JP7134085B2 - Gripping device and gripping method - Google Patents

Description

The present invention relates to a gripping device and a gripping method for gripping a plate-shaped work.

A gripping device is sometimes used in order to reduce the manual burden when removing the plate-shaped work from the supply position. For example, the gripping device has a pair of clamping pieces that can be moved toward and away from each other. Both clamping pieces are arranged opposite to each other in the width direction along the plate surface of the work in a state in which the plate-shaped work is placed vertically, and come close to each other and abut against the outer peripheral surface (thickness portion) of the work, It works like holding a workpiece.

If the gripping device is an end effector attached to a robot arm, the workpiece can be transported from the supply position to the assembly position by driving the robot arm.

However, if a plate-shaped work is tilted and the robot cannot recognize the tilt of the work, the work cannot be taken out, or even if it can be taken out, the work may drop during transport or the transport destination may be damaged. A problem arises in that a work assembly failure occurs. On the other hand, Patent Literature 1 discloses a technique for controlling a robot based on information from a line sensor. If the robot side can recognize the inclination of the work using this technology, it is possible to take out the work.

JP 2014-172122 A

However, there is a concern that the structure of the gripping device will become complicated due to the provision of a detection means such as a line sensor, and it is desired to deal with this by a simpler method.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gripping device and a gripping method capable of gripping a workpiece in a proper posture.

A gripping device of the present invention includes a pair of holding portions and a posture correction portion. A pair of clamping portions are arranged on both sides in the width direction along the plate surface of the work in a state in which the plate-shaped work is placed vertically, with the work in between, and are arranged so as to face each other and approach the plate thickness portion of the work. and grips the workpiece. The posture correcting portion is arranged between the pair of holding portions in the width direction, contacts the plate surface of the work, and corrects the work to a vertically standing posture.

A gripping method according to the present invention includes placing a pair of clamping portions facing each other on both sides in a width direction along a plate surface of a vertically placed plate-shaped work with the work in between, and In the width direction, a posture correction section is arranged between the pair of holding sections and at a position rearwardly separated from the rear plate surface of the work, and further at a position rearwardly separated from the rear plate surface of the work. A second posture correcting portion protruding toward each other from the pair of holding portions is arranged, and while the pair of holding portions are in a separated state , the posture correcting portion and the second posture correcting portion are connected to the workpiece. is approached from the rear and brought into contact with the plate surface on the rear side of the work, the work is pushed forward to correct the upright posture, and then, from the separated state, the pair of holding parts are moved toward each other. Then, the pair of holding portions are brought into contact with the plate thickness portion of the work corrected to the upright posture, so that the pair of holding portions hold the work.

When a plate-shaped work is tilted from the vertical direction, the posture corrector contacts the plate surface of the work and corrects the work to an upright posture. can be held between Therefore, the work can be gripped in a proper posture with a simple configuration without relying on detection means such as a sensor, thereby saving manpower and reducing the work load.

The gripping device of the present invention has a second posture correcting section that protrudes toward each other from the side of the pair of clamping sections and contacts the plate surface of the workpiece . According to this, since the second posture correcting portion abuts on the plate surface of the work in addition to the posture correcting portion, it is possible to improve the reliability of correcting the inclination of the work.

For example, if the gripping device is an end effector mounted on a robot arm, after picking up the work, the work can be converted into a horizontal posture, and the work in the horizontal posture can be transported to the assembly position. In this case, the workpiece in the horizontal posture can be stably supported from below by the posture correction section and the second posture correction section.

In the case of the gripping device of the first aspect of the present invention, the posture correcting section and the second posture correcting section have contact surfaces that contact the plate surface of the work within the same plane. According to this, it is possible to satisfactorily achieve a state in which the contact surfaces of the posture correcting portion and the second posture correcting portion are both brought into contact with the plate surface of the workpiece.
A gripping device according to a second aspect of the present invention is a gripping device to be attached to a robot arm, wherein a plate-shaped work is placed vertically, and the work is placed on both sides in the width direction along the plate surface of the work. A pair of nipping portions that are arranged to face each other in between, approach each other from a separated state, abut on the plate thickness portion of the work, and hold the work therebetween, and are arranged between the pair of nipping portions in the width direction. and a posture correcting portion that abuts on the rear side plate surface of the work, and a second posture correction portion that protrudes toward each other from the pair of holding portions side and abuts on the rear side plate surface of the work. and, when the pair of holding parts are in the separated state, the gripping device advances based on the driving of the robot arm, and the posture correcting part and the second posture correcting part move toward the workpiece. The gripping device is configured to press the rear side plate surface forward to correct the work to a vertically standing posture.

FIG. 2 is a perspective view of the gripping device and the workpiece in the first state as viewed obliquely downward and forward in the first embodiment; FIG. 4 is a perspective view of the gripping device and the workpiece in the first state as seen obliquely from below; It is a front view of a gripping device and a workpiece in a first state. FIG. 10 is a front view of the gripping device and the workpiece in a second state; FIG. 11 is a front view of the gripping device and the workpiece in a fourth state; It is a side view of a gripping device and a workpiece in a first state. FIG. 10 is a side view of the gripping device and workpiece in a second state; FIG. 11 is a side view of the gripping device and the workpiece on the way to the third state; FIG. 10 is a side view of the gripping device and workpiece in a third state; FIG. 10 is a cross-sectional view of the gripping device and the workpiece in a third state;

<Embodiment 1>
Embodiment 1 will be described based on FIGS. 1 to 10. FIG. The gripping device 10 of Embodiment 1 is an end effector of an articulated robot. The gripping device 10 grips the work 60, transports the work 60 by driving the robot arm, releases the grip of the work 60 at a predetermined assembly position, and sets the work 60 to the assembly target at the assembly position. .

In the case of Embodiment 1, the workpiece 60 is configured as an oil seal provided inside the hydraulic shock absorber. An oil seal as a work 60 includes an annular base metal 61 and a lip 62 having a seal lip and a dust lip, which is provided on the inner peripheral side of the base metal 61 and is in sliding contact with the outer periphery of the piston rod.

A pallet case 80 schematically indicated by a two-dot chain line in FIGS. The pallet case 80 has an accommodation groove 81 in which the work 60 can be accommodated vertically. A plurality of storage grooves 81 are provided in parallel in the pallet case 80, opening upward in a slit shape (only one storage groove 81 is shown in FIGS. 6 to 10). A wide variety of works 60 having different thicknesses can be accommodated in the accommodation groove 81 . Therefore, the groove width of the accommodation groove 81 is set to correspond to the thickest workpiece. The workpiece 60 is accommodated in the accommodation groove 81, the center of gravity is biased toward the rear side (left side in FIG. 6) where the lip 62 protrudes, and the plate surface is tilted rearward with respect to the vertical direction (vertical direction). can be The work 60 in the tilted state is corrected to an upright posture by the posture corrector 15 described later.

Next, the structure of the gripping device 10 will be specifically described. As shown in FIGS. 1 and 2, the gripping device 10 includes an attachment 11 attached to the terminal end of the robot arm, a housing 12, a cylinder body 13, a pair of holding portions 14, and a posture correction portion 15. FIGS. 1 and 2 show a state (first state described later) immediately before the gripping device 10 performs the work of gripping the work 60 supplied to the supply position. In the following description, the vertical direction is based on FIGS. 1 and 2, and the front-rear direction is on the right side in FIGS.

The housing 12 is formed substantially rectangular. The attachment 11 is arranged on the front side of the housing 12 , and the cylinder body 13 is arranged on the bottom side of the housing 12 .

The attachment 11 has a cylindrical shape and is rotatable about a front-rear rotation axis (a dashed line in FIG. 1) at the end of the robot arm. The attachment 11 is connected to the housing 12 via a plate-like relay portion 16 . The relay portion 16 has a flat plate 17 fixed facing the upper surface of the housing 12 .

The cylinder body 13 has a substantially rectangular parallelepiped shape, has a piston inside, and has a port penetrating inside and outside. An air conduit 22 is attached to the cylinder body 13 via an adapter 21 connected to a port.

A guide 23 is provided on the lower surface side of the cylinder body 13 . The guide 23 is formed in the shape of a rail extending linearly in the front-rear direction on the lower surface side of the cylinder body 13 .

The pair of clamping portions 14 are supported by the guide 23 on the lower surface side of the cylinder body 13 so as to be slidable, and are spaced apart in the width direction (the direction along the plate surface of the workpiece 60 and the left-right direction in FIGS. 3 to 5). are arranged side by side. The piston is connected to the holding portion 14 inside the cylinder body 13 and reciprocates in the width direction. Both clamping portions 14 move parallel (opening/closing drive) in directions of approaching and separating from each other (opening/closing) while being guided by a guide 23 in response to a piston operated by compressed air supplied and exhausted from an air conduit 22 through a port. can do.

As shown in FIG. 3, both clamping portions 14 include arm portions 24 that protrude downward and are arranged in pairs in the width direction, and plate-like grasping portions that protrude from the lower ends of the arm portions 24 in directions approaching each other. a portion 25; The grip portion 25 is separate from the arm portion 24 and is connected to the arm portion 24 .

The gripping portions 25 forming a pair in the width direction are positioned on the rear side in the thickness direction of the opposing surface of the base portion 26 connected to the both gripping portions 14 (the back side of the paper surface of FIG. 3) and face each other. and a second posture corrector 27 projecting outward. The base 26 has a groove 29 with an arcuate cross section on the front side in the thickness direction (the front side of the paper surface of FIG. 3) of the opposing surface, and a gripping surface 28 that tapers upward and downward from the groove 29 and spreads on both sides. have. A gripping surface 28 of the base portion 26 can contact the outer peripheral surface (thickness portion) of the base metal 61 of the workpiece 60 .

The second posture correcting portion 27 has a flat plate shape with a substantially rectangular outline when viewed from the front. 31. The contact surface 31 of the second posture corrector 27 is formed flat along the vertical direction.

The gripping portion 25 has a recessed portion 32 (see FIG. 2) defined by the contact surface 31 of the second posture correction portion 27 and the gripping surface 28 of the base portion 26 . Outer peripheral portions 63 at both ends in the width direction from the outer peripheral surface to the plate surface (rear surface) of the work 60 are accommodated in the recesses 32 .

A plate-shaped mounting portion 34 is mounted on the rear side of the cylinder body 13 . The mounting portion 34 is formed in a vertical plate shape that covers the entire rear surface of the cylinder body 13 and protrudes downward from the cylinder body 13 .

A horizontal plate-shaped connecting portion 35 that bends and protrudes forward is connected to the widthwise central portion of the lower end of the mounting portion 34 .
The posture correcting portion 15 has a vertical plate shape that bends and protrudes downward from the front end of the connecting portion 35 , and is connected with the same width as the connecting portion 35 . The posture correcting portion 15 is arranged between the holding portions 14 and above the holding portion 25 in the width direction, which is the moving direction of the holding portions 14 .

The front surface of the posture corrector 15 is configured as a contact surface 37 capable of contacting the plate surface of the workpiece 60 (the rear surface of the base metal 61). The contact surface 37 of the posture corrector 15 is formed flat along the vertical direction. As shown in FIGS. 6 and 7, the contact surface 37 of the posture correcting portion 15 and the contact surfaces 31 of both the second posture correcting portions 27 are substantially arranged in parallel at the same position.

Next, the action of the gripping device 10 will be described.
The gripping device 10 is made to stand by at a predetermined position with the pair of gripping portions 14 protruding downward. The work 60 is stored vertically in the storage groove 81 of the pallet case 80 and set at the supply position. Here, the workpiece 60 is in a state in which the upper portion thereof is tilted rearward in the vertical direction in the accommodation groove 81 of the pallet case 80 .

Subsequently, the gripping device 10 is moved to the supply position based on the driving of the robot arm and installed in the first state shown in FIGS. 1 to 3 and 6. FIG. The robot arm is controlled by a control mechanism and can change the position and orientation of the grasping device 10 via the attachment 11 .

When the gripping device 10 is in the first state, both clamping portions 14 are arranged above the work 60 and on both sides in the width direction of the work 60 away from the work 60. It is arranged apart from the workpiece 60 above the direction center part. Further, the contact surfaces 37 and 31 of the posture correcting portion 15 and both of the second posture correcting portions 27 are arranged behind the workpiece 60 in the front-rear direction.

Then, the gripping device 10 is lowered from the first state and placed in the second state shown in FIGS. 4 and 7 based on the driving of the robot arm.

When the gripping device 10 is in the second state, both clamping portions 14 are arranged on both sides of the work 60 in the width direction away from the work 60, and both second posture correcting portions 27 are arranged on both ends of the work 60 in the width direction. , and the contact surfaces 31 are arranged behind both ends of the workpiece 60 in the width direction. The posture corrector 15 overlaps the upper end of the work 60 in the vertical direction, and the contact surface 37 is arranged behind the upper end of the work 60 .

Then, the grasping device 10 is advanced from the second state and placed in the third state shown in FIGS. 9 and 10 based on the driving of the robot arm.

While the gripping device 10 is moving to the third state, as shown in FIG. The second posture correcting portion 27 abuts on the plate surfaces at both ends in the width direction of the work 60 (rear surfaces at both ends in the width direction of the base metal 61). In this manner, the posture correcting portion 15 and both of the second posture correcting portions 27 abut on the plate surface of the workpiece 60 at three locations that are equally spaced at 90 degrees in the circumferential direction.

Further, when the gripping device 10 is moved forward to reach the third state, the posture correcting section 15 and both the second posture correcting sections 27 push forward the work 60 in the inclined state, and move the work 60 to the lower end portion. is tilted forward as a fulcrum, leading to a posture of standing almost vertically in the vertical direction.

Next, without moving the gripping device 10 as a whole, both clamping portions 14 are parallel-moved along the guide 23 in a direction toward each other by air drive, resulting in the fourth state shown in FIG. In the fourth state, the gripping surfaces 28 of the bases 26 of the two clamping portions 14 are in contact with the regions of the outer peripheral surface of the work 60 at both ends in the width direction and at the center in the vertical direction, and are directed toward the center of the work 60. gripping force on the same axis. At this time, since the work 60 is corrected to the standing posture by the posture correcting section 15 and the second posture correcting section 27, a state is realized in which both the clamping sections 14 are brought into contact with the region of the outer peripheral surface of the work 60. . Further, in the fourth state, the outer peripheral portion 63 of the work 60 is accommodated in the recessed portion 32 of the gripping portion 25 of both clamping portions 14 . As a result, both second holding portions 14 can hold the work 60 stably.

After that, the gripping device 10 is moved to an assembly position away from the supply position based on the driving of the robot arm. In the gripping device 10, the postures of both clamping portions 14 are changed sideways before reaching the assembly position. Therefore, the workpiece 60 gripped by both clamping portions 14 is converted into a horizontal posture in which the plate surface is aligned in the horizontal direction, and is set in the horizontal posture as an assembly target at the assembly position. The posture correcting portion 15 and both of the second posture correcting portions 27 can contact the plate surface (lower surface) of the work 60 from below after the work 60 is converted to the horizontal posture. Therefore, both the posture correction section 15 and the second posture correction section 27 can stably support the workpiece 60 in the horizontal posture.

As described above, according to the first embodiment, when the plate-like work 60 is tilted in the vertical direction, the posture correction unit 15 contacts the plate surface of the work 60 to move the work 60 along the vertical direction. Since the work 60 is corrected to the standing posture, both holding portions 14 can properly hold the workpiece 60 in the standing posture. Therefore, without relying on detection means such as a sensor, the work 60 can be automatically taken out in a proper posture with a simple configuration, and manpower saving and work load reduction can be achieved. Since both the holding portions 14 and the posture correcting portion 15 do not contact the lip 62 on the inner peripheral side of the workpiece 60, the sealing performance of the lip 62 can be maintained.

In addition to the posture correcting portion 15 , the gripping device 10 has a second posture correcting portion 27 that protrudes toward each other from the side of the pair of holding portions 14 and contacts the plate surface of the workpiece 60 . In addition to the posture correcting portion 15, both the second posture correcting portions 27 also contact the plate surface of the work 60, so the reliability of correcting the tilt of the work 60 can be enhanced.

In the case of the first embodiment, the workpiece 60 is converted into a horizontal posture during the transportation process. Here, the posture correcting section 15 and the second posture correcting section 27 can stably support the workpiece 60 in the horizontal posture from below.

Since the posture correcting portion 15 and both of the second posture correcting portions 27 have the contact surfaces 37 and 31 contacting the plate surface of the work 60 in the same plane along the vertical direction, the work 60 is kept flat. A state in which both the contact surfaces 37 and 31 are in contact with the flat plate surface can be satisfactorily realized.

Since both clamping portions 14 move toward the center of the work 60 and apply a gripping force to the center of the work 60, the work 60 can be stably gripped between the two clamping portions 14 with good balance.

The present invention is not limited to the first embodiment explained by the above description and drawings, and the following embodiments are also included in the technical scope of the present invention.
(1) The workpiece is not limited to an oil seal, and may be a plate-shaped member such as a cover member. Moreover, the work is not limited to the part of the hydraulic shock absorber.
(2) The workpiece may have a plate-like shape that can be placed vertically, for example, it may be formed in a rectangular plate shape.
(3) A work-side member such as a pallet case for accommodating the work may approach the posture correcting section, and the posture correcting section may come into contact with the plate surface of the work to correct the work to an upright posture.
(4) The gripping device is not limited to the end effector attached to the robot arm, and may be incorporated in a mechanical structure incorporating a link mechanism or the like.
(5) The driving source for moving the pair of holding portions is not limited to the air cylinder, and may be an electric driving source.
(6) Various sensors can be attached to the gripping device.
(7) The gripping method only needs to have a step of holding the workpiece between the pair of gripping portions, and the step of transporting the workpiece to the assembly position can be omitted.
(8) The gripping method consists of the timing at which the posture correcting portion contacts the plate surface of the work to correct the work to the upright posture, and the timing at which the two clamping portions approach each other and the outer peripheral surface (thickness of the plate) of the work. The timing at which the fourth state of holding the workpiece by contacting the part) may be set with almost no time difference.

DESCRIPTION OF SYMBOLS 10... Grasping device 13... Cylinder body 14... Holding part 15... Posture correcting part 25... Gripping part 27... Second posture correcting part 31... Contact surface of the second posture correcting part 37... Abutting surface of the posture correcting part 60 Workpiece

Claims (4)

With a plate-shaped work placed vertically, the plate-shaped work is placed on both sides in the width direction along the plate surface of the work, with the work in between, and comes close to each other and comes into contact with the plate thickness of the work. , a pair of clamping portions that clamp and hold the workpiece;
a posture correcting portion disposed between the pair of holding portions in the width direction, abutting against the plate surface of the work, and correcting the work to a vertically standing posture;
a second posture correcting part that protrudes toward each other from the pair of holding parts and abuts on the plate surface of the workpiece;
The posture correcting section and the second posture correcting section have contact surfaces on the same plane that contact the plate surface of the workpiece. A gripping device attached to a robot arm, comprising:
In a state where a plate-shaped work is placed vertically, it is arranged on both sides in the width direction along the plate surface of the work, with the work in between, and the plate thickness portions of the work approach each other from the separated state. A pair of clamping portions that are in contact with and clamp the workpiece;
a posture correcting portion disposed between the pair of holding portions in the width direction and in contact with the plate surface on the rear side of the work;
a second posture correcting part protruding from the pair of holding parts in a direction toward each other and abutting on the rear plate surface of the work;
When the pair of holding parts are in the separated state, the gripping device advances based on the driving of the robot arm, and the posture correcting part and the second posture correcting part move toward the plate surface on the rear side of the workpiece. forwardly to correct the work to a vertically standing posture. 3. The gripping device according to claim 2, wherein the posture correcting portion and the second posture correcting portion have contact surfaces on the same plane that contact the plate surface of the workpiece. With respect to a plate-like work placed vertically, a pair of holding portions are arranged on both sides in the width direction along the plate surface of the work with the work in between, and the pair of holding portions are arranged in the width direction. A posture correcting section is arranged between the sections and at a position rearwardly separated from the rear plate surface of the work, and further at a position rearwardly separated from the rear plate surface of the work from the pair of clamping sections. arranging a second posture corrector protruding toward each other;
While the pair of holding parts are in the separated state, the posture correcting part and the second posture correcting part are brought closer to the work from behind and brought into contact with the back plate surface of the work to push the work forward. to correct to a vertical standing posture, and then
From the separated state, the pair of holding portions are moved toward each other, and the pair of holding portions are brought into contact with the plate thickness portion of the work corrected to the standing posture, so that the pair of holding portions hold the work. A gripping method that makes it possible to hold.

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