JPH0448328Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a hydraulic circuit for running a ski slope maintenance vehicle or a snowmobile hydraulically driven vehicle.

(Prior art) In a ski slope maintenance vehicle as shown in Fig. 3,
Conventionally, a hydraulic circuit for traveling as shown in FIG. 2, for example, has been provided.

In FIG. 2, the power of the engine 1 is transmitted to the left and right variable displacement pump assemblies 301, 331 via the transfer reducer 2. In the variable displacement pump assemblies 301 and 331, the electromagnetic proportional solenoid valves 304 and 334 are operated by a control command current from the controller.

Pressure oil from the charge pumps 303, 333 (located coaxially with the variable displacement pumps 301, 331) is sent to the servo cylinders 305, 335 to displace the swash plates of the variable displacement pumps 302, 332, but at the same time The electromagnetic proportional solenoid valves 304 and 334 are the feed back levers 30.
8,338, it is displaced to the commanded position and stopped.
Pressure oil from the variable displacement pump 302, 332 is sent to the variable displacement piston motor 501, 531 through the piping 11 or 12, 21 or 22 to drive the motor 501, 531, and further to the final reduction gear 601, 631. The power is transmitted to the sprockets 701, 731 via the crawler tracks 801, 83.
Drive 1.

Therefore, the electromagnetic proportional solenoid valve 304,3
34 malfunctions, it becomes impossible to supply pressure oil to the variable displacement piston pumps 302, 332, and the vehicle becomes unable to travel.

(Problems to be solved by the invention) The conventional techniques described above have the following problems.

(1) Dust or other foreign matter gets into the electromagnetic proportional solenoid valve, causing malfunction of the valve itself.

(2) The coil of the electromagnetic proportional solenoid valve is disconnected due to vehicle vibration, etc.

(3) The circuit through which the pilot hydraulic pressure from the electromagnetic proportional solenoid valve is sent to the servo cylinder is blocked by debris, and the servo cylinder piston does not operate, making the vehicle unable to run.

(Means for solving the problem) As shown in FIG. 1, the electromagnetic switching valves 402 or 403 and 404 are
(The other one is 432 or 433 and 434) constitutes a hydraulic circuit in which pressure oil can be sent directly to the swash plate control servo cylinders 305, 335.

(Function) During normal operation, the variable displacement pumps 302, 3
The pressure oil of 32 is connected to the variable displacement piston motor 501, 5.
31 to drive the vehicle. The pressure oil of the charge pumps 303, 333 is supplied to the servo cylinder 30 via electromagnetic proportional solenoid valves 304, 334.
5,335 to control the swash plate angle, ie, the discharge amount, of the variable displacement pump.

In an emergency, pressure oil from the charge pump enters the servo cylinders 305, 335 via the electromagnetic switching valve assemblies 401, 431, displacing the swash plates of the variable displacement pumps 302, 332.

(Example) In FIGS. 1 and 3, 1 is an engine, 2 is a transfer reducer, 3 is a tank, 301, 33
1 is variable displacement pump assembly, 302, 332
is a variable displacement pump, 303, 333 is a charge pump, 304, 334 is an electromagnetic proportional solenoid valve, 305, 335 is a servo cylinder, 306,
307, 336, 337 are relief valves, 30
8,338 is a feedback lever, 401,4
31 is an emergency circuit, 402 and 432 are electromagnetic switching valves, 403 and 433 are electromagnetic switching valves, 40
4,434 is an electromagnetic switching valve, 501,531 is a variable displacement piston motor, 601,631 is a final reduction gear, 701,731 is a sprocket,
801, 831 are crawler tracks, 11, 12, 21, 22
is a pipe, 13, 23 is a pipe, 14, 15, 24,
25 is a conduit, and 16 and 26 are conduits.

Driven by the engine 1, power is transmitted to the left and right variable displacement pump assemblies 301, 331 via the transfer reducer 2.

In the variable displacement pump assemblies 301 and 331, the electromagnetic proportional solenoid valves 304 and 334 are operated by a control command current from the controller. Pressure oil from the charge pumps 303, 333 (located on the same axis as the variable displacement pumps 301, 331) is sent to the servo cylinders 305, 335 to displace the swash plates of the variable displacement pumps 302, 332, but at the same time the electromagnetic proportional solenoid valve 304 ,3
34 is displaced to the commanded position by the feedback levers 308 and 338 and then stopped. The pressure oil from the variable displacement pumps 302, 332 is sent to the variable displacement piston motors 501, 531 through the pipes 11, 12, 21, or 22, and the motors are driven. Power is transmitted to sprockets 701, 731 to drive crawler tracks 801, 831.

In addition, in an emergency, the control current from the controller is transmitted to the electromagnetic switching valve 403 of the emergency circuit 401, 431.
and 404,433 and 434,402 and 404,4
32 and 434 at the same time, the pressure oil of the charge pumps 303 and 333 passes through the pipes 13 and 23,
(When the electromagnetic valves 403, 433 are at high pressure, the electromagnetic valves 402, 432 drain.) High pressure oil passes through the pipes 15, 25 to the servo cylinder 305,
335 and variable displacement pumps 302, 33
Displace the swash plate No.2. (However, since there is no feedback mechanism at this time, the swash plate angle will be displaced to the maximum tilt of the variable displacement pump.) (Effect of the invention) In the drive system of electronically controlled ski slope maintenance vehicles, the electronic circuit Although it is often impossible to run due to an abnormality or an abnormality in the solenoid valve, by receiving the emergency circuit of this invention, it becomes possible to run on your own even in an emergency.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the emergency hydraulic circuit of the hydraulically driven vehicle of the present invention, and FIG. 2 shows a conventional hydraulic circuit diagram for traveling. FIG. 3 is a side view of the ski slope maintenance vehicle. 1...Engine, 2...Transfer reducer,
3...Tank, 301,331...Variable capacity pump assembly, 302,332...Variable capacity pump, 303,333...Charge pump, 30
4,334...Electromagnetic proportional solenoid valve, 30
5,335... Servo cylinder 306, 307,
336,337...Relief valve, 308,3
38...Feedback lever, 401,431
...Emergency circuit, 402,432...Solenoid switching valve, 403,433...Solenoid switching valve, 40
4,434...Solenoid switching valve, 501,531
...Variable displacement piston motor.

Claims (1)

[Scope of utility model registration request] The electromagnetic proportional solenoid valves 304 and 334 are operated by the control command current from the controller,
By the pilot oil pressure of the electromagnetic proportional solenoid valve, the pistons of the servo cylinders 305, 335 that control the swash plate angles of the variable displacement pumps 302, 332 are displaced to command positions, and the amount of oil proportional to the command current is transferred to the variable displacement pistons. Motor 501, 531
In the hydraulic circuit for supplying water to the
03,333 pressure oil to emergency circuit 401,431
The electromagnetic switching valves 402 or 403, and 404, are connected to the control command current from the controller.
432, 433, and 434 are operated to supply the pressure oil of the charge pumps 303, 333 to the servo cylinders 305, 335, and the variable displacement pump 30
An emergency hydraulic circuit for a hydraulically driven vehicle, characterized in that pressure oil from variable displacement pumps 302, 332 is fed to variable displacement piston motors 501, 531 by displacing a swash plate No. 2,332.