Bearing retainer pipe blank, manufacturing method of bearing retainer pipe blank, bearing retainer and manufacturing method of bearing retainer

Abstract

The invention relates to a bearing retainer blank and a manufacturing method thereof, and further relates to a bearing retainer manufactured by the blank and a corresponding manufacturing method. According to the method, the pipe blank which is excellent in machining performance and can meet the performance requirement of the bearing retainer in the wind power field can be obtained by optimizing the blank components and the pipe manufacturing process, and compared with a conventional process, the method for manufacturing the bearing retainer through the pipe blank can reduce the manufacturing steps, so that the manufacturing process can be simplified, and the production efficiency can be improved; and the manufactured bearing retainer has good mechanical performance and meets the durability requirement of the wind power field.

Description

Technical Field

[0001] This invention relates to the field of bearing manufacturing technology, specifically to a bearing cage blank and its manufacturing method, and a bearing cage and its manufacturing method. Background Technology

[0002] Bearing cages are indispensable key components in rolling bearings. Their core function is to precisely separate and evenly space the rolling elements, guiding them to move along the correct trajectory, thereby effectively preventing energy loss, abnormal wear, and heat generation caused by direct contact, collision, and friction between the rolling elements. Wind power equipment generally requires maintenance-free operation for more than 20 years, which places extremely high demands on the performance and dimensional accuracy of the bearing cage, a critical component. Referring to Chinese patent CN113464554B, for cylindrical and tapered bearing cages, existing processes use sheet metal to create high-strength, uniformly consistent cylindrical blanks to meet machining requirements. In contrast, using steel pipes as blanks to manufacture bearing cages theoretically eliminates many processes and offers high material utilization, showing promising application prospects. However, existing pipe materials cannot simultaneously meet the relevant machining requirements as well as the performance and durability requirements of bearing cages in the wind power field. Related blank materials and manufacturing processes still need further development and improvement. Summary of the Invention

[0003] The first objective of this invention is to provide a method for manufacturing a bearing cage blank that is adapted to relevant machining and stamping processes.

[0004] A second objective of the present invention is to provide a bearing cage blank produced by the aforementioned method.

[0005] A third objective of this invention is to provide a method for manufacturing a bearing cage using the aforementioned bearing cage blank.

[0006] A fourth objective of this invention is to provide a bearing cage manufactured by the aforementioned method.

[0007] To achieve the aforementioned first objective, the present invention provides a method for manufacturing a bearing cage blank, characterized by comprising the following steps: Step S10: The round billet for tube making is subjected to piercing, continuous rolling, sizing, and cooling to obtain a seamless tube. The round billet for tube making includes Fe, C, Mn, Si, P, S, and Al elements. By weight percentage, the C element content in the round billet for tube making is 0.02~0.2%, the Mn element content is 0.1~1.8%, the Si element content is ≤1%, the P element content is ≤0.03%, the S element content is ≤0.03%, and the Al element content is ≤0.04%. Step S20: Normalize or quench and temper the seamless tube to obtain the mother tube; Step S30: The mother tube is cold-drawn or cold-rolled to obtain a cold-formed tube; Step S40: Anneal the cold-formed tube to obtain a bearing cage blank with a residual stress value of -50~150Mpa.

[0008] As can be seen from the above scheme, by optimizing both the composition and the tube-making process of the round billet used for tube making, a tube billet with excellent machinability and meeting the performance requirements of bearing cages in the wind power field can be obtained. In terms of composition, the aforementioned round billet for tube making is a low-carbon aluminum-killed steel material. Its low carbon content gives the material excellent toughness, ductility, and relatively low strength, making it suitable for machining. It also contains a certain amount of manganese and silicon as solid solution strengthening elements, which can improve the material's strength while ensuring a certain level of toughness, allowing the material to better adapt to heat treatment and machining, while meeting the performance requirements of bearing cages in the wind power field. Furthermore, the content of phosphorus and sulfur, harmful elements that are detrimental to machinability, in the round billet for tube making is strictly limited, while aluminum can improve the material's strength and toughness through grain refinement strengthening, enabling the material to meet the performance requirements of bearing cages.

[0009] In terms of tube manufacturing processes, a combination of hot rolling, heat treatment, cold drawing, cold rolling, and annealing can produce seamless tube blanks with high strength and toughness while maintaining good dimensional accuracy. These tube blanks can meet the machining performance requirements of bearing cages in the wind power industry. The aforementioned tube manufacturing process can also eliminate most of the residual stress in the tube blank material, ensuring that the bearing cages, as the final machined product, meet the corresponding performance and durability requirements.

[0010] A further option is to perform piercing at 1230~1280℃, continuous rolling at 1000~1200℃, and sizing at 900~1050℃ in step S10.

[0011] A further option is that in step S20, normalizing is performed at 800~930℃ for 10~30 minutes. The tempering process includes a first stage and a second stage. In the first stage, the seamless tube is held at 800~930℃ for 20~40 minutes and then quenched. In the second stage, the seamless tube is tempered at 500~650℃ for 20~40 minutes. The grain size of the mother tube is not lower than level 5.

[0012] A further option is to perform cold drawing or cold rolling under a pressure of 100 to 600 tons in step S30.

[0013] A further option is to perform annealing at 450~650℃ for more than 30 minutes in step S40.

[0014] As can be seen from the above schemes, the above-mentioned piercing, continuous rolling, and sizing temperature parameter ranges help to obtain seamless tubes with the required shape and size. The above-mentioned normalizing, quenching, and tempering temperature parameter ranges help to obtain fine-grained mother tubes, giving them good strength and toughness. The above-mentioned pressure parameter ranges are suitable for the cold drawing or cold rolling of the mother tube to meet the dimensional accuracy requirements of the tube blank. The above-mentioned annealing treatment can effectively eliminate cold drawing or cold rolling stress, restore the plasticity and toughness of the material, and also play a role in stabilizing the crystal phase structure and tube blank size. The mother tube obtained by the above-mentioned normalizing treatment is mainly composed of ferrite and pearlite structures, with the proportion of pearlite structure being less than 20%. The mother tube obtained by the above-mentioned quenching and tempering treatment is mainly composed of ferrite and bainite structures, with the proportion of ferrite being more than 60% and the proportion of bainite being less than 40%.

[0015] A further option is that the round billet used for tube making also includes trace alloying elements, which are selected from at least one of Nb, V, Ti, Cr, and Ni.

[0016] As can be seen from the above schemes, niobium, vanadium, and titanium are all microalloying elements. Introducing niobium into round billets for pipe manufacturing can refine the grains during rolling, ensuring the material's toughness. Introducing vanadium into round billets for pipe manufacturing can achieve precipitation strengthening after phase transformation, improving the material's strength. Titanium plays a similar role to niobium and vanadium. Introducing two or more microalloying elements simultaneously can achieve composite microalloying, such as V-Nb and V-Nb-Ti composite microalloying. Chromium can form a chromium oxide passivation film on the material surface to improve the material's corrosion resistance. Introducing nickel can stabilize the austenitic structure in steel, thereby improving the material's low-temperature toughness and also contributing to improved corrosion resistance.

[0017] To achieve the second objective mentioned above, the present invention provides a bearing cage blank, which is characterized in that it is prepared by the aforementioned method for manufacturing bearing cage blanks, and the bearing cage blank has a yield strength of 150~500MPa, a tensile strength of 250~900MPa, an elongation of 15~45%, and a Vickers hardness HV10 of 80~300.

[0018] As can be seen from the above scheme, the bearing cage blank produced by the aforementioned method can roughly meet the above requirements for yield strength, tensile strength, elongation and Vickers hardness HV10, and can adapt to the machining process of bearing cages in the wind power field. For example, it can avoid defects such as cracking and missing material in the window punching process.

[0019] A further proposed solution is to ensure that the outer and inner diameter deviations of the bearing cage tube blank are ≤0.5mm and the roundness deviation is ≤0.5mm.

[0020] As can be seen from the above scheme, in order to ensure the shape and dimensional accuracy of the bearing cage, the inner and outer diameter deviations and roundness deviations of the corresponding tube blanks need to be controlled within the above range.

[0021] To achieve the third objective mentioned above, the present invention provides a method for manufacturing a bearing cage, which is characterized by including the following manufacturing steps: shaping the aforementioned bearing cage blank, punching the window hole, beveling the window hole beam, precision turning, and surface treatment.

[0022] As can be seen from the above scheme, compared with the conventional process of making bearing cages from sheet metal, the above manufacturing method can eliminate the processing steps of making round blanks, making cylindrical blanks, punching positioning holes, and machining the bottom, thereby simplifying the manufacturing process and improving production efficiency. The material utilization rate can be significantly improved from about 10-30% of the conventional process. Moreover, each of the above manufacturing steps can basically follow the corresponding conventional process without major adjustments, which helps to reduce the difficulty of process design and verification.

[0023] To achieve the fourth objective mentioned above, the present invention provides a bearing cage, which is characterized in that, when manufactured by the aforementioned bearing cage manufacturing method, the difference in Vickers hardness HV10 at various locations on the bearing cage is within 30.

[0024] As can be seen from the above scheme, since the tube blank itself already has good strength, toughness and material consistency, the bearing cage made by the aforementioned process has good mechanical properties, and the difference in Vickers hardness HV10 in various parts of the product can be controlled within 30.

[0025] This invention optimizes both the composition of the billet and the tube-making process to obtain a tube blank with excellent machinability that meets the performance requirements of bearing cages in the wind power field. Compared with conventional processes, the production of wind power bearing cages using this tube blank can reduce the number of manufacturing steps, thereby simplifying the manufacturing process and improving production efficiency. The resulting bearing cage has good mechanical properties and meets the durability requirements of the wind power field. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the bearing cage structure prepared in Example 1.

[0027] Figure 2 This is a diagram illustrating the missing material defect in the window punching process of Comparative Example 1. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention are clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0029] Wind power equipment requires ultra-long-term maintenance-free operation, which places extremely high demands on the performance and dimensional accuracy of bearing cages, a critical component. Existing bearing cage manufacturing processes typically use sheet metal to create cylindrical blanks to meet machining requirements. While using steel pipes as blanks to manufacture cylindrical bearing cages theoretically eliminates many processes and has promising application prospects, existing pipe materials cannot simultaneously meet both the relevant machining requirements and the performance and durability requirements of bearing cages in the wind power sector. This invention provides a bearing cage blank adapted to relevant machining processes and its manufacturing method. Furthermore, this invention provides a bearing cage manufactured using the aforementioned bearing cage blank and its related manufacturing method.

[0030] Example 1 The method for manufacturing the bearing cage blank involved in this embodiment includes the following steps: Step S10: The round billet for tube making is subjected to piercing, continuous rolling, sizing and cooling to obtain a seamless tube; The round billet for pipe making includes Fe, C, Mn, Si, P, S, Al, Nb, and V elements. By weight percentage, the round billet contains 0.085% C, 0.43% Mn, 0.25% Si, 0.012% P, 0.008% S, 0.021% Al, 0.02% Nb, and 0.02% V. The piercing process is carried out at 1230℃, the continuous rolling process is carried out at 1200℃, the sizing process is carried out at 910℃, and the cooling process is carried out by air cooling. Step S20: The seamless tube is normalized at 920℃ for 20 minutes to obtain a mother tube with a grain size of grade 5 or higher; Step S30: The mother tube is cold-drawn under a pressure of 100~600 tons to obtain a cold-formed tube; Step S40: Anneal the cold-formed tube at 500°C for more than 30 minutes to obtain the bearing cage tube blank.

[0031] The method for manufacturing the bearing cage involved in this embodiment includes: The aforementioned bearing cage blank is subjected to a series of processes including segmented blanking, flattening, inner and outer surface machining, shaping, window punching, window beam beveling, precision turning, and surface treatment.

[0032] See Figure 1 The above-mentioned segmented blanking process refers to cutting the aforementioned bearing cage tube blank into tube sections 1 suitable for subsequent machining, with sufficient machining allowance retained for tube sections 1; the above-mentioned flattening process refers to the machining process of flattening and deburring both ends of tube section 1; the above-mentioned internal and external surface machining process refers to the process of finishing the internal and external surfaces of tube section 1 to meet the internal and external diameter requirements; the above-mentioned window hole punching refers to the machining step of punching and cutting off the tube wall portion of tube section 1 to form window holes 2; the above-mentioned window hole beam slope refers to the machining step of punching and shaping the window hole beam 3 structure between window holes 2; the above-mentioned precision turning refers to the deburring process of the workpiece by means of shot peening, etc.; the above-mentioned surface treatment refers to the step of phosphating after cleaning the surface of the workpiece.

[0033] Example 2 The method for manufacturing the bearing cage blank in this embodiment is largely the same as that in Embodiment 1, except that: The round billet used in step S10 contains, by weight percentage, 0.075% C, 0.38% Mn, 0.25% Si, 0.011% P, 0.007% S, 0.025% Al, 0.025% Nb, and 0.02% V. The piercing process is performed at 1240℃, the continuous rolling process at 1000℃, and the sizing process at 950℃. Step S20 involves quenching and tempering the seamless tube. Specifically, the seamless tube is heated to 930℃ and held for 30 minutes, then quenched in clean water, followed by tempering at 500℃ for 20 minutes to obtain a mother tube with a grain size of grade 5 or higher. Step S30 involves cold rolling the mother tube under a pressure of 100-600 tons to obtain a cold-formed tube. Step S40 involves annealing the cold-formed tube at 600℃ for at least 30 minutes.

[0034] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0035] Example 3 The method for manufacturing the bearing cage blank in this embodiment is largely the same as that in Embodiment 1, except that: The round billet used in step S10 contains, by weight percentage, 0.11% C, 1.25% Mn, 0.3% Si, 0.013% P, 0.008% S, 0.025% Al, 0.02% Nb, and 0.037% V. The piercing process is carried out at 1250°C, the continuous rolling process is carried out at 1180°C, and the sizing process is carried out at 1000°C. Step S20 performs normalizing treatment on the seamless tube at 800°C for 10 minutes. Step S40 performs annealing treatment on the cold-formed tube at 450°C for more than 30 minutes.

[0036] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0037] Example 4 The method for manufacturing the bearing cage blank in this embodiment is largely the same as that in Embodiment 1, except that: The round billet used in step S10 contains, by weight percentage, 0.038% C, 0.69% Mn, 0.6% Si, 0.016% P, 0.011% S, 0.033% Al, 0.022% Ti, and 0.02% Cr. The piercing process is performed at 1280°C, the continuous rolling process at 1090°C, and the sizing process at 1050°C. Step S20 involves normalizing the seamless tube at 850°C for 30 minutes. Step S30 involves cold rolling the mother tube under a pressure of 100-600 tons to obtain a cold-formed tube. Step S40 involves annealing the cold-formed tube at 650°C for at least 30 minutes.

[0038] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0039] Example 5 The method for manufacturing the bearing cage blank in this embodiment is largely the same as that in Embodiment 1, except that: The round billet used in step S10 contains, by weight percentage, 0.16% C, 1.45% Mn, 0.85% Si, 0.02% P, 0.018% S, 0.028% Al, 0.033% V, 0.02% Ti, and 0.024% Ni. The piercing process is performed at 1260℃, the continuous rolling process at 1140℃, and the sizing process at 900℃. Step S20 involves quenching and tempering the seamless tube. Specifically, the seamless tube is heated to 900℃ and held for 40 minutes, then quenched in clean water, followed by tempering at 630℃ for 40 minutes to obtain a mother tube with a grain size of grade 5 or higher. Step S40 involves annealing the cold-formed tube at 550℃ for at least 30 minutes.

[0040] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0041] Comparative Example 1 The method for manufacturing the bearing cage blank in this comparative example is largely the same as that in Example 1, except that: The round billet used in step S10 contains, by weight percentage, 0.3% C, 1.52% Mn, 0.25% Si, 0.014% P, 0.009% S, 0.029% Al, 0.02% Nb, and 0.02% V. The piercing process is carried out at 1280°C, the continuous rolling process is carried out at 1100°C, and the sizing process is carried out at 1050°C. Step S20 involves normalizing the seamless tube at 920°C for 30 minutes. Step S40 involves annealing the cold-formed tube at 500°C for more than 30 minutes.

[0042] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0043] Comparative Example 2 The method for manufacturing the bearing cage blank in this comparative example is largely the same as that in Example 1, except that: The round billet used in step S10 contains, by weight percentage, 0.1% C, 1.25% Mn, 0.25% Si, 0.012% P, 0.0012% S, 0.025% Al, 0.022% Nb, and 0.03% V. The piercing process is carried out at 1250°C, the continuous rolling process is carried out at 1150°C, and the sizing process is carried out at 1020°C. In step S20, the seamless tube is normalized at 920°C for 30 minutes. After completing step S30, the cold-formed tube is not annealed, i.e., step S40 is not performed.

[0044] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0045] Comparative Example 3 The method for manufacturing the bearing cage blank in this comparative example is largely the same as that in Example 1, except that: The round billet used in step S10 contains, by weight percentage, 0.078% C, 0.35% Mn, 0.25% Si, 0.015% P, 0.01% S, 0.028% Al, 0.02% Nb, and 0.032% V. The piercing process is carried out at 1240°C, the continuous rolling process is carried out at 1140°C, and the sizing process is carried out at 1010°C. After completing step S10, the seamless tube is not normalized or quenched and tempered, i.e., step S20 is skipped. After completing step S30, the cold-formed tube is not annealed, i.e., step S40 is not performed.

[0046] The method for manufacturing the bearing cage in this embodiment is the same as that in Embodiment 1.

[0047] The yield strength, tensile strength, elongation, Vickers hardness HV10, and residual stress of the bearing cage blanks prepared in the above embodiments and comparative examples were tested. The roundness of the blanks and bearing cages was measured and the difference was calculated. The appearance quality of the workpieces after the window holes were stamped was checked. The test results of the above items are shown in Table 1. The above test items were tested in accordance with the relevant standards of ISO / TR10400 and GB / T 228.1-2010 (Part 1: Test methods at room temperature).

[0048] Table 1: Mechanical property test results of the examples and comparative examples As shown in Table 1, the yield strength of the bearing cage blanks in the example group was all below 500 MPa, the elongation was significantly higher than that in the comparative example group, and the residual stress was all within the range of -50 to 150 MPa. Furthermore, the appearance quality of the workpieces after the window punching process was all qualified, indicating that the bearing cage blanks produced by this invention have good machinability and meet the performance and durability requirements of bearing cages in the wind power field. In Comparative Example 1, due to the excessively high C content in the blank, the material's strength (e.g., tensile strength) was too high and its toughness was poor, resulting in obvious defects such as missing material in the workpiece during the window punching process (see...). Figure 2Comparative Examples 2 and 3 skipped the annealing process after cold drawing, and Comparative Example 3 also skipped the normalizing or quenching and tempering process after hot rolling. As a result, the residual stress of the bearing cage blanks made in Comparative Examples 2 and 3 exceeded 150 MPa. Furthermore, the roundness change of the blanks after machining was larger and significantly greater than that of the example group. This was not conducive to the dimensional accuracy control of the workpieces. The bearing cages made from these blanks were difficult to adapt to the operating conditions of wind power equipment and did not meet the durability requirements of the relevant components.

[0049] Furthermore, by detecting and comparing the Vickers hardness HV10 at multiple specified points on the bearing cage corresponding to each embodiment, it was determined that the difference between the maximum and minimum detected values ​​of the Vickers hardness HV10 at each point on the bearing cage corresponding to each embodiment is within 30.

[0050] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0051] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of making a bearing retainer tube blank, characterized by, The method comprises the following steps: Step S10: performing piercing, continuous rolling, sizing and cooling treatment on a round blank for pipe making to obtain a seamless pipe, the round blank for pipe making comprising Fe, C, Mn, Si, P, S and Al elements, the content of the C element in the round blank for pipe making being 0.02-0.2% by weight, the content of the Mn element being 0.1-1.8% by weight, the content of the Si element being ≤1% by weight, the content of the P element being ≤0.03% by weight, the content of the S element being ≤0.03% by weight, and the content of the Al element being ≤0.04% by weight; Step S20: performing normalizing or quenching and tempering treatment on the seamless pipe to obtain a mother pipe; Step S30: performing cold drawing or cold rolling treatment on the mother pipe to obtain a cold-formed pipe; Step S40: performing annealing treatment on the cold-formed pipe to obtain a bearing retainer pipe blank with a residual stress value of-50-150 MPa.

2. The method according to claim 1, wherein: the piercing treatment is performed at 1230-1280℃, the continuous rolling treatment is performed at 1000-1200℃, and the sizing treatment is performed at 900-1050℃ in step S10.

3. The method according to claim 1, wherein: the normalizing treatment is performed at 800-930℃ with a holding time of 10-30 min in step S20, the quenching and tempering treatment comprises a first stage and a second stage, the first stage is performed after the seamless pipe is held at 800-930℃ for 20-40 min, the second stage is performed by tempering the seamless pipe at 500-650℃ with a holding time of 20-40 min, and the grain size of the mother pipe is not less than 5 levels.

4. The method according to claim 1, wherein: the cold drawing or cold rolling treatment is performed under a pressure of 100-600 tons in step S30.

5. The method according to claim 1, wherein: the annealing treatment is performed at 450-650℃ for more than 30 min in step S40.

6. The method according to claim 1, wherein: the round blank for pipe making further comprises trace alloying elements selected from at least one of Nb, V, Ti, Cr and Ni.

7. A bearing retainer pipe blank, wherein: the bearing retainer pipe blank is obtained by the method according to any one of claims 1-6, the yield strength of the bearing retainer pipe blank is 150-500 MPa, the tensile strength is 250-900 MPa, the elongation is 15-45%, and the Vickers hardness HV10 is 80-300.

8. The bearing retainer pipe blank according to claim 7, wherein: the outer diameter and inner diameter deviation of the bearing retainer pipe blank is ≤0.5 mm, and the roundness deviation is ≤0.5 mm.

9. A method for manufacturing a bearing retainer, wherein: The manufacturing steps include shaping, window punching, window beam beveling, finish machining and surface treatment of the bearing retainer tube blank of claim 7 or 8.

10. A bearing cage, characterized in that: The bearing cage is made by the manufacturing method of claim 9, and the Vickers hardness HV10 difference of the bearing cage is within 30.

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