JP4709435B2 - Electric power steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric power steering apparatus.
[0002]
[Prior art]
As described in JP-A-9-84300, an electric power steering device connects an assist shaft of a steering device to a rotating shaft of an electric motor, and a brush holder at a connection portion between a housing of the steering device and a motor case of the electric motor. The brush holder is disposed around the rotating shaft of the electric motor, the brush is held on the brush holder, and the brush is brought into contact with a commutator provided on the outer periphery of the rotating shaft of the electric motor.
[0003]
[Problems to be solved by the invention]
In the above-described electric power steering apparatus, the brush holder is inserted into an insertion recess provided in the housing and is held by a motor case fastened to the housing, and a protruding power supply connector is integrated with the cylindrical portion of the brush holder. It is necessary to make the lead wire connection port of the power feeding connector face the opening cut out in the housing.
[0004]
At this time, in the prior art, a seal rubber to be loaded on the outer periphery of the power supply connector is integrally formed on an O-ring interposed between a fastening portion of the mating surface of the housing and the mating surface of the motor case, and this seal rubber is formed in the notch of the housing. It can be loaded into the opening (Japanese Patent Laid-Open No. 63-56142).
[0005]
However, in the case where the seal rubber mounted on the outer periphery of the power supply connector is loaded into the notch opening of the housing and the O-ring is interposed between the mating surface of the housing and the mating surface of the motor case, the sealing property of the power supply connector by the seal rubber is used. Is bad. This is because the fastening force reaches the part of the entire circumference of the seal rubber mounted on the outer periphery of the power supply connector that is located on the side perpendicular to the direction of the fastening force acting between the housing and the motor case (the central axis direction of the electric motor). Therefore, in order to compress this portion between the outer periphery of the power supply connector and the notch opening of the housing by the fastening force, high component accuracy and seal tightening allowance setting management are required, and assembly efficiency is poor.
[0006]
An object of the present invention is to improve the sealing performance between a motor case and a housing, and the sealing performance between a power feeding connector and a housing integrated with a brush holder, in the electric motor of the electric power steering apparatus.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, the assist shaft of the steering device is connected to the rotating shaft of the electric motor, the brush holder is provided at the connecting portion between the housing of the steering device and the motor case of the electric motor, and the brush is disposed around the rotating shaft of the electric motor. In an electric power steering apparatus in which a holder is disposed, the brush is held by the brush holder, and the brush is brought into contact with a commutator provided on the outer periphery of the rotating shaft of the electric motor, a brush holder insertion recess is provided in the housing, and the brush is provided in the recess. When the holder is inserted and the brush case is held by the motor case fastened to the housing, the power supply connector protrudes from the cylindrical portion of the brush holder and is provided integrally, and the recess is formed around the lead wire connection port of the power supply connector. An inclined seal surface that is inclined with respect to the insertion direction is formed, and the inclined seal of the power feeding connector is formed in the insertion recess of the housing. An inclined seal portion is formed to make contact with the center of the inclined seal portion, and a through-hole is formed in the center of the inclined seal portion so that the lead wire connection port faces the sealing material. And a sealing material is provided at the fastening portion between the mating surface of the housing and the mating surface of the motor case.
[0008]
According to a second aspect of the present invention, in the first aspect of the present invention, the mating surface of the housing and the mating surface of the motor case are made flat, and a sealing material made of an O-ring is provided therebetween.
[0009]
According to a third aspect of the present invention, in addition to the first aspect of the present invention, the inclined sealing portion of the housing and the inclined sealing surface of the power feeding connector are made flat, and a sealing material made of an O-ring is provided therebetween.
[0010]
[Action]
The invention according to claim 1 has the following effect (1).
(1) The fastening force between the housing and the motor case extends over the entire circumference of the sealing material at the fastening portion between the housing and the motor case, and also extends over the entire circumference of the sealing material at the contact portion between the housing and the power supply connector. The material can be sufficiently compressed by the fastening force.
[0011]
The invention according to claim 2 has the following effect (2).
(2) The mating surface of the housing and the mating surface of the motor case were made flat, and a sealing material consisting of an O-ring was provided between them. Accordingly, the O-ring is clamped between the flat surfaces, and the sealing performance between the motor case and the housing can be improved.
[0012]
According to the invention of claim 3, the following effect (3) is obtained.
(3) The inclined seal portion of the housing and the inclined seal surface of the power supply connector are made flat, and a seal material made of an O-ring is provided between them. Therefore, the O-ring is clamped between the flat surfaces, and the sealing performance between the power supply connector and the housing can be improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
1 is a partially cutaway front view of the electric power steering apparatus, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 5 is an arrow view along line IV-IV in FIG. 3, FIG. 5 is an arrow view along line V-V in FIG. 3, FIG. 6 shows a brush holder, (A) is a partially broken side view, (B ) Is a rear view, and (C) is a plan view.
[0014]
The electric power steering apparatus 10 includes an aluminum alloy gear housing 11 (first to third gear housings 11A to 11C) fixed to a vehicle body frame or the like by a bracket (not shown) as shown in FIGS. . A pinion shaft 14 is connected to a steering shaft 12 to which a steering wheel is coupled via a torsion bar 13. A pinion 15 is provided on the pinion shaft 14. The first gear housing 11A is supported so as to be movable left and right. A steering torque detecting device 17 is provided between the steering shaft 12 and the pinion shaft 14. The steering shaft 12 and the pinion shaft 14 are supported by the gear housing 11 via bearings 12A, 14A, and 14B.
[0015]
As shown in FIG. 2, the steering torque detection device 17 includes two detection coils 17A and 17B surrounding a cylindrical core 17C engaged with the steering shaft 12 and the pinion shaft 14 in the third gear housing 11C. Yes. The core 17C includes 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 includes a spiral groove 17G that engages with the slider pin 17F of the steering shaft 12. As a result, a 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 elastic torsional deformation of the torsion bar 13, The displacement in the rotational direction of the pinion shaft 14 causes the core 17C to be displaced in the axial direction, and the inductance of the detection coils 17A and 17B due to the magnetic change around the detection coils 17A and 17B due to the displacement of the core 17C changes. . That is, when the core 17C moves to the steering shaft 12 side, the inductance of the detection coil 17A closer to the core 17C increases, and the inductance of the detection coil 17B farther away from the core 17C decreases. Can be detected.
[0016]
As shown in FIG. 2, a rack guide 19 is built in a cylinder portion 18 provided in a portion facing the pinion 15 across one end of the rack shaft 16 in the first gear housing 11A. 19A) is springed toward the rack shaft 16 by a spring 21 supported on the back surface by a cap 20 attached to the cylinder portion 18, and the rack 16A of the rack shaft 16 is pressed against the pinion 15 and one end of the rack shaft 16 is Support slidably. The other end side of the rack shaft 16 is supported by the bearing 22. Further, the left and right tie rods 23A and 23B are connected to the intermediate portion of the rack shaft 16 by connecting bolts 22A and 22B.
[0017]
As shown in FIG. 3, the motor case 31 of the electric motor 30 is fixed to the second gear housing 11B, and the assist shaft 33 is coupled to the rotating shaft 32 of the electric motor 30 via a connecting body 34 (torque limiter 34A). The rotating shaft 32 is supported at one end by the motor case 31 by a bearing 40 such as an angular ball bearing, and the assist shaft 33 is supported at both ends by the second gear housing 11B by bearings 41 and 42 such as ball bearings. A worm gear 37 is integrally provided at an intermediate portion of the assist shaft 33, and a worm wheel 38 meshing with the worm gear 37 is fixed to the intermediate portion of the pinion shaft 14. The generated torque of the electric motor 30 is applied as a steering assist force to the rack shaft 16 through the meshing of the worm gear 37 and the worm wheel 38, and the meshing of the pinion 15 and the rack 16A, and the driver imparts the torque to the steering shaft 12. Assist the steering force to do.
[0018]
Here, the electric motor 30 is configured as follows.
That is, as shown in FIG. 3, the electric motor 30 includes a cylindrical yoke 52 formed of a magnetic material such as iron, and an insulating resin material that forms magnet housing sections at a plurality of circumferential positions on the inner periphery of the yoke 52. A magnet holder 53 formed of a cylindrical body, a magnet 54 accommodated in a magnet accommodating section of the magnet holder 53 and positioned and held, and a non-pressed fit inside the magnet 54 positioned and held in the magnet holder 53 It has a stator 51 composed of a magnet cover 55 (not shown) formed of an extremely thin plate of magnetic material.
[0019]
Further, the electric motor 30 has a rotor 56 that is inserted inside the stator 51 and fixed to the rotary shaft 32. The rotor 56 includes an armature core 57 and a commutator 58 provided on the outer periphery of the rotating shaft 32.
[0020]
In addition, the electric motor 30 is provided with a brush holder 60 made of an injection molded body of an insulating resin at a connection portion between the housing 11B and the motor case 31 (yoke 52), and the brush holder 60 is disposed around the rotation shaft 32. A brush 70 (not shown) is held in the brush holder 60, and the brush 70 is brought into contact with the commutator 58 of the rotor 56.
[0021]
When the electric motor 30 is fed from the brush 70 through the commutator 58 of the rotor 56 to the armature core 57, the magnetic lines of force of the armature core 57 cut off the magnetic field generated by the magnet 54 of the stator 51, thereby rotating the rotor. 56 rotates.
[0022]
The brush holder 60 of the electric motor 30 is configured as follows (FIGS. 3 to 6).
As shown in FIG. 6, the brush holder 60 is composed of a bottomed short cylindrical body 61, and one end of the outer periphery of the short cylindrical body 61 is in-row coupled to a yoke 52 constituting the motor case 31, and the other end is It inserts into the insertion recessed part 80 provided in the housing 11B, and carries out inlay coupling | bonding. The housing 11B and the motor case 31 are fixed to each other by fastening the flange portion 102 of the motor case 31 to the flange portion 103 of the housing 11B with the bolt 101 in a state where the housing 11B and the motor case 31 are connected to each other by a brush holder 60 or the like.
[0023]
The short cylindrical body 61 of the brush holder 60 has an end plate 62 on the counter-rotor side and a cylindrical portion 63 provided on the outer periphery of the end plate 62, and convex portions 111 are provided at a plurality of positions in the circumferential direction of the cylindrical portion 63. The projection 111 is press-fitted over both the insertion recess 80 of the housing 11B and the motor case 31 (yoke 52), and the brush holder 60 is coaxially inserted into both the housing 11B and the motor case 31 (yoke 52). Join. On the inner surface of the end plate 62 and the cylindrical portion 63, a rib 112 (not shown) is provided on the back side corresponding portion of the convex portion 111.
[0024]
The brush holder 60 has an insertion hole 62A for the rotation shaft 32 on the central axis of the end plate 62 of the short cylindrical body 61, and the space on the assist shaft 33 side in the housing 11B is defined with respect to the space surrounding the commutator 58. Partition. As a result, the grease applied to the connecting body 34 of the rotating shaft 32 and the assist shaft 33 inside the housing 11B, the abrasion powder generated in the connecting body 34, and the like are prevented from reaching the commutator 58 side. The contact failure of the brush 70 is avoided.
[0025]
The brush holder 60 has a concave engaging portion 63A at a specific position in the circumferential direction of the cylindrical portion 63 of the short cylindrical body 61, and the convex engaging portion 53A provided on the magnet holder 53 is engaged with the concave engaging portion 63A. As a result, the phase difference between the magnet 54 held by the magnet holder 53 and the brush 70 held by the brush holder 60 is eliminated, and the rotation performance of the electric motor 30 is prevented from differing between the forward rotation direction and the reverse rotation direction. .
[0026]
As shown in FIGS. 4 and 6, the brush holder 60 has an end plate 62 erected and formed with brush holding portions 64 at a plurality of circumferential positions on the surface, and a brush 70 is slidably received in the brush holding portion 64. A brush hole 65 is provided. On the surface of the end plate 62, a post 66 for the spring 71 is formed upright on the side of the brush holding portion 64. The brush 70 receives the spring force of the spring 71, is guided by the brush hole 65, slides along the brush hole 65, and is pressed against the commutator 58 of the rotor 56. The electric motor 30 has a pigtail 72 connected to a brush 70 held by a brush holder 60 and a short cylindrical body 61 integrally provided with a power supply connector 67 containing a connection terminal to which the pigtail 72 is connected. Reference numeral 68 denotes a pigtail insertion fixing part integrally formed on the surface of the end plate 62.
[0027]
However, the electric motor 30 includes the brush holder 60 inserted into the insertion recess 80 of the housing 11B and is held by the motor case 31 (yoke 52) fastened to the housing 11B with the bolt 101 as follows. To do.
[0028]
(1) A power feeding connector 67 is provided so as to protrude from a part of the cylindrical portion 63 of the short cylindrical body 61 of the brush holder 60, and the insertion recess of the brush holder 60 is provided around the lead wire connection port 67A of the power feeding connector 67. An inclined seal surface 81 is formed which is inclined with respect to the insertion direction into 80 (a direction along the central axis of the cylindrical portion 63 coaxial with the rotation shaft 32 of the electric motor 30). The inclined sealing surface 81 forms a downward gradient in the direction toward the end plate 62 along the central axis of the cylindrical portion 63. The inclined sealing surface 81 is flat and includes an annular (endless circular) O-ring groove 81A.
[0029]
(2) A flat inclined seal portion 82 that abuts against the inclined seal surface 81 of the power supply connector 67 is provided in the insertion recess 80 of the housing 11B, and a lead wire connection port 67A of the power supply connector 67 is provided at the center of the inclined seal portion 82. The facing through-hole 82A is formed.
[0030]
(3) An O-ring 83 is interposed as a sealing material at the contact portion between the inclined seal portion 82 of the housing 11B and the inclined seal surface 81 of the power supply connector 67. The O-ring 83 is loaded in the O-ring groove 81A of the inclined sealing surface 81.
[0031]
(4) An O-ring 86 is used as a sealing material at the fastening portion by the bolt 101 of the planar mating surface 84 of the flange portion 102 orthogonal to the rotating shaft 32 of the motor case 31 and the planar mating surface 85 of the flange portion 103 of the housing 11B. Interpose. The O-ring 86 is loaded into an annular (endless circular) O-ring groove 85 </ b> A provided on the mating surface 85.
[0032]
According to this embodiment, there are the following operations.
(1) An O-ring 83 is provided as a sealing material at the contact portion between the inclined seal portion 82 of the housing 11B and the inclined seal surface 81 of the power supply connector 67, and the mating surface 85 of the housing 11B and the mating surface 84 of the motor case 31 are fastened. An O-ring 86 was provided as a sealing material at the part. Therefore, the fastening force between the housing 11B and the motor case 31 extends over the entire circumference of the O-ring 86 at the fastening portion between the housing 11B and the motor case 31, and the entire circumference of the O-ring 83 at the contact portion between the housing 11B and the power supply connector 67. Moreover, these O-rings 83 and 86 can be sufficiently compressed by the fastening force. Thereby, the sealing performance between the motor case 31 and the housing 11B and the sealing performance between the power supply connector 67 and the housing 11B integrated with the brush holder 60 can be improved.
[0033]
(2) The mating surface 85 of the housing 11B and the mating surface 84 of the motor case 31 are flat, and a sealing material made of an O-ring 86 is provided between them. Therefore, the O-ring 86 is clamped between the flat surfaces, and the sealing performance between the motor case 31 and the housing 11B can be improved.
[0034]
(3) The inclined sealing portion 82 of the housing 11B and the inclined sealing surface of the power feeding connector 67 are set to be a flat surface 81, and a sealing material comprising an O-ring 83 is provided therebetween. Therefore, the O-ring 83 is clamped between the flat surfaces, and the sealing performance between the power supply connector 67 and the housing 11B can be improved.
[0035]
Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and there are design changes and the like without departing from the scope of the present invention. Are also included in the present invention.
[0036]
【The invention's effect】
As described above, according to the present invention, with the electric motor of the electric power steering apparatus, the sealing performance between the motor case and the housing, and the sealing performance between the power feeding connector integrated with the brush holder and the housing can be improved.
[Brief description of the drawings]
FIG. 1 is a front view showing a partially broken electric power steering apparatus.
FIG. 2 is a sectional view taken along line II-II in FIG.
3 is a cross-sectional view taken along line III-III in FIG.
4 is an arrow view taken along the line IV-IV in FIG. 3;
5 is an arrow view taken along the line VV in FIG. 3. FIG.
6A and 6B show a brush holder, in which FIG. 6A is a partially broken side view, FIG. 6B is a rear view, and FIG. 6C is a plan view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electric power steering apparatus 11B Housing 30 Electric motor 31 Motor case 32 Rotating shaft 33 Assist shaft 58 Commutator 60 Brush holder 63 Cylindrical part 67 Power supply connector 67A Lead wire connection port 70 Brush 80 Insertion recessed part 81 Inclined seal surface 82 Inclined seal part 82A Through Port 83 O-ring (seal material)
84, 85 Mating surface 86 O-ring (seal material)

Claims (3)

Connect the assist shaft of the steering device to the rotating shaft of the electric motor,
A brush holder is provided at the connection between the housing of the steering device and the motor case of the electric motor, the brush holder is arranged around the rotating shaft of the electric motor,
In the electric power steering device that holds the brush in the brush holder and brings the brush into contact with a commutator provided on the outer periphery of the rotating shaft of the electric motor,
When the housing is provided with an insertion recess of the brush holder, the brush holder is inserted into the recess, and the brush holder is held by the motor case fastened to the housing,
The power supply connector protrudes from the cylindrical portion of the brush holder and is integrally provided, and an inclined sealing surface that is inclined with respect to the insertion direction into the recess is formed around the lead wire connection port of the power supply connector,
An inclined sealing portion that comes into contact with the inclined sealing surface of the power supply connector is provided in the insertion concave portion of the housing, and a through-hole through which the lead wire connection port of the power supply connector faces is formed at the center of the inclined seal portion,
An electric power steering characterized in that a seal material is provided at a contact portion between an inclined seal portion of a housing and an inclined seal surface of a power supply connector, and a seal material is provided at a fastening portion of the mating surface of the housing and the mating surface of the motor case. apparatus. The electric power steering apparatus according to claim 1, wherein the mating surface of the housing and the mating surface of the motor case are flat, and a seal member made of an O-ring is provided therebetween. The electric power steering apparatus according to claim 1, wherein the inclined seal portion of the housing and the inclined seal surface of the power supply connector are flat, and a seal member made of an O-ring is provided therebetween.

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