JPS60148771A - Steering device for vehicles - Google Patents

Abstract

PURPOSE:To make stable steering wheel operation performable all the time even in a turning drive, by controlling rear wheels for their turn-steering according to a detection value of tire inflation pressure, in case of a steering device which makes a turn-steering angle for these rear wheels controllable. CONSTITUTION:In case of a device which operates rear wheel turn-steering information d0 at a computer 12 in which each output signal out of a lateral acceleration sensor 13 and a front wheel turn-steering angle sensor 14, etc., is inputted, and turns and steers rear wheels 11 through a servo actuator 8 according to the operation result, the required control information d1 on rear wheel turn- steering is secured on the basis of each detection signal out of each of inflation pressure sensors 15-18 installed in each of front and rear wheels 5 and 11. Then, this control information d1 is added or subtracted to or from the said rear wheel turn-steering information d0, and the control information of (d0+d1) or (d0-d1) is fed to the said actuator 8, controlling the turn-steering of rear wheels. That is to say, for example, when the tire inflation pressure becomes smaller than the reference value, each rear wheel is turn-steered as far as the specified angle in a turn-steering direction of each front wheel 5.

Description

[Detailed description of the invention] The present invention relates to a steering device for a vehicle such as a four-wheeled vehicle. .

The present applicant has already steered not only the front wheels of a vehicle but also the rear wheels depending on certain conditions such as vehicle speed and front wheel steering angle, dramatically improving vehicle maneuverability and steering response. Improvement・
A steering system for a vehicle that can
No. 888, etc.).・ □ By the way, in general, when a vehicle turns, the amount of cornering power that acts on the tires of each wheel has a large effect on turning performance. This cornering power is expressed as the rate of increase in lateral force with respect to changes in tire sideslip angle, and varies depending on various conditions such as tire air pressure, ground contact load, and road surface conditions.

In other words, when the air pressure of the tires decreases, or when the ground load of the tires increases due to loaded cargo, etc., cornering power decreases, and especially when the cornering power of the rear tires decreases, the vehicle body during turns This makes it easier for the driver to swing his butt, reducing turning performance and making it difficult for the driver to operate the steering wheel stably.

On the other hand, if the cornering power of the rear tires increases, on the other hand, the vehicle will have a stronger tendency to understeer, and for example, it will become difficult to turn the vehicle while cornering at medium speeds, reducing turning performance and forcing the driver to steer the vehicle less easily. needs to be larger than normal. In this case, if the rear wheels are steered in a direction that reduces such adverse effects, the adverse effects can be effectively eliminated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle steering system that can always perform stable / It is in.

Another object of the present invention is to detect cornering power by detecting tire air pressure which can approximately approximate cornering power, thereby making it simple and inexpensive.+lj 1.1
4 steering devices are provided.

In order to achieve the above object, the present invention is applied to a steering system for a vehicle that can variably control the steering angle of the rear wheels according to certain conditions, and its main component is a detection means for detecting the air pressure of the tires of the vehicle. and processing means for outputting control information for steering the rear wheels in response to the detection result from the detection means, and processing means for additionally steering the rear wheels by a predetermined steering angle based on the control information. By detecting the air pressure of the tire, for example, when the tire air pressure becomes larger or smaller than the reference setting value during cornering, the air pressure is adjusted to the reference setting value. It is characterized by the fact that the wheels are steered.

Below, preferred embodiments that further embody the present invention will be described in detail with reference to the drawings.

First, in order to clarify the present invention, a schematic configuration of a vehicle steering system will be explained based on FIG. This figure is a schematic plan view showing the basic structure of a vehicle equipped with a steering device according to the present invention. In the same figure (re is the steering wheel,
This handle (1) (7) steering shaft (2) is connected to a steering gear mechanism, for example, a rack and pinion system, which is installed inside the gear box (3).
) is converted into a movement of the tie rod (4) in the vehicle width direction. Both ends of this tie rod (4) are connected to the front wheel (5).
), (5) supporting knuckle arm (S), (8
) is connected to the tie rod (4
) in the vehicle width direction causes the front wheels (5) and (5) to be steered in the steering direction of the steering wheel (1).

On the other hand, (7) is a rear wheel side gear box, and the direction changing means such as a rack and pinion system installed in this gear box (7) has a shaft (8) extending rearward from the rear wheel steering servo actuator (8). Connect 8a). In addition, knuckle arms (lO), (lO) are rotatably connected to both ends of a tie rod (9) that passes through the gear box (7) in a movable manner in the width direction of the vehicle body. , (10) is the rear wheel (11), (11)
support. This allows the shaft (
The rotation of 8a) displaces the tie rod (9) in the width direction of the vehicle body, and further steers the rear wheels (11) in a desired direction.

On the other hand, the vehicle is equipped with an on-board computer (12), and this computer (!2) is, for example, a lateral acceleration sensor (or yaw rate sensor) that detects the acceleration of the vehicle in the lateral direction.
(13) receives detection signals from a front wheel steering angle sensor (14) that detects a change in the steering angle of the front wheels, a vehicle speed sensor that detects the vehicle speed indicated by the efficiency diagram, and transmits a corresponding control signal to the rear wheels. It is supplied to a steering servo actuator (8) to control necessary rear wheel steering, for example, in the same phase direction at high speeds and in the opposite phase direction at low speeds.

In addition, each front wheel (5), (5), and each rear wheel (11
) and (11) each include an air pressure sensor (for example, using a pressure-sensitive element, etc.) that detects the air pressure of each tire according to the present invention.
15), (1B), (1?), (1B), and these air pressure sensors (15), (16), (17), (18)
is connected to the computer (12).

Next, the configuration and functions of the main parts of the present invention will be specifically explained with reference to FIGS. 2 and 3. FIG. 2 is a functional block diagram of the rear wheel steering system, and FIG. 3 is an explanatory diagram of its operation.

First, in FIG. 2, the computer (12) has a first
Various sensors such as the lateral acceleration sensor (!3) shown in the figure or the front wheel steering angle sensor (14) are connected, and the detection results are stored in the computer (12) using preset data ( Arithmetic processing (b) is performed based on (a) to obtain rear wheel steering information (dO) corresponding to the detection result. This information (do
) is applied to the servo actuator (8), for example by digital-to-analog conversion, amplification, motor drive, etc., or by operation of mechanical means such as a hydraulic cylinder, etc., to drive the shaft (8a).
Zero or more configurations and functions for rotating the rear wheels (11) and steering the rear wheels (11) have already been proposed by the applicant and are the prerequisite technology of the present invention.

On the other hand, in the computer (12), the detection signals (SO) detected from the air pressure sensors (15), (18), (1?), (18) are later detailed based on preset data (d). The arithmetic processing (e) described above is performed, and the detection signal (So
) to obtain 11+Hoya mountain control information (dl) and add or subtract it from the rear wheel steering information (do) according to (c), and send the information (dO-1dl) to the servo actuator (8).
or (do-dl).

Next, the above calculation process (e) will be specifically explained. As mentioned above, when tire pressure decreases, cornering power decreases accordingly. therefore,
When the tire air pressure detected by the air pressure sensor becomes smaller than a preset reference value, the front wheels are further steered in accordance with the rear wheel steering information (dO). in the rudder direction (same phase direction)
In other words, as shown in Figure 3, the rear wheels (11) and (11) shown by solid lines are steered to the rear wheels (lla) and (lla) shown by imaginary lines. The magnitude of the additional steering angle is selected to be such that the steering angle of the entire rear wheels prevents the vehicle body from swinging by 1, and data (d) is generated. Settings are memorized.

On the other hand, when the air pressure becomes larger than the set value, the front wheel steering direction is reversed (inverse phase direction) with respect to the rear wheel steering state based on the rear wheel steering information (dO). ) is additionally steered by a predetermined steering angle. In other words, the rear wheels (11) and (11> shown by solid lines as shown in Fig. 3)
However, the steering angle information (dl) for steering the rear wheels (1tb) and (Hb) shown by virtual lines is generated. The size was selected so that 11 trajectories could be obtained, and the data (
d) and shi7, ゛It is stored. ,.

In this case, in the case of the former, addition/subtraction) processing) (“I, to)
In □, it becomes addition processing, and in the case of the master (± voice calculation processing,
Note that tire air pressure is detected for the front and rear tires, respectively, and the detected results are calculated, and these are combined in a matrix to create optimal control information. In this case, it is possible to simply adjust the air pressure of only the rear tires.

Since the magnitude of the difference varies depending on the ground contact load, by detecting the ground contact load, this detection result is sent to the □ computer (12) and is sent in parallel with the tire air pressure detection result obtained as described above. It is also possible to generate control information in combination to improve control reliability.

Therefore, the computer (12) detects the air pressure of the tires when the vehicle is making a turning turn: middle or 9th turn, and when the wheel is turned and turns 5 degrees, and calculates the cornering power.
−． 0 or more computer controls (12) that can additionally control the rear wheel steering angle by Each process is executed according to a control program (software) stored in memory in advance.In addition, there is also a circuit such as 1 that has the same function instead of the computer (12). As such, in the vehicle steering system according to the present invention, the vehicle running is adversely affected by changes in tire air pressure, that is, changes in cornering force.
, you can always perform stable l\ndle operation even when the swivel operator is on the move,
The cornering performance can be improved, and since the cornering power can be detected only by detecting the tire air pressure, which can approximately approximate the cornering power, the configuration can be simple and inexpensive.

[Brief explanation of drawings]

ptS1 is a schematic plan view showing the basic structure of a vehicle equipped with a steering device according to the present invention, FIG. 2 is a functional block diagram of a rear wheel steering system, and FIG. 3 is an explanatory diagram of the operation. In addition, (11), (11), (lla), (l
la) (llb), (llb) is the rear wheel, (12) is the on-board computer (15), (18), (17), (1
B) is the air pressure sensor, (a) and (d) are data, (b) and (e) are arithmetic processing, (c) is addition and subtraction processing, (dO)
is rear wheel steering information, and (di) is control information. Patent Applicant Honda Motor Co., Ltd. Agent Patent Attorney 2 1) Yu-Buma Patent Attorney Kuni Ohashi Production Volume Patent Attorney Yu Koyama

Claims (3)

[Claims] (1) A vehicle steering device capable of variable control of the steering angle of rear wheels according to a fixed condition, characterized by comprising the following means. (b) Detection means for detecting tire air pressure; (b) Processing means for outputting control information for steering the rear wheels in response to the detection result from the detection means; (c) control means for controlling the steering of the (2) The processing means outputs control information for steering the rear wheels by a predetermined steering angle in the steering direction of the front wheels (in the same phase direction) when the tire air pressure becomes smaller than the reference setting value. A steering device for a vehicle according to claim 1. (3) When the tire air pressure becomes higher than the reference setting value, the processing means steers the rear wheels by a predetermined steering angle in a direction opposite to the steering direction of the front wheels (in an opposite phase direction). 2. The vehicle steering device according to claim 1, wherein the vehicle steering device outputs control information for controlling the vehicle.