JPH0328206Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a hydrostatic hydraulic drive device for a hydraulically driven vehicle.

BACKGROUND ART Conventional hydrostatic drive systems of this type cannot be warmed up when the vehicle is stopped.

That is, in Fig. 3, by depressing the brake pedal 1 and operating the speed control lever 2, a hydrostatic hydraulic drive pump (hereinafter referred to as a hydraulic pump) 3 and a hydrostatic hydraulic drive motor (hereinafter referred to as a hydraulic motor) are operated. ) 4, but when the brake pedal 1 is depressed, the swash plates of the hydraulic pump 3 and hydraulic motor 4 are returned to neutral and the speed control lever 2 can be operated. However, the swash plate did not move and there was no discharge from the hydraulic pump 3, so the oil in the hydrostatic hydraulic drive circuit was not moving.

Problems to be solved by the invention Due to the structure that does not allow warm-up operation as described above, the resistance torque due to the oil viscosity of the hydrostatic hydraulic drive circuit during cold start is large, making it difficult to start the engine. Due to the viscosity of the oil, the movement of the bobarp and other parts did not work smoothly, causing abnormalities such as bending and turning in the vehicle's movement.

Furthermore, if work is suddenly started at low temperatures, the viscosity of the oil may cause poor lubrication, or the throttling resistance may cause an abnormal load to be applied, leading to damage to the interior of the hydrostatic hydraulic drive device.

The present invention was developed in view of the above circumstances, and its purpose is to make it possible to warm up the vehicle while the vehicle is stopped, reduce the resistance torque due to oil viscosity, and make it easier to start the engine. The object of the present invention is to provide a hydrostatic hydraulic drive device for a hydraulically driven vehicle without fear of internal damage.

Means and operation for solving the problem The present invention inputs signals from the potentiometer 27 of the speed control lever 26 and the potentiometer 25 of the brake pedal 24, and controls the speed control lever. 25 to a certain vehicle speed, the swash plate angle of the hydrostatic hydraulic drive pump and motor can be obtained to match that vehicle speed, and in this state, when the brake pedal 24 is depressed, the pump and motor The swash plate angle of the pump and motor is controlled in the direction of decreasing vehicle speed, and when the brake pedal 24 is depressed, the swash plate angle of the pump and motor is
The computer 28 outputs a control signal that causes the brake pedals 9 and 31 to return to neutral, and has a normal operating position and a warm-up operating position. A warm-up command switch 37 that cancels the control signal from the computer 28 to return the swash plates 29, 31 to neutral, and a lock mechanism 33 that fixes the brake pedal 24 when the brake pedal 24 is depressed.
and a warning circuit A that issues a warning when the warm-up command switch 37 is switched to the warm-up operation position without the brake pedal 24 being fixed. When the brake pedal 24 is locked by the mechanism 33, by switching the warm-up command switch 37 to the warm-up operation side, the pump output from the computer 28 when the brake pedal 24 is operated is controlled. The swash plate neutral signal for returning the motor swash plates 29, 31 to neutral is canceled. Therefore, even when the brake pedal 24 is locked, that is, when the vehicle is parked, the swash plate angles of the hydraulic pump and motor can be controlled by operating the speed control lever 26. Brake
If the warm-up command switch 37 is switched to the warm-up position A without locking the key pedal 24, a warning circuit A will issue a warning.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

10 is a static pressure type hydraulically driven pump (hereinafter referred to as a hydraulic pump), and a port 10a of the hydraulic pump 10
is connected to a port 12a of a hydrostatic hydraulic drive motor (hereinafter referred to as hydraulic motor) 12 via a pipe 11, and a port 10b of the hydraulic pump 10 is connected to a port 12a of a hydrostatic hydraulic drive motor (hereinafter referred to as a hydraulic motor).
3 to the port 12b of the hydraulic motor 12. Both conduits 11 and 13 are connected via a neutral bypass valve 14, and the output shaft 15 of the hydraulic motor 12 is connected via a brake 16 to the final and suspension parts.

17 is a servo pump;
The discharge side of the brake valve 19 is connected to the port 19a of the brake valve 19 via a pipe 18, and the port 19b of the brake valve 19 is connected to the neutral bypass valve 14 via a pipe 20. The port 19b of the brake valve 19 is connected to the oil chamber 22 of the brake 16 via a conduit 21.

The spool 23 of the brake valve 19 is connected to a brake pedal 24, and a potentiometer 25 is provided at the rotating portion of the brake pedal 24.

26 is a speed control lever, and a potentiometer 27 is provided at the rotating portion of the speed control lever 26.

Potentiometers 25 and 27 are computer 2
The output side of the computer 28 is connected to the electromagnetic proportional control valve 30 of the swash plate 29 of the hydraulic pump 10 and the electromagnetic proportional control valve 32 of the swash plate 31 of the hydraulic motor 12, respectively. It has been done.

33 is a locking mechanism for the brake pedal 24, and the locking mechanism 33 includes a lock lever 34 and a lock arm 35 operated by the lock lever 34.

36 is a lock detection switch, and 37 is a warm-up command switch. In FIG. 2, a contact a of a lock detection switch 36 is connected to a power source 38 via a pilot lamp 39 and a warning buzzer 40, and these constitute a warning circuit A. Contact b of the lock detection switch 36 is connected to the input side of the computer 28 via a lead wire 41. The contact c of the lock detection switch 36 is connected to the contact e of the warm-up command switch 37 via a lead wire 43, and the contact d of the warm-up command switch 37 is connected to the contact e of the warm-up command switch 37 via a lead wire 42. - is connected to the input side of the converter 28. Furthermore, the contact f of the warm-up command switch 37 is connected to the solenoid 44 of the brake valve 19, and the other contact g is grounded.

When the brake pedal 24 is depressed, the lock detection switch 36 is turned on and the contact piece c comes into contact with the contact point b. Further, by switching the warm-up command switch 37 to the warm-up position a, the contact piece d is opened, and the contact piece g is brought into contact with the contact point e.

Next, the operation will be explained.

The capacity of the hydraulic pump 10 and the hydraulic motor 12 is controlled by controlling the swash plate angle of the hydraulic pump 10 and the hydraulic motor 12 via the electromagnetic proportional control valves 30 and 32 in response to an electric signal from the computer 28. It will be done.

Electric signals for capacity control are sent to the potentiometer 27 of the speed control lever 26 and the brake.
A signal from the potentiometer 25 of the key pedal 24 is input and output from the computer 28, and when the speed control lever 26 is set to a certain vehicle speed, a swash plate angle suitable for that vehicle speed can be obtained.
Furthermore, when the brake pedal 24 is depressed, the swash plate 29 returns to neutral due to an electric signal and the hydraulic pump 1
It is designed not to output from 0.

When the brake pedal 24 is depressed, the oil pumped from the servo pump 17 escapes to the tank 45 by switching the brake valve 19, and at the same time, the oil in the brake chamber 22 also flows to the tank 45, causing the brake 16 to be activated. Operate. Further, the neutral bypass valve 17 also becomes open, and the swash plate 29 returns to its neutral position.

Now, when the brake pedal 24 is depressed and the lock mechanism 33 locks the brake pedal 24, the lock detection switch 36 is activated and the contact piece c is turned on.
touches contact b.

At this time, when the warm-up command switch 37 is switched to the warm-up position A side, the brake valve 19 is
The contact piece d connected to the solenoid 44 is opened, and the brake operation signal input from the solenoid 44 to the computer 28 is cut off, and the contact g contacts the contact e, and the ground signal is detected to be locked. The control signal is input to the computer 28 through the contact c and the contact b of the switch 36, and cancels the control signal of the computer 28 for returning the swash plates 29, 31 to neutral when the brake pedal 24 is depressed.

Therefore, even in this state, that is, in a parked state with the brakes applied, the speed control lever cannot be moved.
26, the swash plates 29 and 31 of the hydraulic pump 10 and the hydraulic motor 12 are operated via the computer 28, and the hydraulic pump 1
Pressure oil is discharged from 0. At this time, the neutral bypass valve 14 is in the bypass position due to the action of the spring 14a, so the oil discharged from the hydraulic pump 10 is circulated through the neutral bypass valve 14 and heated.

On the other hand, if the warm-up command switch 37 is switched to the warm-up operation position A without locking the brake pedal 24, the ground signal from the contact g flows to the warning circuit A via the contact c, and the pilot lamp 39 lights up. At the same time, the warning buzzer 40 sounds.

[Effect of idea]

Since the present invention is as described above, the brake pedal 24 is depressed to lock it by the lock mechanism 33, and then the warm-up command switch 37 is activated.
By switching to the warm-up operation position A side, the hydraulic pump 10 and hydraulic motor 12, which were output via the computer 28 in response to the brake activation signal, are
The control signal is canceled to return the swash plate angle to neutral. Therefore, even when the brake is applied, the swash plate angles of the hydraulic pump 10 and the hydraulic motor 12 can be controlled by operating the speed control lever 26, and as a result, even when the vehicle is parked, the hydraulic oil is supplied to the hydraulic pump 10. It is possible to perform a so-called warm-up operation in which the hydraulic fluid is discharged from the hydraulic fluid and circulated within the static pressure circuit, and it is possible to raise the temperature of the hydraulic fluid and reduce its viscosity prior to continuous operation.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, FIG. 2 is an electric circuit diagram, and FIG. 3 is an explanatory diagram of the configuration of a conventional hydrostatic hydraulic drive device for a hydraulically driven vehicle. 28 is a computer, 33 is a lock mechanism, 37
is the warm air switch.

Claims (1)

[Scope of utility model registration request] The signal from the potentiometer 27 of the speed control lever 26 and the potentiometer 25 of the brake pedal 24 is input, and when the speed control lever 26 is set to a certain vehicle speed, it is determined whether the speed matches the vehicle speed. Hydrostatic hydraulic drive pumps and motors
In this state, when the brake pedal 24 is depressed, the swash plate angle of the pump and motor is controlled in a direction that reduces the vehicle speed, and when the brake pedal 24 is depressed, a computer that outputs a control signal that causes the swash plates 29, 31 of the pump and motor to return to neutral when
The swash plate 29, 3 has a normal operation position and a warm-up operation position, and by switching to the warm-up operation position, the swash plate 29, 3 is operated by pressing the brake pedal 24.
a warm-up command switch 37 for canceling the control signal of the computer 28 for returning the controller 1 to neutral;
A lock mechanism 33 that fixes the brake pedal 24 when the brake pedal 24 is depressed, and
Warm-up command switch 37 without fixing pedal 24
A hydrostatic hydraulic drive device for a hydraulically driven vehicle, characterized in that it is equipped with a warning circuit A that issues a warning when the switch is switched to a warm-up operation position.