JPH058739A - Electric power steering equipement - Google Patents

Abstract

PURPOSE:To miniaturize a whole equipment and to improve the operation feeling, by applying the means to constitute an armature and so on, which a printed coil plate arranged between a pair of toroidal permanent magnets, and with a rotor shaft arranged coaxially around a steering shaft. CONSTITUTION:An equipment main body is constituted by assembling right and left electric motor unit A and reduction gear unit B coaxially, to a steering shaft 11 and a steering column 12 which rotatably supports the steering shaft 11. The electricity is applied to a printed coil plate 26 through a brush 28 with steering operation, and an armature consisting of this and a rotor shaft is rotated. Thereafter, torque is transmitted to the steering shaft 11 through a epicycle reduction gear 31-36 and a sleeve 13. In this case, the armature is constituted compactly as a whole, by the printed coil plate 26 set between a pair of toroidal permanent magnets 23, and by the rotor shaft 25 set around the steering shaft 11.

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 system in a vehicle, in which torque generated by an electric motor is transmitted to a steering shaft.

[0002]

2. Description of the Related Art An electric power steering apparatus is generally called an electric power steering apparatus in which a torque generated by an electric motor acts to assist an operating force (for example, Japanese Patent Laid-Open No. Sho 58-141963). (See the official gazette) and an electric reaction type power steering device in which the torque generated by the electric motor acts as a reaction force.

[0003]

By the way, in any of the above-mentioned types, the electric power steering device is required to be small in size for mounting on a vehicle, and
In terms of operation feeling, it is necessary to reduce the moment of inertia acting on the steering shaft. In the power steering device proposed in Japanese Patent Application Laid-Open No. 58-141963, an electric motor is arranged coaxially with the steering shaft, but since the iron core of the electric motor is attached to the steering shaft, Not only is the miniaturization not sufficient, but the moment of inertia acting on the steering shaft is large, and there is room for improvement in terms of operation feeling. The present invention has been made in view of the above situation, and an object thereof is to reduce the size of the electric power steering device and improve the operation feeling.

[0004]

In order to achieve the above object, according to the present invention, a housing for coaxially assembling the electric power steering device to a steering column rotatably supporting a steering shaft is provided. A pair of annular permanent magnets that are assembled to the housing so as to face each other, and a cylindrical rotor shaft that is rotatably assembled to the shaft center portion of the housing and is coaxially arranged on the outer periphery of the steering shaft. A print coil plate integrally mounted on the rotor shaft and disposed between the permanent magnets, and a sun gear integrally formed on the outer periphery of the rotor shaft as an input element and rotatably mounted on the housing. Assembled to engage with the sleeve mounted on the steering shaft so as to be able to rotate integrally And configured to include a planetary gear reduction mechanism that the carrier and the output element.

[0005]

In the electric power steering apparatus according to the present invention, when the printed coil plate is energized, the armature composed of the printed coil plate and the rotor shaft rotates and the steering is performed via the planetary gear speed reduction mechanism and the sleeve. Torque is transmitted to the shaft. By the way, in the present invention, the armature is made compact by the print coil plate arranged between the pair of annular permanent magnets and the rotor shaft coaxially arranged on the outer periphery of the steering shaft. Since a printed coil plate is arranged between the annular permanent magnets in order to obtain the required amount of magnetic flux in a flat and small shape, the sun gear, which is the input element of the planetary gear reduction mechanism, is further used in the rotor shaft that constitutes the armature. Since it is integrally formed on the outer circumference, the electric power steering device can be downsized. Further, in the present invention, since the armature is composed of the printed coil plate and the rotor shaft and does not include the iron core having a large mass, the moment of inertia acting on the steering shaft can be reduced and the operation feeling can be improved. Can be improved.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. The electric power steering apparatus according to the present invention shown in FIG. 1 is coaxially assembled to a steering shaft 11 and a steering column 12 that rotatably supports the steering shaft 11 shown in phantom lines, and is shown on the left side of the drawing. The electric motor unit A and the speed reducer unit B on the right side of the drawing are included.

The electric motor section A is a pair of annular permanent magnets (rare earth magnets) assembled to the housings 21A and 21B (non-magnetic material) fitted and fixed to the end of the steering column 12 so as to face each other via the yoke 22. Is preferable, and other types of magnets may be used) 23 and the housings 21A, 2 by being attached to the yoke 22 via the bearing 24.
The cylindrical rotor shaft 25 is rotatably assembled to the shaft center portion of 1B and is coaxially arranged on the outer periphery of the steering shaft 11, and is integrally assembled to the left end portion of the rotor shaft 25 in the drawing. A print coil plate 26 disposed between both permanent magnets 23, a brush 28 attached to a brush holder 27 attached to the yoke 22 to energize the print coil plate 26, and the brush 28 attached to the print coil plate 26. Spring 29 that urges toward
It is composed by.

On the other hand, the speed reducer section B has a rotor shaft 25.
And a sun gear 31 integrally formed on the outer periphery of the right end of the figure,
A ring gear 32 integrally formed on the inner periphery of the right end portion of the yoke 22 in the figure, a planetary gear 33 that constantly meshes with both gears 31, 32, and a planetary gear 33 rotatably supported via a bearing 34 and a bearing 35.
The sleeve 1 is rotatably supported by the housing 21A through the teeth and is integrally rotatably mounted on the steering shaft 11 by a tooth portion 36a integrally formed on the inner circumference of the right end in the figure.
Carrier 36 engaged with the tooth portion 13a of No. 3 so as to be able to transmit power.
Is a planetary gear reduction mechanism that uses the sun gear 31 as an input element and the carrier 36 as an output element. A bearing 37 is interposed between the sun gear 31 and the carrier 36. In addition, steering column 1
A bearing 14 is interposed between the sleeve 2 and the sleeve 13.

In this embodiment constructed as described above, when the print coil plate 26 is energized from the controller (not shown) through the brush 28 in response to the steering operation, the print coil plate 26 and the rotor shaft 25 are formed. The armature rotates and the sun gear 3
Torque is transmitted to the steering shaft 11 via the planetary gear speed reduction mechanism including the ring gear 32, the planetary gear 33, the carrier 36 and the like, and the sleeve 13.

By the way, in the present embodiment, the armature is constituted by the print coil plate 26 disposed between the pair of annular permanent magnets 23 and the rotor shaft 25 coaxially disposed on the outer periphery of the steering shaft 11. And a compact structure, a pair of annular permanent magnets 23
Since the printed coil plate 26 is disposed between the rotor and the outer circumference of the rotor shaft 25 which constitutes the armature, the sun gear 31 which is an input element of the planetary gear speed reduction mechanism is further provided because the required amount of magnetic flux is obtained in a flat and small shape. Since the ring gear 32 is integrally formed on the inner circumference of the yoke 22, the electric power steering device can be downsized.

Further, in the present embodiment, the armature is composed of the printed coil plate 26 and the rotor shaft 25 and does not have an iron core having a large mass. Therefore, the moment of inertia acting on the steering shaft 11 should be reduced. The operation feeling can be improved. Such an effect can be more clearly obtained by forming the sleeve 13, the carrier 36, the planetary gear 33, and the like with a lightweight material (for example, a sintered material or a resin material).

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

[Explanation of symbols]

11 ... Steering shaft, 12 ... Steering column, 13 ... Sleeve, 21A, 21B ... Housing, 2
3 ... A pair of annular permanent magnets, 25 ... Cylindrical rotor shaft, 26 ... Print coil plate, 31 ... Sun gear,
32 ... Ring gear, 33 ... Planetary gear, 36 ... Carrier, A ... Electric motor part, B ... Reduction gear part (planetary gear reduction mechanism).

Claims (1)

Claim: What is claimed is: 1. A housing that is coaxially assembled to a steering column that rotatably supports a steering shaft, a pair of annular permanent magnets that are assembled to the housing so as to face each other, and the housing. A cylindrical rotor shaft that is rotatably mounted on the shaft center of the steering shaft and is coaxially arranged on the outer periphery of the steering shaft, and is integrally mounted on the rotor shaft and disposed between the permanent magnets. And a printed coil plate, and a sun gear integrally formed on the outer periphery of the rotor shaft as an input element, rotatably assembled to the housing, and power transmission to a sleeve integrally rotatably assembled on the steering shaft. Electric power stearin comprising a planetary gear reduction mechanism with a carrier that is engagable as an output element Apparatus.