JP2947993B2 - 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,
Japanese Utility Model Application Laid-Open No. 62-148961, and Japanese Utility Model Application Laid-Open No.
As disclosed in Japanese Patent Publication No. 40, a device incorporating a piezoelectric element is widely adopted. In such a piezoelectric acceleration sensor, when acceleration is applied to a mass element as the vehicle decelerates or accelerates, the mass element applies a pressing force to the piezoelectric element, and a voltage output according to the force is obtained from the piezoelectric element. The acceleration can be measured.

[0004]

However, in such a piezoelectric acceleration sensor, since the voltage output obtained from the piezoelectric element is small, the output value must be amplified by an amplifier, and as a result, the total cost is considerably high. There was a problem that it became something. That is, the piezoelectric acceleration sensor requires at least an amplifier circuit and a power supply circuit thereof, and the wiring becomes complicated. Therefore, when the piezoelectric acceleration sensor is mounted on a vehicle, the cost is greatly increased.

Accordingly, the object of the present invention is to:
An object of the present invention is to provide an acceleration sensor that solves the above-described problems of the related art and does not need to amplify an output value and can suppress an increase in cost.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an acceleration sensor that is attached to a vehicle and measures the acceleration of the vehicle. The rod has a weight at one end and moves in a pendulum according to the acceleration. A fixing member rotatably supporting the other end of the rod, a magnet provided on the fixing member to attract the weight to a neutral position of the pendulum motion, and a magnet provided between the rotation center of the rod and the weight. Displacement detection means ,
And a detecting element provided in the fixing member so as to face the displacement detecting means, by the relative position of the displacement detection means and said detection element is varied in accordance with the pendulum movement of said rod, said detecting This is achieved by configuring to detect the displacement amount of the rod from the element. In addition , the object of the present invention is to provide an acceleration sensor attached to a vehicle that measures the acceleration of the vehicle, a pair of weights that slide in accordance with the acceleration, a fixed member that slidably supports these weights, Detecting means for detecting the relative position between the weight and the fixing member, and a stopper step provided on the fixing member, such that the two weights slide in opposite directions with respect to the stopper step. Achieved by regulation.

[0007]

According to the above means, when the position of the weight changes according to the direction and magnitude of the acceleration caused by braking or running of the vehicle, the relative position between the weight and the fixing member changes accordingly. Acceleration can be measured by detecting the amount of change in the relative position with the detecting means, and undesired movement of the weight is suppressed by the magnet and the stopper step, so that stable output characteristics can be obtained.

[0008]

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

FIG. 1 is an internal configuration diagram showing a first embodiment of the acceleration sensor according to the present invention, and FIG. 2 is an internal configuration diagram when FIG. 1 is viewed from the side.

The acceleration sensor shown in these figures is for measuring the acceleration in the front-rear direction or the left-right direction of the vehicle, and both ends of a support shaft 2 are fixed in a case 1 which is a fixed member. The upper end of the rod 3 is rotatably supported on the shaft 2. A weight 4 is attached to the lower end of the rod 3, and a slider 5 as an actuator is attached between the support shaft 2 and the weight 4 at the center of the rod 3. On the other hand, a resistance board 6 as a detection element is arranged on the inner side wall of the case 1 so as to face the slider 5, and the slider 5 and the resistance board 6 constitute detection means. A resistor 7 and a current collector 8 are formed concentrically on the surface of the resistor substrate 6 facing the slider 5, and when the weight 4 changes its position in accordance with the longitudinal acceleration of the vehicle, Since the slider 5 that follows the rotation of the rod 3 comes into sliding contact with the resistor 7 and the current collector 8, a voltage or a partial pressure corresponding to the deflection angle of the rod 3 can be output from the terminal 9. . Further, a magnet 10 is attached to the inner bottom surface of the case 1 so that the vehicle has an acceleration
When the weight 4 returns to the initial position after shifting to the state of FIG.
The damping vibration of the weight 4 is prevented by utilizing the attraction force. That is, when the vehicle decelerates, the weight 4 performs a pendulum motion from its initial position in the direction of arrow P in FIG. 1 (the direction toward the back of the paper in FIG. 2).
The pendulum moves in the direction of arrow Q (the front side in the drawing of FIG. 2). At this time, when the weight 4 approaches the initial position, the magnet 10
The weight 4 is quickly returned to the initial position without damping vibration, so that the acceleration of the vehicle can always be measured accurately. Therefore, when the vehicle is stopped or at a constant velocity, the weight 4 is in the initial position and the rod 3 is oriented vertically, and this state is stably maintained by the magnetic attraction of the magnet 10.

That is, in this acceleration sensor, when the vehicle decelerates, the slider 5 moves to the right from the position shown in FIG. 1 according to the acceleration, and when the vehicle accelerates, the slider 5 moves according to the acceleration. The slider 5 is moved to the left from the position shown in FIG. 1, and when the slider 5 moves in this manner, the relative position with respect to the resistor 7 changes. Can be converted to a voltage and measured. In this acceleration sensor, the slider 5 and the resistance board 6 constituting the detecting means can be regarded as variable resistors, and the sliding element which is a component on the actuator side of the detecting means is used. Since the slider 5 is provided at a position separated from the rotation center of the rod 3, the displacement of the slider 5 is large, and a large output can be obtained from the resistance substrate 6. Therefore, it is not necessary to amplify the output value from the resistance substrate 6 with an amplifier, and the cost increase can be largely suppressed as compared with the piezoelectric acceleration sensor. Moreover, since the slider 5 is provided between the rotation center of the rod 3 and the weight 4, the rod 3
Can be shortened, and the resistance substrate 6 can be arranged below the support shaft 2, so that the entire acceleration sensor can be reduced in size.

In the first embodiment, the weight 4 is made of Fe
Uses metallic materials. Further, if the binding of the magnet 10 is too strong, measurement can be performed only when the acceleration in the front-rear direction of the vehicle is large. It is preferable to set in advance so that the binding of the magnet 10 is released.

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

The acceleration sensor shown in FIGS.
And a pair of rods 3 and 13 supported by the support shaft 2 so as to be rotatable about the support shaft 2.
13, a pair of weights 4 and 14 respectively attached to one end of each of the rods 3, a pair of sliders 5 and 15 each attached to the other end of each of the rods 3 and 13, and each of the sliders 5 , 15 and a pair of resistance substrates 6, 16 arranged so as to face each other, and a pair of stoppers 11, 12 for restricting each rod 3, 13 from moving from its initial position in a specific direction. When the vehicle decelerates, the weight 4 makes a pendulum motion in the direction of arrow P in FIG. 4 (the direction toward the back of the paper in FIG. 3), and when the vehicle accelerates, the weight 6 moves in the direction of arrow Q in FIG. (The front side of the drawing). That is, the movement of the weight 4 from the initial position in the direction of the arrow Q is regulated by the stopper 11, and the movement of the weight 14 from the initial position in the direction of the arrow P is regulated by the stopper 12. Further, similarly to the case where the resistor 7 and the current collector 8 are formed concentrically on the surface of the one resistance substrate 6 facing the slider 5, the resistance 7 and the current collector 8 are in contact with the slider 15 of the other resistance substrate 16. Resistors and current collectors (not shown) are formed concentrically on the opposing surface, and when the sliders 5 and 15 are slid on the resistive substrates 6 and 16, respectively, the circuit resistance changes. It has become. That is, when the weight 4 changes position according to the acceleration at the time of deceleration of the vehicle, the resistance value corresponding to the deflection angle of the rod 3 is measured and output, and the weight 14 changes position according to the acceleration at the time of acceleration of the vehicle. Then, a resistance value corresponding to the deflection angle of the rod 13 is measured and output.

The acceleration sensor has weights 4, 14
Are provided at respective initial positions, so that when the vehicle shifts from the deceleration state to the stop state and the weight 4 moves toward its initial position, the weight 4 controls the stopper 11. Similarly, when the vehicle shifts from the accelerated state to the constant velocity state and the weight 14 moves to its initial position, the weight 14 is restricted by the stopper 12, so that no damped vibration is performed. In other words, the acceleration sensor detects the damping vibration of the weights 4 and 14 which is concerned when the vehicle shifts to the state of zero acceleration in the front-rear direction.
This is prevented by 1 and 12 to improve reliability. Also,
Since the sliders 5 and 15 are provided at positions separated from the rotation centers of the rods 3 and 13, a large output can be obtained from the resistance substrate 6, and the rods 3 and 13 are connected to the common support shaft 2. And the structure can be simplified.

FIG. 5 is an internal configuration diagram showing a third embodiment of the acceleration sensor according to the present invention, and FIG. 6 is an internal configuration diagram taken along the line BB of FIG. 5, corresponding to FIGS. The parts are denoted by the same reference numerals.

In the acceleration sensor shown in FIGS. 5 and 6, sliders 5 and 15 are mounted between rods 3 and weights 4 and 14 of rods 3 and 13 suspended on the rod 2, respectively. Substrate 6,
16 is disposed below the support shaft 2, and has a smaller height dimension than the second embodiment.

FIG. 7 is an internal configuration diagram showing a fourth embodiment of the acceleration sensor according to the present invention, and FIG. 8 is an internal configuration diagram viewed along line CC of FIG.

The acceleration sensor shown in FIGS. 7 and 8 is based on the principle of a slide operation type variable resistor, and is divided into a narrow portion and a wide portion within a case 17 by a step 18a. Guide rod 18, a guide rod 19 which is divided into a narrow portion and a wide portion with a step 19 a as a boundary, and a pair of weights 20 respectively inserted through the narrow portions of the guide rods 18 and 19. , 21 and a pair of sliders 22, 23 respectively attached to the bottom surfaces of the weights 20, 21,
Coil springs 24 and 25 for biasing weight 20 from both sides
And the coil springs 26, 2 for urging the weight 21 from both sides
7 and a resistor 2 for bringing the sliders 22 and 23 into sliding contact with each other.
8 and a resistor substrate 30 on which a current collector 29 is formed. As shown in FIG. 7, the initial positions of the weights 20 and 21 are set at positions where they come into contact with the step portions 18a and 19a by the urging forces of the coil springs 24 and 26, respectively. The movement of the guide rod 18 to the wide part is restricted, and similarly, the movement of the weight 21 from its initial position to the wide part of the guide rod 19 is restricted.

That is, when the vehicle decelerates (or accelerates)
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 vehicle.
The weight 21 slides along the narrow portion of the guide rod 19 according to the acceleration of the weights 20 and 21.
Slides, the relative position between the sliders 22 and 23 and the resistor 28 changes. As in the above-described embodiments,
The acceleration of the vehicle at the time of deceleration or acceleration can be converted into a voltage and measured. Further, when the vehicle shifts to the state of zero acceleration in the front-rear direction, the weights 20, 21 can quickly return to the respective initial positions subject to the regulation of the steps 18a, 19a, and these steps 18a, 19a Since the same functions as the stoppers 11 and 12 in the second and third embodiments are performed, a highly reliable acceleration sensor which does not have a fear of outputting an erroneous measurement value due to the damped vibration of the weight can be obtained. ing. Furthermore, since the weights 20 and 21 are acceleration sensors of the type that detect the acceleration by sliding, the thickness can be reduced as compared with the above-described first to third embodiments.

The acceleration sensor according to the present invention can measure the acceleration of the vehicle in the width direction instead of the front-rear direction.

As described above, in the acceleration sensor according to the present invention, when the position of the weight fluctuates according to the direction and magnitude of the acceleration generated by braking or running of the vehicle, the relative position of the weight and the fixed member is accordingly changed order to make the transition, the acceleration can be measured by detecting the amount of change in the relative position detecting means, moreover, since the undesired movement of the weight is suppressed by the magnet and the scan <br/> stopper stepped portion And stable output characteristics can be obtained.

[Brief description of the drawings]

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

FIG. 2 is an internal configuration diagram of FIG. 1 as viewed from the side.

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

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

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

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

FIG. 7 is an internal configuration diagram showing a fourth embodiment of the acceleration sensor according to the present invention.

FIG. 8 is an internal configuration diagram viewed along line CC of FIG. 7;

[Explanation of symbols]

 1,17 Case 2 Support shaft 3,13 Rod 4,14,20,21 Weight 5,15,22,23 Slider 6,16,30 Resistor board 7,28 Resistor 8,29 Current collector 10 Magnet 11 , 12 Stopper 18, 19 Guide rod 18a, 19a Step 24, 25, 26, 27 Coil spring

Claims (2)

(57) [Claims] 1. An acceleration sensor mounted on a vehicle for measuring the acceleration of the vehicle, a rod having a weight at one end and pendulum-moving according to the acceleration, and rotatably supporting the other end of the rod. A fixed member, a magnet provided on the fixed member for attracting the weight to a neutral position of the pendulum motion, and provided between the rotation center of the rod and the weight.
A displacement detecting means, and a said detection element provided on the fixed member so as to face the displacement detecting means, the relative position between the displacement detection means and said detection element is varied in accordance with the pendulum movement of the rod An acceleration sensor for detecting the displacement of the rod from the detection element. 2. An acceleration sensor attached to a vehicle and measuring the acceleration of the vehicle, a pair of weights slid in accordance with the acceleration, a fixing member slidably supporting these weights, and the weight and the fixing. A detecting means for detecting a relative position with respect to a member, and a stopper step provided on the fixing member, wherein the weights are regulated so as to slide in opposite directions with respect to the stopper step. Characteristic acceleration sensor.