Torsion spring

Abstract

This torsion spring has: a plurality of elements that are each rotatable about a common rotation center line, and that are arranged in the extension direction of the rotation center line; and a connection member that connects two adjacent elements. The connection member comprises: a first connection part that is connected to one of the two adjacent elements; a second connection part that is connected to the other of the two adjacent elements; and an elastic deformation part that is connected to the first connection part and the second connection part, and that elastically deforms when one of the two adjacent elements rotates relative to the other.

Description

Torsion spring

[0001] The present disclosure relates to torsion springs.

[0002] For example, Patent Document 1 discloses a torsion bar, which is a type of torsion spring.

[0003] U.S. Patent No. 7,530,584

[0004] However, when the length or cross section of the torsion spring (torsion bar) described in Patent Document 1 is limited, its torsional rigidity is determined by the material and manufacturing method. In other words, the torsion spring described in Patent Document 1 is substantially impossible to adjust in torsional rigidity, and a desired torsional rigidity cannot be obtained.

[0005] Therefore, an object of the present disclosure is to realize a torsion spring that can have a desired torsional rigidity even when the length and cross-sectional shape are limited.

[0006] In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided a torsion spring having a plurality of elements each rotatable around a common center line of rotation and aligned in the direction of extension of the center line of rotation; and a connecting member connecting two adjacent elements, wherein the connecting member has: a first connecting portion connecting one of the two adjacent elements; a second connecting portion connecting the other of the two adjacent elements; and an elastic deformation portion connected to the first connecting portion and the second connecting portion, which elastically deforms when the one of the two adjacent elements rotates relative to the other element.

[0007] According to the present disclosure, a torsion spring can have a desired torsional stiffness even when its length and cross-sectional shape are limited.

[0008] Perspective view of the torsion spring according to Embodiment 1 of the present disclosure Side view of the torsion spring according to Embodiment 1 Exploded perspective view of the torsion spring according to Embodiment 1 Partial cross-sectional view of a part of the torsion spring according to Embodiment 1 Top view of an element in the torsion spring according to Embodiment 1 Bottom view of an element in the torsion spring according to Embodiment 1 Top view of a connecting member in the torsion spring according to Embodiment 1 Perspective view showing two adjacent elements connected by one connecting member Partial perspective view corresponding to FIG. 7 Exploded perspective view for explaining the connection of two elements via one connecting member Top view showing the natural state of two adjacent elements Top view showing a state where one adjacent element is rotated +10 degrees with respect to the other element Top view showing a state where one adjacent element is rotated -10 degrees with respect to the other element Perspective view showing the torsion spring in a state where the element assembly is torsionally deformed Perspective view showing the torsion spring in a state where the element assembly is torsionally deformed in the opposite direction to FIG. 11A Perspective view of an element assembly in the torsion spring according to Embodiment 2 Exploded perspective view of the element assembly shown in FIG. 12A Partial cross-sectional view of a part of the torsion spring according to Embodiment 3 Partial cross-sectional view of a part of the torsion spring according to Embodiment 4 Partial cross-sectional view of a part of the torsion spring according to Embodiment 5 Partial cross-sectional view of a part of the torsion spring according to Embodiment 6 Partial cross-sectional view of a part of the torsion spring according to Embodiment 7 Partial cross-sectional view of a part of the torsion spring according to a modification of Embodiment 7 Perspective view showing a part of a power transmission mechanism including the torsion spring Exploded perspective view of the power transmission mechanism shown in FIG. 19A Perspective view of a torsion bar assembly including the torsion spring Exploded perspective view of the torsion bar assembly shown in FIG. 20A

[0009] A torsion spring according to one embodiment of the present disclosure comprises a plurality of elements each rotatable around a common center line of rotation and aligned in the direction of extension of the center line of rotation, and a connecting member connecting two adjacent elements, the connecting member comprising a first connecting portion connecting one of the two adjacent elements, a second connecting portion connecting the other of the two adjacent elements, and an elastic deformation portion connected to the first connecting portion and the second connecting portion and elastically deforming when one of the two adjacent elements rotates relative to the other element.

[0010] According to this aspect, the torsion spring can have a desired torsional stiffness even when its length and cross-sectional shape are limited.

[0011] For example, each of the plurality of elements may include a first engaging portion provided on a first end surface on one side in the extension direction and engaging with the first connecting portion of the connecting member, and a second engaging portion provided on a second end surface on the other side in the extension direction and engaging with the second connecting portion of the connecting member. In this case, the elastic deformation portion of the connecting member may extend in a direction intersecting the extension direction.

[0012] For example, the first engaging portion and the second engaging portion may be plural and arranged alternately at regular intervals in the circumferential direction about the rotation center line, and the first connecting portion and the second connecting portion may be plural and arranged alternately at regular intervals in the circumferential direction. In this case, the elastically deforming portion may be plural and each may extend in a meandering shape in the circumferential direction to connect to the corresponding first connecting portion and the corresponding second connecting portion.

[0013] For example, the torsion spring may further include a shaft that passes through the elements in the extension direction and supports the elements rotatably about the rotation center line.

[0014] For example, each of the plurality of elements may be supported on the shaft via a first bearing.

[0015] For example, the torsion spring may further have first and second end members connected to the elements at both ends of the plurality of elements, respectively, and the first and second end members may support the shaft rotatably about the rotation center line.

[0016] For example, one of the first and second end members may be fixed to the shaft, and the other of the first and second end members may support the shaft rotatably about the rotation center line.

[0017] For example, each of the plurality of elements may include a support portion that supports the adjacent element so that the element can rotate about the rotation center line.

[0018] For example, each of the plurality of elements may have, as the support portion, an outer circumferential surface centered on the rotation center line, and an inner circumferential surface facing the outer circumferential surface of the adjacent other element.

[0019] For example, the outer circumferential surface of each of the plurality of elements may be supported by the inner circumferential surface of the adjacent other element via a second bearing.

[0020] For example, the elements may have the same shape.

[0021] For example, the plurality of connecting members may have the same shape.

[0022] For example, the plurality of elements may include a plurality of types of elements having different shapes, and the plurality of types of elements may be arranged periodically in the extension direction.

[0023] For example, a seal may be provided between the two adjacent elements.

[0024] For example, each of the plurality of elements may include a stopper portion that limits the range of rotation of the adjacent element about the rotation center line.

[0025] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0026] (First embodiment) Fig. 1 is a perspective view of a torsion spring according to a first embodiment of the present disclosure. Fig. 2 is a side view of the torsion spring according to the first embodiment. Fig. 3 is an exploded perspective view of the torsion spring according to the first embodiment. And Fig. 4 is a partial cross-sectional view of a portion of the torsion spring according to the first embodiment.

[0027] The X-Y-Z Cartesian coordinate system shown in the figure is intended to facilitate understanding of the embodiments of the present disclosure and does not limit the embodiments of the present disclosure. The Z-axis direction indicates the extension direction of the torsion spring, the X-axis direction indicates the width direction, and the Y-axis direction indicates the depth direction.

[0028] 1 to 3, the torsion spring 10 has a plurality of elements 20 arranged in the extension direction (Z-axis direction) of the torsion spring 10, and a plurality of connecting members 22 connecting the plurality of elements 20. In the case of the first embodiment, the torsion spring 10 also has a shaft 24 that passes through the plurality of elements 20 in the extension direction of the torsion spring 10 and supports the plurality of elements 20 rotatably about a rotation center line CL that extends in the extension direction of the torsion spring 10.

[0029] In the first embodiment, the elements 20 have the same shape. Each of the elements 20 is disk-shaped and has a first end face 20a on one side in the direction in which the rotation center line CL extends (the Z-axis direction) and a second end face 20b on the other side. Each of the elements 20 has a through hole 20c that penetrates the elements in the direction in which the rotation center line CL extends and through which the shaft 24 passes. The shaft 24 passes through the through hole 20c, so that each of the elements 20 is supported by the shaft 24 so as to be rotatable about the rotation center line CL. Because the shaft 24 penetrates each of the elements 20, i.e., the through hole 20c functions as a bearing for the shaft 24, each of the elements 20 can bear a load in the radial direction.

[0030] Furthermore, the multiple elements 20 are connected via multiple connecting members 22 to form an element assembly 26. Specifically, two elements 20 adjacent to each other in the direction in which the rotation center line CL extends (the Z-axis direction) are connected via one connecting member 22. In other words, two connecting members 22 are connected to one element 20. In the case of the first embodiment, as shown in FIG. 4 , the connecting member 22 is disposed between the two elements 20 to be connected. Therefore, when there are N elements 20 (N is an integer of 2 or more), there are (N−1) connecting members 22. Next, details of the connecting members 22 and the connection of the elements 20 by the connecting members 22 will be described.

[0031] Figures 5A and 5B are top and bottom views of an element in the torsion spring according to embodiment 1. Figure 6 is a top view of a connecting member in the torsion spring according to embodiment 1. Figure 7 is a perspective view showing two adjacent elements connected by one connecting member. Figure 8 is a partial perspective view corresponding to Figure 7. Figure 9 is an exploded perspective view illustrating the connection of two elements via one connecting member.

[0032] 5A and 5B, in the first embodiment, the first end face 20a and the second end face 20b of the element 20 have the same shape. That is, the element 20 has a shape that is plane-symmetric with respect to a plane (X-Y plane) that is orthogonal to the extension direction of the rotation center line CL (Z-axis direction). In the first embodiment, the element 20 has a shape that is rotationally symmetric, specifically, three-fold symmetric, when viewed in the extension direction of the rotation center line CL.

[0033] 3, 4, and 6, in the present embodiment, the multiple connecting members 22 have the same shape and are made of an elastic material. The connecting members 22 are thin, annular members that have a rotationally symmetric, specifically, six-fold symmetric shape when viewed in the direction in which the rotation center line CL extends (the Z-axis direction).

[0034] 6 and 9 , the connecting member 22 includes a plurality of first connecting portions 22a connecting one element 20 (20A) of two elements 20 adjacent in the direction in which the rotation center line CL extends (the Z-axis direction), and a plurality of second connecting portions 22b connecting the other element 20 (20B). The first connecting portions 22a are provided on the connecting member 22 at angular intervals of 120 degrees in the circumferential direction R of the rotation center line CL. The second connecting portions 22b are provided on the connecting member 22 at angular intervals of 120 degrees in the circumferential direction R relative to the rotation center line CL. That is, the plurality of first and second connecting portions 22a, 22b are alternately arranged in the circumferential direction R at angular intervals of 60 degrees.

[0035] In the connecting member 22, the first connecting portion 22a and the second connecting portion 22b are connected via an elastically deforming portion 22c. The elastically deforming portion 22c is a portion of the connecting member 22 that is easily elastically deformed, and extends from the first connecting portion 22a toward the second connecting portion 22b. In the case of the first embodiment, the elastically deforming portion 22c extends in a meandering shape in the circumferential direction R relative to the rotation center line CL so as to be easily elastically deformed in the circumferential direction R, and is connected to the corresponding first connecting portion 22a and second connecting portion 22b.

[0036] In the first embodiment, as shown in Figures 5A, 5B, and 9, a plurality of first engaging portions 20d that respectively engage with a plurality of first connecting portions 22a of the connecting member 22 are provided on the first end face 20a of the element 20 (20A). Also, second engaging portions 20e that engage with a plurality of second connecting portions 22b of the connecting member 22 are provided on the second end face 20b of the element 20 (20B). In the first embodiment, the first engaging portions 20d are provided on the first end face 20a at angular intervals of 120 degrees in the circumferential direction R relative to the rotation center line CL. Also, the second engaging portions 20e are provided on the second end face 20b at angular intervals of 120 degrees in the circumferential direction R. In the case of this embodiment 1, the element 20 has a plane-symmetric shape with the plane (X-Y plane) perpendicular to the extension direction of the rotation center line CL (Z-axis direction) as the plane of symmetry, so the first engagement portion 20d and the second engagement portion 20e are aligned in the extension direction of the rotation center line CL.

[0037] In the first embodiment, the first and second engagement portions 20d, 20e are pins that protrude from the first and second end faces 20a, 20b in the direction in which the rotation center line CL extends (the Z-axis direction). First and second engagement holes 22d, 22e that engage with the pin-shaped first and second engagement portions 20d, 20e are formed in the first and second connecting portions 22a, 22b of the connecting member 22. In the first embodiment, the first and second engagement holes 22d, 22e are square holes, and the first and second engagement portions 20d, 20e are square prism-shaped. Note that FIG. 8 shows a state in which the first engagement portion 20d of one element 20 (20A) is engaged with the first engagement hole 22d of the connecting member 22.

[0038] It is preferable that the cross-sectional shape of the first and second engaging portions 20d, 20e be a non-circular shape, such as a triangular shape, a Y-shape, or a T-shape, as in the present embodiment 1. In addition, it is preferable that the first and second engaging holes 22d, 22e that engage with the first and second engaging portions 20d, 20e have a shape that prevents the first and second connecting portions 22a, 22b from rotating around the first and second engaging portions 20d, 20e.

[0039] Alternatively, for example, if the cross-sectional shapes of the first and second engaging portions 20d, 20e are circular, the first and second connecting portions 22a, 22b rotate around the first and second engaging portions 20d, 20e, respectively. This rotation generates friction between the first and second engaging holes 22d, 22e of the first and second connecting portions 22a, 22b and the first and second connecting portions 22a, 22b. This rotation and friction may cause the deformation behavior of multiple elastically deforming portions 22c in a single connecting member 22 to differ, and / or the deformation behavior of multiple connecting members 22 may differ. As a result, the element assembly 26 may have different amounts of twist in different parts. Furthermore, due to the friction, it takes time for the elastically deformed elastically deforming portions 22c to return to their original state (natural state).

[0040] Therefore, in this embodiment, the first and second engagement holes 22d, 22e are square holes, and the first and second engagement portions 20d, 20e are square prism-shaped, which suppresses rotation of the first and second connecting portions 22a, 22b, thereby suppressing friction loss due to rotation and, as a result, making the deformation behavior of the multiple elastic deformation portions 22c in the multiple connecting members 22 substantially uniform.

[0041] In the first embodiment, as shown in FIG. 6 , in the connecting member 22, the first and second connecting portions 22a, 22b are alternately arranged at 60-degree intervals in the circumferential direction R. As shown in FIG. 5A , the first engaging portions 20d of the element 20 (20A) that engage with the first connecting portions 22a are provided on the first end face 20a at 120-degree intervals in the circumferential direction R. As shown in FIG. 5B , the second engaging portions 20e of the element 20 (20B) that engage with the second connecting portions 22b are also provided on the second end face 20b at 120-degree intervals in the circumferential direction R. In each element 20, the first and second engaging portions 20d, 20e are arranged in the direction in which the rotation center line CL extends (the Z-axis direction). Therefore, two adjacent elements 20 (20A, 20B) connected to one connecting member 22 have different rotational postures. Specifically, the two elements 20 (20A, 20B) are connected to the connecting member 22 in different rotational postures rotated by 60 degrees around the rotation center line CL relative to each other when viewed in the direction in which the rotation center line CL extends (Z-axis direction). That is, the first engagement portion 20d of one element 20 (20A) and the second engagement portion 20e of the other element 20 (20B) connected to one connecting member 22 are arranged alternately at angular intervals of 60 degrees in the circumferential direction R when viewed in the direction in which the rotation center line CL extends.

[0042] Fig. 10A is a top view showing two adjacent elements in their natural state, Fig. 10B is a top view showing one adjacent element rotated +10 degrees relative to the other adjacent element, and Fig. 10C is a top view showing one adjacent element rotated -10 degrees relative to the other adjacent element.

[0043] 10A, 10B, and 10C show two elements 20 (20A, 20B) that are connected to one connecting member 22 and are adjacent to each other in the direction in which the rotation center line CL extends (the Z-axis direction). The other element 20 (20B) is located closer to the viewer in the drawing than the one element 20 (20A). Therefore, the second engaging portion 20e of the other element 20 (20B), which engages with the second connecting portion 22b of the connecting member 22, is not visible.

[0044] 10A shows two elements 20 (20A, 20B) adjacent to each other in the direction in which the rotation center line CL extends (the Z-axis direction) in their natural state. Specifically, the first engagement portion 20d of one element 20 (20A) and the second engagement portion 20e of the other element 20 (20B) are alternately arranged at a constant angular interval (60 degrees) in the circumferential direction R when viewed in the direction in which the rotation center line CL extends. At this time, the connecting member 22 is also in its natural state, with the first and second connecting portions 22a, 22b alternately arranged at a constant angular interval (60 degrees) in the circumferential direction R. In other words, the connecting member 22 is not substantially elastically deformed.

[0045] 10B and 10C, when torque T1 or torque T2 (torque in the opposite direction to T1) is applied to the other element 20 (20B), the other element 20 (20B) rotates around the rotation center line CL relative to the one element 20 (20A). As a result, the connecting member 22 connecting these elements 20 (20A, 20B) elastically deforms.

[0046] Specifically, due to the rotation of the other element 20 (20B), the second connecting portion 22b of the connecting member 22, which engages with the second engaging portion 20e of the other element 20 (20B), is displaced in the circumferential direction R. In contrast, the first connecting portion 22a of the connecting member 22, which engages with the first engaging portion 20d of one element 20 (20A), is not displaced. As a result, the elastically deforming portion 22c, which is connected to the displaced second connecting portion 22b and the non-displaced first connecting portion 22a, undergoes compressive deformation, which reduces its length in the circumferential direction R, or tensile deformation, which increases its length in the circumferential direction R. That is, the elastically deforming portion 22c, which is connected to the first connecting portion 22a and the second connecting portion 22b, whose spacing in the circumferential direction R has been reduced, is compressively deformed, and the elastically deforming portion 22c, which is connected to the first connecting portion 22a and the second connecting portion 22b, whose spacing in the circumferential direction R has been increased, is tensilely deformed.

[0047] In the first embodiment, the elastic deformation portion 22c is located on the outer side of the first and second connecting portions 22a and 22b as shown in Fig. 6. Alternatively, the elastic deformation portion 22c may be located on the inner side of the first and second connecting portions 22a and 22b.

[0048] 10B and 10C, when the application of torque T1 or torque T2 to the other element 20 (20B) is released while the connecting member 22 is elastically deformed, the restoring force of the connecting member 22 causes the other element 20 (20B) to rotate in the circumferential direction. As a result, as shown in FIG. 10A, the two elements 20 (20A, 20B) adjacent to each other in the direction of extension of the rotation center line CL (Z-axis direction) return to their natural state. The connecting member 22 also returns to its natural state, not being elastically deformed.

[0049] In the first embodiment, the rotation range of one element 20 (20B) relative to the other element 20 (20A) of two elements 20 adjacent to each other in the direction in which the rotation center line CL extends (the Z-axis direction) is limited to a predetermined angular range. In the first embodiment, as shown in Figures 10A to 10C, the rotation range is limited to an angular range of ±10° from the natural state.

[0050] In the first embodiment, each element 20 is provided with a stopper portion that limits the rotation of adjacent elements 20 about the rotation center line CL. In the first embodiment, as shown in FIGS. 5A, 5B, and 9, a plurality of fan-shaped first recesses 20f are provided on the first end face 20a of each element 20 as part of the stopper portion. The plurality of first recesses 20f are aligned in the circumferential direction R at regular angular intervals. A pair of first protrusions 20g is provided between the plurality of first recesses 20f as part of the stopper portion. A plurality of fan-shaped second recesses 20h are provided on the second end face 20b of each element 20 as part of the stopper portion. A pair of second protrusions 20i is provided between the plurality of second recesses 20h as part of the stopper portion. In the first embodiment, the first recess 20f and the second recess 20h are symmetrical with respect to a plane (X-Y plane) perpendicular to the direction in which the rotation center line CL extends (the Z-axis direction). Similarly, the first protrusion 20g and the second protrusion 20i are symmetrical with respect to a plane.

[0051] As shown in FIG. 9 , in two adjacent elements 20 (20A, 20B) connected by one connecting member 22, the pair of first protrusions 20g of one element 20 (20A) is disposed in the second recess 20h of the other element 20 (20B), while the pair of second protrusions 20i of the other element 20 (20B) is disposed in the first recess 20f of the one element 20 (20A). As a result, the movement of the pair of first protrusions 20g of one element 20 (20A) in the circumferential direction R is restricted to the second recess 20h, while the movement of the pair of second protrusions 20i of the other element 20 (20B) in the circumferential direction R is restricted to the first recess 20f. As a result, the rotation ranges of the two adjacent elements 20 (20A, 20B) connected by one connecting member 22 are restricted relative to each other. This prevents the connecting member 22 from being damaged due to excessive deformation.

[0052] In the first embodiment, as shown in Fig. 4, each of the multiple elements 20 is in contact with the adjacent elements 20. Specifically, as shown in Fig. 9, an annular protrusion 20j is provided on the outer periphery of the first end face 20a of each element 20, and an annular protrusion 20k is provided on the outer periphery of the second end face 20b. These protrusions 20j, 20k are in contact with each other.

[0053] In this way, the elastically deformable connecting member 22 connects two elements 20 adjacent to each other in the direction in which the rotation center line CL extends (the Z-axis direction). Therefore, one element 20 rotates elastically relative to the adjacent element 20. As a result, the element assembly 26 shown in FIG. 1 , which is an assembly of multiple elements 20, is elastically torsionally deformable.

[0054] In the first embodiment, as shown in FIGS. 1 , 2 , and 3 , first and second end members 28, 30 are connected to both ends of the element assembly 26, i.e., to each of the elements 20 at both ends of the plurality of elements 20. Specifically, the first and second end members 28, 30 are connected to the corresponding elements 20 so as to prevent rotation about the rotation center line CL relative to the corresponding elements 20. In the first embodiment, the first and second end members 28, 30 have fan-shaped protrusions 28a, 30a that engage with the fan-shaped first and second recesses 20f, 20h of the element 20, as shown in FIG. 3 . In the first embodiment, the first and second end members 28, 30 are substantially cylindrical and support the shaft 24 so as to be rotatable about the rotation center line CL. Therefore, the element assembly 26 is torsionally deformed via the first and second end members 28, 30.

[0055] 11A and 11B are perspective views showing the torsion spring in a state where the element assembly is torsionally deformed. Note that Fig. 11A and Fig. 11B show element assemblies 26 with different twisting directions.

[0056] 11A and 11B , when torque T1 or torque T2 (torque in the opposite direction to T1) is applied to the first end member 28 of the torsion spring 10 about the rotation center line CL, the first end member 28 rotates relative to the second end member 30 about the rotation center line CL, causing torsional deformation of the element assembly 26. That is, each of the multiple elements 20 in the element assembly 26 rotates relative to the adjacent elements 20 on the side of the second end member 30, causing torsional deformation of the entire element assembly 26.

[0057] According to the first embodiment, even if the length and cross-sectional shape are limited, the torsion spring can have a desired torsional rigidity.

[0058] For example, the torsional rigidity of the torsion spring 10 can be adjusted by fabricating the multiple connecting members 22 from multiple types of materials with different elastic moduli. Additionally or alternatively, the torsional rigidity of the torsion spring 10 can be adjusted by, for example, adjusting the extension length or width of the meander-shaped elastic deformation portion 22c of the connecting member 22. In other words, the torsional rigidity of the torsion spring 10 can be easily adjusted by changing at least one of the multiple connecting members 22. Furthermore, because the connecting members 22 are thin, multiple connecting members 22 can be attached to the elements 20 in a stacked manner. In other words, the torsional rigidity can also be adjusted by increasing or decreasing the number of connecting members 22 attached to one element 20.

[0059] (Embodiment 2) In the case of the above-described Embodiment 1, the multiple elements 20 constituting the element assembly 26 in the torsion spring 10 have the same shape. Therefore, as shown in Figures 1 and 2, the element assembly 26 is columnar and extends in the direction of extension of the rotation center line CL (Z-axis direction). Embodiment 2 differs from the above-described Embodiment 1 in that the shapes of the multiple elements constituting the element assembly are different. Therefore, Embodiment 2 will be described focusing on the differences from the above-described Embodiment 1.

[0060] Fig. 12A is a perspective view of an element assembly in a torsion spring according to embodiment 2. Fig. 12B is an exploded perspective view of the element assembly shown in Fig. 12A.

[0061] 12A and 12B, the element assembly 126 of the torsion spring according to the second embodiment is made up of multiple types of elements 120-1 to 120-16 that are different in shape. Specifically, the element assembly 126 is frustum-shaped. Therefore, each of the multiple types of elements 120-1 to 120-16 has a frustum shape that is different in size. However, the multiple connecting members 122 that connect adjacent elements have the same shape.

[0062] In the second embodiment, the multiple connecting members 122 have the same shape. Therefore, the portions of the multiple types of elements 120-1 to 120-6 that are connected to the first and second connecting portions of the connecting member 122 also have the same shape. Therefore, it is possible to arrange the multiple types of elements 120-1 to 120-16 randomly so that the element assembly 126 does not have a frustum shape. In other words, as long as the multiple connecting members are the same and the portions of the multiple elements that are connected to the first and second connecting portions of the connecting members are the same, the multiple elements do not need to have the same shape and can also be arranged without any regularity (for example, periodicity).

[0063] According to the second embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0064] (Embodiment 3) In the case of the above-described embodiment 1, the elements 20 of the torsion spring 10 are directly rotatably supported on the shaft 24. In the case of embodiment 3, the elements are indirectly supported on the shaft.

[0065] FIG. 13 is a partial cross-sectional view of a portion of a torsion spring according to the third embodiment.

[0066] 13, the element assembly 226 in the torsion spring according to the third embodiment is composed of two types of elements 220-1 and 220-2 that are different in shape. The elements 220-1 and 220-2 are arranged periodically, specifically alternately, in the direction in which the rotation center line CL extends (the Z-axis direction). In other words, one connecting member 220 connects the elements 220-1 and 220-2 that are different in shape.

[0067] Furthermore, bearings 232, specifically bearings, are disposed between the shaft 224 and each of the plurality of elements 220-1 and 220-2. As a result, each of the plurality of elements 220-1 and 220-2 is rotatably supported on the shaft 224 via the bearings 232. Furthermore, cylindrical spacers 234 are provided between the bearings 232. The bearings 232 are not limited to bearings, and may be bushings. Furthermore, since the plurality of elements 220-1 and 220-2 are supported on the shaft 224 via the bearings 232, they are not in direct contact with each other (the elements do not support each other). This allows the plurality of elements 220-1 and 220-2 to rotate more easily than if they were in contact with each other. Furthermore, each of the plurality of elements 220-1 and 220-2 also rotates more easily relative to the shaft 224. Compared to the first embodiment described above, the elements 220-1 and 220-2 can be rotated rapidly and continuously relative to the shaft 224. That is, the shaft 224 can be rotated freely when viewed from the elements 220-1 and 220-2.

[0068] According to the third embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0069] The bearing can also be used when a plurality of elements have the same shape as in the first embodiment described above.

[0070] (Fourth Embodiment) The fourth embodiment is an improved version of the third embodiment.

[0071] FIG. 14 is a partial cross-sectional view of a portion of a torsion spring according to the fourth embodiment.

[0072] 14, the torsion spring according to the fourth embodiment includes two types of elements 220-1 and 220-2 having different shapes, as well as at least one element 220-3 that is different from the elements 220-1 and 220-2. Like elements 220-1 and 220-2, element 220-3 is rotatably supported on shaft 224 via bearing 232. Element 220-3 is also connected to adjacent element 220-1 via connecting member 222. Element 220-3 is also supported by member 238 outside the torsion spring via bearing 236 so as to be rotatable about rotation center line CL.

[0073] Such an element 220-3 suppresses deflection of the torsion spring when the torsion spring is long in the direction in which the rotation center line CL extends (Z-axis direction) and / or when the rotation center line CL is inclined with respect to the vertical direction.

[0074] According to the fourth embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0075] (Embodiment 5) In the case of the above-described embodiment 1, the multiple elements 20 are rotatably supported by the shaft 24. This allows each of the multiple elements 20 to rotate around a common rotation center line CL. In this embodiment 5, unlike the above-described embodiment 1, the multiple elements are not supported by the shaft.

[0076] FIG. 15 is a partial cross-sectional view of a portion of a torsion spring according to the fifth embodiment.

[0077] As shown in FIG. 15 , the torsion spring according to the fifth embodiment does not have a shaft. Therefore, since each of the multiple elements 320-1, 320-2, and 320-3 rotates around a common rotation center line CL, adjacent elements connected via connecting member 322 are rotatably supported. Specifically, each of the multiple elements 320-1, 320-2, and 320-3 has a support portion that supports the adjacent element rotatably around the rotation center line CL. In the case of the fifth embodiment, one of the adjacent elements is rotatably supported by the other element via bearing 340. Specifically, each of the multiple elements 320-1, 320-2, and 320-3 has, as a support portion, outer peripheral surfaces 320-1a, 320-2a, and 320-3a that are centered on the rotation center line CL. Each of the elements 320-1 and 320-2 has inner peripheral surfaces 320-1b and 320-2b that face the outer peripheral surfaces of the other elements as support portions. The inner peripheral surfaces 320-1b and 320-2b of the elements 320-1 and 320-2 support the outer peripheral surfaces 320-1a, 320-2a, and 320-3a of the adjacent elements via bearings 340.

[0078] In the fifth embodiment, the inner and outer peripheral surfaces of the support portions of the elements that support adjacent elements support each other via bearings, but they may also support each other by direct contact. In the fifth embodiment, the support portions of the elements are cylindrical inner and outer peripheral surfaces, but this is not limiting. For example, the support portions of the elements may be truncated cone-shaped inner and outer peripheral surfaces. Furthermore, for example, the element support portions may be arc-shaped guide grooves provided on the first end face and guide pins provided on the second end face that are guided by the guide grooves of the adjacent elements.

[0079] According to the fifth embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0080] In the fifth embodiment, since the torsion spring does not have a shaft, it has an internal space that penetrates each of the multiple elements 320-1, 320-2, and 320-3 in the direction of extension of the rotation center line CL (Z-axis direction). An external member of the torsion spring, such as a cable or a power transmission shaft, may pass through this internal space. Furthermore, since the multiple elements support each other rotatably, they do not need to have a through hole.

[0081] Sixth Embodiment The sixth embodiment is a configuration in which the third and fifth embodiments described above are partially combined.

[0082] FIG. 16 is a partial cross-sectional view of a portion of a torsion spring according to a sixth embodiment.

[0083] 16 , in the torsion spring according to the sixth embodiment, each of the plurality of elements 420-1, 420-2 is rotatably supported on a shaft 424 via a bearing 432. Adjacent elements 420-1, 420-2, which are connected via a connecting member 422, rotatably support each other via a bearing 440.

[0084] According to the sixth embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0085] Seventh Embodiment The seventh embodiment is an improved version of the third embodiment.

[0086] FIG. 17 is a partial cross-sectional view of a portion of a torsion spring according to the seventh embodiment.

[0087] As shown in Figure 17, in the torsion spring according to the seventh embodiment, a seal is provided between adjacent elements 220-1 and 220-2. In the case of the seventh embodiment, the seal is a labyrinth seal, and is composed of an annular recess 220-1a formed in element 220-1 and an annular protrusion 220-2a formed in element 220-2 and housed in recess 220-1a. This labyrinth seal prevents foreign matter from entering between elements 220-1 and 220-2. In order to further prevent foreign matter from entering, positive pressure may be supplied to the gap between elements 220-1 and 220-2 inside the labyrinth seal.

[0088] Furthermore, the seal is not limited to a labyrinth seal.

[0089] FIG. 18 is a partial cross-sectional view of a portion of a torsion spring according to a modified example of the seventh embodiment.

[0090] 18, in the torsion spring according to the modified example of the seventh embodiment, a seal member 542 is provided between adjacent elements 220-1 and 220-2. The seal member 542 is an annular member made of an elastic material and has a V-shaped cross section. The seal member 542 directly contacts the elements 220-1 and 220-2 to provide a seal between them.

[0091] According to the seventh embodiment, similar to the first embodiment described above, even if the length and cross-sectional shape are limited, the torsion spring can have the desired torsional rigidity.

[0092] Up to this point, the torsion spring according to the present disclosure has been described using a number of embodiments. Next, examples of applications of the torsion spring will be described.

[0093] Fig. 19A is a perspective view showing a part of a power transmission mechanism including a torsion spring, and Fig. 19B is an exploded perspective view of the power transmission mechanism shown in Fig. 19A.

[0094] 19A and 19B, the power transmission mechanism 600 includes a torsion spring 10, a first timing pulley 652 fixed to the first end member 28 of the torsion spring 10, a first timing belt 654 suspended on the first timing pulley 652, a second timing pulley 656 fixed to the second end member 30, and a second timing belt 658 suspended on the second timing pulley 656. Note that both ends of the shaft 24 of the torsion spring 10 are supported by, for example, a casing (not shown) of the power transmission mechanism 600.

[0095] According to this power transmission mechanism 600, when the first timing belt 654 rotates, the element assemblies 26 of the torsion springs 10 undergo torsional deformation, and power is transmitted from the first timing belt 654 to the second timing belt 658 via the torsion springs 10. In the power transmission mechanism 600, the element assemblies 26 of the torsion springs 10 can function as a return mechanism, and can also serve to absorb shock and control torque through preload. Furthermore, the torsion springs 10 can undergo torsional deformation even when rotated. This makes it possible to actively control the flexibility of the power transmission path and to preset the magnitude of the reaction force when the constraint on torsional deformation is released.

[0096] 20A and 20B are perspective and exploded views of a torsion bar assembly including a torsion spring, respectively.

[0097] As shown in Figures 20A and 20B, the torsion bar assembly 700 includes a torsion spring 710 and an arm 760 fixed to one end 724a of a shaft 724 of the torsion spring 710. The element 720, first end member 728, and second end member 730 of the torsion spring 710 shown in Figures 20A and 20B differ in shape from the element 20, first end member 28, and second end member 30 of the torsion spring 10 according to the first embodiment, but are substantially identical in function. However, unlike the torsion spring 10, the other end 724b of the shaft 724 is fixed to the first end member 728. The second end member 730 is fixed non-rotatably, for example, to the frame of the vehicle on which the torsion bar assembly 700 is mounted. The second end member 730 rotatably supports the shaft 724.

[0098] In this torsion bar assembly 700, when the arm 760 rotates about the rotation center line CL, the element assembly 726 is torsionally deformed via the shaft 724. That is, elastic energy is stored in the element assembly 726. Note that a torsion bar may be used as the shaft 724. In this case, when storing the same amount of elastic energy, the torsion bar assembly 700 will be shorter than a single torsion bar.

[0099] Although the torsion spring according to the present disclosure has been described above using a number of embodiments, the torsion spring according to the present disclosure is not limited to these embodiments.

[0100] For example, in the case of the first embodiment described above, as shown in Figures 2 and 3, the first and second end members 28, 30 are connected to the elements 20 at both ends of the element assembly 26. That is, the first and second end members 28, 30 and the elements 20 at both ends of the element assembly 26 are separate members. However, the embodiment of the present disclosure is not limited to this. The first and second end members 28, 30 and the elements 20 at both ends of the element assembly 26 may be integrated as a single component. Furthermore, the elements at both ends of the element assembly may themselves be the first and second end members.

[0101] In the first embodiment described above, as shown in FIG. 9 , the element 20 is provided with first and second pin-shaped engagement portions 20d and 20e, and the first and second connecting portions 22a and 22b of the connecting member 22 are provided with first and second engagement holes 22d and 22e that engage with the pin-shaped first and second engaging portions 20d and 20e. However, the embodiments of the present disclosure are not limited to this. For example, the element may be provided with engagement holes as the first and second engagement portions, and the first and second connecting portions of the connecting member may be provided with pins that engage with the engagement holes. Furthermore, the method of connecting the first and second connecting portions of the connecting member to the element is not limited to "engagement." For example, the first and second connecting portions of the connecting member may be fixed to the element, respectively, via another member such as a screw. Note that the connection between the first and second connecting portions of the connecting member and the element may be detachable or non-detachable. In the case where the elements are not detachable, for example, one element and a connecting member that connects to the element via a first connecting portion may be integrated into one component. In this case, a second connecting portion of the connecting member integrated with one element connects to another element. The element and the connecting member can be integrated by being made of the same material, by two-color molding, or by insert molding the connecting member made of a metal material into an element made of a resin material.

[0102] Furthermore, in the case of the first embodiment described above, the connecting member 22 connecting two adjacent elements 20 is a single member, and is annular as shown in Fig. 6. However, the embodiment of the present disclosure is not limited to this. For example, the two adjacent elements may be connected via two C-shaped connecting members.

[0103] Furthermore, in the case of the first embodiment described above, as shown in FIG. 3 , the elements 20 and the connecting members 22 are alternately arranged in the direction of extension of the rotation center line CL (the Z-axis direction). However, the embodiments of the present disclosure are not limited to this. For example, some elements may be rotatably engaged with adjacent elements without being connected via a connecting member. In this case, for example, an element may be provided with an arc-shaped cam groove, and an adjacent element may be provided with a cam follower such as a pin that can move within the cam groove.

[0104] Additionally, in the first embodiment described above, as shown in FIG. 6 , the elastic deformation portions 22 c of the connecting member 22 extend in a meandering pattern in the circumferential direction R relative to the rotation center line CL. However, the elastic deformation portions of the connecting member according to the embodiment of the present disclosure are not limited to this. For example, multiple first connecting portions may be arranged in the circumferential direction on the central side, multiple second connecting portions may be arranged in the circumferential direction on the outer periphery, and the elastic deformation portions connecting corresponding first connecting portions and second connecting portions may extend in a direction that includes at least a radial component relative to the rotation center line CL. In other words, the elastic deformation portions only need to extend in a direction that allows elastic deformation when the two connecting elements rotate relative to each other.

[0105] Additionally, in the case of the first embodiment described above, the elements 20 of the torsion spring 10 are rotatably supported on the solid shaft 24. Alternatively, the elements 20 may be rotatably supported on a hollow shaft, for example, a pipe. Alternatively, the elements may be housed in a pipe, with the outer circumferential surface of each element slidably supported on the inner circumferential surface of the pipe.

[0106] Furthermore, in the case of the above-described first embodiment, the element 20 has a circular shape when viewed in the direction of extension of the rotation center line CL (Z-axis direction) as shown in FIGS. 5A and 5B , and has multiple hexagonal prism-shaped protrusions on its outer circumferential surface as shown in FIGS. 1 and 2 . However, the outer circumferential portion of the element according to the embodiment of the present disclosure is not limited to this. For example, the shape of the element 20 viewed in the direction of extension of the rotation center line CL may be, for example, non-circular, such as a regular hexagon. Furthermore, for example, the outer circumferential surface of the element may be provided with a pattern that is smooth. In other words, the outer circumferential portion of the element is characterized so that the torsional deformation of the element assembly can be visually recognized.

[0107] Note that an arm, lever, gear, pulley, etc. for transmitting force to another member may be provided on the outer periphery of some elements of the torsion spring. For example, an arm may be attached to the central element 20 of the torsion spring 10 in the power transmission mechanism 600 shown in Figures 19A and 19B.

[0108] Therefore, the embodiment of the present disclosure does not limit the outer periphery of the element in the torsion spring, and the outer periphery of the element can be variously changed depending on the application of the torsion spring.

[0109] That is, a torsion spring according to an embodiment of the present disclosure, in a broad sense, comprises a plurality of elements each rotatable around a common center line of rotation and aligned in the direction of extension of the center line of rotation, and a connecting member connecting two adjacent elements, wherein the connecting member comprises a first connecting portion connecting one of the two adjacent elements, a second connecting portion connecting the other of the two adjacent elements, and an elastic deformation portion connected to the first connecting portion and the second connecting portion and elastically deforming when one of the two adjacent elements rotates relative to the other element.

[0110] By appropriately combining any of the above-described embodiments and various modifications, it is possible to achieve the effects of each of the embodiments and modifications.

[0111] Although the present disclosure has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various variations and modifications will be apparent to those skilled in the art. Such variations and modifications should be understood to be included within the scope of the present disclosure as defined by the appended claims, unless they depart therefrom. Furthermore, changes in the combination and order of elements in each embodiment may be made without departing from the scope and spirit of the present disclosure.

[0112] The present disclosure is applicable to torsion springs used in a variety of applications.

Claims

1. A torsion spring comprising: a plurality of elements each rotatable around a common center line of rotation and aligned in the direction of extension of the center line of rotation; and a connecting member connecting two adjacent elements, wherein the connecting member comprises: a first connecting portion connecting one of the two adjacent elements; a second connecting portion connecting the other of the two adjacent elements; and an elastic deformation portion connected to the first connecting portion and the second connecting portion, which elastically deforms when the one of the two adjacent elements rotates relative to the other.

2. A torsion spring as described in claim 1, wherein each of the plurality of elements comprises a first engagement portion provided on a first end face on one side of the extension direction and engaging with the first connecting portion of the connecting member, and a second engagement portion provided on a second end face on the other side of the extension direction and engaging with the second connecting portion of the connecting member, and the elastic deformation portion of the connecting member extends in a direction intersecting the extension direction.

3. A torsion spring as described in claim 2, wherein there are a plurality of said first engaging portions and a plurality of said second engaging portions, which are arranged alternately at regular intervals in the circumferential direction relative to said rotation center line; there are a plurality of said first connecting portions and a plurality of said second connecting portions, which are arranged alternately at regular intervals in the circumferential direction; and there are a plurality of said elastically deforming portions, which each extend in a meandering pattern in the circumferential direction and connect to the corresponding first connecting portion and second connecting portion.

4. The torsion spring according to claim 1, further comprising a shaft that passes through said plurality of elements in said extension direction and supports said plurality of elements rotatably about said rotation center line.

5. The torsion spring according to claim 4, wherein each of said plurality of elements is supported on said shaft via a first bearing.

6. The torsion spring according to claim 4, further comprising first and second end members connected to elements at both ends of said plurality of elements, said first and second end members supporting said shaft so as to be rotatable about said rotation center line.

7. A torsion spring as set forth in claim 4, further comprising first and second end members connected to elements at both ends of said plurality of elements, one of said first and second end members being fixed to said shaft, and the other of said first and second end members supporting said shaft for rotation about said rotation center line.

8. A torsion spring according to claim 1, wherein each of said plurality of elements has a support portion that supports the adjacent element so that it can rotate about the rotation center line.

9. A torsion spring as described in claim 8, wherein each of the plurality of elements has, as the support portion, an outer peripheral surface centered on the rotation center line and an inner peripheral surface facing the outer peripheral surface of another adjacent element.

10. A torsion spring according to claim 9, wherein the outer peripheral surface of each of the plurality of elements is supported by the inner peripheral surface of an adjacent one of the elements via a second bearing.

11. The torsion spring of claim 1, wherein said elements have the same shape.

12. The torsion spring of claim 1, wherein said plurality of connecting members have the same shape.

13. The torsion spring according to claim 1, wherein the plurality of elements include a plurality of types of elements having different shapes, and the plurality of types of elements are arranged periodically in the extension direction.

14. The torsion spring according to claim 1, wherein a seal is provided between the two adjacent elements.

15. A torsion spring according to claim 1, wherein each of the plurality of elements is provided with a stopper portion that limits the range of rotation of the adjacent element about the rotation center line.

Images