Gripping mechanism

Abstract

To provide a gripping mechanism that can be thinned.SOLUTION: A gripping mechanism grips a component. The gripping mechanism comprises a first member having a concave surface in a shape in which a portion of a spherical surface or a conical surface is cut off annularly, and a second member arranged to oppose to the first member, which has a convex part which moves along the concave surface while contacting the concave surface of the first member. The gripping mechanism has a connecting mechanism that connects the first member to the second member and has a spring that energizes either of the first member and the second member toward the other. The gripping mechanism allows the second member to incline with respect to the first member by deflection of the spring.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gripping mechanism. [Background technology]

[0002] Patent Document 1 discloses a gripping device. In this gripping device, a support shaft on the side of a holder fixed to a robot is formed in a bowl shape. A declination absorbing member facing the support shaft has a spherical surface facing the inner surface of the bowl-shaped support shaft, and the declination absorbing member is rotatable around the holder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 136391 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned gripping device has a bowl-shaped support shaft, and therefore the axial dimension of the support shaft is large, which poses a problem of increasing the thickness of the device.

[0005] The present invention has been made in consideration of the above problems, and has an object to make it possible to reduce the thickness of a gripping device. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a gripping mechanism for gripping a part, comprising: a first member having a concave surface formed by cutting out a portion of a spherical or conical surface into a circular shape; a second member arranged opposite the first member and having a convex portion that moves along the concave surface of the first member while in contact with the concave surface; and a connecting mechanism that connects the first member and the second member and has a spring that biases one of the first member and the second member toward the other, wherein bending of the spring allows the second member to be inclined relative to the first member. Effect of the Invention

[0007] According to a gripping mechanism of one aspect of the present invention, the concave surface of the first member with which the convex portion of the second member moves while coming into contact has a shape obtained by cutting out a portion of a spherical or conical surface into an annular shape.

[0008] For this reason, the gripping mechanism can be made thinner than a mechanism in which a bowl-shaped support shaft is provided on a first member and a spherical portion is formed on a second member that faces the inner surface of the bowl-shaped support shaft. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view showing a gripping mechanism according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a main part of the gripping mechanism. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an explanatory diagram showing a clamping screw used in the gripping mechanism. [Diagram 5] FIG. 5 is an enlarged partial cross-sectional view of a main part of the gripping mechanism. [Figure 6] FIG. 6 is a cross-sectional view showing a main part of a gripping mechanism according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a gripping mechanism 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a side view showing the gripping mechanism 10 according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing a main part of the gripping mechanism 10. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is an explanatory view showing a clamping screw 12 used in the gripping mechanism 10. Fig. 5 is a partial cross-sectional view showing an enlarged main part of the gripping mechanism 10.

[0011] As shown in FIG. 1, the gripping mechanism 10 is attached to the tip of a robot arm 20 of a robot (not shown), and is a mechanism for gripping a part 22.

[0012] To explain this by taking an example, the part 22 is, for example, a nut. The robot grips the nut with the gripping mechanism 10 and temporarily fastens the gripped nut to, for example, the shaft of a pulley (not shown). If the pulley shaft is tilted, the nut cannot be temporarily fastened to the shaft. For this reason, the gripping mechanism 10 allows the gripped nut to be tilted, making it possible to temporarily fasten the nut to the shaft.

[0013] The gripping mechanism 10 includes an attachment part 30 that is detachably attached to the tip of a robot arm 20. The attachment part 30 is formed in a circular ring shape. The attachment part 30 is attached to the robot arm 20 with the tip of the robot arm 20 inserted into an attachment hole 32 formed in the center of the attachment part 30.

[0014] The gripping mechanism 10 comprises a first member 40 fixed to the mounting portion 30, a second member 42 arranged opposite the first member 40, a connecting mechanism 44 (see Figure 5) that connects the first member 40 and the second member 42, and a chuck 46 provided on the second member 42.

[0015] (Chuck) The chuck 46 includes a block-shaped chuck cylinder 50 fixed to the second member 42. The chuck cylinder 50 includes an operating shaft 52 extending from one side surface 50A and the other side surface 50B. Each operating shaft 52 includes a large diameter shaft 52A and a small diameter shaft 52B having a smaller diameter than the large diameter shaft 52A. The chuck cylinder 50 is controlled by air supplied from a pipe (not shown) to set each operating shaft 52 between an extended state and a retracted state.

[0016] A support plate 60 is provided at the tip of each operating shaft 52. A gripping arm 62 is fixed to each support plate 60. Each gripping arm 62 is formed in an L-shape. The tips of both gripping arms 62 extend toward the center of the gripping mechanism 10. A claw portion 64 is provided at the tip of each gripping arm 62. Each claw portion 64 protrudes in a direction away from the chuck cylinder 50.

[0017] The gripping mechanism 10 retracts the operating shaft 52 by air supplied to the chuck cylinder 50, and operates both gripping arms 62 toward the center of the gripping mechanism 10, thereby creating a gripping state in which the part 22 is gripped by the claws 64 provided on each gripping arm 62. The gripping mechanism 10 also extends the operating shaft 52 by air supplied to the chuck cylinder 50, and operates both gripping arms 62 in directions away from each other, thereby creating a released state in which the gripped state is released.

[0018] (First member) As shown in Figs. 1 and 2, the first member 40 is formed in a rectangular plate shape. A circular opening 40A is formed in the center of the first member 40. A circular recess 70 is formed in a first opposing surface 40B of the first member 40 on the second member 42 side. The recess 70 is formed in the center of the first member 40. The center of the recess 70 is disposed on the central axis C of the attachment portion 30 formed in a circular ring shape. The central axis C of the attachment portion 30 constitutes the central axis C of the gripping mechanism 10.

[0019] The edge of the recess 70 forms a concave surface 72 that is a circular cut-out of a portion of a sphere. The concave surface 72 is formed at a position that overlaps with a spherical shape 74 that is centered on the part 22 gripped by the chuck 46 (see FIG. 1).

[0020] Specifically, the concave surface 72 is formed in a circular ring shape. The concave surface 72 is formed in a shape that retreats from the outer circumferential edge toward the mounting surface 40C to which the mounting portion 30 is attached, as it moves from the outer circumferential edge toward the inner circumferential edge.

[0021] A sphere center 76 as the center of the spherical shape 74 overlapping with the concave surface 72 (see FIG. 1) is set on the center line that becomes the rotation center of the nut when the threads of the nut as the part 22 held by the chuck 46 are aligned with the axis and temporarily fastened. Here, when the nut is temporarily fastened, the nut is rotated around the central axis C of the holding mechanism 10.

[0022] (Second member) 2 and 3, the second member 42 is formed in a rectangular plate shape. The second member 42 has a protruding portion 80 that moves along the concave surface 72 of the first member 40 while being in contact with the concave surface 72. The protruding portion 80 is composed of a plurality of clamping screws 12.

[0023] More specifically, the second member 42 has a plurality of recessed step portions 84 formed on a fixing surface 42A to which the chuck cylinder 50 is fixed. The step portions 84 are formed at eight locations equally spaced apart on a circle 86 (see FIG. 3) corresponding to the concave surface 72. A screw hole 84A is formed in each step portion 84. The screw hole 84A reaches the second opposing surface 42B opposing the first member 40.

[0024] (Clamping screw) 2 and 4, the clamping screw 12 includes a cylindrical screw body 12A and a spherical body 12B rotatably provided at the tip of the screw body 12A. The spherical body 12B protrudes from the tip of the screw body 12A and constitutes a convex portion 80 that moves along the concave surface 72 of the first member 40 while in contact with the concave surface 72. As a result, a gap 90 (see FIG. 2) is formed between the first member 40 and the second member 42.

[0025] A male screw 12C (see FIG. 4) is formed on the circumferential surface of the screw body 12A, and a hexagonal hole 12D is formed on the base end surface of the screw body 12A.

[0026] The clamping screw 12 has the screw body 12A screwed into the screw hole 84A, and the amount of screwing into the screw hole 84A is adjusted by a hexagonal wrench inserted into the hexagonal hole 12D. This adjusts the amount of protrusion of the convex portion 80 of the clamping screw 12, which is formed by a portion protruding from the second opposing surface 42B of the second member 42. The clamping screw 12 is fixed to the second member 42 by attaching a fixing nut 92 (see FIG. 2) to the base end of the screw body 12A.

[0027] In this embodiment, an example will be described in which eight clamping screws 12 are provided in the second member 42, but the number of clamping screws 12 used is not limited to this. The number of clamping screws 12 used may be, for example, three, or more than eight.

[0028] (Connection mechanism) 5, the connecting mechanism 44 includes a connecting bolt 100 that connects the first member 40 and the second member 42, and a spring 102 that biases one of the first member 40 and the second member 42 toward the other. The connecting mechanism 44 allows the second member 42 to incline relative to the first member 40 as the spring 102 flexes.

[0029] More specifically, the first member 40 has countersunk holes 104 formed at the four corners of the mounting surface 40C to which the mounting portion 30 is attached. An insertion hole 106 is formed at the bottom of the countersunk holes 104. The second member 42 has recessed steps 108 formed at the four corners of the fixing surface 42A to which the chuck cylinder 50 is fixed. The second member 42 has circular holes 110 formed at locations corresponding to the insertion holes 106 of the first member 40. The circular holes 110 open into the steps 108.

[0030] A connecting bolt 100 is inserted into each countersunk hole 104 of the first member 40. The connecting bolt 100 is, for example, a reamer bolt. A shaft portion 100A of the connecting bolt 100 is inserted through an insertion hole 106 of the first member 40 and a circular hole 110 of the second member 42. A spring 102 formed of a coil spring is attached to the shaft portion 100A. A first nut 112 and a second nut 114 are attached to the end of the shaft portion 100A.

[0031] The spring 102 is held in a compressed state between the first nut 112 and the step portion 108. The second member 42 is biased toward the first member 40 by the spring 102 while maintaining a gap 90 between the second member 42 and the first member 40. The first nut 112 is fixed by a second nut 114 after the spring force of the spring 102 is adjusted.

[0032] The spring 102 expands and contracts, so that the second member 42 and the chuck 46 fixed to the second member 42 can tilt with respect to the first member 40. In addition, when the chuck 46 tilts, the part 22 (see FIG. 1) held by the chuck 46 tilts.

[0033] (Action and Effects) The main effects of the gripping mechanism 10 configured as above will now be described.

[0034] (1) The gripping mechanism 10 is a mechanism for gripping a part 22. The gripping mechanism 10 includes a first member 40 having a concave surface 72 formed by cutting out a portion of a spherical or conical surface into an annular shape, and a second member 42 disposed opposite the first member 40 and having a protrusion 80 that moves along the concave surface 72 of the first member 40 while in contact with the concave surface 72. The gripping mechanism 10 includes a connecting mechanism 44 that connects the first member 40 and the second member 42 and has a spring 102 that biases one of the first member 40 and the second member 42 toward the other. The gripping mechanism 10 allows the second member 42 to tilt relative to the first member 40 as the spring 102 flexes.

[0035] According to this embodiment, the concave surface 72 of the first member 40, which the convex portion 80 of the second member 42 moves while contacting, has a shape obtained by cutting out a part of a spherical or conical surface into an annular shape. Therefore, the gripping mechanism 10 can be made thinner than a mechanism in which a bowl-shaped support shaft is provided on the first member 40 and a spherical portion facing the inner surface of the bowl-shaped support shaft is formed on the second member 42.

[0036] Furthermore, the convex portion 80 of the second member 42 moves while abutting against the concave surface 72 of the first member 40. Therefore, in the gripping mechanism 10 of the present embodiment, frictional resistance is suppressed compared to a case in which the spherical portion formed on the second member 42 slides against the inner surface of the bowl-shaped support shaft of the first member 40 in surface contact, making it possible to smooth the movement of the second member 42 relative to the first member 40.

[0037] (2) In the gripping mechanism 10 , the convex portion 80 of the second member 42 is formed by a plurality of clamping screws 12 .

[0038] According to this embodiment, the clamping screw 12 is provided in the second member 42, thereby forming the convex portion 80 in the second member 42. In addition, since the convex portion 80 of the second member 42 is formed by the clamping screw 12, the contact state with the concave surface 72 of the first member 40 can be adjusted by the amount of screwing of the clamping screw 12.

[0039] The gripping mechanism 10 of this embodiment uses a clamping screw 12 having a sphere 12B rotatably provided at the tip of the screw body 12A. Therefore, the sphere 12B of the clamping screw 12 moves along the concave surface 72 while rotating, which makes it possible to further reduce the frictional resistance generated between the concave surface 72 and the convex portion 80.

[0040] (3) In the gripping mechanism 10, the concave surface 72 is formed at a position that overlaps with a spherical shape 74 that is centered on the part 22 gripped by the chuck 46.

[0041] According to this embodiment, the gripping mechanism 10 can tilt the second member 42 relative to the first member 40 around the part 22 gripped by the chuck 46. This causes the part 22 to tilt around the part 22. Therefore, the gripping mechanism 10 of this embodiment can improve the ease of attachment when attaching the part 22 held by the chuck 46 to the shaft of a pulley, for example, compared to a case in which the part 22 gripped by the chuck 46 is tilted around a point other than the center of the part 22.

[0042] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0043] In the above embodiment, the first member 40 having the concave surface 72 formed by cutting a part of a spherical surface into an annular shape is used as an example, but the gripping mechanism 10 is not limited to this configuration. The first member 40 may be configured as in the following modified example, for example.

[0044] 6 is a cross-sectional view showing a main part of a modified gripping mechanism 10. The modified gripping mechanism 10 includes a first member 40 having a concave surface 72 formed by cutting out a part of a conical surface 120 into an annular shape.

[0045] That is, in the embodiment described above, when the radius of the spherical shape 74 increases, the concave surface 72 along the spherical surface of the spherical shape 74 approaches an inclined surface. Therefore, even if the concave surface 72 is an inclined surface that overlaps with the conical surface 120 of the cone shape as in this modified example, the gripping mechanism 10 according to the modified example can obtain the same effects as described above.

[0046] In the above embodiment, the mounting portion 30 is provided on the first member 40 and the chuck 46 is provided on the second member 42, but the present embodiment is not limited to this structure. The gripping mechanism 10 of the present embodiment may have the mounting portion 30 provided on the second member 42 and the chuck 46 provided on the first member 40, for example.

[0047] In the above embodiment, the gripping mechanism 10 is attached to a robot, but the present embodiment is not limited to this configuration. The gripping mechanism 10 of the present embodiment may be applied to a device that moves the chuck 46 with a cylinder, for example.

[0048] In the above embodiment, the protruding portion 80 that contacts the concave surface 72 of the first member 40 is configured by a plurality of clamping screws 12, but the present embodiment is not limited to this configuration. In the gripping mechanism 10 of the present embodiment, the protruding portion 80 may be configured by a protrusion provided on the second member 42, for example. [Explanation of symbols]

[0049] 10 Gripping mechanism 12 Clamping screw 22 parts 40 First member 42 Second member 44 Connection mechanism 46 Chuck 72 Concave 76 Sphere center (center) 80 Convex 102 Spring

Claims

1. A gripping mechanism for gripping a part, comprising: A first member having a concave surface formed by cutting out a part of a spherical or conical surface into a circular shape; a second member disposed opposite to the first member and having a protrusion that moves along the concave surface of the first member while being in contact with the concave surface; a connecting mechanism that connects the first member and the second member and has a spring that biases one of the first member and the second member toward the other; Equipped with The spring is deflected to allow the second member to incline relative to the first member. Gripping mechanism.

2. 2. The gripping mechanism according to claim 1, The protruding portion of the second member is composed of a plurality of clamping screws. Gripping mechanism.

3. The gripping mechanism according to claim 1 or 2, The second member further includes a chuck. The concave surface is formed at a position overlapping with a spherical shape having the part gripped by the chuck as its center. Gripping mechanism.

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