JPH0564443U - Side cover of engine cylinder block - Google Patents

Abstract

(57) [Summary] [Structure] A cover attached to the side portion of an engine cylinder block, in which a foamed silicone sheet 8 having a surface for fitting to the surface of the side portion of the engine cylinder block is provided on the surface of the reinforcing plate 7. [Effect] Since the foamed silicone sheet 8 fills the space between the side portion 3 of the engine cylinder block and the reinforcing plate 7 without any gap, the sound generated at the time of engine rotation is effectively absorbed and reduced, and at the same time, the side It can be easily attached to the part 3, has excellent water resistance and oil resistance with the side part 3, and can withstand use at high temperatures.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a side cover for an engine cylinder block that reduces noise generated when the engine rotates.

A crankcase with a built-in crank receives rotational vibration of the crank when the engine rotates, and generates a rotating sound or vibration.

Conventionally, as a noise reduction device for such an engine, as shown in FIG. 2, a rubber-made vibration-damping material 2B that also serves as a sealing material is joined to the surface of a thin steel plate 2A, and further glass wool aluminum is used. The side cover 2 in which the covered soundproof material 2C is joined was used.

By attaching such a side cover 2 to the engine crankcase 1, rotational noise, vibration noise, etc. generated by rotational vibration of the crank are absorbed and attenuated by the vibration isolator 2B and the noise isolator 2C, and reduced. It aims to reduce the noise generated in the entire engine.

[0005]

[Problems to be solved by the device]

 However, in such a conventional side cover 2, it is necessary to bond the rubber-molded vibration damping material 2B, which requires time and cost for the bonding process.

[0006] In order to obtain a sufficient vibration damping and soundproofing effect, it is necessary to take a sufficient thickness of the rubber of the vibration damping material 2B. However, if the thickness of the vibration damping rubber is increased, the material cost increases and the weight also increases. In both cases, there is a limitation in increasing the thickness of the anti-vibration rubber because it requires an extra space, and therefore it was not possible to obtain sufficient noise and vibration damping effects.

Regarding the soundproofing material 2C, it is necessary to stick an aluminum film around the molded product of glass wool without a gap due to the problem of water resistance, but since this work is performed manually, the cost is high and at the same time the glass wool is expensive. The effect on the human body cannot be ignored.

Further, it is possible to increase the thickness of the soundproof material 2C to reduce noise and vibration, but this is limited because of the same reason as the antivibration rubber.

Further, as shown in FIG. 3, the crankcase 1 has ribs 4 and projections 5 having a complicated structure on the side portion 3 thereof in order to ensure weight reduction and strength, and further, the above-mentioned parts are provided. When such a side cover 2 is attached, a space 6 is formed between the soundproof material 2C and the crankcase 1, and noise and vibration resonate and increase due to this space 6.

In order to fill this space, it is impossible to mold the glass wool provided on the surface of the soundproof material 2C so as to completely adhere to the shape of the crankcase 1.

Further, it is difficult to mold the rubber of the vibration-proof material 2B in place of the sound-proof material 2C so as to be in close contact with the shape of the crankcase 1, and the molding cost thereof becomes high. That is, it is impossible to completely fill the mating surface of the crankcase 1 with both the vibration damping material 2B and the soundproofing material 2C.

[0012]

[Means for solving problems]

 In order to solve the above problems, the present invention proposes a side cover for an engine cylinder block in which a foamed silicone sheet having a fitting surface for the side surface of the engine cylinder block is provided on the surface of the reinforcing plate. is there.

The side cover according to the present invention injects a liquid foam silicone resin between the side portion of the engine cylinder block such as a crankcase and the reinforcing plate provided at a predetermined interval and foams and cures this resin at a predetermined temperature. Manufactured by forming a foamed silicone sheet.

As such a liquid foamed silicone resin, for example, foamed silicone resin ThreeBond 5277C (trade name) is preferable, and since this foamed silicone resin is almost harmless to the human body, it is excellent in workability and safety. At the same time, since it has a low viscosity of 100 poise or less at the time of injection, it excels in finely filling the side part of an engine cylinder block such as a crankcase with a complicated rib structure, and it completely forms a side part and a reinforcing plate. It becomes possible to fill in the gaps.

[0015]

[Action]

 According to this invention, a foamed silicone sheet having fine air bubbles inside can be formed between the side portion of the engine cylinder block and the reinforcing plate to have an appropriate thickness, so that the rotation noise generated by the rotation vibration of the crank is generated. It is possible to effectively absorb and attenuate vibration noise.

[0016] Furthermore, since the gap between the side portion of the engine cylinder block having a complicated rib structure and the reinforcing plate is completely filled with the foamed silicone sheet, the rotation noise, vibration noise, etc. generated by the rotational vibration of the crank are not generated. There is no space to resonate and increase.

Further, since the foamed silicone sheet is embedded in the side portion of the engine cylinder block having a complicated rib structure or the surface of the reinforcing plate and does not separate, it is not necessary to attach it to the side portion, thereby reducing the cost. be able to.

Further, in this invention, since the foamed silicone sheet excellent in water resistance and engine oil resistance is embedded in the side portion of the engine cylinder block or the surface of the reinforcing plate without a gap, it is compared with the above-mentioned glass wool. However, it has excellent water resistance and oil resistance.

Further, the side cover according to the present invention makes it possible to withstand use at high temperature because the foamed silicone sheet having excellent heat resistance is brought into contact with the side portion of the engine cylinder block.

【Example】

 Hereinafter, the present invention will be described in detail based on the illustrated embodiments. As shown in FIG. 3, a reinforcing plate 7 is provided at a predetermined interval on the side part 3 of the crankcase 1, and a liquid silicone foam resin (trade name: ThreeBond 5277C) is injected between the side part 3 and the reinforcing plate 7. Then, it is foamed and cured.

As a result, the side cover 2 having the foamed silicone sheet 8 of a predetermined width fitted on the surface of the reinforcing plate 7 and the surface of the side portion 3 is obtained.

FIG. 4 shows the noise reduction effect using the side cover according to the present invention in comparison with the conventional example. The vertical axis represents the noise level (dB) and the horizontal axis represents the frequency of noise (Hz). The curve A in the figure is the noise level when the side cover according to the present invention is attached to the side portion of the crankcase, the curve B is the noise level when the side cover shown in FIG. 2 is attached, and the curve C is the reinforcing plate. It shows the noise level when only the only one is installed.

The noise measurement of these side covers while the engine is rotating is the result of measuring with a microphone at a position of about 1 m from the side covers.

As a result, the side cover according to the present invention has an average of about 1.5 dB in the high frequency range (1 to 2 KHz) as compared with the side cover using the conventional anti-vibration rubber / glass wool shown in FIG. It was found that it exhibits a noise reduction effect.

[0024]

[Effect of the device]

 In short, according to the present invention, since the space between the side portion of the engine cylinder block and the reinforcing plate is completely filled with the foamed silicone sheet, the sound generated during engine rotation is effectively absorbed and reduced. ..

The side cover according to the present invention can be easily attached to the side portion, has excellent water resistance and oil resistance with the side portion, and can withstand use at high temperatures. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing an example of use of a conventional side cover.

FIG. 3 is an exploded perspective view showing a side portion of an engine cylinder block.

FIG. 4 is a diagram showing a noise reduction effect using the side cover according to the present invention in comparison with a conventional example.

[Explanation of symbols]

 1 Engine Crankcase 2 Side Cover 3 Side 7 Reinforcing Plate 8 Foamed Silicone Sheet

Claims (1)

[Scope of utility model registration request] 1. A side cover for an engine cylinder block, wherein a foamed silicone sheet having a surface for fitting to the side surface of the engine cylinder block is provided on the surface of the reinforcing plate.