JPH11118825A - Capacitance type angular acceleration detector - Google Patents

Abstract

[PROBLEMS] To provide an angular acceleration detecting device capable of detecting an angular acceleration with high accuracy by suppressing the influence of a disc mounting error and a slit manufacturing error. The angular acceleration detecting device includes a spring portion in accordance with an angular acceleration generated when a rotating shaft rotates while an AC voltage is applied between a pair of annular electrode plates. Second disk 10
The third second blade portion 109 is relatively displaced in the circumferential direction with respect to the first blade portion 105 of the first disk 102, so that the overlapping area of the two blade portions 105, 109 changes. Since the first and second blade portions 105 and 109 face each other at a fixed interval with the pair of annular electrode plates 111 and 112 interposed therebetween, the first and second blade portions 105 and
9 by detecting the capacitance of the variable capacitor formed by the first and second blade portions 10.
It is possible to obtain the relative displacement amounts of 5, 109, and from this result, it is possible to calculate the angular acceleration occurring on the rotating shaft 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a first disk and a second disk which are fixed so as to rotate integrally with a rotating shaft and face each other, wherein the first disk is a rigid body. A second disk is provided with a first group of slits arranged in the circumferential direction, and the second disk acts on the disk with a slit forming portion formed with the second group of slits arranged in the circumferential direction. A spring portion that elastically displaces in a circumferential direction in accordance with the angular acceleration.
The present invention relates to an angular acceleration detecting device capable of detecting an angular acceleration generated on a rotation axis based on a relative displacement between a slit group and a second slit group.

More specifically, based on a change in capacitance between the first and second disks, detection of angular acceleration which is not affected by errors caused by assembling errors, manufacturing errors, etc. of these disks. The present invention relates to an angular acceleration detection device capable of performing the following.

[0003]

2. Description of the Related Art Conventionally, a liquid rotor type angular accelerometer and an eddy current type angular accelerometer are known as angular acceleration detecting devices for detecting angular acceleration of a rotating shaft.

The liquid rotor type angular accelerometer detects the movement of the liquid instead of the pendulum of the servo type accelerometer, and measures the angular acceleration from a feedback current when the movement of the liquid is balanced by a servo mechanism. . On the other hand, an angular accelerometer using an eddy current forms a magnetic circuit using permanent magnets, and a cylindrical aluminum rotor is arranged in the circuit, and is generated according to a change in the rotation speed of the rotor. It detects angular acceleration based on magnetic electromotive force.

However, the liquid rotor type angular accelerometer has a problem in that the rotation angle is limited, and the angular acceleration over an infinite rotation angle cannot be detected. Further, an angular accelerometer using an eddy current requires a high-sensitivity signal processing circuit because an obtained detection signal is weak.

In view of this, the present applicant has proposed, in International Publication No. WO93 / 20451, an angular acceleration detecting device capable of detecting the angular acceleration of the rotating shaft over an infinite angle range with a simple configuration. . This angular acceleration detection device
A first disk and a second disk that are fixed to rotate integrally with the rotation axis and face each other;
A first disk provided with a first slit group which is rigid and arranged in a circumferential direction; a second disk formed by a slit forming portion in which a second slit group arranged in a circumferential direction is formed; A spring portion for elastically displacing the formed portion in the circumferential direction in accordance with the angular acceleration acting on the disk, and an angular acceleration generated on the rotating shaft based on a relative displacement between the first slit group and the second slit group. Is detectable.

That is, as shown in FIG. 1, an angular acceleration detecting device 10 has a thin cylindrical housing 11, and a rotating shaft 13 to be measured is rotatable at the center of the housing 11 via a bearing 12. Penetrates through. A first disk 14 and a second disk 15 are fixed to the outer periphery of the rotating shaft 13 located inside the housing 11 in a state where the first disk 14 and the second disk 15 face each other. A first group of slits 16 and a second group of slits 17 are formed on the outer peripheral side of these disks 14 and 15 at a constant angular interval in the circumferential direction. The first and second slit groups 16 and 17 are opposed to each other, and the optical sensor 19 is arranged so as to sandwich them. The detection unit of the optical sensor 19 includes a light emitting diode 20 and a semiconductor position detector 21.

FIG. 2 shows the shape of the second disk 15 described above. As shown in this drawing, the second disk 15 has a slit-forming portion 1 whose outermost peripheral portion has an annular shape.
5a, where the second slit group 17 is formed. Inside the slit forming portion 15a, there is formed a spring portion 15b including three leaf springs 15c extending toward the center at intervals of 120 degrees from the inner peripheral surface thereof.
The inner ends of these three leaf springs 15c are continuous with the outer periphery of a shaft fixing portion 15d fixed to the outer periphery of the rotating shaft 13. Each of the three leaf springs 15c elastically deforms in the circumferential direction according to the angular acceleration acting on the slit forming portion 15a.

Next, the first and second disks 14, 1
5, first and second slit groups 16 formed in
17 will be described. The first slit group 16 formed in the slit forming portion 14a of the first disk 14
It consists of radially extending slits formed at regular angular intervals. On the other hand, the second disk 1
The second slit group 17 formed in the 5 slit forming portions 15a is constituted by slits extending at a certain angle with respect to the radial direction at the same angular interval but at a constant angle.

FIG. 3 shows the first and second groups of slits 16 and 17 developed in a linear direction from the circumferential direction. In this figure, a group of slits indicated by a dotted line is a first group of slits 1 formed on the first disk 14.
6 and those indicated by solid lines are second slit groups 17 formed on the second disk 15. The area surrounded by the imaginary line is the irradiation area of the parallel light from the light emitting diode 20. The slit group 16 is composed of slits 16a formed at a constant pitch p, and the other slit group 17 is
It is composed of a slit 17a inclined by a certain angle with respect to the slit 16a. These slits 16a
The intersection A between the light-receiving portion 17a and the light-receiving portion 17a defines a light passing portion. When both slits 16a and 17a relatively move in the horizontal direction, the intersection A moves in the vertical direction (that is, in the disk radial direction). This moving position is detected on the semiconductor position detector 21 side.

FIG. 4 shows an optical sensor 19 of the angular acceleration detecting device 10 and a signal processing circuit configuration of a sensor output signal. When the parallel light from the light emitting diode 20 passes through the intersection of the slits 16a and 17a and irradiates the detection surface 21a of the semiconductor position detector 21, the photocurrent outputs i1 and i2 distributed at a ratio corresponding to the irradiation position. Is output from the detector 21. The light amount of the light emitting diode 20 is controlled so that the sum of the outputs i1 and i2 is constant. Therefore, the movement position of the intersection A can be measured from the detection output of the detector 21, for example, one of the detection signals S.

When the rotating shaft 13 starts rotating or the rotation speed changes, the second slit group 17 on the second disk 15 side is moved to the first slit group on the other first disk 14 side. It is shifted in the circumferential direction with respect to the slit group 16. That is, the slit forming portion 15 on the side of the second disk 15
Since the spring portion 15b is elastically deformed in the circumferential direction by the inertia force a, the second slit group 17 is also shifted in the circumferential direction accordingly. As a result, the first slit group 16
Intersection A formed between the first slit group 17 and the second slit group 17
The (light transmitting portion) is shifted in the radial direction. For this reason, the light receiving position on the side of the semiconductor position detector 21 moves.
With this movement, the output S of the detector 21 changes.
Therefore, the angular acceleration generated on the rotating shaft 13 can be measured from the detector output S.

[0013]

In the angular acceleration detecting device of this construction, the amount of movement in the radial direction of the intersection formed between the first slit group 16 and the second slit group 17 is detected. ing. As described above, the detection target is the intersection (light transmitting portion) close to the point. For this reason, surface runout due to an assembling error of each disk during device manufacturing,
The position of the intersection to be detected fluctuates due to center runout and manufacturing errors of each slit group. As a result, an error component due to such an assembly error or a manufacturing error is included in the detection signal, and it may not be possible to detect angular acceleration with high accuracy.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to suppress an error in a detection signal caused by an assembling error of each disk and a manufacturing error of each slit, and to perform an angular acceleration capable of performing highly accurate angular acceleration detection. It is to propose an acceleration detecting device.

[0015]

As shown in FIG. 5, an angular acceleration detecting device 100 according to the present invention is fixed to a rotating shaft 101 so as to rotate integrally with a rotating shaft 101 and has a first and a second facing each other. It has second disks 102 and 103.

The first disk 102 is rigid and has a first slit group 104 arranged in the circumferential direction. The first slit group 104 is formed, for example, by cutting a rigid disk into a fan shape at a constant angular interval. By the first slit group 104, a plurality of fan-shaped first blade portions 105 are formed at equal angular intervals.

The second disk 103 has a slit forming portion in which a second slit group 106 arranged in the circumferential direction is formed, and this slit forming portion is
And a spring portion 107 that elastically displaces in the circumferential direction in accordance with the angular acceleration acting on the spring 3. For example, the second disk 102 is a shaft fixed portion 1 fixed to the rotating shaft 101.
And a spring portion 107 made of a leaf spring radially extending at equal angular intervals from the outer periphery of the spring 08. Further, a plurality of second slits radially formed at a constant angular interval are provided on the outer periphery of the spring portion 107. A plurality of fan-shaped second blade portions 109 defined by forming the group 106 are defined.

Further, a fan-shaped blade portion 105 formed by the first slit group 104 and a fan-shaped blade portion 10 formed by the second slit group 106 are formed.
9, a pair of annular electrode plates 111 and 112 fixedly supported on the device housing 110 side are opposed to each other.

When the rotating shaft 101 rotates while a voltage is applied between the pair of annular electrode plates 111 and 112, the first and second disks 101 and 102 fixed to the outer periphery of the rotating shaft 101 are integrally formed. Rotate. Rotating shaft 10
1, the second slit group 106 or the second blade portion 109 of the second disk 103 provided with the spring portion 107 is moved to the first slit group 104 of the first disk 102 or First blade portion 105
Relative to the circumferential direction.

As a result, the area of the overlapping portion of the two blade portions 105 and 109 indicated by oblique lines in FIG. 5B fluctuates. Here, since the first and second blade portions 105 and 109 are opposed to each other at a fixed interval with a pair of ring electrode plates 111 and 112 interposed therebetween, the first and second blade portions 104 and 104 are fixed by the ring electrode plate 111 and the first blade portion 104. A capacitor having a capacity is formed, and the other electrode plate 112 and the second blade portion 109 are formed.
Forms a capacitor having the same constant capacity, and furthermore, the first and second blade portions 105 and 109 whose overlapping areas vary due to relative displacement form a variable capacitor. That is, an equivalent circuit as shown in FIG. 5C is formed.

Therefore, the first and second blade portions 10
The relative displacement of the first and second blade portions 105 and 109 can be obtained by detecting the capacitance of the variable capacitor formed by the capacitors 5 and 109.
From this result, the angular acceleration occurring on the rotating shaft 101 can be calculated.

The first and second disks 102,
First and second slit groups 10 to be formed in 103
The shape of each of the discs 106 and 106 is not limited to the above-mentioned sector shape as long as the overlapping area between the discs fluctuates according to the relative displacement generated between the discs. It may be.

Here, generally, a method utilizing frequency modulation can be employed as a means for detecting a change in capacitance. In this method, a frequency change caused by a change in capacitance is detected as voltage conversion by F / V conversion. In this case, since the frequency change is inversely proportional to the capacitance change, the frequency change for the capacitance conversion becomes non-linear, and the process for calculating the angular acceleration becomes complicated. As a countermeasure, the frequency change and the angular acceleration may be in a linear relationship by devising the slit shapes of the first and second disks. For example, a method of forming a group of slits such that an overlapping portion of the first disk and the second disk is an area defined by a curve is conceivable.

[0024]

As described above, in the angular acceleration detecting apparatus according to the present invention, the circumferential direction generated between the first slit group of the first disk and the second slit group of the second disk. Is detected as a change in capacitance indicating a change in the area of the confronting portion of the slit group of both disks irrespective of the amount of movement of the intersection of these slit groups in the radial direction.

Therefore, unlike the conventional case where the movement of a point which is the intersection of the slit group is detected, the error component included in the detection signal caused by the mounting error of each disk, the manufacturing error of the slit group, etc. As a result, highly accurate angular acceleration detection can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing the structure of an angular acceleration detecting device.

FIGS. 2A and 2B are a front view and a sectional view showing a shape of a second disk of the apparatus of FIG. 1;

FIG. 3 is an explanatory diagram showing a relationship between slit groups of the apparatus of FIG. 1;

4 is a block diagram showing a configuration of an optical sensor of the apparatus of FIG. 1 and a signal processing circuit for a sensor output signal.

5A is a longitudinal sectional view showing a main part of an angular acceleration detecting device to which the present invention is applied, and FIG.
FIG. 3C is a partial plan view showing the first and second slit groups formed on the first disk and FIG. 2C is a circuit diagram showing an equivalent circuit including the first and second disks and a counter electrode plate.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 angular acceleration detecting device 101 rotating shaft 102, 103 disk 104 first slit group 105 first blade portion 106 second slit group 107 spring portion 108 shaft fixed portion 109 second blade portion 111, 112 annular electrode plate

Claims (3)

[Claims] 1. A semiconductor device comprising: a first disk and a second disk fixed so as to rotate integrally with a rotation shaft and opposed to each other, wherein the first disk is rigid and is arranged in a circumferential direction; The second disk is provided with a second slit group arranged in a circumferential direction, and a slit forming portion in accordance with an angular acceleration acting on the disk. And a spring portion for elastically displacing in the circumferential direction by using the first slit group and the second slit group, and capable of detecting an angular acceleration generated on the rotation axis based on a relative displacement between the first slit group and the second slit group. In the apparatus, a pair of ring-shaped electrode plates are disposed opposite to each other at a fixed position with the first slit group and the second slit group interposed therebetween, and the first and second disks are arranged in a circumferential direction. To displacement Therefore, a change in the overlapping area of the first and second disks that changes is detected as a change in capacitance, and the angular acceleration generated on the rotation axis is obtained based on the change in capacitance. Capacitive angular acceleration detector. 2. The method according to claim 1, wherein a frequency change caused by the change in capacitance is detected as a voltage change by performing F / V conversion, and an angular acceleration generated in the rotation axis is obtained based on the voltage change. A capacitance type angular acceleration detecting device characterized by the above-mentioned. 3. The capacitance-type angular acceleration detecting device according to claim 2, wherein the frequency change and the angular acceleration are set to have a linear relationship.