JP2023092172A - Gear structure, reduction gear, and motor unit - Google Patents

Abstract

To prevent a float and an inclination of a helical gear, and to stably support rotation.SOLUTION: In a gear structure 9 having a helical gear 10 engaged with a worm 4 which rotates integrally with a drive shaft 5, and rotates around an axial core C orthogonal to a center line S of the drive shaft 4, and a gear box 3A having an accommodation part 31 of the helical gear 10, the helical gear 10 has an annular hub 11 with the axial core C as a center, and a first recess 11b which is recessed into a substantially-columnar shape in the axial core C direction from one end face 11a of the hub 11. The accommodation part 31 has a boss part 32 cylindrically protruding from a bottom face 31a to the axial core C direction, and rotatably supporting the helical gear 10. The boss 32 is protrusively formed at a position of a virtual face F passing the center line S of the drive shaft 5, and orthogonal to the axial core C direction, or at an opening side of the accommodation part 31 rather than the virtual face F, and supports the helical gear 10 while an external peripheral face 32a of the boss 32 slides with an internal peripheral face 11b of the first recess 11b at the rotation of the accommodated helical gear 10.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to a gear structure including a helical gear housed in a gearbox, a speed reducer including this gear structure, and a motor unit including this speed reducer.

2. Description of the Related Art Conventionally, a speed reducer that uses a worm gear that combines a worm and a helical gear (worm wheel) to reduce and then output power from a drive source, and a motor unit that includes this speed reducer are known. The speed reducer is used in various applications because it is small and provides a large speed reduction ratio, and has the advantage of quiet and smooth meshing. For example, Patent Document 1 discloses a configuration in which the speed reducer is applied to a vehicle power seat device. As in Patent Document 1, in a speed reducer equipped with a worm gear, a housing (also called a gearbox) is formed with a space for accommodating a worm (a worm housing portion) and a space for housing a helical gear (a helical gear housing portion). . The speed reducer is configured such that a worm and a helical gear are accommodated in each accommodating portion in a state of meshing with each other.

Japanese Patent No. 5293023

By the way, in the case where the helical gear is housed in a bottomed cylindrical housing portion, the helical gear is rotatably supported while sliding on a wall surface provided upright from the bottom surface of the gearbox. For example, in Patent Document 1, as shown in FIG. 8, the annular protrusion (70) of the housing body (510) is fitted into the annular recess (60) of the helical gear (40), and the annular protrusion (70) ) and the outer peripheral surface (66) of the annular recess (60) are in sliding contact with each other. That is, in the case of the configuration of Patent Document 1, the surfaces indicated by reference numerals 66 and 76 (hereinafter also referred to as "sliding surfaces") are configured to slide on each other.

Since this sliding surface has a function of stably supporting the rotating helical gear, it is preferable that the area of the sliding surface is large. In this regard, in the case of the configuration of Patent Document 1, there is room for improvement because the area of the sliding surface is small. The power of the drive source is transmitted from the worm to the helical gear, and is applied to the helical gear in a direction that passes through the center of the worm and perpendicular to the axis of the helical gear. Therefore, if the sliding surface is positioned closer to the bottom than the extension of the direction in which the power is applied, the applied power acts in a direction that lifts the worm-side portion of the helical gear, causing the helical gear to rise. can occur. When the helical gear is lifted, the helical gear is tilted and becomes a cause of rattling. In addition, the helical gear may come into contact with the gear box at places other than the sliding surface, resulting in loss.

The gear structure of the present invention has been devised in view of such problems, and one of the purposes thereof is to prevent the helical gear from floating or tilting and to enable stable rotation support. Further, the speed reducer and the motor unit including the speed reducer of the present invention aim to improve the quality by stably supporting the rotation of the helical gear by using this gear structure. In addition to these purposes, it is also another object of the present invention to achieve functions and effects that are derived from each configuration shown in the modes for carrying out the invention described later and that cannot be obtained by conventional techniques. is.

(1) The gear structure disclosed herein includes a helical gear that has external teeth that mesh with a worm that rotates integrally with a drive shaft and that rotates around an axis perpendicular to the center line of the drive shaft; a gearbox having a bottom tubular housing. The helical gear has an annular hub centered on the axis, and a first concave portion recessed in a substantially cylindrical shape from one end surface of the hub in the axial direction of the axis. a bottom surface facing the one end surface in a state in which the helical gear is housed; and a boss cylindrically projecting from the bottom surface in the axial direction and supporting the helical gear rotatably. The boss protrudes at a position of a virtual plane passing through the center line of the drive shaft and perpendicular to the axial direction, or at an opening side of the housing portion from the virtual plane, and is arranged so that when the housed helical gear rotates, , the outer peripheral surface of the boss slides on the inner peripheral surface of the first recess to support the helical gear.

(2) The housing portion has an annular groove recessed in the bottom surface of the radially outer root portion of the boss, and the hub has a cylindrical wall that forms the first recess. It is preferably arranged in the groove.
(3) It is preferable that the groove width, which is the radial dimension of the groove, decreases toward the bottom of the groove.

(4) The helical gear is recessed in one end surface of the helical gear and is annular in the axial direction, and is formed in the other end surface of the helical gear. It is preferable to have a third concave portion which is recessed and has an annular shape when viewed from the axial direction.
(5) It is preferable that a plurality of vertical grooves extending along the axial direction are provided at intervals in the circumferential direction on the outer peripheral surface of the boss.

(6) The speed reducer disclosed herein includes the gear structure according to any one of (1) to (5) above, and is housed in the worm housing portion of the gearbox, and transmits the rotation of the power source. and an output gear fixed to the other end face side of the hub of the helical gear.
(7) The output gear has a large-diameter portion in which output teeth are formed on the outer peripheral surface of a shaft portion arranged on the shaft center, and a columnar small-diameter portion having a diameter smaller than that of the shaft portion. The helical gear has an integrally stepped shape, and includes a first fitting portion recessed in the other end surface of the hub and to which the large diameter portion is press-fitted and fixed, and a bottom surface of the first fitting portion. Further, it is preferable to have a second fitting portion which is recessed and into which the small diameter portion is press-fitted and fixed.

(8) A motor unit disclosed herein includes a speed reducer according to (6) or (7) above, and a rotary shaft coupled to the drive shaft that rotates integrally with the worm of the speed reducer, a motor attached to the gearbox.

According to the disclosed gear structure, the helical gear can be prevented from floating or tilted, and the helical gear can be stably supported for rotation.
Further, according to the disclosed speed reducer and motor unit, the rotating state of the helical gear can be stably supported, so that the quality can be improved.

3 is a plan view of the motor unit according to the embodiment; FIG. FIG. 2 is a perspective view showing an exploded part of a speed reducer included in the motor unit of FIG. 1; 3 is an axial cross-sectional view of a helical gear provided in the speed reducer of FIG. 2; FIG. 4 is a perspective view of the helical gear of FIG. 3 as seen from one end side; FIG. FIG. 3 is a cross-sectional view of the gearbox of FIG. 2 taken along line AA of FIG. 1; It is a sectional view explaining an operation of gear structure of an embodiment.

A gear structure, a speed reducer, and a motor unit as embodiments will be described with reference to the drawings. The embodiments shown below are merely examples, and there is no intention to exclude various modifications and application of techniques not explicitly described in the embodiments below. Each configuration of this embodiment can be modified in various ways without departing from the gist thereof. Also, they can be selected or combined as needed.

The gear structure includes a helical gear having teeth on the outer peripheral surface and a gear box that accommodates the helical gear, and is characterized by a sliding structure that supports the helical gear for rotation. The gear structure of this embodiment is incorporated in a speed reducer that reduces the rotational speed of a motor. Furthermore, a motor is combined with this speed reducer to form a motor unit.

[1. composition]
FIG. 1 is a plan view of the motor unit 1 of this embodiment (viewed from the axial direction of the output gear 6 of the speed reducer 3). The motor unit 1 is used, for example, as a drive source for a sliding door closer device or a power window device of a vehicle. The motor unit 1 has a motor 2 (power source) in which a rotor and a stator (not shown) are incorporated in a housing 2A, and a speed reducer 3 that reduces the rotation speed of the motor 2 . The motor 2 of this embodiment is, for example, a DC motor with brushes, and is unitized with the speed reducer 3 by attaching the housing 2A to the gear box 3A of the speed reducer 3 .

FIG. 2 is an exploded perspective view showing a part of the speed reducer 3 in the motor unit 1. As shown in FIG. The speed reducer 3 includes a worm 4 (see FIG. 6) to which the rotation of the motor 2 is transmitted, a helical gear 10 (worm wheel) that meshes with the worm 4, a drive shaft 5 (see FIG. 6) that rotates integrally with the worm 4, and an output. It has an output gear 6 for transmission to the outside and a sealing material (not shown). These elements are built in the gearbox 3A. The speed reducer 3 includes a gear structure 9 characterized by the structure of the portion where the hub 11 (described later) of the helical gear 10 and the boss 32 (described later) of the gear box 3A slide.

As shown in FIG. 2, the gear box 3A is made of resin, for example, and has a worm housing portion 30 that houses the worm 4 and a bottomed tubular helical gear housing portion 31 (housing portion) that houses the helical gear 10. . These two housing portions 30 and 31 communicate with each other at the point where the worm 4 and the helical gear 10 mesh. The worm housing portion 30 extends along the center line S of the drive shaft 5 indicated by the dashed line in FIG. 2 and opens to the surface on which the motor 2 is mounted. The opening is closed when the motor 2 is attached.

The helical gear housing portion 31 includes a substantially circular bottom surface 31a centered on the rotation center C (hereinafter referred to as "axis center C") of the helical gear 10, and a substantially cylindrical wall portion 31e erected from the peripheral edge of the bottom surface 31a. It has a cylindrical storage space surrounded by The helical gear housing portion 31 is closed by attaching a cover 3B (see FIG. 1) to the substantially circular opening 31d. The cover 3B is provided with a circular hole for exposing the output gear 6 to the outside. As shown in FIG. 2, the helical gear housing portion 31 has a cylindrical boss 32 protruding from a bottom surface 31a in the axial direction of the axis C (hereinafter referred to as "the direction of the axis C"). The boss 32 is a portion that rotatably supports the helical gear 10 .

The worm 4 has a drive shaft 5 at its center and is housed in a worm housing portion 30 . A rotating shaft 2B (see FIG. 1) of the motor 2 is coaxially connected to the driving shaft 5, or the driving shaft 5 and the rotating shaft 2B are configured by the same component. rotates together. That is, the worm 4 is rotated by the power of the motor 2 to rotate the helical gear 10 meshing with the worm 4 . Note that the center line S of the drive shaft 5 and the center line of the rotation shaft 2B of the motor 2 are on a straight line, and the center line S of the drive shaft 5 coincides with the center of rotation of the worm 4.

The helical gear 10 is a resin gear formed by injection molding, for example, and is housed in the helical gear housing portion 31 . The helical gear 10 is a helical gear (external gear) having external teeth 13 that mesh with the worm 4, and rotates around an axis C perpendicular to the center line S of the drive shaft 5 (perpendicular at the twist position). As shown in FIGS. 2 to 4, the helical gear 10 includes an annular hub 11 centered on the axis C, a substantially annular rim 12 centered on the axis C, and an outer peripheral surface of the rim 12. and an intermediate portion 14 connecting the hub 11 and the rim 12 . 3 and 4, the helical gear 10 has a first concave portion 11b formed in a substantially cylindrical shape from one end surface 11a of the hub 11 in the axial center C direction. One end surface 11 a of the hub 11 faces the bottom surface 31 a of the helical gear housing portion 31 when the helical gear 10 is housed in the helical gear housing portion 31 .

The gear structure 9 of this embodiment includes the helical gear 10 and the gear box 3A. As shown in FIGS. It protrudes from the position of a virtual plane F (two-dot chain line in the figure) orthogonal to the direction of the straight axis C or to the opening 31 d side of the helical gear accommodating portion 31 from the virtual plane F. In other words, in the present gear structure 9, the annular tip surface of the boss 32 is provided at a position flush with the virtual plane F or at a position protruding from the virtual plane F toward the opening 31d. When the housed helical gear 10 rotates, the outer peripheral surface 32a of the boss 32 slides on the inner peripheral surface 11c of the first concave portion 11b of the hub 11 to support the helical gear 10 . In other words, the outer peripheral surface 32a of the boss 32 and the inner peripheral surface 11c of the first concave portion 11b are sliding surfaces that slide when the helical gear 10 rotates. In the plane 11c) its rotation is supported.

As shown in FIGS. 2, 5 and 6, the helical gear housing portion 31 of the present embodiment has an annular groove portion 31b (hereinafter referred to as "annular groove portion 31b”). The annular groove portion 31b has an annular shape when viewed from the direction of the axis C, and the cross-sectional shape cut in the depth direction (the direction of the axis C) has a groove width that decreases toward the bottom. there is The groove width referred to here is the radial dimension of the annular groove portion 31b. That is, the cross-sectional shape of the annular groove portion 31b preferably includes a trapezoidal shape, a semicircular shape, a semielliptical shape, and the like. The cross-sectional shape of the annular groove portion 31b shown in FIGS. 5 and 6 is a hexagonal shape combining a rectangle and a trapezoid. Due to the annular groove portion 31b, compared to the case where the boss 32 rises vertically from the bottom surface 31a without the annular groove portion 31b, and the case where the boss 32 rises vertically from the bottom surface of the annular groove portion 31b, the boss 32 is Stress concentration at the root portion is suppressed.

As shown in FIGS. 3 and 4, the helical gear 10 of this embodiment has a cylindrical wall portion 11e (hereinafter referred to as "cylindrical wall 11e") that forms the first concave portion 11b. As shown in FIG. 6, the tip of the cylindrical wall 11e is arranged in the annular groove 31b. However, the tip of the cylindrical wall 11e is not in contact with the bottom of the annular groove 31b. As shown in FIGS. 3 and 4, the tip of the cylindrical wall 11e is a portion of the one end face 11a of the hub 11 where the first recess 11b is not formed. It is preferable that the tip of the cylindrical wall 11e is chamfered. By disposing the cylindrical wall 11e of the hub 11 in the annular groove 31b recessed in the bottom surface 31a in this manner, the stability of the posture of the cylindrical wall 11e and the area of the sliding surface are ensured.

The helical gear 10 of the present embodiment includes a second recess 15 formed in one end surface of the helical gear 10 and a second recess 15 formed on one end face of the helical gear 10 at the radially outer side of the hub 11 and the radially inner side of the external teeth 13 (that is, the intermediate portion 14). 14, a third concave portion 16 is provided in the other end surface of the helical gear 10. As shown in FIG. Both the second recessed portion 15 and the third recessed portion 16 have an annular shape when viewed from the axis C direction. The weight of the helical gear 10 can be reduced by these concave portions 15 and 16 . It is preferable that the two recesses 15 and 16 are plane-symmetrical with respect to a plane perpendicular to the axis C. As shown in FIG. In the helical gear 10 of this embodiment, a plurality of ribs are provided in the recesses 15 and 16 at intervals in the circumferential direction to increase rigidity.

Further, in the gear structure 9 of the present embodiment, as shown in FIGS. 2 and 5, a plurality of longitudinal grooves 33 are formed by recessing the outer peripheral surface 32a of the boss 32 radially inward. The plurality of longitudinal grooves 33 each extend in the direction of the axis C and are arranged at intervals in the circumferential direction. Grease for lubrication is applied to the outer peripheral surface 32a of the boss 32, and the plurality of longitudinal grooves 33 function as grease reservoirs. Further, by providing the longitudinal groove 33, it becomes easier to ensure the roundness of the cylindrical outer peripheral surface 32a. In addition, in the helical gear housing portion 31 of the present embodiment, a plurality of ribs are also provided on the inner peripheral surface of the boss 32 at intervals in the circumferential direction to increase the rigidity.

Further, in the helical gear housing portion 31 of the present embodiment, a plurality of protrusions 31c are provided that protrude from the bottom surface 31a outside the annular groove portion 31b in the radial direction. Each projection 31c has an arc shape when viewed from the direction of the axis C, and is intermittently arranged to draw a circle in order to prevent bending during resin molding and to function as a grease reservoir. One end surface 12a of the rim 12 of the helical gear 10 contacts the convex portion 31c.

As shown in FIG. 2, the output gear 6 is a gear that transmits the rotation (power) of the motor 2 to a driven body (not shown). do. The output gear 6 has a large-diameter portion 6b in which output teeth 6d are formed on the outer peripheral surface of a shaft portion 6a arranged on the axis C, and a cylindrical small-diameter portion 6c having a diameter smaller than that of the shaft portion 6a. It is a stepped shape integrally having Parts of the small diameter portion 6c and the large diameter portion 6b are press-fitted to the helical gear 10 and fixed.

That is, as shown in FIGS. 2 and 3, the helical gear 10 includes a first fitting portion 11g recessed in the other end surface 11f of the hub 11 and to which the large-diameter portion 6b is press-fitted and fixed. A second fitting portion 11h is further recessed from the bottom surface of 11g and into which the small-diameter portion 6c is press-fitted and fixed. As shown in FIGS. 3 and 4, in the helical gear 10 of the present embodiment, the portion (bottom portion and peripheral wall portion) forming the second fitting portion 11h protrudes into the first recess portion 11b of the hub 11. A hollow columnar portion that protrudes toward the one end surface 11a is formed on the bottom surface 11d of the first concave portion 11b.

[2. effect]
In the gear structure 9 described above, the boss 32 that slides on the inner peripheral surface 11c of the first concave portion 11b is provided at the position of the virtual plane F or protruding from the virtual plane F. As shown in FIG. The imaginary plane F is an extension of the direction in which the power of the motor 2 is transmitted from the worm 4 to the helical gear 10 (power application direction). In other words, in the gear structure 9 described above, the sliding surfaces (the outer peripheral surface 32a of the boss 32 and the inner peripheral surface 11c of the first concave portion 11b) are present on the extension line of the power application direction to the helical gear 10. . As a result, the helical gear 10 can be prevented from being lifted from the boss 32 and tilted with respect to the boss 32, so that the helical gear 10 can be stably supported for rotation. can be done.

Furthermore, according to the gear structure 9 described above, since the projection length (dimension in the direction of the axis C) of the boss 32 is long, the area of the sliding surface (sliding area) can be increased. As a result, since rattling of the helical gear 10 can be reduced, tilting of the helical gear 10 can be further suppressed, and the helical gear 10 can be stably supported for rotation. Also, it is possible to avoid the occurrence of loss due to contact of the helical gear 10 with the gear box 3A at a location other than the sliding surface.

In the gear structure 9 described above, the annular groove portion 31b is recessed in the root portion of the boss 32, and the tip portion of the cylindrical wall 11c of the hub 11 is disposed in the annular groove portion 31b. The length (sliding length) of the dynamic area in the direction of the axis C can be increased, and tilting of the helical gear 10 can be further prevented. In addition, if the boss 32 that rotationally supports the helical gear 10 is raised vertically from the flat bottom surface 31a, the stress concentration increases. However, the sliding length becomes short. On the other hand, by recessing the bottom surface 31a with the annular groove portion 31b, stress concentration can be avoided while securing the sliding area (sliding length).

In particular, the annular groove portion 31b described above has a cross-sectional shape such that the groove width becomes smaller as it approaches the bottom of the annular groove portion 31b (for example, a trapezoidal shape, a semicircular shape, a semielliptical shape, etc.). Therefore, stress concentration at the root portion of the boss 32 can be further reduced compared to the case where the annular groove portion 31b has a rectangular cross-sectional shape.
In the gear structure 9 described above, since the helical gear 10 is formed with the second concave portion 15 and the third concave portion 16, the weight of the helical gear 10 can be reduced.
Further, since the boss 32 described above has a plurality of vertical grooves 33 formed on its outer peripheral surface 32a, grease applied to the outer peripheral surface 32a, which is a sliding surface, can accumulate in the vertical grooves 33, thereby preventing sliding. Loss can be reduced. In addition, it becomes easier to ensure the circularity of the cylindrical outer peripheral surface 32a of the boss 32 .

According to the speed reducer 3 having the gear structure 9 described above, rattling of the helical gear 10 can be suppressed, so the quality of the speed reducer 3 can be improved.
In particular, in the speed reducer 3 described above, not only the large-diameter portion 6b having the teeth 6d of the output gear 6 but also the cylindrical small-diameter portion 6c are press-fitted into and fixed to the helical gear 10. 6 can be deeply press-fitted (in other words, the press-fitting depth can be secured), and the output gear 6 can be prevented from coming off or tilting. Further, since the cylindrical small-diameter portion 6c of the output gear 6 is press-fitted and fixed to the second fitting portion 11h of the helical gear 10, the accuracy of centering the output gear 6 with respect to the helical gear 10 can be enhanced.
Further, according to the motor unit 1 including the speed reducer 3 described above, the rattling of the helical gear 10 in the speed reducer 3 can be suppressed, so the quality of the motor unit 1 can be improved.

[3. others]
The configurations of the gear structure 9 (the gear box 3A and the helical gear 10), the speed reducer 3, and the motor unit 1 described above are examples, and are not limited to those described above.
For example, only one of the second recessed portion 15 and the third recessed portion 16 of the helical gear 10 described above may be provided, the shape may be different from each other, or both may be omitted. Further, the shape of the bottom surface 31a of the helical gear accommodating portion 31 is not limited to the one described above, and the annular groove portion 31b and the convex portion 31c may be omitted. Note that the various ribs described above may be omitted.

The materials of the helical gear 10 and the gear box 3A are not particularly limited, and they do not have to be made of resin as described above.
The method of fixing the output gear 6 to the helical gear 10 is not limited to press-fitting, and the output gear 6 need not have a stepped shape having a large diameter portion 6b and a small diameter portion 6c.
Further, in the above-described embodiment, the helical gear 10 of the speed reducer 3 that constitutes the motor unit 1 has been described.

Reference Signs List 1 motor unit 2 motor 2B rotary shaft 3 speed reducer 3A gear box 4 worm 5 drive shaft 6 output gear 6a shaft portion 6b large diameter portion 6c small diameter portion 6d teeth 9 gear structure 10 helical gear 11 hub 11a one end surface 11b first concave portion 11c inside Peripheral surface 11e Cylindrical wall 11f Other end surface 11g First fitting portion 11h Second fitting portion 13 External teeth 15 Second concave portion 16 Third concave portion 30 Worm accommodating portion 31 Helical gear accommodating portion (accommodating portion)
31a Bottom surface 31b Annular groove (groove)
31d Opening 32 Boss 32a Outer peripheral surface 33 Vertical groove C Shaft center of helical gear F Virtual plane S Center line of drive shaft

Claims (8)

a helical gear having external teeth that mesh with a worm that rotates integrally with a drive shaft and that rotates around an axis orthogonal to the center line of the drive shaft;
a gear box having a bottomed tubular accommodation portion that accommodates the helical gear,
The helical gear has an annular hub centered on the axis, and a first concave portion recessed in a substantially cylindrical shape from one end surface of the hub in the axial direction of the axis,
The accommodating portion has a bottom surface facing the one end surface when the helical gear is accommodated, and a boss projecting cylindrically from the bottom surface in the axial direction and supporting the helical gear so as to be rotatable,
The boss protrudes at a position of a virtual plane passing through the center line of the drive shaft and perpendicular to the axial direction, or at an opening side of the housing portion from the virtual plane, and is arranged so that when the housed helical gear rotates, , the gear structure, wherein the outer peripheral surface of the boss slides on the inner peripheral surface of the first recess to support the helical gear. The accommodating portion has an annular groove recessed in the bottom surface at the root portion on the radially outer side of the boss,
2. The gear structure according to claim 1, wherein the tip of the cylindrical wall forming the first concave portion of the hub is disposed in the groove portion. 3. The gear structure according to claim 2, wherein the groove width, which is the radial dimension of the groove, decreases toward the bottom of the groove. The helical gear is recessed in one end face of the helical gear, and is recessed in the second end face of the helical gear when viewed from the axial direction. The gear structure according to any one of claims 1 to 3, characterized by having an annular third concave portion when viewed from the axial direction. 5. The apparatus according to any one of claims 1 to 4, characterized in that a plurality of vertical grooves extending along the axial direction are provided on the outer peripheral surface of the boss at intervals in the circumferential direction. gear structure. A gear structure according to any one of claims 1 to 5;
the worm accommodated in the worm accommodating portion of the gearbox and to which rotation of a power source is transmitted;
and an output gear fixed to the other end face side of the hub of the helical gear. The output gear integrally has a large-diameter portion in which output teeth are formed on the outer peripheral surface of a shaft portion arranged on the axial center, and a columnar small-diameter portion having a diameter smaller than that of the shaft portion. It has a stepped shape,
The helical gear includes a first fitting portion recessed in the other end surface of the hub and to which the large diameter portion is press-fitted and fixed, and a small diameter portion recessed further from the bottom surface of the first fitting portion. 7. The speed reducer according to claim 6, further comprising a second fitting portion to which is press-fitted and fixed. a speed reducer according to claim 6 or 7;
and a motor attached to the gear box, the motor unit having a rotary shaft connected to the drive shaft that rotates integrally with the worm of the speed reducer.

Images