JP2012097682A - Fan shroud structure of cooling fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fan shroud structure of a cooling fan which exhibits a noise prevention effect while overcoming a safety problem.SOLUTION: The fan shroud structure houses a part or the whole of the cooling fan 10. First to fifth openings 31-35 that allow a space P1 in the fan shroud 20 to communicate with a space P2 outside the fan shroud 20 are provided in the fan shroud 20. First to fifth sound absorptive materials 41-45 are mounted at positions corresponding respectively to the first to fifth openings 31-35 from the outside of the fan shroud 20.

Description

  The present invention relates to a fan shroud structure of a cooling fan.

  In construction machines and work machines, a structure in which a cooling fan is disposed between an engine and a radiator is widely used. A part or all of the cooling fan is accommodated in the fan shroud. The fan shroud surrounds the vicinity of the outer periphery of the blade of the cooling fan so as to define an air passage and guide the drawn air to efficiently pass through the radiator.

  Noise generated from the vicinity of the cooling fan can be attenuated to some extent (with engine sound and the like) by a sound absorbing material attached to the inside of the house or engine hood. However, the effect is limited.

  Patent Document 1 discloses a configuration in which a porous sound absorbing material is disposed inside the fan shroud itself in order to reduce noise in the vicinity of the cooling fan.

JP 2002-332843 A

  However, if the sound absorbing material is arranged “inside” the fan shroud, the bolts for fixing the sound absorbing material will fall loose, or if the deteriorated sound absorbing material is peeled off, the rotating cooling fan There is a risk of collision with the blade, or a bolt or the like bounced by the blade may collide with the radiator again. Therefore, it cannot be said that it is preferable for safety.

  However, when a sound absorbing material is attached to the “outside” of the fan shroud, the actual situation is that a noise reduction effect is hardly obtained.

  The present invention has been made to solve such a problem, and an object thereof is to provide a fan shroud structure of a cooling fan having a high noise prevention effect while clearing a safety problem.

  The present invention provides a fan shroud structure that accommodates part or all of a cooling fan, wherein the fan shroud is provided with an opening that allows communication between an inner space and an outer space of the fan shroud, and corresponds to the opening. By adopting a configuration in which a sound absorbing material is attached to the position from the outside of the fan shroud, the above problem has been solved.

  When the fan shroud is physically vibrated by strong acoustic energy, it is difficult to suppress this vibration by a sound absorbing material attached to the outside of the fan shroud. This is considered to be the reason that the noise reduction effect is hardly obtained even if the sound absorbing material is disposed outside the fan shroud.

  In the present invention, this mechanism is used in reverse, and an opening (an opening that connects the space inside the fan shroud and the space outside) is intentionally formed in the fan shroud. Thereby, a part of the acoustic energy applied to the fan shroud can be released to the outside of the fan shroud through the opening, so that the fan shroud itself does not receive a high sound pressure and vibration is suppressed. On the other hand, the acoustic energy guided outside the fan shroud is effectively absorbed (sound absorption) by the sound absorbing material disposed at a position corresponding to the opening.

  In the present invention, since the sound absorbing material is attached to the “outside” of the fan shroud, the bolt fixing the sound absorbing material should fall loose, or the sound absorbing material may deteriorate and partly peel off. There is no risk of collision with the cooling fan blades, which is extremely safe.

  In the present invention, for example, the opening may be constituted by a plurality of small holes. As a result, a large opening area can be ensured without reducing the strength of the fan shroud. Moreover, it is possible to prevent the bolts and the like from falling into the fan shroud more reliably.

  Further, a sound absorbing material cover capable of holding the sound absorbing material may be provided, and the sound absorbing material may be attached to a position corresponding to the opening of the fan shroud via the sound absorbing material cover. According to this configuration, not only can the sound absorbing material be securely fixed by the sound absorbing material cover, but the presence of the sound absorbing material cover further prevents the acoustic energy that has passed through the sound absorbing material from being diffused into the engine room. Can be suppressed.

  In addition, when employ | adopting the structure provided with the sound-absorbing material cover which can hold | maintain such a sound-absorbing material, the attachment structure which this sound-absorbing material cover does not touch a fan shroud directly can also be employ | adopted. This merit will be described later. The sound absorbing material cover can be attached without directly touching the fan shroud. The sound absorbing material cover can be attached to the fan shroud via a cushioning material (vibration absorbing material) or to a structure other than the fan shroud (for example, a radiator hood). A configuration to be attached is conceivable.

  ADVANTAGE OF THE INVENTION According to this invention, the fan shroud structure of a cooling fan with a high noise prevention effect can be obtained, clearing a safety problem.

The partially exploded perspective view which showed the fan shroud structure of the cooling fan which concerns on embodiment of this invention Partial sectional view showing a modification of the embodiment

  Hereinafter, an example of an embodiment of the present invention will be described in detail based on the drawings.

  FIG. 1 is a partially exploded perspective view showing a fan shroud structure of a cooling fan of a construction machine according to an example of an embodiment of the present invention.

  The fan shroud structure A1 of the cooling fan is applied to a water-cooled cooling system. The present invention can also be applied to an air-cooled cooling system. In this cooling system, a cooling fan 10 is arranged opposite to the radiator 8 that performs heat exchange. The cooling fan 10 is driven by the rotation of an engine (not shown).

  A fan shroud 20 is disposed on the outer periphery of the cooling fan 10. The fan shroud 20 includes four side surfaces 22 (first and second horizontal surfaces 22A and 22B and first and second vertical surfaces 22C and 22D) formed substantially parallel to the rotation axis R1 of the cooling fan 10, and the four It is mainly composed of an elevation surface 24 formed in contact with the side surface 22 and perpendicular to the rotation axis R1.

  Mounting flange portions 26 are bent and extended on the four side surfaces 22 of the fan shroud 20 (only the flange portion 26 of the first vertical surface 22C is shown), and bolt holes formed in these flange portions 26 are formed. 28, the entire fan shroud 20 is fixed to the hood 8 </ b> A of the radiator 8.

  The vertical surface 24 of the fan shroud 20 is formed with a large circular vent 24 </ b> A for allowing air to flow into the cooling fan 10 side. In the case of a cooling system that draws air to the cooling fan side via the radiator 8, the ventilation port 24A serves as an air outlet.

  In this type of fan shroud 20, if the clearance δ between the air vent 24 </ b> A of the fan shroud 20 and the outer peripheral end of the blade 10 </ b> A of the cooling fan 10 is set small, the air passage efficiency of the radiator 8 can be further increased. . However, in this case, since the space between the inside of the fan shroud 20 and the outer periphery of the cooling fan 10 is substantially closed, the air pressure variation in the space due to the rotation of the blade 10A is large. The generated acoustic energy tends to increase.

  Therefore, in this embodiment, the following configuration is adopted.

  Although not all are shown in FIG. 1 for convenience of illustration, in this embodiment, four side surfaces 22 (first and second horizontal surfaces 22A and 22B and first and second vertical surfaces 22C) of the fan shroud 20 are used. 22D), a total of five first to fifth openings 31 to 35 (only the second and fourth openings 32 and 34 are shown) are formed, and each "position corresponding to the openings 31 to 35" First to fifth sound absorbing materials 41 to 45 (only the first to fourth sound absorbing materials 41 to 44 are shown) are respectively attached from the outside of the fan shroud 20. In this embodiment, the first to fifth sound absorbing materials 41 to 45 are attached via the first to fifth sound absorbing materials covers 51 to 55 that can hold the first to fifth sound absorbing materials 41 to 45, respectively. It has been broken. In FIG. 1, only the second sound absorbing material cover 52 is depicted in a disassembled state (a state suspended in the air) in order to facilitate understanding of the configuration before attachment.

  The first to fifth openings 31 to 35 are respectively constituted by a plurality of small holes 31A to 35A (only the small holes 32A and 34A constituting the second and fourth openings 32 and 34 are shown), and cooling the fan shroud 20 The space inside the fan 10 (the space on the side where the cooling fan 10 is located) P1 communicates with the outside space P2. The reason why the first to fifth openings 31 to 35 are configured by such a large number of small holes 31A to 35A is to secure an opening area as large as possible without reducing the strength of the fan shroud 20. . Thereby, the sound pressure inside the fan shroud 20 is effectively reduced to suppress the vibration of the fan shroud 20, and the first to fifth sound absorbing materials 41 to 45 disposed outside the fan shroud 20 are more. Can be absorbed. Further, since the areas of the small holes 31A to 35A are kept small, even if the first to fifth sound absorbing materials 41 to 45 are deteriorated due to changes over time (not to mention bolts), the fan The effect that it does not peel off inside the shroud 20 is also obtained.

  As said 1st-5th sound-absorbing materials 41-45, porous materials, such as glass wool and urethane foam, are employable, for example. In the present invention, the materials themselves of the first to fifth sound absorbing materials 41 to 45 are not particularly limited.

  The first to fifth sound absorbing material covers 51 to 55 are integrally formed from the box portions 51B to 55B (only the box portions 51B to 54B of the first to fourth sound absorbing material covers are shown) and the box portions 51B to 55B, respectively. It is mainly comprised from the extended attaching parts 51E-55E.

  More specifically, each box part 51B-55B of the 1st-5th sound-absorbing material covers 51-55 can each accommodate the 1st-5th sound-absorbing materials 41-45 (in the example of embodiment, it is a substantially rectangular parallelepiped). ). Moreover, each attachment part 51E-55E protrudes in the shape of an ear piece from box part 51B-55B, and the some bolt hole 51H at the time of fixing the 1st-5th sound-absorbing-material cover 51-55 to the fan shroud 20 is carried out. To 55H are formed (the bolt holes 54H of the fourth sound absorbing material cover 54 are not shown).

  On the fan shroud 20 side, a nut portion 60 formed with an internal thread is provided at a position corresponding to the bolt holes 51H to 55H of the mounting portions 51E to 55E of the first to fifth sound absorbing material covers 51 to 55. (Only the nut portion 60 corresponding to the bolt hole 52H of the second sound absorbing material cover 52 is shown).

  The first to fifth sound absorbing material covers 51 to 55 are bolts (not shown) (bolt holes 51H of the mounting portions 51E to 55E) in a state where the first to fifth sound absorbing materials 41 to 45 are accommodated in the box portions 51B to 55B, respectively. It is attached to the fan shroud 20 by screwing into the nut portion 60 (through ~ 55H). As a result, the first to fifth sound absorbing materials 41 to 45 are attached to the positions corresponding to the first to fifth openings 31 to 35 of the fan shroud 20, respectively.

  Next, the operation of the fan shroud structure of the cooling fan 10 will be described.

  When the cooling fan 10 is rotated by the rotation of the engine, air is sent from the rear of the cooling fan 10 (the right side in FIG. 1) to the radiator 8 side, and heat exchange is performed by the radiator 8. The basic action of the cooling system itself is not particularly different from the conventional one.

  When the cooling fan 10 rotates, in addition to the rotation sound of the cooling fan 10 itself, the airflow sound of the air due to the rotation of each blade 10A, etc. is converted into acoustic energy (sound pressure: air pressure fluctuation energy) as the fan shroud 20. It hangs on the inside surface.

  If no soundproofing measures are taken for the fan shroud 20, this acoustic energy causes the fan shroud 20 to vibrate and causes an increase in noise. However, according to the present embodiment, since the sound pressure can be released to the outside of the fan shroud 20 through the first to fifth openings 31 to 35 formed in the fan shroud 20, the sound pressure inside the fan shroud 20. And the vibration of the fan shroud itself can be effectively suppressed.

  On the other hand, first to fifth sound absorbing materials 41 to 45 are arranged at positions corresponding to the first to fifth openings 31 to 35, respectively. For this reason, the acoustic energy by the cooling fan 10 is transmitted to these first to fifth sound absorbing materials 41 to 45. When acoustic energy is transmitted to the first to fifth sound absorbing materials 41 to 45, viscous friction is generated by the movement of air through gaps or bubble portions inside the first to fifth sound absorbing materials 41 to 45, and the acoustic energy is increased. Is converted into thermal energy, and “sound absorption” is performed.

  In this embodiment, since the first to fifth sound absorbing materials 41 to 45 are placed in a state where they can directly receive air vibrations from the cooling fan 10 through the first to fifth openings 31 to 35, The original high sound absorbing action of the first to fifth sound absorbing materials 41 to 45 can be sufficiently exhibited (unlike when placed outside the shroud 20).

  In addition, since the first to fifth sound absorbing materials 41 to 45 themselves are covered by the first to fifth sound absorbing material covers 51 to 55, the first to fifth sound absorbing material covers 51 to 55 are also (first). The sound energy (which was not completely absorbed by the fifth sound absorbing materials 41 to 45) can be shut off again, and as a result, the noise level around the cooling fan 10 that diverges into the engine room can be greatly reduced.

  Above all, in the present embodiment, the first to fifth sound absorbing materials 41 to 45 are attached to the “outside” of the fan shroud 20. For this reason, the bolt which has fixed the 1st-5th sound-absorbing materials 41-45 should loosen and fall off, or a part of 1st-5th sound-absorbing materials 41-45 may deteriorate and may fall off. Even if a situation occurs, there is no fear that the bolts or part of the first to fifth sound absorbing materials 41 to 45 collide with the blade 10A of the cooling fan 10, and it is extremely safe. In particular, in the present embodiment, since the first to fifth openings 31 to 35 of the fan shroud 20 are constituted by a large number of small holes 31A to 35A, this “effect in terms of safety” is obtained more reliably. be able to.

  Various modifications can be considered in the present invention.

  For example, in the above-described embodiment, the first to fifth sound absorbing material covers 51 to 55 are directly fixed to the fan shroud 20, but for example, as shown in FIG. In some cases, noise reduction can be realized by mounting without directly touching 82. That is, in the embodiment of FIG. 1 (although the sound pressure inside the fan shroud 20 can be greatly reduced), the vibration of the fan shroud 20 is not necessarily completely suppressed. In this case, when the first to fifth sound absorbing material covers 51 to 55 are directly attached to the fan shroud 20 as in the example of FIG. 1, the vibration of the fan shroud 20 causes the first to fifth sound absorbing material covers 51 to 51. The first to fifth sound absorbing material covers 51 to 55 may vibrate together with the fan shroud 20 to form a “large area noise source”.

  In the embodiment shown in FIG. 2, the sound-absorbing material cover 80 is fixed to a structure other than the fan shroud 82 (for example, the radiator hood 8A), and for the fan shroud 82 (can absorb vibration). Abutting and fixing are performed via a buffer material 84. That is, the sound absorbing material cover 80 is attached so as not to directly touch the fan shroud 82.

  As a result, the sound-absorbing material cover 80 is not affected by the vibration of the fan shroud 82 (because it only needs to receive the sound pressure attenuated by the sound-absorbing material 88), even if the fan shroud 82 vibrates. , It will be possible to maintain a state that does not vibrate in conjunction. As a result, noise leaking into the engine hood P3 can be further reduced.

  In FIG. 2, reference numeral 86 </ b> A is a small hole constituting the opening 86, and 90 is a reinforcing portion of the sound absorbing material cover 80.

  Although not shown, as a further modification of the embodiment of FIG. 2, for example, the sound absorbing material cover (not fixed to the fan shroud at all) is placed only in the structure other than the fan shroud, for example, in a cantilever state. Even if it is fixed with, it can be attached without directly touching the fan shroud. Further, for example, if the sound absorbing material cover is attached via a cushioning material, the sound absorbing material cover can be attached without directly touching the fan shroud, even if the structure is fixed only to the fan shroud.

  In the above embodiment, the first to fifth openings 31 to 35 are configured by the plurality of small holes 31A to 35A. However, in the present invention, the way of forming the openings is particularly this example. It is not limited to. Further, the position where the opening is formed and the size and number of the openings are not particularly limited.

  Furthermore, in the said embodiment, although the 1st-5th sound-absorbing material 41-45 was attached via the 1st-5th sound-absorbing material cover 51-55, in this invention, how is a sound-absorbing material? There is no particular limitation as to whether or not it is attached. For example, when using a relatively hard sound-absorbing material, a configuration may be adopted in which it is attached via a fastener similar to a bolt and a large washer (without using a sound-absorbing material cover).

  Moreover, in the said embodiment, although the example of the fan shroud 20 which has four side surfaces 22 (1st, 2nd horizontal surface 22A, 22B and 1st, 2nd vertical surface 22C, 22D) near a plane was shown, In the present invention, the shape of the fan shroud is not particularly limited to such a shape. For example, the shape may have a substantially cylindrical side surface. In this case, it is preferable that the shape of the sound-absorbing material also has an inner side surface along the cylindrical side surface.

DESCRIPTION OF SYMBOLS 10 ... Cooling fan 20 ... Fan shroud 22 ... Side surface 24 ... Elevation surface 26 ... Flange part 31-35 ... 1st-5th opening 41-45 ... 1st-5th sound absorption material 51-55 ... 1st-5th sound absorption Material cover

Claims (6)

In the structure of the fan shroud that accommodates part or all of the cooling fan,
The fan shroud is provided with an opening that allows communication between the space inside the fan shroud and the space outside, and a sound absorbing material is attached to the position corresponding to the opening from the outside of the fan shroud. Fan shroud structure of cooling fan. In claim 1,
The fan shroud structure for a cooling fan, wherein the opening is constituted by a plurality of small holes. In claim 1 or 2,
Furthermore, a sound absorbing material cover capable of holding the sound absorbing material is provided,
A fan shroud structure for a cooling fan, wherein the sound absorbing material is attached to a position corresponding to the opening of the fan shroud through the sound absorbing material cover. In any one of Claims 1-3,
The fan shroud structure for a cooling fan, wherein the sound absorbing material cover is attached without directly touching the fan shroud. In claim 4,
A fan shroud structure for a cooling fan, wherein the sound absorbing material cover is attached to the fan shroud via a cushioning material. In claim 4 or 5,
A fan shroud structure for a cooling fan, wherein the sound absorbing material cover is attached to a structure other than the fan shroud.

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