Seat slide apparatus for vehicle

A seat slide apparatus for a vehicle includes an upper rail configured to support a seat at an upper portion of the upper rail, a lower rail supporting the upper rail in a manner that the upper rail and the lower rail are movable relative to each other, and a shaft member extended in a lengthwise direction of the upper rail, wherein the upper rail includes a pair of vertical wall portions extended in an upper/lower direction, the upper rail includes a bent portion connecting the vertical wall portions to each other and the shaft member is provided at an inner side of the bent portion, and the shaft member includes a threaded portion provided at each end thereof in an axial direction, the bent portion includes lengthwise-direction-end portions, and the threaded portions of the shaft member face the lengthwise-direction-end portions of the bent portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2013-114698, filed on May 30, 2013, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to a seat slide apparatus for a vehicle.

BACKGROUND DISCUSSION

Usually, a seat slide apparatus for a vehicle includes an upper rail supporting a seat at an upper portion thereof and a lower rail supporting the upper rail in a state where the upper rail and the lower rail are movable relative to each other. In many cases, the upper rail is made from plate material which is bent or folded.

For example, according to a seat slide apparatus described in JP2004-90765A (which will be hereinafter referred to as Patent reference 1), an upper rail includes a pair of vertical wall portions facing each other and a bent portion connecting upper portions of the vertical wall portions to each other. A threaded portion used for fastening a seat is provided at each lengthwise-direction-end portion of the upper rail.

Further, JP2003-252087A (which will be hereinafter referred to as Patent reference 2) discloses a configuration where a reinforcement member formed in a plate shape is provided between vertical wall portions which constitute an upper rail. Thus, a support rigidity of the upper rail may be enhanced.

However, for example, at a vehicle collision, an extremely large load which is caused by an external force acting on the seat is applied to the upper rail. In order to avoid a deformation of the upper rail which is caused by such external force, the support rigidity of the upper rail is desired to be even more enhanced. Therefore, room for improvement remains in this regard.

A need thus exists for a seat slide apparatus for a vehicle, which is not susceptible to the drawback mentioned above.

SUMMARY

According to an aspect of this disclosure, a seat slide apparatus for a vehicle includes an upper rail configured to support a seat at an upper portion of the upper rail, a lower rail supporting the upper rail in a manner that the upper rail and the lower rail are movable relative to each other, and a shaft member extended in a lengthwise direction of the upper rail, wherein the upper rail includes a pair of vertical wall portions extended in an upper/lower direction, the upper rail includes a bent portion connecting the vertical wall portions to each other at upper portions of the vertical wall portions and the shaft member is provided at an inner side of the bent portion, and the shaft member includes a threaded portion provided at each end thereof in an axial direction, the bent portion opening in the axial direction of the shaft member includes lengthwise-direction-end portions, and the threaded portions of the shaft member face the lengthwise-direction-end portions of the bent portion.

According to another aspect of this disclosure, a seat apparatus for a vehicle including a seat slide apparatus for a vehicle including an upper rail configured to support a seat at an upper portion of the upper rail, a lower rail supporting the upper rail in a manner that the upper rail and the lower rail are movable relative to each other, and a shaft member extended in a lengthwise direction of the upper rail, wherein the upper rail includes a pair of vertical wall portions extended in an upper/lower direction, the upper rail includes a bent portion connecting the vertical wall portions to each other at upper portions of the vertical wall portions and the shaft member is provided at an inner side of the bent portion, the shaft member includes a threaded portion provided at each end thereof in an axial direction, the bent portion opening in the axial direction of the shaft member includes lengthwise-direction-end portions, and the threaded portions of the shaft member face the lengthwise-direction-end portions of the bent portion, the seat, a support member provided at the upper portion of the upper rail and supporting the seat, and a connection member threadedly attached to each of the threaded portions, and connecting the support member, the upper rail, and the shaft member to each other.

DETAILED DESCRIPTION

An embodiment of a seat slide apparatus for a vehicle related to this disclosure will be explained with reference to the drawings. As illustrated inFIG. 1, a seat1for a vehicle includes a seat cushion2and a seat back3which is provided to be tiltable relative to a rear end portion of the seat cushion2. The seat1is supported at a floor portion F of the vehicle via a seat slide apparatus10.

Specifically, as illustrated inFIGS. 1 and 2, two lower rails11are provided at the floor portion F of the vehicle to extend in a front/rear direction of the vehicle. The lower rails11are arranged to be parallel to each other. An upper rail12is mounted on each of the lower rails11to be movable thereon. A bracket13is fastened to an upper portion of each of the upper rails12.

A second lower rail15extending in a width direction of the vehicle is attached to a front end portion of each of the brackets13so as to span the brackets13across the width direction of the vehicle. Another second lower rail15extending in the width direction of the vehicle is attached to a rear end portion of each of the brackets13so as to span the brackets13across the width direction of the vehicle. A second upper rail16is attached to each of the second lower rails15to be movable on the second lower rail15. In the present embodiment, a seat frame17(a side frame) is fastened to the second upper rails16.

As described above, the seat slide apparatus10of the present embodiment includes first slide rails21and second slide rails22which are arranged in a shape of parallel crosses or a double-cross formation, that is, the first slide rails21and the second slide rails22are arranged to form a substantially rectangular shape. Thus, a seat position in the front/rear direction and the width direction of the vehicle is adjustable. The configurations of the first slide rails21are identical to each other, therefore the description will be made on one of the first slide rails21. The configurations of the second slide rails22are identical to each other, therefore the description will be made on one of the second slide rails22.

The first slide rails21allow a position of the seat1in the vehicle front/rear direction to be adjusted in a case where the upper rails12move on the lower rails11. The second slide rails22allow a position of the seat1in the vehicle width direction to be adjusted in a case where the second upper rails16move on the second lower rails15.

Next, configurations of the lower rails11and the upper rails12which constitute the first slide rails21, and a configuration of a lock mechanism restricting a relative movement of the lower rails11and the upper rails12relative to each other will be described. In the present embodiment, each of the lower rails11and the upper rails12, which constitute the first slide rail21, is formed by performing a folding process on plate material.

Specifically, as illustrated inFIGS. 3 and 4, the lower rail11includes a bottom wall portion23arranged to extend in the vehicle front/rear direction (that is, the direction perpendicular to the paper surface on which each ofFIGS. 3 and 4is drawn). An outer wall portion24is provided in a standing condition at each end of the bottom wall portion23in a width direction thereof (that is, the right and left direction in each ofFIGS. 3 and 4). Further, an upper wall portion25is provided at an upper end of each of the outer wall portions24. Each of the upper wall portions25is formed in a flange shape that is folded back inwardly in the width direction. An inner wall portion26is provided at an end of each of the upper wall portions25to be folded back downwardly. Thus, the inner wall portions26are arranged to face each other in the width direction with a predetermined distance provided therebetween.

On the other hand, the upper rail12includes a pair of vertical wall portions31which are arranged between the inner wall portions26of the lower rail11to extend in an upper/lower direction. The upper/lower direction corresponds to the upper/lower direction of the vehicle in a state where the seat slide apparatus10is mounted on the vehicle. The vertical wall portion31may correspond to a wall portion that is formed to be substantially vertical. The upper rail12includes a bent portion32arranged above the vertical wall portions31for connecting the vertical wall portions31to each other. In addition, the upper rail12includes folded-back portions34each of which is formed by folding a lower end of the corresponding vertical wall portion31upwardly. Thus, each of the folded-back portions34is arranged within a space portion surrounded by the corresponding outer wall portion24, the upper wall portion25and the inner wall portion26of the lower rail11. Plural wheels36are provided at each of the folded-back portions34. The wheels36are in contact with track portions35provided at the bottom wall portion23of the lower rail11for rolling on the track portion35. The track portion35is provided at each end of the bottom wall portion23in the width direction thereof.

That is, the upper rail12of the present embodiment moves on the lower rail11in a manner that the wheels36provided at the folded-back portions34roll, and thus the wheels36run on the track portions35with which the wheels36are in contact. In addition, the upper rail12is restricted from moving relative to the lower rail11in the upper direction and the width direction because the folded-back portions34of the upper rail12are surrounded by the outer wall portions24, the upper wall portions25and the inner wall portions26of the lower rail11. Accordingly, in the present embodiment, a positional relation of the lower rail11and the upper rail12is maintained stably.

As illustrated inFIG. 4, the seat slide apparatus10includes a lock mechanism40for restricting the relative movement of the lower rail11and the upper rail12relative to each other. Specifically, in the present embodiment, plural engagement tabs41are provided at each of the inner wall portions26of the lower rail11to protrude downwardly (refer toFIGS. 1 and 2). In the present embodiment, the engagement tabs41are arranged to be substantially equally spaced from one another to form a comb-teeth configuration. In addition, a lock member43including an engagement portion42is provided between the vertical wall portions31of the upper rail12. A hole portion31bis formed at each of the vertical wall portions31and the engagement portion42is engageable with the corresponding engagement tabs41of the lower rail11via the hole portions31b. Further, according to the lock member43, the engagement portion42moves upwardly and downwardly when an operation handle44provided at a front portion of the seat1is operated (refer toFIGS. 1 and 2). Each of the folded-back portions34includes a cut-out34bwhich allows the engagement portion42to move upwardly and downwardly. Thus, the lock mechanism40of the present embodiment is configured to switch between a locked state where the relative movement between the lower rail11and the upper rail12is restricted and an unlocked state where the relative movement therebetween is allowed.

Specifically, according to the lock mechanism40of the present embodiment, when the operation handle44is not operated, the lock member43is biased by an elastic member and thus the engagement portion42is moved or displaced upwardly. Accordingly, the engagement portion42is engaged with the engagement tabs41of the lower rail11, and thus the relative movement between the lower rail11and the upper rail12is restricted.

In addition, according to the lock mechanism40of the present embodiment, when the operation handle44is lifted upwardly, the lock member43moves downwardly. Accordingly, the engagement between the engagement portion42of the lock mechanism40and the engagement tabs41of the lower rail11is released, and thus the lower rail11and the upper rail12are allowed to move relative to each other.

Next, a support rigidity-enhancing structure of the upper rail12according to the present embodiment will be described.

As illustrated inFIGS. 3 to 6, in the present embodiment, each of the vertical wall portions31constituting the upper rail12includes an upper end portion31a. The upper end portions31aare connected to each other. In the present embodiment, by welding end portions of the upper end portions31ain a lengthwise direction thereof (the right and left direction inFIG. 6, that is, a lengthwise direction of the upper rail12), the upper end portions31aare connected or joined to each other (welded points P1and P2). The bent portion32, which connects the vertical wall portions31, is formed in a bag-shaped configuration including a substantially annular cross-sectional shape (a substantially annular shape of an end surface).

In the present embodiment, a shaft member50formed to extend in the lengthwise direction of the upper rail12is provided at an inner side of the bent portion32. A threaded portion52is provided at each of axial ends of the shaft member50. The threaded portions52face lengthwise-direction-end portions51of the bent portion32opening in the axial direction of the shaft member50. As described above, the bracket13, which supports the seat1(and the second slide rails22) above the upper rail12, is configured to be fastened to the upper rail12with the threaded portions52.

Specifically, in the present embodiment, a pipe53, which corresponds to a hollow pipe, is used for the shaft member50as illustrated inFIGS. 4 and 6. Each of the threaded portions52is formed by threading an internal thread at an inner periphery of the pipe53.

As illustrated inFIGS. 2, 6 and 7, a flange portion54is provided at each lengthwise-direction-end portion of the bracket13to face the corresponding lengthwise-direction-end portion51of the bent portion32in the lengthwise direction of the upper rail12. Further, an insertion hole56, into which a bolt55serving as a fastening member or a connection member is inserted, is provided at each of the flange portions54. Thus, the bracket13is fastened to the upper portion of the upper rail12with a fastening force of the bolts55that are threadedly attached to the threaded portions52of the shaft member50via the insertion holes56.

More specifically, in the present embodiment, as illustrated inFIGS. 3 and 4, lower portions of the bent portion32, which are curved around a lower portion of the shaft member50, serve as receiving portions60that support the lower portion of the shaft member50. A buffer material58which is made of, for example, rubber or soft resin, is interposed between the bent portion32and the shaft member50. As illustrated inFIG. 6, the welded points P1and P2, at which the upper end portions31aof the vertical wall portions31are connected to each other as described above, are set at positions corresponding to the threaded portions52. In the present embodiment, each of the welded points P1and P2serves as a tightened portion61which reduces a diameter of the annular shape of the bent portion32. Thus, the shaft member50is attached to (fitted to) the inner side of the bent portion32by pressure.

An axial length L1of the shaft member50is slightly shorter than a length L2of the bent portion32(that is, the length of the upper rail12) (L1<L2). That is, as illustrated inFIG. 7, the shaft member50of the present embodiment includes an elongation allowance δ for elongation caused by the fastening which is obtained by the threaded portions52. Accordingly, in the present embodiment, positioning of the bracket13is performed easily and the bracket13is fastened to the upper rail12reliably.

Next, an operation of the seat slide apparatus including the above configuration will be described. In the present embodiment, the bracket13for supporting the seat1above the upper rail12is fastened to the upper portion of the upper rail12with use of the threaded portions52provided at the axial ends of the shaft member50. That is, the upper rail12of the present embodiment includes the shaft member50arranged to extend in the lengthwise direction of the upper rail12and serving as a structural body, and supports a seat load. That is, the upper rail12includes the shaft member50as part of the upper rail12. Thus, the support rigidity of the upper rail12is enhanced in the present embodiment.

According to the present embodiment, following effects are obtained.

(1) The upper rail12includes the pair of vertical wall portions31arranged to extend in the upper/lower direction and the bent portion32arranged at the upper portion of each of the vertical wall portions31for connecting the vertical wall portions31to each other. Further, the shaft member50formed to extend in the lengthwise direction of the upper rail12is provided within the bent portion32. The threaded portion52is provided at each of the axial ends of the shaft member50. The threaded portions52, which face the lengthwise-direction-end portions51of the bent portion32opening in the axial direction of the shaft member50, are provided at the axial ends of the shaft member50.

According to the above-described configuration, the bolt55is threadedly attached to, that is, screwed in, each of the threaded portions52of the shaft member50via the lengthwise-direction-end portion51of the bent portion32. Accordingly, the seat1(the bracket13) is fastened to the upper portion of the upper rail12with the fastening force of the bolts55. In addition, the shaft member50serves as the structural body, and thus the support rigidity of the upper rail12is enhanced along an entire length thereof. That is, because the seat load is received by the shaft member50, deformation is not likely to occur to the vertical wall portions31or the bent portion32which are formed by the folding process. Particularly, a bending strength of the upper rail12in the lengthwise direction may be enhanced significantly. Thus, a smooth relative movement between the lower rail11and the upper rail12, and a stable operation of the lock mechanism are assured, thereby ensuring a high reliability. In addition, at the shaft member50, a tensile force which elongates or pulls out the shaft member50is generated by the fastening which is obtained by the threaded portion52provided at each of the axial ends of the shaft member50. Thus, the fastened condition is maintained stably.

(2) The bent portion32of the upper rail12includes the annular shape and the shaft member50is fitted in the inner side of the annular shape. With such a configuration, the shaft member50is maintained at the inner side of the bent portion32easily and reliably with the simple configuration. Thus, the high support rigidity of the upper rail is assured.

(3) The lower portions of the bent portion32, which are curved around the lower portion of the shaft member50so as to surround the lower portion of the shaft member50, form the receiving portions60supporting the lower portion of the shaft member50. With such a configuration, the shaft member50is held at the inner side of the bent portion32against the seat load in a direction in which the shaft member50is pushed downwardly. Thus, the high support rigidity is assured.

(4) The upper rail12includes the tightened portions61(the welded points P1and P2) which connect the upper end portions31aof the vertical wall portions31to each other and thus reduce the diameter of the annular shape of the bent portion32. According to the above-described configuration, after the shaft member50is arranged at the inner side of the bent portion32, the diameter of the annular shape of the bent portion32is reduced so that the shaft member50is attached to the inner side of the bent portion32by pressure (that is, the shaft member50is fitted to the inner side of the bent portion32). Thus, the shaft member50is held at the inside of the bent portion32easily and reliably.

(5) The axial length L1of the shaft member50is slightly shorter than the length L2of the bent portion32(L1<L2). That is, the elongation allowance δ for the elongation of the shaft member50which is caused by the fastening thereof is provided at the shaft member50in advance, and thus the positioning of the upper rail12and the member fastened to the upper rail12is performed easily. Thus, the fastening which uses the threaded portion52is reliably ensured.

(6) The buffer material58is arranged between the bent portion32of the upper rail12and the shaft member50. Thus, a resonance frequency of the seat1is lowered, or resonance amplitude of the seat1is reduced. As a result, a damping effect of the resonance is enhanced. Because the shaft member50that is pre-coated with the buffer material58is used, that is, the shaft member50is coated with the buffer material58in advance, the vibration-proof effects and the sound-proof effects are obtained easily at low costs.

(7) The pipe53, which is hollow, is used as the shaft member50. As a result, weight of the shaft member50is reduced while a high strength is maintained. In addition, because the internal threads are formed at the inner periphery of the axial end portions of the pipe53(the shaft member50), the threaded portions52are provided easily.

The aforementioned embodiment may be modified as follows. In the aforementioned embodiment, the seat1includes the first slide rails21and the second slide rails22which are arranged in the shape of the parallel crosses. The rigidity-enhancing structure of the upper rails12, which is achieved by the shaft member50including the threaded portions52provided at the end portions of the shaft member50, is applied to the first slide rails21. However, the application of the rigidity-enhancing structure is not limited thereto. The similar rigidity-enhancing structure may be applied to the second slide rails22that are provided above the first slide rails21via the brackets13. Alternatively, the similar rigidity-enhancing structure may be applied to the first slide rails21and the second slide rails22.

The second slide rails22may be omitted from the configuration of the present embodiment. That is, the seat frame17(for example, a side frame) may be fastened directly to the shaft member50without interposing a supporting member including, for example, the bracket13.

In the aforementioned embodiment, the bent portion32of the upper rail12includes the bag-shaped configuration of which the cross-sectional shape (the shape of the end surface) is substantially annular. However, the cross-sectional shape of the bent portion32is not limited to the substantially annular. For example, in a case where the shaft member50is formed in a polygon shape, the bent portion32may include such a cross-sectional shape that allows the shaft member50to be fitted into the inner periphery of the bent portion32. In addition, a shape of the opening portion at the lengthwise-direction-end portion51of the bent portion32may be modified arbitrarily.

The bent portion32may include a configuration other than the bag-shaped configuration and may open downwardly. In that case, as illustrated inFIG. 8, an upper rail12B may include vertical wall portions31B. For example, a portion of each of the vertical wall portions31B is cut out and the cut-out portion is bent and raised to form a receiving portion60B which supports the lower portion of the shaft member50arranged at an inner side of a bent portion32B of the upper rail12B. A method of forming the receiving portion60B may be arbitrarily modified. For example, a separate member may be fixedly attached to the vertical wall portions.

In the aforementioned embodiment, the upper rail12is provided with the tightened portions61(the welded portions P1and P2) which connect or join the upper end portions31aof the vertical wall portions31to each other at the end portions of the upper rail12in the lengthwise direction thereof, and thus reduce the diameter of the annular shape of the bent portion32. However, the tightened portion61may be provided at the upper rail12continuously over an entire range in the lengthwise direction of the upper rail12, or at plural positions over the entire range in the lengthwise direction of the upper rail12.

That is, in a case where the tightened portions61are provided at the end portions of the upper rail12in the lengthwise direction thereof, a clearance X is generated between the bent portion32and the shaft member50(and the buffer material58) as illustrated inFIG. 9at an intermediate portion of the upper rail12in the lengthwise direction. However, with the above-described configuration, the clearance X is reduced. As a result, the shaft member50arranged at the inner side of the bent portion32is supported more reliably.

In the aforementioned embodiment, the tightened portion61is formed by connecting the upper end portions31aof the vertical wall portions31to each other by means of welding. However, a method of connecting the upper end portions31aof the vertical wall portions31is not limited to the welding. The upper end portions31aof the vertical wall portions31may be connected to each other by crimping or staking, or by fastening. Alternatively, the upper end portions31amay be connected to each other by adhesion or bonding. A structure of securing the shaft member50at the inner side of the bent portion32B may be arbitrarily modified. For example, the shaft member50may be fixed at the inner side of the bent portion32B by fastening or welding. Alternatively, the shaft member50may be fixed at the inner side of the bent portion32B by adhesion or bonding.

In the aforementioned embodiment, the pipe53, which corresponds to the hollow pipe, is used for the shaft member50. However, the shaft member50is not limited to the hollow pipe but may be a shaft which does not include a hollow portion (that is, the shaft member50may be a so-called solid shaft member). In addition, the apparatus may include a configuration where the buffer material58is not interposed between the bent portion32and the shaft member50.

Further, the threaded portions52provided at the shaft member50in the axial direction thereof are not limited to the internal threads formed at the inner periphery (that is, a nut configuration). The threaded portions52may be formed by external threads provided at an outer periphery of the shaft member50(that is, a bolt configuration). In that case, a length of a portion of the shaft member50at which the external threads are not provided may be defined as “the axial length L1of the shaft member50” and the axial length L1may be set at a smaller value than the length L2of the bent portion32.

As illustrated inFIG. 10, the upper rail12C includes a main portion62. The main portion62includes vertical wall portions31C and a bent portion32C. A lightening portion63(an opening portion) may be provided at the main portion62. That is, because the seat load is received by the shaft member50, the main portion62is not required to include the high strength. As a result, the weight of the upper rail12C is reduced while the high support rigidity of the upper rail12C is maintained.

Next, technical ideas and effects thereof, which may be grasped from the aforementioned embodiment will be described. (A) According to the seat slide apparatus for the vehicle, the threaded portion52is used for fastening the bracket13(i.e., the support member) which is provided at the upper portion of the upper rail12,12B,12C for supporting the seat1. As a result, the seat1is supported reliably.

(B) According to the seat slide apparatus for the vehicle, the upper rail12C includes the main portion62which includes the vertical wall portions31C and the bent portion32C, and the lightening portion63is provided at the main portion62. As a result, the weight of the upper rail12C is reduced.

According to the aforementioned embodiment, the seat slide apparatus for the vehicle includes the upper rail12,12B,12C configured to support the seat1at the upper portion of the upper rail12,12B,12C, the lower rail11supporting the upper rail12,12B,12C in a manner that the upper rail12,12B,12C and the lower rail11are movable relative to each other, and the shaft member50extended in the lengthwise direction of the upper rail12,12B,12C, wherein the upper rail12,12B,12C includes the pair of vertical wall portions31,31B,31C extended in the upper/lower direction, the upper rail12,12B,12C includes the bent portion32,32B,32C connecting the vertical wall portions31,31B,31C to each other at the upper portions of the vertical wall portions31,31B,31C and the shaft member50is provided at the inner side of the bent portion32,32B,32C, and the shaft member50includes the threaded portion52provided at each end thereof in the axial direction, the bent portion32,32B,32C opening in the axial direction of the shaft member50includes the lengthwise-direction-end portions51, and the threaded portions52of the shaft member50face the lengthwise-direction-end portions51of the bent portion32,32B,32C.

According to the above-described configuration, the bolt55is threadedly attached to each of the threaded portions52of the shaft member50via the lengthwise-direction-end portion51of the bent portion32,32B,32C. Thus, the seat1(or the bracket13for supporting the seat1) is fastened to the upper portion of the upper rail12,12B,12C with the fastening force of the bolts55. In addition, the shaft member50serves as the structural body, and thus the support rigidity of the upper rail12,12B,12C is enhanced along the entire length thereof. That is, because the seat load is received by the shaft member50, the deformation is not likely to occur to the vertical wall portions31,31B,31C and the bent portion32,32B,32C which constitute an outer shell (that is, the main portion62) of the upper rail. Particularly, the bending strength of the upper rail12,12B,12C in the lengthwise direction thereof may be enhanced significantly, thereby ensuring the high reliability. In addition, at the shaft member50, the tensile force which elongates or pulls out the shaft member50is caused by the fastening which is achieved by threaded portion52provided at each of the axial ends of the shaft member50. Thus, the fastened state is maintained stably.

Consequently, with the simple configuration, a higher support rigidity of the upper rail12,12B,12C is ensured.

According to the aforementioned embodiment, the upper rail12,12B,12C includes the receiving portion60,60B supporting the lower portion of the shaft member50.

According to the above-described configuration, the shaft member50is held at the inner side of the bent portion32,32B,32C against the seat load in the direction in which the shaft member50is pushed downwardly. Consequently, the high support rigidity is ensured.

According to the aforementioned embodiment, the bent portion32,32C includes the annular shape to which the shaft member50is fitted.

According to the above-described configuration, the shaft member50is maintained at the inner side of the bent portion32,32C easily and reliably with the simple configuration. Thus, the high support rigidity is assured.

According to the aforementioned embodiment, the shaft member50is held at the inner side of the bent portion32,32B,32C against the seat load in the direction in which the shaft member50is pushed downwardly. Consequently, the high support rigidity is ensured.

According to the above-described configuration, the shaft member50is maintained at the inner side of the bent portion32,32C easily and reliably with the simple configuration. Thus, the high support rigidity is assured.

According to the aforementioned embodiment, the upper rail12includes the tightened portion61which connects the vertical wall portions31to each other and reduces the diameter of the annular shape of the bent portion32.

According to the above-described configuration, after the shaft member50is arranged at the inner side of the bent portion32, the diameter of the annular shape of the bent portion32is reduced and the shaft member50is attached to the inner side of the bent portion32by pressure (that is, the shaft member50is fitted to the inner side of the bent portion32). Consequently, the shaft member50is held at the inside of the bent portion32easily and reliably.

According to the aforementioned embodiment, the shaft member50includes the axial length L1that is set to be shorter than the length L2of the bent portion32.

According to the above-described configuration, the “elongation allowance δ” for elongation caused by the fastening is provided at the shaft member50in advance, and thus the positioning of the upper rail12and the member fastened to the upper rail12is performed easily. Consequently, the fastening which is achieved by the threaded portions52is reliably ensured.

According to the aforementioned embodiment, the seat slide apparatus includes the buffer material58interposed between the bent portion32and the shaft member50.

According to the above-described configuration, the buffer material58is interposed between the bent portion32and the shaft member50, and thus the resonance frequency is lowered, or the resonance amplitude is reduced. As a result, the damping effect of the resonance is enhanced.

According to the aforementioned embodiment, the shaft member50is pre-coated with the buffer material58.

According to the above-described configuration, the vibration-proof effects and the sound-proof effects are obtained easily at low costs.

According to the aforementioned embodiment, the shaft member50corresponds to the pipe53which is hollow.

According to the above-described configuration, the weight of the shaft member50is reduced while the high strength is maintained. In addition, because the internal thread is formed at the inner periphery of the axial end portions of the pipe53, the threaded portions52are provided easily.

According to the aforementioned embodiment, the pipe53includes the threaded portion52provided at the inner periphery of each end of the pipe53in the axial direction thereof.

According to the aforementioned embodiment, the threaded portion52is configured to fasten the bracket13(i.e., the support member) provided at the upper portion of the upper rail12,12B,12C and supporting the seat1.

According to the above-described configuration, the seat1is supported reliably.

According to the aforementioned embodiment, the upper rail12C includes the main portion62which includes the vertical wall portions31C and the bent portion32C, and the lightening portion63is provided at the main portion62.

According to the above-described configuration, the weight of the upper rail12C is reduced.

According to the aforementioned embodiment, a seat apparatus for a vehicle includes the seat slide apparatus for the vehicle including the upper rail12,12B,12C configured to support the seat1at the upper portion of the upper rail12,12B,12C, the lower rail11supporting the upper rail12,12B,12C in a manner that the upper rail12,12B,12C and the lower rail11are movable relative to each other, and the shaft member50extended in the lengthwise direction of the upper rail12,12B,12C, wherein the upper rail12,12B,12C includes the pair of vertical wall portions31,31B,31C extended in the upper/lower direction, the upper rail12,12B,12C includes the bent portion32,32B,32C connecting the vertical wall portions31,31B,31C to each other at the upper portions of the vertical wall portions31,31B,31C and the shaft member50is provided at the inner side of the bent portion32,32B,32C, the shaft member50includes the threaded portion52provided at each end thereof in the axial direction, the bent portion32,32B,32C opening in the axial direction of the shaft member50includes the lengthwise-direction-end portions51, and the threaded portions52of the shaft member50face the lengthwise-direction-end portions51of the bent portion32,32B,32C, the seat1, the bracket13provided at the upper portion of the upper rail12,12B,12C and supporting the seat1, and the bolt55threadedly attached to each of the threaded portions52, and connecting the bracket13, the upper rail12,12B,12C and the shaft member50to each other.

According to the aforementioned embodiment, the bracket13includes the flange portion54facing the lengthwise-direction-end portion51of the bent portion32,32B,32C, and the insertion hole56into which the bolt55is inserted is provided at the flange portion54.

According to the aforementioned embodiment, the shaft member50includes the elongation allowance δ for the elongation caused by the fastening which is obtained by the bolt55.

According to the above-described configuration, the positioning of the bracket13is performed easily and the bracket13is fixed at the upper rail12,12B,12C reliably.