JP2503411Y2 - Vehicle speed limiter for 4-wheel steering vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a vehicle speed limiting device for a four-wheel steering vehicle.

[Prior Art] A four-wheel steering vehicle is known (for example, Japanese Patent Laid-Open No. 59-100062).
Gazette) and an example thereof will be described with reference to FIGS.

In FIG. 3, a steering gear box 2 is connected to a steering wheel 1, and a pitman arm 3 connected to the steering gear box 2 is connected to a steering arm 4 for front wheels.

A steering unit 6 for rear steering is connected to the steering gear box 2 via a belt 5. The steering unit 6 is connected to a reserve tank 14 via a pump unit 13 driven by an engine by a hydraulic pipe (hereinafter, referred to as a pipe) L1 and a reserve tank 14 via a pipe L2. The rear axle RA is also connected by pipes L3 and L4. It is connected to a rear wheel actuator (a double-acting hydraulic cylinder in the example shown in the figure) 15 fixed to the. The steering unit 6 is switched in conjunction with the steering gear box 2 to supply and discharge hydraulic pressure to the rear wheel actuator 15.

A mode switching valve 16 is provided in the middle of the pipes L3 and L4, and the mode switching valve 16 is switched by a mode switching switch (Fig. 5) 17 to switch the flow of oil to the rear wheel actuator 15. Reverse-phase four-wheel steering mode that steers the rear wheels in the opposite phase to the front wheels (hereinafter referred to as 4WS / No1 mode), in-phase four-wheel steering mode that steers the rear wheels in the same phase as the front wheels, so-called crab running mode (hereinafter 4WS ・ No2 Mode) and two-wheel steering mode in which the rear wheels are not steered (hereinafter referred to as 2WS mode) and three steering modes.

In the hydraulic circuit diagram shown in FIG. 4, the steering unit 6 includes a 6-port 3-position switching valve 7, a reversible hydraulic motor 8 and a mechanical link 9 according to a known technique.
When the steering wheel 1 is turned to the left, for example, the switching valve 7 switches to the position I and the pipe L3 is connected.
L1 i.e. connecting to the pump unit 13 side and piping
L4 is connected to the pipe L2, that is, the reserve tank 14 side, and the hydraulic motor 8 is rotated leftward by the mechanical link 9 so that the hydraulic pressure corresponding to the steering angle of the front wheel is applied to the rear wheel actuator 15.
It is designed to be sent to. In addition, 10 is a check valve,
11 is a relief valve and 12 is a filter.

The mode switching valve 16 is a 4-port 3-position electromagnetic switching valve that switches to the parallel connection position I when the electromagnetic solenoid SOL1 is activated and switches to the 4WS / No1 mode, and the cross connection position II when the electromagnetic solenoid SOL2 is activated. Switch to 4WS ・ N
o2 mode, return when both solenoids are inactive (Pipe L3
(Connecting to the pipe L4) position to switch the running mode of the vehicle to 2WS mode respectively.

In the electric circuit diagram shown in FIG. 5, the mode changeover switch 17 is provided in parallel electric wirings (hereinafter referred to as electric wires) 1 and 12 connecting the SOL1 and SOL2 of the power supply mode changeover valve 16, respectively, and 4WS · No1 Mode switch 17a, 4WS
Switched by switch 17b for No2 mode and wire l3
Switch 17c for 2WS mode provided in parallel with 17a and 17b
The electric wires 1 to 13 are provided with pilot lamps 18a to 18c which are turned on when the electric circuit is closed.

In such a configuration, the mode selector switch 17 is used to switch the mode selector valve 16 to operate the steering wheel 1 in accordance with the 4WS / No1 mode, the 4WS / No2 mode,
It is designed to selectively operate in 2WS mode.

By the way, in this 4-wheel steering vehicle, regardless of the vehicle speed
When driving in 4WS mode, operating the steering wheel at medium and high speeds causes the vehicle to make a sharp turn (4WS / NO1 mode) or rapid traverse (4WS), unlike in 2WS mode.
・ NO2 mode) and high risk.

On the other hand, the applicant of the present invention discloses in Japanese Utility Model Laid-Open No. 61-58170 that when the auxiliary transmission of a four-wheel steering vehicle is switched between high and low,
When it is high, we are proposing a vehicle steering system that disables the 4WS mode. This proposal is effective, but it cannot prevent the above danger due to the operation of the steering wheel while driving in the medium and high speed in the 4WS mode.

Further, in Japanese Patent Laid-Open No. 61-268568, there is a 4
A technique is disclosed in which the transmission is switched to a low speed stage when the steering mode is switched to wheel steering. However, such a known technique inputs the vehicle speed and the engine speed to switch the transmission having the torque converter to the low speed side, and cannot be applied to a device having no torque converter.

Japanese Utility Model Laid-Open No. 52-82615 and Japanese Utility Model Laid-Open No. 60-84331 disclose a technique for limiting the operating range of a fuel system control lever so that a vehicle runs at a low speed. However, such a known technique limits the range of the throttle valve opening at the highest gear position or the gear shift position lower by one gear or limits the range of the engine speed, both of which are unrelated to the operation of the accelerator pedal of the driver. It cannot be forced to return to idling.

[Problem to be solved] Therefore, an object of the present invention is to provide a vehicle speed limiting device for a four-wheel steering vehicle capable of forcibly limiting the vehicle speed to a predetermined value or less regardless of the accelerator pedal operation of the driver during 4WS mode driving. There is.

[Means for Solving the Problem] According to the present invention, the pressure oil from the steering unit (6) is applied to the rear wheel actuator (15) through the mode switching valve (16), and the mode switching valve (16). In the vehicle speed limiting device for a four-wheel steering vehicle, which is switched by the mode switch (17), the mode switch (17)
The switches (17a, 17b) for the four-wheel steering mode are connected to the coil of the relay (33) via the gear position detecting means (34, 35) for detecting a gear position other than the predetermined gear, and the relay (33). ) Relay contact is connected to the solenoid (SOL3) of the switching valve (31), the driven lever (21) is fixedly installed on the accelerator control shaft (20), and the drive connected to the accelerator wire (23). A lever (22) is rotatably attached, and a spring (2) is provided between the driven lever (21) and the drive lever (22).
4) is stretched, a fluid actuating cylinder (25) is provided facing the full position of the driven lever (21), and the working end (27) of the piston rod (26) of the fluid actuating cylinder (25) is A slight gap is formed with the driven lever (21) in the full position, and the cylinder chamber (30) of the fluid operated cylinder (25) is connected to the working fluid supply source (32) via the switching valve (31). When the relay (33) operates, the switching valve (31) supplies working fluid to the cylinder chamber (30) to move the working end of the piston rod (26) to the low speed side position. ing.

[Description of Action and Effect] Therefore, when the vehicle travels in the four-wheel steering mode, the mode change switch causes the fluid to flow into the fluid actuated cylinder, and the piston rod projects so that the driven lever does not reach the full position. Then, even if the driver depresses the accelerator pedal, the drive lever moves but the driven lever does not move, and the spring only extends. In this way, the operating range of the accelerator control lever is set to the low speed side by the moving means, and as a result, the vehicle speed can be limited to the low speed range, and the danger of sudden turning or sudden traverse can be prevented.

In the present invention, as described above, the accelerator control lever has the double structure of the driv lever and the driven lever, and both are connected by the spring, so that a vehicle speed limiting device that is structurally simple and does not cause an operational overload can be obtained.

[Preferred Embodiment] In the practice of the present invention, the working fluid may be air from an existing air reservoir or pressure oil from an existing hydraulic pump. Therefore, the source of the working fluid means the air reservoir or the hydraulic pump. ing.

In carrying out the present invention, an electromagnetic switching valve is used as the switching valve, a relay is provided in the power circuit of the electromagnetic solenoid, and the relay is connected to the power source side of the mode switching switch that is the four-wheel steering mode detecting means to connect the coil to the mode switching switch. It is connected to the output side of the 4WS mode, and the circuit is provided with a gear position detection means including a select position switch and a shift switch that are closed at gear stages other than a specific gear (for example, first gear, second gear and reverse in a six gear transmission). preferable.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the parts corresponding to FIG.
The same reference numerals are given and duplicate explanations are omitted.

In FIG. 1, an accelerator control shaft (hereinafter referred to as an accelerator shaft) 20 is fixed with an acute-angled fan-shaped driven lever 21, and the accelerator shaft 20 is rotatably provided with a drive lever 22 connected to an accelerator wire 23. Installed. And this drive lever
A spring 24 is stretched between one side of the 22 (right side in the illustrated example) and the right side of the driven lever 21 facing it,
The spring 24 and both levers 21 and 22 constitute an accelerator control lever.When the accelerator pedal (not shown) is fully depressed, the accelerator wire 23 moves to the left and the accelerator lever 22 at the idling position is moved clockwise. When the accelerator lever 22 is rotated to the full position indicated by the chain line, the driven lever 21 is rotated via the spring 24 to the full position indicated by the chain line.

An air cylinder 25 is provided so as to face the full position of the driven lever 21. The working end 27 of the piston rod 26 of the air cylinder 25 forms a slight gap in the driven lever 21 in the full position, and
A spring 29 is stretched between the piston 28 and the end surface on the piston rod 26 side. And the cylinder chamber of the air cylinder 25
30 is connected to the air reservoir 32 or the atmosphere side via a switching valve 31 by an air pipe L5. Those driven levers 21, drive levers 22, springs
The moving means is constituted by 24, the air cylinder 25, the switching valve 31, the air reservoir 32 and the air pipe L5.

On the other hand, the switching valve 31 is a 3-port / 2-position electromagnetic switching valve, and its electromagnetic solenoid SOL3 is connected to the power source side of the mode switching switch 17, which is the 4WS mode detecting means, via the relay 33 via the electric wire l4. . And the relay
The coil of 33 is connected to the electric wires 1 and 12 via the electric wire l5. In the figure, 36 is an alarm buzzer. The electric wire l5 is provided with a select position switch 34 and a shift position switch 35, which are gear position detecting means. These switches 34 and 35 are closed, for example, in a vehicle equipped with a 6-speed transmission as shown in FIG. 2 when gears other than 1st gear, 2nd gear and reverse gear, that is, 3rd gear or higher in medium-high speed. It has become.

 Next, the operation will be described.

When the switch 17a or 17b of the mode changeover switch 17 is closed and the vehicle is running in the 4WS • NO1 or NO2 mode, the coil of the relay 33 is energized to close the contacts. This activates the electromagnetic solenoid SOL3 to switch the switching valve 31 to the position II and activates the alarm buzzer 36. As a result, the air in the air reservoir 32 flows into the cylinder chamber 30 of the air cylinder 25 via the pipe L5, and the air cylinder 25 extends. Then, the projecting operating end 27 moves the driven lever 21, which is, for example, the full position (shown by the chain line), to the low speed side position (shown by the solid line). Therefore, for example, even if the accelerator pedal is fully depressed, the spring 24 only extends, and the accelerator shaft 20 rotates only in a slight operating range between the accelerator shaft 20 and the operating end 27 of the driven lever 21. As a result, it is possible to securely prevent the shift to the medium to high speeds when traveling in the 4WS mode, which is safe. In the present invention, the accelerator control lever has a double structure of a drive lever 22 and a driven lever 21, an air cylinder 25 faces the driven lever 21, a switching valve 31 of an air circuit L5 has a relay 33, switches 34, 35 in an electric circuit. Since it is only provided, the structure is extremely simple.

[Effect of Device] As described above, the present invention has the following excellent effects.

(I) Since the engine speed is forcibly reduced to a low speed rotation when the vehicle is shifted to a position other than the specific gear while traveling during four-wheel steering or when the vehicle is switched to the four-wheel steering mode while traveling at a gear other than the specific gear, It doesn't take too much.

(Ii) Since the accelerator control lever has a double structure of a drive lever, a driven lever and a spring that connects the two, the operation is easy and the configuration is simple.

(Iii) It is safe in operation because the engine is forced to be in the low speed state.

[Brief description of drawings]

FIG. 1 is an air and electric circuit diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between engine speed and vehicle speed for explaining a predetermined shift stage, and FIG. 3 is an overall configuration showing a conventional four-wheel steering vehicle. 4 and 5 are hydraulic circuit diagrams, and FIG. 5 is an electric circuit diagram. 17 …… Mode selector switch, 21 …… Driven lever, 22
...... Drive lever, 24 ...... Spring, 25 ...... Air cylinder, 31 ...... Switching valve, 33 ...... Relay, 34 ...... Select position switch, 35 ...... Shift position switch

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ienaka 1-1, Daiji, Ageo City, Nissan Nissan Engineering Co., Ltd. (56) References JP 61-268568 (JP, A) JP 55-51088 (JP, B1)

Claims (1)

(57) [Scope of utility model registration request] 1. A pressure oil from a steering unit (6) is applied to a rear wheel actuator (15) through a mode switching valve (16), and the mode switching valve (16) is operated by a mode switching switch (17). In the vehicle speed limiting device for a four-wheel steering vehicle that is switched, the four-wheel steering mode switches (17a, 17b) of the mode changeover switch (17) are shift speed detecting means (34, for detecting a shift speed other than a predetermined shift speed. 35) is connected to the coil of the relay (33), the relay contact of the relay (33) is connected to the solenoid (SOL3) of the switching valve (31), and the accelerator control shaft (20)
A driven lever (21) is fixed to the drive lever (22) and is rotatably attached to an accelerator wire (23). The drive lever (22) is mounted between the driven lever (21) and the drive lever (22). The spring (24) is stretched,
A fluid operated cylinder (25) is provided so as to face the full position of the driven lever (21).
The working end (27) of the piston rod (26) of 5) forms a slight gap with the driven lever (21) in the full position, and the cylinder chamber (30) of the fluid working cylinder (25).
Is a working fluid supply source (32) through the switching valve (31).
And the switching valve (31) is connected to the relay (33).
A vehicle speed limiting device for a four-wheel steering vehicle, which supplies a working fluid to a cylinder chamber (30) to move an operating end of a piston rod (26) to a low speed side position when the engine operates.