An assembly method for an EMB motor

Abstract

The present application relates to the technical field of EMB motor, and particularly relates to an assembling method of EMB motor, which comprises the following steps: heating the front end cover shell and then hot fitting it on the stator assembly, so that the stator core is pushed to the limiting protrusion in the front end cover shell, and the copper bar on the stator assembly is pulled out from the wire hole of the front end cover shell; placing the front bearing into the front bearing chamber, and then riveting the cover plate to the front end cover shell through riveting tool; clamping the rotor assembly by the rotor assembling tool, and then pressing the rotor assembly into the stator assembly, and then pressing the gear set and the magnetic drag assembly into the front shaft of the rotor assembly; sleeving the rear bearing into the rear shaft of the rotor assembly, and then placing the wave spring into the rear end cover, and then pressing the rear end cover into the front end cover shell through the rear end cover assembling tool and gluing. The present application improves the assembling precision of the EMB motor, and improves the structural strength and reliability of the EMB motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of EMB motor, and particularly relates to an assembling method of EMB motor. BACKGROUND

[0002] As the core executive component of the brake-by-wire system, the EMB (electronic mechanical brake) motor is designed with full electronic without hydraulic pipeline, and realizes braking by directly driving the brake caliper through the motor. The structure of the motor generally comprises a stator, a rotor, a reducer and a control unit. The EMB motor is widely used in new energy vehicles, rail transit and aviation fields due to the advantages of full electronic control, extremely fast response speed and high precision control.

[0003] However, the front end cover flange and the shell of the existing EMB motor are in a split structure, and the shell and the rear end cover are in an integrated structure. The assembling process is that the rotor assembly is first assembled with the front end cover flange, the stator assembly is pressed into the shell, the wave spring is placed in the rear bearing chamber of the shell, the rotor front end cover assembly is pressed into the stator shell assembly, and finally the sealant is applied at the joint between the front end cover flange and the shell. This assembling method has the following shortcomings:

[0004] 1. The front end cover flange and the shell are in a split structure, and there is a concentricity error between the two during assembly;

[0005] 2. The stator assembly is pressed into the shell, and the shell bottom is limited by the boss. Since the axial size precision requirement of the busbar three-phase pin to the front end cover flange is relatively high, this assembling method will add the length tolerance of the stator core, and the size tolerance of the busbar three-phase pin to the front end cover flange cannot meet the high precision size requirement;

[0006] 3. The shell and the rear end cover are in an integrated structure, and the rear shaft cannot be positioned during assembly, but only positioned by the front flange at one end. The permanent magnet on the rotor will be magnetically attracted to the inner hole of the stator core, and the rotor will be attracted to any side of the inner hole of the stator during assembly, which cannot meet the concentric assembly. The rear bearing of the rotor is hard pressed into the front flange end face by the press, and the risk of bearing bruising is extremely high. Moreover, the front flange and the shell are prone to extrusion during assembly, which will generate aluminum chips. The aluminum chips dropped into the motor will cause abnormal noise of the motor. SUMMARY

[0007] The application solves the problems in the related art, and provides an assembling method of an EMB motor, a front end cover shell is integrally formed, and a rear end cover is connected with the front end cover in a detachable manner, so that the assembling of the EMB motor can be performed from front to back, thereby facilitating the control of the assembling height of a stator assembly and copper bars thereof, improving the assembling precision of the EMB motor, facilitating the installation of a rear bearing, avoiding the risk of bruising of the rear bearing during assembling, the front end cover is integrally formed with the shell, the concentricity of a front end cover flange stop, a front end cover bearing chamber, an inner diameter of the shell and an inner stop of the shell can be improved, the risk of loosening is eliminated, and the size precision of a rotating shaft and the length size precision of a three-phase power Pin are improved; the limiting protrusion on the inner wall of the shell is used for limiting, the axial size of the stator assembly is ensured, and the assembling precision is ensured.

[0008] In order to solve the above technical problems, the application is realized by the following technical scheme: an assembling method of an EMB motor, steps are as follows:

[0009] S1, the stator assembly is pressed into the front end cover shell: the stator assembly is placed on the tool base, and then the front end cover shell is heated and is hot-mounted on the stator assembly, so that the stator core is pressed to the limiting protrusion in the front end cover shell, and the copper bars on the stator assembly are pulled out from the wire hole of the front end cover shell;

[0010] S2, front bearing installation and riveting: the front bearing is placed in the front bearing chamber, and then the cover plate is riveted to the front end cover shell through the riveting tool;

[0011] S3, rotor assembly, gear set and magnetic drag assembly pressing: the rotor assembly is clamped by the rotor assembly tool and is pressed into the stator assembly, and the gear set and the magnetic drag assembly are sequentially pressed into the front shaft of the rotor assembly;

[0012] S4, rear end cover assembling: the rear bearing is sleeved on the rear shaft of the rotor assembly, the wave spring is placed in the rear end cover, and the rear end cover is pressed into the front end cover shell by the rear end cover assembling tool and is glued.

[0013] As a preferred scheme, in the step S1, a positioning groove is formed in the limiting protrusion, and the pin of the stator assembly is inserted into the positioning groove.

[0014] As a preferred scheme, in the step S2, the front end cover shell is formed with a front bearing chamber, a counterbore is formed above the front bearing chamber, the front bearing is assembled in the front bearing chamber and is pressed by the cover plate riveted on the counterbore.

[0015] As a preferred scheme, the rotor assembly tooling comprises a first upper pressing plate, a first lower bottom plate and a first middle layer plate, the first upper pressing plate is provided with a first pressing head, the first middle layer plate is provided with a vertical plate and the vertical plate is provided with a clamping head for clamping the front end cover shell and a magnetic attraction head for magnetically attracting the rotor assembly, the first middle layer plate is provided with a positioning hole and a positioning pin for positioning the front end cover shell, the first lower bottom plate is provided with a lifting guide rod which extends from the first middle layer plate and is positioned relative to the rotor assembly, a first guide column passes through the first upper pressing plate, the first middle layer plate and the first lower bottom plate, and the first upper pressing plate and the first lower bottom plate are simultaneously pressed downward to press the rotor assembly into the stator assembly.

[0016] As a preferred scheme, in step S3, when the rotor assembly is assembled, the assembled front end cover shell is positioned by the positioning pin and clamped by the clamping head, the rotor assembly is magnetically attracted by the magnetic attraction head, the lifting guide rod is lifted to pass through the shaft hole on the front end cover shell and position the front shaft of the rotor assembly, the first upper pressing plate drives the first pressing head and the first lower bottom plate drives the lifting guide rod to simultaneously press downward, so that the rotor assembly is pressed into the stator assembly.

[0017] As a preferred scheme, the rear end cover assembly tooling comprises a second upper pressing plate, a second lower bottom plate and a second middle layer plate, the second upper pressing plate is provided with a second pressing head, and a second guide column passes through the second upper pressing plate, the second middle layer plate and the second lower bottom plate.

[0018] As a preferred scheme, in step S4, when assembled, the rear end cover is placed in the placing groove, the wave spring and the rear bearing are sequentially placed in the rear end cover, the front end cover shell assembly assembled in step S3 is placed in the placing hole of the second middle layer plate and positioned by the positioning pin, and the second pressing head is driven by the servo press to press downward, so that the rear end cover and the front end cover shell assembly are pressed together.

[0019] As a preferred scheme, in step S4, the rear end cover is provided with a plurality of protrusions distributed on the stop opening, the end of the protrusion has a taper, the front end cover is provided with a third groove corresponding to the position of the protrusion, and the protrusion is clamped into the third groove; at least one side of the bottom of the protrusion is provided with a first groove, a second groove is formed on the rear end cover of the outer ring of the protrusion, and the third groove and / or the second groove is glued.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] (1) The front end cover shell of the present application is integrally formed, and the rear end cover and the front end cover are connected in a detachable manner, so that the assembly of the EMB motor can be carried out from front to back, thereby facilitating the control of the assembly height of the stator assembly and the copper bar, and improving the assembly precision of the EMB motor.

[0022] (2) The present invention uses the limiting protrusion on the inner wall of the housing to limit the axial dimension of the stator assembly press-fit, ensure the assembly accuracy, eliminate the assembly tolerance of the iron core, and thus reduce the assembly tolerance of the three-phase power supply pin at the end of the busbar.

[0023] (3) The front cover and the housing are integrally formed, which can improve the concentricity of the front cover flange stop, the front cover bearing chamber, the inner diameter of the housing and the inner stop of the housing, and there is no risk of loosening. It improves the dimensional accuracy of the shaft output shaft and the dimensional accuracy of the three-phase power supply pin length, which facilitates the serial development of motors on this platform, saves mold costs and reduces development costs. The integral flange stop of the front cover has higher strength and reliability than the split structure. The front cover flange housing and the rear cover are detachably connected, which facilitates the installation of the rear bearing and avoids damage to the rear bearing due to the inability to be aligned during assembly. Moreover, the wires exit from the front cover, making the overall structure more compact.

[0024] (4) The rear bearing is mounted on the rear shaft of the rotor assembly and the end of the rear shaft is flush with the rear bearing. The rear bearing is mounted inside the rear end cover, which makes the overall axial dimension of the EMB motor more compact.

[0025] (5) The front bearing is assembled in the bearing chamber of the front cover. The cover plate is riveted to the top of the bearing chamber by the riveting fixture, so that the cover plate presses the outer ring of the bearing to prevent the bearing from running out of the outer ring. This design avoids the riveting head directly riveting to the bearing and causing bearing damage. The riveting pressure can be controlled more precisely to avoid insufficient riveting and to prevent the bearing from running out of the outer ring after a long period of operation.

[0026] (6) After the rear end cover is pressed into the housing, the protrusion is stuck in the third groove, thereby preventing the rear end cover from coming loose, improving assembly efficiency and reducing costs; the second groove and / or the third groove are glued to improve the waterproof rating and sealing performance; in addition, the design of the second groove can also avoid stress concentration when the protrusion is pressed in, which may cause cracking.

[0027] (7) During rotor assembly, the rotor assembly is positioned by lifting guide rod, and then the rotor assembly and lifting guide rod are pressed down simultaneously by servo press to realize the assembly of rotor assembly. The assembly process is simple and precise. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the EMB motor of the present invention;

[0029] Figure 2 This is an exploded view of the present invention;

[0030] Figure 3 This is a cross-sectional view of the EMB motor of the present invention;

[0031] Figure 4 This is the present invention. Figure 3 Enlarged view of point A in the middle;

[0032] Figure 5 is a magnified view of B of the present application Figure 3

[0033] Figure 6 is a structural schematic view of the front end cover shell of the present application

[0034] Figure 7 is a sectional view of the front end cover shell of the present application

[0035] Figure 8 is a structural schematic view of the rear end cover of the present application

[0036] Figure 9 is a structural schematic view of the stator assembly of the present application

[0037] Figure 10 is a structural schematic view of the rotor assembly tooling of the present application

[0038] Figure 11 is a schematic view of the rotor assembly on tooling of the present application

[0039] Figure 12 is a structural schematic view of the rear end cover assembly tooling of the present application

[0040] Figure 13 is a schematic view of the rear end cover assembly of the present application

[0041] In the figure:

[0042] 1, housing assembly, 101, front end cover, 1011, wire hole, 1012, front bearing chamber, 1013, cover plate, 1014, counterbore, 102, shell, 1021, limiting protrusion, 1022, positioning groove, 1023, third groove, 103, rear end cover, 1031, protrusion, 1032, first groove, 1033, second groove, 2, front bearing, 3, stator assembly, 301, busbar, 3011, copper bar, 3012, pin, 302, stator core, 4, rotor assembly, 5, gear set, 501, first gear, 502, second gear, 6, magnetic drag assembly, 7, rear bearing, 8, rotor assembly tooling, 801, first upper pressing plate, 802, first lower pressing plate, 803, first middle layer plate, 804, first pressing head, 805, vertical plate, 806, clamping head, 807, magnetic suction head, 808, lifting guide rod, 809, first guide column, 9, rear end cover assembly tooling, 901, second upper pressing plate, 902, second lower bottom plate, 903, second middle layer plate, 904, second pressing head, 905, second guide column, 10, wave spring DETAILED DESCRIPTION

[0043] ​Clearly, the embodiments described are only some embodiments of the application and not all embodiments of the application. The descriptions of the at least one example embodiment are intended to be illustrative, and not to be limiting. Many variations to the example embodiments will be readily apparent to those skilled in the art from the embodiments described herein, and the entirety of this application, including claim language, should not be construed as limiting the application to any one or more of the example embodiments described herein.

[0044] It is to be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting of the example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0045] The relative arrangement of components and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless otherwise specifically stated. It is to be understood that the drawings are not necessarily to scale as the dimensions of the parts are for the clarity of presentation and therefore should not be interpreted as limiting. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail because they would be understood that such techniques, methods, and apparatus are considered part of the art. In all examples shown and discussed herein, any specific values are to be interpreted as illustrative only and not as a limitation. Other examples of the example embodiments can therefore have different values. It is to be noted that like reference numerals and letters refer to like items in the drawings and, as a result, further discussion of such items is not necessary in the subsequent drawings.

[0046] In the description of the application, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicated orientation or position relationship are generally based on the orientation or position relationship shown in the drawings, only for the convenience of describing the application and simplifying the description, without the opposite indication, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore, it cannot be understood as a limitation on the scope of protection of the application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.

[0047] For ease of description, spatially relative terms, such as "on", "above", "at", "below", "down", "up", "top", "bottom", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0048] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not have a special meaning and are only used to distinguish corresponding parts, and therefore cannot be understood as limiting the scope of protection of the present application.

[0049] As shown in the figure, an assembly method of an EMB motor is as follows: Figures 1-13

[0050] S1, press-fit the stator assembly 3 into the front end cover shell: place the stator assembly 3 on the tool base, then heat the front end cover shell and hot-fit it onto the stator assembly 3, so that the stator core 302 is on the limiting protrusion 1021 in the front end cover shell, and the copper bar 3011 of the stator assembly 3 passes through the wire hole 1011 (the tool used here is similar to the tool used for assembling the rear end cover), which ensures the axial size of the press-fit stator assembly 3 and the assembly accuracy, saves the assembly tolerance of the stator core 302, and thus reduces the assembly tolerance of the three-phase power Pin at the end of the bus bar 301;

[0051] S2, install and rivet the front bearing 2: place the front bearing 2 into the front bearing chamber 1012, and then rivet the cover plate 1013 to the front bearing chamber 1012 by riveting tool (here, it is a conventional riveting tool);

[0052] S3, press-fit the rotor assembly 4, gear set 5, and magnetic drag assembly 6: hold the rotor assembly 4 by the rotor assembly tool 8 and press it into the stator assembly 3, and then press the gear set 5 and the magnetic drag assembly 6 into the front shaft of the rotor assembly 4;

[0053] S4, assemble the rear end cover 103: fit the rear bearing 7 into the rear shaft of the rotor assembly 4 and flush with the rear shaft, then place the wave spring 10 into the rear bearing chamber of the rear end cover 103, and press the rear end cover 103 into the front end cover shell by the rear end cover assembly tool 9, and then coat sealant in the third groove 1023 and / or the second groove 1033.

[0054] ​The front end cover shell is integrally formed by the front end cover 101 and the shell 102, and the rear end cover 103 is detachably connected with the shell 102.

[0055] In one embodiment, in step S1, a positioning groove 1022 is formed on the limiting protrusion 1021, and in assembly, the pin 3012 of the stator assembly 3 is inserted into the positioning groove 1022.

[0056] In one embodiment, in step S2, a front bearing chamber 1012 is formed in the front end cover shell, a counterbore 1014 is formed above the front bearing chamber 1012, and the front bearing 2 is assembled in the front bearing chamber 1012 and is pressed by the cover plate 1013 on the counterbore 1014.

[0057] In one embodiment, the rotor assembly tool 8 includes a first upper pressing plate 801, a first lower bottom plate 802, and a first middle layer plate 803, the first upper pressing plate 801 is provided with a first pressing head 804, the first middle layer plate 803 is provided with a vertical plate 805, the lower part of the vertical plate 805 is provided with two clamping heads 806 for clamping the front end cover shell, the upper part of the vertical plate 805 is provided with a magnetic attraction head 807 for magnetically attracting the rotor assembly 4 (since the rotor assembly 4 has magnetism, the magnetic attraction head 807 can be made of magnetically conductive metal, and the front side of the magnetic attraction head 807 is in a V-shaped structure, which is convenient for positioning the rotor assembly 4), the first middle layer plate 803 is provided with a positioning hole and a positioning pin for positioning the front end cover shell, the first lower bottom plate 802 is provided with a lifting guide rod 808 extending from the first middle layer plate 803, and the lifting guide rod 808 is provided with a positioning hole, and a first guide column 809 passes through the first upper pressing plate 801, the first middle layer plate 803, and the first lower bottom plate 802, so that in assembly, the assembled front end cover shell is positioned by the positioning pin, clamped by the clamping head 806, and the rotor assembly 4 is magnetically attracted by the magnetic attraction head 807, the lifting guide rod 808 is lifted to pass through the shaft hole of the front end cover shell and position the front shaft of the rotor assembly 4, then the first upper pressing plate 801 drives the first pressing head 804 and the first lower bottom plate 802 drives the lifting guide rod 808 to press downward at the same time (a related driving mechanism such as a pneumatic cylinder can be used for driving), so that the rotor assembly 4 is pressed into the stator assembly 3.

[0058] In addition, in step S3, the gear set 5 includes a first gear 501 and a second gear 502, the first gear 501 is a helical gear, and the first gear 501, the second gear 502, and the magnetic drag assembly 6 are sequentially assembled on the front shaft of the rotor assembly 4.

[0059] In one embodiment, the rear end cover assembly tool 9 comprises a second upper pressing plate 901, a second lower bottom plate 902, and a second middle layer plate 903, the second upper pressing plate 901 is provided with a second pressing head 904, the second lower bottom plate 902 is provided with a placing groove for placing the rear end cover 103, and a second guide column 905 passes through the second upper pressing plate 901, the second middle layer plate 903, and the second lower bottom plate 902; when assembling, the rear end cover 103 is placed in the placing groove, the wave spring 10 and the rear bearing 7 are sequentially placed in the rear end cover 103, the assembled front end cover shell assembly is placed in the placing hole of the second middle layer plate 903 and positioned by the positioning pin, and the second pressing head 904 is driven to be pressed down by a servo press, so that the rear end cover 103 is pressed and combined with the front end cover shell assembly.

[0060] In one embodiment, in step S4, the rear end cover 103 is provided with four protrusions 1031 distributed on the stop portion, the end of the protrusion 1031 is provided with a taper, the shell 102 is provided with a third groove 1023 corresponding to the position of the protrusion 1031, the protrusion 1031 is clamped into the third groove 1023, and the stop portion of the protrusion 1031 is in interference fit with the shell 102, so as to realize the assembly of the rear end cover 103 and the shell 102; at least one side of the bottom of the protrusion 1031 is provided with a first groove 1032, the first groove 1032 can avoid stress concentration and cracking when the protrusion 1031 is pressed, and a second groove 1033 is formed around the protrusion 1031, and glue is injected in the third groove 1023 and / or the second groove 1033, so as to improve the sealing performance and waterproof performance.

[0061] The above is the preferred embodiment of the present application, and those skilled in the art can make changes and modifications to the above embodiment, therefore, the present application is not limited to the above specific embodiments, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present application shall fall within the protection scope of the present application.

Claims

1. A method of assembling an EMB electric machine, characterized by: The steps are as follows: S1, the stator assembly (3) is press-fitted into the front end cover shell: the stator assembly (3) is placed on the tool base, and then the front end cover shell is heated and is hot-fitted onto the stator assembly (3), so that the stator core (302) is topped to the limiting protrusion (1021) in the front end cover shell, and the copper bar (3011) on the stator assembly (3) is pulled out from the wire outlet hole (1011) of the front end cover shell; S2, front bearing (2) installation and riveting: the front bearing (2) is placed into the front bearing chamber (1012), and then the cover plate (1013) is riveted to the front end cover shell by the riveting tool; S3, rotor assembly (4), gear set (5) and magnetic drag assembly (6) press-fitting: the rotor assembly (4) is clamped by the rotor assembly (4) and is pressed into the stator assembly (3) through the rotor assembly (8), and the gear set (5) and the magnetic drag assembly (6) are pressed into the front shaft of the rotor assembly (4) in turn; S4, rear end cover (103) assembly: the rear bearing (7) is sleeved into the rear shaft of the rotor assembly (4), the wave spring (10) is placed into the rear end cover (103), and the rear end cover (103) is pressed into the front end cover shell and is glued by the rear end cover assembly tool (9), the rear end cover assembly tool (9) comprises a second upper pressing plate (901), a second lower bottom plate (902) and a second middle layer plate (903), the second upper pressing plate (901) is provided with a second pressure head (904), the second guide column (905) passes through the second upper pressing plate (901), the second middle layer plate (903) and the second lower bottom plate (902), the rear end cover (103) is provided with a plurality of protrusions (1031) on the stop opening, and the end of the protrusion (1031) has a taper, the front end cover shell is provided with a third groove (1023) corresponding to the position of the protrusion (1031), and the protrusion (1031) is clamped into the third groove (1023); at least one side of the bottom of the protrusion (1031) is provided with a first groove (1032), and a second groove (1033) is formed in the outer circle of the rear end cover (103) of the protrusion (1031), and the third groove (1023) and / or the second groove (1033) are glued.

2. The method of assembling an EMB electric machine according to claim 1, characterized in that: In the step S1, the limiting protrusion (1021) is provided with a positioning groove (1022), and the pin (3012) of the stator assembly (3) is inserted into the positioning groove (1022).

3. The method of assembling an EMB electric machine of claim 1, wherein: In the step S2, the front end cover shell is formed with a front bearing chamber (1012), a counterbore (1014) is formed above the front bearing chamber (1012), and the front bearing (2) is assembled in the front bearing chamber (1012) and is riveted to the counterbore (1014) to be compressed.

4. The method of assembling an EMB electric machine of claim 1, wherein: The rotor assembly tooling (8) comprises a first upper pressing plate (801), a first lower bottom plate (802) and a first middle layer plate (803), the first upper pressing plate (801) is provided with a first pressing head (804), the first middle layer plate (803) is provided with a vertical plate (805) and the vertical plate (805) is provided with a clamping head (806) for clamping the front end cover shell and a magnetic attraction head (807) for magnetically attracting the rotor assembly (4), the first middle layer plate (803) is provided with positioning holes and positioning pins for positioning the front end cover shell, the first lower bottom plate (802) is provided with a lifting guide rod (808) which extends from the first middle layer plate (803) and is positioned with the rotor assembly (4), a first guide column (809) passes through the first upper pressing plate (801), the first middle layer plate (803) and the first lower bottom plate (802), and the first upper pressing plate (801) and the first lower bottom plate (802) are simultaneously pressed downward to press the rotor assembly (4) into the stator assembly (3).

5. The method of assembling an EMB electric machine according to claim 4, characterized in that: In step S3, when the rotor assembly (4) is assembled, the assembled front end cover shell is positioned by the positioning pins and clamped by the clamping head (806), the rotor assembly (4) is magnetically attracted by the magnetic attraction head (807), the lifting guide rod (808) is lifted to pass through the shaft hole of the front end cover shell and position the front shaft of the rotor assembly (4), the first upper pressing plate (801) drives the first pressing head (804) and the first lower bottom plate (802) drives the lifting guide rod (808) to simultaneously press downward, so as to press the rotor assembly (4) into the stator assembly (3).

6. The method of assembling an EMB electric machine of claim 1, wherein: In step S4, when assembling, the rear end cover (103) is placed in the placing groove, the wave spring (10) and the rear bearing (7) are sequentially placed in the rear end cover (103), the front end cover shell assembly assembled in step S3 is placed in the placing hole of the second middle layer plate (903) and positioned by the positioning pins, the second pressing head (904) is driven by the servo press to press downward, so as to press the rear end cover (103) and the front end cover shell assembly.

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