JP2003161636A - Device for detecting angle of rotation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detector with a simple structure which can be adapted to a narrow place, accurately carries out the measurement in non-contact, has such an environmental property that the fluctuation of outputs caused by the temperature, the external magnetism or the like is reduced, particularly has a large degree of freedom for a relative mounting position between a detecting coil and a conductive body (or magnetic body), and can freely change the detection sensitivity while carrying out matching a detection circuit by changing the structure of overlapping distance or overlapping area of a conductive body for many applications. <P>SOLUTION: The detection section is composed of a pattern which is formed on the peripheral surface of a spindle-like rotating body (11) in accordance with a certain function, and has conductivity or magnetic resistance different from the spindle-like rotating body and a coil (1) arranged close to the pattern. Then, the detection section is periodically applied with pulse-like voltage so as to cause a capacitor (4) to charge or discharge, and a period is measured until the voltage at the discharge time exceeds a threshold of a comparator (5), and the angle of rotation is detected by converting the period into a value of voltage or the like. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small, environmentally-friendly place where voltage, current, and switch output are detected by sensing a rotational angle displacement amount to determine whether or not it is at a predetermined position and the position itself. The present invention relates to a rotation angle detector used for the purpose of generating, etc.

[0002]

2. Description of the Related Art As a conventional detector for detecting a rotational position,
Although there are potentiometers, resolvers, optical encoders, etc., since the potentiometers are of the sliding type, there is a problem that the sliding parts wear when used for a long time and the rotational driving torque also fluctuates. Similarly, the resolver also needs to extract the signal of the stator winding with a brush, and has a drawback that the size in the diameter direction is relatively large. Since the optical encoder has a mechanical limitation in forming a slit through which light passes, when an attempt is made to increase the resolution, the size becomes large in the axial direction. In addition, due to miscounting due to noise and the like, repeated stability was lacking and mechanical strength was low.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a small-sized rotation angle detector having a simple structure and excellent resistance to external environmental changes such as temperature and humidity, excellent mechanical strength, and the like.

[0004]

[Means for Solving the Problems] A shaft-shaped rotating object (1
Formed on the outer circumference of 1) with a constant function in the circumferential angular direction 2
By forming a conductor or magnetic material surrounded by a straight line (or a curve) and changing the shapes of the pattern (2) and the coil (1) having different conductivity or magnetoresistance, the inductance determined only by the difference in material. The structure is such that the output characteristics can be actively designed instead of the change amount. By combining this with an electric circuit that processes the amount of change in inductance, it is possible to provide a rotation angle detector for various purposes.

As an example, a coil is installed on the outer circumference or side surface of a rotation angle detecting portion formed by covering a shaft-shaped non-conductor with a conductor or a magnetic substance, and a resistor, a capacitor, a comparator or a fixed frequency pulse oscillator. And a periodic rectangular wave oscillating circuit and a processing circuit for a coil composed of a voltage trigger unit, a periodic voltage converting unit (21) and the like.

The rotation angle detector of the present invention has a configuration shown in the blotter diagram of FIG. 1 or 7. The coil (1) is fixed in close proximity to the pattern (2) having different conductivity or magnetic resistance on the inner diameter, the side surface or the outer circumference. Patterns with different conductivity or magnetoresistance (2)
Are formed on the outer periphery of the shaft-shaped rotating body (11). When the rotation angle measurement object (15) rotates in the rotation direction of FIG. 1, the overlapping distance (10) or the overlapping area with the adjacent coil (1) changes.

FIGS. 1 and 7 show a circuit in which this change in the superposed state is recognized as a change in the inductance of the coil. In either method, the coil inductance is the same as the change in time, but the oscillation circuit applied by the coil and the take-out time are different. The comparator (5) used in the pulse output circuit is an inverting output comparator. When the input voltage rises from a low voltage, it outputs a high level until it exceeds the threshold, and when it exceeds the threshold, it outputs a low level. Is output.
When the input voltage drops from the high voltage side, a low level is output until the input voltage exceeds the threshold value, and a high level is output when the input voltage exceeds the threshold value. Moreover, by providing the threshold with hysteresis, continuous oscillation can be stably continued. In addition to this, an operational amplifier or a Schmitt inverter having a logic element can be used as a substitute for the comparator.

A circuit using a fixed frequency pulse oscillator (9) used for a pulse output section, a flip-flop circuit (8) and a comparator (5) controls the output timing of the pulse to compensate the temperature only by hardware. It can be used for adjusting characteristics and improving linearity. The periodic voltage conversion unit (21) is a unit that converts the time obtained by determining the transient state of capacitor discharge with a threshold value of a comparator into a voltage, and the periodic voltage conversion unit (21).
A voltage or current corresponding to the displacement is output, but a switch output is generated by comparing / determining whether it is on the plus or minus side with respect to a preset displacement.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In this angle detector, when a pulsed voltage is applied to a coil (1) from a comparator (5), a pattern (2) or magnetism having different conductivity or magnetic resistance of a rotation angle detector is obtained. The inductance of the coil (1) changes according to the amount by which the body and the coil (1) are overlapped, and the voltage at the comparator input part changes accordingly. When the pattern (2) having different conductivity or magnetic resistance is brought close to the coil (1), the magnetic flux generated from the coil causes an eddy current on the surface of the pattern (2) having different conductivity or magnetic resistance. Occurs,
This acts as a loss and acts in the direction of reducing the inductance, and when a magnetic body is inserted, the magnetic body functions to concentrate the magnetic flux generated from the coil and increases the inductance.

FIG. 7 shows a block diagram of continuous oscillation using a comparator having hysteresis, and FIG. 8 shows that when a pulsed voltage is applied from the comparator to the coil, the capacitor has a time constant determined by the inductance of the coil, the resistance and the capacitor. Shows how the battery is charged. The pole on the charged side of the capacitor is also connected to the input side of the comparator, so if the voltage rises above the threshold of the comparator, the output of the comparator will be 0 V (volt) or ground as shown in FIG. The capacitor starts to discharge. At this time, the capacitor discharges electric charge with a time constant determined by the inductance of the coil, the resistance, and the capacitor.

When the discharge voltage drops below the threshold value of the comparator, the output of the comparator changes to the high level, so that the oscillation continues continuously and the time until the high level is reached (the period Td in FIG. 8). It is converted into voltage and output. In addition, even if there is no hysteresis in the threshold of the comparator, oscillation may be maintained due to overshoot due to the back electromotive force of the coil, but it is unstable.
Hysteresis is provided in the threshold value of the comparator to sufficiently secure the potential difference (difference between VH and VL) ΔV shown in FIG.
It is important to oscillate stably.

Next, a method of observing a voltage change of charging / discharging of the capacitor, converting it to a voltage and outputting it will be described. A rectangular wave T having a constant time width in synchronization with the output voltage inversion timing of the comparator that is continuously oscillating
By generating c and taking the effective value of the rectangular wave, it is possible to generate an output voltage. In this way, in the output voltage generation method, assuming that the output cycle of the comparator is T, the output voltage becomes Tc / T, and the cycle T changes when the execution value is obtained. Therefore, the inductance of the coil is proportional to the output voltage. The relationship is damaged.

Therefore, a fixed pulse oscillator circuit is added separately,
A pulsed voltage is applied to the coil while the output of the comparator is inverted from the rising edge of the clock that operates in cycle T, and a rectangular wave is generated based on the signal that passes the threshold of the comparator when the capacitor is discharged. Then, if this time Td is taken as the effective value, the output becomes Td / T, and the cycle T
Is constant, an output proportional to the change in inductance can be obtained.

This method has the same effect even if the pulse is output a plurality of times within the period T, and when the output that can be obtained with a small inductance is small due to the restriction of the shape of the coil or the like, the output is within one period of the clock. A stable output can be obtained by outputting the pulse voltage a plurality of times to save time. As another voltage conversion method, it is possible to measure the time taken for the capacitor to pass through the threshold value when discharging the capacitor and output a voltage proportional to the time.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In FIG. 1, a pattern (2) having different conductivity or magnetoresistance that is rigidly fastened to a linear displacement detected object (15) is used, and the coil is superposed with the coil (1) along with the displacement of the position. By arranging so that the distance or the overlapping area changes, the displacement detecting unit is configured, and the coil (1)
A resistor (6), a buffer (7), a flip-flop circuit (8), and a fixed frequency pulse oscillator (9) are connected to one end of, and a capacitor (4) is connected between the coil (1) and the comparator (5), Its end is grounded to 0V (volt) or ground (3).

Further, a fixed frequency pulse is generated from the fixed frequency pulse oscillator (9), and the output voltage of the inverting output comparator (5) having a threshold value having hysteresis according to the change of the inductance of the coil (1) is When the preset upper limit voltage VH is reached, the reset circuit of the flip-flop circuit operates to discharge the voltage of the coil (1) and the comparator, and a trigger is applied at the moment when this voltage reaches the preset lower limit voltage VL, from the fixed frequency pulse oscillation. The time Td until reaching the predetermined lower limit voltage VL is measured.

In FIG. 1, a shaft-shaped rotating body (11) is provided on the outer periphery of the coil (1), and a pattern (2) having a conductivity or a magnetic resistance different from that of the shaft-shaped rotating body as shown in FIGS. ) Is printed. Here, what is called printing is a paint method in which a solvent or an adhesive is kneaded and coated to form a pattern (2) having different conductivity or magnetoresistance, an electroplating method, a vacuum deposition method, an ion plating method. It also includes vacuum film forming methods such as the towing method and the sputtering method.

The gradient extraction is also included by controlling the ion extraction density by the ion extraction method in vacuum. As a material for the pattern (2) having different conductivity or magnetic resistance, non-ferrous metal having a low electric resistivity such as copper, silver and aluminum alloy is often used. For the shaft-shaped rotating body (11), various polymer materials, ceramics and the like are used in addition to steel, stainless steel, non-ferrous metal. Printing thickness is 20μm to 300μ
about m. The film formation by the sputtering method is precise and suitable for a fine shape, and strong and uniform printing is possible.

FIG. 1 shows a case where the outer circumference of the coil (1) is close to the pattern (2) having different conductivity or magnetic resistance via the coil fixing base (13). In this case, the axial center of the conductor printing and the axial center of the coil (1) need to be on the same plane. FIG. 1A shows a case where the side surface of the coil (1) is closely fixed via a coil fixing base (13). In this case, it is necessary that the axis of the coil faces the axial center of the printed conductor.

FIG. 2 shows an example in which a pattern (2) having different conductivity or magnetic resistance is printed on the outer periphery of the shaft-shaped insulator (11). FIGS. 3 to 6A are developed views showing the shape of the print on the outer periphery thereof. FIG. 3 shows an example in which the conductor area decreases in the circumferential direction in proportion to the angle at which the conductor area becomes minimum at 360 degrees.

FIG. 4 shows the conductor area from the maximum to 36 in the circumferential direction.
Although it becomes the minimum at 0 degree, it is set as a conductive area which is surrounded by two curves by a function curve and sharply decreases. By doing this, the decrease in the conductive area changes sharply with respect to the angle, and the change in the conductance that occurs in the coil with respect to the change in the angle also decreases sharply.
The resolution becomes steep.

FIG. 5 shows a circular rotor having different diameters in the circumferential direction and a pattern (2) having different conductivity or magnetic resistance.
Are arranged in a zigzag pattern in the circumferential direction, and the density is changed within 360 degrees from the maximum density to zero at the minimum density. Specifically, d
1, d2 ... dn, and the interval is p. In FIG. 5A, the intervals between adjacent circular rows of the same diameter are p1, p2 ...
-By increasing the pn and the interval, the conductive area density changes to zero within 360 degrees from the maximum. FIG. 6 shows the density of the conductor ion density in the circumferential direction by the ion extraction method, and the density ratio is 5: 1 or more.

When the coil is close to the side surface (FIG. 1A), the print width of the pattern (2) having different conductivity or magnetic resistance is about 1 to 2 times the outer diameter of the coil.

[0024]

According to the present invention, in addition to the fact that the rotation angle detector can be constituted by only the coil (1), the shaft-shaped rotor and the pattern (2) having different conductivity or magnetic resistance,
Due to the effect of conductor printing, it has become possible to detect the rotation angle with a steeper sensitivity.

In addition, it is possible to perform contactless measurement with a rotating object to be measured, and the coil (1) and the shaft-shaped rotating body (2) having different conductivity or magnetic resistance relative to each other such as space and parallelism. The large position has a relatively large degree of freedom and does not require a fine positional adjustment, which is a great effect in use.

If the shape of the conductor is selected according to the dimensions of the object to be measured, a narrower detecting section can be produced with sufficient sensitivity and accuracy by matching with the circuit. Since the detection unit is composed only of the coil and the conductor (or the magnetic substance), it is easy to deal with the environmental measures to be installed, and especially the high temperature measure and the moisture resistance measure are also easy.

[Brief description of drawings]

FIG. 1 is an overall block diagram of a rotation angle detector that detects a rotation angle.

FIG. 1A shows a detection unit near a side surface of a coil (1) of a rotation angle detection unit.

FIG. 2 is a bird's-eye view showing an example of a conductor on the outer periphery of a shaft-shaped insulator.

FIG. 3 shows a case where the conductor area is reduced in proportion to the circumferential angle of the conductor.

FIG. 4 shows an example in which a conductor area is sharply reduced in proportion to an angle in a pattern (2) having different conductivity or magnetoresistance surrounded by a curve in which the conductor is a function of a constant angle.

FIG. 5 is an example in which circular conductors having one row of conductors are arranged along the axial length direction so that the intervals are the same and the diameters gradually decrease, and the conductor area density is reduced in a zigzag arrangement in the circumferential direction. Indicates.

FIG. 6 shows that the conductors are circular conductors arranged along the axial length direction and the intervals between them are gradually widened, and the rows are arranged in a zigzag pattern in the circumferential direction, and the maximum angle is within 360 degrees. An example of changing the density from the minimum density will be shown.

FIG. 7 is an overall block diagram of a rotation angle detector in which the oscillation method is different from that in FIG.

FIG. 8 is a timing chart of FIG.

9 is a timing chart of FIG. 7.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 coil 2 a pattern different in conductivity or magnetic resistance from an axial rotating body 3 grounding section 4 capacitor 5 inverting output comparator 6 having a threshold value having hysteresis 6 resistance 7 buffer 8 flip-flop element 9 fixed frequency pulse oscillator 10 Stacking distance 11 Shaft-shaped rotating body 12 Shaft rotation 13 Coil fixing base 14 Bearing 15 Rotating angle measurement object 21 Transmission frequency voltage conversion unit 22 Output conversion unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Miki             102 Shichijo Goshonouchi Minami-cho, Shimogyo-ku, Kyoto-shi, Kyoto Prefecture             Address inside Ribex Co., Ltd. F term (reference) 2F077 AA41 CC02 FF02 FF13 FF31                       NN19 PP06 TT82

Claims (4)

[Claims] 1. A coil (1) and a shaft-shaped rotating member (11) installed on the inner circumference, outer circumference or side surface of the coil (1), and the shaft-shaped rotating member (11) is mounted on the outer periphery of the shaft-shaped rotating member (11). A pattern (2) having different conductivity or magnetic resistance as compared with 11) is formed by changing the area, density, or thickness in the circumferential direction of the outer circumference of the shaft-like rotating body (11) in a constant functional relationship with the angle. Or, when the coil (1) is printed and a rectangular wave is periodically applied to the coil (1), the overlapping distance (10) or the overlapping area or density changes depending on the rotation angle. Also, since the eddy current loss and the inductance change and the attenuation state of the rectangular wave changes depending on the position state of the pattern (2) having different conductivity or magnetic resistance, the rotation angle can be detected by measuring the attenuation state of the rectangular wave. Rotation angle detection vessel. 2. A coil (1), and a shaft-shaped rotating member (11) is installed on the inner circumference, outer circumference or side surface of the coil (1), and the shaft-shaped rotating member (11) is mounted on the outer periphery of the shaft-shaped rotating member (11). The pattern (2) having different conductivity or magnetic resistance as compared with 11)
An area, a density, or a thickness is formed in the circumferential direction of the outer circumference of the shaft-like rotating body (11) with a constant functional relationship with the angle by changing the shading by the metal ion extraction method, and is periodically formed in the coil (1). When a rectangular wave is applied, the overlap distance (10) or overlap area changes depending on the angle, so the coil (1)
Since the eddy current loss and the inductance of the pattern (2) having different conductivity or magnetic resistance change and the attenuation state of the rectangular wave changes, the attenuation state of the rectangular wave can be measured so that the rotation angle can be detected. Rotation angle detector. 3. The rotation angle detector according to claim 1, wherein a resistor (6), a buffer (7), a flip-flop element (8) and a fixed frequency pulse oscillator (9) are connected to one end of the coil (1). Then, the other end of the coil (1) is connected to the comparator (5) having a threshold value having hysteresis, and the other end is connected to the reset part of the flip-flop circuit (8), and the coil (1) and the comparator ( The capacitor (4) is connected between 5), and the other end is grounded to the ground (3), and the inner circumference of the coil (1) or A pattern (2) that moves on the outer periphery or in the vicinity is provided, and the pattern (2) is different in conductivity or magnetic resistance from the coil (1).
It is configured such that the inductance of the coil (1) changes according to the distance with or the overlapping distance (10) or the overlapping area, and a fixed frequency pulse is generated from the fixed frequency pulse oscillator (9) to generate a fixed frequency pulse of the coil (1). The input voltage of the comparator (5) having a threshold value having hysteresis according to the change of the inductance is the preset upper limit voltage V
When it reaches H, the reset circuit to the flip-flop element operates and the output of the buffer (7) becomes the ground level, so that the voltage between the coil (1) and the comparator (5) is discharged, and this voltage becomes the lower limit voltage VL. When it reaches, the trigger is activated to fix the time, the time Td from the rise time of the fixed frequency pulse to the lower limit voltage VL is measured, and this time is regarded as the angle / rotation speed, and the rotation angle detector detects the angle. 4. The rotation angle detector according to claim 1, wherein a resistor (6) and a capacitor (4) are connected to one end of the coil (1), and the oscillation period voltage converter is connected to the other end of the coil (1). Connect (21), resistor (6) and capacitor (4)
Output of the comparator (5) having a threshold value having hysteresis by connecting an inverting output comparator (5) having a threshold value having hysteresis between Oscillate to move the inner peripheral portion (or outer peripheral portion, or the vicinity) of the coil (1) according to the angle to be measured and the rotation angle / rotation number of the object to be measured (12), which has different conductivity or magnetic resistance ( 2) is provided, and depending on the overlapping distance (10) of the coil (1) and the pattern (2) having different conductivity or magnetic resistance, or the distance between the coil (1) and the pattern (2) having different conductivity or magnetic resistance. When the inductance of the coil (1) is changed, the impedance of the coil (1) and the resistance (6) changes, so that the charging / discharging time of the capacitor (4) changes. Since a change in the oscillation period of the comparator (5) outputs the rotation angle detector that period was observed, angle detecting changes in this period is regarded as the rotation angle and rotation speed.