Construction Machinery

Abstract

To provide a construction machine capable of preventing an increase in overall power of a plurality of fans even when there is a restriction in arrangement relations between a plurality of heat exchangers and fans, and required air quantity, etc. are different among the heat exchangers.SOLUTION: In a construction machine, the number of rotations of a plurality of fans 41-46 for supplying cooling air to a plurality of heat exchangers 31-33 arranged in parallel are controlled by a controller 80. The plurality of heat exchangers are classified into a plurality of groups including a specific group having heat exchangers 31 and 32 adjacent to each other. Each fan is associated only with any one of the plurality of groups, and at least one fan is associated with each group. A separation wall 52 is arranged for separating a flow channel from the heat exchanger of each group to the corresponding fan. Two or more fans 41-44 are associated with the specific group, and a first fan 41 of the fans in the specific group is arranged in the border of first to second heat exchangers 31 and 32 adjacent to each other of the specific group. The controller outputs a control command to rotate all the fans in the specific group with the same number of rotations.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a construction machine, and more particularly to a construction machine equipped with a cooling unit that supplies cooling air generated by a plurality of fans to a plurality of heat exchangers such as a radiator and an oil cooler. [Background technology]

[0002] In construction machinery such as hydraulic excavators and hydraulic cranes, it is necessary to prevent overheating by properly discharging heat generated in the engine, hydraulic system, etc. to the outside of the machine. For this reason, construction machinery is equipped with multiple heat exchangers, such as a radiator for water-cooling the engine, an oil cooler for cooling the hydraulic oil circulating in the hydraulic system, and an intercooler for cooling the engine's intake air. Some construction machinery is cooled by supplying cooling air generated by multiple cooling fans to these multiple heat exchangers (see, for example, Patent Document 1).

[0003] The heat exchanger described in Patent Document 1 includes a plurality of heat exchangers arranged in parallel to supply each heat exchanger with the required airflow while reducing fuel consumption and noise, a plurality of air blowing means (fans) arranged facing each heat exchanger, a plurality of electric drive sources for driving each air blowing means (fans), a plurality of temperature detection means for detecting the temperature of fluid passing through each heat exchanger, and a control means for controlling the drive speed of each electric drive source based on the temperature detected by each temperature detection means. In this heat exchanger, the plurality of air blowing means are separated by partition walls arranged inside a shroud (casing), and the partition walls are located at the boundaries between the plurality of heat exchangers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-198135 Summary of the Invention [Problem to be solved by the invention]

[0005] In the heat exchanger described in Patent Document 1, a partition wall inside the shroud prevents each heat exchanger from being affected by air blowers other than the one facing it. In other words, the cooling air generated by the fan or fans constituting each air blower is supplied only to the heat exchanger that the air blower faces, and is not supplied to any other heat exchangers.

[0006] However, when using mass-produced or other off-the-shelf fans as the fans constituting each air blowing means rather than custom-made, dedicated fans, it may be difficult to position the fans facing the heat exchangers depending on the size and shape of the heat exchangers. In other words, there may be restrictions on the relative positions of multiple heat exchangers and multiple fans. Furthermore, the required air volume (heat exchange volume) and suction power may differ significantly between the multiple heat exchangers. In such cases, depending on how the cooling air volume distribution of each fan is set, the overall driving power of the multiple fans may increase.

[0007] The present invention has been made to solve the above problems, and its purpose is to provide a construction machine that can prevent an increase in the overall driving power of multiple fans, even when there are restrictions on the relative arrangement of multiple heat exchangers and multiple fans, and the required air volume (heat exchange volume) and suction force differ significantly between the multiple heat exchangers. [Means for solving the problem]

[0008] The present application includes a plurality of means for solving the above-mentioned problems, and one example thereof is a construction machine comprising: a casing having a peripheral wall; a plurality of heat exchangers arranged in parallel across the peripheral wall; a plurality of fans for supplying cooling air to the plurality of heat exchangers; and a controller for controlling the rotation speed of the plurality of fans, wherein the plurality of heat exchangers are classified into a plurality of groups, and each of the plurality of heat exchangers belongs to only one of the plurality of groups, and each of the plurality of fans is arranged in correspondence with only one of the plurality of groups, and at least one fan is associated with each group of the heat exchangers, and a controller for controlling the rotation speed of the plurality of fans is arranged within a space surrounded by the peripheral wall. a separation wall is arranged so that the flow paths from each group of heat exchangers to the corresponding fans are separated from each other, the plurality of groups includes a specific group consisting of adjacent heat exchangers, two or more fans are associated with the specific group of heat exchangers, a first fan which is one of the two or more fans associated with the specific group of heat exchangers is arranged on the boundary between the first heat exchanger and the second heat exchanger which belong to the specific group and are arranged adjacent to each other, and the controller is configured to output a control command to rotate the first fan and the other fans associated with the specific group of heat exchangers at the same rotation speed. [Effects of the Invention]

[0009] According to the present invention, when a first fan is arranged to supply cooling air to adjacent heat exchangers due to restrictions on the relative arrangement of the heat exchangers and the fans, the rotation speeds of two or more fans, including the first fan associated with a specific group consisting of the adjacent heat exchangers, are controlled by the same rotation speed control command, thereby making the flow velocity distribution in the flow path through which the cooling air generated by the two or more fans, including the first fan of the specific group, flows substantially uniform, thereby reducing loss due to mixing of the cooling air in the specific group. Therefore, even if there are restrictions on the relative arrangement of the heat exchangers and the fans and the required air volume (heat exchange volume) and suction force differ significantly between the multiple heat exchangers, an increase in the driving power of the entire multiple fans can be prevented. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view showing the appearance of a hydraulic excavator as a first embodiment of a construction machine according to the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the hydraulic excavator shown in FIG. 1 as viewed from the arrows II-II, and is a schematic view showing the internal configuration of a machine room of the hydraulic excavator. [Figure 3] 3 is a schematic front view of a cooling unit housed in a machine room of the hydraulic excavator shown in FIG. 2, viewed from the heat exchanger side. [Figure 4] FIG. 4 is a schematic perspective view of the cooling unit shown in FIG. 3, as viewed from the fan side. [Figure 5] FIG. 5 is a schematic perspective view showing the internal structure of the cooling unit shown in FIG. 4 with some parts omitted. [Figure 6] 6 is a schematic cross-sectional view of the cooling unit shown in FIG. 3, as viewed from the arrows VI-VI. [Figure 7] 2 is a block diagram showing the functional configuration of a controller that constitutes a part of the first embodiment of the construction machine of the present invention. FIG. [Figure 8] 8 is a flowchart showing an example of a processing procedure for controlling driving of a fan of a cooling unit by a controller shown in FIG. 7. [Figure 9] FIG. 4 is a block diagram showing the functional configuration of a controller that constitutes a part of a second embodiment of the construction machine of the present invention. [Figure 10] 10 is a flowchart showing an example of a processing procedure for controlling driving of a fan of a cooling unit by a controller shown in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a construction machine according to the present invention will now be described with reference to the accompanying drawings. In the present embodiment, a hydraulic excavator will be taken as an example of the construction machine.

[0012] [First embodiment] First, the schematic configuration of a hydraulic excavator as a first embodiment of a construction machine of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a side view showing the appearance of the hydraulic excavator as the first embodiment of a construction machine of the present invention. Figure 2 is a schematic cross-sectional view of the hydraulic excavator shown in Figure 1 as viewed from the II-II arrows, and is a schematic view showing the internal configuration of the machinery compartment of the hydraulic excavator. Here, the description will be given using front, rear, left, and right directions as seen from an operator seated in the driver's seat.

[0013] In Fig. 1, the hydraulic excavator 1 has a machine body made up of a self-propelled lower traveling body 2 and an upper rotating body 3 rotatably mounted on the lower traveling body 2. The lower traveling body 2 has crawler-type traveling devices 6 on the left and right (only one is shown). The left and right traveling devices 6 are driven by traveling hydraulic motors (not shown) serving as hydraulic actuators. The upper rotating body 3 is configured to rotate relative to the lower traveling body 2 by a swing hydraulic motor (not shown) serving as a hydraulic actuator.

[0014] A front work unit 4 is attached to the front of the upper rotating body 3 so as to be rotatable in the vertical direction. The front work unit 4 is an articulated work device for performing excavation work and the like, and is equipped with a boom 8, an arm 9, and a bucket 10 as a work implement. The base end of the boom 8 is rotatably connected to the front of the upper rotating body 3. The base end of the arm 9 is rotatably connected to the tip of the boom 8. The base end of the bucket 10 is rotatably connected to the tip of the arm 9. The boom 8, arm 9, and bucket 10 are driven by a boom cylinder 11, an arm cylinder 12, and a bucket cylinder 13, which serve as hydraulic actuators, respectively.

[0015] The upper rotating body 3 is configured to include a rotating frame 15 as a support structure rotatably mounted on the lower traveling body 2, a cab 16 installed on the front left side of the rotating frame 15, and a machine room 20 formed on the rear side of the rotating frame 15. The cab 16 is provided with a driver's seat (not shown) where an operator sits, as well as various operating devices (not shown) for operating the lower traveling body 2, the upper rotating body 3, the front work unit 4, etc. Also provided is a key switch 18 (see FIG. 7 described below) located therein.

[0016] As shown in Fig. 2, the machinery room 20 accommodates an engine 23 as a prime mover, a hydraulic pump 24 driven by the engine 23, an exhaust gas aftertreatment device 25 that purifies exhaust gas from the engine 23, and the like. The hydraulic pump 24 constitutes a hydraulic system together with hydraulic actuators such as the boom cylinder 11, arm cylinder 12, bucket cylinder 13 (see Fig. 1), traveling hydraulic motor, and swing hydraulic motor (none of which are shown), and supplies pressurized oil to the hydraulic actuators 11, 12, and 13. The exhaust gas aftertreatment device 25 includes, for example, a PM collector 25a that collects particulate matter (PM) generated by combustion in the engine 23 and a NOx purification device 25b that purifies NOx contained in the exhaust gas from the engine 23. The hydraulic pump 24 and the exhaust gas aftertreatment device 25 are arranged, for example, on one side of the engine 23 (the right side in Fig. 2).

[0017] A cooling unit 26 is disposed in the machinery room 20 on the opposite side (left side in FIG. 2) of the hydraulic pump 24 and the exhaust gas aftertreatment device 25 across the engine 23. The cooling unit 26 dissipates heat generated by driving a hydraulic system including the hydraulic pump 24 and hydraulic actuators 11, 12, 13, etc., and heat generated by driving the engine 23, to the outside of the machinery room 20 by cooling air generated by a cooling fan group 40 (see FIG. 4, described later). The cooling unit 26 is fixed inside the machinery room 20 via a mounting bracket 26a. The detailed configuration of the cooling unit 26 will be described later.

[0018] The outer shell of the machine room 20 is formed by a cover 21 that surrounds various devices such as the engine 23, hydraulic pump 24, exhaust gas aftertreatment device 25, and cooling unit 26. An intake port 21a is provided on a side portion of the cover 21 near the cooling unit 26 to take in outside air into the machine room 20. An exhaust port 21b is provided on a bottom portion of the cover 21 near the engine 23, a bottom portion near the hydraulic pump 24, and a side portion near the exhaust gas aftertreatment device 25 to exhaust the cooling air generated by the cooling unit 26 to the outside of the machine room 20.

[0019] Next, the cooling unit constituting part of the first embodiment of the construction machine of the present invention will be described in detail with reference to Figures 3 to 6. Figure 3 is a schematic front view of the cooling unit housed in the machine room of the hydraulic excavator shown in Figure 2, viewed from the heat exchanger side. Figure 4 is a schematic perspective view of the cooling unit shown in Figure 3, viewed from the fan side. Figure 5 is a schematic perspective view showing the internal structure of the cooling unit shown in Figure 4, with some parts omitted. Figure 6 is a schematic cross-sectional view of the cooling unit shown in Figure 3, viewed from the arrows VI-VI.

[0020] 3 and 4, the cooling unit 26 includes a heat exchanger group 30 made up of three or more heat exchangers, a cooling fan group 40 made up of three or more fans that supply cooling air to the heat exchanger group 30, and a casing 50 that forms a flow path from the heat exchanger group 30 to the cooling fan group 40. That is, as shown in FIGS. 5 and 6, the heat exchanger group 30 is disposed on one side of the flow path formed by the casing 50, and the cooling fan group 40 is disposed on the other side of the flow path formed by the casing 50.

[0021] As shown in FIG. 3, for example, the heat exchanger group 30 is composed of an intercooler (hereinafter sometimes referred to as a first heat exchanger) 31, a radiator (hereinafter sometimes referred to as a second heat exchanger) 32, and an oil cooler (hereinafter sometimes referred to as a third heat exchanger) 33. The intercooler 31 cools the intake air of the engine 23 (see FIG. 2) in order to reduce nitrogen oxides generated during combustion in the engine 23. The intercooler 31 generally requires a smaller amount of heat exchange than the radiator 32 and the oil cooler 33, and is also smaller in size (external dimensions) than the radiator 32 and the oil cooler 33. The radiator 32 cools the coolant for the engine 23. The oil cooler 33 cools the hydraulic oil circulating in a hydraulic circuit composed of the hydraulic actuators 11, 12, and 13 (see FIG. 1), the hydraulic pump 24 (see FIG. 2), etc. The intercooler 31, the radiator 32, and the oil cooler 33 are formed, for example, in rectangular shapes with approximately the same height but different widths, and are located on approximately the same plane. The intercooler 31, the radiator 32, and the oil cooler 33 are arranged in parallel to one another in this order on one side of the casing 50 so as to cross the flow path formed by the casing 50. In other words, the radiator 32 is arranged so as to be sandwiched between the intercooler 31 and the oil cooler 33, adjacent to each other.

[0022] 3 and 4, the cooling fan group 40 is composed of six fans: a first fan 41, a second fan 42, a third fan 43, a fourth fan 44, a fifth fan 45, and a sixth fan 46. The number of fans constituting the cooling fan group 40 is set according to the amount of heat exchange required for the plurality of heat exchangers 31, 32, and 33. Each of the fans 41 to 46 generates cooling air with the heat exchanger group 30 side as the intake side. That is, the cooling fan group 40 draws in outside air from outside the machine room 20, supplies it to the heat exchanger group 30 as cooling air, and then discharges it to the outside of the machine room 20 via the peripheries of the engine 23, the hydraulic pump 24, and the exhaust gas treatment device 25 (see FIG. 2).

[0023] The first fan 41 to the sixth fan 46 are all configured with the same shape and size, as shown in FIG. 4, for example. By making the first fan 41 to the sixth fan 46 all have the same specifications, costs can be reduced. Each of the fans 41 to 46 has an impeller made up of a rotatable rotating shaft 47 and a plurality of blades 48 arranged on the outer periphery of the rotating shaft 47, and a ring (shroud) 49 arranged on the outer periphery of the impeller with a gap. The rotating shaft 47 has an electric motor built in as a drive device, for example. The electric motor is driven using power from an alternator (not shown) attached to the engine 23 (see FIG. 2), for example.

[0024] The first fan 41 to the sixth fan 46 are arranged in parallel with one another, without being positioned upstream or downstream of one another. For example, as shown in FIGS. 3, 5, and 6, the first fan 41 is arranged so as to directly face (oppose) both the first heat exchanger 31 and the second heat exchanger 32 when viewed from one side of the casing 50 to the other (from the front side to the back side in FIG. 3, from the back side to the front side in FIG. 5, and from the bottom side to the top side in FIG. 6). The height direction of the first fan 41 is approximately at the center of the height direction of the first heat exchanger 31 and the second heat exchanger 32. The second fan 42 and the third fan 43 are arranged so as to directly face (oppose) the second heat exchanger 32 and be spaced apart in the vertical direction. 3 and 6, when viewed from one side of the casing 50 to the other (from the front to the back in FIG. 3, and from the bottom to the top in FIG. 6), the fourth fan 44 is disposed in a position overlapping (straddling) both the second heat exchanger 32 and the third heat exchanger 33. The position of the fourth fan 44 in the height direction is approximately the same as that of the first fan 41. The fifth fan 45 and the sixth fan 46 are disposed directly opposite (opposite) the third heat exchanger 33 with a gap therebetween in the vertical direction.

[0025] The first fan 41 is configured, by its arrangement and the structure of the casing 50 (including the second partition wall 53 described below), to supply cooling air to both the intercooler 31 and the radiator 32. The second to fourth fans 42 to 44 are configured, by their arrangement and the structure of the casing 50 (including the first partition wall 52 and the second partition wall 53 described below), to supply cooling air mainly to the radiator 32. The fifth fan 45 and the sixth fan 46 are configured, for example, as shown in FIGS. 3 to 5, to supply cooling air only to the oil cooler 33 by their arrangement and the structure of the casing 50 (including the first partition wall 52 described below).

[0026] As shown in Figures 3, 5, and 6, the casing 50 has a rectangular cylindrical peripheral wall 51 extending in one direction (vertical direction in Figure 6), and a first partition wall 52 and a second partition wall 53 extending from the heat exchanger group 30 side (lower side in Figure 6) to the cooling fan group 40 side (upper side in Figure 6) within the space surrounded by the peripheral wall 51 and arranged in the arrangement direction of the parallel heat exchangers 31, 32, 33 (transverse direction of the peripheral wall 51).

[0027] The peripheral wall 51 is composed of a first side surface portion 55 on the left side and a second side surface portion 56 on the right side when viewed from one side in the extension direction (the heat exchanger group 30 side), a lower surface portion 57 connecting the lower end of the first side surface portion 55 to the lower end of the second side surface portion 56, and an upper surface portion 58 connecting the upper end of the first side surface portion 55 to the upper end of the second side surface portion 56. The space surrounded by the peripheral wall 51 functions as a flow path through which cooling air from the cooling fan group 40 flows. In this embodiment, the peripheral wall 51 is formed in a rectangular cylindrical shape. However, as long as the peripheral wall 51 is cylindrical, the cross-sectional shape in the extension direction can be any shape, such as a polygon.

[0028] 5 and 6 , the first partition wall 52 and the second partition wall 53 of the casing 50 divide the space formed by the peripheral wall 51 from the heat exchanger group 30 to the cooling fan group 40. That is, by dividing the space surrounded by the peripheral wall 51 with the first partition wall 52 and the second partition wall 53, a first space 61, a second space 62, and a third space 63 are formed that are parallel to one another and extend from the heat exchanger group 30 to the cooling fan group 40. Specifically, the first space 61 is formed by the second side surface portion 56, a part of the bottom surface portion 57, and a part of the top surface portion 58 of the peripheral wall 51, and the second partition wall 53. The third space 63 is formed by the first side surface portion 55, a part of the bottom surface portion 57, and a part of the top surface portion 58 of the peripheral wall 51, and the first partition wall 52. A second space 62 adjacent to the first space 61 and the third space 63 is formed by the remainder of the lower surface portion 57 of the peripheral wall 51, the remainder of the upper surface portion 58, the first partition wall 52, and the second partition wall 53. In other words, the first partition wall 52 separates the adjacent second space 62 and third space 63, and the second partition wall 53 separates the adjacent first space 61 and second space 62.

[0029] One end 52a (end on the heat exchanger group 30 side) of the first partition wall 52 is located on the boundary between the adjacent radiator 32 and oil cooler 33. One end 53a (end on the heat exchanger group 30 side) of the second partition wall 53 is located on the boundary between the adjacent intercooler 31 and radiator 32. That is, the intercooler 31 is disposed at an opening on one side of the first space 61, the radiator 32 is disposed at an opening on one side of the second space 62, and the oil cooler 33 is disposed at an opening on one side of the third space 63. As shown in FIG. 6 , the first partition wall 52 is inclined so that the other end 52b (end on the cooling fan group 40 side) is closer to the first side surface portion 55 of the peripheral wall 51 than the one end 52a (end on the heat exchanger group 30 side). The second partition wall 53 is formed to be approximately parallel to the second side surface portion 56 of the peripheral wall 51. The second partition wall 53 has a notch 53c at its other end 53b (the end on the cooling fan group 40 side) at a position corresponding to the first fan 41. The notch 53c of the second partition wall 53 is formed up to the surfaces of the first heat exchanger 31 and the second heat exchanger 32. In other words, the first space 61 and the second space 62 separated by the second partition wall 53 communicate with each other via the notch 53c. The notch 53c of the second partition wall 53 makes it possible to hold the impeller of the sixth fan 46 inside the casing 50.

[0030] 4 and 6, a mounting wall portion 59 for mounting the cooling fan group 40 is provided on the other side in the extension direction of the peripheral wall 51 (upper side in FIG. 6). The mounting wall portion 59 closes the opening on the other side of the peripheral wall 51 (first space 61, second space 62, third space 63). Six mounting holes 59a, 59b, 59c, 59d, 59e, and 59f are formed in the mounting wall portion 59, corresponding to the number of fans in the cooling fan group 40. The impellers of the first fan 41, the second fan 42, the third fan 43, the fourth fan 44, the fifth fan 45, and the sixth fan 46 are arranged inside the first mounting hole 59a, the second mounting hole 59b, the third mounting hole 59c, the fourth mounting hole 59d, the fifth mounting hole 59e, and the sixth mounting hole 59f, respectively, and the rings 49 of the first fan 41 to the sixth fan 46 are respectively provided at the opening edges of the first mounting hole 59a to the sixth mounting hole 59f so as to protrude outward.

[0031] The first mounting hole 59a is formed at a position spanning the other end 53b of the second partition wall 53. That is, the first fan 41 is disposed so as to face the other end 53b of the second partition wall 53 and span only the adjacent first space 61 and second space 62. The first fan 41 can hold the impeller inside the casing 50 by means of the notch 53c of the second partition wall 53. The second mounting hole 59b, the third mounting hole 59c, and the fourth mounting hole 59d are positioned between the other end 52b of the first partition wall 52 and the other end 53b of the second partition wall 53 (the end on the cooling fan group 40 side). That is, the second fan 42, the third fan 43, and the fourth fan 44 are arranged at positions corresponding to the range of the second space 62 (positions between the first partition wall 52 and the second partition wall 53) without straddling the other end 52b of the first partition wall 52 and the other end 53b of the second partition wall 53. The fifth mounting hole 59e and the sixth mounting hole 59f are located between the first side surface portion 55 of the peripheral wall 51 and the other end 52b of the first partition wall 52 (the end on the cooling fan group 40 side). That is, the fifth fan 45 and the sixth fan 46 are arranged at positions corresponding to the range of the third space 63 (positions between the first side surface portion 55 of the peripheral wall 51 and the first partition wall 52) without straddling the other end 52b of the first partition wall 52.

[0032] In cooling unit 26 of the present embodiment, the arrangement of multiple fans 41-46 is determined by various constraints, such as the size and shape of each heat exchanger 41, 42, 43, the size of each fan 41-46, the size of casing 50, and the arrangement of various devices around cooling unit 26. In cooling unit 26, the number of fans is not assigned individually to each heat exchanger 31, 32, 33, but the air volume supplied to each heat exchanger 31, 32, 33 is adjusted by adjusting the positions of end portions 52b, 53b of partition walls 52, 53 on the cooling fan group 40 side to distribute the air volume of one fan.

[0033] In the cooling unit 26 configured as described above, the cooling air generated by each of the fans 41 to 46 constituting the cooling fan group 40 flows as follows: The cooling air generated by the first fan 41 is supplied to both the first heat exchanger 31 and the second heat exchanger 32, passes through both the first space 61 and the second space 62 in the casing 50, and flows out from the first mounting hole 59a in the casing 50. The cooling air generated by the second fan 42 is supplied to the second heat exchanger 32, passes through the second space 62 in the casing 50, and flows out from the second mounting hole 59b in the casing 50. The cooling air generated by the third fan 43 is supplied to the second heat exchanger 32, passes through the second space 62 in the casing 50, and flows out from the third mounting hole 59c in the casing 50. The cooling air generated by the fourth fan 44 is supplied to the second heat exchanger 32, passes through the second space 62 in the casing 50, and flows out from the fourth mounting hole 59d in the casing 50. Note that some of the cooling air generated by the second to fourth fans 42 to 44 may flow from the first space 61 to the second space 62 through the notch 53c in the second partition wall 53. The cooling air generated by the fifth fan 45 is supplied only to the third heat exchanger 33, passes only through the third space 63 in the casing 50, and flows out from the fifth mounting hole 59e in the casing 50. The cooling air generated by the sixth fan 46 is supplied only to the third heat exchanger 33, passes only through the third space 63 in the casing 50, and flows out from the sixth mounting hole 59f in the casing 50. In this way, the cooling air from the second to fourth fans 42 to 44 is supplied to the second heat exchanger 32 and passes through the second space 62 in the casing 50, and they influence each other. Furthermore, the cooling air from the first fan 41 is supplied to both the first heat exchanger 31 and the second heat exchanger 32 and passes through both the first space 61 and the second space 62 in the casing 50, and affects the flow of the cooling air from the second to fourth fans 43 to 45. Furthermore, the cooling air from the fifth and sixth fans 45 to 46 is supplied only to the third heat exchanger 33 and passes only through the third space 63 in the casing 50, and they influence each other. In contrast, the cooling air from the first to fourth fans 41 to 44 and the cooling air from the fifth and sixth fans 45 to 46 do not influence each other.

[0034] Therefore, in this embodiment, the fans 41-46 constituting the cooling fan group 40 and the heat exchangers 41-43 constituting the heat exchanger group 30 are grouped into a plurality of groups, each group including fans whose cooling airflows generated as described above influence each other due to the relative positions of the fans 41-46 and the heat exchangers 41-43, and the heat exchangers to which the cooling airflows generated by the fans are supplied. That is, in the cooling unit 26 of this embodiment, a first group is formed by associating the first to fourth fans 41-44 with the first and second heat exchangers 31-32, and a second group is formed by associating the fifth and sixth fans 45-46 with the third heat exchanger 33. The first group shares both the first space 61 and the second space 62 as flow paths, and the flow path shared by the first group is referred to as a first shared flow path. The cooling airflow generated by the first to fourth fans 41-44 is entirely supplied to the first and second heat exchangers 31-32 and passes through the first shared flow path (the first space 61 and the second space 62). The second group shares the third space 63 as a flow path, and the flow path shared by the second group is referred to as the second shared flow path. The cooling airflow generated by the fifth and sixth fans 45-46 is entirely supplied to the third heat exchanger 33 and passes through the second shared flow path (the third space 63). In other words, the first shared flow path (the first space 61 and the second space 62) and the second shared flow path (the third space 63) are completely separated from each other. The first partition wall 52 functions as a separation wall that separates the space surrounded by the peripheral wall 51 into the first shared flow path (the first space 61 and the second space 62) and the second shared flow path (the third space 63). Although the second partition wall 53 separates the first space 61 and the second space 62, it does not function as a separation wall that separates the shared flow paths due to the presence of the notch 53c.

[0035] This embodiment is characterized in that the multiple fans 41 to 46 of the cooling unit 26 are controlled in units of associated groups. That is, the first fan 41, the second fan 42, the third fan 43, and the fourth fan 44 associated with the first group are all driven in the same way, and the fifth fan 45 and the sixth fan 46 associated with the second group are also driven in the same way. The driving of the multiple fans 41 to 46 is controlled by a controller 80 (see FIG. 7 ) described below. Details of the driving control of the multiple fans 41 to 46 by the controller 80 will be described later.

[0036] Next, the hardware configuration and functional configuration of the controller that constitutes a part of the first embodiment of the construction machine of the present invention will be described with reference to Fig. 7. Fig. 7 is a block diagram showing the functional configuration of the controller that constitutes a part of the first embodiment of the construction machine of the present invention.

[0037] 7, a key switch 18 is electrically connected to the controller 80. The key switch 18 instructs the start and stop of the hydraulic excavator 1, and outputs to the controller 80 an ON signal (start instruction signal) instructing the start of the hydraulic excavator 1 or an OFF signal (operation stop instruction signal) instructing the operation of the hydraulic excavator 1 to stop.

[0038] The controller 80 is electrically connected to a first temperature sensor 35 that detects the temperature of the first heat exchanger 31, a second temperature sensor 36 that detects the temperature of the second heat exchanger 32, and a third temperature sensor 37 that detects the temperature of the third heat exchanger 33. Each of the temperature sensors 35, 36, and 37 outputs a detection signal corresponding to the detected temperature of each of the heat exchangers 31, 32, and 33 to the controller 80.

[0039] The controller 80 controls the driving of the first to sixth fans 41 to 46 of the cooling unit 26 in accordance with the cooling states of the first to third heat exchangers 31 to 33 (see FIG. 3) of the cooling unit 26. The controller 80 has a built-in microcomputer, which includes, as its hardware configuration, a storage device 81 including a ROM, a RAM, etc., and a processing device 82 including a CPU, an MPU, etc. The storage device 81 stores in advance programs and various information required for controlling the driving of the first to sixth fans 41 to 46. The processing device 82 reads various programs and information from the storage device 81 as appropriate, and performs processing in accordance with the programs, thereby realizing various functions.

[0040] A feature of the control by the controller 80 of this embodiment is that the first to sixth fans 41-46 and the first to third heat exchangers 31-33 are associated with each other and classified into multiple groups, and all of the fans constituting each group are controlled using the same target rotation speed. That is, the controller 80 controls all of the first to fourth fans 41-44 associated with the first group using the same target rotation speed, and controls both the fifth fan 45 and the sixth fan 46 associated with the second group using the same target rotation speed. The target rotation speed for the fans in each group is set according to the load (required heat dissipation amount) of the heat exchangers constituting each group. Therefore, the target rotation speed for the first group and the target rotation speed for the second group may be different or the same depending on the cooling state of the first and second heat exchangers 31-32 constituting the first group and the cooling state of the third heat exchanger 33 constituting the second group. That is, for the first group, the controller 80 outputs a control command to the first to fourth fans 41 to 44 to rotate them at the same rotation speed in accordance with the temperature of the coolant (fluid) passing through the radiator 32 or the temperature of the intake air (fluid) passing through the intercooler 31. For the second group, the controller 80 outputs a control command to the fifth fan 45 and the sixth fan 46 to rotate them at the same rotation speed in accordance with the temperature of the hydraulic oil (fluid) passing through the oil cooler 33. In this way, the fans in each group that affect each other are controlled to rotate at approximately the same rotation speed.

[0041] The controller 80 includes, for example, a cooling state determination unit 84 and a fan control unit 85 as functions for controlling the drive of the first to sixth fans 41 to 46, which are executed by the processing device 72.

[0042] First, the cooling state determination unit 84 determines the cooling state (presence or absence of overheating) for each group of the plurality of heat exchangers 31 to 33. That is, it determines the cooling state (presence or absence of overheating) of the first heat exchanger (intercooler) 31 or the second heat exchanger (radiator) 32 constituting the first group, and also determines the cooling state (presence or absence of overheating) of the third heat exchanger (oil cooler) 33 constituting the second group.

[0043] Specifically, the cooling state determination unit 84 determines the cooling states of the heat exchangers 31, 32 of the first group. Specifically, first, it determines whether the temperature of the second heat exchanger 32, which is the detection value T2 of the second temperature sensor 36, is higher than the temperature of the first heat exchanger 31, which is the detection value T1 of the first temperature sensor 35. If the detection value T2 of the second temperature sensor 36 is higher, it determines whether the detection value T2 of the second temperature sensor 36 is lower than a second threshold value S2. The second threshold value S2 is a value used to determine whether the second heat exchanger 32 has overheated, and is stored in advance in the storage device 81. On the other hand, if the detection value T1 of the first temperature sensor 35 is higher than the detection value T2 of the second temperature sensor 36, it determines whether the detection value T1 of the first temperature sensor 35 is lower than a first threshold value S1. The first threshold value S1 is a value used to determine whether the first heat exchanger 31 has overheated, and is stored in advance in the storage device 81.

[0044] Furthermore, in order to determine the cooling state of the third heat exchanger 33 of the second group, the cooling state determination unit 84 determines whether the temperature of the third heat exchanger 33, which is the detected value T3 of the third temperature sensor 37, is lower than a third threshold value S3. The third threshold value S3 is a value used to determine whether the third heat exchanger 33 (second group) has overheated, and is stored in advance in the storage device 81.

[0045] Secondly, the cooling state determination unit 84 determines the start timing of the first to sixth fans 41 to 46. For example, the start timing of the first to sixth fans 41 to 46 is set to the completion time of warm-up when the engine 23 (see FIG. 2) is started or is cold. Specifically, the cooling state determination unit 84 determines whether warm-up of the engine 23 is complete or not by determining whether the temperature of the radiator (second heat exchanger) 32, which is the detection value T2 of the second temperature sensor 36, is higher than the start threshold value Ss. The start threshold value Ss is stored in advance in the storage device 81.

[0046] The fan control unit 85 controls the rotation speeds of the multiple fans 41 to 46 in accordance with the determination by the cooling state determination unit 84. A feature of the fan control unit 85 of this embodiment is that it controls the rotation speeds of the multiple fans 41 to 46 using the same target rotation speed for each group of fans. That is, the fan control unit 85 sets the same target rotation speed for the fans 41 to 44 of the first group in accordance with the determination by the cooling state determination unit 84 of the cooling state of the heat exchangers 31 and 32 of the first group, and sets the same target rotation speed for the fans 45 and 46 of the second group in accordance with the determination by the cooling state determination unit 84 of the cooling state of the heat exchanger 33 of the second group.

[0047] Specifically, if the cooling state determination unit 84 determines that the heat exchangers 31, 32 of the first group are not in an overheated state, the fan control unit 85 maintains the current target rotation speed and outputs a control command to all of the first to fourth fans 41-44 of the first group to rotate at the same maintained target rotation speed. As a result, all of the first to fourth fans 41-44 of the first group are controlled to approach the same currently maintained target rotation speed. On the other hand, if the cooling state determination unit 84 determines that the heat exchangers 31, 32 of the first group are in an overheated state, the fan control unit 85 changes the current target rotation speed to an increased value and outputs a control command to all of the first to fourth fans 41-44 of the first group to rotate at the same changed target rotation speed. As a result, all of the first to fourth fans 41-44 of the first group are controlled to approach the same changed target rotation speed.

[0048] Furthermore, if the cooling state determination unit 84 determines that the heat exchanger 33 of the second group is not in an overheated state, the fan control unit 85 maintains the current target rotation speed and outputs a control command to all of the fifth and sixth fans 45-46 of the second group to rotate at the same maintained target rotation speed. As a result, all of the fifth to sixth fans 45-46 of the second group are controlled to approach the same currently maintained target rotation speed. On the other hand, if the cooling state determination unit 84 determines that the heat exchanger 33 of the second group is in an overheated state, the fan control unit 85 changes the current target rotation speed to an increased value and outputs a control command to all of the fifth to sixth fans 45-46 of the second group to rotate at the same changed target rotation speed. As a result, all of the fifth to sixth fans 45-46 of the second group are controlled to approach the same changed target rotation speed.

[0049] Furthermore, the fan control unit 85 controls the activation of the first to sixth fans 41 to 46 in response to the determination by the cooling state determination unit 84 that the warm-up of the engine 23 has been completed. A feature of the fan control unit 85 of this embodiment is that it activates the fans in each group so that their rotation speeds increase in unison. Specifically, when the cooling state determination unit 84 determines that the warm-up of the engine 23 has been completed, the fan control unit 85 controls the rotation speeds of the first to fourth fans 41 to 44 of the first group so that they all increase at the same rate of increase, and also controls the rotation speeds of the fifth and sixth fans 45 to 46 of the second group so that they all increase at the same rate of increase.

[0050] Next, the processing procedure for controlling the drive of the cooling unit fan by the controller in the first embodiment of the construction machine of the present invention will be described with reference to Fig. 8. Fig. 8 is a flowchart showing an example of the processing procedure for controlling the drive of the cooling unit fan by the controller shown in Fig. 7.

[0051] 7 is input to the controller 80, the controller 80 first performs start control of the engine 23 (step S10), and then performs warm-up control of the engine 23 (step S20). Next, the controller 80 determines whether or not the warm-up of the engine 23 is complete (step S30). Specifically, the controller 80 determines whether or not the temperature of the second heat exchanger (radiator) 32, which is the detection value T2 of the second temperature sensor 36, is higher than the start threshold value Ss.

[0052] In step S30, if the detection value T2 of the second temperature sensor 36 is equal to or lower than the start-up threshold value Ss (NO), the controller 80 returns to step S20 and continues warm-up control of the engine 23 until the detection value T2 of the second temperature sensor 36 becomes higher than the start-up threshold value Ss in step S30.

[0053] On the other hand, if the detection value T2 of the second temperature sensor 36 is higher than the activation threshold Ss in step S30 (YES), the controller 80 performs activation control of the first group of fans 41-44 and the second group of fans 45-46 (step S40). Specifically, the controller 80 synchronizes and increases the rotation speeds of all of the first group of fans 41-44 so that the rotation speeds of all of the first group of fans 41-44 approach the same target rotation speed. Similarly, the controller 80 synchronizes and increases the rotation speeds of all of the second group of fans 45-46 so that the rotation speeds of all of the second group of fans 45-46 approach the same target rotation speed.

[0054] After completing the startup control of the first group of fans 41 to 44 and the second group of fans 45 to 46 (step S40), the controller 80 controls the rotation speed of the second group of fans 45 to 46 in accordance with the cooling state of the second group of heat exchanger 33 (steps S110 to S130), and also controls the rotation speed of the first group of fans 41 to 44 in accordance with the cooling state of the first group of heat exchangers 31, 32 (steps S210 to S270).

[0055] In controlling the rotation speed of the fans 45-46 of the second group, the controller 80 first determines whether the heat exchanger 33 of the second group is overheating (step S110). Specifically, it determines whether the detected value T3 of the third temperature sensor 37 is lower than the third threshold value S3. If the detected value T3 of the third temperature sensor 37 is lower than the third threshold value S3 (YES), the process proceeds to step 120, and if it is equal to or higher than the third threshold value S3 (NO), the process proceeds to step 130.

[0056] If the determination in step S110 is YES, that is, if it is determined that the heat exchanger 33 of the second group is not in an overheated state, the controller 80 maintains the target rotation speeds of the fans 45-46 of the second group and controls all of the fans 45-46 of the second group to approach the same target rotation speed (step 120), and then returns to step S110. Step 120 is repeated until the determination in step S110 is NO. That is, the controller 80 maintains the current control of the fans 45-46 of the second group as long as the heat exchanger 33 of the second group remains in a non-overheated state.

[0057] On the other hand, if the determination in step S110 is NO, that is, if it is determined that the heat exchanger 33 of the second group is in an overheated state, the controller 80 increases the target rotation speed from the current state and outputs it to all of the fans 45-46 of the second group (step S130), and then returns to step S110. As a result, the fans 45-46 of the second group are controlled to approach the changed target rotation speed. Step S130 is repeated until the determination in step S110 is YES. That is, the target rotation speed of the fans 45-46 of the second group is increased until the heat exchanger 33 of the second group is released from the overheated state, and all of the fans 45-46 of the second group are controlled to approach the same increased target rotation speed.

[0058] In controlling the rotation speeds of the fans 41-44 of the first group, the controller 80 first determines whether the heat exchangers of the first group have overheated. Specifically, it determines whether the detected value T2 of the second temperature sensor 36 is higher than the detected value T1 of the first temperature sensor 35 (step S210). If the detected value T2 of the second temperature sensor 36 is higher in step S210, it determines whether the detected value T2 of the second temperature sensor 36 is lower than a second threshold value S2 (step S220). On the other hand, if the detected value T1 of the first temperature sensor 35 is higher, it determines whether the detected value T1 of the first temperature sensor 35 is lower than a first threshold value S1 (step S250). In other words, it determines whether the heat exchangers of the first group have overheated by determining whether the higher-temperature heat exchanger, either the first heat exchanger 31 or the second heat exchanger 32, that constitutes the first group has overheated.

[0059] In step S220, if the detected value T2 of the second temperature sensor 36 is lower than the second threshold value S2 (if YES), the process proceeds to step 230. On the other hand, if the detected value T2 of the second temperature sensor 36 is equal to or greater than the second threshold value S2 (if NO), the process proceeds to step 240.

[0060] If the determination in step S220 is YES, i.e., if it is determined that the second heat exchanger 32 of the first group is not in an overheated state, the controller 80 maintains the target rotation speeds of the fans 41-44 of the first group and controls all of the fans 41-44 of the first group to approach the same target rotation speed (step S230), and then returns to step S210. Step S230 is repeated until a NO determination is made in step S210 or step S220. That is, the controller 80 maintains the current control of the fans 41-44 of the first group as long as the heat exchangers 31, 32 of the first group remain in a non-overheated state.

[0061] On the other hand, if the determination in step S220 is NO, i.e., if it is determined that the second heat exchanger 32 of the first group is in an overheated state, the controller 80 increases the target rotation speed setting from the current setting and outputs the increased target rotation speed to all of the fans 41-44 of the first group (step S240), and then returns to step S210. As a result, all of the fans 41-44 of the first group are controlled to approach the same changed target rotation speed. Step S240 is repeated until the determination in step S210 is NO or the determination in step S220 is YES. That is, until the second heat exchanger 32 of the first group is released from the overheated state, the target rotation speeds of the fans 41-44 of the first group are increased, and all of the fans 41-44 of the first group are controlled to approach the same increased target rotation speed.

[0062] If the detected value T1 of the first temperature sensor 35 is lower than the first threshold value S1 (YES in step S250), the process proceeds to step 260. On the other hand, if the detected value T1 of the first temperature sensor 35 is equal to or greater than the first threshold value S1 (NO in step S250), the process proceeds to step 270.

[0063] If the determination in step S250 is YES, i.e., if it is determined that the first heat exchanger 31 of the first group is not in an overheated state, the controller 80 maintains the target rotation speeds of the fans 41-44 of the first group and controls all of the fans 41-44 of the first group to approach the same target rotation speed (step S260), and then returns to step S210. Step S260 is repeated until the determination in step S210 is YES or the determination in step S250 is NO. That is, the controller 80 maintains the current control of the fans 41-44 of the first group as long as the heat exchanger 31 of the first group remains in a non-overheated state.

[0064] On the other hand, if the determination in step S250 is NO, i.e., if it is determined that the first heat exchanger 31 of the first group is in an overheated state, the controller 80 increases the target rotation speed from the current value and outputs it to all of the fans 41-44 of the first group (step S270), and then returns to step S210. As a result, the fans 41-44 of the first group are controlled to approach the same changed target rotation speed. Step S270 is repeated until the determination in step S210 or step S250 is YES. That is, the target rotation speeds of the fans 41-44 of the first group are increased until the heat exchanger 31 of the first group is released from the overheated state, and all of the fans 41-44 of the first group are controlled to approach the same increased target rotation speed.

[0065] Next, the effects of the first embodiment of the construction machine of the present invention will be described.

[0066] In this embodiment, the multiple fans 41-46 constituting the cooling fan group 40 and the multiple heat exchangers 41-43 constituting the heat exchanger group 30 are classified into multiple groups, with the fans that affect each other and the heat exchangers to which the cooling air generated by the fans is supplied corresponding to each other. That is, the first group is formed by associating the first to fourth fans 41-44 with the first and second heat exchangers 31, 32, and the second group is formed by associating the fifth and sixth fans 45, 46 with the third heat exchanger 33. In the first group, all of the cooling air generated by the first to fourth fans 41-44 is supplied to the first and second heat exchangers 31, 32 and passes through the first shared flow path (the first space 61 and the second space 62). In the second group, all of the cooling airflow generated by the fifth and sixth fans 45, 46 is supplied to the third heat exchanger 33 and passes through the second shared flow path (third space 63). The cooling airflows generated by the fans 41, 42, 43, 44 of the first group affect each other, and the cooling airflows generated by the fans 45, 46 of the second group affect each other. On the other hand, the cooling airflow generated by the first group and flowing through the first shared flow path and the cooling airflow generated by the second group and flowing through the second shared flow path do not interfere with or affect each other.

[0067] Therefore, in this embodiment, the fans constituting each group are controlled to rotate at approximately the same rotation speed. That is, the controller 80 outputs a control command to the fans 41-44 of the first group to rotate them at the same rotation speed, and also outputs a control command to the fans 45, 46 of the second group to rotate them at the same rotation speed. This causes the flow speed of the cooling airflow generated by the fans 41-44 of the first group in the first shared flow path to be approximately the same. Similarly, the flow speed of the cooling airflow generated by the fans 45, 46 of the second group in the second shared flow path to be approximately the same.

[0068] In contrast, consider a case where the rotation speeds of the second to fourth fans 42 to 44 of the first group of fans 41 to 44 are controlled to be higher than the rotation speed of the first fan 41. Because the radiator 32 of the first group generally exchanges more heat than the intercooler 31, it is assumed that an attempt is made to supply a larger amount of cooling air to the radiator 32 than to the intercooler 31. In this case, the flow velocity of the cooling air generated by the first fan 41 is slower than the flow velocity of the cooling air generated by the second to fourth fans 42 to 44. As a result, the flow velocity distribution in the first shared flow path (the first space 61 and the second space 62) through which the cooling air from the first fan 41 and the cooling air from the second to fourth fans 42 to 44 flows becomes non-uniform. It has been confirmed that this causes loss due to mixing of the relatively slow-flowing cooling air from the first fan 41 and the relatively fast-flowing cooling air from the second to fourth fans 42 to 44. In order to compensate for the loss caused by the mixing of cooling airflows with different flow speeds in the first shared flow path (first space 61 and second space 62), the total power consumption of the first group of fans 41 to 44 increases.

[0069] Furthermore, if there is a significant difference in the rotation speeds of fans in the same group, differences in the suction pressures of the fans will occur, potentially resulting in backflow from one fan to another. This can lead to problems such as insufficient cooling in the heat exchanger. Furthermore, because fan noise is generally proportional to the fifth or sixth power of the rotation speed, increasing the rotation speed of some of the fans in each group will increase the noise accordingly.

[0070] In contrast, in this embodiment, the flow speed of the cooling air generated by each of the fans 41-44 of the first group is approximately the same. Similarly, the flow speed of the cooling air generated by each of the fans 45 and 46 of the second group is approximately the same. Therefore, the flow speed distribution in the first shared flow path (first space 61 and second space 62) through which the cooling air from the first to fourth fans 41-44 of the first group flows is approximately uniform, so loss due to mixing of the cooling air from the first to fourth fans 41-44 of the first group is extremely small. Similarly, the flow speed distribution in the second shared flow path (third space 63) through which the cooling air from the fifth and sixth fans 45-46 of the second group flows is approximately uniform, so loss due to mixing of the cooling air from the fifth and sixth fans 45-46 of the second group is extremely small. Furthermore, since the rotation speed of the fans in each group is controlled to be approximately the same, the load on the fans in each group can be made equal, which reduces the overall driving power of the multiple fans 41 to 46 and also suppresses noise.

[0071] As described above, the hydraulic excavator 1 (construction machine) according to the first embodiment of the present invention includes a casing 50 having a peripheral wall 51, a plurality of heat exchangers 31-33 arranged in parallel across the peripheral wall 51, a plurality of fans 41-46 that supply cooling air to the plurality of heat exchangers 31-33, and a controller 80 that controls the rotation speeds of the plurality of fans 41-46. The plurality of heat exchangers 31-33 are classified into a first group and a second group (a plurality of groups), and each of the plurality of heat exchangers 31-33 belongs to only one of the first group or the second group (a plurality of groups). Each of the plurality of fans 41-46 is arranged so as to correspond to only one of the first group or the second group (a plurality of groups), and at least one fan is associated with each group of the heat exchangers 31-33. A first partition wall 52 (separation wall) is disposed within the space surrounded by the peripheral wall 51 so as to separate the flow paths from each group of heat exchangers 31-33 to the associated fans 41-46. The multiple groups include a first group (specific group) configured to include adjacent heat exchangers. Two or more fans 41-44 are associated with the first group (specific group) 31, 32 of heat exchangers, and a first fan 41, which is one of the two or more fans 41-44 associated with the first group (specific group) 31, 32 of heat exchangers, is disposed on the boundary between the first heat exchanger 31 and the second heat exchanger 32 that belong to the first group (specific group) and are arranged adjacent to each other. The controller 80 is configured to output a control command to rotate the first fan 41 and the other fans 42-44 associated with the first group (specific group) 31, 32 of heat exchangers at the same rotation speed.

[0072] According to this configuration, when the first fan 41 is positioned to supply cooling air to adjacent heat exchangers 31-32 due to restrictions on the relative arrangement of the heat exchangers 31-33 and the fans 41-46, the rotation speeds of two or more fans 41-44, including the first fan 41 associated with a first group (specific group) including the adjacent heat exchangers 31-32, are controlled by the same rotation speed control command. This results in a substantially uniform flow velocity distribution in the first shared flow paths (flow paths) 61, 62 through which the cooling air generated by the two or more fans 41-44, including the first fan 41 of the first group (specific group), flows, thereby minimizing loss due to mixing of the cooling air in the first group (specific group). Therefore, even if there are restrictions on the relative arrangement of the heat exchangers 31-33 and the fans 41-46 and the required air volume (heat exchange volume) and suction force differ significantly between the heat exchangers 31-33, an increase in the overall driving power of the fans 41-46 can be prevented.

[0073] Furthermore, in this embodiment, the controller 80 is configured to control two or more fans 41-44, including the first fan 41 associated with the first group (specific group) 31-32 of the heat exchangers, so that the rotation speeds of the fans 41-44 increase in unison when the fans 41-44 are started. This configuration makes it possible to prevent backflow when the two or more fans 41-44 associated with the first group (specific group) 31-32 are started.

[0074] In this embodiment, a part of the flow path through which the cooling air generated by two or more fans 41-44, including the first fan 41 associated with the first group (specific group) 31-32 of heat exchangers, flows is partitioned by a second partition wall 53 (partition wall) extending from the heat exchanger side toward the fan side. The second partition wall 53 (partition wall) has a heat exchanger-side end 53a located on the boundary between the first heat exchanger 31 and the second heat exchanger 32 of the first group (specific group), and a fan-side end 53b located opposite the first fan 41. Furthermore, the second partition wall 53 (partition wall) has a notch 53c in a portion of the fan-side end 53b facing the first fan 41, and the first fan 41 is disposed in the notch 53c.

[0075] With this configuration, the second partition wall 53 makes it possible to easily distribute the cooling air generated by the first fan 41 to adjacent heat exchangers 31-32 in the first group (specific group), and the notch 3c in the second partition wall 53 makes it possible to position the first fan 41 within the first shared flow path (flow path) 61, 62 of the peripheral wall 51.

[0076] [Second embodiment] Next, a second embodiment of the construction machine of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a block diagram showing the functional configuration of a controller that constitutes part of the second embodiment of the construction machine of the present invention. In Figure 9, the same reference numerals as those shown in Figures 1 to 8 indicate similar parts, and therefore detailed description thereof will be omitted.

[0077] The second embodiment of the construction machine of the present invention differs from the first embodiment in that the controller 80A controls the drive of the fans 41-46 of the cooling unit 26. In addition to controlling the heat exchangers 31-33 of each group to prevent them from overheating, the controller 80A also controls the heat exchangers 31-33 of each group to prevent them from overcooling. Furthermore, of the intercooler 31 and radiator 32 that make up the first group of heat exchangers, the radiator 32 generally requires a greater amount of heat radiation than the intercooler 31. Therefore, the rotation speeds of the first to fourth fans 41-44 of the first group are controlled using only the temperature of the cooling water in the radiator 32, without using the temperature of the intercooler 31.

[0078] Specifically, the cooling state determination unit 84A determines whether the heat exchangers in the first group are overheated and whether they are subcooled. The determination of whether the heat exchangers in the first group are overheated is performed using only the temperature of the radiator 32. Specifically, the comparison between the detected value T2 of the second temperature sensor 36 and the detected value T1 of the first temperature sensor 35 is omitted, and, as in the first embodiment, the determination is made by determining whether the detected value T2 of the second temperature sensor 36 is lower than the second threshold value S2. That is, only the determination of whether the radiator 32 is overheated is performed, and the determination of whether the intercooler 31 is overheated is not performed. The determination of whether the heat exchangers in the first group are subcooled is performed using only the temperature of the radiator 32. Specifically, the determination is made by determining whether the temperature of the second heat exchanger 32, which is the detected value T2 of the second temperature sensor 36, is lower than a fifth threshold value S5. The fifth threshold value S5 is pre-stored in the storage device 81.

[0079] 9 determines whether the third heat exchanger 33 of the second group is overheated and whether it is supercooled. The determination of whether the heat exchanger 33 of the second group is overheated is the same as in the first embodiment. The determination of whether the heat exchanger 33 of the second group is supercooled is performed by determining whether the temperature of the third heat exchanger 33, which is the detection value T3 of the third temperature sensor 37, is lower than a fourth threshold value S4. The fourth threshold value S4 is stored in advance in the storage device 81.

[0080] The fan control unit 85A controls the rotation speeds of the multiple fans 41-46 in accordance with the determination by the cooling state determination unit 84A. Specifically, when the cooling state determination unit 84A determines that the heat exchanger 32 of the first group is neither overheated nor supercooled, the fan control unit 85A maintains the current target rotation speeds and controls all of the first to fourth fans 41-44 of the first group to approach the same maintained target rotation speeds. On the other hand, when the heat exchanger 32 of the first group is determined to be overheated, the fan control unit 85A controls the first to fourth fans 41-44 of the first group in the same manner as in the first embodiment. Furthermore, when the cooling state determination unit 84A determines that the heat exchanger 32 of the first group is supercooled, the fan control unit 85A decreases the current target rotation speeds and controls all of the first to fourth fans 41-44 of the first group to approach the same changed target rotation speeds.

[0081] Furthermore, when the cooling state determination unit 84A determines that the heat exchanger 33 of the second group is neither overheated nor supercooled, the fan control unit 85A maintains the current target rotation speed and outputs a control command to all of the fifth and sixth fans 45, 46 of the second group to rotate at the same maintained target rotation speed. On the other hand, when the heat exchanger 33 of the second group is determined to be overheated, the fan control unit 85A controls the fifth and sixth fans 45, 46 of the second group in the same manner as in the first embodiment. When the cooling state determination unit 84A determines that the heat exchanger 33 of the second group is supercooled, the fan control unit 85A decreases the current target rotation speed and outputs a control command to all of the fifth and sixth fans 45, 46 of the second group to rotate at the same changed target rotation speed.

[0082] Next, an example of a procedure for controlling the fan of the cooling unit by the controller in the second embodiment of the construction machine of the present invention will be described with reference to Fig. 10. Fig. 10 is a flowchart showing an example of a processing procedure for controlling the drive of the fan of the cooling unit by the controller shown in Fig. 9. In Fig. 10, the same reference numerals as those in Figs. 1 to 8 indicate similar parts, and therefore detailed description thereof will be omitted.

[0083] The startup control of the fans 41-46 of the cooling unit 26 by the controller 80A (steps S10-S40 in the flowchart shown in FIG. 10) is the same as in the first embodiment. After step S40 is completed, the rotation speeds of the fans 45-46 of the second group are controlled (steps S110, S115, S120, S125, S130), and the rotation speeds of the fans 41-44 of the first group are controlled (steps S220, S225, S230, S235, S240).

[0084] In controlling the rotation speeds of the second group of fans 45-46, steps S115 and S125 are different from those in the first embodiment. If the controller 80A determines that the heat exchanger 33 of the second group is not in an overheated state (step S110), the controller 80A determines whether the heat exchanger 33 of the second group is in a supercooled state (step S115). Specifically, the controller 80A determines whether the temperature of the first heat exchanger 33, which is the detected value T3 of the third temperature sensor 37, is lower than a fourth threshold value S4. If the answer is NO in step S115, that is, if the controller 80A determines that the heat exchanger 33 of the second group is neither in an overheated state nor a supercooled state, the controller 80A maintains the target rotation speeds of the second group of fans 45-46 and controls all of the second group of fans 45-46 to approach the same target rotation speeds (step S120), as in the first embodiment. On the other hand, if the answer is YES in step S115, that is, if it is determined that the heat exchanger 31 of the second group is in a supercooled state, the current target rotation speed is changed to a lower value, and a control command is output to all of the fifth and sixth fans 45, 46 of the second group to rotate at the same changed target rotation speed (step S125).

[0085] In controlling the rotation speeds of the first group of fans 41-44, steps S225 and S235 are different from those in the first embodiment. If the controller 80A determines that the heat exchanger 32 of the first group is not in an overheated state (step S220), the controller 80A determines whether the heat exchanger 32 of the first group is in a supercooled state (step S225). Specifically, the controller 80A determines whether the detected value T2 of the second temperature sensor 36 is lower than a fifth threshold value S5. If the answer is NO in step S225, that is, if the controller 80A determines that the heat exchanger 32 of the first group is neither overheated nor supercooled, the controller 80A maintains the target rotation speeds of the first to fourth fans 41-44 of the first group, as in the first embodiment, and controls all of the first to fourth fans 41-44 of the first group to approach the same maintained target rotation speed (step S230). On the other hand, if the answer is YES in step S225, that is, if it is determined that the heat exchanger 32 of the first group is in a supercooled state, the current target rotation speed is changed to a decreasing direction, and a control command is output to all of the first to fourth fans 41 to 44 of the first group to rotate them at the same changed target rotation speed (step S235).

[0086] In the second embodiment of the present invention described above, as in the first embodiment, when a first fan 41 is positioned to supply cooling air to adjacent heat exchangers 31-32 due to restrictions on the relative positioning of the multiple heat exchangers 31-33 and the multiple fans 41-46, the rotation speeds of two or more fans 41-44, including the first fan 41 associated with a first group (specific group) that includes the adjacent heat exchangers 31-32, are controlled by the same rotation speed control command. This makes the flow velocity distribution in the first shared flow paths (flow paths) 61, 62, through which the cooling air generated by the two or more fans 41-44, including the first fan 41 of the first group (specific group), flows approximately uniform, thereby reducing losses due to mixing of the cooling air in the first group (specific group). Therefore, even if there are limitations on the relative positions of the heat exchangers 31-33 and the fans 41-46, and the required air volume (heat exchange volume) and suction force differ significantly between the heat exchangers 31-33, it is possible to prevent an increase in the overall driving power of the fans 41-46.

[0087] In the present embodiment described above, the controller 80A is configured to control the rotation speeds of two or more fans 41-44, including the first fan 41 associated with the first group (specific group) 31-32 of heat exchangers, in accordance with the temperature of the coolant (fluid) flowing through the second heat exchanger 32, which has the largest amount of heat exchanged among the heat exchangers 31-32 of the first group (specific group). This configuration eliminates the need for control using the temperatures of the multiple heat exchangers 31-32, thereby simplifying the control of the fans 41-44.

[0088] [Other embodiments] It should be noted that the present invention is not limited to the present embodiment, and various modifications are included. The above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to an embodiment including all of the described configurations. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0089] For example, in the first and second embodiments described above, an example was shown in which the present invention is applied to a hydraulic excavator 1, but the present invention can be widely applied to various types of construction machinery such as hydraulic cranes and wheel loaders.

[0090] In the above-described embodiment, the heat exchanger group 30 arranged in parallel is configured with three heat exchangers: an intercooler (first heat exchanger) 31, a radiator (second heat exchanger) 32, and an oil cooler (third heat exchanger) 33. However, the heat exchanger group arranged in parallel can also be configured with four or more heat exchangers. For example, a configuration including a condenser for cooling the refrigerant of an air conditioner in addition to the three heat exchangers 31, 32, and 33 is conceivable.

[0091] When a heat exchanger group arranged in parallel is composed of four or more heat exchangers, each of the multiple heat exchangers is classified to belong to only one of the multiple groups. Furthermore, each of the multiple fans is arranged to correspond to only one of the multiple groups. Furthermore, at least one fan is associated with each group of heat exchangers. At least one of the multiple groups in the heat exchanger group 30 is configured to include adjacent heat exchangers, and two or more fans are associated with that group. This assumes a case where, due to limitations on the arrangement of the multiple heat exchangers and the multiple fans, it is not possible to arrange fans facing each of the multiple heat exchangers to supply cooling air. In other words, this assumes a case where, due to limitations on the arrangement, a single fan supplies cooling air to two or more adjacent heat exchangers.

[0092] A heat exchanger group may be composed of only one heat exchanger, two adjacent heat exchangers, or three or more adjacent heat exchangers. For example, if a heat exchanger group is composed of four heat exchangers, it may be classified into one group (first group) consisting of two adjacent heat exchangers and two groups (second and third groups) consisting of only one heat exchanger. It may also be classified into two groups (first and second groups) consisting of two adjacent heat exchangers. In this case, it is assumed that at least one of the two or more fans associated with the first group supplies cooling air to both adjacent heat exchangers, and at least one of the two or more fans associated with the second group supplies cooling air to both adjacent heat exchangers. It may also be classified into one group (first group) consisting of three adjacent heat exchangers and one group (second group) consisting of only one heat exchanger.

[0093] An example of three adjacent heat exchangers forming one group is a case where three heat exchangers, each elongated in the vertical direction, such as the intercooler 31, are arranged side by side. In this case, if multiple fans are arranged vertically for the three horizontally arranged heat exchangers, it is expected that each fan will span the width of the three horizontally arranged heat exchangers due to differences in the relative size and shape of each fan and each heat exchanger. In this case, each fan will supply cooling air to all three horizontally arranged heat exchangers. The three horizontally arranged heat exchangers and the multiple fans supplying cooling air to them are associated with one group (specific group). By controlling all of the multiple fans associated with the three horizontally arranged heat exchangers with the same control command for the rotation speed, it is possible to suppress performance degradation due to the interaction of the cooling air generated by the multiple fans.

[0094] The arrangement of three or more adjacent heat exchangers includes arrangements where the heat exchangers are adjacent to each other or arranged side by side. The adjacent heat exchangers may be arranged in complete contact with each other or with a gap or spacer between them.

[0095] Furthermore, in the above-described embodiment, an example has been shown in which electric motors are used as the drive devices for the fans 41 to 46 of the cooling fan group 40, but it is also possible to use hydraulic motors or the like as the drive devices.

[0096] In the above-described embodiment, an example has been shown in which the multiple fans in the cooling fan group 40 all have the same specifications. However, the multiple fans that make up the cooling fan group can also be configured with different specifications, such as shape and size, depending on various conditions such as installation space and price.

[0097] In the above-described embodiment, an example has been shown in which the casing 50 has the first partition wall 52 and the second partition wall 33 having the notch 53c. However, the casing may have only the first partition wall 52, without the second partition wall 33 having the notch 53c.

[0098] In the above-described embodiment, an example of a configuration has been shown in which the controllers 80, 80A control the driving of the multiple fans 41-46 based on the temperatures of the fluids flowing through the heat exchangers 31-33 detected by the temperature sensors 35-37. However, the controllers 80, 80A can also perform control using the temperatures corresponding to the heat exchangers 31-33. For example, it is also possible to perform control based on the surface temperatures of the heat exchangers 31-33 detected by the temperature sensors 35-37. [Explanation of symbols]

[0099] 1...hydraulic excavator (construction machinery), 31...intercooler (heat exchanger, first heat exchanger), 32...radiator (heat exchanger, second heat exchanger), 33...oil cooler (heat exchanger), 41...first fan (fan, first fan), 42...second fan (fan), 43...third fan (fan), 44...fourth fan (fan), 45...fifth fan (fan), 46...sixth fan (fan), 50...casing, 51...circumferential wall, 52...first partition wall (separation wall), 53...second partition wall (partition wall), 53a...one side end (end on heat exchanger side), 53b...other side end (end on fan side), 53c...notch, 61...first space (shared flow path), 62...second space (shared flow path), 63...Third space (shared flow path), 80, 80A...Controller

Claims

1. a casing having a peripheral wall; a plurality of heat exchangers arranged in parallel across the peripheral wall; a plurality of fans for supplying cooling air to the plurality of heat exchangers; A construction machine equipped with a controller that controls the rotation speed of the plurality of fans, the plurality of heat exchangers are classified into a plurality of groups, and each of the plurality of heat exchangers belongs to only one of the plurality of groups; each of the plurality of fans is arranged in association with only one of the plurality of groups; At least one fan is associated with each group of heat exchangers; a separation wall is disposed in the space surrounded by the peripheral wall so as to separate flow paths from each group of the heat exchangers to the corresponding fans; the plurality of groups includes a specific group configured to include adjacent heat exchangers, Two or more fans are associated with the particular group of heat exchangers; a first fan, which is one of the two or more fans associated with the specific group of the heat exchangers, is disposed on a boundary between a first heat exchanger and a second heat exchanger that belong to the specific group and are disposed adjacent to each other; The controller is configured to output a control command to rotate the first fan and the other fans associated with the specific group of the heat exchanger at the same rotation speed. Construction machinery characterized by:

2. The construction machine according to claim 1, The controller is configured to control the rotation speeds of two or more fans including the first fan associated with the specific group of the heat exchangers, in accordance with the temperature of a fluid flowing through a heat exchanger that has the largest amount of heat exchanged among the heat exchangers of the specific group. Construction machinery characterized by:

3. The construction machine according to claim 1, The controller is configured to control two or more fans, including the first fan, associated with the specific group of the heat exchanger so that the rotation speeds of the fans increase in unison when the fans are started. Construction machinery characterized by:

4. The construction machine according to claim 1, a flow path through which cooling air generated by two or more fans including the first fan associated with the specific group of the heat exchangers flows is partially partitioned by a partition wall extending from the heat exchanger side toward the fan side, the partition wall has an end portion on the heat exchanger side located on the boundary between the first heat exchanger and the second heat exchanger, and an end portion on the fan side located opposite the first fan, the partition wall has a notch at a portion facing the first fan at the end portion on the fan side, The first fan is disposed in the notch. Construction machinery characterized by:

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