JP2000081136A - Piston ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon-made piston ring having excellent sliding characteristic free from sticking phenomenon by impregnating a carbon base material with a resin. SOLUTION: As the carbon material to be used, those used for bearing or seal as general carbon sliding material are preferable. The quantity of a resin impregnated in the carbon material is set preferably to 3 wt.% or more to the carbon material, more preferably, to 5 wt.% or more. Its upper limit is generally 20 wt.% or less from the viewpoint of the structure of the carbon base material although it is not particularly limited. As the kind of the resin, any thermosetting resin and thermoplastic resin can be used without particular limitation. The impregnation method of the resin into the carbon base material is not particularly limited, and the impregnation can be performed by putting the carbon material and the resin in a pressure vessel followed by pressurization or applying the resin to the carbon material by use of a brush to impregnate it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon piston ring, and more particularly, to a carbon piston ring suitable for a pneumatic braking device for a sliding door closer having an aluminum cylinder pipe and a carbon piston ring. .

[0002]

2. Description of the Related Art In a sliding door closer which automatically closes a suspended sliding door with a force of a spring or the like, an air-type braking device is provided to softly close the door. Generally, in this pneumatic braking device, a pipe with a piston ring made of carbon slides in an aluminum cylinder pipe and compresses air in the aluminum cylinder pipe to generate a braking force. However, if left unused for a long period of time, there is a problem that the carbon piston ring and the aluminum cylinder are stuck and do not operate.

[0003]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies in view of the above-mentioned situation, and as a result, in a humid place, the battery action is caused by water droplets condensed on the inner surface of a carbon piston ring and an aluminum cylinder. It has been found that the corrosion may occur, and if the corrosion progresses, the piston ring made of carbon and the cylinder made of aluminum are stuck and do not operate, and the present invention has been accomplished. That is, the present invention provides a carbon piston ring having excellent sliding characteristics without the above-mentioned sticking phenomenon.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a carbon piston ring obtained by impregnating a carbon base material with a resin. The present invention also relates to a piston ring wherein the resin impregnation amount is 3% by weight or more based on a carbon base material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the carbon base material used in the present invention, those used as bearings and seals as general carbon sliding materials are preferable. That is, a carbon base material obtained by adding a binder such as coal tar and tar pitch to an aggregate such as coke powder, graphite powder, and carbon black, and kneading, pulverizing, molding and calcining can be used. There is no particular limitation on the usage ratio of the aggregate and the binder.
It is preferable to use 60 to 120 parts by weight with respect to 00 parts by weight.

In the production of the carbon substrate used in the present invention, the heat kneading is generally carried out by using a double-armed kneader or the like to remove each material such as aggregate and binder from 180 to 3 times.
It can be performed by heating and kneading at 00 ° C. In the pulverization, it is preferable to pulverize the material obtained by heat kneading using various types of pulverizers, preferably so as to have an average particle size of 10 to 30 μm.

For molding, the powder obtained by the pulverization is packed in a mold or the like, and is preferably 800
It can be carried out by forming a block at a pressure of up to 1200 kg / cm ² . The firing can be performed in a reducing atmosphere, preferably by raising the temperature to 800 to 1200 ° C. Here, the heating time is preferably 300 to 500 hours. As a method of raising the temperature in a reducing atmosphere, a method of packing carbon powder around a molded body can be used.

The carbon substrate thus obtained is impregnated with a resin. The amount of the resin impregnated is preferably at least 3% by weight, more preferably at least 5% by weight, based on the carbon substrate. Although there is no particular upper limit, it is generally 20% by weight or less due to the structure of the carbon substrate. The type of resin is not particularly limited,
A thermosetting resin or a thermoplastic resin may be used. Examples of the thermosetting resin include a phenol resin, an epoxy resin, an unsaturated polyester resin, a furan resin, a melamine resin, an alkyd resin, a xylene resin, and a polycarbodiimide resin, and examples of the thermoplastic resin include an acrylic resin. Can be mentioned. Also, a mixture of these resins can be used. Preferred resins include phenolic resins, furan resins, epoxy resins and the like. A curing agent is used depending on the type of the thermosetting resin. Examples of the curing agent include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid;
-Organic sulfonic acids such as toluenesulfonic acid and methanesulfonic acid, and carboxylic acids such as acetic acid, trichloroacetic acid and trifluoroacetic acid. When using a curing agent, it is preferable to use 0.001 to 20% by weight depending on the thermosetting resin.

There is no particular limitation on the method of impregnating the carbon base material with the resin. There is no particular limitation on the method of impregnating the carbon base material by pressing the carbon base material and the resin in a pressure vessel, or applying the resin to the carbon base material using a brush or the like. A method of impregnation can be used. Since the resin is impregnated in a solution state, when the resin is not liquid or has a high viscosity, it is dissolved in a solvent and used for impregnation. The solvent is not particularly limited, and alcohols such as methanol, aromatic hydrocarbon solvents such as toluene and xylene, and the like can be used. The amount of the solvent used is not particularly limited, and can be adjusted, for example, in the range of 5 to 95% by weight in terms of solid content. There is no particular limitation on the shape of the carbon base material to be impregnated with the resin, and the carbon block obtained by molding may be left as it is. It is preferable to impregnate in a state machined into the shape, shape of the piston ring itself, and the like. When a resin is applied and impregnated, it is preferable to apply the resin to the entire surface of the piston ring.

Although the shape of the piston ring in the present invention is not particularly limited, it generally has a circular ring shape, a cylindrical shape or the like. The size is not particularly limited. For example, when used in an air-type braking device such as a sliding door closer, a cylindrical shape having an outer diameter of 10 to 50 mm, a length of 10 to 50 mm, and a wall thickness of 1 to 5 mm may be mentioned.

FIG. 1 is a partial sectional view showing an example of a cylinder of a pneumatic braking device of a sliding door closer equipped with a piston ring according to the present invention. In FIG. 1, a piston ring 1
Is fixed to the inner aluminum pipe 4 by the O-ring 2 and the stop washer 3, and slides with the outer aluminum pipe 5. If the piston ring made of carbon of the present invention is used, it is possible to maintain a good sliding state without the piston ring 1 and the aluminum pipe 5 being fixed.

[0012]

EXAMPLE 20 parts by weight of homemade artificial graphite powder having an average particle diameter of 12 μm and 40 parts by weight of coal tar pitch were added to 40 parts by weight of pitch coke powder having an average particle diameter of 15 μm, and the mixture was heated at 180 to 200 ° C. with a double-arm kneader. After kneading, the mixture was allowed to cool. The kneaded material was pulverized to obtain a 20 μm molded powder. This molding powder was molded by a hydraulic press at a molding pressure of 1 ton / cm ² , and the molded product was heated to 1000 ° C. in a reducing atmosphere for 450 hours and calcined to a specific gravity of 1.65 and a bending strength of 400 kgf / cm 2. c
A carbon substrate having m ² and hardness of 70 (Shore hardness meter) was obtained.
The bending strength is 10mm thick, 10mm wide, 50mm long.
JCAS (Carbon Institute Standard)-
It measured according to 10-1968.

Next, the carbon substrate was machined to obtain six round bars having an outer diameter of 30 mm. Five of these were placed in a pressure vessel equipped with a valve, the pressure in the vessel was reduced, and then the valve was opened to use a phenolic resin (Sumilite Resin PR50273 (Sumitomo Durez)). The impregnating liquid diluted with methanol according to the amount of the resin impregnated (adjusted in the range of 5 to 75% by weight of methanol) was poured into the pressure vessel to impregnate the resin. After impregnation,
The substrate was heated to 250 ° C. for 15 hours and cured to obtain a substrate having a resin impregnation amount shown in Table 1. A part of the obtained base material has an inner diameter of 24m.
m and a length of 25 mm to obtain three carbon piston rings. Samples for measuring each physical property were prepared from a part. Table 1 shows the physical properties and the resin impregnation rate.

The obtained piston ring was mounted on an aluminum cylinder having the shape shown in FIG. 1, and the temperature of 80% was repeated 100 times at temperatures of 40.degree. C. and 15.degree. As a result, the samples 1 to 5 impregnated with the resin have an effect of reducing sticking as compared with the sample 6 not impregnated with the resin,
In particular, Samples 1 to 4 having a resin impregnation ratio of 3% by weight or more showed no sticking at all and showed good slidability.

[0015]

[Table 1]

[0016]

The piston ring of the present invention has excellent sliding characteristics without sticking phenomenon.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of an example of a cylinder of a pneumatic braking device of a sliding door closer equipped with a piston ring of the present invention.

[Explanation of symbols]

 Reference Signs List 1 piston ring 2 O-ring 3 stop washer 4 aluminum pipe (inside) 5 aluminum pipe (outside)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Keiichiro Mizuta 3-3-1 Ayukawacho, Hitachi City, Ibaraki Pref. Hitachi Chemical Co., Ltd. Yamazaki Plant F-term (reference) 3J044 AA20 BA06 BA10 CB40 DA20

Claims (2)

[Claims] 1. A carbon-made piston ring obtained by impregnating a carbon base material with a resin. 2. A piston ring having a resin impregnation amount of 3% by weight or more based on a carbon base material.