JPH0233179Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an acceleration sensor that is most suitable for a seat belt device for protecting vehicle occupants in an emergency.

[Background technology]

Acceleration sensors are used in automobile seat belt devices to prevent the webbing for restraining an occupant from being pulled out in the event of a vehicle emergency.

That is, in an automobile seat belt device, one end of the webbing that is worn by an occupant when riding the vehicle is wound up and stored in a winding device attached to the vehicle body. This winding device houses an acceleration sensor,
Under normal vehicle conditions, the webbing can be pulled out and the occupant can assume any driving position; however, in an emergency, the webbing is prevented from being pulled out and the occupant is restrained, thereby ensuring safety. ing.

This acceleration sensor has a ball placed at a stop position, and when an acceleration of more than a predetermined value is applied, the ball climbs up the slope and activates the actuator, thereby stopping the webbing retrieval device. It's getting old.

By the way, as shown in FIG. 5, the acceleration sensor 10 is generally accommodated in the take-up device 12 at the position shown in the figure. It is preferable for the width L1 of the winding device 12 to be as narrow as possible in view of placement in the vehicle.

However, in the width dimension L1 of the winding device 12,
The dimension of the part where the webbing 14 is wound is L2
The minimum dimension is limited by the width of the webbing 14 and other mechanisms, and the minimum dimension L3 of the portion in which the acceleration sensor 10 is accommodated is limited mainly by the diameter of the ball 16.

Since the minimum width of the webbing is regulated for safety reasons, there is currently a limit to reducing the size of this portion. Furthermore, the minimum width of the dimension L3 is determined by the diameter of the ball 16 as described above, but since the ball 16 must have the required mass, it is difficult to shorten this dimension. It had been. Therefore, conventionally, the acceleration sensor 10
In the structure in which the winding device 12 is housed as shown in FIG. 5, it has been difficult to shorten the width L1 of the winding device 12.

[Purpose of invention]

The present invention takes the above-mentioned facts into account and aims to provide an acceleration sensor that can shorten the width of the winding device.

[Structure of the idea]

The acceleration sensor according to the present invention includes: an elongated ball case having a slope on which the ball climbs when an acceleration is applied; a plurality of balls arranged in the ball case along the longitudinal direction of the ball case; an actuator actuated by the climbing ball. This allows the width of the acceleration sensor to be shortened. Therefore, when applying this acceleration sensor to a winding device,
It is possible to shorten the width of a portion of the winding device in which the acceleration sensor is accommodated, thereby reducing the width of the winding device.

[Example of idea]

1 to 4 show a first embodiment of an acceleration sensor according to the present invention. In this acceleration sensor, balls 18 as rolling elements are mounted in a ball case 2.
Two are stored in 0.

A long hole 22 perpendicular to the axis is bored in the center of the ball case 20, and two balls 18 are placed on this long hole 22 in contact with each other.
This is the stopping position for the balls 18. The ball case 20 is formed with an inclined surface 24 whose height gradually increases from the upper edge of the elongated hole 22.
The ball 18 is adapted to climb up when subjected to acceleration. A bracket 26 is formed at one longitudinal end of the ball case 20, and an actuator 28 is swingably supported on this bracket via a pin 30.

A bulge 28A whose inner surface abuts against the two balls 18 is formed at the center of the actuator 28, and an elongated opening 28B is formed at the center of the bulge 28A. Further, a pole 32 bent diagonally upward into a hook shape is formed at the end of the actuator 28 on the opposite shaft support side. When the ball 18 climbs up the slope 24, the actuator 28 tilts and moves up the pole 32.
is engaged with a ratchet wheel (not shown) to stop the rotation of the winding shaft of the webbing winding device.

As shown in FIGS. 2 and 3, each part of the inclined surface 24 formed on the ball case 20 is set at a different angle of inclination. That is, the ball case 20
In the longitudinal direction, the shaft support side of the actuator 28 is set at an inclination angle θ1, as shown in FIG.
The opposite side is set at an inclination angle θ2. In addition, in the direction perpendicular to the longitudinal direction of the ball case 20,
As shown in FIG. 3, both sides are set at an inclination angle θ3. The connecting surface between the inclination angle θ3 and the inclination angle θ1 and the connecting surface between the inclination angle θ3 and the inclination angle θ2 are both smoothly connected without any step. Between these inclination angles θ1, θ2 and θ3, θ3<θ1<θ2
A relationship exists.

Next, the operation of this embodiment will be explained.

In the normal state of the vehicle, the two balls 18 are in the long hole 22.
The actuator 28
The vehicle is stopped in the state shown in FIGS. 2 and 3, and the webbing retractor can be rotated to pull out the webbing, allowing the occupant to assume any driving position.

In addition, if the vehicle is in an emergency situation such as a collision, the ball 18 will climb up the slope 24.
Immediately the actuator 28 tilts and the pole 3
2 engages with a ratchet wheel (not shown) to prevent the occupant restraining webbing from being pulled out, thereby restraining the occupant.

Next, the behavior of the two balls 18 in a vehicle emergency state will be described in detail.

In a vehicle emergency state, if acceleration is applied from the longitudinal direction of the ball case 20, the ball 1
8 climbs up an inclined surface 24 having an inclination angle of θ1 or θ2. At this time, the ball 18 climbing up the slope 24
There is only one, and the other one supports it. One ball of this embodiment is set to have half the mass of a conventional ball. Since the magnitude of the acceleration acting on the ball is the same regardless of the mass of the ball, the force possessed by each ball in this embodiment is half that of a conventional ball. Since the ball 18 of this embodiment moves with both balls in contact with each other, the resultant force is equivalent to that of a conventional ball. Therefore, no operational problems arise due to the use of two balls 18.

In addition, when acceleration acts from a direction perpendicular to the longitudinal direction of the ball case 20 in a vehicle emergency, both of the two balls 18 have an inclination angle of θ3.
Climb up the slope 24 of In this case as well, the resultant force of the two balls 18 is equivalent to that of the conventional ball, and no operational problem occurs.

The reason why the angle of inclination of the inclined surface 24 is made different in each part is to take into consideration the difference in the lever ratio based on the difference in the distance from the shaft support of the actuator 28, and also to make the direction of movement of the ball 18 different. Taking into account the differences in contact between the ball 18 and the actuator 28 due to differences, the sensitivity is the same in all directions (the actuator operates equally at the same acceleration).
This is because care has been taken to ensure that they can obtain the following.

In this embodiment, the number of balls 18 is two, and each ball 18 has a small diameter, so that the width of the acceleration sensor 36 housed in the winding device 34 can be narrowed, as shown in FIG. Therefore, the width L4 of the winding device 34 can be made narrower. Therefore, the winding device 34 is downsized and the degree of freedom in vehicle arrangement is increased, so that various effects such as easing restrictions on the layout of the vehicle interior are achieved.

In addition, in the direction perpendicular to the width of the take-up device (the direction perpendicular to the plane of the paper in Figure 4), a space is required to accommodate the wound webbing, so two balls are placed in parallel in this direction. However, there is still enough space to accommodate this. Therefore, there is no risk that other parts of the winding device will become wider due to the narrower width.

In the above embodiment, an example was shown in which two balls were provided, but it is also possible to provide three or more balls.

Further, in the embodiment described above, an example was shown in which the elongated hole 22 was provided in the center of the ball case 20, but this elongated hole is not necessarily required.

Furthermore, in the above embodiment, the inclined surface of the ball case 20 is set at a different angle of inclination in each part, but the inclined face of each part of the ball case 20 is set at the same angle of inclination, and instead, the inclined surface of each part of the ball case 20 is set at a different angle of inclination. The same effect can be obtained by forming inclined surfaces with different inclination angles.

[Effect of idea]

As explained above, in the acceleration sensor according to the present invention, a plurality of balls are arranged in the elongated ball case along the longitudinal direction of the ball case to shorten the width dimension of the acceleration sensor. This has the effect that the width dimension of the portion where the winding device is accommodated can be shortened, and therefore the width dimension of the winding device can be shortened.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the acceleration sensor according to the present invention, FIG. 1 is an exploded perspective view, FIG. 2 is a longitudinal sectional view of the ball case, and FIG. 3 is a direction orthogonal to FIG. 2. 4 is a schematic front view showing a winding device in which an acceleration sensor according to an embodiment of the present invention is housed, and FIG. 5 is a schematic front view showing a winding device in which a conventional acceleration sensor is housed. . 18...Ball, 20...Ball case, 24
... Inclined surface, 28 ... Actuator.

Claims (1)

[Scope of utility model registration request] It is operated by an elongated ball case with a slope on which the ball climbs when acceleration is applied, a plurality of balls arranged in the ball case along the longitudinal direction of the ball case, and balls that climb up the slope. An acceleration sensor equipped with an actuator and an actuator.