JP2641697B2 - Shock sensing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact sensing device, and is used as a sensor for starting an impact safety system such as an air back and a seat belt tensioner.

[0002]

2. Description of the Related Art Conventionally, as this kind of impact sensing device,
Japanese Patent Application Laid-Open No. 60-248456 is known. This is due to the biasing force of the spring due to the movement of the sensing weight.
The output member is moved by the urging force of a spring by pressing and rotating the rod in opposition, rotating the rotation shaft by the rotation of the rod and releasing the engagement between the rotation shaft and the ignition pin.

[0003]

However, with the above-described impact sensing device, the impact (instantaneous moment) of a very short time such as when traveling on a rough road is taken advantage of by utilizing the fluid damper effect due to the clearance between the sensing weight and the housing. Malfunctions) to prevent malfunctions. For this reason, there is a disadvantage that the characteristics change due to various conditions such as a temperature change, and stable performance cannot always be obtained.

[0004] Therefore, an object of the present invention is to make it possible to prevent malfunctions that always have stable performance regardless of various conditions such as temperature changes.

[0005]

In order to solve the above-mentioned technical problems, the technical means adopted in the present invention is a housing and a weight supported in the housing so as to be swingable at a position offset from the center of gravity. An output member that is engaged with the weight, is restricted in movement, is disengaged by the swing of the weight, and moves in the protruding direction, and the output member is disposed between the housing and the output member. The weight is urged in the protruding direction and the weight is moved to the initial position.
And a spring for holding the spring.

[0006]

The above technical means operates as follows. Weight is held in the initial position via the engagement of the output member and the weight by the biasing force of the spring at all times. When acceleration is applied in this state, the spring swings against the urging force of the spring. Thereby, the engagement between the output member and the weight is released, and the output member moves in the protruding direction.

As described above, the damper effect is obtained by the biasing force of the spring and the moment of inertia acting on the weight. The damper effect prevents a malfunction due to an impact for a very short time such as when traveling on a rough road. Therefore, there is no characteristic change due to various conditions such as temperature change, and stable performance can always be obtained.

[0008]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a weight 2 is provided in a housing 1. The weight 2 includes a pair of disc-shaped large diameter portions 2a and a semicircular cam portion 2b formed between the large diameter portions 2a.
A groove 1a is formed in the housing 1, and the weight 2 is supported by the pin 3 at a position offset from the center of gravity so as to be rotatable and movable, that is, swingable .

[0010] The housing 1 includes a firing pin 4a.
Is rotatably supported by a pin 5. A spring 6 is disposed between the firing lever 4 and the housing 1, and the firing lever 4 is turned clockwise as shown in FIG. 2, ie, the direction in which the firing pin 4 a projects from the window 1 b of the housing 1. Is always energized. Also, the firing lever 4
Is formed with an engaging portion 4b which can be disengaged from the cam portion 2b. By the engagement between the cam portion 2a and the engagement portion 4b, the rotation of the firing lever 4 in the clockwise direction as shown in FIG. 2 is restricted against the urging force of the spring 6, and the weight 2 swings. Is regulated. (The regulation of the weight 2 is substantially regulated by the urging force of the spring 6.) Next, the operation will be described.

In the state shown in FIG. 2, when an acceleration (shock) of a predetermined magnitude and for a predetermined time or more is applied in the direction A,
As shown in FIG. 3, the weight 2 rotates clockwise in FIG. 2 while rotating the firing lever 4 counterclockwise in FIG. 2 against the urging force of the spring 6, and moves downward in FIG. Moving, ie, the second illustrated clockwise direction about the pin 3
Rocks. The swinging of the weight 2 releases the engagement between the cam portion 2b and the engaging portion 4b, whereby the firing lever 4 is moved clockwise in FIG. 3 by the urging force of the spring 6 as shown in FIG. By rotating, the firing pin 4a is driven out of the window 1b. Such firing of the firing pin 4a is performed only when an acceleration of a predetermined magnitude and for a predetermined time or more is applied, and an acceleration of less than that, that is, an impact for a very short time (an instantaneous impact)
In the above, the urging force of the spring 6 and the weight 2 act on
It is absorbed by the Ku moment of inertia (damper effect) malfunction prevention is made.

As described above, since the damper effect is obtained by the biasing force of the spring 6 and the inertia moment acting on the weight 2 , there is no characteristic change due to various conditions such as temperature change, and stable performance can be always obtained. In addition, since the number of components is small, the size of the weight 2 can be increased, so that the resolution of the acceleration that can be sensed is high and the launching energy of the firing pin 4a can be increased. Furthermore, it can be assumed very inexpensive in terms of cost it is possible to manage the dimensional accuracy over conventional securing easy and reliable.

The urging force of the spring 6 and the weight 2
By simply changing the offset amount of the acceleration, the value of the acceleration which can be easily sensed can be changed. Further, the above-mentioned impact sensing device is arranged in two sets so as to be symmetrical with respect to a point, and the input of the inertial weight when mounted on a handle pad or the like is made as uniform as possible to improve the redundancy.

[0014]

According to the present invention, the weight is swingably supported at a position offset from the position of the center of gravity. Erroneous operation can be prevented, and there is no characteristic change due to various conditions such as a temperature change, and stable performance can be always obtained. Further, since the number of components is small, the size of the weight can be increased, so that the resolution of the acceleration that can be sensed is high and the launching energy of the output member can be increased. Furthermore, it can be assumed cost a very inexpensive also it is possible to manage the dimensional accuracy is easily secured and reliable than before.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an impact sensing device according to the present invention.

FIG. 2 is a longitudinal sectional view of the impact sensing device.

FIG. 3 is a longitudinal sectional view corresponding to FIG. 2 and illustrating an operation state of the shock sensing device.

FIG. 4 is a longitudinal sectional view corresponding to FIG. 2 and illustrating an operation state of the shock sensing device.

[Explanation of symbols]

 Reference Signs List 1 housing 2 weight 4 firing lever (output member) 6 spring

Claims (1)

(57) [Claims] 1. A housing, a weight rotatably supported in a position offset from a center of gravity in the housing, and a movement restricted by engaging with the weight and disengaged by the swing of the weight. An output member that moves in the protruding direction, and is disposed between the housing and the output member to urge the output member in the protruding direction and
A spring for holding the weight in an initial position .