JPH06117401A - Operating fluid tank - Google Patents

Abstract

PURPOSE:To suppress variation in the level in a tank body to the possible minimum extant. CONSTITUTION:An oil restraining plate 20, obtained by forming a plate body of a specified width in a frame shape, is fixed to the interior wall surface of four peripheries of a tank body 11a by means of welding or the like in plural number of stages in suck a manner that the plate surface may be parallel to the fluid level. When the return oil flows into the tank body 11a through a return oil induction inlet 15, its flow is braked due to its contact with the oil restraining plate 20 whereby tropping of air is restrained to the minimum and agitation of operating fluid is also restrained to the minimum. Air bubbles floating in the operating fluid come in contact with the oil restraining plate 20, caught and removed. Furthermore, even if the operating oil tank 11 is tilted, the operating oil sticks to the oil restraining plate 20 because the operating oil has a certain degree of viscosity and if even the operating fluid tank 11 is oscillated or fluctuated from the tilted state, the oil level may not make any big swing or wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic oil tank provided in a machine provided with a hydraulic operating mechanism such as a hydraulic excavator and other construction machines.

[0002]

2. Description of the Related Art A construction machine is a typical machine equipped with a hydraulic actuating mechanism. As this construction machine, for example, a hydraulic excavator is designed to be driven and turned by a hydraulic motor. The boom, arms, buckets, etc. that compose the front working mechanism are operated by hydraulic cylinders. Then, in order to supply pressure oil to the hydraulic motor or hydraulic cylinder as an actuator,
Equipped with hydraulic pump and hydraulic oil tank. When the hydraulic pump is operated, the hydraulic oil in the hydraulic oil tank is sucked and pressurized, and this hydraulic oil is supplied to the actuator,
A hydraulic circuit is constructed in which the actuator operates and the return oil from the actuator is returned to the hydraulic oil tank.

Among the above-mentioned actuators, in the hydraulic cylinder, the volume inside the cylinder body changes only by the volume of the piston rod when the cylinder expands and contracts. There will be a difference in the amount of oil returned to the tank. Therefore, as the hydraulic oil tank, the one having the configuration shown in FIGS. 7 and 8 has been conventionally used.

The hydraulic oil tank 1 has a tank body 1a,
A suction pipe 2 for supplying hydraulic oil to the hydraulic pump is connected to the lower surface of the tank body 1a, and a return pipe 3 from the actuator is connected to the upper portion of the side wall. Therefore, the tank body 1a has a suction port 4 and a return oil introduction port 5 to which the suction pipe 2 and the return pipe 3 are respectively connected. Further, a filter 6 is attached to the suction port 4 so as to supply foreign matter and the like mixed in the hydraulic oil to the hydraulic pump in a removed state. Further, an atmosphere communication hole 7 is provided on the upper surface of the tank body 1a, and when the liquid level of the hydraulic oil in the tank body 1a changes, the outside air is sucked and discharged from the atmosphere communication hole 7.

By the way, if the hydraulic oil tank 1 vibrates,
When shaken, the liquid surface will sway or wavy,
In the extreme case, there is a possibility that the filter 6 attached to the suction port 4 may be exposed to the air. When hydraulic oil is sucked into the hydraulic pump in this state, cavitation occurs. Further, when the return oil flows from the return pipe 3 into the tank body 1a in a state where the liquid surface of the hydraulic oil is located below the return oil introduction port 5, when the return oil collides with the liquid surface, air is returned. The working oil in the tank body 1a is agitated as the oil is rolled up. When air is entrained in the hydraulic oil, air bubbles are mixed in, and the air bubbles are not effectively released into the atmosphere unless the hydraulic oil becomes stationary. However, each time the return oil enters the tank body 1a, the working oil is agitated, so that the working oil is not in a stationary state during continuous operation or the like, and the working oil still mixed with air may be supplied to the suction pipe 2. is there. Even in this case, cavitation still occurs.

In consideration of the above points, the partition plate 8 for partitioning the inside of the tank body 1a into two chambers is provided.
Therefore, the inside of the tank body 1a is divided into a hydraulic oil outflow chamber S having a suction port 4 and a hydraulic oil inflow chamber R having a return oil introduction port 5, and the partition plate 8 is operated. A hydraulic fluid communication portion 8a for communicating the hydraulic fluid inflow chamber R and the hydraulic fluid outflow chamber S, and an air communication portion 8b are provided.

As described above, when the tank body 1a is divided into two chambers, the ratio of the depth to the liquid surface area increases, so that the degree of fluctuation of the liquid surface due to shaking can be reduced, and the tank 2 can be attached to the suction port 2. The occurrence of the situation in which the existing filter 6 is exposed to the air can be suppressed to some extent, and even if some air is entrained when the return oil flows from the return oil introduction port 5 into the tank body 1a. Since it takes a certain amount of time for this hydraulic oil to transfer from the hydraulic oil inflow chamber R to the hydraulic oil outflow chamber S via the hydraulic oil communicating portion 8a of the partition plate 8, during this time, the bubbles rise and are discharged into the air. You can do it.

[0008]

Here, in the hydraulic excavator, the hydraulic oil tank 1 is installed on a revolving structure T as shown in FIGS. 9 and 10, and the revolving structure T is of a crawler type. It is possible to turn with respect to the traveling body C. The front working mechanism F is connected to the revolving structure T.

Now, the hydraulic excavator is working to excavate the earth and sand on the sloping ground, and as shown in FIG. 9, the front working mechanism F excavates the earth and sand at the lower position on the sloping ground to turn the revolving structure T. Then, as shown in FIG.
Suppose that the excavated earth and sand were discharged at a position above the slope.

In the state shown in FIG. 9, since the entire hydraulic excavator is tilted, the liquid level of the hydraulic oil tank 1 installed on the revolving structure T, after a certain amount of time, passes through the hydraulic oil communicating portion 8a. Since it moves from the hydraulic oil outflow chamber S side to the hydraulic oil inflow chamber R side through the state shown in the solid line in FIG. 11, the liquid level on the hydraulic oil outflow chamber S side decreases. In this state, the traveling body C travels and the front working mechanism F
Is operated or the revolving structure T is revolved, the hydraulic oil tank 1 vibrates or swings, and the liquid surface moves or undulates. As a result, the liquid level in the hydraulic oil outflow chamber S, which is originally in the lowered state, is further lowered, and the filter 6
There is a possibility that the suction port 4 equipped with is exposed to the air. In particular, when the hydraulic cylinder 13 for operating the front work mechanism is in the extended state, the amount of hydraulic oil in the hydraulic oil tank 1 decreases, so the liquid level further decreases, and relatively small vibrations and vibrations occur. Even if there is movement, there is a drawback that the filter 6 is immediately exposed to the air.

On the contrary, in the state of FIG. 10, the liquid surface of the hydraulic oil tank 1 is lowered as shown by the alternate long and short dash line in FIG. In this state, the filter 6 is less likely to be exposed to the air, but when the return oil flows from the return oil introduction port 5 into the tank body 1a, the return oil introduction port 5 and the liquid surface in the tank body 1a are separated from each other. There is also a problem that the difference becomes large, the amount of air entrained when the return oil flows in further increases, and the degree of stirring of the hydraulic oil also increases.

The present invention has been made in view of the above points, and an object of the present invention is to reduce the fluctuation of the liquid level in the tank body as much as possible.

[0013]

In order to achieve the above-mentioned object, the present invention has a constitution in which an oil control plate is fixedly provided on the inner surface of the side wall of the tank body to which the suction pipe and the return pipe are connected. That is the feature.

[0014]

With this structure, even if the hydraulic oil tank vibrates or shakes, the action of the oil control plate can prevent the hydraulic fluid level from wavy or moving. , There is no risk that the filter attached to the suction port will be exposed to the outside air. Further, when the return oil flows into the hydraulic oil tank, the return oil comes into contact with the oil control plate, so that air entrapment is suppressed and the hydraulic oil in the tank body is agitated. Can also be suppressed. Moreover, since the oil control plate faces the hydraulic oil, air bubbles floating in the liquid will quickly adhere to the oil control plate, and the hydraulic oil containing air bubbles will be supplied to the hydraulic pump from the suction port. There is no inconvenience.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, FIGS. 1 to 5 show a first embodiment of the present invention. In FIGS. 1 to 3, 11 is a hydraulic oil tank, and the hydraulic oil tank 11 is a tank main body 11
In a, a suction port 14 and a return oil introduction port 15 to which the suction pipe 12 and the return pipe 13 are respectively connected are formed, and a filter 16 is attached to the suction port 14 and further an atmosphere communication hole. 17 is the tank body 11
It is formed on the upper surface of a. The above points are the same as those of the conventional hydraulic oil tank described above. A partition plate is not provided on the tank body 11a.

An oil control plate 20 is fixedly mounted on the inner surface of the peripheral wall portion of the tank body 11a on the four sides. As shown in FIG. 4, the oil control plate 20 is formed by forming a plate body having a predetermined width into a frame shape. The oil control plate 20 is an inner surface of the peripheral wall of the tank body 11a. The plate surface is parallel to the liquid surface and is fixed by means such as multi-step welding. Here, the width and the number of mounting steps of the oil control plate 20 are appropriately set according to the size of the filter 16, the amount of hydraulic oil, the performance of the hydraulic pump, and the like.

As described above, by providing the oil control plate 20, when the return oil flows from the return pipe 13 through the return oil introduction port 15 into the tank main body 11a, the return oil and the oil control plate 20 are provided. The contact is braked and air entrapment is minimized. Moreover, this return oil also suppresses the agitation of the hydraulic oil in the tank body 11a to a minimum, and even if some air is entrained when the return oil flows in, the agitation in the tank body 11a is prevented. Since it is suppressed to a minimum and the hydraulic oil is kept almost stationary, bubbles grow and are discharged to the outside. Moreover, the air bubbles come into contact with the oil control plate 20 facing the liquid during floating, adhere to the oil control plate 20, and gradually grow to grow along the inner walls of the oil control plate 20 and the tank body 11a. As a result, it rises and is promptly released into the air. As a result, it is possible to prevent the bubbles from being included in the hydraulic oil supplied from the suction port 4 to the suction pipe 2 by promoting the discharge of the bubbles from the hydraulic oil in the tank body 11a.

Further, even if the hydraulic oil tank 10 is tilted, the hydraulic oil has a certain degree of viscosity, so that the hydraulic oil adheres to the oil control plate 20. As shown in FIG. Even if the hydraulic oil tank 10 vibrates or oscillates in an inclined state, the liquid surface does not greatly sway or undulate, and therefore the filter 16 attached to the suction port 14 is not exposed to the air. .

Next, FIG. 6 shows a second embodiment of the present invention. In the tank body 21a of the hydraulic oil tank 21 in this embodiment, a suction port 24 and a return oil introduction port 25 to which a suction pipe and a return pipe are respectively connected are formed,
A filter is attached to the suction port 24, and an atmosphere communication hole 27 is formed. In addition, the hydraulic fluid communication portion 28a,
Due to the partition plate 28 having the air communication portion 28b, the inside of the tank body 21a has a hydraulic oil outflow chamber S and a hydraulic oil inflow chamber R.
It is divided into An oil control plate 29 is attached to the partition plate 28. The oil control plate 29 is composed of plate bodies formed in a substantially U shape on both sides of the partition plate 28.

According to this structure, by providing the partition plate 28, the hydraulic oil outflow chamber S to the hydraulic oil inflow chamber R can be provided.
It takes a longer time for the hydraulic oil to move to the position where the release of bubbles can be accelerated, and even if the hydraulic oil tank 21 shakes, the liquid level in the hydraulic oil outflow chamber S greatly shakes and the filter is mounted. In addition to the function of the prior art of preventing the exposed suction port 24 from being exposed to the air as much as possible, the hydraulic oil when the hydraulic oil by the oil control plate 29 flows into the tank main body 21a. It is possible to combine the function of the above-described first embodiment that the turbulence of the liquid surface with respect to the stirring and the shaking can be minimized, which is further advantageous. When the partition plate 28 is provided as described above, the oil control plate is not necessarily provided on the hydraulic oil inflow chamber R side as long as the oil control plate is provided at least in the hydraulic oil outflow chamber S.

[0021]

As described above, according to the present invention, since the oil control plate is fixedly installed on the inner surface of the side wall of the tank body, even if the hydraulic oil tank vibrates or swings, the suction It is possible to prevent the filter provided at the mouth from being exposed to the air and to mix the air into the hydraulic oil that is supplied from the suction pipe to the hydraulic pump. The generation of bubbles due to entrainment can be suppressed, the agitation of hydraulic oil can be suppressed to a minimum, and floating bubbles will quickly adhere to the oil control plate, and hydraulic oil containing bubbles will be sent to the hydraulic pump. Since it is possible to prevent the occurrence of cavitation, various effects such as the possibility of significantly suppressing the occurrence of cavitation can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a hydraulic oil tank showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the hydraulic oil tank of FIG.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is an external view of an oil control plate.

FIG. 5 is an operation explanatory view of a hydraulic oil tank.

FIG. 6 is an explanatory diagram showing an overall configuration of a hydraulic oil tank showing a second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing an overall configuration of a hydraulic oil tank according to a conventional technique.

8 is a cross-sectional view of FIG.

FIG. 9 is an operation explanatory view of a hydraulic excavator in which a hydraulic oil tank is installed.

FIG. 10 is an operation explanatory view of the hydraulic excavator showing an operation state different from that in FIG. 9;

FIG. 11 is an operation explanatory view of a hydraulic oil tank.

[Explanation of symbols]

 11, 21 Hydraulic oil tank 11a, 21a Tank body 12 Suction pipe 13 Return pipe 14, 24 Suction port 15, 25 Return oil introduction port 16 Filter 20, 29 Oil control plate 28 Partition plate

Claims (3)

[Claims] 1. A hydraulic oil tank characterized in that an oil control plate is fixedly provided on an inner surface of a side wall of a tank main body to which a suction pipe and a return pipe are connected. 2. The oil control plate comprises a plate body having a predetermined width and formed in a frame shape. The oil control plate is provided on an inner surface of a side wall of the tank body, and the plate surface is a liquid in the tank body. The hydraulic oil tank according to claim 1, wherein the hydraulic oil tank is fixedly installed so as to be substantially parallel to the surface. 3. A partition plate is formed in the tank main body to partition into a connection part of the suction pipe and a connection part of the return pipe, and a communication hole for communicating the two chambers is formed in the partition plate. 3. The hydraulic oil tank according to claim 1, wherein the oil control plate is fixedly installed in at least one of the two chambers to which the suction pipe is connected.