JPH10274331A - Piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sufficient air tightness holding function and a sufficient lubricating oil adjusting function by combining two of a first and a second rings, which are respectively formed by forming a steel wire into an annular shape having an abutment part at a part thereof. SOLUTION: A piston ring R is formed of a first ring 1, which is formed by forming a steel wire having a L-shaped cross section into an annular shape having a stage part (g) in the peripheral side thereof, and a second ring 2, which is formed by forming a steel wire into an annular shape having an outer diameter larger than the outer diameter of the first ring. When both the rings 1, 2 are fitted in a ring groove G of a piston P in the condition that abutment parts thereof are displaced from each other so that they are not overlapped with each other, the inner peripheral surface of the first ring 1 pushes a bottom surface of the ring groove G with elasticity thereof. The outer peripheral surface of the second ring 2 pushes the inner peripheral wall surface of a cylinder C with elasticity thereof for installation. With this structure, generation of a passage of gas leak is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a piston ring used for a piston of an internal heat engine such as an automobile engine and a motorcycle engine.

[0002]

2. Description of the Related Art A piston ring of this kind is mounted in a ring groove of a piston of an internal heat engine and leaks high-temperature and high-pressure gas generated in a combustion chamber when the piston ring slides on the inner peripheral wall surface of the cylinder together with the piston. Is used to prevent
In recent years, piston rings have been required to further improve the following functions in accordance with higher performance of engines. (1) Maintaining airtightness Maintaining airtightness between the piston and the cylinder and suppressing gas leakage into the crank chamber, mainly for improving thermal efficiency. (2) Lubricating oil adjustment function In order to smoothly slide at high speed on the inner peripheral wall of the cylinder, lubricating oil is constantly supplied, and an oil film is held between the piston ring and the piston, and the performance of the engine is hindered. Lubricating oil must not leak to the combustion chamber more than necessary to prevent the generation of carbon sludge. However, since the conventional piston ring is formed by bending a flat steel wire of a required length into an annular shape having a cut part called an "aperture", high-pressure gas leaks to the low-pressure side from the aforesaid aperture. In addition, there is a problem that the oil consumption increases due to the oil leaking into the combustion chamber, and the functions (1) and (2) cannot be satisfied. Is the actual situation.

Therefore, recently, a piston ring having an improved abutment structure as shown in FIG. 3 has been proposed (for example, Japanese Utility Model Laid-Open No. 4-119665, Japanese Patent Laid-Open No. 8-68).
466). This piston ring 11 is shown in FIG.
As shown in (a), at one end of the abutment 14 part,
A convex portion 12 having a triangular cross section is formed, and a concave portion 13 corresponding to the convex portion is formed at the other end portion, thereby improving the airtightness of the abutting portion.

[0004]

However, when the piston ring 11 is fitted in the ring groove of the piston P and mounted on a cylinder as shown in FIG. A leakage path α and a gas leakage path β due to a fitting gap between the piston ring and the ring groove are generated. For this reason, in the piston ring 11, the high-temperature, high-pressure gas on the engine combustion chamber side passes through the gas leakage passages α, β
And leaks to the crankcase side, thereby deteriorating the function of maintaining airtightness, or leaking lubricating oil, deteriorating the function of adjusting lubricating oil, and increasing oil consumption.

[0005] The piston ring 11 has a projection 12
Since the thickness of the recess 13 becomes thinner and the strength of the abutment portion decreases, breakage or breakage is likely to occur due to vertical movement of the piston or frictional force with the inner wall of the silling. In particular, the protrusion 12
Since the cross-sectional area is smaller than that of the recess 13 and the strength of the pointed thin portion having a triangular cross-section is particularly weak, stress concentration is likely to occur, and the incidence of breakage and breakage is high. In addition, the projections and depressions are formed by cutting or grinding, but there is a problem that the projections and depressions are likely to be damaged during processing, or to be damaged or deformed during cylinder mounting or transportation. There is.

An object of the present invention is to solve the above-mentioned problems of the prior art piston ring, and to provide a piston ring which has a sufficient airtight maintenance function and a lubricating oil adjusting function and is free from breakage or breakage. I do.

[0007]

In order to solve the above-mentioned problems, a piston ring according to the present invention comprises two rings, a first ring and a second ring, each of which is formed by forming a steel wire into an annular shape having a joint at a part thereof. Are combined. That is, the piston ring of the present invention is provided with a step portion over the entire outer peripheral side of the first ring, the second ring can be loosely fitted to the step portion, and the outer diameter of the second ring is set to the first ring. The outer diameter of the second ring is slightly larger than the outer diameter so that the outer peripheral surface of the second ring contacts the inner wall surface of the cylinder. With the above configuration, the piston ring of the present invention has an airtight maintaining function and a lubricating oil by closing the joint of the first ring with the second ring and closing the joint of the second ring with the first ring. The adjustment function can be sufficiently exhibited. Further, since the cross-sectional shapes of the first and second rings are uniform over the length, there is no partial strength deterioration and no stress concentration occurs.

Further, when the piston with the piston ring mounted thereon is fitted into the cylinder, the inner peripheral surface of the first ring and the outer peripheral surface of the second ring use the elasticity of the ring material to make use of the elasticity of the ring material. By elastically pressing the inner wall surfaces of the cylinders, respectively, the airtightness maintaining function can be further exhibited, the cushioning property is enhanced, and a large load and friction are not applied to the piston ring.

Further, if positioning means is provided on at least one of the rings so that the abutment between the first ring and the second ring does not overlap, vibration or friction during use may cause
Causing a relative displacement between the first ring and the second ring,
The abutment of both rings can be prevented from overlapping.

[0010] Further, by subjecting at least the outer peripheral surface of the second ring, which is to be in contact with the cylinder, with a surface treatment,
It is possible to improve the wear resistance and reduce the sliding friction to increase the speed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a plan view of a piston ring R according to the present invention. This piston ring R is formed by forming a steel wire having a substantially L-shaped cross section into an annular shape having a step portion g on the outer peripheral side. From a curved first ring 1 and an annularly curved second ring 2 having an inner diameter capable of loosely fitting the steel wire to the step g and an outer diameter larger than the outer diameter of the first ring. Become. In the figure, reference numerals 3 and 4 denote openings. FIG. 1B is a cross-sectional view showing a use state of the piston ring R according to the present invention.
In this figure, P is a piston, C is a cylinder, and each ring is fitted into the ring groove G of the piston P so that the joint 3 of the first ring 1 and the joint 4 of the second ring 2 do not overlap each other. When set, the inner peripheral surface of the first ring contacts the bottom surface of the step g of the first ring 1 and the outer peripheral surface of the second ring 2 contacts the inner wall surface of the cylinder C due to the elasticity of each ring. Also, a small gap is formed between the outer peripheral surface of the step portion g of the first ring 1 and the inner peripheral surface of the second ring 2. Although the second ring 2 is arranged below the first ring 1 in FIG. 1B, the second ring 2 can be turned upside down. Further, although the second ring uses a steel wire having a rectangular cross section, a rectangular steel wire having an arcuate surface on the outer peripheral side may be used to reduce the contact area with the inner peripheral wall surface of the cylinder.

FIGS. 2A and 2B show different embodiments. The piston ring R is provided with a projection 5 projecting downward from a part of the first ring 1 and both rings are set. Sometimes, the protrusion 5 is fitted into the abutment 4 of the second ring, so that the relative position between the two rings can be kept constant. By the way, the projections 5 are provided by pressing, but may be provided by other means (for example, metal fusion), and may be provided on a part of the second ring or on both rings instead of the first ring. It is possible. The surface treatment applied to at least the outer peripheral surface of the second ring 2 that is to be in contact with the cylinder is preferably performed by hard chrome plating, nitriding, satin finish, or the like, which imparts abrasion resistance and improves sliding characteristics. is there.

[0013]

An embodiment of the present invention will be described. Thickness 2
mm, width 3.8 mm, step depth 1.2 mm, step width 2.
A 5 mm steel wire having a substantially L-shaped cross section is formed into an annular curve so that the step portion is located on the outside, and the first ring 1 partially having an abutment is formed. Further, a flat steel wire having a rectangular cross section having a thickness of 1.2 mm and a width of 2.8 mm is formed into an annular shape by bending into a circular shape, thereby forming a second ring 2 having an abutment in a part. The second ring 2 has an inner diameter large enough to be loosely fitted to the step of the first ring and an outer diameter larger than the outer diameter of the first ring.

When the two rings 1 and 2 are displaced so that their abutments 3 and 4 do not overlap with each other and fitted into the ring groove G of the piston P as shown in FIG. 1 has an inner peripheral surface which presses the bottom surface of the ring groove G (in the axial direction of the piston) by elasticity, and a second ring 2
Is mounted with its outer peripheral surface pressed against the inner peripheral wall surface of the cylinder C by elasticity. Therefore, when the piston ring of the present invention is used, the gas leak passages α and β existing in the conventional piston ring shown in FIG. 3 are eliminated.

Next, the piston ring of the embodiment and the conventional piston ring shown in FIG. 3 were respectively attached to the piston of the test engine, and a ring characteristic comparison test was performed.
Table 1 shows the results.

[0016]

[Table 1]

In Table 1, the airtightness is calculated from the gas pressure in the combustion chamber, and is expressed by an index with the conventional piston ring being 100, and the higher the index, the better the airtightness. The index using the piston ring of the present invention was 115, and it was confirmed that the airtightness was improved.

The lubricating oil consumption indicates a function of maintaining and adjusting the lubricating oil. The lubricating oil consumption after the engine has been operated for a certain period of time is represented by an index with the conventional piston ring as 100, and the smaller the index, the smaller the index. Indicates that the lubricating oil holding adjustment function is good. In the case of using the piston ring of the present invention, it was confirmed that the consumption of the lubricating oil was reduced to an index of 75, and the lubricating oil holding adjustment function was improved.

Further, when the state of the abutment after long-time operation was examined, there was no noticeably bad portion in the present invention, but in the conventional piston ring, the deficiency of the projection was considerably advanced.

[0020]

Since the present invention has the above-mentioned structure, there is no gas leakage passage, the airtightness maintenance function is remarkably excellent, the blow-through of combustion gas is greatly reduced, and the combustion efficiency is improved.
Further, since the lubricating oil adjusting function is excellent, the amount of oil film on the sliding surface of the cylinder can be appropriately maintained, and the generation of carbon sludge due to the combustion of the lubricating oil can be suppressed. Further, since there is no pointed thin portion unlike the conventional piston ring and the structure is of a united type, even if the engine rotates at high speed, loss of the abutment can be prevented. When a surface treatment is performed on at least the outer peripheral surface of the second ring that comes into contact with the inner wall surface of the cylinder, wear resistance and sliding characteristics can be improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a piston ring of the present invention,
(A) is a plan view and (B) is an enlarged sectional view of a main part showing a use state.

FIG. 2 shows another embodiment of the present invention, wherein (a) is a plan view,
(B) is a partially enlarged view of (A) viewed from the A side.

3A and 3B show a conventional piston ring, wherein FIG. 3A is a perspective view of a main part, and FIG. 3B is an enlarged sectional view of a main part showing the same use state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... First ring 2 ... Second ring 3 ... Joint of first ring 4 ... Joint of second ring 5 ... Projection R ... Piston ring g ... Step Department

Claims (4)

[Claims] An inner diameter capable of loosely fitting a first wire and a second ring in which a steel wire is partially curved and formed into an annular shape having an opening at a part thereof, wherein the second ring is loosely fitted to a step provided on an outer peripheral side of the first ring. A piston ring having an outer diameter larger than the outer diameter of the first ring. 2. The piston according to claim 1, wherein the inner peripheral surface of the first ring can be mounted so as to elastically press the bottom surface of the ring groove of the piston, and the outer peripheral surface of the second ring can press the inner wall surface of the cylinder. ring. 3. The piston ring according to claim 1, wherein a positioning means is provided on at least one of the rings so that the abutments of the first ring and the second ring do not overlap with each other. 4. The pitton ring according to claim 1, wherein at least a contact surface of the second ring with the cylinder is subjected to a surface treatment.