JP2002310299A - Side rail for combined oil ring - Google Patents

Abstract

(57) [Summary] (Modified) [Problem] To prevent abnormal vibration and generate abnormal noise without increasing the consumption of lubricating oil during the internal combustion period and without the risk of the oil ring sticking in the piston ring groove. Provides a combination oil ring side rail that does not need to be used. SOLUTION: A synthetic resin film 3 is formed on at least one side surface of a combined oil ring side rail 2. By forming the synthetic resin film on the side rail side surface, vibration of the side rail is suppressed, and generation of sound can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a side rail for a combined oil ring mounted on a piston of an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, automobiles have been required to reduce CO ₂ emissions due to the problem of global warming, and it has become necessary to reduce the consumption of lubricating oil in addition to improving the fuel consumption rate. I have. Due to the demand for improving the fuel consumption rate and reducing the consumption of the lubricating oil, the lubricating oil used in the internal combustion engine tends to lower the viscosity of the lubricating oil.

In an internal combustion engine, an oil ring has a function of uniformly applying lubricating oil to a cylinder wall and a function of collecting excess lubricating oil. Without lubricating oil, the pressure ring and the piston immediately seize with the inner wall of the cylinder. If the amount of lubricating oil applied is large, and if it is not collected, the lubricating oil is carried to the combustion chamber and burned, so that the consumption of lubricating oil increases. Therefore, in order to reduce the consumption of lubricating oil, it is important to keep the amount of lubricating oil applied to the inner wall of the cylinder as thin as possible without burning the cylinder, piston and pressure ring, and to collect excess lubricating oil well. In addition, a device has been devised to increase the ring tension, which is the basis of the force by which the side rail presses the cylinder wall, as compared with the pressure ring.

For this reason, when a low-viscosity lubricating oil is used, the oil film easily breaks between the cylinder wall and the outer peripheral sliding surface of the side rail, the sliding friction force increases, and the outer peripheral side of the side rail is pulled to the side opposite to the side rail moving method. Then, at the moment when the outer peripheral side of the side rail returns to the original state, there is a phenomenon that abnormal vibration occurs when the side rail is in a free state not in contact with the spacer expander or the piston ring groove wall. In particular, this phenomenon occurs particularly when there is no familiarity between the inner wall of the cylinder and the outer sliding surface of the side rail, or at a low rotation speed such as idling rotation immediately after engine assembly and in the early stage of engine start, in other words, when it is difficult to form an oil film. It became clear that it was easy.

[0005] The abnormal vibration may propagate through the cylinder block of the internal combustion engine and be heard as sound outside the vehicle. In particular, in automobiles that require quietness, the generation of such noise has been required to be improved as it significantly lowers commercial value.

Conventionally, in order to suppress this vibration, the inclination angle of the side rail pressing piece of the spacer expander is reduced, and the side rail is pressed more strongly by the piston ring groove of the piston so as to always contact the piston ring groove. In order to reduce the clearance between the thickness of the three-piece combination oil ring in the axial direction of the piston and the width of the piston ring groove in the axial direction of the piston ring, a constant contact is taken.

In the former, the amount of lubrication consumed tends to increase because the pressing force on the inner wall of the cylinder decreases, and
The latter has a problem that the side rails are easily fixed in the piston grooves due to the influence of combustion products generated during operation of the internal combustion engine.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and does not increase the consumption of lubricating oil in an internal combustion engine, and the oil ring is fixed in a piston ring groove. It is an object of the present invention to provide a combined oil ring side rail that is free from fear of abnormal vibration and that does not generate abnormal noise.

[0009]

SUMMARY OF THE INVENTION A side rail for a combined oil ring according to the present invention has a synthetic resin film on at least one side thereof, and a synthetic resin film is formed on the side surface of the side rail. Thereby, the vibration of the side rail is suppressed, and generation of sound can be prevented.

It has been experimentally confirmed that the side rail vibrates largely in the axial direction when abnormal noise is generated. If this vibration can be suppressed, abnormal noise will be less likely to occur, so far, the ear angle of the spacer has been increased to increase the pressing force on the piston groove, or the space between the side rail and the ring groove By reducing the side clearance, the degree of freedom in the axial direction of the rail was restrained to suppress abnormal noise. However, these methods have caused the above problems.

Therefore, the present inventor has noticed that the vibration phenomenon is a divergence phenomenon, and has noticed that even if the vibration occurs, the steady vibration cannot be achieved if the energy can be absorbed quickly. That is, the present invention pays attention to the vibration damping performance of the side rail, and adopts a side rail structure in which the side rail vibration is quickly reduced even if the side rail vibrates.

When the side rail collides with the piston groove due to the side rail vibration, if the coefficient of restitution is small, the vibration energy of the side rail is quickly absorbed by the piston, and the vibration does not continue. In other words, it will not be heard as abnormal noise. The material having a low coefficient of restitution is generally a soft material having a low Young's modulus, and in the present invention, by forming a synthetic resin film on the side rail side surface, the coefficient of restitution when the side rail collides with the piston groove is reduced. Reduced. Thereby, even if the side rail starts to vibrate, its energy is quickly absorbed and does not shift to steady vibration.

The reason why the thickness of the synthetic resin film is 1 to 10 μm is as follows.
If the thickness is less than 1 μm, the film is too thin to effectively absorb energy. The reason for setting the thickness to 10 μm or less is that when the synthetic resin film is worn, the side clearance becomes large, which may cause an increase in oil consumption. Because. The synthetic resin film is formed by spray coating. The temperature of the synthetic resin film near the oil ring is 120 to 150 ° C.
And lower than the pressure ring, any resin can be used as long as it is a resin having a softening point of 150 ° C. or higher, but from the viewpoint of ease of film formation, marketability, etc.
PTFE, polyimide, polyimide amide, vinyl chloride, and polyester are desirable. In particular, since the film containing a solid lubricant (20 to 50% by weight) has a high lubricating property, it also has a function of suppressing abrasion of the synthetic resin film.

[0014]

1 and 2 show an embodiment of the present invention. FIG. 1 shows a combination of a radial expander spacer expander 1 and side rails 2 and 2 having a synthetic resin film layer 3 formed on both sides by spray coating. FIG. 2 shows a combination of an axial corrugated spacer expander 4 and side rails 2 and 2 having synthetic resin films 3 formed on both side surfaces.

In order to confirm the noise reduction effect when the synthetic resin film 3 was formed on the side surfaces of the side rails 2 and 2, side rails having specifications shown in Table 1 were prototyped. The size of the side rail body is 89 mm in diameter × 0.45 mm in thickness × 2.5 mm in width, the material is 17Cr martensitic stainless steel, and a nitrided layer is formed on the surface by gas nitriding.

A unit test apparatus as shown in FIG. 3 was used to confirm the sound reduction effect. The device has a cylinder 5 and a shaft 6 that moves up and down at the center of the cylinder 5. A piston 7 is mounted on the shaft 6,
The oil ring 9 is attached to the piston groove 8 of the piston 7 for evaluation. Since abnormal noise is generated when the shaft moves up and down, the level of the abnormal noise was measured by the sound level meter 10 to confirm the effect of reducing the generation of the abnormal noise.

The results are shown in Table 1. The effect was confirmed for both the polyimide amide and PTFE films. Although a slight effect can be confirmed even when the film thickness is 0.5 μm, considering the man-hours required for the production, it is not a good idea but 1
μm or more is required. The content of the solid lubricant is not related to the effect of preventing generation of abnormal noise, but may be contained because it has an effect on the durability of the film.

[0018]

[Table 1]

[0019]

According to the present invention, there is no concern about deterioration of lubricating oil consumption performance and no fear of sticking of the combined oil ring in the piston ring groove, and rail vibration does not occur even in the initial stage of assembling the internal combustion engine. Rings can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a three-piece oil ring using a radial corrugated spacer expander according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a three-piece oil ring using an axial corrugated spacer expander according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a unit test apparatus.

[Explanation of symbols]

 1,4 Spacer expander 2 Side rail 3 Synthetic resin film

Claims (4)

[Claims] 1. A side rail for a combined oil ring, wherein the side rail has a synthetic resin film on at least one side surface of the side rail. 2. The synthetic resin film has a thickness of 1 to 10 μm.
The side rail according to claim 1, wherein: 3. The synthetic resin film is made of PTFE, polyimide,
3. The side rail according to claim 1, wherein the side rail is at least one selected from polyimideamide, vinyl chloride, and polyester. 4. The side rail according to claim 1, wherein the synthetic resin film contains a solid lubricant such as molybdenum disulfide, boron nitride, graphite and the like.