A rotor assembly and method of making the same

Abstract

This application discloses a rotor assembly and its manufacturing method. The rotor assembly includes a shaft portion and a gear portion connected to the shaft portion. At least a portion of the shaft portion is formed by a first insert, and the gear portion includes a second insert, a first molding portion, and a second molding portion. The first insert is provided with a support platform, the second insert is sleeved on the outer periphery of the support platform and coaxially arranged with the first insert, the first molding portion covers the support platform and the second insert, and the second molding portion is connected to one side of the first molding portion and is provided with transmission teeth. The manufacturing method includes insert assembly, a first injection molding to form the first molding portion, and a second injection molding to form the second molding portion, and demolding is completed by a positioning structure and a sequential core-pulling structure. This rotor assembly can improve the coaxiality, connection strength, and transmission accuracy between the shaft portion and the gear portion, while achieving stable and efficient mass production.

Description

Technical Field

[0001] This application relates to the field of injection molding technology, and in particular to a rotor assembly and its preparation method. Background Technology

[0002] Rotor assemblies are widely used in micro motors, speed reduction mechanisms, robots, sensors, and various automated equipment. They are usually an important part of the power transmission mechanism, which realizes power output by connecting with the drive source and completes power transmission by meshing with other transmission components through a gear structure.

[0003] Most rotor assemblies in existing technologies are formed from a single piece of metal material, using machining processes such as turning, milling, and grinding to create the shaft and gear structure. Although this type of structure has high mechanical strength and dimensional accuracy, it involves many machining steps, has a long production cycle, and low material utilization, resulting in high manufacturing costs and making it difficult to meet the needs of mass production.

[0004] With the development of injection molding technology, the use of insert molding to fabricate rotor assemblies has gradually attracted attention. This process integrates metal inserts with the plastic structure, effectively reducing material and processing costs and improving production efficiency while ensuring structural strength. However, during the insert molding process of rotor assemblies, the high coaxiality requirements between the shaft and gear structures, coupled with the need for high contour and meshing accuracy in the gear area, can easily lead to problems such as insufficient coaxiality between the gear and shaft, insufficient strength of the plastic components, weak bonding between different materials, and unstable molding accuracy. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a rotor assembly and a method for manufacturing the same, which can improve the connection strength and coaxiality between the shaft and the gear, thereby improving the transmission accuracy.

[0006] The present invention provides a rotor assembly, including a shaft portion and a gear portion connected to the shaft portion; at least a portion of the shaft portion is formed by a first insert, and the gear portion includes a second insert, a first forming portion, and a second forming portion; the first insert has two opposite ends extending along the axial direction of the rotor assembly, one end of which forms a connecting shaft for connecting to a drive source, and the other end is provided with a support platform for supporting the second insert; the second insert is sleeved on the outer periphery of the support platform and coaxially arranged with the first insert, the first forming portion covers the support platform and the second insert, the second forming portion is connected to the side of the first forming portion away from the first insert, and the inner side of the second forming portion is provided with transmission teeth.

[0007] In one embodiment, a plurality of biting teeth are provided on the side where the first molding part is connected to the second molding part. The plurality of biting teeth are spaced apart along the circumference of the first molding part. The second molding part is provided with a plurality of fitting parts corresponding to the plurality of biting teeth. Each biting tooth is fitted into the corresponding fitting part.

[0008] In one embodiment, the first molding portion and the second molding portion are made of different materials.

[0009] In one embodiment, the first molding part is molded using glass fiber reinforced polyamide material, and the second molding part is molded using polyamide material.

[0010] The present invention also provides a method for manufacturing a rotor assembly, used to manufacture the rotor assembly of the above embodiments, the method comprising: S1. Provide a first insert and a second insert, and fit the second insert onto the outer periphery of the support platform of the first insert so that the second insert is coaxially arranged with the first insert; S2. Perform a first injection molding on the first insert and the second insert to form a first molded part covering the support platform and the second insert; S3. Perform a second injection molding on the semi-finished product after the first injection molding to form a second molding part on the side of the first molding part away from the first insert, so as to obtain the rotor assembly.

[0011] In one embodiment, step S2 includes: S21. A first mold is provided, the first mold including a first front mold and a first rear mold, the first rear mold having a first injection cavity for forming a first molding part; S22. Place the combined first insert and second insert into the first rear mold, so that the second insert is located in the first injection cavity; S23. The first front mold and the first rear mold are joined together to form the first molded part through the first injection molding.

[0012] In one embodiment, step S22 further includes: S221. A first insert and a second insert are provided, wherein the first insert is disposed in the first front mold and the second insert is disposed in the first rear mold; S222. The first insert is fitted onto the outer periphery of the connecting shaft of the first insert, and the second insert is inserted into the middle of the support platform of the first insert to position and fix the first insert and the second insert.

[0013] In one embodiment, step S2 further includes: S24. A first pressing block, a limiting block, and an elastic element are provided. The first pressing block is disposed corresponding to the edge area of ​​the first forming part. The limiting block is used to press the first pressing block. One end of the elastic element is connected to the first front mold, and the other end is connected to the first insert. During the mold opening process of the first mold, the first front mold moves along the axial direction of the first mold and causes the elastic element to deform so that the first insert keeps the rotor assembly in place. At the same time, the limiting block presses the first pressing block so that the first pressing block presses and limits the first forming part, keeps the first forming part in the first rear mold, and causes the first front mold body to detach from the rotor assembly before the first insert. As the first front mold continues to move, the first insert gradually detaches from the rotor assembly, completing the core pulling after the first injection molding.

[0014] In one embodiment, step S3 includes: S31. A second mold is provided, the second mold including a second front mold and a second rear mold, the second front mold having a second injection cavity for forming a second molding part, and the second rear mold having a third injection cavity for forming a first molding part; S32. After the first injection molding is completed, the first rear mold carrying the semi-finished product is rotated to a position corresponding to the second front mold. S33. The first rear mold and the second front mold are joined together to form a second molding part on the side of the first molding part away from the first insert by a second injection molding. S34. The second rear mold rotates to a position corresponding to the first front mold to perform the first injection molding of the next cycle.

[0015] In one embodiment, step S3 further includes: A second pressure block is provided, which is disposed in the second front mold and corresponds to the edge area of ​​the second forming part; During the mold opening process of the second mold, the second front mold moves along the axial direction of the second mold so that the body of the second front mold separates from the second forming part before the second pressure block; At the same time, the second pressure block presses and limits the second molding part so that the second molding part formed by the second injection molding is kept in the second mold and the gear core forming the transmission teeth is preferentially disengaged from the second molding part; As the second front mold continues to move, the second pressure block gradually releases its pressure on the second molding part, completing the core pulling after the second injection molding.

[0016] The present invention provides a rotor assembly in which at least a portion of the shaft portion is formed by a first insert, and a second insert is fitted around the outer periphery of the support platform of the first insert, so that the second insert and the first insert are coaxially arranged, thereby improving the coaxiality between the shaft portion and the gear portion and ensuring transmission accuracy. At the same time, the first molding portion covers the support platform and the second insert, so that the first insert, the second insert and the molding structure form a stable connection, thereby improving the overall structural strength of the rotor assembly. In addition, by forming the second molding portion on the side of the first molding portion away from the first insert, the gear area can be formed with a material suitable for transmission, thereby reducing material costs while ensuring gear accuracy and improving product consistency and mass production stability.

[0017] The present invention provides a method for manufacturing a rotor assembly. By pre-combining and positioning the first insert and the second insert, and then performing a first injection molding and a second injection molding in sequence, the shaft part and the gear part can be integrally formed, thereby reducing subsequent assembly processes and improving production efficiency. At the same time, by forming the first molding part and the second molding part through two injection moldings respectively, the structural strength and transmission performance can be taken into account, and the product dimensional accuracy and consistency can be improved. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the rotor assembly provided in a preferred embodiment of the present invention.

[0020] Figure 2 for Figure 1 A cross-sectional schematic diagram of the rotor assembly.

[0021] Figure 3 for Figure 1 A schematic diagram of the structure of the first forming part.

[0022] Figure 4 for Figure 1 A schematic diagram of the structure of the second forming part.

[0023] Figure 5 for Figure 1 A schematic diagram showing the first and second inserts placed inside the first injection cavity.

[0024] Figure 6 for Figure 1 A schematic diagram of the structure after the first molding part in the middle is injection molded.

[0025] Figure 7 for Figure 1 A schematic diagram of the structure of the rotor assembly after injection molding.

[0026] Figure 8 for Figure 5 A schematic diagram of the positioning structure of the first and second inserts.

[0027] Figure 9 This is a schematic diagram of the first mold core-pulling process provided in a preferred embodiment of the present invention.

[0028] Figure 10 This is a schematic diagram of the second mold core-pulling process provided in a preferred embodiment of the present invention.

[0029] Figure 11 This is a schematic diagram of the casting and molding of a rotor assembly according to a preferred embodiment of the present invention.

[0030] Figure label: 10. Rotating shaft; 20. Gear; 30. First mold; 40. Second mold; 50. Casting assembly; 11. First insert; 21. Second insert; 22. First molding part; 23. Second molding part; 111. Connecting shaft; 112. Support platform; 221. Engaging teeth; 231. Transmission teeth; 232. Fitting part; 31. First front mold; 32. First rear mold; 33. First injection cavity; 43. Third injection cavity; 41. Second front mold; 42. Second rear mold; 51. Inlet; 52. Outlet tube; 311. First insert; 312. Second insert; 313. Limiting block; 314. First pressure block; 315. Elastic element; 316. Movable cavity; 411. Second pressure block. Detailed Implementation

[0031] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0033] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of description and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0034] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0035] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0036] Please refer to Figures 1 to 2 This invention provides a rotor assembly, including a shaft portion 10 and a gear portion 20 connected to the shaft portion 10.

[0037] At least a portion of the shaft portion 10 is formed by a first insert 11, and the gear portion 20 includes a second insert 21, a first forming portion 22, and a second forming portion 23. The first insert 11 has two opposing ends extending axially along the rotor assembly, one end forming a connecting shaft 111 for connecting to a drive source, and the other end having a support platform 112. The connecting shaft 111 is used to connect to a motor, a reduction gear, or other power output device to receive power output from the drive source. The support platform 112 supports and positions the second insert 21 to ensure assembly accuracy between the gear portion 20 and the shaft portion 10.

[0038] The second insert 21 is fitted around the outer periphery of the support platform 112 and is coaxially arranged with the first insert 11. By arranging the second insert 21 and the first insert 11 coaxially, the coaxiality between the gear part 20 and the shaft part 10 can be improved, the wobble phenomenon during power transmission can be reduced, thereby improving the transmission accuracy and operational stability of the rotor assembly.

[0039] The first molding part 22 covers the support platform 112 and the second insert 21, so that the first insert 11 and the second insert 21 form a stable connection. The first molding part 22 can not only improve the connection strength between the shaft part 10 and the gear part 20, but also reduce the amount of metal material used while ensuring structural strength, thereby reducing the product manufacturing cost.

[0040] The second forming part 23 is connected to the side of the first forming part 22 away from the first insert 11, and the inner side of the second forming part 23 is provided with a transmission tooth 231. The transmission tooth 231 is used to mesh with an external transmission component to realize power transmission. By using the second forming part 23 to form the transmission tooth 231, the gear structure can be guaranteed to have high forming accuracy, and at the same time, it is convenient to select suitable materials according to different application requirements, so as to balance wear resistance, transmission performance and production cost.

[0041] like Figure 3-4 As shown, in this embodiment, a plurality of engagement teeth 221 are provided on the side where the first molding part 22 is connected to the second molding part 23. The plurality of engagement teeth 221 are distributed at intervals along the circumference of the first molding part 22. The second molding part 23 is provided with a plurality of fitting parts 232 corresponding one-to-one with the plurality of engagement teeth 221. Each engagement tooth 221 is fitted into the corresponding fitting part 232, so that the first molding part 22 and the second molding part 23 form a mechanical engagement connection.

[0042] Specifically, multiple engagement teeth 221 can be arranged in a ring array around the rotating shaft 10, so that the first forming part 22 and the second forming part 23 form multiple connection positions in the circumferential direction. When the second forming part 23 is formed, molten material flows into each interlocking part 232 and covers the corresponding engagement teeth 221, thereby forming a mutually interlocking connection structure between the two.

[0043] By incorporating the meshing teeth 221 and the fitting portion 232, a reliable mechanical locking structure can still be formed between the first molding portion 22 and the second molding portion 23, even if they are made of different materials. This improves the bonding strength between the first molding portion 22 and the second molding portion 23, reducing the risk of delamination, cracking, or detachment of the rotor assembly during power transmission. Simultaneously, the circumferential spacing of the multiple meshing teeth 221 ensures that torque is evenly transmitted to the second molding portion 23, improving the overall transmission reliability and service life of the rotor assembly.

[0044] In this embodiment, the number of meshing teeth 221 and mating portions 232 can be adjusted according to product size, transmission load, and material properties. For example, the number of meshing teeth 221 and mating portions 232 can be three, four, six, or more. Correspondingly, the meshing teeth 221 can be columnar, blocky, trapezoidal, dovetail-shaped, or other structural forms that are conducive to enhancing the bonding strength; this embodiment does not limit this.

[0045] Optionally, the first molding part 22 and the second molding part 23 are made of different materials. Specifically, the first molding part 22 is mainly used to form a support structure between the shaft part 10 and the gear part 20, so the first molding part 22 is formed of a high-strength material; the second molding part 23 is mainly used to form the transmission gear 231, so the second molding part 23 is formed of a material suitable for gear forming and transmission.

[0046] In this embodiment, both the first insert 11 and the second insert 21 are metal parts. The first insert 11 forms the main load-bearing structure of the shaft portion 10, and the second insert 21 forms the support structure of the gear portion 20. By setting metal parts to form the skeleton structure of the rotor assembly, the structural strength and dimensional stability of the rotor assembly can be improved; at the same time, by covering the outer periphery of the metal parts with molded parts, the amount of metal material used can be reduced, the product manufacturing cost can be reduced, and it is beneficial to realize the lightweight design of the rotor assembly.

[0047] In this embodiment, the first molding part 22 is molded using glass fiber reinforced polyamide material (PA+GF), and the second molding part 23 is molded using polyamide material (PA).

[0048] Among them, glass fiber reinforced polyamide material has high mechanical strength, rigidity, and dimensional stability. Therefore, the first molding part 22 is formed of glass fiber reinforced polyamide material to improve the support capacity of the first molding part 22 for the first insert 11 and the second insert 21, and reduce the risk of deformation during long-term use. Polyamide material has good flowability, wear resistance, and molding performance. Therefore, the second molding part 23 is formed of polyamide material to ensure that the transmission gear 231 has high molding accuracy and surface quality. At the same time, polyamide material also has good wear resistance and self-lubricating properties, which helps to reduce wear during gear meshing and improve the service life of the rotor assembly.

[0049] This invention also provides a method for preparing a rotor assembly, used to prepare the rotor assembly in the above embodiments, the method comprising: S1. A first insert 11 and a second insert 21 are provided, and the second insert 21 is fitted onto the outer periphery of the support platform 112 of the first insert 11, so that the second insert 21 and the first insert 11 are coaxially arranged. The first insert 11 forms the main load-bearing structure of the shaft portion 10, and the second insert 21 forms the support structure of the gear portion 20. By pre-positioning the first insert 11 and the second insert 21, the coaxiality between the shaft portion 10 and the gear portion 20 during subsequent molding can be ensured, improving the dimensional accuracy and transmission accuracy of the product.

[0050] S2. The combined first insert 11 and second insert 21 are injection molded for the first time to form a first molding portion 22 covering the support platform 112 and the second insert 21. After the first molding portion 22 is formed, the first insert 11, the second insert 21, and the first molding portion 22 constitute a stable semi-finished product structure. Since the first molding portion 22 simultaneously covers the support platform 112 and the second insert 21, it can enhance the connection strength between the first insert 11 and the second insert 21 and improve the overall stability of the rotor assembly structure.

[0051] S3. After the first injection molding is completed, the semi-finished product is subjected to a second injection molding to form a second molding part 23 on the side of the first molding part 22 away from the first insert 11. During the molding process of the second molding part 23, transmission teeth 231 are formed, thereby obtaining a complete rotor assembly. By forming the first molding part 22 and the second molding part 23 by two injection molding processes, it is possible not only to select materials with different properties according to different functional areas, but also to take into account structural strength, dimensional stability, and gear transmission performance.

[0052] like Figure 5 As shown, in this embodiment, the first injection molding is completed using the first mold 30, that is, step S2 includes: S21. A first mold 30 is provided, which includes a first front mold 31 and a first rear mold 32. The first rear mold 32 has a first injection cavity 33 for forming a first molding part 22. The shape of the first injection cavity 33 is adapted to the shape of the first molding part 22, and is used to form the first molding part 22 covering the support platform 112 and the second insert 21 during the injection molding process.

[0053] S22. Before injection molding, the combined first insert 11 and second insert 21 are placed in the first rear mold 32, and the second insert 21 is positioned at the corresponding position in the first injection cavity 33. Subsequently, the first front mold 31 and the first rear mold 32 are closed to form a closed injection space in the first injection cavity 33.

[0054] S23. After mold closing, molten plastic is injected into the first injection cavity 33. The molten plastic flows and covers at least part of the outer surface of the support platform 112 and the second insert 21, and after cooling and solidification, forms the first molding part 22. After the first molding part 22 is formed, the first insert 11, the second insert 21 and the first molding part 22 form a stable connected semi-finished product structure.

[0055] By using the first mold 30 to complete the first injection molding, the first molding part 22 can form an integrated structure with the first insert 11 and the second insert 21, thereby improving the connection strength and structural stability between the two inserts. At the same time, since the first insert 11 and the second insert 21 have been positioned before injection molding, the first molding part 22 can maintain their relative positional relationship during the molding process, which is beneficial to ensuring the coaxiality between the shaft part 10 and the gear part 20, and provides a precise positioning basis for the subsequent second injection molding and the molding of the transmission gear 231.

[0056] like Figure 8 As shown, to further improve the positioning accuracy of the first insert 11 and the second insert 21 during the first injection molding process, in this embodiment, step S22 further includes: S221. A first insert 311 and a second insert 312 are provided, wherein the first insert 311 is disposed on the first front mold 31 and the second insert 312 is disposed on the first rear mold 32.

[0057] S222. After the combined first insert 11 and second insert 21 are placed into the first rear mold 32, the first insert 311 is sleeved on the outer periphery of the connecting shaft 111, and the second insert 312 is inserted into the middle of the support platform 112 to position and fix the first insert 11 and the second insert 21.

[0058] Specifically, the first insert 311 cooperates with the connecting shaft 111, limiting the outer periphery of the connecting shaft 111 to maintain a stable position of the first insert 11 in the radial and axial directions. The second insert 312 cooperates with the support platform 112, supporting and positioning the support platform 112 to limit the displacement of the first insert 11 and the second insert 21 during the injection molding process.

[0059] When the first front mold 31 and the first rear mold 32 are closed, the first insert 311 and the second insert 312 support and position the first insert 11 from both sides, thereby forming a double-end positioning structure. Through double-end positioning, not only can the positioning accuracy of the first insert 11 itself be improved, but also a stable coaxial relationship between the second insert 21 and the first insert 11 can be ensured.

[0060] Subsequently, the first injection molding is performed, and molten plastic enters the first injection cavity 33 and covers the support platform 112 and the second insert 21 to form the first molded part 22. Under the action of injection pressure, the first insert 311 and the second insert 312 continuously position and support the first insert 11 and the second insert 21, thereby preventing the inserts from shifting or tilting, which helps to improve the molding accuracy of the first molded part 22 and the coaxiality between the rotating shaft part 10 and the gear part 20.

[0061] like Figure 9 As shown, in this embodiment, step S2 further includes: S24. A first pressing block 314, a limiting block 313, and an elastic element 315 are provided. The first pressing block 314 is disposed corresponding to the edge region of the first molding part 22. The limiting block 313 is used to limit and hold the first pressing block 314. A movable cavity 316 for accommodating the limiting block 313 is provided in the first front mold 31. The limiting block 313 is movably disposed within the movable cavity 316. The dimension of the movable cavity 316 in the axial direction of the second insert 312 is larger than the thickness of the limiting block 313. One end of the elastic element 315 is connected to the first front mold 31, and the other end is connected to the first insert 311. The elastic element 315 can be a spring, an elastic colloid, or other structures with elastic recovery capability; this embodiment does not limit this.

[0062] After the first injection molding is completed and cooled, the first front mold 31 and the first rear mold 32 begin to open. In the initial stage of mold opening, the first front mold 31 moves along the axial direction of the first mold 30, causing the elastic element 315 to undergo tensile deformation. Due to the connecting effect of the elastic element 315, the first insert 311 maintains its positioning state on the rotor assembly in the initial stage, thereby preventing the rotor assembly from shaking or shifting during the mold opening process.

[0063] Meanwhile, as the first mold 30 moves relative to the limiting block 313, the movable cavity 313 continues to press the first pressing block 314, keeping it in contact with the edge region of the first forming part 22. With the pressing action of the first pressing block 314, the first forming part 22 remains on the side of the first rear mold 32, thereby preventing the rotor assembly from moving with the first front mold 31.

[0064] As the mold opening process continues, the main body of the first front mold 31 gradually detaches from the rotor assembly, while the first insert 311 is delayed in exiting under the action of the elastic element 315. Since the rotor assembly is always held and limited by the first pressure block 314, the first insert 311 can be gradually pulled out relative to the product, thereby completing the sequential demolding of the corresponding molding areas.

[0065] After the first insert 311 is completely detached, the semi-finished product formed by the first injection molding remains in the first rear mold 32 and then proceeds to the next process. By setting the first pressure block 314, the limiting block 313, and the elastic element 315 to form a sequential core-pulling structure, it is possible to ensure that the product remains stably positioned during the core-pulling process, avoiding displacement, deformation, or damage to the product due to core-pulling resistance, thereby improving the demolding stability and product yield after the first injection molding.

[0066] Furthermore, multiple first pressing blocks 314 can be arranged around the first forming part 22, and the multiple first pressing blocks 314 are spaced apart around the first forming part 22 to improve the uniformity of force on the product during the core pulling process.

[0067] Optionally, the limiting block 313 is movably connected to the first front mold 31. During the mold opening process, the main body of the first front mold 31 first separates from the rotor assembly. After the first front mold 31 continues to move, the limiting block 313 gradually releases its pressure on the first pressing block 314, thereby extending the pressing time of the first pressing block 314 on the first forming part 22 and further ensuring the stability of the core pulling process.

[0068] like Figure 6-7 As shown, in this embodiment, the second injection molding is completed using the second mold 40, that is, step S3 further includes: S31. A second mold 40 is provided, which includes a second front mold 41 and a second rear mold 42. The second front mold 41 is provided with a second injection cavity for forming a second molding portion 23, and the second rear mold 42 is provided with a third injection cavity 43 for forming a first molding portion 22. The second injection cavity is used to form the second molding portion 23 and the transmission gear 231, and the third injection cavity 43 is used to form the first molding portion 22.

[0069] S32. After the first injection molding is completed, the first rear mold 32 carrying the semi-finished product is rotated to the position corresponding to the second front mold 41.

[0070] S33. Subsequently, the first rear mold 32 and the second front mold 41 are closed, and a second molding part 23 is formed on the side of the first molding part 22 away from the first insert 11 by a second injection molding. When the second molding part 23 is formed, the molten plastic fills the second injection cavity and forms the transmission teeth 231, thereby obtaining a complete rotor assembly.

[0071] S34. Simultaneously, the second rear mold 42 rotates to a position corresponding to the first front mold 31. An operator or automatic feeding mechanism places the combined first insert 11 and second insert 21 into the second rear mold 42, positioning the second insert 21 in the position corresponding to the third injection cavity 43. Subsequently, the first front mold 31 and the second rear mold 42 close, and the first injection of the next cycle is performed to form a new first molded part 22.

[0072] After the second injection molding is completed, the first rear mold 32 and the second rear mold 42 continue to rotate and exchange positions. Specifically, the first rear mold 32, which had just completed the second injection molding, rotates to the corresponding position on the first front mold 31 for product demolding; the second rear mold 42, which had just completed the first injection molding, rotates to the corresponding position on the second front mold 41 for the second injection molding. This process is then repeated, achieving a cyclical switching between the first and second injection molding positions.

[0073] By setting up a production method where the first rear mold 32 and the second rear mold 42 rotate alternately, the first and second injection molding processes can be performed synchronously, thereby reducing equipment waiting time and improving equipment utilization and production efficiency. Simultaneously, the semi-finished product maintains a stable position throughout the two injection molding processes, which helps ensure the positional accuracy between the first molding part 22 and the second molding part 23, improving the dimensional consistency and transmission accuracy of the rotor assembly. Furthermore, this process enables continuous and automated production of rotor assemblies, making it suitable for mass production scenarios.

[0074] Furthermore, the cavity structure corresponding to the transmission gear 231 in the second injection cavity is formed using high-precision machining. Since the transmission gear 231 directly participates in power transmission, its tooth profile accuracy will directly affect the transmission efficiency, meshing stability, and service life of the rotor assembly. Therefore, the dimensional accuracy of the gear cavity area corresponding to the second injection cavity is higher than that of the first injection cavity 33 and the third injection cavity 4343.

[0075] When the machining accuracy of the gear cavity area corresponding to the second injection cavity is insufficient, it can easily lead to problems such as tooth profile deviation, tooth pitch error, or uneven meshing in the transmission gear 231, thereby affecting the transmission stability of the rotor assembly. Therefore, in this embodiment, the machining dimensional deviation of the gear cavity area corresponding to the second injection cavity is controlled within ±0.01mm to ensure the tooth profile accuracy and dimensional consistency of the transmission gear 231. By performing high-precision machining on the second injection cavity, the dimensional error of the transmission gear 231 during the molding process can be reduced, the gear meshing accuracy can be improved, and thus the transmission performance of the rotor assembly can be guaranteed.

[0076] In this embodiment, during the first injection molding of the first molding part 22, a plurality of interlocking teeth 221 are simultaneously formed on the side of the first molding part 22 facing the second molding part 23. The plurality of interlocking teeth 221 are distributed circumferentially around the first molding part 22. The plurality of interlocking teeth 221 may be columnar, blocky, trapezoidal, dovetail-shaped, or other structural forms that are conducive to enhancing the connection strength. This embodiment does not limit this.

[0077] During the second injection molding, molten plastic flows into the area between each engagement tooth 221, forming multiple interlocking portions 232 at corresponding positions. Each interlocking portion 232 cooperates with the corresponding engagement tooth 221, so that the second molding portion 23 and the first molding portion 22 form a mechanical locking structure.

[0078] In one embodiment, the engagement teeth 221 are protruding structures protruding from the surface of the first molding part 22; during the second injection molding process, the molten plastic covers each engagement tooth 221 and forms a corresponding mating part 232 after cooling and solidification, thereby enabling the first molding part 22 and the second molding part 23 to form a limiting effect in the axial direction, radial direction and circumferential direction.

[0079] By pre-forming the interlocking teeth 221 during the first injection molding process and forming the corresponding mating portions 232 during the second injection molding process, a reliable mechanical interlocking connection can be formed between the first molding portion 22 and the second molding portion 23. Even if the first molding portion 22 and the second molding portion 23 are formed of different materials, they can still maintain a high bonding strength, thereby reducing the risk of cracking, delamination, or separation during long-term use.

[0080] Furthermore, the multiple meshing teeth 221, when distributed circumferentially, enable the torque to be uniformly transmitted from the first forming part 22 to the second forming part 23, avoiding local stress concentration and improving the overall transmission reliability and service life of the rotor assembly.

[0081] like Figure 10 As shown, in this embodiment, step S3 further includes: A second pressure block 411 is provided and installed inside the second front mold 41, corresponding to the edge area of ​​the second molding part 23. After the second injection molding is completed and cooled, the second front mold 41 and the first rear mold 32 begin to open. In the initial stage of mold opening, the second front mold 41 moves along the axial direction of the second mold 40. Since the second pressure block 411 is movably disposed inside the second front mold 41, during the movement of the main body of the second front mold 41, the main body of the second front mold 41 gradually separates from the pressure block 411, while the second pressure block 411 remains in contact with the second molding part 23 and continues to press and limit the second molding part 23.

[0082] Under the pressure of the second pressure block 411, the rotor assembly remains on the side of the first rear mold 32, thereby preventing the product from moving with the second front mold 41. At the same time, the gear core forming the transmission teeth 231 gradually separates from the second forming part 23. Since the second pressure block 411 continuously limits and holds the product, it can ensure that the product remains stable during the removal of the gear core, avoiding product displacement, warping, or damage.

[0083] As the mold opening process continues, the main body of the second front mold 41 gradually moves away from the product, and the gear core forming the transmission teeth 231 preferentially detaches from the second molding part 23. After the gear core has completely detached, the second pressure block 411 is removed to release the pressure on the second molding part 23, thereby completing the core pulling process after the second injection molding.

[0084] In this embodiment, a holding structure is formed by setting a second pressure block 411, which ensures that the product remains stably positioned during the extraction of the gear core. Especially when the transmission gear 231 has high precision requirements, or when the tooth surface does not have a draft angle or only a small draft angle is set, the second pressure block 411 can still effectively prevent the product from moving with the core, thereby ensuring the contour accuracy and surface quality of the transmission gear 231, and improving the product demolding stability and molding yield.

[0085] Furthermore, multiple second pressing blocks 411 can be arranged circumferentially along the second molding section 23, with the multiple second pressing blocks 411 spaced apart around the periphery of the second molding section 23 to ensure that the holding force is applied evenly to the product. Optionally, the second pressing blocks 411 can be movably installed in the second front mold 41 through elastic components, guide structures, or limiting structures, thereby realizing relative movement between the second pressing blocks 411 and the main body of the second front mold 41 to meet the requirements of sequential core pulling.

[0086] like Figure 11 As shown, in this embodiment, steps S2 and S3 further include providing a casting component 50.

[0087] The casting assembly 50 is used to deliver molten plastic into the first injection cavity 33, the second injection cavity and the third injection cavity 43 to complete the first injection and the second injection.

[0088] Specifically, the casting assembly 50 includes an inlet 51 and a plurality of outlet pipes 52 connected to the inlet 51. The inlet 51 is used to connect to the injection molding equipment to receive molten plastic conveyed by the injection molding equipment; the plurality of outlet pipes 52 are respectively connected to the corresponding injection cavity to convey the molten plastic to the corresponding injection area.

[0089] When the number of ejector tubes 52 is too small, the molten plastic needs to go through a longer flow path to fill each injection cavity, which can easily lead to problems such as increased flow resistance, increased pressure loss and local insufficient filling, thereby affecting the molding accuracy of the first molding part 22 and the second molding part 23. At the same time, due to the difference in the filling time of each area, it can also easily lead to uneven product shrinkage, warping deformation or decreased dimensional stability.

[0090] However, when there are too many ejector tubes 52, although the flow distance of molten plastic can be shortened, the complexity of the gating system will be increased, making the mold structure more complicated. At the same time, too many injection points can easily cause multiple streams of molten plastic to merge in the mold cavity, forming weld lines, which will affect the structural strength and appearance quality of the product, and increase material waste and production costs.

[0091] Based on the above considerations, after multiple experimental verifications, it was found that using six glue outlet pipes 52 for glue supply can achieve a good balance between mold filling uniformity, molding quality, mold structure complexity, and production cost. Therefore, this embodiment preferably uses six glue outlet pipes 52 to achieve stable molding and efficient production of the rotor assembly.

[0092] Furthermore, the six ejector tubes 52 are evenly distributed to ensure that the molten plastic can enter the corresponding injection cavity uniformly, thereby reducing pressure loss during the flow process and improving mold filling uniformity. By setting multiple ejector tubes 52, the flow distance of the molten plastic can be shortened, reducing problems such as temperature drop, uneven flow, or insufficient filling caused by excessive flow distance.

[0093] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A rotor assembly characterized by, The assembly includes a rotating shaft and a gear connected to the rotating shaft; at least a portion of the rotating shaft is formed by a first insert, and the gear includes a second insert, a first molded portion, and a second molded portion; the first insert has two opposite ends extending axially along the rotor assembly, one end of which forms a connecting shaft for connecting to a drive source, and the other end is provided with a support platform for supporting the second insert; the second insert is sleeved on the outer periphery of the support platform and coaxially arranged with the first insert, the first molded portion covers the support platform and the second insert, the second molded portion is connected to the side of the first molded portion away from the first insert, and the inner side of the second molded portion is provided with transmission teeth.

2. The rotor assembly as claimed in claim 1, characterized in that, The first molding part is provided with a plurality of biting teeth on the side connected to the second molding part. The plurality of biting teeth are arranged at intervals along the circumference of the first molding part. The second molding part is provided with a plurality of fitting parts corresponding to the plurality of biting teeth. Each biting tooth is fitted into the corresponding fitting part.

3. The rotor assembly of claim 2, wherein The first molding part and the second molding part are made of different materials.

4. The rotor assembly of claim 3, wherein The first molding part is made of glass fiber reinforced polyamide material, and the second molding part is made of polyamide material.

5. A method of making a rotor assembly, characterized by, The method for preparing the rotor assembly as described in any one of claims 1-4 comprises: S1. Provide a first insert and a second insert, and fit the second insert onto the outer periphery of the support platform of the first insert so that the second insert is coaxially arranged with the first insert; S2. Perform a first injection molding on the first insert and the second insert to form a first molded part covering the support platform and the second insert; S3. Perform a second injection molding on the semi-finished product after the first injection molding to form a second molding part on the side of the first molding part away from the first insert, so as to obtain the rotor assembly.

6. The production method according to claim 5, wherein Step S2 includes: S21. A first mold is provided, the first mold including a first front mold and a first rear mold, the first rear mold having a first injection cavity for forming a first molding part; S22. Place the combined first insert and second insert into the first rear mold, so that the second insert is located in the first injection cavity; S23. The first front mold and the first rear mold are joined together to form the first molded part through the first injection molding.

7. The production method according to claim 6, wherein Step S22 further includes: S221. A first insert and a second insert are provided, wherein the first insert is disposed in the first front mold and the second insert is disposed in the first rear mold; S222. The first insert is fitted onto the outer periphery of the connecting shaft of the first insert, and the second insert is inserted into the middle of the support platform of the first insert to position and fix the first insert and the second insert.

8. The production method according to claim 7, wherein Step S2 further includes: S24. A first pressing block, a limiting block, and an elastic element are provided. The first pressing block is disposed corresponding to the edge area of ​​the first forming part. The limiting block is used to press the first pressing block. One end of the elastic element is connected to the first front mold, and the other end is connected to the first insert. During the mold opening process of the first mold, the first front mold moves along the axial direction of the first mold and causes the elastic element to deform so that the first insert keeps the rotor assembly in place. At the same time, the limiting block presses the first pressing block so that the first pressing block presses and limits the first forming part, keeps the first forming part in the first rear mold, and causes the first front mold body to detach from the rotor assembly before the first insert. As the first front mold continues to move, the first insert gradually detaches from the rotor assembly, completing the core pulling after the first injection molding.

9. The production method according to claim 6, wherein Step S3 includes: S31. A second mold is provided, the second mold including a second front mold and a second rear mold, the second front mold having a second injection cavity for forming a second molding part, and the second rear mold having a third injection cavity for forming a first molding part; S32. After the first injection molding is completed, the first rear mold carrying the semi-finished product is rotated to a position corresponding to the second front mold. S33. The first rear mold and the second front mold are joined together to form a second molding part on the side of the first molding part away from the first insert by a second injection molding. S34. The second rear mold rotates to a position corresponding to the first front mold to perform the first injection molding of the next cycle.

10. The preparation method according to claim 9, characterized in that, Step S3 further includes: A second pressure block is provided, which is disposed in the second front mold and corresponds to the edge area of ​​the second forming part; During the mold opening process of the second mold, the second front mold moves along the axial direction of the second mold so that the body of the second front mold separates from the second forming part before the second pressure block; At the same time, the second pressure block presses and limits the second molding part so that the second molding part formed by the second injection molding is kept in the second mold and the gear core forming the transmission teeth is preferentially disengaged from the second molding part; As the second front mold continues to move, the second pressure block gradually releases its pressure on the second molding part, completing the core pulling after the second injection molding.

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