JP3603104B2 - Vehicle stress measuring device - Google Patents

Description

[0001]
[Industrial applications]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle stress measuring device that measures stress such as shear strain generated on an axle or a structure near an axle of a transportation vehicle such as an automobile, an aircraft, and a railway vehicle.
[0002]
[Prior art]
Examples of measurement methods for measuring stress such as shear strain generated on an axle or a structure near an axle of a transportation vehicle such as a transportation vehicle such as an automobile, an aircraft, or a railway vehicle include a photoelasticity method, a stress paint film method, and a course. There are a tick method, a holography method, a strain gage method, and the like, and generally, the strain gage method is frequently used. Strain gauges are abundant and easy to handle, but they must be used as transducers for stress measurement, and the strain gauge method receives stress in all directions applied to the strain gauge, so analysis is necessary. It is necessary to attach the strain gauges to the axle or a structure near the axle to extract necessary stress.
[0003]
[Problems to be solved by the invention]
A conventional stress sensor composed of a strain gauge senses stress in all directions applied to the strain gauge, so that, for example, even if it is desired to measure a road surface frictional force, it can only measure stress including other crosstalk, or It is necessary to attach a plurality of stress sensors composed of strain gauges and measure unnecessary stress by the stress sensor to remove the stress. In view of the above, the present invention uses a stress sensor having a differential capacitor function configured by a semiconductor process or the like to transmit a stress transmitted from an X direction, a Y direction, a Z direction, or the like of an axle of a vehicle or a structure near the axle. On the other hand, by taking advantage of only capturing the stress in one direction and reducing or not knowing the other stresses, it is possible to accurately and easily measure the stress generated in the axle or a structure near the axle during rapid braking of the vehicle, It is an object of the present invention to provide a vehicle stress measuring device.
[0004]
[Means for Solving the Problems]
The present invention according to claim 1 is a stress measuring device for a vehicle, comprising a stress sensor attached to a vehicle axle or a structure near the axle and detecting a stress acting on the structure. The detection sensor includes a male electrode plate and a female electrode plate each having a plurality of comb blade electrodes arranged side by side in a protruding state on at least one surface of the substrate, and a comb blade electrode of the male electrode plate and a female electrode plate. Detecting the stress based on a change in distance between the comb electrode and the comb electrode, wherein the male electrode plate has a thickness set to be smaller than the thickness of the female electrode plate, and each of the comb blades of the male electrode plate electrode is characterized in that in mesh between the respective comb electrodes of Oite female electrode plates thickness direction center position of the female electrode plate. According to a second aspect of the present invention, a signal processing circuit such as an amplifier circuit connected to the male electrode plate and the female electrode plate is integrally formed on the substrate of the stress sensor. The present invention of claim 3, the stress sensor according to claim 1 and 2, is mounted to the stress measuring means comprising a hole provided in the structure of the vehicle axis or axle near the vehicle, axle or axles near The structure is such that the capacitance of the capacitor between the comb blade electrodes of the stress sensor is changed in accordance with the shear strain generated in the structure, and the amount of change is directly extracted as a stress signal. According to a fourth aspect of the present invention, a stress measuring means for measuring a vertical load and a stress measuring means for measuring a road surface frictional force are provided on an axle of the vehicle or a structure near the axle, and each of the stress measuring means is provided with a stress measuring means. A stress sensor was attached to each, and one of the stress sensors corresponded to the vertical load corresponding to the shear strain generated in the axle or the structure near the axle, and the other stress sensor corresponded to the shear strain generated in the axle or the structure near the axle. The road surface frictional force is directly detected, and both detection signals are processed to calculate the road surface friction coefficient.
[0005]
[Action]
According to the first aspect of the present invention, when a stress sensor having a differential capacitor function is attached to an axle of a vehicle or a structure near the axle, the structure can be applied to the axle or a structure near the axle during rapid braking of the vehicle. In accordance with the generated shear strain, the distance between the comb electrodes of the male and female electrode plates of the stress sensor changes only in one direction acting in the lamination direction of the electrode plates, that is, in one direction acting in the orthogonal direction, thereby changing the capacitance. Can be measured in only one direction corresponding to. According to a second aspect of the present invention, by integrally forming a signal processing circuit such as an amplifier circuit on the substrate of the stress sensor according to the first aspect, a change in capacitance can be directly extracted as a change in stress. it can. According to a third aspect of the present invention, a hole is formed in a vehicle axle or a structure near the axle to form a stress measuring means, and the stress sensor according to the first and second aspects is mounted on the stress measuring means. Thereby, the stress in only one direction can be measured more accurately. According to a fourth aspect of the present invention, a stress measurement unit including a hole for measuring a vertical load and a stress measurement unit including a hole for measuring a road surface frictional force are separately provided on an axle of a vehicle or a structure near the axle. By separately mounting the stress sensors according to claims 1 and 2 in the holes of the respective stress measuring means, and calculating the output signals of the two stress sensors, it is possible to obtain the road surface friction coefficient without crosstalk. .
[0006]
【Example】
What is shown here is an example of a preferred embodiment, and the claims are not limited to the examples shown here. Hereinafter, the present invention will be described based on an example of an illustrated example of a vehicle stress measuring device. FIG. 1 shows a basic configuration example of a stress sensor having a differential capacitor function. The stress sensor S includes a male electrode plate A and a female electrode plate B. The size of the male electrode plate A in the thickness direction is smaller than that of the female electrode plate B. The male electrode plate A and the female electrode plate B have a plurality of comb-shaped electrodes a1 to a4 and b1 to b6 projecting from the substrates a and b, respectively, and mesh with each other at intervals. The number of the comb-shaped electrodes of the male electrode plate A is one less than the number of the comb-shaped electrodes of the female electrode plate B, and the total number is desirably set to an even number. It is located at the center with respect to the thickness direction of the mold electrode plate B, and the comb electrode of the male electrode plate A is arranged at the center between the comb electrode of the female electrode plate B. The male electrode plate A and the female electrode plate B arranged as described above move when the stress is transmitted in the direction in which the electrode plates are stacked, and the comb blade electrodes a1 to a4 of the male electrode plate A The structure is such that the distance between the comb blade electrodes b1 to b5 of the pattern electrode plate B changes.
[0007]
The arrows shown in FIG. 2 indicate the shearing stress applied to the stress sensor S. At this time, both the comb blade electrodes of the male electrode plate A and the comb blade electrode of the female electrode plate B move. Move in the directions of the arrows, the distance between the two comb blade electrodes changes, and the capacitance between the two comb blade electrodes (conductors) changes. That is, when a stress that changes the distance between the comb electrode of the male electrode plate A and the comb electrode of the female electrode plate B acts, a voltage that is inversely proportional to the square of the stress (electrostatic attraction) can be measured. This electrostatic attraction is, of course, a shear stress. The shear stress is not applied to the differential capacitor C formed by the comb blade electrodes (a1 to a4, b1 to b5) of the stress sensor S from one direction, but is applied from the other direction. And the pressure applied in the twisting direction. The stress sensor S shown in FIG. 1 has two comb blade electrodes (a1 to a4, b1) when the male electrode plate B moves up or down with respect to the female electrode plate B for a vertically acting stress. The distance between ｂb5) does not change, and is the same as the state in which the electrostatic attraction does not work, and there is no voltage output. The same applies when the female electrode plate B moves with respect to the male electrode plate A. When a vertical stress acts on the entire stress sensor S, the comb blade electrodes of both the male electrode plate A and the female electrode plate B move in the same direction, and change like a mountain or valley. Even in this case, there is no voltage output because the distance between the respective comb blade electrodes does not change. In addition, with respect to the stress acting in the twisting direction, the male electrode plate A moves up and down with respect to the female electrode plate B and moves so as to change the distance between the comb blade electrodes. As a result of the electrostatic attraction, a voltage output is obtained. As described above, the stress sensor S always detects only the stress that acts in the laminating direction of the male electrode plate A and the female electrode plate B, that is, in the orthogonal direction.
[0008]
As shown in FIG. 3, the cross-sectional shape of the comb-shaped electrodes (a1 to a4) of the male electrode plate A is not a prism but a columnar shape, and the cross-sectional shape of the comb-shaped electrodes (b1 to b5) of the female electrode plate B is moderate. It is formed into two types, a convex type and a concave type, having a radius of curvature. The comb-shaped electrode of the female electrode plate is alternately combined with the convex type and the concave type. With the configuration arranged between the electrode and the concave comb electrode, the male electrode plate A changes upward or downward with respect to the female electrode plate B, and the distance between the comb electrode changes. 3, the distance between the comb blade electrodes changes in the relationship on the left side of FIG. 3, but the change in the distance between the comb blade electrodes changes little or no in the relationship on the right side. Therefore, by canceling or not outputting the output on the side where the distance between the comb blade electrodes changes, it is possible to create a stress sensor that can easily cope with such movement. A differential capacitor having such a comb-shaped electrode may be joined to a frame made of the same material as a group IV element or a steel material to form a stress sensor S, or the frame may be made of the same semiconductor as the differential capacitor. It is possible to make them simultaneously in the process.
[0009]
FIG. 4 shows that a differential capacitor C having comb-blade electrodes (a1 to a4) and (b1 to b5) is joined or laminated on a substrate (frame) f, and a part of the substrate f is connected to the comb-blade electrode. This is a stress sensor S in which a terminal block t for connecting wiring by aluminum evaporation or the like and a signal processing circuit e such as a temperature compensation circuit and an amplification circuit are integrally formed. Here, r indicates an insulating portion. FIG. 5 shows that a substrate (frame) f is formed separately from the comb-shaped electrodes, and they are bonded using a bonding technique to produce a stress sensor S. In this case, alignment of the male and female comb-shaped electrodes is performed. It is necessary to join while watching carefully. FIG. 6 shows a stress sensor S manufactured by a semiconductor process, in which a substrate (frame) f is not bonded later, but comb blade electrodes (a1 to a4) and (b1 to b5) are formed. At the same time, a substrate (frame) f is also made. This stress sensor S differs from the above-described one in that a substrate f has a bottom plate. If the stress transmission ability is significantly reduced, the bottom plate may be removed by a process such as etching. According to the semiconductor process, there is an advantage that an accurate and small stress sensor can be manufactured.
[0010]
FIG. 7 shows a vehicle stress measuring device in which a stress sensor S is attached to an axle of a vehicle or a structure K near the axle. The stress sensor S is mounted in a hole which is a stress measuring means g. The hole is provided in the axle or a structure K near the axle. The stress measuring means g analyzes the stress distribution and attaches the peripheral wall of the hole through which the shear stress generated when a sudden braking force is applied as shown in FIG. It is desirable that the position of the stress measuring means g opened in the strut be provided at an optimum position in stress distribution analysis such as FEM analysis. It should be noted that there are places where stress is not transmitted, at which point the stress sensor cannot detect shear strain. However, even if a stress sensor is installed in a place where other stresses are transmitted, those stresses are not detected, so that there is no need to consider them.
[0011]
The stress measuring means g is formed in the same direction as the traveling direction of the vehicle. This is for detecting the frictional force generated with respect to the sudden braking force of the vehicle. Further, in order to obtain the road surface friction coefficient μ, it is necessary to measure the vertical load N and the road surface friction force F. However, the stress measuring means for obtaining the vertical load N is different from the position shown in FIG. Have. The same stress sensor S used for measuring the road surface friction force F can be used as the stress sensor S attached to the stress measuring means g. The stress measuring means g for measuring the vertical load N provides a hole in the axle or a structure K near the axle similarly to the road surface friction force F. Further, the position of the stress sensor S may be the same as the position of the stress sensor S for measuring the road surface friction force F, or may be separately installed at a position where stress analysis is performed and the road surface friction force F and the vertical load N are measured. Stress sensors are arranged so as to be orthogonal to each other. The hole and the stress sensor, which are the stress measuring means, are joined by a joining method such as use of various adhesives, diffusion joining, electron beam welding, or laser welding. These are methods that can transmit the shear stress transmitted through the hole as the stress measuring means to the stress sensor. There are three types of joints between the hole and the stress sensor S in which the inner surface of the hole is in contact with the frame, the inner surface of the hole is in contact with the frame and the electrode plate, and the inner surface of the hole is in contact with the electrode, and any method may be used. In addition, heat resistance glass or the like may be anodic-bonded to the inner surface of the hole in consideration of the strength of the stress sensor bonding portion. After joining the hole as the stress measuring means and the stress sensor, there is a gap between the two. The gap may be filled with a material that does not transmit stress, such as resin. After joining the hole as the stress measuring means and the stress sensor, it is desired to close the hole in consideration of waterproofness.
[0012]
【effect】
According to the present invention, it is possible to measure a load / stress in only one direction purely for a load / stress applied to a stress sensor having a differential capacitor function in all directions, and the load / stress in the direction to be measured is Since measurement can be performed by installing a stress sensor in that direction, stress sensors are installed at multiple points to eliminate the load and stress of crosstalk, as in a conventional stress sensor consisting of a strain gauge. It does not require a complicated device that calculates the load and stress of the vehicle, the stress measurement device is simple and compact, and the load and stress in only one direction can be measured with a single stress sensor. Can be attached. Further, since the stress measuring means for attaching the stress sensor is formed by a hole without having a particularly complicated structure, the stress sensor can be easily attached to the structure of the vehicle without requiring any special technical force for attaching the stress sensor. Since the load / stress in only one direction can be measured purely, the road surface frictional force F and the vertical load N can be measured by two stress sensors, and the road surface friction coefficient μ can be easily taken out.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a basic structure of a stress sensor.
FIG. 2 is an operation explanatory view of a comb blade electrode of the stress sensor shown in FIG. 1;
FIG. 3 is a sectional view showing a modification of the comb blade electrode of the stress sensor.
FIG. 4 is a plan view showing another embodiment of the stress sensor.
FIG. 5 is a perspective view showing another embodiment of the stress sensor.
FIG. 6 is a perspective view showing still another embodiment of the stress sensor.
FIG. 7 is a perspective view showing an embodiment of the stress measuring device.
FIG. 8 is an enlarged perspective view of a stress measuring unit shown in FIG. 7;
[Explanation of symbols]
S Stress sensor A Male electrode plate B Female electrode plate a, b, f Substrate (frame)
a1 to a4, b1 to b5 Comb blade electrode C Differential capacitor K Structure g Stress measuring means

Claims (4)

A vehicle stress measurement device having a stress sensor attached to an axle or a structure near the axle of a vehicle and detecting a stress applied to the structure,
The stress detection sensor includes a male electrode plate and a female electrode plate each having a plurality of comb-shaped electrodes arranged side by side in a protruding state on at least one surface of the substrate,
Detecting the stress based on a change in the distance between the comb blade electrode of the male electrode plate and the comb blade electrode of the female electrode plate,
The male electrode plate, the thickness is set smaller than the thickness of the female electrode plate, and each comb electrode of the male electrode plates, each comb Oite female electrode plates Thickness direction center position of the female electrode plate A vehicle stress measuring device, which is engaged between blade electrodes . The stress measuring device for a vehicle according to claim 1, wherein a signal processing circuit such as an amplifier circuit connected to the male electrode plate and the female electrode plate is integrally formed on the substrate of the stress sensor. The stress sensor according to claim 1 or 2, wherein the stress sensor is mounted on a stress measuring means comprising a hole provided in an axle or a structure near the axle of the vehicle, and a stress corresponding to a shear strain generated in the axle or a structure near the axle. varying the capacitance between the comb electrodes of the sensor, the stress measuring device of the vehicle, characterized in that had Unishi I to extraction directly the change amount as a stress signal. A structure near the axle or wheels of the vehicle is provided with a stress measuring means for measuring a vertical load and a stress measuring means for measuring a road surface frictional force. The stress sensor directly detects the vertical load corresponding to the shear strain generated on the axle or the structure near the axle, and the other stress sensor directly detects the road surface frictional force corresponding to the shear strain generated on the axle or the structure near the axle. 4. The stress measuring device for a vehicle according to claim 1, wherein the detection signal is arithmetically processed to extract a road surface friction coefficient.

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