CN113141070A

CN113141070A - Rotor punching sheet, rotor and permanent magnet direct drive motor

Info

Publication number: CN113141070A
Application number: CN202010061366.5A
Authority: CN
Inventors: 梅洛明; 鲁方春; 片亨范; 尚健; 石飞虎
Original assignee: Anhui Mingteng Permanent Magnetic Machinery & Electrical Equipment Co ltd; BEIJING MINGCHENG ENVIRONMENTAL PROTECTION TECHNOLOGY CO LTD
Current assignee: Anhui Mingteng Permanent Magnetic Machinery & Electrical Equipment Co ltd; BEIJING MINGCHENG ENVIRONMENTAL PROTECTION TECHNOLOGY CO LTD
Priority date: 2020-01-19
Filing date: 2020-01-19
Publication date: 2021-07-20

Abstract

The embodiment of the invention provides a rotor punching sheet, a rotor and a permanent magnet direct drive motor, wherein the rotor punching sheet comprises a sheet body, the sheet body is provided with an outer periphery, an inner periphery and a first side and a second side, the outer periphery and the inner periphery are opposite, the first side and the second side are connected with one end of the outer periphery and the one end of the inner periphery, which are positioned at the same side, the first side and the second side are symmetrically arranged, the outer periphery is an arc surface, and the length of the outer periphery is greater than that of the inner periphery; so that the sheet body forms a fan shape with four top angles; the four top corners of the sheet body protrude outwards in the fan-shaped circumferential direction to form protruding parts; the sheet body is provided with a first connecting hole and a second connecting hole. The rotor punching sheet provided by the embodiment of the invention is in a sector shape, the rotor is formed by splicing a plurality of sectors (rotor core teeth), magnetic isolation magnetic bridges are not connected among the sectors, the magnetic leakage of the rotor is reduced, and a multi-pole tangential magnetic circuit structure is formed by splicing the plurality of sectors, so that the performance parameters and the power density of the motor can be greatly improved, and the material cost of the motor is reduced.

Description

Rotor punching sheet, rotor and permanent magnet direct drive motor

Technical Field

The 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

At present, direct drive motors are more and more applied in the permanent magnet motor industry, and the scheme that the permanent magnet low-speed direct drive motor replaces a high-speed motor acceleration and deceleration device becomes a great hotspot for the improvement of the motor application industry. Compared with a low-speed motor, the high-speed motor with the same power has small volume and small center height, and is possibly limited by the installation environment when the transformation scheme is designed, so that the volume of the low-speed direct drive motor is required to be as small as possible, and the center height cannot be too high. Therefore, the permanent magnet direct drive motor with high power density becomes the first product of the stage.

Because the rotating speed of the direct-drive motor is low, in order to improve the working frequency of the motor and improve the power density of the motor, the multi-pole design is a conventional scheme of the permanent-magnet direct-drive motor.

For an ultra-low speed permanent magnet direct drive motor, the requirement on the number of poles is more. But after the number of poles becomes many, the table pastes and hardly improves with radial magnetic structure magnet steel quantity, leads to the motor power density to do not high, consequently, adopts radial magnetic structure to promote motor power density and has become preferred scheme.

When a radial magnetic circuit structure is adopted, in order to guarantee the structural strength of a rotor of the motor, the wider magnetism isolating magnetic bridge is required to guarantee the overall structural strength of the rotor punching sheet, but the smaller the width of the magnetism isolating magnetic bridge is, the more saturated the magnetic flux at the magnetic bridge part is, the better the magnetic flux leakage limiting effect is, the wider magnetism isolating magnetic bridge brings the problem of rotor magnetic flux leakage, the using amount of magnetic steel is increased, and the design power density of the motor is reduced.

Disclosure of Invention

In view of the above problems in the prior art, an object of the embodiments of the present invention is to provide a rotor sheet, a rotor, and a permanent magnet direct drive motor, which can omit a magnetic isolation bridge to reduce magnetic leakage and improve motor performance and power density.

The embodiment of the invention provides a rotor punching sheet which comprises a sheet body, wherein the sheet body is provided with an outer peripheral edge, an inner peripheral edge, a first side and a second side, the outer peripheral edge and the inner peripheral edge are opposite, the first side and the second side are connected with one end, located 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 that of the inner peripheral edge; so that the sheet body forms a fan shape with four top angles;

the four top corners of the sheet body protrude outwards in the circumferential direction of the fan shape to form protruding parts;

the sheet body is provided with a first connecting hole and a second connecting hole.

In some embodiments, the first connection hole is a circular hole and the second connection hole is a rectangular hole.

The embodiment of the invention also provides a rotor, which comprises a plurality of rotor core teeth, a fixing ring and a plurality of magnetic steels, wherein each rotor core tooth comprises the plurality of rotor punching sheets which are sequentially laminated, a first connecting hole and a second connecting hole of each rotor punching sheet respectively correspond to each other, a first guide rod penetrates through the first connecting hole, and a second guide rod penetrates through the second connecting hole, so that the plurality of rotor punching sheets which are sequentially laminated are fixedly connected to form the rotor core teeth; the rotor iron core teeth are sequentially arranged around the periphery of the fixing ring at intervals, and a magnetic isolation plate made of a non-magnetic material is arranged between the rotor iron core teeth and the fixing ring; and magnetic steel grooves are formed between two adjacent rotor core teeth, and the magnetic steel is arranged in each magnetic steel groove.

In some embodiments, a first side and a second side of the four corners of the magnetic steel groove, which are positioned at the inner side of the convex part, are respectively provided with a root cleaning groove; the groove wall of the root cleaning groove comprises 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; the two ends of the arc-shaped wall surface are respectively connected with 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 with the protruding portion, and the other end of the tangential wall surface is connected with the first side or the second side.

In some embodiments, the second guide rod is provided with a plurality of threaded holes along the length direction thereof;

each rotor iron core tooth is fixedly arranged on the fixing ring through a plurality of bolts respectively, and the bolts are distributed along the axial direction of the fixing ring and correspond to the threaded holes one by one to be in threaded connection with the corresponding threaded holes.

In some embodiments, the first connection holes and the second connection holes are arranged in a radial direction of the fan shape, and the second connection holes are close to the inner circumferential edge; an opening communicated with the second connecting hole is formed in the inner periphery, so that the bolt is connected with a corresponding threaded hole in the second guide rod in the second connecting hole through the opening; the cross section of the second guide rod is rectangular.

In some embodiments, both ends of the rotor core teeth in the axial direction of the fixing ring are respectively provided with a rotor tooth pressing plate;

the two ends of the first guide rod are respectively provided with external threads, and a gasket which is pressed against the rotor tooth pressing plate is sleeved on the first guide rod and is fastened by a nut which is connected to the first guide rod through threads;

the both ends of second guide arm are equipped with the screw hole to its inside respectively, just the both ends of second guide arm overlap respectively the cover be equipped with the butt in fixed cover on the rotor tooth clamp plate, fixed cover be equipped with the mounting hole that the screw hole link up, wear to establish the screw in screw hole and the mounting hole, so that the second guide arm fastens with fixed cover and rotor tooth clamp plate.

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

In some embodiments, the inner circumferential edge of the rotor sheet is a plane, and the inner ring surface of the rotor core tooth formed by sequentially laminating a plurality of rotor sheets is also a plane; and one surface of the magnetism isolating plate, which is used for being attached to the inner ring surface of the rotor iron core teeth, is also a plane.

The embodiment of the invention also provides a permanent magnet direct drive motor which comprises a stator, a rotating shaft, a front end cover, a rear end cover and the rotor, wherein the rotor is fixed on the rotating shaft and is arranged 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 end and the rear end of the stator and the rotor.

Compared with the prior art, the rotor punching sheet provided by the embodiment of the invention is in a fan shape, the rotor is formed by splicing a plurality of sectors (rotor iron core teeth), no magnetism-isolating magnetic bridge connection exists among the sectors, the magnetic leakage of the rotor is reduced, a multi-pole tangential magnetic circuit structure is formed by splicing the plurality of sectors, the multi-pole tangential magnetic circuit structure is suitable for a multi-pole permanent magnet direct-drive motor, the performance parameters and the power density of the motor can be greatly improved, and the material cost of the motor is reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention.

The summary of various implementations or examples of the technology described in this disclosure is not a comprehensive disclosure of the full scope or all features of the disclosed technology.

Drawings

In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having letter suffixes or different letter suffixes may represent different instances of similar components. The drawings illustrate various embodiments, by way of example and not by way of limitation, and together with the description and claims, serve to explain the inventive embodiments. The same reference numbers will be used throughout the drawings to refer to the same or like parts, where appropriate. Such embodiments are illustrative, and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

Fig. 1 is a schematic structural diagram of a rotor sheet according to an embodiment of the present invention.

Fig. 2 is a partial sectional view of a rotor core tooth of a rotor according to an embodiment of the present invention.

Fig. 3 is an axial side view of a rotor core tooth of a rotor of an embodiment of the present invention.

Fig. 4 is an enlarged view of a portion a in fig. 3.

Fig. 5 is a radial cross-sectional view of a rotor of an embodiment of the present invention.

Fig. 6 is an axial sectional view of a rotor of an embodiment of the present invention.

Reference numerals:

1-tablet body; 2-outer peripheral edge; 3-inner periphery; 4-a first side; 5-a second side; 6-a projection; 7-a first connection hole; 8-a second connection hole; 9-opening; 10-a fixed ring; 11-magnetic steel; 12-a first guide bar; 13-a second guide bar; 14-a magnetic shield; 15-bolt; 16-rotor tooth pressure plate; 17-a gasket; 18-a nut; 19-fixing the sleeve; 20-screws; 21-root cleaning groove; 22-horizontal wall surface; 23-circular arc wall surface; 24-tangential wall surface; 25-rotor spider shaft; 26-rotor core teeth.

Detailed Description

In order to make the objects, 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 drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

To maintain the following description of the embodiments of the present invention clear and concise, a detailed description of known functions and known components of the invention have been omitted.

As shown in fig. 1, an embodiment of the present invention provides a rotor punching sheet, which includes a sheet body 1, where the sheet body 1 has an outer peripheral edge 2 and an inner peripheral edge 3, which are opposite to each other, and a first side 4 and a second side 5, which are connected to one ends of the outer peripheral edge 2 and the inner peripheral edge 3, which are located 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 fan shape with four top angles; four top angles of the sheet body 1 are all protruded outwards in the circumferential direction of the fan shape to form a convex part 6; the sheet body 1 has a first coupling hole 7 and a second coupling hole 8.

Compared with the circular rotor punching sheet in the prior art, the sector rotor punching sheet of the embodiment can form a radial magnetic circuit structure, increases the number of poles, and can improve the power density of a motor; the rotor punching sheets are not in a full circle, and the fan-shaped rotor punching sheets are not connected through magnetic bridges, so that magnetic leakage is reduced.

The laminated sheet body 1 is further fixed through connecting pieces penetrating through the connecting holes after the sheet body 1 is sequentially laminated, the shapes of the first connecting hole 7 and the second connecting hole 8 are not limited, and the first connecting hole 7 and the second connecting hole 8 can be the same or different; and the first connection hole 7 and the second connection hole 8 are arranged in the radial direction of the arc of the outer circumferential edge 2.

Further, as shown in fig. 1, a second connection hole 8 is provided near the inner circumferential edge 3 and communicates with an opening 9 on the inner circumferential edge 3. The function of the openings 9 will be described below.

In some embodiments, the shape of the inner circumferential edge 3 of the rotor sheet is not limited, and it may be a plane, or an arc, and if it is an arc, the bending direction of the arc is consistent with the outer circumferential edge 2. In order to facilitate connection with a magnetic shield 14 to be described later, the inner periphery 3 of the rotor punching sheet is a plane in the embodiment.

As shown in fig. 2 to 6, the 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 magnetic steels 11, each rotor core tooth 26 includes a plurality of rotor sheets stacked in sequence as in the above embodiments, a first connection hole 7 and a second connection hole 8 of the plurality of rotor sheets correspond to each other, a first guide rod 12 penetrates through the first connection hole 7, and a second guide rod 13 penetrates through the second connection hole 8, so as to fixedly connect the plurality of rotor sheets stacked in sequence to form the rotor core teeth 26, and the arrangement of the guide rods can effectively prevent deformation and size deviation of the rotor sheets during stacking; a plurality of rotor core teeth 26 are sequentially arranged at intervals around the periphery of the fixing ring 10, and a magnetic isolation plate 14 of a non-magnetic material is arranged between the rotor core teeth 26 and the fixing ring 10; magnetic steel grooves are formed between two adjacent rotor core teeth 26, and magnetic steel 11 is arranged in each magnetic steel groove.

The rotor of the embodiment of the invention is assembled into a whole circle through the fan-shaped rotor iron core teeth 26, and each rotor iron core tooth 26 respectively forms a magnetic pole, so that the rotor forms a multi-pole tangential magnetic circuit structure; the rotor comprises a plurality of fan-shaped rotor core teeth 26, magnetic steel grooves are formed between the adjacent rotor core teeth 26 respectively, and the number of the magnetic steel grooves is large, so that the using amount of magnetic steel 11 is increased, and the performance and the power density of the motor are improved; and the magnetic steel 11 is arranged between the adjacent rotor core teeth 26, so that a magnetism isolating magnetic bridge is omitted, and the magnetic leakage of the whole rotor is reduced.

In addition, the addition of the non-magnetic-conductive magnetic-isolation plate 14 between the rotor core teeth 26 and the fixed ring 10 can reduce the rotor magnetic flux leakage.

In order to ensure the structural strength of the whole rotor, each rotor core tooth 26 is mounted on the fixing ring 10 by a plurality of bolts 15, and specifically, as shown in fig. 5 and 6, a plurality of threaded holes are formed in the second guide rod 13 along the length direction thereof; the bolts 15 are arranged along the axial direction of the fixing ring 10, sequentially penetrate through the fixing ring 10 and the magnetism isolating plate 14, and are in threaded connection with the threaded holes one by one. Thus, each rotor core tooth 26 is stably fixed with the fixing ring 10 through the plurality of bolts 15, and the structural strength and the structural stability are increased.

With continuing reference to fig. 5 and with reference to fig. 2 and 3, the first connection holes 7 and the second connection holes 8 are arranged in the radial direction of the fan-shaped rotor sheet, and the second connection holes 8 are close to the inner circumferential edge 3; the inner periphery 3 is provided with an opening 9 communicated with the second connecting hole 8, so that a bolt 15 is in threaded connection with a threaded hole on a second guide rod 13 in the second connecting hole 8 through the opening 9; further, in order to facilitate forming a threaded hole in the second guide rod 13, the cross section of the second guide rod 13 of the present embodiment is rectangular. Moreover, the rectangular second guide bar 13 can prevent the rotor sheet from rotating, and further improve the stability of the whole rotor core teeth 26.

In some embodiments, as shown in fig. 2, the rotor core teeth 26 are provided with rotor tooth pressing plates 16 at both ends in the axial direction of the fixed ring 10, respectively; two ends of the first guide rod 12 are respectively provided with external threads, and the first guide rod 12 is sleeved with a gasket 17 which is pressed against the rotor tooth pressing plate 16 and is fastened by a nut 18 which is connected to the first guide rod 12 through threads; threaded holes are respectively formed in the two ends of the second guide rod 13 towards the inner part of the second guide rod, namely, internal threads with certain depth are respectively tapped at the two ends of the second guide rod 13; two end parts of the second guide rod 13 are respectively sleeved with a fixing sleeve 19 abutted to the rotor tooth pressing plate 16, the fixing sleeve 19 is provided with a mounting hole communicated with the threaded hole, and a screw 20 penetrates through the threaded hole and the mounting hole so that the second guide rod 13 is fastened with the fixing sleeve 19 and the rotor tooth pressing plate 16. Rotor tooth pressing plates 16 are respectively arranged at two ends of the rotor core teeth 26, so that the flatness and parallelism of the two ends after the multiple rotor punching sheets are laminated are ensured.

In some embodiments, with continuing reference to fig. 3 and 5, four protrusions 6 of the rotor sheets constituting the same rotor core tooth 26 respectively correspond to the protrusions 6 on the adjacent rotor core teeth 26 to form a notch in which the magnetic steel 11 is embedded; after the plurality of rotor core teeth 26 are sequentially fixed around the fixing ring 10, a magnetic steel groove is formed between every two adjacent rotor core teeth 26, magnetic steel 11 is embedded in the magnetic steel groove, root cleaning grooves 21 are formed in four corners of the magnetic steel groove, and the root cleaning grooves 21 are formed in the first side 4 and the second side 5 of the inner side of the protruding portion 6; the setting of clear root groove 21 can not effectively prevent the interference that leads to because of magnet steel 11 four corners size deviation, can also effectively improve the anti demagnetization ability in magnet steel 11 four corners simultaneously.

Further, as shown in fig. 4, the groove wall of the root cleaning groove 21 includes a horizontal wall surface 22, a circular arc-shaped wall surface 23 and a tangential wall surface 24, and the tangential wall surface 24 is tangent to the circular arc-shaped wall surface 23; the two ends of the circular arc wall surface 23 are respectively connected with 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 with the convex part 6, and the other end of the tangential wall surface 24 is connected with the first side 4 or the second side 5. The back gouging groove 21 of this structure can further improve the anti demagnetization ability of magnet steel 11 four corners.

In order to reduce the cost, the fixing ring 10 can be made of common magnetic conductive materials; the first connecting rod and the second connecting rod are made of magnetic materials; the bolt 15 is made of non-magnetic-conductive stainless steel material so as to prevent the magnetic of the rotor punching sheet from being conducted out; the rotor punching sheet is made of magnetic silicon steel sheets.

For convenience of processing, two surfaces of the magnetic shield 14, which are attached to the rotor core teeth 26 and the fixing ring 10, are both planes, correspondingly, the inner peripheral edge 3 of the rotor sheet is also a plane, and the inner ring surface of the rotor core teeth 26 formed by sequentially laminating a plurality of rotor sheets is also a plane so as to be attached to the magnetic shield 14 tightly; the fixing ring 10 is processed with plane parts corresponding to the magnetic isolation plates 14 respectively to be attached to the magnetic isolation plates 14.

The rotor of the embodiment of the invention is formed by splicing a plurality of sectors (rotor iron core teeth 26), no magnetism-isolating magnetic bridge is connected among the sectors, the leakage flux of the rotor is reduced, a multi-pole tangential magnetic circuit structure is formed by splicing the plurality of sectors, the rotor is suitable for a multi-pole permanent magnet direct-drive motor, the performance parameters and the power density of the motor can be greatly improved, and the material cost of the motor is reduced.

The embodiment of the invention also discloses a permanent magnet direct drive motor, which comprises a shell, a stator, a rotating shaft, a front end cover, a rear end cover and a rotor in any one of the embodiments, wherein the rotor is fixed on the rotating shaft, and the rotating shaft shown in the embodiment is a rotor spoke plate shaft 25; and after the stator punching sheets are laminated, winding and wire embedding insulation processes are carried out, the stator punching sheets are pressed and then pressed into a shell, then the rotor is arranged into the stator, a bearing and front and rear end covers are installed, the front end cover and the rear end cover are respectively arranged on a rotating shaft through the bearing and cover the front end and the rear end of the stator and the rotor, and the complete permanent magnet direct drive motor is assembled.

The above description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more versions thereof) may be used in combination with each other, and it is contemplated that the embodiments may be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. The rotor punching sheet is characterized by comprising a sheet body, wherein the sheet body is provided with an outer peripheral edge, an inner peripheral edge, a first side and a second side, the first side and the second side are connected with one ends of the outer peripheral edge and the inner peripheral edge, the ends of the outer peripheral edge and the inner peripheral edge are positioned 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 that of the inner peripheral edge; so that the sheet body forms a fan shape with four top angles;

2. The rotor sheet as recited in claim 1, wherein the first connection hole is a circular hole, and the second connection hole is a rectangular hole.

3. A rotor is characterized by comprising a plurality of rotor core teeth, a fixing ring and a plurality of magnetic steels, wherein each rotor core tooth comprises a plurality of rotor sheets which are sequentially laminated and are as claimed in claim 1 or 2, a first connecting hole and a second connecting hole of each rotor sheet respectively correspond to each other, a first guide rod penetrates through the first connecting hole, and a second guide rod penetrates through the second connecting hole, so that the plurality of sequentially laminated rotor sheets are fixedly connected to form the rotor core teeth; the rotor iron core teeth are sequentially arranged around the periphery of the fixing ring at intervals, and a magnetic isolation plate made of a non-magnetic material is arranged between the rotor iron core teeth and the fixing ring; and magnetic steel grooves are formed between two adjacent rotor core teeth, and the magnetic steel is arranged in each magnetic steel groove.

4. The rotor as claimed in claim 3, wherein a first side and a second side of the four corners of the magnetic steel slot, which are positioned at the inner side of the convex part, are respectively provided with a root cleaning slot; the groove wall of the root cleaning groove comprises 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; the two ends of the arc-shaped wall surface are respectively connected with 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 with the protruding portion, and the other end of the tangential wall surface is connected with the first side or the second side.

5. The rotor of claim 2, wherein the second guide bar has a plurality of threaded holes along a length thereof;

6. The rotor according to claim 5, wherein the first and second connection holes are arranged in a radial direction of the sector, and the second connection hole is close to the inner circumferential edge; an opening communicated with the second connecting hole is formed in the inner periphery, so that the bolt is connected with a corresponding threaded hole in the second guide rod in the second connecting hole through the opening; the cross section of the second guide rod is rectangular.

7. The rotor according to claim 6, wherein both ends of the rotor core teeth in the axial direction of the fixed ring are respectively provided with a rotor tooth pressing plate;

8. The rotor as claimed in claim 5, wherein the material of the fixing ring is a magnetic conductive material; the first connecting rod and the second connecting rod are made of magnetic materials; the bolt is made of non-magnetic-conductive stainless steel material; the rotor punching sheet is made of magnetic silicon steel sheets.

9. The rotor as claimed in claim 3, wherein the inner circumference of the rotor sheet is a plane, and the inner ring surface of the rotor core teeth formed by sequentially laminating a plurality of the rotor sheets is also a plane; and one surface of the magnetism isolating plate, which is used for being attached to the inner ring surface of the rotor iron core teeth, is also a plane.

10. A permanent-magnet direct-drive motor comprises a stator, a rotating shaft, a front end cover and a rear end cover, and is characterized by further comprising a rotor as claimed in any one of claims 3 to 9, wherein the rotor is fixed on the rotating shaft and is arranged 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 end and the rear end of the stator and the rotor.