JP3174835B2 - 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, and the clutch means is movably supported by a ratchet wheel attached to the shaft and the rotating element. The clutch key has a movement axis line which is formed by the ratchet. It is directed in a direction intersecting at a center axis by a predetermined distance of the wheel, a configuration that it is positioned facing the pressure receiving portion to the pressure chamber.

[0007]

According to the present invention having such a configuration, when the gas generator operates in response to a signal from an electric or mechanical sensor responding to the acceleration and the working gas is supplied to the pressure chamber of the actuator, the gas pressure is reduced. Acts not only on the rotating element but also on the pressure receiving portion of the clutch key supported thereon, and pushes and engages the clutch key toward the ratchet wheel located in the space defined by the inner diameter of the actuator. During this engagement operation, most of the impact force due to the collision of the clutch key with the ratchet wheel is converted into rotational force with respect to the ratchet wheel due to the distance between the axis of movement of the clutch key and the center axis of the ratchet wheel. The impact bending load applied to the winding shaft is greatly reduced. Thus, the rotating element is connected to the winding shaft, and the rotational force of the rotating element 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. 2) 2 for supporting the seat belt winding shaft 1 for rotating 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 comprises a ratchet wheel 51 attached to the shaft 1 and a clutch key 52 movably supported by the rotor 31.
Is arranged so that the movement axis X is directed in a direction intersecting the center axis Y of the ratchet wheel 51 at a predetermined interval D (hereinafter, this state is referred to as offset), and the pressure receiving portion 521 faces the pressure chamber C. ing.

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 a lock pawl described later is engaged are formed on the inner circumferences of the openings 23 and 24 of the first and second 22, respectively. 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 frame 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. A gas introduction groove 300 communicating the supply chamber R and the working space Q is formed near one side of the partition wall 304, and an exhaust hole penetrating the outer peripheral wall 302 to open the working space Q to the atmosphere is formed near the other side. 305 are formed. 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, an annular axial flange 321 projecting from the inner end face of the lid 32 faces the inner peripheral wall 301 of the cylinder 30 with a predetermined gap therebetween and cooperates to form a bearing for supporting the inner diameter side of the rotor 31. Have been.

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 actuator-side engaging means of the clutch mechanism is inserted into the square hole 313 so as to be displaceable in an offset direction. Clutch key 52
Is a pawl 5 which constitutes means for engaging the pressure receiving head 521 receiving the gas pressure with the external teeth 511 of the ratchet wheel 51.
The pawl 522 is disposed toward the ratchet wheel 51. On the rear surface of the clutch key 52, a locking groove 523 orthogonal to the moving direction of the clutch key 52 is formed as shown in FIG.
Reference numeral 3 designates a locking means which engages with the ridge 309 formed facing the partition wall 304 of the cylinder 30 to hold the clutch key 52 at the initial position.

A deep groove in the radial direction is formed in the partition wall 304, and a sealing member 307 contained therein is pressed by a spring 308 embedded behind the sealing member 307, and a tip of the sealing member 307 is formed on the ring portion 311 of the rotor 31. A sliding contact seal that presses against the outer peripheral surface is configured. As shown in FIG. 1, an engagement groove 310 is formed on the tip end seal surface of the seal member 307 in parallel with the axis of the rotor 31. 315 are formed. 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 ignition of the primer 41. In this example, the gas generator 4 is configured to be 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 provided with a ratchet wheel 51 serving as 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 in which external teeth 511 on the outer periphery thereof are inclined rearward 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.

Each of the above elements is not limited to this, but is arranged in a frame in the following procedure, for example. That is, first, an assembly in which the lock mechanism 18 is assembled to one end of the reel 11 is inserted into both side openings 23 and 24 of the frame. 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 projections 190 into the attachment holes 210 of the frame 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,
The rotor 31 incorporating the clutch key 52 and the seal material 314 and the seal ring 33 are fitted from the open end face side of the cylinder 30 and the lid 32 is attached to the cylinder 30 after the seal member 307 combined with the spring 308 is incorporated.
Screw. 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 frame via the cover 19 and the other end supported on the other side of the frame via the spring unit 20.

Next, the operation of the above embodiment will be described. FIG. 3 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, and the clutch key 52 is positioned by engaging the groove 523 behind it with the ridge 309 of the cylinder partition wall 304 (see FIG. 1). 51 are not engaged with the external teeth 511. 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.

Upon detecting the acceleration, the firing pin of the sensor 9 (see FIG. 2) fires, and the gas generator 4
When the primer 41 is ignited (see (B) in the figure) and the gas produced by the combustion of the propellant is introduced into the pressure chamber C via the supply chamber R and the gas introduction groove 300 (see (C) in the figure), The clutch key 52 receives the gas pressure from the pressure receiving head 521 and is pushed inward in the offset direction, the pawl 522 is fitted into the valley of the external teeth 511 of the ratchet wheel 51, and the rotor 31 is connected to the ratchet wheel via the clutch key 52. 51. At this point, the winding shaft 1 is connected to the actuator 3.

On the other hand, the gas pressure is controlled by the vane 312 of the rotor 31.
To push behind the vane 312, the rotor 3
Numeral 1 rotates counterclockwise around the axis as shown in FIG. 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. 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 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. 4 shows a case where the tip of the outer teeth 511 of the ratchet wheel 51 and the tip of the tip of the pawl 522 of the clutch key 52 initially collide with the worst condition among various assumed engagement conditions. The progress is shown in order. First, the pushing of the clutch key 52 by the gas pressure and the rotation of the rotor 31 simultaneously start from the initial state of FIG. 7A, and the external teeth G of FIG.
The tooth tip collision with zero occurs. 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, the rotor 31 continues to accelerate at a certain angular acceleration, and the speed of the clutch key 52 in the offset direction becomes zero. The clutch key 52 that could not be engaged in this state is advanced by a certain angle from this position, and the rotation angle becomes a1 and reaches the next external tooth G1 as shown in FIG. , From the zero speed. Then, the sum h1 of the movement distance in the offset direction obtained by the re-acceleration and the movement distance until the initial tooth tip collision always becomes greater than the distance h0. In particular, when the rotor 31 and the clutch key 52 are made of the same kind of material, 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 G1. While rotating to the angle a2 while re-acceleration, a sufficient meshing margin r is obtained as shown in the diagram (D) until the tip of the pawl 522 finally collides with the next external tooth G1. Therefore, the clutch key 52
Engages with the next external tooth G1 at worst, irrespective 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 about 38 degrees when the clutch key 52 and the rotor 31 are made of steel.

Further, the clutch key 52 is applied to the external teeth 511 of the ratchet wheel 51 when the clutch means 5 is engaged.
As shown in FIG. 1, the impact point of the impact force is located at a position away from the axis Y by the distance D due to the offset, so that most of the impact force is a rotational moment about the axis Y. The component in the axis Y direction is extremely small. As a result, the bending load applied to the winding shaft 1 by the clutch engagement can be significantly reduced.

Finally, FIG. 5 shows another embodiment in which the offset direction of the clutch key 52A is set to a direction opposite to that of the above-described embodiment, and the -D center distance is set. Even with such a configuration, the same operation as in the above embodiment can be performed. However, when the offset direction is set in the forward direction with respect to the rotation direction of the ratchet wheel 51A, it is impossible to expect that the force in the engagement direction due to the rotation of the rotor 31A acts on the clutch key 52A. Requires that the pressure receiving surface 521A of the clutch key 52A be sufficiently large so that the engaging force is obtained by the gas pressure.

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.

[0028]

According to the present invention, even when the ratchet wheel and the clutch key collide with the tooth tip, the tooth tip is easily displaced, so that a stable clutch engagement operation is always ensured. Also, by offsetting the axis of movement of the clutch key, the impact force of the clutch engagement hardly acts as a bending stress on the winding shaft, so that the shaft strength can be set low. As a result, the weight of the shaft can be reduced. It becomes possible.

[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 the details of the components of the above embodiment in an exploded manner.

FIG. 3 is an operation explanatory diagram showing the operation of the embodiment in order.

FIG. 4 is an operation explanatory diagram showing the clutch engagement operation of the embodiment in order.

FIG. 5 is a side sectional view showing a schematic configuration of another embodiment in which the offset direction of the clutch key is changed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 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 521 Pressure receiving part C Pressure chamber S Space X Movement axis Y Center axis

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-60-45449 (JP, A) 51-112023 (JP, A) JP-B-59-15657 (JP, B2) West German Patent Application Publication 2620067 (DE, A1) West German Patent Application Publication 3531856 (DE, A1) West German Patent Application Publication 3215928 (DE, A1) A1) West German Patent Application Publication 2535380 (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 is provided, wherein the clutch means comprises a ratchet wheel attached to the shaft, and a clutch key movably supported by the rotating element, wherein the clutch key has its moving axis aligned with the center of the ratchet wheel. Direction is made in a direction intersecting the axis at a predetermined interval, and the pressure receiving portion is arranged facing the pressure chamber. A rotary actuator actuated pretensioner, characterized in that: