Gear system

Abstract

A gear device (1) comprises: a first multilayer spur gear (10) in which a plurality of first spur gears (10A, 10B, 10C, 10D, 10E) are arranged in series on a first center axle and adjacent first spur gears are mutually displaced in a direction of rotation, the first spur gears rotating integrally about the first center axle; and a second multilayer spur gear (20) in which a plurality of second spur gears (20A, 20B, 20C, 20D) are arranged in series on a second center axle parallel to the first center axle and adjacent second spur gears are mutually displaced in the direction of rotation, the second spur gears rotating integrally about the second center axle.

Description

Cross-reference to Related Applications , , , ,

[0007] , , ,

[0005] , , , , , , , , , , , ,

[0006]

[0001] This international application claims priority based on Japanese Patent Application No. 2023-042070, filed with the Japan Patent Office on March 16, 2023, and incorporates by reference in its entirety the content of Japanese Patent Application No. 2023-042070 into this international application.

Technical Field

[0002] This disclosure relates to a gear device.

Background Art

[0003] For example, the gear described in Patent Document 1 constitutes one Schizars gear by fixing two spur gears with a phase shift to a shaft via an elastic material. Note that a spur gear refers to a gear whose tooth direction is parallel to the central axis.

[0004] As shown in FIG. 4 of Patent Document 1, when this Schizars gear meshes with another spur gear, the teeth of the other spur gear are sandwiched between the teeth of the two spur gears constituting the Schizars gear, thereby preventing the generation of abnormal noise caused by backlash.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] A gear device transmits rotational force by meshing at least two gears. At this time, when the rotational force of the gear on the input side fluctuates, vibration (hereinafter, this vibration is referred to as "meshing vibration") occurs in the gear device.

[0007] To suppress meshing vibrations, it is desirable to use helical gears for both gears. However, when helical gears transmit rotational force, a force parallel to the central axis, i.e., a thrust load, is inevitably generated.

[0008] In view of the above, this disclosure discloses an example of a gear system capable of suppressing meshing vibrations without using helical gears. [Means for solving the problem]

[0009] The gear device preferably comprises, for example, at least one of the following constituent elements: a first multilayer spur gear in which a plurality of first spur gears are arranged in series on a first central axis and adjacent first spur gears are offset from each other in the rotational direction, and these first spur gears rotate as a single unit around the first central axis; and a second multilayer spur gear in which a plurality of second spur gears are arranged in series on a second central axis parallel to the first central axis and adjacent second spur gears are offset from each other in the rotational direction, and these second spur gears rotate as a single unit around the second central axis.

[0010] Furthermore, it is desirable that each of the multiple first spur gears meshes with each of the corresponding multiple second spur gears.

[0011] As a result, for example, when rotational force is input to the first multilayer spur gear and transmitted to the second multilayer spur gear, if the rotational force of the first multilayer spur gear fluctuates, the vibration is distributed to multiple first spur gears with a time lag.

[0012] Therefore, compared to a case where the input gear consists of a single spur gear, for example, the vibrations generated in each of the multiple first spur gears are reduced, thus suppressing meshing vibrations. Furthermore, since the first multilayer spur gear and the second multilayer spur gear are gears in which multiple spur gears rotate as a single unit, thrust loads are not generated in principle.

[0013] Furthermore, in this gear system, each of the multiple first and second spur gears constituting the first and second multilayer spur gears rotates as a single unit. Therefore, unlike scissors gears, the meshing state of each first and second spur gear is the same as that of ordinary spur gears.

[0014] In other words, the gear device in question does not have a configuration in which "the teeth of the output spur gear are sandwiched between the teeth of the two input spur gears." Therefore, the gear device in question cannot produce the action of "sandwiching the teeth of one spur gear between the teeth of two spur gears," as described in Patent Document 1. Consequently, the gear device in question is an invention that is completely different in technical concept from the gear device described in Patent Document 1 (see Figure 4 of Patent Document 1), which meshes a scissors gear with a spur gear. [Brief explanation of the drawing]

[0015] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [Figure 1] This is a diagram showing a gear apparatus according to the first embodiment. [Figure 2] This is a diagram showing a gear apparatus according to the first embodiment. [Figure 3] This diagram shows the meshing state of spur gears. [Figure 4] This is a diagram showing a gear apparatus according to the second embodiment. [Figure 5] This is a diagram showing a first multilayer spur gear according to the third embodiment. [Explanation of symbols]

[0016] 1… Gear system 10… First multilayer spur gear 10A, 10B, 10C, 10D, 10E… First spur gear 20… Second multilayer spur gear 20A, 20B, 20C, 20D... Second spur gear [Modes for carrying out the invention]

[0017] The following embodiments of the invention show an example of embodiments belonging to the technical scope of the present disclosure. That is, the invention-specific matters described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

[0018] Note that the arrows, slashes, etc. indicating directions attached to each figure are described to facilitate understanding of the relationship between the figures and the shape of each member or part. Therefore, the invention shown in the present disclosure is not limited to the directions attached to each figure. The figure with slashes does not necessarily show a cross-sectional view.

[0019] At least the members or parts described with reference numerals are provided with at least one, unless otherwise stated such as "only one". That is, when there is no statement such as "only one", two or more of such members may be provided. The gear device shown in the present disclosure includes at least one of the components such as the members or parts described with reference numerals and the structural parts shown in the drawings.

[0020] (First Embodiment) <1. Overview of Gear Device> In the first embodiment, an example of the gear device according to the present disclosure is applied to a speed reducer that decelerates and transmits the rotational output of an electric motor. As shown in FIG. 1, the gear device 1 includes at least a first multi-layer spur gear 10 and a second multi-layer spur gear 20.

[0021] In this embodiment, the rotational force of an electric motor (not shown) is input to the first multi-layer spur gear 10. The second multi-layer spur gear 20 decelerates the rotational force received from the first multi-layer spur gear 10 and transmits it to the output side.

[0022] <2. Details of Multi-Layer Spur Gear> As shown in FIG. 1, the first multi-layer spur gear 10 has a plurality of (in this example, four) first spur gears 10A, 10B, 10C, 10D. The plurality of first spur gears 10A to 10D are arranged in series on the first central axis L1.

[0023] The first spur gears 10A to 10D are offset from each other in the rotational direction, and rotate as a single unit around the first central axis L1.

[0024] In this embodiment, for example, a rotation stopper (not shown) such as a spline or serration is provided on the shaft portion 11 of the first multilayer spur gear 10, and the first spur gears 10A to 10D are fitted into the rotation stopper in a phase-shifted state to constitute the first multilayer spur gear 10.

[0025] The second multilayer spur gear 20 has the same structure as the first multilayer spur gear 10, except for the number of teeth. That is, the second multilayer spur gear 20 also has multiple (four in this example) second spur gears 20A, 20B, 20C, and 20D. The multiple second spur gears 20A to 20D are arranged in series on a second central axis L2 (see Figure 2) parallel to the first central axis L1.

[0026] The second spur gears 20A to 20D are offset from each other in the rotational direction, and rotate as a single unit around the second central axis L2. Each of the multiple first spur gears 10A to 10D meshes with each of the corresponding multiple second spur gears 20A to 20D.

[0027] In other words, the first spur gear 10A meshes with the second spur gear 20A, the first spur gear 10B meshes with the second spur gear 20B, the first spur gear 10C meshes with the second spur gear 20C, and the first spur gear 10D meshes with the second spur gear 20D.

[0028] <3. Features of the gear apparatus according to the first embodiment> In the gear apparatus 1 according to this embodiment, when rotational force is input to the first multilayer spur gear 10 and transmitted to the second multilayer spur gear 20, the meshing of the first spur gear 10A and the second spur gear 20A, the meshing of the first spur gear 10B and the second spur gear 20B, the meshing of the first spur gear 10C and the second spur gear 20C, and the meshing of the first spur gear 10D and the second spur gear 20D are each staggered in time.

[0029] This time lag in meshing reduces the time that the first multilayer spur gear 10 and the second multilayer spur gear 20 are not meshing as a whole. In other words, vibrations generated between the multiple first spur gears 10A to 10D and the multiple second spur gears 20A to 20D are dispersed by the time lag in which the other spur gears mesh with each other.

[0030] Therefore, according to this embodiment, meshing vibrations can be suppressed compared to, for example, the case where the input gear is composed of a single spur gear. Furthermore, since the first multilayer spur gear 10 and the second multilayer spur gear 20 are gears in which multiple spur gears rotate as a single unit, thrust loads do not occur in principle.

[0031] In the gear device 1, the multiple first spur gears 10A to 10D and second spur gears 20A to 20D that make up the first multilayer spur gear 10 and the second multilayer spur gear 20 rotate as a single unit. Therefore, unlike scissors gears, the meshing state of each first spur gear 10A to 10D and each second spur gear 20A to 20D is the same as that of ordinary spur gears.

[0032] Therefore, in the gear device 1, as shown in Figure 3, there is backlash in the meshing portion between each first spur gear 10A to 10D and each second spur gear 20A to 20D, and it is not a configuration in which "the teeth of the output spur gear are sandwiched between the teeth of the two input spur gears." In other words, in the gear device 1, the action of "sandwiching the teeth of one spur gear between the teeth of two spur gears" cannot occur, as described in Patent Document 1.

[0033] (Second Embodiment) <1. Configuration of the gear apparatus according to the second embodiment> In the gear apparatus 1 according to the first embodiment described above, for example, the first spur gear 10A meshed with the corresponding second spur gears 20A to 20D in the order of first spur gear 10A → first spur gear 10B → first spur gear 10C → first spur gear 10D → first spur gear 10A....

[0034] In contrast, the gear apparatus 1 according to the second embodiment is configured such that, as shown in Figure 4, when the first multilayer spur gear 10 and the second multilayer spur gear 20 mesh and rotate, the 11th spur gear 10A and the 21st spur gear 20A mesh first, and then the 1n spur gear 10n and the 2n spur gear 20n mesh.

[0035] Specifically, in this embodiment, the 11th spur gear 10A and the 21st spur gear 20A mesh together, followed by the 13th spur gear 10C and the 23rd spur gear 20C. Next, the 12th spur gear 10B and the 22nd spur gear 20B mesh together, followed by the 14th spur gear 10D and the 24th spur gear 20D.

[0036] In the above, the first spur gear 10A is the 11th spur gear 10A, the first spur gear 10B is the 12th spur gear 10B, the first spur gear 10C is the 13th spur gear 10C, the first spur gear 10D is the 14th spur gear 10D, and the 13th spur gear 10C or the 14th spur gear 10D is the 1nth spur gear 10n.

[0037] Furthermore, the second spur gear 20A is the 21st spur gear 20A, the second spur gear 20B is the 22nd spur gear 20B, the second spur gear 20C is the 23rd spur gear 20C, the second spur gear 20D is the 24th spur gear 20D, and the 23rd spur gear 20C or the 24th spur gear 20D is the 2n spur gear 20n.

[0038] <2. Features of the gear apparatus according to the second embodiment> In a gear system, the heat generated by the collision during meshing (hereinafter referred to as "collision heat") is sequentially transferred to adjacent spur gears. That is, for example, the collision heat generated in the first spur gear 10A is transferred in the order of first spur gear 10B → first spur gear 10C → first spur gear 10D.

[0039] In this case, if the configuration is such that adjacent spur gears mesh sequentially, that is, in the order of first spur gear 10A → first spur gear 10B → first spur gear 10C → first spur gear 10D, then collision heat will also be generated in the order of first spur gear 10A → first spur gear 10B → first spur gear 10C → first spur gear 10D.

[0040] Therefore, in a configuration where adjacent spur gears mesh sequentially, the order of heat transfer due to collisions coincides with the order in which heat is generated due to collisions. As a result, as heat is transferred due to collisions, newly generated heat is added sequentially, causing the temperature of the gear mechanism 10 to gradually rise.

[0041] In contrast, in this embodiment, adjacent spur gears do not mesh sequentially, so the order of heat transfer at impact and the order of heat generation at impact do not coincide. Therefore, in this embodiment, the timing of heat transfer at impact and the timing of heat generation at impact are out of sync, which can suppress the temperature rise of the gear mechanism 10.

[0042] In Figure 4, the 11th spur gear 10A meshes with the 21st spur gear 20A, and then the 13th spur gear 10C meshes with the 23rd spur gear 20C. However, the 1n spur gear 10n is either the 13th spur gear 10C or the 14th spur gear 10D. Therefore, this embodiment may also have a configuration in which the 11th spur gear 10A meshes with the 21st spur gear 20A, and then the 14th spur gear 10D meshes with the 24th spur gear 20D.

[0043] Furthermore, when the first spur gear has five or more teeth, the definition of the first n spur gear 10n is the spur gear located on the opposite side of the 13th spur gear 10C from the 12th spur gear 10B, with the 13th spur gear 10C in between. Similarly, when the second spur gear has five or more teeth, the definition of the second n spur gear 20n is the spur gear located on the opposite side of the 23rd spur gear 20C from the 22nd spur gear 20B, with the 23rd spur gear 20C in between.

[0044] In the second embodiment, the same components and other elements as in the first embodiment are denoted by the same reference numerals. Therefore, redundant explanations are omitted in the second embodiment.

[0045] (Third embodiment) The gear apparatus according to the third embodiment, as shown in Figure 5, is configured such that there are multiple (five in this example) first spur gears 10A, 10B, 10C, 10D, and 10E arranged such that there are portions on the tooth tip trajectory line L3 that are convex in one direction of rotation. The tooth tip trajectory line L3 refers to an imaginary line connecting the centers of the tooth tips of each of the multiple first spur gears 10A to 10E.

[0046] As a result, compared to a gear system where the tooth tip trajectory line L3 is parallel to the first central axis L1, lubricating oil can be stored in the teeth of the multilayer spur gears 10 and 20. If the tooth tip trajectory line L3 is parallel to the first central axis L1, the lubricating oil will be easily discharged due to the rotation of the multilayer spur gears 10 and 20.

[0047] The second multilayer spur gear 20, which meshes with the first multilayer spur gear 10, has the same configuration as the first multilayer spur gear 10. Furthermore, the tooth tip trajectory line L3 may have multiple convex portions. In addition, if there are multiple convex portions, the direction of the first convex and the direction of the second convex may be opposite.

[0048] In the third embodiment, the same components and other elements as those in the first and second embodiments described above are denoted by the same reference numerals. Therefore, redundant explanations are omitted in the third embodiment.

[0049] (Other embodiments) In the embodiments described above, an example of a gear system according to the present disclosure was applied to a reduction gear. However, the present disclosure is not limited thereto. That is, the present disclosure can also be applied to, for example, a speed increaser or a rotational force transmission device.

[0050] In the embodiments described above, the multilayer spur gear was constructed with four or five spur gears. However, the disclosure is not limited thereto. That is, the disclosure may also describe a multilayer spur gear constructed with, for example, two or more spur gears.

[0051] Furthermore, this disclosure is not limited to the embodiments described above, but is sufficient to be consistent with the intent of the disclosures described in the embodiments described above. Therefore, it may be a configuration in which at least two of the embodiments described above are combined, or a configuration in which any of the illustrated components or components described with reference numerals in the embodiments described above are omitted.

Claims

1. A first multilayer spur gear (10) having at least four rows of first spur gear-shaped teeth (10A, 10B, 10C, 10D, 10E) arranged in a spur gear shape on a first central axis, wherein the teeth of adjacent first spur gear-shaped rows are offset from each other in the rotational direction, and the first multilayer spur gear has such rows of first spur gear-shaped teeth that they rotate as a single unit around the first central axis. A second multilayer spur gear (20) is provided, wherein a plurality of rows of second spur gear-shaped teeth (20A, 20B, 20C, 20D) are arranged in series on a second central axis parallel to the first central axis, and the teeth of adjacent rows of second spur gear-shaped teeth are offset from each other in the rotational direction, and the second multilayer spur gear comprises a second multilayer spur gear in which these rows of second spur gear-shaped teeth rotate as a single unit about the second central axis. The number of rows of teeth of the multiple first spur gears is equal to the number of rows of teeth of the multiple second spur gears. Each of the multiple rows of teeth of the first spur gear meshes with each of the corresponding rows of teeth of the second spur gear. Of the multiple rows of teeth of the first spur gear, the row of teeth of the first spur gear located on one end side of the first multilayer spur gear in the direction of the first central axis is designated as the 11th row of teeth, the row of teeth of the first spur gear adjacent to the 11th row of teeth is designated as the 12th row of teeth, the row of teeth of the first spur gear adjacent to the 12th row of teeth is designated as the 13th row of teeth, and the row of teeth of the first spur gear located on the opposite side of the 12th row of teeth, with the 13th row of teeth in between, is designated as the 14th row of teeth. When, among the plurality of rows of second spur gear-shaped teeth, the row of second spur gear-shaped teeth that meshes with the row of 11 spur gear-shaped teeth is designated as the 21st row of spur gear-shaped teeth, the row of second spur gear-shaped teeth that meshes with the row of 12 spur gear-shaped teeth is designated as the 22nd row of spur gear-shaped teeth, the row of second spur gear-shaped teeth that meshes with the row of 13 spur gear-shaped teeth is designated as the 23rd row of spur gear-shaped teeth, and the row of second spur gear-shaped teeth that meshes with the row of 14 spur gear-shaped teeth is designated as the 24th row of spur gear-shaped teeth, A gear apparatus characterized in that, when the first multilayer spur gear and the second multilayer spur gear mesh and rotate, the 11th row of spur gear teeth meshes with the 21st row of spur gear teeth, and then the 13th row of spur gear teeth meshes with the 23rd row of spur gear teeth.

2. When the imaginary line connecting the centers of the tooth tips of each of the multiple rows of the first spur gear-shaped teeth is defined as the tooth tip trajectory line, The gear device according to claim 1, wherein the tooth tip trajectory has at least one portion that is convex in one direction of rotation.

3. The gear apparatus according to claim 1 or 2, wherein when the first multilayer spur gear and the second multilayer spur gear mesh and rotate, the 13th row of spur gear teeth meshes with the 23rd row of spur gear teeth, then the 12th row of spur gear teeth meshes with the 22nd row of spur gear teeth, and then the 14th row of spur gear teeth meshes with the 24th row of spur gear teeth.

4. The gear apparatus according to claim 1 or 2, wherein when the first multilayer spur gear and the second multilayer spur gear mesh and rotate, the 13th row of spur gear teeth meshes with the 23rd row of spur gear teeth, then the 14th row of spur gear teeth meshes with the 24th row of spur gear teeth, and then the 12th row of spur gear teeth meshes with the 22nd row of spur gear teeth.

Images