JP5467489B2 - Brushless motor and electric power steering apparatus using the same - Google Patents

Description

  The present invention relates to a brushless motor and an electric power steering apparatus using the same.

  The motor for the electric power steering device assists the steering torque of the driver introduced into the steering system. In this type of motor, brushless motors have been increasingly adopted due to demands for higher output, smaller size, and lower noise. The brushless motor requires a magnetic pole position detection sensor of the rotor. When a resolver is used as the magnetic pole position detection sensor of the rotor, the position of the resolver stator in the rotation direction with respect to the resolver rotor is adjusted with high accuracy. There is a need. For this reason, in consideration of assembly, a resolver is arranged outside the motor case on the output side so that the position of the resolver stator can be adjusted from the outside (see Patent Document 1), and the resolver is housed in the motor case. And the thing of the structure (refer patent document 2) etc. which rotate the resolver stator inside this motor case from the outside is proposed.

Japanese Patent No. 3881351 JP 2006-320189 A

  However, when the resolver is provided on the output side from which the rotating shaft protrudes, for example, the flange on the output side of the motor case becomes large and complicated in shape, and the number of parts increases. Further, in the case of a structure in which the resolver is housed inside the motor case, the resolver stator inside the motor case has to be rotated from the outside, resulting in a complicated structure and an increased number of parts. For this reason, in the case of the former and the latter case, cost increase, assembling property, and deterioration of mounting property are unavoidable. In addition, in the latter case in which the resolver is disposed inside, problems such as the resolver being easily affected by heat from the motor coil occur.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a reduced-sized brushless motor that is low in cost and excellent in assemblability and mountability, and an electric power steering apparatus using the brushless motor. .

To achieve the above object, the present invention provides a brushless motor in which a rotor of a rotating shaft and a stator provided around the rotor are accommodated in a motor case, and one side of the motor case is It is an output side that outputs a rotational force by the rotating shaft, and the rotating shaft penetrates the wall portion on the opposite side of the output side of the motor case, and the rotating shaft protrudes to the outside of the wall portion of the motor case. A projecting portion of the rotating shaft outside the wall of the motor case has a resolver rotor fixed to the rotating shaft and a resolver stator provided around the resolver rotor, and a magnetic pole position of the rotor The sensor is housed in a sensor housing portion formed outside the wall of the motor case, and the sensor housing portion is provided in the resolver stator. A sensor housing main body that is fixed, and the sensor housing main body is configured to be rotatable about the rotation axis with respect to the wall of the motor case, and the sensor housing main body is attached to the motor case. The position in the rotational direction of the resolver stator with respect to the resolver rotor can be adjusted by rotating the sensor rotor main body. A pair of fixed pieces projecting so as to face each other radially outward from the outer periphery, and the cylindrical portion has a smaller diameter than the wall portion of the motor case, and the wall portion of the motor case Is provided with a protruding portion that protrudes outward, and a hole for inserting the protruding portion is formed in the fixed piece of the sensor housing main body, and the hole rotates around the rotation axis. Said convex part in the direction Characterized in that it is formed so as to be movable.

According to the brushless motor having this configuration, since the sensor is provided outside the wall portion on the opposite side to the output side of the motor case, the flange on the output side is enlarged and complicated as in the conventional case, and the number of parts is reduced. There is no increase. Further, since the position of the resolver stator of the sensor can be adjusted outside the motor case, the structure inside the motor case and the harness lead-out portion can be simplified, and the number of parts can be reduced. As a result, the cost of the brushless motor can be reduced, and a brushless motor excellent in assemblability and mountability can be realized.
In addition, the sensor is not easily affected by heat generated in the motor case, and it is not necessary to use a high heat-resistant material. Further, since the sensor is housed in the sensor housing portion, it is possible to prevent intrusion of foreign matter and to realize a highly reliable motor.
Further, since it is not necessary to pass the sensor harness through the motor case, the structure inside the motor case can be simplified in this respect as well. Furthermore, even in a motor case processed by drawing, for example, the sensor housing portion is provided outside the wall portion of the motor case, so that a simple configuration can be achieved.
According to this configuration, the position adjustment of the resolver stator with respect to the resolver rotor can be easily performed with high accuracy.
In this case, the rotation of the sensor housing portion main body with respect to the motor case can be performed with a simple structure.

  The convex part of the wall part of the motor case and the hole part of the sensor housing part main body may be formed on both sides of the rotating shaft. In such a case, the sensor housing portion main body can be rotated 180 degrees around the rotation axis to easily change the direction in which the sensor harness is pulled out, increasing the degree of freedom of wiring and improving the mountability to a vehicle or the like. be able to.

  In the brushless motor, the sensor housing portion main body has a cylindrical portion having one surface opened and the other surface closed, and the sensor housing portion is an opening on the one surface side of the tubular portion. The portion may be formed closed by a wall portion of the motor case.

  A seal member may be interposed in a contact portion between the sensor housing portion main body and the wall portion of the motor case. In this case, for example, waterproofness in the sensor housing portion can be improved.

  A wiring hole through which the wiring of the sensor passes may be formed in the sensor housing portion main body. In this case, the wiring of the sensor is simplified, and for example, the mounting property of a brushless motor on a vehicle or the like can be improved.

  According to another aspect of the present invention, there is provided an electric power steering apparatus that applies a steering assist torque to a vehicle steering system by the brushless motor. In this case, an electric power steering device that is low in cost and excellent in assemblability can be realized.

  According to the present invention, it is possible to realize a miniaturized brushless motor that is low in cost and excellent in assembling and mounting properties.

  Hereinafter, embodiments of a brushless motor and an electric power steering apparatus using the same according to the present invention will be described with reference to FIGS.

  FIG. 1 shows a column-type electric power steering apparatus 10, in which reference numeral 11 denotes a steering shaft, 12 denotes a housing of the steering shaft 11, 20 denotes a rack and pinion type motion conversion mechanism, and 30 denotes a reduction gear box. These constitute a vehicle steering system. Reference numeral 13 denotes a power assist electric motor steering motor (hereinafter referred to as a brushless motor) for applying steering assist torque to the steering system.

  The steering shaft 11 includes a steering input shaft 11a and a steering output shaft 11b, and is supported inside the housing 12 so as to be rotatable about an axis. The housing 12 is fixed to a predetermined position in the vehicle interior in a state where the lower portion is inclined forward. A steering wheel (not shown) is fixed to the upper end of the steering input shaft 11a, and rotates in synchronization with the steering wheel.

  Further, the steering input shaft 11a and the steering output shaft 11b are connected via a torsion bar of the torque sensor 40. The steering torque is transmitted from the steering wheel to the steering output shaft 11b through the steering input shaft 11a. The steering torque is detected by the torque sensor 40, and the output of the brushless motor 13 is controlled based on the detected steering torque.

  The rack-and-pinion type motion conversion mechanism 20 is disposed substantially horizontally in the engine room at the front portion of the vehicle with the longitudinal direction being the left-right direction of the vehicle, and the rack shaft 21 is movable in the axial direction. A pinion shaft 22 having a tooth portion that is supported obliquely and meshes with a tooth portion of the rack shaft 21, and a cylindrical case 23 that supports the rack shaft 21 and the pinion shaft 22 are provided. A front wheel is attached to a knuckle (not shown) provided on both ends of the rack shaft 21 of the rack and pinion type motion conversion mechanism 20.

  The pinion shaft 22 and the lower end of the steering output shaft 11 b are connected by two universal joints 15 and 16 and a connecting member 17. Further, a reduction gear box (gear box) 30 is disposed at an intermediate position in the axial direction of the steering output shaft 11b. A steering assist torque is applied from the brushless motor 13 to the steering output shaft 11b, which is a vehicle steering system, via the reduction gear box 30.

  Next, the brushless motor 13 will be described. As shown in FIG. 2, the brushless motor 13 is, for example, a substantially bottomed cylindrical motor case 50 formed by drawing, and a substantially plate-like shape that is attached so as to close the opening on the front side of the motor case 50. The outer portion is constituted by the flange 51.

  The motor case 50 includes a cylindrical body portion 53 that extends along the motor axis direction, and a bottom portion 54 that faces the flange 51 and serves as a wall portion that closes the rear side of the body portion 53 in the motor axis direction. A flange 51 is connected to the front side of the body portion 53 in the motor axial direction. A seal groove 51a is formed in the circumferential portion in the contact portion between the flange 51 and the body 53, and an O-ring 56 is disposed in the seal groove 51a. The flange 51 and the motor case 50 are sealed by the O-ring 56.

  On the outer surface of the bottom portion 54 of the motor case 50, an annular recess 59 that is recessed annularly is formed inside the motor case 50. Due to the annular recess 59, a circular bearing housing 60 that is recessed outward is formed at the center of the inner surface of the bottom 54. A bearing 61 is held in the bearing housing 60. A through hole 62 penetrating in the motor shaft direction is formed at the center of the bearing housing 60.

  A stator 66 is fixed to the inner peripheral surface of the body portion 53 of the motor case 50, and an insulator 67 is disposed on both sides of the stator 66 in the motor axial direction. A coil 68 is connected to the stator 66 via the insulator 67. It is wound.

  The flange 51 is fitted in the opening on the front side of the body portion 53 of the motor case 50. On the surface of the flange 51 on the motor case 50 side (rear side), a recess 70 is formed that is recessed on the front side opposite to the motor case 50. A bearing holding recess 72 for holding the bearing 71 is formed in the center of the front side surface of the flange 51. The bearing holding recess 72 is held in the rear side. The rotating shaft 76 of the rotor 75 is rotatably supported by the motor case 50 and the flange 51 by the front bearing 71 held in the bearing holding recess 72 and the rear bearing 61 held by the bearing housing 60. . The rotor 75 has a structure in which a magnet is disposed around a rotor core (not shown) and covered with a magnet case.

  The rotating shaft 76 of the rotor 75 protrudes outward from the front flange 51, and the protruding portion is connected to a reduction mechanism (not shown) of the reduction gear box 30 shown in FIG. It has become.

  Note that mounting holes 91 are formed in the flange 51, and the brushless motor 13 is fixed to the reduction gear box 30 by the bolts 92 shown in FIG. That is, the brushless motor 13 is fixed to the reduction gear box 30 at the flange 51 on the output end 77 side of the rotating shaft 76 shown in FIG.

  A terminal block 94 is disposed in the recess 70 of the flange 51. A through hole 98 through which the rotation shaft 76 passes is formed in the center of the terminal block 94. A coil 68 is connected to a terminal 95 provided on the terminal block 94. A power harness 99 for power supply is connected to the terminal block 94, and power is supplied from the power harness 99 to the coil 68 through the terminal block 94.

  The rear end of the rotating shaft 76 of the rotor 75 protrudes outside the motor case 50 from a through hole 62 formed in the bottom 54 of the motor case 50. A resolver rotor 80 is fixed to the rotating shaft 76 of the portion protruding from the through hole 62. A resolver stator 81 is provided around the resolver rotor 80 so as to face each other. The resolver stator 81 detects the rotational position of the magnetic poles of the rotor 75 by detecting the rotational position of the resolver rotor 80, and the sensor 83 detects the magnetic pole position of the rotor 75 by the resolver rotor 80 and the resolver stator 81. Is configured.

  The sensor 83 is accommodated in a sensor housing 100 as a sensor accommodating portion formed outside the bottom portion 54 of the motor case 50. The housing main body 100a forming the sensor housing 100 has a bottomed cylindrical cylindrical portion 101 whose one surface is open and the other surface is closed, and a radial direction from the outer peripheral side of the cylindrical portion 101. And a pair of fixing pieces 102 extending so as to face each other. The sensor housing 100 is formed by closing the opening side of the cylindrical portion 101 with the bottom 54 of the motor case 50. A resolver stator 81 is fixed to the inner peripheral surface of the cylindrical portion 101 of the housing body 100a. In addition, a wiring hole 101 a is formed in the cylindrical portion 101 of the housing main body 100 a, and a communication sensor harness 103 drawn from the wiring hole 101 a is connected to the resolver stator 81.

  The opening edge 101 b of the cylindrical portion 101 is fitted in a circular recess 59 formed in the bottom portion 54 of the motor case 50. Thereby, the housing main body 100a is positioned so that the shaft center coincides with the motor case 50. A seal groove 100b is formed in a circumferential direction at a contact portion between the housing main body 100a and the bottom portion 54 of the motor case 50, and an O-ring 106 as a seal member is disposed in the seal groove 100b. The O-ring 106 seals the inside of the sensor housing 100.

  Further, as shown in FIGS. 2 and 3, the fixing piece 102 of the housing main body 100 a is formed with a positioning hole 102 a as a hole portion composed of an arc-shaped long hole centered on the axis of the rotating shaft 76. . The positioning holes 102a are formed, for example, at two locations facing each other across the axis. As shown in FIG. 2, a bolt hole 54a is formed in the bottom 54 of the motor case 50 at a position corresponding to the positioning hole 102a. Bolts (positioning rods) 104 as projections are fitted into the bolt holes 54 a from the inside of the motor case 50. With the bolt 104 inserted into the positioning hole 102 a, the housing body 100 a is fastened and fixed to the bottom 54 of the motor case 50 by screwing the nut 105 into the bolt 104 from the outside of the fixing piece 102. At this time, in the sensor housing 100, the resolver stator 81 is disposed to face the outside of the resolver rotor 80.

  In the sensor 83, when adjusting the position of the resolver stator 81 in the rotational direction with respect to the resolver rotor 80, the housing body 100 a is rotated around the motor shaft while the nut 105 is loosened. When changing the phase of the sensor harness 103 to the opposite side, the nut 105 is removed, the housing body 100a is removed from the bottom 54 of the motor case 50, and rotated 180 degrees as shown in FIG. The bolt 104 is inserted into the positioning hole 102a, and the nut 105 is screwed and fastened.

  According to the present embodiment described above, since the sensor 83 is provided outside the bottom portion 54 opposite to the output side of the motor case 50, the flange on the output side becomes larger and complicated as in the conventional case. The number of parts does not increase. In addition, since the position of the resolver stator 81 of the sensor 83 can be adjusted outside the motor case 50, the structure inside the motor case 50 and the harness lead-out portion can be simplified, and the number of parts can be reduced. As a result, the cost of the brushless motor 13 can be reduced, and the brushless motor 13 with excellent assemblability and mountability can be realized.

  Further, the sensor 83 is not easily affected by the heat generated in the motor case 50, and it is not necessary to use a highly heat-resistant material. In addition, since the sensor 83 is housed in the sensor housing 100, entry of foreign matter can be prevented, and the highly reliable brushless motor 13 can be realized. Further, since it is not necessary to pass the sensor harness of the sensor 83 through the motor case, the structure inside the motor case 50 can be simplified in this respect as well. Furthermore, even in the motor case 50 processed by drawing, for example, the sensor housing 100 is provided outside the wall portion 54 of the motor case 50, so that a simple configuration can be achieved.

  Further, the housing body 100a is configured to be rotatable about the rotation shaft 76 of the rotor 75 with respect to the motor case 50. By rotating the housing body 100a with respect to the motor case 50, a resolver stator for the resolver rotor 80 is provided. The position adjustment 81 can be easily performed with high accuracy.

  A bolt 104 protruding outward is provided on the wall portion 54 of the motor case 50, and a hole portion 102 a into which the bolt 104 is inserted is formed in the housing main body 100 a, and the hole portion 102 a rotates around the rotation shaft 76. Since the bolt 104 can be moved in the direction, the housing body 100a can be rotated with respect to the motor case 50 with a simple structure.

  The bolts 104 of the wall portion 54 of the motor case 50 and the holes 102a of the housing main body 100a are formed at two positions on both sides of the rotation shaft 76. Therefore, the housing main body 100a is rotated around the rotation shaft 76 by 180 degrees. By attaching, the direction in which the sensor harness 103 is pulled out can be easily changed, the degree of freedom of wiring can be increased, and the mountability to a vehicle or the like can be improved.

  Since the O-ring 106 is interposed at the contact portion between the housing main body 100a and the wall portion 54 of the motor case 50, the waterproofness in the sensor housing 100 can be improved.

  Since the wiring hole 101a through which the sensor harness 103 passes is formed in the housing main body 100a, the wiring of the sensor 83 is simplified, and for example, the mounting property of the brushless motor 13 on a vehicle or the like can be improved.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be made within the scope of the ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, in the above-described embodiment, the bolt 104 is inserted into the positioning hole 102a of the housing main body 100a and the nut 105 is screwed and fixed, but the means for fixing the housing main body 100a to the bottom 54 of the motor case 50 is other For example, a pin (positioning rod) that can be inserted into the positioning hole 102 a may be provided on the bottom 54 of the motor case 50.

1 is a front view showing an overall configuration of an electric power steering apparatus to which an embodiment of a brushless motor according to the present invention is applied. It is sectional drawing which shows the brushless motor of the embodiment. It is a reverse view which shows the brushless motor of the embodiment. It is a reverse view which shows the brushless motor of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 13 Brushless motor 50 Motor case 54 Bottom part 66 Stator 75 Rotor 76 Rotating shaft 80 Resolver rotor 81 Resolver stator 83 Sensor 100 Sensor housing 100a Housing main body

Claims (6)

A brushless motor in which a rotor of a rotating shaft and a stator provided around the rotor are housed in a motor case,
One side of the motor case is an output side that outputs the rotational force of the rotor by the rotary shaft, and the rotary shaft passes through a wall portion on the opposite side of the output side of the motor case, and the rotary shaft is Protrudes to the outside of the motor case wall,
The protruding portion of the rotating shaft outside the wall of the motor case has a resolver rotor fixed to the rotating shaft and a resolver stator provided around the resolver rotor, and detects the magnetic pole position of the rotor. A sensor is provided,
The sensor is housed in a sensor housing portion formed outside the wall portion of the motor case,
The sensor accommodating portion has a sensor accommodating portion main body to which the resolver stator is fixed,
The sensor housing part body is configured to be rotatable around the rotation axis with respect to the wall part of the motor case, and the sensor housing part body is rotated with respect to the motor case, thereby rotating the sensor housing body against the resolver rotor. The position in the rotational direction of the resolver stator is adjustable,
The sensor housing portion main body includes a cylindrical portion whose outer surface is closed, and a pair of fixed pieces that protrude from the outer periphery of the cylindrical portion toward each other in the radial direction,
The cylindrical portion has a smaller diameter than the wall portion of the motor case,
The wall of the motor case is provided with a convex portion protruding outward,
A hole in which the convex portion is inserted is formed in the fixed piece of the sensor housing portion main body,
The hole portion is a brushless motor formed so that the convex portion can move in a rotation direction around the rotation axis.   2. The brushless motor according to claim 1, wherein the convex portion of the wall portion of the motor case and the hole portion of the sensor housing main body are formed on both sides of the rotation shaft. The sensor housing part main body has a cylindrical part having one surface opened and the other surface closed,
3. The brushless motor according to claim 1, wherein the sensor housing portion is formed by closing an opening portion on the one surface side of the cylindrical portion with a wall portion of the motor case. 4. .   The brushless motor according to claim 3, wherein a seal member is interposed in a contact portion between the sensor housing portion main body and the wall portion of the motor case.   The brushless motor according to claim 1, wherein a wiring hole through which the sensor wiring passes is formed in the sensor housing portion main body.   An electric power steering apparatus that applies steering assist torque to a steering system of a vehicle by the brushless motor according to any one of claims 1 to 5.

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