Work machine

Abstract

To provide a work machine capable of suppressing performance reduction of an alternator.SOLUTION: A work machine is provided with: heat-exchangers 71, 72, 73 inside which fluid to be cooled is circulated; a plurality of cooling fans 61, 62 that cool the fluid to be cooled by sending fresh air to the heat-exchangers 71, 72, 73; and an alternator 44 generating power through rotation. The heat-exchangers 71, 72, 73 include: inlets 71A, 72A, 73A that serve as inflow ports through which the fluid to be cooled flows into the heat-exchangers 71, 72, 73; and outlets 71B, 72B, 73B that serve as outflow ports through which the fluid to be cooled flows out from the heat-exchangers 71, 72, 73. A rotation center 44C of the alternator 44 is placed at a position closer to the outlets 71B, 72B, 73B than to the inlets 71A, 72A, 73A.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a working machine.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2001-193101 (Patent Document 1) discloses a configuration in which an alternator is provided in an engine, the alternator is rotationally driven by the engine, and an alternator cooling device is provided in the alternator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the alternator is affected by the heat generated from the engine, the power generation amount of the alternator decreases, leading to a deterioration in the performance of the alternator.

[0005] In the present disclosure, a working machine is proposed that can suppress a decrease in the performance of the alternator.

Means for Solving the Problems

[0006] According to an aspect of the present disclosure, there is proposed a working machine including a heat exchanger through which a fluid to be cooled flows inside, a plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled, and an alternator that generates electricity by rotating. The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger. The rotation center of the alternator is disposed closer to the outlet than to the inlet.

[0007] According to an aspect of the present disclosure, a working machine is proposed that includes a heat exchanger through which a fluid to be cooled flows inside, a plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled, and an alternator that generates electricity by rotating. The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger. The plurality of cooling fans includes a first cooling fan disposed closest to the outlet. The rotation center of the alternator is disposed at a position overlapping the first cooling fan in the direction from the inlet to the outlet.

[0008] According to an aspect of the present disclosure, a working machine is proposed that includes a heat exchanger through which a fluid to be cooled flows inside, a plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled, and an alternator that generates electricity by rotating. The plurality of cooling fans includes a first cooling fan disposed on the most downstream side in the flow direction of the fluid to be cooled. The rotation center of the alternator is disposed at a position overlapping the first cooling fan in the flow direction of the fluid to be cooled.

Advantages of the Invention

[0009] According to the working machine of the present disclosure, it is possible to suppress a decrease in the performance of the alternator.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiment for Carrying Out the Invention

[0011] Hereinafter, 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, for convenience of explanation, the configuration may be omitted or simplified in some cases. It is also initially planned that any configurations are extracted from the embodiments and arbitrarily combined.

[0012] <Overall Configuration> In the embodiment, a hydraulic excavator 1 will be described as an example of a working machine. FIG. 1 is a side view schematically showing the configuration of the hydraulic excavator 1.

[0013] As shown in FIG. 1, the hydraulic excavator 1 includes a working machine 2 and a vehicle body 3. The vehicle body 3 includes a traveling body 31, a swing circle 32, a revolving body 33, and a swing motor 35.

[0014] The traveling body 31 has a pair of left and right crawler devices 311. Each of the pair of left and right crawler devices 311 has a traveling motor 312 and a crawler. The hydraulic excavator 1 travels by rotationally driving the pair of left and right crawlers by the traveling motor 312.

[0015] The swing circle 32 is connected to the swing motor 35. The swing circle 32 rotates by the rotational drive of the swing motor 35. The traveling 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).

[0016] The revolving body 33 is installed on the traveling body 31 via the swing circle 32. The revolving body 33 revolves with respect to the traveling body 31 as the swing circle 32 rotates.

[0017] The revolving body 33 has a frame 331 to which the work implement 2 is attached, a cab 332, and an engine room 333. The cab 332 is disposed, for example, on the front left side (front side of the vehicle) of the revolving body 33. The engine room 333 is disposed at the rear part (rear side of the vehicle) of the revolving body 33.

[0018] The work implement 2 is supported by the frame 331 on the front side of the revolving body 33 and, 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, and the like. The bucket 23 is an example of an attachment that can be attached to the tip of the work implement 2.

[0019] In this embodiment, the positional relationship of each part of the hydraulic excavator 1 will be described with reference to the work implement 2.

[0020] The boom 21 of the work implement 2 rotates with respect to the revolving body 33 about a boom foot pin provided at the base end portion of the boom 21. A specific portion of the boom 21 that rotates with respect to the revolving body 33, for example, the tip portion of the boom 21, moves along an arc, and a plane including the arc is specified. When the hydraulic excavator 1 is viewed in plan view, the plane is represented as a straight line. The extending direction of this straight line is the longitudinal direction of the vehicle body 3 of the hydraulic excavator 1 or the longitudinal direction of the revolving body 33, and is hereinafter simply referred to as the longitudinal direction. The left - right direction (vehicle width direction) of the vehicle body 3 of the hydraulic excavator 1 or the left - right direction of the revolving body 33 is a direction orthogonal to the longitudinal direction in plan view, and is hereinafter simply referred to as the left - right direction.

[0021] In the longitudinal 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 in the front direction, the right side and the left side in the left - right direction are the right direction and the left direction, respectively.

[0022] The front-rear direction is the front-rear direction of the operator sitting on the driver's seat in the cab 332. The direction facing the operator sitting on the driver's seat is the front direction, and the direction behind the operator sitting on the driver's seat is the rear direction. The left-right direction is the left-right direction of the operator sitting on the driver's seat. When the operator sitting on the driver's seat faces forward, the right side and the left side are the right direction and the left direction respectively.

[0023] In FIG. 1 and the following drawings, the front-rear direction is indicated by arrow X in the drawing, the left-right direction is indicated by arrow Y in the drawing, and the up-down direction is indicated by arrow Z in the drawing.

[0024] The boom 21 is attached to the slewing body 33. The base end portion of the boom 21 is rotatably connected to the slewing body 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. By this drive, the boom 21 can rotate in the up-down direction with respect to the slewing body 33 around the boom foot pin.

[0025] The arm 22 is attached to the tip of the boom 21. The base end portion of the arm 22 is rotatably connected to the tip portion 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. By this drive, the arm 22 can rotate in the up-down direction with respect to the boom 21 around the boom tip pin 242.

[0026] The bucket 23 is attached to the tip of the arm 22. The bucket 23 is rotatably connected to the tip portion 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. By this drive, the bucket 23 can rotate in the up-down direction with respect to the arm 22 around the arm tip pin 243. Thus, the working machine 2 can be driven.

[0027] <System Configuration> Figure 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 room 333 (Figure 1). The engine 40 is arranged at the center of the engine room 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, for example, a diesel engine. The rotational 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 the fuel injection pump of the engine 40.

[0028] The output shaft 41 of the engine 40 is connected to a power take-off unit 43. Through the power take-off unit 43, the driving force generated by the engine 40 is transmitted to a hydraulic pump 45. The hydraulic pump 45 is driven by the engine 40. The hydraulic pump 45 sucks and discharges the hydraulic oil stored in a hydraulic oil tank 46.

[0029] The hydraulic oil discharged from the hydraulic pump 45 is supplied to various hydraulic actuators via a main valve 47. The hydraulic actuators include a boom cylinder 211, an arm cylinder 221, a bucket cylinder 231, a swing motor 35, and a travel motor 312 shown in Figure 1 as well. The engine 40 is a drive source for the operation of the working machine 2, the swing of the swing body 33, and the travel of the traveling body 31.

[0030] By controlling the supply and discharge of the hydraulic oil to and from the hydraulic actuators, the operation of the hydraulic excavator 1 is controlled. The hydraulic oil is the oil supplied to the hydraulic actuator to operate the hydraulic actuator. The hydraulic oil discharged from the hydraulic actuator is returned to the hydraulic oil tank 46 via the main valve 47.

[0031] An alternator 44 is connected to the power take-off unit 43. The alternator 44 operates as a generator. The alternator 44 generates electricity by rotating upon receiving the driving force generated by the engine 40. The rotation speed of the alternator 44 is set according to 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 power generation amount of the alternator 44.

[0032] 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 a power storage device for storing electric power. The battery 50 is a secondary battery such as a nickel-metal hydride battery or a lithium-hydrogen battery.

[0033] The hydraulic excavator 1 includes a cooling device 60. The cooling device 60 is housed in the engine room 333. The cooling device 60 is disposed to the left of the engine 40. The cooling device 60 is disposed on the left side in the engine room 333. The cooling device 60 is disposed closer to the left side surface of the revolving body 33 than the engine 40. The cooling device 60 of the embodiment includes a heat exchanger 70. The heat exchanger 70 of the embodiment has a radiator 71, an oil cooler 72, and a CAC (Charge Air Cooler) 73.

[0034] The cooling water of the engine 40 flows inside the radiator 71. The cooling water of the engine 40 is the fluid to be cooled by the radiator 71. The 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. The 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.

[0035] The cooling device 60 includes a plurality of cooling fans including a cooling fan 61 and a cooling fan 62. The cooling fans 61 and 62 are respectively disposed facing the heat exchanger 70.

[0036] The cooling fans 61 and 62 take in outside air from the left ventilation opening formed on the left side surface of the rotating body 33 into the engine chamber 333 and send the outside air to the heat exchanger 70. The air flow generated by the cooling fans 61 and 62 cools the fluid to be cooled flowing through the heat exchanger 70. In the heat exchanger 70, the fluid to be cooled exchanges heat with the outside air and releases heat from the fluid to be cooled to the outside air, thereby cooling the fluid to be cooled.

[0037] 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.

[0038] The electric power stored in the battery 50 or the electric power generated by the alternator 44 is supplied to the electric motors 64 and 65, and the electric motors 64 and 65 are driven. The cooling fans 61 and 62 are driven by the power supply from the battery 50 or the alternator 44 to generate an air flow passing through the heat exchanger 70. When the fluid to be cooled passes through the heat exchanger 70, the fluid to be cooled is cooled by releasing heat to the air.

[0039] The hydraulic excavator 1 further includes a controller 80. The controller 80 is a controller that controls the overall operation of the hydraulic excavator 1 and is configured to include a CPU (Central Processing Unit), a non-volatile memory, a timer, and the like. The controller 80 can transmit a control signal to the electric motors 64 and 65. Programs for controlling the cooling fans 61 and 62 and various data necessary for the execution of the programs are stored in the controller 80 in advance.

[0040] The controller 80 of the embodiment is mounted on the hydraulic excavator 1. The controller 80 may not be mounted on the hydraulic excavator 1. The controller 80 may be arranged outside the hydraulic excavator 1. The controller 80 may be arranged at the work site of the hydraulic excavator 1, or may be arranged at a remote location away from the work site of the hydraulic excavator 1. The hydraulic excavator 1 and the controller 80 arranged outside the hydraulic excavator 1 may constitute the control system of the hydraulic excavator 1.

[0041] The controller 80 transmits a motor control signal SM1 to the electric motor 64 to control the rotation direction and rotation speed of the cooling fan 61. The controller 80 transmits a motor control signal SM2 to the electric motor 65 to control the rotation direction and rotation speed of the cooling fan 62.

[0042] <Arrangement of the cooling device 60> The arrangement of the cooling device 60 will be described. FIG. 3 is a schematic diagram showing the arrangement of the devices in the engine room 333 as viewed from the rear. FIG. 4 is a schematic diagram showing the arrangement of the devices in the engine room 333 as viewed from the left side. FIG. 5 is a schematic diagram showing the arrangement of the devices in the engine room 333 as viewed from above.

[0043] In the engine room 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. Among the cooling fan 61 and the cooling fan 62, the cooling fan 61 is arranged below and the cooling fan 62 is arranged above. In the cooling device 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. The cooling fan 61 corresponds to an example of the "first cooling fan". The cooling fan 62 corresponds to an example of the "second cooling fan".

[0044] The cooling fan 62 and the cooling fan 61 are arranged side by side in this order from top to bottom in the vertical direction. The cooling fan 61 is the fan arranged at the bottom among the plurality of cooling fans. The cooling fan 62 is the second fan from the bottom among the plurality of cooling fans.

[0045] The cooling fan 61 rotates about the rotation center 61C to generate an air flow. The cooling fan 62 rotates about the rotation center 62C to generate an air flow. The rotation center 61C of the cooling fan 61 and the rotation center 62C of the cooling fan 62 are arranged side by side in the vertical direction and are arranged at the same position in the front-rear direction indicated by the arrow X in the figure.

[0046] In the engine compartment 333, the radiator 71, the CAC 73, and the oil cooler 72 are arranged side by side in the front-rear direction. From the front to the rear, the radiator 71, the CAC 73, and the oil cooler 72 are arranged in this order. In the left-right direction indicated by the arrow Y in the figure, the cooling fan 61 and the cooling fan 62 are arranged between the heat exchanger 70 (the radiator 71, the CAC 73, and the oil cooler 72) and the engine 40. The cooling fans 61, 62 are adjacent to the heat exchanger 70 in the left-right direction and are arranged on the right side of the heat exchanger 70. The cooling fans 61, 62 face the heat exchanger 70.

[0047] The cooling fan 61 and the cooling fan 62 are arranged to the left of the engine 40. The engine 40 has a left side surface 40L facing left, and the cooling fan 61 and the cooling fan 62 face the left side surface 40L of the engine 40. The cooling fan 61 and the cooling fan 62 are arranged to the right of the heat exchanger 70. A hydraulic pump 45 is arranged to the right of the engine 40. The engine 40 has a right side surface 40R facing right, and the hydraulic pump 45 faces the right side surface 40R of the engine 40.

[0048] The radiator 71 includes an inlet 71A that serves as an inlet through which the cooling water of the engine 40 flows into the radiator 71, an outlet 71B that serves as an outlet through which the cooling water of the engine 40 flows out of the radiator 71, and a cooling core 71C including a plurality of heat exchange tubes. The inlet 71A is disposed at the upper part of the radiator 71. The outlet 71B is disposed at the lower part of the radiator 71. The plurality of heat exchange tubes of the cooling core 71C form a flow path for the cooling water of the engine 40 from the inlet 71A toward the outlet 71B. The flow direction of the cooling water of the engine 40 within the radiator 71 is downward. The cooling water of the engine 40 flowing within the radiator 71 forms a downward flow from top to bottom. The radiator 71 is structured such that the cooling water of the engine 40 enters from the top and exits from the bottom.

[0049] The cooling fan 61 is the cooling fan that is disposed closest to the outlet 71B among the plurality of cooling fans. The cooling fan 62 is disposed closer to the inlet 71A than the cooling fan 61. The cooling fan 61 is the cooling fan that is disposed on the most downstream side in the flow direction of the cooling water within the radiator 71 among the plurality of cooling fans. The cooling fan 62 is disposed on the upstream side of the cooling fan 61 in the flow direction of the cooling water of the engine 40 flowing through the inside of the cooling core 71C. The cooling fan 62 and the cooling fan 61 are arranged side by side in this order in the flow direction of the cooling water of the engine 40 from the inlet 71A toward the outlet 71B.

[0050] The oil cooler 72 includes an inlet 72A that serves as an inlet through which the hydraulic oil flows into the oil cooler 72, an outlet 72B that serves as an outlet through which the hydraulic oil flows out of the oil cooler 72, and a cooling core 72C including a plurality of heat exchange tubes. The inlet 72A is disposed at the upper part of the oil cooler 72. The outlet 72B is disposed at the lower part of the oil cooler 72. The plurality of heat exchange tubes of the cooling core 72C form a flow path for the hydraulic oil from the inlet 72A toward the outlet 72B. The flow direction of the 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 structured such that the hydraulic oil enters from the top and exits from the bottom.

[0051] The cooling fan 61 is the cooling fan among the plurality of cooling fans that is arranged closest to the outlet 72B. The cooling fan 62 is arranged closer to the inlet 72A than the cooling fan 61. The cooling fan 61 is the cooling fan among the plurality of cooling fans that is arranged on the most downstream side in the flow direction of the hydraulic oil in the oil cooler 72. The cooling fan 62 is arranged upstream of the cooling fan 61 in the flow direction of the hydraulic oil flowing through the inside of the cooling core 72C. The cooling fan 62 and the cooling fan 61 are arranged side by side in this order in the flow direction of the hydraulic oil from the inlet 72A to the outlet 72B.

[0052] The CAC 73 includes an inlet 73A serving as an inlet through which air supplied to the engine 40 flows into the CAC 73, an outlet 73B serving as an outlet from which the air flows out of the CAC 73, and a cooling core 73C including a plurality of heat exchange tubes. The inlet 73A is arranged at the upper part of the CAC 73. The outlet 73B is arranged at the lower part of the CAC 73. The plurality of heat exchange tubes of the cooling core 73C form a flow path for the air from the inlet 73A to the outlet 73B. The flow direction of the air in the CAC 73 is downward. The air flowing through the CAC 73 forms a downward flow from top to bottom. The CAC 73 has a structure in which air enters from above and exits from below.

[0053] The cooling fan 61 is the cooling fan among the plurality of cooling fans that is arranged closest to the outlet 73B. The cooling fan 62 is arranged closer to the inlet 73A than the cooling fan 61. The cooling fan 61 is the cooling fan among the plurality of cooling fans that is arranged on the most downstream side in the flow direction of the air in the CAC 73. The cooling fan 62 is arranged upstream of the cooling fan 61 in the flow direction of the air flowing through the inside of the cooling core 73C. The cooling fan 62 and the cooling fan 61 are arranged side by side in this order in the flow direction of the air from the inlet 73A to the outlet 73B.

[0054] The cooling fans 61 and 62 send outside air to all of the cooling core 71C of the radiator 71, the cooling core 72C of the oil cooler 72, and the cooling core 73C of the CAC 73. The flow direction of the cooling water of the engine 40 flowing through the cooling core 71C is downward, the flow direction of the hydraulic oil flowing through the cooling core 72C is downward, and the flow direction of the air flowing through the cooling core 73C is downward. Different types of fluids to be cooled flow inside the cooling cores 71C, 72C, and 73C, and the flow directions of the fluids to be cooled are parallel to each other. The flow directions of the fluids to be cooled flowing through the interiors of the cooling cores 71C, 72C, and 73C are the same direction.

[0055] Any one of the cooling core 71C of the radiator 71, the cooling core 72C of the oil cooler 72, and the cooling core 73C of the CAC 73 corresponds to an example of the "first cooling core". Any other one of the cooling core 71C of the radiator 71, the cooling core 72C of the oil cooler 72, and the cooling core 73C of the CAC 73 corresponds to an example of the "second cooling core".

[0056] <Arrangement of the alternator 44> Next, the arrangement of the alternator 44 with respect to the cooling device 60 will be described. The alternator 44 generates electricity by rotating about the rotation center 44C using the rotation of the engine 40 as a power source. The main direction of the flow direction of the outside air generated by the cooling fans 61 and 62 is the left-right direction, and in FIG. 4, it is the direction perpendicular to the paper surface. The rotation center 44C of the alternator 44 is arranged at a position overlapping with the heat exchanger 70 in the flow direction of the outside air. More specifically, the rotation center 44C of the alternator 44 is arranged at a position overlapping with the cooling core 71C of the radiator 71 in the flow direction of the outside air.

[0057] The alternator 44 is disposed at a position closer to the left side surface 40L than the right side surface 40R of the engine 40 in the left - right direction. Typically, the alternator 44 is exposed on the left side surface 40L of the engine 40. When trying to view the engine 40 from the left, the alternator 44 is arranged in a visible position. The alternator 44 is exposed to the left without being blocked by the engine 40. The alternator 44 is disposed at a position closer to the lower surface than the upper surface of the engine 40 in the up - down direction. The rotation center 44C of the alternator 44 is disposed at a position lower than half of the up - down position of the engine 40. There is no obstacle between the cooling fan 61 and the alternator 44, and the alternator 44 is arranged such that the air flow from the cooling fan 61 can directly hit it.

[0058] The rotation center 44C of the alternator 44 is disposed closer to the outlet 71B of the radiator 71 than the inlet 71A of the radiator 71. The rotation center 44C of the alternator is disposed at a position overlapping the cooling fan 61 in the up - down direction from the inlet 71A to the outlet 71B. The rotation center 44C of the alternator 44 is disposed at a position overlapping the cooling fan 61 in the up - down direction in which the cooling water of the engine 40 flows through the radiator 71.

[0059] The rotation center 44C of the alternator 44 is disposed closer to the outlet 72B of the oil cooler 72 than the inlet 72A of the oil cooler 72. The rotation center 44C of the alternator is disposed at a position overlapping the cooling fan 61 in the up - down direction from the inlet 72A to the outlet 72B. The rotation center 44C of the alternator 44 is disposed at a position overlapping the cooling fan 61 in the up - down direction in which the hydraulic oil flows through the oil cooler 72.

[0060] The rotation center 44C of the alternator 44 is arranged closer to the outlet 73B of the CAC 73 than the inlet 73A of the CAC 73. The rotation center 44C of the alternator is arranged at a position overlapping with the cooling fan 61 in the vertical direction from the inlet 73A to the outlet 73B. The rotation center 44C of the alternator 44 is arranged at a position overlapping with the cooling fan 61 in the vertical direction in which air flows through the CAC 73.

[0061] As shown in FIG. 4, the upper end FU indicates the position in the vertical direction of the upper ends of a plurality of cooling fan groups including the cooling fans 61 and 62. The lower end FL indicates the position in the vertical direction of the lower ends of a plurality of cooling fan groups including the cooling fans 61 and 62. The intermediate position FM indicates the position at half of the distance between the upper end FU and the lower end FL in the vertical direction. The intermediate position FM indicates the position at half of the vertical direction of the cooling fans 61 and 62 arranged vertically. The intermediate position FM indicates the position at half of the vertical direction of a plurality of cooling fan groups including the cooling fans 61 and 62.

[0062] The rotation center 44C of the alternator 44 is arranged at a position lower than the intermediate position FM. The alternator 44 is arranged at a position lower than the intermediate position FM. The rotation center 44C of the alternator 44 is arranged at a position lower than half of the vertical direction in which the cooling fans 61 and 62 are arranged.

[0063] Among the cooling fans 61 and 62 arranged vertically, the upper cooling fan 62 is arranged above the alternator 44. The alternator 44 is arranged at a position facing the lower cooling fan 61. When viewed in the left-right direction, the alternator 44 has a portion overlapping with the lower cooling fan 61. The alternator 44 is arranged at a position lower than the upper cooling fan 62. The upper cooling fan 62 is arranged at a position not facing the alternator 44. The exhaust heat of the upper cooling fan 62 is arranged not to directly hit the alternator 44.

[0064] As shown in FIG. 4, the upper end HxU indicates the position in the vertical direction of the upper end of the heat exchanger 70. The lower end HxL indicates the position in the vertical direction of the lower end of the heat exchanger 70. The intermediate position HxM indicates the position at half the distance between the upper end HxU and the lower end HxL in the vertical direction. The intermediate position HxM indicates the mid-position in the vertical direction of the heat exchanger 70. The rotation center 44C of the alternator 44 is arranged at a position lower than the intermediate position HxM. The alternator 44 is arranged at a position lower than the intermediate position HxM. The alternator 44 is arranged at a position lower than the mid-position in the vertical direction of the heat exchanger 70.

[0065] <Rotation speed control of the cooling fans 61, 62> FIG. 6 is a schematic diagram showing an example of the set values of the rotation speeds of the cooling fans 61, 62. As described with reference to FIG. 2, the controller 80 can control the rotation speeds of the cooling fans 61, 62. The controller 80 can make the rotation speed of the cooling fan 61 equal to the rotation speed of the cooling fan 62, and can also make the rotation speed of the cooling fan 61 different from the rotation speed of the cooling fan 62.

[0066] When making the rotation speed of the cooling fan 61 different from the rotation speed of the cooling fan 62, as shown in FIG. 6, the controller 80 increases the rotation speed of the cooling fan 62 more than the rotation speed of the cooling fan 61. Among the cooling fans 61, 62, the rotation speed of the cooling fan 62 arranged closer to the inlet of the cooling target fluid to the heat exchanger 70 is set to be greater than the rotation speed of the cooling fan 61 arranged closest to the outlet of the cooling target fluid from the heat exchanger 70. A larger amount of outside air will be supplied to the position where the high-temperature cooling target fluid that has just flowed in from the inlet of the cooling core of the heat exchanger 70 flows. Thereby, since the heat dissipation from the high-temperature cooling target fluid to the outside air is promoted, the cooling target fluid is efficiently cooled.

[0067] <Function and effect> Although there is also a description that partially overlaps with the above description, when summarizing the characteristic configurations and the functions and effects of the working machine of the embodiment, they are as follows.

[0068] As shown in FIG. 4, the heat exchanger 70 includes inlets 71A, 72A, 73A serving as inlets through which the fluid to be cooled flows into the heat exchanger 70, and outlets 71B, 72B, 73B serving as outlets through which the fluid to be cooled flows out of the heat exchanger 70. The rotation center 44C of the alternator 44 is disposed closer to the outlets 71B, 72B, 73B than the inlets 71A, 72A, 73A.

[0069] Among the plurality of cooling fans 61, 62, the cooling fan 61 is disposed closest to the outlets 71B, 72B, 73B. The rotation center 44C of the alternator 44 is disposed at a position overlapping the cooling fan 61 in the direction from the inlets 71A, 72A, 73A toward the outlets 71B, 72B, 73B.

[0070] The power generation capacity of the alternator 44 depends on the ambient temperature. The alternator 44 is located downstream of the cooling fans 61, 62. When the alternator 44 receives the exhaust heat of the cooling fans 61, 62, the temperature around the alternator 44 rises, and the power generation amount of the alternator 44 decreases.

[0071] FIG. 7 is a graph showing the relationship between the ambient temperature and the output current of the alternator 44. The horizontal axis in FIG. 7 is the rotation speed of the alternator 44, and the vertical axis is the output current of the alternator 44. In FIG. 7, the variation of the output current with respect to the rotation speed of the alternator 44 at the ambient temperatures T1 and T2 is illustrated. The temperature T2 is higher than the temperature T1. That is, the relationship T2 > T1 holds between the temperature T1 and the temperature T2.

[0072] As shown in FIG. 7, as the rotation speed of the alternator 44 increases, the output current of the alternator 44 increases. When comparing the output currents when the alternator 44 operates at the rotation speed R, the output current is A1 at the ambient temperature T1, and the output current A2 is smaller than A1 at the ambient temperature T2. FIG. 7 proves that when the temperature around the alternator 44 rises, the power generation amount of the alternator 44 decreases, leading to a degradation in the performance of the alternator 44.

[0073] The high-temperature fluid to be cooled flows into the heat exchanger 70 from the inlets 71A, 72A, and 73A. The cooling fans 61 and 62 send outside air to the heat exchanger 70, and the fluid to be cooled is cooled. The fluid to be cooled with a reduced temperature flows out from the outlets 71B, 72B, and 73B. At positions near the outlets 71B, 72B, and 73B of the heat exchanger 70, the fluid to be cooled, which has released heat to the air near the inlets 71A, 72A, and 73A and has a lowered temperature, flows. The temperature of the fluid to be cooled becomes lower as it gets closer to the outlets 71B, 72B, and 73B.

[0074] FIG. 8 is a graph showing the temperature gradient of the heat exchanger 70. FIG. 8 shows a smoothed graph of the results of measuring the temperature of the cooling core 73C of the CAC 73 on the downstream side of the air flow passing through the cooling core 73C in the heat exchanger 70. The horizontal axis of FIG. 8 is the temperature of the cooling core 73C, and the vertical axis is the distance from the upper part of the cooling core 73C. The position where the vertical axis of FIG. 8 intersects the horizontal axis is the upper end of the cooling core 73C, and the farther away from the horizontal axis, the farther away from the upper end of the cooling core 73C and closer to the lower end.

[0075] As shown in FIG. 8, the temperature of the cooling core 73C is the highest at the upper end of the cooling core 73C and gradually decreases from the upper end to the lower end of the cooling core 73C. It is confirmed by FIG. 8 that the temperature of the fluid to be cooled (air) passing through the cooling core 73C is higher the closer it is to the inlet 73A at the upper end of the cooling core 73C and lower the closer it is to the outlet 73B at the lower end of the cooling core 73C. A large amount of heat is released from the cooling core 73C to the air passing near the upper end of the cooling core 73C where the temperature is high. The heat release from the cooling core 73C to the air passing near the lower end of the cooling core 73C where the temperature is low is relatively small.

[0076] The air passing through the heat exchanger 70 near the outlets 71B, 72B, 73B will be at a lower temperature than the air passing through the heat exchanger 70 near the inlets 71A, 72A, 73A. The air passing through the heat exchanger 70 has a temperature gradient such that it is hotter the closer it is to the inlets 71A, 72A, 73A and colder the closer it is to the outlets 71B, 72B, 73B.

[0077] By arranging the alternator 44 near the outlets 71B, 72B, 73B, the air passing through the position where the low-temperature fluid to be cooled flows will flow toward the alternator 44. The temperature of the air flowing toward the alternator 44 is lowered. A colder air flow is generated around the alternator 44. Thereby, the temperature around the alternator 44 can be lowered, so a decrease in the power generation amount of the alternator 44 is suppressed. Therefore, a decrease in the performance of the alternator 44 can be suppressed.

[0078] As shown in FIG. 4, among the plurality of cooling fans 61, 62, the cooling fan 61 is arranged on the most downstream side in the flow direction of the fluid to be cooled in the heat exchanger 70. The rotation center 44C of the alternator 44 is arranged at a position overlapping the cooling fan 61 in the flow direction of the fluid to be cooled.

[0079] The cooling fans 61, 62 send outside air to the heat exchanger 70, and the high-temperature fluid to be cooled flowing into the heat exchanger 70 is cooled. On the downstream side in the flow direction of the fluid to be cooled in the heat exchanger 70, the fluid to be cooled, whose temperature has decreased after dissipating heat to the air on the upstream side, flows. The temperature of the fluid to be cooled decreases as it goes downstream in the flow direction of the fluid to be cooled.

[0080] The air passing through the heat exchanger 70 at a position downstream in the flow direction of the fluid to be cooled will be at a lower temperature than the air passing through the heat exchanger 70 at a position upstream in the flow direction of the fluid to be cooled. The air passing through the heat exchanger 70 has a temperature gradient such that it is hotter the closer it is to the upstream end in the flow direction of the fluid to be cooled and colder the closer it is to the downstream end in the flow direction of the fluid to be cooled.

[0081] By arranging the alternator 44 on the downstream side in the flow direction of the fluid to be cooled, the air that has passed through the position where the low-temperature fluid to be cooled flows will flow from the cooling fan 61 toward the alternator 44. The temperature of the air flowing toward the alternator 44 is lowered. A flow of air with a lower temperature is generated around the alternator 44. Thereby, the temperature around the alternator 44 can be lowered, so that a decrease in the power generation amount of the alternator 44 is suppressed. Therefore, a decrease in the performance of the alternator 44 can be suppressed.

[0082] As shown in FIG. 4, the inlets 71A, 72A, 73A may be arranged at the upper part of the heat exchanger 70, and the outlets 71B, 72B, 73B may be arranged at the lower part of the heat exchanger 70. The flow direction of the fluid to be cooled in the heat exchanger 70 may be downward. By doing so, the air that has passed through the heat exchanger 70 will have a temperature gradient in which the temperature gradually decreases from top to bottom.

[0083] At this time, the alternator 44 will be arranged such that the rotation center 44C is close to the lower part of the heat exchanger 70 and at a low position. The alternator 44 is arranged at a position facing the lower part of the heat exchanger 70. The alternator 44 is arranged at a position facing the lower cooling fan 61 among the vertically arranged cooling fans 61, 62.

[0084] Since the air with a high temperature has a small specific gravity, it flows upward. The air that has been heated by radiating heat from the high-temperature fluid to be cooled at the upper part of the heat exchanger 70 and whose temperature has risen is suppressed from flowing downward toward the alternator 44. Thereby, the temperature around the alternator 44 can be lowered, so that a decrease in the power generation amount of the alternator 44 is suppressed. Therefore, a decrease in the performance of the alternator 44 can be suppressed.

[0085] As shown in FIG. 6, the controller 80 may increase the rotation speed of the cooling fan 62 rather than the rotation speed of the cooling fan 61. The cooling fan 62 is disposed near the inlet of the heat exchanger 70 and on the upstream side of the fluid to be cooled. A hotter fluid to be cooled flows at a position through which the air flow generated by the cooling fan 62 passes.

[0086] When setting the rotation speeds of the cooling fans 61 and 62 to be different, the rotation speed of the cooling fan 62 is set to be greater than the rotation speed of the cooling fan 61. By increasing the flow rate of the air flow generated by the cooling fan 62, heat dissipation to the air flow generated by the cooling fan 62 promotes a temperature drop of the fluid to be cooled. The air that has passed through the position where the fluid to be cooled at a lower temperature flows flows to the alternator 44. Thereby, the temperature around the alternator 44 can be lowered, so that a decrease in the power generation amount of the alternator 44 is suppressed. Therefore, a performance degradation of the alternator 44 can be suppressed.

[0087] As shown in FIG. 4, a configuration may be adopted in which the cooling fan 61 sends outside air to the three cooling cores 71C, 72C, and 73C, and the cooling fan 62 sends outside air to the three cooling cores 71C, 72C, and 73C. Thereby, the fluid to be cooled flowing through each of the interiors of the three cooling cores 71C, 72C, and 73C can be efficiently cooled by heat dissipation to the air flows generated by the cooling fans 61 and 62.

[0088] As shown in FIG. 4, the flow directions of the fluids to be cooled flowing through the interiors of the three cooling cores 71C, 72C, and 73C may be the same. By making the flow of the fluid to be cooled flowing through the heat exchanger 70 one-way, a temperature gradient is surely created in the air that has passed through the heat exchanger, and air at a lower temperature can be made to flow toward the alternator 44.

[0089] As shown in FIG. 2, the cooling fans 61 and 62 may be electric fans driven by electric motors 64 and 65. The electric power generated by the alternator 44 may be supplied to the electric motors 64 and 65. If the cooling fans 61 and 62 are electric fans, the arrangement is not limited by the position of the output shaft 41 of the engine 40, and the degree of freedom in arranging the cooling fans 61 and 62 can be improved. The cooling fans 61 and 62 can be arranged at desired positions with respect to the alternator 44, and air with a low temperature can be reliably flowed toward the alternator 44. A decrease in the power generation amount of the alternator 44 is suppressed. As a result, it is possible to avoid the decrease in the power generation amount of the alternator 44 from affecting the rotation speed of the cooling fans 61 and 62 themselves.

[0090] In the embodiment, the hydraulic excavator 1 has been described as an example of the working machine. However, the idea of the present disclosure may be applied not only to the hydraulic excavator 1 but also to other types of working machines such as wheel loaders and bulldozers.

[0091] <Appendix> The above description includes the features appended below.

[0092] (Appendix 1) A heat exchanger through which a fluid to be cooled flows inside; A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled; An alternator that generates electricity by rotating, and The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger, A working machine in which the rotation center of the alternator is arranged closer to the outlet than the inlet.

[0093] (Appendix 2) A heat exchanger through which a fluid to be cooled flows inside; A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled; An alternator that generates electricity by rotating, and The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger. The plurality of cooling fans includes a first cooling fan disposed closest to the outlet. The working machine, wherein a rotation center of the alternator is disposed at a position overlapping with the first cooling fan in a direction from the inlet to the outlet.

[0094] (Supplementary Note 3) The plurality of cooling fans includes a second cooling fan disposed closer to the inlet than the first cooling fan. The working machine further includes a controller that controls the first cooling fan and the second cooling fan. The working machine according to Supplementary Note 2, wherein the controller increases the rotational speed of the second cooling fan more than the rotational speed of the first cooling fan.

[0095] (Supplementary Note 4) The inlet is disposed at an upper portion of the heat exchanger. The working machine according to any one of Supplementary Notes 1 to 3, wherein the outlet is disposed at a lower portion of the heat exchanger.

[0096] (Supplementary Note 5) A heat exchanger through which a fluid to be cooled flows inside, A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled, An alternator that generates electricity by rotating, and The plurality of cooling fans includes a first cooling fan disposed on the most downstream side in a flow direction of the fluid to be cooled. The working machine, wherein a rotation center of the alternator is disposed at a position overlapping with the first cooling fan in the flow direction of the fluid to be cooled.

[0097] (Supplementary Note 6) The working machine according to Supplementary Note 5, wherein the flow direction of the fluid to be cooled is downward.

[0098] (Appendix 7) The plurality of cooling fans includes a second cooling fan disposed upstream of the first cooling fan in the flow direction of the fluid to be cooled. The working machine further includes a controller that controls the first cooling fan and the second cooling fan. The controller increases the rotational speed of the second cooling fan compared to the rotational speed of the first cooling fan. The working machine according to Appendix 5 or Appendix 6.

[0099] (Appendix 8) The heat exchanger includes a first cooling core and a second cooling core. A first fluid to be cooled flows through the inside of the first cooling core, and a second fluid to be cooled different from the first fluid to be cooled flows through the inside of the second cooling core. The plurality of cooling fans send outside air to both the first cooling core and the second cooling core. The working machine according to any one of Appendices 1 to 7.

[0100] (Appendix 9) The flow direction of the first fluid to be cooled and the flow direction of the second fluid to be cooled are the same direction. The working machine according to Appendix 8.

[0101] (Appendix 10) The flow direction of the first fluid to be cooled is downward, and the flow direction of the second fluid to be cooled is downward. The working machine according to Appendix 9.

[0102] (Appendix 11) The plurality of cooling fans are electric fans. The working machine according to any one of Appendices 1 to 10.

[0103] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Description of Symbols

[0104] 1 Hydraulic excavator, 2 Working machine, 3 Vehicle body, 21 Boom, 22 Arm, 23 Bucket, 31 Travel unit, 33 Swing body, 35 Swing motor, 40 Engine, 40L Left side, 40R Right side, 41 Output shaft, 44 Alternator, 44C, 61C, 62C Rotation center, 45 Hydraulic pump, 50 Battery, 60 Cooling device, 61, 62 Cooling fan, 64, 65 Electric motor, 70 Heat exchanger, 71 Radiator, 71A, 72A, 73A Inlet, 71B, 72B, 73B Outlet, 71C, 72C, 73C Cooling core, 72 Oil cooler, 73 CAC, 80 Controller, 333 Engine room, FL, HxL Lower end, FU, HxU Upper end, FM, HxM Intermediate position.

Claims

1. A heat exchanger through which a fluid to be cooled flows inside; A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled; An alternator that generates electricity by rotating, and The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger, A work machine, wherein the rotation center of the alternator is disposed closer to the outlet than the inlet.

2. A heat exchanger through which a fluid to be cooled flows inside; A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled; An alternator that generates electricity by rotating, and The heat exchanger includes an inlet through which the fluid to be cooled flows into the heat exchanger and an outlet through which the fluid to be cooled flows out of the heat exchanger, The plurality of cooling fans includes a first cooling fan disposed closest to the outlet, A work machine, wherein the rotation center of the alternator is disposed at a position overlapping the first cooling fan in a direction from the inlet to the outlet.

3. The plurality of cooling fans includes a second cooling fan disposed closer to the inlet than the first cooling fan, The work machine further includes a controller that controls the first cooling fan and the second cooling fan, The work machine according to claim 2, wherein the controller increases the rotation speed of the second cooling fan more than the rotation speed of the first cooling fan.

4. The inlet is disposed at an upper portion of the heat exchanger, The work machine according to claim 1 or claim 2, wherein the outlet is disposed at a lower portion of the heat exchanger.

5. A heat exchanger through which a fluid to be cooled flows inside; A plurality of cooling fans that send outside air to the heat exchanger to cool the fluid to be cooled; An alternator that generates electricity by rotating, and The plurality of cooling fans includes a first cooling fan disposed on the most downstream side in the flow direction of the fluid to be cooled, A work machine, wherein the rotation center of the alternator is disposed at a position overlapping the first cooling fan in the flow direction of the fluid to be cooled.

6. The work machine according to claim 5, wherein the flow direction of the fluid to be cooled is downward.

7. The plurality of cooling fans includes a second cooling fan disposed upstream of the first cooling fan in the flow direction of the fluid to be cooled. The working machine further includes a controller that controls the first cooling fan and the second cooling fan. The controller increases the rotational speed of the second cooling fan compared to the rotational speed of the first cooling fan. The working machine according to claim 5 or claim 6.

8. The heat exchanger includes a first cooling core and a second cooling core. A first fluid to be cooled flows through the inside of the first cooling core, and a second fluid to be cooled different from the first fluid to be cooled flows through the inside of the second cooling core. The plurality of cooling fans send outside air to both the first cooling core and the second cooling core. The working machine according to claim 1, claim 2, or claim 5.

9. The flow direction of the first fluid to be cooled and the flow direction of the second fluid to be cooled are the same direction. The working machine according to claim 8.

10. The flow direction of the first fluid to be cooled is downward, and the flow direction of the second fluid to be cooled is downward. The working machine according to claim 9.

11. The plurality of cooling fans are electric fans. The working machine according to claim 1, claim 2, or claim 5.

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