JPH036550Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a rear wheel steering regulating device in a front and rear wheel steered vehicle capable of steering the rear wheels of the vehicle in conjunction with the steering operation of the front wheels.

(Prior Art) Conventional front and rear wheel steered vehicles are broadly classified into vehicles equipped with a mechanical rear wheel steering mechanism and vehicles equipped with an electrohydraulic rear wheel steering mechanism. For vehicles equipped with a mechanical rear wheel steering mechanism, for example, JP-A-55-91458, JP-A-58-30869, JP-A-58-30870, JP-A-58
As proposed in No. 30871, etc., the front wheel side steering linkage and the rear wheel side steering linkage are connected via a connecting rod and an input conversion mechanism, and this input conversion mechanism allows the steering linkage on the rear wheel side to be connected. By operating the linkage according to the steering angle of the front wheels, the rear wheels are steered in conjunction with the steering operation of the front wheels.

On the other hand, in vehicles equipped with an electro-hydraulic rear wheel steering mechanism, for example, Japanese Patent Laid-Open No. 57-11173,
As proposed in No. 15066, Utility Model Application No. 19172, etc., a hydraulic actuator is installed between a pair of left and right tie rods connected to a pair of left and right rear wheels via knuckle arms, respectively. Both outer ends of the piston rod are connected to the inner ends of the tie rod, and the supply and discharge of hydraulic pressure to and from the cylinders of the hydraulic actuator are controlled in accordance with the steering state of the front wheels to move the piston rod left and right, thereby controlling the rear wheels. The vehicle is configured to be steered in conjunction with the steering operation of the front wheels. In addition, in this type of vehicle, the steering angle of the rear wheels is controlled so that it is in the opposite phase (in the opposite direction) to the steering angle of the front wheels at low speeds and in phase (in the same direction) at high speeds, and as the vehicle speed increases, Generally, it is controlled so that it gradually decreases. Therefore, the hydraulic actuator is operated so that the horizontal movement of its piston rod gradually decreases as the vehicle speed increases. By the way, in this type of vehicle, the rear wheels are steered to the above-mentioned state only by electro-hydraulic means, so the rear wheels are not steered beyond the maximum steering angle allowed according to the vehicle speed. This is desirable.

(Purpose of the invention) The present invention was devised in view of the above-mentioned circumstances, and its main purpose is to provide a means for regulating the steering of the rear wheels beyond a predetermined value, and to reduce the vehicle speed when this means is not in operation. The purpose is to prevent the rear wheels from being steered beyond the maximum steering angle allowed in accordance with the vehicle speed.

(Structure of the invention) The present invention relates to a front-rear wheel steering vehicle that is equipped with a front wheel steering mechanism that operates by steering wheel operation to steer the front wheels, and a rear wheel steering mechanism that steers the rear wheels according to the driving condition of the vehicle. It is a rear wheel steering regulating device, and the steering regulating device includes a rear wheel steering regulating means for regulating steering of the rear wheels beyond a predetermined value, a shift regulating means for regulating shift-up of a transmission beyond a predetermined value, and each of these components. Its feature lies in that it is provided with an actuating means that releases the speed change restriction of the transmission when the restricting means is actuated to restrict the steering of the rear wheels.

(Operations and Effects of the Invention) As a result, in the steering regulating device of the present invention, when the steering of the rear wheels is regulated to less than a predetermined value, the gear shift regulation of the transmission is released and the gear shift can be shifted up at will. The vehicle speed can be increased by
Furthermore, if rear wheel steering is not regulated, shifting of the transmission beyond a specified level is regulated.
The vehicle speed cannot be increased above a predetermined value.
Therefore, according to the steering restriction device, the maximum steering angle of the rear wheels can be restricted to an allowable range corresponding to the vehicle speed.

(Example) Hereinafter, the present invention will be described based on the drawings. FIG. 1 shows a schematic configuration of an example of a front and rear wheel steered vehicle to which the present invention is applied.

In such a vehicle, the rear wheels 11 are steered in conjunction with the front wheels 12, and each rear wheel 11 is connected to each tie rod 14 via a knuckle arm 13. Further, each tie rod 14 is connected at its inner end to a hydraulic actuator 20a of a rear wheel steering mechanism, which will be described later.

The rear wheel steering mechanism includes a hydraulic actuator 20a,
It is composed of a hydraulic control device 20b that drives this, and an electric control device 20c that controls this. The hydraulic actuator 20a is a cylinder 21
and a piston rod 22 that fluidly and slidably penetrates both ends of the cylinder 21 and has a piston that divides the interior into left and right oil chambers.The inner end of each tie rod 14 is connected to the outer end of the piston rod 22. Both oil chambers of the cylinder 21 are connected to the servo valve 23 of the hydraulic control device 20b. The hydraulic control device 20b includes a servo valve 23 and a hydraulic pump 24 driven by an engine, and supplies hydraulic oil from the hydraulic pump 24 to the servo valve 23.
The switching operation functions to supply hydraulic oil to one oil chamber of the cylinder 21 of the hydraulic actuator 20a and to discharge hydraulic oil from the other oil chamber. As a result, the piston rod 22 of the hydraulic actuator 20a is moved left and right to steer the rear wheel 11. In such a hydraulic control device 20b, the servo valve 23 is controlled by an electric control device 20c.

The electric control device 20c is a known one, and is composed of a vehicle speed sensor 25a, a front wheel steering angle sensor 25b, a command circuit 26, a servo amplifier 27, and a potentiometer 28 that detects the displacement of the piston rod 22. . This electric control device 20c
, the rear wheel steering angle δr is determined by the command circuit 26 based on the vehicle speed V and the front wheel steering angle δf from the vehicle speed sensor 25a and the front wheel steering angle sensor 25b, and this value is sent to the servo amplifier 27. The servo amplifier 27 switches the servo valve 23 to control supply and discharge of hydraulic oil to and from the cylinder 21 of the hydraulic actuator 20a, and controls the rear wheel 11 to the steering angle δr determined by the command circuit 26. The potentiometer 28 detects the displacement of the piston rod 22 and feeds it back to the servo amplifier 27, thereby performing feedback control. In this embodiment, the rear wheel steering angle δr is the second in relation to the front wheel steering angle δf.
It is controlled as shown in the figure.

Accordingly, in this embodiment, the above-described vehicle is equipped with a steering regulation device 30 shown in FIG. 3. The steering regulation device 30 includes a pair of left and right spacers 30.
a, 30a, an operating mechanism 30b, and a shift operation regulating mechanism 30c, and both spacers 30
a, 30b are the rear wheel steering regulating means of the present invention, the operating mechanism 30b is the actuating means of the present invention, and the regulating mechanism 30
c corresponds to the speed change regulating means of the present invention.

The operating mechanism 30b includes a rotating arm 31 rotatably supported in the driver's cab, and one rotating end of the arm 31 has first and second pushable cables 32.
a and 32b are connected. The first push-pull cable 32a is connected at its tip to two sub-pushable cables 32a1, 32b2, and each of these sub-cables 32a1, 32a2
Spacers 30a, 30a shown in FIG. 3 are connected to the tips of the . Further, an operating lever 33 is provided protruding from the other rotating end of the rotating arm 31.
When the operating lever 33 is engaged with one end 34a of the circular arc groove provided on the operating panel 34, each spacer 3
0a and 30a are pulled up, and the operation lever 33
When pulled toward the other end portion 34b of the arcuate groove and positioned in the corresponding portion, each spacer 30a, 30a protrudes from the first pushable cable 32a and each sub-cable 32a1, 32a2, and each spacer 30a,
30a is interposed between the stoppers 21a, 21a at both ends of the cylinder 21 and the stoppers 14a, 14a at the inner ends of each tie rod 14, as shown in FIG.

The second pushable cable 32b is connected to the regulating mechanism 30c at its tip. As shown in FIGS. 4 to 6, the regulating mechanism 30c is slidable on the operation panel 35 that guides the shift lever 15 of the transmission to each shift position and holds it at the same position, and on the lower surface side of the operation panel 35. A pair of regulation plates 36a, 3 assembled to
6b, and both of these regulating plates 36a, 36b are connected to the second pushable cable 32b via a frame-like arm 37. The operation panel 35 has 1st to 5th speeds.
It is provided with a guide groove 35a for speed and reverse. Further, the first regulating plate 36a includes protrusions 36a1 and 36a2 for opening and closing the third and fifth gear grooves 35a1 and 35a2 in the guide groove 35a. It is provided with protrusions 36b1 and 36b2 that open and close the grooves 35a3 and 35a4. This results in
The operating lever 33 is connected to one end 3 of the arcuate groove of the operating panel 34.
4a, each regulation plate 36a, 3
6b is the 2nd speed ~ in the guide groove 35a of the operation panel 35
The fifth speed grooves 35a1 to 35a4 are closed, and when the operating lever 33 is operated to the other end 34b of the arcuate groove, all the grooves are opened.

In the steering regulating device 30 configured in this way, when the operating lever 33 of the operating mechanism 30b is located at one end 34a of the arcuate groove, both spacers 3
0a and 30a are pulled up and inactive,
In addition, the second to fifth speed grooves 35a1 to 35a4 of the guide groove 35a on the operation panel 35 of the regulation mechanism 30c are in a closed state. For this reason, the transmission cannot be shifted up from 2nd speed to 5th speed, and the shift lever 15 has a 1st speed or reverse groove 35a5,
35a6, the vehicle does not go above a predetermined speed. When the operating lever 33 is operated to move the arcuate groove to the other end 34b, both spacers 30a, 3
0a is pushed and the stoppers 21a, 21a of the protruding cylinder 21 and the stoppers 1 of each tie rod 14 are moved.
4a, 14a, and each regulation plate plate 36a, 36b of the regulation mechanism 30c slides to open the operation panel 35.
All parts of the guide groove 35a are opened (see FIGS. 3 and 4). For this reason, change the transmission to 2nd gear
It is possible to increase the vehicle speed by shifting up to 5th gear, but the stroke length of the piston rod 22 of the hydraulic actuator 20a is different from each spacer 30a,
It is regulated to a predetermined length by 30a and 30a. Therefore, even if the piston rod 22 tries to move laterally by more than a predetermined amount, when inside the vehicle or at high speed, the stroke is regulated to a predetermined value by the action of the spacers 30a, 30a, and the maximum steering angle of the rear wheels 11 is allowed depending on the vehicle speed. It can be regulated to the extent that

(Modification) Note that in the above embodiment, the 2nd to 2nd gears of the transmission
Although we have shown an example in which a mechanical mechanism is adopted as a regulation mechanism for regulating the shift-up to the 5th gear, if an automatic transmission is adopted in this invention, the 7th gear
It is possible to employ an electrical mechanism as shown in the figure. In this modification, reference numeral 37 is a switch that is opened and closed by operating the operating lever 33, and is closed when each spacer 30a, 30a is in a non-operating state. The system is configured so that it does not output a signal prompting a gear shift. The other aspects of the steering regulating device are constructed in substantially the same manner as in the above embodiment, and produce the same effects as in the embodiment.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an example of a vehicle to which the present invention is applied, Fig. 2 is a graph showing the steering state of the rear wheels in the same vehicle, and Fig. 3 is an example of the steering restriction device according to the present invention. 4 is a bottom view of the regulating mechanism in the same device, FIG. 5 is a bottom view of the operation panel in the same mechanism, FIG. 6 is a side view of FIG. 4, and FIG. 7 is the steering regulating device. FIG. 2 is a schematic configuration diagram showing a modification example of FIG. Explanation of symbols, 11...Rear wheel, 12...Front wheel, 1
4...Tie rod, 20a...Hydraulic attachment device, 20b...Hydraulic control device, 20c...Electric control device, 30...Steering regulation device, 30a...Spacer, 30b...Operation mechanism, 30c...Regulation mechanism.

Claims (1)

[Scope of utility model registration request] A rear wheel steering regulating device for a front and rear wheel steered vehicle, comprising a front wheel steering mechanism that operates by operating a steering wheel to steer the front wheels, and a rear wheel steering mechanism that steers the rear wheels according to the driving condition of the vehicle. , the steering restriction device includes a rear wheel steering restriction means for restricting steering of the rear wheels by a predetermined value or more, a shift restriction means for restricting a shift up of the transmission by a predetermined value or more,
A rear wheel steering regulating device characterized by comprising an actuating means that activates each of these regulating means to release the speed change regulation of the transmission when the rear wheel steering is regulated.