JP7764767B2 - Hydraulic oil tank structure - Google Patents

Description

The present invention relates to the structure of a hydraulic oil tank mounted on a work machine such as a hydraulic excavator.

Technologies related to hydraulic oil tanks mounted on work machines such as hydraulic excavators have been proposed in the past. For example, Patent Document 1 discloses a tank device equipped with a tank body (12) that stores liquid, a suction pipe (13) through which the liquid drawn into the pump flows, and a suction filter (14) that purifies the liquid flowing through the suction pipe (13).

JP 2008-185130 A

However, water and foreign matter that gets into a hydraulic oil tank is heavier than the hydraulic oil stored in the tank, so it sinks and accumulates at the bottom of the tank.

In this regard, with conventional hydraulic oil tanks, including the hydraulic oil tank device described in Patent Document 1, it was difficult to pinpoint and remove only the water and foreign matter that had accumulated on the bottom of the tank where the hydraulic oil was stored. For this reason, when changing the hydraulic oil, the water and foreign matter had to be removed by crawling under the aircraft and cleaning the inside of the tank through a maintenance opening on the bottom of the tank.

However, because the hydraulic oil stored in the hydraulic oil tank is not replaced frequently, water and foreign matter continue to accumulate at the bottom of the tank until the hydraulic oil is replaced. The water and foreign matter that accumulates at the bottom of the tank then floats up and mixes with the hydraulic oil while the machine is in operation. As a result, the water and foreign matter may pass through the suction filter along with the hydraulic oil and enter the hydraulic circuit. If water or foreign matter enters the hydraulic circuit, it may have a negative impact on the hydraulic equipment.

The present invention therefore aims to provide a hydraulic oil tank structure that can prevent water or foreign matter that has entered the hydraulic oil tank from entering the hydraulic circuit along with the hydraulic oil.

To achieve the above object, the present invention provides a hydraulic oil tank structure comprising: a tank body including a tank bottom with an opening formed therein and for storing hydraulic oil; and a suction oil passage section provided at the tank bottom. The suction oil passage section has a suction filter for filtering the hydraulic oil and a water receiver provided integrally with the suction filter below the suction filter. The water receiver includes a container bottom and a container side with an inlet formed therein. The container bottom is located below the tank bottom. The water receiver is configured as a deposition chamber for water and foreign matter.

Here, the tank body includes a tank top surface, which is formed with a maintenance opening through which the suction filter and the water receiver can be inserted and removed, and it is preferable that the suction filter and the water receiver are provided with a removal rod for removing them from the tank body through the maintenance opening.

It is also preferable that the suction filter and the water receiver are connected via the lower end of the removal rod.

Furthermore, it is preferable that the suction filter and the water receiver are configured to be separable.

According to this invention, a water receiver for collecting water and foreign matter is provided below the suction filter and integrated with the suction filter. The bottom of the water receiver is positioned below the tank bottom, and the water receiver is configured as a deposition chamber for water and foreign matter. This allows water and foreign matter that has entered the hydraulic oil tank to be guided into the water receiver, allowing the water and foreign matter to collect within the water receiver. As a result, the water receiver can be periodically removed from the tank body, and water and foreign matter that has accumulated in the water receiver can be removed relatively frequently from above the tank. This makes it possible to prevent water and foreign matter that has entered the hydraulic oil tank from entering the hydraulic circuit along with the hydraulic oil.

1 is a vertical cross-sectional view of a hydraulic oil tank according to an embodiment of the present invention; FIG. 4 is an enlarged view of a suction oil passage portion provided in the tank bottom plate. FIG. 1 is an enlarged cross-sectional view of a suction filter. FIG. 4 is an enlarged cross-sectional view of the cylindrical tube and the water receiver. A close-up of the removal rod.

1. Embodiment
The structure of a hydraulic oil tank according to an embodiment of the present invention will be described with reference to Figures 1 to 5. In the following, a hydraulic oil tank 10 (see Figure 1) mounted on a work machine such as a hydraulic excavator will be illustrated as an example of a hydraulic oil tank.

As shown in Figure 1, the hydraulic oil tank 10 comprises a tank body 1, a suction oil passage section 2, an extraction rod 21, a suction pipe 3, an inlet pipe 7, and a return filter 8.

The tank body 1 is used to store hydraulic oil HF, which is supplied to the hydraulic circuit of a hydraulic excavator (work machine). Specifically, the tank body 1 consists of a tank bottom surface 11, tank side surfaces 13 extending upward from the tank bottom surface 11, and a tank top surface 15 located at the upper end of the tank side surfaces 13 so as to face the tank bottom surface 11.

The area surrounded by the tank bottom surface 11, tank side surface 13, and tank top surface 15 functions as a storage space SP for storing hydraulic oil HF.

An opening 11H that communicates with the suction pipe 3 is formed in the tank bottom surface 11. The suction pipe 3 is installed below the tank bottom surface 11 so as to communicate with the opening 11H in the tank bottom surface 11. As the hydraulic pump is driven, hydraulic oil HF that has passed through the suction oil passage section 2 flows into the suction pipe 3.

As shown in Figure 2, the suction pipe 3 is composed of a spacer 31, a support plate 32, a vertical plate 33, and an elbow 34.

The spacer 31 is welded to the tank bottom 11 below the tank bottom 11. The support plate 32 is fixed to the spacer 31 below the spacer 31 with bolts. The vertical plate 33 is welded to the support plate 32 below the support plate 32. The elbow 34 is an L-shaped pipe and is fixed to the vertical plate 33.

Referring again to Figure 1. As shown in Figure 1, an inlet pipe 7 penetrates the tank side surface 13. Return oil from each hydraulic actuator mounted on the hydraulic excavator flows into the inlet pipe 7.

Return oil that flows into the inlet pipe 7 flows into an area AR formed within the tank body 1. A return filter 8 is installed in area AR to filter the return oil from each hydraulic actuator. The return oil from each hydraulic actuator is filtered by the return filter 8 before returning to the storage space SP in the tank body 1.

A maintenance opening 15H is formed on the tank top surface 15. When the machine is operating, a cover member 151 is attached to the maintenance opening 15H.

The upper recess of the vertically elongated removal rod 21 is inserted into and supported by the lower protrusion of the lid member 151. The removal rod 21 will be described in more detail later.

The suction oil passage section 2 is installed on the tank bottom surface 11 so as to cover the opening 11H (see Figure 1). As shown in Figure 2, the suction oil passage section 2 is composed of a suction filter 4, a cylindrical tube 5 placed inside the suction filter 4, and a water receiver 6 provided below the suction filter 4.

As shown in Figure 3, the suction filter 4 comprises a filter section 40 for filtering the hydraulic oil HF, a flow pipe 41 arranged inside the filter section 40, and a gasket 43 provided below the filter section 40.

Multiple openings 41H are formed on the outer circumferential surface of the flow pipe 41. The multiple openings 41H are through-holes that allow the hydraulic oil HF filtered by the filter section 40 to pass through to the inside of the flow pipe 41.

Note that in Figures 2 and 3, for ease of viewing, the opening 41H is shown only on a portion of the outer surface of the flow pipe 41, but in reality, the opening 41H is formed over the entire surface.

In addition, an insertion hole 4H is formed in the center of the top of the suction filter 4, through which the lower end of the removal rod 21 can be inserted. On the other hand, the lower end of the suction filter 4 has a large opening so that the cylindrical tube 5 can be inserted and removed.

The diameter D1 of the suction filter 4 is smaller than the maintenance opening 15H (see Figure 1) on the tank top surface 15. This allows the suction filter 4 to be removed from the tank body 1 to the outside through the maintenance opening 15H.

As shown in Figure 4, the cylindrical tube 5 is composed of a cylindrical member that is long in the vertical direction. The diameter D2 of the cylindrical tube 5 is smaller than the diameter of the flow pipe 41 that forms part of the suction filter 4. Therefore, the cylindrical tube 5 can be placed inside the flow pipe 41.

Multiple openings 51H are formed on the outer surface of the cylindrical tube 5 in an area higher than the water receiver 6. The multiple openings 51H are through-holes that allow the hydraulic oil HF that flows in through the flow pipe 41 of the suction filter 4 to pass further inside the cylindrical tube 5.

Note that in Figures 2 and 4, for ease of viewing, the opening 51H is shown only on a portion of the outer surface of the cylindrical tube 5, but in reality, the opening 51H is formed over the entire surface.

On the other hand, the area of the outer surface of the cylindrical tube 5 that is lower than the water receiver 6 functions as part of the side surface of the water receiver 6. Therefore, multiple openings 51H are not formed in the area of the outer surface of the cylindrical tube 5 that is lower than the water receiver 6.

In addition, a female thread FS is formed in the center of the upper part of the cylindrical tube 5, which can be threaded onto the male thread MS (see Figure 5) formed at the lower end of the removal rod 21.

As shown in Figure 4, the water receiver 6 is arranged to surround a portion of the lower end of the outer periphery of the cylindrical tube 5 and functions as a deposition chamber in which water and foreign matter accumulate.

The water receiver 6 is composed of a container bottom surface 61, a container side surface 62, and a filter support portion 63. As mentioned above, a portion of the lower end of the outer circumferential surface of the cylindrical tube 5 also functions as the inner surface of the water receiver 6.

The container bottom surface 61 extends outward in a generally horizontal direction from the lower end of the cylindrical tube 5. The end of the container bottom surface 61 facing the cylindrical tube 5 is welded to the outer peripheral surface of the cylindrical tube 5.

As shown in Figure 2, when the suction oil passage section 2 is installed, the container bottom surface 61 is positioned lower than the tank bottom surface 11.

As shown in Figure 4, multiple intake ports 62H are formed on the upper end of the container side surface 62 for taking in water and foreign matter into the water receiver 6. The multiple intake ports 62H are arranged at intervals around the container side surface 62.

As shown in Figure 2, when the suction oil passage section 2 is installed, all of the multiple intake ports 62H are located near the tank bottom surface 11.

As shown in Figure 4, the filter support portion 63 is configured as an L-shaped cross-section member that bends and extends outward from the upper end of the container side surface 62, and then bends and extends upward.

The suction filter 4 is placed on the horizontal surface of the filter support portion 63 so that the packing 43 (see Figure 3) is in close contact with it. With this configuration, the water receiver 6 is provided integrally with the suction filter 4 below it.

As shown in Figure 5, the lower end of the removal rod 21 is formed with a male thread MS that can be threaded into a female thread FS (see Figure 4) formed in the center of the upper part of the cylindrical tube 5.

As shown in Figure 2, the male thread MS (see Figure 5) formed on the lower end of the removal rod 21 is inserted into the insertion hole 4H (see Figure 3) of the suction filter 4 and threaded into the female thread FS (see Figure 4) of the cylindrical tube 5. This connects the suction filter 4 and the cylindrical tube 5 via the removal rod 21. Note that, because the cylindrical tube 5 and the water receiver 6 are configured as a single member, it can also be said that the suction filter 4 and the water receiver 6 are connected by the removal rod 21.

When the suction filter 4 and water receiver 6 are connected by the removal rod 21, the water receiver 6 is integrally provided below the suction filter 4.

Furthermore, by removing the male thread MS of the removal rod 21 that is threaded into the female thread FS of the cylindrical tube 5 (releasing the threaded state), the connection between the suction filter 4 (Figure 3), the cylindrical tube 5, and the water receiver 6 (Figure 4) is released. In this way, in this embodiment, the suction filter 4 and the water receiver 6 are configured to be separable.

In the above-described embodiment, a water receiver 6 for collecting water and foreign matter is provided integrally with the suction filter 4 below the suction filter 4. Furthermore, the container bottom surface 61 of the water receiver 6 is positioned below the tank bottom surface 11.

This allows water and foreign matter that has entered the hydraulic oil tank 10 to be guided into the water receiver 6, where it can be collected. As a result, the water receiver 6 can be periodically removed from the tank body 1, allowing the water and foreign matter that has accumulated in the water receiver 6 to be removed relatively frequently from the top of the tank. This makes it possible to prevent water and foreign matter that has entered the hydraulic oil tank 10 from entering the hydraulic circuit along with the hydraulic oil HF.

In particular, in the above-described embodiment, the container bottom surface 61 of the water receiver 6 is positioned below the tank bottom surface 11, making it easier for water and foreign objects to enter but more difficult for them to exit, thereby preventing water and foreign objects from floating when the machine is shaking.

Furthermore, according to the above-described embodiment, since the water receiver 6 is located in the suction oil passage section 2, water and foreign matter are likely to collect in the water receiver 6 along with the flow of hydraulic oil HF when the hydraulic pump is operating, and the water and foreign matter capture efficiency is higher than when the water receiver 6 is located in a different location.

Furthermore, according to the above-described embodiment, the water receiver 6 can be removed from the tank body 1 via the removal rod 21, so water and foreign matter can be removed without draining the hydraulic oil HF. This eliminates the need to prepare an oil drain container to store the hydraulic oil HF drained from the tank body 1.

In particular, in the above-described embodiment, the water receiver 6 can be removed through the maintenance opening 15H formed in the tank top surface 15, which avoids the need to drain oil below the hydraulic oil tank 10 and eliminates the need for the operator to crawl under the machine.

Furthermore, the water receiver 6 can be removed from the tank body 1 using the maintenance opening 15H for removing the suction filter 4.

Furthermore, according to the above-described embodiment, the suction filter 4 and the water receiver 6 are configured to be disassembled, so water and foreign matter accumulated in the water receiver 6 can be easily drained, making it easy to clean the inside of the water receiver 6.

Furthermore, according to the above-described embodiment, a cylindrical tube 5 is placed inside the suction filter 4, which creates a larger opening on the bottom side of the suction filter 4 compared to conventional filters. This makes it easier to clean the inside of the suction filter 4.

Furthermore, according to the above-described embodiment, the suction filter 4 and the water receiver 6 are connected by the removal rod 21, so there is no need to provide a separate part to connect the two. This reduces the number of parts and improves ease of use.

2. Modified Examples
The structure of the hydraulic oil tank according to the present invention is not limited to the above-described embodiment, and various modifications and improvements are possible within the scope of the claims.

For example, in the above-described embodiment, the cylindrical tube 5 is placed inside the suction filter 4, but this is not limiting. If the water receiver 6 is placed below the suction filter 4, the cylindrical tube 5 does not necessarily need to be provided.

As described above, the hydraulic oil tank structure of the present invention is suitable for hydraulic oil tanks mounted on work machines such as hydraulic excavators.

1 Tank body 2 Suction oil passage section 3 Suction pipe 4 Suction filter 4H Insertion hole 5 Cylindrical pipe 6 Water receiver 7 Inlet pipe 8 Return filter 10 Hydraulic oil tank 11 Tank bottom surface 11H Opening 13 Tank side surface 15 Tank top surface 15H Maintenance opening 21 Removal rod 31 Spacer 32 Support plate 33 Vertical plate 34 Elbow 40 Filter section 41 Flow pipe 41H Opening 43 Gasket 51H Opening 61 Container bottom surface 62 Container side surface 62H Intake port 63 Filter support section 151 Lid member FS Female thread HF Hydraulic oil MS Male thread SP Storage space

Claims (4)

A hydraulic oil tank structure,
a tank body including a tank bottom surface having an opening formed therein and configured to store hydraulic oil;
a suction oil passage portion provided on the bottom surface of the tank;
Equipped with
The suction oil passage portion is
a suction filter that filters the hydraulic oil;
a water receiver provided integrally with the suction filter below the suction filter,
The water receiver includes a bottom surface and a side surface having an inlet formed therein;
the container bottom surface is located below the tank bottom surface,
A hydraulic oil tank structure characterized in that the water receiver is configured as a chamber for accumulating water and foreign matter. The tank body includes a tank upper surface,
A maintenance opening through which the suction filter and the water receiver can be inserted and removed is formed on the top surface of the tank,
2. The hydraulic oil tank structure according to claim 1, wherein the suction filter and the water receiver are provided with a removal rod for removing them to the outside of the tank body through the maintenance opening. The hydraulic oil tank structure described in claim 2, characterized in that the suction filter and the water receiver are connected via the lower end of the removal rod. The hydraulic oil tank structure described in any one of claims 1 to 3, characterized in that the suction filter and the water receiver are configured to be separable.