CN107395050B - A high-speed rail shaft monitoring device - Google Patents

Abstract

The invention relates to a high-speed rail shaft system monitoring device, which belongs to the field of rail vehicle monitoring and piezoelectric power generation. The wheel shaft is installed on the frame through the bearing, and the end of the shell of the frame is equipped with an end cover; the end of the wheel shaft is equipped with a cylindrical cam with a cam groove, and one end of the cylindrical cam is sleeved on the wheel shaft and leans against the inner ring of the bearing The boss of the shell of the frame is equipped with a piezoelectric vibrator and a reed, and the free end of the reed is equipped with an exciter through a rivet. The exciter is provided with a top block and a guide post. It is cylindrical or spherical, and the rolling element is placed in the cam groove; the piezoelectric vibrator is formed by bonding the substrate and the piezoelectric sheet. The piezoelectric vibrator is symmetrically installed on both sides of the reed and the substrate is installed close to the reed. The substrate and the reed Gaskets are crimped between them, and the free end of the piezoelectric vibrator leans against the top block; a circuit board and a sensor are installed on the vehicle frame, the piezoelectric vibrator is connected to the circuit board through wires, and the circuit board is connected to the sensor through wires.

Description

A high-speed rail shaft system monitoring device

Technical Field

The present invention belongs to the technical field of rail transit monitoring and piezoelectric power generation, and in particular relates to a high-speed rail shaft system monitoring device.

Background Art

Wheelsets are key components of rail vehicles, and their health status was previously guaranteed through regular maintenance and inspection. With the continuous increase in vehicle speed and the improvement of people's safety awareness, the research on real-time online monitoring technology of wheelsets during vehicle operation has attracted widespread attention from scholars at home and abroad. The required monitoring factors include temperature, speed, dynamic stiffness, wear and vibration of shafts and bearings. For the wheelset monitoring system, the ideal method is to install various sensor monitoring systems on or near the wheelset to achieve direct online monitoring of its operating status; however, this monitoring scheme is difficult to promote and apply because it cannot provide a reliable and sufficient power supply for the sensor monitoring system, because: the wheel system is in motion, and there is high-frequency bump vibration between the wheel system and the carriage, and the reliability is low when the cable is used for power supply; if the battery is used for power supply, it needs to be replaced frequently due to its limited service life. When the battery is insufficient and not replaced in time, effective monitoring cannot be achieved, and even serious safety hazards will be caused. Limited by the constraints of power supply problems, non-real-time and indirect measurement methods are still widely used, that is, the sensor monitoring system is placed on the roadbed, which does not move with the vehicle body or rotate with the wheel axle. In order to solve the power supply problem of the real-time monitoring system of the train axle system, domestic and foreign scholars have proposed a miniature piezoelectric generator that can be integrated with the monitoring system. However, the existing piezoelectric generator is periodically excited and the piezoelectric sheet is subjected to alternating tensile and compressive stresses, so the reliability is low and the effective bandwidth is narrow.

Summary of the invention

The present invention proposes a high-speed railway shaft system monitoring device, and the implementation scheme adopted by the present invention is: the wheel axle is installed on the frame through the bearing, and the end of the frame shell is installed with an end cover through screws; a cylindrical cam with a cam groove is installed on the end of the wheel axle through a pressure plate and screws, one end of the cylindrical cam is sleeved on the wheel axle and rests on the inner ring of the bearing; a piezoelectric vibrator and a spring are installed on the boss of the frame shell through a pressure block and screws, an exciter is installed on the free end of the spring through rivets, a top block and a guide column are provided on the exciter, a rolling body is sleeved on the guide column, the rolling body is cylindrical or spherical, and the rolling body is placed in the cam groove; the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, the piezoelectric vibrator is symmetrically installed on both sides of the spring and the substrate is installed close to the spring, a gasket is crimped between the substrate and the spring, and the free end of the piezoelectric vibrator rests on the top block; a circuit board and a sensor are installed on the frame, the piezoelectric vibrator is connected to the circuit board through a wire, and the circuit board is connected to the sensor through a wire.

其中：B＝1-α+αβ，A＝α⁴(1-β)²-4α³(1-β)+6α²(1-β)-4α(1-β)+1，

α＝h_m/H，β＝E_m/E_p，h_m和H为别为基板的厚度和压电振子总厚度，E_m和E_p分别为基板和压电片的杨氏模量，k₃₁和

分别为压电陶瓷材料的机电耦合系数和许用压应力，L为压电振子的长度。The piezoelectric vibrator is a straight structure before installation and a curved structure after installation; when the spring does not bend and deform, the deformation and stress state of the piezoelectric vibrators on both sides of the spring are the same, and the maximum stress on the piezoelectric sheet is half of its allowable value; when the rolling element and the vertex of the left cam surface or the vertex of the right cam surface of the cam groove contact each other and the bending deformation of the spring reaches the maximum, the maximum compressive stress on the piezoelectric sheet is not greater than its allowable value, and the deformation of the free end of the piezoelectric vibrator is not greater than its allowable deformation, that is, less than

Among them: B=1-α+αβ, A=α ⁴ (1-β) ² -4α ³ (1-β)+6α ² (1-β)-4α(1-β)+1,

α＝ _hm /H，β＝ _Em / _Ep ， _hm and H are the thickness of substrate and total thickness of piezoelectric vibrator, _respectively . _Em and _Ep are Young's modulus of substrate and piezoelectric sheet, respectively.

are the electromechanical coupling coefficient and allowable compressive stress of the piezoelectric ceramic material respectively, and L is the length of the piezoelectric vibrator.

During operation, the wheel shaft drives the cylindrical cam to rotate, and the rolling body reciprocates in the cam groove along the axial direction of the cylindrical cam, and then the piezoelectric vibrator is stimulated to vibrate reciprocatingly by the exciter, thereby converting mechanical energy into electrical energy: when the spring leaf bends and deforms, the force and deformation of the top block on the piezoelectric vibrator on one side gradually increase, and the compressive stress on the piezoelectric piece gradually increases but does not exceed the allowable value; the piezoelectric vibrator on the other side gradually resets under the action of its own elastic force, and the compressive stress on the piezoelectric piece gradually decreases but does not cause tensile stress; the electrical energy generated by the piezoelectric vibrator is processed by the conversion circuit on the circuit board to power the sensor, and the sensor obtains the temperature, speed or vibration information of the bearing in real time and transmits it through the wireless transmission system.

Advantages and features: During operation, the piezoelectric vibrator is deformed by unidirectional excitation, and the piezoelectric sheet only bears compressive stress, thus avoiding damage due to excessive tensile stress and having high reliability. At any speed, the deformation of the piezoelectric vibrator is half of the cam lift, so it has high reliability, wide effective bandwidth, and strong power generation and supply capabilities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a structural cross-sectional view of a monitoring device in a preferred embodiment of the present invention;

FIG2 is a schematic diagram of the structure of a cam in a preferred embodiment of the present invention;

FIG3 is a schematic diagram of the structure of an exciter and a rolling element after assembly in a preferred embodiment of the present invention;

Fig. 4 is a left side view of Fig. 3;

Fig. 5 is a cross-sectional view taken along line A-A of Fig. 1;

FIG. 6 is a cross-sectional view of the structure of the monitoring device shown in FIG. 1 after the axle is rotated 180 degrees.

DETAILED DESCRIPTION

The wheel shaft a is installed on the frame c through the bearing b, and the end of the shell c1 on the frame c is installed with an end cover d through screws; the end of the wheel shaft a is installed with a cylindrical cam f with a cam groove f1 through a pressure plate e and screws, and one end of the cylindrical cam f is sleeved on the wheel shaft a and rests on the inner ring of the bearing b; the piezoelectric vibrator h and the reed i are installed on the boss of the shell c1 of the frame c through a pressure block g and screws, and the exciter j is installed on the free end of the reed i through rivets, and the exciter j is provided with a top block j1 and a guide column j2, and the guide column j2 is sleeved There is a rolling body k, which is cylindrical or spherical and is placed in the cam groove f1; the piezoelectric vibrator h is formed by bonding a substrate h1 and a piezoelectric sheet h2, the piezoelectric vibrator h is symmetrically installed on both sides of the reed i and the substrate h1 is installed close to the reed i, a gasket m is crimped between the substrate h1 and the reed i, and the free end of the piezoelectric vibrator h rests on the top block j1; a circuit board n and a sensor p are installed on the frame c, the piezoelectric vibrator h is connected to the circuit board n via a wire, and the circuit board n is connected to the sensor p via a wire.

其中：B＝1-α+αβ，A＝α⁴(1-β)²-4α³(1-β)+6α²(1-β)-4α(1-β)+1，

α＝h_m/H，β＝E_m/E_p，h_m和H分别为基板h1的厚度和压电振子h的总厚度，E_m和E_p分别为基板h1和压电片h2的杨氏模量，k₃₁和

分别为压电陶瓷材料的机电耦合系数和许用压应力，L为压电振子h的长度。The piezoelectric vibrator h is a straight structure before installation and a curved structure after installation; when the spring i does not bend and deform, the deformation and stress state of the piezoelectric vibrators h on both sides of the spring i are the same, and the maximum stress on the piezoelectric sheet h2 is half of its allowable value; when the rolling element k contacts the vertex Z of the left cam surface or the vertex Y of the right cam surface of the cam groove f1 and the bending deformation of the spring i reaches the maximum, the maximum compressive stress on the piezoelectric sheet h2 is not greater than its allowable value, and the deformation of the free end of the piezoelectric vibrator h is not greater than its allowable deformation, that is, less than

Among them: B=1-α+αβ, A=α ⁴ (1-β) ² -4α ³ (1-β)+6α ² (1-β)-4α(1-β)+1,

α＝ _hm /H，β＝ _Em / _Ep ， _hm and H are the thickness of substrate h1 and the total thickness of piezoelectric vibrator h respectively, _Em and _Ep are the Young's modulus of substrate h1 and piezoelectric sheet h2 respectively, _k31 and

are the electromechanical coupling coefficient and allowable compressive stress of the piezoelectric ceramic material respectively, and L is the length of the piezoelectric vibrator h.

During operation, the wheel shaft a drives the cylindrical cam f to rotate, and the rolling body k reciprocates in the cam groove f1 along the axial direction of the cylindrical cam f, and then stimulates the piezoelectric vibrator h to vibrate reciprocatingly through the exciter j, thereby converting mechanical energy into electrical energy: when the reed i is bent and deformed, the force and deformation of the top block j1 on the piezoelectric vibrator h on one side gradually increase, and the compressive stress on the piezoelectric piece h2 gradually increases but does not exceed the allowable value; the piezoelectric vibrator h on the other side gradually resets under the action of its own elastic force, and the compressive stress on the piezoelectric piece h2 gradually decreases but does not cause tensile stress; the electrical energy generated by the piezoelectric vibrator h is processed by the conversion circuit on the circuit board n to power the sensor p, and the sensor p obtains the temperature, speed or vibration information of the bearing in real time and transmits it through the wireless transmission system.

Claims (1)

1. The utility model provides a high-speed railway shafting monitoring devices which characterized in that: the wheel axle is arranged on the frame through a bearing, and an end cover is arranged at the end part of the shell of the frame through a screw; the end part of the wheel shaft is provided with a cylindrical cam with a cam groove through a pressing plate and a screw, and one end of the cylindrical cam is sleeved on the wheel shaft and props against the inner ring of the bearing; the boss of the frame shell is provided with a piezoelectric vibrator and a reed through a pressing block and a screw, the free end of the reed is provided with an exciter through a rivet, the exciter is provided with a top block and a guide pillar, the guide pillar is sleeved with a rolling body, the rolling body is cylindrical or spherical, the rolling body is arranged in a cam groove, the cam groove is a groove formed on the circumferential side surface of a cylindrical cam, and the two side walls of the cam groove are provided with an apex and a bottom point along the circumferential direction; the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, the piezoelectric vibrator is symmetrically arranged on two sides of the reed, the substrate is arranged close to the reed, a gasket is pressed between the substrate and the reed, and the free end of the piezoelectric vibrator is propped against the top block; the piezoelectric vibrator is of a straight structure before installation and of a bent structure after installation; the frame is provided with a circuit board and a sensor, the piezoelectric vibrator is connected with the circuit board through a wire, and the circuit board is connected with the sensor through a wire; when the piezoelectric vibrator is in operation, the wheel shaft drives the cylindrical cam to rotate, the rolling bodies are alternately contacted with the top point of the left side wall cam surface or the top point of the right side wall cam surface of the cam groove, so that the rolling bodies do reciprocating motion in the cam groove along the axial direction of the cylindrical cam, and then the piezoelectric vibrator is excited to vibrate in a reciprocating mode through the exciter: when the reed is bent and deformed, the acting force and the deformation of the top block born by the piezoelectric vibrator on one side are gradually increased, and the compressive stress born by the piezoelectric sheet is gradually increased but not more than an allowable value; the piezoelectric vibrator on the other side gradually resets under the action of the self elastic force, and the compression stress born by the piezoelectric sheet gradually decreases but the tensile stress does not appear; the electric energy generated by the piezoelectric vibrator is processed by a conversion circuit on the circuit board to supply power for the sensor.

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