JPS6030457A - Piston-ring construction in internal-combustion engine - Google Patents

Abstract

PURPOSE:To make the number of rings reducible with no effect on sealability and coolingness, by making a ring spacer, whose inner circumference sticks fast to a groove bottom, adhere closely to space between adjoining upper and lower compression rings inside a single compression groove. CONSTITUTION:Inside a single compression groove 24 installed at the upside of an oil ring groove 20, two compression rings 16 and 18 are fitly installed at the upper and lower sides, an interval in which a spacer 28 is set up. Thickness in the spacer 28 is properly selected so as to make these compression rings 16 and 18 slidable at will. And, the spacer 28 is provided with fitting slits 28A contacted with each other in a state of freeness, and its inner diameter is set to be slightly smaller than a ring groove bottom diameter. In consequence, an inner circumferential surface 28B of the spacer 28 sticks fast to a ring groove bottom surface 24A in a state of being asembled.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to the structure of piston rings, particularly compression rings, for internal combustion engines.

A piston of a prior art internal combustion engine is usually formed with three ring grooves, the lower one being fitted with an oil ring and the upper two being fitted with compression rings.

However, with three ring grooves like this, the distance from the piston pin hole to the top surface of the piston (the so-called compression hide) cannot be kept below a certain value, which limits the ability to miniaturize the piston. The moment is also large, making it difficult to reduce vibration, noise, and friction.

Therefore, as a conventional technique, one in which the number of compression rings is reduced from two to one has been proposed. However, if the number of compression rings is simply reduced, although the combination height is reduced, the gas sealing performance is deteriorated, making it unusable. For this measure,
It is known that a plurality of rings are provided in one ring groove.
49.57-191849).

However, with the conventional structure, the sealing performance was still insufficient, and there were also problems with the cooling performance of the ring.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a structure in which the number of rings can be reduced without any adverse effect on sealing performance and cooling performance.

Structure of the Invention According to the present invention, a single compression ring groove is formed on the circumferential surface of the piston, a plurality of compression rings are mounted in the compression ring groove, and an annular groove is formed between adjacent upper and lower compression rings in the compression ring groove. A spacer is disposed, the circumference of the spacer is in close contact with the bottom surface of the compression ring groove, and the upper surface or lower surface of the spacer is provided so as to be in close contact with the lower surface or upper surface of the adjacent compression ring. The annular spacer between the upper and lower compression rings is
It provides a labyrinth structure that seals compressed gas, and by being in close contact with the bottom of the ring groove, it plays the role of transmitting the heat of the piston to the cylinder bore via the compression ring.

EXAMPLE To explain with reference to the drawings below, 10 is a piston;
12 is a piston pin hole. 14 is an oil ring, 1
6 and 18 are compression rings. As shown in FIG. 2A, the oil ring J4 is a well-known combination ring, consisting of upper and lower rings 141 and 142 and an expander ring 143 in between, and is attached to a ring a2o formed on the piston. 22 is an oil hole.

According to the present invention, as shown in FIG. 2, two compression rings 16 and 18 are fitted into one ring groove 24. That is, the construction of the compression ring is conventional and is mounted in the ring groove in a known manner. A spacer 28 is placed between the upper and lower compression rings. The thickness of the spacer is selected appropriately so that the compression rings 16 , 18 can slide freely within the ring groove 24 . In the free state, the spacers 28 have abutments 28 in contact with each other as shown in FIG.
A, and its inner diameter is slightly smaller than the bottom diameter of the ring groove 24. Therefore, in the assembled state shown in FIG. 2, the inner circumferential surface 28B of the spacer 28 is in close contact with the ring groove bottom surface 24A. In this assembled state of the spacer 28, the abutment 288 is slightly open, but as shown in Figure 1, the upper and lower compression rings 1
By shifting the positions of the abutments 16Δ and 188 of 6 and 1B, gas leakage through the portion q can be minimized.

When the compression rings 16 and 18 are assembled into the cylinder bore 40 in FIG. A kind of labyrinth is formed,
Performs a compressed gas seal. Furthermore, as described above, since the inner peripheral surface 28A of the spacer 28 is in close contact with the bottom surface 248 of the ring groove 24, the heat from the piston 10 is transmitted to the cylinder block via the spacer 28 and the compression ring that is in close contact with it. Heat can escape by conduction.

In the modified embodiment shown in FIG. 4, the spacer 28 is press-fitted into a ring groove 24B formed on the bottom surface 24A of the ring groove. This fitting is performed between the spacer 28 and the ring groove 24B, that is, the piston 10.
It is possible to improve the thermal contact with the substrate and promote the above-mentioned contact heat dissipation.

Effects of the Invention In the present invention, by providing a spacer ring whose circumference is in close contact with the bottom surface of the ring groove between two compression rings housed in one ring groove, a seal equivalent to that of a normal two-groove seal can be achieved. It is possible to ensure high heat dissipation from the compression ring. In addition, the compression high 1-H (distance between the top surface of the piston and the piston pin hole) can be made smaller than before, resulting in a smaller piston.

The weight can be reduced, and by reducing the moment of the piston pin Jl'fiQ by 1-, it is possible to reduce engine vibration, noise, and friction.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a piston having a screw-ring structure according to the present invention. Fig. 2A is a partially enlarged cross-sectional view of a piston ring structure of the present invention without showing it. Fig. 2B is the same as Fig. 2A, but it is attached to the cylinder bore. 3 is a perspective view of a single spacer; FIG. 4 is a partially enlarged sectional view showing the second embodiment; 10...Piston, 12...Piston pin hole, 14...Oil ring, 16 , 18... compression ring, 2
4...Ring groove, 28...Spacer. Patent Applicant Toyota Motor Corporation Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Takao Mitsui Patent Attorney Akira Yamaguchi Patent Attorney Masaya Nishiyama 1st Tel 28hi + * 2 B 1 Approximately 30

Claims (1)

[Claims] A single combination ring groove is formed on the circumferential surface of a piston of an internal combustion engine, a plurality of compression rings are installed in the compression ring groove, and an annular spacer is arranged between adjacent upper and lower compression rings in the compression ring groove. A piston ring structure for an internal combustion engine, in which the inner circumference of the spacer is in close contact with the bottom surface of a compression ring groove, and the upper or lower surface of the spacer is provided so as to be in close contact with the lower or upper surface of an adjacent compression ring.