Work machinery

Abstract

To provide a work machine allowing a height of a cooling device including a radiator and a storage tank in an airtight type to be low.SOLUTION: A hydraulic shovel as a work machine includes: a radiator 51; a fan 63 opposite to the radiator 51; and a storage tank 71 storing cooling water from the radiator 51 in a non-contact state with atmospheric air and aligned with the radiator 51 in a rotation shaft direction of the fan 63. The radiator 51 has a radiator upper surface 55. The storage tank 71 has a tank upper surface 73 and a tank lower surface 74. The tank upper surface 73 is arranged at a position higher than the radiator upper surface 55. The tank lower surface 74 is arranged at a position lower than the radiator upper surface 55. In a top view, a width of the storage tank 71 in a specific direction orthogonal to the rotation shaft of the fan 63 and parallel to a horizontal direction is greater than a width of the radiator 51 in a specific direction orthogonal to the rotation shaft of the fan 63 and parallel to the horizontal direction.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to work machines. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2017-185931 (Patent Document 1) discloses a cooling system for construction machinery that includes an intercooler, a radiator and oil cooler arranged below the intercooler and having a width shorter than that of the intercooler, and a pressurized, sealed reservoir tank arranged to the side of the intercooler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-185931 Summary of the Invention [Problem to be solved by the invention]

[0004] A known work machine is equipped with a cooling system that includes a radiator and a storage tank that stores the cooling water from the radiator to accommodate volume changes due to thermal expansion of the cooling water. Types of storage tanks include sealed types that store the cooling water without contacting the atmosphere.

[0005] When a sealed storage tank is used, the radiator does not have a radiator cap. When assembling the cooling system, the coolant is introduced into the radiator through a filler port provided in the storage tank. To allow the coolant to be introduced into the radiator, the storage tank must be located higher than the radiator. However, simply placing the storage tank above the radiator, as in the cooling system disclosed in Patent Document 1, increases the height of the cooling system.

[0006] Therefore, an object of the present disclosure is to provide a work machine in which the height of a cooling device including a radiator and a sealed storage tank can be kept low. [Means for solving the problem]

[0007] A work machine according to one aspect of the present disclosure includes a radiator, a fan, and a storage tank. The radiator is configured to cool coolant. The fan is disposed opposite the radiator. The storage tank stores the coolant from the radiator without contacting the atmosphere. The storage tank is disposed alongside the radiator in the direction of the rotational axis of the fan. The radiator has a radiator upper surface. The storage tank has a tank upper surface and a tank lower surface. The tank upper surface is disposed at a higher position than the radiator upper surface. The tank lower surface is disposed at a lower position than the radiator upper surface. In a top view, the width of the storage tank in a predetermined direction perpendicular to the rotational axis of the fan and parallel to the horizontal direction is greater than the width of the radiator in a predetermined direction perpendicular to the rotational axis of the fan and parallel to the horizontal direction.

[0008] A work machine according to another aspect of the present disclosure includes a radiator, a fan, and a storage tank. The radiator is configured to cool coolant. The fan is disposed opposite the radiator. The storage tank stores the coolant from the radiator without contacting the atmosphere. The storage tank is provided alongside the radiator in the direction of the rotational axis of the fan. The radiator has a radiator upper surface. The storage tank has a tank upper surface and a tank lower surface. The tank upper surface is disposed at a position higher than the radiator upper surface. The tank lower surface is disposed at a position lower than the radiator upper surface. The storage tank further has a first tank side surface and a second tank side surface. The second tank side surface faces the first tank side surface. In a top view, the first tank side surface is disposed in an area on one side of the rotational axis of the fan, and the second tank side surface is disposed in an area on the other side of the rotational axis of the fan. [Effects of the Invention]

[0009] According to the present disclosure, a work machine can be provided in which the height of a cooling device including a radiator and a sealed storage tank can be kept low. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view showing a hydraulic excavator in a first embodiment. [Figure 2] FIG. 2 is a top view showing the inside of the engine compartment in FIG. [Figure 3] FIG. 3 is a circuit diagram showing a cooling system for the engine in FIG. 2. [Figure 4] FIG. 3 is a perspective view showing a cooling device in FIG. 2. [Figure 5] FIG. 3 is a perspective view showing a cooling device and a fan in FIG. 2. [Figure 6] 6 is a cross-sectional view showing the cooling device and the fan as seen from the direction of the arrows on line VI-VI in FIG. 4. [Figure 7] 7 is a cross-sectional view showing the characteristic structure of the radiator, storage tank, and shroud in the area surrounded by the two-dot chain line VII in FIG. 6. FIG. [Figure 8] 4 is a diagram showing the water levels (initial state) of the coolant in the radiator and the storage tank. FIG. [Figure 9] 4 is a diagram showing the water level (expansion state) of the cooling water in the radiator and the storage tank. FIG. [Figure 10] FIG. 5 is a top view showing the storage tank, the shroud, and the fan in FIG. 4. [Figure 11] FIG. 6 is a perspective view showing the storage tank in FIG. 5. [Figure 12] FIG. 5 is a top view showing the storage tank and the shroud in FIG. 4. [Figure 13] 13 is a cross-sectional view showing the storage tank as viewed from the direction of the arrows on line XIII-XIII in FIG. 12. [Figure 14] 4 is a diagram showing the height relationship between the lower surface of the upper tank of the radiator and the lower surface of the storage tank. FIG. [Figure 15] 4 is a diagram showing the height relationship between the lower surface of the upper tank of the radiator and the lower surface of the storage tank. FIG. [Figure 16] FIG. 10 is a perspective view showing a cooling device for a hydraulic excavator in a second embodiment. [Figure 17] FIG. 11 is a top view showing a cooling device and a fan of a hydraulic excavator in a third embodiment. [Figure 18] FIG. 10 is a perspective view showing a cooling device for a hydraulic excavator in a fourth embodiment. [Figure 19] FIG. 20 is a circuit diagram showing an engine cooling system to which the cooling device in FIG. 18 is applied. [Figure 20] 19 is a cross-sectional view showing the cooling device as seen in the direction of the arrows on the line XX-XX in FIG. 18. [Figure 21] FIG. 19 is a cross-sectional view showing the tank cap in FIG. [Figure 22] 19 is a top view showing the storage tank and tank cap in FIG. 18, and piping routed between the storage tank and the tank cap. FIG. [Figure 23] 19 is another top view showing the storage tank and tank cap in FIG. 18, and the piping routed between the storage tank and the tank cap. FIG. [Figure 24] 23 is a top view showing a modified example of the first bending portion in FIG. 22. FIG. [Figure 25] FIG. 19 is a perspective view showing a modified example of the cooling device of the hydraulic excavator in FIG. [Figure 26] 26 is a cross-sectional view showing the storage tank and the tank cap as seen in the direction of the arrows on line XXVI-XXVI in FIG. 25. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are designated by the same reference numerals.

[0012] (Embodiment 1) Fig. 1 is a side view showing a hydraulic excavator in embodiment 1. As shown in Fig. 1, a hydraulic excavator 10 has a main body 21 and a work machine 12. The main body 21 has a traveling device 22 and a revolving body 25.

[0013] The traveling device 22 has a pair of tracks 23 and a traveling motor 24. The hydraulic excavator 10 is capable of traveling by rotation of the tracks 23. The traveling motor 24 is provided as a drive source for the traveling device 22. The traveling motor 24 is a hydraulic motor that is operated by hydraulic pressure. Note that the traveling device 22 may have wheels (tires).

[0014] The rotating body 25 is provided on the traveling device 22 and is supported by the traveling device 22. The rotating body 25 can rotate relative to the traveling device 22 around a rotation axis that extends in the vertical direction. The rotating body 25 has an operator's cab 26. The operator's cab 26 is provided with an operator's seat in which an operator sits. The operator can operate the hydraulic excavator 10 from the operator's cab 26.

[0015] In this specification, the fore-and-aft direction refers to the fore-and-aft direction of the operator seated in the driver's seat inside the cab 26. The direction in front of the operator seated in the driver's seat is the front, and the direction behind the operator seated in the driver's seat is the rear. The left-and-right direction refers to the left-and-right direction of the operator seated in the driver's seat. The right side of the operator seated in the driver's seat when facing forward is the right side, and the left side of the operator seated in the driver's seat when facing forward is the left side. The up-and-down direction refers to the direction perpendicular to a plane that includes the fore-and-aft direction and the left-and-right direction. The side with the ground is the down side, and the side with the sky is the up side.

[0016] The revolving unit 25 has an engine room 31 and a counterweight 28. The engine room 31 is provided in front of the counterweight 28. The engine room 31 is provided behind the operator's cab 26. The engine room 31 accommodates an engine 33, a cooling device 40, and the like, which will be described later.

[0017] The work implement 12 is provided in front of the rotating structure 25. The work implement 12 is supported by the rotating structure 25. The work implement 12 has a boom 14, an arm 16, a bucket 18, and hydraulic cylinders 15, 17, and 19. The boom 14 is rotatably connected to the rotating structure 25. The arm 16 is rotatably connected to the boom 14. The bucket 18 is rotatably connected to the arm 16. The hydraulic cylinder 15 drives the boom 14. The hydraulic cylinder 17 drives the arm 16. The hydraulic cylinder 19 drives the bucket 18.

[0018] Fig. 2 is a top view showing the inside of the engine compartment in Fig. 1. As shown in Fig. 2, the hydraulic excavator 10 has a hydraulic pump 36, a flywheel housing 35, an engine 33, and a cooling device 40.

[0019] The hydraulic pump 36, the flywheel housing 35, the engine 33, and the cooling device 40 are housed in the engine room 31. The hydraulic pump 36, the flywheel housing 35, the engine 33, and the cooling device 40 are lined up in the left-right direction in the engine room 31. The hydraulic pump 36, the flywheel housing 35, the engine 33, and the cooling device 40 are lined up in the listed order from left to right.

[0020] The order of the hydraulic pump 36, the flywheel housing 35, the engine 33, and the cooling device 40 may be reversed. In this case, the hydraulic pump 36 is disposed at the right end, and the cooling device 40 is disposed at the left end.

[0021] The engine 33 has a crankshaft 34. The crankshaft 34 is a shaft that converts the reciprocating motion of the pistons in the engine 33 into rotational motion. The engine 33 is provided so that the crankshaft 34 extends in the left-right direction. The hydraulic pump 36 is attached to the engine 33 via a flywheel housing 35. The hydraulic pump 36 is driven by receiving the rotational motion output from the engine 33. The hydraulic pump 36 supplies hydraulic oil to various actuators such as the hydraulic cylinders 15, 17, and 19 described above. The cooling device 40 is disposed on the opposite side of the hydraulic pump 36 in the left-right direction, with the engine 33 in between.

[0022] The cooling device 40 has an oil cooler 41, a radiator 51, a shroud 62, and a storage tank 71. The cooling device 40 is configured by a cooling unit in which the oil cooler 41, the radiator 51, the shroud 62, and the storage tank 71 are integrated.

[0023] The oil cooler 41 is configured to cool the hydraulic oil supplied from the hydraulic pump 36 to the various actuators. The radiator 51 is configured to cool the cooling water for the engine 33. The oil cooler 41 and the radiator 51 are arranged side by side in the front-to-rear direction.

[0024] The hydraulic excavator 10 has a fan 63. The fan 63 is configured to supply cooling air to the oil cooler 41 and the radiator 51. The fan 63 rotates about a rotation shaft 101 by receiving rotational motion output from the engine 33. The rotation shaft 101 is an imaginary straight line representing the center of rotation of the fan 63, and extends parallel to the crankshaft 34. The rotation shaft 101 extends in the left-right direction.

[0025] The shroud 62 is a case body that covers the outer periphery of the fan 63. The fan 63 and the shroud 62 are disposed opposite the oil cooler 41 and the radiator 51 in the axial direction of the rotation shaft 101 of the fan 63. The fan 63 and the shroud 62 are disposed opposite the oil cooler 41 and the radiator 51 in the left-right direction. The fan 63 and the shroud 62 are disposed between the oil cooler 41 and the radiator 51 and the engine 33 in the left-right direction.

[0026] The storage tank 71 is configured to store the coolant from the radiator 51 in accordance with a change in volume caused by a change in the temperature of the coolant. The storage tank 71 is provided above the shroud 62. The structure and arrangement of the storage tank 71 will be described in detail later.

[0027] 1 and 2, the hydraulic excavator 10 has an exterior cover 29. The exterior cover 29 is part of a cover body that defines an engine compartment 31.

[0028] The exterior cover 29 is disposed opposite the oil cooler 41 and the radiator 51 in the left-right direction. A ventilation space 38 is provided between the exterior cover 29 and the oil cooler 41 and the radiator 51. The exterior cover 29 is provided with a ventilation hole 30. The ventilation hole 30 is a through-hole that connects the ventilation space 38 with the space outside the engine compartment 31.

[0029] As the fan 63 rotates, air outside the engine compartment 31 flows into the ventilation space 38 through the vent 30. The air passes from the ventilation space 38 through the oil cooler 41 and the radiator 51 and is drawn toward the shroud 62 in which the fan 63 is disposed.

[0030] FIG. 3 is a circuit diagram showing the cooling system of the engine in FIG. 2. As shown in FIG. 3, storage tank 71 forms storage space 79. Storage tank 71 is a sealed type that stores cooling water in storage space 79 without contacting the atmosphere. An air layer is provided above the cooling water stored in storage space 79. Sealed types include a "completely sealed type" in which the air layer inside storage tank 71 is completely isolated from the atmosphere outside storage tank 71, and a "pressurized sealed type" in which air is released from the air layer inside storage tank 71 when the internal pressure of storage tank 71 is high; here, the "pressurized sealed type" will be described as an example.

[0031] The storage tank 71 is provided with a tank cap 72. The tank cap 72 is provided to close a water inlet provided in the storage tank 71. The tank cap 72 has a pressure release function. The tank cap 72 opens when the internal pressure of the storage tank 71 exceeds a preset upper limit value, thereby releasing the pressurized air inside the storage tank 71. The tank cap 72 does not open within the normal range in which the internal pressure of the storage tank 71 changes.

[0032] The hydraulic excavator 10 has a pipe member 42 and a pipe member 43, a pipe member 45 and a pipe member 47, and a pipe member 44.

[0033] The pipe member 42 is connected at both ends to the engine 33 and a radiator 51 (an upper tank portion 53 in FIG. 6 described later). The pipe member 43 is connected at both ends to the radiator 51 (a lower tank portion 54 in FIG. 6 described later) and the engine 33. The engine 33, the pipe member 42, the radiator 51, and the pipe member 43 form a cooling water circulation path 50.

[0034] The cooling water cools the engine 33. The cooling water, whose temperature has increased by cooling the engine 33, passes through pipe member 42 and is supplied to radiator 51. The cooling water is cooled by exchanging heat with outside air in radiator 51. The cooling water, whose temperature has decreased, passes through pipe member 43 and is supplied to the engine 33 again.

[0035] Both ends of the pipe member 45 are connected to the radiator 51 (upper tank portion 53 in FIG. 6 described later) and the storage tank 71. Both ends of the pipe member 47 are connected to the storage tank 71 and the pipe member 43, and the cooling water in the storage tank 71 and the cooling water that has passed through the radiator 51 join together and are supplied to the pump 46.

[0036] When the temperature of the coolant circulating through the circulation path 50 rises, the volume of the coolant increases. At this time, the coolant overflowing from the radiator 51 is supplied to the storage tank 71 through the pipe member 45. This increases the amount of coolant stored in the storage tank 71. When the temperature of the coolant circulating through the circulation path 50 drops, the volume of the coolant decreases. At this time, the coolant stored in the storage tank 71 passes through the pipe member 47 and is returned to the pipe line of the pipe member 43 in the circulation path 50.

[0037] The pipe member 44 is connected at both ends to the engine 33 and the radiator 51 (an upper tank portion 53 in FIG. 6 described later). The pipe member 44 is provided as a conduit for bleeding air from the engine 33 to the radiator 51. The pipe member 45 functions as a conduit for guiding the overflowed cooling water to the storage tank 71, as well as a conduit for bleeding air from the radiator 51 to the storage tank 71.

[0038] Fig. 4 is a perspective view showing the cooling device in Fig. 2. Fig. 4 shows the cooling device 40 as seen from the ventilation space 38 side in Fig. 2. Fig. 5 is a perspective view showing the cooling device and fan in Fig. 2. Fig. 5 shows the cooling device 40 and fan 63 as seen from the engine 33 side in Fig. 2. Fig. 6 is a cross-sectional view showing the cooling device and fan as seen from the direction of the arrows on line VI-VI in Fig. 4.

[0039] 4 to 6, radiator 51 has a flat plate-like appearance. The thickness direction of radiator 51 is parallel to the axial direction of rotation shaft 101 of fan 63. When viewed from the axial direction of rotation shaft 101 of fan 63, radiator 51 has a rectangular shape with its longitudinal direction parallel to the vertical direction and its lateral direction parallel to the horizontal direction.

[0040] The oil cooler 41 has a flat plate-like appearance similar to the radiator 51. The oil cooler 41 is provided so that the thickness direction of the oil cooler 41 is parallel to the thickness direction of the radiator 51 and is aligned horizontally with the oil cooler 41. The oil cooler 41 is provided alongside the radiator 51 in the horizontal direction perpendicular to the rotation axis 101 of the fan 63. When viewed from the axial direction of the rotation axis 101 of the fan 63, the oil cooler 41 and the radiator 51 have a rectangular shape with an aspect ratio closer to a square than the oil cooler 41 alone and closer to a square than the radiator 51 alone.

[0041] Fig. 7 is a cross-sectional view showing the characteristic structures of the radiator, storage tank, and shroud in the area surrounded by two-dot chain line VII in Fig. 6. As shown in Figs. 3, 6, and 7, radiator 51 has a core portion 52, an upper tank portion 53, and a lower tank portion 54.

[0042] The upper tank portion 53 is provided above the core portion 52. The lower tank portion is provided below the core portion 52. The core portion 52 is provided between the upper tank portion 53 and the lower tank portion in the up-down direction.

[0043] The upper tank portion 53 forms a collecting space 59 where the coolant collects. The lower tank portion 54 forms a collecting space 60 where the coolant collects. The collecting spaces 59 and 60 have rectangular cross sections and extend horizontally, perpendicular to the rotation axis 101 of the fan 63.

[0044] In the core portion 52, the coolant flows while exchanging heat with the outside air. The core portion 52 has a plurality of tubes 57 and a plurality of fins 58. The plurality of fins 58 are arranged vertically at intervals from one another. The plurality of tubes 57 extend between the upper tank portion 53 and the lower tank portion 54, penetrating the plurality of fins 58. The plurality of tubes 57 communicate with a collecting space 59 in the upper tank portion 53. The plurality of tubes 57 communicate with a collecting space 60 in the lower tank portion 54.

[0045] High-temperature coolant supplied from the engine 33 to the radiator 51 through the pipe member 42 first collects in a collecting space 59 in the upper tank portion 53. The coolant travels from the collecting space 59 through a plurality of tubes 57 in the core portion 52 and collects in a collecting space 60 in the lower tank portion 54. While flowing through the plurality of tubes 57, the coolant exchanges heat with outside air through a plurality of fins 58. The coolant, whose temperature has been reduced by the heat exchange with the outside air, is returned from the collecting space 60 through the pipe member 43 to the engine 33.

[0046] The radiator in the present disclosure is not limited to the downflow type in which the cooling water flows upward, but may be a side flow type in which the cooling water flows horizontally.

[0047] As shown in Figures 4 to 6, the fan 63 has a shaft portion 66 and a plurality of blade portions 67. The shaft portion 66 extends axially along the rotation axis 101 of the fan 63. Rotational motion from the engine 33 is input to the shaft portion 66. The blade portions 67 extend from the shaft portion 66 radially outward from the rotation axis 101. The plurality of blade portions 67 are provided at intervals from one another in the circumferential direction of the rotation axis 101.

[0048] The shroud 62 has a base 65 and a cylindrical portion 64. The base 65 has a rectangular parallelepiped shape and is provided so as to surround the periphery of the shroud 62. The base 65 has a circular opening on the side facing the engine 33 in the axial direction of the rotation shaft 101 of the fan 63, and has a rectangular opening on the side facing the ventilation space 38 (oil cooler 41 and radiator 51) in the axial direction of the rotation shaft 101 of the fan 63. The cylindrical portion 64 has a cylindrical shape centered on the rotation shaft 101 of the fan 63. The cylindrical portion 64 protrudes cylindrically from the periphery of the circular opening in the base 65 in a direction approaching the engine 33.

[0049] The base 65 has a top plate 68. The top plate 68 is made of a horizontally extending plate and forms the top plate of the base 65. When viewed from above, the top plate 68 has a rectangular shape with its short side oriented in the axial direction of the rotation shaft 101 of the fan 63 and its long side oriented in a direction perpendicular to the rotation shaft 101 of the fan 63. The top plate 68 has an extension 86. The extension 86 has an eave shape that extends toward the engine 33 in the axial direction of the rotation shaft 101 of the fan 63. The extension 86 is disposed above the cylindrical portion 64.

[0050] The storage tank 71 has a rectangular parallelepiped shape. The storage space 79 has a rectangular cross section and extends in a horizontal direction perpendicular to the rotation axis 101 of the fan 63.

[0051] The storage tank 71 is provided alongside the radiator 51. The storage tank 71 is provided alongside the radiator 51 in the axial direction of the rotation shaft 101 of the fan 63. The storage tank 71 is provided alongside the upper tank portion 53 of the radiator 51 in the axial direction of the rotation shaft 101 of the fan 63.

[0052] The storage tank 71 is provided above the shroud 62. The storage tank 71 is placed on the top plate portion 68. The storage tank 71 is fastened to the top plate portion 68. The storage tank 71 is provided between the radiator 51 and the engine 33 in the axial direction of the rotation shaft 101 of the fan 63. The storage tank 71 is provided downstream of the radiator 51 in the direction of the air flow created by the rotation of the fan 63.

[0053] The hydraulic excavator 10 has a support member 81. The support member 81 is made up of a frame body that has a rectangular shape when viewed in the axial direction of the rotation shaft 101 of the fan 63.

[0054] The radiator 51, oil cooler 41, shroud 62, and storage tank 71 are supported together by a support member 81. The radiator 51 and oil cooler 41 are disposed inside the support member 81. The shroud 62 is fixed to the support member 81 from the engine 33 side in the axial direction of the rotation shaft 101 of the fan 63. The storage tank 71 is supported by the support member 81 via the shroud 62.

[0055] 4 to 7, radiator 51 has radiator upper surface 55. Radiator upper surface 55 forms the upper surface of radiator 51 at the top of radiator 51. When viewed from above, radiator upper surface 55 has a rectangular shape in which the axial direction of rotation shaft 101 of fan 63 is the short side direction and the direction perpendicular to rotation shaft 101 of fan 63 is the long side direction.

[0056] The upper tank portion 53 has the above-mentioned radiator upper surface 55 and an upper tank lower surface 56. The radiator upper surface 55 is disposed above the collecting space 59. The radiator upper surface 55 defines the collecting space 59. The upper tank lower surface 56 is disposed below the collecting space 59. The upper tank lower surface 56 defines the collecting space 59. The multiple tubes 57 open to the upper tank lower surface 56. The radiator upper surface 55 and the upper tank lower surface 56 face each other in the vertical direction, with the collecting space 59 in between.

[0057] The storage tank 71 has a tank upper surface 73, a tank lower surface 74, a first tank side surface 75, a second tank side surface 76, a third tank side surface 77, and a fourth tank side surface 78. The tank upper surface 73, the tank lower surface 74, the first tank side surface 75, the second tank side surface 76, the third tank side surface 77, and the fourth tank side surface 78 constitute the six surfaces of the storage tank 71, which has a rectangular parallelepiped shape.

[0058] Tank upper surface 73 is disposed above storage space 79. Tank upper surface 73 defines storage space 79. Tank lower surface 74 is disposed below storage space 79. Tank lower surface 74 defines storage space 79. Tank upper surface 73 and tank lower surface 74 face each other in the vertical direction, with storage space 79 sandwiched between them.

[0059] Each of the tank upper surface 73 and the tank lower surface 74 has a rectangular shape in which the axial direction of the rotation shaft 101 of the fan 63 is the short side direction and the direction perpendicular to the rotation shaft 101 of the fan 63 is the long side direction when viewed from above. The tank upper surface 73 has a recess 80. The recess 80 has a concave shape that is recessed downward when viewed from outside the storage space 79. The tank cap 72 is provided in the recess 80. The tank lower surface 74 is superimposed on the top plate portion 68 from above.

[0060] The first tank side surface 75, the second tank side surface 76, the third tank side surface 77, and the fourth tank side surface 78 are arranged on the sides of the storage space 79. The first tank side surface 75, the second tank side surface 76, the third tank side surface 77, and the fourth tank side surface 78 surround and partition the storage space 79 from all four sides in the horizontal direction. The first tank side surface 75 and the second tank side surface 76 face each other in the horizontal direction perpendicular to the rotation axis 101 of the fan 63, with the storage space 79 between them.

[0061] The third tank side surface 77 and the fourth tank side surface 78 face each other in the axial direction of the rotation shaft 101 of the fan 63, with a storage space 79 sandwiched between them. The third tank side surface 77 faces the radiator 51 in the axial direction of the rotation shaft 101 of the fan 63. The fourth tank side surface 78 faces the engine 33 in the axial direction of the rotation shaft 101 of the fan 63. A step 82 is attached to the fourth tank side surface 78 to provide footholds for workers when performing maintenance on the hydraulic excavator 10.

[0062] 7, the tank upper surface 73 is disposed at a position higher than the radiator upper surface 55. The tank lower surface 74 is disposed at a position lower than the radiator upper surface 55. The radiator upper surface 55 is disposed between the tank upper surface 73 and the tank lower surface 74 in the vertical direction.

[0063] 8 is a diagram showing the water levels (initial state) of the cooling water in the radiator and the storage tank. The initial state means a state in which the cooling system of the engine 33 is not operating and the cooling water is at normal temperature.

[0064] 7 and 8, in a cooling system using a sealed storage tank 71, when assembling cooling device 40, tank cap 72 is removed from storage tank 71 and coolant is introduced into radiator 51 through the opened water inlet. At this time, because tank upper surface 73 is positioned higher than radiator upper surface 55, coolant can be introduced into radiator 51 with air layer 122 formed in storage tank 71.

[0065] On the other hand, a configuration in which storage tank 71 is simply stacked on top of radiator 51 increases the height of cooling device 40. In contrast, tank lower surface 74 is located at a position lower than radiator upper surface 55, so the height of cooling device 40 can be kept low.

[0066] In addition, when the radiator in the present disclosure is a side flow type, the radiator has a core portion and a pair of tank portions provided on both sides of the core portion in the horizontal direction. In this case, the upper surface of the radiator is generally the upper surfaces (upper end surfaces) of the pair of tank portions.

[0067] FIG. 9 is a diagram showing the water levels (expansion state) of the coolant in the radiator and the storage tank.

[0068] 8 and 9, when the temperature of the coolant rises and the coolant expands, the coolant overflows from radiator 51, causing the coolant level in storage space 79 of storage tank 71 to rise. At this time, because storage space 79 is an enclosed space isolated from the atmosphere, it is necessary to ensure an air layer 122 within storage space 79 to allow the coolant level to rise. Therefore, storage tank 71 is required to have a large volume of storage space 79 to an extent that allows air layer 122 to be ensured, depending on the range of temperature change (volume change) of the coolant.

[0069] In contrast, in radiator 51 in the initial state shown in Fig. 8, the water level of the coolant in upper tank portion 53 (collection space 59) is set so that air layer 121 is provided above the coolant. With this configuration, in radiator 51 in the expanded state shown in Fig. 9, part of the expanded coolant occupies air layer 121, and the remaining part of the expanded coolant moves to storage space 79, so that the volume of storage space 79 can be reduced by the amount of air layer 121. This makes it possible to reduce the size of storage tank 71, and ultimately, the height of cooling device 40 can be further reduced.

[0070] Fig. 10 is a top view showing the storage tank, shroud, and fan in Fig. 4. As shown in Figs. 4 and 10, in the top view, the width B1 of the storage tank 71 in a direction perpendicular to the rotation axis 101 of the fan 63 is larger than the width B2 (Fig. 4) of the radiator 51 in a direction perpendicular to the rotation axis 101 of the fan 63. The width B1 of the storage tank 71 is the length between the first tank side surface 75 and the second tank side surface 76. The width B2 of the radiator 51 is the length of each of the upper tank portion 53 and the lower tank portion 54 in the direction perpendicular to the rotation axis 101 of the fan 63.

[0071] With this configuration, the capacity of the storage space 79 in the storage tank 71 can be increased.

[0072] 10 , in a top view, an area 110 is defined on one side of the rotation shaft 101 of the fan 63, and an area 120 is defined on the other side of the rotation shaft 101 of the fan 63. The first tank side surface 75 is located in the area 110. The second tank side surface 76 is located in the area 120.

[0073] According to this configuration, the storage tank 71 is provided widely in the areas 110 and 120 on both sides of the rotation shaft 101 of the fan 63, so that the capacity of the storage space 79 in the storage tank 71 can be increased.

[0074] In a top view, the distance L between the rotation axis 101 of the fan 63 and the first tank side surface 75 is greater than the radius R of the fan 63. The radius R of the fan 63 is the length between the rotation axis 101 of the fan 63 and the tip of the blade portion 67 that is located radially outermost among the blade portions 67.

[0075] According to this configuration, by providing the storage tank 71 with a width exceeding the maximum outer diameter of the fan 63, the capacity of the storage space 79 in the storage tank 71 can be increased.

[0076] In addition, the storage tank 71 may be configured so that both the distance between the rotation axis 101 of the fan 63 and the first tank side surface 75 and the distance between the rotation axis 101 of the fan 63 and the second tank side surface 76 are greater than the radius R of the fan 63, or may be configured so that only the distance between the rotation axis 101 of the fan 63 and the second tank side surface 76 is greater than the radius R of the fan 63.

[0077] Fig. 11 is a perspective view showing the storage tank in Fig. 5. Fig. 11 shows the storage tank 71 as seen from the tank bottom surface 74 side. Fig. 12 is a top view showing the storage tank and shroud in Fig. 4. Fig. 13 is a cross-sectional view showing the storage tank as seen from the direction of the arrows on line XIII-XIII in Fig. 12.

[0078] 11 to 13, the top panel 68 (extension 86) has a cutout 87. The cutout 87 has a shape in which an end edge of the extension 86 on the side facing the engine 33 is cut away in the axial direction of the rotation shaft 101 of the fan 63, in a direction approaching the ventilation space 38. The cutout 87 is provided across a predetermined width on both sides of the rotation shaft 101 of the fan 63 in top view.

[0079] The tank lower surface 74 has a recess 91. The recess 91 has a concave shape that is recessed downward when viewed from the inside of the storage space 79. The recess 91 is disposed in the cutout portion 87. The pipe member 47 is connected to the tank lower surface 74. The pipe member 47 is connected to the recess 91.

[0080] 12, the pipe member 47 is connected to the center of the tank lower surface 74 in a direction perpendicular to the rotation axis 101 of the fan 63. The length between the connection port of the pipe member 47 on the tank lower surface 74 and the first tank side surface 75 in the horizontal direction perpendicular to the rotation axis 101 of the fan 63 is equal to the length between the connection port of the pipe member 47 on the tank lower surface 74 and the second tank side surface 76 in the horizontal direction perpendicular to the rotation axis 101 of the fan 63.

[0081] With this configuration, even if the water surface of the cooling water in the storage space 79 tilts due to a change in the attitude of the hydraulic excavator 10, it is possible to prevent the connection port of the pipe member 47 on the tank underside 74 from being exposed from the cooling water. This makes it possible to prevent air from entering the cooling water circulation path 50.

[0082] 6 and 7, the shroud 62 has an opposing surface 69. The opposing surface 69 is provided alongside the third tank side surface 77 in the vertical direction. The opposing surface 69 faces the radiator 51 across a gap in the axial direction of the rotation shaft 101 of the fan 63. The opposing surface 69 is a side surface of the base 65 on the side facing the ventilation space 38 (oil cooler 41 and radiator 51) in the axial direction of the rotation shaft 101 of the fan 63.

[0083] The third tank side surface 77 of the storage tank 71 is arranged at a position aligned with the opposing surface 69 in the axial direction of the rotation shaft 101 of the fan 63. The third tank side surface 77 may be arranged at a position farther from the radiator 51 than the opposing surface 69 in the axial direction of the rotation shaft 101 of the fan 63. The third tank side surface 77 is arranged so as not to protrude further toward the ventilation space 38 (radiator 51) than the opposing surface 69 in the axial direction of the rotation shaft 101 of the fan 63.

[0084] According to this configuration, when performing maintenance on the core portion 52 of the radiator 51 through the gaps between the radiator 51 and the storage tank 71 and the shroud 62, the core portion 52 can be accessed without being obstructed by the storage tank 71. This improves the ease of maintenance of the radiator 51.

[0085] 14 and 15 are diagrams showing the height relationship between the lower surface of the upper tank of the radiator and the lower surface of the storage tank.

[0086] 14, when the tank lower surface 74 is positioned higher than the upper tank lower surface 56, the diameter of the fan 63 can be set so that the height of the upper end of the range through which the blades 67 pass is higher than the height of the upper end of the core portion 52. This makes it easier for the airflow generated by the rotation of the fan 63 to reach the entire core portion 52, thereby improving the cooling efficiency of the coolant in the radiator 51.

[0087] As shown in FIG. 15, when the tank lower surface 74 is positioned at the same height as the upper tank lower surface 56 or at a position lower than the upper tank lower surface 56, the capacity of the storage tank 71 (storage space 79) can be increased.

[0088] In this configuration, the shroud 62 may have a guide portion 92 for circulating the airflow generated by the rotation of the fan 63 throughout the entire core portion 52. As an example, the guide portion 92 has a cylindrical portion 93 and a tapered portion 94. The cylindrical portion 93 is provided below the storage tank 71. The cylindrical portion 93 is provided so as to cover the fan 63. The cylindrical portion 93 has a cylindrical shape extending along the axial direction of the rotation shaft 101 of the fan 63. The tapered portion 94 extends from the end of the cylindrical portion 93 in the axial direction of the rotation shaft 101 of the fan 63 in a direction approaching the ventilation space 38 (radiator 51) while increasing the opening area.

[0089] The configuration and effects of the hydraulic excavator 10 according to the first embodiment described above will now be summarized.

[0090] The hydraulic excavator 10 as a work machine includes a radiator 51 and a storage tank 71. The radiator 51 is configured to cool the engine coolant. The storage tank 71 stores the coolant from the radiator 51 without contacting the atmosphere. The storage tank 71 is provided alongside the radiator 51. The radiator 51 has a radiator upper surface 55. The storage tank 71 has a tank upper surface 73 and a tank lower surface 74. The tank upper surface 73 is located at a higher position than the radiator upper surface 55. The tank lower surface 74 is located at a lower position than the radiator upper surface 55.

[0091] According to this configuration, tank upper surface 73 is positioned higher than radiator upper surface 55, making it possible to introduce cooling water into radiator 51 through storage tank 71. Furthermore, tank lower surface 74 is positioned lower than radiator upper surface 55, making it possible to keep the height of cooling device 40, including radiator 51 and storage tank 71, low.

[0092] The hydraulic excavator 10 further includes a fan 63. The fan 63 is disposed opposite the radiator 51. The storage tank 71 is provided alongside the radiator 51 in the axial direction of the rotation shaft 101 of the fan 63.

[0093] With this configuration, the radiator 51, the storage tank 71, and the fan 63 can be arranged compactly.

[0094] The storage tank 71 further has a first tank side surface 75 and a second tank side surface 76. The second tank side surface 76 faces the first tank side surface 75. In a top view, the first tank side surface 75 is located in an area 110 on one side of the rotation shaft of the fan 63, and the second tank side surface 76 is located in an area 120 on the other side of the rotation shaft of the fan 63.

[0095] With this configuration, the capacity of the storage space 79 of the storage tank 71 can be increased.

[0096] Furthermore, the distance between the rotation axis 101 of the fan 63 and at least one of the first tank side surface 75 and the second tank side surface 76 is greater than the radius of the fan 63 when viewed from above.

[0097] With this configuration, the capacity of the storage space 79 of the storage tank 71 can be further increased.

[0098] In addition, the width of the storage tank 71 in a direction perpendicular to the rotation axis 101 of the fan 63 is greater than the width of the radiator 51 in a direction perpendicular to the rotation axis 101 of the fan 63 when viewed from above.

[0099] With this configuration, the capacity of the storage space 79 of the storage tank 71 can be increased.

[0100] The hydraulic excavator 10 further includes a pipe member 47. The pipe member 47 is configured to return the cooling water stored in the storage tank 71 to the cooling water circulation path 50 that includes the engine 33 and the radiator 51. In a top view, the pipe member 47 is connected to the center of the tank underside 74 in a direction perpendicular to the rotation axis 101 of the fan 63.

[0101] According to this configuration, the connection port of the pipe member 47 on the tank lower surface 74 is less likely to be exposed to the cooling water, so that air can be prevented from entering the circulation path 50 of the cooling water through the pipe member 47.

[0102] The hydraulic excavator 10 further includes a shroud 62 that covers the outer periphery of the fan 63. The storage tank 71 is disposed above the shroud 62.

[0103] According to this configuration, the cooling device 40 including the radiator 51, the storage tank 71, and the shroud 62 can be configured compactly.

[0104] The storage tank 71 further has a third tank side surface 77. The third tank side surface 77 faces the radiator 51 with a gap in the axial direction of the rotation shaft 101 of the fan 63. The shroud 62 has an opposing surface 69. The opposing surface 69 is provided alongside the third tank side surface 77 in the up-down direction. The opposing surface 69 faces the radiator 51 with a gap in the axial direction of the rotation shaft 101 of the fan 63. The third tank side surface 77 is positioned at a position aligned with the opposing surface 69 in the axial direction of the rotation shaft 101 of the fan 63, or at a position farther from the radiator 51 than the opposing surface 69 in the axial direction of the rotation shaft 101 of the fan 63.

[0105] According to this configuration, the storage tank 71 is less likely to get in the way when performing maintenance on the radiator 51 through the gap between the radiator 51 and the storage tank 71 and the shroud 62. This improves the ease of maintenance of the radiator 51.

[0106] The radiator 51 also includes a core portion 52 and an upper tank portion 53. In the core portion 52, the coolant flows while exchanging heat with the outside air. The upper tank portion 53 is provided above the core portion 52. The upper tank portion 53 forms a collection space 59 in which the coolant collects. The upper tank portion 53 has a radiator upper surface 55 and an upper tank lower surface 56 that faces the radiator upper surface 55 with the collection space 59 in between.

[0107] The tank lower surface 74 is positioned higher than the upper tank lower surface 56. With this configuration, the air flowing toward the core portion 52 as the fan 63 rotates can easily reach every corner of the core portion 52. This improves the cooling efficiency of the coolant in the radiator 51.

[0108] Alternatively, the tank lower surface 74 is disposed at the same height as the upper tank lower surface 56 or at a position lower than the upper tank lower surface 56. With this configuration, the capacity of the storage space 79 of the storage tank 71 can be increased.

[0109] The present disclosure is applicable to various types of work machines equipped with a cooling device for cooling engine coolant. The work machine in the present disclosure may be, for example, a bulldozer, a wheel loader, a motor grader, a crane, or a forestry machine.

[0110] (Embodiment 2) 16 is a perspective view showing a cooling device for a hydraulic excavator according to embodiment 2. The hydraulic excavator according to this embodiment basically has the same structure as the hydraulic excavator according to embodiment 1. Hereinafter, description of the overlapping structure will not be repeated.

[0111] 16, in the present embodiment, storage tank 71 is arranged on the opposite side of shroud 62, with oil cooler 41 and radiator 51 sandwiched between them, in the axial direction of rotation shaft 101 of fan 63. Storage tank 71 is provided upstream of radiator 51 in the direction of air flow formed as fan 63 rotates.

[0112] The hydraulic excavator has a stay 96. The stay 96 is fixed to a support member 81. The storage tank 71 is placed on the stay 96. The storage tank 71 is fastened to the stay 96. The storage tank 71 is supported by the support member 81 via the stay 96.

[0113] According to the hydraulic excavator of the second embodiment configured in this manner, the same effects as those described in the first embodiment can be achieved.

[0114] (Embodiment 3) 17 is a top view showing a cooling device and a fan of a hydraulic excavator according to embodiment 3. The hydraulic excavator according to this embodiment basically has the same structure as the hydraulic excavator according to embodiment 1. Hereinafter, description of the overlapping structure will not be repeated.

[0115] 17, in this embodiment, storage tank 71 is provided alongside radiator 51 in a horizontal direction perpendicular to rotation axis 101 of fan 63. Storage tank 71 may be supported by support member 81 in FIG. 16, or may be supported by a member separate from support member 81.

[0116] According to the hydraulic excavator of the third embodiment configured as described above, the same effects as those described in the first embodiment can be achieved.

[0117] (Fourth embodiment) Fig. 18 is a perspective view showing a cooling device for a hydraulic excavator in embodiment 4. Fig. 19 is a circuit diagram showing an engine cooling system in which the cooling device in Fig. 18 is applied. Fig. 20 is a cross-sectional view showing the cooling device as seen in the direction of the arrows on line XX-XX in Fig. 18.

[0118] The hydraulic excavator according to this embodiment basically has the same structure as the hydraulic excavator according to embodiment 1. Hereinafter, description of the overlapping structure will not be repeated.

[0119] As shown in FIGS. 18 to 20, the hydraulic excavator has a water supply cap 161, a tank cap 72, a mounting block 167, and a pipe 151.

[0120] The water supply cap 161 is provided to close a water inlet provided in the storage tank 71. The water supply cap 161 replaces the tank cap 72 shown in Figures 4 and 5 and is provided in the recess 80 on the tank top surface 73. When assembling the cooling device 40, the water supply cap 161 is removed from the storage tank 71, and cooling water is introduced into the radiator 51 through the opened water inlet of the storage tank 71.

[0121] The tank cap 72 has a pressure release function. The tank cap 72 opens when the internal pressure of the storage tank 71 exceeds a preset upper limit value, thereby releasing the pressurized air in the storage tank 71. The tank cap 72 does not open within a normal range in which the internal pressure of the storage tank 71 changes.

[0122] The tank cap 72 is provided at a position spaced apart from the storage tank 71. The tank cap 72 is provided at a position offset from the tank upper surface 73 in a top view. The tank cap 72 is attached to a mounting block 167. The mounting block 167 is provided at a position spaced above the radiator upper surface 55. The mounting block 167 is fastened to a retaining bracket 166 that holds the radiator 51 inside the support member 81 (see FIG. 4).

[0123] Tank cap 72 is provided above radiator upper surface 55. Tank cap 72 is provided at a position facing a third tank side surface 77 of storage tank 71 in the horizontal direction. Tank cap 72 is provided at a step between radiator upper surface 55 and a tank upper surface 73 that is positioned higher than radiator upper surface 55.

[0124] The piping 151 connects the storage tank 71 and the tank cap 72. One end of the piping 151 is connected to the storage tank 71 via a water supply cap 161. The other end of the piping 151 is connected to the tank cap 72 via a mounting block 167. The storage space 79 inside the storage tank 71 is connected to the tank cap 72 through the piping 151. A drain piping 153 is further connected to the tank cap 72.

[0125] The piping 151 may be any pipe member that forms a fluid flow path, and may be, for example, a rubber hose.

[0126] The tank cap 72 is provided at a position offset to the right from the water supply cap 161 in the left-right direction. The tank cap 72 is provided at a position offset rearward from the water supply cap 161 in the front-rear direction. The tank cap 72 and the water supply cap 161 are provided at positions offset from each other in the left-right direction and the front-rear direction.

[0127] 20 , the tank cap 72 has a cap upper surface 168. The cap upper surface 168 is disposed at a position higher than the tank upper surface 73. The cap upper surface 168 may be disposed at the same height as the tank upper surface 73, or may be disposed at a position lower than the tank upper surface 73.

[0128] Fig. 21 is a cross-sectional view showing the tank cap in Fig. 18. As shown in Fig. 20 and Fig. 21, the tank cap 72 has a cap body 174, a valve body 171, and a coil spring 173.

[0129] The cap body 174 extends in the vertical direction and has a cylindrical shape that is closed at its upper end and open at its lower end. The cap body 174 has an overall cylindrical shape centered on the central axis 170. The lower end of the cap body 174 is connected to the mounting block 167.

[0130] Valve element 171 is housed within cap body 174. Valve element 171 is provided inside cap body 174 so as to be able to slide up and down along central axis 170. Coil spring 173 is housed within cap body 174. Coil spring 173 is provided alongside valve element 171 in the up and down direction. A downward elastic force is applied to valve element 171 by coil spring 173.

[0131] 18 to 21, the valve element 171 has a valve seat 172. The valve seat 172 is made of an elastic body. Below the valve seat 172, a first space 176 is formed, which is connected to the storage space 79 inside the storage tank 71 via the piping 151, and above the valve seat 172, a second space 177 is formed, which is connected to the drain piping 153.

[0132] The cap body 174 has an abutment portion 175. The abutment portion 175 faces the valve seat 172 in the up-down direction and extends in an annular shape centered on the central axis 170. The valve seat 172 abuts against the abutment portion 175 by receiving an elastic force from the coil spring 173. This results in a closed valve state in which communication between the first space 176 and the second space 177 is blocked.

[0133] When the internal pressure of the storage tank 71 exceeds a preset upper limit, the pressure from the first space 176 toward the second space 177 overcomes the elastic force of the coil spring 173, causing the valve element 171 to slide upward. This opening movement of the valve element 171 separates the valve seat 172 from the abutment portion 175. The pressurized air in the storage tank 71 passes through the piping 151 and is released from the tank cap 72.

[0134] If the tank cap 72 is attached directly to the storage tank 71 (the form shown in FIGS. 4 and 5), there is a possibility that the valve disc 171 (valve seat 172) will be submerged in the cooling water in the storage tank 71 on the side of the first space 176 when the body of the hydraulic excavator tilts. If the surface of the cooling water fluctuates due to vibration while the valve disc 171 (valve seat 172) is submerged in the cooling water, a small amount of cooling water may leak from the first space 176 into the second space 177. This phenomenon leads to a decrease in the amount of cooling water circulating through the engine's cooling system.

[0135] As shown in Figures 18 and 19, the hydraulic excavator in this embodiment includes a tank cap 72 having a valve body 171, and piping 151 connecting the storage tank 71 and the tank cap 72. With this configuration, an air reservoir can be provided in the piping 151 connecting the storage tank 71 and the tank cap 72. Therefore, even if the body of the hydraulic excavator is tilted, the air reservoir in the piping 151 can prevent cooling water from entering from the storage tank 71 toward the tank cap 72. This can prevent the above-mentioned phenomenon of a small amount of cooling water leaking from the tank cap 72.

[0136] Furthermore, the tank cap 72 is provided above the radiator upper surface 55. According to this configuration, the tank cap 72 is disposed at a step in the height direction that occurs between the radiator upper surface 55 and the tank upper surface 73, which is disposed at a position higher than the radiator upper surface 55. This makes it possible to prevent the height of the cooling device 40 from increasing due to the installation of the tank cap 72.

[0137] 22 and 23 are top views showing the storage tank and tank cap in FIG. 18, and piping routed between the storage tank and the tank cap.

[0138] 22 and 23, the piping 151 is arranged so as to be curved between the storage tank 71 (water supply cap 161) and the tank cap 72. The piping 151 is arranged so as to be curved in an S-shape between the storage tank 71 (water supply cap 161) and the tank cap 72.

[0139] Pipe 151 has a bent portion 180 on the path between storage tank 71 (water supply cap 161) and tank cap 72. Bent portion 180 is bent so as to form a convex shape in at least one direction on tank upper surface 73. Bent portion 180 is bent so as to form a convex shape in at least one direction included in the plane of tank upper surface 73. Bent portion 180 is bent so as to form a convex shape in at least one direction included in a horizontal plane.

[0140] 22 , piping 151 has first bent portions 181 and 183 as the bent portion 180. First bent portion 181 is located on the pipeline of piping 151 between storage tank 71 and first bent portion 183. First bent portion 183 is located on the pipeline of piping 151 between first bent portion 181 and tank cap 72.

[0141] The first bent portion 181 is bent so as to form a convex shape facing towards the right. The first bent portion 181 is bent so as to form a convex shape facing towards the right. The first bent portion 181 has a protruding end 182. The protruding end 182 is located at the rightmost part of the first bent portion 181. The first bent portion 181 extends from the protruding end 182 towards the storage tank 71 while curving diagonally forward and left. The first bent portion 181 extends from the protruding end 182 towards the tank cap 72 while curving diagonally backward and left.

[0142] The first bent portion 183 is bent to form a convex shape facing left. The first bent portion 183 is bent to form a convex shape facing left. The first bent portion 183 has a protruding end 184. The protruding end 184 is located at the leftmost part of the first bent portion 183. The first bent portion 183 extends from the protruding end 184 toward the storage tank 71 while curving diagonally forward to the right. The first bent portion 183 extends from the protruding end 184 toward the tank cap 72 while curving diagonally backward to the right.

[0143] With this configuration, even if the body of the hydraulic excavator tilts to the left or right, an air reservoir is more reliably provided within the pipe 151, thereby preventing the phenomenon of minute amounts of cooling water leaking from the tank cap 72.

[0144] More specifically, a first bent portion 181 that bends to form a convex shape toward the right and a first bent portion 183 that bends to form a convex shape toward the left are provided on the pipeline of piping 151. Air in piping 151 cannot proceed from a higher position to a lower position.

[0145] When the body of the hydraulic excavator tilts downward to the right, protruding end 182 is located at the lowest position in first bent portion 181, and protruding end 184 is located at the highest position in first bent portion 183. In this case, air in the section of first bent portion 181 closer to tank cap 72 than protruding end 182 cannot pass protruding end 182 and proceed toward storage tank 71, and air in the section of first bent portion 183 closer to storage tank 71 than protruding end 184 cannot proceed toward storage tank 71.

[0146] When the body of the hydraulic excavator tilts downward to the left, protruding end 182 is positioned at the highest position in first bent portion 181, and protruding end 184 is positioned at the lowest position in first bent portion 183. In this case, air in the section of first bent portion 181 closer to storage tank 71 than protruding end 182 cannot proceed toward storage tank 71, and air in the section of first bent portion 183 closer to tank cap 72 than protruding end 184 cannot proceed beyond protruding end 184 toward storage tank 71.

[0147] 23, the pipe 151 further includes a second bent portion 185 as the bent portion 180. The second bent portion 185 partially overlaps with the first bent portion 181 in FIG. 22 on the pipeline of the pipe 151.

[0148] The second bent portion 185 is bent to form a convex shape facing forward. The second bent portion 185 is bent to form a convex shape facing forward. The second bent portion 185 has a protruding end 186. The protruding end 186 is located at the frontmost part of the second bent portion 185. The second bent portion 185 extends from the protruding end 186 toward the storage tank 71 while curving diagonally rearward to the left. The second bent portion 185 extends from the protruding end 186 toward the tank cap 72 while curving diagonally rearward to the right.

[0149] With this configuration, even if the body of the hydraulic excavator tilts forward or backward, an air reservoir can be more reliably provided within the piping 151, thereby preventing the phenomenon of minute amounts of cooling water leaking from the tank cap 72.

[0150] More specifically, a second bent portion 185 that bends to form a convex shape toward the front is provided on the conduit of piping 151. When the body of the hydraulic excavator tilts downward with the front end facing downward, the protruding end 186 is located at the lowest position in second bent portion 185. In this case, air in the section of second bent portion 185 closer to tank cap 72 than protruding end 186 cannot pass over protruding end 186 and proceed toward storage tank 71. When the body of the hydraulic excavator tilts downward with the rear end facing downward, the protruding end 186 is located at the highest position in second bent portion 185. In this case, air in the section of second bent portion 185 closer to storage tank 71 than protruding end 186 cannot proceed toward storage tank 71.

[0151] The pipe 151 may have a second bent portion on the path between the storage tank 71 and the tank cap 72, the second bent portion being bent so as to form a convex shape facing rearward.

[0152] Fig. 24 is a top view showing a modified example of the first bent portion in Fig. 22. Fig. 24 shows the path of the pipe 151 (151A, 151B) routed between the water supply cap 161 and the tank cap 72.

[0153] 24, the pipe 151 may have only one first bent portion 181 on the path between the water supply cap 161 and the tank cap 72. In this case, the first bent portion 181 may be configured to bend so as to form a convex shape toward the right (pipe 151A), or may be configured to bend so as to form a convex shape toward the left (pipe 151B).

[0154] 22 has a plurality of first bends 181, 183 on the path between the water supply cap 161 and the tank cap 72. In this case, the air in the pipe 151 is less likely to escape due to the storage tank 71, so that the phenomenon of minute amounts of cooling water leaking from the tank cap 72 can be more reliably prevented.

[0155] Fig. 25 is a perspective view showing a modified example of the cooling device for the hydraulic excavator in Fig. 18. In Fig. 25, the interior of the storage tank 71 is drawn in a see-through manner. Fig. 26 is a cross-sectional view showing the storage tank and the tank cap as seen in the direction of the arrows on line XXVI-XXVI in Fig. 25.

[0156] 25 and 26, in this modification, tank cap 72 is connected to tank upper surface 73 of storage tank 71. Tank upper surface 73 is provided with connection port 191. Connection port 191 is a through-hole that penetrates tank upper surface 73. Tank cap 72 is connected to connection port 191.

[0157] The storage tank 71 further has a wall portion 193. The wall portion 193 is provided inside the storage tank 71. The wall portion 193 is provided so as to define a space 192 surrounding the connection port 191 inside the storage tank 71. The connection port 191 opens to the space 192 inside the storage tank 71. The first space 176 in the tank cap 72 communicates with the space 192 inside the storage tank 71.

[0158] The space 192 is formed by being surrounded by the tank upper surface 73, the wall portion 193, and the fourth tank side surface 78. The space 192 is provided at a position spaced above the tank lower surface 74.

[0159] A through-hole 194 is provided in the wall portion 193. The through-hole 194 is provided to communicate between the inside and outside of the space 192. The through-hole 194 is provided to communicate between the space 192 and the storage space 79 outside the space 192. The cooling water in the storage tank 71 attempts to enter from the storage space 79 toward the space 192 through the through-hole 194. However, because the space 192 is filled with air, the cooling water only enters the space 192 up to the position of the through-hole 194 within a normal range in which the internal pressure of the storage tank 71 changes.

[0160] In this modification, an air reservoir can be provided in the space 192 between the tank cap 72 and the cooling water in the space 192 that has advanced up to the position of the through-hole 194. Therefore, even if the body of the hydraulic excavator is tilted, the air reservoir in the space 192 can prevent the cooling water from entering from the storage tank 71 toward the tank cap 72. This can prevent a small amount of cooling water from leaking from the tank cap 72.

[0161] The configuration and effects of the hydraulic excavator according to the fourth embodiment described above will now be summarized.

[0162] The hydraulic excavator further includes a tank cap 72 and a pipe 151. The tank cap 72 has a valve body 171. The pipe 151 connects the storage tank 71 and the tank cap 72 together.

[0163] According to this configuration, even if the body of the hydraulic excavator tilts, the provision of an air reservoir in the piping 151 can prevent the cooling water from entering from the storage tank 71 toward the tank cap 72. This can prevent a small amount of cooling water from leaking from the tank cap 72.

[0164] Furthermore, the tank cap 72 is provided above the radiator upper surface 55. With this configuration, an increase in the height of the cooling device 40 due to the installation of the tank cap 72 can be suppressed.

[0165] Furthermore, the piping 151 has a bent portion 180 on the path between the storage tank 71 and the tank cap 72. The bent portion 180 is bent so as to form a convex shape in at least one direction on the tank upper surface 73. With this configuration, an air reservoir can be more reliably formed in the piping 151 even when the body of the hydraulic excavator is tilted.

[0166] The hydraulic excavator further includes a tank cap 72. The tank cap 72 has a valve body 171. A connection port 191 is provided on the tank top surface 73. The tank cap 72 is connected to the connection port 191. The storage tank 71 further includes a wall portion 193. The wall portion 193 defines a space 192 surrounding the connection port 191 within the storage tank 71. A through hole 194 is provided in the wall portion 193. The through hole 194 connects the inside and outside of the space 192.

[0167] According to this configuration, even if the body of the hydraulic excavator tilts, the provision of an air reservoir in the space 192 makes it possible to prevent the cooling water from entering from the storage tank 71 toward the tank cap 72. This makes it possible to prevent a small amount of cooling water from leaking from the tank cap 72.

[0168] Furthermore, the valve element 171 opens when the internal pressure of the storage tank 71 exceeds a predetermined upper limit. With this configuration, the pressure inside the storage tank 71 can be released by the opening operation of the valve element 171.

[0169] According to the hydraulic excavator of the fourth embodiment configured as described above, the same effects as those described in the first embodiment can be achieved.

[0170] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0171] The present disclosure is applicable to various types of work machines equipped with a cooling device for cooling engine coolant. [Explanation of symbols]

[0172] 10 Hydraulic excavator, 12 Work equipment, 14 Boom, 15, 17, 19 Hydraulic cylinder, 16 Arm, 18 Bucket, 21 Main body, 22 Traveling device, 23 Track, 24 Traveling motor, 25 Swing body, 26 Operator's cab, 28 Counterweight, 29 Exterior cover, 30 Ventilation hole, 31 Engine room, 33 Engine, 34 Crankshaft, 35 Flywheel housing, 36 Hydraulic pump, 38 Ventilation space, 40 Cooling device, 41 Oil cooler, 42, 43, 44, 45, 47 Pipe members, 46 Pump, 50 Circulation path, 51 Radiator, 52 Core part, 53 Upper tank part, 54 Lower tank part, 55 Radiator top surface, 56 Upper tank bottom surface, 57 Tube, 58 Fin, 59, 60 Collecting space, 62 Shroud, 63 Fan, 64 Cylindrical portion, 65 Base, 66 Shaft portion, 67 Blade portion, 68 Top plate portion, 69 Opposing surface, 71 Storage tank, 72 Tank cap, 73 Tank top surface, 74 Tank bottom surface, 75 First tank side surface, 76 Second tank side surface, 77 Third tank side surface, 78 Fourth tank side surface, 79 Storage space, 80, 91 Recess, 81 Support member, 82 Step, 86 Extension portion, 87 Notch portion, 92 Guide portion, 93 Cylindrical portion, 94 Tapered portion, 96 Stay, 101 Rotating shaft, 110, 120 Area, 121, 122 Air layer, 151, 151A, 151B Piping, 153 Drain pipe, 161 Water supply cap, 166 Retaining bracket, 167 Mounting block, 168 Upper surface of cap, 170 central axis, 171 valve body, 172 valve seat, 173 coil spring, 174 cap body, 175 abutment portion, 176 first space, 177 second space, 180 bent portion, 181, 183 first bent portion, 182, 184, 186 protruding end, 185 second bent portion, 191 connection port, 192 space, 193 wall portion, 194 through hole.

Claims

1. A radiator, a fan disposed opposite the radiator; a storage tank that stores the cooling water from the radiator without contacting the atmosphere and is provided alongside the radiator in a direction of the rotation axis of the fan, the radiator has a radiator top surface; The storage tank has an upper tank surface and a lower tank surface, The upper surface of the tank is located at a higher position than the upper surface of the radiator, The lower surface of the tank is located at a position lower than the upper surface of the radiator, a width of the storage tank in a predetermined direction that is perpendicular to the rotation axis of the fan and parallel to the horizontal direction, when viewed from above, is greater than a width of the radiator in the predetermined direction that is perpendicular to the rotation axis of the fan and parallel to the horizontal direction.

2. the storage tank further has a first tank side surface and a second tank side surface opposite the first tank side surface, 2. The work machine according to claim 1, wherein, in a top view, the first tank side surface is located in an area on one side of the rotation shaft of the fan, and the second tank side surface is located in an area on the other side of the rotation shaft of the fan.

3. The work machine according to claim 2 , wherein, in a top view, a distance between a rotation axis of the fan and at least one of the first tank side surface and the second tank side surface is greater than a radius of the fan.

4. a pipe member configured to return the cooling water stored in the storage tank to a cooling water circulation path including the engine and the radiator; The work machine according to claim 1 , wherein the pipe member is connected to a center portion of the lower surface of the tank in a direction perpendicular to the rotation axis of the fan when viewed from above.

5. Further provided is a shroud that covers an outer periphery of the fan, The work machine according to claim 1 , wherein the storage tank is disposed above the shroud.

6. the storage tank further has a third tank side surface facing the radiator across a gap in a rotational axis direction of the fan, the shroud is provided alongside a side surface of the third tank in the up-down direction and has an opposing surface that faces the radiator with a gap in between in the direction of the rotation axis of the fan, 6. The work machine according to claim 5, wherein the third tank side surface is disposed in a position aligned with the opposing surface in the direction of the rotational axis of the fan, or in a position farther from the radiator than the opposing surface in the direction of the rotational axis of the fan.

7. The radiator includes a core portion through which coolant flows while exchanging heat with outside air, and an upper tank portion provided above the core portion and forming a collection space in which the coolant collects, the upper tank portion has an upper surface of the radiator and an upper tank lower surface facing the upper surface of the radiator across the collecting space, The work machine according to claim 5 or 6, wherein the tank lower surface is located at a higher position than the upper tank lower surface.

8. The radiator includes a core portion through which coolant flows while exchanging heat with outside air, and an upper tank portion provided above the core portion and forming a collection space in which the coolant collects, the upper tank portion has an upper surface of the radiator and an upper tank lower surface facing the upper surface of the radiator across the collecting space, The work machine according to claim 1 , wherein the tank lower surface is disposed at the same height as the upper tank lower surface or at a position lower than the upper tank lower surface.

9. a tank cap having a valve body; The work machine according to claim 1 , further comprising a pipe connecting the storage tank and the tank cap.

10. The work machine according to claim 9 , wherein the tank cap is provided above an upper surface of the radiator.

11. The work machine according to claim 9 or 10, wherein the piping has a bent portion on a path between the storage tank and the tank cap, the bent portion being convex in at least one direction on the top surface of the tank.

12. a tank cap having a valve body; A connection port to which the tank cap is connected is provided on the top surface of the tank, the storage tank further includes a wall portion defining a space surrounding the connection port within the storage tank, The work machine according to claim 1 , wherein the wall portion is provided with a through-hole that connects the inside and outside of the space.

13. The work machine according to claim 9 or 12, wherein the valve element opens when the internal pressure of the storage tank exceeds a predetermined upper limit value.

14. A radiator, a fan disposed opposite the radiator; a storage tank that stores the cooling water from the radiator without contacting the atmosphere and is provided alongside the radiator in a direction of the rotation axis of the fan, the radiator has a radiator top surface; The storage tank has an upper tank surface and a lower tank surface, The upper surface of the tank is located at a higher position than the upper surface of the radiator, The lower surface of the tank is located at a position lower than the upper surface of the radiator, the storage tank further has a first tank side surface and a second tank side surface opposite the first tank side surface, A work machine wherein, when viewed from above, the first tank side surface is located in an area on one side of the rotation shaft of the fan, and the second tank side surface is located in an area on the other side of the rotation shaft of the fan.

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