A mold structure and process method for centrifugal aluminum casting of electric motor rotor
By adopting centrifugal cast aluminum mold structure and process methods in the aluminum end ring of the motor rotor, and using high-temperature flue gas heating and centrifugal cooling, the problems of poor quality of aluminum end rings and bulky equipment in the existing technology are solved, and high density is achieved. The production of low porosity aluminum end rings simplifies process flow and equipment, and improves efficiency and quality.
Patent Information
- Application Number
- CN202411304660.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2044-09-19
AI Technical Summary
In the prior art, there are a large number of air holes or shrinkage holes in the end ring of the rotor of the motor, and the vertical centrifugal cast aluminum process equipment is huge, the mold is bulky, the manual operation strength is large, the quality is poor, and it is difficult to meet the high reliability requirements.
The mold structure and process method of centrifugal cast aluminum are adopted for motor rotor. The left cast aluminum mold and the right cast aluminum mold are concentrically inserted on the mandrel. The mold cavity and iron core are heated by high-temperature flue gas, and the aluminum liquid is cooled under the action of centrifugal force. The rotor end ring adopts horizontal shaft rotation and roller drive, simplifying equipment and operation and reducing labor intensity.
It improves the density and continuity of the rotor aluminum end ring, reduces porosity, is suitable for complex structures, reduces equipment investment and energy consumption, and improves production efficiency and product quality.
Smart Images
Figure CN118808584B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field related to asynchronous motor rotor manufacturing, and specifically relates to a mold structure and a process method for centrifugal aluminum casting of a motor rotor. Background Art
[0002] Ordinary three-phase or single-phase asynchronous motors do not have high requirements for the filling quality of cast aluminum squirrel cage rotors. Many small and medium-sized motors, especially micro fractional horsepower motors, are mostly produced by die-casting. There are a large number of pores or shrinkage holes in the aluminum bars and end rings, and the porosity (the ratio of pores, shrinkage holes and insufficiently filled space to the theoretical volume) is about 15-20%; for rotors with higher quality requirements, the vertical centrifugal aluminum casting process is currently commonly used. This method not only has large equipment, heavy molds, manual operation, high labor intensity for workers, but also has no quality guarantee. The porosity of the output rotor aluminum end rings and guide bars is about 8-10%, and the rotor is often accompanied by broken bars and thin bars. These defects can only be discovered through destructive experiments, and the detection cost is high. For occasions with high reliability requirements, vertical centrifugal aluminum casting is also difficult to meet the requirements. Therefore, it is necessary to develop a mold structure and process method for centrifugal aluminum casting of motor rotors to solve the above technical problems. Summary of the invention
[0003] In view of the above problems, the present invention provides a mold structure and process method for centrifugal aluminum casting of motor rotors, which are used to solve the technical problems in the prior art that the mold is bulky, manual operation, workers have high labor intensity, and the quality is not guaranteed.
[0004] To achieve the above object, the technical solution adopted by the present invention is:
[0005] A mold structure for centrifugal aluminum casting of a motor rotor, wherein a left aluminum casting mold, an iron core and a right aluminum casting mold are concentrically inserted on a core shaft, and are blocked by a stopper to form a rotating body, which is horizontally placed on a driving device for rotation; the inner cavity of the left aluminum casting mold and the right aluminum casting mold are in the shape of an annular groove, and the end surface has a hole, and the aluminum liquid in the cavity is cooled under the action of centrifugal force to form a rotor end ring. The inner circle of the end ring does not contact the mold wall, and is cooled and formed in the air.
[0006] As a further improvement of the above scheme, a smoke hood is provided on one side of the left cast aluminum mold, and the smoke hood is connected to the burner. An aluminum leakage hole is provided on the end face of the left cast aluminum mold to allow high-temperature smoke generated by combustion to enter the mold cavity, flow through the guide bar and the aluminum inlet hole of the right cast aluminum mold to heat the mold cavity and the iron core.
[0007] As a further improvement of the above scheme, the left cast aluminum mold includes an outer circle, an inner circle and an inner wall of the left mold cavity, and an aluminum leakage hole is arranged on the end face; a mold center hole and a countersunk hole are arranged in the middle of the end face to allow the core shaft to pass through, and the countersunk hole accommodates the core shaft boss; after the core shaft is installed in the left cast aluminum mold, the tail of the core shaft protrudes out of the end face of the left cast aluminum mold; the diameter of the circumscribed circle of the aluminum leakage hole is larger than the diameter of the inner wall of the left mold cavity by millimeters or more.
[0008] As a further improvement of the above scheme, the inner wall of the left mold cavity of the boss in the groove of the left cast aluminum mold is smaller than the distribution circle of the center of the aluminum leakage hole; the right mold is opposite to the left mold and has the same structural characteristics.
[0009] As a further improvement of the above solution, the mouth of the right aluminum casting mold is provided with a bell mouth for entering the aluminum liquid, and a funnel is provided at the side end of the bell mouth.
[0010] As a further improvement of the above solution, the driving devices of the left cast aluminum mold and the right cast aluminum mold are rollers and pressure wheels, and the rollers have flange structures to limit the axial movement of the core mold combination.
[0011] As a further improvement of the above solution, a guide cone is movably provided at the end of the core shaft, and a limit piece is provided at the connection with the guide cone to limit the position of the right cast aluminum mold and maintain a certain prestress on the lamination group of the iron core.
[0012] As a further improvement of the above solution, a cage bar cavity is provided in the rotor core for forming rotor cage bars after the aluminum liquid solidifies after aluminum casting is completed. End rings at both ends of the rotor are formed in the annular grooves of the left aluminum casting mold and the right aluminum casting mold. The inner circle of the end ring does not contact the inner wall of the mold cavity and is cooled and formed in the air.
[0013] A process for centrifugal aluminum casting of a motor rotor comprises the following steps:
[0014] S1, concentrically inserting the left cast aluminum mold, the rotor iron core and the right cast aluminum mold onto the core shaft to obtain an iron core assembly, and performing pre-tightening and re-tightening;
[0015] S2, place the iron core assembly installed in S1 between two sets of horizontal rollers and cover them with a pressure wheel; the iron core assembly rotates horizontally under the drive of the motor;
[0016] S3. The high-temperature flue gas generated by the burner enters the mold cavity and the guide bar cavity in the rotor core from the overflow hole of the left aluminum casting mold, so that the mold cavity and the surface of the guide bar cavity are heated, and a temperature field with uniform circumferential distribution and continuous gradient along the axial direction is naturally formed in the rotor core;
[0017] S4, pour the aluminum liquid from the funnel into the bell mouth of the right aluminum casting mold and inject it into the mold cavity through the hole. When the aluminum liquid overflows from the overflow hole, stop pouring the aluminum liquid;
[0018] S5, stop firing, the rotor core speeds up and keeps rotating at high speed until the aluminum liquid completely solidifies and stops rotating;
[0019] S6. After stopping the machine, use pneumatic, electric or hydraulic tools to remove the mold.
[0020] As a further improvement of the above solution, the assembly formed by the rotor core and the mold during the aluminum casting process rotates horizontally.
[0021] As a further improvement of the above scheme, in S1, each stack of 50 to 100 mm laminations is pre-pressed once, and the pressure between laminations is 2.5 to 3.0 MPa; after the pre-pressing is completed, the limiter is installed and pressed again, and the pressure is 1.8 to 2.0 MPa.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1. The present invention provides a mold structure and a process method for centrifugal aluminum casting of motor rotors. The product quality is better than that of vertical centrifugal aluminum casting and full-automatic die-casting processes, and the porosity is lower than that of products produced by vertical centrifugal aluminum casting processes. The present invention is particularly suitable for rotors with double squirrel cage structures that have complex groove shapes, narrow structures in guide bars, and are relatively difficult to fill. The rotors produced by this process not only have full aluminum bars, good continuity, high density, and good conductivity, but also the iron core does not need to be heated in a preheating furnace in advance, thereby saving energy.
[0024] 2. The horizontal axis centrifugal aluminum casting method of the present invention has simple equipment and mold structures, and the labor intensity of workers is lower than that of vertical centrifugal aluminum casting. The mold can be removed by equipment or powered tools, which greatly reduces the investment cost of the equipment and the labor intensity of workers. At the same time, it is not necessary to preheat the iron core before aluminum casting, which reduces energy consumption and improves product quality and production efficiency.
[0025] 3. The driving device of the present invention is two groups of powered roller racks, each group consisting of two rollers with flanges and a pressure wheel without flanges. The center position of the pressure wheel is adjustable to meet the production needs of main products of different specifications. And the pressure wheel rack can be opened to facilitate the insertion and removal of workpieces. The function of the pressure wheel is to ensure that the rotor will not jump out of the rotation area defined by the flanges of the two groups of rollers installed opposite to each other when rotating. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 It is a schematic diagram of the aluminum casting of the horizontal shaft rotor in the present invention.
[0027] Figure 2 It is a left view of the left aluminum casting mold in the present invention.
[0028] Figure 3 It is the right side view of the left aluminum casting mold in the present invention.
[0029] Figure 4Schematic diagram of an open slot rotor plate.
[0030] Figure 5 Schematic diagram of a closed slot rotor plate.
[0031] Figure 6 Schematic diagram of the rotor core and mold placed between the pressure wheel and the roller.
[0032] In the figure: 1. burner; 2. smoke hood; 3. left cast aluminum mold; 31. outer circle; 32. inner circle; 33. aluminum leakage hole; 34. countersunk hole; 35. middle hole; 36. circumscribed circle; 37. inner wall of mold cavity; 4. pressure wheel; 5. squirrel cage bar; 6. rotor core; 7. aluminum inlet hole; 8. right cast aluminum mold; 9. bell mouth; 10. funnel; 11. guide cone; 12. roller; 13. limiter; 14. mandrel; 15. guide bar cavity; 16. hinge; 17. pressure wheel frame; 18. hook. DETAILED DESCRIPTION
[0033] In order to enable those skilled in the art to better understand the technical solution, the present invention is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.
[0034] The horizontal axis centrifugal aluminum casting method of the present invention is achieved by using a closed slot-shaped rotor sheet (such as Figure 5 The design scheme (shown in Figure 1) eliminates the need for a rotor cast aluminum center die. Figure 4 For rotors with slots as shown in the figure, the diameter of the circumscribed circle of the slot punch of the rotor punch slot can be designed to be smaller than the inner diameter of the stator and larger than the outer diameter of the finished rotor. When turning the rotor surface, the open slot shape can be achieved by turning off the excess iron. For the punching sheets that have been made into an open slot shape, a 0.3~0.5 mm thick thin plate can be used to wrap the outer circle instead of the middle die.
[0035] like Figure 1-3 As shown, a mold structure for centrifugal aluminum casting of a motor rotor includes a left aluminum casting mold 3, a rotor core 6 and a right aluminum casting mold 8 which are concentrically inserted on a core shaft 14 and blocked by a stopper 13 to form a rotating body. The left aluminum casting mold 3, the right aluminum casting mold 8, the core shaft 14 and the rotor core 6 are clearance fit or loose transition fit. During the aluminum casting process, the core mold rotating body with the core shaft 14 is horizontally placed on a driving device for rotation; the inner cavities of the left aluminum casting mold 3 and the right aluminum casting mold 8 are in the shape of an annular groove, forming the height and outer diameter of the rotor end ring. The inner diameter of the end ring does not contact the mold wall. The rotor core 6 is composed of silicon steel laminations.
[0036] like Figure 1As shown, a burner 1 and a smoke hood 2 are provided on one side of the left aluminum casting mold 3, and an aluminum leakage hole 33 is provided on the end face of the left aluminum casting mold 3 for high-temperature smoke to enter the mold cavity of the left aluminum casting mold 3, allowing the high-temperature smoke generated by the combustion to enter the mold cavity, flow through the guide bar cavity and the aluminum inlet hole 7 of the right aluminum casting mold 8 to heat the mold cavity and the iron core.
[0037] like Figure 2 and Figure 3 As shown, as a further improvement of the above scheme, the left cast aluminum mold 3 includes an outer circle 31, an inner circle 32 and a mold cavity inner wall 37, and an aluminum leakage hole 33 is arranged on the end face; a mold center hole 35 and a countersunk hole 34 are arranged in the middle of the end face to allow the core shaft 14 to pass through, and the countersunk hole 34 accommodates the boss of the core shaft 14; after the core shaft 14 is installed in the left cast aluminum mold 3, the tail of the core shaft 14 protrudes from the mold end face of the left cast aluminum mold 3; the diameter of the circumscribed circle 36 of the aluminum leakage hole 33 is larger than the diameter of the mold cavity inner wall 37 by 10 mm or more.
[0038] As a further improvement of the above scheme, the inner wall 37 of the cavity of the boss in the groove of the left aluminum casting mold 3 is smaller than the distribution circle of the center of the aluminum leakage hole 33; the right mold is opposite to the left mold and has the same structural characteristics.
[0039] like Figure 2 and Figure 3 As shown, high-temperature flue gas enters the mold cavity through a group of aluminum leakage holes 33 on the end face of the left aluminum casting mold 3. This group of holes is distributed in a ring shape on the end face of the left aluminum casting mold 3. When heated, high-temperature flue gas enters through here, and when cast, aluminum liquid overflows from here. The diameter of the circumscribed circle 36 of the aluminum leakage hole should be slightly smaller than the size of the inscribed circle of the rotor plate slot bottom and the design size of the inner circle of the end ring. Otherwise, the bottom of the slot will be dissatisfied. The inner wall of the left aluminum casting mold 3 has a mold draft slope of 1-3 degrees and is trumpet-shaped, small inside and large outside. The depth of the mold cavity is the height of the rotor end ring, and an inner stop is set at the mouth (to avoid too many lines, Figure 2 It is not shown in Figure 1 ), the gap between the stopper and the flange should be small and long enough to ensure that the aluminum liquid will not leak through the gap.
[0040] like Figure 1 As shown, the right part of the right aluminum casting mold 8 is provided with a bell mouth 9 for entering aluminum liquid, and the side end of the bell mouth 9 is provided with a funnel 10.
[0041] The end face of the right aluminum casting mold 8 is the same as the left aluminum casting mold 3. There is a circle of aluminum inlet holes 7 distributed in a ring shape on the end face. They are not only the aluminum liquid inlet channel, but also the high-temperature flue gas outlet for preheating the rotor before aluminum casting. The diameter of the circumscribed circle of the aluminum inlet hole should be slightly smaller than the size of the inscribed circle of the bottom of the rotor core 6 slot. The right aluminum casting mold 8 is the same as the left aluminum casting mold 3. The concave cavity of the mold just accommodates the rotor end ring. The depth and inner diameter of the mold cavity are determined by the design size of the end ring. The right aluminum casting mold 8 has an inward-retracted bell mouth 9 at the mouth for aluminum liquid to enter. The flue gas comes out from here during preheating. The outlet of the funnel 10 is curved so that the aluminum liquid can flow to the bell mouth 9 and enter the mold cavity.
[0042] Different from the traditional design, the left aluminum casting mold 3 and the right aluminum casting mold 8 are not provided with the inner wall forming surface of the end ring. The inner wall of the end ring is close to the mold end surface, and a circle of small holes distributed in a circle leaks the excess aluminum liquid, and the inner wall of the end ring is naturally formed after condensation under the action of centrifugal force. During the aluminum casting process, the aluminum liquid on this surface is in contact with the air, and cools slower than that in contact with the metal mold wall. It condenses here last, so that both the guide bar and the end ring have aluminum liquid to feed the shrinkage. This is the key technology of the present invention to avoid the generation of pores and shrinkage cavities.
[0043] like Figure 1 As shown, the driving devices of the left aluminum casting mold 3 and the right aluminum casting mold 8 are rollers 12 and pressure wheels 4, and the four rollers 12 are all structures with flanges.
[0044] like Figure 1 As shown, the guide cone 11 at the connection between the right cast aluminum mold 8 and the core shaft 14 is detachable, and a limit member 13 is provided on the guide cone 11. The guide cone 11 on the core shaft 14 can be connected to the core shaft 14 by bolts, or can be connected to the core shaft 14 by other detachable methods, and the limit member 13 is a shaft retaining ring, a C-shaped washer, a pin or other similar substitutes. The core shaft 14 may have a straight key bar or an oblique key bar as required. In order to facilitate demoulding, the surface of the core shaft 14 in contact with the rotor core 6 can be designed as a non-continuous circumferential surface, and the center can also be hollow to facilitate water cooling and demoulding by temperature difference.
[0045] like Figure 1 As shown, after the aluminum casting is completed, the aluminum liquid solidifies to form the rotor cage bar 5. Before aluminum casting, measures should be taken to ensure that the punching sheets are stacked and aligned to form a through hole with a neat surface, which is the passage for the flue gas to heat the rotor. According to the design requirements of the motor performance, this channel may be designed as a double-layer or narrow sheet-shaped through hole. The end rings at both ends of the rotor are formed in the annular grooves of the left aluminum casting mold 3 and the right aluminum casting mold 8. The inner circle of the end ring does not contact the inner wall 37 of the mold cavity, and is cooled and formed in the air.
[0046] The invention discloses a process for centrifugal aluminum casting of a motor rotor, comprising the following steps:
[0047] S1, concentrically inserting the left cast aluminum mold 3, the rotor core 6 and the right cast aluminum mold 8 onto the core shaft 14 to obtain a core assembly, and pre-compacting and re-compacting;
[0048] Specifically, the left cast aluminum mold 3 is put on the core shaft 14, and the straight key bar or the oblique key bar for guidance is installed, and it is placed vertically on the working platform of the hydraulic press. For skew slot rotors, use oblique key bars. If it is a straight guide bar rotor, there is no angle between the key and the axis. Pass the core punching sheets on the core shaft 14, and pre-tighten and re-tighten them. Pre-tighten each stack of 50 to 100 mm laminations once, and the pressure between the sheets is 2.5 to 3.0 MPa; after the pre-tightening is completed, press it again to load the limiter 13, and the pressure is 1.8 to 2.0 MPa. Finally, put in the limiter 13. After the mold is installed, a certain prestress is maintained between the core laminations, and there is basically no gap.
[0049] S2, place the iron core assembly installed in S1 between two horizontal rollers 12, and cover with the pressing wheel 4; the iron core assembly rotates horizontally under the drive of the driving device;
[0050] Specifically, the distance between the roller frames is adjusted so that the rotor core 6 assembly with the mold is just placed on the four rollers 12 with flanges, and the pressure roller frame (such as Figure 6 As shown), and adjust the position of the pressure wheel 4 so that the rotor can rotate flexibly and cannot run out of the flange limit of the roller 12. Lock the hook 18 and start the motor to drive the iron core to rotate horizontally;
[0051] Here, one pressing wheel 4 and two rollers 12 are mounted as a group on a pressing wheel frame 17, and the two sets of pressing wheel frames are mounted on the guide rails, and the axial distance is adjustable. The pressing wheel frame 17 is divided into two parts, the lower part is a fixed part, and the upper part is a movable part. The two parts are connected by a hinge 16, and the other side is connected by a hook 18 with a handle. When the hook 18 is released, the upper part can be opened to remove the roller 12 and take out the rotor.
[0052] S3, the high-temperature flue gas generated by the burner enters the mold cavity and the guide bar cavity 15 in the rotor core 6 from the aluminum leakage hole 33 of the left aluminum casting mold 3, so that the mold cavity and the surface of the guide bar cavity 15 are heated, and a temperature field with uniform circumferential distribution and continuous gradient along the axial direction is naturally formed in the rotor core 6;
[0053] Specifically, align the bell mouth of the smoke hood 2 of the burner with the end face of the left ring die, start the driving device to make the rotor rotate at a low speed of 10-30rpm. Start the burner to ignite and heat for about 5 minutes. The high-temperature flue gas enters the mold cavity and the rotor core guide bar cavity 15 through the aluminum leakage hole 33 on the end face of the left aluminum casting mold 3 to heat the mold and the core, and naturally forms a temperature field in the rotor core 6 that is uniformly distributed in the circumferential direction and has a continuous gradient along the axial direction.
[0054] In the process method of the present invention, the lamination assembly of the rotor core 6 is not pre-baked in a preheating furnace, but is only heated from one end by high-temperature flue gas formed by flames before the injection of molten aluminum. Heating does not require waiting for the entire core to be heated evenly, and the process method of heating while rotating has ensured the uniformity of heating of the rotor along the circumferential direction. Unlike vertical centrifugal aluminum casting, the rotor core 6 of the preheating method of the present invention is heated unevenly in the axial direction, presenting a continuously changing temperature difference, which is conducive to the sequential condensation of the rotor aluminum bars. This is a key technology to avoid the formation of broken thin bars. When casting aluminum, the rotor rotates horizontally or approximately horizontally on a rollable bracket, with the left side slightly higher. Molten aluminum is injected into the assembly while the horizontal axis rotates until molten aluminum overflows from the other end.
[0055] S4, the aluminum liquid is poured from the funnel 10 into the bell mouth 9 of the right aluminum casting mold 8 and injected into the mold cavity through the aluminum inlet hole 7. When the aluminum liquid overflows from the aluminum leakage hole 33, the pouring of the aluminum liquid can be stopped;
[0056] Pour the 740-750 degree aluminum liquid into the rotor right aluminum casting mold 8 through the funnel 10. Under the action of centrifugal force, the aluminum liquid will fill the end ring cavity of the left aluminum casting mold 3 and the right aluminum casting mold 8 and the core lamination guide bar cavity 15 until the aluminum liquid overflows from the left end and the casting can be stopped;
[0057] S5, stop firing, the rotor core mold assembly speeds up and keeps rotating at a high speed until the aluminum liquid is completely solidified and stops rotating;
[0058] Turn off the heat, speed up to over 100 rpm, keep rotating until the surface solidifies, and then rotate for about three minutes, then stop the machine and open the mold;
[0059] S6. After stopping the machine, use pneumatic or electric wrench, pull code, or hydraulic press to remove the mold.
[0060] Use tools to remove the bolts and guide cone 11 on the guide cone 11, use a pull code to remove the right cast aluminum mold 8, put the rotor with the left cast aluminum mold 3 on the workbench of the hydraulic press, use a long rod to press out the core shaft 14, and then use a pull code to remove the left cast aluminum mold 3 at the left end.
[0061] For a mandrel 14 with a larger diameter, the outer surface in contact with the inner circle of the laminations can be partially cut off along the circumference to reduce the contact area between the mandrel 14 and the rotor punching, so that the mandrel 14 can be removed more easily. This can extend the service life of the mandrel 14. A through hole is drilled in the center of the mandrel 14, and cold water is injected before demoulding to cool the mandrel 14 before the core. Demolding by temperature difference is also conducive to extending the service life of the mandrel 14. These two solutions can be used separately or not.
[0062] The rotor punchings used in this process need to be closed slot shaped. Figure 3 The opening slot in the Figure 4 Otherwise, wrapping measures need to be taken to prevent the aluminum liquid from leaking sideways.
[0063] Rotor cast aluminum quality assessment method:
[0064] Surface observation: dissect the rotor, remove the iron sheet, and observe the integrity of the aluminum bars. The aluminum bars should not be thinned or have surface holes.
[0065] Test of aluminum density, porosity and filling rate: Cut the conductor bar sample and the end ring sample into several small pieces, hang them on the iron frame and weigh them to get gi1, then immerse the same sample in water and weigh them to get weight gi2;
[0066] The volume of sample i is Vi=Σgi1-Σgi2.
[0067] The density of the sample population р=Σgi1 / ΣVi;
[0068] The sample population filling degree % = р / 2.7;
[0069] Sample porosity = 1-sample overall filling percentage.
[0070] The porosity of the rotor produced by the present invention is lower than 3%, and currently no defects such as broken strips or thin strips have been found.
[0071] It should be noted that, in this article, the terms include, contain or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the present invention. The above examples are only used to help understand the method of the present invention and its core idea. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the invention to other occasions without improvement, should be regarded as the protection scope of the present invention.
Claims
1. A mold structure for centrifugal aluminum casting of a motor rotor, characterized in that: The left aluminum casting mold (3), the rotor iron core (6) and the right aluminum casting mold (8) are concentrically inserted on the core shaft (14), and are blocked by the limiter (13) to form a rotating body, which is horizontally placed on the driving device for rotation; the inner cavity of the left aluminum casting mold (3) and the right aluminum casting mold (8) has an annular groove, and the end surface has a hole, and the aluminum liquid in the cavity is cooled under the action of centrifugal force to form a rotor end ring; A smoke hood (2) is provided on one side of the left aluminum casting mold (3), and the smoke hood (2) is connected to the burner (1). An aluminum leakage hole (33) is provided on the end surface of the left aluminum casting mold (3) to allow high-temperature smoke generated by combustion to enter the mold cavity and flow through the guide bar cavity (15) and the aluminum inlet hole (7) of the right aluminum casting mold (8) to heat the mold cavity and the iron core; The mouth of the right aluminum casting mold (8) is provided with a bell mouth (9) for entering aluminum liquid, and a funnel (10) is provided at the side end of the bell mouth (9); The driving devices of the left cast aluminum mold (3) and the right cast aluminum mold (8) are a roller (12) and a pressure wheel (4).
2. The mold structure of centrifugal aluminum casting of a motor rotor according to claim 1, characterized in that: The left aluminum casting mold (3) comprises an outer circle (31), an inner circle (32) and a mold cavity inner wall (37), and an aluminum leakage hole (33) is arranged on the end face; a mold center hole (35) and a countersunk hole (34) are arranged in the middle of the end face to allow the core shaft (14) to pass through, and the countersunk hole (34) accommodates the boss of the core shaft (14); after the core shaft (14) is installed in the left aluminum casting mold (3), the tail of the core shaft (14) protrudes from the mold end face of the left aluminum casting mold (3); the diameter of the circumscribed circle (36) of the aluminum leakage hole (33) is greater than the diameter of the mold cavity inner wall (37) by 10 mm or more.
3. The mold structure of centrifugal aluminum casting of a motor rotor according to claim 2, characterized in that: The diameter of the inner wall (37) of the cavity of the boss in the groove of the left aluminum casting mold (3) is smaller than the distribution circle of the center of the aluminum leakage hole (33); the right aluminum casting mold (8) is opposite to the left aluminum casting mold (3) and has the same structural characteristics.
4. The mold structure of centrifugal aluminum casting of a motor rotor according to claim 1, characterized in that: The roller (12) has a flange structure to limit the axial movement of the iron core mold assembly; the roller (12) is connected to an electric motor or other power device through a speed reduction mechanism, and the speed is adjustable.
5. The mold structure of centrifugal aluminum casting of a motor rotor according to claim 1, characterized in that: A detachable guide cone (11) is provided at the end of the core shaft (14), and a limiter (13) is provided at the connection with the guide cone (11) to limit the position of the right cast aluminum mold (8) and maintain prestress on the lamination stack of the rotor core (6).
6. The mold structure of centrifugal aluminum casting of a motor rotor according to claim 1, characterized in that: A bar guide cavity (15) is provided in the rotor core (6) for forming rotor cage bars (5) after the aluminum liquid solidifies after aluminum casting is completed; end rings at both ends of the rotor are formed in the annular grooves of the left aluminum casting mold (3) and the right aluminum casting mold (8); the inner circle of the end ring does not contact the inner wall (37) of the mold cavity and is cooled and formed in the air.
7. A process for centrifugal aluminum casting of a motor rotor, using a mold structure for centrifugal aluminum casting of a motor rotor according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, concentrically inserting the left cast aluminum mold (3), the rotor core (6) and the right cast aluminum mold (8) onto the core shaft (14), pre-compacting and re-compacting, to obtain a core assembly; S2, placing the iron core assembly assembled in S1 between two sets of horizontal rollers (12), and covering them with a pressure wheel (4); the iron core assembly is driven to rotate horizontally by a speed-adjustable driving device; S3, the high-temperature flue gas generated by the burner (1) enters the mold cavity and the guide bar cavity (15) in the rotor core (6) from the aluminum leakage hole (33) of the left aluminum casting mold (3), so that the mold cavity and the surface of the guide bar cavity (15) are heated, and a temperature field with uniform circumferential distribution and continuous gradient along the axial direction is naturally formed in the rotor core (6); S4, the aluminum liquid is poured from the funnel (10) into the bell mouth (9) of the right aluminum casting mold (8) and injected into the mold cavity through the aluminum inlet hole (7). When the aluminum liquid overflows from the aluminum leakage hole (33), the pouring of the aluminum liquid can be stopped; S5, stop firing, speed up the core assembly and keep rotating at high speed until the aluminum liquid is completely solidified and stops rotating; S6. After stopping the machine, use pneumatic, electric or hydraulic tools to remove the mold.
8. The process for centrifugal aluminum casting of a motor rotor according to claim 7, characterized in that: During the aluminum casting process, the rotor core (6) and the assembly formed by the mold rotate horizontally.