JP2003299294A - Attachment structure for brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of components in a brushless motor attachment structure, thereby reducing the assembly man-hours and improving the ease of assembly. <P>SOLUTION: The attachment structure of the brushless motor 43 transmits motor output to a reduction gear 45 by attaching a motor case 71 to a reduction gear case 61. One end 76a of a motor axis 76 is supported by a lid 72 via bearings 86. The lid 72 is fitted on the motor case 71. The lid 72 is sandwiched by a recess 71d provided on the motor case 71 and a pressing surface 61d provided on the reduction gear case 71. The lid 72 was suppressed from shifting in the direction of the motor axis 76. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor mounting structure. [0002] A brushless motor is also called a non-commutator motor, and is a motor in which a mechanical contact portion such as a commutator or a brush is removed from the motor and these are electrically replaced. As such a brushless motor, for example, FIG.
Is known. FIG. 5 is a sectional view of a conventional brushless motor mounting structure, and shows that the motor output of the brushless motor 200 is transmitted to a speed reducer 240 via a torque limiter 230. The brushless motor 200
Motor case 201 and opening 2 of motor case 201
01a, a cylindrical outer stator 203 fitted in the motor case 201, and a plurality of armatures 204... Provided on the outer stator 203. , An inner rotor 205 disposed inside the outer stator 203, a motor shaft 206 integrated with the inner rotor 205, and a phase detection sensor 207 for detecting the phase of the inner rotor 205. The plurality of armatures 204 are composed of windings 211 wound around a plurality of bobbins (not shown). The inner rotor 205 is provided with a plurality of permanent magnets 213..., And these permanent magnets 213. In such a brushless motor 200, one end of a motor shaft 206 is supported by a lid 202 via a first bearing 215, and the other end of the motor shaft 206 is supported by a second bearing 2.
16 and is supported by the motor case 201. The lid 20 is inserted into the opening 201a of the motor case 201.
2 and the step 2 provided on the motor case 201.
By contacting the inner end surface of the lid 202 with the lid 201b and holding the lid 202 between the step 201b and the retaining ring 217, the lid 20 in the direction of the motor shaft 206 (the left-right direction in the drawing) is obtained.
2 can be suppressed. The reduction gear 240 includes an input shaft 241 connected to the motor shaft 206 via a torque limiter 230, a worm 242 formed on the input shaft 241, and a worm 242.
243, an output shaft 244 connected to the wheel 243, and a speed reducer case 245 for housing these members. Flange 24 of reduction gear case 245
The flange 201c of the motor case 201 can be attached to 5a by bolting. [0006] However, in the above-mentioned conventional technique, the lid 202 is fitted to the motor case 201, the inner end face of the lid 202 is brought into contact with the step 201b, and then the retaining ring 217 is attached to the motor case 201. By stopping, the lid 202 is formed by the step 201b and the retaining ring 217.
, The movement of the lid 202 in the direction of the motor shaft 206 is suppressed, and thereafter, the motor case 201 is bolted to the reduction gear case 245. Therefore, since a retaining ring 217 for stopping the lid 202 is necessary,
The number of parts is large and the number of assembling steps is increased, and the assembling property is poor. SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique for mounting a brushless motor in which the number of parts can be further reduced, the number of assembling steps can be reduced, and the assembling property can be improved. In order to achieve the above object, a first aspect of the present invention is a brushless motor mounting structure for transmitting a motor output to a speed reducer by mounting a motor case on the speed reducer case. One end of the motor shaft is supported by a lid via a bearing, and this lid is fitted into the motor case, and the lid is sandwiched between a step provided on the motor case and a pressing surface provided on the speed reducer case, thereby obtaining the motor shaft. The feature is that movement of the lid in the direction is suppressed. The lid, which supports one end of the motor shaft via a bearing, is fitted into the motor case and is held between the step provided on the motor case and the pressing surface provided on the reduction gear case. Just by attaching the motor case to the case, the lid can be sandwiched between the step and the pressing surface, and the movement of the lid in the motor axis direction can be suppressed. Therefore, it is not necessary to provide a special part for stopping the lid. As a result, the number of parts of the brushless motor can be further reduced, the number of assembling steps can be reduced, and the assembling property can be improved. Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, a mounting structure of a brushless motor is applied to an electric power steering device for a vehicle. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a schematic diagram of an electric power steering apparatus according to the present invention. Electric power steering device 1
0 is the steering wheel 2 from the steering wheel 11 of the vehicle.
The steering system 22 extending from 1 to 21 includes a steering mechanism 23 and an auxiliary torque mechanism 24 for applying an auxiliary torque to the steering mechanism 23. The steering mechanism 23 includes a steering wheel 1
1 is a steering shaft 12 and a universal joint 13, 13.
3, the pinion shaft 32 of the rack and pinion mechanism 31 is connected to the rack shaft 34 of the rack and pinion mechanism 31 via left and right ball joints 36, 36 and left and right tie rods 37, 37. 2
1 is connected. Rack and pinion mechanism 3
1 includes a pinion 33 formed on a pinion shaft 32 and a rack 35 formed on a rack shaft 34. The driver can steer the steering wheel 11 and steer the left and right steering wheels 21 and 21 via the rack and pinion mechanism 31 and the left and right tie rods 37 and 37 by the steering torque. The auxiliary torque mechanism 24 detects a steering torque of the steering system 22 applied to the steering handle 11 with a steering torque sensor 41, and generates a control signal in a control section 42 based on the detected signal. An auxiliary torque corresponding to the steering torque is generated by the electric motor 43, and the auxiliary torque is generated by the torque limiter 44 and the speed reducer 45.
Is transmitted to the pinion shaft 32 through the shaft. To summarize the above, the electric power steering apparatus 10 uses the steering torque applied to the steering handle 11 to rotate the pinion shaft 3 of the rack and pinion mechanism 31.
2 and the auxiliary torque generated by the electric motor 43 in accordance with the steering torque is transmitted to the pinion shaft 32 via the speed reducer 45, and the rack and pinion mechanism 31 steers the steered wheels 21 and 21. Things. Therefore, the combined torque obtained by adding the assist torque of the electric motor 43 to the steering torque of the driver causes the steering wheels 21,
21 can be steered. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and shows a combined structure of the electric motor 43, the torque limiter 44, and the speed reducer 45. The torque limiter 44 is configured to fit a male tapered inner member 51 serrated to a motor shaft 76 of the electric motor 43 to a female tapered (cup-shaped) outer member 52 serrated to a worm shaft 62 described later. It is a restriction mechanism. Inner member 5
The inner peripheral surface of the outer member 52 can be connected to the outer peripheral surface of the first member 1 with a predetermined frictional force. 53 is a disc spring, and 54 is a nut. The speed reducer 45 is a torque transmitting means for transmitting the auxiliary torque generated by the electric motor 43 to the pinion shaft 32, and comprises a worm gear mechanism housed in a speed reducer case 61. Specifically, the speed reducer 45 is
A worm shaft (input shaft) 62 connected to the motor shaft 76 of the worm shaft via a torque limiter 44, a worm 63 formed on the worm shaft 62, and a worm wheel connected to a pinion shaft (output shaft) 32 that is long in the front and back directions in the figure. 64. The worm shaft 62 is arranged concentrically with the motor shaft 76, and is rotatably supported by the reduction gear case 61 via two bearings 65, 65 and restricts movement in the longitudinal direction of the shaft. Axis. 66 is a leaf spring and 67 is an adjustment bolt. The reduction gear case 61 has an opening 61a which is open toward the motor shaft 76, and the flange 61b and the motor shaft 76 around the opening 61a are larger than the flange 61b.
It is a member formed integrally with a fitting cylindrical portion 61c extending to the side. The motor case 71 forms an opening 71 a opened on the flange 61 b side of the reduction gear case 61, and the opening 71 a
This is a bottomed cylindrical case in which a flange 71b is integrally formed around 1a. The fitting center of the motor case 71 with respect to the speed reducer case 61 can be accurately determined by fitting the fitting cylindrical portion 61c into the opening 71a. Further, by fixing the flanges 61b and 71b to each other with bolts 91,
The motor case 71 can be detachably attached to the speed reducer case 61. The mounting structure of the electric motor 43 is such that the motor case 71 is mounted on the speed reducer case 61.
The motor output is transmitted to the speed reducer 45. 92 is a motor drive control unit. FIG. 3 is a cross-sectional view of the electric motor according to the present invention, and shows the electric motor 43 corresponding to FIG. The electric motor 43 includes the motor case 71, a lid 72 for closing an opening 71 a of the motor case 71, a cylindrical first outer stator 73 fitted in the motor case 71,
A cylindrical second outer stator 74 fitted into the first outer stator 73; a cylindrical inner rotor 75 disposed inside the second outer stator 74; and a motor shaft 76 (output shaft 76) integrated with the inner rotor 75 And the inner rotor 75
And an inner rotor type DC brushless motor including a phase detection sensor 77 for detecting the phase of the motor. Hereinafter, the electric motor 43 will be appropriately referred to as “brushless motor 43” according to the description. The combination structure of the first outer stator 73 and the second outer stator 74 forms a set of outer stators 78 fixed to the motor case 71. Outer stator 78
Are provided with a plurality of armatures 81... Arranged in the circumferential direction. A plurality of armatures 81 ...
Consists of a plurality of bobbins 82 and windings 83 wound around each bobbin 82. The inner rotor 75 has a plurality of permanent magnets 84... Arranged in the circumferential direction, and these permanent magnets 84... Are covered with a thin cylindrical nonmagnetic cover 85. The motor shaft 76 is a horizontal rotation shaft having one end on the output side extending into the reduction gear case 61. The phase detection sensor 77 includes a laminated core rotor 77a attached to the motor shaft 76, and a detection element 77b that magnetically detects the phase of the core rotor 77a. The electric motor 43 (brushless motor 43) has one end 7 on the output side of the motor shaft 76.
6 a is rotatably supported by a lid 72 via a first bearing 86, and the lid 72 is attached to the opening 7 of the motor case 71.
1a and the other end 76b of the motor shaft 76 on the opposite side to the output side via the second bearing 87.
1, characterized in that it is rotatably supported. The first and second bearings 86 and 87 are rolling bearings such as ball bearings. More specifically, the motor case 7
1 has a step 71d formed at a boundary between a relatively large-diameter opening 71a and a small-diameter space 71c deeper than the opening 71a. The inner end face 7 of the disc-shaped lid 72 is
2a was applied. On the other hand, the speed reducer case 61 has a flat pressing surface 61d formed at the tip of the fitting cylindrical portion 61c. The pressing surface 61 d is connected to the outer end surface 72 of the lid 72.
b. Step 7 provided in motor case 71
By holding the lid 72 between 1d and the pressing surface 61d provided on the reduction gear case 61, the movement of the lid 72 in the direction of the motor shaft 76 (the left-right direction in the drawing) can be suppressed. The lid 72 supports the outer ring of the first bearing 86 while restricting movement to the second bearing 87 side. The motor case 71 supports the outer ring of the second bearing 87 while restricting movement to the first bearing 86 side. The first and second bearings 86 and 87 supported in this manner can support the motor shaft 76 while restricting movement in the axial direction (the left-right direction in the drawing). Further, the first bearing 86 and the second bearing 8
7, a disc spring 88 is interposed between the step of the motor shaft 76 and the inner ring of the second bearing 87. FIG. 4 is an exploded view and an action diagram of a mounting structure of an electric motor (brushless motor) according to the present invention. The procedure for assembling the brushless motor 43 having the above configuration and the procedure for attaching the brushless motor 43 to the speed reducer 45 are as follows. Note that these procedures are described for understanding the mounting structure of the brushless motor 43, and are not limited to these procedures. First, the first bearing 86 is mounted on the lid 72. Next, the second bearing 87 is attached to the motor case 71. Next, the outer stator 78 is attached to the motor case 71. Next, the disc spring 88 is set on the motor shaft 76. Next, the motor shaft 76 is inserted into the motor case 71 and fitted to the second bearing 87. Next, while the first bearing 86 is fitted to the motor shaft 76, the opening 7 of the motor case 71 is
The lid 72 is fitted to 1a. Then, the inner end face 72a of the lid 72 is applied to the step 71d. Next, the motor case 7
The fitting cylinder 61c is fitted into the first opening 71a. Then, the pressing surface 61d is applied to the outer end surface 72b of the lid 72. Finally, the flanges 61b and 71b are overlapped with each other and fixed with bolts 91, and the operation is completed. As a result, step 71d
And the pressing surface 61d sandwiching the lid 72,
The movement of the lid 72 in the direction of the motor shaft 76 (the left-right direction in the drawing) can be suppressed. As is clear from the above description, the lid 72 supporting the one end 76a of the motor shaft 76 via the first bearing 86 is fitted into the motor case 71, and
1d and the pressing surface 61d, so that only the motor case 71 is attached to the speed reducer case 61,
The lid 72 is sandwiched between the step 71d and the pressing surface 61d, so that the movement of the lid 72 in the direction of the motor shaft 76 can be suppressed. Therefore, it is not necessary to provide a special component (retaining ring, bolt, etc.) for stopping the lid 72. In the above embodiment of the present invention,
The mounting structure of the brushless motor 43 is not limited to the configuration applied to the electric power steering device 10. The presence or absence of the torque limiter 44 is optional. For example, the motor shaft 76 and the worm shaft 62 may be connected by a coupling, or the motor shaft 76 may also serve as the worm shaft 62. According to the present invention, the following effects can be obtained by the above-mentioned structure. According to the first aspect of the present invention, the lid supporting one end of the motor shaft via the bearing is fitted into the motor case, and is held between the step provided on the motor case and the pressing surface provided on the reduction gear case. Simply by attaching the motor case to the reduction gear case, the lid can be sandwiched between the step and the pressing surface, and the movement of the lid in the motor axis direction can be suppressed. Therefore, it is not necessary to provide a special part for stopping the lid. As a result, the number of parts of the brushless motor can be further reduced, the number of assembling steps can be reduced, and the assembling property can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of an electric power steering apparatus according to the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. FIG. 3 is a cross-sectional view of an electric motor according to the present invention. 4) Electric motor (brushless motor) according to the present invention
FIG. 5 is an exploded view and action diagram of the mounting structure of FIG. 5 FIG. 5 is a cross-sectional view of the mounting structure of a conventional brushless motor [Explanation of reference numerals] 10: Electric power steering device, 43: Brushless motor (electric motor), 45: Reduction gear, 61 ... reduction gear case, 61b ... flange, 61d ... pressing surface, 71 ... motor case, 71b ... flange, 71d ... step, 72 ... lid, 76 ... motor shaft, 76a ... one end, 86 ... bearing (first bearing).

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takashi Kuribayashi             1-4-1 Chuo, Wako-shi, Saitama Stock Association             Inside the Honda Research Laboratory F term (reference) 5H019 AA09 AA10 BB01 BB05 CC03                       FF01 FF03                 5H605 AA07 AA08 BB10 CC03 CC08                       DD03 DD05 DD09 EA05 EB02                       EB10 EB17                 5H607 BB01 BB05 BB09 BB14 BB26                       CC03 CC09 DD03 DD07 DD08                       DD16 EE21 EE31 EE36 EE54                       FF01 GG02 GG08 HH01 HH09

Claims (1)

1. A brushless motor mounting structure for transmitting a motor output to a speed reducer by mounting a motor case on the speed reducer case, wherein one end of the motor shaft is supported by a lid via a bearing. By fitting the lid into the motor case and holding the lid between a step provided on the motor case and a pressing surface provided on the reduction gear case, the movement of the lid in the motor axial direction was suppressed. Characteristic brushless motor mounting structure.