JPH04327063A - Piston ring device - Google Patents

Abstract

PURPOSE:To keep the sliding characteristic of a piston ring and prevent the stepped deformation of the low pressure side which is a side surface opposite to a compression chamber side of a piston. CONSTITUTION:A piston ring operation 31 is formed of two piston rings different in material, and of the two piston rings, a tetrafluoroethylene resin piston ring 33 is disposed on the high pressure side, and a thermosetting resin piston ring 32 is disposed on the low pressure side.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates to a piston ring device, and more specifically, the present invention relates to a piston ring device, and more specifically, the piston ring device is installed in a ring groove carved on the outer circumferential surface of a piston, and is mounted between the piston outer circumferential surface and the inner wall surface of the cylinder. The present invention relates to a piston ring device for keeping a clearance part airtight. The device of the present invention is applied to internal combustion engines, compressors, hydraulic cylinders, so-called reciprocating machines such as Stirling engines and refrigerators, as well as hydraulic rotary shaft seal rings and the like.

0002

2. Description of the Related Art Conventionally, as an example of a reciprocating compressor commonly used, the one shown in FIG. 3 has already been proposed. In this reciprocating compressor 10, a lower end of a connecting rod 13 is attached to a crank 11 fixed to a rotating shaft of a power source such as a motor via a bearing 12, and a piston pin 14 is attached to an upper end of the connecting rod 13. The piston 15 is rotatably attached to the piston 15 via the piston 15. Ring grooves 16 and 17 are carved on the outer peripheral surface of the piston 15.
A rider ring 19 is attached to the piston 15 to prevent metal contact between the piston 15 and the cylinder 18. On the other hand, a piston ring 20 is installed in the ring groove 17 in order to keep the so-called piston clearance area between the outer peripheral surface of the piston 15 and the inner wall surface of the cylinder 18 airtight as the piston 15 reciprocates. Ru.

As shown in FIG. 2, the piston ring 20 has a substantially rectangular cross section, and a tension ring 21 made of steel is inserted from the inner peripheral surface side opposite to the outer peripheral surface that slides on the inner wall surface of the cylinder 18. Therefore, a simple structure in which the piston ring 20 is pressed against the inner wall surface of the cylinder 18 is generally adopted.

During the suction stroke of the piston 15, that is, when the piston 15 descends, the suction valve 23 opens due to the negative pressure generated in the compression chamber 22, and atmospheric air is sucked in through the suction pipe 24.

During the compression stroke of the piston 15, that is, when the piston 15 moves upward, the air pressure compressed within the compression chamber 22 causes the exhaust valve 25 to open and the air pressure to pass through the exhaust pipe 26 to the normal tank (not shown). stored in

However, the conventional compressor having the above structure,
In particular, in compressors that do not use lubricating oil, the piston ring 20 is made of polytetrafluoroethylene resin with excellent self-lubricating properties, and is filled with carbon, glass fiber, etc. to improve strength and wear resistance. A so-called resin ring made of a mixture of materials is generally used. When such a non-lubricated compressor is operated for a long time, the piston ring 20
Due to the heat generated by sliding with the inner wall surface of 8, the heat of compression, etc., the material strength is significantly reduced.

As a result, the piston ring 20 protrudes into the piston clearance portion 27 and is deformed, and the pressure inside the compression chamber 22 causes the piston ring 20 to fall and deform toward the crankcase. As a result, a stepped deformation 28 occurs on the sealing surface with the piston ring groove 17, as shown by the broken line in FIG. The wear of the corner portion of the outer circumferential surface on the 22 side increases, and the wear also occurs in a substantially tapered shape 29 as shown by the broken line in FIG. Therefore, the compressed air in the compression chamber 22 easily enters the wedge-shaped portion 30 formed between the outer circumferential surface of the piston ring 20 worn into the tapered shape 29 and the inner wall surface of the cylinder 18 . Therefore, the airtightness of the piston ring 20 decreases, and the compression chamber 2
However, there was a problem in that the leakage amount of the compressed air inside 2 increased and the volumetric efficiency decreased.

Furthermore, in order to maintain the airtightness of the conventional non-lubricated compressor shown in FIG. A conceivable method is to manufacture the piston ring 20 from a thermosetting resin and assemble it into the piston ring groove 17. However, when the compressor is operated in this manner, the piston ring 20 has a somewhat inflexible material, which deteriorates the airtight performance, increases the amount of compressed air leakage, and results in a decrease in volumetric efficiency. This led to problems.

[0009]

SUMMARY OF THE INVENTION Therefore, in order to solve the problems of the prior art described above, the present invention aims to maintain the sliding characteristics of the piston ring and ensure airtight performance, and to reduce the compression chamber of the piston ring. The technical problem is to prevent stepped deformation on the low pressure side, which is the opposite side.

0010

[Means for Solving the Problems] In order to solve the above technical problems, the technical means taken in the present invention is to divide the piston ring into two rings made of different materials, and to A conventionally used piston ring made of tetrafluoroethylene resin is placed on the high pressure side), and a piston ring made of thermosetting resin is placed on the crankcase side (generally the low pressure side).

[0011]

[Operation] By adopting the above-mentioned technical means, the flexibility of the material of the piston ring made of tetrafluoroethylene resin placed on the high pressure side allows the piston ring to follow the cylinder inner wall surface without impairing its ability to follow the inner wall surface of the cylinder. In other words, the airtight performance of the piston ring is maintained. The material of the thermosetting resin piston ring placed on the low-pressure side ensures strength during high-temperature operation, and the piston clearance can be covered by the piston ring, ensuring that stepped deformation of the piston ring on the low-pressure side is prevented. As a result, airtight performance can be maintained for a long period of time.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

In order to prevent stepped deformation of the low pressure side side surface of the piston ring 20 for maintaining airtightness in the conventional non-lubricated compressor shown in FIG. 3, one piston ring groove 17 is provided.
As shown in FIG.
a piston ring 32 made of thermosetting resin disposed in;
It is composed of a piston ring 33 made of tetrafluoroethylene resin mixed with various filling materials such as carbon and glass fiber, which is placed on the high pressure side (generally on the compression chamber side). The thermosetting piston ring 32 and the tetrafluoroethylene resin piston ring 33 have a structure in which two pieces are stacked and joined in the axial direction, and the axial thickness dimensions of both piston rings 32 and 33 are approximately the same. ing. The piston ring 31 is extended by a steel expander ring 21 mounted so as to be in contact with the inner peripheral surface of the piston ring, and
It has a seal structure that is pressed against the inner wall surface of the

[0014]

As explained above, in the piston ring device according to the present invention, in the so-called hybrid type in which two piston rings made of different materials are installed in one piston ring groove, compression Due to the flexibility of the material of the piston ring made of tetrafluoroethylene resin disposed on the high pressure side of the chamber, the ability of the piston ring to follow the inner wall surface of the cylinder is not impaired. At the same time, due to the material strength of the thermosetting resin piston ring placed on the low pressure side of the crankcase during high temperature operation, the piston clearance can be covered by the piston ring. Deformation is reliably prevented. As a result, it is possible to maintain airtight performance for a long period of time, and it is possible to provide a piston ring device with a long life.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a piston ring device according to the present invention.

FIG. 2 is a partial sectional view showing a conventional piston ring device.

FIG. 3 is a sectional view showing the structure of a conventional non-lubricated compressor.

[Explanation of symbols]

15 Piston 17 Piston ring groove 18 Cylinder 22 Compression chamber 31 Piston ring device

Claims (3)

[Claims] 1. In a hybrid piston ring device in which two piston rings made of different materials are installed in one piston ring groove carved on the outer circumferential surface of the piston, A piston ring device in which a piston ring made of tetrafluoroethylene resin is arranged on the high pressure side and a piston ring made of thermosetting resin is arranged on the low pressure side. 2. Of the two piston rings, the tetrafluoroethylene resin piston ring disposed on the high-pressure side and the thermosetting resin piston ring disposed on the low-pressure side are aligned in the axial direction. The piston ring device according to claim 1, wherein the piston ring device has a composite piston ring structure in which the piston rings are overlapped and joined. 3. In the composite piston ring structure, the axial thickness of the tetrafluoroethylene resin piston ring and the thermosetting resin piston ring are substantially the same. The piston ring device described in.