New energy motor shaft and processing technology thereof

Abstract

The invention provides a new energy motor shaft and a machining process thereof.The new energy motor shaft comprises a shaft extension part, an internal spline and a non-shaft extension part, a front end hole is formed in one side of the shaft extension part, a matching hole is formed in the other side of the shaft extension part, and the front end hole communicates with the matching hole; the inner spline is arranged in the front end hole, and the axes of the inner spline, the front end hole and the matching hole are located on the same axis and used for transmitting torque outwards. The non-shaft extension part is arranged in the matching hole in an interference fit mode and used for sealing one side of the front end hole, the end, away from the shaft extension part, of the non-shaft extension part is fixed to the rotary transformer rotor, the structure of the new energy motor shaft is a blind hole shaft, the front end hole and the matching hole are communicated through a two-section type shaft, and after heat treatment is conducted on an internal spline in the shaft extension part, the front end hole and the matching hole are separated from each other. The internal spline can be secondarily machined in a secondary hard drawing finish machining mode, the precision of tooth shape parameters of the internal spline shaft is improved, and therefore transmission noise is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a new energy motor shaft and its processing technology. Background Art

[0002] The new energy motor shaft is a key component for connecting the motor and the wheel or the transmission system. It is usually made of materials such as high carbon steel, alloy steel or aluminum alloy, and has high strength and stiffness to withstand various stresses generated during the driving of electric vehicles.

[0003] The motor shaft with internal splines and its manufacturing method disclosed in the publication number CN108131380A includes a shaft body. A spline sleeve is sleeved at the left end of the shaft body. An annular gasket clamping groove is opened at the left end of the spline sleeve. Reinforcing ribs are integrally formed on the side wall of the shaft body. The right end of the shaft body is connected to the output end shaft, and key position pin holes are opened on the output end shaft.

[0004] For the existing internal splines in the blind hole of the motor shaft, the tooth profile parameter accuracy changes greatly after heat treatment, and the internal splines in the blind hole at the shaft end cannot be machined twice after heat treatment. Only by improving the accuracy of the pre-heat hobbing process and controlling the heat treatment deformation amount can the accuracy of the internal splines in the blind hole be improved, resulting in a complex processing technology and unable to guarantee the machining accuracy of the internal splines, thereby reducing the transmission efficiency and service life of the motor shaft. Summary of the Invention

[0005] In view of this, the present invention provides a new energy motor shaft and its processing technology. The new energy motor shaft adopts a two-stage shaft, and the front end hole is connected to the mating hole, so that after the internal splines in the shaft extension are heat-treated, the internal splines can be machined twice by the method of secondary hard drawing finishing, improving the accuracy of the tooth profile parameters of the internal spline shaft, thereby reducing the transmission noise and increasing the service life.

[0006] The technical solution of the present invention is realized as follows: In the first aspect, the present invention provides a new energy motor shaft, including a shaft extension, internal splines and a non-shaft extension. Among them, A front end hole is opened on one side of the shaft extension, and a mating hole is opened on the other side, and the front end hole is connected to the mating hole; The internal splines are arranged in the front end hole, and the axes of the internal splines, the front end hole and the mating hole are all on the same axis, and are used to transmit torque outward; The non-shaft extension is arranged in the mating hole by interference fit, used to seal one side of the front end hole, and one end of the non-shaft extension away from the shaft extension is fixed to the resolver rotor.

[0007] On the basis of the above technical solutions, preferably, the shaft extension includes a front shaft section, a middle platform section and a rear shaft section. Among them, The front shaft section and the rear shaft section are respectively fixed on both sides of the middle platform section, and the diameter of the middle platform section is larger than the diameters of the front shaft section and the rear shaft section; The mating hole is opened on one side of the rear shaft section away from the middle platform section, and a through hole is opened on the side of the rear shaft section close to the front shaft section. The front end hole is arranged on one side of the front shaft section, and the through hole is communicated with the front end hole and the mating hole; The front shaft section, the middle platform section and the rear shaft section are of an integrally formed structure.

[0008] On the basis of the above technical solutions, preferably, the through hole, the front end hole and the mating hole form an inner cavity, the inner cavity is filled with grease, and a grinding wheel run-out groove is opened on the inner wall of the mating hole to make the non-shaft extension part fit tightly with the mating hole and seal one side of the inner cavity.

[0009] On the basis of the above technical solutions, preferably, it further includes a matching part and a sealing part. Among them, the matching part is arranged in the front end hole, and the matching part meshes with the internal spline to transmit torque to the matching part; the sealing part is sleeved on the outside of the matching part and abuts against the inner wall of the front end hole to seal the other side of the inner cavity.

[0010] On the basis of the above technical solutions, preferably, it further includes at least two bearings. Among them, at least two bearings are respectively arranged on the outside of the non-shaft extension part and the front shaft section, and one side bearing abuts against the middle platform section, and the other side bearing abuts against the end face of the rear shaft section to support the entire motor shaft.

[0011] On the basis of the above technical solutions, preferably, it further includes two magnetic separation parts, a plurality of rotor cores and fasteners. Among them, Both of the two magnetic separation parts are sleeved on the outside of the rear shaft section and are arranged at intervals, and one side magnetic separation part abuts against the middle platform section; A plurality of rotor cores are all sleeved on the outside of the rear shaft section, and the plurality of rotor cores are arranged in sequence and abut between the two magnetic separation parts; The fastener is fixed on the outside of the rear shaft section and abuts against the other side magnetic separation part to press the position of the rotor core.

[0012] On the basis of the above technical solutions, preferably, a plurality of first convex parts extending towards the axis are arranged on the inner side of the rotor core; a plurality of first key grooves are opened on the outside of the rear shaft section, the number and positions of the key grooves are correspondingly arranged with the first convex parts, and the first convex parts abut in the key grooves, and the outer contour shape of the first convex parts matches the inner contour shape of the key grooves to transmit the torque generated by the motor.

[0013] On the basis of the above technical solution, preferably, a boss portion is provided on the non-axial extension portion, and the boss portion is arranged on a side away from the shaft extension portion, a threaded hole is provided on the end face of the non-axial extension portion away from the shaft extension portion, a second keyway is provided on the outer side of the boss portion, a second protrusion extending toward the axis is provided on the inner side of the rotary rotor, the rotary rotor is sleeved on the outer side of the boss portion, and the second protrusion abuts in the second keyway, a clamping screw is threadedly connected in the threaded hole, and the end of the clamping screw abuts against the rotary rotor to lock the rotary rotor and the non-axial extension portion.

[0014] On the basis of the above technical solution, preferably, a center hole is provided on the side of the non-axial extension portion away from the threaded hole, the front end hole, the matching hole and the opening of the threaded hole for positioning the ejector pin during machine tool processing.

[0015] In a second aspect, the present invention further provides a new energy motor shaft processing process, using the new energy motor shaft as described above, comprising the following steps: S1: Clamp the shaft extension part and the non-shaft extension part on the machine tool chuck respectively, drill center holes at both ends of the shaft extension part and the non-shaft extension part respectively to serve as machining positioning references, drill front end holes, matching holes and through holes on the shaft extension part, and drill threaded holes on the non-shaft extension part; S2: Use a pin to push up each center hole, and finish turning all cylindrical surfaces, so that the shaft extension part forms a front shaft section, a middle platform section and a rear shaft section, and a boss section is formed on the non-shaft extension part; S3: milling the shaft extension part and the non-shaft extension part using a milling machine to generate a first keyway and a second keyway respectively; S4: Clamp the shaft extension on the machine chuck, use a gear shaping machine to shape the internal spline, set the spindle stroke number to 150~200str / min, use at least 5 feeds in the radial direction, and gradually reduce the feed amount and feed speed for 6~10min; S5: Put the shaft extension part and the non-shaft extension part into the carburizing furnace for carburizing treatment, the heat treatment temperature is 860~900℃, and the surface hardness after carburizing reaches 56~62HRC; S6: Grind each center hole using a grinder; S7: Clamp the shaft extension on the hard gear drawing equipment, use carbide broaches to perform secondary finishing on the internal spline, and at the same time finish the internal spline tooth shape and internal spline minor diameter. The broaching speed is controlled at 40~100m / min, and the broaching stroke generally only takes 1~2 seconds. The roughness Ra is ≤1.6μm, and the single-side tooth thickness allowance for broaching is 0.018mm; the cross-bar distance variation is ≤0.03mm; the single-side broaching allowance for major and minor diameters is 0.06mm; S8: Clamp the shaft extension part, use the minor diameter of the internal spline for positioning, and grind the bearing installation position of the bearing and the outer wall of the shaft extension part; for the non-shaft extension part, use the center hole for positioning and grind the bearing installation position of the bearing. S9: Install a lifting ring screw at the tail end of the non-shaft extension part to cooperate with the threaded hole. Use a hook to put the non-shaft extension part into the liquid nitrogen tank. Set the cooling temperature to -150 ± 10°C and the cooling time to 10 - 20 seconds. After cooling is completed, use the hook to take out the non-shaft extension part from the liquid nitrogen tank and directly install it into the mating hole on the shaft extension part for interference fit. The interference amount is between 0.01 - 0.03 mm. Wait for the temperature to return to normal to complete the machining and assembly of the motor shaft.

[0016] A new energy motor shaft and its processing technology of the present invention have the following beneficial effects compared with the prior art: (1) By setting the shaft extension part and the non-shaft extension part, the new energy motor shaft is divided into a two-section shaft. The shaft extension part is provided with an internal spline for transmission, and the front end hole is connected to the mating hole. After heat treatment of the internal spline in the shaft extension part, the internal spline can be machined twice by the method of secondary hard drawing to improve the accuracy of the tooth profile parameters of the internal spline shaft, which is beneficial to reducing the angular error during the transmission of the internal and external splines, reducing the spline transmission clearance and the side clearance variation, thereby reducing the transmission noise and increasing the service life. (2) By setting the shaft extension part and the internal spline as an integral forming structure, the connection gaps and potential fault points between various parts are eliminated, making the shaft extension part more robust and durable as a whole, capable of withstanding greater forces and torques, and improving the stability and reliability of the motor. (3) By setting the non-shaft extension part and the shaft extension part to be assembled by the liquid cooling method, a more precise connection is ensured, and at the same time, there is no risk of material damage in the liquid cooling method assembly. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a three-dimensional structure diagram of the new energy motor shaft of the present invention; Figure 2 It is a sectional view of the structure of the shaft extension part of the present invention; Figure 3 It is a sectional view of the structure of the non-shaft extension part of the present invention; Figure 4 It is a sectional view of the connection structure between the shaft extension part and the non-shaft extension part of the present invention; Figure 5Front view of the connection structure between the new energy motor shaft and the rotor of the present invention; Figure 6 Cross-sectional view of the connection structure between the new energy motor shaft and the rotor of the present invention; Figure 7 Side view of the structure of the rotor core of the present invention; Figure 8 Side view of the structure of the resolver rotor of the present invention; Figure 9 Schematic diagram of the structure of the hard drawn gear cutter of the present invention. Specific embodiments

[0019] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] For the large change in the tooth profile parameter accuracy of the internal spline in the blind hole at the end of the new energy motor shaft after heat treatment, which cannot meet the accuracy requirements of the market, and the internal spline in the blind hole at the end of the shaft cannot be machined twice after heat treatment. Currently, only by improving the accuracy of the gear hobbing process before heat treatment and controlling the heat treatment deformation can the accuracy of the internal spline in the blind hole be improved. Therefore, a new energy motor shaft and its processing technology.

[0021] As Figures 1-9 shown, a new energy motor shaft of the present invention includes a shaft extension part 1, an internal spline 2, and a non-shaft extension part 3. Among them, a front end hole 100 is provided on one side of the shaft extension part 1, and a mating hole 110 is provided on the other side, and the front end hole 100 communicates with the mating hole 110; the internal spline 2 is arranged in the front end hole 100, and the axes of the internal spline 2, the front end hole 100, and the mating hole 110 are all on the same axis, and are used to transmit torque outward; the non-shaft extension part 3 is arranged in the mating hole 110 by interference fit, is used to seal one side of the front end hole 100, and one end of the non-shaft extension part 3 far from the shaft extension part 1 is fixed to the resolver rotor.

[0022] It should be noted that in this embodiment, the new energy motor shaft adopts a two-piece shaft, which is divided into a shaft extension part 1 and a non-shaft extension part 3; the shaft extension part 1 is provided with an internal spline 2 for transmission, and the front end hole 100 is communicated with the mating hole 110, so that after the internal spline 2 in the shaft extension part 1 is heat-treated, the internal spline 2 can be machined twice by the method of secondary hard drawing and finishing, solving the problem that the internal spline in the blind hole at the shaft end cannot be machined with high precision after heat treatment, improving the accuracy of the tooth profile parameters of the internal spline shaft, and being able to ensure the national standard 6-level accuracy of the internal spline. The process is conventional and highly operable.

[0023] The shaft extension part 1 in this embodiment includes a front shaft section 11, a middle platform section 12, and a rear shaft section 13. Among them, the front shaft section 11 and the rear shaft section 13 are respectively fixed on both sides of the middle platform section 12, and the diameter of the middle platform section 12 is greater than the diameters of the front shaft section 11 and the rear shaft section 13; the mating hole 110 is opened on the side of the rear shaft section 13 away from the middle platform section 12, and a through hole 120 is opened on the side of the rear shaft section 13 close to the front shaft section 11. The front end hole 100 is arranged on one side of the front shaft section 11, and the through hole 120 is communicated with the front end hole 100 and the mating hole 110; the front shaft section 11, the middle platform section 12, and the rear shaft section 13 are of an integrally formed structure.

[0024] It should be noted that the internal spline 2 is arranged in the front shaft section 11. The internal spline 2 is mainly used to transmit torque. At the same time, the improvement of the accuracy of the internal spline 2 is beneficial to reducing the angular error during the transmission of the internal and external splines, reducing the spline transmission clearance and the side clearance variation, thereby reducing the transmission noise; while heat treatment will make the tooth profile parameter accuracy of the internal spline 2 in the front end hole 100 of the shaft end worse, so the internal spline 2 after heat treatment needs to be subjected to secondary finishing. Therefore, the through hole 120 is provided, and the through hole 120 is used to avoid the broaching tool during the secondary broaching finishing; and the through hole 120 is communicated with the front end hole 100 and the mating hole 110 to facilitate the secondary finishing of the internal spline 2 after heat treatment.

[0025] It can be understood that the size of the through hole 120 can vary according to the motor cooling requirements. For a motor without liquid cooling circulation in the rotor, the smaller the size of the through hole 120, the better, and the less grease is required to fill the through hole 120; for a motor with liquid cooling circulation in the rotor, the size of the through hole 120 can be designed according to the cooling flow requirements, or spray holes can be designed around the through hole 120.

[0026] Moreover, the integrally formed structure of the shaft extension part 1 eliminates the connection gaps and potential failure points between various parts, making the shaft extension part 1 more solid and durable as a whole, capable of withstanding greater forces and torques, and improving the stability and reliability of the motor.

[0027] The through hole 120, the front end hole 100, and the mating hole 110 in this embodiment are combined to form an inner cavity 130. The inner cavity 130 is filled with grease. A grinding wheel run-out groove 140 is opened on the inner wall of the mating hole 110 for tightly fitting the non-shaft extension part 3 with the mating hole 110 to seal one side of the inner cavity 130.

[0028] It should be noted that the mating hole 110 is used for assembling the non-axially extending portion 3. The inner wall of the mating hole 110 is provided with a grinding wheel run-out groove 140, which enables it to more easily enter the mating hole 110 for precise grinding after heat treatment, thereby improving the machining accuracy of the mating hole 110, helping to ensure the tight fit between the non-axially extending portion 3 and the axially extending portion 1, further ensuring the coaxiality of the two segmented shafts, and at the same time ensuring the airtightness of the connection, avoiding problems such as liquid leakage or grease leakage.

[0029] This embodiment further includes a mating part 4 and a sealing part 5. Among them, the mating part 4 is arranged in the front-end hole 100, and the mating part 4 meshes with the internal spline 2 for transmitting torque to the mating part 4; the sealing part 5 is sleeved on the outside of the mating part 4 and abuts against the inner wall of the front-end hole 100 for sealing the other side of the inner cavity 130.

[0030] It should be noted that the mating part 4 extends into the front-end hole 100 and meshes with the internal spline 2, enabling torque to be transmitted to the mating part 4, and then transmitted to other transmission components through the mating part 4. The sealing part 5 is sleeved on the outside of the mating part 4 and abuts against the inner wall of the front-end hole 100, effectively sealing the other side of the inner cavity 130, preventing the leakage of lubricating grease and the entry of external contaminants, not only improving the overall performance of the motor but also extending its service life.

[0031] This embodiment further includes at least two bearings 101. Among them, at least two bearings 101 are respectively arranged on the outside of the non-axially extending portion 3 and the front shaft section 11, and one side bearing 101 abuts against the middle platform section 12, and the other side bearing 101 abuts against the end face of the rear shaft section 13 for supporting the entire motor shaft.

[0032] This embodiment further includes two magnetic separation parts 6, several rotor cores 7 and fasteners 8. Among them, both of the two magnetic separation parts 6 are sleeved on the outside of the rear shaft section 13 and are arranged at intervals, and one side magnetic separation part 6 abuts against the middle platform section 12; several rotor cores 7 are all sleeved on the outside of the rear shaft section 13, and several rotor cores 7 are arranged in sequence and abut between the two magnetic separation parts 6; the fastener 8 is fixed on the outside of the rear shaft section 13 and abuts against the other side magnetic separation part 6 for pressing the position of the rotor core 7.

[0033] It should be noted that both of the two magnetic separation parts 6 are sleeved on the outside of the rear shaft section 13 and are arranged at intervals, and one side magnetic separation part 6 abuts against the middle platform section 12 as the starting position of the rotor core 7, and the positions of several rotor cores 7 are limited between the two magnetic separation parts 6 by the fastener 8.

[0034] Inside the rotor core 7 in this embodiment, a number of first protrusion parts 71 extending towards the axis are provided; on the outer side of the rear shaft section 13, a number of first key grooves 150 are opened. The number and positions of the first key grooves 150 are correspondingly arranged with those of the first protrusion parts 71. And the first protrusion parts 71 are abutted in the first key grooves 150, and the outer contour shape of the first protrusion parts 71 matches the inner contour shape of the first key grooves 150, which is used to transmit the torque generated by the motor.

[0035] It should be noted that in order to cooperate with the first protrusion parts 71 of the rotor core 7, a number of first key grooves 150 with the number and positions corresponding to those of the first protrusion parts 71 one by one are designed on the outer side of the rear shaft section 13, ensuring that each first protrusion part 71 can be accurately embedded into a first key groove 150, thus forming a stable mechanical connection. Moreover, the outer contour shape of the first protrusion parts 71 coincides with the inner contour shape of the first key grooves 150, which not only enhances the stability of the connection, but also effectively reduces the friction and wear caused by shape mismatch, thereby extending the service life of the motor. At the same time, the number of first protrusion parts 71 and first key grooves 150 are symmetrically distributed, which can effectively transmit the torque generated by the motor.

[0036] It can be understood that for a motor with a small torque, the rotor core 7 and the rear shaft section 13 can also be in interference fit to transmit the motor torque, without designing the first key grooves 150 and first protrusion parts 71.

[0037] On the non - shaft - extension part 3 in this embodiment, a boss part 31 is provided, and the boss part 31 is arranged on the side away from the shaft - extension part 1. On the end face of the non - shaft - extension part 3 away from the shaft - extension part 1, a threaded hole 300 is opened. On the outer side of the boss part 31, a second key groove 310 is opened. On the inner side of the resolver rotor, a second protrusion part 9 extending towards the axis is provided. The resolver rotor is sleeved on the outer side of the boss part 31, and the second protrusion part 9 is abutted in the second key groove 310. A compression screw 10 is threadedly connected in the threaded hole 300, and the end of the compression screw 10 abuts against the resolver rotor to lock the resolver rotor and the non - shaft - extension part 3.

[0038] It should be noted that the second key groove 310 is provided for positioning the resolver rotor, and the circumferential direction of the second key groove 310 needs to be fixed with the circumferential direction of the first key groove 150 of the shaft - extension part 1 to ensure that the initial zero position of the resolver is relatively fixed. And the compression screw 10 is provided for fixing the resolver rotor.

[0039] It can be understood that for a small motor, an interference fit method can also be directly adopted. After the non - shaft - extension part 3 is liquid - cooled, it is directly inserted into the resolver rotor, canceling the threaded hole 300, the second key groove 310 and the second protrusion part 9. An additional tooling is required to position the relative positions of the resolver rotor and the motor rotor.

[0040] In this embodiment, a center hole 102 is provided on the side of the non-axial extension portion 3 away from the threaded hole 300, the front end hole 100, the matching hole 110 and the opening of the threaded hole 300 for positioning the ejector pin during machine tool processing. It can also serve as a guide during parts assembly to facilitate installation.

[0041] In a second aspect, the present invention further provides a new energy motor shaft processing process, using the new energy motor shaft as described above, comprising the following steps: S1: Clamp the shaft extension part 1 and the non-shaft extension part 3 on the machine tool chuck respectively, drill center holes 102 at both ends of the shaft extension part 1 and the non-shaft extension part 3 respectively, which are used as machining positioning references, and drill the front end hole 100, the matching hole 110 and the through hole 120 on the shaft extension part 1, and drill the threaded hole 300 on the non-shaft extension part 3; S2: Use a pin to push up each center hole 102, and finish turning all cylindrical surfaces, so that the shaft extension part 1 forms a front shaft section 11, a middle platform section 12 and a rear shaft section 13, and a boss section 31 is formed on the non-shaft extension part 3, so as to improve the matching accuracy and ensure the matching accuracy of the two shaft sections and the air tightness at the matching surface; S3: milling the shaft extension part 1 and the non-shaft extension part 3 using a milling machine to generate a first keyway 150 and a second keyway 310 respectively; S4: Clamp the shaft extension 1 on the chuck of the machine tool, and use a gear shaping machine to perform gear shaping to form an internal spline 2. The spindle stroke number is set to 150-200 str / min, and at least 5 feeds are used in the radial direction. The feed amount and feed speed are gradually reduced, and the time is 6-10 minutes. S5: Put the shaft extension part 1 and the non-shaft extension part 3 into a carburizing furnace for carburizing treatment, the heat treatment temperature is 860-900°C, and the surface hardness after carburizing reaches 56-62HRC; S6: Grinding each center hole 102 using a grinder; S7: Clamp the shaft extension 1 on the hard gear drawing equipment, use a carbide broach to perform secondary finishing on the internal spline, and at the same time, finish the internal spline tooth shape and the internal spline minor diameter. The broaching speed is controlled at 40~100m / min, and the broaching stroke generally only takes 1~2 seconds. The roughness Ra is ≤1.6μm, and the single-side tooth thickness allowance for broaching is 0.018mm; the cross-bar distance variation is ≤0.03mm; the single-side broaching allowance for major and minor diameters is 0.06mm; At present, the new energy industry has relatively high requirements for the internal spline tooth profile parameters (such as tooth profile, tooth direction, cumulative pitch tolerance, etc.) and the radial runout accuracy of the tooth ring; in the mainstream processing technology, carburizing high-temperature heat treatment will cause the deterioration of the internal spline tooth profile parameters and the radial runout accuracy of the tooth ring. Even by improving the accuracy of the tooth profile parameters before heat treatment (at present, the tooth profile parameters before heat treatment in the industry can reach level 5 required by GB / T 3478.1-2008, and some can even reach level 4 accuracy), it is still impossible to batch ensure that the tooth profile parameters and the radial runout accuracy of the tooth ring after heat treatment meet the 6th level tolerance accuracy required by GB / T 3478.1-2008. At the same time, the gear shaper does not have the function of secondary tool setting and cannot accurately position for secondary finishing of the internal spline, and cannot perform secondary processing. The surface finish of the spline is also not good. Therefore, a secondary finishing process of hard drawn teeth is proposed for the blind hole internal spline motor shaft in this embodiment. To implement this processing technology, the structure of the motor shaft is designed in sections.

[0042] Among them, the hard drawing process uses a hard broach for finishing after heat treatment. Because it can completely remove the heat treatment deformation of the machining object with a hardness of 50-62 HRC, it can finish machining the internal spline that was difficult to machine before. Therefore, it can achieve high precision and stability of parts, shorten the processing cycle and save energy, greatly improve the mechanical rigidity and the broach retention, the simple design realizes high-precision assembly accuracy, realizes a model of high-hardness material processing technology, and realizes high precision and long life through the development of high-speed broaches; Secondary hard drawn tooth finishing for the shaft extension part of the shaft; using a special hard drawn tooth equipment, through the precise positioning of the external spline of the front guide sleeve meshing with the internal spline of the product, a cemented carbide broach is used for secondary finishing of the internal spline; it can simultaneously finish machining the tooth profile of the internal spline and the minor diameter of the internal spline. The secondary finishing of the minor diameter can ensure the higher coaxiality requirement between the spline pitch circle and the minor diameter, and can achieve the requirement of the minor diameter of the internal spline with IT9 level dimensional accuracy. After hard drawing the minor diameter of the spline, it can be used as a positioning reference surface for machining the outer circle and the end face, realizing the higher runout requirement of the positioning reference surface for the spline pitch circle and eliminating the shape error of heat treatment.

[0043] S8: Clamp the shaft extension part 1, use the minor diameter of the internal spline 2 for positioning, and grind the installation position of the bearing 101 and the outer wall of the shaft extension part 1; for the non-shaft extension part 3, use the center hole 102 for positioning and grind the installation position of the bearing 101. S9: Install a lifting ring screw at the tail end of the non-shaft extension part 3 to cooperate with the threaded hole 300, use a lifting hook to put the non-shaft extension part 3 into the liquid nitrogen tank, set the cooling temperature to -150±10°C, and the cooling time is 10-20 seconds. After cooling is completed, use a lifting hook to take out the non-shaft extension part 3 from the liquid nitrogen tank and directly install it into the mating hole 110 on the shaft extension part 1 for interference fit to prevent frostbite. The interference amount is between 0.01 and 0.03 mm. Wait for the temperature to return to normal to complete the machining and assembly of the motor shaft.

[0044] Since the motor torque is transmitted to the internal spline 2 at the end of the shaft extension part 1 through the cooperation of the first protrusion 71 of the rotor and the first keyway 150, rather than the shaft extension part 3 only playing a supporting role; therefore, the non-shaft extension part 3 and the shaft extension part 1 are assembled by the liquid cooling method to ensure a relatively precise connection. At the same time, the liquid cooling method assembly does not carry the risk of damaging the material.

[0045] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A new energy motor shaft, characterized in that: It comprises a shaft extension portion (1), an internal spline (2) and a non-shaft extension portion (3), wherein: A front end hole (100) is provided on one side of the shaft extension portion (1), and a matching hole (110) is provided on the other side, and the front end hole (100) is communicated with the matching hole (110); The internal spline (2) is arranged in the front end hole (100), and the axes of the internal spline (2), the front end hole (100) and the matching hole (110) are all on the same axis, so as to transmit torque outwards; The non-axial extension portion (3) is interference-fitted in the matching hole (110) and is used to seal one side of the front end hole (100), and one end of the non-axial extension portion (3) away from the axial extension portion (1) is fixed to the rotary rotor.

2. The new energy motor shaft according to claim 1, characterized in that: The axle extension (1) comprises a front axle section (11), a middle platform section (12) and a rear axle section (13), wherein: The front axle section (11) and the rear axle section (13) are respectively fixed on both sides of the middle platform section (12), and the diameter of the middle platform section (12) is larger than the diameters of the front axle section (11) and the rear axle section (13); The matching hole (110) is provided on a side of the rear axle section (13) away from the middle platform section (12), and a through hole (120) is provided on a side of the rear axle section (13) close to the front axle section (11); the front end hole (100) is provided on a side of the front axle section (11), and the through hole (120) is connected to the front end hole (100) and the matching hole (110); The front axle section (11), the middle platform section (12) and the rear axle section (13) are an integrally formed structure.

3. The new energy motor shaft according to claim 2, characterized in that: The through hole (120), the front end hole (100) and the matching hole (110) are combined to form an inner cavity (130), the inner cavity (130) is filled with lubricating grease, and the inner wall of the matching hole (110) is provided with a grinding wheel overtravel groove (140) for tightly fitting the non-axial extension portion (3) with the matching hole (110) to seal one side of the inner cavity (130).

4. The new energy motor shaft according to claim 3, characterized in that: It also includes a matching component (4) and a sealing component (5), wherein the matching component (4) is arranged in the front end hole (100), and the matching component (4) is meshed with the internal spline (2) for transmitting torque to the matching component (4); the sealing component (5) is sleeved on the outside of the matching component (4) and abuts against the inner wall of the front end hole (100) for sealing the other side of the inner cavity (130).

5. The new energy motor shaft according to claim 2, characterized in that: It also includes at least two bearings (101), wherein the at least two bearings (101) are respectively arranged on the outside of the non-axle extension portion (3) and the front axle section (11), and one side bearing (101) abuts against the middle platform section (12), and the other side bearing (101) abuts against the end surface of the rear axle section (13), so as to support the entire motor shaft.

6. The new energy motor shaft according to claim 2, characterized in that: It also includes two magnetic spacers (6), a plurality of rotor cores (7) and fasteners (8), wherein: The two magnetic spacers (6) are both sleeved on the outside of the rear axle section (13) and are arranged at intervals, and the magnetic spacer (6) on one side abuts against the middle platform section (12); The plurality of rotor cores (7) are sleeved on the outside of the rear shaft section (13), and the plurality of rotor cores (7) are arranged in sequence and abut against two magnetic spacers (6); The fastener (8) is fixed to the outside of the rear shaft section (13) and abuts against the magnetic separator (6) on the other side, and is used to press the position of the rotor core (7).

7. The new energy motor shaft according to claim 6, characterized in that: The inner side of the rotor core (7) is provided with a plurality of first protrusions (71) extending toward the axis; the outer side of the rear shaft section (13) is provided with a plurality of first key slots (150), the number and positions of the first key slots (150) are arranged corresponding to the first protrusions (71), the first protrusions (71) abut against the inside of the first key slots (150), and the outer contour shape of the first protrusions (71) matches the inner contour shape of the first key slots (150), so as to transmit the torque generated by the motor.

8. The new energy motor shaft according to claim 2, characterized in that: A boss portion (31) is provided on the non-axial extension portion (3), and the boss portion (31) is arranged on a side away from the axial extension portion (1); a threaded hole (300) is provided on an end surface of the non-axial extension portion (3) on a side away from the axial extension portion (1); a second keyway (310) is provided on the outer side of the boss portion (31); a second protrusion (9) extending toward the axis is provided on the inner side of the rotary rotor; the rotary rotor is sleeved on the outer side of the boss portion (31), and the second protrusion (9) abuts against the second keyway (310); a clamping screw (10) is threadedly connected to the inner thread of the threaded hole (300); the end of the clamping screw (10) abuts against the rotary rotor, thereby locking the rotary rotor and the non-axial extension portion (3).

9. The new energy motor shaft according to claim 8, characterized in that: A side of the non-axial extension portion (3) away from the threaded hole (300), the front end hole (100), the matching hole (110) and the opening of the threaded hole (300) are all provided with a center hole (102) for positioning an ejector pin during machine tool processing.

10. A new energy motor shaft processing technology, using the new energy motor shaft according to any one of claims 1-9, characterized in that: The following steps are involved: S1: Clamp the shaft extension part (1) and the non-shaft extension part (3) on a machine tool chuck respectively, drill center holes (102) at both ends of the shaft extension part (1) and the non-shaft extension part (3) respectively to serve as a machining positioning reference, drill a front end hole (100), a matching hole (110) and a through hole (120) on the shaft extension part (1), and drill a threaded hole (300) on the non-shaft extension part (3); S2: Using a pin to push against each center hole (102) respectively, and finishing turning all cylindrical surfaces, so that the shaft extension part (1) forms a front shaft section (11), a middle platform section (12) and a rear shaft section (13), and a boss section (31) is formed on the non-shaft extension part (3); S3: using a milling machine to mill the shaft extension portion (1) and the non-shaft extension portion (3) to generate a first keyway (150) and a second keyway (310), respectively; S4: Clamp the shaft extension (1) on the chuck of the machine tool, and use a gear shaping machine to perform gear shaping to form an internal spline (2). The spindle stroke number is set to 150-200 str / min, and at least 5 feeds are used in the radial direction. The feed amount and feed speed are gradually reduced, and the time is 6-10 minutes. S5: placing the shaft extension part (1) and the non-shaft extension part (3) in a carburizing furnace for carburizing treatment at a heat treatment temperature of 860-900° C., and making the surface hardness reach 56-62 HRC after carburizing; S6: grinding each center hole (102) using a grinder; S7: Clamp the shaft extension (1) on the hard gear drawing equipment, use a carbide broach to perform secondary finishing on the internal spline, and simultaneously finish the internal spline tooth shape and internal spline minor diameter. The broaching speed is controlled at 40-100 m / min. The broaching stroke generally takes only 1-2 seconds. The roughness Ra is ≤1.6 μm, and the single-side tooth thickness allowance is 0.018 mm. The variation of the span distance is ≤0.03mm; the single-side allowance for large and small diameter broaching is 0.06mm; S8: clamping the shaft extension part (1), using the internal spline (2) for small diameter positioning, grinding the installation position of the bearing (101) and the outer wall of the shaft extension part (1); using the center hole (102) for positioning the non-shaft extension part (3), grinding the installation position of the bearing (101); S9: Install an eye screw at the rear end of the non-shaft extension part (3) to match the threaded hole (300), and use a hook to place the non-shaft extension part (3) into a liquid nitrogen box. Set the cooling temperature to -150±10℃ for 10 to 20 seconds. After cooling, use a hook to take out the non-shaft extension part (3) from the liquid nitrogen box and directly install it into the matching hole (110) on the shaft extension part (1) for interference fit. The interference amount is between 0.01 and 0.03 mm. When the temperature returns to normal, complete the processing and assembly of the motor shaft.

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