JPH0939823A - Steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device for a vehicle not only capable of changing a steering gear ratio in accordance with a steering angle of a steering wheel, but capable of optionally setting an steering angle characteristic suitable for the vehicle and extending freedom of design. SOLUTION: A steering device 10 for a vehicle is furnished with a rack bar 22 and a disc 30 to axially move by steering of a steering wheel 24, and an eccentric pin 36 of the disc 30 is put in a slit 46 of an oscillating link 42. When the rack bar 22 axially moves, the disc 30 is rotated while axially moving, the eccentric pin 36 oscillates the oscillating link 42 and a turning rod 12 is driven. As the eccentric pin 36 is rotated while axially moving, actual moving quantity increases, a pressurizing position of the oscillating link 42 is changed, and a lever ratio is changed. Consequently, a steering gear ratio is changed in accordance with a steering angle of the steering wheel 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system for steering steered wheels of a vehicle.

[0002]

2. Description of the Related Art In a vehicle steering system, a steering force is transmitted from a steering wheel to a steered wheel in order to cover a low speed range to a high speed range with a small steering amount (angle) without changing the steering wheel. A so-called variable gear ratio steering device has been proposed in which a variable gear ratio mechanism is provided in the path, and the steering gear ratio (steering angle ratio) can be changed according to the steering angle of the steering wheel (for example, Japanese Patent Laid-Open No. Hei 2 -216365).

In the variable gear ratio steering device disclosed in the above publication, an elliptical gear mechanism consisting of a pair of elliptical gears is interposed as a variable gear ratio mechanism in the steering force transmission path from the steering wheel to the steered wheels. . By using this elliptical gear mechanism, it is possible to obtain the characteristic that the steering gear ratio changes according to the increase of the steering angle of the steering wheel, and further, the steering response becomes too sensitive near the neutral position of the steering wheel. While preventing the steering wheel, the steering angle of the steering wheel required to fully steer the steering wheel can be reduced.

By the way, in the conventional steering apparatus having the variable gear ratio mechanism disclosed in the above publication, an elliptical gear mechanism composed of a pair of elliptical gears is used to change the steering gear ratio in accordance with the steering angle of the steering wheel. However, since these elliptical gears are required to have a special shape and high precision, it is difficult to manufacture them.Therefore, it is costly to satisfy the steering angle characteristics adapted to the vehicle. There was a drawback of becoming expensive.

In other words, since the steering device disclosed in the above publication uses an elliptical gear mechanism that is difficult to manufacture and expensive, it is possible to arbitrarily set the steering angle characteristic adapted to the vehicle. It is difficult, the application range of the vehicle is naturally limited, and the degree of freedom in design is low.

[0006]

In consideration of the above facts, the present invention can not only change the steering gear ratio according to the steering angle of the steering wheel, but also set the steering angle characteristic adapted to the vehicle arbitrarily. It is an object of the present invention to obtain a steering device for a vehicle that can be manufactured and has a greater degree of freedom in design.

[0007]

According to a first aspect of the present invention, there is provided a vehicle steering system including an output shaft for connecting left and right knuckle arms to steer the steered wheels and a steering wheel for steering wheel operation. And a rotating member that is rotatably supported by the moving member and always moves integrally with the moving member along the axis, and that has an eccentric pin provided at a position displaced from the center of rotation. An engaging member that is fixedly provided corresponding to the member and that rotates the rotating member by engaging with the rotating member that axially moves integrally with the moving member; Is engaged with the output shaft and the other end is engaged with an eccentric pin of the rotating member, and a swing member that transmits to the output shaft by swinging the axial movement and rotation of the rotating member, Eteiru.

In the vehicle steering system according to the first aspect, when the steering wheel is steered, the moving member is axially moved. When the moving member moves along the axis, the rotary member moves along with the moving member along the axis. At this time, the engaging member fixedly provided corresponding to the rotating member engages with the rotating member, and the rotating member is rotated. That is, when the moving member is axially moved, the rotating member is rotated while being axially moved integrally with the moving member.

When the rotating member is rotated while moving along the axis, the other end of the swinging member is pressed by the eccentric pin of the rotating member to swing the swinging member around the support shaft, whereby the output shaft moves. The steering wheel is steered by being pressed and driven by one end of the swing member.

In this case, the output shaft is driven at the transmission ratio determined by the lever ratio (arm ratio) according to the pressing position of the swing member by the eccentric pin.

Furthermore, since the rotating member is rotated while moving axially together with the moving member, the substantial amount of axial movement of the eccentric pin of the rotating member is rotated with respect to the amount of axial movement of the moving member. Substantially increased by the amount corresponding to the amount of rotation of the member. Furthermore, since the eccentric pin presses the swing member while the rotary member rotates, the pressing position of the swing member by the eccentric pin changes according to the rotation of the rotary member. In other words, the lever ratio (arm ratio) when swinging the swing member changes according to the rotation of the rotating member.

That is, since the rotating member swings the swinging member while moving and rotating along the axis, the ratio of the drive amount of the output shaft to the moving amount of the moving member (ie, the steering angle of the steering wheel) (steering gear). Ratio change characteristics)
Can be set non-linearly. In other words, it is possible to obtain a characteristic that the steering gear ratio changes non-linearly as the steering angle of the steering wheel increases. Therefore, by setting a large steering gear ratio near the neutral position of the steering wheel, it is possible to prevent the steering response from becoming too sensitive, while on the other hand, if the steering gear ratio is set small near the maximum steering angle of the steered wheels, steering can be reduced. The steering angle of the steering wheel required to fully steer the wheels can be reduced.

Further, by appropriately setting the eccentricity amount of the eccentric pin of the rotating member and the lever ratio (arm ratio) of the swinging member, it is possible to easily obtain the steering angle characteristic adapted to the vehicle, and to design it. Greater freedom.

[0014]

1 is a front view showing the overall structure of a vehicle steering system 10 according to an embodiment of the present invention. Further, FIG. 2 shows a front view of an operating state of the vehicle steering system 10.

The vehicle steering system 10 includes a steered rod 12 as an output shaft. The steered rod 12 is connected to a steered wheel 18 via a tie rod 16 connected to the knuckle arm 14, and the steered wheel 18 can be steered by moving in the axial direction. In addition, the steering rod 1
A rack 20 is formed at 2.

A rack bar 22 as a moving member is arranged near the steered rod 12. This rack bar 22
Is arranged in parallel with the steered rod 12, and further, a pinion 28 of a steering shaft 26 connected to a steering wheel 24 meshes with the steering wheel. Therefore, the rack bar 22 is axially moved by steering the steering wheel 24.

A disk 30 as a rotating member is arranged at the tip of the rack bar 22. As shown in detail in FIG. 3, the disk 30 is mounted on the rack bar 2 by bearings 32.
It is rotatably supported on the disc 2 and therefore the disc 30
And move along the axis. A gear portion 34 is formed on a part of the outer periphery of the disk 30, and the bearing 32 is further formed.
An eccentric pin 36 is fixed to a position eccentric from the center of rotation (that is, the center of rotation). A gear portion 34 of the disc 30 meshes with a rack bar 38 as an engaging member.

The rack bar 38 is located between the steered rod 12 and the rack bar 22, and like the rack bar 22, the steered rod 1 is provided.
2 are arranged in parallel with each other, and support portions 40 at both ends are fixed to the vehicle. As a result, the disk 30 can be rotated and moved along the rack bar 38.

On the other hand, a swing link 42 as a swing member is rotatably supported by a support shaft 44 between the disk 30 and the steered rod 12. A slit 46 is formed at one end of the swing link 42 in the longitudinal direction, and the eccentric pin 36 fixed to the disk 30 is slidably inserted therein. On the other hand, a gear portion 48 is formed at the other end of the swing link 42 in the longitudinal direction, and the rack 20 of the steered rod 12 is formed.
Are engaged. Therefore, the steering rod 12 can be driven by swinging the swing link 42.

In the vehicle steering system 10 having the above structure, when the steering wheel 24 is steered, the pinion 28 is rotated and the rack bar 22 is axially moved. When the rack bar 22 is moved along the axis, the disk 30 is integrally moved with the rack bar 22.
Is moved along the axis. At this time, the disc 30 is rotated by the engagement of the rack bar 38 fixedly provided corresponding to the disc 30 and the gear portion 34 of the disc 30. That is, when the rack bar 22 is axially moved,
The disk 30 is rotated while moving axially integrally with the rack bar 22.

When the disk 30 is rotated while moving axially, the slit 46 of the rocking link 42 is pressed by the eccentric pin 36 of the disk 30, and the rocking link 42 is rocked about the support shaft 44 as a fulcrum. The steering rod 12 is driven by meshing between the gear portion 48 of the swing link 42 and the rack 20 of the steering rod 12, and the steered wheels 18 are steered.

In this case, the steered rod 12 is driven at the transmission ratio determined by the lever ratio (arm ratio) corresponding to the pressing position of the swing link 42 by the eccentric pin 36.

Further, since the disk 30 is rotated while being axially moved integrally with the rack bar 22, the substantial axial movement amount of the eccentric pin 36 of the disk 30 is relative to the axial movement amount of the rack bar 22. And is substantially increased by the amount corresponding to the rotation amount of the disk 30. Furthermore, since the eccentric pin 36 presses the swing link 42 while the disc 30 rotates, the pressing position of the swing link 42 by the eccentric pin 36 changes according to the rotation of the disc 30. In other words, the lever ratio (arm ratio) when swinging the swing link 42 changes in accordance with the rotation of the disk 30.

For example, as shown in FIG. 3, when the disk 30 moves integrally with the rack bar 22 along the L ₁ axis, the disk 30 rotates in the direction of the arrow X, so that the eccentric pin 36 of the disk 30 moves substantially along the axis. The amount is substantially increased with respect to the axial movement amount L ₁ of the rack bar 22 by the movement amount L ₂ corresponding to the rotation amount of the disk 30. And furthermore,
Since the eccentric pin 36 presses the swing link 42 while the disc 30 rotates, the pressing position of the swing link 42 by the eccentric pin 36 changes from the A position to the B position according to the rotation of the disc 30. That is, the arm length (distance between the eccentric pin 36 and the support shaft 44) when swinging the swing link 42 is reduced by (L ₃ −L ₄ ).

That is, since the disk 30 swings the swing link 42 while moving and rotating along the axis, the steering rod 12 is driven with respect to the movement amount L ₁ of the rack bar 22 (that is, the steering angle of the steering wheel 24). The quantity ratio (change characteristic of the steering gear ratio) can be set non-linearly. In other words, it is possible to obtain the characteristic that the steering gear ratio changes non-linearly as the steering angle of the steering wheel 24 increases.

Therefore, by setting a large steering gear ratio near the neutral position of the steering wheel 24, it is possible to prevent the steering response from becoming too sensitive, while the steering gear ratio is reduced near the maximum steering angle of the steered wheels 18. If set, the steering angle of the steering wheel 24 required to fully steer the steered wheels 18 can be reduced.

Further, by appropriately setting the eccentric amount of the eccentric pin 36 of the disk 30 and the lever ratio (arm ratio) of the swing link 42, it is possible to easily obtain the steering angle characteristic adapted to the vehicle. Greater flexibility in design.

As described above, in the vehicle steering system 10 according to the present embodiment, not only the steering gear ratio can be changed according to the steering angle of the steering wheel 24, but also the steering angle characteristic adapted to the vehicle can be set arbitrarily. And the degree of freedom in design is greatly expanded.

[0029]

As described above, in the vehicle steering system according to the present invention, not only the steering gear ratio can be changed according to the steering angle of the steering wheel, but also the steering angle characteristic adapted to the vehicle can be arbitrarily set. This has the excellent effect of increasing design flexibility.

[Brief description of drawings]

FIG. 1 is a front view showing an overall configuration of a vehicle steering system according to an embodiment of the present invention.

FIG. 2 is a front view showing an operating state of the vehicle steering system according to the embodiment of the present invention.

FIG. 3 is a front view showing the relationship between the rack bar and the eccentric pin of the disk of the vehicle steering system according to the embodiment of the present invention.

[Explanation of symbols]

 10 Steering device for vehicle 12 Steering rod (output shaft) 18 Steering wheel 22 Rack bar (moving member) 24 Steering wheel 30 Disc (rotating member) 36 Eccentric pin 38 Rack bar (engaging member) 42 Swing link (swing) Material) 44 spindle

Claims (1)

[Claims] 1. An output shaft for connecting left and right knuckle arms to steer the steered wheels, a moving member connected to the steering wheel and axially moving according to a steering wheel operation, and rotatably supported by the moving member. The moving member is always axially moved integrally with the moving member, and the rotating member is provided with an eccentric pin at a position displaced from the center of rotation, and is fixedly provided corresponding to the rotating member, and is integrally formed with the moving member. An engaging member that engages with the rotating member that moves along the axis and that rotates the rotating member, and a swing shaft that is swingably supported, one end of which engages with the output shaft and the other end of which is the rotating member. A vehicle steering device comprising: a swing member that is engaged with an eccentric pin and that swings the axial movement and rotation of the rotary member to transmit the output shaft to the output shaft.