JPH08205608A - Work vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the oil temperature in the transmission case from rising due to the oil returned from the actuator. [Arrangement] An oil passage for supplying the oil stored in the transmission case 21 to an actuator and an oil passage for returning the oil from this actuator to a tank 28 are provided. By providing a suction pipe 30 that communicates with a lower space of the tank, and a blazer pipe 32 that communicates the upper position of the suction pipe 30 with the upper space in the tank, so that the oil level in the tank is 32A.
Negative pressure in the transmission case only when it rises more, or
Oil in the tank is sucked into the suction pipe 30 by the air pressure in the tank,
It is returned to the transmission case 21 via the pipe 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a work vehicle provided with a hydraulic system for supplying stored oil in a transmission case for transmitting power to a traveling device to a hydraulic actuator.

[0002]

2. Description of the Related Art Conventionally, an agricultural tractor can be taken as an example of the work vehicle constructed as described above. In this type of agricultural tractor, the stored oil in the transmission case is lubricated for the gear transmission in the transmission case. In addition to the above, it is also supplied to an actuator such as a hydraulic cylinder that raises and lowers a working device such as a tiller.

[0003]

In the case where the oil stored in the transmission case is used both as the lubricating oil and the hydraulic oil, the oil temperature easily rises, and the amount of oil that can be used also increases for the purpose of suppressing the increase in the oil temperature. Is desired. Also, in order to increase the amount of oil, it is possible to expand the volume of the transmission case, but it is necessary to basically modify the transmission case, and it is also possible to use an auxiliary tank to easily increase the amount of oil. Has been.

However, when an auxiliary tank is used, if the auxiliary tank and the transmission case are simply connected by a pipe or the like, the stored oil in the transmission case may flow to the auxiliary tank side when the vehicle body is tilted. In such a case, not only the amount of oil with respect to the transmission gear in the transmission case decreases, the lubrication performance deteriorates, but also the weight balance of the vehicle body may be lost.

An object of the present invention is to reasonably construct a work vehicle capable of suppressing an increase in oil temperature by increasing the amount of oil without basically modifying the transmission case.

[0006]

The features of the present invention are, as described at the beginning, in a working vehicle provided with a hydraulic system for supplying stored oil in a transmission case for transmitting power to a traveling device to a hydraulic actuator. A tank for returning the oil from the tank is provided separately from the transmission case, and a suction pipe that protrudes downward from the upper surface of the tank and communicates with a lower space in the tank, and the suction pipe and the transmission case are provided. The transmission case is provided with a pipe line for communicating with each other, and a breather pipe for communicating the suction pipe with an upper space in the tank is provided at an upper position of the suction pipe, so that the transmission case can be performed only when the oil level in the tank rises above the opening of the breather pipe. The oil in the tank is supplied to the transmission case through the suction pipe and the pipe by the negative pressure in the inside or the air pressure in the tank, and the action and effect are as follows.

[0007]

According to the above feature, the oil stored in the transmission case is supplied to the actuator when the hydraulic actuator is driven, and the oil whose temperature has risen by the actuator is returned to the tank. The low temperature oil is returned to the transmission case to suppress the rise in oil temperature in the transmission case, and when returning the oil in the tank to the transmission case, only when the oil level rises above the opening of the breather pipe,
The oil level in the transmission case decreases and the inside of the transmission case becomes negative pressure, or the internal pressure of the tank rises due to the rise of the oil level in the tank, and the oil in the lower space of the tank sucks in. The oil is returned to the inside of the transmission case through the pipe and the pipe, and the oil does not flow between the transmission case and the tank due to the inclination of the vehicle body, or an excessive amount of oil is not returned to the transmission case.

That is, in the present invention, by providing a tank separately from the transmission case, it is possible to increase the amount of oil that can be used in the entire work vehicle, and at the same time, after the oil returned from the actuator is radiated and cooled in the tank. It is possible to return the coldest oil to the transmission case, and at the time of this return, a special device such as a pump is required because it is sent to the transmission case based on the decrease of the oil in the tank and the increase of the oil in the tank. Without doing so, the amount of oil in the transmission case can be appropriately maintained.

[0009]

Therefore, by adding the tank, the amount of oil can be increased without basically modifying the transmission case, and the oil temperature in the transmission case can be maintained without causing an excess or deficiency in the amount of oil in the transmission case. The work vehicle that can suppress the rise of the vehicle was reasonably constructed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a steering handle 4 is provided at a front portion of a traveling machine body 3 including a drive-type front wheel 1 configured to be steerable and a drive-type rear wheel 2 configured to be steerable. And a driver's seat 5 are arranged, an engine 6 is arranged in the center of the traveling machine body 3, a hopper 7 for collecting the cut grass is mounted on the rear portion of the traveling machine body 3, and between the front and rear wheels. The scraping unit A is provided so as to be able to drive up and down, and the sweeper as a working vehicle is configured so that the cut grass scraped up by the scraping unit A is guided to the suction blower 9 through the duct 8 and put into the hopper 7 to be collected. To do.

As shown in FIGS. 1 to 3, the scraping unit A is a housing 10 formed in a horizontally long kamaboko shape.
The rotating brush 11 as a rotating body for scraping up the object to be collected on the ground is horizontally supported with respect to the internal position of
A hydraulic motor M1 that rotationally drives the rotary brush 11 is arranged on one lateral side of the housing 10, and a grounding wheel 12 is provided on the rear side of the housing 10. The housing 10 is connected in a suspended state to the lower end of a parallel quadruple type link mechanism 13 whose upper end is supported by the traveling machine body 3, and an elevating cylinder 14 as an elevating means for driving the link mechanism 13 to bend and extend. It is configured so that it can be moved up and down without changing the overall posture by driving.

The rotary brush 11 is a hydraulic motor M1.
A large number of discs 11B externally fitted and fixed to a shaft 11A driven by
The brush 11D is attached to the mounting rubber 11C supported in a posture in which the longitudinal direction is along the axis of rotation with respect to the outer peripheral edge.

The duct 8 is arranged in the front part of the housing 10, and a collecting cylinder portion 8A for collecting the cut grass scraped forward and upward by the rotating brush 11 is provided in a suction cylinder 9A extending downward from the suction blower 9. On the other hand, it is fitted in such a way that it can move relative to the vertical direction while allowing some tilting.

The hopper 7 is provided with a lid 7A that can be opened and closed on the rear surface side, and is supported by the traveling machine body via a parallel four-link type lift link 15, and an operation of a lift cylinder 16 that drives the lift link 15 to extend and retract. Can be moved up and down without changing the posture, and by driving the dump cylinder 17, the whole hopper can be switched between the dump posture and the horizontal posture around the lateral axis X, and the opening / closing cylinder 18 can be operated to rotate around the spindle 19. It is configured so that the lid 7A can be opened and closed.

As shown in FIG. 5, a hydraulic system of this sweeper is formed, and this system has a variable displacement hydraulic pump P1 driven by the power of the engine 6, and the hydraulic oil from this hydraulic pump is supplied. An oil passage that supplies the hydraulic motor M2 for traveling is formed. Further, a speed change pedal 20 for adjusting the discharge amount of hydraulic oil from the hydraulic pump P1 is arranged on the upper surface of the step of the boarding operation section, and the power from the hydraulic motor M2 is transmitted via the transmission case 21 to the rear wheel 2. And a transmission system for transmitting the transmission case 21 and the intermediate case 22 to the front wheels 1 via the respective transmission systems.

A main clutch 24 is mounted on a drive shaft 23 which penetrates the variable displacement hydraulic pump P1, and the power on the lower transmission side of the main clutch 24 is transmitted to a suction blower 9 via a belt transmission mechanism 25. An oil passage for forming a transmission system for transmitting to the hydraulic pump P2, and for sending hydraulic oil from the hydraulic pump P2 to the hydraulic motor M1 of the scraping unit A via the electromagnetically controlled first control valve V1. Has been formed.

Further, a constant displacement type hydraulic pump P3 driven by the engine 6 is provided, and hydraulic fluid from the hydraulic pump P3 is operated for steering front wheels through a second electromagnetically controlled control valve V2. To the steering cylinder 26, and to the steering cylinder 27 for steering the rear wheels via the electromagnetically controlled third control valve V3, and the lifting and lowering of the scraping unit A via the electromagnetically controlled fourth control valve V4. An oil passage for sending to the cylinder 14 is formed,
Further, the hydraulic oil sent out when the fourth control valve V4 is in the neutral position is sent to the lift cylinder 16 via the fifth control valve V5 and the dump cylinder 1 via the sixth control valve V6.
7, and an oil passage for sending to the open / close cylinder 18 via the seventh control valve V7 is formed.

In addition to the transmission case 21, this hydraulic system has a tank 28 for storing hydraulic oil, and a charge pump for the traveling oil passage system formed by the hydraulic pump P1 and the hydraulic motor M2. P4, a hydraulic motor M1 for driving the suction blower 9, and a transmission case 2 for the hydraulic pump P3 for driving the actuator.
The oil passage for supplying the stored oil of No. 1 and returning to the tank 28 the return oil from the actuators other than the front and rear steering cylinders 26 and 27, and the oil sent out when the plurality of relief valves are operated (the direction of the arrow in the figure). Oil is returned to).

As shown in FIG. 1, by arranging the tank 28 at the center position of the vehicle body 3 in the front-rear direction, the fluctuation of the oil level due to the inclination of the machine body 3 is reduced, and as shown in FIG. 28 is formed in a hermetically sealed state, has a flange 29 for forming a return oil passage on the upper surface, and has a pipe-shaped suction pipe 30 which projects downward from the upper surface and communicates with a lower space in the tank. The tank and the transmission case 21 communicate with each other via a conduit 31 that communicates with the pipe 30. Further, a breather pipe 32 is provided at an upper position of the suction pipe 30 to connect the suction pipe 30 and an upper space of the tank 28.

From this fact, the transmission case 21 is used during work.
The stored oil in the lift cylinder 14, lift cylinder 16,
Oil that is supplied to the actuator such as the dump cylinder 17 and whose temperature has risen by the actuator is stored in the tank 28.
In addition, when the oil in the tank is returned to the transmission case 21, only when the oil level rises above the opening 32A of the blazer pipe 32, the oil level in the transmission case 21 decreases and the inside of the transmission case becomes negative pressure. Or the internal pressure of the tank 28 rises due to the rise of the oil level in the tank 28, whereby the oil in the lower space in the tank 28 is sucked into the suction pipe 30,
The oil of a relatively low temperature in the lower space of the tank 28 is returned to the transmission case 21 at the time of this return, thereby suppressing an increase in the oil temperature in the transmission case 21. Has become. By forming such an oil passage system, oil does not flow between the transmission case 21 and the tank 28 due to the inclination of the vehicle body 3, or an excessive amount of oil is not returned to the transmission case 21. .

[Other Embodiments] In addition to the above embodiments, the present invention is
For example, it is applicable to a working device including a backhoe and a dozer device.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

[Figure 1] Overall side view of the sweeper

FIG. 2 is a side view of the scraping unit.

FIG. 3 is a rear view of a vertical section of the scraping unit.

FIG. 4 is a vertical sectional side view of the tank.

[Fig. 5] Hydraulic circuit diagram

[Explanation of symbols]

 21 Transmission Case 28 Tank 30 Suction Pipe 31 Pipeline 32 Breather Pipe 32A Opening

Claims (1)

[Claims] 1. A transmission case (2) for transmitting power to a traveling device.
A working vehicle including a hydraulic system for supplying the stored oil of 1) to a hydraulic actuator, the tank (28) in which oil from the hydraulic system is returned is provided separately from the transmission case (21). A suction pipe (30) which protrudes downward from the upper surface of the tank (28) and communicates with a lower space in the tank, and the suction pipe (30)
A pipe line (31) for connecting the transmission case (21) and the transmission case (21).
Is provided at the upper position of the suction pipe (30).
0) and the upper space in the tank are communicated with each other, the negative pressure in the transmission case is generated only when the oil level in the tank rises above the opening (32A) of the breather pipe (32), or A work vehicle for supplying oil in the tank to the transmission case (21) through the suction pipe (30) and the pipe line (31) by the air pressure in the tank.