JP2689256B2 - Driving control method for hydraulically driven vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a travel control method for a hydraulically driven vehicle that drives a variable motor with discharge pressure oil of a variable pump and rotationally drives traveling wheels with the variable motor. .

[Conventional technology]

The discharge pressure oil of the variable pump with both swings that can change the capacity and the discharge direction is supplied to the variable motor with both swings that can change the capacity and the rotation direction to drive the variable motor, and thereby the driving wheels are rotated. Hydraulic drive in which the displacement changing member of the variable pump is controlled by the pump servo mechanism, the displacement control member of the variable motor is controlled by the motor servo mechanism, and a control signal is input from the controller to the pump servo mechanism and the motor servo mechanism. The car is known.

In such a hydraulically driven vehicle, when the vehicle speed is zero, that is, when the vehicle is stopped, the capacity control member of the variable motor is set to the capacity zero state, and when the vehicle starts, the capacity control member is switched to the maximum capacity state. Driving is controlled.

[Problems to be solved by the invention]

According to such a traveling control method for a hydraulically driven vehicle, there is a slight time delay, for example, 0.2 seconds, during which the capacity control member switches from the zero capacity state to the maximum capacity state. It may be rotated by external force.

For this reason, when the vehicle is started from a sloping ground, the variable motor is rotated by the weight of the vehicle, which may cause the vehicle to slip off the sloping ground, which is unpreferable to the operator.

Therefore, it is an object of the present invention to provide a travel control method for a hydraulically driven vehicle that prevents the vehicle from slipping off when starting from a sloping ground.

[Means and actions for solving the problem]

The present invention supplies the discharge pressure oil of the variable pump 1 of both swings capable of varying the capacity and the discharge direction to the variable motor 3 of both swings capable of varying the capacity and the rotation direction to drive the variable motor 3.
Thereby, the traveling wheels 4 are rotationally driven, the displacement control member of the variable pump 1 is controlled by the pump servo mechanism 7, the displacement control member of the variable motor 3 is controlled by the motor servo mechanism 9, and the pump servo mechanism 7, In a hydraulically driven vehicle in which a control signal is input to the motor servo mechanism 9 from the controller 10 and the displacement control member of the variable motor is brought to a state of zero displacement when the vehicle is stopped, the controller 10 is controlled by the controller 10 to set a vehicle inclination angle equal to or larger than a set value. Is input, the parking brake is released after the capacity control member of the variable motor 3 is set to the maximum capacity state,
When a start signal and a vehicle inclination angle equal to or less than a set value are input to the controller 10, the parking brake is immediately released and the capacity control member of the variable motor 3 is operated in the capacity increasing direction. Is a travel control method for a hydraulically driven vehicle.

According to the present invention, when the vehicle starts on a sloping ground, the parking brake is released after the capacity of the variable motor 3 reaches the maximum capacity state. Becomes rotatable and the traveling wheel 4 is braked by the parking brake until the capacity control member of the variable motor 3 switches from zero capacity to the maximum capacity state. As a result, the vehicle does not slide down when starting on a slope.

〔Example〕

As shown in FIG. 1, the discharge port 1a of the double swing variable pump 1 is connected to the inlet port 3a of the double swing variable motor 3 through the conduit 2.
The output side of the variable motor 3 is connected to the traveling wheels 4, and the traveling wheels 4 can be braked by the parking brake 5.

The displacement control member of the variable pump 1, for example, the swash plate 6, is controlled by the pump servo mechanism 7, and the displacement control member of the variable motor 3, for example, the swash plate 8, is controlled by the motor servo mechanism 9, and the pump and motor A control signal is input to the servo mechanisms 7 and 9 from the controller 10 and the controller
A travel signal is input from a travel lever 11 to the vehicle 10, and a vehicle inclination angle is input from an inclinometer 12 to the vehicle 10.

The controller 10 outputs a maximum capacity signal to the motor servo mechanism 9 when a start signal is input from the traveling lever 11 when a set angle, for example, 5 ° or more is input from the inclinometer 12, and the swash plate 8 is output. Is set to the maximum angle, that is, the maximum capacity state, and then the brake release signal is output to the parking brake 5, and when the angle less than the set angle is input from the inclinometer 12, the start signal is input from the traveling lever 11. Immediately after that, a brake release signal is output to the parking brake 5.

That is, the controller 10 outputs the operation control signal based on the flowchart shown in FIG.

〔The invention's effect〕

When the vehicle starts on a sloping ground, the parking brake is released after the capacity of the variable motor 3 reaches the maximum capacity state.
Becomes rotatable and the traveling wheel 4 is braked by the parking brake until the capacity control member of the variable motor 3 switches from zero capacity to the maximum capacity state. As a result, the vehicle does not slide down when starting on a slope.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of an apparatus for carrying out the method according to the present invention, and FIG. 2 is a flowchart of control operation. 1 is a variable pump, 3 is a variable motor, 4 is a traveling wheel, 7 is a pump servo mechanism, 9 is a motor servo mechanism, and 10 is a controller.

Claims (1)

(57) [Claims] Claims: 1. Discharge pressure oil of a two-way swing variable pump 1 capable of changing the capacity and discharge direction is supplied to a two-way swing variable motor 3 capable of changing the capacity and rotation direction to drive the variable motor 3.
Thereby, the traveling wheels 4 are driven to rotate, the displacement control member of the variable pump 1 is controlled by the pump servo mechanism 7, the displacement control member of the variable motor 3 is controlled by the motor servo mechanism 9, and the pump servo mechanism 7, In a hydraulically driven vehicle in which a control signal is input to the motor servo mechanism 9 from the controller 10 and the displacement control member of the variable motor is brought to a state of zero displacement when the vehicle is stopped, the controller 10 is controlled by the controller 10 to set a vehicle inclination angle equal to or larger than a set value. Is input, the parking brake is released after the capacity control member of the variable motor 3 is set to the maximum capacity state, and when the start signal and the vehicle inclination angle less than the set value are input to the controller 10, the parking brake is immediately released. And the capacity control member of the variable motor 3 is operated in the capacity increasing direction. Control method.