Gripping device
The gripping device addresses the bulkiness and inefficiency of conventional designs by allowing independent control of gripping jaws through a novel mechanism, resulting in a lighter, more compact, and high-speed operation capable of adjusting angles and avoiding interference.
Patent Information
- Application Number
- JP2024083458
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-05-22
- Publication Date
- 2025-12-05
AI Technical Summary
Conventional gripping devices for workpieces, such as those described in Patent Documents 1 and 2, are heavy and large due to mechanisms that distribute power from a single drive source to both gripping jaws or require independent mechanisms for simultaneous operation, making them cumbersome and inefficient.
A gripping device with a gripping jaw unit that operates in an opening and closing direction, supported to rotate around a parallel axis, utilizing an opening/closing drive source and a rotation drive source to independently control the gripping jaws, eliminating the need for power distribution mechanisms, and allowing the jaws to oscillate and rotate independently.
The device is lighter, more compact, and capable of high-speed operation by reducing the weight and moment of inertia of the rotating components, enabling easier angle adjustments and interference avoidance in tight spaces.
Smart Images
Figure 2025177000000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a gripping device that grips a workpiece such as a mechanical part or an electronic part. [Background technology]
[0002] In a hand installed at the tip of an articulated robot or the like, the claws are opened and closed in a linear direction to grasp a workpiece, and the posture of the workpiece can be changed while it is being grasped by the claws (for example, Patent Documents 1 and 2).
[0003] The hand of Patent Document 1 has a rotatable nut attached to a shaft extending in the opening and closing direction of the gripping jaws, and rotation is transmitted to the gripping jaws via this nut, causing the gripping jaws to swing while gripping a workpiece.The hand of Patent Document 2 has a nut threaded onto a ball screw extending in the opening and closing direction of the gripping jaws, and rotation is transmitted to the gripping jaws via this nut, causing the jaws to swing while gripping a workpiece. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Patent No. 5617512 [Patent Document 2] Patent No. 6029561 Summary of the Invention [Problem to be solved by the invention]
[0005] In the hands of Patent Documents 1 and 2, the gripping jaws can be adjusted to a direction that makes it easier to grip the workpiece before gripping it. This adjustment is effective when gripping workpieces that are stacked irregularly. In order to grip the workpiece, the angles of the pair of gripping jaws must move in sync. In conventional structures, a mechanism is installed that distributes power from a single drive source to both gripping jaws, or independent mechanisms are driven simultaneously to operate the pair of gripping jaws simultaneously. In this case, the hand becomes heavy and large.
[0006] An object of the present invention is to provide a gripping device that can be made lighter and more compact than conventional structures. [Means for solving the problem]
[0007] The gripping device of the present invention comprises: a gripping jaw unit that operates in an opening and closing direction to grip and release a workpiece; a gripping mechanism that supports the gripping jaw unit so as to be movable in the opening and closing direction and rotates around a rotation axis that is parallel to the opening and closing direction; an opening / closing drive source that drives the gripping jaw unit to open and close; a rotation drive source that rotates the gripping jaw unit around the rotation axis, The gripping claw unit has a pair of gripping claws and a gripping claw connecting mechanism that connects a part of the gripping claws, The gripping mechanism includes: a swing rotation shaft that supports one or both of the gripping jaws and rotatably supports the entire gripping jaw unit so that the gripping jaw unit can swing about the rotation axis; an opening / closing mechanism including a linear motion element that moves the pair of gripping claws in the opening / closing direction, The pair of gripping jaws are driven to open and close by the opening / closing drive source in cooperation with the linear motion element and the swing rotation shaft.
[0008] With this configuration, the gripping jaw unit can be oscillated and rotated while the pair of gripping jaws grips the workpiece. Therefore, the workpiece can be oscillated and rotated without operating the work machine to which this gripping device is connected. Because the main objects of rotation are the workpiece and the gripping jaws, the weight and moment of inertia of the objects of rotation are reduced. As a result, the work machine can rotate at high speeds.
[0009] The oscillating rotation shaft supports one or both gripping jaws and rotatably supports the entire gripping jaw unit, and the gripping jaw unit is rotationally driven by a rotation drive source. The pair of gripping jaws are driven to open and close by the opening and closing drive source, with the linear motion element and the oscillating rotation shaft working together. This eliminates the need for a mechanism that distributes rotational power from a single drive source to both gripping jaws, or a drive source that simultaneously rotates independent mechanisms, as in the conventional structure described above, and allows the entire gripping device to have a simpler structure than the conventional structure. This allows the gripping device to be lighter and more compact than the conventional structure.
[0010] The gripping mechanism may include a rotation mechanism that rotatably supports the gripping jaw unit about the rotation axis, and this rotation mechanism may have an extension / retraction rotation mechanism that transmits the rotation of the rotation drive source to the swing rotation shaft and enables the swing rotation shaft to move in the opening / closing direction. In this case, rotation can be transmitted while the gripping jaw unit is moving in the opening / closing direction, while stopped at two points before and after the extension / retraction movement, and at any point during the extension / retraction movement.
[0011] The rotation drive source may be a motor, in which case the orientation of the workpiece can be easily changed to any desired inclination.
[0012] The swing rotation shaft may be provided with a gripper jaw attaching / detaching member that detachably supports one of the gripper jaw units, in which case the gripper jaw unit can be easily replaced depending on the shape of the workpiece, the conditions of use of the gripping device, etc.
[0013] the gripping claw coupling mechanism has a restoring force that allows one of the gripping claws to be elastically deformed relative to the other gripping claw; a pressing member that abuts against and separates from the other gripping claw is provided at a portion of the linear motion element that faces the other gripping claw; The linear motion element is moved in one of the opening and closing directions by the opening and closing drive source, thereby causing the pressing member to abut against the other gripping claw against the restoring force, thereby bringing the pair of gripping claws into a closed state; The pair of gripping claws may be brought into an open state by the restoring force when the linear motion element is moved in the other opening / closing direction by the opening / closing drive source.
[0014] In this case, for example, ordinary tweezers can be retrofitted as a pair of gripping jaws having the gripping jaw connection mechanism with the restoring force. This allows the approach angle to the workpiece to be changed using only the tip of the gripping device, for example, when picking bulk items, and makes it possible to avoid interference between the gripping device and work machines such as robots in extremely small spaces. Furthermore, retrofitting tweezers reduces the manufacturing cost of the gripping device compared to designing a new dedicated gripping jaw unit.
[0015] The gripping claw unit may have a passive rotation shaft that rotatably supports the other gripping claw on the gripping mechanism. In this case, one gripping claw is rotatably supported on the swingable rotation shaft, and the other gripping claw is rotatably supported on the gripping mechanism via the passive rotation shaft. In this way, since the pair of gripping claws are rotatably supported on the gripping mechanism, the rigidity of the gripping claw unit can be increased and undesired tilting of the gripping claws, misalignment of the open / closed positions, etc. can be prevented.
[0016] The telescopic rotation mechanism is an input shaft to which rotation of the rotation drive source is transmitted and which is rotatably supported about the rotation axis; an output shaft that is rotatably supported parallel to the input shaft; a first gear provided on the input shaft; a second gear that is provided on the output shaft and meshes with the first gear to transmit a rotational force of the first gear, and that is movable in an axial direction parallel to the opening / closing direction relative to the first gear, Either one of the first and second gears may have an axial dimension longer than the opening / closing width of the gripping mechanism. In this case, with a small number of parts, rotational torque can be reliably transmitted from the input shaft to the output shaft, and the output shaft can be moved in the extension / contraction direction, which is the axial direction.
[0017] The telescopic rotation mechanism may have a sliding bearing that supports the output shaft so that it can slide in the axial direction. In this case, the rotation of the output shaft can be maintained while the output shaft slides in the axial direction with a simple structure. Furthermore, the output shaft is less likely to wear than in a structure without a sliding bearing, which improves the durability of the telescopic rotation mechanism.
[0018] The power transmission mechanism of the rotation mechanism may be a combination of pulleys and a belt. In this case, the rotation speed of the oscillating rotation shaft and the distance between the input and output shafts can be adjusted by changing the diameter of the pulleys and the length of the belt. This increases the degree of freedom in the capacity and arrangement of the rotation drive source.
[0019] The power transmission mechanism of the rotation mechanism may be a spur gear. In this case, the rotation speed of the oscillating rotation shaft and the distance between the input and output shafts can be adjusted by changing the diameter and number of teeth of the spur gear. This increases the degree of freedom in the capacity and arrangement of the rotation drive source.
[0020] The gripping mechanism may have a detachable connecting part at the tip of the working machine. In this case, it is easy to replace the opening / closing mechanism with one having a different opening / closing stroke, for example, depending on the application of the working machine, the work, etc., thereby reducing the amount of work required. [Effects of the Invention]
[0021] The gripping device of the present invention includes a gripping jaw unit that operates in an opening and closing direction to grip and release a workpiece, a gripping mechanism that supports the gripping jaw unit so that it can move in the opening and closing direction and rotates about a rotation axis parallel to the opening and closing direction, an opening / closing drive source that drives the gripping jaw unit to open and close, and a rotation drive source that drives the gripping jaw unit to rotate about the rotation axis, the gripping jaw unit having a pair of gripping jaws and a gripping jaw coupling mechanism that connects a portion of the gripping jaws, the gripping mechanism including a swing rotation shaft that supports one or both of the gripping jaws and rotatably supports the entire gripping jaw unit so that it can swing about the rotation axis, and an opening / closing mechanism including a linear motion element that moves the pair of gripping jaws in the opening and closing direction, and the linear motion element and the swing rotation shaft cooperate to drive the pair of gripping jaws to open and close by the opening / closing drive source, thereby achieving a lighter and more compact structure than conventional structures. [Brief explanation of the drawings]
[0022] [Figure 1] 1 is a perspective view of a gripping device according to a first embodiment of the present invention. [Figure 2A] FIG. [Figure 2B] FIG. 10 is a front view showing a modified example of the rotation mechanism of the gripping device. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 2 is a front view of a rotation drive source and an extension / retraction rotation mechanism of the gripping device. [Figure 6] FIG. 2 is a left side view of the rotation drive source and the telescopic rotation mechanism. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. [Figure 8] FIG. 2 is a perspective view of a gripping claw unit of the gripping device. [Figure 9] FIG. 2 is a perspective view of the gripping device with the gripping jaw units in a closed state. [Figure 10] FIG. 2 is a front view of the gripping device with the gripping jaw units in a closed state. [Figure 11] FIG. 10 is a perspective view of a gripping device according to a second embodiment of the present invention. [Figure 12] FIG. [Figure 13] FIG. 2 is a perspective view of a gripping claw unit of the gripping device. [Figure 14] FIG. 2 is a front view of the gripping device with the gripping jaw units in a closed state. [Figure 15] FIG. 10 is a perspective view of a gripping device according to a third embodiment of the present invention. [Figure 16] FIG. 2 is a perspective view of a gripping claw unit of the gripping device. [Figure 17] FIG. 10 is a perspective view of a gripping device according to a fourth embodiment of the present invention. [Figure 18] FIG. 2 is a perspective view of a gripping claw unit of the gripping device. [Figure 19] FIG. 4 is a cross-sectional view of a main part of the gripping jaw unit. [Figure 20] FIG. 2 is a perspective view of the gripping device with the gripping jaw units in a closed state. [Figure 21] FIG. 10 is a perspective view of a gripping device according to a fifth embodiment of the present invention. [Figure 22] FIG. 2 is a perspective view of a gripping claw unit of the gripping device. [Figure 23] FIG. 4 is a cross-sectional view of a main part of the gripping jaw unit. [Figure 24] FIG. 10 is a cross-sectional view of a main part showing a first modified example in which the gripping jaw unit is partially modified. [Figure 25] FIG. 10 is a cross-sectional view of a main part of the first modified example of the gripping jaw unit in a closed state. [Figure 26] FIG. 10 is a cross-sectional view of a main part showing a second modified example of the gripping jaw unit. [Figure 27] FIG. 10 is a cross-sectional view of a main part of the second modified example of the gripping jaw unit in a closed state. [Figure 28] FIG. 10 is a perspective view of a gripping device according to a sixth embodiment of the present invention. [Figure 29] 10 is a front view of the gripping device with the gripping jaw units of the gripping device in a closed state. FIG. [Figure 30] FIG. [Figure 31] FIG. 10 is a conceptual diagram showing a gripping device according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0023] [First embodiment] A gripping device according to an embodiment of the present invention will be described with reference to Figures 1 to 10. As shown in Figure 1, the gripping device 1 is connected to the tip of a work machine 2 such as a robot. The gripping device 1 grips and releases a workpiece W. Examples of the workpiece W include, but are not limited to, mechanical parts and electronic parts.
[0024] 2A, the gripping device 1 includes a gripping jaw unit (described later) 3 that operates in an opening / closing direction C1 to grip and release the workpiece W, a gripping mechanism 4, an opening / closing drive source 5 shown in FIGS. 3 and 4, a rotation drive source 6, and a connecting part 7 that is a base-end component of the gripping device 1. The connecting part 7 is detachably connected to the tip of an arm of a robot or the like.
[0025] <Gripping mechanism> 1, the gripping mechanism 4 supports the gripping jaw unit 3 including a pair of gripping jaws 8, 8 so as to be operable in the opening / closing direction C1, and rotates around a rotation axis C parallel to the opening / closing direction C1. The gripping mechanism 4 includes an opening / closing mechanism 9 and a rotation mechanism 10. <Opening and closing mechanism> The opening / closing mechanism 9 includes linear motion elements 11, 11 that move the pair of gripping claws 8, 8 in the opening / closing direction C1, and an opening / closing mechanism housing 12. The opening / closing mechanism housing 12 is fixed to the connecting portion 7, and a main body of the opening / closing drive source 5 is connected to the opening / closing mechanism housing 12. The output portion of the opening / closing drive source 5 movably supports linear motion elements 11, 11 that face each other at a predetermined interval.
[0026] <Rotation mechanism> The rotation mechanism 10 supports the gripping jaw unit 3 for rotation about a rotation axis C. The rotation mechanism 10 has a fixed housing part 13, an opening / closing housing part 14, an extension / retraction rotation mechanism 15 shown in FIG. 7, a power transmission mechanism 16 shown in FIG. 2A, and a swing rotation shaft 17. As shown in Fig. 4, the fixed-side housing part 13 is fixed to the connecting part 7 and the opening / closing mechanism housing part 12. As shown in Fig. 2A, the opening / closing-side housing part 14 is fixed to one linear motion element 11 (on the right side in Fig. 2A) of the opening / closing mechanism 9, and is capable of linear movement together with this linear motion element 11 in the opening / closing direction C1.
[0027] <Extendable and rotatable mechanism> The telescopic rotation mechanism 15 is supported by the fixed-side housing 13 and the opening / closing mechanism housing 12, and transmits the rotation of the rotation drive source 6 shown in FIGS. 5 to 7 to the swinging rotation shaft 17 via a power transmission mechanism 16 shown in FIG. 2A, which will be described later. Furthermore, the telescopic rotation mechanism 15 enables the swinging rotation shaft 17 to move in the opening / closing direction C1 together with the opening / closing side housing 14. As shown in FIG. 7, the telescopic rotation mechanism 15 has a reduction mechanism 18, an input shaft 19, an output shaft 20, a sliding bearing 21, a first gear 22, and a second gear 23.
[0028] The reduction mechanism 18 has a spur gear 18a fixed to the output shaft of the rotary drive source 6, and a spur gear 18b that meshes with the spur gear 18a and is fixed to the input shaft 19, and these spur gears 18a, 18b reduce the rotation of the rotary drive source 6. A rolling bearing is provided in the telescopic rotation mechanism main body, and the input shaft 19 is rotatably supported about the rotation axis C2 by the rolling bearing. Therefore, the rotation of the rotary drive source 6 is transmitted to the input shaft 19 by the reduction mechanism 18, and the input shaft 19 is rotatably supported about the rotation axis C2 by the rolling bearing.
[0029] The output shaft 20 is supported for rotation parallel to the input shaft 19. Slide bearings 21, 21 are provided at a predetermined interval on the telescopic rotation mechanism body. The telescopic rotation mechanism 15 supports the output shaft 20 by these slide bearings 21, 21 so that the output shaft 20 can slide freely in the axial direction parallel to the opening / closing direction C1 and also support rotation. A first gear 22 is provided on the input shaft 19, and a second gear 23 is provided on the output shaft 20. The first and second gears 22, 23 are spur gears that mesh with each other.
[0030] The second gear 23 meshes with the first gear 22 to transmit the rotational force of the first gear 22 and is movable in an axial direction parallel to the opening / closing direction C1 relative to the first gear 22. Either the first or second gear 22, 23 has an axial dimension longer than the opening / closing width of the gripping mechanism 4 (FIG. 2A). In this example, the axial dimension L1 of the first gear 22 is set longer than the opening / closing width.
[0031] <Power transmission mechanism> 2A, power transmission mechanism 16 transmits the rotation of output shaft 20 of telescopic rotation mechanism 15 to oscillating rotation shaft 17. Power transmission mechanism 16 includes, for example, input gear 16A, output gear 16B, and gear 16C provided between input and output gears 16A and 16B as a transmission element for offsetting the inter-axial distance. Input gear 16A, gear 16C, and output gear 16B are each a gear train made up of spur gears.
[0032] The input gear 16A, the gear 16C, and the output gear 16B are provided inside the opening / closing side housing 14. The input gear 16A is connected to one longitudinal end of the output shaft 20 of the telescopic rotation mechanism 15. The output gear 16B is rotatably supported by the opening / closing side housing 14 coaxially with the swing rotation shaft 17. The gear 16C, which is the transmission element, meshes with the input gear 16A and the output gear 16B, and is rotatably supported by the opening / closing side housing 14. Therefore, the power transmission mechanism 16 transmits the rotation of the telescopic rotation mechanism 15 to the swing rotation shaft 17 via the input gear 16A, gear 16C, and output gear 16B.
[0033] [Modification of the first embodiment] As a modified example of the power transmission mechanism 16, the power transmission mechanism 16 of the rotation mechanism 10 may be a combination of a pulley and a belt. Specifically, as shown in FIG. 2B , the power transmission mechanism 16 includes primary and secondary pulleys 16a and 16b and a timing belt 16c, and these components 16a, 16b, and 16c are provided inside the opening / closing housing 14. The primary pulley 16a is connected to one longitudinal end of the output shaft 20 of the telescopic rotation mechanism 15. The secondary pulley 16b is rotatably supported by the opening / closing housing 14 coaxially with the swinging rotation shaft 17. The timing belt 16c is wound around the primary pulley 16a and the secondary pulley 16b. Therefore, the power transmission mechanism 16 transmits the rotation of the telescopic rotation mechanism 15 to the swinging rotation shaft 17 via the primary pulley 16a, the timing belt 16c, and the secondary pulley 16b.
[0034] <Oscillating rotation shaft> 2A , one axial end of the swingable rotation shaft 17 is rotatably supported by the open / close side housing 14. The swingable rotation shaft 17 supports one of the grip claws 8 and also rotatably supports the entire grip claw unit 3 so that it can swing about the rotation axis C. The axis of the swingable rotation shaft 17 is concentric with the rotation axis C. A grip claw attaching / detaching member 24 that detachably supports one of the grip claws 8 of the grip claw unit 3 is provided at the other axial end of the swingable rotation shaft 17. Note that in the first embodiment, the grip claw attaching / detaching member 24 detachably supports one of the grip claws 8 of the grip claw unit 3, but since both of the grip claws 8, 8 are detachable, the grip claw unit 3 itself may be detachable.
[0035] <Opening and closing drive source> As shown in FIG. 1 , the opening / closing drive source 5 is a drive source that drives the gripping jaw unit 3 to open and close. For example, a parallel chuck including an air cylinder driven by compressed air is used as the opening / closing drive source 5. Linear motion elements 11 are connected to a pair of chuck portions 5a, which are the output portions of this parallel chuck. The opening / closing drive source 5 drives the pair of gripping jaws 8,8 to open and close in cooperation with the linear motion elements 11 and the swing rotation shaft 17.
[0036] <Rotation drive source> 2A is a drive source that drives the gripping jaw unit 3 to rotate around the rotation axis C. The rotation drive source 6 is, for example, an electric motor, and this motor is supported by the fixed housing part 13.
[0037] <About the gripping jaw unit, etc.> 8, the gripping claw unit 3 has a pair of gripping claws 8, 8 that move in the opening / closing direction C1, and a gripping claw connecting mechanism 25 that connects parts of these gripping claws 8, 8. The gripping claw connecting mechanism 25 is formed in a substantially U-shape and has a restoring force that allows one of the gripping claws 8 to elastically deform relative to the other gripping claw 8. The gripping claw unit 3 is a metal or resin part in which the pair of gripping claws 8, 8 and the gripping claw connecting mechanism 25 are integrally provided.
[0038] The term "integrally provided" means that the gripping claws 8, 8 and the gripping claw connecting mechanism 25 are not formed by combining a plurality of elements but are formed as a part or the whole of a single object from a single material by, for example, forging, machining, etc. As a pair of gripping claws 8, 8 having the gripping claw connecting mechanism 25 with the restoring force, for example, general tweezers or the like can be used.
[0039] 2A, a pressing member 26 that contacts and moves away from the other gripping claw 8 is provided on the linear motion elements 11, 11 at a portion facing the other gripping claw 8. The gripping claw 8 supported by the gripping claw attachment / detachment member 24 is referred to as one gripping claw 8, and the gripping claw 8 that is not supported by the gripping claw attachment / detachment member 24 is referred to as the "other gripping claw 8." The pressing member 26 has a housing 26a and a contact ball 26b rotatably supported by the housing 26a. The housing 26a is provided at the tip of the linear motion element 11 in the extension direction.
[0040] 9 and 10 , by moving the linear moving elements 11, 11 in one opening / closing direction C1 by the opening / closing drive source 5, the contact ball 26b of the press-down member 26 abuts against the other gripping claw 8 against the restoring force, bringing the pair of gripping claws 8, 8 into a closed state. As shown in FIGS. 1 and 2A , by moving the linear moving elements 11, 11 in the other opening / closing direction C1 by the opening / closing drive source 5, the contact ball 26b is separated from the other gripping claw 8, and the pair of gripping claws 8, 8 are brought into an open state by the restoring force. In this way, the opening / closing drive source 5 can drive the linear moving elements 11, 11 and the swing rotation shaft 17 to cooperate with each other to open and close the pair of gripping claws 8, 8.
[0041] <Action and effect> With the gripping device 1 described above, the gripping jaw unit 3 can be oscillated and rotated while the workpiece W is gripped by the pair of gripping jaws 8, 8 shown in FIG. 2A. Therefore, the workpiece W can be oscillated and rotated without operating the work machine to which the gripping device 1 is connected. Because the objects of rotation are mainly the workpiece W and the gripping jaws 8, 8, the weight and moment of inertia of the objects of rotation are reduced. As a result, high-speed rotation of the work machine is possible.
[0042] The swing rotation shaft 17 supports one of the gripping claws 8 and also rotatably supports the entire gripping claw unit 3, and the gripping claw unit 3 is rotationally driven by the rotation drive source 6. The pair of gripping claws 8, 8 are driven to open and close by the opening / closing drive source 5 (FIG. 1) through cooperation between the linear motion elements 11, 11 and the swing rotation shaft 17. That is, by moving the linear motion elements 11, 11 in one opening / closing direction C1 by the opening / closing drive source 5 (FIG. 1), the press-down member 26 comes into contact with the other gripping claw 8 against the restoring force, bringing the pair of gripping claws 8, 8 into a closed state. By moving the linear motion elements 11, 11 in the other opening / closing direction C1 by the opening / closing drive source 5, the pair of gripping claws 8, 8 are brought into an open state by the restoring force.
[0043] In this way, the pair of gripping jaws 8, 8 are driven to open and close by the opening / closing drive source 5 (Fig. 1) through the cooperation of the linear motion elements 11, 11 and the swing rotation shaft 17. Therefore, unlike the conventional structure described above, there is no need to provide a mechanism for distributing rotational power from one drive source to both gripping jaws, or a drive source for simultaneously rotating independent mechanisms, and the entire gripping device can be made simpler than the conventional structure. Therefore, the gripping device 1 can be made lighter and more compact than the conventional structure.
[0044] For example, ordinary tweezers can be retrofitted as a pair of gripping jaws 8, 8 having the gripping jaw connecting mechanism 25 with the restoring force. This allows the approach angle to the workpiece W, for example, during bulk picking, to be changed using only the tip of the gripping device 1, making it possible to avoid interference between the robot and the gripping device 1 in an extremely small space. Furthermore, when tweezers are retrofitted, the manufacturing costs of the gripping device 1 can be reduced compared to designing a new dedicated gripping jaw unit 3.
[0045] The gripping mechanism 4 includes a rotation mechanism 10 that supports the gripping jaw unit 3 to rotate about the rotation axis C, and this rotation mechanism 10 transmits the rotation of the rotation drive source 6 to the swinging rotation shaft 17 and has an extension / retraction rotation mechanism 15 that enables the swinging rotation shaft 17 to extend and retract in the opening / closing direction C1. This makes it possible to transmit rotation while the gripping jaw unit 3 extends and retracts in the opening / closing direction C1, to transmit rotation while stopped at two points before and after the extension / retraction movement, and to transmit rotation at any point during the extension / retraction movement. Since the rotation drive source 6 is a motor, the posture of the workpiece W can be easily changed to any inclination.
[0046] The swing rotation shaft 17 is provided with a gripping jaw attaching / detaching member 24 that detachably supports one of the gripping jaws 8 of the gripping jaw unit 3. This allows the gripping jaw unit 3 to be easily replaced depending on the shape of the workpiece W, the conditions of use of the gripping device 1, etc.
[0047] 7, the telescopic rotation mechanism 15 has a reduction gear mechanism 18, an input shaft 19, an output shaft 20, a sliding bearing 21, a first gear 22, and a second gear 23. The second gear 23 meshes with the first gear 22 to transmit the rotational force of the first gear 22 and is movable relative to the first gear 22 in an axial direction parallel to the opening / closing direction C1. Either the first or second gear 22, 23 has an axial dimension L1 longer than the opening / closing width of the gripping mechanism 4 (FIG. 2A). Therefore, with a small number of parts, it is possible to reliably transmit rotational torque from the input shaft 19 to the output shaft 20 and to move the output shaft 20 in the telescopic direction, which is the axial direction.
[0048] The telescopic rotation mechanism 15 has the sliding bearings 21, 21 that support the output shaft 20 so that it can slide freely in the axial direction, and therefore has a simple structure that can maintain the rotation of the output shaft 20 and allow the output shaft 20 to slide in the axial direction. Furthermore, the output shaft 20 is less likely to wear out than in a structure that does not have a sliding bearing, and the durability of the telescopic rotation mechanism 15 can be improved. Because the first and second gears 22 and 23 are spur gears, the rotation speed of the telescopic rotation mechanism 15 and the distance between the input and output shafts 19 and 20 can be adjusted by changing the diameter and number of teeth of the spur gears. This increases the degree of freedom in the capacity, arrangement, etc. of the rotation drive source 6.
[0049] As shown in Figure 2A, the gripping mechanism 4 has a detachable connecting part 7 at the tip of the work machine 2. This makes it easy to replace the opening / closing mechanism 9 with one that has a different opening / closing stroke, for example, depending on the application of the work machine 2, the shape of the workpiece W, etc., thereby reducing the amount of work required.
[0050] <Other embodiments> In the following description, parts corresponding to matters previously described in each embodiment are given the same reference numerals, and duplicated description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those in the previously described embodiment unless otherwise specified. The same configuration produces the same effects. It is possible to combine not only the parts specifically described in each embodiment, but also partially combine embodiments as long as there is no particular problem with the combination.
[0051] [Second embodiment: Figs. 11 to 14] <Grip jaw unit hinge structure 1> 11 and 12, the gripping claw unit 3A has a pair of gripping claws 8, 8, a hinged gripping claw connecting mechanism 25, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in Fig. 12, one gripping claw 8 is rotatably supported on the swinging rotation shaft 17, and the other gripping claw 8 is connected to the linear motion element 11 via the passive rotation shaft 27. The passive rotation shaft 27 and the swinging rotation shaft 17 are arranged coaxially.
[0052] As shown in Figure 13, each gripping jaw 8 has a jaw 8a and a jaw holder 8b that detachably holds the jaw 8a with a screw 28 or the like. The jaw 8a can be easily replaced with respect to the jaw holder 8b depending on the shape of the workpiece, the conditions of use of the gripping device, etc. In this way, the shape of the tip of the gripping jaw can be easily changed.
[0053] The hinged gripping claw coupling mechanism 25, swinging rotation shaft 17, and passive rotation shaft 27 in Figure 12 allow the pair of gripping claws 8, 8 to move parallel to each other but not twist, as shown in Figure 14. When one gripping claw 8 is rotated around the swinging rotation shaft 17, the other gripping claw 8 rotates around the passive rotation shaft 27 in sync with the first gripping claw 8. In order to move the pair of gripping claws 8, 8 parallel to each other, the hinged gripping claw coupling mechanism 25 requires three sections, as shown in Figure 13. Furthermore, the gripping claw coupling mechanism 25 is located within the plane in which the gripping claws 8, 8 are to be held.
[0054] 14, the pair of gripping claws 8, 8 are each rotatably supported by the gripping mechanism 4, which increases the rigidity of the gripping claw unit 3A and prevents undesired tilting of the gripping claws 8, 8, misalignment of the open / closed positions, etc. This makes it possible to further improve the positioning accuracy of the gripping device 1. Other advantageous effects are similar to those of the above-described embodiment.
[0055] [Third embodiment: Figs. 15-16] <Grip jaw unit hinge structure 2> 15, the gripping claw unit 3B may have a pair of gripping claws 8, 8, a hinge-like gripping claw connecting mechanism 25, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in Fig. 16, the gripping claw connecting mechanism 25 has hinge bodies 25a, 25a and rotation shafts 25b, 25b, 25c.
[0056] The claw holder 8b of each gripping claw 8 is provided with a rotation shaft 25b that is a rotation support shaft for the hinge body 25a. The base end of each hinge body 25a is rotatably supported by the claw holder 8b via the rotation shaft 25b, and the tip end of each hinge body 25a is rotatably supported relative to each other via the rotation shaft 25c. The rotation shafts 25b, 25b, and 25c are parallel to the plane PL on which the gripping claws 8 are to be held and to the longitudinal direction C3 of the claw holder 8b. Furthermore, each hinge body 25a is arranged on a plane inclined relative to the plane PL.
[0057] With the gripping claw unit 3B equipped with the gripping claw connecting mechanism 25, when the gripping claws 8, 8 are opened or closed, most of the hinge bodies 25a, 25a extend outward beyond the claw holder 8b, etc., making them less likely to interfere with the claws 8a and gripping mechanism 4 in FIG. 15. With the gripping claw unit 3B equipped with such a hinge structure, the gripping claw connecting mechanism 25 can be easily arranged even if the opening and closing width of the gripping mechanism 4 is small. Furthermore, because the pair of gripping claws 8, 8 are each rotatably supported by the gripping mechanism 4, it is possible to increase the rigidity of the gripping claw unit 3B and further improve the positioning accuracy of the gripping device 1. Other advantageous effects similar to those of the first embodiment are achieved.
[0058] [Fourth embodiment: Figs. 17 to 20] <Grip jaw slide structure 1> As shown in Fig. 17, the gripping claw unit 3C has a pair of gripping claws 8, 8, a gripping claw coupling mechanism 25A that connects the gripping claws 8, 8 so that they can slide in the opening / closing direction C1, and a passive rotation shaft 27 that rotatably supports the other gripping claw 8 on the gripping mechanism 4. As shown in Fig. 18, the gripping claw coupling mechanism 25A has multiple (two in this example) rod-shaped members 29 that extend parallel to the opening / closing direction C1. These rod-shaped members 29, 29 are arranged in parallel at a predetermined interval. As shown in Fig. 19, the rod-shaped members 29, 29 are, for example, common parts and have the shape of a round shaft with a circular cross section.
[0059] A retaining member 30 such as a retaining ring is provided at each longitudinal end of each rod-shaped member 29 to prevent the gripping claws 8 from falling off. A sliding bearing 31 is fitted and fixed into the hole of each gripping claw 8 through which the rod-shaped member 29 is inserted to improve the sliding of the gripping claws 8. 17 and 20, the gripping claw unit 3C opens and closes in accordance with the opening and closing of the opening / closing mechanism 9. This gripping claw unit 3C can also omit the passive rotation shaft 27. When the passive rotation shaft 27 is omitted, a restoring element such as a compression coil spring is provided to open the gripping claw unit 3C when the opening / closing mechanism 9 is opened. When the gripping claw unit 3C is provided with the restoring element, one of the linear motion elements 11 (on the left side in FIG. 17) only needs to press down on the other gripping claw 8, as with the gripping claw unit 3 of the first embodiment (FIG. 1).
[0060] According to this gripping jaw unit 3C, two rod-shaped members 29, 29 are inserted through a pair of gripping jaws 8, 8, so twisting between the gripping jaws 8, 8 can be suppressed. This makes it possible to further improve the positioning accuracy of the gripping device 1. Other effects similar to those of the first embodiment are achieved.
[0061] [Fifth embodiment: Figs. 21 to 23] <Grip Claw Slide Structure 2> As shown in Fig. 21, the gripping claw unit 3D has a pair of gripping claws 8,8 and a gripping claw connection mechanism 25B that connects the gripping claws 8,8 so that they can slide in the opening / closing direction C1. As shown in Fig. 22, the gripping claw connection mechanism 25B connects the pair of gripping claws 8,8 so that they can slide but cannot rotate along the swinging rotation shaft 17. The swinging rotation shaft 17 in this example supports both gripping claws 8,8.
[0062] In this embodiment, as shown in Figure 23, a portion of the outer circumferential surface of the swinging rotation shaft 17 in the longitudinal direction along which the gripping claws 8, 8 slide is made into a polyhedron (in this example, an octahedron) 17a, or a key 32 is provided on the portion in the longitudinal direction. As a result, the gripping claws 8, 8 cannot rotate relative to the swinging rotation shaft 17. According to this embodiment, the gripping claw unit 3D (Figure 21) itself can be made more compact than in the fourth embodiment. This makes it possible to more reliably avoid interference with gripping devices in an extremely small space. Other effects similar to those of the first embodiment are achieved.
[0063] [Modification of the fifth embodiment] <Modified rotation stopper: Figures 24-25> In the embodiment shown in FIG. 24 , a secondary pulley 16b and one of the gripping claws 8 are fixed to one end of the oscillating rotation shaft 17 and rotatably connected to one of the linear motion elements 11. A bearing may be provided at this connection as a rotational resistance reduction member 31A. The other gripping claw 8A is connected to the oscillating rotation shaft 17 so as to be movable in the axial direction but not rotatable. A ball guide, linear guide, slider, or the like may be provided at this connection as a sliding resistance reduction member 31AA. The other end of the oscillating rotation shaft 17 is connected to the other linear motion element 11A so as to be movable in the axial direction and rotatable. A sliding bearing or ball bush may be provided at this connection as a member 31 for reducing rotational and sliding resistance. This modification provides substantially the same effects as the fifth embodiment. Furthermore, the gripping claw slide structure can operate more smoothly than in the fifth embodiment, resulting in higher precision and less backlash in the gripping claw unit. This increases the rigidity of the gripping claw unit and extends its lifespan. In this way, the gripping jaw unit can be made highly accurate, highly rigid, and have a long life.
[0064] [Modification of the fifth embodiment] <Cantilever spring structure: Figures 26 to 27> As shown in Figure 26, one gripping claw 8 is integrally provided at the longitudinal middle portion of the oscillating rotation shaft 17, and as shown in Figure 27, the other gripping claw 8 is connected to the oscillating rotation shaft 17 so as to be slidable but non-rotatable. Furthermore, as shown in Figure 26, a restoring element 33 such as a compression coil spring is provided between the pair of gripping claws 8, 8 on the outer periphery of the oscillating rotation shaft 17. The oscillating rotation shaft 17 is rotatably supported by a cantilever on one linear motion element 11 (on the right side in Figure 26). This cantilever spring structure has higher rigidity than the aforementioned rotation stopper modification and the first embodiment, and can reduce the number of parts such as the pressing member, making it possible to make the device more compact. In addition, it has almost the same effects as the fifth embodiment.
[0065] [Sixth embodiment: Figs. 28 to 30] <Link mechanism> As shown in Figures 28 and 29, the gripping claw unit 3E has a pair of gripping claws 8,8 and a gripping claw linking mechanism 25C consisting of a link mechanism 34 that links the gripping claws 8,8. As shown in Figure 30, the link mechanism 34 restricts the pair of gripping claws 8,8 so that they move while remaining parallel on a plane. With the gripping claw unit 3E equipped with the gripping claw linking mechanism 25C, when the gripping claws 8,8 are opened or closed, most of the link mechanism 34 is positioned to the side of the claw holder 8b, etc., so the gripping claw linking mechanism 25C can be easily positioned even if the opening and closing width of the gripping mechanism is small. Other operational effects similar to those of the third embodiment are achieved.
[0066] [Seventh embodiment: Figure 31] <Direct mounting structure of rotational drive source and linear motion element> As shown in Figure 31, the rotational drive source 6 may be directly attached to one of the linear motion elements 11, 11. In this case, the rotational axis of the rotational drive source 6 is coaxially connected to the oscillating rotational axis 17, or the rotational axis also serves as the oscillating rotational axis 17. Therefore, it is possible to rotate the gripping jaw unit 3 directly via the rotational axis of the rotational drive source 6. With this gripping device, it is possible to omit the power transmission mechanism 16 (Figure 2A) and the like, thereby achieving even lighter weight and more compactness than conventional structures.
[0067] The opening / closing drive source 5 is not limited to the air cylinder, but may be, for example, an electric cylinder, an electric motor, or a hydraulic cylinder such as a hydraulic cylinder. The rotation drive source 6 may be a structure utilizing air pressure such as an air cylinder, or a structure utilizing hydraulic pressure such as a hydraulic actuator. The power transmission mechanism 16 in FIG. 2A may have a structure including drive and driven sprockets and a drive chain looped around these sprockets. The pair of gripping claws 8, 8 (8A) can be placed in a closed state by moving the tips of the pair of gripping claws 8, 8 (8A) away from each other, and the pair of gripping claws 8, 8 (8A) can be placed in an open state by moving the tips of the pair of gripping claws 8, 8 close to each other.
[0068] A constant velocity joint (not shown) may be used as the transmission element of the telescopic rotation mechanism 15. Specifically, as a constant velocity joint, one transmission element is a cylindrical member having a plurality of guide grooves, and the other transmission element is a shaft-shaped member, with rolling elements circumferentially evenly spaced between the cylindrical member and the shaft-shaped member. The constant velocity joint further includes a cage that prevents the rolling elements from falling off or colliding with each other.
[0069] The gripping device 1 can be attached to an output unit such as a linear actuator. The gripping device 1 can also be installed on a fixed object such as a frame and used in combination with other work machines.
[0070] Although the embodiments of the present invention have been described above, the disclosed embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]
[0071] 1...gripping device, 2...work machine, 3...gripping claw unit, 4...gripping mechanism, 5...opening / closing drive source, 6...rotation drive source, 7...connection portion, 8, 8A...gripping claw, 9...opening / closing mechanism, 10...rotation mechanism, 11, 11A...linear motion element, 12...opening / closing mechanism housing portion, 13...fixed side housing portion, 14...opening / closing side housing portion, 15...telescopic rotation mechanism, 16...power transmission mechanism, 17...oscillating rotation shaft, 18...reduction mechanism, 18a, 18b...spur gear, 19...input shaft, 20...output shaft, 21...sliding bearing, 22...first gear, 23...second gear, 24...gripping claw attachment / detachment member, 25-25C...gripping claw coupling mechanism, 26...pressing member, 27...passive rotation shaft, W...work
Claims
1. a gripping jaw unit that operates in an opening and closing direction to grip and release a workpiece; a gripping mechanism that supports the gripping jaw unit so as to be movable in the opening and closing direction and rotates around a rotation axis that is parallel to the opening and closing direction; an opening / closing drive source that drives the gripping jaw unit to open and close; a rotation drive source that rotates the gripping jaw unit around the rotation axis, The gripping claw unit has a pair of gripping claws and a gripping claw connecting mechanism that connects a part of the gripping claws, The gripping mechanism includes: a swing rotation shaft that supports one or both of the gripping jaws and rotatably supports the entire gripping jaw unit so that the gripping jaw unit can swing about the rotation axis; an opening / closing mechanism including a linear motion element that moves the pair of gripping claws in the opening / closing direction, The gripping device drives the pair of gripping jaws to open and close by the opening and closing drive source in cooperation with the linear motion element and the swing rotation shaft.
2. 2. The gripping device according to claim 1, wherein the gripping mechanism includes a rotation mechanism that supports the gripping claw unit for rotation around the rotation axis, and the rotation mechanism transmits the rotation of the rotation drive source to the oscillating rotation shaft and has an extension and retraction rotation mechanism that enables the oscillating rotation shaft to move in the opening and closing direction.
3. 3. The gripping device according to claim 1, wherein the rotation drive source is a motor.
4. 3. The gripping device according to claim 1, wherein the swing rotation shaft is provided with a gripping claw attaching / detaching member for detachably supporting one of the gripping claws of the gripping claw unit.
5. 5. The gripping device according to claim 4, wherein the gripping claw coupling mechanism has a restoring force that allows one of the gripping claws to be elastically deformed relative to the other gripping claw, a pressing member that abuts against and separates from the other gripping claw is provided at a portion of the linear motion element that faces the other gripping claw; The linear motion element is moved in one of the opening and closing directions by the opening and closing drive source, thereby causing the pressing member to abut against the other gripping claw against the restoring force, thereby bringing the pair of gripping claws into a closed state; The gripping device causes the opening / closing drive source to move the linear motion element in the other opening / closing direction, thereby opening the pair of gripping claws by the restoring force.
6. 3. The gripping device according to claim 1, wherein the gripping jaw unit has a passive rotation shaft that rotatably supports the other gripping jaw on the gripping mechanism.
7. 3. The gripping device according to claim 2, wherein the telescopic rotation mechanism comprises: an input shaft to which rotation of the rotation drive source is transmitted and which is rotatably supported about the rotation axis; an output shaft that is rotatably supported parallel to the input shaft; a first gear provided on the input shaft; a second gear that is provided on the output shaft and meshes with the first gear to transmit a rotational force of the first gear, and that is movable in an axial direction parallel to the opening and closing direction relative to the first gear, A gripping device in which one of the first and second gears has an axial dimension longer than the opening / closing width of the gripping mechanism.
8. 8. The gripping device according to claim 7, wherein the telescopic rotation mechanism has a sliding bearing that supports the output shaft so that the output shaft can slide in the axial direction.
9. 8. The gripping device according to claim 7, wherein the transmission elements of the rotation mechanism are pulleys and a belt.
10. 8. The gripping device according to claim 7, wherein the transmission element of the rotation mechanism is a spur gear.
11. 3. A gripping device according to claim 1, wherein the gripping mechanism has a detachable connecting portion attached to a tip of a working machine.
Citation Information
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