JPS60135371A - All-wheel-steering gear for vehicle - Google Patents

Abstract

PURPOSE:To make a driver easily frontward ahead a corber, by making an all- wheel-steering gear so as to change a car body attitude in order to cause it turn to the inner side of a turning direction when the car accelerates at the latter half cornering. 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 rear wheel steering survo actuator 8, performing the rear wheel turning steerage required. If a car is in a state of acceleration when front wheels are turn- steered, it is detected by an acceleration sensor 14 and data d3 is inputted into the computer. Inside the computer 12, an operational process (e) takes place on the basis of the front data (d) whereby control information d4 is secured. And, it is subtracted from rear wheel turn-steerage information d2 by a subtraction process, and (+ or -d2-d4) is fed to the servo actuator 8 and thereby a car body attitude is made to be headed toward the inner side of a turning direction.

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, dramatically improving vehicle maneuverability and steering response. Various types of front and rear wheel steering devices have been proposed that have been improved to improve the steering angle.

By the way, when a vehicle is turning (cornering), it is common for the driver to accelerate in the latter half of the cornering, but in this case, in curves with relatively poor visibility, it is better for the vehicle body to face inward in the direction of the turn to see what is ahead of the corner. I can see through it.
Therefore, the object of the present invention is to control the steering of the rear wheels during the latter half of cornering while the vehicle is running around a curve, etc., thereby changing the attitude of the vehicle body. The driver can see clearly all the way to the front of the corner.
To provide a front and rear wheel steering device for a vehicle that allows easy visibility and allows comfortable driving even on curves with poor visibility.

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 components are
vV control means, a calculation means for outputting control information necessary to steer the rear wheels to a predetermined steering angle in response to the detection result from the first detection stage, and a steering angle of the rear wheels. The control information is subtracted from the steering information for steering the rear wheels so that the steering direction is opposite to the steering direction of the front wheels. It is characterized by controlled rear wheels.

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. The steering rotation of the steering wheel 1 is converted into a movement of the tie rod 4 in the width direction of the vehicle body by means of an internal direction changing means, for example, a rack and pinion type. Both ends of this tie rod 4 are knuckle arms 6 that support the front wheels 5, 5.
．． Due to the function of the knuckle arm 6.6 which is connected to 6 and supported rotatably in the left and right direction, the displacement of the tie rod 40 in the width direction of the vehicle body causes the front wheels 5, 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 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 pinion type built in this gear box 7. Further, knuckle arms io and i are provided at both ends of a tie rod 90 that passes through the gear box 7 so as to be movable in the width direction of the vehicle body.

These knuckle arms 10°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 wheels, and the ``rear wheels'' l i, ii are further steered in the desired steering direction.

On the other hand, the vehicle is equipped with an on-board 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 yaw rate sensor, and outputs a corresponding control signal. It is supplied to the rear wheel steering servo actuator 8 to perform necessary rear wheel steering. Note that reference numeral 14 is an acceleration sensor that detects that the vehicle speed is in an accelerated state, 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 a signal related to the behavior of the vehicle body related to front wheel steering, such as yaw rate, The figure shows an example in which the rear wheels are steered in relation to the front wheel steered signal.In other words, in FIG. By detecting the magnitude of the front wheel steering operation and providing this detection result to the computer 12, the rear wheels are steered in response to the front wheel steering.
FIG. 2 is a diagram similar to FIG. 1, and the same parts as in FIG. 1 are denoted by the same reference numerals to clarify the structure and omit detailed explanation thereof.

Next, the configuration and functions of the main parts of the present invention will be specifically explained with reference to FIGS. 3 to 6. FIG. 3 is a functional block diagram of the rear wheel steering system, and FIGS. 4 to 6 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 d is subjected to arithmetic processing (o) in the computer 12 based on preset data (a). Rear wheel steering information d2 is obtained. This information d 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 applied to the servo 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 acceleration sensing sensor 14 is connected to the computer 12 as described above, and the sensor 14 detects the presence or absence of acceleration as well as the magnitude of acceleration, and inputs this detection result d3 to the computer 12. Then, calculation processing (e) is performed based on the data set in advance) to obtain required control information d4 corresponding to the detection result d3. Then, this control information d4 is subtracted from the rear wheel steering information d2 by the current subtraction process, and information (±d2-d4) is supplied to the servo actuator 8.

Next, the control information d4 will be specifically explained. This control information d4 changes the attitude of the vehicle body toward the inner side in the turning direction in response to the steered state of the rear wheels according to the rear wheel steering information d2 while the vehicle is turning. This is to additionally steer the rear wheels in the opposite direction to the steering direction of the front wheels by a required angle, and as mentioned above, the magnitude of this additional steering is determined by the data. .

That is, as shown in FIGS. 4 and 5, the rear wheel steering information d
For the rear wheels 11.11 shown by solid lines originally set by 2, the steering angle of the rear wheels is additionally changed by the steering angle θ1 or θ2 in the opposite direction to the steering direction of the front wheels using the control information d4. Figure 4 shows the rear wheel 11.
．． 11 shows a state in which the front wheels are steered in an opposite phase to the front wheels 5°5, and FIG. 5 shows a state in which they are steered in the same phase, both of which show the rear wheels after being additionally steered The steering state of the vehicle is shown by the rear wheels 11a, 11a indicated 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 reduced only when the front wheels are being steered. 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 acceleration, that is, the magnitude of the detection result d3.

In the yacht and computer 12, while the vehicle is running and turning,
In other words, if the front wheels are being steered and are in an acceleration state, this is detected and the rear wheels are steered by a predetermined angle so that the attitude of the vehicle body is additionally directed inward in the direction of the turn, for example during the latter half of cornering. This allows the driver to easily see what's ahead. 6(a) and 6(c) show a state in which the vehicle C is traveling on a curve E, FIG. 6(a) shows the vehicle body posture with the conventional steering system, and FIG. The figure shows a state in which the attitude of the vehicle body is changed according to the front and rear wheel steering system.It is clear from the figure that with the conventional 51C1 steering system, the driver cannot see ahead of the corner as shown by the arrow (Hl). According to the front and rear wheel steering system according to the present invention, the driver can easily and clearly see ahead of the corner as shown by the arrow (H2).

In the embodiment, the acceleration sensing sensor 14 is configured with a sensor that directly detects the vehicle speed, but it may also be configured with a simple sensor that detects the accelerator pressing force or the like. Moreover, although the case where execution is performed according to a predetermined control program using an on-vehicle computer is illustrated, an electric circuit having the ground function may also be used.

As described above, the front and rear wheel steering device for a vehicle according to the present invention changes the attitude of the vehicle body so that it faces inward in the turning direction when the vehicle accelerates in the latter half of cornering while driving around a curve. The driver can easily and clearly see ahead of the corner, allowing comfortable driving even on curves with poor visibility.

[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 another example of the same, and Fig. 3 is a function of the rear wheel steering system. The block diagram and FIGS. 4 to 6 are action explanatory views.
14 is an on-vehicle computer, 14 is an acceleration sensor, (c) is a subtraction process, (d) is data, (e) is an arithmetic process, d2 is rear wheel steering information, and d4 is control information. Patent applicant Honda Motor Co., Ltd. agent Patent attorney 2 1) Yong - 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 by comprising the following means. (a) Detection means for detecting an acceleration state of vehicle speed; (b) Outputting control information necessary for steering the equipped wheels to a predetermined turning angle in response to the detection result from the detection means. (c) subtraction means for subtracting the control information from the steering information for steering the rear wheels so that the steering angle of the rear wheels is steered in a direction opposite to the steering direction of the front wheels;