WO2009104031A2

WO2009104031A2 - Split sealing ring for pistons

Info

Publication number: WO2009104031A2
Application number: PCT/HU2009/000019
Authority: WO
Inventors: László WILHEIM
Original assignee: Wilheim Laszlo
Priority date: 2008-02-19
Filing date: 2009-02-19
Publication date: 2009-08-27
Also published as: HU228167B1; HUP0800109A2; HU0800109D0; WO2009104031A3

Abstract

The invention is a split sealing ring structure for pistons, which is placed in the groove of a piston, and includes a flexible steel internal ring as well as at least one external ring of soft iron material, and the internal ring meets the external ring in a conical surface that is angular to the plane of the ring structure, which includes a waved ring (8) of flexible material between the lower part of the piston (1) of the groove (3) in radial direction and the internal ring (4).

Description

SPLIT SEALING RING FOR PISTONS

Subject of the invention is a split sealing ring for pistons, especially for pistons with support insert, which sealing ring structure is placed in the groove of the piston, and includes a flexible steel internal ring and at least one external ring of soft iron, and the internal ring is contacted with the external ring in a conical surface that is angular to the plane of the ring structure.

It is known from the state of art, that in internal-combustion engines and in compressors, there are compression ring or oil-scraper ring is used in the cylinder; these are circular rings made of split plane, generally of steel or alloyed material, basically of grey iron casting. It is known from practice that operational efficiency of piston rings depends on thermal expansion. Thus the known and commonly used piston rings, less follow size changes that are desirable according to their thermal expansion, and are not perfect in respect of dilatation. Therefore efficiency, fuel consumption of the engine are unfavourable, and the rings often seize or get stuck in the cylinder, especially at higher temperatures, or are knocked out from the groove, do not perform their tasks of gap filling. They do not seal the oil but instead let it through, bring the lubricating oil into the combustion space.

Hungarian patent document published under no. 185/90 describes a split piston ring for any piston systems. In this solution the split piston ring consists of a structure formed with its internal diameter and sheet distance for the groove of the piston, with its external diameter for the bore-hole of the cylinder in such a way that the piston consists at least of two parts, and both parts in conical angle, or one part in conical angle and the other part fitted with radius surfaces, or both connecting parts with radius, polished surfaces are placed in the groove of the piston. Material of the piston ring consists of materials of traditional composition. The ring, due to its construction, prevents jamming of the piston, but in spite of this, it can not provide sealing during operation perfectly.

Patent specification WO99/56042 describes a split piston ring, characterised in its material, which consists of two parts: of an internal ring of spring steel material and of an external soft iron ring. The two rings meet each other with an inclined plane that includes an acute angle to their common plane, which allows that the spring steel ring presses the soft iron ring to the internal wall of the cylinder in every condition. Due to meeting in an acute angle, forces that effect onto the side wall of the groove that receives the ring, emerging parallel with the direction of the longitudinal axle of the cylinder can easily press the split ring onto the groove. A further disadvantage is that the ring can move in the direction of the other size of the groove that is towards the axle of the cylinder, because there a gap to provide some tolerance must be formed in order to avoid seizing. This, however, allows a smaller displacement of the piston from the ideal central position within the cylinder. This displacement also allows that the piston moves so that its lower and upper parts get to different distances from the wall of the cylinder, and thus take an angular position. This is disadvantageous anyhow both for operation and for wearing characteristics.

A further problem may emerge with the described split sealing ring, where the first sealing ring that falls towards the combustion space - the so-called fire ring - because of the slot on it allows a smaller gas transmission - blow-out -, because the steal ring does not reach the wall of the cylinder in radial direction. However, slotting is essentially required for both ring members, thus the mentioned can not be solved in a simple way.

The object of the invention is to create - by elimination of the above deficiencies - a sealing ring structure that beside all this does not require any structural modification on the existing pistons and cylinders, and can be manufactured in a cheap way.

The invention is based on the recognition that the space that provides the mentioned tolerance must be filled by an elastic element in the depth direction of the groove, which will partly centralise the current position of the sealing ring relative to the piston, and partly allows via the provided spring force a possible further division of the sealing ring into three parts, and thereby the complete elimination of blow-out problems.

In general aspect of the invention, the split sealing ring structure according to the introductory paragraph, further comprises a waved ring of flexible material between the radial lower part of the groove of the piston and the internal ring.

The invention will be further presented by drawings, where: Fig. 1 is a cross section of a part of the piston, which is close to the cylinder and includes a groove, with a split ring according to the invention and a flexible element,

Fig. 2 is the flexible element according to Fig. 1 in top view as well as in front view and also in side view projected,

Fig. 3A is the internal member of a split sealing ring in top view,

Fig. 3B is the internal member of a split sealing ring in cross section,

Fig. 4A is one of the external members of the split sealing ring according to the invention in top view,

Fig. 4B is one of the external members of the split sealing ring according to the invention in cross section,

Fig. 5A is the other external member of the split sealing ring according to the invention in top view, and

Fig. 5B is the other external member of the split sealing ring according to the invention in cross section.

Fig.1 is a cross section of a part of the piston 1 , which is close to the cylinder 2 that includes the groove 3 with a split piston ring 4, 5, 6 according to the invention, where the internal ring meets the external ring in the conical surface that is angular to the plane of the ring structure, which is shown on the picture as a skew straight line. On the lower bottom part of the groove 3 of the piston 1 in radial direction there is a flexible element, where this latter is accomplished in the form of a waved ring 8. There are apertures, lightenings 9 are present in that for weight reduction. In the groove 3, after the waved ring 8, moving in depth direction outwards, the internal ring 4 made of steel is found, which in the way known from the state of technique, but in a higher angle - approximately in 45 degrees - meets the other member. Generally it can be said that the split ring structure according to the invention allows that the conical surface 14 closes an angle of more than 40 degrees with the plane of the ring structure. Expediently we can choose basically an angle of 45 degrees. The external sealing ring is divided into two parts, into a first external ring 5 and into a second external ring 6. The dividing fitting surface 7 is perpendicular to the wall of the cylinder 2. Its advantage is that the position of the slots can be rotated relative to each other, thereby the first 5 and the second 6 - A -

external rings provide a circular hermetic closing in the slot 10 between the piston 1 and the cylinder 2.

The waved ring 8 is shown in Fig. 2 in top view, projected also its front and side views so that the series of rectangular lightenings 9 that does not reduce springing characteristics but significantly reduces the mass of the waved ring 8. The lightenings 9 in the waved ring 8 of spring steel material can be created expediently by pressing. Geometric configuration of the waved ring 8 allows to expand its effective internal diameter to some extent, which is necessary for its placement into the groove 3.

In Fig. 3A and 3B the internal ring 4, in Fig. 4A and 4B the first externaljing 5, and in Fig. 5A and 5B the second external ring 6 are shown, all in top view and in cross section, respectively. The internal ring 4, as we mentioned, is of steel and works as a spring that provides a force directed outwards, which presses the external member - which expediently consists of two parts - of the split sealing ring structure to the wall of the cylinder. It includes a slot 13, which can also be relatively bigger. The first 5 and second 6 external rings expediently are of identical material, soft iron or similar material that provides similar sealing and bears even higher wear. This does not crape the internal wall of the cylinder, thereby increases the lifetime of the machines with pistons without cylinder reboring. Although on the drawings the slots 11 and 12 of the first 5 and second 6 external rings are standing in the same direction, these mounted are rotated relative to each other, thereby due to overlapping they result in hermetic closing around along the cylinder wall. This is advantageous especially in case of the fire ring.

Fitting surface 7 of the internal 4, as well as first 5 and second 6 external rings according to Fig. 1 expediently is polished, of matching smooth design as much as possible. Moreover the conical surface 14, in which the first 5 and the second 6 external rings meet the internal ring 4, can close with the plane of the rings a larger angle than in case of the sealing rings that are known from the state of technique. Its reason is that the additionally applied waved ring 8 plays not only the role of exacting but increases the pressure of the complex structure towards the cylinder wall. Increase of the angle of the mentioned conical surface 14, however, decreases the possibility of jamming of the ring structure into the groove, thereby it increases operational safety of the machines with pistons.

Claims

1. Split sealing ring structure for use with pistons, which is placed in a groove of a piston, and comprising a flexible steel internal ring as well as at least one external ring of soft iron material, and the internal ring meets the external ring in a conical surface that is angular to the plane of the ring structure, characterised in that it further comprises a waved ring (8) of flexible material between the radial lower part of the groove (3) of the piston (1) and the internal ring (4).

2. Split sealing ring structure according to claim 1 , characterised in that the waved ring (8) is made of spring steel shaped in circular form.

3. Split sealing ring structure according to claim 1 or 2, characterised in that the waved ring (8) comprises apertures as lightenings (9).

4. Split sealing ring structure according to claims 1-3, characterised in that the external ring is formed of a first external ring (5) that has a slot (11) and a second external ring (6) that has a slot (12), where they meet a fitting surface (7) that is parallel with the plane of the ring so that the slots (11 , 12) are not overlapped.

5. Split sealing ring structure according to claims 1-4, characterised in that the conical surface (14) closes an angle of more than 40 degrees with the plane of the ring structure.

6. Split sealing ring structure according to claims 5-4, characterised in that the conical surface (14) closes basically an angle of 45 degrees with the plane of the ring structure.