Composite solid lubricating material, inlaid sliding bearing and mining machinery thrust wheel shaft assembly

Abstract

The invention discloses a composite solid lubricating material, an embedded sliding bearing and a supporting wheel shaft assembly of mining machinery. The material comprises the following components in percentage by mass: 12%-18% of metallic tin powder, 14%-20% of metallic copper powder, 8%-14% of graphite powder, 4%-6% of molybdenum disulfide powder, 12%-18% of polytetrafluoroethylene powder, 18%-22% of paraffin powder, 4%-6% of barium sulfate powder, 4%-6% of molybdenum oxide powder and 8%-10% of ethyl acetate. The problems that existing grease lubrication is fast in failure, frequent in maintenance, short in service life and not suitable for unmanned operation are solved. Under the combined action of two lubricants, namely the lubricating grease and the composite solid lubricating material, the period of filling the lubricants is prolonged to 15 days and more than 15 days from one time of filling every day when the lubricating grease is independently used, so that the wear resistance of the sliding bearing is greatly improved, and the aim of long lubricating period is fulfilled.

Description

TECHNICAL FIELD

[0001] The present application relates to a lubricating material, in particular to a composite solid lubricating material, an inlaid sliding bearing and a mine machinery supporting wheel shaft assembly. BACKGROUND

[0002] In the mining operation, the electric excavator as the key production equipment, its operation efficiency directly affects the overall production of the mine. The traditional electric excavator each support and rotating part generally uses tin bronze sliding bearing, which needs to be injected with dry oil lubrication once a day to maintain normal operation. However, the existing sliding bearing has the outstanding problems of large lubrication maintenance workload and long maintenance time, especially the frequent bearing failure in the key parts such as the supporting wheel shaft assembly with the largest load, which has a significant impact on the continuous production of the mine.

[0003] With the rapid development of smart mine technology, especially the popularization and application of "5G + remote control" mode, the physical separation of post personnel and equipment is gradually realized in the mine equipment. The unmanned degree of the working area of the electric excavator is gradually improved, and the maintenance personnel will enter the mining site once every fifteen days to maintain the equipment. This change makes the traditional sliding bearing lubrication system relying on manual work face severe challenges: the reduction of lubrication frequency leads to insufficient lubrication of the bearing, which aggravates the wear failure rate and further restricts the improvement of the mine production capacity. Under this background, how to improve the performance of the sliding bearing material and the lubrication method, significantly prolong the service life of the supporting wheel shaft assembly and the sliding bearing, reduce the maintenance frequency and shorten the replacement cycle has become the core technical problem to be solved for realizing the remote and efficient operation of the smart mine. The breakthrough of this problem has universal significance for promoting the intelligent upgrading of various mines and ensuring the reliable operation of the equipment in the unmanned operation scene.

[0004] The existing document 1 (Chinese utility model patent application with publication number CN206513717U) discloses an oil lubricated sliding bearing, which reduces wear by forming an oil film in the shaft hole, but has obvious deficiencies in actual application: when the bearing axis is not in a horizontal position or is in a high temperature environment, the lubricating oil will quickly flow away due to the action of gravity or centrifugal force, resulting in lubrication failure and increasing the maintenance workload. In addition, the traditional oil lubrication method is difficult to achieve automatic oil replenishment in the unmanned mine scene, and cannot meet the demand of a fifteen-day maintenance cycle. Document 2 (Chinese invention patent application with authorization number CN111575699B) discloses a self-lubricating aluminum-based composite material and a preparation method thereof, which attempts to improve wear resistance by adding a solid lubricant, but its main drawback is that the lubricating layer is a high polymer material with short service life, and the solid lubricant has large defects and poor bonding force at the bonding interface with the matrix, making it difficult to form a complete lubricating film during friction and wear, especially under heavy load and impact working conditions. In addition, the solid lubricant in the traditional metal-based solid self-lubricating composite material is prone to segregation, resulting in increased porosity, decreased density, and decreased mechanical properties of the material, as well as increased wear, which seriously affects the service life. SUMMARY

[0005] The purpose of the present application is to provide a composite solid lubricating material, an inlaid sliding bearing and a mine mechanical load wheel shaft assembly, which solves the problems of fast lubricating grease failure, frequent maintenance and short service life of the existing grease lubrication, and is not suitable for unmanned operation. Under the joint action of lubricating grease and composite solid lubricating material, the anti-wear performance of the sliding bearing can be greatly improved, and the service life is prolonged. The period of adding lubricant can be improved from once a day when using general lubricating grease alone to once every fifteen days or more.

[0006] To achieve the above purpose, the present application provides a composite solid lubricating material, which comprises the following components by mass fraction: 12% to 18% of metal tin powder, 14% to 20% of metal copper powder, 8% to 14% of graphite powder, 4% to 6% of molybdenum disulfide powder, 12% to 18% of polytetrafluoroethylene powder, 18% to 22% of paraffin powder, 4% to 6% of barium sulfate powder, 4% to 6% of molybdenum oxide powder, and 8% to 10% of ethyl acetate.

[0007] Preferably, the mass fraction of the metal copper powder is 14% to 18%; and the mass fraction of the graphite powder is 10% to 12%.

[0008] Preferably, the mass fraction of the ethyl acetate is 10% to 12%; the mass fraction of the barium sulfate powder is 4% to 5%; the mass fraction of the paraffin powder is 18% to 20%; and the mass fraction of the polytetrafluoroethylene powder is 12% to 16%.

[0009] Preferably, the mass fraction of the tin metal powder is 12%; the mass fraction of the copper metal powder is 18%; the mass fraction of the graphite powder is 12%; the mass fraction of the molybdenum disulfide powder is 4%; the mass fraction of the ethyl acetate is 10%; the mass fraction of the barium sulfate powder is 4%; the mass fraction of the paraffin powder is 20%; and the mass fraction of the polytetrafluoroethylene powder is 16%.

[0010] Preferably, the mass fraction of the tin metal powder is 18%; the mass fraction of the copper metal powder is 14%; the mass fraction of the graphite powder is 10%; the mass fraction of the molybdenum disulfide powder is 6%; the mass fraction of the ethyl acetate is 10%; the mass fraction of the barium sulfate powder is 5%; the mass fraction of the paraffin powder is 10%; and the mass fraction of the polytetrafluoroethylene powder is 12%.

[0011] The application provides a preparation method of the composite solid lubricating material. (1) mixing and stirring tin metal powder, copper metal powder, graphite powder, colloidal molybdenum disulfide powder, polytetrafluoroethylene powder, paraffin powder, barium sulfate powder, molybdenum oxide powder and ethyl acetate to obtain a mixed powder; (2) pressing the mixed powder to obtain a block material; (3) solidifying the block material; (4) cooling the solidified block material to room temperature in air to obtain the composite solid lubricating material.

[0012] Preferably, in step (1), the stirring speed is 45 rpm and the stirring time is 2 h; or / and, in step (2), the pressing pressure is 65 MPa; or / and, in step (3), the solidifying temperature is 150-180 ℃ and the solidifying time is 2-6 h.

[0013] The application provides an embedded sliding bearing containing the composite solid lubricating material.

[0014] Preferably, the composite solid lubricating material is in a cylindrical shape, and the outer diameter of the composite solid lubricating material is the same as the diameter of the embedded hole.

[0015] The application provides a supporting wheel assembly containing the embedded sliding bearing.

[0016] This invention provides the application of the composite solid lubricating material as described above, or the embedded sliding bearing containing the composite solid lubricating material as described above, or the support roller assembly containing the embedded sliding bearing as described above in mining machinery.

[0017] The composite solid lubricating material, embedded sliding bearing, and mining machinery support roller axle assembly of the present invention solve the problems of rapid failure, frequent maintenance, short lifespan, and unsuitability for unmanned operation of existing grease lubrication systems, and have the following advantages: 1. Compared with the prior art, the present invention, with the combined action of two lubricants, grease and composite solid lubricant, increases the lubrication cycle from once a day when using grease alone to once every fifteen days or more. This greatly improves the wear resistance of sliding bearings, extends their service life, and perfectly matches the 15-day maintenance cycle of unmanned mines, achieving the goal of a long lubrication cycle.

[0018] 2. Regarding the bearing structure, the sliding bearing of this invention employs a periodically arranged array of embedded holes, into which a composite solid lubricant material is embedded (the hole diameter is 3%~8% of the inner diameter of the sliding bearing, and the total area of ​​the embedded holes accounts for 20%~30%), constructing a binary synergistic system of "solid lubrication-grease lubrication". Mining operation tests show that after 150 days of testing, the radial cumulative wear of the embedded sliding bearing containing the aforementioned composite solid lubricant material is only 28% of that of a commonly used copper alloy CuSn10 sliding bushing, achieving the goal of a long lubrication cycle.

[0019] 3. The composite solid lubricating material and support structure of the present invention can be applied to scenarios where personnel and equipment are physically separated in smart mines. It can solve the contradiction between the cycle of mine equipment maintenance personnel entering the equipment area and the cycle of lubricating oil filling. It has universal significance and potential economic value for promoting the intelligent upgrading of various mining machinery and ensuring the reliable operation of equipment in unmanned operation scenarios. Attached Figure Description

[0020] Figure 1 This is an optical photograph of the microstructure of the composite solid lubricant material of the present invention.

[0021] Figure 2 This is a schematic diagram of the sliding bearing structure of the present invention.

[0022] Figure 3 This is a schematic diagram of the support roller assembly structure of the present invention.

[0023] Figure 4 This is a schematic diagram of the support shaft structure of the present invention.

[0024] Figure 5 This is a schematic diagram of the assembly of the sliding bearing, support roller, support shaft, graphite packing seal, and sealing end cap of the present invention.

[0025] Note: 10, supporting wheel; 20, embedded sliding bearing; 201, sliding bearing copper alloy base; 202, embedded hole; 203, sealing ring; 211, oil inlet hole; 212, inner oil groove; 213, outer oil groove; 31, graphite packing seal; 41, sealing end cover; 50, supporting shaft; 501, grease injection hole; 502, sealing end cover groove; 503, supporting shaft assembly anti-rotation structure; 61, bolt; 62, nut. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0027] The materials involved in the following embodiments are as follows: Metal tin powder (Sn) particle size is -300 mesh, purity is 99.9%.

[0028] Metal copper powder (Cu) particle size is -250 mesh, purity is 99.5%.

[0029] Graphite powder (C) particle size is 5 μm~25 μm, purity is 99.0%.

[0030] Colloidal molybdenum disulfide powder (MoS2) and polytetrafluoroethylene powder (PTFE) particle size is 1 μm~10 μm, purity is 99.5%.

[0031] Paraffin wax powder (PW) particle size is -200 mesh, melting point is 55℃~60℃.

[0032] Barium sulfate powder (BaSO4) particle size is 10 μm~30 μm, purity is 98%.

[0033] Molybdenum oxide powder (MoO3) particle size is -400 mesh, purity is 99%.

[0034] Ethyl acetate adhesive density is 0.90g / cm 3 , pH value is 6.5.

[0035] Embodiment 1 A composite solid lubricating material, as shown in Figure 1 The microstructure optical photo of the composite solid lubricating material of the present application is shown in the figure, which contains the following components in percentage: Metal tin powder (Sn) 12%, metal copper powder (Cu) 18%, graphite powder (C) 12%, colloidal molybdenum disulfide powder (MoS2) 4%, polytetrafluoroethylene powder (PTFE) 16%, paraffin wax powder (PW) 20%, barium sulfate powder (BaSO4) 4%, molybdenum oxide powder (MoO3) 4%, and ethyl acetate adhesive (EA) 10%.

[0036] The preparation method of the composite solid lubricating material comprises: (1) After the metal tin powder, the metal copper powder, the graphite powder, the colloidal molybdenum disulfide powder, the polytetrafluoroethylene powder, the paraffin wax powder, the barium sulfate powder, the molybdenum oxide powder, and the ethyl acetate adhesive are mixed in the above proportions, the mixed powders are mixed in a kneader to obtain a uniformly mixed powder, the rotation speed of the driving shaft of the kneader is 45 rpm, and the kneading time is 2 h. (2) The mixed powders are pressed and formed in a steel mold to obtain a block material (cylindrical with a bottom surface diameter of 10 mm), and the pressing pressure is 65 MPa.

[0037] (3) The block material is subjected to curing treatment in an oven, the curing temperature is 150°C, the curing time is 6 h, and the curing atmosphere is air, i.e., the atmosphere.

[0038] (4) The cured block material is cooled to room temperature in air to obtain the composite solid lubricating material.

[0039] A support wheel assembly, as shown in Figure 3 The support wheel assembly structural diagram of the present application, the assembly includes support wheel 10, inlay type sliding bearing 20, graphite packing seal strip 31, sealing end cover 41, support shaft 50, bolt 61 and nut 62.

[0040] The inlay type sliding bearing 20 is a cylinder, as shown in Figure 2As shown, it includes sliding bearing copper alloy base 201, inlay hole 202, sealing ring 203, oil inlet hole 211, inner oil groove 212 and outer oil groove 213. The sliding bearing copper alloy base 201 serves as the main body and framework of the bearing, bearing the radial load and impact force from the shaft, ensuring mechanical strength; it can quickly conduct the heat generated by friction out of the bearing to prevent overheating. The inlay hole 202 is uniformly embedded in the friction surface of the sliding bearing copper alloy base 201, and its size is adapted to the size of the composite solid lubricating material, used to install the composite solid lubricating material. When the bearing is running, the composite solid lubricating material forms a lubricating film on the contact surface of the shaft and the bearing through friction, realizing the core self-lubricating function. The sealing ring 203 is installed in the sealing groove on the end face of the sliding bearing copper alloy base 201, and forms an interference fit with the bearing seat or shaft neck, preventing the leakage of lubricating grease inside the bearing to the outside, maintaining the lubricating effect; blocking the entry of external pollutants such as dust, sand and moisture into the bearing interior, protecting the friction pair and greatly extending the bearing life. The inner oil groove 212 is four recesses symmetrically arranged on the inner wall of the sliding bearing copper alloy base 201 in the form of an axial circular arc, with a circular arc radius of 5 mm and an oil groove depth of 3 mm. The oil inlet hole 211 is centrally provided in the inner oil groove 212, connecting the channel of the external and internal lubricating systems. The outer oil groove 213 is an annular groove provided on the outer cylindrical surface of the sliding bearing copper alloy base 201 and is in communication with the oil inlet hole 211. The injected lubricating grease is distributed to the outer oil groove 213 and the inner oil groove 212 through the oil inlet hole 211. The sealing ring 203 is an O-shaped sealing ring, and its material is butyronitrile rubber. The inlay sliding bearing is made of copper alloy with a grade of CuAl9Mn2. The inlay sliding bearing 20 has an inner diameter of 200 mm, the inlay hole 202 has a diameter of 10 mm, and the total area of the inlay hole 202 accounts for 21% of the outer surface area of the inlay sliding bearing 20. The active lubrication path (grease system) is: oil gun → oil inlet hole 211 → outer oil groove 213 → inner oil groove 212 → covering the entire bearing inner hole friction surface. When the grease is gradually consumed or cannot be replenished in time, the composite solid lubricating material embedded in the inlay hole 202 begins to work, ensuring that the bearing will not be immediately damaged due to lack of oil, which is the core design to realize long lubrication period and high reliability.

[0041] The load bearing shaft 50 includes a grease injection hole 501, a sealing end cover groove 502 and a load bearing shaft assembly anti-rotation structure 503, as shown in Figure 4As shown in the schematic view of the support axle structure, the grease injection hole 501 (lubrication hole) is located at the center of the right end of the support axle 50 and is a radial through hole that penetrates the outer circular surface of the axle to the T-shaped hole in the center, i.e., the inner hole of the axle, which is the passage for the grease and the inlet for the external lubricating grease. The grease is injected through the grease injection hole 501 by aiming the oil gun at the grease injection hole 501, and the grease enters the longitudinal passage in the center of the axle through the grease injection hole 501 and is finally delivered to the bearing friction surface that needs to be lubricated. This is the key maintenance point for ensuring that the support wheel can operate flexibly for a long time. The sealing end cover groove 502 is symmetrically arranged on the annular groove on the outer side wall of the right end of the support axle 50, is located around the 501 grease injection hole, and is not connected to the 501 grease injection hole, is used for installing the sealing end cover 41, forms a strict sealing line, prevents the lubricating grease from leaking from the axle end, blocks the invasion of external pollutants such as mud and water into the bearing, and prolongs the service life of the bearing. The sealing end cover 41 is a combined sealing ring, which is composed of an inner layer of nitrile rubber O-shaped sealing ring and an outer layer of polytetrafluoroethylene lining. The support axle assembly anti-rotation structure 503 is located in the uncut part of the left end of the axle and is a radial through hole or a flat notch processed on the surface of the axle. During assembly, the axle is fixed on the machine frame by passing the hole with a positioning pin or a bolt to prevent the axle from moving axially during operation.

[0042] Comparative Example 1 A support wheel assembly is basically the same as that of Example 1, except that the sliding bearing is not provided with the inlaid hole 202, and the composite solid lubricating material is not added during the test experiment.

[0043] Example 2 A composite solid lubricating material contains the following components in percentage by mass: Metal tin powder (Sn) accounts for 18%, metal copper powder (Cu) accounts for 14%, graphite powder (C) accounts for 10%, molybdenum disulfide powder (MoS2) accounts for 6%, polytetrafluoroethylene powder (PTFE) accounts for 12%, paraffin powder (PW) accounts for 20%, barium sulfate powder (BaSO4) accounts for 5%, molybdenum oxide powder (MoO3) accounts for 5%, and ethyl acetate (EA) accounts for 10%.

[0044] The preparation method of the above-mentioned composite solid lubricating material is basically the same as that of Example 1, except that: In step (3), the curing temperature is 180°C, and the curing time is 2h. After the same operation as in Example 1, the composite solid lubricating material is obtained.

[0045] A support wheel assembly is basically the same as that of Example 1, except that: The inner diameter of the inlaid sliding bearing is 200 mm, the diameter of the inlaid hole 202 provided on the sliding bearing is 10 mm, and the total area of the inlaid hole 202 accounts for 28% of the area of the 20 inlaid surface of the inlaid sliding bearing.

[0046] The inner oil groove 212 is in the shape of a circular arc with a radius of 5 mm and a depth of 3 mm.

[0047] Experimental Example 1 verifies the lubricating effect of the composite solid lubricating material The composite solid lubricating material of Example 1, which is in the shape of a cylinder with a bottom surface diameter of 10 mm, is embedded in the embedding hole 202 of the embedding sliding bearing of Example 1 to form a sliding bearing containing the composite solid lubricating material together with the sealing ring 203.

[0048] On a mining machine, the sliding bearing containing the composite solid lubricating material of Example 2, the sliding bearing containing the composite solid lubricating material of Example 1, the sliding bearing of Comparative Example 1, and a commercially available copper alloy CuSn10 sliding bushing (CuSn10 comparative test piece) are respectively sleeved on the load bearing axle of the present application as shown in Figure 4 The graphite packing seal strip 31 and the sealing end cover 41 are used for sealing. Then, the load bearing wheel of the present application is assembled as shown in Figure 3 The bolt 61 and the nut 62 are used for fixing. Five load bearing wheels are arranged on each side of each electric forklift truck. The sliding bearing of Example 1 and the CuSn10 comparative test piece are arranged on the same electric forklift truck in corresponding positions on the left and right sides to ensure that the performance is measured under the same conditions. The radial wear and the use effect are shown in Table 1.

[0049] Table 1: Test results of performance comparison experiment

[0050] As shown in Table 1, after 150 days of experiment, the radial cumulative wear of the sliding bearing of the present application embedded with the composite solid lubricating material is only 28% of that of the commonly used copper alloy CuSn10 sliding bushing, achieving the goal of long lubrication period. Therefore, the anti-wear performance of the embedding sliding bearing of the present application of Example 1 containing the composite solid lubricating material and made of copper alloy with the grade of CuAl9Mn2 is obviously better than that of the commonly used copper alloy bushing.

[0051] In addition, the sliding bearing of Example 2 or the sliding bearing of Comparative Example 1 and the CuSn10 comparative test piece are arranged on the same electric forklift truck in corresponding positions on the left and right sides to ensure that the performance is measured under the same conditions. The test results show that the anti-wear performance of the embedding sliding bearing of the present application of Example 2 containing the composite solid lubricating material and made of copper alloy with the grade of CuAl9Mn2 is the same as that of Example 1 of the present application. However, the anti-wear performance of the sliding bearing of Comparative Example 1 is close to that of the CuSn10 comparative test piece.

[0052] While the application has been described in detail and with reference to specific preferred embodiments thereof, it will be apparent to one skilled in the art that various modifications and alternatives can be employed without departing from the spirit and scope of the application. Accordingly, the scope of the application should be determined by the appended claims and their equivalents.

Claims

1. A composite solid lubricating material, characterized by, The material comprises the following components by mass fraction: 12%~18% of metal tin powder, 14%~20% of metal copper powder, 8%~14% of graphite powder, 4%~6% of molybdenum disulfide powder, 12%~18% of polytetrafluoroethylene powder, 18%~22% of paraffin powder, 4%~6% of barium sulfate powder, 4%~6% of molybdenum oxide powder, and 8%~10% of ethyl acetate.

2. The composite solid lubricating material according to claim 1, wherein The mass fraction of the metal copper powder is 14%~18%; the mass fraction of the graphite powder is 10%~12%.

3. The composite solid lubrication material according to claim 2, characterized in that The mass fraction of the ethyl acetate is 10%~12%; the mass fraction of the barium sulfate powder is 4%~5%; the mass fraction of the paraffin powder is 18%~20%; and the mass fraction of the polytetrafluoroethylene powder is 12%~16%.

4. A method for producing the composite solid lubricating material according to any one of claims 1 to 3, characterized by, The method comprises: (1) mixing and stirring metal tin powder, metal copper powder, graphite powder, colloidal molybdenum disulfide powder, polytetrafluoroethylene powder, paraffin powder, barium sulfate powder, molybdenum oxide powder, and ethyl acetate to obtain a mixed powder; (2) pressing the mixed powder to form a block material; (3) solidifying the block material; (4) cooling the solidified block material to room temperature in air to obtain a composite solid lubricating material.

5. The production method according to claim 4, characterized by, In step (1), the stirring time is 2h; in step (2), the pressing pressure is 65 MPa; and in step (3), the solidification temperature is 150℃~180℃, and the time is 2h~6h.

6. An inlaid plain bearing comprising the composite solid lubricating material according to any one of claims 1 to 3, characterized in that The inlaid hole of the inlaid sliding bearing is embedded with the composite solid lubricating material according to any one of claims 1~3; the diameter of the inlaid hole is 3%~8% of the inner diameter of the inlaid sliding bearing, and the total area of the inlaid holes of the bearing is 20%~30% of the area of the inlaid surface of the inlaid sliding bearing.

7. A load wheel assembly comprising the inlaid sliding bearing according to claim 6.

8. Use of the composite solid lubricating material according to any one of claims 1~3, or the inlaid sliding bearing according to claim 6, or the load wheel assembly according to claim 7, in a mine machinery.

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