Linear vibration screening device and method with actively adjustable amplitude

Abstract

The present invention provides a linear vibration screening device and method for actively adjusting the amplitude, which includes a power input module, an amplitude adjustment module, a connecting rod mechanism and a vibrating screen. The power input module drives the vibrating screen to work through the connecting rod mechanism; the power input module includes an output turntable and a linear groove, and the amplitude adjustment module includes an adjustment turntable and an arc groove; a connecting shaft is arranged at the driving end of the connecting rod mechanism, and both ends of the connecting shaft are respectively nested in the linear groove and the arc groove, and the other end of the connecting rod drives the screen surface assembly of the vibrating screen; the arc groove is designed according to a curve shape with a specific law relative to the axis of the adjustment turntable, so that the distance of the connecting shaft relative to the rotation axis can be calculated in association with the change of the angle difference between the adjustment turntable and the output turntable, making it possible to accurately adjust the amplitude online, and finally ensuring that the running speed of the vibrating screen meets the constraints and improving the screening efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration screening, and specifically, to a linear vibration screening device with actively adjustable amplitude and its method. Background Art

[0002] Linear vibration screening systems are widely used in occasions of material screening, and their screening results can be applied to material structure detection, etc. The screening efficiency of materials is greatly affected by the amplitude and frequency of the movement of the sieve mesh. How to improve the screening efficiency has always been the focus of research by scholars.

[0003] Improving the passing rate of materials through the sieve mesh and further enhancing the screening efficiency are crucial for vibration screening devices. Some patents design vibration screening devices with multiple degrees of freedom to improve the passing rate and screening efficiency. Chinese Patent No. 2019102224813 discloses a three-degree-of-freedom hybrid vibration screening mechanism, control method, and harvester, which can monitor the grain loss rate and its distribution state in real time, and adaptively optimize and adjust the horizontal attitude angle of the sieve surface, the inclination angle of the sieve surface, and the vibration frequency to improve the screening efficiency under the condition of non-uniform feeding of materials. Chinese Patent No. 201810023726.5 discloses a double-layer multi-degree-of-freedom vibration screening device, and through the semi-automatic transfer of materials, high-efficiency screening is achieved, greatly improving the screening efficiency, reducing the working time, and facilitating large-scale industrial production.

[0004] For a vibration screening system, the relative movement speed of the material with respect to the sieve mesh restricts the passing rate and screening efficiency, and both the vibration amplitude and frequency of the sieve mesh affect the relative movement speed. The change in frequency is generally achieved by adjusting the motor movement frequency. For example, Chinese Patent No. 202110007867.X discloses a vibration screening machine, and the invention controller can control the oscillation frequency of the vibrating screen, effectively improving the screening efficiency and the degree of automation of material forward movement and transportation. However, the change in vibration frequency will have a greater impact on the productivity of the screening system.

[0005] The adjustment of the amplitude is achieved by changing the structural parameters or dynamic characteristics. By changing the structural parameters, the amplitude at different positions of the sieve mesh can be adjusted, thereby improving the state of material accumulation at different positions of the sieve mesh. For example, in the Chinese doctoral dissertation "Research on the Screening Process with Variable Amplitude to Prevent Blockage under Different Feeding Modes", the vibration screening device involved adjusts the parameters of the connecting rod to change the amplitude and other parameters at different positions of the sieve surface; in the Chinese doctoral dissertation "Research on the Mechanism of Variable Amplitude Equal Thickness Elastic Deep Screening of Wet Coal", the variable amplitude vibration screening device involved is achieved by changing the material separation curve of different segmented sieve surfaces. However, the above-mentioned documents are all cases where the structural parameters are fixed and the amplitude parameters are also fixed. Currently, there is little research on actively and real-time adjusting the amplitude. For the method of adjusting dynamic characteristics, such as a non-linear vibration relaxation screen amplitude online stepless adjustment device and its use method in Chinese Patent CN114273219B, and a high-frequency screen with automatic amplitude adjustment and its automatic adjustment method in CN105855160B, the amplitude is adjusted by adding a stepless adjustment damper device or adjusting the magnitude of the current respectively. However, this method relies on a dynamic model and does not have the ability to observe the amplitude in real time, and cannot accurately control the amplitude of the vibration screening system.

[0006] For a linear vibration screening system, in order to improve the amplitude control accuracy, the method of adjusting the structural parameters of the vibration system is often used to achieve the adjustment of the amplitude. The difficulty in adjusting the amplitude online and in real time lies in how to design the structural parameter adjustment mechanism of the vibration mechanism to achieve precise control of the amplitude. The adjustment of the amplitude usually requires adjusting the effective action length of the swing arm, and the swing arm moves at a high frequency together with the load. If the mechanism for adjusting the amplitude is loaded at the load end, it may cause the load to be overloaded and affect the overall efficiency and stability.

[0007] And in more in-depth research, it is found that the screening efficiency of the material in the linear vibrating screen is directly determined by the passing rate of the material through the sieve. If the movement speed of the sieve surface is too large, the passing rate will decrease; if the movement speed is too small, the friction between the material and the sieve surface will hinder the relative movement between the material and the sieve surface. To improve the passing effect of the material, the movement speed of the sieve surface should be limited within a suitable range, and the autonomous adjustment of the amplitude is an effective way to solve this problem.

[0008] Therefore, how to achieve real-time control of the vibration amplitude during the vibration screening process, so as to ensure that the movement speed of the vibrating screen is as far as possible within the constrained range, improve the passing rate and screening efficiency of the material, and do not affect the bearing capacity of the load end, is an urgent problem to be solved.

[0009] In order to solve the above existing problems, people have been seeking an ideal technical solution. Summary of the Invention

[0010] The object of the present invention is to address the deficiencies of the prior art, and thus provide a linear vibration screening device and method for actively adjusting the amplitude. The precise control of the amplitude is achieved by the form of two motors respectively driving the load and the adjusting mechanism. At the same time, the adjusting mechanism has no influence on the bearing capacity of the load end, ensuring the vibration screening efficiency.

[0011] The basic design concept of the present invention lies in: the movement speed of the screen of the linear vibration screening device is designed in linkage with the screen amplitude to form an adjustment model. At the same time, by designing the law of amplitude adjustment, the amplitude adjustment range is associated with the difference in the movement output angles of the two motors. Finally, through the control of the movement angles at the output ends of the two motors, the adjustment of the amplitude is realized, and then the adjustment of the movement speed of the screen is realized, effectively improving the passing rate. The present invention has no influence on other vibration parameters, avoiding the traditional single motor from frequently accelerating and decelerating to improve the passing rate, which affects the vibration frequency of the screen and thus the productivity of the screening system.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is: a linear vibration screening device for actively adjusting the amplitude, characterized in that: it includes a power input module, an amplitude adjustment module, a connecting rod mechanism and a vibrating screen, and the power input module drives the vibrating screen to work through the connecting rod mechanism;

[0013] The power input module includes an output turntable that actively makes a rotary motion and a linear groove provided on the output turntable. The amplitude adjustment module includes an adjustment turntable that actively makes a rotary motion and an arc groove provided at an eccentric position of the adjustment turntable. The rotation axes of the output turntable and the adjustment turntable are on the same rotation axis line;

[0014] A connecting shaft is provided at the driving end of the connecting rod mechanism. The two ends of the connecting shaft are respectively nested in the linear groove and the arc groove with a clearance fit, and the other end of the connecting rod drives the screen assembly of the vibrating screen.

[0015] The arc groove is designed in a curve shape with a specific law relative to the axis of the adjustment turntable. The linear groove is designed in a specific direction. The relative rotation of the adjustment turntable and the output turntable is used to adjust the distance between the connecting shaft and the rotation axis. The synchronous rotation of the adjustment turntable and the output turntable is used to drive the operation of the connecting rod mechanism. The distance between the connecting shaft and the rotation axis can be calculated in association with the change in the angle difference between the adjustment turntable and the output turntable.

[0016] Based on the above, the connecting rod mechanism includes a connecting rod, a bearing, the connecting shaft and a bushing. The bushing is a self-lubricating graphite bronze bushing. The driving end of the connecting rod is installed on the connecting shaft through a bearing. Two bushings are respectively installed at the two ends of the connecting shaft. The two bushings are respectively nested in the linear groove and the arc groove with a clearance fit, and the other end of the connecting rod drives the screen assembly of the vibrating screen through a bearing.

[0017] Based on the above, the curve with specific rules is a Bessel curve, a sine curve, or a cosine curve.

[0018] Based on the above, the output turntable and the adjustment turntable are respectively driven by two motors. The two motors are installed on the same platform and rotate at the same speed under normal conditions and at different speeds under speed adjustment conditions.

[0019] Based on the above, the motor of the power input module is fixed to the platform through the first bracket. The output turntable is installed on the output shaft of the motor of the power input module. The output turntable and the first bracket are rotationally matched through a first crossed roller bearing, and a first inner pressure plate covering the first crossed roller bearing is installed at the outer end of the first bracket.

[0020] Based on the above, the motor of the amplitude adjustment module is fixed to the platform through the second bracket. The adjustment turntable is installed on the output shaft of the motor of the amplitude adjustment module. The adjustment turntable and the second bracket are rotationally matched through a second crossed roller bearing, and a second inner pressure plate covering the second crossed roller bearing is installed at the outer end of the second bracket.

[0021] Based on the above, the vibrating screen is a linear vibrating screen, including a screen mesh, a guide rail mechanism, and a support frame. The screen mesh moves linearly back and forth along the guide rail mechanism under the drive of a connecting rod, and the screen mesh and the guide rail mechanism are installed on the platform based on the support frame.

[0022] Based on the above, the output turntable outputs an angle θ 1 , and the adjustment turntable outputs an angle θ 2 . It is determined that the curve with specific rules is a Bessel curve. x r represents the movement displacement of the screen mesh, represents the movement speed of the screen mesh, h represents the height between the screen mesh and the rotation center of the power input module, which is a fixed value, and l 1 represents the distance between the rotation center of the power input module and the connecting shaft of the connecting rod mechanism, which is an adjustable quantity. l 2 represents the distance between the rotation centers at both ends of the connecting rod, which is a fixed value. The distance l between the rotation center of the power input module and the connecting shaft 1 is expressed as:

[0023] l 1 = f(θ 2 - θ 1 )

[0024] where the function f represents the mapping relationship between the angular difference θ 2 - θ 1 and l 1 and is determined by the Bessel curve mathematical expression of the arc groove.

[0025] A linear vibration screening method for actively adjusting the amplitude, including the linear vibration screening device for actively adjusting the amplitude and an amplitude adjustment controller, where the amplitude adjustment controller is used to control the operating states of the motors of the power input module and the amplitude adjustment module, and the adjustment is performed by the following method:

[0026] According to the screen parameters, establish a motion model of the vibration screening system and determine the motion displacement x of the screen r and the mathematical relationship expression of the motion speed ;

[0027] According to the material and screen parameters, establish a material passing-through-screen model and determine the maximum speed of the screen when the material passes through the screen

[0028] When the motion speed of the screen is within the constrained speed range, that is , control the two motors to move synchronously at the set rotational speed, and the change rate of the distance between the connecting shaft and the rotation center of the power input module and make the output angles θ 1 and θ 2 of the two motors keep in sync, that is

[0029] When the motion speed of the screen is greater than the constrained maximum speed, that is , control the motor of the power input module to continue to move at the set rotational speed , and generate a rotational speed difference between the output angle θ 2 and θ 1 of the motor of the amplitude adjustment module through the amplitude adjustment controller, so that the arc groove of the adjustment turntable cooperates with the linear groove on the output turntable to adjust the radial position of the connecting shaft in real time, that is, the distance l 1 between the connecting shaft and the rotation center of the power input module, and keep the motion speed of the screen within the constrained speed range through the adjustment of the amplitude.

[0030] Based on the above, when the motion speed of the screen is greater than the constrained maximum speed, that is , the expected adjustment law of the distance l 1 from the rotation center of the power input module to the connecting shaft is expressed as:

[0031]

[0032] where t i+1 =t i +Δt, t is time, and Δt is the sampling interval.

[0033] Based on the above, the control adjustment law of the output angle θ 2 of the motor of the amplitude adjustment module is expressed as:

[0034] θ 2 = f -1 (l 1 ) + θ 1

[0035] wherein, the function f -1 represents the inverse function of the function f(θ 2 - θ 1 ).

[0036] Based on the above, the control target of the amplitude adjustment controller is designed to: maximize the control of the movement speed of the sieve mesh within the speed constraint range.

[0037] The present invention has prominent substantial features and remarkable progress compared with the prior art. Specifically, the present invention has the following advantages:

[0038] 1. The present invention designs a linear vibrating screening system that adjusts based on the correlation between the vibration speed and amplitude of the sieve mesh, thereby improving the passing rate. Among them, the adjustment of the amplitude is precise. The designed adjustment method includes an adjustment mechanism composed of two turntables and arc grooves with specific curves and linear grooves in specific directions respectively arranged on the turntables. The adjustment of the amplitude can be adjusted by changing the rotation angles of the two turntables. The adjustment process of the amplitude has a calculation formula to follow, can be parameterized, and can be actively intervened and adjusted online only by adjusting the rotation speeds of two driving motors, which is efficient and convenient.

[0039] 2. In the high-frequency vibration mode, the link mechanisms for determining the amplitude are all located at the load end. If the adjustment mechanisms are all arranged at the load end, it will cause the load at the load end to be too heavy, which is not conducive to vibration generation; and the power required to change the amplitude is extremely large, and it is also difficult to design it at the load end. Therefore, in this case, two motors are used to drive the adjustment turntable and the output turntable respectively. Through the synchronous rotation of the two, the consistency of the output is achieved, and through differential adjustment, the adjustment of the amplitude is achieved. This method can, on the one hand, avoid high loads at the load end, and on the other hand, can provide a large external force required during the adjustment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is the overall structural schematic diagram of the linear vibrating screening device for actively adjusting the amplitude in the present invention.

[0041] Figure 2 is the exploded structural schematic diagram of the core transmission part of the linear vibrating screening device for actively adjusting the amplitude in the present invention.

[0042] Figure 3 is the cross-sectional view of the core transmission part of the linear vibrating screening device for actively adjusting the amplitude in the present invention.

[0043] Figure 4 It is the schematic diagram of amplitude adjustment principle in the present invention.

[0044] Figure 5 It is the schematic diagram of linear vibration screening motion modeling in the present invention.

[0045] Figure 6 It is the schematic diagram of linear vibration screening method in the present invention.

[0046] Figure 7 It is the schematic diagram of material passing through the screen of the vibration screening device in the present invention.

[0047] Figure 8 It is the simulation of the screen motion speed of the vibration screening device in the present invention.

[0048] In the figure: 1. Power input module; 2. Amplitude adjustment module; 3. Linkage mechanism; 4. Vibration screen; 5. Platform;

[0049] 11. First motor; 12. Output turntable; 13. Linear groove; 14. First bracket; 15. First crossed roller bearing; 16. First inner pressure plate;

[0050] 21. Second motor; 22. Adjustment turntable; 23. Arc groove; 24. Second bracket; 25. Second crossed roller bearing; 26. Second inner pressure plate;

[0051] 31. Link; 32. Bearing; 33. Connecting shaft; 34. Bushing;

[0052] 41. Screen; 42. Guide rail mechanism; 43. Support frame. Detailed implementation manners

[0053] The technical solution of the present invention will be further described in detail below through specific implementation manners.

[0054] As Figures 1-8 shown, a linear vibration screening device for actively adjusting the amplitude includes a power input module 1, an amplitude adjustment module 2, a linkage mechanism 3 and a vibration screen 4, and the power input module 1 drives the vibration screen 4 to work through the linkage mechanism 3.

[0055] The power input module 1 includes a first motor 11, an output turntable 12 driven by the first motor 11 to perform a rotary motion, and a linear groove 13 provided on the output turntable 12. In this embodiment, the orientation of the linear groove 13 passes through the axis of the output turntable 12, and the power input module 1 provides the main output power. Specifically, the first motor 11 is fixed to the platform 5 through a first bracket 14, the output turntable 12 is installed on the output shaft of the first motor 11, the output turntable 12 and the first bracket 14 are rotationally matched through a first crossed roller bearing 15, and a first inner pressure plate 16 covering the first crossed roller bearing 15 is installed at the outer end of the first bracket 14.

[0056] The amplitude adjustment module 2 includes a second motor 21, an adjustment turntable 22 driven by the second motor 21 to perform a rotary motion, and an arc groove 23 provided at an eccentric position of the adjustment turntable 22. In this embodiment, the curve form of the arc groove 23 is a Bezier curve set based on the axis of the adjustment turntable 22 as a reference. Specifically, the second motor 21 is fixed to the platform 5 through a second bracket 24, the adjustment turntable 22 is installed on the output shaft of the second motor 21, the adjustment turntable 22 and the second bracket 24 are rotationally matched through a second crossed roller bearing 25, and a second inner pressure plate 26 covering the second crossed roller bearing 25 is installed at the outer end of the second bracket 24.

[0057] The rotation axes of the output turntable 12 and the adjustment turntable 22 are located on the same rotation axis line. The two motors are installed based on the same platform, and the two motors rotate at the same speed in the normal state and at different speeds in the speed adjustment state. Specifically, when the motion angles output by the first motor and the second motor are inconsistent, the arc groove 23 in the adjustment turntable 22 drives the connecting shaft 33 to move along the linear groove 13, that is, move along the rotation axis, and change the distance between the connecting shaft and the rotation axis, thereby realizing the real-time adjustment of the amplitude.

[0058] The connecting rod mechanism 3 includes a connecting rod 31, a bearing 32, a connecting shaft 33, and a bushing 34. The bushing 34 is selected as a self-lubricating graphite bronze bushing. The driving end of the connecting rod 31 is installed on the connecting shaft 33 through the bearing 32. Two bushings 34 are respectively installed at both ends of the connecting shaft 33, and the two bushings 34 are respectively nested in the linear groove 13 and the arc groove 23 with a clearance fit. The other end of the connecting rod 31 drives the screen surface assembly of the vibrating screen 4 through the bearing 32.

[0059] The vibrating screen 4 is a linear vibrating screen, including a screen mesh 41, a guide rail mechanism 42, and a support frame 43. The screen mesh 41 reciprocates linearly along the guide rail mechanism 42 under the drive of the connecting rod 31, and the screen mesh 41 and the guide rail mechanism 42 are installed on the platform 5 based on the support frame 43.

[0060] In actual driving work, the amplitude of the link mechanism 3 needs to be determined by adjusting the turntable 22 and the output turntable 12 together. Therefore, when the rotational speeds of the first motor 21 and the second motor 22 are synchronized, the amplitude is fixed. The output power at the load end requires the joint output of the first motor 21 and the second motor 22. However, the main function of the first motor 21 is power output, and the main function of the second motor 22 is for adjustment.

[0061] The basic principle of adjustment is that the arc groove 23 is designed in the shape of a Bézier curve relative to the axis of the adjustment turntable 22, so that the change in the distance between the driving end of the link mechanism 3 and the axis of the adjustment turntable or the output turntable can be calculated in relation to the rotational angle of the adjustment turntable.

[0062] Specifically, a linear vibration screening method for actively adjusting the amplitude is designed, including the linear vibration screening device for actively adjusting the amplitude and the amplitude adjustment controller. The amplitude adjustment controller is used to control the working states of the motors of the power input module and the amplitude adjustment module, and the adjustment is carried out by the following method:

[0063] S1: According to the vibration screening structure parameters, a motion model of the vibration screening system is established. The motion displacement and velocity of the screen surface of the vibration screening system can be expressed as:

[0064]

[0065] Among them, the output angle θ of the output turntable 1 , the output angle θ of the adjustment turntable 2 , x r represents the motion displacement of the screen mesh, represents the motion velocity of the screen mesh, h represents the height between the screen mesh and the rotation center of the power input module (the axis of the output turntable), which is a fixed value, l 1 represents the distance between the rotation center of the power input module (the axis of the output turntable) and the connecting shaft of the link mechanism, which is an adjustable quantity, l 2 represents the distance between the rotation centers at both ends of the link, which is a fixed value.

[0066] S2: According to the material and screen mesh parameters, a material passing-through-screen model is established to determine the maximum velocity of the screen mesh under the condition of material passing through the screen

[0067] Taking the relative velocity between the material and the screen mesh at the critical passing-through-screen as the constraint condition, the maximum velocity of the screen mesh Taking the ellipsoidal material particles as an example, the critical motion equation for their relative downward oblique throwing motion is:

[0068]

[0069] Among them, ΔX and ΔY are the horizontal and vertical components during the process of the particle being obliquely thrown through the sieve, D is the equivalent sieve hole diameter, and a and d are the short diameter and long diameter of the ellipsoidal material particle;

[0070] The critical velocity is calculated as follows:

[0071]

[0072] S3: When the moving speed of the sieve mesh is within the constrained speed range, that is, control the first motor and the second motor to move at the set rotational speed, and make the output angles θ 1 and θ 2 increments remain synchronized,

[0073] S4: When the moving speed of the sieve mesh is greater than the maximum constrained speed, that is, control the first motor to continue moving at the set rotational speed design an amplitude adjustment controller to control the second motor to cause a rotational speed difference between the output angles θ 2 and θ 1 so as to adjust the radial position of the connecting shaft in the link mechanism in real time by adjusting the arc groove in the turntable, and further adjust the position of the connecting shaft in the straight groove in the power drive disc, and keep the moving speed of the sieve mesh within the constrained speed range through the adjustment of the amplitude.

[0074] Specifically as follows:

[0075] The distance l from the center of rotation (axis of rotation) to the connecting shaft 1 is expressed as:

[0076]

[0077] Among them, t i+1 = t i +Δt, where t is time and Δt is the sampling interval.

[0078] It should be noted that the moving speed of the sieve mesh can be monitored by a conventional sensor, and the monitoring data is shared with the amplitude adjustment controller in real time.

[0079] The motor output angle θ 2 of the amplitude adjustment module is controlled by the adjustment law expressed as:

[0080] θ 2 = f -1 (l 1 ) + θ 1

[0081] Among them, the function f-1 represents the inverse function of the function f(θ 2 -θ 1 ).

[0082] The distance l between the rotation center of the power input module and the connecting shaft 1 is expressed as:

[0083] l 1 = f(θ 2 -θ 1 )

[0084] where the function f represents the mapping relationship between the rotation angle difference θ 2 -θ 1 and l 1 , which is determined by the Bessel curve mathematical expression of the arc groove.

[0085] In other embodiments, the curve design of the arc groove can also be other forms of curves, such as sine or cosine curves, etc. Any curve that can be quantified by calculation can be used.

[0086] The control objective of the amplitude adjustment controller is designed to: maximize the control of the movement speed of the sieve mesh within the speed constraint range, so as to improve the material passing rate and screening efficiency of the sieve mesh, and avoid the frequent acceleration and deceleration of the traditional single motor to improve the passing rate, which affects the vibration frequency of the sieve mesh and further affects the productivity of the screening system.

[0087] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A linear vibration screening device with actively adjustable amplitude, characterized in that: it includes a power input module, an amplitude adjustment module, a connecting rod mechanism and a vibrating screen, and the power input module drives the vibrating screen to work through the connecting rod mechanism; the power input module includes an output turntable that actively makes a rotary motion and a linear groove provided on the output turntable, the amplitude adjustment module includes an adjustment turntable that actively makes a rotary motion and an arc groove provided at an eccentric position of the adjustment turntable, and the rotation axes of the output turntable and the adjustment turntable are on the same rotation axis line; a connecting shaft is provided at the driving end of the connecting rod mechanism, and both ends of the connecting shaft are nested in the linear groove and the arc groove respectively with clearance fit, and the other end of the connecting rod mechanism drives the screen surface assembly of the vibrating screen; the arc groove is designed in a curve shape with a specific law relative to the axis of the adjustment turntable, and the specific law curve is a Bezier curve or a sine curve or a cosine curve; the linear groove is designed in a specific direction, and the specific direction refers to the direction in which the linear groove faces the direction passing through the axis of the output turntable. The relative rotation of the adjustment turntable and the output turntable is used to adjust the distance between the connecting shaft and the rotation axis, the synchronous rotation of the adjustment turntable and the output turntable is used to drive the operation of the connecting rod mechanism, and the distance between the connecting shaft and the rotation axis can be calculated in association with the change in the angle difference between the adjustment turntable and the output turntable.

2. The linear vibration screening device with actively adjustable amplitude according to claim 1, characterized in that: the connecting rod mechanism includes a connecting rod, a bearing, the connecting shaft and a bushing, the bushing is a self-lubricating graphite bronze bushing, the driving end of the connecting rod is installed on the connecting shaft through a bearing, both ends of the connecting shaft are respectively installed with two bushings, and the two bushings are respectively nested in the linear groove and the arc groove with clearance fit, and the other end of the connecting rod drives the screen surface assembly of the vibrating screen through a bearing.

3. The linear vibration screening device with actively adjustable amplitude according to claim 2, characterized in that: the output turntable and the adjustment turntable are respectively driven by two motors, the two motors are installed based on the same platform, and the two motors rotate at the same speed in the normal state and rotate at different speeds in the speed adjustment state.

4. The linear vibration screening device with actively adjustable amplitude according to claim 3, characterized in that: the motor of the power input module is fixed on the platform through a first bracket, the output turntable is installed on the output shaft of the motor of the power input module, and the output turntable and the first bracket are rotationally matched through a first crossed roller bearing, and a first inner pressure plate covering the first crossed roller bearing is installed at the outer end of the first bracket.

5. The linear vibration screening device with actively adjustable amplitude according to claim 4, characterized in that: the motor of the amplitude adjustment module is fixed on the platform through a second bracket, the adjustment turntable is installed on the output shaft of the motor of the amplitude adjustment module, and the adjustment turntable and the second bracket are rotationally matched through a second crossed roller bearing, and a second inner pressure plate covering the second crossed roller bearing is installed at the outer end of the second bracket.

6. The linear vibration screening device with actively adjustable amplitude according to claim 3 or 4 or 5, characterized in that: The vibrating screen is a linear vibrating screen, which includes a screen mesh, a guide rail mechanism and a support frame. The screen mesh moves linearly back and forth along the guide rail mechanism under the drive of a connecting rod, and the screen mesh and the guide rail mechanism are installed on the platform based on the support frame.

7. The linear vibrating screening device with actively adjustable amplitude according to claim 6, characterized in that: The output turntable outputs an angle θ 1 , the adjustment turntable outputs an angle θ 2 , determining that the curve of the specific law is a Bezier curve, x r represents the movement displacement of the sieve, represents the movement speed of the sieve, h represents the height between the sieve and the rotation center of the power input module, which is a fixed value, l 1 represents the distance between the rotation center of the power input module and the connecting shaft of the linkage mechanism, which is an adjustable quantity, l 2 represents the distance between the rotation centers at both ends of the connecting rod, which is a fixed value, and the distance l between the rotation center of the power input module and the connecting shaft 1 is expressed as: l 1 = f(θ 2 - θ 1 ) Among them, the function f represents the mapping relationship between the rotation angle difference θ 2 -θ 1 and l 1 which is determined by the mathematical expression of the Bezier curve of the arc groove.

8. A linear vibrating screening method with actively adjustable amplitude, characterized in that: comprises the linear vibrating screening device with actively adjustable amplitude according to claim 7 and an amplitude adjustment controller. The amplitude adjustment controller is used to control the working states of the motors of the power input module and the amplitude adjustment module, and the adjustment is carried out by the following method: According to the vibrating screen parameters, establish the motion model of the vibrating screening system and determine the mathematical relationship expression of the motion displacement x r and the motion speed of the mathematical relationship expression; Establish a material passing-through sieve model according to the material and sieve parameters, and determine the maximum speed of the sieve when the material passes through the sieve When the moving speed of the sieve mesh is within the constrained speed range, that is , control the two motors to move synchronously at the set rotational speeds, and the change rate of the distance between the connecting shaft and the rotational center of the power input module and make the output angle increments θ 1 and θ 2 remain synchronous, that is When the moving speed of the sieve mesh is greater than the maximum speed of the constraint, that is , control the motor of the power input module to continue to move at the set rotational speed , and generate a rotational speed difference between the output angle θ 2 of the motor of the amplitude adjustment module controlled by the amplitude adjustment controller and θ 1 , so that the arc groove of the adjustment turntable cooperates with the straight groove on the output turntable to adjust the radial position of the connecting shaft in real time, that is, the distance l 1 between the connecting shaft and the rotation center of the power input module. By adjusting the amplitude, the moving speed of the sieve mesh is kept within the constraint speed range.

9. The linear vibrating screening method with actively adjustable amplitude according to claim 8, characterized in that: When the moving speed of the screen mesh is greater than the maximum speed of the constraint, that is At this time, the distance l between the rotation center of the power input module and the connecting shaft 1 The desired adjustment law is expressed as: where t i+1 = t i + Δt, where t is time and Δt is the sampling interval.

10. The linear vibrating screening method with actively adjustable amplitude according to claim 9, characterized in that: The motor output angle θ of the amplitude adjustment module described above 2 The control adjustment law is expressed as: θ 2 = f -1 (l 1 ) + θ 1 Among them, the function f -1 represents the inverse function of the function f(θ 2 - θ 1 ).

11. The linear vibrating screening method with actively adjustable amplitude according to claim 9, characterized in that: the control target of the amplitude adjustment controller is designed to: control the movement speed of the screen mesh to be kept within the speed constraint range to the greatest extent.

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