Hand and component supply system comprising the same

Abstract

To provide a hand that has a simple configuration and can stably pick up a cylindrical workpiece slightly inclined with respect to a conveyance base and cylindrical workpieces with different diameters, and a component supply system comprising the same.SOLUTION: A gripping part 38 of a hand 6 according to the present invention has a pair of claws 46 that move in an opening / closing direction to grip or release a workpiece W. The claws 46 are supported at a base end part by the gripping part 38 so as to be movable in the opening / closing direction, extend in a longitudinal direction from the gripping part 38, and have gripping surfaces 52 for gripping the workpiece W at tips thereof. The gripping surfaces 52 each have a first inclined surface 54 and a second inclined surface 56, where an angle α on the tip side is set to be smaller than an angle β on the base end side.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a parts supply system that includes a parts supply device that supplies workpieces such as mechanical parts and electronic parts to a transport table, and a robot that picks up the workpieces on the transport table and supplies them to the next process, and in particular, to a hand that has a gripping portion that grips or releases the workpiece. [Background technology]

[0002] There are devices that grip workpieces such as bolts and electronic components with claws attached to the tip of a hand (for example, Patent Documents 1 and 2). In the device of Patent Document 1, the workpiece gripping surface of the claws is flat. In the device of Patent Document 2, a notch is provided on the gripping surface of the claws to match the shape of the workpiece, and claws that match multiple workpiece shapes are rotatably arranged at the tip of the hand, and multiple types of workpieces can be lifted and transported by rotating the claws themselves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-283268 A [Patent Document 2] Patent No. 5408186 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a claw with a flat gripping surface as in Patent Document 1 grips a cylindrical workpiece such as a bolt or pin, the workpiece easily slips off the gripping surface and falls. As a result, the workpiece cannot be lifted, or it easily falls off during transportation. The claw in Patent Document 2 requires a rotation mechanism for rotating the claw in the hand, which increases the number of parts and complicates the configuration. In addition, if the workpiece is supplied at an angle, it becomes necessary to detect the workpiece's posture and control the rotation angle, which requires a sensor and a controller, making the configuration complicated.

[0005] An object of the present invention is to provide a hand that can stably pick up cylindrical workpieces that are slightly inclined with respect to a conveying table and cylindrical workpieces of different diameters with a simple configuration, and a part supply system equipped with the hand. [Means for solving the problem]

[0006] The hand of the present invention has a gripping section that grips or releases a workpiece, and an actuator that changes the attitude of the gripping section. The gripping section has a pair of claws that move in an opening / closing direction to grip or release the workpiece. The claws are supported at their base ends by the gripping section so as to be movable in the opening / closing direction, extend in the longitudinal direction from the gripping section, and have a gripping surface at their tip ends that grips the workpiece. The gripping surface has a first inclined surface that extends from an end on the base end side in the longitudinal direction toward the tip end side in the longitudinal direction at an incline in the opening direction in which the workpiece is released in the opening / closing direction, and a second inclined surface that extends from an end on the tip end side in the longitudinal direction toward the base end side in the longitudinal direction at an incline in the opening direction in which the workpiece is released in the opening / closing direction and is continuous with the first inclined surface. When viewed from a direction perpendicular to the longitudinal direction and the opening / closing direction, the tip side angle α formed by a tip side imaginary line extending the second inclined surface toward the tip side and the horizontal conveying surface of the conveying table is set to be smaller than the base side angle β formed by a base side imaginary line extending the first inclined surface toward the base end side and a parallel line parallel to the conveying surface (α<β).

[0007] According to this configuration, by reducing the tip side angle α, it becomes easier to pick up a workpiece that is slightly inclined with respect to the conveying table. Also, by increasing the base side angle β, the inclination angle γ between the first inclined surface and the second inclined surface becomes larger. As a result, the tangents between the four inclined surfaces of the claw and the cylindrical workpiece are close to the connecting portion of the first inclined surface and the second inclined surface. Therefore, even if the diameter of the cylindrical workpiece becomes large, it can be picked up so that the four surfaces become tangent planes. Therefore, cylindrical workpieces of different diameters can be stably picked up. In this way, not only cylindrical workpieces placed horizontally with respect to the conveying table, but also cylindrical workpieces slightly inclined with respect to the conveying table and cylindrical workpieces of different diameters can be stably picked up. Also, since a claw rotation mechanism, a sensor for detecting the posture of the workpiece, etc. are not required, the configuration is simple.

[0008] In this case, the tip side angle α may be set to 25° or more and 30° or less, and the base side angle β may be set to be greater than 50° and less than 60°. In other words, 25°≦α≦30° and 50°<β<60° may be satisfied. If the tip side angle α is smaller than 25°, the tip portion becomes thin and the rigidity decreases. Also, if the tip side angle α exceeds 30°, it is difficult to pick up a workpiece that is slightly inclined with respect to the conveyor table. The base side angle β is set so that the inclination angle γ matches the outer diameter of the cylindrical workpiece. It has been confirmed by a simulation that a cylindrical workpiece having a desired outer diameter can be stably picked up by setting the base side angle β to be greater than 50° and less than 60°.

[0009] In the present invention, the friction coefficient of at least one of the first inclined surface and the second inclined surface may be set to 0.2 or less, which makes it easier for the workpiece to move along the inclined surface, and allows a cylindrical workpiece that is slightly inclined with respect to the conveyor table to be gripped in a stable position where the four surfaces form tangent planes.

[0010] The part supply system of the present invention comprises a part supply device that supplies the workpiece to a transport table, a robot that transports the workpiece from a first area in which the transport table is located to a second area different from the first area, and a hand of the present invention that is attached to the end of the arm of the robot and picks up the workpiece on the transport table in the first area and places the workpiece in the second area.

[0011] With this configuration, the posture of the gripping part of the hand can be changed, so that when picking up a workpiece on the transport platform, the hand can be prevented from coming into contact with other workpieces or equipment. As a result, malfunctions of the hand or other equipment can be prevented, and work efficiency can be improved.

[0012] The part supply system of the present invention may further include a work detection means for detecting the position and posture of the work on the conveying table, and a control device for synchronously controlling the part supply device, the robot and the hand, and the control device may move the arm of the robot to the position detected by the work detection means, and cause the hand to grasp the work at an angle corresponding to the posture detected by the work detection means. Effect of the Invention

[0013] According to the hand and part supply system of the present invention, with a simple configuration, it is possible to stably pick up cylindrical workpieces that are slightly tilted with respect to the conveyor table, and cylindrical workpieces with different diameters. [Brief description of the drawings]

[0014] [Figure 1] 1 is a plan view showing a component supply system including a hand according to a first embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] 4 is a cross-sectional view showing a groove, which is one type of posture stabilization means of the component supply system. FIG. [Figure 5A] FIG. 2 is an enlarged front view showing a hand of the component supply system. [Figure 5B] 5B is a side view of the hand of FIG. 5A as viewed from the direction of arrow VB. [Figure 6A] FIG. 5B is a front view showing a hand in a different position from that in FIG. 5A. [Figure 6B] 6B is a side view of the hand of FIG. 6A as viewed in the direction of arrow VIB. [Figure 7A] FIG. 11 is a front view showing the state before the hand picks up a bolt-shaped workpiece. [Figure 7B] 7B is a side view of the hand of FIG. 7A as viewed in the direction of arrow VIIB. [Figure 7C] 7C is a rear view of the hand of FIG. 7B as viewed from the direction of arrow VIIC. [Figure 8A] FIG. 11 is a front view showing a state in which a bolt-shaped workpiece is picked up by the hand. [Figure 8B] 8B is a side view of the hand of FIG. 8A as viewed from the direction of arrow VIIIB. [Figure 8C] 8C is a rear view of the hand of FIG. 8B as viewed from the direction of arrow VIIIC. [Figure 9] FIG. [Figure 10A] FIG. 13 is a front view showing a modified example of the hand. [Figure 10B] FIG. [Figure 11A] FIG. 13 is a front view showing a hand according to a reference example. [Figure 11B] FIG. 11B is an enlarged view of part XIB in FIG. 11A. [Figure 12A] FIG. 11 is a front view showing the state before the hand picks up a bolt-shaped workpiece. [Figure 12B] 12B is a side view of the hand of FIG. 12A as viewed in the direction of arrow XIIB. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Figures 1 to 3 are a cross-sectional view, a side view, and a perspective view showing a part supply system SY according to a first embodiment of the present invention. In the following description, "upstream" and "downstream" refer to "upstream" and "downstream" in the work flow direction.

[0016] [System Wide] As shown in Fig. 1, the parts supply system SY uses a robot 4 and a hand 6 (Fig. 2) to pick up workpieces W that have been automatically aligned by a parts supply device 2 and supply them to an automatic machine or the like for the next process. In detail, the parts supply system SY includes the parts supply device 2 that supplies the workpieces W to a transport table 8, a robot 4 that transports the workpieces W from a first area A1 where the transport table 8 is located to a second area A2 different from the first area A1, and a hand 6 (Fig. 2) attached to the tip of an arm 10 of the robot 4.

[0017] In this embodiment, the workpiece W is a cylindrical member such as a bolt. However, the workpiece W is not limited to this and may be, for example, a machine part, an electronic part, a plastic part, a medicine, a medical product, food, miscellaneous goods, etc.

[0018] The part supply device 2, the robot 4 and the hand 6 are synchronously controlled by the control device 12. Specifically, the position and posture of the workpiece W on the transport table 8 is detected by the workpiece detection means 14, the arm 10 of the robot 4 moves to the position detected by the workpiece detection means 14, and the hand 6 grips the workpiece W at an angle according to the posture detected by the workpiece detection means 14. After that, the arm 10 of the robot 4 moves to the second area A2, and the hand 6 releases the workpiece W. This operation is then repeated.

[0019] In this embodiment, the workpiece detection means 14 is an imaging means such as a camera. However, the workpiece detection means 14 is not limited to a camera, and may be, for example, a distance sensor or a contact-type workpiece detection means. The camera may be provided exclusively for detecting the position and posture of the workpiece W, or may be used for another purpose. The camera may be fixed, or may be attached to the arm 4 of the robot 4.

[0020] [Parts supply device] The part supplying device 2 includes a vibrating bowl feeder 16 that aligns the stored workpieces W by vibration, and a transport table 8 that transports the workpieces W that are supplied in an aligned state from the vibrating bowl feeder 16. The transport table 8 is disposed along the outer periphery of the vibrating bowl feeder 16 so as to surround the outer periphery of the vibrating bowl feeder 16.

[0021] The vibrating bowl feeder 16 has a bowl-shaped bowl 18 having a conveying path 18a on its inner peripheral surface, and a vibrator (not shown) that vibrates the bowl 18. The works W contained in the bowl 18 are aligned by the vibration of the vibrator and sequentially conveyed along the conveying path 18a to a work discharge section 18b located at the top of the conveying path 18a.

[0022] The component supplying device 2 of this embodiment has a standing wall 20 around the entire circumference between the vibrating bowl feeder 16 and the conveying table 8, which protrudes above the upper surface of the conveying table 8. In other words, the standing wall 20 is located radially outside the vibrating bowl feeder 16 and radially inside the conveying table 8.

[0023] The work discharge portion 18b and a work recovery portion 32 (described later) are openings penetrating the standing wall 20. However, the configuration of the component supply device 2 is not limited to this, and a portion without the standing wall 20 may be formed in a part or the whole of the circumferential direction between the vibrating bowl feeder 16 and the conveyance table 8. In that case, the work discharge portion 18b and the work recovery portion 32 (described later) may be formed in an area without the standing wall 20 in the circumferential direction of the conveyance table 8.

[0024] The bowl-shaped bowl 18 has a bottom 18c for accommodating the workpiece W, and the conveying path 18a that spirals upward from the outer diameter side of the bottom 18c. The workpiece discharge portion 18b that penetrates the standing wall 20 is formed at the top of the conveying path 18a.

[0025] The workpieces W placed at the bottom 18a of the bowl 18 are fed out one after another while being aligned from bottom to top along the conveying path 18a on the inner surface of the bowl 18 due to the vibration of the bowl 18, and are discharged from the workpiece discharge section 18b at the top.

[0026] The conveying table 8 is arranged in a circular shape along the outer periphery of the vibrating bowl feeder 16. The conveying table 8 has a rotating disk 22 on whose upper surface a circular conveying surface 22a for the workpieces W is formed. The conveying surface 22a and the workpiece discharge section 18b are adjusted to approximately the same height position. This rotating disk 22 is driven to rotate by a rotary drive device (not shown). The rotary drive device is, for example, an electric motor, but is not limited to this. In addition, an encoder (not shown) is connected to the drive shaft of the drive motor, so that the phase position of the rotating disk 22 can be detected.

[0027] A work supply area 24, a sensing area 26, a pickup area 28, and a work collection area 30 are provided in a circumferential direction on the conveying surface 22a on the upper surface of the rotating disk 22. The work supply area 24 is an area to which the work W is supplied from the work discharge section 18b.

[0028] The sensing area 26 is located downstream in the work flow direction of the work supply area 24. In the sensing area 26, the position and posture of the work W are detected by the work detection means 14 described above.

[0029] The pickup area 28 is located downstream in the workpiece flow direction of the sensing area 26. In the pickup area 28, the robot 4 and the hand 6 pick up the workpiece W.

[0030] The workpiece recovery area 30 is located downstream of the pickup area 28 in the workpiece flow direction. In the workpiece recovery area 30, the workpieces W that were not picked up in the pickup area 28 are returned to the bowl 18. In detail, the workpieces W are returned from the conveying path 8 to the bowl 18 via the workpiece recovery section 32 arranged in the workpiece recovery area 30. As described above, in this embodiment, the workpiece recovery section 32 is an opening that penetrates the standing wall 20.

[0031] A posture stabilizing means 34 is provided on the transport surface 22a of the transport path 8. The posture stabilizing means 34 suppresses changes in the position and posture of the workpiece W being transported on the transport platform 8. In detail, the posture stabilizing means 34 suppresses changes in the posture of the workpiece W between the sensing area 26 and the pickup area 28. In this embodiment, the posture stabilizing means 34 is provided on the entire circumference of the transport surface 22a.

[0032] In this embodiment, the posture stabilizing means 34 is a groove 34 formed on the conveying surface 22a and extending in the circumferential direction of the conveying table 8. However, the posture stabilizing means 34 is not limited to a groove, and the posture stabilizing means 34 may be configured to have a different friction coefficient with the conveying surface 22a of the rotating disk 22, or may be made of a different material from the rotating disk 22. Specifically, the posture stabilizing means 34 may be configured such that fibrous felt or an elastic body such as rubber is attached to the conveying surface 22a of the metallic rotating disk 22.

[0033] 4, the presence of the grooves 34 makes it difficult for the workpiece W to roll even when the rotating disk 22 rotates, stabilizing the position and posture of the workpiece W. The grooves 34 can restrict the posture of a cylindrical workpiece W, such as a bolt, which is particularly unstable.

[0034] In this embodiment, the radially inner wall surface 34a of the groove 34 is inclined upward toward the radially inner side. On the other hand, the radially outer wall surface 34b of the groove 34 extends in a substantially vertical direction. That is, the angle θo of the radially outer wall surface 34b with respect to the bottom wall 34c of the groove 34 extending in the horizontal direction is approximately 90°, and the angle θi of the radially inner wall surface 34a with respect to the bottom wall 34c is greater than 90°. The angle θi of the radially inner wall surface 34a with respect to the bottom wall 34c is preferably 90° to 150°, and more preferably 135° to 150°. However, the angles θo and θi are not limited thereto.

[0035] Since the outer diameter side wall surface 34b extends vertically, it is possible to prevent the workpieces from moving radially outward due to the centrifugal force generated when the rotating disk 22 rotates. Also, since the inner diameter side wall surface 34a is inclined, the workpieces W that were not picked up can easily return to the bowl 18 on the radially inner side.

[0036] [robot] The robot 4 shown in Fig. 1 is a horizontal articulated robot having multiple arms 10, which move in a horizontal direction. The robot 4 rotates between a first area A1 where a transfer table 8 is located and a second area A2 for the next process. As shown in Fig. 3, the robot 4 of this embodiment has a base 36 fixed to the floor surface and three arms, first to third, 10A, 10B, and 10C.

[0037] The first arm 10A is a square bar-shaped member extending horizontally, and a base end 10Aa is connected to the upper surface of the base part 36 so as to be rotatable about a first vertical axis of rotation AX1. The second arm 10B is a square bar-shaped member extending horizontally, and a base end 10Ba is connected to a tip end 10Ab of the first arm 10A so as to be rotatable about a second vertical axis of rotation AX2.

[0038] The third arm 10C is a cylindrical shaft member extending vertically and inserted into the tip 10Bb of the second arm 10B. The third arm 10C is movable vertically relative to the tip 10Bb of the second arm 10B and rotatable about a third rotation axis AX3 in the vertical direction. The hand 6 is attached to the lower end 10Ca of the third arm 10C.

[0039] Each of the arms 10A, 10B, and 10C is driven by an actuator (not shown). The actuator is, for example, an electric motor, but is not limited to this. In this embodiment, the robot 4 is fixed to the floor surface, but it does not have to be fixed. In addition, the robot 4 is not limited to the structure of this embodiment, and any working robot can be applied.

[0040] [hand] The hand 6 picks up the workpiece W on the transport table 8 in the first area A1 (FIG. 1) and places the workpiece W in the second area A2 (FIG. 1). FIG. 5A is an enlarged front view of the hand 6, and FIG. 5B is a side view thereof. As shown in FIG. 5B, the hand 6 has a gripping portion 38 that grips or releases the workpiece W, and an actuator 40 with one or more degrees of freedom that changes the attitude of the gripping portion 38. In this embodiment, the actuator 40 uses a fluid such as compressed air.

[0041] The hand 6 is attached to the lower end 10Ca of the third arm 10C so as to be rotatable about the third axis of rotation AX3. The third arm 10C and the hand 6 of the robot 4 are connected by an L-shaped bracket 42. In detail, the lower end 10Ca of the third arm 10C is connected to the upper surface of the horizontal part 42a of the bracket 42, and the actuator 40 of the hand 6 is connected to the vertical part 42b of the bracket 42 by a bolt. In this embodiment, the hand 6 is attached to the inner surface of the vertical part 42b of the bracket 42, i.e., the surface on the third axis of rotation AX3 side. However, the shape of the bracket 42 and the arrangement of the hand 6 are not limited to this.

[0042] The actuator 40 has a fourth rotation axis AX4 extending horizontally. The gripper 38 is connected to the actuator 40 via a connecting member 44. The connecting member 44 is made of a plate-shaped long member, and a base end 44a of the connecting member 44 is connected to the actuator 40 so as to be rotatable around the fourth rotation axis AX4, and the gripper 38 is bolted to a tip end 44b of the connecting member 44. The actuator 40 rotates 90° in the direction of the arrow AR in FIG. 5B, so that the gripper 38 is positioned as shown in FIG. 6B. In this example, the fourth rotation axis AX4 intersects with the third rotation axis AX3, and the gripper 38 is disposed in the circumferential direction of the fourth rotation axis AX4 with respect to the actuator 40.

[0043] Figures 6A and 6B are respectively a front view and a side view when the actuator 40 is rotated 90° in the direction of the arrow AR (Figure 5B). Figures 5A and 5B show a state in which the hand 6 faces downward. Meanwhile, Figures 6A and 6B show a state in which the hand 6 faces sideways. In this manner, the gripping portion 38 can be changed to an arbitrary position by rotating the bracket 42 about the third rotation axis AX3, and the gripping portion 38 can be changed to an arbitrary posture by rotating the connecting member 44 about the fourth rotation axis AX4.

[0044] The gripping unit 38 of the first embodiment in FIG. 5A and FIG. 5B is a chuck device having a plurality of jaws 46 that can be opened and closed. In this embodiment, the gripping unit 38 has two jaws 46, but the jaws 46 may be three or more. The details of the jaws 46 will be described later. The gripping unit 38 may also be a suction pad. In this embodiment, the third rotation axis AX3 of the third arm 10C of the robot 4 and the fifth axis AX5 of the gripping unit 38 coincide with each other. Here, the fifth axis AX5 is the gripping center of the gripping unit 38. However, the third rotation axis AX3 and the fifth axis AX5 do not have to coincide with each other. In other words, the fifth axis AX5 may be offset in the horizontal direction with respect to the third rotation axis AX3.

[0045] [Operation] Next, a description will be given of the operation of the part supply system SY including the part supply device 2. The workpieces W placed in the bowl 18 shown in Fig. 1 are transported in an aligned state on the spirally provided transport path 18a by vibration to the workpiece discharge section 18b at the top of the bowl 18. The aligned works W are supplied from the workpiece discharge section 18b to the workpiece supply area 24.

[0046] The position and posture of the workpiece W supplied to the workpiece supply area 24 is detected by the workpiece detection means 14 in the downstream sensing area 26. Specifically, based on a signal from the workpiece detection means 14, the control device 12 determines whether the workpiece W can be picked up, and if so, what position and posture the hand 6 should be set to.

[0047] In a pickup area 28 downstream of the sensing area 26, the position of the hand 6 is set by moving the arm 10 of the robot 4 based on the determination result of the control device 12 based on a signal from the workpiece detection means 14, and the posture of the hand 6 is set by driving the actuator 40. The hand 6 picks up the workpiece W at this set position and posture.

[0048] At this time, if the position and posture of the workpiece W detected in the sensing area 26 differ from the position and posture of the workpiece W in the actual pickup area 28, there is a risk that the workpiece W may not be picked up by the hand 6. In this embodiment, the change in the position and posture of the workpiece W during transportation is suppressed by the posture stabilization means 34 consisting of a groove, so that the workpiece W can be picked up stably by the hand 6.

[0049] After the workpiece W is picked up, the arm 10 of the robot 4 is moved to move the hand 6 to the second area A2, the actuator 40 is driven to set the posture of the hand 6, and the hand 6 releases the workpiece W.

[0050] The workpieces W that could not be picked up in the pickup area 28 are returned into the bowl 18 from the downstream workpiece recovery area 30. At this time, since the radially inner wall surface 34a of the groove 34 is inclined upward toward the radially inner side, it is easy to return the workpieces W from the workpiece recovery area 30 to the bowl 18. The workpieces W returned into the bowl 18 are transported again by vibration on the transport path 18a. Thereafter, the same operation is repeated.

[0051] [Hand claw structure] The structure of claws 46 of hand 6 in this embodiment will be described with reference to Figures 7A to 10B. Figures 7A to 7C show a state before hand 6 picks up bolt-shaped workpiece W, and Figures 8A to 8C show a state after hand 6 picks up bolt-shaped workpiece W.

[0052] As shown in Fig. 7A, a pair of claws 46, 46 are provided at one end of the gripping portion 38 in the longitudinal direction D1. In this embodiment, the vertical direction corresponds to the longitudinal direction, and a pair of claws 46, 46 is provided at the lower end of the gripping portion 38. The gripping portion 38 is configured so that the pair of claws 46 can be opened and closed in parallel or around an arbitrary fulcrum. The claws 46 move in the opening and closing direction D2 (the left-right direction in Fig. 7A) to grip or release the workpiece W.

[0053] In the following description, the direction in which the gripping portion 38 and the claws 46 extend is referred to as the "longitudinal direction D1," and the direction in which the claws 46 open and close is referred to as the "opening / closing direction D2." In the opening / closing direction D2, the direction in which the workpiece W is gripped is referred to as the closing direction, and the direction in which the workpiece W is released is referred to as the opening direction. In addition, the direction perpendicular to both the longitudinal direction D1 and the opening / closing direction D2 (the left-right direction in FIG. 7B) is referred to as the "orthogonal direction D3."

[0054] The claws 46 are supported at their base ends 46a on the gripping portion 38 so as to be movable in the opening / closing direction D2. The claws 46 extend in the longitudinal direction from the gripping portion 38, downward in the illustrated example, and have gripping surfaces 52 at their tip ends 46b for gripping the workpiece W.

[0055] 9, the grip surface 52 has a first inclined surface 54 that extends from an end 52a on the base end side (upper side in FIG. 9) in the longitudinal direction D1 at an incline in the opening direction toward the tip end side (lower side in FIG. 9) in the longitudinal direction D1, and a second inclined surface 56 that extends from an end 52b on the tip end side (lower side in FIG. 9) in the longitudinal direction D1 at an incline in the opening direction toward the base end side (upper side in FIG. 9) in the longitudinal direction D1. The tip end side end of the first inclined surface 54 and the base end side end of the second inclined surface 56 are connected by a connecting portion 55.

[0056] That is, as shown in Fig. 9, when viewed from the orthogonal direction D3, the edge of the inclined surface 52 (the edge in the orthogonal direction) is V-shaped recessed in the opening direction. The four surfaces 54, 54, 56, 56 of the pair of claws 46, 46 form a tangential plane that comes into contact with the cylindrical workpiece W to be gripped. In addition, in the following description, the base end 52a may be referred to as the "base end corner 52a" and the tip end 52b may be referred to as the "tip end corner 52b."

[0057] When viewed from the orthogonal direction D3, the angle between the virtual line V1 on the tip side, which is an extension of the second inclined surface 56 to the tip side (lower side in FIG. 9), and the horizontal conveying surface 22a of the conveying table 8 is defined as the tip side angle α. Also, when viewed from the orthogonal direction D3, the angle between the virtual line V2 on the base side, which is an extension of the first inclined surface 54 to the base side (upper side in FIG. 9), and the parallel line LN parallel to the conveying surface 22a is defined as the base side angle β. Furthermore, the angle between the first inclined surface 54 and the second inclined surface 54 is defined as the inclination angle γ. In this embodiment, the tip side angle α is set to be smaller than the base side angle β. In other words, α<β.

[0058] Furthermore, in this embodiment, the tip side angle α is set to be equal to or greater than 25° and equal to or less than 30° (25°≦α≦30°), while the base side angle β is set to be greater than 50° and smaller than 60° (50°<β<60°).

[0059] The base end side end 52a and the tip end side end 52b of the claw 46, i.e., the base end side and tip end side corners 52a, 52b of the claw 46, are rounded. In other words, the base end side and the corners 52a, 52b of the claw 46 have an R shape. This makes it possible to prevent the corners 52a, 52b of the claw 46 from scratching the workpiece W. In this embodiment, both the base end side corner 52a and the tip end side corner 52b are provided with an R shape, but only the tip end side corner 52b may be provided with an R shape.

[0060] Furthermore, a surface 58 (lower surface 58 of claw 46 in FIG. 9) that forms corner portion 52b on the tip side and does not come into contact with the workpiece W is configured to be parallel to conveyance surface 22a when longitudinal direction D1 of gripping portion 38 is perpendicular to horizontal conveyance surface 22a of conveyance table 8. Alternatively, lower surface 58 of claw 46 may be inclined so that corner portion 52b on the tip side becomes the lower end with respect to conveyance surface 22a. This makes it possible to prevent interference between lower surface 58 of claw 46 and conveyance table 8.

[0061] 10A and 10B show modified examples of the claws 46 of this embodiment. In the example of FIG. 10A and FIG. 10B, a sliding member 60 is attached to the first inclined surface 54 and the second inclined surface 56 of the claws 46. The sliding member 60 is made of a material that has high slidability and is lower in hardness than the workpiece W. In this embodiment, the sliding member 60 has a surface friction coefficient set to 0.2 or less in order to obtain high slidability. The material of the sliding member 60 is, for example, polyoxymethylene (POM), monomer cast nylon (MC nylon), etc. However, the material of the sliding member 60 is not limited to this. By providing the sliding member 60, it is possible to prevent the workpiece W from being damaged. In addition, by setting the friction coefficient to 0.2 or less, the workpiece W becomes easier to move along the inclined surfaces 54, 56, and the cylindrical workpiece W that is slightly inclined with respect to the conveyor table 8 can be gripped in a stable position where the four surfaces 54, 56 are tangent planes.

[0062] In the example of FIG. 10A and FIG. 10B, the sliding member 60 is attached to both the first and second inclined surfaces 54, 56, but the sliding member 60 may be attached to only one of the first and second inclined surfaces 54, 56. In that case, the sliding member 60 may be attached only to the second inclined surface 56 on the tip side that is likely to damage the workpiece. The sliding member 60 may also be detachably attached to the inclined surfaces 54, 56. As an example, an engagement groove is provided on the inclined surfaces 54, 56, and the sliding member 60 is detachably attached to this engagement groove. However, the method of attaching the sliding member 60 is not limited to this. By making only the sliding member 60 replaceable, it is less expensive than replacing the entire claw 46, and maintenance costs can be reduced.

[0063] In this embodiment, the friction coefficient of the surface of the sliding member 60 is set to 0.2 or less in order to obtain high slidability, but, for example, the friction coefficient of the surface of the sliding member 60 may be set to be smaller than the friction coefficient of the surfaces of the claws 46 other than the inclined surfaces 54, 56. Also, instead of attaching the sliding member 60, the friction coefficient may be reduced by performing a surface treatment such as coating or polishing on the inclined surfaces 54, 56.

[0064] In the part supply system 2 of this embodiment, due to a change in the model number of a product produced on the manufacturing line, a workpiece W having a different shape from that input before the change may be input, or workpieces W of different shapes may be input simultaneously into the part supply device 2. Workpieces W of different shapes are often similar in shape, and for example, bolts, pins, etc. having the same screw diameter but different lengths are input by a changeover or input simultaneously.

[0065] The bolt is placed at a slight angle with respect to the horizontal conveying surface 22a because the outer diameter of the head is larger than the outer diameter of the shaft. However, in the case of an actuator 40 using compressed air or the like, the operating angle cannot be adjusted automatically, and manual adjustment takes time. If an electric actuator is used, the angle operation can be adjusted, but this increases costs and the control becomes complicated. Therefore, it is desirable to be able to pick up workpieces W that are inclined and horizontal with respect to the conveying surface 22a without changing the operating angle of the actuator 40.

[0066] In contrast, when picking up a cylindrical workpiece W from the radial direction, for example, as shown in the reference example of Figures 11A and 11B, a pair of claws 100 having inclined surfaces 102 with equal tip end angle α and base end angle β may be used to pick up the cylindrical workpiece W by contacting it with the four inclined surfaces 102.

[0067] 12A and 12B, if the angle at which the workpiece W is picked up is fixed in a direction perpendicular to the conveyor table 22a (the up and down direction in FIG. 12A), a slightly tilted workpiece W such as a bolt will have difficulty following the four inclined surfaces 102 of the claws, and the posture of the workpiece W after being picked up will be difficult to stabilize. Therefore, when the picked-up workpiece W is placed in the second area A2 (FIG. 1), the positional error of the workpiece W will be large.

[0068] In this way, a claw 100 having four inclined surfaces 102 with equal base end angle α and tip end angle β, such as the reference example shown in Figures 11A to 12B, cannot stably pick up all of the cylindrical workpieces W that are slightly inclined relative to the conveying table 8, cylindrical workpieces W that are placed horizontally, and cylindrical workpieces W of different diameters.

[0069] It is possible to make the workpiece W conform to the inclined surface 102 by increasing the gripping force of the gripping portion 38, but this would lead to an increase in the size and weight of the gripping portion 38, which would increase the interference area with the workpiece W and the component supply device 2, and reduce the workpiece carrying capacity of the robot 4 (FIG. 1). Furthermore, it is necessary to increase the rigidity of the jaws 100 in accordance with the gripping force of the gripping portion 38, which would make the jaws 100 expensive.

[0070] In contrast, in the hand 6A of this embodiment, as shown in Figures 7A, 7B, and 7C, when picking up a bolt-shaped workpiece W placed at an angle to the transport surface 22a from above in the radial direction, the workpiece W is picked up while being scooped up by the corners 52b on the tip side of the claws 46. At this time, since the tip side angle α is small, the workpiece W at an angle to the transport surface 22a can be easily picked up.

[0071] In addition, since the base end angle β is set to an appropriate value, as shown in Fig. 8C, the cylindrical workpiece W can easily follow the four inclined surfaces 54, 56. As a result, as shown in Fig. 8B, the workpiece W can be picked up in a horizontal and stable position.

[0072] [Effects] According to the above configuration, the posture stabilizing means 34 shown in Fig. 1 prevents the position and posture of the workpiece W from changing while it is being transported on the transport table 8. This stabilizes the pick-up operation of the workpiece W by the robot 4. As a result, the work efficiency is improved.

[0073] In particular, the position and posture of the workpiece W is detected in the sensing area 26, and the workpiece W with this detected position and posture is picked up in the pickup area 28. At this time, if the position and posture of the workpiece W in the pickup area 28 has changed from the position and posture of the workpiece W detected in the sensing area 26, the workpiece W will not be picked up, and work efficiency will decrease. In the above configuration, the posture stabilization means 34 suppresses changes in the position and posture of the workpiece W, so that the position and posture of the workpiece W do not change between the sensing area 26 and the pickup area 28. Therefore, the workpiece W is picked up stably, and work efficiency is improved.

[0074] Since the posture stabilizing means 34 is a groove formed in the conveying surface 22a, the posture stabilizing means 34 has a simple configuration and is easy to realize. In addition, since the radially inner wall surface 34a of the groove 34 is inclined upward toward the radially inner side, it becomes easy to return the workpieces W that were not picked up from the workpiece recovery area 30 to the bowl 18.

[0075] In addition, since the position and posture of the gripping portion 38 of the hand 6 can be changed, it is possible to prevent the hand 6 from contacting other workpieces W or equipment when picking up a workpiece W on the transport table 8. As a result, it is possible to prevent malfunctions in the hand 6 or other equipment, and work efficiency is improved.

[0076] In this manner, in the above embodiment, the gripping portion 38 of the hand 6 can approach the workpiece W at various angles, i.e., at an optimal position and posture. For example, the workpiece W may be picked up in the downward orientation of Figs. 5A and 5B, and then the posture may be changed to the horizontal orientation of Figs. 6A and 6B, and the workpiece W may be placed. The workpiece W may also be picked up in the horizontal orientation of Figs. 6A and 6B, and then the posture may be changed to the downward orientation of Figs. 5A and 5B, and the workpiece W may be placed. Alternatively, the orientations of the pick-up and placement may be the same, that is, both may face downward or both may face horizontally. In this manner, the posture can be freely changed, and therefore it is possible to avoid the hand 6 interfering with peripheral equipment, other workpieces, and the like.

[0077] A component supplying device 2 having a disk-shaped conveying table 8 can save space compared to one having a linear conveying table, but the hand is likely to come into contact with a part of the component supplying device 2. With this configuration, the position and posture of the gripping portion 38 of the hand 6 can be changed, so that the hand 6 can be prevented from coming into contact with a part of the component supplying device 2.

[0078] In the above embodiment, the component supplying device 2 has a standing wall 20 between the vibrating bowl feeder 16 and the transport table 8 that protrudes above the transport table 8, and there is a concern that the hand 6 may come into contact with this standing wall 20. According to the above configuration, the position and posture of the gripping portion 38 of the hand 6 can be changed, so that it is possible to prevent the hand 6 from coming into contact with the standing wall 20 of the component supplying device 2 when picking up a workpiece W on the transport table 8.

[0079] As shown in FIG. 9, by reducing the tip side angle α of the claw 46, it becomes easier to pick up the workpiece W that is slightly inclined with respect to the conveying table 8. Also, by increasing the base side angle β, the inclination angle γ between the first inclined surface 54 and the second inclined surface 56 becomes larger. As a result, the tangent line between the four inclined surfaces 54, 56 of the claw 46 and the cylindrical workpiece W becomes closer to the connecting portion 55 of the first inclined surface 54 and the second inclined surface 56. Therefore, even if the diameter of the cylindrical workpiece W becomes large, it can be picked up so that the four inclined surfaces 54, 56 become tangent planes. Therefore, even cylindrical workpieces W of different diameters can be stably picked up. In this way, not only cylindrical workpieces W placed horizontally with respect to the conveying table 8, but also cylindrical workpieces W that are slightly inclined with respect to the conveying table 8 and cylindrical workpieces W of different diameters can be stably picked up.

[0080] In this embodiment, the tip side angle α is set to 25° or more and 30° or less, and the base side angle β is set to be greater than 50° and smaller than 60°. In other words, the tip side angle α is set to 25°≦α≦30° and 50°<β<60°. If the tip side angle α is smaller than 25°, the corner portion 52b on the tip side becomes thin, and the rigidity of the tip portion of the claw 46 decreases. Also, if the tip side angle α exceeds 30°, it is difficult to scoop up the workpiece W that is slightly inclined with respect to the conveyance table 8. The base side angle β is set so that the inclination angle γ matches the outer diameter of the cylindrical workpiece W. It has been confirmed by simulation that by setting the base side angle β to be greater than 50° and smaller than 60°, a cylindrical workpiece W with a desired outer diameter can be stably picked up. In other words, by setting the base side angle β to 50°<β<60°, cylindrical workpieces W with various outer diameters can be stably picked up.

[0081] In this embodiment, the corner 52a on the base end side and the corner 52b on the tip end side of the claw 46 have an R shape. With this configuration, it is possible to prevent the corners 52a, 52b from damaging the workpiece W. Note that only the corner 52b on the tip end side, which is likely to come into contact with the workpiece W, may be provided with an R shape.

[0082] In this embodiment, the lower surface 58 of the claw 46 extends parallel to the transport surface 22a of the transport platform 8. This configuration makes it possible to prevent the claw 46 from interfering with the transport platform 8. Alternatively, the lower surface 58 of the claw 46 may be inclined so that the corner 52b on the tip side of the claw 46 is positioned at the lowest position during pick-up. This also makes it possible to prevent the claw 46 from interfering with the transport platform 8.

[0083] In this embodiment, as shown in Figures 10A and 10B, a sliding member 60 may be attached to the inclined surfaces 54, 56 of the claws 46. This configuration makes it possible to prevent the workpiece W from being damaged due to contact with the claws 46 during pick-up. In this case, the sliding member 60 may be detachably attached to the inclined surfaces 54, 56 of the claws 46. This makes it possible to replace only the sliding member 60 instead of the entire claws 46, making maintenance easier and reducing maintenance costs.

[0084] The present invention is not limited to the above-described embodiment, and various additions, modifications, and deletions are possible without departing from the scope of the present invention. Therefore, such modifications are also included in the scope of the present invention. [Explanation of symbols]

[0085] 2 Parts supply device 4. Robot 6 Hands 8 Transport platform 10 Arm 16 Vibratory Bowl Feeder 18 Bowl 18a Transport path 20 Standing Wall 22 Rotating Disc 22a Conveying surface 38 Gripping part 40 Actuator 44 Connecting member 46 Claws 48 Weakened Part 52 Gripping surface 54 First Inclined Surface 56 Second inclined surface α Tip side angle β proximal angle A1 First Area A2 Second Area D1 Longitudinal direction D2 Opening and closing direction D3 Orthogonal direction SY Parts Supply System Double work

Claims

1. A hand having a gripping part that grips or releases a workpiece and an actuator that changes the attitude of the gripping part, The gripping portion has a pair of claws that move in an opening / closing direction to grip or release the workpiece, The claws are supported at their base ends on the gripping portion so as to be movable in the opening and closing direction, extend in a longitudinal direction from the gripping portion, and have gripping surfaces at their tip ends for gripping the workpiece, The gripping surface is A first inclined surface extending from an end portion on the base end side in the longitudinal direction toward a tip end side in the longitudinal direction in an opening direction in which the work is separated in the opening / closing direction; A second inclined surface extends from the end portion on the tip side of the longitudinal direction toward the base end side of the longitudinal direction at an incline in the opening direction in which the work is separated in the opening / closing direction, and is continuous with the first inclined surface; having A hand in which, when viewed from a direction perpendicular to the longitudinal direction and the opening / closing direction, a tip-side angle α formed by a tip-side imaginary line extending the second inclined surface toward the tip side and a horizontal conveying surface of the conveying table is set to be smaller than a base-side angle β formed by a base-side imaginary line extending the first inclined surface toward the base side and a parallel line parallel to the conveying surface.

2. 2. The hand according to claim 1, wherein the tip side angle α is set to be equal to or greater than 25° and equal to or less than 30°, A hand in which the base end angle β is set to be greater than 50° and smaller than 60°.

3. 3. The hand according to claim 1, wherein a coefficient of friction of at least one of the first inclined surface and the second inclined surface is set to 0.2 or less.

4. A part supplying device that supplies the work to the conveyance table; a robot that transports the workpiece from a first area in which the transport table is arranged to a second area different from the first area; the hand according to claim 1 or 2, which is attached to a tip of an arm of the robot, and which picks up the workpiece on the conveyance table in the first area and places the workpiece in the second area; A parts supply system equipped with

5. The component supply system according to claim 4, further comprising: a workpiece detection means for detecting a position and a posture of the workpiece on the conveying platform; a control device that synchronously controls the part supply device, the robot, and the hand; Equipped with The control device of the component supply system moves the arm of the robot to the position detected by the work detection means and causes the hand to grasp the work at an angle corresponding to the posture detected by the work detection means.

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