JPH0122920Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a combination oil ring consisting of a steel expander and a resin oil ring used in a piston of a reciprocating internal combustion engine.

Recent engines tend to have higher rotation speeds and higher outputs, and accordingly, the requirements for piston rings used in engines are becoming stricter. In other words, the oil ring, which is a sliding part, must be able to withstand sliding with the cylinder for a long period of time even under high load and high rotation operating conditions, and must be able to maintain an appropriate amount of oil at all times between it and the cylinder's inner peripheral surface. Must be. In other words, there is a need for a high-performance oil ring that can reduce oil consumption and always maintain the minimum necessary oil film between the cylinder and the inner circumferential surface.

Conventional technology Instead of conventional cast iron cutter type oil rings and expander-equipped oil rings with plate type expanders or coil springs attached to the inner circumference,
Recently, a steel combination oil ring that combines two side rails and one spacer expander has been developed and put into practical use in order to provide even higher functionality for high-speed engines. By the way, during engine operation, the cylinder may undergo thermal deformation and take on an elliptical shape or a locally irregular shape. Although conventional oil rings can follow such cylinder deformations to some extent, they cannot follow large deformations or irregular deformations, resulting in an increase in oil consumption during operation. In order to prevent this, that is, to reduce the thickness of the oil film remaining on the cylinder wall and reduce oil consumption, it is necessary to increase the surface pressure of the oil ring and improve its followability to the cylinder. be. However, since conventional oil rings made of iron-based materials have high rigidity, the surface pressure (pressing force) of the oil ring must be considerably high in order to follow the thermally deformed cylinder wall. However, if the surface pressure is increased, the wear on the outer circumferential surface of the oil ring is likely to accelerate, leading to a lack of lubricating oil between the inner circumferential surface of the cylinder and the oil ring, causing so-called oil film failure, and causing scuffing. There is a problem with becoming.
Therefore, there are limits to solutions that rely on increasing the surface pressure.

Apart from this, in the case of a steel combination oil ring, it is also possible to improve the followability to the cylinder by making the side rails thinner.
In that case, the strength is likely to be insufficient, which may cause damage to the oil ring during operation, so it cannot be said to be a preferable solution.

Purpose of the invention The purpose of the present invention is to solve this problem by creating a resin ring that is divided into two in the axial direction and an expander that stretches it outward from the inner circumferential surface.The purpose of the invention is to reduce oil consumption and improve durability. It is an object of the present invention to provide a certain resin combination oil ring.

Structure of the invention In order to achieve the above object, the resin combination oil ring according to the invention is composed of a pair of ring halves made of heat-resistant and wear-resistant polymer resin, which are divided into upper and lower halves and have the same shape. It includes an oil ring and a steel expander that presses and tensions the oil ring in the radial and axial directions. Each ring half of the oil ring has an inner tapered surface that forms a roughly V-shaped expander accommodating section when both ring halves are overlapped; A plurality of concave grooves are provided between the opposing surfaces to form oil holes that communicate the outer circumferential side and the inner circumferential side of the oil ring. The expander is formed as a gapped annular plate having a corresponding generally V-shaped cross section for surface contact with the generally V-shaped expander receiving portion of the oil ring.

Functions and Effects of the Invention The resin oil ring of the invention has a lower elastic modulus and superior flexibility compared to conventionally used cast iron oil rings or steel combination oil rings, so it is less susceptible to thermal deformation. It is also possible to sufficiently follow the cylinder, thereby preventing an increase in oil consumption during operation. Also,
Since the resin oil ring of this invention has a low coefficient of friction, it can reduce friction loss between the cylinder and the oil ring, leading to improved fuel efficiency. Furthermore, since the resin oil ring of this invention is a two-part type that is free from each other, it has better followability and is less likely to be hit hard locally, making it much less likely to cause scuffing than conventional oil rings. Become.

Embodiments Hereinafter, embodiments of the combination oil ring of the present invention will be described based on the drawings.

In Figures 1, 2, and 3, a pair of ring halves 1 and 1' having the same shape are made of a resin such as polyimide, polyamideimide, or tetrafluoroethylene, which is a polymeric material with excellent heat resistance and wear resistance. It is constructed in the form of a ring with an opening. These two ring halves 1, 1' are mounted in the oil ring groove 12 of the piston 10 so as to be stacked vertically in the axial direction so that their inner circumferential surfaces form a V-shape, as will be described later.

Each ring half body 1, 1' has an outer circumferential sliding surface 3, 3' on its outer circumferential side that slides against the cylinder inner circumferential wall 15, and has a tapered surface 5, 5' on its inner circumferential side.
Both ring half parts 1, 1' constitute an oil ring when overlapped in the oil ring groove 12 as shown in the figure, and have a substantially V-shaped shape formed by tapered surfaces 5, 5' on the inner circumferential side thereof. Expander housing section 17
is formed. Further, a plurality of concave grooves 9, 9' are preferably arranged at equal intervals in the circumferential direction on the overlapping surfaces of each ring half body 1, 1', so that both ring half bodies 1, 1' are overlapped. When matched, an oil hole 21 penetrating from the outer circumferential side of the ring to the inner circumferential side is formed between the opposing surfaces. As is well known, the oil hole 21 guides the oil adhering to the cylinder inner circumferential surface 15 from being scraped off by the outer circumferential sliding surfaces 3 and 3' of the oil ring to the inner circumferential side of the oil ring through the oil hole 21. This is for returning the oil to an oil pan (not shown) through the oil circulation hole 11. The upper and lower side surfaces 7, 7' of the ring halves 1, 1' form flat sealing surfaces that are in close contact with the side walls of the oil ring groove 12.

The steel expander 23 has a substantially V-shaped cross section corresponding to the expander accommodating portion 17, and is formed as an annular plate having an abutment. An oil window 27 corresponding to the oil hole 21 is provided in the center of the expander 23 in the circumferential direction.

Since the expander 23 has a V-shaped cross section and tension acts in the vertical and circumferential directions, the ring halves 1 and 1' mounted in the oil ring groove 12 are pressed against the cylinder inner circumferential surface 15, and at the same time the upper and lower side surfaces are 7, 7' can be pressed against the upper and lower side walls of the oil ring groove 12. Therefore, the oil scrubbing function between the oil ring outer circumferential sliding surfaces 3, 3' and the cylinder inner circumferential surface 15 and the sealing function between the oil ring upper and lower side surfaces 7, 7' and the side walls of the corresponding oil ring grooves 12 are achieved. can be achieved at the same time. As a result, not only can oil consumption be reduced, but the oil ring does not move axially within the oil ring groove 12 during operation, which prevents so-called oil leakage that occurs during high vacuum boost. It will also be possible to do so.

Preferably, the ring halves 1, 1' have a thickness such that when they are overlapped and stretched by the expander 23, there is a slight gap 28 between them. In other words, due to the presence of this gap 28, the two ring halves 1, 1' are completely independent of each other, so that one cannot be rubbed or moved by the other. Also, when the ring halves 1, 1' are assembled into the ring groove 12, the work is easier if there is a gap 28. In this way, the ring halves 1 and 1' are divided into two in the axial direction X-X, and can be used against cylinders whose roundness deteriorates because the upper and lower ring halves move separately. It has good followability and also contributes to improving the airtightness of the sliding surface with the cylinder and the contact surface with the side wall of the oil ring groove 12. In addition, resin rings have a smaller elastic modulus than metals and are superior in flexibility, so the surface pressure on the inner peripheral surface of the cylinder and the side wall of the oil ring groove 12 does not require a large value, even with low surface pressure. Improves followability.

In addition, by making the expander 23 an annular plate with a substantially V-shaped cross section that conforms to the shape of the expander accommodating portion 17 of the oil ring, the contact area between the two is increased, so that the expander can be attached to each half of the ring. It is possible to effectively apply a pressing force to each half of the ring while preventing it from partially biting into the inner circumferential surface of the ring.

Conventional cast iron oil rings require extremely complicated manufacturing work due to their complex cross-sectional shapes, but the resin oil ring of this invention
It can be easily manufactured by compression molding or injection molding.

In addition, according to compression molding or injection molding, the concave grooves 9, 9' (i.e., oil holes 21) of each ring half are formed.
can be molded at the same time, eliminating the need for mechanical drilling, leading to significant cost reductions.

Note that the ring halves 1 and 1' are machines with the same shape stacked on top of each other in the axial direction, so the second
The ring halves can be obtained with one and the same mold forming the shape shown in the figures.

Note that 29 shown in FIG. 3 is a notch formed at the edge of the expander 23, which serves to increase the flexibility of the expander 23.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a resin combination oil ring according to the present invention inserted into an oil ring groove of a piston, and Fig. 2 is a partial perspective view of a resin oil ring half according to the present invention. FIG. 3 is a perspective view of a part of the expander according to the present invention. 1, 1'...Resin oil ring half part, 5,
5'...Tapered surface, 9,9'...Concave groove, 17...Expander housing part, 21...Oil hole, 23...
Expander.

Claims (1)

[Scope of utility model registration request] An oil ring consisting of a pair of heat-resistant and wear-resistant polymer resin ring halves divided into upper and lower halves of the same shape, and a steel extractor that presses and tensions the oil ring in the radial and axial directions. Each ring half of the oil ring has an inner circumferential tapered surface that forms a substantially V-shaped expander accommodating portion when the two ring halves are superimposed, and a The expander has a plurality of concave grooves that form oil holes that communicate between the outer circumferential side and the inner circumferential side of the oil ring between the opposing surfaces when the two parts are superposed, and the expander is an abbreviation for oil ring. Approximately V corresponding to surface contact with the V-shaped expander housing part
A resin combination oil ring characterized in that it is formed as an annular plate with an abutment having a letter-shaped cross section.