JPS6029012B2 - ceramic sliding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ceramic sliding device suitable for forming rotating and sliding parts such as bearings and seals of mechanical devices.

In the rotating and moving parts of mechanical devices, sliding devices are constructed of various materials that have low frictional resistance and do not impair mechanical efficiency as much as possible.For example, metal bearings using ball bearings, flat bearings, etc. Bearings made of resin made of ethylene, 4-keyed ethylene, etc., and bearings made of other carbon materials are available for practical use.

In such bearings, it is necessary to use lubricant (oil) on these sliding parts, except in cases where the bearings are used in a special manner or when resin, carbon material, etc. are used. However, it is impossible to use lubricating oil under special conditions such as when rotating or sliding parts of mechanical equipment are under high temperature conditions, submerged in liquid, or in a corrosive atmosphere. There are many cases where the use of lubricating oil is not functionally desirable.

Therefore, materials such as carbon and boron nitride have been used for rotating and sliding members used under high temperature conditions.

These are most commonly used as rotating tank moving parts under high-temperature conditions because they have low frictional resistance and good swamp dynamic characteristics, but they are subject to extremely high wear due to swamp movement and have a short lifespan as sliding members, so they must be replaced. Not only did maintenance require a large amount of money and time, but the mechanical strength of the material itself was low.
It is unsuitable for use as a sliding member in a device that is subject to a large load, and is the cause of lowering the reliability of the device as a whole.

The present invention was developed in view of the drawbacks of existing sliding devices as described above, and as a result of tests using various materials, it was found that the sliding members constituting the fixed part and the sliding part were It has been found that the best is a sliding device in which one of the two is a non-consolidation body mainly composed of silicon nitride, and the other is a sintered silk body mainly composed of silicon carbide.

That is, carbon (sample number No.
1) Disc-shaped test pieces of sintered bodies of silicon carbide (sample number No. 2), alumina (sample number No. 3), and silicon nitride (sample number No. 4) with a thickness of 8 yen and a diameter of 3 dia. and,
The coefficient of friction is relatively small, the mechanical strength is greater than that of carbon, and the amount of wear is small. 10,0 at a circumferential speed of 122.5 skin/sec under a contact condition with a contact load of 10k9 with lubrication (no lubrication).
FIG. 1 shows the relationship between the friction coefficient A and the amount of wear of each material when rotated at 000 rotations. As is clear from the correlation shown in FIG. 1, sample number M. In friction with carbon No. 1, the friction coefficient is small, but the amount of wear is extremely large.

Another sample snake. Good measurement results were obtained for silicon nitride No. 4, showing that both the friction coefficient and the amount of wear were extremely small. Furthermore, as shown in Table 1, the wear amount of each sample was measured after 10,000 rotations with a contact load of 10 k9 for one silicon carbide as the opposing bog member. The sample with the least amount of wear in this case is sample M.
．． 4, but it was also found that the amount of wear when lubricated was relatively large compared to other samples.

[Contact load = 10 &] Based on these measurement results, there are two major requirements for sliding members used under harsh conditions, especially without lubrication, such as at high temperatures, in powder, and in corrosive gas atmospheres. The other side is silicon carbide, which is an excellent sliding member because it meets the requirements of 'i) low friction coefficient, [ii] low wear amount, and has low heat generation and thermal expansion coefficient due to vibration. It has been found that a silicon nitride heating element is most suitable for the sliding member.

Therefore, in particular, as a member constituting an oil-free dry sliding part, it is possible to use a material composed of a sintered body mainly composed of silicon carbide and a sintered body mainly composed of silicon nitride. The sliding parts have less friction and wear, and are durable, making it possible to greatly improve the reliability of the entire mechanical device.

Next, examples of the application of the sliding member according to the present invention to mechanical devices include the use of lubricating oil in rotary working parts or shaft sealing parts of heat engines, such as internal combustion engines, or bearing devices in high-temperature furnaces. Sliding devices that operate under impossible high temperature conditions, rotating sliding parts in corrosive liquids or gases, abrasive fluids such as powder transport bags, and flywheel bearings in slurry liquid tanks. It can be applied to a wide range of equipment, such as rotary slide devices that operate inside the machine and mechanical seals for other pumps.

Among these, an example in which the sliding device of the present invention is applied to a screw conveyor bearing in a powder transport device will be specifically described in detail with reference to the drawings. This casing 1 has retainers 2 and 2' attached thereto, and the rotary bearing portion is held by the two retainers 2 and 2'. In this rotary bearing mechanism, in order to rotatably support a metal shaft 3 as a rotary shaft, the shaft 3 is equipped with a sliding plate formed into a cylindrical shape from a sintered body whose main component is silicon carbide (hereinafter referred to as SIC). A moving member 4 is adjacently attached, and the sliding member 4 is locked to the shaft 3 by a metal pin 5 for preventing rotation so that the moving member 4 rotates together with the shaft 3.

Further, 6 is a sliding member on the fixed side that slides in direct contact with the outer peripheral surface of the super-moving member 4 that is integrally attached to the shaft 3. This is a Si3M4 sliding member made of a sintered body mainly composed of silicon nitride (hereinafter referred to as TSi3M4), which is a material with excellent sliding characteristics such as low frictional resistance and wear resistance. In this case, the Si3M4 sliding member 6 is iron-coupled so as to rotatably support the SiC sliding member 4 attached to the shaft 3, but the shape of the Si3N4 sliding member 6 may be cylindrical. , a cylindrical shape divided into two in the vertical direction is attached with a spacer 7 interposed therebetween, and the retainer 2, 2' is sandwiched and screwed to the retainer. Note that 8 in Fig. 1 is a stop ring, which is used to fix the SIC sliding member 4 attached to the shaft 3 in a predetermined position and to prevent the metal pin 5 from coming off, but it is not particularly necessary. isn't it. Therefore, in the rotation mechanism configured as described above, when the shaft 3 rotates, the outer peripheral surface of the cylindrical SiC sliding member 4 attached to the shaft 3 is rotated by the Sj3M4 held by the retainers 2, 2'. The shaft 3 rotates by sliding against the inner circumferential surface of the sliding member 6.
As mentioned above, the sliding machine side made of a pair of 3M4 silk has good sliding properties as a bearing, so it can constitute an excellent sliding machine side. By the way, in the embodiment of the present invention, an example was given in which the Si3M sliding member 4 was used on the rotating side and the Si3M sliding member 4 was used on the fixed support side, but the invention is not limited to this. Sic on fixed side
A sliding member may be used, and in short, a sliding device may be constructed by vertically aligning sliding members each made of Sic-Si3M.

In addition, although the tank motion device of the present invention has sufficient sliding characteristics to operate under conditions where it is impossible to supply lubricant, under conditions where it is possible to supply lubricant, it is necessary to supply lubricating oil. Needless to say, it can be used as a general sliding device.

As described above, according to the sliding device of the present invention, the coefficient of friction is 4.0 and the amount of wear is extremely small, so that the life of the sliding device is extended and the need for replacement and maintenance is greatly reduced.

In addition, the reliability of the sliding parts is high as there is no seizure development on the sliding parts even when there is no lubrication, so the reliability and durability of the entire device using this can be improved. It has a good effect.

[Brief explanation of the drawing]

FIG. 1 is a graph plotting the relationship between the coefficient of friction and the amount of wear between silicon carbide as a sliding part and other loosely combined compacts based on measurement results. FIG. 2 is a sectional view of a screw conveyor bearing as an application example of the sliding device of the present invention. Figure 3 is A-A in Figure 2.
A line cross-sectional view is shown. 3...Shaft, 4
, 6...Sliding member, 7...Subesa. 8...stop ring. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 One of the rotating and fixed members, which are sliding members of the rotating and fixed parts of a mechanical device, is a sintered body whose main component is silicon nitride, and the other is a sintered body whose main component is silicon carbide. A ceramic sliding device characterized by comprising each of the above.