Hand

Abstract

To provide a hand capable of stably picking up even workpieces of various shapes or attitudes.SOLUTION: A hand 6 comprises: a plurality of claws 46 that grip or release a workpiece W; a grip 38 that moves the claws 46 in a gripping direction DR1 for gripping the workpiece W and a releasing direction DR2 for releasing the workpiece W; and a rotation transmission mechanism 70 for rotating the workpiece W gripped by the claws 46 about a rotation axis X1 parallel to the gripping direction DR1 and the releasing direction DR2. The gripping surface 52 of each claw 46 includes a first slope 54 that inclines to extend in the releasing direction DR2 from the end of the base end side in an extending direction D2 to the tip side in the extending direction D2, and a second slope 56 that inclines to extend in the releasing direction DR2 from the end of the tip side in the extending direction D2 to the base end side in the extending direction D2.SELECTED DRAWING: Figure 7A

Description

[Technical Field]

[0001] The present invention relates to a hand having a gripping portion that grips or releases a workpiece such as a mechanical part or an electronic part. [Background technology]

[0002] There is a device that grips a workpiece such as a bolt or an electronic component with a claw attached to the tip of a hand (for example, Patent Document 1). In the device of Patent Document 1, the workpiece gripping surface of the claw is flat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-283268 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when gripping cylindrical workpieces such as bolts and pins with a flat gripping surface like the one in Patent Document 1, the workpiece is likely to slip off the gripping surface and fall, making it difficult to lift the workpiece or causing it to fall during transportation.

[0005] An object of the present invention is to provide a hand that can stably pick up workpieces of various shapes and postures. [Means for solving the problem]

[0006] The hand of the present invention includes a plurality of claws for gripping or releasing a workpiece, a gripping unit for moving the claws in a gripping direction to grip the workpiece and a release direction to release the workpiece, and a rotation transmission mechanism for rotating the workpiece gripped by the claws around a rotation axis parallel to the gripping direction and the release direction. The claws are supported at their base ends on the gripping unit so as to be movable in the gripping direction and the release direction, and have gripping surfaces at their tip ends for gripping the workpiece, extending in an extension direction from the base end to the tip end. The gripping surfaces have a first inclined surface extending from an end on the base end side in the extension direction toward the tip end side in the extension direction at an incline in the release direction, and a second inclined surface extending from an end on the tip end side in the extension direction toward the base end side in the extension direction at an incline in the release direction.

[0007] With this configuration, the gripping surface has a first inclined surface and a second inclined surface, allowing for picking up workpieces so that multiple surfaces are tangent to each other. This allows for stable picking up of workpieces that are tilted relative to the conveyor table or workpieces with unusual shapes, such as cylindrical workpieces with different diameters. Furthermore, the device is equipped with a rotation transmission mechanism that rotates the workpiece gripped by the jaws around a rotation axis parallel to the gripping and release directions, allowing for stable movement and placement of the workpiece regardless of the workpiece's orientation at the time of pickup.

[0008] In the present invention, when viewed from a direction perpendicular to the extension 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 the horizontal conveying surface of the conveying table may be 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. According to this configuration, by reducing the tip-side angle α, it becomes easier to scoop up workpieces that are slightly tilted with respect to the conveying table. Furthermore, by increasing the base-side angle β, the inclination angle γ formed by the first inclined surface and the second inclined surface becomes larger.

[0009] In this case, the tip angle α may be set to 25° or more and 30° or less, and the base 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 angle α is less than 25°, the tip portion becomes thin and rigidity decreases. Furthermore, if the tip angle α exceeds 30°, it becomes difficult to pick up a workpiece that is slightly tilted relative to the conveyor table. The base angle β is set so that the inclination angle γ matches the outer diameter of the cylindrical workpiece. Simulations have confirmed that setting the base angle β to be greater than 50° and less than 60° enables stable pickup of cylindrical workpieces with the desired outer diameter.

[0010] In the present invention, when viewed from a direction perpendicular to the extension direction and the opening / closing direction, the tip-side angle α formed by a virtual line extending the second inclined surface toward the tip side and the horizontal conveying surface of the conveying table may be set to be larger than the base-side angle β formed by a virtual line extending the first inclined surface toward the base side and a parallel line parallel to the conveying surface.

[0011] In the present invention, the coefficient of friction 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 enables a cylindrical workpiece that is slightly inclined relative to the conveyor table to be gripped in a stable position where multiple surfaces form tangent planes.

[0012] In the present invention, the rotation transmission mechanism may include a rotating unit provided at the tip of the claw and rotatable relative to the claw about a rotation axis parallel to the opening / closing direction, and a second drive source that drives the rotating unit to rotate about the rotation axis, and the gripping surface may be formed on the rotating unit. With this configuration, the workpiece can be rotated about the rotation axis parallel to the opening / closing direction by the rotating unit, so that the orientation of the workpiece can be changed while it is being gripped. This reduces the operation time.

[0013] In this case, the rotation transmission mechanism and the claw portion may be integrated to form a sub-assembly, and the sub-assembly may be attached to the gripping portion. With this configuration, the claw portion having the rotation transmission mechanism can be applied to an existing gripping portion. In particular, it is easy to adapt to the size of the gripping mechanism and the length of the claw portion, making it highly versatile.

[0014] When the rotating unit and the second driving source are provided, the rotation transmission mechanism may further include a power transmission mechanism connected to at least one of the rotating units and moving together with the rotating unit in the gripping direction and the release direction to transmit the power of the second driving source to the rotating unit, and an extendable and retractable rotation mechanism that is extendable and retractable in the gripping direction and the release direction and transmits the rotation of the second driving source to the power transmission mechanism.

[0015] According to this configuration, a rotating part of the rotation transmission mechanism is separately provided at the tip of the jaw attached to the gripper, and the rotating part rotates the workpiece around a rotation axis parallel to the gripping and releasing directions of the jaw. The rotating part rotates using power from a second drive source that is provided independently of the power that opens and closes the jaw. As a result, even if the height of the workpiece to be gripped changes during a setup change, it is sufficient to replace the jaw and the rotation transmission mechanism supported by it, and there is no need to change the gripper. As a result, the length from the base of the jaw to the rotation axis can be easily changed.

[0016] In addition, the second drive source does not move in the gripping and releasing directions together with the jaws. This reduces the load in the gripping and releasing directions, allowing the jaws to operate at high speed. Furthermore, since only the rotating part is rotated, rather than the entire gripping part, the only rotating objects are the workpiece and the rotating part, reducing the weight and moment of inertia of the rotating object. As a result, high-speed rotation of the rotating part and low torque of the second drive source are possible, allowing for the second drive source to be made smaller and lighter.

[0017] When the power transmission mechanism and the telescopic rotation mechanism are provided, the telescopic rotation mechanism may have a first rotating shaft connected to the output shaft of the second drive source, a second rotating shaft connected to an inlet rotating body of the power transmission mechanism, and an telescopic rotation structure that transmits rotation of the first rotating shaft to the second rotating shaft and supports the second rotating shaft so that it can move relative to the first rotating shaft in the gripping direction and the release direction.

[0018] In this case, the telescopic rotating structure may include a cylindrical outer member provided at one end of the first rotating shaft and the second rotating shaft, an inner member provided at the other end of the first rotating shaft and the second rotating shaft and inserted into a hollow hole in the outer member, and rolling elements interposed between the outer member and the inner member to transmit rotation of the outer member to the inner member and support the member provided on the second rotating shaft so that it can move in the gripping direction and the releasing direction relative to the member provided on the first rotating shaft. With this configuration, rotational torque can be reliably transmitted in the rotational direction, and smooth movement with little resistance in the telescopic direction is possible.

[0019] Alternatively, the telescopic rotation structure may have a first gear provided on one of the first rotation shaft and the second rotation shaft, the first gear having an axial dimension longer than the opening / closing width of the gripping mechanism, and a second gear provided on the other of the first rotation shaft and the second rotation shaft, meshing with the first gear to transmit the rotation of the first gear and movable in the gripping direction and the release direction relative to the first gear. With this configuration, with a small number of parts, rotational torque can be reliably transmitted in the rotation direction and movement in the telescopic direction is possible. [Effects of the Invention]

[0020] The hand of the present invention can stably pick up workpieces that are tilted relative to the conveyor table, or workpieces with special shapes such as cylindrical workpieces with different diameters. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a plan view showing a component supply system equipped with a hand according to a first embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] 10 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 of a hand of the component supply system. [Figure 5B] 5B is a side view of the hand of FIG. 5A as seen from the direction of arrow VB. [Figure 6A] FIG. 5B is a front view showing a hand in a different position from that shown 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. 1 is a front view showing a hand according to a first embodiment of the present invention. [Figure 7B] 7B is a side view of the hand of FIG. 7A as viewed from the direction of arrow VIIB. [Figure 8] FIG. [Figure 9A] FIG. 2 is a perspective view showing the extension and retraction rotation mechanism of the hand. [Figure 9B] FIG. [Figure 9C] FIG. 9C is a cross-sectional view taken along line IXC-IXC in FIG. 9B. [Figure 10] FIG. [Figure 11A] FIG. 10 is a front view showing a modified example of the hand. [Figure 11B] FIG. [Figure 12A] FIG. 10 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. [Figure 12C]FIG. 12C is a rear view of the hand of FIG. 12B as seen from the direction of arrow XIIC. [Figure 13A] FIG. 10 is a front view showing a state in which a bolt-shaped workpiece is picked up by the hand. [Figure 13B] 13B is a side view of the hand of FIG. 13A as viewed from the direction of arrow XIIIB. [Figure 13C] 13C is a rear view of the hand of FIG. 13B as seen from the direction of arrow XIIIC. [Figure 14] FIG. 10 is a front view showing a modified example of the telescopic rotation mechanism of the hand. [Figure 15] FIG. 10 is a front view showing a modified example of the hand. [Figure 16A] FIG. 10 is a front view showing another modified example of the hand. [Figure 16B] FIG. 16B is a side view of the hand of FIG. 16A as viewed in the direction of arrow XVIB. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will now 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 component supply system SY equipped with a hand according to a first embodiment of the present invention. In the following description, "upstream" and "downstream" refer to "upstream" and "downstream" in the direction of work flow.

[0023] [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 that is different from the first area A1, and a hand 6 (Fig. 2) attached to the tip of an arm 10 of the robot 4.

[0024] 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 mechanical part, an electronic part, a plastic part, a drug, a medical product, a food product, a miscellaneous item, or the like.

[0025] The component supply device 2, robot 4, and hand 6 are synchronously controlled by a control device 12. Specifically, the position and posture of the workpiece W on the transport table 8 is detected by a 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 grasps the workpiece W at an angle corresponding to the posture detected by the workpiece detection means 14. Thereafter, 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.

[0026] 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 orientation of the workpiece W, or may be used for other purposes. The camera may also be fixed, or may be attached to the arm 4 of the robot 4.

[0027] [Parts supply device] The component supply 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.

[0028] The vibrating bowl feeder 16 has a bowl-shaped bowl 18 having a conveying path 18a on its inner circumferential 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.

[0029] The component supply device 2 of this embodiment has a standing wall 20 that protrudes above the upper surface of the conveying table 8 around the entire periphery between the vibrating bowl feeder 16 and 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.

[0030] The workpiece discharge portion 18b and a workpiece recovery portion 32 (described later) are openings that penetrate 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 part or all of the circumferential direction between the vibrating bowl feeder 16 and the conveyance table 8. In this case, the workpiece discharge portion 18b and the workpiece 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.

[0031] The bowl-shaped bowl 18 has a bottom 18c for accommodating the workpieces 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.

[0032] The workpieces W placed at the bottom 18a of the bowl 18 are fed out one after another in an aligned manner from bottom to top along the conveying path 18a on the inner surface due to the vibration of the bowl 18, and are discharged from the workpiece discharge section 18b at the top.

[0033] 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 the upper surface of which a circular conveying surface 22a for the work W is formed. The conveying surface 22a and the work discharge section 18b are adjusted to be at approximately the same height. This rotating disk 22 is driven to rotate by a rotation drive device (not shown). The rotation 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.

[0034] A work supply area 24, a sensing area 26, a pickup area 28, and a work collection area 30 are arranged in the 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.

[0035] The sensing area 26 is located downstream in the workpiece flow direction of the workpiece supply area 24. In the sensing area 26, the position and posture of the workpiece W are detected by the workpiece detection means 14 described above.

[0036] 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.

[0037] The workpiece collection area 30 is located downstream in the workpiece flow direction of the pickup area 28. In the workpiece collection 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 collection section 32 arranged in the workpiece collection area 30. As described above, in this embodiment, the workpiece collection section 32 is an opening that penetrates the standing wall 20.

[0038] A posture stabilizing means 34 is provided on the conveying surface 22a of the conveying path 8. The posture stabilizing means 34 prevents the position and posture of the workpiece W from changing while it is being conveyed on the conveying table 8. In detail, the posture stabilizing means 34 prevents the posture of the workpiece W from changing between the sensing area 26 and the pickup area 28. In this embodiment, the posture stabilizing means 34 is provided around the entire circumference of the conveying surface 22a.

[0039] 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, for example, to have a different coefficient of friction 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, for example, a fibrous felt or an elastic body such as rubber attached to the conveying surface 22a of the metallic rotating disk 22.

[0040] 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 particularly restrict cylindrical workpieces W, such as bolts, which are less stable, to a fixed posture.

[0041] 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 horizontally extending bottom wall 34c of the groove 34 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 to these values.

[0042] Because the outer diameter side wall surface 34b extends vertically, it is possible to prevent the workpieces from moving radially outward due to centrifugal force when the rotating disk 22 rotates. In addition, because 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.

[0043] [robot] The robot 4 shown in Fig. 1 is a horizontal articulated robot having multiple arms 10 that move horizontally. The robot 4 rotates between a first area A1 where a transport 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.

[0044] The first arm 10A is a square rod-shaped member extending horizontally, with a base end 10Aa connected to the upper surface of the base unit 36 ​​so as to be rotatable about a first vertical axis of rotation AX1. The second arm 10B is a square rod-shaped member extending horizontally, with a base end 10Ba connected to a tip end 10Ab of the first arm 10A so as to be rotatable about a second vertical axis of rotation AX2.

[0045] 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 is rotatable about a third vertical axis of rotation AX3. The hand 6 is attached to the lower end 10Ca of the third arm 10C.

[0046] 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. Furthermore, the robot 4 is not limited to the structure of this embodiment, and any working robot can be applied.

[0047] [hand] The hand (gripping device) of the present invention is characterized by having a rotation transmission mechanism that rotates the workpiece W, and having two inclined surfaces on the gripping surface that grips the workpiece W. However, Figures 5A to 6B show a hand 6 that does not have these rotation transmission mechanisms and inclined surfaces, and the rotation transmission mechanisms and inclined surfaces will be described in detail with reference to Figures 7A to 13C.

[0048] 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 unit 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 unit 38. In this embodiment, the actuator 40 uses a fluid such as compressed air.

[0049] 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. More specifically, the lower end 10Ca of the third arm 10C is connected to the upper surface of a horizontal portion 42a of the bracket 42, and the actuator 40 of the hand 6 is connected to a vertical portion 42b of the bracket 42 by a bolt. In this embodiment, the hand 6 is attached to the inner surface of the vertical portion 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.

[0050] 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 long, plate-shaped member, and a base end 44a thereof is connected to the actuator 40 so as to be rotatable about the fourth rotation axis AX4, and a tip end 44b thereof is connected to the gripper 38 by a bolt. When the actuator 40 is rotated 90° in the direction of arrow AR in FIG. 5B, 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 circumferentially of the fourth rotation axis AX4 relative to the actuator 40.

[0051] 6A and 6B are a front view and a side view, respectively, of the actuator 40 rotated 90° in the direction of the arrow AR (FIG. 5B). FIGS. 5A and 5B show the hand 6 facing downward. On the other hand, FIGS. 6A and 6B show the hand 6 facing sideways. In this way, the gripping portion 38 can be moved to any position by rotating the bracket 42 about the third rotation axis AX3, and the gripping portion 38 can be moved to any posture by rotating the connecting member 44 about the fourth rotation axis AX4.

[0052] The gripper 38 of the first embodiment shown in FIGS. 5A and 5B is a chuck device having a plurality of jaws 46 that can be opened and closed. In this embodiment, the gripper 38 has two jaws 46, but the number of jaws 46 may be three or more. Details of the jaws 46 will be described later. The gripper 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 gripper 38 coincide with each other. Here, the fifth axis AX5 is the gripping center of the gripper 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 horizontally offset from the third rotation axis AX3.

[0053] [Operation] Next, we will explain the operation of the component supply system SY including the component supply device 2. The workpieces W placed in the bowl 18 shown in Fig. 1 are transported in an aligned state by vibration on the spirally provided transport path 18a 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.

[0054] 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 the 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.

[0055] 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 the 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.

[0056] At this time, if the position and posture of the workpiece W detected in the sensing area 26 differ from the actual position and posture of the workpiece W in the pickup area 28, the hand 6 may not be able to pick it up. In this embodiment, the posture stabilization means 34 consisting of a groove suppresses changes in the position and posture of the workpiece W during transport, so the hand 6 can stably pick up the workpiece W.

[0057] 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.

[0058] Any 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, because the radially inner wall surface 34a of the groove 34 is inclined upward toward the inside in the radial direction, 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 again transported by vibration on the transport path 18a. Thereafter, the same operation is repeated.

[0059] [Hand claw structure] 7A to 9C, the structure of the claws 46 of the hand 6 of this embodiment will be described. As shown in Fig. 7A, the hand 6 has a plurality of claws 46 that grip or release the workpiece W, and a gripping unit 38 that moves the claws 46 in a gripping direction DR1 to grip the workpiece W and in a release direction DR2 to release the workpiece W.

[0060] The gripping unit 38 has a gripping mechanism 66 to which the claw 46 is attached and which moves in a gripping direction DR1 and a release direction DR2, and a first drive source 68 that moves the gripping mechanism 66 in the gripping direction DR1 and the release direction DR2. In detail, the gripping unit 38 has a box-shaped gripping unit main body 69, and the first drive source 68 is housed inside the gripping unit main body 69.

[0061] The gripping mechanism 66 is provided to protrude from the gripping body 69, and moves relative to the gripping body 69 in a gripping direction DR1 and a releasing direction DR2 by the power of the first drive source 68. In this embodiment, two gripping mechanisms 66 are provided. The number of gripping mechanisms 66 is not limited to this, and may be, for example, three or more.

[0062] In this embodiment, the gripping mechanism 66 closes (moves in the closing direction) to grip the workpiece W with the claws 46. That is, in this embodiment, the gripping direction DR1 for gripping the workpiece W is the closing direction, and the release direction DR2 for releasing the workpiece W is the opening direction. In the following description, the gripping direction DR1 is referred to as the closing direction DR1, the release direction DR2 is referred to as the opening direction DR2, and the "gripping direction and release direction" are referred to as the "opening / closing direction D1." Furthermore, the direction from the base end of the claws 46 supported by the gripping portion 38 toward the tip end where the gripping surface 52 is formed is referred to as the "extension direction D2." In other words, the extension direction D2 is the direction from the gripping portion 38 toward the workpiece W. Furthermore, the direction perpendicular to both the opening / closing direction D1 and the extension direction D2 (the left-right direction in FIG. 7B ) is referred to as the "orthogonal direction D3."

[0063] The first drive source 68 is, for example, an air cylinder driven by compressed air. However, the first drive source 68 is not limited to this and may be a hydraulic actuator, an electric motor, or the like. In this embodiment, one first drive source 68 drives two gripping mechanisms 66. However, a first drive source 68 may be provided for each gripping mechanism 66.

[0064] The hand 6 further includes a rotation transmission mechanism 70 that rotates the workpiece W. The rotation transmission mechanism 70 rotates the workpiece W gripped by the claws 46 about a rotation axis X1 that is parallel to the opening and closing direction. The rotation transmission mechanism 70 includes a rotating unit 72 that can rotate about the rotation axis X1 relative to the claws 46, and a second drive source 74 that drives the rotating unit 72 to rotate about the rotation axis X1.

[0065] The rotation transmission mechanism 70 further includes a power transmission mechanism 75 that transmits the power of the second drive source 74 to the rotating part 72, and an extendable rotation mechanism 76 that transmits the rotation of the second drive source 74 to the power transmission mechanism 75. In other words, the rotation of the second drive source 74 is transmitted to the rotating part 72 via the extendable rotation mechanism 76 and the power transmission mechanism 75.

[0066] In this embodiment, the second drive source 74 is a motor. The second drive source 74 is not limited to a motor, and may be, for example, a structure that uses a spring to rotate mechanically, a structure that uses air pressure such as an air cylinder, or a structure that uses hydraulic pressure such as a hydraulic actuator. When a motor is used as the second drive source 74, the posture of the workpiece W can be easily changed to any inclination compared to air pressure or hydraulic pressure.

[0067] Furthermore, the first drive source 68 and the second drive source 74 may have different structures, such as a structure in which the first drive source 68 uses air pressure and a structure in which the second drive source 74 uses electricity, or may have the same structure. Furthermore, in this embodiment, power from the second drive source 74 is supplied to only one of the two claws 46, but it may also be supplied to both.

[0068] The second drive source 74 is fixed to the gripping unit main body 69 of the gripping unit 38, and does not move in the opening / closing direction together with the gripping mechanism 66. Moreover, because the second drive source 74 does not move in the opening / closing direction together with the gripping mechanism 66 of the gripping unit 38, the load in the opening / closing direction is reduced. This allows the gripping mechanism 66 to operate at high speed. Furthermore, because the objects rotated by the power of the second drive source 74 are only the workpiece W and the rotating unit 72, the moment of inertia is reduced, allowing for high-speed rotation.

[0069] The rotating unit 72 is attached to each of the multiple claws 46 and moves in the opening and closing direction together with the claws 46. In this embodiment, the rotating unit 72 is provided at the tip of the claw 46. As shown in FIG. 8, the rotating unit 74 has a disk-shaped rotating unit main body 78 and a shaft 80 extending in the opening direction from the end face of the rotating unit main body 78. The center line of the rotating unit main body 78 and the central axis of the shaft 80 coincide with each other. Furthermore, the central axes of the pair of rotating units 74, 74 in this embodiment coincide with each other.

[0070] The rotating part 72 in this embodiment is made of metal. However, the material of the rotating part 72 is not limited to this and may be made of resin, for example. Furthermore, a rubber sheet, rubber bumps, or the like may be provided on the gripping surface 82 of the rotating part 72 that faces the closing direction of the rotating part main body 78. This makes it possible to prevent the workpiece W from slipping when gripping the workpiece W or when rotating the gripped workpiece W.

[0071] As shown in Fig. 8, a through hole 46a facing the opening / closing direction is provided at the tip of the claw portion 46. In this embodiment, the shaft body 80 of the rotating portion 72 is inserted into this through hole 46a via a rolling bearing 88. This allows the rotating portion 72 to be rotatably supported by the claw portion 46. The axis of the through hole 46a coincides with the central axis of the rotating portion 72. In other words, the axis of the through hole 46a coincides with the rotation axis X1 of the rotating portion 72. In this embodiment, a rolling bearing 88 is used, but a bearing other than a rolling bearing may be used, and a sliding bearing may also be used.

[0072] As shown in FIG. 7A , a power transmission mechanism 75 is connected to the tip of the shaft 80 of one of the rotating units 72. The power transmission mechanism 75 is connected to the rotating unit 72 and moves together with the rotating unit 72 in the gripping direction DR1 and the releasing direction DR2. A retaining member 89 is attached to the tip of the shaft 80 of the other rotating unit 72 to which the second drive source 74 is not connected. The retaining member 89 is, for example, a nut. In this embodiment, the power transmission mechanism 75 is connected to one of the rotating units 72; however, it is sufficient that the power transmission mechanism 75 is connected to at least one rotating unit 72, and the power transmission mechanism 75 may be connected to multiple rotating units 72.

[0073] In this embodiment, a belt-shaped endless power transmission member 90, specifically a timing belt, is used as the power transmission mechanism 75. The endless power transmission member 90 may also be a drive chain.

[0074] The timing belt 90 is provided between the telescopic rotation mechanism 76 and the rotating part 72. A primary pulley 92a and a secondary pulley 92b are arranged on the surface of the claw part 46 facing outward in the opening and closing direction. The timing belt 90 is wound around the primary pulley 92a and the secondary pulley 92b. The secondary pulley 92b is arranged coaxially with the rotation axis X1 of the rotating part 72 and is connected to the shaft body 80 of the rotating part 72.

[0075] The primary pulley 92a is connected to the telescopic rotation mechanism 76. The telescopic rotation mechanism 76 is disposed between the second drive source 74 and the power transmission mechanism 75 and is capable of extending and retracting in a gripping direction DR1 and a releasing direction DR2. In other words, the telescopic rotation mechanism 76 transmits the rotation of the second drive source 74 to the power transmission mechanism 75 and moves in the gripping direction DR1 and the releasing direction DR2 relative to the second drive source 74.

[0076] 9A, the telescopic rotation mechanism 76 has a first rotating shaft 94 connected to the output shaft 74a of the second drive source 74, a second rotating shaft 96 connected to a primary pulley 92a of the power transmission mechanism 75, and a telescopic rotation structure 98 provided between the first rotating shaft 94 and the second rotating shaft 96. That is, in this embodiment, the primary pulley 92a of the power transmission mechanism 75 constitutes an inlet rotating body of the power transmission mechanism 75 to which the second rotating shaft 96 is connected.

[0077] As shown in FIG. 9B, the telescopic rotation structure 98 transmits the rotation of the first rotation shaft 94 to the second rotation shaft 96 and supports the second rotation shaft 96 so that the second rotation shaft 96 can move relative to the first rotation shaft 94 in a gripping direction DR1 and a releasing direction DR2.

[0078] 9A, the telescopic rotation structure 98 has a cylindrical outer member 104, an inner member 106 inserted into a hollow hole 104c of the outer member 104, and rolling elements 108 interposed between the outer member 104 and the inner member 106. In this embodiment, the rolling elements 108 are eight spheres arranged in the circumferential direction. However, the shape and number of the rolling elements 108 are not limited to this.

[0079] In this embodiment, the outer member 104 is cylindrical with one end (the left end in FIG. 9C ) closed and the other end open, and the shaft end of the first rotating shaft 94 is connected to the bottom 104a on the one end side. In this embodiment, the first rotating shaft 94 and the outer member 104 are formed as an inseparable unit. In other words, the outer member 104 is provided on the shaft end of the first rotating shaft 94. That is, one end of the first rotating shaft 94 is connected to the rotating shaft 74a of the second driving source 74, and the other end is connected to the outer member 104. Therefore, the outer member 104 is rotatable around the axis X2 of the rotating shaft 74a of the second driving source 74 with respect to the gripping portion 38 ( FIG. 7A ).

[0080] 9C, grooves 104b extending in the axial direction are formed on the inner peripheral surface of the outer member 104. A plurality of grooves 104b are provided and aligned in the circumferential direction. In this embodiment, the number of grooves 104b provided is the same as the number of rolling elements 108, i.e., eight.

[0081] As shown in Fig. 9A, in this embodiment, the inner member 106 has a cylindrical shape, and one end face (the right end face in Fig. 9C) is connected to the shaft end portion of the second rotating shaft 96. In this embodiment, the second rotating shaft 96 and the inner member 106 are formed as an inseparable unit. In other words, the inner member 106 is provided on the shaft end portion of the second rotating shaft 96. A circumferential groove 106a extending in the circumferential direction is formed on the outer diameter surface of the axially intermediate portion of the inner member 106.

[0082] 9C, the outer diameter of the inner member 106 is set to be slightly smaller than the inner diameter of the outer member 104 and larger than the outer diameter of the second rotating shaft 96. Rolling elements 108 are disposed between the inner diameter surface of the outer member 104 and the outer diameter surface of the inner member 106. In other words, the rotation of the outer member 104 is transmitted to the inner member 106 via the rolling elements 108. In other words, the inner member 106 is rotatably connected to the outer member 104 via the rolling elements 108.

[0083] Specifically, the rolling elements 108 are disposed between the circumferential grooves 106a of the inner member 106 and the grooves 104b of the outer member 104. The rolling elements 108 are movable in the axial direction (opening / closing direction) along the grooves 104b of the outer member 104. In other words, the inner member 106 is rotatable around the axis X2 of the rotation shaft 74a of the second driving source 74 relative to the gripping part 38 (FIG. 7A), and is movable in a direction parallel to the opening / closing direction.

[0084] The other end of the second rotating shaft 96 is connected to the power transmission member 75 of the rotation transmission mechanism 70. In other words, one end of the second rotating shaft 96 is connected to the inner member 106, and is connected to the inlet rotating body (primary pulley) 92a of the power transmission mechanism 75 of the rotation transmission mechanism 70.

[0085] The first and second rotating shafts 94, 96, the outer member 104, and the inner member 106 may be made of metal or resin. A lubricant such as grease may be filled in the gap between the outer member 104 and the inner member 106. In this case, a seal member may be provided at the open end of the outer member 104 to prevent the grease from leaking to the outside.

[0086] By providing such an extendable rotation mechanism 76, in Fig. 9C, the first rotating shaft 94 and the outer member 104 rotate around the axis X2 of the rotating shaft 74a of the second drive source 74, and the second rotating shaft 96 and the inner member 106 rotate via the rolling elements 108. Furthermore, the second rotating shaft 96 and the inner member 106 move in a direction parallel to the opening and closing direction of the gripping mechanism 66 in Fig. 7A as the gripping mechanism 66 opens and closes. As a result, rotational power can be transmitted to the rotating portion 72 at the tip of the claw portion 46 even when the gripping mechanism 66 opens and closes.

[0087] In this embodiment, an outer member 104 is provided at the axial end of the first rotating shaft 94, and an inner member 106 is provided at the axial end of the second rotating shaft 96, but it is also possible to provide an inner member 106 at the axial end of the first rotating shaft 94, and an outer member 104 at the axial end of the second rotating shaft 96.

[0088] In this embodiment, the rotation transmission mechanism 70 and the claw portion 46 are integrated to form a sub-assembly. Specifically, the rotating portion 72, the claw portion 46, the power transmission mechanism 75, the telescopic rotation mechanism 76, and the second drive source 74 are integrated. This integrated sub-assembly is attached to the gripping portion 38. This allows the claw portion 46 having the rotation transmission mechanism 70 of this embodiment to be applied to existing gripping portions. In particular, it is highly versatile because it can easily be adapted to the size of the gripping mechanism 66 and the length of the claw portion 46.

[0089] In other words, in this embodiment, the rotation transmission mechanism 70 and the claw portion 46 form an integrated module. Specifically, the rotating portion 72, the claw portion 46, the timing belt 90, the pulleys 92a and 92b, the first and second rotating shafts 94 and 96, the outer member 104, the inner member 106, the rolling elements 108, and the second driving source 74 are modularized.

[0090] When the hand 6B grips the workpiece W, the first driving source 68 is driven to move the gripping mechanism 66 and the claws 46 fixed thereto in the gripping direction DR1. At this time, the second driving source 74 fixed to the gripping body 69 and the first rotation shaft 94 and outer member 104 of the telescopic rotation mechanism 76 connected to the second driving source 74 do not move in the gripping direction DR1.

[0091] Meanwhile, in the telescopic rotation mechanism 76, the inner member 106, which is connected to the outer member 104 via the rolling elements 108 so as to be movable in the opening and closing direction, and the second rotating shaft 96 move in the gripping direction DR1. Furthermore, the rotation transmission mechanism 70 connected to the second rotating shaft 96 and the rotating part 72 connected to the rotation transmission mechanism 70 also move in the gripping direction DR1.

[0092] 9C rotates when the second drive source 74 is driven while the hand 6 is gripping the workpiece W. When the outer member 104 rotates, the inner member 106 and the second rotation shaft 96 rotate via the rolling elements 108.

[0093] When the second rotating shaft 96 rotates, the upstream pulley 92a in Fig. 7A rotates, and this rotation is transmitted to the downstream pulley 92b via the timing belt 90, causing the downstream pulley 92b to rotate. When the downstream pulley 92b rotates, one of the rotating parts 72 connected thereto rotates, and this rotation is transmitted to the other rotating part 72 via the workpiece W, causing the other rotating part 72 to also rotate. In other words, the workpiece W rotates around the rotation axis X1. This allows the posture of the workpiece W to be changed.

[0094] When the hand 6B releases the workpiece W, the first drive source 68 is driven to move the gripping mechanism 66 and the claw portion 46 fixed thereto in the release direction DR2. At this time, similar to when gripping the workpiece W, the second drive source 74, the first rotation shaft 94 of the telescopic rotation mechanism 76, and the outer member 104 do not move in the release direction DR2, but the inner member 106 of the telescopic rotation mechanism 76, the second rotation shaft 96, and the rotating portion 72 move in the release direction DR2.

[0095] [Grip surface structure] 7A, 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 D1. The claws 46 extend from the gripping portion 38 in the extension direction D2, upward in the illustrated example, and have at their tip ends 46b gripping surfaces 52 that grip the workpiece W. In detail, the rotating portion 72 constitutes the gripping surface 52.

[0096] 10, 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 extension direction D2, at an incline in the opening direction, toward a tip end side (lower side in FIG. 9) in the extension direction D2, and a second inclined surface 56 that extends from an end 52b on the tip end side (lower side in FIG. 9) in the extension direction D2, at an incline in the opening direction, toward a base end side (upper side in FIG. 9) in the extension direction D2. 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.

[0097] 10, when viewed from the orthogonal direction D3, the edge of the inclined surface 52 (the edge in the orthogonal direction) is V-shaped and 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 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."

[0098] When viewed from the orthogonal direction D3, the angle formed by the imaginary line V1 on the tip side extending the second inclined surface 56 toward the tip side (the lower side in FIG. 10) and the horizontal conveying surface 22a of the conveying table 8 is defined as the tip side angle α. When viewed from the orthogonal direction D3, the angle formed by the imaginary line V2 on the base side extending the first inclined surface 54 toward the base side (the upper side in FIG. 10) and the parallel line LN parallel to the conveying surface 22a is defined as the base side angle β. Furthermore, the angle formed by 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.

[0099] Furthermore, in this embodiment, the distal angle α is set to be equal to or greater than 25° and equal to or less than 30° (25°≦α≦30°), while the proximal angle β is set to be greater than 50° and smaller than 60° (50°<β<60°). However, the distal angle α and the proximal angle β are not limited to these values.

[0100] In this embodiment, the tip side angle α is set smaller than the base side angle β (α<β), but depending on the shape of the workpiece, the tip side angle α and the base side angle β may be set to be the same (α=β), or the tip side angle α may be set larger than the base side angle β (α>β).

[0101] The base end 52a and the tip end 52b of the claw 46, i.e., the base end and tip end corners 52a, 52b of the claw 46, are rounded. In other words, the base end and tip end corners 52a, 52b of the claw 46 have an R shape. This prevents the corners 52a, 52b of the claw 46 from scratching the workpiece W. In this embodiment, both the base end corner 52a and the tip end corner 52b are rounded, but only the tip end corner 52b may be rounded.

[0102] Furthermore, the surface 58 (the underside 58 of the claw 46 in FIG. 10) that forms the corner portion 52b on the tip side and does not come into contact with the workpiece W is configured to be parallel to the conveying surface 22a when the extension direction D2 of the gripping portion 38 is perpendicular to the horizontal conveying surface 22a of the conveying table 8. Alternatively, the underside 58 of the claw 46 may be inclined so that the corner portion 52b on the tip side becomes the lower end with respect to the conveying surface 22a. This makes it possible to prevent interference between the underside 58 of the claw 46 and the conveying table 8.

[0103] 11A and 11B show modified examples of the claw portion 46 of the present embodiment. In the example of Fig. 11A and Fig. 11B, a sliding member 60 is attached to the first inclined surface 54 and the second inclined surface 56 of the claw portion 46.

[0104] The sliding member 60 is made of a material that has high slidability but 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 to achieve high slidability. Examples of materials for the sliding member 60 include polyoxymethylene (POM) and monomer cast nylon (MC nylon). However, the material for the sliding member 60 is not limited to these. By providing the sliding member 60, it is possible to prevent the workpiece W from being damaged. Furthermore, by setting the friction coefficient to 0.2 or less, the workpiece W can move easily along the inclined surfaces 54, 56, and the cylindrical workpiece W that is slightly inclined relative to the conveyance table 8 can be held in a stable position where the four surfaces 54, 56 are tangent to each other.

[0105] In the example shown in FIGS. 11A and 11B, the sliding member 60 is attached to both the first and second inclined surfaces 54, 56. However, 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, which is more 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 in 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. Making only the sliding member 60 replaceable is less expensive than replacing the entire claw portion 46, and maintenance costs can be reduced.

[0106] In this embodiment, the coefficient of friction of the surface of the sliding member 60 is set to 0.2 or less to obtain high slidability, but for example, the coefficient of friction of the surface of the sliding member 60 may be set to be smaller than the coefficient of friction of the surfaces of the claw portion 46 other than the inclined surfaces 54, 56. Furthermore, instead of attaching the sliding member 60, the coefficient of friction may be reduced by applying a surface treatment such as coating or polishing to the inclined surfaces 54, 56.

[0107] 12A to 12C and 13A to 13C, the effects of the first and second inclined surfaces 54, 56 will be described. Figures 12A to 12C show the state before the bolt-shaped workpiece W is picked up by the hand 6, and Figures 13A to 13C show the state after the bolt-shaped workpiece W has been picked up by the hand 6. Note that the second drive source 74, the power transmission mechanism 75, and the telescopic rotation mechanism 76 are omitted from Figures 12A to 12C and 13A to 13C.

[0108] In the component supply system 2 of this embodiment, due to a change in the model number of a product produced on the production line, there are cases where workpieces W having a different shape from those input before the change are input, or where workpieces W of different shapes are input simultaneously into the component 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 during a setup change or input simultaneously.

[0109] Because the outer diameter of the head of a bolt is larger than the outer diameter of the shank, the bolt is placed at a slight angle relative to the horizontal conveying surface 22a. However, with an actuator 40 (FIG. 5A) that uses compressed air or the like, the operating angle cannot be adjusted automatically, and manual adjustment takes time. While an electric actuator can adjust the angle, this increases costs and complicates control. Therefore, it is desirable to be able to pick up both workpieces W that are inclined relative to the conveying surface 22a and workpieces W that are horizontal without changing the operating angle of the actuator 40.

[0110] It is possible to grip the workpiece W by increasing the gripping force of the gripping portion 38, but this would result in 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 would also reduce the workpiece transport weight of the robot 4 (FIG. 1). Furthermore, the rigidity of the claw portion 46 needs to be increased in accordance with the gripping force of the gripping portion 38, which would make the claw portion 46 expensive.

[0111] 12A, 12B, and 12C, when picking up a bolt-shaped workpiece W that is placed at an angle with respect to the conveying surface 22a from above in the radial direction, the hand 6 of this embodiment picks up the workpiece W by scooping it up with the corners 52b on the tip sides of the claws 46. At this time, because the tip side angle α is small, even a workpiece W that is at an angle with respect to the conveying surface 22a can be easily picked up.

[0112] Furthermore, since the base end angle β is set to an appropriate value, as shown in Fig. 13C, the cylindrical workpiece W can easily follow the four inclined surfaces 54, 56. As a result, as shown in Fig. 13B, the workpiece W can be picked up in a horizontally stable position.

[0113] Furthermore, the rotating portion 72 shown in FIG. 8A allows the workpiece W gripped by the claw portion 46 to rotate around the rotation axis X1 parallel to the opening / closing direction D2, so that the workpiece W can be moved or placed stably regardless of the posture of the workpiece W at the time of pickup.

[0114] [Action and effect] 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 workpiece W pick-up operation by the robot 4. As a result, work efficiency is improved.

[0115] In particular, the position and posture of the workpiece W are 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 have 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 prevents the position and posture of the workpiece W from changing, so 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, improving work efficiency.

[0116] 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.

[0117] Furthermore, because the position and posture of the gripping portion 38 of the hand 6 can be changed, the hand 6 can be prevented from coming into contact with other workpieces W or equipment when picking up a workpiece W on the transport table 8. As a result, malfunctions in the hand 6 or other equipment can be prevented, and work efficiency is improved.

[0118] As described above, in the above embodiment, the gripping portion 38 of the hand 6 can approach the workpiece W at various angles, i.e., in the optimal position and posture. For example, the workpiece W may be picked up in the downward position as shown in FIGS. 5A and 5B, and then placed down in a horizontal position as shown in FIGS. 6A and 6B. Alternatively, the workpiece W may be picked up in the horizontal position as shown in FIGS. 6A and 6B, and then placed down in a downward position as shown in FIGS. 5A and 5B. Alternatively, the pick-up and placement postures may be the same, i.e., both may be downward or both may be horizontal. In this way, the posture can be freely changed, which prevents the hand 6 from interfering with peripheral equipment, other workpieces, etc.

[0119] A component supplying device 2 having a disk-shaped conveying table 8 can save space compared to a linear conveying table, but the hand is more likely to come into contact with parts 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 parts of the component supplying device 2.

[0120] In the above embodiment, the component supply device 2 has a standing wall 20 between the vibrating bowl feeder 16 and the conveyance table 8 that protrudes above the conveyance 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 the hand 6 can be prevented from coming into contact with the standing wall 20 of the component supply device 2 when picking up a workpiece W on the conveyance table 8.

[0121] As shown in FIG. 10 , by reducing the tip-side angle α of the claw 46, it becomes easier to pick up a workpiece W that is slightly tilted relative to the conveyance table 8. Furthermore, by increasing the base-side angle β, the inclination angle γ between the first inclined surface 54 and the second inclined surface 56 increases. This brings the tangents between the four inclined surfaces 54, 56 of the claw 46 and the cylindrical workpiece W closer to the connecting portion 55 between the first inclined surface 54 and the second inclined surface 56. Therefore, even if the diameter of the cylindrical workpiece W increases, it can be picked up so that the four inclined surfaces 54, 56 form tangent planes. Therefore, cylindrical workpieces W with different diameters can be stably picked up. In this way, not only cylindrical workpieces W placed horizontally relative to the conveyance table 8, but also cylindrical workpieces W that are slightly tilted relative to the conveyance table 8 and cylindrical workpieces W with different diameters can be stably picked up.

[0122] 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 less than 60°. That is, the settings are 25°≦α≦30° and 50°<β<60°. If the tip side angle α is less than 25°, the tip side corner 52b becomes thin, reducing the rigidity of the tip of the claw portion 46. Furthermore, if the tip side angle α exceeds 30°, it becomes difficult to pick up a workpiece W that is slightly tilted relative 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. Simulations have confirmed that setting the base side angle β to be greater than 50° and less than 60° allows for stable pickup of cylindrical workpieces W with desired outer diameters. In other words, setting the base side angle β to 50°<β<60° allows for stable pickup of cylindrical workpieces W with various outer diameters.

[0123] In this embodiment, the corner 52a on the base end side and the corner 52b on the tip end side of the claw portion 46 have an R shape. This configuration makes it possible to prevent the corners 52a, 52b from damaging the workpiece W. Note that the R shape may be provided only on the corner 52b on the tip end side, which is likely to come into contact with the workpiece W.

[0124] In this embodiment, the lower surface 58 of the claw 46 extends parallel to the conveying surface 22a of the conveying table 8. This configuration makes it possible to prevent the claw 46 from interfering with the conveying table 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 pickup. This also makes it possible to prevent the claw 46 from interfering with the conveying table 8.

[0125] In this embodiment, as shown in Figures 11A and 11B, a sliding member 60 may be attached to the inclined surfaces 54, 56 of the claw portion 46. This configuration makes it possible to prevent the workpiece W from being damaged by contact with the claw portion 46 during pickup. In this case, the sliding member 60 may be detachably attached to the inclined surfaces 54, 56 of the claw portion 46. This allows only the sliding member 60 to be replaced instead of the entire claw portion 46, making maintenance easier and reducing maintenance costs.

[0126] Furthermore, in general, a hand 6 having two jaws 46 needs to change the size of the gripping unit 38 itself, the opening / closing stroke, the length of the jaws 46, and the like, depending on the size of the workpiece W to be gripped. According to the configuration of the above embodiment, as shown in FIG. 7A , a rotating unit 72 of a rotation transmission mechanism 70 is separately provided at the tip of the jaws 46 attached to the gripping mechanism 66 of the gripping unit 38. The rotating unit 72 rotates the workpiece W around a rotation axis X1 parallel to the gripping direction DR1 and the release direction DR2 of the jaws 46. The gripping mechanism 66 moves using the power of a first driving source 68, and the rotating unit 72 rotates using the power of a second driving source 74. In other words, the gripping mechanism 66 and the rotating unit 72 are provided independently. As a result, even if the height of the workpiece W to be gripped changes during a setup change, it is sufficient to replace the jaws 46 and the rotation transmission mechanism 70 supported thereon, and there is no need to change the gripping unit 38. As a result, the length from the base of the claw portion 46 to the rotation shaft of the second drive source 74 can be easily changed.

[0127] In addition, the second drive source 74 does not move in the opening / closing direction together with the gripping mechanism 66 of the gripping unit 38. This reduces the load in the opening / closing direction, allowing the gripping mechanism 66 to operate at high speed. Furthermore, because only the rotating unit 72 is rotated, rather than the entire gripping unit 38, the only objects that rotate are the workpiece W and the rotating unit 72, reducing the weight and moment of inertia of the rotating objects. As a result, high-speed rotation of the rotating unit 72 and low torque of the second drive source 74 are possible, allowing the second drive source 74 to be made smaller and lighter.

[0128] According to the above configuration, after gripping the workpiece W, the workpiece W can be rotated by the rotating unit 72, thereby turning the workpiece W upside down without having to grip it again. This reduces the transport time. In addition, a temporary table for changing the position of the workpiece W is no longer necessary, which also saves space.

[0129] Furthermore, since the workpiece W is rotated by the rotating portion 72 installed at the tip of the claw portion 46 shown in Fig. 7A, the moment of inertia is smaller than when the entire claw portion 46 including the gripping mechanism 66 is rotated. Therefore, the workpiece W can be rotated at a higher speed.

[0130] In this embodiment, the rotation transmission mechanism 70 and the claw portion 46 are integrated to form a sub-assembly, and this sub-assembly is attached to the gripping portion 38. Specifically, the rotating portion 72, the claw portion 46, the power transmission mechanism 75, the telescopic rotation mechanism 76, and the second drive source 74 are integrated. With this configuration, the claw portion 46 having the rotation transmission mechanism 70 can be applied to existing gripping portions. In particular, it is highly versatile because it can easily be adapted to the size of the gripping mechanism 66 and the length of the claw portion 46.

[0131] In this embodiment, the telescopic rotation mechanism 76 includes a first rotating shaft 94 connected to the output shaft 74a of the second drive source 74, a second rotating shaft 96 connected to the inlet rotating body 92a of the power transmission mechanism 75, and a telescopic rotation structure 98 that transmits rotation of the first rotating shaft 94 to the second rotating shaft 96. The telescopic rotation structure 98 supports the second rotating shaft 96 so that it can move in the opening and closing direction relative to the first rotating shaft 94. Specifically, the telescopic rotation structure 98 includes a cylindrical outer member 104 provided at the axial end of the first rotating shaft 94, an inner member 106 provided at the axial end of the second rotating shaft 96 and inserted into a hollow hole in the outer member 104, and rolling elements 108 interposed between the outer member 104 and the inner member 106. The rolling elements 108 transmit the rotation of the outer member 104 to the inner member 106, and support the inner member 106 so that it can move in the opening and closing direction relative to the outer member 104. With this configuration, rotational torque can be reliably transmitted in the rotational direction, and smooth movement can be achieved with little resistance in the extension and retraction direction.

[0132] In this embodiment, the second drive source 74 is an electric motor. By configuring the second drive source 74 as an electric motor, the posture of the workpiece W can be easily changed to any inclination. Not only can the workpiece W be turned over, but the inclination of the workpiece W can also be freely changed. This makes it possible to accommodate cases where it is better for the angle of the claw portion 46 to be inclined at a predetermined angle relative to the workpiece W, such as when the workpiece W is transported at an angle rather than flat, or when the workpiece W has a notch for gripping. Furthermore, it is easy to accommodate cases where the workpiece W must be placed at a predetermined angle after being gripped.

[0133] In this embodiment, the power transmission mechanism 75 has a timing belt 90. With this configuration, the length from the second drive source 74 to the rotating unit 72 can be easily changed, which increases the degree of freedom in arranging the second drive source 74.

[0134] 7A, the second drive source 74 is fixed to the gripping body 69, but the second drive source 74 may be provided to the claw portion 46. In this case, the load in the opening and closing direction increases by the amount of the second drive source 74, but since the second drive source 74 can be directly connected to the rotating body 72, the extension and contraction rotation mechanism 76 and the power transmission mechanism 75 can be omitted.

[0135] Figure 14 shows a modified example of the telescopic rotation structure 98A of the telescopic rotation mechanism 76A. The telescopic rotation structure 98A of the telescopic rotation mechanism 76A shown in Figure 14 has a first gear 110 provided on the first rotating shaft 94 and having a long axial dimension, and a second gear 112 provided on the second rotating shaft 96 and having a shorter axial dimension than the first rotating shaft 110.

[0136] The axial dimension of the first gear 110 is set longer than the opening / closing width of the gripping mechanism 66 (FIG. 7A), i.e., the amount of movement in the opening / closing direction. The first rotating shaft 94 and the first gear 110 are rotatable around the rotation axis of the second driving source 74 relative to the gripping unit main body 69 (FIG. 7A). Furthermore, the first rotating shaft 94 and the first gear 110 do not move in the opening / closing direction.

[0137] When the second gear 112 meshes with the first gear 110, the rotation of the first gear 110 is transmitted to the second gear 112 and the second rotating shaft 96, and the second gear 112 and the second rotating shaft 96 can move in the opening and closing direction (axial direction).

[0138] With this configuration, rotation of the second drive source 74 causes the first rotating shaft 94 and the first gear 110 to rotate about their respective rotation axes, and meshing of the gears 110, 112 causes the second gear 112 and the second rotating shaft 96 to rotate. Furthermore, as the gripping mechanism 66 of FIG. 7A opens and closes, meshing of the first and second gears 110, 112 causes the second gear 112 and the second rotating shaft 96 to move in a direction parallel to the opening and closing direction. Therefore, even when the gripping mechanism 66 opens and closes, rotational power can be transmitted to the rotating portion 72 at the tip of the claw portion 46. Thus, with a small number of parts, the modified example of FIG. 14 can reliably transmit rotational torque in the rotational direction and is movable in the extension and retraction direction.

[0139] In Figure 14, a first gear 110 with a long axial dimension is provided on the first rotating shaft 94, and a second gear 112 is provided on the second rotating shaft 96, but it is also possible to provide a first gear 110 with a long axial dimension on the second rotating shaft 96, and a second gear 112 on the first rotating shaft 94.

[0140] Fig. 15 shows a gripping device (hand) 6A according to a modified example of this embodiment. In the modified example of Fig. 15, a power transmission mechanism 75 has a rod 115 with bevel gears 114 attached to both ends. The bevel gears 114 may be "straight gears" or "helical gears."

[0141] A rod 115 extends between the rotation axis X2 of the second drive source 74 and the rotation axis X1 of the rotating unit 72 in a direction perpendicular to both axes X1 and X2. The bevel gear 114 has a primary bevel gear 114a on the second drive source 36 side and a secondary bevel gear 114b on the rotating unit 34 side.

[0142] A drive-side bevel gear 116 is provided at the tip of the second rotation shaft 96 of the telescopic rotation mechanism 76, and the drive-side bevel gear 116 meshes with the primary bevel gear 114a. The drive-side bevel gear 116 is disposed coaxially with the rotation axis X2 of the second drive source 74, and the rotation of the second drive source 74 is transmitted via the telescopic rotation mechanism 76. In other words, in the first modified example, the primary bevel gear 114a constitutes an inlet rotor of the power transmission mechanism 75 to which the second rotation shaft 96 of the telescopic rotation mechanism 76 is connected.

[0143] A driven bevel gear 118 is provided at the tip of the shaft 80 of the rotating part 72, and the driven bevel gear 118 meshes with the secondary bevel gear 114b. The driven bevel gear 118 is disposed coaxially with the rotation axis X1 of the rotating part 72, and the rotation of the second driving source 74 is transmitted to the driven bevel gear 118 via the rotation transmission mechanism 70. In this way, the power of the second driving source 74 is transmitted to the rotating part 72.

[0144] In the modified example of Figure 15, by using a rod 115 with bevel gears 114 at both ends as the power transmission mechanism 75, the length from the second driving source 74 to the rotating part 72 can be easily changed, thereby increasing the degree of freedom in the placement of the second driving source 74.

[0145] 16A and 16B show a gripping device (hand) 6B according to another modified example of this embodiment. In the example of FIGS. 7A and 7B, the output shaft 74a of the second driving source 74 and the first rotation shaft 94 of the telescopic rotation mechanism 76 are directly connected, and the telescopic rotation mechanism 76 is disposed coaxially with the rotation axis X2 of the second driving source 74. However, in the modified example of FIGS. 16A and 16B, the output shaft 74a of the second driving source 74 and the first rotation shaft 94 of the telescopic rotation mechanism 76 are connected via a belt 120 and a pair of pulleys 122, 122. In other words, the rotation axis X2 of the second driving source 74 and the rotation axis X3 of the telescopic rotation mechanism 76 do not coincide with each other.

[0146] In detail, one pulley 122 is provided on the output shaft 74a of the second drive source 74, and the other pulley 122 is provided on the first rotation shaft 94 of the telescopic rotation mechanism 76, with a belt 120 stretched across both pulleys 122, 122. This allows the rotation of the second drive source 74 to be transmitted to the telescopic rotation mechanism 76. The rest of the structure is the same as the example in Figures 7A and 7B.

[0147] 16A and 16B, the dimension of the gripper body 69 of the gripper 38 in the opening / closing direction can be reduced compared to the configuration in which the telescopic rotation mechanism 76 and the second drive source 74 are installed coaxially as in FIGS. 7A and 7B. This makes it possible to prevent the hand 6B from interfering with surrounding objects. In the modification in FIGS. 16A and 16B, the second drive source 74 and the telescopic rotation mechanism 76 are connected by a combination of a pulley 122 and a belt 120, but a combination of a sprocket and a chain, or a combination of multiple gears, may also be used.

[0148] 7A and 7B and the example of FIGS. 16A and 16B, a structure combining a belt 90 and a pulley 92 is used as the power transmission member 75, and the example of FIG. 15 uses a structure combining a bevel gear 114 and a rod 115, but a structure combining multiple spur gears may also be used as the power transmission mechanism 75.

[0149] The present invention is not limited to the above-described embodiments, and various additions, modifications, and omissions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and omissions are also included in the scope of the present invention. [Explanation of symbols]

[0150] 6,6A,6B hand 38 Gripping part 46 Claw 52 Gripping surface 54 First Inclined Surface 56 Second Inclined Surface 70 Rotational transmission mechanism 72 Rotating part 74 Second driving source 75 Power transmission mechanism 76 Telescopic rotation mechanism 94 First Rotation Axis 96 Second Rotation Axis 98 Telescopic Rotating Structure 104 Outer member 106 Inner member 108 rolling elements 110 First Gear 112 Second Gear α Tip side angle β proximal angle D1 Opening and closing direction D2 Extending direction D3 Orthogonal direction double work

Claims

1. A plurality of jaws for gripping or releasing a workpiece; a gripping unit that moves the claws in a gripping direction to grip the workpiece and in a release direction to release the workpiece; a rotation transmission mechanism that rotates the workpiece gripped by the claw portion around a rotation axis that is parallel to the gripping direction and the release direction, The claw portion is supported at its base end by the gripping portion so as to be movable in the gripping direction and the release direction, has a gripping surface at its tip end that grips the workpiece, and extends in an extension direction from the base end to the tip end, The gripping surface is a first inclined surface extending from an end portion on a base end side in the extension direction toward a tip end side in the extension direction at an incline in the release direction; a second inclined surface extending from an end portion on the distal end side in the extension direction toward a base end side in the extension direction at an incline in the release direction; A hand that has

2. 2. The hand according to claim 1, wherein, when viewed from a direction perpendicular to the extension 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.

3. 2. The hand according to claim 1, wherein, when viewed from a direction perpendicular to the extension 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 larger 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.

4. 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.

5. The hand according to any one of claims 1 to 3, The rotation transmission mechanism includes: a rotating portion provided at a tip of the claw portion and rotatable about a rotation axis parallel to the opening and closing direction relative to the claw portion; a second drive source that drives the rotating portion to rotate around the rotation axis, A hand in which the gripping surface is formed on the rotating part.

6. 6. The hand according to claim 5, wherein the rotation transmission mechanism and the claw portion are integrated to form a sub-assembly, The sub-assembly is attached to the gripping portion of the hand.

7. The hand according to claim 5, The rotation transmission mechanism further includes: a power transmission mechanism connected to at least one of the rotating parts, moving together with the rotating part in the gripping direction and the releasing direction, and transmitting power of the second drive source to the rotating part; an extendable rotation mechanism that is extendable in the gripping direction and the releasing direction and that transmits rotation of the second drive source to the power transmission mechanism; A hand that has

8. 8. The hand according to claim 7, wherein the telescopic rotation mechanism comprises: a first rotary shaft connected to an output shaft of the second drive source; a second rotary shaft coupled to an inlet rotary body of the power transmission mechanism; a telescopic rotation structure that transmits rotation of the first rotation shaft to the second rotation shaft and supports the second rotation shaft so that the second rotation shaft is movable relative to the first rotation shaft in the gripping direction and the release direction.

9. 9. The hand according to claim 8, wherein the telescopic rotating structure is a cylindrical outer member provided at one shaft end of the first rotary shaft and the second rotary shaft; an inner member provided at the other shaft end of the first rotary shaft and the second rotary shaft and inserted into the hollow hole of the outer member; a rolling element interposed between the outer member and the inner member, transmitting rotation of the outer member to the inner member, and supporting a member provided on the second rotating shaft movably in the gripping direction and the releasing direction relative to a member provided on the first rotating shaft; A hand that has

10. 9. The hand according to claim 8, wherein the telescopic rotating structure is a first gear provided on one of the first rotation shaft and the second rotation shaft, the first gear having an axial dimension longer than an opening / closing width of the gripping mechanism; a second gear provided on the other of the first rotation shaft and the second rotation shaft, meshing with the first gear to transmit rotation of the first gear, and movable in the gripping direction and the release direction relative to the first gear; A hand that has

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