JPH06227409A - Steering device for automobile - Google Patents

Abstract

PURPOSE:To provide a steering device for an automobile which gives a non- linear characteristic by integrally forming a pinion and one of noncircular gear, supporting the shaft of a gear member in the direction intersecting rectilinearly to the axis, and pressing at least one of a rack, the shaft of the other of noncircular gears and the connecting shaft of the gear member. CONSTITUTION:A first elliptic gear 12 is rotatably supported on an input shaft 11, and a second elliptic gear 16 is meshed with the first gear. A shaft part 17 and a helical gear 18 are integrally formed, and the shaft part 17 is supported on a gear case 15 in such a manner as to be freely rotated and oscillated. A self-aligning bearing 19 is loosely fitted in an elongated groove 20, a spring guide 21 is pressed to the bearing in such a manner that the distance between the elliptic gears 12,16 is adjusted and pressed toward the outer ring of the self-aligning bearing 19 by a coiled spring 22. The helical gear 18 is meshed with a rack gear 23 and supported on the gear case 15 in such a manner as to freely slide rectilinearly. In so constructed noncircular gears, the relation of rotating angles of a steering wheel 1 and a pinion 4 has a non-linear characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a steering system for a vehicle having a rack and pinion mechanism, and more particularly, a ratio of a steering angle of a steering wheel to a steering angle of a steering wheel, that is, a steering angle ratio is nonlinear. The present invention relates to a steering device having characteristics.

[0002]

2. Description of the Related Art Recently, as a vehicle steering system, a system using a rack and pinion mechanism as shown in FIG. As is well known, this is for the steering shaft 2 integrally connected to the steering wheel 1,
The rotational movement of the pinion 4 directly connected via the connecting shaft 3 having a universal joint is converted into the linear movement of the rack 5 meshed with the pinion 4, and the linear movement of the rack 5 is passed through the tie rod 6 and the knuckle arm 7. It is adapted to be converted into a steering movement of the wheels 8.

On the other hand, the conventional type steering device has a linear steering angle characteristic in which the steering angle of the wheel changes substantially linearly with respect to the rotation angle of the steering wheel. 1.5 from the neutral position to the left and right
It is set so that the maximum steering angle is given to the wheels by the degree of rotation (see the thin line (A) in FIG. 9). Here, considering only the maneuverability of the vehicle, it is preferable that the number of rotations of the steering wheel for obtaining the maximum steering angle of the wheel is small. However, for example, the steering angle characteristic as shown by the one-dot chain line (B) in FIG. When set to, the amount of steering is reduced, so good maneuverability can be obtained in the low speed range, but on the other hand, consideration should be given not to turn the steering wheel too much in the high speed range because the vehicle behavior becomes extremely sensitive to the steering angle of the steering wheel. Need to do so.

Therefore, it is conceivable to use a steering device in which a gear box for transmitting the rotation of the steering wheel to a steering wheel is provided with a mechanism for giving a non-linear characteristic (see Japanese Utility Model Laid-Open No. 1-161875). As a result, as indicated by a thick line (C) in FIG. 9, the rotation angle of the pinion gear becomes smaller in the region where the steering angle of the steering wheel is small, and the rotation angle of the pinion gear becomes smaller in the region where the steering angle of the steering wheel is large. A larger non-linear characteristic can be realized.

[0005]

However, in order to realize such a non-linear steering angle characteristic, complication of the gear mechanism is unavoidable, and the number of elements causing backlash increases. The inconvenience that the sexual feeling is disturbed occurs.

The present invention has been devised in order to eliminate such disadvantages of the prior art, and its main purpose is to:
For automobiles improved to provide non-linear characteristics so that steering feeling does not change so much during low speed traveling and high speed traveling, and also to eliminate rattling of a plurality of gears by one pressing means To provide a steering device.

[0007]

According to the present invention, there is provided a rack and pinion mechanism for converting a rotation angle of a steering wheel into a steering angle of a steering wheel. The configuration of an automobile steering system in which the output shaft of the rack and pinion mechanism is interlockingly connected via a pair of non-circular gears, the pinion of the rack and pinion mechanism and the non-circular gear of One of them is integrally formed, and the shaft of the integrally formed gear member is supported so as to be displaceable in a direction orthogonal to the axis thereof, and the other shaft of the rack of the rack and pinion mechanism and the non-circular gear is formed. And a pressing means for pressing at least one of the connecting shafts of the gear member.

[0008]

According to this structure, by using a non-circular gear such as an elliptical gear in which the length of the pitch circumference is non-uniform with respect to the angle, rotation of the pinion is achieved in a region where the steering angle of the steering wheel is small. In the region where the angle becomes smaller and the steering angle of the steering wheel becomes larger, the rotation angle of the pinion also becomes larger, so that a non-linear characteristic can be given to the relationship between the rotation angle of the steering wheel and the rack stroke. The backlash can be suppressed by constantly applying the pressing force in the direction in which the meshing gap between the pair of non-circular gears becomes smaller.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows a first embodiment of a steering apparatus constructed according to the present invention. This device is provided in a portion shown by an imaginary line in FIG.

The input shaft 11 connected to the steering wheel 1 is integrally provided with a first elliptical gear 12 at a lower position in FIG. The input shaft 11 and the first elliptical gear 12 are rotatably supported by a gear case 15 via a ball bearing 13 and a needle bearing 14 which are arranged so as to sandwich the first elliptical gear 12.

The first elliptical gear 12 has a second elliptical gear 1
6 is in mesh. A shaft portion 17 and a helical gear 18 as a pinion are integrally formed below the second elliptical gear 16. The shaft portion 17 is rotatably and swingably supported by the gear case 15 via a self-aligning bearing 19.

The self-aligning bearing 19, as shown in FIG.
The gear case 15 is loosely fitted into a long groove 20 formed long in a direction orthogonal to the axis of the shaft portion 17, whereby the axial distance between the first and second elliptical gears 12 and 16 is reduced. It is designed to be adjusted within the range. A spring guide 21 is in contact with the surface of the outer ring of the self-aligning bearing 19 on the side opposite to the input shaft side. The spring guide 21 is pressed by the coil spring 22 toward the outer ring of the self-aligning bearing 19.

The helical gear 18 meshes with rack teeth 23 provided on the rack 5 extending on the same side as the input shaft 11. The rack 5 is linearly slidably supported by the gear case 15 via a rack guide 24. The rack and pinion mechanism is constituted by these.

Due to the pressing force generated by the coil spring 22 described above, the second elliptical gear 16 and the helical gear 18 together with respect to the first elliptic gear 12 and the rack teeth 23, which are the counterparts,
Can be engaged without backlash.

By the way, the pair of elliptical gears 12 and 16 are
As shown in FIG. 3, the focal point of each ellipse is the center of rotation C1, C2.
In addition, in the neutral position of the steering wheel, the major axes of the ellipses are set on a common straight line.

According to the non-circular gear type steering device constructed by using the pair of elliptical gears 12 and 16 as described above, the relationship between the rotation angles of the steering wheel 1 and the pinion 4 is as follows.
With the extremely simple structure, the non-linear characteristic shown by the thick line in FIG. 9 can be obtained. That is, in this device, in a region where the steering angle of the steering wheel is small, the rack stroke is smaller than that of the conventional steering device.
A more insensitive (stable) characteristic can be realized, and in a region where the steering angle is large, the rack stroke becomes larger than that of a conventional steering device, so that a more sensitive (sharp) characteristic can be realized.

As a result, the same effect as that in which the practical turning angle is changed according to the traveling speed is obtained, and the relationship between the traveling speed and the steering wheel rotation angle in the conventional steering device is shown in FIG. Compared with the characteristic indicated by the thin line (D), the characteristic indicated by the thick line (E) is obtained, and the change in the steering feeling due to the speed change is reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The parts corresponding to those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The second elliptical gear 16 of the pair of elliptical gears 12 and 16 in the second embodiment is integrally provided with the helical gear 18 at the lower position of FIG. And a helical gear 18 are integrally formed with a gear member G
Both shaft ends are rotatably supported by the gear case 15 by a ball bearing 25 and a needle bearing 26.

The outer races of the ball bearing 25 and the needle bearing 26 are fitted and supported on the inner circumferences of cylindrical support members 27a and 27b whose outer circumferences are rotatably fitted on the gear case 15. The support members 27a and 27b are shown in FIGS.
As shown in FIG. 5, the center of the outer peripheral portion and the center of the inner peripheral portion are offset (dimension a), and inside the gear case 15, the gear member G is rotated around the center of the outer peripheral portion of the support members 27a and 27b. The rotation of the central shaft allows the gear member G to be displaced by the amount of the offset amount, whereby the axial distance from the input shaft 11 is adjusted. Further, the support members 27a and 27b are provided by a bridge member (not shown).
By interlocking with each other, the central axis of the gear member G can be smoothly rotated.

In the second embodiment, the rack 5 is located on the opposite side of the input shaft 11 with the gear member G interposed therebetween, and the rack 5 is slidably supported on the back surface of the rack 5. The rack guide 24 and the coil spring 22 that presses the rack guide 24 are provided. This pressing force removes the backlash in the meshing of the elliptical gears 12 and 16, the rack teeth 23, and the helical gear 18.

In this embodiment, as compared with the above-described first embodiment, the shaft of the gear member G in which the second elliptical gear 16 and the helical gear 18 are integrally formed is the same as the input shaft 11. Since the gears can be displaced while maintaining the parallel state, the meshing of the gears is further improved, and smooth operation can be obtained.

Although the embodiment using the elliptical gear has been described above, a bilobal ellipse, a trilobal ellipse, a logarithmic spiral gear, or the like may be used instead.

[0024]

As described above, according to the present invention, a desirable steering characteristic capable of simultaneously improving maneuverability during parking, sharp handling at low and medium speeds, and stability at high speed is extremely simple. Can be obtained at. Moreover, despite the meshing of a plurality of gears, it is possible to remove backlash by a simple method and obtain a robust steering feeling without backlash.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the configuration of a first embodiment of the device of the present invention.

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

FIG. 3 is a transverse sectional view taken along the line III-III in FIG.

FIG. 4 is a characteristic comparison diagram of the conventional device and the device of the present invention.

FIG. 5 is a vertical sectional view showing the configuration of a second embodiment of the device of the present invention.

6 is a cross-sectional view taken along the line VI-VI of FIG.

7 is a cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is a schematic overall view of a vehicle steering system to which the present invention is applied.

FIG. 9 is a comparison diagram of various steering characteristics.

[Explanation of Codes] 1 Steering Wheel 2 Steering Shaft 3 Connection Shaft 4 Pinion 5 Rack 6 Tie Rod 7 Knuckle Arm 8 Wheel 11 Input Shaft 12 First Elliptical Gear 13 Ball Bearing 14 Needle Bearing 15 Gear Case 16 Second Elliptical Gear 17 Shaft 18 Helical gear 19 Self-aligning bearing 20 Long groove 21 Spring guide 22 Coil spring 23 Rack tooth 24 Rack guide 25 Ball bearing 26 Needle bearing 27a / 27b Support member

Claims (3)

[Claims] 1. A rack-and-pinion mechanism for converting a rotation angle of a steering wheel into a steered angle of a steered wheel, and a space between an output shaft of the steering wheel and an input shaft of the rack-and-pinion mechanism. A steering apparatus for an automobile, which is interlockingly connected through a pair of non-circular gears, wherein a pinion of the rack and pinion mechanism and one of the non-circular gears are integrally formed and the gear member is integrally formed. A connecting shaft of the rack and pinion mechanism, the other shaft of the non-circular gear, and at least one of the connecting shafts of the gear members. A steering apparatus for an automobile, comprising a pressing means for pressing. 2. The rack of the rack and pinion mechanism is arranged on the same side as the output shaft of the steering wheel with respect to the gear member, and the gear is provided to exert a pressing force toward the other of the non-circular gears. The vehicle steering apparatus according to claim 1, wherein the pressing means is provided on a bearing portion of the member. 3. The rack of the rack and pinion mechanism is arranged on the opposite side of the output shaft of the steering wheel with the gear member interposed therebetween, and the pressing force is applied to the other of the non-circular gears. The vehicle steering system according to claim 1, wherein the pressing means is provided on the side of the rack opposite to the rack gear surface.