JP7435226B2 - gear - Google Patents

Description

The present invention relates to gears.

The gear includes a metal bush, a resin member provided around the metal bush and having teeth formed on the outer periphery, and an elastic member provided between the metal bush and the resin member. is known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2017-015100

By the way, in recent years, with the increasing demand for low noise in gears, it is required to suppress rattling noise (also referred to as meshing noise) generated when gears mesh. Although various measures can be taken to suppress rattling noise, there is a risk that the strength of the gear will be reduced due to these measures.

An object of one aspect of the present invention is to provide a gear that can suppress rattling noise while maintaining the strength of the gear.

A gear according to one aspect of the present invention includes a gear body having a plurality of teeth on the outer periphery, and a low elastic member having a lower elastic modulus than the gear body, which is provided at least inside the teeth so as not to be exposed from the tooth surface. , is provided.

In this gear, since the low-elasticity member exists inside the tooth portion, the tooth portion itself where tooth rattle noise is generated can have a damping effect, and the rattle noise can be effectively suppressed. In addition, since the low-elasticity member is provided so as not to be exposed from the tooth surface, it is possible to suppress the decrease in tooth surface strength due to the presence of the low-elasticity member inside the tooth portion, and as a result, , it is possible to prevent the strength of the gear from decreasing. Therefore, it is possible to suppress rattling noise while maintaining the strength of the gear.

In the gear according to one aspect of the present invention, the low elastic member may be disposed only inside the tooth portion. This configuration makes it easier to maintain the strength of the gear.

In the gear according to one aspect of the present invention, the low elastic member may be provided inside all of the teeth among the plurality of teeth. With this configuration, rattling noise can be further suppressed. Moreover, it becomes easier to ensure symmetry around the axis of the gear.

In the gear according to one aspect of the present invention, the low elasticity member may be provided inside every N tooth portions (N is an integer of 1 or more). This configuration makes it easier to maintain the strength of the gear. Moreover, it becomes easier to ensure symmetry around the axis of the gear.

In the gear according to one aspect of the present invention, the low elastic member may be provided so as to be exposed from at least one of the end surface and the top surface of the tooth portion. With this configuration, for example, it is easy to fill the inside of the tooth portion with the low elastic member, and it is possible to easily provide the low elastic member.

According to the present invention, it is possible to provide a gear that can suppress rattling noise while maintaining the strength of the gear.

FIG. 1 is a perspective view of a gear according to a first embodiment. FIG. 2(a) is a perspective view showing a method for manufacturing the gear shown in FIG. FIG. 2(b) is a perspective view continuing from FIG. 2(a). FIG. 3(a) is a sectional view continuing from FIG. 2(b). FIG. 3(b) is a sectional view continuing from FIG. 3(a). FIG. 4(a) is a perspective view continuing from FIG. 3(b). FIG. 4(b) is a perspective view continuing from FIG. 4(a). FIG. 4(c) is a perspective view continuing from FIG. 4(b). FIG. 5 is a perspective view of a gear according to the second embodiment. FIG. 6(a) is a perspective view showing a method of manufacturing the gear shown in FIG. FIG. 6(b) is a perspective view continuing from FIG. 6(a). FIG. 7(a) is a perspective view continuing from FIG. 6(b). FIG. 7(b) is a perspective view continuing from FIG. 7(a). FIG. 8 is an enlarged perspective view of a part of a gear according to a modification. FIG. 9 is an enlarged perspective view of a part of a gear according to another modification. FIG. 10 is an enlarged perspective view of a part of a gear according to still another modification.

Embodiments will be described in detail below with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are given the same reference numerals, and redundant description will be omitted.

[First embodiment]
A first embodiment will be described. As shown in FIGS. 1 and 2, the gear 1 according to the first embodiment is a metal gear, and is used as a vehicle or industrial gear. For example, the gear 1 can be used as a balance shaft gear, a camshaft gear, etc. in an engine. The gear 1 includes a gear body 3 and a low elastic member 5. Gear 1 is a spur gear.

The gear body 3 is, for example, a member attached to a rotating shaft (not shown). The gear body 3 is a member that meshes with other gears. The gear body 3 is made of metal such as stainless steel, for example. The gear main body 3 has a main body part 7 and a plurality of tooth parts 9. The main body portion 7 is annular. The main body portion 7 is provided with a through hole 7h. The through hole 7h passes through one end surface and the other end surface of the main body portion 7. A rotating shaft is inserted into the through hole 7h. A plurality of tooth portions 9 are provided on the outer periphery of the main body portion 7. A plurality of tooth portions 9 are formed at predetermined intervals in the circumferential direction of the main body portion 7 . A hole 11 is provided in each of the plurality of teeth 9. The hole 11 passes through one end surface 9a and the other end surface 9b of the tooth portion 9. The hole 11 here is a circular hole. The hole 11 is provided only in the tooth portion 9 and not in the main body portion 7.

The low elastic member 5 is a member that attenuates rattling noise generated when the gear 1 meshes with another gear. The low elasticity member 5 is provided in the hole 11 of the plurality of teeth 9. That is, the low elastic member 5 is provided at least inside the tooth portion 9 so as not to be exposed from the tooth surface 9f. The low elasticity member 5 has a lower elastic modulus than the gear body 3. The low elasticity member 5 is made of rubber, for example. Rubbers include butadiene rubber, chloroprene rubber, butyl rubber, styrene-butadiene rubber, nitrile rubber, ethylene propylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, silicone rubber, and the like. From the viewpoints of durability and heat resistance, the rubber is preferably fluororubber or silicone rubber.

In the illustrated example, the low elastic member 5 is provided inside all of the teeth 9 among the plurality of teeth 9. The low elastic member 5 is provided only inside the tooth portion 9 and is not provided in the main body portion 7. The low elasticity member 5 is filled inside the hole 11 without any gaps. The low elastic member 5 is provided so as to be flush with the end surfaces 9a and 9b of the tooth portion 9. The low elasticity member is provided so as to be exposed from the end surface 9a and the end surface 9b of the tooth portion 9.

Next, an example of a method for manufacturing the gear 1 will be described.

The method for manufacturing the gear 1 according to the present embodiment includes a metal member processing step, a hole processing step, an elastic member forming step, and a gear cutting step. Each step will be explained in order below.

<Metal parts processing process>
In the metal member processing step, an annular metal member 20 is formed as shown in FIG. 2(a). In the metal member processing step, the metal member 20 is cut to adjust the dimensions of the metal member 20. In the metal member processing step, the metal member 20 is cut using a machine tool such as a lathe. Specifically, in the metal member processing step, the outer diameter portion and the inner diameter side surface of the metal member 20 are cut to process the metal member 20 into predetermined dimensions. After cutting the metal member 20, the metal member 20 is cleaned.

<Hole processing process>
In the hole processing step, as shown in FIG. 2(b), hole processing is performed to form a plurality of holes 11 in the outer peripheral portion of the metal member 20. For example, in the hole machining process, a plurality of holes 11 are formed in the outer circumference of the metal member 20 so as to be lined up along the circumferential direction using a drill of a machine tool such as a drilling machine.

<Elastic member forming process>
In the elastic member forming step, the low elastic member 5 is formed in the hole 11 of the metal member 20. For example, in the elastic member forming step, a metal member 20 in which a plurality of holes 11 are formed is placed in a lower mold 31, as shown in FIG. 3(a). Subsequently, as shown in FIG. 3(b), the rubber material G is pushed into the hole 11 by the upper mold 32, and the rubber material G is injected into the hole 11 to fill it. Then, the filled rubber material G is vulcanized and heated. As a result, the low elastic member 5 is formed in the hole 11 of the metal member 20, as shown in FIG. 4(a). If necessary, burrs on the low elastic member 5 are removed.

<Gear cutting process>
In the gear cutting process, as shown in FIGS. 4(b) and 4(c), the gear cutting process of the metal member 20 is performed while aligning the positions of the low elastic member 5 and the tooth portion 9. conduct. Applicable gear cutting operations include finishing operations using a hobbing machine or a shaving machine. Through the gear cutting process, the tooth portion 9 including the low elastic member 5 inside is formed so that the low elastic member 5 is exposed from the end surfaces 9a and 9b, and the low elastic member 5 is not exposed from the tooth surface 9f. Ru. Through the above steps, the gear 1 is manufactured. The method for manufacturing the gear 1 is not limited to the method described above, and various known methods can be used.

As explained above, in the gear 1 according to the present embodiment, since the low elastic member 5 is present inside the tooth portion 9, the tooth portion 9 itself that generates rattling noise can have a damping effect. , the rattling noise can be effectively suppressed. In addition, since the low elastic member 5 is provided so as not to be exposed from the tooth surface 9f, the reduction in tooth surface strength due to the presence of the low elastic member 5 inside the tooth portion 9 can be suppressed. This makes it possible to prevent the strength of the gear 1 from decreasing. Therefore, it is possible to suppress rattling noise while maintaining the strength of the gear 1.

In the gear 1, the low elastic member 5 is disposed only inside the tooth portion 9. With this configuration, the strength of the gear 1 can be easily maintained.

In the gear 1, the low elastic member 5 is provided inside all of the teeth 9 among the plurality of teeth 9. With this configuration, rattling noise can be further suppressed. Further, symmetry around the axis of the gear 1 can be easily ensured.

In the gear 1, the low elastic member 5 is provided so as to be exposed from the end surface 9a and the end surface 9b of the tooth portion 9. With this configuration, compared to a case where the low elastic member 5 is not exposed at all, it is easier to fill the inside of the tooth portion 9 with the low elastic member 5, and the low elastic member 5 can be easily provided.

A demonstration test regarding the effect of reducing tooth rattling noise of the gear 1 will be explained. In the demonstration test, gear 1 was used as Example 1, a gear similar to Gear 1 except that it did not include the low elastic member 5 and hole 11 was used as a comparative example, and the rattling sound (dB) of Example 1 and the comparative example was measured. and compared. The rattling sound was measured using a known measurement method (the same applies to the following demonstration tests). The rotational speed of both Example 1 and Comparative Example at the time of measuring tooth rattle noise was 6000 rpm. As a result of the demonstration test, it was confirmed that in Example 1, rattling noise could be reduced by about 20% compared to the comparative example.

[Second embodiment]
A second embodiment will be described. In the description of this embodiment, differences from the first embodiment will be explained, and redundant explanation will be omitted.

As shown in FIG. 5, the gear 101 according to the second embodiment is provided with the low elastic member 5 exposed also from the top surface 9y of the tooth portion 9. (see). Each of the plurality of teeth 9 is provided with a hole 12 that communicates with the hole 11 . The hole 12 opens on the top surface 9y of the tooth portion 9 and extends in the radial direction. The hole 12 here is a circular hole having a smaller diameter than the hole 11. The low elasticity member 5 is further provided in the hole 12 of the plurality of teeth 9. The low elasticity member 5 is filled inside the hole 12 without any gaps. The low elasticity member 5 is provided so as to be flush with the top surface 9y of the tooth portion 9.

In the manufacturing method of the gear 101 of this embodiment, in the hole machining process, as shown in FIGS. After forming, a hole 12 is formed so as to communicate with the hole 11 of the metal member 20. In the elastic member forming step, a rubber material is forced into the holes 11 and 12 using an upper mold and a lower mold, the rubber material is injected and filled into the holes 11 and 12, and the rubber material is vulcanized and heated. Thereby, as shown in FIG. 7(a), low elastic members 5 are formed in the holes 11 and 12 of the metal member 20. In the gear cutting process, the tooth portion 9 including the low elastic member 5 is cut so that the low elastic member 5 is exposed from the end surface 9a, the end surface 9b, and the top surface 9y, and the low elastic member 5 is not exposed from the tooth surface 9f. (see FIG. 7(b)).

As described above, also in the gear 101 according to the present embodiment, it is possible to suppress rattling noise while maintaining its strength. Further, in the gear 101, the low elastic member 5 is provided so as to be exposed from the top surface 9y of the tooth portion 9. With this configuration, it becomes easier to fill the inside of the tooth portion 9 with the low elastic member 5, and it becomes possible to provide the low elastic member 5 even more easily.

[Modified example]
Although the embodiments have been described above, one aspect of the present invention is not necessarily limited to the above embodiments, and various changes can be made without departing from the gist thereof.

In the above embodiment, the low elasticity member 5 is provided only inside the toothed portion 9, but as in the gear 201 shown in FIG. Good too. For example, the low elasticity member 5 may extend radially inward from the inside of the tooth portion 9 and reach the inside of the main body portion 7 .

In the above embodiment, the size and range of the low elastic member 5 are not particularly limited. For example, like the gear 301 shown in FIG. 9, the low elastic member 5 may be provided so that the portion exposed to the end surface 9a and the end surface 9b and the portion exposed to the top surface 9y are continuous. The low elastic member 5 of the gear 301 has a plate shape and is configured to be embedded in the tooth portion 9 while being exposed at the end surface 9a, the end surface 9b, and the top surface 9y.

A demonstration test regarding the effect of reducing rattling noise of the gear 301 will be explained. Here, the gear 301 is taken as Example 2, and the tooth rattle noise (dB) of Example 2 and the above comparative example was measured and compared. The rotational speed of both Example 2 and Comparative Example at the time of measuring rattling noise was 6000 rpm. As a result of the demonstration test, it was confirmed that in Example 2, rattling noise could be reduced by about 10% compared to the comparative example.

Further, for example, like a gear 401 shown in FIG. 10, the low elastic member 5 may extend radially inward from the gear 301 (see FIG. 9) and reach the inside of the main body portion 7. A demonstration test regarding the effect of reducing rattling noise of the gear 401 will be explained. Here, the gear 401 is used as Example 3, and the tooth rattle noise (dB) of Example 3 and the above comparative example was measured and compared. The rotational speed of both Example 3 and Comparative Example at the time of measuring rattling noise was 6000 rpm. As a result of the demonstration test, it was confirmed that in Example 3, rattling noise could be reduced by about 8% compared to the comparative example.

In the embodiment described above, the low elastic members 5 are provided inside all the tooth portions 9, but the low elastic members 5 are provided inside every N tooth portions 9 (N is an integer greater than or equal to 1). Good too. With this configuration, the strength of the gear 1 can be easily maintained. Further, symmetry around the axis of the gear 1 can be easily ensured. Note that the low elastic member 5 only needs to be provided inside at least one of the plurality of teeth 9.

In the above embodiment, the low elastic member 5 does not need to be exposed from at least one of the end surface 9a, the end surface 9b, and the top surface 9y of the tooth portion 9. In the above embodiment, the gear 1 is a spur gear, but the gear 1 may be a helical gear or the like. In the above embodiment, the low elasticity member 5 is made of rubber, but the low elasticity member 5 is not limited to rubber. The low elasticity member 5 may be any member having a lower modulus of elasticity than the gear body 3.

In the above embodiment, the gear 1 is a metal gear. However, the gear according to one aspect of the present invention may be a resin gear. The gear body of the resin gear includes an annular metal bush and an annular resin member provided around the metal bush and having teeth on the outer periphery. In this case, the low elasticity member has a lower elastic modulus than the resin member.

Each structure in the above embodiments and modified examples is not limited to the materials and shapes described above, and various materials and shapes can be applied. Each configuration in the above embodiment or modified example can be arbitrarily applied to each configuration in other embodiments or modified examples. Some of the configurations in the above embodiments or modified examples can be omitted as appropriate without departing from the gist of one aspect of the present invention.

1, 101, 201, 301, 401... Gear, 3... Gear main body, 5... Low elastic member, 9... Teeth, 9a, 9b... End surface, 9f... Tooth surface, 9y... Top surface.

Claims (5)

a gear body having a plurality of teeth on the outer periphery;
a low-elasticity member that is provided at least inside the tooth portion so as not to be exposed from the tooth surface and has a lower elastic modulus than the gear body ;
The tooth portion is provided with a hole passing through one end surface and the other end surface of the tooth portion,
The gear, wherein the low elasticity member is provided in the hole of the tooth and is not exposed from the top surface of the tooth . The gear according to claim 1, wherein the low elasticity member is disposed only inside the tooth portion. The gear according to claim 1 or 2, wherein the low elasticity member is provided inside all of the teeth of the plurality of teeth. The gear according to claim 1 or 2, wherein the low elasticity member is provided inside every N teeth (N is an integer of 1 or more) among the plurality of teeth. The gear according to any one of claims 1 to 4, wherein the low elasticity member is provided so as to be exposed from an end surface of the tooth portion.

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