JPH0835443A - Vibration control internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a vibration-damping internal combustion engine capable of not only suppressing the occurrence of vibration of a specific frequency but also damping vibrations of frequencies other than the specific frequency. [Structure] The crankshaft 5 is a cylinder block 1
Is supported by a bearing bulk 2 and a bearing cap 3 which are integrally formed with The damping plate 8 is installed at the lower end of the bearing cap by bolts 41 and 42 that attach the bearing cap to the bearing bulk 2. The width and depth of the bent portion 83 provided in the vertical portion 82 of the vibration damping plate are adjusted so that the natural vibration frequency of the vibration damping plate matches the natural vibration frequency of the bearing cap, and vibration of the bearing cap is suppressed. Further, since the vertical portion 82 of the damping plate is inserted into the lubricating oil 7, the vibration of the bearing cap is damped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control type internal combustion engine, and more particularly to a vibration control type internal combustion engine capable of suppressing and damping the vibration of a bearing cap.

[0002]

2. Description of the Related Art In a reciprocating internal combustion engine, vertical movement of a piston in a cylinder is converted into rotational movement by a crankshaft. The crankshaft has a bearing bulk integrally formed with a cylinder block and a bolt on the bearing bulk. It is supported by a bearing cap that is tightened.

Therefore, the bearing cap is vibrated by the force of front and rear and up and down at each explosive stroke, and leaks to the outside as noise. In order to solve the above problem, a low noise internal combustion engine in which vibration generated by a bearing cap is reduced has been proposed (see Japanese Utility Model Laid-Open No. 57-8338).

[0004]

In the low noise internal combustion engine according to the above proposal, a dynamic damper composed of an elastic body and a mass body mounted via the elastic body is installed in the front and rear direction of the lower end of the bearing cap. Therefore, it is possible to suppress the occurrence of vibration with respect to the vibration of the specific frequency.

However, the dynamic damper cannot suppress the generation of vibration other than the specific frequency, and the vibration once generated is very difficult to attenuate. The present invention has been made in view of the above problems, and provides a vibration-damping internal combustion engine capable of not only suppressing the occurrence of vibration of a specific frequency but also damping vibrations other than the specific frequency. With the goal.

[0006]

A vibration-damping internal combustion engine according to a first aspect of the present invention includes a cylinder block, a bearing bulk provided on the cylinder block, and a crankshaft axially supported so as to face the bearing bulk. A bearing cap, an oil pan installed below the cylinder block for storing lubricating oil, and a damping plate attached to the lower end of the bearing cap and dipped in the lubricating oil stored in the oil pan are provided.

The vibration-damping internal combustion engine according to the second invention further comprises an oil strainer attached to the lower end of the bearing cap, and an elastic body arranged between the bearing cap and the oil strainer.

[0008]

In the vibration damping internal combustion engine according to the first aspect of the invention, the vibration generated in the bearing cap is suppressed by the vibration damping plate and the vibration of the vibration damping plate is damped by the lubricating oil. In the vibration damping internal combustion engine according to the second aspect of the invention, the oil strainer and the elastic body function as a dynamic damper to suppress and damp the vibration generated in the bearing cap.

[0009]

1 and 2 are a front sectional view and a side sectional view of a vibration damping internal combustion engine according to a first invention. A bearing bulk 2 is formed integrally with the cylinder block 1 at the bottom of the cylinder block 1.

The bearing cap 3 is attached to the lower end of the bearing bulk 2 by two bolts 41 and 42. The crankshaft 5 is pivotally supported by being sandwiched between the bearing bulk 2 and the bearing cap 3. An oil pan 6 is attached to the lower surface of the cylinder block 1 so as to cover the bearing cap 3.
Lubricating oil 7 for lubricating the crankshaft, piston, etc. is stored therein.

Further, at least one damping plate 8 is attached to the lower end of the bearing cap 3 by means of bolts 41 and 42. The damping plate 8 extends into the lubricating oil 7 stored in the oil pan 6. There is. FIG. 3 is a perspective view of the damping plate 8, which is composed of a mounting flange 81 to the bearing cap 3 and a vertical portion 82 extending into the lubricating oil 7.

The vertical portion 82 is provided with a bent portion 83 having a width X and a depth Y. By adjusting the width X and the depth Y, the natural vibration frequency of the damping plate 8 can be changed. Therefore, by adjusting the width X and the depth Y of the bent portion 83 so that the natural vibration frequency of the damping plate 8 matches the natural vibration frequency of the bearing cap 3, the crankshaft 5
It is possible to suppress the vibration of the bearing cap 3 excited by the vibration of the specific frequency.

Further, since the vertical portion 82 of the damping plate 8 is immersed in the lubricating oil 7, even if the cap vibrates at a frequency other than the specific frequency, the vibration is transmitted to the damping plate 8. Lubricating oil acts as resistance in the vibration damping plate 8 mainly in the front-rear direction (crankshaft direction), and the vibration is damped. FIG. 4 is a side sectional view of another embodiment of the damping plate 8 of the damping internal combustion engine according to the first invention, in which a horizontal plate 84 is attached to the vertical portion 82.

By attaching the horizontal plate 84, the lubricating oil becomes a resistance against the vertical vibration of the damping plate, and not only the vertical vibration of the bearing cap 3 can be attenuated, but also the lubricating oil It is possible to suppress the scattering. FIG. 5 is a side sectional view of a vibration damping internal combustion engine according to a second aspect of the present invention. Instead of a part of the plurality of vibration damping plates 8, an oil strainer 9 for sucking the lubricating oil 7 in the oil pan 6 is shown.
The support portion and the lubricating oil discharge port are attached to the bearing cap 3 and the cylinder block via the elastic body 10 (for example, rubber or resin material).

That is, by determining the thickness of the elastic body 10 in consideration of the mass of the oil strainer 9, it becomes possible for the oil strainer 9 and the elastic body 10 to act as a dynamic damper. Further, the vibration of the oil strainer 9 functioning as the mass of the dynamic damper is damped by the lubricating oil.

[0016]

According to the vibration damping internal combustion engine of the first invention, not only the vibration generated in the bearing cap can be suppressed by the vibration damping plate, but also the vibration of the vibration damping plate can be suppressed by the lubricating oil. It also becomes possible to attenuate. According to the vibration damping internal combustion engine of the second aspect of the present invention, the oil damper and the elastic body constitute a dynamic damper, and the vibration generated in the bearing cap can be suppressed and damped.

[Brief description of drawings]

FIG. 1 is a front sectional view of an embodiment of the first invention.

FIG. 2 is a side sectional view of an embodiment of the first invention.

FIG. 3 is a perspective view of a damping plate.

FIG. 4 is a side sectional view of another embodiment of the first invention.

FIG. 5 is a side sectional view of an embodiment of the second invention.

[Explanation of symbols]

 1 ... Cylinder block 2 ... Bearing bulk 3 ... Bearing cap 41, 42 ... Bolt 5 ... Crank shaft 6 ... Oil pan 7 ... Lubricating oil 8 ... Damping plate 81 ... Mounting flange 82 ... Vertical part 83 ... Bending part 84 ... Horizontal plate 9 ... Oil strainer 10 ... Elastic body

Claims (2)

[Claims] 1. A cylinder block, a bearing bulk provided on the cylinder block, a bearing cap installed to face the bearing bulk and rotatably supporting a crankshaft, and a lubricant installed on a lower portion of the cylinder block. A vibration-damping internal combustion engine comprising: an oil pan to be stored; and a vibration damping plate attached to the lower end of the bearing cap and dipped in the lubricating oil stored in the oil pan. 2. The vibration-damping internal combustion engine according to claim 1, further comprising an oil strainer attached to a lower end of the bearing cap, and an elastic body arranged between the bearing cap and the oil strainer. .