WO2008035754A1

WO2008035754A1 - Brushless motor

Info

Publication number: WO2008035754A1
Application number: PCT/JP2007/068337
Authority: WO
Inventors: Satoshi Shinfuku; Masayuki Okubo
Original assignee: Mitsuba Corporation
Priority date: 2006-09-22
Filing date: 2007-09-21
Publication date: 2008-03-27
Also published as: JP5064401B2; JPWO2008035754A1

Abstract

A resolver stator (33) is contained in a resolver holder (34). The resolver holder (34) includes a cylindrical holder part (61). The resolver stator (33) is coaxially contained in the holder part (61). A holder mounting rib (39) formed coaxially with a bearing fixing part (40) projects from a bracket (24). A bearing (22b) for supporting a rotor shaft (21) is fixed to the bearing fixing part (40). The holder part (61) of the resolver holder (34) is lightly press-fitted to the outer periphery of the holder mounting ribs (39). Thus, the resolver stator (33) can be installed on a rotor shaft (21) with high center accuracy.

Description

Specification

Brushless motor technology

TECHNICAL FIELD [0001] The present invention relates to a brushless motor, and more particularly, to a mounting structure for a rotor position detecting device in a brushless motor.

Background art

In general, in a brushless motor, the rotational position of a rotor is detected, and based on the detected rotor rotational position, a stator-side coil (stator coil) is sequentially excited to rotationally drive the rotor. Conventionally, detection devices using encoders, Hall ICs, etc. have been used to detect the rotational position of the rotor. In recent years, brushless motors using resolvers have also increased. The resolver has a simple structure that is resistant to high temperatures and vibrations and is not easily damaged.

. For this reason, the use of resolvers for in-vehicle motors, especially motors for electric power steering devices (EPS), is increasing.

FIG. 8 is a cross-sectional view showing a configuration of a conventional brushless motor using a resolver. In the brushless motor 100 in FIG. 8 (hereinafter abbreviated as “motor 100”), a resorno 102 is used to detect the rotational position of the rotor 101. The resolver 102 includes a resolver stator 103 and a resolver rotor 104, and an exciting coil 105 is wound around the stator. On the other hand, a resolver rotor 104 formed of a magnetic material is disposed on the rotor side, and the resolver rotor 104 is fixed to the rotor shaft 106 of the motor 100. In such a resolver 102, when a high-frequency signal is applied to the stator-side excitation coil 105, the phase of the signal flowing through the stator-side detection coil (not shown) changes depending on the rotational position of the rotor 101. The rotational position of the rotor 101 is detected by comparing this detection signal with the reference signal.

[0004] On the other hand, there are assembly errors in resolvers and motors, and processing errors also exist in the resolvers themselves. For this reason, the rotor detection position may vary depending on the rotation direction of the motor. Therefore, in a brushless motor using a resolver, it is necessary to adjust the origin of the resolver so that there is no difference between the left and right rotations of the motor. Especially for EPS brushless For motors, fine control based on the rotor rotational position is required to improve steering feeling. Therefore, EPS motors require high accuracy in detecting the rotor rotational position, and origin adjustment is essential.

[0005] In general, the detection signal accuracy of the resolver is indicated by an error between the rotor rotation angle and the resolver detection signal, and the more linear the relationship between the two, the more accurate the sensor. In brushless motors, the higher the rotor position detection accuracy, the more accurate energization is possible, and torque fluctuations can be suppressed and the steering feeling can be improved. Therefore, in the resolver origin adjustment, the induced voltage waveform of the motor and the detection signal of the resolver are compared, and the resolver stator mounting position is finely adjusted in the rotational direction, so that the rise of the resolver signal reaches the determined rotor rotational position. adjust. As a result, it is possible to obtain a brushless motor with little torque fluctuation, in which the rising force S position of the resolver signal corresponds to the rotor rotational position and the rotational left-right difference is eliminated.

[0006] For such origin adjustment, in a brushless motor using a resolver, an origin adjustment function is usually provided on a bracket attached to the end surface of the motor. For example, in the motor 100 of FIG. 8, an adjustment hole is formed in the bracket 108 at the left end of the motor in order to adjust the attachment position of the resolver holder 107 to which the resolver stator 103 is attached. FIG. 9 is a left side view of the motor 100, and the bracket 108 is provided with a resolver adjustment hole 109 and a resolver mounting hole 110. The resolver holder 107 is attached to the motor 108 inward force, and the bracket 108. At this time, the fixed piece 107 a force of the resolver holder 107 is output from the resolver mounting hole 110 to the outside of the bracket 108. After the fixing piece 107a is taken out from the resolver mounting hole 110, the resolver holder 107 is rotated in the circumferential direction, and the fixing screw 111 is temporarily fixed.

In this state, origin adjustment is performed, and the resolver holder 107 is appropriately moved in the circumferential direction. In the motor 100, a long hole through which the fixing screw 111 is passed is formed in the fixing piece 107a. The resolver holder 107 can move in the circumferential direction along the long hole. Therefore, when adjusting the origin, the resolver holder 107 is moved in the circumferential direction by using the long hole and the adjustment hole 109 to adjust the mounting position. After adjusting the origin, tighten the fixing screw 111 to fix the resolver holder 107 to the bracket 108. Note that a sealing cap is attached to the resolver adjusting hole 109 after the motor has been assembled. Next, such a motor 100 is assembled as follows. FIG. 10 is an explanatory diagram showing the assembly configuration of the motor 100. First, the assemblies 112, 113, and 114 are assembled. In this case, the bracket assembly 112 includes a bracket 108, a resolver holder 107 to which a bearing 115 and a resolver stator 103 are attached, and the bracket 115 and the resolver holder 107 are assembled to the bracket 108. A sensor wire 116 is connected to the resolver stator 103. The sensor wire 116 is drawn out in the radial direction from the outer periphery of the bracket assembly 112.

The rotor assembly 113 includes a motor rotor 101 and a resolver rotor 104.

The rotor 101 has a configuration in which a rotor core 117 is fixed to a rotor shaft 106, a magnet holder 118 is attached, a magnet 119 is press-fitted into the magnet holder 118, and a magnet cover 120 is attached to the outside of the magnet 119. ing. The resolver rotor 104 is also fixed to the rotor shaft 106 and is arranged adjacent to the end of the magnet holder 118 of the rotor 101. Further, the stator assembly 114 includes a case 121, a stator core 123 fixed in the case 121 and wound with a motor coil 122, and a bus bar unit 124 attached to the end of the stator core 123. The stator core 123 is press-fitted or adhesively fixed in the case 121 !.

[0010] After each assembly 112, 113, 114 is threaded, the motor 100 first assembles the rotor assembly 113 to the bracket assembly 112 (procedure A in FIG. 10). Next, the assembly of the bracket assembly 112 and the rotor assembly 113 is assembled to the stator assembly 114 (step B in FIG. 10). Thereafter, the lead wire 126 for power supply is fixed to the bus bar unit 124 by welding via the lead wire welding hole 125 provided in the bracket 108. As a result, the motor 100 configured as shown in FIG. 8 is assembled. In the motor 100, the origin adjustment described above is performed after checking the resistance value and insulation state of the motor. After completing various characteristic checks, the brushless motor is completed.

Patent Document 1: Japanese Patent Laid-Open No. 2005-229721

Disclosure of the invention

Problems to be solved by the invention

[0011] However, with conventional brushless motors such as S et al., Fig. 8, the sensing accuracy of the resolver There is a problem that (rotor position detection accuracy) is easily affected by component assembly errors. That is, since the motor 100 in FIG. 8 is configured to screw the resolver holder 107 to the bracket 108, an error occurs in the mounting position of the resolver holder 107 due to play between the screw mounting hole and the fixing screw. there is a possibility. If an error occurs in the mounting position of the resolver holder 107, a misalignment may occur between the resolver stator 103 and the resolver rotor 104 fixed thereto. When such misalignment occurs between the stator and the rotor, there is a problem that the linearity between the rotor rotation angle and the detection signal of the resolver is lost, and the detection signal accuracy of the resolver is lowered. In particular, there is a problem that EPS motors contribute to the deterioration of steering feeling, and countermeasures have been demanded.

An object of the present invention is to prevent misalignment between a resolver stator and a resolver rotor in a brushless motor, and to improve rotor position detection accuracy.

Means for solving the problem

[0013] A brushless motor of the present invention includes a stator including a core around which a drive coil is wound and a case that accommodates the core, a bracket that is attached to one end of the case, and the case and the bracket that are freely rotatable. A rotor having a shaft supported by the shaft and a magnet attached to the shaft and rotatably disposed inside the stator, a resolver rotor attached to the shaft and rotating together with the magnet, and an outer side of the resolver rotor And a resolver stator having a detection coil that changes a phase of an output signal as the resolver rotor rotates, wherein the resolver stator is a cylindrical resolver. The resolver holder is housed in the holder, and the resolver holder is mounted on the bracket. It is mounted on a holder mounting part formed concentrically with the shaft.

[0014] In the present invention, the resolver stator is accommodated in the cylindrical resolver holder, and a holder mounting portion is formed concentrically with the shaft on the bracket, and the resolver holder is mounted on the holder mounting portion. As a result, the resolver stator can be attached to the rotor shaft with high accuracy, and misalignment between the resolver stator and the resolver rotor can be suppressed. For this reason, the linearity between the rotor rotation angle and the detection signal of the resolver is increased, and the rotor position detection accuracy is improved. [0015] In the brushless motor, the resolver holder is provided with a holder portion in which the resolver stator is accommodated concentrically, and the holder portion is fitted to the outer periphery of the holder mounting portion, that is, the holder portion is attached to the holder. It may be attached by fitting to the outer periphery of the attachment portion. Further, the holder part may be fitted to the outer periphery of the holder attaching part in a light press-fit state. Furthermore, the holder mounting portion may be formed so as to protrude along the axial direction at the central portion of the bracket.

[0016] In addition, the resolver holder may be formed of a material having a thermal expansion coefficient approximate to that of the resolver stator, so that the thermal expansion of the resolver stator or the resolver holder may occur between the two. There is no gap, and play due to thermal deformation between the resolver holder and the resolver stator is suppressed, and it is possible to prevent a decrease in the accuracy of the resolver signal.

The invention's effect

[0017] According to the brushless motor of the present invention, the resolver stator is accommodated in the cylindrical resolver holder by the brushless motor having the resolver rotor and the resolver stator, and the resolver holder is attached to the bracket. In addition, the resolver stator can be attached to the rotor shaft with good core accuracy because it is mounted on the holder mounting portion formed concentrically with the shaft. Accordingly, the misalignment between the resolver stator and the resolver rotor can be suppressed, the linearity between the rotor rotation angle and the detection signal of the resolver is increased, and the rotor position detection accuracy can be improved. For this reason, for example, when the brushless motor is used for EPS, the torque fluctuation of the motor is suppressed, and the steering feeling can be improved.

Brief Description of Drawings

FIG. 1 is a cross-sectional view of a brushless motor that is Embodiment 1 of the present invention.

2 is an exploded perspective view of the brushless motor of FIG.

FIG. 3 is a perspective view showing a configuration of a bracket holder unit.

FIG. 4 is an explanatory diagram showing a configuration of a resolver holder.

FIG. 5 is an explanatory view showing an angle error between a rotor rotation angle and a resolver detection signal, and shows a comparison between a conventional brushless motor and a motor according to the present invention.

FIG. 6 is an explanatory view showing the structure of the bracket. FIG. 7 is a cross-sectional view showing a configuration of a brushless motor that is Embodiment 2 of the present invention.

8 is a _c [9] a left side view of the brushless motor of FIG. 8 is a sectional view showing a conventional brushless motor configuration using resolver.

FIG. 10 is an explanatory view showing an assembly configuration of the brushless motor of FIG.

Explanation of symbols

1 Brushless motor 2 Stator

3 Rotor 4 Case

5 Stator core 6 Stator coin

oa coil end 7

8 split core 9 insulator

11 Feeding terminal 21 Rotor shaft

22a, 22b Bearing 23 Fixing screw

24 Bracket 25 Rotor core

26 Magnet 27 Magnet Honoreda

28 Magnet Kanoichi 31 Resonoreno

32 Rotor 33 Stator

33a Terminal 34 Resonor Leba Honoreda

35 Bracket holder unit 35a Holder holder

35b Rib 36 Sensor harness

37 Insulator 38 Rubber grommet

39 Holder mounting rib 40 Bearing fixing part

41 Resolver holder fixing rat 42 Mounting screw

43 External power supply terminal 44 Connection terminal

45 Main unit 46 Busbar terminal

47 Body 48a Welding hole

48b Resolver fixing hole 48c Resolver adjustment hole 54 Rotor

56 cases

58 Bearing fixing part

61 Holder

62

64a- -64c

66 round holes

101 rotor

103 Resonator Leva Stator

105 excitation coil

107 Resonorebaho Noreda

108

110 Mounting hole

112

114 steps

116 Sensor wire

118

120 cases

122 Motor coiler Stator core

124 Nossue-Lead wire weld hole

126 Lead wire

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Example 1

FIG. 1 is a cross-sectional view of a brushless motor that is Embodiment 1 of the present invention, and FIG. 2 is an exploded perspective view of the brushless motor of FIG. As shown in FIG. 1, a brushless motor 1 (hereinafter abbreviated as “motor 1”) is an inner rotor type brushless motor having a stator 2 on the outside and a rotor 3 on the inside. The motor 1 is, for example, a column assist type electric power steerer. It is used as a power source for the driving device (EPS), and provides operational assistance to the steering shaft of the car. The motor 1 is attached to a reduction mechanism (not shown) provided on the steering shaft, and the rotation of the motor 1 is transmitted to the steering shaft by being reduced by the reduction mechanism.

The stator 2 includes a bottomed cylindrical case 4, a stator core 5, a stator coil 6 wound around the stator core 5 (hereinafter abbreviated as coil 6), and a bus bar unit attached to the stator core 5. (Terminal unit) 7 The case 4 is formed in a bottomed cylindrical shape with iron or the like, and a bracket 24 made of aluminum die cast is attached to the opening by a fixing screw 23. The stator core 5 is composed of a plurality of divided cores 8 and nine divided cores 8 are assembled in the circumferential direction. The split core 8 is formed by stacking core pieces made of electromagnetic steel plates, and an insulator 9 made of synthetic resin is attached around the core.

A coil 6 is wound around the outside of the insulator 9. The end portion 6 a of the coil 6 is drawn out in the radial direction at one end side of the stator core 5. A bus bar unit 7 is attached to one end side of the stator core 5. In the bus bar unit 7, a copper bus bar is insert-molded in a synthetic resin main body. Around the bus bar unit 7, a plurality of power supply terminals 11 protrude in the radial direction. When the bus bar unit 7 is attached, the coil end 6 a is welded to the power supply terminal 11. In the bus bar unit 7, the number of bus bars corresponding to the number of phases of the motor 1 (here, three for the U phase, V phase, and W phase) is provided. Each coil 6 is electrically connected to a power supply terminal 11 corresponding to the phase. After the bus bar unit 7 is attached, the stator core 5 is press-fitted into the case 4 and fixedly adhered to the inner peripheral surface of the case.

A rotor 3 is inserted inside the stator 2. The rotor 3 has a rotor shaft 21. The rotor shaft 21 is rotatably supported by bearings 22a and 22b. The bearing 22a is fixed to the center of the bottom of the case 4, and the bearing 22b is fixed to the center of the bracket 24. A cylindrical rotor core 25 is fixed to the rotor shaft 21. A segment type magnet (permanent magnet) 26 is attached to the outer periphery of the rotor core 25. A magnet holder 27 made of synthetic resin is attached to the rotor shaft 21. It has been deceived. The magnet 26 is disposed on the outer periphery of the rotor core 25 so as to be held by the magnet holder 27. In the motor 1, six magnets 26 are arranged along the circumferential direction. A magnet cover 28 having a bottomed cylindrical shape is attached to the outside of the magnet 26.

A rotor (resolver rotor) 32 of a resolver 31 that is a rotation angle detection means is attached to the end of the magnet holder 27. On the other hand, the stator (resolver stator) 33 of the resolver 31 is press-fitted into a metal resolver holder 34 and is fixed to the bracket holder unit 35 in this state. FIG. 3 is a perspective view showing the configuration of the bracket holder unit 35. As shown in FIG. 3, at the center of the bracket holder unit 35, a holder accommodating portion 35a into which the resolver holder 34 is inserted is provided. A plurality of ribs 35b project from the inner wall of the holder accommodating portion 35a. Here, eight ribs 35b are equally provided in the circumferential direction, and project slightly less than lmm inward in the radial direction. The resolver holder 34 is attached in the holder accommodating portion 35a so as to be lightly press-fitted inside the rib 35b, and is temporarily held in the bracket holder unit 35.

A sensor harness 36 is fixed to the resolver stator 33. A signal output as the rotor 32 rotates is transmitted to a controller or the like (not shown) via the sensor harness 36. The sensor harness 36 is welded to the terminal portion 33a of the stator 33. A synthetic resin insulator 37 is attached to the terminal portion 33a. The sensor harness 36 is routed between the bracket 24 and the bracket holder unit 35 along the circumferential direction. Then, it is pulled out from the outer periphery of the bracket 24 through the rubber grommet 38 to the outside of the apparatus.

In the motor 1, the resolver holder 34 is formed in a bottomed cylindrical shape, and is fitted into the central portion of the bracket holder unit 35. FIG. 4 is an explanatory diagram showing the configuration of the resolver holder 34. As shown in FIG. 4, the resolver holder 34 includes a cylindrical holder part 61, a flange part 62 formed on one end side of the holder part 61, and a through hole formed in the center on the other end side of the holder part 61. The bottom wall 63 is formed. In the holder part 61, the resolver stator 33 is accommodated concentrically. The terminal portion 33a of the stator 33 is disposed in the cutout portion 61a formed in the holder portion 61. In this case, resolver stator 33 and resolver The holders 34 are formed of materials (preferably! /, Equal! /,) That are close to each other in thermal expansion coefficient (preferably within a difference of 10%, particularly preferably within 5%). Therefore, no gap is generated between the resolver holder 34 and the resolver stator 33 even if each member expands due to heat. For this reason, rattling due to thermal deformation between the resolver holder 34 and the resolver stator 33 is suppressed, and a decrease in the accuracy of the resolver signal is suppressed.

[0028] The flange portion 62 protrudes in the radial direction on one end side of the holder portion 61. The flange portion 62 is further provided with protruding pieces 64a to 64c extending in the radial direction. The projecting pieces 64a and 64b are formed at positions facing 1 80 °. A long hole 65 is formed in each projecting piece 64a, 64b. The long hole 65 is formed long in the circumferential direction and is used for fixing the resolver holder 34 and adjusting the origin of the resonance lever 31. A round hole 66 is formed in the projecting piece 64c, and the round hole 66 is exclusively used for adjusting the origin. At the time of origin adjustment, an adjustment jig is inserted into the round hole 66 from the outside of the bracket 24, and the position of the resolver holder 34 is appropriately adjusted in the circumferential direction.

[0029] The open end portion (flange portion 62 side) of the resolver holder 34 is fitted to the outer periphery of the end portion of a holder mounting rib (holder mounting portion) 39 provided on the bracket 24. The holder mounting rib 39 protrudes from the central portion of the bracket 24 in a partially cylindrical shape (cylindrical shape having a notch in a part) in the axial direction. The outer diameter of the holder mounting rib 39 is slightly smaller than the inner diameter of the open end of the resolver holder 34. Therefore, the resolver holder 34 is mounted so as to be lightly press-fitted into the holder mounting rib 39.

On the other hand, a bearing fixing portion 40 is provided inside the holder mounting rib 39. A bearing 22 b that supports the rotor shaft 21 is fixed to the bearing fixing portion 40. The holder mounting rib 39 is formed concentrically with the bearing fixing portion 40. Therefore, when the resolver holder 34 is lightly press-fitted into the holder mounting rib 39, the resolver holder 34 is attached concentrically with the bearing fixing portion 40. As a result, the resolver stator 33 in the holder 61 is attached to the bracket 24 concentrically with the bearing 22b, that is, concentrically with the rotor shaft 21, and the resolver stator 33 is attached to the rotor shaft 21 with high core accuracy. Installed in 1.

[0031] As described above, when a misalignment occurs between the stator 33 and the rotor 32 of the resolver 31, the rotor position detection accuracy is lowered, and in EPS, the steering feeling is lowered. In contrast, Since the motor 1 employs a seal fitting structure in which the resolver holder 34 is lightly press-fitted into the holder mounting rib 39 of the bracket 24, the resolver stator 33 is attached to the rotor shaft 21 concentrically with high core accuracy. For this reason, misalignment between the stator 33 and the rotor 32 in the resolver 31 can be suppressed, the linearity between the rotor rotation angle and the detection signal of the resolver 31 is increased, and the rotor position detection accuracy is improved. It becomes possible to plan. Further, since the resolver holder 34 and the resolver stator 33 are formed of materials having approximate thermal expansion coefficients, rattling due to thermal deformation is suppressed, and in this respect also, the rotor position detection accuracy is improved.

[0032] FIG. 5 is an explanatory diagram showing an angle error between the rotor rotation angle and the resolver detection signal, and shows a comparison between a conventional brushless motor (FIG. 8) and a motor according to the present invention. As is clear from FIG. 5, according to the experiments by the inventors, the conventional motor shown by the alternate long and short dash line has an angular error width of about 5 °, whereas the motor 1 according to the invention shown by the solid line 1 In, the angular error width could be kept within about 1.5 °. In other words, it has become clear that the motor 1 can detect the rotational position of the rotor 3 with three times higher accuracy than a conventional brushless motor. For this reason, the motor 1 can be driven with reduced torque fluctuation, and the steering feeling in EPS can be improved.

[0033] The bracket holder unit 35 is formed of a synthetic resin. In the bracket holder unit 35, a metal resolver holder fixing nut 41 is insert-molded. Two resolver holder fixing nuts 41 are provided corresponding to the long holes 65 of the resolver holder 34. On the other hand, the bracket 24 is formed with a resolver fixing hole 48b for fixing the resolver and a resolver adjusting hole 48c for adjusting the origin of the resolver 31, as shown in FIG. The resolver fixing hole 48b is disposed so as to face the long hole 65 and the resolver holder fixing nut 41, and is formed in a round hole through which the mounting screw 42 can pass.

On the other hand, the resolver adjusting hole 48c is arranged facing the round hole 66. The resolver adjusting hole 48c is formed as a long hole extending in the circumferential direction so that the position of the resolver holder 34 can be adjusted in the circumferential direction. An adjustment jig is inserted into the round hole 66 through the resolver adjustment hole 48c, and the position of the resolver holder 34 is adjusted (origin adjustment). After adjusting the holder position, the resolver holder fixing nut 41 is connected to the outside of the motor 1 through the resolver fixing hole 48b. Mounting screw 42 is screwed in from the part. As a result, the resolver holder 34 is fixed while being sandwiched between the bracket 24 and the bracket holder unit 35.

In the conventional motor 100 (FIG. 8), a resolver adjustment hole 109 and a resolver mounting hole 110 extending in the circumferential direction are provided in the bracket 108. For this reason, the rigidity of the bracket 108, particularly the rigidity around the bearing 115 fixed at the center of the bracket, is lowered, and there is a possibility that the strength is insufficient. In addition, as the rigidity around the bearing is reduced, vibration is applied to the resolver stator 103, which may reduce the sensing accuracy. On the other hand, in the motor 1 of FIG. 1, the bracket holder unit 35 is provided inside the bracket 24, and the resolver holder 34 is attached to the bracket holder unit 35, so that the resolver fixing hole needs to be a long hole. There is no.

That is, as can be seen from FIG. 6, in the motor 1, the hole related to the resolver 31 is a mounting screw.

Only a small resolver fixing hole 48b (round hole) for 42 and a resolver adjusting hole 48c of about 10mm in length are sufficient. Therefore, as is clear from comparison with FIG. 9, the through hole of the bracket 24 can be made smaller than the conventional motor, and the rigidity of the bracket 24 is improved correspondingly, and the strength thereof is also increased. Therefore, a decrease in sensing accuracy due to vibration can be suppressed, and rotor position detection accuracy can be improved.

[0037] The bracket holder unit 35 is also provided with three external power feeding terminals 43. The external power feeding terminal 43 is provided for each of U, V, and W phases. These external power feeding terminals 43 are provided so as to protrude in the radial direction from the side surface of the bracket 24 when the bracket holder unit 35 is assembled to the bracket 24. Each external power feeding terminal 43 (43U, 43V, 43W) is electrically connected to a connection terminal 44 (44U, 44V, 44W) provided in the bracket holder unit 35. Each connection terminal 44 protrudes from the main body 45 of the bracket holder unit 35 in the axial direction, and is welded to the bus bar terminal 46 (46U, 46V, 46W) provided in the bus bar unit 7.

[0038] The bus bar terminal 46 also projects from the main body 47 of the bus bar unit 7 in the axial direction. Therefore, when the motor 1 is assembled, the bus bar terminal 46 and the connection terminal 44 face each other in parallel. In the motor 1, after the bracket 24 is attached to the case 4, the bus bar terminal 46 and the connection terminal 44 are fixed by welding. As shown in Figure 6, the bracket 24 is welded for that purpose. A working hole 48a is formed. A bracket cap 49 is attached to the welding work hole 48a after the welding process.

[0039] Such a motor 1 is assembled as follows. First, the bracket assembly 51, the stator assembly 53, and the rotor assembly 54 are assembled individually. In this case, the bracket assembly 51 is an assembly product in which the bracket 24 in which the bearing 22b is incorporated and the bracket holder unit 35 in which components related to the resolver stator 33 are assembled are integrated and fixed with the tapping pin screw 52. A resolver holder 34 is temporarily held in the bracket holder unit 35 so as to be lightly press-fitted inside the rib 35b. However, the resolver holder 34 itself is not fixed to the bracket 24 at this point (before the origin adjustment), and the position can be shifted in the circumferential direction during the origin adjustment.

[0040] The stator assembly 53 is an assembly product in which the bus bar unit 7 is attached to the stator core 5 around which the coil 6 is wound, and the power supply terminal 11 and the coil end portion 6a are welded and accommodated in the case 4. Configure 2 The rotor assembly 54 is an assembly in which the rotor core 25 is fixed to the rotor shaft 21 and the magnet holder 27 is attached. Then, the magnet 26 is press-fitted and the magnet cover 28 is attached, and the resolver rotor 32 is press-fitted and fixed to the magnet holder 27. The rotor 3 is configured.

[0041] After assembling such assemblies, the rotor assembly 54 is attached to the bracket assembly 51, the stator assembly 53 is externally mounted on the assembly, and the case 4 and the bracket 24 are fastened to the fixing screw 23. Next, the bus bar terminal 46 and the connection terminal 44 are fixed by welding through the welding work hole 48a. In this state, check the motor resistance and insulation state, and then adjust the origin of resolver 31. As described above, the resolver adjustment hole 48c is formed in the bracket 24, and the origin adjustment is performed from the resolver adjustment hole 48c. At that time, an adjusting jig (not shown) is inserted into the resolver adjusting hole 48c, the position of the resonator lever holder 34 is finely adjusted in the circumferential direction using the long hole 65, and the origin of the resolver 31 is adjusted.

[0042] After adjusting the origin, insert the mounting screw 42 from the outside of the bracket 24 and screw it into the resolver holder fixing nut 41 to fix it. As a result, the flange portion 62 of the resolver holder 34 is fixed so as to be sandwiched between the bracket 24 and the bracket holder unit 35. Mounting screw 4 After tightening 2, attach the bracket cap 49. This completes the assembly work of the motor 1, and after that, various characteristic checks, etc. are performed and the product is completed.

[0043] In the motor 1 in FIG. 8, the sensor wire 116 is drawn from the bracket assembly 112 and the lead wire 126 is drawn separately from the stator assembly 114, so that the sensor wire 116 and the lead wire 126 are obstructive. As a result, the assembly work may be difficult to perform. On the other hand, in the motor 1, since the bracket holder unit 35 is integrated with the sensor harness 36 and the power supply lead wire, each wire can be easily handled and assembled easily. In addition, the sensor harness 36 and the lead wire for power feeding are fixed by being sandwiched between the stator assembly 53 and the bracket assembly 51. It has been made easier.

Example 2

Next, a brushless motor that is Embodiment 2 of the present invention will be described. The brushless motor 55 of the second embodiment (hereinafter abbreviated as the motor 55) has a configuration in which the position of the resolver 31 is arranged outside the motor, and the other configuration is almost the same as the motor 1 of the first embodiment. . The same members and parts as those in Example 1 are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 7 is a cross-sectional view showing the configuration of the motor 55. In the motor 55, both ends of the case 56 are open, and aluminum die-cast brackets 57a and 57b are attached to the both sides. In the center of the bracket 57a, a bearing fixing portion 58 to which the bearing 22a is fixed is provided in a cylindrical shape. On the other hand, on the outside of the bracket 57a, a cylindrical holder mounting portion 59 is projected. The holder mounting portion 59 is formed concentrically with the bearing fixing portion 58. A resolver holder 34 to which a resolver stator 33 is fixed is attached to the holder attaching portion 59. The outer diameter of the holder mounting portion 59 is slightly smaller than the inner diameter of the open end of the resolver holder 34. Therefore, the resolver holder 34 is mounted so as to be press-fitted into the holder mounting portion 59.

As described above, the holder mounting portion 59 is provided concentrically with the bearing fixing portion 58. Accordingly, the resolver holder 34 is mounted concentrically with the rotor shaft 21 by lightly press-fitting the resolver holder 34 into the holder mounting portion 59. Thus, even in the motor 55 Since the resolver holder 34 is lightly press-fitted into the holder mounting portion 59, a seal fitting structure is employed, so that the resolver stator 33 is concentrically attached to the rotor shaft 21 with high core accuracy. For this reason, it is possible to suppress the misalignment between the stator 33 and the rotor 32 in the resolver 31, and the linearity between the rotor rotation angle and the detection signal of the resolver 31 is increased, thereby improving the rotor position detection accuracy. It is done.

[0047] Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the above-described first embodiment, a cylindrical boss shape may be used in the same manner as the holder mounting portion 59 of the 1S embodiment 2 in which the holder mounting rib 39 has a partially cylindrical shape. In the resolver holder 34, the end portion of the holder portion 61 is configured to be fitted to the holder mounting rib 39, but the portion to be fitted to the holder mounting rib 39 is not limited to the holder portion 61. For example, a portion having a diameter larger than that of the holder portion 61 may be formed at the end portion of the holder portion 61, and this may be fitted to the holder mounting rib 39. That is, if the resolver holder 34 is mounted on the holder mounting rib 39 so that the resolver stator 33 is arranged concentrically with the rotor shaft 21, any part is mounted on the holder mounting rib 39. Also good.

In addition, in the above-described embodiment, the present invention can be applied to a force S indicating a brushless motor used for column-assisted EPS and other types of EPS motors. In addition, the present invention can be widely applied to general brushless motors as well as motors for EPS and various in-vehicle electric products.

Claims

The scope of the claims

[1] A stator including a core around which a drive coil is wound, a case for housing the core, a bracket attached to one end side of the case,

A rotor including a shaft rotatably supported by the case and the bracket; and a magnet attached to the shaft and rotatably disposed inside the stator; and attached to the shaft and rotated together with the magnet. A brushless motor comprising: a resolver rotor; and a resolver stator that is disposed outside the resolver rotor and includes a detection coil that changes a phase of an output signal as the resolver rotor rotates.

The resolver stator is housed in a resolver holder formed in a cylindrical shape, and the resolver holder is attached to a holder mounting portion formed concentrically with the shaft on the bracket.

[2] The brushless motor according to claim 1, wherein the resolver holder has a holder portion in which the resolver stator is accommodated concentrically, and the holder portion is fitted on an outer periphery of the holder mounting portion. Features a brushless motor.

3. The brushless motor according to claim 1, wherein the holder portion is fitted into the outer periphery of the holder mounting portion in a light press-fit state.

[4] The brushless motor according to claim 1, wherein the holder mounting portion projects from the center portion of the bracket along the axial direction.

5. The brushless motor according to claim 1, wherein the resolver holder is formed of a material having a thermal expansion coefficient approximate to that of the resolver stator.