JP2019112902A - Construction machine - Google Patents

Abstract

To insulate a turbocharger and an exhaust pipe from heat while preventing a decrease in the temperature of exhaust gas circulating in the exhaust pipe.SOLUTION: A heat insulating cover 18 that covers a turbocharger 14 and a downstream exhaust pipe 11B is composed of a heat insulating plate 19, a discharge port 21 and a guide plate 22. The heat insulating plate 19 is provided so as to cover the circumference of the turbocharger 14 and the downstream exhaust pipe 11B, and includes an intake port 19A1 on an upstream side in the flowing direction of cooling air F. The discharge port 21 is formed in a position, in the heat insulating plate 19, corresponding to a connection part 14A1 between the turbocharger 14 and the downstream exhaust pipe 11B, and externally discharges the cooling air F introduced into the heat insulating plate 19 from the intake port 19A1. The guide plate 22 is provided in a position, on an inner peripheral surface 19C2 of the heat insulating plate 19, that faces the discharge port 21, and blocks the cooling air F flowing toward the downstream exhaust pipe 11B while guiding the cooling air F in the heat insulating plate 19 to the discharge port 21.SELECTED DRAWING: Figure 3

Description

  The present invention relates to, for example, a construction machine such as a hydraulic shovel provided with a heat shield cover on a turbocharger attached to an engine.

  Generally, a hydraulic shovel as a representative example of a construction machine is connected to an engine mounted on a self-propelled vehicle body, a cooling fan provided on the engine and sucking in cooling air toward the engine, and a base end connected to the engine And an exhaust pipe for introducing exhaust gas discharged from the engine to the outside, and a turbo attached to the middle of the exhaust pipe and using the exhaust gas discharged from the engine to supply air from the outside to the engine A turbocharger (supercharger), an exhaust gas post-treatment device provided at the tip of the exhaust pipe for purifying the exhaust gas, and the turbocharger for shielding heat generated from the turbocharger and the exhaust pipe And a heat shield cover that covers the outer circumference of the exhaust pipe. The exhaust pipe is divided into an upstream exhaust pipe located on the upstream side across the turbocharger and a downstream exhaust pipe located on the downstream side.

  A pipe of resin material, electrical components and the like are disposed around the turbocharger and the exhaust pipe. In addition, in small construction machines such as mini excavators, since the engine is disposed in a limited and narrow space, a turbocharger and an exhaust pipe are disposed near the driver's seat, or near a maintenance site such as an engine In some cases, a turbocharger and an exhaust pipe may be provided.

  Here, since the turbocharger attached to the engine supplies air to the intake side of the engine using exhaust gas discharged from the exhaust manifold of the engine, high temperature heat is generated by circulation of high temperature exhaust gas. Occur. Therefore, a heat shield cover is provided to cover the turbocharger and the exhaust pipe so that the heat of the turbocharger and the exhaust pipe does not affect the surroundings (for example, see Patent Document 1).

Unexamined-Japanese-Patent No. 9-158743

  By the way, an exhaust gas post-treatment device for purifying the exhaust gas is provided at the tip of the exhaust pipe. In this exhaust gas post-treatment device, particulate matter (PM) in the exhaust gas collected by the filter is burned using high temperature exhaust gas.

  In this case, in Patent Document 1, the cooling air sucked by the cooling fan flows between the heat shield cover and the turbocharger and the exhaust pipe, and the exhaust pipe is cooled. As a result, the temperature of the exhaust gas flowing in the exhaust pipe may decrease, which may reduce the purification efficiency of the exhaust gas post-treatment device.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to shield a turbocharger and an exhaust pipe and to suppress a temperature decrease of exhaust gas flowing in the exhaust pipe. It is about providing the equipped construction machine.

  The construction machine according to the present invention comprises an engine mounted on a self-propelled vehicle body, a cooling fan provided in the engine for sucking cooling air toward the engine, and a base end connected to the engine and discharged from the engine An exhaust pipe for guiding the exhaust gas to the outside, a turbocharger for supplying air from the outside to the engine by using the exhaust gas attached to the middle of the exhaust pipe and discharged from the engine; An exhaust gas post-treatment device provided at the tip of the exhaust gas for purifying the exhaust gas; and a heat shield for covering the outer periphery of the turbocharger and the exhaust pipe to shield the heat generated from the turbocharger and the exhaust pipe. A cover is provided, and the exhaust pipe is divided into an upstream exhaust pipe located on the upstream side across the turbocharger and a downstream exhaust pipe located on the downstream side. To have.

  The heat shield cover is provided to cover the outer periphery of the turbocharger and the downstream exhaust pipe, and has a heat shield plate having an inlet on the upstream side in the flow direction of the cooling air, and the heat shield plate among the heat shield plates. An outlet formed at a position corresponding to a connection portion between the turbocharger and the downstream exhaust pipe, for discharging the cooling air introduced into the heat shield from the inlet to the outside, and the inside of the heat shield It is provided at a position facing the discharge port on the peripheral surface, and is configured by a guide plate that blocks the cooling air flowing toward the downstream exhaust pipe and guides the cooling air in the heat shield to the discharge port. There is.

  According to the present invention, the heat shield of the heat shield cover can shield the turbocharger and the exhaust pipe from heat. Further, since the cooling air introduced into the heat shield is guided to the discharge port by the induction plate, the cooling air can be prevented from hitting the exhaust pipe, and the temperature decrease of the exhaust gas flowing in the exhaust pipe can be suppressed. can do.

It is a front view showing a hydraulic shovel concerning an embodiment of the present invention. It is a top view which shows the state in which the engine, the turbocharger, the exhaust gas post-processing apparatus, etc. were mounted in the turning frame. FIG. 2 is a perspective view showing an engine, an exhaust pipe, a turbocharger, a heat shield cover, an exhaust gas post-treatment device and the like. FIG. 4 is an exploded perspective view showing a state in which the heat shield cover is removed from the exhaust pipe and the turbocharger in FIG. 3. It is a front view which shows a heat shielding cover alone. FIG. 6 is a bottom view of the heat shielding cover as viewed in the direction of arrows VI-VI in FIG. 5. It is a rear view which saw the heat shielding cover from the back side. It is explanatory drawing which shows the flow state of the cooling air introduced in the heat insulation cover. It is the same perspective view as FIG. 3 which shows the state by which the heat insulation cover by the 1st modification of this invention was provided in the exhaust pipe and the heat insulation cover. It is a perspective view showing the revolving frame by the 2nd modification of the present invention, a counterweight, an engine, a turbocharger, a thermal insulation cover, etc. from the rear side. It is a disassembled perspective view which shows the heat insulation cover by the 3rd modification of this invention. It is explanatory drawing similar to FIG. 8 which shows the flow state of a cooling wind.

  Hereinafter, as a representative example of a construction machine according to an embodiment of the present invention, a crawler-type small hydraulic excavator, a so-called mini-excavator will be described as an example, and will be described according to the attached drawings.

  In FIG. 1, the hydraulic shovel 1 includes a self-propelled crawler type lower traveling unit 2, an upper revolving unit 3 rotatably mounted on the lower traveling unit 2, and front and rear directions of the upper revolving unit 3. It is provided on the front side so as to be movable up and down, and is configured to include a swing type work device 4 that performs excavation work and the like of earth and sand. The lower traveling body 2 and the upper swing body 3 constitute a vehicle body of the present invention. The upper swing body 3 is configured to include a swing frame 5, a counterweight 6, a cab 7, an engine 8, a turbocharger 14, an exhaust gas post-treatment device 17, a heat shield cover 18 and the like described later.

  The swing frame 5 is a support structure of the upper swing body 3 and is attached to the lower traveling body 2. The turning frame 5 is configured such that the entire shape is substantially circular in a plan view, so that at least the rear side substantially fits within the vehicle width when the turning operation is performed.

  As shown in FIG. 2, the turning frame 5 is a flat bottom plate 5A extending left and right in the left and right direction, and an upper surface side of the bottom plate 5A spaced apart in the left and right directions. Left vertical plate 5B and right vertical plate 5C, a support bracket 5D provided at the front end of each vertical plate 5B, 5C for pivotally supporting the work device 4, and left and right vertical Provided at the rear end of the plates 5B and 5C and extending in the left and right directions from the left and right vertical plates 5B and 5C at a distance from the left and right vertical plates 5B and 5C The left side frame 5F and the right side frame 5G are included.

  The counterweight 6 is provided on the rear side of the swing frame 5. The counterweight 6 balances the weight with the work device 4. The counterweight 6 extends in a substantially arc shape in the left and right directions at a position surrounding the engine 8 described later from the rear side.

  The cab 7 is mounted on the left front side of the swing frame 5. The cab 7 is formed as a box body extending upward and downward. The cab 7 is used by an operator, and a driver's seat 7A on which the operator is seated, an operation lever for traveling, an operation lever for operation (not shown), and the like are provided inside.

  The engine 8 is mounted on the rear side of the swing frame 5 in a horizontally disposed state extending in the left and right directions. As shown in FIG. 3, a cooling fan 8 </ b> A is provided on the right side of the engine 8. The cooling fan 8A is rotationally driven by the engine 8 to suck the cooling air F toward the engine 8 and supply the cooling air F to the heat exchange device 10 described later. On the other hand, a hydraulic pump 9 is provided on the left side of the engine 8. The hydraulic pump 9 is driven by the engine 8 to supply pressure oil to various hydraulic actuators.

  The heat exchange device 10 is disposed to face the right side of the cooling fan 8A. The heat exchange device 10 includes, for example, an oil cooler for cooling the hydraulic oil, a radiator for cooling the cooling water of the engine 8, an intercooler for cooling the air pressurized by the turbocharger 14, and the like.

  The exhaust pipe 11 is connected at its proximal end to the exhaust manifold 8B of the engine 8 and guides the exhaust gas discharged from the engine 8 to the outside. The exhaust pipe 11 is divided into an upstream exhaust pipe 11A located upstream with respect to a turbocharger 14 described later and a downstream exhaust pipe 11B located downstream. That is, the upstream exhaust pipe 11A is connected at its proximal end side to the exhaust manifold 8B of the engine 8 and is connected at its distal end side to the turbocharger 14. On the other hand, the downstream exhaust pipe 11B is connected at its proximal end side to the turbocharger 14 and at its distal end side to an exhaust gas post-treatment device 17 described later.

  On the upstream side of the downstream exhaust pipe 11B, two screw seats 12 are provided so as to be separated in the circumferential direction. On the other hand, on the downstream side of the downstream exhaust pipe 11B, two screw seats 13 are provided spaced apart in the circumferential direction. These screw seats 12 and 13 attach a heat shielding cover 18 described later, and are fixed to the outer peripheral side of the downstream exhaust pipe 11B by welding or the like, for example.

  The turbocharger 14 is mounted in the middle of the exhaust pipe 11. The turbocharger 14 increases engine power by supplying air from the outside into each cylinder of the engine 8 using exhaust gas discharged from the engine 8. The turbocharger 14 includes a turbine housing 14A in which a turbine (not shown) rotationally driven by exhaust gas is incorporated, and a compressor (not shown) directly connected to the turbine via a rotation shaft (not shown). And the compressor housing 14B.

  The turbine housing 14A is connected to the exhaust manifold 8B of the engine 8 via the upstream exhaust pipe 11A. Further, the turbine housing 14A is provided with a connection portion 14A1 to which the downstream exhaust pipe 11B is connected. Accordingly, since high temperature exhaust gas flows in the turbine housing 14A, the turbine housing 14A becomes hot while the engine 8 is in operation and immediately after the engine 8 is stopped. On the other hand, in the compressor housing 14B, the intake hose 15 is connected to the inlet of the outside air, and the introduced outside air is pressurized in the compressor housing 14B. The pressurized outside air is supplied from the supply hose 16 into the cylinders of the engine 8 through the intercooler of the heat exchange device 10.

  The exhaust gas post-treatment device 17 is provided at the tip of the exhaust pipe 11 (downstream exhaust pipe 11B). The exhaust gas post-treatment device 17 purifies the exhaust gas discharged from the engine 8. Specifically, an oxidation catalyst (not shown) is provided in the exhaust gas post-treatment device 17 and carbon monoxide (CO) contained in the exhaust gas by circulating the exhaust gas through the oxidation catalyst. And hydrocarbons (HC) and the like are removed by oxidation. Further, a filter (not shown) for collecting particulate matter (PM) in the exhaust gas is provided in the exhaust gas post-treatment device 17, and the particulate matter collected by this filter is a high temperature exhaust gas. Burned off by gas.

  Next, the heat insulating cover 18 covering the outer periphery of the turbocharger 14 and the exhaust pipe 11 will be described.

  The heat shield cover 18 is provided around the turbocharger 14 and the downstream exhaust pipe 11 B in order to block the heat generated by the turbocharger 14 and the exhaust pipe 11. The heat shield cover 18 extends along the turbocharger 14 and the downstream exhaust pipe 11B, and has a semicircular cross section so as to cover the upper periphery of the turbocharger 14 and the downstream exhaust pipe 11B and the outer periphery opposite to the engine 8. Is formed.

  As a result, the heat shield cover 18 suppresses the transfer of heat to the operator seated on the driver's seat 7A in the cab 7, the pipelines of the resin material disposed around, the electrical components and the like. Further, the heat shield cover 18 is provided so as not to contact the turbocharger 14 and the downstream exhaust pipe 11B, which become hot during maintenance work. Furthermore, the heat shield cover 18 prevents the cooling air F from contacting the downstream exhaust pipe 11B so that the exhaust gas in the downstream exhaust pipe 11B is not cooled by the cooling air F. The heat shield cover 18 is configured to include the heat shield plate 19, the discharge port 21, and the guide plate 22.

  The heat shield plate 19 covers the outer periphery of the turbocharger 14 and the downstream exhaust pipe 11B. As shown in FIGS. 5 to 7, the heat shield plate 19 is directed from the turbocharger covering portion 19A covering the outer periphery of a part of the turbocharger 14 (turbine housing 14A), and from the turbocharger covering portion 19A to the downstream exhaust pipe 11B. The diameter is gradually reduced, and an exhaust port forming portion 19B in which an exhaust port 21 described later is formed is formed, and an exhaust pipe covering portion 19C extending along the downstream exhaust pipe 11B from the exhaust port forming portion 19B.

  The upstream side (right end side) of the flow direction of the cooling air F of the turbocharger covering portion 19A is an inlet 19A1 for taking the cooling air F into the turbocharger covering portion 19A. Further, in the turbocharger covering portion 19A, bolt through holes 19A4 penetrating from the outer peripheral surface 19A2 to the inner peripheral surface 19A3 are formed at positions corresponding to the screw seats 12, respectively. Further, in the exhaust pipe covering portion 19C, bolt through holes 19C3 penetrating from the outer peripheral surface 19C1 to the inner peripheral surface 19C2 are formed at positions corresponding to the screw seats 13, respectively. The heat shield cover 18 is attached by screwing the bolts 20 to the screw seats 12 and 13 via the bolt through holes 19A4 and 19C3, respectively.

  The exhaust port 21 is formed in the heat shield plate 19 at a position corresponding to the connection portion 14A1 between the turbine housing 14A of the turbocharger 14 and the downstream exhaust pipe 11B. That is, the discharge port 21 is formed in the discharge port forming portion 19 B of the heat shield plate 19. The discharge port 21 is formed as a slit penetrating from the outer peripheral surface 19B1 to the inner peripheral surface 19B2 of the discharge port forming portion 19B, and a plurality of (for example, three) slits are formed side by side in the left and right directions. The exhaust port 21 exhausts the cooling air F introduced from the inlet 19A1 into the turbocharger cover 19A of the heat shield plate 19 from the inside of the turbocharger cover 19A to the outside.

  The guide plate 22 is provided at a position facing the discharge port 21 in the inner peripheral surface 19C2 of the exhaust pipe covering portion 19C of the heat shield plate 19. The downstream portion of the induction plate 22 is attached to the exhaust pipe covering portion 19C at the position of the discharge port forming portion 19B, and the upstream portion becomes a free end toward the connection portion 14A1 of the downstream exhaust pipe 11B and the turbocharger 14 The diameter is reduced. Specifically, the induction plate 22 includes a mounting plate 22A attached to the inner circumferential surface 19C2 of the exhaust pipe covering 19C by welding or the like, and the tip of the mounting plate 22A between the turbine housing 14A and the downstream exhaust pipe 11B. It is comprised by the bending board part 22B bent toward connection area | region 14 A1. That is, in the induction plate 22, the mounting plate portion 22A is the downstream side portion in the flow direction of the cooling air F, and the bending plate portion 22B is the upstream side portion.

  The tip of the bent plate portion 22B is a free end, and is close to a connection portion 14A1 between the turbine housing 14A and the downstream exhaust pipe 11B. Thus, the cooling air F introduced into the turbocharger covering portion 19A is prevented from flowing toward the downstream exhaust pipe 11B by the bent plate portion 22B, and is directed to the discharge port 21 by the bent plate portion 22B. Led.

  As a result, the turbocharger 14 is cooled by the cooling air F, but the downstream exhaust pipe 11B is not cooled. Therefore, high temperature exhaust gas can be supplied to the exhaust gas post-treatment device 17, and the purification of the exhaust gas is efficient. It can be done well. In addition, the heat shield cover 18 can suppress the transfer of heat to the operator seated on the driver's seat 7A in the cab 7, the pipelines of resin material disposed around the periphery, electrical components, and the like. Further, the heat shield cover 18 can be protected not to contact the turbocharger 14 and the downstream exhaust pipe 11B, which become hot during the maintenance operation.

  The hydraulic shovel 1 according to the present embodiment has the above-described configuration. Next, the operation of the hydraulic shovel 1 will be described.

  First, the operator gets in the cab 7 and sits in the driver's seat 7A. By operating the operation lever and pedal (not shown) for traveling in this state, the lower traveling body 2 can be driven to move the hydraulic shovel 1 forward or backward. On the other hand, the operator sitting on the driver's seat 7A can operate the working device 4 and the like to carry out a digging operation of soil and the like by operating the operation control lever (not shown).

  In this case, the exhaust gas exhausted from the engine 8 is introduced from the exhaust manifold 8B into the exhaust gas post-treatment device 17 through the upstream exhaust pipe 11A, the turbocharger 14, and the downstream exhaust pipe 11B. Then, the exhaust gas introduced into the exhaust gas post-treatment device 17 flows through the oxidation catalyst and the filter (not shown) in the exhaust gas post-treatment device 17 and is purified. Particulate matter (PM) collected by the filter is burned and removed by the high temperature exhaust gas.

  Therefore, during the operation of the engine 8 and immediately after the stop of the engine 8, the turbine housing 14A of the turbocharger 14 and the exhaust pipe 11 become hot. In this case, the turbine housing 14A of the turbocharger 14 and the downstream exhaust pipe 11B are covered by the heat shield plate 19 of the heat shield cover 18. Therefore, the heat generated in the turbine housing 14A and the exhaust pipe 11 (downstream exhaust pipe 11B) is blocked by the heat shield plate 19 of the heat shield cover 18.

  Further, when the hydraulic shovel 1 is in operation, the cooling fan 8A is rotationally driven by the engine 8, and the cooling air F flows from the heat exchange device 10 side to the exhaust gas post-treatment device 17 side. In this case, when the exhaust gas flowing in the downstream exhaust pipe 11B is cooled by the cooling air F, the purification efficiency of the exhaust gas after the exhaust gas post-treatment device 17 may be reduced.

  Therefore, the cooling air F introduced into the heat shield plate 19 of the heat shield cover 18 is prevented from flowing toward the downstream exhaust pipe 11 B by the induction plate 22 and is guided to the discharge port 21. As a result, the cooling air F does not come in contact with the downstream exhaust pipe 11B (does not come in contact), so a high temperature exhaust gas is introduced into the exhaust gas post-treatment device 17 to reduce the exhaust gas purification efficiency. Can be suppressed.

  Thus, the hydraulic shovel 1 according to the present embodiment includes the engine 8 attached to the self-propelled vehicle body (the upper swing body 3), and the cooling fan 8A provided on the engine 8 and sucking the cooling air F toward the engine 8 And an exhaust pipe 11 having a base end connected to the engine 8 for guiding the exhaust gas discharged from the engine 8 to the outside, and the exhaust gas attached to the middle of the exhaust pipe 11 and discharged from the engine 8 A turbocharger 14 for supplying air from the outside to the engine 8, an exhaust gas post-treatment device 17 provided at the end of the exhaust pipe 11 for purifying the exhaust gas, the turbocharger 14 and the exhaust pipe A heat shield cover 18 covering the outer periphery of the turbocharger 14 and the exhaust pipe 11 to shield the heat generated from the heat pipe 11; Includes an upstream exhaust pipe 11A located on the upstream side across the turbocharger 14, is divided into a downstream exhaust pipe 11B located on the downstream side.

  The heat shield cover 18 is provided so as to cover the outer periphery of the turbocharger 14 and the downstream exhaust pipe 11B, and has a heat shield plate 19 having an inlet 19A1 on the upstream side in the flow direction of the cooling air F; It is formed in the position corresponding to connection part 14A1 of the heat shield plate 19 with the said turbocharger 14 and the said downstream exhaust pipe 11B, and the said cooling wind F introduced in the said heat shield plate 19 from the said inlet 19A1 is exterior And the inner peripheral surface 19C2 of the heat shield plate 19 at a position facing the discharge port 21 to block the cooling air F directed to the downstream exhaust pipe 11B and A guide plate 22 for guiding the cooling air F in the plate 19 to the discharge port 21 is formed.

  The heat shield cover 18 is formed integrally with the heat shield plate 19 and the guide plate 22. Further, the heat shield plate 19 of the heat shield cover 18 covers a part (turbine housing 14A) of the turbocharger 14 and the downstream exhaust pipe 11B.

  The heat shield plate 19 of the heat shield cover 18 is a turbocharger covering portion 19A covering a part of the turbocharger 14 (turbine housing 14A), and the downstream side of the exhaust pipe 11 from the turbocharger covering portion 19A. A discharge port forming portion 19B in which the discharge port 21 is formed by gradually reducing the diameter toward the exhaust pipe 11B, and an exhaust pipe covering portion 19C extending along the downstream exhaust pipe 11B from the discharge port forming portion 19B The downstream side portion of the induction plate 22 of the heat shield cover 18 is attached to the exhaust pipe covering portion 19C at the position of the discharge port forming portion 19B, and the upstream side portion becomes a free end, the downstream exhaust pipe The diameter is reduced toward the connection portion 14A1 between 11B and the turbocharger 14.

  As a result, heat transfer to the operator seated in the driver's seat 7A in the cab 7 can be blocked by the heat shield plate 19 of the heat shield cover 18, so that a good working environment can be maintained. In addition, the heat transmission to the turbocharger 14 and the other components disposed around the exhaust pipe 11 can be blocked, so that the influence of the heat on the other components can be reduced. In addition, when performing maintenance work for the engine 8 and the like, the heat shield plate 19 covers the turbocharger 14 and the exhaust pipe 11 which have become hot, thereby protecting the turbocharger 14 and the exhaust pipe 11 from being in contact with the work. can do.

  Furthermore, the cooling air F introduced into the heat shield plate 19 from the inlet 19A1 of the heat shield plate 19 is blocked by the induction plate 22 from flowing toward the downstream exhaust pipe 11B after the turbocharger 14 is cooled. And the discharge port 21. As a result, it is possible to prevent the turbocharger 14 from becoming excessively hot and, at the same time, the cooling air F does not contact the downstream exhaust pipe 11B, so introducing high temperature exhaust gas into the exhaust gas post-treatment device 17 And the purification efficiency of the exhaust gas can be improved.

  In the embodiment described above, the case where the outer periphery of the turbocharger 14 and the downstream exhaust pipe 11B is covered with the heat shielding cover 18 has been described as an example. However, the present invention is not limited to this. For example, as in a first modification shown in FIG. 9, the heat shield cover 31 may cover a part of the exhaust gas post-treatment device 17.

  That is, the heat shield cover 31 extends from the exhaust pipe covering portion 19C of the heat shield plate 19 toward the exhaust gas post-treatment device 17, and covers the upstream side of the exhaust gas post-treatment device 17 in the flow direction of the exhaust gas. A device cover 32 may be provided. Thus, the cooling air F can be prevented from coming into contact with the downstream exhaust pipe 11B and the downstream side of the exhaust gas post-treatment device 17. Therefore, the temperature decrease of the exhaust gas introduced from the downstream exhaust pipe 11B to the exhaust gas post-treatment device 17 can be further reduced, and the exhaust gas can be purified efficiently.

  Moreover, in the embodiment mentioned above, the case where the heat insulation cover 18 was attached to the turbocharger 14 provided in the front side (cab 7 side) of the engine 8 was mentioned as the example, and was demonstrated. However, the present invention is not limited to this. For example, as in the second modification shown in FIG. 10, the heat shield cover 18 may be attached to the turbocharger 14 provided on the rear side (counterweight 6 side) of the engine 8 Good. The same applies to the first modification.

  In the embodiment described above, the case where the heat shield cover 18 is formed in a semicircular arc shape in cross section so as to cover the upper side of the turbocharger 14 and the downstream exhaust pipe 11B and the outer periphery opposite to the engine 8 is taken as an example. I mentioned and explained. However, the present invention is not limited thereto. For example, as in the third modification shown in FIGS. 11 and 12, the heat shield cover 41 covers the heat shield plate 42 covering the turbocharger 14 and the entire circumference of the downstream exhaust pipe 11B. And, it may be constituted by the exhaust port 43 formed in the heat shield plate 42 and the induction plate 44 provided on the inner peripheral surface of the heat shield plate 42.

  Then, the heat shield plate 42 gradually reduces the diameter of the turbocharger cover portion 42A covering the turbocharger 14 from the turbocharger cover portion 42A toward the downstream exhaust pipe 11B, and the discharge port forming portion 42B in which the discharge port 43 is formed. And an exhaust pipe covering portion 42C extending along the downstream exhaust pipe 11B from the exhaust port forming portion 42B and covering the entire outer periphery of the downstream exhaust pipe 11B. The induction plate 44 is provided over the entire circumference on the inner peripheral side of the exhaust pipe covering portion 42C to block the cooling air F directed to the downstream exhaust pipe 11B, and also in the turbocharger covering portion 42A of the heat shield plate 42. The cooling air F is introduced to the outlet 43.

  In this case, the exhaust pipe covering portion 42C and the induction plate 44 include the one side induction plate 44A fixed to the one-side exhaust pipe covering portion 42C1 and the one side exhaust pipe covering portion 42C1, the other side exhaust pipe covering portion 42C2 and the other The other side induction plate 44B fixed to the side exhaust pipe covering portion 42C2 has a half divided shape. That is, in a state where the exhaust pipe covering portion 42C is attached to the downstream exhaust pipe 11B, a tubular body covering the entire circumference of the downstream exhaust pipe 11B by combining the one side exhaust pipe covering portion 42C1 and the other side exhaust pipe covering portion 42C2 It becomes. Further, the induction plate 44 is provided over the entire circumference of the downstream exhaust pipe 11B, and prevents the cooling air F introduced into the turbocharger covering portion 42A from flowing toward the downstream exhaust pipe 11B.

  Thus, the contact of the cooling air F with the downstream exhaust pipe 11B can be further reduced, so that the temperature decrease of the exhaust gas flowing in the downstream exhaust pipe 11B can be suppressed. As a result, the exhaust gas purification efficiency of the exhaust gas post-treatment device 17 can be further improved. Although the heat shield cover 41 is formed so as to cover only the downstream exhaust pipe 11B in the entire circumference, the turbocharger 14 may also be formed so as to cover the entire circumference. The same applies to the first and second modifications.

  In the embodiment described above, the case where the heat shield plate 19 of the heat shield cover 18 covers a part of the turbocharger 14 (the turbine housing 14A) has been described as an example. However, the present invention is not limited to this. For example, the heat shield plate 19 may be formed to cover both the turbine housing 14A and the compressor housing 14B of the turbocharger 14. The same applies to the first to third modifications.

  Further, in the embodiment described above, the hydraulic shovel 1 of a cab specification provided with a cab 7 that covers the upper side and the periphery of the driver's seat 7A has been described as an example. However, the present invention is not limited to this, and may be applied to, for example, a canopy-specific hydraulic shovel provided with a canopy covering the upper side of the driver's seat.

  Furthermore, in the embodiment described above, the small hydraulic excavator 1 as a construction machine, a so-called mini excavator, has been described as an example. However, the present invention is not limited to this, and can be widely applied to other construction machines such as, for example, wheeled hydraulic excavators and hydraulic cranes.

1 Hydraulic excavator (construction machine)
2 Lower body (body)
3 Upper revolving body (car body)
DESCRIPTION OF SYMBOLS 8 engine 8A cooling fan 11 exhaust pipe 11A upstream exhaust pipe 11B downstream exhaust pipe 14 turbocharger 14A turbine housing 14A1 connection part 17 exhaust gas post-treatment apparatus 18,31,41 thermal insulation cover 19,42 thermal insulation plate 19A, 42A turbocharger Cover portion 19A1 Intake port 19B, 42B Exhaust port formation portion 19C, 42C Exhaust pipe cover portion 19C2 Inner peripheral surface 21, 43 Exhaust port 22, 44 Induction plate F Cooling air flow

Claims (5)

An engine mounted on a self-propelled car body,
A cooling fan provided in the engine for drawing cooling air toward the engine;
An exhaust pipe having a proximal end connected to the engine and guiding exhaust gas exhausted from the engine to the outside;
A turbocharger for supplying air from the outside to the engine using the exhaust gas attached to the middle of the exhaust pipe and exhausted from the engine;
An exhaust gas post-treatment device provided at the tip of the exhaust pipe to purify the exhaust gas;
A heat shield cover is provided to cover the outer periphery of the turbocharger and the exhaust pipe to shield the heat generated from the turbocharger and the exhaust pipe.
In the construction machine, the exhaust pipe is divided into an upstream exhaust pipe located on the upstream side across the turbocharger and a downstream exhaust pipe located on the downstream side,
The heat shield cover is
A heat shield plate provided so as to cover the outer periphery of the turbocharger and the downstream exhaust pipe and having an inlet upstream of the flow direction of the cooling air;
An outlet formed at a position corresponding to a connection portion between the turbocharger and the downstream exhaust pipe in the heat shield plate, and discharging the cooling air introduced into the heat shield plate from the inlet to the outside; ,
It is provided in the position which counters the discharge port among the inner skins of the heat shield plate, and guides the cooling air in the heat shield plate to guide the cooling air in the heat shield plate to the discharge port while blocking the cooling air directed to the downstream exhaust pipe. A construction machine characterized by comprising a board.   2. The construction machine according to claim 1, wherein the heat shield cover is integrally formed with the heat shield plate and the induction plate.   The construction machine according to claim 1, wherein the heat shield plate of the heat shield cover covers a part of the turbocharger and the downstream exhaust pipe.   4. The construction machine according to claim 3, wherein the heat shield plate of the heat shield cover covers a part of the exhaust gas post-treatment device. The heat shield plate of the heat shield cover has a turbocharger covering portion covering a portion of the turbocharger, and a diameter gradually decreasing from the turbocharger covering portion toward the downstream exhaust pipe of the exhaust pipe, and the exhaust port And an exhaust pipe covering portion extending along the downstream exhaust pipe from the discharge port forming portion,
The induction plate of the heat shield cover has a downstream side portion attached to the exhaust pipe covering portion at a position of the discharge port forming portion, and an upstream side portion becomes a free end of the downstream exhaust pipe and the turbocharger. The construction machine according to claim 1, wherein the diameter is reduced toward the connection portion.

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