Patent Application
20080169142
1. Field of the Invention
The present invention relates to a cooling structure of a construction machine having a soundproof function on an intake side which conducts cooling air introduced from the exterior into a heat exchanger.
2. Description of the Related Art
As techniques for enhancing the soundproof function on an intake side in a construction machine such as a hydraulic excavator, there are known the techniques disclosed in Patent Laid-Open No. 2006-206034 and 2006-207576 (hereinafter referred to as Patent Literatures 1 and 2, respectively).
With a hydraulic excavator as an example, the above conventional techniques will now be described.
In the rear section of the upper rotating body there is provided an engine room 2 covered with a cover member 1 such as a part of an engine guard and a counterweight and an upper surface of a fuel tank.
Within the engine room 2 there are provided an engine 3, a hydraulic pump (not shown), a cooling fan 4 adapted to be driven by the engine 3 to suck the outside air, as well as plural heat exchangers (shown here as one heat exchanger) 5 such as a radiator for cooling the engine, an oil cooler and an intercooler.
An intake chamber 6 is formed on an intake side of the heat exchanger 5 within the engine room 2 and a first intake port 7 for introduction of the outside air is formed in an upper surface of the intake chamber 6 (an upper surface of an intake-side end portion of the cover member 1).
The intake room 6 is formed independently (in an air flow-cutoff state) by the heat exchanger 5, a suitable dividing member and a sealing member with respect to the space of the engine room 2 where the engine 3, etc. are installed. Within the intake chamber 6 is installed a shielding member (a duct 8 in the technique shown in
The duct 8 is formed in a box shape using a duct material different from the material of the cover member 1 and is mounted so as to surround a heat exchanger core surface 5a in a hermetically sealed state.
On the other hand, the shielding plate 9 is formed to shield between the heat exchanger core surface 5a and the first intake port 7, which is throughout the whole width of the intake chamber.
In the case of a duct type there is provided a duct front face portion 10 opposed to the heat exchanger core surface 5a, while in the case of a shielding plate type a second intake port 11 is formed in the shielding plate 9 and a dust preventing filter 12 is provided to the second intake port 11 so as to cover the whole surface of the second intake port 11.
An absorbing member 13 is provided on each of a wall surface in the intake chamber 6, namely, on the inner surface of the cover member 1, and inner and outer surfaces of the duct 8. The cover member 1 and the duct 8 form the intake chamber 6.
These structures are double structures in which the interior of the intake chamber 6 is partitioned into two compartments by the shielding members 8, 9, as is described also in Patent Literatures 1 and 2. Therefore, by suppressing, with use of the shielding members 8, 9, the sound (direct sound) propagated directly from the heat exchanger core surface 5a to the exterior to suppress the diffusion thereof, and by the attainment of a sound damping effect based on reflection and attenuation of a sound with the shielding members 8, 9, in addition to a sound damping effect induced by the chamber wall of the intake chamber 6, it is possible to enhance the intake-side soundproof performance remarkably in comparison with the case where the shielding members 8 and 9 are not formed.
Thus, in the construction having the shielding members 8, 9 installed within the intake chamber 6, a vertically extending intake passage 14 is formed between the shielding members 8, 9 (or the duct front face portion 10 in case of the duct type) and the cover member 1.
With reference to the duct type shown in
The larger the amount of air (air volume) passing through the intake passage 14, the higher the cooling efficiency of the heat exchanger 5, etc. This air volume depends on the sectional area of the intake passage 14, but actually the sectional area of the intake passage cannot always be taken sufficiently large in a construction machine wherein a limitation is placed on the space of the intake chamber 6 because of a demand for the reduction of size like a hydraulic excavator.
In this connection, according to the above conventional techniques, the shielding members 8, 9 are used taking note of only the intake-side soundproof performance, and in case of installing the duct front face portion 10 or the shielding plate 9 vertically as in the drawing, there has been a room for improvement in point of ensuring a required air volume.
It is an object of the present invention to provide a cooling structure of a construction machine capable of attaining both intake-side soundproof performance and assurance of a desired air volume.
The cooling structure of a construction machine according to the present invention comprises an engine, a heat exchanger and a cooling fan within an engine room covered with a cover member, and is constructed in such a manner that the outside air is sucked into the engine room by rotation of the cooling fan and is passed through the heat exchanger, further it satisfies the following conditions:
Thus, according to the present invention, on the premise of the construction in which a shielding member (e.g., a duct or a shielding plate) is disposed on the front side of the heat exchanger core surface in the intake chamber, a second intake port is formed on the intake passage-forming surface of the shielding member, and at least the portion of the intake passage-forming surface where the second intake port is formed is inclined in a direction in which the sectional area of the intake passage becomes maximum on the first intake port side and decreases gradually toward the opposite side. Therefore, in the following points, it is possible to increase the air volume for cooling while making the most of the soundproof performance of the shielding member.
In connection with the air volume:
Reference is here made as an example to the construction (see
Also by moving the whole of the shielding members 8, 9 vertically to the heat exchanger side with respect to the illustrated position thereof in the techniques shown in
In this case, however, the whole of the space (the spacing between the second intake port 11 and the heat exchanger core surface 5a) formed inside the shielding members 8, 9 is narrowed, so that the air flowing into the space through the second intake port becomes difficult to pervade uniformly throughout the whole of the heat exchanger core surface. Consequently, the cooling efficiency of the heat exchanger, etc. is deteriorated and the improvement of the cooling efficiency, which is the very object of increasing the amount of air to be introduced, is not attained to a satisfactory extent.
On the other hand, according to the present invention, since the space inside the shielding member changes in a continuous manner by tilting the shielding member, the introduced air becomes easier to pervade uniformly throughout the whole of the heat exchanger core surface. That is, it is possible to increase the air volume while ensuring a uniform air supplying function for the whole of the heat exchanger core surface.
In connection with soundproof function:
Soundproof effects attained by the provision of the shielding member, such as a direct sound diffusion leakage suppressing effect based on the double structure with the interior of the intake chamber being partitioned into two compartments by the shielding member, a sound damping effect by the provision of a chamber wall of the intake chamber and a sound damping effect attained by reflection and attenuation of a sound with the shielding member, can be obtained almost equally to the case where the intake passage-forming surface is not inclined.
Moreover, as described above, since it is possible to increase the air volume and thereby enhance the cooling capacity, it becomes possible to decrease the number of revolutions (fan noise) of the cooling fan.
In this way it becomes possible to attain both the soundproof performance on the intake side and assurance of a desired air volume.
In each of the first to ninth embodiments shown in
In the first embodiment the following basis construction is the same as in the technique shown in
Using a duct material different from the material of the cover member 21, the duct 28 is formed independently in the shape of a box having an upper surface 29, a bottom 30, both front-rear side faces 31 and 32 and a front face portion 33 opposed to a heat exchanger core surface 25a.
The duct 28 is mounted in a state in which it surrounds the heat exchanger core surface 25a in an airtight manner (for example in a state in which an opening edge portion on the heat exchanger side is in hermetic sealing contact with an edge frame portion of the heat exchanger core surface 25a).
A second intake port 34 which opens horizontally is formed in the front face portion 33 of the duct 28. Further, a filler 35 for dust prevention is attached to the second intake port 34 so as to cover the same port.
In this embodiment the duct bottom 30 is declined on its front side toward the heat exchanger core surface 25a.
With the dust 28, the heat exchanger core surface 25a and the first intake port 27 are isolated from each other and the interior of the intake chamber 26 is partitioned into two compartments (an intra-duct space and the other space, hereinafter referred to as the first compartment and the second compartment, respectively) 26a and 26b.
With the duct 28, moreover, there is formed a substantially L-shaped air flow passage through which, as indicated by arrows in
A sound absorbing member 36 is attached to each of an inner surface of the cover member 21 which forms the intake chamber 26, as well as inner and outer surfaces of the duct 28.
Soundproof performance based on the above basic construction is basically the same as in the technique shown in
More specifically, the heat exchanger core surface 25a is enclosed with the independent duct 28 and a flow path connecting the core surface 25a with the exterior is bent in a substantially L shape. Consequently, a direct sound propagated directly from the core surface 25a to the exterior can be shut off by the duct 28.
On the other hand, an intake sound leaving the heat exchanger core surface 25a repeats reflection an attenuation in the first compartment 26a and the second compartment 26b in the intake chamber 26, so that it is possible to obtain a high sound damping effect.
Further, the structure in question is an all-around double duct structure forming the independent duct 28 in the intake chamber 26 which is a kind of duct. Therefore, in comparison with a single structure comprising only the intake chamber 26, a sound is doubly blocked throughout the whole circumference of the cover member 21 which forms the intake chamber 26 and the duct 28, whereby the sound leak preventing effect can be enhanced to a remarkable extent. In addition, the sound propagation route can be restricted by the double duct structure. Particularly, in the case where a sound absorbing material 36 is provided in the interior as in this embodiment, it is possible to further enhance a sound damping effect attained by the sound absorbing material 36.
Besides, since the heat exchanger core surface 25a as a sound outlet is enclosed with the duct 28, it is possible to prevent diffusion of a sound in all directions.
In view of these points, the soundproof effect on the intake side can be enhanced to a great extent in comparison with the case where the duct 28 is not provided.
In this construction, moreover, since the above effect is attained by provision of the duct 28 in the intake chamber 26, there does not occur the drawback that the space for other equipment is narrowed as in case of adopting a construction wherein the soundproof function is enhanced by expanding the intake chamber 26; besides, the construction in question can be also applied to existing machines easily.
If only air-tightness is maintained between the duct 28 and the circumference of the heat exchanger core surface of the duct 28, the direct sound from the core surface 25a can be shut out positively by the duct 28. Therefore, in comparison with the case where air-tightness is provided throughout the whole inner surface of the cover member 21 which is of a complicated shape including a three-dimensional curved surface, a much narrower sealing area suffices. Besides, high degree of sealing can be attained because it is easy to seal.
In this embodiment, an intake passage 37 is formed between the front face portion (intake passage-forming face) 33 of the duct 28 and the side face portion of the cover member 21 opposed thereto. This point is the same as in the known techniques shown in
In this embodiment, the whole of the front face 33 of the duct 28 is inclined in a direction in which the sectional area of the intake passage 37 becomes maximum on the first intake port 27 side (upper portion) as an air inlet side and decreases gradually toward the opposite side (lower portion), and the second intake port 34 is formed in a downstream-side half (lower half) of the inclined front face portion 33.
In this embodiment, as compared with the structure (the front face portion 10 is vertical) shown in
According to this construction it is possible to obtain the following effects.
In this way it is possible to increase the air volume and enhance the cooling efficiency while ensuring a certain soundproof performance on the intake side, this is, it is possible to obtain both soundproof performance and cooling efficiency.
Moreover, since the cooling capacity is enhanced by increasing the air volume as described above, it also becomes possible to decrease the number of revolutions of the cooling fan 24 and thereby further reducing the fan noise.
In this embodiment, since the whole of the second intake port 34 is positioned lower than the first intake port 27, there is no fear of a sound being directly propagated side of the machine. That is, “machine-side noise” can be greatly reduced.
According to the layout adopted in the first embodiment a part of the heat exchanger core surface 25a is seen directly from the exterior through the first and second intake ports 27, 34.
More specifically, according to the layout adopted in the first embodiment, a straight line B joining the outermost end of the first intake port 27 and an upper end of the second intake port 34 clearly lies above a straight line A joining an outer end of the first intake port and a lower end of the heat exchanger core surface 25a, although the degree thereof is slight as shown in
Consequently, there occurs leakage of a direct sound propagated directly from the heat exchanger core surface 25a to the exterior although the amount of the leakage is small.
For improvement on this point, in this second embodiment there is adopted a layout such that the second intake port 34 is positioned lower than in the first embodiment and on the side opposite to the heat exchanger 25 while the size thereof remains the same as in the first embodiment, whereby the straight line B becomes almost aligned with the straight line A (complete alignment, or the straight line B lies below or slightly above the straight line A).
In this case, the duct front face portion 33 is extended downward in its inclined state and the duct bottom 30 is made horizontal.
As a result, the direct sound can be shut out by the duct 28.
In the first and second embodiments the second intake port 34 is formed on only the intake downstream side (lower half) of the duct front face portion 33, while in this third embodiment a second intake port 34 is formed throughout the whole face of the duct front portion. In this case, the duct front portion no longer exists substantially as a face and is therefore not indicated by a reference numeral in the drawing.
This construction is disadvantageous in point of shutting off the direct sound because the area of the heat exchanger core surface 25a which is seen directly from the exterior becomes wider, but is advantageous in point of cooling efficiency because the introduced air can be supplied to the heat exchanger core surface 25a at a minimum resistance.
In this fourth embodiment a second intake port 34 is formed in the whole face of the duct front face portion as in the third embodiment, but only the intake upstream side (upper half) is inclined.
This embodiment is the same as the first to third embodiments in the construction that the duct front face portion is inclined at least at the portion where the second intake port 34 is formed and also in the effect that the sectional area of the intake passage can be increased in the second intake port portion than in the publicly known art.
The filter 35 may be wholly constituted by a single filter comprising an inclined portion and a vertical portion or may be constituted by two filters which are an inclined portion and a vertical portion as illustrated in the drawing.
This construction is advantageous in that when devices such as an air cleaner are to be installed in the first compartment 26a of the intake chamber, it is easy to ensure a space for the installation at the bottom (inside the uninclined portion).
A description will be given below about the results of numerical analysis made for verification of the air volume increasing effect according to the present invention.
With respect to the structure of the first embodiment shown in
As a result, in the structure shown in
With respect to the structure of the third embodiment shown in
As a result, in the uninclined structure the passing air volume was 84.0 m3/min, while in the structure of the third embodiment it was 88.7 m3/min, indicating an air volume increase of 7%.
The analysis was made also as to the structure of the fourth embodiment shown in
In each of the first to fourth embodiments the duct front face portion 33 is formed as an intake passage-forming face and the second intake port 34 is formed therein, while in this fifth embodiment both front-rear side faces 31 and 32 of the duct 28 serve as intake passage-forming faces, the whole of both side faces 31 and 32 is inclined in a direction in which the sectional area of a pair of intakes passages 37 becomes maximum on a first intake port 27 side (upper portion) and decreases gradually toward the opposite side (lower portion), and second intake ports 34 are formed in the thus-inclined both side faces 31 and 32.
According to this construction, a total opening area of the second intake ports 34 can be taken large. Therefore, the increased air volume can be supplied to the heat exchanger core surface 25a efficiently at low resistance.
Although in this embodiment the second intake ports 34 are formed approximately throughout the whole except upper and lower portions of both side faces 31 and 32, the second intake ports 34 may be formed throughout the whole of both side faces or may be formed in only the lower half portions of both side faces 31 and 32 as in the second embodiment, or they may be formed throughout the whole of both side faces and only the upper half portions of both side faces may be inclined as in the fourth embodiment.
If the whole of the duct front face portion 33 is inclined and the second intake port 34 is formed throughout the duct front face portion as in the third embodiment shown in
In view of this point, according to a sixth embodiment of the present invention, with the construction of the third embodiment as a premise, the upper surface portion of the cover member 21 is raised and the first intake port 27 is formed at a position higher than in the third embodiment and shift to the heat exchanger 25 side (to the right side in the drawing).
In this case, in order to ensure an opening area necessary for the intake port 27, it is preferable that the heat exchanger-side opening edge portion of the first intake port 27 in the cover member 21 be inclined as shown in the drawing.
By so doing, as shown in the drawing, it is possible to make straight lines A and B approximately coincident with each other and hence possible to obtain a state in which the heat exchanger core surface 25a is not directly seen from the exterior.
In a seventh embodiment of the present invention, as a modification of both first and second embodiments, the whole of the duct front face portion 33 is inclined and a second intake port 34 is formed in only the upper half of the duct front face portion.
According to this construction, in comparison with the first and second embodiments, there is a disadvantage that the heat exchanger core surface 25a is easily seen directly from the exterior, but there is attained a high air volume increasing effect because the second intake port 34 lies in the portion of a maximum sectional area and hence the introduced air can be supplied into the duct 28 smoothly without waste.
In an eighth embodiment of the present invention, a guide plate 38 is disposed in an inlet portion of the second intake port 34 in the lower portion of the second compartment 26b of the intake chamber.
As shown in
According to this construction, the air sucked in from above is turned its flowing direction smoothly by the guide plate 38 at the inlet portion of the second intake port 34 and can be conducted positively to the second intake port 34.
Besides, since the guide plate 38 is inclined, it is possible to prevent staying of air and the creation of a turbulent flow at the inlet portion of the second intake port 34.
Although the construction of the first embodiment is premised here, the above construction using the guide plate 38 is also applicable to the other embodiments.
According to a ninth embodiment of the present invention, in a so-called rear small rotating type (including a rear ultra-small rotating type) machine in which a counterweight is used also as a cover member in the rear of the engine room and both right and left side portions thereof (only the left side portion is shown) 39 are positioned in a lapping state sideways of the engine room 22, an air guide surface 40 for conducing the introduced air to the second intake port 34 is formed in a forwardly descending stepwise shape in a lower part of an inner surface of the left side portion 39 which faces the intake chamber 26 in the counterweight.
According to this construction, the flow of air in the inlet portion of the second intake port 34 can be improved by the air guide surface 40. That is, a good intake performance can be attained even without addition of another guide plate. Therefore, the cost can be kept low.
Although in this embodiment the air guide surface 40 is formed stepwise due to a restriction on molding of the counterweight, if there is no such restriction, it is preferable that the air guide surface 40 be formed as such a forwardly declining rectilinear slant surface as indicated by a dash-double dot line in
In a tenth embodiment of the present invention, a square shielding plate 41 is used as the shielding member in place of the duct 28 described in each of the first to ninth embodiments.
The shielding plate 41 is disposed in a state in which its peripheral edge portion contacts the inner surface of the cover member 21 present on four sides and the shielding plate partitions the interior of the intake chamber 26 into a first compartment 26a on the heat exchanger 25 side and a second compartment 26b on the opposite side throughout the entire width in the forward-rear direction of the machine.
In this construction, the whole of the shielding plate 41 serves as an intake passage-forming surface which forms an intake passage 37 between it and a side face portion of the cover member, and the whole of the shielding plate 41 is inclined in a direction in which the sectional area of the intake passage 37 becomes maximum at the upper portion and decreases gradually toward the lower portion.
A second intake port 34 with filter 35 is formed in the shielding plate 41 and an L-shaped air flow passage is formed by the shielding plate 41. This construction is the same as in the other embodiments.
The second intake port 34 may be formed in only the lower half portion as shown in the drawing or may be formed throughout the whole of the shielding plate. Moreover, without tilting the whole of the shielding plate 41, only the upper half portion may be inclined as in the fourth embodiment using the duct type.
Also according to the shielding plate type construction of this tenth embodiment, the intake chamber 26 is formed as a double wall structure in the horizontal direction by disposing the shielding plate 41 within the intake chamber 26. Consequently, a sound can be blocked doubly by the cover member 21 and the shielding plate 41. A high sound damping effect can be obtained because a sound repeats reflection and attenuation in the first and second compartments 26a, 26b of the intake chamber 26. Moreover, there is obtained a sound damping effect by the L-shaped flow passage. As a result, it is possible to obtain a soundproof effect almost equal to that in the duct type of each of the first to ninth embodiments.
Further, the effect of increase in air volume induced by inclination of the shielding plate 41 can also be obtained as in the duct type.
That is, also in the shielding plate type it is possible to obtain both soundproof function and cooling efficiency.
Although the invention has been described with reference to the preferred embodiments in the attached figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-006972 | Jan 2007 | JP | national |
