Electric seat slide device

Abstract

To provide an electric seat slide device that enhances the supporting force of a protective cover against a motor housing or gearbox and has the high versatility of the protective cover.SOLUTION: A protective cover 50 which is arranged so as to extend between a first cylindrical part 18 and a second cylindrical part 9, includes: at one end, a cylindrical motor-side holding portion 52 that is fitted onto the outer peripheral surface of a motor housing 6a so as to be movable in the axial direction of output shafts 6b, 6c of an electric motor 6 and has an opening gap S whose lower part is open; and at the other end being a first gearbox 4 side, a gearbox-side holding portion 53 that has fitting recesses 57, 57 that are slidably fitted in the axial direction of the output shaft to fitting projections 29, 29 provided on both side walls of the first gearbox, and has a locking claw 58 that is engaged with a locking surface 4d on an outer surface 4c of the first gearbox to restrict movement in the direction of the output shaft in a state where the fitting recesses are engaged with the fitting projections.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an electric seat slide device for a vehicle seat, for example.

Background Art

[0002] As conventional electric seat slide devices for vehicles, those described in Patent Documents 1 and 2 below are known.

[0003] The electric seat slide device described in Patent Document 1 includes a pair of lower rails arranged and fixed along the longitudinal direction of the vehicle floor, a pair of upper rails slidably fitted along the longitudinal direction to each of the lower rails and coupled to the vehicle seat, a pair of screw shafts arranged along the internal longitudinal direction of each of the upper rails and having male threads formed on the outer periphery, a pair of nut members fixed at predetermined positions inside each of the lower rails and having female screw holes into which the respective screw shafts are screwed, a gear box provided on each of the left and right upper rails and housing a gear mechanism for driving the nut members, an electric motor provided between the left and right upper rails and transmitting a driving force to each of the gear mechanisms, and a transmission member transmitting the output shaft of the electric motor and the input shaft of each of the gear mechanisms.

[0004] A pair of openings for assembling a pair of gear boxes are respectively formed in the left and right upper rails, and one of the openings is closed by a motor fixing bracket for assembling the motor. A bridging bracket for bridging the two brackets is provided between a reinforcing bracket provided on the other upper rail and the motor fixing bracket.

[0005] However, the bridging brackets described in Patent Document 1 are all assembled to the long brackets and the upper rails by a fitting method using their own flexural deformation. Since these assembling operations are performed from above and below using flexural deformation, the assembling workability is poor, leading to a decrease in the mounting work efficiency.

[0006] The electric seat slide device described in Patent Document 2 was previously filed by the applicant of the present application. It is arranged to extend between the first cylindrical portion on the electric motor side and the second cylindrical portion on the second gearbox side, and has a protective cover that covers the second gearbox, the first and second cylindrical portions, and the transmission member from above. This protective cover has an insertion hole into which the first cylindrical portion can be inserted from the axial direction, and a rotation restricting groove provided on the inner peripheral surface of the insertion hole, into which the rotation restricting portion can be engaged from the axial direction.

[0007] When assembling the protective cover, it is arranged to cover the entire transmission member, and after one end portion is obliquely fitted axially from the first cylindrical portion side, when the other end portion is pressed downward in this state, a pair of locking claws provided on the left and right of the other end portion are locked and fitted and held in a pair of locking recesses provided in the second gearbox from above. As a result, the protective cover covers the transmission member while both end portions are fitted and fixed to the first cylindrical portion and the second gearbox, improving the assembly workability.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, although the assembly workability of the protective cover of the electric seat slide device described in Patent Document 2 can be improved, as described above, since a pair of locking claws provided on the left and right of the other end portion of the protective cover are locked and fitted and held in a pair of locking recesses provided in the first gearbox from above, the supporting force in the vertical direction becomes insufficient. As a result, when an upward force is applied to the other end portion, the protective cover is likely to be detached from the first gearbox.

[0010] In addition, since one end of the protective cover is fitted and supported with respect to the first cylindrical portion that engages the transmission member with the output shaft of the electric motor, it cannot be adopted unless the first cylindrical portion has sufficient strength. In other words, since the first cylindrical portion may have a structure in which sufficient strength against the protective cover cannot be obtained structurally, it causes a technical problem such as poor versatility of the protective cover.

[0011] The present invention has been devised in view of the technical problems of the prior art, and aims to improve the assembly work efficiency of the protective cover, improve the supporting force of the protective cover against the motor housing and the gearbox, and provide an electric seat slide device with high versatility of the protective cover.

Means for Solving the Problems

[0012] As one aspect of the present invention, a pair of left and right rail assemblies disposed along the longitudinal direction of the vehicle body on both left and right sides of a vehicle seat includes a pair of lower rails fixed to the vehicle floor, a pair of upper rails slidably attached to the pair of lower rails and to which the vehicle seat is attached, a pair of screw shafts rotatably disposed inside between each upper rail and each lower rail and having male threads formed on their respective outer circumferences, a pair of nut members fixed to each lower rail and having female screw holes into which the male threads of each screw shaft are screwed, a pair of gear boxes fixed to each upper rail and each having a gear mechanism for rotationally driving either one of each screw shaft and each nut member, an electric motor fixed to one of the gear boxes disposed between the pair of upper rails and fixed to one of the upper rails, a transmission member connecting the output shaft of the electric motor and the input shaft of the gear mechanism in the other gear box fixed to the other upper rail, a cylindrical motor housing extending along the axial direction of the output shaft of the electric motor, a motor-side cylindrical portion provided at one end of the motor housing on the other gear box side and into which one end portion of the transmission member can be inserted, a gear-box-side cylindrical portion provided in the other gear box, facing the motor-side cylindrical portion in the axial direction and into which the other end portion of the transmission member can be inserted, and a protective cover extending between the motor housing and the other gear box and covering the transmission member, the motor-side cylindrical portion, and the gear-box-side cylindrical portion from above and having an open bottom surface. The protective cover has, at one end on the electric motor side, a cylindrical motor-side holding portion that is movably fitted in the axial direction of the output shaft to the outer circumferential surface of the motor housing and has an opening gap with an open lower portion. At the other end on the other gear box side, it has a fitting recess that is slidably fitted in the axial direction of the output shaft to a fitting projection provided at the upper end of the other gear box, and a gear-box-side holding portion having a regulating claw that regulates movement in the axial direction of the output shaft in a state where the fitting recess is fitted to the fitting projection.

Advantages of the Invention

[0013] According to the present invention, it is possible to improve the assembly work efficiency for the motor housing, transmission members, etc. of the protective cover.

[0014] In addition, the vertical coupling force of the protective cover to the motor housing and the gear box is increased, accidental detachment upward is suppressed, and the versatility of the protective cover with respect to the electric motor is enhanced.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment in which the electric seat slide device according to the present invention is used in a vehicle will be described in detail with reference to the drawings.

[0017] FIG. 1 is a perspective view showing a rail assembly provided in an embodiment of the electric seat slide device according to the present invention, FIG. 2 is an exploded perspective view showing the other side of the rail assembly provided in the embodiment of the present invention where the electric motor is not fixed, FIG. 3 is a longitudinal sectional view of the basic components of the rail assembly provided in this embodiment, and FIG. 4 is a plan view showing the first gearbox provided in this embodiment.

[0018] In addition, the "front-rear direction" in this specification is the front-rear direction in a state where the electric seat slide device is fixed to the floor surface of the vehicle body, that is, the front-rear direction of the vehicle body. Further, the "up-down direction" in this specification is a direction orthogonal to the up-down direction of the rail assembly arranged in the front-rear direction of FIG. 1. When the rail assembly is fixed to the floor surface of the vehicle body with an inclination in the up-down direction, the "up-down direction" may not coincide with the direction orthogonal to the floor surface of the vehicle body.

[0019] As shown in FIGS. 1 to 3, the electric seat slide device includes a pair of left and right rail assemblies disposed along the longitudinal direction of the vehicle body on both the left and right sides of the vehicle seat.

[0020] This rail assembly includes a pair of lower rails 1 made of metal disposed along the longitudinal direction of the vehicle body floor (not shown), a pair of upper rails 2 made of metal slidably attached to each lower rail 1 along the longitudinal direction of the lower rail, a pair of screw shafts 3 made of metal rotatably supported inside each upper rail 2, and a serration portion 32 (described later) provided at the front end of each screw shaft 3. A pair of first and second gear boxes 4 and 5 each having a gear mechanism for rotationally driving each screw shaft 3 engaged therewith, an electric motor 6 disposed between both upper rails 2 for rotationally driving each gear mechanism inside the first and second gear boxes 4 and 5 via transmission members 8 and 16, a nut member 7 (see FIG. 2) fixed to each lower rail 1 and having a female screw hole 40 into which each screw shaft 3 is screwed (meshed), and a plurality of slide guide members (not shown) for reducing the frictional resistance when each upper rail 2 slides inside each lower rail 1 when a load in the longitudinal direction acts on each upper rail 2.

[0021] The assembly in which each lower rail 1 incorporates each upper rail 2 and each gear box 4 and 5 is arranged in a pair of left and right as a set between the vehicle seat (not shown) and the floor, and is arranged parallel to each other along the longitudinal direction of the vehicle.

[0022] As shown in FIGS. 1 and 2, each lower rail 1 includes a lower rail bottom wall 11 fixed to the floor surface of the vehicle body, a pair of lower rail outer walls 12 on both sides of the lower rail bottom wall 11, a pair of lower rail upper walls 14 extending inward from the tips of each lower rail outer wall 12, and a pair of lower rail inner walls 15 extending from the tips of each lower rail upper wall 14 toward the lower rail bottom wall 11.

[0023] The distance between the opposing pair of inner walls 15 of the lower rails is set so that the upper rail 2 accommodated in the lower rail 1 can slide.

[0024] Each lower rail 1 is fixed to the floor of the vehicle body through leg brackets (not shown) at two locations in the longitudinal front and rear. The leg brackets are fixed to the bottom wall 11 of the lower rail by rivets.

[0025] As shown in FIGS. 1 and 2, the upper rail 2 has an upper rail top wall 21 fixed to the back side of the seat, a pair of upper rail side walls 22 on both sides of the upper rail top wall 21, and an upper rail bent wall 24 that extends while being folded back upward and outward from the tip of each upper rail side wall 22. A vehicle seat is attached via a side bracket (not shown) fixed to the upper surface of the upper rail 2 by laser welding.

[0026] When the upper rail 2 is attached to the lower rail 1, the tip of each upper rail bent wall 24 enters between the outer wall 12 and the inner wall 15 of the lower rail. That is, the tip of each upper rail bent wall 24 overlaps with the inner wall 15 of the lower rail.

[0027] Also, as shown in FIG. 2, the upper rail 2 has three slits 25 with a predetermined width for arranging and fixing two front and rear reinforcing plates 27 on the upper rail top wall 21 and the upper rail side walls 22 at the front end 2a and the rear end 2b. By deforming the tongue piece 25a formed on the side wall 22 so as to be pushed into each recess 27b provided on both side surfaces of the reinforcing plate 27, each reinforcing plate 27 is fixed to the upper rail 2. Each of these reinforcing plates 27 has a through hole 27a formed at the center through which a screw shaft 3 is rotatably inserted.

[0028] Each screw shaft 3 is disposed between a pair of upper rail side walls 22 of the upper rail body 23. The screw shaft 3 includes a screw shaft main body 31 that penetrates through a nut member 7, a serration portion 32 provided at the front end and attached to the first and second gear boxes 4 and 5, and a small-diameter shaft portion 33 provided at the rear end and rotatably supported by an end cap 34 attached to the rear end surface of the upper rail 2.

[0029] The screw shaft main body 31 is formed with a male thread 31a that is screwed into and meshes with a female thread hole 40 of the nut member 7 described later on the outer peripheral surface.

[0030] The serration portion 32 is provided at the front end of the screw shaft 3 on the vehicle front side, and is formed with a smaller diameter than the screw shaft main body 31 so as not to interfere with the female thread hole 40 of the nut member 7 during assembly. The serration portion 32 is formed with male serration teeth that fit with a worm wheel 43 described later that constitutes a gear mechanism disposed in each of the gear boxes 4 and 5.

[0031] The small-diameter shaft portion 33 is provided at the rear end of the screw shaft 3 on the vehicle body rear side, and is rotatably supported within a cylindrical portion 34a of the end cap 34. Also, the small-diameter shaft portion 33 is formed in a cylindrical shape with a smaller diameter than the screw shaft main body 31 so as not to interfere with the female thread hole 40 of the nut member 7.

[0032] The screw shaft 3 is fixed integrally with the worm wheel 43 by a nut 35 screwed onto a screw portion 32a provided at the tip of the serration portion 32, and is prevented from coming out rearward. This nut 35 sandwiches the worm wheel 43 described later of the gear box 4 in the screw shaft axial direction via washers 36 that face each other with the gear box 4 therebetween.

[0033] Each screw shaft 3 and each nut member 7 constitute a screw mechanism that axially moves each upper rail 2 with respect to each lower rail 1.

[0034] As shown in FIGS. 1 to 4, the first and second gear boxes 4 and 5 are formed in a box shape that can be divided in the left-right direction by, for example, a zinc alloy material. A pair of pins 26, 26 provided on one divided body side with their respective dividing surfaces aligned penetrate holes provided on the other divided body side, and are joined by caulking the tips of the protruding pair of pins 26, 26.

[0035] The first and second gear boxes 4 and 5 are arranged between the upper rail side walls 22 of each upper rail 2, and are respectively joined to each upper rail 2 by caulking a pair of pins 46, 46 that penetrate in the left-right direction.

[0036] In FIG. 1, the left first gear box 4, as also shown in FIG. 4, has a box body 4a and a second cylinder part 9 which is a gear box side cylinder part integrally provided on the inner surface 4b on the side of the electric motor 6 of the box body 4a. The box body 4a has an outer surface 4c at a position opposite to the inner surface 4b, and as shown in FIGS. 1, 2, and 4, at the upper parts of both side portions, fitting recesses 57, 57 provided in the gear box side holding part 53 of a protection cover 50 to be described later are slidably fitted in the axial direction of the output shafts 6b, 6c of the electric motor 6. A pair of fitting protrusions 29, 29 are provided. Each of these fitting protrusions 29, 29 protrudes in the left-right horizontal direction and is formed in a substantially horizontal V-shaped cross section. The box body 4a has a locking surface 4d provided at the upper part of the outer surface 4c, where an elastically deformable regulating claw 58 provided at the center in the width direction of the gear box side holding part 53 of the protection cover 50 to be described later slides from the axial direction and is elastically locked from above.

[0037] As shown in FIGS. 2 and 3, the second cylinder part 9 is formed in an elongated cylindrical shape and is integrally provided with the box body 4a. An insertion hole 9a into which one end 8c of a flexible shaft 8a of a transmission member 8 to be described later is inserted is formed to penetrate in the internal axial direction. Further, the second cylinder part 9 has a large-diameter hole 9b formed with a predetermined length, into which one end of an outer tube 8b of the transmission member 8 to be described later is inserted and held, on the inner peripheral surface on the side of one axial end opening of the insertion hole 9a.

[0038] In FIG. 1, as shown in FIGS. 1 and 3, on the inner surface of the right second gear box 5 on the side of the electric motor 6 of the box body 5a, a third cylindrical portion 10 is provided so as to project in the direction of the electric motor 6. The third cylindrical portion 10 is formed in a substantially triangular box shape in plan view, is provided integrally with the box body 5a of the second gear box 5, and has an insertion hole 10a through which a second transmission member 16 is inserted in the internal axial direction. Further, the third cylindrical portion 10 is integrally provided with a large-diameter cylindrical holding portion 10b at the tip on the side of the electric motor 6. This holding portion 10b is axially superposed on a mounting portion 6d (to be described later) of the motor housing 6a of the electric motor 6, and is fixed to the mounting portion 6d by two bolts 17 passing through through holes provided in the holding portion 10b. The second transmission member 16 is a flexible shaft formed in a single bar shaft shape. One axial end portion 16a is inserted into a deformed hole provided in the input shaft 42a of the worm 42 constituting the gear mechanism and is integrally rotatably connected, and the other axial end portion 16b is axially connected to one output shaft 6c of the electric motor 6.

[0039] As described above, the first and second gear boxes 4 and 5 each incorporate a gear mechanism, and are caulked and fixed to the front end portions 2a of both side walls 22 of the upper rail 2 by the pin members 46 shown in FIG. 2.

[0040] As shown in FIG. 3, each gear mechanism has a worm gear including a resin worm 42 and a resin worm wheel 43 meshing therewith.

[0041] Each worm 42 is rotationally driven in the forward or reverse direction by the electric motor 6 via the first and second transmission members 8 and 16. When each worm 42 is rotationally driven in the forward or reverse direction, each worm wheel 43 meshing therewith rotates.

[0042] The worm wheel 43 is provided with a female serration portion 44 that fits into the male serration of the serration portion 32 of the screw shaft 3 on the inner peripheral surface of the central hole.

[0043] Therefore, each screw shaft 3 rotates while being supported by the upper rail 2 as each worm wheel 43 rotates with the rotation of each worm 42. Since the upper rail 2 is screwed to the nut member 7 to which each screw shaft 3 is fixed to the lower rail 1, when the worm wheel 43 rotates, the upper rail 2 slides in the forward or backward direction with respect to the lower rail 1.

[0044] The electric motor 6 has a general structure. As shown in FIG. 3, it includes a motor housing 6a made of a metal material that houses electrical components such as a stator and a rotor (not shown) inside, a pair of output shafts 6b, 6c made of a metal material that extend from the center of the rotor housed in the motor housing 6a in the left - right axial direction, and a mounting portion 6d made of a resin material that is provided on one end side of the motor housing 6a, has a screw hole for fixing the electric motor 6 to the holding portion 10d, and integrally has a socket for supplying power to the electric motor 6.

[0045] On the other end side of the motor housing 6a, as shown in FIGS. 1 and 3, a first cylindrical portion 18, which is a motor - side cylindrical portion formed in a cylindrical shape extending in the axial direction of the electric motor 6 and protruding toward the first gear box 4, is attached. The first cylindrical portion 18 is inserted into the axially protruding portion of the motor housing 6a with a fitting portion 18b fitting into a resin material, and is locked by elastic claws at the edge portion of the central hole. Also, an insertion hole 18a is formed through which the other end 8d of the flexible shaft 8a of the first transmission member 8 and the other end of the outer tube 8b are inserted in the inner axial direction.

[0046] The electric motor 6 can adjust the position of the vehicle seat fixed to each upper rail 2 along the longitudinal direction of the lower rail (vehicle front - rear direction) with respect to each lower rail 1 through each screw shaft 3 by rotating the gear mechanisms (worm 42, worm wheel 43) of the first and second gear boxes 4, 5.

[0047] As shown in FIGS. 1 and 3, the first transmission member 8 has a flexible shaft 8a and an outer tube 8b covering the outer peripheral surface of the flexible shaft 8a.

[0048] The flexible shaft 8a is formed to be bendable and deformable, and one end portion 8c protruding from the outer tube 8b is inserted (connected) into a hole portion of an input shaft 42a of a worm 42 in the first gear box 4 from inside the second cylindrical portion 9. The other end portion 8d protruding from the outer tube 8b is inserted (connected) into a hole portion of the other output shaft 6b of the electric motor 6 from inside the first cylindrical portion 18. The hole portions of the input shaft 42a of the worm 42 in the first gear box 4 and the hole portion of one output shaft 6b of the electric motor 6 are each formed to have a non-circular cross-sectional shape (substantially square shape). On the other hand, as shown in FIG. 3, one end portion 8c and the other end portion 8d of the flexible shaft 8a are formed to have a non-circular cross-sectional shape (substantially square shape) in accordance with the cross-sectional shape of each hole portion, and after being engaged with the two hole portions while matching the shapes, free relative rotation with each hole portion is restricted. Thereby, the rotational force of the electric motor 6 is efficiently transmitted to one screw shaft 31 via the flexible shaft 8a and via the gear mechanism (worm 42, worm wheel 43) of the first gear box 4.

[0049] The outer tube 8b is formed of a flexible synthetic resin material, and as described above, one end portion is inserted and fixed into the large-diameter hole 9b of the second cylindrical portion 9, and the other end portion is inserted and fixed into the first insertion hole 18a of the first cylindrical portion 18.

[0050] As shown in FIG. 2, the nut member 7 has a bracket 7a and a nut component 7b held together with an elastic member 7c inside the bracket 7a.

[0051] The bracket 7a is bent into an ohm shape and is positioned and fixed on the upper surface of the lower rail bottom wall 11 of the lower rail 1 by a pair of rivets 45 inserted into insertion holes respectively formed in a pair of bracket pieces 38 having a vehicle body front-rear direction. The bracket 7a has a shaft insertion hole 39a through which a screw shaft 3 is rotatably inserted formed in a pair of rising pieces 39 rising from the opposing edges of both bracket pieces 38.

[0052] The nut component 7b is formed in a block shape from a metal material and has a female screw hole 40 through which a male screw 31a of the screw shaft 3 is screwed (meshed) in the internal axial direction (vehicle body front-rear direction).

[0053] The elastic member 7c is formed by bending, for example, a rubber material into a U shape, is held inside the bracket 7a while being fitted to the nut component 7b, and has a pair of insertion holes 41 through which the screw shaft 3 is inserted formed in a pair of rising pieces.

[0054] A slide guide member (not shown) is disposed between the lower rail outer wall 12 and the upper rail bent wall 24. The slide guide member has a known structure in which a plurality of steel balls are held above and below a retainer, and is provided at two locations in the front and rear in the overlapping range of the longitudinal directions of the lower rail 1 and the upper rail 2.

[0055] Each upper rail 2 is configured such that a stopper portion (not shown) provided on each upper rail 2 abuts against a pair of front and rear stopper pieces 11a, 11b formed by cutting and raising the front and rear positions of the lower rail bottom wall 11 of the lower rail 1, thereby restricting the maximum front-rear movement position.

[0056] FIG. 5 is a perspective view showing a state in which a protective cover is assembled to the rail assembly provided in this embodiment, FIG. 6 is a longitudinal sectional view showing a state in which a protective cover is assembled to the rail assembly provided in this embodiment, FIG. 7 is a perspective view of the protective cover provided in this embodiment, FIG. 8 is a sectional view taken along line A-A of FIG. 7, FIG. 9 is a bottom view of the protective cover provided in this embodiment, FIG. 10 is a side view of the protective cover, FIG. 11 shows the motor-side holding portion of the protective cover, (a) is a left-side perspective view, and (b) is a right-side perspective view. FIG. 12 is a front view of the protective cover viewed from the motor-side holding portion side, FIG. 13 is a sectional view taken along line B-B of FIG. 6 showing a state in which the protective cover supports the motor housing in a holding state, FIG. 14 is a perspective view of the gearbox-side holding portion of the protective cover viewed from the bottom side, and FIG. 15 is a perspective view viewed from the plane side showing a state in which the gearbox-side holding portion of the protective cover is fitted and fixed to the first gearbox.

[0057] As shown in FIG. 5, between the first gearbox 4 and the motor housing 6a of the electric motor 6, a protective cover 50 is disposed that covers the first gearbox 4, the second cylindrical portion 9, the first cylindrical portion 18, and the entire transmission member 8 from above in the vertical direction.

[0058] As shown in FIGS. 5 and 6, this protective cover 50 is formed of a synthetic resin material into a cross-sectional shape with an open lower side and extends from the first gearbox 4 to the motor housing 6a. That is, as shown in FIGS. 5 to 10, the protective cover 50 has a long central portion 51 in the longitudinal direction, and one end portion that extends from the edge of the central portion 51 on the side of the electric motor 6 and covers a part of the first cylindrical portion 18 and the motor housing 6a, which is the motor-side holding portion 52, and the other end portion that extends from the edge of the central portion 51 on the side of the first gearbox 4 and has a substantially stepped plate-shaped cross-sectional shape, which is the gearbox-side holding portion 53.

[0059] The central portion 51 has a flat upper wall portion 51a, both side wall portions 51b, 51b extending downward from both end edges in the vehicle body front-rear direction of the upper wall portion 51a, and reinforcing horizontal portions 51h, 51h formed horizontally outward from the lower ends of the both side wall portions. As shown in FIG. 9, a plurality of central ribs 51c for reinforcement are provided at predetermined positions in the longitudinal direction on the lower surface of the upper wall portion 51a. Each of these central ribs 51c connects the upper wall portion 51a and the both side wall portions 51b, 51b, and an arcuate groove 51d having a concave shape is formed at the center of the lower surface so as not to interfere with the outer tube 8b. Further, flange portions 51k, 51k for reinforcement are formed along the edges on the lower surfaces of the both horizontal portions 51h, 51h, and a plurality of side ribs 51e for reinforcement are provided at predetermined positions in the longitudinal direction so as to be orthogonal to the flange portions 51k.

[0060] As also shown in FIGS. 6 to 9, the motor side holding portion 52 has a substantially C-shaped cross-sectional shape with the lower side open, and has a cylindrical holding portion main body 52a fitted into the motor housing 6a from the axial direction, and a conical portion 52b integrally provided for connecting the holding portion main body 52a and the central portion 51.

[0061] The holding part main body 52a is formed in a horizontally cylindrical shape with a C-shaped cross-section, and the lower side is cut parallel to the longitudinal direction (floor surface) of the motor housing 6a. An insertion hole H for fitting into the motor housing 6a is formed inside, and an opening gap S is formed along the longitudinal direction between the opposite both end portions 52f, 52f at the lower part. Further, the axial length L of the holding part main body 52a is set to a length that covers approximately half of the axial direction of the first cylindrical part 18 and the motor housing 6a. As shown in FIGS. 11(a), (b) and FIG. 12, the inner peripheral surface 52c of the holding part main body 52a is formed in a tapered shape that gradually increases in diameter from the inner edge on the conical part 52b side toward the front edge 52d on the motor housing 6a side. Note that the outer peripheral surface of the holding part main body 52a is formed with a uniform outer diameter along the axial direction. Further, on the inner peripheral surface 52c of the holding part main body 52a, a pair of protrusions 54, 54 are provided along the axial direction at two positions separated by a predetermined angle on the left and right with the upper end portion 52e as the center. Each of these protrusions 54, 54 is formed in a substantially V-shaped cross-section and protrudes toward the inner center of the holding part main body 52a, and the height h from the inner peripheral surface 52c to each tip portion 54a, 54a is formed to gradually decrease in the internal axial direction from the front edge 52d. This is because the inner peripheral surface 52c of the holding part main body 52a is formed in a tapered shape that gradually increases in diameter from the inside in the axial direction to the front edge 52d. When it is fitted onto the outer peripheral surface of the motor housing 6a, the tip portions 54a, 54a of the protrusions 54, 54 can be in line contact with the outer peripheral surface of the motor housing 6a. Therefore, even if the protective cover 50 is moved in the axial direction with respect to the motor housing 6a, it can be supported at the same height position in the vertical direction.

[0062] As shown in FIGS. 11 and 12, the holding part main body 52a is formed such that the radial wall thickness T gradually increases in the circumferential direction from both opposite end portions 52f, 52f on the opening gap S side to the upper end portion 52e in the radial direction, and this upper end portion 52e is formed with the maximum wall thickness. The holding part main body 52a is formed such that the reference radius R1 of the inner peripheral surface 52c passing through the tips 54a, 54a of the respective protruding parts 54, 54 is slightly smaller than the outer diameter of the outer peripheral surface of the motor housing 6a, and the radii R2, R2 of the inner peripheral surfaces of both end portions 52f, 52f, particularly the inner peripheral surfaces on the conical part 52b side in the longitudinal direction, are formed smaller than the reference radius R1. When assembled to the motor housing 6a, the opposite end portions 52f, 52f are in contact with the lower part of the outer peripheral surface of the end portion on the first cylindrical part 18 side in the longitudinal direction of the motor housing 6a so as to push it upward, and together with the two protruding parts 54, 54, they elastically hold and support it at four points in the circumferential direction.

[0063] The lower surface of the holding part main body 52a (the lower surfaces 52h, 52h of both end portions 52f, 52f) is horizontally cut along a horizontal plane parallel to the axial direction of the motor housing 6a, and as shown in FIG. 6, it is located above the lower end position of the motor housing 6a in the vertical direction, securing a space below the motor housing 6a.

[0064] Also, the holding part main body 52a is provided with a pair of protruding parts 55, 55 protruding forward at the lower parts on both opposite end portions 52f, 52f sides of the front edge 52d. These two protruding parts 55, 55 improve the insertability when fitting the holding part main body 52a to the outer peripheral surface of the motor housing 6a, and by supporting the relatively thin-walled both end portions 52f, 52f on the lower side, particularly the upper side of the holding part main body 52a, in a holding state over a wide area of the lower part of the motor housing 6a, it becomes stronger against the load acting to remove the holding part main body 52a upward. Note that since the inner peripheral surfaces 52c of both end portions 52f, 52f of the holding part main body 52a are horizontally cut parallel to the axial direction, the opening gap S is formed such that the gap on the conical part 52b side is narrow and the gap on the front edge 52d side is wide, achieving both improved insertability and holding strength of the motor housing 6a.

[0065] The conical portion 52b is formed such that its outer diameter gradually decreases along the direction from the rear edge of the holding portion main body 52a toward the central portion 51. When the holding portion main body 52a is fitted onto the outer peripheral surface of the motor housing 6a, it is arranged at a position that cooperates with the holding portion main body 52a to cover the outer peripheral surface of the first cylindrical portion 18.

[0066] As shown in FIGS. 7 to 9, FIGS. 14, and FIGS. 15, the gearbox side holding portion 53 has a box main body 53a having a substantially rectangular shape in plan view, and a rectangular connecting portion 53b integrally provided at the edge of the box main body 53a on the central portion 51 side. The box main body 53a and the connecting portion 53b are notched in a stepped shape such that the lower part becomes lower as it goes from the rear end wall 53c toward the central portion 51, and a stepped portion 53f is provided at the lower part between the box main body 53a and the connecting portion 53b. The connecting portion 53b is provided with an arch-shaped fitting groove 53e into which the second cylindrical portion 9 can be fitted from above by a plurality of rib-shaped wall pieces 53d at the lower part, similar to the central rib 51c of the central portion 51. The stepped portion 53f is configured to abut against the inner surface 4b of the first gearbox 4 and restrict further movement when the protective cover 50 (gearbox side holding portion 53) moves in the direction of the first gearbox 4.

[0067] As shown in FIG. 14, the box main body 53a is provided with a pair of left and right fitting recesses 57, 57 that are slidably fitted in the axial direction of the output shaft 6b (protective cover 50) with respect to the two fitting protrusions 29, 29 of the first gearbox 4 along the longitudinal direction on the inner surface sides of the opposite side walls 53g, 53g. Each of these fitting recesses 57, 57 is formed in a substantially V shape corresponding to each of the fitting protrusions 29, 29, and is formed to penetrate the rear end wall 53c from the stepped portion 53f.

[0068] Further, at the central position in the width direction between the both side walls 53g and 53g, an elastic claw 58 is integrally provided. As shown in FIGS. 9 and 14, this elastic claw 58 is formed in a substantially rectangular shape in a plan view along the front-rear direction of the protective cover 50, and a base end portion 58a is integrally coupled to the upper wall of a step portion 53f of the gear box side holding portion 53. Further, a claw portion 58c is provided on the lower surface of a tip end portion 58b to be locked to a locking surface 4d provided on an outer surface 4c of the first gear box 4 in the axial direction. The elastic claw 58 is elastically deformable in the vertical direction with the tip end portion 58b as a fulcrum with respect to the base end portion 58a. When the protective cover 50 is moved in the direction of the first gear box 4 in a state where the fitting recesses 57 and 57 are fitted to the fitting protrusions 29 and 29 from the axial direction, the claw portion 58c elastically slides on the upper surface of the first gear box 4 and is locked to the locking surface 4d, thereby restricting the movement of the protective cover 50 in the direction of the motor housing 6a. 〔Assembly procedure of the protective cover of the present embodiment〕 Next, based on FIGS. 16(a) to (d), the assembly procedure of the protective cover 50 in the present embodiment will be described. FIG. 16(a) is a side view showing an initial state in which the motor side holding portion of the protective cover is inserted into the motor housing in the axial direction, (b) is a side view showing a state in which the motor side holding portion is further gradually inserted in the same direction, (c) is a side view showing a state in which the motor side holding portion is inserted to the maximum in the same direction, and (d) is a side view showing a state in which the protective cover is pulled out in the opposite direction of the axial direction and the gear box side holding portion is fitted and fixed to the gear box.

[0069] In advance, each upper rail 2 is coupled to the lower portion of the vehicle seat, and the first and second gear boxes 4 and 5, an electric motor 6, etc. are attached between each lower rail 1 and each upper rail 2. Further, as shown in FIG. 1, both end portions 8c and 8d of the flexible shaft 8a of the transmission member 8 and both end portions of the outer tube 8b are inserted and connected to the worm 42 of the second gear box 5, the first cylindrical portion 18, and the worm 42 of the first gear box 4 and the second cylindrical portion 9, respectively.

[0070] In this state, first, hold the central portion 51 of the protective cover 50 and the gearbox-side holding portion 53 by hand, and arrange them to cover the transmission member 8 from above. Insert the motor-side holding portion 52 into the outer peripheral surface of the motor housing 6a from the side of the first cylindrical portion 18 from the front edge 52d side. Specifically, as shown by the white arrows in FIGS. 16(a) and 16(b), cover the motor-side holding portion 52 side of the protective cover 50 from obliquely above from the front edge 52 toward the first cylindrical portion 18, and insert it into the first cylindrical portion 18 from above through the insertion hole H, and at the same time, push it in the direction of the outer peripheral surface (right axis direction) of the motor housing 6a. That is, insert the motor-side holding portion 52 so as to cover the front end portion side of the first cylindrical portion 18 side of the motor housing 6a.

[0071] Thereafter, as shown by the white arrow in FIG. 16(c), when the protective cover 50 is further pushed into the maximum movement position in the coaxial direction (right axis direction), the gearbox-side holding portion 53 passes over the first gearbox 4 and moves to a position on the right side of the first gearbox 4.

[0072] Next, as shown by the white arrow in FIG. 16(d), pull the protective cover 50 so as to return it in the reverse direction from the maximum rightward movement position, and move the motor-side holding portion 52 leftward on the outer peripheral surface of the motor housing 6. At this time, the gearbox-side holding portion 53 slides leftward (rearward) in the drawing while the fitting concave portions 57, 57 are axially fitted to the fitting protrusions 29, 29 of the first gearbox 4 from the rear end wall 53c side, and the lower surface of the claw portion 58c of the elastic claw 58 elastically slides on the upper surface of the first gearbox 4. That is, the elastic claw 58 slides on the upper surface of the box body 4a of the first gearbox 4 while the tip portion 58b is elastically deformed upward with the base end portion 58a as a fulcrum and receiving an elastic reaction force.

[0073] When the stepped portion 53f of the gearbox-side holding portion 53 abuts against the inner side surface 4b of the first gearbox 4 and the maximum movement position is restricted, the claw portion 58c of the elastic claw 58 elastically returns and engages with the locking surface 4d on the outer side surface 4c of the first gearbox 4. As a result, in the drawing of FIG. 16(d), the protective cover 50 is restricted from moving in the left-right axial direction, and the motor-side holding portion 52 supports the motor housing 6a at four points by the upper two protrusions 54, 54 and the lower two end portions 52f, 52f.

[0074] As described above, according to the electric seat slide device of the present embodiment, the protective cover 50 is supported by sliding along the left-right axial direction of the output shaft 16 on the outer peripheral surface of the motor housing 6a. That is, since the protective cover 50 can be assembled only by sliding it in the left-right direction along the axial direction, the assembly work can be improved.

[0075] Further, since the motor-side holding portion 52 of the protective cover 50 is formed in a cylindrical shape corresponding to the outer peripheral surface of the motor housing 6a, the motor-side holding portion 52 can be inserted into the outer peripheral surface of the motor housing 6a from the axial direction. That is, since it can be applied to any electric motor 6 as long as the outer peripheral surface of the motor housing 6a is cylindrical, the structure of the protective cover 50 has high versatility.

[0076] Moreover, in the present embodiment, since the gearbox-side holding portion 53 of the protective cover 50 is coupled by sliding while the pair of fitting recesses 57, 57 are fitted into the pair of fitting protrusions 29, 29 of the first gearbox 4 from the axial direction, the reaction force against the upward load increases. That is, after the protective cover 50 is assembled, even if an upward pulling force acts on the gearbox-side holding portion 53, the fitting recesses 57, 57 are engaged with the fitting protrusions 29, 29, so that the upward detachment of the gearbox-side holding portion 53 can be sufficiently restricted. Therefore, a stable and strong coupling state between the first gearbox 4 and the gearbox-side holding portion 53 is ensured.

[0077] In addition, since the motor-side holding portion 52 of the protective cover 50 is formed in a tapered hole shape with a larger diameter on the front edge 52d side along the axial direction of the output shaft 6b of the electric motor 6, it becomes easier to insert it obliquely when assembling it to the motor housing 6a, and the assembling workability is improved.

[0078] After the protective cover 50 is assembled, the tip portions 54a, 54a of the pair of protrusions 54, 54 provided on the inner peripheral surface 52c of the motor-side holding portion 52 are in line contact with and support the outer peripheral surface of the motor housing 6a at this assembled position. As a result, the protective cover 50 can be stably supported on the outer peripheral surface of the motor housing 6a and the generation of play between the protective cover 50 and the outer peripheral surface of the motor housing 6a can be suppressed.

[0079] In particular, since the projecting heights of the two protrusions 54, 54 are formed so as to gradually decrease from the front edge 52d side along the inner axial direction contrary to the tapered shape of the inner peripheral surface 52c of the motor-side holding portion 52, when the motor-side holding portion 52 is inserted into the outer peripheral surface of the motor housing 6a, the tip portions 54a, 54a are in line contact with the outer peripheral surface of the motor housing 6a in the axial direction and can support it at the same height position in the vertical direction even if it moves in the axial direction. As a result, stable support without play by the motor-side holding portion 52 can be obtained.

[0080] Moreover, since both opposing end portions 52f, 52f of the motor-side holding portion 52 support the lower part of the outer peripheral surface of the motor housing 6a in a holding state by their own elastic force, in combination with the contact support of the two protrusions 54, 54, the outer peripheral surface of the motor housing 6a is supported at four points, so that the support is more stable and the generation of play can be sufficiently suppressed.

[0081] Further, according to the present embodiment, since the wall thickness T is gradually increased from both end portions 52f, 52f on the open side to the upper end portion 52e of the motor-side holding portion 52 of the protective cover 50 to increase the rigidity, the support rigidity of the motor-side holding portion 52 with respect to the motor housing 6a is increased. As a result, the reaction force of the motor-side holding portion 52 against the load in the direction of coming off upward from the motor housing 6a is increased, and the accidental detachment from the motor housing 6a can be restricted.

[0082] Furthermore, on the protective cover 50, the motor-side holding portion 52 side is inserted and supported axially into the motor housing 6a through the insertion hole H, and in the gearbox-side holding portion 53, the step portion 53f abuts against the inner surface 4b of the first gearbox 4 and the locking claw 58 locks to the locking surface 4d of the first gearbox 4, so that the entire protective cover 50 can be held stably and reliably.

[0083] Also, on the protective cover 50, a pair of protrusions 55, 55 are provided below the front edge 52d of the motor-side holding portion 52, and the contact area of the outer peripheral surface lower portion of the motor housing 6a by these both protrusions 55, 55 and both end portions 52f, 52f is increased, so that the support force for the motor housing 6a is increased. Therefore, in the protective cover 50, the reaction force in the upward direction on the motor-side holding portion 52 side is increased, and it will not easily come off even when an upward pulling force (load) is applied.

[0084] The present invention is not limited to the configuration of the above-described embodiment. For example, as the transmission member, a shaft other than the flexible shaft can be applied. Also, the electric seat slide device of the present invention can be used for vehicle seats other than vehicles. Further, in the electric seat slide device of the present invention, a gearbox is provided at the front end portion of the screw shaft and a structure for rotating the screw shaft is used, but it is also possible to apply it to a structure that covers a gearbox that fixes the screw shaft and rotates a nut member screwed to the screw shaft as described in Patent Document 1.

[0085] As an electric seat slide device based on the embodiment described above, for example, those in the following aspects can be considered.

[0086] As one aspect, in particular, the protective cover has, at one end on the side of the electric motor, a motor-side holding portion that is movably fitted in the axial direction of the output shaft on the outer peripheral surface of the motor housing and has an opening gap with an open lower portion, and at the other end on the side of the other gear box, a fitting recess that is slidably fitted in the axial direction of the output shaft with respect to a fitting protrusion provided at the upper end of the other gear box, and a regulation claw that regulates the movement of the output shaft of the electric motor in the axial direction in a state where the fitting recess is fitted to the fitting protrusion, and a gear box-side holding portion.

[0087] According to the present invention, since the protective cover is supported so as to be slidable along the axial direction of the output shaft on the outer peripheral surface of the motor housing, it can be assembled simply by sliding the protective cover in the left-right direction along the axial direction, so that the assembly work can be improved.

[0088] In addition, since the pair of fitting recesses of the gear box-side holding portion are fitted and slidably moved by fitting the pair of fitting protrusions formed on both side portions of the first gear box from the axial direction and joined, the reaction force against the upward pulling force of the gear box-side holding portion becomes large, the coupling force of the gear box-side holding portion to the gear box becomes high, and accidental detachment can be regulated.

[0089] Furthermore, since the motor-side holding portion of the protective cover is formed in a cylindrical shape, if the outer peripheral surface of the motor housing is formed in a cylindrical shape, the motor-side holding portion can be inserted into the outer peripheral surface from the axial direction. That is, since it can be applied to any electric motor as long as the outer peripheral surface of the motor housing is cylindrical, the versatility of the mounting structure of the protective cover is increased.

[0090] More preferably, the motor-side holding portion of the protective cover is formed in a substantially C shape with an open lower portion, and the inner peripheral surface is formed in a tapered shape that gradually increases in diameter from the inner part in the axial direction toward the front end edge on the motor housing side. A pair of protruding portions protruding toward the inner center are formed along the axial direction at predetermined angular positions on the left and right in the circumferential direction centered on the upper end of the inner peripheral surface. Each of the protruding portions is formed such that its height gradually decreases from the front end edge side toward the inside in the axial direction. According to the present invention, since the motor-side holding portion of the protective cover is formed in a tapered hole having a larger diameter on the outer end side along the axial direction of the output shaft of the electric motor, it becomes easier to insert it obliquely when assembling it to the motor-side housing, and the assemblability is improved.

[0091] Also, after assembling the protective cover, the tip portions of the pair of protruding portions provided on the inner peripheral surface of the motor-side holding portion abut and support the outer peripheral surface of the motor housing in a line contact state. As a result, the support of the motor housing by the protective cover is stabilized, and the generation of play between the protective cover and the outer peripheral surface of the motor housing can be suppressed.

[0092] More preferably, the motor-side holding portion is formed such that the wall thickness in the circumferential direction gradually increases from both end portions on the lower side facing each other between the opening gaps to the upper end portion in the circumferential direction. The motor-side holding portion is formed such that the reference radius of the inner peripheral surface passing through the tip of each protruding portion is slightly smaller than the outer diameter (radius) of the outer peripheral surface of the motor housing, and the inner peripheral surfaces at both end portions are formed smaller than the reference radius. The opposing both end portions support the lower portion of the outer peripheral surface of the motor housing at four points in the circumferential direction by the both protruding portions and the both end portions.

[0093] According to the present invention, by increasing the wall thickness from both end portions facing each other on the open side of the motor-side holding portion of the protective cover to the upper end portion to increase the rigidity, the support rigidity of the protective cover to the motor housing is increased. As a result, the protective cover has a greater reaction force against the load in the direction of coming off upward from the motor housing, and accidental detachment from the motor housing is suppressed.

[0094] Further, since both opposing end portions support and hold the lower portion of the outer peripheral surface of the motor housing by elastic force, in combination with the contact support of the two protruding portions, the outer peripheral surface of the motor housing is supported at four points, so that the support is more stable and the generation of rattling can be sufficiently suppressed.

[0095] More preferably, the motor-side holding portion is formed in a tubular shape along the longitudinal direction, the lower end portion is cut parallel to the longitudinal direction of the motor housing to form the opening gap, and the lower surface of the lower end portion of the motor-side holding portion is located above the lower end position of the motor housing.

[0096] According to this invention, the lower space of the motor housing can be secured by the lower end portion of the motor-side holding portion.

Explanation of Reference Numerals

[0097] 1…Lower rail, 2…Upper rail, 3…Screw shaft, 4…First gear box, 4a…Box body, 5…Second gear box, 6…Electric motor, 6a…Motor housing, 6b…Output shaft, 6c…Output shaft, 8…Transmission member, 8a…Flexible shaft, 8b…Outer tube, 9…Second cylindrical portion (gear box side cylindrical portion), 9a…Insertion hole, 18…First cylindrical portion (motor side cylindrical portion), 18a…Insertion hole, 29…Fitting protrusion, 50…Protective cover, 51…Central portion, 52…Motor-side holding portion (one end portion), 52a…Holding portion main body, 52c…Inner peripheral surface, 52d…Front edge, 52e…Upper end portion, 52f…Both end portions, 53…Gear box side holding portion (the other end portion), 53a…Box body, 53b…Connecting portion, 53c…Rear end portion, 54…Protruding portion, 55…Protrusion, 57…Fitting recess, 58…Regulating claw, 58a…Base end portion, 58b…Tip portion, 58c…Claw portion, H…Insertion hole.

Claims

1. A pair of left and right rail assemblies arranged along the longitudinal direction of the vehicle body on both left and right sides of a vehicle seat includes a pair of lower rails fixed to the vehicle floor, a pair of upper rails slidably attached to the pair of lower rails and to which a vehicle seat is attached, a pair of screw shafts rotatably disposed inside between each upper rail and each lower rail, with male threads formed on their respective outer circumferences, a pair of nut members fixed to each lower rail and having female screw holes into which the male threads of each screw shaft are screwed, a pair of gear boxes fixed to each upper rail and each having a gear mechanism for rotationally driving either one of each screw shaft and each nut member, an electric motor disposed between the pair of upper rails and fixed to the one gear box fixed to one of the upper rails, a transmission member connecting the output shaft of the electric motor and the input shaft of the gear mechanism in the other gear box fixed to the other upper rail, a cylindrical motor housing extending along the axial direction of the output shaft of the electric motor, a motor-side cylindrical portion provided at one end of the motor housing on the other gear box side and into which one end portion of the transmission member can be inserted, a gear-box-side cylindrical portion provided in the other gear box, facing the first cylindrical portion in the axial direction and into which the other end portion of the transmission member can be inserted, a protective cover extending between the motor housing and the other gear box and covering the transmission member, the motor-side cylindrical portion, and the gear-box-side cylindrical portion from above with its lower surface open, and comprising the protective cover has, at one end on the electric motor side, a cylindrical motor-side holding portion having an opening gap that fits movably in the axial direction of the output shaft on the outer peripheral surface of the motor housing and has an open lower portion, and, at the other end on the other gear box side, a gear-box-side holding portion having a fitting recess that fits slidably in the axial direction of the output shaft with respect to a fitting projection provided at the upper end of the other gear box, and having a regulating claw that regulates movement in the axial direction of the output shaft in a state where the fitting recess fits into the fitting projection. An electric seat slide device characterized by this.

2. The electric seat slide device according to claim 1, The motor-side holding portion of the protective cover is formed in a substantially C shape with an open bottom, and the inner peripheral surface is formed in a tapered shape that gradually increases in diameter from the inner part in the axial direction toward the front end edge on the motor housing side. A pair of protruding portions that protrude toward the inner center are formed along the axial direction at predetermined angular positions on the left and right in the circumferential direction centered on the upper end of the inner peripheral surface. Each of the protruding portions is characterized in that its height is gradually decreased from the front end edge side toward the inside in the axial direction. An electric seat slide device.

3. The electric seat slide device according to claim 2, wherein the motor-side holding portion is formed such that the wall thickness in the circumferential direction gradually increases from both end portions on the lower side facing each other between the opening gaps to the upper end portion in the circumferential direction. The motor-side holding portion is formed such that the reference radius of the inner peripheral surface passing through the tips of the pair of protruding portions is slightly smaller than the radius of the outer peripheral surface of the motor housing, and the radii of the inner peripheral surfaces of both end portions are further smaller than the reference radius. The electric seat slide device is characterized in that the opposing both end portions support the lower part of the outer peripheral surface of the motor housing at four points in the circumferential direction by the both protruding portions and the both end portions.

4. The electric seat slide device according to claim 1, wherein the motor-side holding portion is formed in a cylindrical shape along the longitudinal direction, and the lower end portion is cut parallel to the longitudinal direction of the motor housing to form the opening gap. The electric seat slide device is characterized in that the lower surface of the lower end portion of the motor-side holding portion is located above the lower end position of the motor housing.

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