Gear structure

Abstract

To effectively reduce gear noise.SOLUTION: A gear structure 100 includes a gear member 20 including an outer peripheral surface 31 on which a plurality of gear teeth 21 is provided and an inner peripheral surface 32 inside the outer peripheral surface 31, an annular mass body 60 provided inside the inner peripheral surface 32, and an elastic body 70 interposed between the gear member 20 and the mass body 60.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a gear structure. [Background technology]

[0002] For example, in a drive mechanism mounted on a moving body such as an automobile, gear noises such as tooth-crash noises caused by collision of gear teeth between multiple gears or meshing noises caused by deformation of each tooth are problems. Patent Document 1 discloses a configuration in which annular grooves are formed on both sides of a gear in the axial direction, and annular elastic bodies that absorb vibrations are housed in each annular groove. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-134230 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the configuration of Patent Document 1 has a problem that the rigidity of the gear is reduced by forming the annular groove on the surface, which results in a decrease in reliability regarding torque transmission. Also, the vibration damping effect is limited by the elastic body accommodated in the annular groove alone. In consideration of the above circumstances, one aspect of the present disclosure aims to effectively reduce gear noise. [Means for solving the problem]

[0005] In order to solve the above problems, a gear structure according to one embodiment of the present disclosure comprises a gear member including an outer peripheral surface on which a plurality of gear teeth are provided and an inner peripheral surface inside the outer peripheral surface, an annular mass body provided inside the inner peripheral surface, and an elastic body interposed between the gear member and the mass body. [Brief description of the drawings]

[0006] [Figure 1]FIG. 2 is a plan view of a gear mechanism according to the embodiment. [Diagram 2] 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] This shows the frequency characteristics of the operating sound generated by the operation of the gear mechanism. [Figure 4] This shows the frequency characteristics of the operating sound generated by the operation of the gear mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The embodiments for carrying out the present disclosure will be described with reference to the drawings. Note that in each drawing, the dimensions and scale of each element may differ from those of the actual product. The embodiment described below is an exemplary embodiment assumed when carrying out the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0008] Fig. 1 is a plan view of a gear mechanism 100 according to one embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. The gear mechanism 100 is used in a drive mechanism (e.g., a transmission or a differential) that transmits power from a power source such as an internal combustion engine or an electric motor to wheels in a moving body such as an automobile.

[0009] 1 and 2, the gear mechanism 100 includes a shaft member 11 and a gear structure 12. The shaft member 11 is a cylindrical shaft that is rotatable about a rotation axis C. The gear structure 12 is a rotating body fixed to the shaft member 11. The shaft member 11 may be understood as an element of the gear structure 12.

[0010] In the following description, the direction along the circumference of a virtual circle of any diameter centered on the rotation axis C is referred to as the "circumferential direction," and the direction of the radius of the virtual circle is referred to as the "radial direction." Additionally, the radial direction toward the rotation axis C is referred to as the "inner side," and the direction away from the rotation axis C is referred to as the "outer side."

[0011] 1 and 2, the gear structure 12 includes a gear member 20, a mass body 60, and an elastic body 70. In addition, in Fig. 1, the mass body 60 and the elastic body 70 are shaded for convenience.

[0012] The gear member 20 is a disk-shaped spur gear. Specifically, the gear member 20 includes a first portion 30, a second portion 40, and a connecting portion 50. The first portion 30, the second portion 40, and the connecting portion 50 are integrally formed from a material having high mechanical strength, such as carbon steel for machine construction (S45C), chromium-molybdenum alloy steel (SCM440, SCM415), stainless steel (SUS303), or the like.

[0013] The first portion 30 is an annular portion including an outer peripheral surface 31 and an inner peripheral surface 32, and is disposed concentrically with the rotation axis C. The outer peripheral surface 31 is a wall surface of the first portion 30 facing outward, and the inner peripheral surface 32 is a wall surface on the inside of the outer peripheral surface 31. As illustrated in FIG. 1 , a plurality of gear teeth 21 are disposed at equal intervals in the circumferential direction on the outer peripheral surface 31 of the first portion 30. As can be understood from the above description, the gear member 20 is a structure including the outer peripheral surface 31 on which the plurality of gear teeth 21 are disposed, and the inner peripheral surface 32 on the inside of the outer peripheral surface 31.

[0014] 1 and 2, the second portion 40 is an annular portion including an outer peripheral surface 41 and an inner peripheral surface 42, and is disposed concentrically with the rotation axis C. The outer peripheral surface 41 is a wall surface of the second portion 40 facing outward, and the inner peripheral surface 42 is a wall surface on the inside of the outer peripheral surface 41. The outer diameter of the second portion 40 is smaller than the inner diameter of the first portion 30. The second portion 40 is located inside the first portion 30. That is, the inner peripheral surface 32 of the first portion 30 and the outer peripheral surface 41 of the second portion 40 face each other with a predetermined gap therebetween.

[0015] The connecting portion 50 is an annular portion disposed between the first portion 30 and the second portion 40 to connect the first portion 30 and the second portion 40. The thickness of the connecting portion 50 is less than the thickness of the first portion 30 (the dimension in the direction of the rotation axis C) and the thickness of the second portion 40. Therefore, as illustrated in FIG. 2, an annular space S is formed that is surrounded by the inner peripheral surface 32 of the first portion 30, the outer peripheral surface 41 of the second portion 40, and the surface 51 of the connecting portion 50.

[0016] The mass body 60 and the elastic body 70 are accommodated in the space S. That is, the mass body 60 and the elastic body 70 are disposed between the first portion 30 and the second portion 40. As illustrated in FIG. 2, the mass body 60 and the elastic body 70 are located within a range between the top surface 35 of the first portion 30 and the surface 51 of the connecting portion 50 in the direction of the rotation axis C. Specifically, the mass body 60 and the elastic body 70 face the surface 51 of the connecting portion 50 with a gap therebetween. According to the above configuration, the possibility of contact between the mass body 60 and the gear member 20 is reduced. Therefore, noise (hitting sound) caused by contact between the mass body 60 and the gear member 20 can be suppressed. The elastic body 70 may contact the connecting portion 50.

[0017] The mass body 60 is a damper mass installed inside the inner circumferential surface 32 of the gear member 20. Specifically, the mass body 60 is a structure formed from a highly rigid metal material such as iron or stainless steel, and is formed in an annular shape including an outer circumferential surface 61 and an inner circumferential surface 62.

[0018] Specifically, the mass body 60 is a structure in which a main body portion 66 and a protrusion portion 67 are integrally formed. The main body portion 66 is an annular portion having a rectangular cross section. The bottom surface of the main body portion 66 contacts the surface 51 of the connecting portion 50. The protrusion portion 67 is an annular portion protruding from the vicinity of the outer periphery of the main body portion 66 in the direction of the rotation axis C. The outer periphery surface 61 is a wall surface that spans the main body portion 66 and the protrusion portion 67, and the inner periphery surface 62 is a wall surface of the main body portion 66 that faces inward. According to a configuration in which the protrusion portion 67 is provided on the mass body 60, it is easier to ensure the area of ​​the outer periphery surface 61 compared to a configuration in which the mass body 60 is composed of only the main body portion 66.

[0019] The outer diameter of the mass body 60 is smaller than the inner diameter of the first portion 30. The outer peripheral surface 61 of the mass body 60 faces the inner peripheral surface 32 of the first portion 30 with a gap therebetween. In other words, the mass body 60 is surrounded by the first portion 30 over its entire circumference. The inner diameter of the mass body 60 is larger than the outer diameter of the second portion 40. The inner peripheral surface 62 of the mass body 60 faces the outer peripheral surface 41 of the second portion 40 with a gap therebetween. As described above, the mass body 60 is disposed between the first portion 30 and the second portion 40 of the gear member 20.

[0020] The elastic body 70 is a damper spring formed from various elastic materials such as rubber or resin. Specifically, the elastic body 70 is an annular structure including an outer circumferential surface 71 and an inner circumferential surface 72, and is disposed concentrically with the rotation axis C. The outer circumferential surface 71 is a wall surface of the elastic body 70 facing outward, and the inner circumferential surface 72 is a wall surface on the inside of the outer circumferential surface 71.

[0021] The elastic body 70 is disposed between the gear member 20 and the mass body 60. Specifically, the elastic body 70 is disposed between the first portion 30 of the gear member 20 and the mass body 60. That is, the elastic body 70 is interposed between the inner peripheral surface 32 of the gear member 20 and the outer peripheral surface 61 of the mass body 60. More specifically, the outer peripheral surface 71 of the elastic body 70 is in close contact with the inner peripheral surface 32 of the gear member 20, and the inner peripheral surface 72 of the elastic body 70 is in close contact with the outer peripheral surface 61 of the mass body 60. As described above, the gear member 20 and the mass body 60 are elastically connected via the elastic body 70. Specifically, the mass body 60 is elastically connected to the first portion 30 of the gear member 20 via the elastic body 70.

[0022] In the above configuration, the mass body 60 and the elastic body 70 form a dynamic vibration absorber D (dynamic damper). The dynamic vibration absorber D is installed between the first portion 30 and the second portion 40 of the gear member 20. Specifically, the dynamic vibration absorber D is connected to the inner peripheral surface 32 of the first portion 30. The dynamic vibration absorber D absorbs vibrations (particularly natural vibration components in the radial direction) of the shaft member 11 and the gear structure 12. That is, the displacement of the shaft member 11 and the gear structure 12 in the radial direction is suppressed. Therefore, gear noise during rotation of the gear structure 12 can be effectively reduced.

[0023] For example, when the shaft member 11 vibrates in the radial direction, teeth striking noise due to collision between each gear tooth 21 of the gear member 20 and each gear tooth of a mating gear (not shown) meshing with the gear structure 12 becomes apparent. Furthermore, when the shaft member 11 vibrates in the radial direction while the gear structure 12 is meshed with the mating gear, a load acts on each gear tooth 21 of the gear member 20, causing deformation, and meshing noise due to deformation of each gear tooth 21 becomes apparent. According to this embodiment, the dynamic vibration absorber D composed of the mass body 60 and the elastic body 70 absorbs the radial natural vibration of the shaft member 11 and the gear structure 12. Therefore, gear noise such as teeth striking noise or meshing noise can be effectively reduced.

[0024] Figures 3 and 4 show frequency characteristics of operating sounds generated by the operation of the gear mechanism 100. Figures 3 and 4 show frequency characteristics of operating sounds for the gear mechanism 100 of this embodiment in which the dynamic vibration absorber D is installed, and for a configuration in which the dynamic vibration absorber D is not installed (hereinafter referred to as "comparative example").

[0025] 3 shows frequency characteristics of operating noise focusing on radial vibration in the gear mechanism 100. As can be seen from FIG. 3, the peaks of operating noise caused by each radial vibration mode are reduced by installing the dynamic vibration absorber D of this embodiment compared to the comparative example. That is, according to this embodiment, as described above, gear noise such as tooth rattle noise or meshing noise caused by radial vibration can be effectively reduced. As described above, the dynamic vibration absorber D of this embodiment is configured to reduce radial vibration in the gear mechanism 100.

[0026] FIG. 4 shows frequency characteristics of operation noise focusing on a plurality of different vibration modes. As illustrated in FIG. 4, in the comparative example, local peaks due to each vibration mode of the gear member 20 are observed in the operation noise. The peak P1 in FIG. 4 is a component due to a vibration mode (curvature mode) in which the gear member 20 is curved such that the central portion and the peripheral portion of the gear member 20 are different in position in the direction of the rotation axis C. The peak P2 in FIG. 4 is a component due to a vibration mode (expansion mode) in which the gear member 20 expands and contracts in the radial direction in a plane perpendicular to the rotation axis C. As can be understood from FIG. 4, the peak P1 due to the curvature mode and the peak P2 due to the expansion mode are reduced compared to the comparative example by installing the dynamic vibration absorber D in this embodiment. That is, according to this embodiment, the gear noise due to the curvature mode and the expansion mode can also be effectively reduced. As described above, the dynamic vibration absorber D in this embodiment is configured to reduce the vibration of the curvature mode and the expansion mode in the gear member 20.

[0027] In particular, in this embodiment, the mass body 60 is elastically connected to the inner circumferential surface 32 of the gear member 20 on the inside of the outer circumferential surface 31 on which the multiple gear teeth 21 are provided, via the elastic body 70. Specifically, the mass body 60 is elastically connected to the inner circumferential surface 32 of the first portion 30 via the elastic body 70. Therefore, compared to a form in which the mass body 60 is elastically connected to the second portion 40 or the connecting portion 50, for example, the effect of reducing gear noise is significant.

[0028] B: Variation Specific modified embodiments that can be added to the above-mentioned embodiments are illustrated below. Two or more embodiments selected from the following examples may be appropriately combined as long as they are not mutually contradictory.

[0029] (1) The shape of the mass body 60 is arbitrary and is not limited to the above-mentioned examples. For example, the protrusion 67 of the mass body 60 may be omitted. The mass body 60 may be configured by combining multiple parts formed of different materials.

[0030] (2) The form of the elastic body 70 is arbitrary and is not limited to the above-mentioned examples. For example, the elastic body 70 may be configured by laminating multiple layers formed of different materials. Furthermore, the elastic body 70 may be configured by multiple parts configured as separate bodies. For example, the elastic body 70 may be configured by multiple parts installed at intervals in the circumferential direction in the annular space between the inner circumferential surface 32 of the first portion 30 and the outer circumferential surface 61 of the mass body 60.

[0031] (3) In the above embodiment, the elastic body 70 is provided between the mass body 60 and the first portion 30, but the position at which the elastic body 70 is provided is not limited to the above embodiment. For example, a configuration in which the elastic body 70 is provided between the mass body 60 and the second portion 40, or a configuration in which the elastic body 70 is provided between the mass body 60 and the connecting portion 50 is also possible. The elastic body 70 may be provided between the mass body 60 and two or more portions selected from the first portion 30, the second portion 40, and the connecting portion 50.

[0032] (4) In the above embodiment, a spur gear is exemplified as the gear structure 12, but the present disclosure is applicable to any type of gear, such as a bevel gear or a helical gear. In addition, the gear mechanism 100 may be used for any purpose, and is not limited to a drive mechanism for a moving body such as an automobile.

[0033] C: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0034] A gear structure according to one aspect (aspect 1) of the present disclosure includes a gear member including an outer circumferential surface on which a plurality of gear teeth are provided and an inner circumferential surface inside the outer circumferential surface, an annular mass body provided inside the inner circumferential surface, and an elastic body interposed between the gear member and the mass body. In the above aspect, the mass body and the elastic body form a dynamic vibration absorber. The dynamic vibration absorber absorbs vibrations of the gear structure (particularly natural vibration components in the radial direction). In other words, the displacement of the gear structure in the radial direction is suppressed. Therefore, gear noise during rotation of the gear structure can be effectively reduced.

[0035] In a specific example (Aspect 2) of Aspect 1, the elastic body is interposed between the inner peripheral surface of the gear member and the outer peripheral surface of the mass body. In the above aspect, the mass body is elastically connected via the elastic body to the inner peripheral surface inside the outer peripheral surface on which the multiple gear teeth are provided. Therefore, the effect of reducing gear noise is remarkable compared to, for example, a configuration in which the mass body is connected to a portion other than the inner peripheral surface of the gear member.

[0036] In a specific example (aspect 3) of aspect 1, the gear member includes an annular first portion including the outer peripheral surface and the inner peripheral surface, an annular second portion located inside the first portion, and an annular connecting portion disposed between the first portion and the second portion to connect the first portion and the second portion, the mass body is disposed between the first portion and the second portion, and the elastic body is disposed between the first portion and the mass body. In the above aspect, the mass body is elastically connected to the inner peripheral surface of the first portion of the gear member on which a plurality of gear teeth are disposed, via the elastic body. Therefore, the effect of reducing gear noise is remarkable, for example, compared to a form in which the mass body is elastically connected to the second portion. [Explanation of symbols]

[0037] 100...gear mechanism, 11...shaft member, 12...gear structure, 20...gear member, 21...gear teeth, 30...first part, 31...outer surface, 32...inner surface, 40...second part, 41...outer surface, 42...inner surface, 50...connecting part, 51...surface, 60...mass body, 61...outer surface, 62...inner surface, 66...main body, 67...protrusion, 70...elastic body, 71...outer surface, 72...inner surface, D...dynamic vibration absorber.

Claims

1. a gear member including an outer circumferential surface on which a plurality of gear teeth are provided and an inner circumferential surface inside the outer circumferential surface; an annular mass body disposed inside the inner circumferential surface; an elastic body interposed between the gear member and the mass body; A gear structure comprising:

2. The elastic body is interposed between the inner peripheral surface of the gear member and the outer peripheral surface of the mass body. The gear structure of claim 1.

3. The gear member is an annular first portion including the outer circumferential surface and the inner circumferential surface; an annular second portion located inside the first portion; a ring-shaped connecting portion disposed between the first portion and the second portion to connect the first portion and the second portion, the mass is disposed between the first portion and the second portion; The elastic body is disposed between the first portion and the mass. The gear structure of claim 1.

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