Bearing and preparation method thereof, compressor and air conditioner

Abstract

The invention provides a bearing and a preparation method thereof, a compressor and an air conditioner, and the preparation method of the bearing comprises the following steps: sequentially carrying out powder mixing, compression molding, sintering and steam treatment on raw material powder of the bearing to obtain the bearing; raw material powder of the bearing at least comprises iron powder, graphite powder, copper powder and an antifriction additive, and the antifriction additive is used for reducing friction force between a cutting tool and the bearing when the bearing is cut.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to a bearing and a preparation method thereof, a compressor and an air conditioner. Background Art

[0002] The lower bearing is a common component of rotary refrigeration household air conditioner compressor products. It is used to support and rotate the compressor rotor so that the compressor can operate normally, thereby achieving cooling or heating of the air conditioner.

[0003] For a long time, the lower bearing component has been made of gray cast iron, produced using traditional casting technology, and combined with subsequent rough processing and finishing processes to produce finished products. This material and process model has been used for many years, but the dimensional accuracy of the casting blank is low, the subsequent processing procedures are complicated, the material utilization rate is low, and the casting production line is polluting and energy-consuming, with a high overall cost.

[0004] In recent years, the shortcomings of traditional casting processes such as high energy consumption and high pollution have gradually been exposed. Powder metallurgy technology has gradually been applied to multiple parts in the compressor industry due to its advantages such as energy saving and material reduction, high product precision and good stability. For example, rotary air conditioner compressor balance blocks, reciprocating refrigerator compressor valve plates, connecting rods, etc. In the long run, in compressors, powder metallurgy of some casting parts is an inevitable trend.

[0005] However, compared to the casting process, which uses block raw materials-high temperature melting-liquid-cooling-solid forming, the powder metallurgy process uses powder raw materials-solid particle pressing-high temperature sintering-partial low melting point material melting-fusion forming. The process characteristics of the two are essentially different. Compared with casting parts, the cutting life of the machining tools corresponding to powder metallurgy parts is insufficient. It is understandable that in the later processing of powder metallurgy parts, due to the large friction inside the bearing, the cutting resistance of the tool is increased, thereby reducing the service life of the machining tool. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0007] A first aspect of the present invention provides a bearing.

[0008] A second aspect of the present invention provides a method for preparing a bearing.

[0009] A third aspect of the present invention provides a compressor.

[0010] A fourth aspect of the present invention provides an air conditioner.

[0011] A first aspect of the present invention provides a bearing, which includes carbon, copper, manganese, sulfur, and iron, wherein the mass percentage of the carbon element in the bearing is greater than or equal to 0.6% and less than or equal to 1%; the mass percentage of the copper element in the bearing is greater than or equal to 1% and less than or equal to 2%; the mass percentage of the manganese element in the bearing is greater than or equal to 0.1% and less than or equal to 0.8%; the mass percentage of the sulfur element in the bearing is greater than or equal to 0.1% and less than or equal to 0.8%.

[0012] The present invention introduces manganese and sulfur elements into raw material powders, so that the manganese and sulfur elements can form manganese sulfide, which can reduce the friction between the cutting tool and the bearing when the bearing is cut, and can effectively reduce the friction coefficient during the tool processing process, thereby extending the service life of the tool. Due to the presence of manganese sulfide, there is no need to add additional lubricant during the cutting process, thereby improving the preparation efficiency.

[0013] In some technical solutions, optionally, the bearing includes carbon, copper, manganese, sulfur, and iron, wherein the mass percentage of carbon in the bearing is equal to 0.8%; the mass percentage of copper in the bearing is equal to 1.5%; the mass percentage of manganese in the bearing is equal to 0.5%; and the mass percentage of sulfur in the bearing is equal to 0.5%.

[0014] In this technical solution, controlling the proportion of each element in the raw materials of the bearing can improve the strength of the bearing while reducing the friction of the bearing and increasing the service life of the cutting tool.

[0015] In some technical solutions, optionally, the bearing further includes impurity elements, and the mass percentage of the impurity elements in the bearing is less than or equal to 1%.

[0016] In this technical solution, the bearing includes not only carbon, copper, manganese, sulfur, and iron, but also some impurity elements. The impurity elements mainly include metallic impurity elements and non-metallic impurity elements, which are mainly some auxiliary additive elements used to improve the strength, wear resistance, corrosion resistance, etc. of the bearing. Excluding the content of carbon, copper, manganese, sulfur, and impurity elements, the remainder is iron. Specifically, the content of iron is greater than or equal to 95% and less than or equal to 97%.

[0017] In some technical solutions, optionally, the density of the bearing is greater than or equal to 6.6 kg / m 3 , the hardness of the bearing is greater than or equal to 85HRB, and the tensile strength of the bearing is greater than or equal to 250MPa.

[0018] In this technical solution, the density, hardness and tensile strength of the bearing are limited, so that the bearing can have better comprehensive performance.

[0019] In some technical solutions, optionally, the metallographic matrix structure of the bearing includes pearlite, and the mass percentage of the pearlite in the metallographic matrix structure is greater than or equal to 60%.

[0020] In this technical solution, the mass percentage of pearlite in the bearing to the metallographic matrix structure is controlled to be greater than or equal to 60%, so that the bearing is not prone to defects and color differences. In addition, controlling the content of pearlite can significantly improve the strength and hardness of the bearing.

[0021] In some technical solutions, optionally, the surface of the bearing includes an oxide layer, the oxide layer includes Fe3O4, and the thickness of the oxide layer is greater than or equal to 7 μm and less than or equal to 15 μm.

[0022] In this technical solution, Fe3O4 is used as a protective layer of the bearing to improve the corrosion resistance, heat resistance and impact resistance of the bearing, prevent the iron element in the bearing from being oxidized, and increase the service life of the bearing. Controlling the thickness of the oxide layer can prevent the problem of the protective layer being too thick to affect the color of the bearing surface, and can also avoid the problem of the protective layer being too thin to have a poor protective effect.

[0023] In some technical solutions, optionally, the friction coefficient of the bearing is greater than or equal to 0.07 and less than or equal to 0.09, which indicates that the bearing of the present invention has a lower friction force, so that the resistance of the cutting knife can be reduced during the processing and cutting process, the service life of the cutting knife can be increased, and the processing efficiency can be improved. Optionally, the friction coefficient of the bearing is equal to 0.08.

[0024] The second aspect of the present invention provides a method for preparing a bearing, comprising: sequentially mixing, pressing, sintering and steam treating the raw material powder of the bearing to obtain the bearing; the raw material powder of the bearing contains at least iron powder, graphite powder, copper powder and anti-friction additives, and the anti-friction additives are used to reduce the friction between the cutting tool and the bearing when the bearing is cut.

[0025] The present invention introduces a friction-reducing additive with a friction-reducing and lubricating effect into the raw material powder. The friction-reducing additive can reduce the friction between the cutting tool and the bearing when the bearing is cut, and can effectively reduce the friction coefficient during the tool processing process, thereby extending the service life of the tool. Due to the presence of the friction-reducing additive, no additional lubricant needs to be added during the cutting process, thereby improving the preparation efficiency. In addition, the present invention adopts process steps such as press molding and sintering to prepare the bearing. Compared with the conventional casting process, the component utilization rate is high, the consistency of the bearing is stable, and the bearing surface is more uniform.

[0026] In some technical solutions, optionally, the friction reducing additive includes at least one of the following or a combination thereof: manganese sulfide, calcium fluoride, lithium stearate, molybdenum disulfide.

[0027] In some technical solutions, optionally, the raw material powder of the bearing also includes a lubricating additive, and the lubricating additive is used to reduce the friction between the bearing and the pressing mold in the pressing step.

[0028] In this technical solution, the raw material powder also includes a lubricating additive, so that in the pressing step, the lubricating additive can reduce the friction between the bearing and the pressing mold, which can make demolding easier on the one hand and increase the smoothness of the bearing surface on the other hand.

[0029] In some technical solutions, optionally, the lubricating additive includes at least one of the following or a combination thereof: sulfurized isobutylene, phosphate ester, phosphite, and chlorinated paraffin.

[0030] In some technical solutions, optionally, the iron powder includes at least one of the following or a combination thereof: atomized iron powder, reduced iron powder.

[0031] In this technical solution, atomized iron powder and / or reduced iron powder are used as the iron element, which can reduce the oxygen content that is unfavorable to tool wear and cutting performance, thereby reducing the friction coefficient during tool processing, thereby having a longer tool cutting service life.

[0032] In some technical solutions, optionally, the copper powder includes electrolytic copper powder.

[0033] In this technical solution, electrolytic copper powder is used as the copper element in order to reduce the oxygen content which is unfavorable to tool wear and cutting performance, thereby reducing the friction coefficient during tool processing, thereby having a longer tool cutting service life.

[0034] In some technical schemes, optionally, when the iron powder includes atomized iron powder and reduced iron powder, the mass percentage of the atomized iron powder in the bearing is greater than or equal to 22% and less than or equal to 32%; the mass percentage of the reduced iron powder in the bearing is greater than or equal to 62% and less than or equal to 72%; the mass percentage of the graphite powder in the bearing is greater than or equal to 0.6% and less than or equal to 1%; the mass percentage of the electrolytic copper powder in the bearing is greater than or equal to 1% and less than or equal to 2%; the mass percentage of the friction-reducing additive in the bearing is greater than or equal to 0.2% and less than or equal to 1.6%.

[0035] In this technical solution, controlling the proportion of each element in the raw materials of the bearing can improve the strength of the bearing while reducing the friction of the bearing and increasing the service life of the cutting tool.

[0036] In some technical solutions, optionally, in the step of mixing the powders, the mixing time is greater than or equal to 30 minutes and less than or equal to 60 minutes.

[0037] In this technical solution, controlling the mixing time can improve the uniformity of the components, thereby making the prepared bearing have more uniform internal structural properties.

[0038] In some technical solutions, optionally, in the step of press molding, the pressing pressure is greater than or equal to 600 MPa and less than or equal to 1200 MPa.

[0039] In this technical solution, controlling the appropriate pressing pressure can make the grain size more uniform, the elements more closely combined, and the porosity reduced, thereby improving the strength of the bearing. Too little pressure will lead to uneven sintered body structure and unclear grain boundaries, while too much pressure will cause deformation of the grains and reduce the performance of the bearing.

[0040] In some technical solutions, optionally, in the sintering step, the sintering temperature is greater than or equal to 1120° C. and less than or equal to 1160° C., and the sintering time is greater than or equal to 3 hours and less than or equal to 4 hours.

[0041] In this technical solution, controlling the sintering temperature and sintering time can improve the density, strength and hardness of the sintered body, avoid over-burning due to too high sintering temperature and too long sintering time, and avoid too low sintering temperature and too short sintering time, which lead to low density of the sintered body and unsatisfactory properties such as strength and hardness.

[0042] In some technical solutions, optionally, in the steam treatment step, the steam treatment temperature is greater than or equal to 530° C. and less than or equal to 580° C., and the treatment time is greater than or equal to 8 hours and less than or equal to 12 hours.

[0043] In this technical solution, by controlling the time and temperature of steam treatment, a dense oxide film can be formed on the surface of the bearing, thereby improving the corrosion resistance, heat resistance and impact resistance of the bearing, preventing the iron elements in the bearing from being oxidized, and increasing the service life of the bearing.

[0044] A third aspect of the present invention provides a compressor, and the compressor provided by the present invention includes the bearing provided by any technical solution of the first aspect of the present invention.

[0045] A fourth aspect of the present invention provides an air conditioner. The air conditioner provided by the present invention includes the bearing provided by any technical solution of the first aspect of the present invention, or includes the compressor provided by the third aspect of the present invention.

[0046] Additional aspects and advantages of the present invention will become apparent in the following description or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and / or additional aspects and advantages of the embodiments of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0048] Figure 1 A schematic diagram of the preparation process of a bearing preparation method provided in the first embodiment of the present invention is shown;

[0049] Figure 2 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 1 of the present invention is shown;

[0050] Figure 3 A bar graph showing a density comparison between the bearing provided in Example 1 of the present invention and the bearing provided in Comparative Example 1 is shown;

[0051] Figure 4 A bar graph comparing the hardness of the bearing provided by Example 1 of the present invention and the bearing provided by Comparative Example 1 is shown;

[0052] Figure 5 A comparative bar graph of the friction coefficients of the bearing provided by the first embodiment of the present invention and the bearing provided by the first comparative example is shown;

[0053] Figure 6 A bar chart comparing the number of times a tool processes a bearing provided in Example 1 of the present invention and a bearing provided in Comparative Example 1;

[0054] Figure 7 The tool state diagram before and after the tool processes the bearing provided by the first embodiment of the present invention is shown;

[0055] Figure 8 The tool state diagram before and after the bearing machining provided by the tool comparison example 1 is shown;

[0056] Fig. 9 A schematic diagram of the preparation process of a bearing preparation method provided in the second embodiment of the present invention is shown;

[0057] Fig.10 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 3 of the present invention is shown;

[0058] Fig.11 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 4 of the present invention is shown;

[0059] Fig.12 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 2 of the present invention is shown;

[0060] Fig.13 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 3 of the present invention is shown;

[0061] Fig.14 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 4 of the present invention is shown;

[0062] Fig.15 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 5 of the present invention is shown;

[0063] Fig.16 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 6 of the present invention is shown;

[0064] Fig.17 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 7 of the present invention is shown;

[0065] Fig.18 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 5 of the present invention is shown;

[0066] Fig.19 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 6 of the present invention is shown;

[0067] Fig. 20 A schematic diagram of the preparation process of a bearing preparation method provided in Comparative Example 7 of the present invention is shown;

[0068] Fig.21 A schematic diagram of the preparation process of a bearing preparation method provided in Embodiment 8 of the present invention is shown. DETAILED DESCRIPTION

[0069] In order to more clearly understand the above aspects, features and advantages of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0070] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments according to the present invention. However, the embodiments according to the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the embodiments according to the present invention is not limited to the specific embodiments disclosed below.

[0071] According to some embodiments of the present invention, a bearing is provided, and the bearing provided by the present invention includes carbon, copper, manganese, sulfur, and iron, wherein the carbon element accounts for 0.6% to 1% of the total mass; the copper element accounts for 1% to 2% of the total mass; the manganese element accounts for 0.1% to 0.8% of the total mass; and the sulfur element accounts for 0.1% to 0.8% of the total mass. Optionally, the carbon element accounts for 0.8% of the total mass; the copper element accounts for 1.5% of the total mass; the manganese element accounts for 0.5% of the total mass; and the sulfur element accounts for 0.5% of the total mass. Controlling the proportion of each element in the raw materials of the bearing can improve the strength of the bearing, reduce the friction of the bearing, and increase the service life of the cutting tool.

[0072] In some embodiments, optionally, the bearing further includes impurity elements, and the ratio of the impurity elements to the total mass is less than or equal to 1%. The bearing includes not only carbon, copper, manganese, sulfur, and iron, but also some impurity elements, and the impurity elements mainly include metallic impurity elements and non-metallic impurity elements, which are mainly some auxiliary additive elements used to improve the strength, wear resistance, corrosion resistance, etc. of the bearing, and the balance is iron.

[0073] In some embodiments, optionally, the density of the bearing is greater than or equal to 6.6 kg / m 3 , optional, the bearing density is greater than or equal to 8kg / m 3 , the hardness of the bearing is greater than or equal to 85HRB, optionally, the hardness of the bearing is greater than or equal to 95HRB, the tensile strength of the bearing is greater than or equal to 250MPa, optionally, the tensile strength of the bearing is greater than or equal to 280MPa. Limiting the density, hardness and tensile strength of the bearing can make the bearing have better comprehensive performance.

[0074] In some embodiments, the metallographic matrix structure of the bearing includes pearlite, and the pearlite content is at least 60%. Controlling the mass percentage of the pearlite in the bearing to be greater than or equal to 60% of the mass percentage of the metallographic matrix structure can make the bearing less prone to defects and color difference. In addition, controlling the content of pearlite can significantly improve the strength and hardness of the bearing.

[0075] In some embodiments, optionally, the surface of the bearing includes an oxide layer, the oxide layer is Fe3O4, and the thickness of the oxide layer is 7 μm to 15 μm. By using Fe3O4 as a protective layer for the bearing, the corrosion resistance, heat resistance and impact resistance of the bearing can be improved, the iron element in the bearing can be prevented from being oxidized, and the service life of the bearing can be increased. Controlling the thickness of the oxide layer can prevent the problem of the protective layer being too thick to affect the color of the bearing surface, and can also avoid the problem of the protective layer being too thin and having a poor protective effect.

[0076] In some embodiments, optionally, the friction coefficient of the bearing is 0.07 to 0.09, indicating that the bearing of the present invention has a relatively low friction force, so that the resistance of the cutting blade can be reduced during the machining and cutting process, the service life of the cutting blade can be increased, and the machining efficiency can be improved. Optionally, the friction coefficient of the bearing is equal to 0.08.

[0077] Some embodiments and comparative examples of the present invention provide methods for preparing bearings.

[0078] Embodiment 1

[0079] like Figure 1 As shown, this embodiment provides a method for preparing a bearing, comprising the following steps:

[0080] S102: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.6% manganese, 0.6% sulfur, less than 1% impurity elements, and the balance is iron;

[0081] S104: pressing the mixed powder at a pressure of 900 MPa;

[0082] S106: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0083] S108: Finally, steam treatment is performed to obtain a bearing.

[0084] Comparative Example 1

[0085] like Figure 2 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0086] S202: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon element, 1.5% copper element, less than 1% impurity element, and the balance is iron element;

[0087] S204: pressing the mixed powder at a pressure of 900 MPa;

[0088] S206: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0089] S208: Finally, steam treatment is performed to obtain a bearing.

[0090] That is, the formula and process parameters of Comparative Example 1 and Example 1 are shown in Table 1 below:

[0091]

[0092] Table 1

[0093] The density and hardness of the bearings prepared in Example 1 and Comparative Example 1 of the present invention were tested. The test results are as follows: Figure 3 and Figure 4 As shown, according to Figure 3 and Figure 4 It can be seen that whether the raw material powder includes manganese and sulfur elements has little effect on the density and hardness of the bearing.

[0094] The friction force of the bearings prepared in Example 1 and Comparative Example 1 of the present invention was tested. The test results are as follows: Figure 5 As shown, according to Figure 5 It can be seen that the raw material powder includes manganese and sulfur elements, so that manganese and sulfur elements can produce manganese sulfide, and manganese sulfide can play a certain lubricating role, which greatly reduces the friction coefficient inside the bearing. The friction coefficient of the bearing prepared by the method of the present invention is about 0.09, which is less than the friction coefficient of the bearing prepared by the comparative example method of 0.104, thereby improving the service life of the machining tool.

[0095] The production line tool life verification test was carried out on the bearings prepared in Example 1 of the present invention and Comparative Example 1, wherein the parameter records of the tool when processing the bearing prepared in Example 1 of the present invention are shown in Table 2, and the parameter records of the tool when processing the bearing prepared in Comparative Example 1 are shown in Table 3:

[0096]

[0097] Table 2

[0098]

[0099] Table 3

[0100] According to Table 2 and Table 3, it can be seen that the number of bearings prepared in Example 1 that can be processed by the tool is 3804, while the number of bearings prepared in Comparative Example 1 that can be processed is only 2445. The number of bearings prepared in Example 1 that can be processed exceeds the number of bearings prepared in Comparative Example 1 by 55%. The bar chart of the number of processing is shown in FIG. Figure 6 As shown, in addition, the cutter before and after processing the 3804 bearings prepared in the first embodiment has a cross-sectional view as shown in FIG. Figure 7 As shown, the cutter is used to process 2445 bearings prepared in comparative example 1 before and after processing, and its cross-sectional view is as follows Figure 8 As shown, according to Figure 8 It can be seen that after the tool was used to process 2445 bearings prepared in comparative example 1, there was a large fracture at the tip of the tool. Figure 7It can be seen that after the tool processed 3804 bearings prepared in the first embodiment of the present invention, there was only a tiny fracture at the tip of the tool. This shows that after the friction-reducing additive with friction-reducing and lubricating effect is added to the raw material powder, the friction-reducing additive can reduce the friction between the cutting tool and the bearing when the bearing is cut, and can effectively reduce the friction coefficient during the tool processing process, thereby extending the service life of the tool.

[0101] The lubrication mechanism of the present invention is that due to the presence of S and Mn elements in the raw material components, MnS can be formed during the sintering process. MnS exists as a free-cutting agent powder, and the MnS free-cutting agent powder is mainly distributed near the sintering neck of the iron-based particles or in the pores between the particles, and mainly plays a chip breaking role. When the cutting edge contacts the MnS, the drill chips break. Due to their small shape, they are easier to be discharged from the hole, which can significantly compensate for the additional impact of the pores, reduce the adverse effects of the cutting speed on the main cutting force and the tool life, reduce tool wear, and also have the functions of improving the lubrication performance of the metal surface, improving the smoothness of the processed metal surface, and playing the role of a solid lubricant.

[0102] Embodiment 2

[0103] like Fig. 9 As shown, this embodiment provides a method for preparing a bearing, comprising the following steps:

[0104] S302: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.5% manganese, 0.5% sulfur, less than 1% impurity elements, and the balance is iron;

[0105] S304: pressing the mixed powder at a pressure of 900 MPa;

[0106] S306: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0107] S308: Finally, steam treatment is performed to obtain a bearing.

[0108] Embodiment 3

[0109] like Fig.10 As shown, this embodiment provides a method for preparing a bearing, comprising the following steps:

[0110] S402: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.4% manganese, 0.4% sulfur, less than 1% impurity elements, and the balance is iron;

[0111] S404: pressing the mixed powder at a pressure of 900 MPa;

[0112] S406: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0113] S408: Finally, steam treatment is performed to obtain a bearing.

[0114] Embodiment 4

[0115] like Fig.11 As shown, this embodiment provides a method for preparing a bearing, comprising the following steps:

[0116] S502: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.4% manganese, 0.6% sulfur, less than 1% impurity elements, and the balance is iron;

[0117] S504: pressing the mixed powder at a pressure of 900 MPa;

[0118] S506: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0119] S508: Finally, steam treatment is performed to obtain a bearing.

[0120] Comparative Example 2

[0121] like Fig.12 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0122] S602: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.05% manganese, 0.6% sulfur, less than 1% impurity elements, and the balance is iron;

[0123] S604: pressing the mixed powder at a pressure of 900 MPa;

[0124] S606: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0125] S608: Finally, steam treatment is performed to obtain a bearing.

[0126] Comparative Example 3

[0127] like Fig.13 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0128] S702: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 0.6% manganese, 0.05% sulfur, less than 1% impurity elements, and the balance is iron;

[0129] S704: pressing the mixed powder at a pressure of 900 MPa;

[0130] S706: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0131] S708: Finally, steam treatment is performed to obtain a bearing.

[0132] Comparative Example 4

[0133] like Fig.14 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0134] S802: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing contain 0.9% carbon, 1.5% copper, 1.0% manganese, 1.0% sulfur, less than 1% impurity elements, and the balance is iron;

[0135] S804: Pressing the mixed powder at a pressure of 900 MPa;

[0136] S806: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0137] S808: Finally, steam treatment is performed to obtain a bearing.

[0138] That is, the formulas and process parameters of Examples 2 to 4 and Comparative Examples 2 to 4 are shown in Table 4 below:

[0139]

[0140] Table 4

[0141] The density, hardness, friction and service life of the bearings prepared in Examples 2 to 4 of the present invention and Comparative Examples 2 to 4 were tested in turn, and the results are shown in Table 5 below:

[0142] density hardness Friction coefficient Service life Embodiment 1 6.9 89 0.09 3804 Embodiment 2 6.8 89 0.092 3758 Embodiment 3 6.9 88 0.093 3769 Embodiment 4 6.9 89 0.091 3810 Comparative Example 2 6.8 88 0.105 2480 Comparative Example 3 6.8 87 0.104 2465 Comparative Example 4 6.9 89 0.12 2359

[0143] Table 5

[0144] According to Table 5, the contents of sulfur and manganese in Examples 2 to 4 are appropriate, so that the bearing lubrication effect is better. In Comparative Example 2, the manganese element is too little, and in Comparative Example 3, the sulfur element is too little, which leads to a small content of manganese sulfide generated, resulting in a poor lubrication effect, while the density and hardness are equivalent to those in Example 1. In Comparative Example 4, excessive manganese and sulfur elements will also increase the friction coefficient. In addition, it will make the bearing more brittle and fail to meet the standard.

[0145] Embodiment 5

[0146] like Fig.15 As shown, some embodiments of the present invention provide a method for preparing a bearing, comprising the following steps:

[0147] S902: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 70% atomized iron powder, 26% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0148] S904: pressing the mixed powder at a pressure of 900 MPa;

[0149] S906: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0150] S908: Finally, steam treatment is performed to obtain a bearing.

[0151] Embodiment 6

[0152] like Fig.16 As shown, some embodiments of the present invention provide a method for preparing a bearing, comprising the following steps:

[0153] S1002: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 72% atomized iron powder, 24% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0154] S1004: pressing the mixed powder at a pressure of 900 MPa;

[0155] S1006: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0156] S1008: Finally, steam treatment is performed to obtain the bearing.

[0157] Embodiment 7

[0158] like Fig.17 As shown, some embodiments of the present invention provide a method for preparing a bearing, comprising the following steps:

[0159] S1102: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 66% atomized iron powder, 30% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0160] S1104: pressing the mixed powder at a pressure of 900 MPa;

[0161] S1106: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0162] S1108: Finally, steam treatment is performed to obtain a bearing.

[0163] Comparative Example 5

[0164] like Fig.18 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0165] S1202: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 46% atomized iron powder, 50% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0166] S1204: pressing the mixed powder at a pressure of 900 MPa;

[0167] S1206: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0168] S1208: Finally, steam treatment is performed to obtain a bearing.

[0169] Comparative Example 6

[0170] like Fig.19 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0171] S1302: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 40% atomized iron powder, 56% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0172] S1304: Pressing the mixed powder at a pressure of 900 MPa;

[0173] S1306: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0174] S1308: Finally, steam treatment is performed to obtain a bearing.

[0175] Comparative Example 7

[0176] like Fig. 20 As shown, this comparative example provides a method for preparing a bearing, comprising the following steps:

[0177] S1402: firstly, mixing raw material powders of the bearing; wherein the raw material powders of the bearing include 35% atomized iron powder, 61% reduced iron powder, 1% graphite powder, 1.5% electrolytic copper powder, and 1.5% friction reducing additive;

[0178] S1404: pressing the mixed powder at a pressure of 900 MPa;

[0179] S1406: Sintering the pressed material at a temperature of 1140° C. for 3.5 hours;

[0180] S1408: Finally, steam treatment is performed to obtain a bearing.

[0181] That is, the formulas and process parameters of Examples 5 to 7 and Comparative Examples 5 to 7 are shown in Table 6 below:

[0182]

[0183] Table 6

[0184] The friction force and service life of the bearings prepared in Examples 5 to 7 of the present invention and Comparative Examples 5 to 7 were tested in turn, and the results are shown in Table 7 below:

[0185] Friction coefficient Service life Embodiment 5 0.092 3785 Embodiment 6 0.090 3800 Embodiment 7 0.091 3798 Comparative Example 5 0.107 2560 Comparative Example 6 0.106 2400 Comparative Example 7 0.103 2320

[0186] Table 7

[0187] According to Table 7, the proportion of atomized iron powder in Examples 5 to 7 is relatively large, which can reduce the oxygen content that is unfavorable to tool wear and cutting performance, thereby reducing the friction coefficient during tool processing, thereby having a longer tool cutting service life. In Comparative Examples 5 to 7, the proportion of reduced iron powder is relatively large, resulting in a higher oxygen content in the bearing, so the friction coefficient is relatively large and the tool service life is short.

[0188] Embodiment 8

[0189] like Fig.21 As shown, this embodiment provides a method for preparing a bearing, comprising the following steps:

[0190] S1502: firstly mixing raw material powders of the bearing; wherein the raw material powders of the bearing at least include iron powder, graphite powder, copper powder and friction reducing additives;

[0191] S1504: Pressing the mixed powder;

[0192] S1506: Sintering the pressed material;

[0193] S1508: Finally, steam treatment is performed to obtain a bearing.

[0194] The present invention introduces a friction-reducing additive with a friction-reducing and lubricating effect into the raw material powder. The friction-reducing additive can reduce the friction between the cutting tool and the bearing when the bearing is cut, and can effectively reduce the friction coefficient during the tool processing process, thereby extending the service life of the tool. Due to the presence of the friction-reducing additive, no additional lubricant needs to be added during the cutting process, thereby improving the preparation efficiency. In addition, compared with conventional casting processes, the present invention adopts process steps such as pressing and sintering to prepare bearings, which has high component utilization, stable bearing consistency, and more uniform bearing surface.

[0195] In some embodiments, the friction reducing additive may optionally include at least one of manganese sulfide, calcium fluoride, lithium stearate, and molybdenum disulfide.

[0196] In some embodiments, optionally, the raw material powder also includes a lubricating additive, so that in the pressing step, the lubricating additive can reduce the friction between the bearing and the pressing mold, which can make demolding easier on the one hand and increase the smoothness of the bearing surface on the other hand.

[0197] In some embodiments, the lubricating additive may optionally include at least one of sulfurized isobutylene, phosphate ester, phosphite, and chlorinated paraffin.

[0198] In some embodiments, the iron powder may be atomized iron powder, reduced iron powder, or a mixed iron powder of atomized iron powder and reduced iron powder. Atomized iron powder and / or reduced iron powder are used as the iron element, so that the oxygen content that is unfavorable to tool wear and cutting performance can be reduced, thereby reducing the friction coefficient during tool processing, thereby having a longer tool cutting service life.

[0199] In some embodiments, optionally, the copper powder can be electrolytic copper powder. The use of electrolytic copper powder as the copper element is also to reduce the oxygen content that is unfavorable to tool wear and cutting performance, thereby reducing the friction coefficient during tool processing, thereby having a longer tool cutting service life.

[0200] In some embodiments, optionally, when the iron powder includes atomized iron powder and reduced iron powder, the atomized iron powder accounts for 22% to 32%. The reduced iron powder accounts for 62% to 72%. The graphite powder accounts for 0.6% to 1%. The electrolytic copper powder accounts for 1% to 2%. The friction reducing additive accounts for 0.2% to 1.6%. Controlling the proportion of each element in the raw materials of the bearing can improve the strength of the bearing while reducing the friction of the bearing and increasing the service life of the cutting tool.

[0201] In some embodiments, optionally, in the step of mixing the powders, the mixing time is 30 minutes to 60 minutes. Controlling the mixing time can improve the uniformity of the components, thereby making the prepared bearing have more uniform internal structure properties.

[0202] In some embodiments, optionally, in the step of pressing and forming, the pressing pressure is 600 MPa to 1200 MPa. Controlling the appropriate pressing pressure can make the grain size more uniform, the elements more closely combined, and the porosity reduced, thereby improving the strength of the bearing. Too little pressure will lead to uneven sintered body structure and unclear grain boundaries, and too much pressure will cause deformation of the grains, thereby reducing the performance of the bearing.

[0203] In some embodiments, optionally, in the sintering step, the sintering temperature is 1120° C. to 1160° C., and the sintering time is 3 hours to 4 hours. Controlling the sintering temperature and sintering time can improve the density, strength and hardness of the sintered body, avoid the phenomenon of over-burning caused by too high sintering temperature and too long sintering time, and avoid the problem of low density of the sintered body and substandard performance such as strength and hardness caused by too low sintering temperature and too short sintering time.

[0204] In some embodiments, optionally, in the step of steam treatment, the steam treatment temperature is 530° C. to 580° C., and the treatment time is 8 hours to 12 hours. Controlling the time and temperature of the steam treatment can form a dense oxide film on the surface of the bearing, improve the corrosion resistance, heat resistance and impact resistance of the bearing, prevent the iron elements in the bearing from being oxidized, and increase the service life of the bearing.

[0205] According to some embodiments of the present application, a powder metallurgy lower bearing is provided, wherein the element composition and mass fraction percentage of the lower bearing are as follows: C 0.6%-1.0%, Cu 1.0%-2.0%, Mn 0.3%-0.8%, other elements ≤1.5%, and the balance is Fe, based on the total mass as 100%;

[0206] Optional, lower bearing density ≥ 6.6kg / m 3 , hardness ≥85HRB, tensile strength ≥250MPa;

[0207] Optionally, the metallographic structure of the lower bearing is based on pearlite, and the pearlite content is ≥ 60%;

[0208] Optionally, the surface of the lower bearing is steam treated, and the main component of the oxide after the surface treatment is Fe3O4, and the thickness of the oxide layer is 7um to 15um;

[0209] According to some embodiments of the present invention, there is provided a method for preparing a powder metallurgy lower bearing, comprising the following main steps: mixing raw material powders, pressing and forming, high temperature sintering, and steam treatment;

[0210] Optionally, the raw material powders include at least six kinds of powders: atomized iron powder, reduced iron powder, graphite powder, electrolytic copper powder, lubricating additives, and friction reducing additives. After various raw material powders are prepared according to the required formula, they are loaded into a mixer for mixing, and the mixing time is 30 minutes to 60 minutes.

[0211] Optionally, the mixed powder is pressed by a mechanical press or an oil hydraulic press to obtain a compact, and the pressing pressure is 600 MPa to 1200 MPa;

[0212] Optionally, the compact is subjected to high-temperature sintering treatment in a push boat furnace or a mesh bag furnace to obtain a sintered product, the maximum sintering temperature is 1120° C. to 1160° C., and the sintering time is 3 h to 4 h;

[0213] Optionally, the sintered product is steam treated in a pit steam treatment furnace, during which water vapor is introduced to form Fe3O4, the maximum treatment temperature is 530°C to 580°C, and the treatment time is 8h to 12h;

[0214] Compared with the comparative example, the present invention introduces additive powder with friction-reducing and lubricating effects in the material formula and preparation method. Under the same pressing and sintering process conditions, the density, hardness and other technical indicators of the corresponding bearings in the embodiment are maintained at a comparable level to those in the comparative example. The laboratory friction and wear performance results show that the friction coefficient of the corresponding samples in the embodiment is lower. The actual tool processing verification results of the production line show that the tool processing life of the embodiment is increased by more than 50% compared with that of the comparative example.

[0215] According to some embodiments of the present invention, a compressor is provided. The compressor provided by the present invention includes the bearing provided by any of the above embodiments, and therefore has all the beneficial effects of the bearing, which will not be repeated here.

[0216] Optionally, the compressor of the present invention is a rotary refrigeration and air-conditioning compressor.

[0217] According to some embodiments of the present invention, an air conditioner is provided. The air conditioner provided by the present invention includes the bearing provided by any of the above embodiments, or includes the compressor provided by any of the above embodiments. Therefore, all the beneficial effects of having the bearing or the compressor are not repeated here.

[0218] In the embodiments according to the present invention, the terms "first", "second", and "third" are only used for description and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments according to the present invention can be understood according to specific circumstances.

[0219] In addition, although each operation is described in a specific order, this should be understood as requiring such operation to be performed in a specific order or in a sequential order, or requiring that all illustrated operations should be performed to obtain desired results. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present invention. Some features described in the context of a separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation can also be implemented in multiple implementations individually or in any suitable sub-combination mode.

[0220] Although the subject matter has been described in the language of specific structural features and / or method logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims. The above are only preferred embodiments according to the embodiments of the present invention and are not intended to limit the embodiments of the present invention. For those skilled in the art, various changes and variations may be made according to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. A bearing, characterized in that: The bearing includes carbon, copper, manganese, sulfur and iron, wherein: The mass percentage of the carbon element in the bearing is greater than or equal to 0.6% and less than or equal to 1%; The mass percentage of the copper element in the bearing is greater than or equal to 1% and less than or equal to 2%; The mass percentage of the manganese element in the bearing is greater than or equal to 0.1% and less than or equal to 0.8%; The mass percentage of the sulfur element in the bearing is greater than or equal to 0.1% and less than or equal to 0.8%.

2. The bearing according to claim 1, characterized in that: The bearing further comprises impurity elements, and the mass percentage of the impurity elements in the bearing is less than or equal to 1%.

3. The bearing according to claim 1, characterized in that: The density of the bearing is greater than or equal to 6.6 kg / m 3 The hardness of the bearing is greater than or equal to 85HRB, and the tensile strength of the bearing is greater than or equal to 250MPa.

4. The bearing according to claim 1, characterized in that: The metallographic matrix structure of the bearing includes pearlite, and the mass percentage of the pearlite in the metallographic matrix structure is greater than or equal to 60%.

5. The bearing according to claim 1, characterized in that: The surface of the bearing comprises an oxide layer, and the thickness of the oxide layer is greater than or equal to 7 μm and less than or equal to 15 μm.

6. The bearing according to claim 5, characterized in that: The oxide layer includes Fe3O4.

7. The bearing according to claim 1, characterized in that The friction coefficient of the bearing is greater than or equal to 0.07 and less than or equal to 0.

09.

8. A method for preparing a bearing, characterized in that: include: The raw material powder of the bearing is sequentially subjected to powder mixing, pressing, sintering and steam treatment to obtain the bearing; The raw material powder of the bearing at least comprises iron powder, graphite powder, copper powder and a friction reducing additive, and the friction reducing additive is used to reduce the friction between the cutting tool and the bearing when the bearing is cut.

9. The method for preparing a bearing according to claim 8, characterized in that: The friction reducing additive includes at least one of the following or a combination thereof: manganese sulfide, calcium fluoride, lithium stearate, and molybdenum disulfide.

10. The method for preparing a bearing according to claim 8, characterized in that: The raw material powder of the bearing further includes a lubricating additive for reducing friction between the bearing and a pressing die in the step of pressing.

11. The method for preparing a bearing according to claim 10, characterized in that: The lubricating additive comprises at least one of the following or a combination thereof: sulfided isobutylene, phosphate ester, phosphite, and chlorinated paraffin.

12. The method for preparing a bearing according to claim 8, characterized in that: The iron powder includes at least one of the following or a combination thereof: atomized iron powder, reduced iron powder; The copper powder includes electrolytic copper powder.

13. The method for preparing a bearing according to claim 12, characterized in that: In the case where the iron powder includes atomized iron powder and reduced iron powder, The mass percentage of the atomized iron powder in the bearing is greater than or equal to 22% and less than or equal to 32%; The mass percentage of the reduced iron powder in the bearing is greater than or equal to 62% and less than or equal to 72%; The mass percentage of the graphite powder in the bearing is greater than or equal to 0.6% and less than or equal to 1%; The mass percentage of the electrolytic copper powder in the bearing is greater than or equal to 1% and less than or equal to 2%; The mass percentage of the friction-reducing additive in the bearing is greater than or equal to 0.2% and less than or equal to 1.6%.

14. The method for preparing a bearing according to any one of claims 8 to 13, characterized in that: In the step of mixing the powders, the mixing time is greater than or equal to 30 minutes and less than or equal to 60 minutes; and / or In the step of pressing and forming, the pressing pressure is greater than or equal to 600 MPa and less than or equal to 1200 MPa; and / or In the sintering step, the sintering temperature is greater than or equal to 1120° C. and less than or equal to 1160° C., and the sintering time is greater than or equal to 3 hours and less than or equal to 4 hours; and / or In the steam treatment step, the steam treatment temperature is greater than or equal to 530° C. and less than or equal to 580° C., and the treatment time is greater than or equal to 8 hours and less than or equal to 12 hours.

15. A compressor, characterized in that: Comprising the bearing according to any one of claims 1 to 7.

16. An air conditioner, characterized in that: include: A compressor as claimed in claim 15; or A bearing as claimed in any one of claims 1 to 7.

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