Description SEAT TRACK FOR VEHICLE

Technical Field

[1] The present invention relates, in general, to a seat track for vehicle, and more particularly, to a seat track for vehicle, in which taper plates of a position adjustment rail extend from ends of side walls of the position adjustment rail and are bent in outward directions, thereby increasing transverse rigidity, and in which second curvatures and side walls of the position adjustment rail are in contact with each other, thereby preventing longitudinal torsion of the position adjustment rail, as well as increasing transverse and longitudinal rigidities of the position adjustment rail. Background Art

[2] In general, the seat of a vehicle is provided with a plurality of apparatuses that can be adjusted to be suitable for the body size of the person sitting in the seat. For example, the apparatuses includes a seat position adjustment apparatus for moving both a seat cushion and a seatback backwards and forwards, a height and angle adjustment apparatus for adjusting the height of the seat cushion and the inclination angle of the seatback, and a rotation apparatus for rotating the seat in a plane so as to enable the occupant to face toward the side or back.

[3] FIG. 1 is a perspective view showing the state in which an ordinary seat track is coupled to a seat. FIG. 2 is a sectional view showing a construction of a conventional seat track for vehicle. FIG. 3 is a partial sectional view of FIG. 2. FIG. 4 is a sectional view showing a construction of another conventional seat track for vehicle.

[4] As in FIG. 1 showing the state in which an ordinary seat track is coupled to a seat, a seat position adjustment apparatus 6, which has a seat track 2, a seat locking unit 4, etc., serves to move a driver or passenger seat 10 backwards and forwards so as to enable an occupant such as a driver or passenger to sit on the seat in comfort. In particular, the driver adjusts the seat position adjustment apparatus 6 according to his/ her body size, and thereby can drive the vehicle in a comfortably seated state.

[5] Meanwhile, as shown in FIG. 2, a "universal seat track assembly" disclosed in US

Patent No. 6557809 (May 6, 2003) includes a first track having a mounting wall and side walls extending along the mounting wall, and a second track, movable relative to the first track, wherein the second track 30 has a base flange 31 and side flanges 32 extending along the base flange 31 , wherein the first side wall 22 has first and second surfaces 26 and 27, the first side flange 32 has third and fourth surfaces 33 and 34, and the first, second, third, and fourth surfaces 26, 27, 33, and 34 cooperate to define a load transmission channel 40, and at least one load transmission element 42 is located

within the load transmission channel 40, wherein at least one of the first track 20 and the second track 30 is configured to produce interference between the at least one load transmission element 42 and at least one of the first and second tracks 20 and 30 so that at least one of the first and second tracks 20 and 30 is elastically displaced at the time of assembly by the at least one transmission element 42 to preload the at least one load transmission element 42 to make it engage with each of the first, second, third, and fourth surfaces 26, 27, 33, and 34 when the seat track assembly 50 is in an unloaded condition.

[6] This seat track assembly 50 is configured to have a connecting web 23 so as to be perpendicular to the side wall 22, and a side leg 28 that extends from the connecting web 23 and has first and second leg portions 24 and 25 that are perpendicular to each other. In the state in which the load transmission element 42 is fitted into a load transmission channel 40 formed by the first and second tracks 20 and 30, as shown in FIG. 3, the first and second leg portions 24 and 25 of each side leg 28 are supplied with pressing force by means of the load transmission element 42, and the pressing force is transmitted in a and b directions.

[7] As described above, the conventional seat track assembly 50 has a drawback in that the transverse rigidity is weak because the pressing force is transmitted only in the a and b directions, and a problem in that, because the pressing force is transmitted only in the a and b directions, the amount of flexure is maximized in the a and b directions, and thereby the fatigue on the first track is increased.

[8] Further, the conventional seat track assembly 50 has another problem in that, when the first track 20 is transferred so as to move the seat backwards and forwards, the side leg 28 of the first track 20 undergoes longitudinal torsion against the side wall 22 by means of the road transmission element 42 that is in frictional contact with the first and second surfaces 26 and 27 of the side wall 22.

[9] In addition, due to the inertial force that acts on the seat to move it toward the front of the vehicle when the vehicle suddenly stops or is in a collision, the external force is applied to the first track in an upward direction. In this manner, when the external force is applied to the first track in an upward direction, the side flange 32 of the second track 30 easily moves in an outward direction. This compromises the safety of the occupant.

[10] Meanwhile, as in FIG. 4 showing a construction of another conventional seat track, a "sheet track for vehicle" disclosed in Korean Patent Publication No. 2001-0084981 (September 7, 2001), filed by the applicant of this invention, includes a fixing rail 70, a position adjustment rail 60, and balls 80.

[11] The fixing rail 70 is provided with a bead 71 a in the middle of one side thereof, and includes vertical pieces 72 that are vertically bent on opposite sides of a fixing piece 71

in which a plurality of hooking slots 71b is arranged at regular intervals in the middle of the bead 71a, curvatures 73 by which the middle of each vertical piece 72 bulges in an outward direction so as to allow the balls to be inserted, and J-shaped finishing pieces 74 that are vertically bent at ends of the vertical pieces 72 in a downward direction.

[12] The position adjustment rail 60 includes a seat fixture 61 on an upper surface of which a seat is coupled with a width slightly narrower than that of the fixing rail 70, side walls 62 that are vertically bent on opposite ends of the seat fixture 61 in a downward direction, curvatures 63 that are bent in a U shape at ends of the side walls 62 in outward directions so as to allow the balls to be inserted at the same positions as the curvatures 73 of the fixing rail, and flanges 64 that are finishing portions of the curvatures 63.

[13] Meanwhile, the balls 80 are inserted between the curvatures 73 of the fixing rail 70 and the curvatures 63 of the position adjustment rail 60, and thus allow the position adjustment rail 60 to move inside the fixing rail 70 in a point contact manner.

[14] Like the conventional seat track assembly 50, the sheet track for vehicle having the above-described structure has a drawback in that the transverse rigidity is weak because pressing force is transmitted only in c and d directions, and a problem in that, because the pressing force is transmitted only in the c and d directions, the amount of flexure is maximized in the c and d directions. Further, the sheet track for vehicle has another problem in that, when the first track 20 is moved in order to move the seat backwards and forwards, the curvatures 63 of the position adjustment rail 60 cause longitudinal torsion against the side walls 62 through the balls 80, which are in frictional contact with the curvatures 63 of the position adjustment rail 60. Disclosure of Invention Technical Problem

[15] Accordingly, the present invention has been made in an effort to solve the problems occurring in the related art, and an object of the present invention is to provide a seat track for vehicle, in which taper plates of a position adjustment rail extend from ends of side walls of the position adjustment rail and bend in outward directions, thereby increasing transverse rigidity, and in which second curvatures and side walls of the position adjustment rail are in contact with each other, thereby preventing longitudinal torsion of the position adjustment rail, as well as increasing transverse and longitudinal rigidities of the position adjustment rail. Technical Solution

[16] In order to achieve the above object, according to one aspect of the present invention, provided is a seat track for vehicle, which includes a fixing rail that is fixed

on the bottom surface of the vehicle passenger compartment, a position adjustment rail that is coupled into the fixing rail so as to be moved backwards and forwards with a seat coupled on an upper surface thereof, and sliding members that are interposed between the fixing rail and the position adjustment rail so as to allow the position adjustment rail to be smoothly moved.

[17] The fixing rail includes first bends that extend from opposite ends of a fixing plate, which is fixed on the bottom surface of the vehicle passenger compartment and are bent in upward directions; first curvatures that extend from the first bends and bulge in outward directions; first vertical plates that vertically extend from ends of the first curvatures; horizontal plates that horizontally extend from ends of the first vertical plates and are bent in inward directions; and second vertical plates that extend from ends of the horizontal plates and bend in downward vertical directions.

[18] The position adjustment rail includes side walls that extend from opposite ends of a seat fixing plate, on an upper surface of which the seat is coupled, and are bent in downward vertical directions; taper plates that extend from ends of the side walls and are bent in outward directions at a predetermined angle; second bends that extend from the taper plates and are bent in upward directions; second curvatures that extend from the second bends and bulge in inward directions; and third vertical plates that extend from ends of the second curvatures in upward vertical directions.

[19] The sliding members are fitted between the first curvatures of the fixing rail and the second curvatures of the position adjustment rail.

[20] According to another aspect of the present invention, the second curvatures may be in contact with the side walls.

[21] According to another aspect of the present invention, the angle of the taper plates that are bent at the ends of the side walls in outward directions may be an acute angle.

[22] According to another aspect of the present invention, the third vertical plates of the position adjustment rail may be partly located in spaces that are defined by the first vertical plates, the horizontal plates, and second vertical plates of the fixing rail.

[23] According to another aspect of the present invention, there is provided a seat track for vehicle, which includes a fixing rail that is fixed on the bottom surface of the vehicle passenger compartment, a position adjustment rail that is coupled into the fixing rail so as to be movable backwards and forwards with a seat coupled on an upper surface thereof, and sliding members that are interposed between the fixing rail and the position adjustment rail so as to allow the position adjustment rail to be smoothly moved.

[24] The fixing rail includes first bends that extend from opposite ends of a fixing plate, which is fixed on the bottom surface of the vehicle passenger compartment, and are bent in upward directions; first curvatures that extend from the first bends and bulge in

outward directions; first vertical plates that vertically extend from ends of the first curvatures; horizontal plates that horizontally extend from ends of the first vertical plates and are bent in inward directions; and second vertical plates that extend from ends of the horizontal plates and are bent in downward vertical directions.

[25] The position adjustment rail includes a first position adjustment rail and a second position adjustment rail.

[26] The first position adjustment rail includes an L-shaped bracket that extends from the end of a first vertical coupling plate having a plurality of coupling holes, a first taper plate that extends from an end of the L-shaped bracket and is bent in an outward direction at a predetermined angle; a third bend that extends from the first taper plate and is bent in an upward direction; a third curvature that extends from the third bend and bulges in an inward direction; and a fourth vertical plate that extends from an end of the third curvature in an upward vertical direction.

[27] The second position adjustment rail includes a second taper plate that extends from a lower end of a second vertical coupling plate having a plurality of coupling holes and is bent in an outward direction at a predetermined angle; a fourth bend that extends from the second taper plate and is bent in an upward direction; a fourth curvature that extends from the fourth bend and bulges in an inward direction; and a fifth vertical plate that extends from an end of the fourth curvature in an upward vertical direction.

[28] Both the first position adjustment rail and the second position adjustment rail are coupled with the seat by means of fastening means passing through the coupling holes of the first position adjustment rail and the coupling holes of the second position adjustment rail at the same time in the state in which the first vertical coupling plate of the first position adjustment rail is in contact with the second vertical coupling plate of the second position adjustment rail. The sliding members are fitted between one of the first curvatures of the fixing rail and the third curvature of the first position adjustment rail and between the other first curvature of the fixing rail and the fourth curvature of the second position adjustment rail, respectively.

[29] According to another aspect of the present invention, the third curvature may be in contact with the L-shaped bracket, and the fourth curvature may be in contact with the second vertical coupling plate.

[30] According to another aspect of the present invention, both the angle of the first taper plate that is bent at the end of the L-shaped bracket in an outward direction and the angle of the second taper plate that is bent at the lower end of the second vertical coupling plate in an outward direction may be acute angles.

[31] According to another aspect of the present invention, the fourth vertical plate and fifth vertical plate of the position adjustment rail may be partly located in spaces that are defined by the first vertical plates, horizontal plates, and second vertical plates of

the fixing rail, respectively.

Advantageous Effects

[32] According to the seat track for vehicle of the present invention, the taper plates of the position adjustment rail extend from the ends of side walls of the position adjustment rail and are bent in outward directions, so that the transverse rigidity is increased. The pressing force from each sliding member is dispersed in various directions, and thus the degree of fatigue of the position adjustment rail is lowered.

[33] Further, the second curvatures and side walls of the position adjustment rail are in contact with each other, so that longitudinal torsion of the position adjustment rail can be prevented, and transverse and longitudinal rigidities of the position adjustment rail are increased.

[34] Furthermore, the third vertical plates of the position adjustment rail are partly located in spaces that are defined by the first vertical plates, horizontal plates, and second vertical plates of the fixing rail, so that the sliding members are not separated even though a force from the fixing rail is applied to the position adjustment rail in an upward direction.

[35] In addition, a coupled portion of the seat coupled with the position adjustment rail is horizontally fastened with the first and second vertical coupling plates of the position adjustment rail, so that horizontal assemblability of the seat track and the seat is improved, and thus the workability of the seat is improved. Further, the degree of freedom of layout of a seat frame is increased, and thus the production cost of the seat can be reduced. Brief Description of the Drawings

[36] The above objects, and other features and advantages of the present invention will become more apparent after a reading of the following detailed description when taken in conjunction with the drawings, in which:

[37] FIG. 1 is a perspective view showing the state in which an ordinary seat track is coupled to a seat;

[38] FIG. 2 is a sectional view showing a construction of a conventional seat track for vehicle;

[39] FIG. 3 is a partial sectional view of FIG. 2;

[40] FIG. 4 is a sectional view showing a construction of another conventional seat track for vehicle;

[41] FIG. 5 is a perspective view showing a construction of a seat track for vehicle according to a first embodiment of the present invention;

[42] FIG. 6 is a sectional view taken along the line A-A of FIG. 5;

[43] FIG. 7 is an exploded perspective view showing a construction of a seat track for

vehicle according to a first embodiment of the present invention; [44] FIG. 8 is a partial sectional view of FIG. 6;

[45] FIG. 9 is a perspective view showing a construction of a seat track for vehicle according to a second embodiment of the present invention; [46] FIG. 10 is a sectional view taken along the line B-B of FIG. 9;

[47] FIG. 11 is an exploded perspective view showing a construction of a seat track for vehicle according to a second embodiment of the present invention; [48] FIG. 12 is a partial sectional view of FIG. 10;

[49] FIG. 13 is a perspective view showing a construction of a seat track for vehicle according to a third embodiment of the present invention; [50] FIG. 14 is a sectional view taken along the line C-C of FIG. 13;

[51] FIG. 15 is an exploded perspective view showing a construction of a seat track for vehicle according to a third embodiment of the present invention; [52] FIG. 16 is a partial sectional view of FIG. 14;

[53] FIG. 17 is a perspective view showing a construction of a seat track for vehicle according to a fourth embodiment of the present invention; [54] FIG. 18 is a sectional view taken along the line D-D of FIG. 17;

[55] FIG. 19 is an exploded perspective view showing a construction of a seat track for vehicle according to a fourth embodiment of the present invention; [56] FIG. 20 is a partial sectional view of FIG. 18.

Best Mode for Carrying Out the Invention [57] Reference will now be made in greater detail to exemplary embodiments of the invention with reference to the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. [58] A first embodiment of the present invention will be described with reference to

FIGS. 5 through 8. [59] FIG. 5 is a perspective view showing a construction of a seat track for vehicle according to a first embodiment of the present invention. FIG. 6 is a sectional view taken along the line A-A of FIG. 5. FIG. 7 is an exploded perspective view showing a construction of a seat track for vehicle according to a first embodiment of the present invention. FIG. 8 is a partial sectional view of FIG. 6. [60] The seat track for vehicle according to a first embodiment thereof is generally composed of a fixing rail 100, a position adjustment rail 200, and sliding members

300, and the position adjustment rail 200 thereof is moved backwards and forwards by the manipulation of an occupant in the state in which the fixing rail 100 is fixed on the bottom surface of the vehicle passenger compartment.

[61] As shown in FIGS. 5 and 7, the fixing rail 100 is a lengthwise member, and includes first bends 120 that extend from opposite ends of a fixing plate 110, which is fixed on the bottom surface of the vehicle passenger compartment, and are bent in an upward directions; first curvatures 130 that extend from the first bends 120 and bulge in outward directions; first vertical plates 140 that vertically extend from ends of the first curvatures 130; horizontal plates 150 that horizontally extend from ends of the first vertical plates 140 and are bent in inward directions; and second vertical plates 160 that extend from ends of the horizontal plates 150 and are bent in downward vertical directions.

[62] As shown in FIGS. 5 and 7, the position adjustment rail 200 is a lengthwise member, and includes side walls 220 that extend from opposite ends of a seat fixing plate 210, on an upper surface of which a seat 10 is coupled, and are bent in downward vertical directions; taper plates 230 that extend from ends of the side walls 220 and are bent in outward directions at a predetermined angle α (FIG. 8); second bends 240 that extend from the taper plates 230 and are bent in upward directions; second curvatures 250 that extend from the second bends 240 and bulge in inward directions; and third vertical plates 260 that extend from ends of the second curvatures 250 in upward vertical directions.

[63] At this time, the angle α of the taper plates 230 that are bent at the ends of the side walls 220 in outward directions is preferably an acute angle.

[64] As described above, because the taper plates 230 bent at an acute angle extend from the ends of the side walls 220 of the position adjustment rail 200 in outward directions, when pressing forces from the sliding members 300 are transmitted to the second curvatures 250, as shown in FIG. 8, in the state in which the sliding members 300 are fitted between the fixing rail 100 and the position adjustment rail 200, the pressing forces are dispersed in directions e, f, and g, and thus the transverse rigidity is increased compared to the conventional seat track.

[65] Meanwhile, as shown in FIG. 6, ends of the third vertical plate 260 of the position adjustment rail 200 are preferably located in the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100.

[66] Due to this structure, in which the ends of the third vertical plates 260 of the position adjustment rail 200 further enter into the spaces defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, namely, in which the C-shaped spaces, defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, enclose the third vertical plates 260 of the position adjustment rail 200, even if external force is applied upwards to the position adjustment rail 200, the position adjustment rail 200 is

prevented from escaping from the fixing rail 100. Further, if the first vertical plates 140 move in outward directions, the third vertical plates 260 of the position adjustment rail 200 are caught in the second vertical plates 160 of the fixing rail 100. As a result, the movement of the first vertical plates 140 is restricted, and thus separation of the sliding members 300 can be prevented.

[67] Meanwhile, as shown in FIGS. 5 and 6, the sliding members 300 are fitted between the first curvatures 130 of the fixing rail 100 and the second curvatures 250 of the position adjustment rail 200, and thus the position adjustment rail 200 is smoothly moved.

[68] At this time, the sliding members 300 can be selected from among components such as a ball bearing, a roller, a slider, etc., that allow the position adjustment rail 200 to slide.

[69] Therefore, when the position adjustment rail 200 is transferred backwards and forwards, the seat, fixed to the seat fixing plate 210 of the position adjustment rail 200, is moved backwards and forwards.

[70] Next, a second embodiment of the present invention will be described with reference to FIGS. 9 through 12.

[71] FIG. 9 is a perspective view showing the construction of a seat track for vehicle according to a second embodiment of the present invention. FIG. 10 is a sectional view taken along the line B-B of FIG. 9. FIG. 11 is an exploded perspective view showing the construction of a seat track for vehicle according to the second embodiment of the present invention. FIG. 12 is a partial sectional view of FIG. 10.

[72] The seat track for vehicle according to the second embodiment is generally composed of a fixing rail 100, a position adjustment rail 200, and sliding members 300, and the position adjustment rail 200 thereof is moved backwards and forwards by the manipulation of an occupant in the state in which the fixing rail 100 is fixed on the bottom surface of the vehicle passenger compartment. At this time, second curvatures 250 of the position adjustment rail 200 are in contact with side walls 220 of the position adjustment rail 200.

[73] Meanwhile, in the seat track for vehicle according to the first embodiment, the fixing rail 100 and sliding members 300 thereof are the same as those of the seat track for vehicle according to the second embodiment, while only the position adjustment rail 200 thereof is different from that of the seat track for vehicle according to the second embodiment. Hence, the fixing rail 100 and sliding members 300 of the seat track for vehicle according to the second embodiment will not be described.

[74] As shown in FIGS. 9 and 11, the position adjustment rail 200 is a lengthwise member, and includes side walls 220 that extend from opposite ends of a seat fixing plate 210, on an upper surface of which a seat 10 is coupled, and are bent in downward

verticals directions; taper plates 230 that extend from ends of the side walls 220 and are bent in outward directions at a predetermined angle α' (FIG. 10); second bends 240 that extend from the taper plates 230 and are bent in an upward direction; second curvatures 250 that extend from the second bends 240 and bulge in inward directions; and third vertical plates 260 that extend from ends of the second curvatures 250 in upward vertical directions.

[75] At this time, as shown in FIG. 10, preferably, the angle α' of the taper plates 230 that are bent at the ends of the side walls 220 in outward directions is an acute angle, and the second curvatures 250 of the position adjustment rail 200 are in contact with the side walls 220 of the position adjustment rail 200.

[76] As for the structure in which the taper plates 230, bent at an acute angle, extend from the ends of the side walls 220 of the position adjustment rail 200 in outward directions, when pressing forces from the sliding members 300 are transmitted to the second curvatures 250, as shown in FIG. 12, the pressing forces are dispersed in h, i, and j directions, wherein a dual structure exists in the h direction in which the second curvature 250 and side wall 220 of the position adjustment rail 200 are in contact with each other at a contact point Pl, and another dual structure exists in the i and j directions in which the second curvature 250 and taper plate 230 of the position adjustment rail 200 overlap each other a predetermined amount. This structure serves to provide reinforcement, and thus the transverse rigidity is increased.

[77] Further, because the second curvature 250 and side wall 220 of the position adjustment rail 200 are in contact with each other along the contact point Pl in a longitudinal direction, the position adjustment rail 200 can be prevented from generating torsion in a longitudinal direction by means of the frictional force of the sliding member 300, which is in contact with the second curvature 250 of the position adjustment rail 200 when moved, so as to move the seat backwards and forwards, and thus transverse and longitudinal rigidities of the position adjustment rail 200 are increased.

[78] Meanwhile, as shown in FIG. 10, ends of the third vertical plate 260 of the position adjustment rail 200 are preferably located in the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100.

[79] Due to this structure, in which the ends of the third vertical plates 260 of the position adjustment rail 200 enter into the spaces defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, that is, in which the C-shaped spaces, defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, enclose the third vertical plates 260 of the position adjustment rail 200, even if external force is applied upwards

to the position adjustment rail 200, the position adjustment rail 200 is prevented from escaping from the fixing rail 100. Further, if the first vertical plates 140 move in an outward direction, the third vertical plates 260 of the position adjustment rail 200 are caught in the second vertical plates 160 of the fixing rail 100. As a result, the movement of the first vertical plates 140 is restricted, and thus separation of the sliding members 300 can be prevented.

[80] Now, a third embodiment of the present invention will be described with reference to FIGS. 13 through 16.

[81] FIG. 13 is a perspective view showing the construction of a seat track for vehicle according to a third embodiment of the present invention. FIG. 14 is a sectional view taken along line C-C of FIG. 13. FIG. 15 is an exploded perspective view showing the construction of a seat track for vehicle according to a third embodiment of the present invention. FIG. 16 is a partial sectional view of FIG. 14.

[82] The seat track for vehicle according to a third embodiment is generally composed of a fixing rail 100, a position adjustment rail 400, and sliding members 300, wherein the position adjustment rail 400 includes a first position adjustment rail 410 and a second position adjustment rail 460. The seat track moves the position adjustment rail 400 backwards and forwards by means of manipulation of an occupant in the state in which the fixing rail 100 is fixed on the bottom surface of the vehicle passenger compartment.

[83] Meanwhile, in the seat track for vehicle according to the first or second embodiment, the fixing rail 100 and sliding members 300 thereof are the same as those of the seat track for vehicle according to the third embodiment, while only the position adjustment rail 200 thereof is different from that of the seat track for vehicle according to the third embodiment. Hence, the fixing rail 100 and sliding members 300 of the seat track for vehicle according to the third embodiment will not be described.

[84] As shown in FIGS. 13 and 15, the position adjustment rail 400 is a lengthwise member, and is composed of the first and second position adjustment rails 410 and 460.

[85] The first position adjustment rail 410 includes an L-shaped bracket 414 that extends from the end of a first vertical coupling plate 412 having a plurality of coupling holes 412h, a first taper plate 416 that extends from an end of the L-shaped bracket 414 and is bent in an outward direction at a predetermined angle β (FIG. 14); a third bend 418 that extends from the first taper plate 416 and is bent in an upward direction; a third curvature 420 that extends from the third bend 418 and bulges in an inward direction; and a fourth vertical plate 422 that extends from an end of the third curvature 420 in an upward vertical direction.

[86] The second position adjustment rail 460 includes a second taper plate 466 that

extends from the lower end of a second vertical coupling plate 462 having a plurality of coupling holes 462h and is bent in an outward direction at a predetermined angle β' (FIG. 14); a fourth bend 468 that extends from the second taper plate 466 and is bent in an upward direction; a fourth curvature 470 that extends from the fourth bend 468 and bulges in an inward direction; and a fifth vertical plate 472 that extends from an end of the fourth curvature 470 in an upward vertical direction.

[87] The first and second position adjustment rails 410 and 460 are coupled with the seat by means of fastening means, such as a bolt and nut, passing through both the coupling holes 412h and 462h thereof in the state in which the first vertical coupling plate 412 of the first position adjustment rail 410 is in contact with the second vertical coupling plate 462 of the second position adjustment rail 460.

[88] At this time, as shown in FIG. 14, preferably, both the angle β of the first taper plate

416, which is bent at the end of the L-shaped bracket 414 in an outward direction, and the angle β' of the second taper plate 466, which is bent at the lower end of the second vertical coupling plate 462 in an outward direction, are acute angles.

[89] As for the structure in which the first taper plate 416 is bent at the end of the L- shaped bracket 414 in an outward direction at an acute angle, when pressing force from the right-hand sliding member 300 is transmitted to the third curvature 420 as shown in FIG. 16, the pressing force is dispersed in e', f , and g' directions, and thus the transverse rigidity is increased compared to the conventional seat track. This is also true of the structure in which the second taper plate 466 is bent at the lower end of the second vertical coupling plate 462 in an outward direction at an acute angle, and thus a description thereof will be omitted.

[90] Meanwhile, as shown in FIG. 14, ends of the fourth and fifth vertical plates 422 and

472 of the position adjustment rail 400 are preferably located in the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, respectively.

[91] Due to this structure, in which the ends of the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 enter into the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100 respectively, that is, in which the C-shaped spaces, defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, enclose the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400, even if external force is applied upwards to the position adjustment rail 400, the position adjustment rail 400 is prevented from escaping from the fixing rail 100. Further, if the first vertical plates 140 are moved in outward directions, the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 are caught in the second vertical plates 160 of the fixing rail 100. As a result,

the movement of the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 are restricted, and thus separation of the sliding members 300 can be prevented.

[92] Further, due to the structure in which the first and second position adjustment rails

410 and 460 are coupled with the seat by means of fastening means, such as a bolt and nut, passing through the coupling holes 412h and 462h thereof at the same time in the state in which the first vertical coupling plate 412 of the first position adjustment rail 410 is in contact with the second vertical coupling plate 462 of the second position adjustment rail 460, the assemblability of the seat track and the seat is improved.

[93] Subsequently, a fourth embodiment of the present invention will be described with reference to FIGS. 17 through 20.

[94] FIG. 17 is a perspective view showing the construction of a seat track for vehicle according to a fourth embodiment of the present invention. FIG. 18 is a sectional view taken along the line D-D of FIG. 17. FIG. 19 is an exploded perspective view showing the construction of a seat track for vehicle according to a fourth embodiment of the present invention. FIG. 20 is a partial sectional view of FIG. 18.

[95] The seat track for vehicle according to a fourth embodiment is generally composed of a fixing rail 100, a position adjustment rail 400, and sliding members 300, wherein the position adjustment rail 400 includes a first position adjustment rail 410 and a second position adjustment rail 460. The seat track moves the position adjustment rail 400 backwards and forwards by means of manipulation of an occupant in the state in which the fixing rail 100 is fixed on the bottom surface of the vehicle passenger compartment. At this time, a second curvature 420 of the first position adjustment rail 410 is in contact with an L-shaped bracket 414 of the first position adjustment rail 410, and a third curvature 470 of the second position adjustment rail 460 is in contact with a second vertical coupling plate 462 of the second position adjustment rail 460.

[96] Meanwhile, in the seat track for vehicle according to the first, second or third embodiment, the fixing rail 100 and sliding members 300 thereof are the same as those of the seat track for vehicle according to the third embodiment, while only the position adjustment rail 200 (or 400) thereof is different from that of the seat track for vehicle according to the fourth embodiment. Hence, the fixing rail 100 and sliding members 300 of the seat track for vehicle according to the fourth embodiment will not be described.

[97] As shown in FIGS. 17 and 19, the position adjustment rail 400 is a lengthwise member, and is composed of the first and second position adjustment rails 410 and 460.

[98] The first position adjustment rail 410 includes an L-shaped bracket 414 that extends from the end of a first vertical coupling plate 412 having a plurality of coupling holes

412h, a first taper plate 416 that extends from an end of the L-shaped bracket 414 and is bent in an outward direction at a predetermined angle γ (FIG. 18); a third bend 418 that extends from the first taper plate 416 and is bent in an upward direction; a third curvature 420 that extends from the third bend 418 and bulges in an inward direction; and a fourth vertical plate 422 that extends from an end of the third curvature 420 in an upward vertical direction.

[99] The second position adjustment rail 460 includes a second taper plate 466 that extends from a lower end of a second vertical coupling plate 462 having a plurality of coupling holes 462h and is bent in an outward direction at a predetermined angle γ' (FIG. 18); a fourth bend 468 that extends from the second taper plate 466 and is bent in an upward direction; a fourth curvature 470 that extends from the fourth bend 468 and bulges in an inward direction; and a fifth vertical plate 472 that extends from an end of the fourth curvature 470 in an upward vertical direction.

[100] The first and second position adjustment rails 410 and 460 are coupled with the seat by means of fastening means, such as a bolt and nut, passing through the coupling holes 412h and 462h thereof at the same time in the state in which the first vertical coupling plate 412 of the first position adjustment rail 410 is in contact with the second vertical coupling plate 462 of the second position adjustment rail 460.

[101] At this time, as shown in FIG. 18, preferably, both the angle γ of the first taper plate

416, which is bent at the end of the L-shaped bracket 414 in an outward direction, and the angle γ' of the second taper plate 466, which is bent at the lower end of the second vertical coupling plate 462 in an outward direction, are acute angles. The third curvature 420 is preferably in contact with the L-shaped bracket 414, and the fourth curvature 470 is preferably in contact with the second vertical coupling plate 462.

[102] As for the structure in which the first taper plate 416 is bent at the end of the L- shaped bracket 414 in an outward direction at an acute angle, when pressing force from the right-hand sliding member 300 is transmitted to the third curvature 420 as shown in FIG. 20, the pressing force is dispersed in h', i', and j' directions, wherein a dual structure exists in the h' direction in which the third curvature 420 and L-shaped bracket 414 of the first position adjustment rail 410 are in contact with each other at a contact point P2, and another dual structure exists in the i' and j' directions in which the third curvature 420 and first taper plate 416 of the first position adjustment rail 410 overlap each other a predetermined amount. This structure serves to provide reinforcement, and thus the transverse rigidity is increased. This is also true of the structure in which the second taper plate 466 is bent at the lower end of the second vertical coupling plate 462 in an outward direction at an acute angle, and thus a description thereof will be omitted.

[103] Meanwhile, as shown in FIG. 18, ends of the fourth and fifth vertical plates 422 and

472 of the position adjustment rail 400 are preferably located in the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, respectively.

[104] Due to this structure, in which the ends of the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 enter into the spaces that are defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100 respectively, that is, in which the C-shaped spaces, defined by the first vertical plates 140, horizontal plates 150, and second vertical plates 160 of the fixing rail 100, enclose the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400, although external force is applied upwards to the position adjustment rail 400, the position adjustment rail 400 is prevented from escaping from the fixing rail 100. Further, even if the first vertical plates 140 are moved in outward directions, the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 are caught in the second vertical plates 160 of the fixing rail 100. As a result, the movement of the fourth and fifth vertical plates 422 and 472 of the position adjustment rail 400 is restricted, and thus separation of the sliding members 300 can be prevented.

[105] Further, due to the structure in which the first and second position adjustment rails

410 and 460 are coupled with the seat by a fastening means, such as a bolt and nut, passing through the coupling holes 412h and 462h thereof at the same time in the state in which the first vertical coupling plate 412 of the first position adjustment rail 410 is in contact with the second vertical coupling plate 462 of the second position adjustment rail 460, the assemblability of the seat track and the seat is improved.

[106] In the drawings and specification, typical exemplary embodiments of the invention have been disclosed, and although specific terms are employed, they are used in a generic and descriptive sense only, and not for the purposes of limitation, the scope of the invention being as set forth in the following claims.