JP3174836B2 - 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 pretensioner for rotating a seat belt winding shaft by a gas-operated rotary actuator.

[0002]

2. Description of the Related Art A pretensioner in a seat belt device is provided to enhance a function of restraining a passenger's body to a seat by tightening a loosely mounted belt in an emergency such as a vehicle collision or the like. Among them, among them, in particular, a gas pressure operated rotary actuator is arranged in connection with the seat belt winding mechanism,
Japanese Patent Application Laid-Open No. 58-195571 (Prior Art 1) discloses a device provided with a mechanism for rotating a seat belt winding shaft or a winding reel by a rotating element of an actuator.
There are techniques disclosed in Japanese Patent Publication No. 59-15657 (prior art 2) and Japanese Patent Application Laid-Open No. 60-45449 (prior art 3).

When the retractor seat belt retracting mechanism is used as it is for the pretensioner retracting mechanism, the pretensioner must not interfere with the retractor's normal belt retracting and feeding operation. The rotating element of the actuator is placed in a state of being separated from the seat belt winding shaft or the winding reel, and is engaged with them only during operation.

[0004]

With respect to such a clutch mechanism for disengagement, the above prior arts will be described.
In the configurations of the prior arts 1 and 3, not only the clutch mechanism becomes complicated and cost increases, but also the clutch mechanism must be arranged in series with the rotating element in the axial direction of the winding shaft. The dimensions become longer. On the other hand, the configuration of the prior art 2 is rational in that it has a simple configuration in which the pins supported by the blades are operated by using gas pressure. Since it is an axial hole formed in the flange of the take-up reel, the arrangement pitch of the holes is naturally limited in relation to the hole diameter, and cannot be extremely fine. In addition, since the engagement of the pin with the hole is normally enabled after the rotation of the blade, the stability of the engagement operation is not necessarily satisfactory.

The present invention has been devised in view of the above-mentioned circumstances, and in a pretensioner for rotating a seat belt winding shaft by a rotary actuator, it is possible to devise an actuator and a clutch mechanism, and the invention is made possible thereby. A rotary actuator that realizes a more reliable and smoother engagement between the rotating element of the actuator and the seat belt winding shaft while suppressing an increase in the length of the seat belt winding shaft by improving the arrangement position. It is an object to provide a working pretensioner.

[0006]

In order to solve the above-mentioned problems, a rotary actuator operating pretensioner according to the present invention is provided with a rotary pre-tensioner mounted on a pretensioner base for supporting a seat belt winding shaft. An actuator, a gas generator for supplying a working gas to a pressure chamber of the actuator, and clutch means for connecting a rotating element of the actuator to the shaft with a working gas pressure supplied to the pressure chamber from the gas generator; The actuator is formed in an annular shape defining a space in an inner diameter portion thereof, the clutch means is disposed in the space, the clutch means includes a ratchet wheel attached to the shaft, A clutch key movably supported by a rotating element and a working gas pressure applied to the clutch key; The supply of the working gas to reach said pressure chamber is obtained is composed of a key connector for sequencing.

[0007]

According to the present invention having such a configuration, when the gas generator operates by a signal from an electric or mechanical sensor responding to acceleration and the working gas is supplied to the pressure chamber of the actuator, the clutch key is operated. The transmission of the working gas pressure to the pressure chamber and the supply of the working gas to the pressure chamber are controlled in sequence by the operation of the key connector. Therefore, initially, the gas pressure transmission from the key connector pushes the clutch key toward the ratchet wheel located in the space defined by the inner diameter of the actuator, and engages or contacts the ratchet wheel. Thereafter, supply of the working gas to the pressure chamber by the key connector is started, and the rotating element starts rotating. At this time, when the clutch key is already in the engaged state with the ratchet wheel, when the clutch key is in the contact state, the engagement of the two is achieved with the rotation of the rotating element, and the rotational force of the rotating element is achieved. Is transmitted to the seat belt winding shaft. As a result of such a rotation operation, a pretension applying operation is performed by winding the seat belt.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. As shown in FIG. 1, this pretensioner is disposed on a pretensioner base (in this example, which also serves as a retractor frame as shown in FIG. 3) 2 which supports the seat belt winding shaft 1 so as to rotate the shaft. A rotary actuator 3 provided, a gas generator 4 for supplying a working gas to a pressure chamber C of the actuator 3, and a clutch for connecting a rotor 31 which is a rotating element of the actuator 3 to the shaft 1 by gas pressure supplied to the pressure chamber C Means 5. The actuator 3 has a space S in its inner diameter.
And a clutch means 5 is provided in the space S. The clutch means 5 includes a ratchet wheel 51 attached to the shaft 1, a clutch key 52 movably supported by the rotor 31 toward the ratchet wheel 51, transmission of working gas pressure to the clutch key 52, and operation to the pressure chamber C. And a key connector 53 for controlling the supply of gas in order. In this example, the arrangement is not limited to this, but for the reason described later, the clutch key 52 directs its movement axis X in a direction intersecting the center axis Y of the ratchet wheel 51 at a predetermined interval D (hereinafter, referred to as the following). , This state is referred to as offset), and the head 521 is arranged so as to face the pressure chamber C side.

Further, each part of this embodiment will be described in detail with reference mainly to FIG. First, the seat belt winding shaft 1 is integrated with a reel 11 that winds a belt webbing (not shown). As is well known, the reel 11 has a slit 12 for inserting the end of the belt webbing, and flanges 13 and 14 at both ends. An annular flange 141 is formed on one of the flanges 14 so as to slightly protrude in the axial direction surrounding the periphery of the winding shaft 1, and a ratchet wheel formed separately from the winding shaft 1 in this example on an inner peripheral surface thereof. Inner teeth 142 meshing with the outer teeth 511 are formed so that the inner end of 51 can be inserted,
It constitutes a detent when the ratchet wheel 51 is fitted on the winding shaft 1.

The pretensioner base 2 is formed in a channel shape to support both ends of the take-up shaft 1. In this example,
As mentioned above, since it also serves as a retractor frame,
Side walls 2 on which both reel flanges 13 and 14 are fitted
Ratchet internal teeth 25 and 26 with which lock pawls described later are engaged are formed on the inner circumferences of the openings 23 and 24 of the first and second openings 23, 24. Although detailed description of the components of the retractor is omitted, in the drawings, reference numeral 18 denotes an emergency lock mechanism,
Reference numerals 5 and 16 denote lock pawls operated thereby, reference numeral 17 denotes a connecting shaft supported by a reel and connects the lock pawls 15 and 16 to each other, reference numeral 20 denotes a take-up spring unit,
Reference numeral 27 denotes a belt passing guide that is fitted into the base 2 and guides the belt webbing.

Next, each part of the actuator 3 will be described in detail. In this example, the actuator 3 includes a cylinder 30 forming a fixed element, a rotor 31 forming a rotating element, and a lid 3 closing an open end of the cylinder 30.
And 2. The cylinder 30 has an annular working space Q (see FIG. 1) whose one end face is open, is surrounded by an inner peripheral wall 301, an outer peripheral wall 302, and an end wall 303, and is partially blocked in a radial direction by a partition wall 304. The supply chamber R (see FIG. 1) that is in contact with the space Q is configured by blocks formed therein. In the vicinity of one side of the partition wall 304, a gas supply and key connector fitting groove 30 for communicating the supply chamber R with the working space Q is provided.
0 is formed, and an exhaust hole 305 that penetrates the outer peripheral wall 302 and opens the working space Q to the atmosphere is formed near the other side. Further, a seal groove 306 is formed on the open end face of the cylinder 30 so as to surround the outer periphery of the working space Q and the outer periphery of the supply chamber R. On the other hand, from the inner end face of the lid 32, the cylinder 3
An annular axial flange 321 that protrudes from the inner peripheral wall 301 of the rotor 31 with a predetermined gap therebetween and forms a bearing that supports the inner diameter side of the rotor 31 in cooperation therewith.

The rotor 31 constitutes an inner peripheral wall of the working space Q, and has a ring portion 311 defining a space S (see FIG. 1) on the inner diameter side thereof, and a vane functioning as a pressure receiving portion extending radially from the ring portion 311. 312 are provided. Vane 3
A square hole 313 that penetrates the ring portion 311 to be fitted with the clutch key 52 is formed at the back of the rotating direction 12 as described above. The inner diameter side of the ring portion 311 is a stepped hole whose both ends are enlarged so that the inner peripheral wall 301 of the cylinder 30 and the axial flange 321 of the lid 32 can be inserted.

On the pressure receiving surface side of the vane 312, a seal member 314 having a seal lip continuous to both end edges and an outer peripheral edge is provided. The sealing material 314 is attached to the rear surface of the vane 312 by hooking a notch formed at both corners of the tip of the vane 312 and attached to the rear surface of the vane 312. Performs the function of preventing gas leakage to

A clutch key 52 constituting an engaging means on the actuator side of the clutch means is inserted into the square hole 313 so as to be displaceable in the offset direction. Clutch key 52
The head includes a head 521 that forms a pressure receiving part that receives a gas pressure and a pawl 522 that forms engagement means for engaging the external teeth 511 of the ratchet wheel 51. The pawl 522 includes a ratchet. It is arranged toward the wheel 51 side. A key connector 53 is connected to the head of the clutch key 52. The key connector 53 constitutes locking means for holding the clutch key 52 at the initial position.

Here, the details of the clutch key 52 and the key connector 53 will be described. As shown in FIG. 2, the clutch key 52 is made of steel, and includes a rectangular head 521, a prismatic guide 520, and a pawl 522 at the tip thereof. A protruding overhang 523 is formed. On the other hand, the key connector 53 is made of plastic and has legs (clutch key 52).
531) and the guide portion 530 are formed in an L-shape. A dovetail groove 532 is formed on the leg portion 531 to engage with the overhang 523 of the clutch key 52. The guide portion 530 is fitted at the tip of the guide portion 530 which is fitted into the gas supply and key connector fitting groove 300 of the cylinder 30 without any gap. , Control groove 53
A hook claw 535 is formed at one end of a wall which defines the groove and is elastically displaceable in the groove direction by a thin-walled structure.

The clutch key 52 and the key connector 53 having the above-described construction are arranged such that the protrusion 523 of the former is replaced with the dovetail groove 5 of the latter.
32 to be connected to each other. In this combined state, as can be seen with reference to FIG. 1, in the former, the guide 520 is fitted in the square hole 313 of the rotor 31, and in the latter, the guide 530 is fitted in the groove 300 of the cylinder 30. Built into the state. At this time, the hook claw 535 engages with a corner where the peripheral wall of the supply chamber R intersects the groove 300, and the leg 53
The side of the anti-dove groove 1 is in contact with the peripheral wall of the cylinder 30. In this position, the guide portion 530 of the key connector 53 substantially closes the groove 300 over substantially the entire length thereof, and shuts off the supply chamber R and the pressure chamber C. At this time, the control groove 534 is set so that the sealing distance from the inner end of the cylinder peripheral wall to the bottom of the control groove 534 is equal to the stroke of the clutch key 52 until the tooth tip collision with the ratchet wheel 51 occurs.

Returning to FIG. 3, a radially deep groove is formed in the partition wall 304, and the sealing member 3 accommodated therein is formed.
Reference numeral 07 is a sliding contact seal which is pressed by a spring 308 embedded in the back thereof and presses the tip against the outer peripheral surface of the ring portion 311 of the rotor 31. This sealing member 30
7, an engagement groove 310 is formed in the seal surface of the tip end of the rotor 31 in parallel with the axis of the rotor 31 as shown in FIG.
A ridge 315 is formed on the outer periphery of the ring portion 311 of the rotor 31 facing the rotor. These form a click stop that engages with each other and holds the rotor 31 in the initial position.

In addition, the actuator 1 has O
A ring-shaped elastomer seal 33 is provided. This is fitted in the seal groove 306, orbits around the supply chamber R and the working space Q, and protrudes between them and into the partition wall portion to provide a sealing function between the cylinder 30 and the lid 32. Fulfill.

Next, the gas generator 4 is of a type in which the propellant charged in the case is burned by the firing of the primer 41. In this example, the propellant is incorporated in the cylinder 30. Therefore, the cylinder 30 has a bottomed cylindrical storage chamber 340 connected to the supply chamber R in parallel with the winding shaft 1 so as to store the gas generator 4. At the bottom of the storage chamber 340, there is formed an introduction hole for a firing pin (projected when the acceleration sensor 9 is activated) of the acceleration sensor 9 for starting the gas generator 4 attached thereto. A sealing sleeve 42 with a flange is fitted into the introduction hole from the accommodation room 340 side, and the accommodation room 3
The gas generator 4 to which the primer 41 is attached is inserted into 40, and the gas generator 4 is supported by being fitted with a snap ring 43.

Finally, as described above, the clutch means 5 is a ratchet wheel 51 which is a winding shaft side engaging means.
And a clutch key 52 as an actuator-side engaging means.
The ratchet wheel 51 has a helical tooth shape whose external teeth 511 are inclined backward with respect to the ratchet rotation direction. Correspondingly, the pawl 522 of the clutch key 52 also has a helical shape. This is to prevent the pawl 522 from coming off during the engaging operation of the pawl 522 with respect to the external teeth 511.

The above elements are not limited to these, but are arranged on the base 2 in the following procedure, for example. That is, first, an assembly in which the lock mechanism 18 is attached to one end of the reel 11 is inserted into both side openings 23 and 24 of the base 2. Then, the lock mechanism 18 is connected to the winding shaft support hole 1.
The cover 19 provided with the cover 91 is centered and attached by fitting the respective projections 190 into the attachment holes 210 of the base 2 so as to cover the lock mechanism 18. Next, the ratchet wheel 51 is attached to the large diameter portion 101 of the winding shaft 1 having one end supported in this manner.
Fit. At this time, the ratchet wheel 51 engages with the take-up shaft 1 so that the external teeth 511 are engaged with the internal teeth 142 and are dropped, so that the ratchet wheel 51 cannot rotate relatively. Next, the cylinder 30 is bolted to the other side wall 22. further,
From the open end face side of the cylinder 30, the rotor 31 incorporating the clutch key 52 and the sealing material 314 connected to the key connector 53 and the sealing ring 33 are fitted. Secure with screws. Finally, the spring unit 20 is fixed by engaging the projection 201 provided on the spring unit 20 with a mounting hole extending from the lid 33 to the cylinder 30 to complete the assembly. Thus, the winding shaft 1 has one end supported on one side of the base 2 via the cover 19 and the other end connected to the spring unit 20.
And is supported by the other side of the base 2 via

Next, the operation of the above embodiment will be described. FIG. 4 shows the operation of the pretensioner configured as described above. In this device, in the non-operation position,
The rotor 31 is at a position shown in FIG. 2A where the back of the clutch key 52 fitted to the rotor 31 abuts against the partition wall 304. In this state, the pressure chamber C is in the most contracted state, the clutch key 52 is positioned by the key connector 53 (see FIG. 1), and is at a position where it does not engage with the external teeth 511 of the ratchet wheel 51. Accordingly, the winding shaft 1 is completely separated from the actuator 3 and can freely rotate, and the function of the retractor is maintained as before.

When the acceleration pin is detected, the firing pin of the sensor 9 (see FIG. 3) fires, and the gas generator 4
When the primer 41 is fired (see (B) in the figure) and the gas generated by the combustion of the propellant is applied to the key connector 53 in the supply chamber R, the engagement by the hook 535 (see FIG. 2) is released. As the key connector 53 is pushed along the groove 300, the clutch key 52 is pushed by the key connector 53 and pushed inward in the offset direction, and the pawl 522 is pressed.
Moves to a position where it contacts the peak of the external teeth 511 of the ratchet wheel 51. At this time, since the bottom of the control groove 534 of the key connector 53 reaches the outer peripheral surface of the pressure chamber C, the supply of the working gas to the pressure chamber C is started.

As a result, the gas pressure also acts on the vane 312 of the rotor 31 and pushes behind the vane 312, so that the rotor 31 starts to rotate counterclockwise around the axis as shown in FIG. I do. The pressure on the back pressure chamber side of the working space Q generated by this rotation is released into the atmosphere via the exhaust hole 305 of the cylinder 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 52 is continued, and when the pawl 522 of the clutch key 52 eventually meshes with the external teeth 511 of the ratchet wheel 51, the rotor 31 engages with the ratchet wheel 51 via the clutch key 52. At this point, the winding shaft 1 is connected to the actuator 3. Then, the rotational force of the rotor 31 is transmitted to the winding shaft 1 via the clutch key 52 and the ratchet wheel 51 as shown in FIG.

As the winding shaft 1 rotates,
The belt wound around the winding shaft 1 is wound, and pretension is applied by tightening the belt. And
Eventually, the rotor 31 reaches the position shown in FIG. At this position, the pressure chamber C is also opened to the atmosphere, so that the residual gas pressure is also exhausted. After this, since the winding shaft 1 integrated with the reel 11 continues to rotate by its own inertia, the external teeth 511 of the ratchet wheel 51 move the clutch key 52 in the disengagement direction. The rotation of the winding shaft 1 is continued even after the vane 312 of the rotor 31 collides with the partition wall and stops rotating. The amount of belt withdrawal due to this rotation depends on the amount of propellant charged into the gas generator 4, but is about 1/2 of the amount due to rotation of the rotor.
Degree. Thus, the pretension providing operation is completed. The belt withdrawal after the completion of this operation is prevented by the engagement of the lock pawls 15 and 16, which are components of the retractor, with the ratchet internal teeth 25 and 26.

Here, the engagement operation of the clutch means 5 will be described in more detail. FIG. 5 shows the progress of engagement when the tip of the external teeth 511 of the ratchet wheel 51 and the tip of the pawl 522 of the clutch key 52 initially collide with the worst condition among various assumed engagement conditions. Are shown in order.
First, the key connector 53 is pressed by gas pressure from the initial state shown in FIG. The pawl 522 of the clutch key 52 with the progress of the pushing.
Of the ratchet wheel 51 to the position where the tooth tip collides with the tooth tip of the external tooth 511 of the ratchet wheel 51, the external tooth G shown in FIG.
The tooth tip collision with zero occurs. At this time, the key connector 5
The bottom of the third control groove 534 reaches the outer periphery of the pressure chamber C. Then, gas supply to the pressure chamber C is started from this position,
Rotation of the rotor 31 starts. The distance in the offset direction between the tooth tip and the inner circumference of the ring portion at this time is defined as h0. In this state, the ratchet wheel 51 is still stopped, and the rotor 31 starts accelerating at a certain angular acceleration.
Is zero in the offset direction.

Next, the clutch key 52 which could not be engaged in this state is rotated by a certain angle from this position,
As shown in FIG. 7C, the rotation angle becomes a1, and the next external tooth G
The speed is re-accelerated from 0 before reaching 1. The sum h1 of the moving distance in the offset direction obtained by the re-acceleration and the moving distance up to the initial tooth tip collision is the distance h.
Be sure to be larger than 0. In particular, the rotor 31 is made of the same material.
And the clutch key 52, the inertial mass of the clutch key 52 is much smaller than the inertial mass of the rotor 31, so that the rotor 31 is accelerated from the external teeth G0 to the position of G1 while rotating to the angle a2. By the re-acceleration, a sufficient meshing margin r is obtained as shown (D) by the time the tip of the pawl 522 finally collides with the next external tooth G1. Therefore, the clutch key 52 is engaged with the next external tooth G1 at worst, regardless of the positional relationship between the external teeth 511 of the ratchet wheel 51 and the tooth tip. The rotor rotation angle a2 up to the engagement is such that the inertia mass of the rotor 31 and the inertia mass of the clutch key 52 are made of the same material, and the clutch key 52 is made of steel and the rotor 31 is made of a light alloy. It is still about 36.5 degrees even when approaching more than the case described above.

In the description of the series of operations, the operation of the key connector is omitted in order to clarify the clutch engagement operation. However, the key connector 53 is provided with the clutch engagement shown in FIGS. When the rotor 31 starts to rotate and the leg is dragged by the clutch key 52 in a state where most of the groove has escaped from the groove 300 during the process, the engagement in the dovetail groove is released and the clutch key 52 is released.

Also, when the clutch key 52 collides with the external teeth 511 of the ratchet wheel 51 during the clutch engagement operation in this embodiment, as shown in FIG. Since the position is located at a distance D from the axis Y, most of the impact force is a rotational moment about the axis Y, and the component in the axis Y direction is extremely small. As a result, the winding shaft 1 is
Can be greatly reduced.

As described above, the present invention has been described in detail as a type to be combined with a retractor based on the embodiments. However, the present invention has a configuration suitable for it, but is not necessarily limited thereto. Further, the shape, arrangement position, and material of each component are not limited to those shown in the above-described embodiment, but may be any one that fulfills the intended function within the scope described in the claims. Various configurations can be adopted.

[0031]

According to the present invention, the sequence control of the key connector guarantees the rotation start of the rotor after the clutch engagement condition is adjusted. Therefore, when a ratchet collision between the ratchet wheel and the clutch key occurs. However, the engagement with the adjacent teeth easily occurs due to the shift of the tooth tip, and therefore, a stable clutch engagement operation is always ensured.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing details of a clutch key and a key connector of the embodiment.

FIG. 3 is an exploded perspective view showing the details of the components of the above embodiment in an exploded manner.

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

FIG. 5 is an operation explanatory diagram showing the clutch engagement operation of the embodiment in order.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 seat belt winding shaft 2 pretensioner base 3 rotary actuator 4 gas generator 5 clutch means 31 rotating element (rotor) 51 ratchet wheel 52 clutch key 53 key connector C pressure chamber S space

Continuation of front page (56) References JP-A-58-195571 (JP, A) JP-A-60-45449 (JP, A) JP-A-60-45450 (JP, A) JP-A-58-195574 (JP) JP-A-58-195570 (JP, A) JP-A-54-142730 (JP, A) JP-A-58-195573 (JP, A) JP-A-51-112023 (JP, A) 60-45449 (JP, A) Japanese Patent Publication No. 59-15657 (JP, B2) West German Patent Application Publication 2535380 (DE, A1) West German Patent Application Publication 3215928 (DE, A1) West German Patent Application Publication 3531856 (DE, A1) A1) West German Patent Application Publication 2620067 (DE, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 22/12-22/48

Claims (1)

(57) [Claims] 1. A rotary actuator disposed on a pretensioner base supporting a seat belt winding shaft for rotating the seat belt winding shaft, a gas generator for supplying a working gas to a pressure chamber of the actuator, and a gas generator. Clutch means for connecting a rotating element of the actuator to the shaft with a working gas pressure supplied to the pressure chamber, wherein the actuator is formed in an annular shape defining a space at an inner diameter thereof, and the clutch is provided in the space. Means are disposed, the clutch means includes a ratchet wheel attached to the shaft, a clutch key movably supported by the rotating element toward the ratchet wheel, and transmission of operating gas pressure to the clutch key. A key connector for sequentially controlling the supply of the working gas to the pressure chamber. Actuator pretensioner.