Connection structure and parallel connection rod robot

Abstract

A connection structure (10) that connects two links (5a, 5b) to each other, the two links having long axes (C) and operating in parallel with a gap therebetween, the connection structure (10) being provided with: bushings (20a, 20b) that are attached to the respective links so as to be rotatable about an axis (D) orthogonal to a plane including the two long axes, and bushings (20a, 20b) that are attached to the respective links so as to be able to rotate about an axis (D) orthogonal to a plane including the two long axes; a force applying mechanism (30) which is erected between the bushings of the two connecting rods and applies elastic restoring force to the two bushings in the direction in which the two bushings approach each other; and a connection member (50) that has two attachment holes capable of passing through each of the bushes in the axial direction, and that limits the distance between the bushes to a predetermined distance or less, the bushes being provided with claw sections that protrude radially outward at a part of the circumferential direction of the ends in the axial direction. Each of the mounting holes is formed so as to allow penetration of each of the bushings only at a predetermined mounting phase around the axis that coincides with the claw portion of each of the bushings, and the phase around the axis of each of the bushings is restricted to a phase that does not coincide with the mounting phase by the elastic restoring force.

Description

Technical Field

[0001] The invention relates to a connection structure and a parallel-link robot. Background Art

[0002] A spring device is known that connects two parallel links of a robot using a parallel mechanism (for example, see Patent Document 1). The spring device pulls the links toward each other and restricts the distance between the two links from expanding beyond a predetermined distance.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-097571 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The parts connected to the two connecting rods in order to limit the distance between the two connecting rods are sometimes easy to fall off when the connecting rods are actuated. In order to prevent this from falling off, when the parts connected to the connecting rods are assembled using bolts etc., tools are required during assembly and disassembly operations.

[0008] Therefore, it is desired to prevent the member that regulates the distance between the two links from falling off and to facilitate assembly and disassembly without using a tool.

[0009] Solutions for solving problems

[0010] One scheme of the present invention is a connection structure, which connects two connecting rods with each other, wherein the two connecting rods have a long axis and move in parallel with a gap, and the connection structure comprises: a bushing, which is mounted on each of the connecting rods in a manner that allows it to rotate around an axis orthogonal to a plane containing the two long axes; a force-applying mechanism, which is mounted between the bushings of the two connecting rods and applies an elastic restoring force to the two bushings in a direction toward each other; and a connecting component, which has two mounting holes that can penetrate each of the bushings along the axial direction and limit the distance between the bushings to less than a predetermined distance, the bushing having a claw portion that protrudes radially outward at a portion of the circumference of the end portion in the axial direction, and each of the mounting holes is formed into the following shape: each of the bushings is allowed to penetrate only at a predetermined installation phase around the axis that is consistent with the claw portion of each bushing, and each phase of each bushing around the axis is limited to a phase that is inconsistent with the installation phase by the elastic restoring force. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic front view showing a parallel link robot according to an embodiment of the present invention.

[0012] Figure 2 Yes means Figure 1 A schematic front view of the installation state of the force application mechanism of the connection structure of a pair of links of the parallel link robot.

[0013] Figure 3 Yes means Figure 1 A cross-sectional view showing the shape of a mounting pin and a pair of bushings included in one link of a parallel link robot.

[0014] Figure 4 It means in Figure 3 A side view of the shape of a bushing of the connecting structure shown in FIG.

[0015] Figure 5 It means in Figure 4 The shape of the bushing is shown in the front view.

[0016] Figure 6 It means in Figure 3 A side view of another bushing shape of the connection structure shown in FIG.

[0017] Figure 7 It means in Figure 6 The shape of the bushing is shown in the front view.

[0018] Figure 8 It means in Figure 2 A perspective view of the shape of the hook of the connecting structure shown in FIG.

[0019] Fig. 9 It means in Figure 2 A front view of the shape of the connecting component of the connecting structure shown in FIG.

[0020] Fig.10 It is explained in Figure 2 A diagram showing the order of installation of connection components in the connection structure shown in FIG.

[0021] Fig.11 It is explained in Figure 2 A diagram showing the order of installation of connection components in the connection structure shown in FIG.

[0022] Fig.12 It means in Figure 2 Schematic front view of the installation state of the connection components in the connection structure shown in .

[0023] Fig.13 It means in Figure 2 A schematic front view of the shape of the urging mechanism in the first modified example of the connection structure shown in FIG.

[0024] Fig.14 It means in Figure 2 A schematic diagram of the shape of one bushing in a second variation of the connection structure shown in FIG. DETAILED DESCRIPTION

[0025] Hereinafter, a connection structure 10 and a parallel link robot 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0026] like Figure 1 As shown, the parallel linkage robot 1 of the present embodiment includes a base portion 2 that is fixed, for example, by being suspended from a ceiling. In addition, the parallel linkage robot 1 includes a movable portion 3 that is arranged at intervals below the base portion 2. Furthermore, the parallel linkage robot 1 includes three arms 4 that are supported so as to be rotatable around three horizontal axes A relative to the base portion 2. In addition, in the parallel linkage robot 1, each arm 4 includes two pairs of mutually parallel links 5a, 5b that connect each arm 4 and the movable portion 3. Furthermore, the parallel linkage robot 1 includes connection structures 10, 10' that are mounted between each pair of links 5a, 5b.

[0027] The base 2 includes three servomotors 6 for respectively driving the three arms 4. The servomotors 6 are arranged at equal intervals in the circumferential direction around an axis B that passes through the center of the base 2 and extends in the vertical direction.

[0028] The servomotors 6 have rotary drive shafts (not shown) that rotate about a horizontal axis A, respectively.

[0029] The base end of each arm 4 is connected to the rotation drive shaft of the corresponding servo motor 6, and each arm 4 can rotate around the axis A relative to the base 2. Figure 2 As shown, the parallel link robot 1 includes a pair of ball joints 7a and 7b connecting the distal ends of the arms 4 and the links 5a and 5b. Each of the ball joints 7a and 7b includes ball studs 8a and 8b and sockets 9a and 9b.

[0030] The ball studs 8a and 8b are installed in the direction of the axis A across the front end of each arm 4 (see Figure 1 ) on both outer sides.

[0031] Each pair of link rods 5a, 5b has sockets 9a, 9b at one end in the direction of the long axis C. The sockets 9a, 9b are respectively fitted with ball studs 8a, 8b at the front ends of the corresponding arms 4 in a manner sandwiched from both sides in the direction of the axis A.

[0032] In addition, if Figure 2 as well as Figure 3As shown, each socket 9a, 9b is provided with a mounting pin 29 protruding in a direction perpendicular to the long axis C. The mounting pin 29 is pressed into a pin hole 9h penetrating the sockets 9a, 9b in a direction perpendicular to the long axis C, and protrudes to both sides across the long axis C. In addition, the mounting pin 29 is pressed into one side of the pin hole 9h until it abuts against a flange-shaped positioning portion 29p provided at a midway position in the longitudinal direction. As a result, the protruding amounts of the mounting pin 29 protruding to both sides of the outer peripheral surface of the sockets 9a, 9b are aligned with each other at the same length. In addition, the mounting pin 29, in the assembled state, extends along an axis D perpendicular to a plane including the long axis C of the two connecting rods 5a, 5b.

[0033] In addition, each connecting rod 5a, 5b is provided with a socket 9a', 9b' similar to the one end at the other end in the direction of the long axis C. The socket 9a', 9b' constitutes a ball joint 7a', 7b' together with the ball stud 8a', 8b' provided in the movable part 3. The socket 9a', 9b' is provided with a pin hole 9h and a mounting pin 29 pressed into the pin hole 9h, similar to the socket 9a, 9b.

[0034] The movable part 3 is provided with a pair of parallel flat plate-shaped mounting parts 3w protruding radially outward from the outer peripheral surface at the position corresponding to each pair of connecting rods 5a, 5b. Ball studs 8a', 8b' are mounted on the outside of each pair of mounting parts 3w. The sockets 9a', 9b' at the other ends of each connecting rod 5a, 5b are respectively inserted into the ball studs 8a', 8b' in a form of being clamped from both outsides in the direction of the axis A.

[0035] Hereinafter, the connection structures 10 and 10 ′ according to the present embodiment will be described.

[0036] In this embodiment, the three pairs of connecting rods 5a, 5b and the three upper and lower connecting structures 10, 10' have the same structure. Therefore, in the following, the structure of a pair of connecting rods 5a, 5b and one connecting structure 10 is described as an example.

[0037] like Figure 2 as well as Figure 3 As shown in FIG. 1 , the connection structure 10 includes bushings 20a and 20b mounted on the sockets 9a and 9b. Figure 2 As shown, the connection structure 10 includes a biasing mechanism 30 and a connection member 50 which are provided between the sockets 9a and 9b and connect the two sockets.

[0038] The bushings 20a and 20b are manufactured by, for example, injection molding a resin material such as silicone resin. Figures 4 to 7 As shown, the bushings 20 a and 20 b each have a cylindrical shape having a hollow hole 21 .

[0039] The hollow hole 21 has a circular cross section that allows the mounting pin 29 to be rotatably fitted. In addition, the hollow hole 21 of the bushing 20a is provided with an escape groove portion corresponding to the positioning portion 29p provided on the mounting pin 29. Thus, the combination when the bushings 20a and 20b are mounted on both ends of the mounting pin 29 is uniquely determined.

[0040] The bushings 20a and 20b respectively include first tube portions 22a and 22b on one side in the axial direction and second tube portions 23 on the other side in the axial direction. The first tube portions 22a and 22b have claws (claw portions) 24a and 24b at the axial front end of the cylindrical portion, in a form in which a part of the circumference protrudes radially outward.

[0041] The counter claws 24a and 24b will be described later.

[0042] The second cylinder 23 has an outer shape larger than the outer diameter of the first cylinders 22a and 22b. In the second cylinder 23, a groove 25 is provided at the middle position of each axial direction. Thus, in the second cylinder 23, a flange 26 extending radially outward from the groove 25 is provided on both sides of the groove 25 in the axial direction.

[0043] The groove 25 includes a semicircular arc-shaped curved groove 25a and a pair of linear grooves 25b connected to both ends of the curved groove 25a and parallel to each other. Thus, the groove 25 and the flange 26 have non-circular cross-sectional shapes.

[0044] like Figure 2 As shown, the urging mechanism 30 includes a coil spring (elastic body) 31 and two hooks 40 disposed at both ends of the coil spring 31. The hooks 40 are connected to both ends of the coil spring 31 by hooking hook portions 31a at both ends of the coil spring 31, respectively.

[0045] The hooking parts 31a each have a shape obtained by bending a wire material constituting the coil spring 31 into a hook shape. The coil spring 31 has a spring constant of an amount capable of applying a preload of an appropriate magnitude to the ball joints 7a and 7b.

[0046] like Figure 8 As shown, the hook 40 is a member for bending and deforming a metal round bar. In addition, the metal round bar has an outer diameter dimension that is the same as the groove width of the groove portion 25 of the bushings 20a and 20b.

[0047] The hook 40 includes a first connection portion 40a whose center in the longitudinal direction is bent along an arbitrary first plane F1. In addition, the hook 40 includes a pair of second connection portions 40b whose ends in the longitudinal direction are bent along a second plane F2 that is orthogonal to the first plane F1. In each second connection portion 40b, a pair of straight line portions 41b extending parallel to each other are provided at both ends of a curved portion 41a in the shape of a semicircle.

[0048] The distance between the pair of second connecting portions 40b and the distance W between the groove portions 25 of the two bushings 20a and 20b mounted on the socket 9a (see Figure 3 .)equal.

[0049] In addition, each second connection portion 40 b has a shape that matches the shape of the groove portion 25 around the axis D.

[0050] The pair of second connecting parts 40b are hooked on the grooves 25 of the two bushings 20a and 20b mounted on the socket 9a. Then, the curved part 41a and the two straight parts 41b of the second connecting part 40b are closely attached to the groove bottoms of the respective grooves 25. That is, the curved part 41a of the hook 40 is closely attached to the curved groove 25a, and the straight part 41b is closely attached to the straight groove 25b. Thus, the two bushings 20a and 20b and the hooks 40 are integrally connected in a manner that does not rotate relative to each other around the axis D of the mounting pin 29.

[0051] The hook portion 31a of the coil spring 31 is hooked on the first connection portion 40a of the hook 40, and the second connection portion 40b of the hook 40 is hooked on the bushings 20a and 20b. When the second connection portion 40b is hooked on the groove portion 25 of the bushings 20a and 20b, the first connection portion 40a of the hook 40 extends parallel to the axis D of the mounting pin 29. Therefore, the hook portions 31a at both ends of the coil spring 31 are hooked on the two hooks 40 so as to be rotatable around an axis parallel to the axis D.

[0052] like Fig. 9 As shown, the connecting member 50 is a long strip-shaped member formed by stamping a metal flat plate. One connecting member 50 is arranged on each side of the axis D direction between the sockets 9a and 9b. In addition, each connecting member 50 has mounting holes 51a and 51b penetrating in the plate thickness direction near both ends in the longitudinal direction.

[0053] The mounting hole 51 a has an opening shape capable of penetrating the first cylindrical portion 22 a including the claw 24 a of the bushing 20 a in the axial direction of the first cylindrical portion 22 a .

[0054] The claw 24a has a width dimension smaller than the diameter of the cylindrical portion of the first cylindrical portion 22a, and a length dimension protruding in the radial direction to the same position as the outer shape of the flange portion 26. The claw 24a is a flat plate with a predetermined thickness. The claw 24a extends from the outer surface of the cylindrical portion of the first cylindrical portion 22a in a direction different from the longitudinal direction of the linear groove portion 25b, for example, in a direction forming an angle of 120°.

[0055] The mounting hole 51a has a notch 52 in a circumferential portion of a circular opening shape having an inner diameter slightly larger than the outer diameter of the cylindrical portion of the first tube portion 22a. The notch 52 is sized and shaped to allow the claw 24a to pass through, for example, a similar shape slightly larger than the claw 24a.

[0056] The mounting hole 51b also has a long hole-like opening shape of the first cylindrical portion 22b including the claw 24b that can penetrate the bushing 20b in the axial direction of the first cylindrical portion 22b. The claw 24b has: a width dimension that is the same as the diameter of the cylindrical portion of the first cylindrical portion 22b; and a length dimension that protrudes in the radial direction with a size larger than the outer diameter of the flange portion 26. In addition, the claw 24b is a flat plate with a predetermined thickness. The claw 24b extends from the outer surface of the cylindrical portion of the first cylindrical portion 22b in a direction different from the longitudinal direction of the linear groove portion 25b, for example, in a direction forming an angle of 30°.

[0057] The mounting hole 51b has a width dimension slightly larger than the width dimension of the claw 24b and a length dimension slightly larger than the dimension of the first tube portion 22b in the length direction of the claw 24b. The mounting hole 51b extends along the long axis direction of the connecting member 50 and allows the cylindrical portion of the first tube portion 22b to penetrate movably along the long axis direction of the connecting member 50.

[0058] In the connection member 50, the first cylindrical portions 22a and 22b disposed on the same side of the sockets 9a and 9b in the direction of the axis D are inserted through the mounting holes 51a and 51b, respectively.

[0059] In this case, the phases of the claws 24 a and 24 b passing through the mounting holes 51 a and 51 b and the longitudinal direction of the cutout 52 about the axis D are different.

[0060] The operations of the parallel link robot 1 and the connection structure 10 thus configured will be described below. In the following description, one of the two connection members 50 will be described as an example, and the description of the other connection member 50 will be omitted.

[0061] The parallel link robot 1 of the present embodiment is assembled as follows.

[0062] When assembling, a base unit, a movable part 3, three pairs of connecting rods 5a, 5b, and three connecting structures 10, 10' are prepared. The base unit is a structure in which three arms 4 and ball studs 8a, 8b are assembled from the base part 2. Each connecting rod 5a, 5b has a socket 9a, 9b and a mounting pin 29 installed at one end, and a socket 9a', 9b' and a mounting pin 29 installed at the other end.

[0063] When assembling the parallel link robot 1 , first, the two hooks 40 are connected to the coil springs 31 of the connection structures 10 , 10 ′, respectively. Specifically, the hooking portions 31 a on both sides of the coil spring 31 are hooked to the first connection portions 40 a of the two hooks 40 , respectively.

[0064] Next, a pair of bushings 20a and 20b are mounted on the mounting pins 29 of the sockets 9a and 9b of the connecting rods 5a and 5b. The bushings 20a and 20b are brought close to each other from both sides of the sockets 9a and 9b, and the mounting pins 29 are fitted into the hollow holes 21. Thus, the pair of bushings 20a and 20b are mounted so as to be rotatable around the axis D of the same mounting pin 29.

[0065] Similarly, a pair of bushings 20a, 20b are mounted on the mounting pins 29 of the sockets 9a', 9b' of the connecting rods 5a, 5b. In addition, bushings 20a, 20b are mounted on both ends of the mounting pins 29 of the sockets 9a', 9b' so as to be rotatable around the axis D of the mounting pins 29.

[0066] Then, the pair of second connection parts 40b of the hook 40 on one side of the connection structure 10 are hooked on the grooves 25 of the bushings 20a and 20b mounted on the socket 9a. Also, the pair of second connection parts 40b of the hook 40 on the other side are hooked on the grooves 25 of the bushings 20a and 20b mounted on the socket 9b.

[0067] Similarly, the hook 40 on one side of the connection structure 10' is hooked on the groove 25 of the bushing 20a, 20b mounted on the socket 9a'. Also, the hook 40 on the other side is hooked on the groove 25 of the bushing 20a, 20b mounted on the socket 9b'.

[0068] Then, one of the pair of connecting rods 5a and 5b, for example, the socket 9a and 9a' of the connecting rod 5a is brought close to the ball studs 8a and 8a', respectively. Furthermore, the sockets 9a and 9a' are inserted into the ball studs 8a and 8a' from the outside in the direction of the axis A. After that, the connecting rod 5b on the other side is grasped, and the two coil springs 31 are pulled in the tensile direction to increase the distance between the connecting rods 5a and 5b. Furthermore, the sockets 9b and 9b' of the connecting rod 5b are inserted into the ball studs 8b and 8b' from the outside in the direction of the axis A, respectively. As a result, the ball studs 8a and 8b are clamped by the pair of sockets 9a and 9b in the direction of the axis A. Similarly, the ball studs 8a' and 8b' are clamped by the pair of sockets 9a' and 9b' in the direction of the axis A.

[0069] As a result, the pair of links 5 a and 5 b are connected by the two urging mechanisms 30 and are attached to the arm 4 and the movable portion 3 .

[0070] In this state, the two second connection parts 40b of one hook 40 are hooked on the grooves 25 of the two bushings 20a and 20b sandwiching the sockets 9a and 9b. Thus, the hook 40 integrally connects the pair of bushings 20a and 20b.

[0071] In addition, the flange portions 26 adjacent to both sides of each groove portion 25 are located at a position across the second connecting portion 40b of the hook 40 in the axial direction of the second cylindrical portion 23. Thus, the bushings 20a and 20b restrict the movement of the hook 40 in the axial direction of the mounting pin 29. In addition, the hook 40 restricts the bushings 20a and 20b from falling off the mounting pin 29. That is, the bushings 20a and 20b and the hook 40 can rotate integrally around the axis D of the mounting pin 29, and do not move relative to each other in other directions. The same is true for the two bushings 20a and 20b across the sockets 9a' and 9b'.

[0072] Then, the connecting member 50 is installed between the connecting rods 5a and 5b.

[0073] like Fig.10 As shown in the figure, the first tube portion 22a of the bushing 20a mounted on one connecting rod 5a is passed through the mounting hole 51a of the connecting member 50. By aligning the length direction of the cutout 52 of the mounting hole 51a with the phase of the claw 24a of the first tube portion 22a, it can be easily passed through. Moreover, after the claw 24a passes through the mounting hole 51a, the connecting member 50 is rotated around the axis D of the bushing 20a. Therefore, the phases of the mounting hole 51a and the claw 24a are offset, so that the connecting member 50 is mounted on the first tube portion 22a of the bushing 20a in a manner that does not fall off.

[0074] Then, the connecting member 50 is rotated around the axis D of the bushing 20a until the mounting hole 51b is aligned with the first cylindrical portion 22b of the bushing 20b. In this state, the phase of the claw 24b of the bushing 20b and the longitudinal direction of the mounting hole 51b of the connecting member 50 are not aligned.

[0075] So, if Fig.11 As shown, a force is applied to the connection portion between the hook portion 31a of the coil spring 31 and the first connection portion 40a of the hook 40. As a result, the coil spring 31 and the hook 40 rotate relative to each other, the coil spring 31 slightly expands, and the hook 40 and the bushing 20b rotate about the axis D.

[0076] When the bushing 20b rotates until the phase of the claw 24b coincides with the length direction of the mounting hole 51b, the first cylinder 22b is passed through the mounting hole 51b. When the claw 24b passes through the mounting hole 51b, the force applied to the coil spring 31 is released. Fig.12 As shown, the claws 24b and the mounting holes 51b are offset in phase, and the connecting member 50 is mounted on the first cylindrical portion 22b in a manner that does not fall off.

[0077] Similarly, the connection member 50 of the connection structure 10' is mounted between the bushings 20a, 20b of the mounting pin 29 mounted on the sockets 9a', 9b'. Fig.10 In the example shown, the claws 24b of the bushing 20b of the connection structure 10' extend in a direction different from the claws 24b of the connection structure 10. Thus, when the bushing 20b is inserted into the mounting hole 51b of the connection member 50 of the connection structure 10', the coil spring 31 does not interfere with peripheral components.

[0078] The remaining two pairs of links 5 a and 5 b can be assembled in the same manner, thereby completing the assembly of the parallel link robot 1 .

[0079] Thus, according to this embodiment, a force is applied in the direction of reducing the distance between the pair of links 5a and 5b, and the separation can be limited to a predetermined distance or more. In addition, there is an advantage that the connecting member 50 for limiting the expansion of the distance can be assembled or disassembled without using tools or jigs.

[0080] Furthermore, the bushings 20a and 20b supporting the connecting member 50 are held in a predetermined posture by the urging mechanism 30 with respect to the pair of connecting rods 5a and 5b. That is, the claws 24a and 24b and the mounting holes 51a and 51b of the connecting member 50 are located at a phase that prevents the connecting member 50 from falling off. Thus, when the connecting rods 5a and 5b are in motion, etc., the connecting member 50 can be prevented from accidentally falling off.

[0081] In addition, the mounting hole 51a of the connecting member 50 has a circular cross section, and the first cylindrical portion 22a passing therethrough does not move relative to the radial direction in the mounting hole 51a. Therefore, even if the parallel link robot 1 is operated, there is no rattling between the connecting member 50 and the bushing 20a.

[0082] In addition, since one mounting hole 51b of the connecting member 50 is a long hole, the first tube portion 22b is allowed to move slightly while passing through the mounting hole 51b. Therefore, there is also the advantage that even if the distance between the connecting rods 5a and 5b is shortened due to the aging of the ball joints 7a and 7b, it can be allowed to shorten.

[0083] In the present embodiment, the two hooks 40 are connected to the hooking portions 31a at both ends of the coil spring 31 so as to be rotatable about an axis parallel to the axis D. Alternatively, at least one of the hooks 40 may be integrally fixed to the hooking portion 31a.

[0084] For example, the hook 40 on the bushing 20a side may be fixed to the hook portion 31a by welding, etc. If the hook 40 on the bushing 20b side and the coil spring 31 are relatively rotatable, the phase of the claw 24b can be easily matched with the phase of the mounting hole 51b.

[0085] In addition, if Fig.13 As shown, the two hooks 40 can be welded to the hooking parts 31a on both sides of the coil spring 31. In this case, the assembly can be performed in a different order from the above-mentioned assembly method. For example, first, the connecting member 50 is connected to the bushings 20a and 20b. Then, while the coil spring 31 is stretched, the hooks 40 welded to both sides can be hooked to the bushings 20a and 20b.

[0086] That is, in a state where the urging mechanism 30 is not installed, the rotation of the bushings 20a and 20b around the axis D is not restricted. Therefore, the phases of the claws 24a and 24b are simultaneously aligned with the phases of the two mounting holes 51a and 51b of the connecting member 50, and the connecting member 50 is installed. Then, the bushings 20a and 20b are rotated around the axis D to shift the phases. Thereafter, the urging mechanism 30 is installed and the rotation of the bushings 20a and 20b is restricted.

[0087] This makes it possible to integrally handle the coil spring 31 and the two hooks 40. In addition, when the space for attaching the connection structure 10 is narrow, the assembly work can be facilitated.

[0088] In this case, the phases of the claws 24a and 24b with respect to the linear groove 25b can be freely set. Therefore, the claw 24b is also arranged at a phase that is greatly offset from the longitudinal direction of the mounting hole 51b, and the connection member 50 can be more reliably prevented from falling off.

[0089] In particular, if the phases of the claws 24a and 24b with respect to the linear groove portion 25b are made the same, the bushing 20b can be used as the bushing 20a. This can reduce the number of components and reduce manufacturing costs by making the components common. In addition, during the assembly work, it is not necessary to pay attention to the type of bushing, which can also improve the work efficiency.

[0090] In this case, by maintaining the shape of the mounting hole 51 b in the shape of an elongated hole, it is possible to cope with a change in the distance between the links 5 a and 5 b due to a change over time or the like.

[0091] In the present embodiment, the linear portion 41b of the hook 40 and the linear groove portion 25b of the bushings 20a and 20b are in contact with each other, thereby restricting the relative rotation of both. Alternatively, the bushings 20a and 20b may not have the linear groove portion 25b.

[0092] For example, Fig.14 As shown, the groove 25 of the bushing 20b is formed into a non-circular cross-sectional shape such as an ellipse. Furthermore, the bent portion 41a of the hook 40 is bent into a shape that matches the groove 25 of the bushings 20a and 20b.

[0093] Thus, when the urging mechanism 30 is connected, the elastic restoring force of the coil spring 31 restricts the rotation of the bushing 20b about the axis D. As a result, the phase shift between the claw 24b of the bushing 20b and the mounting hole 51b of the connecting member 50 about the axis D can be maintained as described above.

[0094] By configuring the bushing 20 a and the hook 40 connected to the bushing 20 a in the same manner, the same effect can be obtained.

[0095] The cross-sectional shape of the groove 25 of the bushings 20a and 20b may be non-circular other than an elliptical shape. Any cross-sectional shape may be adopted as long as the rotation around the axis D is restricted by making the bent portion 41a of the hook 40 in close contact.

[0096] For example, the cross-sectional shape of the groove 25 of the bushings 20a and 20b may be a circle eccentric to the axis D. Thus, the rotation of the bushings 20a and 20b about the axis D can be restricted by bringing the bent portion 41a of the hook 40 into close contact.

[0097] According to the present embodiment, one mounting pin 29 is pressed into the sockets 9a and 9b with both ends protruding in the direction of the axis D. Alternatively, two mounting pins 29 may be pressed into the sockets 9a and 9b from both outer sides in the direction of the axis D.

[0098] For example, the mounting pin 29 may be formed into a simple round rod shape and press-fitted from both outer sides in the axis D direction to a depth of about half of the pin hole 9h.

[0099] In this embodiment, the connection structure 10 is installed between the sockets 9a and 9b, and the connection structure 10' is installed between the sockets 9a' and 9b'. Alternatively, the connection structure 10' between the sockets 9a' and 9b' installed at the other ends of the connecting rods 5a and 5b may be omitted.

[0100] In this case, the coil spring 31 of the connection structure 10 only needs to have a spring constant sufficient to hold the four ball joints 7a, 7b, 7a', and 7b'.

[0101] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above-mentioned embodiments. In these embodiments, various additions, substitutions, changes, partial deletions, etc. can be made within the scope of the main idea of ​​the invention, or within the scope of the content recorded in the claims and the ideas and purposes of the present invention derived from their equivalents. For example, in the above-mentioned embodiments, the order of each action and the order of each process are shown as an example, and are not limited to this.

[0102] Description of reference numerals:

[0103] 1: Parallel linkage robot

[0104] 2: Basic Department

[0105] 3: Movable part

[0106] 4: Arm

[0107] 5a, 5b: Connecting rod

[0108] 10, 10′: Connection structure

[0109] 20a, 20b: Bushing

[0110] 24a, 24b: Claw (claw part)

[0111] 25: Groove

[0112] 30: Force applying mechanism

[0113] 31: Coil spring (elastic body)

[0114] 40: Hook

[0115] 50: Connecting parts

[0116] 51a, 51b: Mounting holes

[0117] C: Long axis

[0118] D: Axis

Claims

1. A connection structure, which connects two connecting rods, the two connecting rods have long axes and move in parallel with a gap, the connection structure is characterized in that: The connection structure has: A bushing mounted on each of the connecting rods in a manner capable of rotating about an axis perpendicular to a plane containing the two long axes; a force applying mechanism, which is mounted between the bushings of the two connecting rods and applies an elastic restoring force to the two bushings in a direction toward each other; and A connecting member having two mounting holes that can penetrate each of the bushings along the axial direction and limit the distance between the bushings to less than a predetermined distance, The bushing includes a claw portion protruding radially outward at a portion of the circumference of the end portion in the axial direction. Each of the mounting holes is formed into a shape that allows each of the bushes to be inserted only in a predetermined mounting phase around the axis that coincides with the claw portion of each of the bushes. The phase of each of the bushings about the axis is restricted to a phase that does not coincide with the installation phase by the elastic restoring force.

2. The connection structure according to claim 1, characterized in that: The bushing is arranged on both sides of the connecting rod along the axial direction. The urging mechanism is connected to the bushings on both sides of the connecting rod.

3. The connection structure according to claim 1, characterized in that: The urging mechanism includes an elastic body that generates the elastic restoring force, and hooks that are disposed at both ends of the elastic body and hooked on the bushing.

4. The connection structure according to claim 3, characterized in that: The hook and the bush have such shapes that, in a state where the hook is hooked, a relative rotation about the axis is maintained in a prohibited state.

5. The connection structure according to claim 4, characterized in that: At least one end of the elastic body is connected to the hook in a manner that allows them to rotate relative to each other around an axis parallel to the axis.

6. The connection structure according to claim 5, characterized in that: A groove portion that is recessed radially inward and on which the hook is hooked is provided at a midway position in the axial direction of the outer peripheral surface of the bush.

7. A parallel linkage robot, characterized in that: have: Basic Department; a movable portion disposed at a distance from the base portion; A plurality of arms connected to the base portion in a swingable manner; two pairs of connecting rods, which connect the arm and the movable part and have long axes parallel to each other; as well as The connecting structure according to claim 1 is arranged between a pair of connecting rods.

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