JPH0449582Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an acceleration detection device used for detecting acceleration in a vehicle or the like.

[Conventional technology and its problems]

Conventionally, this type of acceleration detection device is known, for example, as disclosed in Japanese Utility Model Application Publication No. 55-170668 and Japanese Patent Publication No. 58-35891. In the former, the inertial body receives a spring load, while in the latter, A ball is placed on a slope with a constant slope. When a predetermined deceleration (negative acceleration) occurs, in the former, the inertia body tilts due to inertia and operates the switch, and in the latter, the ball rolls due to inertia and closes the valve device. . However, it takes a considerable amount of time to operate the switch or close the valve device as described above after the predetermined deceleration occurs, resulting in a detection delay.

FIG. 2 shows an acceleration detection device previously proposed by the present applicant. To explain this, in FIG. have A roller 4 made of a permanent magnet is disposed in this cavity 3 so as to be able to roll freely, and normally rests against the lower end wall of the cavity 3 as shown in the figure under the action of gravity.

The bottom surface 3a of the space 3 is inclined at a constant angle θ with respect to the horizontal line H, as shown by a chain line B. This angle θ
is determined according to a predetermined deceleration (for example, 0.6 g). That is, in the illustrated state, the reed switch 5 fixed to a part of the main body 1 is closed by the magnetic force of the roll 4, but when the vehicle equipped with this acceleration detection device is braked and a predetermined deceleration is reached. When it reaches this point, the roll 4 begins to move upwardly to the right on the bottom surface 3a due to inertia.

As a result of the above, the roll 4 is moved away from the reed switch 5, the magnetic force reaching the reed switch 5 becomes smaller, and the reed switch 5 is switched to the open position.However, in reality, even if the roll 4 reaches a predetermined deceleration, the roll 4 does not start rising. That is, the roll 4 moves the reed switch 5 due to its magnetic force.
A magnetic attraction force is generated between the contact points of the roll 4 and the roll 4 is pressed against the lower end wall of the cavity with a certain force not only by gravity but also by the magnetic attraction force. Therefore, even if a predetermined deceleration occurs, it does not roll upward, and it only starts rolling upward when the deceleration becomes large enough to overcome the magnetic attraction force. This makes it impossible to accurately detect a predetermined acceleration (negative). The above description deals with the case where deceleration occurs, but if the direction of the diagram is reversed, acceleration (positive) is detected, but the same drawbacks occur.

It is also conceivable to provide the reed switch 5 at the position shown by the dotted line, but even in this case, the following drawbacks still occur.

That is, in this case, when a predetermined deceleration occurs, the roll 4 moves upward and comes into contact with the upper end wall of the cavity 3. As a result, the reed switch 5 is closed by the magnetic force of the roll 4, and it is detected that a predetermined deceleration has occurred.After this, even if the vehicle becomes less than the predetermined deceleration, the roll 4 closes the reed switch 5.
It immediately rolls downward due to the magnetic attraction between the
Do not open reed switch 5.

[Problem that the invention attempts to solve]

The present invention was made in view of the above problems, and provides an acceleration detection device that can accurately detect a predetermined acceleration (positive or negative) without being affected by the attraction force between the magnet and the reed switch by reducing the detection delay. The purpose is to provide.

[Means for solving problems]

The above purpose is to provide a main body having a slope inclined with respect to a horizontal plane according to the acceleration to be detected, a magnet that can be moved along the slope by the action of acceleration, and a reed switch that is activated in response to the movement of the magnet. This is achieved by an acceleration detecting device having the reed switch provided on the side in the moving direction of the magnet, and in which the slope of the slope on the reed switch side is increased by a predetermined value.

[Effect]

When the specified acceleration is reached, the magnet does not receive any attraction between it and the reed switch, so it reacts accurately and moves toward the reed switch, and the slope becomes steeper, so it stops midway up. Activate the reed switch. Therefore, the predetermined acceleration can be accurately detected.

When the acceleration falls below a predetermined value, since there is no attraction between the magnet and the reed switch, the magnet immediately descends down the slope, leaving the reed switch in a non-operating state. Therefore, it is possible to accurately detect when the predetermined acceleration is reached and when it falls below this.

〔Example〕

FIG. 1 shows an acceleration detection device according to an embodiment of the present invention, and parts corresponding to those in FIG. 2 are given the same reference numerals.

That is, although a cavity 11 is formed in the main body 10, the slope of the bottom surface 12 of the cavity 11 is different between the lower side and the upper side. That is, the bottom surface 11 consists of a lower slope 12a and an upper slope 12b, and as shown by chain lines B ₁ and B ₂ , the angle of inclination of the former with respect to the horizontal line H is smaller, θ, but this is due to the acceleration shown in FIG. They are the same because they detect the same deceleration as the detection device. The inclination angle of the upper slope 11b is dθ as shown by the chain line _B2 .
This is, for example, 3° to 5°. Further, the reed switch 5 is provided on the upper end wall side of the space 11.

The embodiment of the present invention is configured as described above, but
Next, this action, effect, etc. will be explained.

When the brakes are applied to a vehicle equipped with this acceleration detection device and a predetermined deceleration (for example, 0.6g) is reached, the roller 4 is no longer receiving magnetic attraction force from the reed switch 5 from the state shown in the figure. Therefore, it immediately begins to move upward to the right. At this time, the rising speed is higher than before and when it reaches the position shown by the dashed line, that is, the starting end of the upper slope 12b, the slope of this slope 12b changes to the lower slope 1 that has been rolling so far.
Since the inclination of 2a is greater by dθ, the movement of roller 4 is stopped, and reed switch 5 is then closed.

The reed switch 5 is connected, for example, to a solenoid of an electromagnetic valve device for determining the starting pressure for pressure reduction proportional control of the brake force, and thereby the control can be performed appropriately. Further, when the vehicle deceleration becomes smaller than the predetermined deceleration, the roller 4 immediately rolls downward and opens the reed switch 5. This is because the magnetic attraction force is sufficiently small because it is sufficiently far away from the reed switch 5.

Although the embodiments of the present invention have been described above, the present invention is of course not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the embodiments described above, the reed switch 5 is provided on the upper wall side of the cavity 10, and is normally left open and closed when a predetermined deceleration occurs, but the reed switch 5 may be reversed. That is, it may be normally closed and opened when a predetermined deceleration occurs.

Further, in the above embodiment, the slope of the bottom surface 12 of the space 11 is changed like a polygonal line, but instead of this, it may be changed into a downwardly convex curved line.

[Effect of idea]

As described above, according to the acceleration detection device of the present invention, the time from when a predetermined deceleration or acceleration occurs until the reed switch is switched is greatly shortened, and various controls related to this reed switch can be controlled. Can be done accurately.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of an acceleration detecting device according to an embodiment of the present invention, and FIG. 2 is a partially cutaway front view of a conventional acceleration detecting device. In the figure, 4... Magnetrol, 5
... Reed switch, 12a ... Lower slope, 12
b...Upper slope.

Claims (1)

[Scope of utility model registration request] a main body having a slope inclined with respect to a horizontal plane according to the acceleration to be detected; a magnet disposed so as to be movable along the slope due to the action of the acceleration;
An acceleration detection device having a reed switch that operates according to the movement of the magnet, wherein the reed switch is provided on the side in the direction of movement of the magnet, and the slope on the reed switch side is increased by a predetermined value. .