JP4307278B2 - Oil tank and moving body - Google Patents

Description

  The present invention relates to an oil tank that stores hydraulic fluid.

  Conventionally, in vehicles equipped with a mechanism that operates with hydraulic fluid (hydraulic oil) such as a forklift, an oil tank for circulating the air inside the oil tank is attached to the oil tank that stores the hydraulic fluid. Thus, when the hydraulic fluid sent to the mechanism side returns, the air present in the oil tank can be pushed out to the outside by the pressure of the hydraulic fluid.

  In this type of vehicle, the hydraulic fluid in the oil tank may block the air flow path in the air breather depending on the operation state of the vehicle itself, and this situation returns the hydraulic fluid sent to the mechanism side. If it occurs at the timing, the hydraulic fluid may be discharged to the outside of the oil tank through the air breather.

As a technique for preventing such discharge of hydraulic fluid, for example, the inside of the tank and the air breather are communicated via a cylindrical member (adapter) that is fixed to the upper portion of the oil tank (hydraulic fluid tank) and extends in the vertical direction In addition, a structure has been proposed in which a plate facing the front end of the tubular member with a predetermined interval is fixed to the inner peripheral surface of the oil tank in a horizontal state inside the oil tank (Patent Document). 1). In addition, as a similar technique, a structure is proposed in which the upper wall of the oil tank and the liquid level of the hydraulic fluid are partitioned by a plate (partition plate) in which a vent hole is formed at a position away from the air breather. (See Patent Document 2).
Japanese Patent Laid-Open No. 07-286601 Japanese Utility Model Publication No. 05-017201

However, in the structure as described above, it is not possible to sufficiently prevent the air flow path from being blocked, and there is a possibility that the working fluid is discharged to the outside of the oil tank through the air blizzer.
First, in the structure of Patent Document 1, since the lower end side of the cylindrical member to which the air blizzer is attached is isolated from the liquid level of the working fluid by a plate fixed at a distance from this lower end, It is considered that the hydraulic fluid coming from the lower end side of the cylindrical member prevents the air flow path from being blocked. However, in this structure, it cannot be said that there is no possibility that the air flow path is blocked by the hydraulic fluid coming from the lateral direction of the cylindrical member. If this situation occurs at the timing when the working fluid sent to the mechanism returns, the working fluid may be discharged to the outside through the air blizzard.

  Further, in the structure of Patent Document 2, the path from the air breather to the liquid level of the hydraulic fluid is long because it passes through the vent hole. It is thought that it is prevented from being released into the water. However, in this structure, there is a possibility that the working fluid may remain in the path from the vent hole to the air blizzard, and it cannot be said that there is no possibility that the vent hole is further blocked by the working fluid in this state. When this situation occurs at the timing when the working fluid sent to the mechanism returns, the stopped working fluid may reach the air breather and be discharged to the outside.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a technique for preventing the hydraulic fluid from being discharged to the outside of the oil tank through the air blizzer.

  The purpose of the present invention is to prevent the hydraulic fluid from being sufficiently prevented from being released by the structure around the air breather in the prior art, and to prevent the hydraulic fluid from coming in and block the air flow path. However, this is based on the idea that it is difficult to sufficiently prevent the working fluid flowing irregularly in the oil tank. That is, the present invention does not aim to reliably prevent the arrival of the hydraulic fluid as in the prior art, but by ensuring the air flow path even if the hydraulic fluid arrives, It was made with the aim of preventing the release.

First, the present applicant, as a first structure, a tank body for storing the work Doeki, a hollow cylindrical member that extends from the exterior to the interior of the tank body, said to be located outside the tank body The present inventors have conceived an oil tank which is attached to an end portion side of a cylindrical member and includes an air blizzer that circulates air from the inside of the tank body to the outside through the cylindrical member. In this oil tank, the cylindrical member is a portion located inside the tank main body, and a position higher than a hydraulic fluid level that becomes a liquid level of the hydraulic fluid when the hydraulic fluid is stored in the tank main body. A cylindrical vent hole extending from the outer peripheral portion to the inner peripheral portion of the cylindrical member is formed in the portion, and the tank body has a position higher than the hydraulic fluid level in the outer peripheral portion of the cylindrical member. A wall member arranged so as to surround the portion to be formed is provided, and a wall vent hole extending from the front surface portion to the back surface portion of the wall member is formed in the wall member.

As a second structure, a tank body for storing the work Doeki, a hollow cylindrical member that extends from the exterior to the interior of the tank body, an end of the tubular member located outside of the tank body The present invention has been conceived of an oil tank that is attached to a portion side and includes an air breather that circulates air from the inside of the tank main body to the outside through the cylindrical member. In this oil tank, the cylindrical member has a length that does not reach the hydraulic fluid level as the hydraulic fluid level in the state where the hydraulic fluid is stored in the tank main body at the end located on the inside of the tank main body. And a cylindrical vent hole extending from the outer peripheral portion to the inner peripheral portion of the cylindrical member is formed in a portion located inside the tank main body. The wall member arrange | positioned so that the outer peripheral part of a shaped member may be enclosed is provided.

Further, as the third structure, a tank body for storing the previous SL hydraulic fluid, a hollow cylindrical member that extends from the exterior to the interior of the tank body, the tubular member located outside of the tank body The present inventors have conceived an oil tank that is attached to the end side and includes an air blizzer that circulates air from the inside of the tank body to the outside through the cylindrical member. In this oil tank, a space isolated by the wall member is formed around the cylindrical member by surrounding the cylindrical member with a cylindrical wall member closed at one end. Further, the wall member is formed with a wall vent hole extending from the outer peripheral portion to the inner peripheral portion in the outer peripheral portion along the length direction.

If the oil tank has the structure as described above, the release of the hydraulic fluid to the outside of the oil tank can be sufficiently prevented as shown by the result of the durability test described later.
By the way, if the cylindrical member in the first structure described above has a structure that can prevent the flow of hydraulic fluid from the end portion on the side located inside the oil tank to the air breather side, it is good in the durability test. It turns out that it brings results. Specifically, for example, may end on the side located inside the front Symbol tank body has a length which reaches to a position lower than the operation fluid, to such structures.

  With this structure, since the end of the cylindrical member located inside the tank body is immersed in the hydraulic fluid, the hydraulic fluid flows into the inner peripheral portion on the end of the cylindrical member. However, the hydraulic fluid present on the inner peripheral side of the cylindrical member is thus less affected by the flow state of the hydraulic fluid existing outside the cylindrical member by being separated by the cylindrical member. . Therefore, even if the hydraulic fluid inside the tank body largely flows, the hydraulic fluid present on the inner peripheral side of the cylindrical member does not flow greatly according to it, and the end on the side of the cylindrical member located inside the tank main body It can be expected that the flow of hydraulic fluid from the part to the air breather side is hindered.

Further, the tubular member, as a structure capable of preventing the flow of hydraulic fluid from the end on the side located inside the oil tank to Eaburiza side, end on the side located inside the front Symbol tank body is closed You may make it the structure of having become the shape formed.

With this structure, the end of the tubular member on the side located inside the tank main body is closed, so that the inflow of hydraulic fluid from the end can be reliably prevented.
The first was described above, in the second structure, the tubular vent holes are formed in the tubular member, the total area of the cylindrical vent, for example, perpendicular to the longitudinal direction of this cylindrical member It is good to comprise so that it may become more than the area of the hollow part in the cross section to perform.

  With this structure, even when the end of the cylindrical member is blocked by the hydraulic fluid or in a closed shape, the air flow path to the air blizzer is in the length direction of the cylindrical member. More than the same area as the hollow part in an orthogonal cross section can be ensured.

The first was described above, in the second structure, the tubular member, it is desirable that the two or more cylindrical vents even without less is formed. With this structure, there are a plurality of air flow paths through the cylinder vents, and therefore, it is difficult for all of the air flow paths to be blocked by the hydraulic fluid.

In the first, third structure mentioned above, the wall member, it is desirable that two or more of the wall vent hole is formed even without low. With this structure, there are a plurality of air flow paths through the wall vents, and therefore, it is difficult for all the air flow paths to be blocked by the hydraulic fluid.

In addition, a moving body for solving the above-described problem is a moving body that includes an operating mechanism that operates with a hydraulic fluid stored in an oil tank, and the oil tank includes any of the oil tanks described above. It is characterized by that.

In the case of a moving body configured in this way, the hydraulic fluid can be prevented from being discharged by any of the oil tanks described above . For example, the vicinity of the oil tank and thus the moving body is contaminated by the hydraulic fluid. Can be prevented.

In particular, in a moving body configured to carry a load by an operating mechanism, it may move while operating the operating mechanism, so that the hydraulic fluid in the oil tank flows irregularly, and the conventional oil If it is a tank, it will become easy to discharge | release hydraulic fluid via an air blizzard. For this reason, when the cargo to be carried is one that cannot tolerate contamination (for example, food), it is difficult to use a moving body that includes an oil tank that may release hydraulic fluid. In addition, the installation location of the oil tank from which the hydraulic fluid may be released is limited to some extent so that the released hydraulic fluid does not cause discomfort or health damage to the operator. However, if the oil tank is provided with any of the oil tanks as described above, the hydraulic fluid can be prevented from being discharged from the oil tank. It can be transported without being contaminated. Moreover, even if an oil tank is installed in the vicinity of the operator of the moving body, there is no fear of causing discomfort or health damage due to the hydraulic fluid.

Embodiments of the present invention will be described below with reference to the drawings.
The forklift 1 is a so-called reach type that is operated by an operator in a standing posture, and includes an operating mechanism that operates with hydraulic fluid (hydraulic oil) stored in an oil tank 2 as shown in FIG. Is. FIG. 1 shows a state in which the operating mechanism is removed so that the position of the oil tank 2 is clear.

  As shown in FIG. 2, the oil tank 2 provided in the forklift 1 includes a tank body 10 that stores hydraulic fluid, a hollow cylindrical member 20 that extends from the upper part of the tank body 10 toward the inside of the tank body 10, An air breather 30, which is attached to the end (upper end) side of the tubular member 20 located outside the tank body 10 and circulates air from the inside of the tank body 10 to the outside via the tubular member 20, A suction pipe 40 for sending the stored working fluid to the working mechanism, a return pipe 50 for introducing the working fluid returning from the working mechanism into the tank body 10, and an oil inlet for injecting the working fluid into the tank body 10 60, a level gauge 70 for checking the level of the hydraulic fluid stored in the tank body 10 is provided. In addition, the cylindrical member 20 mentioned above is comprised by the cylindrical pipe.

Hereinafter, embodiments in which the mounting structure of the tank main body 10, the cylindrical member 20, and the air breather 30 in the oil tank 2 are different will be described.
[First Embodiment]
In the present embodiment, as shown in FIG. 3, the cylindrical member 20 has a working fluid liquid in a state where the end portion (lower end) on the side located inside the tank body 10 stores the working fluid in the tank body 10. It has a length that reaches a position lower than the surface (hereinafter referred to as “operating fluid level”) S. A circular tube vent 24 extending from the outer peripheral portion to the inner peripheral portion is provided in a portion located inside the tank body 10 and higher than the hydraulic fluid level S in the length direction (vertical direction in FIG. 3). A plurality of (eight in the present embodiment) are formed along the circumferential direction in the cross section orthogonal to. These cylinder vent holes 24 are arranged at positions facing each of the other cylinder vent holes 24 (see oil tank G in FIG. 7). The total (total area) of the areas of the cylinder vent holes 24 (the area of the cylinder vent holes 24 in a plane orthogonal to the direction of entry and exit when air enters and exits the cylinder vent holes 24) is the length of the cylindrical member 20. It is comprised so that it may become the same area as the hollow part (namely, inner periphery) in the cross section orthogonal to a direction.

  In addition, as shown in FIG. 3, the tank body 10 has a cylindrical shape that is disposed so as to surround the outer periphery of the portion of the cylindrical member 20 that is positioned higher than the hydraulic fluid level S. The wall member 80 is provided so as to extend downward.

  The wall member 80 has a plurality of circular wall vent holes 82 extending from the outer peripheral portion to the inner peripheral portion along the circumferential direction in the cross section perpendicular to the length direction (vertical direction in FIG. 3) (this embodiment). 4 are formed) (see oil tank G in FIG. 7). These wall vents 82 are arranged at positions facing each of the other wall vents 82.

[Second Embodiment]
In the present embodiment, as shown in FIG. 4, the tubular member 20 has a shape in which an end (lower end) on the side located inside the tank body 10 is closed by a bottom lid 26, and this end However, it has such a length that it does not reach the liquid level (hydraulic liquid level) S of the hydraulic fluid in a state where the hydraulic fluid is stored in the tank body 10. And in the part located in the inside of the tank main body 10, the circular pipe | tube ventilation hole 24 from an outer peripheral part to an inner peripheral part follows the circumferential direction in the cross section orthogonal to a length direction (up-down direction in FIG. 4). A plurality (eight in the present embodiment) are formed (see the oil tank H in FIG. 7). These cylinder vent holes 24 are arranged at positions facing each of the other cylinder vent holes 24. Note that the total (total area) of the areas of the cylinder vent holes 24 (the area of the cylinder vent holes 24 in a plane orthogonal to the entrance / exit direction when air enters and exits the cylinder vent holes 24) is the length of the cylindrical member 20 It is comprised so that it may become the same area as the hollow part (namely, inner periphery) in the cross section orthogonal to a vertical direction.

Further, as shown in FIG. 4, a cylindrical wall member 80 disposed so as to surround the outer periphery of the cylindrical member 20 is provided inside the tank body 10.
The wall member 80 has a plurality of circular wall vent holes 82 extending from the outer peripheral portion to the inner peripheral portion along the circumferential direction in a cross section orthogonal to the length direction (vertical direction in FIG. 3). In the embodiment, four) are formed. These wall vents 82 are arranged at positions facing each of the other wall vents 82 (see oil tank H in FIG. 7).

[Third Embodiment]
In the present embodiment, as shown in FIG. 5, the cylindrical member 20 has a working fluid liquid in a state where the end (lower end) on the side located inside the tank body 10 stores the working fluid in the tank body 10. The surface does not reach the surface (hydraulic fluid surface) S. And in the part located in the inside of the tank main body 10, the circular cylinder vent hole 24 from an outer peripheral part to an inner peripheral part follows the circumferential direction in the cross section orthogonal to a length direction (up-down direction in FIG. 5). A plurality (eight in this embodiment) are formed (see oil tank D in FIG. 7). These cylinder vent holes 24 are arranged at positions facing each of the other cylinder vent holes 24. Note that the total (total area) of the areas of the cylinder vent holes 24 (the area of the cylinder vent holes 24 in a plane orthogonal to the entrance / exit direction when air enters and exits the cylinder vent holes 24) is the length of the cylindrical member 20 It is comprised so that it may become the same area as the hollow part (namely, inner periphery) in the cross section orthogonal to a vertical direction.

Further, inside the tank body 10, as shown in FIG. 5, a cylindrical wall member 80 is provided so as to surround the outer periphery of the cylindrical member 20.
[Fourth Embodiment]
In the present embodiment, as shown in FIG. 6, the cylindrical member 20 has only a length that the end (lower end) on the side not located outside the tank body 10 reaches the inner wall of the tank body 10. It does not extend into the tank body 10.

Further, as shown in FIG. 6, a cylindrical wall member 80 disposed so as to surround the outer periphery of the cylindrical member 20 is provided inside the tank body 10.
The wall member 80 has a plurality of circular wall ventilation holes 82 extending from the outer peripheral portion to the inner peripheral portion along the circumferential direction in a cross section perpendicular to the length direction (vertical direction in FIG. 6). 4 in the embodiment) (see oil tank C in FIG. 7). These wall vents 82 are arranged at positions facing each of the other wall vents 82. Further, the wall member 80 has a shape in which the end (lower end) side near the liquid level (hydraulic liquid level) S of the hydraulic fluid in a state where the hydraulic fluid is stored in the tank body 10 is closed by the bottom lid 86. It has become.

[effect]
If the oil tank 2 has the structure shown in each of the above-described embodiments, the release of the hydraulic fluid to the outside of the oil tank 2 can be sufficiently prevented as shown by the result of the durability test described later.

  In the oil tank 2 in the first embodiment described above, the lower end of the cylindrical member 20 is immersed in the hydraulic fluid, so that the hydraulic fluid flows into the inner peripheral portion on the lower end side of the cylindrical member 20. However, the hydraulic fluid present in the inner peripheral portion of the cylindrical member 20 is thus separated by the cylindrical member 20, thereby affecting the influence of the hydraulic fluid existing outside the cylindrical member 20 from the flow state. It becomes difficult to receive. Therefore, even if the hydraulic fluid in the tank main body 10 flows greatly, it does not flow in accordance with it, and the flow of hydraulic fluid from the lower end side to the air breather 30 side can be prevented.

Moreover, in the oil tank 2 in 2nd Embodiment mentioned above, since the lower end side of the cylindrical member 20 is closed, the inflow of the hydraulic fluid from a lower end side can be prevented reliably.
Further, in the first to third embodiments described above, the total area of the tube vents 24 formed in the tubular member 20 is the same as the hollow portion in the cross section orthogonal to the length direction of the tubular member 20. Because of the area, the air breather is also used when the lower end of the cylindrical member 20 is closed with the hydraulic fluid (first and third embodiments) or in a closed shape (second embodiment). The air flow path up to 30 can be ensured by the same area as the hollow portion in the cross section orthogonal to the length direction of the cylindrical member 20.

  Further, in the first to third embodiments described above, since the plurality of tube vent holes 24 are formed in the tubular member 20, by providing a plurality of air flow paths through the tube vent holes 24, It is possible to make it difficult for all the air flow paths to be blocked by the working fluid.

  In the first, second, and fourth embodiments described above, a plurality of wall ventilation holes 82 are formed in the wall member 80, so that a plurality of air flow paths through the wall ventilation holes 82 exist. Thus, it is possible to make it difficult for all the air flow paths to be blocked by the hydraulic fluid.

  Further, the oil tank 2 described above only needs to have a height from the hydraulic fluid level S in the tank body 10 so that the cylindrical member 20 and the wall member 80 can be disposed, and the hydraulic fluid flowing inside the tank body 10 does not reach. Since it is not necessary to secure a sufficient height, the oil tank 20 itself can be downsized. Moreover, since it is not the structure which arrange | positions the member which partitions off the space on the hydraulic fluid level S inside the tank main body 10 like the structure described in patent document 1, patent document 2, compared with these structures. Also, the oil tank 20 can be downsized.

  In addition, since the forklift 1 having the oil tank 2 described above can prevent the hydraulic fluid from being discharged from the oil tank 2, for example, the vicinity of the oil tank 2 and the vicinity of the forklift 1 are contaminated by the hydraulic fluid. Can be prevented.

  Further, since the forklift 1 is a reach type that has a large demand for miniaturization, as shown in FIG. 1, the oil tank 2 cannot often be installed at a free position. In such a case, if there is a risk of the hydraulic fluid being released from the oil tank 2, there is a risk of contaminating the cargo to be transported. Is difficult to use. Further, the installation location of the oil tank 2 is limited to some extent so that the discharged hydraulic fluid does not cause discomfort and health damage to the operator. However, if the forklift 1 includes the oil tank 2 described above, it is possible to prevent the hydraulic fluid from being discharged from the oil tank 2, so that even cargo that cannot be contaminated is not contaminated by the hydraulic fluid. You will be able to carry it. Moreover, even if the oil tank 2 is installed in the vicinity of the operator of the forklift 1, there is no fear of causing discomfort or health damage due to the hydraulic fluid.

  In addition, forklifts, such as cranes and construction machines, move in such a way that the operation mechanism and the vehicle itself do not move at the same time, or the operation mechanism moves slowly and constantly. Unlike the body, it is common to move with the action of an abrupt operation mechanism, so the hydraulic fluid inside the oil tank is likely to fluctuate irregularly. For this reason, it is effective to employ, in the forklift, an oil tank that does not release hydraulic fluid through an endurance test described later, such as the oil tank 2 of the present embodiment. Further, among the forklifts, the reach type forklift 1 as in the present embodiment reciprocates in a narrow place with a sudden operation mechanism as compared with a forklift other than the reach type (so-called counter type). Since the hydraulic fluid in the oil tank is more likely to fluctuate more irregularly, the oil tank 2 in which the hydraulic fluid is not released through the durability test described below is used in a reach-type forklift. It can be said that the effect is great.

[Modification]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various forms can be taken as long as they belong to the technical scope of the present invention. .

  For example, in each of the embodiments described above, the reach type forklift 1 is used as the moving body of the present invention, and the oil tank of the present invention is applied to the forklift 1. However, the oil tank of the present invention is a reach type. The present invention can be applied not only to other forklifts but also to other moving bodies having an operation mechanism that operates with hydraulic fluid.

  Further, in each of the above-described embodiments, the total area of the tube vents 24 formed in the tubular member 20 is the same as that of the hollow portion in the cross section perpendicular to the length direction of the tubular member 20. What was comprised was illustrated. However, the total area of the tube vents 24 may not be the same as the hollow part as long as the area of the air breather 30 is sufficient to allow air to flow sufficiently, and is larger than the area of the hollow part. You may comprise so that it may become, and you may comprise so that it may become small.

  Moreover, in 2nd Embodiment mentioned above, although the length from which the lower end of the cylindrical member 20 reaches | attains only to the position higher than the hydraulic fluid level S was illustrated, this lower end is rather than the hydraulic fluid level S. It is good also as what has the length which reaches | attains a low position.

  Further, in the second embodiment described above, the cylinder vent hole 24 formed in the cylindrical member 20 may be formed so that a part of the cylinder vent hole 24 is at the same height as the upper surface of the bottom lid 26. . If the cylinder vent hole 24 is formed in this manner, even if the hydraulic fluid stays at the bottom of the cylindrical member 20, the hydraulic fluid can return to the tank body 10 through the cylindrical vent hole 24. Therefore, it is possible to prevent the hydraulic fluid from remaining on the bottom of the cylindrical member 20. In this case, by forming the tube vent 24 so as to incline from the upper surface of the bottom lid 26 toward the inside of the tank body 10 (for example, a tapered hole), this effect becomes more remarkable. Can do.

  In the fourth embodiment described above, the wall vent 82 formed in the wall member 80 may be formed such that a part of the wall vent 82 is at the same height as the upper surface of the bottom lid 86. By forming the wall vent 82 in this way, even if the hydraulic fluid stays at the bottom of the wall member 80, the hydraulic fluid can return to the inside of the tank body 10 through the wall vent 82. Therefore, it is possible to prevent the hydraulic fluid from remaining on the bottom of the wall member 80. In this case, the wall ventilation hole 82 is formed so as to be inclined from the upper surface of the bottom lid 86 toward the inside of the tank body 10 (for example, a tapered hole), thereby making this effect more remarkable. Can do.

  Moreover, in each embodiment mentioned above, what was arrange | positioned in the position which each cylinder ventilation hole 24 formed in the cylindrical member 20 opposes either of the other cylinder ventilation holes 24 was illustrated. However, each of the cylinder vent holes 24 does not face the other cylinder vent holes 24. In other words, the extension line of the central axis in the direction of entering and exiting when the air enters and exits is the extension of the central axis in the other cylinder vent holes 24. You may arrange | position in the position which is not parallel to a line.

[An endurance test]
Below, the applicant of the present invention aims to prevent the release of hydraulic fluid by ensuring the air flow path even when the hydraulic fluid arrives in the vicinity of the air breather in the oil tank. An endurance test performed on the oil tank will be described.

  This durability test was performed based on “MIL-STD-268C” defined as a level required for vehicles in MIL (military specifications and standards) standards. This standard requires that the state of each part satisfies a predetermined condition after traveling a predetermined course while operating each part of the vehicle. For forklifts equipped with different oil tanks (oil tanks A to H), check whether the hydraulic fluid is released from the oil tanks until each part of the forklift is operated and the predetermined course is completed Then, the durability test was performed by performing this 20 times. The forklift used in this durability test is the one shown in the above embodiment.

Such a durability test was performed on a forklift equipped with oil tanks A to H shown below (see FIG. 7).
Oil tank A: The cylindrical member 20 has a length that allows the end (lower end) on the side not located outside the tank body 10 to reach the inner wall of the tank body 10. The structure does not extend. Further, the wall member 80 is not provided. Note that this structure has been conventionally employed.
Oil tank B: A structure in which a cylindrical wall member 80 arranged so as to surround the outer periphery of the cylindrical member 20 is provided inside the tank body 10 in the oil tank A.
Oil tank C: The oil tank B has a structure in which the lower end of the wall member 80 in the oil tank B is closed by the bottom lid 86, and the wall member 80 is formed with four wall vent holes 82. It is the structure shown in the form.
Oil tank D: It is assumed that the cylindrical member 20 in the oil tank B is extended into the tank body 10 and has a length that the lower end side does not reach the hydraulic fluid level S. From the hydraulic fluid level S in the cylindrical member 20 In this structure, eight cylindrical vent holes 24 are formed at a high position, and four wall vent holes 82 are formed in the wall member 80.
Oil tank E: A structure in which the wall member 80 is removed from the oil tank D.
Oil tank F: A cylindrical wall member 80 disposed so as to surround the outer periphery of the cylindrical member 20 is provided inside the tank body 10 in the oil tank E, and four wall vent holes 82 are provided in the wall member 80. It is a formed structure.
Oil tank G: a structure in which four wall vents 82 are formed in the wall member 80 of the oil tank F, and the structure shown in the first embodiment described above.
Oil tank H: The cylindrical member 20 in the oil tank G has a length that allows the lower end side to reach a position higher than the hydraulic fluid level S (shortened), and the lower end is closed by the bottom lid 26. This is the structure shown in the second embodiment described above.

As a result of the endurance test for these oil tanks, as shown in FIG. 8, no hydraulic fluid was released for the oil tanks C, D, G, and H.
In addition, the durability test is performed on the oil tank G even when the number of the wall vents 82 is reduced. As a result, if two or more (that is, a plurality) of the wall vents 82 are formed, the hydraulic fluid is not used. It was never released.

  Further, regarding the oil tank D, when the durability test was performed on the structure in which the number of the wall vents 82 was reduced, the wall vent 82 was “0”, that is, the wall vent 82 was not formed. However, the hydraulic fluid was not released. From this, it is understood that the wall vent 82 need not be formed for the oil tank D. Note that the structure in which the wall vent 82 is not formed in this way is the structure shown in the third embodiment described above.

  Among these, for the oil tank G, the lower end side of the cylindrical member 20 is immersed in the hydraulic fluid, so that the hydraulic fluid flows into the inner peripheral portion on the end side of the cylindrical member 20. However, since the hydraulic fluid present on the inner peripheral side of the cylindrical member 20 is separated by the cylindrical member 20, the hydraulic fluid is less affected by the flow state of the hydraulic fluid existing outside the cylindrical member 20. Therefore, even if the hydraulic fluid inside the tank body 10 flows greatly, the hydraulic fluid present on the inner peripheral side of the cylindrical member 20 does not flow greatly according to it, and the air blizzer 30 side from the lower end side of the cylindrical member 20. It is expected that the flow of hydraulic fluid into the tank is hindered. Further, as for the oil tank H, since the lower end of the cylindrical member 20 is closed by the bottom lid 26, it is clear that the inflow of hydraulic fluid from the lower end side of the cylindrical member 20 to the air breather 30 side is obstructed. It is. As described above, with respect to the oil tanks G and H, the result of the durability test was improved due to the fact that the inflow of the hydraulic fluid from the lower end side of the tubular member 20 to the air breather 30 side was hindered. Can be guessed.

Perspective view showing forklift Three side view showing oil tank Sectional drawing which shows the structure of the oil tank in 1st Embodiment Sectional drawing which shows the structure of the oil tank in 2nd Embodiment Sectional drawing which shows the structure of the oil tank in 3rd Embodiment Sectional drawing which shows the structure of the oil tank in 4th Embodiment Diagram showing the shape of the oil tank used in the durability test Diagram showing the results of the durability test

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Forklift, 2 ... Oil tank, 10 ... Tank main body, 20 ... Cylindrical member, 24 ... Cylinder vent, 26 ... Bottom cover, 30 ... Air blizzard, 40 ... Suction pipe, 50 ... Return pipe, 60 ... Oil inlet, 70 ... Level gauge, 80 ... Wall member, 82 ... Wall vent, 86 ... Bottom lid.

Claims (5)

A tank body for storing hydraulic fluid;
A hollow cylindrical member extending from the outside to the inside of the tank body;
An air breather attached to the end of the tubular member located outside the tank body, and for circulating air from the inside of the tank body to the outside via the tubular member;
An oil tank consisting of
The cylindrical member is a portion located inside the tank main body, and in a portion higher than the hydraulic fluid level that becomes the hydraulic fluid level in a state where the hydraulic fluid is stored in the tank main body, A cylinder vent hole extending from the outer peripheral part to the inner peripheral part of the cylindrical member is formed,
Inside the tank body, a wall member is provided so as to surround a portion of the outer peripheral portion of the cylindrical member that is higher than the hydraulic fluid surface,
Further, the wall member is formed with a wall vent from the front surface portion to the back surface portion of the wall member ,
The oil tank according to claim 1, wherein the cylindrical member has a length such that an end portion on the side located inside the tank body reaches a position lower than the hydraulic fluid level . The total area of the cylindrical air holes formed in the cylindrical member is configured to be equal to or larger than the area of a hollow portion in a cross section orthogonal to the length direction of the cylindrical member. Item 2. The oil tank according to Item 1 . Wherein the tubular member, according to claim 1, characterized in that it is formed of at least two or more of the tubular vent, or, an oil tank according to claim 2. The oil tank according to any one of claims 1 to 3, wherein at least two or more wall vents are formed in the wall member. A moving body having an operating mechanism that operates with hydraulic fluid stored in an oil tank,
The said oil tank is comprised with the oil tank in any one of Claim 1 to 4. The mobile body characterized by the above-mentioned.