Cooling Fan Mounting Structure for Construction Machine

Abstract

A structure for mounting a cooling fan (30) includes a spider (31) and blades (32) at free ends of mounting arms (31c) of the spider (31). A rotation center portion (31b) of the spider (31) is mounted on a rotating shaft (33) through a fan adaptor (60), the rotating shaft (33) being driven by an engine (27). A partition member (70) for closing gaps in the spider (31) is mounted on the fan adaptor (60). As a result of this configuration, the gaps between the mounting arms (31c) of the spider (31) can be reliably closed, and therefore the backflow of air from the downstream side (high pressure side) of the cooling fan (30) to the upstream side (low pressure side) thereof can be prevented.

Description

TECHNICAL FIELD

The present invention relates to a structure for mounting a cooling fan adapted to air-cool a heat exchanger, such as a radiator and an oil cooler, in a construction machine.

BACKGROUND ART

in general, a construction machine such as a hydraulic shovel (excavator) uses a diesel engine (internal combustion engine) to drive a hydraulic pump. A pressurized working oil is sent to a hydraulic actuator, such as a hydraulic cylinder and a hydraulic motor, from the hydraulic pump such that the construction machine performs certain operations and movements. Because of such configuration, a heat exchanger such as a radiator and an oil cooler is provided in the vicinity of the engine, together with a cooling fan. High-temperature engine cooling water and high-temperature working oil flow through the heat exchanger. As the cooling fan is driven (rotated) by a driving force of the engine to send air, the engine cooling water and the working oil flowing through the heat exchanger is forcibly cooled by the air (by ventilation).

Recent construction machines are often equipped with an intercooler to reduce the concentration of nitrogen oxide or the like in an exhaust gas under exhaust gas regulations in recent years. The intake air of the engine is supercharged by a turbocharger, and adiabatically compressed. Then, she intercooler cools the intake air to a predetermined temperature in order to increase a charging efficiency and lower the combustion temperature. Thus, the intercooler suppresses the generation of nitrogen oxides (NOx) in the exhaust gas. Some construction machines are equipped with a cooled exhaust gas recirculation system (cooled EGR system) to reduce the oxygen concentration in a combustion air and in turn reduce the generation of nitrogen oxides (NOx) in the exhaust gas.

When the intercooler and/or the cooled exhaust gas recirculation system is used, a load of the heat exchanger increases. Thus, a conventional cooling fan is difficult to ensure a sufficient amount of cooling air at low noises. In order to ensure a sufficient amount of cooling water at low noises, the cooling fan has to have a larger diameter. However, this increases the weight of blades of the cooling fan, and in turn increases the centrifugal force. This creates a problem in terms of strength.

To deal with the above-described facts, a metallic spider having a high strength, which is disclosed in for example in Patent Literature 1 (will be mentioned), is combined with light-weight resin blades, which generates less noises, to provide a cooling fan, which is referred to as a hybrid fan. If the conventional, cooling fan is replaced with the hybrid fan, it is possible to ensure a sufficient amount of cooling air at reduced noises.

LISTING OF REFERENCES

Patent Literatures

PATENT LITERATURE 1: Japanese Patent No. 4565006

PATENT LITERATURE 2: Japanese Patent Application Laid-Open (Kokai) Publication No. 11-94419

PATENT LITERATURE 3: Japanese Patent Application Laid-Open (Kokai) Publication No. 2001-329839

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

The spider of the cooling fan that has a configuration disclosed in Patent Literature 1 (Japanese Patent No. 4565006) has a size as small as possible to reduce the weight and to facilitate the machining. Thus, there are gaps between mounting arms of the spider. When the cooling fan is driven (rotated), part of the air on the downstream side (high pressure side) of the fan flows back to the upstream side (low pressure side) through the gaps. This may result in a large loss in the amount of air sent by the cooling fan.

To prevent, this backflow, a disc-shaped partition member may be provided on the downstream side of the cooling fan, as disclosed in Patent Literatures 1 and 2 (Japanese Patent. No. 4565006, and Japanese Patent Application Laid-Open Publication No. 11-94419). However, a certain gap must be left between the cooling fan and the rotating shaft to avoid interference between the cooling fan and the rotating shaft when the cooling fan rotates. Therefore, there is still a possibility that part of the air may flow backward from the upstream side (high pressure side) of the fan through the gap.

The present invention is proposed to address these problems, and an object of the present invention is to provide a novel cooling fan mounting structure of a construction machine, that can prevent the backflow of the air to the upstream side (low pressure side) of the cooling fan from the downstream side (high pressure side).

Solution to Overcome the Problems

In order to overcome the above-described problems, a first aspect of the present invention provides a structure for mounting a cooling fan in a construction machine. The cooling fan includes a spider, and blades mounted on free ends of mounting arms of the spider. A rotation center portion of the spider is mounted on a rotating shaft via a fan adaptor. The rotating shaft is driven by an engine. A partition member for closing (blocking) gaps between the mounting arms of the spider is mounted on the fan adaptor.

According to the above-described configuration, the gaps between the mounting arms of the spider are reliably closed. In addition, the partition member rotates together with the cooling fan, and therefore no gap is left between the rotating shaft and the partition member. As a result, it is possible to reliably prevent the backflow of air from the downstream side (high pressure side) of the cooling fan to the upstream side (low pressure side).

According to a second aspect of the present invention, the partition member of the cooling fan mounting structure of the first aspect includes a cylindrical main body of the partition member that can removably engage over the an adaptor, and a handguard-like partition plate around the partition member main body. With this configuration, the partition member main body is easily mounted on the fan adapter. Also, she handguard-like partition place can reliably close the gaps of the spider.

According to a third aspect of the present invention, the partition member of the cooling fan mounting structure of the first aspect includes a circular plate interposed between the fan adapter and the rotation center portion of the cooling fan. With this configuration, the mounting of the partition member becomes easier, and the gaps in the spider are reliably closed (blocked).

According to a fourth aspect of the present invention, the partition member of the cooling fan mounting structure of the first aspect is made from resin. When the partition member is made from resin, the partition member is given a strength that is sufficient to prevent the backflow of the air to the downstream side of the fan from the upstream side. Also, the overall weight of the cooling fan mounting structure can be reduced.

Advantages of the Invention

The present invention can reliably close (block) the gaps between the mounting arms of the spider. In addition, the present invention creates no gap between the rotating shaft and the partition member because the partition member rotates together with the cooling fan. Consequently, it is possible to reliably prevent the backflow of the air to the upstream side (low pressure side) of the fan from the downstream side (high pressure side).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general view of a hydraulic shovel 100, which is one example of a construction machine, according to one embodiment of the present invention.

FIG. 2 is a plan view showing an exemplary structure inside an engine room 22.

FIG. 3 is a plan view of an exemplary cooling fan 30 according to one embodiment of the present invention.

FIG. 4 is a view useful to describe the flow of the air generated by the cooling fan 30 that employs the mounting structure according to the embodiment of the present invention.

FIG. 5 is an exploded perspective view of the structure for mounting the cooling fan 30 according to the embodiment of the present invention.

FIG. 6 is a plan view of a cooling fan 30 that has a fan adapter 60 and a partition member 70 attached thereto according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view of a structure for mounting the cooling fan 30 according to another embodiment of the present invention.

FIG. 8 is a side view of an example of a conventional structure for mounting a cooling fan 30.

MODE FOR CARRYING OUT THE INVENTION

Now, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an overall view of a hydraulic shovel (power shovel, excavator) 100, which is an example of a construction machine, according to one embodiment of the present invention. As illustrated in the drawing, the hydraulic shovel 100 includes, as its main components, a lower traveling body 10, and an upper swing body 20 swingably disposed on the lower traveling body 10. The lower traveling body 10 has a pair of crawlers 11, supported from a traveling body frame (not shown). The crawlers 11 are parallel to each other. Each of the crawlers 11 is equipped with a motor 12 that drives a crawler belt (caterpillar band) thereof. The motor 12 is hydraulically operated and used for the traveling of the hydraulic shovel. The hydraulic shovel can move as the crawler belts are driven by the associated motors 12.

The upper swing body 20 has, as its main components, an engine room 22 to house an engine disposed on the swing body frame 21 as well as various equipment such as a heat exchanger and a battery. The upper swing body 20 also has, as its main components, a driver's cabin 23 provided in the left front of the engine room 22, a front working unit 24 extending forward from the right portion of the drive's cabin 23, and a counter weight 25 disposed behind the engine room 22 to counterbalance the weight of the front working unit 24.

The front working unit 24 has, as its main components, a boom 24a extending forward from the swing body frame 21, an arm 24b swingably attached to a front end of the boom 24a, and a bucket 24c swingably attached to a front end (free end) of the arm. 24b. The boom 24a, the arm 24b and the bucket 24c are operated (driven) by a boom cylinder 24d, an arm cylinder 24e, and a bucket cylinder 24, respectively. The cylinders 24d, 24e and 24f are hydraulically extended and retracted.

As shown in FIG. 8, the engine room 22 is covered with an engine room cover 26 that has a plurality of air inlet openings 26a. A diesel engine 27 is housed in the engine room 22. Also, a heat exchanging unit 28 is placed in the vicinity of the diesel engine 27. The diesel engine 27 and the heat exchanging unit 28 are fixedly secured on the swing body frame 21 with tightening bolts (not shown) and engine mounting parts (not shown).

As shown in FIG. 2, the heat exchanging unit 28 has an oil cooler 28a through which a working fluid flows, a radiator 28b through which engine cooling water flows, and an intercooler 28c to cool the intake air to be introduced to the engine. The oil cooler 28a, the radiator 28b and the intercooler 28c are arranged next to each other in a line. Between the heat exchanging unit 28 and the diesel engine 27, there is provided the cooling fan 30. The cooling fan 30 is surrounded by a shroud 40 and covered with the shroud 40.

As illustrated in FIG. 2, a hydraulic pump 50 is provided on the flywheel (not shown) side of the diesel engine 27. The working oil in a working oil tank (not shown) is pressurized and sent to various actuators through respective valves by the hydraulic pump 50 as the diesel engine 27 applies a driving force to the hydraulic pump 50.

As shown in FIG. 3, the cooling fan 30 has a spider 31 made from a metal such as aluminum, and a plurality of (six in this embodiment) blades 32, 32, 32, 32, 32 and 32 attached to the spider 31. The spider 31 has a rotation center portion 31b, which has a through hole 31a, and a plurality of (six in this embodiment) mounting arms 31c, 31c, 31c, 31c, 31c and 31c around the rotation center portion 31b. The mounting arms extend radiantly, and are spaced from each other at equal intervals in the circumferential direction of the rotation center portion 31b. The resin blade 32 is fixedly attached to the free end of each mounting arm. 31c by rivets (not shown). A plurality of (four in this embodiment) bolt holes 31d are formed around the through hole 31a for the mounting of the an adapter 60.

As shown in FIGS. 4 and 5, the cooling fan 30 is mounted on the rotating shaft 33 of the diesel engine 27 via the fan adapter 60. The rotating shaft 33 is coupled to the engine 27 via a fan pulley 34, a fan belt 35, and a crank pulley 36. The driving force of the engine 27 is transmitted to the fan adapter 60 via the fan pulley 34, the fan belt 35, and the crank pulley 36. Thus, as shown in FIG. 5, the rotating shaft 33 has a flange 33b at a free end of a shaft portion 33a. A plurality of bolts 37 extending from the fan adapter 60 are screwed in a plurality of bolt holes (tapped holes) 33c formed in the flange 33b such that the rotating shaft 33 is firmly coupled to the fan adapter 60.

As shown in FIG. 5, the fan adapter 60 has a first cylindrical portion 61 and a second cylindrical portion 62. The cross-sectional shape of the first cylindrical portion 61 is rectangular, and the cross-sectional shape of the second cylindrical portion 62 is circular. The first cylindrical portion 61 has a plurality of through holes 61a. The bolts 37 extend through the through holes 61a, and screwed in the bolt holes 33c formed in the flange 33b of the rotating shaft 33 such that the rotating shaft 33 operatively connected to the engine 27 is firmly coupled to the fan adapter 60. On the other hand, the second cylindrical portion 62 has a plurality of bolt holes 62a in projecting portions at the periphery thereof. Bolts 63 extending through bolt holes 31d are screwed in the bolt holes 62a such that the cooling fan 30 is firmly coupled to the fan adapter 60.

A partition member 70, which is made from a synthetic resin, is attached to the fan adapter 60. The partition member 70 includes a partition member main body 71 and a partition plate 72. The partition member main body 71 has a cylindrical shape, and is removably fitted over the first cylindrical portion 61 of the fan adapter 60. The partition plate 72 has a handguard shape, and extends from the outer periphery of the partition member main body 71.

The partition member main body 71 is analogous to the first cylindrical portion 61, and has a cylindrical body of which cross-section is rectangular. After the partition member main body 71 fits (engages) over the first cylindrical portion 61, bolts 73 are inserted into through holes 72a and 72a formed in the lateral wall of the partition member main body 71, and screwed in bolt holes 61b and 61b formed in the upper and lower lateral wall of the first cylindrical portion 61. Thus, the partition member main body 71 is firmly assembled to the fan adapter 60. The lower bolt hole 61b is not shown in the drawing. The partition plate 72 extends radially, like a handguard, from that edge of the partition member main body 71 which is on the cooling fan 30 side. As shown in FIG. 6, the radius of the partition plate 72 reaches (or almost reaches) the inner edges (innermost parts) of the blades 32 of the cooling fan 32.

Now, the functioning of the cooling fan 30 that has the above-described mounting structure will, be described. As shown in FIG. 4, the rotating drive force of the diesel engine 27 is transmitted to the rotating shaft 33 via the crank pulley 36, the an belt 35 and the fan pulley 34 upon starting up of the diesel engine 27 such that the cooling fan 30 is caused to rotate via the fan adapter 60.

Then, as shown in FIG. 8, the ambient air is introduced into the engine room 22 from the air inlet openings 26a of the engine room cover 26. This air flows through the heat exchanger unit 28 and cools (air-cools) various coolants flowing in heat exchange tubes. Then, this air flows through the shroud 40 toward the diesel engine 27. During this flow of the air, the upstream side of the cooling fan 30 (i.e., the interior of the shroud 40), becomes a low pressure (negative pressure). Therefore, if the cooling fan 30 does not have the above-described partition member 70, part of the air on the downstream side of the cooling fan 30 (high pressure side; positive pressure side) flows back toward the shroud 40 through the gaps (“A” part in FIG. 8 and “A” part in FIG. 3) left between the root portions of the mounting arms 31c of the spider 31 and the blades 32, as shown in FIG. 8. This results in a loss.

In the embodiment of the present invention, on the other hand, the partition member 70 is attached to the fan adapter 60 as described above. Therefore, the gaps (“A” part in the drawing) left between the root portions of the mounting arms 31c of the spider 31 and the blades 32 are reliably blocked, as shown in FIG. 6. Consequently, the backflow of the air from the downstream side of the cooling fan 30 (high pressure side) toward the shroud 40 (low pressure side) does not occur, as shown in FIG. 4. This reduces the loss, as compared to the conventional structure, and increases an amount of air flow (amount of air so be sucked by the cooling fan).

Because the partition member 70 rotates together with the fan adapter 60, it is possible to attach the partition member 70 in close contact to the fan adapter 60. As a result, it is feasible to eliminate the an between the partition member 70 and the fan adapter 60, and minimize the loss in the amount of air flow. In addition, because the partition member 70 is made from a heat-resistant synthetic resin, such as phenol resin and melamine resin, or a thermosetting resin such as polyester resin, the weight of the partition member 70 is lighter than a metal. Accordingly, a load applied on the rotating shaft 33 and other components does not increase greatly, and a load on a drive source such as the engine 27 is almost the same as the conventional structure. Because use of the partition member 70 does not require modifications to the conventional fan mounting structure, the cost is suppressed. Also, it is possible to easily attach the partition member 70 on an existing structure.

Although the partition member 70 includes the cylindrical partition member main body 71 and the handguard-like partition plate 72 in order to allow the partition member 70 to be attached to the fan adapter 60 in the above-described embodiment, the partition member 70 may be a circular disc having a doughnut shape as shown in FIG. 7. When the partition member 70 is configured as shown in FIG. 7, the doughnut-shaped circular disk 70 is interposed between the fan adapter 60 and the rotation center portion 31b of the cooling fan 30 as depicted in the drawing. A plurality of bolts 64 are screwed in a plurality of tapped holes 70a formed in an inwardly extending portion of the partition member 70 from the through holes 31e of the cooling fan 30 to mount the partition member 70 such that the partition member 70 is coaxial to the rotation center portion 31b of the cooling fan 30.

REFERENCE NUMERALS AND SYMBOLS

• 100 Construction machine
• 27 Diesel engine
• 28 Heat exchanger unit
• 30 Cooling fan
• 31 Spider
• 31 b Rotation center portion
• 31 c Mounting arm
• 32 Blade
• 33 Rotating shaft
• 60 Fan adapter
• 70 Partition member
• 71 Partition member main body
• 72 Partition plate

Claims

1. A structure for mounting a cooling fan of a construction machine, the cooling fan including a spider and a plurality of blades at free ends of mounting arms of the spider respectively, with a rotation center portion of the spider being attached, via a fan adapter, to a rotating shaft driven by an engine, and a partition member being attached to the fan adapter such that the partition member closes gaps between the mounting arms of the spider.

2. The structure for mounting a cooling fan of a construction machine according to claim 1, wherein the partition member includes a cylindrical main body that removably engages over the fan adaptor, and a handguard-like partition plate around the main body of the partition member.

3. The structure for mounting a cooling fan of a construction machine according to claim 1, wherein the partition member includes a circular plate interposed and mounted between the fan adapter and the rotation center portion of the cooling fan.

4. The structure for mounting a cooling fan of a construction machine according to claim 1, wherein the partition member is made from resin.