Rotor assembly and electric machine having the same

Abstract

The application provides a rotor assembly and a motor with the same, wherein the rotor assembly comprises a first baffle, a second baffle, a rotating shaft, a magnetic steel and a current sensor, the first baffle, the second baffle and the magnetic steel are sleeved on the rotating shaft, the magnetic steel is clamped between the first baffle and the second baffle, the first baffle and the second baffle are both conductors, and the current sensor is installed on one of the first baffle and the second baffle. According to the application, since the first baffle, the magnetic steel and the second baffle form a loop, an induced voltage is generated when the rotor assembly rotates at a high speed, and then an induced current is generated in the loop. Since the current sensor is installed on at least one of the two baffles, when the current passes through the current sensor, the current sensor generates an electric signal for transmission, and an external receiver receives the electric signal and then compiles to accurately obtain the real-time temperature of the rotor, thereby solving the problem that the temperature of the rotor of a high-speed motor cannot be accurately measured.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a rotor assembly and a motor having the same. Background Technology

[0002] With the development of motor technology, high-power and ultra-high-speed motors have become the main development direction. Although high-speed motors have advantages such as small size, high speed, and low cost, their design also presents significant challenges. The permanent magnets used in high-speed motors are highly sensitive to temperature; their performance varies at different temperatures. Furthermore, the remanence of permanent magnets is negatively correlated with temperature. When the rotor temperature reaches 180°C, irreversible demagnetization occurs. To address this issue, high-speed motor rotor temperature measurement technology has emerged, measuring the rotor's operating temperature to prevent irreversible demagnetization. However, current technology can only estimate the rotor's outer surface temperature at high speeds through calculation, resulting in significant errors; the values ​​can only be used as references. Summary of the Invention

[0003] Therefore, the present invention provides a rotor assembly that can solve the technical problem that the prior art cannot accurately measure the operating temperature of a high-speed motor rotor.

[0004] To address the aforementioned problems, the present invention provides a rotor assembly comprising a first baffle, a second baffle, a rotating shaft, a magnet, and a current sensor. The first baffle, the second baffle, and the magnet are all sleeved on the rotating shaft, and the magnet is clamped between the first baffle and the second baffle. The first baffle and the second baffle are both conductors, and the first baffle, the magnet, and the second baffle form a circuit. The current sensor is mounted on at least one of the first baffle and the second baffle.

[0005] In some embodiments, at least one of the first baffle and the second baffle has a first receiving cavity, and the current sensor is installed in the first receiving cavity.

[0006] In some embodiments, at least one of the first baffle and the second baffle is further equipped with an electrical signal amplifier.

[0007] In some embodiments, at least one of the first baffle and the second baffle is further provided with a diode; and / or, the resistance of the first baffle and the second baffle is R, where 5 milliohms ≤ R ≤ 10 milliohms.

[0008] In some embodiments, the magnet is made of a mixture of magnetic materials and piezoelectric crystal materials.

[0009] In some embodiments, the magnetic material is made by mixing a permanent magnet material and an epoxy resin.

[0010] In some embodiments, the outer peripheral surface of the magnet is coated with a heat-dissipating coating.

[0011] In some embodiments, the thickness of the heat dissipation coating is H, where 0.002 mm ≤ H ≤ 0.06 mm.

[0012] In some embodiments, the remanence of the magnet is Br, 0.8T≤Br≤1.2T; and / or, the coercivity of the magnet is Hcj, Hcj≥950KA / m.

[0013] The present invention also provides an electric motor, including the aforementioned rotor assembly.

[0014] The rotor assembly and the motor having the same provided by the present invention have the following beneficial effects:

[0015] When the rotor assembly of this application is applied to a high-speed motor, since the first baffle, the magnet, and the second baffle form a circuit, an induced voltage is generated when the rotor assembly rotates at high speed, which in turn generates an induced current in the circuit. Furthermore, because at least one of the first and second baffles is equipped with a current sensor, when the induced current passes through the current sensor, the current sensor generates an electrical signal for transmission. After receiving the electrical signal, an external receiver can accurately determine the real-time temperature of the rotor through processing, thus solving the problem of inaccurate temperature measurement of high-speed motor rotors. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0017] Figure 1 This is a cross-sectional view of the rotor assembly according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the first plate of the first baffle of the rotor assembly according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the second plate of the first baffle of the rotor assembly according to an embodiment of the present invention;

[0020] Figure 4 This is a flowchart illustrating the fabrication process of the magnets in the rotor assembly according to an embodiment of the present invention.

[0021] The reference numerals in the attached figures are as follows:

[0022] 1. First baffle; 2. Second baffle; 3. Rotating shaft; 4. Magnet; 5. Current sensor; 6. First receiving cavity; 7. Electrical signal amplifier; 8. Second receiving cavity. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0025] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0026] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0027] See also Figures 1 to 4As shown, according to an embodiment of the present invention, a rotor assembly is provided, including a first baffle 1, a second baffle 2, a rotating shaft 3, a magnet 4, and a current sensor 5. The first baffle 1, the second baffle 2, and the magnet 4 are all sleeved on the rotating shaft 3, and the magnet 4 is clamped between the first baffle 1 and the second baffle 2. The first baffle 1 and the second baffle 2 are both conductors. The first baffle 1, the magnet 4, and the second baffle 2 form a circuit. At least one of the first baffle 1 and the second baffle 2 is equipped with a current sensor 5.

[0028] In this technical solution, when the rotor assembly is applied to a high-speed motor, the first baffle 1, magnet 4, and second baffle 2 form a circuit. Therefore, when the rotor assembly rotates at high speed, an induced voltage is generated, which in turn generates an induced current in the circuit. Since at least one of the first baffle 1 and second baffle 2 is equipped with a current sensor 5, when the induced current passes through the current sensor 5, the current sensor 5 generates an electrical signal for transmission. An external receiver receives the electrical signal and, through processing, can accurately determine the real-time temperature of the rotor, thus solving the problem of inaccurate temperature measurement of high-speed motor rotors. The magnet 4 is a hollow cylinder, and it can be either clearance-fitted or interference-fitted with the shaft 3. A clearance-fit between the magnet 4 and the shaft 3 reduces the amount of magnetic material used. It is understandable that the higher the rotational speed of the rotor assembly, the greater the induced voltage, and consequently the greater the induced current, resulting in a higher temperature for the rotor assembly.

[0029] See also Figures 1 to 3 As shown, at least one of the first baffle 1 and the second baffle 2 has a first receiving cavity 6 inside, and the current sensor 5 is installed in the first receiving cavity 6.

[0030] In this embodiment, because the rotor assembly is used in a high-speed motor, the rotor assembly rotates at a very high speed during operation. Therefore, the current sensor 5 is subjected to a very large centrifugal force. To prevent the current sensor 5 from being thrown out, a first receiving cavity 6 is constructed within at least one of the first baffle 1 and the second baffle 2. When the current sensor 5 is installed in the first receiving cavity 6, it is equivalent to the current sensor 5 being hidden within the baffle, ensuring the safety of the current sensor 5 regardless of the rotor assembly's rotational speed.

[0031] See Figure 1 As shown, an electrical signal amplifier 7 is also installed on one of the first baffle 1 and the second baffle 2.

[0032] In this technical solution, when the electrical signal amplifier 7 is installed on the baffle, it is equivalent to placing the electrical signal amplifier 7 in the circuit. The electrical signal amplifier 7 can increase the amplitude of the induced current, thereby enhancing the signal of the current sensor 5 and avoiding the disorder of the external receiver's received signal due to the electromagnetic field interference inside the motor, which would lead to chaotic temperature test data.

[0033] Understandably, because the rotor assembly is used in a high-speed motor, its operating speed is extremely high. Consequently, the electrical signal amplifier 7 also experiences significant centrifugal force. To prevent the electrical signal amplifier 7 from being thrown out, a second receiving cavity 8 can be constructed within at least one of the first baffle 1 and the second baffle 2. When the electrical signal amplifier 7 is installed within the second receiving cavity 8, it is equivalent to the electrical signal amplifier 7 being hidden within the baffle, ensuring its safety regardless of the rotor assembly's operating speed.

[0034] It should be noted that the first baffle 1 and the second baffle 2 can both be composed of two plates. One plate has a groove, and the other plate is attached to the plate to cover the groove opening, so that the two grooves become the first receiving cavity 6 and the second receiving cavity 8 on the first baffle 1 and the second baffle 2.

[0035] In one specific implementation, at least one of the first baffle 1 and the second baffle 2 is also equipped with a diode (not shown in the figure).

[0036] In this embodiment, the induced current generated in the circuit flows in multiple directions. When currents from multiple directions pass through the current sensor 5, it significantly impacts the lifespan of the current sensor 5. However, when a diode is installed on at least one of the first baffle 1 and the second baffle 2, it is equivalent to adding a diode to the circuit. The diode can control the direction of the induced current in the circuit, ensuring that the induced current flows only in one direction, thereby extending the lifespan of the current sensor 5. It is understood that the diode can also extend the lifespan of the electrical signal amplifier 7. To ensure the safety of the diode, a receiving cavity can be constructed on at least one of the first baffle 1 and the second baffle 2 to house the diode.

[0037] In one specific implementation, the resistance of the first baffle 1 and the second baffle 2 is R, where 5 milliohms ≤ R ≤ 10 milliohms. This is equivalent to the first baffle 1 and the second baffle 2 being low-impedance baffles, which is beneficial for the formation of the circuit.

[0038] See Figure 4 As shown, magnet 4 is made of a mixture of magnetic material and piezoelectric crystal material.

[0039] In this technical solution, the magnet 4 serves as the excitation part of the motor, forming a permanent magnet pole that cooperates with the stator of the high-speed motor. When the magnet 4 is made of a mixture of magnetic and piezoelectric crystal materials, it ensures that the magnet 4 possesses magnetism while also generating an induced voltage due to the piezoelectric crystal material during rotation. This, in turn, ensures the generation of an induced current in the circuit, ultimately facilitating the accurate measurement of the rotor's operating temperature. It should be noted that the magnet 4 in this application can be referred to as a hybrid piezoelectric magnet.

[0040] Furthermore, the magnetic material is made by mixing permanent magnet material and epoxy resin.

[0041] In this embodiment, when the magnetic material is made by mixing permanent magnet material and epoxy resin, the resulting magnet 4 will have high strength and high modulus due to the presence of epoxy resin, which is beneficial for the magnet 4 to withstand greater circumferential tensile stress under high-speed rotation conditions. The permanent magnet material can be a rare-earth permanent magnet material, such as neodymium iron boron.

[0042] Figure 4 This is a flowchart illustrating the fabrication process of the hybrid piezoelectric magnet in the rotor assembly according to an embodiment of the present invention. The fabrication process of the hybrid piezoelectric magnet is as follows:

[0043] Step 1: Mix epoxy resin and permanent magnet powder to obtain mixed magnetic powder;

[0044] Step 2: Mix the mixed magnetic powder and piezoelectric crystal powder to obtain mixed magnetic induction powder;

[0045] Step 3: The mixed magnetic induction powder is cured and a prototype magnet is formed;

[0046] Step 4: Apply a heat dissipation coating to the outer surface of the magnet prototype to obtain a hybrid piezoelectric magnet.

[0047] As one specific implementation, the outer peripheral surface of the magnet 4 is coated with a heat dissipation coating.

[0048] In this technical solution, because the rotor assembly is used in a high-speed motor, the rotor assembly has a high rotational speed and generates a lot of heat. By coating the outer peripheral surface of the magnet 4 with a heat dissipation coating, the heat dissipation of the magnet 4 is facilitated, and the irreversible demagnetization of the magnet 4 due to high operating temperature is prevented.

[0049] Furthermore, the thickness of the heat dissipation coating is H, where 0.002mm ≤ H ≤ 0.06mm.

[0050] In this embodiment, an excessively thick heat dissipation coating will affect the generation of induced voltage, while an excessively thin coating will result in poor heat dissipation. Experimental results show that a heat dissipation coating thickness between 0.002 mm and 0.06 mm can balance the generation of induced voltage and ensure effective heat dissipation. The heat dissipation coating can be made of epoxy resin or graphene. The heat dissipation coating can be applied to the outer surface of the magnet 4 using methods such as PVD, spraying, dipping, or brushing.

[0051] In one specific implementation, the remanence of magnet 4 is Br, where 0.8T≤Br≤1.2T.

[0052] In this technical solution, when the residual magnetism of the magnet 4 is between 0.8T and 1.2T, it can be ensured that the high-speed motor used in the rotor assembly has high motor efficiency.

[0053] Furthermore, the coercivity of magnet 4 is Hcj, where Hcj ≥ 950KA / m.

[0054] In this embodiment, the level of coercivity directly affects the stability and demagnetization of the magnet 4. Higher coercivity can enable the magnet to achieve sufficiently stable magnetization in the direction of a smaller thickness, while reducing the chance of reverse demagnetization. Therefore, the coercivity of the magnet 4 used in this application is above 950KA / m.

[0055] The present invention also provides an electric motor, including the aforementioned rotor assembly. The electric motor may be a magnetic levitation high-speed motor, a cyclone levitation high-speed motor, a bearingless high-speed motor, etc., and the rated speed of the motor is above 10,000 rpm.

[0056] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A rotor assembly, characterized in that, The assembly includes a first baffle (1), a second baffle (2), a rotating shaft (3), a magnet (4), and a current sensor (5). The first baffle (1), the second baffle (2), and the magnet (4) are all sleeved on the rotating shaft (3), and the magnet (4) is clamped between the first baffle (1) and the second baffle (2). The first baffle (1) and the second baffle (2) are both conductors. The magnet (4) is made of a mixture of magnetic material and piezoelectric crystal material. The first baffle (1), the magnet (4), and the second baffle (2) form a circuit. The current sensor (5) is installed on at least one of the first baffle (1) and the second baffle (2). When the rotor assembly rotates, it generates an induced voltage to induce a current in the circuit.

2. The rotor assembly according to claim 1, characterized in that, At least one of the first baffle (1) and the second baffle (2) has a first receiving cavity (6) inside, and the current sensor (5) is installed in the first receiving cavity (6).

3. The rotor assembly according to claim 1, characterized in that, An electrical signal amplifier (7) is also installed on at least one of the first baffle (1) and the second baffle (2).

4. The rotor assembly according to claim 1, characterized in that, A diode is also installed on at least one of the first baffle (1) and the second baffle (2); and / or, the resistance of the first baffle (1) and the second baffle (2) is R, 5 milliohms ≤ R ≤ 10 milliohms.

5. The rotor assembly according to claim 1, characterized in that, The magnetic material is made by mixing permanent magnet material and epoxy resin.

6. The rotor assembly according to any one of claims 1 to 4, characterized in that, The outer peripheral surface of the magnet (4) is coated with a heat dissipation coating.

7. The rotor assembly according to claim 6, characterized in that, The thickness of the heat dissipation coating is H, where 0.002mm ≤ H ≤ 0.06mm.

8. The rotor assembly according to any one of claims 1 to 4, characterized in that, The remanence of the magnet (4) is Br, 0.8T≤Br≤1.2T; and / or the coercivity of the magnet (4) is Hcj, Hcj≥950KA / m.

9. An electric motor, characterized in that, Includes the rotor assembly as described in any one of claims 1 to 8.

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