JP2002262504A - Motor-driven power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten a weight by reducing the number of part items of a motor, additionally eliminate a bolt tightening part for fixing the motor to a housing and a seal part, in a motor-driven power steering device. SOLUTION: In this motor-driven power steering device 10, a brush holder 62 is faucet-connected to a motor case 31 of the motor 30, and with it being in a condition of a faucet connection of the brush holder 62 and the housing 11B, the motor case 31 is fixed to the housing 11B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric power steering apparatus.

[0002]

2. Description of the Related Art An electric power steering apparatus is disclosed in
As described in JP-A-11-342856, an electric motor is fixed to a housing, an assist shaft of a steering device is supported on the housing, an assist shaft is connected to a rotation shaft of the electric motor, and the torque of the electric motor is transmitted to the steering device. Tell and assist steering.

In the prior art, as a structure for fixing an electric motor to a housing, an end plate is spigot-coupled to a motor case of the electric motor and bolted, and the end plate is spliced to a housing and bolted. In addition, the motor case of the electric motor and the housing are centered and assembled. Also, the rotary shaft of the electric motor and the assist shaft are spline-coupled, and both ends of the rotary shaft are supported at two points by bearings provided on the motor case and the end plate, respectively, and both ends of the assist shaft are provided on the housing. The bearing is supported at two points.

[0004]

The prior art has the following problems. An end plate is interposed for centering and assembling the motor case and the housing of the electric motor.
It becomes heavy.

[0005] Bolts are fastened to the motor case and the end plate and bolts are fastened to the housing and the end plate, so that two bolt fastening portions and two sealing portions are required.

As a support structure for a rotating shaft of an electric motor,
Since bearings are used at both ends of the rotating shaft, the number of parts of the electric motor is large and the weight is large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric power steering apparatus in which the number of parts of the electric motor is reduced, the weight of the electric motor is reduced, and the number of bolts and seals for fixing the electric motor to the housing is reduced. .

[0008]

According to a first aspect of the present invention, there is provided an electric motor in which an electric motor is fixed to a housing, an assist shaft of a steering device is supported on the housing, and an assist shaft is connected to a rotating shaft of the electric motor. In a power steering device, a brush holder is spigot-coupled to a motor case of an electric motor, and the motor case is fixed to the housing with the brush holder spigot-coupled to the housing.

According to a second aspect of the present invention, there is provided an electric power steering apparatus comprising an electric motor fixed to a housing, an assist shaft of a steering device supported on the housing, and an assist shaft connected to a rotating shaft of the electric motor. The motor case is fixed to the housing while the magnet holder is spigot-coupled to the motor case of the motor and the magnet holder is spigot-coupled to the housing.

According to a third aspect of the present invention, in addition to the first or second aspect, the rotating shaft of the electric motor and the assist shaft are connected by means of a spigot connecting means, and only one end of the rotating shaft is supported by the motor case. The other end of the shaft has an unsupported structure.

[0011]

According to the first aspect of the present invention, the following operations are provided. As the structure for centering and assembling the motor case of the electric motor to the housing, the brush holder, which is essential for the electric motor, is used, and the end plate is not required. it can.

Since the motor case of the electric motor is directly fixed to the housing at only one place, the number of bolted parts and the number of sealing parts are reduced to only one, respectively, so that the assembling property and sealing property can be improved.

According to the second aspect of the present invention, the following operations are provided. As the structure for centering and assembling the motor case of the electric motor to the housing, the magnet holder required for the electric motor is used and no end plate is required, so the number of parts can be reduced, the weight can be reduced, and the assembly accuracy is secured. it can.

Since the motor case of the electric motor is directly fixed to the housing at only one location, the number of bolt fastening locations and the number of sealing locations are reduced to only one location each, thereby improving the assembling and sealing properties.

According to the third aspect of the invention, the following effects are obtained. As a structure for supporting the rotating shaft of the electric motor, only one end of the rotating shaft is supported, and the other end is spigot-coupled to the assist shaft of the steering device.
Further, the weight can be reduced, and the variation in rotation (due to the rotation center deviation) on the other end side of the rotating shaft can be suppressed to a minimum by the spigot connection.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view showing an electric power steering apparatus partially cut away, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a sectional view taken along the line III-III of FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2, FIG. 5 is a perspective view showing a magnet holder, FIG. 6 shows a brush holder, and FIG.
Is a front view, (B) is a side view, FIG. 7 shows a grommet,
(A) is a front view, (B) is a side view, (C) is a plan view, FIG. 8 is a side view showing a main part of FIG. 3, and FIG. 9 is a side view showing a modification of FIG.

As shown in FIGS. 1 and 2, the electric power steering apparatus 10 includes a gear housing 1 made of an aluminum alloy and fixed to a body frame or the like by a bracket (not shown).
1 (first to third gear housings 11A to 11C). A pinion shaft 14 is connected to a steering shaft 12 to which a steering wheel is coupled via a torsion bar 13. It is supported by the first gear housing 11A so as to be movable left and right. Steering shaft 12 and pinion shaft 14
Between them, a steering torque detecting device 17 is provided. still,
The steering shaft 12 and the pinion shaft 14 have bearings 12A, 1
It is supported by the gear housing 11 via 4A and 14B.

As shown in FIG. 2, the steering torque detector 17 includes two detection coils 17A surrounding a cylindrical core 17C engaged with the steering shaft 12 and the pinion shaft 14,
17B is provided in the third gear housing 11C. The core 17C is provided with a vertical groove 17E that engages with the guide pin 17D of the pinion shaft 14 so as to be movable only in the axial direction, and has a spiral groove 17G that engages with the slider pin 17F of the steering shaft 12. As a result, the steering torque applied to the steering wheel is applied to the steering shaft 12, and when a relative displacement in the rotational direction occurs between the steering shaft 12 and the pinion shaft 14 due to the elastic torsional deformation of the torsion bar 13, the steering shaft 12 The displacement of the pinion shaft 14 in the rotation direction causes the core 17C to be displaced in the axial direction, and the displacement of the core 17C changes the inductance of the detection coils 17A and 17B due to magnetic changes around the detection coils 17A and 17B. . That is, when the core 17C moves toward the steering shaft 12, the inductance of the detection coil 17A closer to the core 17C increases, and the inductance of the detection coil 17B closer to the core 17C decreases. Can be detected.

The rack shaft 1 in the first gear housing 11A
As shown in FIG. 2, a rack guide 19 is built in a cylinder portion 18 provided at a portion opposed to the pinion 15 with one end of the bush 6 interposed therebetween.
9A) is repelled toward the rack shaft 16 by a spring 21 supported on the back surface by a cap 20 attached to the cylinder portion 18 to press the rack 16A of the rack shaft 16 against the pinion 15 and to connect one end of the rack shaft 16 to the pinion 15. It is slidably supported. The other end of the rack shaft 16 is supported by a bearing 22. In the middle part of the rack shaft 16, left and right tie rods 23A, 23 are connected by connecting bolts 22A, 22B.
B is connected.

As shown in FIGS. 3 and 4, a motor case 31 of the electric motor 30 is fixed to the second gear housing 11B, and an assist shaft 33 is connected to a rotating shaft 32 of the electric motor 30 via a connector 80. The assist shaft 33 is connected to both ends of the second gear housing 11B by bearings 34 and 35 such as ball bearings. The inner ring of the bearing 34 is formed by the stopper ring 36A, and the outer ring is formed by the lock nut 36A.
B holds. A worm gear 37 is integrally provided at an intermediate portion of the assist shaft 33.
A worm wheel 38 meshing with 7 is fixed to an intermediate portion of the pinion shaft 14. The generated torque of the electric motor 30 is
The worm gear 37 and the worm wheel 38 mesh with each other, and the pinion 15 and the rack 16A mesh with each other.
6 is provided as a steering assist force, and the driver assists the steering force applied to the steering shaft 12.

Here, the electric motor 30 is configured as follows. That is, the electric motor 30 includes a cylindrical yoke 52 formed of a magnetic material such as iron, and a cylindrical yoke 52 formed of an insulating resin material forming magnet housing sections 53 </ b> B at a plurality of circumferential positions on the inner periphery of the yoke 52. A magnet holder 53 composed of a body 53A, a magnet 54 housed and positioned and held in a magnet housing section 53B of the magnet holder 53, and a nonmagnetic material press-fitted inside the magnet 54 positioned and held by the magnet holder 53. The stator 51 includes a magnet cover 55 (not shown) formed of an extremely thin plate.

The electric motor 30 has a rotor 56 inserted inside the stator 51 and fixed to the rotating shaft 32. The rotor 56 includes an amateur core 57 and a commutator 58 provided on the outer periphery of the rotating shaft 32.

The electric motor 30 is composed of a brush 61 contacted with a commutator 58 of a rotor 56 and a short cylindrical body 62A formed of an insulating resin material forming a brush holding portion 62B for positioning and holding the brush 61. A brush holder 62. The electric motor 30
Is a brush 61 positioned and held by a brush holder 62.
A connection terminal 63A is connected through a pigtail to the brush holder 62. The power supply connector 63 is formed integrally with the brush holder 62 by an insulating resin material containing the connection terminal 63A.

When electric power is supplied from the brush 61 to the armature 57 via the commutator 58 of the rotor 56, the magnetic force lines of the armature 57
By cutting off the magnetic field generated by the magnet 54, the rotor 56 rotates.

However, the electric motor 30 has the following characteristic configuration. (1) In the electric motor 30, the yoke 52 is a cylindrical body with one end opened and the other end closed, and the yoke 52 is used as the motor case 31. The yoke 52 has one end flange portion 52A fixed to the housing 11B and the other end closing portion 52B.

(2) As shown in FIG. 5, the magnet holder 53 is a cylindrical body 53A having a magnet accommodating section 53B.
The outer periphery of the tubular body 53A is spigot-coupled to the yoke 52, and the engaging portion 53C that engages with the engaging portion 62C of the brush holder 62 is connected to the outer periphery of the tubular body 53A so that the circumferential specific position And the outer periphery of the engaging portion 53C can be spigot-coupled to the housing 11B.

(3) As shown in FIG. 6, the brush holder 62 forms a short cylindrical body 62A having a brush holding portion 62B, and the brush holding portions 62B are formed at a plurality of circumferential positions on the inner periphery of the short cylindrical body 62A. The spring 6 is attached to the brush holding portion 62B.
4. The brush 61 is inserted, and the brush 61 is pressed against the commutator 58 of the rotor 56 by the spring force of the spring 64. The brush holder 62 has an outer peripheral end of the short cylindrical body 62A spigot-coupled to a container 52 constituting the motor case 31 and the other end of the outer peripheral side of the short cylindrical body 62A is connected to the housing 1.
1B can be spliced.

The brush holder 62 has a concave engaging portion 62C at a specific circumferential position on one end and a locking portion 62D at a specific circumferential position on the other end. By engaging the engaging portion 53C of the magnet holder 53 with the engaging portion 62C of the brush holder 62, the brush 61 held by the brush holder 62 with respect to the magnet 54 of the stator 51 positioned by the magnet holder 53.
Eliminating the phase shift, rotation performance of the electric motor 30 is prevented from becoming different things in the forward direction and reverse direction, to avoid performance degradation. Further, the locking portion 6 of the brush holder 62
By locking the 2D to a locking portion 65A formed concavely at a specific circumferential position on the inner side of the spigot coupling portion 65 of the housing 11B, the circumferential mounting position of the brush holder 62 can be easily and reliably positioned. .

(4) The grommet 66 is provided in the brush holder 62.
There is assembled is deposited. The grommet 66 is a connection portion between the housing 11B and the motor case 31 (yoke 52), and is a connector seal portion 6 which is mounted on a connector insertion portion 68 formed by cutting out a flange portion 67 of the housing 11B.
6A and an O-ring 66B that is loaded into a ring groove 69 formed in the flange 67 of the housing 11B. The brush holder 62 includes a connector seal portion 66A of the grommet 66 on the power supply connector 63 and an O-ring 6 of the grommet 66 on the short cylindrical body 62A of the brush holder 62.
6B, the housing 11B and the motor case 3
1 (yoke 52) is assembled in a liquid-tight manner at the connection portion.

(5) According to the above (2) to (4), the electric motor 30
Is fixed to the housing 11B as follows.

The grommet 66 is attached to the brush holder 62. The cylindrical body 53A of the magnet holder 53 is spigot-coupled to the motor case 31 (yoke 52) of the electric motor 30. Subsequently, one end side of the short cylindrical body 62A of the brush holder 62 is spliced to the motor case 31 (yoke 52) (FIG. 3). At this time, the engaging portion 62 of the brush holder 62
C is engaged with the engaging portion 53C of the magnet holder 53.

The engaging portion 53C of the magnet holder 53 is spigot-coupled to the spigot joint 65 of the housing 11B (FIG. 4). At the same time, the short cylindrical body 6 of the brush holder 62
The other end of 2A is connected to the spigot joint 65 of the housing 11B.
(Fig. 3). At this time, the locking portion 62D of the brush holder 62 is fixed to the locking portion 65A of the housing 11B.
Is locked.

At the same time as described above, the connector seal 66A of the grommet 66 is connected to the flange 6 of the housing 11B.
The O-ring 66 </ b> B of the grommet 66 is sealed to the connector
B is loaded into the ring groove 69 provided in the flange 67 and is sealed between the flange 67 and the flange 52 </ b> A of the yoke 52.

The motor case 31 (yoke 52) of the electric motor 30 is composed of the motor case 31 (yoke 52) using the above-described magnet holder 53 and the housing 1.
The flange portion 52 of the yoke 52 is centered on the housing 11B by the spigot connection with the housing 11B by the spigot connection with the housing 11B and the spigot connection between the motor case 31 (yoke 52) and the housing 11B using the brush holder 62.
A is fastened and fixed to the flange 67 of the housing 11B.

Next, the rotating shaft 32 of the electric motor 30 is supported by the motor case 31 as follows. (1) The rotating shaft 32 and the assist shaft 33 of the electric motor 30 are spliced and connected to the cylindrical connector 80, and only one end of the rotating shaft 32 is connected to the other end closing portion 52B of the motor case 31 (yoke 52). It was supported by a bearing 71 provided at the center, and the other end of the rotating shaft 32 was unsupported.

Specifically, as shown in FIG. 8, a fitting shaft (or fitting hole) 32A provided at the tip of the rotary shaft 32 of the electric motor 30 is pressed into a hole 81 of the connecting body 80. Fixed,
It is connected so as to be able to rotate integrally without any play Also, on the same axis as the rotating shaft 32, a fitting shaft (or fitting hole) 33 </ b> A provided at the tip of the assist shaft 33 is spliced into the hole 81 of the connecting body 80, and the fitting of the assist shaft 33 is performed. Coaxial part 33A
Of the fitting shaft (or fitting hole) 33B on the side of
Is splined (serrated).

Accordingly, the rotary shaft 32 and the assist shaft 33 of the electric motor 30 are coaxially connected by being spigot-coupled to the same hole 81 of the connecting body 80. As a result, the rotary shaft 3
2, the end on the side to which the connecting body 80 is coupled has an unsupported structure with no bearing interposed in the motor case 31, and both ends of the assist shaft 33 are connected to the housing 11B via the bearings 34 and 35 as described above. Supported, and only one end of the rotating shaft 32 is connected to the motor case 31 via the bearing 71 as described above.
Points were to be supported.

(2) Inside the connecting body 80 connecting the rotating shaft 32 of the electric motor 30 and the assist shaft 33, it is interposed between the end faces of the rotating shaft 32 and the assist shaft 33 where they abut each other.
An O-ring-shaped elastic body 90 sandwiched in the axial direction by both the rotating shaft 32 and the assist shaft 33 was provided.

As shown in FIG. 9, the elastic body 90 is interposed between the stopper ring 36A engaged with the assist shaft 33 and the end face of the connecting body 80 outside the connecting body 80, and And the assist shaft 33 may be squeezed in the axial direction.

At this time, the assist shaft 33 is
5, the rotating shaft 32 is pressed in the direction of the anti-assist shaft 33 by the elastic force of the elastic body 90, so that there is no play in the axial direction, and it is possible to prevent the occurrence of a tapping sound.

Therefore, according to the present embodiment, the following operations are provided. According to the first aspect of the invention, the following operations are provided. The motor case 31 of the electric motor 30 is
As a structure for centering and assembling on B, the magnet holder 53 and the brush holder 62 which are essential for the electric motor 30 are used, and no end plate is required. it can.

The motor case 31 of the electric motor 30 is directly fixed to the housing 11B at only one position, and the number of bolt fastening portions and the number of sealing portions are reduced to only one each, so that the assembling property and the sealing property are improved. Can be improved.

As a structure for supporting the rotating shaft 32 of the electric motor 30, only one end of the rotating shaft 32 is supported, and the other end is spigot-coupled to the assist shaft 33 of the steering device via the connector 80. The number of bearings used can be reduced, the weight can be further reduced, and the rotation variation (due to the rotation center deviation) on the other end side of the rotating shaft 32 can be suppressed to a minimum by the spigot connection.

Although the embodiments of the present invention have been described with reference to the drawings, the specific structure of the present invention is not limited to the embodiments, and changes in the design and the like may be made without departing from the gist of the present invention. The present invention is also included in the present invention. For example, as the structure for centering and assembling the motor case of the electric motor to the housing, only one of the brush holder and the magnet holder may be spigot-coupled to each of the motor case and the housing.

[0045]

As described above, according to the present invention, in the electric power steering apparatus, the number of parts of the electric motor is reduced, the weight is reduced, and a bolt fastening portion and a sealing portion for fixing the electric motor to the housing are provided. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing an electric power steering apparatus partially cut away.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

FIG. 5 is a perspective view showing a magnet holder.

FIG. 6 shows a brush holder, (A) is a front view,
(B) is a side view.

FIG. 7 shows a grommet, (A) is a front view,
(B) is a side view, and (C) is a plan view.

FIG. 8 is a side view showing a main part of FIG. 3;

FIG. 9 is a side view showing a modification of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electric power steering device 11B Housing 30 Electric motor 31 Motor case 32 Rotating shaft 33 Assist shaft 53 Magnet holder 62 Brush holder 80 Connecting body (inlay connecting means)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D033 CA02 5H605 AA02 AA08 BB05 BB09 BB17 CC06 CC07 CC08 DD09 DD16 EA23 EB10 EB12 EC02 EC08 5H613 AA02 AA03 BB04 BB15 BB28 GA12 GA17 GB09 KK05 KK10 PP02 PP07

Claims (3)

[Claims] 1. An electric power steering apparatus comprising an electric motor fixed to a housing, an assist shaft of a steering device supported on the housing, and an assist shaft connected to a rotating shaft of the electric motor. An electric power steering device, comprising: a motor case fixed to a housing in a state where the brush holder is spigot-coupled and the brush holder is spigot-coupled to the housing. 2. An electric power steering apparatus comprising an electric motor fixed to a housing, an assist shaft of a steering device supported on the housing, and an assist shaft connected to a rotating shaft of the electric motor. An electric power steering apparatus comprising: a motor holder fixed to a housing in a state where a magnet holder is spigot-coupled and a magnet holder is spigot-coupled to the housing. 3. The rotating shaft of an electric motor and an assist shaft are connected by spigot coupling means, only one end of the rotating shaft is supported by a motor case, and the other end of the rotating shaft is unsupported. 3. The electric power steering device according to 2.