Equipment for evaluating concentricity of stator and rotor of six-phase motor through induced current

Abstract

The utility model relates to the technical field of steering systems, in particular to equipment for evaluating concentricity of a stator and a rotor of a six-phase motor through induced current. A device for evaluating concentricity of a stator and a rotor of a six-phase motor through induced current comprises a servo motor, couplings, a torque and rotating speed measuring instrument and a fixing tool, and is characterized in that a driving shaft of a tested motor is connected with one end of the torque and rotating speed measuring instrument through a first coupling; the other end of the torque rotating speed measuring instrument is connected with a driving shaft of the servo motor through a coupling II; u, V and W phase windings of the tested motor are respectively connected in series with the current sensor through lines to form a concentricity test circuit of a loop. Compared with the prior art, the equipment for evaluating the concentricity of the stator and the rotor of the six-phase motor through induction current is provided, and current test is used as a reference standard for judging the mechanical concentricity.

Description

Technical Field

[0001] The utility model relates to the technical field of steering systems, in particular to a device for evaluating the concentricity of a stator and rotor of a six-phase motor through an induced current. Background Art

[0002] Currently, most automotive electronic power steering (EPS) motors use permanent magnet synchronous motors. The power steering system is a functional safety component with high reliability requirements. The six-phase motor can be understood as a combination of two three-phase motor models. When one three-phase motor model fails, the other model can still work normally.

[0003] Therefore, the six-phase motor improves the reliability and stability of the EPS system in automotive applications. Currently, six-phase AC permanent magnet motors are widely used in EPS systems. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the utility model provides a device for evaluating the stator and rotor concentricity of a six-phase motor through induced current, and uses current testing as a reference standard for judging the mechanical concentricity.

[0005] To achieve the above purpose, a device is designed to evaluate the concentricity of the stator and rotor of a six-phase motor by induced current, including a servo motor, a coupling, a torque and speed measuring instrument, and a fixed tooling. The device is characterized in that: the driving shaft of the motor under test is connected to one end of the torque and speed measuring instrument through coupling 1, and the other end of the torque and speed measuring instrument is connected to the driving shaft of the servo motor through coupling 2; the U, V, and W phase windings of the motor under test are respectively connected through line series current sensors to form a loop concentricity test circuit.

[0006] The U-phase winding of the motor under test includes U1 and U2, the V-phase winding includes V1 and V2, and the W-phase winding includes W1 and W2.

[0007] The concentricity test circuit includes a current sensor, a resistor, and an inductor. U1 of the motor under test is connected to one end of resistor one, the other end of resistor one is connected to one end of inductor one, the other end of inductor one is connected to U2 of the motor under test, and current sensor one is connected in series on the line between U1 of the motor under test and resistor one; V1 of the motor under test is connected to one end of resistor two, the other end of resistor two is connected to one end of inductor two, the other end of inductor two is connected to V2 of the motor under test, and current sensor two is connected in series on the line between inductor two and V2 of the motor under test; W1 of the motor under test is connected to one end of resistor three, the other end of resistor three is connected to one end of inductor three, the other end of inductor three is connected to W2 of the motor under test, and current sensor three is connected in series on the line between W1 of the motor under test and resistor three.

[0008] The motor under test is fixed on the test bench by a fixing fixture.

[0009] The servo motor and the torque and speed measuring instrument are respectively fixed on the test bench through connecting pieces.

[0010] Compared with the prior art, the utility model provides a device for evaluating the concentricity of the stator and rotor of a six-phase motor through induced current, and uses the current test as a reference standard for judging the mechanical concentricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is the structural connection diagram of the utility model.

[0012] Figure 2 This is a concentricity test circuit diagram in the utility model.

[0013] Figure 3 This is a curve diagram showing the relationship between the concentricity of the motor stator and rotor and the induced current value. DETAILED DESCRIPTION

[0014] The utility model is further described below with reference to the accompanying drawings.

[0015] The EPS motor structure can be divided into three parts: stator assembly, rotor assembly, and front cover. The front cover and stator assembly are fixed together by laser welding (weld). The shaft of the EPS motor is rigidly connected with the rotor core, A-end bearing, and B-end bearing to form a rotor assembly; the front cover and rotor assembly are fixed together by riveting the A-end bearing; the stator core, housing, and winding form a stator assembly. The stator assembly generates an armature magnetic field through alternating current, which interacts with the permanent magnet excitation magnetic field of the rotor assembly, converting electrical energy into mechanical energy to output torque while the magnetic field rotates.

[0016] There is a gap between the stator and rotor of the motor, which is called the air gap. When the motor is running, if the concentricity of the stator and rotor is poor, the air gap magnetic field of the motor will be unevenly distributed, causing the torque output of the motor to fluctuate and aggravate the vibration of the motor. Therefore, the concentricity of the stator and rotor is one of the main indicators of motor design and manufacturing. Since the motor is a closed space, it is difficult to test the actual state of the concentricity of the stator and rotor of the motor after the stator and rotor are assembled.

[0017] At present, the method in the industry is to determine whether the concentricity of the stator and rotor of the motor is good or not by the back electromotive force balance. The worse the concentricity of the stator and rotor, the higher the imbalance rate. The specific test method is to drag the motor to rotate at a constant speed (usually 1000rpm), and calculate the imbalance by testing six parameters such as the line voltage U1-U6 between U1 and V1, U1 and W1, V1 and W1, U2 and V2, U2 and W2, and V2 and W2. Divide the difference between the maximum and minimum values ​​by the average value. µ=(Umax -Umin) / Uaverage.

[0018] However, for device connection, six wiring harnesses are required to implement the testing of six parameters, which greatly affects production efficiency, especially when testing on the production line.

[0019] The utility model uses current testing as a reference standard for judging the mechanical concentricity. A six-phase motor has six phases: U1, V1, W1, U2, V2, and W2. The same-phase "U1, U2", "V1, V2", and "W1, W2" are connected to form a loop. After the motor is dragged, if there is eccentricity, an induced current will be formed in the loop, and the greater the eccentricity, the greater the induced current. The current values ​​in the three loops can be obtained through three current sensors. The maximum value Imax of these three currents can be used as a standard for judging the concentricity state. The larger the Imax value, the worse the concentricity.

[0020] like Figure 1 , Figure 2 As shown, the driving shaft of the motor 5 under test is connected to one end of the torque and speed measuring instrument 3 through a coupling 2, and the other end of the torque and speed measuring instrument 3 is connected to the driving shaft of the servo motor 1 through a coupling 2 7; the U, V, and W phase windings of the motor 5 under test are respectively connected through a line series current sensor 6 to form a loop concentricity test circuit.

[0021] The U-phase winding of the motor 5 under test includes U1 and U2, the V-phase winding includes V1 and V2, and the W-phase winding includes W1 and W2.

[0022] The concentricity test circuit includes a current sensor, a resistor, and an inductor. U1 of the motor 5 under test is connected to one end of a resistor R1, the other end of the resistor R1 is connected to one end of an inductor L1, the other end of the inductor L1 is connected to U2 of the motor 5 under test, and a current sensor I1 is connected in series on the line between U1 of the motor 5 under test and the resistor R1; V1 of the motor 5 under test is connected to one end of a resistor R2, the other end of the resistor R2 is connected to one end of an inductor L2, the other end of the inductor L2 is connected to V2 of the motor 5 under test, and a current sensor I2 is connected in series on the line between the inductor L2 and V2 of the motor 5 under test; W1 of the motor 5 under test is connected to one end of a resistor R3, the other end of the resistor R3 is connected to one end of an inductor L3, the other end of the inductor L3 is connected to W2 of the motor 5 under test, and a current sensor I3 is connected in series on the line between W1 of the motor 5 under test and the resistor R3.

[0023] The motor 5 under test is fixed on the test bench by means of a fixing fixture 4 .

[0024] The servo motor 1 and the torque and speed measuring instrument 3 are respectively fixed on the test bench through connecting pieces.

[0025] A current sensor is a detection device that can sense the information of the measured current and can transform the sensed information into an electrical signal or other required form of information output that meets certain standards according to certain rules to meet the requirements of information transmission, processing, storage, display, recording and control. The current sensor used in this article is LEM brand, model IT 200-S, and the maximum range is 200A.

[0026] The testing principle of the utility model is consistent with the testing principle of back electromotive force imbalance, both of which are that poor stator and rotor concentricity will lead to a voltage difference in the symmetrical phase voltage. The asymmetry test of the back electromotive force is to test the voltage difference of each terminal and compare it with the eccentricity; the asymmetry test of the current is to connect the symmetrical phase terminals to form a loop. Due to the existence of the voltage difference, a current will be formed in the loop, and the size of the current can be equivalent to the voltage difference. The greater the eccentricity, the greater the voltage difference of the symmetrical phase, and the greater the current after the terminals are connected to form a loop.

[0027] Note on current: Which of the three values ​​of I1, I2, and I3 is the largest is random and depends on the direction of the motor stator eccentricity. According to the node current method, the space vector sum of I1, I2, and I3 is 0.

[0028] The utility model only needs three wire harnesses and three current parameters. Compared with the six wire harnesses and six parameters of the current test scheme in the industry, the production cycle and the simplicity of operation can be improved, and the test efficiency and analysis efficiency can be effectively improved.

[0029] The specific implementation method is to test IA\IB\IC in current clamp A, current clamp B, and current clamp C after the motor is driven to 1000rpm, and take the maximum value among the three to determine the degree of eccentricity of the stator and rotor. The larger the maximum current value among the three, the more serious the eccentricity of the stator and rotor.

[0030] Through actual testing, the relationship between motor eccentricity and current balance value can be obtained, such as Figure 3 As shown, the relationship curves of the induced current value and concentricity of different motors have the same trend, but the specific value depends on the performance of the motor. For the test motor, the concentricity of the motor stator and rotor is 0.15, and the corresponding maximum induced current is 0.9A.

Claims

1. A device for evaluating the concentricity of the stator and rotor of a six-phase motor by induction current, comprising a servo motor, a coupling, a torque and speed measuring instrument, and a fixed tool, characterized in that: The drive shaft of the motor (5) under test is connected to one end of the torque and speed measuring instrument (3) through a coupling 1 (2), and the other end of the torque and speed measuring instrument (3) is connected to the drive shaft of the servo motor (1) through a coupling 2 (7); the U, V, and W phase windings of the motor (5) under test are respectively connected through line series current sensors (6) to form a loop concentricity test circuit.

2. The device for evaluating the concentricity of the stator and rotor of a six-phase motor by induction current according to claim 1, characterized in that: The U-phase winding of the motor (5) under test includes U1 and U2, the V-phase winding includes V1 and V2, and the W-phase winding includes W1 and W2.

3. The device for evaluating the concentricity of the stator and rotor of a six-phase motor by induction current according to claim 1, characterized in that: The concentricity test circuit comprises a current sensor, a resistor, and an inductor; U1 of the motor (5) under test is connected to one end of resistor 1 (R1), the other end of resistor 1 (R1) is connected to one end of inductor 1 (L1), the other end of inductor 1 (L1) is connected to U2 of the motor (5) under test; a current sensor 1 (I1) is connected in series on the line between U1 of the motor (5) under test and resistor 1 (R1); V1 of the motor (5) under test is connected to one end of resistor 2 (R2), the other end of resistor 2 (R2) is connected to inductor 2 (L2) one end of the measured motor (5), the other end of the inductor 2 (L2) is connected to V2 of the measured motor (5), and the line between the inductor 2 (L2) and V2 of the measured motor (5) is connected in series with the current sensor 2 (I2); W1 of the measured motor (5) is connected to one end of the resistor 3 (R3), the other end of the resistor 3 (R3) is connected to one end of the inductor 3 (L3), the other end of the inductor 3 (L3) is connected to W2 of the measured motor (5), and the line between the W1 of the measured motor (5) and the resistor 3 (R3) is connected in series with the current sensor 3 (I3).

4. The device for evaluating the concentricity of the stator and rotor of a six-phase motor by induction current according to claim 1, characterized in that: The motor under test (5) is fixed on the test bench by means of a fixing fixture (4).

5. The device for evaluating the concentricity of the stator and rotor of a six-phase motor by induction current according to claim 1, characterized in that: The servo motor (1) and the torque and speed measuring instrument (3) are respectively fixed on the test bench via connecting pieces.

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