JP2828804B2 - Acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Acceleration sensors of this type are often used to measure the acceleration in the longitudinal direction of an automobile. Based on the measured acceleration, an effective braking is performed, for example, at a sudden stop, or By controlling the suspension during deceleration and acceleration, it becomes possible to suppress sinking and lifting of the seat.

As such an acceleration sensor, conventionally,
It is widely known that a piezoelectric element incorporates a piezoelectric element.However, the output value of a piezoelectric acceleration sensor must be amplified by an amplifier because the voltage output obtained from the piezoelectric element is small. There was a problem that the total cost was considerably high.

On the other hand, an optical acceleration sensor disclosed in Japanese Patent Application Laid-Open No. 56-8557 has a pendulum plate which has a weight and whose deflection angle changes according to acceleration, a density filter and a slit group having a predetermined pitch. Is provided, and light is radiated onto the light, and the transmitted light is detected by a light receiving element such as a phototransistor and converted into an electric signal. Since the number of slits can be detected, the acceleration corresponding to the deflection angle can be measured, and there is no need to amplify the output value with an amplifier. Therefore, the conventional proposal has an advantage that cost can be reduced as compared with a general piezoelectric acceleration sensor.

[0005]

However, the above-mentioned conventional proposals are not without problems. That is, when the vehicle shifts from a deceleration state or an acceleration state to a stop state or a constant velocity state, a weight (a pendulum plate) that is moving due to the forward or backward acceleration acts while damping and vibrating. Since the output value returns to the initial position, the output value does not return to the initial value immediately, and after the vehicle stops or reaches a constant speed,
For a while, as a result of the acceleration sensor detecting the damped vibration, the value is output as acceleration. In short, when the vehicle shifts to the state of zero acceleration in the front-rear direction, an erroneous measured value is output, so that high reliability cannot be expected.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an inexpensive acceleration sensor that can always accurately measure the acceleration of a vehicle.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to integrate a first weight and a second weight, each of which is supported so that the position fluctuates in accordance with an acceleration, with the first weight. A first detection element, a second detection element integrated with the second weight, and a first stopper for restricting movement of the first weight from an initial position in a predetermined direction. ,
This is achieved by providing a second stopper for restricting the movement of the second weight from the initial position in the direction opposite to the predetermined direction.

[0008]

According to the above means, the accelerations in the opposite directions caused by the braking or running of the vehicle can be measured by using different weights. Since the weight is regulated by the stopper when heading toward the position, each weight can quickly return to the initial position without damping vibration.

[0009]

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

FIG. 1 is an internal configuration diagram showing an embodiment of the acceleration sensor according to the present invention, and FIG. 2 is an internal configuration diagram as viewed along the line AA in FIG.

The acceleration sensor shown in these figures is for measuring the acceleration in the front-rear direction or the left-right direction of the automobile, and is provided in a case 1 so as to be rotatable about a support shaft 2. A pair of rods 3, 4 supported by 2;
A pair of weights 5, 6 respectively attached to one end of each rod 3, 4; a pair of sliders 7, 8 respectively attached to the other end of each rod 3, 4; A pair of resistive substrates 9 and 10 arranged so as to face the sliders 7 and 8, respectively, and a pair of stoppers for restricting the rods 3 and 4 from moving from their initial positions in a specific direction. 11 and 12, and when the vehicle decelerates, the weight 5 moves in the direction of arrow P in FIG.
The weight 6 is set in such a manner that when the vehicle accelerates, the weight 6 makes a pendulum motion in the direction of arrow Q in FIG. 2 (toward the paper in FIG. 1). That is, the movement of the weight 5 from the initial position in the direction of the arrow Q is regulated by the stopper 11, and the movement of the weight 6 from the initial position in the direction of the arrow P is regulated by the stopper 12. When the weight 5 is at its initial position, the rod 3 is oriented vertically, and similarly when the weight 6 is at its initial position, the rod 4 is oriented vertically.

As shown in FIG. 2, a resistor 13 and a current collector 14 are formed concentrically on the surface of the resistor substrate 9 facing the slider 7, and the acceleration at the time of deceleration of the vehicle is provided. When the weight 5 changes its position in accordance with the above, the slider 7 following the rotation of the rod 3 comes into sliding contact with the resistor 13 and the current collector 14, so that the resistance value corresponding to the deflection angle of the rod 3 is measured. Output from the terminal 15. Similarly, a resistor and a current collector (not shown) are formed concentrically on the surface of the resistor substrate 10 facing the slider 8, and the weight 6 is positioned in accordance with the acceleration at the time of acceleration of the vehicle. When it fluctuates, rod 4
A voltage or a divided voltage corresponding to the swing angle of the output can be output.

That is, in the acceleration sensor, when the vehicle decelerates, the relative position between the slider 7 and the resistor 13 on the resistance substrate 9 changes according to the acceleration, and when the vehicle accelerates, the slide position changes according to the acceleration. Since the relative position between the moving element 8 and the resistor on the resistance board 10 changes, the acceleration of the vehicle at the time of deceleration or acceleration can be converted into a voltage and measured. And
This acceleration sensor can be regarded as a variable resistor, and it is not necessary to amplify the output value with an amplifier. Therefore, the cost can be greatly reduced as compared with the piezoelectric acceleration sensor.

Since the acceleration sensors are provided with stoppers 11 and 12 for regulating the weights 5 and 6 at their respective initial positions, the vehicle shifts from a deceleration state to a stop state and the weight 5 is moved to its initial position. When moving to the position, the weight 5 is restricted by the stopper 11 so that no damping vibration is performed. Similarly, when the vehicle shifts from the acceleration state to the constant velocity state and the weight 6 moves to its initial position, the weight 6 Does not perform damped vibration because it is restricted by the stopper 12. In other words, in this acceleration sensor, when the vehicle shifts to a state of zero acceleration in the front-rear direction, the weights 5 and 6 quickly return to the initial position, and are caused by damped vibration of the weight as in the conventional proposal (optical acceleration sensor). Since there is no need to worry about outputting wrong measurement values, reliability is increased.

FIG. 3 is an internal configuration diagram showing another embodiment of the acceleration sensor according to the present invention, and FIG. 4 is an internal configuration diagram viewed along line BB in FIG. 3, corresponding to FIGS. The parts are denoted by the same reference numerals.

The acceleration sensor shown in FIGS. 3 and 4 has sliders 7 and 8 attached between the support shaft 2 and the weights 5 and 6 of the rods 3 and 4 suspended on the support shaft 2, respectively. Since the resistance substrates 9 and 10 can be arranged below the support shaft 2 and the rods 3 and 4 are shortened, there is an advantage that the height dimension can be reduced as compared with the above embodiment.

FIG. 5 is an internal configuration diagram showing still another embodiment of the acceleration sensor according to the present invention, and FIG. 6 is an internal configuration diagram viewed along line CC of FIG.

The acceleration sensor shown in FIGS.
6, a guide rod 17 that is divided into a narrow portion and a wide portion by a step 17a, a guide rod 18 that is divided into a narrow portion and a wide portion by a step 18a, A pair of weights 19 and 20 respectively inserted through the narrow portions of the rods 17 and 18, a pair of sliders 21 and 22 respectively mounted on the bottom surfaces of the weights 19 and 20, and the weight 1
Coil springs 23 and 24 for urging the weight 9 from both sides, coil springs 25 and 26 for urging the weight 20 from both sides,
A resistor 27 for slidingly contacting the sliders 21 and 22 and a resistor substrate 29 on which a current collector 28 is formed are provided. The initial positions of the weights 19 and 20 are set at positions where they come into contact with the step portions 17a and 18a by the urging forces of the coil springs 23 and 25, respectively, as shown in FIG.
The movement of the weight 19 from its initial position to the wide portion of the guide rod 17 is restricted, and similarly, the movement of the weight 20 from its initial position to the wide portion of the guide rod 18 is restricted.

That is, when the vehicle decelerates (or accelerates).
The weight 19 slides along the narrow portion of the guide rod 17 according to the acceleration of the vehicle, and when the vehicle accelerates (or decelerates)
The weight 20 slides along the narrow portion of the guide rod 18 in accordance with the acceleration of the weights 19 and 20.
Slides, the relative position between the sliders 21 and 22 and the resistor 27 changes, so that the acceleration of the vehicle at the time of deceleration or acceleration can be converted into a voltage and measured as in the previous embodiment. . Further, when the vehicle shifts to the state of zero acceleration in the front-rear direction, the weights 19, 20 can quickly return to the respective initial positions subject to the regulation of the steps 17a, 18a. Thus, a highly reliable acceleration sensor that does not have a fear of outputting an erroneous measured value due to the damped vibration of the acceleration sensor is obtained.

In each of the embodiments described above, the acceleration sensor using the principle of the variable resistor has been exemplified. However, the present invention can be applied to an optical or magnetic acceleration sensor. Further, it is possible to measure the acceleration in the width direction instead of the front-rear direction of the vehicle by using the acceleration sensor according to the present invention.

[0021]

As described above, the acceleration sensor according to the present invention measures accelerations in opposite directions caused by braking or running of the vehicle using different weights, and when the acceleration shifts to a state of zero, each weight is measured. Can be quickly returned to the initial position under the restriction of the stopper, so there is no risk of outputting erroneous measured values due to the damped vibration of the weight, and the acceleration of the vehicle can always be measured accurately, In addition, since it is not necessary to amplify the output value with an amplifier, there is an excellent effect that the cost can be significantly reduced as compared with the piezoelectric acceleration sensor.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram showing one embodiment of an acceleration sensor according to the present invention.

FIG. 2 is an internal configuration diagram viewed along the line AA in FIG. 1;

FIG. 3 is an internal configuration diagram showing another embodiment of the acceleration sensor according to the present invention.

FIG. 4 is an internal configuration diagram viewed along line BB in FIG. 3;

FIG. 5 is an internal configuration diagram showing still another embodiment of the acceleration sensor according to the present invention.

6 is an internal configuration diagram viewed along the line CC in FIG. 5;

[Explanation of symbols]

 2 Support shaft 3,4 Rod 5,6 Weight 7,8 Slider (Detection element) 9,10 Resistance board 11,12 Stopper 17,18 Guide rod 17a, 18a Step (Stopper) 19,20 Weight 21,22 Slider (detection element) 29 Resistance board

Claims (1)

(57) [Claims] 1. An acceleration sensor attached to a vehicle for measuring the acceleration of the vehicle, wherein the first weight and the second weight are respectively supported so that a position is changed according to the acceleration.
Weight, a first detection element integrated with the first weight, a second detection element integrated with the second weight, and a predetermined direction from an initial position of the first weight. A first stopper for restricting the movement of the second weight, and a second stopper for restricting the movement of the second weight from an initial position in a direction opposite to the predetermined direction. Acceleration sensor.