JPH07127097A - Construction machine - Google Patents

Abstract

PURPOSE:To prevent operating oil from rising in the temperature by cooling an operating oil tank by cooling air. CONSTITUTION:Plural cooling fins 26, 26,... projecting outward are arranged on a left side surface of an operating oil tank 25, and a ventilation cover 27 is installed so as to cover the respective cooling fins 26 from outside. A cooling air passage 28 is formed between the ventilation cover 27 and the left side surface of the operating oil tank 25, and the cooling air passage 28 is communicated with the other outflow port 24A of a building cover 21. Cooling air sucked in a machine room 4 by a cooling fan 13 cools an engine 12 and a hydraulic pump 14, and flows in the arrow C direction into the cooling air passage 28 in the ventilation cover 27 from the other outflow port 24A of a left side cover part 24, and cools operating oil in the operating oil tank 25 through the respective cooling fins 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic excavator, and more particularly to a construction machine adapted to cool a hydraulic oil tank.

[0002]

2. Description of the Related Art FIGS. 8 to 10 show a hydraulic excavator as an example of a conventional construction machine.

In the figure, 1 is a lower traveling body, 2 is an upper revolving body mounted on the lower traveling body 1 so as to be rotatable,
The upper revolving structure 2 includes a revolving frame 3 as a frame.
And a machine room 4, a driver's cab 5, a counterweight 6 and the like provided on the revolving frame 3, and a working device 7 is provided on the front part of the revolving frame 3 so as to be able to move up and down. Here, various operating levers (not shown) are provided in the cab 5, and the working device 7 and the lower traveling body 1 are operated by operating these operating levers. Further, the counterweight 6 is the working device 7
Is provided to balance the upper swing body 2.

Reference numeral 8 denotes a building cover provided on the revolving frame 3 so as to define the machine room 4, and the building cover 8
Is an engine cover 9 which is centrally located so as to cover an upper portion of an engine 12 described later and is openable and closable, a right side cover portion 10 having an inverted L-shaped cross section which is provided on the right side of the engine cover 9, The left side cover portion 11 has an inverted L-shaped cross section and is provided on the left side of the left side portion 9. Here, on the upper surface of the right side cover portion 10, as shown in FIG. 9, an air inlet 10A made of a plurality of elongated holes formed by press working or the like is provided. Further, as shown in FIG. 8, an air outlet 9A made up of a plurality of elongated holes formed by press working is provided on the upper left side of the engine cover 9.

Reference numeral 12 denotes an engine which is located inside the building cover 8 and is provided on the revolving frame 3.
A cooling fan 13 that is rotationally driven by the engine 12 is provided on one end side of the.

Reference numerals 14 and 14 denote hydraulic pumps provided on the other end side of the engine 12. Each hydraulic pump 14 is rotationally driven by the engine 12, and a hydraulic oil tank 16 to be described later is provided.
10 is discharged as pressure oil into the pipe line 15 shown in FIG. 10, and the hydraulic motor for traveling and each hydraulic cylinder of the working device 7 (neither is shown) are discharged via a control valve 19 described later. ).

Reference numeral 16 denotes a hydraulic oil tank provided on the revolving frame 3 adjacent to the machine chamber 4. The hydraulic oil tank 16 is formed of a metal plate or the like into a rectangular can shape.
Hydraulic oil is stored inside.

Reference numerals 17 and 18 denote a cooling fan 13 and an inflow port 10.
A radiator and an oil cooler provided between the radiator 17 and A are shown. The radiator 17 and the oil cooler 18 are cooled by cooling air from the cooling fan 13, and the oil cooler 18 cools the hydraulic oil in the hydraulic oil tank 16. Then, the inflow port 10 of the building cover 8 is cooled by the cooling fan 13.
The air sucked from A circulates in the machine room 4 as cooling air, cools the radiator 17, the oil cooler 18, the engine 12, the hydraulic pump 14, etc., and then flows from the outlet 9A of the building cover 8 to the machine room 4 It leaks out.

Reference numeral 19 denotes a hydraulic pump 14 and a hydraulic oil tank 16.
Is a control valve provided in the middle of the pipe line 15 and the control valve 19 is switched by an operating lever in the operator's cab 5 so that the pressure oil from the pipe line 15 is transferred to a hydraulic motor and a hydraulic cylinder. And the like, and the lower traveling body 1 and the working device 7 are operated.

The hydraulic excavator according to the prior art has the above-mentioned structure, and when the engine 12 is in operation, the cooling fan 13 is rotated by the engine 12, so that
External air is sucked into the machine room 4 through the air inlet 10A, and this air is supplied to the oil cooler 18 and the radiator 1.
7, the engine 12, and the hydraulic pump 14 are cooled when flowing around, and are discharged to the outside of the machine chamber 4 from the outlet 9A.

[0011]

By the way, in the hydraulic excavator according to the above-mentioned conventional technique, the cooling air sucked into the machine chamber 4 by the cooling fan 13 is circulated around the oil cooler 18 so that the inside of the hydraulic oil tank 16 is closed. Since the operating oil is simply cooled, it is necessary to upsize the oil cooler 18 in order to improve the cooling performance of the operating oil, which causes a problem of cost increase. If the capacity of the oil cooler 18 is increased without changing the outer shape of the oil cooler 18 due to the layout and the like, the ventilation resistance of the cooling air by the cooling fan 13 may be increased, and the air volume of the cooling air is reduced, which is not always necessary. There is a problem that the hydraulic oil and cooling water cannot be cooled effectively.

Further, since the hydraulic oil tank 16 is exposed to the direct sunlight in the midsummer or the like, the cooling by the oil cooler 18 may not be sufficient, and there is a problem that the hydraulic oil becomes high in temperature.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention can cool the hydraulic oil in the hydraulic oil tank by utilizing cooling air, and can reduce the size of the oil cooler and the like. The purpose is to provide a construction machine.

[0014]

In order to solve the above-mentioned problems, in a construction machine according to the present invention, a machine cover is defined on a frame, and a building cover is provided with an air inlet and an air outlet, An engine and a radiator provided inside the building cover on the frame, and a cooling fan that is rotationally driven by the engine and causes the air sucked from the inlet to flow as cooling air around the radiator and the engine. A structure is provided adjacent to the machine room on a frame, and a hydraulic oil tank in which the hydraulic oil contained therein is cooled by an oil cooler in the building cover is adopted.

The features of the configuration adopted by the present invention are as follows:
In the hydraulic oil tank, a plurality of cooling fins projecting outward from the surface side of the hydraulic oil tank and the cooling fins are covered from the outside, and cooling is performed between the cooling fins and the surface of the hydraulic oil tank. There is provided a ventilation cover forming an air passage, and the cooling air passage by the ventilation cover is communicated with the inflow port or the outflow port of the building cover.

Further, the operating oil tank may be provided with an opening / closing door for selectively connecting and disconnecting the cooling air passage to the inflow port or the outflow port of the building cover.

[0017]

With the above structure, the cooling air flowing through the machine chamber can be circulated in the cooling air passage formed by the ventilation cover formed between the cooling fins on the surface side of the hydraulic oil tank. The hydraulic oil in the hydraulic oil tank can be continuously cooled via the cooling fins. Further, the ventilation cover can prevent the hydraulic oil tank from being exposed to direct sunlight, and the cooling air passage can provide heat insulation.

Further, if an opening / closing door is provided so that the cooling air passage is selectively communicated with or cut off from the inflow port or outflow port of the building cover, the temperature of the hydraulic oil may be lowered, for example, in cold regions. In this case, the flow of the cooling air to the cooling air passage can be stopped, and the temperature of the hydraulic oil can be adjusted according to the opening degree of the opening / closing door.

[0019]

Embodiments of the present invention will be described in detail below with reference to FIGS. The same components as those of the above-mentioned conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

1 to 4 show a first embodiment of the present invention.

In the figure, 21 indicates a building cover used in this embodiment, and the building cover 21 is an engine cover 22 (see FIG. 2).
(See above) and a right side cover portion 23 and a left side cover portion 24 having an inverted L-shaped cross section, which are substantially the same as the building cover 8 described in the related art. 23A is formed. An air outlet 22A is formed on the upper left side of the engine cover 22 as shown in FIG. 2, and the front end of the left cover 24 is shown in FIG.
As shown in FIG. 5, it serves as another outlet 24A that communicates with the ventilation cover 27 described later.

Reference numeral 25 denotes a box-shaped hydraulic oil tank provided in front of the machine chamber 4 on the swivel frame 3, and the hydraulic oil tank 25 is substantially the same as the hydraulic oil tank 16 described in the prior art. Although it is formed in the shape of a square can,
On the left side surface of the hydraulic oil tank 25, as shown in FIG. 3, a plurality of cooling fins 26, 26, ...

Reference numeral 27 denotes a ventilation cover provided on the hydraulic oil tank 25 so as to cover the respective cooling fins 26 of the hydraulic oil tank 25 from the outside, and the ventilation cover 27 is bent and formed in an inverted L shape. A cooling air passage 28 is formed between the ventilation cover 27 and the left side surface of the hydraulic oil tank 25.

Here, the ventilation cover 27 is attached together with the hydraulic oil tank 25 on the revolving frame 3 so that the left side surface thereof is flush with the left side cover portion 24, as shown in FIG.
The cooling air passage 28 communicates with the other outlet 24A. In addition, as shown in FIG.
As shown in FIG. 2, a guide rail portion 2 for an opening / closing door 31 described later
9 and 30 are provided, and the guide rail portions 29 and 30 are fixed to the upper and lower ends of the hydraulic oil tank 25 and extend in the left-right direction.

Reference numeral 31 denotes an opening / closing door slidably attached to the rear end side of the hydraulic oil tank 25 via upper and lower guide rail portions 29, 30. The opening / closing door 31 is connected to the other outlet 24A. It is located between the cooling air passages 28 and is slid along the guide rail portions 29 and 30 in the directions of arrows A and B in FIG. When the opening / closing door 31 is moved in the arrow A direction, the cooling air passage 28 is blocked from the outlet 24A, and when the opening / closing door 31 is moved in the arrow B direction, the cooling air passage 28 is opened. To communicate with the outlet 24A.

The hydraulic excavator according to this embodiment has the structure described above, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, the hydraulic oil tank 25
A plurality of cooling fins 26, 2 protruding outward on the left side surface of the
6, and a ventilation cover 27 is attached so as to cover each cooling fin 26 from the outside.
Between the cooling fin 26 and the right side surface of the hydraulic oil tank 25.
Since the cooling air passage 28 is formed through the above and the cooling air passage 28 is communicated with the other outlet 24A of the building cover 21, the following actions and effects are achieved.

That is, the cooling air sucked into the machine room 4 by the cooling fan 13 flows in the direction indicated by the arrow C in FIGS. 1 and 2, and the oil cooler 18, the radiator 17, the engine 12, the hydraulic pump 14 are provided. After cooling the engine, a part of this cooling air is discharged to the outside from the outlet 22A provided in the engine cover 22.

Then, the remaining cooling air flows to the left side cover portion 24.
From the other outlet 24A into the cooling air passage 28 in the ventilation cover 27 in the direction of the arrow C, and when flowing around the cooling fins 26, the inside of the hydraulic oil tank 25 passes through the cooling fins 26. Cool the hydraulic oil.

Therefore, according to this embodiment, the cooling efficiency can be greatly improved as compared with the case where the operating oil is cooled only by the oil cooler 18, and the oil cooler 18 can be made smaller than the conventional product. At the same time, the ventilation resistance of the oil cooler 18 can be reduced, and the amount of cooling air from the cooling fan 13 can be increased. Further, since the ventilation resistance can be reduced by downsizing the oil cooler 18, the flow of the cooling air by the cooling fan 13 can be made smooth, and the noise can be reduced.

Further, the ventilation cover 2 for the hydraulic oil tank 25 is provided.
7 so that the cooling air can be circulated in the cooling air passage 28, even when the operating oil tank 25 is exposed to direct sunlight, the ventilation cover 27 and the operating oil tank 25 are used.
It is possible to prevent heat from being accumulated during the operation and effectively suppress the temperature rise of the hydraulic oil.

On the other hand, a cooling air passage 28 is provided by providing an opening / closing door 31.
Is configured to selectively communicate with and cut off from the outlet 24A of the building cover 21, for example, when performing warm-up operation in use in a cold region, the opening / closing door 31 is closed to the cooling air passage 28. By stopping the circulation of the cooling air, it is possible to prevent the hydraulic oil from being in a supercooled state, and by adjusting the opening degree of the opening / closing door 31, the air volume of the cooling air can be appropriately adjusted. .

Next, FIG. 5 shows a second embodiment of the present invention, which is characterized in that cooling fins are provided on the side surface and the lower surface side of the hydraulic oil tank. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals,
The description is omitted.

In the figure, reference numeral 41 denotes a hydraulic oil tank used in this embodiment, and the hydraulic oil tank 41 is formed in a rectangular can shape similar to the hydraulic oil tank 25 described in the first embodiment. However, the hydraulic oil tank 41 is provided with a plurality of cooling fins 42, 42, ... On the right side surface shown in FIG. 5, and further on the lower side surface, cooling fins 43, 43, which are substantially similar to the respective cooling fins 42. A large number of ... Are formed to project.

Reference numeral 44 denotes a ventilation cover provided on the side surface of the hydraulic oil tank 41 so as to cover the cooling fins 42 of the hydraulic oil tank 41 from the outside, and the ventilation cover 44 is bent in an inverted L shape. A cooling air passage 45 is formed between the ventilation cover 44 and the side surface of the hydraulic oil tank 41.

Reference numeral 46 denotes another ventilation cover. The ventilation cover 46 is bent into an L shape similar to the ventilation cover 44 and covers the cooling fins 43 on the lower surface of the hydraulic oil tank 41. Is installed. Another cooling air passage 47 is formed between the ventilation cover 46 and the lower surface of the hydraulic oil tank 41. The ventilation covers 44 and 46 are attached together with the hydraulic oil tank 41 on the swivel frame 3 so that the left side cover portion 24 of the building cover 21 and the outside surface of the ventilation cover 44 are flush with each other, and the cooling air passages 45, 47 is another outlet 24 of the building cover 21
It is designed to communicate with A.

According to the present embodiment constructed as described above, substantially the same operational effects as the first embodiment can be obtained, but in particular, in this embodiment, the lower surface in which the working oil is stored in the working oil tank 41. Since a large number of cooling fins 43 are provided on the side as well, the contact area between the hydraulic oil and the cooling air is adjusted to the respective cooling fins 4.
2, 43 to increase the efficiency of cooling the hydraulic oil.

Next, FIG. 6 shows a third embodiment of the present invention. The feature of this embodiment is that cooling fins are provided on the side surface, the lower surface side and the upper surface side of the hydraulic oil tank. Also in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 51 denotes a hydraulic oil tank used in this embodiment. The hydraulic oil tank 51 is formed in a square can shape similar to the hydraulic oil tank 25 described in the first embodiment. A plurality of cooling fins 52, 52, ... Are provided on the right side surface of the hydraulic oil tank 51 shown in FIG. 6, and cooling fins 53, 53, which are substantially similar to the respective cooling fins 52, are provided on the lower side surface.
A large number of ... Are formed to project. Also, the hydraulic oil tank 5
Cooling fins 54, 54, ... Which are substantially similar to the respective cooling fins 53 are provided on the upper side surface of the No. 1.

Reference numeral 55 denotes a first ventilation cover provided on the side surface of the hydraulic oil tank 51 so as to cover each cooling fin 52 of the hydraulic oil tank 51 from the outside, and the ventilation cover 55 has an inverted L shape. A bent cooling air passage 56 is formed between the ventilation cover 55 and the left side surface of the hydraulic oil tank 51.

Reference numeral 57 denotes a second ventilation cover, which is bent into an L shape similar to the ventilation cover 55 and covers the cooling fins 53 on the lower surface of the hydraulic oil tank 51. Is installed in this way. Also,
A second cooling air passage 58 is formed between the ventilation cover 57 and the bottom side surface of the hydraulic oil tank 51.

Reference numeral 59 denotes a third ventilation cover, which is bent into an L shape similar to the ventilation cover 57 and covers the cooling fins 54 on the upper side surface of the hydraulic oil tank 51. Is installed in this way. Also,
A third cooling air passage 60 is formed between the ventilation cover 59 and the bottom side surface of the hydraulic oil tank 51.

The ventilation covers 55, 57, 59
Is the left cover portion 24 of the building cover 21 and the ventilation cover 5
5, 59 are mounted together with the hydraulic oil tank 51 on the swivel frame 3 such that the cooling air passages 56, 5 are flush with each other.
8, 60 communicate with another outlet 24A of the building cover 21.

According to the present embodiment constructed as described above, substantially the same operational effects as those of the first and second embodiments can be obtained. However, particularly in the present embodiment, the right side surface of the hydraulic oil tank 51, the upper side, Provide a plurality of cooling fins 52 to 54 on the lower surface,
The cooling fins 52 to 54 are connected to the ventilation covers 55, 57,
59, the hydraulic oil tank 51 and the ventilation covers 55, 5
Cooling air passages 56, 58, 60 formed between 7, 59
Is connected to the other outflow port 24A of the building cover 21, and the cooling air is circulated. Therefore, the working oil in the working oil tank 51 can be cooled from the three sides of the working oil tank 51 by the cooling air. It is possible to further improve the cooling efficiency of the hydraulic oil.

Next, FIG. 7 shows a fourth embodiment of the present invention, which is characterized in that the cooling air passage is provided so as to communicate with the inlet of the building cover. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 71 denotes a building cover used in this embodiment, and the building cover 71 occupies the central portion of the building cover 71 almost in the same manner as the engine cover 22 described in the first embodiment. The engine cover (not shown) in which the outflow port is formed and a right cover part 72 and a left cover part 73, which respectively constitute the right and left parts of the building cover 71, are roughly configured. An air inlet 72A formed of a plurality of elongated holes is provided. Further, another inflow port 72B that communicates with a ventilation cover 76, which will be described later, is provided at the front end of the right cover portion 72.

Reference numeral 74 denotes a hydraulic oil tank provided on the swivel frame 3 so as to be adjacent to the right side cover portion 72 on the front side of the machine chamber 4, and the right side surface of the hydraulic oil tank 74 is
Similar to the cooling fins 26 described in the first embodiment, a plurality of outwardly projecting cooling fins 75, 75, ...
(Only one is shown) is provided extending in the front-rear direction.

Reference numeral 76 denotes a ventilation cover provided so as to cover each cooling fin 75 of the hydraulic oil tank 74 from the outside. As shown in FIG. 7, the ventilation cover 76 has a rear end side of the right side cover portion 72. It is formed wide so as to abut against the front side, and is mounted on the swivel frame 3 together with the hydraulic oil tank 74. A cooling air passage 77 is formed between the ventilation cover 76 and the right side surface of the hydraulic oil tank 74 so as to communicate with the other inlet 72B of the building cover 71.

Reference numeral 78 denotes an opening / closing door provided on the front side of the cooling air passage 77. The opening / closing door 78 has substantially the same structure as the opening / closing door 31 described in the first embodiment, and is normally opened. To be operated.

The hydraulic excavator according to the present embodiment is constructed as described above, and when the cooling fan 13 rotates, the outside air is sucked from the one inlet 72A of the right side cover portion 72 in the direction of the arrow D and the other inlets. Cooling air passage 7 communicating with 72B
Outside air flows into the building cover 71 from 7 as shown by the arrow E direction. Then, the cooling air merges and flows in the arrow F direction, cools the oil cooler 18, the radiator 17, the engine 12, and the hydraulic pump 14, and then is discharged to the outside from the outlet of the engine cover.

Thus, in this embodiment thus constructed, it is possible to obtain substantially the same effects as the first embodiment, but especially in this embodiment, the cooling air passage 77 is in the direction of arrow E. The hydraulic oil tank 74 is driven by the outside air flowing in.
Since the cooling oil can be cooled, the working oil tank 74 can be cooled with a low-temperature cooling air, and the cooling efficiency of the working oil can be improved.

On the other hand, when the hydraulic oil becomes too cold, such as when the hydraulic excavator is used in a cold region, the opening / closing door 78 is closed to operate the hydraulic excavator, thereby cooling the ventilation cover 76. No cooling air flows in the air passage 77,
Cooling of the hydraulic oil tank 74 can be suppressed.

In each of the above embodiments, the hydraulic excavator has been described as an example. However, the present invention is not limited to this, and can be applied to other construction machines such as a wheel type hydraulic excavator and a hydraulic crane.

[0054]

As described in detail above, according to the present invention, a plurality of cooling fins projecting outward from the surface side of the hydraulic oil tank and the cooling fins are covered from the outside in the hydraulic oil tank,
A ventilation cover for forming a cooling air passage is provided between each cooling fin and the surface of the hydraulic oil tank, and the cooling air passage by the ventilation cover is communicated with the inlet or the outlet of the building cover. Cooling air flowing in the machine room can be circulated in the cooling air passage by the ventilation cover formed between the surface of the tank and each cooling fan, and this cooling air allows the cooling air inside the hydraulic oil tank to pass through the cooling fins. The hydraulic oil can continue to cool. Also, the ventilation cover can prevent the hydraulic oil tank from being exposed to direct sunlight.
The cooling air passage can provide heat insulation.

Therefore, the cooling efficiency can be greatly improved as compared with the case where the operating oil is cooled only by the oil cooler, the oil cooler can be downsized as compared with the conventional product, and the ventilation resistance by the oil cooler can be reduced. It is possible to increase the flow rate of the cooling air by the cooling fan. Further, since the ventilation resistance can be reduced by downsizing the oil cooler, the flow of the cooling air by the cooling fan can be made smooth, and the noise can be reduced.

Further, even when the operating oil tank is exposed to direct sunlight, heat can be prevented from being trapped between the ventilation cover and the operating oil tank, and the temperature rise of the operating oil can be effectively suppressed.

Further, if an opening / closing door is provided so that the cooling air passage is selectively communicated with or cut off from the inlet or outlet of the building cover, the temperature of the hydraulic oil may be lowered, for example, in cold regions. In this case, the flow of the cooling air to the cooling air passage can be stopped, and the temperature of the hydraulic oil can be adjusted according to the opening degree of the opening / closing door.

[Brief description of drawings]

FIG. 1 is a top view showing a hydraulic excavator according to a first embodiment with an engine cover removed.

FIG. 2 is an enlarged sectional view taken along the line II-II in FIG.

FIG. 3 is a perspective view of a hydraulic oil tank used in the first embodiment.

4 is a rear view of FIG. 3 showing an enlarged view of a hydraulic oil tank, cooling fins, a ventilation cover, an opening / closing door and the like.

FIG. 5 is a perspective view of a hydraulic oil tank applied to a hydraulic excavator according to a second embodiment.

FIG. 6 is a perspective view of a hydraulic oil tank applied to a hydraulic excavator according to a third embodiment.

FIG. 7 is a top view showing a hydraulic excavator according to a fourth embodiment with an engine cover removed.

FIG. 8 is an overall view showing a hydraulic excavator according to a conventional technique.

9 is a top view showing the hydraulic excavator shown in FIG. 8 with an engine cover removed.

FIG. 10 is a hydraulic circuit diagram showing an engine, a hydraulic pump, an oil cooler, a hydraulic oil tank, and the like.

[Explanation of symbols]

3 Swing frame (frame) 4 Machine room 12 Engine 13 Cooling fan 17 Radiator 18 Oil cooler 21,71 Building cover 22A, 24A Outlet port 23A, 72A, 72B Inlet port 25, 41, 51, 74 Hydraulic oil tank 26, 42, 43,52,53,54,75 Cooling fin 27,44,55,76 Ventilation cover 28,45,47,56,58,60 Cooling air passage 31,78 Open / close door

Claims (2)

[Claims] 1. A building cover that defines a machine room on a frame and is provided with an air inlet and an air outlet, and an engine and a radiator that are located inside the building cover and are provided on the frame. Is driven to rotate by the engine,
A cooling fan for circulating the air sucked from the inlet as cooling air around the radiator and the engine,
In a construction machine provided with a hydraulic oil tank which is provided on a frame adjacent to the machine room and in which the hydraulic oil contained therein is cooled by an oil cooler in the building cover, the hydraulic oil tank includes: A plurality of cooling fins projecting outward from the surface side of the hydraulic oil tank, and a ventilation cover that covers each cooling fin from the outside and forms a cooling air passage between each cooling fin and the surface of the hydraulic oil tank. Is provided
A construction machine having a structure in which a cooling air passage provided by the ventilation cover communicates with an inflow port or an outflow port of the building cover. 2. The construction machine according to claim 1, wherein the hydraulic oil tank is provided with an opening / closing door that selectively connects and disconnects the cooling air passage to an inlet or an outlet of a building cover.