Patent Description:
Known is an electrically powered slide rail for an automobile that includes a lower rail, an upper rail, worms interposed between the lower rail and the upper rail and configured to be actuated by an electric motor, and a worm meshing means provided on both the upper rail and the lower rail to threadably engage the worms. See <CIT>, for example. There are four worms; two of them on the upper side engage grooves arranged at a prescribed pitch on the lower surface of the upper rail while the remaining two on the lower side engage similar grooves provided on the lower rail.

<CIT> discloses an electrically powered slide rail having a lower rail and an upper rail. The upper rail supports an electric motor having a threaded portion on its output shaft to engage with notches on the lower rail.

<CIT> discloses a motor driven slide device for a vehicle seat having upper and lower rails with a drive unit located in a hollow space therebetween.

<CIT> discloses a slide device having an upper rail and a lower rail. A feed screw on the upper rail engages with slits provided on the lower rail.

However, if the worms and the electric motor are not fixed to either the lower rail or the upper rail, the worms tend to tilt with respect to the lower rail and the upper rail with the result that the rotation of the worms may be hindered. As a result, the operation of the electrically powered slide rail may be hindered. In addition, owing to such hindrance to the operation of the electrically powered slide rail, abnormal noise and rattling are likely to occur.

In view of such a problem of the prior art, a primary object of the present invention is to provide an electrically powered slide rail that can operate smoothly. Another object of the present invention is to provide a vehicle seat that is capable of a smooth sliding movement.

To achieve such an object, an aspect of the present invention provides an electrically powered slide rail (<NUM>), comprising: a rail (<NUM>) having a channel-shaped cross section and extending in a fore and aft direction; a slider (<NUM>) received by the rail and slidably engaged by the rail; a screw assembly (<NUM>) including a screw member (<NUM>, <NUM>) supported by the slider so as to be rotatable around an axial line extending in the fore and aft direction; an electric motor (<NUM>) supported by the slider and configured to rotate the screw member; and a screw engaging portion (<NUM>, <NUM>) formed in the rail so as to extend in the fore and aft direction and engage the screw member; wherein the rail is provided with a first side wall (<NUM>) and a second side wall (<NUM>) opposing each other, and the screw engaging portion includes a first screw engaging portion (<NUM>) formed on the first side wall, and a second screw engaging portion (<NUM>) formed on the second side wall; characterized in that the screw member includes a first screw member (<NUM>) that engages with the first screw engaging portion and a second screw member (<NUM>) that engages with the second screw engaging portion, the first screw member and the second screw member being arranged parallel to each other between the first screw engaging portion and the second screw engaging portion, and the first side wall and the second side wall are respectively formed with protrusions (<NUM>) that protrude toward each other and extend in the fore and aft direction, and the screw engaging portions include a plurality of engaging holes (<NUM>) formed in the protrusions along the fore and aft direction.

Since the motor and the screw assembly are fixed to the slider, the screw member is prevented from tilting with respect to the screw engaging portion. Therefore, the screw member can be engaged with the screw engaging portion at an appropriate angle, and the screw member can rotate smoothly. As a result, it is possible to provide an electrically powered slide rail that can operate smoothly. Further, since the electric motor is attached to the slider received by the rail, the outer profile of the electric rail device can be minimized in size. The shaft for transmitting the rotational force of the electric motor to the screw member can be shortened. Further, since the screw member rotatably supported by the slider threads with the screw engaging portion provided on the rail, the play (tolerance) can be reduced as compared with the configuration where the screw engaging portions are provided on both the slider and the rail, and the screw members thread with the screw engaging portions provided on both the slider and the rail. Further, since the electric motor and the screw assembly are provided on the slider, the moving stroke of the slider can be easily extended by extending the length the rail.

Since the screw assembly includes both the first screw member and the second screw member, the screw assembly can be made small in size although engaging with both the first screw engaging portion and the second screw engaging portion. Further, since the direction of the reaction force received by the first screw member from the first screw engaging portion and the direction of the reaction force received by the second screw member from the second screw engaging portion are opposite to each other, the first screw member and the first screw engaging portion can be reliably engaged with each other, and the second screw member and the second screw engaging portion can be reliably engaged with each other. Further, since the first screw engaging portion and the second screw engaging portion are formed, respectively, on the first side wall and the second side wall opposing each other, foreign matter is prevented from depositing in the first screw engaging portion and the second screw engaging portion.

The first side wall and the second side wall are respectively formed with protrusions (<NUM>) that protrude toward each other and extend in the fore and aft direction, and the screw engaging portions includes a plurality of engaging holes (<NUM>) formed in the protrusions along the fore and aft direction. Thereby, the screw engaging portion and the teeth of the screw member can be engaged with each other to an increased extent.

Preferably, in this configuration, the screw assembly includes a gear case (<NUM>) that rotatably supports the first screw member and the second screw member, and a first bracket (<NUM>) that supports the gear case on the slider, the gear case having an opening (<NUM>) that laterally exposes the first screw member and the second screw member.

Thereby, the assembling the screw assembly having the first screw member and the second screw member to the slider can be facilitated.

Preferably, in this configuration, the first bracket is provided with a first connecting portion (42A) extending forward from a front part of the gear case and a second connecting portion (42B) extending rearward from a rear part of the gear case, the first bracket being connected to the slider at the first connecting portion and the second connecting portion.

Thereby, the first bracket can support the first gear case in a stable manner.

Preferably, in this configuration, the first bracket is formed by a single-piece metallic member including a support portion (42C) extending from the first connecting portion to the second connecting portion, the gear case being positioned between the slider and the support portion.

Thus, the closed cross section structure formed by the slider and the first bracket can support the gear case in stable manner.

Preferably, in this configuration, the electrically powered slide rail further comprises a second bracket (<NUM>) connected to a part of the slider in front of or behind the first bracket for supporting the electric motor, the second bracket supporting an end of the electric motor on a side of the screw members as a cantilever.

Since the electric motor is supported by the second bracket forming a cantilever, the electric motor can be slightly tilted with respect to the screw assembly. As a result, a small misalignment between the rotary shaft of the electric motor and the screw assembly can be tolerated.

Preferably, in this configuration, the slider is formed in a channel shape by including a base portion (<NUM>), and a third side wall (<NUM>) and a fourth side wall (<NUM>) extending from the base portion toward a bottom portion of the rail, the third side wall opposing the first side wall, the fourth side wall opposing the second side wall, and the second bracket is connected to the base portion while the electric motor is positioned between the third side wall and the fourth side wall.

Thereby, the electric motor can be placed inside the slider so as to reduce the outer profile of the electrically powered slide rail in size.

Preferably, in this configuration, the first screw member passes through an opening (<NUM>) formed in the third side wall to engage with the first screw engaging portion, and the second screw member passes through an opening formed in the fourth side wall to engage with the second screw engaging portion.

Thereby, the screw assembly can be placed close to the electric motor. As a result, the shaft that transmits the driving force of the electric motor to the screw assembly can be reduced in length so that the rotation of the screw member can be performed in a smooth manner.

Preferably, in this configuration, the gear case is provided with a pair of first bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a front end and a rear end of the first screw member, a pair of second bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a front end and a rear end of the second screw member, and a pair of third bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a drive shaft (<NUM>) connected to a rotary shaft (36A) of the electric motor. Further, the drive shaft is provided with a pair of drive gears (43A) arranged along the fore and aft direction, the first screw member is provided with a pair of first gears (38B) arranged along the fore and aft direction meshing with the corresponding drive gears, and the second screw members is provided with a pair of second gears (39B) arranged along the fore and aft direction meshing with the corresponding drive gears.

According to this aspect of the present invention, the rotational force of the electric motor can be reliably transmitted to the first screw member and the second screw member. Further, the first screw member, the second screw member, and the drive shaft can be arranged in a stable and accurate manner.

Preferably, in this configuration, the rotary shaft of the electric motor is connected to the drive shaft via a speed reduction unit.

Thereby, the rotation of the drive shaft can be reduced in speed so as to generate the torque required for the first screw member and the second screw member.

Preferably, in this configuration, the rail is internally provided with a conductive strip (<NUM>) extending in the fore and aft direction and connected to a power source, and an electrical insulating sheet (<NUM>) provided between the rail and the conductive strip, and the electric motor is provided with a conductive contact terminal (<NUM>) that is in sliding contact with the conductive strip.

Thereby, the need for a wire harness for supplying electric power to the electric motor can be eliminated.

Preferably, in this configuration, the electrically insulating sheet has an extension (63A) along a side edge thereof, the extension being bent inward above the conductive strip to oppose the conductive strip with a gap defined therebetween, and the contact terminal extends into the gap defined between the extension and the conductive strip.

Thereby, foreign matter is prevented from coming into contact with the conductive strip.

Yet another aspect of the present invention provides a vehicle seat (<NUM>) provided with the electrically powered slide rail defined above, wherein the rail is connected to a floor (<NUM>) of a vehicle, and the slider is connected to a seat cushion (<NUM>).

Thus, the present invention provides a vehicle seat capable of smoothly sliding movement.

Preferably, in this configuration, the rail is received in a rail groove (<NUM>) formed in the floor.

Thereby, the rail can be placed in the rail groove so that the rail does not protrude from the floor.

An aspect of the present invention provides an electrically powered slide rail (<NUM>), comprising: a rail (<NUM>) having a channel-shaped cross section and extending in a fore and aft direction; a slider (<NUM>) received by the rail and slidably engaged by the rail; a screw assembly (<NUM>) including a screw member (<NUM>, <NUM>) supported by the slider so as to be rotatable around an axial line extending in the fore and aft direction; an electric motor (<NUM>) supported by the slider and configured to rotate the screw member; and a screw engaging portion (<NUM>, <NUM>) formed in the rail so as to extend in the fore and aft direction and engage the screw member.

According to this aspect of the present invention, since the motor and the screw assembly are fixed to the slider, the screw member is prevented from tilting with respect to the screw engaging portion. Therefore, the screw member can be engaged with the screw engaging portion at an appropriate angle, and the screw member can rotate smoothly. As a result, it is possible to provide an electrically powered slide rail that can operate smoothly. Further, since the electric motor is attached to the slider received by the rail, the outer profile of the electric rail device can be minimized in size. The shaft for transmitting the rotational force of the electric motor to the screw member can be shortened. Further, since the screw member rotatably supported by the slider threads with the screw engaging portion provided on the rail, the play (tolerance) can be reduced as compared with the configuration where the screw engaging portions are provided on both the slider and the rail, and the screw members thread with the screw engaging portions provided on both the slider and the rail. Further, since the electric motor and the screw assembly are provided on the slider, the moving stroke of the slider can be easily extended by extending the length the rail.

Preferably, in this configuration, the rail is provided with a first side wall (<NUM>) and a second side wall (<NUM>) opposing each other, the screw engaging portion includes a first screw engaging portion (<NUM>) formed on the first side wall, and a second screw engaging portion (<NUM>) formed on the second side wall, and the screw member includes a first screw member (<NUM>) that engages with the first screw engaging portion and a second screw member (<NUM>) that engages with the second screw engaging portion, the first screw member and the second screw member being arranged parallel to each other between the first screw engaging portion and the second screw engaging portion.

According to this aspect of the present invention, since the screw assembly includes both the first screw member and the second screw member, the screw assembly can be made small in size although engaging with both the first screw engaging portion and the second screw engaging portion. Further, since the direction of the reaction force received by the first screw member from the first screw engaging portion and the direction of the reaction force received by the second screw member from the second screw engaging portion are opposite to each other, the first screw member and the first screw engaging portion can be reliably engaged with each other, and the second screw member and the second screw engaging portion can be reliably engaged with each other. Further, since the first screw engaging portion and the second screw engaging portion are formed, respectively, on the first side wall and the second side wall opposing each other, foreign matter is prevented from depositing in the first screw engaging portion and the second screw engaging portion.

Preferably, in this configuration, the gear case is provided with a pair of first bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a front end and a rear end of the first screw member, a pair of second bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a front end and a rear end of the second screw member, and a pair of third bearing portions (<NUM>) arranged along the fore and aft direction to rotatably support a drive shaft (<NUM>) connected to a rotary shaft (36A) of the electric motor. Further, the drive shaft is provided with a drive gear (43A), the first screw member is provided with a first gear (38B) meshing with the drive gear, and the second screw members is provided with a second gear (39B) meshing with the drive gear.

Preferably, in this configuration, the first side wall and the second side wall are respectively formed with protrusions (<NUM>) that protrude toward each other and extend in the fore and aft direction, and the screw engaging portions includes a plurality of engaging holes (<NUM>) formed in the protrusions along the fore and aft direction.

Thereby, the screw engaging portion and the teeth of the screw member can be engaged with each other to an increased extent.

Embodiments of the present invention are described in the following with reference to the appended drawings. The electrically powered slide rail includes a rail and a slider that can slidably move relative to the rail. The rail is connected to a first structure and the slider is connected to a second structure. As the slider moves relative to the rail, the electrically powered slide rail causes the second structure to move relative to the first structure. The electrically powered slide rail is provided, for example, between the floor of a vehicle and the seat to move the seat relative to the floor. Further, the electrically powered slide rail may also be provided between a base and a work holder to move the work holder relative to the base.

An electrically powered slide rail <NUM> and a vehicle seat <NUM> fitted with the electrically powered slide rail <NUM> according to an embodiment of the present invention are described in the following with reference to the appended drawings. As shown in <FIG>, the vehicle seat <NUM> is provided with at least one electrically powered slide rail <NUM> in a lower part thereof, and is connected to the floor <NUM> of the vehicle via the electrically powered slide rail <NUM>. The vehicle seat <NUM> includes a seat cushion <NUM> that supports the buttocks of the occupant, and a seat back <NUM> that extends upward from a rear part of the seat cushion <NUM> to support the back of the occupant. The electrically powered slide rail <NUM> is provided between the floor <NUM> and the seat cushion <NUM> to support the seat cushion <NUM> so as to be slidable with respect to the floor <NUM>. The vehicle seat <NUM> is preferably provided with a pair of such electrically powered slide rails <NUM>.

As shown in <FIG>, the electrically powered slide rail <NUM> includes a rail <NUM> extending in the fore and aft direction and a slider <NUM> slidably engaged by the rail <NUM>. The extending direction of the rail <NUM> is defined as the fore and aft direction. The extending direction of the rail <NUM> may or may not coincide with the fore and aft direction of the vehicle. In other words, the extending direction of the rail <NUM> in this embodiment does not limit the extending direction thereof as mounted on the vehicle. In the present embodiment, the extending direction of the rail <NUM> coincides with the fore and aft direction of the vehicle. In this embodiment, the slider <NUM> is provided above the rail <NUM>. Therefore, the rail <NUM> may be referred to as a lower rail and the slider <NUM> as an upper rail.

As shown in <FIG> and <FIG>, the rail <NUM> has a channel-shaped cross section. More specifically, the rail <NUM> includes a rail bottom wall <NUM> having vertically facing surfaces, left and right rail outer side walls <NUM> which extend upward from the left and right edges of the rail bottom wall <NUM>, respectively, and have laterally facing surfaces, a left and right rail upper walls <NUM> extending from the upper edges of the left and right outer side walls <NUM>, respectively, toward each other and having vertically facing surfaces, and left and right inner side walls <NUM> extending downward from the inner edges of the respective left and right rail upper walls <NUM>, respectively. The left and right rail inner side walls <NUM> correspond to the first side wall and the second side wall of the claims, respectively.

The rail bottom wall <NUM>, the left and right rail outer side walls <NUM>, the left and right rail upper walls <NUM>, and the left and right rail inner side walls <NUM> all extend in the fore and aft direction. The left and right rail outer side walls <NUM> extend parallel to each other and perpendicular to the rail bottom wall <NUM> and so do the left and right rail inner side walls <NUM>. The lower ends of the left and right rail inner side wall walls <NUM> are spaced from the rail bottom wall <NUM>. The rail <NUM> thus defines a rail opening <NUM> extending in the fore and aft direction at the upper end of the rail <NUM>. The rail opening <NUM> is defined by the left and right rail inner side walls <NUM>. The rail <NUM> may be formed by press forming a metal plate. The lateral edges of the rail bottom wall <NUM> may have stepped portions <NUM> that are raised upward. The left and right step portions <NUM> extend in the fore and aft direction, and have upper surfaces that are formed flat.

The rail inner side walls <NUM> are formed with protrusion <NUM> that project toward each other and extend in a fore and aft direction. The cross sections of the left and right protrusions <NUM> may be formed in an arcuate shape or a trapezoidal shape. Each protrusion <NUM> may be arranged at a vertically intermediate part of the corresponding rail inner side wall <NUM>. The upper end portions and the lower end portions of the left and right rail inner side walls <NUM> are arranged on the laterally outer sides of the corresponding protrusions <NUM>.

As shown in <FIG>, the slider <NUM> includes a plate-shaped base portion <NUM> having vertically facing surfaces and positioned at the open end of the rail opening <NUM>, left and right slider inner side walls <NUM> extending toward the rail bottom wall <NUM> or downward from the respective lateral side edges of the base portion <NUM>, left and right slider lower walls <NUM> extending outward from the lower ends of the respective slider inner side walls <NUM>, and left and right slider outer side walls <NUM> extending upward from the outer ends of the respective slider lower walls <NUM>. The left and right slider inner side walls <NUM> correspond to the third side wall and the fourth side wall of the claims, respectively. The base portion <NUM>, the left and right slider inner side walls <NUM>, the left and right slider lower walls <NUM>, and the left and right slider outer side walls <NUM> all extend in the fore and aft direction.

The slider <NUM> may be formed by fastening a plurality of press-formed or roll-formed metal plates to each other. In the present embodiment, the slider <NUM> consists of a first piece 12A providing the base portion <NUM>, the left slider inner side wall <NUM>, the left slider lower wall <NUM>, and the left slider outer side wall <NUM>, and a second piece 12B providing the base portion <NUM>, the right slider inner side wall <NUM>, the right slider lower wall <NUM>, and the right slider outer side wall <NUM>. The slider <NUM> is formed by overlapping the first piece 12A and the second piece 12B with each other at the respective base portions <NUM> thereof, and fastening them together. In another embodiment, the slider <NUM> is formed from a single-piece press-formed or roll-formed metal plate. The fore and aft length of the slider <NUM> is set shorter than the fore and aft length of the rail <NUM>. The slider <NUM> is connected to the seat cushion <NUM> at the base portion <NUM> thereof.

The base portion <NUM> may be positioned either above the left and right rail upper walls <NUM>, or below the left and right rail upper walls <NUM>. The left and right slider inner side walls <NUM> laterally face each other and are spaced from each other by a certain distance. The left and right slider inner side walls <NUM> are positioned between the left and right rail inner side walls <NUM>. Each slider inner side wall <NUM> laterally oppose the corresponding rail inner side wall <NUM> with a certain gap defined therebetween. Each slider lower wall <NUM> extends laterally through a space defined between the rail bottom wall <NUM> and the lower end of the corresponding rail inner side wall <NUM>. Each slider outer side wall <NUM> is positioned laterally between the rail outer side wall <NUM> and the rail inner side wall <NUM> on the corresponding side. A plurality of rollers <NUM> are rotatably supported on the laterally outer side of each slider outer side wall <NUM>. Each roller <NUM> has a laterally extending rotational axis, and is in contact with the rail bottom wall <NUM>. In the present embodiment, each roller <NUM> is in rolling contact with the upper surface of the step portion <NUM> of the rail bottom wall <NUM>. The slider <NUM> can slidably and smoothly move along the rail <NUM> by contacting the rail <NUM> via the rollers <NUM>. Owing to this arrangement, the slider <NUM> is received by the rail <NUM> and slidably engages with the rail <NUM>. In another embodiment, the slider <NUM> is supported by the rail <NUM> via a ball bearing or a roller bearing.

The left and right slider inner side walls <NUM> are respectively formed with recessed parts <NUM> that are recessed toward each other, and extend in the fore and aft direction so that a corresponding protrusion is formed on the back side the recessed part <NUM> of each slider inner side wall <NUM>. The cross section of the left and right recesses <NUM> when viewed in the fore and aft direction is preferably formed in an arcuate shape or a trapezoidal shape. Each recessed part <NUM> may be positioned at a vertically intermediate part of the corresponding slider inner side wall <NUM>. Each recessed part <NUM> is positioned so as to laterally oppose the corresponding protrusion <NUM> of the rail <NUM>.

The slider <NUM> is formed by the base portion <NUM> and the left and right slider inner side walls <NUM> in a channel shape that opens toward the rail bottom wall <NUM>, or in other words downward. As shown in <FIG> and <FIG>, a screw assembly <NUM> and an electric motor <NUM> are supported on the lower surface of the base portion <NUM>. The screw assembly <NUM> includes screw members <NUM>, <NUM> rotatably supported by the slider <NUM> around a rotational axis extending in the fore and aft direction. The electric motor <NUM> is supported by the slider <NUM> and rotates the screw members <NUM> and <NUM>.

As shown in <FIG> and <FIG>, in the present embodiment, the screw members <NUM> and <NUM> include a first screw member <NUM> and a second screw member <NUM>. The first screw member <NUM> and the second screw member <NUM> are each provided with a screw thread 38A, 39A on the outer peripheral surface of an intermediate part thereof with respect to the longitudinal direction. The number of threads 38A and 39A (pitch) may be determined by the size of the electrically powered slide rail <NUM> and the required strength in the longitudinal direction of the electrically powered slide rail <NUM>. For example, when it is desired to increase the required strength, it is preferable to increase the number of threads 38A and 39A. As shown in <FIG> and <FIG>, the screw assembly <NUM> includes a gear case <NUM> that rotatably supports the first screw member <NUM> and the second screw member <NUM>, and a first bracket <NUM> for supporting the gear case <NUM> on the slider <NUM>.

As shown in <FIG> and <FIG>, the gear case <NUM> is formed in the shape of a rectangular box elongated in the fore and aft direction. The gear case <NUM> rotatably supports the first screw member <NUM>, the second screw member <NUM>, and a drive shaft <NUM> connected to a rotary shaft 36A of the electric motor <NUM>. The first screw member <NUM>, the second screw member <NUM>, and the drive shaft <NUM> all extend in the fore and aft direction, and are arranged in parallel with each other in the gear case <NUM>. The gear case <NUM> includes a box-shaped outer case 41A forming an outer shell, and a front support member 41B and a rear support member 41C supported by the front end and the rear end of the outer case 41A, respectively. The front support member 41B is provided with a first bearing portion <NUM> rotatably supporting the front end of the first screw member <NUM>, a second bearing portion <NUM> rotatably supporting the front end of the second screw member <NUM>, and a third bearing portion <NUM> rotatably supporting the drive shaft <NUM>. The rear support member 41C is provided with a first bearing portion <NUM> rotatably supporting the rear end of the first screw member <NUM>, a second bearing portion <NUM> rotatably supporting the rear end of the second screw member <NUM>, and a third bearing portion <NUM> rotatably supporting the drive shaft <NUM>.

The first screw member <NUM> extends along the left side of the gear case <NUM>, and the second screw member <NUM> extends along the right side of the gear case <NUM>. The drive shaft <NUM> is positioned under an intermediate region between the first screw member <NUM> and the second screw member <NUM>. The drive shaft <NUM> has a drive gear 43A located in the gear case <NUM>. The first screw member <NUM> has a first gear 38B that meshes with the drive gear 43A. The second screw member <NUM> has a second gear 39B that meshes with the drive gear 43A. The drive gear 43A, the first gear 38B, and the second gear 39B may each consist of a spur gear. When the drive shaft <NUM> rotates, the first screw member <NUM> and the second screw member <NUM> rotate in the same direction. The first gear 38B and the second gear 39B may be symmetrical to each other.

As shown in <FIG> and <FIG>, the gear case <NUM> has a pair of case openings <NUM> that expose first screw member <NUM> and the second screw member <NUM> on the respective sides. The thread 38A of the first screw member <NUM> passes through the case opening <NUM> formed on the left side of the gear case <NUM> and projects to the left. Similarly, the thread 39A of the second screw member <NUM> passes through the case opening <NUM> formed on the right side of the gear case <NUM> and projects to the right. The case openings <NUM> are formed in the outer case 41A.

The first bracket <NUM> extends in the fore and aft direction, and has a first connecting portion 42A provided at the front end thereof and a second connecting portion 42B provided at the rear end thereof. The first bracket <NUM> is connected to the lower surface of the base portion <NUM> of the slider <NUM> at the first connecting portion 42A and the second connecting portion 42B. The first bracket <NUM> has a support portion 42C extending from the first connecting portion 42A to the second connecting portion 42B. The first bracket <NUM> may be an integral metal member including the first connecting portion 42A, the second connecting portion 42B, and the support portion 42C. The support portion 42C includes a part located below the first connecting portion 42A and the second connecting portion 42B. The support portion 42C of the first bracket <NUM> forms a closed cross section structure in cooperation with the base portion <NUM>. The gear case <NUM> is positioned between the base portion <NUM> of the slider <NUM> and the support portion 42C. The first bracket <NUM> is formed by bending a metal plate. The first connecting portion 42A extends forward from the front part of the gear case <NUM>, and the second connecting portion 42B extends rearward from the rear part of the gear case <NUM>. The first connecting portion 42A and the second connecting portion 42B may be fastened to the base portion <NUM> by using fastening members such as screws and rivets. The distance between the fastening points of the first connecting portion 42A and the second connecting portion 42B is set to be greater than the fore and aft length of the gear case <NUM>.

Behind the first bracket <NUM> is located a second bracket <NUM> for supporting the electric motor <NUM> on the base portion <NUM> of the slider <NUM>. The second bracket <NUM> has a connecting portion 51A to be connected to the base portion <NUM>, and a supporting portion 51B extending from the base portion <NUM> away from the connecting portion 51A or in other words downward. The support portion 51B extends orthogonally to the connecting portion 51A so that the second bracket <NUM> is formed in an L shape. The electric motor <NUM> is connected to the support portion 51B at one end thereof. In the present embodiment, the electric motor <NUM> is positioned under the connecting portion 51A, and the second bracket <NUM> supports the end portion of the electric motor <NUM> on the side of the screw members <NUM> and <NUM> in the manner of a cantilever.

The rear end of the drive shaft <NUM> projects rearward from the rear support member 41C of the gear case <NUM>, and extends rearward through a through hole formed in the first bracket <NUM>. The rotary shaft 36A of the electric motor <NUM> is connected to the rear end of the drive shaft <NUM>. The rotary shaft 36A and the drive shaft <NUM> may be connected to each other by a shaft coupling. Alternatively, the rotary shaft 36A and the drive shaft <NUM> may be connected to each other via a shape fit structure. The rotary shaft 36A of the electric motor <NUM> and the drive shaft <NUM> are arranged on the same straight line. The electric motor <NUM> is formed in a cylindrical shape and extends in the fore and aft direction.

A speed reduction unit <NUM> may be provided between the rotary shaft 36A of the electric motor <NUM> and the drive shaft <NUM>. The speed reduction unit <NUM> may be, for example, a planetary gear mechanism. The speed reduction unit <NUM> may be provided on the surface of the support portion 51B of the second bracket <NUM> facing away from the electric motor <NUM>. In another embodiment, the speed reduction unit <NUM> is supported by the rear end surface of the gear case <NUM>. The speed reduction unit <NUM> is an optional element, and may be omitted.

The screw assembly <NUM>, the electric motor <NUM>, the first bracket <NUM>, and the second bracket <NUM> are all positioned under the base portion <NUM> and between the left and right slider inner side walls <NUM>. The left and right slider inner sidewalls <NUM> are each provided with a slider opening <NUM> that is located at a position corresponding to the screw assembly <NUM>. The slider openings <NUM> are formed in the recessed parts <NUM> of the slider inner side walls <NUM>, respectively. The left part of the thread 38A of the first screw member <NUM> passes through the case opening <NUM> on the left side of the gear case <NUM> and the slider opening <NUM> on the left slider inner side wall <NUM>, and projects to the left of the left slider inner side wall <NUM> of the slider <NUM>. Similarly, the right part of the thread 39A of the second screw member <NUM> passes through the case opening <NUM> on the right side of the gear case <NUM> and the slider opening <NUM> of the right slider inner side wall <NUM>, and projects to the right of the right slider inner side wall <NUM>.

As shown in <FIG> and <FIG>, the rail <NUM> is formed with screw engaging portions <NUM>, <NUM> extending in the fore and aft direction and engaging with the screw members <NUM>, <NUM>, respectively. <FIG> shows only the rail inner side wall <NUM> of the rail <NUM>. The screw engaging portions <NUM> and <NUM> include a first screw engaging portion <NUM> formed on the left rail inner side wall <NUM> and meshing with the thread 38A of the first screw member <NUM>, and a second screw engaging portion <NUM> formed on the right rail inner side wall <NUM> and meshing with the thread 39A of the second thread member <NUM>. The first screw engaging portion <NUM> and the second screw engaging portion <NUM> are formed on the protrusions <NUM> of the corresponding rail inner side walls <NUM>. The first screw engaging portion <NUM> and the second screw engaging portion <NUM> each include a plurality of engaging holes <NUM> formed in the protrusion <NUM> at regular intervals along the fore and aft direction. The first screw member <NUM> meshes or threads with the engaging holes <NUM> of the first screw engaging portion <NUM> at the left part of the thread 38A of the first screw member <NUM>, and rotates around a rotational axis extending in the fore and aft direction so as to move in the fore and aft direction relative to the first screw engaging portion <NUM>. Similarly, the second screw member <NUM> meshes of threads with the engaging holes <NUM> of the second screw engaging portion <NUM> at the right part of the thread 39A of the second screw member <NUM>, and rotates around a rotational axis extending in the fore and aft direction so as to move in the fore and aft direction relative to the second screw engaging portion <NUM>.

The rotation of the electric motor <NUM> is transmitted to the first screw member <NUM> and the second screw member <NUM> via the rotary shaft 36A, the drive shaft <NUM>, the drive gear 43A, the first gear 38B or the second gear 39B as the case may be. As a result, the first screw member <NUM> and the second screw member <NUM> rotate in the same direction. When the first screw member <NUM> and the second screw member <NUM> rotate, the first screw member <NUM> and the second screw member <NUM> move in the fore and aft direction with respect to the first screw engaging portion <NUM> and the second screw engaging portion <NUM> so that the slider <NUM> moves in the fore and aft direction with respect to the rail <NUM>.

As shown in <FIG> and <FIG>, the electrically powered slide rail <NUM> has a power feeding device <NUM> for supplying electric power to the electric motor <NUM>. The power feeding device <NUM> extends in the interior of the rail <NUM> in the fore and aft direction, and includes a pair of conductive strips <NUM> connected to a power source <NUM>, an electric insulating sheet <NUM> provided between the rail <NUM> and the conductive strips <NUM>, and a pair of conductive contact terminals <NUM> that are provided on the electric motor <NUM> and are in sliding contact with the corresponding conductive strips <NUM>. In the present embodiment, the electric insulating sheet <NUM> is provided on the upper surface of the rail bottom wall <NUM>, and the conductive strips <NUM> are provided on the upper surface of the electric insulating sheet <NUM>. The conductive strips <NUM> are strip-shaped metal sheets which are provided as a pair, one on the left and the other on the right, and extend in the fore and aft direction. The left and right conductive strips <NUM> are arranged along the left and right side edges of the electrically insulating sheet <NUM> extending in the fore and aft direction, respectively.

The electrical insulating sheet <NUM> has an extension 63A bent inward and above the corresponding conductive strip <NUM> on each side edge thereof. Each extension 63A opposes the corresponding conductive strip <NUM> on the corresponding side with a gap defined therebetween. In other words, each extension 63A extends above the corresponding conductive strip <NUM> either on the left or right side. The extensions 63A prevent foreign matter from coming into contact with the conductive strips <NUM>. The left and right side edges of the electrical insulating sheet <NUM> may each have an inclined portion 63B inclined upward toward the laterally outer side. The left and right conductive strips <NUM> may be provided on the upper surface of the inclined portions 63B. In this case, foreign matter is more effectively prevented from coming into contact with the conductive strips <NUM>.

Each contact terminal <NUM> extends from the electric motor <NUM> into a space defined between the extension 63A and the conductive strip <NUM> on the corresponding side. The contact terminal <NUM> is urged toward the conductive strip <NUM> owing to the elasticity thereof. The contact terminals <NUM> may each consist of, a piece of electroconductive metal, for example. In the present embodiment, the electric motor <NUM> has a left contact terminal <NUM> that slides overs the left conductive strip <NUM> and a right contact terminal <NUM> that slides over the right conductive strip <NUM>. The electric motor <NUM> receives electric power from the power source <NUM> via the left and right conductive strips <NUM> and the left and right contact terminals <NUM>. When the slider <NUM> moves in the fore and aft direction with respect to the rail <NUM>, the left and right contact terminals <NUM> slide in the fore and aft direction with respect to the corresponding conductive strips <NUM>, and the left and right contact terminals <NUM> maintain contact with the corresponding conductive strip <NUM> throughout this process.

The power feeding device <NUM> is connected to the power source <NUM> via a control unit <NUM>. The control unit <NUM> is provided on the floor <NUM>, for example. The control unit <NUM> is an electronic control unit, and is connected to the power source <NUM>, the left and right conductive strips <NUM> of each electrically powered slide rail <NUM>, and an operation switch <NUM>. The operation switch <NUM> is provided with a button corresponding to forward movement and another button corresponding to backward movement. The control unit <NUM> adjusts the electric power supplied to the conductive strips <NUM> according to the signal received from the operation switch <NUM>, and controls the rotational direction and the rotational angle of the electric motor <NUM>. The operator can thus operate the electrically powered slide rail <NUM> by operating the operation switch <NUM> and move the vehicle seat <NUM> in the fore and aft direction with respect to the floor <NUM>. In another embodiment, the electric motor <NUM> is controlled by a wireless signal from a wireless device, independent from the electric power supplied by the conductive strip <NUM>.

Each rail <NUM> of the left and right electrically powered slide rails <NUM> is connected to the floor <NUM> of the vehicle via a bracket or directly. Each rail <NUM> may be received by a rail groove <NUM> formed on the floor <NUM>. The upper surface of the rail upper wall <NUM> of the rail <NUM> may be positioned on the same plane as the upper surface of the floor <NUM>. By positioning the rail <NUM> in the rail groove <NUM>, the rail <NUM> is prevented from protruding from the floor <NUM>. Each of the sliders <NUM> of the left and right electrically powered slide rails <NUM> is connected to the seat cushion <NUM>. The sliders <NUM> of the left and right electrically powered slide rails <NUM> may be connected to each other by a connecting member.

In the electrically powered slide rail <NUM> according to the present embodiment, since the electric motor <NUM> and the screw assembly <NUM> are fixed to the slider <NUM>, the first screw member <NUM> and the second screw member <NUM> are prevented from tilting relative to the first screw engaging portion <NUM> and the second screw engaging portion <NUM>. Therefore, the first screw member <NUM> can thread with the first screw engaging portion <NUM> at an appropriate angle so that the rotation of the first screw member <NUM> can occur in a smooth manner. The same applies to the second screw member <NUM>. Thus, the present invention provides an electrically powered slide rail <NUM> that can operate smoothly. Further, since the electric motor <NUM> is attached to the slider <NUM> which is received by the rail <NUM>, the outer profile of the electrically powered slide rail <NUM> can be minimized in size. Further, since the electric motor <NUM> is placed inside the slider <NUM>, the distance between the electric motor <NUM> and the screw assembly <NUM> can be minimized so that the length of the drive shaft <NUM> connecting the electric motor <NUM> to the screw assembly <NUM> is minimized. As a result, the bending of the drive shaft <NUM> is reduced so that the screw assembly <NUM> can rotate smoothly.

Since the screw assembly <NUM> is provided with two members, the first screw member <NUM> and the second screw member <NUM>, the screw assembly <NUM> can be small in sized although both the first screw engaging portion <NUM> and the second screw engaging portion <NUM> are engaged. Further, since the direction of the reaction force received by the first screw member <NUM> from the first screw engaging portion <NUM> and the direction of the reaction force received by the second screw member <NUM> from the second screw engaging portion <NUM> are opposite from each other, the first screw member <NUM> and the first screw engaging portion <NUM> can be securely engaged with each other, and the second screw member <NUM> and the second screw engaging portion <NUM> can be securely engaged with each other.

Since the first screw member <NUM> and the second screw member <NUM> form the screw assembly <NUM> jointly with the gear case <NUM> and the first bracket <NUM>, the screw assembly <NUM> can be easily assembled to the slider <NUM>.

Another power feeding device <NUM>, which is a modification of the power feeding device <NUM>, is described in the following. The power feeding device <NUM> in the vehicle seat <NUM> allows the wire harness to be paid out according to the position of the slider <NUM> while suppressing unnecessary movement of the wire harness with respect to the floor <NUM>. In a certain embodiment, the wire harness is used for power supply and communication. Further, the power feeding device <NUM> functions as a cover for closing the opening of the rail <NUM>. As shown in <FIG>, the power feeding device <NUM> is provided with a power line <NUM> connected to the power source <NUM> via the control unit <NUM>, a plurality of cover pieces <NUM> attached to the power line <NUM>, and a storage case <NUM> that houses the power line <NUM> and the cover pieces <NUM>. The power line <NUM> is a wire harness whose outer peripheral portion is covered with an electric insulating material. The storage case <NUM> is provided with a storage chamber <NUM> defined therein, an inlet hole <NUM> for communicating the storage chamber <NUM> with the exterior, and a fixing portion <NUM> positioned in the storage chamber <NUM> to fixedly secure an end of the power line <NUM>.

As shown in <FIG>, the storage case <NUM> is formed in a flat box shape. The inlet hole <NUM> of the storage case <NUM> is provided on a side of the storage case <NUM> and is connected to the front end or the rear end of the rail <NUM>. In this embodiment, the inlet hole <NUM> is connected to the rear end of the rail <NUM>. The inlet hole <NUM> is provided at a rear part of the left or right side edge of the storage case <NUM> and opens toward the front. As shown in <FIG>, in the present embodiment, the fixing portion <NUM> is a through hole formed in the bottom wall of the storage case <NUM>. The cover pieces <NUM> are not attached to the one end side of the power line <NUM>, and the power line <NUM> is fixed by being inserted into the fixing portion <NUM>. The power line <NUM> passes through the fixed portion <NUM>, extends to the outside of the storage case <NUM>, and is connected to the control unit <NUM>.

The power line <NUM> passes through the fixed portion <NUM>, the interior of the storage chamber <NUM>, the inlet hole <NUM>, and the rail <NUM> in this order, and is then connected to the electric motor <NUM>. An electric connector connected to the electric motor <NUM> may be provided inside the slider <NUM>, and the power line <NUM> may be connected to this electric connector. The cover pieces <NUM> are connected to the outer peripheral portion of the power line <NUM>. As shown in <FIG>, each cover piece <NUM> includes an upper plate <NUM> and a pair of support pieces <NUM> extending downward from the upper plate <NUM>. The cover pieces <NUM> may be made of, for example, a resin. The support pieces <NUM> interpose the power line <NUM> therebetween. Preferably, a pair of first locking claw <NUM> project from the lower ends of the respective support pieces <NUM> toward each other. The power line <NUM> can be held between the support pieces <NUM> by the first locking claws <NUM> retaining the power line <NUM>.

When one of the cover pieces <NUM> located in the rail <NUM> is considered, the left and right side edges of the upper plate <NUM> thereof are placed on the upper surfaces of the left and right rail upper walls <NUM>, respectively, and the support pieces <NUM> are positioned between the left and right rail inner side walls <NUM>. The lower ends of the support piece <NUM> are provided with second locking claws <NUM> projecting away from each other. The vertical position of the cover piece <NUM> with respect to the rail <NUM> is determined by the abutting of the second locking claws <NUM> against the corresponding rail inner side walls <NUM>. In the present embodiment, the second locking claws <NUM> are in contact with the lower parts of the protrusions <NUM> of the corresponding rail inner side walls <NUM>. In another embodiment, the second locking claws <NUM> abut against the lower edges of the corresponding rail inner side walls <NUM>.

The upper plates <NUM> of the adjacent cover pieces <NUM> have portions that overlap each other when viewed in the vertical direction. The upper plates <NUM> of the adjacent cover pieces <NUM> are rotatably connected to each other via a pivot <NUM> extending vertically so as to be mutually rotatable to each other within a predetermined range. By fitting the cover pieces <NUM> capable of rotating relative to each other within a prescribed range on the power line <NUM>, the deflection of the power line <NUM> is restricted to a predetermined range. One of the cover pieces <NUM> located on the side of the electric motor <NUM> is connected to the rear end of the slider <NUM>. The cover pieces <NUM> cover the part of the rail opening <NUM> of the rail <NUM> located behind the slider <NUM>. Further, the cover pieces <NUM> hide the power line <NUM>.

As shown in <FIG>, the interior of the storage case <NUM> is fitted with a guide wall <NUM> for guiding the moving direction of the cover pieces <NUM>. In this embodiment, the guide wall <NUM> is curved in a semicircular shape in plan view. The guide wall <NUM> smoothly bends the cover piece <NUM> that is moving rearward in the storage chamber <NUM> by making a sliding contact with the side of the cover pieces <NUM>, and guides the cover pieces <NUM> toward the front part of the storage chamber <NUM>.

The upper edge of the inlet hole <NUM> of the storage case <NUM> is located above the upper surface of the rail <NUM>. Further, a side part of the inlet hole <NUM> is provided with a guide slope (not shown in the drawings) for guiding the upper plates <NUM> of the cover pieces <NUM> in the inlet hole <NUM> onto the upper surface of the rail <NUM>.

As shown in <FIG>, when the slider <NUM> moves forward with respect to the rail <NUM>, the power line <NUM> and the cover pieces <NUM> are pulled out forward from the inlet hole <NUM>. At this time, the cover pieces <NUM> are guided by the guide slope with the upper plates <NUM> placed on the rail upper walls <NUM>, and the second locking claws <NUM> located under the lower parts of the corresponding protrusions <NUM>. As a result, the vertical position of the cover pieces <NUM> with respect to the rail <NUM> is positively determined. In this state, each cover piece <NUM> can slide in the fore and aft direction with respect to the rail <NUM>.

As shown in <FIG>, when the slider <NUM> moves rearward with respect to the rail <NUM>, the cover pieces <NUM> are pushed rearward by the slider <NUM>, passe through the inlet hole <NUM>, and are pushed into the storage case <NUM>. Once pushed into the storage case <NUM>, the cover pieces <NUM> are guided by the guide wall <NUM> to the front part of the storage chamber <NUM>.

The present invention has been described in terms of specific embodiments, but is not limited by such embodiments, and can be modified in various ways. For instance, the electrically powered slide rail <NUM> may be provided on an object so that the rail <NUM> extends in the lateral direction or the vertical direction. The shapes of the rail <NUM> and the slider <NUM> can be appropriately changed according to the purpose. In the foregoing embodiments, the present invention was applied to a seat for a vehicle, but the seat for a vehicle according to the present invention can also be applied to various other seats for aircraft, railways, and the like.

Further, the drive gear 43A may be provided both in the front and rear parts. In such case, the first gear 38B and the second gear 39B may be provided both in the front and rear parts so as to correspond to the two drive gears 43A.

In addition to or alternatively to the electric motor <NUM>, the contact terminals <NUM> may be connected to other electrical devices provided on the vehicle seat <NUM> to supply electric power to such electrical devices.

Further, a plurality of sliders <NUM> may be provided on one rail <NUM> do that a plurality of seat cushions <NUM> may be individually arranged on one rail <NUM>. In such a case, the conductive strips <NUM> may be provided so as to correspond to the different seats.

As shown in <FIG>, the slider <NUM> may have a connecting portion <NUM> projecting upward from the base portion <NUM>. The connecting portion <NUM> is formed in a plate shape having laterally facing surfaces. The slider <NUM> may be connected to the seat cushion <NUM> at the connecting portion <NUM>. In this case, the slider <NUM> is formed by a first piece 12A including the connecting portion <NUM>, the base portion <NUM>, the left slider inner side wall <NUM>, the left slider lower wall <NUM>, and the left slider outer side wall <NUM>, and a second piece 12B including the connecting portion <NUM>, the right slider inner side wall <NUM>, the right slider lower wall <NUM>, and the right slider outer side wall <NUM>. Preferably, the first piece 12A and the second piece 12B jointly form the slider <NUM> by overlapping with each other and fastened to each other at the connecting portions <NUM>.

Claim 1:
An electrically powered slide rail (<NUM>), comprising:
a rail (<NUM>) having a channel-shaped cross section and extending in a fore and aft direction;
a slider (<NUM>) received by the rail (<NUM>) and slidably engaged by the rail (<NUM>);
a screw assembly (<NUM>) including a screw member (<NUM>,<NUM>) supported by the slider (<NUM>) so as to be rotatable around an axial line extending in the fore and aft direction;
an electric motor (<NUM>) supported by the slider (<NUM>) and configured to rotate the screw member (<NUM>,<NUM>); and
a screw engaging portion (<NUM>,<NUM>) formed in the rail (<NUM>) so as to extend in the fore and aft direction and engage the screw member (<NUM>, <NUM>);
wherein the rail (<NUM>) is provided with a first side wall (<NUM>) and a second side wall (<NUM>) opposing each other, and
the screw engaging portion (<NUM>, <NUM>) includes a first screw engaging portion (<NUM>) formed on the first side wall (<NUM>), and a second screw engaging portion (<NUM>) formed on the second side wall (<NUM>);
wherein
the screw member (<NUM>, <NUM>) includes a first screw member (<NUM>) that engages with the first screw engaging portion (<NUM>) and a second screw member (<NUM>) that engages with the second screw engaging portion (<NUM>), the first screw member (<NUM>) and the second screw member (<NUM>) being arranged parallel to each other between the first screw engaging portion (<NUM>) and the second screw engaging portion (<NUM>), and
the first side wall (<NUM>) and the second side wall (<NUM>) are respectively formed with protrusions (<NUM>) that protrude toward each other and extend in the fore and aft direction, and the screw engaging portions (<NUM>, <NUM>) include a plurality of engaging holes (<NUM>) formed in the protrusions (<NUM>) along the fore and aft direction.