Suction pad

Abstract

To provide a suction pad which can inhibit deformation of a workpiece.SOLUTION: A suction pad for suctioning a workpiece W includes: a body part 70 connected to an air pipe and having a suction surface 76a configured to generate a negative pressure by air to suction the workpiece W; and a pad part 80 which is formed in an annular shape so as to enclose the suction surface 76a; and a cover part 78 which has better air permeability than that of the pad part 80 and covers the suction surface 76a so as to close a suction port 76b formed on at least the suction surface 76a.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a suction pad of a work transfer device.

Background Art

[0002] Conventionally, by using a work transfer device such as a palletizing robot, the automation of depalletizing work (or palletizing work, the same hereinafter) for a bag body or the like has been carried out. As a robot hand used for such automation of depalletizing work, for example, a suction pad described in Patent Document 1 is known.

[0003] In Patent Document 1, after bringing the suction pad into contact with the work to be depalletized, a vacuum suction force is applied to suck and lift the work with the suction pad, and it is carried in the lifted state. Note that such a suction pad may sometimes be called a vacuum gripper.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, a work such as a bag body containing rice, grains, etc. is heavy, has no specific entity, and is easily deformed. For this reason, when sucking, it is necessary to increase the negative pressure or the suction of air, and a part of the work is drawn inside. Thus, when the negative pressure or the suction of air is increased and the work is drawn into the suction pad, the work may be drawn into the suction port where air is sucked, and the work may be deformed or may leave a mark.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a suction pad capable of suppressing deformation of a workpiece.

Means for Solving the Problems

[0007] The means for solving the above problems is a suction pad used in a workpiece transfer device that transfers the workpiece in a state where the workpiece is sucked, and includes a main body portion having an air pipe connected thereto and a suction surface for sucking the workpiece by air, a pad portion formed in an annular shape so as to surround the suction surface, and a cover portion that has better air permeability than the pad portion and covers the suction surface so as to block at least the suction ports formed on the suction surface.

[0008] As shown in the above means, by covering the suction ports with the cover portion, it is possible to prevent the workpiece from being drawn into the suction ports and suppress deformation of the workpiece.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the "adsorption pad" according to the present invention will be described with reference to the drawings. In the following embodiments and modifications, parts that are identical or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the parts with the same reference numerals is incorporated herein. Also, in the description of the embodiments and modifications, not only the combinations of the explicitly shown configurations, but also the embodiments and modifications can be combined as long as there is no problem with the combination.

[0011] As shown in FIG. 1, the work transfer device 10 is a device that sequentially transfers a work W (see FIG. 10) from a supply location, aligns it, and stacks it on a portable pallet P installed at a predetermined position, that is, a device that performs palletizing. Note that the work transfer device 10 is also a device that sequentially transfers the work W aligned and stacked on a portable pallet P installed at a predetermined position to a predetermined discharge location, that is, a device that performs depalletizing. When performing depalletizing, basically, the reverse operation of the case of performing palletizing may be performed. Therefore, in this embodiment, palletizing will be mainly described.

[0012] As shown in FIG. 10, the work W is mainly assumed to be a bag containing rice, grains, etc. Note that the object contained in the bag may be a liquid, powder, or granular material, and for example, may be a plastic raw material composed of granular materials, wheat flour, or the like. The work W is not necessarily limited to these, and may be a container such as a cardboard box or a plastic case, a plastic part, a metal part, etc., as long as it is a work having an adsorbable surface.

[0013] The work W is supplied from an external transfer facility (such as a belt conveyor) to a roller conveyor 1 provided in the work transfer device 10. Then, the supplied work W is positioned and stopped at a predetermined stationary position by a stopper (not shown) provided on the roller conveyor 1. The work transfer device 10 is configured to detect and adsorb the work W positioned and stationary on the roller conveyor 1 using a sensor or the like and transfer it.

[0014] In the case of performing depalletizing, the reverse operation of the above-described palletizing is performed. That is, the work W is adsorbed from the pallet P by the work transfer device 10 and discharged to external transfer facilities via the roller conveyor 1 or the like.

[0015] Next, the configuration of the work transfer device 10 will be described in detail. As shown in FIG. 1, the work transfer device 10 includes a suction pad 20 that adsorbs the work W, a transfer mechanism 30 that moves the suction pad 20, and a rectangular parallelepiped frame body 65 to which the transfer mechanism 30 is fixed. Further, the work transfer device 10 includes a control device 100 that controls the operations of the suction pad 20 and the transfer mechanism 30, and a controller (not shown) as an information terminal capable of inputting and outputting various information.

[0016] In the present embodiment, the longitudinal direction of the frame body 65 is defined as the X-axis direction, the short-side direction (the direction perpendicular to the X-axis) is defined as the Y-axis direction, and the direction perpendicular to the X-axis direction and the Y-axis direction is defined as the Z-axis direction. Since the work transfer device 10 is usually installed on a plane, the Z-axis direction corresponds to the vertical direction (the vertical direction). Further, the X-axis direction and the Y-axis direction correspond to the horizontal direction.

[0017] The transfer mechanism 30 has a column portion 50 that is fixed to the frame body 65 and is formed to extend along the Z-axis direction, and an arm portion 60 that is fixed to the column portion 50 and is formed to extend along the Y-axis direction.

[0018] An X-axis guide rail 51 is provided on the frame body 65 along the X-axis direction, and the column portion 50 is fixed to be movable along the X-axis direction with respect to the X-axis guide rail 51. The column portion 50 is drivingly connected to the output shaft of an X-axis servo motor (not shown) disposed at the bottom of the frame body 65 via a toothed belt or the like. That is, the column portion 50 is configured to reciprocate in the X-axis direction along the X-axis guide rail 51 based on the driving force of the X-axis servo motor.

[0019] On the column part 50, a Z-axis guide rail 61 is provided along the Z-axis direction, and the arm part 60 is fixed to the Z-axis guide rail 61 so as to be movable along the Z-axis direction. The arm part 60 is drivingly connected to the output shaft of a Z-axis servo motor provided on the column part 50 via a toothed belt or the like. That is, the arm part 60 is configured to reciprocate in the Z-axis direction along the Z-axis guide rail 61 based on the driving force of the Z-axis servo motor.

[0020] On the arm part 60, a Y-axis guide rail 21 is provided along the Y-axis direction, and the suction pad 20 is fixed to the Y-axis guide rail 21 so as to be movable along the Y-axis direction. The suction pad 20 is drivingly connected to the output shaft of a Y-axis servo motor provided on the arm part 60 via a toothed belt or the like. That is, the suction pad 20 is configured to reciprocate in the Y-axis direction along the Y-axis guide rail 21 based on the driving force of the Y-axis servo motor.

[0021] As described above, the transfer mechanism 30 is configured such that the suction pad 20 can linearly move in two directions (X-axis direction and Y-axis direction) orthogonal to each other in the horizontal direction and in the vertical direction (Z-axis direction).

[0022] As shown in FIG. 1, the suction pad 20 is fixed to the arm part 60 via a rotation mechanism 23 as a turning part. The rotation mechanism 23 is configured to be able to turn the suction pad 20 around the Z-axis (in the direction of arrow R in FIG. 1) around the rotation mechanism 23 based on the driving force of a built-in turning servo motor (not shown).

[0023] As shown in FIG. 2, the suction pad 20 includes a main body portion 70 that generates a negative pressure to suction the workpiece W, and a pad portion 80 that is attached to the main body portion 70 and contacts the workpiece W. The suction pad 20 is connected to an ejector via an air pipe (not shown). By the operation of the ejector, the inside of the suction pad 20 becomes a negative pressure, and thus it is possible to suction the upper surface of the workpiece W. Note that, among the suction pad 20, the portion that directly contacts the workpiece W is made of sponge and is configured to be able to absorb the unevenness on the surface of the workpiece W to a certain extent. The detailed configuration of the suction pad 20 will be described later.

[0024] Next, the control device 100 will be described. The control device 100 is an electronic control device including a well-known microcomputer composed of a CPU, a ROM, a RAM, a flash memory, etc. The control device 100 includes a drive circuit for driving the various servo motors described above, and is configured to be able to control the operations of the various servo motors via the drive circuit.

[0025] This control device 100 is connected to various sensors, various servo motors, a controller, etc., and is configured to be able to acquire various information. Further, the control device 100 has various functions and executes the various functions based on the acquired various information. These functions are realized by executing a program stored in a storage device (storage memory) provided in the control device 100. Note that the various functions may be realized by an electronic circuit that is hardware, or at least a part thereof may be realized by software, that is, a process executed on a computer.

[0026] Among various functions, for example, there is a palletizing function of conveying the work W and loading it onto the pallet P. Briefly explaining the palletizing function, the control device 100 moves the suction pad 20 based on the position of the work W detected by a sensor or the like, or moves the suction pad 20 to a previously stored teaching position, sucks the work W by the suction pad 20, and conveys the work W onto the pallet P by the conveying mechanism 30. With this function, the work W is loaded on the pallet P in one or multiple rows in a predetermined direction (for example, the X-axis direction or the Y-axis direction). At that time, the work W may be stacked in multiple stages in the vertical direction (Z-axis direction).

[0027] In addition, among various functions, for example, there may be a depalletizing function of conveying the work W loaded on the pallet P one by one. Briefly explaining the depalletizing function, it detects the position of each work W loaded on the pallet P by a sensor or the like, moves the suction pad 20 based on the detected position, or moves the suction pad 20 to a previously stored teaching position, sucks the work W by the suction pad 20, and conveys it from the pallet P to a predetermined discharge location.

[0028] By the way, when the work W is a bag containing rice, grains, etc., it is heavy and easily deformed. Therefore, when sucking, it is necessary to increase the negative pressure or air suction to pull a part of the work W inward so that the suction pad 20 adheres more closely. When the negative pressure or air suction is increased in this way to make the suction pad 20 adhere closely, the work W may be deformed, or suction marks may be left by the pad portion 80 or the suction port 76b. This possibility is particularly high for the work W having a plastic bag. Therefore, it is desirable that the portion in contact with the work W is made of a soft and easily deformable sponge material.

[0029] However, if the sponge part is directly adhered to the non-deformable main body part 70 made of metal, resin, etc., the adhesion surface is likely to peel off due to excessive deformation of the sponge material during adsorption, resulting in durability problems. In particular, when lifting heavy objects, this tendency becomes prominent, and it has been necessary to frequently replace the sponge part. Therefore, in this embodiment, the suction pad 20 is configured as shown in FIGS. 2 to 9. This will be described in detail below.

[0030] As shown in FIG. 2, the main body part 70 includes a connection part 71 connected to the rotation mechanism 23, a vacuum port 72 connected to an air pipe and supplied with negative pressure by air, and a main body frame 73 to which the pad part 80 is attached. Hereinafter, in some cases, the side of the rotation mechanism 23 in FIG. 2 will be referred to as the upward direction, and the side of the pad part 80 in FIG. 2 will be referred to as the downward direction. Also, in some cases, the longitudinal direction of the pad part 80 will be simply referred to as the longitudinal direction, and the short-side direction of the pad part 80 will be simply referred to as the short-side direction.

[0031] The connection part 71 is made of plate-shaped metal and is connected and fixed to the rotation mechanism 23. Thereby, the suction pad 20 is connected to the transport mechanism 30. The vacuum port 72 is fixed to this connection part 71 by bolts or the like. An air pipe (not shown) is connected to the vacuum port 72 to supply negative pressure.

[0032] As shown in FIGS. 3 and 4, the main body frame 73 includes a bottomed cylindrical cup part 74, a pad frame 75 attached to an opening located below the cup part 74, and a suction prevention plate 76 disposed inside the pad frame 75. The suction prevention plate 76 may be disposed inside the cup part 74. FIG. 3 is an upper perspective view of the main body frame 73 and the pad part 80 when viewed from above (the side of the vacuum port 72), FIG. 4 is a cross-sectional view taken along line A-A of FIG. 3, and FIG. 5 is a cross-sectional view taken along line B-B of FIG. 3. In FIGS. 3 to 5, the illustration of the connection part 71, the vacuum port 72, etc. is omitted.

[0033] The cup portion 74 has an upper portion 74a to which the vacuum port 72 is fixed, and a wall portion 74b provided along the outer edge of the upper portion 74a and extending downward, and they are integrally formed. The upper portion 74a is formed in a plate shape that becomes a single concentric circle (a shape composed of a straight line and a semicircle) when viewed from the side (downward) of the workpiece W, and an exhaust port 77 is provided approximately at the center. The vacuum port 72 is fixed to the upper surface of the upper portion 74a. The exhaust port 77 of the upper portion 74a is connected to the vacuum port 72, and the air in the internal space of the main body frame 73 is sucked toward the vacuum port 72 through this exhaust port 77, and a negative pressure is supplied from the vacuum port 72.

[0034] As shown in FIGS. 3 to 5, a plurality of screw holes 74c are provided in the upper portion 74a, and long bolts 79a are screwed into these screw holes 74c and fixed by nuts 79c or the like. A plurality of (four in this embodiment) long bolts 79a extending toward the lower side (the side of the workpiece W) are provided in the upper portion 74a. The length from the upper portion 74a to the head 79d (tip) of the long bolt 79a is adjustable.

[0035] As shown in FIG. 8, the wall portion 74b is erected so as to surround the lower surface of the upper portion 74a at the outer edge of the upper portion 74a. That is, the wall portion 74b is configured in an annular shape that becomes a single concentric circle when viewed from the side (lower side) of the workpiece W. Further, as shown in FIG. 4 and the like, the open end of the wall portion 74b (that is, the end portion on the side of the workpiece W) is formed in a skirt shape so as to expand outward and is configured to be wide.

[0036] And, a pad frame 75 is fixed to the open end of the cup portion 74 with screws or the like. A rubber seal member is disposed between the cup portion 74 and the pad frame 75 and is configured to suppress air leakage. The pad frame 75 is configured in an annular shape that forms a single concentric circle when viewed from the side of the work W, similar to the open end of the cup portion 74, more specifically, the wall portion 74b. A flange 75a that extends outward is formed at the open end (the end on the work W side) of the pad frame 75. Further, the cup portion 74 and the pad frame 75 are formed of a rigid body such as metal or resin that does not deform even when negative pressure is supplied by an ejector.

[0037] As shown in FIGS. 4 to 8, the suction prevention plate 76 is constituted by a metal plate, and the surface on the work side is covered by a cover portion 78. Note that FIG. 6 is a bottom perspective view of the main body frame 73 and the pad portion 80 when viewed from the lower side (the side of the work W). FIG. 7 is a bottom perspective view of the main body frame 73 and the pad portion 80 when the cover portion 78 is removed. Further, FIG. 8 is a bottom perspective view of the main body frame 73 and the pad portion 80 when the cover portion 78 and the suction prevention plate 76 are removed.

[0038] As shown in FIG. 4, in the vertical direction, the suction prevention plate 76 is disposed at a position away from the upper portion 74a of the cup portion 74, and in this embodiment, inside the pad frame 75 and at a position overlapping the pad frame 75. The suction prevention plate 76 is disposed so as to overlap the exhaust port 77 so as to block at least the exhaust port 77 when viewed from the work W.

[0039] In this embodiment, as shown in FIG. 7 and the like, the suction prevention plate 76 is constituted by a single concentric circle metal plate so as to substantially block the inside of the pad frame 75. A plurality of suction ports 76b serving as air suction ports are formed through the suction prevention plate 76. Note that the shape of the suction port 76b is arbitrary and may be an elongated hole shape or a polygonal hole. However, it is desirable that the hole has a diameter or width smaller than that of the exhaust port 77 provided in the upper portion 74a of the cup portion 74.

[0040] As shown in FIG. 5, the suction prevention plate 76 is provided with an insertion hole 76c through which the long bolt 79a is inserted. The long bolt 79a is inserted through the insertion hole 76c and fixed by the head 79d of the long bolt 79a and the nut 79b. Note that the long bolt 79a corresponds to a fastening component that fixes the suction prevention plate 76 to the main body frame 73 of the main body portion 70.

[0041] Since the suction prevention plate 76 is fixed at a position away from the upper portion 74a, a space surrounded by the cup portion 74, the pad frame 75, and the suction prevention plate 76 is formed in the main body frame 73. As described above, the length dimension of the long bolt 79a, that is, the distance from the upper portion 74a to the head 79d of the long bolt 79a is adjustable. Therefore, in the vertical direction (= the plate thickness direction of the suction prevention plate 76), the distance from the upper portion 74a to the suction prevention plate 76 is similarly adjustable, and the size of the space surrounded by the cup portion 74, the pad frame 75, and the suction prevention plate 76 is also adjustable.

[0042] When a negative pressure is supplied to the main body frame 73 through the vacuum port 72, the space surrounded by the cup portion 74, the pad frame 75, and the suction prevention plate 76 becomes a negative pressure. Therefore, air is sucked in from the suction port 76b of the suction prevention plate 76, and the work W is adsorbed. For this reason, the surface of the suction prevention plate 76 (the surface on the side of the work W) is the adsorption surface 76a.

[0043] As described above, when the work W is strongly sucked into the suction port 76b of the adsorption surface 76a, a suction trace of the suction port 76b may remain. In consideration of this, the adsorption surface 76a of the suction prevention plate 76 is covered by the cover portion 78. The cover portion 78 is formed of a porous elastic body having air permeability. For example, the cover portion 78 is made of sponge, and more specifically, it is composed of an open-cell sponge having excellent air permeability and softness. Note that the cover portion 78 is formed of a material having higher flexibility than the suction prevention plate 76.

[0044] The cover portion 78 is provided so as to cover at least all the suction ports 76b. In the present embodiment, it is provided so as to cover the entire suction surface 76a of the suction prevention plate 76. Therefore, the cover portion 78 is formed in a single concentric circular plate shape when viewed from the side of the workpiece W. Further, the cover portion 78 has a predetermined thickness.

[0045] The surface 78b (the surface corresponding to the workpiece W) of the cover portion 78 is a flat surface, and the surface 78b of the cover portion 78 is disposed inside the pad portion 80 in the vertical direction. That is, the position of the suction prevention plate 76 in the vertical direction is adjusted so that the surface 78b of the cover portion 78 does not protrude beyond the pad portion 80 toward the workpiece W in the vertical direction.

[0046] This cover portion 78 is adhered to the suction surface 76a of the suction prevention plate 76 by a double-sided tape (not shown). For this reason, the cover portion 78 can be easily removed from the suction prevention plate 76.

[0047] Also, as shown in FIGS. 5 and 6, the cover portion 78 is provided with a through hole 78a penetrating in the thickness direction (vertical direction). As shown in FIGS. 6 to 8, this through hole 78a is provided corresponding to the position of the long bolt 79a, and is configured such that the head 79d of the long bolt 79a is exposed. For this reason, when adjusting the position of the suction prevention plate 76, etc., it is possible to insert a driver or the like into the through hole 78a and rotate the long bolt 79a without peeling off the cover portion 78. That is, it is possible to loosen or tighten the long bolt 79a without peeling off the cover portion 78.

[0048] Next, the pad portion 80 will be described with reference to FIGS. 4 and 9. The pad portion 80 is provided annularly along the pad frame 75 and is attached to the pad frame 75. That is, the pad portion 80 is formed in a single concentric circular ring shape when viewed from the workpiece W. As shown in FIG. 9, the pad portion 80 includes a sponge portion 83 as a contact portion that contacts the workpiece W, a rubber plate 81 as a cushion member interposed between the sponge portion 83 and the pad frame 75, a ring washer 82 for fixing the rubber plate 81, and the like.

[0049] The rubber plate 81 is made of rubber that is harder than the sponge portion 83 and is elastically deformable. Similar to the pad frame 75, it is configured in a single concentric circular ring shape so as to surround the suction surface 76a. The inner shape of this rubber plate 81 is configured to be substantially the same as the inner shape of the pad frame 75, that is, the inner shape of the cup portion 74. That is, the longitudinal dimension and the lateral dimension of the inner peripheral portion 81a of the rubber plate 81 are configured to be substantially the same as those of the cup portion 74.

[0050] On the other hand, the width dimension of the rubber plate 81 is formed wider than the width dimension of the pad frame 75. When the rubber plate 81 is attached to the pad frame 75, as shown in FIG. 4, it protrudes outward from the pad frame 75. For this reason, at least the protruding portion (the outer peripheral portion 81b protruding from the pad frame 75) of the rubber plate 81 is deformable in the vertical direction.

[0051] As shown in Fig. 9, the ring washer 82 is made of metal and has a single-centered circular ring shape similar to the shape of the inner peripheral portion 81a of the rubber plate 81. The width dimension of this ring washer 82 is formed narrower than the width dimension of the rubber plate 81. And the ring washer 82 is formed in accordance with the shape of the inner peripheral portion 81a of the rubber plate 81 and is overlapped on the inner peripheral portion 81a. Note that the outer peripheral portion 81b of the rubber plate 81 becomes the outer portion when the ring washer 82 is overlapped on the inner peripheral portion 81a of the rubber plate 81 and is configured not to overlap with the ring washer 82. This ring washer 82 is overlapped on the inner peripheral portion 81a of the rubber plate 81, sandwiches the inner peripheral portion 81a of the rubber plate 81 between it and the pad frame 75, and is fixed by a bolt 84 as a fastening member. That is, the rubber plate 81 is attached to the main body portion 70 by the ring washer 82 and the bolt 84.

[0052] The sponge portion 83 is made of a sponge material that is more easily deformed compared to the rubber plate 81. Also, the sponge portion 83 is made of a sponge that is less easily deformed compared to the cover portion 78, that is, a hard sponge, and is made of a sponge with poor air permeability compared to the cover portion 78. The sponge portion 83 of the present embodiment is made of a semi-open cell sponge.

[0053] The sponge portion 83 is configured in a single-centered circular ring shape similar to the rubber plate 81 and the pad frame 75. At that time, the outer shape of the sponge portion 83 is formed to be the same as the outer shape of the rubber plate 81. On the other hand, the width dimension of the sponge portion 83 is formed wider compared to the rubber plate 81 and the pad frame 75. That is, in the horizontal direction, a part of the inner peripheral portion 83a of the sponge portion 83 is formed to protrude inward from the rubber plate 81 and the pad frame 75.

[0054] Further, in the upper portion of the sponge portion 83 (the portion on the main body portion 70 side), a recessed portion 86 is provided in the inner peripheral portion 83a. This recessed portion 86 is provided so as to face the pad frame 75 of the main body portion 70 with the inner peripheral portions 81a of the ring washer 82 and the rubber plate 81 interposed therebetween. The depth dimension (dimension in the vertical direction) of this recessed portion 86 is provided to be approximately the same as or slightly deeper than the thickness dimension of the ring washer 82.

[0055] That is, the inner peripheral portion 83a of the sponge portion 83 is arranged so as to overlap the main body portion 70 in the vertical direction. Also, a gap is formed by the recessed portion 86 between the inner peripheral portion 83a of the sponge portion 83 and the inner peripheral portion 81a of the rubber plate 81, and the ring washer 82 and the head of the bolt 84 are arranged in this gap.

[0056] Further, the outer peripheral portion 83b of the sponge portion 83 (the portion outside the recessed portion 86) is adhered to the outer peripheral portion 81b of the rubber plate 81 that protrudes from the main body portion 70. In this embodiment, the outer peripheral portion 83b of the sponge portion 83 is adhered to the outer peripheral portion 81b of the rubber plate 81 that is outside the ring washer 82. As described above, the pad portion 80 is configured by overlapping the sponge portion 83 and the rubber plate 81 such that the rubber plate 81 is interposed between the main body portion 70 and the sponge portion 83.

[0057] Also, the dimension (thickness dimension) of the sponge portion 83 in the vertical direction is such that it can be deformed to an extent that can sufficiently absorb the unevenness on the surface of the work W when adsorbing the work W. Further, in the sponge portion 83, a tapered surface 85 is provided at the corner between its inner peripheral surface and the contact surface with the work W. That is, at the corner between the inner peripheral surface of the sponge portion 83 and the contact surface with the work W, chamfering is performed.

[0058] Next, the operation of the pad portion 80 during adsorption by the adsorption pad 20 will be described with reference to FIG. 10. In FIG. 10, the deformation of the pad portion 80 and the cover portion 78 is exaggerated for clarity.

[0059] When negative pressure is supplied to the inside of the adsorption pad 20, the pad portion 80 adheres to the surface of the workpiece W, and the workpiece W is adsorbed by sucking a part of the workpiece W inside. At this time, as shown in FIG. 10, a part of the surface of the workpiece W is sucked inside and attracted to the side of the suction prevention plate 76 by the suction force. However, even when attracted to the side of the suction prevention plate 76, since the cover portion 78 covers the adsorption surface 76a of the suction prevention plate 76, the workpiece W does not directly hit the suction port 76b, and it is difficult for a suction mark to be left on the workpiece W.

[0060] Further, the sponge portion 83 of the pad portion 80 is formed of a semi-open cell sponge (or closed cell sponge) that is less deformable than the cover portion 78, and the thickness dimension is thicker than that of the cover portion 78. The surface of the sponge portion 83 (the surface on the side of the workpiece W) is disposed on the side of the workpiece W (the lower side in FIG. 4) compared to the surface of the cover portion 78. Therefore, when the workpiece W is adsorbed, the sponge portion 83 is not completely crushed, and the elastic force thereof moderately pushes back the surface of the workpiece W. Thus, it is possible to prevent the cover portion 78 from being completely crushed and the surface of the workpiece W from being pressed against the adsorption surface 76a.

[0061] Further, in the sponge portion 83, a tapered surface 85 is provided at the corner between the inner peripheral surface thereof and the contact surface with the workpiece W. Also, a gap is formed between the inner peripheral portion 83a of the sponge portion 83 and the inner peripheral portion 81a of the rubber plate 81. As a result, the pad portion 80 is easily deformed inward, and when adsorbing the workpiece, a part of the workpiece is sucked inside the pad portion 80. Further, by the tapered surface 85, when a part of the workpiece W is sucked inside the pad portion 80, the corner of the sponge portion 83 can prevent the adsorption mark of the pad portion 80 from being left on the surface of the workpiece W.

[0062] Also, as shown in FIG. 10, when a part of the surface of the workpiece W is sucked inside, the sponge portion 83 also enters inward following the workpiece W. As a result, the outer peripheral portion 83b of the sponge portion 83 is pulled inward by the inner peripheral portion 83a of the sponge portion 83. Along with this, the outer peripheral portion 81b of the rubber plate 81 adhered to the outer peripheral portion 83b of the sponge portion 83 is also pulled downward inside.

[0063] At this time, the outer peripheral portion 81b of the rubber plate 81 is not adhered to the main body portion 70 and protrudes outside the main body portion 70. More specifically, in the horizontal direction, the outer peripheral portion 81b of the rubber plate 81 that is outside the ring washer 82 is not directly adhered to the main body portion 70. For this reason, the outer peripheral portion 81b of the rubber plate 81 can elastically deform downward (in the direction of the workpiece W) on the side of the sponge portion 83, that is, in FIG. 10. Therefore, the outer peripheral portion 81b of the rubber plate 81 is pulled by the outer peripheral portion 83b of the sponge portion 83 and deformed downward inside.

[0064] Also, the inner peripheral portion 81a of the rubber plate 81 is fixed to the main body portion 70 by a bolt 84 so as to be sandwiched by the ring washer 82. For this reason, the inner peripheral portion 81a of the rubber plate 81 can be deformed to a certain extent outward in the horizontal direction. Therefore, when the outer peripheral portion 81b of the rubber plate 81 deforms downward inside, the inner peripheral portion 81a of the rubber plate 81 extends outward to assist the downward deformation inside of the outer peripheral portion 81b of the rubber plate 81.

[0065] As described above, since the outer peripheral portion 81b of the rubber plate 81 moves downward inside following the deformation of the sponge portion 83, even if the outer peripheral portion 83b of the sponge portion 83 deforms, it is possible to suppress the adhesion surface between the outer peripheral portion 81b of the rubber plate 81 and the outer peripheral portion 83b from peeling off.

[0066] Note that the inner peripheral portion 83a of the sponge portion 83 is arranged so as to overlap with the main body portion 70, more specifically, the ring washer 82, in the vertical direction. Therefore, when a part of the workpiece W is sucked into the inside of the pad portion 80, the inner peripheral portion 83a of the sponge portion 83 is pressed against the main body portion 70 via the ring washer 82. For this reason, it is possible to suppress the inner peripheral portion 83a of the sponge portion 83 from being excessively deformed and entering the inside of the main body frame 73, and it is possible to suppress the outer peripheral portion 81b of the rubber plate 81 from being excessively deformed.

[0067] The effect of the suction pad 20 described in the above embodiment will be described.

[0068] A rubber plate 81 that is harder than the sponge portion 83 and does not deform as much as the sponge portion 83 is interposed between the main body portion 70 and the sponge portion 83. Thereby, when the workpiece W is adsorbed, even if the sponge portion 83 is excessively deformed, the rubber plate 81 does not deform excessively accordingly. That is, the strain between the sponge portion 83 and the rubber plate 81 and the strain between the main body portion 70 and the rubber plate 81 can be reduced. Therefore, it is possible to suppress the adhesive surface from peeling off and the pad portion 80 from being damaged, and the durability of the pad portion 80 can be improved.

[0069] Since the outer peripheral portion 81b of the rubber plate 81, which is the bonding portion with the sponge portion 83, is not directly fixed to the main body portion 70, the amount of deformability toward the sponge portion 83 is large. For this reason, even if the workpiece W is sucked into the inside of the pad portion 80, that is, the inside of the sponge portion 83, and the outer peripheral portion 83b of the sponge portion 83 is greatly deformed so as to be drawn inward and downward, the outer peripheral portion 81b of the rubber plate 81 can deform following it. Thereby, the strain between the main body portion 70 and the rubber plate 81 can be reduced, and it is possible to suppress the pad portion 80 from being damaged.

[0070] Since the inner peripheral portion 81a of the rubber plate 81 is sandwiched between the ring washer 82 and the main body 70, even when fastening with the bolt 84, a gap is formed between the main body 70 and the rubber plate 81, and it is possible to prevent air from leaking. In particular, since the rubber plate 81 is elastically deformable, it can be brought into close contact with the main body 70.

[0071] Also, by fixing the rubber plate 81 with the bolt 84, compared with the case of adhering with an adhesive or the like, it becomes easier to replace the pad portion 80. Also, compared with the case of adhesion, since the rubber plate 81 is more likely to extend outward in the horizontal direction, even if the inner peripheral portion 81a of the rubber plate 81 is pulled outward along with the deformation of the outer peripheral portion 81b, it is possible to suppress the rubber plate 81 from peeling or tearing.

[0072] In the sponge portion 83, a tapered surface 85 is provided at the corner between the inner peripheral surface and the contact surface with the workpiece W. As a result, the inner peripheral portion 83a of the sponge portion 83 becomes thinner toward the inside, and the pad portion 80 is more likely to deform inward. For this reason, when adsorbing the workpiece W, it becomes easier to suck a part of the workpiece W inside the pad portion 80, and it is possible to prevent the pad portion 80 from spreading outward. In particular, the outer peripheral portion 83b of the sponge portion 83 is fixed to the outer peripheral portion 81b of the rubber plate 81 protruding outward from the main body 70, and even when the pad portion 80 is likely to spread outward, it is possible to prevent the pad portion 80 from spreading outward. Therefore, the workpiece W can be reliably adsorbed.

[0073] The inner peripheral portion 81a of the sponge portion 83 is arranged so as to overlap the main body 70. When the workpiece W is sucked in, the inner peripheral portion 83a of the sponge portion 83 can be pressed against the main body 70. Thereby, when the workpiece W is sucked in, it is possible to prevent the sponge portion 83 from deforming excessively inward and, accordingly, the rubber plate 81 from deforming excessively.

[0074] A gap is formed by a recessed portion 86 between the inner peripheral portion 83a of the sponge portion 83 and the inner peripheral portion 81a of the rubber plate 81. That is, the inner peripheral portion 83a of the sponge portion 83 is thinner than the outer peripheral portion 83b and is more likely to be crushed. Thus, when the work W is adsorbed, the gap due to the recessed portion 86 is crushed, making it easier for the pad portion 80 to deform inward. Therefore, it becomes easier to suck a part of the work W into the inside of the pad portion 80, and it is possible to prevent the pad portion 80 from expanding outward.

[0075] The heads of the ring washer 82 and the bolt 84 are disposed in the gap formed between the inner peripheral portion 83a of the sponge portion 83 and the inner peripheral portion 81a of the rubber plate 81. Thereby, even if the work W is sucked into the inside of the pad portion 80, it is possible to prevent the work W from being damaged by contacting the ring washer 82 and the bolt 84. Further, since the sponge portion 83 is easily deformable, when replacing the pad portion 80, the inner peripheral portion 83a of the sponge portion 83 can be deformed to easily expose the bolt 84. Thereby, the replacement of the pad portion 80 becomes easy and the maintainability is improved.

[0076] The cover portion 78, which has better air permeability than the pad portion 80 and is formed of a material with higher flexibility than the suction prevention plate 76, covers the suction surface 76a so as to close the suction port 76b. Thereby, it is possible to prevent the work W from being drawn into the suction port 76b and suppress the suction mark of the suction port 76b on the work W.

[0077] In the vertical direction (plate thickness direction), the position of the suction prevention plate 76 with respect to the main body portion 70 is configured to be adjustable. Therefore, the size of the space surrounded by the cup portion 74, the pad frame 75, and the suction prevention plate 76 is also adjustable. And by changing the size of this space, the magnitude of the negative pressure during suction can be changed. Therefore, by adjusting the position of the suction prevention plate 76, the negative pressure during suction can be set to an appropriate magnitude, and it can be changed to a negative pressure at which the work W is less likely to have a suction mark.

[0078] The cover portion 78 is provided with a through hole 78a for exposing the long bolt 79a. Thereby, when adjusting the position of the suction prevention plate 76 or the like, it is possible to loosen or tighten the long bolt 79a by inserting a driver or the like into the through hole 78a without removing the cover portion 78.

[0079] The cover portion 78 is formed of a porous elastic body, has good air permeability, and is easily deformed. Therefore, it is optimal as a cover for covering the adsorption surface 76a. Further, the cover portion 78 is detachably provided on the adsorption surface 76a by a double-sided tape, is easy to replace, and has excellent maintainability.

[0080] In addition, since the sponge portion 83 is provided with a tapered surface 85, even if the work W is drawn into the inside of the pad portion 80, it is possible to suppress the formation of suction marks on the work W by the corner portion between the inner peripheral surface of the sponge portion 83 and the contact surface.

[0081] In addition, as described above, the outer peripheral portion 83b of the sponge portion 83 protrudes outward from the main body portion 70 and is adhered to the outer peripheral portion 81b of the rubber plate 81. Thereby, the pad portion 80 is easily deformed, and even if the work W is drawn into the inside of the pad portion 80, it is possible to suppress the formation of suction marks on the work W.

[0082] In addition, a gap is formed by the recessed portion 86 between the inner peripheral portion 83a of the sponge portion 83 and the inner peripheral portion 81a of the rubber plate 81. Thereby, when adsorbing the work W, the gap due to the recessed portion 86 is crushed, so that the pad portion 80 is easily deformed inward. Therefore, even if the work W is drawn into the inside of the pad portion 80, it is possible to suppress the formation of suction marks on the work W.

[0083] (Modified Example) Hereinafter, a modified example in which a part of the suction pad 20 in the above embodiment is changed will be described.

[0084] ·In the above-described embodiment, the outer peripheral portion 81b of the rubber plate 81 protruded outward in the horizontal direction from the main body portion 70, but it does not have to protrude. In this case, the outer peripheral portion 83b of the sponge portion 83 may be adhered to the outer peripheral portion 83b of the rubber plate 81 that is not directly fixed to the main body portion 70 (for example, the portion outside the ring washer 82).

[0085] ·In the above-described embodiment, the inner peripheral portion 81a of the rubber plate 81 was fixed to the main body portion 70 by bolts 84, but it may be fixed by adhesion. In this case, the outer peripheral portion 83b of the sponge portion 83 may be adhered to the portion of the outer peripheral portion 81b of the rubber plate 81 that is not adhered to the main body portion 70 (the portion outside the adhered portion).

[0086] ·In the suction pad 20 of the above-described embodiment, if air is used for suction, the suction mechanism may be arbitrarily changed. For example, instead of an ejector, an air pipe connected to a blower such as a ring blower may be connected to the suction pad 20, and suction may be performed by sucking air. ·In the above-described embodiment, the tapered surface 85 does not have to be provided.

[0087] ·In the above-described embodiment, a curved surface may be provided instead of the tapered surface 85. That is, the corners may be rounded. ·In the above-described embodiment, the thickness dimensions of the cover portion 78 and the sponge portion 83 may be arbitrarily changed.

[0088] ·In the above-described embodiment, a gap does not have to be provided between the inner peripheral portion 83a of the sponge portion 83 and the ring washer 82.

[0089] ·In the above-described embodiment, the cover portion 78 may be adhered to the suction prevention plate 76 with an adhesive.

[0090] ·In the above-described embodiment, the shape of the cover portion 78 may be arbitrarily changed. Also, the through hole 78a does not have to be provided.

[0091] ·In the above embodiment, the shapes of the pad frame 75 and the pad portion 80 are single concentric circles, but they are not limited to single concentric circles and may be arbitrarily changed. For example, they may be elliptical, substantially square, two-concentric circles, three-concentric circles, or other shapes.

[0092] ·In the above embodiment, the cover portion 78 is provided with a through hole 78a to expose the head 79d of the long bolt 79a. However, if the head 79d of the long bolt 79a can be exposed, a notch or the like may be provided.

Description of Reference Numerals

[0093] 10…Work transfer device, 20…Suction pad, 70…Main body portion, 72…Vacuum port, 73…Main body frame, 74…Cup portion, 75…Pad frame, 76…Suction prevention plate, 76a…Suction surface, 76b…Suction port, 80…Pad portion, 81…Rubber plate, 82…Ring washer, 83…Sponge portion, 100…Control device.

Claims

1. An adsorption pad used in a work transfer device for transferring a work while adsorbing the work, comprising: a main body portion to which an air pipe is connected and which has an adsorption surface for adsorbing the work by air; a pad portion formed in an annular shape so as to surround the adsorption surface; a cover portion that has better air permeability than the pad portion and covers the adsorption surface so as to block at least the suction ports formed on the adsorption surface.

2. The main body portion has a metal plate on one surface of which the adsorption surface is formed, a plurality of suction ports penetrating in the plate thickness direction are formed in the metal plate, the cover portion covers the plurality of suction ports so as to cover the adsorption surface of the metal plate, The adsorption pad according to claim 1, wherein the cover portion is formed of a material having higher flexibility than the metal plate.

3. The adsorption pad according to claim 2, wherein in the plate thickness direction, the position of the metal plate with respect to the main body portion is configured to be adjustable inside the pad portion.

4. The metal plate is configured to be fixed to the main body portion by fastening components, The adsorption pad according to claim 3, wherein the cover portion is provided with a through hole or a notch for exposing the fastening components.

5. The adsorption pad according to any one of claims 1 to 4, wherein the cover portion is formed of a porous elastic body.

6. The adsorption pad according to any one of claims 1 to 4, wherein the surface of the cover portion corresponding to the work is a flat surface.

7. The adsorption pad according to any one of claims 1 to 4, wherein the cover portion is detachably provided on the adsorption surface by a double-sided tape.

8. The adsorption pad according to any one of claims 1 to 4, wherein a tapered surface or a curved surface is provided at a corner between the inner peripheral surface of the pad portion and the contact surface of the work.

9. The pad portion has a contact portion that contacts the work and a cushion member that is attached to the main body portion and is elastically deformable, and they are stacked so that the cushion member is interposed between the main body portion and the contact portion, the cushion member is configured in an annular shape surrounding the adsorption surface, an outer peripheral portion of the cushion member is not fixed to the main body portion and is deformable toward the contact portion side. The contact portion is configured in an annular shape and adhered to the outer peripheral portion of the cushion member. The suction pad according to any one of claims 1 to 4.

10. A suction pad according to claim 9, wherein a gap is formed between the inner peripheral portion of the contact portion and the main body portion or the cushion member.

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