JP2001275304A - Coreless motor for electrically operated power steering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong service life of a coreless motor for an electrically operated power steering and make heat generation preventable in a commutator and a brush by circulating air through a through hole in a motor housing as a result. SOLUTION: A through-hole 47 which is almost parallel to an axle 19 is opened in a hold disc 43, and a through-hole 49 from the center of the axle 19 and almost parallel to a radial shaft A is opened in a cylinder unit 46 so as to circulate air in a motor housing 35 though these through-holes 47, 49.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coreless motor for electric power steering.

[0002]

2. Description of the Related Art As a coreless motor for electric power steering, for example, Japanese Utility Model Publication No. 3-52606 discloses "Electric booster". According to the above-mentioned technology, according to the figures in the publication, a worm 6 (ball screw) is formed on a rack shaft 4 (axle), a nut 7 is engaged with the ball screw, and an armature winding 12 (winding) is Wire cylinder), and the commutator 13 to the nut 7 and the commutator 1
3 is pressed from a circumferential direction of the commutator 13 by a slider 14 (brush) housed in a holder 15, and a magnet 16 (permanent magnet) is arranged inside the armature winding 12. While supporting the slider 14, the nut 7, the armature winding 12,
Commutator 13 in rack housing 3 (motor housing)
This is a coreless motor for electric power steering covered with.

[0003]

However, in the above-described coreless motor for electric power steering, the armature winding 12 is rotated in a space enclosed by the rack housing 3,
Since the slider 14 is in contact with the commutator 13, heat generation of the commutator 13 and the slider 14 cannot be avoided, and there is a possibility that the life of the coreless motor may be reduced.
For example, if a heat radiating hole or the like is opened in the rack housing 3 in order to avoid heat generation of the commutator 13 and the slider 14, dust and mud enter the rack housing 3, which may cause a failure of the coreless motor. Become.

An object of the present invention is to provide a coreless motor for an electric power steering which can prevent heat generation of a commutator and a brush without opening a heat radiation hole or the like in a motor housing.

[0005]

In order to solve the above-mentioned problems, a first aspect of the present invention is a ball screw formed on an axle, a nut meshed with the ball screw, a cylinder attached to the nut, and a cylinder. A holding disk provided on the body, a winding cylinder having one end fitted to an outer peripheral portion of the holding disk, a commutator mounted on the holding disk, a brush for pressing the commutator, and an inner side of the winding cylinder. In a coreless motor for electric power steering, comprising a permanent magnet arranged, and a motor housing that supports these permanent magnets and brushes and covers a nut, a holding disk, a winding cylinder, and a commutator, a passage substantially parallel to an axle is formed in the holding disk. Drilling holes are formed in the cylinder from the center of the axle and substantially parallel to the radial axis, through which air is circulated into the motor housing. Characterized in that it was.

[0006] Through holes are formed in the holding disk substantially parallel to the axle, and through holes are formed in the cylinder from the center of the axle and substantially parallel to the radiation axis, and air is circulated through the through holes into the motor housing. By circulating air into the motor housing through the through-hole of the holding disk and the through-hole of the cylindrical body by rotating the winding cylinder, heat generation of the commutator and the brush is suppressed.

The second aspect of the present invention is characterized in that the through hole of the holding disk is a hole inclined at a predetermined angle with respect to the axle. By inclining the through hole of the holding disk at a predetermined angle with respect to the axle, air is positively circulated in the motor housing.

[0008] A third aspect of the present invention is characterized in that the through hole of the cylindrical body is a hole inclined at a predetermined angle with respect to the radiation axis. By inclining the through hole of the cylinder at a predetermined angle with respect to the radiation axis,
Actively circulate air through the motor housing.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a perspective view of a steering device equipped with a coreless motor for electric power steering according to the present invention. A steering device 10 as an electric power steering includes a coreless motor 30 for electric power steering that assists the steering force of a steering wheel 11.
(Hereinafter, abbreviated as “coreless motor”), which is an example of an electric power steering. The steering force of the steering wheel 11 is detected by a torque sensor 12, and the coreless motor 30 is controlled based on information from the torque sensor 12. It is provided with a controller 13 for controlling.

In the drawing, 14 is a battery, 15 is a steering shaft for supporting the steering wheel 11, 16 is a universal joint attached to the tip of the steering shaft, 17 is a tip shaft attached to the steering shaft 15 via the universal joint 16, 1
8 is a gear case, 19 is an axle, 21 and 21 are tie rods attached to the axle 19, and 22 and 22 are front wheels.

FIG. 2 is a sectional view of a main part of a steering device equipped with a coreless motor for electric power steering. Specifically, the steering device 10 includes the gear case 1
A pinion 24 formed on the tip shaft 17 and a rack 25 formed on the axle 19 are accommodated in the shaft 8, and the rotation of the pinion 24 is transmitted to the rack 25 so that the axle 19 can be moved right and left in the drawing. At this time, the steering torque of the steering wheel 11 (see FIG. 1) is assisted by transmitting the rotational torque of the coreless motor 30 to a ball screw 26 formed on the axle 19 via a thrust ball group 27 as a power transmission member. It is something to do. The tie rods 21 and 28 are attached to the axle 19.
Reference numeral 29 denotes a ball joint for connecting the ball screw 1 to the ball screw 26 via a thrust ball group 27.

FIG. 3 is a front sectional view of a coreless motor for electric power steering according to the present invention. The coreless motor 30 includes a ball screw 26 formed on the axle 19, a nut 29 meshed with the ball screw 26, a cylinder 46 attached to the nut 29, and a holding disk 43 provided on the cylinder 46. Outer peripheral portion 43 of this holding disk 43
b, a winding cylinder 44 having one end 44a fitted thereto, a commutator 42 mounted on a holding disk 43, brushes 38, 38 pressing the commutator 42, and a permanent magnet disposed inside the winding cylinder 44. And a motor housing 35 that supports the permanent magnets 34 and the brushes 38 and 38 and covers the nut 29, the holding disk 43, the winding cylinder 44, and the commutator 42. Through hole 47 parallel to 19
... (... indicates a plurality, the same applies hereinafter) and open the cylinder 46
Through hole 49 substantially parallel to the radial axis from the center of axle 19
.. Are opened and air is circulated through the through holes 47,. The nut 29 is provided in the vicinity of the holding disk 43.

FIG. 4 is an exploded perspective view of a stator of the coreless motor for electric power steering according to the present invention. The stator 31 has a ball bearing 33 attached to one end 32 a of a fixed member 32 and an outer periphery 32 b of the fixed member 32. A permanent magnet 34 attached, a motor housing 35 accommodating the permanent magnet 34, the ball bearing 33 and the fixing member 32, a ball bearing 36 attached to the gear case 18 side, and a brush attaching base 37 attached to the gear case 18 side. And brushes 38, 38 attached to the brush attachment base 37. Reference numeral 18a denotes a flange portion of the gear case, and 35a denotes an edge portion 35a of the motor housing 35.

FIG. 5 is an exploded perspective view of a rotor of the coreless motor for electric power steering according to the present invention. In the rotor 41, a commutator 42 is mounted on a holding disk 43, and the holding disk 43 is connected to one end of a winding cylinder 44. The thrust ball group 27 shown in FIG. 3 is inserted into the cylindrical body 46 by fitting the thrust ring 45 to the other end 44b of the winding cylinder 44 and the cylindrical body 46 to the holding disk 43. A nut 29 to be fitted to the ball screw 26 via the nut 29 is attached. The nut 29 is provided in the vicinity of the holding disk 43. Commutator 4
Reference numeral 2 denotes a set of commutator pieces 42a arranged in a disc shape on one side surface 43a of the holding disk 43, and escape holes 48 to be fitted into a plurality of through holes 47 of the holding disk 43.・ It is equipped with.

FIG. 6 is a view taken along line 6-6 of FIG. 3, showing one side surface 43a of the holding disk 43. Holding disk 43
Is a disk-shaped member that supports one end 44a of the winding cylinder 44 and holds the commutator pieces 42a... (See FIG. 5), and is a member that has a plurality of through holes 47. . 43b indicates an outer peripheral portion of the holding disk 43.

FIG. 7 is a sectional view taken along the line 7-7 in FIG. 6, and the through hole 47 is formed on one side surface 43a of the holding disk 43 and is formed obliquely in the circumferential direction of the holding disk 43 so that the rotor 41 is formed. (See FIG. 5). That is, the coreless motor 30 (see FIG. 3)
7 are inclined at a predetermined angle with respect to the axle 19, so that the air is positively supplied to the motor housing 35 (see FIG. 3).
It is intended to be circulated inside. As a result, the effect of cooling the commutator 42 and the brushes 38, 38 shown in FIG. 3 can be improved.

FIG. 8 is a sectional view taken along line 8-8 of FIG. 3. The cylindrical body 46 is rotated by a ball screw 26 formed on the axle 19 via a thrust ball group 27 as shown in FIG. A member provided with a nut 29 for transmitting torque, wherein a radial axis A
Are formed so as to be inclined with respect to. That is, the coreless motor 30 (see FIG. 3) actively inflates the motor housing 35 (see FIG. 3) by inclining the through holes 49 of the cylindrical body 46 at a predetermined angle with respect to the radiation axis A. It circulates inside. As a result, the commutator 42 and the brush 3 shown in FIG.
8, 38 can be improved in cooling effect.

Next, the operation of the above-described coreless motor 30 will be described. 9 to 12 are process diagrams showing an example of an assembly procedure of the coreless motor 30. First, an assembly procedure of the coreless motor 30 will be described. FIGS. 9A and 9B are first assembly process diagrams of the coreless motor for electric power steering according to the present invention, and in FIG.
2, a ball bearing 33 is attached to one end 32a, and a permanent magnet 34 is attached to the outer periphery 32b of the fixing member 32. The permanent magnet 34, the ball bearing 33, and the fixing member 3
2 is stored in the motor housing 35. That is,
In (b), the fixing member 32 and the ball bearing 3
3. The permanent magnet 34 is moved from the axle direction to the motor housing 35.
To form a stator subassembly 51.

FIGS. 10A and 10B are second assembly process diagrams of the coreless motor for electric power steering according to the present invention. In FIG.
3 and the holding disk 43 is attached to the winding cylinder 44.
And the other end 44a of the winding cylinder 44
The thrust ring 45 is fitted to b. That is,
In (b), the commutator 42, the holding disk 43 and the thrust ring 45 are assembled to the winding cylinder 44 from the axle direction to form the rotor sub-assembly 52.

FIGS. 11 (a) and 11 (b) are diagrams showing a third assembly process of the coreless motor for electric power steering according to the present invention. In FIG. 11 (a), the ball screw 26 is passed through the gear case 18 and the rotor 41 ( 3) Side cylinder 46
A nut 29 is fitted to the ball screw 26 via a thrust ball group 27 (see FIG. 3), a ball bearing 36 is attached to the gear case 18, and a brush 38 is attached to the flange portion 18a of the gear case 18. ,
The brush mounting base 37 to which 38 has been mounted is mounted.
That is, in (b), the ball bearing 36, the cylindrical body 46,
Nut 29, brush mounting base 37 and brush 38,
The gear case sub-assembly 53 is formed by attaching 38 from the axle direction.

FIG. 12 is a fourth assembly process diagram of the coreless motor for electric power steering according to the present invention. The rotor sub-assembly 52 is assembled to the gear case sub-assembly 53 from the axle direction, and the rotor sub-assembly 52 and the gear case are assembled. The stator sub-assembly 51 is assembled to the sub-assembly 53 from the axle direction, and the edge 35a of the motor housing 35 is caulked to the flange 18a of the gear case 18 to complete the assembly of the coreless motor 30. That is, the commutator 42 is attached to one side surface 43a of the holding disk 43, and the commutator 42 is pressed against the commutator 42 from the axle direction by the brushes 38, 38. be able to. As a result, the assemblability of the coreless motor 30 can be improved, and the manufacturing cost of the coreless motor 30 can be reduced by shortening the assembling time.

FIGS. 13 (a) and 13 (b) are explanatory views of a first operation of the coreless motor for electric power steering according to the present invention, wherein (a) shows a comparative example and (b) shows an embodiment. In (a), the coreless motor 100 of the comparative example
Is provided such that a commutator 101 is provided along an axle 102, brushes 103 and 103 are arranged around the commutator 101, and the commutator 101 is pressed from the circumference of the axle 102 toward the center by the brushes 103 and 103. And axle 10
The coreless motor 100 is attached to the ball screw 105 formed in FIG.
Holding the nut 107 for transmitting the rotational torque of the disk 1
The coreless motor 100 is provided on the thrust ring 109 side opposite to the motor 08. Here, the entire length of the coreless motor 100 is referred to as L1.

In (b), the coreless motor 30 of the embodiment has a holding disk 43 fitted to one end 44a of a winding cylinder 44, and a nut 29 disposed near the holding disk 43 and in a cylindrical body 46. By engaging the nut 29 with the ball screw 26, the total length of the coreless motor 30 can be shortened. Further, by attaching the commutator 42 to one side surface 43a of the holding disk 43 and pressing the commutator 42 from the axle direction with the brushes 38, 38, the total length of the coreless motor 30 can be further reduced.
Here, assuming that the total length of the coreless motor 30 is L2, the total length L2 is the total length L1 of the coreless motor 100 shown in FIG.
(L2 <L1).

That is, the outer peripheral portion 43 b of the holding disk 43 is fitted to one end of the winding cylinder 44, the nut 29 is arranged near the holding disk 43 and in the cylinder 46, and the nut 29 is attached to the ball screw 26. The total length of the coreless motor 30 is shortened by meshing. That is, the coreless motor 30 can be a compact motor.

FIGS. 14A and 14B are views for explaining a second operation of the coreless motor for electric power steering according to the present invention. In (a), when the rotor 41 is rotated clockwise as indicated by an arrow, a flow of air from the inside to the outside is generated in the through hole 49 of the cylindrical body 46 as indicated by the arrow, and the air flows through the through hole 47 of the holding disk 43. As shown by an arrow, a flow of air is generated from the front side of the drawing to the back side of the drawing. As a result, (b)
At the time, a circulating flow 54 is generated between the through hole 47 of the holding disk 43 and the through hole 49 of the cylindrical body 46. This allows
The frictional heat generated between the commutator 42 and the brushes 38, 38 can be cooled. As a result, the coreless motor 30
(See FIG. 3) can be extended.

FIGS. 15A and 15B are views for explaining a third operation of the coreless motor for electric power steering according to the present invention. 7A, when the rotor 41 is rotated counterclockwise as indicated by an arrow, a flow of air from the outside to the inside is generated in the through hole 49 of the cylindrical body 46 as indicated by the arrow, and the through hole 47 of the holding disk 43 is formed. As shown by an arrow, a flow of air is generated from the back side of the drawing to the front side of the drawing. as a result,
In (b), the through-hole 4 of the holding disk 43 is indicated by an arrow.
A circulating flow 55 opposite to the circulating flow 54 shown in FIG. 14 is generated between 7 and the through hole 49 of the cylindrical body 46. This allows
The frictional heat generated between the commutator 42 and the brushes 38, 38 can be cooled.

In the embodiment, as shown in FIG. 3, a commutator 42 is provided on one side surface 43a of the holding disk 43, that is, outside the winding cylinder 44, and a brush 38,
Although the pressure is applied to the commutator 38, the present invention is not limited to this. A commutator may be provided inside the winding cylinder and the brush may be pressed against the commutator. In the embodiment, as shown in FIG. 3, the nut 29 is provided on the holding disk 43 side to transmit the rotational torque to the ball screw 26. However, the present invention is not limited to this. What is necessary is just to be provided in arbitrary positions. Further, in the embodiment, as shown in FIG. 3, a commutator is attached to one side surface of the holding disk, and the commutator 42 is pressed from the axle direction by the brushes 38, 38. However, the present invention is not limited to this. A commutator may be provided along the axle, a brush may be arranged around the commutator, and the commutator may be pressed with a brush along the radial axis of the axle.

[0028]

According to the present invention, the following effects are exhibited by the above configuration. According to the first aspect, through holes are formed in the holding disk substantially parallel to the axle, and through holes are formed in the cylinder from the center of the axle and substantially parallel to the radial axis, and air is circulated through the through holes into the motor housing. As a result, heat generation of the commutator and the brush can be prevented. As a result, the life of the coreless motor for electric power steering can be extended.

According to the second aspect, the through hole of the holding disk is inclined at a predetermined angle with respect to the axle, so that the air can be positively circulated in the motor housing. As a result,
The cooling effect of the commutator and the brush can be improved.

In the third aspect, since the through hole of the cylindrical body is inclined at a predetermined angle with respect to the radiation axis, air can be circulated in the motor housing positively. As a result, the effect of cooling the commutator and the brush can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a steering device equipped with a coreless motor for electric power steering according to the present invention.

FIG. 2 is a sectional view of a main part of a steering device equipped with a coreless motor for electric power steering.

FIG. 3 is a front sectional view of a coreless motor for electric power steering according to the present invention.

FIG. 4 is an exploded perspective view of a stator of the coreless motor for electric power steering according to the present invention.

FIG. 5 is an exploded perspective view of a rotor of the coreless motor for electric power steering according to the present invention.

FIG. 6 is a view taken along line 6-6 of FIG. 3;

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

8 is a sectional view taken along line 8-8 in FIG. 3;

FIG. 9 is a first assembly process diagram of the coreless motor for electric power steering according to the present invention.

FIG. 10 is a second assembly process diagram of the coreless motor for electric power steering according to the present invention.

FIG. 11 is a third assembly process diagram of the coreless motor for electric power steering according to the present invention.

FIG. 12 is a fourth assembly process diagram of the coreless motor for electric power steering according to the present invention.

FIG. 13 is a diagram illustrating a first operation of the coreless motor for electric power steering according to the present invention.

FIG. 14 is a diagram illustrating a second operation of the coreless motor for electric power steering according to the present invention.

FIG. 15 is a diagram illustrating a third operation of the coreless motor for electric power steering according to the present invention.

[Explanation of symbols]

19 ... axle, 26 ... ball screw, 29 ... nut, 30 ...
Coreless motor, 34 permanent magnet, 35 motor housing, 38 brush, 42 commutator, 43 holding disk, 43b outer peripheral part, 44 winding coil, 44a one end, 46 cylinder, 47 holding Disc through-hole, 49 ... cylindrical body through-hole, A: radiation axis.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiromi Nozawa 112-1, Hagadai, Haga-cho, Haga-gun, Tochigi F-term in Showa Tochigi Development Center Co., Ltd. 3D033 CA02 CA04 CA31 5H607 AA11 AA12 BB04 BB14 BB23 CC01 CC03 CC05 CC09 DD01 DD02 DD03 EE52 FF22 GG04 JJ04 5H609 BB06 BB12 PP02 PP05 PP06 PP07 PP09 PP11 PP13 PP17 QQ02 QQ10 QQ12 QQ18 RR06 RR36 5H623 AA05 AA08 BB07 GG12 GG16 HH02 HH06 HH10 JJ05 LL

Claims (3)

[Claims] 1. A ball screw formed on an axle, a nut engaged with the ball screw, a cylinder attached to the nut, a holding disk provided on the cylinder, and one end provided on an outer peripheral portion of the holding disk. , A commutator attached to the holding disk, a brush pressing the commutator, a permanent magnet disposed inside the winding cylinder, and supporting these permanent magnets and brushes. A coreless motor for electric power steering, comprising a nut, a holding disk, a winding cylinder, and a motor housing covering a commutator, wherein a through-hole substantially parallel to an axle is formed in the holding disk, and a center of the axle is formed in the cylindrical body. And through holes substantially parallel to the radiation axis, and air is circulated through the through holes in the motor housing. Coreless motor for power steering. 2. The coreless motor for electric power steering according to claim 1, wherein the through hole of the holding disk is a hole inclined at a predetermined angle with respect to an axle. 3. The coreless motor for an electric power steering according to claim 1, wherein the through hole of the cylindrical body is a hole inclined at a predetermined angle with respect to the radiation axis.