Spring

Abstract

This spring has an annular peripheral wall (11). The peripheral wall (11) has a plurality of slit groups (12) formed at intervals in the axial direction of the peripheral wall (11). Each of the slit groups (12) has a plurality of first slits (13) extending in the circumferential direction of the peripheral wall (11) and formed at intervals in the circumferential direction. A plurality of second slits (14) formed at intervals in the circumferential direction allow communication between the first slits (13) of two slit groups (12) adjacent to each other in the axial direction. The peripheral wall (11) has two opposing surfaces (15) that face each other across each of the second slits (14) in the circumferential direction. Each of the opposing surfaces (15) intersects the axial direction.

Description

spring

[0001] The present disclosure relates to springs.

[0002] As shown in Fig. 20, Patent Document 1 discloses a cylindrical spring having an annular peripheral wall 111. The peripheral wall 111 has a plurality of slit groups 112 formed at intervals in the axial direction of the peripheral wall 111. Each slit group 112 has two first slits 113 extending in the circumferential direction of the peripheral wall 111 and formed at intervals in the circumferential direction. The peripheral wall 111 has a plurality of second slits 114 that connect the first slits 113 of two slit groups 112 that are adjacent to each other in the axial direction.

[0003] The peripheral wall 111 has two opposing surfaces 115 that face each other in the circumferential direction across the second slit 114. The opposing surfaces 115 are parallel to each other and extend in the axial direction.

[0004] The spring 110 expands and contracts as the width of the first slit 113 in the axial direction expands and contracts.

[0005] Design Registration No. 1226279

[0006] In factories and other places, when attaching springs to equipment or moving equipment with springs attached, the springs may expand and contract, which can reduce workability. Furthermore, when transporting springs, such as during shipping, excessive external forces may act on the springs, causing plastic deformation and changing the spring's characteristics. Therefore, it is desirable to suppress axial deformation of springs when they are not in use.

[0007] The following describes various aspects of the spring for solving the above problems: [Aspect 1] A spring having an annular peripheral wall, the peripheral wall having a plurality of slit groups formed at intervals in an axial direction of the peripheral wall, each of the slit groups having a plurality of first slits extending in the circumferential direction of the peripheral wall and formed at intervals in the circumferential direction, a plurality of second slits communicating with the first slits of two of the slit groups adjacent to each other in the axial direction and formed at intervals in the circumferential direction, and two opposing surfaces opposing each other in the circumferential direction with each of the second slits sandwiched therebetween, and each of the opposing surfaces intersecting the axial direction.

[0008] The spring expands and contracts as the width of the first slit in the axial direction expands and contracts, and at this time, the two opposing surfaces that face each other across the second slit move in opposite directions in the axial direction.

[0009] According to the above configuration, the two opposing surfaces intersect with each other in the axial direction. Therefore, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, the two opposing surfaces are caught on the rod-shaped member in at least one direction in the axial direction. This restricts the two opposing surfaces from moving toward the rod-shaped member in the axial direction. Therefore, by inserting the rod-shaped member into the second slit, at least one of the expansion and contraction of the spring can be suppressed when the spring is not in use.

[0010] [Aspect 2] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a concave surface, and the second slit includes a first region in which the distance between the two opposing concave surfaces is a first distance, and a second region located on both sides of the first region in the axial direction, in which the distance between the two concave surfaces is a second distance smaller than the first distance.

[0011] According to the above configuration, the second region is located between the two concave surfaces on both sides of the first region in the axial direction. The second distance between the two concave surfaces in the second region is smaller than the first distance between the two concave surfaces in the first region. Therefore, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, each of the two concave surfaces is caught on the rod-shaped member on both sides in the axial direction. This restricts movement of the two opposing surfaces in both directions in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, expansion and contraction of the spring when the spring is not in use can be suppressed.

[0012] [Aspect 3] A spring described in [Aspect 2], wherein the two concave surfaces are curved in an arc along the same imaginary circle centered on a central axis perpendicular to the axial direction and passing through the second slit.

[0013] According to the above configuration, when a cylindrical rod-shaped member having the same diameter as the imaginary circle is inserted into the second slit to suppress expansion and contraction of the spring, there is no need to adjust the rotational phase of the rod-shaped member. This allows the rod-shaped member to be easily inserted into the second slit. This makes it easy to suppress expansion and contraction of the spring when the spring is not in use.

[0014] [Aspect 4] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc shape along the same imaginary circle that is perpendicular to the axial direction and has its center at a central axis that passes through the first slit.

[0015] According to the above configuration, by inserting a rod-shaped member into the second slit, each of the two concave surfaces is caught on one side of the rod-shaped member in the axial direction. This prevents the two opposing surfaces, which move in opposite directions in the axial direction when the spring expands or contracts, from moving toward the rod-shaped member in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, it is possible to suppress expansion and contraction of the spring when it is not in use.

[0016] Furthermore, with the above configuration, when a cylindrical rod-shaped member having the same diameter as the imaginary circle is inserted into the second slit to suppress expansion and contraction of the spring, there is no need to adjust the rotational phase of the rod-shaped member. This allows the rod-shaped member to be easily inserted into the second slit. This makes it easy to suppress expansion and contraction of the spring when the spring is not in use.

[0017] [Aspect 5] A spring described in [Aspect 2], in which the two concave surfaces are curved in an arc along each of two imaginary circles of the same diameter centered on a central axis perpendicular to the axial direction and passing through the second slit.

[0018] According to the above configuration, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, each of the two concave surfaces is caught on the rod-shaped member on both sides in the axial direction, thereby restricting the two opposing surfaces from moving in both directions in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, it is possible to suppress expansion and contraction of the spring when the spring is not in use.

[0019] [Aspect 6] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc shape along each of two imaginary circles of the same diameter that are perpendicular to the axial direction and centered on a central axis that passes through the first slit.

[0020] According to the above configuration, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, each of the two concave surfaces is caught on one side of the rod-shaped member in the axial direction. This restricts the two opposing surfaces, which move in opposite directions in the axial direction when the spring expands or contracts, from moving toward the rod-shaped member in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, it is possible to suppress the expansion or contraction of the spring when it is not in use.

[0021] [Aspect 7] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc along a first imaginary circle centered on a central axis that is perpendicular to the axial direction and passes through the first slit, and a second imaginary circle of the same diameter as the first imaginary circle and centered on a central axis that is perpendicular to the axial direction and passes through the second slit.

[0022] According to the above configuration, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, the concave surface along the first imaginary circle catches on the rod-shaped member on one side in the axial direction. Furthermore, the concave surface along the second imaginary circle catches on the rod-shaped member on both sides in the axial direction. This restricts the concave surface along the first imaginary circle from moving toward the rod-shaped member in the axial direction. Furthermore, the concave surface along the second imaginary circle is restricted from moving on both sides in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, it is possible to suppress expansion and contraction of the spring when the spring is not in use.

[0023] [Aspect 8] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc along each of two imaginary circles of the same diameter centered on a central axis that is perpendicular to the axial direction and passes through each of the two first slits that communicate with the second slits.

[0024] According to the above configuration, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, the two concave surfaces catch on the rod-shaped member from opposite sides in the axial direction. This restricts the two opposing surfaces, which move in opposite directions in the axial direction when the spring compresses, from moving toward the rod-shaped member in the axial direction. Therefore, by inserting the rod-shaped member into the second slit, it is possible to suppress the compression of the spring when it is not in use.

[0025] [Aspect 9] A spring as described in [Aspect 1], wherein each of the opposing surfaces includes a convex surface, and the second slit includes a first region in which the distance between the two opposing convex surfaces is a first distance, and a second region located on both sides of the first region in the axial direction, in which the distance between the two convex surfaces is a second distance greater than the first distance.

[0026] According to the above configuration, the second region is located between the two convex surfaces on both sides of the first region in the axial direction. The second distance between the two convex surfaces in the second region is greater than the first distance between the two convex surfaces in the first region. Therefore, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, each of the two convex surfaces is caught on the rod-shaped member on both sides in the axial direction. This restricts movement of the two opposing surfaces on both sides in the axial direction. Therefore, by inserting a rod-shaped member into the second slit, expansion and contraction of the spring when not in use can be suppressed.

[0027] [Aspect 10] A spring as described in [Aspect 1], wherein one of the opposing surfaces includes a concave surface, the other of the opposing surfaces includes a convex surface opposite the concave surface, and the second slit includes a region where the distance between the opposing concave and convex surfaces is constant throughout the axial direction.

[0028] According to the above configuration, the distance between the concave and convex surfaces is constant throughout the axial direction. Therefore, by inserting a rod-shaped member having the same cross-sectional shape as the second slit and whose movement is restricted into the second slit, the concave and convex surfaces of the two opposing surfaces are caught on the rod-shaped member on both sides of the axial direction. This restricts the two opposing surfaces from moving in both directions of the axial direction. Therefore, by inserting a rod-shaped member into the second slit, it is possible to suppress expansion and contraction of the spring when the spring is not in use.

[0029] According to the present disclosure, deformation of the spring in the axial direction when the spring is not in use can be suppressed.

[0030] FIG. 1 is a perspective view showing a spring of one embodiment. FIG. 2 is a front view of the spring of FIG. 1. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2. FIG. 5 is an enlarged front view showing a second slit of the spring of FIG. 1. FIG. 6 is a front view showing the spring of FIG. 1 in an expanded state. FIG. 7 is a front view showing the spring of FIG. 1 in a compressed state. FIG. 8 is a front view showing a state in which a rod-shaped member is inserted into the second slit of the spring of FIG. 1. FIG. 9 is a front view showing a second slit of a first modified example. FIG. 10 is a front view showing a second slit of a second modified example. FIG. 11 is a front view showing a second slit of a third modified example. FIG. 12 is a front view showing a second slit of a fourth modified example. FIG. 13 is a front view showing a second slit of a fifth modified example. FIG. 14 is a front view showing a second slit of a sixth modified example. FIG. 15 is a front view showing a second slit of a seventh modified example. Fig. 16 is a front view showing the second slit of an eighth modified example. Fig. 17 is a front view showing the second slit of a ninth modified example. Fig. 18 is a front view showing the second slit of a tenth modified example. Fig. 19 is a front view showing the second slit of an eleventh modified example. Fig. 20 is a perspective view showing a conventional spring.

[0031] An embodiment of a spring will now be described with reference to Figures 1-8. As used in this description, the term "annular" can refer to any structure that forms a loop, or to continuous shapes with no ends, as well as generally loop-shaped structures with gaps, such as C-shapes. Note that "annular" shapes include, but are not limited to, circles, ellipses, and polygons with sharp or rounded corners.

[0032] 1, the spring 10 is cylindrical and has an annular peripheral wall 11. In this embodiment, the peripheral wall 11 is circular when viewed from the axial direction. The spring 10 is made of a metal material.

[0033] Hereinafter, the direction along the central axis C1 of the peripheral wall 11 will be referred to as the "axial direction." The circumferential direction of the peripheral wall 11 centered on the central axis C1 will be simply referred to as the "circumferential direction." The radial direction of the peripheral wall 11 centered on the central axis C1 will be simply referred to as the "radial direction."

[0034] 1 and 2, the peripheral wall 11 has a plurality of slit groups 12 formed at intervals in the axial direction. Each slit group 12 extends in the circumferential direction and has a plurality of first slits 13 formed at intervals in the circumferential direction. Each first slit 13 penetrates the peripheral wall 11 in the radial direction. The width of each first slit 13 in the axial direction is constant throughout the entire circumferential direction.

[0035] 3 and 4, each slit group 12 has, for example, two first slits 13. The multiple slit groups 12 are formed at intervals in the axial direction with a phase shift of 45° on one side in the circumferential direction. Therefore, the phases of two first slits 13 adjacent to each other in the axial direction are shifted by 45° in the circumferential direction.

[0036] 1 and 2 , the peripheral wall 11 has a plurality of second slits 14. Each second slit 14 penetrates the peripheral wall 11 in the radial direction. Each second slit 14 connects the first slits 13 of two axially adjacent slit groups 12. The two axially adjacent slit groups 12 communicate with each other via two second slits 14 located on opposite sides in the radial direction across the central axis C1.

[0037] Each second slit 14 communicates with the ends of two axially adjacent first slits 13. The two second slits 14 connected to both ends of each first slit 13 extend from the first slit 13 in opposite directions in the axial direction.

[0038] The peripheral wall 11 has a plurality of leaf spring portions 22 formed at intervals in the axial direction. A group of slits 12 is formed between two adjacent leaf spring portions 22 in the axial direction. Each leaf spring portion 22 has a plurality of arc portions 23 that extend in an arc shape in the circumferential direction and face each other in the circumferential direction with gaps between them.

[0039] 3 and 4, each leaf spring portion 22 has, for example, two arc portions 23. The leaf spring portions 22 are formed at intervals in the axial direction with a phase shift of 45° on one side in the circumferential direction. Therefore, the phases of two arc portions 23 adjacent to each other in the axial direction are shifted by 45° in the circumferential direction.

[0040] The peripheral wall 11 has a plurality of connecting portions 24. Each connecting portion 24 connects the arc portions 23 of two axially adjacent leaf spring portions 22. The two axially adjacent leaf spring portions 22 are connected via two connecting portions 24 located on opposite sides in the radial direction across the central axis C1.

[0041] Each connecting portion 24 connects the ends of two adjacent arc portions 23 in the axial direction. The two connecting portions 24 connected to both ends of each arc portion 23 extend in opposite directions in the axial direction from the arc portion 23. Both ends of each arc portion 23 extend in a cantilevered manner from the connecting portion 24 in the circumferential direction.

[0042] The two first slits 13 of the slit group 12 are formed by gaps between two adjacent leaf spring portions 22 in the axial direction and two connecting portions 24 connecting the two leaf spring portions 22. The two second slits 14 are formed by gaps between two adjacent arc portions 23 in the circumferential direction.

[0043] 5, each arcuate portion 23 has opposing surfaces 15 at both ends in the circumferential direction that face the ends of other arcuate portions 23. Each leaf spring portion 22 has a total of four opposing surfaces 15. Each opposing surface 15 forms a second slit 14.

[0044] Each of the two opposing surfaces 15 (hereinafter, sometimes simply referred to as the two opposing surfaces 15) that face each other across the second slit 14 includes a concave surface 16. In this embodiment, the entire opposing surface 15 is the concave surface 16. The two concave surfaces 16 of the two opposing surfaces 15 face each other in the circumferential direction. Each concave surface 16 extends over the entire radial direction of the arc portion 23. Therefore, each concave surface 16 is continuous with the outer peripheral surface and the inner peripheral surface of the arc portion 23.

[0045] The two concave surfaces 16 intersect with the axial direction. More specifically, the two concave surfaces 16 are curved in an arc shape along the same imaginary circle V, which is centered on a central axis C2 that is perpendicular to the axial direction and passes through the second slit 14. The two concave surfaces 16 are located on the circumference of the same imaginary circle V. The central axis C2 of the imaginary circle V is a straight line extending in the radial direction that passes through the center of the second slit 14 in the axial direction and intersects with the central axis C1 of the peripheral wall 11. The diameter of the imaginary circle V is larger than the width of the arc portion 23 in the axial direction and smaller than the sum of the width of the arc portion 23 in the axial direction and the width of the two first slits 13 adjacent to the arc portion 23.

[0046] Each second slit 14 has a first region A1 and two second regions A2 located on either side of the first region A1 in the axial direction. The first region A1 is a region where the distance between two opposing concave surfaces 16 is a first distance d1. The second region A2 is a region where the distance between the two concave surfaces 16 is a second distance d2 that is smaller than the first distance d1. The first distance d1 is the distance between the most recessed portions of the two concave surfaces 16. The second distance d2 is the distance between the portions of the two concave surfaces 16 excluding the most recessed portions. Any region of the second slit 14 other than the first region A1 can be the second region A2. The second distance d2 decreases as the distance from the first region A1 increases in the axial direction. For convenience, FIG. 5 illustrates the minimum second distance d2.

[0047] 6 and 7 , the spring 10 expands and contracts as each arc portion 23 elastically deforms in the axial direction starting from the connecting portion 24. When the spring 10 expands, the arc portions 23 deform in directions away from each other in the axial direction, thereby expanding the width of each first slit 13. When the spring 10 contracts, the arc portions 23 deform in directions approaching each other in the axial direction, thereby reducing the width of each first slit 13. The portions of each arc portion 23 that extend cantilevered in the circumferential direction from the connecting portion 24 do not elastically deform when the spring 10 expands or contracts, and therefore do not contribute to the expansion or contraction of the spring 10.

[0048] <Operation of this embodiment> The spring 10 expands and contracts as the width of the first slit 13 in the axial direction expands and contracts. At this time, the two opposing surfaces 15 that face each other across the second slit 14 move in opposite directions in the axial direction.

[0049] In the spring 10 of this embodiment, each of the two opposing surfaces 15 includes a concave surface 16. Between the two concave surfaces 16, a second region A2 is located on both sides of the first region A1 in the axial direction. A second distance d2 between the two concave surfaces 16 in the second region A2 is smaller than a first distance d1 between the two concave surfaces 16 in the first region A1. Therefore, as shown in FIG. 8 , by inserting a cylindrical rod-shaped member 30, whose diameter is the same as the imaginary circle V shown in FIG. 5 and whose movement is restricted, into the second slit 14, each of the two concave surfaces 16 is caught on the rod-shaped member 30 on both sides in the axial direction. This restricts the two opposing surfaces 15 from moving in both directions in the axial direction.

[0050] Advantages of the Present Embodiment (1) Each of the two opposing surfaces 15 that face each other across the second slit 14 includes a concave surface 16. The second slit 14 includes a first region A1 and second regions A2 located on both sides of the first region A1 in the axial direction.

[0051] According to the above configuration, by inserting the rod-shaped member 30 into the second slit 14, it is possible to suppress expansion and contraction of the spring 10 when the spring 10 is not in use. (2) The two opposing concave surfaces 16 are curved in an arc shape along the same imaginary circle V.

[0052] According to the above configuration, when inserting a cylindrical rod-shaped member 30 having the same diameter as the imaginary circle V into the second slit 14, there is no need to adjust the rotational phase of the rod-shaped member 30. Therefore, the rod-shaped member 30 can be easily inserted into the second slit 14. Therefore, expansion and contraction of the spring 10 when the spring 10 is not in use can be easily suppressed.

[0053] <Modifications> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0054] As shown in Fig. 9, the central axis C2 of the imaginary circle V may pass through a position within the second slit 14 that is offset from the center of the second slit 14 in the axial direction to one side in the axial direction. For convenience, in Fig. 9, the diameter of the imaginary circle V is illustrated as being larger than the diameter of the rod-shaped member 30. Even with this configuration, an effect similar to the above-described effect (1) can be achieved.

[0055] 10, each concave surface 16 may be recessed in a V-shape. In this case, each concave surface 16 is formed by a pair of inclined surfaces 18 that intersect with the axial direction. Even with this configuration, an effect similar to the above-described effect (1) can be achieved.

[0056] The opposing surfaces 15 are not limited to those including concave surfaces 16. The shape of the opposing surfaces 15 may be any shape as long as the opposing surfaces 15 intersect with the axial direction. For example, the opposing surfaces 15 may include a single inclined surface 19 inclined with respect to the axial direction. In this case, as shown in FIG. 11 , the two opposing inclined surfaces 19 may be parallel. Furthermore, as shown in FIG. 12 , the two opposing inclined surfaces 19 may be inclined with respect to the axial direction so as to approach each other toward one side in the axial direction. According to these configurations, by inserting a rod-shaped member 30 having the same cross-sectional shape as the second slit 14 and whose movement is restricted into the second slit 14, the two opposing surfaces 15 are caught on the rod-shaped member 30 from either side in the axial direction. This restricts the two opposing surfaces 15 from moving toward the rod-shaped member 30 in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slit 14, at least one of the extension and contraction of the spring 10 can be suppressed when the spring 10 is not in use.

[0057] As shown in FIG. 13 , the two concave surfaces 16 may be curved in an arc shape along the same imaginary circle V, centered on the central axis C2 that is perpendicular to the axial direction and passes through the first slit 13. The two concave surfaces 16 are located on the circumference of the same imaginary circle V. In this modified example, the radius of the imaginary circle V is greater than the width of the arc portion 23. With this configuration, by inserting a cylindrical rod-shaped member 30 having the same diameter as the imaginary circle V and whose movement is restricted into the second slit 14, each of the two concave surfaces 16 is caught on the rod-shaped member 30 on one side in the axial direction. This restricts the two opposing surfaces 15, which move in opposite directions in the axial direction when the spring 10 expands or contracts, from moving toward the rod-shaped member in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slit 14, the expansion and contraction of the spring 10 when it is not in use can be suppressed. This configuration also achieves an effect similar to the above-described effect (2). Note that a portion of the rod-shaped member 30 is located inside the two first slits 13 that communicate with the second slits 14. Therefore, when the spring 10 compresses, the rod-shaped member 30 comes into contact with the inner surfaces of the first slits 13, thereby suppressing the compression of the spring 10. For convenience, in Figure 13, the diameter of the imaginary circle V is shown larger than the diameter of the rod-shaped member 30.

[0058] As shown in FIG. 14 , the two concave surfaces 16 may be curved in an arc shape along two imaginary circles V of the same diameter, centered on a central axis C2 that is perpendicular to the axial direction and passes through the second slit 14. In this modified example, the two imaginary circles V are located at the same axial position but at different circumferential positions. The two imaginary circles V may be located at different axial and circumferential positions as long as the central axis C2 passes through the second slit 14. According to these configurations, by inserting a rod-shaped member 30 having the same cross-sectional shape as the second slit 14 and whose movement is restricted into the second slit 14, each of the two concave surfaces 16 is caught on the rod-shaped member 30 on both sides in the axial direction. This restricts the two opposing surfaces 15 from moving in both directions in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slit 14, expansion and contraction of the spring 10 when the spring 10 is not in use can be suppressed.

[0059] As shown in FIG. 15 , the two concave surfaces 16 may be curved in an arc shape along two imaginary circles V of the same diameter, centered on a central axis C2 that is perpendicular to the axial direction and passes through the first slit 13. In this modified example, the two imaginary circles V are located at the same axial position but at different circumferential positions. The two imaginary circles V may be located at different axial and circumferential positions as long as the central axis C2 passes through the same first slit 13. According to these configurations, by inserting a rod-shaped member 30 having the same cross-sectional shape as the second slit 14 and whose movement is restricted into the second slit 14, each of the two concave surfaces 16 is caught on the rod-shaped member 30 on one side in the axial direction. This restricts the two opposing surfaces 15, which move in opposite directions in the axial direction when the spring 10 expands or contracts, from moving toward the rod-shaped member in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slit 14, the expansion and contraction of the spring 10 can be suppressed when the spring 10 is not in use.

[0060] As shown in FIG. 16 , the two concave surfaces 16 may be curved in an arc shape along a first imaginary circle V1 and a second imaginary circle V2 having the same diameter. The first imaginary circle V1 is an imaginary circle whose center is a central axis C2 that is perpendicular to the axial direction and passes through the first slit 13. The second imaginary circle V2 is an imaginary circle whose center is a central axis C2 that is perpendicular to the axial direction and passes through the second slit 14. With this configuration, by inserting a rod-shaped member 30 having the same cross-sectional shape as the second slit 14 and whose movement is restricted into the second slit 14, the concave surface 16 along the first imaginary circle V1 is caught on the rod-shaped member 30 on one side in the axial direction. Furthermore, the concave surface 16 along the second imaginary circle V2 is caught on the rod-shaped member 30 on both sides in the axial direction. This restricts the concave surface 16 along the first imaginary circle V1 from moving toward the rod-shaped member 30 in the axial direction. Furthermore, the concave surface 16 along the second imaginary circle V2 is restricted from moving in both directions in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slit 14, it is possible to suppress expansion and contraction of the spring 10 when the spring 10 is not in use.

[0061] 17 , the two concave surfaces 16 may be curved in an arc shape along two imaginary circles V of the same diameter centered on a central axis C2 that is perpendicular to the axial direction and passes through each of the two first slits 13 that communicate with the second slits 14. According to this configuration, by inserting a rod-shaped member 30 that has the same cross-sectional shape as the second slits 14 and whose movement is restricted into the second slits 14, the two concave surfaces 16 are caught on the rod-shaped member 30 from opposite sides in the axial direction. This restricts the two opposing surfaces 15, which move in opposite directions in the axial direction when the spring 10 compresses, from moving toward the rod-shaped member 30 in the axial direction. Therefore, by inserting the rod-shaped member 30 into the second slits 14, compression of the spring 10 can be suppressed when the spring 10 is not in use.

[0062] As shown in FIG. 18 , each of the two opposing surfaces 15 may include a convex surface 17. Each convex surface 17 is continuous with the outer and inner peripheral surfaces of the arc portion 23. The convex surfaces 17 are curved in an arc shape. The second region A2 in this modified example is a region where the distance between the two opposing convex surfaces 17 is a second distance d2 that is greater than the first distance d1. The first distance d1 is the distance between the most protruding portions of the two convex surfaces 17. The second distance d2 is the distance between the portions of the two convex surfaces 17 excluding the most protruding portions. The second distance d2 increases with increasing axial distance from the first region A1. For convenience, FIG. 18 illustrates the maximum second distance d2. According to this configuration, by inserting the rod-shaped member 30, which has the same cross-sectional shape as the second slit 14 and whose movement is restricted, into the second slit 14, each of the two convex surfaces 17 is caught on the rod-shaped member 30 on both sides in the axial direction. Therefore, an effect similar to the above-mentioned effect (1) can be achieved.

[0063] As shown in FIG. 19 , one of the two opposing surfaces 15 may have a concave surface 16, and the other of the two opposing surfaces 15 may have a convex surface 17 facing the concave surface 16. The convex surface 17 is continuous with the outer and inner peripheral surfaces of the arc portion 23. The convex surface 17 is curved in an arc shape. The curvature of the convex surface 17 is the same as the curvature of the concave surface 16. That is, the distance between the concave surface 16 and the convex surface 17 in the circumferential direction is constant throughout the axial direction. With this configuration, by inserting a rod-shaped member 30 having the same cross-sectional shape as the second slit 14 and whose movement is restricted into the second slit 14, the concave surface 16 and the convex surface 17 of the two opposing surfaces 15 are caught on the rod-shaped member 30 on both sides in the axial direction. Therefore, an effect similar to the effect (1) described above can be achieved.

[0064] The plurality of slit groups 12 may be formed at intervals in the axial direction while being shifted by any angle on one side in the circumferential direction. The slit group 12 may have three or more first slits 13.

[0065] Only a portion of the opposing surface 15 may intersect with the axial direction. In other words, as long as a portion of the opposing surface 15 intersects with the axial direction, the remaining portion may be a plane extending in the axial direction.

[0066] The curvature of the concave surface 16 and the convex surface 17 in this embodiment and each modified example can be changed as appropriate. The width of the first slit 13 and the width of the arc portion 23 can be changed as appropriate. In this case, by standardizing the shape of the opposing surface 15 among multiple types of springs having different widths of the first slit 13 or the arc portion 23, the shape of the rod-shaped member 30 can be standardized.

[0067] The spring 10 does not have to be circular when viewed in the axial direction. For example, the spring 10 may have a peripheral wall 11 that is polygonal when viewed in the axial direction. The spring 10 may also have a peripheral wall 11 that is frustum-shaped and narrows toward one side in the axial direction.

[0068] The spring 10 may be made of a material other than a metal material, such as a resin material.

[0069] A1...first region A2...second region C1...central axis C2...central axis d1...first distance d2...second distance V...virtual circle V1...first virtual circle V2...second virtual circle 10...spring 11...circumferential wall 12...slit group 13...first slit 14...second slit 15...opposing surface 16...concave surface 17...convex surface 18...inclined surface 19...inclined surface 22...leaf spring portion 23...circular arc portion 24...connecting portion 30...rod-shaped member 110...spring 111...circumferential wall 112...slit group 113...first slit 114...second slit 115...opposing surface

Claims

1. A spring having an annular peripheral wall, wherein the peripheral wall has: a plurality of slit groups formed at intervals in the axial direction of the peripheral wall, each of the slit groups having a plurality of first slits extending in the circumferential direction of the peripheral wall and formed at intervals in the circumferential direction; a plurality of second slits connecting the first slits of two of the slit groups adjacent to each other in the axial direction and formed at intervals in the circumferential direction; and two opposing surfaces facing each other in the circumferential direction, with each of the second slits sandwiched between them, wherein each of the opposing surfaces intersects with the axial direction.

2. A spring as described in claim 1, wherein each of the opposing surfaces includes a concave surface, and the second slit includes a first region in which the distance between the two opposing concave surfaces is a first distance, and second regions located on both sides of the first region in the axial direction, in which the distance between the two concave surfaces is a second distance smaller than the first distance.

3. The spring according to claim 2, wherein the two concave surfaces are curved in an arc shape along the same imaginary circle whose center is a central axis that is perpendicular to the axial direction and passes through the second slit.

4. The spring according to claim 1, wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc shape along the same imaginary circle whose center is a central axis that is perpendicular to the axial direction and passes through the first slit.

5. The spring according to claim 2, wherein the two concave surfaces are curved in an arc shape along two imaginary circles of the same diameter centered on a central axis that is perpendicular to the axial direction and passes through the second slit.

6. The spring according to claim 1, wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc shape along two imaginary circles of the same diameter, centered on a central axis that is perpendicular to the axial direction and passes through the first slit.

7. The spring as described in claim 1, wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc along a first imaginary circle whose center is on a central axis that is perpendicular to the axial direction and passes through the first slit, and a second imaginary circle that is an imaginary circle of the same diameter as the first imaginary circle and whose center is on a central axis that is perpendicular to the axial direction and passes through the second slit.

8. The spring according to claim 1, wherein each of the opposing surfaces includes a concave surface, and the two opposing concave surfaces are curved in an arc shape along two imaginary circles of the same diameter centered on a central axis that is perpendicular to the axial direction and passes through each of the two first slits that communicate with the second slits.

9. The spring according to claim 1, wherein each of the opposing surfaces includes a convex surface, and the second slit includes: a first region in which the distance between the two opposing convex surfaces is a first distance; and second regions located on both sides of the first region in the axial direction, in which the distance between the two convex surfaces is a second distance that is larger than the first distance.

10. The spring according to claim 1, wherein one of the opposing surfaces includes a concave surface, the other of the opposing surfaces includes a convex surface opposing the concave surface, and the second slit includes a region in which the distance between the opposing concave surface and the opposing convex surface is constant throughout the axial direction.

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