Energy-saving excitation aggregate screening device

Abstract

The invention discloses an energy-saving excitation aggregate screening device. The energy-saving excitation aggregate screening device comprises an excitation device, a piezoelectric device and a piezoelectric tray, the vibration excitation device comprises a shell and an eccentric wheel arranged in the shell, a plurality of piezoelectric devices are arranged in the shell and located on the rotating track of the eccentric wheel, and the piezoelectric devices output electric energy through piezoelectric excitation conversion; the piezoelectric tray comprises a tray rack, a sieve tray, a tray, a piezoelectric layer and a piezoelectric sensor; the tray rack is connected with the eccentric wheel through the conduction device, the sieve trays are stacked on the tray rack from top to bottom, the tray is arranged at the bottom of the lowest sieve tray, the piezoelectric layer is arranged in the tray, the piezoelectric layer generates piezoelectric excitation signals under the gravity action of aggregate screened by the lowest sieve tray, and the piezoelectric layer is connected with the piezoelectric sensor; the control unit determines a screening completion moment according to the piezoelectric excitation signal; according to the device, automatic identification of the screening completion moment is achieved, the self-power-supply function is achieved, and the problems that in the actual test process, each round of screening is long in time, low in efficiency, high in energy consumption and the like are solved.

Description

Technical Field

[0001] The present invention relates to the field of road engineering equipment, and in particular to an energy-saving vibration aggregate screening device. Background Art

[0002] Currently, highway aggregate screening tests primarily rely on manual experience to determine the screening endpoint, i.e., the time it takes for screening to be complete. Testers control the screening process based on empirical values ​​and a combination of timed or manual shutdowns. However, the operating parameters of the screening machine, such as vibration frequency, amplitude, and duration, are often set based on recommended values ​​in specifications, rather than real-time monitoring of the screening status. This results in the screening effect being significantly influenced by the operator's subjective influence. If the set time is too short, incomplete screening can easily occur. Therefore, to ensure sufficient screening, testers often use longer screening times, which increases redundant time. This is not only inefficient but also results in unnecessary energy waste. Existing screening equipment generally lacks intelligent monitoring methods and is unable to dynamically identify the degree of screening completion, resulting in poor screening quality stability. Furthermore, prolonged vibration can cause aggregate particles to break, affecting test accuracy.

[0003] Based on the above technical problems, this application designs a road aggregate screening machine based on piezoelectric technology. The road aggregate screening machine can be self-powered, and can automatically identify the time when screening is completed and shut down autonomously, thereby improving the accuracy of the test and reducing energy consumption. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides an energy-saving vibration aggregate screening device. The aggregate screening device is based on piezoelectric technology, which realizes automatic identification of the screening completion time and self-power supply function, thereby solving the disadvantages of long screening time, low efficiency and high energy consumption in each round of screening during actual experiments.

[0005] The present invention is achieved through the following technical solutions: An energy-saving vibration aggregate screening device, characterized by comprising a vibration device, a piezoelectric device and a piezoelectric tray; The excitation device includes a housing and an eccentric wheel disposed inside the housing. A plurality of piezoelectric devices are disposed in the housing and are located on the rotation trajectory of the eccentric wheel. The eccentric wheel can apply compressive stress to the piezoelectric devices during rotation, and the piezoelectric devices convert and output electrical energy through piezoelectric excitation. The piezoelectric tray includes a tray frame, a sieve tray, a tray, a piezoelectric layer and a piezoelectric sensor; The tray frame is connected to the eccentric wheel through a conducting device, and a plurality of sieve plates are stacked on the tray frame from top to bottom. The tray is arranged at the bottom of the lowest sieve plate, and the piezoelectric layer is arranged in the tray. The piezoelectric layer generates a piezoelectric excitation signal under the gravity of the aggregate sieved by the lowest sieve plate, and the piezoelectric layer is connected to the piezoelectric sensor; The vibration excitation device and the piezoelectric sensor are respectively connected to a control unit. The control unit determines the screening completion time according to the piezoelectric excitation signal and controls the operation of the vibration excitation device.

[0006] Preferably, the piezoelectric device comprises a stacked piezoelectric unit, an actuator and a pressure block; The stacked piezoelectric unit is fixed on the side wall of the shell, and the bottom of the actuating section is connected to the shell through a displacement structure. One end of the actuating section is used to apply pressure to the stacked piezoelectric unit, and the other end of the actuating section is connected to the pressure block, which is located on the rotation track of the eccentric wheel.

[0007] Preferably, an insulating actuating gasket is provided on the side of the pressure plate close to the stacked piezoelectric unit, and a side of the pressure block close to the eccentric wheel is an arc-shaped surface, the curvature of the arc-shaped surface is smaller than the curvature of the circular track of the eccentric wheel.

[0008] Preferably, the displacement structure is an elastic displacement structure or a sliding displacement structure.

[0009] Preferably, stacked piezoelectric units are respectively provided on both sides of the corners of the shell; The transmission joint includes a main actuating joint and a secondary actuating joint, one end of the two secondary actuating joints is connected to the two pressure plates respectively, and the other ends of the two secondary actuating joints are connected to the pressure block. The main actuating joint is located on the midline between the angles of the two secondary actuating joints, one end of the main actuating joint is connected to the ends of the two pressure plates close to each other through a connecting arm, and the other end of the main actuating joint is connected to the middle of the pressure block.

[0010] Preferably, the eccentric wheel is provided with a trigger block, which is used to apply tangential pressure to the pressure block; The trigger block is a protruding structure or a roller arranged on the side wall of the eccentric wheel.

[0011] Preferably, the transmission device includes a transmission rod and a base plate, with the center of the eccentric wheel as the midpoint, multiple transmission rods are evenly distributed on the eccentric wheel, the transmission base plate is fixed to the upper ends of the multiple transmission rods and is in a horizontal state, and the tray rack is fixed on the base plate.

[0012] Preferably, the piezoelectric layer is arranged in the tray, the piezoelectric sensor is fixed on the base tray, and the piezoelectric layer is pressed onto the piezoelectric sensor and electrically conductive.

[0013] Preferably, the sieve holes of the plurality of sieve plates decrease in size from top to bottom.

[0014] Preferably, a plurality of infrared sensors are arranged in a ring shape on the top of the shell of the excitation device, the infrared sensors are connected to the piezoelectric device, the infrared sensors emit infrared light vertically upward and are located outside the vibration range of the screen, and the infrared sensors are connected to the control unit.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The present application provides an energy-saving excitation aggregate screening device. The excitation device generates mechanical vibrations through an eccentric wheel, providing a power source for screening. A piezoelectric device is located on the rotational trajectory of the eccentric wheel and converts mechanical vibration energy into electrical energy to achieve energy recovery. The piezoelectric tray integrates a piezoelectric sensing function and monitors the aggregate sieving status in real time through the piezoelectric layer. The screening device can capture the aggregate sieving status of the bottom sieve plate in real time through the cooperation of the piezoelectric layer and the piezoelectric sensor. When the piezoelectric excitation signal disappears continuously for a set time, the control unit can automatically determine that the screening is complete and shut down. This completely solves the problems of insufficient screening or time redundancy in traditional manual judgment methods and significantly improves the screening accuracy and consistency. Secondly, the piezoelectric device converts the mechanical energy of the eccentric wheel rotation into electrical energy through the positive piezoelectric effect. This not only realizes the self-powered device and reduces the dependence on external energy, but also powers the control system and sensors. In addition, the device adopts a compact integrated design for the excitation device, energy recovery module and screening tray. The mechanical connection and signal transmission between the components are optimized, which not only ensures the stability of the system but also facilitates maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic structural diagram of an energy-saving vibration aggregate screening device according to the present invention; Figure 2 The motion trajectory diagram of the eccentric shaft of the present invention; Figure 3 is a top view of the piezoelectric device of the present invention; Figure 4 It is a structural schematic diagram of the actuator section of the present invention; Figure: excitation device 1, tray rack 2, piezoelectric tray 3, conduction device 4, piezoelectric device 5, controller 11, infrared sensor 12, lighting lamp 13, pressure plate 21, support rod 22, fastening nut 23, support 24. Sieve plate 31, tray 32, piezoelectric sensor 41, base plate 42, eccentric wheel 43, transmission rod 44, trigger block 45, actuator 51, flexible rubber pad 52, insulating actuator spacer 53, stacked piezoelectric unit 54, integrated piezoelectric capacitor 55, cable 56, auxiliary actuator 57, main actuator 58. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0021] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of the invention is usually placed when in use. This is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0022] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art can understand the specific meanings of the above terms in this application based on specific circumstances.

[0024] See Figure 1-4 , an energy-saving vibration aggregate screening device, comprising a vibration device 1, a piezoelectric device 5 and a piezoelectric tray 3; The excitation device 1 includes a housing and an eccentric wheel 43 disposed therein. A plurality of piezoelectric devices 5 are disposed in the housing and located on the rotational trajectory of the eccentric wheel 43. During rotation, the eccentric wheel 43 can apply compressive stress to the piezoelectric devices 5. The piezoelectric devices 5 convert and output electrical energy through piezoelectric excitation. The piezoelectric tray includes a tray frame 2, a sieve tray 31, a tray 32, a piezoelectric layer and a piezoelectric sensor 41; The tray frame 2 is connected to the eccentric wheel 43 via a conducting device 4. A plurality of sieve trays 31 are stacked on the tray frame 2 from top to bottom. The tray 32 is provided at the bottom of the lowest sieve tray 31. The piezoelectric layer is provided at the bottom of the tray 32. The piezoelectric layer generates a piezoelectric excitation signal under the action of gravity of the aggregate sieved from the upper sieve tray 31. The excitation device 1 and the piezoelectric sensor 41 are respectively connected to the control unit, and the control unit controls the screening completion time according to the piezoelectric excitation signal.

[0025] In some embodiments, a driving motor is provided in the housing of the excitation device, the axis of the eccentric wheel 43 is fixedly connected to the output shaft of the eccentric motor, the driving motor is connected to the control unit, and the driving motor drives the eccentric wheel 43 to rotate. The centrifugal force during rotation causes the screening machine to generate periodic vibrations, driving the sieve plate 31 to perform periodic reciprocating vibrations, thereby realizing layer-by-layer screening of the aggregate in the sieve plate 31.

[0026] At the same time, since multiple piezoelectric devices 5 are respectively arranged on the rotation trajectory of the eccentric wheel 43, the eccentric wheel 43 can periodically apply compressive stress to each piezoelectric device 5 during rotation, so that the piezoelectric device 5 generates electrical energy, and the generated electrical energy is used to function as the entire vibration aggregate screening device.

[0027] In some embodiments, the piezoelectric device 5 includes a stacked piezoelectric unit 54 , an actuator 51 , and a pressure block.

[0028] The stacked piezoelectric unit 54 is fixed on the side wall of the shell, and the bottom of the actuating joint 51 is connected to the shell through a displacement structure. One end of the actuating joint 51 is in contact with the stacked piezoelectric unit 54, and the other end of the actuating joint 51 is connected to the pressure block. The pressure block is located on the track of the eccentric wheel 43. During the rotational movement of the eccentric wheel 43, the outer circle of the eccentric wheel 43 can exert tangential pressure on the pressure block, thereby causing the actuating joint 51 to displace. The end of the actuating joint 51 applies compressive stress to the stacked piezoelectric unit 54, and the stacked piezoelectric unit 54 generates electrical energy and stores it.

[0029] The stacked piezoelectric unit 54 is constructed from multiple layers of piezoelectric ceramic sheets, such as PZT. Each sheet is coated with electrodes and connected in series via conductive adhesive or metal foil. Metal end plates are provided at each end for power output, and the entire unit is secured with pre-tightened bolts to enhance tensile strength. The actuator 51 and pressure block mechanically link it to the eccentric 43. Rotation of the eccentric 43 periodically compresses the pressure block, causing the actuator 51 to transmit axial pressure to the stacked unit.

[0030] Due to the direct piezoelectric effect, when the eccentric 43 applies a tangential force to the pressure block, the actuator 51 transmits the pressure to the stacked piezoelectric unit 54. The axial compression of the piezoelectric ceramics causes charge separation, which in turn outputs a transient current. After the eccentric 43 disengages, an elastic displacement structure, such as a metal spring, resets the actuator 51, unloading the stress from the piezoelectric unit. The current from the multiple ceramics is combined and stored in the integrated piezoelectric capacitor 55, providing power for the device.

[0031] This design efficiently converts the vibrating mechanical energy of the screening machine into electrical energy, reducing the need for external power supply; the stack structure improves power generation density while providing stable energy for lighting, sensors, etc., achieving energy saving and intelligent control.

[0032] Optionally, a pressure plate is provided at one end of the action node close to the stacked piezoelectric unit 54. The area of ​​the pressure plate is opposite to the stacked piezoelectric unit 54 and is the same as the area of ​​the stacked piezoelectric unit 54. When the action node is displaced, the pressure plate exerts time pressure on the stacked piezoelectric unit 54. Since the area of ​​the pressure plate is the same as the area of ​​the stacked piezoelectric unit 54, the maximum actuating area can be applied to the stacked piezoelectric unit 54, so that the power generation efficiency of the stacked piezoelectric unit 54 is maximized.

[0033] Furthermore, an insulating actuating gasket 53 is provided on one side of the pressure plate close to the stacked piezoelectric unit 54. The insulating actuating gasket 53 applies pressure to the stacked piezoelectric unit 54. When the eccentric shaft is separated from the pressure block, the insulating actuating gasket 53 is reset under the action of the elastic force, that is, the insulating actuating gasket 53 is separated from the stacked piezoelectric unit 54, or is only in contact with the stacked piezoelectric unit 54. It should be noted that when the insulating actuating gasket 53 and the stacked piezoelectric unit 54 are in contact, no pressure is applied to the stacked piezoelectric unit 54, and the stacked piezoelectric unit 54 does not generate electrical energy.

[0034] The insulating actuating gasket 53 is made of insulating rubber.

[0035] Furthermore, the side of the pressure block close to the eccentric wheel 43 is an arc surface. During the rotation of the eccentric wheel 43, the side wall of the eccentric wheel 43 contacts the arc surface to generate tangential pressure. The tangential pressure gradually increases and gradually decreases after reaching the maximum value.

[0036] The tangential pressure between the eccentric wheel 43 and the arc surface at the initial contact position is 0. At this time, the actuator joint 51 does not generate displacement. When the eccentric wheel 43 continues to rotate, the tangential pressure on the arc surface gradually increases, that is, the displacement of the actuator joint 51 increases synchronously. When the displacement reaches the maximum, the eccentric wheel 43 gradually separates from the arc surface, and the tangential pressure gradually decreases. At the same time, the actuator joint 51 resets until the eccentric wheel 43 is completely separated from the arc surface, that is, the insulating actuator gasket 53 is separated from the stacked piezoelectric unit 54, or only contacts.

[0037] Furthermore, the curvature of the arc surface is smaller than the curvature of the circular trajectory of the eccentric wheel 43, so as to avoid the collision between the eccentric wheel 43 and the end of the pressure block. It can also be understood that the diameter of the arc surface is larger than the diameter of the circular trajectory of the eccentric wheel 43. This design avoids the problem of collision between the eccentric wheel 43 and the end of the arc surface of the pressure plate. During the rotation of the eccentric wheel 43, by controlling the curvature of the arc surface, the maximum outer diameter position of the side wall of the eccentric wheel 43 enters the arc surface area and contacts it to apply pressure.

[0038] Furthermore, a flexible pad layer 52 is attached to the arc surface, and the eccentric wheel 43 directly contacts the flexible pad layer 52 to apply pressure, thereby reducing the noise during the contact process between the two, while avoiding wear of the eccentric wheel 43 and the arc surface during periodic rotation, thereby increasing the service life of the stacked piezoelectric unit 54.

[0039] In some embodiments, the displacement structure is an elastic displacement structure or a sliding displacement structure.

[0040] The elastic displacement structure includes an elastic arm, which is vertically arranged. The upper end of the elastic arm is fixedly connected to the bottom of the actuating section 51, and the lower end of the elastic arm is connected to the bottom of the shell of the excitation device 1. When the eccentric wheel 43 applies tangential pressure to the pressure block, the elastic arm is deformed, and the actuating section 51 applies pressure to the stacked piezoelectric unit 54. When the eccentric wheel 43 separates from the pressure block, the elastic arm is reset, and the actuating section 51 separates and resets the stacked piezoelectric unit 54.

[0041] The elastic arm is a metal spring plate or a spring.

[0042] The metal spring plate includes a fixed arm and a bent wall. The lower end of the fixed arm is fixedly connected to the shell, the lower end of the bent wall is connected to the upper end of the fixed arm, and the upper end of the bent wall is inclined toward the eccentric wheel 43. An angle is formed between the fixed arm and the bent wall. The fixed arm and the bent wall adopt an integrated structure and are made by a bending process. The metal spring plate adopts elastic steel to produce a rebound effect of movement. When the actuator 51 moves toward the stacked piezoelectric unit 54 under pressure, the metal spring plate undergoes lateral bending deformation. When the eccentric wheel 43 is separated from the stacked piezoelectric unit 54, the metal spring plate drives the actuator 51 to reset under the action of elastic force.

[0043] The sliding displacement structure includes a slide groove and a slider; The slide groove is set on the bottom surface of the shell, the lower end of the slider is set in the slide groove, the upper end of the slider is fixed to the actuating joint 51, and a pressure plate is set at the end of the actuating joint 51. The end face of the pressure plate is set with elastic insulating rubber. When the pressure plate applies pressure to the stacked piezoelectric unit 54, the insulating rubber is deformed, thereby resetting the actuating joint 51 and eliminating the pressure between the pressure plate and the stacked piezoelectric unit 54. At this time, the pressure plate and the stacked piezoelectric unit 54 are in contact or a small gap is generated.

[0044] In some embodiments, the shell is a rectangular box structure, and multiple stacked piezoelectric units 54 and integrated piezoelectric capacitors 55 are arranged in series in the shell. A stacked piezoelectric unit 54 is arranged on both sides of the corner of the shell. The directions of the forces of the two stacked piezoelectric units 54 are perpendicular to each other, and the two stacked piezoelectric units 54 are connected to the actuator joint 51.

[0045] See Figure 4 The transmission joint includes a main actuating joint 58 and a secondary actuating joint 57. One end of the two secondary actuating joints 57 is connected to the two pressure plates respectively, and the other end of the two secondary actuating joints 57 is connected to the pressure block, and the two secondary actuating joints 57 are arranged perpendicular to each other. The main actuating joint 58 is located on the midline between the angles of the two secondary actuating joints 57. One end of the main actuating joint 58 is connected to the ends of the two pressure plates close to each other through a connecting arm, and the other end of the main actuating joint 51 is connected to the middle of the pressure block. The bottom of the main actuating joint 58 is connected to the shell through an elastic arm, and the lower end of the secondary actuating joint 57 is connected to the bottom of the shell through a sliding displacement structure; when the eccentric wheel 43 applies tangential pressure to the pressure block, the pressure plate synchronously drives the two secondary actuating joints 57 through the main actuating joint 58 to synchronously apply pressure to the two stacked piezoelectric units 54.

[0046] In this embodiment, a stacked piezoelectric unit 54 group is respectively provided at the four corners of the shell. A stacked piezoelectric unit 54 group includes two stacked piezoelectric units 54 connected in series. An integrated piezoelectric capacitor 55 is connected in series between the two stacked piezoelectric unit 54 groups through a cable 56. The integrated piezoelectric capacitor 55 is used to store the electrical energy converted and output by the stacked piezoelectric unit 54 through piezoelectric excitation under compressive stress actuation.

[0047] See again Figure 2 , where the solid circle represents the eccentric wheel, and the other three dotted circles are the trajectory diagrams of the eccentric wheel in each actuating section.

[0048] In some embodiments, a trigger block 45 is provided on the eccentric wheel 43, and the trigger block 45 is used to apply tangential pressure to the pressure block.

[0049] See Figure 3 The trigger block 45 is a protruding structure or a roller arranged on the side wall of the eccentric wheel 43.

[0050] By using the curved surface of the roller and the pressure block for extrusion, the sliding friction between the eccentric wheel 43 and the pressure block is converted into rolling friction, which can reduce friction and friction noise; the raised structure and the eccentric wheel 43 are connected in a detachable manner. When the raised structure is damaged, the trigger block 45 can be replaced, avoiding the replacement of the eccentric wheel 43 and reducing maintenance costs.

[0051] In some embodiments, the transmission device 4 includes a transmission rod 44 and a base plate 42. With the center of the eccentric wheel 43 as the midpoint, multiple transmission rods 44 are evenly distributed on the eccentric wheel 43. The lower ends of the transmission rods 44 are plugged into the upper surface of the eccentric wheel 43. The base plate 42 is fixed to the upper ends of the multiple transmission rods 44 and is in a horizontal state. The tray rack 2 is fixed on the base plate 42. Multiple sieve plates 31 are located between the tray racks 2 and are stacked. The eccentric wheel 43 rotates through the transmission device to make the tray rack 2 vibrate horizontally, thereby screening the aggregate in the sieve plate 31.

[0052] The plurality of sieve plates 31 are stacked layer by layer from bottom to top, and the sieve holes of the plurality of sieve plates 31 decrease in sequence from top to bottom, and then the aggregate is screened layer by layer according to the different sieve holes to form aggregates of different particle sizes.

[0053] In some embodiments, the pallet rack 2 includes a plurality of support rods 22 and a pressure plate 21; Multiple support rods 22 are set on the base plate 42 and evenly distributed around the circumference. Multiple sieve plates 31 are located between the multiple support rods 22. The pressure plate 2121 is set on the top of the uppermost sieve plate 31. The pressure plate 21 is connected to the support rods 22 by fastening nuts 2323.

[0054] The tray 32 is arranged at the bottom of the lowest sieve plate 31, that is, the bottom of the sieve plate 31 with the smallest sieve holes. The piezoelectric layer is arranged in the tray 32. The piezoelectric sensor 41 is arranged at the center of the base plate 42. The tray 32 is located on the base plate 42. The piezoelectric layer is electrically connected to the piezoelectric sensor 41. During the screening process, the aggregate sieved from the smallest layer of sieve holes falls into the tray 32. The gravity of the falling aggregate produces piezoelectric excitation on the piezoelectric layer. The piezoelectric sensor 41 obtains the waveform signal. The stress piezoelectric excitation generated by the embedding of the aggregate under the action of excitation produces a weak waveform signal. When the lowest sieve plate 31 no longer drops aggregate, the piezoelectric excitation is interrupted, the sensor cannot capture the waveform signal, and no waveform signal is generated within the set time. The controller 11 then determines that this screening experiment is completed and the excitation device 1 stops working.

[0055] The piezoelectric layer is integrated into the bottom of tray 32 and is composed of a piezoelectric material such as piezoelectric ceramics or a flexible PVDF film. Its surface is covered with electrodes and electrically connected to the piezoelectric sensor 41. Tray 32 is located below the smallest mesh opening of the lowest sieve tray 31, directly receiving the sieved aggregate. Its structural design ensures that the aggregate's gravity acts evenly on the surface of the piezoelectric layer. It is also fixed in place by base tray 42, maintaining stable signal transmission with the sensor.

[0056] Based on the positive piezoelectric effect, when the aggregate falls into the tray 32, its gravity causes the piezoelectric layer to deform, and the change in the internal dipole moment produces a weak piezoelectric signal; the piezoelectric sensor 41 monitors the signal characteristics in real time. If there is no new signal indicating that the screening is completed within the set time, the controller 11 will turn off the excitation device 1.

[0057] This intelligently determines the screening endpoint, eliminating errors based on traditional manual experience. The piezoelectric signal directly reflects aggregate dynamics, improving screening accuracy and efficiency. Furthermore, this structure requires no additional energy and, in conjunction with the self-powered system, enhances the device's energy-saving characteristics, making it suitable for automated road engineering testing scenarios.

[0058] In some embodiments, a lighting device is provided on the housing of the excitation device 1 , and the lighting device is connected to the piezoelectric device 5 , and the piezoelectric device 5 supplies energy to the lighting device.

[0059] The lighting device includes a support 24 and a lighting lamp 13 . The support 24 is arranged on the top of the housing. A lamp pole is arranged on the support 24 . The lighting lamp 13 is arranged on the top of the lamp pole. The lighting lamp 13 is connected to the integrated piezoelectric capacitor 55 .

[0060] In some embodiments, a plurality of infrared sensors 12 are arranged in a ring on the top of the shell of the excitation device 1. The infrared sensors 12 are connected to the piezoelectric device 5 and supply power. The infrared sensors 12 emit infrared light vertically upward and are located outside the vibration range of the screen. The infrared sensors 12 are connected to the control unit.

[0061] During the screening process, when a worker's limbs pass through the infrared light sensor and enter the vibration range of the screen, the controller 11 controls the vibration device 1 to stop working to protect the worker.

[0062] The infrared sensor 12 is powered by the electric energy converted by the piezoelectric device 5, and emits an infrared beam vertically upward to form a circular monitoring area outside the vibration range of the screen. When the equipment is running, the control unit receives the infrared signals of each sensor in real time; if a person's limbs or foreign objects enter the monitoring area and block the light beam, the sensor immediately transmits an interruption signal to the control unit, triggering the safety protection mechanism. This design utilizes the linear propagation characteristics of infrared light, combined with a multi-sensor ring layout, to achieve blind-angle monitoring and ensure physical isolation of the vibration working area from the operator. The safety performance of the equipment has been significantly improved: first, active protection can quickly cut off the power and shut down about 0.1-0.3 seconds before a person mistakenly enters the dangerous area, avoiding mechanical damage; second, the ring layout covers the entire circumference of the screen, eliminating monitoring blind spots; in addition, piezoelectric self-powered power reduces additional wiring and enhances system reliability; non-contact detection does not interfere with the screening process, and has strong resistance to dust interference, making it suitable for harsh working conditions.

[0063] In some embodiments, the control unit is disposed on an end surface of the housing, and the control unit includes a controller 11 and a display.

[0064] The working principle of an energy-saving vibration aggregate screening device of the present application is described in detail below.

[0065] According to the requirements of the screening experiment, multiple sieve trays 31 are stacked on the top of the tray 32. The sieve hole diameters of the sieve trays 31 decrease from top to bottom. Aggregate is poured into the topmost sieve tray 31 and sealed and fixed by the pressure plate 21.

[0066] When the power is turned on, the vibration device 1 generates a rotation with a stable frequency, causing the sieve plate 31 to vibrate horizontally. Aggregates are screened under the vibration force, and aggregates of different particle sizes fall into the sieve plates 31 of corresponding mesh sizes, thereby achieving aggregate screening.

[0067] During the screening process, the aggregate sifted out by the bottom sieve plate 31 falls into the tray 32 under the action of gravity. At the same time, the aggregate generates piezoelectric excitation on the piezoelectric layer under the action of gravity, and generates a corresponding piezoelectric waveform signal, which is synchronously captured by the piezoelectric sensor 41 and transmitted to the screening machine display; after a certain period of screening, the bottom sieve plate 31 no longer sieves out aggregate. At this time, the piezoelectric excitation of the piezoelectric layer is interrupted, and the sensor cannot capture the waveform signal. When the piezoelectric excitation interruption time exceeds the set time, the controller 11 outputs a stop command and the screening is completed.

[0068] During the screening process, the eccentric wheel 43 rotates continuously. During the rotation process, the eccentric wheel 43 periodically triggers each piezoelectric device 5 in turn. The rotary force generated by the eccentric wheel 43 is converted into a horizontal tangential force through the actuating section 51 and applied to the stacked piezoelectric unit 54. The stacked piezoelectric unit 54 realizes piezoelectric excitation conversion under stress actuation and stores the output electrical energy into the integrated piezoelectric capacitor 55. The integrated piezoelectric capacitor 55 functions for the lighting lamp 13 and the infrared sensor 12. At the same time, in the power outage state, the integrated piezoelectric capacitor 55 is used to provide auxiliary power to the drive motor to make the excitation device 1 work.

[0069] Infrared sensors 12 are positioned at the four corners of the vibration device 1, surrounding the vibration tray 32. They emit infrared signals vertically upward, creating a spatial barrier for the vibration operation. If a person or foreign object accidentally touches or approaches a vibrating conductive module, the infrared radiation is blocked, and the infrared sensor 12 detects this and initiates an emergency power outage, stopping the machine. When the infrared signal returns to normal, the machine restarts. Example 1

[0070] An energy-saving vibration aggregate screening device, comprising: The excitation device 1 adopts a rectangular shell design, an eccentric wheel 43 driven by a driving motor is arranged inside, and a detachable roller-type trigger block 45 is arranged on the side wall of the eccentric wheel 43.

[0071] A set of piezoelectric devices 5 is installed at each corner of the shell. Each set of piezoelectric devices 5 includes two vertically arranged stacked piezoelectric units 54, an integrated piezoelectric capacitor 55, an actuator 51 with an arc-shaped pressure block, and the arc surface is covered with a 3mm thick fluororubber flexible pad.

[0072] The tray rack 2 includes 4 stainless steel support rods 22 distributed in a 90° circle. 5 layers of standard sieve trays 31 are stacked from top to bottom in the tray rack 2 in descending order of aperture. The bottom tray 32 has a built-in PVDF piezoelectric film layer with a thickness of 0.2 mm. The piezoelectric sensor 41 is embedded in the center of the aluminum alloy base plate 42.

[0073] Pour the aggregate to be screened into the top sieve plate 31 with a pore size of 16 mm, tighten the 304 stainless steel fastening nut 23 of the top pressure plate 21, and the controller 11 presets the screening termination judgment time as 30 seconds without signal.

[0074] The driving motor drives the eccentric wheel 43 to rotate at a speed of 2800 rpm, and the trigger block 45 triggers the stacked piezoelectric unit 54. The single power generation is 15 mJ, and the horizontal amplitude of the sieve plate 31 is controlled at 2±0.1 mm. The bottom sieve plate 31 has an aperture of 0.6 mm and the blanking triggers the piezoelectric layer to generate a 10-100 mV signal.

[0075] The four infrared sensors 1212 form a monitoring plane 50 mm away from the edge of the sieve plate 31. When foreign matter enters the monitoring area, the controller 11 cuts off the power supply within 0.2 seconds. In the power outage state, the energy storage capacitor can keep the entire device working.

[0076] The present application discloses a technical solution for an energy-saving vibration aggregate screening device. First, its intelligent control system uses a piezoelectric layer and a piezoelectric sensor 41 to monitor the aggregate sieving status in real time, accurately determining the screening endpoint and automatically shutting down the device. This completely solves the problems of insufficient screening or time redundancy caused by traditional methods relying on manual experience, significantly improving the accuracy and consistency of screening tests. Second, the device innovatively adopts an energy recovery design, converting the mechanical energy generated by the rotation of the eccentric wheel 43 into electrical energy through the piezoelectric device 5. This not only enables the device to be self-powered, reducing external energy consumption, but also provides power for auxiliary equipment such as lighting and sensors, significantly improving energy utilization efficiency. In addition, the device adopts a highly integrated solution, organically combining the vibration device 1, the piezoelectric power generation module, and the screening tray 32, resulting in a compact structure and easy maintenance. Finally, the device is equipped with an infrared sensor 12 and an emergency power-off function, which can promptly detect human approach and automatically shut down the device, effectively ensuring operational safety. In addition, the combination of flexible connectors and an intelligent control system reduces mechanical wear and extends the service life of the equipment, while also avoiding excessive aggregate crushing and ensuring the accuracy of test data. The device also boasts strong environmental adaptability, with its self-powered system enabling it to maintain normal operation in unstable power conditions or in the wild, significantly expanding its application scenarios. Through its mechatronic design, the device achieves comprehensive optimization in screening efficiency, energy utilization, operational safety, and equipment reliability, providing an efficient, precise, and environmentally friendly solution for aggregate screening in road construction projects, with broad market application prospects and promotional value.

[0077] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. An energy-saving vibration aggregate screening device, characterized in that: It includes a vibration device, a piezoelectric device and a piezoelectric tray; The excitation device includes a housing and an eccentric wheel disposed inside the housing. A plurality of piezoelectric devices are disposed in the housing and are located on the rotation trajectory of the eccentric wheel. The eccentric wheel can apply compressive stress to the piezoelectric devices during rotation, and the piezoelectric devices convert and output electrical energy through piezoelectric excitation. The piezoelectric tray includes a tray frame, a sieve tray, a tray, a piezoelectric layer and a piezoelectric sensor; The tray frame is connected to the eccentric wheel through a conducting device, and a plurality of sieve plates are stacked on the tray frame from top to bottom. The tray is arranged at the bottom of the lowest sieve plate, and the piezoelectric layer is arranged in the tray. The piezoelectric layer generates a piezoelectric excitation signal under the gravity of the aggregate sieved by the lowest sieve plate, and the piezoelectric layer is connected to the piezoelectric sensor; The vibration excitation device and the piezoelectric sensor are respectively connected to a control unit. The control unit determines the screening completion time according to the piezoelectric excitation signal and controls the operation of the vibration excitation device.

2. The energy-saving vibration aggregate screening device according to claim 1, characterized in that: The piezoelectric device includes a stacked piezoelectric unit, an actuator and a pressure block; The stacked piezoelectric unit is fixed on the side wall of the shell, and the bottom of the actuating section is connected to the shell through a displacement structure. One end of the actuating section is used to apply pressure to the stacked piezoelectric unit, and the other end of the actuating section is connected to the pressure block, which is located on the rotation track of the eccentric wheel.

3. The energy-saving vibration aggregate screening device according to claim 2, characterized in that: An insulating actuating gasket is provided on one side of the pressure plate close to the stacked piezoelectric unit, and a side of the pressure block close to the eccentric wheel is an arc-shaped surface, the curvature of the arc-shaped surface is smaller than the curvature of the circular track of the eccentric wheel.

4. The energy-saving vibration aggregate screening device according to claim 2, characterized in that: The displacement structure is an elastic displacement structure or a sliding displacement structure.

5. The energy-saving vibration aggregate screening device according to claim 2, characterized in that: Stacked piezoelectric units are respectively provided on both sides of the corners of the shell; The transmission joint includes a main actuating joint and a secondary actuating joint, one end of the two secondary actuating joints is connected to the two pressure plates respectively, and the other ends of the two secondary actuating joints are connected to the pressure block. The main actuating joint is located on the midline between the angles of the two secondary actuating joints, one end of the main actuating joint is connected to the ends of the two pressure plates close to each other through a connecting arm, and the other end of the main actuating joint is connected to the middle of the pressure block.

6. The energy-saving vibration aggregate screening device according to claim 1, characterized in that: The eccentric wheel is provided with a trigger block, which is used to apply tangential pressure to the pressure block; The trigger block is a protruding structure or a roller arranged on the side wall of the eccentric wheel.

7. The energy-saving vibration aggregate screening device according to claim 1, characterized in that: The transmission device includes a transmission rod and a base plate. With the center of the eccentric wheel as the midpoint, multiple transmission rods are evenly distributed on the eccentric wheel. The transmission base plate is fixed to the upper ends of the multiple transmission rods and is in a horizontal state. The tray rack is fixed on the base plate.

8. The energy-saving vibration aggregate screening device according to claim 7, characterized in that: The piezoelectric layer is arranged in the tray, the piezoelectric sensor is fixed on the base tray, and the piezoelectric layer is pressed onto the piezoelectric sensor and is electrically conductive.

9. The energy-saving vibration aggregate screening device according to claim 1, characterized in that: The sieve holes of the plurality of sieve plates decrease in size from top to bottom.

10. The energy-saving vibration aggregate screening device according to claim 1, characterized in that: A plurality of infrared sensors are arranged in a ring on the top of the shell of the excitation device. The infrared sensors are connected to the piezoelectric device. The infrared sensors emit infrared light vertically upward and are located outside the vibration range of the screen. The infrared sensors are connected to the control unit.

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