JP2000211533A - Electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering device which prevents an electric assist mechanism from being interfered with another device at the time of a telescopic operation. SOLUTION: A steering column 1 has an inner column 31 made of a steel pipe disposed on a side of a steering wheel, and an outer column 33 extending backward from a reducing gear box 15. Also, a steering upper shaft 11 has an outer shaft 35 on a side of the steering wheel, and an inner shaft 37 on a side of the reducing gear box 15. The inner column 31 is slidably fitted in the outer column 33, whereas the outer shaft 35 is fitted around the inner shaft 37 through serrations slidably only in the axial direction, which provides a telescopic portion 39 of a telescopic mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering device, and more particularly to a technique for preventing interference between an electric assist mechanism and other devices during a telescopic operation.

[0002]

2. Description of the Related Art In a steering system for an automobile, a so-called power steering device for performing steering assist using an external power source is widely used. Conventionally, a vane type hydraulic pump is generally used as a power source for a power steering device, and many hydraulic pumps are driven by an engine. However, this type of power steering apparatus has a large engine drive loss caused by constantly driving the hydraulic pump (about several horsepower to ten horsepower at the time of maximum load), and is therefore adopted for a light vehicle with a small displacement. It was difficult, and it was inevitable that the fuel consumption of a vehicle with a relatively large displacement could not be ignored. To solve these problems, an electric power steering apparatus (hereinafter, referred to as EPS) using an electric motor as a power source has recently attracted attention. In the EPS, there is no direct engine drive loss because the on-board battery is used as the power source of the electric motor, and the electric motor is started only at the time of steering assist, so that the running fuel consumption is reduced (the engine drive loss related to the alternator). In addition to this, the electronic control can be performed very easily. The EPS is classified into a column-assist type, a rack-assist type, and the like according to a mounting portion of the electric motor. At present, the column-assist type, which is excellent in manufacturing cost and installation space, is mainly used.

[0003] On the other hand, since a steering device of an automobile is used (steered) by an unspecified number of drivers, it is desirable that the position of the steering wheel can be adjusted according to the physique and driving posture of the individual. In order to respond to such demands, not only passenger cars but also freight cars and the like often employ a tilt mechanism or a telescopic mechanism. The tilt mechanism is a mechanism for vertically adjusting the position of the steering wheel, and includes a tilt pivot for swingably supporting the steering column, a tilt lever for fixing the steering column at a desired position (swing angle), and the like. Consists of In addition, the telescopic mechanism
This is a mechanism for adjusting the position of the steering wheel in the front-rear direction (axial direction of the steering shaft). It consists of a telescopic lever for fixing the shaft.

[0004]

In a conventional hydraulic power steering apparatus, the following method has been adopted to establish a tilt mechanism and a telescopic mechanism.
For example, JP-A-5-262239 and JP-A-6-4
In the steering device described in Japanese Patent No. 0342 and the like,
The tilt mechanism and the telescopic mechanism are formed at the same position, and the tilt operation and the telescopic operation can be performed by unlocking a single lever.
However, when such a method is employed in the column assist type electric power steering apparatus, the electric assist mechanism mounted on the steering column moves largely in the axial direction during the telescopic operation. Therefore, it is necessary to provide a large space near the instrument panel with a high device density in order to secure a moving space for the electric assist mechanism, and there is a problem that the degree of freedom in designing other devices is reduced.

In the steering apparatus described in Japanese Utility Model Laid-Open Publication No. 6-78155, a tilt mechanism of a swing-tilt type is provided above the telescopic mechanism, and the tilt operation and the telescopic operation are performed by the tilt lever and the telescopic lever. I try to do each. However, when such a method is employed in the column assist type electric power steering apparatus, the electric assist mechanism is interposed in addition to the above-described problem caused by the axial movement of the electric assist mechanism during the telescopic operation. In addition to this, there has been a problem that the total length of the steering device becomes extremely long and it becomes difficult to mount the steering device on a vehicle. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric power steering device that prevents interference between an electric assist mechanism and another device during a telescopic operation.

[0006]

In order to solve the above problems, according to the first aspect of the present invention, there is provided a steering shaft having a steering wheel mounted on an upper end thereof, a steering column rotatably supporting the steering shaft, An electric assist mechanism attached to the steering column and used for assisting the steering force of the steering wheel, and dividing the steering shaft and the steering column into an upper portion and a lower portion,
An electric power steering apparatus comprising: a tilt pivot serving as a swing fulcrum of the upper portion; and an expansion / contraction portion formed on an upper portion of the steering shaft and used for expansion / contraction of an upper portion of the steering shaft. A device provided above the electric assist mechanism is proposed. In the present invention, since the telescopic portion is provided above the electric assist mechanism, interference between the electric assist mechanism and peripheral devices during telescopic operation does not occur.

According to a second aspect of the present invention, in the electric power steering apparatus according to the first aspect, the tilt operation using the tilt pivot as a swing fulcrum by unlocking a single lock lever; We propose a telescopic operation that expands and contracts the part at the same time. In the present invention, the tilt operation and the telescopic operation can be performed with one lock lever, and the overall length of the steering device is relatively short.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a passenger compartment side portion of an electric power steering apparatus according to a first embodiment of the present invention, and reference numeral 1 in the figure denotes a steering column. The steering column 1 has a tilt bracket 3
And the pivot pin 5, it is fixed to cross members 7, 9 which are body structural members. Steering column 1
A steering upper shaft 11 is rotatably supported therein, and an electric assist mechanism 19 including an electric motor 13, a reduction gear box 15, an output shaft 17 and the like is integrated at a distal end portion. In the case of the present embodiment, the reduction gear box 15 is a cast product made of an aluminum alloy, and the pivot pin 5 is rotatably inserted in a pivot bracket 21 fixed to a front end surface thereof. In FIG. 1, reference numeral 23 denotes a steering intershaft, which is connected to the tip of the output shaft 17 via a universal joint 25.

A steering wheel 27 is attached to the rear end of the steering upper shaft 11. When the driver turns the steering wheel 27, the rotational force is increased by the electric assist mechanism 19 and the output shaft 17 is rotated. And transmitted to a steering gear at the lower part of the vehicle body via a steering lower shaft (not shown).

In the first embodiment, as shown in FIG.
The steering column 1 includes an inner column 31 made of a steel pipe located on the steering wheel 27 side, and an outer column 33 extending rearward from the reduction gear box 15. Also, the steering upper shaft 11
Is the outer shaft 35 on the steering wheel 27 side.
And an inner shaft 37 on the reduction gear box 15 side. In the case of the first embodiment, the inner column 31
Are slidably fitted inside the outer column 33, while the outer shaft 35 is
7 is slidably fitted only in the axial direction, thereby forming a telescopic part 39 of the telescopic mechanism. In FIG.
The members indicated by reference numerals 41 and 43 are rolling bearings interposed between the inner column 31 and the outer shaft 35.

FIGS. 2 and 3 (enlarged sectional view taken along line AA in FIG. 2)
As shown in (1), a pair of right and left lock blocks 51 having a substantially cylindrical shape are held at the lower rear end of the outer column 33.
Each of the lock blocks 51 has an inclined surface 53 facing the outer peripheral surface of the inner column 31 inside thereof, and its outer end surface protrudes from the side surface of the outer column 33 by a predetermined amount. Further, a through hole 54 is provided in the axis of the lock block 51.
On the other hand, the tilt bracket 3 is formed with an arc-shaped long hole 55 centered on the pivot pin 5.
A lock bolt 57 is inserted into the through hole 54 and the elongated hole 55. The lock bolt 57 is screwed into a nut 61 integrated with the lock lever 59. In the figure, reference numeral 6
The member indicated by 3 is a bolt for fastening the lock lever 59 and the nut 61.

The operation of the first embodiment will be described below. In the case where the position of the steering wheel 27 becomes inappropriate due to a change of the driver or the like, in the electric power steering apparatus according to the first embodiment, the driver first turns the lock lever 59 to the unlock side, and the lock bolt 57 The nut 61 is loosened. Then, the axial force of the lock bolt 57 acting on the tilt bracket 3 and the lock block 51 disappears, so that the steering column 1 can swing about the pivot pin 5 by a predetermined amount, and at the same time, the inner column 31 and the outer shaft 35 are rotated. Can slide with respect to the outer column 33 and the inner shaft 37 by a predetermined amount. Thereby, the driver can tilt or telescopically operate the steering column 1 to adjust the steering wheel 27 to a desired position.

At this time, the telescopic part 39 of the telescopic mechanism is used.
Is provided above the electric assist mechanism 19,
The electric assist mechanism 19 does not move due to the telescopic operation. In addition, since the electric assist mechanism 19 is located immediately above the pivot pin 5, the amount of movement of the electric assist mechanism 19 due to the tilt operation is suppressed to a very small value. Therefore, unlike the above-described conventional device, it is not necessary to secure a large moving space for the electric assist mechanism 19 near the steering column 1, and the degree of freedom in designing the device near the instrument panel can be increased.

When the position adjustment of the steering wheel 27 is completed, the driver turns the lock lever 59 to the lock side in the opposite direction from the front, and
Tighten 1. Then, the tilt bracket 3 is elastically deformed by being pressed by the lock bolt 57 and the nut 61, and the lock block 51 is pushed inward. Thereby, the lock block 5 is provided on the inner surface of the tilt bracket 3.
The outer end surface of the inner block 31 is pressed against the outer peripheral surface of the inner column 31, while the outer end surface of the inner block 31 is pressed against the outer surface. As a result, the steering column 1 is fixed in the tilt direction by the frictional force between the tilt bracket 3 and the lock block 51, and is also fixed in the telescopic direction by the frictional force between the lock block 51 and the inner column 31. You.

As described above, in the first embodiment, the tilt operation and the telescopic operation can be performed simultaneously by operating the single lock lever 59, so that the position adjustment of the steering wheel 27 becomes extremely easy and the steering column 1 was also able to be shortened.

FIG. 4 shows a longitudinal section of a main part of a steering column 1 according to a second embodiment of the present invention. The second embodiment is different from the above-described first embodiment only in the fitting portion between the inner column 31 and the outer column 33, and the other configuration and operation are the same. Omitted.

As shown in FIG. 4, in the second embodiment, a sleeve 71 made of steel pipe is externally fitted and fixed (welded) to the outer peripheral end of the inner column 31, so that the outer column 33 and the sleeve 71 are joined together. Is configured to slide. Thus, the support rigidity of the inner column 31 by the outer column 33 is improved, and the possibility that the inner column 31 is deformed even when the driver puts weight on the steering wheel 27 is reduced. The sleeve 71
An annular groove 73 is formed on the inner peripheral surface at a position corresponding to the rolling bearing 43 so that unnecessary pressing force or the like does not act on the rolling bearing 43.

The description of the specific embodiment has been completed.
The aspects of the present invention are not limited to the above embodiment.
For example, in each of the above-described embodiments, the locking of the steering column in the tilt direction and the telescopic direction is performed using the lock block. However, various known fixing methods can be employed. In addition, the specific configuration of the tilt mechanism and the telescopic mechanism, including the electric assist mechanism, can be appropriately changed without departing from the gist of the present invention.

[0019]

As described above, according to the electric power steering apparatus of the present invention, the steering shaft on which the steering wheel is mounted on the upper end, the steering column that rotatably supports the steering shaft, An electric assist mechanism attached to the steering column and used for assisting the steering force of the steering wheel; dividing the steering shaft and the steering column into an upper part and a lower part; An electric power steering apparatus comprising: a tilt pivot; and a telescopic part formed on an upper part of the steering shaft and used for expanding and contracting the upper part of the steering shaft, wherein the telescopic part is provided above the electric assist mechanism. I did it for Teres Interference between the electrical power assisting mechanism and the peripheral device no longer occurs during operation, it is not necessary to ensure a large moving space of the electric assist mechanism in the vicinity of the steering column.

Further, by operating a single lock lever to unlock, a tilt operation using the tilt pivot as a swing fulcrum and a telescopic operation for expanding and contracting the extendable portion can be simultaneously performed. Since the tilt operation and telescopic operation can be performed with a single lock lever, it is easy to adjust the position of the steering wheel when the driver changes, etc., and the overall length of the steering device is relatively short. The degree of freedom is increased, and installation on a car becomes easy.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the structure of a steering device according to the present invention on the passenger compartment side.

FIG. 2 is a sectional side view of a main part of the steering column according to the first embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along line AA in FIG. 2;

FIG. 4 is a longitudinal sectional view of a main part of a steering column according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Steering Column 3 Tilt Bracket 5 Pivot Pin 11 Steering Upper Shaft 27 Steering Wheel 31 Inner Column 33 Outer Column 35 Outer Shaft 37 Inner Shaft 51 Lock Block 57 ‥‥ Lock bolt 59 ‥‥ Lock lever 61 ‥‥ Nut 71 ‥‥ Sleeve

Claims (2)

[Claims] 1. A steering shaft having a steering wheel mounted on an upper end thereof, a steering column rotatably supporting the steering shaft, and a steering column mounted on the steering column to assist in steering force of the steering wheel. An electric assist mechanism; a tilt pivot that divides the steering shaft and the steering column into an upper portion and a lower portion, and serves as a swing fulcrum of the upper portion; and a steering shaft that is formed in an upper portion of the steering shaft. An electric power steering apparatus comprising: a telescopic part provided for expanding and contracting an upper part of the electric power steering apparatus, wherein the telescopic part is provided above the electric assist mechanism. 2. A tilt operation using the tilt pivot as a swing fulcrum and a telescopic operation for expanding / contracting the expansion / contraction portion can be simultaneously performed by unlocking a single lock lever. The electric power steering device according to claim 1.