JPS6228676Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to an oil pan for an automobile engine that suppresses vibration. Oil pans are a major source of noise in many engines and vehicles, and efforts have been made to reduce the sound radiated from the oil pan. Conventional methods for this purpose include (1) increasing the thickness of the oil pan, (2) welding a reinforcing plate to the oil pan, and (3) adding ribs during press forming of the oil pan. I found a way to attach it. Furthermore, as a method that is being tried as a future issue, (4) oil pan molding using double steel plates (hereinafter referred to as vibration damping steel plates) with a resin layer sandwiched in between;
(5) Anti-vibration connection means for preventing vibration transmission from the cylinder block, such as rubber floating in the oil pan, have been proposed. In general, it is said that the sound from the oil pan is dominated by structure-transmitted sound due to vibrations transmitted via the cylinder block, rather than transmitted sound from the explosion inside the engine. Considering this point, the above
Measures (1), (2), and (3) are effective because they increase the rigidity of the oil pan and reduce the vibration level, but their effectiveness is limited because they do not involve loss of vibration energy. . In addition, with the method (4) above, vibration energy loss is achieved through shear deformation of the resin layer, which is a viscoelastic body, and a remarkable effect of reducing radiated sound can be obtained, but the press forming of the oil pan, which requires deep drawing, is extremely difficult. The problem was that it became difficult. It has been pointed out that wrinkles are particularly likely to form on the oil seal surface, and even if wrinkles do not form, after the bolts are tightened to the cylinder block, the intermediate resin layer is crushed and torque is reduced, causing oil leakage. . Furthermore, although the above method (5) is a means for reducing the transmission of vibration to the oil pan and is said to have the best vibration-proofing effect experimentally, it is
There was a problem in that it was extremely difficult to ensure long-term durability under conditions of vibration and load as temperatures rose to around 30°F. Moreover, with this method, if even a portion of the mounting bolt comes into contact with both the cylinder block and the oil pan, it is recognized that the vibration damping effect on the oil pan will be extremely reduced. This invention aims to reduce the sound radiated from the engine oil pan by using the vibration suppression (hereinafter referred to as vibration damping) function due to the vibration energy loss of the viscoelastic material, similar to the vibration damping steel plate, and also aims to reduce the sound radiated from the engine oil pan. The aim was to solve processing problems and the problem of oil leakage after tightening the oil pan to the cylinder block, and also to create a low-cost vibration damping structure that was tailored to the shape of the oil pan and the situation in which radiated sound was generated. Its purpose is to provide oil pans for automobile engines. Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of an oil pan for an automobile engine according to the present invention, in which an oil pan body 1 made of a pressed steel plate has a partially stepped and recessed oil pan. It has a recess 1a for reservoir, and the flat area of the recess 1a is made wide. A flange surface 1b is formed in the upper part of the oil pan body 1, and a plurality of bolt holes 1c are bored in the flange surface 1b.
The oil pan body 1 is attached to the cylinder block side (not shown) through a bolt (not shown) passed through the bolt hole 1c from the bolt tightening surface 1d side on the back side of b.
is ready to be installed. The oil pan body 1 has a viscoelastic first layer coating 2 coated on its outer surface, a second layer coating 3 coated thereon, and a flat and relatively wide surface. A third layer plate member 4 made of a highly rigid material is held on the second layer coating 3 by utilizing its adhesive properties when uncured. In this oil pan, the second layer coating 3 is overlaid on a portion of the first layer coating 2 excluding the bolt tightening surface 1d. When the first layer coating 2 receives heat transfer from the engine oil temperature during steady engine operation and reaches a temperature of 80 to 100 degrees Celsius,
This layer has a loss coefficient of 0.5 or more and a Young's modulus of 10 ⁷ to 10 ⁸ dyne/cm ² in this temperature range. Then, by overlapping a layer with a higher Young's modulus, that is, a second layer coating 3 and a third layer plate member 4, it functions as a viscoelastic layer of the vibration damping material with a constraining layer. Vibration energy due to vibrations transmitted from the engine to the oil pan body 1 is absorbed by shear deformation. The second layer coating 3 serves as a constraining layer for the first layer coating 2.
The layer has a Young's modulus of 5.0 to 10 ¹⁰ dyne/cm ² or more in the temperature range of 80 to 100°C. The higher the Young's modulus is, the more preferable it is, but considering the requirements such as paintability and adhesion with the first layer coating 2 and the third layer plate member 4, the materials for the second layer coating 3 are as follows. is suitable for use. The third layer plate member 4 has a Young's modulus equal to that of the second layer coating film 3.
It is higher and has a function as a constraining layer like the second layer coating film 3. Since its function as a restraining layer is superior to that of the second layer coating film 3, the third layer plate member 4
The second layer coating film 3 in the range where it can be provided is the third layer plate member 4
The minimum film thickness required for pasting is sufficient. In a preferred embodiment of the present invention, the first coating film 2 can be obtained by using BX-100 Undercoat (trade name) manufactured by Kansai Paint Co., Ltd., and its film thickness is the same as that commonly used in oil pans of automobile engines. Na1.2~
When painting on a 1.6mm thick steel plate, 0.1 to 0.3mm is appropriate. If the thickness is outside this range, that is, if it is lower than 0.1 mm, the composite loss coefficient will drop sharply during operation, and if it is higher than 0.3 mm, there is no restriction on the damping function, but even if it is thick, there will be no additional effect. Small, impact on bolt tightening area, process,
Excluded for cost reasons. The second layer coating 3 is Kansai Paint Co., Ltd.'s BX-100 Top Coat (product name), Nippon Rubber Co., Ltd.'s V606 (product name), and Sanyo Chemical Industries, Ltd.'s Sunform IC-
3072 (trade name), the main component of which is urethane cement, etc., and the film thickness is 1.0
Appropriately, the thickness is within the range of ~5.0 mm, more preferably approximately 1 to 2 times the thickness of the oil pan body used. The damping effect improves as the film thickness increases, but the above film thickness range is appropriate considering the limitations due to the curing process and volumetric shrinkage over time, as well as weight, cost, workability, etc. be. Moreover, the above-mentioned coating material has a small volumetric shrinkage and is suitable for use because it is excellent in weight, cost, workability, etc. In addition, for the part with the second layer thickness 3 on which the third layer plate member 4 is provided, the minimum thickness required for adhesion is sufficient, but it is difficult to apply strict separation, and generally it is 0.1 mm or more. The film thickness is appropriate. The third layer plate member 4 can be obtained from a flat metal plate or asbestos slate plate having a high Young's modulus, and the thickness of the material is thinner as the Young's modulus is higher, assuming that the function as a constraining layer is constant. The plate thickness may be
A common thickness range is 0.5-4.0mm. For example, the thickness of the third layer plate member 4 is Young's modulus 2.1×
When using a 10 ¹² dyne/cm ² steel plate, it is preferable to have a thickness similar to that of the oil pan body 1 (in the range of 1.2 to 1.6 mm), and when using an asbestos slate plate, the thickness of the oil pan body 1 should be the same. It is preferably about twice as much. Although the third layer plate member 4 has a higher Young's modulus than the second layer thickness 3 and has a great function as a restraining layer, it requires precise molding to be applied to the curved shape of the oil pan, making it impractical. A flat plate is suitable for use because it is not a target. Furthermore, while the second layer coating film 3 shows a tendency for Young's modulus to decrease at high temperatures, the third layer plate member 4, whose Young's modulus remains essentially unchanged, exhibits its function as a constraining layer as the temperature increases. be. Next, the functions and effects of this embodiment will be explained. The oil pan is attached to the cylinder block when in use. During steady engine operation, the first coating film 2 receives heat transfer from the engine oil temperature, and
It is a layer with a loss coefficient of 0.5 or more and a Young's modulus of 10 ⁷ to 10 ⁸ dyne/cm ² when the temperature reaches the temperature range of °C. By stacking the layered plate members 4, it acts as a viscoelastic layer of what is generally called a vibration damping material with a constraining layer. Therefore, the vibration energy from the engine transmitted to the oil pan body 1 is absorbed by shear deformation. The constrained vibration damping material referred to here is a vibration damping material in which a viscoelastic layer is closely attached to one side of the substrate, and a constraining layer with a high Young's modulus is provided on the surface. Energy is absorbed by the shear deformation that occurs in the viscoelastic layer due to the restraint. Looking at this in the present invention, the substrate is the oil pan body 1, the viscoelastic layer is the first layer coating 2, and the constraint layer is the part where only the second layer coating 3 (curved surface part) and the second layer This corresponds to the overlapping portion (plane portion) of the coating film 3 and the third layer plate member 4. Furthermore, the reason why there are two types of constraint layers depending on the parts of the oil pan body 1 as described above is to match the characteristics of the material that constitutes the constraint layer with the characteristics based on the shape of the oil pan body 1. . That is, as for the characteristics of the constraining layer material, in the case of the second layer coating film 3, it can be applied to both flat and curved parts of the oil pan body 1, but the Young's modulus is relatively low, and therefore it is difficult to apply low frequency It has a small effect on reducing the radiated sound in the region of On the other hand, in the case of the third layer plate member 4, it can only be applied to flat surfaces, but the material has a high Young's modulus, and the Young's modulus can be considered unchanged in the above temperature range. The material can be selected, and the oil pan body 1
Characteristics resulting from the shape of the curved surface are that the curved portion has high rigidity and is likely to be a source of high-frequency radiated sound, and the flat portion has low rigidity and is likely to be a source of low-frequency radiated sound. Next, the reason why the Young's modulus and the loss coefficient are numerically limited will be described. It is known that the loss coefficient η is given by the following equation. η=12gη ₂ /1+2g+(1+η ₂ )g ²・E ₃ h
₃ /E ₁ h ₁・(h ₃₁ /h ₁ ) ² However, E ₁ , E ₃ : Young's modulus of the substrate and restraining material (N/cm ² ) h ₁ , h ₃ : Thickness of the substrate and restraining material ( m) h ₃₁ : Equivalent bending stiffness (=[h ₂ +12 (h ₁ + h ₃ )]/12) η ₂ : Loss coefficient of viscoelastic material g: shear parameter g=f _S /f,

[Formula] G ₂ : Shear modulus of elasticity of viscoelastic material h ₂ : Thickness of viscoelastic material (m) ρ ₁ : Density of substrate (Kg/m ³ ) The larger the loss coefficient, the greater the vibration damping effect. As a result, the radiated sound due to the vibration of the substrate (oil pan main body 1) becomes smaller, but it is generally said to be effective when the value of η is 0.05 or more. The significance of the above-mentioned numerical limitation is primarily determined by satisfying η≧0.05, taking into account the construction constraints described from page 6, line 16 to page 9, line 4. In particular, in an engine in which an oil pan made of the above material and film thickness is attached to the cylinder block, sound is insulated from parts of the engine other than the oil pan with glass wool and lead, and the sound is captured by a microphone installed near the oil pan. According to sound pressure tests, the sound pressure due to the sound radiated from the oil pan is:
It was confirmed that the oil pan body 1 was reduced by more than 2 decibels compared to the oil pan body 1 alone. Furthermore, the oil pan in this embodiment is coated only on the outer surface to give the first layer coating 2 sufficient anti-rust power, and is assembled to the engine block early after the oil pan is manufactured. In this way, it is possible to omit rust prevention treatment on the inner surface of the oil pan. Therefore, conventional oil pans are generally electrodeposited on both the inside and outside surfaces.
Anti-rust coating was applied using AP coating, etc., but if the inner surface is coated, the inner coating may peel off or the oil filter may become clogged due to the action of high-temperature engine oil over a long period of time. It is possible to solve the problem and reduce the cost increase due to damping of oil pan vibration. Figure 3 shows a second embodiment of the oil pan according to the present invention, and this oil pan is shown in Figures 1 and 2.
A rust-preventing coating layer 5 is applied to the inner and outer surfaces of the oil pan main body 1 shown in the figure, and the same coating as in the first embodiment is applied to the outer surface thereof to suppress vibration. The thickness of this anticorrosion film layer 5 is generally 0.02 mm or less, and its influence on the vibration damping effect is substantially negligible. However, the inner coating film should not peel off due to the action of high-temperature engine oil for a long period of time, and the first layer coating film 2, the second layer coating film 3, and the third layer plate member 4 should be protected against rust on the outer surface side. It is necessary to sufficiently confirm that interlayer peeling does not occur due to overlaying on the coating layer 5. According to this embodiment, in addition to the functions and effects of the above-mentioned first embodiment, the oil pan of this embodiment has a preferable effect for preventing rust from forming from the inner surface when shipped as a spare part to the market. has. FIG. 3 shows a third embodiment of the present invention, in which the oil pan body 1 shown in FIGS. This is what I did. Therefore, the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. According to this embodiment, in addition to the effects of the above-mentioned first embodiment, the third layer can be used in cases where a higher vibration damping effect of the oil pan is required, or where the flat area of the oil pan is relatively small. In cases where the range in which the plate member 4 can be provided is narrow and the necessary vibration damping effect cannot be obtained with vibration damping on only one side, a preferred embodiment that should be adopted is shown, and has the effect of satisfying these demands. Therefore, according to the present invention having the above-described configuration, vibrations are transmitted from the cylinder block to the oil pan when the engine is operating, and it is possible to reduce the sound radiated from the oil pan caused by resonance or forced vibration. becomes. As a result, it is possible to comply with vehicle exterior noise regulations, and at the same time, it is possible to increase the commercial value of the automobile by silencing the interior sound of the vehicle and the sound near the vehicle during engine idling. especially,
In a situation where it is difficult to take measures against diesel engines to comply with vehicle exterior noise regulations, the automobile engine oil pan according to the present invention can be said to be truly excellent as a means for reducing vehicle exterior noise. In addition, compared to applying an oil pan using damping steel plates, which is the conventional means of reducing noise radiated from oil pans, this invention avoids problems that are difficult to solve in each process of press forming, welding, and painting. It also has the advantage of making it difficult for engine oil to leak due to a reduction in bolt tightening torque at the seal portion.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first embodiment of the present invention;
Figure 2 is a longitudinal sectional view taken along the - line in Figure 1;
The figure is a longitudinal sectional view showing a part of the second embodiment of the present invention, and FIG. 4 is a longitudinal sectional view showing a part of the third embodiment of the invention. 1... Oil pan body, 2... First layer coating film, 3
...Second layer coating film, 4...Third layer plate member.

Claims (1)

[Scope of utility model registration request] On the oil pan body, the Young's modulus in the temperature range of 80 to 100°C is 10 ⁷ to 10 ⁸ dyne/cm ² and the loss coefficient is
A first layer coating film with a viscoelasticity of 0.5 or more is provided, and a Young's modulus in a temperature range of 80 to 100°C is provided on the first layer coating film.
A second layer coating film having a thickness of 5.0×10 ¹⁰ dyne/cm ² or more is provided, and the Young's modulus in the temperature range of 80 to 100°C is the second layer coating film on the flat surface of the oil pan body. An oil pan for an automobile engine, characterized in that a third layer plate member made of a highly rigid material is larger than the layer coating film.