JPH0672343A - Steering device - Google Patents

Abstract

PURPOSE:To prevent the working oil of a servo valve from being leaked into a gear housing and being mixed with the lubrication oil of an interlocking mechanism or the like when the housing of a hydraulic-powered steering device is separated. CONSTITUTION:An intermediate rotary member 38 is eccentrically provided between an input shaft 11 where a servo valve 20 of a powered steering device is mounted and an output shaft 13, and the speed of the input shaft 11 is reduced by a speed reducing mechanism 40 consisting of an input pinion 41 and an internal gear 42, and the rotation is transmitted to the intermediate rotary member 38. An oil seal 49 is provided between an internal circumferential surface of a cylindrical bearing cap 19 where a bearing 17b to support the input shaft 11 is pressed against and fixed to a valve housing 10a and a boss member 12 of the input pinion 41, and no working oil of the servo valve 20 leaks into a gear housing 10b when the valve housing 10a is separated from the gear housing 10b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for steering wheels of an automobile, etc., and more particularly to a hydraulic system in which a steering gear ratio (steering wheel rotation angle / tire turning angle) is reduced in accordance with an increase in the steering wheel rotation angle. Type power steering apparatus.

[0002]

2. Description of the Related Art Applicants have previously proposed Japanese Patent Application No. 3-24 as a steering device in which the steering gear ratio is reduced in accordance with an increase in the steering wheel rotation angle and the degree of freedom in designing its characteristics is high.
A steering device according to No. 0398 was proposed. This technology is shown in Figure 4.
As shown in the main part thereof, the input pinion 5a is provided between the input shaft 1 and the intermediate rotating member 2 which are arranged eccentric to each other by a predetermined amount.
A steering mechanism for transmitting rotation from the former to the latter while gradually reducing the steering gear ratio between the intermediate rotating member 2 and the output shaft 3 in accordance with the increase of the rotation angle between the intermediate rotating member 2 and the output shaft 3 is provided. The application mechanism 4 is provided.
In addition, this is a hydraulic power steering apparatus that operates a power cylinder by a servo valve that operates according to the torque applied to the input shaft 1 to apply an assist force to an output operation member (rack bar).

[0003]

In this type of hydraulic power steering apparatus, the operating oil for operating the servo valve and the hydraulic reaction mechanism provided in the valve housing 10a is sealed by the O-ring 8 and therefore decelerated. Although a large amount does not leak to the mechanism 5 side, a small amount of leak is unavoidable, and in the prior art shown in FIG. 4, this is gradually accumulated in the chamber R in which the speed reduction mechanism 5 is located.
This hydraulic oil is usually used for the intermediate rotary member 2 and the valve housing 10.
It is prevented from leaking into the gear housing 10b provided with the steering characteristic imparting mechanism 4 and the rack and pinion mechanism by being blocked by the oil seal 7 provided between a and. However, for maintenance and inspection, the valve housing 10a and the gear housing 10b
When the oil seal 7 is separated, the oil seal 7 is separated on the valve housing 10a side and the intermediate rotary member 2 is separated on the gear housing 10b side, so that the hydraulic oil accumulated in the chamber R leaks into the gear housing 10b and has different characteristics. If it is mixed with the lubricating oil and reassembled as it is, the lubrication of each member in the gear housing 10b may be adversely affected. It is an object of the present invention to solve such a problem by devising an oil seal mounting structure in this type of steering device.

[0004]

To this end, the steering apparatus according to the present invention, as illustrated in FIGS. 1 to 3, has an input shaft 11 connected to a steering handle and rotating together, and an output shaft 1.
3 and an interlocking mechanism 15 connected to the input shaft 11 and an output operating member 14 for steering wheels via a steering link.
And a power cylinder 30 which gives an assisting force to the output operating member, and an assisting force which is provided on the input shaft 11 and operates in accordance with a torque applied thereto to change the assisting force which the power cylinder 30 gives to the output operating member 14. Servo valve 20 and valve housing 1 supporting this servo valve 20
0a, a gear housing 10b that supports the interlocking mechanism 15 and the output shaft 13, and a steering device provided with the housing 10, the input shaft 11 and the output shaft 13 being eccentric with respect to the input shaft. The supported intermediate rotating member 38, the input pinion 41 integrally provided at the end of the input shaft 11 on the intermediate rotating member 38 side, and the input pinion 41 integrally provided at the intermediate rotating member and meshing with the input pinion 41. And a reduction mechanism 40 configured to reduce the rotation of the input shaft and transmit the rotation of the input shaft to the intermediate rotating member, and a liquid-tight insert from the input pinion 41 side to the inner peripheral surface of the valve housing 10a. A cylindrical bearing retainer 19 for pressing and fixing the bearing 17b supporting the input shaft 11 to the valve housing, an inner peripheral surface of the bearing retainer, and an outside of the input pinion 41. Oil seal 4 provided between the surface
It is characterized by having 9.

[0005]

The rotation of the input shaft 11, which rotates with the steering wheel, is reduced by the reduction mechanism 40 including the input pinion 41 and the internal gear 42 and transmitted to the intermediate rotating member 38, and the output shaft 13, the interlocking mechanism 15, and the output operating member. Steer wheels via 14.

When the housing 10 is disassembled for maintenance and inspection, both the bearing retainer 19 and the input pinion 41 are disassembled while assembled on the valve housing 10a side, so that the seal by the oil seal 49 is maintained, and The hydraulic oil leaking from the valve 20 and accumulated in the valve housing 10a is blocked by the oil seal 49 and does not leak to the gear housing 10b side.

[0007]

As described above, according to the present invention, the operating oil of the power steering device in the valve housing does not leak to the gear housing side when the housing is disassembled, so that the lubricating oil in the gear housing is not leaked. There is no risk that foreign oil will be mixed in and will adversely affect the lubrication of each member in the gear housing after reassembly.

[0008]

The present invention will be described below with reference to the embodiments shown in FIGS. As shown in FIG. 1, the housing 10 of the steering apparatus according to the present embodiment is composed of a valve housing 10a and a gear housing 10b that are screwed and fixed to each other. The input shaft 11 and the latter half 11a thereof arranged coaxially with each other are supported in the valve housing 10a via bearings 17a and 17b, and are elastically relatively rotatably coupled by a torsion bar 16.

The outer ring of the bearing 17b that supports the latter half 11a is pressed by a cylindrical bearing retainer 19 that is liquid-tightly screwed into the inner peripheral surface of the valve housing 10a from the input pinion 41 side through an O-ring, It is fixed to the valve housing 10a. Further, at the rear portion of the latter half portion 11a of the input shaft 11, a boss member 12 having an input pinion 41 formed at its tip portion is prevented from rotating by a key 11c, and is fixed to the latter half portion 11a together with an inner ring of a bearing 17b by a nut 11b. There is.

An intermediate portion of the boss member 12 adjacent to the input pinion 41 is supported by a bearing retainer 19 via a bearing 17c, and a bearing retainer 19 is provided between the two bearings 17b, 17c.
An oil seal 49 is provided which is liquid-tightly fitted and supported by the inner peripheral surface of the inner peripheral surface of the boss member 12 and is in liquid-tight contact with the outer peripheral surface of the boss member 12 in a relatively rotatable manner. The fitting surface between the latter half 11a and the boss member 12 is liquid-tightly sealed by an O-ring 11d.

On the rear side of the input shaft 11, an intermediate rotating member 38 is supported eccentrically in parallel with the input shaft 11 in the gear housing 10b via two bearings 18c. The amount of eccentricity between the two is e. The internal gear 4 coaxially formed in the front half of the intermediate rotating member 38
Reference numeral 2 meshes with an input pinion 41 formed on the boss member 12 to reduce the rotation of the input shaft 11 to reduce the rotation of the intermediate rotation member 3.
8 constitutes a reduction mechanism 40.

The output shaft 13 of which the output flange 39 of the steering characteristic imparting mechanism 45, which will be described later, is coaxially fixed to the front end via the key 39a, has the input shaft 1 via the bearings 18a and 18b.
It is supported by the gear housing 10b located one rearward. A rack bar (output actuating member) 14 is supported on the gear housing 10b so as to move in a three-dimensional manner with the output shaft 13 so as to be axially movable.
The both 13, 14 are interlocked by an interlocking mechanism 15. In this embodiment, the interlocking mechanism 15 includes the output shaft 13
And a rack 15b formed in a part of the rack bar 14 and meshing with the pinion 15a. Both ends of the rack bar 14 are respectively connected to the left and right front wheels via steering links (both not shown). Are linked to.

Next, referring to FIGS. 1 and 2, a steering characteristic imparting mechanism 45 for transmitting the rotation of the intermediate rotating member 38 to the output shaft 13 while gradually reducing the reduction ratio in accordance with the increase of the rotation angle from the steering neutral position. Explain. A diametrically extending cam groove 47 is formed on the rear end surface of the intermediate rotation member 38, and a projection 48 is offset from the rotation axis O3 of the output shaft 13 by a distance R on the front end surface of the output flange 39 opposed to the cam groove 47. It is provided so as to project in the axial direction. This distance R is larger than the amount of eccentricity e between the rotation axes O2 and O3 of both members 38 and 13. The protrusion 48 is composed of a pin 48a fixed to the output flange 39 in parallel with the rotation axis O3, and a roller 48b rotatably provided on the pin 48a via a needle roller 48c. The cam groove 41 is rotatably engaged in the cam groove 41 with substantially no clearance.

The speed reducing mechanism 40, the steering characteristic imparting mechanism 45, and the interlocking mechanism 15 located in the gear housing 10b are lubricated with lubricating oil. In this embodiment, the cam groove 47 of the steering characteristic imparting mechanism 45 is provided on the side of the intermediate rotating member 38 so that the projection 4
Although 8 is provided on the output shaft 13 side, conversely, the protrusion 48 may be provided on the intermediate rotating member 38 side and the cam groove 47 may be provided on the output shaft 13 side.

As shown in FIG. 1, the front wheel steering system of this embodiment includes a hydraulic power steering system including a servo valve 20 and a power cylinder 30. The rotor valve member 21 of the servo valve 20 is integrally formed on the rear portion of the input side portion of the input shaft 11, and the sleeve valve member 22 has inner and outer peripheral surfaces that are the outer peripheral surface of the rotor valve member 21 and the inner peripheral surface of the valve housing 10a, respectively. Are rotatably fitted to each other and are connected to the rear half 11a of the input shaft 11 by the engagement pins 23. The valve housing 10a is formed with four ports of the servo valve 20, namely, an input port 25, an exhaust port 26 and a pair of distribution ports 27a and 27b.

On the other hand, the power cylinder 30 has a rack bar 14
A cylinder 31 that is provided in the middle of the gear housing 10b and that is formed integrally with the gear housing 10b and that penetrates the rack bar 14 coaxially and liquid-tightly; Then, it is constituted by a piston 32 that divides the inside into left and right working chambers. The left and right working chambers are communicated with the respective distribution ports 27a and 27b of the servo valve 20 by communication passages, and the input port 2
5 and the discharge port 26 are connected to the supply pump 35 and the reservoir 36 by communication passages, respectively.

The servo valve 20 is a torsion bar 1 which is operated by a torque acting between the input shaft 11 and its rear half 11a.
6 is operated according to a slight twist of the supply pump 35 to supply the working fluid from the supply pump 35 to each working chamber of the power cylinder 30 and to discharge the working fluid from each working chamber to the reservoir 36. It is controlled via 27a and 27b. As a result, steering assist force corresponding to the torque is applied to the front wheels via the rack bar 14. In addition,
Between the input shaft 11 and the latter half 11a thereof, both
Although a reaction force mechanism 29 for changing the power steering characteristic by changing the torsion spring characteristic between 1 and 11a is provided, the detailed structure is omitted.

Next, the operation of the above embodiment will be described.

When the input shaft 11 rotates together with the steering wheel (both not shown) via the handle shaft, the rear half 11a also rotates together via the torsion bar 16, and the intermediate rotary member 38 moves to the input pinion 41 and the input pinion 41. The speed is reduced by the speed reduction mechanism 40 including the internal gear 42 and rotated. As the intermediate rotating member 38 rotates to the left or right from the front wheel steering neutral position shown in FIG. 2, the roller 48b of the protrusion 48 rolls radially outward along the cam groove 47, and the output shaft 13 is rotated. This rotation is converted into an axial movement of the rack bar 14 via the interlocking mechanism 15, and the front wheels are steered via a link (not shown). The output shaft 13 with respect to the rotation angle α of the intermediate rotation member 38 and the rotation angle β of the input shaft 11 connected to the steering wheel.
The rotation angle θ of is as follows.

[0020]

## EQU1 ## α = tan ^-1 (sin θ / (cos θ-r)) β = tan ^-1 (sin θ / (cos θ-r)) / g where r = e / R g: reduction ratio of reduction mechanism 40 intermediate rotation The reduction ratio between the member 38 and the output shaft 13 is the differential value dθ / dα of the above equation, and gradually decreases as the intermediate rotation member rotation angle α approaches 180 degrees away from the neutral position, and increases after that. . The characteristic of the steering gear ratio with respect to the steering wheel rotation angle β is the differential value dθ / dβ of the following equation.
3 in proportion to the speed reduction ratio g of the speed reduction mechanism 40. That is, the steering gear ratio is large at the steering neutral position, gradually decreases as the steering wheel rotation angle increases, reaches a minimum value at a predetermined steering wheel rotation angle position corresponding to the speed reduction ratio g, and a steering wheel rotation angle higher than that. Then, there is an increasing tendency, that is, the opposite characteristic. The steering wheel rotation angle position where the steering gear ratio is the minimum is 18 when the speed reduction ratio g of the speed reduction mechanism 40 is 1, as shown in the figure.
It is 0 degree, and increases as the reduction ratio g increases. FIG. 3 shows an example in which the speed reduction ratio g is changed when r = 0.4.
In this embodiment, the reduction ratio g of the reduction mechanism 40 is 1.4.
The characteristic at that time is shown by a solid line. In this case, the steering wheel rotation angle position at which the steering gear ratio is the minimum is 252 degrees, but the stopper does not steer more than 240 degrees.

At the time of this steering, the power steering device including the servo valve 20, the reaction mechanism 29, the power cylinder 30, the supply pump 35 and the like operates to apply a steering assist force to the rack bar 14. A small amount of the hydraulic oil supplied from the supply pump 35 to the servo valve 20 and the reaction force mechanism 29 leaks from the O-ring 28, and the bearing 17b before the oil seal 49.
Is gradually accumulated in the space provided with, but is blocked by the oil seal 49 and the O-ring 11d, and the reduction mechanism 4
0, the steering characteristic imparting mechanism 45, the interlocking mechanism 15 and the like are not leaked into the gear housing 10b.

Valve housing 10a for maintenance and inspection
Even when the gear housing 10b and the gear housing 10b are disassembled from each other, the bearing retainer 19 to which the oil seal 49 is attached and the boss member 12 of the input pinion 41 with which the lip on the inner circumference of the oil seal 49 abuts are both on the valve housing 10a side. It is disassembled in the assembled state. Therefore, the servo valve 20
The hydraulic oil leaking from the reaction force mechanism 29 and accumulated in the space where the bearing 17b is located in the valve housing 10a is prevented by the oil seal 49 and does not leak to the gear housing 10b side. As a result, there is no risk that foreign working oil will mix into the lubricating oil in the gear housing and adversely affect the lubrication of each member in the gear housing.

The present invention can also be applied to a front wheel steering system using a mechanism other than a rack and pinion type such as a ball screw type and a worm pin type as the interlocking mechanism 15. Further, the invention can be applied not only to the front wheel steering device but also to the rear wheel steering device.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view of an embodiment of a steering device according to the present invention.

2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a diagram showing an example of a steering gear ratio characteristic of the steering device according to the present invention.

FIG. 4 is a side view in which a main part of a steering device according to a conventional technique is cut away.

[Explanation of symbols]

10 ... Housing, 10a ... Valve housing, 10b ... Gear housing, 11 ... Input shaft, 12 ... Boss member, 13 ...
Output shaft, 14 ... Output operating member (rack bar), 15 ... Interlocking mechanism, 19 ... Bearing retainer, 20 ... Servo valve, 30 ... Power cylinder, 38 ... Intermediate rotating member, 40 ... Reduction mechanism, 4
DESCRIPTION OF SYMBOLS 1 ... Input pinion, 42 ... Internal gear, 45 ... Steering characteristic provision mechanism, 49 ... Oil seal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoru Niwa 1 Toyota-cho, Toyota-shi, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Kiyoji Kawakami 1-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. ( 72) Inventor Kuyo Ikusei, Toyota-cho, Toyota-cho, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (1)

[Claims] 1. An input shaft that is connected to a steering handle and rotates together, an output operating member that is connected to the input shaft through an output shaft and an interlocking mechanism, and that steers a wheel through a steering link, and the output operating member. A power cylinder that applies an assist force to the output shaft, a servo valve that is provided on the input shaft and that operates according to the torque applied to the input shaft to change the assist force that the power cylinder applies to the output operating member, and a servo valve that supports the servo valve. A steering device including a housing including a valve housing, a gear housing that supports the interlocking mechanism, and an output shaft, wherein an intermediate rotating member eccentrically supported by the housing between the input shaft and the output shaft is provided. And an input pinion integrally provided at an end portion of the input shaft on the side of the intermediate rotating member and integrally provided at the intermediate rotating member. And a reduction mechanism for reducing the rotation of the input shaft and transmitting the rotation to the intermediate rotating member, and a liquid-tight seal from the input pinion side to the inner peripheral surface of the valve housing. A cylindrical bearing retainer which is inserted and presses and fixes the bearing supporting the input shaft to the valve housing, and an oil seal provided between an inner peripheral surface of the bearing retainer and an outer peripheral surface of the input pinion are provided. A steering device characterized by the above.