A linear-reciprocating device 10 has a moving block 13 which is attached to a guide rail 12 provided to a support base 11 so as to freely reciprocate, ball rolling grooves 23a and 23b which form ball rolling paths 24a and 24b together with ball rolling grooves 21a and 21b are provided to a base end of the moving block 13, and ball circulation holes 25a and 25b which are communicated to the ball rolling paths 24a and 24b are provided to a base end. In a longitudinal-directional middle area of the moving block 13, return blocks 32a and 32b which communicate between the ball rolling paths 24a and 24b and the ball circulation holes 25a and 25b are provided. The moving block 13 moves to a position at which the moving block 13 is moved to a position at which the moving block is protruded from a distal end of the guide rail 12.

TECHNICAL FIELD

The present invention relates to a linear-reciprocating device for linearly reciprocating a moving block along a guide rail so as to interpose a lot of balls between the moving block and the guide rail.

BACKGROUND ART

In order to linearly reciprocate an object to be transported such as a workpiece or a jig and a tool, a linear-reciprocating device is used so as to linearly reciprocate a moving block such as a slider or a table, to which the object to be transported is attached, along a guide rail of a support base. The support base is provided with a drive rod that reciprocates freely in a longitudinal direction of the support base, a protruding end of the drive rod is connected to a distal end of a moving member by a connection block, and the moving member is linearly reciprocated by the reciprocation of the drive rod. The drive rod is driven by a driving source such as a pneumatic cylinder or an electric motor.

By attaching the moving block to the guide rail via balls so as to interpose a lot of balls between the moving block and the guide rail, the moving block which reciprocates along the guide rail can be driven with a small rolling resistance. A lot of balls are housed inside a ball rolling path which is formed of a rolling groove having an almost semicircular shape and being provided to the moving block and a rolling groove having an almost semicircular shape and being provided to the guide rail, and the balls are moved while rolling inside the ball rolling path when the moving block is driven.

The following two types are known as such a ball slider that the moving block is attached to the guide rail via the balls. One of them is an infinite guide type provided with a return hole, that is, a ball circulation hole provided separately from the ball rolling path for circulating the balls between the ball circulation hole and the ball rolling path. The other is a finite guide type in which the balls are not circulated. Patent Document 1 describes the infinite guide type ball slider.

PRIOR ART DOCUMENT

Patent Document

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

In a conventional infinite guide type ball slider, return lid members which communicate between the ball rolling path and the ball circulation hole are provided to both ends of the moving block. Therefore, when the moving block is moved to a position at which the moving block is protruded from an end of the guide rail, the balls fall out of the ball rolling groove, and therefore, the moving block cannot be driven to a position at which an end of the moving block is protruded from the guide rail.

For example, in a linear-reciprocating device of such a type that the driving source for driving the moving block is housed in the support base provided with the guide rail, the moving block is protruded from a distal end of the support base or guide rail when the drive rod driven by the driving source so as to be protruded from the support base is connected to the moving block. Practically, such a protruding structure is impossible, and therefore, the following structure is practically adopted. It is required to protrude a drive member reciprocated by the driving source inside the support base from a slit formed on the guide rail so that a slider or the drive member is engaged with an inner surface of the moving block, and therefore, the structure of the guide rail is complicated. If the structures of the guide rail and the slider are complicated, their heights are increased, and therefore, the linear-reciprocating device cannot be downsized.

A preferred aim of the present invention is to achieve the downsizing of the linear-reciprocating device.

Means for Solving the Problems

A linear-reciprocating device of the present invention has a feature of a linear-reciprocating device for linearly reciprocating a moving block attached to a guide rail provided to a support base so as to freely reciprocate, and the linear-reciprocating device includes: a first ball rolling groove formed on a side surface of the guide rail so as to face a side surface of a guide groove which is formed on an inner surface of the moving block and into which the guide rail is inserted; a second ball rolling groove formed on a base end side of the guide groove and forming a ball rolling path together with the first ball rolling groove; a lot of balls housed in the ball rolling path and in a ball circulation hole formed along the ball rolling path; a return lid member provided to a base end of the moving block to form a base-end-side ball return path for communication between the ball rolling path and the ball circulation hole; and a return block provided to a longitudinal-directional middle area of the moving block to form a middle-side ball return path for communication between the ball rolling path and the ball circulation hole. In the linear-reciprocating device, the moving block is guided by the balls to a position at which a distal end of the moving block is protruded from a distal end of the guide rail.

The linear-reciprocating device of the present invention has such a feature that an attachment concave portion to which the return block is attached is formed in a longitudinal-directional middle area of an inner surface of the moving block. The linear-reciprocating device of the present invention has such a feature that an abutment surface on which the return block is abutted is formed in a longitudinal-directional middle area of an inner surface of the moving block. The linear-reciprocating device of the present invention has such a feature that the first ball rolling groove is provided to both sides of the guide rail, and that the second ball rolling groove is provided to both side surfaces of the guide groove of the moving block. The linear-reciprocating device of the present invention has such a feature that the two return lid members provided to both sides of the moving block are integrally formed with each other by a connecting portion.

The linear-reciprocating device of the present invention has such a feature that the two return blocks provided to both sides of the moving block are integrally formed with each other by a connecting portion. The linear-reciprocating device of the present invention has such a feature that the ball circulation hole is formed at a horizontal position along a surface of the guide rail with respect to the ball rolling path. The linear-reciprocating device of the present invention has such a feature that a guide fit hole in which a return groove is formed on each of the return lid member and the return block is provided, and that a return groove for forming the ball return path together with the above-described return groove is provided to a return guide fitted into the guide fit hole. The linear-reciprocating device of the present invention has such a feature that the return guides attached to the return lid member and the return block are formed in the same shape as each other. The linear-reciprocating device of the present invention has such a feature that a drive rod provided to the support base is connected to a distal end of the moving block, and that the moving block is reciprocated by the drive rod protruded from a distal end surface of the support base.

Effects of the Invention

In a linear-reciprocating device of the present invention, a ball rolling path is formed of a first ball rolling groove provided to a guide rail and a second ball rolling groove provided on a base end side of a moving block. A ball circulation hole which is communicated into the ball rolling path is provided to the base end. A middle-side ball return path which communicates between the ball rolling path and the ball circulation hole is provided in a longitudinal-directional middle area of the moving block. Therefore, the moving block can be moved to a position at which the moving block is protruded while rolling balls from a distal end of the guide rail.

Since the moving block can be moved to the position at which the moving block is protruded from the distal end of the guide rail, a drive rod for driving the moving block can be provided to a support base, and the drive rod can be connected to a distal end of the moving block. In this manner, in comparison with a case that the drive source and the moving block are connected to each other inside the support base, a structure of the linear-reciprocating device is not complicated, and the linear-reciprocating device can be downsized by forming a thickness of the structure to be thin. Since the guide rail is provided to the support base, the drive source for driving the drive rod can be protruded into the guide rail so as to downsize the linear-reciprocating device including the guide rail and the support base.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described in detail based on drawings. As illustrated inFIGS. 1 and 2, a linear-reciprocating device10includes a support base11. As illustrated inFIGS. 4 and 5, in the drawing, a guide rail12is formed in a width-directional middle area of an upper surface of the support base11so as to protrude upward and extend in the longitudinal direction. A moving table, that is, a moving block13is attached along the guide rail12so as to freely linearly reciprocate. In order to drive the moving block13, a driving source is housed inside the support base11. A drive rod14driven by the driving source is protruded from a distal end of the support base11as illustrated inFIG. 2A. A linear motor15having the drive rod14as a movable member is used as the driving source, and the linear motor15has a magnet16attached to the drive rod14and a coil17that is housed inside the support base11so as to surround the magnet16as illustrated inFIGS. 4 and 5.

A connection block18is fixed to the distal end of the drive rod14by a screw member19, and the connection block18is also fixed to a distal end of the moving block13by a screw member19a. The drive rod14is connected to the distal end of the moving block13, that is, one end thereof, and the other end opposite to the distal end serves as a base end. An electric power supply block20is attached to a base end surface of the support base11by a screw member19b, and a non-illustrated signal cable for supplying a drive signal to the coil17of the linear motor is connected to the electric power supply block20.

As illustrated inFIGS. 3 to 5, ball rolling grooves21aand21beach of which has an almost semi-circular cross-sectional shape are provided on both side surfaces12aand12bof the guide rail12over the whole length of the guide rail12as a first rolling groove. As illustrated inFIG. 6, a guide groove22to which the guide rail12is inserted is provided to the width-directional middle area of an inner surface of the moving block13over the whole length. When the moving block13is attached to the support base11, the guide rail12is inserted into the guide groove22so that the both side surfaces12aand12bof the guide rail12face both side surfaces22aand22bof the guide groove22, respectively.

On an inner side surface of the guide groove22at the base end of the moving block13, ball rolling grooves23aand23beach of which has an almost semi-circular cross-sectional shape are provided as a second rolling groove. A ball rolling path24ais formed of the ball rolling grooves21aand23afacing each other, and a ball rolling path24bis formed of the ball rolling grooves21band23bfacing each other.

Return holes, that is, ball circulation holes25aand25bare formed on the base end of the moving block13, and the ball circulation holes25aand25bare in parallel with the ball rolling paths24aand24b, respectively. A looped infinite circulation path is formed of a pair of the ball rolling path24aand the ball circulation hole25a, and a circulation path is similarly formed of a pair of the ball rolling path24band the ball circulation hole25b. A lot of balls26are housed in each circulation path. The ball circulation holes25aand25bare formed in parallel with the ball rolling paths24aand24bon a horizontal plane along the surface of the guide rail12, respectively.

By providing the guide rail12integrally on the support base11and providing the guide groove22into which the guide rail12is inserted on the inner surface of the moving block13, the moving block13is attached to the guide rail12so as to straddle the guide rail12. The ball circulation holes25aand25bare formed in parallel with the ball rolling paths24aand24bon the horizontal plane along the surface of the guide rail12, respectively. In addition, as illustrated inFIGS. 4 and 5, the linear motor15is housed so as to protrude from the support base11into the guide rail12. In this manner, a total thickness of the support base11and the moving block13can be reduced, so that a height of the linear-reciprocating device10in an up-and-down direction inFIGS. 4 and 5can be reduced.

As illustrated inFIG. 3, to the base end surface of the moving block13, a return lid member27athat communicates between the ball rolling path24aand the ball circulation hole25aand a return lid member27bthat communicates between the ball rolling path24band the ball circulation hole25bare attached. On the base end side of the moving block13, the return lid member27acommunicates between the ball rolling path24aand the ball circulation hole25a, and the return lid member27bcommunicates between the ball rolling path24band the ball circulation hole25b. As illustrated inFIG. 3, a circular protrusion28is provided to abutment surfaces of the return lid members27aand27b, respectively, and a fit hole29with which the protrusion28is fitted is provided to the base end surface of the moving block13. Each of the return lid members27aand27bis fastened to the moving block13by a screw member30screwed with a female screw that is provided to the moving block13so as to be coaxial with the fit hole29.

Attachment concave portions31aand31bare provided to the inner surface of the moving block13so as to be positioned in a longitudinal-directional middle area. To the attachment concave portions31aand31b, the return blocks32aand32bare provided, respectively. The return block32acommunicates between the ball rolling path24aand the ball circulation hole25ain the longitudinal-directional middle area of the moving block13, and the return block32bcommunicates between the ball rolling path24band the ball circulation hole25bin the longitudinal-directional middle area of the moving block13. In order to fix each of the return blocks32band32bto the moving block13, a screw member33screwed into a screw hole formed on the moving block13is attached to an attachment hole34provided to the return blocks32band32b.

When the moving block13linearly reciprocates, the moving block13moves along the guide rail12via a lot of balls26, and therefore, a rolling resistance applied to the moving block13is reduced, and the moving block13can be reciprocated smoothly with a small power. When the moving block13is driven, the balls26are circulated inside the looped continuous circulation path. The ball rolling paths24aand24bare provided on the base end side of the moving block13, and the balls26do not fall off the inside of the circulation path even if the distal end of the moving block13protrudes from the distal end of the guide rail12as illustrated inFIG. 2.

In this manner, even if the moving block13moves to a position at which the moving block13protrudes from the guide rail12of the support base11, the balls26can be interposed between the moving block13and the guide rail12. That is, even if the drive rod14protruding from the distal end surface of the support base11is connected to the distal end of the moving block13, the moving block13can be driven by the drive rod14. In order to restrict a moving-forward limitation position of the moving block13, a stopper35is attached to the distal end surface of the support base11as illustrated inFIG. 3.

While each of the support base11and the moving block13is made of a metal material, each of the return lid members27aand27band the return blocks32aand32bis made of a resin material. As illustrated inFIG. 6, the return lid members27aand27bare provided integrally to both ends of a first connecting portion36so as to protrude from the first connecting portion36. A guide groove37into which the guide rail12is inserted is formed of the return lid members27aand27band the first connecting portion36. Similarly, the return blocks32aand32bare provided integrally to both ends of a second connecting portion38so as to protrude from the second connecting portion38. A guide groove39into which the guide rail12is inserted is formed of the return blocks32aand32band the second connecting portion38. On the inner surface of the moving block13, an attachment groove to which the second connecting portion38is attached is provided so as to be continuous from the attachment concave portions31aand31b.

As illustrated inFIG. 8, guide fit holes41aand41beach having a semi-circular cross-sectional surface are formed on the return lid members27aand27b, and first return grooves42aand42bopened to the guide fit holes41aand41bare also formed on the return lid members27aand27b, respectively. Each of the first return grooves42aand42bhas an almost semi-circular cross-sectional surface, and extends in the longitudinal direction as a semi-circular shape. Each of return guides43aand43beach of which has an almost semi-circular cross-sectional surface is fitted to the guide fit holes41aand41b, and the return guides43aand43bare provided with second return grooves45aand45bwhich form base-end-side ball return paths44aand44btogether with the return grooves42aand42b, respectively. As similar to the return grooves42aand42b, each of the second return grooves45aand45bhas an almost semi-circular cross-sectional surface, and extends in the longitudinal direction as a semi-circular shape.

In order to fix the return guides43aand43bto the return lid members27aand27b, attachment holes47aand47bto which pins46are attached are provided to the return guides43aand43b, and fit holes48aand48bto which the pins46are attached are provided ti the return lid members27aand27bas illustrated inFIG. 6, respectively.

Similarly as illustrated inFIG. 10, guide fit holes51aand51beach of which has a semi-circular cross-sectional surface are formed on the return blocks32aand32b, and return grooves52aand52bopened to the guide fit holes51aand51bare also provided to the return blocks32aand32b, respectively. Each of the return grooves52aand52bhas an almost semi-circular cross-sectional surface, and extends in the longitudinal direction as a semi-circular shape. Return guides53aand53beach having an almost semi-circular cross-sectional surface are fitted to the guide fit holes51aand51b, and return grooves55aand55bfor forming middle-side ball return paths54aand54btogether with the return grooves52aand52bare provided to the return guides53aand53b, respectively. As similar to the return grooves52aand52b, each of the return grooves55aand55bhas an almost semi-circular cross-sectional surface, and extends in the longitudinal direction as a semi-circular shape.

In order to fix the return guides53aand53bto the return blocks32aand32b, respectively, attachment holes57aand57bto which a pin56is attached are provided to the return guides53aand53b, and, fit holes58aand58bto which the pin56is attached are provided to the return blocks32aand32bas illustrated inFIG. 10, respectively.

The return guides43aand43bare fixed to the return lid members27aand27bby using the pin46. However, the return guides43aand43bmay be fixed to the return lid members27aand27bby using a snap fit manner, welding, or bonding, or may be fixed to the guide fit holes41aand41bby using a press fit manner. As similar to the return guides43aand43b, the return guides53aand53bmay be fixed to the return blocks32aand32b.

As illustrated inFIGS. 1 and 2, a plurality of screw holes61are provided outside the guide rail12in a width direction, the screw holes61each being screwed with a screw member for fixing the support base11to a not-illustrated board, and screw holes62are also provided on both left and right side surfaces. A plurality of screw holes63and a plurality of positioning holes64are provided to the moving block13, the screw holes63to which a member to be transported such as a jig and tool arranged on an outer surface of the moving block13is attached, and the positioning holes64which positions the member to be transported.

To one linear-reciprocating device10, four return guides43a,43b,53a, and53bare attached. These return guides have the same shape as each other, so that any return guide can be mounted on the return lid members27aand27band the return blocks32aand32b. In this manner, components can be easily managed in the assembly of the linear-reciprocating device10.

As described above, since two return lid members27aand27bare connected integrally to each other by the first connecting portion36, both return lid members27aand27bcan be simultaneously attached to the moving block13by one attachment operation. Similarly, since two return blocks32aand32bare connected integrally to each other by the second connecting portion38, both return blocks32aand32bcan be simultaneously attached to the moving block13by one attachment operation. If the return lid members27aand27bare separation forms, each of them is separately attached to the moving block13. Similarly, if the return blocks32aand32bare separation forms, each of them is separately attached to the moving block13.

FIG. 11is a perspective view illustrating the return lid members27aand27bas a modification example,FIG. 12is a perspective view of the return lid members ofFIG. 11as viewed from an opposite side,FIG. 13is a perspective view of the return blocks32aand32bas a modification example, andFIG. 14is a perspective view of the return blocks ofFIG. 13as viewed from an opposite side. In these drawings, common components with the above-described components are denoted by the same reference symbols.

The return lid members27aand27billustrated inFIGS. 11 and 12are separation forms, and therefore, each of them is separately attached to the moving block13. Similarly, the return blocks32aand32billustrated inFIGS. 13 and 14are also separation forms, and therefore, each of them is separately attached to the moving block13.

FIG. 15is a perspective view illustrating a modification example of the moving block13. Although the guide groove22is provided to this moving block13on a base end side, and the guide groove22is not provided thereto on a distal end side. The return lid members27aand27billustrated inFIG. 7or11are attached to the base end surface of the moving block13, and the return blocks32aand32billustrated inFIG. 9or13are attached to the moving block13so as to be abutted onto an abutment surface65provided in a longitudinal-directional middle area of the moving block13.

FIG. 16is a cross-sectional view illustrating a modification example of the linear-reciprocating device10, andFIG. 16illustrates the same part asFIG. 15.

As illustrated inFIG. 16, in this linear-reciprocating device10, two ball rolling grooves21aand21aare provided to a side surface12aof the guide rail12so as to vertically interpose a gap therebetween, and two ball rolling grooves21band21bare provided to a side surface12bof the guide rail12so as to vertically interpose a gap therebetween. Two vertically-arranged ball rolling grooves23aand23aare provided to a side surface22aof the guide groove22so as to face the two ball rolling grooves21aand21a, and two vertically-arranged ball rolling grooves23band23bare provided to a side surface22bof the guide groove22so as to face the two ball rolling grooves21band21b.

FIG. 17is a cross-sectional view illustrating a modification example of the driving source of the linear-reciprocating device10. While the linear motor15is housed as the driving source inside the support base11in the above-described linear-reciprocating device10, a pneumatic cylinder70is housed as the driving source inside the support base11in the linear-reciprocating device10illustrated inFIG. 17.

A cylinder hole71is provided into the support base11, and a piston72is attached to the base end of the drive rod14. A cover73is attached to the base end of the support base11, and a cover74thorough which the drive rod14penetrates is attached to the distal end of the support base11. The cylinder hole71is partitioned by the piston72into a pneumatic chamber71afor moving the rod forward and a pneumatic chamber71bfor moving the rod backward, and compressed air is supplied from a not-illustrated inlet/outlet port to each of the pneumatic chambers71aand71b. By supplying the compressed air to the pneumatic chamber71a, the moving block13is moved forward from a moving-backward limit position illustrated inFIG. 17toward a moving-forward limit position. On the other hand, by supplying the compressed air to the pneumatic chamber71b, the moving block13is moved backward from the moving-forward limit position toward the moving-backward limit position.

As described above, the moving block13is driven to be reciprocated by the drive rod14between the moving-backward limit position illustrated inFIG. 1and the moving-forward limit position illustrated inFIG. 2. In this reciprocation, the moving block13is supported via the balls26circulating between the guide rail12and the moving block13, and therefore, can be smoothly reciprocated.

The balls26are circulated through the ball rolling paths24aand24band the ball circulation holes25aand25bprovided on the base end side of the moving block13, and therefore, the moving block13can be moved to a position at which the moving block13is protruded from the distal end of the guide rail12. On the other hand, when a slit for connecting a drive member such as a slider with the moving block13is conventionally provided to the support base11, a height of the linear-reciprocating device10increases. However, since the moving block13is driven by the drive rod14protruded from the distal end surface of the support base11as illustrated, a small linear-reciprocating device10having a small height can be provided even when the moving block13is driven by the driving source provided to the support base11.

If the guide rail12is attached to the support base11so that the support base11and the guide rail12are member separately formed from each other, and if the driving source is provided inside the support base11, a large height of the linear-reciprocating device including the support base11and the guide rail12cannot be avoided. On the other hand, if the support base11and the guide rail12are integrally formed with each other so that the guide rail12is inserted into the guide groove22formed on the inner surface of the moving block13and so that the moving block13is attached to the guide rails12to straddle between the guide rails12, the driving source can be embedded even inside the guide rail12, which results in the small height of the linear-reciprocating device. In this manner, the linear-reciprocating device10can be downsized.

The present invention is not limited to the above-described embodiment and various modifications can be made within the scope of the present invention. For example, in the above-described linear-reciprocating device10, the moving block13is driven by the driving source provided inside the support base11. However, other aspect that the moving block13is driven by the driving source arranged outside the support base11may be adopted.

INDUSTRIAL APPLICABILITY

This linear-reciprocating device is applied to move an object to be transported such as a workpiece or a jig and a tool.