JPS595785B2 - engine oil pan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine oil pan, and particularly to its noise reduction structure.

Generally, an engine generates vibrations in response to its operation, and the engine vibrations are transmitted to an oil pan attached to a lower part of the engine by a tightening member, and are propagated to the outside as noise.

Of this noise, the one caused by the special low-frequency vibration can be heard as a loud noise.

Conventionally, as in Utility Model Application No. 55-28778, a bead extending vertically is formed on the side surface of the oil pan, and this bead improves the rigidity of the oil pan and eliminates low frequency components, thereby reducing noise. Techniques have been proposed to reduce the occurrence of.

However, in the above proposed structure, multiple beads are formed at equal intervals, and the sizes of the surfaces divided by these beads are equal, and the natural frequencies of each divided surface match, so that the vibration due to low frequency vibration is Although noise is reduced, a resonance phenomenon occurs at a specific p-frequency, resulting in a large amount of noise as a whole.

In other words, if the areas of the surfaces connected on both sides of the bead are equal and the natural frequencies match, the surfaces connected on both sides will resonate strongly with the bead as a node at the resonance frequency, resulting in increased noise. It is something.

In view of this, the present invention provides an engine oil pan in which a plurality of beads are arranged at uneven pitches, thereby reducing both noise caused by low frequency vibrations and noise caused by resonance phenomena. .

Embodiments of the present invention will be described below with reference to the drawings.

In the drawings, reference numeral 1 denotes an oil pan for storing lubricating oil, which is attached to the lower part of the engine E by a plurality of fastening members 2;
3 is a cylinder head of engine E, and 4 is a cylinder block.

The oil pan 1 has a flange-like tightening surface 1a at the upper end.
is fixed to the lower part of the engine E by abutting against the lower end of the cylinder block 4 of the engine E and tightening the bolt with a member 2.

The oil pan 1 has a plurality of groove-shaped beads 5 extending in the vertical direction formed on its side surface in parallel and at unequal pitches.

In other words, in the case shown, the interval (pitch) between each bead 5 ■
1 to 4 are all provided differently.

Further, the upper end portion 5a of the bead 5 is provided at a position below the surface 1a by a predetermined height.

Further, the tightening member 2 is provided so as to be located between the beads 5.

To explain the operation of the above embodiment, since a plurality of beads 5 are formed, the rigidity of the entire oil pan 1 is improved and low frequency vibrations are eliminated, and each bead 5 is arranged at an uneven pitch. The spacing between beads 5 ■□ to ■4 is all set differently, and the areas of the dividing surfaces formed between each bead 5 are different, and the natural frequencies of each surface are also different accordingly. do.

Therefore, the noise caused by the 1-resonance phenomenon can be reduced and eliminated together with the noise caused by low frequency vibration.

In addition, in the above embodiment, the upper end 5a of each bead 5 is provided so as to be located between the clamping members 20, so that the rigidity of the peripheral part of the clamping member 2 is maintained low, and its damping effect suppresses high frequency vibrations. As a result, transmission of high frequency vibrations to the bead 5 is reduced, and noise caused by high frequency vibrations can also be reduced or eliminated.

In addition, when each bead 5 is arranged at an unequal pitch, the setting of the unequal pitch is such that the 7' beat, which occurs due to interference due to the difference in the natural frequencies of the dividing planes, is outside the audible frequency range. Do what you want.

Further, in the above embodiment, the interval between beads 5 is
4 are all set to be different, but this can be done by setting them at unequal pitches such that at least the natural frequencies of adjacent dividing surfaces do not match. 13 or I2 = I4), no resonance vibration occurs.

In this case, the noise reduction effect is slightly lower than that of all different uneven pitches.

Therefore, according to the present invention as described above, by arranging a plurality of beads at unequal pitches, the natural frequencies of the surfaces divided by the beads can be made different to prevent the generation of resonance vibration. The formation of the beads improves the rigidity of the entire oil pan and eliminates low-frequency vibrations, while at the same time preventing the generation of noise due to resonance phenomena, and has an excellent overall noise reduction effect.

[Brief explanation of the drawing]

The drawing is a schematic side view of an engine showing one embodiment of the present invention. E...Engine, 1...Oil pan,
2...Tighten the parts, 4...Cylinder block, 5...Bead.

Claims (1)

[Claims] 1. An engine oil pan provided at a lower part of the engine and having a plurality of beads formed therein, wherein the plurality of beads are arranged at uneven pitches.