Work vehicles

Abstract

To provide a work vehicle allowing the degree of freedom for installation of a hydraulic pump to be enhanced through reduction of damage or malfunction caused by idling of the hydraulic pump even in a configuration in which the hydraulic pump is placed at a position higher than a liquid level of hydraulic oil in a hydraulic oil tank.SOLUTION: A work vehicle comprises: a hydraulic oil tank storing hydraulic oil; a hydraulic pump connected to the hydraulic tank through a first hydraulic hose; and hydraulic equipment connected to the hydraulic pump through a second hydraulic hose. The hydraulic pump is positioned at a position higher than a liquid level of the hydraulic oil in the hydraulic oil tank. At least a part of the second hydraulic hose is positioned at a position lower than the liquid level.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, in work vehicles such as hydraulic excavators, attempts have been made to compact the piping structure around the hydraulic pump to miniaturize the work vehicle (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in a configuration where the hydraulic pump is arranged at a position higher than the liquid level of the hydraulic oil in the hydraulic oil tank, when the engine is stopped, that is, when the drive of the hydraulic pump is stopped, depending on the arrangement method of the hydraulic hoses, the hydraulic oil in the hydraulic pump may flow to the hydraulic oil tank side through the hydraulic hoses, and as a result, the inside of the hydraulic pump may become empty. In this case, when the engine is then rotated to start the drive of the hydraulic pump, the hydraulic pump is initially driven with an idle rotation (this phenomenon is also called "air biting"). Such an idle rotation of the hydraulic pump causes damage or failure of the hydraulic pump. Therefore, conventionally, the hydraulic pump has to be arranged at a position lower than the liquid level of the hydraulic oil in the hydraulic oil tank, and there are restrictions on the arrangement position of the hydraulic pump.

[0005] The present invention was made to solve the above-mentioned problems, and its objective is to provide a work vehicle that can reduce damage or failure due to the hydraulic pump running dry, even when the hydraulic pump is positioned higher than the liquid level of the hydraulic fluid in the hydraulic fluid tank, by devising the routing of the hydraulic hose, thereby increasing the degree of freedom in the installation of the hydraulic pump. [Means for solving the problem]

[0006] A work vehicle according to one aspect of the present invention comprises a hydraulic oil tank for storing hydraulic oil, a hydraulic pump connected to the hydraulic oil tank via a first hydraulic hose, and hydraulic equipment connected to the hydraulic pump via a second hydraulic hose, wherein the hydraulic pump is positioned higher than the liquid level of the hydraulic oil in the hydraulic oil tank, and at least a portion of the second hydraulic hose is positioned lower than the liquid level. [Effects of the Invention]

[0007] According to the above configuration, even if the hydraulic pump is positioned higher than the fluid level of the hydraulic fluid in the hydraulic fluid tank, damage or failure due to the hydraulic pump running idle can be reduced, thereby increasing the flexibility of hydraulic pump installation. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view showing a schematic configuration of a hydraulic excavator, which is an example of a work vehicle according to one embodiment of the present invention. [Figure 2] This is a block diagram schematically showing the configuration of the hydraulic system of the above-mentioned hydraulic excavator. [Figure 3] This is a perspective view from the upper left rear showing the internal configuration of the engine room of the upper rotating body of the hydraulic excavator described above. [Figure 4] This is a perspective view from the left rear showing the internal layout of the engine room. [Figure 5] This is a rear view showing the internal configuration of the engine room. [Figure 6]This is a floor plan showing the internal layout of the engine room. [Figure 7] This is a perspective view showing other internal components of the engine room described above. [Figure 8] This is a rear view showing the other components inside the engine room. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings.

[0010] [1. Work Vehicles] Figure 1 is a side view showing the schematic configuration of a hydraulic excavator 1, which is an example of a work vehicle in this embodiment. The hydraulic excavator 1 comprises a lower traveling body 2, a work implement 3, and an upper rotating body 4.

[0011] Here, directions are defined as follows. First, the direction in which the lower traveling body 2 moves in a straight line is defined as the front-rear direction, with one side being defined as "front" and the other as "rear". In Figure 1, as an example, the blade 23 side is shown as "front" relative to the traveling motor 22. Also, the lateral direction perpendicular to the front-rear direction is defined as the left-right direction. In this case, the left side is defined as "left" and the right side as viewed from the perspective of the operator (driver) seated in the driver's seat 41a. Furthermore, the direction of gravity perpendicular to the front-rear and left-right directions is defined as the up-down direction, with the upstream side of the direction of gravity being defined as "up" and the downstream side as "down". In the drawings, the forward direction is indicated by the symbol "F", the rear by "B", the right by "R", the left by "L", the upper by "U", and the lower by "D" as needed.

[0012] The lower travel body 2 comprises a pair of left and right crawlers 21 and a pair of left and right travel motors 22. Each travel motor 22 is a hydraulic motor. The left and right travel motors 22 drive the left and right crawlers 21 respectively, allowing the hydraulic excavator 1 to move forward and backward. The lower travel body 2 is equipped with a blade 23 for leveling work and a blade cylinder 23a. The blade cylinder 23a is a hydraulic cylinder that rotates the blade 23 in the vertical direction.

[0013] The work machine 3 comprises a boom 31, an arm 32, and a bucket 33. By independently driving the boom 31, arm 32, and bucket 33, excavation work such as soil and sand can be performed.

[0014] The boom 31 is rotated by the boom cylinder 31a. The boom cylinder 31a is supported at its base end on the front of the upper slewing body 4 and is movable in an extendable and retractable manner. The arm 32 is rotated by the arm cylinder 32a. The arm cylinder 32a is supported at its base end on the boom 31 and is movable in an extendable and retractable manner. The bucket 33 is rotated by the bucket cylinder 33a. The bucket cylinder 33a is supported at its base end on the arm 32 and is movable in an extendable and retractable manner. The boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a are composed of hydraulic cylinders.

[0015] The upper rotating body 4 houses a control unit 41, a turntable 42, a rotation motor 43, and an engine room 44. The upper rotating body 4 rotates via rotation bearings (not shown) driven by the rotation motor 43, which is a hydraulic motor.

[0016] The control unit 41 is located on top of the turntable 42. The control unit 41 has a driver's seat 41a. The control unit 41b is located around the driver's seat 41a. The control unit 41b consists of control levers, switches, buttons, pedals, etc. When the operator sits in the driver's seat 41a and operates the control unit 41b, the hydraulic actuator AC (see Figure 2) is driven. This allows the lower travel body 2 to travel and switch its travel speed, perform leveling work with the blade 23, perform excavation work with the work machine 3, rotate the upper turntable 4, and so on.

[0017] The engine room 44 is located at the rear of the upper rotating body 4. Inside the engine room 44 are the engines 51 that supply power to various parts. The power from the engines 51 is supplied to the pilot pump PP and the main pump MP shown in Figure 2 via gears and shafts. Note that the pilot pump PP and the main pump MP are examples of hydraulic pumps HP.

[0018] 〔2. Configuration of Hydraulic System〕 FIG. 2 is a block diagram schematically showing the configuration of the hydraulic system of the hydraulic excavator 1. The hydraulic excavator 1 of the present embodiment includes a hydraulic oil tank TC, a main pump MP, a hydraulic actuator AC, a pilot pump PP, a control valve CV, a remote control valve RV, and a solenoid valve SV. Note that the solenoid valve SV is an example of a hydraulic device HE.

[0019] The hydraulic oil tank TC stores hydraulic oil. The hydraulic oil stored in the hydraulic oil tank TC is supplied to the hydraulic actuator AC via the control valve CV by driving the main pump MP. Thereby, the hydraulic actuator AC is driven. The hydraulic actuator AC is composed of the traveling motor 22, swing motor 43, boom cylinder 31a, arm cylinder 32a, bucket cylinder 33a, blade cylinder 23a, etc. described above.

[0020] The pilot pump PP discharges pilot oil that serves as an input command to the control valve CV. The control valve CV is a direction switching valve that controls the flow direction and flow rate of the hydraulic oil (pressure oil) supplied from the main pump MP to the hydraulic actuator AC. The control valve CV is provided corresponding to each hydraulic actuator AC (hydraulic motor, hydraulic cylinder). The control valve CV may be arranged in front of the driver's seat 41a where the operator sits, or may be arranged below the driver's seat 41a.

[0021] The remote control valve RV is provided to switch the direction and pressure of the pilot oil supplied from the pilot pump PP to the control valve CV. The remote control valve RV constitutes, for example, an operation lever of the operation unit 41b, and generates a pilot secondary pressure by reducing the pressure (pilot pressure) of the pilot oil supplied from the pilot pump PP according to the operation direction and operation amount of the operation lever.

[0022] The solenoid valve SV is located in the oil passage between the pilot pump PP and the remote control valve RV, and switches the supply of pilot oil (hydraulic oil) from the pilot pump PP to the remote control valve RV on and off. In other words, the solenoid valve SV is an on / off valve that can switch the communication of the above oil passage on and off. Here, "on" refers to a state in which communication of a predetermined amount or more of hydraulic oil is permitted. Conversely, "off" refers to a state in which communication of a predetermined amount or more of hydraulic oil is not permitted. In other words, "on" communication includes cases other than a complete communication state. Similarly, "off" communication includes cases other than a complete disconnection state.

[0023] The solenoid valve SV is switched on or off according to the on / off status of the cutoff switch (not shown). The cutoff switch is a detection unit that detects the rotational position of the cutoff lever, which constitutes the operating unit 41b.

[0024] [3. Regarding the routing of hydraulic hoses] Figure 3 is a perspective view from the upper left rear showing the internal configuration of the engine room 44 of the upper rotating body 4. Figure 4 is a perspective view from the left rear showing the internal configuration of the engine room 44. Figure 5 is a rear view showing the internal configuration of the engine room 44. Figure 6 is a top view showing the internal configuration of the engine room 44. As shown in these figures, the pilot pump PP, which is the hydraulic pump HP, is connected to the hydraulic oil tank TC via the first hydraulic hose H1. The solenoid valve SV mentioned above is connected to the pilot pump PP via the second hydraulic hose H2.

[0025] In this embodiment, as shown in Figures 4 and 5, the pilot pump PP is positioned higher than the hydraulic fluid level LS in the hydraulic fluid tank TC. A portion of the second hydraulic hose H2 is positioned lower than the fluid level LS.

[0026] In this configuration, even when the engine 51 is stopped and the pilot pump PP is also stopped, the pilot pump PP can remain filled with hydraulic fluid. This is because the hydraulic fluid remains in the portion of the second hydraulic hose H2 below the fluid level LS, preventing the hydraulic fluid from flowing through the second hydraulic hose H2 from the solenoid valve SV to the hydraulic fluid tank TC via the pilot pump PP. A more detailed explanation of this point is as follows.

[0027] For example, if any part of the piping path is open to the atmosphere, the oil level in the piping will drop to a height that balances the pressure on the hydraulic oil tank TC side (=atmospheric pressure) (=liquid level LS in the hydraulic oil tank TC) due to atmospheric pressure (i.e., hydraulic oil will flow). In actual hydraulic piping, this "opening to the atmosphere" can occur, for example, in the drain piping of the solenoid valve SV, which is a hydraulic equipment HE. Even if air enters the second hydraulic hose H2 from the hydraulic equipment HE side due to the above-mentioned opening to the atmosphere when the engine 51 is stopped, a portion of the second hydraulic hose H2 is positioned lower than the liquid level LS, so the oil level of the hydraulic oil in the second hydraulic hose H2 will not drop below the liquid level LS of the hydraulic oil stored in the hydraulic oil tank TC. Therefore, hydraulic oil will not flow from the solenoid valve SV side to the hydraulic oil tank TC via the pilot pump PP through the second hydraulic hose H2, and the state in which the pilot pump PP is filled with hydraulic oil can be maintained.

[0028] This reduces the possibility of the pilot pump PP initially running idle (air entrapment) when it is started by the engine 51. As a result, damage or failure of the pilot pump PP due to idle can be reduced. Therefore, the constraint of placing the pilot pump PP below the hydraulic fluid level LS in the hydraulic fluid tank TC to reduce damage or failure of the pilot pump PP due to idle can be eliminated. As a result, the degree of freedom in the installation (layout) of the pilot pump PP can be increased.

[0029] In this embodiment, as shown in Figures 3 to 5, the pilot pump PP and the second hydraulic hose H2 are connected via a connector CN. The connector CN is formed, for example, in an L-shape, and its entirety is located above the liquid level LS. This connector CN may also extend downward from the pilot pump PP to a position below the liquid level LS and then bend horizontally. Furthermore, the solenoid valve SV, which is a hydraulic device HE, may be located below the liquid level LS.

[0030] In this configuration, the entire second hydraulic hose H2 is positioned below the liquid level LS. Even with this configuration, when the pilot pump PP is stopped, hydraulic fluid remains in the second hydraulic hose H2, which is below the liquid level LS. As a result, hydraulic fluid does not flow from the solenoid valve SV to the hydraulic fluid tank TC via the pilot pump PP through the second hydraulic hose H2. This allows the pilot pump PP to remain filled with hydraulic fluid. Therefore, damage or failure due to the pilot pump PP running dry can be reduced.

[0031] From the above, it can be said that in a configuration where the pilot pump PP, which acts as the hydraulic pump HP, is positioned higher than the liquid level LS, it is sufficient that at least a portion of the second hydraulic hose H2 is positioned lower than the liquid level LS.

[0032] The second hydraulic hose H2 described above has an intermediate section H2a, a first connection section H2b, and a second connection section H2c. The intermediate section H2a is located below the liquid level LS in the hydraulic oil tank TC. The first connection section H2b is located between the intermediate section H2a and the solenoid valve SV, which is a hydraulic device HE, and is located at a height above the liquid level LS. The second connection section H2c is located between the intermediate section H2a and the pilot pump PP, which is a hydraulic pump HP, and is located at a height above the liquid level LS. Therefore, of the intermediate section H2a, the first connection section H2b, and the second connection section H2c, the intermediate section H2a is located at the lowest position.

[0033] By configuring the second hydraulic hose H2 in this way, it becomes possible to achieve a layout in which the hydraulic equipment HE (solenoid valve SV) and the hydraulic pump HP (pilot pump PP) are positioned higher than the liquid level LS.

[0034] In a layout where the hydraulic equipment HE (solenoid valve SV) is positioned higher than the liquid level LS, when the hydraulic pump HP (pilot pump PP) is stopped, air may enter the second hydraulic hose H2 (especially the first connection point H2b) from the hydraulic equipment HE side due to the aforementioned venting to the atmosphere. However, even in this case, due to the above-described arrangement of the second hydraulic hose H2, the oil level of the hydraulic fluid in the second hydraulic hose H2 will not fall below the liquid level LS of the hydraulic fluid stored in the hydraulic fluid tank TC. Therefore, even when the hydraulic pump HP is stopped, it is possible to maintain a state in which hydraulic fluid remains in the part of the second hydraulic hose H2 that is lower than the liquid level LS (especially the middle section H2a), thereby maintaining a state in which the hydraulic pump HP is filled with hydraulic fluid and preventing air from leaking into the hydraulic pump HP.

[0035] The second hydraulic hose H2 is routed along the outer surface TC-S of the hydraulic oil tank TC. The outer surface TC-S refers to the outer surface of the hydraulic oil tank TC, that is, the surface of the hydraulic oil tank TC opposite to the inner surface that comes into contact with the hydraulic oil.

[0036] In this case, the maintainability of the second hydraulic hose H2 can be improved. In other words, if the maintenance worker knows the location of the hydraulic oil tank TC, it will be easy to find the second hydraulic hose H2, making maintenance such as replacing the second hydraulic hose H2 easier.

[0037] The hydraulic fluid tank TC described above has a level gauge LG. The level gauge LG is a viewing window for looking into the hydraulic fluid in the hydraulic fluid tank TC. By looking into the hydraulic fluid tank TC through the level gauge LG, the maintenance worker can check the amount of hydraulic fluid in the hydraulic fluid tank TC, i.e., the height of the hydraulic fluid level LS. In this embodiment, a portion of the second hydraulic hose H2 (for example, the intermediate portion H2a) is positioned lower than the level gauge LG.

[0038] In the hydraulic fluid tank TC, the hydraulic fluid level LS is usually located near the height of the level gauge LG. Therefore, by positioning a portion of the second hydraulic hose H2 (for example, the middle section H2a) below the level gauge LG, it becomes easier to route the second hydraulic hose H2 such that a portion of the second hydraulic hose H2 is positioned below the fluid level LS. In other words, the desired routing of the second hydraulic hose H2 can be easily achieved using the level gauge LG as a guide.

[0039] Furthermore, the entirety of the second hydraulic hose H2 may be positioned lower than the level gauge LG. In this case, it becomes easier to route the second hydraulic hose H2 such that the entirety of the second hydraulic hose H2 is positioned lower than the liquid level LS. Therefore, in this embodiment, it is sufficient that at least a portion of the second hydraulic hose H2 is positioned lower than the level gauge LG.

[0040] As shown in Figures 3 and 4, the hydraulic oil tank TC has a retaining part HU. The retaining part HU holds the second hydraulic hose H2. Such a retaining part HU is fixed to the outer surface TC-S of the hydraulic oil tank TC and consists of a hook for hooking the second hydraulic hose H2. Alternatively, the retaining part HU may consist of a clamping member that holds the second hydraulic hose H2.

[0041] In this embodiment, the hydraulic oil tank TC is provided with three retaining parts HU, but the number of retaining parts HU is not particularly limited and may be one, two, or four or more. For convenience, the retaining parts HU are not shown in Figures 5 and 6.

[0042] The holding portion HU holds the second hydraulic hose H2 in place of the hydraulic oil tank TC (especially the outer surface TC-S), allowing the second hydraulic hose H2 to be compactly routed around the hydraulic oil tank TC. In other words, it prevents the second hydraulic hose H2 from spreading out and being routed in the space surrounding the hydraulic oil tank TC. It also makes it easier to maintain a state where at least a portion of the second hydraulic hose H2 is located below the liquid level LS.

[0043] As shown in Figures 3 to 6, the pilot pump PP, which is the hydraulic pump HP, is positioned on one side of the hydraulic oil tank TC in the width direction. Here, the width direction of the hydraulic oil tank TC refers to the same direction as the left-right direction of the hydraulic excavator 1, for example. For example, the pilot pump PP is positioned on the right side (inside the machine body) of the hydraulic oil tank TC.

[0044] In this positional relationship between the hydraulic pump HP and the hydraulic fluid tank TC, the first hydraulic hose H1, which connects to the hydraulic fluid tank TC, can be routed from the hydraulic fluid tank TC to one side in the width direction (for example, the right side) and connected to the hydraulic pump HP. This allows for a compact routing of the first hydraulic hose H1.

[0045] Furthermore, in this embodiment, the hydraulic equipment HE, like the pilot pump PP, is positioned on one side of the hydraulic oil tank TC in the width direction of the hydraulic oil tank. Specifically, the solenoid valve SV, which is part of the hydraulic equipment HE, is positioned to the right of the hydraulic oil tank TC.

[0046] In a configuration where the hydraulic pump HP (pilot pump PP) and hydraulic equipment HE (solenoid valve SV) are located on the same side (e.g., the right side) of the hydraulic oil tank TC, the same-side arrangement space relative to the hydraulic oil tank TC is shared by the hydraulic pump HP and the hydraulic equipment HE, enabling efficient arrangement of the hydraulic pump HP and the hydraulic equipment HE. This allows for a reduction in the width (left-right direction) of the hydraulic excavator 1 compared to a configuration where the hydraulic pump HP and the hydraulic equipment HE are located on opposite sides of the hydraulic oil tank TC. As a result, miniaturization of the hydraulic excavator 1 becomes easier.

[0047] In contrast, the aforementioned retaining part HU is positioned on the other side in the width direction of the hydraulic oil tank TC. Specifically, the retaining part HU is positioned on the left side (outside the machine body) of the hydraulic oil tank TC. As a result, the second hydraulic hose H2 is positioned on the outside of the hydraulic excavator 1 (on the bonnet side, not the internal engine side). Consequently, maintenance of the second hydraulic hose H2 becomes easier.

[0048] As a result of the second hydraulic hose H2 being held by the retaining part HU positioned in this manner, the second hydraulic hose H2 is routed from the hydraulic pump HP (pilot pump PP) to the hydraulic equipment HE (solenoid valve SV) from one side (e.g., the right side) to the other side (e.g., the left side) in the width direction relative to the hydraulic oil tank TC, and then routed from the other side back to the first side. This increases the distance between the hydraulic pump HP and the hydraulic equipment HE. Therefore, even if the hydraulic pump HP vibrates when the engine 51 is driven, the vibration of the hydraulic pump HP is less likely to be transmitted to the hydraulic equipment HE via the second hydraulic hose H2. As a result, the hydraulic equipment HE is less likely to vibrate, and the risk of failure of the hydraulic equipment HE is reduced. Thus, the durability and reliability of the hydraulic equipment HE can be improved.

[0049] As shown in Figures 3 and 4, the holding portion HU includes a lower holding portion HU-1 positioned lower than the level gauge LG. The lower holding portion HU-1 holds the second hydraulic hose H2, ensuring that at least a portion of the second hydraulic hose H2 is positioned lower than the level gauge LG. In other words, ensuring that at least a portion of the second hydraulic hose H2 is positioned lower than the liquid level LS.

[0050] As shown in Figures 3 and 5, the engine 51 of the hydraulic excavator 1 is located on one side (for example, the right side) of the width direction of the hydraulic oil tank TC. Therefore, in the width direction (left-right direction) of the hydraulic oil tank TC, the hydraulic pump HP and the engine 51 are located on the same side relative to the hydraulic oil tank TC. However, the hydraulic pump HP is located at a different position (offset position) from the power shaft AX of the engine 51. The power shaft AX is the rotation axis (central axis) of the crankshaft of the engine 51.

[0051] Specifically, the pilot pump PP, which functions as the hydraulic pump HP, is positioned diagonally upward and rearward with respect to the power shaft AX. The input shaft of the pilot pump PP is connected to the power shaft AX of the engine 51 via a power transmission mechanism such as gears and shafts. As a result, the driving force of the engine 51 is transmitted to the pilot pump PP via the power transmission mechanism.

[0052] As described above, in a configuration where the power shaft AX of the engine 51 and the hydraulic pump HP are offset from each other on one side in the width direction of the hydraulic oil tank TC, the total width dimension of the hydraulic oil tank TC, engine 51, and hydraulic pump HP can be kept smaller compared to a configuration where the engine 51 and hydraulic pump HP are arranged side by side along the power shaft AX. This makes it possible to keep the width (width in the left-right direction) of the hydraulic excavator 1, which corresponds to the width direction, smaller, and makes it easier to miniaturize the hydraulic excavator 1.

[0053] Furthermore, as shown in Figures 3 and 6, the hydraulic pump HP (e.g., pilot pump PP) is located behind the engine 51. In this configuration, maintenance personnel can easily access the hydraulic pump HP by opening the bonnet (not shown) which forms the rear side wall of the engine compartment 44. In other words, access to the hydraulic pump HP is not obstructed by the engine 51. Therefore, maintenance personnel can easily perform maintenance on the hydraulic pump HP.

[0054] As shown in Figures 3 to 6, the hydraulic excavator 1 is equipped with a fan F. The fan F is provided to cool the radiator RA shown in Figure 5. The fan F rotates when the driving force output from the power shaft AX of the engine 51 is transmitted via pulleys, belts, etc.

[0055] Within the engine room 44, the radiator RA is located above the hydraulic oil tank TC. The fan F is positioned between the radiator RA and the engine 51. Therefore, the fan F is positioned on the hydraulic oil tank TC side relative to the engine 51.

[0056] With this arrangement of fan F, the fan F can cool both the radiator RA and the hydraulic oil tank TC. In other words, the fan F, originally installed for cooling the radiator RA, can also be used to cool the hydraulic oil tank TC. Therefore, there is no need to install a dedicated fan for cooling the hydraulic oil tank TC, and the configuration inside the engine room 44 can be simplified.

[0057] As shown in Figures 3 and 6, the hydraulic equipment HE (e.g., solenoid valve SV) is positioned in front of the engine 51. With this arrangement of the hydraulic equipment HE, the hydraulic equipment HE, engine 51, and hydraulic pump HP can be positioned in the front-to-back direction. This makes it easier to keep the width of the hydraulic excavator 1 smaller compared to a configuration in which the hydraulic equipment HE, engine 51, and hydraulic pump HP are positioned, for example, in the left-to-right direction.

[0058] [4. Other routing options for hydraulic hoses] Figure 7 is a perspective view from the upper left rear showing other configurations inside the engine room 44 of the upper rotating body 4. Figure 8 is a rear view showing the above-mentioned other configurations. The second hydraulic hose H2 connecting the solenoid valve SV (see Figure 6, etc.) and the pilot pump PP may have multiple bends. More specifically, the second hydraulic hose H2 may have a first bend 101 and a second bend 102 as multiple bends.

[0059] The first bent portion 101 has a shape that bends back and forth in a first direction (for example, vertically). Specifically, the first bent portion 101 has a first hose portion 101a (see Figure 8), a second hose portion 101b, and a third hose portion 101c.

[0060] The second hose section 101b is positioned lower than the liquid level LS in the hydraulic oil tank TC. The first hose section 101a connects the pilot pump PP (hydraulic pump HP) to one end (right end) of the second hose section 101b and is positioned at a height above the liquid level LS. The third hose section 101c connects the other end (left end) of the second hose section 101b to the second bend section 102 (particularly the fourth hose section 102a described later) and is positioned at a height above the liquid level LS. In other words, the first hose section 101a extends downward from the top (the side connected to the pilot pump PP) and connects to the second hose section 101b. The third hose section 101c extends upward from the bottom (the side connected to the second hose section 101b) and connects to the second bend section 102. This constitutes the first bend section 101, which bends back and forth in the vertical direction. Furthermore, the first hose section 101a and the third hose section 101c may or may not be parallel to each other (one may be inclined relative to the other). Also, the first hose section 101a and the third hose section 101c may or may be the same length.

[0061] The second bent section 102 is connected to the pilot pump PP on the opposite side of the machine in the left-right direction from the first bent section 101. In other words, the first bent section 101 and the second bent section 102 are located in different positions (they do not overlap except at the connection point).

[0062] The second bent portion 102 has a shape that bends back and forth in a second direction (for example, left-right direction) different from the first direction. Specifically, as shown in Figure 7, the second bent portion 102 has a fourth hose portion 102a, a fifth hose portion 102b, and a sixth hose portion 102c.

[0063] The fifth hose section 102b is the portion that extends from rear to front above the hydraulic oil tank TC. The fourth hose section 102a extends to the left from the side that connects to the first bend 101 (particularly the third hose section 101c) and connects to the rear end of the fifth hose section 102b. The fourth hose section 102a contacts the lower part of the radiator RA and is pressed downward. This stabilizes the routing of the second bend 102. The sixth hose section 102c is connected to the front end of the fifth hose section 102b, extends to the right from the front end, and connects to the solenoid valve SV. This constitutes the second bend 102 that bends back and forth in the left-right direction. Note that the fourth hose section 102a and the sixth hose section 102c may or may not be parallel to each other (one may be inclined relative to the other). Furthermore, the fourth hose section 102a and the sixth hose section 102c may be the same length or may be of different lengths.

[0064] The second bend 102 (fourth hose section 102a, fifth hose section 102b, sixth hose section 102c) is positioned higher than the liquid level LS. Therefore, in the configuration of the second hydraulic hose H2 shown in Figures 7 and 8, the second hose section 101b of the first bend 101 constitutes an intermediate section H2a that is positioned lower than the liquid level LS. Furthermore, the third hose section 101c of the first bend 101 and the second bend 102 constitute a first connection section H2b that is positioned between the intermediate section H2a and the hydraulic equipment HE (solenoid valve SV) and is positioned at a height above the liquid level LS. In addition, the first hose section 101a of the first bend 101 constitutes a second connection section H2c that is positioned between the intermediate section H2a and the hydraulic pump HP (pilot pump PP) and is positioned at a height above the liquid level LS.

[0065] The hydraulic excavator 1 further comprises a support section 110. The support section 110 is attached to any frame or stay within the engine room 44 and supports the second hydraulic hose H2. For example, the support section 110 supports the third hose section 101c of the first bend 101. This stabilizes the routing of the second hydraulic hose H2. The support section 110 may support only the first bend 101, or it may support only the second bend 102, as shown in Figures 7 and 8. Alternatively, the support section 110 may be provided corresponding to the first bend 101 and the second bend 102, respectively, to support the first bend 101 and the second bend 102 at different locations. In any case, from the viewpoint of stabilizing the routing of the second hydraulic hose H2, it is desirable that the support section 110 supports at least one of the multiple bends (first bend 101, second bend 102).

[0066] Furthermore, in order to facilitate the routing of the second hydraulic hose H2, which is positioned at least partially below the liquid level LS, and to stably support the second hydraulic hose H2 with a small number of support parts 110, it is desirable to reduce the load caused by bending in the second hydraulic hose H2. To this end, a configuration in which the bending points of the second hydraulic hose H2 are distributed is preferable to a configuration in which the bending points are concentrated. In this regard, as shown in Figures 7 and 8, it is desirable that the first bending point 101 and the second bending point 102 be positioned at different locations.

[0067] Furthermore, if the first bend 101 and the second bend 102 are located in different positions, it becomes possible to arrange the support portion 110 to support only the first bend 101 of the second hydraulic hose H2, as shown in Figures 7 and 8. In this arrangement of the support portion 110, the support portion 110 is located on the right side of the hydraulic oil tank TC (on the inside side of the engine room 44), so even if the bonnet located on the left side of the hydraulic oil tank TC is removed, the support portion 110 will not be visible from the hydraulic oil tank TC side (because it will be hidden by the hydraulic oil tank TC). In this respect as well, the configuration in which the first bend 101 and the second bend 102 are located in different positions is desirable.

[0068] In a configuration where the support portion 110 supports the third hose portion 101c of the first bend portion 101, if the position of the support portion 110 is too low, the portion downstream from the support point of the third hose portion 101c (especially the fourth hose portion 102a of the second bend portion 102) becomes unstable. As a result, the fourth hose portion 102a becomes prone to movement. On the other hand, if the position of the support portion 110 is too high, a large bending stress is applied to the connection point between the third hose portion 101c and the fourth hose portion 102a. As a result, it becomes difficult to guide the fourth hose portion 102a from the support point to the space between the hydraulic oil tank TC and the radiator RA. For this reason, it is desirable that the support portion 110 supports the intermediate position in the first direction (vertical direction) of the third hose portion 101c (the portion above the liquid level LS).

[0069] In the above explanation, the first direction was defined as the vertical direction and the second direction as the horizontal direction (width direction). However, the first direction may also be the horizontal direction, and the second direction may also be the vertical direction. Furthermore, either the first or second direction may be the front-back direction.

[0070] Furthermore, although the above description has focused on the case where the second hydraulic hose H2 has multiple bends, specifically a first bend 101 and a second bend 102, the second hydraulic hose H2 may have three or more bends. In this case, at least two of the three or more bends must be in different directions for reciprocating bending.

[0071] [5. Other] In this embodiment, a pilot pump PP was used as an example to describe the hydraulic pump HP, which is positioned higher than the hydraulic fluid level LS in the hydraulic fluid tank TC. However, the same considerations apply to the main pump MP. That is, in a configuration where the main pump MP is positioned higher than the hydraulic fluid level LS in the hydraulic fluid tank TC and connected to hydraulic equipment HE (e.g., control valve CV) via a second hydraulic hose H2, damage or failure due to the main pump MP running idle can be reduced by positioning at least a portion of the second hydraulic hose H2 below the fluid level LS. Therefore, the constraint that the main pump MP must be positioned below the fluid level LS can be eliminated, increasing the flexibility of the main pump MP's installation.

[0072] In this embodiment, a solenoid valve SV was used as an example of hydraulic equipment HE, but any equipment that controls hydraulic pressure is acceptable, and it is not limited to a solenoid valve SV. For example, the control valve CV described above can also constitute hydraulic equipment HE.

[0073] The hydraulic excavator 1 may also be configured to drive the hydraulic pump HP using an electric motor instead of an engine 51.

[0074] In this embodiment, the support portion 110 (see Figure 7) is fixed to a stay or the like in the engine room 44, rather than to the hydraulic oil tank TC, and supports the second hydraulic hose H2. In this respect, it is distinguished in terms of wording from the retaining portion HU (see Figure 4) which is fixed to the hydraulic oil tank TC. However, both the support portion 110 and the retaining portion HU have the common function of "supporting" the second hydraulic hose H2. Furthermore, one end of the support portion 110 may be fixed to the hydraulic oil tank TC, and the other end may extend to the right of the machine body to support the second hydraulic hose H2. Therefore, it is possible to replace the support portion 110 in Figure 7 with a retaining portion HU fixed to the hydraulic oil tank TC, and conversely, it is also possible to replace the retaining portion HU in Figure 4 with a support portion fixed to a stay or the like.

[0075] [6. Addendum] The hydraulic excavator 1 described in this embodiment can also be described as the work vehicle shown in the following appendix.

[0076] The work vehicles mentioned in Appendix (1) are: A hydraulic oil tank for storing hydraulic fluid, A hydraulic pump connected to the hydraulic fluid tank via a first hydraulic hose, The system includes hydraulic equipment connected to the hydraulic pump via a second hydraulic hose, The hydraulic pump is positioned higher than the liquid level of the hydraulic fluid in the hydraulic fluid tank. At least a portion of the second hydraulic hose is positioned below the liquid level.

[0077] The work vehicles in Appendix (2) are the work vehicles described in Appendix (1), The second hydraulic hose is An intermediate section positioned at a lower level than the aforementioned liquid surface, A first connecting portion is positioned between the intermediate portion and the hydraulic equipment and is positioned at a height above the liquid level, It has a second connecting portion which is positioned between the intermediate portion and the hydraulic pump and is positioned at a height above the liquid level.

[0078] The work vehicles in Appendix (3) are the work vehicles described in Appendix (1) or (2), The second hydraulic hose has multiple bends, The aforementioned multiple bent portions are, A first bent section that bends back and forth in the first direction, It has a second bent portion that bends back and forth in a second direction different from the first direction, The first bent portion and the second bent portion are provided at different positions.

[0079] The work vehicles in Appendix (4) are the work vehicles described in Appendix (3), The system further includes a support for the second hydraulic hose, The support portion supports at least one of the plurality of bent portions.

[0080] The work vehicle in Appendix (5) is one of the work vehicles described in any of Appendix (1) to (4), The hydraulic equipment is positioned higher than the liquid level.

[0081] The work vehicle in Appendix (6) is one of the work vehicles described in any of Appendix (1) to (5), The second hydraulic hose is routed along the outer surface of the hydraulic fluid tank.

[0082] The work vehicle in Appendix (7) is one of the work vehicles described in any of Appendix (1) to (6), The hydraulic fluid tank has a level gauge (which serves as a viewing window inside the tank), At least a portion of the second hydraulic hose is positioned lower than the level gauge.

[0083] The work vehicles in Appendix (8) are the work vehicles described in Appendix (7), The hydraulic fluid tank has a retaining portion for holding the second hydraulic hose.

[0084] The work vehicles in Appendix (9) are the work vehicles described in Appendix (8), The hydraulic pump is positioned on one side of the hydraulic fluid tank in the width direction relative to the hydraulic fluid tank.

[0085] The work vehicles in Appendix (10) are the work vehicles described in Appendix (9), The hydraulic equipment is positioned on one side in the width direction relative to the hydraulic fluid tank.

[0086] The work vehicles in Appendix (11) are the work vehicles described in Appendix (9) or (10), The holding portion is positioned on the other side in the width direction of the hydraulic fluid tank.

[0087] The work vehicle in Appendix (12) is one of the work vehicles described in any of Appendix (8) to (11), The holding portion includes a lower-position holding portion that is positioned lower than the level gauge.

[0088] The work vehicle in Appendix (13) is one of the work vehicles described in any of Appendix (1) to (12), The engine is further located on one side in the width direction of the hydraulic fluid tank, The hydraulic pump is positioned at a location different from the power shaft of the engine.

[0089] The work vehicles in Appendix (14) are the work vehicles described in Appendix (13), The hydraulic pump is located behind the engine.

[0090] The work vehicles in Appendix (15) are the work vehicles described in Appendix (13) or (14), The engine further comprises a fan positioned on the hydraulic fluid tank side.

[0091] The work vehicle in Appendix (16) is one of the work vehicles described in any of Appendix (13) to (15), The hydraulic equipment is positioned in front of the engine.

[0092] Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it can be expanded or modified without departing from the spirit of the invention. [Industrial applicability]

[0093] This invention can be used, for example, in work vehicles such as construction machinery and agricultural machinery. [Explanation of symbols]

[0094] 1. Hydraulic excavator (work vehicle) 51 Engine 101 1st bending part 102 Second bending part 110 Support part AX power shaft F Fan H1 1st Hydraulic Hose H2 No. 2 Hydraulic Hose H2a middle part H2b First Connection H2c Second Connection Section HE hydraulic equipment HP Hydraulic Pump HU holding part HU-1 Low holding part LG Level Gauge LS liquid level MP Main Pump (Hydraulic Pump) PP Pilot Pump (Hydraulic Pump) SV Solenoid Valve (Hydraulic Equipment) TC hydraulic fluid tank TC-S external surface

Claims

1. A hydraulic oil tank for storing hydraulic fluid, A hydraulic pump connected to the hydraulic fluid tank via a first hydraulic hose, The system includes hydraulic equipment connected to the hydraulic pump via a second hydraulic hose, The hydraulic pump is positioned higher than the liquid level of the hydraulic fluid in the hydraulic fluid tank. A work vehicle in which a portion of the second hydraulic hose is positioned below the liquid level, and the remaining portion of the second hydraulic hose is positioned at a height above the liquid level.

2. A hydraulic oil tank for storing hydraulic oil, A hydraulic pump connected to the hydraulic fluid tank via a first hydraulic hose, The system includes hydraulic equipment connected to the hydraulic pump via a second hydraulic hose, The hydraulic pump is positioned higher than the liquid level of the hydraulic fluid in the hydraulic fluid tank. At least a portion of the second hydraulic hose is positioned below the liquid level. The second hydraulic hose is, An intermediate section positioned at a lower level than the aforementioned liquid surface, A first connecting portion is positioned between the intermediate portion and the hydraulic equipment and is positioned at a height above the liquid level, A work vehicle having a second connecting portion positioned between the intermediate portion and the hydraulic pump, and positioned at a height above the liquid level.

3. A hydraulic oil tank for storing hydraulic oil, A hydraulic pump connected to the hydraulic fluid tank via a first hydraulic hose, The system includes hydraulic equipment connected to the hydraulic pump via a second hydraulic hose, The hydraulic pump is positioned higher than the liquid level of the hydraulic fluid in the hydraulic fluid tank. At least a portion of the second hydraulic hose is positioned below the liquid level. The second hydraulic hose has a plurality of bends, The aforementioned multiple bent portions are, A first bent portion that bends back and forth in a first direction, It has a second bent portion that bends back and forth in a second direction different from the first direction, A work vehicle in which the first bend and the second bend are located at different positions.

4. The system further includes a support for the second hydraulic hose, The work vehicle according to claim 3, wherein the support portion supports at least one of the plurality of bent portions.

5. The work vehicle according to any one of claims 1 to 3, wherein the hydraulic equipment is positioned higher than the liquid level.

6. The work vehicle according to any one of claims 1 to 3, wherein the second hydraulic hose is routed along the outer surface of the hydraulic fluid tank.

7. The hydraulic fluid tank has a level gauge, A work vehicle according to any one of claims 1 to 3, wherein a portion of the second hydraulic hose is positioned lower than the level gauge.

8. The work vehicle according to claim 7, wherein the hydraulic fluid tank has a holding portion for holding the second hydraulic hose.

9. The work vehicle according to claim 8, wherein the hydraulic pump is positioned on one side of the hydraulic fluid tank in the width direction relative to the hydraulic fluid tank.

10. The work vehicle according to claim 9, wherein the hydraulic equipment is arranged on one side in the width direction relative to the hydraulic oil tank.

11. The work vehicle according to claim 9, wherein the holding portion is located on the other side in the width direction of the hydraulic fluid tank.

12. The work vehicle according to claim 8, wherein the holding portion includes a low-position holding portion positioned lower than the level gauge.

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