Patent Description:
A seat sliding device includes: a lower rail attached to the floor of a vehicle; an upper rail slidably provided on the lower rail and connected to a seat frame; and a pair of left and right seat slide adjusters each having a locking mechanism for fixing the front and rear sliding positions of the upper rail. The locking mechanisms each include: a lock plate having engagement holes or the like which engage with teeth formed in the lower rail; a locking spring member which biases the lock plate in an engagement direction; and a release lever which is linked to the lock plate to operate the lock plate in a disengagement direction against the elastic force of the locking spring member. The seat sliding device further includes a slide lever connecting the release levers of the pair of left and right seat slide adjusters and operated by a person.

A conventional method often employed to connect a slide lever to a release lever is rivet caulking, but a specialized tool is required for caulking the rivet, or a backlash may occur at a fastened part. Further, when a lock plate is locked to teeth of a lower rail, a slight impact occurs, and because of the impact, the fastened part, if having the backlash, may slightly rattle to generate abnormal noise. As a solution to this, <CIT> has proposed an art to connect them with a tubular spring having inwardly raised pieces and outwardly raised pieces therebetween.

Another seat sliding device is disclosed in <CIT> forming the basis for the preamble of claim <NUM>. Similar seat sliding devices are known from <CIT> and <CIT>. <CIT>discloses a seat sliding device in which an engagement member is assembled on an upper rail, a second rotary shaft portion is inserted to a shaft receiving bore of a first side wall portion from an inner side of an upper rail. After the insertion, the engagement member is rotated so that the second rotary shaft portion is inserted to the shaft receiving bore of the second side wall portion. Because a shaft allowable length is specified to be greater than a shaft maximum rotation length, an interruption of an insertion of the rotary shaft portion because of a contact of the second rotary shaft portion with an edge portion of the shaft receiving bore at the second side wall portion is restrained. In the seat sliding device of <CIT>, the lower rail is provided with a stopper-contacting section at one longitudinal end of a downward flange portion. The upper rail is provided with a stopper piece at its longitudinal center part, the stopper piece being 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 one slide stroke end 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 further seat sliding device is disclosed in <CIT> including a lower rail, an upper rail, a lock mechanism, a spring member and an unlocking handle. The lock mechanism is provided within the upper rail and restricts the movement of the upper rail relative to the lower rail. The spring member is provided within the upper rail. The unlocking handle is operated against the pressing force of the spring member to remove restrictions on the movement of the upper rail imposed by the lock mechanism.

The art of <CIT> is advantageous in that the slide lever is easily attached to the release lever and the elasticity of the tubular spring reduces the rattling of the connection part. However, in the state of being interposed between the slide lever and the release lever, the tubular spring is integrated with the inner surface of the slide lever and the elasticity of a tubular main body of the tubular spring does not act much, and the elasticity of the inwardly raised pieces and the outwardly raised pieces protruding from the tubular main body mainly acts. That is, the elasticity corresponding to the protrusion length of these raised pieces from the tubular main body acts, but because of the short protrusion length, a spring constant is high, and there is still room for improvement in the effect of reducing the rattling between the slide lever and the release lever.

The present invention was made in consideration of the above and has an object to provide a seat sliding device whose slide lever and release lever can be easily connected and that has less rattling therebetween and generates less abnormal noise.

To solve the aforesaid problem, a seat sliding device of the present invention includes:.

Preferably, the front lock part has a substantially rectangular shape whose sides include the bent end and whose side opposite the bent end is the acting end, and is more apart from the two wire parts as the front lock part goes from the bent end toward the acting end.

According to the present invention, the connecting end part of the slide lever has a tubular shape and the front end part of the release lever is inserted in the connecting end part with the connection spring member therebetween. The connection spring member is formed of a worked wire for springs and has the bent end located forward and the wire parts extending rearward from the bent end. The protruding engagement parts are formed in the wire parts. In the state in which the wire parts are placed inside the front end part of the release lever with the protruding engagement parts protruding from the engagement protrusion holes of the release lever in advance, the tubular connecting end part of the slide lever is fitted on the outer side of the release lever. The connection can be easily done by the protruding engagement parts of the connection spring member engaging with the engagement holes of the slide lever. Further, the protruding engagement parts engage with both the engagement protrusion holes of the release lever and the engagement holes of the slide lever, and the front lock part including the bent end located forward is locked with its acting end pressing the inner surface of the connecting end part of the slide lever. This enables the easy and sure connection of the slide lever and the release lever.

Further, the entire connection spring member is formed of the wire material for springs, and the wire parts between the protruding engagement parts and the front lock part are not fixed to the inner surface of the slide lever. Therefore, elasticity corresponding to the length from the protruding engagement parts to the bent end is exhibited. If the wire parts between the protruding engagement parts and the front lock part are fixed to some place, the spring constant becomes high because actually functioning elasticity corresponds to that of a spring shorter than the length of the wire parts, but in the connecting structure of the present invention, this does not occur, and the elasticity of the connection spring member functions with the spring constant corresponding to the length of the wire parts between the protruding engagement parts and the front lock part. This makes it possible not only to easily and surely connect the slide lever and the release lever with less rattling therebetween but also to absorb even a slight impact occurring at the locking operation time of the lock plate, achieving a higher effect of reducing the generation of abnormal noise.

The present invention will be hereinafter described in more detail based on an embodiment illustrated in the drawings. As illustrated in <FIG>, a seat frame S is provided such that its forward and rearward sliding can be adjusted by a pair of left and right seat sliding devices <NUM> of this embodiment that are a predetermined interval apart from each other in the width direction of the vehicle body. A slide lever <NUM> extending between left and right seat slide adjusters <NUM>, <NUM> included in the seat sliding device <NUM> is provided below a front edge of a seat cushion frame S1. The slide lever <NUM> connects later-described release levers <NUM>, <NUM> of locking mechanisms <NUM>, <NUM> provided in the left and right seat slide adjusters <NUM>, <NUM>, and the locking is released when the slide lever <NUM> is operated by a person.

In the following, with reference to mainly <FIG> which illustrate only one of the seat slide adjusters <NUM>, <NUM>, its detailed structure will be described, but the left and right seat slide adjusters <NUM>, <NUM> illustrated in <FIG> and <FIG> have the same structure.

The seat slide adjuster <NUM> included in the seat sliding device <NUM> of this embodiment includes a lower rail <NUM> and an upper rail <NUM> slidable in the longitudinal direction of the lower rail <NUM>. The lower rail <NUM> is fixed to the vehicle body floor and the upper rail <NUM> is connected to a side frame S11 of the seat cushion frame S1 of the seat frame S.

The lower rail <NUM> has a bottom wall 11a, a pair of vertical walls 11b, 11b rising from both sides of the bottom wall 11a to face each other, a pair of upper walls 11c, 11c which are bent inward from upper edges of the vertical walls 11b, 11b and whose facing edges are a predetermined distance apart from each other, and inner walls 11d, 11d bent downward from inner edges of the upper walls 11c, 11c. The lower rail <NUM> has a substantially C-shape with its upper surface being open in the widthwise cross section orthogonal to the longitudinal direction (see <FIG> and <FIG>).

The upper rail <NUM> has an upper wall 12a and a pair of sidewalls 12b, 12b bent downward from both sides of the upper wall 12a to face each other, and has a substantially C-shaped widthwise cross section with its lower surface being open. The upper rail <NUM> further has: bottom walls 12c, 12c with a predetermined width bent outward in a substantially horizontal direction from lower ends of the sidewalls 12b, 12b; and vertical walls 12d, 12d bent upward from outer edges of the bottom walls 12c, 12c (see <FIG>). The vertical walls 12d, 12d of the upper rail <NUM> are located between the vertical walls 11b, 11b and the inner walls 11d, 11d of the lower rail <NUM> to face the vertical walls 11b, 11b of the lower rail <NUM>.

Between the lower rail <NUM> and the upper rail <NUM>, sliding resistance reducing members <NUM>, <NUM> are provided as illustrated in <FIG> and <FIG>. Preferably, the plurality of sliding resistance reducing members <NUM>, <NUM> are arranged at a predetermined interval in the longitudinal direction of the lower rail <NUM>, and in this embodiment, the sliding resistance reducing members <NUM>, <NUM> are provided in the vicinity of the front and the rear of the lower rail <NUM> respectively.

The sliding resistance reducing members <NUM>, <NUM> disposed in the vicinity of the front (hereinafter, referred to as "front sliding resistance reducing members") substantially face each other across the widthwise middle of the lower rail <NUM> and they are provided in pair so as to correspond respectively to the left and right vertical walls 11b, 11b of the lower rail <NUM>. Specifically, the front sliding resistance reducing members <NUM>, <NUM> include retainers (front retainers) <NUM>, <NUM> having a substantially L-shaped widthwise cross section and having a several cm length along the longitudinal direction of the lower rail <NUM>. The front retainers <NUM>, <NUM> having the substantially L-shaped cross section include first retaining walls <NUM>, <NUM> extending in the vertical direction and second retaining walls <NUM>, <NUM> extending in the lateral direction from lower ends of the first retaining walls <NUM>, <NUM> toward the widthwise middle of the lower rail <NUM>. Preferably, the front sliding resistance reducing members <NUM>, <NUM> are formed of synthetic resin and have flexibility so that the first retaining walls <NUM>, <NUM> are bendable relative to the second retaining walls <NUM>, <NUM>.

The front retainers <NUM>, <NUM> are disposed with the first retaining walls <NUM>, <NUM> located between the vertical walls 11b, 11b of the lower rail <NUM> and the vertical walls 12d, 12d of the upper rail <NUM> and with the second retaining walls <NUM>, <NUM> located between the bottom wall 11a of the lower rail <NUM> and the bottom walls 12c, 12c of the upper rail <NUM>.

The first retaining walls <NUM>, <NUM> each have one or more ball member retaining parts 1411a, 1411a, and in this embodiment, they each have the ball member retaining parts 1411a, 1411a at two places along the longitudinal direction of the lower rail <NUM>. In the ball member retaining parts 1411a, 1411a, first ball members <NUM>, <NUM> are rotatably disposed.

The second retaining walls <NUM>, <NUM> each also have one or more ball member retaining parts 1412a, 1412a. In this embodiment, the ball member retaining parts 1412a, 1412a are formed at two places along the longitudinal direction of the lower rail <NUM>. In the ball member retaining parts 1412a, 1412a of the second retaining walls <NUM>, <NUM>, second ball members <NUM>, <NUM> are rotatably disposed.

The sliding resistance reducing members <NUM>, <NUM> disposed in the vicinity of the rear (hereinafter, "rear sliding resistance reducing members") also substantially face each other across the widthwise middle of the lower rail <NUM> and they are provided in pair to correspond respectively to the left and right vertical walls 11b, 11b of the lower rail <NUM>, similarly to the front sliding resistance reducing members <NUM>, <NUM> as illustrated in <FIG>. The rear sliding resistance reducing members <NUM>, <NUM>, which have substantially the same structure as that of the front sliding resistance reducing members <NUM>, <NUM>, include retainers (rear retainers) <NUM>, <NUM> having a substantially L-shaped widthwise cross section and having the same length as that of the front retainers <NUM>, <NUM> along the longitudinal direction of the lower rail <NUM>. The retainers <NUM>, <NUM> include first retaining walls <NUM>, <NUM> extending in the vertical direction and second retaining walls <NUM>, <NUM> extending in the lateral direction from lower ends of the first retaining walls <NUM>, <NUM> toward the widthwise middle Z of the lower rail <NUM>. It is also preferable that the rear sliding resistance reducing members <NUM>, <NUM> are formed of synthetic resin and have flexibility so that the first retaining walls <NUM>, <NUM> are bendable relative to the second retaining walls <NUM>, <NUM>.

The rear retainers <NUM>, <NUM> are also disposed with the first retaining walls <NUM>, <NUM> located between the vertical walls 11b, 11b of the lower rail <NUM> and the vertical walls 12d, 12d of the upper rail <NUM> and with the second retaining walls <NUM>, <NUM> located between the bottom wall 11a of the lower rail <NUM> and the bottom walls 12c, 12c of the upper rail <NUM>.

The first retaining walls <NUM>, <NUM> of the rear retainers <NUM>, <NUM> each have one or more ball member retaining parts 1511a, 1511a, and in this embodiment, they each have the ball member retaining parts 1511a, 1511a at two places along the longitudinal direction of the lower rail <NUM>. In the ball member retaining parts 1511a, 1511a, first ball members <NUM>, <NUM> are rotatably disposed in contact with the vertical walls 11b, 11b of the lower rail <NUM> and the vertical walls 12d, 12d of the upper rail <NUM>. Further, the second retaining walls <NUM>, <NUM> each also have one or more ball member retaining parts 1512a, 1512a.

Note that the number of the ball member retaining parts 1512a, 1512a of the second retaining walls <NUM>, <NUM> of the rear retainers <NUM>, <NUM> is three in this embodiment as illustrated in <FIG>. Specifically, the two ball member retaining parts 1512a, 1512a are arranged along the longitudinal direction of the lower rail <NUM> at positions a predetermined distance apart from the vertical walls 11b, 11b of the lower rail <NUM> toward the widthwise middle Z of the lower rail <NUM>, and the one is formed still closer to the widthwise middle of the lower rail <NUM>. Accordingly, the second retaining walls <NUM>, <NUM> of the rear retainers <NUM>, <NUM> are substantially triangular in a plan view and their apexes are directed toward the widthwise middle of the lower rail <NUM>.

Further, the second ball members <NUM>, <NUM> are disposed in the three ball member retaining parts 1512a, 1512a formed in each of the second retaining walls <NUM>, <NUM>, and the total number of the second ball members <NUM>, <NUM> in each of the second retaining walls <NUM>, <NUM> is three. A load applied to the seat slide adjuster <NUM> is larger in its rearward part than in its forward part by about <NUM> to <NUM>%. Therefore, the number of the second ball members <NUM>, <NUM> disposed in the second retaining walls <NUM>, <NUM> of the rear retainers <NUM>, <NUM> is preferably larger than the number of the second ball members <NUM>, <NUM> disposed in the front retainers <NUM>, <NUM>.

The seat slide adjuster <NUM> of this embodiment has the aforesaid sliding resistance reducing members <NUM>, <NUM>. The front retainers <NUM>, <NUM> and the rear retainers <NUM>, <NUM> both have the substantially L-shaped cross section and have the first retaining walls <NUM>, <NUM>, <NUM>, <NUM> in which the first ball members <NUM>, <NUM>, <NUM>, <NUM> are disposed and the second retaining walls <NUM>, <NUM>, <NUM>, <NUM> in which the second ball members <NUM>, <NUM>, <NUM>, <NUM> are disposed. The second retaining walls <NUM>, <NUM>, <NUM>, <NUM> are disposed between the bottom wall 11a of the lower rail <NUM> and the bottom walls 12c, 12c of the upper rail <NUM>, and the first retaining walls <NUM>, <NUM>, <NUM>, <NUM> are disposed between the vertical walls 11b, 11b of the lower rail <NUM> and the vertical walls 12d, 12d of the upper rail <NUM>. In addition, the first ball members <NUM>, <NUM>, <NUM>, <NUM> are supported at positions apart from both the upper walls 11c 11c and the bottom wall 11a of the lower rail <NUM> within a range of the vertical walls 11b, 11b of the lower rail <NUM>, and the second ball members <NUM>, <NUM>, <NUM>, <NUM> are supported at positions apart from the vertical walls 11b, 11b of the lower rail <NUM> toward the widthwise middle Z. That is, the first ball members <NUM>, <NUM>, <NUM>, <NUM> are disposed not at positions where rigidity is high such as the corner parts between the vertical walls 11b, 11b and the upper walls 11c, 11c of the lower rail <NUM> and the corner parts between the vertical walls 11b, 11b and the bottom wall 11a of the lower rail <NUM> but at positions therebetween where rigidity is low. Further, the second ball members <NUM>, <NUM>, <NUM>, <NUM> connect with the first ball members <NUM>, <NUM>, <NUM>, <NUM> through the retainers <NUM>, <NUM>, <NUM>, <NUM> having a substantially L-shaped cross section.

Accordingly, when a load is applied from any of the up and down directions and the lateral directions by the weight, a posture change, or the like of the person to try to deform the vertical walls 11b, 11b of the lower rail <NUM> and the vertical walls 12d, 12d of the upper rail <NUM> outward or in the opposite direction, the front retainers <NUM>, <NUM> and the rear retainers <NUM>, <NUM> which both have a substantially L-shaped cross sectiont is configured such that the second retaining walls <NUM>, <NUM>, <NUM>, <NUM> bend relative to the first retaining walls <NUM>, <NUM>, <NUM>, <NUM> with the first ball members <NUM>, <NUM>, <NUM>, <NUM> being fulcrums, and thus have high followability to the deformation of the lower rail <NUM> and the upper rail <NUM>. Consequently, as the lower rail <NUM> and the upper rail <NUM> bend, the first ball members <NUM>, <NUM>, <NUM>, <NUM> and the second ball members <NUM>, <NUM>, <NUM>, <NUM> change in their positions to keep in contact with the lower rail <NUM> and the upper rail <NUM>. As a result, rattling is reduced, abnormal noise is also reduced, and slidability of the upper rail <NUM> on the lower rail <NUM> is less reduced.

As described above, the sliding resistance reducing members <NUM>, <NUM> of this embodiment have high followability to the deformation of the lower rail <NUM> and the upper rail <NUM> caused by a load, and have high effects of reducing rattling, reducing abnormal noise, and making slidability less reduced, and accordingly, there is a larger tolerance for the deformation of the lower rail <NUM> and the upper rail <NUM> than conventionally. This allows the material of the lower rail <NUM> and the upper rail <NUM> to be thinner even if the same material is used, to contribute to a weight reduction of the seat slide adjuster <NUM>.

In <FIG> and <FIG>, reference sign <NUM> denotes the locking mechanism. This locking mechanism <NUM> includes the release lever <NUM> and a lock plate <NUM>. The release lever <NUM> has a predetermined length and is disposed on the inner side of the lower rail <NUM> and the upper rail <NUM>. The release lever <NUM> has a front end part 161a projecting from a front end of the upper rail <NUM>, and the aforesaid slide lever <NUM> operated by a person is connected to the front end part 161a. In the release lever <NUM>, when the front end part 161a is displaced up or down on the longitudinal-direction middle, its rear end part 161b is displaced in the opposite direction. The lower rail <NUM> includes mating engagement parts 11e (in this embodiment, constituted by a plurality of projecting pieces in a comb-teeth shape provided in the inner walls 11d, 11d), and in the configuration that the lock plate <NUM> including an engagement part 162b (in this embodiment, constituted by holes in which the projecting pieces are inserted) engageable with the mating engagement part 11e is linked to the rear end part, lifting up the slide lever <NUM> to displace the front end part 161a of the release lever <NUM> in the upward direction causes the engagement part 162b of the lock plate <NUM> to come off the mating engagement part 11e to produce an unlocked state, allowing the forward/rearward sliding movement. The displacement of the release lever <NUM> in the opposite direction causes the engagement part 162b to engage with the mating engagement part 11e to produce a locked state, and this opposite-direction movement is caused by the elastic force of a leaf spring member <NUM>, as a locking spring member, biasing the release lever <NUM> in the engagement direction.

To enable such an operation of the release lever <NUM>, it is pivotally supported at its longitudinal-direction middle by the upper rail <NUM>. Specifically, the release lever <NUM> has, in its longitudinal-direction middle, a protrusion 161c engageable with a hole 12a1 formed in the upper wall 12a of the upper rail <NUM>. Further, the leaf spring member <NUM> is disposed between an upper surface 161d of the release lever <NUM> and the upper wall 12a of the upper rail <NUM> to cover the protrusion 161c. The leaf spring member <NUM> has a base part 163a covering the protrusion 161c and disposed in the hole 12a1 together with the protrusion 161c. The leaf spring <NUM> further has two acting pieces 163b, 163c extending rearward from the base part 163a. The two acting pieces 163b, 163c are inserted into the release lever <NUM> through a through-hole <NUM> formed at the back of the protrusion 161c of the release lever <NUM>. Consequently, the spring force of the leaf spring member <NUM> acts in such a direction as to displace the acting pieces 163b, 163c upward with respect to the base part 163a disposed in the hole 12a1. The acting piece 163b is engaged with an engagement hole 161f formed in the rear end part 161b of the release lever <NUM>, and the other acting piece 163c is engaged with a connection hole 162d formed in a plate part 162a of the lock plate <NUM>. Consequently, the rear end part 161b of the release lever <NUM> and the lock plate <NUM> are constantly biased upward, and the engagement part 162b of the lock plate <NUM> is constantly biased in such a direction as to engage with the mating engagement part 11e of the lower frame <NUM>.

Therefore, when an operator displaces the slide lever <NUM> upward, the front end part 161a of the release lever <NUM> connected to the slide lever <NUM> is displaced upward and the engagement part 162b comes off the mating engagement part 11e against the elastic force of the leaf spring member <NUM>. On the other hand, when the operator takes his/her hand off the slide lever <NUM>, the engagement part 162b engages with the mating engagement part 11e owing to the elastic force of the leaf spring member <NUM>, resulting in the locking.

The lock plate <NUM> has a shaft part 162c at one end in terms of the width direction (the same direction as the width direction of the lower rail <NUM> and the upper rail <NUM>) and at the other end, has the substantially rectangular plate part 162a having the aforesaid engagement part 162b. In the vertical walls 12d of the upper rail <NUM> and the sidewalls 12b adjacent thereto, insertion holes 12e to which the plate part 162a is insertable are formed (note that the insertion hole 12e is formed on each side, but <FIG> illustrates only that on one side, and the similar insertion hole 12e is formed on the side where the lock plate <NUM> is illustrated). The lock plate <NUM> is inserted into the insertion holes 12e with the engagement part 162b being a leading end, and is disposed with the shaft part 162c supported by a bearing part provided in the vertical wall 12d. Consequently, the plate part 162a of the lock plate <NUM> pivots up and down on the shaft part 162c, and the engagement part 162b constituted by the holes engages/disengages with/from the mating engagement part 11e of the lower frame <NUM>.

Next, the slide lever <NUM> used in this embodiment will be described. As illustrated in <FIG> and <FIG>, the slide lever <NUM> has: an operation part <NUM> provided below the front edge of the seat cushion frame S1 and extending in the lateral direction between the pair of left and right seat slide adjusters <NUM>, <NUM> included in the seat sliding device <NUM>; and connecting end parts <NUM>, <NUM> bent downward at a substantially right angle near ends of the operation part <NUM>, further bent rearward at a substantially right angle, and extending in the longitudinal direction of the lower rail <NUM> and the upper rail <NUM>. The connecting end parts <NUM>, <NUM> have a closed ring-shaped cross section. Through the connecting end parts <NUM>, <NUM>, the front end parts 161a of the release levers <NUM> are connected.

In this embodiment, the release lever <NUM> and the slide lever <NUM> are connected with a connection spring member <NUM> therebetween. The connection spring member <NUM> is formed of a wire material for springs such as a piano wire or a hard-drawn steel wire worked into a predetermined shape. Specifically, as illustrated in <FIG> and <FIG>, the connection spring member <NUM> has two wire parts <NUM>, <NUM> formed of one wire material bent near the middle, and on a bent end 181a side of the two wire parts <NUM>, <NUM>, a front lock part <NUM> including the bent end 181a as its one side and worked into a substantially rectangular shape in a plan view is formed. The front lock part <NUM> obliquely rises in such a direction as to be more apart from the two wire parts <NUM>, <NUM> as it goes toward an acting end 182a which is a side opposite to the bent end 181a. Further, on rear end parts 181b, 181b sides of the two wire parts <NUM>, <NUM>, protruding engagement parts <NUM>, <NUM> are formed whose middle portions bulge outward in a substantially C-shape in a plan view. The protruding engagement parts <NUM>, <NUM> have the substantially C-shape, but more correctly, they are shaped to have oblique sides 183a, 183a that become more outward as they go rearward along the longitudinal direction and also have rear sides 183b, 183b that meet with the rear ends of the oblique sides 183a, 183a and lines along the two wire parts <NUM>, <NUM> at a substantially right angle. Consequently, when the acting end 182a of the front lock part <NUM> is pressed in such a direction as to approach the wire parts <NUM>, <NUM>, restoring force acts in such a direction as to cause the acting end 182a to separate from the wire parts <NUM>, <NUM>, and when the two wire parts <NUM>, <NUM> are made to approach each other, restoring force acts in such a direction as to cause them to separate from each other.

The vicinity of the front end part 161a of the release lever <NUM> has a substantially semi-tubular shape, and in its side surface at a position apart from an open end 161a1 of the front end part 161a by a predetermined length along the longitudinal direction (the length L1 indicated in <FIG> (length substantially corresponding to the distance L2 from the bent end 181a of the connection spring member <NUM> to the position where the rear sides 183b, 183b of the protruding engagement parts <NUM>, <NUM> are formed)), engagement protrusion holes 161e, 161e are formed. Since the oblique sides 183a, 183a of the protruding engagement parts <NUM>, <NUM> have a predetermined length in the longitudinal direction, the engagement protrusion holes 161e, 161e have a long hole shape with a length corresponding to the aforesaid predetermined length.

The connecting end parts <NUM>, <NUM> of the slide lever <NUM> each have, in a side surface, engagement holes 172b, 172b at a rearward position apart from an open end 172a by a predetermined length (the length L4 in <FIG>). The front end part 161a of the release lever <NUM> is inserted into the connecting end part <NUM>, and at this time, the open end 172a of the connecting end part <NUM> abuts on a stopper 161f which is protrudingly formed on the side surface of the release lever <NUM> at a position apart rearward from the engagement protrusion holes 161e, 161e by a predetermined length along the longitudinal direction (the length L3 in <FIG> (corresponding to the length L4)). Accordingly, the engagement protrusion holes 161e, 161e and the engagement holes 172b, 172b are aligned with each other when the front end part 161a is inserted until the open end 172a of the connecting end part <NUM> abuts on the stopper 161f.

As described above, to connect the slide lever <NUM> and the release lever <NUM>, the two wire parts <NUM>, <NUM> of the connection spring member <NUM> are first inserted into the semi-tubular front end part 161a of the release lever <NUM> with the rear end parts 181b, 181b being leading sides. At the time of this insertion, the two wire parts <NUM>, <NUM> are made to approach each other. Consequently, when the protruding engagement parts <NUM>, <NUM> reach the position of the engagement protrusion holes 161e, 161e of the release lever <NUM>, the wire parts <NUM>, <NUM> move away from each other owing to their restoring force to protrude outward from the engagement protrusion holes 161e, 161e. As a result, the bent end 181a of the connection spring member <NUM> is located near the open end 161a1 of the front end part 161a of the release lever <NUM> as illustrated in <FIG>.

In the state in which the connection spring member <NUM> is thus attached to the release lever <NUM> in advance, the connecting end part <NUM> of the slide lever <NUM> is fitted on the outer side of the front end part 161a of the release lever <NUM>. When the open end 172a of the connecting end part <NUM> of the slide lever <NUM> abuts on the stopper 161f of the release lever <NUM>, the protruding engagement parts <NUM>, <NUM> of the connection spring member <NUM> protruding from the engagement protrusion holes 161e, 161e of the release lever <NUM> engage with the engagement holes 172b, 172b of the connecting end part <NUM> of the slide lever <NUM>. Since the rear sides 183b, 183b of the protruding engagement parts <NUM>, <NUM> rise at a substantially right angle to the lines along the shaft parts <NUM>, <NUM>, the rear sides 183b, 183b engage with thickness portions of rear edges 172b1, 172b1 of the engagement holes 172b, 172b at a substantially right angle. Consequently, without an operation of pushing the protruding engagement parts <NUM>, <NUM>, the connected slide lever <NUM> cannot be removed only by being pulled forward. Then, rattling especially in the left-right direction of the front end part <NUM> of the release lever <NUM> in the connecting end part <NUM> of the slide lever <NUM> is reduced owing to the elastic force of the shaft parts <NUM>, <NUM> in the separating direction.

Further, when the release lever <NUM> is inserted into the connecting end part <NUM>, the acting end 182a of the front lock part <NUM> receives force in such a direction as to be pressed toward the wire parts <NUM>, <NUM>, so that the restoring force of the front lock part <NUM> works in such a direction as to cause the acting end 182a to pivot up on the bent end 181a, to press the inner surface of the connecting end part <NUM>. This reduces the rattling of the release lever <NUM> especially in the up-down direction in the connecting end part <NUM>. Further, the bent end 181a of the connection spring member <NUM> has a thickness only corresponding to the thickness of the single wire part <NUM>, but since the front lock part <NUM> is inclined so as to be gradually separate from the wire parts <NUM>, <NUM> as it goes more rearward from the bent end 181a, the insertion of the front end part 161a of the release lever <NUM> into the open end 172a of the connecting end part <NUM> is very easy.

In the above-described manner, the left and right connecting end parts <NUM>, <NUM> of the slide lever <NUM> are connected to the front end parts 161a, 161a of the left and right release levers <NUM>, <NUM>, and being connected with the connection spring members <NUM> therebetween, they can be easily connected only by the insertion. In addition, the connection spring member <NUM> is formed of the worked wire material for springs, the protruding engagement parts <NUM>, <NUM> engage with both the front end parts 161a, 161a of the release lever <NUM> and the connecting end part <NUM> of the slide lever <NUM> through the engagement protrusion holes 161e, 161e and the engagement holes 172b, 172b, and the front lock part <NUM> provided at the position the predetermined distance apart from the protruding engagement parts <NUM>, <NUM> presses the inner surface of the connecting end part <NUM>. This reduces the rattling of the release levers <NUM>, <NUM> in the connecting end parts <NUM>, <NUM> of the slide lever <NUM> in any of the up, down, left, and right directions.

Further, the connection spring member <NUM> is disposed without the shaft parts <NUM>, <NUM> from the protruding engagement parts <NUM>, <NUM> up to the front lock part <NUM> being fixed to any place. Therefore, elastic force corresponding to the separation distance between the protruding engagement parts <NUM>, <NUM> and the front lock part <NUM> is exhibited. Specifically, if the middle portions of the shaft parts <NUM>, <NUM> are fixed to some places, a practical spring constant is higher than in the case they are not fixed, but in this embodiment, this is not the case. Accordingly, vibration accompanying an impact caused by the engagement of the engagement hole 162b of the lock plate <NUM> with the mating engagement part 11e of the lower rail <NUM> is absorbed, and abnormal noise due to the impact is also reduced.

It should be noted that the present invention is not limited to the above-described embodiment. What is essential in the present invention is that the connecting structure between the connecting end part of the slide lever and the front end part of the release lever uses the above-described connection spring member, and the detailed structure of the locking mechanism, the structures of the lower rail and the upper rail, and the structures of the sliding resistance reducing members and so on which are described above are merely examples. Further, the shape of the slide lever is not limited either. For example, as illustrated in <FIG>, it is also possible to use a slide lever <NUM> whose operation part <NUM> has a shorter lateral-direction length than in the type illustrated in <FIG> and <FIG>, and in which the operation part <NUM> and connecting end parts <NUM>, <NUM> are connected by oblique sides <NUM>, <NUM> that extend rearward toward the connecting end parts <NUM>, <NUM>. This slide lever <NUM> is shaped such that its range protruding more forward than the front edge of the seat cushion frame S1 is narrow, that is, the range of the oblique sides <NUM>, <NUM> is closer to the front edge of the seat cushion frame S1. This structure reduces a possibility that the slide lever <NUM> comes into contact with the legs of the person at the time of impact or the like. Note that the connecting structure between the connecting end parts <NUM>, <NUM> and the release levers <NUM>, <NUM> is completely the same as above.

Claim 1:
A seat sliding device (<NUM>) comprising:
a lower rail (<NUM>);
an upper rail (<NUM>) slidably provided on the lower rail (<NUM>) and connected to a seat frame (S);
a locking mechanism (<NUM>) including a lock plate (<NUM>) for locking the upper rail (<NUM>) at a predetermined position of the lower rail (<NUM>), a locking spring member (<NUM>) which biases the lock plate (<NUM>) in a locking direction, and a release lever (<NUM>) which operates the lock plate (<NUM>) in an unlocking direction; and
a slide lever (<NUM>) for operation connected to a front end part (161a) of the release lever (<NUM>),
characterized in that
wherein the slide lever (<NUM>) has a connecting end part (<NUM>) in a tubular shape, and the front end part (161a) of the release lever (<NUM>) is inserted in the connecting end part (<NUM>) with a connection spring member (<NUM>) therebetween,
wherein the connection spring member (<NUM>) is formed of a worked wire material for springs, is bent in the middle, and includes:
a bent end (181a) located forward;
two wire parts (<NUM>) extending rearward from the bent end (181a) and biased in such a direction as to separate from each other;
protruding engagement parts (<NUM>) which are formed to protrude outward in the respective two wire parts (<NUM>) at positions a predetermined distance apart from the bent end (181a) and, in a state in which the two wire parts (<NUM>) are inserted in the front end part (161a) of the release lever (<NUM>), protrude outward from engagement protrusion holes (161e) formed in the front end part (161a) at opposed positions; and
a front lock part (<NUM>) provided on the bent end (181a) side and having an acting end (182a) biased in such a direction as to be apart from the two wire parts (<NUM>), and
wherein the connecting end part (<NUM>) of the slide lever (<NUM>) has engagement holes (172b) formed at opposed positions, and is fitted on an outer side of the front end part (161a) of the release lever (<NUM>) while the protruding engagement parts (<NUM>) of the connection spring member (<NUM>) protruding from the engagement protrusion holes (161e) of the front end part (161a) of the release lever (<NUM>) engage with the engagement holes (172b) and an inner surface of the connecting end part (<NUM>) is pressed by elastic force of the acting end (182a) of the front lock part (<NUM>) of the connection spring member (<NUM>).