Gripping device

Abstract

The gripping device (10) of the embodiment comprises a claw holding portion (22a, 22b), a cam (27), a pin (26a, 26b), a motor (31) and a guide rail holding portion (24). The claw holding portion (22a, 22b) is supported on the guide rail (23a, 23b) in a slidable manner. The cam (27) is provided with a spiral groove (27a, 27b) or a curved hole around its rotation center, and a hole (27c) is provided at the rotation center. One end of the pin (26a, 26b) is engaged with the claw holding portion (22a, 22b) side, and the other end is engaged with the groove (27a, 27b) or the curved hole of the cam (27). The motor (31) has a shaft (32) fixed to the hole (27c) of the cam (27). The guide rail holding portion (24) holds the guide rails (23a, 23b) and has a hole portion (24e), wherein the hole portion (24e) allows a positioning clamp (94) to be engaged with the end portion of the shaft (32) fixed to the cam (27), and allows the outer peripheral surface of the clamp (94) to contact the inner peripheral surface of the hole portion (24e).

Description

Technical Field

[0001] The invention relates to a gripping device. Background Art

[0002] In the past, automation of production lines has been promoted in order to reduce production costs, stabilize quality, etc., and automation achieved by robots has been introduced into many production lines due to their versatility. A gripping device for gripping a workpiece such as a component in the robot includes: a gripping portion having a plurality of claws; and a driving portion for driving the plurality of claws (for example, refer to Patent Document 1, etc.).

[0003] In a gripping device having a gripping portion that makes contact / separation by sliding two opposing claws, a cam having a spiral groove or a curved hole is sometimes used to make the claws slide. In such a structure, the pin engaged with the groove or the curved hole of the cam moves closer to or farther from the rotation axis by the rotation of the cam, thereby making the claws slide.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-144863 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, the above-mentioned cam is difficult to accurately position during assembly when the pin connected to the claw portion should properly contact the groove of the cam. If the positioning is not accurate, there will be problems such as reduced efficiency of sliding movement or wear of the cam.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gripping device that can appropriately bring a groove of a cam into contact with a pin by accurate positioning, thereby preventing a decrease in the efficiency of sliding movement and wear of the cam.

[0010] Solutions for solving problems

[0011] In order to solve the above-mentioned problems and achieve the purpose, a gripping device of one embodiment of the present invention comprises a claw holding portion, a cam, a motor and a guide rail holding portion. The claw holding portion is supported on the guide rail in a slidable manner. The cam is provided with a spiral groove or a curved hole around its rotation center, and a hole is provided at the rotation center. One end of the pin is engaged with the claw holding portion side, and the other end is engaged with the groove or the curved hole of the cam. The motor has a shaft fixed to the hole of the cam. The guide rail holding portion holds the guide rail and has a hole portion, and the hole portion can be engaged with a positioning fixture on the end of the shaft fixed to the cam, and the outer peripheral surface of the fixture can be in contact with the inner peripheral surface of the hole portion.

[0012] A gripping device according to one aspect of the present invention can provide a gripping device that can appropriately bring a cam groove and a pin into contact with each other through accurate positioning, thereby preventing a decrease in the efficiency of the sliding movement and abrasion of the cam. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is an explanatory diagram of a robot according to an embodiment.

[0014] Figure 2 It is a front view showing the structure of the gripping device according to the embodiment.

[0015] Figure 3 It is a side view showing the structure of the gripping device according to the embodiment.

[0016] Figure 4 It is a perspective view showing the structure of a fixing portion according to the embodiment.

[0017] Figure 5 FIG. (1) is a diagram for explaining a driving mechanism of a gripping device according to an embodiment.

[0018] Figure 6 It is an exploded view of the main parts of the grip.

[0019] Figure 7 FIG. (2) is a diagram for explaining a driving mechanism of a gripping device according to an embodiment.

[0020] Figure 8 It is a perspective view showing the structure of the cam according to the embodiment.

[0021] Fig. 9 This is a flowchart showing the cam manufacturing process.

[0022] Fig.10 is a flow chart showing the assembly process of the gripping device.

[0023] Fig.11 It is a perspective view showing the state of the gripping device in each assembly process.

[0024] Fig.12 This is a longitudinal sectional view when a cam is fixed to the shaft of the motor of the driving unit.

[0025] Fig.13 This is a longitudinal sectional view of the driving part and the fixing part when the gripping part is fixed.

[0026] Fig.14 This is a three-dimensional diagram of the guide rail retaining part (1).

[0027] Fig.15 This is a three-dimensional diagram of the guide rail retaining part (2). DETAILED DESCRIPTION

[0028] Hereinafter, the gripping device of the embodiment will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment. In addition, the dimensional relationship of each element in the drawings, the proportion of each element, etc. may sometimes be different from the actual ones. Sometimes the drawings may include parts with different dimensional relationships and proportions. In addition, the contents described in one embodiment or modification example are also applicable to other embodiments and modifications in principle.

[0029] <Overview of the robot>

[0030] First, refer to Figure 1 The outline of the robot 1 equipped with the gripping device 10 according to the embodiment will be described. Figure 1 1 is an explanatory diagram of a robot 1 according to an embodiment. The robot 1 is an example of a moving mechanism for moving the gripping device 10 to a desired position. It should be noted that the moving mechanism for moving the gripping device 10 to a desired position is not limited to a robot, and may be, for example, a linear actuator or the like.

[0031] The robot 1 is a so-called multi-joint robot having a plurality of joints (also referred to as robot modules) 3, and is installed in, for example, an assembly line or a manufacturing line of a product. Figure 1 In the figure, for convenience of explanation, a three-dimensional orthogonal coordinate system including the Z axis is shown with the vertical upward direction as the positive direction. This orthogonal coordinate system may also be shown in other figures.

[0032] The robot 1 includes a base 2, a plurality of joints 3, a plurality of arms 4, and a gripping device 10. Figure 1 2 shows an example in which the robot 1 includes six joints 3 and two arms 4 .

[0033] The six joints 3 are arranged in the order of the first joint 3A, the second joint 3B, the third joint 3C, the fourth joint 3D, the fifth joint 3E, and the sixth joint 3F between the base 2 on the upstream side of the power transmission in the robot 1 and the gripping device 10 on the downstream side. In addition, of the two arms 4, the first arm 4A is arranged on the upstream side of the power transmission in the robot 1, and the second arm 4B is arranged on the downstream side.

[0034] The base 2 supports the robot 1 as a whole by supporting the first joint 3A. The first joint 3A of the six joints 3 rotates relative to the base 2 around the axis AX1 as a virtual axis. The first joint 3A rotates (also called turns) on the X-Y plane. The second joint 3B is connected to the first joint 3A and rotates relative to the first joint 3A around the axis AX2.

[0035] In addition, the second joint 3B is connected to one end of the first arm 4A. The third joint 3C is connected to the other end of the first arm 4A. The fourth joint 3D is connected to the third joint 3C and rotates relative to the third joint 3C around the axis AX3 as a virtual axis. In addition, the fourth joint 3D is connected to one end of the second arm 4B and rotates relative to the second arm 4B around the axis AX4 as a virtual axis.

[0036] The fifth joint 3E is connected to the other end of the second arm 4B. The sixth joint 3F is connected to the fifth joint 3E and rotates relative to the fifth joint 3E around the axis AX5 as a virtual axis. The gripper 10 is connected to the sixth joint 3F. The gripper 10 rotates around the axis AX6.

[0037] The gripping device 10 is mounted on the sixth joint 3F at the distal end of the robot 1 to grip a workpiece such as a component. The structure of the gripping device 10 will be described later.

[0038] It should be noted that the rotation structure of the robot 1 composed of six joints 3 is not limited to the above. For example, the robot 1 may be configured to allow rotation between the second joint 3B and the first arm 4A, and between the fourth joint 3D and the second arm 4B.

[0039] Furthermore, each of the six joints 3 includes a rotation actuator (not shown). The robot 1 can perform multi-axis motions by the rotation actuator.

[0040] <Structure of the gripping device>

[0041] Next, refer to Figures 2 to 4 The structure of the gripping device 10 according to the embodiment will be described. Figure 2 1 is a front view showing the structure of the gripping device 10 according to the embodiment, Figure 3 It is a side view showing the structure of the gripping device 10 according to the embodiment. Figure 4 It is a perspective view showing the structure of the fixing portion 40 according to the embodiment.

[0042] like Figure 2 and Figure 3 As shown, the gripping device 10 includes a gripping portion 20, a driving portion 30, a fixing portion 40, and an encoder 50. The gripping portion 20 grips a workpiece such as a component. The gripping portion 20 includes a claw portion 21a, a claw portion 21b, a claw holding portion 22a, a claw holding portion 22b, a guide rail 23a, a guide rail 23b, and a guide rail holding portion 24.

[0043] The claws 21a and 21b are respectively configured to be movable in a predetermined direction, and to hold the workpiece by clamping it. Figure 2 and Figure 3 In the figure, the shapes of the claws 21a and 21b are shown as being tapered at the distal ends, but the shapes of the claws 21a and 21b are not limited to this shape and may be appropriately changed according to the type of workpiece to be gripped.

[0044] The claw holding portion 22a holds the claw portion 21a, and the claw holding portion 22b holds the claw portion 21b. The claw holding portion 22a and the claw holding portion 22b are respectively provided to be movable in a predetermined direction together with the claw portion 21a and the claw portion 21b. The guide rails 23a and the guide rails 23b extend in predetermined directions, respectively. For example, the guide rails 23a and the guide rails 23b are arranged and extended in a substantially parallel manner.

[0045] The guide rail holding portion 24 has a flat base portion 24a and a pair of wall portions 24b extending substantially perpendicularly from the base portion 24a. The guide rails 23a and 23b are held respectively by the pair of wall portions 24b. It should be noted that the detailed structure of the gripping portion 20 will be described later.

[0046] The driving unit 30 drives the claws 21a and 21b. The driving unit 30 includes a motor 31 and a shaft 32 (see Figure 5 The motor 31 generates a driving force for driving the claws 21 a and 21 b. The shaft 32 transmits the driving force generated by the motor 31 to the gripping portion 20.

[0047] It should be noted that, in the embodiment, the type of the motor 31 is not limited, for example, a hybrid stepping motor, a DC (direct current) motor, etc. In addition, the details of the driving mechanism of the claws 21a and 21b formed by the driving unit 30 will be described later.

[0048] The fixing unit 40 fixes the above-mentioned gripping unit 20 and driving unit 30 to the sixth joint unit 3F of the robot 1. Figure 4 As shown, the fixing portion 40 has a substantially U-shaped shape and includes a support portion 41, a connecting portion 42, and a beam portion 43. The fixing portion 40 can be manufactured by, for example, bending a sheet metal or cutting a metal block.

[0049] The support portion 41 is substantially flat and supports the gripping portion 20 and the driving portion 30 between the gripping portion 20 and the driving portion 30. For example, the support portion 41 has a surface side ( Figure 2 and Figure 3 The guide rail holding portion 24 of the gripping portion 20 is supported on the negative direction side of the Z axis. Figure 2 and Figure 3 The support portion 41 is provided with an opening 44 for receiving an annular protrusion 38 ( Figure 5 )Embed.

[0050] The connecting portion 42 is substantially in the shape of a flat plate and is connected to the sixth joint portion 3F of the robot 1. Figure 4 As shown, a threaded hole 42a is formed at a predetermined position in the connection portion 42, and the connection portion 42 can be connected to the sixth joint portion 3F by threading with a screw, a bolt, etc. The connection portion 42 is provided, for example, at a position substantially parallel to and facing the support portion 41.

[0051] It should be noted that a hole 42b is provided at the approximate center of the connecting portion 42. The hole 42b is a through hole for the pressing rod 92 of the clamp to be inserted when the cam 27 is fixed (pressed) to the shaft 32 of the drive portion 30 described later. The cam 27 is used to slide the claws 21a and 21b. It should be noted that a hole is also provided at a position corresponding to the hole 42b at the bottom of the drive portion 30 fixed to the connecting portion 42, and the axis of the clamp can pass through the connecting portion 42 of the fixing portion 40 and the bottom of the drive portion 30 (the bottom of the motor housing 33) from the outside to press the shaft 32 of the drive portion 30.

[0052] The beam portion 43 is substantially in the shape of a flat plate, and connects the support portion 41 and the connection portion 42. The beam portion 43 is substantially perpendicular to the support portion 41 and the connection portion 42, for example.

[0053] As described above, in the gripping device 10 of the embodiment, the gripping unit 20 is fixed to the robot 1 via the fixing unit 40 . That is, in the embodiment, the gripping unit 20 is fixed to the robot 1 without the driving unit 30 .

[0054] The encoder 50 detects the rotational position of the motor 31. The encoder 50 is disposed at a position closer to the motor 31 than the support portion 41 of the fixing portion 40. For example, the encoder 50 is disposed on the opposite side of the support portion 41 relative to the motor 31. It should be noted that in the embodiment, the type of encoder 50 is not limited, for example, an optical encoder, a magnetic encoder, etc. can be used. Based on the information of the encoder 50, the distance and speed of the claws 21a and 21b can be accurately controlled. It should be noted that the encoder 50 can also be omitted when there is no need to accurately control the distance and speed of the claws 21a and 21b.

[0055] <Drive mechanism of gripping device>

[0056] Next, refer to Figures 5 to 8 The details of the driving mechanism of the gripping device 10 will be described. Figure 5 and Figure 7 It is a diagram for explaining the driving mechanism of the gripping device 10 according to the embodiment. Figure 6 2 is an exploded view of the main parts of the grip portion 20 . Figure 8 2 is a perspective view showing the structure of the cam 27 according to the embodiment. Figure 5 and Figure 7 In the figure, the claw portion 21a, the claw portion 21b, the rail holding portion 24 and the fixing portion 40 are omitted for ease of understanding. Figure 6 In the figure, illustration is omitted except for the claw holding portion 22a, the claw holding portion 22b, the guide rail 23a, the guide rail 23b, the sliding moving portion 25a, the sliding moving portion 25b, the pin 26a, and the pin 26b.

[0057] like Figures 5 to 7 As shown, the sliding moving part 25a is configured to be able to slide and move guided by the guide rail 23a, and the sliding moving part 25b is configured to be able to slide and move guided by the guide rail 23b. That is, the sliding moving part 25a slides and moves along the extension direction of the guide rail 23a, and the sliding moving part 25b slides and moves along the extension direction of the guide rail 23b.

[0058] Furthermore, the claw holding portion 22a is fixed to the sliding moving portion 25a, and the claw holding portion 22b is fixed to the sliding moving portion 25b. Figure 5 As shown, the pin 26a is fixed to the claw holding part 22a, and the pin 26b is fixed to the claw holding part 22b. It should be noted that bearings are provided at the ends of the pins 26a and 26b. Therefore, the claw holding part 22a and the pin 26a slide and move together with the sliding moving part 25a, and the claw holding part 22b and the pin 26b slide and move together with the sliding moving part 25b.

[0059] The cam 27 transmits the driving force from the motor 31 to the pins 26a and 26b. Figure 8As shown, the cam 27 is roughly disk-shaped and is formed with a spiral groove 27a, a groove 27b and a circular hole 27c. The grooves 27a and 27b are formed to gradually move away from (or approach) the center of the cam 27 as it rotates. The circular hole 27c is formed at the rotation center of the cam 27 and is the fitting part of the motor 31 and the shaft 32. It should be noted that the grooves 27a and 27b are grooves with a spiral concave portion on one side and a bottom, which is conducive to maintaining the strength of the cam 27, but if the strength allows, a curved hole without a bottom and a through hole can also be used.

[0060] And, if Figure 5 As shown, the pin 26a is slidably inserted into the groove 27a of the cam 27, and the pin 26b is slidably inserted into the groove 27b. In addition, the shaft 32 extending from the motor 31 is inserted into the circular hole 27c, and the cam 27 is fixed on the shaft 32.

[0061] The shaft 32 is rotated by the driving force generated by the motor 31 . Therefore, the cam 27 is rotated by the driving force of the motor 31 via the shaft 32 .

[0062] Here, when the cam 27 is rotated in a predetermined rotation direction R1 by the motor 31 , a force is applied to the pins 26 a and 26 b guided by the spiral grooves 27 a and 27 b in a direction approaching the center of the cam 27 .

[0063] Here, the pin 26a is provided so as to be slidable along the guide rail 23a together with the slide-movable portion 25a. Thus, the pin 26a moves toward the center of the cam 27 and toward the extending direction of the guide rail 23a, that is, the predetermined direction D1.

[0064] Furthermore, since the pin 26a is fixed to the claw holding portion 22a, the claw holding portion 22a and the claw portion 21a (not shown) move in the direction D2 which is the same direction as the above-mentioned direction D1.

[0065] Similarly, the pin 26b is provided so as to be slidable along the guide rail 23b together with the slide-movable portion 25b. Thus, the pin 26b moves toward the center of the cam 27 and toward the extending direction of the guide rail 23b, that is, the predetermined direction D3.

[0066] Furthermore, since the pin 26b is fixed to the claw holding portion 22b, the claw holding portion 22b and the claw portion 21b (not shown) move in the direction D4 which is the same direction as the above-mentioned direction D3.

[0067] Furthermore, since the guide rails 23a and 23b are arranged substantially parallel to each other, the drive unit 30 can move the claws 21a and 21b in directions D2 and D4, which are directions in which they approach each other, by rotating the cam 27 in the rotation direction R1. In addition, the drive unit 30 can move the claws 21a and 21b in directions in which they move away from each other by rotating the cam 27 in the direction opposite to the rotation direction R1.

[0068] According to the mechanism described so far, in the embodiment, the motor 31 is rotated to appropriately control the distance between the claws 21 a and 21 b , so that the workpiece can be gripped by the claws 21 a and 21 b .

[0069] In addition, in the embodiment, the motor 31 is provided between the support portion 41 and the encoder 50. Thus, when stress is applied to the gripping portion 20 from the workpiece, the stress can be absorbed by the fixing portion 40 via the support portion 41, thereby suppressing the vibration of the encoder 50 due to the stress. As a result, the detection accuracy of the encoder 50 can be improved.

[0070] <Cam production>

[0071] Fig. 9 2 is a flow chart showing the manufacturing process of the cam 27. Fig. 9 In the process, the cam 27 before sintering is first manufactured by die molding using a sintered material for die molding (step S11). As the sintered material for die molding, for example, an iron-based sintered material is used. By using the iron-based sintered material, a cam 27 with high strength can be obtained. Since the outer shape is reduced by sintering in the next step, the die for molding the cam 27 before sintering is designed in a manner taking into account the reduction amount.

[0072] Next, the cam 27 before sintering is sintered (step S12). The cam 27 is solidified by sintering. The cam 27 before sintering is formed into a uniform size by die molding, and the shrinkage amount is accurately managed during sintering. Therefore, compared with the case of manufacturing one by one by machining such as cutting and wire cutting, it can be manufactured at a low cost and can be set as a cam with small dimensional deviation (ensure dimensional accuracy).

[0073] Next, the sintered cam 27 is carburized and quenched (step S13). Carburization and quenching is a method in which carbon is added to the surface of the cam 27 by gas carburization or the like, and then carbon is infiltrated into the surface by quenching and tempering. By carburization and quenching, a carburized layer can be formed on the surface of the cam 27 to increase the hardness of the surface. That is, the grooves 27a and 27b of the cam 27 are portions for the bearings provided on the pins 26a and 26b to slide, and by setting the hardness equal to or higher than that of the bearings, the wear resistance can be improved.

[0074] Next, the cam 27 is impregnated with resin (step S14). The resin impregnation is performed, for example, by the following method: immersing in a liquid such as an acrylic thermosetting resin as a sealing material for sintering, and curing it by heating after the resin has infiltrated. The cam 27 after sintering has many tiny pores (holes) formed on the surface, and the resin material filled in the pores on the surface is contained by the resin impregnation. When the cam 27 is embedded in the gripping device 10, grease is applied to lubricate the sliding of the pins 26a and 26b. Without resin impregnation, the base oil of the grease will be taken into the pores of the cam 27 due to the capillary phenomenon, so that the grease will deteriorate, which may hinder the movement. However, by pre-impregnating with resin, the intake of the base oil can be suppressed and the deterioration of the grease can be prevented.

[0075] It should be noted that the groove 27 a , the groove 27 b , and the circular hole 27 c of the cam 27 may be subjected to additional processing such as grinding to improve the smoothness.

[0076] <Assembly of the gripping device 10>

[0077] Fig.10 is a flow chart showing the assembly process of the gripping device 10, Fig.11 1 is a perspective view showing the state of the gripping device 10 in each assembly process. Fig.10 and Fig.11 In the process, the driving unit 30 including the motor 31 is first prepared (step S21). Then, the driving unit 30 is fixed to the fixing unit 40 (step S22). At this time, the positions of each other are defined by the opening 44 of the fixing unit 40 and the annular protrusion 38 of the motor 31. It should be noted that, regarding the fixing of the driving unit 30 and the fixing unit 40 of the fixing unit 40, there is a method of fixing a through hole provided in the fixing unit 40 with a threaded hole provided in the motor housing 33 of the motor 31 by screws, etc.

[0078] Next, the cam 27 is press-fitted into the shaft 32 of the motor 31 of the driving unit 30 (step S23 ). Fig.12 This is a longitudinal sectional view of the shaft 32 of the motor 31 of the driving unit 30 when the cam 27 is fixed, with the driving unit 30 and the like being relative to each other. Fig.11 An inverted state (a state in which the cam 27 is located on the lower side) is shown.

[0079] exist Fig.12 In the embodiment, the shaft 32 of the motor 31 is rotatably supported by bearings 34 and 35. A rotor 36 is fixed to the shaft 32, and a stator 37 is fixed to a position on the motor case 33 side facing the outer peripheral surface of the rotor 36 in the axial direction.

[0080] On the other hand, a circular recess 91a is provided on the flat mounting table 91 of the pressing fixture. Before the cam 27 is fixed to the shaft 32 of the motor 31, the center of the cam 27 is aligned with the recess 91a of the mounting table 91, and the cam 27 is mounted in a state where the surface of the cam 27 having the grooves 27a and 27b is in contact with the mounting table 91.

[0081] In this state, the driving part 30 and the fixing part 40 are moved to the upper part of the cam 27, and the shaft 32 of the motor 31 is aligned to the upper part of the circular hole 27c of the cam 27. Then, the pressing rod 92 of the pressing jig is inserted from the bottom side of the driving part 30 (the upper part in the figure) through the hole 42b of the fixing part 40 and the hole 33a of the motor housing 33, and the end of the pressing rod 92 of the pressing jig contacts the end of the shaft 32 on the side opposite to the side fixed to the cam 27. By applying force to the pressing rod 92 from the upper part in the figure, the shaft 32 is pressed into the circular hole 27c of the cam 27. The convex part 32a of the shaft 32 protruding from the cam 27 is accommodated in the concave part 91a of the mounting table 91.

[0082] The shaft 32 of the motor 31 and the cam 27 are fixed by pressing, so that a tight fixation is achieved by solid-solid contact, and there is almost no problem of idling due to the bonding strength being unable to withstand a large load as in the case of fixation achieved by bonding. The shaft 32 of the motor 31 and the cam 27 are reliably fixed, thereby improving the reliability of the gripping action.

[0083] In addition, in the case of fixing by bonding, it is necessary to wipe off the adhesive overflowing from the bonding portion, but fixing by pressing does not require such an operation, which can simplify the operation. Moreover, when the shaft 32 is pressed into the cam 27, the force applied to the shaft 32 from the pressing rod 92 is directly borne by the mounting table 91, so that no inappropriate load is applied to the motor 31, and the motor 31 is not damaged.

[0084] Back to Fig.10 and Fig.11 Unlike the driving unit 30 side, the guide rail 23a, the guide rail 23b, the sliding moving part 25a, the sliding moving part 25b, the pin 26a, the pin 26b ( Fig.11 The claw holding portion 22a and the claw holding portion 22b are installed on the guide rail holding portion 24 (step S24).

[0085] Next, the drive unit 30 and the fixing unit 40 having the cam 27 pressed into the shaft 32 (step S23) and the rail holding unit 24 having the rails 23a, 23b, etc. installed thereon (step S24), and the fixing unit 40 and the rail holding unit 24 are fixed (step S25). Regarding the fixing of the fixing unit 40 and the rail holding unit 24, for example, there is a method of fixing a through hole provided in the fixing unit 40 and a threaded hole provided in the rail holding unit 24 by screws.

[0086] Fig.13 The longitudinal cross-sectional view of the driving part 30 and the fixing part 40 when the gripping part 20 is fixed is shown in FIG. Fig.11 The inverted state (the state where the cam 27 is located at the lower side) is shown. Fig.13 In the embodiment, a support rod 94 is provided upright from a flat mounting table 93 of the assembly jig, and a recess 94a is provided at the distal end of the support rod 94.

[0087] In this state, the guide rail holding part 24 on which the guide rails 23a, 23b, etc. are mounted is placed with the support rod 94 on the mounting table 93 as the center so that the claw holding part 22a, 22b are located on the mounting table 93 side. At this time, the end of the support rod 94 is inserted in a state where its outer peripheral surface contacts the inner peripheral surface of the circular hole 24e provided in the guide rail holding part 24. At this time, the circular hole 24e contacts the support rod 94 with a small clearance to the extent that the support rod 94 can be removed. For example, the clearance at this time is 10 μm.

[0088] Fig.14 and Fig.15 is a perspective view of the guide rail holding portion 24, Fig.14 This is the state when viewed from the gripping portion 20 side (same as Figure 5 similar perspective), Fig.15 This is the state when viewed from the driving unit 30 side. Fig.15 The Y-Y section in is equivalent to Fig.13 The guide rail holding portion 24 is provided.

[0089] exist Fig.14 and Fig.15 In the embodiment, the guide rail holding portion 24 is formed with a surface for fixing the guide rails 23a and 23b ( Figure 5 The base 24a has two wall portions 24b (such as the base 24a). A circular recess 24c is provided on the back of the base 24a. A circular hole 24e is provided in the center between the two wall portions 24b of the base 24a, and two long holes 24d are provided across the circular hole 24e. As described above, the support rod 94 of the assembly jig is inserted into the circular hole 24e. The two long holes 24d provide space for the two pins 26a and 26b to slide.

[0090] Back to Fig.13The circular hole 24e of the guide rail holding part 24 is inserted into the support rod 94 of the assembly jig, whereby the center of the guide rail holding part 24 on which the guide rails 23a, 23b, etc. are mounted is positioned on the mounting table 93. That is, the ends (lower ends in the figure) of the claw holding parts 22a and 22b are positioned in the vertical direction by contacting with the mounting table 93, and are positioned in the plane of the mounting table 93 by the contact between the outer circumferential surface of the support rod 94 and the inner circumferential surface of the circular hole 24e of the guide rail holding part 24.

[0091] In this state, the drive unit 30 and the fixing unit 40 into which the cam 27 is pressed are formed on the shaft 32, and the cam 27 side is the support rod 94 side, and the convex portion 32a at the end of the shaft 32 is engaged with the concave portion 94a at the end of the support rod 94. The claw holding portions 22a and 22b connected to the pins 26a and 26b are fixed to the sliding moving portions 25a and 25b ( Figure 5 ), the sliding moving parts 25a, 25b and the guide rails 23a, 23b ( Figure 5 ) are engaged, and the guide rails 23a and 23b are fixed to the guide rail holding portion 24. On the other hand, since the cam 27 is fixed to the shaft 32 of the motor 31, the positional relationship (coaxiality) of the guide rail holding portion 24 and the shaft 32 is important for the positional relationship between the cam 27 and the pins 26a and 26b. Therefore, when assembling the guide rail holding portion 24 side and the driving portion 30 side, the guide rail holding portion 24 and the fixing portion 40 are fixed by positioning the guide rail holding portion 24 and the shaft 32 based on a common assembly fixture for alignment (mounting table 93, support rod 94), which can be simply and accurately positioned.

[0092] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Various changes are possible unless it deviates from the summary.

[0093] For example, although the embodiment in which two claws are slidably moved has been described, only one claw may be slidably moved and the workpiece may be gripped between the claw and the claw that does not slide.

[0094] [0071As described above, the gripping device of the embodiment comprises: a claw holding part supported on the guide rail in a sliding manner; a cam having a spiral groove or curved hole around its rotation center and a hole at its rotation center; a pin having one end engaged with the claw holding part side and the other end engaged with the groove or curved hole of the cam; a motor having a shaft fixed to the hole of the cam; and a guide rail holding part that holds the guide rail and has a hole that allows a positioning fixture to be engaged with the end of the shaft fixed to the cam, and allows the outer peripheral surface of the fixture to contact the inner peripheral surface of the hole. Thus, a gripping device can be provided that can properly contact the groove of the cam with the pin through accurate positioning, thereby preventing a decrease in the efficiency of sliding movement and wear of the cam.

[0095] Furthermore, the shaft has a convex portion that can engage with the concave portion of the clamp at the end of the shaft that is exposed from the hole of the cam. This allows the shaft to be reliably positioned.

[0096] Furthermore, the fixing portion that holds the motor is fixed to the rail holding portion. Thus, the motor can be fixed to the rail holding portion in a state where the motor is fixed to the fixing portion.

[0097] In addition, the present invention is not limited to the above-mentioned embodiments. A gripping device formed by appropriately combining the above-mentioned components is also included in the present invention. In addition, those skilled in the art can easily deduce further effects and variations. Therefore, the broader scheme of the present invention is not limited to the above-mentioned embodiments, and various changes can be made.

[0098] Description of Reference Numerals

[0099] 10: gripping device; 20: gripping part; 22a, 22b: claw holding part; 23a, 23b: guide rail; 24: guide rail holding part; 27: cam; 27a, 27b: groove; 30: driving part; 31: motor; 32: shaft; 32a: convex part; 33: motor housing; 40: fixing part; 93: mounting table; 94: support rod; 94a: recessed part.

Claims

1. A gripping device, characterized in that: have: A claw holding portion is supported on the guide rail in a slidable manner; A cam having a spiral groove or curved hole around its rotation center and a hole at said rotation center; a pin, one end of which is engaged with the claw holding portion side and the other end of which is engaged with the groove or curved hole of the cam; a motor having a shaft fixed to the hole of the cam; and The guide rail holding portion holds the guide rail and has a hole portion, wherein a positioning fixture can be engaged with the end portion of the shaft fixed to the cam, and an outer peripheral surface of the fixture can contact an inner peripheral surface of the hole portion.

2. The gripping device according to claim 1, characterized in that: The shaft is provided with a convex portion that can be engaged with the concave portion of the clamp at the distal end thereof exposed from the hole of the cam.

3. The gripping device according to claim 1 or 2, characterized in that: A fixing portion for holding the motor is fixed to the guide rail holding portion.

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