JP2004237841A - Webbing take-up device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a webbing take-up device capable of disconnecting the mechanical connection of a pretensioner mechanism and a torsion shaft as soon as the rotation of the torsion shaft in a pull-out direction starts after the end of the operation of the pretensioner mechanism. <P>SOLUTION: When the piston 88 is about to be rapidly depressed, a taper part 94 of the piston 88 presses the taper part of the stopper ring 96 to enlarge the diameter of the stopper ring 96 and the outer peripheral part of the stopper ring 96 is brought into press-contact with the inner peripheral part of a cylinder 86. Thus the downward movement of the piston 88 is restricted. Further when the torsion shaft 44 rotates in the pull-out direction in this state, a pin 60 connecting the small diameter cylindrical part 50 and the large diameter part 56 of a sleeve 48 is sheared. As the pretensioner 78 and the torsion shaft 44 are substantially separated, the twisting of the torsion shaft 44 is not affected by the inner pressure of the cylinder 86. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a webbing take-up device that constitutes a seat belt device for restraining an occupant's body sitting on a seat of a vehicle or the like with a long belt-shaped webbing belt.
[0002]
[Prior art]
2. Description of the Related Art A seat belt device that restrains the body of an occupant seated on a vehicle seat with a long belt-shaped webbing belt includes a webbing winding device fixed to a vehicle body at a 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 end of the webbing belt is locked to the spool. The spool can take up the webbing belt around its outer periphery in a layered manner. When the seat belt device is not used, the webbing belt can be wound around and accommodated in the outer periphery of the spool.
[0003]
Further, the webbing take-up device has a lock mechanism that detects acceleration (deceleration) when the vehicle suddenly decelerates and restricts rotation of the spool in the pull-out direction. The pretensioner mechanism for detecting the acceleration (deceleration) of the spool and forcibly rotating the spool in the winding direction, and furthermore, in the locked state of the spool by the lock mechanism described above, the inertia in the vehicle sudden deceleration state causes the vehicle to move forward. A force limiter mechanism or the like is provided to keep the restraining force of the webbing belt when the body of the occupant who moves to the side pulls the webbing belt below a certain value.
[0004]
The lock mechanism generally includes a lock base provided on one end side in the axial direction of the spool. The lock base is disposed coaxially with the spool inside the spool and coaxially and integrally with the other axial end of the torsion shaft integrally connected to the spool at the other axial end of the spool. Are linked.
[0005]
Further, the lock mechanism includes an inert plate (inertia plate) that can rotate relative to the lock base coaxially. However, the inertia plate is connected to the lock base via a compression coil spring or a torsion coil spring.
For this reason, with respect to the rotation of the spool in a normal state, the spool follows the rotation by the urging force of the spring as described above.
[0006]
However, when the spool suddenly rotates in the pulling-out direction, the inertial plate cannot follow the rotation of the spool, and if the relative rotation occurs between the inertial plate and the spool, the rotation is linked to the relative rotation. Then, the lock member meshes with the ratchet teeth of the ratchet hole formed in the frame constituting the webbing take-up device, thereby restricting the rotation of the lock base at one axial end of the spool and indirectly rotating the spool. Is regulated.
[0007]
On the other hand, the force limiter mechanism locks the other end in the axial direction of the torsion shaft integrated with the spool when a rotation force of a predetermined value or more in the pullout direction is further applied to the spool in the locked state by the lock mechanism. The torsion shaft locked by the mechanism is plastically deformed by twisting it in the drawing direction with respect to one axial end, and the webbing belt is allowed to be pulled out by this amount of deformation, so that the restraining force by the webbing belt is more than a certain value. It is configured not to rise.
[0008]
Further, the pretensioner mechanism includes a cylinder whose internal pressure rises due to a gas pressure supplied instantaneously during a rapid deceleration of the vehicle. A piston is slidably housed inside the cylinder, and the piston slides when the internal pressure increases as described above.
[0009]
An intermediate portion in the longitudinal direction of the wire is supported on the piston, or a rack bar is integrally fixed. In the case of a wire, the proximal end of the wire is fixed near the cylinder, and the distal end is wound around a rotary drum coaxially connected to a torsion shaft.
[0010]
The wire tension increased by the sliding of the piston rotates the rotating drum in the winding direction, thereby forcibly applying a rotational force to the spool in the winding direction.
[0011]
On the other hand, in the case of the structure in which the rack bar is fixed to the piston, a pinion is connected to the other end of the torsion shaft, and when the piston slides due to an increase in the internal pressure of the cylinder, the rack bar meshes with the pinion, and the pinion and the pinion This is a structure in which a spool is forcibly rotated in a winding direction via a torsion shaft.
[0012]
By the way, as described above, the force limiter mechanism has a structure in which the torsion shaft is torsionally deformed so that the restraining force by the webbing belt is not increased to a certain value or more. Therefore, basically, the mechanical strength of the torsion shaft is set so that the torsion shaft is torsionally deformed by a predetermined magnitude of rotational force acting on the other end of the torsion shaft.
[0013]
On the other hand, if the pretensioner mechanism is already operating when the force limiter mechanism is operating, the torsion shaft that is about to rotate in the pull-out direction moves the piston in the direction opposite to the sliding direction when the internal pressure of the cylinder increases. To slide. As described above, in this state, since the gas is supplied into the cylinder, the piston slides against the internal pressure in the cylinder. For this reason, the internal pressure of the cylinder becomes a drag force when the one axial end of the torsion shaft is rotated in the pull-out direction.
[0014]
Here, the following patent document discloses an example of a structure that eliminates a drag that hinders rotation of the torsion shaft at one axial end in the pull-out direction.
[0015]
[Patent Document 1]
JP-A-10-226313
[Problems to be solved by the invention]
Briefly describing the features of the structure disclosed in Patent Literature 1, after the operation of the pretensioner mechanism is completed, the shear pin is broken by a rotational force in a direction in which the torsion shaft (torsion bar) is pulled out. This is a structure in which mechanical connection between the tensioner mechanism and the torsion shaft is forcibly canceled, and rotation of the torsion shaft is not transmitted to the pretensioner mechanism side.
[0017]
However, in the case of the structure disclosed in Patent Document 1, the shear pin cannot be broken until the torsion shaft has been rotated in the pulling direction by a fixed amount. Therefore, it takes a little time to forcibly cancel the mechanical connection between the pretensioner mechanism and the torsion shaft, and there is still room for improvement in this respect.
[0018]
In view of the above facts, the present invention provides a webbing winding which can quickly cancel the mechanical connection between the pretensioner mechanism and the torsion shaft after the rotation of the pretensioner mechanism in the drawing direction is started after the operation of the pretensioner mechanism is completed. The purpose is to obtain a take-off device.
[0019]
[Means for Solving the Problems]
The present invention according to claim 1 has a substantially tubular spool in which a longitudinal base end of a long belt-shaped webbing belt is locked to an outer peripheral portion, and rotates the spool in one winding direction around its axis. By rotating the spool, the webbing belt is wound around the outer peripheral portion of the spool from the base end side, and the spool is rotated in the pull-out direction opposite to the winding direction by pulling the webbing belt toward the distal end side. A webbing take-up device that pulls out the webbing belt while causing the webbing belt to be pulled out, the torsion shaft being provided substantially coaxially with the spool inside the spool, and having one axial end integrally connected to the spool, Shaft locking means for locking the other end of the torsion shaft in the axial direction when the vehicle is rapidly decelerating; A pretensioner mechanism that has a cylinder that accommodates the shaft, and a piston that slides by increasing the internal pressure of the cylinder, and rotates a rotating body provided at one axial end of the torsion shaft in the winding direction; The rotating body is connected to one axial end of the torsion shaft to transmit the rotation of the rotating body to the torsion shaft to rotate the torsion shaft in the winding direction, and the relative rotation of the torsion shaft with respect to the rotating body. Connecting means for deforming or breaking the connection to release the connection, and after the completion of the rise of the piston, the rotation of the rotating body in the pull-out direction or the sliding of the piston in a direction opposite to the sliding direction when the internal pressure rises And a pretensioner locking means for restricting sliding and locking the pretensioner mechanism. .
[0020]
According to the webbing take-up device having the above-described configuration, the base end in the longitudinal direction of the webbing belt is locked to the outer peripheral portion of the substantially cylindrical spool, and when the spool is rotated in the take-up direction, which is one of the directions around the axis of the spool. The webbing belt is wound in a layered manner from the base end side on the outer peripheral portion of the spool, whereby the webbing belt is stored.
[0021]
On the other hand, when the webbing belt is pulled toward the distal end in the above winding state, the spool rotates in the pulling direction opposite to the winding direction while the webbing belt wound on the spool is pulled out. The webbing belt pulled out in this manner is wrapped around, for example, the body of an occupant seated on a seat, and a tongue plate provided at a longitudinally intermediate portion of the webbing belt is engaged with a buckle device provided on the side of the seat. By doing so, the webbing belt is attached to the occupant's body, and the occupant's body is restrained by the webbing belt.
[0022]
On the other hand, when the vehicle suddenly decelerates, the internal pressure of the cylinder of the pretensioner mechanism increases, whereby the piston slides. The piston rotates the rotating body due to sliding caused by an increase in the internal pressure of the cylinder, and rotates the torsion shaft connected to the rotating body via the connecting means in the winding direction. Further, the rotation of the torsion shaft in the winding direction forcibly rotates the spool in the winding direction.
[0023]
Thereby, the webbing belt is forcibly wound on the spool. As a result, the restraining force of the webbing belt on the occupant's body increases, and the webbing belt restrains the occupant's body more strongly than before the pretensioner mechanism is activated, and the occupant tries to move to the front side of the vehicle due to the inertia during rapid deceleration of the vehicle. Is securely held by the webbing belt.
[0024]
When the occupant's body pulls the webbing belt due to inertia at the time of rapid deceleration of the vehicle in a state after the operation of the pretensioner mechanism, a rotational force in the pulling direction based on the pulling force at this time is applied to the spool. Further, this rotational force is applied to one axial end of a torsion shaft integrated with the spool.
[0025]
On the other hand, when the vehicle suddenly decelerates, the shaft locking means operates, and the other axial end of the torsion shaft is locked by the shaft locking means. As described above, the other end in the axial direction of the torsion shaft is locked by the shaft locking means, and the one end in the axial direction is applied with the rotational force in the pulling-out direction from the spool, so that the torsion shaft is twisted. Due to the energy absorption caused by the torsion shaft being twisted (that is, deformed), the increase in the restraining force by which the webbing belt corresponding to the pulling force of the occupant pulling the webbing belt restrains the occupant's body is suppressed.
[0026]
Here, as described above, when a rotational force in the pull-out direction is applied to one end of the torsion shaft and the torsion shaft attempts to rotate in the pull-out direction, the rotational force of the torsion shaft is also applied to the rotating body described above. Further, when a rotating force in the pull-out direction in this state is applied to the rotating body, the rotating body tends to slide the piston in the direction opposite to the sliding direction when the internal pressure of the cylinder increases.
[0027]
However, in this webbing take-up device, the rotation of the rotating body in the pulling-out direction or the sliding of the piston in the direction opposite to the sliding direction when the internal pressure of the cylinder increases when the operation of the pretensioner mechanism is completed is performed by the pretensioner locking means. As a result, the pretensioner mechanism is locked. For this reason, when relative rotation occurs between the torsion shaft and the rotating body under such a restriction, the connection between the torsion shaft and the rotating body by the connecting means is released.
[0028]
Thereby, since the pretensioner mechanism is substantially separated from the torsion shaft, the internal pressure of the cylinder does not affect the rotation of the torsion shaft in the pull-out direction. Therefore, there is no need to consider the internal pressure of the cylinder when setting the mechanical strength of the torsion shaft, and the mechanical strength of the torsion shaft can be easily set.
[0029]
In the webbing take-up device, the rotation of the rotating body in the pulling-out direction or the sliding of the piston in the direction opposite to the sliding direction when the internal pressure of the cylinder increases when the operation of the pretensioner mechanism is completed as described above. Since the torsion shaft is regulated by the pretensioner lock means, the relative rotation of the torsion shaft with respect to the rotating body occurs immediately after the torsion shaft starts rotating in the drawing direction. Therefore, immediately after the rotation of the torsion shaft in the drawing direction is started, the mechanical connection between the rotating body and the torsion shaft can be quickly released (eliminated), and the energy absorption by the torsion shaft can be started at an early stage.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
<Configuration of First Embodiment>
FIG. 1 is a front cross-sectional view schematically showing the overall configuration of a webbing take-up device 10 according to a first embodiment of the present invention.
[0031]
As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 is provided with a substantially plate-shaped back plate 14, and the back plate 14 is fixed to the vehicle body by a not-shown fastening means such as a bolt, so that the webbing retractor 10 is attached to the vehicle body. ing. A pair of leg plates 16 and 18 extend parallel to each other from both ends in the width direction of the back plate 14, and a spool 20 manufactured by die casting or the like is rotatably arranged between the leg plates 16 and 18.
[0032]
The spool 20 has a substantially cylindrical spool body 22. Flanges 24 and 26 are formed substantially coaxially with the spool body 22 at both axial ends of the spool body 22. The base end of a long strip-shaped webbing belt 28 is locked to the spool body 22 between the two flange portions 24 and 26. When the spool 20 is rotated to one side around its axis, the webbing belt 28 is wound up in a layered manner from the base end side to the outer peripheral portion of the spool body 22. Further, when the webbing belt 28 is pulled from the front end side, the webbing belt 28 wound around the outer peripheral portion of the spool body 22 is pulled out, and accordingly, the rotation direction when the webbing belt 28 is wound (hereinafter, this direction). Is referred to as a “winding direction” for the sake of convenience (hereinafter, the rotating direction of the spool 20 when the webbing belt 28 is pulled out is referred to as a “drawing direction” for convenience).
[0033]
A fitting hole 30 is formed at one end of the spool body 22 in the axial direction (the leg plate 16 side). The cross-sectional shape of the fitting hole 30 is a substantially circular shape that is substantially coaxial with the spool body 22. In addition, the fitting hole 30 has a cut-out shape in which the inner diameter is gradually increased toward one end in the axial direction.
[0034]
On the other hand, a lock base 32 is provided at one axial end of the spool 20. The lock base 32 has a fitting portion 34. The fitting portion 34 is formed in a substantially cylindrical shape whose outer dimensions gradually decrease toward the other axial end of the spool 20. The fitting portion 34 is fitted into the fitting hole 30, and is locked. A base 32 is coaxially mounted on the spool 20 so as to be relatively rotatable. Further, a lock plate mounting portion 36 is integrally formed on one end side in the axial direction of the fitting portion 34, and a lock plate 40 constituting a lock mechanism 38 as shaft locking means is mounted.
[0035]
The lock mechanism 38 has a case 42. The case 42 is provided outside the leg plate 16 (that is, on the side opposite to the leg plate 18), and is integrally fixed to the leg plate 16 by fastening means such as screws or fitting means such as fitting claws. ing. Inside the case 42, members constituting the lock mechanism 38, such as a ratchet gear and a compression coil spring, not shown, are housed.
[0036]
The above-mentioned ratchet gear is axially supported at one axial end of a torsion shaft 44 to be described later so as to be rotatable coaxially with the spool 20 and the lock base 32. One end of the compression coil spring is locked to the ratchet gear, and the other end is locked to the lock base 32. As a result, when the urging force of the compression coil spring increases due to the rotation of the lock base 32 to compress or pull the compression coil spring, the compression coil spring applies the ratchet gear in the rotation direction of the lock base 32 by the urging force. The lock base 32 is urged to rotate in the same direction as the rotation direction of the ratchet gear.
[0037]
A lock plate 40 attached to the lock base 32 is engaged with the ratchet gear. When the ratchet gear rotates relative to the lock base 32 in the winding direction, the ratchet gear is guided to the ratchet gear. As a result, the spool 20 moves outward in the radial direction of rotation of the spool 20, meshes with the ratchet teeth 46 of the internal teeth formed on the leg plate 16, and regulates the rotation of the lock base 32.
[0038]
Further, an acceleration sensor (not shown) for the lock mechanism 38 is disposed below the ratchet gear in the radial direction. The acceleration sensor includes an engagement claw that can move toward and away from the ratchet gear, a steel ball provided on the opposite side of the engagement claw from the ratchet gear, and a substantially dish-shaped mounting member on which the steel ball is mounted. And a mounting part. When the steel ball rolls on the mounting portion in the vehicle suddenly decelerating state, the steel ball pushes up the engagement claw to move closer to the ratchet gear, and the engagement claw is engaged with the ratchet gear. Thus, the ratchet gear is restricted from rotating.
[0039]
On the other hand, a torsion shaft 44 is housed coaxially with the spool 20 inside the spool body 22. One end of the torsion shaft 44 in the axial direction penetrates the lock base 32 coaxially, rotatably supports the ratchet gear as described above, and is rotatably supported by the case 42.
[0040]
Also, a part of the outer peripheral portion of the portion of the torsion shaft 44 that has entered the lock base 32 is subjected to spline processing, whereby the torsion shaft 44 and the lock base 32 are coaxially and integrally connected. I have.
[0041]
On the other hand, a sleeve 48 as a connecting means is provided on the other axial end of the torsion shaft 44. As shown in FIGS. 1 and 2, the sleeve 48 includes a small-diameter cylindrical portion 50. The small-diameter cylindrical portion 50 has an outer peripheral portion subjected to spline processing. The small-diameter cylindrical portion 50 is fitted into a spline hole 52 coaxial with the spool main body 22 opened at the other axial end of the spool main body 22 so as to be coaxial with the spool main body 22. They are integrally connected. In the small-diameter cylindrical portion 50, a spline hole 54 having an inner peripheral portion subjected to spline processing is formed coaxially with the small-diameter cylindrical portion 50. The other end of the torsion shaft 44 in the axial direction is fitted into the spline hole 54. The other end of the torsion shaft 44 in the axial direction is splined on the outer periphery, whereby the small-diameter cylindrical portion 50 and the torsion shaft 44 are coaxially and integrally connected.
[0042]
A large-diameter portion 56 that forms the sleeve 48 together with the small-diameter cylindrical portion 50 is provided on the other axial side of the small-diameter cylindrical portion 50. The outer diameter of the large diameter portion 56 is substantially circular, and the outer diameter of the large diameter portion 56 is larger than that of the small diameter cylindrical portion 50. A pair of small holes 58 penetrates along the axial direction of the large diameter portion 56 at a position eccentric from the axial center position of the large diameter portion 56. Pins 60 are fitted into these small holes 58, respectively. The pin 60 has an axial dimension longer than the large-diameter portion, and one end in the axial direction projects from the end face of the large-diameter portion 56 at one axial end. Small holes 62 are formed in the small-diameter cylindrical portion 50 corresponding to portions of the pins 60 protruding from the large-diameter portion 56, and each pin 60 is inserted into the small hole 62. Thus, the small-diameter tube portion 50 and the large-diameter portion 56 are mechanically connected to each other with respect to the rotation of the small-diameter tube portion 50 around the axis.
[0043]
As described above, the large-diameter portion 56 connected to the small-diameter tubular portion 50 via the pin 60 penetrates the circular hole 64 formed in the leg plate 18 and projects outside the frame 12.
[0044]
Further, a clutch frame 68 constituting the clutch 66 is provided outside the frame 12. The outer periphery of the clutch frame 68 is formed in a thick disk shape sufficiently larger than the large-diameter portion 56, and is disposed substantially coaxially with the spool 20 so as to face the leg plate 18.
[0045]
The clutch frame 68 is formed with a bottomed hole 70 opened at one end in the axial direction. Therefore, the clutch frame 68 is formed in a shallow bottomed cylindrical shape as a whole. The inner peripheral portion of the bottomed hole 70 is divided at approximately 120 degrees, and each of them is a clutch wall 72. The size of each clutch wall 72 from the axial center position of the clutch frame 68 gradually decreases in the pull-out direction. However, even in a portion where the dimension from the axial center position of the clutch frame 68 is minimum, the dimension from the axial center position of the clutch frame 68 is sufficiently larger than the radial dimension of the large diameter portion 56.
[0046]
Further, a clutch roller 74 is disposed between each clutch wall 72 and the outer peripheral portion of the large diameter portion 56. The clutch roller 74 is formed in a cylindrical shape whose axial direction is substantially the same as the axial center of the spool 20. The outer diameter dimension of each clutch roller 74 is determined by the dimension from the axial position of the clutch frame 68 in the portion of the clutch wall 72 where the dimension from the axial position of the clutch frame 68 is the maximum, and the large diameter portion 56. Is smaller than the radius dimension of the clutch frame 68 but smaller than the radius dimension of the large diameter portion 56 in a portion where the dimension from the axis position of the clutch frame 68 is minimum. Is also large enough. Further, each clutch roller 74 is held by a holding piece 76 locked to the leg plate 18 so as not to be in contact with any of the outer peripheral portion of the large diameter portion 56 and the clutch wall 72.
[0047]
On the other hand, a pinion 80 that constitutes a pretensioner mechanism 78 is formed coaxially on the outer bottom of the clutch frame 68, and a rack bar 82 as a slide member is arranged outward of the pinion 80 in the rotation radial direction. I have.
[0048]
The rack bar 82 has a longitudinal direction substantially along the vertical direction of the frame 12, and has rack teeth 84 intermittently formed at one end in the width direction. Although the rack teeth 84 do not mesh with the pinion 80, the rack bar 82 can mesh with the pinion 80 by sliding upward.
[0049]
On the other hand, the pretensioner mechanism 78 includes a cylinder 86. The cylinder 86 is formed in a substantially bottomed cylindrical shape that opens toward the upper side of the frame 12. A through hole (not shown) is formed in the peripheral wall on the bottom side of the cylinder 86, and a gas generator (not shown) as gas generating means is connected through the through hole.
[0050]
The gas generator is provided with an ignition device, a gas generation unit, and the like.For example, when the ignition device operates when acceleration detection means such as an acceleration sensor detects a sudden deceleration state of the vehicle, the ignition device emits gas from the gas generation unit. The generator is instantaneously burned, and a large amount of gas is instantaneously generated and supplied to the bottom of the cylinder 86.
[0051]
A piston 88 is arranged inside the cylinder 86. The piston 88 includes a pair of disk portions 90 facing each other along the axial direction of the pair of cylinders 86. Further, a small-diameter portion 92 having an outer diameter smaller than that of the disk portion 90 is provided between the disk portions 90, and the outer diameter is gradually reduced downward below the small-diameter portion 92. Is provided with a substantially frusto-conical tapered portion 94 that reduces the diameter of the tapered portion. The disk portion 90, the small diameter portion 92, and the tapered portion 94 are formed integrally coaxially.
[0052]
An O-ring (o-ring) 95 formed in a substantially ring shape from rubber or a synthetic resin material having elasticity comparable to that of rubber is disposed radially outward of the small-diameter portion 92. On the other hand, a stopper ring 96 as a pretensioner locking means is disposed radially outward of the tapered portion 94.
[0053]
As shown in FIG. 3, the stopper ring 96 is generally formed in a substantially ring shape from a metal material having a spring property. Further, the inner peripheral portion of the stopper ring 96 is formed as a tapered portion 98, and is formed so that the inner diameter is gradually reduced downward, and the minimum inner diameter is larger than the maximum outer diameter of the tapered portion 94. It is set to be sufficiently small.
[0054]
The stopper ring 96 is not completely ring-shaped, and a part thereof is cut along the radial direction. Therefore, the stopper ring 96 has one end and the other end along the circumferential direction. The stopper ring 96 is elastically deformed in a direction in which the one end and the other end are separated from each other, so that the inner diameter of the stopper ring 96 and This is a configuration in which the outer diameter dimension increases.
[0055]
On the other hand, as shown in FIG. 1, a shaft 100 is formed coaxially with the spool 20 on the opposite side of the large-diameter portion 56 from the small-diameter cylindrical portion 50. The shaft 100 rotatably supports the clutch frame 68 and the pinion 80 by coaxially penetrating the bottom of the clutch frame 68 and the pinion 80, and a pretensioner frame extending from the upper end of the cylinder 86. 102, and enters a case (not shown) provided on the opposite side to the frame 12 via the pretensioner frame 102.
[0056]
This case (not shown) is fixed to the pretensioner frame 102 or the frame 12 and houses a spiral spring inside. In this spiral spring, the end located relatively outside the spiral is locked to the case, and the end located inside is locked to the shaft 100. When the shaft 100 rotates in the pulling-out direction, Then, the spiral spring is wound and the urging force is increased, and the shaft 100 is urged in the winding direction.
[0057]
<Operation and Effect of First Embodiment>
Next, the operation and effect of the present embodiment will be described through the description of the operation of the webbing take-up device 10.
[0058]
First, the basic operation of the webbing winding device 10 will be described.
[0059]
In the webbing take-up device 10, when the webbing belt 28 is pulled while pulling a tongue plate (not shown) in a housed state in which the webbing belt 28 is wound in a layer on the spool 20, a spiral that urges the spool 20 in the winding direction is provided. The webbing belt 28 is pulled out while rotating the spool 20 in the pulling direction against the urging force of the spring. In this manner, with the webbing belt 28 pulled out, the tongue plate is inserted into the buckle device (not shown) while the webbing belt 28 is wrapped around the body of the occupant sitting on the seat, and the buckle device holds the tongue plate. As a result, the state in which the webbing belt 28 is worn on the occupant's body (hereinafter, simply referred to as “wearing state”) is established.
[0060]
When the webbing belt 28 is pulled out to mount the webbing belt 28 and the spool 20 is rotated in the pulling-out direction, the rotation of the spool 20 in the pulling-out direction causes the small-diameter cylindrical portion 50, the pin 60, and the large-diameter portion of the sleeve 48 to rotate. It is transmitted to the shaft 100 via 56, and the shaft 100 rotates in the pull-out direction. Due to the rotation of the shaft 100 in the pull-out direction, the above-described spiral spring is wound and tightened, and the urging force increases, thereby urging the spool 20 via the shaft 100 in the winding direction.
[0061]
As described above, in the above-mentioned mounted state, the urging force of the spiral spring acts to wind the webbing belt 28 around the spool 20, so that the webbing belt 28 basically fits the occupant's body with this urging force. The webbing belt 28 restrains and holds the occupant's body with a force corresponding to the urging force at this time.
[0062]
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 28 in the drawn state against the urging force of the spiral spring is released. Therefore, the spiral spring rotates the spool 20 in the winding direction by the urging force.
[0063]
The webbing belt 28 pulled out by the rotation of the spool 20 in the winding direction is wound in a layer around the outer periphery of the spool 20, and the webbing belt 28 is stored.
[0064]
In the present webbing take-up device 10, when the vehicle suddenly decelerates, the gas generator constituting the pretensioner mechanism 78 operates, and the ignition device instantaneously burns the gas generating agent in the gas generating unit, and instantaneously discharges a large amount of gas. Generate gas. In this way, the newly generated gas is rapidly supplied to the bottom of the cylinder 86, whereby the internal pressure at the bottom of the cylinder 86 sharply increases.
[0065]
Further, as the internal pressure on the bottom side of the cylinder 86 rises, the piston 88 rises, and the rack bar 82 integrated with the piston 88 slides upward. The rack bar 82 rises and meshes with the pinion 80 to rotate the pinion 80 in the winding direction. When the pinion 80 rotates in the winding direction, the clutch frame 68 integrated with the pinion 80 rotates in the winding direction.
[0066]
When the clutch frame 68 rotates in the winding direction from the state shown in FIG. 4, the clutch wall 72 directly or indirectly engages with the clutch roller 74 via the holding piece 76, and presses the clutch roller 74 in the winding direction. I do. The holding piece 76 on which the pressing force acts directly or indirectly breaks at the base end side, whereby the clutch roller 74 receiving the pressing force from the clutch wall 72 is guided by the clutch wall 72, and It is displaced inward in the radial direction at 68 and finally presses against the outer periphery of the large diameter portion 56 as shown in FIG.
[0067]
When the clutch roller 74 is pressed against the outer peripheral portion of the large diameter portion 56, the rotation of the clutch frame 68 in the winding direction is transmitted to the large diameter portion 56, and the large diameter portion 56 is rotated in the winding direction. The rotation of the large-diameter portion 56 in the winding direction is transmitted to the spool 20 via the pin 60 and the small-diameter cylindrical portion 50, so that when the spool 20 is rotated in the winding direction, the webbing belt 28 is attached to the spool 20. Is wound up.
[0068]
As described above, the webbing belt 28 is wound around the spool 20, so that the restraining force of the webbing belt 28 is increased, and the body of the occupant who is about to move toward the front side of the vehicle due to the inertia in the vehicle sudden deceleration state is moved. Is securely held.
[0069]
Next, after the pretensioner mechanism 78 is operated as described above, when the occupant attempts to move substantially to the front side of the vehicle due to the inertia in the vehicle sudden deceleration state, the webbing belt 28 is pulled. In this manner, when the webbing belt 28 is pulled, a rotational force is applied to the spool 20 in the pull-out direction.
[0070]
Here, when the pretensioner mechanism 78 has already been operated, the large diameter portion 56 and the clutch wall 72 (that is, the clutch frame 68) are mechanically connected via the clutch roller 74 as described above. Therefore, the rotational force applied to the spool 20 is transmitted to the pinion 80 via the small-diameter cylindrical portion 50, the pin 60, the large-diameter portion 56, the clutch roller 74, and the clutch frame 68, and rotates the pinion 80 in the pull-out direction. When the pinion 80 rotates in the pulling-out direction, the rack bar 82 already engaged with the pinion 80 is forcibly slid downward, and accordingly, the piston 88 is lowered toward the bottom of the cylinder 86.
[0071]
When the piston 88 is lowered, the inner peripheral portion of the tapered portion 94 presses the tapered portion 98 of the stopper ring 96 downward. Therefore, although the stopper ring 96 descends, the pressing force from the tapered portion 94 received by the tapered portion 98 also acts radially outward of the stopper ring 96. For this reason, the diameter of the stopper ring 96 is increased, and the outer peripheral portion is pressed against the inner peripheral portion of the cylinder 86.
[0072]
At this time, the frictional force generated between the inner peripheral portion of the cylinder 86 and the outer peripheral portion of the stopper ring 96 acts to prevent the lowering of the stopper ring 96, so that the lowering of the piston 88 via the stopper ring 96. It is regulated by the frictional force generated between the inner peripheral portion of the cylinder 86 and the outer peripheral portion of the stopper ring 96.
[0073]
In this way, when the rotation of the pinion 80 in the pulling-out direction is restricted by restricting the downward movement of the piston 88, the rotation of the large-diameter portion 56 in the pulling-out direction is indirectly restricted. Accordingly, relative rotation occurs between the large-diameter portion 56 and the small-diameter cylindrical portion 50, and when the rotational force applied to the small-diameter cylindrical portion 50 in the pull-out direction exceeds the mechanical strength of the pin 60, the pin 60 The mechanical connection between the large-diameter portion 56 and the small-diameter cylindrical portion 50 around the axis is released by shearing.
[0074]
As a result, when the spool 20 rapidly rotates in the pull-out direction, relative rotation occurs between the lock base 32 connected to one axial end of the torsion shaft 44 and the ratchet gear of the lock mechanism, and the lock plate 40 is forcibly moved. Is moved closer to the ratchet teeth 46 and meshed with the ratchet teeth 46. Thus, when the rotation of the lock base 32 is restricted, the torsion shaft 44 is twisted between one end and the other end in the axial direction, and the torsion shaft 44 is deformed. Due to the torsional deformation of the torsion shaft 44, the restraining force of the webbing belt 28 for restraining the occupant's body is prevented from becoming more than a certain value.
[0075]
Here, in the webbing take-up device 10, as described above, the pin 60 is restricted by lowering the piston 88 to cause relative rotation between the large-diameter portion 56 and the small-diameter cylindrical portion 50 of the sleeve 48 so that the pin 60 is moved. The mechanical connection between the large-diameter portion 56 and the small-diameter cylindrical portion 50 is released by breaking. Therefore, when the torsion shaft 44 is twisted, it is not affected by the internal pressure of the cylinder 86. Therefore, in the webbing take-up device 10, the mechanical strength of the torsion shaft 44 can be easily set without considering the internal pressure of the cylinder 86.
[0076]
Further, in the webbing take-up device 10, since the lowering of the piston 88 is restricted by the stopper ring 96 as described above, the rotation of the large-diameter portion 56 in the pulling-out direction does not occur even if the torsion shaft 44 rotates in the pulling-out direction. Regulated indirectly. Therefore, relative rotation can be quickly generated between the large-diameter portion 56 and the small-diameter cylindrical portion 50.
[0077]
Thus, the mechanical connection between the large-diameter portion 56 and the small-diameter cylindrical portion 50, that is, the mechanical connection between the torsion shaft 44 and the pretensioner mechanism 78 can be eliminated by shearing the pin 60 at an early stage. Energy can be generated at an early stage due to the torsion.
[0078]
<Configuration of Second Embodiment>
Next, other embodiments of the present invention will be described.
[0079]
In describing each of the following embodiments, the same parts as those in the embodiment described above including the first embodiment are basically the same as those in the embodiment described above. The reference numerals are given and the description is omitted.
[0080]
FIG. 6 is an exploded perspective view showing a configuration of a pretensioner lock unit of a webbing take-up device according to a second embodiment of the present invention.
[0081]
As shown in this figure, the pretensioner locking means in the present embodiment includes a clutch frame 122. The clutch frame 122 has basically the same configuration as the clutch frame 68, but differs from the clutch frame 68 in that a clutch plate 124 constituting a pretensioner locking means extends from the bottom side. The clutch plate 124 is conceptually divided approximately every 120 degrees around the axis of the clutch frame 68. In the range of approximately 120 degrees, the outer diameter gradually increases in the winding direction around the axis of the clutch frame 68 in the winding direction.
[0082]
A cylindrical body 126 is disposed outside the clutch plate 124 in the radial direction of rotation. The cylindrical body 126 is formed in a shallow bottomed cylindrical shape that opens toward the leg plate 18 side, and its inner diameter is larger than the maximum outer diameter of the clutch plate 124 and includes the clutch plate 124. The clutch frame 68 is fixed to the leg plate 18 coaxially with the spool 20 while being housed inside.
[0083]
Further, three shafts 128 are formed coaxially with the cylinder 126 at the inner bottom of the cylinder 126. These three shafts 128 are formed so as to correspond to the portions of the clutch plate 124 where the three outer diameters are minimum.
[0084]
A clutch roller 130 is supported on these shafts 128.
The outer diameter of these clutch rollers 130 is slightly smaller than the gap between the outer peripheral portion of the clutch plate 124 and the inner peripheral portion of the cylinder 126 at a position where the outer diameter of the clutch plate 124 is minimized. It is sufficiently larger than the gap between the outer peripheral portion of the clutch plate 124 and the inner peripheral portion of the cylinder 126 at the position where the outer diameter of the plate 124 is maximized.
[0085]
Further, a circular hole 64 is formed coaxially at the bottom of the cylindrical body 126, and the pinion 80 penetrates the circular hole 64 and protrudes outside the cylindrical body 126.
[0086]
<Operation and Effect of Second Embodiment>
That is, in the present embodiment, when the pretensioner mechanism 78 operates and the pinion 80 rotates in the winding direction in the same manner as in the first embodiment, the clutch plate 68 and the clutch plate 68 move from the state shown in FIG. 124 rotates, and the clutch plate 124 presses the clutch roller 130 in the winding direction. This pressing force acts indirectly on the shaft 128 and breaks the proximal end of the shaft 128 as shown in FIG.
As a result, the displacement of the clutch roller 130 by the shaft 128 is released, and the clutch roller 74 is moved by the pressing force from the clutch plate 124.
[0087]
Next, in a state where the large diameter portion 56 and the clutch wall 72 (that is, the clutch frame 68) are mechanically connected, the rotational force in the pulling-out direction due to the pulling force of the occupant's body to pull the webbing belt 28. Is transmitted to the clutch frame 68 via the spool 20 and the sleeve 48, and when the clutch frame 68 rotates in the pull-out direction, the clutch plate 124 rotates in the pull-out direction. However, in this state, the clutch roller 130 does not receive the pressing force in the winding direction from the clutch plate 124 which has been applied so far, so that the clutch roller 130 will stay in place, whereby the clutch plate 130 A relative rotation occurs between 124 and clutch roller 130.
[0088]
When the clutch plate 124 rotates relative to the clutch roller 130 in the pulling-out direction, the position of each clutch roller 130 becomes smaller between the outer peripheral portion of the clutch plate 124 and the inner peripheral portion of the cylindrical body 126, and as shown in FIG. As a result, the clutch roller 130 finally comes into pressure contact with both the outer peripheral portion of the clutch plate 124 and the inner peripheral portion of the cylindrical body 126 as if biting. Thus, the clutch plate 124 and the cylinder 126 are mechanically connected. Here, as described above, since the cylinder 126 is fixed to the leg plate 18, it does not rotate. Therefore, the rotation of the clutch plate 124 in the pull-out direction is restricted, and accordingly, the rotation of the large-diameter portion 56 in the pull-out direction is restricted as in the first embodiment.
[0089]
As described above, in this embodiment, the configuration of the pretensioner locking means is different from that of the first embodiment, but as described above, the occupant's body is When trying to pull out 28, the rotation of large diameter portion 56 can be restricted, so that the same operation as in the first embodiment can be achieved, and the same effect can be obtained.
[0090]
Further, in the present embodiment, the clutch plate 130 and the cylinder 126 are mechanically pressed against both the outer periphery of the clutch plate 124 and the inner periphery of the cylinder 126 as if the clutch roller 130 is engaged. It is a structure that restricts the rotation of the clutch plate 124 in the pull-out direction, and thus the rotation of the large-diameter portion 56 in the pull-out direction. For this reason, even if the torsion shaft 44 rotates in the pull-out direction, the rotation of the large-diameter portion 56 in the pull-out direction is indirectly restricted. Therefore, relative rotation can be quickly generated between the large-diameter portion 56 and the small-diameter cylindrical portion 50.
[0091]
Thus, the mechanical connection between the large-diameter portion 56 and the small-diameter cylindrical portion 50, that is, the mechanical connection between the torsion shaft 44 and the pretensioner mechanism 78 can be eliminated by shearing the pin 60 at an early stage. Energy can be generated at an early stage due to the torsion.
[0092]
<Third embodiment>
Next, a third embodiment of the present invention will be described.
[0093]
FIG. 10 is a side view showing the configuration of the pretensioner locking means of the webbing take-up device according to the present embodiment. As shown in this figure, in the present embodiment, the clutch plate 124 constituting the pretensioner locking means is not formed at the bottom of the clutch frame 68, and a ratchet plate 142 is formed instead.
[0094]
Further, a pawl 144 constituting a pretensioner locking means is pivotally supported on the shaft 128 instead of the clutch roller 130. The pawl 144 is urged by a torsion coil spring (not shown) in a direction in which its tip approaches the outer peripheral portion of the ratchet plate 142. Therefore, basically, each pawl 144 has its tip engaged with the ratchet teeth on the outer peripheral portion of the ratchet plate 142. Therefore, the pinion 80 integrated with the ratchet plate 142 can rotate in the winding direction but cannot rotate in the pull-out direction.
[0095]
That is, in the present embodiment, even if the clutch frame 68 tries to rotate in the pull-out direction after the operation of the pretensioner mechanism 78 is completed, the rotation of the ratchet plate 142 in the pull-out direction is regulated by the pawl 144, so the pull-out direction The clutch frame 68 cannot rotate. As described above, in the present embodiment, the rotation of the clutch frame 68 in the pulling-out direction can be restricted in the same manner as in the second embodiment, so that the same operation as in the second embodiment can be achieved, and the same effect can be obtained. Can be obtained.
[0096]
<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described.
[0097]
FIG. 11 is an exploded perspective view showing a configuration of a sleeve 152 as a connecting means of the webbing take-up device according to the present embodiment. As shown in this figure, the sleeve 152 in the present embodiment has the large diameter portion 56 and the small diameter cylindrical portion 50 coaxially and integrally connected, and the shaft 100 is separate from the sleeve 152. It is configured.
[0098]
In the present embodiment, the large-diameter portion 56 is formed with a bottomed circular hole 154 opened at the end opposite to the small-diameter cylindrical portion 50 coaxially with the large-diameter portion 56. . In the large diameter portion 56, a pair of key grooves 156 opened at the inner peripheral portion of the circular hole 154 and the end opposite to the small diameter cylindrical portion 50 are formed so as to face each other via the circular hole 154. I have.
[0099]
On the other hand, a fitting portion 158 is coaxially formed integrally with the shaft 100 at the base end of the shaft 100. The fitting part 158 includes a disk part 160. The outer diameter of the disk portion 160 is slightly smaller than the inner diameter of the circular hole 154, and the disk portion 160 can be fitted into the circular hole 154.
[0100]
A pair of fitting pieces 162 are formed on the outer peripheral portion of the disk portion 160 so as to face each other with the disk portion 160 interposed therebetween. The fitting piece 162 can be fitted into the key groove 156. Basically, when the fitting piece 162 is fitted into the key groove 156, the rotation of the sleeve 152 is transmitted to the shaft 100, and the fitting piece 162 is integrally formed with the sleeve 152. The configuration is such that the shaft 100 rotates.
[0101]
That is, in the present embodiment, basically, the shaft 100 and the sleeve 152 rotate integrally, but when a rotational force is applied to the sleeve 152 in a state where the lowering of the piston 88 and the rotation of the pinion 80 are restricted. Then, the fitting piece 162 is sheared by the key groove 156 and detaches from the disk portion 160. This allows the sleeve 152 to rotate relative to the shaft 100.
[0102]
As described above, in the present embodiment, when the torsion shaft 44 is twisted by the sleeve 152 being rotatable relative to the shaft 100, the sleeve 152 is not affected by the internal pressure of the cylinder 86. Therefore, also in the present embodiment, the mechanical strength of the torsion shaft 44 can be easily set without considering the internal pressure of the cylinder 86.
[0103]
<Fifth embodiment>
Next, a fifth embodiment of the present invention will be described.
[0104]
FIG. 12 is an exploded perspective view showing a configuration of a pinion 80 as a connecting means of the webbing take-up device according to the present embodiment. As shown in this figure, the connecting means in the present embodiment includes a clutch frame 172. The clutch frame 172 is basically the same as the clutch frame 68 in the first embodiment, but is configured separately from the pinion 80.
[0105]
A circular hole 174 is formed in the bottom of the clutch frame 172 coaxially with the bottom of the clutch frame 172. Further, a pair of fitting pieces 176 are formed to protrude radially inward of the circular hole 174 from the inner peripheral portion of the circular hole 174 so as to face each other via the center of the circular hole 174.
[0106]
On the other hand, the disc portion 178 is formed coaxially and integrally with the pinion 80 on the pinion 80 formed separately from the clutch frame 172. The outer diameter of the disk 178 is slightly smaller than the inner diameter of the hole 174 so that the disk 178 can be fitted into the hole 174.
[0107]
Further, on the outer peripheral portion of the disk portion 178, an end face of the disk portion 178 on the opposite side to the pinion 80 and a key groove 180 opened at the outer peripheral portion of the disk portion 178 are provided via the center of the disk portion 178. They are formed so as to face each other. The fitting piece 176 can be fitted in the key groove 180. Basically, when the fitting piece 176 is fitted in the key groove 180, the rotation of the pinion 80 is transmitted to the clutch frame 172 and integrated with the pinion 80. And the clutch frame 172 rotates.
[0108]
That is, in the present embodiment, basically, the clutch frame 172 and the pinion 80 rotate integrally, but a rotational force is applied to the clutch frame 172 in a state where the lowering of the piston 88 and the rotation of the pinion 80 are restricted. Then, the fitting piece 176 is sheared by the key groove 180 and detaches from the inner peripheral portion of the circular hole 174. Thus, the clutch frame 172 can rotate relative to the pinion 80.
[0109]
As described above, in the present embodiment, when the torsion shaft 44 is twisted by the pinion 80 being relatively rotatable with respect to the clutch frame 172, the pinion 80 is not affected by the internal pressure of the cylinder 86. Therefore, also in the present embodiment, the mechanical strength of the torsion shaft 44 can be easily set without considering the internal pressure of the cylinder 86.
[0110]
【The invention's effect】
As described above, in the webbing take-up device according to the present invention, the mechanical strength of the torsion shaft can be easily set without considering the internal pressure of the cylinder constituting the pretensioner mechanism. In addition, immediately after the rotation of the torsion shaft in the pull-out direction is started, the mechanical connection between the rotating body and the torsion shaft can be quickly released (eliminated), and energy absorption by the torsion shaft can be started at an early stage.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a configuration of a webbing take-up device according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a clutch.
FIG. 3 is a perspective view showing a configuration of a stopper ring as a pretensioner locking means.
FIG. 4 is a side sectional view showing a state before the clutch is operated.
FIG. 5 is a side sectional view showing a state after the operation of the clutch.
FIG. 6 is an exploded perspective view showing a configuration of a pretensioner locking means of a webbing take-up device according to a second embodiment of the present invention.
FIG. 7 is a side sectional view showing a state before the pretensioner locking means is operated.
FIG. 8 is a side sectional view corresponding to FIG. 7 and showing a shaft detached state.
FIG. 9 is a side sectional view showing a state after the operation of the pretensioner locking means.
FIG. 10 is a side sectional view showing a configuration of a pretensioner locking means of a webbing take-up device according to a third embodiment of the present invention.
FIG. 11 is an exploded perspective view showing a configuration of a connecting means of a webbing take-up device according to a fourth embodiment of the present invention.
FIG. 12 is an exploded perspective view showing a configuration of a connecting means of a webbing take-up device according to a fifth embodiment of the present invention.
[Explanation of symbols]
10 Webbing take-up device 20 Spool 28 Webbing belt 38 Lock mechanism (shaft locking means)
44 torsion shaft 48 sleeve (connection means)
78 Pretensioner mechanism 80 Pinion (rotating body)
82 rack bar (slide member)
86 cylinder 88 piston 96 stopper ring (pretensioner lock means)
122 Clutch frame (pretensioner locking means)
124 clutch plate (pretensioner lock means)
126 cylinder (pretensioner lock means)
130 Clutch roller (pretensioner locking means)
142 ratchet plate (pretensioner lock means)
144 Paul (Pre-tensioner lock means)
152 sleeve (connection means)
172 Clutch frame (connection means)

Claims (1)

The long belt-shaped webbing belt has a substantially cylindrical spool whose longitudinal end is locked to an outer peripheral portion, and the spool is rotated in one winding direction around its axis, whereby the outer periphery of the spool is rotated. The webbing belt is wound up from its base end side, and the webbing belt is pulled out by pulling the webbing belt toward the tip end side so as to rotate the spool in a pulling-out direction opposite to the winding direction and pull out the webbing belt. Taking device,
A torsion shaft that is provided substantially coaxially with the spool inside the spool and has one axial end integrally connected to the spool;
Shaft locking means for locking the other axial end of the torsion shaft in a vehicle sudden deceleration state,
A rotating body provided with a cylinder containing a piston that slides with a change in internal pressure in a state of rapid deceleration of the vehicle, wherein the piston that slides by increasing the internal pressure of the cylinder is provided at one axial end of the torsion shaft; A pre-tensioner mechanism for rotating in the winding direction,
The rotating body is connected to one axial end of the torsion shaft, and the rotation of the rotating body is transmitted to the torsion shaft to rotate the torsion shaft in the winding direction, and the relative rotation of the torsion shaft with respect to the rotating body. Connection means for deforming or breaking to release the connection,
A pretensioner that locks the pretensioner mechanism by restricting the rotation of the rotating body in the pulling-out direction or the sliding of the piston in a direction opposite to the sliding direction when the internal pressure is increased after completion of the rising of the piston. A webbing take-up device comprising: a lock unit.

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