Grip device and industrial robot

Abstract

To provide a gripping body, a gripping device, and an industrial robot capable of preventing the gripping body from falling off from a case, as well as, preventing liquid pools from occurring.SOLUTION: A grip main body 28A includes: a palm portion 30; a plurality of finger portions 32 protruding around the palm portion 30, and tilting toward the palm portion 30 when the palm portion 30 is deformed in a thickness direction; and an opening portion 34 provided on the other side opposite to one end side where the palm portion 30 and the plurality of finger portions 32 are provided. The opening portion 34 includes: an open end 50 defining an opening; and an inner surface 51 curved directed toward a center of the opening. The gripping device 10A includes: the gripping main body 28A; and a case 40A including a bottom portion 41, a tubular portion 42A provided on an outer edge of the bottom portion 41, and a corner portion 43 connecting the bottom portion 41 and the tubular portion 42A, and inserted into the opening portion 34. The corner portion 43 includes an outer surface 52 curved toward a center of the case 40A. The inner surface 51 and the outer surface 52 are in contact with each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gripping body, a gripping device, and an industrial robot. [Background technology]

[0002] A known gripping device for gripping a workpiece includes a bag-shaped gripping body (see Patent Document 1). The gripping body of the gripping device disclosed in Patent Document 1 has a palm portion and multiple fingers protruding from the periphery of the palm portion. The gripping body has an opening at the other end opposite the end where the palm portion and fingers are provided. The gripping body is fixed to a case at a flange formed around the opening, and the opening is sealed by the case. The case is connected to a vacuum generator via piping. When the pressure inside the gripping body is reduced, the gripping device disclosed in Patent Document 1 deforms in the thickness direction of the palm portion, causing the multiple fingers to elastically deform and collapse toward the palm portion. This allows the multiple fingers to contact the surface of the workpiece and grip the workpiece. This allows for easy and gentle gripping of soft workpieces, such as food.

[0003] Patent Document 2 discloses a gripping device in which a band is wrapped around the outer periphery of the gripping body, and the gripping body and case are more securely fixed by fastening the band. The gripping device of Patent Document 2 has a structure in which the gripping body and case are fastened with the band, and therefore prevents the gripping body from falling off the case when the fingers elastically deform so as to fall toward the palm as the palm deforms in the thickness direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-062038 [Patent Document 2] Japanese Patent Application Publication No. 2019-150892 Summary of the Invention [Problem to be solved by the invention]

[0005] The gripping device according to Patent Document 2 has a step formed between the band and the gripping body, which makes it easy for liquid to pool at this step. Liquid pools are unhygienic because they can cause mold to grow. The gripping device according to Patent Document 1 has a step formed between the flange formed around the opening of the gripping body and the case, which makes it easy for liquid to pool, just like Patent Document 2.

[0006] An object of the present invention is to provide a gripping body, a gripping device, and an industrial robot that prevent the gripping body from falling off the case and prevent liquid pooling from occurring. [Means for solving the problem]

[0007] The gripping body according to the present invention is a bag-shaped gripping body used in a gripping device that grips a workpiece, and comprises a palm portion, a plurality of finger portions that protrude from the periphery of the palm portion and fall toward the palm portion by deforming the palm portion in the thickness direction, and an opening provided on the other end opposite to the end where the palm portion and the plurality of finger portions are provided, and the opening has an opening edge that defines the opening and an inner surface that curves toward the center of the opening.

[0008] The gripping device of the present invention comprises a case that is inserted into the opening and has the gripping body, a bottom, a cylindrical portion provided on the outer edge of the bottom, and a corner portion connecting the bottom and the cylindrical portion, wherein the corner portion has an outer surface that curves toward the center of the case, and the inner surface and the outer surface are in contact.

[0009] An industrial robot according to the present invention includes the above-described gripping device. [Effects of the Invention]

[0010] According to the present invention, the opening of the grip body has an inner surface curved toward the center of the opening, the corners of the case have outer surfaces curved toward the center of the case, and the inner surface of the opening and the outer surface of the corners are in contact with each other, so that the grip body does not fall off the case and liquid accumulation can be prevented. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating an example of an industrial robot to which a gripping device according to an embodiment is applied. [Figure 2] FIG. 2 is a partial cross-sectional view showing a gripping device according to an embodiment. [Figure 3] FIG. 10 is a perspective view showing a state in which the case is being removed from the opening of the grip body. [Figure 4] FIG. 10 is a cross-sectional view showing a state in which the case is being removed from the opening of the grip body. [Figure 5] FIG. 10 is a cross-sectional view showing a state in which the case is inserted into the opening of the grip body. [Figure 6] FIG. 2 is a partial cross-sectional view showing a state in which the gripping device according to the embodiment is in use. [Figure 7] FIG. 10 is an exploded perspective view showing a gripping device according to a modified example of the embodiment. [Figure 8] FIG. 10 is a partial cross-sectional view showing a gripping device according to a modified example of the embodiment. [Figure 9] FIG. 10 is a partial cross-sectional view showing a state in which a gripping device according to a modified example of the embodiment is used. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments and modifications shown below are examples of the present invention, and the present invention is not limited thereto. In the following description of the embodiments and modifications, similar components are designated by similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0013] 1. Embodiment (Overall composition) 1 shows the configuration of an industrial robot 12 to which a gripping device 10A according to this embodiment is applied. The industrial robot 12 is a Cartesian robot, and includes a rail 14, a moving body 16 that moves along the rail 14, and an air cylinder 18 fixed to the moving body 16. The rail 14 is provided so as to be movable in the Y-axis direction in the drawing.

[0014] The air cylinder 18 has a cylinder tube 19 and a piston rod 20 that is provided so as to be able to advance and retreat relative to the cylinder tube 19. Pipes 21 and 22 are provided to the cylinder tube 19. Gas is supplied and exhausted through the pipes 21 and 22, allowing the piston rod 20 to advance and retreat relative to the cylinder tube 19. A gripping device 10A is provided at the tip of the piston rod 20 via a detachable part 24 that is connected to an adapter plate 23. The adapter plate 23 is fixed to the tip of the piston rod 20 with bolts (not shown).

[0015] The industrial robot 12 can grip a workpiece W placed on a horizontal base 26 with a gripping device 10A and move in the X-axis, Y-axis, and Z-axis directions.

[0016] FIG. 2 shows a partial cross-sectional view of the gripping device 10A. FIG. 2 shows the gripping device 10A detached from the detachable part 24. The gripping device 10A includes a bag-shaped gripping body 28A that is attached to the piston rod 20 via the detachable part 24. The gripping body 28A can be made of a material that is airtight, elastic, and flexible, such as natural rubber, synthetic rubber, or various elastomers. The material of the gripping body 28A does not necessarily have to be a single material, and may be a composite material made up of a combination of different materials. The hardness of the gripping body 28A, measured in accordance with the durometer hardness test (type A) of JIS K6253, is preferably approximately 60 to 90.

[0017] The grip body 28A comprises a palm portion 30, a plurality of finger portions 32 protruding from the periphery of the palm portion 30, and an opening 34 provided at the other end opposite the end where the palm portion 30 and the plurality of finger portions 32 are provided. The palm portion 30 is generally disk-shaped. The finger portions 32 are formed integrally with the palm portion 30, and two are provided to sandwich the palm portion 30. A predetermined gap is formed between the finger portions 32. Three or more finger portions 32 may be provided radially surrounding the palm portion 30.

[0018] The inner surface 32A of the finger portion 32 is formed integrally with the palm portion 30. The finger portion 32 is solid. The material of the finger portion 32 may be the same as or different from that of the palm portion 30, and it does not have to be uniform; it may be a composite material that combines different materials, or may contain additives such as fillers.

[0019] The opening 34 is sealed by the case 40 A. An internal space 29 is formed by the inner surface of the grip body 28 A and the case 40 A.

[0020] The case 40A is preferably made of a metal such as stainless steel or a hard resin such as plastic. The case 40A has a bottom 41, a cylindrical portion 42A provided on the outer edge of the bottom 41, and corner portions 43 connecting the bottom 41 and the cylindrical portion 42A. The bottom 41 is a plate-like member, and in this example, is formed in a disk shape. The cylindrical portion 42A is a cylindrical member, and in this example, is formed in a cylindrical shape. The bottom 41, the cylindrical portion 42A, and the corner portions 43 are integrally formed. The bottom 41 has a through-hole 44 that penetrates the bottom 41 in the thickness direction. A joint 45 is provided in the through-hole 44. The joint 45 is screwed to the bottom 41 via a sealing material 46. The joint 45 is detachably connected to the detachable portion 24 with a single touch.

[0021] The detachable part 24 is a one-touch joint, one end of which is connected to the adapter plate 23 and the other end of which is connected to the joint 45. The detachable part 24 is connected to the joint 45 when the joint 45 is inserted in the insertion direction, and is disconnected from the joint 45 when the release part 47 is pushed in the insertion direction. The detachable part 24 is not limited to a one-touch joint, and may be a joint that is connected to the joint 45 by a screw.

[0022] The detachable unit 24 is provided with an intake / exhaust port 48. The intake / exhaust port 48 is connected to one end of a pipe (not shown). The other end of the pipe is connected to a vacuum generator such as a vacuum pump or a vacuum ejector, for example, via a three-way valve. In this example, a vacuum pump is used as the vacuum generator. The three-way valve has a vacuum port, an intake / exhaust port, and an atmosphere release port. The vacuum port is connected to the vacuum pump, the intake / exhaust port is connected to the gripping device 10A, and the atmosphere release port is connected to the atmospheric pressure space. Gas flows from the internal space 29 to the vacuum pump and from the atmospheric pressure space to the internal space 29 through the pipe connected to the intake / exhaust port 48. The detachable unit 24 is fixed to the adapter plate 23 by screwing bolts into the adapter plate 23 through mounting holes (not shown) provided on the top surface.

[0023] The opening 34 of the grip body 28A has an opening edge 50 defining the opening and an inner surface 51 curved toward the center of the opening. The inner surface 51 of the opening 34 is a concave curved surface. The corner 43 of the case 40A has an outer surface 52 curved toward the center of the case 40A. The outer surface 52 of the corner 43 is a convex curved surface. The inner surface 51 of the opening 34 and the outer surface 52 of the corner 43 are in contact. The contact between the concave inner surface 51 of the opening 34 and the convex outer surface 52 of the corner 43 generates friction between the inner surface 51 and the outer surface 52, causing the opening 34 of the grip body 28A to be hooked onto the corner 43 of the case 40A. This allows the grip body 28A to be attached to the case 40A without using a band. From the perspective of preventing the grip body 28A from falling off, it is desirable for the entire inner surface 51 of the opening 34 and the entire outer surface 52 of the corner 43 to be in contact with each other. As long as at least a portion of the inner surface 51 of the opening 34 and at least a portion of the outer surface 52 of the corner 43 are in contact with each other, the grip body 28A can be attached to the case 40A.

[0024] The thickness of the opening 34 gradually decreases toward the open end 50 of the opening 34. That is, the thickness of the opening 34 gradually decreases from one end side of the grip body 28A toward the other end side. As a result, the grip device 10A has no step between the opening 34 of the grip body 28A and the bottom 41 of the case 40A, and the opening 34 and the bottom 41 are smoothly connected.

[0025] The inner surface 51 of the opening 34 and the outer surface 52 of the corner 43 are both rounded fillets. When the case 40A is inserted into the opening 34, the curvature of the inner surface 51 of the opening 34 is the same as the curvature of the outer surface 52 of the corner 43. This brings the inner surface 51 of the opening 34 and the outer surface 52 of the corner 43 into contact over their entire surfaces, thereby improving the frictional force caused by the contact between the inner surface 51 and the outer surface 52. Note that the term "same" here does not only refer to a case where the curvature of the inner surface 51 of the opening 34 and the curvature of the outer surface 52 of the corner 43 are completely identical, but also includes a case where they are approximately identical, or within a predetermined error range (for example, an error range of about a few percent) taking into account design errors and the like.

[0026] Fig. 3 shows a perspective view of the case 40A being removed from the opening 34 of the grip body 28A. Fig. 4 shows a cross-sectional view of the case 40A being removed from the opening 34 of the grip body 28A. Fig. 5 shows a cross-sectional view of the case 40A being inserted into the opening 34 of the grip body 28A.

[0027] When case 40A is removed from opening 34, the curvature of inner surface 51 of opening 34 is greater than the curvature of outer surface 52 of corner 43 (see FIG. 4). When case 40A is inserted into opening 34, opening end 50 of opening 34 expands along the outer surface of tubular portion 42A of case 40A (see FIG. 5). When case 40A is inserted into opening 34, opening end 50 of opening 34 contracts along outer surface 52 of corner 43 of case 40A. As a result, inner surface 51 of opening 34 and outer surface 52 of corner 43 come into contact over their entire surfaces, and as described above, the curvature of inner surface 51 of opening 34 becomes the same as the curvature of outer surface 52 of corner 43 (see FIG. 2). When the case 40A is removed from the opening 34, the curvature of the inner surface 51 of the opening 34 is greater than the curvature of the outer surface 52 of the corner 43, so when the case 40A is inserted into the opening 34, the corner 43 of the case 40A is clamped by the opening 34 of the gripping body 28A.

[0028] (Action and effect) The operation and effects of the industrial robot 12 equipped with the gripping device 10A configured as described above will now be described. Note that the conditions shown below are merely examples. As shown in FIG. 1, the industrial robot 12 starts from an origin state in which the piston rod 20 is retracted into the cylinder tube 19 and the air cylinder 18 is contracted. In the initial state of the gripping device 10A, the pressure in the internal space 29 (see FIG. 2) of the gripping body 28A is atmospheric pressure. That is, the three-way valve connected to the intake and exhaust port 48 is in a state in which the intake and exhaust port is disconnected from the vacuum port and connected to the atmosphere release port.

[0029] The industrial robot 12 positions the gripping device 10A on the vertical line of the workpiece W placed on the base 26 by moving the movable body 16 along the rail 14. Next, the industrial robot 12 extends the air cylinder 18 by advancing the piston rod 20 from the cylinder tube 19 until the finger portion 32 reaches the workpiece W.

[0030] Next, the three-way valve is switched so that the intake / exhaust port is disconnected from the atmosphere release port and connected to the vacuum port, causing the gripping device 10A to suck in the gas from the gripping body 28A through the piping and reduce the pressure in the internal space 29 of the gripping body 28A to, for example, -0.03 MPa or less.

[0031] As shown in FIG. 6 , the palm portion 30 is deformed in the thickness direction (Z direction) as if being sucked into the internal space 29. As the palm portion 30 deforms in the thickness direction, the inner surfaces 32A of the fingers 32 are pulled toward the center of the palm portion 30. At this time, the inner surfaces 51 of the openings 34 and the outer surfaces 52 of the corners 43 rub against each other, and the opening edges 50 of the openings 34 move from the other end to one end of the gripping body 28A. As a result, the fingers 32 elastically deform so as to fall toward the palm portion 30 and come into contact with the surface of the workpiece W. In this way, the gripping device 10A reduces the pressure inside the gripping body 28A, causing the fingers 32 to close and grip the workpiece W.

[0032] Next, the industrial robot 12 retracts the piston rod 20 into the cylinder tube 19 and contracts the air cylinder 18, thereby lifting the workpiece W from the base 26. Furthermore, the industrial robot 12 can freely move the workpiece W in the horizontal direction by moving the movable body 16 along the rail 14 and by moving the rail 14 in the Y-axis direction.

[0033] After moving to the desired location, the industrial robot 12 extends the air cylinder 18 by extending the piston rod 20 from the cylinder tube 19 until the workpiece W contacts the base 26. Next, the three-way valve is switched so that the air supply / exhaust port is disconnected from the vacuum port and connected to the atmosphere release port. This allows gas to flow from the atmosphere release port through the piping into the internal space 29 of the gripping body 28A. As the pressure in the internal space 29 of the gripping body 28A returns to atmospheric pressure, the palm 30 is pushed out and returns to its original state. At this time, the inner surface 51 of the opening 34 rubs against the outer surface 52 of the corner 43, and the open end 50 of the opening 34 moves from one end to the other end of the gripping body 28A. This causes the fingers 32 to open and release the workpiece W.

[0034] Next, the industrial robot 12 retracts the piston rod 20 into the cylinder tube 19 and contracts the air cylinder 18, thereby separating the gripping device 10A from the workpiece W. In this manner, the industrial robot 12 can grip the workpiece W placed on the base 26 with the gripping device 10A and move it to a desired position.

[0035] In the gripping device 10A, the opening 34 of the gripping body 28A has an inner surface 51 that curves toward the center of the opening, and the corner 43 of the case 40A has an outer surface 52 that curves toward the center of the case 40A, with the inner surface 51 of the opening 34 and the outer surface 52 of the corner 43 being in contact. This causes the opening 34 of the gripping body 28A to be hooked onto the corner 43 of the case 40A, allowing the gripping body 28A to be attached to the case 40A without using a band. Furthermore, because a band is not used, there are no steps that could cause liquid to pool. Therefore, in the gripping device 10A, the gripping body 28A does not fall off the case 40A, and liquid pooling is prevented.

[0036] The gripping device 10A does not use a band, which reduces the number of parts and eliminates the need for a dedicated tool for fastening the band, thereby reducing manufacturing costs.

[0037] In gripping device 10A, opening 34 gradually becomes thinner toward opening end 50, so that opening 34 of gripping body 28A and bottom 41 of case 40A are smoothly connected. Since gripping device 10A has no step between gripping body 28A and case 40A, the occurrence of liquid pooling is more reliably prevented.

[0038] When case 40A is inserted into opening 34, the curvature of inner surface 51 of opening 34 is the same as the curvature of outer surface 52 of corner 43. In gripping device 10A, inner surface 51 of opening 34 and outer surface 52 of corner 43 come into contact over the entire surface, thereby improving the frictional force between inner surface 51 of opening 34 and outer surface 52 of corner 43, and more reliably preventing gripping body 28A from falling off case 40A.

[0039] When case 40A is removed from opening 34, the curvature of inner surface 51 of opening 34 is greater than the curvature of outer surface 52 of corner 43. When case 40A is inserted into opening 34, corner 43 of case 40A is fastened by opening 34 of grip body 28A, and as described above, the curvature of inner surface 51 of opening 34 becomes the same as the curvature of outer surface 52 of corner 43. In this way, grip device 10A more reliably prevents grip body 28A from falling off case 40A by fastening corner 43 of case 40A by opening 34 of grip body 28A.

[0040] 2. Variations Fig. 7 shows an exploded perspective view of a gripping device 10B according to a modified example of the above embodiment, in which a part of a gripping body 28B constituting the gripping device 10B is cut away.

[0041] 7, the gripping device 10B differs from the gripping device 10A (see FIG. 3) according to the above embodiment in that the gripping body 28B has a rib 60 and the case 40B has a groove 62 that engages with the rib 60. In the gripping device 10B, the gripping body 28B is positioned relative to the case 40B by the engagement between the rib 60 and the groove 62.

[0042] The rib 60 is provided on the inner surface of the grip body 28B. The rib 60 is formed in a ring shape along the circumferential direction of the grip body 28B. In this example, the shape of the rib 60 is semicircular in cross section, but this can be selected as appropriate, and may be, for example, semi-elliptical, triangular, rectangular, or trapezoidal in cross section.

[0043] Groove 62 is provided on the outer surface of cylindrical portion 42B that constitutes case 40B. Groove 62 is formed in an annular shape along the circumferential direction of cylindrical portion 42B. In this example, groove 62 has a rectangular cross section, but the shape can be selected appropriately and may be, for example, a rectangular cross section with rounded corners, a semicircular cross section, a semi-elliptical cross section, a triangular cross section, or a trapezoidal cross section.

[0044] 8, the width W1 of the rib 60 is smaller than the width W2 of the groove 62. The width W1 of the rib 60 may be, for example, equal to or smaller than half the width W2 of the groove 62. In this example, in the initial state, the rib 60 is disposed at the center position in the width direction of the groove 62. Since the width W1 of the rib 60 is smaller than the width W2 of the groove 62, movement of the rib 60 within the groove 62 is permitted.

[0045] As shown in Figure 9, when the action of gripping a workpiece is performed, that is, when the palm portion 30 deforms in the thickness direction (Z direction) and the fingers 32 elastically deform so as to fall toward the palm portion 30, the opening end 50 of the opening 34 of the gripping body 28B moves from the other end side to one end side of the gripping body 28B, and the rib 60 moves within the groove 62 from the other end side to one end side.

[0046] When the workpiece is released, i.e., when the palm portion 30 and the fingers 32 return to their original state, the opening end 50 of the opening 34 of the gripping body 28B moves from one end to the other end of the gripping body 28B, and the rib 60 moves from one end to the other end within the groove 62 and returns to its original position (see Figure 8).

[0047] In the gripping device 10B, the width W1 of the rib 60 is smaller than the width W2 of the groove 62, so that the rib 60 moves within the groove 62, allowing for smooth operation.

[0048] Although the embodiments and modifications have been described above, the present invention is not limited to the above-described embodiments and modifications, and can be modified as appropriate within the scope of the spirit of the present invention.

[0049] For example, the air intake / exhaust port 48 may be connected to a positive pressure source and a three-way valve via a switching valve. The positive pressure source may be a pump or the like that supplies positive pressure to the internal space 29. When the air intake / exhaust port 48 is connected to the positive pressure source, the internal space 29 can be pressurized. When the internal space 29 is pressurized by the positive pressure source, the palm portion 30 is deformed in the thickness direction (opposite the Z direction) as if being pushed from the internal space 29 toward the atmospheric pressure space. As the palm portion 30 deforms in the thickness direction, the fingers 32 elastically deform so as to collapse away from the palm portion 30. In other words, the fingers 32 can open. At this time, the inner surface 51 of the opening 34 rubs against the outer surface 52 of the corner 43, and the opening edge 50 of the opening 34 moves from one end of the grip body to the other. Pressurizing the internal space 29 allows the fingers 32 to open according to the size of the workpiece, improving versatility. [Explanation of symbols]

[0050] 10A,10B gripping device 12 Industrial robots 28A,28B Grip body 30 Palm 32 Finger section 34 Opening 40A, 40B case 41 Bottom 42A, 42B Cylindrical part 43 Corner 50 Open End 51 Inside 52 Exterior 60 Ribs 62 Groove

Claims

1. A bag-shaped gripping body used in a gripping device that grips a workpiece, A palm portion and a plurality of finger portions provided to protrude from the periphery of the palm portion and tilting toward the palm portion by deforming the palm portion in a thickness direction; an opening provided on the other end opposite to the one end where the palm portion and the plurality of finger portions are provided; Equipped with The opening includes a grip body having an open end defining an opening and an inner surface curved toward a center of the opening; a case having a bottom, a cylindrical portion provided on an outer edge of the bottom, and a corner portion connecting the bottom and the cylindrical portion, the case being inserted into the opening; Equipped with the corner has an outer surface that curves toward the center of the case; A gripping device in which the inner surface and the outer surface are in contact.

2. The gripping device according to claim 1 , wherein the opening has a thickness that gradually decreases toward the open end.

3. The gripping device according to claim 1 or 2, wherein the curvature of the inner surface is the same as the curvature of the outer surface when the case is inserted into the opening.

4. 4. The gripping device according to claim 1, wherein the curvature of the inner surface is greater than the curvature of the outer surface when the case is removed from the opening.

5. The grip body has a rib, The gripping device according to any one of claims 1 to 4, wherein the case has a groove that engages with the rib.

6. The gripping device according to claim 5 , wherein the width of the rib is smaller than the width of the groove.

7. An industrial robot comprising the gripping device according to any one of claims 1 to 6.

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