JPH0537551U - Control device for hydraulic drive vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure that the vehicle can be stopped by depressing the brake pedal. [Structure] Electric motor 6 for increasing / decreasing the rotational speed of engine 1
An engine governor 7, a variable cylinder 8 that controls the tilt angle of the swash plate 3 of the hydraulic pump 2, a first solenoid valve 11 that operates the variable cylinder 8, and a brake 15 that brakes the hydraulic motor 4. , A brake cylinder 16 that operates the brake 15, a second solenoid valve 19 that operates the brake cylinder 16, a brake switch that is turned on and off by a brake pedal, and a brake switch that is turned on,
When turned off, the electric motor 6, the first and second solenoid valves 11, 1
It is composed of a plurality of relay switches for controlling the energization of the solenoids 14 and 21 of 9 and turning on the brake switch 25 ensures low engine speed, zero tilt angle of the swash plate 3, and braking by the brake 15 to ensure the vehicle. You can stop.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control device for a hydraulically driven vehicle that travels by driving a hydraulic motor with hydraulic oil discharged from a hydraulic pump driven by an engine.

[0002]

[Prior Art]

 As a control device for hydraulically driven vehicles, a running lever that increases or decreases the discharge amount of the hydraulic pump, a lever that controls the engine speed, a brake pedal that brakes the brake, etc. are provided to start, run, stop, adjust the running speed, and brake. The device is known.

[0003]

[Problems to be solved by the device]

 With such a control device, the travel lever, the lever, and the brake pedal operate independently, so that when the travel lever is set to the neutral position, the hydraulic pump discharge amount becomes zero, but the brake does not operate. Not only does the car start running without lowering the engine speed, but when the travel lever is set to the travel position and the hydraulic pump discharge is increased, the car suddenly starts.

Therefore, an object of the present invention is to provide a control device for a hydraulically driven vehicle that can solve the above-mentioned problems.

[0005]

[Means for Solving the Problems]

 A means for controlling the number of revolutions of the engine, a means for controlling the swash plate tilt angle of the hydraulic pump, a means for controlling the brake of the hydraulic motor, a brake switch that is turned on and off by a brake pedal, and a brake switch for this brake switch. A control device for a hydraulically driven vehicle comprising means for controlling each of the above means by turning it on and off.

[0006]

[Work]

 By depressing the brake pedal and turning on the brake switch, the engine speed can be reduced, the swash plate tilt angle can be zero, and the brake can be braked to stop the vehicle reliably.

[0007]

【Example】

 As shown in FIG. 1, the hydraulic pump 2 driven by the engine 1 changes the tilt angle of the swash plate 3 to increase or decrease the discharge amount per rotation, and the discharge pressure oil is supplied to the hydraulic motor 4. Then, the drive wheels 5 are driven by the hydraulic motor 4 to drive the vehicle, thereby forming a hydraulically driven vehicle. The engine 1 is controlled by the engine governor 7 controlled by the electric motor 6 to increase or decrease the rotational speed, The swash plate 2 of No. 2 is tilted by the variable cylinder 8, and the variable cylinder 8 is biased by the spring 9 in the direction to make the tilt angle zero, and when extended by the pressure oil in the extension chamber 10, the tilt angle becomes large. The expansion chamber 10 is supplied with the pressure oil discharged from the fixed pump 12 by the first solenoid valve 11, and the first solenoid valve 11 is held at the pressure oil supply position A by the spring 13 and When excited from 14, drain position B It made. The output shaft of the hydraulic motor 4 is provided with a brake 15. The brake 15 is braked / released by a brake cylinder 16, and the brake cylinder 16 is held in a braking direction by a spring 17 and released by pressure oil in a pressure receiving chamber 18. When the pressure oil supply position C and the solenoid 21 are excited by the spring 20, the second solenoid valve 19 is energized by the second solenoid valve 19 which supplies pressure oil to the pressure receiving chamber 18 by the second solenoid valve 19. The drain position is D. As shown in FIG. 2, the solenoid 14 of the first solenoid valve 11 is connected to the power source by the normally open contact 22a of the first relay switch 22, and the coil 22c of the solenoid 22 is a brake provided on the parking switch 23 and the brake pedal 24. The switch 25 connects to the power source and also connects to the coil 26c of the second relay switch 26. The normally closed contact 26b of the second relay switch 26 connects and disconnects the starter switch 27 and the contact piece 28d of the third relay switch 28, and the normally open contact 28a of the third relay switch 28 serves as the solenoid 21 of the second solenoid valve 19. , And its coil 28c is connected to the parking switch 23. The electric motor 6 is connected to a power source by an accelerator controller 29 so that it can be stopped, switched to a low speed state or a high speed state, and connected to a parking switch 23 and a brake switch 25 so that they are switched to a low speed state. is there.

Next, the operation will be described. When the brake pedal 24 is stepped on, the brake switch 25 is turned on, the coils 22c and 28c of the first and third relay switches 22 and 28 are energized, and the normally open contacts 22a and 28a are turned on, and the first and second solenoid valves are turned on. The solenoids 14 and 21 of 11 and 19 are energized. As a result, the first and second solenoid valves 11 and 19 are set to the drain positions B and D, so that the swash plate 3 in the variable cylinder 8 has a zero tilt angle and the brake cylinder 16 controls the brake 15. At the same time, the electric motor 6 shifts to a low speed state and the engine governor 7 shifts the engine 1 to a low speed state. In this way, when the brake pedal 24 is depressed, the engine speed is low, the discharge amount of the hydraulic pump 2 is zero, and the brake 15 is braked, so that the vehicle stops without making a sprint. When the brake pedal 24 is released from the above state, the brake switch 25 is turned off, the coils 22c, 28c of the first and third relay switches 22, 28 are not energized, and the normally open contacts 22a, 28a are turned off. When the first and second solenoid valves 11 and 19 are set to the pressure oil supply positions A and C, the variable cylinder 8 causes a large tilt angle of the swash plate 3 and the brake 15 releases so that the accelerator controller 29 starts the engine. Will be faster.

[0009]

[Effect of the device]

 By depressing the brake pedal 24, the engine speed is low, the discharge amount of the hydraulic pump 2 is zero, and the brake 15 is braked. Therefore, the brake pedal 24 can be stopped without running and the brake pedal 24 can be released. For example, the engine speed is high, the hydraulic pump 2 has a large discharge amount, and the brake 15 is released, so that the vehicle can start smoothly.

[Brief description of drawings]

FIG. 1 is a diagrammatic view of a hydraulically driven vehicle.

FIG. 2 is a control circuit diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Hydraulic pump, 3 ... Swash plate, 4 ... Hydraulic motor, 5 ... Drive wheel, 6 ... Electric motor, 7 ... Engine governor, 8 ... Variable cylinder, 11 ... First solenoid valve, 15 ... Brake, 16 ... Brake cylinder, 19 ... Second solenoid valve, 2
4 ... Brake pedal, 25 ... Brake switch.

Claims (1)

[Scope of utility model registration request] 1. A hydraulically driven vehicle that supplies hydraulic oil discharged from a hydraulic pump 2 driven by an engine 1 to a hydraulic motor 4 to drive driving wheels 5 to travel, and means for controlling the rotational speed of the engine 1. A means for increasing / decreasing the discharge amount of the hydraulic pump 2, a brake 15 for braking the output side of the hydraulic motor 4, a means for braking / releasing the brake 15, a brake pedal 24, and a brake pedal 24. By operating each of the above means by operation, the engine speed is low, the discharge amount of the hydraulic pump 2 is zero,
A control device for a hydraulically driven vehicle comprising means for braking the brake 15.