WO2018062076A1

WO2018062076A1 - Seat slide device

Info

Publication number: WO2018062076A1
Application number: PCT/JP2017/034465
Authority: WO
Inventors: Gyutaek Lee; Yoshitaka Negi; Kazuki TAMAKI; Hirotsugu Kuroda
Original assignee: Tf-Metal Co., Ltd.
Priority date: 2016-09-30
Filing date: 2017-09-25
Publication date: 2018-04-05

Abstract

In a lock member (117) disposed in a release lever (131), a fixation portion (119) is fixed to an upper-rail top wall (105a) of an upper rail (105) by a fixing member (115).　The release lever (131) swings in a front-rear direction about a swing pivot portion (151) for the lock member (117), and a release pressing portion (153) on the rear side presses the vicinity of lock teeth (125) of the lock member (117) downward to release lock to a lower rail (103).　In the lock member (117), a rear-side elastic deformation part (123) biases the lock teeth (125) in the lock direction, and a front-side elastic deformation portion (141) biases an operation handle (133) upward.　The lock member (117) is a plate spring member integrally including the fixation portion (119), the rear-side elastic deformation part (123), and the front-side elastic deformation portion (141).

Description

SEAT SLIDE DEVICE

　　　　The present invention relates to a seat slide device provided to a vehicle.

　　　　A seat slide device for a vehicle includes a lower rail fixed to a vehicle body and an upper rail fixed to a seat.　The upper rail is slidably attached to the lower rail.　The seat slide device is locked by engaging lock teeth of a lock member attached to the upper rail with lock notches of the lower rail.　A lock member disclosed in Patent Literature 1 is provided with a flange which is bent downward in front of a fixation portion for the upper rail, and which is provided with an opening, and an operation handle is inserted into this opening from the front side to have a leading end side thereof positioned above the lock member through a through-hole near the center of the lock member.　The lock member is an elastic member biased in a lock direction.　When the operation handle is operated upward, the leading end side moves the lock member downward, thereby releasing the lock.　The operation handle has a reduced diameter at a part thereof surrounded by the opening of the flange and includes a stopper at a leading end thereof, so that the operation handle is fixed in a front-rear direction relative to the lock member.

　　　　The seat slide device disclosed in Patent Literature 1 is very poor in assembly performance because the operation handle needs to be inserted deeply inside a gap space to engage the operation handle with the lock member, and each of leading ends of the operation handle needs to be inserted through the two holes on the lock member.　In addition, in Patent Literature 1, the operation handle directly rotates the lock member, which does not allow the operation handle to turn at a large operation angle.　In Patent Literatures 2 and 3, unlike Patent Literature 1 in which the operation handle also serves as a release lever, the operation handle is provided separately from a lock release lever but is coupled with the lock release lever near a rail front end part.

　　　　[PTL 1] Japanese Patent Application Publication No. 9-104266
　　　　[PTL 2] Japanese Patent Application Publication No. 2011-230715
　　　　[PTL 3] Japanese Patent Application Publication No. 2012-126184

　　　　However, in the techniques disclosed in Patent Literatures 2 and 3, the operation handle is coupled with an end part of the lock release lever.　This configuration requires separately provided biasing members, one of which biases the lock member in the lock direction, the other of which biases the operation handle upward, which leads to increase in the number of components.

　　　　Thus, the present invention is intended to achieve reduction in the number of components by integrating a biasing member that biases a lock member in a lock direction and a biasing member that biases an operation handle.

　　　　The present invention includes: a lower rail extending in a vehicle front-rear direction; an upper rail configured to relatively move in a longitudinal direction of the lower rail; a lock member attached to the upper rail and including a lock portion biased in a lock direction in which the lock portion comes into engagement with a lock receiving portion provided to the lower rail; a release lever; and an operation handle.　The release lever includes: a release pressing portion provided at a position of overlapping with the lock member in a longitudinal direction of the upper rail and capable of pressing a part of the lock member around the lock portion to release engagement of the lock portion with the lock receiving portion; an actuation portion actuated by a lock release operation of the operation handle; and a swing pivot portion provided between the release pressing portion and the actuation portion.　The operation handle is disposed below the actuation portion of the release lever and supported on a front side of the swing pivot portion of the release lever so as to be rotatable relative to the upper rail and configured to actuate the actuation portion of the release lever.　The lock member is a plate spring integrally including a base part including the swing pivot portion and fixed to the upper rail; a rear-side biasing part positioned on a rear side of the base part and configured to bias the lock portion in the lock direction; and a front-side biasing part positioned on the front side of the base part and configured to bias the operation handle upward and set to have biasing force weaker than biasing force of the rear-side biasing part.

　　　　According to the present invention, a lock member is a plate spring integrally including a biasing member that biases in a lock direction and a biasing member that biases an operation handle, thereby achieving reduction in the number of components.

FIG. 1 is a perspective view illustrating a state in which a lock member, a release lever, and an operation handle are assembled with an upper rail in a seat slide device according to a second embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. 1. FIG. 3 is a plan view illustrating the upper rail illustrated in FIG. 2 at a section taken along line A-A. FIG. 4 is a cross-sectional view illustrating lower and upper guide balls disposed between the upper rail and a lower rail. FIG. 5 is a perspective view of a ball retainer including the lower and upper guide balls illustrated in FIG. 4, and the lower rail. FIG. 6 is a perspective view of the upper rail. FIG. 7 is a perspective view of the lock member. FIG. 8 is a perspective view of the release lever. FIG. 9 is a front view of the release lever when viewed from the front side. FIG. 10 is a perspective view illustrating a state in which the lock member is assembled with the release lever, including the operation handle. FIG. 11 is a perspective view illustrating part of the operation handle. FIG. 12 is a cross-sectional view taken along line B-B, omitting illustration of the upper rail and the lock member illustrated in FIG. 2. FIG. 13 is a side view illustrating a recess formed on a sidewall of the upper rail. FIG. 14 is a perspective view illustrating a state in which a lock member, a release lever, and an operation handle are assembled with an upper rail in a seat slide device according to a first embodiment of the present invention. FIG. 15 is a cross-sectional view of FIG. 14. FIG. 16 is a plan view illustrating the upper rail illustrated in FIG. 15 at a section taken along line C-C. FIG. 17 is a cross-sectional view illustrating lower and upper guide balls disposed between the upper rail and a lower rail. FIG. 18 is a perspective view of a ball retainer including the lower and upper guide balls illustrated in FIG. 17, and the lower rail. FIG. 19 is a perspective view of the upper rail. FIG. 20 is a perspective view of the lock member. FIG. 21A is a perspective view of a fixing member. FIG. 21B is a side view of the fixing member. FIG. 22A is an enlarged view of part D in FIG. 15. FIG. 22B is a cross-sectional view taken along line E-E in FIG. 22A. FIG. 23A is a perspective view of the release lever. FIG. 23B is a plan view of the release lever. FIG. 23C is a side view of the release lever. FIG. 23D is a front view of the release lever when viewed from the front side. FIG. 24 is a perspective view illustrating a state in which the lock member is assembled with the release lever, including the operation handle. FIG. 25A is a perspective view of the operation handle. FIG. 25B is a plan view illustrating part of the operation handle. FIG. 25C is a side view of the operation handle. FIG. 25D is a cross-sectional view taken along line F-F in FIG. 25C. FIG. 25E is a cross-sectional view taken along line G-G in FIG. 25C.

　　　　Embodiments of the present invention will be described based on the accompanying drawings.

　　　　A seat slide device 101 according to a first embodiment of the present invention illustrated in FIGS. 14 to 17 is a manual slide device for manually adjusting a seat of a vehicle in a front-rear direction.　The seat slide device 101 is installed on a floor surface of the vehicle and includes a lower rail 103 extending in the vehicle front-rear direction, and an upper rail 105 installed on a back surface of a seat bottom (not illustrated) and assembled to be relatively movable inside of the lower rail 103 in a longitudinal direction of the lower rail 103.　Rail bodies 106 are each composed of the lower rail 103 and the upper rail 105, and provided in a pair on right and left sides.　FIG. 16 omits illustration of the lower rail 103.　In the following description, "front" means a vehicle front side on the left side in FIGS. 15 and 16, and "rear" means a vehicle rear side on the right side in FIGS. 15 and 16.

　　　　As illustrated in FIG. 17, the lower rail 103 includes a lower-rail bottom wall 103a shaped in a rectangular plate extending in the vehicle front-rear direction.　A pair of right and left lower-rail outer walls 103b extend upward from both end edges of the lower-rail bottom wall 103a in a vehicle width direction and tilt slightly outward.　Lower-rail inclined walls 103c are provided between lower ends of the pair of right and left lower-rail outer walls 103b and the lower-rail bottom wall 103a.　A pair of right and left lower-rail upper walls 103d extending closer to each other in parallel to the lower-rail bottom wall 103a are provided from upper end edges of the pair of right and left lower-rail outer walls 103b.

　　　　A pair of right and left lower-rail inner sidewalls 103e droop downward from inner end edges of the pair of right and left lower-rail upper walls 103d toward the lower-rail bottom wall 103a.　An interval between the lower-rail inner sidewalls 103e facing to each other in parallel is set so that the upper rail 105 being housed in the lower rail 103 is movable.

　　　　The upper rail 105 includes an upper-rail top wall 105a shaped in a rectangular plate extending in the vehicle front-rear direction.　A pair of right and left upper-rail sidewalls 105b droop downward from both end edges of the upper-rail top wall 105a in the vehicle width direction.　Upper-rail lower inclined walls 105c extend obliquely upward and outward from lower end edges of the upper-rail sidewalls 105b.　Upper-rail upper inclined walls 105e extend obliquely upward toward the lower-rail upper walls 103d through bent portions 105d from upper end edges of the pair of right and left upper-rail lower inclined walls 105c.

　　　　Lower arc parts 103f are provided between the lower-rail bottom wall 103a and the lower-rail inclined walls 103c of the lower rail 103.　Lower guide balls 107 are disposed to freely roll between the lower arc parts 103f and the upper-rail lower inclined walls 105c of the upper rail 105.　Upper arc parts 103g are provided between the lower-rail outer walls 103b and the lower-rail upper walls 103d of the lower rail 103.　Upper guide balls 109 are disposed to freely roll between the upper arc parts 103g and the upper-rail upper inclined walls 105e of the upper rail 105.

　　　　As illustrated in FIG. 18, the lower guide balls 107 and the upper guide balls 109 are rotatably supported by a ball retainer 111 not illustrated in FIG. 17.　The ball retainer 111 supports a total of four of the two lower guide balls 107 and the two upper guide balls 109.　When supporting the lower guide balls 107 and the upper guide balls 109, the ball retainer 111 is disposed at each of two front and rear places in housing spaces 113 (FIG. 17) enclosed by the lower-rail outer walls 103b, the lower-rail inclined walls 103c, the lower-rail upper walls 103d, and the lower-rail inner sidewalls 103e, and is disposed at a total of four places for the pair of right and left rail bodies 106.

　　　　As illustrated in FIG. 15, a lock member 117 is fixed to the upper-rail top wall 105a on the front side of the upper rail 105 by a fixing member 115 such as a rivet.　The lock member 117 is a plate spring member.　The lock member 117 includes, at a fixation portion 119 to be fixed by the fixing member 115, a fixation hole 119a into which the fixing member 115 is inserted.　A part around a fixation hole 105f on the upper-rail top wall 105a of the upper rail 105 is recessed lower than the other part of the upper-rail top wall 105a.　With this configuration, a head of the fixing member 115 does not protrude from the other part of an upper surface of the upper-rail top wall 105a of the upper rail 105.

　　　　FIGS. 21A and 21B illustrate the fixing member 115 before attachment.　As illustrated in FIG. 22A, which is an enlarged view of part D illustrated in FIG. 15, the fixing member 115 includes an insertion shaft portion115a to be inserted into the

fixation holes

119a and 105f from below, a large-diameter portion 115b provided below the insertion shaft portion115a and having a diameter larger than that of the insertion shaft portion115a, and a flange portion 115c provided below the large-diameter portion 115b and opposite to the insertion shaft portion115a.　The flange portion 115c is a protrusion that protrudes toward sides.

　　　　As illustrated in FIG. 22A and FIG. 22B, which is a cross-sectional view taken along line E-E in FIG. 22A, the flange portion 115c is positioned below latch protrusions 147e provided to right and left sidewalls 147 of a release lever 131 illustrated in FIG. 23A to be described later.　As illustrated in FIG. 23A, the latch protrusions 147e are positioned slightly on the front side of a central position in the front-rear direction, and formed by cutting inward from the sidewalls 147 as parts of the release lever 131.

　　　　As illustrated in FIG. 22B, the latch protrusions 147e have upper parts connected with the sidewalls 147 and lower parts disconnected from the sidewalls 147.　Lower end surfaces 147e1 at the disconnection face to an upper surface 115c1 of the flange portion 115c.　A gap T is provided between each of the lower end surfaces 147e1 and the upper surface 115c1.　The gap T allows swing in the front-rear direction about a swing pivot portion 151 at part of the release lever 131, at which the fixing member 115 is provided.

　　　　The fixation portion 119 of the lock member 117 illustrated in FIG. 20 extends in the front-rear direction substantially in parallel to the upper-rail top wall 105a illustrated in FIG. 15.　A rear-side tilted part 121 tilted obliquely downward toward the rear side is provided from a rear end of the fixation portion 119.　A rear-side elastic deformation part 123 extending toward the rear side substantially in parallel to the fixation portion 119 is provided from a rear end of the rear-side tilted part 121.　As illustrated in FIGS. 16 and 20, a total of six lock teeth 125, three on each side, as lock portions protruding toward right and left sides are provided at substantially equal intervals in the front-rear direction at a rear end part 123a of the rear-side elastic deformation part 123.

　　　　As illustrated in FIG. 19, lock-tooth fitting holes 129 are provided through the right and left upper-rail sidewalls 105b and the upper-rail lower inclined walls 105c at three places on each of the right and left sides in the front-rear direction near a substantially central part of the upper rail 105 in the front-rear direction.　As illustrated in FIG. 15, the lock teeth 125 of the lock member 117 are fitted into the lock-tooth fitting holes 129 from below.

　　　　As illustrated in FIG. 18, a plurality of lock notches 127 as lock receiving portions are provided at positions on the lower rail 103 in the front-rear direction except for vicinities of front and rear parts of the right and left lower-rail inner sidewalls 103e.　The lock member 117 is locked to the lower rail 103 when the lock teeth 125 of the lock member 117 being positioned in the lock-tooth fitting holes 129 are placed into the lock notches 127 from below.　In this state, the upper rail 105, to which the lock member 117 is attached, is restricted in movement relative to the lower rail 103 in the front-rear direction.

　　　　Upward elastic force applied by the rear-side elastic deformation part 123 while the lock member 117 is attached to the upper rail 105 maintains the state in which the lock teeth 125 are fitted in the lock notches 127.　In this state, when an operation handle 133 illustrated in FIG. 15 is operated upward, the rear end part 123a of the lock member 117 is biased downward through the release lever 131 to release lock.　The operation handle 133 is inserted into the upper rail 105 from the front side and disposed to operate with the release lever 131 in a coupled manner.

　　　　As illustrated in FIGS. 16 and 20, the lock member 117 includes protruding portions 119b as support receiving portions protruding toward sides from right and left sides at a position corresponding to the fixation hole 119a of the fixation portion 119.　The protruding portions 119b protrude toward sides at thicknesses same as the plate thickness of the lock member 117 including the fixation portion 119, and have rectangular shapes in plan view.　As illustrated in FIGS. 15 and 20, the lock member 117 includes a front-side first tilted portion 135 on the front side, which is a side of the fixation portion 119 opposite to the rear-side tilted part 121.　The front-side first tilted portion 135 is tilted lower further on the front side.

　　　　An operation-handle receiving portion 137 extends substantially in parallel to the fixation portion 119 from a front end (lower end) of the front-side first tilted portion 135 toward the front side.　A front-side second tilted portion 139 extends obliquely downward from a front end of the operation-handle receiving portion 137 toward the front side.　Leading end parts 167a of arm portions 167 of the operation handle 133, which are to be described later, are each placed in contact with an upper surface of the operation-handle receiving portion 137.　A front-side elastic deformation portion 141 extends substantially in parallel to the operation-handle receiving portion 137 from a front end of the front-side second tilted portion 139 toward the front side.

　　　　A front-end click portion 145 bent upward is provided at a front end of the front-side elastic deformation portion 141.　As illustrated in FIGS. 15 and 24, the front-end click portion 145 is engaged from below with a recess 133a provided on a lower surface of the operation handle 133.　The front-side elastic deformation portion 141 presses the recess 133a upward through the front-end click portion 145.　Pressing force applied on the recess 133a by the front-side elastic deformation portion 141 is set weaker than pressing force applied on the lock notches 127 by the lock teeth 125 of the rear-side elastic deformation part 123.　This configuration keeps a lower part of a leading end of the operation handle 133 in contact with the operation-handle receiving portion 137 of the lock member 117.

　　　　As illustrated in FIG. 15, the front side of a substantially central part of the front-side elastic deformation portion 141 in the front-rear direction protrudes out of the upper rail 105 toward the front side when the lock member 117 is attached to the upper rail 105.

　　　　As illustrated in FIGS. 23A to 23D, the release lever 131 includes the right and left sidewalls 147, and an upper wall 149 connecting upper ends of the right and left sidewalls 147 in a region near rear end parts of the right and left sidewalls 147.　Except for the vicinities of front and rear parts, the lock member 117 is disposed between the right and left sidewalls 147 of the release lever 131.　In other words, the release lever 131 is provided overlapping with the lock member 117 in longitudinal and vertical directions of the upper rail 105.

　　　　Recessed parts 147a as support portions are provided at upper end parts of the sidewalls 147 on the front side of a middle position on the release lever 131 in the front-rear direction.　The recessed parts 147a are positioned above the latch protrusions 147e and shaped in curved recess arcs having opened upper parts.　As illustrated in FIG. 24, the recessed parts 147a are disposed below the right and left protruding portions 119b of the lock member 117, and engaged with lower parts of the protruding portions 119b.　The protruding portions 119b of the lock member 117 and the recessed parts 147a of the release lever 131 serve as the swing pivot portion 151 when front and rear parts of the release lever 131 vertically swing.　The swing pivot portion 151 coincides with a fixation site of the lock member 117 to the upper rail 105 in the front-rear direction.

　　　　The release lever 131 includes a release pressing portion 153 extending toward the rear side from the upper wall 149.　A curved convex portion 153a protruding downward is provided at a lower part of a leading end of the release pressing portion 153.　The curved convex portion 153a contacts an upper surface of the rear end part 123a of the rear-side elastic deformation part 123 in the lock member 117.　A protrusion 149a formed by upward cutting is provided on the upper wall 149.　The protrusion 149a functions as a stopper configured to contact the upper-rail top wall 105a of the upper rail 105 when the release lever 131 swings about the swing pivot portion 151 in the anticlockwise direction in FIG. 15.

　　　　A front-part upper wall 157 connects upper ends at a front end part of the release lever 131.　Cutout portions 147f are provided at front-end lower parts of the right and left sidewalls 147.　Bent pieces 147g are provided at upper parts of the right and left cutout portions 147f and bent to protrude from the sidewalls 147 toward sides facing to each other.　Leading ends of the right and left bent pieces 147g are separated from each other to form a gap therebetween.　Restriction protrusions 147h that restrict downward movement of the operation handle 133 are provided at front-end lower parts of the right and left sidewalls 147 of the release lever 131 on the rear side of the cutout portions 147f.

　　　　The bent pieces 147g serve as acting portions (actuation portions 159) to which force of rotational operation of the operation handle 133 upward in a lock release direction is applied from below.　In other words, the release lever 131 includes the acting portions (actuation portions 159) to which the force of operation of the operation handle 133 is applied, on the front side opposite to the release pressing portion 153 on the rear side of the swing pivot portion 151.　The actuation portions 159 are composed of the bent pieces 147g, the restriction protrusions 147h, and first convex portions 147c as pressed-in portions to be described later.　The actuation portions 159 of the release lever 131 are positioned on the front side opposite to the release pressing portion 153 on the rear side of the swing pivot portion 151.

　　　　As illustrated in FIG. 25A, the operation handle 133 has a substantially U shape as a whole and includes the pair of right and left arm portions 167 provided respectively for the pair of right and left rail bodies 106 illustrated in FIG. 14, and a grasping portion 168 connecting the pair of arm portions 167 and extending in the vehicle width direction.　The pair of arm portions 167 extend in the front-rear direction and are inserted in the right and left upper rails 105 through front ends thereof.　The grasping portion 168 is grasped by a passenger operating the operation handle 133.

　　　　As illustrated in FIGS. 15 and 24, rear end parts of the arm portions 167 are inserted between the right and left sidewalls 147 of the release lever 131, and as described above, each leading end part 167a on the rear side contacts the upper surface of the operation-handle receiving portion 137 of the lock member 117.　The arm portions 167 including the grasping portion 168 are entirely made of a cylinder member, and parts on the rear side of places where the recesses 133a described above are provided serve as operation portions 169 each having a shape obtained by vertically squeezing the cylinder member.

　　　　As illustrated in FIGS. 25A to 25E, in each operation portion 169, a middle part 169b on the front side of a rear end part 169a has a section substantially in a hat shape.　Specifically, the middle part 169b includes an upper surface 169b1, side surfaces 169b2 extending downward from right and left end parts of the upper surface 169b1, and flanges 169b3 extending substantially in parallel to the upper surface 169b1 toward right and left sides from lower ends of the right and left side surfaces 169b2.　A lower part of the hat shape is opened to serve as a housing recess 170 for housing the front-side elastic deformation portion 141 of the lock member 117.

　　　　The flanges 169b3 are inserted between the bent pieces 147g and between the restriction protrusions 147h in the release lever 131.　In this state, force of upward operation of the operation handle 133 is applied to lower surfaces of the bent pieces 147g from below through the flanges 169b3.　An interval between the right and left bent pieces 147g is larger than an interval between the right and left side surfaces 169b2 of the hat-shaped middle part 169b so that parts where the side surfaces 169b2 positioned above the flanges 169b3 are provided can be placed between the right and left bent pieces 147g.

　　　　As illustrated in FIGS. 25D and 25E, in the middle part 169b of each operation portion 169, the upper surface 169b1 has a width (width in the vertical direction in FIG. 25B) larger at a front end part into which the front-end click portion 145 of the lock member 117 is placed, and smaller on the rear side of the front end part.　The rear end part 169a of each operation portion 169 includes a rear-end upper surface 169a1 and a rear-end side surface 169a2 but includes no flange, and has a substantially inverted U shape having a downward opening.　The rear-end upper surface 169a1 has a width (width in the vertical direction in FIG. 25B) substantially equal to that of the upper surface 169b1 in a part illustrated in FIG. 25D and larger than the width (width in the vertical direction in FIG. 25C) of each side surface 169b2.

　　　　As illustrated in FIGS. 23A and 23B, the release lever 131 includes the first convex portions 147c at positions facing to each other on the rear side of the rear end part 169a of the operation portion 169.　The first convex portions 147c protrude inward from the sidewalls 147 of the release lever 131 by cutting, and is slightly separated from an end face of the rear end part 169a in an assembled state of the operation handle 133 in which the front-end click portion 145 is engaged with the recess 133a.　Second convex portions 147d protruding inward from the sidewalls 147 are provided at upper parts of the sidewalls 147 on the front side of the first convex portions 147c.　In a hold state in which the operation handle 133 is not operated, the second convex portions 147d are provided above the flanges 169b3 and separated from the flanges 169b3.

　　　　As illustrated in FIG. 24, the restriction protrusions 147h are positioned below the flanges 169b3 at a front end of the release lever 131.　When the grasping portion 168 of the operation handle 133 is pressed downward, the operation handle 133 swings in the anticlockwise direction in FIG. 15 with the restriction protrusions 147h as pivots while elastically deforming the front-side elastic deformation portion 141.　Simultaneously, the leading end parts 167a are displaced upward, and the flanges 169b3 contacts the second convex portions 147d from below.　This restricts excess downward movement of the operation portion of the operation handle 133.　In this case, the latch portions 147e of the release lever 131 contact the flange portion 115c of the fixing member 115 and prohibits the recessed parts 147a from coming off the protruding portions 119b of the lock member 117, and the protrusion 149a provided to the upper wall 149 on the rear side contacts the upper-rail top wall 105a of the upper rail 105 from below and restricts swing of the release lever 131.

　　　　The following describes operation of the seat slide device 101 configured as described above.

　　　　FIGS. 14 to 16 illustrate a lock held state in which the lock teeth 125 of the lock member 117 are engaged and locked with the lock notches 127 of the lower rail 103.　In the state, when a passenger operates the operation handle 133 upward, the operation handle 133 swings upward with the leading end parts 167a as pivots since a lower surface of the leading end part 167a of each arm portion 167 are supported by the operation-handle receiving portion 137 of the lock member 117.　When the operation handle 133 is swung upward, the flanges 169b3 of each operation portion 169 press upward lower surfaces of the bent pieces 147g of the release lever 131 as actuation surfaces.

　　　　Accordingly, the release lever 131 swings about the swing pivot portion 151 in the anticlockwise direction in FIG. 15.　With the swing of the release lever 131, the curved convex portion 153a of the release pressing portion 153 on the rear side presses downward the rear end part 123a corresponding to a part around the lock portions of the lock member 117, and the rear-side elastic deformation part 123 elastically deforms downward.　As a result, the lock teeth 125 come off the lock notches 127 of the lower rail 103, and lock is released.　When lock is released, a seat (not illustrated) together with the upper rail 105 can be moved toward the front and rear sides relative to a floor surface of the vehicle on which the lower rail 103 is provided to a seat position desired by a passenger.

　　　　When the seat position is determined and the passenger releases the operation handle 133, the rear-side elastic deformation part 123 of the lock member 117 presses the release pressing portion 153 upward and swings the release lever 131 back to the lock held state illustrated in FIG. 15.　In this case, the release lever 131 swings about the swing pivot portion 151 in the anticlockwise direction in FIG. 15.

　　　　In the state illustrated in FIG. 15, it is assumed that, for example, the vehicle is hit from the rear side and a heel of the passenger collides with the operation handle 133 toward the rear side.　In this case, a load received by the operation handle 133 acts on the first convex portions 147c of the release lever 131 illustrated in FIGS. 15 and 16 through the rear end part 169a illustrated in FIG. 25A.　Upon reception of the load by the first convex portions 147c toward the rear side, the front-end click portion 145 comes off the recess 133a due to impact acting on the operation handle 133, and the operation handle 133 moves toward the rear side.　In this case, the recessed parts 147a of the release lever 131 at the swing pivot portion 151 come off the protruding portions 119b of the lock member 117 and move toward the rear side.

　　　　This reduces impact of the collision of the heel of the passenger with the operation handle 133.　When the operation handle 133 is moved to the rear side, a rear end of the rear-end upper surface 169a1 of each operation portion 169 contacts the front-side first tilted portion 135 of the lock member 117 illustrated in FIG. 15 and is prohibited from further moving toward the rear side.　When the rear end of the rear-end upper surface 169a1 of the operation handle 133 moves upward toward the rear side along the front-side first tilted portion 135, the leading end part 167a (the rear end of the rear-end upper surface 169a1) moves upward comes off a position facing to the first convex portions 147c.　Thus, the operation handle 133 can move farther toward the rear side than the release lever 131.　The release lever 131 does not move toward the rear side more than needed.

　　　　As illustrated in FIG. 24, the lock member 117 and the release lever 131 can be assembled with each other before assembled with the upper rail 105.　Since the release lever 131 has a lower part opened entirely in the longitudinal direction, the lock member 117 is inserted between the right and left sidewalls 147 through the opening of the lower part while being tilted.　When inserted to a position where the fixation portion 119 including the protruding portions 119b is higher than the sidewalls 147, the lock member 117 is set back to a horizontal orientation, and thereafter moved downward to allow the protruding portions 119b of the lock member 117 to enter into the recessed parts 147a of the release lever 131.

　　　　In this state, the curved convex portion 153a of the release pressing portion 153 contacts on the rear end part 123a of the lock member 117, and the front side of the vicinity of a central position on the front-side elastic deformation portion 141 in the front-rear direction and protrudes toward the front side from the release lever 131.　As illustrated in FIGS. 14 to 16, the lock member 117 and the release lever 131 thus assembled are placed between the right and left upper-rail sidewalls 105b of the upper rail 105, and the fixation portion 119 of the lock member 117 is fixed to the upper-rail top wall 105a of the upper rail 105 by the fixing member 115.　In this manner, the lock member 117 and the release lever 131 can be assembled with the upper rail 105 after assembled with each other in advance, thereby improving assembly performance.

　　　　When the lock member 117 and the release lever 131 are assembled with the upper rail 105, each operation portion 169 of the operation handle 133 is inserted through a front end opening of the release lever 131 while the front-side elastic deformation portion 141 of the lock member 117 is bent downward.

　　　　The operation handle 133 is inserted while the housing recess 170 is moved along the front-side elastic deformation portion 141.　The width of the front-end click portion 145 of the lock member 117 in the right and left direction is larger than the width of the housing recess 170 in the right and left direction.　With this configuration, the front-end click portion 145 slides below the housing recess 170 without engaging with the housing recess 170.　Then, as illustrated in FIGS. 15 and 24, each leading end part 167a reaches at the operation-handle receiving portion 137 through the front-side second tilted portion 139, and the front-end click portion 145 of the lock member 117 is inserted to a position corresponding to the recess 133a.　As a result, the front-end click portion 145 is engaged with the recess 133a, which completes the assembly.　As described above, the operation handle 133 only needs to be inserted into the release lever 131 while the front-side elastic deformation portion 141 of the lock member 117 is bent downward, thereby improving assembly performance for the operation handle 133.

　　　　The right and left sidewalls 147 of the release lever 131 are disposed along the right and left upper-rail sidewalls 105b of the upper rail 105, and the release pressing portion 153, the recessed parts 147a (swing pivot portion 151), and the actuation portions 159 are substantially linearly arranged in the front-rear direction.　With this configuration, the release lever 131 can have a reduced height in the vertical direction, and thus can be efficiently disposed in a narrow space inside the upper rail 105, thereby achieving downsizing of the entire device.

　　　　The lock member 117 according to the present embodiment includes: the fixation portion 119 including the swing pivot portion 151 and fixed to the upper rail 105; the rear-side elastic deformation part 123 positioned on the rear side of the fixation portion 119 and configured to bias the lock teeth 125 in a lock direction; and the front-side elastic deformation portion 141 positioned on the front side of the fixation portion 119, configured to bias the release lever 131 and the operation handle 133 upward, and set to exert biasing force weaker than that of the rear-side elastic deformation part 123.

　　　　With this configuration, in the present embodiment, a biasing member (the rear-side elastic deformation part 123) that biases the lock member 117 in the lock direction, and a biasing member (the front-side elastic deformation portion 141) that biases the operation handle 133 upward are achieved by an integrated spring member.　Accordingly, the number of components can be reduced as compared to a configuration in which these two biasing members are separately provided.

　　　　The release pressing portion 153 of the release lever 131 on the rear side is biased upward by the rear-side elastic deformation part 123 of the lock member 117.　Simultaneously, as illustrated in FIG. 24, the flanges 169b3 of the operation handle 133 contact the bent pieces 147g of the release lever 131 from below.　Accordingly, the bent pieces 147g of the release lever 131 are biased upward through the operation handle 133 (flanges 169b3), the recess 133a of which is biased upward by the front-side elastic deformation portion 141.

　　　　As described above, in the lock member 117, the rear-side elastic deformation part 123 having an upward biasing function is provided on the rear side, and the front-side elastic deformation portion 141 having an upward biasing function is provided on the front side.　With this configuration, the release lever 131 is swingably supported by the lock member 117 through the swing pivot portion 151 at a substantially central part in the front-rear direction.　In this manner, the two components of the lock member 117 and the release lever 131 can be assembled with each other as a unit before attached to the upper rail 105, thereby improving assembly performance.

　　　　In the present embodiment, the fixing member 115 is provided to fix the fixation portion 119 of the lock member 117 to a lower surface of the upper rail 105.　As illustrated in FIG. 22B, the fixing member 115 includes the flange portion 115c protruding in side directions on a side of the lock member 117 opposite to the upper-rail top wall 105a of the upper rail 105.　The side directions correspond to directions toward the sidewalls 147 of the release lever 131 in FIG. 22B.　The release lever 131 includes the latch protrusions 147e positioned above the flange portion 115c.

　　　　With this configuration, the release lever 131 receives downward force when the operation handle 133 is operated upward to swing the release lever 131 with the swing pivot portion 151 as a pivot or when the operation handle 133 is pressed downward.　Simultaneously, the latch protrusions 147e of the release lever 131 contact the flange portion 115c of the fixing member 115 from above.　This restricts downward movement of the release lever 131 near the swing pivot portion 151 and prohibits the recessed parts 147a of the release lever 131 from coming off the protruding portions 119b of the lock member 117.

　　　　The lock teeth 125 of the lock member 117 do not enter into the lock notches 127 of the lower rail 103, but mount on a lower surface between the lock notches 127 adjacent to each other in some cases.　In such a case, the release lever 131 does not receive upward biasing force by the rear-side elastic deformation part 123 of the lock member 117.　Simultaneously, the release lever 131 is prevented from moving downward since the latch protrusions 147e contacts the flange portion 115c from above.

　　　　In other words, the flange portion 115c of the fixing member 115 has a hold function of holding the release lever 131 by restricting downward movement.　This hold function is achieved only by providing the flange portion 115c to the fixing member 115 and providing the latch protrusions 147e to the release lever 131, and there is no need to redundantly provide a dedicated component having the hold function.　This leads to prevention of increase in the number of components.

　　　　The fixing member 115 is inserted from below in FIG. 15 to fix the lock member 117 to the upper rail 105.　In this case, the vicinities of the recessed parts 147a of the release lever 131 are temporarily supported by the flange portion 115c of the fixing member 115 through the latch protrusions 147e, which improves assembly performance.

　　　　In the present embodiment, the latch protrusions 147e are formed by cutting the sidewalls 147 as parts of the release lever 131.　In this manner, the latch protrusions 147e can be easily formed.

　　　　When operated upward, the operation handle 133 swings as the leading end part 167a of each arm portion 167 presses the operation-handle receiving portion 137 of the lock member 117 downward.　Since the lock member 117 includes a handle support portion (the operation-handle receiving portion 137) when the operation handle 133 is operated to swing, there is no need to redundantly provide a handle support portion to the upper rail, which leads to reduction of the number of components and reduction of the height of the upper rail.

　　　　In the lock member 117 according to the present embodiment, the fixation portion 119, the operation-handle receiving portion 137 as a handle support portion, and the front-side elastic deformation portion 141 are connected with each other in a stepped manner when viewed from side and extend in the front-rear direction.　When the fixation portion 119, the operation-handle receiving portion 137, and the front-side elastic deformation portion 141 are substantially in parallel to each other in the state illustrated in FIG. 15, the front-side elastic deformation portion 141 and the rear-side elastic deformation part 123 are elastically deformed to bias the front-end click portion 145 and the rear end part 123a upward.　Each operation portion 169 as a rear-side connection portion of the operation handle 133 has a section in a substantially inverted U shape, and the operation-handle receiving portion 137 of the lock member 117 is housed in the housing recess 170 of the operation portion 169, having a section in an inverted U shape, from below.

　　　　Thus, the lock member 117 can be formed by bending a plate spring member having a flat plate shape, and have a simplified structure, which facilitates manufacturing.　Since the operation-handle receiving portion 137 of the lock member 117 is housed in the housing recess 170, which has a section in an inverted U shape, of each operation portion 169 of the operation handle 133, the handle support portion (handle rotation center) of the operation handle 133 can be easily set on the front side of the swing pivot portion 151 of the release lever 131.　Since the operation-handle receiving portion 137 is housed in the housing recess 170, a reduced height in the vertical direction can be obtained where the operation handle 133 and the operation-handle receiving portion 137 of the lock member 117 overlap with each other.

　　　　In the present embodiment, the front end of the front-side elastic deformation portion 141 of the lock member 117 is provided with the front-end click portion 145 protruding upward at a position on the front side of the actuation portions 159 of the release lever 131.　The recess 133a, to which the front-end click portion 145 of the front-side elastic deformation portion 141 fits, is formed at a lower part of the operation handle 133.

　　　　With this configuration, since the front-end click portion 145 of the front-side elastic deformation portion 141 is fitted to the recess 133a of the operation handle 133 at a position on the front side of the actuation portions 159 of the release lever 131, the operation handle 133 can be prphibited from moving in an axial direction (the front-rear direction).　This prevents force of the operation handle 133 in the axial direction from directly acting on the release lever 131, thereby prohibiting the release lever 131 from moving in the axial direction.　When the operation handle 133 receives upward biasing force by the front-side elastic deformation portion 141, a leading end of each operation portion 169 is biased downward with the bent pieces 147g of the release lever 131 as pivots.　In this case, the bent pieces 147g of the release lever 131 are biased upward by the flanges 169b3 of the operation handle 133.　Accordingly, in the release lever 131, the recessed parts 147a and the protruding portions 119b of the swing pivot portion 151 are maintained being engaged with each other, and the leading end of the operation portion 169 of the operation handle 133 is maintained being pressed against the operation-handle receiving portion 137.

　　　　The front-side elastic deformation portion 141 of the lock member 117 extends in parallel to the housing recess 170 of the operation handle 133.　With this configuration, when the operation handle 133 is operated upward, the front-side elastic deformation portion 141 biasing the operation handle 133 upward is moved with the operation handle 133.　In this manner, the front-end click portion 145 and the front-side elastic deformation portion 141 are positioned below the operation handle 133, and do not protrude outside, thereby achieving high safety.

　　　　In the present embodiment, the front-end click portion 145 of the front-side elastic deformation portion 41 of the lock member 117 is positioned on the front side of a front end of the upper rail 105.　With this configuration, when the operation handle 133 is assembled, the front-side elastic deformation portion 141 protruding on the front side can be easily moved downward, and in this state, the operation handle 133 can be easily inserted into the release lever 131.

　　　　In the present embodiment, when the grasping portion 168 on the front side receives a downward load, the operation handle 133 swings in the anticlockwise direction in FIG. 15 with the restriction protrusions 147h as pivots while bending the front-side elastic deformation portion 141.　In this case, the rear-end upper surface 169a1 of each operation portion 169 (the leading end part 167a of the arm portion 167) is moved upward and separated from the operation-handle receiving portion 137 of the lock member 117, and a leading end of the rear end part 169a is shifted from the first convex portions 147c in the vertical direction.

　　　　Accordingly, when the operation handle 133 is pressed downward and the operation handle 133 receives a load toward the rear side, any effect of this load on the release lever 131 can be avoided to prevent the release lever 131 from moving toward the rear side.　When the rear-end upper surface 169a1 of each operation portion 169 (the leading end part 167a of the arm portion 167) is moved upward and separated from the operation-handle receiving portion 137 of the lock member 117, the flanges 169b3 contact the second convex portions 147d from below, thereby preventing excess swing of the operation handle 133.　Such an effect of preventing excess swing of the operation handle 133 is achieved when the upper rail 105 protrudes on the front side of the lower rail 103.

　　　　The swing pivot portion 151 according to the present embodiment can be set substantially in the thickness of the lock member 117 as a plate spring, thereby achieving a smaller swing pivot structure.

　　　　When the release lever 131 receives impact and is moved toward the rear side, the recessed parts 147a come off the protruding portions 119b.　In this case, the release lever 131 is moved downward only by the gap T and the recessed parts 147a and the protruding portions 119b plastically deform only by slight amounts, and thus force that rotates the release lever 131 in the lock release direction is extremely small.　With this configuration, the release lever 131 can be prevented from pressing the lock member 117 downward when the recessed parts 147a come off the protruding portions 119b, thereby more reliably preventing lock release.

　　　　A load at which the recessed parts 147a come off the protruding portions 119b can be easily set by changing the shape of the recessed parts 147a or the shape of the protruding portions 119b.　For example, the lower parts of the protruding portions 119b may have curved surface shapes that are convex downward in accordance with the curved surface shapes of the recessed parts 147a.　The recessed parts 147a may each have a plane bottom part and tilted surfaces on the front and rear sides of the plane bottom part.

　　　　When the recessed parts 147a come off the protruding portions 119b, the release lever 131 moves downward and the latch protrusions 147e contacts the flange portion 115c of the fixing member 115.　However, a load received by the release lever 131 toward the rear side in this case is extremely large.　Thus, the recessed parts 147a come off the protruding portions 119b, for example, through deformation of the latch protrusions 147e.

　　　　A seat slide device 1 according to a second embodiment of the present invention illustrated in FIGS. 1 to 4 is of a manual type for manually adjusting a vehicle seat in the front-rear direction.　The seat slide device 1 includes a lower rail 3 installed on a floor surface of a vehicle and extending in a vehicle front-rear direction, and an upper rail 5 installed on a back surface of a seat bottom (not illustrated) and assembled to be relatively movable inside the lower rail 3 in a longitudinal direction of the lower rail 3.　The lower rail 3 and the upper rail 5 serve as a rail body 6, and the rail bodies 6 are provided in a pair on right and left sides.　FIGS. 2 and 3 omit illustration of the lower rail 3.　In the following description, "front" means a vehicle front side on the left side in FIGS. 2 and 3, and "rear" means a vehicle rear side on the right side in FIGS. 2 and 3.

　　　　As illustrated in FIG. 4, the lower rail 3 includes a lower-rail bottom wall 3a shaped in a rectangular plate extending in the vehicle front-rear direction.　A pair of right and left lower-rail outer walls 3b extend upward from both end edges of the lower-rail bottom wall 3a in the vehicle width direction and tilt slightly outward.　Lower-rail inclined walls 3c extending obliquely upward closer to each other are provided from upper end edges of the pair of right and left lower-rail outer walls 3b.　A pair of right and left lower-rail upper walls 3d extending closer to each other in parallel to the lower-rail bottom wall 3a are provided from upper ends of the lower-rail inclined walls 3c.

　　　　A pair of right and left lower-rail inner sidewalls 3e droop downward from inner end edges of the pair of right and left lower-rail upper walls 3d toward the lower-rail bottom wall 3a.　An interval between the lower-rail inner sidewalls 3e facing to each other in parallel is set so that the upper rail 5 being housed in the lower rail 3 is movable.

　　　　The upper rail 5 includes an upper-rail top wall 5a shaped in a rectangular plate extending in the vehicle front-rear direction.　A pair of right and left upper sidewalls 5b droop downward from both end edges of the upper-rail top wall 5a in the vehicle width direction.　Upper-rail lower inclined walls 5c extend obliquely upward and outward from lower end edges of the upper sidewalls 5b.　Upper-rail upper inclined walls 5e extend obliquely upward toward the lower-rail inclined walls 3c through bent portions 5d from upper end edges of the pair of right and left upper-rail lower inclined walls 5c.

　　　　Lower arc parts 3f are provided between the lower-rail bottom wall 3a and the lower-rail outer walls 3b of the lower rail 3.　Lower guide balls 7 are disposed to freely roll between the lower arc parts 3f and the upper-rail lower inclined walls 5c of the upper rail 5.　Upper arc parts 3g are provided between the lower-rail outer walls 3b and the lower-rail inclined walls 3c of the lower rail 3.　Upper guide balls 9 are disposed to freely roll between the upper arc parts 3g and the upper-rail upper inclined walls 5e of the upper rail 5.

　　　　As illustrated in FIG. 5, the lower guide balls 7 and the upper guide balls 9 are rotatably supported by a ball retainer 11 not illustrated in FIG. 4.　The ball retainer 11 supports a total of four of the two lower guide balls 7 and the two upper guide balls 9.　When supporting the lower guide balls 7 and the upper guide balls 9, the ball retainer 11 is disposed at each of two places of front and rear places in housing spaces 13 (FIG. 4) enclosed by the lower-rail outer walls 3b, the lower-rail inclined walls 3c, the lower-rail upper walls 3d, and the lower-rail inner sidewalls 3e, and is disposed at a total of four places for the pair of right and left rail bodies 6.　FIGS. 1 to 3 omit illustration of the lower guide balls 7, the upper guide balls 9, and the ball retainer 11.

　　　　As illustrated in FIGS. 2 and 3, a lock member 17 is fixed to the upper-rail top wall 5a on the front side of the upper rail 5 by a fixing member 15 such as a rivet.　The lock member 17 is a plate spring member.　The lock member 17 includes, at a fixation portion 19 to be fixed by the fixing member 15, a fixation hole 19a into which the fixing member 15 is inserted.　A pair of slits are provided along parts where the upper-rail top wall 5a is coupled with the upper sidewalls 5b with a fixation hole 5f sandwiched therebetween on the upper-rail top wall 5a of the upper rail 5.　A part around the fixation hole 5f on the upper-rail top wall 5a is recessed lower than the other part of the upper-rail top wall 5a.　With this configuration, a head of the fixing member 15 does not protrude from the other part of an upper surface of the upper-rail top wall 5a of the upper rail 5.

　　　　The fixation portion 19 includes a rear-side tilted part 21 extending in the front-rear direction substantially in parallel to the upper-rail top wall 5a and tilting obliquely downward toward the rear side from a rear end of the fixation portion 19.　A rear-side elastic deformation part 23 extends from a rear end of the rear-side tilted part 21 toward the rear side substantially in parallel to the fixation portion 19.　As illustrated in FIGS. 3 and 7, a total of six lock teeth 25, three on each side, as lock portions protruding toward right and left sides are provided at substantially equal intervals in the front-rear direction a rear end part 23a of the rear-side elastic deformation part 23.

　　　　As illustrated in FIG. 6, lock-tooth fitting holes 29 are provided through the right and left upper sidewalls 5b and the upper-rail lower inclined walls 5c at three places on each of the right and left sides in in the front-rear direction near a substantially central part of the upper rail 5 in the front-rear direction.　As illustrated in FIGS. 2 and 3, the lock teeth 25 of the lock member 17 are fitted into the lock-tooth fitting holes 29 from below.

　　　　As illustrated in FIG. 5, a plurality of lock notches 27 as lock receiving portions are provided at positions on the right and left lower-rail inner sidewalls 3e of the lower rail 3 in the front-rear direction except for vicinities of front and rear parts.　The lock member 17 is locked to the lower rail 3 when the lock teeth 25 of the lock member 17 being positioned in the lock-tooth fitting holes 29 enter into the lock notches 27 from below.　In this state, the upper rail 5, to which the lock member 17 is attached, is prohibited from moving relative to the lower rail 3 in the front-rear direction.

　　　　Upward elastic force applied by the rear-side elastic deformation part 23 while the lock member 17 is attached to the upper rail 5 maintains the state in which the lock teeth 25 are fitted in the lock notches 27.　In this state, when an operation handle 33 is operated upward, the rear end part 23a of the lock member 17 is biased downward through a release lever 31 to release lock.　The operation handle 33 is inserted into the upper rail 5 from the front side and disposed to operate with the release lever 31 in a coupled manner.

　　　　As illustrated in FIGS. 3 and 7, the lock member 17 includes protruding portions 19b as support receiving portions protruding toward sides from right and left sides at a position corresponding to the fixation hole 19a of the fixation portion 19.　The protruding portions 19b protrude toward sides at thicknesses same as the plate thickness of the lock member 17 including the fixation portion 19, and have rectangular shapes in plan view.　As illustrated in FIG. 2, the lock member 17 includes a front-side first tilted portion 35 on the front side, which is a side of the fixation portion 19 opposite to the rear-side tilted part 21.　The front-side first tilted portion 35 is tilted lower further on the front side.

　　　　An operation-handle receiving portion 37 extends substantially in parallel to the fixation portion 19 from a front end (lower end) of the front-side first tilted portion 35 toward the front side.　A front-side second tilted portion 39 extends obliquely downward from a front end of the operation-handle receiving portion 37 toward the front side.　Leading end parts 67a of arm portions 67 of the operation handle 33, which are to be described later, are each placed in contact with an upper surface of the operation-handle receiving portion 37.　A front-side elastic deformation portion 41 extends substantially in parallel to the operation-handle receiving portion 37 from a front end of the front-side second tilted portion 39 toward the front side.

　　　　A moderately tilted portion 43 bent and extending slightly upward obliquely toward the front side is provided at a front end of the front-side elastic deformation portion 41.　Front-end click portions 45 protruding toward right and left sides are provided at a front end part of the moderately tilted portion 43.　The front-end click portions 45 are engaged from below with a concave stepped part 33a provided on a lower surface of the operation handle 33.　The front-side elastic deformation portion 41 presses the stepped part 33a upward through the front-end click portions 45.　Pressing force applied on the stepped part 33a by the front-side elastic deformation portion 41 is set weaker than pressing force applied on the lock notches 27 by the lock teeth 25 of the rear-side elastic deformation part 23.　This configuration keeps a lower part of a leading end of the operation handle 33 in contact with the operation-handle receiving portion 37 of the lock member 17.

　　　　As illustrated in FIG. 2, the front side of a substantially central part of the front-side elastic deformation portion 41 in the front-rear direction protrudes out of the upper rail 5 toward the front side when the lock member 17 is attached to the upper rail 5.

　　　　As illustrated in FIG. 8, the release lever 31 includes right and left sidewalls 47, and an upper wall 49 connecting upper ends of the right and left sidewalls 47 in rear-side substantially half regions of the right and left sidewalls 47.　Except for the vicinities of front and rear parts, the lock member 17 is disposed between the right and left sidewalls 47 of the release lever 31.　In other words, the release lever 31 is provided overlapping with the lock member 17 in longitudinal and vertical directions of the upper rail 5.

　　　　Recessed parts 47a as support portions are provided at upper end parts of the sidewalls 47 on the front side of the upper wall 49 of the release lever 31.　The recessed parts 47a are shaped in curved recess arcs.　As illustrated in FIG. 10, the recessed parts 47a are disposed below the right and left protruding portions 19b of the lock member 17, and engaged with lower parts of the protruding portions 19b.　The protruding portions 19b of the lock member 17 and the recessed parts 47a of the release lever 31 serve as a swing pivot portion 51 when front and rear parts of the release lever 31 vertically swing.　The swing pivot portion 51 coincides with a fixation site of the lock member 17 to the upper rail 5 by the fixing member 15 in the front-rear direction.

　　　　The release lever 31 includes a release pressing portion 53 at an end part on the rear side of the swing pivot portion 51.　Lower ends 47b of the sidewalls 47 extending downward from right and left ends of the upper wall 49 of the release pressing portion 53 contact an upper surface of the rear end part 23a of the rear-side elastic deformation part 23 in the lock member 17.

　　　　Front-part sidewalls 55 bent closer to each other are provided at front end parts of the right and left sidewalls 47 of the release lever 31, and have upper ends connected by a front-part upper wall 57.　The front-part sidewalls 55 serve as acting portions (actuation portions 59) to which force of rotational operation of the operation handle 33 upward in the lock release direction is applied from below.　In other words, the release lever 31 includes the acting portion (actuation portions 59) to which the force of operation of the operation handle 33 is applied, on the front side opposite to the release pressing portion 53 on the rear side of the swing pivot portion 51.　The actuation portions 59 are composed of the front-part sidewalls 55 and latch protrusions 61 and first convex portions 47c as pressed-in portions to be described later.　The actuation portions 59 of the release lever 31 are positioned on the front side opposite to the release pressing portion 53 on the rear side of the swing pivot portion 51.

　　　　As illustrated in FIGS. 8 and 9, the latch protrusions 61 are provided at front ends (near the acting portions) of the right and left front-part sidewalls 55.　The latch protrusions 61 are bent substantially at right angle from front ends of the front-part sidewalls 55 toward the upper sidewalls 5b, and protrude outward in the width direction from the front-part sidewalls 55.　Drooping portions 63 extending downward from the latch protrusions 61 and bent portions 65 extending inward from lower ends of the drooping portions 63 are provided at positions inside of leading ends of the latch protrusions 61.　The latch protrusions 61, the drooping portions 63, and the bent portions 65 are provided in an identical plane in a direction orthogonal to the front-rear direction, and collectively referred to bent flanges 66.

　　　　The inside of the bent flanges 66 serves as an opening 80 into which the operation handle 33 is inserted from the front side.　In other words, the bent flanges 66 are opening peripheries that are the periphery of the opening 80.　The right and left bent portions 65 serve as a lower surface part to be contacted by the operation handle 33 from above when the operation handle 33 is pressed downward.　A slit 81 is provided between the right and left bent portions 65.

　　　　The front-side elastic deformation portion 41 is positioned between the right and left drooping portions 63 illustrated in FIG. 9 in a free state (state in which the operation handle is not assembled) of the lock member 17.　An interval H between leading ends of the right and left bent portions 65 is larger than the width of the front-side elastic deformation portion 41 in a right-left direction (the right-left direction in FIG. 9 or a direction orthogonal to the sheet of FIG. 2).　With this configuration, the front-side elastic deformation portion 41 can be placed between the drooping portions 63 from below through the slit 81 between the right and left bent portions 65.

　　　　The operation handle 33 has a substantially U shape including the pair of right and left arm portions 67 at both ends corresponding to the pair of right and left rail bodies 6 illustrated in FIG. 1.　The pair of right and left arm portions 67 extend in the front-rear direction and are inserted in the right and left upper rails 5 through front ends thereof.　The right and left arm portions 67 are connected and integrated with each other through a grasping portion (not illustrated) extending in the vehicle width direction.　The grasping portion is grasped by a passenger operating the operation handle 33.

　　　　As illustrated in FIGS. 2 and 10, a rear end part of each arm portion 67 is inserted between the right and left sidewalls 47 of the release lever 31, and as described above, the leading end part 67a on the rear side contacts the upper surface of the operation-handle receiving portion 37 of the lock member 17 as illustrated in FIG. 2.　The arm portions 67 including the above-described grasping portion (not illustrated) are entirely made of a cylinder member, and parts on the rear side of the vicinity of the stepped part 33a serve as operation portions 69 having sections in substantially hat shapes obtained by vertically squeezing the cylinder member as illustrated in FIG. 11.

　　　　Each operation portion 69 includes an upper surface 69a, side surfaces 69b extending downward from right and left end parts of the upper surface 69a, and flanges 69c extending substantially in parallel to the upper surface 69a from lower ends of the right and left side surfaces 69b toward right and left sides.　The operation portion 69 also has an opening at a lower part of the hat shape.　The lower part of the hat shape serves as a housing recess 70 in which the front-side elastic deformation portion 41 of the lock member 17 is housed.　The flanges 69c substantially contact lower ends 55a of the front-part sidewalls 55 of the release lever 31.　In this state, force of upward operation of the operation handle 33 is applied to the lower ends 55a of the front-part sidewalls 55 from below through the flanges 69c.

　　　　As illustrated in FIG. 3, the release lever 31 includes the first convex portions 47c at positions facing to each other on the rear side of leading ends of the flanges 69c of the operation portions 69.　The first convex portions 47c protrude inward from the sidewalls 47 of the release lever 31, and are slightly separated from the flanges 69c in an assembled state of the operation handle 33 in which the front-end click portions 45 are engaged with the stepped part 33a.　Second convex portions 47d protruding inward from the sidewalls 47 are provided at upper parts of the sidewalls 47 on the front side of the first convex portions 47c.　In a hold state in which the operation handle 33 is not operated, the second convex portions 47d are provided above the flanges 69c and separated from the flanges 69c.

　　　　As illustrated in FIG. 10, the bent portions 65 of the bent flanges 66 are positioned below the flanges 69c at a front end of the release lever 31.　When the grasping portion of the operation handle 33 is pressed downward, the operation handle 33 swings in the anticlockwise direction in FIG. 2 with the bent portions 65 as pivots while elastically deforming the front-side elastic deformation portion 41.　Simultaneously, as illustrated in FIG. 12, the leading end parts 67a are displaced upward from the position illustrated with a solid line to the position illustrated with a dashed and double-dotted line, and the flanges 69c contact the second convex portions 47d from below.　This restricts excess downward movement of the operation portions of the operation handle 33.　In addition, a front part of the release lever 31 does not move downward because the latch protrusions 61 are engaged with latch protrusion housing spaces 71 (FIG. 13) of the upper sidewalls 5b of the upper rail 5, which is described later.

　　　　The latch protrusion housing spaces 71 in which the latch protrusions 61 of the release lever 31 are housed are provided at a front end of the upper rail 5.　The latch protrusion housing spaces 71 are provided by recesses 73 substantially L-shaped toward the rear side and provided at front ends of the pair of right and left upper sidewalls 5b of the upper rail 5.　As illustrated in FIG. 13 in an enlarged manner, each recess 73 includes a bottom part 73a at a rear end.　A lower-side part 73b extends toward the front side from a lower end of the bottom part 73a with a front end reaching at the front end of the upper rail 5.

　　　　An upper first side part 73c extends toward the front side from an upper end of the bottom part 73a, and has a length shorter than that of the lower-side part 73b in the front-rear direction.　In other words, a front end of the upper first side part 73c does not reach at the front end of the upper rail 5.　A front-side bottom part 73d extends upward from the front end of the upper first side part 73c, and an upper second side part 73e extends toward the front side from an upper end of the front-side bottom part 73d.

　　　　In a state in which the release lever 31 is assembled with the upper rail 5 as illustrated in FIGS. 2 and 3, each latch protrusion 61 is positioned closer to the lower-side part 73b between the lower-side part 73b and the upper second side part 73e.　A space between the lower-side part 73b and the upper second side part 73e is positioned on the front side inside the recess 73 and serves as a front-side recess 73f (lower movement restriction portion) that allows vertical motion of the latch protrusion 61 when the release lever 31 is operated to vertically swing.　The lower-side part 73b of each recess 73 restricts downward movement of the front part of the release lever 31.

　　　　A space on the rear side of the front-side recess 73f inside each recess 73, in other words, a space between the lower-side part 73b and the upper first side part 73c serves as a rear-side recess 73r (lock release restriction portion) that restricts movement of the release lever 31 in the lock release direction when the release lever 31 is moved to the rear side.

　　　　In a hold state illustrated in FIG. 2 in which the operation handle 33 is not operated, lower ends of the latch protrusions 61 of the release lever 31 are positioned closer to the lower-side parts 73b in the recesses 73 of the upper rail 5.　Thus, in the release lever 31 in this state, the protruding portions 19b and the recessed parts 47a of the swing pivot portion 51 are substantially in contact with each other, which restricts downward movement of the front-part sidewalls 55 of the release lever 31 (the actuation portions 59).

　　　　The following describes operation of the seat slide device 1 configured as described above.

　　　　FIGS. 1 to 3 illustrate a lock held state in which the lock teeth 25 of the lock member 17 are engaged and locked with the lock notches 27 of the lower rail 3.　In this state, when a passenger operates the operation handle 33 upward, the operation handle 33 swings upward with the leading end parts 67a as pivots since a lower surface of the leading end part 67a of each arm portion 67 is supported by the operation-handle receiving portion 37 of the lock member 17.　When the operation handle 33 is swung upward, the flanges 69c of the operation portions 69 press upward the lower ends 55a of the front-part sidewalls 55 of the release lever 31 as actuation surfaces.

　　　　Accordingly, the release lever 31 swings about the swing pivot portion 51 in the clockwise direction in FIG. 2.　Each latch protrusion 61 of the release lever 31 moves upward toward the upper second side part 73e inside of the front-side recess 73f illustrated in FIG. 13.　With the swing of the release lever 31, the lower ends 47b of the release pressing portion 53 on the rear side presses downward the rear end part 23a corresponding to a part around the lock portions of the lock member 17, and the rear-side elastic deformation part 23 elastically deforms downward.　As a result, the lock teeth 25 come off the lock notches 27 of the lower rail 3, and lock is released.　When lock is released, a seat (not illustrated) together with the upper rail 5 can be moved toward the front and rear sides relative to a floor surface of the vehicle on which the lower rail 3 is provided to a seat position desired by the passenger.

　　　　When the seat position is determined and the passenger releases the operation handle 33, the rear-side elastic deformation part 23 of the lock member 17 presses the lower ends 47b of the release pressing portion 53 upward and swings the release lever 31 back to the lock held state illustrated in FIG. 2.　In this case, the release lever 31 swings about the swing pivot portion 51 in the anticlockwise direction in FIG. 2, and each latch protrude 61 moves downward inside the front-side recess 73f illustrated in FIG. 13 toward the lower-side part 73b.

　　　　In the state illustrated in FIG. 2, it is assumed that, for example, the vehicle is hit from the rear side and a heel of the passenger collides with the operation handle 33 toward the rear side.　In this case, with impact acting on the operation handle 33, the front-end click portions 45 come off the stepped part 33a, and the operation handle 33 moves toward the rear side.　A load received by the operation handle 33 acts on the first convex portions 47c of the release lever 31 illustrated in FIGS. 2 and 3 through rear ends of the flanges 69c illustrated in FIG. 11.　Upon reception of the load by the first convex portions 47c toward the rear side, the recessed parts 47a of the release lever 31 at the swing pivot portion 51 come off the protruding portions 19b of the lock member 17 and move toward the rear side.　This reduces impact of the collision of the heel of the passenger with the operation handle 33.　When the operation handle 33 moves to the rear side, a rear end of the upper surface 69a of each operation portion 69 illustrated in FIG. 11 contacts the front-side first tilted portion 35 of the lock member 17 illustrated in FIG. 2 and is prohibited from further moving toward the rear side.　The leading end parts 67a of the operation handle 33 can more largely move toward the rear side than the release lever 31, moving upward toward the rear side along the front-side first tilted portion 35.　When the leading end parts 67a move upward, the flanges 69c come off positions facing to the first convex portions 47c, and thus the release lever 31 does not move toward the rear side more than needed.

　　　　When the release lever 31 moves toward the rear side, each latch protrusion 61 illustrated in FIG. 13 moves inside the corresponding recess 73 from the front-side recess 73f to the rear-side recess 73r.　When positioned at the rear-side recess 73r, the latch protrusion 61 is prohibited from moving in the vertical direction between the upper first side part 73c and the lower-side part 73b.　In other words, the rear-side recess 73r in the vertical direction has an interval set substantially equal to or slightly larger than the height of the latch protrusions 61 in the vertical direction.　In this case, at least a gap needs to be provided between an upper end of the latch protrusion 61 and a lower end of the upper first side part 73c when the release lever 31 is moved to the rear side.

　　　　In this manner, the release lever 31 is prohibited from vertically swinging at a retracted position where the release lever 31 is moved to the rear side.　Thus, the release lever does not rotate in the lock release direction when the operation handle 33 moves in the lock release direction, which eliminates the risk of downward pressing of the rear end part 23a of the rear-side elastic deformation part 23 of the lock member 17 by the release pressing portion 53 on the rear side, thereby preventing lock release.　Accordingly, no load acts on the release lever 31 and the lock member 17 in the lock release direction when the heel of the passenger collides with the operation handle 33 toward the rear side, thereby preventing unexpected movement of a seat on which the passenger is seated.

　　　　When a load acts upward on part of the release lever 31 on the front side of the swing pivot portion 51 in the retracted position where the release lever 31 is moved to the rear side, each latch protrusion 61 of the release lever 31 contacts the upper first side part 73c in the rear-side recess 73r and is prohibited from moving upward.　In this manner, the upper first side part 73c serves as a lock release restriction portion that prohibits the release lever 31 from moving in the lock release direction when the release lever 31 is moved to the rear side.

　　　　As illustrated in FIG. 10, the lock member 17 and the release lever 31 can be assembled with each other before assembled with the upper rail 5.　Since the release lever 31 has a lower part opened entirely in the longitudinal direction, the lock member 17 is inserted between the right and left sidewalls 47 through the opening of the lower part while being tilted.　When inserted to a position where the fixation portion 19 including the protruding portions 19b is higher than the sidewalls 47, the lock member 17 is set back to a horizontal orientation, and thereafter moved downward to allow the protruding portions 19b of the lock member 17 to enter into the recessed parts 47a of the release lever 31.

　　　　In this state, the lower ends 47b of the release lever 31 contact on the rear end part 23a of the lock member 17, and the front side of the vicinity of a central position on the front-side elastic deformation portion 41 in the front-rear direction protrudes toward the front side from the release lever 31.　As illustrated in FIGS. 1 to 3, the lock member 17 and the release lever 31 thus assembled are placed between the right and left upper sidewalls 5b of the upper rail 5, and the fixation portion 19 of the lock member 17 is fixed to the upper-rail top wall 5a of the upper rail 5 by the fixing member 15.　In this manner, the lock member 17 and the release lever 31 can be assembled with the upper rail 5 only by the fixing member 15 after assembled with each other in advance, thereby improving assembly performance.

　　　　When the lock member 17 and the release lever 31 are assembled with the upper rail 5, each operation portion 69 of the operation handle 33 is inserted through a front-end opening (the opening 80 in FIG. 9) of the release lever 31 while the front-side elastic deformation portion 41 of the lock member 17 is bent downward.　When becoming bent downward, the front-side elastic deformation portion 41 moves the slit 81 between the right and left bent portions 65 illustrated in FIG. 9.

　　　　The operation handle 33 is inserted into the release lever 131 while the housing recess 70 is moved along the front-side elastic deformation portion 41.　Then, as illustrated in FIGS. 2 and 10, each leading end part 67a reaches at an operation-handle receiving portion 37 through the front-side second tilted portion 39, and the front-end click portions 45 of the lock member 17 are inserted to a position corresponding to the stepped part 33a.　As a result, the front-end click portions 45 are engaged with the stepped part 33a, which completes the assembly.　As described above, the operation handle 33 only needs to be inserted into the release lever 31 while the front-side elastic deformation portion 41 of the lock member 17 is bent downward, thereby improving assembly performance for the operation handle 33.

　　　　The right and left sidewalls 47 of the release lever 31 are disposed along the right and left upper sidewalls 5b of the upper rail 5, and the release pressing portion 53, the recessed parts 47a (swing pivot portion 51), and the actuation portions 59 are substantially linearly arranged in the front-rear direction.　With this configuration, the release lever 31 can have a reduced height in the vertical direction, and thus can be efficiently disposed in a narrow space inside the upper rail 5, thereby achieving downsizing of the entire device.

　　　　The lock member 17 according to the present embodiment includes: the fixation portion 19 as a base part including the swing pivot portion 51 and fixed to the upper rail 5; the rear-side elastic deformation part 23 as a rear-side biasing part positioned on the rear side of the fixation portion 19 and configured to bias the lock teeth 25 in the lock direction; and the front-side elastic deformation portion 41 as a front-side biasing part positioned on the front side of the fixation portion 19, configured to bias the release lever 31 and the operation handle 33 upward, and set to exert biasing force weaker than that of the rear-side elastic deformation part 23.

　　　　With this configuration, in the present embodiment, a biasing member (the rear-side elastic deformation part 23) that biases the lock member 17 in the lock direction, and a biasing member (the front-side elastic deformation portion 41) that biases the operation handle 33 upward are achieved by an integrated spring member.　Accordingly, the number of components can be reduced as compared to a configuration in which these two biasing members are separately provided.

　　　　The release pressing portion 53 of the release lever 31 on the rear side is biased upward by the rear-side elastic deformation part 23 of the lock member 17.　Simultaneously, as illustrated in FIG. 10, the flanges 69c of the operation handle 33 contact the lower ends 55a of the front-part sidewalls 55 of the release lever 31 from below.　Accordingly, the front-part sidewalls 55 of the release lever 31 are biased upward through the operation handle 33 (flanges 69c), the stepped part 33a of which is biased upward by the front-side elastic deformation portion 41.

　　　　As described above, in the lock member 17, the rear-side elastic deformation part 23 having an upward biasing function is provided on the rear side, and the front-side elastic deformation portion 41 having an upward biasing function is provided on the front side.　With this configuration, the release lever 31 is swingably supported by the lock member 17 through the swing pivot portion 51 at a substantially central part in the front-rear direction.　In this manner, the two components of the lock member 17 and the release lever 31 can be assembled with each other as a unit before attached to the upper rail 5, thereby improving assembly performance.

　　　　When operated upward, the operation handle 33 swings as the leading end part 67a of each arm portion 67 presses the operation-handle receiving portion 37 of the lock member 17 downward.　Since the lock member 17 includes a handle support portion (the operation-handle receiving portion 37) when the operation handle 33 is operated to swing, there is no need to redundantly provide a handle support portion to the upper rail, which leads to reduction of the number of components and reduction of the height of the upper rail.

　　　　In the lock member 17 according to the present embodiment, the fixation portion 19, the operation-handle receiving portion 37 as a handle support portion, and the front-side elastic deformation portion 41 are connected with each other in a stepped manner when viewed from side, and extend substantially in parallel to each other in the front-rear direction.　Each operation portion 69 of the operation handle 33, as a rear-side connection portion, has a section in a substantially inverted U shape, and the operation-handle receiving portion 37 of the lock member 17 is housed in the housing recess 70 of the operation portion 69, having a section in an inverted U shape, from below.

　　　　Thus, the lock member 17 can be formed by bending a plate spring member having a flat plate shape, and have a simplified structure, which facilitates manufacturing.　Since the operation-handle receiving portion 37 of the lock member 17 is housed in the housing recess 70, which has a section in an inverted U shape, of each operation portion 69 of the operation handle 33, a reduced height in the vertical direction can be obtained where the operation handle 33 and the operation-handle receiving portion 37 of the lock member 17 overlap with each other.

　　　　In the present embodiment, the front end of the front-side elastic deformation portion 41 of the lock member 17 is provided with the front-end click portions 45 as fitting protrusions protruding toward right and left sides at a position on the front side of the actuation portions 59 of the release lever 31.　The stepped part 33a as a fitting recess to which the front-end click portioned 45 of the front-side elastic deformation portion 41 are fitted is formed at a lower part of the operation handle 33.　The front-side elastic deformation portion 41 of the lock member 17 is housed in the housing recess 70 of the operation handle 33, which extends in the front-rear direction.

　　　　With this configuration, since the front-end click portions 45 of the front-side elastic deformation portion 41 are fitted to the stepped part 33a of the operation handle 33 at a position on the front side of the actuation portions 59 of the release lever 31, the operation handle 33 can be prohibited from moving in the axial direction (front-rear direction).　This prevents force of the operation handle 33 in the axial direction from directly acting the release lever 31, thereby prohibiting the release lever 31 from moving in the axial direction.　When the operation handle 33 receives upward biasing force by the front-side elastic deformation portion 41, a leading end of each operation portion 69 is biased downward with the front-part sidewalls 55 of the release lever 31 as pivots.　In this case, the front-part sidewalls 55 of the release lever 31 are biased upward by the flanges 69c of the operation handle 33.　Accordingly, in the release lever 31, the recessed parts 47a and the protruding portions 19b of the swing pivot portion 51 are maintained being engaged with each other, and the leading end of the operation portion 69 of the operation handle 33 is maintained being pressed against the operation-handle receiving portion 37.

　　　　The front-side elastic deformation portion 41 of the lock member 17 is housed in the housing recess 70 of the operation handle 33.　With this configuration, when the operation handle 33 is operated upward, the front-side elastic deformation portion 41 biasing the operation handle 33 upward is moved with the operation handle 33.　In this manner, a reduced height in the vertical direction can be obtained where the operation handle 33 and the front-side elastic deformation portion 41 overlap with each other in the front-rear direction.

　　　　In the present embodiment, the fitting protrusion of the front-side elastic deformation portion 41 of the lock member 17 is positioned on the front side of the front end of the upper rail 5.　With this configuration, when the operation handle 33 is assembled, the front-side elastic deformation portion 41 protruding on the front side can be easily moved downward, and in this state, the operation handle 33 can be easily inserted into the release lever 31.　An interval H between end parts of the right and left front-end click portions 45 is smaller than the width of each operation portion 69 of the operation handle 33 in the right and left direction.　Thus, the front-end click portions 45 are hidden by the operation handle 33 and difficult to see from above once the operation handle 33 is assembled, thereby improving appearance.　In addition, the front-end click portions 45 can be prevented from coming off the stepped part 33a being unexpectedly hit by an object.

　　　　In the present embodiment, each actuation portion 59 of the release lever 31 includes the latch protrusion 61 that is positioned in the front-side recess 73f (lower movement restriction portion) provided to the upper rail 5 to allow the actuation portion 59 to rotate in the lock release direction and is engaged with the lower-side part 73b to restrict downward movement of the release lever 31.　With this configuration, when the operation handle 33 is pressed downward, the actuation portion 59 of each latch protrusion 61 of the release lever 31 is prohibited from moving downward, thereby maintaining engagement of the recessed parts 47a and the protruding portions 19b as the swing pivot portion 51 of the release lever 31.

　　　　As illustrated in FIG. 9, the front end of the release lever 31 is provided with the opening 80, to which the corresponding operation portion 69 of the operation handle 33 is inserted, and the bent flanges 66 serving as opening peripheries that are the periphery of the opening 80 include the slit 81, into which the front-side elastic deformation portion 41 of the lock member 17 is placed from below, at lower parts.　To assemble the operation handle 33, the front-side elastic deformation portion 41 is pressed downward through the slit 81.　Then, while the front-side elastic deformation portion 41 is pressed down, the operation handle 33 can be easily inserted into the release lever 31 through the opening 80.

　　　　In the present embodiment, in each operation portion 69 of the operation handle 33, the flanges 69c protruding toward right and left sides at lower ends are provided in the front-rear direction, the front-part sidewalls 55 of the release lever 31 are positioned on upper surfaces of the flanges 69c, and the bent portions 65 as lower surface parts that the flanges 69c contact from above are provided below the bent flanges 66.　The second convex portions 47d are provided protruding inward from the sidewalls 47 of the release lever 31.　The upper surfaces of the flanges 69c contact the second convex portions 47d from below when a load is applied downward on the operation handle 33 so that part of the operation handle 33 on the front side of the bent portions 65 is displaced downward with the bent portions 65 as pivots whereas part of the operation handle 33 on the rear side of the bent portions 65 is displaced upward.

　　　　When a downward load is received by the grasping portion on the front side, the operation handle 33 swings in the anticlockwise direction in FIG. 2 with the bent portions 65 as pivots while the front-side elastic deformation portion 41 is bent.　In this case, the upper surface 69a of each operation portion 69 (the leading end part 67a of the arm portion 67) is moved upward and separated from the operation-handle receiving portion 37 of the lock member 17, and leading ends of the flanges 69c are shifted from the first convex portions 47c in the vertical direction.

　　　　Accordingly, when the operation handle 33 is pressed downward and the operation handle 33 receives a load toward the rear side, any effect of this load on the release lever 31 can be avoided to prevent the release lever 31 from moving toward the rear side.　When the upper surface 69a of each operation portion 69 (the leading end part 67a of the arm portion 67) is moved upward and separated from the operation-handle receiving portion 37 of the lock member 17, the flanges 69c contact the second convex portions 47d from below, thereby preventing excess swing of the operation handle 33.　Such an effect of preventing excess swing of the operation handle 33 is achieved when the upper rail 5 protrudes on the front side of the lower rail 3.

　　　　In the present embodiment, the latch protrusion housing spaces 71 is provided to the upper rail 5, and the latch protrusions 61 is provided to the release lever 31.　This configuration can prevent, without any redundantly provided component, lock release when the release lever 31 is moved toward the rear side.　The bent flanges 66 including the latch protrusions 61 are bent to protrude outward, and thus can avoid interfering with assembly of the lock member 17 with the release lever 31.　When the release lever 31 and the lock member 17 being assembled with each other are assembled with the upper rail 5, the bent flanges 66 including the latch protrusions 61 only need to be placed into the recesses 73 from the front end of the upper rail 5, which facilitates the assembly.

　　　　In addition, the swing pivot portion 51 can be set substantially in the thickness of the lock member 17 as a plate spring, thereby achieving a smaller swing pivot structure.

　　　　When the release lever 31 receives impact and is moved toward the rear side, the recessed parts 47a come off the protruding portions 19b.　In this case, the release lever 31 is moved downward only by the height of part of the protruding portions 19b being placed in the recessed parts 47a, and thus the amount of the downward movement is extremely small.　Accordingly, the amount of downward pressing of the lock member 17 by the release lever 31 when the recessed parts 47a come off the protruding portions 19b is also extremely small, thereby more reliably preventing lock release.

　　　　A load at which the recessed parts 47a come off the protruding portions 19b can be easily set by changing the shape of the recessed parts 47a or the shape of the protruding portions 19b.　For example, the lower parts of the protruding portions 19b may have curved surface shapes that are convex downward in accordance with the curved surface shapes of the recessed parts 47a.　The recessed parts 47a may each have a plane bottom part and tilted surfaces on the front and rear sides of the plane bottom part.

　　　　The embodiments of the present invention are described above but are merely examples for facilitating understanding of the present invention.　Thus, the present invention is not limited by the embodiments.　The technical scope of the present invention is not limited to the specific technological matters disclosed in the above-described embodiments, but includes various modifications, changes, alternative technologies that can be easily derived from the disclosure.

　　　　The entire contents of Japanese Patent Application No. 2016-193044, filed on September 30, 2016, and Japanese Patent Application No. 2017-155197, filed on August 10, 2017, are herein incorporated by reference.

Claims

　　　　A seat slide device comprising:
　　　　a lower rail extending in a vehicle front-rear direction;
　　　　an upper rail configured to move relative to the lower rail in a longitudinal direction of the lower rail;
　　　　a lock member attached to the upper rail and including a lock portion biased in a lock direction in which the lock portion comes into engagement with a lock receiving portion provided to the lower rail;
　　　　a release lever including a release pressing portion provided at a position of overlapping with the lock member in a longitudinal direction of the upper rail and capable of pressing a part of the lock member around the lock portion to release engagement of the lock portion with the lock receiving portion, an actuation portion actuated by a lock release operation of an operation handle, and a swing pivot portion provided between the release pressing portion and the actuation portion; and
　　　　the operation handle disposed below the actuation portion of the release lever and supported on a front side of the swing pivot portion of the release lever so as to be rotatable relative to the upper rail and configured to actuate the actuation portion of the release lever,
　　　　wherein the lock member is a plate spring integrally including:
　　　　a base part including the swing pivot portion and fixed to the upper rail;
　　　　a rear-side biasing part positioned on a rear side of the base part and configured to bias the lock portion in the lock direction; and
　　　　a front-side biasing part positioned on the front side of the base part and configured to bias the operation handle upward and set to have biasing force weaker than biasing force of the rear-side biasing part.
　　　　The seat slide device according to claim 1, wherein, at the swing pivot portion, a pair of protruding portions from right and left end parts of the base part are rotatably engaged with a pair of recessed parts provided at upper end parts of sidewalls of the release lever, and the engagement is maintained by biasing force of the plate spring.
　　　　The seat slide device according to claim 1 or 2, further comprising a fixing member that fixes the base part of the lock member to a lower surface of the upper rail, wherein
　　　　the fixing member includes a protrusion provided on a side of the lock member opposite to the upper rail, the protrusion protruding toward sides, and
　　　　the release lever includes lock protrusions positioned above the protrusion.
　　　　The seat slide device according to any one of claims 1 to 3, wherein the lock member includes a handle support portion that supports the operation handle by allowing a rear end of a rear-side connection portion of the operation handle to contact the handle support portion from above when the operation handle is operated upward and the actuation portion of the release lever is moved upward.
　　　　The seat slide device according to claim 4, wherein
　　　　in a side view of the lock member, the base part, the handle support portion, and the front-side biasing part are connected with each other in a stepped manner, and extend in the front-rear direction,
　　　　the rear-side connection portion of the operation handle has a section in an inverted U shape, and
　　　　the handle support portion of the lock member is housed from below in a housing recess of the rear-side connection portion, which has a section in the inverted U shape.
　　　　The seat slide device according to claim 5, wherein
　　　　a front end of the front-side biasing part of the lock member is provided with a fitting protrusion toward right and left sides or upward at a position on the front side of the actuation portion of the release lever,
　　　　a fitting recess to which the fitting protrusion of the front-side biasing part is fitted is provided at a lower part of the operation handle, and
　　　　the front-side biasing part of the lock member is housed in the housing recess extending in a front-rear direction of the operation handle.
　　　　The seat slide device according to claim 6, wherein
　　　　the fitting protrusion of the front-side biasing part is positioned on the front side of a front end of the upper rail, and
　　　　an interval between end parts of the fitting protrusion is smaller than a width of the operation handle in a right-left direction.
　　　　The seat slide device according to any one of claims 1 to 7, wherein
　　　　the actuation portion of the release lever includes a latch protrusion that is positioned at a lower movement restriction portion provided to the upper rail and allows rotation of the release lever in a lock release direction but restricts downward movement of the release lever,
　　　　a front end of the release lever is provided with an opening into which a rear-side connection portion of the operation handle is inserted, and
　　　　an opening surrounding edge forming a periphery of the opening includes a slit at a lower part thereof, the slit allowing the front-side biasing part of the lock member to be inserted in the opening from below.
　　　　The seat slide device according to claim 8, wherein
　　　　the rear-side connection portion of the operation handle includes a flange provided at a lower end thereof to extend in the front-rear direction while protruding toward right and left sides,
　　　　the actuation portion of the release lever actuated by a lock release operation of the operation handle is positioned on an upper surface of the flange, and the lower part of the opening surrounding edge includes a lower surface part that the flange contacts from above, and
　　　　a second convex portion is formed to protrude inward from a sidewall of the release lever, the upper surface of the flange contacting the second convex portion from below when a downward load is applied on the operation handle and a part on the front side of the lower surface part is displaced downward with the lower surface part as a pivot whereas a part on the rear side of the lower surface part is displaced upward.