JPS61171666A - Front-rear-wheel steering gear for vehicle - Google Patents

Abstract

PURPOSE:To improve steerability in a car ever so better, by operating a selecting device, which realizes a steering angle ratio corresponding to the information selected from plural numbers of preset steering angle ratio information, only at a time when a car speed variation is within the specified range. CONSTITUTION:The specified steering angle ratio information (d) is stored in a memory of a computer 31. This information (d) consists of plural steering angle ratio data k1, k2...kn. At a select switch 34, when optional buttons other than a pushbutton 35a, for example, a pushbutton 35 is pressed, the steering angle ratio data k1 is read out of the steering angle ratio information (d). This data k1 is compared with steering angle ratio data kb out of a position sensor 33 and both are made into an operation process (f) and thereby corrected information b2 is securable. At a selecting process (c), this corrected information b2 is outputted in a case other than AUTO, whereby a steering angle ratio in the rear wheel is set to the data k1 by way of an output unit 37. At this time, when a car speed variation signal based on a signal out of a car speed sensor 32 is larger than reference car speed variation data (g), the selecting process (c) regulates the output of the said corrected information b2.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a front and rear wheel steering device for a vehicle that can variably control the steering angle of the rear wheels relative to the front wheels.

<Prior Art> The present applicant has already proposed a vehicle steering system (patent application No. 57) that steers the rear wheels in conjunction with the steering of the front wheels and varies the steering angle ratio of the rear wheels to the front wheels in accordance with the vehicle speed. -134888 etc.). To explain the outline of this device, at low speeds, the rear wheels are steered in opposite phase to the front wheels or almost at zero.
On the other hand, at high speeds, the rear wheels are steered in the same phase as the front wheels. As shown by D in Fig. 6, this steering angle ratio becomes a continuous function of the vehicle speed, and if the vehicle speed becomes higher than a predetermined vehicle speed d1 as a boundary, the steering angle ratio becomes positive, that is, in the same phase. As the vehicle speed becomes lower, the steering angle ratio becomes negative, that is, the phase becomes opposite. Continuous control of the steering angle ratio
This is done in accordance with the AD, and allows both the functions of the steering system to be achieved at low and high speeds. As a result, at low speeds, both the minimum turning radius and the difference between the inner wheels of the vehicle are significantly reduced, making it easier to park the vehicle in a garage.
The maneuverability of the vehicle can be dramatically improved when driving on narrow curved roads and knee turns, and on the other hand, the maneuverability can be dramatically improved at high speeds.

By the way, when parallel parking at low speeds or pulling over in a narrow space, if the front wheels and rear wheels are steered in opposite phases, the rear of the vehicle may be swayed laterally, which is inconvenient. In some cases, it may be easier to operate the steering wheel by steering the wheels in the same phase, and even at high speeds, it may be desirable to maintain the steering angle ratio at a constant value according to the driver's preference. Therefore, by providing a manual switching means in such a front and rear wheel steering device, such a demand can be met.

However, depending on the driving situation of the vehicle, when the manual switching means is activated, the steering angle of the rear wheels may change suddenly, and the driver may not necessarily be able to respond appropriately. For example, if the manual switching means switches to a mode in which the rear wheels are in the same phase while accelerating in the opposite phase region, the turning trajectory of the vehicle may suddenly expand, requiring the driver to respond quickly. I will do it.

<Problems to be Solved by the Invention> In view of the above-mentioned problems, the main object of the present invention is to significantly improve the maneuverability of a vehicle by providing a manual switching means. To provide a front and rear wheel steering device for a vehicle in which manual switching is possible only in a state where no sudden change is caused to the motion of the vehicle even if the steering is performed.

Means for Solving the Problems> According to the present invention, such an object is achieved by controlling a preset point in a front and rear wheel steering system of a vehicle that variably controls the steering angle of the rear wheels according to certain conditions. Or a manual that selects two or more pieces of steering angle ratio information or rear wheel turning angle information and the steering angle ratio information or rear wheel turning angle information and realizes the steering angle ratio or rear wheel turning angle corresponding to the selected information. This is achieved by providing a front and rear wheel steering device for a vehicle, comprising a switching means and a regulating means that detects a change in vehicle speed and operates the switching means only when the change in vehicle speed is within a certain range. .

<Effect>
1. In this way, by restricting the operation of the manual switching means when the vehicle is accelerating or decelerating beyond a certain level, inconveniences that may occur due to sudden changes in the steering angle of the rear wheels are avoided. can do.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the drawings, Fig. 1 is a perspective view showing the general basic structure of a vehicle equipped with a front and rear wheel steering system, Fig. 2 is an enlarged perspective view of the rear wheel steering system, and Figs. 3 (a), (b) and ((l is a cutaway side view showing the principle of operation.

First, in order to clarify the present invention, the configuration and operation of the front and rear wheel steering device will be explained with reference to FIGS. 1 to 3.

The handle shaft 2 of the handle 1 is incorporated into a rack and pinion gear box 3, and tie rods 5.5 are connected to the left and right ends of the rack shaft 4, and a front wheel 7.7 is supported at the outer ends of both tie rods 5.5. A knuckle arm 6.6 is connected thereto, and the front wheels 7.7 are steered in the steering direction of the steering wheel 1, as is known.

On the other hand, a rear hennion shaft 8 is led out from the gear 7 box 3, and a long linkage shaft 10 is connected to the rear end of this shaft 8 via a universal joint 9.

An input shaft 12 is connected to the rear end of the linkage shaft 10 via a universal joint 11, and this input shaft 12 is arranged on the left-right center line of the rear part of the heavy object, and is rotatably supported by a bearing bracket 13. There is.

Further, a swing shaft 15 shown in detail in FIG. 2 is connected to the rear end of the input shaft 12 via a clevis 14, and a joint member 16 is loosely fitted in the middle of the swing shaft 15. Tie rods 18.18 are connected to the left and right ends of the joint member 16 via ball joints 17.17, and the joint member 16 is swingably supported on the vehicle body side by links 21.22 and brackets 23. . Also, both tie rods 1
A knuckle arm 19.19 supporting a rear wheel 20.20 is connected to the outer end of 8.18.

An arm 25 is fixed to the rear end of the swing shaft 15 so as to protrude downward, and a link 2d is pivotally connected to the lower end of the arm 25 so as to be freely rotatable in the vertical direction.
A slider 27 is similarly pivotally mounted to the rear end of the slider 6 so as to be freely rotatable in the vertical direction.

An output shaft 30 of a motor 29 is screwed onto the slider 28 via a ball screw mechanism 28 as shown in FIG. is fixed to the vehicle body.

On the other hand, the vehicle is equipped with an on-board computer 31, which receives signals from a heavy speed sensor 32 that detects the vehicle speed and a position sensor 33 that detects the position of the slider 27, and performs appropriate control according to the vehicle speed. signal to motor 2
Supply to 9.

When the slider 27 is in the position shown in FIG. 3(a) and the pivot point P of the joint member 16 coincides with the axis of the input shaft 12, the input shaft 12 and the swing @15 are concentric. Due to the rotation, the joint member 16 does not swing from side to side, and the tie rods 18, 18 also remain stationary. Therefore, only the front wheels 7.7 are steered and the rear wheels 20.20 are not steered at all.

On the other hand, when the vehicle speed is lower than the set value d1 (Fig. 6),
The computer 31 drives the motor 29 in response to the vehicle speed signal from the vehicle speed sensor 32, thereby positioning the slider 27 at the forward position as shown in FIG. 3(b). When the slider 27 is in the forward position, the swing shaft 15 tilts downward,
Since the pivot point P is offset (if center) by e below the axis of the input shaft 12, the joint member 16 swings left and right in accordance with the rotation of the input shaft 12, and the rear wheel tie rod 18. Displace the front wheel tie rod 5.5 in the opposite direction. Therefore, the rear wheels 20.2o are steered in a phase opposite to that of the front wheels 7.7, and the steering angle ratio of the front and rear wheels changes continuously in accordance with the vehicle speed.

When the vehicle speed exceeds the set value d1 (FIG. 6), the computer 31 reverses the motor 29 in accordance with the vehicle speed at that time, and moves the slider 27 backward as shown in FIG. 3(C). As the slider 27 retreats, the swing shaft 15
is tilted upward, and the pivot point P is offset upward by 02 from the axis of the input shaft 12, so the joint member 1
6 is an input shaft; 2. ). a &: U Eka O Swing 5.9. □
,stomach ! 10. Displace the tie rod 18.18 in the same direction as the front wheel tie rod 5.5. Therefore, the rear wheels 20.20 are steered in the same phase as the front wheels 7.7, and the steering angle ratio of the front and rear wheels also changes continuously in accordance with the vehicle speed.

Next, the main structure of the present invention will be explained with reference to FIGS. 4 to 6. FIG. 4 is a configuration diagram of main parts, FIG. 5 is a functional block diagram of FIG. 4, and FIG. 6 is a steering angle ratio output characteristic diagram in FIG. 5.

First, in FIG. 4, reference numeral 34 indicates, for example, a plurality of push buttons 3.
5a135b... is a steering angle ratio (or rear wheel steering angle, the same hereinafter) manual selection switch configured by arranging
It is arranged on an instrument panel 36 inside the vehicle so that the driver can manually operate it. This selection switch 34 is connected to the computer 31, and the selection result of the steering angle ratio selected by the selection switch 34 is input to the computer 31.

Next, in the computer 31, referring to FIG.

The following describes the manual selection function of the steering angle ratio.

First, the normal operation (auto operation) in which the steering angle ratio automatically changes depending on the vehicle speed will be explained. This is selected by pressing the first push button 35a of the selection switch 34. As described above, the medium speed signal detected by the vehicle speed sensor 32 is input to the computer 31, and is converted by the conversion process (a) into the steering angle ratio de-rika corresponding to the vehicle speed.

On the other hand, the actual steering angle ratio data is obtained from the position sensor 33, and both steering angle ratio data kk are compared and processed (0) to obtain necessary steering angle ratio correction information b1. On the other hand, since the auto operation A1 is selected in the selection switch f34, the correction information b1 is output as is from the computer 31 in the selection process (c), and the correction information b1 is outputted as is according to the vehicle speed via the output device 37. The correction Ill/tll signal S1 for changing the steering angle ratio to the motor 2
9.

On the other hand, predetermined steering angle ratio information (d) is stored in the storage device of the computer 31. This information (d) is, for example, 1, k2, k3 for multiple pieces of steering angle ratio data having arbitrary sizes.
,...consists of ko. Then, in the selection switch 34, if you press any push button other than the push button 35a, for example, the hold button 35b, 1 is read out from the steering angle ratio information (d) as the steering angle ratio data, which indicates the position. The steering angle ratio data from the sensor 33 is subjected to comparison processing (e) and correction information b.
2 is obtained.

17j. In the selection process (c), if a push button other than ○ for automatic operation in the selection switch 34 is pressed, in response to this, the output of the correction information b1 is stopped, and the output of the correction information b1 is stopped. Select to output correction information b2. As a result, the modified control signal S2 is supplied from the output device 37 to the motor 29, and the steering angle ratio of the rear wheels is set to 1.

This operation is the same for the other pushbuttons 35b, 35a..., and the driver manually selects any steering angle ratio k1, k3...kn shown in FIG. 6 using the selection switch 34. be able to.

On the other hand, the computer 31 differentiates the vehicle speed signal from the vehicle speed sensor J32 to obtain a (h) vehicle speed change signal, and executes the determination process (h). In this judgment process,
The vehicle speed change signal is compared with preset reference vehicle speed change data (g), and it is determined whether or not it is greater than the M quasi-vehicle speed data (g). If the change in heavy speed is large, that is, if the change in vehicle speed exceeds a constant speed change value, the judgment result is given to the selection process (c), and the output of correction information b2 for manual correction is regulated.

In other words, when the steering angle ratio is being corrected using the automatic operation wJA□, if the vehicle speed change exceeds the constant speed change, even if an attempt is made to make manual correction using the manual selection switch 34, the selection process (H ) is made by auto 11
1JA, and do not shift to manual operation.

In addition, the above vehicle speed change data (g) that enforces such regulations
is selected by considering speed changes that do not cause sudden changes in the vehicle motion state. In general, this vehicle speed change data can be determined so as to be compared with the absolute value of the heavy speed change, but it is possible to set different limit values for acceleration and deceleration'''+tt, -rtt* for acceleration and deceleration, respectively. ′″″1°”Cf
f-6ri6 Z"6-6・11 and above computer 3
Various processes in 1 may be executed by a predetermined control program (software) stored in, for example, a storage device in the computer 31.

Although the on-vehicle computer 31 is used in the above embodiment, an electrical circuit or mechanical configuration having other functions may be used.

Furthermore, although the steering angle ratio of the front and rear wheels can be manually selected using the position sensor 33 and the manual selection switch 34, the steering angle of the rear wheels may also be selected in the same manner.

Furthermore, the present invention is not limited to the embodiments, and may include a front and rear wheel steering device that hydraulically controls front and rear wheels and transmits heavy wheel steering angle information using hydraulic pressure, or a front and rear wheel steering device that transmits front wheel steering angle information to a computer 31 as an electrical signal. The present invention can be similarly applied to front and rear wheel steering devices, etc.

Furthermore, by providing suitable delay means in the manual switching means, manual selection is achieved gradually, even if the operation of the manual switching means is not regulated, so that the steering angle of the front wheels remains constant in all cases. The steering angle of the rear wheels may be prevented from changing suddenly regardless of the situation.

<Effect> As described above, according to the present invention, a desired steering angle ratio can be set regardless of the vehicle speed, etc. in a vehicle front and rear wheel steering device, etc., which can vary the steering angle ratio of the rear wheels to the front wheels according to the vehicle speed, etc. By being able to make manual changes at will, it improves the maneuverability of the vehicle, and also prevents manual selection when manual operation is not required, thereby preventing sudden changes in the vehicle's motion state that are unexpected by the driver. There is.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the general basic structure of a vehicle equipped with a front and rear wheel steering device. FIG. 2 is an enlarged perspective view of the rear wheel steering system. FIGS. 3(a), 3(b), and 3(C) are cutaway side views showing the operating principle of the rear wheel steering system. FIG. 4 is a configuration diagram of the main parts. FIG. 5 is a functional block diagram of FIG. 4. FIG. 6 is a steering angle ratio output characteristic diagram in FIG. 5. 1... Handle 2... Handle shaft 3...
Gear box 4...Rack shaft 5...Tie rod 6...Knuckle arm 7...Front wheel
8... Pinion shaft 9... Universal joint 10.
... Linkage shaft 11 ... Universal joint 12 ...
Input shaft 13...bearing bracket 14...clevis 1
5... Swing shaft 16... Joint member 17
...Ball joint 18...Tie rod 19...
Knuckle arm 20...Rear wheel 21.22...Link 23...Bracket 25...Arm 26
... Link 27 ... Slider 28 ... Pole screw mechanism 29 ... Motor 30 ... Output shaft 31 ...
Computer 32...Vehicle speed sensor 33...Position sensor 34...Selection switches 35a to 35d...
Push button 37...Output device patent applicant Honda Motor Co., Ltd.
Attorney Patent Attorney Yo Oshima
-Second! ! 1 Figure 3 (a) l mouth (b) (c) Figure 4 Figure 6 (i!! phase)

Claims (1)

[Scope of Claims] A front and rear wheel steering device for a vehicle that variably controls the steering angle of the rear wheels according to certain conditions includes one or more preset steering angle ratio information or rear wheel steering angle information; A manual switching means that selects the steering angle ratio information or rear wheel steering angle information and realizes the steering angle ratio or rear wheel steering angle corresponding to the selected information; and a manual switching means that detects a change in vehicle speed and keeps the vehicle speed change within a certain range. A front and rear wheel steering device for a vehicle, comprising: a regulating means that operates the switching means only when the switching means is operated.