JP2006036119A - Webbing winding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a webbing winding device capable of reliably supporting an occupant body when a vehicle is overturned. <P>SOLUTION: In the state in which a pawl 72 is engaged with a ratchet wheel 70, and the rotation of the ratchet wheel 70 in the drawing direction is regulated, the rotation of a spool 20 in the drawing direction is regulated, the drawing of a webbing belt 22 is regulated, and the rotation in the drawing direction of an end 24B of a torsion shaft 24 as a connection end of the torsion shaft 24 to the spool 20 is regulated. In this condition, the rotational force in the drawing direction applied to the spool 20 is not transmitted to the torsion shaft 24, and no torsion is generated in the torsion shaft 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a webbing retractor constituting a seat belt device for restraining the body of an occupant seated on a seat of a vehicle or the like with a long belt-like webbing belt.

  A seat belt device that restrains the body of an occupant seated in a vehicle seat with a long belt-like webbing belt includes a webbing take-up device that is fixed to the vehicle body on the side of the seat. The webbing take-up device includes, for example, a spool (winding shaft) whose axial direction is substantially along the vehicle front-rear direction, and the longitudinal base end side of the webbing belt is locked to the spool. The spool can wind the webbing belt around the outer periphery of the spool, and when the seat belt device is not used, the spool is wound around the outer periphery of the spool.

Moreover, the webbing take-up device disclosed in Patent Document 1 below includes a motor. When an abnormality in vehicle behavior is detected, such as when the vehicle rolls over, that is, in a so-called "rollover" state, the motor output shaft and the spool are connected to transmit the motor driving force to the spool and forcefully Rotate the spool in the winding direction. By forcibly rotating the spool in the winding direction in this way, the body of the occupant wearing the webbing belt is restrained by a relatively strong restraining force, and thus the occupant can be held.
JP 2002-104135 A

  Incidentally, the webbing take-up device is provided with a so-called “force limiter mechanism”. The force limiter mechanism includes a rod-like torsion shaft. The torsion shaft is disposed inside the cylindrical spool, and the axial direction is parallel to the axial direction of the spool. The torsion shaft is integrally connected to the spool at one axial end, and basically the torsion shaft rotates integrally with the spool.

  On the other hand, a so-called “lock mechanism” is provided on the other axial end side of the torsion shaft. When the vehicle suddenly decelerates, the lock mechanism engages the pawl provided on the other axial end of the torsion shaft with the ratchet formed on the frame of the webbing take-up device, and rotates the torsion shaft. It has a structure to regulate.

  That is, in the webbing take-up device provided with the force limiter mechanism and the lock mechanism described above, the lock mechanism restricts the rotation of the torsion shaft in the pull-out direction at the other axial end when the vehicle suddenly decelerates. To do.

  As described above, since the torsion shaft is connected to the spool at one end in the axial direction, the rotation of the torsion shaft in the pull-out direction is restricted, so that the rotation of the spool in the pull-out direction is indirectly restricted. The As a result, the withdrawal of the webbing belt is restricted, and the occupant's body can be reliably restrained by the webbing belt.

  Next, the occupant's body pulls the webbing belt when the occupant's body attempts to move inertially toward the front side of the vehicle during sudden deceleration of the vehicle. When the rotational force in the pull-out direction of the spool based on this tensile force exceeds the mechanical strength of the torsion shaft, the axial end of the torsion shaft (that is, the connecting portion with the spool) has the other end (that is, the lock mechanism). Rotate in the pull-out direction with respect to the portion subjected to the rotation restriction by), and the torsion shaft is twisted and deformed.

  In this way, the torsion shaft is twisted and deformed, so that the spool can rotate in the pull-out direction, the webbing belt can be pulled out, and the webbing belt absorbs a part of the force that holds the occupant's body.

  Here, in the above-described rollover state of the vehicle or just before the rollover, the occupant's body can be securely held by the webbing belt so that the occupant's body does not fall even if the vehicle is upside down. preferable.

  However, if the torsion shaft cannot support the weight of the occupant even if the webbing belt is wound with the driving force of a motor or the like and the force to restrain the occupant's body is strengthened, the torsion shaft is twisted and deformed, Thereby, there is a possibility that the webbing belt is pulled out.

  In view of the above fact, an object of the present invention is to provide a webbing retractor that can reliably support the occupant's body when the vehicle rolls over.

  In the webbing take-up device according to the first aspect of the present invention, the base end side in the longitudinal direction of the long belt-like webbing belt is locked, and the webbing belt is rotated around the axis in one winding direction to rotate the webbing belt around the outer periphery. And pulling out the webbing belt to the distal end side and pulling out the webbing belt to detect a spool that rotates in a pull-out direction opposite to the winding direction, and the posture of the vehicle, and Attitude detection means for outputting an attitude detection signal when the attitude of the vehicle is tilted by a certain angle or more, and when the attitude detection signal is output from the attitude detection means, the rotation of the spool in the pull-out direction is restricted. And a locking mechanism.

  According to the webbing take-up device according to the first aspect of the present invention, the longitudinal base end side of the webbing belt is locked to the spool, and when the spool is rotated in the take-up direction which is one of the axes around the spool. The webbing belt is wound around the outer peripheral portion of the spool in a layered manner from the base end side, whereby the webbing belt is stored.

  On the other hand, when the webbing belt is pulled toward the leading end in such a winding state, the spool rotates in the drawing direction opposite to the winding direction while the webbing belt wound around the spool is pulled out. The webbing belt pulled out in this way is hung on the body of an occupant seated in the seat, for example, and the tongue plate provided in the middle part in the longitudinal direction of the webbing belt is engaged with the buckle device provided on the side of the seat As a result, the webbing belt is attached to the occupant's body, and the occupant's body is restrained by the webbing belt.

  With such a webbing belt attached, when the vehicle is tilted by a predetermined angle or more around an axis with the vehicle longitudinal direction as the axial direction and is in a so-called “rollover” or just before rollover, the posture detection means A detection signal is output. As described above, when the posture detection signal is output from the posture detection means, the lock mechanism is activated, and the rotation of the spool is restricted by the lock mechanism. By restricting the rotation of the spool in this way, the withdrawal of the webbing belt in the rollover state or the state immediately before rollover is restricted, and the vehicle occupant can be reliably held by the webbing belt in the rollover state or just before the rollover.

  A webbing take-up device according to a second aspect of the present invention is the webbing retractor according to the first aspect of the present invention, wherein the webbing take-up device is mechanically coupled to the spool and the pulling direction is partially restricted in displacement. Energy absorbing means that deforms by being displaced in conjunction with the rotation of the spool to the lock, and the locking mechanism restricts the displacement and deformation of the energy absorbing means that is interlocked with the rotation of the spool in the pull-out direction. The rotation of the spool is regulated.

  In the webbing take-up device according to the second aspect of the present invention, the energy absorbing means is mechanically connected to the spool. For example, when the vehicle occupant's body is about to move inertially toward the front side of the vehicle when the vehicle suddenly decelerates, the webbing belt attached to the occupant's body is pulled.

  When the webbing belt is pulled, the spool tries to rotate in the pulling direction, and when the spool further rotates in the pulling direction, the energy absorbing means connected to the spool is displaced.

  However, if the energy absorbing means is partially restricted in such a state, the energy absorbing means tries to restrict the rotation of the spool in the pull-out direction. In such a state, when the rotational force applied to the spool in the pulling direction exceeds the mechanical strength of the energy absorbing means, the energy absorbing means is deformed and is displaced in conjunction with the rotation of the spool in the pulling direction. .

  In this way, the spool is allowed to rotate in the pull-out direction, and the energy absorbing means is deformed during the rotation of the spool in the pull-out direction, so that the body of the occupant wearing the webbing belt can be prevented. The holding force applied by the webbing belt is absorbed.

  On the other hand, in the webbing take-up device according to the present invention, when a posture detection signal is output from the posture detection means when the vehicle is tilted by a predetermined angle or more around an axis in which the vehicle longitudinal direction is substantially the axial direction, Displacement and deformation of the energy absorbing means in conjunction with the rotation of the spool to the are restricted by the lock mechanism.

  Thereby, the rotation in the pull-out direction of the spool that is allowed by the displacement and deformation of the energy absorbing means is indirectly restricted, and the webbing belt withdrawing in the rollover state or the state immediately before the rollover is reliably restricted. For this reason, the vehicle occupant can be reliably held by the webbing belt in the rollover state or just before the rollover.

  A webbing take-up device according to a third aspect of the present invention is the webbing take-up device according to the second aspect of the present invention, wherein the axial direction is coaxial with the spool and is arranged inside the spool formed in a cylindrical shape. The torsion shaft that is integrally connected to the spool on the other end side than the one end portion in the axial direction and that locks the one end portion in the axial direction in the vehicle sudden deceleration state is used as the energy absorbing means, and the locking mechanism Is characterized in that the rotation of the torsion shaft is restricted at the other end side in the axial direction from the connecting portion of the torsion shaft to the spool.

  According to the webbing take-up device according to the third aspect of the present invention, the spool is formed in a cylindrical shape, and a torsion shaft as energy absorbing means is disposed coaxially with the spool inside the spool. The

  The torsion shaft is integrally connected to the spool on the other end side with respect to the one end portion in the axial direction. When the spool rotates, the torsion shaft rotates together with the spool. However, when the vehicle suddenly decelerates, one end of the torsion shaft is locked in the axial direction, thereby restricting rotation of the torsion shaft at one end in the axial direction.

  As described above, when the vehicle suddenly decelerates, the vehicle occupant's body is about to move inertially toward the front of the vehicle, and the occupant's body pulls the webbing belt, which causes the spool to rotate in the pull-out direction. The connecting portion with the spool tends to rotate in the pull-out direction together with the spool.

  In this state, when the rotational force applied to the spool in the pull-out direction exceeds the mechanical strength of the torsion shaft, the torsion shaft is twisted by rotating the connecting portion with the spool in the pull-out direction relative to one axial end. As a result, the torsion shaft is deformed.

  Thus, the spool rotates in the pull-out direction by the amount of twist of the torsion shaft. For this reason, the webbing belt is pulled out by the amount of rotation of the spool, and the holding force applied by the webbing belt to the body of the occupant wearing the webbing belt is absorbed by the torsion shaft being twisted and deformed.

  On the other hand, in the webbing take-up device according to the present invention, when a posture detection signal is output from the posture detection means when the vehicle is tilted by a predetermined angle or more around an axis whose axial direction is substantially the vehicle longitudinal direction, the torsion shaft The other end in the axial direction is locked by the lock mechanism with respect to the connecting portion with the spool.

  As described above, the rotational force of the spool that attempts to rotate in the pull-out direction is transmitted to the torsion shaft through the connecting portion between the spool and the torsion shaft, and the connecting portion between the spool of the torsion shaft and the spool is rotated in the pull-out direction. To do.

  Therefore, the other end side in the axial direction is locked relative to the connecting portion with the spool of the torsion shaft, so that the rotation of the connecting portion with the spool of the torsion shaft in the pull-out direction is restricted. The rotation of the connecting portion of the torsion shaft with respect to the portion to the spool is restricted, and the above-described twist (that is, deformation of the torsion shaft) does not occur.

  Thereby, the rotation in the pull-out direction of the spool that is allowed by the twist of the torsion shaft is indirectly restricted, and the withdrawal of the webbing belt in the rollover state or the state immediately before the rollover is reliably restricted. For this reason, the vehicle occupant can be reliably held by the webbing belt in the rollover state or just before the rollover.

  A webbing take-up device according to a fourth aspect of the present invention includes a substantially cylindrical spool in which a longitudinal base end side of a long belt-like webbing belt is locked to an outer peripheral portion, and the spool is arranged around its axis. By rotating in one winding direction, the webbing belt is wound around the outer periphery of the spool from the base end side, and by pulling the webbing belt to the tip side, the direction opposite to the winding direction is obtained. A webbing take-up device that pulls out the webbing belt while rotating the spool in the pull-out direction, and is mechanically connected to the spool and partially displaced in the spool in the pull-out direction. The energy absorbing means which is deformed by being displaced in conjunction with the rotation of the first and the second lock while restricting partial displacement of the energy absorbing means in the first locked state. In this state, the rotation of the spool in the pull-out direction is restricted while the transmission of the rotational force of the spool in the pull-out direction to the energy absorbing means is blocked, and the first lock state and the second lock state can be switched. And a locking means.

  According to the webbing take-up device of the present invention as set forth in claim 4, when the longitudinal base end side of the webbing belt is locked to the spool, and the spool is rotated in the take-up direction which is one of the axes around the spool. The webbing belt is wound around the outer peripheral portion of the spool in a layered manner from the base end side, whereby the webbing belt is stored.

  On the other hand, when the webbing belt is pulled toward the leading end in such a winding state, the spool rotates in the drawing direction opposite to the winding direction while the webbing belt wound around the spool is pulled out. The webbing belt pulled out in this way is hung on the body of an occupant seated in the seat, for example, and the tongue plate provided in the middle part in the longitudinal direction of the webbing belt is engaged with the buckle device provided on the side of the seat As a result, the webbing belt is attached to the occupant's body, and the occupant's body is restrained by the webbing belt.

  On the other hand, in the webbing take-up device according to the present invention, the energy absorbing means is mechanically connected to the spool. For example, when the vehicle occupant's body is about to move inertially toward the front side of the vehicle when the vehicle suddenly decelerates, the webbing belt attached to the occupant's body is pulled.

  When the webbing belt is pulled, the spool tries to rotate in the pulling direction, and when the spool further rotates in the pulling direction, the energy absorbing means connected to the spool is displaced.

  In such a state, when the locking means is activated to enter the first locked state, the energy absorbing means is partially restricted by the locking means. When the energy absorbing means is partially restricted in this manner, the energy absorbing means tries to restrict the rotation of the spool in the drawing direction.

  Further, when the rotational force applied to the spool in the pulling direction exceeds the mechanical strength of the energy absorbing means, the energy absorbing means is deformed and displaced in conjunction with the rotation of the spool in the pulling direction.

  In this way, the spool is allowed to rotate in the pull-out direction, and the energy absorbing means is deformed during the rotation of the spool in the pull-out direction, so that the body of the occupant wearing the webbing belt can be prevented. The holding force applied by the webbing belt is absorbed.

  By the way, the lock means is in a second lock state different from the first lock state described above, and can regulate the rotation of the spool. In the second locked state, even if the spool tries to rotate in the pull-out direction, transmission of the rotational force from the spool to the energy absorbing means is interrupted.

  Therefore, the spool is not displaced or deformed in the second locked state. For this reason, in the first lock state, the spool can rotate in the pull-out direction at least by the amount of displacement and deformation of the energy absorbing means, but in the second lock state, the spool cannot rotate in the pull-out direction.

  Thereby, for example, the pulling-out of the webbing belt is reliably regulated by setting the lock means to the second lock state in the state of the vehicle rollover or immediately before rollover. For this reason, the vehicle occupant can be reliably held by the webbing belt in the rollover state or just before the rollover.

  A webbing retractor according to a fifth aspect of the present invention is the webbing retractor according to the fourth aspect of the present invention, wherein the posture of the vehicle is detected and a predetermined level is detected when the posture of the vehicle is tilted by a predetermined angle or more. An attitude detection means for outputting a signal is provided, and the lock means switches to the second lock state when the detection signal of the predetermined level is outputted from the attitude detection means.

  According to the webbing take-up device of the present invention as set forth in claim 5, the vehicle is tilted by a predetermined angle or more around an axis whose axial direction is substantially the vehicle longitudinal direction, so-called "rollover" or a state immediately before rollover. Then, a posture detection signal is output from the posture detection means. As described above, when the posture detection signal is output from the posture detection unit, the lock unit is activated.

  Here, as described above, when the posture detection signal is output, the lock unit is in the second lock state. As described above, unlike the first locked state, the second locked state cannot rotate the spool in the pull-out direction.

  For this reason, the pulling-out of the webbing belt in the rollover state of the vehicle or just before the rollover is reliably restricted, and the vehicle occupant can be reliably held by the webbing belt in the rollover state or just before the rollover.

  As described above, the webbing retractor according to the present invention can reliably prevent the spool from rotating in the pull-out direction when the vehicle rolls over. Therefore, the webbing belt is not pulled out when the vehicle rolls over, and the occupant's body can be securely held by the webbing belt.

[Configuration of this embodiment]
FIG. 1 is a front sectional view schematically showing the overall configuration of a webbing take-up device 10 according to an embodiment of the present invention.

  As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 includes a flat back plate 14, and the back plate 14 is fixed to the vehicle body by fastening means (not shown) such as bolts, whereby the webbing take-up device 10 is attached to the vehicle body.

  A pair of leg plates 16 and 18 extend in parallel with each other from both ends in the width direction of the back plate 14. A substantially cylindrical spool 20 is disposed between the leg plates 16 and 18.

  The spool 20 has an axial direction opposite to the leg plates 16 and 18 and is rotatable around its own axis. Further, the longitudinal base end portion of the long belt-like webbing belt 22 is locked to the spool 20.

  The webbing belt 22 is wound around the outer peripheral portion of the spool 20 in the form of a layer from the base end side and stored by rotating the spool 20 in a winding direction around one of its axes. Further, when the webbing belt 22 is pulled from the front end side, the webbing belt 22 wound around the spool 20 is pulled out, and accordingly, the spool 20 rotates in a pulling direction opposite to the winding direction.

  Further, a torsion shaft 24 as an energy absorbing means is provided coaxially with the spool 20 inside the spool 20. Further, a fitting hole 26 is formed at an end portion on the leg plate 16 side along the axial direction of the spool 20. The fitting hole 26 has a substantially circular cross-sectional shape that is substantially coaxial with the spool 20, and the fitting hole 26 has a stepped shape in which the inner diameter dimension gradually increases toward one end in the axial direction.

  On the other hand, a locking device 30 constituting locking means is provided on one axial end side of the spool 20. The lock device 30 includes a lock base 32. The lock base 32 includes a fitting portion 34.

  The fitting portion 34 is formed in a substantially columnar shape corresponding to the inner peripheral shape of the fitting hole 26, and the outer dimension is gradually reduced toward the other axial end side (leg plate 18 side) of the spool 20. The fitting portion 34 is fitted into the fitting hole 26 so as to be coaxially rotatable relative to the spool 20 inside the fitting hole 26, and the end portion 24A of the torsion shaft 24 on the leg plate 16 side is coaxial and They are connected together.

  The locking device 30 includes a case 36. The case 36 is provided outside the leg plate 16 (that is, opposite to the leg plate 18), and is fixed to the leg plate 16 integrally with the leg plate 16 by fastening means such as screws or fitting means such as fitting claws. ing. Inside the case 36 are members such as a ratchet gear and a compression coil spring (not shown) that constitute the locking device 30, and a spiral spring that urges the lock base 32 directly or indirectly in the winding direction. Has been.

  The ratchet gear in the case 36 is pivotally supported by the lock base 32 so as to be coaxial with and relative to the spool 20 and the lock base 32. One end of the compression coil spring in the case 36 is locked to the ratchet gear, and the other end is locked to the lock base 32.

  When the biasing force of the compression coil spring is increased by rotating or locking the compression coil spring by rotating the lock base 32, the compression coil spring biases the ratchet gear in the rotation direction of the lock base 32 by the biasing force. The ratchet gear is configured to rotate following the lock base 32.

  Further, the ratchet gear is engaged with a lock plate 38 attached to the lock base 32, and the ratchet gear cannot follow the lock base 32 that is about to rotate in the pull-out direction (that is, the ratchet gear is locked). When rotating in the winding direction relative to the base 32), the lock plate 38 is guided by the ratchet gear and moves outward in the rotational radial direction of the spool 20, and the internal teeth formed on the leg plate 16 The ratchet teeth 40 are engaged. Accordingly, the rotation of the lock base 32 and consequently the spool 20 in the pull-out direction is restricted.

  Further, an acceleration sensor for the locking device 30 (not shown) is arranged below the ratchet gear in the radial direction. The acceleration sensor includes an engaging claw that can move toward and away from the ratchet gear, a steel ball provided on the opposite side of the engaging claw to the ratchet gear, and a substantially dish-shaped mounting on which the steel ball is placed. And a mounting portion.

  The acceleration sensor for the lock device 30 engages the engaging claw with the ratchet gear when the steel ball rolls on the mounting portion in the vehicle suddenly decelerating state and the steel ball pushes up the engaging claw to move closer to the ratchet gear. To regulate the rotation of the ratchet gear.

  As described above, the ratchet gear rotates following the lock base 32 by the urging force of the compression coil spring. However, when the rotation of the ratchet gear is restricted by the engagement claw of the acceleration sensor engaging the ratchet gear, the ratchet Relative rotation occurs between the gear and the lock base 32. Thereby, the lock plate 38 meshes with the ratchet teeth 40 as described above.

  On the other hand, a sleeve 42 is provided at the end 24B of the torsion shaft 24 on the leg plate 18 side. The sleeve 42 is formed in a bottomed cylindrical shape that opens toward the leg plate 16, and the end 24 </ b> B of the torsion shaft 24 enters the inside thereof so that the torsion shaft 24 and the sleeve 42 are coaxially and integrally connected. Has been.

  A circular hole 44 is formed in the spool 20 corresponding to the sleeve 42. The sleeve 42 is fitted into the circular hole 44 and is coaxially and integrally connected to the spool 20.

  A shaft portion 46 extends coaxially with respect to the torsion shaft 24 and the spool 20 from the end surface of the sleeve 42 opposite to the torsion shaft 24. The shaft portion 46 passes through a circular hole 48 formed in the leg plate 18 and protrudes outside the leg plate 18.

  In addition, a lock mechanism 50 that constitutes a lock means together with the lock device 30 is provided outside the leg plate 18. The lock mechanism 50 includes an external gear 52. As shown in FIG. 2, the gear 52 is pivotally supported on the shaft portion 46 so as to be relatively rotatable coaxially with the shaft portion 46.

  Further, a solenoid 54 is provided on the outer side of the gear 52 in the rotational radius direction (below the gear 52 in FIG. 2). The solenoid 54 includes a coil whose axial direction is set in the rotational tangent direction of the gear 52. The solenoid 54 is electrically connected to the battery 58 via a driver 56.

  The driver 56 is electrically connected to the ECU 60, and the drive control signal S output from the ECU 60 is input to the driver 56. Based on the input drive control signal S, the driver 56 passes a current through the coil of the solenoid 54 or interrupts the current flowing through the coil.

  The ECU 60 is electrically connected to a rollover sensor 62 as posture detecting means. The rollover sensor 62 includes a gyro and the like, and detects the posture of the vehicle, for example, the inclination angle of the vehicle around an axis whose axial direction is the vehicle longitudinal direction or the vehicle lateral direction.

  The rollover sensor 62 outputs a posture detection signal at a level corresponding to the vehicle posture. The attitude detection signal output from the rollover sensor 62 is input to the ECU 60, and the ECU 60 determines the attitude state of the vehicle based on the input attitude detection signal.

  On the other hand, the solenoid 54 is provided with a plunger 64. The longitudinal direction (axial direction) of the plunger 64 is along the rotational tangent direction of the gear 52, and the base end side enters the inside of the solenoid 54. At least the base end side in the longitudinal direction of the plunger 64 is formed of a ferromagnetic material such as iron. When the coil in the solenoid 54 is energized and a magnetic field is formed around the coil, the plunger 64 is placed inside the solenoid 54. Aspirated and slides.

  A rack bar 66 is formed at the tip of the plunger 64, and external teeth formed on the side surface of the rack bar 66 mesh with the gear 52. Accordingly, when the plunger 64 moves to the inside of the solenoid 54, the rack bar 66 rotates the gear 52 by a certain angle.

  Further, a return spring 68 is provided between the rack bar 66 and the solenoid 54, and the plunger 64 is urged through the rack bar 66 in a direction protruding from the solenoid 54.

  On the other hand, as shown in FIGS. 1 and 2, a ratchet wheel 70 is formed coaxially and integrally with the shaft portion 46 between the leg plate 18 and the gear 52. As shown in FIG. 2, a pawl 72 is disposed on the outer side in the rotational radial direction of the ratchet wheel 70.

  The pawl 72 is formed in a substantially plate shape having a thickness direction along the opposing direction of the leg plate 18 and the gear 52. A pin 74 protrudes from the end surface of the pawl 72 on the leg plate 18 side in the thickness direction. The pin 74 is rotatably supported by a bearing hole 76 formed in the leg plate 16.

  A pin 78 projects from the end surface of the pawl 72 on the gear 52 side in the thickness direction. The pin 78 is provided eccentrically with respect to the pin 74, and enters the guide hole 80 formed in the gear 52. The guide hole 80 is a slit-like hole whose width direction is slightly larger than the outer diameter dimension of the pin 78, and the other end is located on the center side of the gear 52 with respect to one end in the longitudinal direction.

  By being pressed by the inner periphery of the guide hole 80, the pin 78 moves between one end and the other end of the guide hole 80 as shown in FIG. 3. As described above, since the pin 74 of the pawl 72 has entered the bearing hole 76, the pawl 72 rotates around the pin 74 when the pin 78 moves in the guide hole 80.

  Further, as shown in FIG. 2, external teeth 82 are formed on a part of the outer periphery of the pawl 72. The external teeth 82 are formed so as to be able to mesh with ratchet teeth formed on the outer peripheral portion of the ratchet wheel 70. When the pawl 72 rotates around the pin 74 so that the pin 78 moves to the center side of the gear 52, the external teeth 82 mesh with the ratchet wheel 70. In the meshed state between the pawl 72 and the ratchet wheel 70, the pawl 72 restricts the rotation of the ratchet wheel 70 in the pull-out direction.

[Operation and effect of the present embodiment]
Next, the operation and effect of the present embodiment will be described through the operation of the webbing take-up device 10.

<Basic operation of webbing take-up device 10>
First, the basic operation of the webbing take-up device 10 will be described.

  In the webbing take-up device 10, when the webbing belt 22 is wound around the spool 20 while the webbing belt 22 is wound in layers, when the webbing belt 22 is pulled while pulling a tongue plate (not shown), the webbing belt 22 wound around the spool 20 is pulled. Pulled out.

  The tongue plate provided at the middle in the longitudinal direction of the webbing belt 22 is inserted into a buckle device (all not shown) while the webbing belt 22 pulled out in this way is hung around the front of the body of the occupant seated in the seat. By holding the tongue plate on the buckle device, the webbing belt 22 is attached to the occupant's body (hereinafter simply referred to as “attached state”).

  Further, a spiral spring housed in the case 36 is directly or indirectly connected to the lock base 32. For this reason, when the webbing belt 22 is pulled out to mount the webbing belt 22 and the lock base 32 is rotated in the pull-out direction via the spool 20, the sleeve 42 and the torsion shaft 24, the spiral spring is tightened.

  When the spiral spring is tightened in this manner, the biasing force of the spiral spring increases, and the spool 20 is biased toward the winding direction via the lock base 32, the torsion shaft 24, and the sleeve 42.

  Thus, in the above-mentioned wearing state, since the spiral spring urges the webbing belt 22 to be wound around the spool 20, the webbing belt 22 is fitted to the occupant's body, and the webbing belt 22 restrains and holds the occupant's body. To do.

  On the other hand, when the holding of the tongue plate by the buckle device is released and the tongue plate comes out of the buckle device, the force for maintaining the webbing belt 22 while being pulled out is released against the biasing force of the spiral spring. Thereby, the spool 20 rotates in the winding direction by the urging force of the spiral spring. By the rotation of the spool 20 in the winding direction, the pulled-out webbing belt 22 is wound in layers on the outer periphery of the spool 20 from the base end side, and the webbing belt 22 is stored.

<Operation and effect of locking means>
By the way, the webbing take-up device 10 is provided with the lock means constituted by the lock device 30 and the lock mechanism 50 as described above, and the rotation of the spool is locked by the lock means.

  Here, there are two modes of the locking of the spool 20 by the locking means of the webbing take-up device 10: a “first locked state” and a “second locked state”.

  First, the first locked state will be described.

(First locked state)
When the vehicle is suddenly decelerated in the above-mentioned wearing state, the body of the vehicle occupant tends to inertially move substantially forward of the vehicle. As a result, the webbing belt 22 attached to the occupant's body is pulled rapidly. When the webbing belt 22 is pulled suddenly, the spool 20 suddenly rotates in the pulling-out direction. The rotation of the spool 20 is transmitted to the lock base 32 via the sleeve 42 and the torsion shaft 24, and the lock base 32 is rotated in the pull-out direction.

  As described above, the ratchet gear of the lock device 30 rotates following the rotation of the lock base 32 by the urging force of the compression coil spring, but the lock base 32 suddenly rotates in the pull-out direction. The ratchet gear cannot rotate following the lock base 32, and a relative rotation occurs between the ratchet gear and the lock base 32.

  Even if the vehicle is in a state where it can follow and rotate, the steel ball constituting the acceleration sensor for the lock device 30 rolls on the mounting portion due to inertia when the vehicle suddenly decelerates, and the engaging claw Push up. Thereby, an engaging claw engages with a ratchet gear and regulates rotation of the ratchet gear in the pull-out direction.

  As described above, the rotation of the ratchet gear is restricted by the engaging claw, so that a relative rotation is generated between the lock base 32 and the ratchet gear that are about to rotate in the pull-out direction.

  Thus, when the lock base 32 rotates relative to the ratchet gear, the lock plate 38 is guided by the ratchet gear and moves outward in the rotational radial direction of the spool 20, so It meshes with the ratchet teeth 40 of the teeth. When the lock plate 38 meshes with the ratchet teeth 40, the lock plate 38, the lock base 32, the torsion shaft 24, and the spool 20 are locked, and the rotation of the spool 20 in the pull-out direction is restricted.

  By restricting the rotation of the spool 20 in the pull-out direction, the withdrawal of the webbing belt 22 from the spool 20 is restricted. Therefore, even if the webbing belt 22 is pulled by the body of the occupant who is about to move inertially forward in the vehicle sudden deceleration state, the webbing belt 22 is not pulled out and the webbing belt 22 attached to the body of the occupant. The occupant's body can be securely held by.

  Next, in a state where the above-described locking device 30 is activated, when the occupant's body, which is about to move inertially toward the front side of the vehicle, pulls the webbing belt 22 with a greater force, a greater rotational force in the pull-out direction is applied to the spool 20. Is granted. The spool 20 is integrally connected to the torsion shaft 24 via a sleeve 42. For this reason, the rotational force in the pull-out direction applied to the spool 20 is applied to the end 24 </ b> B of the torsion shaft 24.

  On the other hand, as described above, the rotation of the lock base 32 in the pull-out direction is restricted by the lock plate 38 meshing with the ratchet teeth 40, and therefore, the end portion of the torsion shaft 24 fixed to the lock base 32. 24A does not rotate, and as a result, the entire torsion shaft 24 does not rotate in the pull-out direction.

  Here, when the rotational force in the pull-out direction applied to the end portion on the leg plate 18 side of the torsion shaft 24 via the spool 20 and the sleeve 42 exceeds the mechanical strength of the torsion shaft 24, the end portion of the torsion shaft 24 The torsion shaft 24 is deformed by twisting so that 24B rotates relative to the end 24A in the pull-out direction.

  In this way, the torsion shaft 24 is twisted and deformed so that the end 24B rotates in the pull-out direction, so that the spool 20 can rotate in the pull-out direction by the amount of twist, and if the torsion shaft 24 breaks, the spool 20 Can be rotated in the pull-out direction. In this way, by allowing the spool 20 to rotate in the pull-out direction, the restraining force in a state where the body of the occupant is restrained by the webbing belt 22 is prevented from exceeding a certain value.

(Second locked state)
On the other hand, in the webbing retractor 10, the ECU 60 that controls the solenoid 54 of the lock mechanism 50 is connected to the rollover sensor 62. As described above, the rollover sensor 62 detects the inclination angle of the vehicle around an axis whose axial direction is the vehicle longitudinal direction or the vehicle lateral direction.

  Therefore, as shown in the time chart of FIG. 4, during the traveling of the vehicle, the posture detection signal at a level corresponding to the posture of the vehicle (for example, the inclination angle of the vehicle around the axis with the vehicle longitudinal direction as the axial direction). E is output from the rollover sensor 62.

  As shown in the state after the elapsed time T1 in the time chart of FIG. 4, when the vehicle is tilted, the value of the posture detection signal E increases as the tilt angle increases. Further, as shown in the state of the elapsed time T2, the vehicle tilts to a predetermined angle, and the attitude detection signal E with the signal level Er is output from the rollover sensor 62, and the attitude detection signal E with the signal level Er. Is input to the ECU 60, the drive control signal S output from the ECU 60 is switched from the Low level to the High level.

  When the high-level drive control signal S output from the ECU 60 is input to the driver 56, the driver 56 starts energizing the coil of the solenoid 54. When a magnetic field is formed around the coil by energizing the coil of the solenoid 54, the plunger 64 is drawn inside the solenoid 54 against the urging force of the return spring 68. As a result, the rack bar 66 rotates the gear 52 clockwise in FIG.

  As the gear 52 rotates in this way, the inner peripheral portion of the guide hole 80 formed in the gear 52 presses the pin 78 and rotates the pawl 72 around the pin 74. Thereby, as shown in FIG. 3, the external teeth 82 of the pawl 72 mesh with the ratchet wheel 70, and the rotation of the ratchet wheel 70 in the pull-out direction is restricted.

  Since the ratchet wheel 70 is formed coaxially and integrally with the shaft portion 46 of the sleeve 42, the rotation of the ratchet wheel 70 in the pull-out direction is restricted, so that the sleeve 42 and eventually the spool 20 are pulled out. Rotation is regulated. As a result, the withdrawal of the webbing belt 22 from the spool 20 is restricted in a state immediately before the vehicle rolls over or in a state where the vehicle rolls over.

  Therefore, even if the occupant's body tries to move away from the seat and the webbing belt 22 is pulled by the occupant when the vehicle rolls over, the webbing belt 22 is not pulled out.

  Here, the sleeve 42 is integrally connected to the spool 20 and the end 24 </ b> B of the torsion shaft 24. Therefore, when the rotation of the ratchet wheel 70 integrated with the sleeve 42 in the pull-out direction is restricted by the pawl 72, the pawl 72 does not go through the torsion shaft 24 but the pawl 72 passes through the sleeve 42 and ends of the spool 20 and the torsion shaft 24. The rotation of the portion 24B in the pull-out direction is restricted (that is, in the second locked state, the rotation of the end portion 24B that is the connecting end of the torsion shaft 24 with the spool 20 is restricted).

  For this reason, even if the locking device 30 operates in this state and the end portion 24A of the torsion shaft 24 is locked, the end portion 24B of the torsion shaft 24 is restricted by the rotation of the end portion 24A. The torsion shaft 24 is not twisted without rotating in the pull-out direction with respect to 24A.

  Therefore, in the second locked state, unlike the first locked state described above, it cannot be said that the spool 20 is allowed to rotate in the pull-out direction due to twisting or breaking of the torsion shaft 24.

  Thereby, in this webbing retractor 10, the webbing belt 22 is not inadvertently pulled out in the above-mentioned rollover state, and the body of the occupant can be reliably held by the webbing belt 22 in the rollover state.

  In the present embodiment, the mode in which the end portion 24B of the sleeve 42 is locked by the lock mechanism 50 is the second locked state. However, the second locked state may be an aspect that can regulate the rotation of the spool 20 without transmitting the rotational force of the spool 20 in the pull-out direction to the torsion shaft 24.

  Therefore, for example, a lock mechanism that mechanically connects the spool 20 to the frame 12 without using the torsion shaft 24 may be provided instead of the lock mechanism 50 described above.

  Furthermore, in the present embodiment, the torsion shaft 24 is used as the energy absorbing means. However, the energy absorbing means is not limited to the torsion shaft 24 as described above, and has a predetermined size in the first locked state. Any structure that allows the spool 20 to rotate in the pull-out direction by deformation (either elastic deformation or plastic deformation) when a rotational force in the pull-out direction equal to or greater than that is applied to the spool 20 may be used.

It is front sectional drawing which shows the outline of a structure of the webbing winding apparatus which concerns on one embodiment of this invention. It is side surface sectional drawing which shows the outline of a structure of the principal part of the webbing retractor which concerns on one embodiment of this invention. It is side surface sectional drawing corresponding to FIG. 2 which shows a mode that the locking mechanism act | operated and was in the 2nd locked state. It is a time chart which shows the relationship between the attitude | position detection signal of an attitude | position detection means, and the drive control signal of ECU.

Explanation of symbols

10 Webbing take-up device 20 Spool 22 Webbing belt 24 Torsion shaft (energy absorption means)
30 Locking device (locking means)
50 Locking mechanism (locking means)
62 Rollover sensor (posture detection means)

Claims (5)

The longitudinal base end side of the belt-like webbing belt is locked, and the webbing belt is wound around the outer periphery from the base end side by rotating in one winding direction around the axis, and the webbing belt is pulled to the front end side. And pulling out the webbing belt to rotate the spool in the pulling direction opposite to the winding direction;
Attitude detection means for detecting an attitude of the vehicle and outputting an attitude detection signal when the attitude of the vehicle is tilted by a certain angle or more;
A lock mechanism that restricts rotation of the spool in the pull-out direction when the posture detection signal is output from the posture detection means;
A webbing take-up device comprising: An energy absorbing means that is mechanically connected to the spool and deforms by being displaced in conjunction with rotation of the spool in the pull-out direction in a state where displacement is partially restricted; Restricting rotation of the spool in the pull-out direction by restricting displacement and deformation of the energy absorbing means in conjunction with rotation of the spool;
The webbing take-up device according to claim 1. The axial direction is coaxial with the spool, and is disposed inside the cylindrical spool, and is integrally connected to the spool at the other end side with respect to one end in the axial direction. The torsion shaft whose one end in the axial direction is locked in the decelerating state is used as the energy absorbing means, and the lock mechanism restricts the rotation of the torsion shaft at the other end in the axial direction from the connecting portion of the torsion shaft to the spool. To
The webbing take-up device according to claim 2. A long belt-like webbing belt has a substantially cylindrical spool whose longitudinal end is locked to the outer peripheral portion, and the spool is rotated in one winding direction around its axis, whereby the outer periphery of the spool The webbing winding is configured to wind the webbing belt from the base end side of the webbing belt, and pulling the webbing belt while pulling the webbing belt to the tip end side to rotate the spool in the pulling direction opposite to the winding direction. A take-off device,
Energy absorbing means mechanically connected to the spool and deformed by being displaced in conjunction with rotation of the spool in the pull-out direction in a state where displacement is partially restricted;
The pulling direction of the spool is controlled while restricting partial displacement of the energy absorbing means in the first locked state and blocking transmission of rotational force in the pulling direction of the spool to the energy absorbing means in the second locked state. Locking means that regulates rotation to the first and second lock states;
A webbing take-up device comprising: When a posture detection unit that detects a vehicle posture and outputs a detection signal of a predetermined level when the vehicle posture is tilted by a certain angle or more, and the detection signal of the predetermined level is output from the posture detection unit The locking means switches to the second locked state,
The webbing take-up device according to claim 4.

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