Composite solid lubricant material, inlaid plain bearing and mine machinery wheel axle assembly

Abstract

The application discloses a kind of composite solid lubricating material, mosaic sliding bearing and mine machinery supporting wheel axle assembly, the material includes the following mass fraction of components: 12%~18% metal tin powder, 14%~20% metal copper powder, 8%~14% graphite powder, 4%~6% molybdenum disulfide powder, 12%~18% polytetrafluoroethylene powder, 18%~22% paraffin powder, 4%~6% barium sulfate powder, 4%~6% molybdenum oxide powder, 8%~10% ethyl acetate.The application solves the problem that existing grease lubrication fails fast, is maintained frequently, has short service life and is not suitable for unmanned operation.Under the joint action of lubricating grease and composite solid lubricating material, the period of adding lubricant is increased to fifteen days and above once every fifteen days from once a day when using lubricating grease alone, which greatly improves the wear resistance of sliding bearing and achieves the goal of long lubrication period.

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 metal tin powder is 12%; the mass fraction of the metal copper 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 metal tin powder is 18%; the mass fraction of the metal copper 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 present application provides a preparation method of the composite solid lubricating material as described, which comprises:

[0012] (1) mixing and stirring the metal tin powder, the metal copper powder, the graphite powder, the colloidal molybdenum disulfide powder, the polytetrafluoroethylene powder, the paraffin powder, the barium sulfate powder, the molybdenum oxide powder and the ethyl acetate to obtain a mixed powder;

[0013] (2) pressing the mixed powder to form a block material;

[0014] (3) solidifying the block material;

[0015] (4) cooling the solidified block material to room temperature in air to obtain the composite solid lubricating material.

[0016] 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 solidification temperature is 150-180℃ and the solidification time is 2-6 h.

[0017] The present application provides an embedded sliding bearing containing the composite solid lubricating material as described, wherein the embedded sliding bearing is embedded with the composite solid lubricating material as described in the embedded hole; the diameter of the embedded hole is 3-8% of the inner diameter of the embedded sliding bearing, and the total area of the embedded holes of the embedded sliding bearing is 20-30% of the embedded surface area of the embedded sliding bearing; the material of the embedded sliding bearing is CuAl9Mn2.

[0018] Preferably, the composite solid lubricating material is in a cylindrical shape, and the outer diameter of the cylindrical shape is the same as the diameter of the embedded hole.

[0019] The present application provides a load wheel assembly containing the embedded sliding bearing.

[0020] The application provides a composite solid lubricating material, an inlaid sliding bearing containing the composite solid lubricating material, and an application of a load wheel assembly containing the inlaid sliding bearing in a mine machinery.

[0021] The composite solid lubricating material, the inlaid sliding bearing and the mine machinery load wheel shaft assembly solve the problems of quick failure of existing grease lubrication, frequent maintenance, short service life and inadaptation to unmanned operation, and have the following advantages.

[0022] 1. Compared with the prior art, under the joint action of the lubricating grease and the composite solid lubricating material, the period of adding lubricant is increased from once a day to once in 15 days or more when the lubricating grease is used alone, the wear resistance of the sliding bearing is greatly improved, the service life is prolonged, the 15-day maintenance cycle of the unmanned mine is completely matched, and the long lubrication cycle goal is achieved.

[0023] 2. In the bearing structure, the sliding bearing adopts periodic arrangement of inlaid holes, the composite solid lubricating material is embedded in the inlaid holes (the hole diameter is 3% to 8% of the inner diameter of the sliding bearing, and the total area of the inlaid holes accounts for 20% to 30%), and a binary collaborative system of “solid lubrication-grease lubrication” is constructed. The mine working condition experiment shows that after 150 days of experiment, the radial cumulative wear amount of the inlaid sliding bearing containing the composite solid lubricating material is only 28% of that of the commonly used copper alloy CuSn10 sliding bushing, and the long lubrication cycle goal is achieved.

[0024] 3. The composite solid lubricating material and the load structure of the application can be applied to the scene where the intelligent mine post personnel and the equipment are physically separated, can solve the contradiction that the period of the maintenance personnel entering the equipment area does not match the lubricating oil filling period, and has universal significance and potential economic value for promoting the intelligent upgrading of various mine machinery and ensuring the reliable operation of the equipment in the unmanned operation scene. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a microstructure optical photo of the composite solid lubricating material of the application.

[0026] Figure 2 It is a sliding bearing structure schematic diagram of the application.

[0027] Figure 3 It is a load wheel assembly structure schematic diagram of the application.

[0028] Figure 4 It is a load wheel shaft structure schematic diagram of the application.

[0029] Figure 5This 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.

[0030] Notes: 10. Track roller; 20. Embedded sliding bearing; 201. Sliding bearing copper alloy base; 202. Embedding hole; 203. Sealing ring; 211. Oil inlet; 212. Inner oil groove; 213. Outer oil groove; 31. Graphite packing seal strip; 41. Sealing end cap; 50. Track shaft; 501. Grease injection hole; 502. Sealing end cap groove; 503. Anti-rotation structure for track shaft assembly; 61. Bolt; 62. Nut. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The materials involved in the following embodiments are as follows:

[0033] The tin powder (Sn) has a particle size of -300 mesh and a purity of 99.9%.

[0034] The copper powder (Cu) has a particle size of -250 mesh and a purity of 99.5%.

[0035] The graphite powder (C) has a particle size of 5 μm to 25 μm and a purity of 99.0%.

[0036] Colloidal molybdenum disulfide powder (MoS2) and polytetrafluoroethylene powder (PTFE) have a particle size of 1 μm to 10 μm and a purity of 99.5%.

[0037] The particle size of the paraffin powder (PW) is -200 mesh, and the melting point is 55℃~60℃.

[0038] The barium sulfate powder (BaSO4) has a particle size of 10 μm to 30 μm and a purity of 98%.

[0039] The molybdenum oxide powder (MoO3) has a particle size of -400 mesh and a purity of 99%.

[0040] The density of ethyl acetate adhesive is 0.90 g / cm³. 3 pH value 6.5.

[0041] Example 1

[0042] A composite solid lubricant, such as Figure 1 The image shown is an optical micrograph of the composite solid lubricant material of the present invention. Its mass percentage is expressed as the following components by mass fraction:

[0043] 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%.

[0044] The preparation method of the composite solid lubricating material comprises the following steps:

[0045] (1) 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, and then mixed into a uniformly mixed powder in a kneader, the driving shaft rotation speed of the kneader is 45 rpm, and the kneading time is 2 h;

[0046] (2) The mixed powder is pressed into a block material (cylindrical with a bottom diameter of 10 mm) in a steel mold, and the pressing pressure is 65 MPa.

[0047] (3) The block material is cured in an oven, the curing temperature is 150°C, the curing time is 6 h, and the curing atmosphere is air, i.e. atmosphere.

[0048] (4) The cured block material is cooled to room temperature in air to obtain the composite solid lubricating material.

[0049] A supporting wheel assembly, as shown in Figure 3 The supporting wheel assembly structure diagram of the present application, the assembly includes supporting wheel 10, inlay type sliding bearing 20, graphite packing seal strip 31, sealing end cover 41, supporting shaft 50, bolt 61 and nut 62.

[0050] 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 inner diameter of the inlay sliding bearing 20 is 200 mm, the diameter of the inlay hole 202 is 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.

[0051] 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 diagram 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 to ensure 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, located around the 501 grease injection hole, and not connected with the 501 grease injection hole, used for installing the sealing end cover 41 to form a strict sealing line to prevent the lubricating grease from leaking from the axle end and block the invasion of external pollutants such as mud and water into the bearing, prolonging the service life of the bearing. The sealing end cover 41 is a combined sealing ring 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 a positioning pin or bolt through the hole to prevent axial movement of the axle during operation.

[0052] Comparative Example 1

[0053] A support wheel assembly is basically the same as that of Example 1, except that the inlaid hole 202 is not provided in the sliding bearing, and the composite solid lubricating material is not added during the test experiment.

[0054] Example 2

[0055] A composite solid lubricating material contains the following components in percentage by mass:

[0056] 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%.

[0057] The preparation method of the above-mentioned composite solid lubricating material is basically the same as that of Example 1, except that:

[0058] In step (3), the curing temperature is 180°C, and the curing time is 2h. After the same operation as in Example 1, a composite solid lubricating material is obtained.

[0059] A support wheel assembly is basically the same as that of Example 1, except that:

[0060] The inlaid sliding bearing has an inner diameter of 200 mm, and the inlaid hole 202 arranged on the sliding bearing has a diameter of 10 mm, and the total area of the inlaid hole 202 accounts for 28% of the inlaid surface area of the inlaid sliding bearing 20.

[0061] The inner oil groove 212 is in a circular arc shape, with a circular arc radius of 5 mm and an oil groove depth of 3 mm.

[0062] Experimental Example 1 verifies the lubricating effect of the composite solid lubricating material

[0063] The composite solid lubricating material of Example 1 (the material is in a cylindrical shape, with a bottom surface diameter of 10 mm) is inlaid in the inlaid hole 202 of the inlaid sliding bearing of Example 1, and together with the sealing ring 203, an inlaid sliding bearing containing a composite solid lubricating material is formed.

[0064] On a mining machine, the inlaid sliding bearing containing a composite solid lubricating material of Example 2, the inlaid sliding bearing containing a composite solid lubricating material of Example 1, the sliding bearing of Comparative Example 1, and a commonly used 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 whole is installed in the load bearing wheel of the present application as shown in Figure 3 The bolt 61 and the nut 62 are used for fixing. There are 5 load bearing wheels on each side of each electric forklift, and the sliding bearing of Example 1 and the CuSn10 comparative test piece are installed on the same electric forklift in corresponding positions on the left and right sides, to ensure that the performance is measured under the same conditions. The radial wear amount and the use effect are shown in Table 1.

[0065] Table 1 Performance comparison test results

[0066]

[0067] As shown in Table 1, after 150 days of experiment, the radial cumulative wear amount of the sliding bearing embedded with the composite solid lubricating material of the present application is only 28% of that of the commonly used copper alloy CuSn10 sliding bushing, achieving the goal of long lubrication period. Therefore, the inlaid sliding bearing containing a composite solid lubricating material of Example 1 of the present application, which is made of a copper alloy material with a grade of CuAl9Mn2, has a significantly better wear resistance than the commonly used copper alloy bushing.

[0068] In addition, the mosaic sliding bearing of Example 2 or the sliding bearing of Comparative Example 1 and the CuSn10 comparative test piece are installed on the same electric forklift truck, and the left and right corresponding positions are ensured to perform performance measurement under the same conditions. The test results show that the mosaic sliding bearing of Example 2 containing the composite solid lubricating material and made of the copper alloy material with the brand CuAl9Mn2 has the same wear resistance as that of Example 1. However, the wear resistance of the sliding bearing of Comparative Example 1 is close to that of the CuSn10 comparative test piece.

[0069] Although the present application has been described in detail by the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present application. Various modifications and alternatives to the present application will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present application should be defined by the appended claims.

Claims

1. An inlaid plain bearing comprising a composite solid lubricating material, characterized in that The mosaic sliding bearing is embedded with the composite solid lubricating material in the mosaic hole; the diameter of the mosaic hole is 3%~8% of the inner diameter of the mosaic sliding bearing, and the total area of the mosaic hole of the bearing is 20%~30% of the embedding surface area of the mosaic sliding bearing; The composite solid lubricating 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 mosaicked plain bearing according to claim 1, characterized in that The mass fraction of the metal copper powder is 14%~18%; the mass fraction of the graphite powder is 10%~12%.

3. The mosaicked plain bearing according to claim 1, 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 of producing the composite solid lubricating material as claimed in 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) compression molding the mixed powder to obtain a bulk material; (3) curing the bulk material; (4) cooling the cured bulk material to room temperature in air to obtain a composite solid lubricating material.

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

6. A load wheel assembly comprising the mosaic sliding bearing according to claim 1.

7. Use of the composite solid lubricating material or the mosaic sliding bearing according to any one of claims 1~3 or the load wheel assembly according to claim 6 in a mining machine.

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