JPH11132102A - Engine cover and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine cover which is lightweight and is excellent in corrosion resistance and sound insulating performance by filling a soundproof material in a cavity formed inside a surface layer material. SOLUTION: When an engine cover is manufactured, a reinforced nylon 6 resin is put and melted in a cylinder 6 as resin to form a surface layer material. A pellet of a foaming resin composed of a urethane resin and azodicarbonamide is put, melted and foamed in a cylinder 7 as resin to form a soundproof material. The reinforced nylon 6 resin melted by the cylinder 6 is injected into a die 9 through a spool 8, and the foaming resin melted by the cylinder 7 is injected inside the reinforced nylon 6 resin previously injected through the same spool 8, and is integrally formed. The reinforced nylon 6 resin is injected from the cylinder 6 to cover an injection tail end part of the foaming resin, and the injection tail end part of the foaming resin is covered. Therefore, an engine cover which is lightweight and is excellent in corrosion resistance and sound insulating performance, can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine cover which is lightweight, has excellent corrosion resistance and sound insulation, and can be mass-produced even in a complicated shape, and a method for manufacturing the same.

In particular, the present invention is suitable as an engine cover for preventing leakage of noise generated in an engine room of an automobile such as a passenger car or a large commercial vehicle (truck), or an engine room of a ship such as a motor boat or a passenger ship. The present invention relates to an engine cover that can be used for a vehicle and a method for manufacturing the same.

[0003]

2. Description of the Related Art Noise generated in the engine room of automobiles such as passenger cars and heavy commercial vehicles and in the engine room of ships such as motorboats and passenger ships reduces fatigue and improves comfort for drivers and occupants. From the viewpoint of preventing noise to the surroundings, reduction of the noise is required.

[0004] Therefore, an engine cover is provided around the engine. Such an engine cover is, for example, a glass wool or polyester nonwoven fabric on the inner surface of an engine cover made of a metal plate such as a steel plate or an aluminum alloy. And a metal engine cover provided with a side cover made of a rubber plate as a mounting member.

[0005] However, the metal engine cover has a problem that it has low sound insulation and is heavy. Also, with metal engine covers with side covers made of rubber plates used for cab-over type trucks, a space is created between the side covers and the engine cover, causing noise and splashing while driving. There was a problem that it easily entered into the engine room.

Accordingly, Japanese Patent Application Laid-Open No. Hei 8-40154 discloses that
As an engine cover that does not require a side cover, it consists of a back plate made of a steel plate attached to the body frame, a polymer foam bonded to one surface of the back plate, and a polyurethane film covering the surface of the polymer foam. There has been proposed an engine cover in which a surface material is integrally formed. However, since the engine cover is provided with a back plate made of a steel plate, the engine cover is heavy and easily rusts similarly to the engine cover made of the steel plate, and sufficient sound insulation cannot be obtained.

Further, Japanese Patent Application Laid-Open No. 3-206324 proposes that the body of the engine cover is formed of a plastic resin in order to reduce the weight of the engine cover. Specifically, the engine cover and the side cover are formed of a thermoplastic resin containing a long fiber reinforcement of 5 mm or more, and are lightweight and excellent in corrosion resistance and sound insulation. However, since the engine cover is formed by stamp molding, there is a problem that it is difficult to obtain a complicated shape.

For the purpose of manufacturing a complicated shape, it has been proposed to manufacture an engine cover by injection molding using a polyamide resin such as nylon 6, and some of them have been put to practical use. However, this engine cover also did not have sufficient sound insulation. Also, Japanese Patent Application Laid-Open No.
No. 5 proposes a heat-resistant synthetic resin substrate in which at least one of an outer surface and an inner surface is directly roughened and a sprayed metal foil is formed on the roughened surface. . However, the engine cover according to this method cannot be said to have sufficient sound insulation, and is inferior in mass productivity.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides an engine cover which is lightweight, has excellent corrosion resistance and sound insulation, and can be mass-produced even with a complicated shape, and a method of manufacturing the same. Is what you do.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the gist of the present invention is an engine cover in which a sound insulating material is filled in a cavity formed inside a surface material.

According to the present invention, since the soundproofing material is filled in the cavity formed inside the surface material, it is possible to provide an engine cover that is lightweight and has excellent corrosion resistance and sound insulation.

Further, the method of manufacturing an engine cover according to the present invention is characterized in that the soundproof material is filled inside the surface material by forming the surface material and the soundproof material by a sandwich molding method. According to this manufacturing method, unlike the conventional stamp forming method, mass production is possible even with a complicated shape.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The engine cover of the present invention has a surface material and a soundproof material formed in three layers, and it is necessary to fill the soundproof material into a cavity formed inside the surface material. is there.

The surface layer material is preferably formed of a resin or a reinforced resin having a heat deformation temperature of 100 ° C. or more and a flexural modulus of 1000 MPa or more. Heat deformation temperature is 100
When the temperature is lower than ℃, it is difficult to obtain an engine cover having excellent heat resistance, and when the flexural modulus is lower than 1000 MPa, it is difficult to obtain an engine cover having excellent rigidity.

As such a surface layer material, a reinforced polyamide resin in which a layered silicate is uniformly dispersed at a molecular level can be suitably used. When the layered silicate is uniformly dispersed at the molecular level in the polyamide resin, one layer of the layered silicate layer,
Or, a state in which 50% or more, and preferably 70% or more, of the multi-layered material having an average overlap of 5 layers or less is parallel or random, or a mixture of parallel and random, without forming a lump. Say. For example, when the swellable fluoromica-based mineral as a layered silicate is uniformly dispersed at the molecular level, when a wide-angle X-ray diffraction measurement is performed on the resin pellet, the silicate layer of the swellable fluoromica-based mineral is determined. The peak due to the thickness direction disappears. Therefore,
By this measurement, the dispersion state of the swellable fluoromica-based mineral can be confirmed.

Since the layered silicate is uniformly dispersed at the molecular level in the polyamide resin as described above, the reinforced polyamide is excellent in rigidity such as flexural strength and flexural modulus, impact resistance and heat resistance, and is lightweight. Since it is made of resin, it can be suitably used as an engine cover. In general, the higher the elastic modulus, the lower the transmitted sound. Therefore, the use of the reinforced polyamide resin improves the sound insulation. The mixing ratio of the layered silicate to the polyamide resin is not particularly limited, but is preferably 0.1 to 10% by weight. When the compounding ratio of the layered silicate is less than 0.1% by weight, mechanical properties such as flexural strength and flexural modulus and heat resistance are inferior. The layered silicate is 1
If it exceeds 0% by weight, injection molding into a molded article becomes difficult.

In addition to the reinforced polyamide resin in which the layered silicate is uniformly dispersed at the molecular level, other resins that can be used as a surface material include polyamide resins such as nylon 6, nylon 66, and nylon 12, and the above-mentioned polyamide resins. Reinforced polyamide resin reinforced with glass fiber or carbon fiber, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, reinforced polyester resin reinforced with the above polyester resin with glass fiber or carbon fiber, polycarbonate resin, polyarylate resin A reinforced polyolefin resin obtained by reinforcing a polyolefin resin such as polypropylene, polymethylpentene, or the like with glass fibers or carbon fibers can be suitably used.

Further, in the present invention, as a surface layer material, polyacetal resin, ABS resin, polyphenylene ether,
Modified polyphenylene ether, polysulfone, polyphenylene sulfide, polyether ketone, liquid crystal polyester and the like can also be used.

The soundproofing material to be filled into the surface layer material is made of a resin foam, and the pellets forming the resin foam are prepared by mixing a resin and a foaming material in an arbitrary mixing ratio with a Banbury mixer or a pressurized seeder. It is formed by kneading with a temperature such that the softening point of the resin exceeds the softening point by several degrees and using a biaxial roll, and does not cause decomposition of the foamed material, and then cooling and pulverizing. Then, the resin pellets are heated and melted while decomposing the foam material, and injection molding or the like is performed to form a resin foam. The mixing ratio of the foaming material is
It can be arbitrarily set according to the expansion ratio of the intended foamed material.
About 0 part by weight is blended. If the compounding ratio of the foaming material is less than 1 part by weight, the sound insulating property becomes poor due to insufficient foaming ratio, and if the compounding ratio exceeds 20 parts by weight, the foam becomes uneven and the sound insulating property becomes poor.

Examples of the resin constituting the resin foam include urethane resin, styrene-butadiene rubber, ethylene-propylene-diene rubber, nitrile-butadiene rubber, chloroprene rubber, isoprene rubber, isobutylene-isoprene rubber, silicone rubber, ethylene-acrylic A rubber-based resin such as rubber, a polyolefin-based resin such as polypropylene or an ethylene-propylene polymer, or polyethylene can be suitably used. As the foam material, an inorganic or organic foam material can be used without particular limitation. Specifically, sodium bicarbonate, ammonium bicarbonate, ammonium chloride, sodium carbonate, ammonium carbonate, azodicarbosamide, dinitrosopentamethylenetetramine, dinitrosoterephthalamide, azobisisobutyronitrile, sulfonyl hydrazides, and the like. No.

In addition, a small amount of commonly used foaming aids such as urea and its derivatives and metal oxides can be used in combination with the above foaming material. Further, a plasticizer, a cross-linking agent, a cross-linking accelerator, a vulcanizing agent, a vulcanization accelerating agent, a filler, and the like may be added to the resin foam composed of the resin and the foaming material as necessary.

The engine cover of the present invention is manufactured using a sandwich molding machine, which is a kind of conventionally known injection molding machine. FIG. 4 and FIG. 5 schematically show the configuration of a general sandwich molding method and the manufacturing process of an engine cover using the sandwich molding method. As shown in FIG. 4, different materials are melted in the cylinder 6 and the cylinder 7, respectively.
a is filled into the die 9 through the same sprue 8. Specifically, a resin 4a as a material of a surface layer material is melted in the cylinder 6, and a foamed resin 5a as a material of a soundproofing material is melted in the cylinder 7. And FIG.
As shown in (a), first, a molten resin 4a, which is a material of a surface layer material, is supplied from a cylinder 6 through a sprue 8 to a die 9a.
It is injected inside. Thereafter, as shown in FIG. 5B, the foamed resin 5a in a molten state is injected from the cylinder 7 into the resin 4a injected into the die 9 via the sprue 8. Then, as shown in FIG. 5C, a small amount of the resin 4a melted again from the cylinder 6 is injected into the die 9 through the sprue 8, and covers the injection end portion of the foamed resin 5a.

At this time, the melting temperature of the resin 4a is set to a temperature 10 to 50 ° C. higher than its softening point, and the melting temperature of the foamed resin 5a is a temperature at which the foamed material is decomposed and foamed, usually 200 times.
C. to 250.degree. C.

[0024]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the measurement of various physical property values in the following Examples and Comparative Examples was performed by the following methods.

(1) Dispersibility of the layered silicate: The dispersibility of the layered silicate in the resin pellet was measured by a wide-angle X-ray diffractometer (manufactured by Rigaku Corporation, model number RAD-rB).

(2) Relative viscosity of reinforced polyamide resin and non-reinforced polyamide resin: Dry pellets of each resin were dissolved in 96% by weight concentrated sulfuric acid to a concentration of 1 g / dl and measured at a temperature of 25 ° C. .

(3) Heat deformation temperature (° C.): ASTM-D-
648 using a test piece according to the method described in 648.
It was measured under the conditions of 45 MPa.

(4) Flexural modulus (MPa): ASTM-
According to the method described in D-790, the measurement was performed using a test piece in an absolutely dry state in an atmosphere of 23 ° C. × 50% RH.

(5) Soundproofing effect: As shown in FIG.
0cm, width 30cm, height 8cm, top plate thickness 4m
m, box-shaped engine covers of the examples and the comparative examples each having a side wall thickness of 3 mm and an open lower end were prepared. And
A bench test was performed by attaching each engine cover to the engine under the same conditions, and a microphone was installed at a position 100 cm away from the engine cover to measure the sound pressure level. The temperature of the engine cover at the time of the measurement was 100 ° C. The degree of reduction in the sound pressure level of each engine cover based on the sound pressure level of the conventional engine cover manufactured in Comparative Example 1 was used as an index of the soundproofing effect.

Example 1 First, a swellable fluoromica-based mineral was synthesized. Average particle size is 2μm by ball mill
Sodium silicate having the same average particle size of 2 μm was mixed with talc pulverized so as to be 20% by weight of the total amount, and the mixture was placed in a magnetic crucible.
The mixture was kept at 0 ° C. for 1 hour to synthesize a fluoromica-based mineral.

The resulting fluoromica-based mineral powder was subjected to wide-angle X-ray diffraction measurement (using a RAD-rB type wide-angle X-ray diffractometer manufactured by Rigaku Corporation).
The peak at an axial thickness of 9.2 ° disappeared, and a peak corresponding to 12 to 13 ° indicating the formation of a swellable fluoromica-based mineral was observed.

Next, a reinforced nylon 6 resin was prepared using the swellable fluoromica-based mineral. 1 kg of water and 200 g of swellable fluoromica-based mineral were added to 10 kg of ε-caprolactam which is a raw material of nylon 6 resin, and this was placed in a reaction vessel having a content of 30 liters to polymerize ε-caprolactam. A reinforced nylon 6 resin was obtained. The polymerization reaction was performed as follows.

That is, the raw material mixture was added to 25 while stirring.
Heat to 0 ° C and release 1.5MP
a, then release to normal pressure,
Polymerization was performed at 60 ° C. for 3 hours. When the polymerization was completed, the reinforced nylon 6 resin was discharged from the reaction vessel, and cut into pellets. The pellets were treated with hot water at 95 ° C., refined, and then dried in vacuum.

This reinforced nylon 6 resin has a heat deformation temperature of 193 ° C., a flexural modulus of 4000 MPa, a relative viscosity of 2.5, and contains 2.0% by weight of a swellable fluoromica mineral.
Contained.

The pellets of the reinforced nylon 6 resin were subjected to wide-angle X-ray diffraction measurement. As a result, the peak in the thickness direction of the silicate layer of the swellable fluoromica mineral completely disappeared. It was found that the swellable fluoromica-based mineral was uniformly dispersed therein.

Using the obtained reinforced nylon 6 resin and urethane resin, an injection molding machine (manufactured by Toshiba Machine Co., Ltd., sandwich molding machine IS1300DF-SW) was used to form a top plate having a thickness of 4 mm as shown in FIG. An engine cover 1 having a side wall thickness of 3 mm, a surface layer material thickness of 1 mm, and a soundproofing material thickness of 2 mm was produced. In the engine cover 1, reference numeral 2 denotes a gate forming a spout of the molten material into the cavity, and reference numeral 3 denotes a mounting hole for mounting the engine to the engine.

More specifically, in order to manufacture the engine cover 1, reinforced nylon 6 is used as a resin for forming the surface layer material.
The resin is put into the cylinder 6 shown in FIG.
Melted at 40-250 ° C. As a resin for forming the soundproofing material, a urethane resin (manufactured by Nippon Milactran Co., Ltd., P89
0) A foamable resin pellet composed of 100 parts by weight and 2 parts by weight of azodicarbosamide was placed in a cylinder 7 shown in FIG.
And melted and foamed at a cylinder temperature of 200 ° C. Then, 810 g of reinforced nylon 6 resin melted in the cylinder 6 is first injected into the die 9 through the sprue 8 such that the ratio of the thickness of each layer becomes surface material: sound insulation material: surface material = 1: 2: 1. did. Next, 400 g of the foamed resin melted in the cylinder 7 was injected into the reinforced nylon 6 resin previously injected through the same sprue 8 to be integrally formed. Further, 100 g of reinforced nylon 6 resin was injected from the cylinder 6 to cover the injection terminal of the foamed resin, thereby covering the injection terminal of the foamed resin. The injection pressure was 80 MPa, the injection speed was 100 mm / sec, and the mold temperature was 80 ° C.

As shown in FIGS. 2 (a) and 2 (b), the cross section of the engine cover formed by cooling the injected resin is such that the top plate and the side walls are 2 m thick on a surface material 4 having a thickness of 1 mm.
Thus, a three-layer structure having a total thickness of 4 mm with the m soundproof material 5 interposed therebetween was obtained.

Table 1 shows the measurement results of the characteristics of the obtained engine cover.

[0040]

[Table 1]

Example 2 ε- which is a raw material of nylon 6
To 10 kg of caprolactam, 400 g of the swellable fluoromica-based mineral synthesized by the above method and 1 kg of water were added and placed in a reaction vessel. Otherwise, a resin pellet was produced in the same manner as in Example 1.

The obtained reinforced nylon 6 resin has a heat deformation temperature of 193 ° C., a flexural modulus of 4500 MPa, a relative viscosity of 2.4, and a swellable fluoromica-based mineral of 4.0% by weight as a whole. % By weight. Further, as in Example 1, the swellable fluoromica-based mineral was uniformly dispersed at the molecular level in the nylon 6 resin.

An engine cover was manufactured in the same manner as in Example 1 using the obtained reinforced nylon 6 resin and the urethane resin used in Example 1. Table 1 shows the performance of the engine cover and the like.

(Example 3) As a surface layer material, a heat deformation temperature of 174, which is not strengthened as in Examples 1 and 2, is used.
C., a normal nylon 6 resin having a flexural modulus of 2700 MPa and a relative viscosity of 2.5 (A1030BR manufactured by Unitika Ltd.)
L), and the same urethane resin as in Example 1 was used as the soundproofing material. Other than that, an engine cover was manufactured in the same manner as in Example 1.

Table 1 shows the performance of the engine cover and the like.

Comparative Example 1 Using only the reinforced nylon 6 resin produced in Example 1, an engine cover having dimensions similar to those of Examples 1 to 3 and having the outer shape shown in FIG. 1 was produced. However, the cross section of the engine cover had a single-layer structure as shown in FIG.

In detail, the reinforced nylon 6 resin is supplied by an injection molding machine (made by Toshiba Machine Co., Ltd., sandwich molding machine IS1300).
(DF-SW) and melted at a cylinder temperature of 240 to 250 ° C. Then, the melted reinforced nylon 6 resin 1290
g was injected into the cavity. The injection pressure during injection was 80 MPa, the injection speed was 100 mm / sec, and the mold temperature was 80 ° C.

Table 1 shows the performance of the engine cover and the like.

Comparative Example 2 Nylon 6 having a relative viscosity of 2.5
Only resin (A1030BRL, manufactured by Unitika Ltd.) was used. Other than that, an engine cover was produced in the same manner as in Comparative Example 1.

Table 1 shows the performance of the engine cover and the like.

In each of Examples 1 to 3, the engine cover having a three-layer structure in which the surface material was filled with the soundproofing material was used. A noise reduction effect of 2 to 4 dB was obtained as compared with the cover. In addition, since each was made of a resin engine cover, it was lightweight and excellent in corrosion resistance.

In particular, in Examples 1 and 2, the reinforced polyamide resin in which the layered silicate was uniformly dispersed at the molecular level was used as the surface material, so that the engine cover of Example 3 made of an unreinforced polyamide resin was used. And improved rigidity and heat resistance. In addition, since the rigidity has been improved, the transmitted sound has been reduced, and the soundproofing effect has been slightly improved.

Further, since the engine cover is manufactured by sandwich molding, it is easier than a conventional manufacturing method by stamp molding, and mass production is possible.

[0054]

According to the present invention, an engine cover in which a soundproofing material is filled in a surface layer material can be provided as a lightweight engine cover having excellent corrosion resistance and sound insulation.

Such an engine cover can be suitably used as an engine cover for preventing leakage of noise generated in an engine room of a car such as a passenger car or a large commercial vehicle, or a boat such as a motor boat or a passenger ship.

Further, when such an engine cover is manufactured, by molding the surface layer material and the soundproofing material by a sandwich molding method, it becomes possible to mass-produce even a complicated shape.

[Brief description of the drawings]

FIG. 1 is a perspective view of an engine cover according to an embodiment of the present invention.

FIG. 2 is a view showing a longitudinal section and a transverse section of the engine cover of FIG. 1;

FIG. 3 is a view showing a longitudinal section and a transverse section of an engine cover manufactured in a comparative example.

FIG. 4 is a configuration diagram of a sandwich molding method used for manufacturing the engine cover according to the embodiment of the present invention.

FIG. 5 is a view showing a process of manufacturing an engine cover using the sandwich molding method of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine cover 4 Surface material 5 Soundproof material

Claims (6)

[Claims] 1. An engine cover wherein a soundproofing material is filled in a cavity formed inside a surface material. 2. The engine cover according to claim 1, wherein the surface layer material is formed of a resin or a reinforced resin having a heat deformation temperature of 100 ° C. or more and a flexural modulus of 1000 MPa or more. 3. The engine cover according to claim 1, wherein the surface material is made of a reinforced polyamide resin in which a layered silicate is uniformly dispersed at a molecular level. 4. The surface layer material is a polyamide resin, a reinforced polyamide resin, a polyester resin, a reinforced polyester resin,
3. The engine cover according to claim 1, wherein the engine cover is formed of any one of a polycarbonate resin, a polyarylate resin, and a reinforced polyolefin resin. 5. The engine cover according to claim 1, wherein the soundproofing material is formed of a resin foam material. 6. A method for manufacturing an engine cover, wherein a soundproof material is filled in a surface material by forming a surface material and a soundproof material by a sandwich molding method.