Gear device

Abstract

To provide a gear device that can restrain the occurrence of unusual noise and extend its life.SOLUTION: A gear device 100 comprises: a first shaft member 111; an eccentric member 120 comprising a cylindrical surface eccentric with respect to a shaft core of the first shaft member 111, and to be rotated together with the first shaft member; a bearing 130 arranged on an outer periphery of the eccentric member 120; a first gear 140 comprising an external tooth part 141 arranged on an outer periphery of the bearing 130, an internal tooth part 142 provided with a plurality of internal teeth in a circumferential direction at a position side by side with the external tooth part 141 in an axial direction, and a main body part 143 connecting the external tooth part 141 and the internal tooth part 142; a fixed gear 150 comprising a plurality of internal teeth engaged with external teeth of the first gear 140 in a first region 241; and a second gear 160 comprising a plurality of external teeth engaged with the internal teeth of the first gear in a second region 242. The main body part 143 of the first gear 140 comprises a circulation passage 145 for circulating a lubricant between the first region 241 and the second region 242.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gear device that functions as a speed reducer or a speed increaser. [Background technology]

[0002] Conventionally, there are reducers that are equipped with multiple gears to reduce the input rotation angle and output it. For example, Patent Document 1 describes a reducer that reduces the rotation angle by eccentrically rotating an external gear with fewer teeth than the internal gear around the internal gear. Rotation transmission parts such as bearings and gears equipped in the reducer are lubricated with oil, grease, and other lubricants to reduce friction, suppress the generation of abnormal noise, and improve durability. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-113598 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as rotational transmission parts continue to operate, lubricants such as oil and grease can accumulate in specific areas of the rotational transmission parts other than the contact points, preventing an adequate supply of lubricant to the meshing parts of the gears, resulting in issues such as abnormal noise and reduced durability.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a gear device that can continuously supply lubricant such as oil or grease to the meshing parts of the gears by stirring and circulating the lubricant, thereby preventing the lubricant from stagnating. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, one gear device of the present invention comprises a first shaft member, an eccentric member having a cylindrical surface eccentric with respect to an axis of the first shaft member and rotating together with the first shaft member, a bearing arranged on the outer periphery of the eccentric member, a first gear having an external tooth portion arranged on the outer periphery of the bearing and having a plurality of external teeth provided in the circumferential direction, an internal tooth portion having a plurality of internal teeth provided in the circumferential direction at a position aligned with the external tooth portion in the axial direction, and a main body portion connecting the external tooth portion and the internal tooth portion, a fixed gear having a plurality of internal teeth that mesh with the external teeth of the first gear in a first region, and a second gear having a plurality of external teeth that mesh with the internal teeth of the first gear in a second region, and the main body portion of the first gear is provided with a flow passage for circulating lubricant between the first region and the second region. Effect of the Invention

[0007] According to the present invention, the lubricant can be moved from the fixed gear side to the second gear side by meshing between the fixed gear and the external teeth of the first gear, and the lubricant can be moved from the second gear side to the fixed gear side by meshing between the internal teeth of the first gear and the second gear, and the lubricant can be circulated to continuously supply lubricant to the meshing parts of the gears. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an outline of the configuration of a gear device according to an embodiment. [Diagram 2] FIG. 4 is a perspective view showing the first gear from the second gear side. [Diagram 3] FIG. 4 is a perspective view showing the first gear from the fixed gear side. [Figure 4] FIG. 11 is a perspective view showing a first gear of Modified Example 1 from a second gear side. [Diagram 5] FIG. 11 is a cross-sectional view showing the outline of the configuration of a gear device according to a first modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of a gear device according to the present invention will be described with reference to the drawings. Note that the following embodiment is an example for explaining the present invention, and is not intended to limit the present invention. For example, the shapes, structures, materials, components, relative positional relationships, connection states, numerical values, mathematical expressions, contents of each step in the method, and the order of each step shown in the following embodiment are examples, and may include contents not described below. In addition, geometric expressions such as parallel and orthogonal may be used, but these expressions do not indicate mathematical strictness, and include substantially permissible errors, deviations, etc. In addition, expressions such as simultaneous and identical also include substantially permissible ranges.

[0010] In addition, the drawings are schematic diagrams in which emphasis, omission, or adjustment of the ratio is appropriately performed in order to explain the present invention, and differ from the actual shapes, positional relationships, and ratios. In addition, the X-axis, Y-axis, and Z-axis that may be shown in the drawings indicate orthogonal coordinates that are arbitrarily set for the explanation of the drawings. In other words, the Z-axis is not necessarily an axis along the vertical direction, and the X-axis and Y-axis are not necessarily present in a horizontal plane.

[0011] In addition, in the following, a plurality of inventions may be collectively described as one embodiment, and some of the contents described below are described as optional components related to the present invention.

[0012] FIG. 1 is a cross-sectional view showing an outline of the configuration of a gear device 100 according to an embodiment. Note that in FIG. 1, the teeth of the gears are omitted. The gear device 100 includes a first shaft member 111, an eccentric member 120, a bearing 130, a first gear 140, a fixed gear 150, and a second gear 160. In the present embodiment, the gear device 100 includes a second shaft member 112 and a housing 170. Note that the shape of the teeth of each gear is not particularly limited, and examples of the shape include an involute tooth profile, a cycloid tooth profile, and a tooth profile that is a combination of these. When the first shaft member 111 is an input shaft member and the second shaft member 112 is an output shaft member, the gear device 100 functions as a reducer, and when the first shaft member 111 is an output shaft member and the second shaft member 112 is an input shaft member, the gear device 100 functions as a speed increaser. In this embodiment, the first shaft member 111 will be described as an input shaft member, and the second shaft member 112 will be described as an output shaft member. The use of the gear device 100 is not particularly limited, but it can be used, for example, for power assist in a steering device equipped in a moving body such as an automobile, or for steering drive that generates a force for steering the steered wheels of a moving body.

[0013] The first shaft member 111 is a shaft-shaped structural member that is connected to, for example, an output shaft of a motor, and to which torque is input around an axis 211 of the first shaft member 111. In the case of this embodiment, the first shaft member 111 is a cylindrical member, and is attached to the housing 170 via a second bearing 172 so as to be rotatable around the axis 211.

[0014] The eccentric member 120 has a cylindrical surface on its outer periphery that is eccentric with respect to the axis 211 of the first shaft member 111, and is a member that rotates together with the first shaft member 111. The outer periphery of the eccentric member 120 is circular when viewed from the direction of the axis 211, and the central axis 220 is disposed at a position eccentric with respect to the axis 211. In the case of this embodiment, the eccentric member 120 is molded integrally with the first shaft member 111. Note that the eccentric member 120 and the first shaft member 111 are separate bodies, and may be joined by press fitting or the like.

[0015] The bearing 130 is a member attached to the outer periphery of the eccentric member 120, and holds the first gear 140 rotatably relative to the eccentric member 120. The type, shape, and number of the bearings 130 are not particularly limited. The bearing 130 may be a ball bearing with a spherical rolling element 131, or a roller bearing with a cylindrical rolling element 131. In the present embodiment, the bearing 130 includes a spherical rolling element 131, and the length of the outer race 132 of the bearing 130 is longer than the length of the inner race 133 in the axial direction (X-axis direction in the drawing). The bearing 130 includes only one rolling element 131 in the axial direction. That is, the bearing 130 does not include rolling elements 131 aligned in the axial direction. The bearing 130 may include a plurality of rolling elements 131 aligned in the axial direction. The bearing 130 may also include a plurality of bearings 130 aligned in the axial direction.

[0016] FIG. 2 is a perspective view of the first gear 140 from the second gear 160 side. FIG. 3 is a perspective view of the first gear 140 from the fixed gear 150 side. The first gear 140 is attached to the outer periphery of the outer race 132 of the bearing 130, and has an external teeth portion 141 on which a plurality of external teeth are provided in the circumferential direction. The material of the first gear 140 is not limited, and examples thereof include resin and metal. The first gear 140 revolves together with the eccentric member 120 as the first shaft member 111 rotates. The first gear 140 is rotatably attached to the eccentric member 120 by the bearing 130. The shape of the first gear 140 is not limited. In addition, the first gear 140 includes an internal teeth portion 142 on which internal teeth are provided, which is aligned with the external teeth portion 141 and the second shaft member 112 side (X-side in the figure) in the axial direction (X-axis direction in the figure). The external teeth portion 141 and the internal teeth portion 142 are cylindrical, and are disposed at a position eccentric to the axis 211 so as to coincide with the central axis 220 of the eccentric member 120. The internal teeth portion 142 has a larger diameter than the external teeth portion 141. The external teeth portion 141 and the internal teeth portion 142 are connected via a cylindrical main body portion 143. The main body portion 143 will be described in detail later.

[0017] The fixed gear 150 is a gear having a plurality of internal teeth that mesh with the external teeth of the first gear 140 in a first region 241. The fixed gear 150 is cylindrical, and the axis of the fixed gear 150 coincides with an axis 211 that is the rotation axis of the first shaft member 111. The fixed gear 150 has a larger outer diameter than the external teeth portion 141 of the first gear 140, and the number of internal teeth of the fixed gear 150 is greater than the number of teeth of the external teeth portion 141. The first gear 140 revolves around the axis 211 while meshing with the fixed gear 150 in the first region 241. In other words, the first gear 140 can be expressed as an internally-engraved planetary gear with the fixed gear 150 as a ring gear.

[0018] There is no limitation on the material of the fixed gear 150. In the present embodiment, the fixed gear 150 is made of metal. The fixed gear 150 is fixedly attached to the inner circumferential surface of the housing 170.

[0019] The second gear 160 is a gear having a plurality of external teeth that mesh with the internal teeth of the first gear 140 in the second region 242. The second gear 160 has an inner diameter smaller than the internally toothed portion 142 of the first gear 140, and the number of external teeth of the second gear 160 is smaller than the number of teeth of the internally toothed portion 142. The material of the second gear 160 is not limited. In this embodiment, the second gear 160 is made of metal. The axis of the second gear 160 coincides with the axis 211 of the first shaft member 111.

[0020] The internal teeth of the first gear 140 revolve around the shaft core 211 while rotating around the central axis 220. The internal teeth portion 142 of the first gear 140 functions as a ring gear and meshes with the internal teeth of the first gear 140 in a second region 242. The second gear 160 functions as a planetary gear and rotates around the shaft core 211 due to the rotation and revolution of the internal teeth portion 142.

[0021] The second shaft member 112 is a shaft-shaped structural member that rotates around the axis 211 together with the second gear 160 and outputs torque around the axis 211 to the outside. In the case of this embodiment, the first shaft member 111 is a cylindrical member, and is attached to the housing 170 via a third bearing 173 so as to be rotatable around the axis 211. In the case of this embodiment, the second shaft member 112 is molded integrally with the second gear 160. Note that the second gear 160 and the second shaft member 112 are separate bodies, and may be joined by press-fitting or the like.

[0022] The main body 143 of the first gear 140 includes a flow passage 145 for circulating the lubricant between the first region 241 and the second region 242. The arrows in the flow passage 145 in FIG. 1 indicate the flow of the lubricant. In this embodiment, the flow passage 145 is a hole penetrating from the end face on the outer teeth side (the fixed gear 150 side) of the cylindrical main body 143 to the end face on the inner teeth side (the second gear 160 side). The flow passage 145 extends in a direction intersecting with the axial direction. The cross-sectional shape of the flow passage 145 taken along a plane perpendicular to the axial direction is not limited, and examples of the shape include a circle, an oval, an ellipse, and a rectangle. In this embodiment, the cross-sectional shape of the flow passage 145 is a sector shape centered on the central axis 220. The flow passages 145 are arranged in a row intermittently in the circumferential direction of the cylindrical main body 143. The number of flow passages 145 provided in main body 143 and the size of each passage are determined comprehensively based on the structural strength of first gear 140, the degree of circulation of the lubricant, and the like.

[0023] The present invention is not limited to the above-described embodiment. For example, the components described in this specification may be combined in any manner, or some of the components may be removed to create another embodiment of the present invention. In addition, the present invention also includes modifications that are made to the above-described embodiment by those skilled in the art without departing from the spirit of the present invention, i.e., the meaning of the words in the claims.

[0024] 4 and 5, the flow passage 145 may be in the form of a groove extending in the axial direction and recessed in the radial direction from the inner peripheral surface of the main body 143. The groove-shaped flow passage 145 opens at the end face of the main body 143 on the outer teeth side and also opens at the end face on the inner teeth side, and the opening of the flow passage 145 facing the inside is sealed by the outer race 132 of the bearing 130. In this way, the groove-shaped flow passage 145 allows the lubricant to circulate between the first region 241 and the second region 242.

[0025] In addition, the external teeth portion 141, the main body portion 143, and the internal teeth portion 142 of the first gear 140 may be integrally formed from resin or the like, or the external teeth portion 141, the main body portion 143, and the internal teeth portion 142 may be formed separately and then joined together.

[0026] Furthermore, the flow passages 145 may extend parallel to the axial direction. Furthermore, the phase of the opening of the flow passages 145 on the outer teeth side of the main body 143 and the opening on the inner teeth side do not have to match. In other words, the flow passages 145 may extend inclined in the circumferential direction of the main body 143.

[0027] As described above, the gear device 100 of the first aspect according to the present embodiment includes the first shaft member 111, the eccentric member 120 having a cylindrical surface eccentric with respect to the axis of the first shaft member 111 and rotating together with the first shaft member, the bearing 130 arranged on the outer periphery of the eccentric member 120, the external teeth portion 141 arranged on the outer periphery of the bearing 130 and having a plurality of external teeth provided in the circumferential direction, and the internal teeth portion 141 arranged in the axial direction and having a plurality of internal teeth provided in the circumferential direction at a position aligned with the external teeth portion 141. the first gear 140 having an external tooth portion 142 and a main body portion 143 connecting the external tooth portion 141 and the internal tooth portion 142; a fixed gear 150 having a plurality of internal teeth that mesh with the external teeth of the first gear 140 in a first region 241; and a second gear 160 having a plurality of external teeth that mesh with the internal teeth of the first gear in a second region 242, wherein the main body portion 143 of the first gear 140 has a flow passage 145 that allows the lubricant to flow between the first region 241 and the second region 242.

[0028] According to the first gear 140 of the first embodiment, the following state is achieved by operating the gear device. That is, the lubricant pushed out and flowing due to the meshing of the fixed gear 150 and the external teeth of the first gear 140 moves from the first region 241 to the second region 242 through the flow passage 145 close to the meshing portion between the fixed gear 150 and the external teeth of the first gear 140. On the other hand, the lubricant pushed out and flowing due to the meshing of the second gear 160 and the internal teeth of the first gear 140 moves from the second region 242 to the first region 241 through the flow passage 145 close to the meshing portion between the second gear 160 and the internal teeth of the first gear 140. The meshing portion between the fixed gear 150 and the external teeth of the first gear 140 and the meshing portion between the second gear 160 and the internal teeth of the first gear 140 are out of phase with each other (180 degrees out of phase in the present embodiment). Furthermore, the meshing portion between the fixed gear 150 and the external teeth of the first gear 140, and the meshing portion between the second gear 160 and the internal teeth of the first gear 140 rotate (revolve) around the axis 211. As a result, the lubricant is stirred and circulated. This makes it possible to prevent the lubricant from accumulating in one area and not being supplied to the meshing portion, thereby improving lubrication, suppressing the generation of abnormal noise, and improving the durability of the gear device 100.

[0029] Furthermore, by providing the flow passage 145, the weight of the first gear 140 can be reduced, which can contribute to reducing the weight of the entire gear device 100. [Industrial Applicability]

[0030] The present invention is useful, for example, as a gear device mounted on a moving body such as an automobile or an industrial machine. [Explanation of symbols]

[0031] 100... gear device, 111... first shaft member, 112... second shaft member, 120... eccentric member, 130... bearing, 131... rolling element, 132... outer race, 133... inner race, 140... first gear, 141... external teeth portion, 142... internal teeth portion, 143... main body portion, 145... flow passage, 150... fixed gear, 160... second gear, 170... housing, 172... second bearing, 173... third bearing, 211... shaft core, 220... central shaft, 241... first region, 242... second region

Claims

[Claim 1] A first shaft member; an eccentric member having a cylindrical surface eccentric with respect to an axis of the first shaft member and rotating together with the first shaft member; a bearing disposed on an outer periphery of the eccentric member; a first gear including: an external tooth portion disposed on an outer periphery of the bearing and having a plurality of external teeth provided in a circumferential direction; an internal tooth portion having a plurality of internal teeth provided in a circumferential direction at a position aligned with the external tooth portion in an axial direction; and a main body portion connecting the external tooth portion and the internal tooth portion; a fixed gear having a plurality of internal teeth that mesh with the external teeth of the first gear in a first region; a second gear having a plurality of external teeth that mesh with the internal teeth of the first gear in a second region, The main body of the first gear includes a flow passage for allowing a lubricant to flow between the first region and the second region. Gear mechanism.

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