Rolling bearing and gearbox self-monitoring device

Abstract

The present application relates to a kind of rolling bearing and gearbox self-monitoring device, belong to bearing and its monitoring field.The monitoring unit is by shell, circuit board, exciter, transducer and sensor, exciter and shell are respectively mounted on inner and outer ring;Exciter is by half shaft and the magnet of uniform distribution on its circumference, the magnetic pole of adjacent magnet is respectively along the radial and axial configuration of half shaft, the magnetic pole along the radial and axial configuration magnet is respectively called radial magnet and axial magnet;Transducer is by two piezoelectric-friction cantilever vibrator, when not under external force, two friction sheets in transducer mutually adhere;Transducer is mounted on shell side wall, transducer and exciter are placed in shell interior;In work, radial and axial magnet alternately approaches-far away transducer, cantilever vibrator makes reverse reciprocating bending deformation, friction sheet reciprocating contact-separation, piezoelectric sheet stress alternately increases and decreases, transducer generates electricity by friction effect and piezoelectric effect, electric energy supplies sensor and information transmitting system and completes self-powered monitoring.

Description

Technical Field

[0001] This invention belongs to the field of bearing and its monitoring technology, specifically relating to a self-monitoring device for rolling bearings and gearboxes, which is used in engineering fields such as hydroelectric and wind turbine generators, engineering and mining machinery, which are characterized by low speed, high load, harsh environment and require real-time monitoring. Background Technology

[0002] Rolling bearings and their gearboxes are indispensable in vehicles, mining machinery, light industrial machinery, and generators, and are also the most vulnerable components in transmission systems. Because rolling bearings and gearbox gears operate under variable speed and load conditions, they are prone to failure; approximately 30% of transmission system failures are caused by the failure of bearings and other transmission components. Furthermore, repairing failed bearings and other transmission components is difficult and costly, accounting for up to 30% of total operating costs. Therefore, various real-time monitoring systems and methods for bearings and gearboxes have emerged to obtain real-time status parameters such as load, vibration, temperature, and noise, prevent equipment failures from escalating, and reduce maintenance costs. Previously, bearing and gearbox monitoring systems were mainly external, split structures, involving non-contact, indirect measurement with long distances between sensors and signal sources, resulting in large errors. In recent years, embedded monitoring systems have been combined with micro-generators based on shaft rotation, which can solve problems related to system integration and measurement accuracy to some extent; simultaneously, self-powered monitoring systems based on various micro-generators have also appeared. However, existing piezoelectric generators have certain limitations in terms of power generation capacity and reliability, and cannot yet meet the requirements for use in low-speed, especially ultra-low-speed, environments. Summary of the Invention

[0003] This invention proposes a rolling bearing and gearbox self-monitoring device, which consists of a bearing, a main shaft, and a monitoring unit. The bearing is composed of an inner ring, an outer ring, and rolling elements. The monitoring unit mainly consists of a housing, a cover, a circuit board, an actuator, a transducer, and a sensor. The inner ring of the bearing is mounted on the main shaft, and the outer ring is mounted on the inner ring via rolling elements. The rolling elements are balls, cylindrical rollers, or tapered rollers. The bearings formed using these three types of rolling elements are ball bearings, cylindrical roller bearings, and tapered roller bearings. The housing and actuator are respectively mounted on the inner ring and the outer ring, or the outer ring and the inner ring. The following describes the specific method for mounting the housing and actuator on the outer ring and the inner ring, respectively.

[0004] The exciter consists of a half-shaft and magnets evenly distributed along its circumference. The half-shaft is made of a non-ferromagnetic material, and magnets are evenly distributed on at least one cross-section of the half-shaft. The magnets are spherical, cylindrical, or square in shape. The magnetic poles of two adjacent magnets are arranged radially and axially along the half-shaft, respectively. The magnets with magnetic poles arranged radially and axially along the half-shaft are called radial magnets and axial magnets, respectively. The mid-sections of the radial magnets and axial magnets are coplanar. The mid-section of the magnet refers to the cross-section passing through the center point of the magnet along the axial direction of the half-shaft.

[0005] The transducer consists of two cantilevered oscillators separated by an insulating spacer. The cantilevered oscillators are piezoelectric-friction composite oscillators. Each cantilevered oscillator is composed of a metal sheet and a friction plate bonded to one side, or a metal sheet and friction plates and piezoelectric plates bonded to both sides respectively. The thickness of the spacer is twice the thickness of the friction plates. Under natural conditions without external force, both cantilevered oscillators in the transducer are in a straight state and their friction plates are in close contact with each other. The contact surface of the two friction plates is the friction pair interface. The metal sheet is made of a ferromagnetic metal, such as nickel, cobalt, and their alloys. The two friction plates in the same transducer are made of two different materials with relatively large triboelectric series.

[0006] The housing consists of a side wall and a bottom wall. The side wall is a cylindrical structure with a flange on its outer edge and an annular platform on its inner edge. The end face of the annular platform is evenly distributed with grooves. The bottom wall has only a bottom wall hole at its center, or the bottom wall has a bottom wall hole and an inner barrel at its center, with the side wall port of the inner barrel serving as the bottom wall hole. The side wall and bottom wall form a housing cavity, making the housing a single-cavity housing. Alternatively, the side wall, bottom wall, and inner barrel form a housing cavity and an inner barrel cavity, which are not connected, making the housing a double-cavity housing.

[0007] The cover is screwed onto the housing, and the cover is screwed onto the end of the housing cavity. The housing and cover are made of non-ferromagnetic material. The transducer is screwed onto the ring platform on the side wall of the housing, and the fixed end of the transducer is placed in the groove of the ring platform. The sensor and circuit board are installed on the housing or cover. The circuit board is equipped with an electrical energy conversion and information transmission unit. Each cantilever oscillator is connected to the circuit board via independent wires and rectifiers.

[0008] The housing and half-shaft are respectively mounted on the outer ring and the main shaft. The shaft disc at the end of the half-shaft is mounted on the main shaft with screws, and the flange of the housing is mounted on the end of the outer ring with screws. The exciter, i.e. the part of the half-shaft with the magnet embedded in it, is placed inside the housing. The half-shaft is placed in the housing cavity or the inner barrel cavity. When the half-shaft is placed in the housing cavity, a sealing ring is provided between the bottom wall of the housing and the shaft disc.

[0009] The interface of the friction pair of the transducer is coplanar with the cross section of the magnet. The ends of the transducer are not simultaneously opposite to the two magnets. The number of transducers and the number of magnets are coprime on the same circumference.

[0010] In this invention, the exciter is mounted on the outer ring, and the housing is mounted on the main shaft and the inner ring. At this time, the structure of the half shaft and the housing needs to be adjusted appropriately. The specific structural diagram is omitted.

[0011] In this invention, a cylindrical axial magnet opposite to a transducer can be replaced with two magnets arranged axially along the semi-axis.

[0012] During operation, the inner and outer rings rotate relative to each other, and the main shaft drives the exciter and transducer to rotate relative to each other. The radial magnet and the axial magnet alternately approach and move away from the transducer. The metal plates of the two cantilever oscillators in the same transducer undergo reciprocating bending deformation in opposite directions under the alternating action of the radial magnet and the axial magnet. This causes the two friction plates to reciprocate contact-separation motion, and the stress of the two piezoelectric plates to alternately increase and decrease. Then, through the friction effect and the piezoelectric effect, the mechanical motion energy of the cantilever oscillator is converted into electrical energy. After conversion, the electrical energy is supplied to the sensor. The sensor obtains relevant information such as temperature, vibration or speed and sends it out, completing the self-powered monitoring of the bearing and gearbox.

[0013] In this invention, the exciter rotates and causes the radial and axial magnets to alternately move closer to and away from the transducer. The vibration process of the two cantilever oscillators is as follows: ① When the axial magnet approaches, the two magnetic poles of the axial magnet are located on both sides of the interface of the transducer friction pair. The two cantilever oscillators are located on both sides of the magnetic pole interface and are subjected to the attraction of the magnetic pole on their respective sides. The two cantilever oscillators produce bending deformation that separates them from each other. Since the attraction is greatest at the apex of the spherical magnet and the extreme point of the cylindrical magnet, the two cantilever oscillators will produce equal-amplitude or limited-amplitude deformation when other conditions are the same. This avoids excessive deformation that could cause the piezoelectric sheet to break or plastic deformation that could affect the adhesion of the friction sheet. When subjected to the action of the axial magnet, the bending deformation of the free end of the cantilever oscillator is close to the radius of the spherical magnet or half the length of the cylindrical magnet. At this time, the friction sheet completely disengages from the contact and the stress of the piezoelectric sheet reaches its maximum.

[0014] ② When the radial magnet approaches, only one magnetic pole is opposite the transducer and the center point of the magnetic pole with the greatest attraction is located on the interface of the friction pair of the transducer. That is, the two cantilever oscillators are located on both sides of the center point of the magnetic pole. The radial magnet generates an attraction force on the two cantilever oscillators, causing them to move closer to each other. Under the action of its own elastic force and the attraction force of the radial magnet, the cantilever oscillator resets. After the cantilever oscillator resets, the two friction plates are completely in contact with each other and the stress of the piezoelectric plate drops to zero.

[0015] During the reciprocating bending deformation process of the above-mentioned cantilever oscillator, piezoelectric and triboelectric power generation are realized simultaneously, resulting in a high energy density per unit volume. The free end of the cantilever oscillator does not require the installation of magnets, making it simple in structure, small in size, easy to integrate and excite, and with a wide effective frequency band, which cannot be achieved by the traditional magnetic coupling excitation method. The cantilever oscillator is lightweight and has low inertial force, making it easy to achieve equal-radial excitation. The piezoelectric element is only subjected to compressive stress with controllable magnitude, resulting in high reliability.

[0016] Advantages and features: Simultaneous piezoelectric and triboelectric power generation, resulting in high energy density per unit volume; the transducer does not require the installation of magnets, has a simple structure, small size, light weight, wide effective frequency band, and is easy to integrate and excite, whereas the traditional method of using magnets cannot achieve synchronous power generation; the cantilever oscillator is subjected to equal-radial excitation, and the piezoelectric element is only subjected to compressive stress with controllable magnitude, resulting in high reliability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the monitoring device in a preferred embodiment of the present invention when a dual-cavity housing is used; Figure 2 yes Figure 1 AA section view; Figure 3 This is a schematic diagram of a preferred embodiment of the present invention, showing that the housing has a dual-cavity structure. Figure 4 yes Figure 3 The left view; Figure 5 This is a schematic diagram of the structure of a preferred embodiment of the present invention when the exciter uses a spherical magnet; Figure 6 This is a schematic diagram of the structure of the exciter in a preferred embodiment of the present invention when a columnar magnet is used; Figure 7 This is a schematic diagram of the monitoring device in a preferred embodiment of the present invention when a single-cavity housing is used; Figure 8 This is a schematic diagram of a preferred embodiment of the present invention, showing that the housing has a single cavity structure. Detailed Implementation

[0018] This invention proposes a rolling bearing and gearbox self-monitoring device, comprising a bearing B, a main shaft C, and a monitoring unit D. The bearing B consists of an inner ring x, an outer ring y, and rolling elements z. The monitoring unit D mainly consists of a housing a, a cover b, a circuit board c, an actuator G, a transducer E, and a sensor s. The inner ring x of the bearing B is mounted on the main shaft C, and the outer ring y is mounted on the inner ring x via the rolling elements z. The rolling elements z can be balls, cylindrical rollers, or tapered rollers. The bearings formed using these three types of rolling elements z are ball bearings, cylindrical roller bearings, and tapered roller bearings. The housing a and the actuator are respectively mounted on the inner ring x and the outer ring y, or the outer ring y and the inner ring x. The following is a specific method for mounting the housing a and the actuator G on the outer ring y and the inner ring x, respectively. The actuator G is mounted on the inner ring x via the main shaft C.

[0019] The exciter G consists of a semi-shaft d and magnets e evenly distributed along its circumference. The semi-shaft d is made of a non-ferromagnetic material. Magnets e are evenly distributed on at least one cross-section of the semi-shaft d. The magnets e are spherical, cylindrical, or square in shape. The magnetic poles of two adjacent magnets e are arranged radially and axially along the semi-shaft d, respectively. The magnets e with magnetic poles arranged radially and axially along the semi-shaft d are called radial magnets and axial magnets, respectively. The mid-sections e1 of the radial magnets and axial magnets are coplanar. The mid-section e1 of the magnets refers to the cross-section passing through the center point of the magnet e along the axial direction of the semi-shaft d.

[0020] Transducer E consists of two cantilever oscillators i separated by an insulating spacer g. The cantilever oscillator i is a piezoelectric-friction composite oscillator. The cantilever oscillator i is composed of a metal sheet i1 and a friction plate i2 bonded to one side, or the cantilever oscillator i is composed of a metal sheet i1 and friction plates i2 and piezoelectric plates i3 bonded to both sides respectively. The thickness of the spacer g is twice the thickness of the friction plate i2. Under natural conditions without external force, the two cantilever oscillators i in transducer E are both in a straight state and their friction plates i2 are in contact with each other. The contact surface of the two friction plates i2 is the friction pair interface E1. The material of the metal sheet i1 is a ferromagnetic metal, such as nickel, cobalt and their alloys. The materials of the two friction plates i2 in the same transducer are two different materials with a relatively large triboelectric series.

[0021] The housing a is composed of a side wall a4 and a bottom wall a3. The side wall a4 is a cylindrical structure. The outer edge of the side wall a4 is provided with a flange a8 and the inner edge is provided with a ring platform a6. The end face of the ring platform a6 is evenly distributed with grooves a7. The bottom wall a3 has only a bottom wall hole a2 at its center, or the bottom wall a3 has a bottom wall hole a2 and an inner barrel a5 at its center. The side wall port of the inner barrel a5 is the bottom wall hole a2. The side wall a4 and the bottom wall a3 form a cavity a7, and the housing a is a single cavity housing. Alternatively, the side wall a4, the bottom wall a3 and the inner barrel a5 form a cavity a7 and an inner barrel cavity a9. The cavity a7 and the inner barrel cavity a9 are not connected, and the housing a is a double cavity housing.

[0022] The cover b is screwed onto the housing a, and the cover b is screwed onto the end of the housing cavity a7. The housing a and the cover b are made of non-ferromagnetic material. The transducer E is screwed onto the ring platform a6 on the side wall a4 of the housing a6 and the pressure block f is used to mount the fixed end of the transducer E in the recess a7 of the ring platform a6. The sensor s and the circuit board c are mounted on the housing a or the cover b. The circuit board c is equipped with an electrical energy conversion and processing and information transmission unit. Each cantilever oscillator i is connected to the circuit board c via independent wires and rectifiers.

[0023] The housing a and the half shaft d are respectively mounted on the outer ring y and the main shaft C. The shaft disc d1 at the end of the half shaft d is mounted on the main shaft C by screws. The flange a8 of the housing a is mounted on the end of the outer ring y by screws. The exciter G, that is, the part of the half shaft d with the magnet e embedded in it, is placed inside the housing a. The half shaft d is placed in the housing cavity a7 or the inner barrel cavity a9. When the half shaft d is placed in the housing cavity a7, a sealing ring t is provided between the bottom wall a3 of the housing and the shaft disc d1.

[0024] The friction pair interface E1 of transducer E is coplanar with the mid-section e1 of magnet. The ends of transducer E are not simultaneously opposite to the two magnets e. The number of transducers E evenly distributed on the same circumference is coprime to the number of magnets e.

[0025] In this invention, the exciter G is mounted on the outer ring y, and the housing a is mounted on the main shaft C and the inner ring x. At this time, the structure of the half shaft d and the housing a needs to be adjusted appropriately. The specific structural diagram is omitted.

[0026] In this invention, a cylindrical axial magnet opposite to a transducer E can be replaced with two magnets e arranged axially along the semi-axis d.

[0027] During operation, the inner ring x rotates relative to the outer ring y. The main shaft C drives the exciter G to rotate relative to the transducer E. The radial magnet and the axial magnet alternately approach and move away from the transducer E. The metal plates i1 of the two cantilever oscillators i in the same transducer undergo reciprocating bending deformation in opposite directions under the alternating action of the radial magnet and the axial magnet. This causes the two friction plates i2 to undergo reciprocating contact-separation motion, and causes the stress of the two piezoelectric plates i3 to alternately increase and decrease. The transducer E converts the mechanical motion energy of the cantilever oscillator i into electrical energy through friction and piezoelectric effects. After conversion, the electrical energy is supplied to the sensor s. The sensor s obtains relevant information such as temperature, vibration or rotation speed and transmits it out, completing the self-powered monitoring of the bearing and gearbox.

[0028] In this invention, the exciter G rotates and causes the radial and axial magnets to alternately move closer to and away from the transducer E. The vibration process of the two cantilever oscillators i is as follows: ① When the axial magnet approaches, the two magnetic poles of the axial magnet are located on both sides of the friction pair interface E1 of the transducer E. The two cantilever oscillators i are located on both sides of the magnetic pole interface e1 and are respectively subjected to the attraction of the magnetic pole on their respective sides. The two cantilever oscillators i produce bending deformation that separates from each other. Since the attraction is greatest at the apex of the spherical magnet and the extreme point of the cylindrical magnet, the two cantilever oscillators i will produce equal-radius or limited-amplitude deformation when other conditions are the same. This avoids excessive deformation that could cause the piezoelectric sheet to break or plastic deformation that could cause the friction sheet i2 to stick together. When subjected to the action of the axial magnet, the bending deformation of the free end of the cantilever oscillator i is close to the radius of the spherical magnet e or half the length of the cylindrical magnet e. At this time, the friction sheet i2 completely disengages from the contact and the stress of the piezoelectric sheet i3 reaches its maximum.

[0029] ② When the radial magnet approaches, only one magnetic pole is opposite to the transducer E, and the center point of the magnetic pole with the greatest attraction is located on the friction pair interface of the transducer E. That is, the two cantilever oscillators i are located on both sides of the center point of the magnetic pole. The radial magnet generates an attraction force on the two cantilever oscillators i, causing them to move closer to each other. Under the action of its own elastic force and the attraction force of the radial magnet, the cantilever oscillator i resets. After the cantilever oscillator i resets, the two friction plates i2 are completely attached to each other, and the stress of the piezoelectric plate i3 drops to zero.

[0030] During the reciprocating bending deformation process of the aforementioned cantilever oscillator i, piezoelectric and triboelectric power generation are achieved simultaneously, resulting in a high energy density per unit volume. The free end of the cantilever oscillator i does not require the installation of a magnet, making it simple in structure, small in size, easy to integrate and excite, and with a wide effective frequency band, which cannot be achieved by the traditional magnetic coupling excitation method. The cantilever oscillator i is lightweight and has low inertial force, making it easy to achieve equal-radial excitation. The piezoelectric element is only subjected to compressive stress with controllable magnitude, resulting in high reliability.

Claims

1. A rolling bearing and gearbox self-monitoring device, comprising a bearing mounted on a main shaft and a monitoring unit, wherein the monitoring unit comprises a housing, a cover, a circuit board, an actuator, a transducer, and a sensor; the housing comprises side walls and a bottom wall; the cover is mounted on the housing; and the housing and the actuator are respectively mounted on the outer ring and the inner ring; characterized in that: The exciter consists of a semi-axis and magnets evenly distributed along its circumference. The magnets are spherical, cylindrical, or square. The magnetic poles of two adjacent magnets are arranged radially and axially along the semi-axis, respectively. These magnets are called radial magnets and axial magnets, and their mid-sections are coplanar. The mid-section of a magnet refers to the cross-section passing through the axial center point of the magnet along the semi-axis. The transducer consists of two cantilever oscillators, each composed of a metal sheet and friction plates and piezoelectric plates bonded to its two sides. When no external force is applied, both cantilever oscillators in the transducer are in a flat position. In a straight state, the friction plates are in close contact with each other, and the contact surface of the friction plates is the friction pair interface; the transducer is mounted on the side wall of the housing, and the transducer and exciter are placed inside the housing. The cross section of the magnet is coplanar with the friction pair interface; during operation, the exciter and the transducer rotate relative to each other, the radial magnet and the axial magnet alternately approach and move away from the transducer, the two cantilever oscillators in the same transducer undergo reciprocating bending deformation in opposite directions, the two friction plates reciprocate contact and separation, the stress of the piezoelectric plate alternately increases and decreases, the transducer generates electricity through friction and piezoelectric effects, and the electrical energy supplies the sensor and information transmission system and completes self-powered monitoring.

2. The self-monitoring device for rolling bearings and gearboxes according to claim 1, characterized in that: The metal sheet is made of ferromagnetic metal, and the two friction plates in the same transducer are made of two different materials. The housing, cover and half shaft are made of non-ferromagnetic materials.

3. The self-monitoring device for rolling bearings and gearboxes according to claim 1, characterized in that: The transducer ends are not simultaneously opposite to two magnets; a single cylindrical axial magnet is replaced by two magnets arranged axially along the semi-axis.

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