Vehicle gear device

Abstract

The present disclosure relates to a gear device for a vehicle. Specifically, the present disclosure provides a gear device provided with a sliding contact portion provided on opposite sides of a holder of a planetary gear with the planetary gear interposed therebetween, and capable of making sliding contact with only a part of a side surface of the planetary gear.

Description

Technical Field

[0001] This disclosure relates to a gear mechanism for transmitting rotational force to the movable part of a vehicle seat. Background Technology

[0002] For example, in the planetary gear device described in Japanese Patent Application Publication No. 2022-88151, there is a sun gear, an internal gear, a planetary gear that meshes with the sun gear and the internal gear, and a support plate (also called a "retainer") that holds the planetary gear. An annular protrusion is provided on the inner circumference of the contact surface between the side of the planetary gear and the support plate. Summary of the Invention

[0003] If a thrust bearing is provided that slides in contact with the entire shaft end face region of the gear in order to limit the axial (also known as the "thrust direction") load and displacement acting on the gear, rotational resistance may sometimes increase. In view of this problem, this disclosure discloses an example of a gear mechanism capable of suppressing the increase in rotational resistance.

[0004] One aspect of this disclosure is a gear mechanism that transmits rotational force to a movable part of a vehicle seat, which preferably includes at least one of the following components.

[0005] That is, the constituent elements include: a sun gear, to which the driving force of the electric motor is input; a planetary gear, which rotates on its own axis while meshing with the sun gear, and revolves / rotates around the sun gear; a retainer, which supports the planetary gear to be able to rotate on its own axis and to be able to revolve around the sun gear, the retainer being configured to be coaxial with the rotational axis of the sun gear and rotatable; an internal gear, which meshes with the planetary gear; an output shaft, which receives rotational force from the retainer and rotates; and a sliding contact portion, which is disposed on the opposite side of the retainer with respect to the planetary gear, and the sliding contact portion is able to make sliding contact only with a portion of the side surface of the planetary gear, the sliding contact portion having an annular shape centered on the rotational axis of the sun gear.

[0006] Therefore, the sliding contact portion of this gear assembly functions as a thrust bearing that restricts the displacement of the planetary gear in the axial direction. Moreover, since the sliding contact portion can make sliding contact with only a part of the side surface of the planetary gear, this gear assembly can effectively reduce the rotational resistance of the planetary gear compared to a structure in which the sliding contact portion is in contact with the entire side surface of the planetary gear.

[0007] In addition, the gear device may have the following configuration, for example.

[0008] In other words, preferably, in the planetary gear, a boss protruding towards the sliding contact portion is provided on the opposite side of the retainer, and the central axis of the boss is aligned with the rotation center line of the planetary gear. Furthermore, it is preferable that the sliding contact portion can only make sliding contact with a portion of the front end face of the boss. Moreover, it is preferable that the sliding contact portion is composed of a protrusion facing the planetary gear.

[0009] Furthermore, it is preferable to provide a convex shaft portion on the retainer, which is inserted into a shaft hole located at the rotation center of the planetary gear. Moreover, it is preferable that the planetary gear is prevented from falling off the shaft portion while it is held by the retainer and the sliding contact portion.

[0010] Furthermore, the sliding contact portion is preferably configured to have at least a first protrusion and a second protrusion arranged concentrically. Moreover, the trajectory traced by the first protrusion across the rotation center of the planetary gear is preferably located on the opposite side of the second protrusion. This prevents significant tilting of the planetary gear's orientation in the gear mechanism.

[0011] Furthermore, the preferred gear assembly includes: a worm gear driven by an electric motor to rotate the worm gear; and a worm wheel meshing with the worm gear and coaxially configured with the sun gear, the worm wheel being connected to the sun gear, and preferably having a sliding contact portion disposed on the side of the worm wheel.

[0012] In this gear mechanism, the worm gear rotates in the opposite direction to the planetary gear. That is, when a virtual circle is drawn with the center of revolution (rotation), i.e. the rotation center of the sun gear, as the center, and passing through the rotation center of the planetary gear, the relative velocity of the planetary gear with respect to the sliding contact part differs significantly between the two sides separated by the virtual circle.

[0013] In this respect, since the sliding contact portion of the gear device can only make sliding contact with a portion of the side of the planetary gear, the rotational resistance of the planetary gear is reduced compared to a structure in which the entire side of the planetary gear makes sliding contact with the side of the worm gear. Attached Figure Description

[0014] Figure 1 This is a diagram showing the electric actuator of the first embodiment.

[0015] Figure 2 This is a diagram showing the structure of the gear device according to the first embodiment.

[0016] Figure 3 This is a diagram showing the structure of the gear device according to the first embodiment.

[0017] Figure 4 This is a diagram showing the structure of the gear device according to the first embodiment.

[0018] Figure 5 This is a diagram showing the structure of the gear device according to the first embodiment.

[0019] Figure 6 This is a diagram showing the structure of the gear device according to the first embodiment.

[0020] Figure 7 This is a diagram showing the worm gear of the first embodiment. Detailed Implementation

[0021] Exemplary embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0022] The embodiments described below are examples illustrating embodiments within the scope of this disclosure. That is, the technical solutions described in the claims are not limited to the specific structures or configurations shown in the following embodiments.

[0023] This embodiment is an example of applying the gear mechanism for vehicle seats (hereinafter referred to as "gear mechanism") disclosed herein to a seat (hereinafter referred to as "vehicle seat") installed in a vehicle or other means of transportation. Arrows and diagonal lines, etc., indicating direction in the various figures are figure elements indicated to facilitate understanding of the interrelationships of the figures and the shapes of components or parts.

[0024] The gear mechanism is not limited to the directions indicated in the accompanying drawings. The directions shown in the drawings are those with the vehicle of this embodiment assembled with the seat in the vehicle. Drawings marked with diagonal lines do not necessarily represent sectional views.

[0025] For any component or part that is marked with a symbol, at least one such component is provided, unless otherwise stated beforehand as "only one". That is, unless otherwise stated beforehand as "only one", at least two or more such components are provided. The gear device disclosed herein includes constituent elements such as components or parts marked with symbols, and at least one of the structural parts illustrated.

[0026] (First Embodiment)

[0027] <1. Overview of Gear Mechanisms>

[0028] The gear device in this embodiment is applied to Figure 1 The electric actuator 1 shown is an integrated structure that combines an electric motor 3 and a gear assembly 5. The electric motor 3 is the drive source that generates rotational force.

[0029] The gear device 5 in this embodiment constitutes a speed reduction device. Furthermore, the gear device 5 reduces the rotational force of the electric motor 3 and transmits it to the movable part of the vehicle seat. The movable part of the vehicle seat refers to, for example, a lifting linkage that moves the seat body up and down, or a tilting arm that moves the front end of the seat cushion up and down.

[0030] <2. General Structure of Gear Mechanism>

[0031] like Figure 2 As shown, the gear assembly 5 includes a gearbox 7 and a gear mechanism 10. The gearbox 7 is a housing that houses the gear mechanism 10. Additionally, the electric motor 3 is fixed to the gearbox 7 by bolts (not shown).

[0032] The gearbox 7 has at least a gearbox body 71 and a gearbox cover 72. The gearbox body 71 and the gearbox cover 72 are fastened to each other by a plurality of bolts (two in this embodiment) (not shown).

[0033] <2.1 Structure of Gear Mechanisms>

[0034] like Figure 3 As shown, the gear mechanism 10 includes at least a worm 11, a worm gear 12, and a planetary gear mechanism 13. The worm 11 is an externally threaded gear fixed to the output shaft (not shown) of the electric motor 3.

[0035] The worm gear 12 is a gear that meshes with and rotates with the worm 11. Furthermore, the worm gear 12 is positioned relative to the axis of rotation Lo (see reference) in the direction of its tooth line. Figure 2 It consists of inclined helical gears.

[0036] Planetary gear mechanism

[0037] like Figure 4 As shown, the planetary gear mechanism 13 includes at least a sun gear 14, planet gears 15, a retainer 16, and an internal gear 17 (see reference). Figure 3 The driving force of the electric motor 3 is input to the sun gear 14.

[0038] Specifically, the sun gear 14 is coaxially arranged with and connected to the worm gear 12. Therefore, the sun gear 14 and the worm gear 12 rotate as a unit.

[0039] In addition, such as Figure 5 As shown, a fitting portion 14A is provided on the sun gear 14 to engage with the worm gear 12. This fitting portion 14A is inserted into a fitting hole 12A provided on the worm gear 12 (see reference). Figure 7 ).

[0040] Furthermore, the worm gear 12 and the sun gear 14 are supported by the revolution shaft 19 so that they can rotate. The revolution shaft 19 is supported and fixed by the housing body 71. In addition, the fitting part 14A and the fitting hole 12A in this embodiment are configured in a gear shape (see reference). Figure 3 , Figure 6 ).

[0041] like Figures 3 to 5 As shown, the planetary gear 15 is a gear that rotates on its own axis while meshing with the sun gear 14, and revolves / rotates around the sun gear 14. In addition, in this embodiment, multiple (specifically, three) planetary gears 15 are provided.

[0042] All three planetary gears 15 have identical shapes. Therefore, when referred to simply as "planetary gear 15" in the following text, it can refer to both the three planetary gears 15 collectively and any single planetary gear 15.

[0043] The retainer 16 is a support that supports the planetary gear 15 for rotation and for revolution around the sun gear 14. The retainer 16 is configured to be coaxial with the rotational axis Lo of the sun gear 14 and is rotatable.

[0044] In addition, such as Figure 5 As shown, a shaft hole 15A is provided at the rotation center of the planetary gear 15. This shaft hole 15A is a through hole that passes through the planetary gear 15 along the rotation center axis L1. Furthermore, a convex shaft portion 16A is provided on the retainer 16 and is embedded in the shaft hole 15A.

[0045] Thus, planetary gear 15 can rotate on its own axis L1 while simultaneously revolving / rotating around the rotational axis Lo of sun gear 14. An output shaft 18 (see reference) is provided on the retainer 16. Figure 4 Thus, the output shaft 18 can obtain rotational force from the retainer 16 and rotate.

[0046] like Figure 3 As shown, the internal gear 17 is a ring-shaped gear that meshes with the planetary gear 15. Furthermore, in this embodiment, the internal gear 17 is integrally formed with the inner wall of the cover 72, and constitutes an integral part of the cover 72.

[0047] <Support Structure of Planetary Gears>

[0048] like Figure 6As shown, a sliding contact portion 20 is provided on the opposite side of the retainer 16, separated from the planetary gear 15. The sliding contact portion 20 is a part that can make sliding contact only with a portion of the side surface of the planetary gear 15. This sliding contact portion 20 is configured as an annular shape centered on the rotational axis Lo of the sun gear 14 (see reference). Figure 7 ).

[0049] That is to say, in planetary gear 15, on the opposite side of retainer 16 ( Figure 6 A boss 15B is provided on the lower side of the planetary gear 15. The boss 15B faces the sliding contact portion 20. Figure 6 The lower part (in the middle) has a cylindrical protrusion. In addition, the central axis of this protrusion 15B is aligned with the rotational central axis L1 of the planetary gear 15.

[0050] The sliding contact 20 can only contact the front end face 15C of the boss 15B (in Figure 6 The sliding contact portion 20 of the planetary gear 15B is partially slidably contacted. Furthermore, the sliding contact portion 20 of this embodiment is composed of a protrusion that protrudes toward the planetary gear 15.

[0051] Specifically, the sliding contact portion 20 is configured to have at least a first protrusion 21 and a second protrusion 22 arranged concentrically (see reference). Figure 7 Furthermore, the trajectory traced by the first protrusion 21 across the rotation center of the planetary gear 15 is located on the opposite side of the second protrusion 22.

[0052] Furthermore, "the trajectory depicted by the rotation center of planetary gear 15" refers to a circle centered on the rotation center of sun gear 14 and passing through the rotation center of planetary gear 15. Moreover, the first protrusion 21 is located inside the circle, and the second protrusion 22 is located outside the circle.

[0053] Moreover, such as Figure 6 As shown, with the planetary gear 15 held by the retainer 16 and the sliding engagement portion 20, the possibility of the planetary gear 15 dislodging from the shaft portion 16A of the retainer 16 is limited. Furthermore, as... Figure 7 As shown, in this embodiment, the sliding joint 20 is provided on the side of the worm gear 12.

[0054] <3. Features of the gear device in this embodiment>

[0055] A sliding contact portion 20 is provided on the opposite side of the retainer 16, separated from the planetary gear 15, capable of sliding contact only with a portion of the side surface of the planetary gear 15. Thus, the sliding contact portion 20 of the gear assembly 5 functions as a thrust bearing, which restricts the displacement of the planetary gear 15 in the axial direction.

[0056] Furthermore, since the sliding contact portion 20 can only make sliding contact with a portion of the side surface of the planetary gear 15, compared to a structure in which the sliding contact portion 20 makes contact with the entire side surface of the planetary gear 15, the gear device 5 can reduce the rotational resistance of the planetary gear 15.

[0057] Furthermore, if a structure is adopted in which the sliding contact portion 20 is in integral contact with the side surface of the planetary gear 15, the area of ​​the sliding contact surface of the sliding contact portion 20 will inevitably increase. In addition, in this embodiment, the worm gear 12 including the sliding contact portion 20 is made of resin manufactured by injection molding.

[0058] Furthermore, it is difficult to ensure high flatness when forming a sliding contact surface with a large area by resin molding. In addition, since the ejector pin of the injection molding machine must be set at a position corresponding to the side of the worm gear 12, it is difficult to form a sliding contact surface with a large area by resin molding.

[0059] In this embodiment, since the sliding contact portion 20 only makes sliding contact with a portion of the side surface of the planetary gear 15, the sliding contact surface can be reduced. This improves both the freedom of the ejector pin's placement and the flatness of the sliding contact surface.

[0060] Furthermore, in the first protrusion 21 and the second protrusion 22 constituting the sliding contact portion 20, the trajectory drawn by the first protrusion 21 across the rotation center of the planetary gear 15 is located on the opposite side of the second protrusion 22.

[0061] Therefore, in this gear device 5, not only can the sliding contact surfaces of the first protrusion 21 and the second protrusion 22 be reduced, but even if the sliding contact surfaces are reduced, the large tilting of the planetary gear 15 can be suppressed.

[0062] Furthermore, in this embodiment, the sliding contact portion 20 is provided on the side of the worm gear 12. Moreover, the rotation direction of the worm gear 12 is opposite to the rotation direction of the planetary gear 15.

[0063] Therefore, when a virtual circle is defined with the center of revolution as the center and passing through the rotation center of the planetary gear 15, the relative speed of the planetary gear 15 with respect to the sliding contact portion 20 is significantly different between the two sides separated by the virtual circle.

[0064] In this regard, since the sliding contact portion 20 of the gear device 5 can only make sliding contact with a portion of the side of the planetary gear 15, the rotational resistance of the planetary gear 15 is reduced compared to the structure in which the entire side of the planetary gear 15 makes sliding contact with the side of the worm gear 12.

[0065] (Other implementation methods)

[0066] In the above embodiment, the internal gear 17 is integrally formed with the inner wall of the cover 72. However, this disclosure is not limited to this. That is, the disclosure can be configured such that, for example, the internal gear 17 is made of a different material than the cover 72.

[0067] The sliding contact portion 20 in the above embodiment is composed of a protrusion extending toward the planetary gear 15. However, this disclosure is not limited to this. That is, this disclosure may also have the following configuration, for example.

[0068] That is, this disclosure can be configured as "a structure in which an annular groove is provided on the side of the worm gear 12, and the opening edge of the groove serves as a sliding contact part 20", or "a structure in which a simple plane is used as the sliding contact part 20, and a protrusion is provided on the boss part 15B to slide in contact with the sliding contact part 20, or a groove is provided on the front end face 15C of the boss part 15B".

[0069] The sliding joint 20 in the above embodiment is configured to have a first protrusion 21 and a second protrusion 22. However, this disclosure is not limited thereto. That is, the disclosure may, for example, be configured such that the sliding joint 20 consists of only a single protrusion.

[0070] In the above embodiment, the sliding contact portion 20 is configured to make sliding contact only with a portion of the front end portion 15C of the boss portion 15B. However, this disclosure is not limited to this. That is, the disclosure may also be configured such that the sliding contact portion 20 makes sliding contact with portions other than the boss portion 15B.

[0071] In the above embodiment, the sliding engagement portion 20 is provided on the side of the worm gear 12. However, this disclosure is not limited thereto.

[0072] In the above embodiments, the vehicle seat of this disclosure is applied to a vehicle. However, the application of the invention disclosed in this specification is not limited thereto. That is, this disclosure can also be applied to seats used in vehicles such as railway vehicles, ships, and aircraft, as well as fixed seats used in theaters or homes.

[0073] Furthermore, this disclosure is not limited to the embodiments described above, as long as it conforms to the spirit of the disclosure. Therefore, this disclosure may be, for example, a combination of at least two of the above-described embodiments, or it may be a configuration that eliminates any of the constituent elements illustrated or described by reference numerals in the above embodiments.

Claims

1. A gear mechanism that transmits rotational force to a movable part of a vehicle seat, characterized in that it comprises: The sun gear is into which the driving force of the electric motor is input; Planetary gears, which rotate on their own axis while meshing with the sun gear, and revolve / rotate around the sun gear. A retainer that supports the planetary gears for rotation and for revolution around the sun gear, the retainer being configured to be coaxial with the rotational axis of the sun gear and rotatable; An internal gear that meshes with the planetary gear; An output shaft that rotates by receiving rotational force from the retainer; as well as A sliding contact portion is disposed on the opposite side of the retainer, separated from the planetary gear, and the sliding contact portion is capable of sliding contact only with a portion of the side surface of the planetary gear, the sliding contact portion having an annular shape centered on the rotational center axis of the sun gear.

2. The gear device according to claim 1, characterized in that, In the planetary gear, a boss protruding towards the sliding contact portion is provided on the opposite side of the retainer, and the central axis of the boss is aligned with the rotation center line of the planetary gear. Furthermore, the sliding contact portion is capable of making sliding contact only with a portion of the front end face of the boss portion.

3. The gear device according to claim 2, characterized in that, The sliding contact portion is composed of protrusions facing the planetary gear.

4. The gear device according to claim 3, characterized in that, The retainer has a convex shaft portion that is fitted into a shaft hole located at the rotation center of the planetary gear. Furthermore, the planetary gear is restricted from detaching from the shaft while it is held by the retainer and the sliding contact.

5. The gear device according to claim 4, characterized in that, The sliding contact portion is configured to have at least a first protrusion and a second protrusion arranged concentrically. Furthermore, the trajectory traced by the first protrusion across the rotation center of the planetary gear is located on the opposite side of the second protrusion.

6. The gear device according to any one of claims 1 to 5, characterized in that, It also has: The worm gear, driven by the electric motor to rotate; and A worm gear, which meshes with the worm and is coaxially arranged with the sun gear, is connected to the sun gear. The sliding contact portion is disposed on the side of the worm gear.

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