JPS6085073A - Steering device for front and rear wheels of vehicle - Google Patents

Abstract

PURPOSE:To secure the safety steering at the medium and high speed of a vehicle, through a front and rear wheel steering device capable of altering the steered angle of rear wheels, by giving warning if the speed of the vehicle exceeds a prescribed level at the time of changeover to a manual operation. CONSTITUTION:A slider 27 for altering the steered angle of rear wheels depending on that of front wheels is coupled to a motor 29, which is controlled by a signal from a computer 31 mounted on a vehicle. The instrument panel of the vehicle is fitted with a switch 34 by which the ratio of steered angle can be manually chosen. The switch 34 is connected to the computer 31 so that the steered angle ratio chosen by the switch 34 is applied to the computer. The computer 31 is connected to a warning buzzer 38 so that when the vehicle is moving more rapidly than a speed corresponding to the manually chosen ratio of steered angle, the buzzer is sounded to give warning to the driver of the vehicle.

Description

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

The present applicant has already developed a vehicle steering system (Japanese Patent Application No. 134888/1988, etc.) 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. To explain the outline of this proposed device, at low speeds, the rear wheels are steered in opposite phase to the front wheels, or almost to zero, while at high speeds, on the other hand, the rear wheels are steered in the same phase as the front wheels. The steering wheel is turned to .

The steering angle ratio is a continuous function of the vehicle speed, as shown by D in Fig. 9, and if the vehicle speed becomes higher than a predetermined vehicle speed d as a boundary, the steering angle ratio is positive, that is, in the same phase. When 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 curve, so that the functions of the steering system are compatible at low speeds and high speeds. 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 11" vehicle when entering a garage, driving on narrow curved roads, knee turns, etc. On the other hand, at high speeds, it is possible to dramatically improve maneuvering response.

However, when parallel parking at low speeds or pulling over 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, at the same time as this application, the present applicant provided a manual switching means to adjust the steering angle ratio of the rear wheels to the front wheels regardless of the vehicle speed etc.
We have proposed a front and rear wheel steering device for a vehicle that can arbitrarily change the steering angle of the front and rear wheels.

By the way, manual setting is only necessary at low speeds, as mentioned above. Therefore, a situation may arise in which the driver continues to drive the vehicle at increased speed with the manual setting in place. In this case, a problem arises in which the driver's steering effort becomes unnecessarily large under certain driving environments, such as when passing through a curve with a small turning radius, the steering wheel must be rotated considerably.

The present invention aims to eliminate such problems, and its purpose is to make it possible to arbitrarily change the steering angle ratio of the rear wheels to the front wheels, regardless of the vehicle speed or the amount of front wheel steering, and to solve this problem. Even if the driver accidentally tries to increase the vehicle speed, the system prevents the vehicle speed from increasing above a certain level to prevent loss of maneuverability at medium and high speeds.

In order to achieve the above object, the present invention is applied to a front and rear wheel steering device for a vehicle that variably controls the steering angle of the rear wheels according to certain conditions, and the main components thereof include one or more preset points. A manual switching means that selects the steering angle ratio (or rear wheel steering angle) information of and the steering angle ratio (or rear wheel steering angle) information of and changes it to an arbitrary steering angle ratio (or rear wheel steering angle); The first feature is that the vehicle is equipped with an alarm generating means that detects the vehicle speed during manual setting and issues a warning using a lamp or buzzer when the vehicle speed exceeds a certain level, reminding the driver not to increase the vehicle speed above a certain level. One feature of the invention is a vehicle speed control means that uses a roll actuator, such as a throttle controller, to detect the vehicle speed during manual setting and reduce or keep the vehicle speed constant when the vehicle speed is above a certain value. (Iiii) The second invention is characterized by suppressing the ilj speed from increasing above a certain vehicle speed.

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

First, 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.

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 (al, (bl and (C) ) is a cutaway side view showing the principle of operation.The handle shaft 2 of the handle 1 is assembled into a rack and pinion gear box 3,
Tie rods 5, 5 are connected to the left and right ends of the rack shaft 4,
A knuckle arm 6.6 supporting front wheels 7, 7 is connected to the outer ends of both tie rods 5.5, 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 snake union shaft 8 is led out from the gear box 3, and a long linkage 1qb 10 is connected to the rear end of the shaft 8 via a universal joint 9.

An input 11111112 is connected to the rear end of the linkage shaft 10 via a universal joint 11.
It is rotatably supported by +1+ receiving bracket 13. .

Furthermore, a second
A swing shaft 15 shown in detail in the figure is connected to the swing shaft 15.
A joint member 16 is loosely fitted in the middle. Tie rods 18.degree. 18 are connected to the left and right ends of the joint member 16 via ball joints 17 and 17, and the joint member 16 is swingably supported on the vehicle body side by a link 2L22 and a bracket 23. Good luck, both tie rods 1
Knuckle arms 19, 19 supporting the rear wheels 20, 20 are connected to the outer ends of the 8 degrees 18.

An arm 25 is fixed to the rear end of the swing shaft 15 at right angles to the axis, a link 26 is pivotally attached to the lower end of the arm 25, and a slider 27 is pivotally attached to the rear end of the link 26. . An output shaft 30 of a motor 29 is screwed onto the slider 27 via a ball screw mechanism 28 as shown in FIG. Fixed to.

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

Therefore, when the slider 27 is in the position shown in FIG. Because they rotate concentrically, the joint member 16 does not swing left and right, and the tie rods 18 and 18 also remain stationary.
Only the front wheels 7, 7 are steered, the rear wheels 20, 20 are not steered at all.

On the other hand, when the vehicle speed is less than the set value (ffl-'speed-), the computer 31 receives a signal from the vehicle speed sensor 32 to determine, and controls the rotation of the motor 29 according to the vehicle speed at that time, as shown in FIG. The slider 27 is moved forward as shown in the figure.As the slider 27 moves forward, the swing shaft 15 tilts downward,
The pivot point p is lower than the 11+ center of the input shaft 12 e,
The joint member 16 swings from side to side to offset (eccentrically) the rear wheel 2, moving the rear wheel 1 tie rods 18 in the opposite direction to the front wheel tie rods 5, 5.
0.20 is steered to a phase opposite to that of the front wheels 7.7. At this time, the steering angle ratio of the front and rear wheels changes continuously in accordance with the vehicle speed.

It's a moat, when the vehicle speed exceeds the set value, computer 3
1 causes the motor 29 to freely rotate in accordance with the vehicle speed at that time, and causes the slider 27 to retreat as shown in FIG. 3(c). As the slider 27 retreats, the swing shaft 15 tilts upward, and the pivot point p is offset upward by 02 from the axis of the input shaft 12, causing the rear wheel tie rods 18 and 18 to be aligned with the front wheel tie rods 5, 5. direction, thus the rear wheel 20.2
0 to the same phase as the front wheels 7.7. At this time, the steering angle ratio of the front and rear wheels also changes rapidly in accordance with the vehicle speed.

Next, an embodiment according to the first invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram of main parts, and FIG. 5 is a functional block diagram of FIG. 4. In addition, Figures 4 and 5
In the figure, parts that are the same as those in Figures 1 to 3 are designated by the same reference numerals to clarify the structure.First, in Figure 4, the reference numeral 34
is a manual selection switch for the steering angle ratio or rear wheel steering angle (the same applies hereinafter), which is configured by arranging a plurality of push buttons 35a, 35b, etc., for example. Make it possible to operate with. The selection switch 34 is connected to the computer 31 and inputs the selection result of the steering angle ratio selected by the selection switch 34 to the computer 31. On the other hand, a warning lamp 37 is provided at a required position on the instrument panel 36 that is visible to the driver, and a warning buzzer 38 is provided at a required position in the vehicle interior. is connected to the computer 31. Note that either the lamp 37 or the buzzer 38 may be used.

Next, the functions of the computer shown in FIG. 4 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 is selected, for example, by pressing the first push button 35a of the selection switch 34. As described above, the vehicle speed signal detected from the vehicle speed sensor 32 is input 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 position sensor 33 obtains actual steering angle ratio data Kb, and the respective steering angle ratio data Ka and Kb are subjected to comparison calculation processing (b) to obtain necessary steering angle ratio correction information b1. On the other hand, in the selection switch 34, the aforementioned correction information b1 is outputted from the computer 31 by the above-mentioned selection process (c), indicating whether T has been selected for the automatic operation, and the correction information b1 is outputted via the output device 39 according to the vehicle speed. A correction control signal S1 for changing the steering angle ratio to a required value is supplied to the motor 29σ.

Next, manual operation will be explained. Predetermined steering angle ratio information) is set and stored in the storage device of the computer 31. This information) consists of a plurality of steering angle ratio data having an arbitrary size, 1+K2+KB...Kn. Then, in the selection switch 34, press the push button 35.
If you press any pushbutton other than &, for example, pushbutton 35b, 1 is read out in the steering angle ratio data (to read the steering angle ratio information),
This is compared with the steering angle ratio data Kb from the position sensor 33 and subjected to calculation processing (e) to obtain correction information b2. On the other hand, in the selection process (c), when the selection switch 34
If a pushbutton other than T is pressed, this is received, the output of the modification information b1 is stopped, and the modification information b2 is selected to be output. As a result, the output device 39 supplies a correction control signal S2 to the motor 529, and sets the steering angle ratio of the rear wheels to 1. This applies to other pushbuttons y"35b.
, 35c, . . . , the driver selects any steering angle ratio i (, , K2
．． K8...Kn can be selected and set manually.

In addition, the computer 31 compares the vehicle speed signal (actual measurement value) detected from the vehicle speed sensor 32 with a preset constant vehicle speed (reference value (g)), and determines whether the actual value is equal to or higher than the reference value (g). Execute the judgment process (to) to judge whether or not. If the vehicle speed is above the reference value (G), that is, above a certain vehicle speed, an output signal is supplied to the output device 40, thereby causing the output device 40 to turn on the warning lamp 37 or to turn on the alarm lamp 37 intermittently if necessary. In addition, the alarm buzzer 38
sounds to alert the driver of the condition. It should be noted that such judgment processing is executed only when manual setting is set, and in a normal automatic operation type T, the output signal for operating the output device 40 is always zero.

Next, an embodiment according to the second invention will be described with reference to FIGS. 6 to 8. 6 is a block diagram of main parts, FIG. 7 is a sectional block diagram of the actuator shown in FIG. 6, and FIG. 8 is a functional block diagram of FIG. 6.

Note that in FIGS. 6 to 8, the same parts as in FIGS. 4 and 5 are designated by the same reference numerals to clarify the structure, and detailed explanation thereof will be omitted. First, in FIG. 6, reference numeral 41 is an automatic constant speed traveling device that maintains the vehicle speed constant on expressways and the like even when the accelerator pedal is not depressed. The same device 4
1 includes a throttle control actuator 42,
As is clear from FIG. 7, this actuator 42 receives a signal S3 (energization time) from a control unit (not shown).
The vacuum valve 43 for acceleration and the vent valve 44 for deceleration are opened and closed, and negative pressure of the engine or atmospheric air is introduced into the actuator negative pressure chamber P to operate the diaphragm 45, and a pedal link coupled to the diaphragm 45. It has the function of controlling the throttle opening by controlling the Note that arrow Ft.

indicates an atmospheric route, and arrow Fl2 indicates a negative pressure route. The vacuum valve 43 introduces negative pressure while energized, and cuts off the negative pressure when the energization is cut off. The vent valve 44 shuts off the atmosphere and maintains the negative pressure in the negative pressure chamber P while energized, and introduces the atmosphere when the energization is interrupted. In addition, 46 is a safety valve that shuts off the atmosphere when energized and introduces the atmosphere when not energized, which accelerates deceleration when canceling, etc. In addition, numeral 47 is a vacuum accumulator, 48 is a filter, 49 is a check valve, 50 is a carburetor insulator, and 51 is a pedal link coupling portion.

In this embodiment, an output control device 52 is connected to the vacuum valve 43 and vent valve 44 of the actuator 42 to drive each valve 43 and 44, and the computer 31 is connected to the output control device 52.
If necessary, a control signal S4 is sent. Therefore, the computer 31
Actuated by.

By operating the eta 42, the throttle opening degree and the vehicle speed can be controlled.

Next, the control function of the actuator 42 in the computer 31 will be explained with reference to FIG.

The automatic operation and manual operation described in FIG. 5 are exactly the same in FIG. 7, and detailed explanation thereof will be omitted. Suppose. In this case computer 3
1, the vehicle speed signal detected from the vehicle speed sensor 32 (
The actual measured value) is compared with a preset constant vehicle speed (reference value (g)), and the judgment process (man) is executed to determine whether or not the actual measured value is greater than or equal to the reference value (g). (stomach)
If the vehicle speed is greater than or equal to a certain vehicle speed, the control signal S4 is
is outputted and supplied to the output control device 52, and the actuator 42 is driven and controlled to control the throttle opening degree by 11 as described above, thereby reducing the vehicle speed and maintaining it constant. As a result, the vehicle speed is suppressed so as not to increase above a certain vehicle speedC) In each embodiment, various processes in the computer 31 are carried out by a predetermined control program (software) stored in the computer 31. executed. However, in addition to the on-vehicle computer 31 as described above, it is also possible to construct an electric circuit consisting of a combination of its surveying functions.

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 also be selected in the same way.

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

As described above, the front and rear wheel steering device for a vehicle according to the present invention can arbitrarily change the steering angle ratio of the rear wheels to the front wheels regardless of the vehicle speed, etc., and can easily perform parallel parking and side-to-side parking at low speeds. In addition to the basic effect of greatly improving the maneuverability of the vehicle, even if the driver attempts to reduce the vehicle speed with manual settings, an alarm will be activated to prevent the vehicle speed from exceeding a certain level. Since the driver is reminded not to increase the speed (first invention), or the vehicle speed control means is used to prevent the vehicle speed from increasing above a certain level (second invention), there is no loss of maneuvering responsiveness at medium to high speeds. .

[Brief explanation of drawings]

Figure 1 is a perspective view showing the general basic structure of a vehicle equipped with a front and rear wheel steering system, Figure 2 is an enlarged perspective view of the rear wheel steering system, and Figure 3 (aL (bl and (C) shows its operating principle). FIG. 4 is a main part configuration diagram according to the first invention, and FIG.
FIG. 6 is a functional block diagram of the main part according to the second invention, FIG. 7 is a cross-sectional configuration diagram of the actuator shown in FIG. 6,
FIG. 8 is a functional block diagram of FIG. 6, and FIG. 9 is a steering angle ratio output characteristic diagram in FIG. 5 or FIG. 7. In the drawing, 31 is an onboard computer, 32 is a vehicle speed sensor, 33 (d position sensor, 341d, manual selection switch, 35a, 35b, 35c... are push buttons, 3
7 is a warning lamp, 38 is a 15'f warning buzzer, 40 is an output device fL 421J: Throttle controller I/roll actuator, 52 is in front of the output control device, (c) c-L selection process,
) is steering angle ratio information, (e) is comparison calculation processing, (e), (
The first sword is judgment processing. Figure 3 Figure 4 Figure 6 Figure 7

Claims (4)

[Claims] (1) 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, the steering angle ratio (or rear wheel steering angle) of one or more preset pieces of information and A manual compliance means that selects the steering angle ratio (or rear wheel steering angle) information and changes it to an arbitrary steering angle ratio (or rear wheel steering angle), and an alarm that detects the vehicle speed and issues an alarm when the vehicle speed exceeds a certain value when set manually. 1. A front and rear wheel steering device for a vehicle, comprising: generating means. (2) 'I'F characterized in that the alarm generating means C1 uses a light emitting means such as a lamp: Fl/Claim 1
11. Front and rear wheel steering device for a vehicle according to item 1. (3) The front and rear wheel steering system for a vehicle as set forth in claim 1, characterized in that the warning generating means 11S1 and sounding means such as a buzzer are used. (4) In a vehicle front and rear wheel steering system that variably controls the steering angle of the rear wheels according to certain conditions, the preset 1 or 2
The above steering angle ratio (or rear wheel turning angle) information and this steering angle ratio (
(or rear wheel steering angle) information and change it to an arbitrary steering angle ratio (or rear wheel steering angle), and a manual switching means that detects the vehicle speed during manual setting and controls the vehicle speed to decrease or keep it constant when the vehicle speed is above a certain speed. (5) The vehicle according to claim 4, characterized in that the vehicle speed control means is controlled by a throttle control actuator. Front and rear wheel steering system.