JPH0591706A - Electromagnetic rotating machine - Google Patents

Abstract

PURPOSE:To obtain an electromagnetic rotating machine of a low cost and a small size, by generating two kinds of pulses every one revolution of the rotor of the electromagnetic rotating machine, and by generating an absolute positional signal based on the synchronism of the phase difference between the two kinds of pulses. CONSTITUTION:When a rotor yoke 4 is rotated once, binary signals are generated using a comparator from the magnetization number of driving magnets 1 and the counter electromotive forces of coils 10w, and the binary signals are used as first pulses. Also, the signals determined by the magnetization number of FG magnets 2 and the number of the generator line elements of generator line element part 7a are used as second pulses. The greatest common divisor of the pulse numbers of these two kinds of pulses is set 1 (i.e., prime number mutually). When the phases of these two signals coincide with each other, an index signal is generated, and thereby, a signal for indicating the rotational position of the rotor yoke 4 is obtained. That is, the conventional element for sensing the driving timing of an electromagnetic rotating machine and the conventional magnet for sensing the rotational position of the rotating machine are made unnecessary. Thereby, the size of the rotating machine can be reduced and the problem relative to leakage magnetic fluxes is eliminated too.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic rotary machine such as a motor used in, for example, a floppy disk drive device, and more particularly to an improvement of its rotational position (index position) detecting method.

[0002]

2. Description of the Related Art Conventionally, as a motor rotational position detecting device, a magnet is provided at a predetermined position of a rotating body of a motor,
Further, at a fixed position facing the magnet on the stator side, a pulse signal is obtained by using a magnetic detection element such as a Hall element that detects a magnetic change of the magnet,
A rotation position detection device that detects a rotation phase is known.

A conventional motor configuration will be described with reference to the drawings. FIG. 15 is a fragmentary plan view of a conventional three-phase brushless motor, and FIG. 16 is a sectional view taken along line XX of FIG. In such a conventional brushless motor, four magnetic circuits, namely, a magnetic circuit for generating a rotational driving force, a magnetic circuit for generating an FG signal, a magnetic circuit for generating a rotational position signal, and a rotating magnetic field are provided. A magnetic circuit is formed to detect the excitation timing for generation.

First, referring to FIG. 16, a schematic structure of a three-phase brushless motor will be described. The substrate 7 is made of a magnetic material such as iron. Hall element 14
Are installed. The rotary shaft 5 is integrally provided with the rotor yoke 4 via the shaft fixing member 6, and is further fitted to the inner race of the bearing 8 provided above the oil-impregnated bearing 9 and the oil-impregnated bearing 9. The integrated body including the rotor yoke 4, the drive magnet 1, the FG magnet 2, the position detecting magnet 13 and the like freely rotates with respect to the substrate 7.

Next, the drive magnet 1 (FIG. 15) is fixed inside the outer edge of the rotor yoke, and as is well known, the rotor yoke 4 is rotationally driven by applying a rotating magnetic field to the drive magnet 1. Let it be done. For this reason, as shown in FIG. 15, the drive magnet 1 is multi-polarized with 16 poles in the radial direction, and is fixed inside the outer edge portion of the rotor yoke.

To actuate a rotating magnetic field, a plurality of drive coils 10 are provided wound around a stator yoke 11, while the stator yoke 11 is used to rotate the rotating shaft 5.
A plurality of drive coils are radially formed around and the plurality of drive coils are provided on the yoke 11 in the circumferential direction. The stator yoke 11 is fixed on the iron substrate 7 by a fixing member such as a screw (not shown).

In the above structure, the stator yoke 11
Together with the drive magnet 1, the rotor yoke 4, and the drive magnet yoke 3 form a closed magnetic circuit.
A brushless motor of the type in which the drive magnet 1 is provided in the radial direction of the stator yoke 11 so as to be separated from the yoke 11 is referred to as a circumferentially opposed motor. A notch 4h is formed on the outer peripheral surface of the rotor yoke 4,
A position detecting magnet 13, which is a rotational phase detecting means, is embedded in the cutout portion 4h. This magnet 1
3 also constitutes one magnetic circuit.

Further, a plurality of Hall elements 12a, 12b, 1 for detecting the excitation timing of the coil 10 of each phase.
2c is fixed to an appropriate position on the substrate 7. The magnetic field from the drive magnet 1 is applied to these Hall elements 12a, 1
2b, 12c, so these elements 12a, 12
b and 12c detect the change in the magnetic field from the magnet 1, and the magnetic field to be generated by the coil 10 of the stator 11
The phase difference with respect to the magnetic field of the rotating drive magnet 1 is detected, and a current is passed through each phase of the drive coil at an appropriate timing to generate a rotating magnetic field. This rotating magnetic field causes the rotor 4 to rotate in the direction of arrow A in FIG.

On the other hand, the FG magnet 2 is fixed to the outermost peripheral edge portion of the rotor yoke 4, and is magnetized for 120 poles in total. On the surface portion of the iron substrate 7 facing the FG magnet 2, 120 power generating line elements 7a having a pattern as shown in FIG. 3 are formed by etching with a copper pattern or the like. With the above configuration, when the rotor yoke 4 is started to rotate, a sine wave having a frequency corresponding to the rotation speed of the rotor yoke 4 is generated from the power generating line element 7a, so a constant speed rotation control is performed by a control circuit (not shown). ..

When the rotor yoke 4 rotates, the magnet 13 fixed to the rotor yoke 4 also rotates integrally. Therefore, the index position detecting Hall element 14 senses a change in the magnetic field of the magnet 13 and the rotor yoke 4 rotates once. On the other hand, one pulsed so-called position detection signal is generated. With this pulse signal, the rotation phase of the rotating body can be detected. Hall element 14 for position detection that generates a position detection signal
Outputs a waveform as shown in FIG. This waveform signal is input to the comparator 15 shown in FIG. 19 to obtain the position detection signal shown in the lower part of FIG.

[0011]

However, the above-described conventional rotational position detecting method has the following problems. That is, (1) the rotational position detecting magnet 13 is attached to the outermost peripheral surface of the rotor yoke 4, and the magnetic circuit formed by this magnet is open, so that the magnetic flux leaks as a leakage magnetic flux. Therefore, when this motor is used for rotating the disk of the magnetic recording / reproducing apparatus,
Since the leakage magnetic flux enters the magnetic head for magnetic recording / reproduction, it may interfere with accurate recording / reproduction of information.

(2) A space for providing the hall element 14 and the magnet 13 for detecting the rotational position is required, which hinders the downsizing and thinning of the multi-phase brushless motor, and further increases the product cost. is there. Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to prevent various problems due to magnetic flux leakage, and to reduce the number of constituent parts to be low. We propose a compact / thin electromagnetic field converter at low cost.

[0013]

In order to solve the above-mentioned problems and to achieve the object, a rotational position detecting device according to the present invention uses a signal indicating the absolute rotational position of a rotor part with respect to a stator part for one revolution. An electromagnetic rotating machine that rotates while generating m pieces in the meantime, and when the drive magnet rotates in synchronization with the rotor, the counter electromotive voltage generated in the rotating magnetic field generating means is detected to make P1 (natural number) for one rotation of the rotor. The first pulse generating means for generating the equal-interval pulse signals FG1 and the magnetic body for generating a magnetic field rotating in synchronization with the rotation of the rotor are provided, and the magnetic field change generated by the magnetic body by one rotation of the rotor. Based on the periodicity of the phase difference between the generated pulse signals FG1 and FG2 and the second pulse generating means for generating P2 (natural number) pulse signals FG2 at equal intervals in one rotation of the rotor. , The drive magnet and the magnetic body for generating a magnetic field rotating in synchronization with the rotation of the rotor are provided with circuit means for generating a signal indicating an absolute rotational position, and the pulse number P1, P1 of the signals FG1, FG2 Both P2 are set to be natural numbers with m as the greatest common divisor.

[0014]

In the above structure, the numbers of pulses generated in the signals FG1 and FG2 are P1 and P2, respectively, and the greatest common divisor thereof is m, so P1 / m and P2 / m are relatively prime. Therefore, the phases of the signals FG1 and FG2 are restored each time P1 / m and P2 / m pulses are generated.
The timing at which this phase returns to its original value is taken as the generation timing of the position detection signal. For this reason, since the conventional rotary magnet for exclusive use of the index and the rotary position detecting element can be omitted, the electromagnetic rotary machine itself can be made smaller and thinner, and the magnetic flux leakage can be prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.
A spindle motor having a rotational position detecting device, which is suitable for a circumferentially-opposed type spindle motor and a surface-opposed type spindle motor, will be described with three examples. In the first two examples,
Although they are common in that they generate two pulse signals, there is a difference in the processing method of the two pulse signals that are generated. The third embodiment is an example in which the present invention is applied to a surface-opposing spindle motor.

As can be seen from FIGS. 1 and 2, in this embodiment, in order to generate the index signal from the counter electromotive voltage of the coil and the signal from the power generating line element 7a, the conventional drive timing detecting element 12 (FIG. 15) is used. ), Position detection magnet 1
3. Similarly, the Hall element 14 and the like are unnecessary. For this reason, the motor of the embodiment is considerably miniaturized, as will be apparent by comparing the sizes of the conventional example of FIGS. 15 and 16 with the embodiment of FIGS. Below, a configuration for generating two pulse signals that enables downsizing of the motor will be described.

(Description of Principle of Generation of First Pulse Signal FG1) The first pulse signal FG1 will be described with reference to FIGS.
The principle of generation will be explained. 1 and 2 are a plan view and a cross-sectional view of a rotor and a stator portion of the circumferentially opposed motor of the embodiment, respectively. In FIGS. 1 and 2, the parts already described with reference to FIGS. 15 and 16 are designated by the same reference numerals and the description thereof will be omitted.

As is apparent from FIGS. 1 and 2, in this embodiment, the Hall element for detecting the drive timing of the coil is not provided, and the excitation timing is detected from the counter electromotive voltage of the coil. Although this method has already been performed for some motors, the first pulse signal FG1 has not yet been generated using only one phase of the back electromotive force corresponding to each phase. It is new.

Next, the principle of generating the first pulse signal FG1 will be described. FIG. 3 shows a block diagram of a circuit for detecting the counter electromotive voltage of the coil. Coil 10U, 10V, 10W is Y
They are type-wired, and the other end is controlled by the excitation timing switching circuit 18 so as to be connected to either the power supply voltage, the ground, or the open by SW1 to SW6. Here, SW1 to SW6 correspond to the sink transistor or the source transistor of the output circuit.

FIG. 4 shows the energization mode of the coil. In this figure, the horizontal axis indicates time, the vertical axis positive direction indicates that the source transistor is on (SW2, 4, 6 are on) and the zero point is open. The energization method is a method generally called 120-degree energization, and there is a case (open) in which the energization is not performed for each 60 degrees in the electrical angle, and this time is the timing for detecting the counter electromotive voltage of the coil.

FIG. 5 shows the voltage waveform at the coil terminal. This is because the back electromotive force comparators 16U, V,
This is a signal input to W. In FIG. 5, the sine wave component is the counter electromotive voltage, which is binarized by the comparators 16U, V, and W. In this embodiment, the binarized signal of the counter electromotive voltage of the W-phase coil 10W is used as the first pulse signal FG1. As shown in FIG. 3, the outputs of the comparators 16U, V, W are input to the excitation timing switching circuit 18 to combine the excitation timing signals. The coil is energized and controlled by the excitation timing signal to rotate the motor.

(Description of Principle of Generation of Second Pulse Signal FG2) On the other hand, as the second pulse signal, the power generation line element 7a described in the conventional example is used.
A signal obtained by binarizing the signal from is used by the comparator 17. This signal is also input to a speed control circuit (not shown) and used to control the motor at a constant speed. The outputs of the comparators 16 and 17 are the rotational position detection circuit 100.
The rotation position detection circuit 100 outputs a rotation position signal. Therefore, the operating principle of the rotational position detection circuit 100 will be described below.

When the rotor yoke 4 makes one revolution, the counter electromotive voltage of the coil 10W and the number of pulses generated by the comparator 16W are P1, and the number of pulses generated by the line element 7a and the comparator 17 is P2. The magnetizing number of the drive magnet 4 is P
1. The number of line elements of the line element 7a and the magnetization number of the FG magnet 2 are P
2. The greatest common divisor of pulse numbers P1 and P2 is 1
(That is, they are relatively prime). In a normal motor, a rotation position signal as an index signal is generated once per rotation, which is generated by two output signals (FG) from the comparators 16W and 17 as will be described later.
This is because the rotational position detection circuit 100 is configured so as to generate the index signal when the phases of (1, 1 and FG2) match.

Here, the above-mentioned relationship between the numbers of pulses P1 and P2 is generally expanded as follows. That is, the rotation position signal is m for one rotation of the motor (m is a natural number).
In order to generate the signal twice, it is sufficient that the two signals (FG1, FG2) have m phases. That is, P1 = m · k1 (1) P2 = m · k2 (2) holds between the pulse numbers P1 and P2. However, k1 and k2 are natural numbers. In the equations (1) and (2), the pulse signal FG1 is k1.
When the number of FG2 generated is k2 and the number of FG2 generated is k2, the first FG1
And FG2 phase match (the phase difference returns to the original), and k1 pulse signals FG1 are generated, and FG2 is further k2.
This means that the second phase matching occurs when the pulse signals FG1 are generated, the m · k1 pulse signals FG1 are generated, and the m-th phase matching is generated when the m · k2 FG2 signals are generated.
That is, if m is the greatest common divisor of P1 and P2, the rotational position progress will occur only m times.

In the above equations (1) and (2), k1, k
If 2 is relatively prime, the position detection signal is not generated because the phases do not match until 1 and 2 FG1 and FG2 signals are generated. That is, the necessary and sufficient condition for the rotational position signal to be generated m times during one rotation of the disk is that the greatest common divisor of P1 and P2 is m. In particular, when m = 1, P1 and P2 are relatively prime. As described above, the index signal as the rotational position signal is generated once per rotation in a normal motor.

The above is the principle of the present embodiment, and based on this principle, how to process the signals FG1 and FG2 to obtain the rotational position signal will be described below with reference to two embodiments. However, in the two embodiments relating to the generation of the rotational position signal described below, the index signal which is most widely used as the rotational position signal, that is, one index per rotation is used.
When the rotational position signal is generated only once, in other words, P1
Only the case where and P2 are in a prime relationship will be described.

(Description of the First Embodiment) FIG. 10 is a specific circuit diagram of the detection circuit 100, and this circuit 100 comprises a D latch 101. The FG1 signal is input to the clock input terminal of the latch 101, and the FG2 signal is input to the data input terminal. It is desirable that the duty ratio of the data input signal be 1: 1. The output of this latch circuit is the rotational position signal.

The simplest example in which P1 and P2 are relatively prime is when P2 = P1 ± 1 (3) holds, and generalizing this, P2 = P1n ± 1 ( (n is an integer) (4) is satisfied.

As shown in FIG. 1, the FG1 signal generates eight pulses (ppr, pulse pervolution) per revolution of the rotor yoke, corresponding to the number of magnetizations of the drive magnet 4. Further, FG2 is 65 shots corresponding to the magnetized number of the FG magnet 2 and the power generation line element number of the power generation line element portion 7a. FIG. 6 shows FG1 and FG input to and output from the circuit diagram of FIG. 7 when P1 = 8, P2 = 65 and n = 8 are set.
2, the waveform of the position detection signal is shown. In the case of setting as described above, the phase of FG1 with respect to FG2 is gradually delayed by 45 degrees when one cycle of FG2 is 360 degrees as shown in FIG. Therefore, as shown in FIG.
And FG2 are in a relationship of setting the latch 101 at the time of T1, the latch 10 is turned at the counter rotation (T5, 5th).
1 is reset, and is reset again at the first rotation (T9, 9th shot). Thus, the latch 101 repeats set / reset for each rotation.

As is well known, the output of the latch circuit 101 may operate when the time difference between the clock input signal and the data input signal is small. Therefore, in the present embodiment, as shown in FIGS. 1 and 8, in order to prevent malfunction of the D latch 101, the phase difference between the FG1 and FG2 signals at time T1 is about 22.5 degrees (= 360 ÷ (2 × 8)). FIG. 8 shows the phase relationship between the data input and the clock input. The number T attached to the clock
X is the order of clocks counted from T1. As one clock is input, the phase input to the clock data increases by 45 degrees. Therefore, the above D latch 1
The Q output of 01 is inverted at the fifth and ninth clock inputs, and one pulse is generated for one rotation as shown in FIG.

Displacement between coil position and generator line element, deviation of FG magnetizing pulse and dispersion of magnetizing intensity, comparator 16
Depending on the offset voltage of W and 17, FG1 and FG
The duty ratio of the two signals may change, the timings of the clock and data may change, and this may cause a latch miss. In order to prevent this, the clock phase of the D-latch 101 is such that one cycle of the data input waveform is 360 degrees with respect to the rising or falling of the data input of the D-latch 101, and when the rotor yoke makes one rotation,
About 360 / (2 · P1) degrees apart,
The positions of the stator yoke 11 (or the drive coil 10) and the power generation line element 7a, and the phase relationship of the magnetization patterns of the drive magnet 4 and the FG magnet 2 are set.

In the example of FIGS. 1 to 8, when explained with reference to FIG. 1, when the position in the circumferential direction when connecting by a straight line passing through the center of the magnetized pole 11 of the drive magnet 4 and the center of rotation is θ0, the FG magnet. The center of the second magnetic pole 21 also coincides with θ0. Since FG1 is generated from the W-phase coil 10W, focusing on the W-phase coil, the W-phase coil 10W is shown in FIG.
The projections of the stator 11 are attached to the positions shown in FIG. W-phase coil symmetry line (stator protrusion 11
The center line of W) θi is equidistant from the two power generating line elements (7a1, 7a2, shown by broken lines in FIG. 6) closest to θi. That is, it penetrates in the radial direction exactly in the middle between the power generation line elements.

Using the circuit of FIG. 3 set as described above, when θ0 coincides with θi, FG1 simultaneously produces a falling edge and FG2 simultaneously produces a rising edge. Next, when θr (the center line of the magnetic pole adjacent to the magnetic pole 21) passes θI is the timing T1 shown in FIGS. 6 and 8. The phase difference between the rising edges of the FG1 and FG2 signals is the smallest at the timing T1.
If one cycle of 2 is 360 degrees, it is roughly 22.5 (36
0 ÷ (8 × 2)). With the above settings,
Since the FG1 and FG2 signals as shown in FIG. 6 are generated and the phase difference between the data input edge of the D-latch 101 and the clock can be set as far as possible, malfunction can be prevented.

(Explanation of the Second Embodiment) In this second embodiment as well, the relationship between the numbers of pulses of P1 and P2 is relatively prime as in the first embodiment, but P2 = P1 × ( n + 0.5) ± 1 (5) FIG. 9 shows P1 and P2 in the second embodiment.
In equation (5) representing the relationship of P1 = 8. P2 = 6
The relationship between FG1 and FG2 when 1 and n = 7 is shown. FG
The number of 1 is 8 pulses per rotation of the rotor yoke 4. F
G2 has 61 shots.

FIG. 10 shows the structure of the detection circuit 100 of the second embodiment. As shown in the figure, FG1 is a clock input of the D latch circuit 101 and a 1-bit shift register 102.
FG2 is connected to the data input of the D latch circuit 101. The latch 101 is assumed to latch at the rising edge of the FG1 signal as a clock.
The Q output of the D latch circuit 101 is input to the data input of the 1-bit shift register 102 and the ANS 103, and AND1
Reference numeral 03 is a logical product of the Q output of the D latch circuit 101 and the output of the 1-bit shift register 102Q to form a rotation position signal. The capacitor 104 is for removing a glitch (whisker) generated due to a timing difference between the output of the D latch Q and the output timing of the 1-bit shift register Q.

The lower part of FIG. 9 is a timing chart for explaining the operation of the latch 101, shift register 102, and AND gate 103. FIG. 11 shows the phase relationship between the data input and the clock. Number TX attached to the clock
Is the order of clocks counted from T1. Clock is 1
As it goes in and out, the phase of the clock to the data is 22
It increases by 5 degrees. Further, as described in the first embodiment, in order to prevent the malfunction of the D latch circuit 101, the phase difference between the edge of the data input and the clock is approximately 22.5 when one cycle of the data input signal is 360 degrees. (360
÷ (2 × 8)) degrees or more are set.

As a modification of the second embodiment, the logical product of the gate 103 may be replaced by the logical sum, and in this case, the position where the pulse is generated is different, but a rotational position similar to that shown in FIG. A signal is generated. Further, in the present invention, the D-latch circuit is basically used as the rotational position detection circuit, but it is also possible to use a counter circuit instead of the D-latch circuit. Although the drawings for explanation are omitted, the idea is as follows.

The FG1 signal is used as the set / reset signal. The FG2 signal is used as the clock. P1 =
Assuming 8, P2 = 65, the counter may advance 8 bits or 9 bits while the FG1 pulse sets and resets the counter. Since there is only one timing to advance 9 bits during one rotation of the rotor, this timing can be detected using a preset circuit or the like.

(Explanation of Third Embodiment) As a third embodiment,
An example in which the above first and second embodiments are applied to a surface-opposed motor will be described. 12 is a plan view seen from the arrow B in FIG. 14 with the rotor unit shown in FIG. 13 removed, and FIG. 13 is a plan view seen from the direction of the arrow B cut along the XX plane in FIG. 15 and 16 of the conventional example, and parts common to those of FIGS. 1 and 2 of the first embodiment are denoted by the same reference numerals. The difference from the circumferentially opposed motor is that the ring-shaped drive magnet 4 becomes a disc-shaped drive magnet 19, the stator yoke 11 disappears, and the coil 10 is replaced by a flat coil 20.

Compared with the conventional surface-opposed motor, the Hall element for detecting the drive timing and the Hall element for detecting the index are eliminated, and the space for arranging the coil 20 can be increased correspondingly. Nevertheless, it is possible to realize a motor with a large generated torque. As the rotational position detecting circuit, the circuit having the same structure as that of the first and second embodiments shown in FIGS. 3 to 9 can be used. 12 and 1
Θ0, θr, and θi shown in FIG. 3 are equivalent to those shown in FIG. In the figure, when θr coincides with θi, it is the moment when the position detection signals rise or fall, and the position of the rotor
One index signal can be generated for each rotation.

In the above-described embodiments and modified examples, two types of pulse signals are generated from the counter electromotive voltage of the coil and the FG signal, and the index signal is generated from those signals. Timing detection element 1
2 (FIG. 16), the position detecting magnet 13, the Hall element 14 and the like are not necessary. For this reason, the motor of the embodiment is considerably miniaturized. Moreover, since the index magnet is no longer needed, the problem of magnetic flux leakage is eliminated.

[0042]

As described above, according to the present invention,
It is possible to provide a low-cost, small-sized / thin-type electromagnetic rotating machine in which the number of constituent parts is reduced without causing any problems due to the leakage magnetic flux.

[Brief description of drawings]

FIG. 1 is a plan view of a rotor portion and a stator portion of a circumferentially opposed motor according to an embodiment of the present invention, which is a diagram for explaining a magnetization pattern common to the first and second embodiments.

2 is a cross-sectional view of the motor of FIG.

FIG. 3 is a block diagram for explaining a method of detecting a first pulse signal FG1 and a second pulse signal FG2 to create a drive timing signal and a position detection signal.

FIG. 4 is a timing chart for explaining a coil energization mode.

FIG. 5 is a diagram showing a relationship between a counter electromotive voltage generated in a coil and a first pulse signal FG1.

6 is a timing chart showing the relationship between the rotational position detection signal generated by the circuit of FIG. 152 and FG1 and FG2.

FIG. 7 is a diagram showing a configuration of a rotational position detection circuit 100 according to the first embodiment.

FIG. 8 is a timing chart illustrating a phase relationship between FG1 and FG2.

9 is a timing chart showing the relationship between the rotational position detection signal generated by the circuit of FIG. 155 and FG1 and FG2.

FIG. 10 is a diagram showing a configuration of a rotational position detection circuit 100 according to a second embodiment.

FIG. 11 is a timing chart for explaining the phase relationship between FG1 and FG2 in the second embodiment.

FIG. 12 is a plan view of a stator portion of a surface-opposed motor according to a third embodiment, and a rotational position detection circuit is the same as in the first and second embodiments.

FIG. 13 is a plan view of a rotor portion of a surface facing motor according to a third embodiment.

FIG. 14 is a partial cross-sectional view of FIGS. 158 and 159.

FIG. 15 is a plan view of a rotor and a stator of a circumferentially opposed three-phase brushless motor according to a conventional technique.

16 is a partial cross-sectional view of the motor shown in FIG.

17 is a diagram showing a power generation line element pattern for FG signal detection of the motor of FIG.

FIG. 18 is a timing chart of signals generated by a magnet for detecting an index and a detection element in the conventional technique.

FIG. 19 is a circuit diagram of an index detection circuit according to a conventional technique.

[Explanation of symbols]

1-turn counter-type motor drive magnet, 2 FG magnet, 4 rotor yoke, 7a generator line element part, 10 drive coil, 12 drive timing detection element, 13 position detection magnet, 15, 16U, 16V, 16W, 17 comparator, 19 They are a drive magnet for the surface-opposed motor, 20 a drive coil for the surface-opposed motor, and 100 rotational position detection circuits.

Claims (8)

[Claims] 1. An electromagnetic rotating machine that generates m position signals per rotation indicating an absolute rotational position of a rotor portion relative to a stator portion, wherein the stator portion of the stator portion is rotated when a drive magnet of the rotor portion is rotated. A counter electromotive voltage generated on the side of the rotating magnetic field is detected to detect a natural number of P1 equal-interval pulse signals FG per rotation.
A first pulse generating means for generating 1 and a magnetic body for generating a magnetic field that rotates in synchronization with the rotation of the rotor section, and change the magnetic field generated by the magnetic body per one rotation of the rotor section. Detect one of the rotors
A natural number of P2 pulse signals FG2 per rotation
And a circuit means for generating the absolute rotation position signal based on the periodicity of the phase difference between the pulse signals FG1 and FG2, the drive magnet, and the rotor unit. The magnetic substance that generates the magnetic field that rotates in synchronization with the rotation of the pulse signal FG
An electromagnetic rotating machine in which the pulse numbers P1 and P2 of 1 and FG2 are both set to a natural number with m as the greatest common divisor. 2. The electromagnetic rotating machine according to claim 1, wherein m = 1 and P2> P1. 3. The electromagnetic rotating machine according to claim 2, wherein P2 = P1 · n ± 1 (n is an integer). 4. The electromagnetic rotating machine according to claim 2, wherein P2 = P1 · (n + 0.5) ± 1 (n is an integer). 5. The circuit means is configured to output the pulse signal FG.
1st circuit part which detects the front-back relationship of the phases of 1 and FG2,
The second circuit section for generating the position signal indicating the absolute rotational position when the front-rear relationship of the phases of the pulse signals FG1, FG2 is reversed and further reversed. Electromagnetic rotating machine. 6. The electromagnetic rotating machine according to claim 5, wherein the circuit means includes a D latch having FG1 as a clock input and FG2 as a data input. 7. The circuit means comprises a D-type latch having FG1 as a clock input and FG2 as a data input, and a 1-bit shift having a clock input of the D latch as a clock input and an output of the D latch as a data input. 7. A logical product or a logical sum of a register, an output signal from the D latch output, and an output of the 1-bit shift register is taken, and the output of the logical product or the logical sum is used as the position signal. 5. The electromagnetic rotating machine described in 5. 8. The phase of the clock is a pulse generated during one rotation of the rotor of the clock, with one cycle of the data input waveform being 360 degrees with respect to the rising or falling of the data input of the D latch. The electromagnetic rotating machine according to claim 6 or 7, wherein when the number is p1, they are separated by approximately 360 / (2 · p1) degrees or more.