JP2004137883A - Turning working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compactly dispose an engine or muffler arranged in a turning body to improve cooling efficiency. <P>SOLUTION: In a turning working vehicle in which a working machine is mounted to a turning body constituted rotationally and an engine 34 is arranged in the bonnet 14 of the body rear part, a shielding plate 50 is placed at the back and forth direction in the bonnet 14. Openings 14b, 52 are provided at the side and the rear part of the body. Cooling wind is sucked from the side to hit the wind on the shielding plate 50 and discharge it from the rear part of the body. A muffler 40 is vertically set at the terminal end of the wind stream of the cooling air. The muffler 40 and the rear opening 52 are formed at one side of the shielding plate 50. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to the structure of an upper revolving structure such as a small turning type working vehicle with a reduced turning radius.

Conventionally, an attempt has been made to construct an upper revolving unit compactly in an excavation type turning work vehicle. For example, this is disclosed in Japanese Patent Application Laid-Open No. 11-303139. This is a small hydraulic excavator such as a small-slewing hydraulic excavator. The upper revolving structure is an intermediate strength member which is formed by orthogonally intersecting a pair of left and right front strength members erected in the upper revolving structure front-rear direction and a pair of vertical plates, and connected to a rear end of the vertical plates. And a front end of the horizontal plate, and a pair of left and right rear strength members erected in the front-rear direction, the intermediate strength member, and the rear strength member.

JP-A-11-303139

Various equipment such as an engine and a hydraulic pump, a hydraulic oil tank for hydraulic equipment, a radiator, a fuel tank and a battery are arranged inside the revolving structure of the turning work vehicle, and these are used to reduce the influence of heat from the engine. Considering this, it was difficult to arrange the revolving unit compactly in order to reduce the size.

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, according to the first aspect, in a turning work vehicle in which a working machine is attached to a turning body that is configured to be turnable and an engine 34 is disposed in a hood 14 at a rear portion of the turning body, the shielding plate 50 is disposed in the hood 14 in the front-rear direction. , And openings 14b and 52 are provided on the side and rear of the revolving superstructure, so that cooling air is sucked in from the side and applied to the shielding plate 50 to be discharged from the rear of the revolving superstructure.
According to a second aspect, a muffler 40 is vertically arranged at the end of the air passage of the cooling air.
In the third aspect, the muffler 40 and the rear opening 52 are provided on one side of the shielding plate 50.
According to a fourth aspect of the present invention, the battery 55 and the electrical components are arranged on the opposite side of the shield plate from the engine, and the engine 34 is separated from the battery 55 and the electrical components by the shield.
According to a fifth aspect, an air cleaner 41 is disposed at a rear portion of the air passage of the cooling air.
According to a sixth aspect, a muffler 40 is disposed in a space surrounded by the engine 34 and the rear surface of the arc-shaped frame 17.

The present invention has the following effects.
According to the first aspect of the present invention, the path of the cooling air is made long in the swirling body, so that the swirling body can be efficiently cooled.
In the second aspect, since the cooling air flows downward along the muffler, the cooling air can be discharged while cooling the muffler 40.
According to the third aspect, the muffler can be cooled by cooling air by separating the inside of the hood into right and left.
According to the fourth aspect, the battery and the electrical components can be separated from each other, so that the battery is not affected by water during cleaning.
According to the fifth aspect, the cooling air is discharged from the opening 52 along the air cleaner, and can be prevented from being exposed to the hot air from the lower muffler.
In the sixth aspect, the dead space formed at the rear of the arc-shaped frame 17 can be effectively used.

Next, an embodiment of the present invention will be described with reference to the drawings.
1 is an overall side view of the turning vehicle, FIG. 2 is a plan view thereof, FIG. 3 is a front view thereof, FIG. 4 is a rear view thereof, FIG. 5 is a side view showing a hood rotating structure, and FIG. FIG. 7 is a rear view, FIG. 8 is a left side view, FIG. 9 is a left side view of an engine showing a drive configuration of a fan, and FIG. FIG. 11 is a right side partial cross-sectional view showing the arrangement of the shielding plate.
12 is a side view showing the configuration of the shielding plate, FIG. 13 is a plan view of the same, FIG. 14 is a partial cross-sectional side view showing the bonnet support configuration, FIG. FIG. 16 is a partial cross-sectional view of the same side, and FIG. 17 is a side view showing the configuration of the right side of the hood.

The configuration of the turning work vehicle of the present invention will be described. This will be described with reference to FIGS.
The turning work vehicle supports a revolving body 2 at the upper center of the crawler-type traveling device 1 so as to be able to turn left and right, and a blade 3 is disposed at one of front and rear ends of the crawler-type traveling device 1 so as to be vertically rotatable. are doing.
A bonnet 14 for covering an engine or the like is disposed above the revolving superstructure 2, and a seat 16 is attached above the bonnet 14. In front of the seat 16, there is provided a driving operation unit 15 which is configured by arranging levers for performing driving operation and the like on a front column 19. A step 20 is arranged between the front column 19 and the bonnet 14 of the operation section 15.

A boom bracket 12 is attached to the front end of the revolving unit 2 so as to be rotatable left and right, and the lower end of the boom 6 is supported by the boom bracket 12 so as to be vertically rotatable.
The boom 6 is bent forward at an intermediate portion, and is formed in a substantially “C” shape having a bent portion 6d in a side view. An arm 5 is rotatably supported at an upper end of the boom 6, and a bucket 4 as a work attachment is rotatably supported at a tip of the arm 5. A working machine 7 is configured by the boom 6, the arm 5, the bucket 4, and the like.

The boom 6 is rotated by a boom cylinder 11, the arm 5 is rotated by an arm cylinder 10, and the bucket 4 is rotated by a bucket cylinder 9.
The boom cylinder 11, the arm cylinder 10, and the bucket cylinder 9 are configured as hydraulic cylinders. Each of the cylinders 9, 10, 11 supplies hydraulic oil from a hydraulic pump disposed in a bonnet 14 of the swivel 2 through a hydraulic hose. It is driven to expand and contract.

Further, the boom cylinder 11 is interposed between the cylinder support portion 12b of the boom bracket 12 and a boom cylinder bracket 36 provided on the front surface of the boom 6 at the middle, and the arm cylinder 10 is provided on the back surface of the boom 6 at the middle. The bucket cylinder 9 is interposed between the arm cylinder bottom bracket 31 and the bucket cylinder bracket 30 provided at the base end of the arm 5, and the bucket cylinder 9 is interposed between the bucket cylinder bracket 30 and the bucket bracket 29 connected to the bucket 4. Have been.

開口 An opening 31 is provided in the lower part of the revolving unit 2, and the cylinder rod of the swing cylinder 32 projects from the opening 31. The rear end of the swing cylinder 32 is rotatably supported by the frame 17 of the revolving unit 2. The tip of the cylinder rod of the swing cylinder 32 is connected to the boom bracket 12, and the boom bracket 12 is rotated left and right with respect to the revolving unit 2 by the swing cylinder 32.

The frame 17 is formed integrally with a counterweight at the rear part of the revolving superstructure 2. The frame 17 pivotally supports the boom bracket 12 at the front and forms a counterweight at the rear.
The boom bracket 12 is rotatably supported at the front of the frame 17. The central portion of the frame 17 constitutes a lower portion of the revolving structure 2 and connects a rear counterweight portion.

The revolving superstructure 2 is provided with a side opening 14b at a side portion, and a rear opening 52 and a lower opening 53 at a rear portion.
The side opening 14 b is provided on the left side of the hood 14. A radiator is provided inside the side opening 14b, and is cooled by air taken in from the side opening 14b.
The rear opening 52 is provided above the rear of the frame 17, and the lower opening 53 is provided at the lower rear of the frame 17. The air introduced through the side opening 14b is discharged from the revolving unit 2 through the rear opening 52 and the lower opening 53.

As shown in FIG. 5, the bonnet 14 provided on the revolving superstructure 2 is configured to be rotatable rearward.
The bonnet 14 is rotatably connected to the rear upper portion of the frame 17 at the lower rear portion. When the bonnet 14 is closed, the lower end of the bonnet 14 is locked by a locking tool or the like at a position where the lower end of the bonnet 14 abuts on the step 20, and is held in a closed state.
When the engine or the like is to be serviced, the locking tool and the like are released and the hood 14 is rotated rearward.

Next, a configuration inside the revolving superstructure 2 will be described with reference to FIGS.
A swivel joint 36 is connected to the center of the swing body 2, and a swing motor 37 is disposed near the swivel joint 36. The turning motor 37 is fixed to the frame 17.
An engine 34, a hydraulic pump 35, a swing cylinder 32, and a reservoir tank 43 are provided on the frame 17. Further, an oil filter 44 for hydraulic oil is provided in front of the reservoir tank 43, and a radiator 38 is provided above the reservoir tank 43. Further, a fuel tank 45 is provided above the swing cylinder 32, and a battery 55 is provided behind the fuel tank 45.

エ ン ジ ン The engine 34 provided inside the revolving superstructure 2 is provided on the frame 17 via a rubber mount or a rubber vibration isolator. A hydraulic pump 35 is connected to a side of the engine 34, and the hydraulic pump 35 is driven by the engine 34. The exhaust gas of the engine 34 is discharged outside the revolving unit 2 via a muffler 40 disposed behind the engine 34. The muffler 40 has an elliptical column shape, and is for introducing exhaust gas from above and discharging it downward.

In the revolving unit 2, the engine 34 has a crankshaft disposed in the left-right direction of the revolving unit 2, and a hydraulic pump 35 is connected to the crankshaft center of the engine 34.
The hydraulic pump 35 is connected to a swing cylinder 32, a swing motor 37, a swivel joint 36, a cylinder of the working machine 7, and the like via a hydraulic hose, a control valve in the front column 19, and the like.
The traveling device 1, the swing motor 37, the swing cylinder 32, the working machine 7, and the blade 3 are driven by a working oil discharged from a hydraulic pump 35 via a swivel joint 36.

A radiator 38 is provided on the side of the engine 34 opposite to the side to which the hydraulic pump 35 is connected, and a fan 39 is provided between the engine 34 and the radiator 38.
The fan 39 is fixed to a pulley 61 shown in FIG. 9, and the pulley 61 is connected to a pulley 63 that transmits a part of the driving force of the engine 34 via a belt 64. The pulley 61 is disposed above the engine 34. By driving the pulley 61, the fan 39 can be driven and cooling air can be introduced into the upper portion of the engine 34. A cylinder and an exhaust port are provided in the upper part of the engine 34, and the heating part of the engine 34 can be effectively cooled by cooling air introduced by the fan 39.

The radiator 38 is arranged on the side of the fan 39, and is arranged so that the position of the radiator 38 in a side view overlaps the position of the fan 39. That is, the radiator 38 is disposed immediately before the fan 39, and the distance from the radiator 38 to the engine 34 can be reduced.

Cooling water in the water jacket of the engine 34 is introduced into the radiator 38 via a hose or the like. Then, the cooling water introduced into the radiator 38 and cooled is returned into the water jacket of the engine 34 again.
The radiator 38 is disposed on the inside of the side surface of the revolving superstructure 2 so as to face outward. The fan 39 takes in outside air into the bonnet 14 to cool the radiator 38. The outside air introduced inside the bonnet 14 cools the radiator 38 and then cools the upper cylinder head of the engine 34.
The radiator 38 is disposed on the side of the fan 39 so that the position of the radiator 38 in a side view overlaps with the position of the fan 39, and the radiator 38 is disposed immediately before the fan 39. Thus, the distance from the radiator 38 to the engine 34 can be reduced.

A muffler 40 is provided at the rear of the engine 34, and the muffler 40 is connected to an exhaust port at the rear of the engine 34. The muffler 40 is disposed vertically in the revolving superstructure 2. Exhaust gas discharged from an exhaust port above the engine 34 is introduced from above the muffler 40 and discharged from below the muffler 40. The exhaust gas discharge portion of the muffler 40 coincides with the lower opening 53 provided at the lower rear portion of the frame 17, and the exhaust gas of the engine 34 passes through the lower opening 53 of the revolving unit 2 through the muffler 40. 2 is discharged outside.

An air cleaner 41 is disposed above the muffler 40, and an intake port 42 of the air cleaner 41 is disposed in the revolving unit 2 on a side opposite to a position where the radiator 38 is disposed. The air introduced into the air cleaner 41 through the intake port 42 is introduced into an intake port of the engine 34.

A reservoir tank 43 is disposed on the radiator 38 side of the revolving unit 2 in the front-rear direction of the revolving unit 2. The reservoir tank 43 stores the hydraulic oil of the hydraulic pump 35, and is connected to the hydraulic pump 35 by a hydraulic pipe.
The reservoir tank 43 is fixed on the frame 17, and a radiator 38 is provided on a rear upper surface of the reservoir tank 43. A step 20 is formed above the front part of the reservoir tank 43. An oil filter 44 is provided below the step 20 and in front of the reservoir tank 43.
The oil filter 44 is connected to the reservoir tank 43 and a control valve in the front column 19, and the hydraulic oil returning to the reservoir tank 43 via the control valve returns to the reservoir tank 43 via the oil filter 44. .

An oil supply port 43b extending upward is provided on the upper surface of the reservoir tank 43, so that hydraulic oil can be replenished from the oil supply port 43b.
The refueling port 43b of the reservoir tank 43 is disposed behind the step 20 and near the rising portion of the bonnet 14 in the revolving superstructure 2.
That is, the upper surface of the front part of the reservoir tank 43 has a shape along the lower surface of the step 20, and the fuel supply port 43 b is formed along the inner shape of the rising part formed in the front part of the bonnet 14.
The fuel supply port 43b of the reservoir tank 43 is located near the center of the bonnet 14 at the arrangement height. Thus, dust on the step 20 does not enter the oil supply port 43b. Further, when replenishing the working oil, the labor of the operator can be reduced.

In the revolving superstructure 2, the reservoir tank 43, the radiator 38, the fuel tank 45, and the battery 55 are accommodated in the front and rear length of the engine 34. Accordingly, the internal structure of the revolving unit 2 can be made compact, and the mass can be concentrated at the rear part of the revolving unit 2. By extending the front portion of the reservoir tank 43 below the step 20, the capacity of the reservoir tank 43 can be increased, and the distance between the reservoir tank 43 and the control valve disposed in the front column 19 can be shortened. can do.
Similarly, by extending the front of the fuel tank 45 below the step 20, the capacity of the fuel tank 45 can be increased, and the fuel can be stored at a location remote from the engine 34.
Further, the engine 34, the reservoir tank 43, the radiator 38, the fuel tank 45, and the battery 55 are disposed in the hood, and the reservoir tank 43, the radiator 38, the fuel tank 45, and the battery 55 are located on the side of the revolving unit 2. And maintainability is improved.

Next, the arrangement of the fuel tank 45 and the swing cylinder 32 in the revolving unit 2 will be described.
The fuel tank 45 is provided on the revolving unit 2 on the opposite side of the reservoir tank 43. As shown in FIG. 10, the fuel tank 45 is formed in an L shape in a side view. The front surface of the fuel tank 45 has a shape along the step 20, and the rear surface of the fuel tank 45 has a shape along the rising portion of the bonnet 14.
The fuel supply port of the fuel tank 45 is provided on the upper surface of the fuel tank 45. The upper portion of the fuel tank 45 is disposed on the open side of the bonnet 14, and the bonnet 14 is configured to rotate backward and open. Therefore, when the bonnet 14 is opened, there is an obstacle above the filler port of the fuel tank 45. There is nothing, and the refueling operation can be performed easily.

In the bonnet 14, a shielding plate 50 is disposed on the side of the fuel tank 45 inside the revolving structure.
The shielding plate 50 is formed in a shape along the upper left side surface and the lower rear surface of the fuel tank 45. Thus, the shield plate 50 separates the engine 34 from the fuel tank 45. Further, the shielding plate 50 is configured to partition the inside of the hood 14 in the longitudinal direction of the machine above the right end of the hydraulic pump 35. The shielding plate 50 is fixed to the frame 17 with bolts or the like.

The fuel tank 45 is fixed to the frame 17 by a stay or the like, and the swing cylinder 32 is disposed below the fuel tank 45.
A pivot 46 is inserted into the rear end of the swing cylinder 32, and the swing cylinder 32 is configured to be rotatable about the pivot 46. The lower end and the upper end of the pivot 46 are inserted and fixed in holes provided in the frame 17.
The tip of the cylinder rod of the swing cylinder 32 is connected to the boom bracket 12, and the swing cylinder 32 rotates the boom bracket 12 in the left-right direction.

In the internal structure of the revolving superstructure 2, a radiator 38 is disposed on one of the left and right sides of the engine 34, and a fuel tank 45 is disposed on the other. A reservoir tank 43 is provided below the radiator 38, and a swing cylinder 32 is provided below the fuel tank 45.
The front part of the reservoir tank 43 and the front part of the fuel tank 45 are arranged below the step 20. Further, the rear or upper portion of the fuel tank 45 is configured along the inside of the rising portion of the bonnet 14.

Next, the configuration of the shielding plate 50 will be described.
As shown in FIG. 10, the shielding plate 50 is disposed in the hood 14. The rear of the shielding plate 50 is fixed to the rear of the frame 17, and the frame 17 is connected to the frame 17 via the battery stand 55 </ b> C and the stay 70. It is fixed to
Further, as shown in FIG. 11, the inside of the bonnet 14 is divided into a portion where the engine 34 is provided and a portion where the fuel tank 45 is provided, and is configured to cover the entire side surface inside the hood 14.

As shown in FIGS. 12 and 13, the shielding plate 50 includes a plate body 50a, a rear stay 50b, and a front stay 50f.
The plate body 50a is disposed in the front and rear direction in the bonnet 14, and the side surface is directed to the left and right direction. With this configuration, it is possible to configure a space that is separated on the left and right inside the hood. Thus, the devices affected by the engine can be arranged in a space separated from the engine. Since the hood is separated in the front-rear direction, the left and right side surfaces of the hood can be used, and there is little effect on the front part of the hood or the steps, so that the operability of the operator is not affected.
A rear stay 50b is connected to a rear right side surface of the plate 50a, and the rear stay 50b is formed in an inverted L-shape in a side view. A bolt hole is provided on the upper surface of the rear stay 50b, and is fixed to the rear portion of the frame 17 by a bolt or the like inserted into the bolt hole. Further, a rear end of the battery stand 55c is connected to a lower portion of the rear stay 50b.

A front stay 50f formed in a substantially L-shape in side view is fixedly provided at the center of the plate body 50a.
The front end of the battery stand 55c is connected to the center of the front stay 50f, and the battery stand 55c connected to the rear stay 50b and the front stay 50f is fixed to the rear inner side surface of the frame 17. Things.
A stay 70 is connected to the lower rear surface of the front stay 50f, and the lower end of the front stay 50f is fixed to the frame 17 by the stay 70.

The shielding plate 50 not only isolates the fuel tank 45 and the battery 55 from the engine 34 in the hood 14 but also serves as a support for the hood 14. When the hood 14 is closed, the lower surface of the hood 14 is supported by the shielding plate 50. Therefore, the support rigidity of the hood can be improved, the members for supporting the hood can be omitted, and the degree of freedom of the layout in the hood can be improved.
As shown in FIG. 14, a lower frame 81 of the bonnet 14 is fixedly provided on the inner lower surface of the bonnet 14, and a rotating plate 84 is fixedly provided at a rear portion of the lower frame 81. The rotating plate 84 is rotatably supported at its lower end by a stay 85 fixed to the frame 17.
With the configuration of the bonnet 14 described above, the bonnet 14 can be pivoted rearward with respect to the frame 17 and opened. Note that the amount of rotation of the hood 14 is regulated to a fixed amount by the locking member 83.

A contact portion 82 is fixed to the lower frame 81 of the bonnet 14, and the contact portion 82 is disposed in the longitudinal direction of the machine. The contact portion 82 comes into contact with the upper portion of the shielding plate 50 when the hood 14 is closed.
That is, when the bonnet 14 is closed, the lower frame 81 of the bonnet 14 contacts the shielding plate 50 via the contact portion 82. Thereby, the hood 14 is supported by the shielding plate 50.
In the closed state, the lower outer peripheral portion of the bonnet 14 abuts on the step 20, the side frame 60 and the rear portion of the frame 17, and is supported. The upper lower surface of the hood 14 is supported by the shielding plate 50. Therefore, the hood 14 can be stably supported.

Next, a configuration in which the flow of the cooling air is regulated by the shielding plate 50 will be described with reference to FIGS. 15 and 16.
In FIGS. 15 and 16, black arrows indicate the flow of wind.
As described above, outside air is introduced into the revolving unit 2 from the side opening 14b provided on the side surface of the hood 14, and is used as cooling air. By driving the fan 39, cooling air is supplied to the engine 34 through the side opening 14b and the radiator 38.
A shielding plate 50 is provided on a side of the engine 34, and the cooling air flows toward the rear of the revolving unit 2 by the shielding plate 50. The outside air passing through the engine 34 is discharged to the outside of the revolving unit 2 through the rear opening 52 and the lower opening 53 at the rear of the revolving unit 2. Therefore, the path of the cooling air can be lengthened in the turning body, and the turning body can be cooled efficiently. Since the cooling air discharged from the lower opening 53 flows downward along the muffler 40, the cooling air is discharged while cooling the muffler 40.

In the hood 14, the space separated from the engine 34 by the shielding plate 50 is configured not to be affected by the heat of the engine 34. A fuel tank 45 and a battery 55 are provided in a space of the bonnet 14 separated from the engine 34, and an intake port 42 of the air cleaner 41 is provided.
The fuel tank 45 and the battery 55 are separated by a front stay 50f of the shielding plate 50. Thereby, the battery 55 is hardly affected by the fuel. Further, the battery is not contaminated by the fuel, and the durability of the battery can be improved. Furthermore, since the electrical components and the battery that are easily affected by water are isolated in the hood, the cleanability of the hood can be improved.

The intake port 42 of the air cleaner 41 is disposed below the space isolated from the engine 34 and near the inner side surface of the frame 17 by the shielding plate 50, so that the engine is less affected by heat and is taken from the side of the hood. Air that is not affected by the heat of the air can be taken in. Since the hot air generated in the bonnet 14 moves upward, the air near the intake port 42 provided in the lower part of the space isolated from the engine 34 is hardly heated. In addition, a space that is not affected by the heat of the engine can be configured in a space above the intake port of the air cleaner, and a device such as a fuel tank, a battery, and a fuse that is frequently inspected can be disposed in the space. Thereby, maintainability is improved.
The frame 17 is integrally formed by casting. The front and rear portions of the frame 17 are exposed, and the frame near the intake port 42 is a portion that also serves as a counterweight. For this reason, the temperature of the frame 17 is small, and it is difficult for the frame 17 to warm. Thus, the air taken in through the intake port 42 disposed near the frame 17 is not easily affected by heat.

The intake port 42 of the air cleaner 41 extends below the battery 55 from below the shielding plate 50. In a space separated from the engine 34 in the bonnet 14, unheated air can be introduced into the engine 34 in order to suck air. Further, as shown in FIG. 17, by providing the opening 14 c in the bonnet 14 on the side of the fuel tank 45, the outside air introduced from the opening 14 c is introduced into the intake port 42 via the fuel tank 45. That is, outside air is supplied to the fuel tank 45, and the fuel tank 45 is not heated. The fuel tank can be cooled by the intake of the engine 34.
When the inside of the hood 14 is cleaned, the electrical components, the battery, and the intake port 42, which are easily affected by water, are isolated in the hood 14 by the shielding plate 50, so that the cleaning can be easily performed. it can.

1 is an overall side view of a turning work vehicle. FIG. FIG. FIG. The side view which shows a hood rotation structure. FIG. 3 is a plan view showing the internal structure of the revolving superstructure. FIG. FIG. FIG. 3 is a left side view of the engine showing a drive configuration of the fan. FIG. 4 is a right side partial cross-sectional view showing the internal structure of the revolving superstructure. FIG. 5 is a right side partial cross-sectional view showing an arrangement configuration of a shielding plate. FIG. 4 is a side view showing a configuration of a shielding plate. FIG. Partial side cross section showing the bonnet support configuration. FIG. 3 is a partial plan sectional view showing the flow of wind in the hood. FIG. The right side view of a bonnet.

Explanation of reference numerals

2 Revolving body 14 Bonnet 17 Frame 19 Front column 32 Swing cylinder 34 Engine 35 Hydraulic pump 36 Swivel joint 37 Rotating motor 38 Radiator 38b Radiator mount 39 Fan 40 Muffler 43 Reservoir tank 44 Oil filter 45 Fuel tank 50 Shield plate 55 Battery

Claims (6)

In a revolving work vehicle in which a work machine is mounted on a revolving body configured to be revolvable and an engine 34 is disposed in a bonnet 14 at the rear of the revolving body, a shielding plate 50 is disposed in the hood 14 in the front-rear direction, A turning work vehicle characterized in that openings 14b and 52 are provided in a portion and a rear portion, and cooling air is sucked in from the side, and is applied to a shielding plate 50 to be discharged from a rear portion of the turning body. The turning work vehicle according to claim 1, wherein a muffler (40) is vertically disposed at an end of the cooling air path. The turning work vehicle according to claim 1, wherein a muffler (40) and a rear opening (52) are provided on one side of the shielding plate (50). The turning work vehicle according to claim 1, wherein a battery 55 and an electric component are arranged on the side of the shield plate opposite to the engine, and the engine 34, the battery 55, and the electric component are arranged separately by the shield. The turning work vehicle according to claim 1, wherein an air cleaner (41) is disposed at a rear portion of the cooling air path. The turning work vehicle according to claim 1, wherein a muffler (40) is disposed in a space surrounded by the engine (34) and a rear surface of the arc-shaped frame (17).