JP2006288159A - Resolver device and motor device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size of a resolver device in the direction of motor axis and avoid the influences of flux leakage or magnetic mutual interference between a motor main body and a resolver and between two resolvers without use of a magnetic shielding member. <P>SOLUTION: In the detector of the resolver device, a single-pole resolver 14 and a multi-pole resolver 15 are adjacently disposed in this order along the motor axis direction A in such a direction that they get away from the motor main body 3. Specifically, the resolver stator 20 of the single-pole resolver 14 is placed adjacently to a motor stator 10 with only an air gap in-between, and the resolver stator 21 of the multi-pole resolver 15 is placed adjacently to the resolver stator 20 of the single-pole resolver 14 with only an air gap in-between. The resolver device includes a means for selecting and driving the single-pole resolver 14 when power is turned on, and selecting and driving the multi-pole resolver 15 after power is turned on; and a means for processing signals detected by the resolvers 14 and 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resolver device including a resolver that magnetically detects a rotation angle position and a rotation speed of a rotor (rotor) of an electric motor, and a motor device equipped with the resolver device.

  Conventionally, this type of electric motor has a resolver device as a detector for magnetically detecting the rotational angle position of the rotor with high resolution.

  As an aspect of this resolver device, one described in Patent Document 1 is known. As shown in FIG. 1, the resolver device of the same document detects a unipolar resolver signal (also called an absolute resolver) that detects a unipolar resolver signal (ABS signal) and a multipolar resolver signal (INC signal). And a multipolar resolver (also called an ink resolver).

  The multi-pole resolver and the single-pole resolver are arranged in this order on one end side in the axial direction of the motor body including the motor stator and the motor rotor. Each of the multi-pole resolver and the single-pole resolver includes a resolver stator and a resolver rotor. For this reason, a resolver stator of a multipole resolver is positioned on one end side in the axial direction of the motor stator via a magnetic first shielding plate next to the motor stator, and next to the resolver stator of this multipole resolver. Furthermore, a resolver stator of a single pole resolver is located via another second shielding plate. The two resolver stators and the two shielding plates are supported by the outer housing of the motor.

  As a result, the first shielding plate suppresses magnetic field lines generated due to motor excitation from affecting the multipolar resolver as noise, and the second shielding plate provides a magnetic field between the multipolar resolver and the monopolar resolver. To suppress general interference.

On the other hand, the resolver rotor of each of the multi-pole resolver and the single-pole resolver is supported so as to face a pair of resolver stators through a gap of a predetermined interval in the radial direction of the motor and to rotate integrally with the motor stator. .
JP-A-6-46552

  However, in the resolver device incorporated in the motor described in the above-mentioned publication, the first and the first in order to suppress a decrease in detection accuracy due to magnetic noise and magnetic interference when the motor is turned on and after the power is turned on. 2 double shielding plates are used. For this reason, even if an attempt is made to reduce the size of the resolver device in the axial direction of the motor, since the two shielding plates are present, there is a limit in reducing the size of the resolver device. In the midst of the demand for further downsizing (length), it was one of the factors that hindered downsizing.

  Although a design that does not include such a shielding plate can be considered in pursuit of miniaturization, in such a design, the magnetic flux leakage when the motor stator is excited by receiving a command current is detected by the multipolar resolver. It will be superimposed on the position signal as noise. For this reason, there are problems such as poor positioning and noise when driving as a direct drive motor.

  The present invention has been made in view of such a situation, and the size of the resolver device in the motor axial direction can be further reduced, and the leakage magnetic flux between the motor body and the resolver and between the two resolvers and the magnetic It is an object of the present invention to provide a resolver device capable of avoiding the influence of mutual interference and a motor device using the resolver device.

  In order to achieve the above-described object, according to a resolver device according to the present invention, a resolver is provided in a motor in which a motor rotor and a motor stator are arranged to face each other with a gap of a predetermined distance. A first resolver for detecting a signal corresponding to the rotation of the motor rotor when the power is turned on, and a second resolver for detecting a signal corresponding to the rotation of the motor rotor in a driving state after the motor is turned on. The resolver stator of the first resolver is adjacent to the motor stator via a gap only, and the resolver stator of the second resolver is adjacent to the resolver stator of the first resolver only via a gap. And switching to the first resolver when the power is turned on to drive the first resolver, Drive means for switching to the second resolver after driving and driving the second resolver; and processing means for processing the signals detected by the first and second resolvers to obtain the signal. It is characterized by that.

  Further, according to the motor device of the present invention, as the motor main body, a motor rotor supported rotatably around the axial direction of the motor main body and a predetermined distance in a radial direction orthogonal to the axial direction of the motor rotor. A motor stator disposed opposite to each other through a gap, and a resolver that detects a signal indicating rotation of the motor rotor on one end side in the axial direction of the motor body, and the resolver is disposed in the axial direction. In the structure formed by first and second resolvers of different types arranged in order along with each other, the signal of the motor rotor when the motor is turned on is used as the first resolver adjacent to the motor body. Driving after the resolver to be detected is disposed and the motor of the motor is turned on as the second resolver adjacent to the first resolver Characterized by being arranged resolver for detecting the signal of the motor rotor in state.

  According to the present invention, it is possible to further reduce the size of the resolver device in the axial direction of the motor without using a magnetic shielding member as in the prior art, and between the motor body and the resolver and between the two resolvers. The effects of magnetic flux leakage and magnetic mutual interference can be avoided.

  Hereinafter, the best mode for carrying out the present invention will be described as an embodiment.

  With reference to FIGS. 1-12, one Embodiment of the motor which concerns on this invention is described. This motor has a configuration in which the resolver device according to the present invention is integrally mounted (incorporated), and the configuration and operation of the resolver device will be described together in the description of this motor.

FIG. 1 shows a partially broken appearance centering on a machine frame of an AC resolver-equipped motor 1 (hereinafter simply referred to as a motor) as a direct drive motor according to the present embodiment. As shown in FIG. 1, the motor 1 includes a machine casing 2 in which mechanical parts are integrally assembled, and an electric system housed in the machine casing 2 is driven and controlled by a drive unit 60. (See FIG. 8). The motor 1 and the drive unit 60 constitute a motor device according to the present invention.

  As will be described later, a resolver as a detector is incorporated in the machine casing 2, and a signal output from the resolver is processed by driving the resolver in the drive unit 60 to rotate the rotational position and rotation of the motor rotor. A drive unit that generates data indicating the speed is included. For this reason, in this embodiment, the resolver device is formed by a partial configuration (a servo drive and a CPU described later) of the resolver and drive unit 60.

  The motor 1 is mainly composed of a machine casing 2, a motor main body 3 incorporated in the machine casing 2, and a detector 4 including a single pole resolver 14 and a multipolar resolver 15 assembled to the machine casing 2. Has been.

  Specifically, the machine casing 2 is assembled to the housing base 5 with an inner housing 6 and an outer housing 7 fixed concentrically with bolts 8. For the material of the outer housing 7 and the like, iron is selected for cost reduction.

  The motor body 3 includes an inner stator (stator) 9 on the inner housing 6 side and an outer stator (stator) 10 on the outer housing 7 side between the inner housing 6 and the outer housing 7. A rotor (rotor) 11 is positioned between the internal stator 9 and the external stator 10 and is rotatably supported by a shaft (see FIG. 2). Therefore, detailed description is omitted.

  As shown in FIG. 3, the single pole resolver 14 includes a resolver rotor 12 and a resolver stator 20, and the multipolar resolver 15 includes a resolver rotor 13 and a resolver stator 21. Here, the motor main body 3, the single pole resolver 14, and the multipolar resolver 15 are arranged in this order toward the motor end in the motor axial direction A. That is, unlike the prior art, the arrangement positions of the monopolar resolver 14 and the multipolar resolver 15 in the motor axial direction A are opposite, and the monopolar resolver 14 is arranged between the motor body 3 and the multipolar resolver 15. It is characterized by being.

  The resolver rotors 12 and 13 of these resolvers 14 and 15 are fixed to the rotor 11 by bolts 19 via a rotor spacer 18, while the resolver stators 20 and 21 of these resolvers 14 and 15 are provided with a resolver holder 22. And is fixed to the inner peripheral surface of the outer housing 7 by a bolt 23. The rotor spacer 18 is formed as a spacer made of SUS (stainless steel) and functions as a non-magnetic material that hardly allows magnetic flux to pass therethrough. The permeability of the rotor spacer 18 has a value close to that of air. A disk 24 made of a silicon steel plate is provided on the portion of the rotor 1 that faces the end of the single pole resolver 14 on the motor body 3 side.

  As shown in FIG. 3, the resolver holder 22 is formed to have an outer diameter such that the outer peripheral wall surface 22a is in close contact with the inner peripheral wall surface 7a of the outer housing 7 opposite to the motor body 3 (upper side in FIG. 3). In addition, the resolver stators 21 and 20 are divided into upper and lower parts in two upper and lower stages. Reference numerals 26 and 27 denote resolver stator mounting steps.

  Above the upper holder 28 that forms one side of the resolver holder 22, a room 29 for accommodating the multipolar resolver 15 is defined by partitioning an end portion with a ceiling cover 30. A room 31 for accommodating the monopolar resolver 14 is defined below the upper holder 19 in the figure.

  In addition, the resolver holder 22 itself has an original function of supporting the stators 20 and 21 of the monopolar resolver 14 and the multipolar resolver 15, and the magnetic flux of the resolvers 14 and 15 is an external iron outer housing. 7 also has a function of preventing leakage.

  As described above, in the detector structure including the monopolar resolver 14 and the multipolar resolver 15, the multipolar resolver 15 is disposed on the motor end side away from the motor body 3, and instead, the monopolar resolver 14 is provided. It arrange | positions between the multipolar resolver 15 and the motor main-body part 3, and adjoins the motor main-body part 3. FIG. Thus, unlike the conventional structure, there is no need to provide a shielding plate for magnetic shielding between the monopolar and multipolar resolvers 14 and 15, and the monopolar resolver 14 and the motor main body 3 (that is, It is not necessary to provide a shielding plate for magnetic shielding between the external stator 10). For this reason, since the structure of the detector is simplified, the size of the detector, that is, the motor 1 in the axial direction A can be made more compact because the space for providing the shielding plate is unnecessary. It is also effective in reducing component costs. This simple structure without a shielding plate can be realized in combination with a drive system (described later) for driving the monopolar resolver 14 and the multipolar resolver 15 and constitutes a feature on the resolver arrangement according to the present invention.

As shown in FIG. 4, the resolver rotor 12 and the resolver stator 20 of the single pole resolver 14 are three-phase variable reluctance resolvers, and the gap 35 between the rotor core 12a and the stator core 20a varies depending on the circumferential position of the rotor core 12a. And it has the structure where the fundamental wave component of the reluctance change becomes one cycle by one rotation of the rotor core 12a. That is, the inner diameter center O ₁ of the rotor 12 coincides with the inner diameter center of the stator 20, but the rotor core 12 a so that the outer diameter center O ₂ of the rotor 12 is eccentric from the inner diameter center O ₁ by a constant eccentric amount A. The reluctance varies depending on the rotational position of the rotor core 12a.

The resolver stator 20 is composed of three phases of A phase, B phase and C phase arranged at intervals of 120 °, and A arranged at 180 ° offset from the A phase, B phase and C phase. Bar phase (refers to a phase with a horizontal line on the head of A), B bar phase (refers to a phase with a horizontal line on the head of B), and C bar phase (a phase with a horizontal line on the head of C) Magnetic poles) are arranged. Each of these phases is provided with three magnetic poles, and a total of 18 magnetic poles 36 _{1 to} 36 ₁₈ are provided on the stator 20. One type of windings C _{1 to} C ₁₈ are wound around the magnetic poles 36 _{1 to} 36 ₁₈ . As shown in FIG. 5, the _three windings C ₁ , C ₂ , C ₃ of the A phase are connected in series, and the three windings of the other phases are also connected in series like the A phase. It is connected. The three A-phase windings C _{1 to} C ₃ are connected between the common terminal 37 and one end of the current detection resistor R ₁ . The other three windings of each phase are also connected between the common terminal 37 and one ends of the current detection resistors R _{2 to} R ₆ , as in the A phase. The other ends of R _{1 to} R ₆ are grounded internally.

  In the unipolar resolver 14 having the above-described configuration, when a sine wave having a frequency at the common terminal 37 is applied as an excitation signal, each of the windings of the A phase, the B phase, and the C phase starts from the windings of the A phase, B phase, and C phase. A single-phase resolver signal having a phase shift of 120 ° for each phase and having a current value changed in accordance with the change in reluctance is output. And from each of the windings in the C-bar phase, single-pole resolver signals that are 180 degrees out of phase with respect to the A-phase, B-phase, and C-phase signals are output.

  As shown in FIG. 6, the outer diameter center of the rotor 13 of the resolver rotor 13 and the resolver stator 21 of the multipolar resolver 15 coincides with the inner diameter center of the stator 21. A large number (for example, 150 pieces) of salient pole-shaped teeth 13 a are formed on the outer peripheral surface of the rotor 13. The A-phase, B-phase, and C-phase magnetic poles are alternately arranged at predetermined intervals on the inner peripheral portion of the stator 21, and windings Ca, Cb, and Cc are wound around the magnetic poles of the respective phases. ing. A large number of salient pole-like teeth (for example, 144 in the case of 150 teeth 13a of the rotor 13) are formed on the inner peripheral surface of the stator 21 so that the electrical angle of each phase is shifted by 120 °. Has been. As shown in FIG. 7, the windings Ca, Cb, Cc of each phase are connected between the common terminal 38 and one end of the current detection resistors Ra, Rb, Rc, respectively. The other ends of Ra, Rb, and Rc are grounded.

  In the multipolar resolver 15 having the above configuration, when a sine wave having a frequency at the common terminal 38 is applied as an excitation signal, 150 cycles of AC signals are generated for each of the three phases while the rotor 13 rotates once. The signal is output from the windings Ca, Cb, Cc as a pole resolver signal.

  FIG. 8 shows a configuration of a drive unit 60 that also has a configuration on the drive processing side of the resolver device.

  The drive unit 60 supplies an excitation signal to one of the single-pole resolver 14 and the multi-pole resolver 15, takes in the resolver signal, outputs a digital angle signal φ, and a rotation angle position signal from the digital angle signal φ. And a CPU 61 for supplying electric power to the monitor main body 3 of the direct drive motor 10 through a power amplifier 62. The drive unit 60, the single pole resolver 14 and the multipolar resolver 15 are connected by a resolver cable 71, and the unit 60 and the motor body 3 are connected by a motor cable 72.

  The servo driver 50 amplifies the excitation signal output from the transmitter 51 to an appropriate signal level by the amplifier 52, and the common terminal COM 1 of the unipolar resolver 14 and the common terminal of the multipolar resolver 15 through the changeover switch 53. The excitation signal is supplied to one of the COMs 2 by switching the excitation signal supply path. The changeover switch 53 is a switching means that is arranged on the excitation signal supply path from the transmitter 51 to the single pole resolver 14 and the multipolar resolver 15 and switches the supply path of the excitation signal to these resolvers. The connection switching of the selector switch 53 to the common terminals COM1 and COM2 is controlled by a switch switching signal output from the CPU 61.

  Immediately after the power is turned on and the system is started, the CPU 61 switches and connects the changeover switch 53 to the common terminal COM1, thereby supplying an excitation signal to the unipolar resolver 14. The current signal output from the unipolar resolver 14 is converted into a unipolar resolver signal (ABS signal) by the current / voltage converter 41a, and then the two-phase signal (sin signal, cosine signal) is output by the 3/2 phase converter 42a. And is supplied to the analog switch 43.

Here, if the transmission angular frequency of the transmitter 51 is ω and the higher-order components are ignored, the resolver signal of each phase obtained by the current / voltage converter 41a is as shown in the following equations (1) to (3). It becomes. Here, for convenience of explanation, a case where the phases of the B phase and the C phase are respectively delayed by 120 degrees with respect to the A phase is illustrated. Further, the two-phase signals obtained by the 3 / 2-phase converter 42a are shown in the equations (4) to (5). In equation (5), sqr (x) is a function that returns the square root of the argument x.
φA = (A ₁ + A ₂ sin θ) · sin ωt (1)
φB = {B ₁ + B ₂ sin (θ−2π / 3)} · sin ωt (2)
φC = {C ₁ + C ₂ sin (θ−4π / 3)} · sin ωt (3)
sin signal = φA− (φB + φC) / 2 (4)
cos signal = sqr (3/4) · (φB−φC) (5)

  On the other hand, after the CPU 61 obtains the value of the digital angle signal φ (abs described later) from the unipolar resolver signal, the CPU 61 switches and connects the changeover switch 53 to the common terminal COM2. As a result, the excitation signal is supplied to the multipolar resolver 15. The current signal output from the multipolar resolver 15 is converted into a multipolar resolver signal (INC signal) by the current / voltage converter 41b, and then the two-phase signal (sin signal, cosine signal) is output by the 3/2 phase converter 42b. And is supplied to the analog switch 43.

  The analog switch 43 is a switching element that is controlled to be switched by an ABS / INC switching signal from the CPU 61. The analog switch 43 selectively passes either a two-phase ABS signal or a two-phase INC signal to receive an RDC (resolver digital signal). Converter) 44. The CPU 61 performs analog synchronization so that the timing at which the signal passing through the analog switch 43 is switched from the two-phase ABS signal to the two-phase INC signal and the timing at which the switch 53 is connected from COM1 to COM2 are substantially synchronized. An ABS / INC switching signal is output to the switch 43.

  The phase shifter 45 delays the phase of the excitation signal output from the transmitter 51, and synchronizes with the phase of the carrier signal of the sin signal and cos signal of the ABS signal or INC signal converted into two phases ( Ref signal) is supplied to the RDC 44. The RDC 44 digitizes the two-phase signal supplied from the analog switch 43 and outputs a digital angle signal φ to the CPU 61. The RDC 44 outputs an analog speed signal after synchronous rectification based on the oscillation angular frequency of the transmitter 51.

In the above description, the configuration using a three-phase resolver as the monopolar resolver 14 is exemplified, but the present invention is not limited to this, and a six-phase resolver can also be used as the monopolar resolver 14. When using a 6-phase resolver, the following equations (6) to (11) are used instead of the above equations (1) to (3) as the resolver signal, so as shown in FIG. A subtractor 46a may be interposed between the current / voltage converter 41a and the 3 / 2-phase converter 42a. The subtractor 46a calculates the difference dA, dB, dC of the resolver signal of each phase and converts the 6-phase resolver signal into a 3-phase resolver signal of the expressions (12) to (14). The three-phase resolver signal of the same formula is converted into a two-phase signal by the 3/2 phase converter 42a.
φA + = (A ₁ + A ₂ sin θ) · sin ωt (6)
φA − = (A ₁ + A ₂ sin (θ−π)) · sin ωt (7)
φB + = {B ₁ + B ₂ sin (θ−2π / 3)} · sin ωt (8)
φB − = {B ₁ + B ₂ sin (θ−2π / 3−π)} · sin ωt (9)
φC + = {C ₁ + C ₂ sin (θ−4π / 3)} · sin ωt (10)
φC − = {C ₁ + C ₂ sin (θ−4π / 3−π)} · sin ωt (11)
dA = 2A ₂ sin θ · sin ωt (12)
dB = 2B ₂ sin (θ-2π / 3) · sinωt (13)
dC = 2C ₂ sin (θ-4π / 3) · sinωt (14)

  Furthermore, for example, when other types of resolvers such as a two-phase resolver and a four-phase resolver are used, the configuration of the detection circuit unit 40 may be appropriately changed according to each case.

FIG. 10 is a graph of a digitally converted resolver signal. If a 12-bit converter is used as the RDC 44, the two-phase ABS signal is converted into a digital angle signal φ of 4096 (= 2 ¹² ) pulses per resolver rotor rotation, as shown in FIG. That is, the unipolar resolver signal (ABS signal) becomes a digital value counted up from 0 to 4095 while the unipolar resolver 14 makes one revolution. On the other hand, the two-phase multipolar resolver signal (INC signal) is converted into a digital angle signal φ of 4096 × 24 (total number of pole teeth 35) = 98304 pulses per revolution of the resolver rotor, as shown in FIG. The That is, the multipolar resolver signal becomes a digital value in which the count up from 0 to 4095 is repeated 24 times while the multipolar resolver 15 makes one rotation.

  In the figure, the offset value is one fundamental wave out of the 24 period fundamental wave components of the multipolar resolver signal when the rotation angle corresponding to the starting point of the fundamental wave component of the unipolar resolver signal is 0 degree. It is the value of deviation from the component.

  The CPU 61 takes in these digital angle signals φ and calculates the rotational angle position of the direct drive motor 1. The value of the digital angle signal φ converted from the two-phase monopolar resolver signal into the digital signal by the RDC 44 is abs, and the value of the digital angle signal φ converted from the two-phase multipolar resolver signal into the digital signal at the RDC 44 is inc. Then, the rotation angle position can be obtained by calculating abs × 24 + (2048−inc) + offset value. The CPU 61 instructs the power amplifier 62 to supply power to the direct drive motor 1 based on the rotation angle position.

  In order to obtain the digital angle signal φ from the resolver signal, it is not always necessary to process it by a hardware circuit (3/2 phase converter, RDC, etc.). The resolver signal is A / D converted and information by software A digital angle signal φ may be obtained by processing.

  FIG. 11 is a flowchart describing the position detection processing routine of the CPU 61. The above description will be described again with a focus on the control processing of the CPU 61 with reference to FIG. When the CPU 61 detects that the power is turned on when the system is stopped (step S1; YES), the CPU 61 outputs a switch change signal so as to connect the changeover switch 53 to the common terminal COM1 (step S2). In response to this, the excitation signal output from the transmitter 51 is supplied from the common terminal COM1 to the single pole resolver 14, and the reluctance change corresponding to the rotation angle position is supplied to the detection circuit unit 40 as a current signal.

  In the detection circuit unit 40, the current signal is converted into a voltage signal by the current / voltage converter 41 a, converted into a two-phase signal by the 3 / 2-phase converter 42 a, and supplied to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase unipolar resolver signal (ABS signal) as a signal to pass through the analog switch 43 (step S3).

  The two-phase unipolar resolver signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61 as a digital angle signal φ. The CPU 61 acquires the value of this digital angle signal φ as abs (step S4).

  Next, the CPU 61 outputs a switch change signal so as to connect the changeover switch 53 to the common terminal COM2 (step S5). In response to this, the excitation signal output from the transmitter 51 is supplied from the common terminal COM2 to the multipolar resolver 15, and the reluctance change corresponding to the rotation angle position is supplied to the detection circuit unit 40 as a current signal.

  In the detection circuit unit 40, the current signal is converted into a voltage signal by the current / voltage converter 41 b, converted into a two-phase signal by the 3 / 2-phase converter 42 b, and supplied to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase multipolar resolver signal (INC signal) as a signal to pass through the analog switch 43 (step S6).

  The two-phase multipolar resolver signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61 as a digital angle signal φ. The CPU 61 acquires the value of the digital angle signal φ as inc (step S7).

  Until the power is turned off, the CPU 61 controls the changeover switch 53 to remain connected to the common terminal COM2, while the signal passing through the analog switch 43 is maintained as a two-phase multipolar resolver signal. (Step S8; NO). When the CPU 61 detects that the power is off (step S8; YES), the control routine is terminated.

  As described above, according to the present embodiment, the excitation signal is supplied to only one of the single pole resolver 14 and the multipolar resolver 15 so that they are not excited simultaneously.

In the motor 1, the single pole resolver signal from the single pole resolver 14 is necessary for obtaining the absolute mechanical angle position when the power is turned on (usually about 0.5 seconds after the power switch is turned on). However, it is because only the multipolar resolver signal from the multipolar resolver 15 is required in the motor rotational motion state after the power is turned on.

  Since the motor body 3 is not excited when the power is turned on, the monopolar resolver 14 is not affected by excitation noise from the motor body 3. Therefore, the single pole resolver 14 outputs a single pole resolver signal without being affected by the leakage magnetic flux from the motor main body 3, and this signal is sent to the drive unit 60 as described above to drive the motor main body 3. Used for. At this time, since the unipolar resolver signal is not affected by magnetic noise, such driving is also performed with high accuracy.

  In the detector, the detection source is switched to the multipolar resolver 15 side at an appropriate timing after the power is turned on, and motor drive control such as positioning control is executed using the multipolar resolver signal. In this operating state, the leakage magnetic flux generated with the excitation of the motor body is alternatively shielded by the adjacent monopolar resolver 14. The state of this shielding is schematically shown in FIG.

  That is, the single pole resolver 14 that is not used when the motor is operating functions as a magnetic shielding plate, and the leakage magnetic flux hardly circulates to the adjacent multipolar resolver 15, and the motor to the multipolar resolver 15 is not used. There is almost no magnetic influence from the main body 3. Therefore, the multipolar resolver signal output from the multipolar resolver 15 is not magnetically affected, and the position detection performance is not deteriorated.

  Of course, by selectively exciting the monopolar resolver 14 and the multipolar resolver 15, the leakage magnetic flux of one resolver does not cause magnetic interference to the other resolver.

  Thus, according to the detector according to the present embodiment, the order of the resolver arrangement with respect to the motor main body 3 is set to the order of the monopolar resolver 14 and the multipolar resolver 15, and then both resolvers 14 and 15 are arranged. By selectively exciting at the time of power-on and after that, it is possible to detect the position with high accuracy by avoiding the influence of magnetic noise and to eliminate the need for the magnetic shielding plate used in the conventional structure. . Since the magnetic shielding plate is unnecessary, the facing distance between the motor body 3 and the monopolar resolver 14 and the facing distance between the monopolar resolver 14 and the multipolar resolver 15 are shortened to an allowable limit value. it can. As a result, the stator coil of the single-pole resolver 14 and the stator coil of the multi-pole resolver 15 can be shortened to substantially contact each other, and the direct drive motor 1 can be reduced in size and thickness.

  In addition, since the two shielding plate members described above can be omitted, the number of parts can be reduced and the cost can be reduced.

  The structure of the present embodiment is suitable for a direct drive motor that can be used for a small and highly accurate positioning used for an index table such as an NC machine tool, a transfer device, a robot arm of an assembly device, or the like.

  In addition, since the present embodiment is configured to always supply the excitation signal to either one of the unipolar resolver 14 and the multipolar resolver 15, the power consumption compared to the conventional configuration that supplies the excitation signal to both resolvers. Can be reduced to approximately half. Furthermore, since the current signal output from each of the monopolar resolver 14 and the multipolar resolver 15 does not crosstalk in the resolver cable 71, the position detection accuracy can be increased.

  In the above description, the configuration including the monopolar resolver 14 and the multipolar resolver 15 as the resolver incorporated in the direct drive motor 1 is illustrated, but the present invention is not limited to this, and any different type of resolver can be used. The present invention can also be applied when incorporated in the direct drive motor 1. A configuration example in which two types of multipolar resolvers are combined will be exemplified below.

(Combination example 1)
This combination example is a type that implements a PM motor rotor position detection function. A resolver having the same number of poles (for example, 20 teeth) as the number of poles of the PM motor is used as a first resolver, and a resolver for high resolution position detection. (For example, 120 teeth) is used as the second resolver. For example, when the power is turned on, first the digital angle signal is read by the first resolver, and then the digital angle signal is read by switching to the second resolver to detect the rotational position of the rotor from the phase difference with the PM motor. Therefore, thereafter, the excitation timing of the PM motor can be recognized together with the rotation angle position based on the signal from the second resolver. That is, since the first resolver functions as a substitute for the UVW sensor (for example, a Hall element), the UVW sensor can be omitted.

(Combination example 2)
In this combination example, the absolute angular position of the rotor 11 is detected, and the (N + 1) pole resolver is the first resolver and the N pole resolver is the second resolver. However, N is an integer of 2 or more. Since the difference in the number of poles between the first resolver and the second resolver is 1, the absolute angular position of the rotor 11 can be detected from the difference between the _two digital angle signals φ ₁ and φ ₂ . As the excitation switching timing of these resolvers, for example, it is desirable to excite the first resolver when the system power is turned on to read the digital angle signal φ ₁ and then excite the second resolver. By keeping the excitation state of the second resolver until the power is turned off, the absolute angle position of the rotor 11 is determined from the digital angle signal φ ₁ read at the system startup and the digital angle signal φ ₂ detected by the second resolver thereafter. Can be detected.

(Combination example 3)
This combination example is a type that detects the absolute angular position of the rotor 11 within a predetermined angular range. To detect the absolute angular position within an angular range of 360 degrees / M, the M pole resolver is the first resolver, A resolution resolver (for example, 120 poles) is used as the second resolver. However, M is an integer of 2 or more. By combining the multipolar resolver in this manner, for example, the robot arm is suitable for use in turning within a predetermined range of angles such as 180 degrees, 120 degrees, and 90 degrees. The rotor shape of the first resolver is not particularly limited as long as the gap between the resolver rotor and the resolver stator changes periodically, and various shapes can be adopted. For example, if a first resolver having two poles is manufactured, various shapes such as an elliptical shape, a gourd shape, and a tooth shape can be employed as the shape of the resolver rotor.

  It should be noted that the present invention is not limited to the above-described embodiments and modifications thereof, and those skilled in the art can implement the present invention by appropriately modifying it in combination with a well-known configuration within the scope of the gist of the present invention. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view of a direct drive motor equipped with a resolver device according to an embodiment of the present invention, partially broken away. The side view which fractures | ruptures and shows a part of motor which concerns on embodiment. The fragmentary sectional view along the axial direction of the motor for showing the composition of the detector of the resolver device concerning an embodiment. Sectional drawing orthogonal to the axial direction of the motor which shows the structure of the single pole resolver employ | adopted by embodiment. The connection diagram of the stator coil of a single pole resolver. Sectional drawing orthogonal to the axial direction of the motor which shows the structure of the multipolar resolver employ | adopted by embodiment. The connection diagram of the stator coil of a multipolar resolver. The block diagram which shows the structure of the drive unit of a resolver apparatus. The block diagram which shows a part of hardware constitutions concerning another example of a detection circuit part. The graph which shows the resolver signal after digital conversion. The flowchart which shows an angular position detection process routine. The figure explaining a mode that the leakage flux accompanying the excitation of a motor main-body part is shielded alternatively by the adjacent single pole resolver in a motor driving | running state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Direct drive (DD) motor 2 ... Machine frame 3 ... Motor main-body part 6, 7 ... Housing 9, 10 ... Motor stator 11 ... Motor rotor 14 ... Single pole resolver (1st resolver) 15 ... Multipole resolver (2nd 12, 13 ... resolver rotor 18 ... spacer 20, 21 ... resolver stator 22 ... resolver holder 40 ... detection circuit unit 41 ... current / voltage converter 42 ... 3/2 phase converter 43 ... analog switch 44 ... RDC 45 ... Phase shifter 50 ... Servo driver 53 ... Changeover switch 60 ... Drive unit 61 ... CPU

Claims (7)

A resolver disposed in a motor in which a motor rotor and a motor stator are opposed to each other with a gap of a predetermined distance, and detects a signal corresponding to the rotation of the motor rotor when the motor is turned on. And a second resolver for detecting a signal corresponding to the rotation of the motor rotor in a driving state after turning on the power of the motor,
The resolver stator of the first resolver is disposed adjacent to the motor stator via only a gap, and the resolver stator of the second resolver is disposed adjacent to the resolver stator of the first resolver via only a gap. ,
Driving means for driving the first resolver by switching to the first resolver when the power is turned on, and driving the second resolver by switching to the second resolver after the power is turned on;
And a processing unit for processing the signals detected by the first and second resolvers to obtain the signals.   The resolver device according to claim 1, wherein the first resolver is a monopolar resolver, and the second resolver is a multipolar resolver. As a motor main body, a motor rotor supported to be rotatable about the axial direction of the motor main body, and a motor stator arranged to face each other with a predetermined distance in the radial direction perpendicular to the axial direction of the motor rotor And with
A resolver that detects a signal indicating rotation of the motor rotor on one end side in the axial direction of the motor body;
In the motor device having a structure in which the resolver is formed by first and second resolvers of different types arranged in order along the axial direction.
As the first resolver adjacent to the motor body, a resolver for detecting the signal of the motor rotor when the motor is turned on is disposed.
A motor device comprising: a resolver that detects the signal of the motor rotor in a driving state after the power of the motor is turned on as the second resolver adjacent to the first resolver.   The motor device according to claim 3, wherein the first resolver is a unipolar resolver, and the second resolver is a multipolar resolver. The motor stator is disposed inside the outer housing;
Each of the first and second resolvers includes a resolver rotor and a resolver stator that are opposed to each other via a gap in the radial direction,
The two resolver stators of the first and second resolvers are supported on the inner peripheral surface of the outer housing via a resolver holder, and the two resolver rotors of the first and second resolvers are connected to the motor rotor. The motor device according to claim 3 or 4, wherein the motor device is supported at one end portion in the axial direction with a spacer interposed therebetween.   6. The resolver stator of the first resolver is adjacent to the motor stator with only a gap, and the resolver stator of the second resolver is adjacent to the resolver stator of the first resolver with only a gap. The motor apparatus as described. Driving means for switching to the first resolver to drive the first resolver when the power is turned on, and driving the second resolver by switching to the second resolver after the power is turned on;
The motor apparatus as described in any one of Claims 3-6 provided with the process means which processes the signal which the said 1st and 2nd resolver detected, and obtains the said signal.

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