Vehicle seat belt device

Abstract

To enhance restraint performance with respect to a lumbar part of an occupant.SOLUTION: In a seat belt device 10 for a vehicle, a slide mechanism 30 has a vertical pair of an upper side slider 40 and a lower side slider 42 coupled to a coupling plate 24 of a buckle unit 20. The upper side slider 40 and the lower side slider 42 are coupled in a relatively rotatable manner to the coupling plate 24 by using a right and left direction as its axial direction. Further, the upper side slider 40 and the lower side slider 42 slide independently in a front and rear direction when motors 60L, 60U are driven by a control unit 80. Consequently, a position and an orientation of the buckle unit 20 can be changed according to a seating position (posture) of an occupant P. In other words, a front and rear position of a lap belt 12B and a pressing direction of the lap belt 12B relative to an occupant P can be changed according to a seating position (posture) of the occupant P. Thus, the restraint performance with respect to a lumbar part of an occupant P can be enhanced.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vehicle seat belt device.

Background Art

[0002] In the seat belt attachment mechanism described in Patent Document 1 below, a support plate extends downward from the buckle, and the lower end of the support plate is screwed onto a feed screw connected to a motor. And, before the tongue plate engages with the buckle, the buckle is disposed laterally at the front of the seat cushion. When the tongue plate engages with the buckle, the feed screw rotates by driving the motor, and the buckle moves rearward. As a result, when the occupant engages the tongue plate with the buckle, there is no need to twist the upper body, so the convenience for the occupant can be improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above seat belt attachment mechanism has room for improvement in the following points. That is, in the above seat belt attachment mechanism, as described above, in the state where the tongue plate is engaged with the buckle, the buckle is fixed at the position where it has moved rearward, and the lap belt of the seat belt (the part that restrains the occupant's waist in the seat belt) restrains the occupant's waist.

[0005] On the one hand, when a vehicle undergoes a frontal collision, the inertial force causes the occupant's waist to move forward. At this time, for example, depending on the occupant's seating posture and the like, a so-called submarining phenomenon may occur where the occupant's waist slips under the lap belt. Therefore, in a vehicle seat belt device, it is desirable to have a configuration that can increase the restraint on the occupant's waist and suppress the occurrence of the submarining phenomenon.

[0006] In view of the above facts, an object of the present invention is to provide a vehicle seat belt device capable of increasing the restraint on the occupant's waist.

Means for Solving the Problems

[0007] One or more embodiments of the present invention include a webbing worn by an occupant sitting on a seat cushion of a vehicle seat, a tongue through which the webbing is inserted, a buckle provided outside the seat width direction of the seat cushion and engaged with the tongue, a connecting portion extending downward from the buckle to the lower side of the seat, a pair of upper and lower sliders connected to the connecting portion and configured to be slidable in the front-rear direction of the seat, and a pair of driving portions for sliding the pair of sliders respectively, and a slide mechanism configured to include them, and a control portion for independently driving and controlling the pair of driving portions. The pair of sliders are connected to the connecting portion so as to be relatively rotatable about the seat width direction as the axial direction, and when the pair of driving portions are driven by the control portion, it is a vehicle seat belt device in which the pair of sliders slide independently.

[0008] One or more embodiments of the present invention are provided with a seating detection portion for detecting the seating position of the occupant in the front-rear direction of the seat cushion, and the control portion detects the seating position of the occupant based on the detection signal from the seating detection portion, and drives the driving portion according to the seating position of the occupant to change the position of the slider, which is a vehicle seat belt device.

[0009] One or more embodiments of the present invention provide a vehicle seat belt device, wherein when the control unit detects that an occupant is sitting at the rear part of the seat cushion, the control unit drives the pair of drive units to arrange the slider on the lower side of the seat behind the slider on the upper side of the seat; and when the control unit detects that the occupant is sitting at the front part of the seat cushion, the control unit drives the pair of drive units to align the positions of the pair of sliders in the front-rear direction of the seat.

[0010] One or more embodiments of the present invention provide a vehicle seat belt device, wherein the slide mechanism has rails for supporting the pair of sliders, and the rails include an upper rail portion for slidably supporting the upper slider and a lower rail portion for slidably supporting the lower slider.

[0011] One or more embodiments of the present invention provide a vehicle seat belt device, wherein the rails are provided with racks, and the drive units are configured as motors having pinions meshed with the racks on output shafts, and the motors are respectively provided on the pair of sliders.

Advantages of the Invention

[0012] According to one or more embodiments of the present invention, the restraint on the occupant's waist can be enhanced.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiment for Carrying Out the Invention

[0014] Hereinafter, the vehicle seat belt device 10 according to the present embodiment will be described with reference to the drawings. The vehicle seat belt device 10 is configured as a so-called three-point seat belt device that restrains the waist and upper body of the occupant P sitting on the vehicle seat 90 (automobile). In the present embodiment, the vehicle seat 90 is configured as a rear seat on the right side of the vehicle. Note that the vehicle seat 90 may be a driver's seat or a passenger seat that is a front seat of the vehicle. Further, the arrows FR, UP, and LH appropriately shown in the drawings indicate the front side, upper side, and left side (one side in the seat width direction) of the vehicle seat 90, and the front side, upper side, and left side of the seat coincide with the front side, upper side, and left side of the vehicle. In the following description, when directions such as up and down, front and back, and left and right are used for explanation, unless otherwise specified, they indicate the seat up and down direction, seat front and back direction, and seat left and right direction.

[0015] As shown in FIGS. 1 and 2, the vehicle seat 90 includes a seat cushion 92 that supports the buttocks of the occupant P and a seat back 94 that supports the back of the occupant P. The seat cushion 92 is disposed above the floor panel (not shown) of the vehicle and is fixed to the floor panel. The seat back 94 is disposed in an upright state above the rear end portion of the seat cushion 92.

[0016] (Regarding the vehicle seat belt device 10) As shown in FIGS. 1 to 4, the vehicle seat belt device 10 includes a webbing 12, a buckle unit 20, a slide mechanism 30, a seating sensor 70 as a seating detection unit, and a control unit 80. Hereinafter, each component of the vehicle seat belt device 10 will be described.

[0017] (Regarding the webbing 12) The webbing 12 is formed in a substantially long strip shape. One end of the webbing 12 is connected to the winding shaft of a retractor (not shown) provided in the seat back 94, and the webbing 12 extends from the retractor. The webbing 12 extending from the retractor extends outside the seat back 94 from the right end at the upper end of the seat back 94. Specifically, the webbing 12 extends forward from the seat back 94. The other end of the webbing 12 is connected to an anchor plate 14 disposed on the right side of the seat cushion 92, and the anchor plate 14 is fixed to the floor panel of the vehicle.

[0018] The webbing 12 is provided with a tongue plate 16 as a tongue, and the tongue plate 16 is configured to be relatively movable in the longitudinal direction of the webbing 12. Specifically, the tongue plate 16 has an insertion hole, and the webbing 12 is inserted through the insertion hole. The tongue plate 16 is configured to be engageable with a buckle 22 described later, and the buckle 22 is disposed on the left side of the seat cushion 92. Then, when the webbing 12 is worn on the occupant P, the tongue plate 16 is engaged with the buckle 22. In the state where the webbing 12 is worn on the occupant P, a portion of the webbing 12 on the one end side of the tongue plate 16 is configured as a shoulder belt 12A, and a portion of the webbing 12 on the other end side of the tongue plate 16 is configured as a lap belt 12B. And the shoulder belt 12A extends obliquely in front of the upper body of the occupant P and mainly restrains the right shoulder and chest of the occupant P, and the lap belt 12B extends in the left-right direction in front of the waist of the occupant P to restrain the waist of the occupant P.

[0019] (Regarding the buckle unit 20) The buckle unit 20 extends in the vertical direction, is disposed on the left side of the seat cushion 92, and is connected to the vehicle floor panel via a slide mechanism 30 described later. The buckle unit 20 includes a buckle 22 that constitutes the upper end portion of the buckle unit 20, and a connection plate 24 as a connecting portion extending downward from the buckle 22.

[0020] The buckle 22 is formed in a substantially rectangular flat shape with the left-right direction as the thickness direction, and the vertical position of the buckle 22 is set so that the upper end portion of the buckle 22 is located above the seat cushion 92. An upper-open tongue insertion hole (not shown) is formed in the upper end portion of the buckle 22. By inserting the tongue plate 16 into the tongue insertion hole, the tongue plate 16 engages with an engagement mechanism (not shown) provided in the buckle 22. The buckle 22 is provided with an engagement release portion 22A, and the engagement release portion 22A is exposed to the left from the buckle 22 so as to be pressable. When the engagement release portion 22A is pressed, the engagement state between the buckle 22 and the tongue plate 16 is released.

[0021] The connection plate 24 is formed in a substantially rectangular plate shape with the left-right direction as the plate thickness direction and the vertical direction as the longitudinal direction, and extends downward from the buckle 22. The connection plate 24 is provided with a pair of upper and lower connection shafts 26L and 26U (see FIG. 4). The connection shafts 26L and 26U are formed in a substantially cylindrical shape with the left-right direction as the axial direction, and protrude to the left from the connection plate 24. The pair of connection shafts 26L and 26U are arranged at a predetermined interval in the vertical direction. One connection shaft 26L is arranged at the lower end portion of the connection plate 24, and the other connection shaft 26U is arranged at the upper end side portion of the connection plate 24.

[0022] (Regarding the slide mechanism 30) As shown in FIGS. 3 and 4, the slide mechanism 30 includes a rail 32, an upper slider 40 and a lower slider 42 as a pair of upper and lower sliders, and a movement mechanism 50.

[0023] (Regarding Rail 32) Rail 32 is composed of a pair of left and right rail units 33L and 33R. The pair of rail units 33L and 33R are symmetrically configured. Therefore, hereinafter, the rail unit 33L arranged on the left side will be described, and the description of the rail unit 33R arranged on the right side will be omitted as appropriate.

[0024] The rail unit 33L includes a rail member 34 and a plurality of bearings 36. The rail member 34 is formed in a substantially long plate shape extending in the front-rear direction with the left-right direction as the plate thickness direction. The rail member 34 includes an upper rail portion 34A constituting the upper end portion of the rail member 34, a rail main body portion 34B constituting the middle portion in the vertical direction of the rail member 34, and a lower rail portion 34C constituting the lower end portion of the rail member 34. The rail main body portion 34B is formed in a substantially U-shaped open to the right when viewed from the front. The upper rail portion 34A is formed in a substantially inverted J-shaped open downward when viewed from the front, and the lower end portion of the upper rail portion 34A is connected to the upper end portion of the rail main body portion 34B. The lower rail portion 34C is formed in a shape obtained by inverting the upper rail portion 34A vertically when viewed from the front, and the upper end portion of the lower rail portion 34C is connected to the lower end portion of the rail main body portion 34B. Then, the upper rail portion 34A in the rail member 34 of the rail unit 33L and the upper rail portion 34A in the rail member 34 of the rail unit 33R are joined to each other, and the lower rail portion 34C in the rail member 34 of the rail unit 33L and the lower rail portion 34C in the rail member 34 of the rail unit 33R are joined to each other to form the rail 32. Further, the rail 32 is connected to the vehicle floor panel via a bracket 35 (see FIG. 2) and is arranged in a spaced state above the vehicle floor panel.

[0025] A plurality of bearings 36 are respectively provided on the upper rail portion 34A and the lower rail portion 34C of the rail member 34. Specifically, the plurality of bearings 36 are arranged on the left side of the upper rail portion 34A and the lower rail portion 34C, and are arranged at a predetermined interval in the front-rear direction. The bearing 36 is formed in a substantially cylindrical shape with the left-right direction as the axial direction, and the bearing 36 is supported by a support shaft 38 with the left-right direction as the axial direction. The support shaft 38 is fixed to the upper rail portion 34A and the lower rail portion 34C, and protrudes leftward from the upper rail portion 34A and the lower rail portion 34C. The outer peripheral portion of the bearing 36 provided on the upper rail portion 34A protrudes above the rail member 34, and the outer peripheral portion of the bearing 36 provided on the lower rail portion 34C protrudes above the tip of the lower rail portion 34C.

[0026] (Regarding the upper slider 40) The upper slider 40 is formed in a substantially C-shaped plate shape that is open downward when viewed from the front. Specifically, the upper slider 40 includes a first base wall 40A that extends in the left-right direction with the up-down direction as the plate thickness direction, a pair of side walls 40B that extend downward from both ends in the left-right direction of the first base wall 40A, and a pair of second base walls 40C that extend inward in the left-right direction from the lower ends of the side walls 40B. In addition, inner walls 40D that extend upward are respectively provided at the tip ends of the second base walls 40C. And the upper slider 40 is slidably mounted on the upper rail portion 34A so as to cover the upper rail portion 34A of the rail 32. Specifically, the side walls 40B are arranged outside the bearing 36 in the left-right direction, and the first base wall 40A and the second base wall 40C sandwich the bearing 36 in the up-down direction, so that the upper slider 40 is mounted on the upper rail portion 34A. In addition, the inner wall 40D is arranged inside the upper rail portion 34A. On the lower surface of the first base wall 40A, a pair of left-right slide grooves 40E are formed, and the slide grooves 40E are formed in a substantially inverted V shape that is open downward when viewed from the front. And the outer peripheral portion of the bearing 36 is inserted into the slide grooves 40E. Thereby, the upper slider 40 is slidably connected to the upper end portion of the rail 32 in the front-rear direction.

[0027] On the right side wall 40B of the upper slider 40, a connecting hole 40F is formed to penetrate therethrough. The connecting hole 40F is formed in a long hole shape with the vertical direction as the longitudinal direction. In the connecting hole 40F, the upper connecting shaft 26U in the buckle unit 20 is inserted so as to be relatively rotatable. Specifically, the connecting shaft 26U is configured to be relatively movable in the longitudinal direction of the connecting hole 40F and engageable with the inner peripheral surface of the connecting hole 40F in the left-right direction. Thereby, the upper slider 40 and the upper end side portion of the connecting plate 24 are connected.

[0028] (Regarding the lower slider 42) The lower slider 42 is configured in the same manner as the upper slider 40 turned upside down in the vertical direction. That is, the lower slider 42 includes a first base wall 42A extending in the left-right direction with the vertical direction as the plate thickness direction, a pair of side walls 42B extending upward from both ends in the left-right direction of the first base wall 42A, a pair of second base walls 42C extending inward in the left-right direction from the upper end portions of the side walls 42B, and inner walls 42D extending downward from the tip portions of the second base walls 42C. And, similar to the upper slider 40, the lower slider 42 is slidably mounted on the lower rail portion 34C of the rail 32. Further, in the lower slider 42, slide grooves 42E are respectively formed on the lower surface of the second base wall 42C, and the outer peripheral portions of the lower bearings 36 are inserted into the slide grooves 42E. Thereby, the lower slider 42 is slidably connected to the lower end portion of the rail 32 in the front-rear direction.

[0029] On the right side wall 42B of the lower slider 42, a circular connecting hole 42F is formed to penetrate therethrough. And, in the connecting hole 42F, the lower connecting shaft 26L in the buckle unit 20 is inserted so as to be relatively rotatable. Thereby, the lower slider 42 and the lower end portion of the connecting plate 24 are connected.

[0030] Also, although details will be described later, the lower slider 42 is configured as a member for determining the front-rear position of the buckle unit 20, and the upper slider 40 is configured as a member for determining the orientation (posture) of the buckle unit 20 when viewed from the left-right direction. Further, in the initial positions of the upper slider 40 and the lower slider 42 (the positions shown in FIG. 3), the upper slider 40 and the lower slider 42 are disposed at the rear end portion of the rail 32. Furthermore, in the initial positions of the upper slider 40 and the lower slider 42, the upper slider 40 is disposed at a position shifted forward with respect to the lower slider 42. As a result, the buckle unit 20 is tilted forward so as to incline forward as it goes upward in side view.

[0031] (Regarding the moving mechanism 50) The moving mechanism 50 includes a rack member 52, upper and lower pairs of motors 60L and 60U as driving portions, and upper and lower pairs of position detection portions 54L and 54U (see FIG. 3).

[0032] The rack member 52 is formed in a substantially rectangular column shape extending in the front-rear direction. The rack member 52 is disposed adjacent to the left side of the left rail main body portion 34B of the rail 32 and is fixed to the rail main body portion 34B. A rack 52A is formed at the left end portion of the rack member 52. The rack 52A is composed of a plurality of rack teeth arranged in the front-rear direction and is formed over the entire front-rear direction of the rack member 52.

[0033] The upper and lower pairs of motors 60L and 60U are non-relative movably attached to the upper slider 40 and the lower slider 42 via brackets (not shown). The upper and lower pairs of motors 60L and 60U are configured symmetrically. Therefore, hereinafter, the motor 60U attached to the upper slider 40 will be described, and the description of the motor 60L attached to the lower slider 42 will be omitted as appropriate.

[0034] The motor 60U is arranged with the vertical direction as the axial direction, and the output shaft 62 of the motor 60U extends downward from the motor body 61 of the motor 60U. A pinion 64 is provided integrally rotatably at the tip of the output shaft 62, and a plurality of gear teeth are formed on the outer peripheral portion of the pinion 64. And the pinion 64 is arranged on the left side of the rack member 52 and meshed with the upper part of the rack 52A. Thereby, when the upper motor 60U is driven, the upper slider 40 slides in the front-rear direction, and when the lower motor 60L is driven, the lower slider 42 slides in the front-rear direction. Specifically, when the motors 60L and 60U rotate forward, the upper slider 40 and the lower slider 42 slide forward, and when the motors 60L and 60U rotate reversely, the upper slider 40 and the lower slider 42 slide backward.

[0035] The pair of upper and lower position detection parts 54L and 54U are constituted by a microswitch or the like, fixed to the rear end part of the rail 32, and electrically connected to a control part 80 described later. The upper position detection part 54U is pressed by the upper slider 40 in the initial position, and the lower position detection part 54L is pressed by the lower slider 42 in the initial position, and the position detection parts 54L and 54U are configured to output an on signal to the control part 80.

[0036] (Regarding the seating sensor 70) As shown in FIG. 3, the seating sensor 70 is constituted by a sheet-like pressure sensor or the like. The seating sensor 70 is provided at the upper end part of the seat cushion 92 and covered from above by the skin of the seat cushion 92. The seating sensor 70 is arranged at the front part, the middle part in the front-rear direction, and the rear part of the seat cushion 92 respectively. The seating sensor 70 is electrically connected to the control part 80 and outputs a detection signal based on the pressure change acting on the seating sensor 70 to the control part 80.

[0037] (Regarding the control part 80) The control unit 80 is electrically connected to the pair of motors 60L and 60U, the seating sensor 70, and the position detection units 54L and 54U described above. The control unit 80 is configured to detect the seating position of the occupant P with respect to the seat cushion 92 in the front-rear direction based on the detection signal from the seating sensor 70. Specifically, the control unit 80 is configured to detect the position of the waist of the occupant P. That is, in a state where the occupant P is seated on the seat cushion 92, the weight of the upper body of the occupant P acts on the seat cushion 92 mainly from below the waist (i.e., the buttocks). Therefore, the control unit 80 detects the position of the waist of the occupant P in the front-rear direction from the pressure distribution acting on the seat cushion 92 based on the detection signal from the seating sensor 70. Further, the control unit 80 detects the initial positions of the upper slider 40 and the lower slider 42 based on the output signals of the position detection units 54L and 54U.

[0038] Furthermore, the control unit 80 has a rotation speed measurement unit that measures the rotation speeds of the motors 60L and 60U. When the rotation of the motors 60L and 60U is started at the initial positions of the upper slider 40 and the lower slider 42, the control unit 80 detects the front-rear positions of the upper slider 40 and the lower slider 42 based on the rotation speeds of the motors 60L and 60U measured by the rotation speed measurement unit. And the control unit 80 is configured to control the motors 60L and 60U based on the seating position of the occupant P with respect to the seat cushion 92 in the front-rear direction.

[0039] In addition, a collision detection sensor 82 as a collision detection unit is electrically connected to the control unit 80. The collision detection sensor 82 is composed of an acceleration sensor, a stereo camera, or the like. The acceleration sensor is provided at the front end of the vehicle and configured as a sensor for detecting the acceleration of the vehicle. The stereo camera is provided at the upper end of the vehicle windshield and configured as a sensor for photographing the surroundings of the vehicle. And the control unit 80 is configured to detect a collision of the vehicle (including prediction of a collision of the vehicle) based on the output signal from the collision detection sensor 82. Further, when the control unit 80 detects a collision of the vehicle, it servo-locks the motors 60L and 60U so that the output shafts 62 of the motors 60L and 60U do not rotate, and locks the output shafts 62.

[0040] (Function and effect) Next, the operation and effects of the present embodiment will be described.

[0041] In the initial state of the vehicle seat belt device 10 configured as described above, the upper slider 40 and the lower slider 42 are arranged at the initial positions. As a result, as shown in FIG. 2, the buckle unit 20 is arranged on the left side of the rear part of the seat cushion 92 and is inclined forward as it goes upward when viewed from the left side.

[0042] When the occupant P sits on the seat cushion 92, the occupant P pulls out the webbing 12 forward from the upper end of the seat back 94 and engages the tongue plate 16 with the buckle 22. As a result, the shoulder belt 12A is arranged on the front side of the upper body of the occupant P, and the lap belt 12B is arranged on the front side of the waist of the occupant P.

[0043] When the occupant P sits on the seat cushion 92, the control unit 80 detects the position of the occupant P's waist in the front-rear direction based on the detection signal from the seating sensor 70. When the control unit 80 determines that the position of the occupant P's waist is located above the rear part of the seat cushion 92 (the seating posture of the occupant P shown in FIG. 2, hereinafter referred to as this posture as the normal seating posture), the control unit 80 does not drive the motors 60L and 60U and maintains the state in which the upper slider 40 and the lower slider 42 are arranged at the initial positions. Thereby, the lap belt 12B restrains the occupant P's waist by pressing it downward and rearward.

[0044] On the other hand, when the control unit 80 determines that the position of the occupant P's waist is located above the middle part in the front-rear direction of the seat cushion 92, the control unit 80 rotates the motors 60L and 60U forward to slide the upper slider 40 and the lower slider 42 forward from the initial positions. Specifically, as shown in FIG. 5, the control unit 80 calculates the moving amounts of the upper slider 40 and the lower slider 42 from the rotation speeds of the motors 60L and 60U measured by the rotation speed measurement unit, and arranges the upper slider 40 and the lower slider 42 at the middle part in the front-rear direction of the rail 32. Thereby, when the occupant P's waist is displaced forward with respect to the normal seating posture, the buckle 22 is arranged at the position displaced forward corresponding to this displacement. At this time, the motors 60L and 60U are driven so that the front-rear positions of the upper slider 40 coincide with the front-rear positions of the lower slider 42. Thereby, the buckle unit 20 is arranged so as to extend in the vertical direction, and the lap belt 12B restrains the occupant P's waist by pressing it downward in a side view.

[0045] Furthermore, when the control unit 80 determines that the position of the occupant P's waist is located above the front part of the seat cushion 92, the control unit 80 rotates the motors 60L and 60U forward as described above to slide the upper slider 40 and the lower slider 42 forward from the initial position. Specifically, as shown by the dashed two-dot line in FIG. 5, the control unit 80 calculates the movement amounts of the upper slider 40 and the lower slider 42 from the rotation speeds of the motors 60L and 60U measured by the rotation speed measurement unit, and arranges the upper slider 40 and the lower slider 42 at the front end of the rail 32. Thereby, when the waist of the occupant P is further displaced forward relative to the normal sitting posture, the buckle 22 is arranged at a position displaced forward corresponding to this displacement. At this time, the motors 60L and 60U are driven so that the front-rear position of the upper slider 40 coincides with the front-rear position of the lower slider 42. Thereby, the buckle unit 20 is arranged so as to extend in the vertical direction, and the lap belt 12B restrains the waist of the occupant P by pressing it downward in a side view.

[0046] When the control unit 80 detects a collision of the vehicle based on the output signal from the collision detection sensor 82, the control unit 80 performs servo lock control on the motors 60L and 60U to prevent the rotation of the output shafts 62 of the motors 60L and 60U. Thereby, when the waist of the occupant P is arranged at the rear part of the seat cushion 92, the forward tilt posture of the buckle unit 20 is maintained, and the lap belt 12B restrains the waist of the occupant P by pulling it obliquely downward to the rear. Therefore, the displacement of the waist of the occupant P forward can be suppressed by the lap belt 12B, and the waist of the occupant P can be prevented from slipping under the lap belt 12B. When the waist of the occupant P is arranged at the middle or front part in the front-rear direction of the seat cushion 92, the buckle unit 20 is maintained in an upright posture. Therefore, when the waist is displaced forward from the normal sitting posture, the buckle 22 is arranged at a position displaced forward, and the waist of the occupant P in the displaced state can be restrained by the lap belt 12B so as to be pushed downward.

[0047] In addition, when the control unit 80 detects the getting-off of the occupant P based on the detection signal from the seating sensor 70, the motors 60L and 60U are reversed to slide the upper slider 40 and the lower slider 42 to their initial positions. As a result, the vehicle seat belt device 10 returns to its initial state.

[0048] As described above, according to the vehicle seat belt device 10 of the present embodiment, the slide mechanism 30 has a pair of upper and lower sliders 40 and 42 connected to the connection plate 24 of the buckle unit 20. The upper slider 40 and the lower slider 42 are connected to the connection plate 24 so as to be relatively rotatable about the left-right direction as the axial direction. Then, by driving the motors 60L and 60U by the control unit 80, the upper slider 40 and the lower slider 42 slide independently in the front-rear direction. As a result, as described above, the position and orientation of the buckle unit 20 can be changed according to the seating position (posture) of the occupant P. That is, according to the seating position (posture) of the occupant P, the front-rear position of the lap belt 12B and the pressing direction of the lap belt 12B against the occupant P can be changed. Therefore, the restraint on the waist of the occupant P can be increased.

[0049] Further, the seat cushion 92 is provided with a seating sensor 70 that detects the seating position of the occupant P in the front-rear direction. The control unit 80 detects the seating position of the occupant P based on the detection signal from the seating sensor 70, and drives the motors 60L and 60U to change the positions of the upper slider 40 and the lower slider 42 according to the seating position of the occupant P. Specifically, when the occupant P is seated at the rear part of the seat cushion 92, the buckle unit 20 is arranged on the side of the rear part of the seat cushion 92, and when the occupant P is seated at the front part of the seat cushion 92, the buckle unit 20 is arranged on the side of the front part of the seat cushion 92. As a result, according to the seating position of the occupant P, the buckle 22 can be arranged on the side of the waist of the occupant P, and the lap belt 12B can be properly wound around the waist of the occupant P. Therefore, the restraint on the waist of the occupant P can be further increased.

[0050] When the control unit 80 detects that the occupant P is sitting on the rear part of the seat cushion 92, the control unit 80 drives the pair of motors 60L and 60U so that the lower slider 42 is disposed behind the upper slider 40. That is, the state in which the upper slider 40 and the lower slider 42 are arranged at the initial positions is maintained. When the control unit 80 detects that the occupant P is sitting on the front part of the seat cushion 92, the control unit 80 drives the pair of motors 60L and 60U so that the front-rear positions of the lower slider 42 and the upper slider 40 coincide with each other. Thereby, at the time of a frontal collision of the vehicle, the waist of the occupant P can be favorably restrained by the lap belt 12B, and it is possible to suppress the waist from slipping under the lap belt 12B.

[0051] That is, in the normal sitting posture of the occupant P, the upper body of the occupant P is in a posture of standing up with the waist as the starting point. For this reason, by disposing the lower slider 42 behind the upper slider 40 and restraining the waist of the occupant P by the lap belt 12B so as to pull it obliquely downward to the rear, it is possible to favorably suppress the movement of the waist to the front side. On the other hand, when the waist is displaced forward from the normal sitting posture, the inclination angle of the upper body of the occupant P with respect to the horizontal direction becomes smaller than that in the normal sitting posture. For this reason, it is possible to suppress the movement of the waist to the front side rather than restraining the waist of the occupant P by the lap belt 12B so as to pull it obliquely downward to the rear, but rather restraining the waist downward. As described above, at the time of a frontal collision of the vehicle, the waist of the occupant P can be favorably restrained by the lap belt 12B, and it is possible to suppress the waist from slipping under the lap belt 12B.

[0052] Further, the slide mechanism 30 has a rail 32 that supports the upper slider 40 and the lower slider 42. The rail 32 has an upper rail portion 34A that slidably supports the upper slider 40 and a lower rail portion 34C that slidably supports the lower slider 42. Thereby, the rail 32 can be configured as a common member that supports the upper slider 40 and the lower slider 42. Therefore, compared with a configuration in which members for supporting the upper slider 40 and the lower slider 42 are provided separately in the slide mechanism 30, the number of parts of the slide mechanism 30 can be reduced, contributing to cost reduction.

[0053] In the present embodiment, the control unit 80 drives and controls the motors 60L and 60U based on the detection signal from the seating sensor 70. However, the method of driving and controlling the control unit 80 is not limited to this. For example, an operation button for driving the motors 60L and 60U may be provided in the vehicle, and the control unit 80 may drive the motors 60L and 60U according to the operation of the operation button by the occupant P to change the positions of the upper slider 40 and the lower slider 42. That is, the front-rear position and orientation of the buckle 22 may be changed according to the operation of the occupant P. In this case, for example, the driving amounts of the motors 60L and 60U may be configured to be preset for each occupant.

[0054] Also, in the present embodiment, in the initial positions of the upper slider 40 and the lower slider 42, the upper slider 40 and the lower slider 42 are arranged at the rear end portion of the rail 32. However, the initial positions of the upper slider 40 and the lower slider 42 can be arbitrarily set. For example, the initial positions of the upper slider 40 and the lower slider 42 can be set at the front end portion. In this case, when the occupant P engages the tongue plate 16 with the buckle 22, it is not necessary for the occupant P to twist the upper body, so the convenience for the occupant P can be improved. In this case, a switch for detecting the engagement of the tongue plate 16 with the buckle 22 may be provided on the buckle 22. Thereby, after the tongue plate 16 is engaged with the buckle 22, the buckle 22 can be moved in the front-rear direction according to the seating position of the seated occupant.

[0055] Also, the motors 60L and 60U in the present embodiment may be configured as stepping motors. In this case, the position detection units 54L and 54U in the moving mechanism 50 may be omitted.

Explanation of Reference Numerals

[0056] 10 Vehicle seat belt device 12 Webbing 16 Tongue plate (tongue) 22 Buckle 24 Connecting plate (connecting portion) 30 Slide mechanism 32 Rail 34A Upper rail portion 34C Lower rail portion 40 Upper slider (slider) 42 Lower slider (slider) 52A Rack 60L Motor (drive unit) 60U Motor (drive unit) 62 Output shaft 64 Pinion 70 Occupant sensor (occupancy detection unit) 80 Control unit 90 Vehicle seat 92 Seat cushion P Occupant

Claims

1. A webbing worn by an occupant sitting on a seat cushion of a vehicle seat, a tongue through which the webbing is inserted, a buckle provided on the outer side in the seat width direction of the seat cushion and engaged with the tongue, a connecting portion extending downward from the buckle below the seat, a pair of upper and lower sliders connected to the connecting portion and configured to be slidable in the seat front-rear direction, and a pair of drive portions for sliding the pair of sliders respectively, a slide mechanism configured to include, a control unit for independently driving and controlling the pair of drive portions, comprising, the pair of sliders are connected to the connecting portion so as to be relatively rotatable about the seat width direction as an axial direction, a vehicle seat belt device in which the pair of sliders slide independently by driving the pair of drive portions by the control unit.

2. The seat cushion is provided with a seating detection unit for detecting the seating position of the occupant in the seat front-rear direction, The control unit detects the seating position of the occupant based on a detection signal from the seating detection unit, and drives the drive portion according to the seating position of the occupant to change the position of the slider. The vehicle seat belt device according to claim 1.

3. When the control unit detects that the occupant is sitting on the rear portion of the seat cushion, the control unit drives the pair of drive portions so that the slider on the lower side of the seat is disposed on the rear side of the seat than the slider on the upper side of the seat, When the control unit detects that the occupant is sitting on the front portion of the seat cushion, the control unit drives the pair of drive portions so that the positions of the pair of sliders in the seat front-rear direction coincide with each other. The vehicle seat belt device according to claim 2.

4. The slide mechanism has a rail for supporting the pair of sliders, The rail has an upper rail portion for slidably supporting the upper slider and a lower rail portion for slidably supporting the lower slider. The vehicle seat belt device according to any one of claims 1 to 3.

5. A rack is provided on the rail, The drive portion is configured as a motor having a pinion meshed with the rack on an output shaft, The vehicle seat belt device according to claim 4, wherein the motor is provided on each of the pair of sliders.

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