A frictional electric wheel speed sensor based on a magnetic field modulation mechanism

Abstract

The application discloses a triboelectric wheel speed sensor based on a magnetic field modulation mechanism and belongs to the technical field of speed measurement and sensing. The sensor comprises a mechanical sensing unit and a signal processing unit; the mechanical sensing unit adopts a coaxial nesting structure of a low-speed rotor, a fixing device and a high-speed rotor, utilizes a magnetic gear mechanism to convert low-speed rotation into reverse high-speed rotation of the high-speed rotor, and further drives a friction nanometer power generation unit to generate an alternating voltage signal in direct proportion to frequency and rotation speed; the signal processing unit is used for processing the signal and calculating wheel speed and linear speed. The application combines the magnetic field modulation with the friction power generation, effectively improves the output signal frequency and signal-to-noise ratio under low-speed working conditions, has the self-powered characteristic, overcomes the defects that the traditional sensor has weak signal and relies on external power supply under low speed, and provides a high-reliability solution for wheel speed monitoring of intelligent traffic.

Description

TECHNICAL FIELD

[0001] The application relates to a frictional electric wheel speed sensor based on a magnetic field modulation mechanism and belongs to the technical field of speed measurement sensing. BACKGROUND

[0002] With the development of intelligent transportation systems, wheel speed sensors occupy a pivotal position due to their unique basicity, criticality and irreplaceability. High-precision wheel speed monitoring is crucial for detecting driving conditions, ensuring driving safety and comfort, and evaluating road usage to improve traffic flow efficiency. However, traditional rotation speed sensors, such as magneto-electric and Hall sensors, face two major bottlenecks in practical applications. Firstly, they rely on external power supply and are difficult to deploy widely in low-power, distributed Internet of Things nodes. Secondly, under low-speed rotation conditions, the output signal amplitude is low and the signal-to-noise ratio is poor, resulting in a significant decrease in wheel speed recognition reliability, which cannot meet the precise monitoring needs of intelligent transportation systems under conditions such as vehicle starting and low-speed cruising. Therefore, developing a high-reliability, self-powered wheel speed sensor suitable for low-speed scenarios has important theoretical value and engineering significance.

[0003] As a new self-powered sensing technology, a frictional nanogenerator can directly convert mechanical rotation into voltage pulse signals through triboelectricity and electrostatic induction effects. The frequency of its output signal is directly proportional to the rotation frequency of the rotating component, which makes it unique in the field of rotation speed monitoring. However, the voltage signal frequency output by conventional frictional nanogenerators at very low rotation speeds is too low and the amplitude is too weak, making it difficult for the signal to be reliably captured by subsequent circuits, limiting its application in high-precision linear speed measurement.

[0004] The introduction of the magnetic field modulation mechanism provides an effective solution to the above bottlenecks. This mechanism configures a magnetic circuit structure with a specific number of pole pairs, allowing the generation of a high-frequency alternating magnetic field inside the generator when the external rotor rotates at low speed. This effectively converts low-speed rotational mechanical energy into high-frequency, high signal-to-noise ratio voltage pulse sequences. Combining magnetic field modulation technology with frictional nanogenerators can linearly map mechanical rotation speed to voltage signal frequency. By detecting this frequency value and combining the radius parameter of the rotating body, the linear speed of its edge can be directly calculated, providing a reliable technical foundation for high-precision, self-powered linear speed measurement.

[0005] In view of the above defects, the application provides a frictional electric wheel speed sensor based on a magnetic field modulation mechanism. This sensor can directly convert the rotational mechanical energy of the wheel into high-frequency voltage pulse signals. By measuring the frequency of the output signal and combining the wheel radius, the corresponding linear speed can be calculated in real time, thereby achieving high-precision, self-powered wheel speed monitoring. SUMMARY

[0006] In order to solve the problems of weak signal, insufficient reliability and dependence on external power supply of the existing wheel speed sensor under low speed working condition, the application discloses a triboelectric wheel speed sensor based on magnetic field modulation mechanism.

[0007] The technical scheme adopted by the application is:

[0008] In order to achieve the above-mentioned purpose, the application provides a triboelectric wheel speed sensor based on magnetic field modulation mechanism, which comprises a mechanical structure and a signal processing unit.

[0009] The application provides a triboelectric wheel speed sensor based on magnetic field modulation mechanism, which efficiently converts external rotating kinetic energy into driving mechanical energy of a friction nanogenerator unit through magnetic field coupling effect, so that the friction nanogenerator unit is periodically contacted and separated and generates an alternating voltage signal. The signal is shaped by a signal conditioning circuit, and is collected and processed in real time by a built-in microprocessor based on a frequency measurement method. The frequency of the voltage pulse is accurately measured, and the corresponding rotational angular velocity and driving linear velocity are directly calculated by combining the pre-stored wheel radius parameters. The magnetic gear set based on the magnetic field modulation mechanism significantly improves the frequency and signal-to-noise ratio of the output signal under low speed conditions, so that the sensor can output stable and reliable frequency signals in a wide range from low speed to high speed, overcoming the technical bottleneck of traditional sensors in low speed monitoring. The application has compact structure and strong compatibility, and can be directly installed on rotating parts such as bicycle and automobile hubs, providing a high-precision, self-powered wheel speed monitoring solution for intelligent transportation systems.

[0010] The rotating shaft and the low speed rotor are fixed together through interference fit and rotate at the same speed. The rotating shaft and the fixed device are connected together through bearings installed on the fixed device, and the fixed device is fixed to keep it stationary. The rotating shaft and the high speed rotor are connected together through two bearings installed on the high speed rotor. After the magnetic field modulation mechanism, the high speed rotor rotates in the opposite direction at several times the speed of the low speed rotor.

[0011] The low speed rotor is composed of a low speed rotor center hole, a low speed rotor magnet installation gap and a low speed rotor magnet.

[0012] The high-speed rotor is integrated with a power generation function, a central hole is formed in the main structure, and the high-speed rotor magnet is fixed by interference fit.

[0013] The fixing device is integrated with a power generation unit stator, the main body is provided with a central hole and an iron block mounting groove, the iron block is pressed into the groove by interference fit, and the power generation unit stator adopts a design of interdigital electrodes and is attached to the inside of the fixing device main body.

[0014] The low-speed rotor, the fixing device and the high-speed rotor are axially positioned by the shaft shoulder of the rotating shaft, and together constitute an inner-to-outer three-layer nested assembly: the high-speed rotor is placed in the fixing device, and then the fixing device is nested in the low-speed rotor. This layout greatly improves the utilization rate of the radial space, thereby ensuring the compactness of the prototype structure.

[0015] The total number of the low-speed rotor magnets is P, the total number of the high-speed rotor magnets is S, and the total number of the iron blocks is 2n, wherein P, S and 2n are in an integral multiple relationship.

[0016] The signal processing unit includes a signal processing circuit and a microprocessor, wherein the signal processing unit is composed of an instrument amplifier and a hysteresis comparator.

[0017] The beneficial effects of the present application are as follows:

[0018] The present application provides a frictional electric wheel speed sensor based on a magnetic field modulation mechanism, which combines the speed multiplication effect of a magnetic gear set with the high sensitivity characteristics of a frictional nanometer generator to construct a complete self-powered speed measurement system. The sensor converts the rotational mechanical energy of the wheel into a high-frequency voltage pulse signal, and directly calculates the wheel speed and linear speed by measuring the signal frequency, fundamentally solving the problem of traditional wheel speed sensors that cannot be reliably monitored due to weak signals at low speed and relying on external power supply, providing a high-precision and high-compatibility speed sensing solution for intelligent transportation systems. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of this application. The illustrative examples, and their descriptions, serve to explain the present application, and do not constitute an improper limitation of the present application.

[0020] Figure 1 An exploded view of a frictional electric wheel speed sensor based on a magnetic field modulation mechanism is shown.

[0021] Figure 2It is a kind of low-speed rotor structure schematic diagram of triboelectric wheel speed sensor based on magnetic field modulation mechanism;

[0022] Figure 3 It is a kind of fixed device structure schematic diagram of triboelectric wheel speed sensor based on magnetic field modulation mechanism;

[0023] Figure 4 It is a kind of high-speed rotor structure schematic diagram of triboelectric wheel speed sensor based on magnetic field modulation mechanism;

[0024] Figure 5 It is a kind of rotating shaft structure schematic diagram of triboelectric wheel speed sensor based on magnetic field modulation mechanism.

[0025] In the figure: 1, low-speed rotor; 2, fixed device; 3, high-speed rotor; 4, bearing I; 5, bearing II; 6, rotating shaft; 7, bearing III; 1-1, low-speed rotor center hole; 1-2, low-speed rotor magnet installation gap; 1-3, low-speed rotor magnet; 2-1, fixed device center hole; 2-2, power generation unit stator; 2-3, ferromagnetic block installation gap; 2-4, ferromagnetic block; 3-1, high-speed rotor center hole; 3-2, high-speed rotor magnet installation gap; 3-3, high-speed rotor magnet; 3-4, power generation unit rotor; 6-1, rotating shaft shoulder I; 6-2, rotating shaft shoulder II; 6-3, rotating shaft shoulder III; 6-4 rotating shaft shoulder IV. DETAILED DESCRIPTION

[0026] The triboelectric wheel speed sensor based on magnetic field modulation mechanism comprises a low-speed rotor 1, a fixed device 2, a high-speed rotor 3, a bearing I 4, a bearing II 5, a rotating shaft 6, and a bearing III 7; the low-speed rotor 1 and the high-speed rotor 3 jointly constitute a reverse high-speed rotating mechanism, and the low-speed rotor 1, the fixed device 2, and the high-speed rotor 3 are located on the same rotating shaft 6; the low-speed rotor 1 is provided with a low-speed rotor magnet 1-3, the fixed device 2 is provided with a power generation unit stator 2-2 and a ferromagnetic block 2-4, and the high-speed rotor 3 is provided with a high-speed rotor magnet 3-3 and a power generation unit rotor 3-4; wherein the power generation unit stator 2-2 and the power generation unit rotor 3-4 constitute a friction nanometer power generation unit for generating an alternating voltage signal whose frequency is proportional to the rotating speed; a signal processing unit is connected with the power generation unit stator 2-2, used for receiving the alternating voltage signal and calculating the wheel speed and linear speed according to the frequency; the low-speed rotor magnet 1-3, the ferromagnetic block 2-4, and the high-speed rotor magnet 3-3 constitute a magnetic gear mechanism.

[0027] The low-speed rotor 1 is in interference fit with the rotating shaft 6 and rotates at the same speed; the fixing device 2 is in fit with the rotating shaft 6 through bearing III 7 and is fixed to remain stationary; the high-speed rotor 3 is in fit with the rotating shaft 6 through bearing I 4 and bearing II 5 and can rotate at high speed in the opposite direction relative to the low-speed rotor 1 under the action of the magnetic gear mechanism.

[0028] The low-speed rotor 1 comprises a low-speed rotor center hole 1-1, a low-speed rotor magnet installation gap 1-2 and a low-speed rotor magnet 1-3, wherein the low-speed rotor center hole 1-1 is a hole reserved for fit with the rotating shaft, the low-speed rotor magnet 1-3 is placed in the low-speed rotor magnet installation gap 1-2 through interference fit, and the low-speed rotor magnet 1-3 is uniformly distributed.

[0029] The fixing device 2 comprises a fixing device center hole 2-1, a power generation unit stator 2-2, a ferromagnetic block installation gap 2-3 and ferromagnetic blocks 2-4, wherein the fixing device center hole 2-1 is a hole reserved for bearing III 7, the power generation unit stator 2-2 is a interdigital electrode attached inside the fixing device 2, the ferromagnetic blocks 2-4 are uniformly distributed and placed in the ferromagnetic block installation gap 2-3 through interference fit.

[0030] The high-speed rotor 3 comprises a high-speed rotor center hole 3-1, a high-speed rotor magnet installation gap 3-2, high-speed rotor magnets 3-3 and a power generation unit rotor 3-4, wherein the high-speed rotor center hole 3-1 is a hole reserved for installation of bearing I 4 and bearing II 5, the high-speed rotor magnets 3-3 are uniformly distributed and installed in the high-speed rotor magnet installation gap 3-2 through interference fit, the power generation unit rotor 3-4 is attached to the outer surface of the high-speed rotor, and the material of the power generation unit rotor 3-4 is a high-molecular insulating film.

[0031] The rotating shaft 6 comprises a rotating shaft shoulder I 6-1, a rotating shaft shoulder II 6-2, a rotating shaft shoulder III 6-3 and a rotating shaft shoulder IV 6-4, wherein bearing I 4 and bearing II 5 are positioned through the rotating shaft shoulder I 6-1 and the rotating shaft shoulder II 6-2, bearing III 7 is positioned through the rotating shaft shoulder III 6-3, the low-speed rotor center hole 1-1 is positioned through the rotating shaft shoulder IV 6-4, and the high-speed rotor 3 is located inside the fixing device 2 through the design of the internal space, the fixing device 2 is located inside the low-speed rotor 1, forming a three-layer nested structure, which ensures the compactness of the prototype structure.

[0032] The core working principle is based on the synergistic effect of magnetic modulation and friction power generation, wherein the total number of the low-speed rotor magnets 1-3 is P, the total number of the high-speed rotor magnets 3-3 is S, and the total number of the ferromagnetic blocks 2-4 is 2n, wherein P, S and 2n are in an integer multiple relationship.

[0033] The power generation unit stator 2-2 and the power generation unit rotor 3-4 jointly constitute a friction nanogenerator in an independent layer mode.

[0034] It should be noted that the number of ferromagnetic blocks, the power generation unit pattern, etc.

[0035] Working principle:

[0036] The friction electric wheel speed sensor based on the magnetic field modulation mechanism in the application works when its rotating shaft rotates synchronously with the wheel, driving the low-speed rotor to rotate. Under the action of the magnetic field modulation mechanism, the rotating motion of the low-speed rotor is converted into the reverse high-speed rotation of the high-speed rotor, which in turn drives the power generation unit mover and the power generation unit stator to periodically contact and separate, generating an alternating voltage signal whose frequency strictly corresponds to the rotation speed. After filtering and shaping, the signal is captured by a timer to accurately measure its frequency, and then combined with the pre-stored wheel radius parameter to calculate and output the rotation angular velocity of the wheel and the linear speed of the vehicle in real time.

[0037] The friction electric wheel speed sensor based on the magnetic field modulation mechanism in the application integrates mechanical energy collection and speed sensing functions in one through a unique electromechanical conversion design. This scheme effectively realizes the direct conversion from mechanical rotation to electrical signal frequency to speed parameter, breaking through the monitoring bottleneck of traditional sensors in low-speed working conditions. Its self-powered characteristics and compact structure make it have important popularization and application value in intelligent transportation systems, providing a new technical approach for vehicle state monitoring.

Claims

1. A triboelectric wheel speed sensor based on a magnetic field modulation mechanism, characterized by, The application relates to a mechanical sensor unit and a signal processing unit, wherein the mechanical sensor unit comprises a low-speed rotor (1), a fixing device (2), a high-speed rotor (3), a bearing I (4), a bearing II (5), a rotating shaft (6) and a bearing III (7); the low-speed rotor (1) and the high-speed rotor (3) jointly constitute a reverse high-speed rotating mechanism, the low-speed rotor (1), the fixing device (2) and the high-speed rotor (3) are located on the same rotating shaft (6); the low-speed rotor (1) is provided with low-speed rotor magnets (1-3), the fixing device (2) is provided with a power generation unit stator (2-2) and a ferromagnetic block (2-4), and the high-speed rotor (3) is provided with high-speed rotor magnets (3-3) and a power generation unit rotor (3-4); wherein the low-speed rotor magnets (1-3), the ferromagnetic block (2-4) and the high-speed rotor magnets (3-3) constitute a magnetic gear mechanism; the total number of the low-speed rotor magnets (1-3) is P, the total number of the high-speed rotor magnets (3-3) is S, and the total number of the ferromagnetic block (2-4) is 2n, and P, S and 2n are integer multiples; the power generation unit stator (2-2) and the power generation unit rotor (3-4) constitute a friction nano power generation unit; under the action of a magnetic field modulation mechanism of the magnetic gear mechanism, the rotating movement of the low-speed rotor (1) is converted into the reverse high-speed rotation of the high-speed rotor (3), and then the power generation unit rotor (3-4) and the power generation unit stator (2-2) are driven to periodically contact and separate, so as to generate an alternating voltage signal with a frequency strictly corresponding to the rotating speed; the signal processing unit is connected with the power generation unit stator (2-2) and is used for receiving the alternating voltage signal and calculating the wheel speed and the linear speed according to the frequency.

2. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The low-speed rotor (1) is in interference fit with the rotating shaft (6) and rotates at the same speed; the fixing device (2) is in fit with the rotating shaft (6) through the bearing III (7) and is fixed to keep still; the high-speed rotor (3) is in fit with the rotating shaft (6) through the bearing I (4) and the bearing II (5) and can rotate reversely at high speed relative to the low-speed rotor (1) under the action of the magnetic gear mechanism.

3. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The low-speed rotor (1) comprises a low-speed rotor center hole (1-1), a low-speed rotor magnet installation gap (1-2) and low-speed rotor magnets (1-3), wherein the low-speed rotor center hole (1-1) is a hole matched with the rotating shaft and adopts interference fit, the low-speed rotor magnets (1-3) are placed in the low-speed rotor magnet installation gap (1-2) through interference fit, and the low-speed rotor magnets (1-3) are uniformly distributed.

4. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The fixing device (2) comprises a fixing device center hole (2-1), a power generation unit stator (2-2), a ferromagnetic block installation gap (2-3) and ferromagnetic blocks (2-4), wherein the fixing device center hole (2-1) is a hole reserved for the bearing III (7) and adopts interference fit, the power generation unit stator (2-2) is a interdigital electrode and is attached to the inside of the fixing device (2), the ferromagnetic blocks (2-4) are uniformly distributed and are placed in the ferromagnetic block installation gap (2-3) through interference fit.

5. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The high-speed rotor (3) comprises a high-speed rotor center hole (3-1), a high-speed rotor magnet installation gap (3-2), high-speed rotor magnets (3-3) and a power generation unit rotor (3-4), wherein the high-speed rotor center hole (3-1) is a hole reserved for the installation of bearing I (4) and bearing II (5) with interference fit, the high-speed rotor magnets (3-3) are evenly distributed and installed in the high-speed rotor magnet installation gap (3-2) through interference fit, the power generation unit rotor (3-4) is attached to the outer surface of the high-speed rotor, and the material of the power generation unit rotor (3-4) is a high-molecular insulating film.

6. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The rotating shaft (6) comprises a rotating shaft shoulder I (6-1), a rotating shaft shoulder II (6-2), a rotating shaft shoulder III (6-3) and a rotating shaft shoulder IV (6-4), wherein bearing I (4) and bearing II (5) are positioned by the rotating shaft shoulder I (6-1) and the rotating shaft shoulder II (6-2), bearing III (7) is positioned by the rotating shaft shoulder III (6-3), and the low-speed rotor center hole (1-1) is positioned by the rotating shaft shoulder IV (6-4), the high-speed rotor (3) is located inside the fixing device (2) through the design of the internal space, the fixing device (2) is located inside the low-speed rotor (1), and a three-layer nested structure is formed.

7. The frictional electric wheel speed sensor based on magnetic field modulation mechanism according to claim 1, characterized in that, The signal processing unit comprises a signal conditioning circuit and a microprocessor connected in sequence; the signal conditioning circuit is used for shaping the alternating voltage signal into a square wave pulse; and the microprocessor is used for measuring the frequency of the square wave pulse and calculating the wheel speed and the linear speed.

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