JP3123397B2 - Variable steering angle ratio steering system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable steering angle ratio steering apparatus for a vehicle, and more particularly to a variable steering angle ratio steering apparatus for a vehicle which can change a ratio between a steering operation angle and a steering angle of a steered wheel.

[0002]

2. Description of the Related Art Conventionally, in vehicles such as automobiles, there is known a vehicle steering angle ratio variable steering device capable of changing a ratio between a steering operation angle and a steering wheel turning angle in accordance with a vehicle speed. One example is disclosed in Japanese Patent Application Laid-Open No. 6-234467.

As shown in FIG. 4, in this variable steering angle ratio steering apparatus for a vehicle, a rack 74 is moved in the axial direction by a pinion 72 connected to a shaft 70A of a steering 70, and this movement causes the rack 74 to swing. A sliding pin 80 engaged with an elongated hole 78 provided in the lever 76 swings the swing lever 76 about a fulcrum pin 82, and a relay rod 86 pivotally supported by the swing lever 76 by a pin 84. Are moved in the axial direction to steer the steered wheels 88. Then, the position of the fulcrum pin 82 is moved in a direction (arrow Y direction in FIG. 4) orthogonal to the rack 74 and the relay rod 86, and the distance W1 between the fulcrum pin 82 and the pin 80 is changed.
By changing the ratio of the distance W2 between the fulcrum pin 82 and the pin 84, the ratio between the steering operation angle and the steering wheel turning angle can be changed.

[0004]

However, in this vehicular steering angle ratio variable steering apparatus, the rotational movement of the steering wheel 70 is converted into the linear movement of the rack 74, and this rack 7
4 is converted into a swinging motion of the swinging lever 76, and further, the swinging motion of the swinging lever 76 is converted into a linear movement of the relay rod 86. Therefore, there is a problem that the moving range of each component member is widened and the size of the apparatus is increased.

In view of the above facts, the present invention can change the ratio between the steering operation angle and the steering angle of the steered wheels according to the running condition of the vehicle, and can reduce the size of the apparatus. The aim is to obtain a steering device.

[0006]

According to a first aspect of the present invention, there is provided a vehicle steering angle ratio variable steering apparatus according to the present invention, wherein an input shaft which rotates in response to a steering operation, and which moves in a longitudinal direction in accordance with the rotation of the input shaft. Moving means, an output shaft connected to the steered wheels and arranged substantially parallel to the longitudinal direction of the moving means at a steering neutral position, an engaging portion provided on the moving means and engaging with the output shaft, Rotating means for rotating the moving means around the axis of the input shaft.

Therefore, according to the present invention, when the input shaft rotates in response to the steering operation and the moving means moves in the longitudinal direction by the rotation of the input shaft, the engaging portion provided on the moving means causes The output shaft moves in the axial direction and the steered wheels are steered. At this time, when the moving means is rotated about the axis of the input shaft by the rotating means, the output shaft moves in the axial direction by the engaging portion provided on the moving means, and is combined with the movement of the output shaft by the steering operation. The ratio between the steering operation angle and the steering wheel turning angle changes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a variable steering angle ratio steering apparatus for a vehicle according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, in a vehicular steering angle ratio variable steering apparatus 10 according to this embodiment, a steering main shaft 12 as an input shaft is inserted into a main rack housing 14 fixed to a vehicle body side. 14A.

As shown in FIG. 2, bearings 16 and 18 are disposed between the inner peripheral surface of the insertion portion 14A of the main rack housing 14 and the steering main shaft 12, and the steering main shaft 12 is steered. The main shaft 12 is rotatably supported in the direction around the axis P1 (the direction of arrow A in FIG. 2). Near the tip of the steering main shaft 12, a pinion gear 2 is provided.
0 is formed, and the pinion gear 20 is inserted into a subrack housing 22 as a part of the moving means.

Bearings 24, 2 are provided between the inner peripheral surface of the subrack housing 22 and the portions 12A, 12B of the steering main shaft 12 which sandwich the pinion gear 20.
The subrack housing 22 is rotatable in the direction around the axis P1 of the steering main shaft 12 (the direction of arrow B in FIG. 2).

As shown in FIG. 1, the subrack housing 22 extends in a direction perpendicular to the steering main shaft 12 (in a direction indicated by an arrow C1 in FIG. 1). Are formed along the arc. A spur gear 30 as a part of the rotating means is formed on the outer periphery of the convex part 28. The spur gear 30 has a worm gear 3 as a part of the rotating means.
2 is screwed.

Therefore, when the worm gear 32 rotates,
Together with the spur gear 30, the subrack housing 22 rotates in a direction around the axis P1 (the direction of arrow B in FIG. 1).

The worm gear 32 is fixed to a rotating shaft of a motor 34 as a part of a rotating means.
Are connected to a control circuit not shown. Also,
A vehicle speed sensor (not shown) is connected to the control circuit, and the control circuit controls the motor 34 based on a detection value of the vehicle speed sensor and the like.

A subrack 36 as a part of the moving means penetrates through the subrack housing 22 in the longitudinal direction. Bushes 38 and 40 are disposed between the inner peripheral surfaces of the vicinity 22A and 22B of the subrack housing 22 at both ends in the longitudinal direction and the subrack 36.
Reference numerals 8 and 40 support the subrack 36 movably in the axial direction (the direction of the arrow C1 in FIG. 1). In the vicinity 22A, 22B of both ends in the longitudinal direction of the subrack housing 22,
Protrusions 42 and 44 are formed.

As shown in FIG. 2, the projections 42, 44
The sub-rack 36 is formed at a position facing the back surface 36B of the tooth portion 36A, and a compression spring 46 is inserted into the projections 42 and 44, respectively. By the compression spring 46, the teeth 36A of the subrack 36 always mesh with the pinion gear 20 of the steering main shaft 12.

As shown in FIG. 1, an opening 48 is formed along the longitudinal direction of the subrack housing 22 on the side of the subrack housing 22 opposite to the projection 28.
A pendulum portion 50 extending from the subrack 36 projects from the opening 48, and a slit 52 is formed in the pendulum portion 50 as an engaging portion extending along the radial direction of the steering main shaft 12. ing.

When the subrack housing 22 is in the neutral position (the state shown in FIG. 1), a main rack 54 as an output shaft is arranged in parallel with the subrack housing 22 and the subrack 36. Main rack 54
A pin 56 is provided upright, and this pin 56 is engaged with the slit 52 of the subrack 36. Therefore, the subrack 36 is positioned in the axial direction of the subrack 36 (arrow C1 in FIG. 1).
Direction), and the subrack 36 moves along the axis P1.
When the main rack 54 rotates in the rotation direction (the direction of the arrow B in FIG. 1), the main rack 54 moves in the axial direction of the main rack 54 (the direction of the arrow C2 in FIG. 1). The main rack 54 is connected to left and right steering wheels (not shown) via a well-known connecting member.

Next, the operation of the embodiment will be described. In the vehicular steering angle ratio variable steering device 10 according to the present embodiment, when the pinion gear 20 formed on the steering main shaft 12 rotates in the direction of arrow B in FIG. 2 in accordance with the steering operation, the pinion gear 20 and the tooth portion 36A are formed. The subrack 36 meshed with the sub-rack moves in the direction of the arrow C1 in FIG.
Move in one direction. By this movement, the main rack 54, which is engaged with the slit 52 of the pendulum unit 50 by the pin 56, moves in the direction of arrow C2 in FIG. 1, and the steered wheels connected to the main rack 54 are steered.

In the vehicle steering angle ratio variable steering apparatus 10 according to the embodiment, when the rotation shaft of the motor 34 is rotated by the control of the control circuit according to the running state of the vehicle, the worm gear 32 is rotated. , A subrack housing 22 having a spur gear 30 screwed to a worm gear 32 is shown in FIG.
In the direction of arrow B.

For this reason, the ratio of the steering operation angle to the steering wheel turning angle can be changed by simultaneously operating the steering wheel 12 and rotating the motor 34. For example, as shown in FIG. 3, the subrack 36 moves in the direction of arrow D in FIG.
, The movement of the slit 52 becomes a large movement amount α equivalent to the rotation about the virtual center axis P2 offset from the axis P1 to the opposite side to the main rack 54, and the arrow of the main rack 54 The amount of movement in the F direction also increases.

Therefore, when the vehicle is running at high speed, the motor 34 is not rotated or the slit 52
By rotating the steering wheel in a direction in which the movement amount α of the steering wheel becomes smaller and reducing the ratio of the steering wheel turning angle to the steering operation angle, it becomes easier to ensure running stability. On the other hand, when the vehicle is running at a low speed, the motor 34 is rotated in the direction in which the movement amount α of the slit 52 is increased, and the ratio of the turning angle of the steered wheels to the steering operation angle is increased, so that the garage can be moved. Becomes easier.

In the vehicle steering angle ratio variable steering apparatus 10 according to the present embodiment, the subrack 36 moves in the axial direction,
In addition, since the subrack 36 is configured to rotate in the direction around the axis P1, the moving range of each component is narrow. In particular, since the rotation trajectory of the subrack housing 22 and the subrack 36 is small, the device can be downsized and the vehicle can be downsized. The mountability of is improved.

In the vehicular steering angle ratio variable steering apparatus 10 according to the present embodiment, the motor 34
By rotating 6 in the direction around the axis P1, automatic driving becomes possible.

[0025]

According to the first aspect of the present invention, there is provided a vehicle steering angle ratio variable steering apparatus comprising: an input shaft which rotates in accordance with a steering operation; a moving means which moves in a longitudinal direction in accordance with the rotation of the input shaft; An output shaft connected to the wheels and arranged substantially parallel to the longitudinal direction of the moving means at the steering neutral position, an engaging portion provided on the moving means and engaging with the output shaft, and moving the moving means around the axis of the input shaft. And a rotating means for rotating, so that the ratio between the steering operation angle and the steering angle of the steered wheels can be changed in accordance with the running state of the vehicle and the like. Have.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a neutral state of a vehicular steering angle ratio variable steering apparatus according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing a vehicle steering angle ratio variable steering device according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram of an operation of the vehicle steering angle ratio variable steering device according to the embodiment of the present invention;

FIG. 4 is a plan view showing a vehicle steering angle ratio variable steering device according to a conventional embodiment.

[Explanation of symbols]

 Reference Signs List 10 variable steering angle ratio steering device for vehicle 12 steering main shaft (input shaft) 22 subrack housing (moving means) 30 spur gear (rotating means) 32 worm gear (rotating means) 34 motor (rotating means) 36 subrack (moving means) ) 50 Pendulum part 52 Slit (engagement part) 54 Main rack (output shaft) 56 pin

Claims (1)

(57) [Claims] 1. An input shaft that rotates in response to a steering operation, a moving unit that moves in a longitudinal direction according to the rotation of the input shaft, and a longitudinal direction of the moving unit that is connected to a steered wheel and is at a steering neutral position. An output shaft arranged substantially in parallel, an engaging portion provided on the moving unit and engaging with the output shaft, and a rotating unit for rotating the moving unit around the axis of the input shaft. A variable steering angle ratio steering device for a vehicle.