JPH0223748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oilless piston equipped with a piston ring with an abutment made of self-lubricating synthetic resin.

Conventionally, when installing a self-lubricating synthetic resin piston ring on a piston, especially a piston ring whose main component is tetrafluoroethylene resin, the wall thickness must be quite thick (for example, 15 mm) to prevent gas leakage. However, because of this, the frictional resistance of this type of piston ring was extremely high, and the life of the piston ring was extremely short. However, as a result of intensive research, the present inventor found that even if the wall thickness of the piston ring is made considerably thinner (for example, 3 mm), by increasing the number of piston rings installed, the amount of gas leakage can be reduced, and the friction with the cylinder can be reduced. They found that the resistance was significantly reduced and completed the present invention.

That is, the present invention provides a piston with a large number of piston ring grooves having extremely small groove widths, a self-lubricating synthetic resin knock pin at the bottom of each piston ring groove, and shifts the positions of the respective knock pins. , in each of the piston ring grooves, a thin self-lubricating synthetic resin piston ring with an abutment, which has two self-lubricating synthetic resin pawls protruding from its inner peripheral surface, is placed between the two pawls. A tension ring is stretched over the inner circumferential surface of the piston ring so that the two claws can be interposed between the cut ends of the tension ring, and self-lubricating synthetic resin is used. This provides an oil-less piston that minimizes the frictional resistance and gas leakage of manufactured piston rings.

The present invention will be explained below based on embodiments with reference to FIGS. 1 to 3.

10 is a piston, which has many (5 mm) piston ring grooves 11 with extremely small groove widths (3 mm).
) provided in each piston ring groove 110,
Knock pins 111 are attached at positions shifted by 180 degrees from each other. Each knock pin 111 is made of a self-lubricating synthetic resin material such as perfluoroalkyl, which has high heat resistance, strength, and hardness.

20 is a piston ring with an abutment made of self-lubricating synthetic resin whose main component is tetrafluoroethylene resin,
The wall thickness is thin enough to fit tightly into the groove width of the piston ring groove 11, the abutment 21 is cut straight or at an angle, and the inner circumferential surface 201 has two pawls 22 and two at positions corresponding to the abutment 21. 22
stands out. Each claw 22 has a knock pin 11
A self-lubricating synthetic resin material similar to 1 is used. The distance between the two claws 22 and 22 must be at least enough to hold the knock pin 111.

Reference numeral 30 denotes a tension ring that is fitted onto the inner circumferential surface 201 of the piston ring 20 and is tensioned so that the two pawls 22 of the piston ring can be interposed between the cuts 31.

Therefore, after inserting the tension ring 30 into each piston ring groove 11 of the piston 10, the piston ring 20 is fitted so that the tension ring 30 can be tensioned on the inner peripheral surface 201 of the piston ring 20,
Furthermore, if the dowel pin 111 is placed between the two pawls 22 and 22 of the piston ring, and the two pawls 22 and 22 are interposed between the cuts 31 of the tension ring, the abutment 21 of each piston ring 20 will be , are positioned offset from each other by 180 degrees and are closed by each tension ring 30.

When the oil-less piston of the present invention as described above is used in a cylinder (not shown), back pressure is less likely to be applied to each piston ring 20, and even if back pressure builds up, the wall thickness is thin, so the braking effect on the cylinder is small, and The frictional resistance with the cylinder is extremely low, and a long life can be maintained. Since the positions of the joints 21 of the piston rings 20 are shifted, the amount of gas leakage can be minimized by increasing the number of piston rings 20. In this case, since the piston rings 20 are thin, the number of piston rings 20 can be increased. However, there is an advantage that the frictional resistance increases only slightly.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a front view, FIG. 2 is a longitudinal sectional view, and FIG. 3 is taken along A-A in FIG. 1.
FIG. 10... Piston, 11... Piston ring groove, 1
DESCRIPTION OF SYMBOLS 10...Same groove bottom, 111...Knock pin, 20...Piston ring, 201...Same inner peripheral surface, 21...Cut, 2
2...Claw, 30...Tension ring, 31...Tension ring cut.

Claims (1)

[Claims] 1 A piston is provided with a large number of piston ring grooves with extremely small groove widths, a self-lubricating synthetic resin knock pin is provided at the bottom of each piston ring groove, and the position of each of the knock pins is shifted, and each piston ring Insert a thin-walled piston ring made of self-lubricating synthetic resin with an abutment into the groove and having two claws made of self-lubricating synthetic resin protruding from the inner circumferential surface, and place the dowel pin between the two claws. A tension ring is stretched on the inner circumferential surface of the piston ring so that the two claws can be interposed between the cut ends of the tension ring, and the self-lubricating synthetic resin piston ring is An oil-less piston characterized by minimizing frictional resistance and gas leakage.