Multi-cavity cast-aluminum rotor die-casting mold and motor rotor

Abstract

The invention relates to the technical field of cast-aluminum rotors, in particular to a multi-cavity cast-aluminum rotor die-casting die and a motor rotor, the multi-cavity cast-aluminum rotor die-casting die comprises an upper die, a middle die and a lower die, and the middle die is provided with a plurality of main cavities; an upper end ring groove corresponding to the main cavity is formed in the upper die, and a dummy shaft hole is formed in the center of the upper end ring groove; a lower end ring groove corresponding to the main cavity is formed in the lower die, and a positioning groove is formed in the center of the lower end ring groove; the rotor iron core is placed in the main cavity, and the main cavity is a cylindrical hole and is in clearance fit with the rotor iron core; the dummy shaft assembly is placed in the dummy shaft hole, through transverse extrusion of the dummy shaft assembly, the quality of the shaft hole of the cast-aluminum rotor is improved, molten aluminum is prevented from being extruded into gaps between rotor iron core punching sheets, transverse current is reduced, and additional loss of the motor is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of cast aluminum rotors, in particular to a multi-cavity cast aluminum rotor die-casting mold and a motor rotor. Background Art

[0002] The cast aluminum rotor is a key component in the asynchronous motor. Its manufacturing process mainly includes mold design, rotor core preparation, aluminum melting and pouring, cooling and demoulding, post-processing and quality inspection. First, the mold is made according to the rotor design drawing. The mold is usually made of high-temperature resistant materials to ensure that it can withstand the impact of high-temperature aluminum liquid and maintain precise dimensions. Then the silicon steel sheets are stacked into the rotor core. The stacking coefficient and axial length of the rotor core need to be strictly controlled to ensure its electromagnetic performance. After the rotor core is stacked, it is placed in the preheated mold and prepared for aluminum casting. The aluminum melting process is to heat pure aluminum or aluminum alloy to a molten state and remove impurities and oxides to ensure the purity of the aluminum liquid. During pouring, the molten aluminum liquid is injected into the mold by centrifugal casting or pressure casting to fill the groove and end ring of the rotor core. Centrifugal casting uses centrifugal force to evenly distribute the aluminum liquid, while pressure casting uses external pressure to ensure that the aluminum liquid fully fills every corner of the mold. After pouring, the rotor enters the cooling stage and is demoulded after the aluminum liquid solidifies. After demoulding, the rotor needs to be deburred, polished and surface treated to remove excess aluminum chips and burrs to ensure that the appearance and size of the rotor meet the requirements. Finally, dynamic balancing test and electrical performance test are performed to ensure that the balance and electromagnetic performance of the rotor meet the standards when running at high speed. The entire manufacturing process requires high precision and high consistency to ensure that the performance and reliability of the cast aluminum rotor meet the working requirements of the motor.

[0003] Common aluminum casting methods include low-pressure aluminum casting, centrifugal aluminum casting, and pressure aluminum casting. Among these three aluminum casting methods, the additional loss of pressure cast aluminum rotor motor is the largest. This is because the strong pressure during die casting makes the cage bars and the iron core contact very closely, so that the aluminum liquid squeezes into the gaps between the punching sheets, the lateral current increases, and the additional loss of the motor increases greatly. In addition, due to the uneven processing quality of the punching sheet's shaft hole, after aluminum casting, the shaft hole quality may be affected due to the misalignment of the punching sheet's shaft hole, making the subsequent assembly of the true shaft and the cast aluminum rotor difficult. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a multi-cavity cast aluminum rotor die-casting mold and a motor rotor. A dummy shaft assembly is arranged in the cast aluminum rotor die-casting mold to apply lateral extrusion to the rotor core, thereby improving the quality of the axial hole of the cast aluminum rotor. The protrusions on the rotor core can also prevent aluminum liquid from being squeezed into the gaps between the rotor core punchings, thereby reducing the lateral current and the additional loss of the motor.

[0005] To achieve the above object, the present invention provides the following technical solutions: A multi-cavity cast aluminum rotor die-casting mold, comprising an upper mold, a middle mold and a lower mold, wherein the middle mold is provided with a plurality of main cavities; the upper mold is provided with an upper end ring groove corresponding to the main cavity, and a dummy shaft hole is provided at the center of the upper end ring groove; the lower mold is provided with a lower end ring groove corresponding to the main cavity, and a positioning groove is provided at the center of the lower end ring groove; the rotor core is placed in the main cavity, and the main cavity is a cylindrical hole and is gap-matched with the rotor core; the dummy shaft assembly is placed in the dummy shaft hole, and the dummy shaft assembly passes through the rotating shaft hole in the middle of the rotor core, and the lower end of the dummy shaft assembly is matched with the positioning groove; the extrusion assembly on the dummy shaft assembly acts on the side of the rotating shaft hole to realize the positioning of the punching sheets of the rotor core, and at the same time closes the gap formed between the punching sheets.

[0006] Furthermore, the middle die is provided with a plurality of guide post holes; the upper die and the lower die are respectively provided with upper guide posts and lower guide posts cooperating with the guide post holes; the lower die is also provided with a plurality of injection ports connected with the lower end ring groove; the lower end of the lower die is provided with a positioning boss cooperating with the die-casting cylinder.

[0007] Furthermore, the dummy shaft assembly includes a shaft cylinder positioned and matched with the upper mold and the lower mold; the drive shaft is slidably arranged in the middle of the shaft cylinder; the extrusion assembly includes a first extrusion part and a second extrusion part which are arranged in different directions; the drive shaft is transmission-connected with the first extrusion part and the second extrusion part; the first extrusion part includes a connecting rod structure, and the second extrusion part includes a wedge block structure; a positioning block is arranged on the shaft cylinder to limit the moving direction of the drive shaft.

[0008] Furthermore, the upper end of the shaft cylinder is provided with an upper positioning portion that cooperates with the false shaft hole of the upper mold; the lower end of the shaft cylinder is provided with a lower positioning portion that cooperates with the positioning groove of the lower mold; a limiting groove is provided on the driving shaft, and the positioning blocks relatively arranged on the shaft cylinder are clamped with the limiting groove; one end of the driving shaft extending out of the shaft cylinder is connected to the external actuating mechanism, and the other end of the driving shaft is provided with a first hinge shaft and a first wedge block; the first hinge shaft is connected to the connecting rod structure of the first extrusion part; the first wedge block is connected to the wedge block structure of the second extrusion part.

[0009] Furthermore, the connecting rod structure of the first extrusion part includes a driving rod and a supporting rod; one end of the driving rod is hinged to the first hinge shaft of the driving shaft, and the other end is hinged to the middle part of the supporting rod; one end of the supporting rod is hinged to the second hinge shaft of the shaft tube, and the other end is transmission connected to the extrusion block.

[0010] Furthermore, the extrusion block has an arc-shaped end face adapted to the shaft hole of the rotor core; the other side of the arc-shaped end face of the extrusion block is provided with a convex ridge, and a plurality of waist-shaped holes are provided on the convex ridge; a sliding pin is provided at the end of the support rod, and the sliding pin slides with the waist-shaped hole; a rotating shaft connected to the driving rod is provided in the middle of the support rod.

[0011] Furthermore, there are two first wedge blocks, which are symmetrically arranged on both sides of the drive shaft; the wedge block structure of the second extrusion part includes a second wedge block and a guide block; the second extrusion part has an arc-shaped end face adapted to the shaft hole of the rotor core, and the second wedge block is arranged on the other side of the arc-shaped end face of the second extrusion part; the second wedge block abuts against the first wedge block of the drive shaft; guide parts are arranged on both sides of the guide block, and the guide parts are slidably arranged in the guide groove of the shaft cylinder.

[0012] The motor rotor of the present invention is made of the above-mentioned cast aluminum rotor die-casting mold, and the rotor core is pressed by multiple punching sheets; a shaft hole is provided in the middle of the punching sheet, and multiple guide bar grooves are opened in the circumferential direction of the punching sheet; the outer circular end surface of the punching sheet of the rotor core is gap-matched and positioned with the main cavity of the middle mold; after the mold is closed, the extrusion component of the dummy shaft component abuts against the shaft hole of the punching sheet of the rotor core to form an inner circular end surface.

[0013] Furthermore, a second protrusion is arranged around the lower opening of the shaft hole of the punch; a first protrusion is arranged around the lower opening of the guide bar groove; the inclined end surface formed by the first protrusion and the hole wall of the guide bar groove, and the inclined end surface formed by the second protrusion and the hole wall of the shaft hole, both have an angle with the vertical direction.

[0014] Furthermore, after the mold is closed, the upper die pressing platform of the upper mold presses the upper part of the rotor core; the lower die pressing platform of the lower mold abuts the lower part of the rotor core; the extrusion assembly of the dummy shaft assembly laterally extrudes the second protrusion of the rotor core shaft hole, and cooperates with the aluminum liquid delivered by the die-casting machine to laterally extrudes the first protrusion of the rotor core guide groove, so that the gap between the punching sheets of the rotor core tends to close.

[0015] Compared with the prior art, the present invention provides a multi-cavity cast aluminum rotor die-casting mold and a motor rotor, which have the following beneficial effects: the dummy shaft assembly arranged in the cast aluminum rotor die-casting mold can apply lateral extrusion to the shaft hole of the rotor core, so that the shaft hole of the cast aluminum rotor after die-casting has higher straightness, and the quality of the shaft hole of the cast aluminum rotor is improved to facilitate the subsequent assembly with the real shaft of the motor; at the same time, the punching sheets of the rotor core are provided with vertically extending protrusions, and the rotor core can make the gaps between the punching sheets have a tendency to close after being lateral extruded by the dummy shaft assembly, thereby reducing / preventing the aluminum liquid from being squeezed into the gaps between the punching sheets, reducing the lateral current of the motor, and reducing the additional loss of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the multi-cavity cast aluminum rotor die-casting mold of the present invention; Figure 2 An exploded view of the multi-cavity cast aluminum rotor die-casting mold of the present invention; Figure 3It is a structural schematic diagram of the upper mold of the present invention; Figure 4 It is a structural schematic diagram of the lower mold of the present invention; Figure 5 is a cross-sectional view of the lower mold of the present invention; Figure 6 is a cross-sectional view of a multi-cavity cast aluminum rotor die-casting mold of the present invention; Figure 7 is a schematic diagram of the initial state of the dummy shaft assembly of the present invention; Figure 8 It is a schematic diagram of the extrusion state of the dummy shaft assembly of the present invention; Fig. 9 is a cross-sectional view of the dummy shaft assembly of the present invention in another direction; Fig.10 An exploded view of a dummy shaft assembly of the present invention; Fig.11 is a cross-sectional view of a dummy shaft assembly of the present invention; Fig.12 It is a schematic structural diagram of the rotor core of the present invention; Fig.13 It is a structural schematic diagram of the punching sheet of the present invention; Fig.14 is a cross-sectional view of a punching sheet of the present invention; Fig.15 is a cross-sectional view of a rotor core of the present invention; In the figure: Dummy shaft assembly 1, driving shaft 11, first hinge shaft 111, first wedge block 112, limiting groove 113, shaft cylinder 12, upper positioning portion 121, lower positioning portion 122, second hinge shaft 123, guide groove 124, extrusion assembly 13, positioning block 14, first extrusion portion 15, driving rod 151, support rod 152, sliding pin 1521, rotating shaft 1522, extrusion block 153, waist-shaped hole 1531, second extrusion portion 16, second wedge block 161, guide block 162; Upper die 2, dummy shaft hole 21, upper die pressing platform 211, upper guide column 22, upper end ring groove 23; Middle mold 3, main cavity 31, guide post hole 32; Lower die 4, lower end annular groove 41, positioning groove 42, lower die pressing platform 421, lower guide pillar 43, injection port 44, positioning boss 45; The rotor core 5 , the punching sheet 51 , the guide bar groove 511 , the shaft hole 512 , the first protrusion 501 , the second protrusion 502 , and the gap 50 . DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] According to the following Figure 1-Figure 15 The present invention is described in detail. A multi-cavity cast aluminum rotor die-casting mold of the present invention includes an upper mold 2, a middle mold 3, and a lower mold 4, wherein the middle mold 3 is provided with a plurality of main cavities 31; the upper mold 2 is provided with an upper end ring groove 23 corresponding to the main cavity 31, and a dummy shaft hole 21 is provided at the center of the upper end ring groove 23; the lower mold 4 is provided with a lower end ring groove 41 corresponding to the main cavity 31, and a positioning groove 42 is provided at the center of the lower end ring groove 41; the rotor core 5 is placed in the main cavity 31, and the main cavity 31 is a cylindrical hole and is gap-matched with the rotor core 5; the dummy shaft assembly 1 is placed in the dummy shaft hole 21, and the dummy shaft assembly 1 passes through the shaft hole 512 in the middle of the rotor core 5, and the lower end of the dummy shaft assembly 1 is matched with the positioning groove 42; the extrusion assembly 13 on the dummy shaft assembly 1 acts on the side of the shaft hole 512 to realize the positioning of the punching sheets 51 of the rotor core 5, and at the same time closes the gap 50 formed between the punching sheets 51.

[0019] Specifically, when die-casting a cast aluminum rotor, strong pressure may squeeze the aluminum liquid into the gap 50 between the punching plates 51, causing the lateral current of the motor to increase and thus increasing the additional loss. At the same time, due to factors such as fluctuations in the hole processing quality of the punching plates 51, the shaft hole 512 of the punching plates 51 cannot be aligned during the die-casting process, thereby reducing the quality of the shaft hole of the cast aluminum rotor and affecting the fit between the shaft hole of the cast aluminum rotor and the true shaft. The main cavity 31 on the middle mold 3 of the present invention positions the outer cylindrical end surface of the punching plates 51 of the rotor core 5 through clearance fit. After the dummy shaft assembly 1 passes through the dummy shaft hole 21 and the shaft hole 512 of the rotor core 5 from top to bottom and is placed in the positioning groove 42, the extrusion assembly 13 of the dummy shaft assembly 1 can be laterally (such as Figure 6 The end surface of the dummy shaft assembly 1 is protruded in the transverse direction, and a transverse extrusion force G is applied to the end surface of the rotating shaft hole 512 through the extrusion assembly 13, see Fig.15 , which can realize the positioning of the punching sheets 51 of the rotor core 5 , and at the same time cooperate with the protrusion structure on the punching sheets 51 to close the gaps 50 between the punching sheets 51 , thereby reducing the aluminum liquid from being squeezed into the gaps 50 .

[0020] The middle die 3 is provided with a plurality of guide post holes 32; the upper die 2 and the lower die 4 are respectively provided with upper guide posts 22 and lower guide posts 43 cooperating with the guide post holes 32; the lower die 4 is also provided with a plurality of injection ports 44 connected with the lower end annular groove 41; the lower end of the lower die 4 is provided with a positioning boss 45 cooperating with the die-casting cylinder.

[0021] There are two guide post holes 32 on each of the four corners of the middle mold 3 for cooperating with the upper mold 2 and the lower mold 4. The four corners of the upper mold 2 are provided with four upper guide posts 22, and the four corners of the lower mold 4 are provided with four lower guide posts 43. After the upper mold 2, the middle mold 3 and the lower mold 4 are combined to form a cavity, the cavity includes a main cavity 31 for placing the rotor core 5 and an end ring cavity formed by the upper end ring groove 23 and the lower end ring groove 41 located at the end of the cavity of the upper mold 2 and the lower mold 4. The two walls of the upper end ring groove 23 and the lower end ring groove 41 have a draft angle of 1.5° for easy demolding, and the injection port 44 is in a trumpet shape, with the large hole facing outward and the small hole facing inward to facilitate the removal of waste from the die-casting hole.

[0022] The dummy shaft assembly 1 includes a shaft cylinder 12 positioned and matched with the upper mold 2 and the lower mold 4; the drive shaft 11 is slidably arranged in the middle of the shaft cylinder 12; the extrusion assembly 13 includes a first extrusion part 15 and a second extrusion part 16 which are arranged in different directions; the drive shaft 11 is transmission-connected with the first extrusion part 15 and the second extrusion part 16; the first extrusion part 15 includes a connecting rod structure, and the second extrusion part 16 includes a wedge block structure; a positioning block 14 is arranged on the shaft cylinder 12 to limit the moving direction of the drive shaft 11.

[0023] Specifically, the shaft cylinder 12 is a cylindrical structure, a through hole is provided in the middle of the shaft cylinder 12, the drive shaft 11 is slidably arranged in the through hole in the middle of the shaft cylinder 12, the upper end of the drive shaft 11 extends out of the shaft cylinder 12 and is connected to the external drive structure, and the lower end of the drive shaft 11 is transmission-connected with the first extrusion portion 15 and the second extrusion portion 16. Specifically, the first extrusion portion 15 is symmetrically arranged on both sides of the drive shaft 11 in the first direction, and the second extrusion portion 16 is symmetrically arranged on both sides of the drive shaft 11 in the second direction, wherein the first direction is perpendicular to the second direction, see the attached Fig.10 The first extrusion portion 15 and the second extrusion portion 16 convert the vertical movement of the drive shaft 11 into the lateral movement of the extrusion assembly 13, so that after the extrusion assembly 13 is extended into the shaft hole 512 of the rotor core 5, the first extrusion portion 15 and the second extrusion portion 16 are actuated by the drive shaft 11 to generate lateral movement, thereby providing a lateral extrusion force G on the end face of the shaft hole 512.

[0024] The first extrusion part 15 includes a connecting rod structure, and the second extrusion part 16 includes a wedge structure. The connecting rod structure of the first extrusion part 15 can provide a larger lateral displacement, which is convenient for positioning and aligning the shaft hole 512 of the punching sheet 51. The wedge structure of the second extrusion part 16 can provide a larger extrusion force, thereby better closing the gap 50 between the punching sheets 51.

[0025] The upper end of the shaft cylinder 12 is provided with an upper positioning portion 121 that cooperates with the false shaft hole 21 of the upper mold 2; the lower end of the shaft cylinder 12 is provided with a lower positioning portion 122 that cooperates with the positioning groove 42 of the lower mold 4; a limiting groove 113 is provided on the driving shaft 11, and a positioning block 14 relatively arranged on the shaft cylinder 12 is engaged with the limiting groove 113; one end of the driving shaft 11 extending out of the shaft cylinder 12 is connected to an external actuating mechanism, and the other end of the driving shaft 11 is provided with a first hinge shaft 111 and a first wedge block 112; the first hinge shaft 111 is connected to the connecting rod structure of the first extrusion part 15; the first wedge block 112 is connected to the wedge block structure of the second extrusion part 16.

[0026] Specifically, there are two groups of first hinge shafts 111 arranged side by side, each group has two first hinge shafts 111, and the first hinge shafts 111 of each group are connected to the connecting rod structure of the first extrusion part 15 in opposite directions, see the attached Fig.10 The connecting rod structure of each first extrusion part 15 is connected to two first hinge shafts 111 arranged side by side. The two sets of connecting rod structures make the first extrusion part 15 more stable when being pushed out; there are two first wedge blocks 112 and they are symmetrically arranged on both sides of the driving shaft 11.

[0027] The connecting rod structure of the first extrusion part 15 includes a driving rod 151 and a supporting rod 152; one end of the driving rod 151 is hinged to the first hinge shaft 111 of the driving shaft 11, and the other end is hinged to the middle part of the supporting rod 152; one end of the supporting rod 152 is hinged to the second hinge shaft 123 of the shaft tube 12, and the other end is transmission connected to the extrusion block 153.

[0028] Specifically, in the initial state, the angle between the driving rod 151 and the driving shaft 11 is close to vertical but not vertical. The translation of the driving rod 151 drives the driving shaft 11 to rotate from close to vertical to vertical. Within this angle range, the driving shaft 11 can apply as much thrust as possible to the support rod 152. Figure 7-11 One end of the support rod 152 is hinged to the second hinge shaft 123 of the shaft tube 12, and the other end is specifically connected to the extrusion block 153 through a sliding structure, so that the support rod 152 can push the extrusion block 153 to protrude linearly from the shaft tube 12 and squeeze the shaft hole 512 of the rotor core 5.

[0029] The extrusion block 153 has an arc-shaped end face adapted to the shaft hole 512 of the rotor core 5; the other side of the arc-shaped end face of the extrusion block 153 is provided with a convex ridge, and a plurality of waist-shaped holes 1531 are provided on the convex ridge; a sliding pin 1521 is provided at the end of the support rod 152, and the sliding pin 1521 is slidably matched with the waist-shaped hole 1531; a rotating shaft 1522 connected to the driving rod 151 is provided in the middle of the support rod 152.

[0030] Specifically, a slot is provided in the middle of the support rod 152, the rotating shaft 1522 is arranged in the slot, and the axial hole on the driving rod 151 is sleeved on the rotating shaft 1522 to push the support rod 152 to rotate through the driving rod 151; two convex ridges are provided on the back of the extrusion block 153, and two waist-shaped holes 1531 are provided on each convex ridge. Sliding pins 1521 are provided on both sides of one end of the support rod 152, and the sliding pins 1521 on both sides of the support rod 152 extend into two oppositely arranged waist-shaped holes 1531. The slot on the shaft cylinder 12 limits the extrusion block 153 to make a linear motion, and the extrusion block 153 is driven to move in a linear manner by the rotating support rod 152 in conjunction with the waist-shaped holes 1531 and the sliding pins 1521, wherein the angle setting of the driving rod 151 and the driving shaft 11 can greatly increase the thrust applied to the extrusion block 153.

[0031] There are two first wedge blocks 112 and they are symmetrically arranged on both sides of the drive shaft 11; the wedge block structure of the second extrusion part 16 includes a second wedge block 161 and a guide block 162; the second extrusion part 16 has an arc-shaped end face adapted to the shaft hole 512 of the rotor core 5, and the second wedge block 161 is arranged on the other side of the arc-shaped end face of the second extrusion part 16; the second wedge block 161 abuts against the first wedge block 112 of the drive shaft 11; guide parts are arranged on both sides of the guide block 162, and the guide parts are slidably arranged in the guide groove 124 of the shaft cylinder 12.

[0032] The motor rotor of the present invention is made of the above-mentioned cast aluminum rotor die-casting mold, and the rotor core 5 is pressed by multiple punching sheets 51; a shaft hole 512 is provided in the middle of the punching sheet 51, and multiple guide bar grooves 511 are opened in the circumferential direction of the punching sheet 51; the outer cylindrical end surface of the punching sheet 51 of the rotor core 5 is gap-matched and positioned with the main cavity 31 of the middle mold 3; after the mold is closed, the extrusion assembly 13 of the dummy shaft assembly 1 abuts against the shaft hole 512 of the punching sheet 51 of the rotor core 5 to form an inner cylindrical end surface.

[0033] A second protrusion 502 is arranged around the lower opening of the shaft hole 512 of the punch 51; a first protrusion 501 is arranged around the lower opening of the guide bar groove 511; the inclined end surface formed by the first protrusion 501 and the hole wall of the guide bar groove 511, and the inclined end surface formed by the second protrusion 502 and the hole wall of the shaft hole 512, both have an angle with the vertical direction.

[0034] Specifically, the guide groove 511 and the shaft hole 512 on the punching sheet 51 of the present invention are punched by a punching machine. During the punching process, the lower edges of the guide groove 511 and the shaft hole 512 are cut by the punching knife to form redundant materials, that is, the first protrusion 501 and the second protrusion 502 are formed; and the inclined end surface formed by the hole wall of the guide groove 511 and the first protrusion 501 has an angle A with the vertical direction, see Fig.14The inclined end face formed by the hole wall of the shaft hole 512 and the second protrusion 502 also has an angle with the vertical direction. The above structure makes the gap 50 formed between the punching sheets 51 not only extend laterally, but also because of the existence of the first protrusion 501 and the second protrusion 502, the gap 50 has a vertically extending part. Therefore, after the second protrusion 502 is laterally extruded by the extrusion assembly 13, it can play a role in closing the gap 50, thereby reducing and preventing the aluminum liquid from being squeezed into the gap 50.

[0035] After the mold is closed, the upper die pressing platform 211 of the upper mold 2 presses the upper part of the rotor core 5; the lower die pressing platform 421 of the lower mold 4 abuts against the lower part of the rotor core 5; the extrusion assembly 13 of the dummy shaft assembly 1 transversely squeezes the second protrusion 502 of the shaft hole 512 of the rotor core 5, and cooperates with the aluminum liquid delivered by the die-casting machine to transversely squeeze the first protrusion 501 of the guide groove 511 of the rotor core 5, so that the gap 50 between the punching sheets 51 of the rotor core 5 tends to close.

[0036] The extrusion assembly 13 of the dummy shaft assembly 1 applies a lateral thrust G to the inner wall of the shaft hole 512 of the rotor core 5, see the attached Fig.15 , so that the inner wall of the shaft hole 512 of the rotor core 5 has a higher straightness after die-casting, which improves the shaft hole quality of the cast aluminum rotor and facilitates the subsequent assembly with the motor shaft. At the same time, since the guide bar groove 511 and the shaft hole 512 have the first protrusion 501 and the second protrusion 502 extending vertically, the aluminum liquid output by the die-casting machine applies a lateral thrust F to the inner wall of the guide bar groove 511, and cooperates with the thrust G to extrude the second protrusion 502 laterally. At the same time, the upper mold generates downward pressure and the lower mold generates upward pressure, which squeezes the volume occupied by the punching sheet 51 laterally, so that the gap 50 between the punching sheets 51 tends to close at the first protrusion 501 and the second protrusion 502, which can reduce and prevent the aluminum liquid from being squeezed into the gap between the punching sheets 51, thereby reducing the lateral current of the motor and reducing the additional loss of the motor.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-cavity cast aluminum rotor die-casting mold, comprising an upper mold (2), a middle mold (3), and a lower mold (4), characterized in that: The middle mold (3) is provided with a plurality of main cavities (31); The upper die (2) is provided with an upper end annular groove (23) corresponding to the main cavity (31), and a false shaft hole (21) is provided at the center of the upper end annular groove (23); The lower die (4) is provided with a lower end annular groove (41) corresponding to the main cavity (31), and a positioning groove (42) is provided at the center of the lower end annular groove (41); The rotor core (5) is placed in the main cavity (31), and the main cavity (31) is a cylindrical hole and has a clearance fit with the rotor core (5); The dummy shaft assembly (1) is placed in the dummy shaft hole (21), the dummy shaft assembly (1) passes through the rotating shaft hole (512) in the middle of the rotor core (5), and the lower end of the dummy shaft assembly (1) is matched with the positioning groove (42); The extrusion assembly (13) on the dummy shaft assembly (1) acts on the side of the shaft hole (512) to achieve positioning of the punching sheets (51) of the rotor core (5), while closing the gaps (50) formed between the punching sheets (51).

2. The die-casting mold for an aluminum rotor according to claim 1, characterized in that: The middle mold (3) is provided with a plurality of guide post holes (32); The upper die (2) and the lower die (4) are respectively provided with an upper guide post (22) and a lower guide post (43) that cooperate with the guide post hole (32); The lower mold (4) is also provided with a plurality of injection ports (44) connected to the lower end annular groove (41); The lower end of the lower die (4) is provided with a positioning boss (45) that cooperates with the die-casting cylinder.

3. The die-casting mold for an aluminum rotor according to claim 2, characterized in that: The dummy shaft assembly (1) comprises a shaft cylinder (12) which is positioned and matched with the upper die (2) and the lower die (4); The drive shaft (11) is slidably disposed in the middle of the shaft cylinder (12); The extrusion assembly (13) comprises a first extrusion portion (15) and a second extrusion portion (16) which are arranged in different directions; The driving shaft (11) is drivingly connected to the first extrusion portion (15) and the second extrusion portion (16); The first extrusion portion (15) comprises a connecting rod structure, and the second extrusion portion (16) comprises a wedge block structure; The shaft cylinder (12) is provided with a positioning block (14) for limiting the moving direction of the drive shaft (11).

4. The die-casting mold for an aluminum rotor according to claim 3, characterized in that: The upper end of the shaft cylinder (12) is provided with an upper positioning portion (121) that cooperates with the false shaft hole (21) of the upper mold (2); The lower end of the shaft cylinder (12) is provided with a lower positioning portion (122) that cooperates with the positioning groove (42) of the lower mold (4); A limiting groove (113) is provided on the driving shaft (11), and a positioning block (14) arranged opposite to the shaft cylinder (12) is engaged with the limiting groove (113); One end of the drive shaft (11) extending out of the shaft tube (12) is connected to an external actuating mechanism, and the other end of the drive shaft (11) is provided with a first hinge shaft (111) and a first wedge block (112); The first hinge shaft (111) is connected to the connecting rod structure of the first extrusion portion (15); The first wedge block (112) is connected to the wedge block structure of the second extrusion portion (16).

5. The die-casting mold for an aluminum rotor according to claim 4, characterized in that: The connecting rod structure of the first extrusion part (15) comprises a driving rod (151) and a supporting rod (152); One end of the driving rod (151) is hinged to the first hinge shaft (111) of the driving shaft (11), and the other end is hinged to the middle part of the supporting rod (152); One end of the support rod (152) is hinged to the second hinge shaft (123) of the shaft cylinder (12), and the other end is transmission-connected to the extrusion block (153).

6. The die-casting mold for an aluminum rotor according to claim 5, characterized in that: The extrusion block (153) has an arc-shaped end surface adapted to the rotating shaft hole (512) of the rotor core (5); The other side of the arc-shaped end surface of the extrusion block (153) is provided with a convex ridge, and a plurality of waist-shaped holes (1531) are provided on the convex ridge; A sliding pin (1521) is provided at the end of the support rod (152), and the sliding pin (1521) is slidably matched with the waist-shaped hole (1531); A rotating shaft (1522) connected to the driving rod (151) is provided in the middle of the supporting rod (152).

7. The die-casting mold for an aluminum rotor according to claim 6, characterized in that: There are two first wedges (112) which are symmetrically arranged on both sides of the drive shaft (11); The wedge block structure of the second extrusion portion (16) comprises a second wedge block (161) and a guide block (162); The second extrusion portion (16) has an arc-shaped end surface adapted to the shaft hole (512) of the rotor core (5), and the second wedge block (161) is arranged on the other side of the arc-shaped end surface of the second extrusion portion (16); The second wedge block (161) abuts against the first wedge block (112) of the drive shaft (11); Guide parts are arranged on both sides of the guide block (162), and the guide parts are slidably arranged in the guide grooves (124) of the shaft cylinder (12).

8. A motor rotor, made by the cast aluminum rotor die-casting mold according to any one of claims 1 to 7, characterized in that: The rotor core (5) is formed by pressing a plurality of punching sheets (51); A rotating shaft hole (512) is provided in the middle of the punching sheet (51), and a plurality of guide grooves (511) are provided in the circumferential direction of the punching sheet (51); The outer cylindrical end surface of the punching sheet (51) of the rotor core (5) is clearance-matched with the main cavity (31) of the middle mold (3) and positioned; After the mold is closed, the extrusion component (13) of the dummy shaft component (1) abuts against the rotating shaft hole (512) of the punching sheet (51) of the rotor core (5) to form an inner circular end surface.

9. The motor rotor according to claim 8, characterized in that: Second protrusions (502) are arranged around the lower opening of the rotating shaft hole (512) of the punching sheet (51); A first protrusion (501) is arranged around the lower opening of the guide groove (511); The inclined end surface formed by the first protrusion (501) and the hole wall of the guide groove (511), and the inclined end surface formed by the second protrusion (502) and the hole wall of the shaft hole (512), both have an angle with the vertical direction.

10. The motor rotor according to claim 9, characterized in that: After the mold is closed, the upper mold pressing platform (211) of the upper mold (2) presses the upper part of the rotor core (5); The lower die pressing platform (421) of the lower die (4) abuts against the lower part of the rotor core (5); The extrusion assembly (13) of the dummy shaft assembly (1) laterally extrudes the second protrusion (502) of the shaft hole (512) of the rotor core (5), and cooperates with the aluminum liquid delivered by the die-casting machine to laterally extrude the first protrusion (501) of the guide bar groove (511) of the rotor core (5), so that the gap (50) between the punching sheets (51) of the rotor core (5) has a tendency to close.

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