JPH0948365A - Steering angle ratio variable steering gear for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert a steering angle ratio according to the running condition and the like of a vehicle, and to make a device in a small size. SOLUTION: A gear 16 is connected to a steering shaft 12, and a gear 18 is engaged to the gear 16. The gear 18 is supported to a shaft 20, and a swing arm 22 is supported allowable to fluctuate to the shaft 20. A circular arc form groove 26 is formed to the swing arm 22, and the front end 30B of an arm 30 extending integrally from a relay rod 28 in the diameter direction is engaged to the groove 26. To the arm 30, a rod 34 of a power cylinder 32 for gear ratio variation is supported rotatable through a shaft 36. The end 38A of a cylinder 38 of the power cylinder 32 for gear ratio variation is supported rotatable to a base 22A of the swing arm 22 through a shaft 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering angle ratio variable steering system, and more particularly to a vehicle steering angle ratio variable steering system capable of changing a steering angle ratio (steering gear ratio) according to a vehicle speed or the like. .

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, there has been known a vehicle steering angle ratio variable steering device capable of changing a steering gear ratio according to a vehicle speed, one example of which is Japanese Patent Laid-Open No. 6-234367. It is shown in the official gazette.

As shown in FIG. 8, in this vehicle steering angle ratio variable steering system, a rack 74 is moved in the axial direction by a pinion 72 connected to a shaft 70A of a steering wheel 70, and the rack 74 is swung by this movement. The sliding pin 80 engaged with the long hole 78 provided in the lever 76 is the fulcrum pin 82.
The swing lever 76 is swung about the center of the steering wheel, the relay rod 86 pivotally supported by the swing lever 76 is moved in the axial direction by the pin 84, and the steered wheels 88 are steered. The position of the fulcrum pin 82 is orthogonal to the rack 74 and the relay rod 86 (arrow Y in FIG. 8).
Direction), and the distance W between the fulcrum pin 82 and the pin 80
The steering gear ratio can be changed by changing the ratio of 1 and the distance W2 between the fulcrum pin 82 and the pin 84.

[0004]

However, in this vehicle steering angle ratio variable steering system, the rotational movement of the steering wheel 70 is converted into the linear movement of the rack 74, and the rack 7 is rotated.
4 is converted into the swing motion of the swing lever 76, and the swing motion of the swing lever 76 is converted into the straight motion of the relay rod 86. Therefore, there is a problem that the moving range of each component is widened and the device becomes large.

In consideration of the above facts, the present invention can change the steering gear ratio according to the running state of the vehicle,
Moreover, it is an object of the present invention to obtain a variable steering angle ratio steering device for a vehicle that can be downsized.

[0006]

According to a first aspect of the present invention, there is provided a variable steering angle ratio steering device for a vehicle according to a first aspect of the invention. An input shaft that rotates in response to a steering operation, an output shaft that is connected to steered wheels, and the output. An oscillating means that is rotatably supported around an axis in a direction intersecting the axis and oscillates in accordance with the rotation of the input shaft; and an arm portion that integrally extends from the output shaft in the radial direction of the output shaft. Engaging position adjusting means for moving an engaging position between the arm portion and the swinging means in a radial direction from a swing center of the swinging means,
It is characterized by having.

Therefore, in the steering angle ratio variable steering apparatus for a vehicle according to the first aspect of the present invention, the input shaft rotates in response to the steering operation, and when the rocking means rocks, the rocking means engages. The output shaft moves in the axial direction through the arm portion, and the steered wheels are steered.

Here, when the engagement position adjusting means moves the engagement position between the arm portion and the swinging means in a radial direction from the swing center of the swinging means, the arm portion moves with respect to the swinging angle of the swinging means. The amount changes. Therefore, the amount of movement of the output shaft changes, and the steering gear ratio changes.

Therefore, for example, when the vehicle speed is low such as when the vehicle is parked in the garage, the steering wheel ratio can be reduced by moving the engagement position between the arm portion and the swinging means by the engagement position adjusting means to reduce the steering gear ratio. It is possible to set so that the turning angle of the steered wheels becomes larger with respect to the steering amount. On the other hand, when the vehicle is traveling at a high speed, if the engagement position adjusting means moves the engagement position between the arm portion and the swinging means to increase the steering gear ratio, the turning angle of the steered wheel with respect to the steering amount of the steering wheel is increased. Can be set to be smaller.

According to a second aspect of the present invention, in the vehicle steering angle ratio variable steering device according to the first aspect, the steering force assist mechanism and the engagement position from the swing center when the steering force assist mechanism is abnormal. And driving means for maximizing the distance.

Therefore, when the assist mechanism is abnormal, the drive means sets the engagement position between the swinging means and the arm portion to the maximum distance from the swing center, so that the steering gear ratio becomes small.

According to a third aspect of the present invention, in the vehicle steering angle ratio variable steering device according to the second aspect, there is provided deceleration means for decelerating an input from the input shaft in association with the drive means. It has a feature.

Therefore, when the assist mechanism is abnormal, the decelerating means decelerates the input from the input shaft in cooperation with the driving means, so that the steering force is reduced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of a vehicle steering angle ratio variable steering system of the present invention will be described with reference to FIGS.

As shown in FIG. 1, in a vehicle steering angle ratio variable steering system 10 of the present embodiment, a steering shaft 12 as an input shaft that interlocks with a steering wheel (not shown).
A gear 16 is connected to a gear 16 via a rotary valve 14 that constitutes a part of a steering force assist mechanism (power steering system). A gear 18 meshes with the gear 16.

The gear 18 is supported by a shaft 20 supported on the vehicle body side, and the shaft 20 is arranged in parallel with the steering shaft 12. The shaft 20 has a swing arm 22 as a swing means.
However, the swing arm 22 is swingable in a direction around the axis P of the shaft 20 (direction of arrow A in FIG. 1).

The swing arm 22 has a base portion 22A extending in the axial direction of the shaft 20, and the gear 1 of the base portion 22A.
A shaft 24 projects at the end opposite to 8 (on the left side in FIG. 1). The shaft 24 is rotatably supported on the vehicle body side via a bearing 26. The swing arm 22 is
Arm portion 2 protruding in the radial direction of shaft 20 (upward in FIG. 1)
2B, and an arc-shaped groove 26 is formed in the arm portion 22B. The groove 26 is formed to be convex toward the gear 18 from the shaft 24 side toward the gear 18 side.

At the center of the circular arc shape of the groove 26,
A relay rod 28 serving as an output shaft is provided, and the relay rod 28 is provided in a direction intersecting the axis P of the shaft 20 (direction of arrow B in FIG. 2) and indicated by arrow B in FIG.
It is supposed to be movable in any direction. On the relay rod 28,
A base portion 30A of an arm 30 as an arm portion is fixed, and the arm 30 extends from the relay rod 28 to the relay rod 2
8 integrally extends in the radial direction. Also, the arm 30
The tip portion 30B of is engaged with the groove 26.

As shown in FIG. 1, an end portion 34A of a rod 34 of a gear ratio changing power cylinder 32 as an engagement position adjusting means is rotatably supported by a shaft 36 on an intermediate portion 30C of an arm 30. There is. On the other hand, the end portion 38A of the cylinder 38 of the gear ratio changing power cylinder 32 is rotatably supported by the shaft 22 on the base portion 22A of the swing arm 22.

Therefore, when the gear ratio varying power cylinder 32 is actuated by a control device (not shown), the distal end portion 30B of the arm 30 moves along the groove 26 according to the expansion and contraction of the rod 34, and the arm 30 moves. Relay rod 28
It is configured to swing in the clockwise direction of FIG. 1 (direction of arrow C in FIG. 1) and the counterclockwise direction of FIG. 1 (direction of arrow D in FIG. 1).

Next, the operation of the first embodiment will be described. In the vehicular steering angle ratio variable steering apparatus 10 of the first embodiment, when the gear 16 connected to the steering shaft 12 rotates in response to the operation of the steering wheel, the swing arm 22 causes the swing arm 22 to pass through the axis P through the gear 18. It swings in the direction of arrow A in FIG. By this swing, the relay rod 28 connected to the swing arm 22 via the arm 30 moves in the axial direction (direction of arrow B in FIG. 2) to steer the steered wheels.

Further, the gear ratio varying power cylinder 32 is operated by the control of the control device in accordance with the running state of the vehicle, for example, the rod 34 is extended, and the tip portion 30B of the arm 30 is fixed to the base portion of the swing arm 22. 22A (FIG. 3), the swing arm 22 and the arm 30
The distance W1 between the engagement position with and the swing fulcrum of the swing arm 22 becomes longer. Therefore, the movement amount of the relay rod 28 with respect to the rotation angle of the steering shaft 12 increases, and the steering gear ratio decreases.

On the other hand, when the rod 34 contracts to bring the tip portion 30B of the arm 30 closer to the base portion 22A of the swing arm 22 (FIG. 4), the swing arm 22 and the arm 3
The distance W2 between the engagement position with 0 and the swing fulcrum of the swing arm 22 becomes shorter. Therefore, the swing arm 22,
That is, the movement amount of the relay rod 28 with respect to the rotation angle of the steering shaft 12 becomes small, and the steering gear ratio becomes large.

Therefore, when the vehicle is traveling at a high speed, the tip portion 30B of the arm 30 is attached to the swing arm 22.
When the vehicle is in a low-speed running state, the steering gear ratio is increased, and the steering gear ratio is increased.
The tip portion 30B of the arm 30 is moved away from the base portion 22A of the swing arm 22 (FIG. 3) to reduce the steering gear ratio.

As a result, in the low speed range, the steering wheel can be steered to the maximum steering angle with a small steering amount of the steering wheel (the steering amount of the steering wheel can be reduced), and garage parking and the like can be facilitated. On the other hand, in the high speed range, since the change in the steering angle of the steered wheels with respect to the steering amount of the steering wheel is small, the steering stability can be ensured. in this way,
It is possible to cover from low speed to high speed with a small amount of steering (angle) without changing the steering wheel.

Further, in the vehicle steering angle ratio variable steering apparatus 10 of the first embodiment, the rotation of the steering shaft 12 is transmitted to the relay rod 28 by the arm 30 which swings in the same direction as the swinging direction of the swing arm 22. In addition, since the engaging position between the arm 30 and the swing arm 22 is moved, the swinging portion of the swinging member can be made smaller and the swinging range can be made smaller than in the conventional technique, so that the device can be downsized. .

Further, in the vehicle steering angle ratio variable steering apparatus 10 of the first embodiment, the steering gear is moved by shifting the engagement position of the arm 30 and the swing arm 22 from the swing center of the swing arm 22 in the radial direction. Since the ratio is changed, the steering neutral position of the steering wheel does not shift due to the change of the steering gear ratio. Therefore, a rudder angle sensor for detecting the neutral position is unnecessary,
Furthermore, complicated control for changing to an appropriate steering gear ratio is not necessary. Further, it is possible to easily configure a fail-safe structure.

In the vehicle steering angle ratio variable steering apparatus 10 of the first embodiment, the gear ratio varying power cylinder 32 is used as the adjusting means, but the adjusting means is not limited to the power cylinder 32, and the arm is not limited. It is only necessary to move 30 in the arrow C direction and the arrow D direction in FIG.

A second steering angle ratio variable steering system for a vehicle according to the present invention.
The embodiment will be described with reference to FIGS.

The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 5, in the vehicle steering angle ratio variable steering apparatus 50 of the second embodiment, the reduction gear 52 as a reduction means can be automatically switched between power steering and manual steering. There is.

Specifically, the power steering pump 5
4 is connected to the gearshift piston 56, and the rod 56A of the gearshift piston 56 is attached to the bracket 58.
Is connected to the moving gear unit 52A of the reduction gear 52 via. The moving gear unit 52A is provided on the steering shaft 1
2 is spline-coupled with each other, and is movable along the axial direction of the steering shaft 12 in the right direction of FIG. 5 (direction of arrow E in FIG. 5) and the left direction of FIG. There is.

Further, the bracket 58 and the rotary valve 1
A coil spring 60 is wound around the outer periphery of the steering shaft 12 between the movable gear unit 52A and the steering shaft 12 and the movable gear unit 52A.
Is urged in the direction of arrow F.

During power steering, the hydraulic pressure of the power steering pump 54 causes the rod 56A of the gear shift piston 56 to move to the right in FIG.

Rod 56A of gear shift piston 56
Moves to the right in FIG. 5, the moving gear unit 52A
Moves in the direction of arrow E, and the gear 62 of the moving gear unit 52A and the gear 63 of the fixed gear unit 52B mesh with each other. The gear ratio at this time is set small.

On the other hand, as shown in FIG. 7, when the moving gear unit 52A moves in the direction of arrow F, the gear 64 of the moving gear unit 52A meshes with the gear 65 of the fixed gear unit 52B. The gear ratio at this time is set to a large value.

As shown in FIG. 5, the power cylinder 32 for varying the gear ratio incorporates a spring 67 for extending the cylinder as a swinging means. Further, the gear ratio changing power cylinder 32 is inserted into a through-hole 66 formed in the shaft 24 along the axial direction, and a pin 68 arranged in a direction intersecting the axial line of the shaft 24 is shown in FIG. Is rotatably supported in the clockwise direction (arrow G in FIG. 5) and the counterclockwise direction in FIG. 5 (arrow H in FIG. 5).

Further, the power cylinder 32 for varying the gear ratio
Is connected to the pump 54 via a solenoid valve 69. The solenoid valve 69 is controlled according to the change in vehicle speed.

Next, the operation of the second embodiment will be described. In the vehicle steering angle ratio variable steering apparatus 50 of the second embodiment, the rod 56 of the gear shift piston 56 is driven by the hydraulic pressure of the power steering pump 54 during power steering.
A moves to the right in FIG. As a result, the moving gear unit 52A moves in the arrow E direction, and the gear 62 and the gear 63 mesh with each other.

When traveling at a high speed, as shown in FIG. 5, a solenoid valve 69 controlled according to a change in vehicle speed.
Due to this, the gear ratio changing power cylinder 32 is contracted. Therefore, the tip portion 30B of the arm 30 approaches the base portion 22A of the swing arm 22, and the steering gear ratio increases.

When the vehicle is traveling at a low speed, as shown in FIG. 6, the solenoid valve 69 is controlled according to the change in the vehicle speed.
Thus, the gear ratio changing power cylinder 32 is extended. Therefore, the tip portion 30B of the arm 30 moves away from the base portion 22A of the swing arm 22, and the steering gear ratio decreases.

On the other hand, for example, when power assist cannot be obtained by the power steering system due to a belt break of the power steering pump 54 (during manual steering), as shown in FIG. 32 is extended by the spring 67. Therefore, the tip portion 30B of the arm 30 moves away from the base portion 22A of the swing arm 22, and the steering gear ratio decreases.

In this state (state of FIG. 7), since power assist cannot be obtained, the coil gear 60 moves the moving gear unit 52A in the arrow F direction. As a result, the gear 64 and the gear 65 having a large gear ratio are
The steering force is reduced because the and are meshed.

Therefore, in the second embodiment, at the time of manual steering, the steering gear ratio becomes smaller and the steering operation can be performed with a comparatively light steering force.

[0045]

According to the variable steering angle ratio steering device for a vehicle of the first aspect of the present invention, an input shaft that rotates in response to a steering operation, an output shaft that is connected to a steered wheel, and a direction that intersects the output shaft. An oscillating means that is rotatably supported around the axis of the oscillating means and oscillates in accordance with the rotation of the input shaft; an arm portion that integrally extends from the output shaft in the radial direction of the output shaft; The engaging position adjusting means for moving the engaging position in the radial direction from the swing center of the swinging means, the steering gear ratio can be changed according to the running state of the vehicle, Moreover, it has an excellent effect that the device can be downsized.

According to a second aspect of the present invention, in the vehicle steering angle ratio variable steering device according to the first aspect, the steering force assist mechanism and the engagement position when the steering force assist mechanism is abnormal are the maximum distance from the swing center. In addition to the effect described in claim 1, there is an excellent effect that the steering gear ratio can be reduced when the power assist system cannot be obtained.

According to a third aspect of the present invention, in the vehicle steering angle ratio variable steering apparatus according to the second aspect, there is provided a deceleration means for decelerating the input from the input shaft in association with the driving means. In addition to the effect described in claim 2, there is an excellent effect that the steering operation can be performed with a comparatively light steering force when the power assist cannot be obtained.

[Brief description of drawings]

FIG. 1 is a side view showing a vehicle steering angle ratio variable steering system according to a first embodiment of the present invention.

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

FIG. 3 is a side view showing the steering angle ratio variable steering device for a vehicle according to the first embodiment of the present invention when the steering gear ratio is small.

FIG. 4 is a side view showing a large steering gear ratio of the vehicle steering angle ratio variable steering apparatus according to the first embodiment of the present invention.

FIG. 5 is a side view showing a steering gear ratio variable steering device for a vehicle according to a second embodiment of the present invention when a steering gear ratio is large.

FIG. 6 is a side view showing a vehicle steering angle ratio variable steering system according to a second embodiment of the present invention when the steering gear ratio is small.

FIG. 7 is a side view showing a state where power assist cannot be obtained in the vehicle steering angle ratio variable steering device according to the second embodiment of the present invention.

FIG. 8 is a schematic plan view showing a conventional steering angle ratio variable steering device according to an embodiment.

[Explanation of symbols]

10 Variable Steering Angle Ratio Steering Device 12 Steering Shaft (Input Shaft) 20 Shaft 22 Swing Arm (Rotating Means) 24 Shaft 26 Groove 28 Relay Rod (Output Shaft) 30 Arm (Arm) 32 Gear Cylinder Variable Power Cylinder (Engagement Position Adjusting Means) 50 Steering Angle Ratio Variable Steering Device for Vehicle 52 Reduction Gear (Reduction Means) 52A Moving Gear Unit 52B Fixed Gear Unit 54 Power Steering Pump 56 Gear Shift Piston 60 Coil Spring 67 Spring

Claims (3)

[Claims] 1. An input shaft that rotates in response to a steering operation, an output shaft that is connected to a steered wheel, and an output shaft that is rotatably supported around an axis line in a direction intersecting with the output shaft and that corresponds to the rotation of the input shaft. The swinging means for swinging, the arm portion integrally extending from the output shaft in the radial direction of the output shaft, and the engagement position between the arm portion and the swinging means are swingable by the swinging means. A steering angle ratio variable steering device for a vehicle, comprising: an engagement position adjusting means that moves in a radial direction from a center. 2. The vehicle according to claim 1, further comprising: a steering force assist mechanism; and a drive unit that sets the engagement position to a maximum distance from a swing center when the steering force assist mechanism is abnormal. Steering angle ratio variable steering device. 3. The variable steering angle ratio steering apparatus for a vehicle according to claim 2, further comprising deceleration means for decelerating an input from the input shaft in association with the driving means.