electric machine

Abstract

This invention provides a motor in which a radial web is provided on the hole wall between the end face and the stop of the stator core. The difference between the distance from the inner end of the radial web to the core of the stator core and the radius of the rotor shaft is greater than or equal to the air gap between the rotor and the stator. Radial holes are formed on the rotor shaft, with at least three radial holes spaced circumferentially on the rotor shaft. Blind holes are formed on the rotor shaft, intersecting and communicating with the radial holes. A sliding column is provided within the radial holes, and a spring is provided on the rotor shaft. The spring provides elastic force to drive the sliding column to move towards the shaft core. The sliding column moves radially outward to a position where it abuts against the inner end of the radial web, and then moves radially inward to a position where it separates from the inner end of the radial web. This invention provides a radial web within the frame cavity, arranged axially between the end face and the stop of the stator core, thereby adjusting the rotor shaft core to a position coinciding with the core of the stator hole, solving the problem of the rotor and stator being difficult to separate due to strong magnetic attraction when composed of permanent magnet cores.

Description

Technical Field

[0001] This invention relates to the field of electric motors, specifically to an electric motor structure. Background Technology

[0002] Electric motors mainly include permanent magnet motors, which use permanent magnets to establish a magnetic field, and traditional electrically excited motors. Compared with the two, permanent magnet motors, especially rare earth permanent magnet motors, have significant advantages such as simple structure, reliable operation, small size, light weight, high power density, low loss, high efficiency, and flexible shape and size. Therefore, they are widely used, covering almost all fields of aerospace, defense, industrial and agricultural production, and daily life.

[0003] However, due to the inherent characteristics of permanent magnet motors, their production process is quite complex, especially the assembly of medium and large permanent magnet motors. The rotor has a strong magnetic field, and during the assembly process of the rotor being introduced into the stator, the stator and rotor are very easy to attract each other, causing collisions and deformation of the stator and rotor. Moreover, once the stator and rotor are attracted together, it is difficult to separate them. If the stator and rotor are not concentric, the end cover cannot be assembled. Only special mechanical equipment can be used for assembly, which is very inefficient.

[0004] Titled "Permanent Magnet Motor Assembly Fixture" (CN102170198A - hereinafter referred to as Document 1), Document 1 discloses a permanent magnet motor assembly fixture. It utilizes a rotor lifting device 11 to feed a rotor equipped with a lower rotor guide mold 5 and an upper rotor guide mold 6 into the cavity formed by a lower stator guide mold 3 and an upper stator guide mold 4. At this time, the support portion 30 of the lower stator guide mold 3 supports the lower end face of the lower rotor guide mold 5, providing support for the rotor. Furthermore, a stop 31 perpendicular to the support portion 30 positions the rotor horizontally, resulting in high assembly efficiency. While Document 1 solves the problem of rotor insertion into the stator, it avoids addressing the issues of maintaining the air gap between the rotor and stator after removing or disassembling the lower rotor guide mold 5, the upper rotor guide mold 6, and the rotor being fed into the lower stator guide mold 3 and the upper stator guide mold 4, as well as the assembly of the motor end cover with the stator. In other words, Document 1 only solves the process of rotor insertion into the stator and does not provide a solution for assembling the motor end cover.

[0005] The device, titled "Assembly and Disassembly Device for Radial Permanent Magnet Motor Stator and Rotor" (CN 107453561 A - hereinafter referred to as Document 2), first connects the front end cover 13 to the housing 12 with the stator using 3 or 4 bolts. The rotor positioning plate 6 is moved to the top of the guide rail. The lifting platform 2 pushes the extension shaft 3 upward until the upper end of the extension shaft 3 is higher than the upper end of the housing 12 with the stator. The rear end cover 9 of the motor and the rotor 10 are vertically moved with the shaft raised downwards to directly above the extension shaft 3. The mating stop e 8 of the rear end cover 9 mates with the positioning through hole d 20 of the rotor positioning plate 6. The bolts are connected to the internal threads on the rear end cover after passing through the connecting through hole c. The rear end cover 9 and the rotor 10 of the motor are fixed under the rotor positioning plate 6. The extension shaft 3 is rotated to connect with the motor shaft. At this point, the elevator 2 descends, and the rotor positioning plate 6, rear end cover 9, rotor 10, and shaft 11 move downwards as a whole due to gravity. A downward force can be applied manually until the motor rotor 10 is fully inserted into the stator 12. The rear end cover 9 is then bolted to the stator-containing housing 12. The connecting bolts between the mounting platform 4 and the front end cover 13, and between the rotor positioning plate 6 and the rear end cover 9, are then removed, completing the motor assembly process. It is evident that document 2 achieves simultaneous rotor insertion and end cover installation, making it a feasible installation fixture for permanent magnet motors. The drawback of document 2 is that appropriate tooling is required to assemble and disassemble the motor.

[0006] The difficulty in assembling permanent magnet motors also poses significant challenges to after-sales maintenance. Once a motor leaves the factory, minor problems during use cannot be disassembled and repaired on-site by after-sales personnel. It must be returned to the company and disassembled using specialized tools. Furthermore, it is impractical for motor users to have the tooling and other specialized equipment disclosed in Document 2 at their installation sites. Summary of the Invention

[0007] The purpose of this invention is to provide a motor that provides centering limit for adjusting the rotor shaft position during the assembly and disassembly of the rotor, stator and end cover.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] An electric motor has a stator core housed in a frame cavity, and end caps are fitted at the stops at both ends of the cavity. The motor is characterized in that a radial web is provided on the hole wall between the end face of the stator core and the stop, and the difference between the distance from the inner end of the radial web to the hole core of the stator core and the radius of the rotor shaft is greater than or equal to the air gap between the rotor and the stator.

[0010] A radial hole is provided on the rotor shaft between the bearing limiting step on the rotor shaft and the end face of the rotor core. At least three radial holes are arranged at intervals around the rotor shaft. Blind holes with the same core as the rotor shaft are provided at both ends of the rotor shaft. The blind holes intersect and communicate with the radial holes. A sliding column is provided in the radial hole. A spring is provided on the rotor shaft. The spring provides elastic force to drive the sliding column to move towards the core side.

[0011] The sliding column moves radially outward to contact the inner end of the radial web, and then moves radially inward to separate from the inner end of the radial web.

[0012] The above solution involves setting a radial web plate inside the frame cavity. The radial web plate is arranged axially between the end face and the stop of the stator core, so it will not interfere with the stator core and end cover in the axial direction. The difference between the distance from the inner end of the radial web plate to the core hole of the stator core and the radius of the rotor shaft is greater than or equal to the air gap between the rotor and the stator. When the radial displacement sliding column set on the rotor shaft extends radially outward, it will be radially blocked by the radial web plate in the circumferential range, thereby adjusting the rotor core to the position that coincides with the core hole of the stator. This solves the problem that the rotor composed of permanent magnet core is difficult to separate from the stator due to strong magnetic attraction. It can also solve the problem that the rotor of a large-size motor with heavy weight is difficult to separate manually when pressed against the stator. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Figure 2 This is a schematic diagram of the structure when the base and rotor are initially assembled;

[0015] Figure 3 , 4 They are Figure 1 , 2 AA section view in the middle;

[0016] Figure 5 , 6 They are Figure 1 , 2 A magnified view of a portion of the image;

[0017] Figure 7 yes Figure 2 A magnified view of a portion of the image;

[0018] Figure 8 , 9 These are schematic diagrams of radial webs with two different structural forms;

[0019] Figure 10 is Figure 9 A schematic diagram of the connection structure between the radial web and the base of the structure shown.

[0020] Figure 11This is a schematic diagram of the rotor shaft structure; Figure 12 yes Figure 11 AA section view in the image. Detailed Implementation

[0021] Combination Figure 1 , 2 As shown, the stator core 3 is placed inside the cavity of the motor frame 1. End caps 2 are installed at the stops 1A and 1B at both ends of the cavity. A radial web 70 is provided on the hole wall of the frame 1 between the end face of the stator core 3 and the stops 1A and 1B. The difference between the distance from the inner end of the radial web 70 to the hole core of the stator core 3 and the radius of the rotor shaft 10 is greater than or equal to the air gap between the rotor and the stator.

[0022] A radial hole 11 is provided on the rotor shaft 10 between the bearing limiting step 13 on the rotor shaft 10 and the end face of the rotor core 20. At least three radial holes 11 are arranged at intervals around the rotor shaft 10. Blind holes 12 with the same core as the rotor shaft 10 are provided at both ends of the rotor shaft 10. The blind holes 12 intersect and communicate with the radial holes 11. A sliding column 30 is provided in the radial hole 11. A spring 40 is provided on the rotor shaft 10. The spring 40 provides elastic force to drive the sliding column 30 to move towards the core side.

[0023] The sliding column 30 is radially displaced outward to contact the inner end of the radial web 70, and then radially displaced inward to separate from the inner end of the radial web 70.

[0024] In the above scheme, combined with Figures 3-6 11, 12, blind holes 12 are used to arrange ejector pins or ejector rods 60. When the ejector pin or ejector rod 60 moves axially inward, it will abut against a sliding column 30 provided in the radial hole 11. The sliding column 30 moves radially along the radial hole 11. The radial web 70, which cooperates with it, is arranged inside the stops 1A, 1B of the mounting end covers 2A, 2B at both ends of the machine base 1. The radial web 70 constitutes the limiting part when the sliding column 30 moves radially outward. The abutting part on the radial web 70 that cooperates with the outer end of the sliding column 30 is located on the same circumference with the center concentric with the stator hole core 3. Therefore, when all the sliding columns 30 move outward along the radial hole 11 at the same time and abut against the radial web 70, such as Figure 4 , 6 As shown, the rotor shaft 10 core must be adjusted to a position concentric with the stator bore core 3. At this point, the assembly of the end cover 2 can be completed without difficulty. See [reference needed]. Figure 1As can be seen, the assembly process of this invention relies solely on the radial hole 11 of the rotor shaft 10 and the sliding column 30 installed within it. The sliding column or slider 30 is driven by a push pin or push rod 60 to engage with the pre-set radial web 70 within the machine base 1, thus achieving a concentric suspension state between the rotor shaft 10 and the stator core 3. At this point, the end cover 2 and the stop portion of the machine base 1 can be aligned and assembled. It should be noted that the radial web 70 is fixed to the machine base 1 after the rotor shaft 10, with the rotor core 20 assembled thereon, is inserted into the stator core 3.

[0025] The radial web 70 includes radially arranged radial plates 71, with 2 to 6 radial plates 71 evenly distributed in the circumferential direction, such as... Figure 3 , 4 As shown in Figures 8 and 9, four radial plates 71 are evenly distributed in the circumferential direction. The inner ends of the radial plates 71 are located on the same circumference, and the center of this circle coincides with the core hole of the stator core 3. Ignoring machining errors, the core hole of the stator core 3 and the core hole of the machine base 1 are concentric.

[0026] See Figure 8 The radial web 70 includes an inner ring plate 72, the inner core of which coincides with the core of the stator core 3. One end of a radial plate 71 is connected to the outer periphery of the inner ring plate 72, and the outer end of the radial plate 71 extends outward and connects to the base 1. Specifically, an outer ring plate 73 is connected to the outer end of the radial plate 71, and the outer edge of the outer ring plate 73 is connected to the base 1. Specifically, radially arranged threaded holes 731 are formed on the outer peripheral surface of the outer ring plate 73, and screws 1D, passing through through holes in the base 1, are connected to the threaded holes 731. Figure 7 As shown.

[0027] like Figure 1 , 2 As shown in Figures 7 and 8, a limiting stop 1C is provided on the inner wall of the hole of the base 1, and the outer edge of the outer ring plate 73 abuts against the limiting stop 1C along the axial direction from the outside to the inside.

[0028] A radial plate 71, constituting the radial web 70, passes through a radial hole in the base 1, with its outer end detachably connected to the base 1, and its inner end extending towards the core of the hole in the base 1. For example... Figure 9 The radial web 70 shown is with Figure 8 The difference shown in the structure is that Figure 8 The inner ring plate 72 and the outer ring plate 73 are provided. Figure 10a , 10b It shows Figure 9The connection scheme between the radial web 70 and the base 1 is shown. To facilitate the connection and disassembly of the radial plate 71 and the base 1, the outer end of the radial plate 71 constituting the radial web 70 is T-shaped. The radial process hole 1E that matches it has a T-shaped stepped cross-section. A threaded hole 1F is provided on the platform of the stepped hole. A corresponding through hole 712 is provided on the flange 711 at the outer end of the radial plate 71. The through hole 712 and the threaded hole 1F are connected by screws. This structure allows the radial plate 71 to be easily placed into the base 1 and easily removed from it. Figure 10a As shown; Figure 10b As shown, the wing plate 711 can be directly connected to the outer wall of the base 1. The connection and disassembly scheme between the radial plate 71 and the base 1 is as follows: the radial process hole 1E is a radial straight hole, and a threaded hole 1F is provided on the side of the radial process hole 1E. The web section of the T-shaped rod-shaped radial plate 71 is inserted into the radial process hole 1E and the wing rod section is located outside the radial process hole 1E. A corresponding light hole 712 is opened on the wing plate 711 at the outer end of the radial plate 71. The light hole 712 and the threaded hole 1F are connected by screws.

[0029] See Figure 11 , 12 The outer section of the blind hole 12 is a threaded hole 121, which is adapted to the external threaded section of the ejector pin 60. The front section of the ejector pin 60 is a tapered rod with a small front cross section and a large rear cross section. The inner end of the sliding column 30 abuts against the tapered surface of the tapered rod section of the ejector pin 60. To ensure that the rotor shaft 10 is initially installed in the hole of the stator 3, the sliding column or slider 30 is required to first retract into the radial hole 11. For the permanent magnet rotor, under the attraction of the permanent magnet force, the rotor shaft 10 is quickly attracted to a certain side hole wall of the stator 3. The axial position of the two in the attracted state has a very small error compared with the axial design position. This axial position error can be corrected when assembling the end cover 2 and the bearing.

[0030] To ensure that the sliding column 30 retracts into the radial hole 11 during initial installation, the present invention provides the following preferred embodiments, see below. Figure 5 , 6 12. The radial hole 11 has an internal thread 111 at its opening. An external threaded ring 50 is fitted onto this internal thread 111. The sliding column 30 is a stepped column with a larger inner diameter and a smaller outer diameter. The smaller diameter section of the sliding column 30 passes through the central through hole of the external threaded ring 50. The inner end of the spring 40, which is fitted onto the smaller diameter section of the sliding column 30, presses against the stepped surface of the sliding column 30, and the outer end of the spring 40 presses against the inner ring surface of the external threaded ring 50. The spring 40, acting as a compression spring, consistently provides elastic force to the sliding column 30, and this elastic force drives the sliding column 30 to move radially inward. Figure 3 , 5 As shown, the outer end of the slide column 30 is flush with the shaft of the rotor shaft 10.

[0031] The solution provided by this invention is not only suitable for assembling motors with rotors made of permanent magnets, but also for assembling ordinary motors. For high-power conventional motors, although there is no assembly problem caused by the magnetic attraction between the stator and the permanent magnet rotor core, the assembly of the end cover is still very difficult due to the large size and heavy weight of the rotor, even with the use of lifting equipment and manual operation. The solution provided by this invention can also easily achieve the assembly of the end cover.

[0032] As a preferred embodiment, the cores of the radial holes 11 are coplanar with the core of the rotor shaft 10. This limits the displacement path of the sliding pins or sliders 30 to a coplanar position, ensuring that all sliding pins or sliders 30 within the circumferential range move synchronously when in contact with the ejector pin or ejector rod 60. To ensure uniform distribution of radial force within the circumferential range during the adjustment of the rotor shaft 10's core, 3 to 4 radial holes 11 are evenly spaced along the circumference of the rotor shaft 10. Figure 3 , 4 As can be seen from 12, radial holes 11 are an example of four evenly distributed holes.

Claims

1. An electric motor, wherein a stator core (3) is placed inside a cavity of a frame (1), and end caps (2) are fitted at the stops (1A, 1B) at both ends of the cavity, characterized in that: A radial web (70) is provided on the hole wall between the end face of the stator core (3) and the stop (1A, 1B). The difference between the distance from the inner end of the radial web (70) to the hole core of the stator core (3) and the radius of the rotor shaft (10) is greater than or equal to the air gap between the rotor and the stator. A radial hole (11) is provided on the rotor shaft (10) between the bearing limiting step (13) on the rotor shaft (10) and the end face of the rotor core (20). At least three radial holes (11) are evenly distributed around the rotor shaft (10). Blind holes (12) with the same core as the rotor shaft (10) are provided at both ends of the rotor shaft (10). The blind holes (12) intersect and communicate with the radial holes (11). A sliding column (30) is provided in the radial hole (11). A spring (40) is provided on the rotor shaft (10). The spring (40) provides elastic force to drive the sliding column (30) to move towards the shaft core. The sliding column (30) moves radially outward to the position of contact with the inner end of the radial web (70). The sliding column (30) moves radially inward to the position of separation from the inner end of the radial web (70). The radial web (70) includes radially arranged radial plates (71), with 2 to 6 radial plates (71) evenly distributed in the circumferential range. The inner ends of the radial plates (71) are located on the same circumference and the center of the circle coincides with the core hole of the stator core (3). The outer section of the blind hole (12) is a threaded hole (121) and the threaded hole (121) is adapted to the external threaded section of the ejector pin (60). The front section of the ejector pin (60) is a tapered rod with a small front section and a large rear section. The inner end of the sliding column (30) abuts against the tapered surface of the tapered rod section of the ejector pin (60).

2. The motor according to claim 1, characterized in that: The radial web (70) includes an inner ring plate (72), the inner core of the inner ring plate (72) coincides with the core of the stator core (3), and one end of the radial plate (71) is connected to the outer periphery of the inner ring plate (72). The outer end of the radial plate (71) extends outward and is connected to the base (1).

3. The motor according to claim 2, characterized in that: The outer end of the radial plate (71) is connected to an outer ring plate (73), and the outer edge of the outer ring plate (73) is connected to the base (1).

4. The motor according to claim 3, characterized in that: A radial threaded hole (731) is provided on the circumferential surface of the outer ring plate (73), and a screw (1D) passing through the through hole on the base (1) is connected to the threaded hole (731).

5. The motor according to claim 3, characterized in that: The inner wall of the hole of the base (1) is provided with a limit stop (1C), and the outer edge of the outer ring plate (73) abuts against the limit stop (1C) from the outside to the inside along the axial direction.

6. The motor according to claim 1, characterized in that: The radial plate (71) constituting the radial web (70) passes through a radial hole in the machine base (1) and the outer end of the radial plate (71) is detachably connected to the machine base (1), while the inner end of the radial plate (71) extends toward the core side of the hole in the machine base (1).

7. The motor according to claim 1, characterized in that: The radial hole (11) has an internal thread (111) at the opening. The internal thread (111) is fitted with an external thread ring (50). The sliding column (30) is a stepped column with a large inner diameter and a small outer diameter. The small diameter section of the sliding column (30) is inserted into the middle through hole of the external thread ring (50). The inner end of the spring (40) fitted on the small diameter section of the sliding column (30) presses against the stepped surface of the sliding column (30), and the outer end of the spring (40) presses against the inner ring surface of the external thread ring (50).

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