Motor rotor, motor, power assembly, electric vehicle and compression injection molding device

Abstract

The invention provides a motor rotor, a motor, a power assembly, an electric vehicle and a compression injection molding device, the motor rotor comprises at least one rotor iron core and a plurality of magnetic steels, each rotor iron core comprises a plurality of magnetic steel grooves, and each magnetic steel groove penetrates through the rotor iron core along the axial direction of the motor rotor. Wherein each magnetic steel groove is used for accommodating one magnetic steel and one injection molding body, and one injection molding body is filled between the groove wall of one magnetic steel groove and one magnetic steel and is used for fixing one magnetic steel in one magnetic steel groove. Along the axial direction of the motor rotor, the length of the injection molding body is smaller than the length of the magnetic steel groove, and the length of the injection molding body is smaller than the length of the magnetic steel, so that at least part of the magnetic steel is exposed out of the injection molding body, the utilization rate of injection molding materials is improved, the production cost is reduced, and the appearance of the rotor core is attractive.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a motor rotor, a motor, a power assembly, an electric vehicle and a compression injection molding device. Background Art

[0002] The motor rotor includes a rotor core and multiple magnets. The multiple magnets need to be fixed in the multiple magnet slots of the rotor core. Currently, the flow injection molding method is used to melt the injection plastic and inject it into the mold. The plastic flows into the magnet slot through the injection channel in the mold. After the injection molding is completed, there will be residual material in the injection channel, which makes the utilization rate of the injection plastic low. In addition, before the injection molding, the magnet is not fixed in the magnet slot and is prone to deflection, which affects the dynamic balance of the rotor. In order to avoid the deflection of the magnet and the possible contact and conduction with the magnet slot wall, the magnet needs to be coated with an insulating coating, which is costly. Summary of the invention

[0003] The present application provides a motor rotor, a motor, a power assembly, an electric vehicle and a compression injection molding device.

[0004] In a first aspect, the present application provides a motor rotor, the motor rotor comprising at least one rotor core and a plurality of magnets, each rotor core comprising a plurality of magnet slots, each magnet slot passing through the rotor core along the axial direction of the motor rotor. Each magnet slot is used to accommodate a magnet and an injection molded body, an injection molded body is used to fill between a slot wall of a magnet slot and a magnet and to fix a magnet in a magnet slot. Along the axial direction of the motor rotor, the length of an injection molded body is less than the length of a magnet slot, and the length of an injection molded body is less than the length of a magnet.

[0005] In the embodiment of the present application, each magnetic steel slot is used to accommodate a magnetic steel and an injection molding body. The injection molding body is used to fill between the slot wall of the magnetic steel slot and the magnetic steel and to fix the magnetic steel in the magnetic steel slot. The injection molding body fixes the magnetic steel in the magnetic steel slot, which can prevent the magnetic steel from falling off during production, transportation or operation of the motor rotor. By controlling the weight of the injection molding body, the injection molding quality can be indirectly controlled, the waste of injection molding material can be avoided, and the injection molding appearance can be made more uniform.

[0006] In the embodiment of the present application, along the axial direction of the motor rotor, the length of the injection molded body is less than the length of the magnetic steel, so that during the process of compression injection molding of the injection plastic to form the injection molded body, the magnetic steel is at least partially exposed to the injection molded body, and no injection molding tailings are generated. The utilization rate of the injection plastic can reach 100%, which can reduce production costs and help make the appearance of the injection molding more beautiful. Along the axial direction of the motor rotor, the length of the injection molded body is less than the length of the magnetic steel slot, so that the injection molded body will not overflow the magnetic steel slot, so that the injection molded body will not pollute the motor rotor and the compression injection molding device, and it is also conducive to making the appearance of the injection molding more beautiful.

[0007] In one embodiment, along the axial direction of the motor rotor, the length of an injection-molded body is greater than half the length of a magnetic steel, and the difference between the length of an injection-molded body and a magnetic steel slot is less than half the length of a magnetic steel.

[0008] In the embodiment of the present application, along the axial direction of the motor rotor, the length of the injection molding body is greater than half the length of the magnetic steel, so that when the injection molding body is filled between the slot wall of the magnetic steel slot and the magnetic steel, the magnetic steel is fixed in the magnetic steel slot more stably. The difference between the length of the injection molding body and the magnetic steel slot is less than half the length of the magnetic steel, so that when the injection molding body is filled in the magnetic steel slot, the injection molding body will not overflow the magnetic steel slot, so that during the process of compression injection molding of the injection molding body, no injection molding tail material will be generated, and the utilization rate of the injection molding can reach 100%, which can reduce production costs and also help to make the appearance of the injection molding more beautiful.

[0009] In one embodiment, a magnetic steel includes two end faces, the two end faces are opposite to each other along the axial direction of the motor rotor, and the distance between one end face and an injection molded body is greater than the distance between the other end face and the injection molded body.

[0010] In the embodiment of the present application, the magnetic steel includes two end faces, the two end faces are opposite to each other along the axial direction of the motor rotor, the distance between one end face and the injection molded body is greater than the distance between the other end face and the injection molded body, and the distance between one end face and the injection molded body is larger, so that at least part of one end face is exposed to the injection molded body, so that the utilization rate of the injection molded material can reach 100%. At least part of one end face is exposed to the injection molded body, which also shows that compression injection molding can avoid the overflow of the injection molded material, will not pollute the product and tooling, and can make the appearance of the injection molded motor rotor more beautiful. The distance between the other end face and the injection molded body is smaller, so that the other end face of the magnetic steel will not accumulate too much injection molded body, thereby reducing the waste of injection molded material.

[0011] In one embodiment, a magnetic steel slot includes two notches, the two notches are opposite to each other along the axial direction of the motor rotor, one notch is on the same side as one end face, the other notch is on the same side as the other end face, and the distance between one notch and one injection molded body is greater than the distance between the other notch and one injection molded body.

[0012] In the embodiment of the present application, along the axial direction of the motor rotor, two notches are opposite to each other, and one notch is arranged on the same side as an end face, so that during the compression injection molding process, the magnet can be pushed into the magnet slot through one notch.

[0013] In the embodiment of the present application, the distance between one notch and the injection-molded body is greater than the distance between the other notch and the injection-molded body. The distance between one notch and the injection-molded body is larger, so that the injection-molded body will not overflow the magnetic steel slot, and when the injection-molded body is filled in the gap between the magnetic steel slot and the magnetic steel contained therein, the injection-molded body will not completely cover the magnetic steel, so that one end face of the magnetic steel may not be covered by the injection-molded body, making the appearance of the injection-molded motor rotor more beautiful. The distance between the other notch and the injection-molded body is smaller, so that there can be more injection-molded bodies between the other end face of the magnetic steel and the other notch, thereby reducing the waste of injection plastic and improving the fixing effect of the injection-molded body on the magnetic steel.

[0014] In one embodiment, along the axial direction of the motor rotor, the density of an injection molded body gradually decreases from the direction close to the other end surface to the direction close to the one end surface.

[0015] In the embodiment of the present application, since the injection molding body is squeezed into the gap between the magnetic steel and the magnetic steel slot by the magnetic steel from the end close to the support plate to the end away from the support plate, the end of the magnetic steel slot away from the support plate is in a free and open state, so that the density of the end of the injection molding body away from the support plate is less than the density of the end close to the support plate. The density of the injection molding body gradually decreases from the direction close to the other end surface to the direction close to the other end surface. The density of the injection molding body close to the other end surface is relatively large, which is conducive to fixing the magnetic steel more firmly. The density of the injection molding body close to one end surface is relatively small, so that the injection molding body will not continue to overflow the magnetic steel slot during the compression process.

[0016] In one embodiment, a surface of an injection-molded body facing away from an end face is flat.

[0017] In the embodiment of the present application, compression injection molding is adopted for the rotor core. Since there is no need to reserve exhaust holes during the injection molding process, there is no need to lift the other end face of the magnetic steel with a protrusion, and no groove is formed on the other end face of the magnetic steel. The surface of the injection molding body away from one end face is a plane, which is conducive to making the structure of the magnetic steel more regular and flat, and improving the utilization rate of the injection molding material.

[0018] In one embodiment, a magnetic steel includes two surfaces, and a slot wall of a magnetic steel slot includes two side walls, one surface is opposite to one side wall, and the other surface is opposite to the other side wall. The thickness of a portion of an injection molded body filled between one surface and one side wall is the same as the thickness of another portion filled between the other surface and the other side wall.

[0019] In the embodiment of the present application, the thickness of a part of the injection molded body filled between one surface and a side wall is the same as the thickness of another part filled between another surface and another side wall, so that the magnetic steel is fixed in the middle position of the magnetic steel slot, which is beneficial to the uniform position of the magnetic steel and prevents deflection, thereby improving the dynamic balance of the motor rotor.

[0020] In an embodiment of the present application, the thickness of a portion of the injection molded body filled between a surface and a side wall is the same as the thickness of another portion filled between another surface and another side wall. This can also prevent the magnetic steel from being conductive to the magnetic steel groove, thereby reducing the use of the magnetic steel insulating coating and reducing production costs.

[0021] In one embodiment, a thickness of a portion of an injection-molded body filling between a surface and a side wall is smaller than a difference between a length of the injection-molded body and a magnetic steel groove.

[0022] In the embodiment of the present application, the thickness of a portion of the injection molded body filled between a surface and a side wall is less than the difference in length between the injection molded body and the magnetic steel slot. The thickness of a portion of the injection molded body filled between a surface and a side wall is small, so that the magnetic steel can be fixed in the magnetic steel slot using a lesser mass of the injection molded body, thereby reducing the use of injection molded material and reducing production costs. The difference in length between the injection molded body and the magnetic steel slot is large, so that at least a portion of an end face of the injection molded body can be exposed to the injection molded body, so that the utilization rate of the injection molded material in the compression injection molding process reaches 100%, and the injection molded material can be prevented from overflowing, and the motor rotor and the compression injection molding device will not be contaminated, and the appearance of the injection molded motor rotor can be made more beautiful.

[0023] In the embodiment of the present application, the thickness of a portion of the injection-molded body filled between a surface and a side wall is less than the difference in length between the injection-molded body and the magnetic steel slot, which can facilitate compression injection molding of the rotor core. In the process of pushing the magnetic steel into the magnetic steel slot to squeeze the injection-molded body, even if part of the injection-molded body overflows to a height higher than one end face of the magnetic steel, it will tend to extend along the slot wall of the magnetic steel slot instead of covering one end face of the magnetic steel, thereby making the appearance of the injection-molded motor rotor more beautiful.

[0024] In one embodiment, the ratio of the volume of an injection molded body to the difference in volume between a magnetic steel slot and a magnetic steel is greater than or equal to 90%, and the ratio of the volume of an injection molded body to the difference in volume between a magnetic steel slot and a magnetic steel is less than or equal to 98%.

[0025] In the embodiment of the present application, the ratio of the volume of the injection-molded body to the difference between the volume of the magnetic steel slot and the magnetic steel is greater than or equal to 90%, so that there can be enough injection-molded bodies to firmly fix the magnetic steel in the magnetic steel slot, and the ratio of the volume of the injection-molded body to the difference between the volume of the magnetic steel slot and the magnetic steel is less than or equal to 98%, so that one end face of the magnetic steel can be at least partially uncovered by the injection-molded body, thereby not generating excess injection molding tailings, making the utilization rate of the injection molding material 100%, which can reduce production costs, and the injection molding material will not pollute the motor rotor and the compression injection molding device, which is conducive to making the injection molding appearance more beautiful.

[0026] In one embodiment, the motor rotor includes a plurality of rotor cores, which are stacked and arranged along the axial direction of the motor rotor, and there is no injection molding body between two adjacent rotor cores.

[0027] In the embodiment of the present application, the multiple rotor cores of the motor rotor are separately processed and injection molded and then stacked, so that there is no injection molded body between two adjacent rotor cores, so that the injection molded body will not overflow from between the multiple rotor cores, which is beneficial to the beauty of injection molding, and is also beneficial to reducing the waste of injection plastic and reducing production costs. The use of compression injection molding of a single rotor core can also facilitate the inspection of injection molding quality, and can reduce the use of high-voltage equipment in flow injection molding to avoid the overflow of injection plastic between multiple rotor cores, thereby reducing the investment and maintenance costs of injection molding equipment.

[0028] In a second aspect, the present application provides a motor, comprising a motor housing, a motor stator, a motor shaft and a motor rotor as in the first aspect, wherein the motor housing is used to be sleeved on and fixed to the motor stator, the motor stator is used to be sleeved on the motor rotor, and the motor rotor is used to be fixed to the motor shaft.

[0029] In the motor rotor of the embodiment of the present application, the injection molding body is filled in the gap between the magnetic steel slot and the magnetic steel, so that the magnetic steel is firmly fixed in the magnetic steel slot and the utilization rate of the injection molding body is improved, which is conducive to reducing production costs and making the rotor core look beautiful, thereby improving the overall appearance of the motor. The magnetic steel is fixed in the magnetic steel slot, which can facilitate the assembly of the motor and is also conducive to the balance and stability of the motor operation.

[0030] In a third aspect, the present application provides a powertrain, which includes a reducer and a motor as in the second aspect, wherein the motor shaft of the motor is used for transmission connection with the input shaft of the reducer, and the output shaft of the reducer is used for transmission connection with the wheels of the electric vehicle.

[0031] The motor in the embodiment of the present application includes a motor rotor. The motor rotor is formed by filling the injection molding body in the gap between the magnetic steel slot and the magnetic steel, so that the magnetic steel is firmly fixed in the magnetic steel slot and the utilization rate of the injection molding body is improved, which is beneficial to reducing production costs and making the rotor core look beautiful, thereby improving the overall aesthetics of the motor in the powertrain and further improving the product quality of the powertrain.

[0032] In a fourth aspect, the present application provides an electric vehicle, comprising a frame, a power battery and a powertrain as in the third aspect, wherein the frame is used to fix the powertrain, and the powertrain is used to drive wheels.

[0033] The powertrain in the embodiment of the present application includes a motor, and the rotor of the motor is formed by filling the injection molding body in the gap between the magnetic steel slot and the magnetic steel, so that the magnetic steel is firmly fixed in the magnetic steel slot and the utilization rate of the injection molding body is improved, which is beneficial to reducing production costs and making the rotor core look beautiful, thereby improving the overall aesthetics of the motor in the powertrain, improving the product quality of the powertrain, and further improving the overall performance of the vehicle.

[0034] In a fifth aspect, the present application provides a compression injection molding device, which is used to process and form a motor rotor as in the first aspect, and the compression injection molding device includes a positioning tool plate and a support plate, and along the axial direction of the motor rotor, a positioning tool plate and a support plate are used to be stacked on both sides of a rotor core respectively. Among them, a positioning tool plate includes a plurality of openings, an opening is used to align with a magnetic steel slot of a rotor core along the axial direction of the motor rotor, an opening is used to accommodate a push rod and a magnetic steel, a support plate is used to support an injection molding body precursor in a magnetic steel slot, and a push rod is used to drive a magnetic steel to squeeze an injection molding body precursor into a gap between a magnetic steel slot and a magnetic steel to form an injection molding body.

[0035] In an embodiment of the present application, along the axial direction of the motor rotor, the positioning tooling plate and the support plate are used to be stacked on both sides of a rotor core respectively, so that the rotor core and the magnetic steel in the magnetic steel slot can be supported by the support plate, and a rotor core can be compression injection molded from the positioning tooling plate.

[0036] In an embodiment of the present application, the positioning tooling plate includes a plurality of openings, one of the openings being aligned with a magnetic steel slot of the rotor core along the axial direction of the motor rotor, so that the magnet can be pushed into the magnetic steel slot from the opening of the positioning tooling plate, and by using the opening of the positioning tooling plate and the magnetic steel slot of the rotor core for positioning, the position of the inserted magnet can be made uniform without deflection, thereby improving the dynamic balance of the motor rotor.

[0037] In the embodiment of the present application, the opening is used to accommodate a push rod and a magnet, and the opening serves to guide and position the push rod and the magnet. It can be understood that the opening is used to accommodate the push rod and a part of the magnet. As the magnet is pushed into the magnet slot, the positions of the push rod and the magnet relative to the opening change until the magnet is completely pushed into the magnet slot.

[0038] In an embodiment of the present application, the magnetic steel slot is used to accommodate an injection molding body precursor, and the support plate is used to support the injection molding body precursor. The injection molding body precursor is placed in the magnetic steel slot before the magnetic steel is placed in the magnetic steel slot, so that in the process of pushing the magnetic steel into the magnetic steel slot, the placed injection molding body precursor can be squeezed, so that the injection molding body precursor forms an injection molding body between the magnetic steel slot and the magnetic steel. Fixing the magnetic steel in the magnetic steel slot through the injection molding body can also prevent the magnetic steel from falling off during the production of the motor rotor, and facilitate the handling of the rotor core during the production process. Placing the injection molding body precursor into the magnetic steel slot first and then compressing and injecting it can also indirectly control the injection molding quality by controlling the weight of the injection molding body precursor, avoiding waste of injection molding materials, and making the injection molding appearance more uniform.

[0039] In one embodiment, a magnetic steel slot includes two first side walls and two second side walls, the two first side walls are arranged opposite to each other, and the two second side walls are arranged opposite to each other. In the arrangement direction of the two first side walls, the width of an opening is less than the spacing between the two first side walls, and the width of an opening is greater than or equal to the width of a magnetic steel. In the arrangement direction of the two second side walls, the width of an opening is less than the spacing between the two second side walls, and the width of an opening is greater than or equal to the width of a magnetic steel.

[0040] In the embodiment of the present application, along the arrangement direction of the two first side walls, the width of an opening is smaller than the spacing between the two first side walls, so that when the magnetic steel is placed into the magnetic steel slot from the opening, along the arrangement direction of the two first side walls, the magnetic steel will not contact the two first side walls, which can avoid the magnetic steel from being connected to the two first side walls, thereby eliminating the need for the magnetic steel to have an insulating coating, which can reduce production costs. The width of the opening is greater than or equal to the width of the magnetic steel, so that along the arrangement direction of the two first side walls, the magnetic steel has enough space to pass through the opening smoothly and be pushed into the magnetic steel slot to be fixed by the injection molding body.

[0041] In the embodiment of the present application, along the arrangement direction of the two second side walls, the width of the opening is smaller than the spacing between the two second side walls, so that when the magnetic steel is placed into the magnetic steel slot from the opening, along the arrangement direction of the two second side walls, the magnetic steel will not contact the two second side walls, which can avoid the magnetic steel from being connected to the two second side walls, thereby eliminating the need for the magnetic steel to have an insulating coating, reducing the use of insulating coating, and reducing production costs. The width of the opening is greater than or equal to the width of the magnetic steel, so that along the arrangement direction of the two second side walls, the magnetic steel has enough space to pass through the opening smoothly and be pushed into the magnetic steel slot to be fixed by the injection molding body.

[0042] In the embodiment of the present application, the width of the opening is smaller than the spacing between the two first side walls, and the width of the opening is smaller than the spacing between the two second side walls, so that the four sides of the magnet will not contact the side walls of the magnet slot, so that the magnet can be precisely positioned and pushed into the magnet slot, so that the position of the magnet is uniform and will not be skewed, which is beneficial to improving the dynamic balance of the motor rotor and can also eliminate the insulating coating of the magnet, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0044] Figure 1 is a schematic diagram of the structure of an electric vehicle provided in an embodiment of the present application;

[0045] Figure 2 A schematic diagram of the structure of a powertrain provided in an embodiment of the present application;

[0046] Figure 3 is a schematic diagram of the structure of the motor provided in the embodiment of the present application;

[0047] Figure 4 is a flow chart of a compression injection molding method for a motor rotor provided in an embodiment of the present application;

[0048] Figure 5 is a schematic structural diagram of a compression injection molding device and a rotor core provided in an embodiment of the present application;

[0049] Figure 6 is another structural schematic diagram of a compression injection molding device and a rotor core provided in an embodiment of the present application;

[0050] Figure 7 is a schematic structural diagram of a rotor core provided in an embodiment of the present application;

[0051] Figure 8 It is a structural schematic diagram of a positioning tooling plate provided in an embodiment of the present application;

[0052] Fig. 9 is another structural schematic diagram of a compression injection molding device and a rotor core provided in an embodiment of the present application;

[0053] Fig.10 is another structural schematic diagram of a compression injection molding device and a rotor core provided in an embodiment of the present application;

[0054] Fig.11 is a schematic diagram of the structure of the motor rotor provided in an embodiment of the present application;

[0055] Fig.12 It is a schematic diagram of the process of flow injection molding provided in an embodiment of the present application;

[0056] Fig.13 It is another structural schematic diagram of the motor rotor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0058] In order to improve the utilization rate of injection molding materials and reduce production costs, the present application provides a motor rotor, which includes at least one rotor core and a plurality of magnets, each rotor core including a plurality of magnet slots, and each magnet slot runs through the rotor core along the axial direction of the motor rotor. Each magnet slot is used to accommodate a magnet and an injection molding body, and the injection molding body is used to fill between the slot wall of the magnet slot and the magnet and to fix the magnet in the magnet slot. Along the axial direction of the motor rotor, the length of the injection molding body is less than the length of the magnet slot, and the length of the injection molding body is less than the length of the magnet. By filling the injection molding body in the gap between the magnet slot and the magnet, the magnet is firmly fixed, the length of the injection molding body is less than the length of the magnet, so that the magnet is at least partially exposed to the injection molding body, the utilization rate of the injection molding material is improved, which is beneficial to reducing production costs and also beneficial to making the rotor core beautiful in appearance.

[0059] Figure 1 It is a schematic diagram of the structure of the electric vehicle 1 provided in an embodiment of the present application. Figure 2 is a schematic diagram of the structure of a powertrain 10 provided in an embodiment of the present application, Figure 3 It is a schematic diagram of the structure of the motor 11 provided in an embodiment of the present application.

[0060] In one embodiment, the electric vehicle 1 includes a powertrain 10, a frame 20, a power battery 30, and wheels 40. Figure 1 As shown, the power assembly 10 and the power battery 30 are fixed to the vehicle frame 20. The power assembly 10 is used to receive power from the power battery 30 and to drive the wheels 40.

[0061] In the embodiment of the present application, the power battery 30 may also be referred to as a battery pack. In the embodiment of the present application, the frame 20 may also be referred to as a vehicle body. In the embodiment of the present application, the electric vehicle 1 refers to a wheeled device driven or towed by a power device.

[0062] In one embodiment, the powertrain 10 includes a motor 11 and a reducer 12. Figure 2 and Figure 3As shown, the motor 11 includes a motor rotor 11a, a motor shaft 11b and a motor stator (not shown), and the reducer 12 includes a gear assembly (not shown), an input shaft (not shown) and an output shaft (not shown), wherein the input shaft receives the power transmitted by the motor shaft 11b of the motor 11 and transmits the power to the output shaft through the gear assembly. The gear assembly can be set as required, and can be a single-speed reduction gear assembly, a two-speed or multi-speed reduction gear assembly. The motor rotor 11a is fixedly sleeved on the motor shaft 11b, and the motor stator drives the motor rotor 11a to rotate after receiving alternating current, thereby driving the motor shaft 11b to rotate. The motor shaft 11b of the motor 11 is used for transmission connection with the input shaft of the reducer 12.

[0063] In one embodiment, the powertrain 10 further includes a motor controller 13, such as Figure 1 and Figure 2 As shown, the motor controller 13 is used to receive the direct current transmitted by the power battery 30, and convert the direct current into alternating current and transmit it to the motor 11. The motor 11 is used to convert the electrical energy into mechanical energy after receiving the alternating current, and transmit the mechanical energy to the reducer 12. The reducer 12 is connected to the wheel 40 in a driving manner, and the reducer 12 is used to transmit power to the wheel 40 to drive the wheel 40 to rotate.

[0064] At present, the most common way to fix the rotor core and the magnetic steel in the motor rotor of the permanent magnet synchronous motor is the flow injection molding method. The flow injection molding method refers to placing the rotor core and the magnetic steel in the mold, injecting the injection plastic into the mold after melting, and flowing into the magnetic steel slot through the injection channel in the mold, so that the magnetic steel is fixed in the magnetic steel slot. This flow injection molding method will leave injection tails in the injection molding channel after the injection molding is completed, which makes the utilization rate of the injection plastic low. The injection plastic will also remain on the end face of the rotor core, which not only affects the appearance but also makes the utilization rate of the injection plastic low. In addition, this flow injection molding method requires the magnetic steel to be inserted into the magnetic steel slot before injection molding. Before injection molding, because the magnetic steel is not fixed, the position of the magnetic steel in each magnetic steel slot is not uniform, which is not conducive to the dynamic balance of the electronic rotor after the injection molding is completed. In addition, before injection molding, because the magnetic steel is not fixed, the magnetic steel and the inner wall of the magnetic steel slot may contact and conduct. In order to avoid the contact between the magnetic steel and the inner wall of the magnetic steel slot, it is necessary to add an insulating coating on the surface of the magnetic steel, which increases the process and cost. When multiple rotor cores of a motor rotor are injection molded at the same time, the stacking of multiple rotor cores makes the axial length longer. The flow injection molding method makes it difficult to confirm the filling conditions of the middle and lower magnetic steel slots when the injection plastic is injected from the top of the multiple rotor cores to the lower magnetic steel slots, making it impossible to confirm the injection molding quality such as the filling rate of the injection plastic in the entire motor rotor. It also requires that vent holes be reserved during the injection molding process so that the injection plastic can flow smoothly from the upper magnetic steel slots of the multiple rotor cores to the lower magnetic steel slots. Furthermore, the magnetic steel is not fixed before injection molding, and it is necessary to add a magnetic steel removal tooling during the production and transportation of the motor rotor to prevent the magnetic steel from falling off from the magnetic steel slot during transportation, which increases production costs. Injection molding equipment and molds using flow injection molding are expensive and have high maintenance costs.

[0065] The present application uses compression injection molding to perform injection molding on the magnetic steel and the rotor core. The injection molding will not produce tailings and the utilization rate of the injection molding material is high. By accurately positioning the positioning tooling plate and the rotor core, the uniform position of the magnetic steel is ensured, the dynamic balance of the rotor can be improved, and the magnetic steel plating can be eliminated to achieve the effect of reducing costs. By controlling the weight of the injection molding material, the injection molding quality can be indirectly controlled. After the magnetic steel is pressed in, it is fixed by the injection molding material, which can prevent the magnetic steel from falling off during rotor production and facilitate the handling of the core during the production process. It can also reduce the investment and maintenance costs of injection molding equipment.

[0066] The following is a detailed description of the method for compression injection molding of the motor rotor 11a provided in an embodiment of the present application.

[0067] Figure 4 is a flow chart of a compression injection molding method of a motor rotor 11a provided in an embodiment of the present application, Figure 5 is a structural schematic diagram of a compression injection molding device 400 and a rotor core 100 provided in an embodiment of the present application, Figure 6 is another structural schematic diagram of the compression injection molding device 400 and the rotor core 100 provided in an embodiment of the present application, Figure 7 is a schematic structural diagram of a rotor core 100 provided in an embodiment of the present application, Figure 8 It is a structural schematic diagram of the positioning tooling plate 410 provided in an embodiment of the present application.

[0068] In one embodiment, a method for compression injection molding of a motor rotor 11a includes steps S100 and S200. Figure 4 The detailed steps are as follows.

[0069] Step S100, providing a rotor core 100, a plurality of magnetic steels 200, a plurality of injection molding precursors 300 and a compression injection molding device 400. The compression injection molding device 400 includes a positioning tooling plate 410 and a support plate 420, such as Figures 5 to 7 As shown, along the motor rotor axial direction O, the positioning tooling plate 410 and the support plate 420 are used to be stacked on both sides of the rotor core 100, respectively, as shown in FIG. Figure 8 As shown, the positioning tooling plate 410 includes a plurality of openings 411, one opening 411 is used to align with a magnetic steel slot 110 of the rotor core 100 along the axial direction O of the motor rotor, one opening 411 is used to accommodate a push rod 431 and a magnetic steel 200, one magnetic steel slot 110 is used to accommodate an injection molding precursor 300, and the support plate 420 is used to support the injection molding precursor 300.

[0070] Step S200, as Figure 5 and Figure 6 As shown, a magnetic steel 200 is driven to squeeze a molded body precursor 300 into a gap between a magnetic steel slot 110 in a rotor core 100 and a magnetic steel 200 to form a molded body 300a.

[0071] In one embodiment, the material of the injection molding body precursor 300 includes at least one of polyamide (PA), polyethylene (PE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), thermoplastic polyurethane (TPU), and thermoplastic elastomer (TPE).

[0072] In one embodiment, the volume of an injection molding body precursor 300 is smaller than the volume difference between a magnetic steel slot 110 and a magnetic steel 200, so that when an injection molding body precursor 300 is squeezed in the gap between the magnetic steel slot 110 and the magnetic steel 200, it will not overflow the magnetic steel slot 110, thereby improving the utilization rate of the injection molding material. By controlling the weight of the injection molding body precursor 300, the injection molding quality can be indirectly controlled, the waste of injection molding material can be avoided, and the injection molding appearance can be made more uniform.

[0073] In one embodiment, the volume of an injection molding body precursor 300 is recorded as V1, the volume difference between a magnetic steel slot 110 and a magnetic steel 200 is recorded as V2, the ratio of V1 to V2 is greater than or equal to 90%, and the ratio of V1 to V2 is less than or equal to 98%. Under the condition that the injection molding material can fix the magnetic steel 200 and the magnetic steel slot 110, the material cost can also be reduced. In the embodiment of the present application, the rotor core 100 and the injection molding body precursor 300 placed in the magnetic steel slot 110 are supported by the support plate 420, and the magnetic steel 200 is pushed into the magnetic steel slot 110 from the opening 411 of the positioning tooling plate 410 by the push rod 431, and the injection molding body precursor 300 is squeezed to form an injection molding body 300a between the magnetic steel 200 and the magnetic steel slot 110, and then the magnetic steel 200 is fixed in the magnetic steel slot 110. By extruding the injection molding body precursor 300 in a compression injection molding manner, controlling the amount of the injection molding body precursor 300 placed in the magnetic steel groove 110 can make the utilization rate of the injection molding material reach 100%, reduce the generation of injection molding tailings, avoid waste, and reduce production costs.

[0074] In the implementation of the present application, the positioning tooling plate 410 and the support plate 420 of the compression injection molding device 400 have lower costs than the mold of the flow injection molding method, which effectively reduces the cost of the device.

[0075] In one embodiment, the method for compression injection molding of the motor rotor 11a further includes providing a heating device (not shown) to heat the rotor core 100 and the injection molding body precursor 300. The heating device surrounds the rotor core 100. Exemplarily, the heating device heats the rotor core 100 by induction heating. In the embodiment of the present application, the heating device is used to heat the rotor core 100 and the injection molding body precursor 300 to soften the injection molding body precursor 300, and to ensure that the injection molding body precursor 300 will not cool and harden when placed in the magnetic steel slot 110 of the rotor core 100, so that the magnetic steel 200 squeezes the injection molding body precursor 300 to form the injection molding body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110. The magnetic steel 200 is pushed until it cannot be pushed, so that the magnetic steel 200 can fully squeeze the injection molding body precursor 300 placed in the magnetic steel slot 110, and also so that the magnetic steel 200 can be fully fixed in the magnetic steel slot 110.

[0076] In one embodiment, the injection molding precursor 300 may be preheated before being placed into the magnetic steel groove 110 , so that the injection molding precursor 300 can be softened faster in the magnetic steel groove 110 .

[0077] In one embodiment, if Figure 5 and Figure 6 As shown, the width of the push rod 431 is smaller than the width of each magnetic steel 200 , so that the push rod 431 can pass through the opening 411 of the positioning tooling plate 410 , and better push the magnetic steel 200 completely into the magnetic steel slot 110 .

[0078] In one embodiment, if Figure 7 As shown, the magnetic steel slot 110 of the rotor core 100 also includes two magnetic isolation grooves 118. When the injection molding body precursor 300 is placed in the magnetic steel slot 110, a sealing member is placed in each magnetic isolation groove 118 to prevent the two magnetic isolation grooves 118 from being filled with injection molding material. After the magnetic steel 200 is fixed to the magnetic steel slot 110 by compression injection molding, the sealing member is pulled out from the two magnetic isolation grooves 118.

[0079] The compression injection molding device 400 will be described in detail below.

[0080] In one embodiment, if Figure 5 and Figure 6 As shown, the compression injection molding device 400 includes a positioning tooling plate 410 and a support plate 420. Along the motor rotor axial direction O, the positioning tooling plate 410 and the support plate 420 are used to be stacked on both sides of a rotor core 100. Figure 8 As shown, the positioning tooling plate 410 includes a plurality of openings 411, one opening 411 is aligned with a magnetic steel slot 110 of the rotor core 100 along the motor rotor axial direction O, the opening 411 is used to accommodate a push rod 431 and a magnetic steel 200, the magnetic steel slot 110 is used to accommodate an injection molding body precursor 300, the support plate 420 is used to support the injection molding body precursor 300, and the push rod 431 is used to drive the magnetic steel 200 to extrude the injection molding body precursor 300 into the gap between the magnetic steel slot 110 and the magnetic steel 200 to form an injection molding body 300a.

[0081] In an embodiment of the present application, along the axial direction O of the motor rotor, the positioning tooling plate 410 and the support plate 420 are used to be stacked on both sides of a rotor core 100 respectively, so that the rotor core 100 and the magnetic steel 200 in the magnetic steel slot 110 can be supported by the support plate 420, and a rotor core 100 can be compression injection molded from the positioning tooling plate 410.

[0082] In the embodiment of the present application, the positioning tooling plate 410 includes a plurality of openings 411, and an opening 411 is aligned with a magnetic steel slot 110 of the rotor core 100 along the axial direction O of the motor rotor, so that the magnet 200 can be pushed into the magnetic steel slot 110 from the opening 411 of the positioning tooling plate 410, and by using the opening 411 of the positioning tooling plate 410 and the magnetic steel slot 110 of the rotor core 100 for positioning, the position of the inserted magnet 200 can also be made uniform without deflection, thereby improving the dynamic balance of the motor rotor 11a.

[0083] In the embodiment of the present application, the opening 411 is used to accommodate a push rod 431 and a magnet 200. The opening 411 serves to guide and position the push rod 431 and the magnet 200. It can be understood that the opening 411 is used to accommodate the push rod 431 and a portion of the magnet 200. As the magnet 200 is pushed into the magnet slot 110, the positions of the push rod 431 and the magnet 200 and the opening 411 change until the magnet 200 is completely pushed into the magnet slot 110.

[0084] In the embodiment of the present application, the magnetic steel slot 110 is used to accommodate an injection molding precursor 300, and the support plate 420 is used to support the injection molding precursor 300. Before the magnetic steel 200 is placed in the magnetic steel slot 110, the injection molding precursor 300 is placed in the magnetic steel slot 110, so that in the process of pushing the magnetic steel 200 into the magnetic steel slot 110, the placed injection molding precursor 300 can be squeezed, so that the injection molding precursor 300 forms an injection molding body 300a between the magnetic steel slot 110 and the magnetic steel 200. Fixing the magnetic steel 200 in the magnetic steel slot 110 through the injection molding body 300a can also prevent the magnetic steel 200 from falling off during the production of the motor rotor 11a, and facilitate the handling of the rotor core 100 during the production process. Placing the injection molding body precursor 300 into the magnetic steel slot 110 and then performing compression injection molding can also indirectly control the injection molding quality by controlling the weight of the injection molding body precursor 300, thereby avoiding waste of injection molding material and making the injection molding appearance more uniform.

[0085] In one embodiment, the opening 411 includes a guide section 411a and a receiving section 411b. Figure 5 and Figure 6 As shown, the guide section 411a is an inverted tapered hole, and along the motor rotor axial direction O, the guide section 411a is located above the accommodating section 411b.

[0086] In the embodiment of the present application, the guide section 411a is an inverted tapered hole, which facilitates the positioning of the magnetic steel 200 into the receiving section 411b of the opening 411, and reduces the difficulty of the magnetic steel 200 in its magnetic steel slot 110. Along the motor rotor axial direction O, the guide section 411a is located above the receiving section 411b, so that the magnetic steel 200 can be positioned and placed into the magnetic steel slot 110 after the guide section 411a is placed, which is conducive to the precise positioning of the magnetic steel 200 and can also reduce the difficulty of the process.

[0087] Fig. 9 is another structural schematic diagram of the compression injection molding device 400 and the rotor core 100 provided in an embodiment of the present application, Fig.10 It is another structural schematic diagram of the compression injection molding device 400 and the rotor core 100 provided in an embodiment of the present application.

[0088] In one embodiment, the magnetic steel slot 110 includes two first side walls 111 and 112 and two second side walls 113 and 114. Fig. 9 and Fig.10 As shown, the two first side walls 111 and 112 are arranged opposite to each other, and the two second side walls 113 and 114 are arranged opposite to each other. In particular, along the arrangement direction X of the two first side walls 111 and 112, the width of an opening 411 is less than the spacing between the two first side walls 111 and 112, and the width of the opening 411 is greater than or equal to the width of the magnetic steel 200. Along the arrangement direction Y of the two second side walls 113 and 114, the width of the opening 411 is less than the spacing between the two second side walls 113 and 114, and the width of the opening 411 is greater than or equal to the width of the magnetic steel 200.

[0089] In the embodiments of the present application, Fig. 9 As shown, along the arrangement direction X of the two first side walls 111 and 112, the width of an opening 411 is recorded as L1, the spacing between the two first side walls 111 and 112 is recorded as L2, and the width of the magnetic steel 200 is recorded as L3. L1<L2, so that when the magnetic steel 200 is placed into the magnetic steel groove 110 from the opening 411, along the arrangement direction X of the two first side walls 111 and 112, the magnetic steel 200 will not contact the two first side walls 111 and 112, which can avoid the magnetic steel 200 and the two first side walls 111 and 112 from being connected, so that the magnetic steel 200 does not need to have an insulating coating, which can reduce the production cost. L1≥L3, so that along the arrangement direction X of the two first side walls 111 and 112, the magnetic steel 200 has enough space to smoothly pass through the opening 411 and be pushed into the magnetic steel groove 110 to be fixed by the injection molding body 300a.

[0090] In the embodiments of the present application, Fig.10 As shown, along the arrangement direction Y of the two second side walls 113 and 114, the width of the opening 411 is recorded as L4, the spacing between the two second side walls 113 and 114 is recorded as L5, and the width of the magnetic steel 200 is recorded as L6. L4<L5, so that when the magnetic steel 200 is placed into the magnetic steel groove 110 from the opening 411, along the arrangement direction Y of the two second side walls 113 and 114, the magnetic steel 200 will not contact the two second side walls 113 and 114, which can avoid the magnetic steel 200 and the two second side walls 113 and 114 from being connected, so that the magnetic steel 200 does not need to have an insulating coating, the use of insulating coating is reduced, and the production cost can be reduced. L4≥L6, so that along the arrangement direction Y of the two second side walls 113 and 114, the magnetic steel 200 has enough space to smoothly pass through the opening 411 and be pushed into the magnetic steel groove 110 to be fixed by the injection molding body 300a.

[0091] In the embodiments of the present application, Fig. 9 and Fig.10As shown, L1<L2, L4<L5, so that the four sides of the magnet 200 will not contact the side walls of the magnet slot 110, so that the magnet 200 can be pushed into the magnet slot 110 with precise positioning, so that the position of the magnet 200 is uniform and will not be skewed, which is beneficial to improving the dynamic balance of the motor rotor 11a, and can also eliminate the insulating coating of the magnet 200, thereby reducing production costs.

[0092] In one embodiment, the opening 411 includes two first hole walls 411c, 411d and two second hole walls 411e, 411f. Fig. 9 and Fig.10 As shown, the two first hole walls 411c and 411d are opposite to each other along the arrangement direction X of the two first side walls 111 and 112, and the two second hole walls 411e and 411f are opposite to each other along the arrangement direction Y of the two second side walls 113 and 114. The spacing between one first hole wall 411c and one adjacent first side wall 111 is equal to the spacing between another first hole wall 411d and another adjacent first side wall 112. The spacing between one second hole wall 411e and one adjacent second side wall 113 is equal to the spacing between another second hole wall 411f and another adjacent second side wall 114.

[0093] In the embodiments of the present application, Fig. 9 As shown, the spacing between a first hole wall 411c and a first side wall 111 adjacent thereto is equal to the spacing between another first hole wall 411d and another first side wall 112 adjacent thereto, so that after the magnetic steel 200 is pushed into the magnetic steel groove 110, the magnetic steel 200 can be located in the middle position of the magnetic steel groove 110 along the arrangement direction X of the two first side walls 111 and 112, which can not only avoid the magnetic steel 200 and the magnetic steel groove 110 from being conducted, but also can make the magnetic steel 200 precisely positioned along the arrangement direction X of the two first side walls 111 and 112 when being pushed into the magnetic steel groove 110, so that the arrangement is more regular, so that the injection material between the magnetic steel 200 and the magnetic steel groove 110 is more evenly distributed, and the fixation between the magnetic steel 200 and the magnetic steel groove 110 is more stable.

[0094] In the embodiments of the present application, Fig.10As shown, the spacing between a second hole wall 411e and a second side wall 113 adjacent thereto is equal to the spacing between another second hole wall 411f and another second side wall 114 adjacent thereto, so that after the magnetic steel 200 is pushed into the magnetic steel groove 110, the magnetic steel 200 can be located in the middle position of the magnetic steel groove 110 along the arrangement direction Y of the two second side walls 113, 114, which can not only avoid the magnetic steel 200 and the magnetic steel groove 110 from being conducted, but also can make the magnetic steel 200 precisely positioned along the arrangement direction Y of the two second side walls 113, 114 when pushed into the magnetic steel groove 110, so that the arrangement is more regular, so that the injection material between the magnetic steel 200 and the magnetic steel groove 110 is more evenly distributed, and the fixation between the magnetic steel 200 and the magnetic steel groove 110 is more stable.

[0095] In the embodiment of the present application, the spacing between a first hole wall 411c and a first side wall 111 adjacent thereto is equal to the spacing between another first hole wall 411d and another first side wall 112 adjacent thereto, and the spacing between a second hole wall 411e and a second side wall 113 adjacent thereto is equal to the spacing between another second hole wall 411f and another second side wall 114 adjacent thereto, so that the magnetic steel 200 can be precisely positioned and fixed in the middle of the magnetic steel slot 110, ensuring that the magnetic steel 200 does not contact the two first side walls 111, 112 and the two second side walls 113, 114 of the magnetic steel slot 110, thereby eliminating the insulating coating on the surface of the magnetic steel 200, reducing the production cost, and making the magnetic steel 200 arranged neatly.

[0096] When processing multiple rotor cores 100 by flow injection molding, it is necessary to stack multiple rotor cores 100 first, and use high-voltage equipment to apply a force along the axial direction O to the multiple rotor cores 100, and then inject flowing injection molding material from the top of the multiple rotor cores 100. The injection molding material flows from the injection channel of the injection mold along the axial direction O from top to bottom into the magnetic steel slots 110 of the multiple rotor cores 100, making it difficult to confirm the filling conditions in the magnetic steel slots of the middle and lower rotor cores 100. In order to prevent the injection molding material from overflowing from the gaps between the rotor cores 100, the high-voltage equipment compresses the multiple rotor cores 100, which makes the investment and maintenance costs of the injection molding equipment high. The injection molding channel will cause injection molding tailings to be generated during the flow injection molding process, and the utilization rate of the injection molding material is low. In addition, injection molding tailings will remain on the surface of the rotor core 100, making the injection molding appearance of the rotor core 100 uneven. Furthermore, when the multiple rotor cores 100 are injection molded by flow injection molding, bubbles will be generated in the magnetic steel slots in the multiple rotor cores 100 to form cavities, and additional exhaust holes need to be provided, which increases the difficulty and cost of the process.

[0097] In one embodiment, the motor rotor 11a includes a plurality of rotor cores 100. The compression injection molding method of the present application can be used for each rotor core 100 to extrude the magnetic steel 200 into the magnetic steel slot 110, and then the plurality of rotor cores 100 that have been subjected to compression injection molding can be stacked.

[0098] In the embodiment of the present application, compression injection molding is used for each rotor core 100 to squeeze the injection molded body 300a between the magnetic steel 200 and the magnetic steel slot 110. The axial dimension of a single rotor core 100 is relatively small, which can make the extrusion fluidity of the injection molded body precursor 300 better, and the compression injection molding process is smooth, so that the compression injection molding device 400 does not need to be equipped with exhaust holes, and it is not easy to form a cavity between the magnetic steel 200 and the magnetic steel slot 110. Since the end of the magnetic steel slot 110 away from the support plate 420 is in a free and open state, even if bubbles are generated in the injection molding material during the compression injection molding process, the bubbles will be discharged from the end of the magnetic steel slot 110 away from the support plate 420, and there is no need to design an additional exhaust hole. There is no need for an injection molding channel, and injection molding will not produce injection molding tailings, and the utilization rate of the injection molding material is high.

[0099] In the embodiment of the present application, compression injection molding is performed on each rotor core 100 separately. By controlling the weight of the injection molding body precursor 300, the injection molding material can be prevented from overflowing the magnetic steel slot 110, and the injection molding appearance of the rotor core 100 can be made more uniform, which is conducive to the beauty of the injection molding appearance. It is also convenient to check the injection molding quality of the rotor core 100 to ensure product quality. It can also reduce the use of high-voltage equipment and reduce the investment and maintenance costs of injection molding equipment.

[0100] The structure of the motor rotor 11a manufactured by using the above-mentioned compression injection molding device 400 will be described in detail below.

[0101] Fig.11 It is a schematic diagram of the structure of the motor rotor 11a provided in an embodiment of the present application.

[0102] In one embodiment, a motor rotor 11a includes at least one rotor core 100 and a plurality of magnetic steels 200. Figure 7 and Fig.11 As shown, each rotor core 100 includes a plurality of magnetic steel slots 110, and each magnetic steel slot 110 runs through the rotor core 100 along the axial direction O of the motor rotor. Each magnetic steel slot 110 is used to accommodate a magnetic steel 200 and an injection molded body 300a, and the injection molded body 300a is used to fill between the slot wall of the magnetic steel slot 110 and the magnetic steel 200 and to fix the magnetic steel 200 in the magnetic steel slot 110. Along the axial direction O of the motor rotor, the length of the injection molded body 300a is less than the length of the magnetic steel slot 110, and the length of the injection molded body 300a is less than the length of the magnetic steel 200.

[0103] In the embodiment of the present application, each magnetic steel slot 110 is used to accommodate a magnetic steel 200 and an injection molding body 300a. The injection molding body 300a is used to fill between the slot wall of the magnetic steel slot 110 and the magnetic steel 200 and to fix the magnetic steel 200 in the magnetic steel slot 110. The injection molding body 300a fixes the magnetic steel 200 in the magnetic steel slot 110, which can prevent the magnetic steel 200 from falling off during the production, transportation or operation of the motor rotor 11a. By controlling the weight of the injection molding body 300a, the injection molding quality can be indirectly controlled, the waste of injection molding material can be avoided, and the injection molding appearance can be made more uniform.

[0104] In the embodiments of the present application, Fig.11 As shown, along the motor rotor axial direction O, the length of the magnetic steel 200 is recorded as L7, the length of the injection molding body 300a is recorded as L8, and the length of the magnetic steel slot 110 is recorded as L9. L7>L8, so that during the process of compression injection molding of the injection molding body 300a, the magnetic steel 200 is at least partially exposed to the injection molding body 300a, and no injection molding tailings are generated. The utilization rate of the injection molding can reach 100%, which can reduce production costs and help make the appearance of the injection molding more beautiful. L8<L9, so that the injection molding body 300a will not overflow the magnetic steel slot 110, so that the injection molding body 300a will not pollute the motor rotor 11a and the compression injection molding device 400, and it is also helpful to make the appearance of the injection molding more beautiful.

[0105] The injection molded body 300 a and the injection molded body precursor 300 are made of the same material.

[0106] In one embodiment, if Fig.11 As shown, the injection molding body 300a is used to be squeezed into the gap between the magnetic steel groove 110 and the magnetic steel 200 contained therein and to fix the magnetic steel 200 in the magnetic steel groove 110. The injection molding body 300a is squeezed between the magnetic steel groove 110 and the magnetic steel 200 by the magnetic steel 200. Compared with the flow injection molding method, the injection molding body 300a can save injection molding material. The injection molding body 300a has an interaction force with the magnetic steel 200 and the groove wall of the magnetic steel groove 110, so that the magnetic steel 200 is more firmly fixed in the magnetic steel groove 110.

[0107] In one embodiment, if Fig.11 As shown, along the motor rotor axial direction O, the length of the injection molded body 300 a is greater than half of the length of the magnetic steel 200 , and the difference in length between the injection molded body 300 a and the magnetic steel slot 110 is less than half of the length of the magnetic steel 200 .

[0108] In the embodiment of the present application, the length of the injection molded body 300a is L8, the length of the magnetic steel 200 is L7, and the length of the magnetic steel groove 110 is L9, and L8>0.5L7, so that when the injection molded body 300a is filled between the groove wall of the magnetic steel groove 110 and the magnetic steel 200, the magnetic steel 200 is more stably fixed in the magnetic steel groove 110. The difference between L8 and L9 is less than 0.5L7, so that when the injection molded body 300a is filled in the magnetic steel groove 110, the injection molded body 300a will not overflow the magnetic steel groove 110, so that in the process of compression injection molding of the injection molded body 300a, no injection molding tail material is generated, and the injection molded material utilization rate can reach 100%, which can reduce the production cost and also help to make the appearance of the injection molding more beautiful.

[0109] In one embodiment, the magnetic steel 200 includes two end surfaces 210 and 220, which are opposite to each other along the motor rotor axis O, and the distance between one end surface 210 and the injection molded body 300a is greater than the distance between the other end surface 220 and the injection molded body 300a.

[0110] In the embodiments of the present application, Fig.11 As shown, the magnetic steel 200 includes two end faces 210 and 220, and the two end faces 210 and 220 are opposite to each other along the axial direction O of the motor rotor. The distance between one end face 210 and the injection molding body 300a is greater than the distance between the other end face 220 and the injection molding body 300a. The distance between the end face 210 and the injection molding body 300a is large, so that at least part of the end face 210 is exposed to the injection molding body 300a, so that during the compression injection molding process, not only the magnetic steel 200 is completely fixed in the magnetic steel slot 110, but also the utilization rate of the injection molding material can reach 100%. At least part of the end face 210 is exposed to the injection molding body 300a, which also shows that the compression injection molding can avoid the overflow of the injection molding material, will not pollute the product and tooling, and can make the appearance of the injection molding motor rotor 11a more beautiful. The distance between the end face 220 and the injection molding body 300a is small, so that the end face 220 of the magnetic steel 200 will not accumulate too much of the injection molding body 300a, thereby reducing the waste of the injection molding material.

[0111] In one embodiment, the distance between the end surface 220 and the injection molded body 300 a is zero, and the end surface 220 is flush with the bottom of the magnetic steel slot 110 .

[0112] In one embodiment, if Fig.11 As shown, the magnetic steel slot 110 includes two slots 115, and the two slots 115 are opposite to each other along the axial direction O of the motor rotor. One slot 115a is on the same side as one end surface 210, and the other slot 115b is on the same side as the other end surface 220. The distance between the slot 115a and the injection molded body 300a is greater than the distance between the slot 115b and the injection molded body 300a.

[0113] In the embodiment of the present application, along the motor rotor axial direction O, the two notches 115 are opposite to each other, and one notch 115a is arranged on the same side as the end surface 210, so that during the compression injection molding process, the magnetic steel 200 can be pushed into the magnetic steel slot 110 through the notch 115a.

[0114] In the embodiment of the present application, the distance between the notch 115a and the injection molded body 300a is greater than the distance between the notch 115b and the injection molded body 300a. The distance between the notch 115a and the injection molded body 300a is large, so that the injection molded body 300a will not overflow the magnetic steel groove 110, and when the injection molded body 300a is filled in the gap between the magnetic steel groove 110 and the magnetic steel 200 contained therein, the injection molded body 300a will not completely cover the magnetic steel 200, so that the end face 210 of the magnetic steel 200 may not be covered by the injection molded body 300a, making the appearance of the injection molded motor rotor 11a more beautiful. The distance between the notch 115b and the injection molded body 300a is small, so that there are more injection molded bodies 300a between the other end face 220 of the magnetic steel 200 and the notch 115b, thereby reducing the waste of injection molded plastic.

[0115] In one embodiment, the distance between the notch 115b and the injection molded body 300a is zero, so that the other end surface 220 of the magnetic steel 200 does not contact the injection molded body 300a, further reducing the waste of the injection molded material and improving the utilization rate of the injection molded material.

[0116] In one embodiment, if Fig.11 As shown, the distance between the injection molded body 300a and the notch 115a is greater than the distance between the magnetic steel 200 and the notch 115a.

[0117] In the embodiment of the present application, along the axial direction O of the motor rotor, the distance between the injection molded body 300a and the slot 115a is recorded as L10, and the distance between the magnetic steel 200 and the slot 115a is recorded as L11, L10>L11, so that at least part of the end surface 210 of the injection molded body 300a can be exposed from the injection molded body 300a, so that the utilization rate of the injection plastic in the compression injection molding process reaches 100%, L10>L11, and it also means that compression injection molding can avoid overflow of the injection plastic, will not contaminate the motor rotor 11a and the compression injection molding device 400, and can make the appearance of the injection molded motor rotor 11a more beautiful.

[0118] In one embodiment, if Fig.11 As shown, the difference between the distance between the magnetic steel 200 and the notch 115 a and the distance between the injection molded body 300 a and the notch 115 a is 1 mm, that is, the difference between L10 and L11 is 1 mm.

[0119] In one embodiment, if Fig.11 As shown, along the motor rotor axial direction O, the density of the injection molded body 300 a gradually decreases from the direction close to the other end surface 220 to the direction of the one end surface 210 .

[0120] In the embodiment of the present application, since the injection molded body 300a is squeezed by the magnetic steel 200 from the end close to the support plate 420 to the end away from the support plate 420 into the gap between the magnetic steel 200 and the magnetic steel slot 110, the end of the magnetic steel slot 110 away from the support plate 420 is in a free and open state, so that the density of the end of the injection molded body 300a away from the support plate 420 is less than the density of the end close to the support plate 420. The density of the injection molded body 300a gradually decreases from the direction close to the other end face 220 to the direction close to the one end face 210. The density of the injection molded body 300a close to the end face 220 is relatively large, which is conducive to making the magnetic steel 200 more firmly fixed. The density of the injection molded body 300a close to the end face 210 is relatively small, so that the injection molded body 300a will not continue to overflow the magnetic steel slot 110 during the compression process.

[0121] Fig.12 This is a schematic diagram of the flow injection molding process provided in the embodiment of the present application. It should be noted that: Fig.12 The arrow in the middle left picture indicates the flow direction of the injection molding material. Fig.12 The middle right figure shows the schematic structural diagram of the rotor core 100 after flow injection molding.

[0122] When the rotor core 100 is molded by flow injection molding, Fig.12 As shown, it is necessary to additionally form an exhaust channel 451 at the bottom of the magnetic steel 200. For example, a protrusion 452 is formed on the lower mold 450 to form an exhaust channel 451 between the magnetic steel 200 and the lower mold 450, so that the surface of the injection molded body 300a close to the lower mold 450 after the injection molding is completed has a groove, making the surface uneven, and the injection molding material remains in the exhaust channel 451, which reduces the utilization rate of the injection molding material and is not conducive to reducing the production cost.

[0123] In one embodiment, if Fig.11 As shown, the surface of the injection-molded body 300 a facing away from the end surface 210 is a plane.

[0124] In the embodiments of the present application, Fig.11 As shown, the rotor core 100 is subjected to compression injection molding. Since there is no need to reserve exhaust holes during the injection molding process, there is no need to lift the end face 220 of the magnetic steel 200 with a protrusion, and no groove is formed on the end face 220 of the magnetic steel 200. The surface of the injection molding body 300a away from the end face 210 is a plane, which is conducive to making the structure of the magnetic steel 200 more regular and flat, and improving the utilization rate of the injection molding material.

[0125] In one embodiment, part of the injection molded body 300a is squeezed between the support plate 420 and the magnetic steel 200. The surface of the part of the injection molded body 300a away from the end surface 210 is a plane. In one embodiment, all of the injection molded bodies 300a are squeezed in the gap between the magnetic steel 200 and the magnetic steel slot 110. At this time, the surface of the injection molded body 300a away from the end surface 210 refers to the surface of the part of the injection molded body 300a located in the gap between the magnetic steel 200 and the magnetic steel slot 110 away from the end surface 210.

[0126] In one embodiment, the magnetic steel 200 further includes two surfaces 230, 240, and the slot wall of the magnetic steel slot 110 includes two side walls 116, 117. Fig.11 As shown, one surface 230 is opposite to one side wall 116, and the other surface 240 is opposite to the other side wall 117. The thickness of a portion of the injection molded body 300a filled between the surface 230 and the side wall 116 is the same as the thickness of another portion filled between the surface 240 and the side wall 117.

[0127] In the embodiment of the present application, the thickness of a portion of the injection molded body 300a filling between the surface 230 and the side wall 116 is the same as the thickness of another portion filling between the surface 240 and the side wall 117, so that the magnet 200 is fixed in the middle position of the magnet slot 110, which is beneficial to the uniform position of the magnet 200 and prevents it from being skewed, thereby improving the dynamic balance of the motor rotor 11a.

[0128] In the embodiment of the present application, the thickness of a portion of the injection molded body 300a filling between the surface 230 and the side wall 116 is the same as the thickness of another portion filling between the surface 240 and the side wall 117. This can also prevent the magnetic steel 200 from being conductively connected to the magnetic steel slot 110, thereby reducing the use of the insulating coating of the magnetic steel 200 and reducing the production cost.

[0129] It should be noted that, without considering the processing tolerance, the thickness of a portion of the injection molded body 300 a filled between the surface 230 and the side wall 116 is the same as the thickness of another portion of the injection molded body 300 a filled between the surface 240 and the side wall 117 .

[0130] In one embodiment, if Fig.11 As shown, at least a portion of at least one surface 230 , 240 is exposed from the injection molded body 300 a .

[0131] In the embodiment of the present application, at least a portion of at least one surface 230, 240 is exposed to the injection molding body 300a, so that during the compression injection molding process, not only the magnetic steel 200 is completely fixed in the magnetic steel slot 110, but also the utilization rate of the injection molding material can reach 100%. At least a portion of at least one surface 230, 240 is exposed to the injection molding body 300a, which also shows that the compression injection molding can avoid the overflow of the injection molding material, and will not contaminate the motor rotor 11a and the compression injection molding device 400, which can make the appearance of the injection molding motor rotor 11a more beautiful.

[0132] In one embodiment, the thickness of a portion of the injection molded body 300a filling between the surface 230 and the side wall 116 is different from the thickness of another portion filling between the surface 240 and the side wall 117, so that the magnet 200 is not in contact with the magnet slot 110 and the magnet 200 and the side wall of the magnet slot 110 are parallel along the axial direction O of the motor rotor.

[0133] In one embodiment, if Fig.11 As shown, the injection molded body 300 a is squeezed between each surface 230 , 240 of the magnetic steel 200 and the side walls 116 , 117 of the magnetic steel slot 110 .

[0134] In the embodiment of the present application, each surface 230, 240 of the magnetic steel 200 is spaced apart from the side walls 116, 117 of the magnetic steel slot 110, so that the magnetic steel 200 will not contact the side walls 116, 117 of the magnetic steel slot 110, thereby avoiding conduction between the magnetic steel 200 and the magnetic steel slot 110, thereby eliminating the insulating coating of the magnetic steel 200 and reducing the production cost.

[0135] In one embodiment, if Fig.11 As shown, the thickness of a portion of the injection-molded body 300 a filling between the surface 230 and the side wall 116 is less than the difference between the length of the injection-molded body 300 a and the magnetic steel slot 110 .

[0136] In the embodiment of the present application, the thickness of the portion of the injection molding body 300a filled between the surface 230 and the side wall 116 is less than the difference between the length of the injection molding body 300a and the magnetic steel slot 110. The thickness of the portion of the injection molding body 300a filled between the surface 230 and the side wall 116 is small, so that the magnetic steel 200 can be fixed in the magnetic steel slot 110 using a less mass of the injection molding body 300a, thereby reducing the use of injection molding material and reducing production costs. The difference between the length of the injection molding body 300a and the magnetic steel slot 110 is large, so that at least part of the end face 210 of the injection molding body 300a can be exposed to the injection molding body 300a, so that the utilization rate of the injection molding material in the compression injection molding process reaches 100%, and the injection molding material can be prevented from overflowing, and the motor rotor 11a and the compression injection molding device 400 will not be contaminated, and the appearance of the injection molding motor rotor 11a can be made more beautiful.

[0137] In the embodiment of the present application, the thickness of a portion of the injection molded body 300a filled between the surface 230 and the side wall 116 is less than the difference between the length of the injection molded body 300a and the magnetic steel slot 110, which can facilitate the compression injection molding of the rotor core 100. In the process of pushing the magnetic steel 200 into the magnetic steel slot 110 to squeeze the injection molded body 300a, even if part of the injection molded body 300a overflows to a height higher than the end face 210 of the magnetic steel 200, it will tend to extend closer to the slot wall of the magnetic steel slot 110 instead of covering the end face 210 of the magnetic steel 200, thereby making the appearance of the injection molded motor rotor 11a more beautiful.

[0138] In one embodiment, if Fig.11 As shown, the ratio of the volume of the injection molded body 300a to the volume difference between the magnetic steel slot 110 and the magnetic steel 200 is greater than or equal to 90%, and the ratio of the volume of the injection molded body 300a to the volume difference between the magnetic steel slot 110 and the magnetic steel 200 is less than or equal to 98%.

[0139] In the embodiment of the present application, the ratio of the volume of the injection molded body 300a to the difference between the volumes of the magnetic steel slot 110 and the magnetic steel 200 is greater than or equal to 90%, so that there can be enough injection molded bodies 300a to firmly fix the magnetic steel 200 in the magnetic steel slot 110, and the ratio of the volume of the injection molded body 300a to the difference between the volumes of the magnetic steel slot 110 and the magnetic steel 200 is less than or equal to 98%, so that the end face 210 of the magnetic steel 200 can be at least partially not covered by the injection molded body 300a, so that no excess injection molding tailings are generated, so that the utilization rate of the injection molding material is 100%, which can reduce the production cost, and the injection molding material will not pollute the motor rotor 11a and the compression injection molding device 400, which is conducive to making the appearance of the injection molding more beautiful.

[0140] In one embodiment, if Fig.11 As shown, the filling rate of the injection molded body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is greater than or equal to 90%, and the filling rate of the injection molded body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is less than or equal to 98%.

[0141] In the embodiment of the present application, the filling rate of the injection molding body 300a in the gap between the magnet 200 and the magnet groove 110 is greater than or equal to 90%, so that the magnet 200 can be firmly fixed in the magnet groove 110 by the injection molding body 300a, and the filling rate of the injection molding body 300a in the gap between the magnet 200 and the magnet groove 110 is less than or equal to 98%, so that the end face 210 of the magnet 200 can be at least partially exposed to the injection molding body 300a, and no excess injection molding tail material is generated, so that the utilization rate of the injection molding material is 100%, which can reduce the production cost, and the injection molding material will not pollute the motor rotor 11a and the compression injection molding device 400, which is conducive to making the appearance of the injection molding more beautiful.

[0142] It should be noted that the filling rate refers to the percentage of the space in the magnetic steel slot 110 excluding the magnetic steel 200 occupied by the injection molded body 300 a.

[0143] In one embodiment, the filling rate of the injection molded body 300 a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is 95%.

[0144] In one embodiment, the filling rate of the injection molded body 300 a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is 97%.

[0145] In one embodiment, the filling rate of the injection molded body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is the same as the ratio of the difference between the volume of the injection molded body precursor 300 and the volume of the magnetic steel slot 110 and the magnetic steel 200. The filling rate of the injection molded body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is controlled according to the volume of the injection molded body precursor 300. The volume of the injection molded body 300a in the gap between the magnetic steel 200 and the magnetic steel slot 110 is the same as that of the injection molded body precursor 300.

[0146] Fig.13 It is another structural schematic diagram of the motor rotor 11a provided in an embodiment of the present application.

[0147] In one embodiment, the motor rotor 11a includes a plurality of rotor cores 100, such as Fig.13 As shown, a plurality of rotor cores 100 are stacked and arranged along the axial direction O of the motor rotor, and there is no injection molding body 300 a between two adjacent rotor cores 100 .

[0148] In the embodiment of the present application, the multiple rotor cores 100 of the motor rotor 11a are individually processed and injection molded and then stacked, so that there is no injection molded body 300a between two adjacent rotor cores 100, so that the injection molded body 300a will not overflow from between the multiple rotor cores 100, which is beneficial to the beauty of injection molding, and is also beneficial to reducing the waste of injection molding and reducing production costs. The use of compression injection molding of a single rotor core 100 can also facilitate the inspection of injection molding quality, and can reduce the use of high-voltage equipment in flow injection molding to avoid the overflow of injection molding between multiple rotor cores 100, thereby reducing the investment and maintenance costs of injection molding equipment.

[0149] The motor rotor, motor, powertrain, electric vehicle and compression injection molding device provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and embodiments of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific embodiments and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A motor rotor, characterized in that: The motor rotor comprises at least one rotor core and a plurality of magnetic steels, each of the rotor cores comprises a plurality of magnetic steel slots, and each of the magnetic steel slots penetrates the rotor core along the axial direction of the motor rotor, wherein: Each of the magnetic steel slots is used to accommodate one of the magnetic steels and an injection molded body, wherein the injection molded body is used to fill between the slot wall of one of the magnetic steel slots and the one magnetic steel and to fix the one magnetic steel in the one magnetic steel slot; Along the axial direction of the motor rotor, the length of the injection-molded body is smaller than the length of the magnetic steel slot, and the length of the injection-molded body is smaller than the length of the magnetic steel.

2. The motor rotor according to claim 1, characterized in that: Along the axial direction of the motor rotor, the length of the injection-molded body is greater than half of the length of the magnetic steel, and the difference between the length of the injection-molded body and the length of the magnetic steel slot is less than half of the length of the magnetic steel.

3. The motor rotor according to claim 1 or 2, characterized in that: The magnetic steel comprises two end faces, the two end faces are opposite to each other along the axial direction of the motor rotor, and the distance between one end face and the injection molded body is greater than the distance between the other end face and the injection molded body.

4. The motor rotor according to claim 3, characterized in that: The magnetic steel slot includes two notches, which are opposite to each other along the axial direction of the motor rotor, one notch is on the same side as the one end face, and the other notch is on the same side as the other end face, and the distance between the one notch and the one injection-molded body is greater than the distance between the other notch and the one injection-molded body.

5. The motor rotor according to claim 3, characterized in that: Along the axial direction of the motor rotor, the density of the one injection molded body gradually decreases from the direction close to the other end surface to the one end surface.

6. The motor rotor according to claim 3, characterized in that: The surface of the one injection-molded body facing away from the one end surface is a plane.

7. The motor rotor according to any one of claims 1 to 5, characterized in that: The one magnetic steel includes two surfaces, and the slot wall of the one magnetic steel slot includes two side walls, one of the surfaces is opposite to one of the side walls, and the other surface is opposite to the other side wall, wherein: The thickness of a portion of the one injection-molded body filled between the one surface and the one side wall is the same as the thickness of another portion of the one injection-molded body filled between the other surface and the other side wall.

8. The motor rotor according to claim 7, characterized in that: The thickness of a portion of the one injection-molded body filled between the one surface and the one side wall is smaller than the difference between the length of the one injection-molded body and the one magnetic steel groove.

9. The motor rotor according to any one of claims 1 to 8, characterized in that: The ratio of the volume of the injection molded body to the difference between the volumes of the magnetic steel slot and the magnetic steel is greater than or equal to 90%, and the ratio of the volume of the injection molded body to the difference between the volumes of the magnetic steel slot and the magnetic steel is less than or equal to 98%.

10. The motor rotor according to any one of claims 1 to 9, characterized in that: The motor rotor comprises a plurality of rotor cores, and the plurality of rotor cores are stacked and arranged along the axial direction of the motor rotor, and there is no injection molding body between two adjacent rotor cores.

11. A motor, characterized in that: The motor comprises a motor housing, a motor stator, a motor shaft and a motor rotor as described in any one of claims 1 to 10, wherein the motor housing is used to sleeve and fix the motor stator, the motor stator is used to sleeve the motor rotor, and the motor rotor is used to be fixed to the motor shaft.

12. A powertrain, characterized in that: The power assembly includes a reducer and the motor as claimed in claim 11, the motor shaft of the motor is used for driving connection with the input shaft of the reducer, and the output shaft of the reducer is used for driving connection with the wheels of the electric vehicle.

13. An electric vehicle, characterized in that: The electric vehicle comprises a frame, a power battery and a powertrain as claimed in claim 12, wherein the frame is used to fix the powertrain, and the motor of the powertrain is used to receive power from the power battery and to drive the wheels through the reducer.

14. A compression injection molding device, characterized in that: The compression injection molding device is used to process and form the motor rotor according to any one of claims 1 to 10, and the compression injection molding device comprises a positioning tooling plate and a support plate, and along the axial direction of the motor rotor, the positioning tooling plate and the support plate are used to be stacked on both sides of the rotor core respectively, wherein: The positioning tooling plate includes a plurality of openings, one of the openings is used to align with a magnetic steel slot of the rotor core along the axial direction of the motor rotor, the opening is used to accommodate a push rod and a magnetic steel, the support plate is used to support an injection molding body precursor in the magnetic steel slot, and the push rod is used to drive the magnetic steel to extrude the injection molding body precursor into the gap between the magnetic steel slot and the magnetic steel to form the injection molding body.

15. The compression injection molding device according to claim 14, characterized in that: The magnetic steel slot comprises two first side walls and two second side walls, the two first side walls are arranged opposite to each other, and the two second side walls are arranged opposite to each other, wherein: Along the arrangement direction of the two first side walls, the width of the one opening is smaller than the interval between the two first side walls, and the width of the one opening is greater than or equal to the width of the one magnetic steel; Along the arrangement direction of the two second side walls, the width of the one opening is smaller than the interval between the two second side walls, and the width of the one opening is greater than or equal to the width of the one magnetic steel.

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