JPH05297018A - Detection device with automatic diagnotic function - Google Patents

Abstract

PURPOSE:To confirm operation of a detection device and an entire system operating a self-diagnostic function at any moment since an assumed acceleration of 50-100G on collision does not occur during normal operation in an acceleration detection device for air bag of a vehicle. CONSTITUTION:The change in piezo resistance is taken out as an output by changing a weight part 4 of a silicon plate 1 by a needle 7 which is laid out in an outer case 5 and then self diagnosis is made by a control circuit. By adding a self-diagnosis function to an acceleration-detection device for air bag for vehicle, self diagnosis can be made without operating the main air bag at an arbitrary time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving body such as an automobile, and more particularly to a suitable acceleration sensor (switch) used in an air bag system for protecting an occupant in the event of a collision. The present invention relates to a configuration related to the method and a method thereof.

[0002]

2. Description of the Related Art Japanese Patent Application No. Sho 62-309684 (Dec. 9, 1987)
As described above, the purpose of the semiconductor capacitive acceleration sensor is to detect acceleration of about 1 to 2 G, which is used for suspensions even in automobiles, and it always operates as a sensor according to the operation of the suspension. is there. These are not only semiconductor capacitive acceleration sensors,
The same applies to the semiconductor piezoresistive acceleration sensor sold by IC Sensors, as long as the detected acceleration is about 1 to 2G.

However, as shown in the above-mentioned industrial application fields, when it is used in an air bag system for automobiles, the detected acceleration is about 50 to 100 G, and it can be detected if it is not a collision. There is no acceleration. These are switches rather than sensors, and they are regenerated each time because the system is broken by the collision.

The detected acceleration of 50 to 100 G cannot be detected unless it is a collision, and it is not possible to always detect and confirm the operation by 1 to 2 G like the suspension. Therefore, it is feared that if there is no accident such as a collision when you purchase a car and ride it for several years, the acceleration switch will work even after several years. As a similar patent, Japanese Patent Application
In the case of the detection device with self-calibration function of 1-271666 (October 20, 1991), if there are changes in the characteristic values at the beginning of use, the values are calibrated to the values as good as new. However, unlike the present invention, the operation corresponding to 50 to 100 G is not caused to perform the original function check and the system operation check.

What is different from the prior art is that any acceleration sensor (switch) is used like an air bag system to cause an operation equivalent to 50 to 100 G which does not occur only at the time of a collision to cause a sensor (switch) or system. It relates to a displacement detection device that has a self-diagnosis function by confirming the operation. By forcibly changing the weight part during recognition, the operation can be confirmed at any time in case of an emergency (collision). Is made easy.

[0006]

As described in the above-mentioned prior art, no matter what sensor (switch) is used, unlike the acceleration of 1 to 2 G of the suspension or the like, 50 to 100 G when the air bag is started is a normal drive. Since it does not appear under the conditions, it is possible to confirm the operation of the sensor (switch) or system by forcibly operating it, so the issue is how to forcibly confirm the operation. come.

As in the present invention, it is conceivable to use a stopper of a weight as a driving needle, control as a subsystem by a microcomputer, or operate by external communication means. Is sure to work.

Further, in order to confirm the system, the main air bag is not operated and the lamp is turned on,
You can check the whole by operating the mini air bag.

[0009]

Means for Solving the Problems 1 to 1 for suspension
Unlike 2G, 50-100G airbags are so large that the weight of the weight detecting acceleration is not comparable to the weight, so the needle (stopper) to be forcibly operated is also mounted. Since other means that is easy to assemble can be performed by means such as utilizing an in-vehicle microcomputer of an automobile, it is possible to deal with it.

[0010]

[Function] Semiconductor piezoresistive acceleration sensor (switch)
[Or the same applies to the semiconductor capacitance type] 50 to 100G
The acceleration of does not occur unless a collision occurs. Therefore, by moving the needle directly mounted on the outer case with an actuator, the weight of the Si portion of the needle is changed to change the piezo resistance (change corresponding to 50 to 100 G) arranged on the beam portion of the system. By operating the lamp (lighting the lamp or operating the mini air bag)
The operation is confirmed instead of the acceleration of 100 G.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 2 shows a block diagram of the control system of FIG. 1, FIG. 3 shows a block diagram showing an example of control by the microcomputer, and FIG. 3 shows a capacitive formula instead of the piezoresistive formula of FIG. It is 4.

FIG. 1 is a cross-sectional view of the present invention, in which a glass plate 2 is joined to a silicon plate 1, a piezoresistive portion 3 is arranged on a beam portion processed on the silicon plate 1, and at the tip thereof. The weight portion 4 that changes according to the acceleration is provided, and the piezoresistive portion 3 of the beam portion changes due to the movement thereof to detect a value corresponding to the acceleration. These are adhered and fixed to the outer case 5 together with the glass table 2 at the adhesive portion 6. A load needle 7 that also serves as a stopper and for self-diagnosis is installed on the outer case 5 with a holder 8. air·
The acceleration detection for the back is planned to be 50 to 100 G at the time of a collision, and is not detected during the normal operation of the vehicle.
The set weight 4 hardly moves, and the piezoresistor 3 cannot detect a resistance change enough to trigger the system. Therefore, in the present invention, the load needle 7 is moved to bring the stopper point 7'of the tip into contact with the weight portion 4 so that the piezoresistive portion 3 causes a resistance change enough to trigger the system and is taken out from the terminal lead-out portion 9 as a symbol. It is a thing. As a result, it is possible to detect a change corresponding to a collision at the time of approval and self-diagnose the detection unit and the entire system.

FIG. 2 is a block diagram showing the control system of the present invention. The control unit 10 receives a signal and controls the needle 7, and the actuator 11 also controls the needle 7, and the switching unit 12 performs feedback control to the control unit 10. As a result, the load drive 13 causes the lamp to light up and the mini air to flow.・ Self-diagnosis is performed by performing operations such as backing. This enables self-diagnosis of the detection unit and the entire system without operating the main air bag.

FIG. 3 is a similar control system block diagram, but shows an example in which a part or the whole of the control unit 10 is controlled by the microcomputer 14. Similarly, these control systems are controlled by an external communication system 15. It goes without saying that the instructions can be controlled from the outside.

FIG. 4 shows an example of the present invention for a capacitive type sensor instead of the piezoresistive type detecting section shown in FIG. Similar to FIG. 1, these are obtained by processing a silicon plate 1'and providing a gap 16 for capacitance detection provided between a weight portion 4'and an upper glass plate 17, and the other whole structure is shown in FIG. Is similar to. That is, the glass plate 2'is joined to the silicon plate 1 ', the upper glass plate 17 is disposed on the upper part, and they are fixed to the outer case 5'by the adhesive portion 6, and the change of the gap 16 is changed to the electrode including the through hole. 18
It is an example of a capacitive detection device that the signal is extracted from the silicon plate 1'and the silicon plate 1'through the terminal lead-out portion 9'to the control unit 10 side. In the present invention, the holder 8'is provided on the outer case 5 '. By forcibly changing the weight 4'of the silicon plate 1'by the needle 7 ",
As in the case of FIG. 1, by changing the capacitance detection gap 16 and changing the trigger value of the system, a capacitance type detection device for performing self-diagnosis by operating the lamp of the load or operating the mini air bag is shown. Is.

In the driving method of the needle 7 in FIG. 1, F indicates the operation, and specifically, the stroke of the needle is determined and a load is applied by externally turning on and off by a solenoid valve. Needless to say, the operation of the needle 7 moves up and down smoothly, and the weight 4 is moved by introducing air through a hole in the needle 7.

[0017]

According to the present invention, by providing a self-diagnosis unit in an acceleration detecting device for an automobile airbag, a self-diagnosis system can be used at the discretion even if the expected 50 to 100 G is not reached at the time of a collision. It is possible to confirm the detection unit and the entire system by operating.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a piezoresistance type acceleration detection device with a self-diagnosis function according to the present invention.

FIG. 2 is a diagram showing a control block diagram of an acceleration detection device including the self-diagnosis function.

FIG. 3 is a diagram showing a block diagram of the control of FIG. 2 according to a communication instruction from a microcomputer or the outside.

FIG. 4 is a sectional view of a capacitive type self-diagnosis function added speed detection device instead of the piezoresistive type of FIG.

[Explanation of symbols]

1, 1 '... Silicon plate, 2, 2' ... Glass base, 3 ... Piezoresistive part of silicon part, 4, 4 '... Weight part of silicon part, 5, 5' ... Outer case, 6 ... Pedestal in case Adhesive part for adhering 7 ... Stopper / load needle for self-diagnosis, 7 '... Tip stopper point, 7 "... Self-diagnosis needle, 8, 8'Needle holder, 9, 9' ... Terminal lead-out Parts, 10 ... Control unit, 11 ... Actuator, 12 ... Switching unit, 13 ... Load drive unit, 14 ... Microcomputer, 15 ... External communication means, 16 ... Gap for capacitance detection, 17 ... Upper glass plate,
18 ... Electrodes including through holes.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masanori Kubota 2477 Kashima Yatsu Kashima, Katsuta City, Ibaraki Prefecture 3 Hitachi Automotive Engineering Co., Ltd.

Claims (8)

[Claims] 1. An apparatus for detecting a physical quantity as an electric quantity, comprising a detecting means, a means for self-diagnosing the same, and a signal processing means, the self-diagnosing signal being emitted from the self-diagnosing means and passing through a switching circuit. It was provided to the detection means, the detection means forcibly measures the driving state of the load, and the change can be operated by the sub-driving section other than the main driving section to confirm that the detection function is good. A detection device with a self-diagnosis function. 2. A data processing method for an apparatus for detecting a physical quantity as an electric quantity, comprising: issuing from a self-diagnosis means, applying a self-diagnosis signal to the detection means through a switching circuit, and measuring a response signal of the detection means to perform self-diagnosis. A data processing method which is characterized in that it is not necessary to perform a process and compare it with a previously measured diagnostic characteristic to confirm its operation. 3. A detection device system, which receives a command from a communication device or a microcomputer and performs the self-diagnosis according to claim 2. 4. The detection device system according to claim 2, wherein the self-diagnosis result is displayed on a display means provided in the processing device or the communication device and the microcomputer, and is stored in the storage means. .. 5. The detection device according to claim 1, wherein the detection means, the self-diagnosis means, and the processing means are formed on a silicon substrate. 6. The detection device according to claim 5, wherein the detection means and the self-diagnosis means are formed integrally with or in close proximity to the silicon single crystal substrate, and the stopper portion of the weight portion formed on the substrate moves up and down. Accordingly, the detection device is characterized in that it is forcibly displaced. 7. The detection device according to claim 1, wherein the detection means comprises a strain-generating body formed with a piezoresistive element, and a needle is attached to a weight portion formed in the central portion of the strain-generating body as a self-diagnosis means. 2. A detection apparatus, characterized in that the resistance of the piezoresistive element is changed by the vertical movement of the piezoresistive element, air pressure, or the like, and the resistance is measured and self-diagnosis is performed based on this change. 8. The detection device according to claim 1, wherein the detection means is a variable electrostatic capacitance composed of a movable electrode and a fixed electrode supported thereon, and the movable electrode and another fixed electrode as self-diagnosis means. A detecting device characterized in that the movable electrode is forcibly changed by a needle or the like in the gap formed by and the capacitance of the variable capacitance is measured, and self-diagnosis is performed based on this change.