JP2011214450A - Cooling fan device and working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure high cooling efficiency while reducing the noise.SOLUTION: The cooling fan device includes: a fan 11 disposed to be opposed to a heat exchanger 12, sucking air from the downwind side of the heat exchanger 12 by rotation, and generating cooling air passing through the heat exchanger 12; and a shielding member 10 disposed on the side opposite from the heat exchanger 12 while having the fan 11 therebetween, and arranged to obstruct rolling in winds from the downwind side of the fan 11 to the fan 11. The shielding member 10 includes a shielding wall 30 arranged to be orthogonal to a flow direction of the cooling air by rotation of the fan, a peripheral wall 31 rising from an outer peripheral part of the shielding wall 30 to the fan side, and a bored plate 33 arranged in an inside of the peripheral wall 31 and forming an air layer 32 between the shielding wall 30 and it. A plurality of through holes 33a are formed in the bored plate 33, and a thickness of the bored plate 33, a size and an opening rate of the through hole 33a, and a thickness in the air layer 32 on the shielding wall 30 side of the bored plate 33 are set so as to absorb one kind of dominant sounds peculiar to the fan 11.

Description

  The present invention relates to a cooling fan device for cooling a heat exchanger attached to a driving source such as an engine or a motor, and a work machine (for example, a construction machine or a special vehicle) provided with the cooling fan device.

  The cooling fan device described above includes a fan that causes cooling air to flow to a heat exchanger that circulates a coolant such as cooling water with a drive source.

  By the way, in recent years, needs for energy saving and noise reduction have been increased, and the cooling fan device is also required to have high cooling efficiency and low noise.

  As one configuration that can increase the cooling efficiency, a configuration shown in FIG. 9 has been proposed (see, for example, Patent Document 1). In this configuration, a heat exchanger 105 is disposed on the leeward side of the fan 100, and a plate-shaped shielding wall 101 is disposed on the leeward side of the fan 100. The shielding wall 101 rotates the fan 100 in this example. It is attached to the outer periphery of the motor 102. This shielding wall 101 can prevent wind that flows backward from the downstream side of the fan 100 toward the fan center side to smooth the air flow around the fan 100. As a result, the amount of cooling air flowing through the heat exchanger can be increased without changing the rotation of the fan, that is, the cooling efficiency can be increased.

Japanese Utility Model Publication No. 63-4400

  However, in the case of the technique disclosed in Patent Document 1, the cooling efficiency can be increased by increasing the amount of cooling air flowing through the heat exchanger as described above. On the other hand, as shown in FIG. Therefore, it is difficult to reduce the noises X1 and X2 that increase the noise level (vertical axis) at the specific frequency (horizontal axis) determined by the above.

  The present invention has been made in order to solve the problems of the prior art, and an object of the present invention is to provide a cooling fan device and a work machine capable of ensuring high cooling efficiency while reducing noise. To do.

  By the way, it is conceivable to secure a high cooling efficiency while reducing noise by giving the above-described shielding wall a sound absorbing function. As one of the structures, a structure in which a porous sound absorbing material is attached to the shielding wall is assumed. However, in the case of the structure, the sound absorption characteristic of the porous sound absorbing material is generally a characteristic in which the sound absorption rate (%) increases as the frequency increases as shown in FIG. It is not possible to efficiently absorb the prevailing sound that is very high.

  Therefore, as a result of various studies, the present invention has a sound absorbing structure in which a shielding wall is disposed on the leeward side of the fan, thereby improving cooling efficiency and further including a perforated plate having a specific shape in the shielding wall. It was found that noise reduction can be achieved without adding complexity to the surroundings of the fan. This will be described in more detail below.

  That is, there are two types of fan noise, one is turbulent sound generated by fluid flow, and the other is dominant sound generated due to the rotation of the fan described above. The former turbulent sound can be reduced by arranging a shielding wall on the leeward side of the fan to smooth the air flow around the fan. When the resonance phenomenon occurs inside the box-shaped part surrounding the fan, it becomes a problem as a booming sound. Conventionally, the above-mentioned prevailing sound could not be effectively reduced. However, in order to ensure the air volume as described above, a perforated plate and an air layer are formed on the fan side portion of the shielding wall provided on the leeward side of the fan. By providing the sound absorbing means consisting of the above, it becomes possible to absorb and reduce the dominant sound. In other words, by installing a shielding member having such a sound absorbing structure, it is possible to increase the cooling efficiency without complicating the periphery of the fan by smoothing the flow around the fan as described above, and in addition to reducing the noise. Can be achieved.

  A cooling fan device according to claim 1 of the present invention based on such knowledge is a cooling fan device that cools a heat exchanger, is provided to face the heat exchanger, and rotates to exchange the heat. A fan that generates cooling air that passes through the heat exchanger by sucking air from the leeward side of the heat exchanger, and provided on the opposite side of the heat exchanger across the fan, from the leeward side of the fan to the fan A shielding member that is disposed so as to prevent the entrainment air from flowing, and the shielding member is disposed so as to be substantially orthogonal to the flow direction of the cooling air by the rotation of the fan, and the shielding. A peripheral wall that rises from the outer peripheral portion of the wall to the fan side, and a perforated plate that is disposed inside the peripheral wall and forms an air layer between the shielding wall, and the perforated plate includes a plurality of through holes Formed, and The plate thickness of the perforated plate, the size and opening ratio of the through-hole, and the thickness of the air layer on the shielding wall side of the perforated plate provide one type of prominent sound unique to the fan. It is set to absorb sound.

  A cooling fan device according to claim 2 of the present invention is a cooling fan device that cools a heat exchanger, is provided so as to face the heat exchanger, and rotates downstream of the heat exchanger. A fan that generates cooling air that passes through the heat exchanger by sucking air from the side, and a winding that is provided on the opposite side of the heat exchanger across the fan, and is wound from the leeward side of the fan toward the fan A shielding member disposed so as to block the wind, and the shielding member is disposed so as to be substantially orthogonal to a flow direction of the cooling air generated by the rotation of the fan, and an outer periphery of the shielding wall. A peripheral wall that rises from the section toward the fan, and N (N is an arbitrary integer greater than or equal to 2) perforated plates that are spaced apart from each other in the rising direction of the peripheral wall inside the peripheral wall. Hole The perforated plate closest to the shielding wall among the plates forms a first air layer with the shielding wall, and is nth (n is an arbitrary integer from 2 to N) counted from the shielding wall. The perforated plate forms an nth air layer with the (n-1) th perforated plate counted from the shielding wall, and among these N air layers and N shielding walls, N sets of air layers and perforated plates, each having a single perforated plate and a perforated plate closest to the air layer and far from the shielding wall, each absorbs a dominant sound having a different frequency. Further, the thickness of the perforated plate in each set, the size and opening ratio of the through holes, and the thickness of the air layer are set.

  Furthermore, the cooling fan device according to claim 3 of the present invention is the cooling fan device according to claim 1, wherein the shielding member further causes the air layer to be orthogonal to the arrangement direction of the shielding wall and the perforated plate. It includes a partition member that partitions in a direction to perform.

  Furthermore, the cooling fan device according to claim 4 of the present invention is the cooling fan device according to claim 2, wherein the shielding member further includes at least one air layer in an arrangement direction of the shielding wall and the perforated plate. It includes a partition member that partitions in a direction orthogonal to the direction.

  Furthermore, a work machine according to claim 5 of the present invention is equipped with a heat exchanger and the cooling fan device according to any one of claims 1 to 4 for cooling the heat exchanger. The outer periphery of the shielding member in the cooling fan device avoids interference between an arcuate portion having an arc shape centered on the rotation center of the fan and a member disposed in the vicinity of the shielding member. And a concave portion recessed inward in the radial direction from the arc-shaped portion.

  According to the first aspect of the present invention, the shielding wall is disposed on the leeward side of the fan that generates the cooling air passing through the heat exchanger, and the shielding wall faces the fan from the leeward side of the fan. Therefore, it is possible to increase the air volume, thereby increasing the cooling efficiency. Further, the air flow around the fan is made smooth by preventing the entrainment wind, thereby reducing turbulent noise. Furthermore, since the perforated plate and the air layer are incorporated in the shielding member, the structure around the fan is not complicated. Furthermore, the perforated plate and the air layer provided inside the peripheral wall of the shielding member are the thickness of the perforated plate, the size and the opening ratio of the through hole, and the air layer on the shielding wall side of the perforated plate. By adjusting the sound absorption characteristics according to the thickness, it is possible to sufficiently absorb the dominant sound caused by the fan rotation. And the noise reduction is achieved by the reduction of the dominant sound and the above-described reduction of the turbulent sound.

  Here, the parameters contributing to the sound absorption of the dominant sound correspond to the plate thickness of the perforated plate, the size and opening ratio of the through hole, and the thickness of the air layer on the shielding wall side of the perforated plate. By designing according to the frequency of the dominant sound for which the values of these parameters are to be reduced, the dominant sound having that frequency can be sufficiently absorbed as described above.

  The cooling fan device according to claim 2 of the present invention has the following effects in addition to the same effects as the cooling fan device of claim 1. That is, the perforated plate and the air layer are provided on the shielding member in a number corresponding to the dominant sounds to be absorbed that are a plurality of different frequencies, and the corresponding number of perforated plates and air layers in the corresponding number Since four parameters are set in relation to the frequency of the prevailing sound to be absorbed, all the prevailing sound to be absorbed (upper limit of the number of perforated plates and air layers provided in the shielding member) is shielded by one. It can be absorbed by the member. At this time, the prevailing sounds reduced by the N sets of perforated plates and the air layer incorporated in the shielding member are different in frequency in each set, and are the same as the total number of prevailing sounds generated by the rotation of the fan. Or a small number.

  In the cooling fan device according to claims 3 and 4 of the present invention, the air layer is partitioned by the partition member in a direction orthogonal to the direction in which the shielding wall and the perforated plate are arranged. In the layer, the spherical wave can be brought close to the plane wave, and the sound absorbing performance can be sufficiently exhibited.

  Furthermore, in the work machine of the present invention, even if a member that interferes with the shielding member is disposed near the position where the shielding member constituting the cooling fan device of the present invention is disposed, the outer periphery of the shielding member is the fan. Since there is an arc-shaped part centered on the rotation center of the lens and a concave part recessed inward in the radial direction, interference is avoided by arranging the concave part corresponding to the interfering member. It becomes possible to install the cooling fan device without changing the configuration of the work machine.

It is a mimetic diagram showing the engine neighborhood of a hydraulic excavator as a work machine incorporating a cooling fan device concerning a 1st embodiment of the present invention. (A) is a side view which shows a shielding member, (b) is a front view which shows a shielding member. It is a figure which shows the sound absorption characteristic (it shows with a continuous line) of the shielding member in 1st Embodiment of this invention, and has taken the frequency and the vertical axis | shaft the sound absorption rate (%). (A) is a side view which shows the shielding member in the cooling fan apparatus which concerns on 2nd Embodiment of this invention, (b) is a front view which shows a shielding member. It is a figure which shows the sound absorption characteristic (it shows with a continuous line) of the shielding member in 2nd Embodiment of this invention, The frequency is taken on a horizontal axis and the sound absorption rate (%) is taken on the vertical axis | shaft. It is explanatory drawing of the shape of the other shielding member applied to this invention. It is explanatory drawing of the shape of the further another shielding member applied to this invention. It is explanatory drawing (perspective view) of the shape of the other shielding member applied to this invention. It is a figure which shows the cooling fan of a prior art example. It is explanatory drawing of a predominate sound. It is explanatory drawing of the sound absorption characteristic of a porous sound-absorbing material.

  Embodiments of the present invention will be specifically described below.

(First embodiment)
FIG. 1 is a schematic view showing the vicinity of an engine of a hydraulic excavator as a work machine incorporating a cooling fan device according to a first embodiment of the present invention.

  The hydraulic excavator includes an engine 9 provided on the upper frame 2 of the upper swing body. On the upper frame 2, there are provided vertical plates as strength members over the entire length in the front-rear direction on both the left and right sides of the central portion in the left-right direction, and the left vertical plate 3 and the right vertical plate (not shown) An engine 9 is provided between them. This engine 9 has a turbocharger 14, and after the intake air Y 1 introduced from the air cleaner 15 is sent to the compressor 14 a of the turbocharger 14 through the intake pipe 16, where it is pressurized and cooled by the heat exchanger 12. Then, it is distributed to each cylinder via the intake manifold 17.

  Further, the exhaust gas Y2 discharged from each cylinder is sent to the turbine 14b of the turbocharger 14 via the exhaust manifold 18, and after driving the turbine 14b, is discharged outside the vehicle via the exhaust pipe 19.

  On the other hand, after a part of the exhaust gas Y2 exiting from the exhaust manifold 18 is extracted to the EGR pipe line 20 and air-cooled by the air-cooled EGR cooler 21, it is further water-cooled by the water-cooled EGR cooler 22 and cooled. Via the EGR valve (valve for adjusting the amount of recirculated gas) 23, the air is combined with the intake air cooled by the heat exchanger 12 and sent to the intake manifold 17 for recirculation. The heat exchanger 12 may include one or both of an oil cooler and an intercooler (not shown).

  Further, the cooling fan device 1 according to the first embodiment is provided between the engine 9 and the heat exchanger 12.

  The cooling fan device 1 includes a cooling fan 11 attached to a rotating shaft 9 a provided in the engine 9 and a shielding member 10 provided between the fan 11 and the engine 9. The fan 11 is rotationally driven by the rotating shaft 9 a and generates cooling air that passes through the heat exchanger 12 by sucking air from the leeward side of the heat exchanger 12.

  FIG. 2A is a side view showing the shielding member 10, and FIG. 2B is a front view showing the shielding member 10.

  The shielding member 10 includes a shielding wall 30 made of an annular plate material disposed so as to be substantially orthogonal to the cooling air flow direction Z (see FIGS. 1 and 2A) due to the rotation of the fan 11. A cylindrical peripheral wall 31 that rises from the outer peripheral portion 30 a of the shielding wall 30 toward the fan 11, and an air layer 32 is formed between the peripheral wall 31 and the shielding wall 30. It has an annular perforated plate 33 and a cylindrical member 34 through which the rotary shaft 9a is inserted. One end 34 a of the cylindrical member 34 is connected to an insertion hole 30 b provided in the center of the shielding wall 30, and the other end 34 b of the cylindrical member 34 is connected to an insertion hole 33 b provided in the center of the perforated plate 33. .

  The inner diameter of the cylindrical member 34 and the inner diameters of the insertion holes 30b and 33b are set to values close to the outer diameter of the rotating shaft 9a, and the gap between the cylindrical member 34 and the rotating shaft 9a is narrowed. . In addition, four partition members 35 are provided radially inside the shielding member 10. Specifically, each partition member 35 is disposed between the peripheral wall 31 and the cylindrical member 34 at a position that divides the annular air layer 32 between them into four equal parts. Each partition member 35 partitions the air layer 32 in a direction (circumferential direction of the rotating shaft 9a) orthogonal to the direction in which the shielding wall 30 and the perforated plate 33 are arranged. Further, the shielding member 10 is supported by the engine 9 via a support tool (not shown).

  A plurality of through holes 33 a are formed in the perforated plate 33. The through holes 33a are formed as circular holes, for example, and all have the same diameter.

  The thickness A of the perforated plate 33, the diameter (size) B of the through hole 33a of the perforated plate 33, the aperture ratio C of the perforated plate 33, and the thickness of the perforated plate 33 in the air layer 32 on the shielding wall 30 side. D is a parameter contributing to the sound absorption of the dominant sound, and the values of these parameters A to D are set so as to absorb one type of the dominant sound unique to the rotation of the fan 11. The

  By the way, the appropriate ranges of the parameters A to D are as follows. The thickness A of the perforated plate is preferably about 0.5 to 3 mm in consideration of strength. The size B of the through hole is preferably selected such that the diameter is about 0.1 to 5 mm when the through hole is circular, and has a similar opening area when the through hole has another shape. The The aperture ratio C of the perforated plate is preferably about 0.1 to 5%. The thickness D in the air layer on the shielding wall side of the perforated plate is preferably about 10 to 50 mm. As for the size B of the through hole, heat is generated on the inner peripheral surface of the through hole by the wind passing through the through hole, and vortex is generated on the exit side (inside the perforated plate) from the through hole. It is desirable to have dimensions that cause a phenomenon such as noise reduction.

  These four parameters A to D have the following characteristics and are related to each other.

  Regarding the plate thickness A of the perforated plate, when the plate thickness A is increased under the condition that the other parameters B, C, and D are the same, the frequency at which the sound absorption rate increases is decreased, and when the plate thickness A is decreased, The frequency at which the sound absorption coefficient increases becomes higher. With respect to the aperture ratio C of the perforated plate, when the aperture ratio C of the perforated plate is increased under the condition that the other parameters A, B, and D are the same, the frequency at which the sound absorption coefficient increases is increased. When the aperture ratio C is decreased, the frequency at which the sound absorption coefficient is increased is decreased. Regarding the size B of the through hole, if the size B of the through hole is increased under the condition that the other parameters A, C, and D are the same, the frequency at which the sound absorption rate is increased is decreased and the sound absorption rate is also decreased. . On the other hand, when the size B of the through hole is reduced, the frequency at which the sound absorption coefficient is increased is increased. Regarding the thickness D of the air layer on the shielding wall side of the perforated plate, when the thickness D of the air layer is increased under the condition that the other parameters A, B, and C are the same, the frequency at which the sound absorption coefficient increases becomes lower. Thus, when the thickness D of the air layer is reduced, the frequency at which the sound absorption rate increases is increased.

  In consideration of the above characteristics and an appropriate range, the four parameters A to D are determined so that the shielding member 10 has a sound absorption characteristic that absorbs one of a plurality of kinds of prevailing sounds generated by the rotation of the fan. It will be.

  FIG. 3 is a diagram showing a sound absorption characteristic (shown by a solid line) of the shielding member 10, wherein the horizontal axis represents frequency and the vertical axis represents sound absorption rate (%). In FIG. 3, the sound absorption characteristics when the above-described porous sound absorbing material is attached to the shielding wall 30 are indicated by a one-dot chain line.

  As understood from FIG. 3, the sound absorption characteristic of the shielding member 10 in the first embodiment is that the sound absorption rate changes steeply in the vicinity of the frequency F, and the frequency F is set to the peak sound absorption rate (100%). It has become. This frequency F corresponds to the frequency of one kind of dominant sound generated from the rotation of the fan 11 and the shielding member 10 absorbs the dominant sound of this frequency. Become. Therefore, in the case where the porous sound-absorbing material is attached to the shielding wall 30, the sound-absorbing characteristic in which the sound-absorbing rate increases linearly with increasing frequency cannot sufficiently absorb the dominant sound. The shielding member 10 according to the embodiment can sufficiently absorb the dominant sound.

  Therefore, in 1st Embodiment, in addition to being able to obtain sufficient sound absorption performance with respect to the prevailing sound resulting from rotation of the fan 11 as mentioned above, there exist the following effects. That is, the shielding member 10 is disposed on the leeward side of the fan 11 that generates the cooling air passing through the heat exchanger 12, and the shielding member 10 is generated from the leeward side of the fan 11 toward the fan 11. Since the entrainment air is prevented, the air volume can be increased accordingly, and the cooling efficiency can be increased. Moreover, the air flow around the fan 11 is made smooth by preventing the entrainment wind, thereby reducing turbulent noise. Furthermore, since the perforated plate 33 and the air layer 32 for efficiently absorbing the prevailing sound are incorporated in the shielding member 10, the surroundings of the fan 11 are not complicated. Furthermore, since each partition member 35 partitions the air layer 32 in a direction orthogonal to the direction in which the shielding wall 30 and the perforated plate 33 are arranged, the respective air layers 32a, 32b, 32c, and 32d that have become smaller by partitioning (see FIG. 2 (b)), the spherical wave can be brought close to the plane wave, and the sound absorbing performance can be sufficiently exhibited.

  In addition, although the partition member 35 is arrange | positioned in the position which divides the annular | circular shaped air layer 32 into four equal parts, this invention is not limited to this, Two, three, or five annular | circular shaped air layers 32 are provided. You may arrange | position so that it may divide into two or more equally or equally.

(Second Embodiment)
FIG. 4A is a side view showing the shielding member 10A in the cooling fan device according to the second embodiment, and FIG. 4B is a front view showing the shielding member 10A. In FIG. 4, the same parts as those in FIG. 2 are denoted by the same reference numerals.

  In the shielding member 10A, a first perforated plate 331 and a second perforated plate 332 are provided between the peripheral wall 31 and the cylindrical member 34 in parallel with the shielding wall 30, and the first perforated plate 331 and the second perforated plate 331 are provided. The perforated plate 332 has the same outer diameter. Here, the first perforated plate 331 closer to the shielding wall 30 is called the first perforated plate, the second perforated plate 332 farther from the shielding wall 30 is called the second perforated plate, and the first The air layer between the perforated plate 331 and the shielding wall 30 is the first air layer 321, and the air layer between the first perforated plate 331 and the second perforated plate 332 is the second air layer. Called 322.

  In addition, a total of eight partition members are provided inside the shielding member 10A. Specifically, each partition member 351 is disposed between the shielding wall 30 and the first perforated plate 331 and the first air layer 321 therebetween is divided into four equal parts, The partition member 351 partitions the first air layer 321 in a direction perpendicular to the direction in which the shielding wall 30 and the first perforated plate 331 are aligned (the circumferential direction of the rotation shaft 9a). Each partition member 352 is disposed at a position between the first perforated plate 331 and the second perforated plate 332 and dividing the second air layer 322 between them into four equal parts, Each partition member 352 partitions the second air layer 322 in a direction perpendicular to the direction in which the first perforated plate 35 and the second perforated plate 33 are aligned (the circumferential direction of the rotating shaft 9a).

  A plurality of through holes 331a are formed in the first perforated plate 331, and each through hole 331a is formed in, for example, a circular hole and has the same diameter. Then, the thickness A1 of the first perforated plate 331, the size B1 and the opening ratio C1 of the through hole 331a, and the thickness D1 of the first air layer 321 on the shielding wall 30 side of the first perforated plate 331. However, it is set so as to absorb one kind (for example, primary) of the dominant sounds unique to the fan 11. In addition, a plurality of through holes 332a are also formed in the second perforated plate 332, and each through hole 332a is formed in, for example, a circular hole and has the same diameter. The thickness A2 of the second perforated plate 332, the size B2 and the opening ratio C2 of the through hole 332a, and the thickness D2 of the second air layer 322 on the shielding wall 30 side of the second perforated plate 332 are provided. However, it is set so as to absorb another type (for example, secondary) of the dominant sound having a frequency different from that of the primary dominant sound among the plurality of dominant sounds unique to the fan 11.

  The parameters A1 to D1 and the parameters A2 to D2 described above are selected in consideration of characteristics that change in the same appropriate range as the parameters A to D described above and change in the same manner.

  FIG. 5 is a diagram showing a sound absorption characteristic (shown by a solid line) of the shielding member 10A, where the horizontal axis represents frequency and the vertical axis represents sound absorption rate (%).

  As can be understood from FIG. 5, the sound absorption characteristics of the shielding member 10A in the second embodiment are such that the sound absorption rate changes steeply in the vicinity of the frequency G and the frequency G is set to the peak sound absorption rate (96%). The sound absorption rate changes sharply in the vicinity of the frequency H, and the frequency H is set to the peak sound absorption rate (98%).

  The frequency G coincides with the frequency of one type (primary) of the dominant sound generated as the fan 11 rotates, and the primary dominant sound of this frequency is 1 The portion constituted by the th-perforated plate 331 and the first air layer 321 absorbs the portion. Further, the frequency H matches the frequency of one type (secondary) of the dominant sound generated by the rotation of the fan 11, and the secondary dominant sound of this frequency. Is absorbed by the portion formed by the second perforated plate 332 and the second air layer 322.

  Therefore, in the shielding member 10 </ b> A in the second embodiment, it is possible to sufficiently absorb each of the two primary sounds of the primary and secondary. Further, in the second embodiment, the shielding member 10A is disposed on the leeward side of the fan 11 that generates the cooling air passing through the heat exchanger 12, and the shielding member 10A is disposed on the leeward side of the fan 11. Since the entrainment wind generated toward the fan 11 is prevented, the air volume can be increased accordingly, and the cooling efficiency can be increased. Moreover, the air flow around the fan 11 is made smooth by preventing the entrainment wind, thereby reducing turbulent noise. Furthermore, since the perforated plates 331 and 332 and the air layers 321 and 322 for efficiently absorbing the prevailing sound are incorporated in the shielding member 10A, there is no complicated structure around the fan 11. . Furthermore, the partition members 351 and 352 partition the air layers 321 and 322 in a direction (circumferential direction of the rotating shaft 9a) perpendicular to the direction in which the shielding wall 30 and the perforated plate 331 (332) are arranged. In each of the air layers 321a, 321b, 321c, and 321d (see FIG. 4B) of the air layer 321 that has become smaller, it becomes possible to bring the spherical wave closer to a plane wave, and each of the air layers 322 that have been partitioned and made smaller In the air layers 322a, 322b, 322c, and 322d (see FIG. 4B), the spherical wave can be brought close to a plane wave, and the sound absorbing performance can be sufficiently exhibited.

  The partition members 351 and 352 are disposed at positions that divide the annular air layers 321 and 322 into four equal parts. However, the present invention is not limited to this, and the annular air layers 321 and 322 are disposed at two positions. It may be arranged so as to be divided into three or three or five or more or equally divided. Further, the number of the partition members 351 used may be different from the number of the partition members 352 used. Furthermore, the position where the partition member 351 is disposed (position in the circumferential direction of the rotating shaft 9a) and the partition member 352 are disposed. May be different from the position (the position in the circumferential direction of the rotating shaft 9a). Furthermore, the partition members 351 and 352 do not need to be arranged radially, for example, as shown in FIG. 6, the partition members 351A and 352A that are further parallel to the radially arranged partition members 351 and 352 may be added, Alternatively, the partition members 351 and 352 arranged radially from the arrangement state shown in FIG. 6 may be omitted, or may be arranged so that each one is directed in an arbitrary direction although illustration is omitted. The arrangement of the partition member is similarly applied to the partition member of the first embodiment. In the arrangement of the partition members as described above, the size of the air layer partitioned by the partition member can be adjusted by changing the number of partitioning the air layers. Can be brought close to a plane wave, and the sound absorbing performance can be sufficiently exhibited.

  In the second embodiment described above, the primary perforated sound is absorbed by the first perforated plate 331 and the first air layer 321, and the second perforated plate 332 and the second air layer 322 are used. However, the present invention is not limited to this, and the first perforated plate 331 and the first air layer 321 absorb other prevailing sounds other than the primary sound. The second perforated plate 332 and the second air layer 322 may be configured to absorb other dominant sounds other than the secondary sounds.

  Furthermore, in 2nd Embodiment mentioned above, although it is set as the structure which provides the two perforated plates 331 and 332 and the two air layers 321 and 322 inside the surrounding wall 31, this invention is not limited to this, The surrounding wall 31 of It is also possible to employ a configuration in which three or more perforated plates and the same number of air layers as the perforated plates are provided on the inner side.

  In the case of this configuration, it includes N perforated plates (N is an arbitrary integer equal to or greater than 3) perforated plates that are spaced apart from each other in the rising direction of the perimeter wall 31 inside the perimeter wall 31, Among the perforated plates closest to the shielding wall 30, the first air layer is formed between the shielding wall 30 and the nth hole (n is an arbitrary integer of 3 or more and N or less) counted from the shielding wall 30. The aperture plate forms an n-th air layer with the (n-1) -th aperture plate counted from the shield wall 30, and any one of the N air layers and the N shield walls is selected. N sets of air layers and perforated plates, each having one air layer and a perforated plate closest to the air layer and far from the shielding wall 30, each absorbs a dominant sound having a different frequency. The thickness of the perforated plate in each set, the size and opening ratio of the through holes, and the thickness of the air layer There is set.

  Furthermore, in the first and second embodiments described above, the cylindrical member 34 is provided in the center of the shielding members 10 and 10A, and the inside of the cylindrical member 34 is inserted through the rotary shaft 9a. Is not limited to this. When the rotation shaft 9a is not used for the rotation drive of the fan 11, for example, when the rotation of the fan 11 is driven by a belt, the cylindrical member 34 is unnecessary as shown in FIG. In this case, the partition plates 321 and 322 can be arranged up to the center of the shielding member 10A. FIG. 7 illustrates the shielding member 10A of the second embodiment as an example, but this is the same for the shielding member 10 of the first embodiment.

  FIG. 8 is a perspective view showing a shielding member applied to the work machine of the present invention. The shielding member 10B has a disc-shaped shielding wall 30B having a concave portion 30B1 on the outer peripheral portion, and a disc-shaped perforated plate 33B formed in the same shape as the shielding wall 30B and having a concave portion 33B1 on the outer peripheral portion. And a peripheral wall 31B having a constant width connected to the outer periphery of the shielding wall 30B and the perforated plate 33B. The concave portion 30B1 of the shielding wall 30B and the concave portion 33B1 of the perforated plate 33B are aligned in the same direction, and the peripheral wall 31B has a concave portion 30B1 and a portion 31B1 connected to the concave portion 30B1, and the other portion 31B2 has a concave shape. It has an arc shape. The other arc-shaped portion 31B2 is arranged such that its center coincides with the rotation center of the fan 11, and the outer periphery of the shielding member 10B is an arc-shaped portion having an arc shape centered on the rotation center of the fan. 10 </ b> B <b> 2 and a concave portion 10 </ b> B <b> 1 that is recessed more radially inward than the arc-shaped portion 10 </ b> B <b> 2.

  In the case of this shielding member 10B, for example, even if the EGR pipeline 20 passes through the vicinity of the location where the shielding member 10B is disposed (see FIG. 1), by passing the EGR pipeline 20 inside the concave portion 10B1, The shielding member 10B can be installed while avoiding interference with the EGR pipe line 20. As a result, the cooling fan device can be installed without changing the periphery of the engine of the hydraulic excavator as the work machine.

  In the above-described embodiment, an example in which a cooling fan device is installed in the heat exchanger 12 of the excavator is described. However, other construction machines other than the excavator and other work machines (for example, special machines) The same can be applied to a vehicle or the like. In addition to the working machine, the cooling fan device of the present invention can be installed for a heat exchanger provided in an automobile, an air conditioner outdoor unit, or the like.

DESCRIPTION OF SYMBOLS 1 Cooling fan apparatus 10, 10A, 10B Shield member 11 Fan 12 Heat exchanger 30 Shield wall 31 Perimeter wall 32 Air layer 33 Perforated plate 33a Through hole 35 Partition member 321 1st air layer 322 2nd air layer 331 1st Perforated plate 332 Second perforated plate 331a, 332a Through hole 351, 352, 351A, 352A Partition member

Claims (5)

A cooling fan device for cooling the heat exchanger,
A fan that is provided to face the heat exchanger and generates cooling air that passes through the heat exchanger by sucking air from the leeward side of the heat exchanger by rotating;
A shielding member that is provided on the opposite side of the heat exchanger across the fan, and is arranged so as to prevent the wind from the leeward side of the fan toward the fan,
The shielding member includes a shielding wall that is arranged so as to be substantially orthogonal to the flow direction of the cooling air generated by the rotation of the fan, a peripheral wall that rises from the outer periphery of the shielding wall toward the fan, and an inner side of the peripheral wall. A perforated plate disposed to form an air layer with the shielding wall,
The perforated plate is formed with a plurality of through holes, and the thickness of the perforated plate, the size and the opening ratio of the through holes, and the thickness of the air layer on the shielding wall side of the perforated plate are determined by the fan. A cooling fan device, which is set to absorb one type of prevailing sound among a plurality of prevailing sounds unique to. A cooling fan device for cooling the heat exchanger,
A fan that is provided to face the heat exchanger and generates cooling air that passes through the heat exchanger by sucking air from the leeward side of the heat exchanger by rotating;
A shielding member that is provided on the opposite side of the heat exchanger across the fan, and is arranged so as to prevent the wind from the leeward side of the fan toward the fan,
The shielding member includes a shielding wall that is arranged so as to be substantially orthogonal to the flow direction of the cooling air by the rotation of the fan, a peripheral wall that rises from the outer periphery of the shielding wall toward the fan, and an inner side of the peripheral wall. N perforated plates (N is an arbitrary integer greater than or equal to 2) perforated plates arranged at intervals in the rising direction of the peripheral wall, and among these perforated plates, the perforated plate closest to the shielding wall Forms a first air layer between itself and the shielding wall, and the nth perforated plate (n is an arbitrary integer of 2 or more and N or less) counted from the shielding wall is counted from the shielding wall (n -1) An nth air layer is formed between the first perforated plate and any one of these N air layers and N shielding walls is closest to the air layer and the air layer. In addition, N sets of air layers and perforations with a perforated plate on the side far from the shielding wall as one set Cooling characterized in that the plate thickness of the perforated plate, the size and opening ratio of the perforated holes, and the thickness of the air layer in each set are set so that the plates absorb the dominant sounds having different frequencies. Fan device. The cooling fan device according to claim 1,
The cooling fan device according to claim 1, wherein the shielding member further includes a partition member that partitions the air layer in a direction orthogonal to an arrangement direction of the shielding wall and the perforated plate. The cooling fan device according to claim 2,
The cooling member device further includes a partition member that partitions at least one air layer in a direction orthogonal to an arrangement direction of the shielding wall and the perforated plate. A work machine equipped with a heat exchanger and the cooling fan device according to any one of claims 1 to 4 for cooling the heat exchanger,
The outer periphery of the shielding member in the cooling fan device has the arc shape so as to avoid interference between an arcuate portion having an arc shape centered on the rotation center of the fan and a member disposed in the vicinity of the shielding member. A work machine comprising: a concave portion that is recessed inward in the radial direction from the portion.

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