Vehicle seat gearbox

Abstract

To provide a gear box for a vehicle seat which can suppress increase of sliding friction at an end part of a shaft and rattling of the shaft.SOLUTION: A gear box is used for a movable mechanism of a vehicle seat. The gear box comprises: a shaft; a housing which accommodates a gear and a rotary bearing and includes a female screw part; a thrust bearing including an action part which contacts with an end part of the shaft, a male screw part which is screwed together with the female screw part, and a part to be engaged which is arranged at a position where the male screw part is sandwiched between the action part and the part to be engaged; and a cap including an engagement part which is engaged with the part to be engaged of the thrust bearing and a retainer which restricts departure of the thrust bearing from the housing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a gearbox for a vehicle seat. [Background technology]

[0002] A vehicle seat installed in an automobile or the like includes a gearbox as a drive source for displacing a portion of the seat. The gearbox has a shaft for transmitting drive power from a motor, a gear, and a thrust bearing.

[0003] When a shaft rotates, it rattles along the axial direction. To suppress noise caused by this rattle, a structure is known in which the thrust bearing is pressed against the tip of the shaft by adjusting its position with a screw (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-330027 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned screw-based thrust bearing adjustment mechanism, the tightening torque of the screw must be large to prevent the screw from loosening under thrust load. This increases the pressing force of the thrust bearing against the shaft (i.e., sliding resistance), and increases the loss of driving force due to friction.

[0006] An object of one aspect of the present disclosure is to provide a gearbox for a vehicle seat that can suppress rattle of the shaft while suppressing an increase in sliding resistance at the end of the shaft. [Means for solving the problem]

[0007] One aspect of the present disclosure is a vehicle seat gear box (1) used in a movable mechanism (15, 16, 17, 18) configured to displace a portion of a vehicle seat (10). The vehicle seat gear box (1) includes a shaft (2), a gear (3A) fixed to the shaft (2), a rotary bearing (4) that rotatably supports the shaft (2), and a housing (5) that houses the shaft (2), the gear (3A), and the rotary bearing (4) and has a female thread portion (521).

[0008] The vehicle seat gearbox (1) further includes a thrust bearing (7) having an operating portion (71) that contacts the end of the shaft (2), a male thread portion (72) that is threaded onto the female thread portion (521), and an engaged portion (73) that is positioned to sandwich the male thread portion (72) together with the operating portion (71) in the axial direction of the shaft (2), an engaging portion (81) that engages with the engaged portion (73) of the thrust bearing (7), and a cap (8) that prevents the thrust bearing (7) from coming off the housing (5). The retaining portion (82) is attached to the housing (5) or inserted into the thrust bearing (7) so as to press the thrust bearing (7) against the housing (5).

[0009] With this configuration, the cap 8 restricts the movement of the thrust bearing 7 in the axial direction of the shaft 2. This minimizes the fastening torque between the male thread portion 72 of the thrust bearing 7 and the female thread portion 521 of the housing 5. This prevents an increase in sliding resistance at the end of the shaft 2 and also reduces rattle of the shaft 2.

[0010] In one aspect of the present disclosure, the retaining portion 82 may be attached to the housing 5. The cap 8 may have a cap anti-rotation portion 83 that restricts rotation of the engaging portion 81 and the retaining portion 82 about the central axis of the shaft 2 relative to the housing 5. With this configuration, restricting rotation of the thrust bearing 7 relative to the housing 5 suppresses loosening of the fastening between the male thread portion 72 and the female thread portion 521.

[0011] In one aspect of the present disclosure, the retaining portion 82 may be a cylindrical body inserted into the housing 5. The cap anti-rotation portion 83 may be a serration extending from the outer circumferential surface of the retaining portion 82 and having a plurality of teeth arranged in parallel along the circumferential direction of the retaining portion 82. This configuration can enhance the anti-rotation effect of the cap 8 relative to the housing 5 with a relatively simple configuration.

[0012] In one aspect of the present disclosure, the housing (5) may have a cylindrical shaft accommodating portion (51) and a cylindrical holder (52) disposed inside the shaft accommodating portion (51). The holder (52) may have a female thread portion (521) and a bearing holder portion (522) that holds the rotary bearing (4). With this configuration, the rotary bearing (4) and the female thread portion (521) can be disposed inside the housing (5) by inserting the holder (52) into the shaft accommodating portion (51).

[0013] In one aspect of the present disclosure, the holder 52 may have a holder anti-rotation portion 523 that restricts rotation of the female thread portion 521 and the bearing holding portion 522 about the central axis of the shaft 2 relative to the shaft accommodating portion 51. The shaft accommodating portion 51 may have a restricting portion 511 that restricts movement of the action portion 71 of the holder 52 in the direction in which the thrust load is transmitted. With this configuration, the rotation and movement of the holder 52 are restricted, thereby suppressing loosening of the fastening between the male thread portion 72 and the female thread portion 521.

[0014] In one aspect of the present disclosure, the engaging portion (81) may have a cylindrical first base portion (811) into which the engaged portion (73) of the thrust bearing (7) is inserted, and a first uneven portion (812) provided on the inner circumferential surface of the first base portion (811). With this configuration, the engagement strength of the cap (8) with the thrust bearing (7) can be increased with a relatively simple configuration.

[0015] In one aspect of the present disclosure, the retaining portion (82) may have a cylindrical second base portion (821) that is inserted into the housing (5) and a second uneven portion (822) that is provided on the outer peripheral surface of the second base portion (821). With this configuration, the effect of preventing the cap (8) from coming off the housing (5) can be improved with a relatively simple configuration.

[0016] Note that the symbols in the parentheses above are examples showing the correspondence with the specific configurations, etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations, etc. shown by the symbols in the parentheses above. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic perspective view of a vehicle seat according to an embodiment. [Figure 2] FIG. 2 is a schematic perspective view of a gearbox in the vehicle seat of FIG. [Figure 3] FIG. 3 is a schematic perspective view of the internal structure of the gearbox of FIG. [Figure 4] FIG. 4 is a schematic cross-sectional end view taken along line IV-IV in FIG. [Figure 5] 5A is a schematic cross-sectional view taken along line VA-VA in FIG. 4, and FIG. 5B is a schematic cross-sectional view taken along line VB-VB in FIG. [Figure 6] 6A and 6B are schematic perspective views of a thrust bearing in the gearbox of FIG. 2. [Figure 7] 7A and 7B are schematic perspective views of the cap in the gearbox of FIG. 2. FIG. [Figure 8] FIG. 8 is a schematic cutaway end view of a gearbox in an embodiment different from that of FIG. [Figure 9] 9A is a schematic cross-sectional end view of a gearbox in an embodiment different from that of FIG. 4, and FIG. 9B is a schematic view showing an example of a procedure for attaching the thrust bearing and cap of FIG. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings. [1. First embodiment] [1-1.Configuration] The vehicle seat 10 shown in FIG. 1 includes a seat cushion 11, a seat back 12, a cushion frame 13, a back frame 14, a reclining device 15, a sliding device 16, a lifter device 17, and a tilt device 18.

[0019] The vehicle seat 10 is used as a seat for automobiles such as passenger cars, as well as for railway vehicles, ships, aircraft, etc. The seat cushion 11 is a portion that supports the buttocks and other parts of the seated occupant. The seat back 12 is a portion that supports the back of the seated occupant. The cushion frame 13 supports the seat cushion 11. The back frame 14 supports the seat back 12.

[0020] The reclining device 15 is a known movable mechanism that swings the back frame 14 in the front-rear direction of the seat relative to the cushion frame 13. The slide device 16 is a known movable mechanism that supports the cushion frame 13 so that the cushion frame 13 can slide in the front-rear direction of the seat.

[0021] The lifter device 17 is a known movable mechanism that raises and lowers the cushion frame 13. The tilt device 18 is a known movable mechanism that swings the front end of the cushion frame 13 up and down.

[0022] The reclining device 15, the sliding device 16, the lifter device 17, and the tilt device 18 each have a gear box 1 shown in FIG. 2 as a drive source.

[0023] <Gearbox> As shown in FIGS. 2 and 3, the gearbox 1 includes a shaft 2, a first gear 3A, a second gear 3B, a rotary bearing 4, a housing 5, an actuator 6, a thrust bearing 7, and a cap 8.

[0024] In this embodiment, the axis parallel to the central axis of the shaft 2 (i.e., the rotational axis of the first gear 3A) is the X-axis, the axis parallel to the rotational axis of the second gear 3B is the Y-axis, and the axis perpendicular to both the X-axis and the Y-axis is the Z-axis.

[0025] <Shaft> The shaft 2 shown in FIG. 3 is connected to an actuator 6 and rotates about its axis by the driving force of the actuator 6.

[0026] <First Gear> The first gear 3A is fixed to the shaft 2 by, for example, press-fitting. In this embodiment, the first gear 3A is a worm (i.e., a screw gear) that meshes with the second gear 3B. However, the first gear 3A is not limited to a worm and may be, for example, a helical gear.

[0027] <Second Gear> The second gear 3B is connected to the first gear 3A and rotates by the driving force transmitted from the first gear 3A. The rotation axis of the second gear 3B intersects with (specifically, is perpendicular to) the rotation axis of the first gear 3A.

[0028] In this embodiment, the second gear 3B is a worm wheel (that is, a helical gear) that meshes with the first gear 3A. However, the second gear 3B is not limited to a worm wheel and may be, for example, a helical gear.

[0029] The driving force transmitted to the second gear 3B is transmitted via the output shaft 3C to displacement members such as cams and links of the movable mechanism (that is, the reclining device 15, the sliding device 16, the lifter device 17, and the tilt device 18).

[0030] <Rotary bearing> The rotary bearing 4 is an annular member that rotatably supports the shaft 2. The rotary bearing 4 is made of, for example, a sintered metal.

[0031] The rotary bearing 4 is disposed along the X-axis between the first gear 3A and the thrust bearing 7. Specifically, a portion of the shaft 2 that is closer to the tip of the shaft 2 (i.e., the end opposite the actuator 6) than the first gear 3A is inserted through the rotary bearing 4.

[0032] <Housing> The housing 5 shown in FIG. 2 accommodates at least the shaft 2, the first gear 3A, the rotary bearing 4, and the second gear 3B.

[0033] The housing 5 has a shaft accommodating portion 51, a holder 52 (see FIG. 3), a second gear accommodating portion 53, and an actuator connecting portion 54. The housing 5 is made of a material such as resin.

[0034] The shaft accommodating portion 51 is a cylindrical portion that accommodates the first gear 3A. The shaft accommodating portion 51 protrudes along the X-axis from the actuator connecting portion 54. As shown in FIG. 4 , the shaft accommodating portion 51 has a restricting portion 511, a holder receiving portion 512, and a cap receiving portion 513.

[0035] The restricting portion 511 restricts movement of the action portion 71 of the thrust bearing 7 of the holder 52 in the direction of transmission of the thrust load (i.e., the direction parallel to the X-axis and away from the shaft 2) by coming into contact with the end portion of the holder 52. The restricting portion 511 is configured as a portion of the shaft accommodating portion 51 where part of the inner circumferential surface protrudes radially inward (i.e., a portion with a reduced diameter).

[0036] Holder receiving portion 512 is a portion into which holder anti-rotation portion 523 of holder 52 is inserted. As shown in Fig. 5A, holder receiving portion 512 has an inner peripheral surface of a polygonal shape that is substantially the same shape as the outer peripheral surface of holder anti-rotation portion 523 when viewed in a direction parallel to the central axis.

[0037] The cap receiving portion 513 is a portion into which the retaining portion 82 of the cap 8 is inserted. As shown in Fig. 5B, when viewed in a direction parallel to the central axis, the cap receiving portion 513 is configured with a plurality of receiving grooves into which the serrations constituting the retaining portion 82 can be inserted.

[0038] 4, the holder 52 is a cylindrical member disposed inside the shaft accommodating portion 51. The holder 52 has a female thread portion 521, a bearing holding portion 522, and a holder rotation preventing portion 523.

[0039] The female thread portion 521 is threadedly engaged with the male thread portion 72 of the thrust bearing 7. The female thread portion 521 is a cylindrical body with a screw thread and a screw groove on its inner circumferential surface. The female thread portion 521 is provided outside the tip end of the shaft 2 in the axial direction of the shaft accommodating portion 51.

[0040] The bearing holder 522 holds the rotary bearing 4. The rotary bearing 4 is, for example, press-fitted into the bearing holder 522. As shown in Fig. 3, the bearing holder 522 has a plurality of slits 522A extending from the end of the holder 52 along the X-axis.

[0041] The holder anti-rotation portion 523 is a portion that restricts rotation of the female screw portion 521 and the bearing holding portion 522 about the central axis of the shaft 2 relative to the shaft accommodating portion 51. The holder anti-rotation portion 523 is configured by a cylindrical body that configures the female screw portion 521.

[0042] The holder anti-rotation portion 523 has a polygonal outer peripheral surface when viewed from the axial direction of the female screw portion 521. When the holder anti-rotation portion 523 is inserted into the holder receiving portion 512 of the shaft accommodating portion 51, rotation of the entire holder 52 is restricted.

[0043] 2 accommodates the second gear 3B. The internal space of the second gear accommodating portion 53 communicates with the internal space of the shaft accommodating portion 51. The actuator connecting portion 54 is a portion connected to the actuator 6. The shaft 2 is disposed across the interior of the actuator connecting portion 54 and the interior of the shaft accommodating portion 51.

[0044] <Actuator> The actuator 6 is a power source that drives the shaft 2. For example, a motor is used as the actuator 6. However, the actuator 6 may also rotate the shaft 2 by air pressure or hydraulic pressure.

[0045] <Thrust bearing> As shown in FIG. 4, the thrust bearing 7 has an acting portion 71, a male thread portion 72, and an engaged portion 73.

[0046] The action portion 71 is a portion that comes into contact with the tip end of the shaft 2. The action portion 71 is pressed in a direction parallel to the X-axis by the shaft 2. The action portion 71 constitutes the inner end portion of the thrust bearing 7.

[0047] The action portion 71 may be integrally molded with the male screw portion 72 using resin, or may be formed from, for example, metal as a member independent of the male screw portion 72. The shape of the action portion 71 is not particularly limited, and may be spherical.

[0048] The male screw portion 72 is screwed into the female screw portion 521 of the holder 52. The male screw portion 72 is a cylindrical or columnar body having a screw thread and a screw groove on its outer circumferential surface. The male screw portion 72 is disposed adjacent to the action portion 71.

[0049] The engaged portion 73 is disposed in a position sandwiching the male thread portion 72 together with the acting portion 71 in the axial direction of the shaft 2. The engaged portion 73 also includes the outer end portion of the thrust bearing 7 (i.e., the end portion opposite the acting portion 71). The engaged portion 73 is integrated with the male thread portion 72. The male thread portion 72 and the engaged portion 73 are made of a material such as resin.

[0050] The engaging portion 81 of the cap 8 engages with the engaged portion 73. The engaged portion 73 penetrates the cap 8 along the X axis. At least a portion of the engaged portion 73 protrudes from the shaft accommodating portion 51 of the housing 5.

[0051] 6A and 6B, the engaged portion 73 has an insertion portion 731, a plurality of recesses 732, and a plurality of slits 733. Note that in Figures 6A and 6B, the threads and grooves of the male screw portion 72 are not shown.

[0052] The insertion portion 731 is a portion that restricts rotation of the male thread portion 72 about the central axis of the shaft 2 relative to the cap 8. The insertion portion 731 is configured as a cylindrical body having a polygonal outer circumferential surface when viewed from the axial direction. By inserting the insertion portion 731 into the first base portion 811 of the cap 8, rotation of the entire thrust bearing 7 is restricted.

[0053] The recesses 732 are recessed portions of the outer circumferential surface of the insertion portion 731. The recesses 732 each extend in the radial direction of the insertion portion 731 and are separated from one another by slits 733. The slits 733 extend from the end of the insertion portion 731 along the X-axis.

[0054] <Cap> As shown in FIG. 4, the cap 8 is inserted into the end of the shaft accommodating portion 51 (that is, the opening).

[0055] The cap 8 is disposed on the outer side of the housing 5 relative to the holder 52. The cap 8 has an engagement portion 81, a retaining portion 82, and a cap rotation preventing portion 83. The material of the cap 8 is, for example, resin.

[0056] The engaging portion 81 engages with the engaged portion 73 of the thrust bearing 7. The engaging portion 81 restricts movement of the thrust bearing 7 along the X-axis relative to the cap 8. As shown in FIGS. 7A and 7B , the engaging portion 81 has a first base portion 811 and a plurality of first uneven portions 812.

[0057] The first base portion 811 is a cylindrical portion into which the insertion portion 731 of the thrust bearing 7 is inserted. The first base portion 811 has an inner peripheral surface that is polygonal and has substantially the same shape as the outer peripheral surface of the insertion portion 731 when viewed in a direction parallel to the central axis.

[0058] The first uneven portions 812 are provided on the inner circumferential surface of the first base portion 811, and protrude radially inward from the inner circumferential surface of the first base portion 811. Each of the multiple first uneven portions 812 engages with one of the multiple recesses 732 of the thrust bearing 7.

[0059] The retaining portion 82 is a portion attached to the shaft accommodating portion 51 so as to restrict the thrust bearing 7 from coming off from the shaft accommodating portion 51 of the housing 5. In this embodiment, the retaining portion 82 is formed by a cylindrical body that constitutes the first base portion 811.

[0060] The retaining portion 82 is inserted into the shaft accommodating portion 51 with enough strength to prevent it from coming off the shaft accommodating portion 51 due to the thrust load of the shaft 2. Specifically, the retaining portion 82 is fitted into the cap receiving portion 513 of the shaft accommodating portion 51 by, for example, press-fitting so as to generate axial sliding resistance (i.e., frictional resistance) with respect to the cap receiving portion 513. In other words, the retaining portion 82 is compressed by the cap receiving portion 513 so as to generate radial stress on the cap receiving portion 513.

[0061] The cap anti-rotation portion 83 is a portion that restricts rotation of the engagement portion 81 and the retaining portion 82 around the central axis of the shaft 2 relative to the housing 5. The cap anti-rotation portion 83 extends from the outer peripheral surface of the retaining portion 82 and is configured as a serration having a plurality of teeth that are juxtaposed along the circumferential direction of the retaining portion 82.

[0062] 5B, the teeth of the cap anti-rotation portion 83 are inserted into the receiving grooves of the cap receiving portion 513. This restricts the rotation of the entire cap 8 relative to the housing 5.

[0063] The thrust bearing 7 and the cap 8 may be connected by, for example, a flexible connecting band, which is integrally molded with the thrust bearing 7 and the cap 8 using, for example, resin.

[0064] <Gearbox manufacturing method> The following describes a manufacturing method (that is, an assembly method) for the gearbox 1. The manufacturing method of this embodiment includes a holder inserting step, a shaft inserting step, a thrust bearing screwing step, and a cap attaching step.

[0065] <Holder insertion process> In this step, the holder 52 holding the rotary bearing 4 is inserted into the shaft accommodating portion 51 of the housing 5 from the inside of the housing 5 toward the outside of the housing 5 (that is, the opening).

[0066] <Shaft insertion process> In this step, the actuator 6 to which the shaft 2 is connected is connected to the housing 5. As a result, the shaft 2 is inserted into the holder 52 and the rotary bearing 4 arranged in the shaft accommodating portion 51, and the shaft 2 is positioned relative to the housing 5.

[0067] <Thrust bearing screwing process> In this step, the thrust bearing 7 is inserted into the shaft accommodating portion 51 through the opening of the shaft accommodating portion 51 in which the shaft 2 is disposed.

[0068] Thereafter, the thrust bearing 7 is rotated about its axis to thread the male thread portion 72 into the female thread portion 521 of the holder 52, thereby connecting the thrust bearing 7 to the holder 52. In addition, the acting portion 71 of the thrust bearing 7 is adjusted to a position that suppresses rattle at the tip of the shaft 2 by adjusting the feed amount (i.e., the tightening amount) of the male thread portion 72.

[0069] <Cap attachment process> In this step, the cap 8 is attached to the thrust bearing 7 connected to the holder 52, and the cap 8 is fitted into the shaft accommodating portion 51.

[0070] Specifically, while the cap 8 is pressed into the cap receiving portion 513 of the shaft accommodating portion 51, the cap 8 is slid relative to the thrust bearing 7, thereby engaging the engaging portion 81 of the cap 8 with the engaged portion 73 of the thrust bearing 7. The cap 8 engages with the thrust bearing 7 while elastically deforming, and is press-fitted into the cap receiving portion 513.

[0071] [1-2.Effects] According to the embodiment described above in detail, the following effects can be obtained. (1a) The cap 8 restricts the movement of the thrust bearing 7 in the axial direction of the shaft 2. This minimizes the fastening torque between the male thread portion 72 of the thrust bearing 7 and the female thread portion 521 of the housing 5. This suppresses an increase in sliding resistance at the end of the shaft 2 and also suppresses rattle of the shaft 2.

[0072] (1b) The cap rotation preventing portion 83 of the cap 8 restricts the rotation of the thrust bearing 7 relative to the housing 5, thereby preventing loosening of the fastening between the male screw portion 72 and the female screw portion 521.

[0073] (1c) The anti-rotation portion 83 of the cap 8 is configured by serrations extending from the retaining portion 82, and therefore the anti-rotation effect of the cap 8 relative to the housing 5 can be improved with a relatively simple configuration.

[0074] (1d) Since the holder 52 has the female screw portion 521 and the bearing holding portion 522, the rotary bearing 4 and the female screw portion 521 can be disposed inside the housing 5 by inserting the holder 52 into the shaft accommodating portion 51.

[0075] (1e) The rotation and movement of the holder 52 are restricted by the holder anti-rotation portion 523 of the holder 52 and the restricting portion 511 of the shaft accommodating portion 51, thereby preventing loosening of the fastening between the male screw portion 72 and the female screw portion 521.

[0076] (1f) The engagement portion 81 of the cap 8 has the first uneven portion 812, which makes it possible to increase the engagement strength of the cap 8 with the thrust bearing 7 with a relatively simple configuration.

[0077] 2. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0078] (2a) In the gearbox for a vehicle seat according to the above embodiment, as shown in Fig. 8, the retaining portion 82 of the cap 8 may have a second base portion 821 and a second uneven portion 822. The second base portion 821 is a cylindrical portion inserted into the housing 5 and is part of the cylindrical body that constitutes the first base portion 811.

[0079] The second uneven portion 822 is a recess or a protrusion provided on the outer peripheral surface of the second base portion 821. The second uneven portion 822 engages with a protrusion or a recess provided on the inner peripheral surface of the cap receiving portion 513 of the housing 5. This can improve the effect of preventing the cap 8 from coming off the housing 5 with a relatively simple configuration.

[0080] (2b) In the gearbox for a vehicle seat according to the above embodiment, the first uneven portion in the engaging portion of the cap may be a recess that engages with a protrusion provided in the engaged portion of the thrust bearing.

[0081] (2c) In the gearbox for a vehicle seat according to the above embodiment, the retaining portion of the cap may have a structure (for example, a snap-fit ​​structure) that engages with the end of the shaft accommodating portion from the outside of the housing.

[0082] (2d) In the gearbox for a vehicle seat of the above embodiment, the anti-rotation portion of the cap may be configured with a polygonal outer peripheral surface when viewed from the axial direction instead of serrations. The anti-rotation portion of the holder may also be configured with serrations. Furthermore, the insertion portion of the thrust bearing may have serrations.

[0083] (2e) In the gearbox for a vehicle seat of the above embodiment, the cap does not necessarily have to be attached to the housing. As shown in Fig. 9A, the gearbox for a vehicle seat may include a cap 8A that is not directly attached to the housing 5, and a thrust bearing 7A with the cap 8A inserted therein.

[0084] The thrust bearing 7A has an engaged portion 73 provided outside the housing 5 relative to the male thread portion 72. The engaged portion 73 is formed of a claw that protrudes radially inward of the thrust bearing 7A.

[0085] The cap 8A has an engaging portion 81 that engages with the engaged portion 73 from inside the thrust bearing 7A, and a retaining portion 82 that is inserted into the thrust bearing 7A so as to press the thrust bearing 7A against the housing 5. The engaging portion 81 is fitted into the engaged portion 73 of the thrust bearing 7A by snap fitting. In addition, the pressing force of the retaining portion 82 generates sliding resistance between the outer peripheral surface of the thrust bearing 7A and the inner peripheral surface of the shaft accommodating portion 51 of the housing 5.

[0086] 9B, cap 8A has a groove 84 that is hooked onto engaged portion 73 of thrust bearing 7A before it is screwed into housing 5. The thrust bearing 7A can be screwed into the cap 8A while it is held by the thrust bearing 7A by this groove 84. After screwing, cap 8A is press-fitted into the thrust bearing 7A, which simplifies the process of attaching the thrust bearing 7A and cap 8A to the housing 5.

[0087] (2f) In the gearbox for a vehicle seat of the above embodiment, the housing does not necessarily have to have a holder. For example, a female screw portion may be provided in the shaft accommodating portion of the housing.

[0088] (2g) The function of one component in the above embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. All aspects included in the technical idea identified by the wording of the claims are embodiments of the present disclosure. [Explanation of symbols]

[0089] 1... gearbox, 2... shaft, 3A... first gear, 3B... second gear, 4... rotary bearing, 5...housing, 6...actuator, 7, 7A...thrust bearing, 8, 8A...cap, 10...vehicle seat, 15...recliner device, 16...slide device, 17...lifter device, 18...tilt device, 51...shaft accommodating portion, 52...holder, 53...second gear accommodating portion, 54...actuator connecting portion, 71...action portion, 72...male thread portion, 73...engaged portion, 81...engaging portion, 82...retaining portion, 83...cap rotation prevention portion, 84...groove, 511...regulating portion, 512...holder receiving portion, 513...cap receiving portion, 521...female thread portion, 522...bearing holding portion, 523...holder rotation prevention portion, 731...insertion portion, 732...recessed portion, 811...first base portion, 812...first uneven part, 821...second base, 822...second uneven part.

Claims

1. A gear box for a vehicle seat used in a movable mechanism configured to displace a portion of a vehicle seat, comprising: A shaft, a gear fixed to the shaft; a rotary bearing that rotatably supports the shaft; a housing that accommodates the shaft, the gear, and the rotary bearing and has a female thread portion; a thrust bearing having an action portion that contacts an end of the shaft, a male thread portion that is screwed into the female thread portion, and an engaged portion that is arranged in a position that sandwiches the male thread portion together with the action portion in the axial direction of the shaft; a cap having an engaging portion that engages with the engaged portion of the thrust bearing and a retaining portion that prevents the thrust bearing from coming off the housing; Equipped with The retaining portion is press-fitted between the housing and the thrust bearing; The housing has a protrusion or a recess, and the retaining portion has a recess that engages with the protrusion of the housing, or a protrusion that engages with the recess of the housing, or A gearbox for a vehicle seat, the gearbox being inserted into the thrust bearing so as to press the thrust bearing against the housing.

2. 2. A gear box for a vehicle seat according to claim 1, The retaining portion is attached to the housing, The cap has a cap rotation preventing portion that prevents the engaging portion and the retaining portion from rotating about the central axis of the shaft relative to the housing.

3. 3. A gear box for a vehicle seat according to claim 2, the retaining portion is a cylindrical body inserted into the housing, The cap anti-rotation portion is a serration extending from an outer peripheral surface of the retaining portion and having a plurality of teeth arranged in parallel along the circumferential direction of the retaining portion.

4. A gear box for a vehicle seat according to any one of claims 1 to 3, The housing includes: a cylindrical shaft accommodating portion; a cylindrical holder disposed inside the shaft accommodating portion; and The holder is The female screw portion; a bearing holder that holds the rotary bearing; A gearbox for a vehicle seat, comprising:

5. 5. A gear box for a vehicle seat according to claim 4, the holder has a holder anti-rotation portion that restricts rotation of the female thread portion and the bearing holding portion relative to the shaft accommodating portion about a central axis of the shaft, The shaft accommodating portion has a restricting portion that restricts movement of the action portion of the holder in a direction in which a thrust load is transmitted.

6. A gear box for a vehicle seat according to any one of claims 1 to 3, The engagement portion is a cylindrical first base portion into which the engaged portion of the thrust bearing is inserted; a first uneven portion provided on an inner circumferential surface of the first base portion; A gearbox for a vehicle seat, comprising:

7. 4. A gear box for a vehicle seat according to claim 2 or 3, a recess that engages with the protrusion of the housing, or a protrusion that engages with the recess of the housing as a second concave-convex portion, The retaining portion is a cylindrical second base portion inserted into the housing; the second uneven portion provided on the outer peripheral surface of the second base portion; A gearbox for a vehicle seat, comprising:

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