JPH05306653A - Engine oil pan - Google Patents

Abstract

PURPOSE:To damp vibration of an oil pan and an inner box utilizing the viscos ity of lubrication oil, and damp the vibration effectively in an easy constitution by providing shock absorbing material in a gap formed between the oil pan and the inner box, and guiding the lubrication oil in the inner box into the gap. CONSTITUTION:An inner box is installed to an inner surface of an oil pan 1. Outer form of the inner box 3 is formed to be almost similar to inner form of the oil pan 1. A micro-interval 5 is formed between the inner box 3 and the oil pan 1. Shock absorbing material 4 is provided in the gap. Lubrication inside the inner box 3 is guide d to the inner part of the gap 5 by boring a breather hole 3a at an upper part of the inner box 3 facing the gap 5, and boring an oil hole 3b at a lower part. When the oil pan 1 or the inner box makes vibration, therefore, vibration is damped by using viscosity of the lubrication oil provided in the gap 5. The vibration can thus be damped effectively in a simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an oil pan suitable for a small engine mainly used for automobiles.

[0002]

2. Description of the Related Art Generally, an engine oil pan is formed by pressing a steel plate and is bolted to the lower surface of a cylinder block. Therefore, compared with a cylinder block that is generally used as a cast product, the wall thickness is thin and the density is high, so that vibration tends to be transmitted easily. That is, since the vibration sound generated inside the engine is easily transmitted from the oil pan made of steel plate, the transmitted sound is high. Further, the vibration of the cylinder block is directly transmitted to the oil pan, and the oil pan itself vibrates to generate a so-called radiated sound which itself becomes a noise source.

Therefore, in order to prevent engine noise from being radiated to the outside from the oil pan, a vibration damping steel plate having a double structure inside and outside or pasting materials having different natural frequencies has been conventionally used. It is used and used. Particularly, in the case of the double structure, as shown in FIG. 3, the outer wall of the oil pan A is provided with an outer box C floated from the cylinder block or the oil pan by a cushioning material B such as rubber. (For example, Jitsuko Sho 56-2)
No. 2035) is known.

[0004]

[Problems to be Solved by the Invention] However, the former,
That is, in the type in which the soundproof box is further covered on the outside of the oil pan, the structure is generally complicated and the appearance is large, and water may easily enter between the oil pan and the soundproof box, which may cause corrosion. .. The latter, that is, the one with a similar inner wall inside the oil pan, was effective for transmitted sound because the inner and outer walls were double walls, but oil could freely enter and leave between the inner and outer walls. Because it was possible, it had almost no effect on radiated sound.

In view of the above problems, the present invention provides an inner box inside a steel plate oil pan to reduce the transmitted sound as an inner and outer double wall, and at the same time, the oil pan is vibrated by the vibration transmitted from the cylinder block. The purpose is to reduce radiation noise generated by vibration as much as possible.

[0006]

An engine oil pan according to the present invention for solving the above problems comprises an oil pan and an inner box attached to the inner surface of the oil pan. Formed in a shape similar to the inner surface shape, a small gap is formed between the inner box and the inner surface of the oil pan, a cushioning material is interposed in the gap, and the upper part of the inner box facing the gap is breathed. The vent hole and the oil passage hole are provided in the lower part to guide the lubricating oil inside the inner box into the gap.

[0007]

[Operation] The inner box of the oil pan has an outer surface that is similar to the inner box, so there is a slight gap between them. Lubricating oil inside enters into the gap through oil passage holes provided in the inner box, and air in the gap escapes into the inner box through the breather hole in the upper portion. The liquid level of the lubricating oil in the gap is higher than that in the inner box due to the surface tension because the gap is small. When the steel plate forming the oil pan is vibrated by noise generated inside the engine or vibration of the cylinder block, the lubricating oil inevitably moves in an attempt to change the size of the gap. However, since the gap is relatively small, the lubricating oil filled in the gap cannot move quickly, and the movement consumes noise energy due to the flow resistance between the lubricating oil and the wall surface. Vibration of a wide surface is stopped.

[0008]

[Examples] The present invention will be described below with reference to illustrated examples. In FIG. 1, reference numeral 1 denotes a so-called steel plate oil pan in which a steel plate is press-molded and anticorrosive coating is applied. The bottom portion 1a of the oil pan 1 is configured such that one side is shallow and the other side is deep,
A suction port of an oil pump (not shown) opens in the deep portion. 1b is a flange surface for attaching to the cylinder block 2, and 1c is a bolt hole.

In the present invention, an inner box 3 made of the same steel plate is attached to the inner surface of the oil pan 1 and has an outer surface having a shape similar to that of the inner surface. As shown in FIG. 2, the oil pan 1 and the inner box 3 are bolted to the lower surface of the cylinder block 2 via a spacer 4a and bolts 4b with a rubber-like cushioning member 4 interposed therebetween. Therefore, a narrow gap 5 is formed between the oil pan 1 and the inner box 3.

The gap 5 between the inner surface of the oil pan 1 and the outer surface of the inner box 3 is preferably as narrow as possible in terms of noise reduction effect, and is preferably about 0.5 to 1 mm. Rubber or rubber-like synthetic resin is adhered to several places in the gap 5 as a cushioning material 5a. Due to a manufacturing error, the oil pan 1 and the inner box 3 may partially contact each other with metal. Care is taken not to generate a clicking noise.

The gap 5 and the inner surface of the inner case 3 are communicated with each other by a breather hole 3a provided in the upper part of the inner case 3 and an oil passage 3b provided in the lower part. Therefore, when oil is supplied to the oil pan 1, the lubricating oil enters the inner box 3, and then the air present in the gap 5 is removed from the breather hole 3a into the inner box 3 while the lower oil passage 3b is provided.
Flows into the gap 5. The sizes of the breather hole 3a and the oil passage hole 3b are preferably set as small as possible in order to prevent sound from leaking. In this embodiment, the lower oil passage 3b is provided directly above the drain bolt 3c, so that when the lubricating oil is replaced, the lubricating oil can be quickly discharged even if the oil passage 3b is not large. I'm supposed to be. A reinforcing plate 1d is welded to the bottom surface of the oil pan 1 and has a bolt hole into which the drain bolt 3c is screwed.

Since the oil pan 1 according to the present invention is constructed as described above, the sound generated inside the engine, such as the combustion sound and the sound of the piston or the crankshaft while the engine is operating, is not used for the inner surface of the inner box 3. However, if the surface of the inner box 3 moves even slightly, the lubricating oil filling the gap 5 between the oil pan 1 and the inner box 3 moves. Therefore, the energy of noise is attenuated by the adhesive friction between the lubricating oil and the wall surface, so that the internal sound does not pass through the oil pan 1 and the noise emission is reduced.

Similarly, when the vibration is transmitted to the oil pan 1 through the cylinder block 2 like the combustion vibration of the engine or the vibration of the valve train, the natural frequency of the oil pan 1 is different from that of the inner box 3. Since the gap 5 changes in size and magnitude because it tries to vibrate in different phases and periods, the noise energy is attenuated by the adhesive friction between the lubricating oil and the wall surface that move to follow the change, and as a result, it is dissipated. Noise is reduced.

[0014]

As described above, according to the present invention, the oil pan 1
A small gap 5 is provided between the inner surface of the inner casing 3 and the outer surface of the inner casing 3, and the gap 5 is filled with lubricating oil, and either the oil pan 1 or the inner casing 3 will resonate due to internal sound or vibration of the engine. In this case, the viscosity of the lubricating oil intervening in the gap 5 is used to damp it, and its noise reduction effect is remarkable, and the structure is simple and there is no wear and tear for a long time. This is a great practical effect that can maintain the effect.

[Brief description of drawings]

FIG. 1 is a perspective view of an oil pan 1 according to the present invention.

FIG. 2 is a sectional view of an oil pan portion of the engine.

FIG. 3 is a sectional view corresponding to FIG. 2 showing a conventional example.

[Explanation of symbols]

1 oil pan 2 cylinder block 3 inner box 3a breather hole 3b oil passage hole 4 cushioning member 5 narrow gap

Claims (1)

[Claims] 1. An oil pan and an inner box attached to the inner surface of the oil pan, wherein the outer surface of the inner box is formed in a shape substantially similar to the inner surface of the oil pan, and between the inner box and the inner surface of the oil pan. A small gap is formed in the inner space, a cushioning material is interposed in the gap, and a breather hole and an oil passage hole are formed in the upper part of the inner box facing the gap and the lubricating oil inside the inner box is filled in the gap. An oil pan for the engine that is configured to lead inside.