Rotor assembly and motor with same

Abstract

The invention provides a rotor assembly and a motor with the same, the rotor assembly comprises a first baffle plate, a second baffle plate, a rotating shaft, magnetic steel and a current sensor, the rotating shaft is sleeved with the first baffle plate, the second baffle plate and the magnetic steel, the magnetic steel is clamped between the first baffle plate and the second baffle plate, the first baffle plate and the second baffle plate are conductors, and the current sensor is arranged on the rotating shaft. The current sensor is mounted on one of the first baffle and the second baffle. According to the invention, because the first baffle plate, the magnetic steel and the second baffle plate form a loop, when the rotor assembly rotates at a high speed, an induced voltage is generated, and then an induced current is generated in the loop. At least one of the two baffles is provided with a current sensor, so that 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 the electric signal to accurately obtain the real-time temperature of the rotor. Therefore, the problem that the high-speed motor rotor is difficult to accurately measure the temperature is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a rotor assembly and a motor having the same. Background Art

[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 the advantages of small size, high speed and low cost, they also face great challenges in design. The permanent magnets used in high-speed motors are very sensitive to temperature. The performance of permanent magnets at different temperatures is inconsistent. The remanence of permanent magnets is negatively correlated with temperature. When the temperature of the rotor reaches 180°C, the motor will undergo irreversible demagnetization. In response to this problem, high-speed motor rotor temperature measurement technology came into being. It measures the operating temperature of the motor rotor to avoid irreversible demagnetization of the motor. However, the existing technology can only estimate the outer surface temperature of the motor rotor at high speed by calculation, which has a large error and the value can only be used as a reference. Summary of the invention

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

[0004] In order to solve the above problems, the present invention provides a rotor assembly, including 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, the first baffle, the magnet and the second baffle form a loop, and the current sensor is installed on at least one of the first baffle and the second baffle.

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

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

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

[0008] In some embodiments, the magnetic steel is made by mixing magnetic material and piezoelectric crystal material.

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

[0010] In some embodiments, a heat dissipation coating is coated on the outer peripheral surface of the magnetic steel.

[0011] In some embodiments, the heat dissipation coating has a thickness H, 0.002 mm ≤ H ≤ 0.06 mm.

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

[0013] The present invention also provides a motor, comprising the above-mentioned rotor assembly.

[0014] The present invention provides a rotor assembly and a motor having the same, which have the following beneficial effects:

[0015] When the rotor assembly of the present application is applied to a high-speed motor, since the first baffle, the magnetic steel and the second baffle form a loop, an induced voltage will be generated when the rotor assembly rotates at a high speed, and then an induced current will be generated in the loop. In addition, since a current sensor is installed on at least one of the first baffle and the second baffle, when the induced current passes through the current sensor, the current sensor will generate an electrical signal for transmission, and the external receiver can accurately obtain the real-time temperature of the rotor by compiling after receiving the electrical signal, thereby solving the problem of high-speed motor rotors being difficult to accurately measure temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

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

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

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

[0020] Figure 4 The present invention is a flow chart of the preparation of magnetic steel for a rotor assembly according to an embodiment of the present invention.

[0021] The reference numerals are as follows:

[0022] 1. First baffle; 2. Second baffle; 3. Rotating shaft; 4. Magnetic steel; 5. Current sensor; 6. First accommodating chamber; 7. Electrical signal amplifier; 8. Second accommodating chamber. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

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

[0026] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present 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 magnetic steel 4 and a current sensor 5. The first baffle 1, the second baffle 2 and the magnetic steel 4 are all sleeved on the rotating shaft 3, and the magnetic steel 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 magnetic steel 4 and the second baffle 2 form a loop, and the current sensor 5 is installed on at least one of the first baffle 1 and the second baffle 2.

[0028] In this technical solution, when the rotor assembly is applied to a high-speed motor, since the first baffle 1, the magnetic steel 4 and the second baffle 2 form a loop, an induced voltage will be generated when the rotor assembly rotates at a high speed, and then an induced current will be generated in the loop. Because a current sensor 5 is installed on at least one of the first baffle 1 and the second baffle 2, when the induced current passes through the current sensor 5, the current sensor 5 will generate an electrical signal for transmission. After the external receiver receives the electrical signal, it can accurately obtain the real-time temperature of the rotor by compiling it, thereby solving the problem that the high-speed motor rotor is not easy to accurately measure the temperature. Among them, the magnetic steel 4 is a hollow cylinder, and the magnetic steel 4 can be a clearance fit or an interference fit with the rotating shaft 3. When the magnetic steel 4 is clearance fit with the rotating shaft 3, the effect of reducing the amount of magnetic material can be achieved. It can be understood that the higher the rotation speed of the rotor assembly, the greater the induced voltage generated, and then the greater the induced current generated, and the higher the temperature of the rotor assembly.

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

[0030] In this embodiment, because the rotor assembly is applied to a high-speed motor, the rotation speed of the rotor assembly is very high in the working state, and the current sensor 5 is subjected to a very large centrifugal force. In order to prevent the current sensor 5 from being thrown out, a first accommodating cavity 6 is constructed in at least one of the first baffle 1 and the second baffle 2. When the current sensor 5 is installed in the first accommodating cavity 6, it is equivalent to that the current sensor 5 is hidden in the baffle, so no matter how high the rotation speed of the rotor assembly is, the current sensor 5 is in a very safe situation.

[0031] See also Figure 1 As shown, an electric signal amplifier 7 is also installed on one of the first baffle plate 1 and the second baffle plate 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 loop, and the electrical signal amplifier 7 can increase the amplitude of the induced current, thereby enhancing the signal of the current sensor 5 and avoiding confusion in the temperature test data caused by the external receiver receiving the signal disorder due to the internal electromagnetic field interference of the motor.

[0033] It is understandable that, because the rotor assembly is applied to a high-speed motor, the rotation speed of the rotor assembly is very high in the working state, and the electric signal amplifier 7 also has to bear a very large centrifugal force. In order to prevent the electric signal amplifier 7 from being thrown out, a second accommodating cavity 8 can also be constructed in at least one of the first baffle 1 and the second baffle 2. When the electric signal amplifier 7 is installed in the second accommodating cavity 8, it is equivalent to the electric signal amplifier 7 being hidden in the baffle, so no matter how high the rotation speed of the rotor assembly is, the electric signal amplifier 7 is in a very safe situation.

[0034] It should be noted that the first baffle 1 and the second baffle 2 can be composed of two plates, one of which is provided with a groove, and the other plate is buckled onto the plate to cover the notch of the groove, so that the two grooves become the first accommodating cavity 6 and the second accommodating cavity 8 on the first baffle 1 and the second baffle 2.

[0035] As a specific implementation manner, a diode (not shown in the figure) is further installed on at least one of the first baffle 1 and the second baffle 2 .

[0036] In this embodiment, the induced current generated in the loop flows in multiple directions. When the current in multiple directions passes through the current sensor 5, it will have a greater impact on the service life of the current sensor 5. 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 loop. The diode can control the flow direction of the induced current in the loop so that the induced current can only flow in one direction, thereby extending the service life of the current sensor 5. It can be understood that the setting of the diode can also extend the service life of the electrical signal amplifier 7. In order to ensure the safety of the diode, a receiving cavity can also be constructed on at least one of the first baffle 1 and the second baffle 2, and the diode can be installed in the receiving cavity.

[0037] As a specific implementation, the resistance of the first baffle 1 and the second baffle 2 is R, 5 milliohms ≤ R ≤ 10 milliohms, which is equivalent to the first baffle 1 and the second baffle 2 being low-impedance baffles, which is conducive to the formation of a loop.

[0038] See also Figure 4 As shown, the magnetic steel 4 is made by mixing magnetic material and piezoelectric crystal material.

[0039] In this technical solution, the magnetic steel 4 is used as the excitation part of the motor to form a permanent magnetic pole that matches the stator of the high-speed motor. When the magnetic steel 4 is made of a mixture of magnetic material and piezoelectric crystal material, it can ensure that the magnetic steel 4 has magnetism, and because of the piezoelectric crystal material, it can ensure that the magnetic steel 4 will generate an induced voltage when rotating, and then ensure that an induced current is generated in the circuit, and ultimately it is conducive to accurately measuring the working temperature of the rotor. It should be noted that the magnetic steel 4 of this application can be called a hybrid piezoelectric magnetic steel.

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

[0041] In this embodiment, when the magnetic material is made by mixing a permanent magnetic material and an epoxy resin, the magnetic steel 4 finally formed will have the characteristics of high strength and high modulus due to the epoxy resin component, which is conducive to the magnetic steel 4 being able to withstand greater circumferential tensile stress under high-speed rotation conditions. Among them, the permanent magnetic material can be a rare earth permanent magnetic material, such as neodymium iron boron.

[0042] Figure 4 FIG. 1 is a flow chart of preparing a hybrid piezoelectric magnetic steel of a rotor assembly according to an embodiment of the present invention. The preparation process of the hybrid piezoelectric magnetic steel is as follows:

[0043] Step 1: Mixing epoxy resin and permanent magnetic powder to prepare mixed magnetic powder;

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

[0045] Step 3: solidify the mixed magnetic induction powder and make a magnetic steel prototype;

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

[0047] As a specific implementation, a heat dissipation coating is coated on the outer peripheral surface of the magnetic steel 4 .

[0048] In this technical solution, because the rotor assembly is used in a high-speed motor, the rotation speed of the rotor assembly is relatively high and the heat generated is relatively large. By applying a heat dissipation coating on the outer peripheral surface of the magnetic steel 4, it is beneficial to the heat dissipation of the magnetic steel 4 and avoids irreversible demagnetization of the magnetic steel 4 due to the high operating temperature.

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

[0050] In this embodiment, if the heat dissipation coating is too thick, it will affect the generation of induced voltage, and if the heat dissipation coating is too thin, the heat dissipation effect will be poor. Experimental results show that when the thickness of the heat dissipation coating is between 0.002 mm and 0.06 mm, it can take into account both the generation of induced voltage and the guarantee of heat dissipation effect. The material of the heat dissipation coating can be epoxy resin or graphene. The heat dissipation coating can be applied to the outer peripheral surface of the magnetic steel 4 by PVD, spraying, dipping, brushing, etc.

[0051] As a specific implementation, the remanence of the magnetic steel 4 is Br, 0.8T≤Br≤1.2T.

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

[0053] Furthermore, the coercive force of the magnetic steel 4 is Hcj, and Hcj≥950KA / m.

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

[0055] The present invention also provides a motor, including the aforementioned rotor assembly, the motor can be a magnetic levitation high-speed motor, a cyclone floating high-speed motor, a bearingless high-speed motor, etc., and the rated speed of the motor is above 10000rpm.

[0056] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0057] The above are only 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 shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. 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 invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A rotor assembly, characterized in that: The invention comprises a first baffle (1), a second baffle (2), a rotating shaft (3), a magnetic steel (4) and a current sensor (5); the first baffle (1), the second baffle (2) and the magnetic steel (4) are all sleeved on the rotating shaft (3), and the magnetic steel (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 magnetic steel (4) and the second baffle (2) form a circuit; and the current sensor (5) is installed on at least one of the first baffle (1) and the second baffle (2).

2. The rotor assembly according to claim 1, characterized in that A first accommodating cavity (6) is constructed in at least one of the first baffle plate (1) and the second baffle plate (2), and the current sensor (5) is installed in the first accommodating cavity (6).

3. The rotor assembly according to claim 1, characterized in that: An electric 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 mounted on at least one of the first baffle plate (1) and the second baffle plate (2); and / or the resistance of the first baffle plate (1) and the second baffle plate (2) is R, 5 milliohms ≤ R ≤ 10 milliohms.

5. The rotor assembly according to any one of claims 1 to 4, characterized in that: The magnetic steel (4) is made by mixing magnetic material and piezoelectric crystal material.

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

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

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

9. The rotor assembly according to any one of claims 1 to 4, characterized in that: The remanence of the magnetic steel (4) is Br, 0.8T≤Br≤1.2T; and / or the coercive force of the magnetic steel (4) is Hcj, Hcj≥950KA / m.

10. A motor, characterized in that: A rotor assembly comprising any one of claims 1 to 9.

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