JPS6085071A - Vehicle front and rear wheel steering device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a front and rear wheel steering system for a vehicle capable of fully variable control of the steering angle of the rear wheels relative to the front wheels.

The present applicant has already proposed a vehicle steering system 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 according to the vehicle speed (Japanese Patent Application No. 134888/1988, etc.)' lf: Suggested. An overview of this device will be explained. At low speeds, the rear wheels are steered in the opposite phase to the front wheels, or almost to zero, while at high speeds, on the contrary, the rear wheels are steered in the same phase as the front wheels. The steering angle ratio is a continuous function of the vehicle speed, as shown by D in FIG.
As the t4 boundary, if the vehicle speed is higher than this, the steering angle ratio is positive.
In other words, if the vehicle speed is lower than this, the steering angle ratio becomes negative, that is, the phase is opposite, and the steering angle ratio is continuously controlled according to this function @D, and the steering system functions at low speeds and high speeds. Both are compatible. This significantly reduces both the vehicle's minimum turning radius and the difference between the inner wheels at low speeds, dramatically improving the maneuverability of the vehicle when entering a garage, driving on narrow curved roads, knee turns, etc. On the other hand,
At high speeds, maneuvering responsiveness can be dramatically improved.

By the way, when performing parallel parking at low speeds or pulling closer in a narrow space, it is often easier to steer the vehicle if the front and rear wheels are steered in the same phase rather than in opposite phases.

Therefore, an object of the present invention is to be able to arbitrarily change the steering angle ratio (or steering angle) of the rear wheels to the front wheels, regardless of the vehicle speed or the amount of front wheel turning. This prevents unnecessary steering wheel operations due to temporary fluctuations in the amount of rear wheel steering that occurs, and allows arbitrary changes only when manual operation is necessary, such as at extremely low speeds when parallel parking.
To provide a front and rear wheel steering device for a vehicle that can greatly improve maneuverability of the vehicle.

In order to achieve the above object, the present invention is applied to a front and rear wheel steering system for a vehicle that variably controls the steering angle of the rear wheels according to certain conditions, and its main components are set in advance in an on-board computer, etc. A manual switching means consisting of steering angle ratio (or rear wheel steering angle) information of 1 or 2 or more, an external selection switch for selecting this steering angle ratio (or rear wheel steering angle) information, and a lever position of a gear shift lever. and a regulating means for detecting and operating the switching means only when in a low speed gear position, and using the switching means to optionally change the steering angle ratio (or rear wheel steering angle) only at extremely low speeds that require manual setting. It is characterized by being able to do the following.

Below, preferred embodiments that further embody the present invention will be described in detail with reference to the 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 Fig. 3 (at, (B and (cl) is a cutaway side view showing the principle of operation thereof.

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 assembled into a rack and pinion type gear box 3, and tie rods 5, 5 are connected to the left and right ends of the rack shaft 4.
) A knuckle arm 6.6 supported by the 11th wheel 7.7 is connected, and as is known, the front wheels 7, 7 are operated by the handlebar 1.
The vehicle is steered toward the IC direction.

On the other hand, from the gear box 3 to the 4i direction Binyon River 1
18 is derived, and after this axis 8 11111: j'iT
ν: 1 self-right navy blue [Long linkage shaft 10 through D-9]
are concatenated.

After the linkage shaft 10 ψ11); vC is connected to an input shaft 12 via a universal joint 11, and this input shaft 12 is arranged on the left-right center line of the rear part of the vehicle body, and is rotatably supported by a bearing bracket 13. input shaft 1
A swing shaft 15 shown in detail in FIG. 2 is connected to the rear end of the swing shaft L1 via a universal joint 14. A joint member 16 is loosely fitted in the middle of the swing shaft 15. A tie rod 18°18 is connected to the left and right ends of the joint portion 4g'16 via a ball joint 17.17, and the joint member 16
is swingably supported on the vehicle body side by links 21, 22 and a bracket 23. Also, both Tyrones 18.1
Knuckle arms 19, 19 supporting rear wheels 20, 20 are connected to the outer ends of the wheels 8.

Then, after An + lI + 15 M: A: Ic
An arm 25 is fixed perpendicularly to the axis, and this arm 25
A link 26 is pivotally attached to the lower end of the link 26, and a sliter 21 is pivotally attached to the rear end of the link 26. This slider 27
As shown in FIG. 3, the output shaft 30 of the motor 29 is screwed together via the ball screw mechanism 28, and the output shaft 30 is coaxial with the input shaft 12 and arranged at the rear, thereby fixing the motor 29 to the vehicle body. .

On the other hand, the vehicle is equipped with an on-board computer 31'f, which receives signals from a vehicle speed sensor 32 that detects the entire vehicle speed and a position sensor 33 that detects the position of the slider 27, and performs appropriate control according to the vehicle speed. A signal is supplied to the motor 29.

Therefore, the slider 27 is located at the position shown in FIG.
input shaft 12 and swing shaft 15.
Since the joint member 16 rotates concentrically with the joint member 16, the joint member 16 does not swing from side to side, and the tie rods 18 and 18 also remain stationary. Therefore, only the front wheels 7,1 are steered and the rear wheels 20,20 are not steered at all.

On the other hand, when the vehicle speed is low (lower than the set value), the computer 3
1 receives a signal from the vehicle speed sensor 32, and controls the rotation of the motor 29 according to the vehicle speed at that time.
), move the slider 27 forward. As the slider 27 moves forward, the swing shaft 15 tilts downward, and the pivot point P is offset (eccentrically) in the T direction from the axis of the input shaft 12, so the joint ground phase 16 swings left and right.
Tie rod 18.18 for the rear wheel and Tilerad 5,5 for the front wheel
The rear wheel 20.20 is moved in the opposite direction to the front wheel 7.
, 7 is steered in the opposite phase. At this time, the steering angle ratio Q of the front and rear wheels
It changes continuously depending on the vehicle speed.

Okay, when the vehicle speed exceeds the set value, computer 3
1 is the motor 29f: reverses the rotation according to the vehicle speed at that time,
The slider 27 is moved backward as shown in FIG.
The pivot point P is set 02 above the axis of the input shaft 12, and the rear wheel tie rod 18.18 is moved in the same direction as the front wheel tie rods 5, 5, so that the rear wheel tie rod 18.
20' is steered in the same phase as the front wheels 7, 7. At this time, 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. In addition, in FIGS. 4 and 5, the same parts as in FIGS. 1 to 3 are given the same reference numerals to clarify the structure. First, in FIG. 4, reference numeral 34 denotes a manual selection switch for the steering angle ratio (or rear wheel steering angle, the same shall apply hereinafter), which is constructed by arranging a plurality of push buttons 35a, 35b, etc. It is placed on the maintenance panel so that the driver can operate it manually.

This selection switch 34 is the computer 31
The selection result of the steering angle ratio selected by the selection switch 34 is inputted into the computer 31.

Further, reference numeral 36 denotes a shift lever, and position detection sensors 37 and 38 are disposed near the bottom of the shift lever 36 to detect the gear position of the shift lever 36.

The stage number position detected is the low speed stage number, and in the embodiment, the position detection sensor 37 detects "low" and the position detection sensor 38 detects "back". Note that the location of this detection sensor is selected in consideration of the extremely low speed required for parallel parking, side-by-side parking, etc. The position detection sensors 37 and 38 can be, for example, a mechanical switch that opens and closes directly by the displacement action of the speed change lever 36, or an optical sensor. Then, the position detection sensor 37
38 is connected to the computer 31.

Next, the manual selection function of the steering angle ratio in the computer 31 will be explained with reference to FIG.

First, the normal operation (auto operation) in which the steering angle ratio is automatically varied in accordance with the vehicle speed will be explained.

In this case, the selection switch 34 is the first pushbutton 35
Selected by pressing a (c). As mentioned above, the heavy speed signal detected from the vehicle speed sensor 32 is sent to the computer 31.
and is converted into steering angle ratio data ka corresponding to the vehicle speed by the conversion process (a). On the other hand, the actual steering angle ratio data kbf is obtained from the position sensor 33, and each steering angle ratio data ka and kb are subjected to comparison calculation processing (b) to obtain necessary steering angle ratio correction information bxl. On the other hand, in the selection switch 34, 1) 11
Since the automatic operation ATt described above is selected, the above correction information bl is sent to the computer 3 as it is by the side selection process (c).
A correction control 1 word S1 is output from the motor 2 and changed to a necessary steering angle ratio according to the vehicle speed via the output device 37.
Supply to 9.

On the other hand, predetermined steering angle ratio information (b) is set and stored in the storage device of the computer 31. This information (for example, a plurality of steering angle ratio data kx, k2 .
k3. ... Consists of kn. And selection switch 3
4, any pushbutton other than the pushbutton 35a,
For example, if the pushbutton 35b is pressed, 1 is read out from the steering angle ratio data (from the steering angle ratio information), which is compared with the steering angle ratio data b from the position sensor 33, and corrected information b2
get. - 10,000, select switch 34 in the selection process (c)
If a pushbutton other than the auto-activated AT is pressed, in response to this, the output of the correction information b1 is stopped;
The correction information b2 is selected to be output. As a result, the output device 39 supplies a correction control signal S2y to the motor 29, and sets the steering angle ratio of the rear wheels to 1. This is the same for the other pushbuttons 35b, 35c, . . . , and the driver selects any steering angle ratio kx, k2gk3, . ...can be selected and set using the knf manual.

On the other hand, a detection signal is obtained from the position detection sensors 37 and 38, and the computer 31 judges that there is a detection signal from either of the detection sensors 37 and 38. Only when there is no detection signal, the judgment result is given to the selection process ←→, and correction information b2 for performing manual correction is output.On the other hand, when there is no detection signal, such correction information b2 is output.
will not be output.

That is, while the steering angle ratio is being set by the automatic AT, the gear shift lever 36 is in the "low" or "back" position.
Manual correction using the manual selection switch 34 can be performed only when the speed is set to a low speed stage number such as d2 (point d or less in FIG. 6). I-L
Various processes in the computer 31 are performed by the computer 31.
For example, it is executed by a predetermined control program (software) stored in a storage device.

Note that the detection signal from the vehicle speed sensor 32 can be used, for example, to detect the low speed range, but it is also possible to use a control system that sets the steering angle ratio of the rear wheels by using a gear shift lever as in the present invention. The main system ff can be configured as an independent structure, thereby avoiding complicating the main system ff and reducing reliability.

In the above example, an in-vehicle computer is used, but
It may be an electrical circuit or mechanical configuration that has the ground function.

Moreover, although the steering angle ratio of the front and rear wheels can be manually selected using the position sensor 33, the rear wheel steering angle may be similarly selected.

Further, the present invention is not limited to the embodiments, but may include a front and rear wheel steering device that hydraulically controls front and rear wheels and transmits front wheel steering angle information using hydraulic pressure, or 1) transmits 11 wheel steering angles to a computer 31 as an electrical signal. The present invention can be similarly applied to a front and rear wheel steering device, etc.

As described above, the present invention provides a front and rear wheel steering device for a vehicle that can vary the steering angle ratio of the rear wheels to the front wheels according to vehicle speed, etc.
The desired steering angle ratio can be arbitrarily changed manually regardless of the vehicle speed, etc., and such manual operation is only available when manual operation is particularly required, that is, at extremely low speeds such as when parallel parking or side-by-side parking. to be able to perform operations,
It is possible to prevent unnecessary non-driving operations due to temporary fluctuations in rear wheel steering 11 that occur when changing speeds at medium and high speeds, and to greatly improve maneuverability of the vehicle at low speeds.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the general basic structure of a vehicle equipped with front and rear wheel steering devices, Fig. 2 is an enlarged perspective view of the rear wheel steering system, and Fig. 3 (aL (bl and (cl are the rear wheel steering systems) 4 is a diagram showing the structure of the equipment, FIG. 5 is a functional block diagram of FIG. 4, and FIG. 6 is a diagram of the steering angle ratio output characteristic in FIG. 5. In the drawings, 31 is an in-vehicle computer, 32 is a vehicle speed sensor, 33 is a position sensor, 34 is a manual selection switch, 35a, 35b, 35c = - is a push button, 36 is a fi
Position detection sensor, (c) is selection processing, (gradient is steering angle ratio information, (kawa is comparison wave 9 processing, (f) is judgment processing. Patent applicant Honda Motor Co., Ltd. Agent Patent attorney ± 1. U” Patent Attorney
Person Kuni Hikodo Patent attorney Yu Koyama Figure 6 (1st person is silent)

Claims (1)

[Claims] In a vehicle front and rear wheel steering system that variably controls the steering angle of the rear wheels according to certain conditions, preset steering angle ratio (or rear wheel steering angle) information of l or 2 or more and this steering angle ratio (or rear wheel steering angle) are used. a manual switching means for selecting information (wheel steering angle) and changing the steering angle ratio (or rear wheel steering angle); and a manual switching means for detecting the lever position of the gear shift lever and operating the switching means only when the gear is at a low speed gear position. A front and rear wheel steering device for a vehicle, characterized by comprising a regulating means.