JPH11227566A - Seat belt retractor with pretensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive seat belt retractor with pretensioner having an excellent clutch mechanism capable of increasing the degree of freedom of the arrangement of pretensioner component parts and also capable of rotating a winding shaft efficiently and smoothly in a webbing winding direction. SOLUTION: A clutch outer ring 12 which is supported relatively rotatably on a sleeve 14 connected to a winding shaft 4 and rotated drivingly by a driving means comprises a cam surface 12b forming a generally wedge-shaped space between the outer ring and the outer peripheral surface of the sleeve 14 and a roller pin 10 movable in the wedge-shaped space in a sleeve engaging direction. At the time of emergency of a vehicle, a retainer 8 fixed to an inertia plate 6 which is disposed relatively rotatably on a base side wall 11a causes a delay in rotation relative to a drivingly rotated clutch outer ring 12 so that the roller pin 10 is engaged with the outer peripheral surface of the sleeve 14 and the cam surface 12b.

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 having a pretensioner for removing slack of a seat belt by winding webbing around a winding shaft of the retractor in an emergency.

[0002]

2. Description of the Related Art Conventionally, a seatbelt device for holding a vehicle occupant or the like safely in a seat tends to reduce a retracting force of a webbing by a retractor in order to reduce a feeling of wearing the webbing by the occupant. However, if a large force is applied at the time of a collision, the play of the webbing is inevitably increased, and the restraint is delayed due to the play of the webbing, and there is a possibility that the occupant cannot be effectively and safely restrained.

[0003] In order to remove the slack of the webbing by pulling the webbing in tension in an emergency,
There is a type in which a pretensioner that instantaneously rotates a winding shaft of a retractor in a winding direction is incorporated in a seat belt device. When such a pretensioner is incorporated in a retractor, the rotation driving member for transmitting the driving force of the driving means to the winding shaft and rotating the same should not interfere with the rotation of the winding shaft during normal use. When the pretensioner is not operating, the rotation driving member is disengaged from the winding shaft.When the pretensioner is operating, the rotation driving member is connected to the winding shaft to transmit rotation torque to the winding shaft. Various clutch mechanisms are provided between the take-up shaft and the take-up shaft.

[0004] For example, a pretensioner disclosed in Japanese Patent Application Laid-Open No. 57-128169 is a pull member attached to a casing by a mooring device (clutch mechanism) so as to be disengaged from a belt shaft (winding shaft). When the energy storage device (drive means) is actuated in an emergency such as a vehicle collision, the pulling member roller overcomes the mooring force of the mooring device and is connected to the belt shaft. The shaft is tightened and rotated.

That is, during normal use, the rotation drive member is mounted in a state disengaged from the take-up shaft by the clutch mechanism, so that it does not interfere with the rotation of the take-up shaft.
Then, when the driving means is operated to rotate the rotary drive member in an emergency such as a vehicle collision, the rotary drive member is connected to the winding shaft via a clutch mechanism, and the winding shaft is integrally wound. Since the webbing is rotated, the webbing is wound and slack is removed.

[0006]

Incidentally, in a clutch mechanism such as a pretensioner disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-128169, for example, a rolling element is connected between a rotary drive member and a winding shaft. It is arranged as a member,
The rolling element takes a connected state in which the rolling element is engaged with the winding shaft and a released state in which the rolling element is not engaged. During normal use, the rolling element is disengaged from the winding shaft by holding means such as an elastic member interposed between the rotary driving member and a fixing member fixed to the retractor base side plate. Will be retained.

However, in the structure of the holding means in which an elastic member such as a spring member is interposed between the rotary driving member and the rolling element as described above, it is difficult to assemble a small spring member.
There is a problem that the assemblability is not good. In a configuration in which a fixing member such as a shearing pin is fixed to the retractor base side plate as a holding means, and the rolling element is held in a non-engagement with the winding shaft by the fixing member, a clutch mechanism for the retractor base side plate is inevitably provided. (Particularly, the rotational phase around the winding shaft) is determined. Therefore, there is a problem that the arrangement of the components of other pretensioner components is also restricted, so that the degree of freedom in design is reduced, and high assembling accuracy is required when assembling the clutch mechanism, resulting in an increase in manufacturing cost. is there.

Further, when the pretensioner is started, a fixing member such as a shear pin for supporting the rolling element is deformed.
Although shearing must be performed, the starting resistance is large, and a large driving force is required to deform and shear the stationary member with the rotary driving member in a stationary state. Therefore, when the rotary driving member is driven to rotate by a driving means having a large driving force, the fixing member is sheared instantaneously. However, since the fixing member is sheared before the clutch mechanism is connected, rebound due to impact is caused. There is a possibility that the engagement of the clutch mechanism is not constant due to the fluctuation of the belt tension.

In view of the foregoing, an object of the present invention is to solve the above-described problems, and to improve the degree of freedom in arranging components of a pretensioner component, and to efficiently and smoothly rotate a winding shaft in a webbing winding direction. It is an object of the present invention to provide an inexpensive retractor for a seat belt with a pretensioner, which is provided with a good clutch mechanism capable of performing the above-mentioned operation.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide a retractor for a seat belt provided with a pretensioner for rotating a winding shaft of the retractor in a vehicle emergency in a direction in which the slack of the seat belt is removed. A rotation drive member rotatably supported by the drive means and supported rotatably about the axis with respect to the sleeve connected to the winding shaft has a substantially wedge-like shape between the sleeve and the outer peripheral surface of the sleeve. A cam surface forming a space, and a meshing element disposed in the wedge-shaped space and movable in a sleeve engaging direction, and holding the meshing element in a disengaged state with the sleeve. The holding means, which is arranged to be rotatable relative to the retractor base, causes a rotation delay with respect to the rotary drive member which is driven to rotate at the time of a vehicle collision. To be achieved by the retractor for a seat belt with pretensioner, characterized in that engaging the engagement element on the cam surface.

Preferably, the holding means includes a holding piece for preventing the engagement element from moving in the clutch ring engaging direction, and the holding means is provided when a rotation acceleration of a predetermined value or more is applied to the holding piece by a rotation driving member. An inertial substrate having an inertial mass sufficient to cause a rotation delay with respect to the rotary drive member.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 3 are exploded perspective views of a main part of a seat belt retractor 1 with a pretensioner according to an embodiment of the present invention. FIGS. 4 and 5 show the seat with a pretensioner shown in FIGS. It is principal part sectional drawing of the retractor 1 for belts.

As shown in FIGS. 1 to 3, the seat belt retractor 1 with a pretensioner is provided with a take-up reel 7 on which webbing is wound or pulled out. Similarly, the take-up reel 7 is constantly urged in a direction in which the webbing is taken up by a known take-up spring device (not shown) connected to the take-up shaft 4. If the webbing is to be pulled out with an acceleration equal to or greater than a predetermined value, the emergency lock mechanism 2
As a result, the rotation of the winding shaft 4 is prevented, and the webbing is not pulled out any more.

Further, in the seat belt retractor 1 with a pretensioner, the slack of the seat belt is removed by using the winding shaft 4 on one of the base side walls 11a of the retractor base 11 formed in a substantially U-shape. A pretensioner 3 provided with a driving means 20 for rotating in the direction is provided (see FIG. 4). The pretensioner 3 includes a clutch outer ring 12 which is a rotation driving member disposed rotatably around a sleeve 14 fitted to one end of the winding shaft 4 penetrating the base side wall 11a, and a gas generator. A drive means 20 for rotationally driving the clutch outer ring 12 by a pinion gear 21 always meshed with a rack 25 pressed and driven by a gas pressure generated by a gas pressure 29. The vehicle includes a planetary gear device 35, which is a speed increasing gear transmission device disposed between the pinion gear 21 and the clutch outer ring 12, and a control device (not shown) for operating the gas generator 29 at the time of a vehicle collision.

The clutch outer ring 12 is a cylindrical member which is driven to rotate by a driving means 20 via a planetary gear unit 35 which will be described later. A sun gear meshing with the planetary gear 15 of the planetary gear unit 35 is formed on the outer peripheral surface. External teeth 12
a is formed, and a wedge-shaped space is formed between the outer peripheral surface of the sleeve 14 and the inner peripheral surface which is thinned so as to have an inner diameter larger than the outer diameter of the sleeve 14.
The two cam surfaces 12b are formed at equal intervals along the circumferential direction.

In each of the wedge-shaped spaces, a cylindrical roller pin 10 which is a meshing element movable in a clutch ring engaging direction so as to enable torque transmission between the clutch outer ring 12 and the sleeve 14; The roller pin 10
The roller pin holding pieces 9a and 9b of the retainer 8 for holding the roller pin in a disengaged state with the sleeve 14 are provided.

The retainer 8 is shown in FIGS.
As shown in FIG.
a) a substantially disk-shaped substrate portion 8a having a circular hole through which the winding shaft 4 supported by the base member 8a is inserted, and four pairs of holding pieces bent and formed to extend along the axial direction of the substrate portion 8a. Elastic holding pieces 9a and 9b, and four locking claw portions 8b protruding at equal intervals from the outer peripheral edge of the substrate portion 8a are locked in the groove portions 6a of the inertia plate 6. By
It rotates integrally with the inertia plate 6.

Therefore, holding means for holding the roller pin 10 in a disengaged state with the sleeve 14 and rotatably disposed relative to the base side wall 11a comprises the inertia plate 6 and the retainer 8. The distal ends of the elastic holding pieces 9a and 9b are inserted into the respective wedge-shaped spaces of the clutch outer ring 12 disposed outside the retainer 8, and the roller pin 1
0 is disengaged from the outer peripheral surface of the sleeve 14.

The retainer 8 is made of a synthetic resin such as polyacetal or nylon, or a metal material such as aluminum, zinc, stainless steel, or a thin plate spring material of a steel plate. The elastic holding pieces 9a and 9b can be easily deformed. It must be a material. The inertia plate 6 as an inertial substrate is formed of, for example, a synthetic resin material having an increased specific gravity by mixing metal powder, and has a center hole supported by the bush 13 so as to be relatively rotatable, and an outer peripheral portion. Are mounted so as to be in sliding contact with the flat plate portion of the holder 5 fixed to the base side wall 11a and to be able to rotate relative to the base side wall 11a.

The retainer 8, which is rotatable integrally with the inertia plate 6, is rotated from the cam surface 12b of the clutch outer ring 12 at the time of assembling the pretensioner via the roller pin 10 held between the elastic holding pieces 9a, 9b. When the force is received, it can rotate relative to the base side wall 11a. That is, each roller pin 10 constituting the clutch mechanism can be displaced around the winding shaft 4 in accordance with the mounting position of the clutch outer ring 12, and is automatically disposed at a predetermined position in the wedge-shaped space. Therefore, the mounting position of the clutch outer ring 12 with respect to the base side wall 11a is not determined.

Therefore, the degree of freedom in arranging the other pretensioner components increases, and the degree of freedom in designing the retractor increases. Further, since the assembling accuracy at the time of assembling the clutch mechanism is relaxed, the assembling becomes easy, and the dimensional variation of the components can be absorbed, so that the manufacturing cost can be reduced.

On the other hand, at the time of a vehicle collision, the retainer 8
When a rotational acceleration of a predetermined value or more is received from the clutch outer ring 12 via the roller pins 10 sandwiched between the elastic holding pieces 9a and 9b, the clutch outer ring 12 is driven to rotate by the inertia mass of the retainer 8 itself and the inertia plate 6. Can cause a rotation delay. Therefore,
(In FIG. 1, the direction of arrow X ₁₎ webbing winding direction to the clutch outer ring 12 by later-described drive unit 20 when a predetermined or more rotational acceleration occurs, the clutch outer ring 12 is a predetermined angle arrow against the retainer 8 rotate relative to the X ₁ direction, to urge the roller pin 10 to the take-up shaft center direction by the cam surface 12b.

At this time, since the elastic holding pieces 9a and 9b are easily deformed so as not to hinder the movement of the roller pin 10 in the biting direction, the roller pin 10 is connected to the cam surface 12b of the clutch outer race 12 and the sleeve. The sleeve 14 and the clutch outer ring 12 are connected to each other by biting between the outer peripheral surface of the clutch 14 and the clutch outer ring 12, and the rotational torque of the clutch outer ring 12 is transmitted to the winding shaft 4. The sleeve 14 is made of a material harder than the roller pin 10, and the outer peripheral surface thereof is subjected to knurling (knurled knurling) for facilitating biting, shot peening, spline processing, and the like.

When the clutch outer ring 12 is further driven to rotate in the webbing winding direction, the roller pin 10 biting into the sleeve 14 rotates together with the clutch outer ring 12 in the webbing winding direction, but the base side wall 11a. The elastic holding pieces 9a and 9b of the retainer 8 rotatable with respect to the outer ring 12 can be integrally rotated together with the clutch outer ring 12 in the webbing winding direction.
Of course, at this time, the elastic holding pieces 9a and 9b may be configured to be broken from the substrate 8a. That is, a clutch mechanism is formed between the sleeve 14 and the clutch outer ring 12 by the cam surface 12b of the clutch outer ring 12, the inertia plate 6, the retainer 8, the roller pin 10, and the like.

As shown in FIGS. 2 and 5, the planetary gear unit 35 includes internal teeth 16a of the planetary gear case 16 fixed to the outside of the base side wall 11a and the clutch outer ring 1 as shown in FIGS.
2 and a rotating disk 17 which is a carrier member for rotatably supporting each of the planetary gears 15. The rotary disk 17 has a through hole 17a into which a pin 19 for rotatably supporting the planetary gear 15 is press-fitted, and a central hole 1 into which a pinion gear 21 is fitted.
8 are formed, and the planetary gear 15 is connected to the pinion gear 2.
It is revolved by a rotating disk 17 that rotates integrally with 1. Therefore, the clutch outer ring 12 is
By the rotation of 1, the rotation is accelerated.

As shown in FIGS. 3 and 4, the drive means 20 includes a rack 25 having rack teeth 25a meshed with the pinion gear 21, a cylinder 24 for movably receiving the rack 25, The cylinder 24
And a cap 28 for fixing a gas generator 29 at the distal end of the rack gear case 22 fixed to the outside of the planetary gear case 16.
It is connected to. The rack gear case 22 has a central opening 3 in which the pinion gear 21 is rotatably housed.
3 and a guide portion 34 that slides and guides the rack 25 in partial communication with the central opening 33. An opening 23 a through which the tip of the winding shaft 4 penetrates outside the rack gear case 22. Is disposed to cover the pinion gear 21 and the rack 25.

At the end of the rack 25 on the gas generator 29 side, a piston 27 slidable in the cylinder 24 together with a cushioning material 26 made of a material such as synthetic resin, rubber, or foamed metal is provided. The high-pressure gas generated by the gas generator 29 is transmitted to the piston 27 via the cylinder 24. Further, depending on the design, the cushioning material is not required, and the piston and the rack can be manufactured integrally. Further, it is also possible to obtain an effect of gas sealing by using an O-ring for the cushioning material.

Next, the operation of the clutch mechanism in the seat belt retractor 1 with a pretensioner will be described. In the normal running state of the vehicle, the clutch outer ring 12 and the roller pin 10 are not engaged with the sleeve 14 as shown in FIG. When the above-described driving means 20. pretensioner is activated when the vehicle collision to rotate the clutch outer race 12 in the arrow X ₁ direction, the retainer 8, roller pin 1 which is sandwiched elastic holding pieces 9a, 9b,
0, the clutch outer ring 12 receives a rotational acceleration of a predetermined value or more.

Then, the retainer 8 has a rotational delay with respect to the clutch outer ring 12 that is rotationally driven due to the inertia mass of the retainer 8 itself and the inertia plate 6. As a result, the roller pin 10 is urged toward the center of the winding shaft by the cam surface 12b as shown in FIG. At this time, the elastic holding pieces 9a, 9b of the retainer 8 are
Until the roller pin 10 reliably bites between the outer peripheral surface of the sleeve 14 and the cam surface 12b, the holding piece can be moved toward the center of the winding shaft by elasticity or plastic deformation.

Then, as shown in FIG. 9, when the roller pin 10 is moved to a position where the roller pin 10 bites between the outer peripheral surface of the sleeve 14 and the cam surface 12b, the clutch outer race 12
Is transmitted to the sleeve 14, and these sleeves 14
And roller pin 10 rotates integrally with the direction of arrow X ₁ and the clutch outer ring 12, since rotating the winding shaft 4 in a direction to wind up the webbing, the webbing is tightened, the play of the seat belt is removed.

At this time, the elastic holding pieces 9a, 9b of the retainer 8, which can rotate relative to the base side wall 11a,
The rotation to the clutch outer ring 12 integrally webbing winding direction together, but with respect to the roller pin 10 to move in the direction of arrow X ₁ can be imparted to the inertial resistance and the retainer 8 itself by the inertia plate 6.

Accordingly, in the clutch mechanism of the seat belt retractor 1 with the pretensioner of the above-described embodiment, even if the roller pin 10 biting between the sleeve 14 and the clutch outer ring 12 comes off once for any reason, The roller pin 10 can always be engaged between the sleeve 14 and the clutch outer ring 12 even when the driving force is greatly changed, for example, immediately after the operation of the driving means 20, because the clutch outer ring can be engaged immediately. 12 can be reliably transmitted to the sleeve 14.

Further, the roller pin 10 is
The retainer 8 which is held in a disengaged state with respect to
It is disposed so as to be rotatable relative to the base side wall 11a together with the inertia plate 6, and it is not necessary to deform or shear a fixing member such as a shear pin when the pretensioner is started and the clutch mechanism is connected. The starting resistance of the rotary drive member at the time of starting the pretensioner can be reduced, and the impact of the clutch connection can be reduced by gently engaging the roller pin 10.

Therefore, the time delay from the start of the pretensioner to the start of the webbing wrapping can be reduced, and the roller pin 10 does not bite poorly due to rebound or belt tension fluctuation due to the impact of the clutch connection. Further, when the clutch mechanism is connected, an excessive impact load is not applied to each mechanism portion, and the winding shaft 4 can be efficiently and smoothly rotated in the webbing winding direction.

Incidentally, the structure of the retractor, the pretensioner, and the like in the present invention is not limited to the structure of the above embodiment, and it goes without saying that various forms can be adopted. Further, the configurations of the sleeve, the meshing element, the cam surface of the rotary drive member, the holding means, and the like that constitute the clutch mechanism can be appropriately changed. For example, although a cylindrical roller pin has been described in the above embodiment as a meshing element, a spherical meshing element may be used.
Further, in the above embodiment, the holding means for holding the meshing element in a disengaged state with the sleeve and being rotatably disposed relative to the retractor base is constituted by the inertia plate 6 and the retainer 8. However, these retainers and the inertia plate may be integrally formed.

[0036]

According to the retractor for a seat belt with a pretensioner of the present invention, the holding means for holding the meshing element constituting the clutch mechanism in a state disengaged from the sleeve connected to the winding shaft, Since it is arranged to be rotatable relative to the tractor base, each meshing element can be displaced around the winding axis according to the mounting position of the rotary drive member, and automatically moves to a predetermined position in the wedge-shaped space. It is arranged in. Therefore, the mounting position of the rotary drive member with respect to the retractor base is not determined, so that the degree of freedom in designing the retractor is increased, the assembly of the clutch mechanism is facilitated, and the manufacturing cost can be reduced.

Further, the holding means does not need to deform and shear the fixed member when the pretensioner is started and the clutch mechanism is connected, so that the starting resistance of the rotary drive member at the time of starting the pretensioner can be reduced. In addition, the engagement element can be gently engaged to reduce the shock of the clutch connection. Therefore, the time delay from the start of the pretensioner to the start of the webbing wrapping can be reduced, and the poor engagement of the meshing element can be prevented. Further, when the clutch mechanism is connected, an excessive impact load is not applied to each mechanism portion, and the winding shaft can be efficiently and smoothly rotated in the webbing winding direction. Therefore, while improving the degree of freedom in the arrangement of the pretensioner components, the inexpensive seatbelt with a pretensioner having a good clutch mechanism capable of efficiently and smoothly rotating the winding shaft in the webbing winding direction. Can provide a retractor.

[Brief description of the drawings]

FIG. 1 is a partial exploded view of a main part of a seat belt retractor with a pretensioner according to an embodiment of the present invention.

FIG. 2 is an exploded view of a main part of the retractor for a seat belt with a pretensioner shown in FIG.

3 is an exploded view of a main part of the retractor for a seat belt with a pretensioner shown in FIG.

4 is a cross-sectional view of a main part of the seat belt retractor with a pretensioner shown in FIG. 3;

FIG. 5 is a cross-sectional view of a main part of the seat belt retractor with a pretensioner shown in FIG. 2;

FIG. 6 is an enlarged view of a main part of the clutch mechanism shown in FIG. 5;

7 is a cross-sectional view of the clutch mechanism shown in FIG. 6 taken along the line AA.

FIG. 8 is a partially enlarged view for explaining an operation state of the clutch mechanism shown in FIG. 6;

FIG. 9 is a partially enlarged view for explaining an operation state of the clutch mechanism shown in FIG. 6;

[Description of Signs] 1 Retractor for seat belt with pretensioner 3 Pretensioner 4 Take-up shaft 6 Inertia plate 8 Retainer 9a Roller pin holding piece 9b Roller pin holding piece 10 Roller pin 11 Retractor base 12 Clutch outer ring 14 Sleeve 20 Drive Means 29 Gas generator

Claims (1)

[Claims] 1. A retractor for a seat belt, comprising: a pretensioner for rotating a retracting shaft of a retractor in a direction in which a slack of a seat belt is removed in a vehicle emergency, wherein the sleeve is connected to the retracting shaft. A cam surface defining a substantially wedge-shaped space between the sleeve and the outer peripheral surface of the sleeve; A meshing element disposed in the space and movable in a sleeve engaging direction, the meshing element being held in a disengaged state with the sleeve, and being rotatable relative to a retractor base. The provided holding means causes a rotation delay with respect to the rotation driving member that is rotated at the time of a vehicle collision,
A retractor for a seat belt with a pretensioner, wherein the engaging element is engaged with an outer peripheral surface of a sleeve and a cam surface.