JPH0587828A - Acceleration sensor - Google Patents

Abstract

PURPOSE:To simplify structure, improve assembly performance and facilitate adjustment. CONSTITUTION:A ball 4 which moves along the inner surface when acceleration is applied is accommodated in a body 2 on which a recessed part 3 having the inner surface having an ascent slope towards the periphery from the center is formed. Further, a detecting lever 5 whose one edge is pivotally installed on the body and the intermediate part contacts the top part of the ball 4 is installed. A noncontact type sensor 6 such as magnetic resistance sensor and photosensor are arranged, positioned at the other edge of the detecting lever. When accelerating speed is applied, the ball moves along the inner surface of the recessed part, and the position of the ball changes upwardly. At this time, the detection lever in contact with the ball is pushed upward, and the displacement of the other edge of the detecting lever is sensed by the noncontact type sensor, and an electric signal is taken out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration sensor capable of detecting directional information and level information of acceleration.

[0002]

2. Description of the Related Art One-way acceleration sensors using a strain gauge, a semiconductor gauge, a capacitance sensor, and a piezoelectric element are known. A three-dimensional (omnidirectional) acceleration sensor is a combination of one-direction acceleration sensors in three directions, or four strain gauges are arranged on a silicon wafer, and the output of each strain gauge is calculated to determine the direction of acceleration. A method for calculating a scalar amount has been proposed.

[0003]

However, since the conventional omnidirectional acceleration sensor has a complicated structure and is poor in assembling, the cost is high and the shape is large.
If the acceleration direction and the magnitude of acceleration are required,
There is a problem that a processing circuit for calculating and obtaining the output from each acceleration sensor in three directions is required, and further, if there are variations in the characteristics of each gauge in the case of four strain gauges, it is necessary to correct each. There is. The purpose of the present invention is to
An object of the present invention is to provide an acceleration sensor which has a simple structure, is easy to assemble, and is easy to adjust.

[0004]

In order to achieve the above object, the acceleration sensor of the present invention has a body formed with a concave portion having an inner surface having an upward slope from the center to the periphery, and the acceleration sensor accommodated in the concave portion. A ball that moves along the inner surface when a ball is applied, one end of which is pivotally attached to the body, an intermediate portion of which is in contact with the top of the ball, and which is displaced upward by the movement of the ball; And a non-contact type sensor that outputs an electric signal in response to the displacement of the other end of the detection lever.

[0005]

When the acceleration is applied, the ball moves along the inner surface of the recess, so that the position of the ball changes upward. At this time, the detection lever that is in contact with the ball is pushed up,
The displacement of the other end of the detection lever is detected by a non-contact type sensor including a magnetoresistive sensor and a photo sensor, and an electric signal corresponding to the magnitude of acceleration is extracted. By using the non-contact type sensor, acceleration can be detected without the acceleration directly detected by the sensing device being applied as stress.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of the acceleration sensor of the present invention. In the figure, an acceleration sensor 1 accommodates a ball 4 in a recess 3 formed in a body 2 and displaces a detection lever 5 upward by the movement of the ball 4 in accordance with the magnitude of acceleration. Is configured to detect the amount of displacement of the detection lever 5 by the change in magnetic force of the magnet 7, extract this as an electric signal by magnetoelectric conversion, process it in the sensor circuit 10, and output it from the output terminal 8 to an external circuit.

On the upper side of the body 2, there is formed a concave portion 3 which has a hemispherical surface or an inverted conical inclined surface having an upward gradient from the center to the periphery. Is housed. A support portion 9 is erected on one side of the body 2, and one end of a detection lever 5 is pivotally attached to the support portion 9 and the detection lever 5 is supported so as to be movable in the vertical direction. The detection lever 5 is held in contact with the top of the ball 4 housed in the recess 3 of the body by its own weight. The tip of the detection lever is L
A magnet mounting portion 5a bent in a letter shape is provided, and a magnet 6 is mounted on the front surface of the magnet mounting portion 5a. A sensor mounting portion 11 is provided on the other side of the one body, and the magnetoresistive sensor 6 is disposed on the sensor mounting portion 11 so as to face the magnet 6 of the detection lever.

FIG. 2 shows a circuit configuration of an acceleration sensor using a magnetoresistive sensor. The sensor circuit 10 is incorporated in the body 2 and is configured to operate with a power supply voltage + V supplied from the outside. Circuit 10
Is composed of four magnetoresistive elements 12a whose electric resistance values change depending on the strength of magnetism in the bridge circuit 12, which amplifies the bridge output by the differential amplifier 13 and outputs the sensor signal from the output terminal 8. Therefore, the amount of displacement of the detection lever 5 differs depending on the magnitude of the acceleration, so that the magnetic field strength received by the magnetoresistive element also differs, and the resistance value changes.

According to this embodiment, the magnitude of displacement of the detection lever changes according to the magnitude of acceleration, so that the resistance value of the magnetoresistive element changes according to the movement of the magnet according to the displacement amount of the detection lever. Then, this is taken out as an electric signal. FIG. 3 shows a configuration of an acceleration sensor using a photo sensor. The same members as those in the above embodiment are designated by the same reference numerals and the description thereof will be omitted. The acceleration sensor of this embodiment is characterized in that the displacement corresponding to the acceleration of the detection lever 5 is extracted as an electric signal by photoelectric conversion.

The tip of the detection lever 5 is bent into an L-shape, and a light transmitting portion 14 is formed at this bent portion 5b. When detecting the presence or absence of light (digital), the shape of the light transmitting portion 14 is formed in a rectangular window 14a having a narrow opening width as shown in FIG. 3B, and the amount of light (analog) is used.
Is detected, it is formed in the triangular window 14b shown in FIG. 3C. The body on which the tip of the detection lever 5 is located is provided with a sensor mounting portion 15 for disposing a photo sensor. The sensor mounting portion 15 faces the light transmitting portion 14 of the detection lever. A photosensor 18 including a light emitting diode 16 and a phototransistor 17, which are installed with the light transmitting portion interposed therebetween, is provided. As shown in FIG. 4, a member 19 having a slit 19a is arranged in front of the light emitting diode 16, and the light emitted from the light emitting diode 16 through the slit 19a is converted into a beam having a predetermined width and is received by the phototransistor 17. Let

FIG. 5 shows a circuit configuration of an acceleration sensor using a photo sensor. In addition, in this circuit 20,
The rectangular light-transmitting portion 13a shown in FIG. 3B is used, and is configured to obtain a sensor output of a digital signal.
In the sensor circuit 20, a light emitting diode 16 and a phototransistor 17 are connected in parallel between a power source + V and GND. The collector voltage of the phototransistor 17 is applied to one terminal of a comparator 21 and the reference voltage is applied to the other terminal. The sensor signal is input from the comparator 21 when this collector voltage becomes lower than the reference voltage.

Next, the operation of the sensor circuit will be described. When acceleration is not applied, the detection lever is in the position indicated by the solid line, so that the light from the light emitting diode cannot reach the phototransistor because it is blocked by the bent portion of the detection lever, which is not the light transmitting portion. In this state, the phototransistor is non-conductive, and the collector voltage becomes the power supply voltage V. Therefore, since the collector voltage is higher than the reference voltage, the comparator outputs a sensor signal when acceleration is not applied, for example, a LOW signal. When acceleration is applied, the ball moves along the inner surface of the recess and displaces the detection lever in the direction of the broken line. In the process of displacing the detection lever to the position of the broken line, the phototransistor is made conductive by receiving the light passing through the light transmitting portion. Then, since the collector voltage drops below the reference voltage, the comparator outputs a sensor signal when acceleration is applied, for example, a HIGH signal. According to the present embodiment, it is possible to determine whether or not the acceleration of a certain value or more is applied by the sensor output from the comparator. In the case of the triangular transparent portion 14b shown in FIG. 3C, the amount of displacement of the detection lever 5 according to the magnitude of acceleration can be detected as a continuous change in the amount of light. In the circuit configuration in this case, as shown in FIG.
The comparison voltage is not detected by, but directly amplified by the amplifier and output.

[0013]

As described above, according to the present invention, the detection lever is displaced by the movement of the ball when acceleration is applied, and this displacement is detected by the non-contact type sensor and converted into an electric signal. Since it is configured, the structure is simple, the assemblability is good, the adjustment is easy, the number of parts is small, and the size can be reduced. By using the non-contact type sensor, acceleration that is directly detected by the sensing device is not applied as stress, and high fracture strength can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an acceleration sensor using a magnetoresistive sensor of the present invention.

FIG. 2 is a circuit diagram of an acceleration sensor using a magnetoresistive sensor.

3A and 3B show a configuration of an acceleration sensor using a photosensor of the present invention, FIG. 3A is a cross-sectional view, FIG. 3B is a perspective view showing a shape of a light transmitting portion, and FIG. 3C is a shape of another light transmitting portion. It is a perspective view.

FIG. 4 is a configuration diagram of a light emitting unit side when performing analog measurement.

FIG. 5 is a circuit diagram of an acceleration sensor using a photo sensor.

[Explanation of symbols]

1 acceleration sensor, 2 body, 3 concave portion, 4 ball, 5 detection lever, 6 magnetic resistance sensor, 7 magnet, 10 and 20 sensor circuit, 14 light transmitting portion, 16 light emitting diode, 17 phototransistor, 18 photosensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanichi Tanaka No. 1 Noda, Toyota, Oguchi-cho, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd.

Claims (1)

[Claims] 1. A body having a concave portion having an inner surface with an upward slope from the center toward the periphery, and a body accommodated in the concave portion,
A ball that moves along the inner surface when acceleration is applied, and a detection lever that has one end pivotally attached to the body, an intermediate portion abuts on the top of the ball, and is displaced upward by the movement of the ball. And a non-contact sensor that outputs an electric signal in response to the displacement of the other end of the detection lever.