JP2003139812A - Apparatus for detecting breaking of wire, location detecting apparatus, and apparatus for detecting angle of rotation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for detecting the breaking of a wire for detecting the breaking of a wire in coils, a location detecting apparatus and an apparatus for detecting the angle of rotation provided with the same. SOLUTION: Resistors R and the coils L1-L4 are serially connected, and opposite-phase A.C. signals V1 and V2 are each impressed. It is determined by XOR circuits 61-64 whether detection signals outputted from nodes of the coils L1-L4 and the resistors R are in phase with the A.C. signal V1 impressed on the side of the resistors R or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire breakage detecting device for detecting wire breakage of a coil, and a position detecting device and a rotation angle detecting device having a coil for outputting a detection signal according to a change in distance from a magnetic material.

[0002]

2. Description of the Related Art As a position detecting device and a rotation angle detecting device, there are devices provided with a coil and a magnetic material. For example, as shown in FIG. 4A, the rotor 2 made of a magnetic material that rotates in an eccentric state about the axis O and the cylindrical stator 4 having the axis O as the central axis are provided at equal intervals. There is a rotation angle detection device provided with four coils L1, L2, L3, L4. Since the rotor 2 rotates in an eccentric state, the distance between the rotor 2 and the coils L1, L2, L3, L4 changes according to the rotation.

A magnetic body and coils L1, L2, according to the rotation
Since it suffices if the distance between L3 and L4 changes, for example, in FIG.
As shown in (a), the magnetic body 8 is provided on the outer peripheral portion of the non-magnetic rotor 9, or as shown in FIG. 5 (b), the magnetic body 8 is provided on the outer peripheral portion of the non-magnetic rotor 9 at equal intervals. 8 can be attached. Further, as shown in FIG. 5C, by forming the rotor (magnetic body) 8 in a quadrangular shape, the distance between the coil and the rotor can be changed according to the rotation without eccentricity.

Further, as shown in FIG. 4B, a magnetic body 6 which moves linearly and four coils L1, L2, L3 and L4 which are provided at equal intervals in the moving direction of the magnetic body 6 are provided. There is a position detection device. The distance between the magnetic body 6 and each coil L1, L2, L3, L4 changes according to the movement of the magnetic body 6.
In any of the configurations of FIGS. 4A and 4B, the rotor 2 or the magnetic body 6 is connected to the coils L1, L2, L3, and L4.
A detection signal corresponding to the distance to and is output.

FIG. 6 and FIG. 7 show an example of the structure of a position detecting section for detecting position data representing a rotation angle or position based on a detection signal. As shown in FIG. 6, the coils L1, L2,
Resistors R, R, R, and R are connected in series to L3 and L4, respectively, and four coils and resistors (R-L) are connected in series.
1, R-L2, R-L3, R-L4) are connected in parallel, and an AC signal (Esinωt) is applied. Coil L
1, L2, L3, L4 and the rotor 2 detect the detection signal Vsinθsinωt, which includes the rotation angle θ component of the rotor 2 from the connection point of the resistor R and the coils L1, L2, L3, L4.
Vcos θ sin ωt, −V sin θ sin ωt, −V
It is configured such that cos θ sin ωt is output respectively.

Here, in the linear movement of the magnetic body 6 shown in FIG. 4 (b), the coils L1, L2, L3, L4 and the magnetic body 6 have a resistance R and coils L1, L2, L3, L4. The detection signal Vs corresponding to the displacement x of the magnetic body 6 from the connection point
inxsin ωt, Vcosxsin ωt, −Vsin
xsin ωt, −Vcosxsin ωt is output. Hereinafter, the rotation angle θ of the rotor 2 will be described as an example, but the displacement x of the magnetic body 6 can be treated in the same manner as the rotation angle θ of the rotor 2.

Detection signals from the coils L1 and L3 (± Vs
in θ sin ω t) is subtracted by the differential amplifier 10 to obtain As
in θsin ωt is output. Also, the coils L2, L
The detection signal (± V cos θ sin ωt) from 4 is subtracted by the differential amplifier 12, and A cos θ sin ωt is output.

As shown in FIG. 7, the phase of Asin θ sin ωt output from the differential amplifier 10 is shifted by 90 ° in the phase shift unit 26, and Asin θ cos ωt is output. Asin θc output from the phase shift unit 26
osωt and Acos θ output from the differential amplifier 12
The sinωt is added and subtracted by the adder 28 and the subtractor 30, respectively. Asin output from the addition unit 28
(Ωt + θ) and Asin output from the subtraction unit 30
(Ωt−θ) is converted into pulse signals by the comparators 32 and 34, and latched by the latch units 36 and 38, respectively.

The latch units 36 and 38 are provided with a pulse signal (Asin (ωt ± θ)) at the clock interval of the counter 20.
Latch the zero-cross part of. The clock of the counter 20 is also sent to the sin wave generation unit 22, and the sin wave generation unit 2
The sin signal generated based on the clock in 2 is D /
The A conversion unit 24 converts the analog signal and outputs Esin ωt shown in FIG. The data latched by the latch units 36 and 38 is sent to the position data generation unit 40, and the phase difference is generated based on the zero-cross time of the pulse signal (Asin (ωt ± θ)) and the Esinωt cycle reference time (ωt = 0). θ is detected, and the rotation angle θ of the rotor 2 is output as position data.

[0010]

If the coil is broken, accurate position data cannot be obtained. As a method of detecting the disconnection, for example, as shown in FIGS. 8A and 8B, from the cycle reference time (ωt = 0) to Asin (ω
(t ± θ) P data or M data representing the time until the rise or fall of the pulse signal is detected, and P data
There is a method of monitoring the data and the S data, which represents the average of the M data. P data and M data are Asin (ωt
± θ) phase ± θ (position data).

Since the P data and the M data represent the phase ± θ, the S data is kept constant as shown in FIG. 8 (a). At the time of disconnection, as shown in FIG. 8B, the P data and the M data change, so the S data also changes.
Therefore, when the variation of the S data exceeds the threshold value, it can be determined that the disconnection has occurred. However, since the S data in the disconnected state is constant, if the S data is disconnected from the beginning, the disconnection cannot be detected from the variation of the S data.

There is also a method of detecting the disconnection by monitoring the rising or falling of the pulse signal of Asin (ωt ± θ). However, for example, when any one of the coils is disconnected, since the sin wave is input to the differential amplifier 10 or 12 via the resistor R connected in series with the disconnected coil, it is different from the normal time, The pulse signal is output from the comparators 32 and 34. Since the pulse signal is output, the disconnection is not detected.

Further, since Asin (ωt ± θ) input to the comparators 32 and 34 exceeds the threshold value,
There is also a method of detecting disconnection. When the disconnection occurs, signals added and subtracted by the adder 28 and the subtractor 30 change, so that the waveform of Asin (ωt ± θ) is distorted and a part thereof is saturated. A disconnection can be detected by this saturation. However, if the coils L1 and L3 are broken or the coils L2 and L4 are broken, Asin (ωt
± θ) is Acosθsinωt or Asinθcos
Since it is ωt, the amplitude does not change, and the disconnection cannot be detected.

As described above, the disconnection may not be detected depending on conditions such as the timing of the disconnection, the combination of the disconnected coils, and the displacement position.

The present invention has been made in view of the above circumstances, and the phase of the detection signal output from the connection point of the coil and the resistor connected in series and the AC signal applied to the resistor and / or the coil. An object of the present invention is to provide a wire breakage detecting device that can detect wire breakage of a coil from a change in phase relationship by providing a means for determining a relationship. Another object of the present invention is to provide a disconnection detection device capable of preventing erroneous detection of coil disconnection by providing a means for invalidating the determination result that is temporarily determined to be in phase (or reverse phase). .

Further, the present invention provides a position detecting device and a rotation angle detecting device, which are provided with means for determining a phase relationship between the AC signal and the detection signal, and which can detect disconnection of a coil from a change in the phase relationship. The purpose is to do. Further, by providing a means for invalidating the determination result that is temporarily determined to be in phase (or reverse phase), a position detection device and a rotation angle detection device that can prevent erroneous detection of coil disconnection are provided. The purpose is to

[0017]

A wire breakage detecting device according to a first aspect of the present invention is a wire breakage detecting device for detecting wire breakage of a detector having a coil, wherein a resistor having one terminal connected to one terminal of the coil. And an applying unit that applies an AC signal to the other terminal of the resistor and / or the coil, and a determining unit that determines a phase relationship between the AC signal and a detection signal output from the one terminal. Is characterized by.

In such a wire breakage detecting device, the judgment means can judge the phase relationship between the AC signal applied from the applying means and the detection signal, and the wire breakage of the coil can be detected from the judgment result. The disconnection of the coil includes the disconnection of the connection wire with the coil element.

In the disconnection detecting device according to the second invention, in the first invention, the applying means applies the first AC signal to the other terminal of the resistor, and outputs the first AC signal and the one terminal. The second AC signal having a phase opposite to that of the first AC signal is applied to the other terminal of the coil so that the detected signal has a phase opposite to that of the detected signal. It is characterized in that whether or not the AC signal and the detection signal are in phase or whether or not the second AC signal and the detection signal are in phase.

In such a disconnection detecting device, the first AC signal and the detection signal have opposite phases by the applying means. Therefore, when determining the phase relationship between the first AC signal and the detection signal, the determining unit normally determines that the phase is reversed. When the coil is broken, the detection signal becomes an output from the resistor to which the first AC signal is applied, and the detection signal and the first AC signal have the same phase. Therefore, the determination means determines that they are in phase. Since the determination means determines that the coils are in phase, the coil disconnection can be detected. It is also possible to determine the phase relationship between the second AC signal and the detection signal instead of the first AC signal by the determination means. In this case, it is determined that the normal phase is the same phase, and the disconnection is the reverse phase.

The disconnection detecting device according to a third aspect of the present invention is the disconnection detecting device according to the second aspect of the invention, wherein the determination result is that the phase is temporarily determined to be in-phase due to the fluctuation of the first AC signal or the detection signal, or the second AC signal or It is characterized by further comprising means for invalidating a determination result which is temporarily determined to be in a reverse phase due to a change in the detection signal.

In such a disconnection detecting device, the first AC signal and the detection signal may be in phase even if the coil is not disconnected due to, for example, a phase error between the first AC signal and the detection signal. By the means for invalidating the determination result, it is possible to invalidate the in-phase determination for such a short time. When the phase relationship between the second AC signal and the detection signal is determined, the determination result that is temporarily determined to be in the opposite phase is invalidated. By invalidating the determination result that is temporarily determined to be in-phase (or reverse-phase), erroneous detection of coil disconnection can be prevented.

A position detecting device according to a fourth aspect of the present invention includes a coil and a magnetic body that moves while changing the distance between the coil and the coil. The position sensor is output from the coil and changes according to the distance from the magnetic body. A position detecting device for detecting the position of the magnetic body based on a detection signal includes the disconnection detecting device according to any one of the first to third inventions.

The position detecting device according to a fifth aspect of the present invention is the position detecting device according to the fourth aspect, wherein the detection signal is an AC signal having a phase difference depending on the position of the magnetic body with respect to the phase of the AC signal applied to the coil. And means for detecting the phase difference of the generated AC signal, and means for determining the position of the magnetic body based on the detected phase difference.

A rotation angle detecting device according to a sixth aspect of the present invention includes a coil and a magnetic body that rotates while changing the distance between the coil and the coil. The magnetic body is output from the coil and is output according to the distance from the magnetic body. In a rotation angle detection device that detects a rotation angle of the magnetic body based on a changing detection signal,
It is characterized in that the disconnection detection device according to any one of the first to third inventions is provided.

A rotation angle detecting device according to a seventh aspect of the invention is the sixth aspect.
In the invention, means for generating an AC signal having a phase difference corresponding to a rotation angle of the magnetic body from the detection signal with respect to the phase of the AC signal applied to the coil, and the phase difference of the generated AC signal. And a means for obtaining the rotation angle of the magnetic body based on the detected phase difference.

In the position detecting device and the rotation angle detecting device, the disconnection detecting device according to any one of the first to third inventions is provided so that the detection signal and the first AC signal have the same phase as described above. Or not (or the detection signal and the second
The coil disconnection can be detected by determining whether or not the AC signal has a reverse phase. Further, it is possible to invalidate the determination result that is temporarily determined to be in-phase (or opposite-phase) and prevent erroneous detection of coil disconnection.

In the position detecting device and the rotation angle detecting device, the resistor is connected to the coil in advance, and the detection signal is output from the connection point between the coil and the resistor. Therefore, the resistor connected to the coil in advance is used as it is. be able to. Further, in the rotation angle detection device, the rotational movement refers to movement for rotating the magnetic body by a certain angle around the rotation center point or the rotation center axis.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. 4 coils L
An explanation will be given by taking as an example the detection of the disconnection of the coils of the position detection device and the rotation angle detection device including 1, L2, L3, and L4.
For example, in the case of the rotation angle detecting device, as shown in FIG. 4A, they are arranged inside the stator 4 at 90 ° intervals. Further, in the case of the position detecting device, as shown in FIG. 4B, they are linearly arranged at equal intervals.

FIG. 1 shows an example of the disconnection detecting device according to the present invention. In series with the coils L1, L2, L3, L4, a resistor R,
R, R, and R are connected, and an AC signal Esinωt is applied to each of the four resistors and the coils connected in series. However, as shown in FIG. 2, an AC signal (first AC signal) V1 V1 = E / 2 × sinωt + Vr supplied from the AC signal supply unit 42 is applied to the terminal on the resistance R side, and the coil L1 is applied. An AC signal (second AC signal) V2 V2 = -E / 2 x sinωt + Vr supplied from the AC signal supply unit 44 is applied to the terminals on the (L2, L3, L4) side. The AC signals V1 and V2 have opposite phases to each other, and the AC signal V1 is applied to the resistor and the coil connected in series.
An AC signal Esinωt, which is the difference between 1 and V2, is applied.

The alternating-current signal supply section 42 is provided with an alternating-current signal Esin.
ωt is input, the amplitude and DC component of Esin ωt are adjusted, and the AC signal V1 is output. Further, the AC signal supply unit 44 receives the AC signal Esin ωt and receives the Esin ωt.
ωt is inverted, the amplitude and the DC component are adjusted, and the AC signal V2 is output.

The connection point between the coil L1 and the resistor R is connected to the negative terminal of the differential amplifier 51. Similarly, the connection point between the coil L2 and the resistance R, the connection point between the coil L3 and the resistance R, and the connection point between the coil L4 and the resistance R are differential amplifiers 52 and 5, respectively.
3, 54 is connected to the-terminal. Differential amplifier 51, 5
The DC components Vr (reference values for comparison) of the AC signals V1 and V2 are input to the + terminals of 2, 53, and 54. Further, the DC component Vr is input to the + terminal of the differential amplifier 46.
The alternating-current signal V1 is input to the-terminal of the differential amplifier 46.

The output terminals of the differential amplifiers 51, 52, 53, 54 are XOR (exclusive OR) circuits 61, 62, respectively.
It is connected to the input terminals of 63 and 64. Further, the output terminals of the differential amplifier 46 are respectively connected to the XOR circuits 61, 62, 6
It is connected to the input terminals of 3,64. XOR circuit 6
The output terminals of 1, 62, 63 and 64 are connected to the input terminals of an AND circuit 48 commonly provided for all the coils via LPFs (low pass filters) 71, 72, 73 and 74, respectively. ing.

AC signal supply section 42 and AC signal supply section 4
Reference numeral 4 operates as a means for applying alternating-current signals V1 and V2 having mutually opposite phases to a resistor and a coil connected in series. Further, the resistance value r of the resistor R and the coils L1, L2, L3, L4
The respective impedances ωL and R are such that r >> ωL (Equation 1). Since the resistance value r is sufficiently larger than the impedance ωL, in a normal state where no wire breakage occurs, as shown by the alternate long and short dash line in FIG. Detection signal and AC signal V1 output from the connection point of the resistor and the coil
And are in reverse phase. Since the AC signal V2 and the AC signal V1 have opposite phases, the detection signal and the AC signal V2 have the same phase under normal conditions.

In such a position detecting device and a rotation angle detecting device, it may happen that the resistance value r of the resistor R needs to be changed. A change in the resistance value r may cause adverse effects such as a change in the amplitude of the detection signal. However, as will be described later, the resistance R and the coils L1, L2, L
3, detection signal ± Vsin output from the connection point with L4
From θsinωt and ± Vcos θsinωt to Asin
Since (ωt ± θ) is generated and the position data is obtained based on the phase θ, it is hardly affected by the change in amplitude. Since the phase θ is detected in this way, even if the resistance value r is changed so as to satisfy the expression 1, it hardly affects the detection of the position data.

The differential amplifier 46 operates as a means for detecting the magnitude relationship between the AC signal V1 and the DC component Vr, and the differential amplifiers 51, 52, 53, 54 have the magnitude relationship between the detection signal and the DC component Vr. Operates as a means for detecting. For example, the level of the signal output when the DC component Vr is larger can be defined as the H level, and when it is smaller, it can be defined as the L level.

The XOR circuits 61, 62, 63, 64 are respectively provided corresponding to the respective detection signals, and are means for judging whether or not the respective detection signals are in anti-phase with the AC signal V1, in other words, respectively. It operates as a means for detecting that the detection signal of is in phase with the AC signal V1. For example, when the levels of the input signals are different from each other, an H level signal is output, and when both of the input signals are H level or L level, an L level signal is output. AND circuit 4
Reference numeral 8 operates as a means for determining whether or not all the detection signals have an opposite phase to the AC signal V1, in other words, a means for detecting that any detection signal has the same phase as the AC signal V1. The AND circuit 48 outputs an H level signal only when all the input signals are H level.

The LPFs 71, 72, 73, 74 are provided respectively corresponding to the respective detection signals, and operate as means for invalidating the judgment result temporarily judged to be in phase due to the fluctuation of the AC signal V1 or the detection signal. To do. For example, even if the coil is not broken due to time delay due to the coil component or noise, the AC signal V
1 and the detection signal may be in phase. Such a short-time signal fluctuation can be nullified by the LPFs 71, 72, 73, 74.

Next, detection of disconnection of the position detecting device or the rotation angle detecting device equipped with the disconnection detecting device according to the present invention will be described. Coil L1, L2, L3, L4 and resistance R,
The magnitude relationship between the detection signal output from the connection point with R, R, R and the DC component Vr as the reference value for comparison is detected by the differential amplifiers 51, 52, 53, 54, respectively. The magnitude relationship between the AC signal V1 and the DC component Vr is the differential amplifier 46.
Detected in.

The match / mismatch between the magnitude relationship detected by the differential amplifier 46 and the magnitude relationship detected by the differential amplifiers 51, 52, 53, 54 is determined by the XOR circuits 61, 62, 63 ,.
64, respectively. XOR circuits 61, 62, 63, 6
The match / mismatch detected in 4 is sent to the AND circuit 48,
An H-level signal is output only when all do not match.

When the coil is not broken, as shown in FIG. 3, the AC signal V1 and the detection signal are in opposite phases, so that the magnitude detected by the XOR circuits 61, 62, 63, 64 is large or small. The relationship becomes inconsistent, and the AND circuit 48 outputs an H level signal.

When the coil is broken, the AC signal V1 applied to the resistor R is output as a detection signal. Therefore, the detection signal corresponding to the broken coil and the AC signal V1 are output.
And the phase relationship detected by any of the XOR circuits 61, 62, 63, and 64 is the same, and the AND circuit 48
Outputs an L level signal. By switching the output from the AND circuit 48 to the L level, disconnection of the coil can be detected.

For example, it is possible to monitor the output from the AND circuit 48 and stop the position detection or the rotation angle detection when the output is switched to the L level. As shown in FIGS. 6 and 7, the rotation angle is detected by the resistor R and the coil L.
1, L2, L3, L4, and a detection signal Vsin θsinω that is output from a connection point with the rotor 2 and corresponds to the rotation angle θ of the rotor 2.
t, Vcos θ sin ωt, −V sin θ sin ωt,
It can be performed based on −Vcos θ sin ωt.
Further, also in the case of position detection, similarly to the detection of the rotation angle, the detection signals Vsinxsinωt, V corresponding to the displacement x of the magnetic body 6 are detected.
cosxsin ωt, −Vsinxsin ωt, −Vc
It can be performed based on osxsin ωt.

As shown in FIG. 6, the detection signals (± Vsinθsinωt) from the coils L1 and L3 are subtracted by the differential amplifier 10 to obtain Asinθsinωt (where A =
2 V) is output, the detection signals (± V cos θ sin ωt) from the coils L2 and L4 are subtracted by the differential amplifier 12, and A cos θ sin ωt (where A = 2 V) is output.

As shown in FIG. 7, Asin θ sin ωt output from the differential amplifier 10 is the phase shifter 26.
At 90 °, the phase is shifted by 90 °, and Asinθcosωt is output. Asin θ output from the phase shift unit 26
cosωt and Acos output from the differential amplifier 12
θ sin ωt is added to and subtracted from the addition unit 28 and the subtraction unit 30, respectively, and Asin output from the addition unit 28.
(Ωt + θ) and Asin output from the subtraction unit 30
(Ωt−θ) is converted into pulse signals by the comparators 32 and 34, and latched by the latch units 36 and 38, respectively.

The latch sections 36 and 38 are provided with pulse signals (Asin (ωt ± θ)) at the clock interval of the counter 20.
Latch the zero-cross part of. Latch portions 36 and 38
The data latched by is sent to the position data generator 40, and the phase difference θ is detected based on the zero-cross time of the pulse signal (Asin (ωt ± θ)) and the cycle reference time (ωt = 0) of Asinωt, The rotation angle θ of the rotor 2 is output as position data.

An example of determining the phase relationship between the AC signal V1 applied to the terminal on the resistance R side and the detection signal (the magnitude relationship with the comparison reference signal Vr) has been described above, but the AC applied to the terminal on the coil side has been described. The configuration may be such that the phase relationship between the signal V2 and the detection signal is determined. In that case, as shown in FIG. 3, the phase is normal when the state is normal, and the phase is opposite when the line is broken.

In the above-mentioned embodiment, alternating current signals having opposite phases are applied to both ends of the resistor and the coil, but the coil side is set to the ground level and the voltage Vr, which is the reference value for comparison, is set to the sin wave. The disconnection can be detected by the phase relationship between the signal (V1) applied to the resistance side and the detection signal. As shown in FIG. 3, signals of opposite phases (V
1, V2) is applied, the voltage V which is a reference value for comparison
Since r can be set to a constant value, it is possible to easily determine the phase relationship (size relationship).

Although the disconnection detection of the coil of the position detection device and the rotation angle detection device has been described as an example of the embodiment, the disconnection detection device of the present invention can detect the disconnection of the coil connection in any detector. You can

[0050]

According to the disconnection detecting apparatus of the present invention, the determining means can determine the phase relationship between the AC signal applied from the applying means and the detection signal, and the disconnection of the coil can be detected from the determination result. .

Further, according to the disconnection detecting device of the present invention, the first alternating signal and the detecting signal are normally in the opposite phase and the second alternating signal and the detecting signal are in the same phase by the application means. When the coil is broken, the detection signal becomes an output from the resistor to which the first AC signal is applied, the detection signal and the first AC signal are in phase, and the detection signal and the second AC signal are in opposite phase, The coil break can be detected from the change in the phase relationship.

Further, according to the disconnection detecting apparatus of the present invention, the determination result which is temporarily determined to be in phase (or opposite phase) can be invalidated by the means for invalidating the determination result.
It is possible to invalidate the in-phase (or opposite-phase) determination for only a short time, and prevent erroneous detection of coil disconnection.

Further, according to the position detecting device and the rotation angle detecting device of the present invention, by providing the above-mentioned disconnection detecting device, it is possible to judge the phase relationship between the detection signal and the first AC signal or the second AC signal. Thus, it is possible to detect disconnection of the coil. Further, it is possible to invalidate the determination result that is temporarily determined to be in-phase (or opposite-phase) and prevent erroneous detection of coil disconnection.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an example of a disconnection detection device according to the present invention.

FIG. 2 is a diagram showing a part of the disconnection detection device shown in FIG.

FIG. 3 is a diagram showing an example of a waveform diagram of first and second AC signals and a detection signal of the disconnection detection circuit shown in FIG.

FIG. 4A is a diagram showing an example of a coil and a magnetic body (rotor) of a rotation angle detection device, and FIG. 4B is a diagram showing an example of a coil and a magnetic substance of a position detection device.

5 is a diagram showing another example of the rotor shown in FIG.

FIG. 6 is a diagram showing a part of a position detection unit that detects position data.

FIG. 7 is a diagram showing a part of a position detection unit that detects position data.

FIG. 8 is a diagram showing an example of a method for detecting coil breakage.

[Explanation of symbols]

2 rotor (magnetic material) 6,8 magnetic material 46,51,52,53,54 Differential amplifier 61, 62, 63, 64 XOR circuit 71, 72, 73, 74 Low-pass filter L1, L2, L3, L4 coil R resistance

Claims (7)

[Claims] 1. A disconnection detecting device for detecting disconnection of a detector including a coil, wherein a resistor having one terminal connected to one terminal of the coil, and a resistor connected to the resistor and / or the other terminal of the coil. A disconnection detecting device comprising: an applying unit that applies an AC signal; and a determining unit that determines a phase relationship between the AC signal and a detection signal output from the one terminal. 2. The applying means applies a first AC signal to the other terminal of the resistor so that the first AC signal and the detection signal output from the one terminal have opposite phases. A second AC signal having a phase opposite to that of the first AC signal is applied to the other terminal of the coil, and the determination means determines whether the first AC signal and the detection signal are in phase. The disconnection detection device according to claim 1, wherein it is configured to determine whether or not the second AC signal and the detection signal have opposite phases. 3. A determination result that is temporarily determined to be in phase due to a change in the first AC signal or the detection signal, or
3. The disconnection detecting device according to claim 2, further comprising means for invalidating a determination result that is temporarily determined to be in a reverse phase due to a change in the second AC signal or the detection signal. 4. A magnetic device comprising a coil and a magnetic body that moves while changing the distance between the coil and the magnetic body, and based on a detection signal output from the coil and changing according to the distance from the magnetic body, A position detecting device for detecting the position of a body, comprising the disconnection detecting device according to claim 1. 5. Means for generating from the detection signal an alternating current signal having a phase difference according to the position of the magnetic body with respect to the phase of the alternating current signal applied to the coil, and the position of the generated alternating current signal. The position detecting device according to claim 4, further comprising: a unit that detects a phase difference; and a unit that obtains a position of the magnetic body based on the detected phase difference. 6. A coil, and a magnetic body that rotates while changing the distance to the coil, and based on a detection signal that is output from the coil and that changes according to the distance to the magnetic body, A rotation angle detection device for detecting a rotation angle of a magnetic body, comprising the disconnection detection device according to claim 1. 7. A means for generating, from the detection signal, an alternating current signal having a phase difference according to the rotation angle of the magnetic body with respect to the phase of the alternating current signal applied to the coil, and the means for generating the alternating current signal. 7. The rotation angle detecting device according to claim 6, further comprising: a unit that detects a phase difference; and a unit that determines a rotation angle of the magnetic body based on the detected phase difference.