Extrusion forming method and extrusion device for aluminum end ring of cast aluminum rotor of motor

Abstract

The present disclosure relates to the technical field of die casting manufacturing, and particularly relates to a motor cast aluminum rotor aluminum end ring extrusion forming method and an extrusion device, a die casting structure comprises a rear mold core, an extrusion hole and an extrusion needle, 12-20 extrusion holes are arranged on the end face of the aluminum end ring of the rear mold core, and the extrusion needle is inserted into the extrusion hole; the method comprises the following steps: reserving a backfill space between the front end of the extrusion needle and the end face of the aluminum end ring of the rear mold core, and injecting aluminum liquid into the mold cavity on one side of the rear mold core and the backfill space; the extrusion needle extrudes the aluminum liquid in the backfill space into the rotor aluminum end ring formed by the mold cavity under a set extrusion force. In the die casting process of the present disclosure, the aluminum liquid enters the mold cavity and the backfill space at the same time, and before the rotor is solidified and formed, the aluminum liquid in the backfill space is instantaneously extruded into the rotor under a set extrusion force, and by improving the process and device of die casting forming, the thermal shrinkage holes and pores of the rotor can be effectively eliminated / reduced, and the porosity can be controlled to be less than 1%.

Description

Technical Field

[0001] This disclosure relates to the field of die-casting manufacturing technology for cast aluminum rotors of electric motors, and in particular to a method and extrusion apparatus for extruding aluminum end rings of cast aluminum rotors of electric motors. Background Technology

[0002] During the production process, aluminum end rings of cast aluminum rotors for asynchronous squirrel-cage motors often exhibit heat shrinkage cavities and air holes. These defects can cause problems such as excessive motor resistance, reduced power factor, large slip, low conductivity, high power consumption, and heat generation. Large shrinkage cavities can also lead to excessive initial dynamic balance of the rotor. When used in motors for new energy vehicles, where the rotor speed must reach over 20,000 rpm, this can cause motor vibration, and in more serious cases, burnout or rotor disintegration. Summary of the Invention

[0003] To address at least the above-mentioned technical problems in the prior art, this disclosure provides a method and extrusion apparatus for extruding aluminum end rings of cast aluminum rotors for electric motors.

[0004] This disclosure provides a method for extruding an aluminum end ring for a cast aluminum rotor of an electric motor. The method is used for forming the aluminum end ring of the rotor. The die-casting structure includes a rear mold core, extrusion holes, and an extrusion needle. The aluminum end ring end face of the rear mold core is provided with 12 to 20 extrusion holes, and the extrusion needle is inserted into the extrusion holes. The method includes the following steps: reserving a backfill space between the front end of the extrusion needle and the end face of the aluminum end ring of the rear mold core; injecting aluminum liquid into the mold cavity on one side of the rear mold core and the backfill space; and under a set extrusion pressure, the extrusion needle extrudes the aluminum liquid in the backfill space into the rotor aluminum end ring formed by the mold cavity.

[0005] This disclosure also provides an extrusion apparatus for forming an aluminum end ring of a rotor, comprising a die-casting structure and a force-applying structure; the die-casting structure includes a rear mold core, extrusion perforations, and extrusion needles, wherein a plurality of the extrusion perforations communicate with the end face of the aluminum end ring of the rear mold core and the plurality of the extrusion perforations cover the end face of the aluminum end ring of the rear mold core, and the extrusion needles are inserted into the extrusion perforations; the end of the extrusion needles is connected to the force-applying structure for applying a set extrusion force to the front end of the extrusion needles, so that the aluminum material in the backfill space of the extrusion perforations can be extruded into the rear mold core.

[0006] In some embodiments, the plurality of extrusion perforations are located on the aluminum end ring face of the rear model core in a ring-shaped distribution.

[0007] In some embodiments, the device further includes a compression needle plate and a compression needle base plate, wherein the end of the compression needle is vertically fixed between the compression needle plate and the compression needle base plate, and the compression needle base plate is connected to the force-applying structure.

[0008] In some embodiments, a limiting block is further included, the limiting block being located between the moving mold base plate of the die-casting structure and the extrusion needle plate; the force-applying structure pushes the extrusion needle base plate, causing the extrusion needle plate to abut against the end face of the limiting block, thereby limiting the allowable distance that the extrusion needle can advance when extruding.

[0009] In some embodiments, the total volume of aluminum material in the extrusion perforation backfill space is 6% to 11% of the volume of the aluminum end ring of the rear mold core.

[0010] In some embodiments, the extrusion needle includes a thick rod portion and a thin rod portion, the thin rod portion being inserted into the extrusion perforation; the diameter of the thin rod portion is 8 mm to 12 mm.

[0011] In some embodiments, the aluminum end ring face of the rear mold core is annular, and the plurality of extrusion perforations are uniformly distributed in a ring shape on the aluminum end ring face of the rear mold core.

[0012] In some embodiments, the thrust source of the force-applying structure is the extrusion cylinder of the die-casting machine. The extrusion plate of the die-casting machine pushes out through the force-applying rod and acts on the base plate of the extrusion needle. The applied set extrusion pressure is 220 kN to 270 kN. On average, each extrusion needle must provide a thrust of more than 12.6 kN, and the end face of each extrusion needle rod must withstand a pressure of more than 160 MPa.

[0013] In some embodiments, the die-casting structure includes a mold frame with multiple templates stacked on top of each other, and the rear mold core is placed in the internal cavity of the mold frame.

[0014] This disclosure provides a method and apparatus for extruding aluminum end rings of a cast aluminum rotor for electric motors. During the rotor die-casting process, a backfill space is reserved in the extrusion perforation of the rear mold core. During die-casting, the die-cast aluminum material simultaneously enters the mold cavity and the backfill space. Before the aluminum end ring solidifies, the die-cast aluminum material in the backfill space is instantaneously extruded into the rotor under a set extrusion pressure. This technical solution, by improving the die-casting process and apparatus, can effectively eliminate / reduce thermal shrinkage cavities and porosity in the rotor, and its porosity can be controlled to less than 1%. Attached Figure Description

[0015] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which:

[0016] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0017] Figure 1A flowchart illustrating the method for extruding aluminum end rings of a cast aluminum rotor for an electric motor, as provided in this embodiment of the disclosure.

[0018] Figure 2 This is a schematic diagram of the extrusion device provided in an embodiment of the present disclosure;

[0019] Figure 3 Cross-sectional view of the extrusion apparatus provided in the embodiments of this disclosure. Figure 1 ;

[0020] Figure 4 Cross-sectional view of the extrusion apparatus provided in the embodiments of this disclosure. Figure 2 ;

[0021] Figure 5 A partial schematic diagram of the backfill space in the extrusion apparatus provided in this embodiment of the present disclosure. Figure 1 ;

[0022] Figure 6 A partial schematic diagram of the backfill space in the extrusion apparatus provided in this embodiment of the present disclosure. Figure 2 ;

[0023] Figure 7 This is a partial schematic diagram of the extrusion perforation of the rear mold core in the extrusion device provided in the embodiments of this disclosure;

[0024] Figure 8 This is a schematic diagram of the rotor in the extrusion device provided in the embodiments of this disclosure;

[0025] Figure 9 This is a schematic diagram of the stroke limitation of the limiting block in the extrusion device provided in the embodiments of this disclosure.

[0026] In the picture:

[0027] 1: Die-casting structure; 2: Force-applying structure; 3: Extrusion needle plate; 4: Extrusion needle base plate;

[0028] 5: Rotor; 6: Limiting block; 11: Rear mold core; 12: Extrusion perforation;

[0029] 13: Extrusion pin; 14: Die frame; 15: Backfill space; 16: Moving die base plate; 17: Lifting cylinder; 18: Ejector bar;

[0030] 51: Aluminum end ring; 52: Fixed mandrel. Detailed Implementation

[0031] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0032] This disclosure provides a die-casting method, wherein the die-casting structure includes a rear mold core, extrusion holes, and extrusion pins. The rear mold core has 12 to 20 extrusion holes on its aluminum end ring face, and the extrusion pins are inserted into these extrusion holes. This die-casting structure may also refer to... Figures 2 to 9 The extrusion apparatus provided in the embodiments of this disclosure is shown.

[0033] like Figure 1 As shown, the method includes the following steps:

[0034] Step S1: A backfill space is reserved between the front end of the extrusion needle and the end face of the aluminum end ring of the rear mold core. The aluminum liquid is then injected into the mold cavity and backfill space on one side of the rear mold core. The distance the extrusion needle travels towards the mold cavity within the extrusion piercing is equal to the distance between the limiting block and the extrusion needle plate. Before the aluminum liquid is injected, the die-casting machine's extrusion plate and the connected tie rod pull the extrusion needle base plate back to the origin starting position of the die-casting equipment, creating a backfill space between the front end of the extrusion needle rod and the mold cavity on one side of the rear mold core. After die-casting begins, the aluminum liquid is gradually injected into the mold cavity and backfill space on one side of the rear mold core.

[0035] During the injection process, the aluminum liquid is injected into the mold cavity and the backfill space. The rapid pushing of the molten aluminum by the punch in the material chamber causes the molten aluminum to tumble and mix with air. This air, along with some of the air that could not be smoothly discharged from the mold cavity during the injection process, forms a dense network of pores in the rear aluminum end ring (short-circuit ring) after the rotor is formed and cooled.

[0036] In addition, because the volume of aluminum in the liquid state is greater than that in the solid state, a large area of ​​heat shrinkage holes will also be formed in the rear aluminum end ring (short-circuit ring) after the rotor is formed and solidified.

[0037] Step S2: Under the set extrusion pressure, the extrusion needle forces the molten aluminum in the backfill space into the rear mold cavity. Before the molten aluminum in the mold cavity solidifies, the extrusion needle forces the molten aluminum in the backfill space into the aluminum end ring of the rear mold core.

[0038] Because some molten aluminum was injected again into the rear mold cavity, the pores in the rear aluminum end ring of the rotor were compressed, making the pore volume smaller and fewer. In other words, the heat shrink holes were filled and compacted, making the area of ​​the heat shrink holes smaller or non-existent, thereby eliminating / reducing the heat shrink holes and pores of the rotor.

[0039] This disclosure provides an extrusion device, which can be based on, for example, Figure 1 The method shown enables the die-casting of the rotor. Specifically, the extrusion device includes a die-casting structure and a force-applying structure; the die-casting structure performs the die-casting operation on the rotor, and the force-applying structure applies force to the extrusion needle to fulfill the extrusion requirements. The following description, in conjunction with the accompanying drawings, explains the components of the extrusion device and the connections between them.

[0040] like Figures 2 to 9 As shown, the die-casting structure 1 includes a rear mold core 11, extrusion piercing holes 12, and extrusion pins 13. Multiple extrusion piercing holes 12 are connected to the end face of the aluminum end ring 51 of the rear mold core 11, and multiple extrusion piercing holes 12 cover the end face of the aluminum end ring 51 of the rear mold core 11. Extrusion pins 13 are inserted into the extrusion piercing holes 12. The end of the extrusion pin 13 is connected to the force-applying structure 2, which is used to apply a set extrusion force to the front end of the extrusion pin 13 so that the aluminum material in the backfill space in the extrusion piercing hole 12 can be extruded into the rear mold core 11.

[0041] During use, under the action of the force-applying structure 2 (only the connecting part structure is shown in the figure), the extrusion needle 13 is pulled back to the starting position set by the extrusion plate of the die-casting equipment in a direction away from the rear mold core 11, so that there is a certain distance between the extrusion needle 13 and the rear mold core 11, thereby forming the backfill space 15. After the die-casting operation starts, aluminum is hydraulically injected into the mold cavity of the rear mold core 11 and the backfill space 15.

[0042] The volume of the backfill space 15 is determined based on the porosity of the rotor rear aluminum end ring 51 within the mold cavity. For example, using a conventional process, the porosity of the rotor rear aluminum end ring 51 after die casting is 6% to 11%, meaning that the rotor rear aluminum end ring 51 within the mold cavity has 6% to 11% backfill space. Therefore, the backfill space 15 within the extrusion perforation 12 can be set to an equal volume, meaning the volume of the molten aluminum within the extrusion perforation 12 is 6% to 11% of the volume of the mold rear aluminum end ring cavity.

[0043] One key aspect is calculating the appropriate advance distance for each extrusion needle 13. This can be determined by dividing the volume of the rear model core aluminum end ring 51 by 6%-11% ÷ the number of extrusion needles ÷ the cross-sectional area of ​​the thin end face of the extrusion needle, thus determining the length that should be reserved within the extrusion perforation 12 for each backfill space.

[0044] In this embodiment, the extrusion perforations 12 are not located locally on the end face of the aluminum end ring 51 of the rear mold core 11, but are distributed in a ring shape across the entire end face of the aluminum end ring 51. For example, multiple extrusion perforations 12 are evenly distributed on the end face of the aluminum end ring 51. Heat shrinkage cavities and air holes may appear at any position below the end face of the aluminum end ring 51 of the rotor 5. Therefore, evenly distributing multiple extrusion perforations 12 helps to eliminate heat shrinkage cavities and air holes as a whole, thereby improving the overall die-casting quality of the rotor 5.

[0045] For example, the number of extrusion perforations 12 is set such that one hole is provided at a center distance of 18-23 mm on the end face of the aluminum end ring 51; the extrusion perforations 12 are distributed in a ring at the middle position on the end face of the aluminum end ring 51; the diameter of the extrusion perforations 12 is selected according to the width of the aluminum end ring 51.

[0046] Continue to refer to Figures 2 to 9 As shown, the end of the extrusion needle 13 away from the aluminum end ring 51 end face of the rear mold core 11 is provided with an extrusion needle plate 3 and an extrusion needle base plate 4. The end of the extrusion needle 13 is vertically fixed between the extrusion needle plate 3 and the extrusion needle base plate 4. The extrusion needle base plate 4 is connected to the force application structure 2. The hardness of the extrusion needle base plate 4 needs to be above HRC42 to avoid the plate surface from being dented due to long-term pressure on the shoulder of the extrusion needle 13.

[0047] In use, multiple extrusion needles 13 need to move synchronously. Therefore, one end of the extrusion needle 13 can be connected between the extrusion needle plate 3 and the extrusion needle base plate 4. The extrusion needle base plate 4 is then connected to the force-applying structure. The force-applying structure 2 drives the extrusion needle plate 3 and the extrusion needle base plate 4 to move, thereby realizing the synchronous movement of multiple extrusion needles 13.

[0048] For the motion control of the extrusion needle 13, it is necessary to control the extrusion needle 13 to move to a designated position, that is, the position of the front end face of the extrusion needle 13 is outside the end face of the aluminum end ring 51 of the rear mold core 11. For example, the front end face of the extrusion needle 13 is flush with the end face of the aluminum end ring 51 of the rear mold core 11. In this embodiment of the present disclosure, the travel of the extrusion needle plate 3 / extrusion needle base plate 4 and the extrusion needle 13 is limited by setting a limiting block 6.

[0049] For example, the limiting block 6 is located between the moving mold base plate 16 and the extrusion pin plate 3 of the die-casting structure 1. The limiting block 6 is controlled by the lifting cylinder 17 to move up and down. Before the mold closes, the lifting cylinder 17 lowers the inner end face of the limiting block 6 to the surface of the moving mold base plate 16 and places it down to the center of the mold rotor. After the die-casting machine completes the injection and extrusion actions, before the mold opens, the pull rod pulls the extrusion pin base plate 4 back to its original starting position. The lifting cylinder 17 raises the limiting block 6 above the top of the moving mold base plate 16 of the mold frame. The die-casting machine then performs the mold opening action. At this time, the extrusion pin plate 3 and the extrusion pin base plate 4 return to the normal die-casting extrusion action. However, when the rotor is extruded, the ejector bar 18 located in the center is actually pushed. The ejector bar 18 then pushes the bottom of the fixed mandrel 52 in the middle of the rotor core to push the entire die-cast rotor out of the mold cavity.

[0050] The force-applying structure 2 pushes the extrusion needle base plate 4, causing the extrusion needle plate 3 to abut against the limiting block 6, thereby limiting the allowable forward distance of the extrusion needle 13 during extrusion. The force-applying structure 2 provides a certain instantaneous thrust, which prevents the extrusion needle plate 3 and the extrusion needle 13 on it from continuing to move through the limiting block 6. For example, the protrusion height of the die-casting raw material after extrusion in the backfill space 15 is controlled to be less than 0.5 mm.

[0051] In this embodiment, the diameter of the extrusion needle 13 is set according to the force applied by the force-applying structure 2 and the number of extrusion needles 13. For example, the extrusion needle 13 includes a thick rod portion and a thin rod portion, with the thin rod portion passing through the extrusion hole 12. The design of the thick rod portion is mainly to strengthen the rigidity of the entire extrusion needle and prevent it from bending or breaking during instantaneous extrusion. Therefore, the shoulder section of the extrusion needle 13, about 100mm long, is reinforced. The outer diameter of the thin rod portion of the extrusion needle 13 and the shaft hole clearance of the extrusion hole diameter are optimally 0.035±0.005mm. When the clearance is less than 0.03mm, the core and extrusion needle 13 will come into contact with molten aluminum, causing a rapid increase in temperature. Under the influence of thermal expansion, the core and extrusion needle will break. The pressure needle 13 may get stuck in the extrusion piercing, causing it to be unable to extrude or to encounter excessive resistance, resulting in a decrease or failure of the extrusion effect. When the clearance is greater than 0.04mm, under production conditions with aluminum temperatures above 700℃, aluminum is prone to "leaking" between the extrusion piercing 12 and the extrusion needle 13. The larger the clearance, the greater the chance of aluminum "leaking," which can cause scratches on the wall of the extrusion piercing 12. When the extrusion piercing 12 is scratched, the aluminum shavings remaining on the hole wall will also cause excessive resistance, making it impossible to extrude. In actual operation, if the clearance is effectively controlled and the extrusion needle 13 is regularly lubricated, the mold core can be used for more than 15,000 mold cycles, and the extrusion needle can be used for more than 10,000 mold cycles before replacement. For example, the diameter of the thin rod part is 8 mm to 12 mm.

[0052] For example, the extrusion pin 13 is made of SKD61 steel and must be salt bath quenched to a hardness of HRC45-47 and surface nitrided; the back mold core 11 is made of SKD61 steel and quenched to a hardness of HRC47-49 and surface nitrided; the extrusion perforation 12 on the core must also be treated with a surface hardening coating to increase the surface hardness of the hole wall to HRC60 or above, which can prevent scratches on the surface of the hole wall of the extrusion perforation 12 and extend its service life.

[0053] In this embodiment, the force-applying structure 2 needs to meet the extrusion force requirements and the need for instantaneous extrusion. That is, under the action of the force-applying structure 2, it needs to ensure that multiple extrusion needles 13 move synchronously and can move to the designated position.

[0054] For example, the thrust source of the force-applying structure 2 is the extrusion cylinder of the die-casting machine, and the pressure source of the extrusion cylinder is generated by the motor pump of the die-casting machine itself or by adding a nitrogen cylinder to assist the hydraulic system, providing a larger flow and faster response hydraulic pressure, thereby increasing the kinetic energy of the instantaneous ejection force output of the extrusion cylinder; the ejection thrust of the die-casting machine's extrusion plate acts on the extrusion needle base plate 4 through the force-applying rod, and the die-casting machine is used to apply a set extrusion force of 220 kN to 270 kN to the extrusion needle 13. On average, each extrusion needle must provide a thrust of more than 12.6 kN, and the end face of each extrusion needle rod must withstand a pressure of more than 160 MPa.

[0055] In this embodiment, the die-casting structure 1 includes a mold frame 14 with multiple templates stacked on top of each other, and a rear mold core 11 is placed inside the multiple templates. The mold frame 14 is assembled by stacking, and the number or thickness of the templates in the mold frame 14 can be adjusted according to actual usage requirements to achieve the purpose of matching the stacking length of the motor rotor core. This method can further improve the versatility of the die-casting structure 1.

[0056] This disclosure provides a method and apparatus for extruding an aluminum end ring of a cast aluminum rotor for an electric motor. During the die-casting process of the rotor 5, a backfill space 15 is reserved at the end of the extrusion perforation 12. During die-casting, molten aluminum simultaneously enters the mold cavity of the rear mold core 11 and the backfill space 15. Before the rotor 5 solidifies, the molten aluminum in the backfill space 15 is instantaneously extruded into the rotor 5 with a set extrusion pressure. This technical solution, by improving the die-casting process and apparatus, can effectively eliminate / reduce heat shrinkage cavities and air holes in the rear aluminum end ring 51 of the rotor, and its porosity can be controlled to be less than 1%.

[0057] The following describes the extrusion molding method and extrusion device for the aluminum end ring of the cast aluminum rotor mold of the die-cast asynchronous motor as an example.

[0058] First, a motor core is inserted into the mold cavity of the die frame 14 of the die casting structure 1. The starting position of the extrusion needle 13 is controlled by the die casting machine. A backfill space 15 is reserved between the end of the extrusion needle 13 and the mold cavity. Then, molten aluminum is injected into the material tube and the injection operation is performed by the punch, so that the molten aluminum is quickly filled into the mold cavity and the backfill space 15.

[0059] In this design, the aluminum end ring 51 of the rear mold core 11 is circular, and the multiple extrusion holes 12 are evenly distributed in a ring shape at the middle of the circular end face of the aluminum end ring 51 of the rear mold core 11. For example, 15 to 17 extrusion holes 12 are provided, and correspondingly 15 to 17 extrusion needles 13 are provided.

[0060] Before the molten aluminum solidifies in the mold cavity, the die-casting machine's extrusion plate is instantly pushed. The die-casting machine's pump or nitrogen cylinder provides the kinetic energy source for the required ejection force, causing the molten aluminum in the backfill space 15 to be squeezed and compressed into the mold cavity. Finally, the extrusion pin 13 is reset, and the mold opening operation is performed.

[0061] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0063] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An extrusion apparatus for forming the rear aluminum end ring (51) of a rotor (5), characterized in that, It includes a die-casting structure (1) and a force-applying structure (2); The die-casting structure (1) includes a rear mold core (11), extrusion holes (12) and extrusion needles (13). The number of extrusion holes (12) is 12 to 20. Multiple extrusion holes (12) are connected to the aluminum end ring end face of the rear mold core (11), and multiple extrusion holes (12) are distributed throughout the aluminum end ring end face of the rear mold core (11). The extrusion needles (13) are inserted into the extrusion holes (12). The end of the extrusion needle (13) is connected to the force-applying structure (2) to apply a set extrusion force to the front end of the extrusion needle (13) so that the aluminum material in the backfill space (15) in the extrusion perforation (12) can be extruded into the end ring (51) of the rear mold core. It also includes an extrusion needle plate (3), an extrusion needle base plate (4), and a limiting block (6). The end of the extrusion needle (13) is vertically fixed between the extrusion needle plate (3) and the extrusion needle base plate (4). The extrusion needle base plate (4) is connected to the force-applying structure (2). The limiting block (6) is located between the moving mold base plate (16) of the die-casting structure (1) and the extrusion needle plate (3). The force-applying structure (2) pushes the extrusion needle base plate (4) so ​​that the extrusion needle plate (3) abuts against the end face of the limiting block (6) to limit the distance that the extrusion needle (13) can advance when it is extruding. The limiting block (6) is connected to a lifting cylinder (17). The lifting cylinder (17) is used to control the up and down movement of the limiting block (6). The thrust source of the force-applying structure (2) is the extrusion cylinder of the die-casting machine; The extrusion needle (13) includes a thick rod portion and a thin rod portion, the thin rod portion being inserted into the extrusion perforation (12); The extrusion plate of the die-casting machine exerts a thrust through the force bar onto the base plate (4) of the extrusion needle. The applied extrusion force is 220 kN to 270 kN. On average, each extrusion needle must provide a thrust of more than 12.6 kN, and the end face of each extrusion needle rod must withstand a pressure of more than 160 MPa.

2. The extrusion device according to claim 1, characterized in that, The multiple extrusion perforations (12) are located on the aluminum end ring face of the rear model core (11) and are distributed in a ring.

3. The extrusion device according to claim 1 or 2, characterized in that, The total volume of aluminum material in the backfill space (15) of the extrusion perforation (12) is 6% to 11% of the volume of the aluminum end ring (51) of the rear mold core (11).

4. The extrusion device according to claim 1 or 2, characterized in that, The diameter of the thin rod portion is 8 mm to 12 mm.

5. The extrusion device according to claim 1 or 2, characterized in that, The aluminum end ring of the rear model core (11) is circular, and the plurality of extrusion holes (12) are evenly distributed in a ring shape around the aluminum end ring of the rear model core (11).

6. The extrusion device according to claim 1 or 2, characterized in that, The die-casting structure (1) includes a mold frame (14) with multiple templates stacked on top of each other, and the rear mold core (11) is placed in the internal mold cavity of the mold frame (14).

Images