Adsorption pad

Abstract

To provide an adsorption pad that is configured so as to be suppressed from turning up when adsorbing a work-piece to be adsorbed.SOLUTION: An adsorption pad 11, which adsorbs a work-piece 17 and is connected to a vacuum generator, comprises a skirt part 59 and a plurality of ribs 61 formed inside the skirt part 59 to contact the work-piece 17, where a first contact point closest to a central axis of first contact points at which the ribs 61 contact the work-piece 17 is positioned in a line connecting second contact points close to the central axis, of second contact points at which the plurality of ribs 61 contact the skirt part 59.SELECTED DRAWING: Figure 8A

Description

[Technical Field]

[0001] The present invention relates to a suction pad. [Background technology]

[0002] Conventionally, there has been known an adsorption pad that is fixed to the end of a body having a passage therein through which a negative pressure fluid is supplied, and that has ribs on the adsorption surface of the adsorption portion that adsorbs the workpiece, the ribs protruding toward the workpiece side and being formed on the outer periphery of the passage and extending radially outward, and a plurality of second rib portions formed on the outer periphery of the first rib portions and arranged circumferentially offset from the first rib portions, a supply passage through which the negative pressure fluid flows is formed between adjacent first rib portions, and at least a portion of the second rib portions is arranged so as to face the extension direction of the supply passage (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-23022 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a suction pad that can suppress curling of the suction pad when suctioning a workpiece to be sucked. [Means for solving the problem]

[0005] One aspect of the present disclosure is an adsorption pad that adsorbs a workpiece and is connected to a vacuum generator, the adsorption pad comprising a skirt portion and a plurality of ribs that contact the workpiece and are formed inside the skirt portion, wherein the first contact point where the ribs come into contact with the workpiece and that is closest to the central axis of the adsorption pad is located within a line connecting the second contact points where the ribs come into contact with the skirt portion and that is closest to the central axis. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to prevent the suction pad from curling up when suctioning a workpiece to be sucked. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an external perspective view of a robot device having a suction pad in a suction hand according to a first embodiment of the present disclosure; [Figure 2] Perspective view of the manipulator [Figure 3] Cross-sectional view of the suction pad cut on a plane including the central axis [Figure 4] Bottom view of the suction pad seen from the suction opening direction (Z direction) [Figure 5] Enlarged view of the main part of Figure 4 [Figure 6] A perspective view of the suction pad cut along a plane parallel to the central axis [Figure 7] FIG. 10 is an enlarged perspective view of a main part of a suction pad according to a comparative example; [Figure 8A] Cross-sectional view of one side of the suction pad, cut along a plane including the central axis [Figure 8B] FIG. 1 is a diagram showing an example of the positional relationship between a first contact point P and a second contact point Q. [Figure 9] FIG. 10 is an explanatory diagram showing a suitable position of a notch provided in a rib. [Figure 10] 1 is a perspective view of a suction pad in which each rib is connected to another rib on the side of the central axis. [Figure 11] 1 is a perspective view of a suction pad in which each rib is connected to the central axis side via a predetermined member. [Figure 12] An explanatory diagram showing the process of suctioning a workpiece using a suction pad [Figure 13] 10 is an explanatory diagram of curling up that occurs in a suction pad according to a comparative example; [Figure 14] FIG. 10 is a schematic diagram illustrating the operation of a simplified suction pad according to a comparative example when bending occurs; [Figure 15]FIG. 10 is a schematic diagram illustrating the operation of a simplified suction pad according to the first embodiment when bending occurs; [Figure 16] Operation diagram of a suction pad with ribs that do not have notches when suctioning a workpiece [Figure 17] Operation diagram of a suction pad equipped with ribs having notches when suctioning a workpiece [Figure 18] An explanatory diagram of a rib provided with a bending prevention portion [Figure 19] An explanatory diagram of a rib with the apex of the triangular part cut off [Figure 20] An explanatory diagram of the rib shown in Figure 19 with the extension cut away. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed description of well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0009] (How the embodiment of the present disclosure was achieved) Research is being conducted into technologies for using robots and suction pads to pick a variety of products (items) in the distribution industry. Typically, suction pads are prepared for each product's packaging format. However, due to the diverse nature of products, there is a demand for a single suction pad that can handle multiple product characteristics and reduce changeover time. However, for example, to pick up a bag, a bag pad with a flexible skirt and ribs is required. However, when attempting to pick up a hard workpiece such as a can box using a bag pad, when a force is applied to press the suction pad against the workpiece, a rotational moment is generated around the point where the rib contacts the workpiece (the end of the first rib 46 on the side of the first communicating hole 40 in Patent Document 1), which can cause the skirt to turn up and result in failure to pick up the workpiece.

[0010] In the following embodiment, a suction pad that can suppress curling of the suction pad when suctioning a workpiece to be sucked and can facilitate successful suction of the workpiece will be described.

[0011] (Embodiment 1) 1 is an external perspective view of a robot device 15 having a suction pad 11 according to a first embodiment of the present disclosure on a suction hand 13. In the diagram with arrows indicating directions, the X axis indicates the front-to-rear direction, the Y axis indicates the left-to-right direction, and the Z axis indicates the up-to-down direction. The X axis and Y axis are orthogonal to each other and are included in a horizontal plane. The Z axis is included in a longitudinal plane.

[0012] The suction pad 11 can be suitably used in a robot device 15. Containers 19, cardboard boxes, etc., which carry workpieces 17 to be picked up, can freely enter and exit the robot device 15. For example, the robot device 15 can transfer cargo from a given container to another container, etc., and can perform cargo repacking between containers. The platform on which the containers are placed serves as a stage 21 for sorting.

[0013] A pair of columns 37 spaced apart in the X direction (front and back) are fixed to each of the left and right base beams 35 and stand upright in the Z direction. The upper ends of the four columns 37 support the four corners of a rectangular base frame 39 that surrounds a horizontal plane. A Y-axis rail 41 extending in the Y direction is supported on the base frame 39. An X-axis rail 43 extending in the X direction is supported on the Y-axis rail 41. A Z-axis rail 45 extending in the Z direction is supported on the X-axis rail 43.

[0014] A moving body 47 is provided on the Z-axis rail 45 so as to be movable up and down (Z direction). The moving body 47 may also be referred to as an actuator. The Z-axis rail 45 is translated along an X-axis rail 43 in the front-to-rear direction (X direction) perpendicular to the Z-axis rail 45. The X-axis rail 43 is translated along a Y-axis rail 41 in the left-to-right direction (Y direction) perpendicular to the X-axis rail 43 and the Z-axis rail 45. Therefore, the moving body 47 is movable up and down (Z direction), front-to-rear (X direction), and left-to-right (Y direction) relative to the stage 21.

[0015] The Z-axis rail 45 that moves the moving body 47, the X-axis rail 43 that moves the Z-axis rail 45 in a direction perpendicular to the Z-axis rail 45, and the Y-axis rail 41 that moves the X-axis rail 43 in a direction perpendicular to the X-axis rail 43 and the Z-axis rail 45 make up an Cartesian robot 49. The robot device 15 according to the first embodiment is configured by providing the Cartesian robot 49 with a suction hand 13. That is, the Cartesian robot 49 holds the suction hand 13 so that it can move freely in three directions that are perpendicular to one another. The Cartesian robot 49 also has a motor or the like that supplies a driving force to move the rails of each axis.

[0016] The robot device 15 also includes a control device (not shown) that controls each component of the robot device 15 (for example, the suction hand 13, the Cartesian robot 49).

[0017] A vacuum generator 51 is provided above the movable body 47. A support pipe 53 extending in the Z direction is fixed to the lower side of the movable body 47. The upper end (other end) of the support pipe 53 is fixed to the movable body 47 by a mounting piece (not shown). The vacuum generator 51 is connected to the upper end of the support pipe 53 by a connecting tube (not shown). That is, the inner diameter side of the support pipe 53 forms a vacuum path communicating with the negative pressure port and the atmospheric release port (not shown) of the vacuum generator 51. A suction pad 11 is fixed to the lower end (one end) of the support pipe 53. The suction pad 11 is a bellows type formed in a bellows shape. The movable body 47 and the vacuum generator 51 are included in the robot device 15, and may be included in the suction hand 13 or the Cartesian robot 49.

[0018] FIG. 2 is a perspective view of the manipulator.

[0019] The robot device 15 may be an automatic machine capable of picking and placing, such as a manipulator (arm robot 23). In this case, the manipulator has a base installed in a sorting area for the workpieces 17, a production line, or the like. The manipulator may include, for example, a swivel unit 25 attached to the top of the base and rotating horizontally, an upper arm 27 attached to the swivel unit 25 and swinging back and forth, a forearm 29 attached to the upper arm 27 and swinging up and down, and a wrist 33 attached to the forearm 29, having an adsorption pump 31, and having three degrees of freedom.

[0020] FIG. 3 is a cross-sectional view of the suction pad 11 taken along a plane including the central axis 55. As shown in FIG.

[0021] The suction pad 11 has a skirt portion 59 with a slope that is coaxially connected to the lower end of a pipe portion 57 that is connected to a support pipe 53 (see FIG. 1). The skirt portion 59 is formed in a truncated cone shape in side view, with the inner and outer peripheries sloped and gradually expanding in diameter toward the suction opening.

[0022] The inner diameter portion 52 of the pipe portion 57 communicates with the vacuum path of the vacuum generator 51 via a support pipe 53. An expanded diameter portion 54, which increases the inner diameter of the inner diameter portion 52, is formed at the boundary between the inner diameter portion 52 of the pipe portion 57 and the inside of the skirt portion 59. The inside of the skirt portion 59, which communicates with the inner diameter portion 52 via the expanded diameter portion 54 of the pipe portion 57, serves as a suction chamber. The suction pad 11 brings the suction opening on its underside into contact with the workpiece 17 to suction the workpiece 17. A plurality of ribs 61 are formed radially on the inner peripheral surface 56 of the skirt portion 59, centered on a central axis 55.

[0023] The rib 61 has a triangular portion 66 including a hypotenuse portion 62 that follows the slope of the skirt portion 59 and a base portion 64 that is parallel to the suction opening surface. The base portion 64 of the triangular portion 66 is positioned slightly back toward the suction chamber from the suction opening. The hypotenuse portion 62 and the base portion 64 of the triangular portion 66 are connected by a vertical side portion 68 that is perpendicular to the base portion 64. The rib 61 is formed so that an extension portion 63 protrudes from the vertical side portion 68 toward the central axis 55.

[0024] In the suction pad 11, the tube portion 57, skirt portion 59, and rib 61 are integrally formed from, for example, soft resin or rubber. When the skirt portion 59 is formed from, for example, rubber, it has a predetermined rubber hardness. The rubber hardness becomes softer as the numerical value decreases, and harder as the numerical value increases. For example, the hardness is about 10° for human skin and 60° or more for an automobile tire. The rubber hardness adopted for the skirt portion 59 in the first embodiment is preferably, for example, about 20° to 45°. In addition, the thickness of the tip of the skirt portion 59 is preferably 0.3 to 0.5 mm. By having the predetermined rubber hardness, the skirt portion 59 has adhesion to the workpiece 17, such as a bagged product, and shape stability.

[0025] FIG. 4 is a bottom view of the suction pad 11 as seen from the direction of the suction opening (Z direction).

[0026] The multiple ribs 61 are arranged radially around the central axis 55, for example, at equal intervals in the circumferential direction. In the first embodiment, as an example, twelve ribs 61 are arranged, but the number of ribs 61 is not limited to this. Each rib 61 is formed, for example, with the same length in the radial direction. When viewed from below, the radially inner ends of the ribs 61 are arranged to protrude (overlap) by the same length into the inner diameter portion 52 of the pipe portion 57.

[0027] FIG. 5 is an enlarged view of the main part of FIG.

[0028] The rib 61 has an extension 63 that protrudes from the vertical side 68, passing through the expanded diameter portion 54 and protruding into the inner diameter portion 52 of the tubular portion 57. The intersection of the oblique side 62 and the vertical side 68 of the rib 61 contacts the step that is the boundary between the inner circumferential surface 56 and the expanded diameter portion 54. In the first embodiment, this contact point between the rib 61 and the skirt portion 59 is also referred to as the second contact point Q. The length a of the rib 61 extending from the second contact point Q in the direction approaching the central axis 55 is preferably greater than the thickness t of the rib 61, but is not limited to this.

[0029] FIG. 6 is a perspective view of the suction pad 11 cut along a plane parallel to the central axis 55. As shown in FIG.

[0030] The rib 61 contacts at the second contact point Q with a stepped portion where the intersection of the hypotenuse portion 62 and the vertical side portion 68 is the boundary between the inner peripheral surface 56 and the enlarged diameter portion 54. The rib 61 projects horizontally (in the XY direction) radially inward from the second contact point Q where the bottom portion 64 is the end of the hypotenuse portion 62. This protruding portion projects radially inward as an extended portion 63, which is, for example, rectangular, from the vertical side portion 68 of the triangular portion 66. The protruding extended portion 63 passes through the enlarged diameter portion 54 and projects into the inner diameter portion 52 of the pipe portion 57 (see FIG. 5).

[0031] FIG. 7 is an enlarged perspective view of a main part of the suction pad 65 according to the comparative example.

[0032] Here, the suction pad 65 of the comparative example will be described. The rib 67 of the suction pad 65 has a triangular portion, but the vertical side portion 68X is formed as a flat surface along the central axis 55. That is, the rib 67 of the suction pad 65 does not have an extended portion 63 located closer to the central axis of the suction pad 11 than the second contact point Q. This is the same as the first rib of the suction pad shown in FIG. 4 of Patent Document 1.

[0033] FIG. 8A is a cross-sectional view of one side sandwiching the central axis 55 of the suction pad 11 cut along a plane including the central axis 55.

[0034] The suction pad 11 has the first distance L shorter than the second distance L2 (L < L2). The first distance L is the distance between at least one point (the first contact point P) where the rib 61 and the workpiece 17 contact and the central axis 55 of the suction pad 11. The second distance L2 is the distance between the second contact point Q where the rib 61 and the skirt portion 59 contact and the central axis 55. That is, the first distance L is shorter than the second distance L2 by the protruding length of the extended portion 63. The first distance L may be, for example, 1 / 2 or 1 / 3 of the second distance L2.

[0035] The rib 61 and the workpiece 17 may be in planar contact, and there may be multiple first contact points, one of which may be the first contact point P. The first contact point P is the point closest to the central axis 55 that comes into contact with the rib 67 when the workpiece 17 is present. In addition, although the above example illustrates that there is only one second contact point Q, the rib 61 and the skirt portion 59 may be in planar contact, and there may be multiple second contact points, and one of the multiple second contact points may be the second contact point Q. The second contact point Q may be the point closest to the central axis 55 among the points of contact between the rib 61 and the skirt portion 59.

[0036] Therefore, of the first contact points, the point closest to (closest to) the central axis 55 may be defined as the first contact point P. The first contact points exist on each of the multiple ribs 61, and therefore the first contact points P also exist on each of the multiple ribs 61. Similarly, of the second contact points, the point closest to (closest to) the central axis 55 may be defined as the second contact point Q. The second contact points exist on each of the multiple ribs 61, and therefore the second contact points Q also exist on each of the multiple ribs 61.

[0037] 8B is a diagram showing an example of the positional relationship between the first contact point P and the second contact point Q. FIG. 8B is a simplified view of the suction pad 11 as seen from below. In FIG. 8B, only one of the twelve ribs 61 is shown, and the other ribs 61 are not shown.

[0038] In the suction pad 11, the first contact point P is located within a line LQ that connects the second contact points Q of the multiple ribs 61. The line LQ may be an arc of a circle centered on the central axis 55 and having a radius equal to the second distance L2, or may be a side of a regular polygon that linearly connects the second contact points Q of the multiple ribs 61, or may be a line of some other shape that connects the second contact points Q.

[0039] In FIG. 8B , as an example, twelve ribs 61 are arranged radially along a horizontal plane around the central axis 55. The number of ribs 61 may be any number other than twelve. A first contact point P and a second contact point Q are shown for each rib 61. In FIG. 8B , the line LQ has a circular shape. The line LP connecting the first contact points P is also shown as a circle. In FIG. 8B , the line LQ and the line LP are arranged coaxially, meaning that all twelve first contact points P are located inside the line LQ. Of the twelve first contact points P, at least one first contact point P is located inside the line LQ. By locating at least one first contact point P inside the line LQ, the skirt portion 59 is less likely to turn up. Of the twelve first contact points P, preferably, three or more first contact points P are evenly spaced with respect to the central axis 55. Of the twelve first contact points P, three or more of the first contact points P are evenly arranged inside the line LQ with respect to the central axis 55, which makes it even more difficult for the skirt portion 59 to turn over. Furthermore, by having all of the first contact points P be evenly arranged inside the line LQ with respect to the central axis 55, it becomes even more difficult for the skirt portion 59 to turn over.

[0040] FIG. 9 is an explanatory diagram showing a suitable position of the notch 69 provided in the rib 61. As shown in FIG.

[0041] The rib 61 preferably has a notch 69 in the bottom portion 64. The notch 69 can be formed by cutting out a V-shape in the bottom portion 64. However, the shape of the notch is not limited to this, and it may be a part of a rectangle or a circle, etc.

[0042] The rib 61 has a third distance L3 that is longer than the second distance L2 (L3>L2). The third distance L3 is the distance between the notch 69 and the central axis 55. That is, the notch 69 is disposed in the base portion 64 radially outward of the second contact point Q. On the other hand, if the rib 61 has the notch 69 provided in the extension portion 63 radially inward of the second contact point Q (the notch on the right side in FIG. 9 ), the extension portion 63 becomes weak, and the force suppressing rotation (turning up) of the skirt portion 59 may be reduced, which is undesirable.

[0043] FIG. 10 is a perspective view of the suction pad 11 in which each of the ribs 61 is connected to another rib 61 on the side of the central axis 55.

[0044] The multiple ribs 61 arranged radially around the central axis 55 may have their sides (i.e., extensions 63) fixed to the central axis 55. In this case, each of the multiple ribs 61 may be connected to the other ribs 61 on the side of the central axis 55. If there are an even number of ribs 61, each pair of ribs 61 on either side of the central axis 55 can be connected in a straight line. Note that there may be an odd number of ribs 61, and for example, the ribs 61 may be arranged at regular angular intervals on a surface along the base portion 64. The extensions 63 of the ribs 61 are further extended to connect the extensions to each other. Furthermore, the height (length along the Z direction (height direction)) of each extension 63 of each rib 61 is shorter (shorter) than the height (length along the Z direction (height direction)) of the triangular portion 66. Therefore, in the suction pad 11, the extension portion 63 is separated in the Z direction from the step portion (second contact point Q) near the outlet of the expanded diameter portion 54 of the pipe portion 57, so that an increase in intake resistance can be suppressed.

[0045] FIG. 11 is a perspective view of the suction pad 11 in which each of the ribs 61 is connected to the central axis 55 side via a predetermined member 71 interposed therebetween.

[0046] The plurality of ribs 61 may be connected to each other via a predetermined member 71 disposed on the side of the central axis 55. In this case, the predetermined member 71 may be an annular body that is slightly smaller than the inner diameter portion 52 of the tubular portion 57. The annular body may be, for example, a circular ring, but is not limited to this and may also be polygonal. The predetermined member 71 may be the same member as the rib 61 or a different member. This leaves the suction pad 11 open near the opening of the expanded diameter portion 54 of the tubular portion 57, thereby reducing intake resistance compared to a configuration in which the central axis side of the extension portion 63 is connected and fixed.

[0047] Next, the operation of the above-described configuration will be described.

[0048] The suction pad 11 according to the first embodiment suctions a workpiece 17 and is connected to a vacuum generator 51. The suction pad 11 includes a skirt portion 59 and a plurality of ribs 61 formed inside the skirt portion 59 and in contact with the workpiece 17. Of the first contact points where the ribs 61 come into contact with the workpiece 17, a first contact point P closest to the central axis 55 of the suction pad 11 is located within a line LQ connecting second contact points Q closest to the central axis 55 among the second contact points where the plurality of ribs 61 come into contact with the skirt portion 59. Furthermore, for at least one of the plurality of ribs 61 of the suction pad 11, a first distance L may be shorter than a second distance L2. The first distance L is the distance between at least one of the first contact points where the rib 61 comes into contact with the workpiece 17 (for example, the first contact point P) and the central axis 55 of the suction pad 11. The second distance L2 is the distance between the center axis 55 and a second contact point Q where the rib 61 and the skirt portion 59 come into contact.

[0049] In the suction pad 11, the skirt portion 59 has a slope. The slope gradually becomes more inclined away from the central axis 55 of the suction pad 11 toward the suction opening of the skirt portion 59. A plurality of ribs 61 are provided on the slope inside the skirt portion 59, spaced apart in the circumferential direction. Each rib 61 has a triangular portion 66 including an oblique side portion 62 along the slope and a base portion 64 parallel to the suction opening surface.

[0050] As shown in FIG. 8A, the distance between the first contact point P of the rib 61, which comes into contact with the workpiece 17, and the central axis 55 of the suction pad 11 is the first distance L. The distance between the second contact point Q of the rib 61, which comes into contact with the skirt portion 59, and the central axis 55 is the second distance L2. The rib 61 is formed so that the first distance L is shorter than the second distance L2 (L <L2)。

[0051] In other words, the first contact point P between the rib 61 and the workpiece 17 of the suction pad 11 is located closer to the central axis of the suction pad 11 than the second contact point Q between the rib 61 and the skirt portion 59. The suction pad 11 has an extension 63 that protrudes closer to the central axis than the second contact point Q where the rib 61 and the skirt portion 59 come into contact.

[0052] The first contact point P and the second contact point Q appear in a cross section of the suction pad 11 cut along a plane including the central axis 55, and in the actual suction pad 11, they are lines or planes.

[0053] FIG. 12 is an explanatory diagram showing the process of suction of the workpiece 17 by the suction pad 11. As shown in FIG.

[0054] In the suction operation of the robot device 15, first, the suction pad 11 moves above the workpiece 17 (left diagram in FIG. 12), and then moves (approaches and descends) until the suction pad 11 touches the workpiece 17 (center diagram in FIG. 12). Then, in the robot device 15, the vacuum generator 51 generates negative pressure in the vacuum path inside the support pipe 53, the suction pad 11 suctions the workpiece 17, and the control device controls the position of the suction pad 11, causing the suction pad 11 to lift up the workpiece 17 (right diagram in FIG. 12).

[0055] FIG. 13 is an explanatory diagram of curling that occurs in the suction pad 65 according to the comparative example.

[0056] In the suction pad 65 of the comparative example, the skirt portion 59 sometimes turned up when it moved until it touched the workpiece 17. In the suction pad 65, the distance between at least one of the contact points (point PX) where the rib 61 and the workpiece 17 come into contact and the central axis 55 of the suction pad 11 is the same as the distance between the contact point (point QX) where the rib 61 and the skirt portion 59 come into contact and the central axis 55. In the suction pad 65, a rotation moment M is generated around point PX.

[0057] FIG. 14 is a schematic diagram illustrating the operation of a simplified suction pad 65 according to a comparative example when bending occurs.

[0058] The suction pad 65 of the comparative example does not have the extension 63 (see FIG. 8A) located closer to the central axis of the suction pad 11 than the second contact point Q (see FIG. 7).

[0059] The suction pad 65 of the comparative example comes into contact with the workpiece 17 at point PX, generating a rotational moment M with point PX as the fulcrum, which can cause the skirt portion 59 to turn over (flip up) in the direction of arrow M, resulting in a failure to suction. Here, the horizontal distance from the point of force (the point where the horizontal line passing through point PX intersects with the central axis 55) to point PX, which is the point of action, is the same as the second distance L2 described above. If the rotational moment due to force F here is M, then the moment at point PX can be calculated as M = F × L2.

[0060] FIG. 15 is a schematic diagram illustrating the operation of the suction pad 11 according to the first embodiment when bending occurs, with the suction pad 11 being simplified.

[0061] On the other hand, the suction pad 11 of the first embodiment has the extension portion 63, and therefore the horizontal distance from the force point to the first contact point P, which is the point of action, is the first distance L described above, which is shorter than the second distance L2. If the rotational moment due to the force F here is M2, the moment at the first contact point P can be calculated as M2 = F × L. That is, it can be seen that in the suction pad 11, L2 > L, and therefore M > M2.

[0062] Therefore, in the suction pad 11, the rotation moment is smaller than in a structure (see FIG. 7) that does not have the extension portion 63 as in Patent Document 1, and therefore the skirt portion 59 is less likely to turn up. In other words, with the suction pad 11, the positional relationship between the first contact point P, the second contact point Q, and the central axis 55 makes it possible to suppress turning up of the suction pad 11 when adsorbing the workpiece 17 to be adsorbed, thereby making it easier to successfully adsorb the workpiece 17.

[0063] Furthermore, in the suction pad 11, the rib 61 has a notch 69 at the bottom 64 of the rib 61, and the third distance L3, which is the distance between the notch 69 and the central axis 55, may be longer than the second distance L2.

[0064] In this suction pad 11, the rib 61 has a triangular portion 66. The triangular portion 66 has a hypotenuse portion 62 along the inclined surface and a base portion 64 parallel to the suction opening surface. As shown in FIG. 9 , the rib 61 has a notch 69 at the base portion 64. A third distance L3, which is the distance from the central axis 55 to the notch 69, is longer than the second distance L2. That is, the notch 69 is disposed radially outward from the joint (second contact point Q) between the rib 61 and the skirt portion 59, centered on the central axis 55. Note that it is sufficient that the third distance L3 is longer than the second distance L2 for at least one rib 61 among the multiple ribs 61. It is preferable that more ribs 61 have the third distance L3 longer than the second distance L2.

[0065] FIG. 16 is a diagram showing the operation of the suction pad 11 having the rib 61 without the notch 69 when suctioning a workpiece.

[0066] When the rib 61 does not have the notch 69, the rigidity of the rib 61 is high against deformation in the direction of tension due to the load of the workpiece 17. This high rigidity makes it difficult for the rib 61 to follow the shape of the deformed workpiece 17 (bag) compared to the rigidity when the rib 61 has the notch 69.

[0067] FIG. 17 is a diagram showing the operation of the suction pad 11 having the rib 61 with the notch 69 when suctioning a workpiece.

[0068] On the other hand, the rib 61 having the notch 69 in the bottom side 64 facilitates deformation in a direction that increases the downward slope (dip angle) of the oblique side 62 when the suction pad 11 is raised, for example, when the bag is deformed vertically. This allows the suction pad 11 to easily follow the shape of the bag, which is easily deformed, and makes it easier to successfully adsorb the workpiece 17 (bag).

[0069] In addition, as shown in FIG. 9, the rib 61 having the notch 69 in the bottom portion 64 has the notch 69 disposed radially outward from the second contact point Q about the central axis 55, thereby preventing a decrease in the strength of the extension portion 63 that contributes to preventing curling. That is, the suction pad 11 can prevent the extension portion 63 from being weakened due to the notch 69 being located radially inward from the second contact point Q (the notch on the right side in FIG. 9). The shape of the notch 69 is arbitrary, and for example, the cross section may be rectangular rather than triangular. The notch 69 is also formed in the circumferential direction.

[0070] In addition, in the suction pad 11, the plurality of ribs 61 may be arranged radially around the central axis 55, and the side of the central axis 55 may be fixed.

[0071] In this suction pad 11, the rib 61 is fixed on the side of the central axis 55. In this case, as shown in Fig. 10, the extension portion 63 of the rib 61 that protrudes toward the central axis 55 beyond the second contact point Q is no longer a free end. With the extension portion 63 fixed, an attractive force is generated in the rib 61 toward the center.

[0072] Here, the force attracting toward the center is a force that resists moment M2 (see FIG. 15). For example, when moment M2 occurs in a pair of ribs 61 that face each other across central axis 55, the ends on the central axis 55 side are displaced in a direction that separates them. The force attracting toward the center is a force that attracts the ends together against this separation between the ends. This attracting force may be a reaction force that resists the separation that occurs when the ends of ribs 61 are fixed. In this way, the suction pad 11 generates an attractive force between the ends of the ribs 61, making it more difficult for the ribs to turn over.

[0073] In addition, in the suction pad 11, each of the plurality of ribs 61 may be connected to another rib 61 on the side of the central axis 55.

[0074] In this suction pad 11, as shown in FIG. 10 , each of the multiple ribs 61 is connected to another rib 61 on the side of the central axis 55. The multiple ribs 61 are arranged radially around the central axis 55. The end of a rib 61 on the side of the central axis 55 is connected to the end of another rib 61 on the side of the central axis 55 at the position of the central axis 55. In this case, if there are, for example, an even number of ribs 61, each pair of ribs 61 on either side of the central axis 55 are connected in a straight line, and the ends of all the ribs 61 are connected at the central axis 55. If there are, for example, an odd number of ribs 61, the ends of all the ribs 61 are connected to each other while being arranged at, for example, a fixed angle.

[0075] In this suction pad 11, the ends of all of the suction pads 11 on the side of the central axis 55 can be fixed to each other. This allows the suction pads 11 to generate a force of attraction toward the center without using a predetermined member 71, making it more difficult for the suction pads 11 to turn over.

[0076] In addition, in this suction pad 11, the connection portion (radiating center portion) connecting the ends of the ribs 61 overlaps with the opening of the vacuum path inside the suction pad 11, which has the secondary effect of preventing foreign matter from entering the vacuum path.

[0077] In addition, in the suction pad 11, each of the plurality of ribs 61 may be connected via a predetermined member 71 arranged on the side of the central axis 55.

[0078] In this suction pad 11, the ends of the ribs 61 on the side of the central axis 55 are connected via a predetermined member 71, as shown in FIG. 11 . The predetermined member 71 can be, for example, a ring-shaped portion concentric with the opening of the vacuum path. In this case, the connecting portion (radial center portion) connecting the ribs 61 to each other is not formed at the position of the central axis 55, so the shape of the ribs 61 does not become complicated. Also, in this suction pad 11, the radial center portion does not overlap the opening of the vacuum path, so intake resistance to the vacuum path does not increase. As a result, the suction pad 11 is less likely to generate intake resistance and can generate an attractive force toward the center, making it more difficult for the suction pad 11 to turn over.

[0079] Next, a modification of the first embodiment will be described.

[0080] FIG. 18 is an explanatory diagram of the rib 61 provided with the bending prevention portion 73.

[0081] The rib 61 may be formed with a bending prevention portion 73 that fills the inside corner between the vertical side portion 68 and the extension portion 63. By providing the bending prevention portion 73 in the rib 61, the protruding tip of the extension portion 63 and the second contact point Q are connected by a right-angled triangular reinforcing plate. This increases the rigidity of the extension portion 63 of the rib 61 compared to when the bending prevention portion 73 is not provided. As a result, the rib 61 is less likely to deform due to the reaction force received from the workpiece 17, and a decrease in the anti-turning effect due to deformation can be suppressed.

[0082] 19 is an explanatory diagram of the rib 61 with the apex corner of the triangular portion 66 cut away. FIG. 20 is an explanatory diagram of the rib with the extension portion 63 cut away from the rib 61 shown in FIG.

[0083] The rib 61 may be formed in a trapezoidal shape by cutting the apex of the triangular portion 66 (see part C in FIG. 19) along a straight line parallel to the base portion 64.

[0084] In this case, a second distance L2A between the central axis 55 and a second contact point QA where the rib 61 and the skirt portion 59 come into contact is longer than a first distance LA between the central axis 55 and at least one of the first contact points (first contact point PA) where the rib 61 and the workpiece 17 come into contact. The rib 61 has an extension 63A. Therefore, as shown in FIG. 20, the distance between the central axis 55 and at least one of the first contact points (first contact point PB) where the rib 61 in FIG. 19, from which the extension 63A is cut off, comes into contact with the workpiece 17. The first distance LB is longer than the first distance LA. Therefore, the suction pad 11 having the rib 61 shown in FIG. 19 is less likely to turn over than the rib 61 shown in FIG. 20.

[0085] 19, the extension 63 remains, thereby suppressing curling, and the removal of the apex angle creates a gap (part C) between the skirt 59 and the extension 63. Therefore, in this case, deformation in a direction that increases the downward slope (dip angle) of the oblique side 62 (see FIG. 17) becomes easier. As a result, even with a rib 61 that does not have a notch 69, the suction pad 11 can easily follow the shape of the bag, which is easily deformed, and successfully adsorb the workpiece 17 (bag).

[0086] In this way, the suction pad 11 according to the first embodiment can suppress curling of the suction pad 11 when suctioning the workpiece 17 to be sucked, making it easier to successfully suck the workpiece 17.

[0087] (Outline of the embodiment) As a result, the present disclosure describes at least the following: Note that, in parentheses, examples of components corresponding to the above-described embodiments are given, but the present disclosure is not limited to these.

[0088] (Item 1) A suction pad (suction pad 11) that suctions a workpiece (workpiece 17) and is connected to a vacuum generator (vacuum generator 51), Skirt part (skirt part 59) and A plurality of ribs (ribs 61) formed inside the skirt portion and in contact with the workpiece; Equipped with Among the first contact points where the rib and the workpiece come into contact, a first contact point (first contact point P) closest to a central axis (central axis 55) of the suction pad is located within a line (line LQ) connecting second contact points (second contact point Q) closest to the central axis among second contact points where the plurality of ribs come into contact with the skirt portion. Suction pad.

[0089] As a result, compared to conventional suction pads, the first contact point is positioned inside the line connecting the second contact point closer to the central axis, shortening the first distance, reducing the rotational moment and making the skirt less likely to turn up. In other words, the positional relationship between the first contact point, the second contact point, and the central axis makes it possible to suppress turn-up of the suction pad when adsorbing a workpiece, making it easier to successfully adsorb the workpiece.

[0090] (Item 2) The rib has a notch (notch 69) at a bottom portion (bottom portion 64) of the rib, a distance (third distance L3) between the notch and the central axis is longer than a distance (second distance L2) between the second contact point and the central axis; Item 1. The suction pad according to item 1.

[0091] This allows the suction pad to follow the bag using the cutout portion when adsorbing a workpiece such as a bag, making it easier to hold the bag, and the positional relationship between the cutout portion, the second contact point, and the central axis makes it less likely for the suction pad to turn over.

[0092] (Item 3) The plurality of ribs are arranged radially around the central axis, and the side of the central axis is fixed. Item 3. The suction pad according to item 1 or 2.

[0093] As a result, the suction pad is fixed at the center of the rib, and a force acts toward the center, making it difficult for the suction pad to turn over.

[0094] (Item 4) Each of the plurality of ribs is connected to the other ribs on the side of the central axis. Item 3. The suction pad according to item 3.

[0095] This allows the suction pad to be fixed on the side of the central axis of the plurality of ribs without providing any additional members other than the ribs, and prevents the suction pad from curling up.

[0096] (Item 5) Each of the plurality of ribs is connected to a predetermined member arranged on the side of the central axis. Item 3. The suction pad according to item 3.

[0097] This prevents the shape of the ribs of the suction pad from becoming complicated, fixes the central axis side of the ribs, and makes it difficult for the suction pad to turn over.

[0098] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention. [Industrial Applicability]

[0099] The present disclosure is useful for a suction pad or the like that can prevent the suction pad from curling up when suctioning a workpiece to be sucked. [Explanation of symbols]

[0100] 11 Suction pad 17 Work 51 Vacuum Generator 55 Center axis 59 Skirt Club 61 Ribs 69 Notch 71 Prescribed parts L first distance L2 Second distance L3 Third distance P First contact point Q Second contact point

Claims

1. A suction pad that adsorbs a workpiece and is connected to a vacuum generator, The skirt part and A plurality of ribs formed inside the skirt portion and in contact with the workpiece; Equipped with Among first contact points where the rib comes into contact with the workpiece, a first contact point closest to a central axis of the suction pad is located within a line connecting second contact points, among second contact points where the plurality of ribs come into contact with the skirt portion, that are closest to the central axis. Suction pad.

2. The rib has a notch at a bottom portion of the rib, a distance between the notch and the central axis is longer than a distance between the second contact point and the central axis; The suction pad according to claim 1 .

3. The plurality of ribs are arranged radially around the central axis, and the side of the central axis is fixed. The suction pad according to claim 1 or 2.

4. Each of the plurality of ribs is connected to the other ribs on the side of the central axis. The suction pad according to claim 3 .

5. Each of the plurality of ribs is connected via a predetermined member arranged on the side of the central axis. The suction pad according to claim 3 .

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