JP2008239133A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device capable of easily performing phasing of an output shaft of an electric motor and a worm shaft of a worm gear mechanism. <P>SOLUTION: In the electric power steering device, connection terminals 9c of the electric motor 9 and connection terminals 11a of a motor control unit 11 are superposed with and brought into surface contact with each other on a plane parallel with the motor output shaft 9b. The sum (L4 + L5 + L6) of a distance L4 from a housing side end face of a motor flange 9d formed on the electric motor 9 to a tip of the motor side connection terminal 9c, a distance L5 from a motor side end face of a motor mounting flange 3b formed on a housing 3 to a motor side end face of the worm shaft 10a and a distance L6 from the motor side end face of the motor mounting flange 3b to a tip of the control unit side connection terminal 11a is set smaller than a distance L7 from the housing side end face of the motor flange 9d to a tip face of the motor output shaft 9b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric power steering device that assists a steering operation of an automobile.

  As an electric power steering device for assisting steering operation of an automobile, for example, a device described in Patent Document 1 includes a motor housed in a rack case or a steering gear box, and a control board for driving and controlling the motor serves as a rack case or a steering gear. It is accommodated in a housing formed in the box. When the control board inserted into the housing from the opening of the housing comes into contact with the mounting boss formed on the bottom of the housing, the female terminal as the board side connection terminal provided on the control board is used as the motor side connection terminal. Since the male terminal is inserted and the motor and the control board are electrically connected, it is difficult to insert the male terminal into the female terminal unless the rigidity of the male terminal is increased. In addition, since the length of the male terminal has to be relatively long, there is a problem that the wiring resistance increases and it is easy to pick up electrical noise.

Therefore, in an electric power steering apparatus including a worm gear mechanism that transmits the rotational torque generated by the electric motor to the steering shaft at a reduced speed, the electric motor and a motor control unit that controls the electric motor are arranged in the gear housing that houses the worm gear mechanism. It has been proposed that a connection terminal of an electric motor and a connection terminal of a motor control unit are brought into surface contact (wrapping) in the vicinity of a motor mounting flange formed in a gear housing (see Patent Document 2).
JP 2005-329868 A Japanese Patent Application No. 2006-208954

  In such an electric power steering apparatus, it is not necessary to insert the connection terminal of the electric motor into the connection terminal of the motor control unit as described in Patent Document 1, so that the electric connection between the electric motor and the motor control unit is achieved. Work can be done easily. However, the motor side connection terminal and the control unit side connection terminal may wrap on a plane perpendicular to the output shaft of the electric motor, but the motor side connection terminal and the control unit side connection terminal are parallel to the output shaft of the electric motor. , The motor side connection terminal may wrap with the control unit side connection terminal before the output shaft of the electric motor is engaged with the worm shaft of the worm gear mechanism. There has been a problem that phase alignment becomes difficult.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide an electric power steering device capable of easily performing phase alignment between the output shaft of the electric motor and the worm shaft of the worm gear mechanism. There is.

  To achieve the above object, an electric power steering apparatus according to the first aspect of the present invention includes an electric motor, a worm gear mechanism that decelerates and transmits rotational torque generated by the electric motor to a steering shaft, and the worm gear mechanism. And a motor control unit attached to the gear housing, the motor side connection terminal of the electric motor and the control unit side connection terminal of the motor control unit formed in the gear housing. An electric power steering device that is in surface contact with the mounting flange in the vicinity of the mounting flange, wherein a distance from a housing side end surface of the motor flange formed on the electric motor to a tip of the motor side connection terminal is formed in the gear housing. Motor end face of the motor mounting flange The distance from the motor side end surface of the worm shaft of the worm gear mechanism to L5, the distance from the motor side end surface of the motor mounting flange to the tip of the control unit side connection terminal, L6, and the electric motor from the housing side end surface of the motor flange to the electric motor (L4 + L5 + L6) <L7, where L7 is the distance to the tip surface of the output shaft.

  The electric power steering device according to a second aspect of the present invention is the electric power steering device according to the first aspect, wherein the fitting length between the output shaft of the electric motor and the worm shaft of the worm gear mechanism is set to the motor of the electric motor. It is characterized by being made smaller than the inlay fitting length between the main body and the gear housing.

  In the electric power steering device according to the first aspect of the present invention, the distance L4 from the housing side end surface of the motor flange formed on the electric motor to the tip of the motor side connection terminal, the motor side of the motor mounting flange formed on the gear housing The sum of the distance L5 from the end surface to the motor side end surface of the worm shaft of the worm gear mechanism and the distance L6 from the motor side end surface of the motor mounting flange to the tip of the control unit side connection terminal is the output of the electric motor from the housing side end surface of the motor flange. By making the distance less than the distance L7 to the tip surface of the shaft, the motor side connection terminal does not overlap the control unit side connection terminal before the output shaft of the electric motor is fitted to the worm shaft of the worm gear mechanism. Therefore, the phase alignment between the output shaft of the electric motor and the worm shaft of the worm gear mechanism can be easily performed.

  In addition, the electric motor is moved in a direction other than the axial direction and the circumferential direction by fitting the output shaft of the electric motor with the worm shaft of the worm gear mechanism before the dynamic motor side connection terminal wraps with the control unit side connection terminal. Therefore, it is possible to prevent the electrical connection portion between the electric motor and the motor control unit from coming into contact with an extra portion to prevent the electrical connection portion from being damaged or deformed.

  In the electric power steering apparatus according to the second aspect of the invention, the fitting length between the output shaft of the electric motor and the worm shaft of the worm gear mechanism is made smaller than the inlay fitting length between the motor body of the electric motor and the gear housing. In addition to the effect of the invention of claim 1, since the mounting length of the electric motor protruding from the gear housing is not so large even when the mass of the electric motor is large (when the axial length of the motor body is long), An electric motor having a large mass can be attached to the housing.

  Hereinafter, an electric power steering apparatus according to the present invention will be described with reference to the drawings. 1 is a perspective view showing a schematic configuration of an electric power steering device according to a first embodiment of the present invention, FIG. 2 is a front view of the electric power steering device shown in FIG. 1, and FIG. 3 is an electric power steering shown in FIG. 4 is a plan view of the electric power steering apparatus shown in FIG. 3, FIG. 5 is an exploded perspective view showing a part of the electric power steering apparatus according to the first embodiment, and FIG. 5 is a cross-sectional view showing the inside of the gear housing shown in FIG. 5. FIG. 7 is a view showing the main part of the electric power steering apparatus according to the first embodiment. As shown in FIG. 1, the electric motor according to the first embodiment is shown. The power steering apparatus includes a steering shaft 1, a steering column 2, a gear housing 3, a tilt mechanism 4, a release capsule 5, an electric motor 9, a motor control unit 11, and the like.

The steering shaft 1 includes an input shaft 1a having an upper end connected to a steering wheel (not shown), and an output shaft 1b (see FIG. 3) connected to the lower end of the input shaft 1a via a torsion bar (not shown). Thus, a steering column 2 having a double pipe structure including an inner pipe 2a and an outer pipe 2b is provided on the outer periphery of the input shaft 1a and the output shaft 1b.
The inner tube 2a of the steering column 2 has a gear housing mounting flange 2c at the lower end, and the gear housing 3 is mounted on the gear housing mounting flange 2c.

The gear housing 3 has a connecting portion 3a extending in the axial direction of the steering column 2 at the lower end, and is fixed to a vehicle body side member (not shown) by a bracket mounting plate 6 to the connecting portion 3a. A column support bracket 7 is connected via a pivot 8.
The outer tube 2b of the steering column 2 is provided so as to be coaxial with the inner tube 2a and movable in the axial direction of the inner tube 2a. The outer tube 2b is operated to tilt the steering column 2 about the pivot shaft 8. The tilt mechanism 4 is provided.

  The tilt mechanism 4 includes a U-shaped movable side bracket 4a fixed to the outer peripheral surface of the outer tube of the steering column 2 by spot welding or the like, and a U-shaped fixed side connected to the movable side bracket 4a via a pivot 4b. A tilt lever 4d is attached to the pivot 4b. The tilt mechanism 4 has a bracket mounting plate 4e fixed to the fixed bracket 4c by spot welding or the like, and a pair of left and right release capsules 5 are provided on the bracket mounting plate 4.

  The release capsules 5 are formed by die-casting aluminum, and the release capsules 5 are provided with capsule attachment holes 5a for attaching the release capsules 5 to a vehicle body side member (not shown) with a mounting bolt (not shown). (See FIG. 1). The release capsule 5 has three resin injection holes 5b (see FIG. 1) communicating with resin injection holes (not shown) formed in the bracket mounting plate 4, and injected into these resin injection holes 5b. The release capsule 5 is fixed to the bracket mounting plate 4 by the resin thus formed. Therefore, when the impact force at the time of the secondary collision acts on the outer tube 2b of the steering column 2, the resin injected into the resin injection hole 5b of the release capsule 5 is broken by receiving a shearing force, and the outer tube 2b of the steering column 2 is broken. Moves to the inner tube 2a side.

  The gear housing 3 also has a motor mounting flange 3b (see FIG. 5), and the motor mounting flange 3b has an electric motor 9 as a steering assisting force generating source in the axial direction of the steering column 2. It is attached at a right angle. The gear housing 3 has a control unit mounting surface 3c in the vicinity of the motor mounting flange 3b, and a motor control unit 11 for controlling the electric motor 9 is mounted on the control unit mounting surface 3c. Further, the gear housing 3 is formed by die-casting a metal material having high thermal conductivity (for example, aluminum, aluminum alloy, magnesium, magnesium alloy, etc.). A worm gear mechanism 10 (see FIG. 6) is provided that decelerates and transmits the generated rotational torque to the output shaft 1b of the steering shaft 1. The gear housing 3 has a spigot fitting portion 3d (see FIG. 6), and the motor main body 9a of the electric motor 9 is fitted to the spigot fitting portion 3d.

  The electric motor 9 has a motor output shaft 9b protruding from the motor main body 9a, and a spline hole 12 (see FIG. 6) is formed in the front end surface of the motor output shaft 9b. The electric motor 9 has two connection terminals 9c (see FIG. 5) in the vicinity of the motor mounting flange 3b of the gear housing 3. These motor side connection terminals 9c are made of a metal plate such as a copper plate, and have an L-shape in which a tip end portion is bent toward the gear housing side.

The worm gear mechanism 10 includes a worm shaft 10a and a worm wheel (not shown) that meshes with the worm 10b formed on the worm shaft 10a. The worm shaft 10a is fitted into the above-described spline hole 12 at the motor side end. The spline shaft 13 to be joined is formed integrally with the worm shaft 10a.
As shown in FIG. 5, the motor control unit 11 has two connection terminals 11 a formed in a flat plate shape in the vicinity of the motor mounting flange 3 b of the gear housing 3. These control unit side connection terminals 11a protrude to the electric motor side, and are in surface contact with the motor side connection terminal 9c in a plane parallel to the motor output shaft 9b of the electric motor 9, as shown in FIG. .

  Here, as shown in FIG. 6, the length of the portion where the motor side connection terminal 9c and the control unit side connection terminal 11a overlap (hereinafter referred to as “wrap length”) is L1, the motor output shaft 9b of the electric motor 9 and the worm gear. When the spline fitting length between the worm shaft 10a of the mechanism 10 is L2 and the spigot fitting length between the motor body 9a of the electric motor 9 and the gear housing 3 is L3, in this embodiment, L2> L3> L1. Yes.

7, the distance from the housing side end surface of the motor flange 9d formed on the electric motor 9 to the tip of the motor side connection terminal 9c is L4, and the motor of the motor mounting flange 3b formed on the gear housing 3 is used. The distance from the side end surface to the motor side end surface of the worm shaft 10a is L5, the distance from the motor side end surface of the motor mounting flange 3b to the tip of the control unit side connection terminal 11a is L6, and the motor output shaft from the housing side end surface of the motor flange 9d The distance to the tip of 9b is L7, and the clearance between the motor side connection terminal 9c and the control unit side connection terminal 11a immediately before the motor output shaft 9b of the electric motor 9 is fitted to the worm shaft 10a of the worm gear mechanism 10 is L8 ( In this embodiment, (L4 + L5 + L6) <L7, (L4 + L5 + L6 + L8) = And has a 7.
When the tip of the control unit side connection terminal 11a does not protrude from the motor mounting flange 3b of the gear housing 3 to the electric motor side, the distance L6 is a negative value. Further, when the tip of the motor side connection terminal 9c does not protrude from the motor flange 9d of the electric motor 9 to the gear housing side, the distance L4 is a negative value.

  FIG. 8 shows a state immediately before the motor output shaft 9b of the electric motor 9 is spline-fitted to the worm shaft 10a of the worm gear mechanism 10 in such a configuration. As shown in the figure, immediately before the motor output shaft 9b of the electric motor 9 is spline-fitted to the worm shaft 10a of the worm gear mechanism 10, the motor side connection terminal 9c has not yet wrapped with the control unit side connection terminal 11a. I understand that. This is because the distance L4 from the housing side end surface of the motor flange 9d to the tip of the motor side connection terminal 9c, the distance L5 from the motor side end surface of the motor mounting flange 3b to the motor side end surface of the worm shaft 10a, and the motor of the motor mounting flange 3b. This is because the sum (L4 + L5 + L6) of the distance L6 from the side end surface to the tip of the control unit side connection terminal 11a is smaller than the distance L7 from the housing side end surface of the motor flange 9d to the tip surface of the motor output shaft 9b.

  Therefore, in the first embodiment described above, the distance L4 from the housing side end face of the motor flange 9d to the tip of the motor side connection terminal 9c, and the distance from the motor side end face of the motor mounting flange 3b to the motor side end face of the worm shaft 10a. L5, the sum (L4 + L5 + L6) of the distance L6 from the motor side end surface of the motor mounting flange 3b to the tip of the control unit side connection terminal 11a is calculated from the distance L7 from the housing side end surface of the motor flange 9d to the tip surface of the motor output shaft 9b. When the electric motor 9 is attached to the gear housing 3, the motor side connection terminal 9c is connected to the control unit side before the motor output shaft 9b of the electric motor 9 is spline-fitted with the worm shaft 10a of the worm gear mechanism 10. Since it does not overlap the terminal 11a and come into surface contact, the electric motor The phase alignment between the worm shaft 10a of the motor output shaft 9b and the worm gear mechanism 10 can be easily performed.

  Further, the motor output shaft 9b of the electric motor 9 is spline-fitted with the worm shaft 10a of the worm gear mechanism 10 before the connection terminal 9c of the electric motor 9 wraps with the connection terminal 11a of the motor control unit 11, so that the electric motor 9 Does not move in a direction other than the axial direction and the circumferential direction, so that the electrical connection portion 14 (see FIG. 1) between the electric motor 9 and the motor control unit 11 is brought into contact with the extra portion and the electrical connection portion. 14 can be prevented from being damaged or deformed.

In the first embodiment described above, the motor output shaft 9b of the electric motor 9 is spline-fitted with the worm shaft 10a of the worm gear mechanism 10, but the present invention is not limited to this. For example, the electric motor 9 The present invention can be applied even when the motor output shaft 9b is fitted to the worm shaft 10a of the worm gear mechanism 10 by a coupling or the like.
In the first embodiment described above, the spline fitting length L2 between the motor output shaft 9b of the electric motor 9 and the worm shaft 10a of the worm gear mechanism 10 is such that the spigot fitting between the motor body 9a of the electric motor 9 and the gear housing 3 is performed. Although an example having a length larger than the total length L3 is illustrated, the spline fitting length L2 between the motor output shaft 9b of the electric motor 9 and the worm shaft 10a of the worm gear mechanism 10 is set as an inlay fitting between the motor body 9a of the electric motor 9 and the gear housing 3. The total length L3 may be smaller than L3>L2> L1, so that even when the mass of the electric motor 9 is large (when the axial length of the motor body is long), the electric motor 9 protruding from the gear housing 3 is used. Therefore, the electric motor having a large mass can be attached to the gear housing 3.

1 is a perspective view showing a schematic configuration of an electric power steering apparatus according to a first embodiment of the present invention. It is a front view of the electric power steering apparatus shown in FIG. FIG. 3 is a right side view of the electric power steering device shown in FIG. 2. 4 is a plan view of the electric power steering apparatus shown in FIG. 1 is an exploded perspective view showing a part of an electric power steering apparatus according to a first embodiment of the present invention. It is sectional drawing which shows the inside of the gear housing shown in FIG. It is a figure which shows the principal part of the electric power steering apparatus which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the effect | action of the electric power steering apparatus which concerns on the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering shaft 2 Steering column 2a Inner pipe 2b Outer pipe 2c Gear housing mounting flange 3 Gear housing 3a Connecting part 3b Motor mounting flange 3c Control unit mounting surface 3d Inlay fitting part 4 Tilt mechanism 5 Release capsule 5a Capsule mounting hole 5b Resin injection Hole 6 Bracket mounting plate 7 Column support bracket 8 Pivot 9 Electric motor 9a Motor body 9b Output shaft 9c Connection terminal 9d Motor flange 10 Worm gear mechanism 10a Worm shaft 10b Worm 11 Motor control unit 11a Connection terminal 12 Spline hole 13 Spline shaft 14 Electrical Connection

Claims (2)

An electric motor, a worm gear mechanism that transmits the rotational torque generated by the electric motor to the steering shaft at a reduced speed, a gear housing that houses the worm gear mechanism, and a motor control unit attached to the gear housing, An electric power steering device in which a motor side connection terminal of an electric motor and a control unit side connection terminal of the motor control unit are in contact with each other in the vicinity of a motor mounting flange formed on the gear housing,
The distance from the housing side end face of the motor flange formed on the electric motor to the tip of the motor side connection terminal is L4, and the motor of the worm shaft of the worm gear mechanism from the motor side end face of the motor mounting flange formed on the gear housing. L5 is the distance to the side end face, L6 is the distance from the motor side end face of the motor mounting flange to the front end of the control unit side connection terminal, and the distance from the housing side end face of the motor flange to the front end face of the output shaft of the electric motor. An electric power steering apparatus characterized in that (L4 + L5 + L6) <L7 when the distance is L7.   2. The electric power steering apparatus according to claim 1, wherein a fitting length between the output shaft of the electric motor and a worm shaft of the worm gear mechanism is smaller than an inlay fitting length between the motor body of the electric motor and the gear housing. An electric power steering device.

Images