JPS601425Y2 - Acceleration sensor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an acceleration sensor most suitable for seat belt devices of automobiles, etc.

In a seat belt device for an automobile, an end portion of an occupant restraining webbing is forcefully wound around a winding device attached to a vehicle body.

This winding device is equipped with an acceleration sensor, which allows the occupant to unwind the webbing at will while the vehicle is normally running, but in the event of a vehicle emergency, the webbing is securely restrained to improve occupant safety. It has become.

This acceleration sensor generally transmits the output from the inertial member to a lock bar, and the lock bar engages with a ratchet wheel fixed to the winding shaft, thereby stopping the unwinding rotation of the ratchet wheel and the winding shaft. It looks like this.

However, in such a conventional acceleration sensor, the lock bar is directly mounted on the inertial member, and therefore, depending on the weight of the lock bar, the responsiveness when an acceleration is applied may be reduced.

The present invention takes the above facts into consideration and aims to provide an acceleration sensor with excellent responsiveness and high reliability.

In the acceleration sensor according to the present invention, the output lock bar is placed on the upper end of the support rod, and the inertia member fitted on the support rod is swingably supported by a step protruding from the middle of the support rod. At the same time, the inertia member is separated from the lock bar in the normal state,
This structure improves responsiveness by pushing up the lock bar only when the inertial member swings due to acceleration.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the acceleration sensor of the present invention is applied to a webbing retractor in a seat belt device for an automobile.

In the winding device 10, a frame 1112 is fixed to the vehicle body 16 through a mounting port 14, and a winding shaft 20 is pivotally supported on a pair of legs 18 extending parallel to each other from both sides of the frame 12. (However, one leg 1 is shown in Figure 1.)
8 is omitted from illustration.

) This winding shaft 20 is biased in the winding direction of the webbing 22 by a clockwork spring (not shown), so that the ends of the webbing 22 are wound onto the winding shaft 20 in a layered manner.

The other end (not shown) of the webbing 22 is used to restrain the occupant, and can be attached to the occupant using a tongue plate, a buckle device, or the like.

A ratchet wheel 24 is fixed to the winding 1M20, and this ratchet wheel 24 corresponds to a locking member 28 that is pivotally supported by the leg portion 18 and the hebine 26.

This lockper 28 is separated from the ratchet wheel 24 due to its own weight under normal running conditions of the vehicle, but when it is pushed up by the acceleration sensor 30 and rotates around the pin 26, the ratchet wheel 24 is separated from the ratchet wheel 24 as shown in FIG. 24 to stop the webbing unwinding rotation of the ratchet wheel 24 and the take-up shaft 20.

A support rod 34 is fixed at the lower end of the acceleration sensor 30 to a bracket 32 extending between the legs 18 with its axis perpendicular.
It is placed on the upper end of the

A flange portion 36 that increases the radius of the support rod 34 is integrally formed near the upper end of the support rod 34, and the top surface of this portion 36 is a stepped portion 38.

An inertial member 40 is suspended from this stepped portion 38 .

That is, the inertial member 40 has a cylindrical shape with a through hole 42, and an upper end portion 44 is placed on the stepped portion 38.

A gap is formed between the inner diameter of the reduced diameter portion 44 and the outer diameter of the upper end of the support rod 34, so that the inertial member 40 swings as shown in FIG. 2 when subjected to acceleration. However, even during this swinging, the reduced diameter portion 44 is attached to the support rod 34.
Care has been taken to ensure that it does not fall off.

Here, the inertia member 40 is in a state where its axis is substantially the same as the axis of the support rod 34, that is, when the acceleration is less than a predetermined value, the top surface of the reduced diameter portion 44 is separated from the bottom surface of the locking member 28. As shown in FIG. 2, when a large acceleration is applied, the reduced diameter portion 44 comes into contact with the bottom surface of the lock par 28, causing the lock par 28 to rotate around the pin 26.

Note that a thick portion 46 is provided at the lower end of the inertial member 44 to increase the rocking force of the inertial member 40 when it receives acceleration.

In this embodiment configured as described above, the webbing 22 is unwound from the winding shaft 20 and attached when the occupant gets on the vehicle.

In this case, since no acceleration is acting on the conformable member 40, the locking member 28 is separated from the ratchet wheel 24 and does not hinder the unwinding of the webbing 22.

The same applies to the normal running state of the vehicle.

If the vehicle is in an emergency situation such as a collision, the inertial member 4
0 as shown in FIG. Since the webbing unwinding rotation is stopped, the occupant is securely restrained and safety is guaranteed.

When the lockper 28 is pushed up by the inertial member 40,
Since the inertia member 40 comes into contact with the lockper 28 after swinging by a predetermined angle, the lockper 28 is not subjected to its own weight at the initial stage of swinging, and the lockper 28 can be operated quickly.

In addition, in the normal running state of the vehicle, the reduced diameter portion 44 of the inertia member 40 is separated from the lockper 28, so the inertia member 40
There is no abnormal noise caused by vibration or the like between 0 and the lock par 28.

As explained above, since the acceleration sensor according to the present invention has a support rod and an inertia member fitted into the support rod, the movement of the inertia member when standing up is quick and has excellent responsiveness, resulting in an excellent effect of improving reliability. have

Further, since the inertial member contacts the locking member only when necessary, it is possible to prevent the occurrence of abnormal noises, and furthermore, it has the advantage of being easy to assemble.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the acceleration sensor according to the present invention, and FIG. 2 is a partial view showing the operating state of FIG. 1. 28...Track bar, 30...Acceleration sensor, 34...Support rod, 38...Step part, 40...Inertia member, 42 ......Through hole.

Claims (1)

[Scope of utility model registration request] An output lock bar is placed on the upper end of the support rod that stands up to the frame, and an inertia member having a through hole in the axis is fitted onto the support rod. An acceleration sensor is swingably supported by a protruding step, and the top surface of this inertial member is sized to come into contact with the lock bar when swinging.