JPH0331138B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vibration damping cover for an internal combustion engine, and the present invention relates to a vibration damping cover for an internal combustion engine, which is applied to a part or the entire surface of one or both sides of a molded product formed using a polymeric material or a fiber reinforced polymeric material with a bending modulus of 10,000 to 100,000 kg/ ^cm2 . Watatsute unsaturated polyester resin or vinyl ester resin
A molded sheet made by curing an unsaturated polyester resin composition or a vinyl ester resin composition containing 30 to 100 parts by weight of scale-like graphite per 100 parts by weight is bonded with a synthetic resin adhesive. , by laminating and integrating, or by coating and integrating the unsaturated polyester resin composition or vinyl ester resin composition containing the scale-like graphite by spray painting etc. to impart vibration damping properties. It is a composition. Covers for internal combustion engines that are the subject of the present invention, such as timing belt covers, chain covers, timing gear cases, rocker covers, etc., are made of thermoplastic resin or thermosetting resin, in addition to metal, for light weight, corrosion resistance, and ease of processing. It is manufactured and used by molding a so-called polymer material. However, the bending modulus of internal combustion engine covers made of these polymeric materials is very small compared to covers made of metal materials, with a bending modulus of 10,000~
It has a low bending modulus of 100,000 kg/cm ² , which is approximately 1/20 or less of a bending modulus of metal materials, so it is likely to resonate strongly with vibrations transmitted from internal combustion engines and their drive parts, producing unpleasant noises. . The sound caused by the vibration of metal products is generally 1000 to 4000
Hz, whereas internal combustion engines using polymer materials exhibit high resonance peaks in the relatively low frequency range of 500 to 1,500 Hz, which lowers the overall noise level of equipment such as automobiles. This is one of the major factors contributing to the increase in The inventors of the present invention have conducted intensive research to eliminate the unpleasant noise caused by the covers of internal combustion engines, and have found that, as mentioned above, the unpleasant noise is caused by a high resonance peak in a relatively low frequency range. A layer of an unsaturated polyester resin composition or a vinyl ester resin composition containing scale-like graphite, which is also a polymeric material, is applied to internal combustion engine covers that use the polymeric material that causes the problem as a base material. Through adhesive lamination, we succeeded in successfully eliminating noise and completed the present invention. Covers made of polymer materials for internal combustion engines include polyamide resins such as nylon, nylon 6, nylon 66, and nylon 11, polypropylene resins, ethylene butadiene resins, acrylonitrile resins, polyether resins, vinyl chloride resins, vinyl acetate resins, polyphenylene resins, Synthetic resins such as polyester resins, epoxy resins, and phenolic resins are used alone or compositions reinforced with glass fibers, etc., and bending modulus is also used as covers for internal combustion engines.
It is necessary to have 10000 to 100000Kg/ ^cm2 . If their bending modulus is lower than 10,000 kg/cm ² , they are not durable in terms of structure and strength, and if a large amount of reinforcing material such as glass fiber is added to increase the rigidity,
If the bending modulus exceeds 100,000 Kg/cm ² , covers for internal combustion engines become brittle and difficult to use, making them unsuitable for use as covers for internal combustion engines. The vibration damping cover for an internal combustion engine of the present invention is made of unsaturated polyester resin or vinyl ester resin on a part or the entire surface or back surface of the above-mentioned internal combustion engine covers.
A sheet produced by molding an unsaturated polyester resin composition or vinyl ester resin composition containing 30 to 100 parts by weight of scale-like graphite per 100 parts by weight using, for example, peroxide as a curing agent ( (hereinafter referred to as molded sheets) using a synthetic resin adhesive by leaving them at room temperature or by heating to harden them, bond them together, and laminate them to integrate them, or alternatively, instead of laminating molded sheets, you can use the above scale-like graph. Although it is possible to spray or brush a coating material of an unsaturated polyester resin composition or a vinyl ester resin composition containing Aite, it is also possible to apply the coating by adhesively laminating the molded sheets using an adhesive. Compared to the case where the adhesive is applied by spraying or the like, there is a large amount of paint loss, but it has the advantage of being easier to apply in the case of a complex shape with many irregularities. As the base material composition of the molded sheet, unsaturated polyester resins or vinyl ester resins such as bisphenol-based, isophthalic acid-based, terephthalic acid-based, and helical acid-based resins are suitable. There is no particular limit to the particle size of the scale-like graphite, but if vibration damping properties and formability are taken into consideration, it is 50 to 300.
Micron particle sizes are preferred. On the other hand, synthetic resin adhesives such as polyurethane-based, epoxy-based, cyanoacrylate-based, and acrylic-based adhesives are preferred from the viewpoint of adhesive strength. Furthermore, in the case of a molded sheet, the scaly graphite mixed in is regularly arranged horizontally and superimposed within the molded sheet, and after hardening, moisture infiltrates from the outside and deterioration accelerating substances such as NO _x , SO _x and Since it blocks salts, it also has the advantage of helping to prevent deterioration of the polymer material base material. When applying a coating material made of a synthetic resin composition, the horizontal arrangement of scale-like graphite within the coating film tends to be slightly disturbed, but this has almost no effect on anticorrosion performance. In the case of internal combustion engines in automobiles, the surrounding atmosphere often comes into contact with _NOx , _SOx , salt water, water, oil, etc. in the exhaust gas, and this accelerates the deterioration of the covers. In the case of folding covers, the inertness and heat resistance characteristics of flaky graphite are exhibited by the use of molded sheets or, to a lesser extent, multiple coatings of coating materials, which prevent deterioration of the covers. significantly contributes to Next, the present invention will be explained with reference to the drawings. FIG. 1 shows a partial cross-sectional view of an embodiment of a damping cover for an internal combustion engine according to the present invention, in which the surface of a polymeric material portion 1 made of thermoplastic resin or thermosetting resin is coated with unsaturated polyester resin or vinyl. A molded sheet 3 made of a cured unsaturated polyester resin composition or a vinyl ester resin composition containing 30 to 100 parts by weight of scale-like graphite per 100 parts by weight of the ester resin is bonded using a synthetic resin adhesive 2. It shows a laminated and integrated structure, and 4 is scale-like graphite that is horizontally superimposed and oriented. The amount of scaly graphite is based on 100 parts by weight of unsaturated polyester resin or vinyl ester resin.
If the amount is less than 30 parts by weight, the damping effect will be low, and if the amount exceeds 100 parts by weight, the strength of the formed sheet will be low. Regarding the thickness ratio between the thickness of the molded sheet and the thickness of the polymeric material part that makes up the covers, if the thickness ratio is less than 0.5, the damping effect will be low, and the loss coefficient will be smaller than the conventionally required loss coefficient of 0.05. On the other hand, if the thickness ratio exceeds 3.0, the rate of increase in the damping effect indicated by the loss coefficient will be slow, which is rather unfavorable from the point of view of economy and weight increase. This also applies to damping covers manufactured by spray painting unsaturated polyester resin or vinyl ester resin. Here, the loss coefficient (Ycomb.) is expressed as Ycomb.≒〓/π, where 〓 is the logarithmic attenuation rate and 〓 is the pi ratio. [According to the Noise Countermeasures Handbook (1971 edition, p. 433), edited by the Japan Acoustic Materials Association. ] Figure 2 shows the content of glass fiber reinforced polypropylene [alkali-free short glass fibers (diameter 10μ, length approx. 0.5mm)
30 parts by weight] base material (length, 250 x width,
30 parts by weight of scale-like graphite (particle size 150 μ), 0.6 parts by weight of cobalt naphthenate, and 1 part by weight of MEKPO per 100 parts by weight of bisphenolic unsaturated polyester resin (10×thickness, 1 mm). A molded sheet (length 250 mm) cured with the mixed composition
x width 10 x thickness 1 mm) using an epoxy resin adhesive (Cemedine No. 1500 manufactured by Cemedine Co., Ltd.) was used, and after curing at room temperature, the loss factor was determined using the cantilever damping method. Curve 5 in FIG. 2 shows the relationship between the formed sheet and the loss factor when the thickness of the formed sheet was changed from 0.5 mm to 5.0 mm. Here, the thickness ratio (h) was determined as h=thickness of molded sheet (mm)/thickness of base material (mm). Meanwhile, steel plate (SPC) base material (length, 250 x width, 10 x
The above molded sheet and epoxy resin adhesive (using Cemedine No. 1500 manufactured by Cemedine Co., Ltd.) were adhered to the surface layer on one side of the film (thickness: 1 mm), and after curing at room temperature, the cantilever damping method was applied in the same manner. The loss coefficient was determined by , and the relationship between the thickness ratio (h) of the molded sheet and the loss coefficient (Ycomb.) is shown in Figure 3. As can be seen from Figures 2 and 3, glass fiber reinforced polypropylene molded products (bending modulus
23,000Kg/cm ² ) has a relatively higher loss coefficient than a molded product using a steel plate (bending modulus of 2,000,000Kg (cm ² )), and it has been found that the damping effect is particularly large at a small thickness ratio (h). From these results, in the case of the present invention, covers made of polymeric materials are expected to have a damping effect even if the thickness of the molded sheet is thin.Example 1 Short glass fibers (about 20μ in diameter) After pre-degreasing a part of the surface of a timing gear case (thickness 3.0 mm) made from a nylon resin base material containing 30 parts by weight of vinyl ester resin (10 mm in length), 30 parts by weight for 100 parts by weight of vinyl ester resin. A sheet (thickness 2.0 mm) obtained by curing and molding the vinyl ester resin composition mixed with scale-like graphite (particle size 50 μm) was coated with an acrylic adhesive (Toughlock No. 6201 manufactured by Sunstar Giken Co., Ltd.).
(used) and integrated them by adhesion and lamination. This timing gear case was attached to an internal combustion engine and the degree of noise attenuation was measured. The results are shown in Table 1.

[Table] From the results in Table 1, the present invention has a frequency of 125 to 1500Hz.
It was confirmed that the sound reduction effect is significant even in the low frequency range such as . The present invention is effectively useful as a countermeasure against noise pollution, which has recently become an urgent problem, and greatly contributes to preserving the living environment by reducing noise and improving the comfort of riding in automobiles, etc.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of one embodiment of a damping cover for an internal combustion engine of the present invention, and Fig. 2 shows the base material thickness of the integrally molded sheet of the present invention when the base material is glass fiber reinforced polypropylene resin. Figure 3 shows the relationship between the thickness ratio of the coating layer and the loss coefficient, and Figure 3 shows the relationship between the thickness ratio of the base material thickness and the coating layer and the loss coefficient of an integrally formed sheet using a steel plate as the base material and manufactured in the same manner. It is a figure showing a relationship. 1...Base material part of polymer material of covers, 2...
...Adhesive layer, 3... Molded sheet portion, 4... Scale-like graphite oriented in a horizontally overlapping manner within the molded sheet, 5, 6... Curve showing the relationship between loss coefficient and thickness ratio.

Claims (1)

[Claims] 1. When adhesively laminating a polymer material or fiber-reinforced polymer material with a bending modulus of 10,000 to 100,000 Kg/cm ² on one or both sides of the molded product 1, partially or completely on one or both sides of the molded product 1. , unsaturated polyester resin or vinyl ester resin
A molded sheet prepared by curing an unsaturated polyester resin composition or vinyl ester resin composition 3 containing 30 to 100 parts by weight of scale-like graphite 4 per 100 parts by weight is used as a synthetic resin adhesive 2. Therefore, the unsaturated polyester resin composition or vinyl ester resin composition 3 containing the scale-like graphite 4 is coated by spraying or the like, and then the unsaturated polyester resin composition or the vinyl ester resin composition 3 itself is coated and integrated. A vibration damping cover for internal combustion engines featuring: