JPS59216733A - Working vehicle - Google Patents

Abstract

PURPOSE:To make it possible to easily return a hydraulic drive vehicle to its neutral and resting condition, by short-circuiting a passage in a hydraulic speed change unit in association with a pedal type speed change unit in the vehicle. CONSTITUTION:A short-circuit oil passage 21 having therein a selector valve 26 is provided in a hydraulic circuit 21 for supplying hydraulic pressure between a variable displacement type pump 18 coupled to an engine E and a hydraulic motor 20 coupled to wheels through a gear type speed change mechanism 7, in parallel with the hydraulic motor 20. The selector valve 26 is urged toward its open side by means of springs 27, 27, and is therefore set in its forward or backward moving position by depressing a foot pedal type speed change control member, overcoming the springs 27. When a foot is released from the pedal type speed change control member, the selector valve 26 is turned into its open position by means of the springs 27 to return to its neutral position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a main-pressure speed change system for controlling a flow formed by connecting a driving part and a traveling device in communication with a fluid pressure pump interlocking with the driving section and a fluid pressure motor interlocking with the traveling device. In the above-mentioned work unit, the vehicle is connected to a work vehicle that is interlocked with the vehicle through a device.In the above-mentioned work unit, it is possible to use a speed change operation device such as a foot pedal to provide stepless Vc support by holding the neutral position at both traveling speeds of t%gtl and backwards. At the same time, springs and springs were installed to return the gear shift operation to the neutral position when the gear shift operation tool was released. Another drawback was that a large biasing force could not be used as a projectile, and the speed change operating tool could not be maintained at the neutral position, causing the vehicle to travel unexpectedly.

In view of the above points, the present invention is based on the above-mentioned F! In order to achieve the purpose, in the work XI/LVc mentioned above, 1
11. A short-circuit flow path is connected to the pressure fluid supply flow path that communicates with the pump and the motor, and a switching valve is provided to open and close the short-circuit flow b\tVr-1, and n11 The switching valve is provided with a bullet for biasing it toward the opening side, and the l-speed operation tool of the hydraulic transmission and the switching valve are connected to each other. , and are interlocked and connected so that the speed can be freely changed while closing the Btt switching valve against the biasing force of the bullet. r, characterized.

In other words, as you release both gear shift operations to stop driving,
Due to the biasing force of the bullet, the control tool returns to the neutral position 11, and at the same time, the switching valve is operated to switch 9J, and the pressure oil from the pump is driven to the short-circuit flow W5, and the motor is Pressure fluid is not supplied and the vehicle stops running.

Therefore, if the speed control not only returns to its neutral position, but also opens the switching valve, travel is stopped, and the speed change operation resists the biasing force of the projectile and causes an unexpected VC displacement. In addition, as long as the switching valve P is in the open position, the motor will not be activated, and the vehicle will be able to maintain a perfectly stable running stop state, preventing unexpected running when the vehicle is temporarily stopped while the engine is still running. It is now possible to avoid this and improve safety.

Hereinafter, practical examples of the present invention will be explained in detail based on illustrative drawings.

The driving body is made up of a single wheel (11, +21) mounted on a curved hard dog, and the engine fails (11
M is installed and in the driver's seat J at the rear (3)? A compact lift arm (4) is provided at the rear for driving up and down various working devices such as a rotary tiller, and a power output 1f'-1IIF61 for transmission is provided, and a power r from the engine ill is provided. The power is transmitted to the morning power extraction shaft (5), and the tsfI rear wheels [11, 121 are hydraulic type gears and speed devices as an example of the fluid pressure type] and the gear type transmission mechanism (7).
) The VC4m is constructed so as to reach the floor through the work vehicle.

The hydraulic transmission (6) is housed in a sheet metal housing (91K) that also serves as the seven frames of the vehicle body, on the lower side between the seat (3) and the seat (8).

The operating system 11111 for the hydraulic transmission (6) consists of a downward Y-shaped swinging arm 1121 with a complete neutral position holding mechanism (11), and a pedal 0:
A swinging member (+5) integrally interlocked with 1 via a support shaft H
The tray and the rod are of course interlocked and connected, and the shock absorbing member α force is also interlocked to avoid sudden sudden gear changes due to depression of the pedal teal.

ntJ E 1111Ff:, Formula B Il, Transmission tel tri, Figure a [As shown, engine (F!
l Vc interlocking discharge capacity town variant hydraulic pump (I paddy and
The wheels (1) are connected to the interlocking hydraulic motor 12!01 via the 12+VC gear type transmission mechanism (7), and a one-way valve μs is connected to the communication oil passage ■11 for supplying pressure oil. 1
22H-The interposed charge oil passage t2al is connected to the jiggyjibonguv and 41 in series. The trunnion shaft (18 m) of the curved pump 1J81 and the swing arm 05) are connected to be rotatable together.

A short circuit oil path is connected to the pressure oil supply communication oil path I2 in parallel with the hydraulic motor pot, and a three-position switching valve TPFT is installed in the short circuit oil path to open and close it, and the standard (by opening the oil passage 4, the operation of motor 4 is stopped and running is stopped, and by closing the other short-circuit oil passage, motor C1jJ) 'ii-The VC is configured so that it operates and travels. Is that the switching valve 12 (2)? In order to bias the opening operation side, a pair of springs (l:l) as an example of a bullet is attached, and a switching valve (c) and a part of the lever O (13 m
) are connected through the hole (c), and by depressing the pedal U-mari, the switching valve (to) is switched to the closed position against the biasing force of the spring l:l force, +27).
As the foot is removed from pedal +131 while operating the high-speed side Vcf speed of either I or advance, pedal Q1 returns to the neutral position and the switching valve side is arbitrarily switched in a circle pattern to ensure that the vehicle stops traveling. It is configured as follows.

Pedal 0311' (instead, a manual operation lever may be provided, and these are used to perform gear shifting operations (generally referred to as 131).

The present invention is not limited to the above-mentioned tire type traveling device and truck type, but can also be applied to a companion type equipped with a crawler type traveling device, and can also be applied to not only tractors but also combine harvesters, transport vehicles, and earthmoving vehicles. Applicable to various work vehicles.

[Brief explanation of the drawing]

The drawings show a practical example of a working vehicle according to the present invention. Fig. 1 is an overall side view of the tractor, Fig. 2 is an enlarged side view with a portion of the main Hs omitted, and Fig. 8 is a hydraulic circuit diagram. (6)...Fluid pressure type fast remanufacturing, facing...
Quick operation tool, bet...Fluid pressure pump, four...
...Fluid pressure motor, 1211...Flow path, (c)
...Short circuit flow path, Hiroto...Switching valve, 輯)
......Ammunition, (El...115(#) part.

Claims (1)

[Claims] A hydraulic transmission device (6) that connects the driving unit and the traveling device in communication with a fluid pressure pump H that is linked to the driving unit and a fluid pressure motor 4 that is linked to the traveling device. It is an interlocking work vehicle, and a short-circuit flow path (C) is connected in communication with the pressure fluid supply flow path circle that connects the pump shaft and the motor 4 of No. 011, and the short-circuit flow path 121
19VC, provide an example of a switching valve to open and close it, and
A bullet ρη for biasing it toward the open side is attached to the male exchange valve, and a speed operating device of the fluid pressure type speed device (6) 011, the switching valve, and the bullet 127 are added. ) A working vehicle that is connected to the GJ so that the FJtI switching valve can be closed and the gears can be changed freely against the biasing force of the FJtI switching valve.