JP2018135041A - Construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction machine which can inhibit powder dust from flowing into an exhaust pipe cover and enables the powder dust to be easily discharged even when the powder dust accumulates on an exhaust pipe.SOLUTION: An exhaust pipe cover 19 covering an exhaust pipe 18 includes: a cylindrical cover body 20 which is installed on an exterior cover 8 with the lower end side covering a periphery of the exhaust pipe 18 and exhausts an exhaust gas from the exhaust pipe 18 to the outside at the upper end side; a cooling air introduction port 23 which guides cooling air for cooling devices in a machine room 12, such as an engine 13 and a heat exchanger 16, to a space between the exhaust pipe 18 and the exhaust pipe cover 19; and a wind guide plate 24 for introducing the cooling air to the cooling air introduction port 23.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a construction machine such as a hydraulic excavator provided with an engine that discharges exhaust gas through an exhaust pipe, for example.

  In general, a hydraulic excavator as a typical example of a construction machine includes a vehicle body including a self-propelled lower traveling body and an upper revolving body mounted on the lower traveling body so as to be capable of swiveling. The front device is provided so as to be able to move up and down. Further, a counterweight for balancing the weight with the front device is provided behind the upper swing body.

  The upper swing body constituting the vehicle body has a machine room disposed on the front side of the counterweight and covered with an exterior cover, an engine disposed in the machine room, and exhaust gas discharged from the engine to the upper outside of the machine room. A leading exhaust pipe is provided.

  Here, in addition to excavation and transportation work of earth and sand, hydraulic excavators are operating at work sites in various environments including forests, inboards, and buildings. For example, timber is cut and collected at a forest work site. In addition, wood chips are collected and transported at the work site in the ship. In addition, at the work site in the building, metal scrap is dismantled and sorted. At these work sites, fine wood dust, dust, dust and other dusts rise, and dust accumulates on the upper revolving body and exhaust pipe.

  The upper rotating body includes a muffler through which engine exhaust gas is guided to the machine room. The muffler has an exhaust port for discharging the introduced exhaust gas toward the upper side of the upper swing body. The above-described exhaust pipe is provided on the upper surface cover of the exterior cover, located above the exhaust port. The exhaust pipe extends vertically upward from the exhaust port of the muffler through the upper surface cover. Further, the exhaust pipe is bent rearward at an external position protruding upward from the upper surface cover in order to exhaust the exhaust gas to the rear of the upper swing body, and the exhaust port opens rearward. As a result, at the work site where the dust rises, the raised dust may accumulate on the upper part of the exhaust pipe.

  On the other hand, hydraulic excavators often perform work while maintaining the engine output at the rated maximum output. For this reason, the exhaust pipe tends to become high temperature due to the heat generated by the engine. Moreover, in recent years, exhaust gas treatment devices are mounted on hydraulic excavators in accordance with exhaust gas regulations. In the exhaust gas treatment device, purification of harmful substances such as particulate matter (PM) and nitrogen oxide (NOx) is performed. For example, it is known that an exhaust gas treatment device burns and removes particulate matter, and at this time, the temperature in the muffler becomes a high temperature of 600 ° C. or more, for example. Therefore, the exhaust pipe is likely to become high temperature due to the heat of the muffler, and the temperature is close to 400 ° C. at the upper part of the exhaust pipe where the temperature is highest.

  For these reasons, if dust accumulates in the upper part of the exhaust pipe or if dust enters the muffler through the exhaust pipe, it is affected by the high heat described above. Therefore, some hydraulic excavators are provided with an exhaust pipe cover on the upper side of the exterior cover so as to cover the front, left, right side and upper side of the exhaust pipe (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2015-117777

  By the way, in the thing by patent document 1, since the vent hole is provided in the upper part and side part of an exhaust pipe cover, dust will flow in into an exhaust pipe cover through these vent holes, and the exhaust pipe which becomes high temperature There is a problem that dust accumulates on the top of the wall. In particular, when the engine is stopped, the dust that has passed through the ventilation holes tends to accumulate on the exhaust pipe, and the dust that has accumulated on the exhaust pipe remains on the exhaust pipe even when the engine is started. It is affected by heat.

  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 prevent dust from flowing into the exhaust pipe cover and to easily discharge even when dust accumulates on the exhaust pipe. It is to provide a construction machine that can be used.

  The present invention has a self-propelled vehicle body provided with a front device at the front and a counterweight at the rear, and the vehicle body is disposed on the front side of the counterweight and covered with an exterior cover. And a construction machine comprising: an engine disposed in the machine room; an exhaust pipe that guides exhaust gas discharged from the engine to the upper outside of the machine room; and an exhaust pipe cover that covers the exhaust pipe. The exhaust pipe cover is installed on the exterior cover in a state where the lower end side covers the periphery of the exhaust pipe, and the upper end side is a cylindrical cover body that exhausts exhaust gas from the exhaust pipe to the outside, The cooling air that cools the device is configured by a cooling air introduction port that leads between the exhaust pipe and the exhaust pipe cover, and an air guide plate that introduces the cooling air into the cooling air introduction port. A.

  According to the present invention, dust can be prevented from flowing into the exhaust pipe cover, and dust can be easily discharged even when dust accumulates on the exhaust pipe.

1 is a front view showing a hydraulic excavator according to a first embodiment of the present invention. It is sectional drawing which looked at the machine room of the upper revolving body from the arrow II-II direction in FIG. It is a perspective view of the principal part expansion which shows a part of exterior cover, a muffler, an exhaust pipe, and an exhaust pipe cover. FIG. 4 is an enlarged cross-sectional view of a main part of a counterweight, an exterior cover, a muffler, an exhaust pipe, and an exhaust pipe cover as viewed from the direction of arrows IV-IV in FIG. 2. It is a disassembled perspective view in the state which decomposed | disassembled the upper surface cover of an exterior cover, an exhaust pipe, the cover main body of an exhaust pipe cover, and an air guide plate. It is a perspective view of the principal part expansion which shows the exhaust pipe cover by the 2nd Embodiment of this invention with a counterweight, an exterior cover, a muffler, and an exhaust pipe. It is a perspective view shown with the cover main body which permeate | transmitted the capture member.

  Hereinafter, as a representative example of a construction machine according to an embodiment of the present invention, a hydraulic excavator equipped with an engine will be taken as an example and described in detail with reference to the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. In FIG. 1, a hydraulic excavator 1 constitutes a crawler type construction machine. The hydraulic excavator 1 is a self-propelled crawler-type lower traveling body 2, an upper revolving body 3 that is mounted on the lower traveling body 2 so as to be capable of turning, and forms a vehicle body together with the lower traveling body 2, It is constituted by a front device 4 which is provided in front of the upper swing body 3 and in front of the rear direction so as to be capable of raising and lowering, and performs excavation work of earth and sand.

  The turning frame 5 forms a support structure for the upper turning body 3. As shown in FIG. 2, the revolving frame 5 is erected on a bottom plate 5A made of a thick steel plate or the like extending in the front and rear directions, and on the bottom plate 5A, and forward and rear with a predetermined interval in the left and right directions. Left vertical plate 5B, right vertical plate 5C, and left and right side frames 5D, 5E, which are arranged at intervals outside the left and right sides of each vertical plate 5B, 5C and extend forward and backward. A plurality of overhanging beams 5F (only two are shown in FIG. 2) projecting from the bottom plate 5A and the vertical plates 5B and 5C in the left and right directions, and supporting the left and right side frames 5D and 5E at the tip portions thereof. ) And a plurality of undercovers 5G forming a bottom surface between the vertical plates 5B and 5C and the side frames 5D and 5E.

  The revolving frame 5 closes the lower side of the machine room 12 described later. For example, the under cover 5G located between the left and right vertical plates 5B and 5C is provided with an outlet 5G1 for allowing the warm cooling air to flow out of the machine room 12 in the direction indicated by the arrow b. Yes.

  The counterweight 6 is provided at the rear part of the left and right vertical plates 5B and 5C forming the turning frame 5 (see FIG. 1). The counterweight 6 is in a weight balance with the front device 4 and is formed as a heavy object.

  The cab 7 is provided on the left front side of the revolving frame 5. The cab 7 is to be boarded by an operator. Inside the cab 7, for example, a driver's seat on which the operator is seated, a traveling operation lever, and a working operation lever (none of which are shown) are arranged. .

  The exterior cover 8 covers equipment including an engine 13, a muffler 14, a hydraulic pump 15, and a heat exchanger 16, which will be described later, and is provided on the revolving frame 5. The exterior cover 8 is provided between the counterweight 6 and the cab 7. Specifically, the exterior cover 8 is provided with a left frame 9 that rises from the left side frame 5D of the revolving frame 5 so as to cover the left side of the heat exchanger 16, and a revolving frame so as to cover the right side of the hydraulic pump 15 and the like. 5 and a top cover 11 extending horizontally between the upper part of the left cover 9 and the upper part of the right cover 10 so as to cover the upper side of the engine 13 and the like. It is comprised including. The left surface cover 9 is provided with a plurality of inflow ports 9A. As shown by an arrow a in FIG. 2, each inflow port 9 </ b> A allows outside air to flow into a machine chamber 12 described later as cooling air.

  The upper surface cover 11 is formed by combining a plurality of plates. An example of the combination will be described. The top cover 11 is located on the left side and covers the engine 13 and the upper side of the heat exchanger 16, and the muffler 14 described later is located on the right side of the engine cover part 11A. A muffler cover portion 11B that covers the upper side of the hydraulic pump 15 and a pump cover portion 11C that is positioned between the muffler cover portion 11B and the right surface cover 10 and covers the upper side of the hydraulic pump 15 are configured. At least a part of each cover 9, 10, 11 can be opened and closed so that maintenance of equipment located inside can be performed.

  Here, the muffler cover portion 11B constituting the upper surface cover 11 is formed as a flat plate-like body. The muffler cover portion 11B is located on the upstream side in the flow direction of the cooling air, and as shown by the arrow c in FIG. Is provided.

  The muffler cover portion 11B has an exhaust pipe insertion opening 11B2 at a position corresponding to an exhaust port 14C of the muffler 14 to be described later, that is, at a downstream side in the flow direction of the cooling air and at a rear position in the front and rear directions. Is formed. The exhaust pipe insertion opening 11B2 is formed as an octagonal opening, and, for example, four screw holes 11B3 are provided around the exhaust pipe insertion opening 11B2. The exhaust pipe insertion opening 11 </ b> B <b> 2 is larger than the exhaust pipe 18 described later, so that a cooling air inlet 23 described later can be formed between the exhaust pipe 18 and the exhaust pipe 18. The exhaust pipe insertion opening 11B2 may have a circular shape or the like in addition to the octagonal shape.

  Further, a cover body 20 described later is attached to the upper surface 11B4 of the muffler cover portion 11B around the exhaust pipe insertion opening 11B2. On the other hand, a later-described air guide plate 24 is attached to a lower surface 11B5 of the muffler cover portion 11B at a position corresponding to the exhaust pipe insertion opening 11B2.

  The machine room 12 is disposed on the front side of the counterweight 6. The machine room 12 is formed as a rectangular parallelepiped space elongated in the left and right directions, which is covered by the revolving frame 5 and the exterior cover 8. The machine room 12 includes a cooling air inflow chamber 12A located between the left cover 9 of the exterior cover 8 and the heat exchanger 16, an engine room 12B located between the heat exchanger 16 and the firewall 17, It is partitioned into a pump chamber 12C located between the firewall 17 and the right surface cover 10.

  The engine 13 is disposed in the engine room 12 </ b> B of the machine room 12. The engine 13 is provided on the rear side of the revolving frame 5 in a horizontally placed state extending in the left and right directions. A muffler 14 to be described later is provided on the upper right side of the engine 13 so as to be connected to an exhaust manifold (not shown) that discharges exhaust gas. A cooling fan 13 </ b> A is provided on the left side of the engine 13 at a position facing the heat exchanger 16. The cooling fan 13A is rotated by the engine 13 to circulate cooling air (outside air) from left to right in the machine room 12 as indicated by an arrow a in FIG. At this time, the engine cooling water, hydraulic oil, etc. can be cooled by circulating the cooling air through the heat exchanger 16.

  The muffler 14 processes exhaust gas discharged from the engine 13 and is provided at the upper right position of the engine 13. The muffler 14 is provided at a position above the hydraulic pump 15 so as to extend forward and backward. The muffler 14 includes a muffler case 14A formed as a cylindrical container extending in the front and rear directions, and an inflow port 14B projecting radially outward from the front position of the muffler case 14A toward the left side (see FIG. 4). And an exhaust port 14C provided to extend upward and downward at the rear position of the muffler case 14A. The inlet 14 </ b> B is connected to the exhaust manifold of the engine 13.

  Here, various processing devices (not shown) are accommodated in the muffler case 14A of the muffler 14. Specific treatment equipment includes particulate matter removal equipment composed of an oxidation catalyst and filter to collect and remove particulate matter (PM) contained in exhaust gas, nitrogen oxide contained in exhaust gas A NOx purification device that purifies (NOx) using an aqueous urea solution, a silencer (exhaust muffler) that reduces exhaust gas noise, and the like are known. The muffler case 14A is attached to the right side portion of the engine 13 together with the hydraulic pump 15 via a case attachment bracket 14D, for example.

  The exhaust port 14C of the muffler 14 extends through the muffler case 14A upward and downward (diameter direction), and is formed as a cylindrical body having a plurality of communication holes in an intermediate portion located in the muffler case 14A. ing. The upper part of the exhaust port 14 </ b> C protrudes toward the exhaust pipe insertion opening 11 </ b> B <b> 2 provided in the muffler cover part 11 </ b> B constituting the upper surface cover 11 of the exterior cover 8. Accordingly, as shown in FIGS. 2 and 4, the exhaust port 14 </ b> C is inserted into the exhaust pipe 18 described later from below. In this case, the exhaust port 14C provided in the vibration system on the engine 13 side is inserted with a predetermined gap so as not to interfere with the exhaust pipe 18 provided in the vibration system on the turning frame 5 side due to relative vibration. ing.

  The hydraulic pump 15 is provided on the right side portion of the engine 13 so as to be located in the pump chamber 12 </ b> C, and is driven by the engine 13. The hydraulic pump 15 discharges hydraulic oil supplied from a hydraulic oil tank 25 described later as pressure oil toward a control valve device (not shown).

  The heat exchanger 16 is located on the rear side of the cab 7 and is provided on the revolving frame 5. The heat exchanger 16 is positioned upstream of the cooling fan 13A with respect to the flow direction of the cooling air (flow direction from left to right), that is, between the left surface cover 9 and the cooling fan 13A. It is provided so as to face the fan 13A. The heat exchanger 16 includes, for example, a radiator that cools engine coolant, a cooler 16A that includes an oil cooler that cools hydraulic oil, and a frame member 16B that surrounds the cooler 16A. The heat exchanger 16 constitutes a partition member that partitions the left area of the machine room 12 into a cooling air inflow chamber 12A and an engine chamber 12B.

  The firewall 17 is located around the hydraulic pump 15 and is provided between the turning frame 5 and the upper surface cover 11 of the exterior cover 8. The firewall 17 blocks the engine 13, the muffler 14, and the hydraulic pump 15, and constitutes a partition member that partitions the right area of the machine room 12 into the engine room 12B and the pump room 12C. The firewall 17 is formed as a structure by, for example, bending a plurality of steel plates and fixing them together. The firewall 17 is formed so as to straddle the mounting base of the hydraulic pump 15 with respect to the engine 13. Thereby, the firewall 17 can prevent the leaked hydraulic oil from scattering to the engine 13 side even when the hydraulic oil leaks around the hydraulic pump 15.

  The exhaust pipe 18 guides the exhaust gas discharged from the engine 13 to the upper outside of the engine room 12B of the machine room 12. The exhaust pipe 18 is attached to the upper surface cover 11 of the exterior cover 8 via a wind guide plate 24 of the exhaust pipe cover 19 described later. As shown in FIG. 4, the exhaust pipe 18 has a larger diameter than the exhaust port 14 </ b> C of the muffler 14, and a cylindrical shape having a smaller diameter than the exhaust pipe insertion opening 11 </ b> B <b> 2 of the upper surface cover 11 and the vertical cover portion 20 </ b> A of the cover body 20 described later. The vertical cylindrical portion 18A extending upward and downward, and the inclined cylindrical portion 18B extending obliquely upward from the upper portion of the vertical cylindrical portion 18A toward the rear side. The opening of the inclined cylinder part 18B is formed obliquely with respect to the axis of the inclined cylinder part 18B so that the upper part protrudes backward from the lower part in order to suppress the inflow of dust.

  Next, the configuration of the exhaust pipe cover 19 that is a characteristic part of the present embodiment will be described in detail.

  The exhaust pipe cover 19 covers the exhaust pipe 18. The exhaust pipe cover 19 includes a cover body 20, a cooling air introduction port 23 and an air guide plate 24 which will be described later.

  The cover main body 20 is installed in the exterior cover 8 in a state where the lower end side covers the periphery of the exhaust pipe 18, and the upper end side discharges exhaust gas from the exhaust pipe 18 to the outside. As shown in FIGS. 4 and 5, the cover body 20 is formed as an octagonal cylindrical body that is the same as or slightly larger than the exhaust pipe insertion opening 11 </ b> B <b> 2 of the muffler cover portion 11 </ b> B constituting the upper surface cover 11 of the exterior cover 8. The vertical cover portion 20A extending in the direction, the inclined cover portion 20B extending obliquely upward from the upper portion of the vertical cover portion 20A to the rear side, and the mounting plate portion 20C formed in a flange shape at the lower end portion of the vertical cover portion 20A It is comprised by. The mounting plate portion 20C is formed as a rectangular plate that covers the exhaust pipe insertion opening 11B2 and the four screw holes 11B3 of the muffler cover portion 11B. At the four corners of the mounting plate portion 20C, bolt insertion holes 20C1 are provided penetrating upward and downward at positions corresponding to the respective screw holes 11B3.

  The vertical cover portion 20A has an annular space with the vertical cylinder portion 18A of the exhaust pipe 18, and the inclined cover portion 20B has an annular space with the inclined cylinder portion 18B of the exhaust pipe 18. Yes. Thereby, the cover main body 20 forms the discharge flow path 21 between the exhaust pipe 18. The exhaust passage 21 can circulate cooling air around the exhaust pipe 18.

  Further, similarly to the exhaust pipe 18, the opening of the inclined cover portion 20B is formed obliquely with respect to the axis of the inclined cover portion 20B so that the upper portion protrudes backward from the lower portion. In addition, the inclined cover portion 20B is arranged such that the position of the upper end portion 20B1 on the opening side is a predetermined dimension behind the opening position of the inclined cylinder portion 18B of the exhaust pipe 18. As a result, the inclined cover portion 20B suppresses dust from flowing into the exhaust pipe 18 and the cover body 20 (discharge passage 21).

  As shown in FIG. 5, the cover main body 20 arranges the attachment plate portion 20C on the upper surface 11B4 of the muffler cover portion 11B so that the attachment plate portion 20C covers the exhaust pipe insertion opening 11B2 and each screw hole 11B3. In this state, the cover body 20 can be mounted on the upper surface cover 11 by screwing the bolts 22 inserted into the bolt insertion holes 20C1 of the mounting plate portion 20C into the screw holes 11B3 of the muffler cover portion 11B.

  The cooling air introduction port 23 is provided in the muffler cover portion 11 </ b> B of the upper surface cover 11 constituting the exterior cover 8 and communicates with the cover main body 20 of the exhaust pipe cover 19. The cooling air introduction port 23 is formed as an annular passage between the exhaust pipe insertion opening 11B2 of the muffler cover portion 11B and the vertical cylinder portion 18A of the exhaust pipe 18. The cooling air introduction port 23 discharges cooling air for cooling equipment including the engine 13 disposed in the engine room 12 </ b> B of the machine room 12 between the exhaust pipe 18 and the cover body 20 of the exhaust pipe cover 19. 21.

  The air guide plate 24 introduces cooling air flowing through the engine chamber 12 </ b> B into the cooling air introduction port 23. That is, the air guide plate 24 is disposed in the engine chamber 12B on the lower surface 11B5 side of the muffler cover portion 11B, and takes cooling air from the engine chamber 12B as indicated by an arrow d in FIG. Can be included. Further, the air guide plate 24 has a structure integrated with the exhaust pipe 18 in the engine chamber 12B.

  Specifically, as shown in FIG. 5, the air guide plate 24 includes a bottom plate portion 24A and a peripheral wall portion 24B extending upward from the periphery of the bottom plate portion 24A. The bottom plate portion 24A includes a rectangular inclined plate portion 24A1 inclined upward from the upstream side to the downstream side of the cooling air flowing in the engine chamber 12B, and the downstream end (right end) of the inclined plate portion 24A1 from the downstream side. And a horizontal plate portion 24A2 extending horizontally. The horizontal plate portion 24A2 is largely chamfered so that the downstream end corresponds to the exhaust pipe insertion opening 11B2 of the octagonal muffler cover portion 11B. Further, the horizontal plate portion 24A2 is formed with a circular hole 24A3 into which the vertical tube portion 18A of the exhaust pipe 18 is inserted, and the circular hole 24A3 is provided with welding means with the lower portion of the vertical tube portion 18A being inserted. Used to secure.

  The peripheral wall portion 24B of the air guide plate 24 is formed as a U-shaped side wall extending upward from the periphery excluding the upstream edge of the bottom plate portion 24A. The peripheral wall portion 24B has a shape in which a downstream side wall plate 24B1 positioned on the downstream side in the flow direction of the cooling air surrounds the exhaust pipe insertion opening 11B2 of the muffler cover portion 11B. The upper end edge of the peripheral wall portion 24B is fixed to the lower surface 11B5 of the muffler cover portion 11B using welding means. Thus, the air guide plate 24 forms a passage for guiding the cooling air between the muffler cover portion 11B.

  The air guide plate 24 can introduce the cooling air flowing through the engine chamber 12 </ b> B into the discharge passage 21 through the cooling air inlet 23. As a result, the exhaust pipe 18 is cooled by the cooling air guided by the air guide plate 24 in the engine chamber 12B. At this time, the air guide plate 24 can be opened largely because the inclined plate portion 24A1 of the bottom plate portion 24A is inclined downward toward the upstream side, and a large amount of cooling air is discharged from the discharge passage 21. Can be efficiently guided to.

  The hydraulic oil tank 25 is provided on the revolving frame 5 so as to be located on the front side of the pump chamber 12C. The hydraulic oil tank 25 stores hydraulic oil supplied to various hydraulic actuators mounted on the hydraulic excavator 1. A fuel tank (not shown) that stores fuel to be supplied to the engine 13 is disposed on the front side of the hydraulic oil tank 25.

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

  First, the operator gets on the cab 7 and sits on the driver's seat. By operating the operating lever in this state, the lower traveling body 2 can be driven to move the hydraulic excavator 1 to the work site. Further, the operator can operate the front device 4 and the like to perform excavation work of earth and sand by operating the operation lever.

  When the excavator 1 is in operation, cooling air is supplied to the heat exchanger 16 by the cooling fan 13 </ b> A of the engine 13. Therefore, the flow of the cooling air in the machine room 12 will be described with reference to FIG.

  When the cooling fan 13A rotates, external air is sucked into the cooling air inflow chamber 12A as cooling air through the inlet 9A provided in the left surface cover 9 of the exterior cover 8 as indicated by an arrow a. The heat exchanger 16 can cool fluid such as engine cooling water and hydraulic oil through the passage of the cooling air.

  Of the cooling air that has warmed up after passing through the heat exchanger 16, a part of the cooling air is discharged to the outside from the outlet 5G1 provided in the under cover 5G of the swivel frame 5, as indicated by an arrow b. . Further, the other cooling air is discharged to the outside from an outlet 11B1 provided in the muffler cover portion 11B of the upper surface cover 11, as indicated by an arrow c. A part of the cooling air that has flowed downstream without being discharged from the outlet 11B1 is taken into the air guide plate 24 and used for cooling the exhaust pipe 18 and discharging dust, as indicated by an arrow d. Is done.

  Here, in addition to excavating and transporting earth and sand, the hydraulic excavator 1 collects and collects timber at the work site in the forest, collects and transports wood chips at the work site in the ship, Dismantling and sorting metal scrap at indoor work sites. At these work sites, dust such as fine wood chips, dust, and dust rises.

  In such a work site, the exhaust pipe cover 19 covers the exhaust pipe 18, and therefore dust can be prevented from accumulating on the upper side of the exhaust pipe 18. However, part of the dust may flow into the exhaust pipe cover 19 and accumulate on the upper side of the exhaust pipe 18.

  The temperature of the exhaust pipe 18 rises due to the heat of the exhaust gas. In particular, when the muffler 14 is provided with a particulate matter removing device composed of an oxidation catalyst and a filter for collecting and removing particulate matter (PM) contained in the exhaust gas as a processing device, the inside of the muffler 14 The temperature is known to be a high temperature of 600 ° C. or higher, for example. Therefore, when dust accumulates in the exhaust pipe 18 or dust flows into the muffler 14 through the exhaust pipe 18, the dust is affected by high heat.

  However, according to the present embodiment, the exhaust pipe cover 19 covering the exhaust pipe 18 is installed on the upper surface cover 11 of the exterior cover 8 with the lower end side covering the periphery of the exhaust pipe 18, and the upper end side from the exhaust pipe 18. Between the exhaust pipe 18 and the exhaust pipe cover 19, a cylindrical cover body 20 that exhausts the exhaust gas of the engine and the cooling air that cools equipment such as the engine 13 and the heat exchanger 16 in the machine room 12. A cooling air introduction port 23 that guides the air and a wind guide plate 24 that introduces the cooling air into the cooling air introduction port 23 are configured.

  Therefore, as shown in FIG. 2, when the engine 13 is driven and the cooling air flows in the machine room 12, the exhaust pipe cover 19 passes a part of the cooling air to the air guide plate 24 as indicated by an arrow d. Can be taken into. Thereby, the air guide plate 24 can guide the taken cooling air toward the cooling air inlet 23. In addition, in the cover main body 20, the introduced cooling air can be circulated through the discharge passage 21 formed between the exhaust pipe 18 and discharged outside.

  As a result, it is possible to prevent the dust from flowing into the discharge flow path 21 by the cooling air flowing through the discharge flow path 21 in the exhaust pipe cover 19 even at the work site where the dust flies. Even if dust accumulates on the upper side of the exhaust pipe 18 or dust adheres to the inner surface of the exhaust pipe cover 19 or the outer surface of the exhaust pipe 18, the dust is easily discharged to the outside by the flow of cooling air. can do. In addition, the exhaust pipe 18 can be forcibly cooled by the cooling air flowing around it.

  The cooling air inlet 23 is provided in the upper surface cover 11 of the exterior cover 8 and communicates with the exhaust pipe cover 19. Thereby, the cooling air guided by the air guide plate 24 can be introduced into the exhaust pipe cover 19 through the cooling air inlet 23.

  The air guide plate 24 is positioned in the lower surface 11B5 side of the muffler cover portion 11B constituting the upper surface cover 11 and is disposed in the engine room 12B of the machine room 12. On this, the air guide plate 24 can take in the cooling air of the engine compartment 12B. Thereby, the cooling air which has flowed in the engine chamber 12B from the past can be used for dust discharge, and the dust discharge structure can be simplified.

  The air guide plate 24 has a structure integrated with the exhaust pipe 18 in the engine room 12 </ b> B of the machine room 12. Thereby, the exhaust pipe 18 can be attached to the upper surface cover 11 together with the air guide plate 24. The exhaust pipe 18 attached to the top cover 11 can be cooled by cooling air guided by the air guide plate 24 in the engine chamber 12B.

  Next, FIG. 6 and FIG. 7 show a second embodiment of the present invention. A feature of the present embodiment is that a cover member for capturing dust flowing into the cover body is provided in the cover body of the exhaust pipe cover. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  In FIG. 6, the exhaust pipe cover 31 according to the second embodiment includes a cover body 20, a cooling air introduction port 23, and an air guide plate 24 in substantially the same manner as the exhaust pipe cover 19 according to the first embodiment. It is configured. However, the exhaust pipe cover 31 according to the second embodiment is different from the exhaust pipe cover 19 according to the first embodiment in that a capture member 32 described later is provided in the cover body 20.

  The capturing member 32 captures the dust 33 that has flowed into the cover body 20. The capturing member 32 is provided, for example, opposite to the front and rear positions of the inner surface of the vertical cover portion 20A of the cover body 20. In this case, various conditions including the shape, the mounting position, and the number of the capturing members 32 are appropriately set depending on the size of the engine 13, the working environment, and the like. In other words, one capture member 32 may be annularly arranged along the inner surface of the vertical cover portion 20A, or three or more capture members 32 may be provided.

  The two capture members 32 are formed as plates that are inclined upward toward the central side, which is the exhaust pipe 18 side, for example, like a fishing hook return, and are formed on the inner surface of the vertical cover portion 20A using welding means. It is fixed. Each capturing member 32 captures the dust 33 that has entered the discharge channel 21 between the inner surface of the vertical cover portion 20A. Further, as shown in FIG. 7, each capturing member 32 is provided with a plurality of vent holes 32 </ b> A penetrating in the plate thickness direction. Each of the vent holes 32A is formed as a through hole having a diameter that prevents the dust 33 collected and collected by each capturing member 32 from dropping. The cooling air flowing through the discharge passage 21 can be passed through each vent 32A.

  Each capturing member 32 configured in this manner can capture a part of the dust 33 that has entered when a part of the dust 33 scattered around when the engine 13 is stopped enters the cover body 20. . Moreover, when the engine 13 is started and the cooling air flows in the machine room 12, the capturing member 32 allows the cooling air to pass from the lower side to the upper side through the air holes 32A, thereby capturing the captured dust. 33 can be discharged outside the discharge channel 21.

  Thus, also in the second embodiment configured as described above, substantially the same operations and effects as those of the first embodiment described above can be obtained. In particular, in the second embodiment, in the cover body 20 of the exhaust pipe cover 31, two capture members 32 that capture the dust 33 that has flowed into the cover body 20 are provided. Thereby, even when the dust 33 flows into the cover main body 20, the dust 33 that has flowed in can be captured by the capturing members 32, so that the inside of the machine room 12 can be kept clean. Further, since each trapping member 32 is provided with a plurality of vent holes 32A, the trapped dust 33 can be discharged to the outside of the discharge channel 21 by circulating cooling air through the vent holes 32A. it can.

  In each embodiment, the crawler excavator 1 is described as an example of the construction machine. However, the present invention is not limited to this, and may be applied to, for example, a hydraulic excavator provided with a wheel-type lower traveling body. Furthermore, it can be widely applied to other construction machines equipped with an engine such as a hydraulic crane.

1 Excavator (construction machine)
2 Lower traveling body (car body)
3 Upper swing body (car body)
DESCRIPTION OF SYMBOLS 4 Front apparatus 5 Turning frame 6 Counterweight 8 Exterior cover 9 Left side cover 10 Right side cover 11 Upper surface cover 11B Muffler cover part 11B2 Exhaust pipe insertion opening 12 Machine room 12A Cooling air inflow chamber 12B Engine room 12C Pump room 13 Engine 14 Muffler 18 Exhaust pipe 19, 31 Exhaust pipe cover 20 Cover body 21 Discharge flow path 23 Cooling air inlet 24 Air guide plate 32 Capture member 33 Dust

Claims (4)

A front device is provided at the front, and a self-propelled vehicle body provided with a counterweight at the rear is provided.
The vehicle body has
A machine room disposed on the front side of the counterweight and covered by an exterior cover;
An engine disposed in the machine room;
An exhaust pipe for guiding the exhaust gas discharged from the engine to the upper outside of the machine room;
In a construction machine comprising an exhaust pipe cover that covers the exhaust pipe,
The exhaust pipe cover is
A cylindrical cover body that is installed in the exterior cover with a lower end side covering the periphery of the exhaust pipe, and an upper end side that discharges exhaust gas from the exhaust pipe to the outside;
A cooling air inlet for guiding cooling air for cooling the equipment in the machine room between the exhaust pipe and the exhaust pipe cover;
A construction machine comprising an air guide plate for introducing the cooling air into the cooling air introduction port.   The construction machine according to claim 1, wherein the cooling air introduction port is provided in an upper surface cover of the exterior cover and communicates with the exhaust pipe cover.   The construction machine according to claim 1, wherein the air guide plate is disposed on the lower surface side of the exterior cover and is disposed in the machine room to take in cooling air in the machine room.   The air guide plate has a structure integrated with the exhaust pipe in the machine room, and the exhaust pipe is cooled by cooling air guided by the air guide plate in the machine room. The construction machine according to claim 1.

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