JP3286648B2 - Floating washer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping material provided between a vibrating body and a cover to reduce vibration of a cover (rocker cover, oil pan, etc.) attached to the vibrating body such as an engine. The present invention relates to a floating washer suitable for mounting the cover body by floating the cover body from the vibrating body.

[0002]

2. Description of the Related Art In recent years, engines have tended to have higher horsepower and higher speed, and this tendency has led to an increase in combustion pressure and an increase in heat load. At the same time, in recent years, engines have tended to be lightweight, and this tendency has led to a decrease in the rigidity of the cylinder head and the cylinder block. For this reason, structural deformation due to combustion pressure in the cylinder head and cylinder block increases, and accompanying it, a rocker cover with relatively low rigidity attached to the engine,
Vibrations of the oil pan cover, the heat insulator (heat shield), and the like are also increased, which has been found to be a major factor in generating engine noise. FIG. 1 shows an example of the rocker cover (1 is a rocker cover, 2 is a rocker cover gasket).

In response to the recent tightening of noise regulations for reducing engine noise, various measures against noise in the rocker cover and the like have been studied. As one of the measures, the rocker cover and the like are made of a vibration damping material such as synthetic rubber. It has been found that floating (floating) from the engine main body through the through hole is extremely effective in reducing noise.
As shown in FIG. 5, a floating washer is used together with a gasket for fastening a rocker cover or the like.

FIG. 2 shows a conventional floating washer 3 in which a synthetic rubber molded product 5 such as NBR or acrylic rubber is adhered to a disk-shaped steel plate 4. There are two types of tightening structures for the rocker cover: side bolt tightening and center bolt tightening. FIG. 3 shows an example of the side bolt tightening of the rocker cover, and the bolt 6 inserted into the flange portion 1a of the rocker cover 1 is shown in FIG. Is screwed into the cylinder head 7, and a floating washer 3 is interposed between the head of the bolt 6 and the flange portion 1a of the rocker cover 1. In this case, since the bolt 6 does not penetrate the inside of the rocker cover 1, the washer 3 does not need to have a sealing property.

FIG. 4 shows an example of tightening the center bolt of the rocker cover 1. A bolt 6 inserted into the center of the rocker cover 1 is screwed into a cylinder head 7, and the head of the bolt 6 is connected to the rocker cover 1. A floating washer 3 is interposed between the rocker cover 1 and the locker cover 1 shown in FIG.
Is a bolt for tightening such a center bolt, and a bolt hole 8 is provided at the center. In the case of such center bolt tightening, since the bolt 6 penetrates through the inside of the rocker cover 1, the washer 3 needs a sealing function to prevent oil leakage from inside the rocker cover 1.

[0006]

Conventionally, in both of the side bolt fastening and the center bolt fastening,
Since the floating washer 3 in which the synthetic rubber molded product 5 is bonded to the steel plate 4 is used, the following various drawbacks have occurred.

A) Synthetic rubber (NBR, etc.) generally has a heat resistance of about 150 ° C. and a low heat resistance. On the other hand, since the engine oil temperature and the temperature of the rocker cover 1 are increasingly higher, the synthetic rubber molded product 5 of the washer 3 is easily set, and the torque reduction is increased accordingly. For this reason, in the case of side tightening, oil leakage from the rocker cover gasket 2 is likely to occur as shown by the arrow in FIG. In the case of center tightening, as shown in FIGS. 4 and 5, direct leakage from the washer 3 and oil leakage from the rocker cover gasket 2 are likely to occur.

B) As described above, since the synthetic rubber has low heat resistance, the vibration damping effect and, consequently, the noise reduction effect tend to be reduced as the temperature rises.

C) In general, since the adhesion between synthetic rubber and metal is relatively weak, when the temperature rises and the tightening load increases, the synthetic rubber molded product 5 peels off from the steel plate 4 and synthesizes with the lateral flow of the synthetic rubber. Cracking of the rubber molded product 5 is apt to occur. D) The number of processing steps, such as the production of the steel plate 4, the treatment with an adhesive, and the molding of the synthetic rubber molded product 5, are large, and the cost is high.

The present invention has been made in view of such circumstances, and has a reduced settling even when a thermal load is increased, can reduce torque reduction, and prevents oil leakage from a washer mounting portion and a rocker cover gasket. It is an object of the present invention to provide a floating washer capable of reducing the noise reduction effect, reducing cracking and peeling of the damping material, and reducing the cost.

[0011]

A floating washer according to the present invention is obtained by laminating a plurality of coating plates each formed by coating a metal plate with a compound layer containing compressible fibers, an elastomer and a filler.

As the compressible fiber, a compressible inorganic fiber or a compressible organic fiber may be used alone, or a mixture of both may be used.

Examples of the compressible inorganic fiber include glass fiber, ceramic fiber, rock wool, mineral wool, fused quartz fiber, chemically treated high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, and boron nitride fiber. And alkali titanate fibers, whiskers, boron fibers, carbon fibers, metal fibers, and the like.

Examples of the compressible organic fibers include aromatic polyamide fibers, polyamide fibers, polyolefin fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, and polyurea fibers. And polyurethane-based fibers, polyfluorocarbon-based fibers, phenol fibers, and cellulosic fibers.

As the elastomer, for example, NB
R, styrene butadiene rubber (SBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), butyl rubber (IIR), ethylene-propylene rubber (EPM), fluoro rubber (FPM), silicone rubber (SI) ), Chlorosulfonated polyethylene (C
SM), ethylene vinyl acetate rubber (EVA), polyethylene chloride (CPE), butyl chloride rubber (CIR), shrimp chlorohydrin rubber (ECO), nitrile isoprene rubber (N
IR), natural rubber (NR) and the like, and an oil-extended rubber obtained by adding a naphthenic process oil to a rubber material such as the SBR can also be used.

As the filler, an inorganic filler is preferable, and for example, clay, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoliite, wollastonite and the like can be used.

The amount of the compressible fiber and the filler in the compound is preferably 50% or more (weight). The thickness of the compound layer of the coated plate is 1 for a single-side coated plate
00-400μ, 1 for both sides coating
About 00 to 400 μm is preferable.

[0018]

In the floating washer of the present invention,
Unlike conventional floating washers in which a synthetic rubber molded product is adhered to a steel plate, a structure in which a compound plate containing a compressible fiber, an elastomer, and a filler is coated on a metal plate is laminated as follows. Action is obtained.

A) Since the compound has good heat resistance, even if it is compressed by a tightening load, the compound layer has less lateral flow and less settling. Therefore, the torque holding force is good, and leakage from the washer, the rocker cover gasket, and the like hardly occurs as in the case of the conventional floating washer.

B) As described above, since the compound has good heat resistance, even if the thermal load increases, the decrease in the vibration damping effect is small.

(C) Since the compound has better adhesiveness to the metal plate than the synthetic rubber alone, even if the tightening force is large, the pressure resistance is large, so that the compound layer peels off from the metal plate or cracks in the compound layer. (Cracks) do not occur.

D) The number of processing steps is small, and the manufacturing cost can be reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. Example 1 A compound having the following composition was prepared.

(A) Glass fiber 30% by weight (b) Fibrillated aromatic polyamide fiber 10% by weight (trade name Kepler pulp, manufactured by DuPont) (c) Nitrile rubber (NBR) 16% by weight (d) Rubber chemical 4% by weight (e) Inorganic filler 40% by weight As rubber chemicals, vulcanizing agents such as sulfur, zinc oxide, magnesium oxide, peroxide, dinitroribenzene, and thiazole-based compounds, polyamine-based compounds, sulfonated Vulcanization accelerators such as phenamide-based compounds, dithiocarbamate-based compounds, aldehydeamine-based compounds, guanidine-based compounds, thiourea-based compounds, and xanthate-based compounds can be used.

As shown in FIG. 6, a metal plate 12 made of an aluminum plate coated on one side with a heat-resistant adhesive 11 in advance.
The compound 13 having the above-described composition is coated on the one side (thickness: 0.3 mm) to a thickness of 400 μ to form a coating plate 14, and the surface of the layer of the compound 13 of the coating plate 14 is heat-resistant. Adhesive 1
5 is applied. The thickness of the adhesives 11 and 15 is 1
About 0 ± 5μ is preferable. Next, the coating plate 1
4 as shown in FIG. 7 (in the example shown in FIG.
And a metal plate 16 (thickness 0.3 mm) made of an aluminum plate on the surface of the uppermost coating plate 14 on which the adhesive 15 of the compound 13 has been applied, and heating and pressing Glue.

After bonding, a heat treatment is performed in an atmosphere at a temperature of 140 to 160 ° C. for 40 to 60 minutes to obtain a laminate (thickness: 3.1 mm). Note that the heat treatment is performed using the rubber,
It is carried out in order to accelerate the crosslinking reaction of rubber chemicals and heat-resistant adhesives 11, 15 and the like. Next, a floating washer 17 as shown in FIG. 8 is obtained by punching the laminated plate in an annular shape. The floating washer 17 of this embodiment can be used for tightening a side bolt of a rocker cover that does not require a sealing function. FIG. 8 shows an example in which the floating washer of this embodiment is used for fastening the side bolts of the rocker cover. The bolt 6 inserted into the flange portion 1a of the rocker cover 1 is screwed into the cylinder head 7 and the bolt 6 The floating washer 17 is interposed between the head of the rocker cover 1 and the flange 1a of the rocker cover 1.

In this floating washer 17, since the compound 13 has good heat resistance (heat resistance temperature of 4).
(00 ° C.), even when compressed by a tightening load, the layer 13 of the compound 13 has less lateral flow and less settling. Therefore, the torque holding force is good, and leakage from the washer 3 and the rocker cover gasket 2 hardly occurs as in the case of the conventional floating washer 3 described above.

Further, since the heat resistance of the compound 13 is good as described above, even if the thermal load increases, the reduction of the vibration damping effect is small.

Further, since the compound 13 has better adhesiveness to a metal plate than synthetic rubber alone, even if the tightening force is large, the pressure resistance is large (1500 kgf / cm ² to 30 kg).
00 kgf / cm ² ), compound 1 from metal plate 12
The layer of No. 3 does not peel off, and the layer of the compound 13 does not crack.

Further, the number of processing steps is small, and the manufacturing cost can be reduced. [Embodiment 2] This embodiment is suitable for a case where the floating washer itself needs to have a sealing property, for example, when the center of the rocker cover is tightened. As shown in FIG. 9, a compound 13 having the same composition as that of the first embodiment is applied to both sides of a metal plate 22 (thickness 0.3 mm) made of an aluminum plate to which a heat-resistant adhesive 21 is applied in advance, each having a thickness of 200 μm. Coated to a thickness of 2
Then, a heat-resistant adhesive 24 is applied to the surface of the layer of the compound 13 on one side. The adhesives 21 and
The thickness of each of the layers 4 is preferably about 10 ± 5 μm.

As shown in FIG. 10, a plurality of coating plates 23 coated with an adhesive 24 on one side are laminated (the top coating plate 23 does not need to be coated with the adhesive 24) and heated. Laminated plate (plate thickness 2.8m) bonded under pressure
m) Coat graphite 25 on both sides. The graphite coating is for preventing the layer of the compound 13 from sticking to the bearing surface of the bolt and the flange surface of the cover body such as the rocker cover, and preferably has a thickness of 2 to 3 μm. After the graphite coating, 140-
Heat treatment is performed in a temperature atmosphere of 160 ° C. for 40 to 60 minutes.
This heat treatment is performed using the rubber, rubber chemical and heat-resistant adhesive 2
It is carried out in order to promote a cross-linking reaction of a synthetic resin or the like mixed in the layers of 1, 24 and graphite 25. By punching the laminate thus obtained into an annular shape, a floating washer 26 as shown in FIG. 11 is obtained.

The floating washer 26 thus obtained has the same effects as those of the first embodiment, and also has excellent sealing properties because it has a layer of the compound 13 on both surfaces. Can be FIG. 11 shows an example in which the rocker cover is used for center bolt tightening. The bolt 6 inserted into the center of the rocker cover 1 is screwed into the cylinder head 7, and the head of the bolt 6 is connected to the rocker cover 1. A floating washer 26 is interposed between them.

The floating washer of the present invention can be used for fastening members other than the cover body such as the rocker cover.

[0034]

As described above, the floating washer according to the present invention has the following advantages. (1) Even when compressed by a tightening load, the compound layer has less lateral flow, less settling, good torque holding power, a washer and a rocker cover. Leakage of the gasket or other tightening object from the gasket is unlikely to occur. B) Even if the thermal load increases, the reduction in vibration damping effect is small. C) Even if the tightening force is large, the There is no delamination or cracking of the compound layer. D) The number of processing steps is small, and the manufacturing cost can be reduced. And other excellent effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a rocker cover of an internal combustion engine.

FIG. 2 is a sectional view showing a conventional floating washer.

FIG. 3 is a cross-sectional view showing an example in which the conventional floating washer is used for a side bolt tightening structure of a rocker cover.

FIG. 4 is a sectional view showing an example in which the conventional floating washer is used for a center bolt fastening structure of a rocker cover.

FIG. 5 is a sectional view showing oil leakage from a rocker cover gasket when the conventional floating washer is used for a center bolt fastening structure of a rocker cover.

FIG. 6 is a cross-sectional view showing a coating plate in a manufacturing process of Embodiment 1 of the floating washer according to the present invention, in a state where an adhesive is applied.

FIG. 7 is a sectional view showing a state in which a coating plate and a metal plate are laminated in the manufacturing process of the first embodiment.

FIG. 8 is a sectional view showing a state in which the floating washer of the first embodiment is used for a side bolt tightening structure of a rocker cover.

FIG. 9 is a cross-sectional view showing a coated plate in a manufacturing process of a second embodiment of the floating washer according to the present invention in a state where an adhesive is applied.

FIG. 10 is a cross-sectional view showing a state where coating plates are laminated in the manufacturing process of the second embodiment.

FIG. 11 shows a floating washer of the second embodiment;
It is sectional drawing shown in the state used for the center bolt fastening structure of a rocker cover.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Heat resistant adhesive 12 Metal plate 13 Compound 14 Coating plate 15 Heat resistant adhesive 16 Metal plate 17 Floating washer 21 Heat resistant adhesive 22 Metal plate 23 Coating plate 24 Heat resistant adhesive 26 Floating washer

Claims (3)

(57) [Claims] 1. A floating washer comprising a plurality of coated plates obtained by coating a metal plate with a compound layer containing a compressible fiber, an elastomer and a filler. 2. The coating plate according to claim 1, wherein a surface of the metal plate on which a heat-resistant adhesive is applied in advance on one side is coated with a layer of a compound containing a compressible fiber, an elastomer and a filler. The adjacent coating plates are bonded by heat-resistant adhesive between the surface of the compound layer of one coating plate and the surface of the other coating plate opposite to the compound layer of the metal plate. The floating metal plate according to claim 1, wherein a metal plate not coated with a compound layer is adhered to a surface of the compound layer of the outermost coating plate having no adjacent coating plate by a heat-resistant adhesive. Washers. 3. The coating plate according to claim 1, wherein both sides of the metal plate to which a heat-resistant adhesive has been applied in advance are coated with a layer of a compound containing a compressible fiber, an elastomer, and a filler. The floating washer according to claim 1, wherein the coating plate is bonded by a heat-resistant adhesive.