Forming process of super-large solid copper retainer

Abstract

The invention provides a forming process of an ultra-large solid copper retainer, which adopts a three-dimensional centrifugal casting integrated forming process and comprises the following steps: step 1, on the basis that a centrifugal mold and a mold cover are connected by adopting a bolt, the centrifugal mold and the mold cover are connected by adopting a self-locking pin structure; secondly, a third-stage funnel is placed along a reserved vacancy of a protective top cover of the vertical centrifugal machine, penetrates through a center hole of a mold cover and then enters an inner cavity of the centrifugal mold; according to the ultra-large specification solid copper retainer forming process, through the arrangement of integral forming, mold cover fastening connection mode optimization, three-stage funnel flow guide device design, temperature correction coefficient introduction, water outlet position solidification and the like, the structural integrity of a copper retainer, the safety of the casting process and the stability of the casting quality are remarkably improved; the defects of a traditional sectional forming process are overcome, the service life of the copper retainer is greatly prolonged, the mechanical performance of the copper retainer is greatly improved, and the copper retainer has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of cage processing technology, and particularly relates to a forming process for an extra-large-sized solid copper cage. Background Art

[0002] A copper cage is a mechanical part made of copper alloy, used to fix the bearing rolling elements in a mechanical device, playing a role in support and retention. The copper cage has characteristics such as high strength, high hardness, and high toughness, and can withstand the high loads and high speeds generated during the operation of the machine equipment, ensuring the normal operation of the equipment.

[0003] According to different processing methods, it can be divided into forged copper cages, cast copper cages, drawn copper cages, profile processed and formed cages, etc. Forged copper cages have a relatively high density, and also relatively high strength and hardness, and are commonly used in bearings with high strength and high-speed rotation; cast copper cages (ordinary casting) have a lower cost and a simple manufacturing process, but have a lower density, and relatively lower strength and hardness, and are usually used in medium and low-speed bearings; drawn copper cages have high strength and hardness, and the copper material structure is more dense after a special drawing process, and can be used in high-speed and high-load bearings; profile processed and formed cages are made by machining suitable bars and tubes for the cage, with a higher cost, and are suitable for small-batch and small-sized bearings.

[0004] Currently, for extra-large-sized solid copper cages, a segmented forming process is mainly adopted, and the copper cage is segmented and formed by forging or casting methods. However, this manufacturing process has problems such as insufficient machining accuracy, unstable cage structure, poor retention effect, and serious wear and failure. Summary of the Invention

[0005] The present invention provides a forming process for an extra-large-sized solid copper cage. First, integral forming is carried out to ensure the integrity of the copper cage, solving the problems of inconsistent size control during the processing, unstable structure, poor retention effect, and serious wear during use; secondly, during the centrifugal forming process, impurities and gas components in the copper alloy molten liquid are effectively removed, improving the structural purity and density of the copper cage, and significantly improving various mechanical properties of the copper cage; finally, the automatic water cooling control system uses the cooling residual heat of the copper alloy melt to perform on-line heat treatment, improving the hardness of the solid copper cage, further enhancing the hardness of the solid copper cage, and improving wear resistance.

[0006] The technical solution adopted by the present invention is: a forming process for an extra-large-sized solid copper cage, which adopts a three-dimensional centrifugal casting integral forming process, including the following steps: Step 1: On the basis of connecting the centrifugal mold and the mold cover with bolts, then connect them by means of a self-locking pin structure; Step 2: Place the three-stage funnel in the reserved space of the protective top cover of the vertical centrifuge, pass through the central hole of the mold cover and enter the inner cavity of the centrifugal mold, so that the center point of the vertical direction of the water outlet of the three-stage funnel and the axial height center of the centrifugal mold are in the same plane, and make the horizontal center line of the water outlet of the three-stage funnel form a 60° angle with the tangent line at the copper water receiving point of the centrifugal mold; Step 3: Start the vertical centrifuge, the centrifugal mold and the mold cover rotate synchronously, correctly set the rotation speed of the centrifuge, transfer the qualified copper liquid in terms of composition and temperature to the upper port of the three-stage funnel through the transfer ladle, and pour the copper liquid into the three-stage funnel following the principle of "slow-fast-slow", and guide it into the centrifugal mold; Step 4: Carry out on-line heat treatment and cooling of the centrifugal mold through the automatic water cooling equipment, and finally form the cage.

[0007] The self-locking pin structure includes self-locking pin holes arranged on the edge of the centrifugal mold and opened in the radial direction, and self-locking pins that can be inserted into the self-locking pin holes. The self-locking pins are in mutual contact with the upper surface of the mold cover, and the outer diameter size of the self-locking pins gradually decreases from the center of the centrifugal mold to the outside.

[0008] The self-locking pin holes are evenly distributed around the center of the centrifugal mold.

[0009] The three-stage funnel includes a material receiving area located at the top and in the shape of a funnel. The lower end of the material receiving area is connected to a straight-through section, and the lower end of the straight-through section is connected to a material discharging area. During the centrifugal casting process, the material discharging area is located in the cavity formed by the centrifugal mold and the mold cover.

[0010] The outer diameter size of the cage is 2.4m - 6m.

[0011] The calculation of the rotation speed of the vertical centrifuge adopts the modified Konstantinov formula:

[0012] Where: n is the rotation speed of the centrifuge (r / min), β is the correction coefficient, k is the temperature correction coefficient, γ is the specific weight of the alloy (N / m³), R is the inner radius of the centrifugal mold (m).

[0013] The value range of the correction coefficient β is 1.0 - 1.5, and the value range of the temperature correction coefficient k is 0.95 - 1.1.

[0014] The pouring temperature range of the copper liquid is 1000℃ - 1420℃.

[0015] After the cage is formed, observe whether there are defects on the appearance of the cage, and detect whether there are segregation, cracks and slag inclusions inside the cage through an ultrasonic flaw detector.

[0016] The beneficial effects of the present invention are as follows: Through settings such as integral molding, optimization of the fastening connection method of the mold cover, design of the three-stage funnel diversion device, introduction of the temperature correction coefficient, and solidification of the water outlet position, the super-large specification solid copper cage forming process of the present invention significantly improves the structural integrity of the copper cage, the safety during the casting process, and the stability of the casting quality. It not only solves the defects of the traditional segmented forming process, but also greatly improves the service life and mechanical properties of the copper cage, and has broad application prospects. Brief Description of the Drawings

[0017] Figure 1 It is a three-dimensional view of the present invention with the mold cover hidden; Figure 2 It is a side view of the present invention with the mold cover hidden; Figure 3 It is a top view of the present invention with the mold cover hidden; Figure 4 It is a connection structure diagram of the centrifugal mold and the mold cover of the present invention.

[0018] Wherein: 1. Centrifugal mold; 101. Self-locking pin hole; 102. Reinforcing rib; 2. Three-stage funnel; 201. Material receiving area; 202. Straight-through section; 203. Discharge area; 3. Mold cover; 301. Bolt mounting hole; 4. Self-locking pin. Detailed Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] As shown in the figure, a super-large specification solid copper cage forming process, which adopts a three-dimensional centrifugal casting integral forming process, and the outer diameter size of the cage is 2.4m - 6m. This process includes the following steps: Step 1: On the basis of connecting the centrifugal mold 1 and the mold cover 3 by bolts, connect them by means of a self-locking pin structure; Among them, a plurality of bolt mounting holes 301 evenly distributed around the center of the mold cover 3 are formed on the surface of the mold cover 3, and threaded holes corresponding to the bolt mounting holes 301 are formed on the centrifugal mold 1. The mold cover 3 and the centrifugal mold 1 are first connected by bolts. The self-locking pin structure includes a self-locking pin hole 101 formed on the edge of the centrifugal mold 1 and opened in the radial direction, and a self-locking pin 4 that can be inserted into the self-locking pin hole 101. The self-locking pin holes 101 are evenly distributed around the center of the centrifugal mold 1. Among them, evenly distributed reinforcing ribs 102 are arranged around the centrifugal mold 1, and the reinforcing ribs 102 extend upward to the centrifugal mold 1. The self-locking pin holes 101 are formed on the reinforcing ribs 102. The self-locking pin 4 abuts against the upper surface of the mold cover 3. The outer diameter dimension of the self-locking pin 4 gradually decreases from the center of the centrifugal mold 1 to the outside, that is, the self-locking pin 4 has a conical structure. With such a setting, during the operation of the centrifugal mold 1, the self-locking pin 4 can move outward under the action of centrifugal force, thereby improving the connection stability between the mold cover 3 and the centrifugal mold 1, and avoiding problems such as loosening under the action of centrifugal force, mold cover 3 falling off or copper liquid leakage caused by the traditional simple bolt fastening method, greatly improving the safety during the casting process.

[0021] Step 2: Place the three-stage funnel 2 in the reserved space of the vertical centrifuge protective top cover, and pass through the central hole of the mold cover 3 and then enter the inner cavity of the centrifugal mold 1, so that the center point of the vertical direction of the water outlet of the three-stage funnel 2 and the axial height center of the centrifugal mold 1 are in the same plane (such as Figure 2 the plane α shown), with such a setting, it is ensured that the copper liquid flows evenly from the center position of the mold, avoiding the problem of uneven distribution of the copper liquid in the mold. This design can effectively prevent the copper liquid from generating uneven flow or local accumulation in the mold, ensure that the copper liquid is evenly distributed under the action of centrifugal force, form a dense and uniform casting structure, and by controlling the flow direction and speed of the copper liquid, the generation of casting defects such as pores, slag inclusions, and cracks can be reduced, improving the internal quality and mechanical properties of the copper cage.

[0022] And make the horizontal center line of the water outlet of the three-stage funnel 2 form a 60° angle with the tangent line at the copper water receiving point of the centrifugal mold 1 (such as Figure 3 shown), with such a setting, the copper liquid can enter the inner cavity of the mold at the best angle, reducing the impact force and splashing phenomenon of the copper liquid when entering the mold. At the same time, the 60° angle can guide the copper liquid to flow smoothly along the inner wall of the mold, avoiding the generation of eddy currents or turbulence, and ensuring the uniform distribution of the copper liquid in the mold. By reducing splashing and eddy currents, the waste of copper liquid can be effectively reduced, the utilization rate of copper liquid can be improved, and the production cost can be reduced.

[0023] Specifically, the three-stage funnel 2 includes a material receiving area 201 located at the top and in the shape of a funnel. The lower end of the material receiving area 201 is connected to a straight-through section 202, and the lower end of the straight-through section 202 is connected to a material discharging area 203. During the centrifugal casting process, the material discharging area 203 is located within the cavity formed by the centrifugal mold 1 and the mold cover 3. Among them, the material receiving area 201 mainly functions to receive the copper alloy melt, the straight-through section 202 mainly controls the height difference between the centrifuge protective cover and the centrifugal mold 1, and the material discharging area 203 mainly functions to guide the copper alloy melt. With such a setting, not only is the guiding effect of the copper alloy melt good, but it is also more convenient to clean and repair the funnel after casting is completed.

[0024] Step 3: Start the vertical centrifuge. The centrifugal mold 1 and the mold cover 3 rotate synchronously. Correctly set the rotation speed of the centrifuge. Transfer the qualified copper liquid in terms of composition and temperature to the upper port of the three-stage funnel 2 through the transfer ladle. Pour the copper liquid into the three-stage funnel 2 following the principle of "slow - fast - slow", and guide it into the centrifugal mold 1. Specifically, the rotation speed of the vertical centrifuge is calculated using the modified Konstantinov formula:

[0025] where: n is the rotation speed of the centrifuge (r / min), β is the correction coefficient, k is the temperature correction coefficient, γ is the specific weight of the alloy (N / m³), R is the inner radius of the centrifugal mold (m).

[0026] The value range of the correction coefficient β is 1.0 - 1.5, the value range of the temperature correction coefficient k is 0.95 - 1.1, and the pouring temperature range of the copper liquid is 1000°C - 1420°C.

[0027] Specifically, the correction coefficient of the Konstantinov formula and the temperature correction coefficient follow the following table: Table 1: Correction Coefficient of the Konstantinov Formula Table 2: Temperature Correction Coefficient

[0028] With such settings, the accuracy of rotational speed calculation can be improved and the stability of casting quality can be enhanced. The temperature of the copper alloy solution directly affects its fluidity and solidification rate. The traditional rotational speed calculation formula for centrifuges does not consider the temperature factor, resulting in inaccurate rotational speed setting and affecting casting quality. In this embodiment, by introducing a temperature correction coefficient k and modifying the Konstantinov formula, the rotational speed of the centrifuge can be accurately calculated according to the actual temperature of the copper alloy solution, ensuring the uniformity of the copper liquid distribution in the mold and the consistency of the solidification rate, thus improving the casting quality. By precisely controlling the rotational speed of the centrifuge, problems such as uneven copper liquid distribution and inconsistent solidification rate caused by improper rotational speed can be effectively avoided, ensuring that the cast copper cage has a dense internal structure without defects such as pores and slag inclusions.

[0029] Step Four: Conduct on-line heat treatment and cooling on the centrifugal mold 1 through an automatic water cooling device, and finally form the cage. Among them, the automatic water cooling device and the heat treatment and cooling method for the product belong to conventional technologies in the prior art and will not be elaborated here. After the cage is formed, observe whether there are defects on the appearance of the cage, specifically observe whether there are defects such as ash grooves, slag inclusions, lack of material, cracks, and incomplete structure on its appearance, and use an ultrasonic flaw detector to detect whether there are defects such as segregation, cracks, and slag inclusions inside the cage.

[0030] The following are the specific forming processes for two cages with different diameters.

[0031] 1. Manufacture an aluminum bronze cage with a diameter of 2.4 meters. The casting blank weight of a single cage is 1560 kg. Design the mold according to the cage size requirements, and tightly connect the mold cover 3 through bolts and self-locking pins; the pouring temperature of the copper alloy is 1320 °C, and calculate the rotational speed of the centrifuge to be 270 r / min according to the modified Konstantinov formula (see Table 3 for details); pour the copper alloy solution into the centrifugal mold 1 through a three-stage funnel 2 following the principle of "slow - fast - slow". During the pouring process, the copper alloy solution flows smoothly without splashing or spilling; turn on the automatic water cooling device until the centrifuge stops rotating. Observe the formed aluminum bronze cage, and there are no defects such as ash grooves, slag inclusions, lack of material, cracks, and incomplete structure on its appearance. Through ultrasonic flaw detection, the internal echo of the cage is stable, and there are no defects such as segregation, cracks, and slag inclusions.

[0032] Table 3: Calculation of the Rotational Speed of the Aluminum Bronze Casting Centrifuge

[0033] 2. Manufacture a leaded brass cage with a diameter of 3.1 meters. The weight of the single-piece casting blank of the cage is 1890 kg. Design the mold according to the size requirements of the cage, fasten the mold cover 3 with bolts and self-locking pins. The pouring temperature of the copper alloy is 1060 °C. Calculate the centrifuge speed at 250 revolutions / min according to the corrected Konstantinov formula (see Table 4 for details). Pour the copper alloy solution into the centrifugal mold 1 through the three-stage funnel 2 following the principle of "slow-fast-slow". During the pouring process, the copper alloy solution flows smoothly without splashing or spilling. Turn on the automatic water cooling device until the centrifuge stops rotating. Observe the formed leaded brass cage. There are no defects such as ash grooves, slag inclusions, lack of material, cracks, and incomplete structure on the appearance. After detecting with an ultrasonic flaw detector, the internal echo of the cage is stable, without defects such as segregation, cracks, and slag inclusions.

[0034] Table 4: Calculation of the centrifuge speed for leaded brass casting

[0035] Through the above embodiments, it can be seen that the forming process of this ultra-large-sized solid copper cage is stable and reliable during the implementation process, the product quality is stable, effectively solving the problem of integral forming of ultra-large-sized solid copper cages, and thoroughly solving problems such as insufficient machining accuracy in subsequent processes, unstable structure during use, poor holding effect, and serious wear failure.

[0036] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for forming an oversized solid copper cage, characterized in that: The process adopts a three-dimensional centrifugal casting one-piece molding process, including the following steps: Step 1: Connect the centrifugal mold and the mold cover by bolts and then connect them by a self-locking pin structure; Step 2: Place the three-stage funnel along the reserved space of the vertical centrifuge protective top cover, and enter the inner cavity of the centrifugal mold after passing through the center hole of the mold cover, so that the vertical center point of the three-stage funnel outlet and the axial height center of the centrifugal mold are in the same plane, and the horizontal center line of the three-stage funnel outlet and the tangent line at the copper water point of the centrifugal mold are at an angle of 60°; Step 3: Start the vertical centrifuge, rotate the centrifugal mold and the mold cover synchronously, set the centrifuge speed correctly, transfer the copper liquid with qualified composition and temperature to the upper port of the three-stage funnel through the transfer bag, pour the copper liquid into the three-stage funnel according to the principle of "slow-fast-slow", and guide it into the centrifugal mold; Step 4: Perform online heat treatment and cooling on the centrifugal mold through automatic water cooling equipment to finally form the cage.

2. The process for forming an oversized solid copper cage according to claim 1, characterized in that: The self-locking pin structure includes a self-locking pin hole arranged on the edge of the centrifugal mold and opened in the radial direction, and a self-locking pin that can be inserted into the self-locking pin hole. The self-locking pin abuts against the upper surface of the mold cover, and the outer diameter of the self-locking pin gradually decreases from the center of the centrifugal mold to the outside.

3. The process for forming an oversized solid copper cage according to claim 2, characterized in that: The self-locking pin holes are evenly distributed around the center of the centrifugal die.

4. The process for forming an oversized solid copper cage according to claim 1, characterized in that: The three-stage funnel includes a funnel-shaped receiving area located at the top, the lower end of the receiving area is connected to a straight section, and the lower end of the straight section is connected to a discharge area. During the centrifugal casting process, the discharge area is located in the cavity formed by the centrifugal mold and the mold cover.

5. The process for forming an oversized solid copper cage according to claim 1, characterized in that: The outer diameter of the cage is 2.4m-6m.

6. The process for forming an oversized solid copper cage according to claim 1, characterized in that: The calculation of the vertical centrifuge speed uses the modified Konstantinov formula:

7. Among them: n is the centrifuge speed (r / min), β is the correction coefficient, k is the temperature correction coefficient, γ is the density of the alloy (N / m³), R is the inner radius of the centrifugal mold (m).

8. The process for forming an oversized solid copper cage according to claim 6, characterized in that: The correction coefficient β ranges from 1.0 to 1.5, and the temperature correction coefficient k ranges from 0.95 to 1.

1.

9. The process for forming an oversized solid copper cage according to claim 6, characterized in that: The pouring temperature range of the copper liquid is 1000℃-1420℃.

10. The process for forming an oversized solid copper cage according to claim 1, characterized in that: After the cage is formed, observe whether there are defects in the appearance of the cage, and use an ultrasonic flaw detector to detect whether there are segregation, cracks, and slag inclusions inside the cage.

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