JP2002332843A - Method of manufacturing fan shroud using porous sound- absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a fan shroud, using a porous sound absorbing material capable of providing favorable sound absorptivity, durability, and weather resistance and easy manufacture by excluding difficult heating condition setting or the like. SOLUTION: In manufacture of the fan shroud 20, particularly when manufacturing a sound-absorbing material body 34 of the porous sound-absorbing material 30, an outer surface 35 is provided by using a band saw 51 and removing a machining allowance portion 61 so porosity of a surface of foam 60 is not crushed. By this, the sound-absorbing characteristic in an outer surface 35 side facing a tip portion of a fan 3 can be improved, and favorable weather resistance and durability to rainwater and dust of the outer surface 35 can be provided, by covering it with a protective film sheet 40. Since it is unnecessary to melt and harden the outer surface 35, complicated settings can be dispensed with, and manufacture of the porous sound absorbing material 30 can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fan shroud using a porous sound-absorbing material, for example, an engine cooling system for special vehicles including construction machines such as power shovels and other vehicles, or various types of vehicles. The present invention relates to a noise reduction mechanism of a fan device for an industrial cooling system and an improvement of a method of manufacturing a fan shroud used for the same.

[0002]

BACKGROUND ART Conventionally, as an engine cooling system for a vehicle or the like, a system for circulating a coolant between an engine and a radiator has been known. In such a cooling system, a fan is mounted close to the radiator, heat is exchanged between the cooling air sucked by the fan and the coolant in the radiator, and the engine is cooled by the coolant after the heat exchange. ing. At this time, a fan shroud is provided around the fan, and by arranging the flow of cooling air passing through the radiator with the fan shroud, heat exchange in the radiator can be favorably performed, thereby improving the engine cooling efficiency. ing.

By the way, the present inventor disclosed in Japanese Patent Application Laid-Open No. 2000-3
No. 750, the inner surface of a fan shroud,
In other words, by forming the portion facing the rotation trajectory of the tip of the fan with a porous sound-absorbing material, we have proposed a proposal to effectively muffle the airflow noise generated between the fan shroud and the fan and reduce the noise reliably. ing.

In Japanese Patent Application No. 2000-231152, as a method for forming such a porous sound-absorbing material, for example, the surface of a quadrangular prism-shaped foam is heated and melted to face the rotation trajectory at the tip of the fan. It proposes to finish the part to the final shape. According to this molding method, a desired final shape can be easily molded, and since the surface is once melted and then cured, there is an advantage that weather resistance and durability are improved.

[0005]

However, when the surface portion facing the rotation trajectory of the fan is hardened by heating and melting, if the pressing deformation of the foam is increased and the foam is heated and formed, the porous portion can be deepened. There is a problem in that it is crushed and sufficient sound absorbing performance cannot be obtained. In addition, the necessary heating conditions during molding are determined by the size of the foam and the amount of deformation by pressing of the foam, but depending on the heating conditions, the hardened part due to thermal deterioration of the surface layer is rather brittle, so it is easily broken by the impact of dust and dust. For example, there is a problem that weather resistance and durability are also reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a fan shroud using a porous sound-absorbing material, which can provide good sound absorbing properties, durability and weather resistance, and can be easily manufactured without setting difficult heating conditions. Is to provide.

[0007]

According to the first aspect of the present invention, there is provided a method of manufacturing a fan shroud using a porous sound-absorbing material. A method of manufacturing a fan shroud using a porous sound-absorbing material, wherein at least a surface of a porous foam body facing a tip end side of the fan is formed without crushing a porous portion near a surface layer of the fan shroud. A processing step of obtaining a sound-absorbing material body by processing into a shape, and a step of covering at least a surface of the sound-absorbing material body processed into an inner surface shape of the fan shroud that faces the front end side of the fan with a protective film,
Attaching the sound absorbing material main body processed into the inner shape of the fan shroud to the mounting portion of the support member.

According to such a method, the sound absorbing material main body is obtained by processing the portion near the surface layer of the foam to be the base material so that the porous material is not crushed. Has improved sound absorbing properties, and good sound absorbing performance can be obtained. In addition, since the surface formed in this way is covered with a protective film, it has good weather resistance and durability against rainwater and sand dust without melting and hardening the surface or chemical treatment with chemicals as in the past. Demonstrate the nature. Further, complicated setting as in the related art is not required, and the manufacturing becomes easy.

According to a second aspect of the present invention, there is provided a method for manufacturing a fan shroud using a porous sound-absorbing material according to the first aspect of the present invention. After covering the surface of the fan facing the front end portion with a protective film, the sound absorbing material main body is attached to the attachment portion of the support member. According to such a method, the work of covering the sound absorbing material main body with the protective film becomes easy, and workability is improved.

According to a third aspect of the present invention, there is provided a method of manufacturing a fan shroud using a porous sound absorbing material according to the first or second aspect. The mounting portion of the support member to which the main body is mounted is formed in a cylindrical shape. In such a method, since the mounting portion of the support member is formed in a cylindrical shape, the sound absorbing material main body may be mounted on the flat inner peripheral surface of the mounting portion, and the workability is further improved. In addition, since the mounting portion is formed in a simple cylindrical shape, it is not necessary to form the mounting portion by injection molding for a mold, complicated roll processing, or the like, thereby reducing the manufacturing cost of the support member.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a fan shroud using a porous sound absorbing material according to any one of the first to third aspects. The inner shape of the fan shroud is bell-mouth-shaped. In such a method, the inner surface of the fan shroud is formed in a bell mouth shape, so that the cooling air flows smoothly between the front end side of the fan and the porous sound absorbing material, and the generated airflow noise is significantly reduced. As a result, the sound absorption performance is remarkably improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged view showing a main part of an example in which a fan shroud manufactured by the manufacturing method according to the present embodiment is applied to an engine cooling system 1 of a construction machine such as a power shovel.

The engine cooling system 1 circulates a coolant between an engine (not shown) and the radiator 2, and cools the engine with the coolant exchanged by the radiator 2. The engine is cooled between the engine and the radiator 2. ,
A fan 3 for sucking cooling air for heat exchange is arranged. The fan 3 is driven to rotate by an output transmitted from a crankshaft of the engine by a pulley and a fan belt. A radiator hood 10 and a fan shroud 20 are provided downstream of the radiator 2.

The radiator hood 10 is made of, for example, a sheet metal, and has a shape including a square tube or a partially cylindrical shape having an outer flange 11 provided at an end on the downstream side, and a bolt on the radiator 3 side on the upstream side. And are fixed with nuts and the like.

The fan shroud 20 is connected to the outer flange 11.
Metal or resin shroud support member (hereinafter, referred to as a support member) 21 fixed by bolts and nuts, and a sound absorbing member made of, for example, urethane resin attached to a large opening provided in the center of the support member 21. Material or a porous (porous) sound absorbing material 30 made of a sound absorbing material made of polyethylene terephthalate (PET) fiber
It is composed of

The support member 21 of the fan shroud 20 has a simple structure in which a strip-shaped metal plate is formed in a cylindrical shape and the ends are connected to each other by welding or the like. Vertical support piece 23 for supporting
And rising pieces 24 formed on both the upstream and downstream edges of the mounting section 22.
2 has a U-shaped cross section.

As shown in FIG. 2D, a plurality of (four to six) porous sound absorbing members 30 are suitably attached to the inner peripheral surface of the mounting portion 22 constituting the supporting member 21. In this embodiment, four (4) porous members 31 are provided.

As will be described later, the porous member 31 is manufactured by processing a quadrangular prism-shaped foam 60 (FIG. 2A), and has a bell mouth shape opening toward the upstream side. A sound absorbing material main body 34 having a substantially semi-elliptical cross section is provided with an upstream opening 32 and a downstream opening 33 opened in a bell mouth shape toward the downstream side.

The outer surface 35 of the sound absorbing material body 34 facing the tip of the fan 3 forms a curved surface of a semi-elliptical portion, and forms the inner shape of the fan shroud 20. A vertical surface 36 is formed on the upstream and downstream sides of the outer surface 35 so as to be covered with the rising pieces 24 of the support member 21, and a mounting surface 37 for attaching to the mounting portion 22 is provided between the vertical surfaces 36. Is formed.

The sound absorbing material body 34 allows the fan 3
The airflow noise and the impact noise of the cooling air generated between the tip side of the fan and the fan shroud 20 are reduced, and the openings 32 and 33 of the porous member 31 are made bell-mouth-shaped, so that the cooling air is supplied to the fan. 3 and the fan shroud 20.

The sound absorbing material body 34 has an outer surface 3
5 and a protective film sheet 40 covering the vertical surface 36 are attached by bonding or the like. As the protective film sheet 40, an acrylic sheet, a polyurethane sheet, a hot-melt sheet of polyurethane foam, a cross sheet, and the like are employed. Among them, a cross sheet of polyester resin fiber, a cross sheet of aluminum glass fiber, A cross sheet of acrylic resin fibers, a cross sheet of polyurethane resin fibers, and the like are preferably used.

Next, a method of manufacturing the fan shroud 20 using the porous sound absorbing material 30 will be described with reference to FIGS. In FIG. 2A, first, a foam body 60 serving as a base material of the sound absorbing material main body 34 is prepared. This foam body 60 has a rectangular column shape having the same width dimension W ₁ as the width dimension W ₂ (FIG. 1) of the mounting portion 22 of the support member 21 and a sufficient height dimension H ₁ in consideration of the processing margin portion 61. It has been. The length of the foam body 60 may be the same as the sound absorbing material body 34 from the beginning, but may be cut later to match the length of the sound absorbing material body 34.

Next, in FIG. 2 (B), the processing margin portion 61 of the foam 60 is removed by machining using a band sawing machine provided with an endless band saw 51 to obtain a sound absorbing material main body 34.
At this time, with respect to the band saw 51 moving in the direction of the arrow a, the foam 60 is positioned so that the moving direction and the longitudinal direction coincide with each other, and the foam 60 is fed while being rotated in the direction of the arrow b, so that the processing allowance is obtained. The part 61 is removed. In the sound absorbing material body 34 thus obtained, the outer surface 3 forming the surface layer portion is formed.
The porous material of No. 5 exists as it is and does not collapse.

Thereafter, in FIG. 2C, a protective film sheet 40 is attached to the sound absorbing material body 34, and the outer surface 35 of the sound absorbing material body 34 and the vertical surfaces 36 on both sides are covered with the protective film sheet 40. Thus, the porous member 31 having the protective coating sheet 40 is formed.

In FIG. 2D, an adhesive is applied to the mounting surface 37 of the porous member 31 (sound absorbing material main body 34), and the four porous members 31 are attached to the mounting portion 22 of the support member 21.
Paste from the inside sequentially. As described above, the porous sound absorbing material 30 continuous in the circumferential direction is formed so as to face the tip portion of the fan 3.

According to the present embodiment, the following effects can be obtained. (1) In manufacturing the fan shroud 20, particularly when manufacturing the sound absorbing material main body 34 of the porous sound absorbing material 30,
Using the band saw 51, the processing margin portion 61 is removed so that the porosity of the surface of the foam body 60 is not crushed, and the outer surface 35 having a good porosity is obtained. For this reason, the sound absorption characteristics on the outer surface 35 side facing the tip portion of the fan 3 can be improved.

(2) Since such an outer surface 35 is covered with the protective film sheet 40, it is not necessary to melt or harden the surface as in the prior art or to perform chemical treatment with chemicals or the like. Good weather resistance and durability can be obtained.

(3) Since the outer surface 35 does not need to be melt-hardened, complicated settings can be made unnecessary, so that the porous sound absorbing material 30 can be easily manufactured.

(4) The protective film sheet 40 is the sound absorbing material body 3
Before attaching the sound absorbing material 4 to the support member 21,
, The protective film sheet 40 can be attached in a state where the sound absorbing material body 34 is handled well, and the attaching operation can be performed efficiently. Further, the vertical surface 36 of the sound absorbing material main body 34, which is hidden by the rising pieces 24 of the support member 21, can be surely covered with the protective film sheet 40, and the workability can be improved in this respect.

(5) Since the mounting portion 22 of the support member 21 is cylindrical, the porous member 31 may be mounted on the flat inner peripheral surface of the mounting portion 22, and the mounting operation can be facilitated.

(6) The mounting portion 22 is formed in a simple cylindrical shape and is easily manufactured using a band-shaped metal plate or the like. It is not necessary to form the supporting member 21 and the fan shroud 20 by a complicated process such as rolling of a metal member.

(7) The protective film sheet 40 is formed of the sound absorbing material main body 3.
4 is stuck not only on the outer surface 35 but also on both vertical surfaces 36, so that the edge along the longitudinal direction of the protective coating sheet 40 which is easy to peel off can be surely secured by the rising piece 24 of the support member 21. Can be covered. Therefore, it is possible to prevent the dust or rainwater from hitting the edge, and it is difficult to peel off the protective film sheet 40, so that the durability and weather resistance of the porous sound absorbing material 30 can be further improved.

(8) Further, by covering each vertical surface 36 of the porous member 31 with the rising piece 24 of the support member 21, the corners formed by the vertical surface 36 and the mounting surface 37 are also covered with dust, rainwater, etc. Good protection. For this reason, there is no fear that the porous sound absorbing material 30 is peeled off from the mounting portion 22 due to dust or rainwater or the like hitting the corners.
Durability and weather resistance can be improved.

(9) Since the inner surface of the fan shroud 20 is formed in a bell mouth shape, cooling air can flow smoothly between the front end side of the fan 3 and the porous sound absorbing material 30, which is generated. The airflow noise can be greatly reduced, and the sound absorption performance can be significantly improved.

It should be noted that the present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.

First Modification: FIG. 3 shows a modification for processing the foam 60 to obtain the sound absorbing material main body 34. In the above-described embodiment, the band saw 51 is used to remove the processing margin portion 61 of the foam body 60. In this modification, a rotatable disk-shaped grinder 52 is used.

In such a case, the grinder 52 rotating in the direction of the arrow c is placed on the removal surface of the machining allowance 61 (FIG. 2).
The foam 60 is sent in a reciprocating manner in the direction of the arrow b according to the shape of the outer surface 35 of the sound absorbing material main body 34 shown in FIG. The foam 60 is fed in the direction of arrow d during the reciprocating feed. Then, these feeds are repeated to grind and remove the entire machining margin portion 61.

However, when there is a feed mechanism on the side of the grinder 52, the machining margin 61 may be removed by moving the grinder 52 side. Further, the grinder is not limited to a disc-shaped one, and a cylindrical grinder that rotates on an axis along the longitudinal direction of the foam body 60 may be used.
In addition, the diameter and the like of the grinder may be arbitrarily determined in the implementation.

Second Modification: FIG. 4 shows a technique for removing a processing margin portion 61 of a foam 60 using a heating wire 53 such as a nichrome wire. In this modification, the shape of the heating wire 53 is curved in advance to the shape of the removal surface of the machining allowance portion 61, and the foam 60 is pointed to the heating wire 53 by an arrow d (or an arrow is applied to the foam 60). By sending the hot wire 53 in the direction opposite to the arrow d), the processing margin portion 61 can be blown and removed.

Third Modification: FIG. 5 shows a modification relating to the structure of covering the sound absorbing material main body 34 with the protective coating sheet 40. In this modification, the entire surface of the sound absorbing material main body 34, that is, the outer surface 35, both vertical surfaces 36, and the mounting surface 37 are all covered with the protective film sheet 40.
Such a structure is, for example, the mounting portion 22 of the support member 21.
This is effective when a plurality of through holes are formed in (FIG. 1) and noise energy is expected to be attenuated by these through holes.
The mounting surface 37 of the sound absorbing material main body 34 can be effectively protected from rainwater or the like entering through the through hole.

Fourth Modification: FIG. 6 shows the protective coating sheet 4
Another variant of the covering structure using 0 is shown. In this modification, only the outer surface 35 of the sound absorbing material body 34 is covered with the protective film sheet 40. Even in such a case, the porous sound absorbing material 30 can be provided with sufficient weather resistance and durability, and can be protected. By using the film sheet 40 with a minimum necessary size, material costs can be reduced.

Even in such a case, the edge of the protective coating sheet 40 is slightly enlarged and extended so as to reach each vertical plane 36 (see a two-dot chain line). It is desirable to cover with the upper piece 24. This makes it difficult for the protective film sheet 40 to peel off, and as described in the effect (7) of the embodiment, the porous sound absorbing material 3
0, the weather resistance and durability are further improved.

Fifth Modification: FIG. 7 shows a modification of the cross-sectional shape of the sound absorbing material main body 34. The sixth to tenth modifications shown in FIGS. 8 to 12 are also modifications of the cross-sectional shape of the sound absorbing material main body 34. In the modification shown in FIG. 7, the radius R ₂ of the outer surface 35 at the downstream opening 33 is larger than the radius R ₂ of the upstream opening 32.
Larger than the radius R ₁ of the outer surface 35 at, towards the downstream side opening 33 is gradually widened than the upstream side.

Sixth Modification: In the sound absorbing material body 34 shown in FIG. 8, a bell mouth-shaped upstream opening 32 and a downstream opening 3 are formed.
3 is substantially different from the other sound absorbing material main bodies 34 in that a straight line portion 38 is provided. Also, in this modified example,
Like the fifth modification, the radius R ₂ of the downstream opening portion 33 is larger than the radius R ₁ of the upstream opening portion 33.

Seventh Modification: In the sound absorbing material main body 34 shown in FIG. 9, the bell mouth-shaped portions of the outer surface 35 of the upstream opening 32 and the downstream opening 33 are formed not as curved surfaces but as straight lines. This point is significantly different from the other sound absorbing material main bodies 34.
Further, in this modified example, as in the sixth modified example, a linear portion 38 is provided between the upstream opening 32 and the downstream opening 33. However, the straight portion 38 and the openings 32, 33
The outer surface 35 has a curved surface in consideration of the smooth flow of the cooling air.

Eighth Modification: The sound absorbing material main body 34 shown in FIG.
Is a shape adopting the downstream side from the approximate center of the sound absorbing material main body 34 of the embodiment, and has only the downstream side opening 33 opened in a bell mouth shape. Further, the rising piece 24 on the upstream side of the support member 21 is provided to be longer than the rising piece 24 on the downstream side corresponding to the shape of the sound absorbing material main body 34, and the rising piece 24 on the upstream side is provided. Has reached the outer surface 35 of the sound-absorbing material main body 34 and almost the surface position. This allows
The wind pressure directly acts on the vertical surface 36 on the upstream side, which is a large area, and prevents dust and the like from colliding vigorously,
Improves durability.

Ninth Modification: Sound Absorbing Material Main Body 34 shown in FIG.
Is a shape using substantially the downstream half of the sound absorbing material main body 34 of the sixth modified example in FIG. 8, and has a bell mouth-shaped downstream opening 3.
3 and the straight portion 38 on the upstream side. The shape of the support member 21 is the same as that of the eighth modification.

Tenth modification: sound absorbing material main body 3 shown in FIG.
Reference numeral 4 denotes a shape using substantially the downstream half of the sound absorbing material main body 34 of the seventh modified example in FIG. 9, and includes a bell mouth-shaped downstream opening 33 formed of a straight line, and a straight line portion 38 on the upstream side. It is composed of The shape of the support member 21 is the same as in the eighth and ninth modifications.

Other Modifications In the above embodiment, the porous sound absorbing material 30 is constituted by a plurality of porous members 31.
One continuous porous sound absorbing material 30 may be used.

In the above embodiment, the linear porous member 31 is attached to the mounting portion 22 of the support member 21. However, for example, the heating is performed so that the porous state of the surface of the porous member 31 does not change. By doing so, the porous member 31 may be curved in advance so as to match the inner peripheral surface of the mounting portion 22, so that the porous member 31 may be more easily attached.

In the above embodiment, after the protective film sheet 40 is attached to the sound absorbing material main body 34 to complete the porous member 31, the porous member 31 is attached to the mounting portion 2 of the support member 21.
2, but the sound absorbing material body 34 is first attached to the mounting portion 2.
2 and the protective film sheet 40 may be attached later. However, considering the ease of handling when attaching the protective film sheet 40 to the sound absorbing material main body 34, it is desirable to adopt the above-described embodiment.

In addition, the cross-sectional shape of the support member 21, the cross-sectional shape and material of the sound-absorbing material main body 34, the material of the protective film sheet 40, and the like are not limited to those described in the above-described embodiments or the respective modified examples. In this case, it can be arbitrarily changed. Further, in order to obtain the sound absorbing material main body 34, it is sufficient that the porosity of the surface is not crushed, and other arbitrary devices and tools can be used in addition to the band saw 51, the grinder 52, and the heating wire 53 described above. .

The fan shroud manufactured by the manufacturing method of the present invention is not limited to an engine cooling system of a power shovel, but also to an engine cooling system of a special vehicle including other construction machines, a general passenger car, and various factories. ,
The present invention can be used for an industrial cooling system typified by a cooling water tower for cooling plant cooling water. That is, the fans include those driven by a motor in addition to those driven by an engine.

[0054]

[Brief description of the drawings]

FIG. 1 is an enlarged view showing a main part of an example in which a fan shroud manufactured by a manufacturing method according to an embodiment of the present invention is applied to an engine cooling system.

FIG. 2 is a schematic diagram for explaining a manufacturing method of the embodiment.

FIG. 3 is a perspective view showing a first modification of the present invention.

FIG. 4 is a perspective view showing a second modification of the present invention.

FIG. 5 is a sectional view showing a third modification of the present invention.

FIG. 6 is a sectional view showing a fourth modification of the present invention.

FIG. 7 is a sectional view showing a fifth modification of the present invention.

FIG. 8 is a sectional view showing a sixth modification of the present invention.

FIG. 9 is a sectional view showing a seventh modification of the present invention.

FIG. 10 is a sectional view showing an eighth modification of the present invention.

FIG. 11 is a sectional view showing a ninth modification of the present invention.

FIG. 12 is a sectional view showing a tenth modification of the present invention.

[Explanation of symbols]

 Reference Signs List 3 fan 20 fan shroud 21 support member 22 mounting portion 30 porous sound-absorbing material 34 sound-absorbing material main body 40 protective film sheet as protective film 60 foam

Claims (4)

[Claims] 1. A method for manufacturing a fan shroud (20) using a porous sound absorbing material (30) disposed opposite to a tip end side of a rotationally driven fan (3), comprising: At least the fan (3) of the body (60)
The surface (35) facing the tip end side of the fan shroud (20) without crushing the porosity near the surface layer of the surface (35).
A processing step of obtaining a sound absorbing material main body (34) by processing into an inner shape of the fan; and a tip portion of at least the fan (3) among the sound absorbing material main body (34) processed into an inner shape of the fan shroud (20). The surface facing the side (35) is covered with a protective film (4
0), and attaching the sound absorbing material body (34) processed into the inner shape of the fan shroud (20) to the mounting portion (2) of the support member (21).
2) A method of manufacturing a fan shroud using a porous sound-absorbing material, comprising: 2. A porous sound-absorbing material according to claim 1.
A method of manufacturing a fan shroud (20) using a sound absorbing material main body (34), wherein a surface of the sound absorbing material main body (34) facing a tip end side of the fan (3) is covered with a protective film (40), A method for manufacturing a fan shroud using a porous sound-absorbing material, wherein (34) is attached to an attachment portion (22) of the support member (21). 3. The method of manufacturing a fan shroud (20) using a porous sound absorbing material (30) according to claim 1 or 2, wherein the supporting member (2) to which a sound absorbing material main body (34) is attached.
A method for manufacturing a fan shroud using a porous sound-absorbing material, wherein the mounting portion (22) of 1) is formed in a cylindrical shape. 4. The method for manufacturing a fan shroud (20) using the porous sound absorbing material (30) according to claim 1, wherein an inner surface shape of the fan shroud (20) is a bellmouth. A method for manufacturing a fan shroud using a porous sound-absorbing material.