Torsional damper

Abstract

To reduce torsional vibration and flexural vibration of a shaft with a simple configuration.SOLUTION: A torsional damper comprises a hub fixed to a shaft, an annular vibration ring along an outer periphery of the hub, and a plurality of elastic parts fitted between the hub and the vibration ring. The plurality of elastic parts is spaced apart in a circumferential direction, and a plurality of cavity parts is provided due to the spacing between the hub and the vibration ring.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to torsional dampers. [Background technology]

[0002] Torsional dampers that reduce vibrations generated in shafts such as crankshafts provided in internal combustion engines have been known. For example, Patent Document 1 discloses a damper device that includes a torsional damper that reduces torsional vibrations of the crankshaft and a bending damper that reduces bending vibrations of the crankshaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-108911 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology described in Patent Document 1, the torsional damper and the bending damper are installed separately, which poses a problem of making the configuration complicated.

[0005] In consideration of the above circumstances, an object of the present disclosure is to reduce torsional vibration and bending vibration of a shaft with a simple configuration. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the torsional damper disclosed herein comprises a hub fixed to a shaft, an annular vibration ring that follows the outer periphery of the hub, and a plurality of elastic parts that are fitted between the hub and the vibration ring, the plurality of elastic parts being arranged at intervals from one another in the circumferential direction, and a plurality of gaps formed by the intervals between the hub and the vibration ring. [Effects of the Invention]

[0007] The present disclosure makes it possible to reduce both torsional vibration and bending vibration of a shaft with a simple configuration. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a torsional damper according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 10 is a cross-sectional view of a torsional damper according to a second embodiment. [Figure 5] FIG. 10 is a cross-sectional view of a torsional damper according to a first modified example. [Figure 6] FIG. 10 is a plan view of a torsional damper according to a second modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. The dimensions and scale of each part in the drawings may differ from those of the actual parts, and some parts are shown schematically to facilitate understanding. The scope of the present disclosure is not limited to these embodiments unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0010] 1. First embodiment FIG. 1 is a plan view of a torsional damper 100 according to the first embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view taken along line BB in FIG. 1. The torsional damper 100 is a dynamic vibration absorber that reduces vibrations generated in a shaft 200, such as a crankshaft, provided in an internal combustion engine such as a reciprocating engine. The shaft 200 rotates about a central axis AX. Torsional vibrations and bending vibrations can occur in the shaft 200 about the central axis AX. In FIGS. 1 to 3, the shaft 200 is simply illustrated by a two-dot chain line.

[0011] As shown in FIGS. 1 to 3, the torsional damper 100 includes a hub 10 , two damper rubbers 30 , and a vibration ring 20 .

[0012] Each part of the torsional damper 100 will be described below in order. In the following description, a direction along an imaginary circle centered on the central axis AX is referred to as the "circumferential direction," a direction perpendicular to the central axis AX is referred to as the "radial direction," and a direction along the central axis AX is referred to as the "axial direction." An axis perpendicular to the central axis AX and parallel to a specific radial direction is referred to as the "X-axis," a direction along the X-axis is referred to as the "X1 direction," and a direction opposite the X1 direction is referred to as the "X2 direction." The X-axis is an example of a "first axis." An axis perpendicular to both the central axis AX and the X-axis is referred to as the "Y-axis," a direction along the Y-axis is referred to as the "Y1 direction," and a direction opposite the Y1 direction is referred to as the "Y2 direction." The Y-axis is an example of a "second axis."

[0013] The hub 10 is a structure that is fixed to the shaft 200. In the example shown in FIGS.

[0014] The boss portion 11 is a part of the hub 10 and is a cylindrical portion fixed to the shaft 200. A key groove 14 extending along the central axis AX of the shaft 200 is provided on the inner peripheral surface of the boss portion 11, i.e., the inner peripheral surface of the hub 10. The key groove 14 is a groove that fits with a key (not shown) that protrudes from the outer peripheral surface of the shaft 200. The rim portion 13 is a part of the hub 10 and is an annular portion that surrounds the boss portion 11. In the example shown in FIGS. 2 and 3, a recess 15 extending in the circumferential direction is provided on the outer peripheral surface of the rim portion 13. The connecting portion 12 is a part of the hub 10 and is a disk-shaped portion that connects the boss portion 11 and the rim portion 13. In the example shown in FIG. 1, the connecting portion 12 is provided with four holes 16 and two holes 17 that penetrate the connecting portion 12 in the axial direction. The four holes 16 are arranged at equal intervals in the circumferential direction. The two holes 17 are arranged at equal intervals in the circumferential direction and aligned in the direction along the Y axis.

[0015] The position, shape, and number of recesses 15 are not limited to those shown in Figures 2 and 3, and are arbitrary. Recesses 15 may be provided or omitted as necessary. Furthermore, protrusions extending in the circumferential direction may be provided on the outer peripheral surface of rim portion 13 in addition to or instead of recesses 15. Furthermore, the position, shape, and number of holes 16, 17 are not limited to those shown in Figure 1, and are arbitrary. Furthermore, holes 16, 17 may be provided or omitted as necessary.

[0016] The vibration ring 20 is an annular mass body that fits around the outer periphery of the hub 10 and is arranged concentrically with the hub 10. The inner circumferential surface of the vibration ring 20 faces the outer circumferential surface of the hub 10, specifically the outer circumferential surface of the rim portion 13, with an annular gap between them. The inner circumferential surface of the vibration ring 20 is provided with protrusions 21 that correspond to the recesses 15 described above. Meanwhile, the outer circumferential surface of the vibration ring 20 is provided with a plurality of pulley grooves 22. The plurality of pulley grooves 22 are V-shaped grooves for passing an endless belt that transmits the rotational torque of the shaft 200 to an external mechanism.

[0017] The position, shape, and number of the protrusions 21 are not limited to the examples shown in Figures 2 and 3, and are arbitrary. The protrusions 21 may be provided or omitted as necessary. Furthermore, in addition to or instead of the protrusions 21, recesses extending in the circumferential direction may be provided on the inner peripheral surface of the vibration ring. Furthermore, the plurality of pulley grooves 22 may be provided or omitted as necessary.

[0018] Each of the two rubber dampers 30 is an elastic body that fits between the hub 10 and the vibration ring 20. Therefore, the inner circumferential surface of each rubber damper 30 is in close contact with the outer circumferential surface of the hub 10, and the outer circumferential surface of each rubber damper 30 is in close contact with the inner circumferential surface of the vibration ring 20. Each rubber damper 30 is made of an elastic material and is interposed between the hub 10 and the vibration ring 20. As described above, the outer circumferential surface of the hub 10 is provided with a recess 15, and the inner circumferential surface of the vibration ring 20 is provided with a protrusion 21, and the recess 15 and the protrusion 21 form a structure that prevents the rubber dampers 30 from falling off. In this way, each rubber damper 30 elastically connects the hub 10 and the vibration ring 20.

[0019] The elastic material constituting each damper rubber 30 is not particularly limited, but examples thereof include rubber materials such as AEM (ethylene acrylic rubber), FKM (fluororubber), and EPDM (ethylene propylene diene rubber).The method for forming each damper rubber 30 is not particularly limited, and known rubber molding methods can be used.

[0020] When molding each rubber damper 30, it is preferable to bond each rubber damper 30 to one or both of the hub 10 and the vibration ring 20 by vulcanization adhesion in a mold at the same time as rubber vulcanization. This makes it possible to easily position each rubber damper 30 at a desired position in the circumferential direction between the hub 10 and the vibration ring 20. Furthermore, because each rubber damper 30 is bonded to one or both of the hub 10 and the vibration ring 20, it is possible to prevent each rubber damper 30 from shifting position or falling off. Note that if each rubber damper 30 is not bonded to one or both of the hub 10 and the vibration ring 20, it is positioned between the hub 10 and the vibration ring 20 by press-fitting, for example.

[0021] The two damper rubbers 30 are arranged at a distance from each other in the circumferential direction. The two damper rubbers 30 are also aligned in a direction along the X-axis, and of the two damper rubbers 30, the damper rubber 30 located in the X1 direction with respect to the central axis AX constitutes the elastic portion 31-1, and the damper rubber 30 located in the X2 direction constitutes the elastic portion 31-2. Hereinafter, the elastic portions 31-1 and 31-2 may be referred to as the elastic portions 31 without distinction.

[0022] In this way, the multiple elastic portions 31 are composed of multiple damper rubbers 30 that are spaced apart from one another in the circumferential direction. Therefore, the torsional damper 100 has multiple elastic portions 31 that are fitted between the hub 10 and the vibration ring 20. Here, the multiple elastic portions 31 are spaced apart from one another in the circumferential direction. As a result, gaps G-1 and G-2 are formed between the hub 10 and the vibration ring 20 due to these spaces. The gaps G-1 and G-2 are aligned in the direction along the Y axis. The gap G-1 is located in the Y1 direction relative to the central axis AX. In contrast, the gap G-2 is located in the Y2 direction relative to the central axis AX. Hereinafter, the gaps G-1 and G-2 may be referred to as gap G without distinction.

[0023] In this way, the multiple elastic portions 31 and the multiple gaps G are alternately arranged in the circumferential direction between the hub 10 and the vibration ring 20. This allows the natural frequency in the radial direction of the vibration system formed by the vibration ring 20 and the multiple elastic portions 31 to vary depending on the radial direction. Therefore, even if the natural frequency around the central axis AX of the vibration system is a value suitable for reducing torsional vibration of the shaft 200, the natural frequency in a specific radial direction of the vibration system can be set to a value suitable for reducing bending vibration of the shaft 200. This makes it possible to reduce both torsional vibration and bending vibration of the shaft 200 with a simple configuration.

[0024] As shown in FIG. 2, in a cross section taken along the X-axis and the central axis AX, the elastic portions 31-1 and 31-2 are interposed between the hub 10 and the vibration ring 20 and are in close contact with both the hub 10 and the vibration ring 20. In contrast, as shown in FIG. 3, in a cross section taken along the Y-axis and the central axis AX, the elastic portions 31-1 and 31-2 are not interposed between the hub 10 and the vibration ring 20, but gaps G-1 and G-2 are interposed. Therefore, in a vibration system formed by the vibration ring 20 and the elastic portions 31-1 and 31-2, the natural frequency in the direction along the X-axis is different from the natural frequency in the direction along the Y-axis. Specifically, in this vibration system, the natural frequency in the direction along the X-axis is higher than the natural frequency in the direction along the Y-axis. In other words, in this vibration system, the natural frequency in the direction along the Y-axis is lower than the natural frequency in the direction along the X-axis. The direction along the X axis is the direction in which the radial natural frequency is maximum.The direction along the X axis is the direction in which the radial natural frequency is minimum.

[0025] The natural frequency of the vibration system in the direction along the Y-axis is preferably 0.01 to 0.9 relative to the natural frequency of the vibration system in the direction along the X-axis. This makes it possible to make the natural frequency of the vibration system about the central axis AX a value suitable for reducing torsional vibration of the shaft 200, and the natural frequency of the vibration system in a specific radial direction a value suitable for reducing bending vibration of the shaft 200.

[0026] Furthermore, the specific value of the natural frequency of the vibration system in the direction along the Y axis is not particularly limited, but is preferably 1 kHz or less, more preferably 1 Hz to 500 Hz, and even more preferably 10 Hz to 300 Hz. This makes it possible to suitably reduce vibrations in the radial direction of shaft 200 when shaft 200 is a crankshaft.

[0027] In this embodiment, as described above, the multiple elastic portions 31 are composed of multiple damper rubbers 30, so that it is possible to set a specific radial natural frequency of the vibration system composed of the vibrating ring 20 and the multiple elastic portions 31 depending on the length and arrangement of each damper rubber 30. In the example shown in Fig. 1, each end face in the circumferential direction of each damper rubber 30 is a plane perpendicular to the circumferential direction. Note that each end face in the circumferential direction of each damper rubber 30 is not limited to the example shown in Fig. 1, and may be, for example, a surface that is inclined with respect to the plane perpendicular to the circumferential direction, or a curved surface.

[0028] The two elastic portions 31, i.e., elastic portion 31-1 and elastic portion 31-2, are arranged symmetrically with respect to each other about the X axis. The two gaps G, i.e., gaps G-1 and G-2, are arranged symmetrically with respect to each other about the Y axis.

[0029] In this way, the multiple elastic portions 31 and the multiple gap portions G are arranged line-symmetrically with respect to the X-axis when viewed in the direction along the central axis AX of the shaft 200. This makes it possible to make the natural frequency in the radial direction along the X-axis and the natural frequency in the radial direction along the Y-axis perpendicular to the X-axis different from each other in the vibration system formed by the vibration ring 20 and the multiple elastic portions 31.

[0030] Furthermore, the multiple elastic portions 31 and the multiple voids G are arranged line-symmetrically with respect to the Y axis, which is perpendicular to the X axis, when viewed in the direction along the central axis AX. That is, the multiple elastic portions 31 and the multiple voids G are arranged line-symmetrically with respect to both the X axis and the Y axis when viewed in the direction along the central axis AX. This makes it possible to prevent vibrations that accompany rotation of the torsional damper 100.

[0031] As shown in FIG. 1, each elastic portion 31 and each void portion G has an arc shape along the circumferential direction. In the example shown in FIG. 1, each elastic portion 31 is an arc-shaped space with a central angle β of 90°. Therefore, the circumferential lengths of the multiple elastic portions 31 are equal to each other. Furthermore, the thicknesses and widths of the multiple elastic portions 31 are equal to each other. Similarly, each void portion G is an arc-shaped space with a central angle α of 90°. Therefore, the circumferential lengths of the multiple void portions G are equal to each other. Furthermore, the thicknesses and widths of the multiple void portions G are equal to each other.

[0032] In this way, since the circumferential lengths of the multiple elastic portions 31 are equal to each other, it is easy to arrange the multiple elastic portions 31 and the multiple void portions G in an axisymmetrical arrangement when viewed in the direction along the central axis AX of the shaft 200.

[0033] Note that the central angles α and β are not limited to 90°, and may be smaller or larger than 90°. However, the central angle α of each of the plurality of voids G is preferably 10° or larger and 110° or smaller, more preferably 30° or larger and 110° or smaller, and even more preferably 60° or larger and 100° or smaller. This makes it easy to set the natural frequency in a specific radial direction of the vibration system formed by the vibration ring 20 and the plurality of elastic portions 31 to a value suitable for reducing bending vibration of the shaft 200.

[0034] The circumferential positions of the multiple elastic portions 31 and the multiple voids G are determined based on the key groove 14. This allows the relationship between the rotation angle of the shaft 200 and the circumferential positions of the multiple elastic portions 31 and the multiple voids G to be appropriately set. In the example shown in FIG. 1, the key groove 14 is disposed at a position inclined 45° in the circumferential direction with respect to the X-axis or Y-axis. Note that the circumferential position of the key groove 14 is not limited to the example shown in FIG. 1 and may be on the Y-axis, for example.

[0035] The relationship between the circumferential orientation of torsional damper 100 relative to shaft 200 and the direction of bending vibration of shaft 200 to be reduced is set using keyway 14 as a reference. For example, if shaft 200 is a crankshaft provided in an inline four-cylinder engine, shaft 200 has a serpentine shape on the same plane, and therefore shaft 200 is likely to generate bending vibration in a direction along that plane. Therefore, in this case, the circumferential orientation of torsional damper 100 relative to shaft 200 is set so that the Y axis is on that plane. Note that the circumferential orientation of torsional damper 100 relative to shaft 200 is not limited to this example and is determined depending on the direction of bending vibration of shaft 200 to be reduced. Furthermore, shaft 200 is not limited to a crankshaft provided in an inline four-cylinder engine. For example, shaft 200 may be a crankshaft provided in an engine other than a four-cylinder engine, a crankshaft provided in an engine other than an inline V-type engine, or a shaft other than a crankshaft.

[0036] As described above, torsional damper 100 can reduce both torsional vibration and bending vibration of shaft 200 with a simple configuration.

[0037] 2. Second embodiment A second embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above-described embodiment, the reference numerals used in the description of the above-described embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0038] 4 is a cross-sectional view of a torsional damper 100A according to the second embodiment. The torsional damper 100A has the same configuration as the torsional damper 100 of the first embodiment, except that it has one damper rubber 30A instead of the two damper rubbers 30 of the first embodiment.

[0039] The damper rubber 30A is disposed between the hub 10 and the vibration ring 20 and is an annular elastic body that extends over the entire circumferential area. The damper rubber 30A has elastic portions 31-1 and 31-2 and connecting portions 32-1 and 32-2, which are not shown in Fig. 4. Hereinafter, the connecting portions 32-1 and 32-2 may be referred to as connecting portion 32 without distinction.

[0040] The connecting portion 32-1 connects adjacent ends of the elastic portions 31-1 and 31-2 in the Y1 direction relative to the central axis AX, whereas the connecting portion 32-1 connects adjacent ends of the elastic portions 31-1 and 31-2 in the Y2 direction relative to the central axis AX.

[0041] As described above, the multiple elastic portions 31 of this embodiment are formed from multiple portions of the annular damper rubber 30A that is fitted between the hub 10 and the vibration ring 20. Here, the cross-sectional area of ​​the connecting portion 32, which is the portion of the damper rubber 30A other than the multiple elastic portions 31, is smaller than the cross-sectional area of ​​each of the multiple elastic portions 31. This makes it possible to reduce peeling of each elastic portion 31 from the hub 10 or the vibration ring 20 while providing multiple gaps G. It is also possible to reduce the movement of foreign matter such as dust through each gap G.

[0042] In the example shown in FIG. 4 , the axial width of each connecting portion 32 is smaller than the axial width of each elastic portion 31. This allows the cross-sectional area of ​​the connecting portion 32 to be smaller than the cross-sectional area of ​​each of the multiple elastic portions 31. Furthermore, the inner circumferential surface of each connecting portion 32 is in close contact with the outer circumferential surface of the hub 10, and the outer circumferential surface of each connecting portion 32 is in close contact with the inner circumferential surface of the vibration ring 20. This divides each gap G into a space on one side and a space on the other side in the axial direction. This prevents the movement of foreign matter such as dust through each gap G. Furthermore, the natural frequency in the direction along the Y axis of the vibration system formed by the vibration ring 20 and the multiple elastic portions 31 can be adjusted depending on the width of the connecting portion 32.

[0043] Each connecting portion 32 is disposed at the center of the gap G in the axial direction. Here, each connecting portion 32 is sandwiched between the recessed portion 15 and the protruding portion 21, similar to the elastic portion 31. Note that the axial arrangement of each connecting portion 32 is not limited to the example shown in FIG. 4, and for example, the connecting portions 32 may be disposed unevenly on one end side of the gap G in the axial direction.

[0044] According to the second embodiment described above, both the torsional vibration and the bending vibration of the shaft 200 can be reduced with a simple configuration. 3. Variations Specific modifications that can be added to each of the above-mentioned embodiments are exemplified below. Two or more embodiments arbitrarily selected from the following examples may be combined as appropriate within the scope of not mutually contradicting each other.

[0045] 3-1. Variation 1 5 is a cross-sectional view of a torsional damper 100B according to Modification 1. The torsional damper 100B is configured in the same manner as the torsional damper 100 of the first embodiment, except that it has one damper rubber 30B instead of the two damper rubbers 30 of the first embodiment.

[0046] The damper rubber 30B is an annular elastic body that spans the entire circumferential area between the hub 10 and the vibration ring 20. The damper rubber 30B is configured similarly to the damper rubber 30A of the second embodiment, except that it has connecting portions 33-1 and 33-2 instead of the connecting portions 32-1 and 32-2 of the second embodiment. The damper rubber 30B has elastic portions 31-1 and 31-2 and connecting portions 33-1 and 33-2, which are not shown in FIG. 5. Hereinafter, the connecting portions 33-1 and 33-2 may be referred to as connecting portion 33 without distinction.

[0047] The connecting portion 33-1 connects adjacent ends of the elastic portions 31-1 and 31-2 in the Y1 direction relative to the central axis AX, whereas the connecting portion 33-1 connects adjacent ends of the elastic portions 31-1 and 31-2 in the Y2 direction relative to the central axis AX.

[0048] As described above, the multiple elastic portions 31 of this embodiment are formed from multiple portions of the annular damper rubber 30B that is fitted between the hub 10 and the vibration ring 20. Here, the cross-sectional area of ​​the connecting portion 33, which is the portion of the damper rubber 30B other than the multiple elastic portions 31, is smaller than the cross-sectional area of ​​each of the multiple elastic portions 31. This makes it possible to reduce peeling of each elastic portion 31 from the hub 10 or the vibration ring 20 while providing multiple gaps G. It is also possible to reduce the movement of foreign matter such as dust through each gap G.

[0049] 5, the axial thickness of each connecting portion 33 is smaller than the axial thickness of each elastic portion 31. This allows the cross-sectional area of ​​the connecting portion 32 to be smaller than the cross-sectional area of ​​each of the multiple elastic portions 31. Furthermore, the inner circumferential surface of each connecting portion 33 is in close contact with the outer circumferential surface of the hub 10, while the outer circumferential surface of each connecting portion 32 is not in contact with the inner circumferential surface of the vibration ring 20. Therefore, each connecting portion 33 does not substantially affect the natural frequency in the direction along the Y-axis of the vibration system formed by the vibration ring 20 and the multiple elastic portions 31.

[0050] The width of each connecting portion 33 is equal to the width of each elastic portion 31. This increases the contact area between each connecting portion 33 and the hub 10. Note that the width of each connecting portion 33 may be smaller than the width of each elastic portion 31. The inner peripheral surface of each connecting portion 33 may not contact the outer peripheral surface of the hub 10. In this case, the outer peripheral surface of each connecting portion 33 may be in close contact with the inner peripheral surface of the vibration ring 20.

[0051] According to the above-described first modification, both the torsional vibration and the bending vibration of the shaft 200 can be reduced with a simple configuration.

[0052] 3-2. Variation 2 In the above embodiment, the number of each of the elastic portions 31 and the void portions G is exemplified as two, but the present invention is not limited to this embodiment, and the number may be three or more. Furthermore, the central angle of each of the elastic portions 31 and the void portions G is not limited to 90°.

[0053] 6 is a plan view of a torsional damper 100C according to Modification 2. The torsional damper 100C is configured in the same manner as the torsional damper 100 of the first embodiment, except that it includes four damper rubbers 30C instead of the two damper rubbers 30 of the first embodiment.

[0054] The four damper rubbers 30C constitute elastic portions 31-a, 31-b, 31-c, and 31-d. The elastic portions 31-a and 31-b are configured by dividing the elastic portion 31-1 of the first embodiment in half in the circumferential direction, and a gap G-3 is provided between the elastic portions 31-a and 31-b. The elastic portions 31-c and 31-d are configured by dividing the elastic portion 31-2 of the first embodiment in half in the circumferential direction, and a gap G-4 is provided between the elastic portions 31-c and 31-d.

[0055] The circumferential lengths of the gaps G-3 and G-4 are shorter than the circumferential lengths of the gaps G-1 and G-2, respectively, which are as described in the first embodiment.

[0056] According to the above-described second modification, both the torsional vibration and the bending vibration of the shaft 200 can be reduced with a simple configuration.

[0057] 3-3. Variation 3 In the above embodiment, the gap G is open in the axial direction, but the present invention is not limited to this. For example, the gap G may be sealed as a hollow portion of the damper rubber.

[0058] 3-4. Variation 4 In the above-described embodiment, the elastic portions 31 and the voids G are configured to be line-symmetric with respect to both the X-axis and the Y-axis when viewed in the direction along the central axis AX, but the present invention is not limited to this embodiment, and the elastic portions 31 and the voids G do not have to be line-symmetric with respect to one or both of the X-axis and the Y-axis when viewed in the direction along the central axis AX. In this case, a mass adjustment mechanism is employed as necessary to prevent vibrations associated with rotation of the torsional damper 100.

[0059] 4. Notes For example, the following aspects can be understood from the above embodiment and modified examples.

[0060] (Appendix 1) A first aspect, which is a preferred example of the torsional damper of the present disclosure, comprises a hub fixed to a shaft, an annular vibration ring that follows the outer periphery of the hub, and a plurality of elastic parts that are fitted between the hub and the vibration ring, the plurality of elastic parts being arranged at intervals from one another in the circumferential direction, and a plurality of gaps formed by the intervals between the hub and the vibration ring.

[0061] In the above-described embodiment, the plurality of elastic portions and the plurality of voids are alternately arranged in the circumferential direction between the hub and the vibration ring, so that the natural frequency in the radial direction of the vibration system formed by the vibration ring and the plurality of elastic portions can be varied depending on the radial direction. Therefore, even if the natural frequency around the central axis of the vibration system is set to a value suitable for reducing the torsional vibration of the shaft, the natural frequency in a specific radial direction of the vibration system can be set to a value suitable for reducing the bending vibration of the shaft. This makes it possible to reduce both the torsional vibration and the bending vibration of the shaft with a simple configuration.

[0062] (Note 2) In the second aspect, which is a preferred example of the first aspect, the elastic portions have the same circumferential length. In this aspect, it is easy to arrange the elastic portions and the void portions in line symmetry when viewed in the direction along the central axis of the shaft.

[0063] (Supplementary Note 3) In a third aspect, which is a preferred example of the first or second aspect, each of the plurality of voids is an arc-shaped space with a central angle of 10° or more and 110° or less. In the above aspect, it is easy to set the natural frequency in a specific radial direction of the vibration system composed of the vibration ring and the plurality of elastic parts to a value suitable for reducing bending vibration of the shaft.

[0064] (Note 4) In a fourth aspect, which is a preferred example of any of the first to third aspects, the elastic portions are made up of a plurality of rubber dampers arranged at intervals. In the above aspects, the circumferential length of each gap can be set according to the length and arrangement of each rubber damper.

[0065] (Appendix 5) In a fifth aspect, which is a preferred example of any of the first to third aspects, the elastic portions are formed of a plurality of portions of an annular damper rubber fitted between the hub and the vibration ring, and the cross-sectional area of ​​the damper rubber other than the elastic portions is smaller than the cross-sectional area of ​​each of the elastic portions. In this aspect, while providing a plurality of gaps, it is possible to reduce peeling of each elastic portion from the hub or the vibration ring. It is also possible to reduce the movement of foreign matter such as dust through each gap.

[0066] (Supplementary Note 6) In a sixth aspect which is a preferred example of any of the first to fifth aspects, the elastic portions and the void portions are arranged symmetrically with respect to a first axis when viewed in a direction along the central axis of the shaft. In the above aspect, in a vibration system constituted by a vibration ring and elastic portions, the natural frequency in the radial direction along the first axis and the natural frequency in the radial direction along a second axis perpendicular to the first axis can be made different from each other.

[0067] (Supplementary Note 7) In a seventh aspect, which is a preferred example of the sixth aspect, the elastic portions and the void portions are arranged symmetrically with respect to a second axis perpendicular to the first axis when viewed in the direction along the central axis. In the above aspect, vibrations caused by rotation of the torsional damper can be prevented.

[0068] (Appendix 8) In an eighth aspect, which is a preferred example of any of the first to seventh aspects, a key groove extending along the central axis of the shaft is provided on the inner peripheral surface of the hub, and the positions of the elastic portions and the voids in the circumferential direction are determined based on the key groove. In this aspect, the relationship between the rotation angle of the shaft and the positions of the elastic portions and the voids in the circumferential direction can be appropriately set. [Explanation of symbols]

[0069] 10...hub, 11...boss portion, 12...connecting portion, 13...rim portion, 14...key groove, 15...recess, 16...hole, 17...hole, 20...vibration ring, 21...projection portion, 22...pulley groove, 30...damper rubber, 30A...damper rubber, 30B...damper rubber, 30C...damper rubber, 31-1...elastic portion, 31-2...elastic portion, 31-a...elastic portion, 31-b...elastic portion, 31-c...elastic portion , 31-d...elastic portion, 32-1...connecting portion, 33-1...connecting portion, 33-2...connecting portion, 100...torsional damper, 100A...torsional damper, 100B...torsional damper, 100C...torsional damper, 200...shaft, AX...central axis, G-1...gap portion, G-2...gap portion, G-3...gap portion, G-4...gap portion, α...central angle, β...central angle.

Claims

1. a hub fixed to the shaft; an annular vibration ring along the outer periphery of the hub; a plurality of elastic portions fitted between the hub and the vibration ring; The elastic portions are arranged at intervals in the circumferential direction, A plurality of gaps are provided between the hub and the vibration ring due to the spacing. Torsional damper.

2. The elastic portions have the same circumferential length.

2. The torsional damper of claim 1.

3. Each of the plurality of voids is an arc-shaped space having a central angle of 10° or more and 110° or less.

2. The torsional damper of claim 1.

4. The plurality of elastic portions are constituted by a plurality of damper rubbers arranged at intervals.

2. The torsional damper of claim 1.

5. the plurality of elastic portions are formed by a plurality of portions of annular damper rubber fitted between the hub and the vibration ring, a cross-sectional area of ​​the damper rubber other than the plurality of elastic portions is smaller than a cross-sectional area of ​​each of the plurality of elastic portions; 2. The torsional damper of claim 1.

6. the plurality of elastic portions and the plurality of void portions are arranged line-symmetrically with respect to a first axis when viewed in a direction along the central axis of the shaft; 2. The torsional damper of claim 1.

7. the plurality of elastic portions and the plurality of void portions are arranged line-symmetrically with respect to a second axis perpendicular to the first axis when viewed in a direction along the central axis; 7. The torsional damper according to claim 6.

8. The inner peripheral surface of the hub is provided with a key groove extending along the central axis of the shaft, The positions of the elastic portions and the gap portions in the circumferential direction are determined based on the key groove. A torsional damper according to any one of claims 1 to 7.

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