suction cup

Abstract

A suction cup has a nonwoven fabric sheet (18) having a uniform thickness and shaped as a circular plate, and a ring-shaped holding body (28) that supports the nonwoven fabric sheet in a displaceable manner to a mounting adapter (12). A suction surface (20) is constituted by a flat surface of the nonwoven fabric sheet, the nonwoven fabric sheet has a non-air-permeable region (22) at an outer peripheral portion and an air-permeable region (24) other than the outer peripheral portion, and the non-air-permeable region has a higher density than the air-permeable region.

Description

Technical Field

[0001] This invention relates to a suction cup used in a vacuum adsorption device that uses negative pressure to attract workpieces. Background Technology

[0002] In the past, in vacuum adsorption devices that adsorb and transport sheet-shaped or plate-shaped workpieces, it is known to use adsorption pads made of porous materials to suppress wrinkles and deformation on the workpieces.

[0003] For example, Japanese Patent No. 5756956 discloses a vacuum adsorption device comprising: a main body having a port for supplying negative pressure fluid; a pad having a flat adsorption surface made of a porous material; and a retainer that holds the pad in a position to move freely relative to the main body. The pad has a main body portion and a thin-walled edge portion formed around the periphery of the main body portion, and the retainer is disposed between the edge portion of the pad and the main body.

[0004] According to the above-mentioned vacuum adsorption device, even when the workpiece is tilted relative to the adsorption surface of the pad, the adsorption surface of the pad can still come into contact with the workpiece.

[0005] Because the pad in the aforementioned vacuum adsorption device functions as a closed portion at the edge, the edge is crushed during the stamping process, creating a step between the main body and the edge. There is a concern that such a pad is prone to deformation near the step, making it difficult to maintain a flat adsorption surface.

[0006] Furthermore, since the pad in the aforementioned vacuum adsorption device allows for tilting, a predetermined space exists between the pad and the retaining plate mounted on the main body. Therefore, under high negative pressure, there is a concern that the pad may deform when tilted relative to the retaining plate, and the adsorption surface may not maintain a flat shape. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned technical problems.

[0008] This invention relates to a suction cup having an adsorption surface capable of adhering tightly to a workpiece. It comprises: a mounting adapter mounted to a vacuum generating device; a nonwoven fabric sheet having a uniform thickness and shaped as a circular plate; and an annular retainer supporting the nonwoven fabric sheet in a displaceable manner on the mounting adapter. The adsorption surface is formed by a flat surface of the nonwoven fabric sheet, which has a non-ventilated outer periphery and a ventilated area excluding the outer periphery. The density of the non-ventilated area is higher than that of the ventilated area.

[0009] According to the suction cup of the present invention, since the nonwoven fabric sheet has a uniform thickness, the nonwoven fabric sheet is difficult to deform, and the flat shape of the adsorption surface is maintained. In addition, by adjusting the density of the nonwoven fabric sheet, a non-ventilated area on the outer periphery and a ventilated area other than the outer periphery can be easily formed.

[0010] The above-described objectives, features, and advantages are readily understood from the following description of the embodiments, which are illustrated with reference to the accompanying drawings. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of the suction cup according to the first embodiment of the present invention.

[0012] Figure 2 It is Figure 1 The suction cup is unfolded into a diagram of the component unit.

[0013] Figure 3 yes Figure 1 A top view of the nonwoven sheet of suction cups.

[0014] Figure 4 yes Figure 1 A top view of the suction cup retaining plate.

[0015] Figure 5 It means Figure 1 The diagram shows a situation where the suction cup's retaining plate moves without changing its posture to adhere to and hold the workpiece.

[0016] Figure 6 It means Figure 1 The diagram shows a situation where the suction cup's retaining plate is tilted to attract and hold the workpiece.

[0017] Figure 7 This is a cross-sectional view of the suction cup according to the second embodiment of the present invention.

[0018] Figure 8 It is Figure 7 The suction cup is unfolded into a diagram of the component unit. Detailed Implementation

[0019] (First Implementation)

[0020] Reference Figures 1-6 The suction cup 10 according to the first embodiment of the present invention will be described below. In the following description, when terms relating to up, down, left, and right directions are used, for convenience, they refer to the directions shown in the drawings and do not limit the actual arrangement of components, etc.

[0021] like Figure 1 and Figure 2As shown, the suction cup 10 includes a mounting adapter 12, a non-woven fabric sheet 18, a retaining plate 26, a retaining body 28, and a damper 32. The mounting adapter 12 is made of a metal material such as aluminum alloy and is configured in a disc shape. The mounting adapter 12 has a negative pressure supply passage 14 that runs through the center of the mounting adapter 12 from top to bottom, and is mounted on a vacuum generating device (not shown). The lower part of the mounting adapter 12 has a stepped portion 16 for mounting the retaining body 28. Furthermore, reference numeral 12a indicates the bolt hole for mounting the mounting adapter 12 to the vacuum generating device.

[0022] The nonwoven sheet 18 contains resin fibers and conductive fillers. The nonwoven sheet 18 is formed into a disc shape and has a uniform thickness. The flat lower surface of the nonwoven sheet 18 constitutes an adsorption surface 20 that can tightly adhere to sheet-like or plate-like workpieces. Figure 3 As shown, the nonwoven sheet 18 has a non-ventilated outer periphery 22 and a ventilated outer periphery 24. The density of the non-ventilated area 22 is higher than that of the ventilated area 24.

[0023] The retaining plate 26 is made of a metal material such as stainless steel and is configured as a circular plate. The outer diameter of the retaining plate 26 is the same as the outer diameter of the nonwoven fabric sheet 18. The retaining plate 26 is bonded to the nonwoven fabric sheet 18, for example, using conductive double-sided tape. Figure 4 As shown, the retaining plate 26 has a first hole 16a at its center that matches the negative pressure supply passage 14 of the mounting adapter 12. The retaining plate 26 has a plurality of arc-shaped second holes 26b surrounding the first hole 26a. The plurality of second holes 26b are formed at locations corresponding to the ventilation area 24 of the nonwoven sheet 18.

[0024] The nonwoven sheet 18 has a uniform thickness and a stepless shape, making it difficult to deform. Furthermore, since the nonwoven sheet 18 is supported by a highly rigid retaining plate 26, it will not deform even under large negative pressure (high vacuum pressure), and the flat shape of the adsorption surface 20 is reliably maintained. Additionally, since the retaining plate 26 has multiple second holes 26b corresponding to the ventilation area 24 of the nonwoven sheet 18, the retaining plate 26 does not impede the ventilation of the nonwoven sheet 18.

[0025] The retainer 28 is a porous rubber sponge formed by foaming a rubber material such as chloroprene rubber with conductive fillers such as carbon and metal. The retainer 28 contains multiple independent air bubbles and is not breathable. The retainer 28 is formed in a ring shape and disposed between the mounting adapter 12 and the retaining plate 26. The retainer 28 is mounted on the stepped portion 16 of the mounting adapter 12 and protrudes downward from the mounting adapter 12. The nonwoven sheet 18 and the retaining plate 26 are supported on the mounting adapter 12 in a displaceable manner by the retainer 28.

[0026] The retainer 28 has a notch 30 around its outer peripheral surface. Specifically, the retainer 28 has a first flange 28b extending radially outward from the upper part of the main body 28a and a second flange 28c extending radially outward from the lower part of the main body 28a. The upper surface of the retainer 28 engages with the stepped surface 16a in the stepped portion 16 of the mounting adapter 12, and the lower surface of the retainer 28 engages with the upper surface of the outer peripheral portion of the retaining plate 26.

[0027] The damper 32 is made of rubber material such as NBR and is formed into a ring shape. The damper 32 is mounted on the lower part of the mounting adapter 12 and protrudes slightly downward from the lower surface of the mounting adapter 12. The damper 32 is positioned opposite the upper surface of the retaining plate 26 with a predetermined gap. The damper 32 abuts against the retaining plate 26 when the retaining plate 26 is displaced upward.

[0028] The retainer 28 with its independent bubble structure is preferably used with a crush rate of 30% or less. In other words, the retainer 28 is preferably used with a compression rate of 30% or less within the range of elastic deformation. If the crush rate significantly exceeds 30% during repeated use, the bubbles inside the retainer 28 will rupture, and the cushioning and non-breathability of the retainer 28 will be compromised.

[0029] Therefore, when the height (thickness in the vertical direction) of the main body 28a of the retainer 28 is set as H, and the vertical distance from the stepped surface 16a of the mounting adapter 12 to the protruding end of the damper 32 is set as L, the value of (H-L) / H is preferably 0.3 or less. This maintains the desired cushioning and airtightness of the retainer 28 for a longer period. Furthermore, the cushioning of the retainer 28 depends on the main body 28a; the first flange 28b and the second flange 28c do not contribute to the cushioning of the retainer 28.

[0030] The upper surface of the retainer 28 is engaged with the stepped surface 16a of the mounting adapter 12 using conductive double-sided tape (not shown). The lower surface of the retainer 28 is engaged with the upper surface of the outer periphery of the retaining plate 26, which is engaged with the non-woven fabric sheet 18, using conductive double-sided tape (not shown). Specifically, with double-sided tape between the upper surface of the retainer 28 and the stepped surface 16a of the mounting adapter 12, and with double-sided tape between the lower surface of the retainer 28 and the upper surface of the retaining plate 26, a rigid clamp (not shown) is inserted into the notched groove 30 of the retainer 28.

[0031] Subsequently, the first flange 28b of the retainer 28 is clamped between the mounting adapter 12 and the clamp, and the retainer 28, the double-sided tape, and the mounting adapter 12 are pressed together. Then, the second flange 28c of the retainer 28 is clamped between the retaining plate 26 and the clamp, and the retainer 28, the double-sided tape, and the retaining plate 26 are pressed together. Furthermore, the order of these two pressing processes can be reversed.

[0032] Through the aforementioned crimping process, the first flange portion 28b of the retainer 28 is significantly crushed while adhering tightly to the double-sided tape. Similarly, the second flange portion 28c of the retainer 28 is significantly crushed while adhering tightly to the double-sided tape. Therefore, the double-sided tape reliably connects the retainer 28 to the mounting adapter 12 and reliably connects the retainer 28 to the retaining plate 26.

[0033] Next, refer to Figure 5 and Figure 6 This section explains the function of a plate-shaped workpiece W, such as a glass substrate, being adsorbed and held by a suction cup 10. The workpiece W has a size larger than the adsorption surface 20 of the suction cup 10, and it is assumed that adsorption and holding are achieved using multiple suction cups 10. Hereinafter, the structure of mounting multiple suction cups 10 on a vacuum generating device (not shown) will be referred to as a "vacuum adsorption device".

[0034] The vacuum adsorption device operates to supply negative pressure (vacuum pressure) to the negative pressure supply passage 14 of the suction cup 10, causing the vacuum adsorption device to move and the suction cup 10 to approach the workpiece W. When negative pressure is supplied to the negative pressure supply passage 14, the negative pressure acts on the nonwoven sheet 18 through the first hole 26a and the second hole 26b of the holding plate 26. This negative pressure further acts on the workpiece W opposite the lower surface of the nonwoven sheet 18 through the ventilation area 24 of the nonwoven sheet 18.

[0035] When the workpiece W is relatively light, even without pressing the suction cup 10 against it, the workpiece W will shift upwards (lift) and come into close contact with the suction surface 20 of the suction cup 10. When the workpiece W is relatively heavy, pressing the suction cup 10 against it will cause the suction surface 20 of the suction cup 10 to come into close contact with the workpiece W.

[0036] Once the workpiece W is firmly attached to the suction surface 20 of the suction cup 10, the pressure difference between the negative pressure acting on the upper surface of the workpiece W and the atmospheric pressure acting on the lower surface of the workpiece W increases sharply. The workpiece W pushes up the nonwoven sheet 18 and the retaining plate 26 through this pressure difference, displacing upwards while crushing the retaining body 28. The displacement of the workpiece W stops when the retaining plate 26 comes into contact with the damper 32. Thus, the workpiece W is adsorbed and held in a stable state by the suction cup 10. The impact of the workpiece W being lifted is absorbed by crushing the retaining body 28 and by the contact between the retaining plate 26 and the damper 32.

[0037] Because the nonwoven sheet 18 has a non-ventilated area 22 on its outer periphery, and the retainer 28 with its independent bubble structure is not ventilated, no vacuum leakage will occur. Furthermore, the joints between the retainer 28 and the mounting adapter 12, the joints between the retainer 28 and the retaining plate 26, and the joints between the retaining plate 26 and the nonwoven sheet 18 are sealed in a manner that prevents vacuum leakage.

[0038] Figure 5 This describes the situation where the nonwoven fabric sheet 18 and the retaining plate 26 move upwards without changing their posture to adsorb and hold the workpiece W. When the upper surface of the highly rigid workpiece W has a high-precision plane, and multiple suction cups 10 are precisely mounted on the vacuum generator, the workpiece W is held at all suction cups 10 with... Figure 5 The state shown is adsorbed and maintained.

[0039] In contrast, if a portion of the multiple suction cups 10 is not installed in the vacuum generating device in the correct orientation (if the installation error exceeds the specified value), the workpiece W is positioned at a portion of the suction cup 10. Figure 6 The state shown is that the workpiece is adsorbed and held. Similarly, even when the upper surface of the highly rigid workpiece W is not flat, the workpiece W is held at a portion of the suction cup 10. Figure 6 The state shown is adsorbed and maintained. As a result, the workpiece W can be in close contact with the adsorption surfaces 20 of all the suction cups 10.

[0040] like Figure 6 As shown, the nonwoven sheet 18 and the retaining plate 26 are inclined relative to the mounting adapter 12, and the workpiece W is in close contact with the inclined nonwoven sheet 18. The crushing amount of the retaining body 28 is the largest at the right end, which is the diameter direction, and the crushing amount of the retaining body 28 is the smallest at the left end, which is the other diameter direction. Furthermore, in the initial description of the adsorption and holding action, the suction cup 10 is brought close to the workpiece W while a negative pressure is supplied to the negative pressure supply passage 14 of the suction cup 10. However, it is also possible to supply negative pressure to the negative pressure supply passage 14 after the suction cup 10 is pressed against the workpiece W.

[0041] According to the suction cup 10 of this embodiment, since the nonwoven sheet 18 has a uniform thickness, the nonwoven sheet 18 is difficult to deform, and the planar shape of the adsorption surface 20 is maintained. Moreover, since the nonwoven sheet 18 is supported by the highly rigid retaining plate 26, the nonwoven sheet 18 will not deform even if a large negative pressure (high vacuum pressure) is applied to it.

[0042] Furthermore, by adjusting the density of the nonwoven sheet 18, a non-ventilated area 22 on the outer periphery and a ventilated area 24 outside the outer periphery can be easily formed. Since the nonwoven sheet 18 has a non-ventilated area 22 and the retainer 28 is not ventilated, vacuum leakage will not occur.

[0043] Furthermore, since the nonwoven sheet 18 and the retaining plate 26 are supported on the mounting adapter 12 in a displaceable manner by the retainer 28 with its independent bubble structure, the impact when the workpiece W is lifted is absorbed. Moreover, even if there is a specified error in the installation of the suction cup 10 with the vacuum generating device, the workpiece W is reliably in close contact with the adsorption surface 20 of the suction cup 10.

[0044] Furthermore, since the retainer 28 has a notch 30 for clamp insertion, the crushing rate of the main body 28a during use can be optimized, and the retainer 28 can be reliably joined by double-sided tape. In addition, since the non-woven sheet 18, the retainer 28, and the double-sided tape are conductive, static electricity generated during the attraction and retention of the workpiece W can be released to the outside.

[0045] (Second Implementation)

[0046] Next, refer to Figure 7 and Figure 8 The suction cup 40 according to the second embodiment of the present invention will be described. Furthermore, in the suction cup 40 according to the second embodiment, structural elements that are the same as or equivalent to those in the suction cup 10 described above are marked with the same reference numerals, and detailed descriptions are omitted. Figure 7 and Figure 8 As shown, the suction cup 40 includes a mounting adapter 12, a non-woven fabric sheet 18, a retaining plate 42, and a retaining body 28.

[0047] The retaining plate 42 is made of a metal material such as stainless steel and is configured as a circular plate. The retaining plate 42 is joined to the mounting adapter 12, for example, using conductive double-sided tape. The retaining plate 42 has a first hole 42a at its center that matches the negative pressure supply passage 14 of the mounting adapter 12. The retaining plate 42 has a plurality of arc-shaped second holes 42b surrounding the first hole 42a. The plurality of second holes 42b are formed at locations corresponding to the ventilation area 24 of the nonwoven sheet 18. The retaining plate 42 and the nonwoven sheet 18 are positioned opposite each other at predetermined intervals. When the nonwoven sheet 18 is displaced upwards, the nonwoven sheet 18 abuts against the retaining plate 42.

[0048] The retainer 28, which serves as a rubber sponge body, contains multiple independent air bubbles and is non-breathable. The retainer 28 is ring-shaped and positioned between the mounting adapter 12 and the nonwoven sheet 18. The outer diameter of the retainer 28 matches the outer diameter of the nonwoven sheet 18. A retaining plate 42 is positioned inside the retainer 28. The retainer 28 is mounted on the step portion 16 of the mounting adapter 12 and protrudes downward beyond the retaining plate 42. The nonwoven sheet 18 is supported on the mounting adapter 12 in a displaceable manner by the retainer 28.

[0049] The retainer 28 has a notch 30 around its outer peripheral surface. The first flange 28b of the retainer 28 engages with the stepped surface 16a of the mounting adapter 12. The second flange 28c of the retainer 28 engages with the upper surface of the non-ventilated area 22 of the nonwoven sheet 18.

[0050] The retainer 28 with its independent bubble structure is preferably used with a crush rate of 30% or less. Therefore, when the height of the main body 28a of the retainer 28 is set to H, and the vertical distance from the stepped surface 16a of the mounting adapter 12 to the lower surface of the retaining plate 42 is set to L', the value of (H-L') / H is preferably 0.3 or less. This maintains the desired cushioning and non-breathability of the retainer 28 for a longer period of time.

[0051] The upper surface of the retainer 28 is bonded to the stepped surface 16a of the mounting adapter 12 using conductive double-sided tape. The lower surface of the retainer 28 is bonded to the upper surface of the nonwoven sheet 18 using conductive double-sided tape. Specifically, with double-sided tape between the upper surface of the retainer 28 and the stepped surface 16a of the mounting adapter 12, and with double-sided tape between the lower surface of the retainer 28 and the upper surface of the nonwoven sheet 18, the rigid clamp is inserted into the notched groove 30 of the retainer 28.

[0052] Subsequently, the first flange 28b of the retainer 28 is clamped between the mounting adapter 12 and the clamp, and the retainer 28, the double-sided tape, and the mounting adapter 12 are pressed together. Then, the second flange 28c of the retainer 28 is clamped between the nonwoven sheet 18 and the clamp, and the retainer 28, the double-sided tape, and the nonwoven sheet 18 are pressed together. Furthermore, the order of these two pressing processes can also be reversed.

[0053] Through the aforementioned crimping process, the first flange portion 28b of the retainer 28 is significantly crushed while adhering tightly to the double-sided tape. Similarly, the second flange portion 28c of the retainer 28 is significantly crushed while adhering tightly to the double-sided tape. Therefore, the double-sided tape reliably bonds the retainer 28 to the mounting adapter 12 and reliably bonds the retainer 28 to the non-woven fabric sheet 18.

[0054] When negative pressure is supplied to the negative pressure supply passage 14, the negative pressure acts on the upper surface of the nonwoven sheet 18 through the first hole 42a and the second hole 42b of the retaining plate 42. The negative pressure further acts on the workpiece W opposite the lower surface of the nonwoven sheet 18 through the ventilation area 24 of the nonwoven sheet 18.

[0055] Once the workpiece W is firmly attached to the suction surface 20 of the suction cup 10, the pressure difference between the negative pressure acting on the upper surface of the workpiece W and the atmospheric pressure acting on the lower surface of the workpiece W increases sharply. The workpiece W pushes up the nonwoven sheet 18 through this pressure difference, displacing upwards while crushing the retainer 28. The displacement of the workpiece W stops when the nonwoven sheet 18 comes into contact with the retaining plate 42. Because the nonwoven sheet 18 in contact with the retaining plate 42 is supported by the highly rigid retaining plate 42, the nonwoven sheet 18 will not deform even when a large negative pressure is applied. The impact of the workpiece W being lifted is absorbed by the crushing retainer 28.

[0056] The suction cups involved in this invention are not limited to the embodiments described above, and various structures can be adopted without departing from the spirit of this invention.

Claims

1. A suction cup (10, 40) having an adsorption surface (20) capable of adhering tightly to a workpiece, characterized in that, have: Mounting adapter (12), which is mounted on the vacuum generator; Nonwoven sheet (18), the nonwoven sheet having a uniform thickness and being formed into a circular plate shape; as well as A ring-shaped retainer (28) supports the nonwoven sheet in a displaceable manner on the mounting adapter. The adsorption surface is formed by the flat surface of the nonwoven sheet, which has a non-ventilated area (22) on the outer periphery and a ventilated area (24) other than the outer periphery, wherein the density of the non-ventilated area is higher than the density of the ventilated area.

2. The suction cup according to claim 1, characterized in that, The retainer has an independent bubble structure.

3. The suction cup according to claim 2, characterized in that, The retaining plate (26) is bonded to the nonwoven sheet.

4. The suction cup according to claim 3, characterized in that, The retainer has a cutout groove (30) for clamp insertion, the cutout groove surrounding the outer peripheral surface of the retainer, the retainer engaging with the mounting adapter using double-sided tape, and the retainer engaging with the retaining plate using double-sided tape.

5. The suction cup according to claim 4, characterized in that, It includes a damper (32) which is fitted to the mounting adapter and is capable of abutting against the retaining plate.

6. The suction cup according to claim 5, characterized in that, When the height of the main body of the retainer is set to H, and the distance from the stepped surface of the mounting adapter that engages with the retainer to the protruding end of the damper is set to L, the value of (H-L) / H is 0.3 or less.

7. The suction cup according to claim 2, characterized in that, The retaining plate (42) engages with the mounting adapter.

8. The suction cup according to claim 7, characterized in that, The retainer has a cutout groove for clamp insertion, the cutout groove surrounding the outer peripheral surface of the retainer, the retainer is engaged with the mounting adapter using double-sided tape, and the retainer is engaged with the non-woven sheet using double-sided tape.

9. The suction cup according to claim 8, characterized in that, When the height of the main body of the retainer is set to H, and the distance from the stepped surface of the mounting adapter that engages with the retainer to the retaining plate is set to L', the value of (H-L') / H is 0.3 or less.

10. The suction cup according to claim 2, characterized in that, The nonwoven sheet and the retainer are conductive.

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