JPH03153469A - car steering device - Google Patents

Abstract

PURPOSE:To enhance a steering feeling by halving a tooth part of each gear of a planetary gear mechanism, changing the transmission ratio of a wheel steering angle with a steering wheel steering angle, installed in a steering force transmission route, in the facewidth direction, and forming each tooth part into a different module or different tooth part form. CONSTITUTION:A rotary valve 3 set up on the circumference of an input shaft 12 being connected to a steering shaft is linked up with a rack-and-pinion type gear mechanism 5 via a planetary gear mechanism 4, and a rack 7 is moved in the axial direction by rotation of a pinion 6 of the said mechanism 5, thereby steering wheels. The planetary gear mechanism 4 consists of a sun gear 20 attached tight to the input shaft 12, a ring gear 21 supported on the inner circumference of a housing 19, and planetary gears 23 in mesh with both these gears 20, 21. Then, each of these gears 20, 21 and 23 is halved of its tooth part in the width direction, and each tooth part is formed into a different module or different tooth part form so that possible friction backlash in each gear is reduced in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) This invention relates to a steering device that can change the transmission ratio of the rl single wheel steering angle to the steering angle of the steering wheel 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 amount of rotation of the steering wheel (steering angle)
and the wheel turning angle (wheel steering angle) are usually always maintained in a constant correspondence relationship.

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

This steering device is provided with a J star gear mechanism that changes the transmission ratio of the wheel steering angle to the steering wheel steering angle in a steering force transmission path between the steering handle and the tie rod. This a-star 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 of the automobile. A power steering mechanism is provided between the planetary centering mechanism and the tie rod.

Therefore, when the steering wheel is turned to turn the wheels, the driving state of the vehicle at that time is detected by the driving state detection means, and the actuator is actuated based on the control signal from the controller that receives the output of this detection means. , 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 variable transmission ratio system using the R star gear mechanism has a problem in that the sun gear, which constitutes the planetary gear mechanism,
Friction and backlash that occur in the ring gear and the brane gear make the steering wheel feel rough and loose, worsening the steering feel. Furthermore, as a steering function, the actual steering angle decreases and compliance steering increases.

This invention was made in view of the above-mentioned circumstances, and its purpose is to reduce the friction and backlash caused by the rotation of the valley gears constituting the planetary gear mechanism, and to reduce the friction and backlash that occur 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 steering function of the vehicle.

[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. An ilI star gear mechanism that changes the angular transmission ratio is provided, and this i! ! The sun gear that makes up the star gear mechanism,
The teeth of the ring gear and planetary gear are aligned 2 times in the tooth width direction.
The reason lies in the fact that the two teeth are divided into different modules or have different tooth shapes.

To maintain meshing alignment of gears and reduce backlash without increasing friction between each gear of a sun gear, a ring gear, and a planetary gear that rotate with the steering of a steering wheel.

(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 handle, which is linked via a handle shaft 2 to a low-return valve 3 of a power steering system. This 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 that meshes with a pinion 6 constituting this 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).

Also, the i! ! The star gear mechanism 4 is provided with a stepping motor, which will be described later, which controls the operation of the planetary gear mechanism 4 according to the driving state of the vehicle.

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 the input 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 and 18 are provided which communicate with each other. And this low revalve 3 is the steering handle 1
In addition to switching the pressure oil supplied to the cylinder tube according to the steering of the steering wheel 1,
The wheels 9.9 are steered by assisting with the steering force.

The housing 13 of the rotary valve 3 is integrally provided with a housing 19 of the iU gear machine side 4.

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

A ring gear 21 as an output gear is provided on the outer periphery of the sun gear 20, and the ring gear 21 is rotatably supported by bearings 22 and 22 provided on the inner circumferential wall of the housing 19 and the protruding cylinder 13a protruding from the housing 13. ing. Furthermore, a plurality of planetary gears 23 are interposed at equal intervals between the sun gear 20 and the ring gear 21 and mesh with each other. 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.

The tooth portion of the sun gear 20 is divided into two in the tooth width direction, and an upper tooth portion 20a and a lower tooth portion 20b are formed.
A ring-shaped four part 20c is formed between a and 20b. Therefore, the sun gear 20 has a spool shape, and the upper tooth portion 20a and the lower tooth portion 20b are formed in different modules. Further, the ring gear 21
The tooth portion on the inner circumferential surface is also divided into two in the tooth width direction, forming an upper tooth portion 21a and a lower tooth portion 21b.
A ring-shaped four part 21c is formed between and 21b.

Further, the upper tooth portion 21a and the lower tooth portion 21b are formed in different modules. Further, the tooth portions of the plurality of planetary gears 23 are divided into two in the tooth width direction, forming an upper ridge portion 23a and a lower southern portion 23b, and an annular recess 23c between both tooth portions 23a and 23b. is formed. Therefore, the planetary gear 23 has a spool shape, and the upper tooth portion 23B and the lower tooth portion 23
It is formed in a module different from b.

And, without increasing the friction between the sun gear 20, ring gear 21, planetary gear 23, etc., the meshing alignment of the gears is maintained and backlash is reduced.

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 co-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. In other words, the planetary gears 23... are transferred 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.

A flange portion 30 is integrally provided on the pinion 6,
This flange portion 30 is rotatably supported by a bearing 25 provided inside the casing 19, and the binion shaft 24 is fixed to this flange portion 30. Furthermore, a four part 31 is provided at the center of the flange part 30, and a convex part 32 provided at the tip of the input shaft 12 is fitted into this four part 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 pinion 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 steered while the mower is running, this movement is transmitted to the rotary valve 3 of the power steering mechanism via the handle shaft 2, and the human power shaft 12 is rotated. As the human power shaft 12 rotates, the sun gear 20 of the planetary gear mechanism 4 rotates. On the other hand, the steering wheel steering angle that changes as the steering wheel 1 is turned is detected by the steering wheel steering angle sensor, and the vehicle speed at that time is detected by the vehicle speed sensor. When the stepping motor 29 is rotationally controlled by the output signals of both sensors, the ring gear 21 is rotated via the worm 28 and the worm wheel 26.

In other words, the planetary gears 23... are rolled between the sun gear 20 and the ring gear 21, and the planetary gears 23...
The amount of rotation 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 planetary gear mechanism 4
, the ring gear 21, the planetary gear 23, etc., mesh with each other, but each tooth is divided into upper and lower halves and formed into different modules, so that the friction between the gears can be maintained without increasing the friction between the gears. Can maintain meshing alignment and reduce backlash.

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.

In the above embodiment, the upper and lower tooth portions of the sun gear 20, the ring gear 21, and the planetary gear 23 are made into different modules, but the present invention is not limited to the above embodiment, and the sun gear 20, the ring gear 23... 21 and planetary gear 23... Even if the upper stage is a spur gear and the lower stage is a helical gear, the meshing alignment of the gears is maintained without increasing the friction between each gear,
Backlash can be reduced.

"Effects of the Invention" As explained above, according to the present invention, the tooth portions of the sun gear, ring gear, and planetary gear that constitute the planetary gear mechanism that change the transmission ratio of the wheel steering angle to the steering wheel steering angle are arranged in two directions in the tooth width direction. Since the teeth are divided into different modules or have different tooth shapes, gear meshing alignment can be achieved without increasing the friction between the sun gear, ring gear, and planetary gear that rotate as the steering wheel is turned. can be maintained and backlash can be reduced.

Therefore, there is an effect that the steering feeling on the steering wheel and the steering function can be improved.

[Brief explanation of the drawing]

FIG. 3 is a longitudinal sectional side view showing a part of the planetary gear mechanism, and FIG. 4 is a schematic configuration diagram of the steering device. 1... Steering handle, 3... Rotary knob, 4... R star gear mechanism, 8... Tie rod, 9
... Wheel, 20 ... Sun gear, 21 ... Ring gear, 23 ... Planetary gear, 20 a s 20
b s 21. a 521b, 23a, 23b-...
Teeth.

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 the tooth portions of a sun gear, a ring gear, and a planetary gear are divided into two in the tooth width direction, and both tooth portions have different modules or different tooth shapes.