gear mechanism

Abstract

To improve the durability of a housing and a stopper plate.SOLUTION: A gear device includes a first gear, a second gear to be eccentric along with the rotation of the first gear, and a third gear to be rotated at a speed lower than the rotating speed of the first gear along with the eccentricity of the second gear, and further includes a stopper plate 63 for engaging with the second gear in rugged relation to restrict the rotating movement of the second gear while allowing the linear movement thereof, and a housing 36 for storing the stopper plate 63 in the state of restricting the rotating movement of the stopper plate 63 while allowing the linear movement thereof, the stopper plate 63 having an arm part 63b extending along the direction of the linear movement of the topper plate 63, the housing 36 having a storage chamber 36a for storing the arm part 63b, the arm part 63b having a branch portion 63e branching into two or more parties, the storage chamber 36a having a projecting wall arranged on the branch portion 63e.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a gear device. [Background technology]

[0002] Patent Document 1 describes a gear device used in a seat lifter device. As shown in FIG. 14 , the gear device 70 includes a worm gear (worm wheel) 71 mounted on an eccentric shaft 74 to form a first gear 75, and an external gear 72 serving as a second gear that becomes eccentric as the worm gear (worm wheel) 71 rotates. The gear device 70 also includes an internal gear 73 serving as a third gear that rotates at a speed slower than the rotational speed of the worm gear (worm wheel) 71 as the external gear 72 becomes eccentric. The gear device 70 includes a stopper plate 76 that restricts rotational movement while allowing linear movement of the external gear 72. The external gear 72 has a pair of engaging claws 72a protruding along the thickness direction. The stopper plate 76 has a pair of recesses 76a that engage with the engaging claws 72a. The engaging claws 72a of the external gear 72 engage with the recesses 76a of the stopper plate 76, thereby restricting rotational movement of the external gear 72 while allowing linear movement.

[0003] The gear device 70 includes a housing 77 that houses the stopper plate 76 in a state where linear movement of the stopper plate 76 is permitted but rotational movement is restricted. A cover 78 is attached to the housing 77, with a worm gear (worm wheel) 71, an external gear 72, and an internal gear 73 also housed therein. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-99085 Summary of the Invention [Problem to be solved by the invention]

[0005] 14, in the gear device 70 of Patent Document 1 and the like, the rotational movement of the stopper plate 76 is restricted by the housing 77, which tends to increase the load on both the housing 77 and the stopper plate 76. Therefore, improving the durability of the housing 77 and the stopper plate 76 is an issue to be addressed. [Means for solving the problem]

[0006] A gear device for solving the above problem is a gear device comprising a first gear, a second gear that becomes eccentric as the first gear rotates, and a third gear that rotates at a speed slower than the rotational speed of the first gear as the second gear becomes eccentric, and further comprising: a stopper plate that engages with the second gear in a concave-convex relationship, thereby allowing linear movement of the second gear while restricting rotational movement; and a housing that accommodates the stopper plate in a state in which the stopper plate allows linear movement while restricting rotational movement, wherein the stopper plate has an arm that extends in the direction of linear movement of the stopper plate, and the housing has a storage chamber that accommodates the arm, the arm has a branch portion that branches into two or more branches, and the storage chamber has a convex wall that is arranged at the branch portion.

[0007] With this configuration, when a force is applied to rotate the stopper plate, the force can be received not only by the housing chamber but also by the convex wall. The force applied from the arm portion can be dispersed and received, improving the durability of the housing and the stopper plate.

[0008] In the gear device, the accommodation chamber of the housing preferably has a guide portion that guides the arm portion of the stopper plate when the arm portion is accommodated in the accommodation chamber. With this configuration, the arm portion can be accommodated while being guided, making it easier to accommodate the arm portion in the accommodation chamber.

[0009] In the gear device, the guide portion is preferably provided on the convex wall. With this configuration, even if the accommodation chamber has a convex portion, it is easy to accommodate the arm portion. In the gear device, it is preferable that the accommodation chamber has a peripheral wall, and the guide portion is provided on the peripheral wall. With this configuration, the peripheral wall can be effectively used as the guide portion.

[0010] In the above gear device, it is preferable that the convex wall has a first convex wall extending continuously from the peripheral wall and a second convex wall extending continuously from the first convex wall toward the branched portion of the arm, and that the protruding height of the first convex wall is greater than the protruding height of the second convex wall and greater than the thickness of the arm. With this configuration, when the arm is accommodated in the accommodation chamber, even if the position of the arm is slightly misaligned with respect to the accommodation chamber, the arm can be easily guided to the correct position by preferentially abutting against the first convex wall. [Effects of the Invention]

[0011] According to the gear device of the present invention, the durability of the housing and the stopper plate can be improved. [Brief explanation of the drawings]

[0012] [Figure 1] Side view of the seat. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] A close-up view of the housing's chamber. [Figure 8] FIG. 10 is an enlarged view of an accommodation chamber of the housing that accommodates the arm portion of the stopper plate. [Figure 9] FIG. [Figure 10]FIG. 10 is a plan view of the stopper plate and the second gear. [Figure 11] FIG. 4 is a perspective view of the rear side of the second gear. [Figure 12] Side view of second gear. [Figure 13] FIG. [Figure 14] FIG. 1 is an exploded perspective view of a prior art gear device. DETAILED DESCRIPTION OF THE INVENTION

[0013] The gear device 32 will be described with reference to FIGS. (About the seat lifter device) FIG. 1 shows a side view of a seat 11. The seat 11 is mounted on a vehicle such as a four-wheeled automobile. A slide rail 12 is arranged on a floor 1 of the vehicle. The slide rail 12 has a pair of upper rails 21 and a pair of lower rails 22. The lower rails 22 are attached to the floor 1 of the vehicle. The upper rails 21 are attached to the lower rails 22 so as to be slidable in the fore-and-aft direction of the vehicle.

[0014] Brackets 23 are attached to the front and rear end sides of the pair of upper rails 21, respectively. A front link 26 is attached to the bracket 23 on the front end side by a pin 24. A rear link 27 is attached to the bracket 23 on the rear end side by the pin 24. In other words, the pair of front links 26 and the pair of rear links 27 are attached to the pair of upper rails 21 via the brackets 23. The front link 26 and the rear link 27 are attached rotatably with respect to the bracket 23.

[0015] The cushion frame 25 is attached to the ends of the front link 26 and the rear link 27 opposite to the end attached to the bracket 23 by a rod 28. The front link 26 and the rear link 27 are attached to the cushion frame 25 so as to be rotatable.

[0016] The bracket 23, the front link 26, the rear link 27, and the cushion frame 25 are attached as described above to form a so-called four-joint rotation mechanism.

[0017] A gear 27a is provided on one of the pair of rear links 27. The gear 27a has a plurality of teeth arranged in a substantially arc shape with the rod 28 as the center. A drive unit 29 is attached to the cushion frame 25. The drive unit 29 has a pinion 29a. The pinion 29a meshes with the teeth of the gear 27a of the rear link 27. When the drive unit 29 is driven, the pinion 29a rotates. As the pinion 29a rotates, the position of the pinion 29a relative to the gear 27a changes, and the distance between the pin 24 that secures the rear link 27 and the pinion 29a changes. When the distance between the pin 24 that secures the rear link 27 and the pinion 29a changes, the rear link 27 can be rotated around the pin 24 as the center of rotation by the action of the four-bar rotation mechanism. This allows the cushion frame 25 to be raised and lowered relative to the bracket 23.

[0018] The seat lifter device is configured by the bracket 23, the front link 26, the rear link 27, the cushion frame 25, and the drive device 29. The drive device 29 may be referred to as a gearbox motor.

[0019] (Regarding drive unit 29) As shown in Figures 2 and 3, the drive device 29 includes a motor 31 and a gear device 32. The gear device 32 reduces the rotation speed of the motor 31 to rotate the pinion 29a. Therefore, the gear device 32 can be referred to as a reduction gear. Note that in Figure 2, the multiple teeth of the pinion 29a are omitted. Similarly, teeth of gears, etc. are omitted in the subsequent figures.

[0020] 3, the motor 31 has a case 31a and components housed in the case 31a. The components include, for example, a motor shaft, a stator, a rotor, a coil, and a magnet (all of which are not shown). The motor 31 is driven by electric power and rotates the motor shaft about a rotation axis Ax1.

[0021] (Regarding gear device 32) As shown in FIGS. 3 and 4, the gear device 32 includes a rotation transmission mechanism 35, a cylindrical housing 36 with a bottom, and a cover 37.

[0022] The rotation transmission mechanism 35 is accommodated in a housing 36. The rotation transmission mechanism 35 has a first reduction gear unit 41 serving as a speed reduction mechanism, a second reduction gear unit 42 also serving as a speed reduction mechanism, and an output shaft 43. The driving force of the motor 31 is transmitted to the second reduction gear unit 42 via the first reduction gear unit 41, and further transmitted from the second reduction gear unit 42 to the output shaft 43.

[0023] The output shaft 43 is supported by the housing 36 and the cover 37 so as to be rotatable about a rotation axis Ax2. The rotation axis Ax2 is the central axis of the output shaft 43 and extends in a direction intersecting the axial direction of the rotation axis Ax1.

[0024] A pinion 29a of the drive device 29 is provided on the output shaft 43. The pinion 29a protrudes to the outside of the housing 36. The pinion 29a is rotatable integrally with the output shaft 43 around the rotation axis Ax2.

[0025] Here, as shown in Figures 3 and 4, the direction in which the rotation axis Ax2 extends is referred to as the "vertical direction DZ," the direction in which the arm portion 63b of the stopper plate 63 described later extends is referred to as the "width direction DX," and the direction in which the recesses 63c of the stopper plate 63 are arranged side by side is referred to as the "front-to-back direction DY."

[0026] (Regarding the rotation transmission mechanism 35) 3, the first reduction gear unit 41 has a worm 51 and a worm wheel 52 as a gear unit. The worm 51 is coupled to the motor shaft of the motor 31 and rotates integrally with the motor shaft about the rotation axis Ax1.

[0027] 3 and 4, the worm wheel 52 is supported by the housing 36 and the output shaft 43 so as to be rotatable about the rotation axis Ax2. The worm wheel 52 is formed in a substantially disk shape centered on the rotation axis Ax2, and is supported by the housing 36 via a biasing member 39 such as a disc spring.

[0028] In the first reduction gear unit 41, when the worm 51 rotates around the rotation axis Ax1 by the driving force of the motor 31, the worm wheel 52, which has teeth that mesh with the worm 51, rotates around the rotation axis Ax2. The first reduction gear unit 41 rotates the worm wheel 52 at a reduced speed relative to the motor shaft of the motor 31.

[0029] The second reduction gear section 42 has an eccentric shaft section 61 protruding from the worm wheel 52, an external gear 62 as a second gear, a stopper plate 63 as a restricting member, and an internal gear 64 as a third gear. In this embodiment, the eccentric shaft section 61 is joined and integrated with the worm wheel 52. The eccentric shaft section 61 and the worm wheel 52 form a first gear 69. The configuration of the first gear 69 will be described later.

[0030] The components that make up the second speed reducing portion 42 will now be described. (Regarding the eccentric shaft portion 61) 3 and 4, the eccentric shaft portion 61 protrudes from the worm wheel 52 along the rotation axis Ax3. The rotation axis Ax3 is parallel to the rotation axis Ax2 and is located at a different position from the rotation axis Ax2. In other words, the rotation axis Ax3, which is the center of the eccentric shaft portion 61, is eccentric from the rotation axis Ax2, which is the center of the worm wheel 52.

[0031] An insertion hole 61c is provided in a tip surface 61b of the eccentric shaft portion 61 on the internal gear 64 side. The center of the insertion hole 61c is coaxial with the rotation axis Ax2. The rotation axis Ax3, which is the center of the outer circumferential surface 61a of the eccentric shaft portion 61, is eccentric from the rotation axis Ax2. As will be described later, the output shaft 43 is inserted through the insertion hole 61c of the eccentric shaft portion 61 so as to be relatively rotatable.

[0032] The eccentric shaft portion 61 can rotate integrally with the worm wheel 52. The worm wheel 52, which rotates around the rotation axis Ax2, moves at least the outer peripheral surface 61a of the eccentric shaft portion 61 in the circumferential direction of the rotation axis Ax2. In other words, the eccentric shaft portion 61 revolves around the rotation axis Ax2. Together with the eccentric shaft portion 61, the rotation axis Ax3 also moves (revolves) in the circumferential direction of the rotation axis Ax2.

[0033] (Regarding stopper plate 63) 3, the stopper plate 63 is located between the worm wheel 52 and the external gear 62 in the axial direction of the rotation axis Ax2. The stopper plate 63 is supported by the housing 36 and supports the external gear 62.

[0034] 5 and 6, the stopper plate 63 has a substantially diamond-shaped main body 63a. Two pairs of opposing corners of the main body 63a are configured to be positioned along the front-rear direction DY and the width direction DX, respectively.

[0035] The main body 63a has a pair of arms 63b extending from the center in the front-rear direction DY on both sides in the width direction DX. One of the pair of arms 63b has a bifurcated branch 63e.

[0036] The main body 63a has a pair of recesses 63c cut out inward in the front-rear direction DY at the center in the width direction DX. A circular through-hole 63d is formed in the center of the main body 63a.

[0037] 6, the main body 63a of the stopper plate 63 has a protrusion 63f. This protrusion 63f is located between one of the pair of recesses 63c and one of the pair of arm portions 63b, and protrudes from the main body 63a in a direction along the plate surface of the stopper plate 63. The presence of this protrusion 63f makes it easy to visually identify the front and back of the stopper plate 63.

[0038] For example, suppose the front side of the stopper plate 63 shown in Fig. 6 is the front side. If the stopper plate 63 is to be placed inside out in the housing 36, the position of the protrusion 63f will be different, allowing the worker to easily notice that the stopper plate 63 is upside down.

[0039] Furthermore, in the assembly process of the gear device 32, it is assumed that a plurality of stopper plates 63 are prepared in a stacked state in advance, and then removed one by one and assembled to a plurality of housings 36. At this time, by stacking the stopper plates while aligning the positions of the protrusions 63f, it is possible to easily prevent the mixing of stopper plates 63 with their front and back reversed. The jig used to stack the plurality of stopper plates 63 in advance may be configured so that when attempting to stack reversed stopper plates 63, the protrusions 63f interfere and prevent stacking.

[0040] The shape of the protrusion 63f is not particularly limited, and may be a recess. Any shape can be adopted as long as it is within the range that is acceptable as the performance required for the stopper plate 63.

[0041] As shown in FIGS. 5 and 6, the arm portions 63b of the stopper plate 63 are configured to be able to be housed in the pair of housing chambers a of the housing . 6 and 7, the storage chamber 36a of the housing 36 is configured in a shape recessed outward along the width direction DX at both ends in the width direction DX on the inner periphery of the housing 36. The storage chamber 36a has a peripheral wall 36b and a bottom wall 36c, and is open upward in the vertical direction DZ and inward in the width direction DX.

[0042] One of the storage chambers 36a has a protruding wall 36d that protrudes upward from the bottom wall 36c. The protruding wall 36d is continuous with the peripheral wall 36b. The protruding wall 36d has a first protruding wall 36d1 that is continuous with the peripheral wall 36b, and a second protruding wall 36d2 that is continuous with the first protruding wall 36d1. The first protruding wall 36d1 and the second protruding wall 36d2 extend along the width direction DX.

[0043] 8, the upward protrusion height of the first protruding wall 36d1 is greater than the protrusion height of the second protruding wall 36d2 in the same direction and is greater than the thickness of the arm portion 63b. The protrusion height of the second protruding wall 36d2 is smaller than the thickness of the arm portion 63b.

[0044] 7, the upper end portion, which is the tip portion of the first convex wall 36d1, has a tapered surface F1. Specifically, when the first convex wall 36d1 is viewed from the width direction DX, the tapered surface F1 is provided so that the tip portion of the first convex wall 36d1 has a tapered shape.

[0045] Furthermore, when the storage chamber 36a is viewed from the width direction DX, the peripheral wall 36b of the storage chamber 36a has an inclined surface F2 inclined outward in the front-to-rear direction DY at the center in the up-down direction DZ. By providing the inclined surface F2, the dimension of the storage chamber 36a in the front-to-rear direction DY is larger above than at the center in the up-down direction DZ. In other words, the storage chamber 36a is configured so that the opening at the upper end is relatively large.

[0046] Because the protruding height of the first convex wall 36d1 is greater than the thickness of the arm 63b, the tip is tapered, and the opening at the upper end of the accommodation chamber 36a is relatively large, the arm 63b can be guided and accommodated in the accommodation chamber 36a. Specifically, even if the position of the arm 63b is slightly misaligned relative to the accommodation chamber 36a when the arm 63b is accommodated in the accommodation chamber 36a, the arm 63b preferentially abuts against the first convex wall 36d1 and the peripheral wall 36b of the accommodation chamber 36a, and can be easily guided to the correct position. Furthermore, because the protruding height of the second convex wall 36d2 is smaller than the thickness of the arm 63b, excessive interference between the second convex wall 36d2 and the arm 63b is suppressed, making it easier to accommodate the arm 63b. These factors make it easier to accommodate the arm 63b in the accommodation chamber 36a.

[0047] Therefore, the fact that the protruding height of the first convex wall 36d1 is greater than the thickness of the arm portion 63b, the tip of the first convex wall 36d1 is tapered, and the opening at the upper end of the storage chamber 36a is relatively large each function as a guide portion.

[0048] The above-mentioned guide portion does not necessarily have to have all of the following: the protruding height of the first convex wall 36d1 is greater than the thickness of the arm portion 63b, the tip of the first convex wall has a tapered shape, and the opening at the upper end of the storage chamber 36a is relatively large. It may have one or more of the above-mentioned guide portions. The guide portion may be omitted.

[0049] 8, when arm portion 63b is accommodated in accommodation chamber 36a, first protruding wall 36d1 and second protruding wall 36d2 are sandwiched between the bifurcated portion of arm portion 63b, and extend from peripheral wall 36b toward branched portion 63e of arm portion 63b.

[0050] With the arm portion 63b accommodated in the accommodation chamber 36a of the housing 36, the stopper plate 63 is able to move linearly in the width direction DX, but is restricted from moving linearly in the front-to-rear direction DY. Specifically, the arm portion 63b abuts against the peripheral wall 36b of the accommodation chamber 36a, and the bifurcated portion of the arm portion 63b abuts against the first protruding wall 36d1 and the second protruding wall 36d2, thereby restricting the linear movement of the arm portion 63b in the front-to-rear direction DY.

[0051] When a force is applied to the stopper plate 63 to rotate it, the force can be received not only by the peripheral wall 36b of the accommodation chamber 36a but also by the first convex wall 36d1 and the second convex wall 36d2. Because the force applied from the arm portion 63b can be received in a dispersed manner, the durability of the accommodation chamber 36a and the arm portion 63b can be improved.

[0052] Although the branch portion 63e is provided only on one arm portion 63b, it may be provided on both arms 63b. Similarly, the protruding wall 36d provided on the storage chamber 36a of the housing 36 may be provided on both storage chambers 36a, not just on one storage chamber 36a.

[0053] (Regarding external gear 62) As shown in Figures 3 and 4, the external gear 62 has a circular plate-shaped main body 62a centered on the rotation axis Ax3 and a flange 62b provided on the underside of the main body 62a in the up-down direction DZ. The outer diameter of the flange 62b is larger than the outer diameter of the main body 62a. A plurality of external teeth 62c are provided on the outer periphery of the main body 62a. The external teeth 62c protrude radially outward from the main body 62a about the rotation axis Ax3 and are arranged at approximately equal intervals around the rotation axis Ax3. An insertion hole 62d extending along the rotation axis Ax3 is provided in the center of the main body 62a.

[0054] 9 and 13, engagement claws 62e protruding downward in the up-down direction DZ are formed at two opposing locations on the rotation axis Ax3 of the flange portion 62b of the external gear 62. The width W1 of the engagement claws 62e in the width direction DX is configured to be slightly smaller than the width W2 of the recess 63c of the stopper plate 63 in the same direction.

[0055] As shown in FIGS. 10 and 12, the distance D1 between the engaging claws 62e is set larger than the distance D2 between the tip ends of the recesses 63c of the stopper plate 63. When the external gear 62 is placed on the stopper plate 63 and the engaging claws 62e of the external gear 62 are housed in the recesses 63c of the stopper plate 63, the external gear 62 becomes able to move linearly in the front-to-rear direction DY relative to the stopper plate 63 by the difference between the above-mentioned intervals D1 and D2. In addition, the linear movement of the external gear 62 in the width direction DX relative to the stopper plate 63 is restricted.

[0056] FIG. 11 shows a state in which the lower surface side of the external gear 62 faces up, in other words, a state in which the external gear 62 is turned upside down. 11 and 13, the engagement claw 62e is configured as a columnar shape with a rectangular cross section that protrudes along the thickness direction of the external gear 62. The engagement claw 62e has a pair of opposing first side walls 65 and a pair of opposing second side walls 66. The opposing direction of the first side walls 65 is along the front-to-rear direction DY, which is the direction of linear movement of the external gear 62.

[0057] As shown in FIGS. 11 and 13, the engagement claw 62e has a tapered surface F3 around the entire periphery of the protruding tip. In other words, all four corners at the tip of the engagement claw 62e have tapered surfaces F3. Furthermore, four sides extending from the base end of the engagement claw 62e to the four corners at the tip also have tapered surfaces F4. Because the engagement claw 62e has the tapered surfaces F3 and F4, when grease is applied between the engagement claw 62e of the external gear 62 and the recess 63c of the stopper plate 63, the grease is more likely to be retained on the tapered surfaces F3 and F4. Retaining the grease on the tapered surfaces F3 and F4 can prevent the grease from being swept away when the external gear 62 moves linearly. Therefore, the tapered surfaces F3 and F4 of the engagement claw 62e function as grease reservoirs. The tapered surfaces F3 and F4 of the engaging claw 62e do not need to be formed at all the locations, but may be formed partially.

[0058] Of the four corners at the tip of the engaging claw 62e, it is preferable to provide tapered surfaces F3 and F4 on the corner that contacts the first side wall 65 located radially outward of the external gear 62 and on the side that contacts the second side wall 66 of the first side wall 65 located radially outward of the external gear 62. This results in a grease reservoir being provided on the movement direction side with respect to linear movement along the radial direction of the external gear 62. This makes it possible to preferably prevent grease from being spilled radially outward. Furthermore, by providing the tapered surface F4 on the side, a grease reservoir is provided over a wider range on the movement direction side.

[0059] The shape of the grease reservoir is not limited to the tapered surfaces F3 and F4. A recess may be provided on the surface of the first side wall 65 or the second side wall 66 of the engaging claw 62e, and grease may be held in this recess. Alternatively, a tapered surface may be provided on the periphery of the recess 63c of the stopper plate 63, forming a gap between the engaging claw 62e and the tapered surface, and this gap may function as the grease reservoir.

[0060] The grease reservoir may be omitted. In the present embodiment, the engaging claws 62e of the external gear 62 are configured to be housed in the recesses 63c of the stopper plate 63, but this is not limited to this. Recesses may be provided in the external gear 62 and engaging claws may be provided in the stopper plate 63, and the engaging claws of the stopper plate 63 may be housed in the recesses of the external gear 62. In other words, the relationship of the recesses and protrusions where the external gear 62 and the stopper plate 63 engage may be reversed.

[0061] (Regarding internal gear 64) 3 and 4, the internal gear 64 has a circular plate-shaped main body 64a and a flange 64b provided on the underside of the main body 64a in the up-down direction DZ. The outer diameter of the flange 64b is larger than the outer diameter of the main body 64a. A plurality of internal teeth 64c are provided on the inner periphery of the flange 64b.

[0062] The internal teeth 64c protrude radially inward from the flange portion 64b about the rotation axis Ax2 and are arranged at approximately equal intervals around the circumference of the rotation axis Ax2. The number of the internal teeth 64c is greater than the number of the external teeth 62c. For example, the number of the internal teeth 64c is greater than the number of the external teeth 62c by one or two.

[0063] An insertion hole 64d is provided in the center of the main body 64a of the internal gear 64. The center of this insertion hole 64d is coaxial with the rotation axis Ax2. The output shaft 43 is attached while passing through this insertion hole 64d. The internal gear 64 and the output shaft 43 are configured to be rotatable together.

[0064] The materials for the stopper plate 63, external gear 62, internal gear 64, output shaft 43, eccentric shaft portion 61, and worm wheel 52 are not particularly limited, but metal is preferred because it has excellent mechanical strength and heat resistance.

[0065] (Assembling mechanism for second reduction gear portion 42) As shown in FIG. 3, the biasing member 39 is disposed within the housing 36, and a first gear 69 composed of an eccentric shaft portion 61 and a worm wheel 52 is further accommodated therein. Next, a stopper plate 63 serving as a restricting member is disposed on the first gear 69. The arm portion 63b of the stopper plate 63 is accommodated in the accommodation chamber 36a of the housing 36, and the eccentric shaft portion 61 is inserted into the through-hole 63d of the stopper plate 63. Next, an external gear 62 serving as a second gear is disposed on the stopper plate 63. The engaging claws 62e of the external gear 62 are accommodated in the recesses 63c of the stopper plate 63. Next, the output shaft 43 is inserted through the insertion hole 62d of the external gear 62 and the insertion hole 61c of the eccentric shaft portion 61, and an internal gear 64 serving as a third gear is attached. At least one of the internal teeth 64c of the internal gear 64 is meshed with at least one of the external teeth 62c of the external gear 62. Furthermore, the cover 37 is attached to the housing 36 using screws 38. A through hole 37a is provided in the cover 37, and the pinion 29a provided on the output shaft 43 protrudes to the outside of the housing 36 through this through hole 37a.

[0066] The biasing member 39 may be omitted. That is, the components constituting the second speed reducing section 42 may be assembled without using the biasing member 39. The biasing member 39 is not limited to a disc spring, and may be rubber or a spring.

[0067] 3 and 4, the cover 37 has a groove 37b that curves around the through hole 37a and protrudes downward in the up-down direction DZ, which is the thickness direction. The groove 37b is formed in a ring shape around the through hole 37a by bead processing.

[0068] 4, when viewed from the front-rear direction DY, the groove 37b is provided in a position closer to the outer peripheral edge between the center and the outer peripheral edge of the internal gear 64 in the width direction DX. Similarly, when viewed from the width direction DX, the groove 37b is provided in a position closer to the outer peripheral edge between the center and the outer peripheral edge of the internal gear 64 in the front-rear direction DY. In addition, the apex P of the groove 37b abuts against the internal gear 64.

[0069] The cover 37 has the grooves 37b, which improves the strength of the cover 37 in the thickness direction, thereby suppressing deformation of the cover 37 in the thickness direction. The grooves 37b function as deformation suppressing portions.

[0070] By forming the groove portion 37b by bead processing, the deformation suppression portion can be provided by a simpler method. As shown in FIG. 4 , the housing 36 contains a biasing member 39, an eccentric shaft 61, a worm wheel 52, a stopper plate 63, an external gear 62, an internal gear 64, and other components. As described below, the external gear 62 is eccentric relative to the rotation of the worm wheel 52, thereby slowing down the rotation of the internal gear 64. Within the housing 36, an upward biasing force in the vertical direction DZ is generated by the repulsive force of the biasing member 39. Furthermore, because multiple components operate in conjunction with each other within the housing 36, upward stress tends to be large. These biasing forces and stresses tend to cause the outer periphery of the internal gear 64 to move upward, which in turn tends to deform the cover 37. In this embodiment, the groove 37b is provided between the center and outer periphery of the internal gear 64 in the width direction DX, closer to the outer periphery. This effectively suppresses deformation of the cover in the thickness direction. Furthermore, since the apex P of the groove portion 37b abuts against the internal gear 64, deformation of the cover in the thickness direction can be more suitably suppressed.

[0071] The shape of the deformation suppressing portion is not limited to the shape of the groove portion 37b. For example, the thickness of the cover 37 may be locally increased, or a reinforcing material may be locally attached to the cover 37, thereby suppressing deformation.

[0072] The position of the groove 37b is not limited to a position closer to the outer peripheral edge of the internal gear 64 in the width direction DX. It may be an intermediate point between the center and outer peripheral edge of the internal gear 64 in the width direction DX, or a position closer to the center. The apex P of the groove 37b provided in the cover 37 is close to the internal gear 64 but does not necessarily have to abut against it.

[0073] The deformation suppressing portion of the cover 37 may be omitted. (Operation mechanism of second reduction gear unit 42) When the worm wheel 52 constituting the first gear 69 rotates around the rotation axis Ax2, the eccentric shaft portion 61 revolves around the rotation axis Ax2. Because the external gear 62 is disposed on the stopper plate 63 as described above, it is restricted from rotating together with the eccentric shaft portion 61. The external gear 62 is moved in the circumferential direction of the rotation axis Ax2 while tracing a circular locus whose radius is the distance between the rotation axis Ax2 and the rotation axis Ax3. In other words, the external gear 62 revolves around the rotation axis Ax2.

[0074] When the external gear 62 revolves, the external teeth 62c of the external gear 62 move in the circumferential direction of the rotation axis Ax2. Because the number of internal teeth 64c of the internal gear 64 is greater than the number of external teeth 62c, the meshing portion between the internal teeth 64c and the external teeth 62c moves around the rotation axis Ax2 as the external gear 62 revolves. The meshing portion between the internal teeth 64c and the external teeth 62c moves around the rotation axis Ax2, causing the internal gear 64 to rotate around the rotation axis Ax2. For one revolution of the external gear 62, the internal gear 64 rotates by an amount corresponding to the movement of the meshing portion between the internal teeth 64c and the external teeth 62c. Therefore, the rotation of the internal gear 64 is decelerated relative to the rotation of the worm wheel 52. In other words, the internal gear 64 rotates at a slower speed than the rotation speed of the first gear 69. The second reduction gear unit 42 performs deceleration using a so-called Taumel mechanism.

[0075] (Operations and Effects of the Present Embodiment) (1) The stopper plate 63 has an arm 63b extending in the direction of linear movement of the stopper plate 63. The housing 36 has an accommodation chamber 36a that accommodates the arm 63b, and the arm 63b has a branched portion 63e that branches into two or more branches. The accommodation chamber 36a has a protruding wall 36d that is disposed at the branched portion 63e.

[0076] When a force is applied to the stopper plate 63 to rotate it, the force can be received not only by the accommodation chamber 36a but also by the convex wall 36d. Since the force applied from the arm portion 63b can be received in a dispersed manner, the durability of the accommodation chamber 36a and the arm portion 63b can be improved.

[0077] (2) The accommodation chamber 36a of the housing 36 has a guide portion that guides the arm portion 63b of the stopper plate 63 when the arm portion 63b is accommodated in the accommodation chamber 36a. Therefore, when the arm portion 63b is accommodated in the accommodation chamber 36a, the arm portion 63b can be accommodated while being guided, which makes it easy to accommodate the arm portion 63b in the accommodation chamber 36a.

[0078] (3) The guide portion is provided on the protruding wall 36d. Therefore, even if the accommodation chamber 36a has the protruding wall 36d, it is easy to accommodate the arm portion 63b. (4) The accommodation chamber 36a has a peripheral wall 36b, and the guide portion is provided on the peripheral wall 36b. Therefore, the peripheral wall 36b can be effectively used as the guide portion.

[0079] (5) The protruding wall 36d includes a first protruding wall 36d1 extending continuously from the peripheral wall 36b and a second protruding wall 36d2 extending continuously from the first protruding wall 36d1 toward the branched portion 63e of the arm 63b. The protruding height of the first protruding wall 36d1 is greater than the protruding height of the second protruding wall 36d2 and greater than the thickness of the arm 63b. Therefore, when the arm 63b is accommodated in the accommodation chamber 36a, even if the position of the arm 63b is slightly misaligned with respect to the accommodation chamber 36a, the arm 63b preferentially abuts against the first protruding wall 36d1. This allows the arm 63b to be easily guided to the correct position.

[0080] (Other embodiments) This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0081] In the present embodiment, the second gear is the external gear 62 and the third gear is the internal gear 64, but this is not limiting. The second gear may be an internal gear and the third gear may be an external gear.

[0082] In the present embodiment, the gear device 32 includes the rotation transmission mechanism 35, the housing 36, and the cover 37. The rotation transmission mechanism 35 further includes the first reduction gear unit 41, the second reduction gear unit 42, and the output shaft 43. However, this is not limiting. The first reduction gear unit 41 of the rotation transmission mechanism 35 may be omitted. That is, the rotation transmission mechanism 35 may be configured to directly reduce the rotation of the motor 31 using the second reduction gear unit 42. In this embodiment, a normal external gear may be used as the gear unit instead of the worm wheel 52.

[0083] Although the gear device 32 of the present embodiment is used in a seat lifter device that raises and lowers the vehicle seat 11, the present invention is not limited to this. The gear device 32 can be used in any gear device that has a Taumel mechanism. Examples of gear devices that have a Taumel mechanism include gear devices that slide a seat in the front-rear direction and gear devices that adjust the tilt of a seat back. [Explanation of symbols]

[0084] DX...width direction, DY...front-rear direction, DZ...front-rear direction, Ax1...rotation axis, Ax2...rotation axis, Ax3...rotation axis, W1...width of engaging claw, W2...width of notch, D1...spacing between engaging claws, D2...spacing between the tips of notches, F1...tapered surface, F2...inclined surface, F3...tapered surface, F4...tapered surface, P...vertex, 1...floor, 11...seat, 12...slide rail, 21...upper rail, 22...lower rail, 23...bracket, 24...pin, 25 ...Cushion frame, 26...Front link, 27...Rear link, 27a...Gear, 28...Rod, 29...Driver, 29a...Pinion, 31...Motor, 31a...Case, 32...Gear device, 35...Rotation transmission mechanism, 36...Housing, 36a...Accommodation chamber, 36b...Peripheral wall, 36c...Bottom wall, 36d...Convex wall, 36d1...First convex wall, 36d2...Second convex wall, 37...Cover, 37a...Through hole, 37b...Groove portion, 38...Screw, 39...Biasing member, 4 1...first reduction gear portion, 42...second reduction gear portion, 43...output shaft, 51...worm, 52...worm wheel, 61...eccentric shaft portion, 61a...outer peripheral surface, 61b...tip surface, 61c...insertion hole, 61d...protruding wall, 61e...inner peripheral surface, 62...externally toothed gear (second gear), 62a...main body portion, 62b...flange portion, 62c...external teeth, 62d...insertion hole, 62e...engagement claw, 63...stopper plate, 63a...main body portion, 63b...arm portion, 63c...recess, 63d...through hole , 63e...branch portion, 63f...protrusion, 64...internal gear (third gear), 64a...main body portion, 64b...flange portion, 64c...internal teeth, 64d...insertion hole, 65...first side wall, 66...second side wall, 69...first gear, 70...gear device, 71...worm gear (worm wheel), 72...external gear, 72a...engaging claw, 73...internal gear, 74...eccentric shaft portion, 75...first gear, 76...stopper plate, 76a...recess, 77...housing, 78...cover.

Claims

1. A gear device including a first gear, a second gear that becomes eccentric as the first gear rotates, and a third gear that rotates at a speed slower than the rotational speed of the first gear as the second gear becomes eccentric, a stopper plate that engages with the second gear in a concave-convex relationship to restrict rotational movement while allowing linear movement of the second gear; a housing that accommodates the stopper plate in a state in which linear movement of the stopper plate is permitted while rotational movement of the stopper plate is restricted, the stopper plate has an arm portion extending along a direction of linear movement of the stopper plate, and the housing has an accommodating chamber that accommodates the arm portion, the arm portion has a branch portion that branches into two or more branches, and the storage chamber has a convex wall that is disposed at the branch portion, The chamber has a peripheral wall, the protruding wall includes a first protruding wall extending continuously from the peripheral wall and a second protruding wall extending continuously from the first protruding wall toward the branched portion of the arm portion, the first convex wall has an upper end tapered, A gear device, characterized in that a protruding height of the first protruding wall is greater than a protruding height of the second protruding wall, is greater than a thickness of the arm portion, and is smaller than a height of the peripheral wall.

2. 2. The gear device according to claim 1, wherein the accommodation chamber of the housing has a guide portion that guides the arm portion of the stopper plate when the arm portion is accommodated in the accommodation chamber.

3. The gear device according to claim 2 , wherein the guide portion is provided on the convex wall.

4. The chamber has a peripheral wall, The gear device according to claim 2 , wherein the guide portion is provided on the peripheral wall.

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