JP2004140965A - Detector for rotor field position of rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detector for a rotor field position capable of detecting the position of a rotor field with high accuracy while reducing a cost. <P>SOLUTION: The detector is provided with a stator 2 wound with a coil in the circumferential direction, a rotor 3 that is arranged at the internal periphery of the stator 2 and comprises a plurality of torque magnets 3c that are coupled to a rotating shaft 3a in a rotative manner relative to the stator 2 in the circumferential direction, a non-magnetic plate 4 that is arranged at the end face in the rotative axial direction of the rotor 3 and suppresses the magnetic flux of the torque magnet 3c to leak out in the rotative axial direction, a plurality of position detecting magnets 12 arranged at the side opposed to the rotor 3 of the non-magnetic plate 4, magnetic pieces 10 that correspond to the plurality of position detecting magnets 12, and magnetized by the position detecting magnets 12, and a magnetic pole position detection means 5 that responds to a magnetic pole appearing at the magnetic piece 10 and outputs a signal of a rotor magnetic pole position. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotor magnetic pole position detecting device of a rotating electrical machine using a magnetic position sensor that outputs a rotor magnetic pole position signal in response to a magnetic pole appearing on a magnetic piece.
[0002]
[Prior art]
To control the rotation of rotating electric machines (motors (motors), generators (generators), generators and motors, etc.) that are not provided with commutators, brushes, etc., the position of the rotating rotor must always be accurate. Need to be detected. For example, in Patent Document 1, the position of a rotation position detection disk having the same rotation center as the rotor and the outer peripheral surface magnetized with the same number of magnetic poles as the rotor is detected by a rotation position signal generator constituted by a Hall IC. Is disclosed.
[0003]
[Patent Document 1]
JP-A-11-215881
[Problems to be solved by the invention]
However, in the above-described related art, the detection accuracy of the rotor magnetic pole position is determined by the magnetization accuracy with respect to the rotational position detection disk, so that it is difficult to increase the detection accuracy.
[0005]
The present invention has been made in view of such a conventional problem, and provides a rotor magnetic pole position detecting device of a rotating electrical machine that can accurately detect a rotor magnetic pole position while keeping costs low. The purpose is.
[0006]
[Means for Solving the Problems]
The present invention solves the above problem by the following means. Note that, for easy understanding, reference numerals corresponding to the embodiments of the present invention are given, but the present invention is not limited thereto.
[0007]
The present invention relates to a stator (2) having a coil wound in the circumferential direction, a stator (2) arranged on the inner periphery of the stator (2), connected to a rotating shaft (3a), and A rotor (3) rotatable and having a plurality of torque magnets (3c) in a circumferential direction; and a rotor (3) disposed on an end face in a rotation axis direction of the rotor (3), and a magnetic flux of the torque magnet (3c) rotates. A non-magnetic plate (4) for reducing leakage in the axial direction; and a plurality of position detecting magnets (12) arranged on a surface of the non-magnetic plate (4) opposite to a surface facing the rotor (3). ), Corresponding to the plurality of position detecting magnets (12) and being magnetized by the position detecting magnets (12), and a magnetic pole appearing on the magnetic member (10). Magnetic pole position detecting means (5) for outputting a rotor magnetic pole position signal by The features.
[0008]
[Action / Effect]
According to the present invention, the position detecting magnet and the magnetic piece are arranged on the nonmagnetic plate that rotates integrally with the rotor, and the magnetic pole position of the rotor is detected from the magnetic poles appearing on the magnetic piece. The accuracy of detecting the magnetic pole position is improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings and the like.
[0010]
1 and 2 are general configuration diagrams showing a motor (permanent magnet type synchronous motor) to which the magnetic pole position detecting device of the present invention is applied. 1 is a cross section taken along line II of FIG. 2, and FIG. 2 is a cross section taken along line II-II of FIG.
[0011]
The motor M includes a case 1, a stator 2, and a rotor 3.
[0012]
The case 1 has a cylindrical member 1a and a side plate 1b.
[0013]
The cylindrical member 1a is a cylindrical member having both ends opened, and the stator 2 is disposed on the inner periphery thereof.
[0014]
The side plate 1b is a member for closing the openings at both ends in the axial direction of the cylindrical member 1a. The side plate 1b is attached to the cylindrical member 1a with bolts (not shown). The side plate 1b is provided with a bearing 6 that rotatably supports a rotation shaft 3a (described later) of the rotor 3.
[0015]
The stator 2 includes a stator core 2a formed by laminating many electromagnetic steel plates, and a stator coil 2b. The stator core 2a has a ring-shaped back core portion and a tooth portion projecting radially inward from the back core portion. The stator coil 2b is wound around the teeth portion in a concentrated manner. The twelve stator coils 2b wound around the twelve teeth on the entire circumference are divided into three groups (U, V, W), each group including four coils. To each group, alternating currents (U-phase current, V-phase current, W-phase current) whose phases are different by 120 ° are supplied. That is, this motor is driven by three-phase alternating current. The stator 2 is press-fitted and fixed inside the cylindrical member 1 a of the case 1.
[0016]
The rotor 3 is arranged inside the stator 2. The rotor 3 has a rotor rotating shaft 3a and a cylindrical rotor core 3b formed by laminating a number of electromagnetic steel sheets.
[0017]
Both ends of the rotating shaft 3a are supported by the side plate 1b via bearings 6, and are rotatable.
[0018]
A magnet insertion hole is formed in the rotor core 3b, into which the torque magnet 3c is inserted and fixed. The torque magnets 3c are magnetized in the thickness direction (substantially radial direction of the rotor 3), and eight magnets are arranged in the circumferential direction so that the poles on the outer peripheral side of the rotor are alternately arranged. Therefore, this rotor 3 is a rotor having four pole pairs.
[0019]
End plates 4 are provided on both axial end surfaces of the rotor core 3b. The end plate 4 is a non-magnetic plate for reducing the leakage of the magnetic flux of the torque magnet 3c in the axial direction, and may be, for example, a stainless plate. The end plate 4 has a ring-shaped groove 4a for accommodating the position detecting magnet 12. The depth of the ring-shaped groove 4a is the same or substantially the same as the thickness of the position detecting magnet 12. Therefore, the position detecting magnet 12 arranged in the ring-shaped groove 4a is pressed against the end plate 4 by the magnetic piece 10 arranged thereon as described later, and the axial movement is restricted. The position detecting magnets 12 are magnetized in the thickness direction (the axial direction of the rotor 3), and eight magnets are arranged in the ring-shaped groove 4a at a constant angle (mechanical angle 45 °) so that the poles on the rotor end face alternate. Have been. Since the rotor 3 is a four-pole pair rotor, the position detecting magnets 12 are arranged every electrical angle of 180 °.
[0020]
Further, on the end plate 4, magnetic pieces 10 corresponding to the respective position detecting magnets 12 are fixed. The magnetic body piece 10 is, for example, an iron piece. The width of the magnetic piece 10 (dimension in the rotor radial direction) is larger than the width of the position detecting magnet 12 and the ring-shaped groove 4a, and is arranged so as to cover the corresponding position detecting magnet 12. A slight gap (for example, a circumferential width of about 1 ° in mechanical angle) is provided between adjacent magnetic pieces 10. Further, the magnetic piece 10 is accurately positioned with respect to the end plate 4 by the non-magnetic fixing pin 11 penetrating the end plate 4, the magnetic piece 10, and the position detecting magnet 12. Further, each magnetic body piece 10 is fixed to the end plate 4 by spot welding P at four places around the magnetic body piece 10. The movement of the position detecting magnet 12 in the radial direction and the circumferential direction is restricted by the fixing pin 11. The axial movement of the position detecting magnet 12 is regulated by the magnetic piece 10. Therefore, the position detecting magnet 12 is fixed to the end plate 4. The position detection magnet 12 does not need to be firmly fixed, but may be simply fixed with an adhesive or the like in order to prevent rattling. Since the magnetic piece 10 is wider than the position detecting magnet 12, the position of the spot welding P can be kept away from the position detecting magnet 12, and the position detecting magnet 12 is demagnetized due to a rise in temperature during execution of the spot welding. Can be avoided.
[0021]
On the other hand, a magnetic pole position sensor 5 using a latch output type Hall IC sensor is attached to the side plate 1b constituting the case 1. The magnetic pole position sensor 5 is a magnetic pole position detecting unit that outputs a rotor magnetic pole position signal in response to a magnetic pole appearing on the magnetic piece 10. The magnetic pole position sensor 5 is composed of three sensors, a U-phase sensor 5u, a V-phase sensor 5v, and a W-phase sensor 5w. °). Each sensor outputs a high-level or low-level signal according to the polarity of the magnetic flux on the opposing magnetic piece 10.
[0022]
Since the magnetic flux is largely disturbed in the vicinity of the fixed pin 11, the magnetic pole position sensor 5 may be disposed away from the fixed pin 11 so that the disturbance does not affect the magnetic pole position sensor 5 when the rotor 3 rotates. Specifically, the magnetic pole position sensor 5 determines that the distance from the rotation shaft 3a is different from the distance between the fixed pin 11 and the rotation shaft 3a, in other words, when viewed from the rotor rotation axis direction (FIG. 2). The magnetic pole position sensor 5 may be disposed at a predetermined distance or more from the fixed pin 11 so that the magnetic pole position sensor 5 does not overlap the locus of the fixed pin 11 when the rotor 3 rotates. More specifically, when the magnetic pole position sensor 5 overlaps with the phase where the fixed pin 11 is installed, the signal of the magnetic pole position sensor 5 is separated by a distance that is not inverted with respect to the neighboring phase. It is good to arrange.
[0023]
FIG. 3 is a diagram showing an output signal with respect to an electrical angle of each magnetic pole position sensor.
[0024]
The outputs of the three sensors (U-phase sensor 5u, V-phase sensor 5v, W-phase sensor 5w) change as shown in FIG. 3 according to the rotor magnetic pole position (rotor rotation phase). Therefore, the rotor magnetic pole position can be detected with a resolution of 60 electrical degrees from the combination of the three signals.
[0025]
According to the present embodiment, the following effects are obtained.
[0026]
In order to increase the detection accuracy of the rotor magnetic pole position, for example, a method of using a rotation position detection disk on which a plurality of detection magnets magnetized in advance are attached is considered. However, in such a case, the dimensional accuracy of each detection magnet must be increased. However, in general, the material (eg, ferrite) used as the material of the permanent magnet is difficult to process, and it is difficult to increase the shape accuracy.
[0027]
However, in the present embodiment, the end plate 4 is fixed to the axial end face of the rotor core 3b, the position detecting magnet 12 is disposed in the ring-shaped groove 4a, and the magnetic piece 10 is further disposed. Are detected by the magnetic pole position sensor 5. Therefore, according to the present embodiment, the accuracy of detecting the magnetic pole position of the rotor can be improved by improving the molding accuracy and the mounting accuracy of the magnetic piece 10.
[0028]
Further, in the present embodiment, since an iron piece or the like can be used as the magnetic material piece 10, molding is easy, and shape accuracy can be improved without incurring a significant increase in cost.
[0029]
Further, in the present embodiment, the magnetic piece 10 is welded after being positioned with respect to the end plate 4 by the fixing pin 11. Therefore, the magnetic piece 10 can be attached to the end plate 4 with high positional accuracy.
[0030]
As described above, according to the present embodiment, it is possible to improve the molding precision and the mounting precision of the magnetic piece while keeping the cost inexpensive, thereby reducing the cost and detecting the magnetic pole position of the rotor. It is possible to achieve both improved accuracy.
[0031]
In addition, since the rotor of the rotating electric machine rotates at high speed, it is important to fix the position detecting magnet so as not to fall off during the rotation. However, it was difficult to firmly fix the permanent magnet itself directly to the end plate. However, according to the present embodiment, the position detecting magnets 12 are arranged in the ring-shaped grooves 4 a of the end plate 4, and the magnetic material pieces 10 are covered therefrom and fixed to the end plate 4 by welding. Therefore, the position detecting magnet 12 can be firmly fixed. Further, since the magnetic piece 10 is wider than the position detecting magnet 12, the welding position can be kept away from the position detecting magnet 12, and the temperature rise of the position detecting magnet 12 during welding can be prevented. Demagnetization due to thermal effects can be avoided.
[0032]
Furthermore, since the depth of the ring-shaped groove 4a is the same or almost the same as the thickness of the position detecting magnet 12, the position of the position detecting magnet 12 in the axial direction is fixed by the magnetic piece 10 disposed thereon. As a result, it has become possible to withstand high-speed rotation of the rotor.
[0033]
Without being limited to the embodiments described above, various modifications and changes can be made within the scope of the technical idea, and it is apparent that they are equivalent to the present invention.
[0034]
For example, in the above embodiment, a motor (motor) is described as an example of the rotating electric machine, but it goes without saying that a generator (generator) or a generator / motor may be used.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a motor to which a magnetic pole position detecting device according to the present invention is applied, and is a cross-sectional view seen from a direction orthogonal to a rotation axis.
FIG. 2 is an overall configuration diagram showing a motor to which the magnetic pole position detecting device of the present invention is applied, and is a cross-sectional view as viewed from a rotation axis direction.
FIG. 3 is a diagram showing an output signal with respect to an electrical angle of each magnetic pole position sensor.
[Explanation of symbols]
M Motor 1 Case 2 Stator 3 Rotor 3a Rotating shaft 3b Rotor core 3c Torque magnet 4 End plate (non-magnetic plate)
5 Magnetic pole position sensor (magnetic pole position detecting means)
5u U-phase sensor 5v V-phase sensor 5w W-phase sensor 10 Magnetic piece 11 Fixed pin 12 Position detecting magnet

Claims (8)

A stator wound with coils in the circumferential direction;
A rotor arranged on the inner periphery of the stator, connected to a rotating shaft, rotatable relative to the stator, and having a plurality of torque magnets in a circumferential direction;
A non-magnetic plate that is disposed on the rotation axis direction end face of the rotor and reduces leakage of the magnetic flux of the torque magnet in the rotation axis direction;
A plurality of position detection magnets disposed on the surface of the non-magnetic plate opposite to the surface facing the rotor,
A magnetic piece corresponding to the plurality of position detection magnets and magnetized by the position detection magnet,
Magnetic pole position detecting means for outputting a rotor magnetic pole position signal in response to a magnetic pole appearing on the magnetic piece;
A rotor magnetic pole position detection device for a rotating electric machine comprising: 2. The rotor magnetic pole position of the rotating electric machine according to claim 1, wherein the plurality of position detection magnets are arranged so as to be adjacent to each other in an opposite magnetization direction at an electrical angle of 180 °. 3. Detection device. The position detection magnet is disposed in a groove formed in the nonmagnetic plate,
The magnetic piece is disposed on the position detecting magnet,
The rotor magnetic pole position detecting device for a rotating electric machine according to claim 1 or 2, wherein: The magnetic piece, the width of which is wider than the width of the groove, is disposed across the groove, and is fixed to the non-magnetic plate.
4. The rotor magnetic pole position detecting device for a rotating electric machine according to claim 3, wherein: The depth of the groove of the non-magnetic plate is the same or substantially the same as the thickness of the position detecting magnet,
The rotor magnetic pole position detecting device for a rotating electric machine according to claim 3 or 4, wherein: A fixing pin that penetrates at least the position detection magnet and fixes the position detection magnet and the magnetic piece to the nonmagnetic plate,
The rotor magnetic pole position detecting device for a rotating electrical machine according to any one of claims 1 to 5, wherein: The magnetic pole position detecting means overlaps the trajectory of the fixed pin when the rotor rotates when viewed from the rotor rotation axis direction so that the distance from the rotation axis is different from the distance between the fixed pin and the rotation axis. The rotor magnetic pole position detecting device for a rotating electric machine according to claim 6, wherein the rotor magnetic pole position detecting device is arranged at a position separated by a predetermined distance or more. The predetermined distance is a distance at which the signal of the magnetic pole position detecting means does not reverse with respect to a phase in the vicinity thereof when the magnetic pole position detecting means overlaps with the phase where the fixing pin is provided. ,
The rotor magnetic pole position detecting device for a rotating electric machine according to claim 7, wherein:

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