阅读说明：本技术 一种永磁丝杠传动装置 (Permanent magnet lead screw transmission device ) 是由 杨均悦 葛研军 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种永磁丝杠传动装置,包括永磁丝母总成、永磁丝杠总成、轴承座和导轨；所述的永磁丝母总成包括外轭铁、外永磁体块和外隔离板；所述的永磁丝杠总成包括内转子轭铁、内永磁体块和内隔离板；所述的永磁丝杠总成套装在永磁丝母总成内部,各外永磁体块内表面与各内永磁体块外表面之间存在一层均匀气隙。本发明将现有永磁丝杠的螺旋式结构,简化为由齿形结构与永磁体块的阶梯式分布,可采用铣削、线切割等常用的加工方法实现；丝杠螺距由隔离板长度决定,方便检测,大幅度降低了加工成本。本发明的丝杠与丝母内均安装永磁体块,取代了单侧永磁体式的结构,提高了回路中的磁能积以及气隙中的磁通密度,大幅度增加了丝杠副轴向推力密度。(The invention discloses a permanent magnet lead screw transmission device, which comprises a permanent magnet nut assembly, a permanent magnet lead screw assembly, a bearing seat and a guide rail, wherein the permanent magnet nut assembly is arranged on the bearing seat; the permanent magnet nut assembly comprises an outer yoke iron, an outer permanent magnet block and an outer isolation plate; the permanent magnet screw assembly comprises an inner rotor yoke iron, an inner permanent magnet block and an inner separation plate; the permanent magnet screw assembly is sleeved inside the permanent magnet screw assembly, and a layer of uniform air gap is formed between the inner surface of each outer permanent magnet block and the outer surface of each inner permanent magnet block. The invention simplifies the spiral structure of the existing permanent magnet screw into the step-shaped distribution of a tooth-shaped structure and a permanent magnet block, and can be realized by common processing methods such as milling, linear cutting and the like; the screw pitch of the lead screw is determined by the length of the isolation plate, so that the detection is convenient, and the processing cost is greatly reduced. Permanent magnet blocks are arranged in the screw rod and the screw nut, a single-side permanent magnet structure is replaced, the magnetic energy product in a loop and the magnetic flux density in an air gap are improved, and the axial thrust density of the screw rod on the shaft is greatly increased.)

1. A permanent magnet screw transmission device is characterized in that: comprises a permanent magnet screw nut assembly, a permanent magnet screw assembly, a bearing seat (7) and a guide rail (8); and the bearing seat (7) and the guide rail (8) are fixedly arranged on the foundation.

The permanent magnet screw assembly comprises an outer yoke iron (1), an outer permanent magnet block (2) and an outer isolation plate (3); the center of the outer yoke (1) is a circular through hole, the surface of the through hole is of an axial tooth-shaped groove structure, and the tooth-shaped grooves are uniformly distributed along the circumferential direction of the inner surface of the outer yoke (1); the inner surface of each outer permanent magnet block (2) is an inward concave circumferential arc curved surface, a plurality of outer permanent magnet blocks (2) are arranged in tooth-shaped grooves in the inner surface of the outer yoke iron (1) in an N pole or S pole homodromous mode, and the inner surfaces of the outer permanent magnet blocks (2) form cylindrical surfaces; the adjacent outer permanent magnet blocks (2) in the same tooth-shaped groove are separated by an outer isolation plate (3); the outer permanent magnet blocks (2) in the two adjacent tooth-shaped grooves are staggered in the axial direction at equal intervals, and after the inner surface of the outer yoke iron (1) is unfolded, the outer permanent magnet blocks (2) form equidistant step-shaped distribution; the outer side of the outer yoke (1) is connected with the guide rail (8) in a sliding way and moves linearly along the guide rail (8) in the axial direction;

the permanent magnet screw assembly comprises an inner rotor yoke iron (4), an inner permanent magnet block (5) and an inner separation plate (6); the inner rotor yoke iron (4) is of a cylindrical structure, the outer surface of the inner permanent magnet block (5) is of an axial tooth-shaped groove structure, and the inner permanent magnet block are uniformly distributed along the circumferential direction of the outer surface of the inner rotor yoke iron (4); the outer surface of the inner permanent magnet block (5) is an outer convex circumferential arc curved surface, and is arranged in a tooth-shaped groove on the outer surface of the inner rotor yoke (4) in the direction opposite to the magnetic pole of the outer permanent magnet block; the outer surfaces of the permanent magnet blocks (5) in the blocks form cylindrical surfaces; adjacent inner permanent magnet blocks (5) in the same tooth-shaped groove are separated by an inner separation plate (6), the inner permanent magnet blocks (5) in two adjacent tooth-shaped grooves are staggered in an axial direction at equal intervals, and after the outer surface of the inner rotor yoke iron (4) is unfolded, the inner permanent magnet blocks (5) are distributed in an equidistant step shape; a rotating shaft is arranged in the center of the inner rotor yoke (4), the rotating shaft is supported by a bearing seat (7), and the permanent magnet screw rod assembly rotates along the rotating shaft;

the permanent magnet screw assembly is sleeved in the permanent magnet screw assembly, and a layer of uniform air gap is formed between a cylindrical surface formed on the inner surface of each outer permanent magnet block (2) and a cylindrical surface formed on the outer surface of each inner permanent magnet block (5);

the sum of the areas of the cylindrical surfaces formed on the inner surfaces of all the outer permanent magnet blocks (2) of the outer yoke iron (1) is equal to the sum of the areas of the cylindrical surfaces formed on the outer surfaces of all the inner permanent magnet blocks (5) with the same axial length on the inner rotor yoke iron (4); the same axial length refers to the maximum length of the outer permanent magnet blocks (2) arranged on the outer yoke iron (1).

2. The permanent magnet screw drive according to claim 1, characterized in that: the axial length of the outer permanent magnet block (2) and the axial length of the inner permanent magnet block (5) are equal in a single complete state, and the arc length along the circumferential direction is equal; the axial length of the outer permanent magnet blocks (2) positioned at the boundaries of the two ends of the outer yoke iron (1) and the axial length of the inner permanent magnet blocks (5) positioned at the boundaries of the two ends of the inner rotor yoke iron (4) are not more than the axial length of a single block in a complete state, and the arc length along the circumferential direction is equal;

the axial lengths of the outer isolation plate (3) and the inner isolation plate (6) are equal under the condition that a single block is complete; the axial length of the outer isolation plate (3) positioned at the boundary of the two ends of the outer yoke (1) and the axial length of the inner isolation plate (6) positioned at the boundary of the two ends of the inner rotor yoke (4) are not more than that of a single block in an integral state.

3. The permanent magnet screw drive according to claim 1, characterized in that: the width of the outer permanent magnet block (2) is equal to that of the outer isolation plate (3), and the arc surface of the outer isolation plate (3) and the inner arc surface of the tooth-shaped groove of the outer yoke (1) are on the same circumferential surface; the diameter of the circumference formed by the concave circumferential arc curved surface of the outer permanent magnet block (2) is smaller than the diameter of the inner arc surface of the tooth-shaped groove of the outer yoke iron (1); the widths of the inner permanent magnet block (5) and the inner isolation plate (6) are equal, and the arc surface formed by the inner isolation plate (6) and the outer arc surface of the tooth-shaped groove of the inner rotor yoke iron (4) are on the same circumferential surface; the diameter of the circumference formed by the convex circumferential arc curved surface of the inner permanent magnet block (5) is larger than that of the outer arc surface of the tooth-shaped groove of the inner rotor yoke iron (4).

4. The permanent magnet screw drive according to claim 1, characterized in that: the ratio of the axial length of the single outer isolation plate (3) in the complete state to the axial length of the single outer permanent magnet block (2) in the complete state is less than 1; the axial length ratio of the single inner isolation plate (6) in the complete state to the single inner permanent magnet block (5) in the complete state is less than 1.

5. The permanent magnet screw drive according to claim 1, characterized in that: the number of the tooth-shaped grooves of the outer yoke (1) is equal to that of the inner rotor yoke (4).

6. The permanent magnet screw drive according to claim 1, characterized in that: the axial staggered distance between the outer permanent magnet blocks (2) in the two adjacent tooth-shaped grooves in the permanent magnet screw assembly is equal to the axial staggered distance between the inner permanent magnet blocks (5) in the two adjacent tooth-shaped grooves of the permanent magnet screw assembly.

7. The permanent magnet screw drive according to claim 1, characterized in that: the sum of the axial lengths of the outer permanent magnet blocks (2) in the single complete state and the outer isolation plates (3) in the single complete state is the product of the axial staggered distance between the outer permanent magnet blocks (2) in two adjacent tooth-shaped grooves in the permanent magnet screw assembly and the number of tooth grooves; the sum of the axial lengths of the inner permanent magnet blocks (5) in the single complete state and the inner separating plate (6) in the single complete state is the product of the axial staggered distance of the inner permanent magnet blocks (5) in two adjacent tooth-shaped grooves of the permanent magnet screw assembly and the number of tooth grooves.

8. The permanent magnet screw drive according to claim 1, characterized in that: the outer yoke iron (1) and the inner rotor yoke iron (4) are made of magnetic materials; the outer isolation plate (3) and the inner isolation plate (6) are made of non-magnetic materials.

Technical Field

The invention relates to a transmission device, in particular to a permanent magnet lead screw transmission device.

Background

In the field of traditional mechanical transmission, in order to realize that rotary motion is converted into linear motion, an actuating mechanism such as a mechanical lead screw or a ball screw is mainly adopted, and inevitable defects such as mechanical abrasion, blocking, insufficient overload capacity, noise, vibration and the like can be caused in the operation process of the actuating mechanism. However, the structural form analysis of the existing permanent magnet lead screw still has the following defects:

1. the structure is complex, and in order to realize the structural form of a spiral magnetic field in the process of converting the rotary motion and the linear motion, the permanent magnet is made into a spiral shape, so that the overall structure is complex and the manufacturing cost is high;

2. the axial force is small, in the existing magnetic screw pair structure, one side is a permanent magnet, the other side is a conductor, the screw is driven to move by utilizing the principle of minimum magnetic resistance, and an air gap magnetic field is only provided by the permanent magnet on one side, so that the axial thrust density of the screw pair is limited, and the large-load power operation cannot be realized.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to design a permanent magnet screw transmission device which can simplify the structure and realize high-load power operation.

The invention adopts the following technical scheme:

a permanent magnet lead screw transmission device comprises a permanent magnet nut assembly, a permanent magnet lead screw assembly, a bearing seat and a guide rail; the bearing seat and the guide rail are fixedly arranged on the foundation.

The permanent magnet nut assembly comprises an outer yoke iron, an outer permanent magnet block and an outer isolation plate; the center of the outer yoke is a circular through hole, the surface of the through hole is in an axial tooth-shaped groove structure, and the tooth-shaped grooves are uniformly distributed along the circumferential direction of the inner surface of the outer yoke; the inner surfaces of the outer permanent magnet blocks are concave circumferential arc curved surfaces, the outer permanent magnet blocks are arranged in tooth-shaped grooves in the inner surface of the outer yoke iron in a mode of N poles or S poles in the same direction, and the inner surfaces of the outer permanent magnet blocks form cylindrical surfaces; the adjacent outer permanent magnet blocks in the same tooth-shaped groove are separated by an outer isolation plate; the outer permanent magnet blocks in the two adjacent tooth-shaped grooves are staggered in the axial direction at equal intervals, and after the inner surface of the outer yoke iron is unfolded, the outer permanent magnet blocks form equidistant step-shaped distribution; the outer side of the outer yoke iron is connected with the guide rail in a sliding way and moves linearly along the guide rail in the axial direction;

the permanent magnet screw assembly comprises an inner rotor yoke iron, an inner permanent magnet block and an inner separation plate; the inner rotor yoke iron is of a cylindrical structure, the outer surface of the inner permanent magnet block is of an axial tooth-shaped groove structure, and the inner permanent magnet block are uniformly distributed along the circumferential direction of the outer surface of the inner rotor yoke iron; the outer surface of the inner permanent magnet block is an outer convex circumferential arc curved surface, and the outer permanent magnet block is arranged in a tooth-shaped groove on the outer surface of the inner rotor yoke iron in the direction opposite to the magnetic pole of the outer permanent magnet block; the outer surfaces of the permanent magnet blocks in the blocks form a cylindrical surface; the adjacent inner permanent magnet blocks in the same tooth-shaped groove are separated by an inner separating plate, the inner permanent magnet blocks in the two adjacent tooth-shaped grooves are staggered in an axial direction at equal intervals, and after the outer surface of the inner rotor yoke iron is unfolded, the inner permanent magnet blocks are distributed in an equidistant step shape; a rotating shaft is arranged in the center of the inner rotor yoke iron and supported by a bearing seat, and the permanent magnet screw rod assembly rotates along the rotating shaft;

the permanent magnet screw assembly is sleeved in the permanent magnet screw assembly, and a layer of uniform air gap is formed between a cylindrical surface formed on the inner surface of each outer permanent magnet block and a cylindrical surface formed on the outer surface of each inner permanent magnet block;

the sum of the areas of the cylindrical surfaces formed on the inner surfaces of all the outer permanent magnet blocks of the outer yoke is equal to the sum of the areas of the cylindrical surfaces formed on the outer surfaces of all the inner permanent magnet blocks with the same axial length on the inner rotor yoke; the same axial length refers to the maximum length of the outer permanent magnet blocks arranged on the outer yoke iron.

Furthermore, the axial length of the outer permanent magnet blocks and the axial length of the inner permanent magnet blocks are equal in a single complete state, and the arc length along the circumferential direction is equal; the axial length of the outer permanent magnet blocks positioned on the boundaries of the two ends of the outer yoke iron and the axial length of the inner permanent magnet blocks positioned on the boundaries of the two ends of the inner rotor yoke iron are not more than the axial length of the single block in a complete state, and the arc length along the circumferential direction is equal;

the axial lengths of the outer partition plate and the inner partition plate in a single integral state are equal; the axial length of the outer isolation plate positioned at the boundaries of the two ends of the outer yoke iron and the axial length of the inner isolation plate positioned at the boundaries of the two ends of the inner rotor yoke iron are not more than that of a single block in an integral state.

Furthermore, the width of the outer permanent magnet block is equal to that of the outer isolation plate, and the arc surface of the outer isolation plate and the inner arc surface of the tooth-shaped groove of the outer yoke are on the same circumferential surface; the diameter of the circumference formed by the concave circumferential arc curved surface of the outer permanent magnet block is smaller than the diameter of the inner arc surface of the tooth-shaped groove of the outer yoke iron; the widths of the inner permanent magnet block and the inner isolation plate are equal, and the arc surface formed by the inner isolation plate and the outer arc surface of the tooth-shaped groove of the inner rotor yoke are on the same circumferential surface; the diameter of the circumference formed by the convex circumferential arc curved surface of the inner permanent magnet block is larger than that of the outer arc surface of the tooth-shaped groove of the inner rotor yoke.

Further, the ratio of the axial length of the single outer isolation plate in the complete state to the axial length of the single outer permanent magnet block in the complete state is less than 1; the ratio of the axial length of the single inner isolation plate in the complete state to the axial length of the single inner permanent magnet block in the complete state is less than 1.

Furthermore, the number of the tooth-shaped grooves of the outer yoke iron is equal to that of the tooth-shaped grooves of the inner rotor yoke iron.

Furthermore, the axial staggered distance between the outer permanent magnet blocks in the two adjacent tooth-shaped grooves in the permanent magnet screw assembly is equal to the axial staggered distance between the inner permanent magnet blocks in the two adjacent tooth-shaped grooves of the permanent magnet screw assembly.

Furthermore, the sum of the axial lengths of the outer permanent magnet blocks in the complete state and the outer isolation plate in the complete state is the product of the axial staggered distance between the outer permanent magnet blocks in two adjacent tooth-shaped grooves in the permanent magnet screw assembly and the number of tooth grooves; the sum of the axial lengths of the inner permanent magnet blocks in the complete state and the inner separating plate in the complete state is the product of the axial staggered distance of the inner permanent magnet blocks in two adjacent tooth-shaped grooves of the permanent magnet screw assembly and the number of tooth grooves.

Furthermore, the outer yoke iron and the inner rotor yoke iron are made of magnetic materials; the outer isolation plate and the inner isolation plate are made of non-magnetic materials.

Compared with the existing permanent magnet lead screw, the permanent magnet lead screw has the following obvious substantive characteristics and obvious advantages:

1. the invention has simple manufacturing process, simplifies the spiral structure of the existing permanent magnet screw into the step-shaped distribution of the tooth-shaped structure and the permanent magnet blocks, and can be realized by common processing methods such as milling, linear cutting and the like; the assembly is simplified, the screw pitch of the lead screw is determined by the length of the isolation plate, the detection is convenient, and the processing and manufacturing cost is greatly reduced;

2. in the invention, the permanent magnet blocks are arranged in the screw rod and the screw nut to replace a single-side permanent magnet type structure, thereby improving the magnetic energy product in a loop and the magnetic flux density in an air gap, greatly increasing the axial thrust density of the screw rod and expanding the application range of the screw rod.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a schematic end view of the structure of fig. 1.

Fig. 3 is a schematic structural perspective view of the application of the present invention.

Fig. 4 is a perspective view showing the structure of the outer yoke of the present invention.

Fig. 5 is a perspective view showing the structure of the inner rotor yoke according to the present invention.

Fig. 6 is an expanded view of the permanent magnet nut assembly along the inner surface.

Fig. 7 is an expanded view of the permanent magnet screw assembly along the outer surface.

In the figure, 1, an outer yoke iron, 2, an outer permanent magnet block, 3, an outer isolation plate, 4, an inner rotor yoke iron, 5, an inner permanent magnet block, 6, an inner isolation plate, 7, a bearing seat, 8 and a guide rail.

Detailed Description

The invention will be further described with reference to the accompanying drawings. As shown in fig. 1-7, a permanent magnet screw transmission device includes a permanent magnet screw assembly, a bearing seat 7 and a guide rail 8; and the bearing seat 7 and the guide rail 8 are fixedly arranged on the foundation.

The permanent magnet nut assembly comprises an outer yoke iron 1, an outer permanent magnet block 2 and an outer isolation plate 3; the center of the outer yoke iron 1 is a circular through hole, the surface of the through hole is in an axial tooth-shaped groove structure, and the tooth-shaped grooves are uniformly distributed along the circumferential direction of the inner surface of the outer yoke iron 1; the inner surface of each outer permanent magnet block 2 is an inward concave circumferential arc curved surface, a plurality of outer permanent magnet blocks 2 are arranged in tooth-shaped grooves in the inner surface of the outer yoke iron 1 in a mode of N poles or S poles in the same direction, and the inner surfaces of the plurality of outer permanent magnet blocks 2 form cylindrical surfaces; the adjacent outer permanent magnet blocks 2 in the same tooth-shaped groove are separated by an outer isolation plate 3; the outer permanent magnet blocks 2 in the two adjacent tooth-shaped grooves are staggered in the axial direction at equal intervals, and after the inner surface of the outer yoke iron 1 is unfolded, the outer permanent magnet blocks 2 form equidistant step-shaped distribution; the outer side of the outer yoke iron 1 is connected with the guide rail 8 in a sliding way and moves linearly along the guide rail 8 in the axial direction;

the permanent magnet screw assembly comprises an inner rotor yoke iron 4, an inner permanent magnet block 5 and an inner separation plate 6; the inner rotor yoke iron 4 is of a cylindrical structure, the outer surface of the inner permanent magnet block 5 is of an axial tooth-shaped groove structure, and the inner permanent magnet block is uniformly distributed along the circumferential direction of the outer surface of the inner rotor yoke iron 4; the outer surface of the inner permanent magnet block 5 is an outer convex circumferential arc curved surface, adopts the direction opposite to the magnetic pole of the outer permanent magnet block, and is arranged in a tooth-shaped groove on the outer surface of the inner rotor yoke iron 4; the outer surfaces of the permanent magnet blocks 5 in the blocks form cylindrical surfaces; adjacent inner permanent magnet blocks 5 in the same tooth-shaped groove are separated by an inner separation plate 6, the inner permanent magnet blocks 5 in two adjacent tooth-shaped grooves are staggered in an axial direction at equal intervals, and after the outer surface of the inner rotor yoke iron 4 is unfolded, the inner permanent magnet blocks 5 are distributed in an equidistant step shape; a rotating shaft is arranged in the center of the inner rotor yoke iron 4, the rotating shaft is supported by a bearing seat 7, and the permanent magnet screw rod assembly rotates along the rotating shaft;

the permanent magnet screw assembly is sleeved in the permanent magnet screw assembly, and a uniform air gap is formed between a cylindrical surface formed on the inner surface of each outer permanent magnet block 2 and a cylindrical surface formed on the outer surface of each inner permanent magnet block 5;

the sum of the areas of the cylindrical surfaces formed on the inner surfaces of all the outer permanent magnet blocks 2 of the outer yoke iron 1 is equal to the sum of the areas of the cylindrical surfaces formed on the outer surfaces of all the inner permanent magnet blocks 5 with the same axial length on the inner rotor yoke iron 4; the same axial length refers to the maximum length of the outer permanent magnet blocks 2 mounted on the outer yoke iron 1.

Further, the axial length of the outer permanent magnet blocks 2 and the axial length of the inner permanent magnet blocks 5 are equal in a single complete state, and the arc length along the circumferential direction is equal; the axial length of the outer permanent magnet blocks 2 positioned at the boundaries of the two ends of the outer yoke iron 1 and the axial length of the inner permanent magnet blocks 5 positioned at the boundaries of the two ends of the inner rotor yoke iron 4 are not more than the axial length of a single block in a complete state, and the arc length along the circumferential direction is equal;

the axial length of the outer isolation plate 3 and the axial length of the inner isolation plate 6 are equal under the integral state of a single block; the axial length of the outer isolation plate 3 positioned at the boundary of the two ends of the outer yoke iron 1 and the axial length of the inner isolation plate 6 positioned at the boundary of the two ends of the inner rotor yoke iron 4 are not more than the axial length of the monolithic block in the complete state.

Furthermore, the width of the outer permanent magnet block 2 is equal to that of the outer isolation plate 3, and the arc surface of the outer isolation plate 3 and the inner arc surface of the tooth-shaped groove of the outer yoke 1 are on the same circumferential surface; the diameter of the circumference formed by the concave circumferential arc curved surface of the outer permanent magnet block 2 is smaller than the diameter of the inner arc surface of the tooth-shaped groove of the outer yoke iron 1; the widths of the inner permanent magnet block 5 and the inner isolation plate 6 are equal, and the arc surface formed by the inner isolation plate 6 and the outer arc surface of the tooth-shaped groove of the inner rotor yoke iron 4 are on the same circumferential surface; the diameter of the circumference formed by the convex circumferential arc curved surface of the inner permanent magnet block 5 is larger than that of the outer arc surface of the tooth-shaped groove of the inner rotor yoke iron 4.

Further, the ratio of the axial length of the single outer isolation plate 3 in the complete state to the axial length of the single outer permanent magnet block 2 in the complete state is less than 1; the ratio of the axial length of the single inner isolation plate 6 in the complete state to the axial length of the single inner permanent magnet block 5 in the complete state is less than 1.

Furthermore, the number of the tooth-shaped grooves of the outer yoke iron 1 is equal to the number of the tooth-shaped grooves of the inner rotor yoke iron 4.

Further, the axial staggered distance between the outer permanent magnet blocks 2 in the two adjacent tooth-shaped grooves in the permanent magnet screw assembly is equal to the axial staggered distance between the inner permanent magnet blocks 5 in the two adjacent tooth-shaped grooves of the permanent magnet screw assembly.

Further, the sum of the axial lengths of the outer permanent magnet blocks 2 in the single complete state and the outer isolation plates 3 in the single complete state is the product of the axial staggered distance between the outer permanent magnet blocks 2 in the two adjacent tooth-shaped grooves in the permanent magnet nut assembly and the number of tooth grooves; the sum of the axial lengths of the inner permanent magnet blocks 5 in the single complete state and the inner separating plates 6 in the single complete state is the product of the axial staggered distance of the inner permanent magnet blocks 5 in the two adjacent tooth-shaped grooves of the permanent magnet screw assembly and the number of tooth grooves.

Further, the outer yoke iron 1 and the inner rotor yoke iron 4 are made of magnetic materials; the outer isolation plate 3 and the inner isolation plate 6 are made of non-magnetic materials.

The working principle of the invention is as follows:

according to the invention, the outer permanent magnet blocks 2 in the outer yoke iron 1 are distributed in a step shape along the tooth-shaped grooves, and the thread structure of a screw nut in a mechanical screw rod pair is simulated; the inner permanent magnet blocks 5 in the inner rotor yoke iron 4 are also distributed in a step shape along the tooth-shaped grooves, and the thread structure of a screw rod in the mechanical screw rod pair is simulated; the permanent magnet screw assembly can move linearly along the guide rail 8 in the axial direction, and the permanent magnet screw assembly is fixed by the bearing seat 7 and can rotate completely along the center of the permanent magnet screw assembly. A uniform air gap is kept between the permanent magnet screw nut assembly and the permanent magnet screw assembly.

After the assembly is finished, the permanent magnet blocks on the two sides of the air gap have opposite magnetic poles, and a fixed relative balance position is kept under the action of magnetic field attraction according to the minimum magnetic resistance principle to form a stable magnetic field loop of the inner permanent magnet block and the outer permanent magnet block; when the permanent magnet screw assembly rotates under the action of driving torque, a magnetic field loop at an initial position is damaged, the permanent magnet screw assembly moves under the action of magnetic field force, and the permanent magnet screw assembly can only linearly move to a new magnetic resistance minimum balance position along the axial direction due to the limitation of the guide rail 8, so that the rotary motion of the permanent magnet screw assembly is converted into the linear motion of the permanent magnet screw assembly by utilizing a magnetic field.

Because the permanent magnet lead screw assembly and the permanent magnet blocks in the permanent magnet lead screw assembly are correspondingly arranged, the same transmission form as that of a mechanical lead screw can be realized, and the screw pitch is equal to the axial length of the permanent magnet blocks plus the axial length of the isolation plate.

The present invention is not limited to the embodiment, and any equivalent idea or change within the technical scope of the present invention is to be regarded as the protection scope of the present invention.