JPH0747918A - Rotary actuator operation pretensioner - Google Patents

Abstract

PURPOSE:To prevent gas leakage from between a cylinder and a rotor and also prevent reduction of actuator driving force in a pretensioner having a rotary actuator as its driving means. CONSTITUTION:This rotary actuator operation pretensioner is composed of a gas generator 4 and actuator 3. The actuator 3 has an operation room 301 in its cylinder housing 30 and a rotor 31 having a vane 311, which partitions the operation room 301 into a pressurized room 301a communicating with the gas generator 4 and a back pressure room 301b open to the atmospheric air, is equipped inside the operation room 301. A seal member 33 is added to the pressurized room 301a side of the vane 311 and a flexible lip 331, which is brought in pressure contact with the cylinder 30 by the pressure of the gas supplied to the pressurized room 301a, is provided along the periphery of the seal member 33.

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 for a gas pressure actuated rotary actuator which constitutes a drive portion thereof.

[0002]

2. Description of the Related Art A pretensioner for a seat belt device of a vehicle or the like is provided for tightening a loosely mounted belt in an emergency such as a vehicle collision and for restraining an occupant's body to a seat to enhance the function of the seat belt. There are various types of operating mechanisms. Among them, in particular, as a typical example of the type in which the drive unit is a rotary actuator, the rotor with vanes is rotated by gas pressure in the cylinder, and thereby the seatbelt take-up reel is rotationally driven, conventionally, There is a technique disclosed in Japanese Patent Publication No. 59-15657. Further, as an example in which the vane is movable with respect to the rotor with the same thing, German Published Patent No. 2505626
There is a technique disclosed in the specification.

[0003]

By the way, unlike a direct-acting type actuator in which the stroke can be set by the cylinder length, in order to obtain the desired pre-tension stroke with less than one rotation of the rotor, the initial stage of operation is required. It is important to increase the rotor acceleration of the engine, and for that purpose, the high gas pressure immediately after the operation of the gas generator must be effectively captured by the vane pressure receiving surface. It is easy to come out from the gap. Therefore, in order to prevent this, the machining accuracy of the cylinder and the vane must be made extremely high to reduce the gap between them, or the gap must be sealed by a precise sealing means. However, such measures are unrealistic considering the manufacturing cost and size.

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

[0005]

In order to solve the above problems, the present invention comprises a gas generator and an actuator that winds a seat belt using a gas supplied from the gas generator as a drive source. Is a cylinder in which a working chamber communicating with the gas generator is formed, and is rotatably supported by the cylinder and is arranged in the working chamber. The partition wall formed in the cylinder cooperates with the working chamber. In a rotary actuator actuation pretensioner including a rotor having a vane that is divided into a pressure chamber that communicates with a gas generator and a back pressure chamber that is open to the atmosphere, a seal member is additionally provided on the pressure chamber side of the vane, The seal member is a flexible lip that is pressed against the cylinder by the pressure of the gas supplied to the pressurizing chamber along the periphery thereof. A structure that comprises.

The tip of the lip may be widened toward the pressurizing chamber side, and the tip edge may be elastically contacted with the cylinder by self-elasticity.

Further, the seal member may be provided with a hook projecting toward the back pressure chamber, and the hook may be engaged with a vane of the rotor.

[0008]

In the rotary actuator actuating pretensioner according to the present invention having such a structure, the flexible lip of the seal member attached to the pressurizing chamber side of the vane is
The periphery is pressed against the cylinder with a strength corresponding to the pressure of the gas supplied to the pressurizing chamber, and functions to prevent gas leakage from the pressurizing chamber to the back pressure chamber.

When the tip end side of the lip is widened toward the pressurizing chamber side and the tip end edge is elastically contacted with the cylinder by self-elasticity, the periphery of the vane and the cylinder are sealed from the beginning. Therefore, in particular, the function of preventing gas leakage from the pressurizing chamber to the back pressure chamber when gas pressure is initially supplied is improved.

Further, in the case where the seal member is provided with a hook protruding toward the back pressure chamber and the hook is locked to the vane of the rotor, the hook performs a positioning function when the seal member is assembled to the vane. It is possible to avoid the deterioration of the sealing function due to the displacement of the mounting position.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the rotary actuator actuation pretensioner includes a gas generator 4 and an actuator 3 that winds a seat belt using a gas supplied from the gas generator 4 as a drive source.
The actuator is arranged in the working chamber 301 while being rotatably supported by the housing 30 and a cylinder including a cylinder housing 30 having a working chamber 301 communicating with the gas generator 4 and a cylinder lid covering the opening surface thereof. The vane 311 that cooperates with the partition wall 303 formed in the housing 30 to divide the working chamber 301 into a pressurizing chamber 301a that communicates with the gas generator 4 and a back pressure chamber 301b that is open to the atmosphere through the exhaust hole 307 is provided. Rotor 31
With. A seal member 33 is attached to the pressurizing chamber 301a side of the vane 311. As shown in an enlarged manner in FIG. 2, the seal member 33 includes a flexible lip 331 that is pressed against the cylinder 30 by the pressure of the gas supplied to the pressurizing chamber 301a along the periphery thereof.

As shown in FIG. 3, the pretensioner in this example uses a retractor R as a seat belt retracting means. Therefore, one end of the actuator 3 is riveted and supported by the frame 10 of the retractor R. The retractor R is attached to the other end of the actuator 3.
The winding spring unit 12 is attached. Further, clutch means for engaging and disengaging the actuator 3 and the seat belt winding shaft 2 of the retractor R is provided. This clutch means is composed of a ratchet wheel 21 attached to the seat belt winding shaft 2 and a clutch key 22 attached to the rotor 31 side.

The ratchet wheel 21 is fitted into the taper portion of the take-up shaft 2 of the retractor R, and the inner end of the ratchet wheel 21 is formed in the take-up reel 1 to form an internal gear-like concave portion which is designated as the external tooth 211 of the ratchet wheel 21. It fits and is fixed to the shaft 2 against rotation. In the figure, reference numeral 13 indicates a lock pawl rotatably supported on the reel flange of the retractor R, and 101 indicates a frame 1 to which the lock pawl is engaged to prevent reverse rotation.
The 0 side ratchet internal tooth is shown.

Further, each part of the pretensioner will be described in detail with reference mainly to FIG. First, the housing 30 has a working chamber 301 whose one end face is open and which is surrounded by a cylindrical peripheral wall and an end wall. Similarly, one end face is open, which is surrounded by an arch-shaped enclosure wall and an end wall. Sandwiching the working chamber 30
1 and a supply chamber 302 adjacent thereto, and cooperates with a lid 32 that closes the end face opening thereof to make the working chamber 301 a substantially cylindrical space.

Working chamber 301 of housing 30 and supply chamber 3
No. 02 is communicated with a groove 300 formed in the housing wall at a portion where they oppose each other, and this groove 300 constitutes a through hole connecting both chambers. This groove 3 is provided in the housing 30.
A partition wall 303 is formed so as to be in contact with 00 and extend radially inward from the peripheral wall. A recess 304 is formed at the tip of the partition 303, and this serves as an accommodation support for the seal member 34, which will be described later. Further, a seal groove 305 is formed around the outer circumferences of the working chamber 301 and the supply chamber 302, and six screw holes 309 are formed outside the seal groove 305 at appropriate intervals in this example. It is set up. The screw hole 309 is referred to as the screw through hole 321 of the lid 32,
It is for screwing a fastening screw 39 for fixing the lid 32 to the housing 30. Further, an annular support flange 30 protruding from the end wall so as to surround the shaft hole of the working chamber 301.
6 and an exhaust hole 307 that opens the working chamber 301 to the outside of the housing 30.

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

The seal member 33 according to the present subject matter is made of a flexible plastic material such as nylon. The seal member 33 includes an attachment portion 330 having a shape substantially matching the shape of the pressure receiving surface of the vane 311 and the rotor ring portion 3 thereof.
It has mutually continuous seal lips 331 which stand upright from three peripheral edges except the edge portion which contacts 12. Of these lips 331, those that come into contact with the peripheral wall of the working chamber 301 are not shown in the figure because they are located on the back side of the attachment portion 330. As shown enlarged in FIG. 2, each seal lip 33
In No. 1, the front end side of the No. 1 widens toward the pressurizing chamber 301a side by a predetermined angle α. This is a structure for assembling the seal member 33 to the vane 311 so that the seal lip 331 elastically contacts the tip edge 331a with the cylinder, that is, the housing 30 and the lid 32 by its self-elasticity. These seal lips 331 are
During the rotation, the gas pressure presses the both end surfaces (one end surface is the inner end surface of the lid 32) of the working chamber 301 and the peripheral surface to seal the gap between the housing 30 and the vanes 311.

Further, the seal member 33 is formed with a hook 332 projecting in the direction opposite to the direction of the back pressure chamber, that is, the rising direction of the lip 331. The hook 332 constitutes locking means that is locked to the notches 314 formed at both corners of the tip of the vane 311 of the rotor 33, and is hooked when the seal member 33 is assembled to the vane 311. 332 serves as a positioning and has a function of avoiding the deterioration of the sealing function due to the displacement of the mounting position.

The clutch key 22 is provided with a pressure receiving head 221 that receives gas pressure and a wedge-shaped pawl 222 that constitutes an engaging means for engaging the ratchet wheel 21, and the pawl 222 is arranged toward the ratchet wheel 21 side. It The key connector 23 is locked to the pressure receiving head 221 of the clutch key 22. This is the clutch key 22
Is provided to fulfill the function of placing the engine at a predetermined position when it is not operated and the function of controlling the supply of the gas pressure from the supply chamber 302 to the operation chamber 301. Therefore, it is associated with the pressure receiving head 221 of the clutch key 22. With a matching ant groove 231
An engaging hook 232 for engaging the opening of the groove 300 is provided.

The seal member 34 has a substantially V-shaped cross section having a seal surface which is 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 them. The V-shaped top portion faces the gap between the ring portion 312 and the partition wall 303, and the pressure receiving surface faces the pressurizing chamber 301a.
Positioned in its own shape, with a lightly elastic state on 04,
It is accommodated and supported (see FIG. 1).

The lid 32 is made of a press plate material, and in order to cover the end face opening of the housing 30, a substantially square working chamber cover part 323 conforming to the end face shape of the housing 30 and a parallelogrammatic supply chamber cover part 324 connected to it. It has and. A cylindrical support flange 325 that extends inward is provided at the center of the working chamber cover 323, and this functions as a bearing that supports the inner diameter side step of the ring portion 312 of the rotor 31.

In addition to this, the actuator 3 has an O
An elastomer seal 35 having a V-shaped cross section is provided. This is fitted in the seal groove 305 to form the housing 3
It serves to seal between 0 and the lid 32,
Circulating section 3 that circulates around the outer periphery of the working chamber 301 and the supply chamber 302.
50, a branch portion 351 branching from the branch portion 351 to seal between the chambers 301 and 302, and a branch portion 352 sealing the partition wall 303 portion.
Have and.

A bearing bush 36 is provided in order to prevent the outer teeth 211 of the ratchet wheel 21 from scraping the inner circumference of the support flange 306 of the housing 30 due to the whirling of the winding shaft 2. This is inserted into the inner circumference of the support flange 306 protruding into the working chamber 301 of the housing 30, and has a flange 361 extending outward in the radial direction at one end side. In the assembled state, this flange 361 is located between the ring portion 312 of the rotor 31 and the end surface of the support flange 306, and functions as a bush and as a thrust bearing.

In FIG. 3, reference numeral 41 is a primer of the gas generator 4, and 5 is an acceleration sensor. The gas generator 4 is accommodated in a tubular gas generator accommodating portion 308 that is connected to the supply chamber 302 of the housing 30, and is pressed and fixed to the bottom portion of the accommodating portion 308 via the retaining ring 44 when the lid 32 is fixed, It faces the acceleration sensor 5 which is screwed to the outside of the bottom. The acceleration sensor 5 is provided with a pin (not shown) that strikes the primer 41, and the opening at the bottom of the accommodating portion, into which the tip of the pin 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 with reference to FIG. 4 and the detailed configuration with reference to FIG. In this device, in the non-actuated position, the rotor 31 is in the position shown in FIG. 4A in which the back of the clutch key 22 fitted therein is brought into contact with the partition wall 303. In this state,
The pressurizing chamber 301a is in the most contracted state, the clutch key 22 is positioned by the key connector 23,
It is in a position where it does not engage with the outer teeth 211 of the ratchet wheel 21. Therefore, the winding shaft 2 is completely separated from the actuator 3 and is freely rotatable, and the function of the retractor is maintained as usual. In this state, as shown in FIG. 2, the flexible lip 331 of the seal member 33 is formed.
However, the front end side is expanded toward the pressurizing chamber 301a side, and the front end edge 331a is moved to the cylinder housing 30 by self elasticity.
It is in a state of being elastically contacted with the peripheral wall, the end wall, and the end wall of the lid 32.

When the acceleration is detected, the firing pin of the sensor 5 shown in FIG. 3 fires, the primer 41 of the gas generator 4 ignites, and the generated gas pressure due to the combustion of the propellant such as nitrocellulose is supplied in the supply chamber 302. When applied to the key connector 23 (see FIG. 4B), the engagement by the hook 232 is released, and the key connector 23 is released into the groove 3.
00, the clutch key 22 is pushed inward by the key connector 23, and the pawl 222
Moves to a position where it contacts the peaks of the outer teeth 211 of the ratchet wheel 21. At this time, since the outer end portion 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, the gas pressure in the pressurizing chamber 301a has not yet risen sufficiently and the gas pressure applied to the lip 331 of the seal member 33 is also low,
Gas escape from the pressurizing chamber 301a to the back pressure chamber 310b is prevented mainly by the elastic contact force of the flexible lip 331 due to self-elasticity. Preventing this initial outgassing is closely related to the subsequent gas pressure sealing function. This is because, if gas escape occurs even from a part of the peripheral edge of the seal member 33 at this stage, the gas pressure that rises thereafter suddenly escapes from the pressurizing chamber 301a to the back pressure chamber 310b through the part, and the seal member This is because the gas pressure sealing effect by the lip 331 of 33 is not exerted.

By the above operation, the gas pressure also acts on the vanes 311 of the rotor 31 and pushes the back of the vanes 311 via the flexible seal member 33, so that the rotor 31 rotates around its axis, as shown in FIG. As shown in, the 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 into the atmosphere through 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 eventually the pawl 222 of the clutch key 22 meshes with the outer 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 take-up shaft 2 has the actuator 3
Connected with. 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 on the pressurizing chamber 301a side becomes high pressure,
The gas pressure itself acting behind the lip 331 of the flexible sealing member 33 prevents the gas from leaking from the pressurizing chamber 301a to the back pressure chamber 301b.

As the winding shaft 2 rotates,
The belt wound around the take-up reel 1 is wound, the belt is tightened, and eventually the rotor 31 reaches the position shown in FIG.
3 and the rotor 31 stops rotating. At this position, the pressurizing chamber 301a is also open to the atmosphere, so that the residual gas pressure is also exhausted. However, even after this,
Since the take-up shaft 2 integrated with the take-up reel 1 tries to continue to rotate due to its own inertia, this time, 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.
Then, the rotation due to this inertia continues until the belt tension and the rotation moment of the inertial system including the take-up reel are balanced. The amount of belt retracted by this rotation can be about 1/2 of the amount of rotor rotation, although it depends on the amount of propellant loaded in the gas generator 4. In this way, the pretension is applied by the series of operations described above. The belt withdrawal after the completion of this operation is blocked by the engagement of the lock pawl 13, which is a constituent element of the retractor R, with the ratchet internal teeth 101.

In the description of the series of operations, the subsequent operation of the key connector is omitted in order to clarify the clutch engagement operation, but the key connector 23 is shown in FIGS. 4 (B) to 4 (C). Groove 3 during the clutch engagement process
When the rotor 31 starts to rotate in a state in which most of it has been pulled out from 00, the legs are dragged by the clutch key 22, so that the engagement in the dovetail groove 231 is released and the clutch key 22 is disengaged.

The present invention has been described above in detail based on the embodiments.
The shape, arrangement position, and material of each component are not limited to those shown in the above-mentioned embodiment, and various components within the scope of the claims may be used as long as they fulfill the intended functions. The configuration can be adopted.

[0031]

According to the present invention, the flexible lip of the sealing member provided on the pressurizing chamber side of the vane has the strength corresponding to the pressure of the gas supplied to the pressurizing chamber at the peripheral edge thereof. It is possible to prevent the gas from leaking from the pressurizing chamber to the back pressure chamber by preventing the actuator driving force from decreasing due to the gas leak, and to secure the pre-tension stroke of the rotary actuator actuating pretensioner.

When the tip end side of the lip is expanded toward the pressurizing chamber side and the tip end edge is elastically contacted with the cylinder by self-elasticity, the vane peripheral edge and the cylinder are sealed from the beginning. In particular, the function of preventing gas leakage from the pressurizing chamber at the beginning of gas pressure supply to the back pressure chamber is improved.

Further, in the case where the seal member is provided with a hook projecting toward the back pressure chamber and the hook is locked to the vane of the rotor, the hook fulfills a positioning function when the seal member is assembled to the vane. It is possible to avoid the deterioration of the sealing function due to the displacement of the mounting position.

[Brief description of 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 a partial cross section of the seal member of the above embodiment.

FIG. 3 is a perspective view showing the entire constituent elements of the above embodiment in a disassembled state together with a retractor.

FIG. 4 is an operation explanatory view showing the operation of the above 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

Claims (3)

[Claims] 1. A gas generator and an actuator that winds a seat belt using a gas supplied from the gas generator as a drive source, and the actuator includes a cylinder having a working chamber communicating with the gas generator. A pressure chamber that is rotatably supported by the cylinder, is disposed in the working chamber, and cooperates with a partition formed in the cylinder to communicate the working chamber with a gas generator, and a back pressure chamber that is open to the atmosphere. In a rotary actuator actuation pretensioner including a rotor having a vane sectioned into, 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. Rotary actuator operation characterized in that it comprises a flexible lip pressed against the cylinder by the pressure of the gas Ritenshona. 2. The pre-tensioner for operating a rotary actuator according to claim 1, wherein a tip end of the lip widens toward the pressurizing chamber side, and a tip end of the lip is elastically contacted with the cylinder by self-elasticity. 3. The pre-tensioner for operating a rotary actuator according to claim 1, wherein the seal member includes a hook that projects toward the back pressure chamber, and the hook is locked to a vane of the rotor.