WO2001064575A1

WO2001064575A1 - Hydraulic-driven working vehicle

Info

Publication number: WO2001064575A1
Application number: PCT/JP2000/002946
Authority: WO
Inventors: Yoshiyuki Enmeiji
Original assignee: Tcm Corporation
Priority date: 2000-02-25
Filing date: 2000-05-08
Publication date: 2001-09-07
Also published as: JP2001233593A

Abstract

A hydraulic-driven working vehicle, wherein a pressure oil is fed from a hydraulic pump (30) to both hydraulic motors (21A, 21B) through piping to perform forward and backward runnings and the rotating directions of the hydraulic motors are changed to switch a running mode between a forward running and a reverse running, the speed of an engine (25) and a hydraulic pressure (oil flow rate) from the hydraulic pumps are controlled to vary the speeds of the hydraulic motors in order to control the speed of the vehicle and, when the vehicle performs a stationary turning (Z) by a turning (pivot turn), either of valve means (37A, 37B) is switched to the state of ON, whereby the pressure oil can be fed from the hydraulic pump to the other port of the right and left hydraulic motors so as to rotate the right and left hydraulic motors in the directions reverse to each other in order to perform a stationary turning, and the reverse rotation of the right and left front wheels (3A, 3B) for the stationary turning can be performed by one hydraulic pump only so that it is advantageous in cost and mountability.

Description

Specification

Hydraulically driven work vehicle Technical field

The present invention relates to an engine-type work vehicle employing a hydraulic drive system. Background art

Conventionally, as a power transmission device for a general engine-type forklift, a clutch type or a torque converter type is the mainstream power ³ ', and in addition, an engine-type forklift that employs a hydraulic drive system There are also feet. Forklifts employing this hydraulic drive system are provided, for example, in the configurations shown in Figs.

That is, the forklift 1 is provided with a pair of left and right front wheels (drive wheels) 3A and 3B at the front of the vehicle body 2 and a pair of left and right rear wheels 4A and 4B at the rear. A driver's seat 5 is provided in front of the vehicle body 2 and above. A vertically extensible mast 6 is attached to the front end of the vehicle body 2 so as to be rotatable in the front-rear direction via a connecting shaft 7 in the vehicle width direction, and is a tilt cylinder that rotates back and forth. One eight is provided between the vehicle body 2 and the mast 6.

The mast 6 includes a pair of left and right outer frames 9 on the forklift 1 side, and a pair of left and right inner frames 10 guided by the outer frame 9 and capable of ascending and descending. A lift cylinder 11 is provided between the inner frame 10 and the inner frame 10. Also, a lift bracket 12 is provided, which is guided to the inner frame 10 side and can be moved up and down. The lift bracket 12 has a pair of upper and lower fingers. A pair of left and right forks 13 are provided via a cover.

The driver's seat 5 is provided with a seat 15 and a handle 16 positioned in front of the seat 15. Above the front pipe, a front pipe standing from the main body 2 side is provided. A head guide 19 is provided via a 17-pin pipe 18. Further, a power pin 20 is provided on the main body 2 behind the seat 15.

The rims 3a and 3b of the pair of left and right front wheels 3A and 3B are connected to the rotary flanges (drive shafts) 22A and 22B of hydraulic motors 21A and 21B, respectively. It can be mounted directly via the brackets 23A and 23B, and is linked to the hydraulic motors 21A and 21B. The mounts of the hydraulic motors 21A and 2IB are fixed to the vehicle body 2, ie, to the front frame.

An engine 25 is provided on the vehicle body 2 side, and a pair (a plurality) of hydraulic pumps (HST tandem pumps) 40A and 40B are directly attached to the engine 25. At that time, the mounting method is rubber mounting with the engine 25 and the frame. Then, one hydraulic pump 40A, 40B corresponds to one hydraulic motor 21A, 21B, that is, a two-pump two-motor hydraulic drive system. (HST system), the corresponding hydraulic pumps 4OA and 40B and the hydraulic motors 21A and 21B are connected via piping (hydraulic hoses) 41A and 41B, respectively. Connected.

A pair of left and right rear wheels 4A, 4B are provided to be able to turn around the longitudinal axes 14A, 14B with respect to the vehicle body 2, respectively. 26 indicates a change lever and 27 indicates an accelerator pedal.

In such a conventional configuration, the left and right The front wheels 3A, 3B and the left and right rear wheels 4A, 4B are oriented in the front-rear direction. The forward / backward traveling is performed by the change lever 26. The forward / backward traveling signal is input to the controller, and the traveling direction of the hydraulic pumps 40A and 40B is directed by the traveling command through the controller. And change the rotation direction of the hydraulic pressure motor 21A and 21B.

Further, by inputting the vehicle speed command signal to the controller with the accelerator pedal 27, the rotation speed of the engine 25 and the flow rate of oil pressure (oil flow rate) from the hydraulic pumps 4OA and 40B are controlled. As a result, the speed control is performed by changing the rotation speed of the hydraulic motors 21A and 2IB.

Then, in-place turning can be performed with the central portion between the front wheels 3A and 3B as a fulcrum by controlling the rotation direction of one of the hydraulic pumps 40A and 40B to be reversed. In this way, when turning in place using the hydraulic drive system, the left and right front wheels 3A and 3B are reversed, so the left and right hydraulic motors 21A and 21B are controlled separately. There is a need to. For this purpose, two hydraulic pumps 40A and 40B are used, and the flow rate and direction are controlled independently.

However, in the conventional configuration described above, since the two pumps and two motors are used, that is, since two hydraulic pumps 40A and 40B are used, cost and mountability are improved. Disadvantaged in terms of Disclosure of the invention

Therefore, an object of the present invention is to provide a hydraulically driven working vehicle that enables a hydraulically driven system having an in-situ turning function with one pump and two motors.

In order to achieve the above-mentioned object, a hydraulically driven work vehicle according to the present invention is provided. A pair of left and right front wheels and a pair of left and right rear wheels are provided on the vehicle body.Each front wheel is linked to a drive shaft on the hydraulic motor mounted on the vehicle body, and an engine is mounted on the vehicle body side. A single hydraulic pump to be driven is provided, and valve means are interposed in the piping from the hydraulic pump to both hydraulic motors, and each rear wheel is arranged around the vertical axis with respect to the vehicle body side. It is characterized by being provided to be able to turn freely.

According to the configuration of the present invention described above, the right and left front wheels and the left and right rear wheels are oriented in the front-rear direction during normal straight running, and both valve means are in the off state. And when traveling forward and backward, pressurized oil from the hydraulic pump

This can be done by supplying to both hydraulic motors via pipes. At that time, the direction of oil flow of the hydraulic pump is switched, and the rotation direction of the hydraulic motors is changed, so that the vehicle travels forward or reverse. Furthermore, by controlling the engine speed and the hydraulic pressure (oil flow rate) from the hydraulic pump, the speed of the hydraulic motor can be changed to control the speed.

In addition, turning control is performed by operating a handle or the like, and can be performed with hydraulic pressure to provide a function. Then, when performing an on-the-spot turn from a turn (pivot turn), one of the valve means is switched to an ON state. Thus, the hydraulic oil from the hydraulic pump is supplied to the other ports in the left and right hydraulic motors, and the left and right hydraulic motors are rotated in opposite directions, thereby making a turn in place.

As described above, according to the present invention, in-situ turning can be performed by interposing valve means between one hydraulic pump and two hydraulic motors and switching these valve means. In other words, the right and left front wheels can be reversed using a single hydraulic pump to make a turn on the spot. It can be provided as an advantage in terms of cost and mountability. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an embodiment of the present invention and is a side view of a hydraulically driven work vehicle.

FIG. 2 is a partially cutaway plan view of the hydraulically driven work vehicle when both valve means are off.

FIG. 3 is a partially cutaway plan view of the hydraulically driven work vehicle when one-side valve means is on.

FIG. 4 is a schematic plan view illustrating the operating state of the hydraulically driven work vehicle.

FIG. 5 shows a conventional example, and is a side view of a hydraulically driven work vehicle. FIG. 6 is a partially cutaway plan view of the hydraulically driven work vehicle. BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components or almost the same components as those of the above-described conventional example (FIGS. 5 and 6) are denoted by the same reference numerals, and the details are omitted.

That is, in FIGS. 1 and 2, 1 is a forklift, which is an example of a working vehicle, 2 is a vehicle body, 3A and 3B are front wheels (drive wheels), 3a and 3b are rims, 4 A and 4 B are rear wheels, 5 is a driver's seat, 6 is a mast, 7 is a connecting shaft, 8 is a tilire cylinder, 9 is an outer frame, 10 is an inner frame, and 11 is a lift shaft. Leader, 12 is lift bracket, 13 is fork, 14 A , 14B is the vertical axis, 15 is the seat, 16 is the handle, 17 is the front eve, 18 is Ryape, 19 is the guard, and 20 is the county night , 21 A and 2 IB are hydraulic motors, 22 A and 22 B are rotating flanges (drive shafts), 23 A and 23 B are coupling tools, 25 is an engine, and 26 is a change lever. , 27 indicate an accelerator pedal, respectively. One hydraulic pump (HST tandem pump) 30 is directly attached to the engine 25. In order for one hydraulic pump 30 to correspond to two hydraulic motors 21 A and 2 IB, that is, a hydraulic drive system (HST system) of one pump and two motors and one type is used. The main pipes 33 and 34 from both ports 31 and 32 in the hydraulic pump 30 are connected to branch pipes (such as hydraulic hoses) 33 A, 33 B, 34 A and 34, respectively. Β are connected to both ports 35 Α, 35 Β, 36 A, 36 B in the hydraulic motors 21 A, 21 Β through Β.

Solenoid valves (valve means) 37 A, 37 B are interposed in the left and right branch pipes 33 A, 34 A, 33 B, 34 B, respectively. Electric signals to the solenoid valves 37A and 37B are output from a steering angle sensor (not shown) attached to the handle 16 and the rear axle.

The operation of the above embodiment will be described below.

(A) in Fig. 1, Fig. 2 and Fig. 4 show normal forward and backward traveling. At this time, the left and right front wheels 3A and 3B and the left and right rear wheels 4A and 4B are oriented in the front-rear direction, and the solenoid valves 37A and 37B are off. Forward and backward traveling is performed with the change lever 26, and forward and backward signals are input to the controller. This can be done by changing the direction of oil flow of the hydraulic pump 30 by changing the direction of rotation of the hydraulic motors 21A and 21B in response to all the travel commands.

In other words, the pressurized oil from port 31 is supplied to ports 35A and 35B via main pipe 33 and branch pipes 33A and 33B, whereby the pressure oil shown in Figs. As shown in (A), the vehicle travels forward, and pressurized oil from the port 32 is supplied through the main pipe 34 and the branch pipes 34A and 34B to the ports 36A and 34B. By supplying to 36 B, it will be at the time of reverse driving.

Further, by inputting a vehicle speed command signal to the controller with an accelerator pedal 27, the number of revolutions of the engine 25 and the hydraulic pressure (oil flow rate) from the hydraulic pump 30 are controlled. Speed control is performed by changing the number of rotations 21A and 21B of 1A and 21B.

The turning control is performed by a worker sitting in the seat 15 of the driver's seat 5 operating the handle 16 or the like, and at that time, the running speed is changed by changing the angle of the handle 16 By controlling the swash plate of the hydraulic pump 30 according to the position signal (rotation angle), the rotation speed and the rotation direction of the hydraulic motors 21A and 21B can be controlled. That is, it can be performed by controlling the number of rotations and the direction of rotation of both hydraulic motors 21A and 21B in accordance with the turning angle of the node drill 16 as follows.

a: When the handle 16 is neutral, as shown in Fig. 4 (A), the rotational speeds 21a and 2lb of the left and right hydraulic motors 21A and 2IB are the same. And go straight X.

b: When the cutting angle of the nozzle is small As shown in Fig. 4 (B), there is a difference between the left and right rotation speeds 2 la and 2 lb by the left and right rotation in the same direction (for example, 2 la> 2 lb), so that right outside Y can be performed with the fulcrum 0 outside the main body 2. c: When the steering angle is at the middle position As shown in Fig. 4 (C), rotate only one front wheel. For example, only the left front wheel 3A is rotated 2 la, whereby a right turn Y (pivot turn) can be performed with the fulcrum 〇 near the right front wheel 3B. In this case, by providing a differential function by hydraulic pressure, a rotation difference is given to the left and right hydraulic motors 21A and 21B.

In the above cases a to c, both solenoid valves 37A and 37B are in the off state as shown in FIG. 2, and the hydraulic oil from port 31 is supplied to hydraulic motor 21A. , 2IB and flow to ports 35A and 35B, and the front wheels 3A and 3B rotate in the same direction. When turning, the pump is driven by a general one-pump, two-motor type that has a differential function by hydraulic pressure.

Then, when making an in-situ turn from right turn Y (pivot evening), one of the solenoid valves 37 A and 37 B is turned on by a signal from the steering angle sensor. .

That is, as shown in FIG. 3, for example, by switching the solenoid valve 37B on the right side to the on state, the hydraulic oil from the port 31 is supplied to the main pipe 33, the branch pipe 33B, and the solenoid pipe. Can be supplied to the port 36B via the valve 37B and the branch pipe 34B. As a result, the right hydraulic motor 21B is rotated in the reverse direction, and the left solenoid valve 37A is off, so that the pressure oil from the port 31 is supplied to the main piping 3 3. Branch pipe 33A, can be supplied to port 35A via solenoid valve 37A, so that the left hydraulic motor 21A can rotate forward and turn in place. .

Then, as shown below, the difference between the rotational speeds of the two hydraulic motors 21 A and 21 B between the left and right turns (one pivot) and the spot turn Is performed by the differential function using hydraulic pressure.

d: When the handle angle is larger than the middle angle As shown in Fig. 4 (D), the left and right rotation speeds 21a and 21b have a difference in the left and right rotation (for example, , 21 a> 2 lb), so that a right turn Y close to a turn can be performed with the fulcrum 0 between the front wheels 3 A and 3 B.

e: When the handle angle is the maximum (handle lock), as shown in (E) in Fig. 4, the left and right rotation speeds 2la and 2lb are the same in left and right opposite directions. In this case, the center point between the front wheels 3A and 3B is used as a fulcrum ◦ to enable in-situ turning Z with a minimal turning radius.

In the above, (B) in Fig. 4 to (E) in Fig. 4 show the case of right turn Y and right turn turn Z, but by reversing the cutting direction of the handle 16 A left turn and an in-place left turn are performed in the same manner. Also, the case of forward travel is shown, but the same applies to reverse travel. During left and right turns and on-the-spot turns, the left and right rear wheels 4 A and 4 B in the form of a turning cascade follow around the longitudinal axes 14 A and 14 B.

The forklift 1 is driven by a hydraulic drive system (HST system) with one pump and two motors, and the left and right front wheels 3A and 3B, which are drive wheels, are connected to a solenoid. By controlling the valves 37 A and 37 B separately by switching, the maneuverability can be improved, the turning radius can be reduced, and it is advantageous in terms of cost and mountability.

The front wheels 3 A and 3 B are mounted on the hydraulic motors 21 A and 21 B, respectively, which are mounted on the vehicle body 2. The force transmission section can be simplified, and the degree of freedom in layout can be increased. Furthermore, in addition to the high efficiency that is characteristic of the hydraulic drive system and the front differential is not required, low fuel consumption can be expected by optimal control of the engine.

Such a fork lift 1 is lifted by an operator sitting in the seat 15 of the driver's seat 5 by, for example, operating a lift lever and operating the lift cylinder 11. The fork 13 can be moved up and down along the mast 6 via the bracket 12 and the like, so that the intended fork work can be performed. By operating the tilt reno 1 to operate the tilt cylinder 18, the mast 6 can be turned (tilted) around the connection shaft 7, and thus the lift bracket 12, etc. The attitude of the fork 13 can be changed via the.

In the above-described embodiment, the forklift 1 is shown as a work vehicle, but this can be similarly applied to other transport vehicles and the like.

In the above-described embodiment, the solenoid valves 37A and 37B are shown as the valve means, but may be valves that can be switched by a lever.

Claims

The scope of the claims

1. A hydraulically driven work vehicle with a pair of left and right front wheels and a pair of left and right rear wheels mounted on the vehicle body. Each front wheel is connected to the drive shaft of the hydraulic motor mounted on the vehicle body. A single hydraulic pump driven by the engine is provided on the vehicle body side, and valve means are interposed in the piping from this hydraulic pump to both hydraulic motors, respectively. It is characterized by being provided so as to be pivotable around the vertical axis center with respect to the side.