Work machine

Abstract

To provide a work machine being allowed to properly place a plurality of structures including a cab.SOLUTION: A work machine is provided with an engine 40, a cab 332 in which an operator rides, and a cooling unit 60. The cooling unit 60 includes a heat exchanger 70 through which a fluid to be cooled passes, and cooling fans 61 and 62 for cooling the fluid to be cooled by sending fresh air to the heat exchanger 70. The whole of the cooling unit 60 is placed behind the cab 332. The cooling unit 60 has a part placed behind the engine 40.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] An example of the prior art is a work machine described in Japanese Patent Laid-Open Publication No. 2009-120036 (Patent Document 1). This work machine is equipped with a cooling core, and in a plan view, a portion of the cab is positioned over the cooling core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-120036 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for expanding the space inside the cab of a work machine so that more equipment can be installed inside the cab where the operator sits. However, expanding the space inside the cab makes it difficult to arrange the equipment mounted on the limited surface area of ​​the body frame. If the cab is positioned so that it protrudes from the body frame, the advantage of a small turning radius work machine is lost.

[0005] The present disclosure proposes a work machine capable of appropriately arranging a plurality of structures, including a cab. [Means for solving the problem]

[0006] According to the present disclosure, a work machine is proposed that includes an engine, a cab for an operator, and a cooling unit. The cooling unit includes a heat exchanger through which a fluid to be cooled flows, and a cooling fan that cools the fluid to be cooled by sending outside air to the heat exchanger. The entire cooling unit is located rearward of the cab. The cooling unit has a portion located rearward of the engine. [Effects of the Invention]

[0007] According to the work machine according to the present disclosure, it is possible to appropriately arrange a plurality of structures including the cab. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view schematically illustrating a configuration of a hydraulic excavator. [Figure 2] FIG. 1 is a schematic block diagram showing a system configuration of a hydraulic excavator. [Figure 3] FIG. 2 is a schematic diagram showing the arrangement of devices in the engine compartment as seen from the rear. [Figure 4] FIG. 2 is a schematic plan view showing the arrangement of each structure on a frame. [Figure 5] FIG. 2 is a schematic diagram showing the engine and the cooling unit as seen from the side. [Figure 6] FIG. 2 is a schematic perspective view of a right rear corner of the cab. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. In the drawings, configurations may be omitted or simplified for the sake of convenience. It is also intended from the beginning that any configurations may be extracted from the embodiments and arbitrarily combined.

[0010] <Overall structure> In the embodiment, a hydraulic excavator 1 will be described as an example of a work machine. FIG.

[0011] 1, the hydraulic excavator 1 includes a work implement 2 and a vehicle body 3. The vehicle body 3 includes a traveling body 31, a swing circle 32, a rotating body 33, and a swing motor 35.

[0012] The running body 31 has a pair of left and right track devices 311. Each of the pair of left and right track devices 311 has a travel motor 312 and a track. The pair of left and right tracks are rotationally driven by the travel motors 312, causing the hydraulic excavator 1 to self-propel.

[0013] The swing circle 32 is connected to a swing motor 35. The swing circle 32 rotates due to the rotational drive of the swing motor 35. The travel motor 312 and the swing motor 35 are hydraulic motors driven by hydraulic oil supplied from a hydraulic source (hydraulic pump 45 and hydraulic oil tank 46; see FIG. 2).

[0014] The revolving body 33 is installed on the running body 31 via the swing circle 32. The revolving body 33 revolves relative to the running body 31 as the swing circle 32 rotates.

[0015] The rotating body 33 has a frame 331 to which the work machine 2 is attached, a cab 332 in which the operator sits, an engine room 333, and a counterweight 334. The cab 332 is disposed, for example, on the front left side (front side of the vehicle) of the rotating body 33. The engine room 333 is disposed at the rear of the rotating body 33 (rear side of the vehicle). The counterweight 334 is disposed at the rear end of the rotating body 33.

[0016] The work implement 2 is supported by the frame 331 on the front side of the revolving unit 33, for example on the right side of the cab 332. The work implement 2 is supported by the vehicle body 3 and is disposed in front of the vehicle body 3. The work implement 2 has a boom 21, an arm 22, a bucket 23, etc. The bucket 23 is an example of an attachment that can be attached to the tip of the work implement 2.

[0017] In this embodiment, the positional relationship of each part of the hydraulic excavator 1 will be described with reference to the work implement 2.

[0018] The boom 21 of the work implement 2 rotates around a boom foot pin provided at the base end of the boom 21 relative to the rotating unit 33. A specific portion of the boom 21 that rotates relative to the rotating unit 33, for example the tip of the boom 21, moves along an arc-shaped trajectory, and a plane that includes this arc is specified. When the hydraulic excavator 1 is viewed from above, this plane is represented as a straight line. The direction in which this straight line extends is the fore-and-aft direction of the vehicle body 3 of the hydraulic excavator 1 or the fore-and-aft direction of the rotating unit 33, and will hereinafter also be referred to simply as the fore-and-aft direction. The left-and-right direction (vehicle width direction) of the vehicle body 3 of the hydraulic excavator 1 or the left-and-right direction of the rotating unit 33 is a direction that is perpendicular to the fore-and-aft direction in a plan view, and will hereinafter also be referred to simply as the left-and-right direction.

[0019] In the front-to-rear direction, the side where the work implement 2 protrudes from the vehicle body 3 of the hydraulic excavator 1 is the front direction, and the direction opposite to the front direction is the rear direction. Looking forward, the right and left sides in the left-right direction are the right direction and the left direction, respectively.

[0020] The front-to-rear direction refers to the front-to-rear direction of an operator seated in the driver's seat inside the cab 332. The direction facing the operator seated in the driver's seat is the forward direction, and the direction behind the operator seated in the driver's seat is the rearward direction. The left-to-right direction refers to the left-to-right direction of an operator seated in the driver's seat. The right and left sides of the operator seated in the driver's seat when facing directly ahead are the right and left directions, respectively.

[0021] In FIG. 1 and the following figures, the front-rear direction is indicated by an arrow X, the left-right direction is indicated by an arrow Y, and the up-down direction is indicated by an arrow Z.

[0022] The boom 21 is attached to the revolving unit 33. The base end of the boom 21 is rotatably connected to the revolving unit 33 by a boom foot pin (not shown). The boom 21 can be driven by a boom cylinder 211. The boom cylinder 211 is driven by hydraulic oil supplied from a hydraulic source. This drive allows the boom 21 to rotate up and down relative to the revolving unit 33 around the boom foot pin.

[0023] The arm 22 is attached to the tip of the boom 21. The base end of the arm 22 is rotatably connected to the tip of the boom 21 by a boom tip pin 242. The arm 22 can be driven by an arm cylinder 221. The arm cylinder 221 is driven by hydraulic oil supplied from a hydraulic source. This drive allows the arm 22 to rotate up and down relative to the boom 21 around the boom tip pin 242.

[0024] The bucket 23 is attached to the tip of the arm 22. The bucket 23 is rotatably connected to the tip of the arm 22 by an arm tip pin 243. The bucket 23 can be driven by a bucket cylinder 231. The bucket cylinder 231 is driven by hydraulic oil supplied from a hydraulic source. This drive allows the bucket 23 to rotate vertically relative to the arm 22 around the arm tip pin 243. In this manner, the work implement 2 can be driven.

[0025] The counterweight 334 is a weight placed at the rear end of the rotating unit 33 to balance the vehicle body during excavation work, etc. The hydraulic excavator 1 is formed as a short rear swing hydraulic excavator in which the swing radius of the rear face of the counterweight 334 is reduced. The rear face of the counterweight 334 is formed in an arc shape centered on the swing center of the rotating unit 33 when viewed from above.

[0026] <System configuration> FIG. 2 is a schematic block diagram showing the system configuration of the hydraulic excavator 1. The hydraulic excavator 1 is equipped with an engine 40. The engine 40 is housed in an engine compartment 333 (FIG. 1). The engine 40 is disposed in the center of the engine compartment 333 in the left-right direction. The engine 40 is a drive source for the operation of the hydraulic excavator 1. The engine 40 is an internal combustion engine, such as a diesel engine. The rotation speed of the engine 40 is controlled by adjusting the amount of fuel injected into the cylinder. This adjustment is performed by controlling a governor attached to a fuel injection pump of the engine 40.

[0027] An output shaft 41 of the engine 40 is connected to a power takeoff 43. The driving force generated by the engine 40 is transmitted to a hydraulic pump 45 via the power takeoff 43. The hydraulic pump 45 is driven by the engine 40. The hydraulic pump 45 draws in and discharges hydraulic oil contained in a hydraulic oil tank 46.

[0028] Hydraulic oil discharged from hydraulic pump 45 is supplied to various hydraulic actuators via main valve 47. The hydraulic actuators include boom cylinder 211, arm cylinder 221, bucket cylinder 231, swing motor 35, and travel motor 312, which are also shown in FIG. 1. Engine 40 is the drive source for operating work implement 2, swinging of swing unit 33, and traveling of travel unit 31.

[0029] The operation of the hydraulic excavator 1 is controlled by controlling the supply and discharge of hydraulic oil to the hydraulic actuators. The hydraulic oil is oil that is supplied to the hydraulic actuators to operate the hydraulic actuators. The hydraulic oil discharged from the hydraulic actuators is returned to the hydraulic oil tank 46 via the main valve 47.

[0030] An alternator 44 is connected to the power takeoff section 43. The alternator 44 operates as a generator. The alternator 44 generates electricity by rotating upon receiving driving force generated by the engine 40. The rotation speed of the alternator 44 is set in accordance with the rotation speed of the engine 40. The higher the rotation speed of the engine 40, the higher the rotation speed of the alternator 44, and the greater the amount of electricity generated by the alternator 44.

[0031] The alternator 44 and the battery 50 are electrically connected. The electric power generated by the alternator 44 is stored in the battery 50. The battery 50 is an electric power storage device that stores electric power. The battery 50 is a secondary battery such as a nickel-metal hydride battery or a lithium-metal hydride battery.

[0032] The hydraulic excavator 1 includes a cooling unit 60. The cooling unit 60 of the embodiment includes a heat exchanger 70. The heat exchanger 70 of the embodiment includes a radiator 71, an oil cooler 72, and a CAC (Charge Air Cooler) 73.

[0033] Cooling water for the engine 40 flows inside the radiator 71. The cooling water for the engine 40 is the fluid to be cooled by the radiator 71. Hydraulic oil supplied to the hydraulic actuator flows inside the oil cooler 72. The hydraulic oil is the fluid to be cooled by the oil cooler 72. Air supplied to the engine 40 flows inside the CAC 73. The intake air of the engine 40 is the fluid to be cooled by the CAC 73.

[0034] The cooling unit 60 is equipped with a plurality of cooling fans, including a cooling fan 61 and a cooling fan 62. The heat exchanger 70 and the cooling fans 61 and 62 form an integrated cooling unit 60. The cooling fans 61 and 62 are each disposed opposite the heat exchanger 70. The cooling fans 61 and 62 generate a flow of air that passes through the engine compartment 333.

[0035] The airflow generated by the cooling fans 61, 62 cools the fluid to be cooled that flows through the heat exchanger 70. In the heat exchanger 70, heat is exchanged between the fluid to be cooled and the outside air, and the fluid to be cooled is cooled by dissipating heat from the fluid to be cooled to the outside air.

[0036] The cooling fans 61 and 62 are electric fans. The electric motors 64 and 65 are electrically connected to the battery 50. The cooling fan 61 is driven by the electric motor 64. The cooling fan 62 is driven by the electric motor 65.

[0037] Electric power stored in the battery 50 or electric power generated by the alternator 44 is supplied to the electric motors 64, 65 to drive the electric motors 64, 65. The cooling fans 61, 62 are driven by the power supplied from the battery 50 or the alternator 44, and generate a flow of air that passes through the heat exchanger 70. When the fluid to be cooled passes through the heat exchanger 70, heat is released into the air, thereby cooling the fluid to be cooled.

[0038] The hydraulic excavator 1 further includes a controller 80. The controller 80 controls the overall operation of the hydraulic excavator 1 and includes a CPU (Central Processing Unit), a non-volatile memory, a timer, and the like. The controller 80 is capable of transmitting control signals to the electric motors 64, 65. The controller 80 stores in advance a program for controlling the cooling fans 61, 62 and various data required for executing the program.

[0039] The controller 80 in the embodiment is mounted on the hydraulic excavator 1. The controller 80 does not have to be mounted on the hydraulic excavator 1. The controller 80 may be arranged external to the hydraulic excavator 1. The controller 80 may be arranged at the work site of the hydraulic excavator 1, or may be arranged in a remote location away from the work site of the hydraulic excavator 1. The hydraulic excavator 1 and the controller 80 arranged external to the hydraulic excavator 1 may constitute a control system for the hydraulic excavator 1.

[0040] The controller 80 sends a motor control signal SM1 to the electric motor 64 to control the direction and speed of rotation of the cooling fan 61. The controller 80 sends a motor control signal SM2 to the electric motor 65 to control the direction and speed of rotation of the cooling fan 62.

[0041] <Layout of cooling unit 60> The arrangement of the cooling unit 60 will now be described. Fig. 3 is a schematic diagram showing the arrangement of devices in the engine compartment 333, as viewed from the rear of the engine compartment 333. The engine 40 and the cooling unit 60 are housed in the engine compartment 333. The engine 40 is arranged in the center of the engine compartment 333 in the left-right direction.

[0042] The cooling unit 60 is disposed to the left of the engine 40. The cooling unit 60 is disposed closer to the left side of the engine compartment 333. The cooling unit 60 is disposed closer to the left side of the revolving unit 33 than the engine 40. The cooling fans 61, 62 take in outside air into the engine compartment 333 through a left air vent formed on the left side of the revolving unit 33, and send the outside air to the heat exchanger 70. The heat exchanger 70 is disposed in a position facing the left air vent.

[0043] In the engine compartment 333, the cooling fan 61 and the cooling fan 62 are arranged side by side in the vertical direction indicated by the arrow Z in the figure. Of the cooling fan 61 and the cooling fan 62, the cooling fan 61 is arranged at the bottom and the cooling fan 62 is arranged at the top. In the cooling unit 60, a plurality of electric fans are arranged side by side in the vertical direction. The cooling fan 62 is arranged above the cooling fan 61.

[0044] In the left-right direction indicated by arrow Y in the figure, cooling fans 61 and 62 are arranged between heat exchanger 70 (radiator 71, CAC 73, and oil cooler 72) and engine 40. Cooling fans 61 and 62 are arranged adjacent to heat exchanger 70 in the left-right direction and to the right of heat exchanger 70. Cooling fans 61 and 62 face heat exchanger 70.

[0045] The engine 40 and the cooling unit 60 are arranged side by side in the left-right direction. The cooling fans 61 and 62 are arranged to the left of the engine 40. The engine 40 has a left side surface 40L facing leftward, and the cooling fans 61 and 62 face the left side surface 40L of the engine 40. The cooling fans 61 and 62 are driven to rotate by electric motors 64 and 65 (FIG. 2) and generate a flow of air that flows from the left side to the right side of the vehicle body 3 of the hydraulic excavator 1.

[0046] The heat exchanger 70 is disposed on the left side of the cooling fans 61, 62, which is upstream of the airflow generated by the cooling fans 61, 62. The engine 40 is disposed on the right side of the cooling fans 61, 62, which is downstream of the airflow generated by the cooling fans 61, 62. The cooling fans 61, 62 generate an airflow that flows toward the engine 40 after passing through the heat exchanger 70. The air that has passed through the heat exchanger 70 is blown toward the engine 40, generating an airflow that flows around the engine 40. Air flows from left to right within the engine compartment 333.

[0047] The hydraulic pump 45 is disposed to the right of the engine 40. The engine 40 has a right side surface 40R facing rightward, and the hydraulic pump 45 faces the right side surface 40R of the engine 40. In the engine compartment 333, the heat exchanger 70, the cooling fans 61 and 62, the engine 40, and the hydraulic pump 45 are disposed in this order from left to right.

[0048] The radiator 71, CAC 73, and oil cooler 72 are arranged side by side in the front-to-rear direction in the engine compartment 333. The radiator 71, CAC 73, and oil cooler 72 are arranged in this order from front to rear.

[0049] The radiator 71 includes an inlet, which is an entrance through which the engine 40 cooling water flows into the radiator 71, an outlet, which is an exit through which the engine 40 cooling water flows out from the radiator 71, and a cooling core including multiple heat exchange tubes. The inlet is located at the top of the radiator 71. The outlet is located at the bottom of the radiator 71. The multiple heat exchange tubes of the cooling core form a flow path for the engine 40 cooling water from the inlet to the outlet. The flow direction of the engine 40 cooling water in the radiator 71 is downward. The engine 40 cooling water flowing in the radiator 71 forms a downward flow from top to bottom. The radiator 71 is designed so that the engine 40 cooling water enters from above and exits from below.

[0050] The oil cooler 72 includes an inlet, which is an entrance through which hydraulic oil flows into the oil cooler 72, an outlet, which is an exit through which hydraulic oil flows out of the oil cooler 72, and a cooling core including multiple heat exchange tubes. The inlet is located at the top of the oil cooler 72. The outlet is located at the bottom of the oil cooler 72. The multiple heat exchange tubes of the cooling core form a flow path for hydraulic oil from the inlet to the outlet. The flow direction of hydraulic oil within the oil cooler 72 is downward. The hydraulic oil flowing within the oil cooler 72 forms a downward flow from top to bottom. The oil cooler 72 is designed so that hydraulic oil enters from the top and exits from the bottom.

[0051] The CAC 73 includes an inlet, which is an entrance through which air supplied to the engine 40 flows into the CAC 73, an outlet, which is an exit through which air flows out of the CAC 73, and a cooling core including multiple heat exchange tubes. The inlet is located at the top of the CAC 73. The outlet is located at the bottom of the CAC 73. The multiple heat exchange tubes of the cooling core form a flow path for air from the inlet to the outlet. The air flows downward within the CAC 73. The air flowing within the CAC 73 forms a downward flow from top to bottom. The CAC 73 is designed so that air enters from above and exits from below.

[0052] The cooling fan 61 and the cooling fan 62 send outside air to the cooling core of the radiator 71 , the cooling core of the oil cooler 72 , and the cooling core of the CAC 73 .

[0053] Fig. 4 is a schematic plan view showing the arrangement of each structure on the frame 331. The left side in Fig. 4 indicates the front of the rotating body 33, the right side in Fig. 4 indicates the rear of the rotating body 33, the upper side in Fig. 4 indicates the right side of the rotating body 33, and the lower side in Fig. 4 indicates the left side of the rotating body 33. Fig. 4 schematically shows the arrangement of structures on the frame 331, including the cab 332, engine 40, and cooling unit 60.

[0054] The frame 331 has a pair of vertical plates 337, 338 near the center in the left-right direction. The vertical plates 337, 338 extend in the front-rear direction and are spaced apart in the left-right direction. The vertical plates 337, 338 are composed of plates standing in the vertical direction. A center bracket that supports the base end of the work implement 2 is provided at the front end of the vertical plates 337, 338. The work implement 2 is attached between the right vertical plate 337 and the left vertical plate 338 and is fixed in a state that allows it to move up and down.

[0055] 1 is mounted on a frame 331. The engine 40 is mounted on the rear of a center frame on the left-right central side of the frame 331. In consideration of the weight balance with the work implement 2 attached to the front of the vehicle body 3 of the hydraulic excavator 1, the engine 40 is located at the rear of the hydraulic excavator 1, away from the center bracket that supports the work implement 2 and close to the counterweight 334.

[0056] A plurality of engine mounts are attached to the vertical plates 337 and 338. The engine 40 is mounted on the engine mounts and supported by the frame 331. By providing the engine mounts on the strong vertical plates 337 and 338, it is possible to support the engine 40 on the frame 331.

[0057] The hydraulic pump 45 is disposed immediately to the right of the engine 40. Above the hydraulic pump 45, an exhaust treatment unit (not shown) is disposed for treating and purifying the exhaust gas discharged from the engine 40.

[0058] A hydraulic oil tank 46, also shown in Figure 2, is mounted on the frame 331 to the right of the right vertical plate 337. The hydraulic oil tank 46 stores hydraulic oil to be supplied to the hydraulic actuator. The hydraulic oil tank 46 is formed as a rectangular parallelepiped pressure-resistant tank. The hydraulic oil tank 46 is disposed in front of the hydraulic pump 45. The hydraulic pump 45 and the hydraulic oil tank 46 are disposed side by side in the front-to-rear direction. When the hydraulic pump 45 is operated by power from the engine 40, the hydraulic oil in the hydraulic oil tank 46 is sent to the main valve 47 (Figure 2). By disposing the hydraulic oil tank 46 near the hydraulic pump 45, the hydraulic oil can be efficiently transferred.

[0059] The cab 332 is disposed on the frame 331 to the left of the left vertical plate 338. The cab 332 is mounted on the frame 331 via a cab mount (not shown). The cab 332 has a rear surface 332Rr that faces rearward. The rear surface 332Rr of the cab 332 has a substantially flat shape.

[0060] The cooling unit 60 is mounted on the frame 331 to the left of the left vertical plate 338. The cooling unit 60 is disposed rearward of the cab 332. The cooling unit 60 is disposed so as to face the rear surface 332Rr of the cab 332. The cab 332 and the cooling unit 60 are disposed side by side in the front-to-rear direction. The entire cooling unit 60 is disposed rearward of the cab 332. The entire cooling unit 60 is disposed rearward of the rear surface 332Rr of the cab 332, and is disposed away from the cab 332. The cooling unit 60 is disposed in a position that does not overlap with the cab 332 in a plan view.

[0061] The counterweight 334 is mounted on the frame 331 behind the engine 40. A front surface 334F of the counterweight 334 forms the rear wall of the engine compartment 333. The front surface 334F of the counterweight 334 faces the engine 40 and the cooling unit 60. A recess is formed in part of the front surface 334F of the counterweight 334, and the cooling unit 60 is fitted into this recess. The rear end of the cooling unit 60 is disposed inside the recess formed in the front surface 334F of the counterweight 334.

[0062] The engine 40 is disposed forward and spaced apart from the front surface 334F of the counterweight 334. A hollow space 335 is formed between the rear surface 40Rr of the engine 40 and the front surface 334F of the counterweight 334. The space 335 is formed at a position where the cooling unit 60 (cooling fans 61, 62 and heat exchanger 70) faces each other. After passing through the heat exchanger 70, some of the air flows into the space 335. The space 335 serves as a passage for some of the air. Some of the air flows behind the engine 40 from left to right.

[0063] The space 335 extends in the left-right direction from the left side surface 40L to the right side surface 40R of the engine 40. The space 335 is formed so that the space between the rear surface 40Rr of the engine 40 and the front surface 334F of the counterweight 334 can be seen in the left-right direction.

[0064] Fig. 5 is a schematic diagram showing the engine 40 and the cooling unit 60 as seen from the side. In Fig. 5, the direction perpendicular to the paper surface is the left-right direction of the vehicle body 3. Fig. 5 schematically illustrates the engine 40 and the cooling unit 60 as seen in the left-right direction, specifically as seen facing leftward.

[0065] The engine 40 has an engine main body 40M and engine accessories 40A. The engine main body 40M includes, for example, a cylinder head, a cylinder, a crankcase, an oil pan, etc. Pistons, connecting rods, a crankshaft, a camshaft, etc. are arranged inside the engine main body 40M. An output shaft 41, also shown in FIG. 2, protrudes from the engine main body 40M. The engine accessories 40A include, for example, an intake manifold, an intake valve, a fuel injector, an exhaust valve, an exhaust manifold, an alternator, etc.

[0066] The engine accessories 40A are arranged around the engine body 40M. At least some of the engine accessories 40A are arranged above the engine body 40M. At least some of the engine accessories 40A are arranged forward of the engine body 40M. At least some of the engine accessories 40A are arranged rearward of the engine body 40M.

[0067] Cooling fan 61 and cooling fan 62 are arranged side by side in the vertical direction. Cooling fan 61 is arranged higher than cooling fan 62. Cooling fan 61 rotates around a rotation center 61C to generate an air flow. Cooling fan 62 rotates around a rotation center 62C to generate an air flow. Rotation center 61C of cooling fan 61 and rotation center 62C of cooling fan 62 are arranged side by side in the vertical direction and are arranged at the same position in the front-to-back direction indicated by arrow X in the figure.

[0068] The uppermost part of the engine accessories 40A that are arranged highest constitutes the upper surface 40S of the engine 40. The cooling fan 61 has a portion that is arranged higher than the upper surface 40S of the engine 40. The center of rotation 61C of the cooling fan 61 overlaps with the engine accessories 40A. The center of rotation 61C of the cooling fan 61 is arranged higher than the engine main body 40M. The center of rotation 61C of the cooling fan 61 is at a different position from the output shaft 41 of the engine 40. The cooling fans 61, 62 have a portion that does not overlap with the engine 40 in the fore-and-aft direction of the vehicle body. Specifically, the cooling fans 61, 62 have a portion that is arranged rearward of the engine 40.

[0069] The center of rotation 61C of cooling fan 61 and the center of rotation 62C of cooling fan 62 are disposed rearward of the output shaft 41 of engine 40. The centers of rotation 61C, 62C of all of the multiple cooling fans 61, 62 are disposed rearward of the output shaft 41 of engine 40. The cooling unit 60 has a portion located rearward of the engine 40.

[0070] The extending direction of the rotation shafts of the cooling fans 61, 62 and the extending direction of the output shaft 41 of the engine 40 are parallel to each other. The rotating shafts of the cooling fans 61, 62 and the output shaft 41 of the engine 40 extend in the left-right direction of the vehicle body 3. An electric motor 64 (FIG. 2) that drives the cooling fan 61 is disposed above the engine main body 40M. When looking at the engine 40 and the cooling fans 61, 62 in the left-right direction of the vehicle body 3, the cooling fans 61, 62 have both portions that overlap with the engine 40 and portions that do not overlap with the engine 40.

[0071] Fig. 6 is a schematic perspective view of the right rear corner of the cab 332. Referring also to Fig. 4, a recess 332H is formed in the right rear corner of the cab 332 where the right side surface 332R of the cab 332 and the rear surface 332Rr of the cab 332 intersect, with both the right side surface 332R and the rear surface 332Rr recessed. The recess 332H is formed as a hollow space. A part of the engine 40 is housed inside this recess 332H.

[0072] 4, engine 40 has a portion that overlaps with cab 332 in plan view. Cooling unit 60 does not have a portion that overlaps with cab 332 in plan view. Cooling unit 60 is disposed rearwardly relative to engine 40. This results in an arrangement in which a portion of cooling unit 60 faces left side surface 40L of engine 40 and a portion of cooling unit 60 faces space 335.

[0073] <Action and effect> Although some of the description overlaps with the above description, the characteristic configuration and effects of this embodiment can be summarized as follows.

[0074] 4, the entire cooling unit 60 is disposed rearward of the cab 332. As shown in FIGS. 4 and 5, the cooling unit 60 has a portion located rearward of the engine 40.

[0075] When expanding the space inside the cab 332, the rear surface 332Rr of the cab 332 is moved rearward to add new space inside the cab 332 without increasing the turning radius of the rotating bed 33. If the engine 40 is moved rearward at this time, the thickness of the counterweight 334 will be reduced to avoid interference between the engine 40 and the counterweight 334. The reduction in the weight of the counterweight 334 reduces the stability of the vehicle body 3. In order to ensure the weight of the counterweight 334, it is necessary not to move the engine 40 rearward even when the rear surface 332Rr of the cab 332 is moved rearward.

[0076] By not moving the engine 40 rearward but instead moving the cooling unit 60 rearward, the arrangement shown in FIGS. 4 and 5 is realized, in which the entire cooling unit 60 is positioned rearward of the cab 332 and the cooling unit 60 has a portion located rearward of the engine 40. Interference between the cab 332 and the cooling unit 60 is avoided, and by accommodating a portion of the engine 40 inside the recess 332H of the cab 332 shown in FIG. 6, interference between the cab 332 and the engine 40 is also avoided. Therefore, multiple structures including the cab 332, engine 40, and cooling unit 60 can be appropriately arranged on the frame 331.

[0077] Since cooling unit 60 has a portion located rearward of engine 40, the airflow generated by cooling fans 61, 62 can flow toward the rear of engine 40, reducing pressure loss in the airflow. Therefore, the airflow of cooling fans 61, 62 can be ensured.

[0078] 5, the center of rotation 61C of the cooling fan 61 may be located rearward of the output shaft 41 of the engine 40. The center of rotation 62C of the cooling fan 62 may be located rearward of the output shaft 41 of the engine 40. The positioning of the cooling unit 60 including the cooling fans 61, 62 and the engine 40 can be appropriately set, and an arrangement in which the cooling unit 60 has a portion located rearward of the engine 40 can be reliably achieved.

[0079] 5, both the center of rotation 61C of cooling fan 61 and the center of rotation 62C of cooling fan 62 may be located rearward of the output shaft 41 of engine 40. This allows the cooling unit 60 including cooling fans 61, 62 to be appropriately positioned relative to the engine 40, and ensures that the cooling unit 60 has a portion located rearward of the engine 40.

[0080] 2, the cooling fans 61, 62 may be electric fans driven by electric motors 64, 65. When the cooling fans 61, 62 are electric fans, the placement of the cooling fans 61, 62 is not limited by the position of the output shaft 41 of the engine 40, and the degree of freedom in placement of the cooling fans 61, 62 can be improved. The cooling fans 61, 62 can be placed in desired positions relative to the engine 40, and a placement in which a portion of the cooling unit 60 is located rearward of the engine 40 can be reliably achieved.

[0081] 4, the cooling unit 60 may face the rear surface 332Rr of the cab 332. By disposing the cooling unit 60 behind the rear surface 332Rr of the cab 332 and disposing the cooling unit 60 facing the rear surface 332Rr of the cab 332, it is possible to reliably realize an arrangement in which the entire cooling unit 60 is positioned behind the cab 332.

[0082] 3 and 4, the cooling unit 60 may be disposed to the left of the engine 40. By disposing the hydraulic pump 45, which is driven by the driving force of the engine 40, to the right of the engine 40, the distance between the hydraulic pump 45 and the hydraulic oil tank 46 can be reduced, improving the efficiency of hydraulic oil transfer. In this case, the space available for disposing the cooling unit 60 is to the left of the engine 40. By disposing the cooling unit 60 to the left of the engine 40 so that the entire cooling unit 60 is located rearward of the cab 332, the cab 332 and the cooling unit 60 can be appropriately positioned.

[0083] As shown in FIG. 4, a space 335 serving as an air passage may be formed between the engine 40 and the counterweight 334. The space 335 is formed downstream of the airflow generated by the cooling fans 61, 62, and serves as the air passage. The air passes through the hollow space 335, which has few obstacles, making it easier for the air to flow downstream, thereby reducing ventilation resistance. By forming an air passage for the cooling fans 61, 62 with low ventilation resistance, a decrease in the airflow rate of the cooling fans 61, 62 can be suppressed. Even if electric fans with a weak air-pushing force are used as the cooling fans 61, 62, a sufficient airflow rate can be ensured.

[0084] Although the hydraulic excavator 1 of the embodiment is provided with two cooling fans 61, 62, it is sufficient that the hydraulic excavator 1 is provided with at least one cooling fan. The hydraulic excavator 1 may be provided with only one cooling fan, or may be provided with three or more cooling fans.

[0085] In the embodiment, an example has been described in which two cooling fans 61, 62 are arranged at the same position in the front-to-rear direction, but the positions of the multiple cooling fans in the front-to-rear direction do not necessarily have to be the same. The multiple cooling fans may be arranged at positions offset in the front-to-rear direction. The centers of rotation of all of the multiple cooling fans do not necessarily have to be arranged rearward of the output shaft 41 of the engine 40. The multiple cooling fans may include at least one cooling fan whose center of rotation is arranged rearward of the output shaft 41 of the engine 40 and at least one cooling fan whose center of rotation is arranged forward of the output shaft 41 of the engine 40.

[0086] In the embodiment, the hydraulic excavator 1 has been described as an example of a work machine, but the invention is not limited to the hydraulic excavator 1 and the concept of the present disclosure may be applied to other types of work machines such as wheel loaders and bulldozers.

[0087] <Additional Notes> The above description includes the following additional features.

[0088] (Appendix 1) The engine and A cab in which the operator sits, a cooling unit including a heat exchanger through which a fluid to be cooled flows, and a cooling fan that sends outside air to the heat exchanger to cool the fluid to be cooled; The entire cooling unit is disposed rearward of the cab, A work machine, wherein the cooling unit has a portion located rearward of the engine.

[0089] (Appendix 2) 2. The work machine according to claim 1, wherein a center of rotation of the cooling fan is disposed rearward of an output shaft of the engine.

[0090] (Appendix 3) the cooling unit includes a plurality of the cooling fans, The work machine according to claim 2, wherein the rotation centers of all of the plurality of cooling fans are disposed rearward of the output shaft of the engine.

[0091] (Appendix 4) The work machine according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the cooling fan is an electric fan.

[0092] (Appendix 5) The work machine according to any one of Supplementary Note 1 to Supplementary Note 4, wherein the cooling unit faces a rear surface of the cab.

[0093] (Appendix 6) The work machine according to any one of Supplementary Note 1 to Supplementary Note 5, wherein the cooling unit is disposed to the left of the engine.

[0094] (Appendix 7) a counterweight disposed at a rear end of the work machine; The work machine according to any one of Supplementary notes 1 to 6, wherein a space that serves as an air passage is formed between the engine and the counterweight.

[0095] The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined not by the above description but by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0096] 1 hydraulic excavator, 2 work equipment, 3 body, 31 running body, 33 rotating body, 40 engine, 40A engine accessories, 40L left side, 40M engine body, 40R, 332R right side, 40Rr, 332Rr rear, 40S top, 41 output shaft, 45 hydraulic pump, 46 hydraulic oil tank, 60 cooling unit, 61, 62 cooling fan, 61C, 62C rotation center, 64, 65 electric motor, 70 heat exchanger, 71 radiator, 72 oil cooler, 73 CAC, 331 frame, 332 cab, 332H recess, 333 engine compartment, 334 counterweight, 334F front, 335 space, 337, 338 vertical plate.

Claims

1. The engine and A cab in which the operator sits, a cooling unit including a heat exchanger through which a fluid to be cooled flows, and a cooling fan that sends outside air to the heat exchanger to cool the fluid to be cooled; The entire cooling unit is disposed rearward of the cab, A work machine, wherein the cooling unit has a portion located rearward of the engine.

2. The work machine according to claim 1 , wherein a center of rotation of the cooling fan is disposed rearward of an output shaft of the engine.

3. the cooling unit includes a plurality of the cooling fans, The work machine according to claim 2 , wherein the centers of rotation of all of the plurality of cooling fans are disposed rearward of the output shaft of the engine.

4. The work machine according to any one of claims 1 to 3, wherein the cooling fan is an electric fan.

5. The work machine according to any one of claims 1 to 3, wherein the cooling unit faces a rear surface of the cab.

6. The work machine according to any one of claims 1 to 3, wherein the cooling unit is disposed to the left of the engine.

7. a counterweight disposed at a rear end of the work machine; The work machine according to any one of claims 1 to 3, wherein a space serving as an air passage is formed between the engine and the counterweight.

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