JP3252170B2 - Rotary actuator actuated pretensioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretensioner for a seat belt device, and more particularly, to a rotor seal structure of a gas-pressure operated rotary actuator constituting a driving portion thereof.

[0002]

2. Description of the Related Art A pretensioner in a seatbelt device of a vehicle or the like is provided to tighten a loosely mounted belt in an emergency such as a vehicle collision, thereby restraining an occupant's body to a seat and enhancing the function of the seatbelt. There are various operating mechanisms. Among them, in particular, as a typical example of a type in which a driving unit is a rotary actuator, a rotor with vanes is rotated by gas pressure in a cylinder, and thereby a seat belt take-up reel is rotationally driven, conventionally, there is a conventional type. There is a technique disclosed in Japanese Patent Publication No. 59-15657. Further, as an example in which a vane is movable with respect to a rotor in a similar one, German Patent Publication No. 250562
No. 6 discloses a technique disclosed in the specification.

[0003]

However, unlike an actuator of a direct acting type, in which a stroke can be set by a cylinder length, in order to obtain a desired pretensioning stroke with less than one rotation of the rotor, an initial operation is required. It is important to increase the rotor acceleration of the gas generator. To achieve this, it is necessary to effectively capture the high gas pressure immediately after the operation of the gas generator on the vane pressure receiving surface. Easy to get out of gaps. Therefore, in order to prevent this, the working accuracy of the cylinder and the vane must be extremely high to reduce the gap between the two, or the gap must be sealed with precise sealing means. However, such measures are impractical in view of manufacturing costs, dimensions, and the like.

The present invention has been devised in view of the above circumstances, and in a pretensioner using a rotary actuator as a driving means, a cylinder is provided by a simple sealing means by utilizing gas pressure as a driving source. It is an object of the present invention to seal the space between the rotor and the rotor, effectively apply gas pressure to the pressure receiving surface of the vane, and secure a printing stroke.

[0005]

Means for Solving the Problems In order to solve the above problems, the present invention comprises a gas generator and an actuator that winds a seat belt using gas supplied from the gas generator as a driving source. A cylinder formed with a working chamber communicating with the gas generator, and disposed in the working chamber rotatably supported by the cylinder, and cooperating with a partition formed in the cylinder to form the working chamber. In a rotary actuator operating pretensioner including a rotor having a vane partitioned into a pressurizing chamber communicating with a gas generator and a back pressure chamber opened to the atmosphere, a seal member is provided on the pressurizing chamber side of the vane, The sealing member is a flexible lip pressed against the cylinder by the pressure of the gas supplied to the pressurizing chamber along the periphery thereof. And a hook that extends toward the back pressure chamber
The lip has a tip side facing the pressure chamber side.
And the tip edge of the cylinder
And the hook is engaged with the vane of the rotor .

[0006]

In the rotary actuator operating pretensioner according to the present invention having such a configuration, the flexible lip of the seal member attached to the pressure chamber side of the vane causes the peripheral edge of the seal to be provided to the pressure chamber. The cylinder is pressed against the cylinder with a strength corresponding to the pressure of the supplied gas, and functions to prevent gas leakage from the pressurizing chamber to the back pressure chamber. Then, the tip end of the lip is widened toward the pressure chamber side, by which is elastically contacted the leading edge to the cylinder by self-elasticity, because between the vanes of the peripheral edge and the cylinder is sealed from the beginning, In particular, the function of preventing gas leakage from the pressurized chamber to the back pressure chamber at the beginning of gas pressure supply is improved. Further, the seal member has a hook extending in the direction of the back pressure chamber, and the hook is locked to the vane of the rotor .
Thus, when the seal member is assembled to the vane, the hook performs the positioning function, and it is possible to avoid a decrease in the sealing function due to a shift in the mounting position.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the rotary actuator operation pretensioner includes a gas generator 4,
An actuator 3 that winds a seat belt by using a gas supplied from the gas generator 4 as a driving source. The actuator includes a cylinder housing 30 in which an operating chamber 301 communicating with the gas generator 4 is formed and a cylinder that covers an opening surface thereof. A cylinder comprising a lid and
A pressurizing chamber 301a and an exhaust hole 307 which are rotatably supported by the housing 30 and disposed in the working chamber 301 and cooperate with a partition wall 303 formed in the housing 30 to communicate the working chamber 301 with the gas generator 4. And a rotor 31 having a vane 311 partitioned into a back pressure chamber 301b that is open to the atmosphere. Then, the pressurizing chamber 301 of the vane 311
A seal member 33 is provided on the side a. As shown in an enlarged manner in FIG. 2, the seal member 33 is moved along the periphery of the cylinder 3 by the pressure of the gas supplied to the pressurizing chamber 301 a.
It has a flexible lip 331 pressed against zero.

As shown in FIG. 3, the pretensioner in this example uses a retractor R as a seat belt wrapping means.
One end of the retractor R is riveted and supported by a frame 10 of the retractor R, and the other end of the actuator 3 is mounted with a winding spring unit 12 of the retractor R. Further, a clutch means for engaging and disengaging the actuator 3 and the seat belt winding shaft 2 of the retractor R is provided. The clutch means includes a ratchet wheel 21 provided on the seat belt winding shaft 2 and a clutch key 22 provided on the rotor 31 side.

The ratchet wheel 21 has a retractor R
Of the ratchet wheel 21 and the outer teeth 211 of the ratchet wheel 21 are formed on the take-up reel 1.
And is prevented from rotating with respect to the shaft 2. In the drawings, reference numeral 13 denotes a lock pawl rotatably supported by a reel flange of the retractor R, and 101 denotes ratchet internal teeth on the frame 10 side with which the reverse pawl is engaged.

Further, each part of the pretensioner will be described in detail with reference mainly to FIG. First, the housing 30 is open at one end, and has a working chamber 301 surrounded by a cylindrical peripheral wall and an end wall. Similarly, the housing 30 is also opened at one end, and is surrounded by an arch-shaped enclosure and an end wall. Working chamber 3
A working chamber 301 is formed into a substantially cylindrical space in cooperation with a lid 32 closing an end face opening of the working chamber 301.

The working chamber 301 and the supply chamber 302 of the housing 30 communicate with each other through a groove 300 formed in a portion of the housing wall where the working chamber 301 and the supply chamber 302 face each other, and the groove 300 forms a through hole connecting the two chambers. The housing 30 has a partition wall 303 extending radially inward from the peripheral wall in contact with the groove 300.
Are formed. A concave portion 304 is provided at the tip of the partition wall 303.
Is formed, and this is used as a housing support portion of the seal member 34 described later. Further, a seal groove 305 is formed around the outer periphery of the working chamber 301 and the supply chamber 302, and six screw holes 309 in this example are arranged outside the seal groove 305 at appropriate intervals. Has been established. This screw hole 309 is code | symbold as the screw through hole 321 of the lid 32, and the fastening screw 3 which fixes the lid 32 to the housing 30 is used.
9 for screwing. Further, an annular support flange 306 protruding from an end wall so as to surround a shaft hole of the working chamber 301 and an exhaust hole 307 for opening the working chamber 301 to the outside of the housing 30 are formed.

The rotor 31 defines an engagement space surrounding the outer periphery of the ratchet wheel 21 in the inner periphery of the working chamber 301, and includes a ring portion 312, which constitutes a rotation support portion of the rotor 31 to the housing 30, and a ring portion. There is provided a vane 311 functioning as a pressure receiving portion extending in a radial direction from 312. The inner circumference of the ring portion 312 is a stepped hole whose diameter is enlarged at both ends. Behind the vane 311, a rectangular cylindrical key sliding hole 313 into which the clutch key 22 is inserted is formed. Further, a pair of notches 314 are formed at both corners of the tip of the vane 311.

The sealing member 33 according to the subject of the present invention includes:
It is composed of a flexible plastic material such as nylon.
The seal member 33 has an attachment portion 330 having a shape substantially corresponding to the shape of the pressure receiving surface of the vane 311, and a mutually continuous seal lip 331 rising from three peripheral edges except for an edge portion in contact with the rotor ring portion 312. Among these lips 331, those that come into contact with the peripheral wall of the working chamber 301 are as follows:
In the figure, it is not shown because it is located on the back side of the attachment part 330. As shown in an enlarged manner in FIG.
31 has its front end side expanded toward the pressurizing chamber 301a by a predetermined angle α. This is a configuration in which the sealing lip 331 is made to resiliently contact the leading edge 331 a with the cylinder, that is, the housing 30 and the lid 32 by its self-elasticity by assembling the sealing member 33 to the vane 311. These seal lips 331
At the time of one rotation, the pressure between the both ends (one end surface is the inner end surface of the lid 32) and the peripheral surface of the working chamber 301 is pressed by the gas pressure to perform the function of sealing the gap between the housing 30 and the vane 311.

Further, the seal member 33 is formed with a hook 332 projecting in the direction of the back pressure chamber, that is, in the direction opposite to the direction in which the lip 331 stands up. The hook 332 constitutes a locking means that is locked by the notches 314 formed at both corners of the tip of the vane 311 of the rotor 33. The hook 332 is used when the seal member 33 is attached to the vane 311. 332
Are positioned to perform a function of avoiding a decrease in the sealing function due to a shift in the mounting position.

The clutch key 22 includes a pressure receiving head 221 that receives gas pressure and a wedge-shaped pawl 222 that constitutes means for engaging the ratchet wheel 21. The pawl 222 is disposed toward the ratchet wheel 21. You. The key connector 23 is locked to the pressure receiving head 221 of the clutch key 22. This is the clutch key 22
And a function of controlling the supply of the gas pressure from the supply chamber 302 to the working chamber 301 when it is not operated. Dovetail groove 231
And an engagement hook 232 for the opening of the groove 300.

The seal member 34 has a substantially V-shaped cross section including a seal surface pressed against the outer peripheral surface of the ring portion 312 of the rotor 31 and the concave portion 304 of the partition wall 303 and a concave pressure-receiving surface behind the seal surface. The V-shaped top is directed toward the gap between the ring portion 312 and the partition wall 303, the pressure receiving surface is directed toward the pressurizing chamber 301a, and a lightly resilient state is formed in the concave portion 304 at the distal end of the partition wall of the housing 30. It is positioned and held and supported in its own shape (see FIG. 1).

The lid 32 is made of a press plate material,
In order to cover the end opening of the housing 30, the housing 30
A substantially square working chamber cover 323 conforming to the end surface shape and a parallelogram supply chamber cover 324 connected to the working chamber cover 323 are provided. An inwardly extending cylindrical support flange 325 protrudes from the center of the working chamber cover 323, and functions as a bearing that supports the inner diameter step of the ring 312 of the rotor 31.

In addition, the actuator 3 includes:
An elastomer seal 35 having an O-shaped cross section is provided. This is fitted into the seal groove 305 and the housing 3
It functions to seal between the 0 and the lid 32,
Circumferential part 3 that circulates the outer periphery of working chamber 301 and supply chamber 302
50, a branch 351 branching therefrom for sealing between the two chambers 301 and 302, and a branch 352 for sealing the partition 303.
And

A bearing bush 36 is provided to prevent the external teeth 211 of the ratchet wheel 21 from shaving the inner periphery of the support flange 306 of the housing 30 due to whirling of the winding shaft 2. This is inserted into the inner periphery of a support flange 306 protruding into the working chamber 301 of the housing 30 and has a flange 361 extending radially outward at one end.
Having. The flange 361 is located between the ring portion 312 of the rotor 31 and the end face of the support flange 306 in the assembled state, and performs the function of positioning the bush and the function of the thrust bearing.

In FIG. 3, reference numeral 41 denotes a primer of the gas generator 4 and 5 denotes an acceleration sensor.
The gas generator 4 is accommodated in a cylindrical gas generator accommodating portion 308 connected to the supply chamber 302 of the housing 30, and is pressed and fixed to the bottom of the accommodating portion 308 via the retaining ring 44 as the lid 32 is fixed. It faces the acceleration sensor 5 screwed to the outside of the bottom. Acceleration sensor 5
Is provided with a pin (not shown) for firing the primer 41, and the opening at the bottom of the housing portion into which the tip is introduced when the pin is pushed out is connected and sealed by the coupler 43.

Next, the operation of the above embodiment will be described based on FIG. 4, and the detailed configuration will be described with reference to FIG.
In this device, in the non-operating position, the rotor 31 is in a position shown in FIG. 4A in which the back of the clutch key 22 fitted to the rotor 31 abuts against the partition wall 303. In this state, the pressurizing chamber 301a is in the most contracted state, and the clutch key 22 is positioned by the key connector 23 and is in a position where it does not engage with the external teeth 211 of the ratchet wheel 21. Accordingly, the winding shaft 2 is completely separated from the actuator 3 and can freely rotate, and the function of the retractor is maintained as before. In this state, as shown in FIG.
1, the front end side is expanded toward the pressurizing chamber 301a, and the front end edge 331a is formed by self-elasticity.
It is in a state of being in elastic contact with the peripheral wall, the end wall, and the end wall of the lid 32.

Upon detecting the acceleration, the firing pin of the sensor 5 shown in FIG.
When the primer 41 is ignited and a gas pressure generated by combustion of a propellant such as nitrocellulose is applied to the key connector 23 in the supply chamber 302 (see FIG. 4B), the engagement by the hook 232 is released. Since the key connector 23 is pushed along the groove 300, the clutch key 22 is pushed by the key connector 23 and pushed inward, and the pawl 22
2 moves to a position where it contacts the peak of the external teeth 211 of the ratchet wheel 21. At this time, since the outer end of the key connector 23 reaches the outer peripheral surface of the pressurizing chamber 301a, the supply of gas to the pressurizing chamber 301a is started. At this point,
Since the gas pressure in the pressurizing chamber 301a has not yet been sufficiently increased, and the gas pressure applied to the lip 331 of the seal member 33 is low, gas escape from the pressurizing chamber 301a to the back pressure chamber 310b is mainly caused by the flexible lip. 331 is prevented by the elastic contact force of the self-elasticity. Preventing this initial outgassing is closely related to the subsequent gas pressure sealing function. At this stage, if gas escape occurs even from a part of the peripheral edge of the seal member 33, a phenomenon occurs in which the gas pressure that increases thereafter suddenly escapes from the pressurizing chamber 301a to the back pressure chamber 310b through this part, 33 lip 33
This is because the gas pressure sealing effect of No. 1 is no longer exhibited.

With the above operation, the gas pressure also acts on the vane 311 of the rotor 31 and pushes the back of the vane 311 via the flexible seal member 33, so that the rotor 31 rotates around the axis, and FIG. As shown in (1), a counterclockwise rotation is started. The back pressure chamber 3 of the working chamber 301 generated by this rotation
The pressure on the 01b side is released to the atmosphere via the exhaust hole 307 of the housing 30, and the generation of resistance due to the pressure increase on the back pressure chamber side is prevented. On the other hand, the displacement of the clutch key 22 is continued, and the pawl 222 of the clutch key 22 meshes with the external teeth 211 of the ratchet wheel 21 and the rotor 3
1 is a ratchet wheel 21 via a clutch key 22
Engage with. At this point, the winding shaft 2 is
Is linked to Then, the rotational force of the rotor 31 is transmitted to the winding shaft 2 via the clutch key 22 and the ratchet wheel 21 as shown in FIG. At these stages, the pressure in the pressurizing chamber 301a is high,
The prevention of gas leakage from the pressurizing chamber 301a to the back pressure chamber 301b is performed by the gas pressure acting behind the lip 331 of the flexible seal member 33 itself.

With the rotation operation of the winding shaft 2, the belt wound around the winding reel 1 is wound and the belt is tightened, and then the rotor 31 is shown in FIG. When the position is reached, the vane 311
3 and the rotation of the rotor 31 stops. At this position, the pressurizing chamber 301a is also opened to the atmosphere, so that the residual gas pressure is also exhausted. However, after this,
Since the take-up shaft 2 integrated with the take-up reel 1 tends to continue to rotate by its own inertia, as shown in FIG. Since the key 22 is pushed out in the disengagement direction and the winding shaft 2 is released from the rotor 31, the rotation of the winding shaft 2 continues.
The rotation by the inertia continues until the belt tension and the rotational moment of the inertia system including the take-up reel are balanced. The belt pull-in amount due to this rotation depends on the amount of propellant charged in the gas generator 4, but can be set to about 1/2 of the rotation rotation amount. As described above, the pretension is applied by the above series of operations. The belt withdrawal after this operation is completed is prevented by the engagement of the lock pawl 13, which is a component of the retractor R, with the ratchet internal teeth 101.

In the description of the series of operations,
In order to clarify the clutch engagement operation, the subsequent operation of the key connector is omitted, but the key connector 23 is not provided with the groove 3 during the clutch engagement process shown in FIGS. 4B to 4C.
When the rotor 31 starts rotating in a state where most of it has come off from 00, the leg portion is dragged by the clutch key 22, so that the engagement at the dovetail groove 231 is released and the clutch key 22 is released.

Although the present invention has been described in detail based on the embodiments, the shapes, arrangement positions, and materials of the respective components are not limited to those shown in the above embodiments, and fulfill desired functions. If so, various configurations can be adopted within the scope described in the claims.

[0027]

According to the present invention, the flexible lip of the seal member attached to the side of the pressurizing chamber of the vane has a periphery corresponding to the pressure of the gas supplied to the pressurizing chamber. Thus, it is possible to prevent gas leakage from the pressurizing chamber to the back pressure chamber, prevent a decrease in actuator driving force due to gas leakage, and secure a pretension stroke of the rotary actuator operating pretensioner. Then, diverging toward the tip side of the lip on the pressure chamber side, by the configuration that is elastic contact the leading edge to the cylinder by self-elasticity, because between the vanes of the peripheral and the cylinder from the beginning is sealed, in particular In addition, the function of preventing gas leakage from the pressurized chamber to the back pressure chamber at the time of gas pressure supply is improved. Furthermore, the configuration in which the seal member is provided with a hook projecting in the direction of the back pressure chamber, and the hook is engaged with the vane of the rotor, allows the hook to perform a positioning function when the seal member is assembled to the vane. A decrease in the sealing function due to the displacement can be avoided.

[Brief description of the drawings]

FIG. 1 is an end view showing a cylinder of a pretensioner according to an embodiment of the present invention with a lid removed.

FIG. 2 is an enlarged view showing the seal member of the embodiment in a partial cross section.

FIG. 3 is an exploded perspective view showing the entire components of the above embodiment together with a retractor.

FIG. 4 is an operation explanatory view showing the operation of the embodiment in order.

[Explanation of symbols]

 R retractor (belt tightening means) 3 actuator 4 gas generator 30 housing (cylinder) 31 rotor 32 lid (cylinder) 36 bush 301 working chamber 301a pressurizing chamber 301b back pressure chamber 303 partition wall 311 vane 33 seal member 331 lip 331a tip edge 332 hook

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60R 22/12-22/46

Claims (1)

(57) [Claims] 1. A gas generator, comprising: an actuator that winds a seat belt using gas supplied from the gas generator as a driving source; the actuator includes: a cylinder having an operating chamber communicating with the gas generator; A pressure chamber and a back pressure chamber, which are rotatably supported by the cylinder, are disposed in the working chamber, and cooperate with a partition formed in the cylinder to communicate the working chamber with a gas generator. And a rotor having a vane having a vane sectioned therewith. A seal member is attached to the pressurizing chamber side of the vane, and the seal member is supplied to the pressurizing chamber along a peripheral edge thereof. a flexible lip which is pressed against the cylinder by the pressure of that gas, comprising a hook that projects to the back pressure chamber direction, the lip Expanding the distal end side toward the pressurization chamber side
Open and self-elastic, the leading edge is elastically connected to the cylinder.
Wherein the hook is locked to a vane of the rotor .