JPH03153468A - Steering device for automobile - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) This invention relates to a steering device that can change the transmission ratio of wheel steering angle to steering wheel steering angle of an automobile.

(Prior Art) An automobile steering device converts the rotational movement of a steering wheel into a lateral displacement movement of a tie rod through a rack and pinion gear mechanism, and changes the direction of left and right steering wheels provided at both ends of the tie rod. The rotation Q of the steering wheel (steering wheel angle)
and the wheel turning angle (wheel steering angle) are usually always maintained in a constant correspondence relationship.

However, when the car is running at high speed, the transmission ratio of the wheel steering angle to the steering wheel steering angle is increased, and the transmission ratio of the wheel steering angle to the steering wheel steering angle is increased. It is desirable to reduce the size of the tire in order to ensure running stability. On the other hand, when driving at low speeds, from the standpoint of making the vehicle's behavior more agile to obtain a good driving feeling, or to make it easier to park in the garage,
It is desirable to conversely reduce the transmission ratio to increase the wheel steering angle for a constant steering wheel angle.

Therefore, in order to meet the above-mentioned requirements, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-31560,
A steering device has been proposed that changes the transmission ratio of a middle wheel steering angle to a steering wheel steering angle depending on the vehicle speed.

This steering device is provided with a planetary gear mechanism in a steering force transmission path between the steering handle and the tie rod, which changes the transmission ratio of the wheel steering angle to the steering wheel steering angle. This planetary gear mechanism is controlled by an actuator such as a stepping motor that operates based on a control signal from a controller that outputs a control signal in response to a signal from a driving state detection means that detects the driving state such as the vehicle speed. A power steering mechanism is provided between the R star gear mechanism and the tie rod.

Therefore, when the small wheels are steered by steering the steering wheel, the driving state of the vehicle at that time is detected by the first stage of the driving state detection device, and the actuator is activated based on the control signal from the controller that receives the output of this detection means. is activated, and the operation of the planetary gear mechanism is controlled by the operation of this actuator. The transmission ratio of the wheel steering angle to the steering wheel steering angle is variably controlled.

(Problem to be Solved by the Invention) However, as described above, the transmission north exit J-variation system using a planetary gear mechanism has no play! j! Friction and backlash that occur between the sun gear, ring gear, and planetary gears that make up the gear mechanism cause tactile response and play on the steering wheel, worsening the steering feeling. Furthermore, as a steering function, the actual steering angle decreases and compliance steering increases.

This invention was made with attention to the above-mentioned circumstances, and its purpose is to reduce the friction and backlash accompanying the rotation of each gear constituting the planetary gear mechanism, and to reduce the friction and backlash caused by the rotation of each gear constituting the planetary gear mechanism. An object of the present invention is to provide a steering device for an automobile that can improve steering feeling and steering function.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a steering force transmission path between the steering wheel and the tie rod, in which the wheel steering angle is adjusted to the steering wheel steering angle. A planetary tooth 11 mechanism and a rack and pinion gear mechanism are provided to improve the angular transmission ratio, and friction wheels made of elastic bodies that roll into contact with each other are provided at the upper and lower parts of the sun gear, ring gear, and planetary gear that constitute the planetary gear mechanism. That's true.

A friction wheel rolls into contact with the sun gear, ring gear, and planetary gear that rotate as the steering wheel is turned to reduce friction and backlash between each gear.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 4 shows a schematic configuration of a steering system for an automobile. Reference numeral 1 denotes a steering wheel, which is linked via a handle shaft 2 to a low-return valve 3 of a power steering system. The rotary valve 3 is interlocked with a rack and pinion gear mechanism 5 via a planetary gear mechanism 4 as a variable transmission system, and a rack 7 that meshes with a pinion 6 constituting the gear mechanism 5 has a tie rod 8 extending in the width direction of the vehicle body. .8 and a wheel 9.9 via a knuckle arm (not shown).

Further, the planetary gear mechanism 4 is provided with a stepping motor, which will be described later, which controls the operation of the planetary tMrli mechanism 4 according to the driving state of the automobile.

To explain the rotary valve 3, as shown in FIGS. 1 to 3, an input shaft 12 with a torsion bar 11 inserted therein has a bearing 14.
It is rotatably supported via the shaft. The rotary valve 3 is provided on the outer periphery of this human power shaft 12. The housing 13 is provided with a first boat 15 that communicates with an oil pump (not shown) and a second boat 16 that communicates with an oil reservoir (not shown). Third and fourth boats 17, 18 are provided which communicate with each other. This rotary valve 3 is connected to the steering handle 1.
In addition to switching the pressure oil supplied to the cylinder tube according to the steering of the steering wheel]
The wheels 9.9 are steered by assisting with the steering force.

A housing 19 of the planetary gear mechanism 4 is integrally provided with the housing 13 of the low-return valve 3.

A sun gear 20 as an input gear fixed to the human power shaft 12 is provided inside the housing 19.

A ring gear 21 is provided on the outer periphery of the sun gear 20, and the ring gear 21 is rotatably supported by bearings 22, 22 provided on the inner circumferential wall of the housing 19 and on the protruding cylinder 13a protruding from the housing 13. Further, between the sun gear 20 and the ring gear 21, there are a plurality of planetary gears 23 that mesh with each other.
・are spaced at equal intervals. These planetary gears 2
3... are rotatably supported by a pinion shaft 24, and this pinion shaft 24 is supported by a pinion 6 on the side 5 of the rack and pinion type gear machine.

Disc-shaped first friction wheels 20a, 20a made of an elastic body made of rubber or synthetic resin are bonded to the upper and lower parts of the sun gear 20. Furthermore, a ring-shaped second friction wheel 21 a s 21 formed of an elastic body made of rubber or synthetic resin material is also provided at the upper and lower parts of the southern part of the inner circumferential surface of the ring gear 21.
a is glued. Furthermore, disk-shaped third friction wheels 23a, 23a formed of an elastic body made of rubber or synthetic resin are bonded to the upper and lower parts of the plurality of planetary gears 23.

The first friction wheel 20a and the third friction wheel 23a, 23a are in contact with each other, and the second friction wheel 21a, 21a is in contact with the third friction wheel 238123B. Therefore, sun gear 20, ring gear 2
1 and planetary gear 23, the first, second, and third friction wheels 20a, 21a, and 23a roll into contact with each other while elastically pressing against each other, reducing friction and backlash between the respective gears and meshing. This reduces the noise generated by

Further, a worm wheel 26 is formed on the outer periphery of the ring gear 21 of the planetary gear mechanism 4, and a worm 28 fixed to a rotating shaft 27 is meshed with the worm wheel 26. The rotating shaft 27 is directly connected to a stepping motor 29, and the rotation of the stepping motor 29 rotates the ring gear 21 via a worm 28 and a worm wheel 26. That is, the planetary gears 23... are rolled between the sun gear 20 and the ring gear 21, and the planetary gears 23...
The rotation amount of the pinion 6 is controlled to increase or decrease by the rolling of the pinion 6.

The binion 6 is integrally provided with a flange portion 30,
This seven rung portion 30 is rotatably supported by a bearing 25 provided inside the casing 19, and the pinion shaft 24 is fixed to this flange portion 30. Further, a recess 31 is provided at the center of the flange portion 30, and a convex portion 32 provided at the tip of the input shaft 12 is fitted into this four portion 31 via a bearing 33. Therefore, the input shaft 12 and the pinion 6 are positioned on the same axis, which improves the ease of assembly. Furthermore, rack 7 is attached to this binion 6.
are engaged with each other, and this rack 7 is urged toward the pinion 6 by a yoke spring 34.

Therefore, according to the embodiment, when the steering wheel 1 is turned while the automobile is running, this movement is transmitted to the rotary valve 3 of the power steering mechanism via the steering wheel shaft 2, and the input shaft 12 is rotated. As the input shaft 12 rotates, the sun gear 20 of the planetary gear mechanism 4 rotates. On the other hand, the steering angle that changes as the steering wheel 1 is turned is detected by a steering wheel angle sensor, and the vehicle speed at that time is detected by a vehicle speed sensor. When the rotation of the two stepping motors is controlled by the output signals of both sensors, the ring gear 21 rotates simultaneously via the worm 28 and the worm wheel 26. That is, the planetary gears 23... are rolled between the sun gear 20 and the ring gear 21, and the planetary gears 23...
The rotation amount of the pinion 6 is controlled to increase or decrease by the rolling of the pinion 6.

In the planetary gear mechanism 4, the sun gear 20 rotates by an angle proportional to the steering angle of the steering handle 1, and at the same time, the ring gear 21 rotates according to the rotation angle of the stepping motor 29. Therefore, the rolling of the planetary gears 23 of the planetary gear mechanism 4 causes the pinion 6 to rotate via the pinion shaft 24, but the pinion 6 rotates by an angle that is increased or decreased relative to the steering angle. The wheels 9.9 are steered via the rack 7 and tie rods 8.8 that mesh with the binions 6, and the transmission ratio of the wheel steering angle to the steering wheel steering angle is variably controlled.

At this time, the sun gear 20 constituting the a-spin gear mechanism 4
, as the ring gear 21 and the planetary gear 23 rotate, the first, second and third friction wheels 20 a % 21
a and 23a come into rolling contact while being elastically pressed against each other. First, second and third friction wheels 20a, 21a and 23
Since a is made of an elastic body, friction and backlash between the gears can be reduced, and noise caused by meshing can be reduced.

As in the embodiment described above, the rack and pinion gear mechanism 5
By integrally providing the planetary gears 23 constituting the planetary gear mechanism 4 on the pinion 6, the planetary gear mechanism 4 and the gear mechanism 5 can be disposed and assembled in close proximity. Therefore, not only can the device be made more compact, but it is also superior in strength, and the number of parts can be reduced.

[Effects of the Invention] As explained above, according to the present invention, there is a shift control system that changes the transmission ratio of the wheel steering angle to the steering wheel steering angle.
Friction wheels made of elastic bodies that roll into contact with each other are provided above and below the sun gear, ring gear, and planetary gear that make up the vehicle mechanism, so that the friction wheels come into rolling contact with the sun gear, ring gear, and planetary gear that rotate as the steering wheel is turned. Therefore, the friction and backlash between the gears can be reduced, and the steering feeling on the steering wheel and the steering function can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a steering device showing an embodiment of the present invention, FIG. 2 is a partially sectional plan view, and FIG. 4
The figure is also a schematic configuration diagram of the steering device. DESCRIPTION OF SYMBOLS 1... Steering handle, 3... Rochry valve, 4... Planetary gear mechanism, 5... Rack and pinion type gear mechanism, 8... Tie rod, 9... Wheel, 20...
...Sun gear, 21...Ring gear, 23...Planetary gear, 20a, 21a, 23a-...Friction wheel.

Claims (1)

[Claims] A steering device for an automobile that is provided with a planetary gear mechanism and a rack and pinion gear mechanism that change the transmission ratio of wheel steering angle to steering wheel steering angle in a steering force transmission path between a steering handle and a tie rod, wherein the planetary gear mechanism is A steering device for an automobile, characterized in that a friction wheel made of an elastic body that rolls into contact with each other is provided above and below a sun gear, a ring gear, and a planetary gear.