Helical gear

Abstract

To provide a helical gear which can suppress noise.SOLUTION: A helical gear 10 comprises an outer ring 100 having a plurality of teeth 110 on an external periphery, an inner ring 200 arranged on the inside of the outer ring 100 coaxially therewith, and an annular elastic shock absorber 300 arranged between the outer ring 100 and the inner ring 200. A whirl stop structure for limiting relative rotation of the outer ring 100 and the inner ring 200 within a certain range is arranged between an internal peripheral face of the outer ring 100 and an external peripheral face of the inner ring 200. Also, a tilt suppression structure for suppressing tilting of the outer ring 100 with respect to the inner ring 200 while permitting the relative rotation of the outer ring 100 and the inner ring 200 is arranged.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] For example, in the case of gears installed in the drive units of automobiles, a technique for providing a buffer elastic body to suppress noise is known. That is, a technique is known in which the gear includes an outer ring, an inner ring, and an annular elastic body provided between the outer ring and the inner ring. However, in the case of helical gears, a force acts in a torsional direction on the outer ring, causing the outer ring to tilt relative to the inner ring through the elastic body, generating abnormal noise, making it difficult to suppress noise with conventional structures. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 4-362346 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a helical gear capable of suppressing noise. [Means for solving the problem]

[0005] The present invention employs the following means to solve the above problems.

[0006] That is, the helical gear of the present invention has the following features: an outer ring having a plurality of teeth on an outer periphery; an inner ring disposed concentrically inside the outer ring; an annular elastic buffer disposed between the outer ring and the inner ring; Equipped with picture, A rotation prevention structure is provided between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to limit relative rotation between the outer ring and the inner ring within a certain range, The outer ring and the inner ring have a tilt suppression structure that suppresses tilt of the outer ring relative to the inner ring while allowing relative rotation between the outer ring and the inner ring within a certain range. A helical gear, a buffer unit having the elastic buffer body; The buffer unit is fixed to the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, respectively, and is arranged to slide on either a wall surface of the outer ring that is perpendicular to the central axis or a wall surface of the inner ring that is perpendicular to the central axis, thereby forming the tilt suppression structure. It is characterized by:

[0007] According to the present invention, the provision of a rotation prevention structure allows for direct transmission of rotational motion between the outer ring and the inner ring when torque above a certain level is applied. Furthermore, the provision of an elastic buffer reduces vibrations through a damping effect, thereby suppressing noise. Furthermore, the provision of a tilt suppression structure also helps to suppress the generation of abnormal noise.

[0012] The buffer unit comprises: a first reinforcing ring having a first cylindrical portion whose outer peripheral surface is fixed to the inner peripheral surface of the outer ring by press fitting and whose inner peripheral surface has the elastic buffer fixed thereto, and an inward flange portion provided at an end of the first cylindrical portion; a second reinforcing ring having an inner circumferential surface fixed to the outer circumferential surface of the inner ring by press fitting and a second cylindrical portion to which the elastic buffer is fixed on the outer circumferential surface; a dry bearing including: a third cylindrical portion whose inner peripheral surface is fixed to the outer peripheral surface of the inner ring by press fitting and which is sandwiched between the inner peripheral surface of a large-diameter cylindrical portion of the second reinforcing ring excluding the second cylindrical portion and the outer peripheral surface of the inner ring; and an outward flange portion which is provided at an end of the third cylindrical portion and is provided so as to slide against both a wall surface which is provided on the outer ring and which is perpendicular to the central axis, and the inward flange portion; It is advisable to prepare the following. [Effects of the Invention]

[0014] As described above, according to the present invention, noise can be suppressed. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view of a helical gear according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a front view showing a state in which the elastic buffer body of the helical gear according to the first embodiment of the present invention has been removed. [Figure 3] FIG. 3 is a schematic cross-sectional view of a helical gear according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a helical gear according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a front view showing a helical gear according to a second embodiment of the present invention with the elastic buffer removed. [Figure 6] FIG. 6 is a schematic cross-sectional view of a helical gear according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The following detailed description of the present invention will be given by way of example with reference to the accompanying drawings, although the dimensions, materials, shapes, relative positions, etc. of the components described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0017] Example 1 A helical gear according to a first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a front view of the helical gear according to the first embodiment of the present invention. Figure 2 is a front view of the helical gear according to the first embodiment of the present invention with an elastic buffer removed. Figure 3 is a schematic cross-sectional view of the helical gear according to the first embodiment of the present invention. Note that Figure 3 is a cross-sectional view taken along line AA in Figure 1. The outer ring and inner ring in Figure 3 correspond to the cross-sectional view taken along line AA in Figure 2. Hereinafter, the central axis of the helical gear will be referred to as the "central axis."

[0018] <Configuration of helical gear> The helical gear 10 according to this embodiment includes an outer ring 100 having a plurality of teeth 110 on its outer periphery, The bearing comprises an inner ring 200 arranged concentrically inside outer ring 100, and an annular elastic buffer 300 arranged between outer ring 100 and inner ring 200. The tooth traces of the multiple teeth 110 are configured to extend obliquely relative to the central axis. Elastic buffer 300 is made of an elastomer material (such as rubber), and is directly fixed to the inner circumferential surface of outer ring 100 and the outer circumferential surface of inner ring 200 by vulcanization bonding or the like.

[0019] A rotation prevention structure is provided between the inner peripheral surface of outer ring 100 and the outer peripheral surface of inner ring 200, limiting the relative rotation between outer ring 100 and inner ring 200 to a certain range. More specifically, a plurality of protrusions 120 are provided at circumferential intervals on the inner peripheral surface of outer ring 100, and a plurality of protrusions 220 are also provided at circumferential intervals on the outer peripheral surface of inner ring 200. In this embodiment, all of the plurality of protrusions 120 have the same dimensions and shape and are provided at equal intervals in the circumferential direction. Similarly, all of the plurality of protrusions 220 have the same dimensions and shape and are provided at equal intervals in the circumferential direction. A protrusion 220 is disposed between adjacent protrusions 120, and a gap is formed between the protrusions 120 and the protrusions 220. With the above configuration, the outer ring 100 and the inner ring 200 are allowed to rotate relative to each other within a certain range, and when an external force causes rotational motion and the protrusions 120 and 220 come into contact, the outer ring 100 and the inner ring 200 rotate together.

[0020] The inner peripheral surface of outer ring 100 is provided with a large diameter portion 130 to which elastic buffer 300 is fixed, and a stepped surface 140 that positions elastic buffer 300. The outer peripheral surface of inner ring 200 is provided with a small diameter portion 230 to which elastic buffer 300 is fixed, and a stepped surface 240 that positions elastic buffer 300. With the above configuration, elastic buffer 300 is positioned with high precision.

[0021] The helical gear 10 according to this embodiment also has a tilt suppression structure that suppresses tilt of the outer ring 100 relative to the inner ring 200 (tilt relative to the central axis) while allowing relative rotation between the outer ring 100 and the inner ring 200 within a certain range. More specifically, the tilt suppression structure is formed by a wall surface 150 provided on the outer ring 100 and perpendicular to the central axis and a wall surface 250 provided on the inner ring 200 and perpendicular to the central axis being arranged to slide against each other. In this embodiment, the inner surface of an inward flange portion provided on the end of the outer ring 100 opposite the side to which the elastic buffer 300 is fixed serves as the wall surface 150. The end face of the end of the inner ring 200 opposite the side to which the elastic buffer 300 is fixed serves as the wall surface 250.

[0022] <Advantages of the helical gear according to this embodiment> The helical gear 10 according to this embodiment can transmit rotational motion between a member (such as a rotating shaft) to which the inner ring 200 is fixed and a member (such as a gear) that meshes with the teeth 110 of the outer ring 100. In the case of low torque, rotational motion is transmitted between the outer ring 100 and the inner ring 200 via the elastic buffer 300. Furthermore, by providing an anti-rotation structure, when torque above a certain level is applied, rotational motion is transmitted directly between the outer ring 100 and the inner ring 200. Furthermore, the provision of the elastic buffer 300 reduces vibrations through a damping effect, thereby suppressing noise.

[0023] Furthermore, the tilt suppression structure suppresses tilt of the outer ring 100 relative to the inner ring 200 (tilt relative to the central axis). That is, in the helical gear 10, an external force (a force in the rotational direction) acts on the multiple teeth 110 of the outer ring 100, causing a force to act on the outer ring 100 that twists the outer ring 100. This causes the outer ring 100 to tilt relative to the inner ring 200, but the tilt suppression structure can suppress tilt of the outer ring 100. This suppresses the generation of abnormal noise, further reducing noise.

[0024] Example 2 A helical gear according to a second embodiment of the present invention will be described with reference to Figures 4 to 6. Figure 4 is a front view of the helical gear according to the second embodiment of the present invention. Figure 5 is a front view of the helical gear according to the second embodiment of the present invention with the elastic buffer removed. Figure 6 is a schematic cross-sectional view of the helical gear according to the second embodiment of the present invention. Note that Figure 6 is a cross-sectional view taken along line B-B in Figure 4. The outer ring and inner ring in Figure 6 correspond to the cross-sectional view taken along line B-B in Figure 5. Hereinafter, the central axis of the helical gear will be referred to as the "central axis".

[0025] <Configuration of helical gear> The helical gear 10A according to this embodiment includes an outer ring 100A having a plurality of teeth 110 on its outer periphery, an inner ring 200A arranged concentrically inside the outer ring 100A, and a buffer unit 400 having an annular elastic buffer 440 arranged between the outer ring 100A and the inner ring 200A. The tooth traces of the plurality of teeth 110 are configured to extend obliquely with respect to the central axis.

[0026] A rotation prevention structure is provided between the inner peripheral surface of outer ring 100A and the outer peripheral surface of inner ring 200A, limiting the relative rotation between outer ring 100A and inner ring 200A to a certain range. More specifically, a plurality of protrusions 120 are provided at intervals in the circumferential direction on the inner peripheral surface of outer ring 100A, and a plurality of protrusions 220 are provided at intervals in the circumferential direction on the outer peripheral surface of inner ring 200A. In this embodiment, all of the plurality of protrusions 120 have the same dimensions and shape and are provided at equal intervals in the circumferential direction. Similarly, all of the plurality of protrusions 220 have the same dimensions and shape and are provided at equal intervals in the circumferential direction. A protrusion 220 is disposed between adjacent protrusions 120, and a gap is formed between the protrusions 120 and the protrusions 220. With the above configuration, outer ring 100A and inner ring 200A are allowed to rotate relative to each other within a certain range, and when an external force causes rotational motion and protrusions 120 and 220 come into contact, outer ring 100A and inner ring 200A rotate together.

[0027] The inner peripheral surface of the outer ring 100A is provided with a large diameter portion 130 to which the buffer unit 400 is fixed. In this embodiment, the inner wall surfaces of the multiple protrusions 120 serve to position the buffer unit 400. In addition, the outer peripheral surface of the inner ring 200A is provided with a small diameter portion 230 to which the buffer unit 400 is fixed. In this embodiment, the inner wall surfaces of the multiple protrusions 220 serve to position the buffer unit 400. With the above configuration, the buffer unit 400 is positioned with high precision.

[0028] The helical gear 10A according to this embodiment has a tilt suppression structure that suppresses tilt of the outer ring 100A relative to the inner ring 200A (tilt relative to the central axis) while allowing relative rotation between the outer ring 100A and the inner ring 200A within a certain range. More specifically, a buffer unit 400 is fixed to the inner peripheral surface (large diameter portion 130) of the outer ring 100A and the outer peripheral surface (small diameter portion 230) of the inner ring 200A. The buffer unit 400 is provided on the outer ring 100A so as to slide against a wall surface (wall surface of the protrusion 120) perpendicular to the central axis, and is provided on the inner ring 200A so as to be fixed against a wall surface (wall surface of the protrusion 220) perpendicular to the central axis. The above configuration forms a tilt suppression structure.

[0029] The buffer unit 400 is composed of a first reinforcing ring 410, a second reinforcing ring 420, a dry bearing 430, and the above-mentioned elastic buffer 440. The elastic buffer 440 is made of an elastomer material (such as rubber), and is fixed to the inner circumferential surface of the first reinforcing ring 410 and the outer circumferential surface of the second reinforcing ring 420 by vulcanization bonding or the like.

[0030] The first reinforcing ring 410 is an annular member made of metal or the like. The outer peripheral surface of the first reinforcing ring 410 is fixed to the inner peripheral surface of the outer ring 100A by press fitting, and an elastic buffer 440 is attached to the inner peripheral surface. and an inward flange portion 412 provided at the end of the first cylindrical portion 411.

[0031] Second reinforcing ring 420 is an annular member made of metal, etc. Second reinforcing ring 420 has an inner circumferential surface fixed to the outer circumferential surface of inner ring 200A by press fitting, and has second cylindrical portion 421 to which elastic buffer 440 is fixed on the outer circumferential surface.

[0032] Dry bearing 430 is an annular member having a third cylindrical portion 431 and an outward flange portion 432 provided at the end of third cylindrical portion 431. The inner circumferential surface of third cylindrical portion 431 is fixed by press fitting to the outer circumferential surface of inner ring 200A, and is sandwiched between the inner circumferential surface of large-diameter cylindrical portion 422 of second reinforcing ring 420 excluding second cylindrical portion 421 and the outer circumferential surface of inner ring 200A. Outward flange portion 432 is provided so as to slide against both a wall surface (wall surface of protrusion 120) provided on outer ring 100A and perpendicular to the central axis, and inward flange portion 412.

[0033] <Advantages of the helical gear according to this embodiment> The helical gear 10A according to this embodiment can transmit rotational motion between a member (such as a rotating shaft) to which the inner ring 200A is fixed and a member (such as a gear) that meshes with the teeth 110 of the outer ring 100A. In the case of low torque, rotational motion is transmitted between the outer ring 100A and the inner ring 200A via the elastic buffer 440. Furthermore, by providing an anti-rotation structure, when torque above a certain level is applied, rotational motion is transmitted directly between the outer ring 100A and the inner ring 200A. Furthermore, the provision of the elastic buffer 440 reduces vibrations through a damping effect, thereby suppressing noise.

[0034] Furthermore, the tilt suppression structure suppresses tilt of the outer ring 100A relative to the inner ring 200A (tilt relative to the central axis). That is, in the helical gear 10A, an external force (a force in the rotational direction) acts on the multiple teeth 110 of the outer ring 100A, causing a force to act on the outer ring 100A that twists the outer ring 100A. This causes the outer ring 100A to tilt relative to the inner ring 200A, but the tilt suppression structure can suppress tilt of the outer ring 100A. This suppresses the generation of abnormal noise, further reducing noise.

[0035] In this embodiment, a configuration is shown in which a dry bearing 430 is provided that is fixed to the inner ring 200A and slides relative to the outer ring 100A. However, a configuration can also be used in which a dry bearing is provided that is fixed to the outer ring 100A and slides relative to the inner ring 200A. When this configuration is used, the buffer unit 400 is fixed to a wall surface (wall surface of the protrusion 120) that is provided on the outer ring 100A and perpendicular to the central axis, and slides relative to a wall surface (wall surface of the protrusion 220) that is provided on the inner ring 200A and perpendicular to the central axis. [Explanation of symbols]

[0036] 10,10A helical gear 100,100A outer ring 110 teeth 120 protrusions 130 Large diameter part 140 Step surface 150 Wall 200,200A inner ring 220 protrusion 230 Small diameter section 240 Step surface 250 Wall 300 Elastic buffer 400 Buffer Unit 410 First Reinforcement Ring 411 First cylindrical section 412 Inward flange 420 Second Reinforcement Ring 421 Second cylindrical section 422 Large diameter cylindrical part 430 dry bearing 431 Third cylindrical section 432 Outward flange 440 Elastic buffer

Claims

1. an outer ring having a plurality of teeth on an outer periphery; an inner ring disposed concentrically inside the outer ring; an annular elastic buffer disposed between the outer ring and the inner ring; Equipped with A rotation prevention structure is provided between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to limit relative rotation between the outer ring and the inner ring within a certain range, a helical gear having a tilt suppression structure that suppresses tilt of the outer ring relative to the inner ring while allowing relative rotation between the outer ring and the inner ring within a certain range, a buffer unit having the elastic buffer body; a buffer unit fixed to the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and arranged to slide against either a wall surface of the outer ring that is perpendicular to the central axis or a wall surface of the inner ring that is perpendicular to the central axis, thereby forming the tilt suppression structure.

2. The buffer unit comprises: a first reinforcing ring including a first cylindrical portion whose outer peripheral surface is fixed to the inner peripheral surface of the outer ring by press fitting and whose inner peripheral surface has the elastic buffer fixed thereto, and an inward flange portion provided at an end of the first cylindrical portion; a second reinforcing ring having an inner circumferential surface fixed to the outer circumferential surface of the inner ring by press fitting and a second cylindrical portion to which the elastic buffer is fixed on the outer circumferential surface; a dry bearing including: a third cylindrical portion whose inner peripheral surface is fixed to the outer peripheral surface of the inner ring by press fitting and which is sandwiched between the outer peripheral surface of the inner ring and the inner peripheral surface of a large-diameter cylindrical portion of the second reinforcing ring excluding the second cylindrical portion; and an outward flange portion which is provided at an end of the third cylindrical portion and is provided so as to slide against both a wall surface which is provided on the outer ring and which is perpendicular to the central axis, and the inward flange portion; 2. The helical gear according to claim 1, further comprising:

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