JP3972355B2 - Direct drive motor system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improved technique for a direct drive motor system including a variable reluctance resolver.
[0002]
[Prior art]
As a detector for detecting the rotational angle position of a direct drive motor that directly drives a load without using a speed reducer, in Japanese Patent No. 30605525, when the rotor iron core makes one rotation, The rotation angle position, which is the absolute positional relationship between the rotor and the stator, is detected from a single pole resolver signal obtained from a single pole resolver having a structure in which the fundamental wave component of the reluctance is one cycle. Proposed a resolver device that can detect the absolute position with high resolution by detecting the rotational angle position with high resolution from the multipolar resolver signal obtained from the multipolar resolver having a structure in which the fundamental component of the reluctance has a plurality of periods. Has been.
[0003]
The conventional resolver device has a configuration in which a three-phase AC excitation winding is wound directly on a substantially T-shaped magnetic pole protruding from the stator, so that a uniform winding state is realized for a large number of magnetic poles. This is extremely difficult, and the resolver signal between the phases varies. For this reason, conventionally, the above-mentioned variation is obtained after the multi-phase output signal from the resolver provided in the direct drive motor is converted into a two-phase output signal (sin signal, cos signal) by the phase conversion circuit provided in the drive unit. The correction data for correcting the loss of balance between the phases due to the above was taken in, and a digital position signal was obtained by a resolver digital converter (Japanese Patent Laid-Open No. 12-262081).
[0004]
[Problems to be solved by the invention]
However, the correction data mounted on the drive unit differs depending on each direct drive motor. In particular, in a direct drive motor including an absolute position detection resolver and a relative position detection resolver, variations in the relative position detection resolver can be corrected by the correction data described above. Since the variation cannot be corrected by the above-described correction data, conventionally, such a variation of the direct drive motor cannot be corrected. Therefore, when exchanging a direct drive motor or drive unit alone for reasons such as failure or maintenance, there is no compatibility between products, so from the direct drive motor, drive unit, and cables that connect the two (resolver cable, motor cable) The entire direct drive motor system had to be replaced as a whole.
[0005]
Conventionally, as the resolver cable for transmitting the resolver signal to the drive unit, the number required for signal detection is arranged at an arbitrary position in the cable, but the positional relationship of each detection signal in the resolver cable is asymmetric. In some cases, with the change in the cable length, there has been a problem of causing electrical interference, and ensuring the compatibility of the resolver cable used in the direct drive motor system has also been a problem.
[0006]
Therefore, the present invention corrects variations in resolver coils provided in a direct drive motor having an absolute position detection function and adopts a cable structure that prevents mutual interference of resolver signals, thereby providing a compatible direct drive. The problem is to propose a motor system.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, in the direct drive motor system of the present invention, the fundamental wave component of reluctance in the gap between the first rotor and the first annular stator becomes one cycle by the rotation of the first rotor. A single-pole resolver, and a multi-pole resolver in which the fundamental wave component of reluctance in the gap between the second rotor and the second annular stator is a plurality of periods by the rotation of the second rotor. A direct drive motor that outputs a multiphase resolver signal, a drive unit that outputs an excitation current for driving the direct drive motor based on the multiphase resolver signal output from the direct drive motor, and an output from the direct drive motor And a resolver cable for transmitting a multiphase resolver signal to the drive unit. In the direct drive motor system, the first and second annular stators have columnar magnetic poles circumferentially arranged, and by inserting a stator coil wound around a coil bobbin into the magnetic poles, The coil position can be freely positioned.
[0008]
With such a configuration, it is possible to correct variations in the resolver coil position and the like, and to provide a compatible direct drive motor system. In addition, since the interchangeability of the direct drive motor and the like is ensured, it is excellent in convenience in system repair and maintenance.
[0009]
Also, the resolver cable used in the direct drive motor system of the present invention is adjusted so that the distance between the signal lines of each phase of the multiphase resolver signal and the distance between each signal line and the common line is substantially constant. Is desirable. With this configuration, electrical interference of signal lines can be suppressed.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present embodiment will be described with reference to the drawings.
[0011]
FIG. 1 is a configuration diagram of a direct drive motor system according to the present embodiment. The system includes a direct drive motor 10 for rotationally driving the rotary shaft 11, a drive unit 20 that controls the drive of the direct drive motor 10, a resolver cable 41 that connects the two, and a motor cable 42. The drive unit 20 supplies an excitation signal to the absolute position detection resolver and the relative position detection resolver built in the direct drive motor 10 via the resolver cable 41 and the resolver terminal 31, and is output from each resolver. From the controller circuit 21 and the controller 30 that take in the multi-phase resolver signal, convert it into a two-phase output signal, take in the correction data built in the correction ROM 22, perform R / D conversion, and output the digital position signal to the controller 30. In order to accurately control the rotational angle position of the direct drive motor 10 by the feedback control, a power amplifier circuit 23 for supplying an excitation current to the motor terminal 32 via the motor cable 42 is provided.
[0012]
FIG. 2 is a sectional view of the direct drive motor 10. As shown in the figure, a rotary shaft 11 accommodated in a hollow cylindrical housing 12 is rotatably supported by a direct drive motor 10 via a cross roller bearing 19. The cross roller bearing 19 includes an inner ring 18 positioned in the housing 12, an outer ring 16 positioned on the inner peripheral surface of the lower end of the rotary shaft 11, and a rolling element 17 disposed between the two. The outer ring surface of the inner ring 18 is formed with an outer track groove having an isosceles right triangular shape with a cross section composed of a first inclined track surface and a second inclined track surface orthogonal to each other. An inward groove groove having a right isosceles triangular cross section formed by a third inclined track surface and a fourth track surface orthogonal to each other is formed. The rolling elements 17 are positioned between a plurality of first rolling elements 17 that are in rolling contact with the first inclined track surface and the fourth inclined track surface, respectively, and the second inclined track surfaces that are adjacent to each other. It consists of a second rolling element 17 that is in rolling contact with the third inclined track surface.
[0013]
A silicon steel plate is laminated on the outer peripheral surface of the lower end portion of the rotating shaft 11, and an annular motor rotor 15 having a plurality of pole teeth protruding outward in the radial direction is fitted and fixed. A motor stator 13 having a plurality of magnetic poles laminated on the surface and projecting radially inward is disposed. The magnetic pole has a substantially T-shape, and the stator coil 14 for generating a rotating magnetic field is wound by the exciting current supplied from the power amplifier circuit 23 via the motor cable 42. A large number of magnetic pole teeth are formed at positions facing the pole teeth with a predetermined gap.
[0014]
The rotary shaft 11 is provided with a resolver 50 for detecting the absolute angular position of the rotary shaft 11 and a resolver 60 for detecting the relative angular position. The resolver 50 is a resolver rotor 55 composed of an annular stratified iron core fixedly contacted to the inner peripheral surface of the rotating shaft 11, a resolver stator 51 composed of an annular stratified iron core fixed to the housing 12 and facing the resolver rotor 55, and a resolver stator 51. It is a single pole resolver comprised from the stator coil 54 wound by the magnetic pole. The resolver 60 is a resolver rotor 65 composed of an annular stratified iron core fixedly contacted with the inner peripheral surface of the rotating shaft 11, a resolver stator 61 composed of an annular stratified iron core fixedly contacted with the housing 12 and facing the resolver rotor 65, and a resolver stator 61. It is a multipolar resolver comprised from the stator coil 64 wound by the magnetic pole.
[0015]
FIG. 3 is a sectional view of the absolute position detecting resolver 50. As shown in the figure, the resolver 50 is a three-phase variable reluctance resolver, and the reluctance of the gap between the resolver stator 51 and the resolver rotor 55 varies depending on the rotational angle position of the resolver rotor 55, and the resolver rotor 55 is rotated once. It has a structure in which the fundamental wave component of the reluctance change is one cycle. That is, the outer diameter center and inner diameter center of the resolver stator 51 and the outer diameter center of the resolver rotor 55 coincide with the rotation center O ₁ of the direct drive motor, but the inner diameter center O ₂ of the resolver rotor 55 is relative to the rotation center O _1. Therefore, the thickness of the resolver rotor 55 is continuously changed so as to be eccentric by Δx.
[0016]
The resolver stator 51 is provided with six magnetic poles 52 each constituting an A phase, a B phase, and a C phase at intervals of 120 °, that is, a total of 18 magnetic poles 52. A stator coil 54 wound around a coil bobbin 53 obtained by molding resin is fixed to the magnetic pole 52. With this configuration, when an excitation signal is applied to the common terminal of the stator coil 54, the phase is shifted by 120 ° from each of the A-phase, B-phase, and C-phase stator coils 54 during one revolution of the resolver rotor 55. One cycle of the unipolar resolver signal is output.
[0017]
As shown in FIG. 5, the coil bobbin 53 includes a winding frame portion 53a for winding the stator coil 54, and two flange portions 53b formed to extend outward from the upper and lower outer circumferences of the winding frame portion 53a. A stator coil 54 is uniformly wound around the portion 53a. The magnetic pole 52 is a prismatic body projecting perpendicularly to the outer peripheral surface of the resolver stator 51, and stands upright in the longitudinal direction and has a straight shape without constriction. A coil bobbin 53 in which a stator coil 54 is pre-rolled is inserted into a magnetic pole 52, and a resolver signal of each phase is observed with an oscilloscope in a state where a predetermined AC signal is applied to the stator coil 54, and the balance of the resolver signal of each phase. By adjusting the attachment position of the coil bobbin 53 so as to be removed, the balance mismatch caused by the attachment error of the stator coil 54 can be eliminated. It has been confirmed by experiments of the present inventors that balance can be improved as a whole if balance adjustment can be secured for at least one of the A phase, B phase, and C phase.
[0018]
Since the magnetic pole 52 has a shape with a constant width in the height direction, fine adjustment in the vertical direction is possible even after the coil bobbin 53 is inserted. If the coil bobbin 53 is fixed to the magnetic pole 52 with an adhesive in a state where the balance of each phase is balanced, there can be obtained a resolver for absolute position detection that is consistent among products, that is, compatible. If the air-core coil wound in a conventional manner is directly inserted and fixed to the magnetic pole 52, a minute gap is generated between the coil and the magnetic pole 52, and it is difficult to improve the accuracy of coil attachment. If the coil bobbin 53 is used, the coil is wound around the magnetic pole 52 through a resin having elasticity, so that the generation of such a gap can be suppressed by a suitable pressure-bonding force, and highly accurate positioning can be achieved.
[0019]
FIG. 4 is a cross-sectional view of the relative position detecting resolver 60. As shown in the figure, the inner diameter center O of the resolver stator 61 coincides with the inner diameter center O of the resolver rotor 65, and the reluctance of the gap between the resolver stator 61 and the resolver rotor 65 varies depending on the rotational angle position of the resolver rotor 65. The resolver rotor 65 has a structure in which the fundamental wave component of the reluctance change has a plurality of periods in one rotation of the resolver rotor 65. On the outer peripheral surface of the resolver stator 61, 18 magnetic poles 62 are alternately arranged at equal intervals so that the A phase, the B phase, and the C phase are shifted by an electrical angle of 120 °. A stator coil 64 is wound around 62 via a coil bobbin 63.
[0020]
The number of the magnetic poles 62 may be a multiple of the number of phases (3 in this example), and is not limited to 18. Further, in this example, 24 salient pole-shaped pole teeth formed at a predetermined pitch are formed on the inner peripheral surface of the resolver rotor 65. The number of pole teeth is an integer of the number of teeth of the motor rotor 15. It only needs to be set to 1 /, and is not limited to 24. Further, the resolution of the relative position detecting resolver 60 can be further improved by further electrically subdividing the pole teeth. When an excitation signal is supplied to the common terminal of the stator coil 64, an AC signal of 24 cycles is output as a multipolar resolver signal for each phase while the resolver rotor 65 rotates once.
[0021]
Here, the magnetic pole 62 is a prismatic body protruding perpendicularly to the outer peripheral surface of the resolver stator 61, and has the same shape as the magnetic pole 52 described above in that it has a straight shape without constriction. Therefore, the stator coil 64 is wound around the magnetic pole 62 via the resin-molded coil bobbin 63 in the same manner as described with reference to FIG. 5, thereby enabling high-accuracy positioning and no variation among products. That is, a compatible relative position detecting resolver 60 can be obtained.
[0022]
FIG. 6 is a cross-sectional structure diagram of the resolver cable 41. In the figure, reference numerals 71, 72 and 73 are signal lines of the resolver 60 for detecting the relative position, 71 is an A-phase signal line, 72 is a B-phase signal line, and 73 is a C-phase signal line. 74, 75, and 76 are signal lines of the absolute position detecting resolver 50, 74 is an A-phase signal line, 75 is a B-phase signal line, and 76 is a C-phase signal line. In this way, the signal lines of the relative position detection resolver 60 and the signal line of the absolute position detection resolver 50 are alternately arranged, so that the centers C ₁ , C ₂ , C ₃ of the signal lines 71, 72, 73 are The centers C ₄ , C ₅ , and C ₆ of the signal lines 74, 75, and 76 are adjusted at substantially equal intervals. That is, the triangle connecting C ₁ -C ₂ -C ₃ is a shape close to a regular triangle. Similarly, a triangle connecting the C ₄ -C ₅ -C ₆ is close to a regular triangle shape. Further, since the common line 77 is arranged at the center, the distances between C _{1 to} C ₆ and the center point C ₇ of the common line 77 are all adjusted to be substantially the same interval. With this configuration, it is possible to suppress electrical interference of resolver signals of each phase.
[0023]
FIG. 7 is a cross-sectional structure diagram showing another configuration example of the resolver cable 41. In the figure, reference numerals 81, 82 and 83 denote twisted pair cables in which the signal line and common line of the resolver 60 for detecting the relative position are twisted pairs, 81a is an A phase signal line, 82a is a B phase signal line, 83a. Is a C-phase signal line, and 81b to 83b are common lines. 84, 85, and 86 are twisted pair cables in which the signal line and common line of the resolver 50 for absolute position detection are twisted pairs, 84a is an A phase signal line, 85a is a B phase signal line, and 86a is C. The phase signal lines 84b to 86b are common lines. In this way, the signal lines of the relative position detection resolver 60 and the signal line of the absolute position detection resolver 50 are alternately arranged, so that the centers C ₁ , C ₂ , C ₃ of the signal lines 81, 82, 83 are The centers C ₄ , C ₅ , and C ₆ of the signal lines 84, 85, and 86 are adjusted at substantially equal intervals. That is, the triangle connecting C ₁ -C ₂ -C ₃ is a shape close to a regular triangle. Similarly, the triangle connecting C ₄ -C ₅ -C ₆ is a shape close to a regular triangle. Moreover, since each is a twisted pair cable, the distance between each signal line and the common line can be made equal. With this configuration, it is possible to suppress electrical interference of resolver signals of each phase.
[0024]
In addition to adjusting the position of the coil bobbin, for example, a variable resistor or the like may be connected to each coil so that fine adjustment can be performed. Further, the material of the coil bobbin is not limited to resin, but may be other material as long as it is a non-magnetic material that is highly elastic and has an appropriate pressure bonding force.
[0025]
【The invention's effect】
According to the present invention, the annular stator has columnar magnetic poles arranged in the circumferential direction, and the coil position can be freely positioned by inserting the stator coil wound around the coil bobbin into the magnetic pole. Therefore, the resolver coil position can be finely adjusted, and a compatible direct drive motor system can be provided by suppressing variations between direct drive motors. In addition, by making the distance between the signal lines of the resolver cable and the distance between the signal line and the common line substantially constant, it is possible to suppress the electrical interference of the resolver signal and provide a compatible direct drive motor system. can do.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a direct drive motor system.
FIG. 2 is a sectional structural view of a direct drive motor.
FIG. 3 is a cross-sectional structure diagram of an absolute position detection resolver.
FIG. 4 is a cross-sectional view of a relative position detecting resolver.
FIG. 5 is an explanatory diagram of positioning of a stator coil.
FIG. 6 is a sectional structural view of a resolver cable.
FIG. 7 is a sectional structural view of a resolver cable.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Direct drive motor, 11 ... Rotating shaft, 20 ... Drive unit, 30 ... Controller, 41 ... Resolver cable, 50 ... Resolver for absolute position detection, 51 ... Resolver stator, 52 ... Magnetic pole, 53 ... Bobbin, 54 ... Stator coil, 60 ... Resolver for detecting relative position, 61 ... Resolver stator, 62 ... Magnetic pole, 63 ... Bobbin, 64 ... Stator coil

Claims (5)

A single pole resolver in which the fundamental wave component of reluctance in the gap between the first rotor and the first annular stator becomes one cycle by the rotation of the first rotor, and the second rotor by the rotation of the second rotor. And a multipolar resolver in which the fundamental wave component of reluctance in the gap between the second annular stator has a plurality of periods, and a direct drive motor that outputs a multiphase resolver signal from each resolver, A drive unit that outputs an excitation current for driving the direct drive motor based on the output multiphase resolver signal, and a resolver cable that transmits the multiphase resolver signal output from the direct drive motor to the drive unit. In the direct drive motor system, the first and second annular slides Over data has a pole columnar provided around the circumferential direction, the magnetic pole type-wound stator coil bobbin, positionable freely inserted and attached, each phase of the resolver of the polyphase resolver signal A direct drive motor system that adjusts the coil position and bonds it so that the signal is balanced . A single pole resolver in which the fundamental wave component of reluctance in the gap between the first rotor and the first annular stator becomes one cycle by the rotation of the first rotor, and the second rotor by the rotation of the second rotor. And a multipolar resolver in which the fundamental wave component of reluctance in the gap between the second annular stator has a plurality of periods, and a direct drive motor that outputs a multiphase resolver signal from each resolver, A drive unit that outputs an excitation current for driving the direct drive motor based on the output multiphase resolver signal, and a resolver cable that transmits the multiphase resolver signal output from the direct drive motor to the drive unit. The first and second annular stators have columnar magnetic poles arranged in the circumferential direction. And a method of manufacturing a direct drive motor system formed of a fixed mold-wound stator coil bobbin to the magnetic pole,
Inserting the stator coil into the magnetic pole ;
Adjusting the coil position of the stator coil so that the resolver signal of each phase of the multiphase resolver signal is balanced;
Bonding the stator coil to the magnetic pole;
A method of manufacturing a direct drive motor system, comprising:   2. The direct drive motor system according to claim 1, wherein the resolver cable has a substantially constant distance between signal lines of each phase of a multiphase resolver signal and a distance between each signal line and a common line. The unipolar resolver and the multipolar resolver each have a three-phase resolver signal,
  The resolver cable is
  A first unipolar resolver signal line, a second unipolar resolver signal line and a third unipolar resolver signal line which are signal lines of the unipolar resolver;
  A first multipolar resolver signal line, a second multipolar resolver signal line, and a third multipolar resolver signal line, which are signal lines of the multipolar resolver,
  The signal lines of the monopolar resolver and the signal lines of the multipolar resolver are alternately arranged, and the centers of these signal lines are arranged at almost equal intervals.
The direct drive motor system according to claim 1, wherein: The unipolar resolver and the multipolar resolver each have a three-phase resolver signal,
  The resolver cable is
  A first unipolar resolver signal line, a second unipolar resolver signal line and a third unipolar resolver signal line which are signal lines of the unipolar resolver;
  A first multipolar resolver signal line, a second multipolar resolver signal line, and a third multipolar resolver signal line that are signal lines of the multipolar resolver;
  Has 6 common lines,
  2. The signal line of the monopolar resolver and the signal line of the multipolar resolver are alternately arranged, and these signal lines constitute the common line and a twisted pair cable, respectively. Direct drive motor system described in 1.

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