Motor rotors and permanent magnet motors

Abstract

The present application provides a motor rotor and a permanent magnet motor. The motor rotor comprises a rotating shaft, a fixing plate (1) and a carbon fiber sheath (2), wherein the rotating shaft comprises a first shaft (3), a permanent magnet (4) and a second shaft (5) arranged in sequence along the axial direction, the fixing plate (1) extends in the axial direction of the rotating shaft, the first end of the fixing plate (1) is fixedly connected to the first shaft (3), the second end of the fixing plate (1) is fixedly connected to the second shaft (5), there are at least two fixing plates (1), at least two fixing plates (1) are arranged in sequence along the circumferential direction on the outer peripheral side of the rotating shaft and spliced ​​into a cylinder, and the carbon fiber sheath (2) is wound on the outer peripheral side of the cylinder. According to the motor rotor of the present application, the carbon fiber sheath can be effectively prevented from breaking, and the structural safety of the permanent magnet when the motor rotor rotates at high speed can be ensured.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and in particular to a motor rotor and a permanent magnet motor. Background Art

[0002] As the country vigorously promotes industrial upgrading, the motor field will continue to develop towards high speed and miniaturization. The surface-mounted rotor has a simple structure and is easy to assemble, so it is often used in the field of high-speed motors. Due to the low tensile strength of permanent magnets, a sheath is usually added to the outer surface of the permanent magnet. The sheath material is often made of high-strength alloy or carbon fiber.

[0003] As the motor power and speed gradually increase, the outer diameter of the permanent magnet of the surface-mounted motor rotor will increase accordingly, and the centrifugal force on the rotor will also increase accordingly; the yield strength of the high-strength alloy sheath also has a limit and cannot guarantee the safety of the rotor structure at higher speeds; the radial and axial strength of the carbon fiber sheath is very low and cannot meet the rotor stiffness requirements. The rotor is easy to bend during operation, and the carbon fiber sheath will axially break at the contact position of the multi-segment permanent magnet and the contact position of the permanent magnet and the shaft; in addition, the initial winding tension provided by the existing carbon fiber winding technology is limited, and the compressive stress provided by the carbon fiber sheath to the wrapped object is limited. If the compressive stress of the carbon fiber sheath does not directly act on the permanent magnet, it is difficult to protect the permanent magnet at high speeds. Therefore, it is difficult to ensure the structural safety of the permanent magnet when rotating at high speed using a double sheath of carbon fiber and high-strength alloy. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a motor rotor and a permanent magnet motor, which can effectively avoid the breakage of the carbon fiber sheath and ensure the structural safety of the permanent magnet when the motor rotor rotates at high speed.

[0005] In order to solve the above problems, the present application provides a motor rotor, including a rotating shaft, a fixed plate and a carbon fiber sheath, the rotating shaft including a first shaft, a permanent magnet and a second shaft arranged in sequence along the axial direction, the fixed plate extends along the axial direction of the rotating shaft, the first end of the fixed plate is fixedly connected to the first shaft, the second end of the fixed plate is fixedly connected to the second shaft, there are at least two fixed plates, at least two fixed plates are arranged in sequence along the circumferential direction on the outer circumferential side of the rotating shaft and spliced ​​into a cylinder, and the carbon fiber sheath is wrapped around the outer circumferential side of the cylinder.

[0006] Preferably, the first shaft and the second shaft both include a shaft extension end and a main shaft end, the shaft extension end and the main shaft end form a step structure, the permanent magnet is located between the main shaft end of the first shaft and the main shaft end of the second shaft, the first end of the fixed plate is fixedly connected to the main shaft end of the first shaft, and the second end of the fixed plate is fixedly connected to the main shaft end of the second shaft.

[0007] Preferably, the fixed plate includes a plate body and end plates arranged at both ends of the plate body, the plate body is sleeved outside the rotating shaft, a first pin hole is arranged on the end plate of the fixed plate, and a second pin hole is arranged on the end surface of the main shaft end, and the fixed plate and the first shaft, and the fixed plate and the second shaft are fixedly connected by pins arranged in the first pin hole and the second pin hole respectively.

[0008] Preferably, the end surface of the pin is lower than the end surface of the main shaft end close to the shaft extension end, or the end surface of the pin is flush with the end surface of the main shaft end.

[0009] Preferably, the end plate has an inner circular surface that matches the shaft extension end, and the diameter of the inner circular surface of the end plate is larger than the diameter of the shaft extension end; and / or the plate body has an inner arc surface that matches the outer circumferential surface of the rotating shaft, and the inner arc surface fits the outer circumferential surface of the rotating shaft.

[0010] Preferably, a rotor baffle is sleeved on the shaft extension end, and the rotor baffle is stopped outside the main shaft end.

[0011] Preferably, there is an interference fit between the rotor baffle and the shaft extension end.

[0012] Preferably, a nut is further provided outside the rotor baffle, and the nut is threadedly connected to the shaft extension end, so that the nut forms an axial limit for the rotor baffle.

[0013] Preferably, the carbon fiber sheath and the cylinder are interference fit.

[0014] Preferably, the outer peripheral surface of the cylinder is a smooth surface.

[0015] Preferably, the first shaft and the second shaft are made of non-magnetic conductive material.

[0016] According to another aspect of the present application, a permanent magnet motor is provided, comprising a motor rotor, which is the motor rotor described above.

[0017] The motor rotor provided in the present application includes a rotating shaft, a fixed plate and a carbon fiber sheath. The rotating shaft includes a first shaft, a permanent magnet and a second shaft arranged in sequence along the axial direction. The fixed plate extends along the axial direction of the rotating shaft. The first end of the fixed plate is fixedly connected to the first shaft, and the second end of the fixed plate is fixedly connected to the second shaft. There are at least two fixed plates, and at least two fixed plates are arranged in sequence along the circumferential direction on the outer circumferential side of the rotating shaft and spliced ​​into a cylinder. The carbon fiber sheath is wrapped around the outer circumferential side of the cylinder. The motor rotor is provided with a split fixing plate outside the rotating shaft formed by the first shaft, the permanent magnet and the second shaft. The two ends of the fixing plate are fixedly connected to the first shaft and the second shaft. The fixing plate can be used to provide the radial and axial strength required for the permanent magnet and the cooperation between the permanent magnet and the shaft, so as to avoid the carbon fiber sheath being subjected to large radial and axial effects during the movement of the motor rotor. At the same time, the carbon fiber sheath can be used to provide large circumferential strength for the permanent magnet. Through the cooperation of the fixing plate and the carbon fiber sheath, the bending resistance of the entire shaft of the motor rotor can be effectively improved, so that the carbon fiber sheath can directly apply compressive stress to the first shaft, the second shaft and the permanent magnet through the split fixing plate, thereby protecting the structural safety of the permanent magnet when the motor rotor rotates at high speed, preventing the carbon fiber sheath from axial fracture during operation, further improving the limiting speed of the motor, and improving the power density of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic cross-sectional view of a motor rotor according to an embodiment of the present application;

[0019] Figure 2 A schematic diagram of the exploded structure of a motor rotor according to an embodiment of the present application;

[0020] Figure 3 A three-dimensional structural diagram of a first axis of a motor rotor according to an embodiment of the present application;

[0021] Figure 4 A three-dimensional structural diagram of a fixing plate of a motor rotor according to an embodiment of the present application;

[0022] Figure 5 This is a force analysis diagram of the motor rotor according to an embodiment of the present application.

[0023] The reference numerals are:

[0024] 1. Fixing plate; 2. Carbon fiber sheath; 3. First shaft; 4. Permanent magnet; 5. Second shaft; 6. Shaft extension end; 7. Spindle end; 8. Plate body; 9. End plate; 10. First pin hole; 11. Second pin hole; 12. Pin; 13. Rotor baffle; 14. Nut. DETAILED DESCRIPTION

[0025] See also Figures 1 to 5As shown, according to an embodiment of the present application, the motor rotor includes a rotating shaft, a fixed plate 1 and a carbon fiber sheath 2, the rotating shaft includes a first shaft 3, a permanent magnet 4 and a second shaft 5 arranged in sequence along the axial direction, the fixed plate 1 extends along the axial direction of the rotating shaft, the first end of the fixed plate 1 is fixedly connected to the first shaft 3, the second end of the fixed plate 1 is fixedly connected to the second shaft 5, there are at least two fixed plates 1, at least two fixed plates 1 are arranged in sequence along the circumferential direction on the outer circumferential side of the rotating shaft and spliced ​​into a cylinder, and the carbon fiber sheath 2 is wrapped around the outer circumferential side of the cylinder.

[0026] The motor rotor is provided with a split fixing plate 1 on the outer sleeve of the rotating shaft formed by the first shaft 3, the permanent magnet 4 and the second shaft 5. The two ends of the fixing plate 1 are fixedly connected to the first shaft 3 and the second shaft 5. The fixing plate 1 can be used to provide the radial and axial strength required for the permanent magnet 4 and the cooperation between the permanent magnet 4 and the shaft, so as to avoid the carbon fiber sheath 2 from being subjected to large radial and axial effects during the movement of the motor rotor. At the same time, the carbon fiber sheath 2 can be used to provide a large circumferential strength for the permanent magnet 4. Through the cooperation of the fixing plate 1 and the carbon fiber sheath 2, the bending resistance of the entire shaft of the motor rotor can be effectively improved, so that the carbon fiber sheath 2 can directly apply compressive stress to the first shaft 3, the second shaft 5 and the permanent magnet 4 through the split fixing plate 1, thereby protecting the structural safety of the permanent magnet 4 when the motor rotor rotates at high speed, preventing the carbon fiber sheath 2 from axial fracture during operation, further improving the limiting speed of the motor, and improving the power density of the motor.

[0027] The first shaft 3 and the second shaft 5 both include an extension end 6 and a main shaft end 7, the extension end 6 and the main shaft end 7 form a step structure, the permanent magnet 4 is located between the main shaft end 7 of the first shaft 3 and the main shaft end 7 of the second shaft 5, the first end of the fixed plate 1 is fixedly connected to the main shaft end 7 of the first shaft 3, and the second end of the fixed plate 1 is fixedly connected to the main shaft end 7 of the second shaft 5.

[0028] The first end of the fixing plate 1 is fixedly connected to the first shaft 3, and the second end is fixedly connected to the second shaft 5. Therefore, the fixed connection between the first shaft 3 and the second shaft 5 can be achieved through the fixing plate 1. At the same time, since the permanent magnet 4 is located between the first shaft 3 and the second shaft 5, the permanent magnet 4 can also be axially and radially limited by the fixing plate 1. The fixing plate 1 is used to eliminate the axial and radial effects of the permanent magnet 4 on the carbon fiber sheath 2 during the operation of the motor rotor, thereby avoiding the axial fracture of the carbon fiber sheath 2 at the contact position between the permanent magnet 4 and the first shaft 3 or the second shaft 5 during the operation of the motor rotor.

[0029] The fixed plate 1 includes a plate body 8 and end plates 9 arranged at both ends of the plate body 8. The plate body 8 is sleeved outside the rotating shaft. A first pin hole 10 is arranged on the end plate 9 of the fixed plate 1, and a second pin hole 11 is arranged on the end surface of the main shaft end 7. The fixed plate 1 and the first shaft 3, and the fixed plate 1 and the second shaft 5 are fixedly connected by pins 12 arranged in the first pin hole 10 and the second pin hole 11 respectively.

[0030] The fixing plate 1 is made of non-magnetic material, specifically stainless steel or non-magnetic alloy. The fixing plate 1 is fixedly connected with the first shaft 3 and the second shaft 5 through the end plates 9 at both ends, so the axial position limiting of the fixing plate 1 between the first shaft 3, the permanent magnet 4 and the second shaft 5 can be achieved through the end plates 9 at both ends, and the fixing plate 1 can be fixedly connected with the first shaft 3, the permanent magnet 4 and the second shaft 5 in the radial and circumferential directions through the pins 12.

[0031] First pin holes 10 are respectively provided on both sides of the fixing plate 1, and second pin holes 11 are provided on the spindle ends 7 of the first shaft 3 and the second shaft 5. Each spindle end 7 is provided with N (N≥2) second pin holes 11. The number of fixing plates 1 is also N, and one end of each fixing plate 1 is provided with one first pin hole 10, so that a fixed connection between each fixing plate 1 and the spindle end 7 can be achieved. N fixing plates 1 can be spliced ​​into a complete cylinder to achieve installation cooperation with the rotating shaft.

[0032] The end plate 9 has an inner circular surface that matches the shaft extension end 6 . The inner circular surface diameter of the end plate 9 is larger than the diameter of the shaft extension end 6 , so that the inner circular surface of the end plate 9 can fully match the outer circumferential surface of the shaft extension end 6 .

[0033] The plate body 8 has an inner arc surface that matches the outer circumference of the rotating shaft. The inner arc surface fits the outer circumference of the rotating shaft, which can ensure full contact between the fixed plate 1 and the first shaft 3, the permanent magnet 4 and the second shaft 5, thereby ensuring the structural integrity and consistency of the motor rotor.

[0034] A root cleaning process is performed at the inner top corner of the fixing plate 1 to avoid interference between the fixing plate 1 and the first shaft 3 or the second shaft 5 at the inner top corner, to ensure that the fixing plate 1 and the first shaft 3 and the second shaft 5 are fully matched, so that the inner side surfaces of the two end plates 9 of the fixing plate 1 can be tightly attached to the end surfaces of the main shaft ends 7 of the first shaft 3 and the second shaft 5, so that the first shaft 3 and the second shaft 5 can be pressed and fitted with the permanent magnet 4, and the fixing plate 1 can play an effective connecting and fixing role.

[0035] In one embodiment, the end face of the pin 12 is lower than the end face of the main shaft end 7 close to the shaft extension end 6, or the end face of the pin 12 is flush with the end face of the main shaft end 7, so that the pin 12 can effectively connect the rotating shaft and the fixed plate 1, while avoiding the use of the pin 12 from interfering with the overall assembly of the motor rotor.

[0036] The first shaft 3 and the second shaft 5 are both supported by non-magnetic conductive materials such as stainless steel or non-magnetic conductive alloy, so as to effectively reduce the axial magnetic leakage of the permanent magnet 4 .

[0037] A rotor baffle 13 is sleeved on the shaft extension end 6, and the rotor baffle 13 is stopped outside the main shaft end 7, which can form an axial limit for the pin 12 to prevent the pin 12 from escaping from the first pin hole 10 of the fixing plate 1, thereby improving the stability and reliability of the overall structure of the motor rotor.

[0038] In one embodiment, the interference fit between the rotor baffle 13 and the shaft extension end 6 can effectively ensure the stability of the matching structure between the rotor baffle 13 and the shaft extension end 6.

[0039] A nut 14 is also provided outside the rotor baffle 13, and the nut 14 is threadedly connected to the shaft extension end 6, and the nut 14 forms an axial limit for the rotor baffle 13, so that the rotor baffle 13 is kept in a locked position to prevent the rotor baffle 13 from axial displacement. An external thread can be provided on the shaft extension end 6, and the external thread of the shaft extension end 6 cooperates with the nut 14 to achieve locking and fixing of the nut 14 on the first shaft 3 or the second shaft 5.

[0040] The interference fit between the carbon fiber sheath 2 and the cylinder can ensure that the compressive stress of the carbon fiber sheath 2 can be fully transmitted to the fixing plate 1.

[0041] The outer peripheral surface of the cylinder is a smooth surface, which can avoid the problem of axial fracture of the carbon fiber sheath 2 caused by friction on the carbon fiber sheath 2 during the operation of the motor rotor.

[0042] The first shaft 3 and the second shaft 5 are made of non-magnetic conductive materials.

[0043] The assembly process of the motor rotor is as follows: after the first shaft 3, the permanent magnet 4 and the second shaft 5 are spliced, the fixing plate 1 is installed, and the fixing plate 1 is locked into an integral structure with the first shaft 3 and the second shaft 5 by the pin 12; the heating temperature of the rotor baffle 13 is calculated according to the interference amount, and the rotor baffle 13 is respectively assembled on the first shaft 3 and the second shaft 5, so that the rotor baffle 13 and the first shaft 3 and the second shaft 5 have an interference fit, and then the nut 14 is assembled, and the inner end faces of both sides of the fixing plate 1 are locked to the end faces of the main shaft ends 7 of the first shaft 3 and the second shaft 5 by the nut 14, so that the whole motor rotor has the ability to resist bending, and the radial force (i.e., compressive stress) between the fixing plate 1 and the first shaft 3, the permanent magnet 4 and the second shaft 5 is very small. Finally, the carbon fiber is wound circumferentially on the outer surface of the fixing plate 1, and the tension of the carbon fiber must be ensured to be consistent during the entire winding process. After the winding is completed, the whole motor rotor is baked at a certain temperature to shape the carbon fiber sheath 2, and the whole motor rotor is completed after natural cooling.

[0044] See also Figure 5 As shown, due to the use of a segmented fixed plate structure, the compressive stress of the carbon fiber sheath 2 on the fixed plate 1 can directly act on the first shaft 3, the permanent magnet 4 and the second shaft 5 through the force transfer effect. According to the principle of force interaction, the centrifugal force exerted on the permanent magnet 4 when the rotor rotates at high speed will also directly act on the carbon fiber sheath 2. Therefore, when the motor rotor rotates, the actual centrifugal force exerted on the permanent magnet 4 is F2-F1, where F1 is the centrifugal force exerted on the motor rotor when the motor rotor rotates, and F2 is the pressure of the carbon fiber sheath 2 on the permanent magnet when it is static.

[0045] The circumferential strength of the carbon fiber sheath 2 is ≥1800MPa (much higher than the current high-strength alloy sheath), so it can effectively protect the structural safety of the fixed plate 1 and the permanent magnet 4; because the carbon fiber is wound on the smooth outer surface of the fixed plate 1, it will not be subject to additional friction or cutting, so the axial fracture problem of the carbon fiber sheath 2 can also be effectively solved.

[0046] According to an embodiment of the present application, the permanent magnet motor includes a motor rotor, which is the motor rotor mentioned above.

[0047] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0048] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A motor rotor, characterized in that: The invention comprises a rotating shaft, a fixing plate (1) and a carbon fiber sheath (2), wherein the rotating shaft comprises a first shaft (3), a permanent magnet (4) and a second shaft (5) which are sequentially arranged along the axial direction, the fixing plate (1) extends along the axial direction of the rotating shaft, a first end of the fixing plate (1) is fixedly connected to the first shaft (3), and a second end of the fixing plate (1) is fixedly connected to the second shaft (5), there are at least two fixing plates (1), and at least two fixing plates (1) are sequentially arranged along the circumferential direction on the outer circumference of the rotating shaft and spliced ​​into a cylinder, and the carbon fiber sheath (2) is wound around the outer circumference of the cylinder; The first shaft (3) and the second shaft (5) both comprise a shaft extension end (6) and a main shaft end (7), the shaft extension end (6) and the main shaft end (7) forming a step structure, the permanent magnet (4) being located between the main shaft end (7) of the first shaft (3) and the main shaft end (7) of the second shaft (5), the first end of the fixing plate (1) being fixedly connected to the main shaft end (7) of the first shaft (3), and the second end of the fixing plate (1) being fixedly connected to the main shaft end (7) of the second shaft (5); The fixing plate (1) comprises a plate body (8) and end plates (9) arranged at both ends of the plate body (8); the plate body (8) is sleeved outside the rotating shaft; a first pin hole (10) is arranged on the end plate (9) of the fixing plate (1); a second pin hole (11) is arranged on the end surface of the main shaft end (7) away from the permanent magnet (4); the fixing plate (1) and the first shaft (3) are fixedly connected, and the fixing plate (1) and the second shaft (5) are fixedly connected via pins (12) arranged in the first pin hole (10) and the second pin hole (11), respectively; The end face of the pin (12) is lower than the end face of the main shaft end (7) close to the shaft extension end (6), and a rotor baffle (13) is sleeved on the shaft extension end (6), and the rotor baffle (13) stops the end plate (9).

2. The motor rotor according to claim 1, characterized in that: The end plate (9) has an inner circular surface that matches the shaft extension end (6), and the diameter of the inner circular surface of the end plate (9) is larger than the diameter of the shaft extension end (6); and / or the plate body (8) has an inner arc surface that matches the outer peripheral surface of the rotating shaft, and the inner arc surface fits the outer peripheral surface of the rotating shaft.

3. The motor rotor according to claim 1, characterized in that: The rotor baffle (13) and the shaft extension end (6) are interference fit.

4. The motor rotor according to claim 1, characterized in that: A nut (14) is also provided outside the rotor baffle (13), the nut (14) being threadedly connected to the shaft extension end (6), and the nut (14) forms an axial limit for the rotor baffle (13).

5. The motor rotor according to any one of claims 1 to 4, characterized in that: The carbon fiber sheath (2) and the cylinder are interference fit.

6. The motor rotor according to any one of claims 1 to 4, characterized in that: The outer peripheral surface of the cylinder is a smooth surface.

7. The motor rotor according to any one of claims 1 to 4, characterized in that: The first shaft (3) and the second shaft (5) are made of non-magnetic conductive material.

8. A permanent magnet motor, comprising a motor rotor, characterized in that: The motor rotor is the motor rotor according to any one of claims 1 to 7.

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