JP2020060206A - Gear device - Google Patents

Abstract

To provide a gear device capable of easily attaching a cover to a housing.SOLUTION: A gear device includes a housing 11 which stores a gear, a cover 19 for covering an opening of the housing 11, and a plurality of fastening members 90 for fastening the cover 19 with respect to the housing 11. The cover 19 has a plurality of insertion holes through which the fastening member 90 is inserted, and the housing 11 has a plurality of fastening holes in correspondence with the insertion holes. In at least one set of a plurality of sets constituted by the insertion holes and the fastening holes, a projecting portion 93 is provided in the vicinity of the insertion hole or the fastening hole, and a fitting portion 94 to which the projecting portion 93 is fitted is provided in the vicinity of the other.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a gear device having a gear.

As an example of the gear device, the technique described in Patent Document 1 is known.
The gear device described in Patent Document 1 includes a housing, a gear housed in the housing, and a cover that covers an opening of the housing. The cover is fastened to the housing by a plurality of fastening members.

JP, 2017-227227, A

  By the way, it is preferable that the cover is easily attached to the housing. Then, the gear device which can attach a cover to a housing easily is provided.

  (1) A gear device that solves the above problem includes a housing that accommodates a gear, a cover that covers an opening of the housing, and a plurality of fastening members that fasten the cover to the housing, and the cover includes A plurality of insertion holes through which the fastening member is inserted, the housing has a plurality of fastening holes corresponding to the insertion holes, and at least one of a plurality of sets of the insertion holes and the fastening holes. In the set, a raised portion is provided around one of the insertion hole and the fastening hole, and a fitting portion into which the raised portion fits is provided around the other.

  With this configuration, when the cover is attached to the housing, the cover can be positioned with respect to the housing when the insertion hole of the cover and the fastening hole of the housing are aligned with each other. In this way, the positioning of the cover and the housing in the fastening and the positioning of the cover with respect to the housing can be performed by a series of operations, so that the cover can be easily attached to the housing.

  (2) In the gear device, the raised portion is configured to extend over the entire circumference of a hole in which the raised portion is provided among the insertion hole and the fastening hole, and the fitting portion includes the insertion hole and the fastening hole. The fastening hole is configured so as to cover the entire circumference of the hole in which the fitting portion is provided. With this configuration, positioning can be performed in all directions and the cover can be attached to the housing more easily than in the case where the raised portion and the fitting portion are provided on a part of the entire circumference of the hole.

  (3) In the above gear device, in two sets out of a plurality of sets consisting of the insertion hole and the fastening hole, a raised portion is provided around one of the insertion hole and the fastening hole, and around the other. Is provided with a fitting portion into which the raised portion fits, and a distance between the two sets of two insertion holes having the raised portion and the fitting portion is a plurality of sets including the insertion hole and the fastening hole. Is longer than the distance between any two sets of two insertion holes in the other.

  According to this structure, the cover can be attached to the housing by using two sets of the cover having a longer distance between the insertion holes than any other two sets. In the gear device, the displacement of the cover with respect to the housing can be reduced.

  (4) In the above gear device, two gears that mesh with each other are provided, and the cover can rotate the first support portion that rotatably supports one of the two gears and the other gear. A second support portion that supports the insertion hole and the fastening hole, and in two of a plurality of sets including the insertion hole and the fastening hole, a raised portion is provided around one of the insertion hole and the fastening hole. A fitting portion into which the raised portion fits is provided on the other side, and the two sets having the raised portion and the fitting portion are two of the two when viewed from a direction along the rotation axis of the gear. The gears are arranged on a straight line that perpendicularly intersects the rotation axis of each gear.

  With this configuration, the cover can be accurately attached to the housing at the predetermined position, and the first support portion and the second support portion are set at the predetermined positions with respect to the two gears. Therefore, it is possible to prevent the frictional resistance at the contact portion between the first support portion and one gear and the frictional resistance at the contact portion between the second support portion and the other gear from increasing due to the positional displacement of the cover.

  (5) In the gear device, the fitting portion is provided around the fastening hole, the raised portion is provided around the insertion hole of the cover, and the raised portion is provided in the cover. A recessed portion is provided on a surface opposite to the surface on which the recessed portion is formed, and the recessed portion is configured to accommodate at least a part of a head portion of the fastening member.

  According to this structure, compared with the structure in which the raised portion is provided around the fastening hole of the housing and the fitting portion is provided around the insertion hole of the cover, the fastening member is fastened from the fastening surface of the housing in the axial direction. The protruding length of the member can be shortened.

  According to the above gear device, the cover can be easily attached to the housing.

The top view of a motor unit. The perspective view of a gear device. The exploded perspective view of a gear device. The top view of a gear device. Sectional drawing which follows the VV line of FIG. Sectional drawing which follows the VI-VI line of FIG. The top view of a drive gear. Sectional drawing which follows the VIII-VIII line of FIG. The perspective view of a housing. The top view of a housing. Sectional drawing which follows the XI-XI line of FIG. Sectional drawing which follows the XII-XII line of FIG. The enlarged view of the A section of FIG. The top view of a cover. Sectional drawing which follows the XV-XV line of FIG.

  The gear device is attached to the motor and various actuators. In one example, the gearing is attached to the motor. A motor unit is an example of a device having a gear device.

  FIG. 1 is a plan view of the motor unit 1. For example, the motor unit 1 is attached to a vehicle seat. In one example, the motor unit 1 constitutes a power generation unit of an actuator for changing the inclination angle of the back seat. In another example, the motor unit 1 constitutes a power generation unit of an actuator for moving the back seat up and down. The motor unit 1 includes a motor 2 and a gear device 10. The gear device 10 of the present embodiment reduces the rotation speed of the output shaft of the motor 2.

  FIG. 1 shows an example of the motor unit 1. In this example, the motor 2 is a brushed motor. The motor 2 has a power feeding portion 2a around the output shaft. The gear device 10 is attached to the motor 2 on the power feeding portion 2a side.

  The gear device 10 will be described with reference to FIGS. 2 to 12. 2 is a perspective view of the gear device 10, and FIG. 3 is an exploded perspective view of the gear device 10. FIG. 4 is a plan view of the gear device 10.

  As shown in FIG. 3, the gear device 10 includes a housing 11 that accommodates the gear 12, and a plurality of fastening members 90 that fastens the cover 19 to the housing 11. In the present embodiment, the gear device 10 includes a housing 11, at least one gear 12 housed in the housing 11, a cover 19, and a fastening member 90. The gear device 10 includes, as the gear 12, a worm 13, a worm wheel 14 that interlocks with the worm 13, and a drive gear 15 that interlocks with the worm wheel 14.

The worm 13 is arranged in the housing 11. Specifically, the worm 13 is housed in the third housing portion 53 of the housing 11.
The worm 13 includes a worm gear portion 20, a first end portion 21 provided at one end of the worm gear portion 20, a second end portion 22 provided on the opposite side of the worm gear portion 20 from the first end portion 21, and the worm gear portion 20. And a worm support portion 23 provided between the second end portion 22 and the second end portion 22.

  As shown in FIG. 5, the first end 21 of the worm 13 is supported by the housing 11. The second end 22 of the worm 13 is coupled to the output shaft of the motor 2. A roller 25 is attached to the worm support 23. The worm support portion 23 is rotatably held by the housing 11 via a roller 25. The worm 13 and the roller 25 are retained by a retainer 26 so that the worm 13 and the roller 25 do not come off from the third accommodating portion 53 when accommodated in the third accommodating portion 53 of the housing 11. The worm 13 is coupled to the output shaft so that the worm rotation shaft center CA is along the rotation axis CX of the output shaft of the motor 2.

  As shown in FIG. 3, the worm wheel 14 includes a wheel shaft 30 having a first rotation axis CB, a first gear 34, and a second gear 35. The first gear 34 is provided on the wheel shaft 30 and rotates about the first rotation axis CB. The first gear 34 meshes with the worm 13. The second gear 35 is provided on the wheel shaft 30 and rotates about the first rotation axis CB. The diameter of the second gear 35 is smaller than the diameter of the first gear 34. The wheel shaft 30 has a first end portion 31 and a second end portion 32 (see FIG. 6). The first end 31 is supported by the housing 11. The second end 32 is supported by the cover 19.

  The drive gear 15 includes one or a plurality of gears 12. The drive gear 15 rotates around the second rotation axis CC as the center of rotation. In the present embodiment, the drive gear 15 is configured as a third gear that meshes with the second gear 35.

  As shown in FIG. 6, the drive gear 15 is rotatably supported by the cover 19 and the housing 11. The drive gear 15 is arranged in the space between the cover 19 and the housing 11. The drive gear 15 includes a first surface 15a that intersects with the second rotation axis CC and a first surface 15a on the side opposite to the first surface 15a in the direction along the second rotation axis CC (hereinafter, "second direction DB"). It has two surfaces 15b. The first surface 15 a faces the second bottom surface 67 of the second accommodation portion 52 of the housing 11. The second surface 15b faces the cover 19.

  As shown in FIGS. 7 and 8, the first surface 15a of the drive gear 15 is provided with a recess 16 centered on the second rotation axis CC. The recess 16 is provided radially outside the mounting portion 15c of the drive gear 15. The recess 16 is formed in an annular shape so as to surround the attachment portion 15c. The concave portion 16 has at least one peripheral surface along a cylindrical surface centered on the second rotation axis CC. As in the present embodiment, the recess 16 may be formed in an annular shape. In this case, the recess 16 has an inner peripheral surface 16a and an outer peripheral surface 16b having a diameter larger than that of the inner peripheral surface 16a. The concave portion 16 has a first sliding contact surface 16x that is in sliding contact with a protrusion 80, which will be described later. The first sliding contact surface 16x is formed on one of the inner peripheral surface 16a and the outer peripheral surface 16b of the recess 16. In the embodiment, the first sliding contact surface 16x is provided on the inner peripheral surface 16a of the recess 16.

  The second surface 15b of the drive gear 15 is provided with a convex portion 17 centered on the second rotation axis CC. The convex portion 17 has at least one peripheral surface along a cylindrical surface centered on the second rotation axis CC. For example, the convex portion 17 is provided radially outside the mounting portion 15c of the drive gear 15. The convex portion 17 is formed in an annular shape so as to surround the mounting portion 15c. The convex portion 17 has an inner peripheral surface 17a and an outer peripheral surface 17b having a diameter larger than the diameter of the inner peripheral surface 17a. The convex portion 17 has a second sliding contact surface 17x that is in sliding contact with a support portion 85 described later. The second sliding contact surface 17x is formed on one of the inner peripheral surface 17a and the outer peripheral surface 17b of the convex portion 17 of the drive gear 15 which is opposite to one surface of the concave portion 16 on which the first sliding contact surface 16x is formed. Composed. In the present embodiment, the first sliding contact surface 16x is provided on the inner peripheral surface 16a of the concave portion 16, and the second sliding contact surface 17x is provided on the outer peripheral surface 17b of the convex portion 17. Unlike the present embodiment, the first sliding contact surface 16x may be provided on the outer peripheral surface 16b of the concave portion 16 and the second sliding contact surface 17x may be provided on the inner peripheral surface 17a of the convex portion 17.

  Preferably, the inner peripheral surface 17a and the outer peripheral surface 17b of the convex portion 17 and the inner peripheral surface 16a and the outer peripheral surface 16b of the concave portion 16 overlap each other when seen through from the second direction DB. Such a configuration in which the convex portion 17 and the concave portion 16 overlap can be formed by pressing a plate-shaped member.

  An attachment portion 15c to which the power transmission member 60 is attached is provided at the center of the drive gear 15. The mounting portion 15c has a shaft hole 15d having a second rotation shaft center CC. The power transmission member 60 is coupled to the shaft hole 15d. The power transmission member 60 is a member for transmitting power to a device other than the gear device 10. The power transmission member 60 is attached to the drive gear 15 so as to rotate integrally with the drive gear 15. For example, the shaft hole 15d is configured in a non-circular shape, for example, a quadrangle or a hexagon when viewed from the second direction DB. The cross section of the power transmission member 60 has a shape that matches the shape of the shaft hole 15d.

  As shown in FIG. 6, the worm wheel 14 and the drive gear 15 are arranged such that the first rotation axis CB of the wheel shaft 30 and the second rotation axis CC of the drive gear 15 are parallel to each other. . The drive gear 15 partially overlaps the worm wheel 14 when viewed from the second direction DB. Specifically, a part of the drive gear 15 overlaps the first gear 34 when viewed from the second direction DB.

An example of the housing 11 will be described with reference to FIGS. 5, 6, and 9 to 12. 11 is a sectional view taken along the line XI-XI of FIG.
The housing 11 accommodates the worm wheel 14, the drive gear 15, and the worm 13.

  As shown in FIG. 9, the housing 11 includes a first accommodating portion 51 that accommodates the worm wheel 14, a second accommodating portion 52 that accommodates at least a part of the drive gear 15, and a third accommodating portion that accommodates the worm 13. And 53.

  Preferably, the housing 11 further includes a motor mounting portion 54. For example, when the motor 2 is a brushed motor, the motor mounting portion 54 accommodates the power feeding portion 2a including a commutator and a brush. The housing 11 is fixed to the motor 2 by fastening the motor mounting portion 54 to the power feeding portion 2a of the motor 2 with the fastening member while the power feeding portion 2a of the motor 2 is accommodated in the motor mounting portion 54.

  As shown in FIGS. 6 and 9, the first housing portion 51 includes a first bottom wall 61 and a first peripheral wall 62. In the first accommodating portion 51, an end portion on the opposite side of the first bottom wall 61 in a direction along the first rotation axis CB (hereinafter, “first direction DA”) is opened to form a first opening portion 51a. To do. The first opening 51a is sized so that the first gear 34 can be inserted therein.

  The first peripheral wall 62 is configured in a tubular shape so as to face the tooth surface of the first gear 34 and the tooth surface of the second gear 35. The first bottom wall 61 has a first bottom surface 63 that faces the first gear 34 (see FIG. 6). A first wheel bearing 64 that receives the first end 31 of the wheel shaft 30 is provided on the first bottom wall 61. The first wheel bearing 64 has an insertion hole 64a through which the first end 31 of the wheel shaft 30 is inserted.

  As shown in FIGS. 9 to 11, the second housing portion 52 includes a second bottom wall 65 and a second peripheral wall 66. In the second accommodating portion 52, an end portion on the opposite side of the second bottom wall 65 in the second direction DB is open to form a second opening portion 52a. The second opening 52a is sized so that the drive gear 15 can be inserted therein. The 1st opening part 51a and the 2nd opening part 52a are connected. The opening 18 of the housing 11 is configured by the first opening 51a and the second opening 52a.

  As shown in FIG. 10, the second bottom wall 65 has a second circle centered on the first rotation axis CB and a first circle centered on the second rotation axis CC as viewed in the second direction DB. And the first circle are overlapped with each other to form a cutout shape.

  The second bottom wall 65 has a second bottom surface 67 that faces the drive gear 15 (see FIG. 6). The second peripheral wall 66 is configured to face the tooth surface of the drive gear 15. A portion of the first peripheral wall 62 that enters the second peripheral wall 66 is cut out. A portion of the second peripheral wall 66 that is inside the first peripheral wall 62 is cut out. The first accommodating portion 51 and the second accommodating portion 52 are connected to each other at a cutout portion (hereinafter, “cutout portion 59”) of the first peripheral wall 62 and the second peripheral wall 66. A part of the drive gear 15 protrudes from the cutout portion 59 toward the first accommodating portion 51 and meshes with the second gear 35.

  As shown in FIG. 6, the second bottom surface 67 is arranged closer to the second gear 35 than the facing surface 34a of the first gear 34 in the first direction DA. The facing surface 34 a of the first gear 34 is a surface facing the drive gear 15. This prevents the drive gear 15 from interfering with the first gear 34. An insertion hole 68 through which the power transmission member 60 is inserted is provided in the second bottom wall 65.

As shown in FIGS. 10 and 12, the third accommodating portion 53 is provided so as to be in contact with the first peripheral wall 62 of the first accommodating portion 51.
The third accommodating portion 53 is connected to the first accommodating portion 51 via the communication portion 70 (see FIG. 12). The worm 13 is exposed from the communication portion 70 to the first accommodation portion 51 side and meshes with the first gear 34. The third accommodating portion 53 has a worm opening 71 that opens in a direction along the worm rotation axis CA (see FIG. 5). When the housing 11 is provided with the motor mounting portion 54 as in the present embodiment, the worm opening 71 is connected to the motor mounting portion 54. A bearing 72 that receives the worm 13 is provided on the third accommodation portion 53 on the side opposite to the worm opening 71 in the direction along the worm rotation axis CA. The bearing 72 is provided with a bearing member 72 a that receives the first end 21 of the worm 13.

  As shown in FIGS. 2 and 3, the cover 19 covers the opening 18 of the housing 11. The cover 19 is attached to the housing 11 by the fastening member 90. The cover 19 has a first cover portion 74 that covers the first opening 51 a of the first housing portion 51 and a second cover portion 75 that covers the second opening 52 a of the second housing portion 52. The first cover portion 74 is provided with a second wheel bearing 76 that receives the second end 32 of the wheel shaft 30 (see FIG. 6). The second wheel bearing 76 is composed of, for example, a bush 76a. The first cover portion 74 is provided with a bush mounting hole 79 into which the bush 76a is mounted. The second cover part 75 is provided with a support part 85 which will be described later and is in contact with the drive gear 15.

With reference to FIG. 13, a structure for rotatably supporting the drive gear 15 and its operation will be described.
The drive gear 15 is arranged between the cover 19 and the housing 11 in the second rotation axis CC direction. The first surface 15a of the drive gear 15 is in sliding contact with the housing 11, and the second surface 15b is in sliding contact with the cover 19.

  One of the housing 11 and the cover 19 has a protrusion 80. Specifically, one of the housing 11 and the cover 19 that faces the recess 16 of the drive gear 15 has a protrusion 80.

  The protrusion 80 protrudes toward the drive gear 15. The protrusion 80 has a central axis CD along the second rotational axis CC. The protrusion 80 has at least one peripheral surface along a cylindrical surface centered on the central axis CD. As in the present embodiment, the protrusion 80 may be formed in an annular shape. The protrusion 80 is configured to enter the recess 16 of the drive gear 15. The peripheral surface of the protrusion 80 is in sliding contact with the peripheral surface (the inner peripheral surface 16a or the outer peripheral surface 16b) of the recess 16 of the drive gear 15.

  In the present embodiment, an annular protrusion 80 is provided on the second bottom surface 67 of the second bottom wall 65 of the housing 11. The protrusion 80 has an inner peripheral surface 80a and an outer peripheral surface 80b. The inner peripheral surface 80a of the protruding portion 80 is in sliding contact with the inner peripheral surface 16a of the recess 16 of the drive gear 15 (hereinafter referred to as "inner sliding contact"). Further, the outer peripheral surface 80b of the protruding portion 80 is in sliding contact with the outer peripheral surface 16b of the recess 16 of the drive gear 15 (hereinafter referred to as outer sliding contact). Preferably, the protrusion 80 and the recess 16 are configured such that one of the inner sliding contact and the outer sliding contact has a higher frequency of sliding contact. At least one of the inner peripheral surface 80a and the outer peripheral surface 80b of the protrusion 80 is formed into a cylindrical surface. Further, at least one of the inner peripheral surface 16a and the outer peripheral surface 16b of the recess 16 is formed into a cylindrical surface. In the case of inward sliding contact, the outer peripheral surface 80b of the protruding portion 80 and the outer peripheral surface 16b of the drive gear 15 do not have to be accurately configured as cylindrical surfaces. For example, in the arrangement of the first accommodating portion 51 and the second accommodating portion 52, the first accommodating portion 51 and the second accommodating portion 52 are arranged so that the first accommodating portion 51 interferes with the outer peripheral surface 80b of the projecting portion 80. You may approach. In this case, a concave surface 80c is formed on the outer peripheral surface 80b of the protrusion 80. The concave surface 80c constitutes a part of the inner peripheral surface of the first peripheral wall 62 of the first accommodating portion 51 (see FIG. 9). In the present embodiment, the first sliding contact surface 16x, which is in sliding contact with the protruding portion 80, is formed on the inner peripheral surface 16a of the recess 16 of the drive gear 15 so that the frequency of the inner sliding contact increases.

  The housing 11 and the cover 19 that are not provided with the protrusion 80 have a support portion 85 that rotatably supports the drive gear 15. Specifically, one of the housing 11 and the cover 19 that faces the convex portion 17 of the drive gear 15 in the radial direction has the support portion 85.

  The support portion 85 is configured to come into contact with the convex portion 17 of the drive gear 15. The support portion 85 stabilizes the rotation of the drive gear 15 by coming into contact with the convex portion 17 of the drive gear 15. The support portion 85 has a central axis CE along the second rotation axis CC. The supporting portion 85 has at least one peripheral surface along a cylindrical surface centered on the second rotation axis CC. The supporting portion 85 is in sliding contact with the peripheral surface (the inner peripheral surface 17a or the outer peripheral surface 17b) of the convex portion 17 of the drive gear 15.

  In the present embodiment, the support portion 85 is provided in the second cover portion 75 of the cover 19 at the periphery of the insertion hole 77 through which the power transmission member 60 is inserted. For example, the support portion 85 is configured as a peripheral wall 86 along the edge of the insertion hole 77. In the present embodiment, the inner peripheral surface 86a of the peripheral wall 86 is in sliding contact with the outer peripheral surface 17b of the convex portion 17 of the drive gear 15. Therefore, in the present embodiment, the outer peripheral surface 17b of the convex portion 17 of the drive gear 15 is formed with the second sliding contact surface 17x that is in sliding contact with the support portion 85.

The fastening structure of the cover 19 and its action will be described with reference to FIGS. 10, 11, 14 and 15.
The cover 19 has a plurality of insertion holes 91 through which the fastening members 90 are inserted. The housing 11 has a plurality of fastening holes 92 corresponding to the insertion holes 91. In this embodiment, the cover 19 is provided with four insertion holes 91. The housing 11 is provided with four fastening holes 92. In at least one set of the plurality of sets including the insertion hole 91 of the cover 19 and the fastening hole 92 of the housing 11, a raised portion 93 is provided around one of the insertion hole 91 and the fastening hole 92, and is provided around the other. A fitting portion 94 into which the raised portion 93 is fitted is provided. In the following description, one set provided with the raised portion 93 and the fitting portion 94 is referred to as a “predetermined set”.

  In the present embodiment, the raised portion 93 and the fitting portion 94 are provided in two sets out of a plurality of sets including the insertion hole 91 and the fastening hole 92. Specifically, the raised portion 93 is provided around the two insertion holes 91 of the cover 19. The raised portion 93 projects toward the housing 11 side. On the other hand, a fitting portion 94 into which the raised portion 93 is fitted is provided in each of the two fastening holes 92 of the housing 11 (see FIG. 11). Specifically, the raised portion 93 of the cover 19 is configured so as to cover the entire circumference of the insertion hole 91. The fitting portion 94 of the housing 11 is configured to extend over the entire circumference of the fastening hole 92. Further, the cover 19 is provided with a depression 95 on the surface opposite to the surface on which the raised portion 93 is provided. The depressed portion 95 is configured so that at least a part of the head 90a of the fastening member 90 is accommodated (see FIG. 6).

  Preferably, the distance between the two sets provided with the raised portion 93 and the fitting portion 94 is longer than the distance between any two other sets selectable from the plurality of sets of the insertion hole 91 and the fastening hole 92. . The distance between the two sets is defined as the distance between the two insertion holes 91 in the cover 19.

  As shown in FIGS. 10 and 14, more preferably, the two sets including the predetermined one set are the first rotation shaft of the worm wheel 14 when viewed from the direction along the first rotation shaft center CB of the worm wheel 14. It is arranged on a straight line LX that intersects perpendicularly with the center CB and the second rotation axis center CC of the drive gear 15.

  In the present embodiment, the raised portion 93 and the fitting portion 94 are provided in each of the two sets arranged on the straight line LX. In the housing 11, the two fitting portions 94 are arranged on a straight line LXA that perpendicularly intersects the first rotation axis CB and the second rotation axis CC of the housing 11 (see FIG. 10). In the cover 19, the two raised portions 93 are arranged on a straight line LXB that perpendicularly intersects the first rotation axis CB and the second rotation axis CC of the cover 19 (see FIG. 14).

  One of the two sets is a reference for fastening the cover 19, and the other is a quasi-reference. The dimensions of the housing 11 and the cover 19 are set with the center of the reference hole as the origin of dimension. In this embodiment, in FIGS. 10 and 14, the hole on the right side is the reference and the hole on the left side is the quasi-reference.

  In one set as a reference, a circular raised portion 93 having the same center as the center of the insertion hole 91 is provided around the insertion hole 91 of the cover 19. In one set as a reference, a circular fitting portion 94 having the same center as the center of the fastening hole 92 is provided around the fastening hole 92 of the housing 11. The diameter of the fitting portion 94 is slightly larger than the diameter of the raised portion 93.

  A circular raised portion 93 having the same center as the center of the insertion hole 91 is provided around the insertion hole 91 of the cover 19 for one set that is a quasi-reference. An elliptic fitting portion 94 extending along the straight line LX is provided around the fastening hole 92 of the housing 11 for one set that is a quasi-reference. The width of the fitting portion 94 in the lateral direction is slightly larger than the diameter of the raised portion 93. With this configuration, the cover 19 is positioned at a predetermined position in the rotation direction with the center of the insertion hole 91 as the rotation center. Further, the straight line LXB of the cover 19 and the straight line LXA of the housing 11 coincide with each other, and the deviation between the straight line LXA and the straight line LXB is suppressed. As a result, the rotation center of the drive gear 15 and the rotation center of the worm wheel 14 are prevented from being twisted, and the reduction in power transmission efficiency can be suppressed.

  When the cover 19 is attached to the housing 11, of the four sets, the reference set is temporarily fastened by the fastening member 90. At this time, the cover 19 is in a state of being rotatable about the fastening member 90 inserted into the reference insertion hole 91 as an axis. Next, the semi-standard set is temporarily fastened by the fastening member 90. Then, the remaining two sets are temporarily fastened by the fastening member 90. Then, the fastening members 90 are finally fastened in the order of the reference set, the semi-reference set, and the remaining set.

The effects of this embodiment will be described.
(1) In the gear device 10, the cover 19 has a plurality of insertion holes 91 through which the fastening members 90 are inserted. The housing 11 has a plurality of fastening holes 92 corresponding to the insertion holes 91. In at least one set of the plurality of sets including the insertion hole 91 and the fastening hole 92, a raised portion 93 is provided around one of the insertion hole 91 and the fastening hole 92, and a raised portion 93 is provided around the other. A fitting portion 94 into which is fitted is provided.

  With this configuration, when the cover 19 is attached to the housing 11, the cover 19 can be positioned with respect to the housing 11 when the insertion hole 91 of the cover 19 and the fastening hole 92 of the housing 11 are aligned with each other. In this way, since the positioning of the cover 19 and the housing 11 in the fastening and the positioning of the cover 19 with respect to the housing 11 can be performed by a series of operations, the cover 19 can be easily attached to the housing 11.

  (2) Preferably, the raised portion 93 is configured so as to cover the entire circumference of the insertion hole 91 and the fastening hole 92 in which the raised portion 93 is provided. In addition, the fitting portion 94 is configured so as to cover the entire circumference of the insertion hole 91 and the fastening hole 92 in which the fitting portion 94 is provided.

  With this configuration, positioning can be performed in all directions and the cover 19 can be attached to the housing 11 more easily than in the case where the raised portion 93 and the fitting portion 94 are provided on a part of the entire circumference of the hole.

  (3) In two sets out of a plurality of sets consisting of the insertion hole 91 and the fastening hole 92, the raised portion 93 is provided around one of the insertion hole 91 and the fastening hole 92, and is fitted around the other. A section 94 is provided. The distance between the two sets of two insertion holes 91 having the raised portion 93 and the fitting portion 94 is determined by the distance between the two insertion holes 91 of any two sets of the plurality of the insertion holes 91 and the fastening holes 92. Longer than the distance.

  According to this structure, the cover 19 can be attached to the housing 11 by using two sets of the cover 19 having a longer distance between the insertion holes than any other two sets. In the gear device, the displacement of the cover with respect to the housing can be reduced.

  (4) The cover 19 includes a second wheel bearing 76 (first support portion) that rotatably supports the wheel shaft 30 of the worm wheel 14, and a support portion 85 (second support portion) that rotatably supports the drive gear 15. ) And. In two of a plurality of sets including the insertion hole 91 and the fastening hole 92, a raised portion 93 is provided around one of the insertion hole 91 and the fastening hole 92, and a fitting portion 94 is provided around the other. It is provided. When viewed from a direction along the first rotation axis CB of the worm wheel 14, the two sets having the raised portion 93 and the fitting portion 94 have the first rotation axis CB and the second rotation axis CB of the worm wheel 14 and the drive gear 15, respectively. It is arranged on a straight line LX that intersects perpendicularly with the axis CC.

  According to this configuration, the cover 19 can be accurately attached to the housing 11 at a predetermined position, and the second wheel bearing 76 (first support portion) and the support portion can be attached to the wheel shaft 30 of the worm wheel 14 and the drive gear 15. 85 (second support portion) is set at a predetermined position. Therefore, the frictional resistance in the contact portion between the second wheel bearing 76 of the cover 19 and the wheel shaft 30 of the worm wheel 14 and the frictional resistance in the contact portion between the supporting portion 85 (second supporting portion) of the cover 19 and the drive gear 15. However, it is possible to suppress the increase due to the displacement of the cover 19.

  (5) Preferably, the fitting portion 94 of the housing 11 is provided around the fastening hole 92. The raised portion 93 is provided around the insertion hole 91 of the cover 19. A depression 95 is provided on the surface of the cover 19 opposite to the surface on which the raised portion 93 is provided. The depressed portion 95 is configured to accommodate at least a part of the head portion 90a of the fastening member 90.

  According to this configuration, in comparison with the structure in which the raised portion 93 is provided around the fastening hole 92 of the housing 11 and the fitting portion 94 is provided around the insertion hole 91 of the cover 19, in the axial direction of the fastening member 90. The protruding length of the fastening member 90 from the fastening surface 96 of the housing 11 can be shortened (see FIG. 6).

<Other embodiments>
The above embodiment is not limited to the above configuration example. The above embodiment can be modified as follows. In the following modifications, configurations that are substantially the same as those of the above-described embodiment will be described with the same reference numerals as those of the above-described embodiment.

In the fastening structure of the cover 19, the raised portion 93 may be provided on the housing 11 and the fitting portion 94 may be provided on the cover 19.
The structure of the raised portion 93 is not limited to the example of the present embodiment for one set that is used as a reference for fastening the cover 19. The raised portion 93 has at least one circumferential surface that fits into the fitting portion 94. The raised portion 93 may have a ring shape.

  -Two sets provided with the raised portion 93 and the fitting portion 94 for the fastening holes may be arranged as follows. Two points are selected such that the distance between the two points is the longest on the outer circumference of the cover 19, and the two sets of two insertion holes 91 are arranged in the vicinity of these two points. The two sets of fastening holes 92 are provided in the housing 11 at positions corresponding to the two insertion holes 91 thus provided.

CA ... Worm rotation axis, CB ... First rotation axis, CC ... Second rotation axis, CD ... Center axis, CE ... Center axis, CX ... Rotation axis, DA ... First direction, DB ... Second direction, LX ... Straight line, LXA ... Straight line, LXB ... Straight line, 1 ... Motor unit, 2 ... Motor, 2a ... Power feeding section, 10 ... Gear device, 11 ... Housing, 12 ... Gear, 13 ... Worm, 14 ... Worm wheel, 15 ... Drive gear, 15a ... 1st surface, 15b ... 2nd surface, 15c ... Attachment part, 15d ... Shaft hole, 16 ... Recessed part, 16a ... Inner peripheral surface, 16b ... Outer peripheral surface, 16x ... 1st sliding contact surface, 17 ... Convex part, 17a ... Inner peripheral surface, 17b ... Outer peripheral surface, 17x ... Second sliding contact surface, 18 ... Opening part, 19 ... Cover, 20 ... Worm gear part, 21 ... First end part, 22 ... Second end part, 23 ... Worm support, 25 ... Roller, 26 ... Retaining, 30 ... Wheel shaft, 1 ... 1st end part, 32 ... 2nd end part, 34 ... 1st gear, 34a ... Opposed surface, 35 ... 2nd gear, 51 ... 1st accommodating part, 51a ... 1st opening part, 52 ... 2nd accommodating Portion 52a ... second opening portion 53 ... third accommodating portion 54 ... motor mounting portion 59 ... notch portion 60 ... power transmission member 61 ... first bottom wall 62 ... first peripheral wall 63 ... first Bottom surface, 64 ... First wheel bearing, 64a ... Insertion hole, 65 ... Second bottom wall, 66 ... Second peripheral wall, 67 ... Second bottom surface, 68 ... Insertion hole, 70 ... Communication portion, 71 ... Worm opening portion, 72 ... Bearing, 72a ... Bearing member, 74 ... First cover part, 75 ... Second cover part, 76 ... Second wheel bearing, 76a ... Bushing, 77 ... Insertion hole, 79 ... Bush mounting hole, 80 ... Projection part, 80a ... inner peripheral surface, 80b ... outer peripheral surface, 80c ... concave surface, 85 ... supporting portion, 86 ... peripheral wall, 86a ... inner peripheral surface, 9 ... fastening member, 90a ... head 91 ... insertion holes, 92 ... fastening hole, 93 ... ridge, 94 ... engaging portion, 95 ... depression, 96 ... fastening surface.

Claims (5)

A housing for housing the gear,
A cover for covering the opening of the housing,
A plurality of fastening members for fastening the cover to the housing,
The cover has a plurality of insertion holes through which the fastening member is inserted,
The housing has a plurality of fastening holes corresponding to the insertion holes,
In at least one set of the plurality of sets including the insertion hole and the fastening hole, a raised portion is provided around one of the insertion hole and the fastening hole, and the raised portion is provided around the other. A gear device provided with a fitting portion to be fitted. The raised portion is configured so as to cover the entire circumference of a hole in which the raised portion is provided among the insertion hole and the fastening hole,
The gear device according to claim 1, wherein the fitting portion is configured so as to cover the entire circumference of a hole in which the fitting portion is provided among the insertion hole and the fastening hole. In two of a plurality of sets including the insertion hole and the fastening hole, a protrusion is provided around one of the insertion hole and the fastening hole, and the protrusion is fitted around the other. A joint is provided,
The distance between the two insertion holes of the two sets having the raised portion and the fitting portion is determined by the distance between the two insertion holes of any two sets of the insertion hole and the fastening hole. The gear device according to claim 1 or 2, which is longer than the distance. With two gears that mesh with each other,
The cover has a first support portion that rotatably supports one of the two gears, and a second support portion that rotatably supports the other gear,
In two of a plurality of sets including the insertion hole and the fastening hole, a protrusion is provided around one of the insertion hole and the fastening hole, and the protrusion is fitted around the other. A joint is provided,
The two sets having the raised portion and the fitting portion are arranged on a straight line perpendicularly intersecting the rotation axis of each of the two gears when viewed from a direction along the rotation axis of the gear. Item 5. The gear device according to any one of items 1 to 3. The fitting portion is provided around the fastening hole,
The raised portion is provided around the insertion hole of the cover,
A recess is provided on the surface of the cover opposite to the surface on which the protrusion is provided, and the recess is configured to accommodate at least a part of the head of the fastening member. The gear device according to any one of claims 1 to 4.