JP2022162318A - Holding device and robot arm - Google Patents

Abstract

To provide a holding device capable of holding an object to be held securely regardless of positioning accuracy.SOLUTION: A holding device 20 includes: a first holding part 21 which may move relative to workpiece W which is an object to be held; a second holding part 22 which may move in an opposite direction of the first holding part 21 and hold the workpiece W with the first holding part 21; a first slide part 211 and a second slide part 221 which are provided at a contact portion, which contacts with the workpiece W, of at least one of the first holding part 21 and the second holding part 22 and extend in a direction intersecting with a moving direction of the first holding part 21 and the second holding part 22 at a non-right angle; and a first flange part 213 and a second flange part 223 where the workpiece W sliding to sliding ends of the first slide part 211 and the second slide part 221 contacts to stop.SELECTED DRAWING: Figure 6

Description

The present invention relates to a gripping device that grips an object to be gripped, and a robot arm equipped with the gripping device.

2. Description of the Related Art At industrial sites such as factories, distribution warehouses, construction sites, and hospitals, industrial robots have been introduced to perform various tasks in place of humans. Many conventional industrial robots are large and have high output, and for safety reasons, it was necessary to set up an isolated space where humans could not enter and let them work. On the other hand, in recent years, the introduction of collaborative robots that work together with humans in the same space is progressing. Collaborative robots are smaller than conventional industrial robots, and can be installed in smaller spaces.

JP 2017-26150 A JP 2009-291869 A

Patent Literature 1 discloses a technique for imparting flexibility to joints of a robot arm as a collaborative robot by using a series elastic actuator including curved elastic elements. Even if a person working together in the same space collides with this robot arm, the elastic element inside the joint elastically deforms to absorb the impact, improving safety.

On the other hand, the flexibility given to the joint by the series elastic actuator has a trade-off relationship with the positioning accuracy of the robot hand that performs various tasks at the tip of the robot arm. For this reason, as in the technique disclosed in Patent Document 2, a small locking portion provided on a grasping portion (grasping fingers) as a robot hand and a small locked portion provided on a grasped object (attachment) are used. For applications that require accurate positioning, the series elastic actuator of Patent Document 1, which lowers the positioning accuracy of the gripping portion, cannot be used.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a gripping device capable of reliably gripping a gripping target regardless of positioning accuracy.

In order to solve the above problems, a gripping device according to one aspect of the present invention includes a first gripping section that can move with respect to a gripping target, and a second gripping section that can grip the gripping target between the first gripping section. and a sliding portion provided at a contact portion of at least one of the first gripping portion and the second gripping portion with a gripped object and extending in a direction non-perpendicular to the moving direction of the first gripping portion and intersecting therewith. and a stopping portion with which the grasped object that has slid to the sliding end of the sliding portion contacts and stops.

In this aspect, even if the positioning accuracy of the gripping device with respect to the gripped object is low, the gripping device can start the gripping operation by the first gripping portion and the second gripping portion. The object to be gripped between the first gripping portion and the second gripping portion slides along the sliding portion due to the gripping force, and stops by contacting the stopping portion at the sliding end. In this way, the gripping target is finally positioned and gripped by the sliding portion and the stop portion, so the gripping target can be securely gripped regardless of the initial positioning accuracy of the gripping device with respect to the gripping target.

Another aspect of the invention is a robotic arm. This robot arm includes a first link, a second link, a joint that connects the first link and the second link so as to allow relative movement, a flexibility imparting part that imparts flexibility to the joint, and the first link or the second link. A gripping device attached to two links, comprising: a first gripping section movable with respect to a gripping target; a second gripping section capable of gripping the gripping target between the first gripping section; a sliding portion provided at a contact portion of at least one of the gripping objects of the second gripping portion and extending in a direction non-perpendicular to the moving direction of the first gripping portion and intersecting with the moving direction of the first gripping portion; a gripping device including a stopping portion with which a gripped object that has slid to the end contacts and stops.

Any combination of the above constituent elements, and any conversion of expressions of the present invention into methods, devices, systems, recording media, computer programs, etc. are also effective as embodiments of the present invention.

According to the present invention, it is possible to provide a gripping device and a robot arm that can reliably grip a gripping target regardless of positioning accuracy.

It is a perspective view showing the appearance of a robot arm. 2 shows an example of use of a robot arm with a gripping device attached. 4 schematically shows the configuration of a coupling device that configures each joint of a robot arm. 4 schematically shows the configuration of a coupling device that configures each joint of a robot arm. 4 shows an example of manufacturing a work as a gripping target. 1 shows a first configuration example of a gripping device. A second configuration example of the gripping device is shown. 3 shows a third configuration example of the gripping device.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. The scales and shapes of the illustrated parts are set for convenience in order to facilitate explanation, and should not be construed as limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the invention in any way. Not all features or combinations thereof described in the embodiments are essential to the invention.

FIG. 1 is a perspective view showing the appearance of a robot arm 100 as an example of an industrial robot or collaborative robot. This robot arm 100 is a vertically articulated robot arm with a serial link mechanism. A robot to which the present invention can be applied is not limited to a robot arm, and may be any robot having joints (corresponding to joints in the human body) connecting a plurality of links (corresponding to bones in the human body) so as to allow relative movement. A parallel link mechanism may be used instead of the serial link mechanism, and a horizontal articulated type may be used instead of the vertical articulated type.

The robot arm 100 has seven joints, a first joint 11, a second joint 12, a third joint 13, a fourth joint 14, a fifth joint 15, a sixth joint 16, and a seventh joint 17, in order from the base 10. has an axis. Each joint corresponds to each joint of the human body. The first joint 11 is the waist, the second joint 12 is the shoulder, the third joint 13 is the upper arm (twisting), the fourth joint 14 is the elbow, and the fifth joint 15 is the forearm (twisting). ), the sixth joint 16 corresponds to the wrist, and the seventh joint 17 corresponds to the fingertip (twist). The direction of each axis can be appropriately designed according to the purpose and application of the robot arm 100, but in this embodiment, assuming that the pedestal 10 is placed on a horizontal plane, the first joint 11 is positioned vertically (with respect to the pedestal 10, which is a horizontal plane). vertical), the second joint 12 is horizontal (parallel to the pedestal 10 which is a horizontal plane), the third joint 13 is vertical to the second joint 12, the fourth joint 14 is horizontal, the fifth joint 15 is oriented vertically with respect to the fourth joint 14 , the sixth joint 16 is oriented horizontally, and the seventh joint 17 is oriented vertically with respect to the sixth joint 16 .

A seventh joint 17 at the tip of the robot arm 100 is attached with an end effector or a robot hand having a shape and function according to the purpose of work. For example, a grapple shape for grabbing things, a shovel shape for scooping things up, a fork shape for supporting and transporting things from below, a hook shape for hooking and transporting things, and a shape for lifting and transporting things. A variety of end effectors are available, such as crane-like. In this embodiment, an example of using a gripping device or a gripper capable of gripping a gripping target with a plurality of gripping portions will be described as an end effector.

FIG. 2 shows an example of use of a robot arm 100 with a gripping device 20 attached as an end effector. An object to be gripped by the gripping device 20 is a casting cast by a metal mold casting method such as a die casting method, and is generically referred to as a work W in this embodiment. The gripping device 20 is moved by the joints 11 to 17 of the robot arm 100 and picks up the work W conveyed from the upstream first conveyor C1. The work W picked up by the gripping device 20 is moved by the joints 11 to 17 of the robot arm 100 and is polished by being pressed against a rotating brush B as a polishing member. The workpiece W after polishing is moved by the joints 11 to 17 of the robot arm 100 and placed on the downstream second conveyor C2.

3 and 4 schematically show the configuration of the connecting device 30 that constitutes the joints 11 to 17 of the robot arm 100. FIG. The coupling device 30 of FIG. 3 can be applied to joints performing a "bending" action such as the second joint 12, the fourth joint 14, and the sixth joint 16 in FIG. 1 can be applied to joints that perform a "twisting" operation, such as the first joint 11, the third joint 13, the fifth joint 15, and the seventh joint 17 in 1.

In FIG. 3, the connecting device 30 connects a first link 41 as a first member and a second link 42 as a second member so as to be capable of relative movement. The connecting device 30 corresponds to a joint in the human body, and the first link 41 and the second link 42 mutually connected by the connecting device 30 correspond to bones in the human body.

The first link 41 and the second link 42 move relative to each other in various manners according to the manner of connection by the connecting device 30 . In the present embodiment, an example in which the first link 41 and the second link 42 rotate relative to each other around a rotation axis A perpendicular to the extending direction of the first link 41 and the second link 42 will be described.

The relative motion between the first link 41 and the second link 42 is not limited to rotational motion, and may be translational motion. For example, the first link 41 and the second link 42 may be configured to relatively translate in the direction perpendicular to the extending direction of the first link 41 and the second link (the direction perpendicular to the paper surface of FIG. 3). Alternatively, the first link 41 and the second link 42 may be configured to relatively translate in a direction parallel to the extending direction of the first link 41 and the second link (the vertical direction in FIG. 3).

The coupling device 30 includes a housing 31 , a control board 32 , a motor 33 , a speed reducer 34 , an elastic member 35 and an output flange 36 . The housing 31 has a shape that is rotationally symmetrical about the rotation axis A, and accommodates the components 32 to 36 of the coupling device 30 therein. A first attachment portion 311 to which the first link 41 is attached and a second attachment portion 312 to which the second link 42 is attached are provided on the outer periphery of the housing 31 .

The first link 41 fixed to the housing 31 at the first attachment portion 311 is rotatable relative to the second link 42 around the rotation axis A integrally with the housing 31 . The second attachment portion 312 is an opening on the bottom side (left side in FIG. 3) that communicates with the internal space of the housing 31 that accommodates the components 32 to 36 . The second link 42 is attached to the connecting device 30 via the output flange 36 provided in this opening.

The control board 32 controls the coupling device 30 under the control of a central controller (not shown) responsible for controlling the robot arm 100 as a whole. For example, the control board 32 performs generation of a drive command for the motor 33, adaptive control based on measurement data of an output shaft encoder (not shown), detection of torque based on elastic deformation of the elastic member 35, adaptive control based on the detected torque, and the like. is done in The motor 33 is an actuator that generates power to rotationally drive the second link 42 around the rotation axis A according to a drive command from the control board 32 . The speed reducer 34 reduces the rotational speed of the motor 33 by gears or the like and generates torque proportional to the speed reduction ratio.

The elastic member 35 is provided in series between the motor 33 and the speed reducer 34 as a power source and the second link 42 as a load that is rotationally driven by the power. Actuator). Even if a human working together with the robot arm 100 as a collaborative robot collides, the elastic deformation of the elastic member 35 absorbs the impact, thereby improving safety. In addition, since the elastic member 35 can store and release the power generated by the motor 33 and the speed reducer 34 and the external force applied to the second link 42 as elastic energy, it can operate efficiently like a human muscle. In particular, when the work W is pressed against another member such as the brush B as shown in FIG. The work W can be efficiently pressed against the brush B by force.

The elastic member 35 is a member that imparts elasticity to the connecting device 30, and is formed of any elastic body such as a spring or rubber, for example. Further, in addition to or instead of the elastic member 35, a resistance imparting member that imparts resistance to the relative rotation of the first link 41 and the second link 42 of the coupling device 30 may be provided. Examples of the resistance imparting member include those that impart resistance by mechanical friction and those that impart resistance by the viscosity of viscous fluid such as oil and grease. The elasticity of the elastic member 35 and the resistance imparted by the resistance imparting member may be made variable by the control board 32 .

The elastic member 35 also functions as a torque sensor that detects torque due to an external force. That is, since the torque caused by the external force causes elastic deformation of the elastic member 35, the torque can be detected based on the amount of elastic deformation. In order to measure the amount of elastic deformation of the elastic member 35, various displacement sensors such as magnetostrictive sensors, strain gauges, piezoelectric elements, polarizing elements, and capacitance sensors may be attached to the surface of the elastic member 35 or the like. The amount of elastic deformation measured by the displacement sensor is converted into torque by an arithmetic device or the like mounted on the control board 32 .

In the above configuration, the speed reducer 34, the elastic member 35, and the resistance imparting member constitute a flexibility imparting portion that imparts flexibility to the coupling device 30 as a joint. Here, flexibility means how easily a joint bends, and it is said that there is flexibility when the joint bends due to an external force. For example, since the speed reducer 34 generates a torque proportional to the speed reduction ratio, by lowering the speed reduction ratio, it is possible to achieve a highly flexible state in which the joint is easily bent by an external force. In addition, the elastic member 35 and the resistance imparting member allow the joint to bend while generating elastic force and resistance against an external force, so it can be said that they impart flexibility to the joint. At least one joint may be provided with the flexibility imparting portion, and all the seven joints 11 to 17 in FIG. 1 may not be provided with the flexibility imparting portion.

An output shaft encoder (not shown) is a rotary encoder that measures the rotational position of the second link 42 relative to the first link 41 about the rotation axis A. The output flange 36 transmits the torque generated by the speed reducer 34 to the second link 42 via the elastic member 35, causing the second link 42 to rotate about the rotation axis A. A bearing 361 is provided around the output flange 36 to facilitate rotation of the second link 42 with respect to the housing 31 .

In the coupling device 30 of FIG. 4, the first link 41 and the second link 42 rotate relative to each other around a rotation axis B parallel to their extending directions. The notch 37 provided on the second link 42 side of the housing 31 prevents the housing 31 from interfering with the rotation of the second link 42 around the rotation axis B by the motor 33 .

Next, the gripping device 20 that is attached to the tip of the robot arm 100 and grips the workpiece W will be described. First, FIG. 5 shows an example of manufacturing a workpiece W as a gripping target. The work W in this example is a casting cast by a die casting method. In the die casting method, a workpiece W having a fixed shape is repeatedly cast by press-fitting a molten metal (molten metal) into a mold. 5A is a plan view of the mold 50, and FIG. 5B is a cross-sectional view of the mold 50. FIG.

The mold 50 includes a movable main mold 50A1 constituting a movable mold and a movable insert 50A2 fitted into the movable main mold 50A1, and a fixed main mold 50B1 constituting a fixed mold and a fixed insert 50B2 fitted into the fixed main mold 50B1. Prepare. The fixed main mold 50B1 is provided with a casting port bush 50C for injecting molten metal into the mold cavity C as the product portion. The movable main mold 50A1 is provided with a flow diverter 50D for directing the molten metal injected from the casting port bushing 50C to the mold cavity C. As shown in FIG. The molten metal from the flow diverter 50D is led into the mold cavity C through runners R, gate runners GR, and gates G provided between the fixed mold and the movable mold. In addition, an overflow gate OG, an overflow OF, and an air vent AV for discharging excess oxides, residues, gases, air, etc. contained in the molten metal filled in the mold cavity C are provided at a plurality of locations around the mold 50. provided in place.

As shown in FIG. 5(A), the workpiece W cast by the above-described mold 50 includes a columnar biscuit BC corresponding to the casting hole bushing 50C and a biscuit BC that expands toward the gate G from the biscuit BC. It includes an extended runner R and a gate runner GR, and a product part molded in a mold cavity C which is the final product. Since many burrs remain on the workpiece W after molding, it is necessary to grip the workpiece W with the gripping device 20 and polish it with the brush B as shown in FIG. Next, a configuration example of the gripping device 20 for gripping the work W will be shown.

FIG. 6 shows a first configuration example of the gripping device 20. As shown in FIG. FIG. 6(A) shows a perspective view of the operation of the gripping device 20 gripping the workpiece W, and FIGS. 6(B) and 6(C) show a top view. The shape of the work W is simplified from that of FIG. 5(A), the biscuit BC is a quadrangular prism, and the gate runner GR extends from the lower end of the biscuit BC without the runner R while expanding. Also, illustration of the gate G and the product portion provided ahead of the gate runner GR is omitted.

The gripping device 20 includes a first gripping portion 21 and a second gripping portion 22 for sandwiching and gripping the gate runner GR of the workpiece W from both sides. The first gripping part 21 and the second gripping part 22 are movable in directions opposite to each other, and when gripping the workpiece W, they move in directions approaching the gate runner GR. That is, as shown in FIG. 6B, the first gripping portion 21 moves rightward so as to approach the gate runner GR from the left side, and the second gripping portion 22 moves rightward so as to approach the gate runner GR from the right side. to the left. One of the first gripping portion 21 and the second gripping portion 22 may be movable, and the other may be fixed.

The first gripping portion 21 is provided at a contact portion with the gate runner GR as a gripping target, and extends in a direction that intersects the moving direction of the first gripping portion 21 and the second gripping portion 22 at a non-perpendicular angle. 1 sliding portion 211 is provided. As shown in FIG. 6B, the first sliding portion 211 extends in a direction that intersects the left-right direction, which is the moving direction of the first gripping portion 21 and the second gripping portion 22, at a non-perpendicular angle. 6(B) before the gripping device 20 grips the workpiece W, the workpiece W is on the first conveyor C1 (FIG. 2) that conveys in the horizontal plane. The first sliding portion 211 of the portion 21 also extends in the horizontal plane.

Further, the extending direction of the first sliding portion 211 substantially coincides with the expanding direction of the gate runner GR, which is the gripped portion to be gripped. For example, the angle formed by the extending direction of the first sliding portion 211 and the expanding direction of the gate runner GR is 5 degrees or less. As a result, the gate runner GR can slide smoothly while being in surface contact with the first sliding portion 211 . Above and below the first sliding portion 211 are provided first guide portions 212H and 212L that guide the gate runner GR while sandwiching the gate runner GR in contact with the first sliding portion 211 from above and below.

The first sliding portion 211 is made of, for example, a self-lubricating material. Examples of self-lubricating materials include polytetrafluoroethylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether, and copolymers of tetrafluoroethylene and hexafluoropropylene. By forming the first sliding portion 211 with a self-lubricating material, the gate runner GR in contact with the first sliding portion 211 can slide smoothly.

The first sliding portion 211 is made of a porous material such as a metal material such as stainless steel, brass, or gunmetal, a ceramic material such as oil stone, or a polymer material such as urethane sponge. A casting agent may be added. Perfluoropolyether and dimethylsilicone are exemplified as lubricants and release agents (hereinafter collectively referred to as lubricants). The lubricant added to the porous material allows the gate runner GR in contact with the first sliding portion 211 to slide smoothly. In addition, unevenness may be formed on the surface of the first sliding portion 211 along the direction in which the gate runner GR slides. It is preferable that the height difference between the protrusions and recesses of the unevenness is 0.1 mm or more. As a result, excessive sliding is suppressed and a stable gripping operation becomes possible.

Similarly to the first gripping portion 21, the second gripping portion 22 is also provided with a second sliding portion 221 and second guide portions 222H and 222L. The first sliding portion 211 and the second sliding portion 221 are non-parallel to each other, and as shown in FIGS. 6B and 6C, spread from the upper biscuit BC toward the lower gate runner GR. do. The expanding direction of the first sliding portion 211 and the second sliding portion 221 substantially coincides with the expanding direction of the gate runner GR, which is the gripped portion to be gripped. For example, the angle formed by the extending direction of the first sliding portion 211 and the expanding direction of the gate runner GR is 5 degrees or less, and the extending direction of the second sliding portion 221 and the expanding direction of the gate runner GR form. The angle is 5 degrees or less. This allows the gate runner GR to slide smoothly while making surface contact with the first sliding portion 211 and the second sliding portion 221 . Although it is preferable to provide sliding portions on both the first gripping portion 21 and the second gripping portion 22 in order to allow the gate runner GR to slide smoothly, only one of the gripping portions 21 and 22 is provided with a sliding portion. may be provided.

As shown in FIG. 6(C), the workpiece W gripped from both sides by the first gripping portion 21 and the second gripping portion 22 moves in the direction in which the first sliding portion 211 and the second sliding portion 221 expand. slide to. That is, the forces applied to the work W from the left and right directions by the first gripping portion 21 and the second gripping portion 22 are changed in direction by the first sliding portion 211 and the second sliding portion 221 intersecting the left and right directions at a non-perpendicular angle. , to move the workpiece W downward in the expanding direction. Due to this force, the workpiece W smoothly slides downward while contacting the first sliding portion 211 and the second sliding portion 221 .

The workpiece W is stopped by contacting the first flange portion 213 and the second flange portion 223 as stopping portions at its sliding ends. As shown in FIG. 6C, the first flange portion 213 is the end portion of the first guide portion 212H at the sliding end (upper end) of the first sliding portion 211, and the second flange portion 223 is the second It is the end of the second guide portion 222</b>H at the sliding end (upper end) of the sliding portion 221 . The columnar biscuit BC of the work W moves downward from FIG. 6B to FIG. 6C. In FIG. W stops sliding. The workpiece W is securely gripped by the first gripping portion 21 and the second gripping portion 22 at this position.

According to the above configuration, even when the positioning accuracy of the gripping device 20 with respect to the workpiece W is low, such as in a collaborative robot having a series elastic actuator, the gripping device 20 has the first gripping part 21 and the second gripping part 21 . A grasping action by the portion 22 can be initiated. Since the workpiece W to be gripped may be placed on the first conveyor C1 with low accuracy, it is possible to configure the equipment for the pre-process of the robot arm 100 at low cost. The workpiece W sandwiched between the first gripping portion 21 and the second gripping portion 22 slides along the first sliding portion 211 and the second sliding portion 221 due to the gripping force. It contacts the flange portion 213 and the second flange portion 223 and stops. In this way, final positioning and gripping of the work W are performed by the sliding portions 211, 221 and the flange portions 213, 223. Therefore, the work W can be securely gripped regardless of the initial positioning accuracy of the gripping device 20 with respect to the work W. can be grasped.

In order to make the most of the advantages peculiar to this embodiment, the gripping device 20 grips the workpiece W by the flexibility imparting parts such as the speed reducer 34, the elastic member 35, and the resistance imparting member provided in each joint. The flexibility of the joint may be increased. By increasing the flexibility of the joint when the gripping device 20 starts gripping the work W as shown in FIG. At least one of the first sliding portion 211 and the second sliding portion 221 is more likely to come into contact with the gate runner GR as the gripped portion. After the gate runner GR once contacts one of the sliding portions 211 and 221, the force between the first gripping portion 21 and the second gripping portion 22 causes the gate runner GR to slide on the sliding portions 211 and 221. , the final positioning and gripping of the workpiece W is automatically performed.

FIG. 7 shows a second configuration example of the gripping device 20. As shown in FIG. 7(A) and 7(B) show the operation of gripping the workpiece W by the gripping device 20 in a side sectional view. 6(B) and 6(C) show the configuration in top view, ie in the horizontal plane, while FIGS. 7(A) and 7(B) show the configuration in side cross-section, ie in the vertical plane. Since most of the constituent elements in FIG. 7 are common to those in FIG. 6, the same reference numerals are given and the explanation will focus on the differences.

The gripping device 20 includes a first gripping portion 21 and a second gripping portion 22 for sandwiching and gripping the work W from both sides. The first gripping part 21 and the second gripping part 22 are movable in directions opposite to each other. That is, as shown in FIG. 7A, the first gripping portion 21 moves rightward so as to approach the work W from the left side, and the second gripping portion 22 moves leftward so as to approach the work W from the right side. move in the direction

The first gripping portion 21 is provided at a contact portion with the workpiece W to be gripped, and extends in a direction non-perpendicular to the moving direction of the first gripping portion 21 and the second gripping portion 22. A sliding portion 211 is provided. As shown in FIG. 7A, the first sliding portion 211 extends in a direction that intersects the left-right direction, which is the moving direction of the first gripping portion 21 and the second gripping portion 22, at a non-perpendicular angle. In the state of FIG. 7A where the gripping device 20 grips the workpiece W, the workpiece W is on the first conveyor C1 (FIG. 2) that conveys in the horizontal plane. The first sliding portion 211 of extends in the vertical plane.

First flange portions 213H and 213L are protruded from the upper and lower ends of the first sliding portion 211 so as to sandwich the workpiece W in contact with the first sliding portion 211 from above and below. The upper first flange portion 213H functions as a stopping portion that stops the work W from sliding, and the lower first flange portion 213L functions as a fall prevention portion that prevents the work W from falling. The first sliding portion 211 is made of, for example, a self-lubricating material. Alternatively, the first sliding portion 211 may be made of a porous material and a lubricant may be added thereto. In addition, unevenness may be formed on the surface of the first sliding portion 211 along the direction in which the workpiece W slides. It is preferable that the height difference between the protrusions and recesses of the unevenness is 0.1 mm or more.

Similarly to the first gripping portion 21, the second gripping portion 22 is also provided with a second sliding portion 221 and second flange portions 223H and 223L. The first sliding portion 211 and the second sliding portion 221 are non-parallel to each other, and expand from bottom to top as shown in FIGS. 7(A) and (B). Although it is preferable to provide sliding portions on both the first gripping portion 21 and the second gripping portion 22 in order to smoothly slide the workpiece W, only one of the gripping portions 21 and 22 is provided with a sliding portion. may

As shown in FIG. 7(B), the workpiece W gripped from both sides by the first gripping portion 21 and the second gripping portion 22 moves in the direction in which the first sliding portion 211 and the second sliding portion 221 expand. slide to. That is, the forces applied to the work W from the left and right directions by the first gripping portion 21 and the second gripping portion 22 are changed in direction by the first sliding portion 211 and the second sliding portion 221 intersecting the left and right directions at a non-perpendicular angle. , to move the workpiece W upward in the expanding direction. Due to this force, the workpiece W smoothly slides upward while contacting the first sliding portion 211 and the second sliding portion 221 .

The workpiece W is stopped by contacting the first flange portion 213H and the second flange portion 223H as stopping portions at its sliding ends. The work W moves upward from FIG. 7(A) to (B). In FIG. 7(B), the work W contacts the first flange portion 213H and the second flange portion 223H, and the work W does not slide. Stop. E1 and E2 represent sliding ends of the sliding portions 211 and 221, respectively. The workpiece W is securely gripped by the first gripping portion 21 and the second gripping portion 22 at this position.

According to the above configuration, final positioning and gripping of the workpiece W is performed by the sliding portions 211, 221 and the flange portions 213H, 223H. The workpiece W can be securely gripped. In order to make the most of the advantages peculiar to this embodiment, the gripping device 20 grips the workpiece W by the flexibility imparting parts such as the speed reducer 34, the elastic member 35, and the resistance imparting member provided in each joint. The flexibility of the joint may be increased.

FIG. 8 shows a third configuration example of the gripping device 20. As shown in FIG. 8A shows a perspective view of the operation of the gripping device 20 gripping the work W, and FIGS. 8B and 8C show a top view. The cylindrical workpiece W is, for example, a biscuit BC shown in FIG. 5(A). Since most of the components in FIG. 8 are common to those in FIG. 6 or 7, the same reference numerals are given and the explanation will focus on the differences.

The gripping device 20 includes a first gripping portion 21 and a second gripping portion 22 for sandwiching and gripping the work W from both sides. The first gripping part 21 and the second gripping part 22 are movable in directions opposite to each other. That is, as shown in FIG. 8B, the first gripping portion 21 moves rightward to approach the work W from the left side, and the second gripping portion 22 moves leftward to approach the work W from the right side. move in the direction

The first gripping portion 21 is provided at a contact portion with the workpiece W to be gripped, and extends in a direction non-perpendicular to the moving direction of the first gripping portion 21 and the second gripping portion 22. A sliding portion 211 is provided. As shown in FIG. 8B, the first sliding portion 211 extends in a direction that intersects the left-right direction, which is the moving direction of the first gripping portion 21 and the second gripping portion 22, at a non-perpendicular angle. 8(B) before the gripping device 20 grips the work W, the work W is on the first conveyor C1 (FIG. 2) for conveying in the horizontal plane. The first sliding portion 211 of the portion 21 also extends in the horizontal plane.

The first sliding portion 211 is made of, for example, a self-lubricating material. Alternatively, the first sliding portion 211 may be made of a porous material and a lubricant may be added thereto. In addition, unevenness may be formed on the surface of the first sliding portion 211 along the direction in which the workpiece W slides. It is preferable that the height difference between the protrusions and recesses of the unevenness is 0.1 mm or more.

A second sliding portion 221 is provided on the second gripping portion 22 as well as the first gripping portion 21 . The first sliding portion 211 and the second sliding portion 221 are non-parallel to each other, and as shown in FIGS. 8B and 8C, expand upward from below. Although it is preferable to provide sliding portions on both the first gripping portion 21 and the second gripping portion 22 in order to smoothly slide the workpiece W, only one of the gripping portions 21 and 22 is provided with a sliding portion. may

As shown in FIG. 8(C), the workpiece W gripped from both sides by the first gripping portion 21 and the second gripping portion 22 moves in the direction in which the first sliding portion 211 and the second sliding portion 221 expand. slide to. That is, the forces applied to the work W from the left and right directions by the first gripping portion 21 and the second gripping portion 22 are changed in direction by the first sliding portion 211 and the second sliding portion 221 intersecting the left and right directions at a non-perpendicular angle. , to move the workpiece W upward in the expanding direction. Due to this force, the workpiece W smoothly slides upward while contacting the first sliding portion 211 and the second sliding portion 221 .

The workpiece W is stopped by contacting the first flange portion 213 and the second flange portion 223 as stopping portions at its sliding ends. As shown in FIG. 8(C), the first flange portion 213 protrudes from the upper end of the first sliding portion 211 toward the second grip portion 22, and the second flange portion 223 protrudes from the second sliding portion. It protrudes in a direction from the upper end of 221 toward the first grip portion 21 . The work W moves upward from FIG. 8B to FIG. 8C, but in FIG. Stop. E1 and E2 represent sliding ends of the sliding portions 211 and 221, respectively. The workpiece W is securely gripped by the first gripping portion 21 and the second gripping portion 22 at this position. The first flange portion 213 and the second flange portion 223 are provided with a first receiving portion 214 and a second receiving portion 224 that match the shape of the work W so that the work W can be securely gripped. As shown in the drawing, when the workpiece W is cylindrical, the first receiving portion 214 and the second receiving portion 224 are configured as arcuate curved surfaces.

According to the above configuration, final positioning and gripping of the workpiece W are performed by the sliding portions 211, 221 and the flange portions 213, 223. The workpiece W can be securely gripped. In order to make the most of the advantages peculiar to this embodiment, the gripping device 20 grips the workpiece W by the flexibility imparting parts such as the speed reducer 34, the elastic member 35, and the resistance imparting member provided in each joint. The flexibility of the joint may be increased.

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that the embodiments are examples, and that various modifications can be made to combinations of each component and each treatment process, and such modifications are also within the scope of the present invention.

Although the first sliding portion 211 and the second sliding portion 221 extend linearly in the embodiment, they may extend curvedly. In this case, if the tangential direction at each point where the sliding portion contacts the workpiece W is a direction that intersects the moving direction of the first gripping portion 21 and the second gripping portion 22 at a non-perpendicular angle, the workpiece W moves smoothly over the sliding portion. can slide to

In the embodiment, both the first sliding portion 211 and the second sliding portion 221 are inclined in a direction non-perpendicular to the direction of movement of the first gripping portion 21 and the second gripping portion 22. Either one of the sliding portions may extend in a direction orthogonal to the moving direction of the first gripping portion 21 and the second gripping portion 22 . Further, when the extending direction of one of the first gripping portion 21 and the second gripping portion 22 is orthogonal to the moving direction and the extending direction of the other crosses the moving direction at a non-perpendicular angle, the sliding portion is It may be provided only on one gripping portion or may be provided only on the other gripping portion.

Note that the functional configuration of each device described in the embodiments can be realized by hardware resources, software resources, or cooperation between hardware resources and software resources. Processors, ROMs, RAMs, and other LSIs can be used as hardware resources. Programs such as operating systems and applications can be used as software resources.

20 gripping device 21 first gripping part 22 second gripping part 30 connecting device 34 speed reducer 35 elastic member 41 first link 42 second link 100 robot arm 211 first sliding part 213 1st flange part, 221 2nd sliding part, 223 2nd flange part.

Claims (13)

a first gripping portion movable with respect to a gripping target;
a second gripping portion capable of gripping the gripping target between itself and the first gripping portion;
Sliding provided at a contact portion of at least one of the first gripping portion and the second gripping portion with the gripped object, and extending in a direction non-perpendicular to and intersecting the moving direction of the first gripping portion. Department and
a stopping portion with which the object to be grasped that has slid to the sliding end of the sliding portion contacts and stops;
A grasping device comprising: The sliding portion includes a first sliding portion provided on the first gripping portion and a second sliding portion non-parallel to the first sliding portion provided on the second gripping portion,
The object to be grasped slides in a direction in which the first sliding portion and the second sliding portion expand while being grasped by the first grasping portion and the second grasping portion.
A gripping device according to claim 1 . 3. Grasping device according to claim 1 or 2, wherein the slide extends in a horizontal plane. 4. A gripping device according to any preceding claim, wherein the slide extends in a vertical plane. 5. The gripping device according to any one of claims 1 to 4, wherein said second gripping part is movable in a direction opposite to said first gripping part. 6. A gripping device according to any preceding claim, wherein the stop is a flange provided at the slide end. 7. Grasping device according to any one of claims 1 to 6, wherein the slide is formed from a self-lubricating material. 8. Grasping device according to any of claims 1 to 7, wherein the slide is lubricated. The grasping device according to any one of claims 1 to 8, wherein the surface of the sliding portion is formed with unevenness along the direction in which the grasped object slides. 10. The gripping device according to claim 9, wherein the height difference between the protrusions and recesses of the unevenness is 0.1 mm or more. a first link;
a second link;
a joint that connects the first link and the second link so as to allow relative movement;
a flexibility imparting portion that imparts flexibility to the joint;
In a gripping device attached to the first link or the second link, a first gripping portion movable with respect to a gripping object and a second gripping portion capable of gripping the gripping object between the first gripping portion Provided at a contact portion between the gripping portion and the gripped object of at least one of the first gripping portion and the second gripping portion, and extending in a direction non-perpendicular to the direction of movement of the first gripping portion a gripping device comprising: a sliding portion that is present, and a stopping portion that the object to be gripped that has slid to the sliding end of the sliding portion contacts and stops;
A robot arm with 12. The robot arm according to claim 11, wherein said flexibility imparting portion is constituted by a series elastic actuator. 13. The robot arm according to claim 12, wherein said series elastic actuator increases the flexibility of said joint when said gripping device grips said gripping target.

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