Robot hand and method for manufacturing robot hand

Abstract

This robot hand is provided with at least one finger, and the finger is provided with: a sheath that has a plurality of chambers, passages that communicate mutually adjacent chambers among the plurality of chambers, and recesses that are disposed between mutually adjacent chambers among the plurality of chambers; and a plurality of blocks disposed in the plurality of chambers.

Description

Technical Field

[0001] The present disclosure relates to a robot hand and a method for manufacturing the robot hand. Background Art

[0002] Conventionally, a robot hand having fingers whose shapes change according to fluid pressure has been proposed. Such a robot hand is disclosed in Patent Documents 1 and 2, for example.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2018-512304

[0006] Patent Document 2: Japanese Patent Application No. 2020-518478 Summary of the invention

[0007] Problems to be solved by the invention

[0008] A robot hand having fingers whose shapes change according to fluid pressure is required to have a desired shape in order to reliably grasp an object.

[0009] For example, if a fluid leaks out of a finger, there is a high possibility that the finger cannot be in an expected shape. Therefore, it is required to prevent the fluid from leaking out of the finger.

[0010] Furthermore, if the finger is deformed unexpectedly by external force before grasping the object, there is a possibility that the finger will change to an unexpected shape even if the fluid pressure is changed. In the above case, the finger will not be in the expected shape, and as a result, there is a possibility that the robot hand will not be able to grasp the object. Therefore, it is required that the finger does not deform even if an external force is applied, that is, the shape of the finger does not change except due to the change in fluid pressure.

[0011] Furthermore, if the expected shape cannot be maintained when holding an object, the holding force cannot be continuously applied to the object, and as a result, the possibility of failing to hold the object increases. Therefore, it is required that the finger maintains a shape that can apply the holding force to the object when holding the object.

[0012] An object of the present disclosure is to provide a robot hand having fingers that can assume a desired shape.

[0013] Means for solving problems

[0014] One embodiment of the robot hand disclosed herein is a robot hand having at least one finger.

[0015] Fingers have:

[0016] A sheath including a plurality of chambers, a passage connecting adjacent chambers among the plurality of chambers, and a recessed portion disposed between adjacent chambers among the plurality of chambers; and

[0017] A plurality of blocks are disposed in the plurality of chambers.

[0018] In addition, one embodiment of the method for manufacturing a robot hand of the present disclosure includes:

[0019] Prepare a plurality of blocks through which rods are inserted and a mold having a plurality of convex portions on the inner surface,

[0020] The plurality of blocks are arranged in a mold in a state where the plurality of blocks and the plurality of convex portions are arranged alternately.

[0021] Liquid resin is injected into the mold to wrap multiple blocks with the resin.

[0022] To cure the resin,

[0023] The plurality of blocks are left in the cured resin, and the rods are extracted from the plurality of blocks.

[0024] Effects of the Invention

[0025] According to the present disclosure, it is possible to provide a robot hand including fingers that can assume a desired shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a schematic diagram of a robot hand.

[0027] FIG. 2 is a schematic diagram of the robot hand holding an object.

[0028] FIG. 3 is a front view of the sheath.

[0029] FIG. 4 is a side view of the sheath.

[0030] FIG. 5 is a cross-sectional view taken along the line VV in FIG. 3 .

[0031] FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 4 .

[0032] FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 4 .

[0033] FIG. 8 is a front view of the block.

[0034] FIG. 9 is a side view of the block.

[0035] FIG10 is a cross-sectional view of a finger.

[0036] FIG. 11 is a cross-sectional view of a finger in a bent state.

[0037] FIG. 12 is a diagram showing the manufacturing process of the robot hand.

[0038] FIG. 13 is a diagram showing the manufacturing process of the robot hand.

[0039] FIG. 14 is a diagram showing the manufacturing process of the robot hand.

[0040] FIG. 15 is a diagram showing the manufacturing process of the robot hand. DETAILED DESCRIPTION

[0041] Hereinafter, the robot hand and the manufacturing method thereof according to the embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments shown below are merely illustrative. The present disclosure does not exclude the application of various modifications and technologies not explicitly shown in the following embodiments.

[0042] It should be noted that, in all the drawings for explaining the embodiments, the same elements are denoted by the same reference numerals in principle, and their description may be omitted. In addition, the scales of the drawings are not necessarily the same.

[0043] (The overall structure of the robot hand)

[0044] The entirety of a robot hand 1 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2 . FIG. 1 is a schematic diagram of a robot hand 1 according to an embodiment of the present disclosure. FIG. 1 shows a state in which an object 2 to be grasped by the robot hand 1 is placed on a placement surface 3. FIG. 2 is a schematic diagram of the robot hand 1 in a state in which the object 2 is grasped.

[0045] The robot hand 1 includes a base 10 and at least one finger 20. The robot hand 1 shown in FIG. 1 and FIG. 2 includes two fingers 20 arranged in a manner opposite to each other. In the following, the two fingers 20 are sometimes distinguished as a first finger 201 and a second finger 202 for explanation as needed. It should be noted that the number of fingers 20 included in the robot hand 1 may be one or more than three.

[0046] The base 10 includes a port 11. The port 11 is connected to a pipeline composed of a pipe, a tube, etc. A fluid pressure applying device such as a pump is connected to the pipeline.

[0047] The finger 20 is attached to the base 10. The finger 20 is an elongated member. The base end of the finger 20 is attached to the base 10. The tip of the finger 20 is arranged near the object 2 and can contact the object 2.

[0048] A space communicating with the port 11 and the finger 20 is formed inside the base 10. In addition, a space communicating with the internal space of the base 10 is formed inside the finger 20. The inside of the pipeline, the inside of the base 10, and the inside of the finger 20 are filled with fluid, and when the fluid pressure applying device applies pressure to the fluid in the pipeline, the pressure is transmitted to the fluid in the base 10 and the fluid in the finger 20. That is, the fluid pressure applying device can apply pressure to the fluid in the finger 20.

[0049] It should be noted that the fluid filling the tube, the base 10 and the finger 20 is, for example, air, water, or oil.

[0050] Furthermore, the base 10 is formed of a material (for example, metal or resin) having a rigidity to such an extent that the shape does not change even if the pressure of the fluid in the base 10 changes.

[0051] The finger 20 is configured such that, when the pressure of the fluid in the finger 20 is equal to the pressure outside the finger 20 (e.g., atmospheric pressure), the finger 20 is in a long strip shape extending along a straight line as shown in FIG. 1 . In addition, the finger 20 is configured such that, when the pressure of the fluid inside the finger 20 increases, the finger 20 bends as shown in FIG. 2 , and when the pressure of the fluid decreases, the finger 20 returns to its original shape. Hereinafter, the state in which the finger 20 is in a straight line shape is described as an initial state, and the state in which the finger 20 is in a bent shape is described as an operating state.

[0052] In addition, when the finger 20 is in the initial state, the straight line along which the finger 20 is located is set as the X-axis, and the direction from the base end toward the front end of the finger 20 is defined as the X-axis direction. In addition, two axes orthogonal to the X-axis are defined as the Y-axis and the Z-axis, and directions parallel to the Y-axis and the Z-axis are defined as the Y-axis direction and the Z-axis direction. The X-axis, the Y-axis, and the Z-axis constitute an orthogonal coordinate system. The finger 20 deforms along the XZ plane. In addition, a part that is a part of the finger 20 (referred to as one surface or the second surface) and can contact the object 2 is defined as the finger pulp (ventral surface) of the finger 20, and a part that is a part of the finger 20 (referred to as one surface or the first surface) and is located on the back side of the finger pulp is defined as the back (dorsal surface) of the finger 20. The Z-axis direction is the direction from the finger pulp of the finger 20 toward the back. The back (dorsal surface) of the finger 20 is a surface that does not contact the object 2.

[0053] It should be noted that the finger pad (ventral surface) and the dorsal surface (dorsal surface) of the finger 20 may be composed of a pair of surfaces that can be clearly distinguished from each other (for example, a pair of parallel planes when the finger 20 has a rectangular parallelepiped shape). In addition, the finger pad (ventral surface) and the dorsal surface (dorsal surface) of the finger 20 may also be composed of a part and another part of a surface that cannot be clearly distinguished from each other (for example, a cylindrical surface when the finger 20 has a cylindrical shape).

[0054] The extension directions of the first finger 201 and the second finger 202 in the initial state are the same. The bending directions of the first finger 201 and the second finger 202 are different. Therefore, between the X1Y1Z1 coordinate system as the orthogonal coordinate system related to the first finger 201 and the X2Y2Z2 coordinate system as the orthogonal coordinate system related to the second finger 202, the following relationship holds. That is, the X1 axis and the X2 axis are parallel to each other, and the direction of the X1 axis and the direction of the X2 axis are in the same direction. In addition, the Y1 axis and the Y2 axis are parallel to each other, and the direction of the Y1 axis and the direction of the Y2 axis are in opposite directions to each other. In addition, the Z1 axis and the Z2 axis are parallel to each other, and the direction of the Z1 axis and the direction of the Z2 axis are in opposite directions to each other.

[0055] It should be noted that, in the present embodiment, as shown in FIG. 1 , in the initial state, the extension directions of the first finger 201 and the second finger 202 are the same, but the extension directions of the first finger 201 and the second finger 202 in the initial state may be different. For example, the first finger 201 and the second finger 202 may be arranged in a manner of extending in opposite directions (radially when the number of fingers 20 is 3 or more) relative to each other. In this case, the following relationship holds between the X1Y1Z1 coordinate system as an orthogonal coordinate system associated with the first finger 201 and the X2Y2Z2 coordinate system as an orthogonal coordinate system associated with the second finger 202. That is, the X1 axis and the X2 axis are parallel to each other, and the direction of the X1 axis and the direction of the X2 axis are opposite to each other. In addition, the Y1 axis and the Y2 axis are parallel to each other, and the direction of the Y1 axis and the direction of the Y2 axis are opposite to each other. In addition, the Z1 axis and the Z2 axis are parallel to each other, and the direction of the Z1 axis and the direction of the Z2 axis are the same direction.

[0056] The finger 20 is configured to bend when the pressure of the fluid inside the finger 20 increases, and to return to its original shape when the pressure of the fluid decreases. The finger 20 is configured so that the degree of bending of the finger 20 changes depending on the pressure of the fluid inside the finger 20. Therefore, when the fluid pressure applying device applies pressure to the fluid in the pipeline, the pressure is transmitted to the fluid inside the finger 20 via the base 10, and the finger 20 bends, for example, as shown in FIG. 2. Therefore, the robot hand 1 can grasp the object 2.

[0057] The robot hand 1 can be mounted on a robot arm. After grasping the object 2, the robot arm is operated to move the robot hand 1, whereby the robot hand 1 can lift the object 2 or move the object 2 to a destination.

[0058] (Structure of fingers)

[0059] Next, the finger 20 will be described in detail. The finger 20 is composed of a sheath 30 and a plurality of blocks 40 (see FIG. 10 ). The outer surface portion of the finger 20 is composed of the sheath 30. Therefore, the sheath 30 will be described first.

[0060] (Sheath)

[0061] Fig. 3 is a front view of the sheath 30, and Fig. 4 is a side view of the sheath 30. Fig. 5 is a VV cross-sectional view in Fig. 3, Fig. 6 is a VI-VI cross-sectional view in Fig. 4, and Fig. 7 is a VII-VII cross-sectional view in Fig. 4.

[0062] The sheath 30 is formed of a resin having flexibility and elasticity. The sheath 30 can be formed of a material having a Shore A hardness of 10 to 90. The material forming the sheath 30 can be, for example, polyurethane rubber, silicone rubber, and olefin-based thermoplastic elastomer.

[0063] As described above, the sheath 30 constitutes the outer surface portion of the finger 20. Therefore, a portion of the sheath 30 constitutes the finger pulp of the finger 20, and another portion of the sheath 30 constitutes the back of the finger 20. In other words, the finger pulp of the sheath 30 constitutes the finger pulp of the finger 20, and the back of the finger of the sheath 30 constitutes the back of the finger 20. That is, the finger pulp of the sheath 30 is the finger pulp of the finger 20, and the back of the finger of the sheath 30 is the back of the finger 20. In addition, the base end of the sheath 30 is the base end of the finger 20, and the front end of the sheath 30 is the front end of the finger 20.

[0064] As shown in Fig. 3, when viewed from the front (viewed from the YZ plane), the sheath 30 has a shape (D-shape) formed by combining an arc along the edge of the back of the finger and a straight line along the edge of the finger pulp. It should be noted that the sheath 30 may also have a polygonal shape such as a quadrilateral or a triangle, or a circle when viewed from the front.

[0065] In addition, as can be seen clearly in a side view (observed in a manner facing the XZ plane), that is, as shown in FIG. 4 , the sheath 30 includes a plurality of convex portions 31 and a plurality of concave portions 32. The plurality of convex portions 31 and the plurality of concave portions 32 are arranged so as to be alternately arranged along the direction in which the sheath 30, i.e., the finger 20, extends (i.e., the X-axis direction). The convex portion 31 constituting the base end (the portion connected to the base 10) of the sheath 30 constitutes a proximal end portion 33. In addition, the convex portion 31 constituting the front end (the portion farthest from the base 10) of the sheath 30 constitutes a distal end portion 34.

[0066] The convex part 31 has a shape protruding in the direction from the finger web to the finger back (ie, the Z-axis direction) of the sheath 30 . The concave part 32 has a shape concave in the direction from the finger back to the finger web of the sheath 30 .

[0067] As shown in FIG5 , a cavity 35 as a space is formed inside the convex portion 31 including the proximal end portion 33 and the distal end portion 34. That is, the sheath 30 includes a plurality of cavities 35. Each cavity 35 has the same shape as each other. In the present embodiment, as shown in FIG6 , the cavity 35 has a shape (D-shaped) formed by combining an arc located on the back side of the finger and a straight line located on the web side of the finger when viewed from the front. In addition, as shown in FIG5 , the cavity 35 has a shape formed by rounding the corners of a rectangle when viewed from the side.

[0068] In addition, the sheath 30 is provided with a connection portion 36 that connects adjacent convex portions 31 to each other at a position that is parallel to the concave portion 32 along the Z-axis direction and closer to the fingertip of the sheath 30 than the concave portion 32. A passage 37 extending along the X-axis direction is formed in the connection portion 36. The passage 37 connects a chamber 35 with another chamber 35. That is, the chambers 35 adjacent to each other among the plurality of chambers 35 are connected to each other through the passage 37. In the present embodiment, as shown in FIGS. 6 and 7, the chambers 35 adjacent to each other are connected to each other through a pair of passages 37 parallel to each other along the Y-axis direction. It should be noted that the chambers 35 adjacent to each other may be connected to each other through one passage 37 instead of a pair of passages 37, or may be connected to each other through three or more passages 37.

[0069] The chamber 35 formed in the proximal end portion 33 communicates with the outside of the sheath 30 via the proximal end passage 38. The proximal end passage 38 is an entrance and exit of the internal space of the sheath 30 composed of a plurality of chambers 35 and passages 37 communicating therewith. Each passage 37 and the proximal end passage 38 are arranged in a manner arranged on one or more (two in this embodiment) lines (straight lines in this embodiment).

[0070] Each recess 32 is disposed between adjacent cavities 35 among the plurality of cavities 35, and is deeply recessed to the extent that the bottom of the recess 32 approaches the passage 37. When the back of the finger of the sheath 30 is cut along a plane parallel to the XZ plane, it presents a cross-sectional surface extending in a zigzag shape. On the other hand, when the finger web of the sheath 30 is cut along a plane parallel to the XZ plane, it presents a cross-sectional surface extending in a straight line. That is, the back of the finger of the sheath 30 is in an accordion shape, and the finger web side is in a flat plate shape. In other words, the stroke along the back of the finger of the sheath 30 from the base end to the front end is longer than the stroke along the finger web of the sheath 30. In other words, the sheath 30 has a recess 32 on the first surface (i.e., the back surface) of the outer surface of the sheath 30 that does not contact the object grasped by the robot hand 1. Furthermore, the sheath 30 has a flat surface on a second surface (ie, ventral surface) of the outer surface of the sheath 30 that is opposite to the first surface (ie, rear surface) and that can contact an object grasped by the robot hand.

[0071] (Block)

[0072] Next, the block body 40 disposed in the sheath 30 will be described. FIG8 is a front view of the block body 40, and FIG9 is a side view of the block body 40. FIG.

[0073] The block 40 is a member disposed in the chamber 35 of the sheath 30. The block 40 is formed of a rigid material that does not deform even when the pressure of the fluid in the sheath 30 changes, and does not deform even when an external force is applied to the finger 20 or the finger 20 applies a gripping force to the object 2. The block 40 is formed of a material that is not bonded to the sheath 30, such as silicone resin.

[0074] The block 40 includes a cylindrical peripheral surface 41, a flat bottom surface 42, a flat distal end surface 43, and a flat proximal end surface 44. The distal end surface 43 and the proximal end surface 44 are parallel to each other. In addition, the peripheral surface 41 and the bottom surface 42 are orthogonal to the distal end surface 43 and the proximal end surface 44.

[0075] The block 40 has the same shape as the cavity 35 when the finger 20 is in the initial state. That is, in the present embodiment, the block 40 has a shape formed by combining an arc located on the back side of the finger and a straight line located on the web side of the finger when viewed from the front, and has a shape formed by rounding the corners of a rectangle when viewed from the side. The block 40 may have a shape formed by cutting a portion of a cylinder from a cylinder along a plane parallel to the central axis of the cylinder.

[0076] The block 40 includes a through hole 45 . The through hole 45 opens at the distal end surface 43 and the proximal end surface 44 .

[0077] In the present embodiment, the block 40 has a pair of through holes 45. The number of through holes 45 provided in the block 40 is equal to the number of passages 37 connecting mutually adjacent chambers 35. Therefore, when mutually adjacent chambers 35 are connected to each other through one passage 37, the block 40 has one through hole 45. In addition, when mutually adjacent chambers 35 are connected to each other through three or more passages 37, the block 40 has three or more through holes 45.

[0078] When the block 40 is arranged in the cavity 35 of the sheath 30, the through hole 45 is arranged at a position overlapping with the passage 37 in front view. The shape of the through hole 45 in front view is the same as the shape of the passage 37 in front view.

[0079] (finger)

[0080] Next, the finger 20 composed of the sheath 30 and the block 40 will be described. Fig. 10 is a VV cross-sectional view of the case where the sheath 30 shown in Fig. 3 is the finger 20 (that is, the block 40 is arranged in the sheath 30). In Fig. 10, the part indicated by the reference numeral 21 is the back of the finger 20, and the part indicated by the reference numeral 22 is the web of the finger 20.

[0081] One block 40 is disposed in each of the plurality of chambers 35 of the sheath 30. The through hole 45 provided in the block 40 is disposed so as to be connected to the passage 37. The proximal passage 38, the plurality of passages 37 and the plurality of through holes 45 constitute a linearly extending long hole with one end closed in the initial state.

[0082] The inner surface of the chamber 35 is easily separated from the outer surface of the block 40 (specifically, the peripheral surface 41, the bottom surface 42, the distal end surface 43, and the proximal end surface 44). A thin gap may exist between the inner surface of the chamber 35 and at least a portion of the outer surface of the block 40 (e.g., the peripheral surface 41, the distal end surface 43, and the proximal end surface 44).

[0083] When pressure is applied to the fluid in the finger 20 configured as described above from the pressure applying device via the base 10, the pressure of the fluid in the finger 20 increases. Specifically, the pressure of the fluid in the cavity 35 and the passage 37 increases.

[0084] Then, the sheath 30 expands. At this time, each part of the sheath 30 stretches. When the thickness of each part constituting the sheath 30 is the same, the stretch amount per unit length of each part is equal. In addition, the stroke along the back of the finger (back 21) of the sheath 30 from the base end to the front end is longer than the stroke along the web of the finger (web 22) of the sheath 30. Therefore, the total stretch amount of the back 21 is longer than the total stretch amount of the web 22.

[0085] As a result, as shown in FIG11 , the finger 20 is bent and deformed along the XZ plane with the back 21 located on the outer periphery and the abdomen 22 located on the inner periphery. At this time, the finger 20 is in the working state. When the pressure of the fluid in the finger 20 is restored, that is, reduced, the finger 20 returns to the state shown in FIG10 , that is, the initial state. By adjusting the pressure of the fluid in the finger 20, the difference between the elongation of the back 21 and the elongation of the abdomen 22 can be adjusted, and the degree of bending of the finger 20 can be adjusted. That is, the finger 20 can be made into a desired shape.

[0086] It should be noted that, when the thickness of each part constituting the sheath 30 is different depending on the part, the amount of elongation per unit length of each part is different depending on the part. Specifically, the elongation of a thick part is smaller than that of a thin part. Therefore, by setting the thickness of each part constituting the sheath 30 to a different thickness depending on the part, for example, by making the abdomen 22 thicker than the back 21, the degree of bending of the finger 20 can be adjusted.

[0087] When the sheath 30 expands, adjacent convex portions 31 may contact each other. By making the convex portions 31 contact each other and being pressed against each other, the bending degree of the finger 20 can be increased, the gripping force of the robot hand 1 can be increased, or the shape retention can be improved.

[0088] (Effect)

[0089] The robot hand 1 configured as described above includes at least one finger 20. The finger 20 includes a sheath 30 including a plurality of chambers 35, passages 37 for connecting adjacent chambers 35 among the plurality of chambers 35, and recesses 32 disposed between adjacent chambers 35 among the plurality of chambers 35. In addition, the finger 20 includes a plurality of blocks 40 disposed in the plurality of chambers 35.

[0090] As a result, the fingers 20 included in the robot hand 1 can assume a desired shape. Furthermore, the robot hand 1 can reliably grasp the object 2 .

[0091] In addition, assuming that the block 40 is not disposed in the chamber 35, when an external force such as a force parallel to the X-axis direction and compressing the finger 20 is applied to the front end of the finger 20, the chamber 35 may be deformed in a flattened manner. If each chamber 35 is flattened, the deformation amount (contraction amount) of the finger 20 becomes larger. In this state, if the pressure of the fluid in the finger 20 increases, the finger 20 may be deformed unexpectedly. In other words, the possibility of not being able to grasp the object 2 becomes higher. It should be noted that this situation may occur, for example, when the finger 20 is inserted into a container in order to grasp one object 2 from a plurality of objects 2 placed in the container, and the finger 20 contacts an object 2 that is not the object to be grasped.

[0092] On the other hand, the block 40 is disposed in the cavity 35. Therefore, even if an external force is applied to the finger 20, the cavity 35 does not deform, and can maintain the shape before the external force is applied to the finger 20. As a result, the finger 20 as a whole can maintain the shape before the external force is applied to the finger 20. Therefore, before the robot hand 1 grasps the object 2 or when grasping the object 2, it is possible to prevent the finger 20 from being deformed unexpectedly due to the external force. Furthermore, the finger 20 can be made into a desired shape, so that the object 2 can be grasped reliably.

[0093] In the present embodiment, each of the plurality of blocks 40 has an outer surface shape that is the same as the inner surface shape of one of the plurality of chambers 35 that contain the blocks 40. That is, in the initial state, there is no gap between the inner surface of the chamber 35 and the outer surface of the block 40, or the gap between the inner surface of the chamber 35 and the outer surface of the block 40 is very small. Therefore, the finger 20 will not be deformed due to the change in the size of the gap between the chamber 35 and the block 40 caused by the external force. Thus, before the robot hand 1 grasps the object 2, it is possible to reliably prevent the finger 20 from being deformed unexpectedly due to the external force.

[0094] It should be noted that the plurality of blocks 40 may not all be of the same shape (i.e., of the same size and similar shape). For example, the blocks 40 may become smaller as they move from the base end of the finger 20 to the front end. In the above case, the chamber 35 may also become smaller as they move from the base end of the finger 20 to the front end.

[0095] In addition, in the present embodiment, each of the plurality of blocks 40 has a pair of planes (i.e., a distal end face 43 and a proximal end face 44) that are orthogonal to the direction in which the passage 37 extends. In other words, the blocks 40 are arranged in the chamber 35 in such a manner that the direction in which the passage 37 extends is orthogonal to the distal end face 43 and the proximal end face 44. By such an arrangement, the distal end face 43 of one block 40 is parallel to the proximal end face 44 of the other block 40 via the recess 32 and the connecting portion 36. Thus, even if an external force that is parallel to the X-axis direction and compresses the finger 20 is applied to the front end of the finger 20, the finger 20 is only minimally deformed. Specifically, after the finger 20 is slightly bent in such a manner that the back 21 becomes the inner peripheral side and the abdomen 22 becomes the outer peripheral side, it will not be further deformed. That is, after the finger 20 is slightly deformed in such a manner that one block 40 and the other blocks 40 are pressed against each other via the recess 32, the finger 20 will not be further deformed. Therefore, even in a state where an external force is applied, the finger 20 can be made into a desired shape, and the object 2 can be grasped reliably.

[0096] In addition, in this embodiment, similarly to the block 40, the convex portion 31 also has a pair of wall surfaces that are orthogonal to each other along the direction in which the passage 37 extends. Thus, by increasing the pressure of the fluid in the sheath 30 to expand the sheath 30, the wall surfaces of the convex portions 31 disposed adjacent to each other can be easily brought into contact with each other. In other words, the convex portions 31 can be easily brought into a state of being pressed against each other. Therefore, the degree of bending of the finger 20 can be increased, the gripping force of the robot hand 1 can be increased, or the shape retention can be improved.

[0097] Furthermore, in the present embodiment, the block 40 is disposed in the chamber 35 and does not enter the passage 37. Furthermore, the blocks 40 are disposed in the sheath 30 in a manner that they do not directly contact each other. In other words, the convex portion 31 of the chamber 35 in which the block 40 is disposed is connected to the adjacent convex portion 31 via the connecting portion 36 formed with the passage 37. Thus, when the finger 20 is deformed, the blocks 40 are in contact with each other, thereby preventing the deformation of the finger 20 from being hindered. Therefore, the finger 20 can be made into the desired shape, thereby reliably holding the object 2. Furthermore, the blocks 40 are in contact with each other, thereby preventing the generation of noise.

[0098] In addition, in the present embodiment, each of the plurality of blocks 40 includes a through hole 45 connected to the passage 37. Thus, the pressure applied by the pressure applying device is smoothly transmitted to the finger 20. That is, the pressure in each chamber 35 can be quickly made the same. Thus, the finger 20 can be made into a desired shape, and the object 2 can be gripped reliably.

[0099] It should be noted that the block 40 may not have the through hole 45. In this case, the pressure applied by the pressure applying device can be transmitted to the finger 20 through the gap between the inner surface of the chamber 35 and the outer surface of the block 40 and the passage 37. As a result, the finger 20 can be bent.

[0100] In addition, in the present embodiment, the block 40 has a bottom surface 42 which is a plane, and a part of the inner surface of the chamber 35 is constituted by a plane opposite to the bottom surface 42. Thus, the block 40 does not rotate around an axis parallel to the X-axis (e.g., the center axis of the finger 20) in the chamber 35. That is, a plurality of blocks 40 are respectively arranged in a plurality of chambers 35 in a state of being stopped. Therefore, even if the pressure in the chamber 35 increases and the gap between the inner surface of the chamber 35 and the outer surface of the block 40 increases, the through hole 45 can reliably maintain a state of being arranged in a line together with the passage 37 and the proximal end passage 38. Furthermore, regardless of the pressure of the fluid in the finger 20 and the degree of bending of the finger 20, the pressure in each chamber 35 can be quickly made the same pressure.

[0101] It should be noted that, needless to say, the method of stopping the block 40 in the plurality of chambers 35 is not limited to the block 40 having a flat bottom surface 42 and a portion of the inner surface of the chamber 35 being composed of a flat surface opposite to the bottom surface 42. For example, the block 40 may have a tenon and the chamber 35 may have a tenon groove into which the tenon is inserted.

[0102] Furthermore, in the present embodiment, the plurality of blocks 40 may have outer surfaces formed with wrinkles. Specifically, wrinkles may be formed on at least one of the peripheral surface 41, the bottom surface 42, the distal surface 43, and the proximal surface 44. Wrinkles may also be formed on all of the peripheral surface 41, the bottom surface 42, the distal surface 43, and the proximal surface 44. By forming wrinkles on the outer surface of the block 40, when the pressure of the fluid in the sheath 30 increases and the sheath 30 expands, the outer surface of the block 40 can be quickly separated from the inner surface of the chamber 35. Furthermore, the finger 20 can be deformed smoothly. As a result, the finger 20 can be made into the desired shape, thereby reliably holding the object 2.

[0103] In addition, in the present embodiment, the sheath 30 can be formed of a material having a Shore A hardness of 10 or more and 90 or less. In the above case, the sheath 30 has flexibility and elasticity. Therefore, the sheath 30, that is, the finger 20 can be deformed smoothly following the change in the pressure of the fluid in the sheath 30. Furthermore, the finger 20 can be made into a desired shape, so that the object 2 can be gripped reliably.

[0104] The sheath 30 may be formed of a material having a Shore A hardness of 30 or more and 70 or less. In this case, the sheath 30 can more reliably have the flexibility and stretchability required for deforming and grasping the object 2 .

[0105] Furthermore, the passage 37 may be formed at a position closer to the fingertips of the sheath 30 than the center of the chamber 35 along the direction from the fingertips of the sheath 30 toward the back of the finger (i.e., the Z-axis direction). By forming the passage 37 at this position, the recess 32 can be deepened. Furthermore, the stroke along the back of the finger from the base end to the front end of the sheath 30 can be made longer than the stroke along the fingertips of the sheath 30. Therefore, the finger 20 can be reliably deformed in a manner such that the back 21 is located on the outer periphery and the belly 22 is located on the inner periphery along the XZ plane.

[0106] (Manufacturing method)

[0107] Next, a method for manufacturing the robot hand 1 will be described. First, a method for manufacturing the finger 20 will be described with reference to Fig. 12 to Fig. 15. The XYZ coordinate system shown in Fig. 12 to Fig. 15 represents the XYZ coordinate system of the manufactured finger.

[0108] FIG. 12 is a cross-sectional view of an article prepared when manufacturing the finger 20. The symbol 50 in FIG. 12 represents a mold. The mold 50 is, for example, a metal mold. The mold 50 includes an upper mold 51 and a lower mold 52. The lower mold 52 includes a plurality of protrusions 53. The member marked with the symbol 54 in FIG. 12 is a rod. The rod 54 passes through a plurality of blocks 40. That is, the rod 54 is inserted into the through hole 45 of the block 40. It should be noted that only one rod 54 is shown in FIG. 12, but a pair of rods 54 are arranged in an overlapping manner along the Y-axis direction and pass through a plurality of blocks 40. The rod 54 is a round rod extending linearly.

[0109] Next, as shown in FIG. 13 , the plurality of blocks 40 in a state where the rod 54 penetrates are arranged between the upper mold 51 and the lower mold 52 in an alternating arrangement with the plurality of protrusions 53, and the upper mold 51 is joined to the lower mold 52. In other words, the plurality of blocks 40 are arranged in the mold 50 in a state where the plurality of blocks 40 and the plurality of protrusions 53 are arranged alternately. At this time, a cavity 55 is formed between the upper mold 51 and the lower mold 52. A portion of the rod 54 and the plurality of blocks 40 are located in the cavity 55.

[0110] Next, as shown in FIG14 , a liquid resin 60 is injected into the mold 50, that is, into the mold cavity 55, and the plurality of blocks 40 are wrapped with the resin 60. When the resin 60 is a thermosetting resin, the resin 60 is heated. In addition, when the resin 60 is a thermoplastic resin, the resin 60 is cooled. In either case, the resin 60 is solidified in the mold 50 to form a sheath 30 having flexibility and elasticity. It should be noted that, although not shown in the cross-sectional view shown in FIG14 , a supply port for injecting the liquid resin 60 and an exhaust port are formed in at least one of the upper mold 51 and the lower mold 52.

[0111] The block 40 functions as a mold for forming the cavity 35 , and the rod 54 functions as a mold for forming the passage 37 and the proximal end passage 38 .

[0112] Next, the sheath 30 and the plurality of blocks 40 are taken out of the mold 50 together with the rod 54. FIG. 15 shows the rod 54, the sheath 30, and the plurality of blocks 40 taken out of the mold 50. Then, the rod 54 is pulled out from the plurality of blocks 40 while the plurality of blocks 40 remain in the cured resin 60 (i.e., the sheath 30). That is, only the rod 54 is pulled out from the sheath 30. Thus, the finger 20 shown in FIG. 10 is manufactured. It should be noted that the rod 54 may be pulled out from the sheath 30 while the sheath 30 and the plurality of blocks 40 are in the mold 50.

[0113] After the finger 20 is manufactured, the finger 20 is attached to the base 10 , thereby completing the robot hand 1 .

[0114] (Effect)

[0115] According to the manufacturing method described above, the sheath 30 is formed by solidifying the liquid resin 60 in the mold 50. Thus, the sheath 30 is completely formed in one piece. That is, the sheath 30 has no gaps through which the fluid leaks, and also has no bonding portions that may become gaps. Therefore, after the robot hand 1 is manufactured, even if the pressure of the fluid in the sheath 30 is increased, the fluid can be prevented from leaking out of the sheath 30. Furthermore, the finger 20 can be formed into a desired shape.

[0116] It should be noted that the sheath 30 may be formed by a 3D printer of a fused deposition modeling method by wrapping a plurality of blocks 40 in a state where the rods 54 are inserted with a resin layer. However, when the sheath 30 is formed by a 3D printer of a fused deposition modeling method, there is a possibility that the fluid leaks from the gaps between the deposited layers. However, as described above, by solidifying the liquid resin 60 in the mold 50 to form the sheath 30, the sheath 30 can be formed completely in one piece, thereby reliably preventing the fluid from leaking from the gaps, etc.

[0117] Furthermore, according to the manufacturing method, the block 40 that functions as a mold when forming the sheath 30, especially the cavity 35, can remain in the sheath 30 after the sheath 30 is manufactured. That is, the block 40 that forms the inner surface of the sheath 30 does not need to be extracted from the sheath 30.

[0118] This can prevent the sheath 30 from being damaged by the mold being pulled out from the sheath 30 , thereby improving the yield rate when manufacturing the robot hand 1 .

[0119] Furthermore, since it is not necessary to extract the block 40, the cross-sectional area of ​​the chamber 35 (the cross-sectional area when cut by a plane parallel to the YZ plane) can be sufficiently increased relative to the cross-sectional area of ​​the passage 37 (the cross-sectional area when cut by a plane parallel to the YZ plane). As a result, the recess 32 can be deepened. Furthermore, the stroke along the back of the finger from the base end to the front end of the sheath 30 can be made longer than the stroke along the finger pulp of the sheath 30 more reliably. Therefore, the finger 20 can be reliably deformed in a manner such that the back 21 is located on the outer periphery and the belly 22 is located on the inner periphery along the XZ plane.

[0120] In the above manufacturing method, the mold 50 is arranged so that the convex portion 53 formed on the lower mold 52 is in a posture of protruding from the bottom to the top. As a result, when the liquid resin 60 is injected into the cavity 55, it is possible to prevent air from being left between the convex portions 53 without being exhausted. Furthermore, the thickness of each part of the sheath 30 can be made to be the designed thickness. As a result, the finger 20 can be reliably made into the expected shape by adjusting the pressure of the fluid in the sheath 30.

[0121] It should be noted that the cavity 55 may be made evacuated in advance. In addition, exhaust ports may be formed in the regions between the protrusions 53. In these cases, the mold 50 may not be configured in such a manner that the protrusions 53 formed on the lower mold 52 are in a posture protruding from the bottom to the top. For example, the mold 50 may be configured in such a manner that the protrusions 53 are in a posture protruding from the top to the bottom. That is, the upper mold 51 and the lower mold 52 may be configured in such a manner that the lower mold 52 is located above the upper mold 51. In addition, the mold 50 may be configured in such a manner that the protrusions 53 are in a posture protruding in the horizontal direction. That is, the upper mold 51 and the lower mold 52 may be configured in such a manner that they are at the same height.

[0122] In the above manufacturing method, the rod 54 is sandwiched between the upper mold 51 and the lower mold 52. In addition, the rod 54 is cantilevered in the mold cavity 55. Thus, the space in the sheath 30 and the outside of the sheath 30 can be communicated only through the proximal end passage 38 where the rod 54 is molded.

[0123] It should be noted that, when the sheath 30 forms an opening other than the proximal end passage 38, a process of blocking the opening is required. In addition, even if blocked, the possibility of fluid leaking from the blocked opening is relatively high compared to a case where there is no such opening. However, the sheath 30 manufactured by the above-mentioned manufacturing method originally has no opening other than the proximal end passage 38. Therefore, a process of blocking the opening is not required, and leakage of the fluid from the sheath 30 can be prevented in advance.

[0124] In the above manufacturing method, the plurality of blocks 40 are in a state of not contacting the inner surface of the mold 50. In other words, a gap of a predetermined thickness is formed between the outer surface of the block 40 and the inner surface of the mold 50. The thickness of the gap corresponds to the thickness of the sheath 30. That is, by making the plurality of blocks 40 not contact the inner surface of the mold 50, it is possible to prevent the sheath 30 from having a portion of zero thickness, that is, it is possible to prevent the sheath 30 from having a hole.

[0125] In the above manufacturing method, a pair of rods 54 penetrates through the plurality of blocks 40, and the pair of rods 54 are sandwiched between the upper mold 51 and the lower mold 52. As a result, each rod 54 cannot rotate relative to the mold 50 or the plurality of blocks 40. That is, the plurality of blocks 40 cannot rotate relative to the mold 50. Therefore, when the block 40 in the state of being penetrated by the rod 54 is arranged in the mold 50, if the block 40 and the mold 50 are set to be in a state of non-contact, the block 40 will not rotate in the cavity 55 and cause the block 40 to contact the mold 50. For example, even if the block 40 is squeezed by the resin 60 when the molten resin 60 is injected into the cavity 55, the block 40 will not contact the mold 50. That is, by arranging the rod 54 in the mold 50 in a state of being stopped relative to the mold 50 and the plurality of blocks 40, it is possible to reliably prevent the block 40 from contacting the mold 50 and forming the sheath 30 with holes.

[0126] In addition, in the above manufacturing method, after the resin 60 is cured, a fluid may be supplied to the cured resin 60 (i.e., the sheath 30) to expand the cured resin 60, thereby peeling the block 40 from the inner surface of the cured resin 60. If such a process is performed, when the pressure applying device applies pressure to the fluid in the sheath 30 in order to actually use the robot hand 1, the outer surface of the block 40 can be reliably separated from the inner surface of the chamber 35. Furthermore, the finger 20 can be reliably deformed. As a result, the finger 20 can be made into a desired shape, so that the object 2 can be reliably grasped.

[0127] (Variation)

[0128] The robot hand and the method for manufacturing the robot hand disclosed in the present invention are not limited to the specific embodiments described above, but include embodiments in which various modifications are made without departing from the gist of the invention.

[0129] For example, the robot hand 1 may not include the base 10. That is, the robot hand 1 may be composed of only one or more fingers 20. For example, the robot hand 1 may be composed of only one finger 20. In this case, the robot hand 1 can bend the finger 20 to hang a soft and long object on the finger 20 and grasp it.

[0130] When the pressure of the fluid in the finger 20 is equal to the pressure of the fluid outside the finger 20 (e.g., atmospheric pressure), the finger 20 may have a shape other than a straight shape, for example, a shape along an arc. In this case, each passage 37 and the proximal end passage 38 are arranged in a manner arranged on an arc-shaped curve. In this case, the finger pad of the finger 20 may be located on the inner circumference of the arc or on the outer circumference. When the finger pad is located on the inner circumference of the arc and the back of the finger is located on the outer circumference of the arc, the pressure of the fluid may be increased to deform the finger 20 in a manner that the degree of bending becomes larger, thereby causing the robot hand 1 to grasp the object. In addition, when the finger pad is located on the outer circumference of the arc and the back of the finger is located on the inner circumference of the arc, the pressure of the fluid may be increased to deform the finger in a manner that the degree of bending becomes smaller (e.g., to make it straight) or to bend to the opposite side, thereby causing the robot hand 1 to grasp the object. The finger 20 having a shape along an arc may be manufactured by using a round rod extending along the arc as the rod 54.

[0131] The disclosed contents of the specification, drawings and abstract contained in the Japanese application No. 2022-104716 filed on June 29, 2022 are incorporated herein by reference in their entirety.

[0132] Industrial Applicability

[0133] The present disclosure can be utilized as a robot hand that grasps various objects and a method for manufacturing the same.

[0134] Explanation of symbols

[0135] 1: robot hand, 2: object, 3: placement surface, 10: base, 11: port, 20: finger, 201: first finger, 202: second finger, 21: back, 22: abdomen, 30: sheath, 31: convex portion, 32: concave portion, 33: proximal end portion, 34: distal end portion, 35: chamber, 36: connecting portion, 37: passage, 38: proximal end passage, 40: block, 41: peripheral surface, 42: bottom surface, 43: distal end surface, 44: proximal end surface, 45: through hole, 50: mold, 51: upper mold, 52: lower mold, 53: convex portion, 54: rod, 55: mold cavity, 60: resin.

Claims

1. A robot hand is a robot hand having at least one finger, The finger has: a sheath having a plurality of chambers, a passage connecting adjacent chambers among the plurality of chambers, and a recessed portion disposed between adjacent chambers among the plurality of chambers; and A plurality of blocks are disposed in the plurality of chambers.

2. The robot hand according to claim 1, wherein: Each of the plurality of blocks includes a through hole connected to the passage.

3. The robot hand according to claim 2, wherein: The plurality of blocks are respectively arranged in the plurality of chambers in a state where they are prevented from rotating.

4. The robot hand according to claim 1, wherein: Each of the plurality of blocks has an outer surface shape that is the same as an inner surface shape of one of the plurality of chambers that accommodates the block.

5. The robot hand according to claim 1, wherein: The plurality of blocks have outer surfaces formed with corrugations.

6. The robot hand according to claim 1, wherein: The sheath is formed of a material having a Shore A hardness of 10 or more and 90 or less.

7. The robot hand according to claim 1, wherein: Each of the plurality of blocks has a pair of planes that are orthogonal to a direction in which the passage extends.

8. The robot hand according to claim 1, wherein: The sheath has the recessed portion on a first surface of the outer surface of the sheath that is not in contact with an object grasped by the robot hand. The sheath has a flat surface on a second surface of the outer surface of the sheath that is opposite to the first surface and can come into contact with the object.

9. The robot hand according to claim 1, wherein: The material forming the sheath is polyurethane rubber, silicone rubber, or olefin-based thermoplastic elastomer. The material forming the block is silicone resin.

10. A method for manufacturing a robot hand, comprising: Prepare a plurality of blocks through which rods are inserted and a mold having a plurality of convex portions on the inner surface, The plurality of blocks are arranged in the mold in a state where the plurality of blocks and the plurality of protrusions are arranged alternately. injecting liquid resin into the mold to wrap the plurality of blocks with the resin, curing the resin, The plurality of blocks are left in the cured resin, and the rod is extracted from the plurality of blocks.

11. The method for manufacturing a robot hand according to claim 10, further comprising: The mold is arranged so that the plurality of projections are in a posture of projecting upward from the bottom.

12. The method for manufacturing a robot hand according to claim 10, wherein: The plurality of blocks are arranged in the mold in a state of not contacting the inner surface.

13. The method for manufacturing a robot hand according to claim 12, wherein: The rod is arranged in the mold in a state where it is prevented from rotating relative to the mold and the plurality of blocks.

14. The method for manufacturing a robot hand according to claim 10, further comprising: supplying a fluid into the solidified resin to expand the solidified resin, The block is peeled off from the inner surface of the cured resin.

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