Bearing retainer state monitoring device

Abstract

The invention discloses a bearing retainer state monitoring device. A stress detection and rotating speed detection circuit for a bearing retainer is configured in the device, and the circuit comprises a main control chip circuit which collects and processes various sensor data in real time through the high-performance processing capability of main control chip integration; the power supply provides stable power supply for each module; the angle and rotating speed detection circuit is used for measuring the angle and rotating speed data of the retainer by using an MPU6050 sensor, and is communicated with the main control chip through an I2C (Inter-Integrated Circuit) interface; the stress detection circuit is used for detecting a stress signal of the bearing retainer through a strain gauge; and the storage circuit is used for storing the collected data. Through cooperative work of all the modules, real-time and high-precision detection of the stress and the rotating speed of the bearing retainer is achieved, and reliable data support is provided for bearing state monitoring.

Description

Technical Field

[0001] The invention relates to the technical field of bearing state monitoring, and in particular to a stress detection and rotation speed detection circuit for a bearing retainer and a bearing retainer state monitoring device. Background Art

[0002] In mechanical equipment, the operating state of the bearing cage is crucial, and its stability and reliability directly affect the overall performance and service life of the equipment. As one of the indispensable components of rolling bearings, the cage's structural design and performance will directly affect the stability and efficiency of the entire bearing and even the entire bearing transmission system. Especially under high-speed conditions, the reliability and stability of the cage become key points. For example, in aviation turbojet engines, the vibration and fatigue fracture of the cage are fatal problems affecting flight safety. Many domestic and foreign air parking accidents are caused by the fatigue fracture of the cage. Under high-speed conditions, the internal components of the bearing are unevenly loaded, and various collisions are frequent. The main reason for the failure of the bearing is this dynamic instability. The dynamic instability of the cage has a huge impact on the overall stability of the bearing and is of great significance. However, the existing stress and speed detection devices mainly have problems such as low detection accuracy, slow response speed, insufficient data processing capability, and low system integration, which are difficult to meet the high-precision detection requirements under complex conditions. Therefore, there is an urgent need for a stress and speed detection device with high precision, high response speed, strong data processing capability and high system integration to ensure the safe operation of mechanical equipment and effective fault warning. Summary of the invention

[0003] In view of the deficiencies of the above-mentioned prior art, the present invention aims to propose a bearing cage state monitoring device based on stress detection and speed detection circuits. The present invention achieves high-precision and real-time monitoring of the bearing cage operating state by testing the angle, speed and stress of the bearing cage, thereby solving the problems of low detection accuracy, slow response speed, insufficient data processing capability and low system integration in the prior art.

[0004] The present invention provides a stress detection and speed detection circuit for a bearing cage, which is configured in a bearing cage state monitoring device and includes:

[0005] A main control chip circuit, which includes a main control chip, is used to collect and process a variety of sensor data in real time;

[0006] Angle and speed detection circuit, which includes an MPU6050 sensor and an I2C interface. The MPU6050 sensor measures the angle and speed data of the bearing cage and communicates with the main control chip through the I2C interface;

[0007] A stress detection circuit, comprising a first strain gauge, a second strain gauge, a voltage detection circuit and an amplifier circuit; the voltage detection circuit is constructed around the first strain gauge and the second strain gauge, the first strain gauge is located at the side of the cage beam of the bearing cage to be detected, which is used to separate adjacent pockets and contacts the bearing roller, and is deformed by stress, and the resistance value changes with the deformation, and the stress at the location of the first strain gauge is calculated according to the voltage change caused by the resistance change of the first strain gauge due to the stress; the first strain gauge is in a branch of the voltage detection circuit, the second strain gauge is set at a symmetrical position, and the second strain gauge is not subject to stress; the amplifier circuit amplifies the voltage at the output end of the voltage detection circuit;

[0008] A storage circuit, used to store data collected by the signal angle and speed detection circuit and the stress detection circuit;

[0009] The power supply is used to supply power to the main control chip circuit, the angle and speed detection circuit, the stress detection circuit, the amplifier circuit and the storage circuit.

[0010] In the present invention, the main control chip is an STM32L431 chip, the amplifier circuit takes the HX711 chip as the core, the power supply uses a 3V button battery, and the storage circuit includes a flash memory chip.

[0011] In the present invention, the angle and rotation speed detection circuit includes an MPU6050 sensor.

[0012] In the present invention, the axis of the strain gauge of the stress detection circuit is parallel to the axis of the cage beam of the bearing cage to be detected and used to separate adjacent pockets.

[0013] In the present invention, the voltage detection circuit in the stress detection circuit is a strain bridge structure, the voltage is provided by the input port Vin, and the circuit is divided into two parallel branches: the first branch includes a resistor R1, a second strain gauge R4 and a resistor R6 in series, and the second branch includes a resistor R2, a first strain gauge R and a resistor R7 in series, and the two branches are grounded through a resistor R8 respectively. Resistors R3 and R5 are connected in parallel at both ends of the two strain gauges to balance the strain bridge; output port E1 and output port E2 are used to detect the voltage at both ends of resistor R5, and output port E3 is used to detect the voltage at this point to assist calculation, thereby realizing the detection of the voltage change at both ends of resistor R5.

[0014] Preferably, the resistors R1 - R3 and R6 - R8 are equal-value resistors with known resistance values.

[0015] In the present invention, the working process of the stress detection circuit includes:

[0016] S1, voltage change of output ports E1 and E2 obtained based on resistance change of strain gauge in voltage detection circuit;

[0017] S2, inputs the output ports E1 and E2 into the amplifier circuit, amplifies the tiny voltage change signal several times, and obtains the amplified voltage difference between the output ports E1 and E2;

[0018] S3, according to the resistance change data of the strain gauge, the initial resistance, the proportional constant, and the amplified voltage difference between the output ports E1 and E2, the resistance value of the strain gauge during detection is calculated according to the circuit, and finally the stress at the target position where the strain gauge is located is obtained.

[0019] The present invention also provides a bearing retainer state monitoring device, which includes the above-mentioned stress detection and speed detection circuit for the bearing retainer, and the device also includes a shell; the shell has a accommodating space, and the circuit board of the stress detection and speed detection circuit is arranged in the accommodating space, wherein the accommodating space is also equipped with a strain gauge that can extend out of the shell, and a power control switch connected to the power supply and extending outside the shell; and the axis of the strain gauge is parallel to the axis of the retainer beam of the bearing retainer being detected to separate adjacent pockets.

[0020] In the present invention, an adsorption assembly is arranged in the accommodating space, and the adsorption assembly includes a push rod which can move vertically relative to the shell, and an adsorption plate at the end of the push rod. An elastic device is arranged between the push rod and the shell. When the push rod is forced to move along the horizontal direction of the shell, the adsorption plate extends or retracts from the accommodating space; when the adsorption plate extends, the shell is fixed on the bearing retainer to be detected, and when the adsorption plate retracts, the fixation between the shell and the monitored bearing retainer is released.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention adopts STM32L431 as the main control chip, and through its integrated high-performance processing capability, it can collect and process various sensor data in real time; the angle and speed detection circuit uses the MPU6050 sensor to communicate with the main control chip through the I2C interface, thereby realizing high-precision and real-time monitoring of the angle and speed of the bearing retainer; the stress detection circuit detects the stress signal of the bearing retainer through the strain gauge, and converts the resistance change of the strain gauge into a voltage change signal through the voltage detection circuit; the amplifier circuit amplifies the voltage change signal and transmits it to the main control chip circuit, thereby ensuring the accurate reading of the stress signal and realizing high-precision and real-time monitoring of the stress of the bearing retainer.

[0023] (2) The STM32L431 main control chip of the present invention has low power consumption characteristics, so that the entire device can work stably for a long time and is suitable for various complex working environments.

[0024] (3) The storage circuit of the present invention includes a flash memory chip, which can store the collected stress and speed data for a long time for subsequent analysis. This design not only improves the storage capacity of the data, but also enhances the security and traceability of the data, and facilitates the long-term storage and subsequent processing of the data.

[0025] (4) The stress and speed detection circuits are configured inside the housing, providing good physical protection and electromagnetic shielding, further improving the reliability and stability of the detection.

[0026] (5) The design structure of the present invention is compact and each module is highly integrated. It is suitable for the status monitoring and fault warning system of mechanical equipment. By storing the collected stress and speed data in real time, maintenance personnel can quickly read the stored data to understand the equipment status in time and locate the fault quickly, thus avoiding long-term equipment downtime and significantly improving the safety and efficiency of equipment operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 The present invention is a circuit structure diagram for stress detection and speed detection of a bearing retainer.

[0029] Figure 2 This is the overall detection circuit diagram.

[0030] Figure 3 The flowchart of the stress detection method of the stress detection circuit according to the embodiment of the present disclosure is schematically shown.

[0031] Figure 4 is a circuit diagram of a voltage detection circuit according to an embodiment of the present disclosure.

[0032] Figure 5 It is the equivalent circuit diagram of the voltage detection circuit.

[0033] Figure 6 It is the overall schematic diagram of the bearing cage condition monitoring device.

[0034] Figure 7 It is a cross-sectional schematic diagram of a bearing cage condition monitoring device. DETAILED DESCRIPTION

[0035] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] In order to achieve real-time high-precision, high-response speed and high-system integration stress and speed detection of bearing cages, such as Figure 1-2 As shown, the present invention proposes a stress detection and speed detection circuit for a bearing cage, which is configured in a bearing cage state monitoring device. The stress detection and speed detection circuit of the bearing cage includes:

[0037] Power supply: Each detection circuit is powered by a 3V button battery to ensure long-term, low-power operation;

[0038] Main control chip circuit: including STM32L431 chip U1, using its high-performance processing capability to process and control multiple signal detection circuits; the multiple signal detection circuits are specifically: angle and speed detection circuit and pressure detection circuit; the strain gauge of the pressure detection circuit is arranged at the key part of the cage to detect the stress change during operation;

[0039] Angle and speed detection circuit: it includes an MPU6050 sensor U2; the SDA pin of the MPU6050 sensor U2 is connected to the PB7 pin of the main control chip circuit, and the SCL pin is connected to the PB6 pin of the main control chip circuit for I2C communication; the SDA and SCL pins of the MPU6050 sensor U2 are pulled up to VCC through the third resistor R3 and the fourth resistor R4 respectively, and filtered through the ninth capacitor C9 to reduce noise interference.

[0040] Pressure detection circuit: It includes a first strain gauge R, a second strain gauge R4, a voltage detection circuit and an amplifier circuit, wherein the first strain gauge R is located at the side of the bearing cage where the cage beam that separates adjacent pockets contacts the roller and is deformed by stress, and the resistance of the first strain gauge R changes with the deformation; the first strain gauge R is located in a branch of the voltage detection circuit, and a second strain gauge R4 of the same model that is not stressed is symmetrically located thereon to reduce the influence of temperature drift, and the others are all composed of fixed-value resistors with known and equal resistance values, and the voltage detection circuit also includes input ports Vin and GND and output ports E1, E2 and E3;

[0041] The present invention selects the strain test position at the side where the cage beam of the bearing cage, which is used to separate adjacent pockets, contacts the roller. This is mainly because the finite element analysis results support that this position is a stress concentration area, which directly bears the load and friction of the roller and is prone to fatigue and wear. Measuring the strain here can truly reflect the stress state of the bearing, which is convenient for early detection of potential problems. At the same time, this position is perpendicular to the force exerted on the cage by the bearing roller, and can maximize the accuracy of measuring the stress on the cage.

[0042] Figure 3 The flowchart of the stress detection method based on the voltage detection circuit of the embodiment of the present disclosure is schematically shown, and the specific process is as follows:

[0043] Operation S310, based on the change of the resistance of the strain gauge in the overall circuit, the voltage change of the output ports E1 and E2 is obtained. Due to the stress at the target position, the initial resistance of the first strain gauge changes, resulting in a corresponding change in the voltage of the output ports E1 and E2.

[0044] Operation S320, the voltage signals of the output port E1 and the output port E2 are input into the amplifier circuit, and the tiny voltage signal is amplified by 128 times to obtain the voltage difference between the output port E1 and the output port E2 after amplification. By signal amplification, it is ensured that the subsequent circuit can accurately process and analyze the voltage signal, thereby improving the measurement accuracy.

[0045] In operation S330, the resistance value of the strain gauge during detection is calculated based on the resistance change data, initial resistance value, proportional constant of the strain gauge, and the voltage difference between the output port E1 and the output port E2 after amplification, and finally the stress at the target position where the strain gauge is located is calculated. In this embodiment, there is a linear relationship between the resistance change, initial resistance value and proportional constant of the strain gauge. Therefore, when these parameters are known, the stress value at the target position can be obtained by calculation.

[0046] Figure 4 A circuit diagram of a voltage detection circuit is schematically shown.

[0047] Voltage detection circuit: it includes a first strain gauge R and a second strain gauge R4, the first strain gauge R is connected in series between the resistors R2 and R7 in the second branch, and is used to detect stress changes, and the second strain gauge R4 is connected in series between the resistors R1 and R6 in the first branch, and is used to reduce the measurement error caused by temperature drift; the resistor R3 and the resistor R5 are connected in parallel, respectively connected at both ends of the first strain gauge R and the second strain gauge R4, and are used to balance the strain bridge structure; the input terminal Vin is used to power the circuit, and the two branches are grounded through the resistor R8, the output port E1 and the output port E2 are used to detect the voltage at both ends of the resistor R5, and the output port E3 is used to detect the voltage at this point to assist calculation, thereby realizing the detection of voltage changes.

[0048] like Figure 4 As shown, the second strain gauge R4 is in an equivalent position to the first strain gauge R and is at the same temperature. This circuit design can reduce the measurement error caused by temperature drift and increase the stress measurement accuracy. The other resistors R1~R3 ​​and R5~R8 are fixed resistors with known and equal resistance values. The circuit selects a 3.3V power supply to supply power separately and shares the ground with the main control chip circuit. The voltage difference between the E1 and E2 terminals is the output voltage E0 of the voltage detection circuit, that is, the voltage required to measure the calculated resistance. According to the embodiment of the present disclosure, since the initial resistance of the strain gauge changes with the deformation caused by the stress at the target position, resistance change data ΔR will be generated, causing the voltage E0 output by the circuit to change, and then the resistance R of the strain gauge can be calculated by the voltage E0 output by the circuit, and ΔR can be obtained.

[0049] According to the embodiments of the present disclosure and the properties of the voltage detection circuit, the voltage measurement circuit can be equivalent to Figure 5 , so according to Kirchhoff's law for Figure 4 The circuit can be listed as the following system of equations:

[0050]

[0051] Where i1 is Figure 4 The current in the branch where the strain gauge R is located in the circuit, i2 is Figure 4 The current in the branch where the strain gauge R4 is located in the circuit, i3 is Figure 4 The current in the branch where resistor R5 is located in the circuit, i 总 for Figure 4 The total current of the circuit, E0 is the voltage difference between output port E1 and output port E2, E3 is the voltage of output port E3, Figure 4 The resistance values ​​of resistors R1~R3 ​​and R5~R8 in the circuit are equal to R ° .

[0052] Therefore, according to Kirchhoff's law, Figure 5 The circuit can be listed as follows:

[0053] i1(2R′+R)=3.3-i 总 (2R′+R°) (5)

[0054]

[0055] Where i1 is Figure 5 The current in the branch where the strain gauge R is located in the equivalent circuit is Figure 4 In i1 is equal, i 总 for Figure 5 The total current of the equivalent circuit is Figure 4 in i 总Equal, R′ is the equivalent value of the resistance R° when the △-type circuit is converted to a Y-type circuit.

[0056] Combine equations (1) to (6) to solve the value of strain gauge R

[0057]

[0058] The resistance change of the strain gauge is

[0059] ΔR=R-R0 (8)

[0060] Where R0 is the initial resistance of the strain gauge R.

[0061] According to an embodiment of the present disclosure, the stress at the target position is obtained based on the resistance change data ΔR of the strain gauge, the initial resistance R0 and the proportional constant Ks, including: based on the proportional constant, processing the ratio of the resistance change data to the initial resistance to obtain the stress at the target position where the strain gauge is located.

[0062] According to the embodiments of the present disclosure, the resistance change data, initial resistance and proportional constant of the strain gauge are linear as shown in the following formula (9).

[0063]

[0064] Where Ks is the proportionality constant and ε is the stress at the target position.

[0065] According to the embodiments of the present disclosure, combined with the above formulas (7) to (9), the mechanical elongation or shortening of the strain gauge under stress can be converted into resistance change. Based on the change in the resistance of the strain gauge, the stress at the target position can be calculated according to the following formula (10):

[0066]

[0067] In the above, the bearing retainer is detected based on the stress detection circuit to obtain the resistance change data of the first strain gauge R, including: in response to the change of the initial resistance of the first strain gauge R under the stress, the output voltage of the voltage detection circuit is obtained; according to the output voltage, the resistance change data is obtained. Further, according to the resistance change data and the initial resistance of the first strain gauge R, the stress ε at the target position is obtained, including: based on the proportional constant Ks, the resistance change data R0 and the initial resistance ΔR are processed to obtain the stress ε at the target position where the strain gauge is located.

[0068] In the stress detection circuit of the present invention, since the voltage change generated by the first strain gauge R when subjected to stress is extremely small, it is difficult to directly and accurately measure it. Therefore, the output ports E1 and E2 of the voltage detection circuit are connected to the amplifier circuit, which is used to amplify the voltage signal converted from the stress signal and transmit it to the main control chip circuit. The voltage signal can be amplified 128 times to obtain the amplified voltage at the E1 and E2 terminals; the amplifier circuit includes:

[0069] HX711 amplifier module U3; the VSUP pin of the HX711 amplifier module U3 is connected to the power supply VCC to provide the power supply voltage; the AVDD pin of the HX711 amplifier module U3 is connected to the ground through the C10 capacitor (1uF) to stabilize the power supply voltage; the AGND pin of the HX711 amplifier module U3 is connected to the ground; the INNA and INPA pins of the HX711 amplifier module U3 are respectively connected to the output ports E1 and E2 of the voltage detection circuit to collect voltage signals; the INNB and INPB pins of the HX711 amplifier module U3 are respectively connected to the ground and the output port E3 of the voltage detection circuit. Used to collect voltage signals; the VFB pin of the HX711 amplifier module U3 is connected to the VIN end of the voltage detection circuit through the fifth resistor R5 for feedback signal; the VBG pin of the HX711 amplifier module U3 is connected to the ground through the twelfth capacitor C12 for stabilizing the reference voltage; the PD_SCK pin and DOUT pin of the HX711 amplifier module U3 are connected to the main control chip circuit through HX711_SCK and HX711_DT respectively for data communication; the BASE pin of the HX711 amplifier module U3 is connected to VFB through the first transistor Q1 to control the reference voltage of the amplifier.

[0070] The amplifier circuit not only amplifies the tiny signal, but also improves the signal-to-noise ratio by suppressing noise and interference, ensuring the accuracy and reliability of the measurement. Through this amplification process, the main control chip can accurately read and process the voltage data to ensure the accuracy of the calculated stress data.

[0071] Storage circuit: including flash memory chip, used for long-term storage of collected stress and rotation speed data, so as to facilitate subsequent analysis of the stored collected data.

[0072] The present invention stores the collected stress and rotation speed data in real time, so that maintenance personnel can understand the equipment status in time by quickly reading the stored data.

[0073] The present invention also provides a bearing cage state monitoring device. Figure 6 and Figure 7 As shown, the bearing retainer state monitoring device includes a housing 52, and the housing 52 has a receiving space, and the receiving space has a circuit board 63 of the stress detection circuit and the rotation speed detection circuit built in the above-mentioned circuit board.

[0074] The housing 52 is provided with a power switch 53, a TYPE-C port 54, and a strain gauge 55 connected to the internal circuit of the housing. The power switch 53 is used to control the switch of the detection circuit. The TYPE-C port 54 is connected to the serial port of the main control chip and is a data communication interface.

[0075] In a preferred embodiment, in order to further improve the convenience of users during debugging and testing, an adsorption component is added in the accommodation space, which includes a push rod 61 that can move vertically relative to the shell 52, one end of the push rod 61 is connected to the inner wall of the accommodation space through an elastic device 62, and the other end of the push rod 61 is installed with an adsorption plate 51. When the user presses the position of the shell 52 corresponding to the push rod 61, the push rod 61 is subjected to pressure in the vertical direction, and the adsorption plate 51 will be synchronously extended out of the accommodation space and fit with the adsorbed object to achieve the fixation of the shell 52; when the user releases the shell 52 and the pressure is released, the adsorption plate 51 retracts into the accommodation space under the action of the elastic device 62, and the elastic device 62 resets the push rod 61. Through the adsorption component, the bearing cage state monitoring device can be conveniently fixed on the cage beam of the bearing cage used to separate adjacent pockets, which is easy to install, avoids damage to the cage structure, and effectively improves the accuracy and efficiency of testing or detection.

[0076] In a preferred embodiment, the adsorption assembly is located at the left side of the accommodation space and is arranged perpendicularly to the axis of the housing 52. This design not only ensures the horizontal state of the housing 52 when it is fixed, but also makes full use of the internal space of the accommodation space.

[0077] In a preferred embodiment, in order to facilitate the release of the adsorption effect of the adsorption disk 51, a protrusion 56 is provided on the side of the adsorption disk 51 away from the push rod 61, and the protrusion 56 extends in a direction away from the adsorption disk 51. When the fixing of the shell 52 needs to be released, the user can pull the protrusion 56 to allow external air to enter between the adsorption disk 51 and the adsorbed object, thereby separating the adsorption disk 51 from the adsorbed object and releasing the fixing of the shell 52.

[0078] As described above, the present invention monitors the operating status of the bearing retainer by testing its angle, rotation speed and stress. Angle, rotation speed and stress detection are closely related to fault warning. By monitoring the angle change of the bearing retainer, it is possible to promptly detect whether it is tilted, offset or deformed, which may be early signs of a fault. Speed ​​detection can identify abnormal rotation speeds, such as sudden acceleration, deceleration or unstable rotation, indicating potential mechanical problems. Stress detection directly reflects the change in the mechanical load borne by the retainer, and excessive stress may cause material fatigue or damage. Comprehensive analysis of the changing trends of these parameters can identify abnormal situations early, provide early warning of faults, prevent the occurrence of serious faults, and ensure the safe operation of the equipment.

[0079] It should be noted that, in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the present invention, unless otherwise clearly specified and limited, the terms "connected", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0080] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A stress detection and speed detection circuit for a bearing cage, configured in a bearing cage state monitoring device, characterized in that: include: A main control chip circuit, which includes a main control chip, is used to collect and process a variety of sensor data in real time; Angle and speed detection circuit, which includes an MPU6050 sensor and an I2C interface. The MPU6050 sensor measures the angle and speed data of the bearing cage and communicates with the main control chip through the I2C interface; A stress detection circuit, comprising a first strain gauge, a second strain gauge, a voltage detection circuit and an amplifier circuit; the voltage detection circuit is constructed around the first strain gauge and the second strain gauge, the first strain gauge is located at the side of the cage beam of the bearing cage to be detected, which is used to separate adjacent pockets and contacts the bearing roller, and is deformed by stress, and the resistance value changes with the deformation, and the stress at the location of the first strain gauge is calculated according to the voltage change caused by the resistance change of the first strain gauge due to the stress; the first strain gauge is in a branch of the voltage detection circuit, the second strain gauge is set at a symmetrical position, and the second strain gauge is not subject to stress; the amplifier circuit amplifies the voltage at the output end of the voltage detection circuit; A storage circuit, used to store data collected by the signal angle and speed detection circuit and the stress detection circuit; The power supply is used to supply power to the main control chip circuit, the angle and speed detection circuit, the stress detection circuit, the amplifier circuit and the storage circuit.

2. The stress monitoring and speed detection circuit according to claim 1, characterized in that: The main control chip is the STM32L431 chip, the amplifier circuit is based on the HX711 chip, the storage circuit includes a flash memory chip, and the power supply uses a 3V button battery.

3. The stress detection and speed detection circuit according to claim 1, characterized in that: The angle and speed detection circuit includes the MPU6050 sensor.

4. The stress detection and speed detection circuit according to claim 1, characterized in that: The axis of the strain gauge of the stress detection circuit is parallel to the axis of the cage beam of the detected bearing cage used to separate adjacent pockets.

5. The stress detection and speed detection circuit according to claim 1, characterized in that: The voltage detection circuit in the stress detection circuit is a strain bridge structure, and the voltage is provided by the input port Vin. The circuit is divided into two parallel branches: the first branch includes a resistor R1, a second strain gauge R4 and a resistor R6 in series, and the second branch includes a resistor R2, a first strain gauge R and a resistor R7 in series. The two branches are grounded through a resistor R8. Resistors R3 and R5 are connected in parallel at both ends of the two strain gauges to balance the strain bridge; output ports E1 and E2 are used to detect the voltage at both ends of resistor R5, and output port E3 is used to detect the voltage at this point to assist in calculation, thereby realizing the detection of the voltage change at both ends of resistor R5.

6. The stress detection and rotation speed detection circuit according to claim 5, characterized in that: The working process of the stress detection circuit includes: S1, voltage change of output ports E1 and E2 obtained based on resistance change of strain gauge in voltage detection circuit; S2, inputs the output ports E1 and E2 into the amplifier circuit, amplifies the tiny voltage change signal several times, and obtains the amplified voltage difference between the output ports E1 and E2; S3, according to the resistance change data of the strain gauge, the initial resistance, the proportional constant, and the amplified voltage difference between the output ports E1 and E2, the resistance value of the strain gauge during detection is calculated according to the circuit, and finally the stress at the target position where the strain gauge is located is obtained.

7. A bearing cage state monitoring device, comprising a stress detection and speed detection circuit for a bearing cage according to any one of claims 1 to 6, characterized in that: The device also includes a shell; the shell has a accommodating space, and the circuit board of the stress detection and speed detection circuit is arranged in the accommodating space, wherein the accommodating space is also installed with a strain gauge that can extend out of the shell, and a power control switch connected to the power supply and extending out of the shell; and the axis of the strain gauge is parallel to the axis of the cage beam of the bearing cage to be detected for separating adjacent pockets.

8. The bearing retainer state monitoring device according to claim 7, characterized in that: An adsorption assembly is arranged in the accommodating space, and the adsorption assembly includes a push rod which can move vertically relative to the shell, and an adsorption plate at the end of the push rod. An elastic device is arranged between the push rod and the shell. When the push rod is forced to move along the horizontal direction of the shell, the adsorption plate extends or retracts from the accommodating space; when the adsorption plate extends, the shell is fixed on the bearing retainer to be detected, and when the adsorption plate retracts, the fixation between the shell and the monitored bearing retainer is released.

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