Rotor punching sheet, rotor and permanent magnet direct drive motor

Abstract

An embodiment of the present invention provides a rotor punching sheet, a rotor and a permanent magnet direct drive motor. The rotor punching sheet includes a sheet body. The sheet body has opposite outer peripheral edges and inner peripheral edges, and a first side and a second side connected to one end of the outer peripheral edge and the inner peripheral edge on the same side. The first side and the second side are symmetrically arranged. The outer peripheral edge is an arc surface, and the length of the outer peripheral edge is greater than the length of the inner peripheral edge; so that the sheet body forms a sector with four vertex angles. The four vertex angles of the sheet body all protrude outward in the circumferential direction of the sector to form protruding parts; the sheet body has a first connection hole and a second connection hole. The rotor punching sheet provided by the embodiment of the present invention is in a sector shape, and the rotor is formed by splicing multiple sectors (rotor core teeth), and there is no magnetic isolation magnetic bridge connection between the sectors, reducing the rotor leakage magnetic flux. At the same time, a multi-pole and tangential magnetic circuit structure is formed by splicing multiple sectors, which can greatly improve the performance parameters and power density of the motor, and reduce the material cost of the motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet motors, and particularly relates to a rotor punching sheet, a rotor and a permanent magnet direct drive motor. Background Art

[0002] At present, direct drive motors are increasingly used in the permanent magnet motor industry. The solution of replacing the high-speed motor with an acceleration and deceleration device by a permanent magnet low-speed direct drive motor has become a major hot spot in the transformation of the motor application industry. Compared with a high-speed motor of the same power, the high-speed motor has a small volume and a small center height. When designing the transformation solution, it may be restricted by the installation environment, requiring the volume of the low-speed direct drive motor to be as small as possible and the center height not to be too high. Therefore, a permanent magnet direct drive motor with a high power density has become the first choice product at this stage.

[0003] Since the direct drive motor has a low speed, in order to increase the working frequency of the motor and improve the power density of the motor, a multi-pole design is a conventional solution for permanent magnet direct drive motors.

[0004] For an ultra-low speed permanent magnet direct drive motor, more pole numbers are required. However, after the number of poles increases, it is difficult to increase the amount of magnetic steel used in the surface-mounted and radial magnetic circuit structures, resulting in a low power density of the motor. Therefore, adopting a radial magnetic circuit structure to increase the power density of the motor has become the first choice solution.

[0005] When adopting a radial magnetic circuit structure, in order to ensure the structural strength of the rotor of the motor, a relatively wide magnetic isolation bridge is usually required to ensure the overall structural strength of the rotor punching sheet. However, the smaller the width of the magnetic isolation bridge, the more saturated the magnetic flux in the magnetic bridge part, and the better the leakage magnetic effect is restricted. A wider magnetic isolation bridge brings the problem of rotor magnetic leakage, which not only increases the amount of magnetic steel used, but also reduces the designed power density of the motor. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the purpose of the embodiments of the present invention is to provide a rotor punching sheet, a rotor and a permanent magnet direct drive motor that can eliminate the magnetic isolation bridge to reduce magnetic leakage and improve the performance and power density of the motor.

[0007] The embodiments of the present invention provide a rotor punching sheet, which includes a sheet body. The sheet body has opposite outer peripheral edges and inner peripheral edges, and a first side and a second side connected to one end of the outer peripheral edge and the inner peripheral edge on the same side. The first side and the second side are symmetrically arranged. The outer peripheral edge is an arc surface, and the length of the outer peripheral edge is greater than the length of the inner peripheral edge; so that the sheet body forms a sector with four vertex angles;

[0008] All four vertex angles of the sheet body protrude outward in the circumferential direction of the sector to form protruding parts;

[0009] The sheet body is provided with a first connection hole and a second connection hole.

[0010] In some embodiments, the first connection hole is a round hole and the second connection hole is a rectangular hole.

[0011] An embodiment of the present invention also provides a rotor, which includes a plurality of rotor core teeth, a fixing ring, and a plurality of permanent magnets. Each of the rotor core teeth includes a plurality of rotor punching sheets stacked in sequence as described above. The first connection holes and the second connection holes of the plurality of rotor punching sheets respectively correspond to each other. A first guide rod is inserted into the first connection hole, and a second guide rod is inserted into the second connection hole to fixedly connect the plurality of rotor punching sheets stacked in sequence to form the rotor core teeth; the plurality of rotor core teeth are sequentially arranged at intervals around the outer periphery of the fixing ring, and a magnetic isolation plate made of a non-magnetic material is provided between the rotor core teeth and the fixing ring; a permanent magnet groove is formed between two adjacent rotor core teeth, and each permanent magnet groove is respectively provided with the permanent magnet.

[0012] In some embodiments, root clearance grooves are respectively provided on the first side and the second side of the four corners of the permanent magnet groove located inside the protruding portion; the groove wall of the root clearance groove includes a horizontal wall surface, an arc-shaped wall surface, and a tangential wall surface, and the tangential wall surface is tangent to the arc-shaped wall surface; two ends of the arc-shaped wall surface are respectively connected to one end of the horizontal wall surface and one end of the tangential wall surface, the other end of the horizontal wall surface is connected to the protruding portion, and the other end of the tangential wall surface is connected to the first side or the second side.

[0013] In some embodiments, a plurality of threaded holes are provided along the length direction of the second guide rod;

[0014] Each of the rotor core teeth is fixedly installed on the fixing ring through a plurality of bolts. The plurality of bolts are arranged along the axial direction of the fixing ring and correspond to the threaded holes one by one, and are threadedly connected into the corresponding threaded holes.

[0015] In some embodiments, the first connection hole and the second connection hole are arranged in the radial direction of the sector, and the second connection hole is close to the inner peripheral edge; an opening communicating with the second connection hole is provided on the inner peripheral edge, so that the bolt is connected to the corresponding threaded hole on the second guide rod in the second connection hole through the opening; the cross section of the second guide rod is rectangular.

[0016] In some embodiments, rotor tooth pressing plates are respectively provided at both ends of the rotor core teeth in the axial direction of the fixing ring;

[0017] External threads are respectively provided at both ends of the first guide rod. A gasket pressing against the rotor tooth pressing plate is sleeved on the first guide rod and is fastened by a nut threadedly connected to the first guide rod.

[0018] Both ends of the second guide rod are provided with threaded holes towards its interior, and fixing sleeves abutting against the rotor tooth pressing plate are respectively sleeved on both ends of the second guide rod. The fixing sleeves are provided with mounting holes communicating with the threaded holes, and screws are inserted into the threaded holes and the mounting holes to fasten the second guide rod with the fixing sleeves and the rotor tooth pressing plate.

[0019] In some embodiments, the material of the fixing ring is a magnetic conductive material; the materials of the first guide rod and the second guide rod are both magnetic conductive materials; the bolt is made of non-magnetic stainless steel material; the material of the rotor punching sheet is magnetic conductive silicon steel sheet.

[0020] In some embodiments, the inner peripheral edge of the rotor punching sheet is a plane, and the inner ring surface of the rotor core teeth formed by sequentially laminating a plurality of the rotor punching sheets is also a plane; the surface of the magnetic isolation plate for fitting with the inner ring surface of the rotor core teeth is also a plane.

[0021] An embodiment of the present invention further provides a permanent magnet direct drive motor, which includes a stator, a rotating shaft, a front end cover and a rear end cover, and further includes the above-mentioned rotor. The rotor is fixed on the rotating shaft and installed in the stator; the front end cover and the rear end cover are respectively arranged on the rotating shaft through bearings and cover the front and rear ends of the stator and the rotor.

[0022] Compared with the prior art, the rotor punching sheet provided by the embodiment of the present invention is fan-shaped, and the rotor is formed by splicing a plurality of sectors (rotor core teeth), and there is no magnetic isolation bridge connection between the sectors, reducing the rotor magnetic leakage. And a multi-pole and tangential magnetic circuit structure is formed by splicing a plurality of sectors, which is applicable to a multi-pole permanent magnet direct drive motor, can greatly improve the performance parameters and power density of the motor, and at the same time reduce the material cost of the motor.

[0023] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the present invention.

[0024] The overview of various implementations or examples of the technology described in the present invention is not an exhaustive disclosure of the entire scope of the disclosed technology or all features. Brief Description of the Drawings

[0025] In the drawings which are not necessarily drawn to scale, the same reference numerals may describe similar components in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar components. The drawings generally illustrate various embodiments by way of example and not limitation, and are used together with the description and the claims to illustrate the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and not intended as an exhaustive or exclusive embodiment of the apparatus or method.

[0026] Figure 1 This is a schematic structural diagram of the rotor punching sheet according to an embodiment of the present invention.

[0027] Figure 2 This is a partial cross-sectional view of the rotor core teeth of the rotor according to an embodiment of the present invention.

[0028] Figure 3 This is an axial side view of the rotor core teeth of the rotor according to an embodiment of the present invention.

[0029] Figure 4 is Figure 3 an enlarged view of part A in

[0030] Figure 5 This is a radial cross-sectional view of the rotor according to an embodiment of the present invention.

[0031] Figure 6 This is an axial cross-sectional view of the rotor according to an embodiment of the present invention.

[0032] Reference numerals:

[0033] 1 - sheet body; 2 - outer peripheral edge; 3 - inner peripheral edge; 4 - first side; 5 - second side; 6 - protruding portion; 7 - first connecting hole; 8 - second connecting hole; 9 - opening; 10 - fixing ring; 11 - magnet; 12 - first guide rod; 13 - second guide rod; 14 - magnetic separation plate; 15 - bolt; 16 - rotor tooth pressing plate; 17 - gasket; 18 - nut; 19 - fixing sleeve; 20 - screw; 21 - root clearing groove; 22 - horizontal wall surface; 23 - arc-shaped wall surface; 24 - tangential wall surface; 25 - rotor web shaft; 26 - rotor core tooth. Detailed implementation manners

[0034] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0036] To keep the following description of the embodiments of the present invention clear and concise, the detailed descriptions of known functions and known components are omitted in the present invention.

[0037] As Figure 1 shown, an embodiment of the present invention provides a rotor punching sheet, which includes a sheet body 1. The sheet body 1 has opposite outer peripheral edges 2 and inner peripheral edges 3, and a first side 4 and a second side 5 connected to one end of the outer peripheral edge 2 and the inner peripheral edge 3 on the same side. The first side 4 and the second side 5 are symmetrically arranged. The outer peripheral edge 2 is an arc surface, and the length of the outer peripheral edge 2 is greater than the length of the inner peripheral edge 3; so that the sheet body 1 forms a sector with four vertex angles; the four vertex angles of the sheet body 1 all protrude outward in the circumferential direction of the sector to form protruding portions 6; the sheet body 1 has a first connection hole 7 and a second connection hole 8.

[0038] Compared with the circular rotor punching sheet in the prior art, the sector-shaped rotor punching sheet of this embodiment can form a radial magnetic circuit structure, and increases the number of poles, which can improve the power density of the motor; and the rotor punching sheet is not a complete circle, and there is no magnetic bridge connection between the sector-shaped rotor punching sheets, reducing magnetic leakage.

[0039] After the sheet bodies 1 are stacked in sequence, the stacked sheet bodies 1 are further fixed by a connecting member passing through the connection holes. The shapes of the first connection hole 7 and the second connection hole 8 are not limited, and the two may be the same or different. In this embodiment, continuing to combine Figure 1 , the shapes of the first connection hole 7 and the second connection hole 8 are different. Among them, the first connection hole 7 is a circular hole, and the second connection hole 8 is a rectangular hole; and the first connection hole 7 and the second connection hole 8 are arranged in the radial direction of the arc of the outer peripheral edge 2.

[0040] Further, as Figure 1 described, the second connection hole 8 is arranged close to the inner peripheral edge 3 and is communicated with an opening 9 on the inner peripheral edge 3. The function of the opening 9 will be introduced below.

[0041] In some embodiments, the shape of the inner peripheral edge 3 of the rotor punching sheet is not limited. It can be a flat surface or an arc surface. If it is an arc surface, its bending direction is the same as that of the outer peripheral edge 2. For the convenience of connecting with the magnetic isolation plate 14 to be introduced later, the inner peripheral edge 3 of the rotor punching sheet shown in this embodiment is a flat surface.

[0042] As Figures 2 to 6 shown, an embodiment of the present invention also discloses a rotor, which includes a plurality of rotor core teeth 26, a fixing ring 10, and a plurality of permanent magnets 11. Each rotor core tooth 26 includes a plurality of rotor punching sheets as described in the above embodiment stacked in sequence. The first connection holes 7 and the second connection holes 8 of the plurality of rotor punching sheets correspond to each other respectively. A first guide rod 12 is inserted into the first connection hole 7, and a second guide rod 13 is inserted into the second connection hole 8 to fixedly connect the plurality of rotor punching sheets stacked in sequence to form the rotor core tooth 26. The arrangement of the guide rods can effectively prevent deformation and dimensional deviation during the stacking process of the rotor punching sheets; the plurality of rotor core teeth 26 are arranged at intervals in sequence around the outer periphery of the fixing ring 10, and a magnetic isolation plate 14 made of non-magnetic material is provided between the rotor core teeth 26 and the fixing ring 10; a magnetic steel groove is formed between two adjacent rotor core teeth 26, and a permanent magnet 11 is respectively arranged in each magnetic steel groove.

[0043] The rotor of the embodiment of the present invention is assembled into a complete circle by the fan-shaped rotor core teeth 26. Each rotor core tooth 26 forms a magnetic pole respectively, so that the rotor forms a multi-pole and tangential magnetic circuit structure; moreover, since the rotor includes a plurality of fan-shaped rotor core teeth 26, magnetic steel grooves are respectively formed between adjacent rotor core teeth 26, and the number of magnetic steel grooves is large, thereby increasing the amount of permanent magnet 11 used and improving the motor performance and power density; a permanent magnet 11 is arranged between adjacent rotor core teeth 26, eliminating the magnetic isolation bridge and reducing the magnetic leakage of the entire rotor.

[0044] In addition, adding a non-magnetic magnetic isolation plate 14 between the rotor core teeth 26 and the fixing ring 10 can reduce the magnetic leakage of the rotor.

[0045] To ensure the structural strength of the entire rotor, each rotor core tooth 26 is installed on the fixing ring 10 through multiple bolts 15. Specifically, as Figure 5 and Figure 6 shown, a plurality of threaded holes are provided along the length direction of the second guide rod 13; the plurality of bolts 15 are arranged along the axial direction of the fixing ring 10 and respectively pass through the fixing ring 10 and the magnetic isolation plate 14 in sequence and are threadedly connected to the threaded holes one by one. In this way, each rotor core tooth 26 is stably fixed to the fixing ring 10 through multiple bolts 15, increasing the structural strength and structural stability.

[0046] Continuing to combine Figure 5 and cooperating with Figure 2 and Figure 3, the first connection hole 7 and the second connection hole 8 are arranged in the radial direction of the sector-shaped rotor punching sheet, and the second connection hole 8 is close to the inner peripheral edge 3; an opening 9 communicating with the second connection hole 8 is provided on the inner peripheral edge 3, so that a bolt 15 is threadedly connected to a threaded hole on the second guide rod 13 in the second connection hole 8 through the opening 9; further, in order to facilitate the opening of the threaded hole on the second guide rod 13, the cross section of the second guide rod 13 in this embodiment is rectangular. Moreover, the rectangular second guide rod 13 can prevent the rotor punching sheet from rotating, further improving the overall stability of the rotor core teeth 26.

[0047] In some embodiments, as Figure 2 shown, rotor tooth pressing plates 16 are respectively provided at both ends of the rotor core teeth 26 in the axial direction of the fixing ring 10; external threads are respectively provided at both ends of the first guide rod 12, a gasket 17 pressing against the rotor tooth pressing plate 16 is sleeved on the first guide rod 12, and is fastened by a nut 18 threadedly connected to the first guide rod 12; threaded holes are respectively provided towards the inside at both ends of the second guide rod 13, that is, internal threads with a certain depth are respectively tapped at both ends of the second guide rod 13; fixing sleeves 19 abutting against the rotor tooth pressing plate 16 are respectively sleeved on both ends of the second guide rod 13, mounting holes communicating with the threaded holes are provided on the fixing sleeves 19, and screws 20 are inserted into the threaded holes and the mounting holes, so that the second guide rod 13 is fastened to the fixing sleeve 19 and the rotor tooth pressing plate 16. By respectively providing rotor tooth pressing plates 16 at both ends of the rotor core teeth 26, the flatness and parallelism at both ends are ensured after multiple rotor punching sheets are laminated.

[0048] In some embodiments, continue to combine Figure 3 and Figure 5 , the four protruding parts 6 of the rotor punching sheets constituting the same rotor core tooth 26 respectively correspond to cooperate with the protruding parts 6 on the adjacent rotor core teeth 26 to form a notch for embedding the magnet 11; when multiple rotor core teeth 26 are sequentially fixed around the fixing ring 10, a magnet groove is formed between two adjacent rotor core teeth 26, the magnet groove is used for embedding the magnet 11, and root clearance grooves 21 are provided at the four corners of the magnet groove, and the root clearance grooves 21 are provided on the first side 4 and the second side 5 inside the protruding part 6; the setting of the root clearance grooves 21 can not only effectively prevent interference caused by dimensional deviation of the four corners of the magnet 11, but also effectively improve the demagnetization resistance of the four corners of the magnet 11.

[0049] Further, as Figure 4 shown, the groove wall of the root clearance groove 21 includes a horizontal wall surface 22, an arc-shaped wall surface 23 and a tangential wall surface 24, and the tangential wall surface 24 is tangent to the arc-shaped wall surface 23; both ends of the arc-shaped wall surface 23 are respectively connected to one end of the horizontal wall surface 22 and one end of the tangential wall surface 24, the other end of the horizontal wall surface 22 is connected to the protruding part 6, and the other end of the tangential wall surface 24 is connected to the first side 4 or the second side 5. The root clearance groove 21 with this structure can further improve the demagnetization resistance of the four corners of the magnet 11.

[0050] To reduce costs, the fixed ring 10 can be made of ordinary magnetic conductive material; the first guide rod 12 and the second guide rod 13 are both made of magnetic conductive material; the bolt 15 is made of non-magnetic stainless steel material to prevent the magnetic induction of the rotor punching sheet from being exported; the material of the rotor punching sheet is magnetic conductive silicon steel sheet.

[0051] For the convenience of processing, both sides of the magnetic isolation plate 14 that are used to fit with the rotor core teeth 26 and the fixed ring 10 are flat surfaces. Correspondingly, the inner peripheral edge 3 of the rotor punching sheet is also a flat surface, and the inner ring surface of the rotor core teeth 26 formed by sequentially laminating a plurality of rotor punching sheets is also a flat surface, so as to fit tightly with the magnetic isolation plate 14; flat portions are respectively machined at the positions of the fixed ring 10 corresponding to the magnetic isolation plate 14 to fit with the magnetic isolation plate 14.

[0052] The rotor of the embodiment of the present invention is spliced by a plurality of sectors (rotor core teeth 26), and there is no magnetic isolation magnetic bridge connection between the sectors, reducing the rotor magnetic leakage. And a multi-pole, tangential magnetic circuit structure is formed by splicing a plurality of sectors, which is applicable to a multi-pole permanent magnet direct drive motor, can greatly improve the performance parameters and power density of the motor, and at the same time reduce the material cost of the motor.

[0053] The embodiment of the present invention also discloses a permanent magnet direct drive motor, which includes a machine shell, a stator, a rotating shaft, a front end cover and a rear end cover, and further includes the rotor in any one of the above embodiments. The rotor is fixed on the rotating shaft. The rotating shaft shown in this embodiment is the rotor web shaft 25; after the stator punching sheets are laminated, winding and wire embedding insulation processes are carried out. After completion, they are pressed into the machine shell, and then the rotor is installed into the stator, the bearings and the front and rear end covers are installed. The front end cover and the rear end cover are respectively arranged on the rotating shaft through bearings and cover the front and rear ends of the stator and the rotor, and are assembled into a complete permanent magnet direct drive motor.

[0054] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more of their solutions) can be used in combination with each other, and considering these embodiments, they can be combined with each other in various combinations or permutations. The scope of the present invention should be determined with reference to the appended claims and the full scope of the equivalent forms empowered by these claims.

Claims

1. A rotor, characterized in that, It includes a plurality of rotor core teeth, a fixing ring and a plurality of permanent magnets. Each of the rotor core teeth includes a plurality of rotor punching sheets stacked in sequence. The rotor punching sheet includes a sheet body which has opposite outer peripheral edges and inner peripheral edges, and a first side and a second side connected to one end on the same side of the outer peripheral edge and the inner peripheral edge. The first side and the second side are symmetrically arranged. The outer peripheral edge is an arc surface, and the length of the outer peripheral edge is greater than the length of the inner peripheral edge, so that the sheet body forms a sector with four vertex angles. Four vertex angles of the sheet body all protrude outward in the circumferential direction of the sector to form protruding portions. The sheet body has a first connection hole and a second connection hole. The first connection holes and the second connection holes of the plurality of rotor punching sheets correspond to each other respectively. A first guide rod is inserted into the first connection hole, and a second guide rod is inserted into the second connection hole to fixedly connect the plurality of rotor punching sheets stacked in sequence to form the rotor core tooth. The plurality of rotor core teeth are sequentially arranged at intervals around the outer periphery of the fixing ring, and a magnetic isolation plate made of non-magnetic material is arranged between the rotor core tooth and the fixing ring. A permanent magnet groove is formed between two adjacent rotor core teeth, and each permanent magnet groove is respectively provided with the permanent magnet. Root clearing grooves are respectively arranged on the first side and the second side at the four corners of the permanent magnet groove and inside the protruding portion. The groove wall of the root clearing groove includes a horizontal wall surface, an arc-shaped wall surface and a tangential wall surface, and the tangential wall surface is tangent to the arc-shaped wall surface. Two ends of the arc-shaped wall surface are respectively connected to one end of the horizontal wall surface and one end of the tangential wall surface, the other end of the horizontal wall surface is connected to the protruding portion, and the other end of the tangential wall surface is connected to the first side or the second side. The inner peripheral edge of the rotor punching sheet is a plane, and the inner ring surface of the rotor core tooth formed by sequentially stacking the plurality of rotor punching sheets is also a plane. The surface of the magnetic isolation plate for fitting with the inner ring surface of the rotor core tooth is also a plane.

2. The rotor according to claim 1, characterized in that, The first connection hole is a round hole, and the second connection hole is a rectangular hole.

3. The rotor according to claim 1, characterized in that, A plurality of threaded holes are arranged along the length direction of the second guide rod. Each rotor core tooth is respectively fixedly installed on the fixing ring through a plurality of bolts. The plurality of bolts are arranged along the axial direction of the fixing ring and correspond to the threaded holes one by one to be threadedly connected into the corresponding threaded holes.

4. The rotor according to claim 3, characterized in that, The first connection hole and the second connection hole are arranged in the radial direction of the sector, and the second connection hole is close to the inner peripheral edge. An opening communicating with the second connection hole is arranged on the inner peripheral edge, so that the bolt is connected to the corresponding threaded hole on the second guide rod in the second connection hole through the opening. The cross section of the second guide rod is rectangular.

5. The rotor according to claim 4, characterized in that, Rotor tooth pressing plates are respectively arranged at both ends of the rotor core tooth in the axial direction of the fixing ring. External threads are respectively arranged at both ends of the first guide rod. A gasket pressing against the rotor tooth pressing plate is sleeved on the first guide rod and is fastened by a nut threadedly connected to the first guide rod. Both ends of the second guide rod are respectively provided with threaded holes towards its interior, and fixing sleeves abutting against the rotor tooth pressing plate are respectively sleeved on both ends of the second guide rod. An installation hole communicating with the threaded hole is provided on the fixing sleeve, and a screw is inserted through the threaded hole and the installation hole so as to fasten the second guide rod with the fixing sleeve and the rotor tooth pressing plate.

6. The rotor according to claim 3, characterized in that, The material of the fixing ring is a magnetic conductive material; the materials of the first guide rod and the second guide rod are both magnetic conductive materials; the bolt is made of non-magnetic stainless steel material; the material of the rotor punching sheet is magnetic conductive silicon steel sheet.

7. A permanent magnet direct drive motor, comprising a stator, a rotating shaft, a front end cover and a rear end cover, characterized in that, The permanent magnet direct drive motor further includes the rotor according to any one of claims 1 to 6. The rotor is fixed on a rotating shaft and installed in the stator; the front end cover and the rear end cover are respectively arranged on the rotating shaft through bearings and cover the front and rear ends of the stator and the rotor.

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