JPH0747919A - Rotary actuator operation pretensioner - Google Patents

Abstract

PURPOSE:To prevent decrease of actuator driving force caused by a winding shaft side engaging means interfering with a cylinder in a pretensioner using a rotary actuator as its driving means. CONSTITUTION:This rotary actuator operation pretensioner is composed of a winding shaft side engaging means 21 added to a seat belt winding shaft 2 of a retractor, a cylinder housing 30 demarcating the space enclosing the winding shaft side engaging means 21, a rotor 3, an actuator 3 having the winding shaft side engaging means 21 and a freely detachable rotor side engaging means and a gas generator which supplies gas for driving the actuator 3. A bushing 36 is inserted between the cylinder housing 30 and the winding shaft side engaging means 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretensioner attached to a retractor of a seat belt device for tightening a belt in an emergency, and more particularly to a structure of a connecting portion between the pretensioner and the retractor.

[0002]

2. Description of the Related Art A vehicle such as an automobile is provided with a seat belt device for restraining an occupant's body on a seat. In this seat belt device, a pretensioner is provided as a means for detecting an excessive acceleration applied to the vehicle in an emergency such as a collision of the vehicle and tightening the loosely mounted belt to improve the restraining effect. When the pretensioner is attached to the retractor that constitutes the belt tightening means, the pretensioner can be connected to the belt winding shaft via the clutch mechanism so as not to interfere with the normal operation of the retractor. Many proposals have been made to use a gas pressure-operated rotary actuator for the drive unit of the pretensioner.

In such a rotary actuator as a drive unit, a clutch mechanism is arranged on the inner diameter of the rotor, the mechanism is a ratchet wheel attached to a seat belt winding shaft, and a movable rotor side engaged with the ratchet wheel. There is a technique disclosed in German Published Patent No. 2505626, which is composed of vanes.

[0004]

By the way, the rotational speed of the seat belt winding shaft during the operation of the retractor is slow, whereas the rotational speed of the winding shaft during the operation of the pretensioner is several milliseconds. It is abrupt as it rotates several times within, and the rotation force is also large. Therefore, when adopting the configuration disclosed in the above specification, if the seat belt take-up shaft is precisely and firmly supported by the retractor frame or the component of the pretensioner, the take-up shaft is prevented from swinging during operation of the pretensioner. However, when the shaft is supported by the emergency lock mechanism (ELR) or the plastic case of the take-up spring unit, the take-up shaft during pretensioner operation is sufficient even if the support strength is sufficient during normal retractor operation. It is not always sufficient to prevent runout of the rotary actuator, and in extreme cases, the outer teeth of the ratchet wheel fixed to the take-up shaft bite into the components of the actuator of the pretensioner, rotate while scraping, and drive the rotary actuator. May diminish power.

The present invention has been devised in view of the above circumstances. In a pretensioner in which a rotary actuator is used as a driving means and a seat belt winding shaft of a retractor is driven through a clutch mechanism, the clutch mechanism is used. It is an object of the present invention to prevent reduction of the actuator driving force due to interference between the winding shaft side engaging means and the cylinder at the introduction portion of the winding shaft side engaging means configured into the rotary actuator cylinder.

[0006]

In order to solve the above problems, the present invention relates to a winding shaft side engaging means attached to a seat belt winding shaft and surrounding the winding shaft side engaging means. A cylinder defining a space, the space provided in the cylinder dividing the space into an operation space and an engagement space for accommodating the winding shaft side engaging means, and having a pressure receiving portion in the operation space. A rotor having a connecting portion between the working space and the engagement space,
A rotary actuator operating pretensioner comprising a rotor-side engaging means that can be engaged and disengaged with the winding-shaft-side engaging means through the connecting portion, and a gas generator that supplies a driving gas to the operating space. A bush is disposed in the introduction portion of the side engaging means into the cylinder, and is inserted between the cylinder and the winding shaft side engaging means.

[0007]

In the rotary actuator actuating pretensioner according to the present invention having such a configuration, the winding shaft side engaging means is introduced into the cylinder between the cylinder and the winding shaft side engaging means. During operation of the pretensioner, the inserted bush rotates together with the member with the larger sliding friction resistance and rotates the winding shaft side engaging means while rotating relative to the member with the smaller sliding resistance. It functions as a bearing that supports the rotation of the winding shaft, preventing the shaft run-out of the winding shaft and preventing the rotation resistance from increasing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this rotary actuator actuated pretensioner includes a retractor R.
The seat belt winding shaft 2 has a winding shaft side engaging means (ratchet wheel in this example) 21 and a rotor side engaging means (specifically, a clutch key described later) which can be engaged and disengaged with the winding shaft side engaging means 21. It is composed of an actuator 3 and a gas generator 4 which supplies a driving gas to the actuator 3. The actuator 3 has a frame 10 of the retractor R at one end thereof.
The retracting spring unit 12 of the retractor R is attached to the other end of the actuator 3 by riveting.

As shown in FIG. 3, the actuator 3 is
A cylinder including a cylinder housing 30 and a cylinder lid 32 that define a space surrounding the ratchet wheel 21, and a cylinder internal space that is disposed in the cylinder and that is divided into an operating space 301 and an engagement space that accommodates the ratchet wheel 21. And a rotor 31 having a pressure receiving portion (specifically, a vane) 311 in the operating space 301 and a connecting portion (key sliding hole in this example) 313 between the operating space 301 and the engaging space, and a sliding hole. It has a ratchet wheel 21 and a rotor side engaging means (specifically, a clutch key) 22 which can be engaged and disengaged through 313. Gas generator 4
Are accommodated and arranged in the cylinder housing 30 so as to supply a driving gas to the working space 301. In the figure, reference numeral 13 indicates a lock pawl rotatably supported by the reel flange of the retractor R, and 101 indicates ratchet internal teeth on the frame 10 side with which the reverse pawl is engaged.

In accordance with the subject matter of the present invention, as shown in FIG.
A bush 36 is provided at an introduction portion (support flange in this example) 306 of the ratchet wheel 21 into the cylinder, and is inserted between the cylinder (housing 30 in this example) and the ratchet wheel 21. 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 and is fitted into the internal gear tooth-shaped recess 102 which is referred to as the external tooth 211 of the ratchet wheel 21. And is stopped against the shaft 2.

Further, each part of the pretensioner will be described in detail with reference mainly to FIG. First, the housing 30 is made of a light alloy die cast, one end surface of which is open, and a working chamber 301 surrounded by a cylindrical peripheral wall and an end wall,
Similarly, one end surface is opened, and the supply chamber 30 is surrounded by an arch-shaped surrounding wall and an end wall, and is adjacent to the working chamber 301 with the surrounding wall interposed therebetween.
2 and a lid 32 that closes the end face opening.
And the working chamber 301 is made into a substantially cylindrical closed 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 wall 303, and this serves as an accommodation support for the seal member 34. 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. This screw hole 3
Reference numeral 09 is a screw through hole 321 of the lid 32 described later, and is a fastening screw 3 for fixing the lid 32 to the housing 30.
It is for screwing 9 together. Further, an annular support flange 306 protruding from the end wall so as to surround the 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 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 key sliding hole 313 having a rectangular cross section into which the clutch key 22 is fitted is formed.

A vane 31 is provided on the pressure receiving surface side of the vane 311.
1 and an attachment portion 330 having a seal lip 331 that is continuous at both ends and an outer edge, and a hook portion 33 that is locked to notches 314 formed on both sides of the tip of the vane 311.
And a flexible sealing member 33 made of synthetic resin. When the rotor 31 rotates, the seal lip 331 is brought into pressure contact with both end surfaces (one end surface is the inner end surface of the lid 32) and the peripheral surface of the working chamber 301 by the gas pressure, so that a gap between the housing 30 and the rotor 31 is formed. Fulfills the function of sealing.

The clutch key 22 is provided with a pressure receiving head 221 that receives gas pressure and a wedge-shaped pawl 222 that constitutes a 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 is provided with a seal surface which is in pressure contact with 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, which is substantially V-shaped in cross section. And the V-shaped top portion is directed toward the gap between the ring portion 312 and the partition wall 303 so that the housing 30
In the concave portion 304 at the tip of the partition wall, it is positioned in its own shape and accommodated and supported in a lightly elastic state.

The lid 32 is made of a press steel plate, and covers the end face opening of the housing 30. The lid 32 has a substantially square working chamber cover part 323 which conforms to the end face shape of the housing 30 and a parallelogrammatic supply chamber cover part 324 which is connected to the working chamber cover part 323. It has and. At the center of the working chamber cover portion 323, a cylindrical support flange 325 that extends inward is projected, and this is shown in FIG.
As shown in, it functions as a bearing that supports the step portion on the inner diameter side of the ring portion 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.

In accordance with the subject matter of the present invention, a bearing bush 36 is provided 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 whirling of the winding shaft 2. . As shown in detail in FIG. 2, this is inserted into the inner circumference of a support flange 306 protruding into the working chamber 301 of the housing 30, and is formed by press-molding a stainless steel pipe material, and is attached to one end side. It has a collar 361 extending outward in the radial direction. In the assembled state, the collar 361 is provided with the rotor 31.
It is located between the ring portion 312 and the end surface of the support flange 306, and functions as a bush positioning and a thrust bearing.

In FIG. 3, reference numeral 4 is a gas generator, 41 is its primer, and 5 is an acceleration sensor. The gas generator 4 is provided in the supply chamber 30 of the housing 30.
It is accommodated in a tubular gas generator accommodating portion 308 that is continuously provided with the lid 2, is pressed and fixed to the bottom portion of the accommodating portion 308 via the retaining ring 44 when the lid 32 is fixed, and is screwed to the outside of the bottom portion. It faces the acceleration sensor 5. The acceleration sensor 5 has a pin 51 shown in FIG.
Is provided, and the opening at the bottom of the housing portion, into which the tip of the pin 51 is introduced when the pin 51 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.

When the acceleration is detected, the firing pin 51 of the sensor 5 shown in FIG. 1 fires, the primer 41 of the gas generator 4 is ignited, and the gas pressure generated by the combustion of the propellant such as nitrocellulose is supplied to the supply chamber 302. When the voltage is applied to the key connector 23 (see FIG. 4B),
Since the engagement by the hook 232 is released and 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 2
22 moves to a position where the ratchet wheel 21 contacts the peaks of the external 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.

As a result, 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. Start counterclockwise rotation as shown.
The back pressure chamber 301b of the working chamber 301 generated by this rotation
The pressure on the side is released into the atmosphere through the exhaust hole 307 of the housing 30, so that the generation of resistance due to the pressure increase on the side of the back pressure chamber is prevented. On the other hand, the displacement of the clutch key 22 is continued, the pawl 222 of the clutch key 22 meshes with the outer teeth 211 of the ratchet wheel 21, and the rotor 31 engages with the ratchet wheel 21 via the clutch key 22. At this point, the winding shaft 2 is connected to the actuator 3. 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.

As the winding operation of the winding shaft 2 is performed,
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 rotation is stopped. 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, the take-up shaft 2 integrated with the take-up reel 1 tries to continue to rotate due to its own inertia, and this time, as shown in FIG. The outer teeth 211 of the above push the clutch key 22 in the disengagement direction, and the winding shaft 2 is released from the rotor 31, so that 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 depends on the amount of propellant loaded in the gas generator 4, but it is about 1 / min of the rotor rotation.
It can be about 2. 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 series of operations described above, 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.

During these operations, one end of the retractor R is supported by the plastic cover of the emergency lock mechanism (ELR) 11 and the other end is supported by the plastic case of the winding spring unit 12 via the winding shaft 2. Since the take-up reel 1 receives the upward force in FIG. 2 due to the reaction force associated with the winding of the belt, the ratchet wheel 21 integrated with the take-up reel 1 also rotates while receiving the upward pulling force.
As a result, the outer teeth 211 of the ratchet wheel 21 engage with the inner peripheral surface of the bush 36, and the ratchet wheel 21.
Is supported by the inner peripheral surface of the support flange 306 of the housing 30 together with the bush 36, and slides and rotates. The sliding surface at this time is the support flange 30 of the light alloy die cast.
6 is a smooth surface on the outer circumference of the stainless steel bush facing the relatively smooth surface. Therefore, the support flange 30 of the housing 30 of the outer teeth 211 of the ratchet wheel 21
Not only is the biting of the inner peripheral surface of 6 prevented, the increase in rotor rotational resistance due to this is avoided, but the frictional resistance of the sliding rotary portion is reduced.

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.

[0028]

Therefore, according to the present invention, the bush inserted between the cylinder and the winding shaft side engaging means rotates the winding shaft side engaging means to the cylinder when the pretensioner operates. Since it functions as a bearing to support and prevents shaft run-out of the winding shaft at the introduction part of the winding shaft side engaging means into the cylinder, it relatively rotates between the surfaces with smaller sliding resistance,
It is possible to prevent a reduction in actuator driving force due to an increase in rotation resistance.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention including a retractor in a partial cross section.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is an exploded perspective view of the entire components of the above embodiment.

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 311 vane

Claims (1)

[Claims] 1. A take-up shaft side engaging means attached to a seat belt take-up shaft, a cylinder defining a space surrounding the take-up shaft side engaging means, and a cylinder disposed inside the cylinder. A rotor that divides a space into an operating space and an engaging space that accommodates the winding shaft side engaging means, has a pressure receiving portion in the operating space, and has a connecting portion between the operating space and the engaging space. ,
A rotary actuator actuation pretensioner comprising rotor-side engagement means that can be engaged and disengaged with the take-up shaft-side engagement means through the communication section, and a gas generator that supplies drive gas to the actuation space, In the introduction portion of the side engaging means into the cylinder,
A rotary actuator actuation pretensioner, characterized in that a bush is disposed so as to be interposed between the cylinder and the winding shaft side engaging means.