JP2504231B2 - Car steering device - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to a steering device capable of changing a transmission ratio of a wheel steering angle to a steering angle of an automobile.

(Prior Art) A steering apparatus for an automobile converts a rotational movement of a steering wheel into a lateral displacement movement of a tie rod via a rack and pinion gear mechanism, and then, the steering wheel is provided with right and left steering wheels at opposite ends thereof. However, the rotation amount of the steering wheel (steering wheel steering angle) and the wheel steering angle (wheel steering angle) are normally held in a constant correspondence relationship.

However, when the vehicle is traveling at high speed, the transmission ratio of the wheel steering angle to the steering wheel steering angle is increased to increase the transmission ratio of the wheel steering angle to the constant steering wheel steering angle to increase the size of the wheel steering angle to the constant steering wheel steering angle. It is desirable to make it small in order to secure running stability. On the other hand, when driving at low speed,
From the standpoint of speeding up the behavior of the vehicle to obtain a good driving feeling, or facilitating garage entry, the transmission ratio is inversely reduced to increase the wheel steering angle for a certain steering wheel steering angle. Is desirable.

Therefore, in order to meet the above requirements, for example,
As disclosed in Japanese Patent Application Laid-Open No. 62-31560, there is proposed a steering device in which the transmission ratio of the wheel steering angle to the steering wheel steering angle is changed according to the vehicle speed.

This steering system is provided with a planetary gear mechanism that changes the transmission ratio of the wheel steering angle to the steering angle in the steering force transmission path between the steering wheel and the tie rod. 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 unit that detects a driving state of a vehicle at a vehicle speed. A power steering mechanism is provided between the planetary gear mechanism and the tie rod.

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

(Problems to be Solved by the Invention) However, as described above, in the variable transmission ratio system using the planetary gear mechanism, the friction and backlash that occur between the sun gear, the ring gear, and the planetary gear that configure the planetary gear mechanism cause steering wheel steering. The above response causes play and deteriorates the steering feeling.
In addition, the steering function also causes a decrease in the actual steering angle and an increase in compliance steer.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce friction and backlash due to the rotation of each gear forming the planetary gear mechanism, and to reduce the friction on the steering wheel. An object of the present invention is to provide a steering device for an automobile that can improve the steering feeling and the steering function.

[Structure of the Invention] (Means and Actions for Solving the Problem) In order to achieve the above-mentioned object, the present invention provides a wheel rudder for a steering angle of a steering wheel in a steering force transmission path between a steering wheel and a tie rod. A planetary gear mechanism and a rack and pinion type gear mechanism for changing the angular transmission ratio are provided, and friction wheels made of elastic bodies rolling on each other are provided on the upper and lower parts of the sun gear, ring gear and planetary gears constituting the planetary gear mechanism. It is in.

Along with the sun gear, ring gear, and planetary gear that rotate as the steering wheel is steered, the friction wheel rolls to reduce friction and backlash between the gears.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows a schematic configuration of a steering device for an automobile. Reference numeral 1 denotes a steering handle, which is interlocked with a rotary valve 3 of the power steering device via a steering shaft 2. The rotary valve 3 is interlocked with a rack and pinion type gear mechanism 5 via a planetary gear mechanism 4 as a variable transmission ratio system, and a rack 7 meshing with a pinion 6 constituting the gear mechanism 5 is a tie rod extending in the width direction of the vehicle body. It is connected to wheels 9 and 9 via 8 and 8 and a knuckle arm (not shown). Further, the planetary gear mechanism 4 is provided with a stepping motor, which will be described later, for controlling the operation of the planetary gear mechanism 4 according to the operating state of the automobile.

The rotary valve 3 will be described with reference to FIGS.
As shown in FIG. 3, an input shaft 12 having a torsion bar 11 inserted therein is rotatably supported inside a housing 13 via bearings 14, 14. The rotary valve 3 is provided on the outer circumference of the input shaft 12. The housing 13 is provided with a first port 15 that communicates with an oil pump (not shown) and a second port 16 that communicates with an oil reservoir (not shown), and the left and right chambers of the cylinder tube respectively. Third and fourth ports 17, 18 communicating with each other are provided. The rotary valve 3 switches the pressure oil supplied to the cylinder tube in response to the steering of the steering wheel 1 and controls the pressure to assist the steering force of the steering wheel 1 to steer the wheels 9, 9. It is supposed to do.

The housing 13 of the planetary gear mechanism 4 is integrally provided in the housing 13 of the rotary valve 3. Inside the housing 19, a sun gear 20 is provided as an input gear fixed to the input shaft 12. A ring gear 21 is provided on the outer circumference of the sun gear 20, and the ring gear 21 is provided with bearings 22, 22 provided on an inner peripheral wall of the housing 19 and a projecting cylinder 13a projecting from the housing 13.
It is rotatably supported by. In addition, the Sangya 20
A plurality of planetary gears 23, which mesh with each other, are interposed between the ring gear 21 and the ring gear 21 at equal intervals. These planetary gears 23 are rotatably supported by a pinion shaft 24, and the pinion shaft 24 is supported by the pinion 6 of the rack and pinion gear mechanism 5.

Disc-shaped first friction wheels 20a, 20a formed of an elastic body made of rubber or a synthetic resin material are adhered to the upper and lower portions of the sun gear 20. Further, ring-shaped second friction wheels 21a, 21a formed of an elastic body made of rubber or a synthetic resin material are also bonded to the upper and lower portions of the teeth on the inner peripheral surface of the ring gear 21.
Further, disc-shaped third friction wheels 23a, 23a formed of an elastic body made of rubber or a synthetic resin material are adhered to the upper and lower portions of the plurality of planetary gears 23 ... Then, the first friction wheel 20a, 20a and the third friction wheel
23a and 23a are in contact with each other, and the second friction wheels 21a and 21a are in contact with the third friction wheels 23a and 23a. Therefore, with the rotation of the sun gear 20, the ring gear 21, and the planetary gear 23, the first, second, and third friction wheels 20a, 21a, and 23a roll contact while elastically contacting each other, resulting in friction between the gears, It reduces backlash and reduces noise generated by meshing.

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 rotary shaft 27 is meshed with the worm wheel 26. The rotating shaft 27 is directly connected to the stepping motor 29, and the rotation of the stepping motor 29 rotates the ring gear 21 via the worm 28 and the worm wheel 26. In other words, planetary gear 23
... is rolled between the sun gear 20 and the ring gear 21, and the amount of rotation of the pinion 6 is increased or decreased by the rolling of the planetary gear 23.

A flange portion 30 is integrally provided on the pinion 6,
The flange portion 30 is rotatably supported by a bearing 25 provided inside the casing 19, and the pinion shaft 24 is fixed to the flange portion 30. Further, a concave portion 31 is provided at the center of the flange portion 30, and a convex portion 32 provided at the tip portion of the input shaft 12 is fitted into the concave portion 31 via a bearing 33. Therefore, the input shaft 12 and the pinion 6 are positioned on the same axis, and the assembling workability is improved. Further, a rack 7 is meshed with the pinion 6, and the rack 7 is biased in the direction of the pinion 6 by a yoke spring 34.

Therefore, according to the embodiment, while the vehicle is running,
When the steering handle 1 is steered, this movement is transmitted to the rotary valve 3 of the power steering mechanism via the handle shaft 2, and the input shaft 12 rotates. As the input shaft 12 rotates, the sun gear 20 of the planetary gear mechanism 4 rotates. On the other hand, the steering angle of the steering wheel that changes with the steering of the steering wheel 1 is detected by the steering wheel angle sensor, and the vehicle speed at that time is detected by the vehicle speed sensor. Stepping motor 29 depending on the output signals of both sensors
When the rotation is controlled, worm 28, worm wheel 26
The ring gear 21 rotates via. That is, the planetary gears 23 ... Are rolled between the sun gear 20 and the ring gear 21, and the amount of rotation of the pinion 6 is increased / decreased by the rolling of the planetary gears 23. In the planetary gear mechanism 4, the sun gear 20 rotates by an angle proportional to the steering angle of the steering wheel 1, and at the same time, the ring gear 21 rotates according to the rotation angle of the stepping motor 29. For this reason, the pinion 6 rotates via the pinion shaft 24 due to the rolling of the planetary gears 23 ... The wheels 9, 9 are steered via the rack 7 and the tie rods 8, 8 meshing with the pinion 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 2 that constitutes the planetary gear mechanism 4
With the rotation of 0, the ring gear 21, and the planetary gear 23, the first, second, and third friction wheels 20a, 21a, and 23a elastically press and roll. First, second and third
Since the friction wheels 20a, 21a and 23a are formed of an elastic body, it is possible to reduce friction and backlash between the gears and noise generated by meshing.

As in the above-described embodiment, the planetary gears 23 forming the planetary gear mechanism 4 are integrally provided on the pinion 6 of the rack and pinion type gear mechanism 5, so that the planetary gear mechanism 4 and the gear mechanism 5 are close to each other. Can be placed and assembled in a state. Therefore, not only the apparatus is made compact, but also the strength is excellent, and the number of parts can be reduced.

[Effects of the Invention] As described above, according to the present invention, the upper and lower portions of the sun gear, the ring gear, and the planetary gear, which form the planetary gear mechanism that changes the transmission ratio of the wheel steering angle to the steering wheel steering angle, are in contact with each other. A friction wheel made of an elastic body was provided, and the friction wheel and backlash between the gears were reduced because the friction wheel was brought into rolling contact with the sun gear, ring gear, and planetary gear that rotate with the steering of the steering wheel. Therefore, there is an effect that the steering feeling on the steering wheel and the function of the steering can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of a steering device showing an embodiment of the present invention, FIG. 2 is a plan view partially in section, and FIG. 3 is a vertical cross-sectional side view showing a rolling contact state of a friction wheel. Four
The figure is also a schematic configuration diagram of the steering device. 1 ... Steering handle, 3 ... Rotary valve,
4 ... Planetary gear mechanism, 5 ... Rack and pinion gear mechanism, 8 ... Tie rod, 9 ... Wheels, 20 ... Sunga,
21 …… Ring guy, 23 …… Planetary guy, 20a, 21a,
23a ... Friction car.

Continuation of the front page (56) References JP-A-62-31560 (JP, A) Actually developed-SHO-52-145283 (JP, U) JP-B-62-8655 (JP, B2)

Claims (1)

(57) [Claims] 1. A steering apparatus for an automobile, comprising a planetary gear mechanism and a rack and pinion type gear mechanism for changing a transmission ratio of a wheel steering angle to a steering wheel steering angle in a steering force transmission path between a steering handle and a tie rod. A steering device for an automobile, comprising friction wheels made of elastic bodies rollingly contacting each other on the upper and lower parts of a sun gear, a ring gear, and a planetary gear that constitute the planetary gear mechanism.