JPS61248965A - Sliding seal ring - Google Patents

Abstract

PURPOSE:To reduce thermal expansively and thermal softening property to improve lubricating property in use by mixing 5 to 30wt% of carbon fiber with Teflon to from a seal ring. CONSTITUTION:15% of carbon fiber chops of 14mu diameter and 0.15mm length are mixed with Teflon powder, preliminarily shaped into the cylindrical form by a cold press, heated and baked in an oven at 375 deg.C. The cylinder obtained from the baking is cut into a predetermined shape by a cutting tool to form a seal ring 1. Even when room temperature is raised gradually to 125 deg.C under one million times of rotation with the max fluid pressure of 10kg/cm<2>, oil leakage over the whole process does not take place.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sliding seal ring, for example, a seal ring that seals a reciprocating rod and a sliding portion of the rod cover.

(Conventional technology and problems) When there are two sliding seal rings, when inserting the seal rings,
There is a particular problem in that frictional resistance during operation poses a problem, and a large interference cannot be achieved.

In order to reduce the interference and exhibit sealing performance, the material must have low thermal expansion, low coefficient of friction, little wear, and be moderately hard at high temperatures.

Conventionally, as such a sliding seal ring used in combination with an O-ring, which has wear resistance and a low coefficient of friction, a material made of Teflon mixed with molybdenum disulfide, glass fiber, bronze, etc. has been used.

The shape of the Teflon seal ring mixed with these as shown in Figure 1 (Seal 1 outer diameter 45.2φ, width 5, OIJ song wire diameter 2.5φ, rod 4 outer diameter 38φ, all units are m)
The physical property values for m) are shown in Table 1.

That is, the molybdenum disulfide Teflon seal ring is
Cannot be used at high temperatures due to large thermal expansion and thermal softening. In addition, glass fiber-containing and bronze materials have low thermal expansion and thermal softening,
It has poor elasticity and poor sealing performance at low pressures (less than 4 kg/an!). Although it can be used at high temperatures and high pressures, there are problems such as damage to the mating rod during use.

(Means for Solving the Problems) The present invention solves the conventional problems by mixing 5 to 30% by weight of carbon fibers into Teflon to form a seal ring.

That is, the carbon fiber-containing Teflon seal ring
As shown in the table, the thermal expansion and thermal softening properties are low, and the hardness is between molybdenum and bronze. Furthermore, when in use, carbon has an extremely lubricating surface that does not damage the mating rod, making it ideal for use as a sliding seal ring.

The physical properties depend on the mixing rate of carbon fiber, but the tensile strength is 200 kg/ad with a mixing rate of 5% and 160 kg/ad with a mixing rate of 30%.
/ad, which is not much different from other contaminants. However, if 30% or more is mixed in, the elongation rate is extremely reduced to 10% or less, making it difficult to insert it into the seal groove and causing poor sealing at low pressures. The coefficient of thermal expansion and softening properties depend on the mixing rate of carbon fibers in Teflon, so in practice, if the fluid pressure is 100°C or less and a load of 4 kg/-, the mixing rate is 5%, and at 100°C and a load of 6 pupils/-. If the fluid pressure is CD, the mixing rate can be 15%, and if the fluid pressure is 150° C. and a load of 12 kg/ad, the mixing rate can be 30%.

In a low temperature range, even a product with a 15% contamination rate has good sealing performance, and therefore a product with a 15% contamination rate can be used for general purpose.

(In addition, if the operation starts from a low temperature and gradually increases to a high temperature, the seal may not contain other materials.)
Oil leaks occur at low or high temperatures, so the entire temperature range cannot be covered. However, the one containing 15% can satisfy the sealing performance in the range from room temperature to 120'C1 load of 0 to 6 kg/-.

(Effects) The carbon fiber-containing Teflon seal ring of this invention has extremely good sealing properties due to low thermal expansion and thermal softening properties, and has excellent lubricity during use, so it will not damage the mating rod. do not have.

(Example) Carbon fiber chips with a wire diameter of 14 μm and a fiber length of 0.15 μm are mixed at 15% with Teflon powder, pre-shaped into a cylindrical shape using a cold press, and then heated and baked at 375° C. in an oven.

The cylinder obtained by firing is cut into a predetermined shape using a cutting tool to form the seal ring 1. Each dimension is as described above.

Insert it together with the O-ring 2 into the seal groove 3 as shown in FIG. 4 is a rod that reciprocates in the direction of the arrow in the figure. The operating conditions were a cycle number of 300 times/min, a stroke of 20 times, an average speed of 0.2 m/sec, and heavy oil was used as the fluid.

The temperature was gradually raised from room temperature to 125°C, and the maximum fluid pressure was 10 kg/cd, and the engine was rotated 1 million times, but no oil leakage occurred during the entire process.

For comparison, we tested other Teflon seal rings under similar conditions, and found that with molybdenum disulfide at a mixing rate of 5%, the mixing rate was 80°C, fluid pressure was 5 kg/cd, and 180,000 rpm. 70'C with 25% glass fiber
1 fluid pressure 4kg/ai, 30,000 rotations, and mixing ratio 60
% of bronze users, oil leakage occurred at 40°C, fluid pressure of 4 kg/J, and 10,000 revolutions.

Table 1 Admixtures Mixing rate Coefficient of thermal expansion Load (%) (
xlO-') (kg/cd) Molybdenum disulfide 5
1.44 1.2 Glass fiber 25
0.6 1.8 Bronze 60
0.62 2.2 Carbon fiber 5 1
．． 1 1.315 0.82 1.6 30 0.55 2.0 (However, the mixing ratio is weight %, the thermal expansion coefficient is 150" at 0, the load is 10% elongation at 100°C) 4

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a carbon fiber-containing Teflon seal ring fitted into a seal groove. l...Seal ring 2...O-ring 3...Seal groove 4...Rod agent Patent attorney Masaharu Yamagami r;ii Hitomi-naunrokukaji 1 Procedural amendment Patent application 2 filed on May 26, 1985 on May 26, 1985 Name of the invention Sliding seal ring 3 Relationship to the case of the person making the amendment Patent applicant address 1-chome Nishijiriike-cho, Nagata-ku, Kobe, Hyogo Prefecture No. 3 26
No. 4 Agent 5 Date of amendment order (voluntary) 6 Number of inventions to be increased by amendment None 7 Subject of amendment Correct the "Detailed Description of the Invention" column of the specification and Figure 1 of the attached drawings. (2) Figure 1 of the attached drawings is corrected as shown in the attached sheet. that's all

Claims (1)

[Claims] (1) A sliding seal ring made of Teflon mixed with 5 to 30% by weight of carbon fiber.