JPH11227561A - Seat belt retractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further simplify a construction and reduce a size so as to reduce a manufacturing cost by installing a holding force limiting mechanism for limiting a webbing holding force of a clamp mechanism in the clamp mechanism so that a load acting on a webbing is not increased to more than a specified value so as to absorb an energy efficiently and securely. SOLUTION: In an emergency of a vehicle, first the intermediate part of a webbing is clamped by a clamp mechanism 8. When a load more than a first specified value acts on the webbing, the webbing is allowed to be pulled out so that an energy is absorbed through a friction. When a load more than a second specified value larger than the first specified value acts on the webbing, a deformed member 6 is held pressingly by the webbing and the shell part of a winding drum 5 in parallel with the energy absorption by the clamp mechanism 8 so as to deform the drum in radially contracting direction for energy absorption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt retractor, and in particular, in a vehicle emergency, first clamps a webbing by a clamp mechanism to absorb energy through its sliding friction, and then further parallels the energy absorption by the clamp mechanism. The present invention relates to a seat belt retractor in which energy is absorbed by an energy absorbing mechanism.

[0002]

2. Description of the Related Art Conventionally, in a seat belt retractor mounted on an automobile, a webbing drawn from a winding drum is set on a waist, a chest, etc. of an occupant sitting on a seat. In the event of a vehicle emergency due to a collision or the like, the take-up drum is locked non-rotatably by the emergency lock mechanism, preventing the webbing from being pulled out from the take-up drum, and the webbing does not cause the occupant to collide with the steering wheel, the front window, etc. To be restrained.

However, in the event of a vehicle emergency, if the deceleration of the vehicle is very large and the inertial force acting on the occupant becomes very large, the load received by the occupant from the webbing becomes very large, which is not desirable. Therefore, in recent seat belt retractors, when the rotation of the winding drum is almost locked by the emergency lock mechanism and the load acting on the webbing increases, the webbing is gradually pulled out while absorbing energy, and the load acting on the occupant is reduced. Many are designed to ease.

For example, in a seat belt retractor disclosed in Japanese Patent Application Laid-Open No. 7-285416, in addition to an emergency lock mechanism, a plate member fixedly provided near a webbing passage in a housing accommodating a winding drum, A clamp member that clamps the webbing in cooperation with the plate member.In the beginning, the clamp member is guided in the direction to approach and separate from the plate member, and when the webbing is clamped, the clamp member is prevented from moving in the webbing pull-out direction. And a deformable member provided on the outer peripheral side of the body of the winding drum.

In a vehicle emergency, the rotation of the winding drum is locked by the emergency lock mechanism, and the webbing is clamped by the clamp member and the plate member in a state where a plurality of projections formed on the clamp member are cut into the webbing. Is done. Thereafter, when the load acting on the webbing increases, first, the clamp member moves integrally with the webbing in the webbing withdrawing direction to plastically deform the guide member, thereby absorbing energy.

When the clamp member moves a predetermined distance in the webbing pull-out direction, the clamp member comes into contact with the restricting portion at the distal end portion of the guide member to restrict the movement thereof. The projection is broken or deformed, and the webbing is released from the clamp. Subsequently, the webbing is tightened in the winding drum and the webbing is pulled out, and then the deformation member is sandwiched between the webbing and the body of the winding drum. It is pressurized and plastically deforms in the diameter reducing direction to perform energy absorption.

As described above, in this type of seat belt retractor in which energy is absorbed in two stages while feeding webbing, the amount of energy absorption is large.
It is excellent in that energy can be absorbed without applying a large load to the occupant in the event of a vehicle emergency, particularly when the deceleration of the vehicle becomes extremely large.

[0008]

However, in the seat belt retractor disclosed in Japanese Patent Application Laid-Open No. 7-285416, after the clamp member is moved in the webbing withdrawing direction to deform the guide member and perform energy absorption,
After the webbing is released from the clamp due to the breakage or deformation of the projection of the clamp member, the deformable member provided on the outer peripheral side of the winding drum is further deformed, so that two deformable members are required.

Further, in this seat belt retractor,
The structure is complicated and the manufacturing cost is reduced due to the need to provide a guide member that plastically deforms due to the movement of the clamp member in the webbing withdrawal direction, and the need to form multiple protrusions on the clamp member to release the clamp. There is a problem that it becomes expensive, and a moving space for moving the clamp member in the webbing withdrawing direction must be provided, so that there is a problem that the seat belt retractor becomes large.

An object of the present invention is to efficiently and reliably absorb energy in a seat belt retractor.
Further, the structure can be simplified and downsized to reduce the manufacturing cost.

[0011]

According to a first aspect of the present invention, there is provided a seat belt retractor which clamps an intermediate portion of a webbing in a vehicle emergency and adds frictional resistance to the webbing while allowing the webbing to be pulled out to absorb energy. And a clamping force limiting mechanism for limiting the webbing clamping force of the clamp mechanism so that the load acting on the webbing does not increase beyond a predetermined value.

In the event of a vehicle emergency, the clamping mechanism can clamp the middle of the webbing and add frictional resistance to the webbing while allowing the webbing to be pulled out to absorb energy. At this time, the clamping force limiting mechanism is used. Since the webbing holding force of the clamp mechanism is limited so that the load acting on the webbing does not increase beyond a predetermined value, energy absorption can be efficiently and reliably performed without applying a large load to the occupant. In the case where the rotation of the winding drum for winding the webbing is locked in the event of a vehicle emergency, energy can be absorbed also by tightening the webbing on the winding drum.

According to a second aspect of the present invention, there is provided a seat belt retractor for clamping a webbing in the middle of an emergency in a vehicle emergency and adding frictional resistance to the webbing while allowing the webbing to be pulled out to absorb energy, and a clamp mechanism comprising the clamp mechanism. An energy absorbing mechanism that starts operation later than the start of energy absorption and performs energy absorption in parallel with energy absorption by the clamp mechanism.

In the event of a vehicle emergency, energy is absorbed by clamping the webbing in the middle of the webbing and adding frictional resistance to the webbing while allowing the webbing to be pulled out, and then the energy absorbing mechanism absorbs energy by the clamp mechanism. The operation starts later than the start, and the energy absorption mechanism can perform energy absorption in parallel with energy absorption by the clamp mechanism. Therefore, there is no possibility that the load acting on the webbing is reduced at all, and the energy can be absorbed very efficiently and reliably.

According to a third aspect of the present invention, there is provided a seat belt retractor including a winding drum for winding the webbing, an emergency lock mechanism for locking the rotation of the winding drum in a vehicle emergency, and a webbing for the webbing in conjunction with the locking operation of the emergency locking mechanism. A clamping mechanism that clamps the middle part and allows the webbing to be withdrawn when a load equal to or more than a first predetermined value acts on the webbing and absorbs energy through friction; and a webbing wound around the winding drum. The webbing and the body of the winding drum are provided on the outer peripheral side of the body of the winding drum so that the webbing and the body of the winding drum are positioned when the load on the webbing is greater than a second predetermined value greater than the first predetermined value. And a deformable member that absorbs energy by being pressed in and deforming in the diameter reducing direction.

In the event of a vehicle emergency, first, the rotation of the winding drum is locked by the emergency lock mechanism, and the clamp mechanism is operated in conjunction with the locking operation of the emergency lock mechanism. Is pulled out, and the occupant is restrained by the webbing. Thereafter, when the load acting on the webbing rises and becomes equal to or more than the first predetermined value, the webbing is pulled out by the clamp mechanism, and energy is absorbed through friction. However, the pulling out of the webbing during this time is due to the tightening of the webbing on the winding drum.

Thereafter, the load acting on the webbing is changed to the second
When the predetermined value or more, the deformation member is pinched by the webbing and the body of the winding drum and deformed in the diameter reducing direction, energy is absorbed while the webbing is gradually fed out, and when the deformation member is completely deformed, The webbing is not extended, and the occupant is firmly restrained by the webbing.

That is, while the energy absorption is continuously performed through the friction of the webbing by the clamp mechanism, the deformation member is pressed by the webbing and the body of the winding drum and deformed in the diameter reducing direction to absorb the energy. Therefore, there is no possibility that the load acting on the webbing is reduced at all, and energy absorption is performed very efficiently and reliably.

According to a fourth aspect of the present invention, there is provided a seat belt retractor for winding up the webbing, an emergency lock mechanism for locking the rotation of the windup drum in a vehicle emergency, and a webbing for the webbing in conjunction with the locking operation of the emergency lock mechanism. A clamp mechanism that clamps the middle part and allows the webbing to be withdrawn when a load equal to or more than the first predetermined value acts on the webbing and absorbs energy through friction. A torsion bar whose rotation is restrained and whose tip rotates integrally with the winding drum. When a load greater than a second predetermined value greater than a first predetermined value acts on the webbing, the torsion bar is torsionally deformed. And a torsion bar that absorbs energy.

In a vehicle emergency, first, the base end of the torsion bar is rotationally restrained by the emergency lock mechanism, the rotation of the winding drum is locked through the torsion bar, and the clamp is interlocked with the locking operation of the emergency lock mechanism. When the mechanism is activated and the middle part of the webbing is clamped, the webbing is prevented from being pulled out, and the occupant is restrained by the webbing. Thereafter, when the load acting on the webbing rises and becomes equal to or more than the first predetermined value, the webbing is pulled out by the clamp mechanism, and energy is absorbed through friction. However, the pulling out of the webbing during this time is due to the tightening of the webbing on the winding drum.

Thereafter, the load acting on the webbing is changed to the second
When the value exceeds a predetermined value, the torsion bar is torsionally deformed, and the rotating drum rotates together with the tip of the torsion bar, and energy is absorbed while the webbing is gradually pulled out. In addition, when the amount of torsional deformation of the torsion bar becomes a predetermined value, by configuring so that the rotation of the tip of the torsion bar is also locked, when the amount of torsional deformation of the torsion bar becomes a predetermined value, The rotation of the winding drum is restricted, the webbing is not fed out, and the occupant is strongly restrained by the webbing.

In other words, the energy can be absorbed by torsionally deforming the torsion bar while continuously absorbing the energy through the friction of the webbing by the clamp mechanism. There is no danger of the applied load being reduced at all, and the energy absorption is performed very efficiently and reliably.

According to a fifth aspect of the present invention, there is provided the seat belt retractor according to the third or fourth aspect of the present invention, wherein the clamp mechanism is configured such that the load acting on the webbing by the clamp mechanism is the first.
It is characterized by having a pinching force limiting mechanism for limiting the webbing pinching force so as not to exceed a predetermined value. Therefore, when a load equal to or more than the first predetermined value is applied to the webbing, the webbing can be reliably pulled out by the clamp mechanism and energy can be absorbed through friction. The first predetermined value can be set to a desired value by adjusting the webbing clamping force by the clamping force limiting mechanism. Other effects are the same as those of the third or fourth aspect.

According to a sixth aspect of the present invention, in the seat belt retractor according to any one of the first to fifth aspects, the clamp mechanism has a pair of clamp members opposed to each other across the webbing. A pair of holding portions are provided at least at both end portions in the webbing passing direction among the opposing surfaces, and a non-holding portion is provided between the holding portions. Therefore, a clamping force can be uniformly applied to the webbing from the entire holding portion, and the performance of the clamping mechanism can be improved. Therefore, it is easy to set the predetermined value. Other claims 1
The same operation as that of any one of the fifth aspect is obtained.

According to a seventh aspect of the present invention, in the invention of the sixth aspect, each of the holding portions is formed in one of the clamp members, and is formed in a concave portion having a narrow width in the webbing passing direction and the other of the clamp members. And a convex portion engaging with the concave portion. In each holding portion, the webbing is clamped by the engagement between the concave portion and the convex portion, so that the webbing can be securely held and the performance of the clamp mechanism can be further improved. Other operations are the same as those of the sixth aspect.

According to an eighth aspect of the present invention, in the seat belt retractor according to the first or second aspect, an emergency lock mechanism for locking the rotation of the winding drum in a vehicle emergency, and a webbing wound on the winding drum in a vehicle emergency. And a feed permitting means for permitting the feed.

In the event of a vehicle emergency, the rotation of the winding drum is locked by the emergency lock mechanism. However, the webbing wound around the drum is allowed to be fed by the feeding allowance means. Energy can be reliably absorbed. Other operations are the same as those of the first or second aspect.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. However, the front, rear, left and right in FIG.

As shown in FIGS. 1 to 3, the seat belt retractor 1 includes a metal housing 2 fixed to a vehicle body, a winding shaft 3 rotatably supported by the housing 2, and a winding shaft 3. A rotation urging mechanism (not shown) for rotationally urging in the winding direction, an emergency lock mechanism 4 for locking the rotation of the winding shaft 3 in the event of a vehicle emergency such as a vehicle collision, etc. A take-up drum 5 made of synthetic resin for taking up the webbing W to be fitted therein, and body portions 51 and 6 of the take-up drum 5
1, a deformable member 6 made of synthetic resin provided on the outer peripheral side, a notifying member 7 provided on the winding drum 5 side for notifying that the deformable member 6 is deformed (see FIG. 5), and a locking operation of the emergency lock mechanism 4 And a clamp mechanism 8 for clamping a middle portion of the webbing W extending from the winding drum 5 in conjunction with the above.

As shown in FIG. 1, the housing 2 comprises a left side wall 10, a right side wall 11, a rear upper wall portion 12 connecting the left side wall 10 and the rear upper portion of the right side wall 11, a left side wall 10 and a right side wall. 1
The rear lower wall portion 13 that connects the rear lower portion 1 is integrally formed, and the rear upper wall portion 12 and the rear lower wall portion 13 are fixed to the vehicle body with bolts or the like. The front ends of the left side wall 10 and the right side wall 11 are connected and reinforced by a bar member 14 oriented in the left-right direction.

On the left side wall 10 and the right side wall 11, circular openings 15, 16 having a smaller diameter than the winding drum 5 are formed concentrically, and pivot holes 17, 18 are formed concentrically above them. . A curved shaft insertion hole 19 is formed in the right side wall 11 at the rear lower side of the pivot hole 18, and the emergency lock mechanism 4
The pawl 35 and the holder 42 are mounted. A rectangular opening 2a is formed between the rear upper wall portion 12 and the rear lower wall portion 13. Although not shown, the webbing W
Is wound up, the rear end portion of the webbing W, whose diameter increases, reaches the inside of the opening 2a so that it does not interfere with the housing 2.

As shown in FIG. 3, the winding shaft 3 is formed so as to be able to be inserted into insertion holes 53 and 63 (see FIGS. 4 and 5) having a substantially rectangular cross section of the winding drum 5, and an emergency The ratchet wheel 30 of the lock mechanism 4 is integrally formed, and the connecting shaft 21 is integrally formed at the right end thereof. Winding shaft 3
A webbing insertion hole 20 is formed in the webbing W. The base end portion of the webbing W is inserted into the webbing insertion hole 20, and the locked member fitted inside the loop portion of the base end of the webbing W is inserted into the webbing insertion hole 20. Cannot be inserted through the shaft 3 and is locked and fixed to the winding shaft 3. A pair of engagement grooves 22 is formed at the tip of the winding shaft 3.

The emergency lock mechanism 4 will be described.
As shown in FIGS. 1 to 3, the emergency lock mechanism 4 locks the rotation of the winding drum 5 via the winding shaft 3 in the event of a vehicle emergency, and prevents the webbing W from being pulled out due to the rotation of the winding drum 5. A ratchet wheel 30 integrally formed with the winding shaft 3, a first lock mechanism for locking the rotation of the ratchet wheel 30 in response to sudden withdrawal of the webbing W, and a ratchet in response to rapid deceleration of the vehicle. A second lock mechanism for locking the rotation of the wheel 30 is provided.
The emergency lock mechanism 4 is covered by a cover member 4a fixed to the right side wall 11 of the housing 2.

The first lock mechanism includes a pawl 35 pivotally supported by a shaft 36 fixed to the right side wall 11 of the housing 2 and capable of engaging with the ratchet gear 30a, and a connecting shaft of the winding shaft 3. The pawl 35 is pivotally supported by the ratchet gear 3
Guide portion 3 for guiding in the engagement / disengagement direction with respect to 0a
7a, a lock arm base 45 connected to the connecting shaft 21 and housed in the cylindrical portion 37b of the clutch member 37, and a lock arm base 45.
A projection 38a is formed so as to be swingable and engages with the internal teeth 37c formed inside the cylindrical portion 37b of the clutch member 37, and is normally attached to the direction in which the projection 38a does not engage with the internal teeth 37c. The urged lock arm 38 and the connecting shaft 2
The lock gear 40 is constituted by a rocking gear 40 pivotally supported by 1 and stopped by a rivet 41, a lock arm guide (not shown) which abuts on the lock arm 38 and is frictionally coupled to the locking gear 40.

In the normal state, the pawl 35 is rotationally urged by the torsion spring 39 to a disengaged position where the pawl 35 is not engaged with the ratchet gear 30a, and when the webbing W is suddenly pulled out and the connecting shaft 21 rotates. The rotation of the locking gear 40 is delayed with respect to the lock arm base 45, and the rotation of the lock arm guide is also delayed. As a result, the lock arm 38 rotates against the spring force, and the projection 38a engages with the internal teeth 37c. Then, the clutch member 37 rotates, and the pawl 35 is guided by the guide portion 37a of the clutch member 37 and rotates against the urging force of the torsion spring 39 to engage with the ratchet gear 30a.
At the same time, the rotation of the winding drum 5 is locked via the winding shaft 3.

The second lock mechanism is pivotally supported by the connecting shaft 21 on the right side of the pawl 35, the clutch member 37, the lock arm base 45, the lock arm 38, and the lock arm 38, which are common to the first lock mechanism, and is disengaged by the rivets 41. The locking gear 40 stopped, the holder 42 fixed to the right side wall 10 of the housing 2, the spherical inertial mass 43 accommodated in the holder 42, and connected to the holder 42 so as to be swingable and to the locking gear 40. It has a swing lever 44 that can be engaged.

In the normal state, the locking gear 40 rotates integrally with the connecting shaft portion 21 of the winding shaft 3 via frictional force, and when the vehicle suddenly decelerates, the inertial mass 43 accommodated in the holder 42 Is moved, the swing lever 44 swings and engages with the locking gear 40, and the rotation of the locking gear 40 is locked. Then, due to the relative rotation of the lock arm 38 with respect to the lock arm guide of the locking gear 40, the projection 38a is engaged with the internal teeth 37c, and the clutch member 37 is rotated. Thus, the rotation of the winding drum 5 is locked.

The rotation urging mechanism is provided on the left side of the housing 2 and is configured to rotationally urge the winding drum 5 via the winding shaft 3; Therefore, the detailed description is omitted.

The winding drum 5, the deformation member 6, and the notification member 7 will be described. As shown in FIGS. 4 to 9, the winding drum 5 includes a winding drum left divided body 50 and a winding drum right divided body 60 that are divided about 1: 2 at an intermediate portion in the axial direction. The deformable member divided portions 70 and 75 corresponding to the deformable member 6 are integrally formed on the outer peripheral portions of the body portions 51 and 61 of the winding drum divided bodies 50 and 60, respectively. Note that the division positions of the left take-up drum 50 and the right take-up drum 60, that is, their lengths, can be changed as appropriate.

As shown in FIGS. 6 and 7, the winding drum left divided body 50 has a body 51 and a flange 52 integrally formed on the left end thereof. And openings 54 and 55 communicating from the outer peripheral side to the insertion hole 53 over the entire length of the body 50 are formed in opposition to each other. A pair of pin portions 56 and a pair of engaging portions 57 projecting rightward are formed at the right end of the body portion 51.

The body 51 has an insertion hole 5 from the outer peripheral side.
3, a pin hole 51a is formed at the end of the pin 3 so as to communicate orthogonally.
With the left portion of the winding shaft 3 inserted through the insertion hole 53, the pin-shaped stake 51b is pressed into the pin hole 51a and the engagement groove 2 of the winding shaft 3 is inserted.
2, the winding shaft 3 is prevented from being pulled out of the winding drum left divided body 50. The flange 52 has a fragile portion 58 formed by the left end of the notification member 7 when the notification member 7 extends in the axial direction. The weak portion 58 has a pair of claw portions on the left end of the notification member 7. A pair of engaging holes 59 with which 81 are engaged are formed.

On the other hand, as shown in FIGS. 8 and 9, the winding drum right split body 60 has a body 61 and a flange 62 integrally formed at the right end thereof. An insertion hole 63 through which the right part of the shaft 3 is inserted and openings 64 and 65 communicating from the outer peripheral side to the insertion hole 63 over the entire length of the body 61 are formed in opposition. A pair of protruding engagement claws 66 and a pair of pin holes 67 are formed at the left end of the body 61. The flange 62 is formed with a fragile portion 68 that can be broken by the right end of the notification member 7 when the notification member 7 extends in the axial direction.
A pair of engagement holes 69 with which the pair of claw portions 81 are engaged are formed.

A pair of pin portions 56 of the winding drum left divided body 50 are fitted with a pair of pin holes 67 of the winding drum right divided body 60.
, And a pair of engaging claws 66 of the winding drum right divided body 60 are engaged with a pair of engaging portions 57 of the winding drum left divided body 50.
, The winding drum left divided body 50 and the winding drum right divided body 60 are integrally connected, and the trunk portions 51, 61, the insertion holes 53, 63, the openings 54, 64, and the openings 55, 65 are formed. Each is connected.

As shown in FIG. 4 to FIG.
Is provided on the outer peripheral side of the body portions 51, 52 of the winding drum 5 so as to be located inside the webbing W wound on the winding drum 5, and the webbing W has a second larger value than the first predetermined value F1. When a load equal to or greater than the predetermined value F2 is applied, the webbing W is pressed between the body portions 51 and 52 of the winding drum 5 and deformed in the diameter reducing direction to absorb energy. A deformable member left division 70 and a deformable member right division 75 are integrally formed on the bodies 50 and 60, respectively. Here, the first predetermined value F1 is a load that allows the webbing W clamped by the clamp mechanism 8 described later to be pulled out through friction.

As shown in FIGS. 6 and 7, the deformable member left divided portion 70 is formed of a plurality of rectangular plate-shaped raised portions extending substantially radially outward from the outer periphery of the body portion 51 of the winding drum left divided body 50. 71a to 71i and two pairs of upright portions 71b, 71c, 71
d and 71e have partial cylindrical bridge portions 72a and 72b respectively connecting the tip portions thereof, and a housing portion for housing the left portion of the notification member 7 inside the pair of upright portions 71b and 71c and the bridge portion 72a. 73 is formed, and the weak portion 5 is
8 is located.

As shown in FIGS. 8 and 9, the deformable member right divided portion 75 is formed of a plurality of rectangular plate-shaped standing portions extending substantially radially outward from the outer peripheral portion of the body 61 of the winding drum right divided body 60. 76a to 76j and four pairs of upright portions 76b, 76c, 71
d, 71e, 76f, 76g, 76h, and 76i, each of which has a partially cylindrical bridge portion 77a to 77d for connecting the tip portion thereof, and a pair of upright portions 76b, 76c and a notification member 7 inside the bridge portion 77a. Is formed at the right end of the housing portion 78. The weak portion 68 is located at the right end of the housing portion 78.

As shown in FIGS. 6 and 8, the upright portions 71b to 71e and 71g to 71i of the deformable member left dividing portion 70 and the upright portions 76b to 76j of the deformable member right dividing portion 75 It is inclined about 10 degrees in the webbing pull-out direction indicated by the arrow with respect to the radial direction. Winding drum left split body 5
When the winding drum 0 and the winding drum right divided body 60 are integrally connected, the corresponding upright portions and bridge portions of the deformable member left divided portion 70 and the deformable member left divided portion 75 become substantially continuous.

The upright portions 71a and 71f are not inclined in the webbing pull-out direction indicated by the arrow with respect to the radial direction of the winding drum 5, but may be inclined in the same manner as the upright portions. The second predetermined value F2 can be appropriately set depending on the design of the deformable member 6.

As shown in FIGS. 5, 10, and 11, the notification member 7 is provided between the body portions 51, 61 of the winding drum 5 and the deformable member 6, and extends in the diameter reducing direction of the deformable member 6. Is deformed so as to project through the winding drum 5 and abut against the side walls 10 and 11 of the housing 2 to notify that the deformable member 6 has been deformed.

The notification member 7 comprises a bar member made of an aluminum plate. The notification member 7 has two bent extending portions 80 which are extended by deformation of the deformable member 6 in the radial direction. The winding drum 5 is accommodated in the accommodating portions 73 and 78 of the member 6 and arranged in the axial direction of the winding drum 5. The notification member 7 has substantially the same length as the body portions 51 and 61 of the winding drum 5, and a pair of claw portions 81 are formed at both left and right end portions of the notification member 7, respectively. A pair of claw portions 81 of the stored notification member 7 are engaged with a pair of engagement holes 59 and 69 in which the weak portions 58 and 68 are formed, respectively.

The clamp mechanism 8 will be described. The clamp mechanism 8 clamps an intermediate portion of the webbing W in conjunction with the locking operation of the emergency lock mechanism 4 and allows the webbing W to be pulled out when a load equal to or more than the first predetermined value F1 is applied to the webbing W and friction is applied. Is a mechanism that absorbs energy through

As shown in FIGS. 1 and 2 and FIGS. 12 to 15, the clamp mechanism 8 includes a pair of side walls 1 of the housing 2.
The arm 90 has one end pivotally supported between them, a movable clamp member 91 rotatably connected to the other end of the arm 90, and a rear upper wall 12 of the housing 2.
Base clamp member 92 which can move up and down along the front surface of
And an operating member 93 operatively connected to the emergency lock mechanism 4 and an upper end thereof rotatably connected to the other end of the arm 90, and the webbing W by clamp members 91 and 92.
Has a pinching force limiting mechanism 95 that limits the webbing pinching force so that the load acting on the webbing does not increase beyond the first predetermined value F1.

A pivot shaft 90a is inserted into one end of the arm 90, and the end of the pivot shaft 90a protrudes from the end of the arm 90, and the pivot hole 17 of the pair of side walls 10, 11 of the housing 2 is formed. , 18 are pivotally supported. Arm 90
A shaft portion 90b projecting rightward is fixed to the other end of the shaft member 90. The shaft portion 90b extends rightward through the shaft insertion hole 19 of the right side wall 11, and an upper end portion of the operating member 93 is provided at the right end portion. Is pivoted.

The base clamp member 92 is fixed to the first guide member 97, and the movable clamp member 91 moves toward and away from the base guide member 92 (in the front-rear direction). Guide is freely supported. The first guide member 97 is supported by a second guide member 98 fixed to the front surface of the rear upper wall portion 12 of the housing 2 so as to be vertically movable.

In the normal state, the operating member 93 is urged by the coil spring 94, and there is a gap between the base clamp member 92 and the movable clamp member 91. However, when the emergency lock mechanism 4 is operated in a vehicle emergency, the operating member 93 is activated. Moves upward against the urging force of the coil spring 94, and the arm 90 swings counterclockwise about the pivot shaft 90a together with the movable clamp member 91 in a right side view, so that the movable clamp member 91 and the base clamp are rotated. The webbing W is clamped by the member 92.

The holding force limiting mechanism 95 is provided with the second guide member 9.
8 has a locking portion 96 formed at the upper end portion, and locks the upper end portion of the first guide member 97 with the locking portion 96 to limit the webbing clamping force. In other words, the movable clamp member 91 moves closer to the base clamp member 92 as it moves upward before reaching the height position of the pivot 90 a of the arm 90, and the webbing clamping force increases. By locking the first guide member 97 and restricting the upward movement of the movable clamp member 91 together with the first guide member 97, the load acting on the webbing W by the clamp members 91 and 92 becomes greater than the first predetermined value F1. The webbing holding force is limited so as not to increase.

The operation of the seat belt retractor 1 will be described with reference to the load characteristics of the webbing shown in FIGS. 12 to 15 and FIG. In a normal state, the emergency lock mechanism 4 does not operate, and as shown in FIG. 12, the intermediate portion of the webbing W extending from the winding drum 5 is not clamped by the clamp mechanism 8, so that the webbing W
Can be freely drawn from

When the webbing W is set on the occupant's chest, waist, or the like, in the event of a vehicle emergency such as a vehicle collision, first,
Immediately after the rotation of the winding drum 5 is locked via the winding shaft 3 by the emergency locking mechanism 4, as shown in FIG. 13, the movable clamp member 91 and the base clamp member are together with the first guide member 97. 92 moves slightly upward, and the clamp mechanism 8 clamps the middle of the webbing W extending from the winding drum 5.

Thereafter, while increasing the webbing clamping force, the movable clamp member 91 is moved together with the first guide member 97.
1 and the base clamp member 92 move further upward, and FIG.
As shown in FIG. 4, when the upper end of the first guide member 97 is locked by the locking portion 96 of the clamping force limiting mechanism 95, and the load acting on the webbing W increases and becomes equal to or more than the first predetermined value F1,
The webbing W clamped by the clamp mechanism 8 is
The energy starts to slide out against the sandwiching frictional force acting from the clamp members 91 and 92 and the energy is absorbed.

Immediately after a vehicle emergency, since the rotation of the winding drum 5 is locked by the emergency lock mechanism 4, the webbing W is pulled out during this time because the webbing W is tightly wound on the winding drum 5. The webbing W is fed out from the webbing L1 (for example, L1 = 4 cm).
Until the tightening of the winding is substantially completed, the webbing W is allowed to be pulled out by the clamp mechanism 8, energy is absorbed through friction, and the impact acting on the occupant is reduced.

Thereafter, when the load of the webbing W increases and becomes equal to or more than the second predetermined value F2, the deformable member 6
As a result, the webbing W is pulled out and the webbing W is drawn out, energy is absorbed, and the impact acting on the occupant is reduced. Thereafter, as shown in FIG. 15, after the deformable member 6 is completely deformed in the diameter reducing direction and the webbing W is drawn out by L2 (for example, L2 = 30 cm), the webbing W is hardly drawn out, and The occupant is firmly restrained.

Here, from the state of FIG. 10, when the deformable member 6 is pinched by the webbing W and the body portions 51 and 61 of the winding drum 5 and deforms in the radially-reducing direction, the deformation causes the notifying member 7 Since the two extending portions 80 are plastically deformed and extended, and the length of the notification member 7 is increased, both ends of the notification member 7 are connected to the pair of fragile portions 58 of the winding drum 5 as shown in FIG.
68 is broken and protrudes through the flanges 52 and 62 of the winding drum 5 to strongly contact the side walls 10 and 11 of the housing 2.

When the deformable member 6 is once deformed in the diameter reducing direction,
Thereafter, both ends of the notification member 7 are connected to the side wall 1 of the housing 2.
0, 11 is maintained in a strong contact state with the notification member 7.
It becomes difficult for the winding drum 5 to rotate due to the frictional force acting between the webbing W and the side walls 10 and 11, so that the webbing W can be smoothly pulled out from the winding drum 5 and the webbing W can be smoothly wound on the winding drum 5. The deformation or deformation of the deformable member 6 can be easily and surely confirmed because the noise is generated when the take-up drum 5 rotates, or as a result, and as a result, it is easy to determine whether or not the seat belt retractor needs to be replaced. Can be determined.

According to the seat belt retractor 1,
In the event of a vehicle emergency, after the rotation of the winding drum 5 is locked by the emergency lock mechanism 4, first, a middle part of the webbing W is clamped by the clamp mechanism 8 and the webbing W
When a load equal to or more than the predetermined value F1 is applied, the webbing W is allowed to be pulled out and energy is absorbed through friction. Next, when a load equal to or more than the second predetermined value F2 is applied to the webbing W, the ebbing W And the trunks 51 and 61 of the winding drum 5
Thus, the deformation member 6 can be compressed and deformed in the diameter reducing direction to absorb energy.

That is, while the clamp mechanism 8 continuously absorbs energy through friction of the webbing W,
Since the webbing W and the body portions 51 and 61 of the take-up drum 5 squeeze the deformable member 6 to deform in the radially-reducing direction to absorb energy, the load acting on the webbing W may be reduced at all. And energy absorption can be performed very efficiently and reliably.

Further, no member for absorbing energy is required other than the deformable member 6, and the operation of the clamp mechanism 8 is simple as before, so that the structure can be simplified and downsized, and the manufacturing cost can be reduced. can do. Moreover, the clamping mechanism 8 allows the webbing W
Has a clamping force limiting mechanism 85 for restricting the webbing clamping force so that the load acting on the webbing W does not increase more than the first predetermined value F1. The mechanism 8 can reliably allow the webbing W to be pulled out and can absorb energy through friction. The pinching force limiting mechanism 85 adjusts the webbing pinching force to set the first predetermined value F1 to a desired value. It can be set to a value.

Next, a first alternative embodiment will be described.
Note that the same components as those of the above-described embodiment will be described by assigning the same reference numerals. However, the front, rear, left and right in FIG.

As shown in FIGS. 17 and 18, a seat belt retractor 1A includes a metal housing 100 fixed to a vehicle body, a winding drum 101 mounted on the housing 100 and winding a webbing W, and a winding drum 101. A spindle shaft as a torsion bar, which is disposed so as to be inserted into the
102, a rotation urging mechanism (not shown) for constantly urging the winding drum 101 in the winding direction, and a spindle shaft in the event of a vehicle emergency.
An emergency lock mechanism 4 for locking the vicinity of the right end of the web 102 in a non-rotatable manner, a clamp mechanism 8 for interlocking the webbing W extending from the winding drum 5 in conjunction with the locking operation of the emergency lock mechanism 4, and a spindle shaft in the event of a vehicle emergency. The torsional deformation of the spindle shaft 102 is allowed until the amount of torsional deformation rotation of the left end portion near the right end of the spindle 102 reaches a predetermined value, and when the amount of torsional deformation rotation reaches the predetermined value, the spindle shaft 102
102 and a winding mechanism 101 (see FIGS. 21 to 23) for fastening the take-up drum 101 so that it cannot rotate relatively.

As shown in FIG. 17, the left side wall 10 and the right side wall 11 of the housing 100 are slightly larger than the circular openings 15 and 16 of the housing 2 of the above-described embodiment, and have a smaller diameter than the winding drum 101. The circular openings 15A and 16A are formed concentrically. The other structure of the housing 100 is the same as that of the housing 2 of the above-described embodiment, and a description thereof will be omitted.

As shown in FIGS. 17 and 19 to 23, the winding drum 101 has a body 110 around which the webbing W is wound around the outer periphery, a left flange 111, and a right flange 112. An insertion hole 113 is formed in the center of the shaft so that the spindle shaft 102 is inserted in the left-right direction. A spline hole 114 is formed in the left flange 111, and an insertion hole 115 communicating with the insertion hole 113 and the spline hole 114 and having a diameter larger than the insertion hole 113 is formed in the left end portion of the winding drum 101. Have been.

The right flange-shaped portion 112 is formed wide in the right and left direction, and a spline-shaped fitting hole 116 communicating with the insertion hole 113 and having a diameter larger than that of the insertion hole 113 is formed in a central portion thereof. The ring member 130 of the fastening mechanism 103 is fitted in the hole 116 so as to be relatively non-rotatable and relatively movable left and right. The body 110 has a webbing insertion opening 117 for fitting and fixing the base end of the webbing W.

As shown in FIGS. 17 to 23, the spindle shaft 102 is torsionally deformed when a load equal to or greater than the second predetermined value F2 greater than the first predetermined value F1 is applied to the webbing W, thereby absorbing energy. A torsion bar portion 120, a knurled shaft portion 121 on the left end side of the torsion bar portion 120, and a spline shaft portion 122 on the right end side of the torsion bar portion 120,
The knurled shaft portion 121 is integrally formed with the right end side connection shaft portion 123 of the spline shaft portion 122 so as to be relatively non-rotatably engaged with the left end portion of the winding drum 101 via a cap member 125, The ratchet wheel 30A of the emergency lock mechanism 4 is connected to the spline shaft 122 so as to be non-rotatable.

The cap member 125 has a spline-shaped engaging portion 126, a cylindrical portion 127 extending rightward from the engaging portion 126, and a knurled hole portion 128 formed inside the cylindrical portion 127. The joint 126 is formed by the spline hole 114 of the winding drum 101.
The cylindrical portion 127 is inserted into the insertion hole 115, and the knurled shaft portion of the spindle shaft 102 is inserted into the knurled hole portion 128.
121 is engaged. The cap member 125 has a connecting shaft portion 129 having a square cross section and extending leftward from the engaging portion 126.
Are integrally formed, and the connecting shaft portion 129 is operatively connected to the rotation urging mechanism.

Although not shown, the spindle shaft 102
The cylindrical portion at the base end of the webbing W is externally fitted to the torsion bar portion 120, and the webbing W is
Then, it extends through the webbing insertion opening 117 of the body 110 of the winding drum 101 and is wound around the body 110.

Since the rotation urging mechanism is a well-known technique, the description thereof is omitted, and the structures and operations of the emergency lock mechanism 4 and the clamp mechanism 8 are the same as those in the above-described embodiment, and thus the description is omitted. I do. However, while the ratchet wheel 30 of the above embodiment is formed integrally with the winding shaft 3, the ratchet wheel 30A of this embodiment is separate from the spindle shaft 102. A cylindrical guide 119 of the ratchet wheel 30A is rotatably supported by being fitted in the circular opening 16A of the housing 100 via a ring-shaped low friction member 119a.

Next, the fastening mechanism 103 will be described. FIG.
9. As shown in FIGS. 21 to 23, the fastening mechanism 103 is externally fitted via a screwing mechanism 135 to the cylindrical portion 118 of the ratchet wheel 30A which is connected to the spline shaft portion 122 of the spindle shaft 102 so as to be relatively non-rotatable. It has a threaded ring member 130. This ring member 130 is
116, and is provided so as not to be rotatable relative to the winding drum 101 and to be relatively movable in the axial direction (left-right direction).

The screwing mechanism 135 includes a female screw 136 formed on the inner periphery of the ring member 130 and the ratchet wheel 3.
A male thread 137 formed on the outer periphery of the cylindrical portion 118 of 0A and screwed to the female thread 136 is formed. The male thread 137 of the cylinder 118 and the female thread 136 of the ring member 130 are formed as positive screws.
When the ring member 130 rotates relative to the cylindrical portion 118 in the direction indicated by the arrow A in FIG. 21, the ring member 130 moves rightward as indicated by the arrow B in FIGS. 19 and 22, and as shown in FIG.
Is in contact with the left end surface of the guide portion 119 of the ratchet wheel 30A, and the ring member 130 and the cylindrical portion 118 are integrated so that relative rotation is impossible.

In this fastening mechanism 103, in the event of a vehicle emergency, the amount of torsional deformation rotation of the knurled shaft portion 121 of the spindle shaft 102 with respect to the spline shaft portion 122 becomes a predetermined value at which the ring member 130 cannot be rotated. Spindle shaft
When the torsional deformation of the torsion bar portion 120 of the spindle shaft 102 reaches a predetermined value, the spline shaft portion 122 of the spindle shaft 102 and the winding drum 101 are connected to each other.
The ring member 130 and the ratchet wheel 30A are configured to be fastened via the ratchet wheel 30A so that they cannot rotate relative to each other.

Here, by the time the right end surface of the ring member 130 contacts the left end surface of the guide portion 119, the ring member 130 is
When the ring member 130 is assembled, the number of rotations that can rotate with respect to the
The ring member 130 can be easily set by rotating the ring member 130 by a desired number of rotations in a direction opposite to the above from a state where the right end surface of the ring member abuts on the left end surface of the guide portion 119. In this case, in order to prevent the ring member 130 from rotating easily,
118 is coated with resin.
It is desirable to apply a certain amount of frictional force during 130.

Next, the operation of the seat belt retractor 1A will be described. Note that the same operation as in the above embodiment will be briefly described. The load characteristics acting on the webbing W are also substantially the same as those in FIG. In the normal state, since the emergency lock mechanism 4 does not operate, the webbing W can be freely pulled out from the winding drum 101 and set on the waist, chest, or the like of the occupant sitting on the seat.

When the webbing W is set on the occupant's chest, waist, etc., in the event of a vehicle emergency such as a vehicle collision,
The emergency lock mechanism 4 locks the spline shaft portion 122 of the spindle shaft 102 so that it cannot rotate.
, The rotation of the winding drum 101 is also locked, and immediately thereafter, the intermediate portion of the webbing W extending from the winding drum 101 is clamped by the clamp mechanism 8. Thereafter, when the load acting on the webbing W increases and becomes equal to or greater than the first predetermined value F1, the webbing W clamped by the clamp mechanism 8 slides out against the sandwiching frictional force acting from the clamp members 91 and 92, and the energy increases. Is absorbed.

Thereafter, until the webbing W is fed out by L1 and the tightening of the webbing W is substantially completed, the webbing W is allowed to be pulled out by the clamp mechanism 8, energy is absorbed through friction, and the impact acting on the occupant is exerted. Is alleviated. Thereafter, when the load of the webbing W rises and becomes equal to or more than the second predetermined value F2, the torsion bar portion 120 of the spindle shaft 102 is torsionally deformed and energy is absorbed.

In this case, the torsion bar portion 120 of the spindle shaft 102 is torsionally deformed, and the knurled shaft portion 121 is moved relative to the locked spline shaft portion 122 of the spindle shaft 102.
Rotates together with the winding drum 101, and the webbing W is fed out. At this time, the ring member 130 that rotates together with the winding drum 101 moves rightward from the state of FIG. 19 through the state of FIG.

Normally, all the kinetic energy is absorbed until the amount of the webbing W extended reaches L2. However, if the amount of torsional deformation rotation of the torsion bar portion 120 of the spindle shaft 102 reaches a predetermined value, the right end surface of the ring member 130 comes into contact with the left end surface of the guide portion 119 as shown in FIG. And the ring member 130 is the ratchet wheel 3
0A, and the spline shaft 123 is connected to the winding drum 101 via the ratchet wheel 30A and the ring member 130.
To prevent the torsion bar portion 120 from breaking. In this way, the take-up drum 101 is completely restrained from rotating, the feeding of the webbing W is prevented, and the occupant is reliably restrained by the webbing W.

According to the seat belt retractor 1A, in the event of a vehicle emergency, the winding drum is
After the rotation of the webbing 100 is locked, the webbing W is first clamped by the
When a load equal to or more than the first predetermined value acts on the webbing W
To withdraw and absorb energy through friction,
Next, when a load equal to or more than the second predetermined value acts on the webbing W, the torsion bar portion 120 can be torsionally deformed to absorb energy.

In other words, while the energy is continuously absorbed by the clamp mechanism 8 via the friction of the webbing W,
Since the energy can be absorbed by torsionally deforming the torsion bar portion 120, there is no possibility that the load acting on the webbing W is reduced at all, as in the above-described embodiment.
Energy can be absorbed very efficiently and reliably.

Further, since the fastening mechanism 103 is provided, the amount of twist deformation rotation of the knurled shaft portion 121 of the spindle shaft 102 relative to the spline shaft portion 132 of the spindle shaft 102 in the webbing pull-out direction becomes a predetermined value after the operation of the emergency lock mechanism 4. Torsion of the torsion bar portion 120, and when the amount of rotation of the torsion deformation reaches a predetermined value, the spline shaft portion 122 of the spindle shaft 102 and the take-up drum 101 are fastened to each other so that they cannot rotate relative to each other. it can.

As a result, even when a large load acts on the webbing W in the event of a vehicle emergency, or when the spindle shaft 102 is repeatedly torsionally deformed by the vehicle colliding several times at a time,
In addition to absorbing the kinetic energy of the occupant, the breakage of the spindle shaft 102 is reliably prevented, and finally the occupant can be securely restrained by the webbing W, so that the occupant does not collide with the steering wheel, the front window, etc. It is possible to surely prevent the occupant and ensure the safety of the occupant. Other operations and effects similar to those of the above-described embodiment are exhibited.

Next, a modified example in which the first alternative embodiment is partially modified will be described. However, the same components as those of the above-described other embodiment will be described with the same reference numerals.

1] Modified Example 1—See FIG. 24 The seat belt retractor 1B cannot rotate relative to the female screw 141 formed on the winding drum 101B and the right end of the spindle 102 in the fastening mechanism 103B. A screwing mechanism 140 formed on the ratchet wheel 30B connected to the female screw part 141 and having a male screw part 142 screwed with the female screw part 141;
The ratchet wheel 30B is brought into contact with the winding drum 101B so that the spline shaft portion 122 of the spindle shaft 102 and the winding drum 101B are fastened via the ratchet wheel 30B.

The right flange 112 of the winding drum 101B has a fitting hole 143 formed at the center thereof, and a female screw 141 formed at the peripheral surface of the fitting hole 143.
A guide portion 144 is integrally formed with the guide portion 14B.
4, a male screw portion 142 is formed on the left side, so that the inner end surface of the fitting hole 143 and the left end surface of the guide portion 144 can be brought into contact with each other.

2] Modification 2—See FIG. 25 This seat belt retractor 1C is formed near the other end of the female screw 151 formed on the winding drum 101C and the spindle shaft 102C in the fastening mechanism 103C. A screw mechanism 150 having a male screw part 152 screwed to the female screw part 152,
The spindle shaft 102C and the ratchet wheel 30C are integrally formed, and a portion near the right end of the spindle shaft 102C and the winding drum
The take-up drum 101C is fastened to the vicinity of the right end of the spindle shaft 102C by abutting the take-up drum 101C.

The right flange 112 of the winding drum 101C has a fitting hole 153 formed at the center thereof, and a female screw 151 formed at the peripheral surface of the fitting hole 153. The right end of the spindle shaft 102C is formed. The guide part 154 is formed integrally with the
4, a male screw portion 152 is formed on the left side, so that the inner end surface of the fitting hole 153 and the left end surface of the guide portion 154 can abut.
The ratchet wheel 30C is formed integrally with the spindle 102C on the right side of the guide 154.

Next, a second alternative embodiment will be described.
In the second alternative embodiment, the shapes of the clamp members 91 and 92 of the clamp mechanism 8 of the above embodiment are changed.

In the clamp mechanism 8D of the second alternative embodiment, the movable clamp member 91D and the base clamp member 9
A pair of holding portions 160 and 165 which are long in the left and right direction are provided at both ends in the webbing passing direction (vertical direction) of the opposing surfaces of 2D, and a non-holding portion 169 is provided between the pair of holding portions 160 and 165. .

The lower holding portion 160 is provided with the movable clamp member 9.
A convex portion 161 formed in 1D and having a narrow width in the vertical direction, and a concave portion 162 formed in the base clamp member 92D and engaging with the convex portion 161. The upper clamping portion 165 is provided on the movable clamp member 91D. A concave portion 166 formed and narrowed in the vertical direction, and a convex portion 167 formed on the base clamp member 92D and engaging with the concave portion 161 are formed.
Very small protrusions are formed on the 167, the recesses 162, 166 and in the vicinity thereof.

That is, in the clamp mechanism 8D, the movable clamp member 91D and the base clamp member 9
A pair of holding portions 160 and 165 are provided at both upper and lower ends of 2D.
Since the non-clamping portion 169 is provided between the pair of clamping portions 160 and 165, a clamping force can be uniformly applied to the webbing W from the entire pair of clamping portions 160 and 165.
At 160 and 165, the webbing W is clamped by the engagement between the concave portions 162 and 166 and the convex portions 161 and 167, so that the performance of the clamping mechanism 8D can be improved, and the first predetermined value F1 can be easily set. According to the clamp mechanism 8D, energy is absorbed by each of the pair of holding portions 160 and 165, so that higher energy absorption can be performed than with a normal clamping mechanism.

When the clamp mechanism 8D is actually operated, the holding portions 160 and 165 hold the webbing W at the same time. When a load of the first predetermined value acts on the webbing W, first, the holding portion 165 on the drawing side is used. Allow the webbing W to be withdrawn, and the webbing portion of the non-clamping portion 169 is stretched to release friction and absorb energy. Then, when a second predetermined load is applied, the clamping portion 160 also moves the webbing W.
Withdrawal. Therefore, since the energy is absorbed by the two holding portions 160 and 165, the load does not concentrate on one of the holding portions, so that damage to the webbing W can be prevented.

The clamp mechanism 8D can be used in combination with the above-described embodiment and another embodiment, or can be used alone. When used alone, the emergency lock mechanism may be omitted so as not to restrict the rotation of the reel (rotary drum) in order to allow the webbing W to be pulled out.

The seat belt retractor according to the present invention is not limited to the one described in the above embodiment and another embodiment, and various modifications may be made without departing from the spirit of the present invention. It can be applied to a seat belt retractor.

[0101]

According to the seat belt retractor of the first aspect, it is possible to perform energy absorption by clamping the webbing in the middle of the webbing and adding frictional resistance to the webbing while allowing the webbing to be pulled out by the clamp mechanism. ,
At this time, the pinching force limiting mechanism limits the webbing pinching force of the clamp mechanism so that the load acting on the webbing does not increase beyond a predetermined value, so that energy absorption can be efficiently and reliably performed without applying a large load to the occupant. Can be done.

According to the seat belt retractor of the second aspect, the webbing can be pulled out while the frictional resistance is added to the webbing while clamping the webbing in the middle of the webbing by the clamp mechanism to perform energy absorption. Starts its operation later than the start of energy absorption by the clamp mechanism, and the energy absorption mechanism can perform energy absorption in parallel with the energy absorption by the clamp mechanism, so that the load acting on the webbing is reduced at all. There is no fear, and energy can be absorbed very efficiently and reliably.

According to the seat belt retractor of the third aspect, in the event of a vehicle emergency, after the rotation of the winding drum is locked by the emergency lock mechanism, first, a middle part of the webbing is clamped by the clamp mechanism, and the first webbing is attached to the webbing. When a load equal to or more than a predetermined value is applied, the webbing is allowed to be withdrawn and energy is absorbed through friction. Then, when a load equal to or more than the second predetermined value is applied to the webbing, the webbing of the ebbing and the winding drum is rotated. Energy can be absorbed by pressing the deformable member with the portion and deforming the deformable member in the diameter reducing direction.

That is, while the energy is continuously absorbed through the friction of the webbing by the clamp mechanism, the webbing and the body of the take-up drum sandwich the deformable member to deform the member in the diameter-reducing direction to absorb the energy. Therefore, there is no possibility that the load acting on the webbing is reduced at all, and the energy can be absorbed very efficiently and reliably. Further, other than the deformable member, no member for absorbing energy is required, and the operation of the clamp mechanism is simple as before, so that the structure can be simplified and downsized, and the manufacturing cost can be reduced. .

According to the seat belt retractor of the present invention, in the event of a vehicle emergency, after the rotation of the winding drum is locked by the emergency lock mechanism, first, a middle part of the webbing is clamped by the clamp mechanism, and the first webbing is fixed to the webbing. When a load equal to or more than a predetermined value is applied, the webbing is allowed to be pulled out and energy is absorbed through friction. Then, when a load equal to or more than the second predetermined value is applied to the webbing, the torsion bar is twisted. It can be deformed to absorb energy.

That is, the energy can be absorbed by torsionally deforming the torsion bar while the energy is continuously absorbed through the friction of the webbing by the clamp mechanism. There is no danger that the applied load will decrease at all, and energy absorption can be performed very efficiently and reliably. Further, other than the torsion bar, no member for energy absorption is required, and the operation of the clamp mechanism is simple as before, so that the structure can be simplified and downsized, and the manufacturing cost can be reduced. .

According to the seat belt retractor of the fifth aspect, the same effect as that of the third or fourth aspect is obtained, but the clamp mechanism prevents the load acting on the webbing from being increased from the first predetermined value by the clamp mechanism. In addition, since the webbing has a holding force limiting mechanism for limiting the webbing holding force, when a load equal to or more than the first predetermined value is applied to the webbing, the webbing is reliably pulled out by the clamp mechanism and energy is absorbed through friction. The first predetermined value can be set to a desired value by adjusting the webbing clamping force by the clamping force limiting mechanism.

According to the seat belt retractor of the sixth aspect, the same effect as in any one of the first to fifth aspects is obtained, but at least both end portions in the webbing passing direction of the opposing surfaces of both clamp members. Since a pair of holding portions is provided and a non-holding portion is provided between the holding portions, a clamping force can be uniformly applied to the webbing from the entire holding portion, and the performance of the clamping mechanism can be improved. It is easy to set the predetermined value. In addition, since the load applied to the webbing is distributed to both of the holding portions, the webbing can be prevented from being damaged without the load being concentrated on one of the holding portions.

According to the seat belt retractor of the seventh aspect, the same effect as that of the sixth aspect is obtained, but each holding portion is formed on one clamp member and has a concave portion having a narrow width in the webbing passing direction, and the other has a concave portion. Since the webbing is formed on the clamp member and is engaged with the concave portion, the webbing is clamped by the engagement between the concave portion and the convex portion in each of the holding portions. Can be further improved.

According to the seat belt retractor of the eighth aspect, the same effect as that of the first or second aspect is obtained. However, in a vehicle emergency, the rotation of the winding drum is locked by the emergency lock mechanism. Since the feeding of the webbing wound on the drum can be tolerated, energy can be reliably absorbed through the friction of the webbing by the clamp mechanism.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a seat belt retractor according to an embodiment of the present invention.

FIG. 2 is a right side view of the seat belt retractor.

FIG. 3 is an exploded perspective view of the emergency lock mechanism.

FIG. 4 is a perspective view of a winding drum.

FIG. 5 is an exploded perspective view of the winding drum.

FIG. 6 is a right side view of the winding drum left divided body.

FIG. 7 is a view taken in the direction of arrows VII-VII in FIG. 6;

FIG. 8 is a left side view of the winding drum right split body.

FIG. 9 is a view taken in the direction of arrows IX-IX in FIG. 8;

FIG. 10 is a partial sectional view of a winding drum.

FIG. 11 is a partial sectional view of a winding drum.

FIG. 12 is a diagram illustrating the operation of the seat belt retractor.

FIG. 13 is a diagram illustrating the operation of the seat belt retractor.

FIG. 14 is an operation explanatory view of the seat belt retractor.

FIG. 15 is an operation explanatory view of the seat belt retractor.

FIG. 16 is a diagram showing load characteristics acting on webbing.

FIG. 17 is an exploded perspective view of the seat belt retractor according to the first alternative embodiment.

FIG. 18 is a perspective view of a main part of the seat belt retractor.

FIG. 19 is a sectional view of a main part of the seat belt retractor.

20 is a sectional view taken along line XX-XX of FIG.

21 is a sectional view taken along line XXI-XXI in FIG.

FIG. 22 is a sectional view of a main part of the seat belt retractor.

FIG. 23 is a sectional view of a main part of the seat belt retractor.

FIG. 24 is a sectional view of a seat belt retractor according to a modification of the first alternative embodiment.

FIG. 25 is a sectional view of a seat belt retractor according to a modification of the first alternative embodiment.

FIG. 26 is a side view of a clamp mechanism according to a second different embodiment.

FIG. 27 is a view taken in the direction of arrows XXVII-XXVII in FIG. 26;

FIG. 28 is a view taken in the direction of the arrows XXVIII-XXVIII in FIG. 26.

[Explanation of symbols]

 W Webbing 1, 1A to 1C Seat belt retractor 4 Emergency lock mechanism 5, 101, 101B, 101C Winding drum 6 Deformation member 8, 8D Clamp mechanism 51, 61 Body 95 Nipping force limiting mechanism 91, 91D Movable clamp member 92, 92D Base clamp member 102 Spindle shaft (torsion bar) 160,165 Holding part 169 Non-holding part 161,167 Convex part 162,166 Concave part

Claims (8)

[Claims] In a vehicle emergency, a clamp mechanism is provided for clamping the webbing in the middle of the webbing and adding frictional resistance to the webbing while allowing the webbing to be pulled out to absorb energy, and the clamp mechanism has a load acting on the webbing. A clamping force limiting mechanism for limiting the webbing clamping force of the clamp mechanism so that the seat belt retractor does not increase beyond a predetermined value. 2. A clamp mechanism for sandwiching a middle portion of a webbing in a vehicle emergency and adding a frictional resistance to the webbing while allowing the webbing to be pulled out to absorb energy, and being delayed from the start of energy absorption by the clamp mechanism. And an energy absorbing mechanism for starting operation and absorbing energy in parallel with energy absorption by the clamp mechanism. A take-up drum for taking up the webbing; an emergency lock mechanism for locking the rotation of the take-up drum in the event of a vehicle emergency; a webbing that clamps a middle portion of the webbing in conjunction with the locking operation of the emergency lock mechanism; When a load equal to or more than a first predetermined value is applied to the webbing, a clamp mechanism that allows the webbing to be pulled out and absorbs energy through friction, and a winding mechanism that is positioned inside the webbing wound around the winding drum. It is provided on the outer peripheral side of the body of the taking drum,
When a load greater than a second predetermined value greater than the first predetermined value is applied to the webbing, a deformable member that is nipped by the webbing and the body of the winding drum and deforms in the diameter reducing direction to absorb energy. Seat belt retractor with,. A winding drum for winding the webbing; an emergency lock mechanism for locking the rotation of the winding drum in a vehicle emergency; When a load equal to or greater than the first predetermined value is applied, the clamp mechanism allows the webbing to be pulled out and absorbs energy through friction. Is a torsion bar that rotates integrally with the winding drum, and when a load greater than a second predetermined value greater than the first predetermined value acts on the webbing, the torsion bar performs torsional deformation to absorb energy. And a seat belt retractor comprising: 5. The clamping mechanism according to claim 1, wherein the clamping mechanism has a clamping force limiting mechanism for limiting a webbing clamping force such that a load acting on the webbing does not increase beyond a first predetermined value. 5. The seat belt retractor according to 3 or 4. 6. The clamping mechanism has a pair of clamping members opposed to each other with a webbing interposed therebetween, and a pair of clamping portions at at least both end portions in the webbing passing direction of opposed surfaces of both clamping members. The seat belt retractor according to any one of claims 1 to 5, wherein a non-clamping portion is provided between the clamping portions. 7. Each of the holding portions includes a concave portion formed on one of the clamp members and having a narrow width in the webbing passing direction, and a convex portion formed on the other clamp member and engaging with the concave portion. The seat belt retractor according to claim 6, wherein: 8. An emergency lock mechanism for locking the rotation of the winding drum in a vehicle emergency, and a pay-out permitting means for allowing the webbing wound on the winding drum to be fed in a vehicle emergency. The seat belt retractor according to claim 1 or 2, wherein: