Carbon bearing or shaft sleeve and preparation method thereof

Abstract

The invention discloses a carbon bearing or a carbon shaft sleeve and a preparation method thereof, the carbon bearing or the carbon shaft sleeve adopts injection molding and comprises matrix powder bakelite powder and a modifier additive, and the modifier additive is composed of graphite, carbon black, carbon fiber, glass fiber and a functional additive. The carbon bearing or the carbon shaft sleeve is prepared by adopting a compression molding process, and the carbon bearing or the carbon shaft sleeve prepared by the method is simple in molding process, high in product strength, good in wear resistance and high in dimensional stability, has the characteristics of being green and environment-friendly, can pass food contact material detection, and accords with national food safety standards and FDA standards in America.

Description

Technical Field

[0001] The present invention relates to a carbon bearing or bushing, and the constituent materials of the carbon bearing or bushing for pumps belong to the field of materials science. Background Art

[0002] Carbon graphite materials have good thermal conductivity and self-lubrication properties. Using carbon to manufacture carbon bearings or bushings and other mechanical seal elements is based on the following characteristics of carbon:

[0003] 1. Strong temperature adaptability. Carbon materials have good thermal conductivity and excellent thermal shock resistance. At the same time, carbon materials have a low coefficient of thermal expansion, about one-fourth of that of steel. The lowest working temperature of carbon materials can reach -250°C, while the highest heat-resistant temperature of impregnated carbon materials can reach 680°C, and even 3000°C in a non-oxidizing atmosphere. Research shows that the higher the temperature of carbon materials, the higher the strength. The strength of carbon materials at 2200°C is even twice that at room temperature.

[0004] 2. Adaptable to harsh environments. Carbon materials can adapt to relatively harsh environments such as corrosive environments, high vacuum, and radiation environments. Carbon does not react with seawater, acids, alkalis, and solvents. At the same time, carbon bearings can also be immersed in gasoline, diesel, or other organic liquids. Carbon bearings are also applicable to high loads and occasions where they run at low speed after a long pause.

[0005] 3. Pollution-free. Carbon bearings can run for a long time without adding lubricants or only adding a small amount of lubricant during installation. Carbon is not affected by human body fluids, can be cleaned with solvents, and does not need to be oiled after steam sterilization, which is difficult to achieve with other materials.

[0006] Carbon plays an indispensable role in the fields of home appliances, automobiles, photovoltaic, etc. Carbon bearings or bushings are required for various home appliances such as dishwashers, beverage machines, coffee machines, and constant temperature hot water systems. Carbon graphite materials are also used as bearings or bushings in automotive electric water pumps, which are mainly applied to the cooling circulation systems and thermal management systems of new energy vehicles and high-end fuel vehicles. In the photovoltaic industry, the circulating pump in the photovoltaic pump system also requires carbon bearings or bushings.

[0007] However, traditional carbon graphite materials are porous materials. Due to the limitations of the use environment, bearings / bushings are in contact with or even immersed in water or other liquids all the time. The existence of pores will affect the strength of bearing / bushing products, thereby reducing the wear life of bearings / bushings. Therefore, if you want to improve the service life of bearings / bushings, you can consider the material replacement from the aspect of reducing its porosity.

[0008] Bakelite, also known as phenolic plastic, is abbreviated as PF in English. It has high mechanical strength, is tough, wear-resistant, dimensionally stable, and has good heat resistance and corrosion resistance. More importantly, bakelite belongs to the category of plastics and does not absorb water. All these conditions make it an excellent choice for sliding connection bearings / bushings.

[0009] Using carbon graphite material to compound bakelite powder as the raw material for carbon bearings, on the one hand, makes the porosity of the carbon bearing products extremely low, almost zero. On the other hand, the carbon material improves the thermal expansion and contraction characteristics of the bakelite material, enabling good dimensional stability of the products and meeting the production efficiency setting of single-piece molding.

[0010] The sliding bearings used in dishwashers need to come into contact with complex chemical components such as detergents, oil stains, and flavoring agents during operation. The carbon graphite composite bakelite material has good wear resistance, self-lubrication, and excellent chemical stability. By using the direct hot extrusion / press-to-size process, mass production can be achieved, significantly reducing production costs. Moreover, this carbon graphite composite bakelite material can pass the food contact material tests (National Food Safety Standards and US FDA standards) to meet the market usage requirements.

[0011] This material can also be used as bearings or bushings in micro DC brushless water pumps. Micro DC brushless water pumps are widely used in home appliance fields such as tea sets, coffee machines, water dispensers, and fish tanks. Since carbon graphite composite bakelite material is used as bearings, it has characteristics such as long service life and good sound insulation effect. According to different application requirements, the direct press-to-size process can be used to achieve mass production, and the dimensional accuracy fully meets the requirements, significantly reducing production costs.

[0012] For bearings or bushings used in automotive electronic water pumps, according to the material system and different needs, the direct press-to-size process can also be used to achieve mass production, and its dimensional accuracy can fully meet the market demand.

[0013] Photovoltaic pumps play a crucial role in solar water heating circulation systems. The main components of photovoltaic pumps include solar cell modules, controllers, and circulation pumps. Its working principle is that solar cell modules generate current under light, supply power to a DC motor through the controller to drive the pump to operate. At the same time, the collector is irradiated by light to raise the water temperature, and the hot water flows into the heat exchange coil through the circulation pump. The heat is transferred to the water in the storage tank through the tube wall of the heat exchange coil, raising the water temperature in the storage tank. The circulation pump is an assembly, including a DC motor and a water pump. The water pumps used in solar water heating circulation systems have relatively low power, and this carbon graphite composite bakelite material can be used as bearings or bushings. According to market needs, the direct press-to-size process can be used to achieve mass production, and its dimensional accuracy can fully meet the market demand.

[0014] Bearings or bushings are applied to dry friction and fluid friction, especially in liquids such as water, organic solutions, acids, and alkalis. The application of carbon bearings or bushings enables almost or completely frictionless losses for metal moving pairs. As long as the structure meets the requirements of low toughness and relatively low strength, the use of such carbon bearings or bushings has the outstanding advantages of low wear and remarkable chemical stability.

[0015] In addition, it should be noted that in addition to specifying the dimensional tolerances of carbon bearings or bushings, the appropriate material selection should also be determined according to the operating conditions of the pump and detailed operating parameters, such as temperature range, rotational speed, load, dry and wet operation, and the type of liquid used.

[0016] In terms of existing market applications, domestic manufacturers of carbon graphite materials are temporarily unable to develop such processes for mass supply. For machined carbon bearings or bushings, due to low processing efficiency, high processing costs, and the need for a large number of processing equipment for large quantities, their application and promotion are restricted.

[0017] With the development of society, people's pursuit of the quality of life is increasing. The applications of pumps in the fields of home appliances, automobiles, and photovoltaics will all show explosive growth. Developing and optimizing carbon bearings or bushings with a Press to Size process is the market trend.

[0018] In response to the needs of market development, the present invention provides a carbon bearing or bushing with a Press to Size process. Summary of the Invention

[0019] The primary object of the present invention is to provide a carbon bearing or bushing with a Press to Size process for the above-mentioned existing problems. The pump bearings or bushings of the present invention are manufactured by an injection molding process, with streamlined processes, high product strength, good wear resistance, high dimensional stability, and the characteristics of environmental protection. They can pass food contact material testing and meet national food safety standards and US FDA standards.

[0020] To achieve the object of the present invention, on the one hand, the present invention provides a carbon bearing or bushing, which includes matrix powder bakelite and modified additives. The modified additives are composed of graphite, carbon black, carbon fiber, glass fiber, and functional additives.

[0021] Among them, the bakelite is a phenolic plastic filled with wood powder, with a heat distortion temperature of above 190°C, preferably 190 - 230°C.

[0022] In particular, the flame retardant grade of the bakelite powder is 94V-0 / 0.5 to 1.6 mm, preferably 94V-0 / 1.5 mm; the molding shrinkage rate is ≤0.3 - 0.8%, preferably 0.6%.

[0023] In particular, the weight ratio of the matrix powder bakelite powder to the modified additive is (50 - 80):(30 - 60), and further preferably (50 - 60):(40 - 50).

[0024] In particular, the weight ratio of the graphite, carbon black, carbon fiber, glass fiber, and functional additive is (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8), preferably (10 - 20):(5 - 10):(5 - 10):(5 - 20):(2 - 8), and further preferably (16 - 17):5:5:(8 - 15):(6 - 8).

[0025] In particular, the graphite includes natural graphite and artificial graphite.

[0026] Natural graphite has advantages such as good electrical conductivity, thermal conductivity, and lubricity. Its particle size is 100 - 300 mesh, carbon content ≥99%, moisture content ≤0.5%, ash content ≤1.0%, and volatile content ≤1.0%.

[0027] Artificial graphite has excellent wear resistance, high strength, and good wettability. Its particle size is 200 - 500 mesh, carbon content ≥99.9%, moisture content ≤0.5%, and ash content ≤0.1%.

[0028] Carbon black is a black powdery substance formed by the incomplete combustion or pyrolysis of hydrocarbons in a strictly controlled process under a gas phase. Its main component is elemental carbon, and it contains a small amount of oxygen, hydrogen, sulfur, etc. In the present invention, N3 series carbon black is selected, with a nitrogen adsorption specific surface area of 100 ± 30 m2 / kg, ash content ≤0.5%, and residue on a 325 - mesh sieve ≤0.02%.

[0029] Carbon black has a high specific surface area, high blackness, good dispersibility, good strengthening effect, and low cost. It is a filler widely used in rubber, plastics, coatings, inks, and other fields. Its main function is to improve the strength, hardness, tensile properties, wear resistance, etc. of materials.

[0030] The carbon content of the carbon fiber powder is 90 - 95%. It is obtained by subjecting high - strength and high - modulus carbon fiber filaments to special technical surface treatment, grinding, microscopic discrimination, screening, and high - temperature drying to obtain equi - length cylindrical microparticles. Carbon fiber has good resistance to ultra - high temperature and fatigue in a non - oxidizing environment. Its specific heat and electrical conductivity are between non - metals and metals, with a small thermal expansion coefficient and anisotropy. The carbon fiber powder retains many excellent properties of carbon fiber, and has a small shape, pure surface, large specific surface area, and is easy to be wetted and uniformly dispersed.

[0031] Glass fiber is a kind of high-temperature resistant inorganic fiber, with a single filament diameter of 5 - 20 μm, preferably 9 μm, an average length of 20 - 100 μm, preferably 50 μm, an average aspect ratio of the glass fiber of 4 - 20:1, preferably 5.5:1, and a moisture content of < 0.2%.

[0032] The softening point of the glass fiber is close to 1700 °C and it can be used in an environment of 900 °C for a long time. It is heat-resistant, moisture-resistant, acid and alkali-resistant, wear-resistant and harmless to the human body, and can maintain a certain degree of flexibility under high-temperature conditions.

[0033] In particular, the weight ratio of the natural graphite to the artificial graphite is (40 - 60):(10 - 40), preferably (40 - 52):(16 - 24).

[0034] In particular, the functional additive includes talcum powder, titanium carbide and boron carbide.

[0035] In particular, the weight ratio of the talcum powder, titanium carbide and boron carbide is (2 - 7):(0 - 4):(0 - 4), preferably (2 - 5):(0.5 - 3):(0.5 - 3), further preferably (3 - 5):(1 - 2):(1 - 2), and even more preferably 3:1:1 or 5:2:2.

[0036] In particular, the particle size of the talcum powder is 400 - 600 mesh; the whiteness is 85 - 95%. Selecting talcum powder materials with finer particle size and higher whiteness, its main functions are to increase the stability of the product shape, help the materials to be homogenously mixed / kneaded and reduce the incorporation of impurities to avoid crack generation. In addition, talcum powder has many advantages such as lubricity, fire resistance, acid resistance, high melting point, chemical inactivity, softness, etc.;

[0037] In particular, the particle size of the titanium carbide is 0.8 - 3 μm; the purity is ≥ 99.9%. Titanium carbide (TiC) is a gray metallic face-centered cubic lattice solid, with the characteristics of high hardness, corrosion resistance and good thermal stability.

[0038] Especially, the particle size of the boron carbide is 1 - 2 μm; the purity is ≥ 99.0%. Boron carbide can be used as the second-phase particles to reinforce the composite material due to its advantages such as high strength, high hardness and good wettability with the matrix, and it is an excellent choice as a wear-resistant material.

[0039] On the other hand, the present invention provides a method for preparing a carbon bearing or a carbon bushing, including the following steps carried out in sequence:

[0040] 1) Prepare raw materials according to the following weight ratio

[0041] Matrix powder 50 - 80

[0042] Modified additive 30 - 60

[0043] 2) Mix the matrix powder and the modified additive, then conduct a crushing treatment to obtain raw material mixed granules with a particle size of 4 - 10 mm;

[0044] 3) Conduct an extrusion molding treatment on the raw material mixed granules to obtain a first - order semi - finished carbon bearing or bushing;

[0045] 4) Conduct a heat - curing treatment on the first - order semi - finished carbon bearing or bushing to obtain the product.

[0046] Among them, the matrix powder described in step 1) is bakelite powder.

[0047] In particular, the modified additive described in step 1) includes graphite, carbon black, carbon fiber, glass fiber, and functional additive.

[0048] In particular, the weight ratio of the graphite, carbon black, carbon fiber, glass fiber, and functional additive is (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8), preferably (10 - 20):(5 - 10):(5 - 10):(5 - 20):(2 - 8), and further preferably (16 - 17):5:5:(8 - 15):(6 - 8).

[0049] Among them, the graphite includes natural graphite and artificial graphite.

[0050] In particular, the weight ratio of the natural graphite and artificial graphite is (40 - 60):(10 - 40), preferably (40 - 52):(16 - 24).

[0051] Among them, the functional additive includes talcum powder, titanium carbide, and boron carbide.

[0052] In particular, the weight ratio of the talcum powder, titanium carbide, and boron carbide is (2 - 7):(0 - 4):(0 - 4), preferably (2 - 5):(0.5 - 3):(0.5 - 3), further preferably (3 - 5):(1 - 2):(1 - 2), and even more preferably 3:1:1 or 5:2:2 or 4:1:1.

[0053] Among them, the mixing treatment described in step 2) includes the following steps:

[0054] Mix the graphite, carbon black, carbon fiber, glass fiber, and functional additive evenly to form a modified additive; add the bakelite powder as the matrix powder, and then conduct a mixing treatment on the raw materials under heating conditions. After mixing evenly, cool to 0 - 50 °C; then conduct a crushing and screening treatment to obtain evenly mixed raw material mixed granules.

[0055] In particular, during the kneading process, the mixing time of the modifying additive is > 0.5 h, preferably 0.5 - 2 h; after adding bakelite powder, the first kneading process is carried out under the condition that the heating rate is 80 - 150 °C / h (preferably 120 °C / h) until the temperature of the raw material reaches 110 - 130 °C (preferably 120 °C); then, the second kneading process is carried out under the condition that the heating rate is 30 - 70 °C / h (preferably 50 °C / h) until the temperature of the raw material reaches 210 - 230 °C (preferably 220 °C); then the heating is stopped and the third kneading process is carried out, where the cooling rate of the third kneading process is 80 - 150 °C / h (preferably 90 - 120 °C / h, more preferably 120 °C / h), until the temperature of the raw material is lower than 100 °C, and then it is placed at room temperature and cooled to 0 - 50 °C.

[0056] In particular, the third kneading time is at least 1 h, preferably 1 - 2 h.

[0057] In particular, after taking out the raw material that has been kneaded in the third kneading process until the temperature is lower than 100 °C, it is placed at room temperature, evenly spread out, with a thickness ≤ 5 cm, and left standing for 5 - 10 h until the material is completely cooled to 0 - 50 °C.

[0058] Among them, the volume density of the first-order semi-finished carbon bearing or bushing obtained by the extrusion molding process in step 3) is 1.45 - 1.75 g / cm 3 , preferably 1.60 - 1.65 g / cm 3 .

[0059] Among them, the heat curing treatment in step 4) includes the following steps:

[0060] 4 - 1) First curing treatment

[0061] The first-order semi-finished carbon bearing or bushing is heated from room temperature to 80 °C, and then kept at 80 °C for at least 0.5 h to obtain the first-order cured carbon bearing or bushing;

[0062] 4 - 2) Second curing treatment

[0063] The first-order cured carbon bearing or bushing is further heated to 150 °C, and then kept at 150 °C for at least 3.5 h to obtain the second-order cured carbon bearing or bushing;

[0064] 4 - 3) Third curing treatment

[0065] The second-order cured carbon bearing or bushing is further heated to 220 °C, and then kept at 220 °C for at least 4 h to obtain the third-order cured carbon bearing or bushing;

[0066] 4-4) Fourth curing treatment

[0067] Cool the third-stage cured carbon bearing or bushing from 220°C to 150°C at a cooling rate of 20 - 25°C / h, and then keep the temperature at 150°C for at least 0.5 h to obtain the fourth-stage cured carbon bearing or bushing;

[0068] 4-5) Fifth curing treatment

[0069] Cool the fourth-stage cured carbon bearing or bushing from 150°C to 80°C at a cooling rate of at least 35°C / h, and then continue to cool it to below 80°C to obtain the second-stage semi-finished carbon bearing or bushing.

[0070] Among them, in step 4-1), the heating rate is 36.5 - 110°C / h; the heating time is 0.5 - 1.5 h; the holding time is preferably 0.5 - 2.0 h; in step 4-2), the heating rate is 15.5 - 20°C / h; the heating time is preferably 3.5 - 4.5 h; the holding time is preferably 0.5 - 2.0 h; in step 4-3), the heating rate is 7.7 - 15.5°C / h; the heating time is preferably 4.5 - 9.0 h; the holding time is preferably 4.0 - 8.0 h; in step 4-4), the cooling rate is 20 - 25°C / h; the cooling time is preferably 2.8 - 3.5; the holding time is preferably 0.5 - 2.0 h; in step 4-5), the cooling rate is 35 - 46.6°C / h; the cooling time is preferably 1.5 - 2.0.

[0071] Perform thermal curing treatment to ensure the thermal stability of the product.

[0072] In particular, it further includes step 5) post-treating the product after thermal curing treatment, that is, deburring, chamfering, and polishing the end face of the thermally cured product.

[0073] In particular, it further includes step 6) performing finishing treatment on the post-treated product, that is, polishing the inner hole of the product with high requirements for inner hole size to obtain a finished carbon bearing or bushing that meets the dimensional requirements of the customer's drawing.

[0074] Another aspect of the present invention provides a carbon bearing or carbon bushing prepared according to the above method.

[0075] In particular, the temperature of the mixing treatment is 160 - 230°C; the time of the mixing treatment is 2 - 6 h.

[0076] In particular, the maximum temperature of the thermal curing treatment is 150 - 250°C.

[0077] In particular, the total time of the thermal curing treatment is 10 - 30 h.

[0078] In particular, the following table thermal curing treatment process curve can be preferably adopted, and the semi-finished carbon bearing or bushing in the first stage is placed in an oven for thermal curing treatment.

[0079]

[0080] Among them, the end face of the semi-finished carbon bearing or bushing in the second stage is deburred, chamfered, and polished to obtain a carbon bearing or bushing product that can be supplied in batches.

[0081] In particular, if the inner hole size of the product has high requirements, the inner hole of the product also needs to be polished to obtain a finished carbon bearing or bushing that meets the dimensional requirements of the customer's drawing.

[0082] Prepared by the method of the present invention: the raw material matrix bakelite powder is uniformly mixed with additives such as graphite powder and carbon powder to make raw materials, or directly purchase and customize special bakelite composite raw materials; test the physical and mechanical properties and thermal expansion properties of the raw materials, including bulk density, Shore hardness, compressive strength, and linear thermal expansion coefficient, and collect data before the injection mold is opened, and then evaluate the mold size; inject the raw materials to obtain semi-finished carbon bearings or bushings; perform heat treatment on the product after injection molding to ensure the stability of the product; perform deburring, chamfering, and polishing on the end face of the semi-finished product, and products with high requirements for the inner hole size may also need to be polished on the inner hole to obtain finished carbon bearings or bushings that meet the dimensional requirements of the customer's drawing.

[0083] The advantages and beneficial technical effects of the present invention are as follows:

[0084] 1. The raw material composition of the present invention is reasonable and the formula is scientific. The use of bakelite material has high hardness, good toughness, high stability and chemical corrosion resistance, and can meet the use requirements of high strength and wear resistance of carbon bearings or bushings.

[0085] 2. Graphite, carbon fiber, and glass fiber are selected as raw materials in the raw materials of the present invention. The materials prepared by using such raw materials have high strength, wear resistance and good lubrication performance of the product, do not damage the ceramic structure and the steel structure counter grinding parts. At the same time, the carbon material is introduced into the bakelite material system, and the prepared composite material has a relatively controllable thermal expansion coefficient of the product, and can realize the setting of small product size variability, so as to realize single product molding.

[0086] 3. High-hardness materials such as titanium carbide and boron carbide are added to the raw materials of the present invention, which improves the wear resistance of the product. At the same time, it can microscopically improve the uniformity of the composite material of the present invention and improve the dimensional stability of the composite material of the present invention.

[0087] 4. The carbon bearings or bushings of the present invention are particularly suitable for use in small power pumps such as dishwasher pumps and other household appliances.

[0088] 5. The carbon bearings or bushings of the present invention are manufactured by an injection molding process, with extremely streamlined processes. The products have extremely low porosity, high strength, good wear resistance, high dimensional stability, and are environmentally friendly. They can pass food contact material tests and meet national food safety standards and US FDA standards. They are particularly suitable for various household appliance pumps such as dishwashers, beverage machines, coffee machines, constant temperature hot water systems, and parts for small power auxiliary motors of new energy vehicles. Detailed implementation manners

[0089] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description progresses. However, these embodiments are merely exemplary and do not constitute any limitation to the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and forms of the technical solutions of the present invention without departing from the spirit and scope of the present invention, and these modifications and substitutions all fall within the protection scope of the present invention.

[0090] The raw materials of the present invention, such as natural graphite, artificial graphite, carbon black, carbon fiber, glass fiber, talcum powder, titanium carbide and boron carbide, and bakelite powder, are all commercially available products.

[0091] In the specific implementation manner of the present invention, Changchun bakelite powder commercially available is taken as an example for illustration, and other bakelite powders are also applicable to the present invention, such as Sumitomo bakelite powder.

[0092] The heat distortion temperature of the bakelite powder used in this embodiment reaches 190 - 230 °C, the flame retardant grade is 94V - 0 / 1.5 mm, and the molding shrinkage rate is 0.6%. Other bakelite powders with a heat distortion temperature above 190 °C, a flame retardant grade of 94V - 0 / 0.5 - 1.6 mm, and a molding shrinkage rate of 0.3 - 0.8% are also applicable to the present invention.

[0093] Example 1

[0094] 1. Prepare materials according to the following weight ratio (kg):

[0095] Matrix powder bakelite powder 60

[0096] Modified additive 40

[0097] Among them, the modified additive includes graphite, carbon black, carbon fiber, glass fiber, and functional additive. The weight ratio of graphite, carbon black, carbon fiber, glass fiber, and functional additive is 16:5:5:8:6 (usually: (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8)); 16 kg of graphite, 5 kg of carbon black, 5 kg of carbon fiber, 8 kg of glass fiber, and 6 kg of functional additive; among them:

[0098] The graphite consists of natural graphite and artificial graphite, and the weight ratio of natural graphite to artificial graphite is 40:24

[0099] (i.e., 10 kg of natural graphite and 6 kg of artificial graphite); the weight part ratio of natural graphite to artificial graphite is usually (40 - 60):(10 - 40);

[0100] The functional additives are talcum powder, titanium carbide and boron carbide, and the ratio of talcum powder, titanium carbide and boron carbide is 3:1:1 (usually (2 - 7):(0 - 4):(0 - 4), preferably (2 - 5):(0.5 - 3):(0.5 - 3)), that is, 3.6 kg of talcum powder, 1.2 kg of titanium carbide and 1.2 kg of boron carbide;

[0101] In the specific embodiment of the present invention, the raw materials with the following characteristics are taken as an example: the particle size of natural graphite is 100 - 300 mesh, the carbon content is ≥99%, the moisture content is ≤0.5%, the ash content is ≤1.0%, and the volatile content is ≤1.0%; the particle size of artificial graphite is 200 - 500 mesh, the carbon content is ≥99.9%, the moisture content is ≤0.5%, and the ash content is ≤0.1%; the carbon black is selected from the N3 series, the nitrogen adsorption specific surface area is 100 ± 30 m2 / kg, the ash content is ≤0.5%, and the residue on 325 - mesh sieve is ≤0.02%; the carbon content of carbon fiber powder is 90 - 95%; the single - filament diameter of glass fiber is 5 - 20 μm (preferably 9 μm); the average length is 20 - 100 μm (preferably 50 μm); the average aspect ratio of glass fiber is 4 - 20:1 (preferably 5.5:1); the moisture content is <0.2%; the particle size of talcum powder is 400 - 600 mesh; the whiteness is 85 - 95%; the particle size of titanium carbide is 0.8 - 3 μm; the purity is ≥99.9%; the particle size of boron carbide is 1 - 2 μm; the purity is ≥99.0%.

[0102] 2. Kneading treatment

[0103] 2 - 1. Place natural graphite, artificial graphite, carbon black, carbon fiber, glass fiber and functional additives in a kneading pot, turn on the rotation switch of the kneading pot, and conduct a mixing treatment to obtain a modified additive;

[0104] 2 - 2. After mixing for 0.5 h (usually >0.5 h, preferably 0.5 - 2 h), add the matrix powder bakelite powder, and turn on the heating switch. Under the condition that the heating rate is 120℃ / h (usually 80 - 150℃ / h), conduct the first kneading treatment until the temperature of the raw materials reaches 120℃ (usually 110 - 130℃); the first kneading treatment makes the temperature of the raw materials rise evenly to 120℃ (usually 110 - 130℃) in 1 h;

[0105] 2-3. Continue heating and raising the temperature. Under the condition that the heating rate is 50 °C / h (usually 30-70 °C / h), carry out the second kneading treatment until the temperature of the raw material reaches 220 °C (usually 210-230 °C); the second kneading treatment enables the bakelite powder to uniformly adhere to the modified additive, and the second kneading treatment raises the temperature of the raw material to 220 °C (usually 210-230 °C) uniformly within 2 h;

[0106] 2-4. Then stop heating and continue the third kneading treatment and granulation until the temperature is lower than 80 °C (usually lower than 100 °C) to obtain the kneaded raw material, where the third kneading treatment takes 1.5 h (usually 1-2 h), and the cooling rate of the third kneading treatment is 93.3 °C / h (usually 80-150 °C / h, preferably 90-120 °C / h);

[0107] After taking out the kneaded raw material, place it at room temperature, spread it out evenly with a thickness ≤ 5 cm, and let it stand for 5-10 h until the material is completely cooled to 0-50 °C, paying attention to moisture and dust prevention to obtain the raw material mixture.

[0108] 3. Crushing - screening treatment

[0109] Carry out crushing treatment on the raw material mixture and screening treatment on the crushed material to obtain raw material mixed granules with a particle size of 4-10 mm.

[0110] 4. Extrusion molding treatment

[0111] Squeeze the raw material mixed granules into an extrusion molding die to carry out extrusion molding treatment to obtain a first-order semi-finished carbon bearing or bushing with a bulk density of 1.60 g / cm 3 ;

[0112] 5. Thermal curing treatment

[0113] Place the first-order semi-finished carbon bearing or bushing in an oven and start from room temperature (20 °C) to carry out thermal curing treatment using the thermal curing curve shown in Table 1 to obtain a second-order semi-finished carbon bearing or bushing;

[0114] Table 1 Thermal curing treatment temperature control curve

[0115]

[0116]

[0117] 6. Post-treatment

[0118] Carry out end face deburring, chamfering, and polishing treatment on the second-order semi-finished carbon bearing or bushing to obtain a finished carbon bearing or bushing that meets the dimensional requirements of the customer's drawing;

[0119] 7. Finishing treatment

[0120] If very high requirements are imposed on the product dimensions, it may be necessary to perform machining operations such as internal turning, polishing, and end face polishing on the semi-finished carbon bearings or bushings in these two stages to produce finished carbon bearings or bushings that meet the dimensional requirements of the customer's drawings, which are the carbon bearing or bushing products that can be supplied in batches;

[0121] For the obtained carbon bearing or bushing products, according to the method of JB / T8133.14 - 2013 (Test methods for physical and chemical properties of carbonaceous products - Part 14: Bulk density), the bulk density of the carbon bearing or bushing material is measured using the Archimedes principle;

[0122] According to the method of JB / T8133.4 - 2013 (Test methods for physical and chemical properties of carbonaceous products - Part 4: Shore hardness), the Shore hardness of the carbon bearing or bushing material is measured using an HS - 19CTV type hardness tester;

[0123] According to the method of JBT 8133.8 - 2013 (Test methods for physical and chemical properties of carbonaceous products - Part 8: Compressive strength), the compressive strength of the carbon bearing or bushing material is measured;

[0124] According to the method of JB / T8133.15 - 2013 (Test methods for physical and chemical properties of carbonaceous products - Part 15: Porosity), the open porosity of the carbon bearing or bushing material is measured; the results are shown in Table 2.

[0125] Using an MHS - 200 type high - speed current - carrying friction and wear testing machine, the friction coefficient and wear rate of the carbon bearing or bushing material are tested, and the test results are shown in Table 3.

[0126] Example 2

[0127] 1. Prepare materials according to the following weight ratio (kg):

[0128] Matrix powder Bakelite powder 50

[0129] Modified additive 50

[0130] Among them, the modified additive includes graphite, carbon black, carbon fiber, glass fiber, and functional additive. The weight ratio of graphite, carbon black, carbon fiber, glass fiber, and functional additive is 17:5:5:15:8 (usually: (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8)); 17 kg of graphite, 5 kg of carbon black, 5 kg of carbon fiber, 15 kg of glass fiber, and 8 kg of functional additive; among them:

[0131] Graphite is composed of natural graphite and artificial graphite, and the weight ratio of natural graphite to artificial graphite is 52:16

[0132] (i.e., 13 kg of natural graphite and 4 kg of artificial graphite); the weight ratio of natural graphite to artificial graphite is usually (40 - 60):(10 - 40);

[0133] The functional additives are talcum powder, titanium carbide, and boron carbide, and the ratio of talcum powder, titanium carbide, and boron carbide is

[0134] 4.8:1.6:1.6 (usually (2 - 7):(0 - 4):(0 - 4)), 4.8 kg of talcum powder, 1.6 kg of titanium carbide, and 1.6 kg of boron carbide.

[0135] 2. Kneading treatment

[0136] Except that the bakelite powder is added after the mixing time for preparing the modified additive is 2 h; the heating rate during the first kneading treatment is 150 °C / h (usually 80 - 150 °C / h); the second kneading heating is carried out after the first kneading temperature reaches 130 °C (usually 110 - 130 °C); the heating rate during the second kneading treatment is 70 °C / h (usually 30 - 70 °C / h); the heating is stopped after the second kneading temperature reaches 230 °C (usually 210 - 230 °C); the cooling rate of the third kneading is 120 °C / h (usually 80 - 150 °C / h), the rest is the same as in Example 1.

[0137] 3. Crushing - screening treatment

[0138] The same as in Example 1.

[0139] 4. Extrusion molding treatment

[0140] Except that the bulk density of the first - order semi - finished carbon bearing or bushing is 1.65 g / cm 3 otherwise, the rest is the same as in Example 1.;

[0141] 5. Thermal curing treatment

[0142] Starting from room temperature (30 °C), thermal curing treatment is carried out according to the temperature described in Table 4 to obtain the second - order semi - finished carbon bearing or bushing;

[0143] Table 4 Thermal curing treatment temperature control curve

[0144]

[0145]

[0146] 6. Post - treatment

[0147] The same as in Example 1.

[0148] 7. Precision machining treatment

[0149] The same as in Example 1.

[0150] The bulk density, Shore hardness, compressive strength, and porosity of carbon bearings or bushings prepared according to JB / T8133.14-2013 (Test Methods for Physical and Chemical Properties of Electrical Carbon Products) were measured; the wear resistance coefficient and wear rate of carbon bearings or carbon bushings were measured using an MHS-200 high-speed current-carrying friction and wear testing machine. The measurement results are shown in Tables 2 and 3 respectively.

[0151] Example 3

[0152] 1. Prepare materials according to the following weight ratio (kg):

[0153] Matrix powder, bakelite powder 65

[0154] Modified additive 54

[0155] Among them, the modified additive includes graphite, carbon black, carbon fiber, glass fiber, and functional additive. The weight ratio of graphite, carbon black, carbon fiber, glass fiber, and functional additive is 20:8:5:15:6 (usually (10-30):(5-20):(0-15):(0-50):(2-8)); 20 kg of graphite, 8 kg of carbon black, 5 kg of carbon fiber, 15 kg of glass fiber, and 6 kg of functional additive; among them:

[0156] Graphite consists of natural graphite and artificial graphite, and the weight ratio of natural graphite to artificial graphite is 50:10

[0157] (that is, 16.7 kg of natural graphite and 3.3 kg of artificial graphite); the weight ratio of natural graphite to artificial graphite is usually (40-60):(10-40);

[0158] The functional additive is talc powder, titanium carbide, and boron carbide, and the ratio of talc powder, titanium carbide, and boron carbide is 5:2:2 (usually (2-7):(0-4):(0-4)), 3.34 kg of talc powder, 1.33 kg of titanium carbide, and 1.33 kg of boron carbide.

[0159] 2. Kneading treatment

[0160] Except that the mixing time for preparing the modified additive is 1 h and then bakelite powder is added; the heating rate during the first kneading treatment is 80 °C / h (usually 80-150 °C / h); after the first kneading temperature reaches 110 °C (usually 110-130 °C), the second kneading heating is carried out; the heating rate during the second kneading treatment is 30 °C / h (usually 30-70 °C / h); after the second kneading temperature reaches 210 °C (usually 210-230 °C), the heating is stopped; the cooling rate during the third kneading is 80 °C / h (usually 80-150 °C / h), the rest is the same as in Example 1.

[0161] 3. Crushing - screening treatment

[0162] Same as Example 1

[0163] 4. Extrusion molding treatment

[0164] Except that the bulk density of the first - order semi - finished carbon bearing or bushing is 1.58 g / cm 3 the rest is the same as Example 1;

[0165] 5. Thermal curing treatment

[0166] Starting from room temperature (25 °C), perform thermal curing treatment according to the temperature described in Table 5 to obtain the second - order semi - finished carbon bearing or bushing;

[0167] Table 5 Thermal curing treatment temperature control curve

[0168]

[0169] 6. Post - treatment

[0170] Same as Example 1

[0171] 7. Precision machining treatment

[0172] Same as Example 1

[0173] Measure the bulk density, Shore hardness, compressive strength, and porosity of the prepared carbon bearing or bushing products according to JB / T8133.14 - 2013 (Test methods for physical and chemical properties of electrical carbon products); use the MHS - 200 type high - speed current - carrying friction and wear testing machine to measure the wear resistance coefficient and wear rate of the carbon bearing or carbon bushing. The measurement results are shown in Tables 2 and 3 respectively.

[0174] Example 4

[0175] 1. Prepare materials according to the following weight ratio (kg):

[0176] Matrix powder Bakelite powder 70

[0177] Modified additive 50

[0178] Among them, the modified additive includes graphite, carbon black, carbon fiber, glass fiber, and functional additive. The weight ratio of graphite, carbon black, carbon fiber, glass fiber, and functional additive is 14:10:10:10:6 (usually: (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8)); 14 kg of graphite, 10 kg of carbon black, 10 kg of carbon fiber, 10 kg of glass fiber, and 6 kg of functional additive; among them:

[0179] The graphite consists of natural graphite and artificial graphite, and the weight ratio of natural graphite to artificial graphite is 50:20

[0180] (i.e., 10 kg of natural graphite and 4 kg of artificial graphite); the weight part ratio of natural graphite to artificial graphite is usually (40 - 60):(10 - 40);

[0181] The functional additives are talcum powder, titanium carbide and boron carbide, and the proportion of talcum powder, titanium carbide and boron carbide is 4:1:1 (usually (2 - 7):(0 - 4):(0 - 4)), 4 kg of talcum powder, 1 kg of titanium carbide and 1 kg of boron carbide.

[0182] 2. Kneading treatment

[0183] Same as Example 1.

[0184] 3. Crushing - screening treatment

[0185] Same as Example 1.

[0186] 4. Extrusion molding treatment

[0187] Except that the bulk density of the first - order semi - finished carbon bearing or bushing is 1.58 g / cm 3 otherwise, the rest is the same as Example 1.;

[0188] 5. Thermal curing treatment

[0189] Starting from room temperature (25 °C), carry out thermal curing treatment according to the temperature described in Table 6 to obtain the second - order semi - finished carbon bearing or bushing;

[0190] Table 6 Thermal curing treatment temperature control curve

[0191]

[0192] 6. Post - treatment

[0193] Same as Example 1.

[0194] 7. Finishing treatment

[0195] Same as Example 1.

[0196] Measure the bulk density, Shore hardness, compressive strength, and porosity of the prepared carbon bearing or bushing products according to JB / T8133.14 - 2013 (Test methods for physical and chemical properties of electrical carbon products); use an MHS - 200 type high - speed current - carrying friction and wear testing machine to measure the wear resistance coefficient and wear rate of the carbon bearing or carbon bushing, and the measurement results are shown in Tables 2 and 3 respectively.

[0197] Control example

[0198] The carbon bearing or bushing MCI320 / T for dishwashing machine pumps imported from Italy was used as a control example.

[0199] According to JB / T8133.14 - 2013 (Test Methods for Physical and Chemical Properties of Electrical Carbon Products), the bulk density, Shore hardness, compressive strength, and porosity of the products in the control example were measured; the wear resistance coefficient and wear rate of the carbon bearing or carbon bushing in the control example were measured using an MHS - 200 high - speed current - carrying friction and wear testing machine. The measurement results are shown in Tables 2 and 3 respectively.

[0200] Table 2 Physical and Mechanical Property Test Results of Carbon Bearing or Bushing Materials

[0201]

[0202] The test results in Table 2 show that: the bulk density of the carbon bearing or bushing prepared by the present invention is 1.50 - 1.70 g / cm 3 , the Shore hardness is about 70 HSD, the compressive strength is > 100 MPa, and the open porosity is extremely low, almost 0%.

[0203] The manufacturing process of the carbon bearing or bushing prepared by the present invention is simple. Compared with the control example of imported materials, the bulk density of the materials prepared by the present invention is lower than that of the control example, the Shore hardness is the same as that of the control example, but the compressive strength index is much higher than that of the control example, and the porosity index is also lower than that of the control example. The carbon bearing or bushing prepared by the present invention has been verified by the market and is suitable for use as a carbon bearing or bushing for pumps.

[0204] Table 3 Friction and Wear Test Results of Carbon Bearing or Bushing Materials

[0205]

[0206] It can be seen from the results in Table 3 that: the friction coefficient of the carbon bearing or bushing materials prepared by the present invention is lower than that of the imported materials in the control example, and the material wear rate is low. Thus, it can be seen that the carbon bearing or bushing materials prepared by the present invention have excellent wear resistance, and compared with the imported materials in the control example, they have better wear resistance and a simpler process.

[0207] The above - mentioned embodiments of the present invention are merely exemplary and do not constitute any limitation to the scope of the present invention. Those skilled in the art should understand that without departing from the spirit and scope of the present invention, details and forms of the technical solution of the present invention can be modified or replaced, but these modifications and replacements all fall within the protection scope of the present invention.

Claims

1. A carbon bearing or carbon bushing, characterized in that, It includes matrix powder bakelite powder and modified additives, where the modified additives are composed of graphite, carbon black, carbon fiber, glass fiber, and functional additives.

2. The carbon bearing or carbon bushing according to claim 1, characterized in that, The functional additives include talcum powder, titanium carbide, and boron carbide.

3. A method for preparing a carbon bearing or a carbon bushing, characterized in that, It includes the following steps carried out in sequence: 1) Prepare raw materials according to the following weight ratio Matrix powder 50 - 80 Modified additives 30 - 60 2) Mix and knead the matrix powder and modified additives, and then carry out crushing treatment to obtain raw material mixed granules with a particle size of 4 - 10 mm; 3) Carry out extrusion molding treatment on the raw material mixed granules to obtain a first-order semi-finished carbon bearing or bushing with a bulk density of 1.45 - 1.75 g / cm3; 4) Carry out heat curing treatment on the first-order semi-finished carbon bearing or bushing, and that's it.

4. The method according to claim 3, characterized in that, In step 1), the matrix powder is bakelite powder.

5. The method according to claim 3 or 4, characterized in that, In step 1), the modified additives include graphite, carbon black, carbon fiber, glass fiber, and functional additives.

6. The method according to claim 5, characterized in that, The weight ratio of the graphite, carbon black, carbon fiber, glass fiber, and functional additives is (10 - 30):(5 - 20):(0 - 15):(0 - 50):(2 - 8), preferably (10 - 20):(5 - 10):(5 - 10):(5 - 20):(2 - 8), and further preferably (16 - 17):5:5:(8 - 15):(6 - 8).

7. The method according to claim 5, characterized in that The graphite includes natural graphite and artificial graphite.

8. The method according to claim 5, characterized in that, The functional additives include talcum powder, titanium carbide, and boron carbide.

9. The method according to claim 5 or 6, characterized in that, The heat curing treatment in step 4) is carried out according to the following steps: 4 - 1) First curing treatment Heat the first-order semi-finished carbon bearing or bushing from room temperature to 80°C, and then keep the temperature at 80°C for at least 0.5 h to obtain the first-order cured carbon bearing or bushing; 4 - 2) Second curing treatment Continue to heat the first-order cured carbon bearing or bushing to 150°C, and then keep the temperature at 150°C for at least 3.5 h to obtain the second-order cured carbon bearing or bushing; 4 - 3) Third curing treatment Continue to heat the second-order cured carbon bearing or bushing to 220°C, and then keep the temperature at 220°C for at least 4 h to obtain the third-order cured carbon bearing or bushing; 4 - 4) Fourth curing treatment Cool the third-order cured carbon bearing or bushing from 220°C to 150°C at a cooling rate of 20 - 25°C / h, and then keep the temperature at 150°C for at least 0.5 h to obtain the fourth-order cured carbon bearing or bushing; 4 - 5) Fifth curing treatment Cool the fourth-order cured carbon bearing or bushing from 150°C to 80°C at a cooling rate of at least 35°C / h, and then discharge the material at a temperature lower than 80°C to obtain the second-order semi-finished carbon bearing or bushing.

10. A carbon bearing or carbon bushing, characterized in that, Prepared by the method according to any one of claims 3 - 9.

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