JP5352278B2 - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the linear actuator which suppresses an imbalanced load imparted on a linear guide part when a slide table reciprocates and which is thinner as compared with a linear actuator having a slide table overlaid on a cylinder device. <P>SOLUTION: A linear actuator 11 is equipped with a cylinder device 13 having a piston rod 12 and a slide table 17 arranged so as to be aligned with the cylinder device 13 along an axial direction of a piston rod 12. The piston rod 12 is coupled to the slide table 17 through the medium of a first and second floating members 39, 40. Reciprocation of the slide table 17 is guided by a pair of linear guides 33 and a pair of guide rails 32 respectively engaged with the linear guides 33. The piston rod 12 is in parallel with the linear guide 33 and is disposed so as to make distances with a pair of linear guides 33 equal to each other. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a linear actuator in which a slide table reciprocates by thrust from a piston rod of a cylinder device.

  For example, as a linear actuator that conveys jigs, workpieces, etc. at the production site of products, a slide table on which workpieces can be placed is placed on the side of the cylinder device body, and the slide table is linear due to the thrust of the cylinder device Are known to perform the reciprocating motion (see, for example, Patent Document 1). In the linear actuator described in Patent Document 1, a body in which a cylinder chamber is provided, a piston accommodated in a reciprocating manner in the cylinder chamber, a table disposed so as to overlap the body, and a table are reciprocated. And a guide that is movably supported. In this linear actuator, the rod that moves integrally with the piston is connected to the table via the tip block, and the guide is composed of a linear guide fixed to the lower surface of the table and a guide rail provided on the upper surface of the body. Has been.

Japanese Utility Model Publication No. 6-43302

  By the way, in the linear actuator described in Patent Document 1, the rod for transmitting the thrust to the tip block exists at a position shifted to one side in the left-right direction with respect to the linear guide. Therefore, when the thrust of the cylinder device is applied from the rod to the tip block to reciprocate the table, a moment acts on the linear guide, thereby applying a leftward or rightward eccentric load on the linear guide. Then, when an unbalanced load is applied to the linear guide, the life of the linear actuator is shortened, which is a problem. In addition, the linear actuator has a disadvantage that the entire thickness of the linear actuator is thick because the table is arranged on the body.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress an uneven load applied to the linear guide portion when the slide table reciprocates, and the slide table is arranged to overlap the cylinder device. It is to provide a linear actuator that is thinner than the linear actuator.

In order to achieve the above object, the invention according to claim 1 is a cylinder device having a piston rod movable in the axial direction, and reciprocating along the axial direction of the piston rod by a thrust from the piston rod. A linear actuator including a slide table, and a linear guide that guides the reciprocating motion of the slide table; and a connecting portion that connects the piston rod and the slide table. The piston rod is arranged on both sides, the slide table is arranged side by side in the cylinder device in the axial direction of the piston rod, and the piston rod is arranged in parallel with the linear guide part, The distance between the piston rod and one of the linear guides, and the front The distance between the piston rod and the other linear guide portion is equal, and the linear guide portion includes a linear guide provided on the slide table side and a guide rail that engages with the linear guide. , the axis of said piston rod, said guide rail and a vertical direction center of the linear guide engaging portion engaged, vertical position Ri same der engaging portion of the linear guide, the linear A plurality of ball bearings provided between a guide and the guide rail, wherein the plurality of ball bearings are arranged vertically on a side portion of the linear guide facing the guide rail, and the piston The axis of the rod and the center position in the vertical direction of the entire ball bearing disposed above and below are the same in the vertical direction, and the front A central position in the vertical direction of the entire ball bearing is located at an equal distance from the center of each of the ball bearings arranged above and below, and the connecting portion is a first floating fixed to the piston rod side. The gist includes a member and a second floating member that is fixed to the slide table side and engages with the first floating member in a state in which relative movement within a predetermined range is possible .

  In this invention, a thrust is given to a slide table via a connection part because a piston rod moves to an axial direction. Then, the slide table reciprocates while being guided by the linear guide portion. In this case, even if the piston rod that gives thrust and the linear guide portion are separated from each other, the distance between the piston rod and the linear guide portion is the same, so that the offset load applied to the linear guide portion can be reduced.

  Further, since the slide table and the cylinder device are arranged side by side along the axial direction of the piston rod, the entire linear actuator can be made thinner than a linear actuator in which the slide table is stacked on the cylinder device. it can.

  In this invention, the moment resulting from the displacement of the piston rod upward or downward relative to the linear guide does not act on the linear guide and the guide rail. As a result, it is possible to reduce the offset load applied upward or downward with respect to the linear guide portion.

The invention of claim 2 is the invention according to claim 1, the central portion in the axial direction of the piston rod before Symbol second floating member includes a central portion in the axial direction of the piston rod of the linear guide The gist is that they are arranged at the same position.

In the present invention, for example, when a work is placed on the slide table, the slide table is bent and the linear guide is tilted, the maximum tilt amount of the second floating member due to the influence can be reduced. In other words, even if the amount of bending of the slide table and the amount of inclination of the linear guide are the same, the second floating member is more in the axial direction of the piston rod than in the case where the second floating member is located at the same position as the end of the linear guide. The maximum inclination amount of the member can be reduced. As a result, it is possible to suppress friction between the first floating member and the second floating member due to the bending of the slide table and the inclination of the linear guide, thereby suppressing the wear of the first floating member and the second floating member. I can .

  According to the present invention, it is possible to suppress the uneven load applied to the linear guide portion when the slide table reciprocates, and to make the linear actuator thinner than a linear actuator in which the slide table is placed on the cylinder device. it can.

(A) is a partially broken plan view of the linear actuator, (b) is a side view of the linear actuator. The AA sectional view taken on the line of Fig.1 (a). The BB partial sectional view of FIG. (A) is sectional drawing of the linear actuator in another embodiment, (b) is a partial top view of the linear actuator in another embodiment.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. In the following, the front-rear direction is indicated by the arrow Y1 in FIGS. 1A and 1B, the left-right direction is indicated by the arrow Y2 in FIG. 1A, and the vertical direction is indicated by the arrow Y3 in FIG. .

  As shown in FIGS. 1A and 1B, the linear actuator 11 is connected to the cylinder device 13 via a cylinder device 13 having a piston rod 12 movable in the axial direction (front-rear direction) and a connecting block 14. A connected support plate 15 and a slide table 17 supported so as to be movable on the support plate 15 via a linear guide portion 16 are provided.

  As shown in FIG. 1A, the cylinder housing 18 of the cylinder device 13 is formed with a cylinder chamber 19 extending in the front-rear direction. The cylinder chamber 19 is partitioned by having one opening sealed with a rod cover 20 and the other opening sealed with a head cover 21. The head cover 21 is secured from the cylinder housing 18 by a C ring 22. Further, the rod cover 20 is prevented from being detached from the cylinder housing 18 by a retaining member (not shown). The cylinder chamber 19 accommodates a piston 23 that can move along the axial direction of the piston rod 12.

  A piston packing 24 is attached to the peripheral surface of the piston 23, and an annular magnet 25 is attached to a portion closer to the rod cover 20 than the piston packing 24. The magnet 25 is configured to be detectable by a position detection switch (not shown). The piston 23 partitions the cylinder chamber 19 into a first chamber 26 on the rod cover 20 side and a second chamber 27 on the head cover 21 side, and is coupled to the piston rod 12 so as to be movable together.

  The first chamber 26 communicates with a first supply / discharge port 28 having one end opened to the outside. The second chamber 27 communicates with a second supply / discharge port 29 having one end opened to the outside. An air supply means (not shown) is connected to the first supply / discharge port 28 and the second supply / discharge port 29 via a pipe (not shown). The piston rod 12 passes through the rod cover 20 and the connecting block 14 and is partially accommodated in the first chamber 26. A rod packing 30 that seals between the piston rod 12 and the rod cover 20 is provided on the inner peripheral surface of the rod cover 20. A support plate 15 having a rectangular shape in plan view is provided below the portion of the piston rod 12 extending from the cylinder housing 18.

  One end of the support plate 15 is coupled to the end of the cylinder housing 18 via the coupling block 14. The support plate 15 has a longitudinal direction parallel to the axial direction of the piston rod 12. That is, the support plate 15 is arranged in series with the cylinder device 13 along the axial direction of the piston rod 12.

  The slide table 17 provided on the support plate 15 is formed in a rectangular shape in plan view, and its upper surface 17a is configured as a mounting surface for mounting a workpiece. The slide table 17 reciprocates in the front-rear direction indicated by Y <b> 1 while being guided by the linear guide portion 16 to convey a workpiece (not shown) and is arranged in series with the cylinder device 13 along the axial direction of the piston rod 12. .

  The linear guide portion 16 is provided on a pair of guide rails 32 fastened to the upper surface 15 a of the support plate 15 by bolts 31 and a lower surface 17 b (see FIG. 2) of the slide table 17 and engages with the guide rails 32. The linear guide 33 is comprised. The pair of linear guides 33 are positioned so as to be sandwiched between the pair of guide rails 32 in the left-right direction, and are fastened to the lower surface 17b of the slide table 17 by bolts B. As shown in FIG. 2, a plurality of ball bearings 34 that engage with the guide rail 32 are provided on the side of the linear guide 33 that faces the guide rail 32. The plurality of ball bearings 34 are arranged vertically. The plurality of ball bearings 34 are provided so that the linear guide 33 slides smoothly with respect to the guide rail 32, and the entire plurality of ball bearings 34 constitute an engaging portion of the linear guide 33.

  The pair of guide rails 32 are provided on both the left and right sides of the support plate 15, and extend parallel to the axial direction of the piston rod 12 and over substantially the entire longitudinal direction of the support plate 15. The pair of guide rails 32 are aligned with the support plate 15 by protrusions 35 provided on the left and right sides of the support plate 15. The linear guide 33 extends so that the axial direction of the piston rod 12 is the longitudinal direction, and has a positional relationship parallel to the pair of guide rails 32.

  As the slide table 17 reciprocates, the ball bearing 34 rolls along the rolling groove 36 of the guide rail 32 and the rolling groove 37 of the linear guide 33 and circulates through the ball circulation hole 38. It has become. The ball bearing 34 mediates the rolling groove 36 and the ball circulation hole 38 via a ball return member (not shown).

  The slide table 17 is connected to the lower surface 17b of the tip 12a (see FIG. 3) of the piston rod 12 via the first floating member 39 and the second floating member 40. As shown in FIG. 3, both ends 39 a and 39 b of the first floating member 39 are formed in a flange shape, and are fastened to the piston rod 12 by bolts 41. The first floating member 39 is engaged with a substantially U-shaped second floating member 40.

  The second floating member 40 is fastened to the slide table 17 by a bolt 43 while a concave portion 42 opening downward is engaged with an intermediate portion 39 c of the first floating member 39. In the state where the second floating member 40 is fastened to the slide table 17, the central portion P <b> 1 of the second floating member 40 and the central portion P <b> 2 of the linear guide 33 are at the same position in the axial direction of the piston rod 12. Note that the central portion P <b> 1 of the second floating member 40 is equidistant from the axis of each bolt 43. The central portion P2 of the linear guide 33 means the center in the axial direction of the piston rod 12, and is spaced equidistant from both ends of the linear guide 33 in the axial direction of the piston rod 12. A predetermined clearance exists between the second floating member 40 and both end portions 39a and 39b of the first floating member 39 and between the second floating member 40 and the intermediate portion 39c of the first floating member 39. doing. Therefore, the first floating member 39 and the second floating member 40 are configured to be relatively movable within a predetermined range in the front-rear direction and the left-right direction, and also constitute a connecting portion that connects the piston rod 12 and the slide table 17. .

  In a state where the piston rod 12 is connected to the slide table 17 by the first floating member 39 and the second floating member 40, the tip end portion 12 a is positioned between the pair of linear guides 33, and below the slide table 17. Is located. As shown in FIG. 2, the axis L of the piston rod 12 and the central position Q in the vertical direction of the entire ball bearing 34 arranged in the vertical direction are the same in the vertical direction. The central position Q in the vertical direction of the entire ball bearing 34 is at a position spaced equidistant from the center of each of the ball bearings 34 arranged vertically. The piston rod 12 is parallel to the pair of linear guide portions 16 and is equidistantly spaced. That is, as shown in FIG. 3, the distance T1 from the axis L of the piston rod 12 to the linear guide portion 16 located on the right side of the piston rod 12 (the central position Q of the entire ball bearing 34 on the right side of the piston rod 12) The distance T2 from the axis L of the piston rod 12 to the linear guide 33 located at the left side of the piston rod 12 (the central position Q of the entire ball bearing 34 on the left side of the piston rod 12) is equal. Therefore, the position of the piston rod 12 is set so that the moments acting on the pair of linear guide portions 16 by the thrust of the piston rod 12 are balanced with each other.

Next, the operation of the linear actuator 11 in this embodiment will be described.
In the linear actuator 11, when the air in the first chamber 26 is discharged via the first supply / discharge port 28 and the air is supplied to the second chamber 27 via the second supply / discharge port 29, the piston 23 And the piston rod 12 moves forward. Then, the piston rod 12 pushes the first and second floating members 39 and 40 forward, whereby the slide table 17 moves forward along the axial direction of the piston rod 12 while being guided. In the linear actuator 11, when air is supplied to the first chamber 26 via the first supply / discharge port 28 and air is discharged from the second chamber 27 via the second supply / discharge port 29, the piston 23 and the piston rod 12 move backward. Then, the piston rod 12 pulls the first and second floating members 39 and 40 rearward, whereby the slide table 17 moves rearward along the axial direction of the piston rod 12 while being guided.

  When a thrust is applied from the piston rod 12 and the slide table 17 reciprocates, a distance T1 from the piston rod 12 to one linear guide portion 16 (the central position Q of one ball bearing 34 as a whole), and the piston rod Since the distance T2 from 12 to the other linear guide portion 16 (the central position Q of the other ball bearing 34 as a whole) is equal to each other, the moments acting on the left and right linear guide portions 16 are balanced. . Therefore, no extra moment is generated in each linear guide portion 16, and when thrust is applied from the piston rod 12, the slide table 17 reciprocates in a state in which a lateral load is not applied to the pair of linear guide portions 16. Move.

  The piston rod 12 and the center position Q of the ball bearings 34 arranged vertically are the same in the vertical direction, and the piston rod 12 is relative to the whole of the plurality of ball bearings 34 arranged vertically. There is no vertical displacement. Therefore, when a thrust is applied from the piston rod 12 to reciprocate the slide table 17, an extra moment due to the piston rod 12 being displaced upward or downward with respect to the engaging portion of the linear guide 33. Does not occur in the linear guide 33 and the guide rail 32. Therefore, the slide table 17 reciprocates in a state where no upward or downward load is applied to the pair of linear guides 33. In the present embodiment, when a thrust is applied from the piston rod 12 and the slide table 17 reciprocates, an extra load other than the thrust along the axial direction of the piston rod 12 does not act on the linear guide portion 16 as much as possible. It has become.

  Further, when the slide table 17 conveys a work, the work is placed on the upper surface 17 a of the slide table 17. In this case, the slide table 17 is bent by receiving a load from the workpiece, and the linear guide 33 may be tilted as the slide table 17 is bent. In this case, the second floating member 40 is inclined, but the center portion P1 of the second floating member 40 is located at the center portion P2 of the linear guide 33 in the axial direction of the piston rod 12, and therefore the second floating member 40 Is less affected by the inclination of the linear guide 33. That is, when the second floating member 40 is provided so as to coincide with the end of the linear guide 33 in the axial direction of the piston rod 12 even if the deflection amount of the slide table 17 and the inclination amount of the linear guide 33 are the same. In comparison, the amount of inclination of the second floating member 40 can be kept small. Therefore, friction between the first floating member 39 and the second floating member 40 caused by the bending of the slide table 17 and the inclination of the linear guide 33 can be suppressed. As a result, the first floating member 39 and the second floating member 40 Wear can be suppressed.

According to this embodiment, the following effects can be obtained.
(1) The linear actuator 11 includes a cylinder device 13 having a piston rod 12 and a linear guide portion 16 that guides the reciprocating motion of the slide table 17. The piston rod 12 is disposed so as to be parallel to the linear guide portion 16 and to have the same distance from the linear guide portion 16. Therefore, when the thrust is applied from the piston rod 12 and the slide table 17 reciprocates, the uneven load applied to the linear guide portion 16 can be reduced.

  (2) The slide table 17 is arranged in the cylinder device 13 along the axial direction of the piston rod 12. Therefore, the entire linear actuator 11 can be made thinner than the linear actuator 11 in which the slide table 17 is overlaid on the cylinder device 13.

  (3) The axis L of the piston rod 12 and the central position Q of the entire ball bearing 34 disposed vertically are the same position in the vertical direction. Therefore, no extra moment is generated in the linear guide 33 and the guide rail 32 due to the piston rod 12 being displaced upward or downward with respect to the plurality of ball bearings 34 arranged vertically. As a result, the offset load applied upward or downward with respect to the linear guide 33 can be reduced.

  (4) The piston rod 12 and the slide table 17 are connected by the first floating member 39 and the second floating member 40. And the 1st floating member 39 and the 2nd floating member 40 are engaged in the state which can be relatively moved only by the predetermined range. The central portion P1 of the second floating member 40 is located at the same position as the central portion P2 of the linear guide 33 in the axial direction of the piston rod 12. Therefore, friction between the first floating member 39 and the second floating member 40 due to the bending of the slide table 17 and the inclination of the linear guide 33 can be suppressed, and the first floating member 39 and the second floating member 40 are worn. Can be suppressed.

  (5) Even if the inclination amount of the linear guide 33 is the same, the central portion P1 of the second floating member 40 is at the same position in the axial direction of the piston rod 12 and the end of the linear guide 33 in the axial direction of the piston rod 12. Compared with the case where it is located, the inclination amount of the 2nd floating member 40 can be restrained small. Therefore, the twisting between the first floating member 39 and the second floating member 40 can be suppressed, and consequently the malfunction of the linear actuator 11 can be suppressed.

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ The configuration of the linear guide portion 16 may be changed. For example, as shown in FIG. 4A, a linear guide 33 whose cross-sectional shape orthogonal to the extending direction is substantially U-shaped (channel shape) is formed, and the concave portion 42 of the linear guide 33 is connected to the guide rail 32. You may make it engage. In this case, the ball bearing 34 is disposed on the inner wall surface of the recess 42 facing the guide rail 32. The ball bearing 34 may be configured to roll between the guide rail 32 and the linear guide 33, and the slide table 17 may be configured to reciprocate while being guided by the linear guide portion 16. The vertical center of the engaging portion of the linear guide 33 corresponds to the ball center of the ball bearing 34.

  O The configuration is not limited to the configuration in which the plurality of ball bearings 34 circulate. For example, the ball circulation hole 38 and the ball return member may be omitted, and the plurality of ball bearings 34 may only roll without being circulated.

  The linear guide portion 16 may be configured to guide the reciprocating motion of the slide table 17, and the ball bearing 34 interposed between the guide rail 32 and the linear guide 33 may be omitted. For example, the linear guide 33 may be formed so that the cross-sectional shape orthogonal to the extending direction is substantially U-shaped (channel shape), and the concave portion of the linear guide 33 may be engaged with the guide rail 32. . In this case, the concave portion of the linear guide 33 that engages with the guide rail 32 is configured as an engaging portion of the linear guide 33.

  If the piston rod 12 is disposed at a position where the distance between the piston rod 12 and the linear guide portion 16 is equal, the portion of the slide table 17 that connects the piston rod 12 may be changed. For example, as shown in FIG. 4 (b), the second floating member 40 is brought into contact with the side surface 17c on the rear side (cylinder device 13 side) of the slide table 17, and in this state, the rear of the slide table 17 with the bolt 50 The second floating member 40 may be fixed to the side surface 17c. If comprised in this way, the piston rod 12 and the slide table 17 can be connected, and the second floating member 40 is not disposed so as to be sandwiched between the support plate 15 and the slide table 17. The thickness from the bottom surface of the support plate 15 to the upper surface 17a of the slide table 17 can be reduced.

  (Circle) You may change the positional relationship in the up-down direction of the linear guide part 16 and the piston rod 12. FIG. For example, if the distance between the piston rod 12 and the linear guide portion 16 is equal and the piston rod 12 is parallel to the linear guide portion 16, the entire ball bearing 34 in which the axis L of the piston rod 12 is arranged vertically is provided. The piston rod 12 and the slide table 17 may be connected in a state of being shifted downward with respect to the central position Q.

  The number of guide rails 32 and linear guides 33 may be increased. For example, a linear guide portion including a guide rail and a linear guide may be further provided on both the left and right sides of the guide rail 32 and the linear guide 33, and the linear guide portion may be disposed so as to sandwich the piston rod 12 therebetween. In this case, the distance between the piston rod 12 and the linear guide portions on the left and right sides different from the linear guide portion 16 may be the same.

  ○ Instead of providing the first floating member 39, which is a separate member from the piston rod 12, the tip 12a of the piston rod 12 may be formed in the same shape as the first floating member 39, and the first floating member 39 may be omitted. Good. In this case, although it takes time to manufacture the cylinder device 13, the work of assembling the first floating member 39 to the piston rod 12 can be omitted.

  The cylinder device 13 may be constituted by a fluid pressure cylinder driven by a gas other than air or a liquid such as oil.

  L ... axis, 11 ... linear actuator, 12 ... piston rod, 13 ... cylinder device, 16 ... linear guide part, 17 ... slide table, 32 ... guide rail, 33 ... linear guide, 39 ... first floating member, 40 ... first 2 floating members.

Claims (2)

A linear actuator comprising a cylinder device having a piston rod movable in the axial direction, and a slide table that reciprocates along the axial direction of the piston rod by thrust from the piston rod,
A linear guide for guiding the reciprocation of the slide table;
A connecting portion for connecting the piston rod and the slide table,
The linear guide portion is disposed on both sides with the piston rod in between,
The slide table is arranged side by side with the cylinder device in the axial direction of the piston rod, and the piston rod is arranged in parallel with the linear guide part,
The distance between the piston rod and one of the linear guide portions and the distance between the piston rod and the other linear guide portion are equal,
The linear guide portion includes a linear guide provided on the slide table side, and a guide rail that engages with the linear guide, and an axis of the piston rod and an engagement of the linear guide that engages with the guide rail. the vertical center of the engagement portion, Ri vertical position is the same der,
The engaging portion of the linear guide is a plurality of ball bearings provided between the linear guide and the guide rail, and the plurality of ball bearings are on the side of the linear guide that faces the guide rail. Are arranged up and down in the section,
The axis of the piston rod and the central position in the vertical direction of the entire ball bearing disposed above and below are the same in the vertical direction, and the central position in the vertical direction of the entire ball bearing is disposed vertically. The ball bearings are at equidistant positions with respect to the respective centers;
The connecting portion is fixed to the first floating member fixed to the piston rod side and is engaged to the first floating member while being movable relative to the first floating member within a predetermined range. A linear actuator comprising a second floating member . Central unit, the linear guide of the piston linear actuator according to claim 1 which is co-located with the central portion in the axial direction of the rod in the axial direction of the piston rod before Symbol second floating member.

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