Motor with speed reduction mechanism

Abstract

To provide a structure which enables downsizing of a speed reduction mechanism adopting a resin housing.SOLUTION: A guide plate 80 disposed between a first housing 31 and a second housing 32 is formed with a plurality of attachment holes 83. Metallic collars 85 are respectively press-fitted into the attachment holes 83. Insertion holes 31d, 32d which are arranged coaxially with the attachment holes 83 and have large inner diameters allowing the collars 85 to inserted thereinto are respectively formed at the first housing 31 and the second housing 32.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a motor with a speed reduction mechanism. [Background technology]

[0002] A known example of a conventional technique for a motor with a speed reduction mechanism is the geared motor disclosed in Patent Document 1 below. This geared motor is configured to include a case consisting of a resin case body and case cover, a worm and worm gear, an eccentric shaft portion formed integrally with the worm gear and eccentric with respect to the output shaft, a gear plate rotatably supported on the eccentric shaft portion and integrally provided with an external gear concentric with the eccentric shaft portion, an output shaft formed with an internal gear that partially meshes with the external gear, and a guide plate disposed between the gear plate and the worm gear and guiding the gear plate so that it can revolve but cannot rotate on its axis. The case body and case cover are each formed with three mounting holes through which bolts for connecting the case to a workpiece are inserted, and collars are inserted into each mounting hole.

[0003] In this configuration, an external load applied in reverse from the output shaft during a collision or the like is distributed to the case body and case cover via the gear plate and guide plate, and then transmitted from the case body and case cover to the mounting member individually via the collar and bolt. Therefore, even if the case body and case cover are made of resin, the necessary strength can be ensured. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-099085 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because the external force (external load) transmitted from the output shaft to the collar via the case body and the case cover is generated as the output shaft tries to rotate in response to the external force, the shorter the distance between the rotational axis of the output shaft and the collar and mounting hole becomes, the greater the force becomes. For this reason, in a configuration using a resin housing as described above, it is necessary to position the mounting hole and collar farther away from the rotational axis of the output shaft, which makes it difficult to reduce the size of the reduction gear mechanism.

[0006] The present invention has been made to solve the above-mentioned problems, and its object is to provide a configuration that can reduce the size of a reduction mechanism that uses a resin housing. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides A motor body (21), a reduction mechanism (23); A motor (20) with a reduction mechanism, The reduction mechanism is a worm gear (33) that rotates by the rotational force transmitted from the motor body; a worm wheel (34) meshing with the worm gear; a first housing (31) that rotatably accommodates the worm gear and the worm wheel; an eccentric body (40) that rotates together with the worm wheel and has an outer peripheral surface (43) centered on an eccentric axis (L2) that is parallel to the rotation axis (L1) of the worm wheel; a gear plate (50) on which an external gear (52) is formed and which is journaled on the outer peripheral surface and has its center on the eccentric axis; an output shaft (60) on which an internal gear (62) is formed, the internal gear partially meshing with the external gear; a second housing (32) that supports the output shaft so that the output shaft rotates around the rotation axis; an Oldham plate (70) made of metal that guides the gear plate slidably in a predetermined direction perpendicular to the rotation axis; a metal guide plate (80) interposed between the first housing and the second housing to slidably guide the Oldham plate in a direction perpendicular to both the rotation axis and the predetermined direction; Equipped with The guide plate has a plurality of mounting holes (83), A metal collar (85) is press-fitted into the mounting hole, The first housing and the second housing are characterized in that insertion holes (31d, 32d) are formed in the first housing and the second housing, respectively, which are coaxial with the mounting hole, have a large inner diameter, and through which the collar is inserted. The symbols in parentheses above indicate the correspondence with the specific means described in the embodiments to be described later. [Effects of the Invention]

[0008] In the present invention, the reduction gear mechanism includes a worm gear and a worm wheel, a first housing that rotatably accommodates the worm gear and the worm wheel, an eccentric that rotates with the worm wheel and has an outer circumferential surface centered on an eccentric axis parallel to the rotation axis of the worm wheel, a gear plate that is journaled on the outer circumferential surface and has an external gear centered on the eccentric axis, an output shaft that has an internal gear that partially meshes with the external gear, a second housing that journals the output shaft so as to rotate about the rotation axis, a metal Oldham plate that slidably guides the gear plate in a predetermined direction perpendicular to the rotation axis, and a metal guide plate that is interposed between the first and second housings and slidably guides the Oldham plate in directions perpendicular to both the rotation axis and the predetermined direction. The guide plate has a plurality of mounting holes formed in the mounting holes, and metal collars are press-fitted into the mounting holes, and the first and second housings each have an insertion hole that is coaxial with the mounting holes and has a large inner diameter, through which the collars are inserted.

[0009] As a result, when the motor with reduction gear mechanism is fastened to the frame of the seat or the like with a bolt that passes through the collar, external force input from the output shaft in the event of a collision or the like is transmitted to the collar via the metal Oldham plate and guide plate, but is less likely to be transmitted to the first and second housings. Because the load path passes through each metal member in this way, even if the external force transmitted to the collar increases due to the distance between the rotational axis of the output shaft and the collar and mounting hole being shortened to reduce the size of the reduction gear mechanism, the load path does not become insufficient in strength. Therefore, it is possible to achieve a motor with reduction gear mechanism that can reduce the size of the reduction gear mechanism using a plastic housing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view conceptually showing an example of a vehicle seat equipped with a power seat device including a motor with a speed reduction mechanism according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of a motor unit fastened to a seat cushion frame as viewed from one direction. [Figure 3] 10 is a perspective view of the motor unit fastened to the seat cushion frame, as viewed from another direction. FIG. [Figure 4] FIG. 4 is a front view of the motor unit fastened to the seat cushion frame. [Figure 5] FIG. 4 is a side view of the motor unit fastened to the seat cushion frame. [Figure 6] 5 is a cross-sectional view taken along a line X1-X1 shown in FIG. 4. [Figure 7] FIG. 2 is a diagram of the motor unit as seen from the output shaft side. [Figure 8] 6 is a side view of the motor unit in a state where a seat cushion frame and fastening members are removed from FIG. 5. [Figure 9] FIG. 2 is an exploded perspective view of the motor unit as viewed from one direction. [Figure 10] FIG. 4 is an exploded perspective view of the motor unit as viewed from the other direction. [Figure 11]FIG. [Figure 12] 9 is a cross-sectional view taken along a line X2-X2 shown in FIG. 8. [Figure 13] 9 is a cross-sectional view taken along a line X3-X3 shown in FIG. 8. [Figure 14] FIG. 10 is an explanatory diagram illustrating a load path that serves as a transmission path for a reversely input external force within the reduction mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0011] [First embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a power seat device including a motor with a speed reduction mechanism according to the present invention will be described below with reference to the drawings. 1, the power seat device 10 according to this embodiment is a device mounted on a vehicle seat 1 to control the posture of a seat cushion 2, and is fastened and fixed to a seat cushion frame 2a that constitutes the framework of the seat cushion 2, and is configured to be able to arbitrarily adjust the posture of the vehicle seat 1, such as the front-to-rear height of the seat cushion 2, in response to the operation of an operation switch (not shown). The power seat device 10 includes a motor unit 20 that functions as a motor with a speed reduction mechanism, and a seat posture adjustment mechanism (not shown) that adjusts the posture of the vehicle seat 1 by utilizing the rotational power transmitted via an output shaft 60 of the motor unit 20.

[0012] The motor unit 20 shown in Figures 2 to 10 includes a motor body 21, a connector 22, and a reduction mechanism 23. The motor body 21 functions to transmit the rotational power of a motor shaft (not shown), which rotates in response to operation of the operation switch, to the reduction mechanism 23 when power is supplied from an external power source via the connector 22. The motor body 21 is attached to the reduction mechanism 23 using three bolts 24a. For convenience, Figures 2 to 6 only show a portion of the seat cushion frame 2a near the location where the motor unit 20 is attached.

[0013] The reduction mechanism 23 functions as a gear box that reduces the rotational power transmitted from the motor body 21 and transmits it to the height mechanism for output. The reduction mechanism 23 includes a first housing 31 and a second housing 32 made of resin that form the main part of the outer shell, a worm gear 33, a worm wheel 34, an eccentric body 40, a gear plate 50, an output shaft 60, an Oldham plate 70, and a guide plate 80.

[0014] The worm gear 33 is coaxially connected to the motor shaft of the motor body 21 so as to rotate together with the motor shaft, and is journalled to the first housing 31 by means of bearings 25a and 25b.

[0015] 6, the first housing 31 is formed so that the worm wheel 34, which is rotatably supported by the substantially cylindrical rotating shaft 35, is constantly engaged with the worm gear 33, which is journaled as described above. A bearing 31a is formed on the bottom surface of the first housing 31 to journal a portion of the rotating shaft 35 on the non-output side.

[0016] The first housing 31 has a flange portion 31b, inside which the worm wheel 34 and the like are disposed, which has three assembly holes 31c for assembly with the second housing 32 and three insertion holes 31d through which the non-output side of the collar 85 described later is inserted.

[0017] The second housing 32 is formed with a through hole 32a through which the output shaft 60 is inserted, an annular stepped portion 32b that receives the output side of the housing 64 of the output shaft 60 via a washer 36, three assembly holes 32c for assembly with the first housing 31, and three insertion holes 32d through which the output sides of collars 85 (described later) are inserted. Each assembly hole 32c has a stepped shape and is formed so that its small diameter portion facing the first housing 31 is approximately concentric with and its large diameter portion is approximately concentric with, the respective assembly holes 31c of the first housing 31. Each insertion hole 32d is formed so that it is approximately concentric with and the respective insertion holes 31d of the first housing 31.

[0018] The eccentric body 40 is a member that rotates together with the rotary shaft 35, and is formed with a through hole 41 into which the rotary shaft 35 passes and is fitted, and external teeth 42 for fitting with the worm wheel 34. The eccentric body 40 is supported so as to rotate together with the rotary shaft 35 and the worm wheel 34 about the rotation axis L1 of the rotary shaft 35, with the through hole 41 fitted to the rotary shaft 35 and the external teeth 42 fitted to the inner peripheral side of the worm wheel 34.

[0019] As shown in FIG. 11, the eccentric body 40 has an outer peripheral surface 43 on the output side, the outer peripheral surface 43 being centered on an eccentric axis L2 that is parallel to and offset a predetermined distance from the rotation axis L1 of the rotary shaft portion 35.

[0020] The gear plate 50 is made of metal and has a through hole 51 journaled on the outer peripheral surface 43 of the eccentric body 40, an externally toothed gear 52 whose center coincides with that of the through hole 51, and a pair of protrusions 53a, 53b formed therein. Since the gear plate 50 is journaled on the outer peripheral surface 43 of the eccentric body 40 by the through hole 51, when the eccentric body 40 rotates about the rotation axis L1 of the rotating shaft portion 35, the gear plate 50 revolves around the rotation axis L1.

[0021] The pair of protrusions 53a, 53b are arranged on the counter-output side surface opposite the output side surface on which the external gear 52 is arranged, facing each other through a through hole 51 and each protruding convexly toward the counter-output side.

[0022] The Oldham plate 70 is a metal plate interposed inside the guide plate 80. The Oldham plate 70 is formed with an opening 71 through which the rotating shaft portion 35 and the outer peripheral surface 43 of the eccentric body 40 are inserted, a pair of guide portions 72a, 72b facing each other via the opening 71, and a pair of extending portions 73a, 73b extending in opposite directions to each other via the opening 71 in a direction perpendicular to the facing direction of the guide portions 72a, 72b.

[0023] The guide portions 72a, 72b are formed so that their groove widths and the like correspond to the shapes of the protrusions 53a, 53b of the gear plate 50 and guide the protrusions 53a, 53b slidably in a first guide direction (the up-and-down direction in FIG. 12) perpendicular to the rotation axis L1. The first guide direction can be an example of the "predetermined direction."

[0024] The guide plate 80 is a metal plate interposed between the first housing 31 and the second housing 32. The guide plate 80 has an opening 81 through which the Oldham plate 70 is interposed, three insertion holes 82, and three mounting holes 83. Each insertion hole 82 is formed so as to be substantially concentric and have the same diameter as each assembly hole 31c of the first housing 31. Each mounting hole 83 is formed so as to be concentric with each insertion hole 31d of the first housing 31 and each insertion hole 32d of the second housing 32, but have a slightly smaller diameter.

[0025] A pair of guide portions 84a, 84b are formed on the inner edge that defines the opening 81. The guide portions 84a, 84b are formed such that their groove widths and the like correspond to the shapes of the extending portions 73a, 73b of the Oldham plate 70, and they slidably guide the extending portions 73a, 73b in a second guide direction (the left-right direction in FIG. 12 ) that is perpendicular to both the rotation axis L1 and the first guide direction.

[0026] Therefore, by guiding both protruding portions 53a, 53b of the gear plate 50 to both guide portions 72a, 72b of the Oldham plate 70 and by guiding both extending portions 73a, 73b of the Oldham plate 70 to both guide portions 84a, 84b of the guide plate 80, the gear plate 50 is supported so as to be movable along a plane perpendicular to the rotation axis L1 during the above-mentioned revolution.

[0027] A collar 85 for fastening to the seat cushion frame 2a is press-fitted into each mounting hole 83. The collar 85 is formed by molding a metal plate into a substantially cylindrical shape. The collar 85 is inserted into the insertion hole 31d of the first housing 31 and the insertion hole 32d of the second housing 32 without coming into contact with them, and is formed so as to protrude slightly from both insertion holes 31d, 32d.

[0028] The output shaft 60 is equipped with a pinion gear 61 and an internal gear 62 for transmitting reduced rotational power to the seat posture adjustment mechanism, and an insertion hole 63 is formed inside the internal gear 62 into which the output side of the rotating shaft portion 35 is inserted.

[0029] The output shaft 60 is supported by the second housing 32 and the rotary shaft portion 35 so as to rotate about the rotation axis L1 of the rotary shaft portion 35 inserted into the insertion hole 63, with the pinion gear 61 extending through the through hole 32a. In this supported state, the output shaft 60 is pressed in the axial direction against the annular step portion 32b of the second housing 32 via the washer 36 by an annular housing 64 located on the outer circumferential side of the internal gear 62.

[0030] As shown in Figure 13, the internal gear 62 has a greater number of teeth than the external gear 52 of the gear plate 50, so that it is configured to partially mesh with the external gear 52 when in the supported state described above.

[0031] The first housing 31 and the second housing 32 are assembled in a housed state in which each component is arranged as described above, with the screws 24b inserted from each assembly hole 32c passing through the insertion holes 82 of the guide plate 80 and the assembly holes 31c of the first housing 31, and then fastened using the fasteners 24c.

[0032] 2 to 6, the motor unit 20 configured in this manner is fastened to threaded holes in the seat cushion frame 2a by bolts 11 that are inserted into the insides of the collars 85 from the first housing 31 side so as to be capable of transmitting rotational power to the seat position adjustment mechanism via the pinion gear 61 of the output shaft 60. The bolts 11 may also be fastened to the seat cushion frame 2a using nuts or the like.

[0033] In the motor unit 20 fastened and fixed in this manner, when the worm gear 33 rotates due to the rotational force transmitted from the motor main body 21, the worm wheel 34 and the eccentric body 40 rotate about the rotation axis L1 of the rotation shaft portion 35. The gear plate 50, which is journaled on the outer peripheral surface 43 of the eccentric body 40, revolves around the rotation axis L1 with the external gear 52 partially meshing with the internal gear 62 of the output shaft 60, guided by the Oldham plate 70 and the guide plate 80. As a result, the meshing portion between the external gear 52 and the internal gear 62 rotates once in the circumferential direction, and the output shaft 60 rotates in the same direction according to the difference in the number of teeth, so the rotation of the output shaft 60 is decelerated relative to the rotation of the motor shaft.

[0034] As described above, the rotational power reduced by the reduction mechanism 23 is transmitted to the seat position adjustment mechanism via the pinion gear 61 of the output shaft 60. Therefore, the position of the vehicle seat 1 can be adjusted at a predetermined speed according to the rotation direction of the motor shaft of the motor main body 21 based on the operation of the operation switch.

[0035] In this embodiment, metal collars 85, through which threaded portions of bolts 11 for fastening to the seat cushion frame 2a pass, are press-fitted into the mounting holes 83 of the metal guide plate 80 and pass without contacting the through-holes 31d of the resin first housing 31 and the through-holes 32d of the resin second housing 32. The reason for this mounting structure, in which the collars 85 press-fitted into the guide plate 80 are used to fasten and fix the motor unit 20 to the seat cushion frame 2a in this manner, will be described below.

[0036] In the event of a collision or the like, a reverse input may occur that rotates the output shaft 60 via the seat position adjustment mechanism. Because the motor unit 20 is fastened to the seat cushion frame 2a by the bolts 11 through which the threaded portions of the collars 85 are inserted, the external force reversely input from the output shaft 60 as described above is transmitted to the metal collars 85 via the metal gear plate 50 and Oldham plate 70.

[0037] Because the collar 85 is not in contact with the insertion hole 31d of the first housing 31 and the insertion hole 32d of the second housing 32, the external force transmitted to the collar 85 as described above is transmitted to the seat cushion frame 2a without being transmitted to the first housing 31 or the second housing 32. That is, the load path that transmits the external force that is reversely input via the output shaft 60 in the reduction mechanism 23 is configured to pass through the metal members of the gear plate 50, the Oldham plate 70, and the collar 85, as shown by the arrows in FIG. 14. Therefore, even in the reduction mechanism 23 in which the first housing 31 and the second housing 32 that are made of resin form the main parts of the outer shell, the strength required for the reverse input as described above can be ensured.

[0038] As described above, in the motor unit 20 according to this embodiment, the reduction mechanism 23 includes the worm gear 33 and the worm wheel 34, the first housing 31 that rotatably accommodates the worm gear 33 and the worm wheel 34, the eccentric body 40 that rotates together with the worm wheel 34 and has an outer circumferential surface 43 that is centered on an eccentric axis L2 that is parallel to the rotation axis L1 of the worm wheel 34, the gear plate 50 that is journaled at the outer circumferential surface 43 and has an external gear 52 that is centered on the eccentric axis L2, and The gear plate 50 includes an output shaft 60 on which an internal gear 62 is formed, which is partially meshed with the output shaft 60, a second housing 32 that supports the output shaft 60 so as to rotate about a rotation axis L1, a metal Oldham plate 70 that slidably guides the gear plate 50 in a first guide direction (a predetermined direction) perpendicular to the rotation axis L1, and a metal guide plate 80 that is interposed between the first housing 31 and the second housing 32 and slidably guides the Oldham plate 70 in a second guide direction perpendicular to both the rotation axis L1 and the first guide direction. A plurality of mounting holes 83 are formed in the guide plate 80, and metal collars 85 are press-fitted into each mounting hole 83. The first housing 31 and the second housing 32 are each formed with insertion holes 31d, 32d that are coaxial with the mounting holes 83, have large inner diameters, and allow the collars 85 to pass through.

[0039] As a result, when the motor unit 20 is fastened to the seat cushion frame 2a with the bolt 11 having the threaded portion passing through the collar 85, an external force reversely input from the output shaft 60 during a collision or the like is transmitted to the collar 85 via the metal Oldham plate 70 and guide plate 80, but is less likely to be transmitted to the first housing 31 and the second housing 32. Because the load path passes through the metal members in this manner, even if the external force transmitted to the collar 85 increases due to the distance between the rotation axis L1 of the output shaft 60 and the collar 85 and mounting hole 83 being shortened in order to reduce the size of the reduction mechanism 23, the reduction mechanism 23 itself does not become insufficient in strength. Therefore, it is possible to realize a motor unit 20 in which the reduction mechanism 23 employing the resin housings 31, 32 can be reduced in size.

[0040] [Other embodiments] The present invention is not limited to the above-described embodiments, and may be embodied as follows, for example. (1) The present invention is not limited to being applied to the motor unit 20 of a power seat device 10 that controls the posture of a vehicle seat 1, such as the fore-and-aft height of the seat cushion 2, but may also be applied to a motor with a reduction mechanism that reduces the rotational power of a motor and outputs it in a device other than a power seat device.

[0041] (2) The collar 85 to be pressed into each mounting hole 83 of the guide plate 80 is not limited to being formed by molding a metal plate into an approximately cylindrical shape, but may also be formed, for example, from a cylindrical metal member that can be pressed into the mounting hole 83 and through which the threaded portion of the bolt 11, etc., can be inserted. [Explanation of symbols]

[0042] 1. Vehicle seat 2a Seat cushion frame 10 Power seat device 11 volts 20 Motor unit (motor with reduction mechanism) 21 Motor body 23 Reduction mechanism 31 First Housing 31d Insertion hole 32 Second Housing 32d Insertion hole 33 Worm gear 34 Worm Wheel 40 Eccentric body 43 Outer surface 50 gear plate 52 External gear 60 output shaft 62 Internal gear 70 Oldham Plate 80 Guide Plate 83 Mounting hole 85 Color L1 rotation axis L2 eccentric axis

Claims

[Claim 1] A motor body, A reduction mechanism; A motor with a reduction mechanism, The reduction mechanism is a worm gear that rotates by the rotational force transmitted from the motor body; a worm wheel that meshes with the worm gear; a first housing that rotatably accommodates the worm gear and the worm wheel; an eccentric body that rotates together with the worm wheel and has an outer circumferential surface centered on an eccentric axis that is parallel to the rotation axis of the worm wheel; a gear plate supported on the outer circumferential surface thereof and having an external gear centered on the eccentric axis; an output shaft on which an internal gear is formed that partially meshes with the external gear; a second housing that supports the output shaft so that the output shaft rotates about the rotation axis; an Oldham plate made of metal that guides the gear plate slidably in a predetermined direction perpendicular to the rotation axis; a metal guide plate interposed between the first housing and the second housing to slidably guide the Oldham plate in a direction perpendicular to both the rotation axis and the predetermined direction; Equipped with The guide plate has a plurality of mounting holes formed therein, A metal collar is press-fitted into the mounting hole, A motor with a reduction mechanism, characterized in that the first housing and the second housing each have an insertion hole that is coaxial with the mounting hole, has a large inner diameter, and through which the collar is inserted.

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