WO2017056504A1

WO2017056504A1 - Seat slide apparatus for vehicle and method for manufacturing the same

Info

Publication number: WO2017056504A1
Application number: PCT/JP2016/004422
Authority: WO
Inventors: Daisuke Iguchi; Hirotsugu Kuroda
Original assignee: Fuji Kiko Co., Ltd.
Priority date: 2015-10-02
Filing date: 2016-09-30
Publication date: 2017-04-06

Abstract

A seat slide apparatus for vehicle, comprising a lower rail and an upper rail supported engaged with the lower rail in a slidably movable manner.　The lower rail is provided with a stopper-contacting section at at least one longitudinal end of its downward flange portion.　The upper rail is provided with a stopper piece at its longitudinal center part, the stopper piece being formed bent integrally with the upper rail in a manner to lie astride an upper rail's side wall portion and an upward flange portion of the upper rail.　The position of at least one slide stroke end of slide stroke of the upper rail with respect to the lower rail is restricted by the stopper-contacting section and the stopper piece being brought into contact with each other.

Description

SEAT SLIDE APPARATUS FOR VEHICLE AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a seat slide apparatus for vehicle and a method for manufacturing the same, and more particularly to: a seat slide apparatus having a structure where a stopper can regulate the position of the end of slide stroke of an upper rail with respect to a lower rail in adjusting the position of a seat; and a method for manufacturing the same.

In this kind of seat slide apparatus, either one of an upper rail (serving as "a movable side rail") and a lower rail (serving as "a fixed side rail") is provided to have a stopper section at its longitudinal center part while the other one is similarly provided with two stopper sections respectively at longitudinal front and rear locations, in order to regulate the position of the end of slide stroke of the upper rail with respect to the lower rail.　When the stopper sections of both of the rails are brought into contact with each other, the position of the end of forward/backward slide stroke of the upper rail with respect to the lower rail is regulated.

For example, for the purpose of improving the strength of the stopper section of the movable side upper rail on the prediction that the seat slide apparatus has such a stopper structure, there is proposed in Patent Document 1 a seat slide apparatus wherein a stopper member (or a locking member) is provided inserted between a side wall portion of the upper rail and a folded-back wall portion formed integral therewith, in the state of being supported by both of them.

[Patent Literature 1]　Japanese Patent Application Publication No. 2013-001328

However, in the structure discussed in Patent Document 1, since a stopper member obtained by folding a metal plate material to have the shape of the letter U is press fitted between the side wall portion and the folded-back wall portion of the upper rail so as to be bridged therebetween in the state of being supported by both of them, the number of parts is increased to complicate the structure.　In addition, not only the number of parts but also the number of man-hours for boring and assembling is increased thereby bringing about a problem of a cost increase.

The present invention has been made in view of the above-described problems, the object of which is to provide a seat reclining apparatus for vehicle which does not bring about the increase of the number of parts and man-hours for assembling while improving the strength of the upper rail-side stopper section in particular.

A first aspect of the present invention resides in a seat slide apparatus for vehicle, comprising: a lower rail fixed to a floor part of a vehicle body; and an upper rail supported engaged with the lower rail in a slidably movable manner so that the position of a seat secured to the upper rail is adjustable in the longitudinal direction of the lower rail.

In the first aspect, the lower rail comprises: a bottom wall portion; a lower rail's side wall portions disposed at both sides of the bottom wall portion; and a downward flange portion formed bent inwardly from a top end portion of the lower rail's side wall portion, thereby having a shape opening upwardly.　Additionally, the upper rail comprises: a top wall portion; an upper rail's side wall portion disposed at both sides of the top wall portion; and an upward flange portion formed bent outwardly from a bottom end portion of the upper rail's side wall portion to intervene between the lower rail's side wall portion and the downward flange portion of the lower rail, thereby having a shape opening downwardly.

In addition, the lower rail further has a stopper-contacting section at at least one longitudinal end of the downward flange portion, and the upper rail further has a stopper piece at the bottom end portion of its longitudinal center part, the stopper piece being formed bent integrally with the upper rail in a manner to lie astride both the upper rail's side wall portion and the upward flange portion of the upper rail.　The position of at least one of both slide stroke ends of slide stroke of the upper rail with respect to the lower rail is restricted by the stopper-contacting section and the stopper piece being brought into contact with each other.

In this arrangement, the upper rail includes a section lying astride the upper rail's side wall portion and the upward flange portion, and the stopper piece is formed by partially cutting and upwardly raising the section.

More specifically, the stopper piece is formed bent laterally from the upper rail's side wall portion toward the upward flange portion in a manner to continue from the upper rail's side wall portion while being separated from the upward flange portion at its tip end section, and the stopper piece is engaged at the separated tip end section with an engagement groove formed on the side of the upward flange portion, thereby being supported by both the upper rail's side wall portion and the upward flange portion.

Alternatively, the stopper piece is formed bent laterally from the upward flange portion toward the upper rail's side wall portion in a manner to continue from the upward flange portion while being separated from the upper rail's side wall portion at its tip end section, and the stopper piece is engaged at the separated tip end section with an engagement groove formed on the side of the upper rail's side wall portion, thereby being supported by both the upward flange portion and the upper rail's side wall portion.

The stopper piece may be formed by partially upwardly concaving the section lying astride the upper rail's side wall portion and the upward flange portion.

More specifically, the upper rail is formed with a plurality of slot-like through holes at the bottom end portion of the longitudinal center part and at the section lying astride the upper rail's side wall portion and the upward flange portion, and the stopper piece is formed by upwardly concaving a region interposed between two adjacent ones of the slot-like through holes.

Moreover, the upper rail is provided with a lock mechanism for controlling a locked/unlocked state of the upper rail with respect to the lower rail, the upper rail's side wall portion of the upper rail is formed to have at the longitudinal center part an engagement hole with which a locking claw member of the lock mechanism is engageable, and the stopper piece is formed adjacent to the engagement hole at at least one side of the longitudinal direction of the upper rail.　Such an arrangement is preferable in view of forming the engagement hole and the stopper piece concurrently.

A second aspect of the present invention resides in a method for manufacturing a seat slide apparatus for vehicle comprising: a lower rail fixed to a floor part of a vehicle body; and an upper rail supported engaged with the lower rail in a slidably movable manner.　The method comprises the steps of: (i) shaping an upper rail into the final form, the upper rail comprising: a top wall portion; an upper rail's side wall portion disposed at both sides of the top wall portion; and an upward flange portion formed bent outwardly from a bottom end portion of the upper rail's side wall portion, the upper rail being formed defining a plurality of slot-like through holes at the bottom end portion of a longitudinal center part of the upper rail and at a section lying astride the upper rail's side wall portion and the upward flange portion, and (ii) upwardly concaving a region of the upper rail interposed between two adjacent ones of the slot-like through holes, in the middle of forming the upward flange portion of the upper rail by bending, thereby producing a stopper piece which can restrict the position of at least one of both slide stroke ends of slide stroke of the upper rail with respect to the lower rail when the upper rail is supported engaged with the lower rail and when the stopper piece is brought into contact with a stopper-contacting section provided to the lower rail, and then forming the upward flange portion of the upper rail by bending into the final form after completing the stopper piece.

According to the present invention, the stopper piece provided to the upper rail side is formed bent integrally with the upper rail in a manner to lie astride both the upper rail's side wall portion and the upward flange portion of the upper rail, and therefore substantially supported by both the upper rail's side wall portion and the upward flange portion.　With this, not only the stopper piece can be improved in strength, but also it is possible to so reduce the number of parts and the number of man-hours as to result in a cost reduction since there is no necessity to attach an independent foreign member as the stopper piece.

Additionally, the engagement hole and the stopper piece, which are provided to the upper rail side in relation to the lock mechanism, are disposed adjacent to each other.　With this, processes for forming these components (for example, slitting process etc.) become able to be performed substantially concurrently.　Hence the number of man-hours can be more reduced and therefore it is possible to expect a further cost reduction.

Furthermore, since the stopper piece can concurrently be produced within a series of processes for shaping the upper rail into the final form, the productivity for the upper rail can be improved.

Fig. 1 is a perspective view of an example of a seat to which a seat slide apparatus for vehicle according to the present invention is applied. Fig. 2 is an exploded perspective view of a first embodiment of a seat slide apparatus for vehicle according to the present invention, schematically illustrating the structure of a seat slide apparatus adopted in the seat as shown in Fig. 1. Fig. 3 is a side view of the seat slide apparatus as shown in Fig. 2 but showing the state of having been assembled. Fig. 4 is a plan view of the seat slide apparatus as shown in Fig. 3 in the state of having been assembled. Fig. 5 is an enlarged cross-sectional view taken along the line A-A of Fig. 3. Fig. 6 is an enlarged cross-sectional view taken along the line B-B of Fig. 3. Fig. 7 is a cross-sectional view of a lower rail alone as shown in Figs. 3 and 4, taken along the longitudinal direction of the lower rail. Fig. 8 is a plan view of an upper rail alone as shown in Figs. 3 and 4. Fig. 9 is a side view of the upper rail as shown in Fig. 8. Fig. 10 is an enlarged perspective view of the upper rail as shown in Fig. 9, taken from diagonally below. Fig. 11 is an enlarged cross-sectional view similar to Fig. 5 but showing a second embodiment of a seat slide apparatus for vehicle according to the present invention. Fig. 12 is a cross-sectional view of the seat slide apparatus for vehicle as shown in Fig. 11 in the state of having been assembled. Fig. 13 is an enlarged cross-sectional view similar to Fig. 5 but showing a third embodiment of a seat slide apparatus for vehicle according to the present invention. Fig. 14 is a cross-sectional view similar to Fig. 7 but showing a fourth embodiment of a seat slide apparatus for vehicle according to the present invention. Fig. 15 is an enlarged cross-sectional view of a part corresponding to that taken along the line C-C of Fig. 3, but showing a fifth embodiment of a seat slide apparatus for vehicle according to the present invention. Fig. 16 is a plan view of an upper rail alone as shown in Fig. 15. Fig. 17 is a side view of the upper rail alone as shown in Fig. 15. Fig. 18 is an enlarged perspective view of the upper rail as shown in Fig. 15, taken from diagonally below. Fig. 19 is an illustration of the flow of steps for press-forming the upper rail, particularly involving steps before and after press-forming a stopper piece.

Figs. 1 to 10 illustrate a first embodiment of a seat slide apparatus for vehicle according to the present invention.　Particularly, Fig. 1 is a perspective view of an example of a vehicle seat 1 and Fig. 2 is an exploded perspective view schematically illustrating the structure of a seat slide apparatus 5 employed in the seat 1 as shown in Fig. 1.　Additionally, Figs. 3 and 4 show a side view and a plan view of the seat slide apparatus 5 in the state of having been assembled, respectively.　Furthermore, Figs. 5 and 6 are enlarged cross-sectional views taken along the lines A-A and B-B of Fig. 3, respectively.

As shown in Fig. 1, a vehicle seat 1 is provided to include a seat cushion 2 serving as a seat face, and a seat back 3 behaving as a backrest part as well known.　The seat back 3 is adjustable in its forward/backward inclination with respect to the seat cushion 2, through a reclining mechanism 4.　The seat cushion 2 is supported at its bottom surface by a seat frame, and the seat frame is secured to an upper rail of the seat slide apparatus 5 (though not shown).

The seat slide apparatus 5 as shown in Fig. 1 is provided to have a left and right pair of assembled rails 5a as shown in Figs. 2 to 4, in which the pair of assembled rails 5a being so disposed that their longitudinal directions are parallel to a back-and-forth direction of a vehicle.　As illustrated in Figs. 2 to 4, each one of the assembled rails 5a is comprised of: a lower rail 6 formed of metal and fixed to a floor surface (or a floor part) of a vehicle body; an upper rail 7 similarly formed of metal and fixed to the seat frame disposed below the seat cushion 2 as shown in Fig. 1; a guide member 8 for reducing the frictional resistance caused when the upper rail 7 is slidably moved with respect to the lower rail 6 on the occasion of adjusting the position of the seat 1 in the back-and-forth direction; and a lock mechanism 9 which controls a locked/unlocked state where the upper rail 7 can be held at a position arbitrary in its longitudinal direction with respect to the lower rail 6.　The upper rail 7 is supported engaged with the lower rail 6 in a slidably movable manner.　In other words, the position of the seat 1 fixed to the upper rail 7 is adjustable along the longitudinal direction of the lower rail 6.　The pair of assembled rails 5a are in association with each other through an operation lever 10 of the lock mechanism 9 as will be mentioned later, which results in a sharing of the operation lever 10 between the pair of assembled rails 5a.　Incidentally, an illustration of the operation lever 10 is omitted in Figs. 3 and 4.

Fig. 7 is a cross-sectional view of a lower rail alone as shown in Figs. 2 to 4, taken along the longitudinal direction of the lower rail.　As shown not only in Figs. 5 and 6 but also in Fig. 7, the lower rail 6 is constituted of: a bottom wall portion 6a fixed to the floor surface of the vehicle body; a pair of side wall portions 6b upwardly extending from the both sides of the bottom wall portion 6a; intermediate wall portions 6c folded inwardly at the top ends (or the upper ends) of the side wall portions 6b; and downward flange portions 6d folded further inwardly through the intermediate wall portions 6c to extend downwardly.　As a whole, the lower rail 6 is so formed as to open at its upper section and generally has a modified U shape in cross section.　A space defined between the side wall portion 6b and the downward flange portion 6d oppositely facing to each other behaves as a space for housing the upper rail 7 as will be discussed below, together with a space defined between the oppositely-facing pair of downward

flange portions

6d, 6d.

The pair of downward flange portions 6d of the lower rail 6 each is provided to include:

ordinary parts

11a, 11b at back-and-forth both end parts in the longitudinal direction, respectively; and lock teeth part 11c at a center part except for the

ordinary parts

11a, 11b, the lock teeth part 11c having the so-called sawtooth shape where projection parts and depression parts are alternatively formed along the longitudinal direction.　The lock teeth part 11c is engageably attachable to locking claws 16c of the lock mechanism 9 as will be mentioned below, with which the lock teeth part 11c is allowed to control the locked/unlocked state of the upper rail 7 with respect to the lower rail 6 in cooperation with the lock mechanism 9.

Each of the

ordinary parts

11a, 11b disposed at the front and rear ends of the downward flange portion 6d of the lower rail 6 is formed extending more downwardly than the lock teeth part 11c around a boundary part between itself and the lock teeth part 11c.　Additionally the boundary part between each of the front and rear

ordinary parts

11a, 11b and the lock teeth part 11c is formed with a step-like part 11d serving as a section to be brought into contact with a stopper.　Incidentally, the lower rail 6 has a symmetrical shape in cross section taken perpendicularly to its longitudinal direction, and the positions of lock teeth parts 11c of the pair of downward flange portions 6d are in agreement with each other in the longitudinal direction.　Likewise, the positions of front and rear step-like parts 11d in the longitudinal direction are coincident between the pair of downward flange portions 6d.

Figs. 8 and 9 are a plan view and a side view of the upper rail 7, respectively.　In addition, Fig. 10 is an enlarged perspective view of an essential part, taken from an oblique direction upon reversing the upper rail 7 as shown in Fig. 9.

As shown in Figs. 5, 6, 8 and 9, the upper rail 7 is constituted of: a top wall portion 7a fixed to the seat frame of the above-mentioned seat cushion 2; a pair of side wall portions 7b downwardly extending from the both sides of the top wall portion 7a; and upward flange portions 7c folded outwardly and upwardly at the bottom ends (or the lower ends) of the side wall portions 7b.　As a whole, the upper rail 7 is so formed as to open at its lower section and generally has a modified U shape in cross section.

The pair of upward flange portions 7c of the upper rail 7 is formed continuously extending in the longitudinal direction but shaped differently between its longitudinal center part and the other part as shown in Figs. 8 and 9.　While the longitudinal center part of the upward flange portion 7c is formed to have at its upper half a vertical wall part 17a parallel to the side wall portion 7b, the other part is formed as a bending flange part 17b having a lower-half inclined portion 27a and an upper-half inclined portion 27b thereby exhibiting a bent shape in cross section as shown in Fig. 6.

More specifically, the pair of upward flange portions 7c of the upper rail 7 is shaped such that its lower-half inclined portion 27a located close to the side wall portion 7b or located on the root side is formed commonly throughout the longitudinal length of the upward flange portion 7c as shown in Figs. 5 and 6 while at the longitudinal center part the vertical wall part 17a is formed instead of the upper-half inclined portion 27b to extend upwardly from the top end of the lower-half inclined portion 27a to be parallel with the side wall portion 7b as shown in Fig. 5.　On the other hand, the bending flange part 17b serving as the other part than the longitudinal center part of the pair of upward flange portions 7c of the upper rail 7 is formed having the lower-half inclined portion 27a and the upper-half inclined portion 27b thereby exhibiting a bent shape in cross section where the upward flange portion 7c itself projects outwardly at the midsection of the height of the flange, and additionally formed having at the tip end of the upper-half inclined portion 27b an end flange portion extending parallel with the side wall portion 7b, as shown in Fig. 6.　With such an arrangement, there is created a step at a longitudinal interface between an upper end portion of the vertical wall part 17a and that of the bending flange part 17b as shown in Fig. 8; more specifically, the vertical wall part 17a and the upper-half inclined portion 27b of the bending flange part 17b (including the end flange portion 27c) are formed continued toward each other in the longitudinal direction through an inclined connect part 17c intervening therebetween.　Incidentally, the lower-half inclined portion 27a has a slightly inwardly recessed shape as shown in Fig. 6.

As shown in Figs. 2 and 6, the guide member 8 is to be installed between the upper and lower curved portions of the lower rail 6 and the bending flange part 17b of the upper rail 7 as will be discussed later, and therefore the outer surface of the lower-half inclined portion 27a and the outer surface extending through the upper-half inclined portion and the end flange portion 27c of the bending flange part are to also function as a raceway surface for a

ball

15a or 15b (a rolling element of the undermentioned guide member 8).

When the upper rail 7 is attached to the lower rail 6, each of the upward flange portions 7c that the upper rail 7 has at its both sides is to be disposed in a manner to intervene between the side wall portion 6b and the downward flange portion 6d as shown in Figs. 5 and 6, regardless of the vertical wall part 17a or the bending flange part 17b.

As shown in Figs. 2, 8 and 9, the upper rail 7 is formed to have, at its longitudinal center part, vertically extending three long slot-like engagement holes 13 and a pair of stopper pieces 14 disposed at both sides of the engagement holes 13, which are arranged in a line.　These two stopper pieces 14 are provided in a manner to lie astride both the side wall portion 7b of the upper rail 7 and the vertical wall part 17a serving as a part of the upward flange portion 7c, and cut and raised upwardly as shown in Fig. 5; in other words, the stopper pieces 14 are supported by both the side wall portion 7b and the vertical wall part 17a in a manner to lie astride the side wall portion 7b and the vertical wall part 17a.

More specifically, the stopper pieces 14 are punch-shaped by press machining into bridges disposed at both sides of the three aligned engagement holes 13 (but the bridges are cut at their one end) in a manner to define a pair of auxiliary holes 13a at their both sides, and more concretely, provided by die-cutting to remain together with a pair of bridge sections 13b as shown in Fig. 10.　Namely, two of the three aligned engagement holes 13, defined at both end, are to also behave as the auxiliary holes 13a.　At the time of punching, the pair of stopper pieces 14 have a posture cut and raised upwardly as compared with a state as shown in Fig. 10.　Moreover, the pair of stopper pieces 14 are formed integrally continuously from the side wall portions 7b and folded laterally toward the upward flange portions 7c and cut and raised upwardly, but not integral with the upward flange portions 7c as apparent from Fig. 5.　This is because the perimeter that the stopper piece 14 needs is shorter than that of the bridge section 13b adjacent thereto.

By performing an after-processing, the stopper piece 14 obtains a normal shape as shown in Figs. 5 and 10 where the stopper piece 14 is smooth and folded to be perpendicular to the side wall portion 7b.　The stopper piece 14 having the normal shape is engaged with an engagement groove 14b at a tip end section 14a, the engagement groove 14b being formed such that a separating gap defined connecting the two auxiliary holes 13a is partially cut away.　With such a structure that the stopper pieces 14 are cut to independently remain between the two auxiliary holes 13a, the engagement holes 13 are formed not only between the

bridge sections

13b, 13b but also between one stopper piece 14 and one bridge section 13b adjacent thereto.　As a result of the presence of a pair of bridge sections 13b and a pair of stopper pieces 14, three engagement holes 13 in total are to be formed at a certain interval.

Additionally, each of the stopper pieces 14 is engaged at the tip end section 14a with the engagement groove 14b formed at an upper end section of the lower-half inclined portion 27a of the upward flange portion 7c, so as to be able to cope with an external force acting thereon from the longitudinal direction of the upper rail 7, in the state of being supported by both the side wall portion 7b and the upward flange portion 7c.　Incidentally, the pair of bridge sections 13b are located at the same pitch as that of teeth of the lock teeth part 11c so as to be engageable between adjacent claws of three locking claws 16c.　The end-side engagement holes 13 disposed at both sides of the pair of bridge sections 13b are so defined as to spread toward the stopper piece 14 thereby being greater than the center engagement hole 13 in width.　In a normal status, the end-side engagement holes 13 are arranged to define a slight gap between its stopper piece 14-side imaginary plane and the locking claw 16c.　With this, a dimensional change caused by bending the stopper piece 14 does not exert an influence upon the engagement of the locking claw 16.

The stopper piece 14 is provided with such a dimension as to be engaged with either one of the step-like parts 11d of the lower rail 6 only when inserting a ball (as the guide member 8) between the upper rail 7 and the lower rail 6 after attaching the upper rail 7 to the specified position, and not to be engaged with the step-like parts 11d of the lower rail 6 when attaching the upper rail 7 to the lower rail 6 (incidentally, the stopper piece 14 does not interfere with the step-like parts 11d of the lower rail 6 by bringing the upper rail 7 into contact with the bottom wall portion 6a of the lower rail 6 at the time of attaching the upper rail 7 to the lower rail 6 as shown in Fig. 5 or by inserting the upper rail 7 into the lower rail 6 while bringing the upper rail 7 close to the bottom wall portion 6a if not bringing the upper rail 7 into contact with the bottom wall portion 6a).

Furthermore, the upper rail 7 has a symmetrical shape in cross section taken perpendicularly to its longitudinal direction, similarly to the lower rail 6.　Hence the pair of stopper pieces 14 lying astride the side wall portion 7b and the upward flange portion 7c of the upper rail 7, and the three engagement holes 13 are provided symmetrically as apparent from Figs. 5 and 10.

As shown in Fig. 7, the sliding motion of the upper rail 7 with respect to the lower rail 6 toward the front direction (the leftward direction of Fig. 7), and more specifically, the position of the slide stroke end of the upper rail 7 is restricted by the vehicle-front-side stopper piece 14 of the upper rail 7 being brought into contact with the vehicle-front-side step-like part 11d of the lower rail 6.　Likewise, the sliding motion of the upper rail 7 with respect to the lower rail 6 toward the rear direction (the rightward direction of Fig. 7), and more specifically, the position of the slide stroke end of the upper rail 7 is restricted by the vehicle-rear-side stopper piece 14 of the upper rail 7 being brought into contact with the vehicle-rear-side step-like part 11d of the lower rail 6.

The guide member 8 as shown in Fig. 2 has the function of the so-called linear bearing, and constituted of four

balls

15a, 15b (formed of steel) and a metallic retainer 15c for rollably supporting the four

balls

15a, 15b (a rolling element of the undermentioned guide member 8 as also shown in Fig. 6.　In this first embodiment, two balls 15a disposed at the lower side of Fig. 6 are larger than the other two balls 15b disposed at the upper side of Fig. 6 in diameter.　The lower side balls 15a each is located interposed between a lower-side curved portion of the lower rail 6 (a curved portion formed between the bottom wall portion 6a and the side wall portion 6b) and the lower-half inclined portion 27a of the bending flange part 17b of the upper rail 7, while the upper side balls 15b each is located interposed between a upper-side curved portion of the lower rail 6 (a curved portion formed between the side wall portion 6b and the intermediate wall portion 6c) the upper-half inclined portion 27b of the bending flange part 17b of the upper rail 7.

As shown in Figs. 2 and 3, the guide member 8 is placed on two positions opposing to each other in the wide direction of the

rails

6, 7 and on front and rear two positions in the longitudinal direction of the

rails

6, 7, and accordingly placed on four positions in total.　Additionally, concerning the side of the lower rail 6, the slidably movable range of a front-side guide member 8 is restricted by first front and first rear raised

sections

20a, 20b provided raised inward the lower rail 6, and similarly, the slidably movable range of a rear-side guide member 8 is restricted by second front and second rear raised

sections

21a, 21b provided raised inward the lower rail 6 as shown in Fig. 3.　Moreover, the upper rail 7 is formed further with a plurality of

projections

22a, 22b, 23a and 23b at the lower-half inclined portion 27a of the upward flange portion 7c as shown in Figs. 9 and 10.　With this structure, on the side of the upper rail 7, the slidably movable range of a front-side guide member 8 is restricted by first front and first

rear projections

22a, 22b, and similarly, the slidably movable range of a rear-side guide member 8 is restricted by second front and second

rear projections

23a, 23b as shown in Fig. 3.

The lock mechanism 9 as shown in Fig. 2 is to function by utilizing the lock teeth part 11c (see Fig. 7) formed in the pair of downward flange portions 6d of the lower rail 6, and to be secured to the top wall portion 7a of the upper rail 7 at its one end as shown in Figs. 2 and 3.　At the other end of lock mechanism 9 there are provided: a slim locking member 16 slidably movable in the vertical direction within a space defined between the opposingly facing pair of the

side wall portions

7b, 7b of the upper rail 7; a metallic operation lever 10 for performing a swing operation of the locking member 16; and a lever spring 18 for holding the operation lever 10 with its biasing force.

The locking member 16 is constructed from a slim metal plate formed of a spring material and folded into a step-like shape, for example.　The locking member 16 is fastened to the top wall portion 7a of the upper rail 7 not only through a through hole 16a formed at one end of the locking member 16 but also through an attachment hole formed in the top wall portion 7a of the upper rail 7, with a pin member 19.　Furthermore, the locking member 16 is bent at a part near the through hole 16a to be formed with a step 16b as shown in Fig. 2.　As will be discussed below, when performing a locking/unlocking operation, the locking member 16 is to be elastically deformed by its own elastic force around the vicinity of the step 16b (serving as a deformation fulcrum), thereby producing its swing motions.

The locking member 16 is further formed with a plurality of locking claws 16c at the other end, at which the locking member 16 is engageable with the lock teeth part 11c of the lower rail 6.　These locking claws 16c are also engageable with the engagement holes 13 formed in the pair of side wall portions 7b of the upper rail 7.　Namely, by the other end of the lock member 16 swinging, both engagement and disengagement (or release) of a plurality of locking claws 16c from the lock teeth part 11c and the pair of bridge sections 13b are concurrently become feasible.

The operation lever 10 as shown in Fig. 2 is provided to include: a grip section 10a extending along the width direction of the seat 1; rail-inserting sections 10b extending in the longitudinal direction of the

rails

6, 7 from both end of the grip section 10a; and an intermediate connect sections 10c formed b bent to connect the grip section 10a and each of the rail-inserting sections 10b with step difference.　As a whole, the operation lever 10 is formed to have a U-like shape in planar view.　For example, a processed rodlike pipe may be used as the operation lever 10.

The pair of rail-inserting sections 10b of the operation lever 10 are respectively inserted into the upper rails 7 of the independently assembled left and right rails 5a, and subjected to positioning in the longitudinal direction.　In addition, an end portion of the rail-inserting section 10b goes through the downside of the lock member 16 and inserted into an insertion hole 16d of the lock member 16 from below upward; more specifically, the rail-inserting section 10b substantially pierces the lock member 16, and the end portion thereof reaches above a part formed with a plurality of locking claws 16c.　The operation lever 10 is thus connected to the lock member 16.　Furthermore, since the assembled rails 5a as shown in Fig. 2 are disposed left and right independently as mentioned above, the operation lever 10 is shared between the left and right pair of the assembled rails 5a.

A lever spring 18 as shown in Fig. 2 is the so-called wire form spring obtained by laterally symmetrically folding a metal spring wire material, where one end of the lever spring 18 is formed as a connecting portion 18a while the other end is bent to serve as a projecting portion 18b.　By engaging the projecting portion 18b with a spring-attached hole 18d formed in the side wall portion 7b of the upper rail 7 (see Fig. 4), the lever spring 18 is fixedly supported by the upper rail 7 and concurrently the connecting portion 18a of the lever spring 18 is engaged with the bottom surface of the rail-inserting section 10b to be inserted in such a manner as to straddle the lever spring 18 as shown in Fig. 3.　With this, a biasing force which biases the grip section 10a upwardly is to always act on the operation lever 10 as shown in Fig. 2.　Incidentally, since this biasing force of the lever spring 18 is smaller than that of the locking member 16, the lock member 16 never be released from the locked state by the biasing force of the lever spring 18.

Given that in the lock mechanism 9 the upper rail 7 is located at any position within its slide stroke with respect to the lower rail 6 as shown in Fig. 3 (in reality, Fig. 3 does not illustrate the operation lever 10 but illustrates a state where the upper rail 7 is located at its rearmost stroke end with respect to the lower rail 6), the operation lever 10 is to receive from the lever spring 18 an upward biasing force swingable about the lower surface of the head of the pin member 19 of the locking member 16 as shown in Fig. 2, so that the operation lever 10 is in unloaded state or a state where no operation force acts thereon.　In the following description, this state will be referred to as the initial position.

A condition where the operation lever 10 is located at the initial position means that the locking member 16 is biased swingably upwardly about the vicinity of the step 16b of the locking member 16 or that the lock mechanism 9 is in the locked state.　In the locked state, a plurality of locking claws 16c of the locking member 16 are engaged concurrently with the lock teeth part 11c of the lower rail 6 and a plurality of engagement holes 13 of the upper rail 7.　With this, the slidable movement of the upper rail 7 (more specifically, the slidable movement of the seat 1 fixed to the upper rail 7) with respect to the lower rail 6 is inhibited so that the locked state is maintained by itself.

On the other hand, when holding the grip section 10a of the operation lever 10 and pulling it upward from the initial position, the operation lever 10 is moved swingably about the lower surface of the head of the pin member 19 and then the end portion of the rail-inserting section 10b pushes a rear end section of the locking member 16 down; namely, the operation lever 10 and the locking member 16 are substantially swingably moved together with each other.　Then, a plurality of locking claws 16c are disengaged from the lock teeth part 11c of the lower rail 6 and from a plurality of engagement holes 13 of the upper rail 7 concurrently.　In other words, by pulling the grip section 10a of the operation lever 10 upward from the initial position, a unlocked state (or a released state) where the upper rail 7 (more specifically, the seat 1 fixed to the upper rail 7) becomes slidably movable along the lower rail 6 is established.

By releasing the operation lever 10 from the operation force while maintaining the unlocked state upon adjusting the position of the seat 1 in its front/rear direction, the locked state comes back again.

In the first embodiment of the seat slide apparatus 5 having the above-mentioned lock mechanism 9, if moving the upper rail 7 to the position of the rearmost stroke end (i.e. a position at which the slide toward the rear direction of the vehicle is limited) with respect to the lower rail 6 while keeping the unlocked state, there can be obtained a state as shown in Figs. 3 and 4.　In this state, as shown in not only Figs. 3 and 4 but also Fig. 7, the rear-side stopper piece 14 of the upper rail 7 is to be brought into contact with the rear-side step-like part 11d of the lower rail 6.　With this, the position of the rearmost slide stroke end (i.e. the rearmost position of the slide stroke) within the slide stroke range of the upper rail 7 with respect to the lower rail 6 is restricted and therefore a further backward slidable movement of the upper rail 7 with respect to the lower rail 6 is inhibited.　More specifically, the rear-side step-like part 11d of the lower rail 6 and the rear-side stopper piece 14 of the upper rail 7 restrict the position of the rearmost slide stroke end with respect to the lower rail 6 within the slide stroke range of the upper rail 7, by being brought into contact with each other.

On the contrary if moving the upper rail 7 to the position of the forwardmost stroke end (i.e. a position at which the slide toward the forward direction of the vehicle is limited) with respect to the lower rail 6, the front-side stopper piece 14 of the upper rail 7 is to be brought into contact with the front-side step-like part 11d of the lower rail 6 as shown in Figs. 3 and 7.　With this, the position of the forwardmost slide stroke end (i.e. the rearmost position of the slide stroke) within the slide stroke range of the upper rail 7 with respect to the lower rail 6 is restricted and therefore a further forward slidable movement of the upper rail 7 with respect to the lower rail 6 is inhibited.　More specifically, the front-side step-like part 11d of the lower rail 6 and the front-side stopper piece 14 of the upper rail 7 restrict the position of the forwardmost slide stroke end with respect to the lower rail 6 within the slide stroke range of the upper rail 7, by being brought into contact with each other.

Thus, at the time of slidably moving the upper rail 7 to the position of the forwardmost or rearmost slide stroke end with respect to the lower rail 6, an end surface of either one of the front-side and rear-side stopper pieces 14 of the upper rail 7 is brought into contact with an end surface of either one of the front-side and rear side step-like parts 11d of the lower rail 6 as shown in Figs. 3, 5 and 7, in a manner to make the shape of a cross when viewed from the longitudinal direction.　In either case, the stopper piece 14 exhibits great rigidity on the occasion of being brought into contact with the step-like part 11d since the stopper piece 14 is supported by both the side wall portion 7b and the upward flange portion 7c of the upper rail 7 as shown in Figs. 5 and 10 so as to improve in strength.

Additionally, the stopper piece 14 is integrally formed in such a manner as to be cut and raised at its section lying astride the side wall portion 7b and the upward flange portion 7c of the upper rail 7, so that it is not necessary to attach an independent member as the stopper piece 14.　Since the number of parts and the number of man-hours are thus reduced, it is also possible to expect a cost reduction.　In addition, a plurality of engagement holes 13 and the stopper pieces 14 of the upper rail 7, which relate to the lock mechanism 9, are arranged adjacent to each other; therefore, processes for forming them (including slitting process, for example) can substantially simultaneously be carried out, with which also the number of man-hours can be reduced and it becomes possible to expect a further cost reduction.

The stopper piece 14 and the step-like part 11d, which are to restrict the slidable movement of the upper rail 7 with respect to the lower rail 6, have previously been formed before attaching the upper rail 7 to the lower rail 6 as mentioned above.　Hence on the occasion of attaching the upper rail 7 to the lower rail 6, the upper rail 7 is firstly inserted up to the specified position from the front end side or rear end side of the lower rail 6 while maintaining a state of being brought into contact with the bottom wall portion 6a of the lower rail 6 or a state of being brought close to the bottom wall portion 6a if not brought into contact therewith (i.e. a state of being able to prevent the interference between the stopper piece 14 and the step-like part 11d), and thereafter attached to the lower rail 6 by being moved horizontally upwardly.　Since it is not necessary to conduct a process for forming the stopper piece 14 and the step-like part 11d under a state where the upper rail 7 has been attached to the lower rail 6, the ability of the upper rail 7 to be attached to the lower rail 6 can be improved.　Moreover, it is not necessary to apply an external force for after-processing, so that the lower rail 6 and the upper rail 7 may be improved in stabilizing their respective cross-sectional shape under the assembled state.

However, there is sometimes a possibility that the interference between the stopper piece 14 and the step-like part 11d cannot be avoided according to the difference of the specification of the seat slide apparatus 5 and the like even if bringing the upper rail 7 into contact with the bottom wall portion 6a of the lower rail 6 as shown in Fig. 5 when attaching the upper rail 7 to the lower rail 6.　In these cases, the stopper piece 14 is previously imperfectly bent to such an extent as to be able to avoid the interference between the stopper piece 14 and the step-like part 11d.　Then, and more specifically after completing the attachment of upper rail 7 to the lower rail 6, the stopper piece 14 is subjected to a further bending until bent up to the normal position as shown in Fig. 10.

Figs. 11 and 12 show a second embodiment of the seat slide apparatus 5 according to the present invention, in which parts in common with Fig. 5 are given the same reference numerals.

In the second embodiment, a stopper piece 24 has a raised shape like the stopper piece as shown in Fig. 5, but formed integrally continuously from the upward flange portions 7c (or the vertical wall part 17a) and folded laterally toward the side wall portions 7b, as apparent from a comparison between Fig. 11 and Fig. 5.　Additionally, the stopper piece 24 is once cut away from the side wall portion 7b at its tip end section 24a and engaged at the tip end section 24a with a groove serving as a part of the auxiliary hole 13a defined around the stopper piece 24, similarly to Figs. 5 and 10.

The second embodiment is no different from the first one in that the stopper piece 24 is supported by both the side wall portion 7b and the upward flange portion 7c of the upper rail 7, and therefore the same effects as in the first embodiment can be obtained.

On the occasion of attaching the upper rail 7 to the lower rail 6 in the second embodiment, the upper rail 7 is firstly inserted up to the specified position from the front end side or rear end side of the lower rail 6 while maintaining a state of being brought into contact with the bottom wall portion 6a of the lower rail 6 or a state of being brought close to the bottom wall portion 6a if not brought into contact therewith (i.e. a state of being able to prevent the interference between the stopper piece 14 and the step-like part 11d), and thereafter attached to the lower rail 6 by being moved horizontally upwardly.

However, there is sometimes a possibility that the interference between the stopper piece 14 and the step-like part 11d of the lower rail 6 cannot be avoided according to the difference of the specification of the seat slide apparatus 5 and the like even if bringing the upper rail 7 into contact with the bottom wall portion 6a of the lower rail 6 as shown in Fig. 11 when attaching the upper rail 7 to the lower rail 6, as mentioned above.　In these cases, the stopper piece 14 is previously imperfectly bent to such an extent as to be able to avoid the interference between the stopper piece 14 and the step-like part 11d as shown in Fig. 12.　Then, and more specifically after completing the attachment of upper rail 7 to the lower rail 6, the stopper piece 24 is subjected to a further bending until bent up to the normal position as shown in Fig. 11.

Fig. 13 shows a third embodiment of the seat slide apparatus 5 according to the present invention, in which parts in common with Fig. 5 are given the same reference numerals.

In the third embodiment, either one of a group consisting of the front-side pair of step-like parts 11d and the front-side pair of stopper pieces 14 and a group consisting of the rear-side pair of step-like parts 11d and the rear-side pair of stopper pieces 14 as shown in Fig. 7 is kept employed and the other one is abolished.　In compensation therefor, a rising section 25a is provided as a stopper-contacting section to the bottom wall portion 6a of the lower rail 6 while a stopper piece 25b relating to the rising section 25a is formed projecting downwardly from the side wall portion 7b of the upper rail 7 as shown in Fig. 13.

With this, it becomes possible to insert the upper rail 7 into the lower rail 6 from the side where the step-like part 11d is abolished, and therefore the necessity to accomplish the attachment so as not to cause the interference between the stopper piece 14 and the step-like part 11d disappears, so that the ability of the upper rail 7 to be attached to the lower rail 6 can be improved.

The third embodiment is also no different from the first embodiment in that the stopper piece 14 is supported by both the side wall portion 7b and the upward flange portion 7c of the upper rail 7, and therefore the same effects (e.g. the strength-enhancing effect etc.) as in the first embodiment can be obtained.

Incidentally, the present invention is also applicable to a seat slide apparatus employing a lock mechanism where the upper rail 7 is fixed to an arbitrary position of the lower rail 6 through a mechanism different from the lock mechanism 9 of the above-mentioned first embodiment.

For instance, in the case of the seat slide apparatus 5 having a lock mechanism where the locking claws of the locking member engaged with the lower rail 6 and the upper rail 7 are rotated about the longitudinal axis of the upper rail 7 when operating the operation lever 10 at the grip section 10a, the lock teeth part 11c formed in the downward flange portion 6d of the lower rail 6 (see Fig. 7) and the downwardly opening engagement holes 13 of the upper rail 7 may be replaced with lock holes 28 formed mutually independently and aligned along the longitudinal direction as shown in Fig. 14 (a forth embodiment).　The objects of the present invention are attained in this case also, as well as the above-mentioned embodiments.

Figs. 15 to 19 illustrate a fifth embodiment of the seat slide apparatus 5 according to the present invention, in which parts in common with Figs. 5, 6 and 8-10 are given the same reference numerals.

In the fifth embodiment, a stopper piece 31 is not of a cut-and-raised type but formed to be partially concaved in the upward direction (or toward the top wall portion 7a of the upper rail 7) at its section lying astride the side wall portion 7b and the upward flange portion 7c of the upper rail 7 as shown in Fig. 15.　Incidentally, Fig. 15 is a cross-sectional view of a part corresponding to the vehicle-front-side inclined connect part 17c intervening between the vertical wall part 17a and the upper-half inclined portion 27b, e.g., a cross-sectional view of a part corresponding to that taken along the line C-C of Fig. 3.

As shown in Figs. 16 to 18, the upper rail 7 is formed to have, at its longitudinal center part, three engagement holes 13 and three auxiliary holes 13a arranged in a line.　At both sides of the three engagement holes 13, the auxiliary holes 13a are formed.　More concretely, one auxiliary hole 13a is formed on the vehicle-front side of the three engagement holes 13 while two other auxiliary holes 13a are formed on the vehicle-rear side of the three engagement holes 13.　The engagement holes 13 and the auxiliary holes 13a of the fifth embodiment are defined astride the side wall portion 7b and the upward flange portion 7c of the upper rail 7.

A rectangular portion interposed between an auxiliary hole 13a serving as a vehicle-front-side through hole and an engagement hole 13 serving as a through hole adjacent to the vehicle-front-side auxiliary hole 13a is deformed to concave in the upward direction (or toward the top wall portion 7a of the upper rail 7) thereby behaving as the stopper piece 31.

Accordingly, the stopper piece 31 is supported by both the side wall portion 7b and the upward flange portion 7c of the upper rail 7 in a manner to lie astride the side wall portion 7b and the upward flange portion 7c as shown in Fig. 15.

Furthermore, the stopper piece 31 is formed generally parallel with the top wall portion 7a of the upper rail 7 and generally perpendicular to the side wall portion 7b.　The location of an upward flange portion 7c-side end section of the stopper piece 31 corresponds to the vicinity of the location of the upper end of the lower-half inclined portion 27a of the bending flange part 17b, in the vertical direction.　In other words, the engagement hole 13 and the auxiliary hole 13a formed adjacent to the both sides of the stopper piece 31 is provided such that their respective one end is positioned at the vicinity of the location of the lower end of the upper-half inclined portion 27b of the bending flange part 17b.

The stopper piece 31 can restrict the position of the forwardmost slide stroke end of the slide movement of the upper rail 7 with respect to the lower rail 6, by being brought into contact with the front-side step-like part 11d of the lower rail 6.

The stopper piece 31 is provided with such a dimension as to be engaged with the step-like part 11d of the lower rail 6 only when inserting a ball (as the guide member 8) between the upper rail 7 and the lower rail 6 after attaching the upper rail 7 to the specified position, and not to be engaged with the step-like part 11d of the lower rail 6 when attaching the upper rail 7 to the lower rail 6 (incidentally, the stopper piece 31 does not interfere with the step-like part 11d of the lower rail 6 by bringing the upper rail 7 into contact with the bottom wall portion 6a of the lower rail 6 at the time of attaching the upper rail 7 to the lower rail 6 as shown in Fig. 15 or by inserting the upper rail 7 into the lower rail 6 while bringing the upper rail 7 close to the bottom wall portion 6a of the lower rail 6 if not bringing the upper rail 7 into contact with the bottom wall portion 6a).

Another rectangular portion interposed between the two vehicle-rear-side auxiliary holes 13a is provided separated at the upward flange portion 7c-side end section and serves as a vertical stopper piece 32 formed linearly continuously from the side wall portion 7b of the upper rail 7.　The vertical stopper piece 32 corresponds to the stopper piece 25b of the above-mentioned third embodiment.

The vertical stopper piece 32 can restrict the position of the rearmost slide stroke end of the slide movement of the upper rail 7 with respect to the lower rail 6, by being brought into contact with a component corresponding to the rising section 25a provided to the lower rail 6 of the third embodiment.

The fifth embodiment is also no different from the first embodiment in that the stopper piece 31 is supported by both the side wall portion 7b and the upward flange portion 7c of the upper rail 7, and therefore the same effects as in the first embodiment can be obtained.

The stopper piece 31 is formed connected at its one end to the side wall portion 7b of the upper rail 7 while being formed connected at the other end to the upward flange portion 7c of the upper rail 7.　Namely, both of the ends of the stopper piece 31 are formed integral with the upper rail 7, which contributes to the improvement of the relative strength of the stopper piece 31.

Additionally, the stopper piece 31 is formed in the process of press-forming the upper rail 7.　More specifically, at the time of processing the upper rail 7 through a series of transfer press processes and the like starting from a plate material and ending with the final form, the stopper piece 31 is simultaneously press-formed to have a desired normal shape (a desired final form).　In other words, the stopper piece 31 is not formed after completing the upper rail 7 but formed concurrently with the processes on each part of the upper rail 7.

To be more specific, the rectangular portion interposed between the front-side auxiliary hole 13a and the engagement hole 13 adjacent to the front-side auxiliary hole 13a is subjected to pressing immediately before a step of folding the upper rail 7 up to the position at which the upward flange portion 7c reaches have the normal shape (the final form), thereby obtaining the normal shape of stopper piece 31.

Fig. 19 is an illustration showing the flow of the steps for press-forming the upper rail 7, particularly involving steps before and after press-forming the stopper piece 31.

The upper rail 7 in a process A of Fig. 19 shows a state where the so-called blank material is sequentially subjected to press-bending.　In the process A, the upward flange portion 7c is generally formed by folding but not yet formed into the normal shape.

The upper rail 7 in the process A is then subjected to press forming by using upper and lower dies 33, 34 for use in stopper piece-molding, thereby obtaining the stopper piece 31 (see a process B of Fig. 19).

The upper rail 7 completing the formation of the stopper piece 31 is thereafter disposed between upper and lower dies 35, 36 for use in final shaping of the upper flange portion, and then folded up to the normal position of the upward flange portion 7c (see a process C of Fig. 19).

The upper rail 7 in which the stopper piece 31 has already been formed gets pushed at the upward flange portion 7c by a tapered surface 35a of the upper die 35 as the upper die 35 descends from above.　The upper die 35 is descended to a position determined in consideration of springback (which may occur after press forming) thereby folding the upward flange portion 7c until the upward flange portion 7c attains its normal shape (see a process D of Fig. 19).　With this, a series of press-forming processes for the upper rail 7 terminates.

Since the press forming of the stopper piece 31 can concurrently be accomplished within a series of press-forming processes for forming the upper rail 7 into the final form, it becomes unnecessary to conduct an after-processing for forming the stopper piece 31 into the normal shape.　Hence the productivity for the upper rail 7 can be improved.

Incidentally, in the above-mentioned fifth embodiment of the seat slide apparatus, the vertical stopper piece 32 may be removed and the stopper piece 31 may be formed at both sides of the three aligned engagement holes 13.　In this case, a relatively front-side one of the vehicle-rear-side pair of auxiliary holes 13a, adjacent to the engagement hole 13 is abolished.

"The vertical direction" referred to in this specification means a vertical direction in the state where the seat slide apparatus 5 is fixed to the floor, and therefore it can also be said to be a direction perpendicular to the floor or a vehicle height direction.　It corresponds to the vertical direction of Fig. 5.　Meanwhile, "the front/rear direction" referred to in this specification means a back-and-forth direction of a vehicle on which the seat slide apparatus is mounted, and corresponds to a direction perpendicular to the sheet of Fig. 5 and a vertical direction of Fig. 7.

The entire contents of Japanese Patent Application No. 2016-057799 filed March 23, 2016 are herein incorporated by reference.　Although the invention has been described above by reference to certain embodiments and examples of the invention, the invention is not limited to the embodiments and examples described above.　Modifications and variations of the embodiments and examples described above will occur to those skilled in the art, in light of the above teachings.　The scope of the invention is defined with reference to the following claims.

Claims

　A seat slide apparatus for vehicle, comprising:
　a lower rail fixed to a floor part of a vehicle body; and
　an upper rail supported engaged with the lower rail in a slidably movable manner so that the position of a seat secured to the upper rail is adjustable in the longitudinal direction of the lower rail,
　wherein
　the lower rail comprises: a bottom wall portion; a lower rail's side wall portions disposed at both sides of the bottom wall portion; and a downward flange portion formed bent inwardly from a top end portion of the lower rail's side wall portion, thereby having a shape opening upwardly,
　the upper rail comprises: a top wall portion; an upper rail's side wall portion disposed at both sides of the top wall portion; and an upward flange portion formed bent outwardly from a bottom end portion of the upper rail's side wall portion to intervene between the lower rail's side wall portion and the downward flange portion of the lower rail, thereby having a shape opening downwardly,
　the lower rail further has a stopper-contacting section at at least one longitudinal end of the downward flange portion,
　the upper rail further has a stopper piece at the bottom end portion of its longitudinal center part, the stopper piece being formed bent integrally with the upper rail in a manner to lie astride both the upper rail's side wall portion and the upward flange portion of the upper rail, and
　the position of at least one of both slide stroke ends of slide stroke of the upper rail with respect to the lower rail is restricted by the stopper-contacting section and the stopper piece being brought into contact with each other.
　A seat slide apparatus for vehicle, as claimed in claim 1, wherein the upper rail includes a section lying astride the upper rail's side wall portion and the upward flange portion, and the stopper piece is formed by partially cutting and upwardly raising the section.
　A seat slide apparatus for vehicle, as claimed in claim 2, wherein the stopper piece is formed bent laterally from the upper rail's side wall portion toward the upward flange portion in a manner to continue from the upper rail's side wall portion while being separated from the upward flange portion at its tip end section, and the stopper piece is engaged at the separated tip end section with an engagement groove formed on the side of the upward flange portion, thereby being supported by both the upper rail's side wall portion and the upward flange portion.
　A seat slide apparatus for vehicle, as claimed in claim 2, wherein the stopper piece is formed bent laterally from the upward flange portion toward the upper rail's side wall portion in a manner to continue from the upward flange portion while being separated from the upper rail's side wall portion at its tip end section, and the stopper piece is engaged at the separated tip end section with an engagement groove formed on the side of the upper rail's side wall portion, thereby being supported by both the upward flange portion and the upper rail's side wall portion.
　A seat slide apparatus for vehicle, as claimed in claim 1, wherein the upper rail includes a section lying astride the upper rail's side wall portion and the upward flange portion, and the stopper piece is formed by partially upwardly concaving the section.
　A seat slide apparatus for vehicle, as claimed in claim 5, wherein the upper rail is formed with a plurality of slot-like through holes at the bottom end portion of the longitudinal center part and at the section lying astride the upper rail's side wall portion and the upward flange portion, and the stopper piece is formed by upwardly concaving a region interposed between two adjacent ones of the slot-like through holes.
　A seat slide apparatus for vehicle, as claimed in any one of claims 1 to 6, wherein the upper rail is provided with a lock mechanism for controlling a locked/unlocked state of the upper rail with respect to the lower rail, the upper rail's side wall portion of the upper rail is formed to have at the longitudinal center part an engagement hole with which a locking claw member of the lock mechanism is engageable, and the stopper piece is formed adjacent to the engagement hole at at least one side of the longitudinal direction of the upper rail.
　A method for manufacturing a seat slide apparatus for vehicle comprising: a lower rail fixed to a floor part of a vehicle body; and an upper rail supported engaged with the lower rail in a slidably movable manner, comprising the steps of:
　shaping an upper rail into the final form, the upper rail comprising: a top wall portion; an upper rail's side wall portion disposed at both sides of the top wall portion; and an upward flange portion formed bent outwardly from a bottom end portion of the upper rail's side wall portion, the upper rail being formed defining a plurality of slot-like through holes at the bottom end portion of a longitudinal center part of the upper rail and at a section lying astride the upper rail's side wall portion and the upward flange portion, and
　upwardly concaving a region of the upper rail interposed between two adjacent ones of the slot-like through holes, in the middle of forming the upward flange portion of the upper rail by bending, thereby producing a stopper piece which can restrict the position of at least one of both slide stroke ends of slide stroke of the upper rail with respect to the lower rail when the upper rail is supported engaged with the lower rail and when the stopper piece is brought into contact with a stopper-contacting section provided to the lower rail, and then forming the upward flange portion of the upper rail by bending into the final form after completing the stopper piece.