JPS637572B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a sliding material containing carbon graphite as a main component. [Prior Art] As a sliding material used for bearings and mechanical sealing, a carbon graphite-resin sliding material made by hardening carbon graphite with a phenol resin or the like is known. Traditionally, silica has been added to this carbon graphite-resin sliding material.
Inorganic powders such as alumina and solid lubricants such as molybdenum disulfide and fluororesin powders are added to improve friction properties such as friction coefficient and wear resistance. As a result of intensive research into this carbon graphite-resin-based sliding material, the inventors of the present invention found that using alumina powder with gamma-alumina as the inorganic powder as the inorganic powder compared to sliding materials using conventional alpha alumina. It was discovered that the wear of the mating material and the wear of the self itself can be reduced. The present invention was completed based on this discovery. [Object of the Invention] An object of the present invention is to provide a carbon graphite-alumina-resin-based sliding material that has excellent abrasion resistance on both the mating material and itself. [Structure of the Invention] The sliding material of the present invention has carbon graphite, alumina powder, and a synthetic resin binder as main components, and the alumina powder is an alumina mainly composed of gamma alumina. This is a special sliding material. [Detailed Description of the Structure of the Invention] Carbon graphite, which is one of the constituent elements of the sliding material of the present invention, mainly functions to reduce the frictional force during sliding, and is a component of the sliding material of the present invention. Becomes the main ingredient. This carbon graphite is preferably completely graphitized, but it is also possible to use carbon graphite that is not necessarily completely graphitized. A perfect graphite crystal has a lattice spacing of 3.354 angstroms in its (002) direction. As the carbon graphite of the present invention, those having the above-mentioned interplanar spacing of about 3.500 angstroms can be used. Preferably, carbon graphite having a lattice spacing in the range of 3.354 to 3.410 angstroms is used. As carbon graphite, both natural graphite and artificial graphite can be used. As the natural graphite, earthy graphite, scaly graphite, scaly graphite, and blocky graphite can be used. As artificial graphite,
Anthracite, pitch, etc. heated to high temperature in an arc furnace can be used. The particle size of carbon graphite is 0.5~
A range of 200μ is desirable. The reason for this is that sufficient frictional properties and sufficient bonding strength with the resin can be obtained. In particular, a range of 2 to 100μ is desirable. The proportion of carbon graphite varies depending on the amount of alumina and sliding conditions, but it is preferably in the range of 40 to 70% by weight, taking the total as 100%.
This is because if it is less than 40%, the friction properties will deteriorate, and if it is more than 70%, the strength will be reduced. In particular, the proportion of carbon graphite is preferably in the range of 50 to 60%. The alumina powder mainly bears the sliding load with the mating material. The alumina powder is mainly gamma (γ) alumina powder. By "mainly" means that gamma alumina, which accounts for more than 90% of the alumina powder, plays an important role. Gamma-alumina has a spinel structure, some have poor crystallinity, and the lattice constant varies depending on the manufacturing method (a = 7.75 to 8.08 angstroms). Alumina powder usually means alpha (a) alumina powder. The present inventor has discovered that wear resistance can be improved by using an alumina powder mainly composed of gamma alumina instead of alpha alumina. That is, the hardness of alpha alumina is usually 1500 to 2000 Hv, which is very hard. In contrast, the hardness of gamma-alumina is typically 600 to 1000 Hv. Therefore, the hardness of gamma alumina is considerably lower than that of alpha alumina. This low hardness gamma alumina is thought to be a factor in improving the wear resistance of the sliding material and reducing the wear of the mating material. Here, the proportion of alumina powder mainly composed of gamma alumina is 2 to 30%.
Good range. If it is less than 2%, the sliding surface exposure rate of gamma-alumina is too small to be effective, and if it exceeds 30%, the bonding force with the resin will be insufficient, causing problems in terms of strength and wear. becomes. Other than gamma alumina, 11Al ₂ O ₃ Na ₂ O,
It can be used even if it contains rho (ρ), chi (χ), eta (η), or delta (δ) alumina.
Although not preferred, a small amount of alpha alumina of 10% or less may be included in the alumina powder. The synthetic resin binder functions to bind carbon graphite and alumina powder. A thermosetting resin is desirable as the synthetic resin binder. As the thermosetting resin, phenolic resin, epoxy resin, melamine resin, urea resin, polyimide resin, polyamideimide resin, epoxy-modified phenolic resin, melamine-modified phenolic resin, etc. can be used. This is because these resins generally have high heat resistance, excellent toughness, and strong bonding properties. Depending on usage conditions, thermoplastic resins such as fluororesin, polyacetal resin, and nylon resin may be used. In addition to the above components, 0.5 to 15 wt% of a solid lubricant and/or lubricating oil, and 5 to 25 wt% of a strength reinforcing material and an anti-wear material can be used, if necessary. Solid lubricants include molybdenum distributide, lead,
Examples include boron nitride, tungsten indium disulfide, tin, and fluororesin powder. Lubricating oils include silicone oil, heat-resistant synthetic oil, olefin oil, paraffin oil, and general mineral oil. As the strength reinforcing agent, reinforcing fibers such as carbon fibers and glass fibers and glass beads can be used, and as the anti-wear agent, granular materials such as SiO ₂ having high hardness and large particle size can be used. Next, a typical manufacturing method of the sliding material of the present invention will be explained. First, the required amounts of carbon graphite, alumina powder, and synthetic resin binder are blended and mixed. If a solid lubricant or the like is used, this should also be mixed. Mixing can be carried out in a conventional mixer. Next, knead. The kneading is performed to mix carbon graphite powder, alumina powder, synthetic resin binder and other additives.
In this case, it is better to use Hottrol or Conida. The kneading temperature is preferably 80 to 120°C. Next, pulverization is performed. In this case, it is recommended to use a crusher. The particle size of the powder after pulverization is preferably in the range of 1.4 mm or less. Next, the powder produced as described above is charged into a mold and molded into a predetermined shape. In this case compression molding or injection molding can be carried out.
In the case of compression molding, the pressure is preferably 200 kg/cm ² , the temperature is 155° C., and the pressing time is 3 minutes. After forming into a predetermined shape, the surface of the sliding material is cut so that it can serve as an impulse surface. Other manufacturing methods are as follows. First, carbon graphite, alumina powder, and a synthetic resin binder are blended in predetermined amounts and mixed and kneaded to form a resin paste. Next, the resin paste is applied to the surface of another member that will become the base of the sliding material. Then, this resin paste is solidified at room temperature or by heating or other methods, thereby fixing the sliding material to the member. In this case, if irregularities are formed in advance on the surface of the above-described other member, the resin paste serving as the sliding material will be reliably fixed to the aforementioned member due to the anchoring effect of the irregularities. [Effects of the Invention] The sliding material of the present invention has extremely little aggressiveness against mating materials. For this reason, the mating material hardly wears out due to sliding. Furthermore, the sliding material itself of the present invention has excellent wear resistance. The wear coefficient is also about the same as that of conventional carbon graphite-alumina resin-based sliding materials. [Experimental Example] First, samples were prepared with the compositions shown in No. 1 to No. 23 in Table 1. When producing, the particle size
Carbon graphite with a particle size of 80 μm or less, gamma alumina powder with a particle size of 10 μm or less, a phenol resin, an epoxy resin, and a polyimide resin were mixed and kneaded. Artificial graphite powder was used as carbon graphite. Mixing was carried out using a Fenher mixer, and mixing was carried out using a hottrol. Next, a sample was prepared by pressure molding at 155° C. for 3 minutes under a pressure of 200 kg/cm ² . The shape of the sample is a disk, with an outer diameter of 21 mm, an inner diameter of 16 mm, and a thickness of 7 mm. Furthermore, a comparative sample containing alpha alumina but not gamma alumina was also prepared. As shown in No. 24 to No. 31 in Table 1, the comparative samples were made of phenolic resin and artificial graphite powder of 40 to 70 μm in particle size of 80 μm or less.
%, the composition is 12-30% alpha alumina with a particle size of 10μ or less. No.1 to No.31 prepared as above
The friction coefficient was investigated for each sample. in this case,
A mating material is attached to a rotatable round shaft, the circular end face of a cylindrical sample is brought into close contact with this mating material, and with the specimen fixed, the mating material is rotated by the round shaft for a predetermined period of time. The sample and the mating material were made to slide. The sliding conditions are as follows. Testing machine: Ring-ring friction and wear tester Load applied to sample: 5Kg Rotation speed: 0.2m/sec Atmosphere: Underwater Rotation time: 1 hour Compatible material: Alumina ceramic ring (surface roughness is 0.3Ra or less) Coefficient of friction The test results investigated are shown in Table 2. Compare No. 1 and No. 24, which have the same proportion of phenolic resin and the same proportion of carbon graphite. In the case of No. 1 containing 2% gamma-alumina, the friction coefficient was 0.39. On the other hand, in the case of No. 24 containing 2% alpha alumina, the friction coefficient was 0.41, which was larger than that of No. 1. Furthermore, with No.3
Comparing with No. 25, gamma alumina is 9%
In the case of No. 3, the friction coefficient was 0.31. On the other hand, in the case of No. 25 containing 9% alpha alumina, the friction coefficient was 0.37, which was larger than that of No. 3. In addition, No. 8 containing 19% gamma alumina,
When compared with No. 26 containing 19% alpha alumina, it was 0.34 for No. 8 and 0.40 for No. 26, which were larger than No. 8. As shown in Table 2, the friction coefficients of the invention products No. 1 to No. 23 are lower than those of the comparative examples No. 24 to No. 31. Next, the wear of the mating material and the wear of the sample were investigated. In this test, in the same way as described above, the mating material was attached to a rotatable round shaft, the ring-shaped end surface of the cylindrical sample was sealed to the mating material, and the mating material was held by the round shaft while the sample was fixed. The sample was rotated for a predetermined period of time to cause the sample and the mating material to slide. The sliding conditions were as follows. Testing machine: Ring-ring friction and wear tester Rotation speed: 2m/sec Load applied to sample: 5Kg Sliding: None Rotation time: 3 hours Mating material: Hardened steel of Hv800-900 In this test, sliding was performed under the above conditions. The amount of wear on the mating material was investigated by measuring the surface roughness of the mating material. That is, as shown in Fig. 1, the surface roughness of the circular end face of the mating material 1 is measured in the radial direction, and the surface roughness of the portion 2 that slid against the sample and the surface roughness of the portion 3 that did not slide against the sample are determined. The value of the difference was taken as the amount of wear of the mating material 1. For example, as shown in Figure 2, if the height of the part 3 that does not slide on the sample and the part 2 that slides on the sample are the same, the amount of wear will be
It becomes 0μ. On the other hand, as shown in FIG. 3, if the height difference H between the portion 3 that does not slide on the sample and the portion 2 that slides on the sample is 0.4μ, the amount of wear will be 0.4μ. In addition, in this test, the amount of wear on the sample was investigated as follows. The plate thickness of the sample before and after the test was measured, and the difference was taken as the amount of wear. Table 2 shows the test results regarding the amount of wear. First, the amount of wear of the mating material 1 will be compared. This invention is a product of the present invention.
No.1, No.8, No.10, No.11, No.14, No.19,
When No. 23 was used, the wear amount of the mating material was 0 μ in all cases, and the mating material 1 did not wear out even though it was slid for as long as 3 hours. On the other hand, when Comparative Examples No. 24 to No. 27 were used, the mating material was worn by 0.05 to 0.4 μm. From the above, it can be seen that the sliding material of the present invention is very effective in preventing wear of the mating material. Next, compare the amount of wear on the samples themselves. No. 1, No. 3, No. 8, No. 10, No. 11, which are the products of the present invention,
In the case of No.14 and No.19, the amount of wear on the sample is 1.5 to 7μ
And small. On the other hand, comparative example No. 24~
In the case of No. 27, the amount of wear on the sample was 10 to 23μ, which was large. For example, the alumina content is 19% in both cases.
Compare No. 8 and No. 26. In the case of No. 8 containing 19% gamma-alumina, the amount of wear on the sample is
4μ, while containing 19% alpha alumina
In the case of No. 26, the amount of wear on the sample was 18 μ;
The amount of wear was 4.5 times greater than that of No. 8.
Similarly, No. 3 and No. 3 both have alumina content of 9%.
Comparing the amount of wear for sample No. 25, the amount of wear for No. 3 was 4μ. On the other hand, in the case of No. 25, the amount of wear is
It was 15μ, which was nearly 4 compared to No. 3. From the above, the present invention is extremely effective in preventing wear of the sliding material itself.

【table】

【table】

【table】

【table】

It can be seen that [Table]. Furthermore, in the case of No. 11 containing 0.5% molybdenum disulfide, No. 14 containing fluororesin or silicone oil
In the case of No. 19, the amount of wear on the sample is small.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the mating material used in the test example, Figure 2 is a diagram showing the surface roughness of the mating material when the wear amount of the mating material is 0μ, and Figure 3 is a diagram showing the surface roughness of the mating material when the wear amount of the mating material is 0.4 It is a figure which shows the surface roughness of the mating material in case μ. In the figure, 1 is the mating material, 2 is the part where the sample was slid,
3 indicates a portion where the sample was not slid.

Claims (1)

[Scope of Claims] 1. A sliding material whose main components are carbon graphite, alumina powder, and a synthetic resin binder, characterized in that the alumina powder is alumina mainly composed of gamma alumina. material. 2 A patent in which the proportion of carbon graphite is 40 to 70% by weight, the proportion of alumina powder is 2 to 30%, and the proportion of synthetic resin binder is 20 to 50%, taking the whole as 100%. A sliding material according to claim 1. 3. The sliding material according to claim 1, wherein the proportion of alumina powder is 5 to 20%. 4. The sliding material according to claim 1, wherein the alumina powder has a particle size of 0.5 to 200μ. 5 The synthetic resin binder is a thermosetting resin such as phenolic resin, epoxy resin, melamine resin, urea resin, polyimide resin, polyimide amide resin, modified phenolic resin, etc. Claim 1
Sliding materials described in Section 1. 6. The sliding material according to claim 1, wherein the proportion of the synthetic resin binder is 25 to 35%. 7. The sliding material according to claim 1, wherein the carbon graphite has a particle size of 0.5 to 200μ.