JPS6189172A - Four wheel steering device for vehicle - Google Patents

Abstract

PURPOSE:To prevent abnormal steering of rear wheels by detecting misestablish ment of steering ratio early depending on the output from rear wheel steering ratio detecting sensor, and by distinguishing whether the steering ratio is in the abnormal region which is established as required by the speed of vehicle. CONSTITUTION:When the rear wheel steering ratio is variably controlled abnormally, and the real rotated angle of the control shaft is in the abnormal region depending on the output signal from the steering ratio detecting sensor 31 and the car speed detecting sensor 30, the abnormality distinguishing measures 39 distinguished that the aforesaid rotated angle exists in the abnormal region. Then, owing to the output signal from the OR circuit of 48 of the abnormality distinguishing measures 39, the warning device 49 operates and a warning is issued, and the drive motor 29 of the rear wheel steering mechanism converts into the two wheel steering state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel steering system for a vehicle, which steers the rear wheels in response to the steering of the front wheels.

(Prior Art) Conventionally, as a four-wheel steering M'11 for this type of vehicle,
For example, as disclosed in Japanese Unexamined Patent Publication No. 59-92263, a steering device that steers the front wheels, and a variable steering ratio rear wheel steering mechanism that varies the ratio of the rear wheel steering angle to the front wheel steering angle. , the rear wheel steering includes a control means for variably controlling a steering ratio of (1'4) according to the vehicle speed, and the rear wheel steering device tM
Li? Depending on the steering of the i-wheel and the vehicle speed, for example, at high speeds, the wheels should be steered in the opposite phase to the front wheels from the standpoint of maneuverability, and at high speeds, the wheels should be steered in the same phase as the front wheels for stability. ζ things are known.

(Problem to be Solved by the Invention) However, in the conventional system described above, a failure occurs in the controller "J3" and an incorrect control signal is sent to the rear wheel steering mechanism.
J: In the Uninaru SS meeting, there is also a problem with the rear wheel steering for the M on No. 11 (the steering ratio of 1°4 is changed, and the rear wheels are steered to a different angle of 1:3. If, in 8th gear, the rear wheels are incorrectly steered to the opposite phase to the front wheels, the vehicle will make an n turn, resulting in what is called a spin. This can lead to a very dangerous situation.

In view of the above, the present invention aims to detect the error at an early stage when the rear wheel steering ratio is set incorrectly. The purpose is to take appropriate measures to deal with abnormal steering.

(Means for Solving the Problem) In order to quickly achieve the above object, the solution of the present invention is a four-wheel steering system for a vehicle in which the front wheels are steered (the rear wheels are steered). A rear wheel steering mechanism with a variable steering ratio in which the ratio of front wheel steering angle to 1 rear wheel steering angle is variable, and the steering ratio of the rear wheel steering device 4:■ is variable according to medium speed. - a sensor for detecting the steering ratio of the rear wheel steering mechanism; and a sensor for detecting the steering ratio of the rear wheel steering mechanism; It consists of an abnormality determining means that determines whether or not there is an abnormality.

(Function) According to the configuration described in F, in the present invention, if the steering ratio of the rear wheel steering mechanism is set incorrectly due to the control means'
The abnormality determining means receives the output from the sensor ' that detects the steering ratio and determines and detects that the steering ratio is incorrectly set.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 and 2 show a four-wheel steering system for a vehicle as an embodiment of the present invention, in which 1 is a steering system for steering left and right front wheels 2; , Rack & Binion II (M4), left and right front wheel tie rods 5, and left and right front wheel knuckle arms 6.

Reference numeral 7 denotes a rear wheel steering mechanism for steering left and right rear wheels 8, and both ends of the rear wheel steering mechanism 7 are connected to the left and right rear wheels 8 via a rear wheel knuckle arm 9 and a rear wheel tie rod 1○. The hydraulic actuator 12 includes a rod 11 that extends in the vehicle width direction, and a hydraulic actuator 12 that uses the rod 11 as an operating rod. The hydraulic actuator 12 has a left-turning hydraulic chamber and a right-turning hydraulic chamber (not shown) inside thereof, and these pressure chambers are connected to the oil supply direction to the hydraulic actuator 12 through hydraulic passages 13a and 13b, respectively. J3 and a control valve 14 that controls oil pressure, the control valve 14
An oil tank 18 is connected to the oil tank 18 through an oil supply passage 16 and an oil return passage 17 with a hydraulic pump 15 interposed therebetween.

In addition, an operating rod 19 that can reciprocate in the vehicle width direction is connected to the control valve 14 and is connected to the control valve 14, and when the control valve 14 moves from the reference position to the side C in the figure, the control valve 14 is connected to an operating rod 19 that is movable back and forth in the vehicle width direction. Pressure oil is controlled [l-le valve 1]
4 to the left turning hydraulic chamber of the hydraulic actuator 12, and the hydraulic actuator 12 moves the rod 11 to the right and steers the rear wheel 8 to the left. I-Position J, move to left side 1I
When a JJ occurs, pressure oil from the hydraulic pump 15 is supplied through the control valve 14 to the right-turning hydraulic chamber of the hydraulic actuator 12, and the hydraulic actuator 12 moves the rod 11 to the left and steers the rear wheel 8 to the right. , move the operating rod 19 at the same time! I'J] Pressure oil from the hydraulic pump 15 is supplied to the control valve 1 according to ffi.
The pressure is reduced at 4.

This allows the steering angle of the rear wheels 8 to be adjusted (111
has been completed.

Further, the rear wheel steering mechanism 7 includes the steering device 1
The steering input shaft 20 is provided with a steering input shaft 20 extending in the longitudinal direction of the vehicle body that receives the steering force (rack & binion (movement in the vehicle width direction of the rack 4a of 4 sides) as a rotational force, and the rear end of the steering input shaft 20 is A bevel gear ~721 is provided.The driven tooth width side shaft portion 21a of the bevel gear 21 is located on the same axis j≦191 (vehicle width direction) as the operating rod 19, and the side shaft of the wave gear A proximal end of a telescopic arm member 22 is connected and fixed to the portion 21a, and an inclined rod 23 is movably passed through L'1 through the distal end of the arm member 22 of the arm A1. Both the passing direction and the inclination angles of j3 and 41 can be changed to some extent.

The -6;H part of the tilt [] 3 is rotatably connected to the operating rod 19 at a predetermined angle with the axis Q1, while the other end has a lever member. 2
One end of the lever member 24 is connected to the other end of the lever member 24.
The controller 1-1 is rotatably supported at the lower width portion of the control 1-1-25 extending in the vertical direction via a support shaft 2G.

Above: Conl-[']-Rusuke 25. is its axis 9. is the bevel j above! It is arranged to be orthogonal to the driven gear side shaft portion 21a of X721 or the axis 91 of the operating rod 19, and the support shaft 26 is located at the intersection of both axes U+ and Q2. A drive motor 29 is drivingly connected to the control shaft 25 via a bevel gear (27J5) 728. However, 1. By the operation of 29, the [1-
The axis 25 is the axis $! 92 to change the inclination angle of the support @26 with respect to the driven shaft portion 21a of the bevel gear 21 or the axis Q1 of the operating rod 19, the support shaft 2
The direction of the rotation trajectory of the lever member 24 that rotates around 6 is changed, and the tilted rod 23 connected to the lever member 24 is used to operate ('l L:] the turad 9 by 1.
(1″
4 has been completed. Therefore, rear wheel steering I shallow 4747 LJ,
, the rotation angle of the control @ 25, which is a component thereof, or the axis 91 of the operating rod 19
By changing the steering angle, the direction and transmission ratio of the steering force from the steering device 1 to the rear wheel tie rods 10 can be made variable, and the ratio of the rear wheel steering angle to the front wheel steering angle, that is, the steering ratio. It is configured to make it variable.

Furthermore, 30 is a vehicle speed detection sensor for detecting medium speed, and 31 is a steering ratio detection sensor installed at the upper end of the control J-roll shaft 25 of the rear wheel steering mechanism 7. The ratio detection sensor 3'1 has a plurality of slits 32,32. ..., a disc-shaped slit plate 33 fitted to the upper end of the control shaft 25, a light emitting section 34 disposed below the slit plate 33 facing the slit 32, and above the slit plate 33. A light receiving section 35 is disposed opposite the light emitting section 34 with the slit plate 33 interposed therebetween, and a performance section 36 is connected to the light receiving section 35. Surin 1-32.32 of the slit plate 33. ... are offset from each other in the circumferential direction of the slit plate 33, so that the light emitted from the light emitting section 34 is shifted by the angle of rotation of the slit plate 33 or the control shaft 25, respectively. A set of Surin l-32,・
... and reaches the light receiving section 35 through the reaching light, and based on this arriving light, the rotation angle of the control shaft 25, that is, the steering ratio of the rear wheel steering mechanism 7, is determined and detected in the worship section 36. ing.

Each of the detection signals from the medium speed detection sensor 30 and the steering ratio detection sensor 31 is input to a controller 37.
A control means for variably controlling the steering ratio of 47 depending on the middle;
i
It also includes an abnormality determining means for determining whether or not there is a strain. Although the specific circuit of the L open control means is not shown, the control shown in FIG.
), and based on the control mode A, an output signal is issued to the drive motor 29 of the rear wheel steering mechanism 7 to perform variable control of the steering ratio. In the control system 7-door A, the rear wheels 8 are switched to the front wheels 2 at low speeds for maneuverability.
The rotation angle of the control shaft 25 is set to negative Ifl so that it is steered in the opposite phase to ? At S speed, the steering angle is similar to a cosine curve in which the rotation angle of the control shaft 25 takes a positive value so that the rear wheels 8 are steered in the same phase as the front wheels 2 from the viewpoint of stability.

On the other hand, the electronic circuit of the abnormality determining means is shown in FIG. In FIG. 6, 38a, 38b.

38c and 38d are the first and second output terminals of the medium speed detection sensor 30, respectively. Second. The third and fourth terminals 38a and 38d are respectively connected to the terminals 38a and 38d in FIG.
The first section is a medium speed region (a medium speed region of about 60 km/h or more) in which the control shaft 25 is rotated by 1 rotation angle. Second. 3rd and 4th car speed pirate ■
At 1.-V, l, the output 13 is output to the three abnormality determining means. :K1:,
/40a, 40b, 40c Jj and 40d are the first output terminals of the steering ratio detection sensor 31, respectively. Second.
third and first I terminals, each terminal 40a-/
10 (I is the first to fourth vehicle speed ranges V1 to V4 in which the actual rotation angle of the control shaft 25 is shown in FIG.
What is the FIJ angle in each abnormal region B1・-Bi of F (
It is designed to output (Aq to rI: normal discriminating means 39) when it is present.

In addition, each abnormal region B+ in the first to fourth medium speed regions v1 to v4
, ~B4 is set as a region below the lowest control axis rotation angle in each vehicle speed range V1 to v4 of control mode A (for example, the control axis rotation angle is zero or less in the first vehicle speed range v1). has been done.

The three abnormality determination means of the module C1 include a first A circuit 41 which receives output signals g from the first and second terminals 4.0a and 4oh of the steering ratio detection sensor "31," and The 2nd A circuit 42 receives the output No. 15 from the first to third terminals 40a to 40c of the steering ratio detection sensor 31, respectively, and the first to third terminals of the steering ratio detection pincer 31. Q
3A circuit 43 which receives output signals from A and 40(), respectively, and a first terminal AOa of the steering ratio detection sensor 31.
tJ3 and the output signal from the first terminal 38a of the medium speed detection sensor 30, the actual rotation angle of the control @25 is in the first vehicle speed region ■1 in FIG. 5 and the abnormal region B.
Within 1 (first AND circuit that determines whether this is a cup or a cup/'I4
and the first Δ)' circuit 41 and the vehicle speed detection sensor 30.
It is determined whether or not the actual rotation angle of the control shaft 250 is within the abnormality region B2 in the second vehicle speed region 2 in a5 in FIG. The output signals from the second AND circuit 45, the second OR circuit 42, and the third terminal 38c of the vehicle speed detection sensor 30 are received, and the actual rotation angle of the hitor shaft 25 is determined as shown in FIG. A third AND circuit 46 that determines whether or not the vehicle is within the abnormal region B3 in the third vehicle speed region kiv3 by 1'Jj; The output signal from the third OR circuit 43 between F and the eleventh terminal 38d of the medium speed detection sensor 3o is received, and the actual rotation angle of the control shaft 25 is determined in the fourth vehicle speed region II1.
A fourth A1: circuit 47 for determining whether or not the area is within the abnormal region B4 in V4, and the first to fourth AND circuits 44-.
The 4th A circuit 71 receives the output C bows from 47 respectively.
It consists of 8 and the actual control[)-le'll1b 25
(When it is determined that the angle J is within the abnormal area B1 to B4, a warning device i is output from the fourth OR circuit 48.
T? When an alarm is issued by outputting an activation signal to 49, a control signal is output to the drive motor 29 of the rear wheel steering wheel 7 to bring the rotation angle of the control 1-roll shaft 25 to zero: L It is configured so that the steering force from the resteering device 1 is not transmitted to the rear wheel tie rod 10, so to speak, a two-wheel steering state.

/A, please refer to the above example or control [1
- When the steering ratio of the lateral 7 according to the contact wheel steering is controlled 1111 to 1 step according to the medium speed by the control means of the wheel 37, the above steering ratio (control [rotation of the call shaft 25 As shown in FIG. Then, the rear wheels 8 are steered to the same (?L) phase as the front wheels 2.

1]J,'' The 11th gear stage was broken and the rear wheel steering (shallow R'
The steering ratio of +7 was abnormally controlled and the actual rotation angle of the control shaft 25 was distorted as shown in Fig. 5.
When the rotation angle falls within the ranges B1 to B4, the abnormality determination means 39 of the steering wheel 37 outputs the output signals from the steering ratio detection sensor 31 and the vehicle speed detection sensor 30, respectively. It is determined that the rotation angle of the roller @25 is within the abnormal ranges B1 to B4.

That is, when the vehicle is in the abnormal region 81 in the first vehicle speed region V;, the first AND circuit 44 of the first stage abnormality determination 39 connects the first terminal/IoaJ3 of the steering ratio detection sensor 31 and the first terminal of the medium speed detection sensor 30. 38a, and when the vehicle is in the abnormal region B2 in the second vehicle speed region v2, the second AND circuit 45 of the abnormality determination method 39 outputs the first OR circuit 41 J5 J: and the vehicle speed detection sensor 30. The output signals from the second terminals 38b are received and determined, and when the vehicle is in the abnormal region B3 in the third vehicle speed region v3, the third AND circuit 46 of the abnormality determination method 39 is activated by the second OR circuit 42 J5.
J: Receives the output signals from the 39th:: child 38G of the vehicle speed detection sensor 30 and determines C, and further determines that there is no abnormality when the number is in the abnormal area B4 in the 4th and 11th speed region 4. The fourth AND circuits 47 of the three means receive the output horn signals from the third OR circuit 43 and the 40'ii child 38d of the medium-speed detection unit 30, respectively, and determine the difference between the two. 81--When it is determined that there is a BJ, a warning is sent from the 4A circuit/I8 of the abnormality determining means 39.
Far f and H are output to ll 49 to give an alarm, and control (+'i) is output to the drive heater 29 at 1° and 7 to indicate the state of two-wheel steering. As a result, it is possible to prevent the steering ratio of the rear wheel steering mechanism 7 from being abnormally variable controlled by the control means, especially at high speeds. It is possible to prevent the steering wheel from being steered in a phase opposite to that of the front wheels 2, resulting in an extremely dangerous situation, thereby improving safety.

It should be noted that the present invention is not limited to the above embodiments.
, which includes various other variations.

19! For example, Embodiment C described in L has an abnormality determining means 39 that can determine whether the rear wheels are steered (the steering ratio of the rear wheel steering wheel 7 is set in advance according to the medium speed!), and whether the vehicle is in an abnormal region or not. , is composed of an electronic circuit consisting of 7nd circuits 44 to 47 and OR circuits 41 to 43.47, but instead of this power j' circuit, a microcombination circuit is used and Of course, the best thing to do is ℃.

In addition, the present invention is limited to one multi-wheel steering system with variable steering ratio (Ii 7) (1) configured using one oil-repellent coator 124 as in the above embodiment; Something that consists of one stage?l-a-)Cm Good.

(Effects of the Invention) As described above, according to the four-wheel steering system for a vehicle according to the present invention, when the steering ratio of the rear wheel steering mechanism is incorrectly set due to a failure of the Sill 1711 means, In Tatsumi, the jit determination means can determine and detect that the steering ratio is set incorrectly by receiving the output from the sensor that detects the steering ratio, so the rear wheels can be abnormally steered. Valid Ii before! It is possible to take one risk and ensure safety.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG.
A schematic diagram showing the overall fM configuration of the transport steering system;
Figure 13 is a detailed configuration diagram of the rear wheel steering IAI R'i section, Figure 3 is a longitudinal cross-sectional side view of μ steering ratio detection, and Figure 4 is a detailed diagram of the rear wheel steering IAI R'i section.
A top view of the slit plate of the steering ratio detection sensor, Figure m5 (
Figure 5 shows the electronic circuit diagram of the abnormality determining means. .

Claims (2)

[Claims] (1) A four-wheel steering system for a vehicle that steers the rear wheels in accordance with the steering of the front wheels, with a variable steering ratio that varies the ratio of the rear wheel steering angle to the front wheel steering angle. a wheel steering mechanism; a control means for variably controlling the steering ratio of the rear wheel steering mechanism according to the vehicle speed; a sensor for detecting the steering ratio of the rear wheel steering mechanism; 1. A four-wheel steering system for a vehicle, comprising abnormality determining means for determining whether or not a steering ratio is in an abnormality range preset according to vehicle speed. (2) The rear wheel steering mechanism is configured to vary the direction and transmission ratio of the steering force from the front wheel steering angle steering device to the rear wheel tie rods. A four-wheel steering device for the vehicle described.