JP2010025700A - Fixed structure of resolver rotor and brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixed structure of a resolver rotor that suppresses nonuniform deformation of the circumferential direction of the outside detection surface accompanying with press fit to a rotation shaft, and contributes to improvement in detection performance of the resolver. <P>SOLUTION: In this fixed structure, a press fit section 5a and a non-press fit section 5b are arranged axially in a fixed part of the rotation shaft 5 to the resolver rotor 21. The resolver rotor 21 is press-fitted to the press fit section 5a of the rotation shaft 5 so that the non-press fit section 5b is included in a part of the axial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure for fixing a variable reluctance resolver rotor to a rotating shaft, and a brushless motor provided with the resolver.

Conventionally, as a variable reluctance type (VR type) resolver rotor, for example, one described in Patent Document 1 is known. The resolver rotor is formed by laminating a plurality of core sheets (magnetic steel plates), and the gap permeance between the outer detection surface and the resolver stator is relative to the rotation angle of the resolver rotor (rotary shaft). It has a non-circular shape that changes in a sinusoidal shape. Such a resolver rotor is generally fixed to a rotating shaft by press fitting.
JP 2003-287441 A

  By the way, since it is necessary to position the resolver rotor with the rotating shaft, in Patent Document 1, a shaft fixing hole having a D-shaped cross section is formed at the center of the resolver rotor, and the fixing portion of the resolver rotor of the rotating shaft is shown in cross section. It is formed in a D-shape, and the rotary shaft is press-fitted into the shaft fixing hole to fix the resolver rotor.

  However, since the shaft fixing hole provided in the resolver rotor has a D-shaped cross section and is non-circular, the reaction force of the pressure contact force from the rotating shaft does not act uniformly in the circumferential direction at the peripheral portion of the shaft fixing hole. As a result, the outer detection surface of the resolver rotor is deformed unevenly in the circumferential direction. Since the outer detection surface of the resolver rotor is formed in a highly accurate shape related to the detection of the rotation angle, if such uneven deformation in the circumferential direction occurs, the rotation angle signal generated by the resolver stator Harmonic components that coincide with the number of slots in the resolver stator, which cause waveform distortion, are promoted and may significantly affect detection performance.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to suppress uneven deformation in the circumferential direction of the outer detection surface due to press-fitting into the rotating shaft, and to improve the detection performance of the resolver. It is an object of the present invention to provide a resolver rotor fixing structure and a brushless motor that can contribute to the above.

  In order to solve the above-mentioned problem, the invention according to claim 1 is formed by laminating and integrating a plurality of core sheets, and has an outer detection surface on the radially outer side and a non-circular shape by a positioning portion at the center portion. A variable reluctance type resolver rotor having a fixed shaft hole is used, and is a fixed structure of a resolver rotor that is press-fitted and fixed to a rotating shaft by the fixed shaft hole, and includes a rotating shaft and the resolver rotor. The fixed portion includes a press-fit portion and a non-press-fit portion arranged in the axial direction, and the resolver rotor is press-fitted and fixed to the rotating shaft at the press-fit portion so that the non-press-fit portion is included in a part of the axial direction. The gist of this is

  In the present invention, the press-fitting part and the non-press-fitted part are arranged in the axial direction in the fixed part of the rotating shaft and the resolver rotor, and the resolver rotor has the press-fitted part so that the non-fitted part is included in a part of the axial direction Is press-fitted and fixed to the rotating shaft. In other words, the non-press-fit part provided in a part in the axial direction of the fixed part between the rotating shaft and the resolver rotor does not receive the reaction force of the pressure contact force from the rotating shaft due to the press-fitting of the resolver rotor. Deformation does not occur, and this also averages the non-uniformity in the circumferential direction of the deformation of the outer detection surface at the press-fit portion. Thereby, it can contribute to the improvement of the detection performance of a resolver.

  According to a second aspect of the present invention, in the fixing structure of the resolver rotor according to the first aspect, the rotary shaft includes the press-fit portion and the non-press-fit portion due to a reduced diameter. To do.

  In this invention, since the press-fit portion and the non-press-fit portion due to the reduced diameter are formed on the rotation shaft, the resolver rotor has the same shape in the axial direction, and in particular, this resolver rotor formed by laminating a plurality of core sheets has the same shape. The core sheet can be used.

  According to a third aspect of the present invention, in the fixing structure of the resolver rotor according to the first or second aspect, the resolver rotor is press-fitted and fixed at the press-fitted portions on both axial sides sandwiching the non-press-fitted portion. This is the gist.

  In the present invention, the resolver rotor is press-fitted and fixed at the press-fitting portions on both axial sides across the non-press-fitted portion. That is, since the axially central portion of the outer detection surface of the resolver rotor, that is, the portion that has a large influence on the detection of the rotational angle of the resolver corresponds to the non-pressed portion, deformation due to the press fitting of the resolver rotor does not occur. This can contribute to further improvement in the detection performance of the resolver. Further, since the resolver rotor is fixed to the rotating shaft on both axial sides thereof, stable fixing is possible.

  According to a fourth aspect of the present invention, in the fixing structure of the resolver rotor according to any one of the first to third aspects, the resolver rotor is formed by the non-press-fitted portion and the rotor and the rotating shaft. The gist is that resin is filled in and fixed between the gaps.

  In the present invention, the resolver rotor is fixed by filling a resin in a gap between the rotor and the rotation shaft formed by the non-press-fit portion. In other words, the resin filled in the gap of the non-press-fit portion improves the fixing force with respect to the rotating shaft of the resolver rotor and absorbs vibrations generated in the resolver rotor.

  According to a fifth aspect of the present invention, in the fixing structure of the resolver rotor according to the first or second aspect, the positioning portion is inserted into the concave portion that is a positioning concave portion that opens into the shaft fixing hole, and is closely adhered in the circumferential direction. The gist includes an engaging portion that engages and a collar member that is non-press-fitted into the shaft fixing hole of the resolver rotor and is press-fitted and fixed to the rotation shaft of the non-press-fitted portion.

  According to the present invention, a collar member is provided that is press-fitted and fixed to the rotation shaft of the non-press-fit portion and is non-press-fitted into the shaft fixing hole of the resolver rotor, and an engaging portion provided on the member serves as a positioning portion of the resolver rotor. It is inserted into the positioning recess and closely engaged in the circumferential direction. As a result, the anti-spinning force of the resolver rotor is prevented by the close engagement in the circumferential direction between the engaging portion of the collar member and the positioning recess of the resolver rotor without the collar member affecting the deformation of the outer detection surface of the resolver rotor. Will improve.

  A sixth aspect of the present invention is a resolver rotor that is press-fitted and fixed to a rotating shaft of a motor using the fixing structure according to any one of the first to fifth aspects, and a resolver stator that is disposed radially outside thereof. Is a brushless motor on which a variable reluctance type resolver equipped with is mounted.

  In the present invention, the resolver rotor is press-fitted and fixed to the rotating shaft of the motor by using the fixing structure described in the above claims, and the resolver detection performance is improved. Therefore, a resolver-mounted brushless motor excellent in rotation angle detection is provided. it can.

  According to the present invention, there is provided a resolver rotor fixing structure and a brushless motor that can suppress non-uniform deformation in the circumferential direction of the outer detection surface due to press-fitting into a rotating shaft and contribute to improvement of the detection performance of the resolver. can do.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a brushless motor 1 equipped with a variable reluctance type (VR type) resolver in the present embodiment. The brushless motor 1 is assembled in a vehicular electric power steering apparatus whose main purpose is to assist a driver's steering operation, for example.

  As shown in FIG. 1, the brushless motor 1 includes an annular stator 4 in which a motor winding 2 is wound around a plurality of teeth 3 a of a stator core 3, and a rotating shaft 5 that is disposed inside the stator 4. A rotor 6 that rotates integrally and a VR resolver 7 that detects a rotation angle of the rotor 6 are provided.

  A motor case 10 of the brushless motor 1 includes a yoke housing 11 formed in a bottomed cylindrical shape and an end plate 12 that closes an opening 11 a of the yoke housing 11, and the stator 4 has an inner periphery of the yoke housing 11. It is fixed to the surface. The stator 4 generates a rotating magnetic field when three-phase (U, V, W phase) driving power is supplied to the motor winding 2.

  The rotor 6 has a rotating shaft 5 rotatably supported by bearings 13 and 14 provided on the bottom 11 b of the yoke housing 11 and the end plate 12, and is disposed inside the stator 4. The rotor 6 has a plurality of magnets (not shown) inside a cylindrical cover 6a for preventing magnet scattering. The rotor 6 rotates under the influence of a rotating magnetic field generated in the stator 4.

  As shown in FIG. 2, the resolver 7 is an annular resolver rotor 21 that is press-fitted into the rotating shaft 5 and fixed so as to rotate integrally with the rotating shaft 5 (rotor 6), and a radially outer side of the resolver rotor 21. And an annular resolver stator 22.

  As shown in FIGS. 3A and 3B, the resolver rotor 21 is formed by laminating a plurality of core sheets 21x made of magnetic steel plates having the same shape, and a plurality (seven) salient poles projecting radially outward. The unit 31 is provided. These salient pole portions 31 are arranged at equal angular intervals in the circumferential direction, and have a substantially arc-shaped outer detection surface 31a that is line-symmetric with respect to the bisector of the central angle.

  The resolver rotor 21 has a substantially circular shaft fixing hole 32 for fixing to the rotation shaft 5 at the center, and the circumferential direction of any one of the plurality of salient pole portions 31. It has a rectangular positioning recess 33 (positioning portion) that opens toward the shaft fixing hole 32 at the angular position of the center portion. The positioning recess 33 has a groove shape in which the recesses 33x formed in each core sheet 21x are aligned in the axial direction, thereby penetrating in the axial direction. The positioning recess 33 is for positioning the resolver rotor 21 in the circumferential direction with respect to the rotor 6. For example, a jig or the like is inserted between the rotors 6, 21, and each salient pole portion 31 of the resolver rotor 21. It is used for circumferential positioning of the rotor 6 with the permanent magnet.

  The resolver rotor 21 has press-fit portions 34 on both sides in the circumferential direction of the positioning recess 33 at the inner peripheral edge of the shaft fixing hole 32, and the center in the circumferential direction of the other salient pole portion 31 that does not have the recess 33. One press-fit portion 35 is provided at each angular position of the portion. When the resolver rotor 21 is press-fitted into the rotary shaft 5, the press-fit portions 34 and 35 are pressed against the outer peripheral surface (circumferential surface) of the rotary shaft 5, so that the resolver rotor 21 is fixed to the rotary shaft 5.

  Further, the resolver rotor 21 has circular caulking portions 36 respectively disposed at equidistant positions radially inward from the outer detection surface 31a at the angular position of the center portion in the circumferential direction of each salient pole portion 31. These caulking portions 36 are formed by being extruded from one side surface to the other side surface of each core sheet 21x, and the convex portion of the caulking portion 36 of one adjacent core sheet 21x is the concave portion of the caulking portion 36 of the other core sheet 21x. The plurality of core sheets 21x are laminated in the axial direction and fixed integrally. And it is press-fitted with respect to the rotating shaft 5 by the resolver rotor 21 comprised by integrating the several core sheet | seat 21x.

  Here, in the fixed portion of the rotary shaft 5 to the resolver rotor 21, in this embodiment, both axial sides of the fixed portion are the press-fit portions 5a, and the non-press-fit portion is formed by a reduced diameter between the press-fit portions 5a. 5b is configured. Incidentally, the shape of the non-press-fit portion 5b having a reduced diameter is exaggerated. The resolver rotor 21 is fixed to each press-fit portion 5a by press-fitting by the press-fit portions 34 and 35 so as to straddle the non-press-fit portion 5b in the axial direction.

  That is, when the resolver rotor 21 is press-fitted into the rotating shaft 5, the distortion dimension amount that appears on the outer detection surface 31 a of each salient pole portion 31 due to the influence of the positioning recess 33 provided in a part of the shaft fixing hole 32 in the circumferential direction. There will be a difference. However, by providing the non-press-fit portion 5b in a part in the axial direction of the fixed portion of the resolver rotor 21 as in the present embodiment, this portion receives the reaction force of the pressure contact force from the rotary shaft 5 due to the press-fit of the resolver rotor 21. Therefore, the outer detection surface 31a of each salient pole portion 31 is not deformed, and this averages the unevenness of the deformation of the outer detection surface 31a of the salient pole portion 31 in the press-fit portion 5a. In other words, the axial length of the non-press-fit portion 5b is set to a suitable length in consideration of the fixing force of the resolver rotor 21 and the deformation amount of the outer detection surface 31a. In this way, the deformation of the outer detection surfaces 31a of all the salient pole portions 31 of the resolver rotor 21 is made substantially equal, and the detection performance of the resolver 7 is improved.

  As shown in FIGS. 1 and 2, the resolver stator 22 is formed by laminating a plurality of core sheets 22x made of magnetic steel plates having the same shape, and a resolver stator core 23 having a plurality (ten) teeth 23a, and a resin And a resolver winding 25 wound around a tooth 23a via an insulator 24. The resolver winding 25 has a single-phase excitation winding to which an excitation voltage is applied, and an output signal (rotation angle signal) having a different phase according to the rotation of the resolver rotor 21 based on the excitation of the excitation winding. It consists of two-phase output windings that output, each wound around a tooth 23a at a predetermined position. The resolver stator 22 is fixed to the end plate 12 with a fixing plate 15 and a mounting screw 16.

  The resolver stator 22 is integrally provided with a resolver connector 26. The resolver winding 25 is electrically connected to a control device (not shown) provided outside by connecting the resolver connector 26 to the connection connector 27a of the signal wiring 27 extending from the outside. The control device detects the rotational position of the resolver rotor 21, that is, the rotor 6 of the motor 1, based on the output signal obtained from the output winding while exciting the excitation winding of the resolver winding 25, and the stator 4. A three-phase drive power supply to be supplied to the (motor winding 2) is generated.

Next, characteristic effects of the present embodiment will be described.
(1) In this embodiment, the press-fitting part 5a and the non-press-fitted part 5b are arranged in the axial direction in the fixed part of the rotating shaft 5 with the resolver rotor 21, and the non-press-fitted part 5b has a shaft. It is press-fitted and fixed to the press-fitted portion 5a of the rotary shaft 5 so as to be included in a part of the direction. That is, the non-press-fit portion 5b provided at a part in the axial direction of the fixed portion of the rotating shaft 5 with the resolver rotor 21 does not receive the reaction force of the pressure contact force from the rotating shaft 5 due to the press-fitting of the resolver rotor 21. No deformation occurs in the outer side detection surface 31a of 21, and this makes it possible to average the non-uniformity in the circumferential direction of the deformation of the outer detection surface 31a in the press-fit portion 5a. Therefore, in the output signal (rotation angle signal) generated by the resolver 7 relating to the detection of the rotation angle of the rotor 6 of the motor 1, harmonics that match the number of slots (10) of the resolver stator 22 that cause the waveform distortion. The component (10th harmonic component) can be suppressed, and the detection performance of the resolver 7 can be improved. Thereby, the brushless motor 1 equipped with the resolver 7 excellent in rotation angle detection can be configured, and as a result, the brushless motor 1 with low vibration and low noise can be configured.

  (2) In the present embodiment, since one positioning recess 33 of the resolver rotor 21 is provided in the circumferential direction, compared to an embodiment in which a plurality of the recesses 33 are provided in the circumferential direction, when fixing to the rotating shaft 5. Can be prevented from escaping to the concave portion 33 side, and the fixing force at the time of fixing between the core sheets 21x by the caulking portion 36 can also be prevented from escaping to the concave portion 33 side, thereby strengthening the fixation. be able to. On the other hand, since one positioning recess 33 of the resolver rotor 21 is provided in the circumferential direction, the deformation of the outer detection surface 31a of each salient pole portion 31 is likely to be uneven. large.

  (3) In this embodiment, since the press-fitting part 5a and the non-press-fitted part 5b with a reduced diameter are formed on the rotary shaft 5, the resolver rotor 21 has the same shape in the axial direction, that is, a plurality of core sheets 21x are laminated. Thus, the resolver rotor 21 of the present embodiment can use the core sheet 21x having the same shape, which can contribute to ease of manufacturing and cost reduction of the resolver rotor 21.

  (4) In the present embodiment, the resolver rotor 21 is press-fitted and fixed to the press-fitted portions 5 a on both sides in the axial direction across the non-press-fitted portion 5 b of the rotating shaft 5. That is, the axially central portion of the outer detection surface 31a of the resolver rotor 21, that is, the portion having a large influence on the rotation angle detection of the resolver 7 corresponds to the non-pressed portion 5b, so that the deformation due to the press fitting of the resolver rotor 21 is performed. Since it does not occur, the detection performance of the resolver 7 can be further improved. In addition, since the resolver rotor 21 is fixed to the rotary shaft 5 on both axial sides thereof, stable fixing can be achieved.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, a gap is formed between the non-press-fitted portion 5b of the rotating shaft 5 and the inner peripheral edge of the shaft fixing hole 32 of the resolver rotor 21. For example, as shown in FIG. The gap 40 may be filled with the resin 40. That is, the resin 40 filled in the gap S of the non-press-fit portion 5b improves the fixing force of the resolver rotor 21 with respect to the rotating shaft 5, and absorbs vibration generated in the resolver rotor 21. In this case, as shown in FIG. 4A, a gap S is generated in the positioning recess 33 and the press-fitting portion 5a in the manner in which the resolver rotor 21 is fixed by the press-fitting portions 34 and 35. The resin 40 may be filled.

  In the above embodiment, the resolver rotor 21 is press-fitted and fixed to the press-fitted portions 5a on both sides in the axial direction across the non-press-fitted portion 5b of the rotary shaft 5. However, for example, as shown in FIG. The diameter of the fixed portion of the resolver rotor 21 may be the non-press-fit portion 5b, and the other axial direction may be the press-fit portion 5a. Also in this case, as shown in FIG. 6, the resin 40 may be filled in the gap S between the rotating shaft 5 and the resolver rotor 21 in the non-press-fit portion 5 b or the like.

  Moreover, in the aspect which provides the non-pressing part 5b by making the front end side of the rotating shaft 5 into a reduced diameter, you may mount | wear with the rotating shaft 5, for example, as shown in FIG. 7 (a) (b). The collar member 41 is arranged such that a ring-shaped main body portion 41 a is press-fitted and fixed to the non-press-fit portion 5 b of the rotating shaft 5 and is not press-fitted into the shaft fixing hole 32 of the resolver rotor 21. An engagement piece 41b (engagement portion) is formed to project from the outer peripheral edge of the main body 41a of the collar member 41, and the engagement piece 41b is inserted into the positioning recess 33 of the resolver rotor 21 so as to be closely attached in the circumferential direction. Match. As a result, the collar member 41 does not affect the deformation of the outer detection surface 31 a of the resolver rotor 21, and the idling prevention force of the resolver rotor 21 by the close engagement in the circumferential direction between the engagement piece 41 b and the positioning recess 33. Will improve.

  In the embodiment described above, the fixing structure is applied to the resolver 7 mounted on the brushless motor 1, but the fixing structure may be applied to a resolver mounted on another apparatus.

It is sectional drawing which shows the brushless motor in this embodiment. It is a top view which shows a VR type | mold resolver. For explaining the fixing structure of the resolver rotor, (a) is a plan view, and (b) is a sectional view. (A) is a top view for demonstrating the fixing structure of the resolver rotor in another example, (b) is sectional drawing. It is sectional drawing for demonstrating the fixing structure of the resolver rotor in another example. It is sectional drawing for demonstrating the fixing structure of the resolver rotor in another example. (A) is a top view for demonstrating the fixing structure of the resolver rotor in another example, (b) is sectional drawing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Brushless motor, 5 ... Rotating shaft, 5a ... Press fit part, 5b ... Non press fit part, 7 ... Variable reluctance type (VR type) resolver, 21 ... Resolver rotor, 22 ... Resolver stator, 21x ... Core sheet, 31a ... Outer Detection surface, 32 ... shaft fixing hole, 33 ... positioning recess (positioning part), 40 ... resin, 41 ... collar member, 41b ... engagement piece (engagement part), S ... gap.

Claims (6)

A variable reluctance resolver rotor that is integrated by laminating a plurality of core sheets, has an outer detection surface on the outer side in the radial direction, and a shaft fixing hole that is made non-circular by a positioning portion at the center. And a resolver rotor fixing structure that is press-fitted and fixed to the rotating shaft by the shaft fixing hole,
The fixed portion between the rotating shaft and the resolver rotor is configured with a press-fit portion and a non-press-fit portion arranged side by side in the axial direction, and the resolver at the press-fit portion so that the non-press-fit portion is included in a part of the axial direction. A structure for fixing a resolver rotor, wherein the rotor is press-fitted and fixed to the rotating shaft. In the fixing structure of the resolver rotor according to claim 1,
A structure for fixing a resolver rotor, wherein the rotary shaft is configured with the press-fitted portion and the non-press-fitted portion with a reduced diameter. In the fixing structure of the resolver rotor according to claim 1 or 2,
The resolver rotor fixing structure, wherein the resolver rotor is press-fitted and fixed at the press-fitting portions on both axial sides across the non-press-fitted portion. In the fixing structure of the resolver rotor according to any one of claims 1 to 3,
The resolver rotor fixing structure, wherein the resolver rotor is fixed by filling a resin in a gap between the rotor formed by the non-pressed portion and the rotating shaft. In the fixing structure of the resolver rotor according to claim 1 or 2,
The positioning portion is a positioning recess that opens into the shaft fixing hole, and has an engaging portion that is inserted into the recess and closely engages in the circumferential direction, and is non-press-fit into the shaft fixing hole of the resolver rotor. A resolver rotor fixing structure comprising a collar member that is press-fitted and fixed to the rotating shaft of a portion.   A variable reluctance resolver comprising: a resolver rotor that is press-fitted and fixed to a rotating shaft of a motor using the fixing structure according to any one of claims 1 to 5; and a resolver stator that is disposed on a radially outer side of the resolver rotor. A brushless motor characterized by being mounted.

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