JP2021066002A - Gripping mechanism and assembling device - Google Patents

Abstract

To provide a low-cost gripping mechanism that hardly fails.SOLUTION: A gripping mechanism 3 comprises a frame body 31 and a plurality of movable bodies 32. The frame body 31 stores the plurality of movable bodies 32. The movable body 32 has a basic shape of a rotary spheroid, which grips an object 4, at a space between an outer surface of the movable body 32 and an inner surface of the frame body 31 by action of gravity acting on the movable body 32. Preferably, the movable body 32 has a flat part 331 on an outer surface of a position where the body contacts the object 4. Further preferably, the movable body 32 has a core part 321 and a coating part 322. The coating part 322 coats a peripheral surface of the core part 321 with an elastic body.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gripping mechanism and an assembling device.

The assembly device described in Patent Document 1 includes a chuck mechanism for gripping parts for the purpose of transporting. The chuck mechanism is an electric gripping mechanism. In addition, a gripping mechanism using air suction or electric suction is also known.

Japanese Unexamined Patent Publication No. 7-241733

Since the conventional gripping mechanism uses power such as pneumatic energy or electric energy, it is costly and prone to failure.

Therefore, in consideration of the above circumstances, it is an object of the present invention to provide a gripping mechanism that is low in cost and less likely to break down, and an assembly device provided with the gripping mechanism.

The gripping mechanism of the present invention includes a plurality of movable bodies and a frame body. The frame body accommodates the plurality of movable bodies. Each of the plurality of movable bodies has a basic shape of a spheroid, and an object is gripped between the outer surface of the movable body and the inner surface of the frame body by the action of gravity acting on the movable body.

The assembly device of the present invention includes the gripping mechanism and a driving mechanism for moving the gripping mechanism relative to the object.

According to the present invention, it is possible to provide a gripping mechanism that is low in cost and less likely to break down, and an assembly device provided with the gripping mechanism.

It is a figure which shows an example of the assembly apparatus which concerns on embodiment. It is a front view which shows an example of the gripping mechanism which concerns on embodiment. It is an enlarged front view which shows an example of a gripping roller. FIG. 2 is an enlarged sectional view taken along line IV-IV of FIG. It is a perspective view which shows an example of the 1st part. FIG. 5 is a sectional view taken along line VI-VI of FIG. It is sectional drawing which shows the 1st stage of the operation of a gripping mechanism. It is sectional drawing which shows the 2nd stage of operation of a gripping mechanism. It is sectional drawing which shows an example of weight adjustment of a gripping roller. It is sectional drawing which shows the modification of the gripping roller.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8. In FIGS. 1 and 2, for convenience, the direction from left to right is the positive direction of the X axis, the direction from the back to the front is the positive direction of the Y axis, and the direction from top to bottom is the positive direction of the Z axis. And. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description is not repeated.

First, the assembly device 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram showing an example of the assembly device 100.

As shown in FIG. 1, the assembly device 100 is a device for assembling the first component 4 by fitting it into the second component 5. The assembly device 100 includes a robot 1, a misalignment correction device 2, and a gripping mechanism 3. The robot 1 corresponds to an example of a "drive mechanism".

The gripping mechanism 3 grips the first component 4. The second component 5 is positioned on the positioning mechanism 10. The first component 4 corresponds to an example of an "object".

The misalignment correction device 2 corrects the misalignment of the first component 4 gripped by the gripping mechanism 3 with respect to the second component 5. Specifically, the misalignment correction device 2 detects the direction of the force acting on the first component 4 when the first component 4 is fitted to the second component 5, and the first component 4 is subjected to the direction of the force. 1 Correct the misalignment of component 4.

The robot 1 moves the gripping mechanism 3 relative to the first component 4 and the gripping mechanism 3 relative to the second component 5. Specifically, the robot 1 moves the gripping mechanism 3 to the storage location of the first component 4, causes the gripping mechanism 3 to grip the first component 4, and then moves the first component 4 together with the gripping mechanism 3 to the second. Move it to just above the part 5. After that, the robot 1 fits the first component 4 into the second component 5 by moving the first component 4 together with the gripping mechanism 3 in the positive direction of the Z axis. After the fitting is achieved, the robot 1 releases the gripping mechanism 3 from the first component 4 and moves the gripping mechanism 3 in the negative direction of the Z axis.

Next, the gripping mechanism 3 according to the embodiment will be described with reference to FIGS. 2, 3, and 4. FIG. 2 is a front view showing an example of the gripping mechanism 3. FIG. 3 is an enlarged front view showing an example of the gripping roller 32. FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG.

As shown in FIG. 2, the gripping mechanism 3 includes a holder 31 and a plurality of gripping rollers 32. The longitudinal direction of the holder 31 and the longitudinal direction of each gripping roller 32 are both in the X-axis direction. The holder 31 corresponds to an example of a "frame body". The gripping roller 32 corresponds to an example of a “movable body”.

As shown in FIGS. 3 and 4, the gripping roller 32 has a basic shape of a spheroid whose rotation axis is the axis AX along the direction of the X axis, and has eight flat surfaces on the outer surface of the central portion in the longitudinal direction. It has portions 331, and has eight curved surface portions 332 on the outer surfaces of both ends in the longitudinal direction. The gripping roller 32 has a regular octagonal prism shape in the central portion of the total length W1 in the X-axis direction and having a length W2. The height of the regular octagonal prism corresponds to the length W2. The distance W3 between the opposite side surfaces of the regular octagonal prism is shorter than the total length W1.

As shown in FIG. 4, the gripping roller 32 has a columnar core portion 321 and a covering portion 322 that covers the peripheral surface of the core portion 321. For example, the core portion 321 is composed of a metal such as iron, and the coating portion 322 is composed of an elastic body such as polyacetal resin. The density of the core portion 321 is higher than the density of the covering portion 322. The covering portion 322 can be compressionally deformed. The outer surface of the covering portion 322 includes a flat portion 331 and a curved surface portion 332. The coefficient of friction of the outer surface of the covering portion 322 is larger than the coefficient of friction of the peripheral surface of the core portion 321.

As shown in FIG. 4, the holder 31 is a frame body for accommodating a plurality of gripping rollers 32, and includes a back plate 311 and a top plate 312, an upper front plate 313, a lower front plate 314, and left and right. It has a side plate 316. For example, the holder 31 is made of a light metal such as aluminum.

The back plate 311 is a rectangular plate extending along the ZX plane. The top plate 312 is a rectangular plate extending along the XY plane starting from the upper edge of the back plate 311. The upper front plate 313 is a rectangular plate extending diagonally downward in a direction away from the back plate 311 starting from the front edge of the top plate 312. The lower front plate 314 is a rectangular plate extending diagonally downward in a direction approaching the back plate 311 starting from the lower edge of the upper front plate 313.

An opening 315 is formed between the back plate 311 and the lower front plate 314. The width of the opening 315 in the Y-axis direction is smaller than the distance W3. Therefore, the gripping roller 32 does not fall through the opening 315. One of the eight flat portions 331 of the gripping roller 32 abuts on the back plate 311 and the other one of the eight flat portions 331 abuts on the lower front plate 314. The back plate 311 and the lower front plate 314 support the weight of the gripping roller 32. The opening 315 can receive the insertion of the gripping object.

The back plate 311, the top plate 312, the upper front plate 313, and the lower front plate 314 form substantially pentagonal openings on the left and right side surfaces of the holder 31, respectively. The left and right side plates 316 are arranged so as to close these openings. However, at least one side plate 316 has a notch 317 for passing an object to be gripped without passing through the gripping roller 32 at the time of releasing the grip at a position close to the back plate 311.

For example, by making the side plate 316 openable and closable, the gripping roller 32 can be taken in and out.

Next, the first component 4 will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective view showing an example of the first component 4. FIG. 6 is a sectional view taken along line VI-VI of FIG.

As shown in FIG. 5, the first component 4 includes a component body 41 and a gripped portion 42. The component body 41 has a substantially rectangular parallelepiped shape. The gripped portion 42 projects from the component body 41 so that it can be easily gripped by the gripping mechanism 3. The gripped portion 42 is formed in a rectangular plate shape, and the end surface of the gripped portion 42 is connected to one of the main surfaces of the component main body 41.

The gripped portion 42 has a first main surface 421 and a second main surface 422. The first main surface 421 and the second main surface 422 extend along the ZX plane. The first main surface 421 is located on the negative side of the Y-axis, and the second main surface 422 is located on the positive side of the Y-axis.

The gripped portion 42 further has two ribs 423 and 423. The two ribs 423 and 423 are provided at a distance from each other in the X-axis direction. Each rib 423 projects from the second main surface 422 in the positive direction of the Y-axis. Each rib 423 has an end face formed as an inclined surface 424 inclined with respect to the second main surface 422.

The second component 5 is a component body 51 having a substantially rectangular parallelepiped shape, in which a recess 52 for receiving the component body 41 of the first component 4 is formed.

As shown in FIG. 6, the gripped portion 42 has a first portion L1 and a second portion L2. The first portion L1 includes a negative end of the Z-axis of the gripped portion 42. The second portion L2 is connected to the first portion L1. The first portion L1 includes a part of the main surface of the plate-like body having a constant thickness t1, that is, a part of the second main surface 422. The second portion L2 has a thickness t2 that increases with distance from the connection with the first portion L1. The second portion L2 includes an inclined surface 424 formed on the rib 423.

Next, the operation of the gripping mechanism 3 will be described with reference to FIGS. 7 and 8. FIG. 7 is a cross-sectional view showing the first stage of the operation of the gripping mechanism 3. FIG. 8 is a cross-sectional view showing a second stage of the operation of the gripping mechanism 3.

As shown in FIG. 7, in the first stage, the gripping mechanism 3 grips the first component 4 between the outer surface of the gripping roller 32 and the inner surface of the holder 31 by the action of gravity acting on the gripping roller 32. Specifically, the second main surface 422 forming the first portion L1 of the gripped portion 42 is gripped between the outer surface of the covering portion 322 formed as the flat portion 331 and the inner surface of the back plate 311. The flat portion 331 realizes a large contact area between the covering portion 322 and the gripped portion 42. Moreover, due to the compression deformation of the covering portion 322, the contact area with the gripped portion 42 is further increased as compared with the case where the covering portion 322 is made of an inelastic body, and a large gripping force is realized.

As shown in FIG. 8, the gripping mechanism 3 moves relative to the first component 4 in the positive direction of the Z axis before the grip of the first component 4 is released. The operation of the gripping mechanism 3 shifts from the first stage to the second stage. In the second stage, the gripping roller 32 is lifted by the inclined surface 424 of the rib 423 forming the second portion L2 of the gripped portion 42. As a result, the posture of the gripping roller 32 is tilted, and the large gripping force of the covering portion 322 configured as the flat portion 331 is relaxed.

Hereinafter, the operation of the assembly device 100 will be described with reference to FIGS. 1 to 8.

In the first step, the robot 1 moves the gripping mechanism 3 to the storage location of the first component 4, as shown in FIG. Then, the robot 1 adjusts the posture of the gripping mechanism 3 so that the gripped portion 42 and the back plate 311 are parallel to each other, and then points the gripping mechanism 3 in the positive direction of the Z axis with respect to the first component 4. Move relative to. The gripped portion 42 enters the holder 31 through the opening 315 and rises in the holder 31 while pushing away the gripping roller 32. After that, the movement of the gripping mechanism 3 is stopped before the inclined surface 424 pushes up the gripping roller 32. As a result, the first stage state shown in FIG. 7 is realized. For the smooth movement of the gripping roller 32, the lower front plate 314 having an inner surface with a small coefficient of friction is effective.

In the second step, the robot 1 moves the gripping mechanism 3 in the negative direction of the Z axis. By further moving the gripping mechanism 3, the robot 1 conveys the first component 4 to just above the second component 5, as shown in FIG. The gripped portion 42 remains gripped between the outer surface of the covering portion 322 and the inner surface of the back plate 311.

In the third step, the robot 1 moves the gripping mechanism 3 in the positive direction of the Z axis. As a result, the first component 4 is fitted to the second component 5. The state of the first stage shown in FIG. 7 is maintained at least until just before fitting.

In the fourth step, the robot 1 further moves the gripping mechanism 3 in the positive direction of the Z axis. When the inclined surface 424 pushes up the gripping roller 32, the second stage state shown in FIG. 8 is realized. The second stage is a preparatory stage for releasing the grip.

In the fifth step, the robot 1 moves the gripping mechanism 3 in the positive direction of the X-axis. The gripped portion 42 slips between the outer surface of the covering portion 322 and the inner surface of the back plate 311 and further passes through the notch portion 317. As a result, the gripping mechanism 3 releases the gripping of the first component 4. The first component 4 remains fitted to the second component 5.

In the sixth step, the robot 1 returns the gripping mechanism 3 to its original position in preparation for the next work while moving the gripping mechanism 3 in the negative direction of the Z axis.

According to the embodiment, the gripping mechanism 3 that does not require power is configured only by the holder 31 and the plurality of gripping rollers 32. As a result, the gripping mechanism 3 which is low in cost and hard to break down is realized. Moreover, since each gripping roller 32 has a basic shape of a spheroid, interference between gripping rollers 32 adjacent to each other is reduced. As a result, when two or more gripping rollers 32 cooperate to grip the first component 4, even if the first component 4 swings during transportation and a certain gripping roller 32 tilts, the gripping mechanism 3 Since a stable gripping force can be obtained as a whole, the first component 4 is suppressed from falling off.

Next, the weight adjustment of the gripping roller 32 will be described with reference to FIG. FIG. 9 is a cross-sectional view showing an example of weight adjustment of the gripping roller 32.

The gripping roller 32 of FIG. 9 is different from the gripping roller 32 in FIG. 4 in that the diameter of the core portion 321 is reduced. If the materials of the core portion 321 and the covering portion 322 and the overall dimensions of the gripping roller 32 are the same, the smaller the diameter of the metal core portion 321, the smaller the weight of the gripping roller 32. On the contrary, the larger the diameter of the metal core portion 321 is, the heavier the weight of the gripping roller 32 is. It is also possible to adjust the weight of the gripping roller 32 by changing the material of at least one of the core portion 321 and the covering portion 322.

Finally, a modified example of the gripping roller 32 will be described with reference to FIG. FIG. 10 is a cross-sectional view showing a modified example of the gripping roller 32.

The gripping roller 32 of FIG. 10 differs from the gripping roller 32 of FIG. 4 in that it has an inner cylinder 323, an outer cylinder 324, and three cushion ribs 325, 325, and 325. The inner cylinder 323 and the outer cylinder 324 are octagonal cylinders having different dimensions from each other. The three cushion ribs 325, 325, and 325 connect between the inner cylinder 323 and the outer cylinder 324, respectively. Any two of the three cushion ribs 325, 325, and 325 are arranged at positions that deviate from each other by 180 degrees with respect to the central axis of the inner cylinder 323. The inner cylinder 323, the outer cylinder 324, and the three cushion ribs 325, 325, and 325 are all made of an elastic body such as polyacetal resin. The gripping roller 32 of FIG. 10 can be compressed and deformed as a whole, and a large gripping force can be realized.

Since the above description of each embodiment describes a preferred embodiment of the present invention, there may be various technically preferable limitations, but the technical scope of the present invention is particularly limited to the present invention. Unless otherwise specified, the present invention is not limited to these aspects. That is, the components in the above embodiment can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the above embodiment does not limit the content of the invention described in the claims.

For example, in the embodiment, as shown in FIGS. 3 and 4, the number of flat portions 331 is 8, but the number is not limited to this. The number of flat portions 331 may be 5 to 7, or 9 or more. Further, even when the flat portion 331 is not provided, as long as the gripping roller 32 has the basic shape of a spheroid, interference between the gripping rollers 32 adjacent to each other is reduced.

Further, in the embodiment, as shown in FIG. 5, the number of ribs 423 is 2, but the number is not limited to this. The number of ribs 423 may be 1 or 3 or more. Further, the gripped portion 42 may not be provided with a rib structure, and the gripped portion 42 may have a continuous inclined surface 424 over the entire width in the X direction.

The present invention is available in the field of gripping mechanisms and assembly devices.

1 Robot (drive mechanism)
3 Gripping mechanism 4 First part (object)
31 Holder (frame body)
32 Gripping roller (movable body)
100 Assembly device 311 Back plate (plate-shaped part)
314 Lower front plate (plate-shaped part)
315 Aperture 316 Side plate 317 Notch 321 Core 322 Cover 323 Inner cylinder 324 Outer cylinder 325 Cushion rib 331 Flat part

Claims (9)

With multiple movable bodies,
A frame body for accommodating the plurality of movable bodies is provided.
Each of the plurality of movable bodies has a basic shape of a spheroid, and a gripping mechanism that grips an object between the outer surface of the movable body and the inner surface of the frame body by the action of gravity acting on the movable body. .. The gripping mechanism according to claim 1, wherein each of the plurality of movable bodies has a flat portion on the outer surface at a position where the object comes into contact with the object. Each of the plurality of movable bodies has a core portion and a covering portion, and has a core portion and a covering portion.
The gripping mechanism according to claim 1 or 2, wherein the covering portion covers the peripheral surface of the core portion with an elastic body. The gripping mechanism according to claim 3, wherein the friction coefficient of the outer surface of the covering portion is larger than the friction coefficient of the peripheral surface of the core portion. The plurality of movable bodies each have an inner cylinder, an outer cylinder, and a plurality of cushion ribs.
The gripping mechanism according to any one of claims 1 to 4, wherein each of the plurality of cushion ribs connects between the inner cylinder and the outer cylinder. The gripping mechanism according to claim 5, wherein any two of the plurality of cushion ribs are arranged at positions deviating from each other by 180 degrees with respect to the central axis of the inner cylinder. Each of the frames has two plate-like portions that support the weight of the plurality of movable bodies.
The gripping mechanism according to any one of claims 1 to 6, wherein an opening for receiving the insertion of the object is formed between the two plate-shaped portions. The frame has a side plate and has a side plate.
The gripping mechanism according to any one of claims 1 to 7, wherein the side plate has a notch for passing the object without passing through the plurality of movable bodies. The gripping mechanism according to any one of claims 1 to 8.
An assembly device including a drive mechanism that moves the gripping mechanism relative to the object.

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