阅读说明：本技术 基于石墨烯镀层的电动机轴传感器 (Motor shaft sensor based on graphene coating ) 是由 吴振升 桂峻峰 王鑫祺 于 2020-06-05 设计创作，主要内容包括：本发明涉及一种基于石墨烯镀层的电动机轴传感器,包括石墨烯镀层、探棒和输出电路；石墨烯镀层镀在电动机传动轴的外表面上；探棒包括刚性金属探测器和内置压电晶体,刚性金属探测器通过支座与电动机的定子固定连接,刚性金属探测器的一端与所述石墨烯镀层保持接触,刚性金属探测器的另一端与内置压电晶体连接；内置压电晶体用于感知所述刚性金属探测器从被测电机传动轴上传来的压力,并输出对应的电荷信号；输出电路用于接收所述电荷信号,并将所述电荷信号转换为电信号进行输出。该基于石墨烯镀层的电动机轴传感器具有结构简单,体积小,质量轻,精度高,性能可靠,可适用于高精度的电动机测试,特别是微特电动机测试。(The invention relates to a motor shaft sensor based on a graphene coating, which comprises the graphene coating, a probe and an output circuit; the graphene coating is plated on the outer surface of the motor transmission shaft; the probe comprises a rigid metal detector and a built-in piezoelectric crystal, the rigid metal detector is fixedly connected with a stator of the motor through a support, one end of the rigid metal detector is in contact with the graphene coating, and the other end of the rigid metal detector is connected with the built-in piezoelectric crystal; the built-in piezoelectric crystal is used for sensing the pressure transmitted by the rigid metal detector from the transmission shaft of the tested motor and outputting a corresponding charge signal; the output circuit is used for receiving the charge signal and converting the charge signal into an electric signal for outputting. The motor shaft sensor based on the graphene coating has the advantages of simple structure, small size, light weight, high precision and reliable performance, and is suitable for high-precision motor tests, particularly micro-special motor tests.)

1. A motor shaft sensor based on graphene coating, comprising: the device comprises a graphene coating, a probe and an output circuit;

the graphene coating is plated on the outer surface of the motor transmission shaft;

the probe comprises a rigid metal detector and a built-in piezoelectric crystal, the rigid metal detector is fixedly connected with a stator of the motor through a support, one end of the rigid metal detector is in contact with the graphene coating, and the other end of the rigid metal detector is connected with the built-in piezoelectric crystal;

the built-in piezoelectric crystal is used for sensing the pressure transmitted by the rigid metal detector from the transmission shaft of the tested motor and outputting a corresponding charge signal;

the output circuit is used for receiving the charge signal and converting the charge signal into an electric signal for outputting.

2. The graphene-plating-based motor shaft sensor according to claim 1, wherein the graphene plating has an axial length set to 1 to 10 mm.

3. The graphene-plated motor shaft sensor according to claim 1, wherein the number of graphene plating layers is 10 or more.

4. The graphene-plated motor shaft sensor according to claim 1, wherein the graphene plating has a cross-sectional shape of saw teeth, and the saw teeth are arranged in a continuous congruent triangle and are circumferentially distributed.

5. The graphene-plated motor shaft sensor according to claim 1, wherein the rigid metal detector is made of a rigid metal material.

6. The graphene-plated motor shaft sensor according to claim 4, wherein one end of the rigid metal probe, which is in contact with the graphene plating, is a cone, the tip of the cone is inserted into the gap of the saw tooth, and the side surface of the cone is in contact with the side surface of the saw tooth.

7. The graphene-plating-based motor shaft sensor according to claim 1, wherein the output circuitry comprises electronic circuitry for a/D conversion and signal output functions, the output circuitry being configured to output as an electrical signal throughout the sensor.

8. The graphene-plating-based motor shaft sensor according to claim 1, further comprising a computer connected to the output circuit;

and the computer is used for receiving the output electric signal of the output circuit and calculating the rotating speed of the motor.

Technical Field

The invention relates to the technical field of sensors, in particular to a motor shaft sensor based on a graphene coating.

Background

The motor is applied and wide power equipment thereof, is an indispensable basic product in various fields such as industrial automation, agricultural modernization, weapon equipment modernization, office automation, family modernization and the like, has a very wide application range, and is further expanded along with the economic development degree and the technical progress. The performance of various motors is very different, and the performance parameters are difficult to be uniformly clarified. Generally, driving machines focus on performance criteria during operation and start-up, and control micro-machines focus on static and dynamic performance parameters. Description of various properties requires measurement of operating parameters of the motor, mainly including rotational speed, torque, rotor position, etc. At present, the accurate measurement of the parameters is based on methods of mechanical stress, photoelectricity and the like, the structure is complex, the materials are heavy, and the method is difficult to be suitable for high-precision motor test, particularly for micro-special motor test.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a motor shaft sensor based on a graphene coating, which has the advantages of simple structure, small volume, light weight, high precision and reliable performance, and is suitable for high-precision motor tests, particularly for micro-special motor tests.

Therefore, the technical scheme is that the motor shaft sensor based on the graphene coating comprises the graphene coating, a probe and an output circuit; the graphene coating is plated on the outer surface of the motor transmission shaft; the probe comprises a rigid metal detector and a built-in piezoelectric crystal, the rigid metal detector is fixedly connected with a stator of the motor through a support, one end of the rigid metal detector is in contact with the graphene coating, and the other end of the rigid metal detector is connected with the built-in piezoelectric crystal; the built-in piezoelectric crystal is used for sensing the pressure transmitted by the rigid metal detector from the transmission shaft of the tested motor and outputting a corresponding charge signal; the output circuit is used for receiving the charge signal and converting the charge signal into an electric signal for outputting.

Preferably, the graphene plating layer has an axial length of 1 to 10 mm.

Preferably, the number of graphene plating layers is 10 or more.

Preferably, the graphene plating layer has a saw-tooth cross-sectional shape, and the saw-teeth are arranged in a continuous congruent triangle and are circumferentially distributed.

Preferably, the rigid metal detector is made of a rigid metal material.

Preferably, one end of the rigid metal probe, which is in contact with the graphene plating layer, is a cone, a tip of the cone is inserted into a gap of the saw tooth, and a side surface of the cone is in contact with a side surface of the saw tooth.

Preferably, the output circuit comprises electronic circuitry for a/D conversion and signal output functions, the output circuit being for output as an electrical signal for the entire sensor.

Preferably, the motor shaft sensor based on the graphene coating further comprises a computer, and the computer is in communication connection with the output circuit; and the computer is used for receiving the output electric signal of the output circuit and calculating the rotating speed of the motor.

The technical scheme of the invention has the following advantages:

1. compared with the prior art, the motor shaft sensor based on the graphene coating can more accurately sense the motion information on the motor shaft; graphene is the thinnest and the hardest nano material in the world at present, and the performance parameters of a motor shaft are converted based on a coating of the graphene material on a motor transmission shaft, so that the graphene-based motor shaft has the characteristics of small influence on the operation of the motor, high measurement accuracy and the like.

2. The motor shaft sensor based on the graphene coating has the advantages of simple structure, small volume, light weight, high precision and reliable performance, and can be suitable for high-precision motor tests, particularly for micro-special motor tests.

3. According to the motor shaft sensor based on the graphene coating, the graphene has good hardness and can be finely processed into the graphene coating with a saw-toothed structure, the rigid metal detector is periodically displaced under the action of the coating, so that the piezoelectric crystal is driven to generate periodic charge signals, and the periodic charge signals are transmitted to a computer through an output circuit, therefore, the rotating speed and the torque of the motor can be accurately calculated, the real-time position of a rotor and the like can be judged, and the motor shaft sensor based on the graphene coating has important significance for accurately measuring and controlling the motor.

4. The motor shaft sensor based on the graphene coating provided by the invention has extremely small measurement error, and the measurement error of the basic rotating speed can be lower than one millionth.

Drawings

In order 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 described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a motor shaft sensor based on graphene coating, which is provided by the invention, mounted on a motor;

FIG. 2 is a schematic diagram of a graphene-plated-based motor shaft sensor provided by the invention;

FIG. 3 is a front view of a graphene-plated based motor shaft sensor provided by the present invention;

FIG. 4 is an enlarged view taken at I of FIG. 3;

FIG. 5 is a schematic diagram showing the variation frequency cycle of the output signal of the motor shaft sensor based on graphene coating provided by the invention;

1-a stator; 2-stator lamination group; 3-winding; 5-a rotor; 7-a transmission shaft; 8-a bearing; 9-a housing; 100-motor shaft sensors based on graphene coatings;

11-graphene plating; 12-an output circuit; 13-a rigid metal probe; 14-built-in piezoelectric crystal; 15-a sleeve; 16-electrode slice; 17-a terminal post; 18-a support; 19-saw teeth; 20-cone.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 2 to 4, a motor shaft sensor 100 based on graphene coating includes a graphene coating 11, a probe and an output circuit 12; the graphene plating layer 11 is plated on the outer surface of the motor transmission shaft 7; the probe comprises a rigid metal detector 13 and a built-in piezoelectric crystal 14, wherein the rigid metal detector 13 is fixedly connected with a stator of the motor through a support, one end of the rigid metal detector 13 is in contact with the graphene coating 11, and the other end of the rigid metal detector 13 is connected with the built-in piezoelectric crystal 14; the built-in piezoelectric crystal 14 is used for sensing the pressure transmitted by the rigid metal detector 13 from the transmission shaft 7 of the tested motor and outputting a corresponding charge signal; the output circuit is used for receiving the charge signal and converting the charge signal into an electric signal for outputting.

Fig. 1 shows a basic structure of an electric motor, which includes a stator 1, a rotor 5, a transmission shaft 7, a housing 9, a bearing 8, etc., the stator 1 forming a stationary part of the electric motor, which is composed of a stator lamination stack 2, on which windings 3 of the electric motor are arranged. The motor shaft sensor 100 based on the graphene coating is arranged at the end part of the stator 1 of the motor, namely the end part close to the side of the motor transmission shaft 7 outputting power; the graphene plating layer 11 is plated on the outer surface of the motor transmission shaft 7; the probe also comprises a sleeve 15, electrode plates 16 and the like, the head end of the rigid metal detector 13 is in contact with the graphene coating 11, the cross section of the rigid metal detector 13 can be rectangular, the built-in piezoelectric crystal 14 can be a piezoelectric crystal piece, the sleeve 15 is provided with an inner hole, the tail end of the rigid metal detector 13 extends into the inner hole of the sleeve 15, the left side surface and the right side surface of the rigid metal detector 13 are respectively in close contact connection with the built-in piezoelectric crystal 14, the two electrode plates 16 are respectively arranged on the side surfaces of the built-in piezoelectric crystal 14 and are in close contact connection, and the two electrode plates 16 are mutually; a binding post 17 can be arranged on the end face of the tail end of the rigid metal detector 13, the conducting wires of the two electrode plates 16 are communicated with the binding post 17, the output circuit 12 can be arranged outside the motor shell, and the binding post 17 is connected with the conducting wires to be communicated with the output circuit 12; the probe is fixed to the support 18 and is fixed to the end of the stator 1 of the motor through a mounting hole in the support 18.

When the motor transmission shaft 7 rotates, the rigid metal detector 13 detects that the graphene coating 11 on the motor transmission shaft generates periodic displacement, and since the rigid metal detector is fixed, the graphene coating 11 generates periodic pressure on the rigid metal detector, and the pressure is transmitted to the built-in piezoelectric crystal 14, so that the built-in piezoelectric crystal 14 is driven to generate periodic charge signals, wherein the signals can contain motion information on the motor transmission shaft; the output circuit 12 receives the charge signal, converts the charge signal into an electrical signal and outputs the electrical signal, and sends the electrical signal to a computer through a communication cable or a communication module, and the computer calculates the rotating speed of the motor according to the change frequency of the received signal. Therefore, the motor shaft sensor based on the graphene coating has the advantages of simple structure, small volume, light weight, high precision and reliable performance, and can be suitable for high-precision motor tests, particularly for micro-special motor tests.

The axial length of the graphene plating layer 11 is set to 1 to 10 mm. The length of the output shaft of the motor is selected according to the length of the output shaft of the motor, and in a special case, for a medium-sized motor with the length of the output end of a transmission shaft of the motor being 10cm, the shaft diameter being 5cm, the power being 10kW and the rotating speed being lower than 1500r/min, the axial length of the graphene coating 11 can be set to be 1 mm.

In order to make the graphene plating layer have good hardness and wear resistance, the number of layers of the graphene plating layer is preferably set to 10 or more.

In order to measure the performance parameters of the motor during operation with high precision and to cause the metal detector to generate periodic displacement so as to drive the built-in piezoelectric crystal to generate periodic signals, the cross-sectional shape of the graphene plating layer 11 is preferably a sawtooth 19, and the sawtooth 19 is preferably a continuously arranged congruent triangle and is circumferentially distributed. The surface of a transmission shaft of the motor can be firstly processed to form a sawtooth shape, and then the processed surface of the transmission shaft is plated with a graphene coating, so that the uniformity of the coating can be ensured. In a specific example, for the above-mentioned medium-sized motor, the teeth 19 may be shaped as an isosceles triangle having two sides with a length of 0.2 μm, an included angle of 70 degrees between the two sides, and a pitch of 1.9058 μm.

The rigid metal detector is made of a rigid metal material. The rigid metal detector can be made of aluminum alloy materials, and the aluminum alloy has the advantages of light weight, good conductivity, good mechanical property, good processability and the like.

In order to ensure that the rigid metal detector is always in contact with the graphene coating and accurately conduct the change of motion information on the transmission shaft, it is preferable that one end of the rigid metal detector in contact with the graphene coating is a cone 20, the tip of the cone 20 is inserted into the gap of the saw teeth 19, and the side surface of the cone 20 is in contact with the side surface of the saw teeth. The geometry of the gap of the saw teeth 19 may be set to be slightly larger than the outer dimensions of the cone 20 to ensure that the cone 20 always remains in contact with the sides of the saw teeth 19.

The output circuit 12 includes electronic circuitry for a/D conversion and signal output functions, and is used for output as an electrical signal for the entire sensor. The output circuit 12 may be a general-purpose electronic circuit having a/D conversion and signal output functions, and may convert the received charge signal into a digital signal through an a/D converter, and output the digital signal to a computer through a communication cable or a communication module.

The motor shaft sensor based on the graphene coating further comprises a computer, and the computer is connected with the output circuit; and the computer is used for receiving the output electric signal of the output circuit and calculating the rotating speed of the motor.

The output circuit sends the digital quantity electric signal to the computer, and the computer can calculate the rotating speed of the motor according to the change frequency of the received signal, and the error of the rotating speed can not exceed one millionth. The calculation process is as follows:

for a medium-sized motor with the output end length of the motor transmission shaft being 10cm, the shaft diameter being 5cm, the power being 10kW and the rotating speed being lower than 1500r/min, the axial length of the graphene coating can be set to be 1 mm; for the medium-sized motor, the saw teeth can be shaped as an isosceles triangle, the two sides are 0.2 microns long, the included angle between the two sides is 70 degrees, and the tooth tip distance is 1.9058 microns.

As shown in fig. 5, the square wave period is about 0.39 μ s calculated by averaging a plurality of periods, and the linear speed of the output of the corresponding motor is 1.9058/0.39-4.887 m/s, which can be converted to 1440r/min of the rotation speed of the motor if the radius of the transmission shaft is 3.2 cm.

If the radius of the transmission shaft is 3.2cm, the tooth tip spacing of the sawteeth is 1.9058 microns, so that the tooth tip included angle of every two sawteeth can be calculated, and when the transmission shaft rotates, the computer can calculate the angular displacement of the rotor in real time according to the change frequency of the received signals, so that the real-time position of the rotor is judged.

In addition, under the condition that the power of the motor is fixed, the torque and the rotating speed of the motor are in inverse proportion relation, the higher the rotating speed is, the smaller the torque is, and the larger the torque is, the vice versa, so that the computer can calculate the output torque of the motor according to the rotating speed of the motor.

The graphene coating on the outer surface of the motor transmission shaft can be prepared by the following method:

step 1, respectively cleaning the surface of a transmission shaft of a motor for 5-15 minutes by sequentially using 0.5-2mol/L acetone and 0.5-2mol/L hydrochloric acid at room temperature;

step 2, washing the substrate with deionized water again and then drying the substrate;

step 3, soaking the motor transmission shaft in 3-Aminopropyltriethoxysilane (APTES) aqueous solution for 1-3 hours;

step 4, cleaning a motor transmission shaft by using ethanol, and drying in an environment with the temperature of 50-55 ℃;

step 5, immersing the motor transmission shaft processed in the step 4 into 0.01-0.1mg/mL graphene aqueous solution, and controlling the temperature to be 50-55 ℃; when the graphene can be observed to be successfully plated on the motor transmission shaft, the motor transmission shaft is moved out; after the film is naturally dried at room temperature, the whole film coating process is finished.

The preparation process of the graphene coating on the outer surface of the transmission shaft of the motor is as follows:

firstly, the surface of the motor transmission shaft is treated by a chemical method, so that the graphene oxide 3 can be more easily and uniformly adsorbed on the surface of the motor transmission shaft, and more importantly, the measurement sensitivity of the sensor can be improved, namely, the surface of the motor transmission shaft is respectively cleaned by acetone and hydrochloric acid (the concentration is 1mol/L) at room temperature for 10 minutes, and the other purpose is to remove organic pollutants on the surface of the motor transmission shaft. Then, the substrate was washed with deionized water again and dried.

In order to increase the number of silanol groups on the surface of the motor drive shaft, it was immersed in a NaOH (1mol/L) solution for 1 hour; subsequently, the motor shaft was immersed in a solution of 3-Aminopropyltriethoxysilane (APTES) for 2 hours, and the 3-Aminopropyltriethoxysilane (APTES) interacted with the hydroxyl groups on the silica surface of the motor shaft, thereby forming a Si-O-Si covalent bond. And cleaning the transmission shaft of the motor by using ethanol, and drying for 30 minutes in an environment with the temperature of 50 ℃ after cleaning, wherein the environment with the temperature of 50 ℃ is realized by a constant temperature and humidity box. Finally, the treated motor drive shaft was immersed in 0.06mg/mL graphene water solution, with the temperature controlled at 50 ℃. After successful graphene plating on the motor drive shaft was observed, the motor drive shaft was removed from the aqueous graphene solution. The whole film coating process is finished after the film is naturally dried for 12 hours at room temperature.

The main working principle of the motor shaft sensor based on the graphene coating is as follows:

graphene has better hardness and can be finely processed into a graphene coating with a zigzag structure; the rigid metal detector is fixed on the stator of the motor, and the conical tip of the rigid metal detector is inserted into the gap of the sawteeth; when the motor transmission shaft rotates, the rigid metal detector detects that the graphene coating on the motor transmission shaft generates periodic displacement, and because the rigid metal detector is fixed, the sawteeth generate periodic pressure on the rigid metal detector, and the pressure is transmitted to the built-in piezoelectric crystal to drive the built-in piezoelectric crystal to generate periodic charge signals, wherein the signals can contain motion information on the motor transmission shaft; the output circuit receives the charge signal, converts the charge signal into a digital signal through the A/D converter and outputs the digital signal, and sends the digital signal to the computer through the communication cable or the communication module, and the computer calculates the rotating speed and the torque of the motor according to the change frequency of the received signal and can judge the real-time position of the rotor.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.