JPH08261326A - Oil ring with expander - Google Patents

Abstract

PURPOSE: To provide a light-weight oil ring which is superior in oil scraping performance and has durability by arranging a plate expander which contacts with internal faces of upper/lower rings, in the insides of the upper/lower rings which is convex in its internal/outer circumferential faces and symmetrical in its top/bottom in section. CONSTITUTION: Oil ring which are made of steel are convex in their internal/ outer circumferential fades and symmetrical in their top/bottom in section, the upper ring 2 and lower ring 3 are vertically arranged, and a U-sectional plate expander 5 is sandwiched between the intermediate insides of both rings 2, 3. Both rings 2, 3 are pressed outward against the inside wall 71 of a cylinder 7 by the plate expander 5 and at the same time pressed vertically, because the internal faces are convex and inclined, so that a side clearance toward a ring groove 61 of a piston 6 is eliminated. This constitution can improve sealing performance on the top/bottom faces of the ring groove 61 and save oil consumption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil ring with an expander for scraping off excess oil from the inner wall of a cylinder in an internal combustion engine such as a diesel engine or a gasoline engine.

[0002]

2. Description of the Related Art In an internal combustion engine such as a diesel engine or a gasoline engine, a pressure piston ring (also simply referred to as a pressure ring) and an oil ring are mounted in a piston ring groove provided on the outer circumference of a piston, and the combustion gas is mainly generated by the former. It is usual to prevent the leakage of the oil and to scrape off the excess lubricating oil adhering to the inner wall of the cylinder to prevent the lubricating oil from flowing into the combustion chamber and burning. In addition to the above, the function of the piston ring is required to have many functions such as a heat transfer function of transferring the heat of combustion to the outside to remove it, and a bearing function of smoothing the reciprocating motion of the piston.

Conventionally, as these oil rings, an oil ring with a coil expander and an oil ring with a plate expander, which will be described later, a combination oil composed of two upper and lower side rails and a spacer expander inserted between them. Rings and the like are widely known. FIG. 2 is a perspective view showing an oil ring main body of a general oil ring with a coil expander excluding the coil expander, and FIG. 3 is shown in FIG. 2 which is described as a conventional example in Japanese Utility Model Laid-Open No. 54-53108. FIG. 2 is an exploded perspective view showing only the essential part of an oil ring similar to that shown in FIG. 1, where (a) shows a part of the oil ring body, (b) shows a part of the coil expander, 1 is the oil ring body, and 11 is The upper seal portion, 12 is a lower seal portion, 13 is a connecting portion connecting the upper seal portion 11 and the lower seal portion 12, 14 is an oil hole, and 4 is a coil expander.

The oil ring body 1 has an upper seal portion.
11 is a cast iron ring having a substantially I-shaped cross section in which a lower seal portion 12 and a lower seal portion 12 are connected to each other, and an abutment 15 is provided for expanding the inner diameter and mounting it in a ring groove provided in a piston. is there. Excess oil adhering to the inner wall of the cylinder as the piston reciprocates causes the upper and lower seal parts 1
It is scraped off by the outer peripheral sliding surfaces 1 and 12.

A groove for receiving the scraped oil is formed on the outer peripheral surface of the connecting portion 13, and an oil hole 14 is provided in the connecting portion 13 for returning the oil from the inside of the piston to the oil pan. On the other hand, the coil expander 4 is mounted on the inner surface of the connecting portion 13 to push the oil ring body 1 outward. FIG. 4 is a cross-sectional view of a main part showing a usage state of the oil ring, wherein 6 is a piston and 7 is a cylinder. The oil ring is a ring groove provided on the piston 6.
The coil expander 4 presses against the inner wall 71 of the outer cylinder 7, which is mounted on the inner wall 71 of the cylinder 7.

On the other hand, Japanese Utility Model Publication No. 47-31927 discloses a plate expander in which an elongated steel strip is processed into a ring shape with respect to the coil expander 4. This will be described with reference to FIG. FIG. 5A shows a part of the oil ring,
(B) is a perspective view showing a part of the plate expander,
5 is a plate expander and 51 is a slot.

The plate expander 5 is provided with slots 51 that do not penetrate from the both sides of a long and thin steel strip alternately to the opposite side, and has a cross section bent into a V-shape and the whole is formed on the inner peripheral surface of the oil ring body 1. It has a ring shape along it. The cross section may be bent into a U shape or a semicircular shape. Similar to the coil expander 4, it works to push the oil ring body 1 outward and push it against the inner wall 71 of the cylinder 7. However, since the dimension in the radial direction is smaller than that of the coil expander 4, a ring provided on the piston 6 is provided. The groove 61 also has an advantage that it may be shallow.

[0008] As still another conventional example, the actual exploitation 54-53108
FIG. 6 shows an oil ring according to the device described in the publication. The figure is a cross-sectional view of the main part showing the usage state of the oil ring. The oil ring is composed of two rings, an upper ring 2 and a lower ring 3, and a coil expander 4 arranged inside thereof.
It consists of three points. In the case where the oil ring main body 1 shown in FIGS. 2 to 4 and FIG. 5 is integrally formed by connecting the upper seal portion 11 and the lower seal portion 12 with the connecting portion 13, the assembly and the thermal expansion are prevented. From both sides, between the upper and lower surfaces of the oil ring body 1 and the ring groove 61 on the piston side,
The side clearance f shown in FIG. 4 is required, and this clearance serves as a passageway for oil to consume a large amount of oil, and since the upper and lower seal portions 11 and 12 move integrally, the followability with respect to the cylinder inner wall 71 is improved. There is a problem that it is bad. If the material of the oil ring is cast iron, the oil hole
Since 14 is usually milled, many holes cannot be formed unnecessarily, and if a part of the oil hole 14 is blocked by the coil expander 4 or the plate expander 5 to some extent, the oil will not pass properly. There is also a problem that the effect of oil scraping decreases. In addition, the cast iron oil ring has a low mechanical strength, and therefore has a large cross-sectional dimension, which has a poorer followability with respect to the operation of the piston.
It is also not preferable for reducing the weight of the engine.

According to Japanese Examined Patent Publication No. 29979/1990, a rod-shaped, linear or strip-shaped steel material is drawn or rolled into a material having a substantially I-shaped cross section, and a large number of oil holes are formed in the web portion by punching. To produce an oil ring. That is, by making the oil ring main body of the I-shaped section made of steel, the connecting portion is made thin, and the weight is reduced, the elastic modulus is improved, and the oil scraping performance is improved by increasing the number of oil holes. Although the advantages are recognized, the problems regarding the side clearance have not been resolved.

On the other hand, in the structure shown in FIG. 6 in which the upper and lower seal portions are separated to form a three-point structure, the coil expander 4 is contacted with the upper ring 2 and the lower ring 3 on the inner peripheral sloped surface 21,
Since the upper ring 2 and the lower ring 3 are opened in the up-down direction by the tension of the coil expander 4 by performing the process at 31, there is an advantage that the side clearance is eliminated. However, the contact between the coil expander 4 and the upper ring 2 and the lower ring 3 is point-like in the cross section, and actually linear, and the contact area is extremely small, so that the wear is fast,
Since the compression ratio is high, the ring tension also has to be designed high, so there is a problem in durability for diesel engines.

Further, as a contact surface with the coil expander 4, a slope 21 is provided on the inner peripheral side of the upper ring 2 and the lower ring 3,
Since 31 is formed, the upper ring 2 and the lower ring 3 are vertically asymmetrical as a single body respectively, and the following problems occur. 1) The oil ring is designed not to be a perfect circle in the free state, but to be a perfect circle only when the abutment 15 is closed, that is, when it is mounted in the cylinder. For this reason, when the abutment of a ring with an asymmetric cross section is closed, the ring surface keeps a flat surface and is deformed in the out-of-plane direction, that is, wavy or twisted (hereinafter, this phenomenon is referred to as "surface buckling"). That). Therefore, a local gap is generated in the up-down direction between the piston 6 and the ring groove 61, and as with the side clearance f in FIG. 2) The upper ring 2 and the lower ring 3 are the same parts, but the directions are opposite, so care must be taken when assembling.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and to realize an oil ring that is lightweight, has excellent oil scraping performance, and is durable.

[0013]

DISCLOSURE OF THE INVENTION According to the present invention, a plate which is in contact with the inner peripheral surfaces of the upper ring and the lower ring is provided inside the upper ring and the lower ring, both inner and outer peripheral surfaces of which have a middle height and a vertically symmetrical cross-sectional shape. An oil ring with an expander in which an expander is arranged.

[0014]

[Operation] The oil ring in the present invention is composed of three points, an upper ring, a lower ring and a plate expander. Since the upper ring and the lower ring are not fixed by the web, they have good followability with the inner wall of the cylinder. No side clearance issues. Furthermore, since the upper ring and the lower ring are vertically symmetrical in cross section, surface buckling does not occur in the use state, and the assembly work is easy when the upper ring and the lower ring are the same part.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of an essential part of the oil ring in use, and the same reference numerals are used for the same parts as before.
In this oil ring, an upper ring 2 and a lower ring 3 made of steel and having a vertically-symmetrical cross-sectional shape and having a middle height on both the inner and outer peripheral surfaces are vertically arranged, and a plate is provided inside the middle of the upper ring 2 and the lower ring 3. The expander 5 is sandwiched in between. The cross-sectional shapes of the upper ring 2 and the lower ring 3 will be described in more detail. First, the inner peripheral surface is vertically symmetrical and is composed of two straight lines of medium height (conical surface as a surface), and the outer peripheral surface that is a sliding portion is the same. The upper and lower central parts are protruding, and the outer edges of the protruding parts are extremely sharp and have a width that does not cause severe wear. .

Therefore, the upper ring 2 and the lower ring 3
Is pressed outward by the plate expander 5, that is, on the inner wall 71 of the cylinder 7, and at the same time, it is also pressed vertically due to the inclined surface having a medium height. The side clearance is eliminated and the upper and lower surfaces of the ring groove 61 are well sealed, which can reduce the oil consumption.

Since the cross section of the plate expander 5 has a "V" shape corresponding to the inner peripheral inclined surfaces of the upper and lower rings 2 and 3, it is in contact with a wide area and therefore wear is small. Furthermore, since the upper ring 2 and the lower ring 3 are separate rings, they move independently of each other and have good followability with the inner wall of the cylinder. Further, since it is not necessary to provide an oil hole, a problem such as clogging does not occur.

The upper ring 2 and the lower ring 3 have the same shape, and their cross sections are vertically symmetrical. Therefore, there is no problem of buckling, and since two identical parts are used, there is not only a mass production effect, but also it is possible to assemble without considering the vertical direction. is there. The oil ring body is not limited to steel, and may be made of cast iron, a metal other than that, heat-resistant synthetic resin, or the like.

[0019]

The oil ring of the present invention has a three-point construction, and since the upper ring and the lower ring have vertically symmetrical cross sections, there is no gap between the upper and lower surfaces of the ring groove when mounted in the ring groove of the piston, and the upper ring is Since the lower ring and the lower ring can be moved independently, they have good oil scraping performance, and because they have a slim cross-section, they are lightweight and have a long life due to less wear, which reduces oil consumption. It also has the excellent effect of achieving a lightweight engine.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a usage state of an oil ring according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a conventional general oil ring.

FIG. 3 is a partial perspective view showing an example of a conventional general oil ring.

FIG. 4 is a partial cross-sectional view showing a conventional general oil ring in use.

FIG. 5 is a partial perspective view showing another conventional oil ring.

FIG. 6 is a partial cross-sectional view showing a usage state of another conventional oil ring.

[Explanation of symbols]

 1 Oil ring body 2 Upper ring 3 Lower ring 4 Coil expander 5 Plate expander 6 Piston 7 Cylinder 11 Upper seal part 12 Lower seal part 13 Connecting part 14 Oil hole 15 Fitting 21 Slope 31 Slope 61 Ring groove 71 Inner wall

Claims (1)

[Claims] 1. The inner circumferences of the upper ring (2) and the lower ring (3) are inside the upper ring (2) and the lower ring (3), which have a vertically-symmetrical cross-sectional shape on both the inner and outer peripheral surfaces. An oil ring with an expander in which a plate expander (5) in contact with the surface is arranged.