JPH0131126B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-resolution electromagnetic induction rotation angle detection device.

Microsin is widely known as an electromagnetic induction type non-contact rotation angle detector. This Microshin has a great advantage over other rotational angle detectors (e.g. potentiometers, synchronous resolvers, etc.) by being non-contact type.
This has the disadvantage that the region where the characteristic of rotation angle versus output voltage is linear is limited to the vicinity of the zero point. In other words, a periodic function signal in the form of a trigonometric function is obtained from Microsyn in response to the rotation angle, but it exhibits extremely non-linear characteristics in the rotation angle region corresponding to the apex of the function. It was difficult to detect the exact rotation angle. Furthermore, there is a limit to the detection resolution that can be obtained in the linear region, and high resolution has not been obtained.

This invention was made in view of the above points,
It is an object of the present invention to provide a rotation angle detection device that can detect rotation angles with good linearity over the entire rotation range and can also detect rotation angles with high resolution. This purpose is to provide a stator comprising a plurality of pairs of magnetic poles wound to produce a differential output, and a rotor facing each magnetic pole of the stator via a suitable gap. This is achieved by providing slot teeth on opposing surfaces of each magnetic pole of the rotor and stator. The slot teeth are provided so that the correspondence between each slot tooth and the slot tooth of the rotor changes differentially as the rotor rotates between the paired magnetic poles, and It is provided so that an appropriate mechanical phase shift occurs between the two. As a result, in a pair of magnetic poles that generate differential output, a differential change of one cycle is realized for each pitch of the slot teeth, and high-resolution angle detection corresponding to the pitch of the slot teeth is realized. can be done. Furthermore, the mechanical phase shift of the slot teeth between each pair of magnetic poles causes a shift in permeance change in each pair of magnetic poles, and based on this, rotation angle detection with good linearity can be performed.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the rotation angle detection device 22 shown in FIG.
Stator 1 has four magnetic poles 1A, 1B, 1, 1
are arranged at approximately 90 degree intervals in the circumferential direction,
Two magnetic poles 1A and 1 or 1B and 1 facing each other in the radial direction form a pair, and the primary winding and the secondary winding 2A, 2B, 2 are arranged so that a differential output can be obtained from each pair. ,2,3A,3B,3
A, 3 are wound around each pole 1A to 1, respectively. A rotor (iron core) 4 is arranged in a space surrounded by each magnetic pole 1A to 1.
A magnetic circuit is formed between the rotor 4 and the rotor 4 through a gap. This rotor 4 rotates together with the shaft 5. Axis 5 has a rotation angle θ to be detected.
is given.

When detecting the rotation angle θ based on the voltage level of the output signal generated in the secondary winding of the detection device 22 (DC voltage level obtained by smoothing the AC component on the primary side), the windings 2A, 2B, 2, A circuit is constructed as shown in FIG. 2 with 2 as a secondary winding and windings 3A, 3B, 3, and 3 as secondary windings. That is, each pole 1A to 1 primary winding 2A, 2B, 2
A, 2 are connected in series so as to generate magnetic flux in the directions of arrows X, Y, . . . at a certain moment in each pole 1A to 1, and an excitation alternating current signal is applied from an oscillator 6. The secondary windings 3A and 3 wound around the pair of magnetic poles 1A and 1 are connected in series with opposite phases, and the difference A- between the voltages A and 3 induced in the respective windings 3A and 3 is applied to the rectifier circuit 7. obtained through. The secondary windings 3B and 3 wound around the other pair of magnetic poles 1B and 1 are also connected in series with opposite phase, and the difference B- between the voltages B induced in the respective windings 3B and 3 is It is obtained via the rectifier circuit 8. In the rectifier circuits 7 and 8, the excitation frequency component is removed by synchronous rectification, and the DC differential output A is
- and B-, respectively.

As shown in FIG. 1, the circumferential side of the rotor 4 is provided with equally spaced slot teeth. This slot tooth consists of a groove 4a and a protrusion 4b. In addition, each magnetic pole 1A, 1B, 1, 1 of the stator 1
The end face of the rotor 4 (the face facing the rotor 4)
Slot teeth (grooves 1a and protrusions 1b) with pitches approximately corresponding to the pitch of the teeth are formed.
Teeth 4a, 4b of rotor 4 and each magnetic pole 1 of stator 1
The correspondence relationship between the teeth 1a and 1b of A to 1 is such that a mechanical phase shift equivalent to 1/2 pitch occurs between pairs of magnetic poles (1A and 1 or 1B and 1). As a result, the permeance between one magnetic pole 1A or 1B and the rotor 4 and the permeance between the other magnetic pole 1 (or 1) and the rotor 4 change differentially, with one tooth pitch being one cycle. Also, each magnetic pole pair (1A and 1
and 1B, 1), a mechanical phase shift of less than 1/2 pitch occurs. In this example, since there are two pairs of magnetic poles (1A, 1 and 1B, 1), the design is such that a mechanical phase shift of 1/4 pitch, which is half of 1/2 pitch, occurs. Mechanical phase shift between this pair of magnetic poles (e.g. 1/4 pitch)
This causes a phase shift in each pair of output signals (A-, B-). The correspondence relationship between the teeth 4a, 4b of the rotor 4 and the teeth 1a, 1b of each magnetic pole 1A to 1 of the stator 1 is expanded and shown in FIG. In addition, although the pitch number of the teeth of the rotor 4 is 9 pitches per rotation in FIG. 3, this is merely an example.

Looking at the pair of stator magnetic poles 1A, 1, the correspondence between the teeth 1a, 1b of each magnetic pole 1A, 1 and the teeth 4a, 4b of the rotor 4 is shifted by 1/2 pitch (1/2 tooth), so When the permeance of the gap between the end (tooth part) of one pole 1A and the rotor 4 (tooth part) is maximum, the other pole 1A
and the permeance of the gap of the rotor 4 becomes minimum. At a rotation angle deviated by 1/4 pitch from that angle, the permeance of each pole 1A, 1 is balanced, and at a rotation angle deviated by 1/2 pitch, the permeance of one pole 1A is minimum and the permeance of the other pole 1 is maximum. Become. In this way, each pole 1A, 1
The permeance of A changes in opposite directions (differentially). The same thing can be said about the other magnetic pole pair 1B,1. However, the magnetic pole meter 1B, 1 is located at a position 90 degrees off from the magnetic pole pair 1A, 1 (pole 1A, 1).
(at half the interval of 180 degrees),
The same change in permeance as seen in the magnetic pole pair 1A, 1 appears at a rotation angle deviated by 1/4 pitch.

Permeance P A , P _B between the rotor 4 and the stator 1 at each magnetic pole 1A, 1B, 1 _, 1,
P ^- _A and P ^- _B are shown in Figure 4. FIG. 4 shows the permeance on the vertical axis and the rotation angle θ of the rotor 4 on the horizontal axis. The angle 2π/N (radian) is the angle corresponding to one pitch of the rotor teeth 4a, 4b, and N corresponds to the number of teeth provided on one circumference of the rotor 4 (9 in the example shown in FIG. 1). The secondary windings 3A, 3B, 3 of the stator magnetic poles 1A to 1 correspond to the rotation angle θ of the rotor 4.
The levels of the voltages A, B, , induced in A, 3, respectively, are determined by the permeances P _A , P _B ,
This corresponds to P ^- _A and P ^- _B. Therefore, as shown in FIG. 5, the differential output A- obtained from the secondary windings 3A, 3 of one magnetic pole pair 1A, 1 becomes a periodic function signal with the rotation angle θ as a variable, and this is expressed as a sine If the wave signal is sinNθ, the other magnetic pole pair 1B,
The differential output B- obtained from the secondary windings 3B and 3 of No. 1 becomes an inverted signal -cosNθ of a cosine function with the rotation angle θ as a variable. In this way, periodic function signals sinNθ and -cosNθ whose phases are shifted by an angle (π/2N radian) corresponding to 1/4 pitch of the teeth formed on the rotor 4 and stator 1 are obtained.

If the parts with good linearity of the rotation angle (θ) vs. signal level characteristics of these two phase-shifted periodic function signals sinNθ and -cosNθ are synthesized in a complementary manner, good linearity can be obtained over the entire rotation range. A rotation angle detection signal can be obtained. An example of a signal processing circuit 10 for this purpose is shown in FIG. Differential output A-=sinNθ obtained from one magnetic pole pair 1A, 1
is defined as A ₁ , and the differential output B-=-cosNθ obtained from the other magnetic pole pair 1B, 1 is defined as B ₁ .

In FIG. 6, the linear region detection circuit 20 is
Two signals A ₁ and B ₁ obtained according to the rotation angle θ
One signal (A ₁ or B ₁ ) producing a level belonging to a region with good linearity of the rotation angle vs. signal level characteristic is detected. The synthesis circuit 21 synthesizes the signals (A ₁ or B ₁ ) detected by the linear region detection circuit 20 to obtain a rotation angle detection signal S with good linearity over the entire rotation range. Linear region detection circuit 20 includes comparators 11 and 12 and gate signal generation logic 13. The signal _A1 generated in accordance with the rotation angle θ as described above is input to comparators 11 and 12, respectively. The signal _B1 is input to the comparator 11, and is inverted by the inverter 17 and sent to the comparator 12.
is input. The comparator 11 is for detecting the intersection of the levels of the signals A ₁ and B ₁ , and its output signal S1 becomes "1" when A ₁ ≦B ₁ . Comparator 12
is for detecting the intersection of the levels of signals A ₁ and ₁ , and when A ₁ ≧ ₁ , the output signal S2 is “1”
becomes. An example of the periodic function signals A ₁ , B ₁ , ₁ corresponding to the rotation angle θ input to the comparators 11 and 12 is shown in FIG. 7a, and the output signals S1 and S2 are shown in FIG. 7b.
Shown below. The gate signal generation logic 13 generates each signal.
Based on the rise and fall of S1 and S2 (that is, the intersection detection timing), the gate signal T _A1 ,
T _A2 , T _B1 , and T _B2 are generated as shown in FIG. 7c. Specifically, each gate signal T _A1 ~ T _B2 is a signal
It becomes "1" when the following logic is established according to the level states of S1 and S2.

T _A1 = S1・S2, T _A2 = 1・2, T _B1 = 1・S2, T _B2 = S1・2, gate signals T _A1 and T _A2 are used in the synthesis circuit 21 to select signal A ₁ . , gate signals T _B1 and T _B2 are used to select signal _B1 . Therefore, based on the gate signals T _A1 , T _A2 , T _B1 , T _B2 generated as shown in Fig. 7 c, Fig. 7 d
As shown in FIG. 2, only the portions with good linearity in the signals A ₁ and B ₁ are selectively combined, and a rotation angle detection signal S〓 with good linearity over the entire rotation range is obtained.

As another embodiment of the signal processing circuit 10, a configuration as shown in FIG. 8 can be adopted. In FIG. 8, the configuration of the linear region detection circuit 20 is as follows.
The gate signals T _A1 , T _A2 , T _B1 , T _B2 corresponding to the linear parts of each signal A ₁ , _{B 1} are generated in the gate signal generation logic 1 as shown in FIG. 9b.
Obtained from 3. In addition to the signals A ₁ and B ₁ obtained according to the rotation angle θ, their inverted signals ₁ (=−sinNθ) and ₁ (=cosNθ) are input to the synthesis circuit 21. The relationship between the levels of these signals A ₁ , B ₁ , ₁ , ₁ and the rotation angle θ is shown in FIG. 9a. In the selection circuit 14 in the synthesis circuit 21, the gate signal
Select signal ₁ by T _A1 , select signal B ₁ by gate signal T _B1 , select signal A ₁ by gate signal T _A2 , and select signal ₁ by gate signal T _B2 .
Select. In this way, the signal S〓'' selectively outputted by the selection circuit 14 is as shown in FIG. 9c.
It is a composite of the linear parts of A ₁ , B ₁ , ₁ , ₁ that have inclinations in the same direction. Another selection circuit 15 is provided within the synthesis circuit 21. Four reference voltages E1, E2, E3, and E4 of different levels are input to this selection circuit 15.
Reference voltage E1 is selected by gate signal T _B1 ,
Reference voltage E2 is selected by gate signal T _A1 ,
Reference voltage E3 is selected by gate signal T _B2 ,
Reference voltage E4 is selected by gate signal T _A2 . The reference voltages E1 to 1 selected by the selection circuit 15
E4 is inputted to the adder circuit 16 and added to the signal Sθ'' selectively synthesized by the selection circuit 14. As a result, the linear portion of the signal _B1 selected by the gate signal _TB1 has a reference voltage E1 is added,
Reference voltage E2 is added to the linear part of signal ₁ selected by gate signal T _A1 , and reference voltage E3 is added to the linear part of signal ₁ selected by gate signal T _B2 . The reference voltage E4 is added to the linear portion of the signal _A1 selected by the gate signal T _A2 . Reference voltage E1
corresponds to the signal level at the intersection of signals A ₁ and B ₁ , E2 is 3 times E1, E3 is 5 times E1, E4 is E1
This is seven times the level. Therefore, as shown in FIG. 9d, the addition circuit 16 obtains a continuously linear rotation angle detection signal S over a predetermined rotation range (in this example, 2π/N corresponding to one tooth pitch). It will be done.

In addition, the linear area detection circuit 2 in FIGS. 6 and 8
0, the linear region is detected based on the detection of the intersection of the signals A ₁ and B ₁ and the intersection of A ₁ and ₁ , but the level of the signals A ₁ and B ₁ is not limited to this. It is also possible to detect the linear region by comparing and detecting whether it is within the level (+E1, -E1). In other words, the level of the intersection of signals A ₁ and B ₁ (+E1, −E1)
can be predicted, so −E1≦A ₁ ≦+E1 or −
The linear region of the signal A ₁ or B ₁ can be detected by comparing and detecting the region satisfying E1≦B ₁ ≦+E1.

By the way, in the above embodiment, only the relative rotation angle within one tooth pitch (2π/N radians) can be detected. However, by separately detecting the coarse absolute rotation angle for each tooth of the rotor 4 by an appropriate means, the coarse absolute rotation angle for each tooth and the fine relative rotation within one pitch determined as described above are calculated. In combination with the angle, the absolute value of the rotation angle θ of the rotor 4 can be determined. FIG. 10 schematically shows one example in a side view, in which two detection devices 22 and 23 are provided on the shaft 5 to which the rotation angle θ is applied. One of the detection devices 22 consists of a stator 1 and a rotor 4, each having slotted teeth 1a, 1b, 4a, 4b, as shown in FIG. It is detected by The other detection device 23 is for roughly detecting the absolute rotation angle of each tooth.
An example of this rough detection device 23 is shown in FIG.
In FIG. 11, a stator 1' has four magnetic poles 1A' to 1' arranged at 90 degree intervals, and each magnetic pole 1A' to 1' has a primary winding and two magnetic poles, as in FIG. The next windings are wound respectively, forming a pair of magnetic poles 1A' and 1.
Although A' or 1B' and 1' are adapted to vary differentially, no slot teeth are provided at the ends of each magnetic pole. The rotor 4' is mounted eccentrically on the shaft 5 and is not provided with slotted teeth. Due to the eccentricity of the rotor 4', each magnetic pole 1
The permeance between A'-1' and the rotor 4' changes at a rate of one cycle per revolution of the rotor 4'. Note that the shape of the rotor 4' is not limited to the eccentric shape shown in the drawings, but may be any shape that causes a change in permeance at a rate of one cycle per rotation. The detection output of the detection device 23 shown in FIG. 11 is processed by a signal processing circuit 10 as shown in FIG. 6 or 8. As a result, the 12th
As shown in Fig. a, a linear angle detection signal S〓' (although the resolution is coarse) is obtained by the detection device 23 over the entire range of one rotation. On the other hand, the detection device 22
As shown in FIG. 12b, the angle detection signal S〓 obtained from the angle detection signal S〓 indicates the relative rotation angle for each tooth pitch with high resolution. Therefore, by combining the detection signals S〓 and S〓' of both the detection devices 22 and 23, the absolute rotation angle can be detected with high resolution.
The detection device 23 outputs a step-shaped detection signal as shown in FIG. 12c corresponding to the position of each tooth.
A device that generates S〓′ (for example, a switch, a combination of various sensors, etc. and a processing circuit) may be used.

In the above embodiment, the rotation angle is detected based on the voltage level of the detection signal.
The rotation angle can also be detected based on the phase shift of the excitation AC signal component appearing on the next side. Examples are shown below.

By using the detection device 22 having exactly the same configuration as in FIG. 1 and changing the winding circuit as shown in FIG. 13, the rotation angle detection device of the present invention can be made into a phase detection type. . In Figure 2, 1
Winding 2A to which an AC signal was applied as the next winding,
2B, 2, 2 is used as a secondary winding in FIG. In addition, in Fig. 2, windings 3A and 3 are used as secondary windings to take out differential outputs, respectively.
A or 3B, 3 is used as the primary winding in FIG. Then, the magnetic pole pairs 1A, 1 and 1B, 1 that cause differential changes are excited with separate alternating current signals that are out of phase. Incidentally, the direction of the magnetic flux excited in each pole 1A, 1, 1B, 1 at a certain moment is as shown by arrows X and Y. One magnetic pole pair 1A,
Appropriate oscillation means 2 is connected to the primary winding 3A, 3 of 1.
A sine wave signal Isinωt is applied from a suitable oscillating means 25, and a cosine wave signal Icosωt is applied to the primary windings 3B, 3 of the other magnetic pole pair 1B, 1.
1 for the stator 1 and rotor 4 as shown in FIG.
Since slot teeth of pitch=2π/N radians are provided, the permeance change between each magnetic pole pair 1A to 1 and the rotor 4 is as shown in FIG. 4 for each pitch, as described above. As is clear from this figure, the permeance change between one magnetic pole pair 1A, 1 excited by the sine wave signal Isinωt and the other magnetic pole pair 1B, 1 excited by the cosine wave signal Icosωt is 1 If there is a /4 pitch shift and one permeance change is expressed by a cosine function cosNθ, the other permeance change can be expressed by a sine function sinNθ. Therefore, each magnetic pole pair 1A, 1 and 1
The combined output E of the voltages induced in the secondary windings 2A, 2, 2B, 2 of B, 1 can be roughly expressed as the following equation.

E=Ksin(ωt−Nθ) …(1) In other words, the phase shift is N times the rotation angle θ of the rotor 4 (N is the number of slot tooth pitches per rotation as described above) with respect to the excitation AC signal sinωt. An alternating current signal in which Nθ occurs can be obtained as an output signal E. K is a constant.

FIG. 14 shows an example of a circuit for detecting the phase shift Nθ from the output signals E of the secondary windings 2A to 2 in FIG. 13. In FIG. 14, the detection device 22 is
In the detection device according to the present invention shown in the figure, the circuit of windings 2A-2, 3A-3 is configured as shown in FIG.

Oscillator 32 generates a high speed clock pulse CP. The frequency dividing circuit 33 divides the frequency of this clock pulse CP by 1/M and outputs a pulse Pb with a duty of 50% and an inverted signal Pa of this pulse Pb (M is an arbitrary integer). Specifically, it includes a 2/M frequency divider 34 and a flip-flop 35 for 1/2 frequency division, and a pulse Pc obtained by dividing the clock pulse CP by 2/M is obtained from the frequency divider 34, and this pulse Pc is sent to the flip-flop 35.
Divide the frequency by 1/2 by 5. As a result, the output (θ) of the flip-flop 35 produces a 50% duty square wave pulse with a frequency of 1/M of the clock pulse CP.
Pb is output, and its inverted output ( ) outputs a square wave pulse Pa, which is the inverted pulse Pb.
Pulses Pb and Pa with a phase shift of 180 degrees are input to flip-flops 36 and 37 for 1/2 frequency division, respectively, and pulses 1/2Pb and 1/2Pa, which are obtained by dividing these pulses Pb and Pa by 1/2, are obtained. can get. Pulse 1/2 output from each flip-flop 36 and 37
Pb and 1/2Pa have a frequency of 1/2M of the clock pulse CP and are 90 degrees out of phase.

Each pulse 1/2Pb and 1/2Pa is input to low-pass filters 38 and 39, respectively, and their fundamental wave components are extracted. Therefore, if the signal output from the low-pass filter 38 is a cosine wave signal cosωt, the signal output from the low-pass filter 39 is a sine wave signal sinωt. low pass filter 3
The output cosωt of 8 is amplified by the amplifier 40, and the output Icosωt is applied to one excitation pole pair 1B and the primary windings 3B and 3 of 1. The output sinωt of the low-pass filter 39 is amplified by the amplifier 41, and the output Isinωt of the other excitation pole pair 1A and 1 is
Applied to the next windings 3A and 3.

As described above, an alternating current signal E=Ksin(ωt−Nθ) with a phase shift Nθ corresponding to the rotation angle θ is obtained from the output windings 2A to 2. This output signal E is input to the polarity determination circuit 26 via the amplifier 42. The other polarity determining circuit 27 is supplied with one excitation AC signal Isinωt from the amplifier 24. The polarity determination circuits 26 and 27 output "1" when the amplitude of the input signal has positive polarity, and output "0" when the amplitude of the input signal has negative polarity. Each polarity discrimination circuit 26 and 27
The outputs of are input to rise detection circuits 28 and 29, respectively. The rise detection circuits 28 and 29 are monostable multivibrators, and output one short pulse when the input signal rises to "1". Therefore,
As shown in FIG. 15, the rotation angle detection signal E=
When the phase angle (ωt-Nθ) of Ksin (ωt-Nθ) is 0 degrees, a rising edge detection pulse Ts is sent from the rising edge detection circuit 28.
is output, and when the phase angle ωt of the excitation AC signal Isinωt is 0 degrees, the rise detection circuit 29 outputs a rise detection pulse To. Rotation angle detection signal E=
Ksin(ωt−Nθ) lags behind the excitation AC signal Isinωt by a phase angle Nθ corresponding to N times the rotation angle θ. Therefore, the rising edge detection pulse Ts is generated after a time delay corresponding to the phase shift Nθ from the generation of the rising edge detection pulse To.

Using the counter 30, the rising edge detection pulse
Data corresponding to the phase shift Nθ can be obtained by counting the time difference between To and Ts. The oscillator 15 is connected to the count input of the counter 30.
A clock pulse CP oscillated from is given.
The excitation AC signals Isinωt and Icosωt have a frequency of 1/2M of this clock pulse CP.

The reset input of the counter 30 is an excitation AC signal.
A pulse To indicating the 0 phase of Isinωt is given.
Therefore, the counter 30 is reset every 0 phase of the excitation AC signal Isinωt.

The output of the counter 30 is input to a buffer register 31. The rotation angle detection signal Ksin(ωt−
Pulse Ts indicating 0 phase (ωt−Nθ=0) of Nθ)
is given. When this pulse Ts is generated, the count contents of the counter 30 are taken into the buffer register 31. Therefore, the buffer register 31 receives a count value corresponding to the phase shift Nθ. In this way, the register 31 outputs data D〓 indicating a phase shift Nθ that is expanded to N times the actual rotation angle θ. Therefore, rotation angle detection can be performed with high resolution.

By the way, as mentioned above, the data D〓 in the register 31 indicates the relative rotation angle within one pitch of the teeth with high resolution. Preferably, a detection device 23 for detecting the angle is provided in parallel. The detection device 23 can have the same structure as that shown in FIG. 11, but in order to make it a phase detection type, the circuit configuration of the stator winding is made as shown in FIG. 13. In that case, the output signal E' of the detection device 23 is
Ksin(ωt−θ), and a phase shift corresponding to the rotation angle θ occurs. The output signal of this detection device 23
Data corresponding to phase shift θ based on E′
To obtain D〓', the same processing as in FIG. 14 may be performed. In this way, the relationship between the relative rotation angle detection data D〓 by the high-resolution detection device 22 and the absolute rotation angle detection data Dθ' by the low-resolution detection device 23 is determined by the signal S shown in FIGS. 12b and 12a. 〓、
It is similar to S〓' (however, the vertical axis in the figure is a level, but in this case it is a phase shift), and by combining the two, the absolute rotation angle can be detected with high resolution. .

Note that the shapes of the stator 1 and rotor 4 are not limited to those shown in FIG. 1, and can be modified as desired without departing from the gist of the invention. For example, the direction of magnetic flux passing through the gap between the stator 1 and rotor 4 is in the radial direction in FIG.
As shown in FIG. 16, the design can be changed so that it is in the axial direction. In FIG. 16, the rotor 43 is formed with slotted teeth of a constant pitch, similar to the rotor 4 in FIG. The stator 44 is
Four magnetic poles 44A, 44B, 44, 4 on the circumference
4, each of the magnetic poles 44A to 44 protrudes in the axial direction, and slot teeth are formed on the end face facing the slot teeth of the rotor 43, respectively. Furthermore, a magnetic pole 44C protrudes in the axial direction from the center of the stator 44. When detecting the rotation angle based on the level of the detection signal, the magnetic poles 44A to 44
The windings 45A to 45 are used as secondary windings, and the differential output between the windings 45A and 45 is taken out, as well as the differential output between the windings 45B and 45. At this time, the winding 45C of the central magnetic pole 44C is the primary winding. When detecting the rotation angle based on the phase shift of the detection signal, contrary to the above, windings 45A and 45
Let A be a pair of primary windings, 45B and 45 be another pair of primary windings, and winding 45C be a secondary winding.

In addition, in FIG. 1, the magnetic poles 1A and 1 of the stator 1 are located on the same circumference, but as shown in FIG. Arranged slightly off-center,
It is also possible to lengthen the rotor 4 by that much. In FIG. 17, a rotor 46 is slightly longer than the rotor 4 in FIG. 1 in the axial direction.
The stator 47 has a pair of differentially changing magnetic poles 1A, 1
The other stator 48 has only another pair of differentially varying magnetic poles 1B, 1. These stators 47 and 48 are arranged side by side in the axial direction such that the magnetic pole pairs 1A, 1 and 1B, 1 are offset by 90 degrees in the circumferential direction. It is assumed that the windings 2A-2, 3A-3 wound around each magnetic pole 1A, 1, 1B, 1 have a circuit configuration exactly the same as that in FIG. 2 or FIG. 13.

Further, the number of differentially changing magnetic pole pairs is not limited to two pairs, and may be further increased. Furthermore, in the above embodiment,
Although the two magnetic poles forming a pair are arranged to face each other in the radial direction (at an interval of 180 degrees), the present invention is not limited thereto.

Further, as shown in FIGS. 18 and 19, the circumferential arrangement relationship of each magnetic pole pair 1A, 1 and 1B, 1 is the same, and the rotor 4 corresponding to each
Even if a mechanical phase shift of 1/4 pitch is caused in the slot teeth A and 4B, the same effects as in each of the above embodiments can be obtained. FIG. 18 shows E-shaped stators 50, 51 arranged facing each other in the radial direction, each of the magnetic poles 1A to 1 having only one winding, and the central magnetic poles 50C, 51
C plays the same role as the magnetic pole 44C in FIG.
Figure 19 shows a pair of magnetic poles 1A, 1 and 1B, 1.
Circular stators 47 and 48, each having B, are arranged without shifting their angles, and since there is a mechanical phase shift of 1/4 pitch between the slot teeth of rotors 4A and 4B, it is substantially the same as in Fig. 17. works similarly. In both Figures 18 and 19, the winding circuit configuration is as shown in Figure 2 (voltage level detection type) or Figure 13.
Either of the types shown in the figure (phase shift detection type) can be applied.

In addition, the windings 2A to 2, 3 in FIGS. 2 and 13
A to 3 do not necessarily have to be connected in series as shown in the figure; in the case of the primary winding, a predetermined AC signal is applied to each winding independently, and the secondary Of course, in the case of windings, the outputs of each winding may be extracted individually and then added or subtracted. Further, the grooves 1a and 4a of the slot teeth do not necessarily have to be concave spaces, but may be filled with an appropriate non-magnetic material.

As explained above, according to the present invention, the provision of slot teeth in the stator and rotor provides an excellent effect in that the rotational angle detection resolution is dramatically improved. In other words, in the case of the voltage level detection type, the detection signal corresponding to the rotation angle θ is obtained as a periodic function signal (sinNθ) whose cycle is an angle (2π/N) corresponding to one pitch of the slot tooth. Compared to the case where the rotation angle θ is detected as a periodic function signal (sin θ) of one cycle per rotation (2π), the detection resolution is N times higher (N is the number of tooth pitches for one rotation of the rotor). Also, in the case of the phase shift detection type, the phase shift corresponding to the rotation angle θ is
Since it becomes Nθ, the resolution becomes N times. Moreover, the mechanical phase shift of the slot teeth between each pair of magnetic poles has the effect that rotation angle detection with good linearity can be performed. In other words, in the voltage level detection type, a periodic function signal (sinNθ, −cosNθ) whose phase is shifted from each magnetic pole pair
Since both linear regions can be detected simultaneously, rotation angle detection with good linearity can be performed over the entire rotation range by complementarily composing the linear regions of the two. In addition, in the phase shift detection type, by exciting each magnetic pole pair with an alternating current signal with a phase shift, the phase shift of this excitation signal is compensated for by the shift in permeance change between the magnetic pole pairs due to the shift of the slot teeth. Since the AC signal (sin(ωt−Nθ)) with a phase shift corresponding to the rotation angle is obtained by the action, completely linear rotation angle detection can be performed (the phase shift of the AC signal and the rotation angle are since the relationship is perfectly linear).

[Brief explanation of drawings]

Figure 1a is a radial sectional view showing an embodiment of the present invention, Figure 1b is an axial sectional view of the same embodiment, and Figure 2 is a circuit of the windings wound around the stator poles of the same embodiment. A circuit diagram showing a configuration example, FIG. 3 is an exploded view illustrating the relationship between the teeth formed on the rotor and each stator magnetic pole in the same embodiment, and FIG. 4 shows the rotor and each stator in the same embodiment. FIG. 5 is a graph showing the permeance between the stator magnetic poles and the rotation angle θ on the horizontal axis. Figure 6 is a graph showing the differential output signals of the two output signals shown in Figure 5, and is a signal for complementary synthesis of the linear regions of the two output signals shown in Figure 5 to obtain a linear rotation angle detection signal over the entire rotation range. A block diagram showing an example of the processing circuit, FIG. 7 is a graph explaining the operation of the circuit shown in FIG. 6, FIG. 8 is a block diagram showing another example of the signal processing circuit shown in FIG. 6, and FIG. Figure 10 is a graph explaining the circuit operation shown in Figure 1, and a detection device for detecting the absolute rotation angle of each slot tooth of the rotor on the same rotation axis as the high-resolution rotation angle detection device shown in Figure 1. 11 is a front sectional view showing an example of a detection device for detecting the absolute rotation angle of each slot tooth used in FIG. 10, and FIG. 12 is a side view schematically showing an example of a combination of A graph showing an example of a detection signal by each detection device in the figure,
FIG. 13 is a circuit diagram showing another circuit configuration example of the stator magnetic pole winding in the embodiment shown in FIG. 1, and FIG. 14 is an example of a signal processing circuit when the winding circuit configuration shown in FIG. 13 is adopted. 15 is a timing chart explaining the phase shift detection operation in FIG. 14, FIG. 16 is an exploded perspective view showing another embodiment of the present invention, and FIG. 17a is a diagram showing still another embodiment of the present invention. FIG. 18b is a sectional view taken along line bb in FIG. 18a, FIG. 18a is a schematic side view showing another embodiment of the present invention, and FIG. , FIG. 19a is an axial sectional view showing still another embodiment of the present invention, and FIG. 19b is a sectional view taken along line bb in FIG. 19a. 1, 1', 44, 47, 48, 50, 51...
Stator (iron core), 1A, 1B, 1, 1, 1
A', 1B', 1', 1', 44A~44...
Magnetic pole, 2A to 2,3A to 3,45A to 45...Winding, 4,43,46,4A,4B...
... Rotor (iron core), 5 ... Rotating shaft, 6 ... Oscillator,
7, 8... Rectifier circuit, 1a... Groove of stator slot tooth, 1b... Projection of stator slot tooth, 4a... Groove of rotor slot tooth, 4b
... Protrusion of rotor slot tooth, 22 ... High-resolution rotation angle detection device according to the present invention, 23
...A detection device for detecting the absolute rotation angle of each slot tooth with coarse resolution.

Claims (1)

[Claims] 1. A rotor comprising a stator having a plurality of pairs of differentially wound magnetic poles, and a rotor facing each magnetic pole of the stator through an appropriate gap. In the angle detection device, the rotor has N pitches of teeth per rotation, and the stator includes a primary winding means wound around each magnetic pole, and a secondary winding means magnetically coupled to the primary winding means. winding means, and further provided with teeth corresponding to the teeth of the rotor at the end of each magnetic pole, so as to produce one cycle of reluctance change corresponding to one pitch of the rotor teeth, The correspondence relationship between each rotor tooth and stator tooth is shifted by 1/n pitch between adjacent magnetic poles so that the cycle of reluctance change is shifted by 1/n pitch between adjacent magnetic poles, and generates a plurality of reference alternating current signals that are out of phase with each other, and excites each primary winding means of each of the magnetic poles with the reference alternating current signals that are out of phase between adjacent magnetic poles; an excitation means for outputting an AC signal having an electrical phase shift corresponding to a rotation angle from the secondary winding means, and a difference between the output AC signal of the secondary winding means and the reference AC signal A rotation angle detection device comprising a phase shift measuring means for measuring an electrical phase shift with respect to one rotor and outputting the phase shift measurement data as absolute rotational position data within 1/N rotation of the rotor. 2. In the rotation angle detection device according to claim 1, the teeth are provided so that the correspondence relationship between each tooth and the rotor tooth is shifted by 1/2 pitch between the pairs of magnetic poles, and Here, a rotation angle detection device is provided with the teeth so that an appropriate deviation of less than 1/2 pitch occurs. 3. In the rotation angle detection device according to claim 1, the stator includes two pairs of magnetic poles arranged at an interval of approximately 90 degrees in the circumferential direction,
The teeth are provided so that the correspondence relationship between each tooth and the rotor tooth is shifted by 1/2 pitch between a pair of magnetic poles, and the teeth are provided so that a shift of 1/4 pitch occurs between each pair of magnetic poles. Rotation angle detection device. 4. A stator comprising a plurality of pairs of differentially wound magnetic poles, and a rotor facing each magnetic pole of the stator via an appropriate gap,
A first detection device comprising slot teeth provided on opposing surfaces of each magnetic pole of the rotor and the stator, and a second detection device configured to detect an absolute rotation angle of at least each tooth in the rotor, In the first detection device, the rotor has N pitches of teeth per rotation, and the stator has a primary winding means wound around each magnetic pole, and the stator is magnetically coupled to the primary winding means. Further, teeth corresponding to the teeth of the rotor are provided at the end of each magnetic pole, so that a reluctance change of one cycle is produced corresponding to one pitch of the rotor teeth. In addition, the correspondence between each rotor tooth and the stator tooth is shifted by 1/n pitch between adjacent magnetic poles so that the cycle of reluctance change is shifted by 1/n pitch between adjacent magnetic poles. generating a plurality of reference alternating current signals having a frequency shifted from each other in phase, and respectively exciting each primary winding means of each of the magnetic poles with the reference alternating current signals having a phase shift between adjacent magnetic poles; and excitation means for outputting an AC signal having an electrical phase shift corresponding to the rotation angle of the rotor from the secondary winding means, and an output AC signal of the secondary winding means and the reference. comprising phase shift measuring means for measuring an electrical phase shift with one of the alternating current signals and outputting the phase shift measurement data as absolute rotational position data within 1/N rotation of the rotor; A rotation angle detection device that detects an absolute rotation angle over a wide range and with high resolution by combining the outputs of a second detection device and a second detection device. 5. The second detection device includes a second stator that includes a plurality of pairs of differentially wound magnetic poles, and a second stator that connects each magnetic pole of the second stator via an appropriate gap. It includes a second rotor that faces the rotor of the first detection device and rotates as one body, and the second rotor applies a permeance change of one cycle per rotation to each magnetic pole of the second stator. 5. The rotation angle detection device according to claim 4, wherein the rotation angle detection device has a shape that generates a rotation angle.