley17. The intermediate portion of the parking pawl23is swingably supported by a support shaft22fixed to an inner wall12aof the first case12and the inner wall13aof the second case13. The tip end of the parking pawl23is formed with a locking claw23aengageable with one of the tooth grooves21aof the parking gear21. The parking pawl23is biased clockwise inFIG.2by the elastic force of a torsion spring24wound around the outer periphery of the support shaft22, such that the locking claw23ais separated from the tooth grooves21aof the parking gear21. The base end side of the parking pawl23is formed with a cam surface23bin contact with a conical cam member26of the parking rod25.

As illustrated inFIG.5, the parking rod25penetrates through a through hole12bformed in the inner wall12aof the first case12into the second case13. The cam member26is provided at the tip end of the parking rod25. The parking rod25is coupled to a shift lever (or actuator) (not illustrated) and is axially movable. The cam member26of the parking rod25is guided by the through hole12bof the inner wall12aand an arc-shaped guide surface28aof a guide member28fixed to the inner wall12aby two bolts27,27.

When the driver selects a range other than the parking range with the shift lever, the parking pawl23is in a non-actuated position due to the elastic force of the torsion spring24, the locking claw23aof the parking pawl23is separated from the tooth groove21aof the parking gear21, the restraint of the output shaft15is released, and the parking lock device comes into a non-actuated state. When the driver selects the parking range with the shift lever, the cam member26protrudes from the through hole12b, and the cam surface26apresses the cam surface23bformed on the base end side of the parking pawl23(seeFIG.5). As a result, the parking pawl23swings counterclockwise around the support shaft22inFIG.2, the locking claw23aengages with one of the tooth grooves21aof the parking gear21, the rotation of the output shaft15is restrained as illustrated inFIG.2, and the parking lock device is actuated.

At this time, if a foreign matter intrudes the transmission case11or a fragment of a component disposed inside the transmission case11, for example, a metal ring33, falls off and becomes a foreign matter, the locking claw23aof the parking pawl23or the parking gear21may be damaged or a failure may occur if the foreign matter intrudes and/or approaches the parking gear21. The transmission case11is provided with a foreign matter intrusion prevention structure for preventing intrusion of foreign matters into the parking gear21.

Hereinafter, the foreign matter intrusion prevention structure for preventing intrusion of foreign matter into the parking gear21will be described. In the following description, the broken metal belt18is assumed as the foreign matter.

The foreign matter intrusion prevention structure is formed by combining a foreign matter intrusion prevention structure centered on an annular rib51provided in the vicinity of the driven pulley17and a foreign matter intrusion prevention structure formed by an auxiliary rib54provided in the vicinity of the drive pulley16, either of which may be used alone.

The foreign matter intrusion prevention structure in the vicinity of the driven pulley17is integrally molded with the second case13, and is configured with a wall surface rising axially from the inner wall13a. As illustrated inFIG.2, the foreign matter intrusion prevention structure includes a circular annular rib51, a plurality of radial ribs52extending radially outward from the annular rib51around the axis of the output shaft15, a coupling rib53extending from the lower portion of the annular rib51and coupled to the lower end of the second case13, and an isolated rib55disposed in the vicinity of the parking pawl23. InFIG.2, the annular rib51, the radial ribs52, the coupling rib53, and the isolated rib55are hatched for easy understanding.

The annular rib51is integrally molded with the second case13in a manner surrounding the outer periphery of the parking gear21except for a position intersecting the swing trajectory of the parking pawl23and a predetermined position. The annular rib51preferably covers the outer periphery of the parking gear21by at least 180 degrees. In this case, the annular rib51does not need to continuously cover the outer periphery of the parking gear21by 180 degrees or more, and may be discretely arranged to cover the outer periphery of the parking gear21by 180 degrees or more as a whole. The annular rib51of the present embodiment has a first opening51aprovided at the position intersecting the swing trajectory of the parking pawl23, and a second opening51bprovided at a position not overlapping the region obtained by objecting the movement trajectory of the metal belt18and below the first opening51a.

By surrounding the outer periphery of the parking gear21with the annular rib51in this manner, foreign matter such as fragments of the metal belt18of the continuously variable transmission10can be prevented from intruding and/or approaching the parking gear21even if the metal belt18is broken. Further, the annular rib51can be integrally molded with the second case13, which improves the cost and the productivity without the need of using a separate component. Further, the first opening51acan avoid interfering with the swinging of the parking pawl23, and a foreign matter entering the inside of the annular rib51can be discharged from the second opening51b. Further, the second opening51bis provided at a position that does not overlap the projected region of the movement trajectory of the metal belt18, which can prevent foreign matters from entering the inside of the annular rib51from the second opening51beven if the metal belt18is broken.

As illustrated inFIG.6, an inner diameter D1of the annular rib51is larger than an outer diameter D2of the parking gear21and equal to or smaller than an outer diameter D3of the driven pulley17. A gap T1between the annular rib51and the fixed-side pulley half19of the driven pulley17is smaller than a width T2of the metal rings33constituting the metal belt18. Accordingly, a broken metal ring33can be prevented from entering the gap between the annular rib51and the fixed-side pulley half19of the driven pulley17.

The present embodiment is provided with six radial ribs52, four provided to the left of the parking gear21at equal intervals, one provided to the lower right of the parking gear21, and the remaining one provided to the upper right. Hereinafter, the radial rib52provided to the upper right among the six radial ribs52is referred to as a shielding rib56. The shielding rib56is not necessarily the radial ribs52, and is not necessarily continuous from the annular rib51.

Returning toFIG.2, the shielding rib56extends from one end of the first opening51aof the annular rib51toward the support shaft22as the swing fulcrum of the parking pawl23. The tip end of shielding rib56has a gap from the parking gear21equal to or smaller than a predetermined width, preferably, equal to or smaller than the width T2of the metal rings33in a state where the parking pawl23is not fitted. Accordingly, fragments of the metal ring33broken on the side closer to the drive pulley16can be prevented from scattering toward the parking gear21.

In the present embodiment, the tip end of the shielding rib56has a shape warped toward the drive pulley16. Thereby, fragments of the broken metal ring33hit the shielding rib56and can be prevented from intruding the parking gear21.

Referring also toFIG.7, the isolated rib55isolated from the shielding rib56is provided closer to the drive pulley16than is the shielding rib56. The isolated rib55is disposed below the parking pawl23in a manner facing the shielding rib56.

Here, the parking pawl23is provided with a projection23cat the lower portion thereof. Accordingly, the parking pawl23can be brought close to the shielding rib56and the isolated rib55. That is, the tip end of the shielding rib56can have a gap from the parking gear21equal to or smaller than the predetermined width in the state where the parking pawl23is not fitted, while the tip end of the isolated rib55can have a gap from the parking gear21equal to or smaller than the predetermined width, preferably, equal to or smaller than the width T2of the metal rings33in the state where the parking pawl23is not fitted.

Accordingly, the parking pawl23, the isolated rib55, and the shielding rib56, can form a labyrinth gap, and the fragments of the metal ring33broken on the side closer to the drive pulley16can be more reliably prevented from scattering toward the parking gear21.

The coupling rib53extends from the lower portion of the annular rib51and is coupled to the lower end of the second case13. More specifically, the coupling rib53is formed continuously from the annular rib51to the lower end of the first case12without a break. Accordingly, fragments of the metal rings33broken on the side closer to the drive pulley16can be prevented from scattering from the lower side of the driven pulley17toward the parking gear21.

According to such a foreign matter intrusion prevention structure in the vicinity of the driven pulley17, since the outer peripheral surface of the parking gear21is covered with the annular rib51, foreign matters can be prevented from intruding and/or approaching the parking gear21and the parking pawl23. In particular, the broken metal ring33, which is an elongated flexible foreign matter, is prevented from intruding and/or approaching the outer periphery of the parking gear21. Accordingly, damage to the parking lock device and occurrence of failure can be avoided more reliably.

Further, since the lower portion of the annular rib51is formed with the second opening51b, a foreign matter intruding the inside from the first opening51aof the annular rib51can be discharged from the second opening51bto the outside, thereby prevented from staying in the annular rib51.

On the other hand, the foreign matter intrusion prevention structure in the vicinity of the drive pulley16is integrally molded with the first case12, and is configured with a wall surface rising axially from the inner wall12a. As illustrated inFIGS.8and9, the foreign matter intrusion prevention structure includes the auxiliary rib54extending from the guide support12cholding the guide member28toward the drive pulley16.

As illustrated inFIG.8, the auxiliary rib54is integrally molded with the guide support12cholding the guide member28, and extends downward from the guide support12ctoward the drive pulley16. The auxiliary rib54is formed such that the gap between the tip end thereof and the drive pulley16is equal to or smaller than a predetermined width, preferably equal to or smaller than the width T2of the metal rings33. Accordingly, fragments of the metal ring33broken on the side closer to the drive pulley16can be prevented from scattering from the drive pulley16toward the parking gear21.

The guide member28bolt-fastened to the guide support12cincludes a guide extension28bprotruding from the lower surface of the guide support12ctoward the drive pulley16. Accordingly, fragments of the metal ring33broken on the side closer to the drive pulley16can be further prevented from scattering from the drive pulley16toward the parking gear21.

On the other hand, the lower surface of the guide support12cis inclined upward toward the auxiliary rib54. A space57is formed between the lower surface of the guide support12cand the auxiliary rib54. The guide extension28bof the guide member28covers at least a part of the side surface of the auxiliary rib54.

According to the foreign matter intrusion prevention structure in the vicinity of the drive pulley16, since the space57is covered from the lateral side by the guide extension28b, fragments of the metal ring33captured in the space57can be prevented from bypassing the auxiliary rib54from the lateral side and scattering toward the parking gear21.

The auxiliary rib54is not necessarily formed continuously from the guide support12c, and may be separated from the guide support12c. In this case, the distance between the guide support12cand the auxiliary rib54is preferably equal to or smaller than the width T2of the metal rings33.

Although various embodiments have been described above with reference to the drawings, it is needless to say that the present invention is not limited to these examples. It is apparent that those skilled in the art may conceive of various modifications and changes within the scope described in the claims, and it is understood that such modifications and changes naturally fall within the technical scope of the present invention. In addition, respective constituent elements in the above-described embodiment may be freely combined without departing from the gist of the invention.

In the present specification, at least the following matters are described.

Corresponding constituent elements and the like in the embodiments described above are shown in parentheses, but the present invention is not limited thereto.(1) A continuously variable transmission (continuously variable transmission10) including, in a case (transmission case11):a drive pulley (drive pulley16) and a driven pulley (driven pulley17) each including a fixed-side pulley half (fixed-side pulley half19,40) and a movable-side pulley half (movable-side pulley half20,39) configured to move axially relative to the fixed-side pulley half;a belt (metal belt18) including a plurality of elements (elements31) and a plurality of rings (metal rings33) wound around the drive pulley and the driven pulley;a parking gear (parking gear21) provided to the fixed-side pulley half of the driven pulley; anda parking pawl (parking pawl23) configured to be fitted to the parking gear by swinging,the continuously variable transmission transmitting a driving force from a drive source to a wheel while changing a transmission ratio by changing groove widths of the drive pulley and the driven pulley, in which the case includes an annular rib (annular rib51) integrally molded with the case in a manner surrounding an outer periphery of the parking gear except for a position intersecting a swing trajectory of the parking pawl and a predetermined position.

According to (1), by surrounding the outer periphery of the parking gear with the annular rib, foreign matters can be prevented from intruding and/or approaching the parking gear even if the belt of the continuously variable transmission is broken, which can prevent occurrence of failure. Further, the annular rib can be integrally molded with the case, which improves the cost and the productivity without the need of using a separate component.(2) The continuously variable transmission according to (1), in which the annular rib hasa first opening (first opening51a) provided at the position intersecting the swing trajectory of the parking pawl, anda second opening (second opening51b) provided at a position not overlapping a region obtained by objecting the movement trajectory of the belt and below the first opening.

According to (2), the first opening can avoid interfering with the swinging of the parking pawl, and a foreign matter entering the inside of the annular rib can be discharged from the second opening. Further, the second opening is provided at a position not overlapping the region obtained by objecting the movement trajectory of the belt, which can prevent foreign matters from entering the inside of the annular rib from the second opening even if the belt is broken.(3) The continuously variable transmission according to (1), in whichan inner diameter (inner diameter D1) of the annular rib is larger than an outer diameter (outer diameter D2) of the parking gear and is equal to or smaller than an outer diameter (outer diameter D3) of the driven pulley.

According to (3), foreign matters can be prevented from intruding and/or approaching the parking gear, which can prevent occurrence of failure.(4) The continuously variable transmission according to (1), in whicha gap (gap T1) between the annular rib and the fixed-side pulley half of the driven pulley is smaller than a width (width T2) of the rings constituting the belt.

According to (4), a broken ring can be prevented from entering the gap between the annular rib and the fixed-side pulley half of the driven pulley.(5) The continuously variable transmission according to (1), in whichthe annular rib covers the outer periphery of the parking gear by at least 180 degrees.

According to (5), by sufficiently covering the outer periphery of the parking gear, foreign matters can be further prevented from intruding and/or approaching the parking gear, which can prevent occurrence of failure.(6) The continuously variable transmission according to (1), in whichthe case includes a shielding rib (shielding rib56) extending from the annular rib, andthe shielding rib extends toward a swing fulcrum of the parking pawl, and has a tip end having a gap from the parking gear equal to or smaller than a predetermined width in a state where the parking pawl is not fitted.

According to (6), fragments of the ring broken on the side closer to the drive pulley can be prevented from scattering toward the parking gear.(7) The continuously variable transmission according to (6), in whichthe shielding rib has a shape warped toward the drive pulley.

According to (7), fragments of the broken ring hit the shielding rib and can be prevented from intruding the parking gear.(8) The continuously variable transmission according to (7), in whichthe case includes an isolated rib (isolated rib55) provided on a side closer to the drive pulley than is the shielding rib and isolated from the shielding rib,the parking pawl includes a projection (projection23c) at a lower portion thereof,the projection is provided between the isolated rib and the shielding rib, anda gap between the projection and the isolated rib is equal to or smaller than a predetermined width in the state where the parking pawl is not fitted.

According to (8), fragments of the ring broken on the side closer to the drive pulley can be further prevented from scattering toward the parking gear.(9) The continuously variable transmission according to (1), in whichthe case includes a coupling rib (coupling rib53) extending from a lower portion of the annular rib and coupled to a lower end of the case.

According to (9), fragments of the ring broken on the side closer to the drive pulley can be prevented from scattering from the lower side of the driven pulley toward the parking gear.(10) The continuously variable transmission according to (9), in whichthe coupling rib is formed continuously from the annular rib to the lower end of the case without a break.

According to (10), fragments of the ring broken on the side closer to the drive pulley can be further prevented from scattering from the lower side of the driven pulley toward the parking gear.(11) The continuously variable transmission according to (1), further including, in the case:a parking rod (parking rod25) configured to swing the parking pawl; anda guide member (guide member28) configured to guide the parking rod, in which the case includesa guide support (guide support12c) supporting the guide member, andan auxiliary rib (auxiliary rib54) extending from the guide supporting portion and having a gap from the drive pulley equal to or smaller than a predetermined width.

According to (11), fragments of the ring broken on the side closer to the drive pulley can be prevented from scattering from the guide member toward the parking gear.(12) The continuously variable transmission according to (11), in whichthe guide member includes a guide extension (guide extension28b) extending toward the drive pulley.

According to (12), fragments of the ring broken on the side closer to the drive pulley can be further prevented from scattering from the guide member toward the parking gear.(13) The continuously variable transmission according to (12), in whichthe guide extension covers at least a part of a side surface of the auxiliary rib.

According to (13), fragments hitting the auxiliary rib can be prevented from further scattering.