JPS60135370A - All-wheel-steering gear for vehicle - Google Patents

Abstract

PURPOSE:To keep off any swerve during a driving turn as well as to improve both of turning performance and driving safety, by making rear wheels so as to turn round to a direction increasing the lateral force of tire at deceleration during a car turn. CONSTITUTION:A computer 12 receives a detection signal out of a detection sensor 13 for body's lateral motion such as a lateral acceleration sensor, a yaw rate sensor or the like, and feeds a control signal commensurate to this signal to a servo actuator 8, then performs the rear wheel turn-serrage required. During a car's driving turn, namely, in time of front wheels being turn-steered, if a state of deceleration is the case, it is inputted into the computer 12 which conducts its operational process on the basis of the preset data and makes rear wheels into turn-steerage as far as the specified angle toward where lateral force increases by the operational process of control information, thus a swerve of the car during a driving turn is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a front and rear wheel 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, greatly improving vehicle maneuverability and steering response. Various types of front and rear wheel steering devices have been proposed that can improve performance.

By the way, in general, when the brakes are operated while the vehicle is running and turning, the vehicle speed decreases and the lateral force of the tires decreases, making the vehicle more likely to shake its tail, which may impair running stability.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a front and rear wheel steering system for a vehicle that can effectively prevent oscillation during turning of the vehicle by controlling the steering of the rear wheels and improve running stability during turning. There is something to do.

In order to achieve the above object, the present invention is applied to a front and rear wheel 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 system that detects a deceleration state of the vehicle speed. means for outputting control information necessary for steering the rear wheels in response to the detection result from the detection means; The present invention is characterized by adding means for adding control information to steering information for steering the rear wheels, and steering the rear wheels in a direction in which the lateral force of the tires is fully increased by deceleration during turning.

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 front and rear wheel steering device of a vehicle will be explained based on FIG. This figure is a schematic plan view showing the basic structure of a vehicle equipped with a front and rear wheel steering device according to the present invention. In the figure, reference numeral 1 denotes a steering handle, and the steering shaft 2 of this steering wheel 1 is controlled by a direction change means, for example, a rack and pinion system, which is installed in a gear box 3. converted into movement. Both ends of this tie rod 40 are connected to a knuckle arm 6.6 that supports the front wheels 5, 5, and the displacement of the tie rod 4 in the vehicle width direction is controlled by the function of the knuckle arm 6.6, which is rotatably supported in the left and right direction. , 5 in the steering direction of the steering wheel 1.

On the other hand, 7 is a rear wheel side gear box, and a shaft 8a extending rearward from a rear wheel steering servo actuator 8 is connected to a direction changing means such as a rack and binion type built in this gear box 7. Further, knuckle arms 10, 10 are rotatably connected to both ends of a tie rod 9 which passes through the gear box 7 in a movable manner in the width direction of the vehicle body, and these knuckle arms 10.degree.10 support rear wheels 11.11. As a result, the tie rod 9 is displaced in the width direction of the vehicle body by the rotation of the shaft 8a, similar to the steering of the front wheel side, and furthermore, the rear wheel 11.1
1 in the required steering direction.

On the other hand, the vehicle is equipped with an on-vehicle computer 12, which receives a detection signal from a sensor 13 for detecting lateral movement of the vehicle body, such as a lateral acceleration sensor or a yaw rate sensor, and sends a corresponding control signal to the It is supplied to the rear wheel steering servo actuator 8 to perform necessary rear wheel steering.

Incidentally, reference numeral 14 is a deceleration sensor that detects the vehicle speed or deceleration state by detecting, for example, the rotational speed of the axle, and this will be described later.

As mentioned above, the front and rear wheel steering device shown in Fig. 1 is not directly related to the front wheel steering signal (in the case where the rear wheels are steered by signals related to the behavior of the vehicle body related to front wheel steering, such as yaw rate), Fig. 2 illustrates a case where the rear wheels are steered in relation to the front wheel steering signal.In other words, Fig. 2 shows how the front wheel steering angle detection sensor 15 disposed in the gear box 3 determines the magnitude of the steering wheel angle. By detecting the proportional magnitude of the front wheel steering and providing this detection result to the computer 12, the rear wheels are steered in response to the front wheel steering.
The figure is similar to FIG. 1, and parts that are the same as those in FIG. 1 are given the same reference numerals to clarify the structure and a detailed explanation thereof will be omitted.

Next, the configuration and functions of the main parts of the present invention will be specifically explained with reference to FIGS. 3 to 5. FIG. 3 is a functional block diagram of the rear wheel steering system, and FIGS. 4 and 5 are action explanatory diagrams.

First, in FIG. 3, the computer 12 includes a vehicle body lateral movement detection sensor 13 shown in FIG. 1 or 2;
Alternatively, various sensors such as the front wheel steering angle sensor 15 are connected, and this detection result d1 is processed (b) in the computer 12 based on preset data (a) and corresponds to the detection result d1. rear wheel steering information d2 is obtained. This information d2 is positive when the steering of the rear wheels is in the same phase as the steering of the front wheels, and negative (that is, ±d2) when the steering of the rear wheels is in the opposite phase.

This information d2 is then given to the bore actuator 8, which rotates the shaft 8a and steers the rear wheels 11, 11 through operations such as digital-to-analog conversion, amplification, and motor drive.

The above configuration and functions have already been proposed by the applicant and are the basic technology of the present invention.

On the other hand, the deceleration sensor 14 is connected to the computer 12 as described above, and this deceleration sensor 14 detects the presence or absence of deceleration as well as the magnitude of deceleration, and inputs the detection result d to the computer 12. The computer 12 performs arithmetic processing (e) based on data set in advance.
Required control information d4 corresponding to the detection result d3 is obtained. This control information d4 is added to the rear wheel steering information d2 by the appetizer i addition processing society →, and the servo actuator 8
Informationally, d2+d4 will be supplied to .

Next, the control information pile will be specifically explained. This control information d4 is used to additionally steer the rear wheels by a required angle in a direction that increases the lateral force of the rear wheels, with respect to the steered state of the rear wheels according to the rear wheel steering information d2 while the vehicle is running and turning. As mentioned above, the amount of this additional steering is exactly set in the data.

That is, as shown in FIGS. 4 and 5, the rear wheel steering information d
2, the steering angle of the rear wheels is additionally increased by the steering angle θ or θ2 in the steering direction of the front wheels using the control information d4. Fig. 4 shows a state in which the rear wheels 11.11 are steered in the opposite phase to the front wheels 5, 5, and Fig. 5 shows a state in which they are steered in the same phase. The steered state of the rear wheels after being additionally steered is also shown by the rear wheels 11a, 11a instead of being shown by imaginary lines.

Note that the computer 12 processes the detection results from the front wheel steering angle sensor 15 that detects the magnitude of the front wheel steering angle through the calculation process (
By adding the control information d4 to E), the control information d4 may be added only when the front wheels are being steered, J:')K. Furthermore, the magnitude of the control information d4 can also be changed depending on the magnitude of steering of the front wheels. Furthermore, the magnitude of the control information d4 may be changed depending on the magnitude of the deceleration, that is, the magnitude of the detection result d3.

Therefore, in the computer 12, while the vehicle is running and turning,
If the front wheels are being steered and are in a deceleration state, this is detected and the rear wheels are steered by a predetermined angle in a direction where the lateral force increases, thereby preventing the vehicle from swinging while turning.

In the embodiment, the deceleration sensing sensor 14 is configured with a sensor that directly detects the entire vehicle speed, but it may also be configured with a simple sensor that detects the air pressure. In addition, although all examples are shown in which execution is performed according to a predetermined control program using an on-vehicle computer, an electric circuit having a low-speed function may also be used.

As described above, the front and rear wheel steering device for a vehicle according to the present invention can effectively prevent steering of all rear wheels while the vehicle is running and turning, and can improve turning performance and driving performance during turns. Stability can be dramatically improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view showing the basic structure of a vehicle equipped with a front and rear wheel steering system according to the present invention, Fig. 2 is a schematic plan view of the same in an example of a song, and Fig. 3 is a function of the rear wheel steering system. The block diagram and FIGS. 4 and 5 are action explanatory diagrams. In addition, in the drawing, 11, 11. Ila and 11a are rear wheels, 12 is an in-vehicle computer, 14 is a deceleration sensor, (c) is addition processing, ni) is data, (e)) is arithmetic processing, d2 is rear wheel steering information, and d4 is control information. be. Patent Applicant Honda Motor Co., Ltd. Representative Patent Attorney 1) Yu - Immediate Question Patent Attorney Kuni Ohashi Otoma Patent Attorney Yu Koyama

Claims (1)

[Scope of Claims] A front and rear wheel steering device for a vehicle capable of variably controlling the steering angle of the rear wheels according to certain conditions, characterized in that the front and rear wheel steering device for a vehicle is equipped with the following means (a) for adjusting the vehicle speed. Detection means for detecting all deceleration states, (b) Calculation means for outputting control information necessary to steer the rear wheels to a predetermined steering angle in response to the detection results from the detection means, e→ addition means for adding the control information to the steering information for fully steering the rear wheels so that the steering angle of the rear wheels is steered in the steering direction of the front wheels;