Bellows-like member and method for manufacturing bellows-like member

Abstract

A bellows-like member 10 according to the present disclosure has a plurality of crest parts 11 projecting radially outward and a plurality of trough parts 12 recessed radially inward, which are axially arranged side by side. The crest parts 11 and the trough parts 12 are formed by joining at least two sheet-like members 20 together. The bellows-like member 10 has first sections 10A and a second section 10B, which are axially aligned and connected together. The first section 10A and the second section 10B are each formed by at least one of the sheet-like members 20. The first sections 10A have stretchability lower than that of the second section 10B.

Description

Accordion-shaped member and method of manufacturing the same

[0001] FIELD The present disclosure relates to a bellows-like member and a method for manufacturing the bellows-like member.

[0002] A conventional SCARA robot is described in Japanese Patent No. 5792988 (Patent Document 1). This SCARA robot includes a base, a first arm, a second arm, an elevation and rotation drive device provided on the second arm, and upper and lower bellows-shaped members provided above and below the elevation and rotation drive device. The upper and lower bellows-shaped members are made of expandable and contractible members formed from urethane resin in a bellows shape.

[0003] Patent No. 5792988

[0004] The above-described bellows-shaped member deforms and fatigues each time the lifting and rotation drive device is operated. Parts of the bellows-shaped member that are prone to localized stress, such as the portion near the fixed portion in Patent Document 1, are particularly prone to accumulating fatigue and are prone to early breakage. Therefore, to extend the life of the bellows-shaped member, it is preferable to provide higher rigidity to the portions of the bellows-shaped member that are prone to localized stress than to other portions, depending on the manner in which the bellows-shaped member is used.

[0005] The present disclosure was completed in light of the above circumstances, and an object of the present disclosure is to provide a bellows-shaped member having portions with different stretchability.

[0006] The accordion-shaped member of the present disclosure has a plurality of peaks that protrude radially outward and a plurality of valleys that recess radially inward, arranged side by side in the axial direction, and the peaks and valleys are each formed by joining at least two sheet-like members, and has a first portion and a second portion that are connected in the axial direction, and the first portion and the second portion are each formed from at least one of the sheet-like members, and the first portion has less elasticity than the second portion.

[0007] In addition, the method for manufacturing a bellows-shaped member disclosed herein includes a sheet forming process for forming a plurality of flexible sheet-shaped members each having through holes, and a sheet joining process for joining the outer edge portions of the sheet-shaped members to form peak portions and joining the hole edge portions of the through holes to form valley portions, wherein the sheet joining process forms a first portion including at least one of the sheet-shaped members and a second portion that is axially connected to the first portion and includes at least one of the sheet-shaped members, and the first portion is formed so as to have less elasticity in the axial direction compared to the second portion.

[0008] According to the present disclosure, it is possible to provide a bellows-shaped member having portions with different stretchability.

[0009] FIG. 1 is a side view of a bellows-shaped member according to a first embodiment. FIG. 2 is a plan view of the bellows-shaped member. FIG. 3 is an enlarged cross-sectional view of the bellows-shaped member. FIG. 4 is a perspective view of a sheet-shaped member. FIG. 5 is an explanatory diagram showing the joining of sheet-shaped members. FIG. 6 is a side view of a bellows-shaped member according to a second embodiment. FIG. 7 is a side view of a bellows-shaped member according to a third embodiment. FIG. 8 is a side view of a conventional bellows-shaped member, illustrating the bellows-shaped member when tensioned and compressed. FIG. 9 is a side view of a bellows-shaped member according to a fourth embodiment, illustrating the bellows-shaped member when tensioned and compressed. FIG. 10 is a cross-sectional view of a part of a robot including a bellows-shaped member according to a fifth embodiment. FIG. 11 is an enlarged cross-sectional view of a bellows-shaped member according to a sixth embodiment. FIG. 12 is an enlarged cross-sectional view of a bellows-shaped member according to another embodiment, in which the first and second sheet-shaped members are made of different materials. FIG. 13 is a perspective view of a bellows-shaped member according to another embodiment, including a fixing portion different from those of the first to sixth embodiments. Fig. 14 is a perspective view of a bellows-shaped member according to another embodiment, the bellows-shaped member having a rectangular shape when viewed from the axial direction. Fig. 15 is a side view of the bellows-shaped member shown in Fig. 14. Fig. 16 is an enlarged cross-sectional view of the bellows-shaped member shown in Fig. 14.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be described below. (1) A bellows-shaped member of the present disclosure includes a plurality of peaks protruding radially outward and a plurality of valleys recessed radially inward, arranged side by side in the axial direction, each of the peaks and valleys being formed by joining at least two sheet-shaped members, the bellows-shaped member having a first portion and a second portion connected in the axial direction, each of the first portion and the second portion being formed from at least one of the sheet-shaped members, and the first portion having less elasticity than the second portion.

[0011] With this configuration, it is possible to provide a bellows-shaped member having a first portion and a second portion with different elasticity. For example, by taking into consideration the manner in which the bellows-shaped member is used, and designing the portion that is more likely to be subjected to stress as the first portion, it is possible to more easily prevent damage to the bellows-shaped member.

[0012] (2) In the above (1), when the dimension from the center in the radial direction to the peak portion is defined as the outer diameter, the dimension from the center in the radial direction to the valley portion is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the inner / outer diameter difference, it is preferable that the inner / outer diameter difference of the first portion is smaller than the inner / outer diameter difference of the second portion.

[0013] With this configuration, the difference between the inner and outer diameters allows the first portion to have less stretchability than the second portion.

[0014] (3) In the above (1), it is preferable that the sheet-like member constituting the first part is a first sheet-like member, the sheet-like member constituting the second part is a second sheet-like member, and the first sheet-like member is formed by stacking two or more of the second sheet-like members.

[0015] (4) In the above (1), it is preferable that the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the thickness of the first sheet-like member is greater than the thickness of the second sheet-like member.

[0016] With this configuration, the difference in thickness of the sheet-like material constituting each portion allows the first portion to have less stretchability than the second portion.

[0017] (5) In the above (1), it is preferable that the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the hardness of the first sheet-like member is higher than the hardness of the second sheet-like member.

[0018] With this configuration, the stretchability of the first portion can be made smaller than that of the second portion due to the difference in hardness of the sheet-like members that make up each portion.

[0019] (6) In any one of the above (1) to (5), it is preferable that the first portion is disposed near an end of the bellows-shaped member.

[0020] With this configuration, it is possible to increase the rigidity of the bellows-shaped member in the vicinity of the end portion where stress tends to be concentrated.

[0021] (7) In any one of (1) to (5) above, it is preferable that the axial direction and the vertical direction are arranged to approximately coincide with each other, and the first portion includes a plurality of the peaks and a plurality of the valleys, and constitutes the upper portion of the accordion-shaped member.

[0022] With this configuration, by increasing the rigidity of the upper part of the bellows-shaped member, which is more likely to be subjected to its own weight, the lower part of the bellows-shaped member is less likely to slacken.

[0023] (8) In the above (2), it is preferable that the first portion includes a plurality of the peaks and a plurality of the valleys, and the inner diameter of the first portion is larger than the inner diameter of the second portion.

[0024] With this configuration, for example, when the accordion-shaped member is used to cover the accommodated portion, the part of the accommodated portion that has a larger radial dimension can be accommodated inside the first part of the accordion-shaped member, thereby suppressing interference between the accordion-shaped member and the accommodated portion.

[0025] (9) The method for manufacturing a bellows-shaped member of the present disclosure includes a sheet forming process for forming a plurality of flexible sheet-shaped members each having through holes, and a sheet joining process for joining the outer edges of the sheet-shaped members to form peaks and joining the edge portions of the through holes to form valleys, wherein the sheet joining process forms a first portion including at least one of the sheet-shaped members and a second portion axially connected to the first portion and including at least one of the sheet-shaped members, and the first portion is formed to have less elasticity in the axial direction than the second portion.

[0026] According to this method for manufacturing a bellows-shaped member, a bellows-shaped member having a first portion and a second portion with different stretchability can be provided by joining sheet-shaped members.

[0027] (10) In the above (9), in the sheet joining process, if the dimension from the center to the peak in a radial direction perpendicular to the axial direction is defined as the outer diameter, the dimension from the center to the valley in the radial direction is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the inner / outer diameter difference, it is preferable that the inner / outer diameter difference of the first portion is formed to be smaller than the inner / outer diameter difference of the second portion.

[0028] According to this method for manufacturing the accordion-shaped member, the difference between the inner and outer diameters makes it possible to make the first portion less stretchable than the second portion.

[0029] (11) In the above (9), it is preferable that the sheet-like member constituting the first part is a first sheet-like member, the sheet-like member constituting the second part is a second sheet-like member, and the first sheet-like member is formed by stacking two or more of the second sheet-like members.

[0030] (12) In the above (9), it is preferable that the sheet-like member constituting the first part is a first sheet-like member, the sheet-like member constituting the second part is a second sheet-like member, and the thickness of the first sheet-like member is greater than the thickness of the second sheet-like member.

[0031] According to this method for manufacturing the accordion-shaped member, the difference in thickness of the sheet-shaped member constituting each portion makes it possible to make the stretchability of the first portion smaller than that of the second portion.

[0032] (13) In the above (9), it is preferable that the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the hardness of the first sheet-like member is higher than the hardness of the second sheet-like member.

[0033] According to this method for manufacturing the accordion-shaped member, the stretchability of the first portion can be made smaller than that of the second portion by the difference in hardness of the sheet-shaped members constituting each portion.

[0034] [Details of the Embodiments of the Present Disclosure] The following describes embodiments of the present disclosure. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, when multiple identical components are used, only some of the components may be designated by reference numerals, and the reference numerals of other components may be omitted.

[0035] [Embodiment 1] Embodiment 1 of the present disclosure will be described with reference to FIGS. 1 to 5. As shown in FIG. 2, a bellows-shaped member 10 of this embodiment is cylindrical and has an opening 16. The opening direction of the bellows-shaped member 10 is the axial direction. Note that, although the vertical direction is described as the axial direction in this specification, in actual use, the axial direction of the bellows-shaped member 10 may not coincide with the vertical direction. The bellows-shaped member 10 has, for example, a circular shape when viewed from the axial direction. The bellows-shaped member 10 is configured to be expandable and contractible in the axial direction. The bellows-shaped member 10 of this embodiment is used, for example, to cover an operating shaft of a robot, machine tool, or the like. As will be described in detail later, the bellows-shaped member 10 is formed by joining multiple sheet-shaped members 20 (see FIG. 4).

[0036] As shown in FIG. 1 , the bellows-shaped member 10 has a plurality of peaks 11 and a plurality of valleys 12, and the peaks 11 and valleys 12 are alternately arranged in the axial direction. Here, the axis passing through the center of the bellows-shaped member 10 when viewed from the axial direction and extending in the axial direction is defined as the central axis CA. The direction passing through the central axis CA and perpendicular to the axial direction is defined as the radial direction. The radial direction away from the central axis CA is defined as the radial outward direction, and the radial direction approaching the central axis CA is defined as the radial inward direction. The peaks 11 are convex and protrude radially outward. The valleys 12 are concave and recessed radially inward. The peaks 11 and valleys 12 are each formed by joining two sheet-like members 20 (see FIG. 5 ).

[0037] The accordion-shaped member 10 has a main body 13, two fixing portions 14 arranged at both axial ends of the accordion-shaped member 10, and a connecting portion 15 connecting the fixing portions 14 to the ends of the main body 13. The main body 13 of the accordion-shaped member 10 has two first portions 10A and one second portion 10B. The depth of the valleys 12 in the first portions 10A is shallower than that in the second portion 10B. The first portions 10A and the second portions 10B are connected in the axial direction. The two first portions 10A are connected to both axial ends of the second portion 10B. The fixing portions 14 are, for example, cylindrical. The fixing portions 14 are fixed to a robot. The fixing portions 14 are fixed to, for example, a bearing member, a housing, etc. The connecting portion 15 connects the fixing portions 14 to the first portions 10A.

[0038] As shown in Figure 4, the sheet-like member 20 has a thin shape. The sheet-like member 20 is flexible and elastically deformable. The sheet-like member 20 is formed, for example, from a urethane sheet. A through-hole 21 is provided in the approximate center of the sheet-like member 20. The sheet-like member 20 and its through-hole 21 are, for example, circular when viewed in the thickness direction of the sheet-like member 20. The sheet-like member 20 has an outer edge portion 22 which is the end portion on its outer periphery side, a hole edge portion 23 of the through-hole 21, and an intermediate portion 24 disposed between the outer edge portion 22 and the hole edge portion 23.

[0039] As shown in Fig. 5, the peaks 11 of the accordion-shaped member 10 are formed by stacking two sheet-like members 20 in the thickness direction of the sheet-like members 20 and joining the outer edge portions 22 of the sheet-like members 20 together. The valleys 12 of the accordion-shaped member 10 are formed by stacking two sheet-like members 20 in the thickness direction of the sheet-like members 20 and joining the hole edge portions 23 of the sheet-like members 20 together. The joining portions between the outer edge portions 22 (i.e., the peaks 11) and the joining portions between the hole edge portions 23 (i.e., the valleys 12) are arranged alternately in the thickness direction of the sheet-like members 20. Examples of methods for joining the sheet-like members 20 include welding and sewing.

[0040] The connecting portion 15 of the accordion-shaped member 10 is formed from the same sheet-shaped member 20 as described above. The fixing portion 14 of the accordion-shaped member 10 is formed from a cylindrical member obtained by, for example, molding a material having the same flexibility as the sheet-shaped member 20 into a rectangular shape and joining two short sides together. A connection portion between the connecting portion 15 and the fixing portion 14 is formed by joining the hole edge portion 23 of the sheet-shaped member 20 to the end of the cylindrical member. In another embodiment, for example, the connecting portion 15 and the fixing portion 14 may be formed integrally.

[0041] Here, the radial dimension from the central axis CA to the peaks 11 is defined as the outer diameter, and the radial dimension from the central axis CA to the valleys 12 is defined as the inner diameter. The outer and inner diameters do not include the dimensions of the joints between the sheet-like members 20. The outer and inner diameters are preferably determined when the bellows-shaped member 10 is not elastically deformed, i.e., in its natural state. As shown in FIG. 1 , the bellows-shaped member 10 has a constant outer diameter OD1. The first portion 10A has a constant inner diameter ID1, and the second portion 10B has a constant inner diameter ID2. The inner diameter ID1 of the first portion 10A is larger than the inner diameter ID2 of the second portion 10B. Therefore, if the difference between the outer diameter and the inner diameter is defined as the inner-outer diameter difference, the inner-outer diameter difference DD1 of the first portion 10A is smaller than the inner-outer diameter difference DD2 of the second portion 10B.

[0042] The first portion 10A is configured to include at least one sheet-like member 20. In this embodiment, the first portion 10A is formed from two sheet-like members 20. The second portion 10B is configured to include at least one sheet-like member 20. In this embodiment, the second portion 10B is formed from 28 sheet-like members 20.

[0043] 3, the first sheet-like member 20A, which is the sheet-like member 20 constituting the first portion 10A, and the second sheet-like member 20B, which is the sheet-like member 20 constituting the second portion 10B, may be formed to have different sizes. For example, the area of ​​the through hole 21 in the first sheet-like member 20A may be larger than the area of ​​the through hole 21 in the second sheet-like member 20B. Furthermore, the first sheet-like member 20A and the second sheet-like member 20B may be the same sheet-like member 20, and the position or size of the portion connecting the sheet-like members 20 may be different.

[0044] As described above, the inner / outer diameter difference DD1 of the first portion 10A is smaller than the inner / outer diameter difference DD2 of the second portion 10B. More specifically, the outer diameter OD1 of the first portion 10A and the outer diameter OD2 of the second portion 10B are the same, and the inner diameter ID1 of the first portion 10A is larger than the inner diameter ID2 of the second portion 10B. This makes the first portion 10A less likely to expand or contract than the second portion 10B. In other words, the first portion 10A has higher rigidity than the second portion 10B.

[0045] In the accordion-shaped member 10, the first portion 10A, which has higher rigidity than the second portion 10B, is disposed near the fixing portion 14 where stress tends to concentrate. Therefore, early breakage of the accordion-shaped member 10 can be suppressed.

[0046] Furthermore, with the above configuration, for example, by increasing the difference between the inner and outer diameters in areas where durability is not required and decreasing the difference between the inner and outer diameters in areas where durability is required, it is possible to reduce the number of sheet-like members 20 required to form the bellows-like member 10 and reduce the number of steps required to join the sheet-like members 20 together, which makes it easier to reduce the manufacturing cost of the bellows-like member 10.

[0047] [Effects and Functions of First Embodiment] As described above, the accordion-shaped member 10 of the first embodiment has a plurality of peaks 11 that protrude radially outward and a plurality of valleys 12 that recess radially inward, arranged side by side in the axial direction, and the peaks 11 and the valleys 12 are each formed by joining two sheet-like members 20. The accordion-shaped member 10 has a first portion 10A and a second portion 10B that are connected in the axial direction, and the first portion 10A and the second portion 10B are each formed from at least one sheet-like member 20, and the first portion 10A has less elasticity than the second portion 10B.

[0048] With this configuration, it is possible to provide the accordion-shaped member 10 having the first portion 10A and the second portion 10B with different elasticity. For example, by considering the manner in which the accordion-shaped member 10 is used, and making the portion that is likely to be subjected to stress the first portion 10A, it is possible to more easily prevent the accordion-shaped member 10 from being damaged.

[0049] In embodiment 1, if the dimension from the center (center axis CA) in the radial direction to the peak portion 11 is defined as the outer diameter, the dimension from the center (center axis CA) in the radial direction to the valley portion 12 is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the inner / outer diameter difference, the inner / outer diameter difference DD1 of the first portion 10A is smaller than the inner / outer diameter difference DD2 of the second portion 10B.

[0050] With this configuration, the difference between the inner and outer diameters allows the stretchability of the first portion 10A to be smaller than that of the second portion 10B.

[0051] In the first embodiment, the first portion 10A is disposed near the end of the accordion-shaped member 10.

[0052] This configuration can increase the rigidity of the bellows-shaped member 10 near its end where stress tends to concentrate.

[0053] The manufacturing method of the accordion-shaped member 10 of embodiment 1 includes a sheet forming process of forming a plurality of flexible sheet-shaped members 20 each having through holes 21, and a sheet joining process of joining outer edge portions 22 of the sheet-shaped members 20 to form peak portions 11 and joining hole edge portions 23 of the through holes 21 to form valley portions 12. In the sheet joining process, a first portion 10A including at least one sheet-shaped member 20 and a second portion 10B axially connected to the first portion 10A and including at least one sheet-shaped member 20 are formed, and the first portion 10A is formed so as to have less elasticity in the axial direction compared to the second portion 10B.

[0054] According to this manufacturing method of the accordion-shaped member 10, by joining the sheet-shaped members 20, it is possible to provide the accordion-shaped member 10 having the first portion 10A and the second portion 10B with different elasticity.

[0055] In the manufacturing method of the accordion-shaped member 10 of embodiment 1, in the sheet joining process, if the dimension from the center to the peak 11 in the radial direction perpendicular to the axial direction is defined as the outer diameter, the dimension from the center to the valley 12 in the radial direction is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the inner / outer diameter difference, the first portion 10A is formed so that the inner / outer diameter difference DD1 is smaller than the inner / outer diameter difference DD2 of the second portion 10B.

[0056] According to such a manufacturing method of the accordion-shaped member 10, the difference between the inner and outer diameters makes it possible to make the stretchability of the first portion 10A smaller than that of the second portion 10B.

[0057] Second Embodiment A second embodiment of the present disclosure will be described with reference to Fig. 6. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0058] The accordion-shaped member 110 of the second embodiment has a main body 113, a fixing portion 14, and a connecting portion 15. The main body 113 of the accordion-shaped member 110 has two first portions 110A and one second portion 110B. The second portion 110B is formed by 24 sheet-shaped members 20.

[0059] The first portion 110A includes a third portion 110C and a fourth portion 110D that are connected in the axial direction. The third portion 110C and the fourth portion 110D each include two sheet-like members 20. The third portion 110C is connected to an end of the second portion 110B. The fourth portion 110D is connected to the connecting portion 15.

[0060] The inner / outer diameter difference DD3 of the third portion 110C is larger than the inner / outer diameter difference DD4 of the fourth portion 110D. More specifically, the outer diameter OD3 of the third portion 110C is equal to the outer diameter OD3 of the fourth portion 110D, and the inner diameter ID3 of the third portion 110C is smaller than the inner diameter ID4 of the fourth portion 110D. In other words, the valley 12 of the third portion 110C is deeper than that of the fourth portion 110D.

[0061] The inner-outer diameter difference DD5 of the second portion 110B is larger than the inner-outer diameter difference DD3 of the third portion 110C. More specifically, the outer diameter OD3 of the second portion 110B is equal to the outer diameter OD3 of the third portion 110C and the outer diameter OD3 of the fourth portion 110D. The inner diameter ID5 of the second portion 110B is smaller than the inner diameter ID3 of the third portion 110C.

[0062] The first portion 110A has two or more axially connected portions (third portion 110C and fourth portion 110D) with different inner and outer diameter differences. These two or more portions are arranged so that the difference in inner and outer diameters gradually increases toward the second portion 110B. This configuration reduces the difference in elasticity near the joint between the first portion 110A and the second portion 110B. This reduces stress concentration near the joint between the first portion 110A and the second portion 110B.

[0063] Third Embodiment A third embodiment of the present disclosure will be described with reference to Fig. 7. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0064] The accordion-shaped member 210 of the third embodiment has a main body 213, a fixing portion 14, and a connecting portion 15. The main body 213 of the accordion-shaped member 210 has two first portions 210A and one second portion 210B. The first portion 210A is formed of one sheet-shaped member 20. The second portion 210B is formed of 30 sheet-shaped members 20.

[0065] The inner / outer diameter difference DD6 of the first portion 210A is smaller than the inner / outer diameter difference DD7 of the second portion 210B. More specifically, the inner diameter ID6 of the first portion 210A is equal to the inner diameter ID6 of the second portion 210B. The outer diameter OD6 of the first portion 210A is smaller than the outer diameter OD7 of the second portion 210B. Therefore, the first portion 210A has higher rigidity than the second portion 210B.

[0066] [Fourth Embodiment] A fourth embodiment of the present disclosure will be described with reference to Figures 8 and 9. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0067] 8 is a side view of a conventional bellows-shaped member 1010 not included in the present disclosure, under tension and compression. The bellows-shaped member 1010 is formed by joining a plurality of sheet-shaped members 20, and has a plurality of peaks 11 and a plurality of valleys 12. The bellows-shaped member 1010 includes a main body portion 1013, a fixing portion 14, and a connecting portion 15. The main body portion 1013 of the bellows-shaped member 1010 has a constant inner diameter IDX, a constant outer diameter ODX, and a constant inner-outer diameter difference DDX.

[0068] Here, consider a case where the accordion-shaped member 1010 is arranged so that its axial direction is approximately aligned with the vertical direction (up-down direction). When the accordion-shaped member 1010 is pulled, as shown in the left part of Fig. 8, each of the sheet-shaped members 20 constituting the accordion-shaped member 1010 is stretched in approximately the same manner. On the other hand, when the accordion-shaped member 1010 is compressed, as shown in the right part of Fig. 8, each of the sheet-shaped members 20 constituting the upper part of the accordion-shaped member 1010 is slightly stretched by gravity, and each of the sheet-shaped members 20 constituting the lower part of the accordion-shaped member 1010 is contracted. In other words, as the upper part of the accordion-shaped member 1010 stretches due to its own weight, the lower part of the accordion-shaped member 1010 is wrinkled and becomes slack. When the lower part of the accordion-shaped member 1010 is in this loose state, adjacent sheet-shaped members 20 are likely to come into contact with each other, and friction between the sheet-shaped members 20 may cause the accordion-shaped member 1010 to break prematurely or generate noise when compressed.

[0069] As shown in Fig. 9, the accordion-shaped member 310 of the fourth embodiment has a main body 313, a fixing portion 14, and a connecting portion 15. The main body 313 of the accordion-shaped member 310 has one first portion 310A and one second portion 310B. The first portion 310A is formed from 15 first sheet-shaped members 20A. The second portion 310B is formed from 16 second sheet-shaped members 20B. The first portion 310A and the second portion 310B each include a plurality of peaks 11 and a plurality of valleys 12.

[0070] The inner / outer diameter difference DD8 of the first portion 310A is smaller than the inner / outer diameter difference DD9 of the second portion 310B. More specifically, the outer diameter OD8 of the first portion 310A and the outer diameter OD8 of the second portion 310B are the same, and the inner diameter ID8 of the first portion 310A is larger than the inner diameter ID9 of the second portion 310B. This makes the first portion 310A more rigid than the second portion 310B.

[0071] Here, consider a case where the accordion-shaped member 310 is arranged so that its axial direction is substantially aligned with the vertical direction (up-down direction) and the first portion 310A is disposed above the second portion 310B. Because the relatively rigid first portion 310A is disposed at the upper portion of the accordion-shaped member 310, when the accordion-shaped member 310 is compressed, the upper portion of the accordion-shaped member 310 is less likely to stretch due to its own weight, as shown in the right portion of Figure 9. As a result, slack is less likely to occur at the lower portion of the accordion-shaped member 310, which can prevent early damage to the accordion-shaped member 310 due to contact between adjacent sheet-shaped members 20 and noise generation during compression.

[0072] [Effects and Functions of Embodiment 4] In the accordion-shaped member 310 of embodiment 4, the axial direction and the vertical direction are arranged so as to approximately coincide with each other, and the first part 310A includes a plurality of peaks 11 and a plurality of valleys 12 and forms the upper part of the accordion-shaped member 310.

[0073] With this configuration, by increasing the rigidity of the upper part of the bellows-shaped member 310, which is more likely to be subjected to its own weight, the lower part of the bellows-shaped member 310 is less likely to slacken.

[0074] Fifth Embodiment A fifth embodiment of the present disclosure will be described with reference to Fig. 10. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0075] 10 is a cross-sectional view showing a part of a robot 1 including a bellows-shaped member 410 of embodiment 5. The robot 1 includes a first shaft 2, a second shaft 3 connected to the lower end of the first shaft 2, a first cylindrical portion 4 disposed radially outward of the first shaft 2, a second cylindrical portion 5 disposed radially outward of the second shaft 3, and the bellows-shaped member 410 covering parts of the first shaft 2 and the second shaft 3.

[0076] The first cylindrical portion 4 is disposed outside the first shaft 2 without contacting the first shaft 2. The first cylindrical portion 4 is disposed above the second cylindrical portion 5. The second shaft 3 includes a shaft connecting portion 3A that is disposed radially outside the first shaft 2 and fixed to the first shaft 2. The shaft connecting portion 3A has a shape that protrudes radially outward compared to the first shaft 2. The second cylindrical portion 5 is disposed radially outside the lower part of the shaft connecting portion 3A via a bearing 5A.

[0077] The accordion-shaped member 410 includes a main body portion 413, a first fixing portion 414A, a second fixing portion 414B, a first connecting portion 415A, and a second connecting portion 415B. The first fixing portion 414A is disposed above the main body portion 413 and is connected to the upper end of the main body portion 413 by the first connecting portion 415A. The first fixing portion 414A is fixed to the first cylindrical portion 4. The second fixing portion 414B is disposed below the main body portion 413 and is connected to the lower end of the main body portion 413 by the second connecting portion 415B. The second fixing portion 414B is fixed to the second cylindrical portion 5.

[0078] The main body 413 includes a first portion 410A and a second portion 410B. The first portion 410A is coupled to the lower end of the second portion 410B. The upper end of the second portion 410B is connected to the first fixed portion 414A via a first connecting portion 415A. The lower end of the first portion 410A is connected to the second fixed portion 414B via a second connecting portion 415B.

[0079] The first portion 410A is configured to include eight sheet-like members 20. The second portion 410B is configured to include 27 sheet-like members 20. The first portion 410A and the second portion 410B each have a plurality of peaks 11 and a plurality of valleys 12.

[0080] The outer diameter OD10 of the first portion 410A is equal to the outer diameter OD10 of the second portion 410B. The inner diameter ID10 of the first portion 410A is larger than the inner diameter ID11 of the second portion 410B. Therefore, the inner-outer diameter difference DD10 of the first portion 410A is smaller than the inner-outer diameter difference DD11 of the second portion 410B. This makes the first portion 410A less stretchable than the second portion 410B.

[0081] In this embodiment, the first portion 410A having a large inner diameter ID10 is disposed on the outside of the shaft coupling portion 3A, which has a particularly large radial dimension among the portions of the robot 1 covered by the bellows-shaped member 410. This makes it possible to ensure surplus space between the shaft coupling portion 3A and the bellows-shaped member 410. Therefore, even if the robot 1 moves horizontally or the like during extension or vertical movement of the bellows-shaped member 410 and the bellows-shaped member 410 is shaken horizontally, interference between the bellows-shaped member 410 and the shaft coupling portion 3A can be avoided.

[0082] Additionally, a second portion 410B having an inner diameter ID11 smaller than the inner diameter ID10 is disposed on the outside of the first shaft 2. In the second portion 410B having an inner diameter ID11 smaller than that of the first portion 410A, the inner-outer diameter difference DD11 is increased, thereby enabling greater stretchability per sheet-like member 20. Therefore, compared to a configuration in which the bellows-shaped member has a constant inner diameter ID10, the number of sheet-like members 20 constituting the bellows-shaped member 410 can be reduced. This allows for reduced manufacturing costs for the bellows-shaped member 410.

[0083] [Effects of embodiment 5] In the accordion-shaped member 410 according to embodiment 5, the first portion 410A includes a plurality of peaks 11 and a plurality of valleys 12, and the inner diameter ID10 of the first portion 410A is larger than the inner diameter ID11 of the second portion 410B.

[0084] With this configuration, for example, when the accordion-shaped member 410 is used to cover the accommodated portion (part of the robot 1), the part of the accommodated portion with the larger radial dimension (shaft connecting portion 3A) can be accommodated inside the first part 410A of the accordion-shaped member 410, thereby suppressing interference between the accordion-shaped member 410 and the accommodated portion.

[0085] Sixth Embodiment A sixth embodiment of the present disclosure will be described with reference to Fig. 11. Hereinafter, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and detailed description thereof may be omitted.

[0086] The accordion-shaped member 510 of the sixth embodiment includes a first portion 510A and a second portion 510B. The sheet-shaped member 20 constituting the first portion 510A is a first sheet-shaped member 520A. The sheet-shaped member 20 constituting the second portion 510B is a second sheet-shaped member 20B. The first sheet-shaped member 520A of the present embodiment is formed by stacking two second sheet-shaped members 20B. Therefore, the peak portions 11 and the valley portions 12 of the accordion-shaped member 510 of the sixth embodiment are each formed by joining at least two (more specifically, two, three, or four) second sheet-shaped members 20B.

[0087] The first sheet-like member 520A is thicker than the second sheet-like member 20B and is therefore less susceptible to elastic deformation than the second sheet-like member 20B. Therefore, the first portion 510A has higher rigidity than the second portion 510B. Furthermore, since the first sheet-like member 520A is formed by stacking two second sheet-like members 20B, it is only necessary to form one type of sheet-like member 20 (i.e., the second sheet-like member 20B) in the process of forming the sheet-like member 20. Note that the joining (i.e., welding or sewing) of three or more second sheet-like members 20B may be performed in a single joining process, or in two or more joining processes.

[0088] [Effects and effects of embodiment 6] In the accordion-shaped member 510 of embodiment 6, the sheet-shaped member 20 constituting the first portion 510A is a first sheet-shaped member 520A, and the sheet-shaped member 20 constituting the second portion 510B is a second sheet-shaped member 20B, and the first sheet-shaped member 520A is formed by stacking two second sheet-shaped members 20B.

[0089] With this configuration, the difference in thickness of the sheet-like member 20 constituting each part (first part 510A, second part 510B) allows the stretchability of the first part 510A to be less than that of the second part 510B.

[0090] In the manufacturing method of the accordion-shaped member 510 according to the sixth embodiment, the sheet-shaped member 20 constituting the first portion 510A is a first sheet-shaped member 520A, the sheet-shaped member 20 constituting the second portion 510B is a second sheet-shaped member 20B, and the first sheet-shaped member 520A is formed by stacking two second sheet-shaped members 20B.

[0091] According to this manufacturing method of the accordion-shaped member 510, the elasticity of the first part 510A can be made smaller than that of the second part 510B by varying the thickness of the sheet-shaped member 20 constituting each part (first part 510A, second part 510B).

[0092] [Other Embodiments] (1) The present disclosure also includes a bellows-shaped member 610 shown in FIG. 12 , for example. The bellows-shaped member 610 includes a first portion 610A and a second portion 610B. The sheet-shaped member 20 constituting the first portion 610A is a first sheet-shaped member 620A. The sheet-shaped member 20 constituting the second portion 610B is a second sheet-shaped member 20B. The first sheet-shaped member 620A is made of a material that is less susceptible to elastic deformation than the second sheet-shaped member 20B. For example, the hardness of the first sheet-shaped member 620A is higher than the hardness of the second sheet-shaped member 20B. The shape of the first sheet-shaped member 620A may be the same as that of the second sheet-shaped member 20B.

[0093] (2) The bellows-shaped member of the present disclosure may not include a fixing portion and a connecting portion. Furthermore, the bellows-shaped member of the present disclosure may include a fixing portion having a configuration different from the fixing portions 14, 414A, and 414B described above. For example, the present disclosure also includes a bellows-shaped member 710 shown in FIG. 13 . The bellows-shaped member 710 includes a first portion 10A and a second portion 10B similar to those in the first embodiment, a first connecting portion 715A, a second connecting portion 715B, and a fixing portion 714. The first connecting portion 715A is formed similarly to the connecting portion 15 in the first embodiment. The second connecting portion 715B is a cylindrical member similar to the fixing portion 14 in the first embodiment. The fixing portion 714 is connected to the end of the second connecting portion 715B opposite to the first connecting portion 715A. The fixing portion 714 may be a plate-shaped member thicker than the sheet-shaped member 20. The fixing portion 714 has an annular shape when viewed in the axial direction. That is, a through hole 714A is provided in the center of the fixing portion 714. A plurality of fixing holes 714B may be provided in the outer edge of the fixing portion 714. For example, the fixing portion 714 may be fixed to a robot, a machine tool, or the like by inserting bolts into the fixing holes 714B and fastening the bolts. Furthermore, the fixing portion 714 may be fixed to a robot, a machine tool, or the like by clamping the fixing portion 714 in the axial direction with fixing members made of metal or the like.

[0094] (3) The shape of the bellows-shaped member and the openings of the present disclosure, as viewed in the axial direction, does not have to be circular and may be, for example, polygonal. For example, the present disclosure also includes a bellows-shaped member 810 shown in FIGS. 14 to 16 . As shown in FIG. 14 , the shape of the bellows-shaped member 810 and the openings 816 as viewed in the axial direction is rectangular. The sheet-shaped member 820 (and the through-holes 821 of the sheet-shaped member 820 (see FIG. 16 )) that constitute the bellows-shaped member 810 are rectangular. As shown in FIG. 16 , the sheet-shaped member 820 that constitutes the first portion 810A is the first sheet-shaped member 820A. The sheet-shaped member 820 that constitutes the second portion 810B is the second sheet-shaped member 820B. As shown in FIG. 15 , the bellows-shaped member 810 includes a first portion 810A, a second portion 810B, and a fixing portion 814. The inner diameter ID12 of the first portion 810A is larger than the inner diameter ID13 of the second portion 810B. The first portion 810A and the second portion 810B have the same outer diameter OD12. Therefore, the inner / outer diameter difference DD12 of the first portion 810A is smaller than the inner / outer diameter difference DD13 of the second portion 810B. Note that, when the inner diameter, outer diameter, and inner / outer diameter difference each exhibit different values ​​depending on the measurement direction, as in this embodiment, the magnitude relationship between the inner diameter, outer diameter, and inner / outer diameter difference of the first portion and the second portion is defined by the values ​​measured from the same radial direction toward the central axis. The fixing portion 814 is configured substantially similarly to the fixing portion 714, except that it has a rectangular shape when viewed axially. As shown in FIG. 14 , the fixing portion 814 has a through hole 814A and multiple fixing holes 814B. As shown in FIG. 16, an end of the first portion 810A, which is opposite to the portion joined to the second portion 810B, is joined to the edge of the through-hole 814A of the fixing portion 814.

[0095] (4) The configuration of the robot 1 of embodiment 5 is merely an example, and the accordion-shaped member of the present disclosure is intended to be applied to robots, machine tools, and the like of any configuration.

[0096] (5) In the sixth embodiment, the first sheet-like member 620A is formed by stacking two second sheet-like members 20B, but the first sheet-like member may be formed by stacking three or more second sheet-like members. Furthermore, the first sheet-like member may not be formed by stacking second sheet-like members, but may be a single sheet-like member that is formed thicker than the second sheet-like member.

[0097] 1: Robot 2: First shaft 3: Second shaft 3A: Shaft connecting portion 4: First cylindrical portion 5: Second cylindrical portion 5A: Bearing 10: Bellows-shaped member 10A: First portion 10B: Second portion 11: Peak portion 12: Valley portion 13: Main body portion 14: Fixing portion 15: Connecting portion 16: Opening 20: Sheet-shaped member 20A: First sheet-shaped member 20B: Second sheet-shaped member 21: Through hole 22: Outer edge portion 23: Hole edge portion 24: Intermediate portion CA: Central axis DD1: Inner / outer diameter difference of first portion 10A DD2: Inner / outer diameter difference of second portion 10B ID1: Inner diameter of first portion 10A ID2: Inner diameter of second portion 10B OD1: Outer diameters of first portion 10A and second portion 10B 110: Bellows-shaped member 110A: First portion 110B: Second portion 110C: Third portion 110D: Fourth portion 113: Main body portion DD3: Difference between inner and outer diameters of the third portion 110C DD4: Difference between inner and outer diameters of the fourth portion 110D DD5: Difference between inner and outer diameters of the second portion 110B ID3: Inner diameter of the third portion 110C ID4: Inner diameter of the fourth portion 110D ID5: Inner diameter of the second portion 110B OD3: Outer diameters of the first portion 110A and the second portion 110B 210: Bellows-shaped member 210A: First portion 210B: Second portion 213: Main body portion DD6: Difference between inner and outer diameters of the first portion 210A DD7: Difference between inner and outer diameters of the second portion 210B ID6: Inner diameter of first portion 210A and second portion 210B OD6: Outer diameter of first portion 210A OD7: Outer diameter of second portion 210B 310: Bellows-shaped member 310A: First portion 310B: Second portion 313: Main body portion DD8: Difference between inner and outer diameters of first portion 310A DD9: Difference between inner and outer diameters of second portion 310B ID8: Inner diameter of first portion 310A ID9: Inner diameter of second portion 310B OD8: Outer diameter of first portion 310A and second portion 310B 410: Bellows-shaped member 410A: First portion 410B: Second portion 413: Main body portion 414A: First fixing portion 414B: Second fixing portion 415A: First connecting portion 415B: Second connecting portion DD10: difference between inner and outer diameters of the first portion 410A DD11: difference between inner and outer diameters of the second portion 410B ID10: inner diameter of the first portion 410A ID11: inner diameter of the second portion 410B OD10: outer diameters of the first portion 410A and the second portion 410B 510: bellows-shaped member 510A: first portion 510B: second portion 520A: first sheet-shaped member610: Bellows-shaped member 610A: First portion 610B: Second portion 620A: First sheet-shaped member 710: Bellows-shaped member 714: Fixing portion 714A: Through hole 714B: Fixing hole 715A: First connecting portion 715B: Second connecting portion 810: Bellows-shaped member 810A: First portion 810B: Second portion 814: Fixing portion 814A: Through hole 814B: Fixing hole 816: Opening 820: Sheet-shaped member 820A: First sheet-shaped member 820B: Second sheet-shaped member 821: Through hole DD12: Difference between inner and outer diameters of first portion 810A DD13: Difference between inner and outer diameters of second portion 810B ID12: Inner diameter of first portion 810A ID13: inner diameter of the second portion 810B OD12: outer diameter of the first portion 810A and the second portion 810B

Claims

1. A corrugated member in which a plurality of ridges protruding radially outward and valleys recessed radially inward are arranged side by side in the axial direction, and the ridges and valleys are each formed by joining at least two sheet-like members, the corrugated member having a first portion and a second portion continuous in the axial direction, the first portion and the second portion each being formed from at least one of the sheet-like members, and the first portion having less elasticity than the second portion.

2. The corrugated member according to claim 1, wherein when the dimension from the center in the radial direction to the ridge is defined as the outer diameter, the dimension from the center in the radial direction to the valley is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the outer-inner diameter difference, the outer-inner diameter difference of the first portion is smaller than the outer-inner diameter difference of the second portion.

3. The sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the first sheet-like member is formed by stacking two or more of the second sheet-like members.

4. The sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the thickness of the first sheet-like member is larger than the thickness of the second sheet-like member.

5. The sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the hardness of the first sheet-like member is higher than the hardness of the second sheet-like member.

6. The corrugated member according to any one of claims 1 to 5, wherein the first portion is arranged near an end of the corrugated member.

7. The corrugated member according to any one of claims 1 to 5, wherein the axial direction and the vertical direction are arranged to be substantially coincident, and the first portion includes a plurality of the ridges and a plurality of the valleys and constitutes an upper portion of the corrugated member.

8. The corrugated member according to claim 2, wherein the first portion includes a plurality of the ridges and a plurality of the valleys, and the inner diameter of the first portion is larger than the inner diameter of the second portion.

9. A method for manufacturing a corrugated member, comprising: a sheet forming step of forming a plurality of flexible sheet-like members having through holes; and a sheet joining step of joining outer edge portions of the sheet-like members to form ridges and joining hole edge portions of the through holes to form valleys, wherein in the sheet joining step, a first portion including at least one of the sheet-like members and a second portion axially continuous with the first portion and including at least one of the sheet-like members are formed, and the first portion is formed to have less stretchability in the axial direction than the second portion.

10. The method for manufacturing a corrugated member according to claim 9, wherein in the sheet joining step, when the dimension from the center in the radial direction orthogonal to the axial direction to the ridge is defined as the outer diameter, the dimension from the center in the radial direction to the valley is defined as the inner diameter, and the difference between the outer diameter and the inner diameter is defined as the outer-inner diameter difference, the outer-inner diameter difference of the first portion is formed to be smaller than the outer-inner diameter difference of the second portion.

11. The method for manufacturing a corrugated member according to claim 9, wherein the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the first sheet-like member is formed by stacking two or more of the second sheet-like members.

12. The method for manufacturing a corrugated member according to claim 9, wherein the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the thickness of the first sheet-like member is larger than the thickness of the second sheet-like member.

13. The method for manufacturing a corrugated member according to claim 9, wherein the sheet-like member constituting the first portion is a first sheet-like member, the sheet-like member constituting the second portion is a second sheet-like member, and the hardness of the first sheet-like member is higher than the hardness of the second sheet-like member.

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