JP2511024Y2 - 4-wheel steering vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a four-wheel steering vehicle, and more particularly to a mode switching control device thereof.

[Prior Art] Such a device is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-199572, and the applicant of the present application proposed a device for performing mode switching safely and surely in Japanese Patent Application No. 63-110621. There is.

In addition, the applicant of the present invention, in the microfilm of Japanese Patent Application No. 62-37191, a technique for determining the steering mode without returning the front and rear wheels to the neutral position when the key is turned on after the front and rear wheels are parked in a state other than the neutral position and keyed off. Is disclosed. This technique is effective, but it is a technique for determining the steering mode at the time of key-on as in the case of key-off, and does not reduce the number of steering wheel operations at the time of mode switching. And disclosed in the microfilm of Japanese Utility Model Application No. 63-14649 4
A mode detection device is described in the mode switching device of a wheel steering vehicle. However, this technique is one in which a mode detection switch is provided in a mode switching device that engages / disengages the reverse gear and the forward link with an actuator, and is not a technique for controlling the mode switching.

In a four-wheel steering vehicle in which a conventional mechanical mode switching device is switched by electronic control or the like, as shown in FIGS. 7 (a) to 7 (c), for example, from the same-phase right-turning shown in FIG. 7 (a). When switching to the reverse-phase left turning shown in FIG. 7 (c), as shown in FIG. 7 (b), the steering wheel is turned to the left and the front and rear wheels FL to RR are steered to the neutral position, and the rear wheels RL and RR are once set to the neutral position. Lock to. Then, the reverse-phase mode changeover switch is turned on to switch to the reverse-phase mode, and then the neutral lock is released and the steering wheel left turning is continued to obtain the reverse phase left turning. Looking at this from the steering amount and the lock operation, as shown in FIG. 9 (a), the steering amount is indicated by the front wheel steering angle (α ₁ + α ₂ ), and the lock and unlock operations are performed at the neutral position indicated by the chain line. Need.

In addition, as shown in FIGS. 8 (a) to 8 (c),
When switching from the in-phase right cut shown in Fig. 8 (a) to the reverse phase right cut shown in Fig. 8 (c), the reverse-phase mode switch is turned on, the common-mode switch valve is turned off, and the reverse-phase switch valve is turned off.
When the steering wheel is turned to the left, only the front wheels FL and FR are steered as shown by the solid line in FIG. 8 (b), and the reverse phase mode switching is completed when the reverse phase gear meshes. Then, the eighth
The front wheels FL and FR are cut to the right as shown by the solid line in FIG. 7C (at the same time, the rear wheels RL and RR are cut to the left as shown by the solid line) to obtain the antiphase right cut. When this is seen from the steering amount, as shown in FIG. 9 (b), the steering amount is the front wheel steering angle (α ₁
As shown by + α ₃ ) × 2, there are extra operations on the left and right turns of the steering wheel.

As described above, the neutral lock and release of the rear wheels and the extra handle operation are required, which is a burden on the driver.

[Problem to be Solved by the Invention] Therefore, the present invention provides a four-wheel steering vehicle that can reduce the driver's operation during steering mode switching between the in-phase mode and the anti-phase mode as much as possible. Has an aim.

[Means for Solving the Problems] According to the present invention, a mode switching gear box, a position sensor for detecting a steering mode, a mode switching switch, a steering angle sensor for detecting a steering angle of rear wheels, and a neutral lock. In a four-wheel steering vehicle including a lock sensor that detects a lock and a lock release valve that releases a neutral lock, steering is performed by being connected to the position sensor, the lock sensor, the mode changeover switch, and a ROM storing a set value. Drive for controlling a control circuit that outputs a control signal for mode switching when the rear wheel steering angle enters a set range at the time of mode switching and a mode switching valve that operates the lock release valve and the mode switching actuator by signals of the control circuit And a control unit including a circuit.

And the above setting range is 2 ° to both sides from the neutral position.
20 ° is desirable, but about 5 ° is preferable as the set value.

[Operation] In the four-wheel steering vehicle configured as described above, for example, when in-phase right-turning is switched to reverse-phase, when the reverse-phase mode switch is turned on and the steering wheel is turned left, the control circuit causes the rear steering angle to change. Based on the signal from the sensor, it is determined whether or not the rear wheel steering angle has reached the set value. When the set value is reached, the drive circuit turns off the in-phase mode switching valve and turns on the anti-phase mode valve.
N, and switch the mode. As a result, only the front wheels are steered to the left, and the reverse phase gear meshes at a steering angle smaller than that of the conventional case, and the reverse phase mode is established. If the steering wheel is further turned to the left from this state, the same amount of front-wheel steering as before is used to complete reverse-phase left-turning from in-phase right-turning, which is the same as the conventional method. No operation is required.

When the steering wheel is turned to the right to the same front wheel right steering angle as in the conventional case from the state of the above-mentioned reverse phase mode confirmation, the reverse phase right turning from the same phase right cutting as in the conventional case is completed. Since the left front wheel steering angle when the mode is set is smaller than the conventional value, the total steering amount is significantly smaller than the conventional value.

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

In FIG. 1, one end of a front pitman arm 23 of a gear box 22 fixed to a frame and connected to a steering wheel 21 has a front drag ring 24.
A front tie rod arm 26 integrally formed with the front steering arm 25 is connected to a front tie rod arm 26 on the other side via a front tie rod 27.

The other end of the front pickman arm 23 is
The idler link 28 and the first idler lever 29 are connected to the input side of a mode switching gear box 50 fixed to the frame. The output side of the mode switching gearbox 50 is a torque tube bracket fixed to the frame.
It is connected to one end of a torque tube 31 rotatably supported by 30. A rear pitman arm 33 is fixed to the other end of the torque tube 31, and the rear pitman arm 33 is pivotally mounted via a rear pitman link 34 to an actuator bracket 36 whose one end is fixed to the frame. It is connected to the steering actuator 35. The other end of the rear steering actuator 35 is connected to the middle of a second idler lever 38 pivotally attached to a second idler lever bracket 37 fixed to the frame, and the end portion of the second idler lever 38 is a rear drag. It is connected to a rear steering arm 40 via a link 39. The rear tie rod arm 41 formed integrally with the rear steering arm 40 is connected to the rear tie rod arm 41 on the other side via a rear tie rod 42.

In the mode switching gear box 50, an input side bevel gear and an output side bevel gear having a diameter larger than that of the bevel gear are provided on the same axis, and a planetary gear that meshes with both bevel gears is connected to the input side bevel gear via a gear arm. It is rotatably supported on the shaft part of. Further, there is provided a mode switching actuator 51 including a mode switching in-phase actuator that operates a clutch that connects and disconnects both bevel gears, and a mode switching anti-phase actuator that locks rotation of the gear arm.

With this configuration, in the in-phase mode of four-wheel steering (4WS), the mode switching in-phase actuator is extended and the clutch is moved to connect both bevel gears. Therefore, the rotation of the first idler lever 29 is directly transmitted from the rear pitman arm 33 to the rear wheels, and the in-phase steering angle characteristic in which the front wheel steering angle and the rear wheel steering angle are equal is obtained.

In the reverse phase mode, the clutch is disengaged to extend the mode switching reverse phase actuator to fix the gear arm and lock the rotation. Therefore, the rotation of the first idler lever 29 is transmitted from the input-side bevel gear to the output-side bevel gear, which has a larger diameter than the input-side bevel gear, through the planetary gear in a reverse and decelerated manner, and the rear wheel steering angle is greater than the front wheel steering angle. A small reverse phase mode characteristic can be obtained.

For two-wheel steering (2WS), both actuators are turned off,
One of the rear steering systems is fixed by a neutral lock device according to a known technique to lock the rear wheels in a neutral position.

The mode switching reverse-phase actuator, the reverse-phase mode switching valve 15 which is a mode switching actuator control means for operating the same-phase actuator, and the common-mode switching valve 16
Is connected to a pneumatic pressure source A, and the air release source A is connected to a lock release air cylinder 1 via a lock release valve 14 which is a neutral lock release means. Further, the rear steering actuator 35 is connected to the hydraulic power source B.

The mode switching actuator 51 is provided with an in-phase position sensor 3, a 2WS position sensor 4 and an anti-phase position sensor 5, which are mode detecting means, and are connected to the control unit 20, respectively.

The control unit 20 includes a rear steering angle sensor 2 which is a rear wheel steering angle detecting means provided on the rear pitman arm 33, and first and second neutral lock detecting means which are provided on the unlocking air cylinder 1. Lock sensor 6, 7,
The air pressure sensor 8 of the air pressure source A and the display unit 52 are connected to each other, and the display unit 52 includes a reverse phase mode changeover switch 53a, a 2WS mode changeover switch 53b and an in-phase mode changeover switch 53c each having a built-in mode indicator. It is provided.

In FIG. 2, the control unit 20 is composed of a microcomputer, an A / D converter 20d to which the rear steering angle sensor 2 is connected, the converter 20d, and a position sensor 3
To 5, lock sensors 6 and 7, and mode selector switch 53a
To 53c are connected to the control circuit 20a, and a ROM 20c and a drive circuit 20b connected to the circuit 20a are provided.
b includes lock release valve 14 and reverse-phase mode switching valve 15
And the in-phase mode switching valve 16 are connected. The ROM 20c stores a preferable set value δ _RR (for example, about 5 °) in a set range (for example, 2 ° to 20 ° on both sides from the neutral position).

Next, the control mode will be described mainly with reference to FIG.
Note that FIG. 3 shows the control for switching the 2WS mode or the in-phase mode to the in-phase mode, and the parentheses in the sentence in the drawing show the control for switching the 2WS mode or the in-phase mode to the in-phase mode.

Now, when the reverse-phase mode switch is turned on and the handle is operated, the control unit 20 determines whether or not the 2WS mode flag is set in the control circuit 20a, that is, whether or not the 2WS mode is set (step
S ₁ ). You were YES, the output control signal from the drive circuit 20b, and turns OFF the common mode switching valve 16 (Step S _2),
Performing switching operation in the reverse phase mode reverse phase mode switching valve 15 to ON (Step S _3). Then, reverse phase and the gear meshes determines whether reverse phase position sensor 5 is ON (step S _9), if NO, the process returns, you were YES, signals from the lock sensor 6 It is determined whether or not the lock is released based on the
S ₁₀ ). In the case of NO, the control signal is output from the drive circuit 20b, the lock release valve 14 is turned on, and the lock release cylinder 1
Actuated and to release the lock (step S _11), and return, you were YES, the determined reverse phase mode, the reverse-phase mode indicator lit (step S _12), the process returns.

Further, when step S ₁ is NO, that is, FIG. 4 (a)
In the common mode, for example, when the steering wheel is turned left and the steering wheel is turned left, the control circuit
It determines whether A / D converter 20d is abnormal at 20a (step S _4). If YES, return, and if NO,
It is determined whether or not the rear steering angle sensor 2 is abnormal (step S ₅ ). If YES, the process returns, and if NO, the rear wheel steering angle δ _R of the rear wheel steering angle δ _R is determined based on the signal from the rear steering angle sensor. absolute value determines whether it is smaller than the set value [delta] _RR (about 5 °) that is stored in the ROM 20c (step S _6). YES
If so, that is, as shown in FIG. 4 (b), the front and rear wheels FL
~RR is in state or in the neutral position before the state shown by the solid line, and outputs a control signal from the drive circuit 20b, and turns OFF the common mode switching valve 16 (step S _7), and ON the reverse phase mode switching valve 15, Perform mode switching operation (step
S _8), the procedure proceeds to step S _9. Then, as the steering wheel operation continues, as shown in FIG. 4 (c), only the front wheels FL, FR are steered, and the reverse operation is performed at the front wheel steering angle α ₄ smaller than the front wheel steering angle α ₂ shown in FIG. 7 (c). phase gear meshes (step S _9), reverse-phase mode is determined (step S _12). Therefore, the locking operation of the rear wheels is unnecessary. When the steering wheel is further turned to the left from this state, as shown in FIG.
The RR is steered from the chain line position to the solid line position, and at the front wheel steering angle α ₂ , the in-phase right-turn from the in-phase right-turn is completed. Therefore, as shown in FIG. 6 (a), the steering amount is the front wheel steering angle (α ₁ +
α ₂ ), which is equal to the front wheel steering angle (α ₁ + α ₂ ) of the conventional steering amount shown in FIG. 9A, but the operation of locking and unlocking the rear wheels at the neutral position shown by the chain line is unnecessary.

Further, when the steering wheel is turned to the right from the state of FIG. 4 (c), the front and rear wheels FL to RR are steered from the chain line position to the solid line position as shown in FIG. 5 (b), and in-phase at the front wheel steering angle α ₁ . Reverse phase right cut from right cut is completed. Thus, as shown in FIG. 6 (b), the steering amount is the front wheel steering angle _{(α 1 + α 4) ×} 2 , and the front wheel steering angle of the conventional steering amount shown in FIG. 9 (b) (α ₁ +
Significantly smaller due to α ₃ ) × 2.

[Advantages of the Invention] Since the present invention is configured as described above,
For example, when operating the mode selector switch to switch from in-phase right cut to reverse-phase left cut, it is possible to switch without performing the conventional neutral lock and unlock operations of the rear wheels. When switching from to reverse-phase right-turning, when the rear-wheel steering angle becomes equal to or less than the set value, mode switching is performed and the reverse-phase mode is established, so steering operation is significantly reduced.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a control block diagram, FIG. 3 is a control flowchart diagram, and FIG.
Figures (a) to 4 (c) are drawings for explaining the behavior of the front and rear wheels from right-turning in the same phase to determination of the reverse phase mode, and Figures 5 (a) and 5 (b) after the determination of the reverse phase mode. Drawings explaining the behavior of the front and rear wheels until the completion of the opposite-phase left cutting and the opposite-phase right cutting, FIGS. 6 (a) and 6 (b) are from the in-phase right cutting to the opposite-phase left cutting and the opposite-phase right cutting completion. FIGS. 7 (a) to 7 (c) are drawings for explaining the steering amount of the conventional 4
Drawings corresponding to FIGS. 4 (a) to 4 (c) and 5 (a) of a wheel steering vehicle, and FIGS. 8 (a) to 8 (c) are drawings of a conventional four-wheel steering vehicle. Drawings corresponding to Figs. 4 (a) to 4 (c) and 5 (b), Fig. 9 (a)
And FIG. 9 (b) is a drawing corresponding to FIG. 6 (a) and FIG. 6 (b) of the conventional four-wheel steering vehicle. 2 ... Rear rudder angle sensor, 3 ... in-phase position sensor,
4 ... 2WS position sensor, 5 ... reverse-phase position sensor, 6 ... first lock sensor, 7 ... second lock sensor, 14 ... lock release valve, 15 ... reverse-phase mode switching valve, 16 ... In-phase mode switching valve, 20 ... Control unit, 50 ... Mode switching gear box, 51 ... Mode switching actuator, 53a ... Reverse-phase mode switching switch, 53b ... 2WS switching switch, 53c ... In-phase mode switching switch

Claims (1)

(57) [Scope of utility model registration request] 1. A mode switching gear box (50), a position sensor (3 to 5) for detecting a steering mode, a mode switching switch (53a to 55a), and a steering angle sensor (for detecting a steering angle of rear wheels). 2), a lock sensor (6, 7) for detecting the neutral lock, and a lock release valve (14) for releasing the neutral lock, the position sensor (3-5) and the lock Control signals for mode switching when the rear wheel steering angle is within the setting range when the steering mode is switched by being connected to the sensors (6, 7), the mode switching switches (53a to 55a) and the ROM (20c) storing the set values. And a drive circuit for controlling a mode switching valve (15, 16) for operating the lock release valve (14) and the mode switching actuator (51) by a signal from the control circuit (20a). (20b) and Four-wheel steering vehicle, characterized in that a control unit (20) having a.