Gear structure and gear mechanism

Abstract

To reduce gear noise while maintaining rigidity of a gear member.SOLUTION: A gear structure 10 includes a gear member 20 having a plurality of gear teeth 22 provided on an outer peripheral surface 21, and a fastening member 30 surrounding the gear member 20 and fastening the plurality of gear teeth 22 to the inner side.SELECTED DRAWING: Figure 1

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 in that the rigidity of the gears is reduced by forming an annular groove on the surface, which results in a decrease in reliability of torque transmission between the gears. In consideration of the above circumstances, one aspect of the present disclosure aims to reduce gear noise while maintaining the rigidity of the gear members. [Means for solving the problem]

[0005] In order to solve the above problems, a gear structure according to one aspect of the present disclosure comprises a gear member having a plurality of gear teeth arranged on an outer peripheral surface thereof, and a fastening member that surrounds the gear member and fastens the plurality of gear teeth inwardly.

[0006] A gear mechanism according to one embodiment of the present disclosure comprises a first gear structure and a second gear structure that mesh with each other, the first gear structure including a first gear member having a plurality of first gear teeth disposed on an outer circumferential surface thereof, and a first fastening member that surrounds the first gear member and fastens the plurality of first gear teeth inwardly. [Brief description of the drawings]

[0007] [Figure 1] 1A and 1B are a front view and a side view of a gear structure according to an embodiment. [Diagram 2] FIG. 2 is an enlarged perspective view of a portion of the gear structure. [Diagram 3] FIG. 2 is a front view focusing on one gear tooth. [Figure 4] FIG. 2 is a front view of the gear mechanism according to the embodiment. [Diagram 5] This shows the frequency characteristics of the operating sound of a gear mechanism. [Figure 6] 1 is a chart showing the results of measuring the operating noise of a gear mechanism. [Figure 7] FIG. 11 is a plan view of a fastening member in a modified example. [Figure 8] FIG. 11 is a front view focusing on one gear tooth in a modified example. [Figure 9] FIG. 13 is an explanatory diagram of the operation of the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 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.

[0009] A: Gear structure 10 1 is a front view and a side view of a gear structure 10 according to one embodiment of the present disclosure. The gear structure 10 is a rotating body fixed to a shaft member 12. The shaft member 12 is a cylindrical shaft that can rotate about a rotation axis C. The shaft member 12 may be understood as an element of the gear structure 10.

[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, the gear structure 10 includes a gear member 20 and a fastening member 30. The gear member 20 is a disk-shaped spur gear. A plurality of gear teeth 22 are provided on an outer peripheral surface 21 of the gear member 20 at equal intervals along the circumferential direction.

[0012] The fastening member 30 is an elastic body that surrounds the gear member 20. Specifically, the fastening member 30 is an annular elastic body that surrounds the gear member 20 over the entire circumference. That is, the fastening member 30 is formed in an annular shape along the outer circumferential surface 21 and faces the outer circumferential surface 21. For example, an O-ring having a circular cross-sectional shape is exemplified as the fastening member 30. The fastening member 30 is integrally molded, for example, from various rubber materials.

[0013] The fastening member 30 is fixed to the gear member 20 with a clamping margin. That is, the fastening member 30 is installed on the gear member 20 in a state in which the diameter of the fastening member 30 is expanded compared to the state before installation. Therefore, the fastening member 30 is installed on the gear member 20 while maintaining a predetermined binding force, and fastens the multiple gear teeth 22 inward.

[0014] Fig. 2 is an enlarged perspective view of a portion of the gear structure 10. Fig. 3 is a front view focusing on one gear tooth 22. As illustrated in Figs. 2 and 3, a mounting groove 24 is formed in the tooth tip surface 23 of each of the gear teeth 22. The mounting groove 24 is a recess recessed into the tooth tip surface 23 of each gear tooth 22. The mounting groove 24 is formed in each of the gear teeth 22 at the same position in the direction of the rotation axis C (i.e., the width direction of the gear member 20).

[0015] 1 to 3 show a side surface 25 and a side surface 26 of the gear member 20. The side surface 25 and the side surface 26 are surfaces facing opposite each other in the direction of the rotation axis C. As illustrated in Fig. 1 to 3, the mounting groove 24 is formed at a position closer to the side surface 25 than to the side surface 26 in the direction of the rotation axis C. Specifically, the mounting groove 24 is formed between the midpoint of the gear member 20 in the direction of the rotation axis C and the side surface 25.

[0016] 2 and 3, the fastening member 30 fits into the mounting groove 24 of each of the gear teeth 22. Specifically, the fastening member 30 surrounds the gear member 20 while contacting the bottom surface of the mounting groove 24 of each gear tooth 22. Therefore, the fastening member 30 is installed at a position closer to the side surface 25 than to the side surface 26 in the direction of the rotation axis C. As illustrated in FIG. 3, the fastening member 30 protrudes outward from the tooth tip surface 23 of each gear tooth 22. As described above, in this embodiment, since the fastening member 30 fits into the mounting groove 24 of each gear tooth 22, the possibility that the fastening member 30 will fall off the gear member 20 can be reduced compared to, for example, a configuration in which the mounting groove 24 is not formed.

[0017] B: Gear mechanism 100 Fig. 4 is a front view of a gear mechanism 100 using the gear structure 10 exemplified above. As exemplified in Fig. 4, the gear mechanism 100 includes a gear structure 10a and a gear structure 10b that mesh with each other. The gear structure 10a and the gear structure 10b are the gear structures 10 exemplified in Figs. 1 to 3. The subscript a is added to each element of the gear structure 10a, and the subscript b is added to each element of the gear structure 10b.

[0018] Specifically, the gear structure 10a includes a gear member 20a having a plurality of gear teeth 22a disposed on an outer peripheral surface 21a, and a fastening member 30a that surrounds the gear member 20a and fastens the plurality of gear teeth 22a to the inside. The gear structure 10a is an example of a "first gear structure," the gear member 20a is an example of a "first gear member," the gear teeth 22a are an example of a "first gear teeth," and the fastening member 30a is an example of a "first fastening member."

[0019] Similarly, the gear structure 10b includes a gear member 20b having a plurality of gear teeth 22b disposed on an outer peripheral surface 21b, and a fastening member 30b that surrounds the gear member 20b and fastens the plurality of gear teeth 22b to the inside. The gear structure 10b is an example of a "second gear structure," the gear member 20b is an example of a "second gear member," the gear teeth 22b are an example of a "second gear teeth," and the fastening member 30b is an example of a "second fastening member."

[0020] The rotation axis Ca of the gear structure 10a and the rotation axis Cb of the gear structure 10b extend parallel to each other with a gap therebetween. In Fig. 4, directions Z1 and Z2 that are parallel to the rotation axis C (Ca, Cb) and face opposite each other are shown. The gear structure 10a is installed so that the side surface 25a of the gear member 20a faces the Z1 direction. On the other hand, the gear structure 10b is installed so that the side surface 25b of the gear member 20b faces the Z2 direction. In other words, the side surface 25a of the gear structure 10a and the side surface 25b of the gear structure 10b face in opposite directions to each other.

[0021] The position of the gear structure 10a and the position of the gear structure 10b differ in the direction of the rotation axis C. Specifically, the position of the gear structure 10a in the direction of the rotation axis C is shifted in the Z1 direction from the position of the gear structure 10b. The range Rc in the direction of the rotation axis C is a range where the gear structure 10a and the gear structure 10b overlap each other.

[0022] In the direction of the rotation axis C, the side surface 25a of the gear structure 10a is located further in the Z1 direction than the side surface 26b of the gear structure 10b. The range Ra in FIG. 4 is the range of the gear structure 10a that does not overlap with the gear structure 10b in the direction of the rotation axis C. That is, the range Ra is the range between the side surface 25a of the gear structure 10a and the side surface 26b of the gear structure 10b. Therefore, the range Ra is located further in the Z1 direction than the range Rc. The fastening member 30a of the gear structure 10a is installed within the range Ra. That is, the fastening member 30a does not overlap with the gear structure 10b in the direction of the rotation axis C.

[0023] Also, in the direction of the rotation axis C, the side surface 25b of the gear structure 10b is located further in the Z2 direction than the side surface 26a of the gear structure 10a. The range Rb in FIG. 4 is the range of the gear structure 10b that does not overlap with the gear structure 10a in the direction of the rotation axis C. That is, the range Rb is the range between the side surface 25b of the gear structure 10b and the side surface 26a of the gear structure 10a. Therefore, the range Rb is located further in the Z2 direction than the range Rc. The fastening member 30b of the gear structure 10b is installed within the range Rb. That is, the fastening member 30b does not overlap with the gear structure 10a in the direction of the rotation axis C.

[0024] Fig. 5 shows frequency characteristics of operation sounds generated by the operation of the gear mechanism 100. In Fig. 5, frequency characteristics of operation sounds are shown for this embodiment in which the fastening members 30a and 30b are provided, and for a configuration in which the fastening members 30a and 30b are not provided (hereinafter referred to as "comparative example").

[0025] Generally, in a mechanism in which multiple gears mesh, gear noises such as gear rattle noise caused by collision between gear teeth or meshing noise caused by deformation of the gear teeth due to load acting between the gear teeth are generated. As shown in Fig. 5, in the comparative example, a local peak P caused by the natural frequency of the gear member 20 is observed in the operating sound.

[0026] In contrast to the comparative example, according to this embodiment, the local peak P of the operating sound is significantly suppressed by providing the fastening member 30 that fastens the gear member 20. It is presumed that the gear noise is suppressed as described above because the vibration of each gear tooth 22 is suppressed by the fastening of the gear member 20 by the fastening member 30 or friction between the fastening member 30 and each gear tooth 22.

[0027] Fig. 6 is a table showing the results of measuring the operating sound of the gear mechanism 100 for multiple cases (Examples 1 to 4) in which the conditions of each gear structure 10 are changed. Fig. 6 shows the measured sound pressure of the operating sound and the difference (effect) compared to a control value for multiple cases in which (1) the inner diameter Φd of the fastening member 30, (2) the wire diameter W of the fastening member 30, and (3) the hardness of the fastening member 30 are different. The diameter (tooth tip diameter) of the gear member 20 being measured is 94 mm. The larger the inner diameter Φd of the fastening member 30, the smaller the tightening margin.

[0028] As can be seen from Fig. 6, Example 2 has the greatest effect in suppressing the operating noise. As can be seen from the comparison between Example 1 and Example 2, the smaller the tightening margin of the fastening member 30 (the larger the inner diameter Φd), the more the gear noise of the operating noise is reduced. Also, as can be seen from the comparison between Example 2 and Example 3, the lower the hardness Hs of the fastening member 30 (i.e., the softer it is), the more the gear noise of the operating noise is reduced. Furthermore, as can be seen from the comparison between Example 2 and Example 4, the larger the wire diameter W of the fastening member 30, the more the gear noise of the operating noise is reduced.

[0029] As can be seen from the above results, a configuration in which the tightening margin of the tightening member 30 is small, the hardness Hs of the tightening member 30 is low, or the wire diameter W of the tightening member 30 is large is advantageous for reducing gear noise. The degree of contribution to the effect of reducing gear noise is such that the wire diameter W of the tightening member 30 exceeds the hardness Hs, and the hardness Hs of the tightening member 30 exceeds the tightening margin.

[0030] As described above, in this embodiment, the fastening member 30 surrounds the gear member 20, thereby fastening the multiple gear teeth 22 inward. Therefore, it is possible to reduce gear noise while maintaining the rigidity of the gear member 20. In this embodiment, in particular, since the fastening member 30 surrounds the gear member 20 over the entire circumference, the effect of reducing gear noise is particularly remarkable.

[0031] Moreover, the fastening member 30a is installed within a range Ra where the gear structure 10a and the gear structure 10b do not overlap in the direction of the rotation axis C. That is, the fastening member 30a does not interfere with the gear structure 10b. Therefore, the fastening member 30a can reduce gear noise without affecting the rotation of the gear structure 10b. Similarly, the fastening member 30b is installed within a range Rb where the gear structure 10a and the gear structure 10b do not overlap in the direction of the rotation axis C, so the fastening member 30b can reduce gear noise without affecting the rotation of the gear structure 10a.

[0032] C: Modification 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.

[0033] (1) In the above embodiment, the mounting groove 24 is formed in each gear tooth 22, but the mounting groove 24 may be omitted. In other words, the tooth tip surface 23 of each gear tooth 22 may be a flat surface without irregularities over the entire width of the gear member 20.

[0034] (2) In the above embodiment, the fastening member 30 is made of a rubber material, but the fastening member 30 may be made of various resin materials. However, from the viewpoint of reducing gear noise, a rubber material is more suitable than a resin material for the fastening member 30.

[0035] (3) The shape of the fastening member 30 is not limited to the above examples. For example, in the above embodiment, an O-ring having a circular cross-sectional shape is exemplified as the fastening member 30, but an X-ring having an X-shaped cross-sectional shape or a D-ring having a D-shaped cross-sectional shape may be used as the fastening member 30.

[0036] (4) The planar shape of the fastening member 30 is also arbitrary and is not limited to the example in the above embodiment. For example, as illustrated in Fig. 7, a fastening member 30 having recesses 31 formed on its inner circumferential surface in a shape corresponding to the tip of each gear tooth 22 is also conceivable. Each gear tooth 22 of the gear member 20 fits into each recess 31 in Fig. 7. Therefore, in an embodiment using the fastening member 30 in Fig. 7, the mounting groove 24 may be omitted as described above.

[0037] In addition, in the above embodiment, an annular fastening member 30 is exemplified, but the planar shape of the fastening member 30 is not limited to annular, so long as it is a member capable of fastening the gear member 20. For example, the planar shape of the fastening member 30 may be an arc shape (C-shape) with a portion of the annular shape removed.

[0038] (5) In the above embodiment, the fastening member 30 molded separately from the gear member 20 is attached to the gear member 20, but the configuration and method for installing the fastening member 30 on the gear member 20 are not limited to the above example. For example, the fastening member 30 surrounding the gear member 20 may be formed by applying a liquid resin material to the outer circumferential surface 21 of the gear member 20 and then curing the resin material.

[0039] (6) In each of the above-described embodiments, the fastening member 30 protrudes outward from the tooth tip surfaces 23 of each gear tooth 22. However, as shown in FIG. 8, a configuration in which the outer peripheral surface of the fastening member 30 is in the same plane as the tooth tip surfaces 23 of each gear tooth 22, or a configuration in which the outer peripheral surface of the fastening member 30 is located lower than the tooth tip surfaces 23 of each gear tooth 22, is also contemplated.

[0040] (7) In the above embodiment, the gear structure 10a and the gear structure 10b of the gear mechanism 100 have the same structure, but the gear structure 10a and the gear structure 10b may have different shapes or dimensions. For example, the dimensions such as diameter or width may be different between the gear member 20a and the gear member 20b.

[0041] (8) In the above embodiment, the gear structure 10a and the gear structure 10b both have the fastening member 30 (30a, 30b), but it is also possible to assume a configuration in which only one of the gear structure 10a and the gear structure 10b has the fastening member 30. However, from the viewpoint of effectively reducing gear noise, a configuration in which both the gear structure 10a and the gear structure 10b have the fastening member 30 (30a, 30b) is preferable.

[0042] (9) Fig. 9 is an enlarged front view of the meshing portion of the gear structure 10a and the gear structure 10b. Fig. 9 illustrates the gap δ between the fastening member 30a of the gear structure 10a and the side surface 26b of the gear member 20b. Lubricating oil is supplied or filled into the meshing portion of the gear structure 10a and the gear structure 10b.

[0043] In a configuration in which the gap δ is sufficiently small, for example, torque applied to the gear structure 10b can be transmitted to the gear structure 10a via the lubricating oil. Specifically, the shear stress applied to the lubricating oil from the gear structure 10b is transmitted to the gear structure 10a. Therefore, compared to a configuration in which the gap δ is large enough that transmission of the shear stress is not expected, the difference in rotational speed between the gear structures 10a and 10b is reduced. With the above configuration, gear noise caused by collision between each gear tooth 22a of the gear structure 10a and each gear tooth 22b of the gear structure 10b can be reduced.

[0044] In the above explanation, attention has been focused on the gap δ between the fastening member 30a of the gear structure 10a and the side surface 26b of the gear member 20b. However, it is similarly desirable that the gap δ between the fastening member 30b of the gear structure 10b and the side surface 26a of the gear member 20a be small from the viewpoint of reducing the rotational speed difference.

[0045] (9) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element in the description and does not have any substantial meaning. Therefore, there is no room for restrictive interpretation of the position of each element or the order of production, etc., based on the term "nth".

[0046] D: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0047] A gear structure according to one embodiment (embodiment 1) of the present disclosure includes a gear member having a plurality of gear teeth on its outer circumferential surface, and a fastening member that surrounds the gear member and fastens the plurality of gear teeth inward. In the above embodiment, the fastening member surrounds the gear member, thereby fastening the plurality of gear teeth inward. Therefore, it is possible to reduce gear noise while maintaining the rigidity of the gear member.

[0048] In a specific example (Aspect 2) of Aspect 1, a mounting groove is formed on the tooth tip surface of each of the plurality of gear teeth, and the fastening member fits into the mounting groove of each of the plurality of gear teeth. In the above aspect, the fastening member fits into the mounting groove of each gear tooth. Therefore, it is possible to reduce the possibility that the fastening member falls off the gear member.

[0049] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the fastening member is an annular elastic body. In the above aspect, since the fastening member surrounds the gear member over the entire circumference, the effect of reducing gear noise is particularly remarkable compared to, for example, a fastening member formed into an arc shape (C-shape) with part of the annular shape removed.

[0050] A gear mechanism according to one aspect (aspect 4) of the present disclosure includes a first gear structure and a second gear structure that mesh with each other, and the first gear structure includes a first gear member having a plurality of first gear teeth on its outer circumferential surface, and a first fastening member that surrounds the first gear member and fastens the plurality of first gear teeth inward. In the above aspect, the first fastening member surrounds the first gear member, thereby fastening the plurality of first gear teeth inward. Therefore, gear noise can be reduced while maintaining the rigidity of the first gear member.

[0051] In a specific example (aspect 5) of aspect 4, the first fastening member is installed within a range of the first gear member that does not overlap with the second gear structure in the direction of the rotation axis. In the above aspect, since the first fastening member does not interfere with the second gear structure, the first fastening member can reduce gear noise without affecting the rotation of the second gear structure.

[0052] In a specific example (aspect 6) of aspect 4 or aspect 5, the second gear structure includes a second gear member having a plurality of second gear teeth on its outer circumferential surface, and a second fastening member surrounding the second gear member and fastening the plurality of second gear teeth to the inside. In the above aspect, in addition to the first fastening member surrounding the first gear member, a second fastening member surrounding the second gear member is also installed. Therefore, the effect of reducing gear noise is particularly remarkable compared to a configuration in which the second fastening member is not installed.

[0053] In a specific example (aspect 7) of aspect 6, the second fastening member is installed within a range of the second gear member that does not overlap with the first gear structure in the direction of the rotation axis. In the above aspect, since the second fastening member does not interfere with the first gear structure, the second fastening member can reduce gear noise without affecting the rotation of the first gear structure. [Explanation of symbols]

[0054] 10, 10a, 10b... gear structure, 12... shaft member, 20, 20a, 20b... gear member, 21... outer peripheral surface, 22, 22a, 22b... gear teeth, 23... tooth tip surface, 24, 24a, 24b... mounting groove, 25, 25a, 25b... side surface, 26, 26a, 26b... side surface, 30, 30a, 30b... fastening member, 100... gear mechanism.

Claims

1. a gear member having a plurality of gear teeth disposed on an outer circumferential surface thereof; a clamping member surrounding the gear member and clamping the plurality of gear teeth inwardly; A gear structure comprising:

2. A mounting groove is formed on a tooth tip surface of each of the plurality of gear teeth, The fastening member fits into the mounting groove in each of the plurality of gear teeth. The gear structure of claim 1.

3. The fastening member is an annular elastic body. The gear structure according to claim 1 or 2.

4. The gear mechanism includes a first gear structure and a second gear structure that mesh with each other, The first gear structure includes: a first gear member having a plurality of first gear teeth disposed on an outer circumferential surface thereof; a first clamping member surrounding the first gear member to inwardly clamp the plurality of first gear teeth; A gear mechanism including:

5. The first fastening member is disposed within a range of the first gear member that does not overlap with the second gear structure in the direction of the rotation axis.

5. The gear mechanism of claim 4.

6. The second gear structure includes: a second gear member having a plurality of second gear teeth disposed on an outer circumferential surface thereof; a second clamping member surrounding the second gear member to inwardly clamp the plurality of second gear teeth; 6. A gear mechanism according to claim 4 or claim 5, comprising:

7. The second fastening member is disposed within a range of the second gear member that does not overlap with the first gear structure in the direction of the rotation axis. The gear mechanism of claim 6.

Images