JPH11218133A - Manufacture of carbon sliding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain specific air permeation quantity as a sliding material of an air bearing or the like and to reduce the generation of dust caused by air pressure by impregnating carbon material with a thermosetting resin and hardening it. SOLUTION: Phenol resin, furan resin or epoxy resin is used as thermosetting resin. As carbon material to a base material, general carbon material formed by kneading, crushing, forming, baking and graphitizing aggregate such as coke powder, graphite powder or carbon black using binding material such as coal tar or tar pitch can be used. Further as carbon material, it is desirable that the air permeation quantity is 15 cc/cm<2> .min. The thus obtained carbon material is impregnated with the thermosetting resin and hardend so as to obtain a function of reducing the quantity of dust generated by air pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a carbon sliding member for a bearing such as a hydrostatic air bearing.

[0002]

2. Description of the Related Art Carbon materials are porous materials and have been used as sliding materials (sliding pieces) for hydrostatic air bearings because of their excellent sliding characteristics and machinability. However, since the variation in the amount of air permeation is large, the amount of air permeation in a predetermined range (generally 15 to 300 cc / cm ² ···
(arbitrary range between min.) is selected and used, so that the material yield is poor. In addition, there is a problem that particles that fall off inside the carbon material or cutting powder during machining that has entered the openings are discharged by air pressure.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an air permeation (for example, 15
It is an object of the present invention to provide a manufacturing method for manufacturing a carbon sliding material which is less than 300 cc / cm ² · min) and generates less dust due to air pressure.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a carbon sliding material, wherein a carbon material is impregnated with a thermosetting resin and cured.

The present invention also relates to a method for producing a carbon sliding material having an air permeation amount after impregnation and curing of the thermosetting resin of 15 to 300 cc / cm ² · min.

The present invention also relates to a method for producing a carbon sliding material in which the thermosetting resin is a phenol resin or an epoxy resin.

[0007] Further, the method of manufacturing the carbon sliding material includes:
The present invention relates to a method for manufacturing a carbon sliding material for a hydrostatic air bearing.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermosetting resin used in the present invention includes a phenol resin, a furan resin, an epoxy resin, and the like. From the viewpoint that a good carbon sliding material can be obtained, a phenol resin or an epoxy resin is used. preferable. As a carbon material which is a substrate to be impregnated with a thermosetting resin and cured, general carbon materials, that is, aggregates such as coke powder, graphite powder, carbon black, coal tar,
Using binder such as tar pitch, kneading, crushing, molding,
Fired and graphitized materials can be used.

[0009] As the carbon material, preferably, the amount of air permeation is 15cc / cm ² · min or more, more preferably used as the 50~400cc / cm ² · min. If a carbon material having an air permeation amount of less than 15 cc / cm ² · min is used, the air permeation amount after resin impregnation and curing is insufficient, so that it may not be applicable as a carbon sliding piece for an air bearing.

The production method of the present invention can use a carbon material whose air permeation amount is out of the upper limit of the allowable range as the target carbon sliding material, so that the material yield is excellent. .

Here, the air permeation amount in the present invention is as follows: sample thickness: 5.0 (mm), measured cross-sectional area: 20.0
(Mm ² ), air pressure: 5 (Kg / cm ² ), means a value obtained by measuring the flow rate with a mass flow meter and calculating.

In producing the carbon material used in the present invention, kneading is generally carried out by using a double-armed kneader or the like, preferably by using a material such as an aggregate and a binder, preferably from 200 to 30.
This is performed by heating and kneading at 0 ° C.

The pulverization is performed so that the material obtained by the kneading is pulverized into powder having a size of 10 to 30 μm by using various pulverizers.

The molding is preferably performed by pressing the powder obtained by the pulverization with a hydraulic press or the like, preferably at 800 to 1200 kg / g.
It is performed so as to form a block shape with a pressure of cm ² . The shape of the block is not particularly limited, and it can be formed into a rectangular parallelepiped, a column, or the like.

The size of the block is 500 mm ×
It is preferable that the size is not more than a 500 mm × 500 mm cube because the resin can be sufficiently impregnated into the inside.

The calcination is carried out in a reducing atmosphere, preferably at 80
This is performed by raising the temperature to 0 to 1200 ° C. The heating time is preferably 300 to 500 hours. As a method of raising the temperature in a reducing atmosphere, there is a method of packing carbon powder around a molded body.

Graphitization is performed by raising the temperature of the fired product to a temperature of about 2800 to 3200 ° C. using an electric furnace such as an Acheson furnace.

The carbon material thus obtained is impregnated with a thermosetting resin and cured. By this process, the thermosetting resin functions to impregnate the pores of the carbon material and reduce the voids between the particles so that the amount of air permeation falls within a predetermined range. It acts to reduce the amount of dust generated by air pressure by increasing the force and reducing the shedding of particles.

The carbon material is impregnated with the thermosetting resin by impregnating the impregnating liquid obtained by diluting the thermosetting resin with a solvent under a reduced pressure of preferably 20 mmHg or less, more preferably 5 mmHg or less. 2 kg / cm ² or more, more preferably it is carried out by pressurizing over 1 hour at a pressure of 3~10Kg / cm ^2. The type of the solvent is not particularly limited, and preferred are those that are easily volatilized such as methanol, acetone, and methyl ethyl ketone.

The viscosity of the impregnating liquid is 10 to 50 cps.
Is preferable, and 20 to 30 cps is more preferable. The nonvolatile content (resin content) of the impregnating liquid is preferably 10 to 50% by weight, more preferably 10 to 30% by weight in the case of a phenol resin, and 20 to 80% by weight in the case of an epoxy resin.
Is preferable, and 40 to 60% by weight is more preferable.

The curing after impregnation is preferably between 150 and 28
This is performed by raising the temperature to 0 ° C. for 8 to 35 hours. The resin residue after curing is determined according to the target air permeability, but is preferably 1 to 15% by weight, more preferably 1 to 8% by weight in the carbon material after curing. preferable.

The carbon sliding material thus obtained is extremely useful as a material for a sliding piece used for a guide (slider) of a precision positioning device or a hydrostatic air bearing such as a high-speed rotating bearing.

The processing of the carbon sliding material into a predetermined shape can be performed by machining or the like. Also, the impregnation step
It may be performed after the carbon material before impregnation is processed into a predetermined shape as a sliding material or a shape close thereto.

The shape of the carbon sliding material is determined according to the purpose, and is not particularly limited. An example of a ring-shaped static pressure air bearing is illustrated. FIG. 2 is a perspective view of the hydrostatic air bearing, and FIG. 3 is a sectional view showing an outline of a state where a shaft is mounted on the hydrostatic air bearing. In FIG. 3, the air is fed in as indicated by the arrows, so that the hydrostatic air bearing 5 and the shaft 6
A space is generated between the two, forming a non-contact state.

[0025]

Embodiments of the present invention will be described below.

Example 1 As an aggregate, calcined pitch coke (trade name: LPC-A, manufactured by Nippon Steel Chemical Co., Ltd.) was pulverized to an average particle size of 14 μm, 55% by weight, and a homemade graphite powder (average particle size: 22 μm). 5
40% by weight of a binder pitch (PKL manufactured by Kawasaki Steel Co., Ltd.) as a binder is added to the mixture at a temperature of 25% by weight.
Kneaded at 0 ° C. for several hours.

This kneaded material is pulverized to an average particle size of 25 μm,
This pulverized powder is pressed with a hydraulic press at a pressure of 1000 kg / cm.
^It was molded into a block of size 500 × 500 × 200 mm in ² .

This molded product is heated at 1000 ° C. in a reducing atmosphere.
And baked for 450 hours.

The calcined product is heated to a temperature of about 3000 ° C. in an Acheson furnace to be graphitized, and the amount of air permeation is measured by the method described above to obtain 350 cc / cm ² · m.
in carbon material.

Next, this carbon material was placed in a pressure vessel for 3 m.
After degassing to mHg, a phenol varnish (manufactured by Hitachi Chemical Co., Ltd., trade name: VP112N, nonvolatile content: about 60% by weight) and methanol were mixed at a weight ratio of 1: 2, and an impregnating liquid (resin content: 18% by weight, viscosity: 25 cps) was used. Impregnated, 4
It was pressurized at a pressure of Kg / cm ² for 2 hours.

Then, the carbon material containing the impregnating liquid was heated to 250 ° C. for 15 hours and cured to obtain a carbon sliding material. The residual resin content was 1.9% by weight.

The physical properties and the amount of air permeation of the carbon sliding material thus obtained were measured.

As an indicator of dust generation, as shown in FIG. 1, cleaning water 3 after cleaning a test piece 4 in a test tube 2 with an ultrasonic cleaner (125 W / 100 V) 1 for 5 minutes.
Was evaporated and the weight of the residue (dust generated) was measured.

As a result, the air permeation amount was 180 cc / cm
² min, the amount of residue by ultrasonic cleaning is 2 m
g. Table 1 shows the measurement results.

Example 2 From a carbon material of another lot obtained in the same manner as in Example 1, a block having an air permeability of 400 cc / cm ² · min was degassed to 3 mmHg in a pressure vessel, and an epoxy resin ( Ciba-Geigy product name CT-200 solid), methyl ethyl ketone, and a curing agent (product name: HN2200 manufactured by Hitachi Chemical Co., Ltd.) mixed at a weight ratio of 2: 1: 1 (epoxy resin content 46% by weight, viscosity 28 cps).
And pressurized at a pressure of 4 kg / cm ² for 2 hours.

Then, the carbon material containing the impregnating liquid was cured by raising the temperature to 200 ° C. for 30 hours. The residual resin content of the obtained carbon material was 1.8% by weight.

The carbon sliding material obtained by impregnating and curing in this way was measured for physical properties, air permeation and dust generation.

As a result, the air permeation amount is 250 cc / cm
² min, the amount of residue by ultrasonic cleaning is 3 m
g. Table 1 shows the measurement results.

Comparative Example 1 The carbon material before impregnation and curing in Example 1 was measured for physical properties, air permeation amount and dust generation.

As a result, the air permeation amount was 350 cc / cm
² min, the amount of dust generated by the ultrasonic cleaning was 5 mg. Table 1 shows the measurement results.

Comparative Example 2 The carbon material before impregnation and curing in Example 2 was measured for physical properties, air permeation amount and dust generation.

As a result, the air permeation amount was 400 cc / cm
² min, the amount of dust generated by the ultrasonic cleaning was 7 mg. Table 1 shows the measurement results.

[0043]

[Table 1]

As is clear from Table 1, the air permeation amount of Examples 1 and 2 is smaller than that of Comparative Examples 1 and 2, and the air permeation amount is in a suitable range (15 to 300 cc / cm ^2.
min). In addition, dust generation is small.

[0045]

According to the present invention, an air permeability (15 to 300 cc / cm ² · m) suitable for a sliding material such as an air bearing is used.
in) and a carbon sliding material with less generation of dust can be obtained.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a test piece cleaning device for dust generation evaluation.

FIG. 2 is a perspective view showing a shape of a hydrostatic air bearing which is an example of a carbon sliding material manufactured according to the present invention.

FIG. 3 is a cross-sectional view showing a state where a shaft is mounted on a hydrostatic air bearing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic cleaner, 2 ... Test tube, 3 ... Distilled water, 4 ... Test piece, 5 ... Static pressure air bearing, 6 ... Shaft.

Claims (4)

[Claims] 1. A method for producing a carbon sliding material, wherein a carbon material is impregnated with a thermosetting resin and cured. 2. The method for producing a carbon sliding material according to claim 1, wherein an air permeation amount after impregnation and curing of the thermosetting resin is 15 to 300 cc / cm ² · min. 3. The method according to claim 1, wherein the thermosetting resin is a phenol resin or an epoxy resin. 4. The method for producing a carbon sliding material according to claim 1, which is for a hydrostatic air bearing.