Elastic supporting assembly for vibrating screen and rigidity adjusting method of elastic supporting assembly

Abstract

The invention provides an elastic supporting assembly for a vibrating screen and a rigidity adjusting method thereof, and relates to the field of vibrating screens, the elastic supporting assembly comprises a bottom plate, a pre-tightening plate, an elastic system, a mounting frame and a pre-tightening bolt; the pre-tightening plate is horizontally located above the bottom plate, and the mounting frame is provided with a mounting plate located between the pre-tightening plate and the bottom plate. The pre-tightening bolt movably penetrates through the bottom plate, the mounting plate and the pre-tightening plate in sequence from bottom to top and can be connected and adjusted through a nut; the elastic system comprises a first disc spring set, a second disc spring set, a first electromagnetic set and a second electromagnetic set, the first disc spring set is located between the pre-tightening plate and the mounting plate, the second disc spring set is located between the mounting plate and the bottom plate, the first electromagnetic set is located between the first disc spring set and the pre-tightening plate, and the second electromagnetic set is located between the second disc spring set and the bottom plate. The rigidity of the whole elastic supporting system can be changed, it can be guaranteed that the frequency and amplitude of the disc spring vibrating screen are kept constant during working, and the stability of the disc spring vibrating screen is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vibrating screen, in particular to an elastic support assembly for vibrating screen and a stiffness adjusting method thereof. BACKGROUND

[0002] The traditional elliptical vibrating screen is widely used in sand and mining industry due to its simple structure, easy operation and daily maintenance. With the development of large-scale and high-speed vibrating screen, the traditional elliptical vibrating screen cannot meet the stable working state due to the need for greater exciting force, which is contrary to the concept of green environmental protection and energy saving and emission reduction advocated by the country. Greater exciting force also accelerates the fatigue damage of parts and reduces the service life of the vibrating screen. To solve the problem of excessive exciting force of large-scale vibrating screen, disc spring elastic vibrating screen emerges as the times require. It uses the principle of linear resonance to amplify the amplitude of the screen body, solves the problem that the traditional inertial vibrating screen cannot use resonance principle to improve the amplitude due to low stiffness of spiral spring, and has better working stability and equipment reliability compared with the resonance screen using nonlinear spring.

[0003] The successful development of disc spring elastic vibrating screen to some extent solves the problem of excessive exciting force demand in the large-scale vibrating screen in China, but the stiffness of the disc spring elastic vibrating screen is fixed. When the load mass on the spring changes, the best resonance frequency of the screen body also changes, resulting in unstable working state of the vibrating screen and reducing the screening performance of the vibrating screen. SUMMARY

[0004] Therefore, the present application discloses an elastic support assembly for vibrating screen and a stiffness adjusting method thereof, which can adjust the stiffness of the screen body according to the change of the load on the spring, so as to adjust the natural frequency of the vibrating screen to be consistent with the working frequency, and ensure the best working state.

[0005] In the first aspect, the present application provides an elastic support assembly for vibrating screen, which comprises a bottom plate, a pre-tightening plate, an elastic system, a mounting frame and a pre-tightening bolt.

[0006] The pre-tightening plate is horizontally located above the bottom plate, and the mounting frame has a mounting plate located between the pre-tightening plate and the bottom plate.

[0007] The pre-tightening bolt is sequentially movable through the bottom plate, the mounting plate and the pre-tightening plate from bottom to top and can be connected and adjusted by a nut.

[0008] The elastic system has at least one group, and the elastic system comprises a first disc spring group and a second disc spring group. The first disc spring group is located between the pre-tightening plate and the mounting plate, and the second disc spring group is located between the mounting plate and the bottom plate. The first disc spring group and the second disc spring group generate positive stiffness under the pre-tightening force of the pre-tightening bolt.

[0009] The elastic system further comprises a first electromagnetic set and a second electromagnetic set, the first electromagnetic set is located between the first disc spring set and the pre-tightening plate, and the second electromagnetic set is located between the second disc spring set and the bottom plate, and the first electromagnetic set and the second electromagnetic set are used for providing adjustable negative stiffness.

[0010] On the basis of the above technical scheme, preferably, the first disc spring set and the second disc spring set are structurally identical, and each comprises a plurality of disc spring units arranged from top to bottom, the disc spring unit comprises an upper disc spring, a lower disc spring and a first blocking ring arranged between the upper disc spring and the lower disc spring, and the plurality of disc spring units are connected in series through a second blocking ring.

[0011] Further, preferably, the first electromagnetic set comprises a first coil and a first permanent magnet, the first coil is fixedly arranged on the bottom surface of the pre-tightening plate, one end of the first permanent magnet is inserted into the first coil, and the other end of the first permanent magnet is used for being connected with the top end of the first disc spring set, the second electromagnetic set comprises a second coil and a second permanent magnet, the second coil is fixedly arranged on the top surface of the bottom plate, one end of the second permanent magnet is inserted into the second coil, and the other end of the second permanent magnet is used for being connected with the bottom end of the second disc spring set.

[0012] On the basis of the above technical scheme, preferably, the current controller is further used for connecting the first coil and the second coil.

[0013] Preferably, the first electromagnetic set further comprises a third blocking ring arranged between the first permanent magnet and the first disc spring set, the upper end of the third blocking ring is fixedly connected with the first permanent magnet, and the lower end of the third blocking ring is used for being connected with the top end of the first disc spring set, the second electromagnetic set further comprises a fourth blocking ring arranged between the second permanent magnet and the second disc spring set, the lower end of the fourth blocking ring is fixedly connected with the second permanent magnet, and the upper end of the fourth blocking ring is used for being connected with the bottom end of the second disc spring set.

[0014] Preferably, the top surface and the bottom surface of the mounting plate are respectively provided with corresponding positioning portions, and the positioning portions are used for being correspondingly inserted into the first disc spring set or the second disc spring set.

[0015] In a second aspect, the present application discloses a stiffness adjusting method of an elastic support assembly of a vibrating screen.

[0016] Step one, when the load of the vibrating screen provided with the elastic support assembly changes, the inductive element receives the amplitude and frequency signals and transmits the signals to the current controller, the current controller changes the output current size according to the amplitude and frequency signals, the current controller outputs the current to the electromagnetic set, generates negative stiffness, and calculates the negative stiffness K N ;

[0017] Step two, the positive stiffness Kp of the disc spring set is calculated.

[0018] Step three, the overall stiffness K of the elastic support assembly is obtained by adding the positive stiffness Kp and the negative stiffness K N ; A ;

[0019] Step four, the size of the negative stiffness is changed by changing the size of the current, so that the positive stiffness of the disc spring group and the negative stiffness of the electromagnetic group interact to adjust the overall stiffness of the elastic support assembly.

[0020] On the basis of the above technical solutions, preferably, the calculation method of the positive stiffness Kp of the disc spring group is obtained by the following formula:

[0021]

[0022] Wherein, k1, k2…k n respectively represent the stiffness of a single disc spring;

[0023] The stiffness k of a single disc spring is calculated by the following formula:

[0024]

[0025] Wherein, E is the elastic modulus of the disc spring material, μ is the Poisson's ratio of the disc spring material, A is the calculation coefficient, h0 is the limit deformation variable when the disc spring is flattened, t is the thickness of the disc spring, and f is the rated maximum deformation, wherein the calculation coefficient A is calculated by the following formula:

[0026]

[0027] Wherein, D is the outer diameter of the disc spring, and d is the inner diameter of the disc spring.

[0028] On the basis of the above technical solutions, preferably, the calculation steps of the electromagnetic negative stiffness K N are as follows:

[0029] Step a, calculate the axial electromagnetic force F M generated by the interaction between n coils and n permanent magnets, and sum the electromagnetic force of all coil and permanent magnet pairs (p, q), wherein p and q represent the serial number of the coil and the permanent magnet respectively, and the formula is as follows:

[0030]

[0031] Step b, calculate the derivative of the axial electromagnetic force F M with respect to the axial displacement Z, and take its opposite number to obtain the electromagnetic negative stiffness K N , the formula is as follows:

[0032]

[0033] Step c, using the relationship between the current I of the coil and the axial displacement Z, the function relationship K1(I) and K2(I) of the electromagnetic negative stiffness K is determined by least square fitting of the scatter plot data in the range of given axial displacement Z, the formula is as follows: N

[0034] K N (I,Z)=K1(I)+K2(I)Z 2

[0035] Wherein, K1(I) and K2(I) are the coefficient functions related to current I obtained by data fitting.

[0036] On the basis of the above technical scheme, preferably, the positive stiffness provided by the first disc spring group and the second disc spring group is the same, and the negative stiffness provided by the first electromagnetic group and the second electromagnetic group is the same.

[0037] The present application has the following beneficial effects relative to the prior art:

[0038] 1、The elastic support assembly for the vibrating screen disclosed in the present application combines the electromagnetic group and the disc spring group to form an elastic system, and provides elastic support for the screen body of the vibrating screen. When the load increases, the current of the upper and lower electromagnetic groups is reduced to reduce the repulsive force between the electromagnetic groups and the disc spring group, so that the pre-tightening force of the pre-tightening bolt on the disc spring group is reduced, the force borne by the disc spring group is reduced, the stiffness of the disc spring group is increased, the stiffness of the system is increased, the problem of natural frequency reduction caused by the increase of the load is offset, the natural frequency of the system is increased, the load is adapted, and the working frequency remains unchanged. When the load decreases, the current of the upper and lower electromagnetic groups is increased to increase the electromagnetic repulsive force and the compression force on the disc spring group, so that the stiffness of the disc spring group is reduced, the overall stiffness of the system is reduced, the problem of natural frequency increase caused by the decrease of the load is offset, the natural frequency of the system is reduced, the load is adapted, and the working frequency remains unchanged. The entire elastic support assembly changes the electromagnetic force, and then changes the pre-tightening force of the disc spring group, so as to realize the change of the stiffness of the overall elastic support system. The frequency and amplitude of the disc spring vibrating screen during operation can be kept constant, and the stability of the disc spring vibrating screen can be improved.

[0039] 2、By constructing the disc spring group positive stiffness calculation method, on the one hand, the positive stiffness of the disc spring group can be accurately designed to ensure that the disc spring group can meet the specific load and deformation requirements, and on the other hand, a general calculation framework is provided, which is suitable for various engineering applications, and the stiffness characteristics of the disc spring group can be easily optimized to adapt to different working conditions and requirements.

[0040] ​3, the overall stiffness required by the acquisition system, after calculating the positive stiffness of the disc spring group, the required electromagnetic negative stiffness K A = Kp-K N required electromagnetic negative stiffness K N , through the function relationship between electromagnetic negative stiffness and current, the required current can be quickly calculated according to the required electromagnetic negative stiffness, and the target electromagnetic negative stiffness is achieved by adjusting the current, so as to meet the overall stiffness required by the system, the whole method is strong in operability, can guarantee the dynamic adjustment of the overall stiffness of the system, guarantee the frequency and amplitude of the disc spring vibrating screen to remain constant when working, and improve the stability of the disc spring vibrating screen. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0042] Fig. 1 is a perspective structural schematic view of the elastic support assembly for the vibrating screen disclosed by the present application;

[0043] Fig. 2 is a plane structural schematic view of the elastic support assembly for the vibrating screen disclosed by the present application;

[0044] Fig. 3 is an exploded schematic view of the elastic system disclosed by the present application;

[0045] Reference signs:

[0046] 1, bottom plate; 2, pre-tightening plate; 3, elastic system; 4, mounting frame; 41, mounting plate; 42, triangular plate; 43, connecting plate; 5, pre-tightening bolt; 51, nut; 31, first disc spring group; 32, second disc spring group; 33, first electromagnetic group; 34, second electromagnetic group; 310, disc spring unit; 3101, upper disc spring; 3102, lower disc spring; 3103, first stop ring; 311, second stop ring; 331, first coil; 332, first permanent magnet; 341, second coil; 342, second permanent magnet; 333, third stop ring; 343, fourth stop ring; 411, positioning part; S1, first positioning stop ring; S2, second positioning stop ring. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0048] As shown in the drawings, Figs. 1-3 The elastic support assembly for the vibrating screen comprises a bottom plate 1, a pre-tightening plate 2, an elastic system 3, a mounting frame 4 and a pre-tightening bolt 5.

[0049] The bottom plate 1 is horizontally fixedly installed on the rack of the vibrating screen, and the pre-tightening plate 2 is horizontally located above the bottom plate 1. The pre-tightening plate 2 and the bottom plate 1 are connected through the pre-tightening bolt 5.

[0050] The mounting frame 4 is used to be connected with the screen body of the vibrating screen. In the embodiment, the mounting frame 4 is in a tripod structure. The mounting frame 4 comprises a mounting plate 41 and two triangular plates 42 vertically arranged on the top of the mounting plate 41. The top of the two triangular plates 42 is fixedly provided with a connecting plate 43. The mounting plate 41 is located between the pre-tightening plate 2 and the bottom plate 1. The whole mounting frame 4 is in a tripod structure, and the overall structure is stable. The screen body of the vibrating screen can be installed with the connecting plate 43 at the top end of the mounting frame 4. The whole mounting frame 4 is installed between the pre-tightening plate 2 and the bottom plate 1, and is elastically supported through the elastic system 3. In the embodiment, the pre-tightening plate 2 is horizontally located in the mounting frame 4 and is located between the mounting plate 41 and the connecting plate 43. The pre-tightening plate 2 can move up and down in the mounting frame 4.

[0051] The elastic system 3 comprises at least one group. The elastic system 3 comprises a first disc spring group 31 and a second disc spring group 32. The first disc spring group 31 is located between the pre-tightening plate 2 and the mounting plate 41. The second disc spring group 32 is located between the mounting plate 41 and the bottom plate 1. The pre-tightening bolt 5 is sequentially movably passed through the bottom plate 1, the mounting plate 41 and the pre-tightening plate 2 from top to bottom and can be connected and adjusted through the nut 51.

[0052] When the screen body of the vibrating screen works, the screen body of the vibrating screen is loaded together with the material load on the mounting frame 4. The elastic system 3 provides elastic support for the screen body of the vibrating screen, and drives the screen body of the vibrating screen to complete the vibrating screening work under the action of the exciting force.

[0053] When the disc spring vibrating screen works, the first disc spring group 31 and the second disc spring group 32 can generate a positive stiffness acting on the mounting plate 41, which is opposite to the direction of the pre-tightening force generated by the pre-tightening bolt 5. The pre-tightening force generated by the pre-tightening bolt 5 can change the tightness of the bolt group and thus change the size of the pre-tightening force by rotating the nut 51. However, the positive stiffness generated by the disc spring group is a fixed value.

[0054] This is because the stiffness of the disc spring is defined as a characteristic inherent to its own physical structure, which does not change with changes in external conditions. The disc spring group provides the necessary elastic support for the vibrating screen, but can only work within the stiffness range set at the design time, and cannot dynamically adapt to the changing load conditions.

[0055] Therefore, the embodiment of the present application further designs the structure of the elastic support assembly, specifically, the elastic system 3 further comprises a first electromagnetic group 33 and a second electromagnetic group 34, the first electromagnetic group 33 is located between the first disc spring group 31 and the pre-tightening plate 2, and the second electromagnetic group 34 is located between the second disc spring group 32 and the bottom plate 1, the first electromagnetic group 33 and the second electromagnetic group 34 are used to provide adjustable negative stiffness.

[0056] In the above embodiment, the first electromagnetic group 33 and the second electromagnetic group 34 respectively generate electromagnetic force when current is passed, the electromagnetic force provided by the first electromagnetic group 33 can exert a compression force on the first disc spring group 31, and the electromagnetic force provided by the second electromagnetic group 34 can exert a compression force on the second disc spring group 32, more specifically, the electromagnetic group generates a repulsive force, and the stiffness of the disc spring group is adjusted by adjusting the repulsive force of the electromagnetic group, so as to maintain the working frequency and amplitude of the vibrating screen.

[0057] When the load increases, the mass of the vibrating system increases, and the natural frequency of the vibrating system decreases, in order to keep the original working frequency unchanged, the stiffness of the system needs to be increased, which is realized by reducing the current of the upper and lower electromagnetic groups, so as to reduce the repulsive force of the electromagnetic group on the disc spring group, which reduces the pre-tightening force of the pre-tightening bolt 5 on the disc spring group, so that the force borne by the disc spring group decreases, and the stiffness of the disc spring group increases, so as to increase the stiffness of the system, thereby offsetting the problem of the decrease of the natural frequency due to the increase of the load, improving the natural frequency of the system, so as to adapt to the increased load and keep the working frequency unchanged.

[0058] When the load decreases, the total mass of the vibrating system becomes smaller, and the natural frequency of the vibrating system increases. In order to keep the original working frequency unchanged, the stiffness of the system needs to be reduced, which is realized by increasing the current of the upper and lower electromagnetic groups, so as to increase the electromagnetic repulsive force and increase the compression force on the disc spring group, so that the stiffness of the disc spring group decreases, thereby reducing the overall stiffness of the system, thereby offsetting the problem of the increase of the natural frequency due to the decrease of the load, reducing the natural frequency of the system, so as to adapt to the decreased load and keep the working frequency unchanged.

[0059] As some preferred embodiments, the first disc spring set 31 and the second disc spring set 32 are of the same structure, each comprising a plurality of disc spring units 310 arranged from top to bottom, each disc spring unit 310 comprising an upper disc spring 3101, a lower disc spring 3102, and a first retainer ring 3103 arranged between the upper disc spring 3101 and the lower disc spring 3102, the upper disc spring 3101 and the lower disc spring 3102 being stacked together in opposite directions, and the plurality of disc spring units 310 being connected in series through a second retainer ring 311.

[0060] With the above technical solution, the series-connected disc spring units 310 can provide a cumulative elastic effect. This configuration allows the disc springs to produce a certain displacement when subjected to a load, which can increase the elastic range of the entire system. In addition, by adjusting the number of disc spring units 310 or replacing disc springs of different stiffness, the elastic characteristics of the system can be adjusted as needed. The disc springs are stacked together in opposite directions, which is generally to increase the overall stiffness of the spring set.

[0061] In the present embodiment, the upper disc spring 3101 and the lower disc spring 3102 are stacked together in opposite directions. In this configuration, when an external force acts on the disc spring set, each disc spring unit 310 will attempt to flatten, which reduces the overall displacement and thus achieves higher stiffness.

[0062] In the above embodiment, the first retainer ring 3103 connects the upper disc spring 3101 and the lower disc spring 3102 together in the axial direction, and the second retainer ring 311 connects the upper and lower disc spring units 310 together in the axial direction of the disc spring. In this way, the plurality of disc spring units 310 are connected in series, and the disc spring set formed by the plurality of disc spring units 310 can displace in the longitudinal direction during compression, ensuring the stability of the elastic deformation of the disc spring set.

[0063] In the above example, the first electromagnetic set 33 comprises a first coil 331 and a first permanent magnet 332, the first coil 331 being fixedly arranged on the bottom surface of the pre-tightening plate 2, one end of the first permanent magnet being inserted into the first coil 331, and the other end of the first permanent magnet 332 being used to connect with the top end of the first disc spring set 31. With this arrangement, by passing current through the first coil 331, the first permanent magnet can be driven to generate an electromagnetic force, thereby displacing towards the first disc spring set 31. The repulsive force generated by the first permanent magnet under the action of the current passing through the first coil 331 can compress the first disc spring set 31, thereby reducing the stiffness of the first disc spring set 31. Correspondingly, after the second electromagnetic set 34 is passed through the current, the repulsive force generated by the second permanent magnet under the action of the current passing through the second coil 341 can compress the second disc spring set 32, thereby reducing the stiffness of the second disc spring set 32.

[0064] In order to realize that the first electromagnetic group 33 exerts more stable force on the first disc spring group 31 in the axial direction of the first disc spring group 31, thereby providing negative stiffness, the first electromagnetic group 33 of the embodiment further comprises a third stop ring 333, the upper end of the third stop ring 333 is fixedly connected with the first permanent magnet 332, and the lower end of the third stop ring 333 is used to be connected with the top end of the first disc spring group 31. As some preferred embodiments, the upper end of the third stop ring 333 can be provided as a threaded segment, and the first permanent magnet is provided as a ring-shaped permanent magnet, and the upper end of the third stop ring 333 is connected with the first permanent magnet in a threaded connection manner.

[0065] In order to realize that the lower end of the third stop ring 333 can be axially positioned and connected with the top end of the first disc spring group 31, in some embodiments, a first positioning stop ring S1 can be arranged at the top end of the first disc spring group 31, the lower end of the first positioning stop ring S1 is inserted into the upper disc spring 3101, and the lower end of the third stop ring 333 is sleeved on the upper end of the first positioning stop ring S1, thereby realizing the stable connection of the first permanent magnet and the first disc spring group 31 in the axial direction. When the first permanent magnet generates electromagnetic thrust, the first permanent magnet and the third stop ring 333 synchronously exert downward pressure on the first disc spring group 31, so that the first disc spring group 31 is compressed, thereby reducing the stiffness of the first disc spring group 31.

[0066] Correspondingly, the second electromagnetic group 34 further comprises a fourth stop ring 343, the lower end of the fourth stop ring 343 is fixedly connected with the second permanent magnet 342, and the upper end of the fourth stop ring 343 is used to be connected with the bottom end in the second disc spring group 32. As some preferred embodiments, the lower end of the fourth stop ring 343 can be provided as a threaded segment, and the second permanent magnet is provided as a ring-shaped permanent magnet, and the lower end of the fourth stop ring 343 is connected with the second permanent magnet in a threaded connection manner.

[0067] In order to realize that the upper end of the fourth stop ring 343 can be axially positioned and connected with the bottom end of the second disc spring group 32, in some embodiments, a second positioning stop ring S2 can be arranged at the bottom end of the second disc spring group 32, the upper end of the second positioning stop ring S2 is inserted into the lower disc spring 3102, and the upper end of the fourth stop ring 343 is sleeved on the lower end of the second positioning stop ring S2, thereby realizing the stable connection of the second permanent magnet and the second disc spring group 32 in the axial direction. When the second permanent magnet generates electromagnetic thrust, the second permanent magnet and the fourth stop ring 343 synchronously exert upward pressure on the second disc spring group 32, so that the second disc spring group 32 is compressed, thereby reducing the stiffness of the second disc spring group 32.

[0068] In order to realize the positioning connection of the bottom end of the first disc spring group 31 with the top surface of the mounting plate 41 and the positioning connection of the top end of the second disc spring group 32 with the bottom surface of the mounting plate 41, the top surface and the bottom surface of the mounting plate 41 are respectively provided with corresponding positioning portions 411 in the embodiment, and the positioning portions 411 are used to be correspondingly inserted into the first disc spring group 31 or the second disc spring group 32.

[0069] The elastic support assembly disclosed in the embodiment further comprises a current controller connected to the first coil 331 and the second coil 341 respectively.

[0070] In a second aspect, the present application discloses a stiffness adjustment method for an elastic support assembly of a vibrating screen, and the stiffness adjustment method comprises the following steps:

[0071] Step one: when the load of the vibrating screen with the elastic support assembly changes, the inductive element receives the amplitude and frequency signals and transmits them to the current controller, the current controller changes the output current according to the amplitude and frequency signals, the current controller outputs the current to the electromagnetic assembly to generate negative stiffness, and the negative stiffness K is calculated. N .

[0072] The inductive element can be an accelerometer for directly measuring the vibration acceleration, from which the amplitude and frequency can be calculated, or a piezoelectric sensor for measuring pressure, acceleration or vibration by using the piezoelectric effect of the material. These inductive elements can enable the control system to understand the working state of the vibrating screen in real time, and adjust the output of the current controller accordingly, so as to change the negative stiffness of the electromagnetic assembly and realize the dynamic adjustment of the system stiffness.

[0073] The electromagnetic assembly generates a force under the action of the current, which is opposite to the restoring force (positive stiffness) provided by the disc spring set, thereby affecting the overall stiffness, and the current controller calculates the required negative stiffness K N .

[0074] Step two: the positive stiffness Kp of the disc spring set is calculated.

[0075] Step three: the overall stiffness K of the elastic support assembly is obtained by adding the positive stiffness Kp and the negative stiffness K N . A .

[0076] By adding the positive stiffness Kp of the disc spring set and the negative stiffness K N of the electromagnetic assembly, the overall stiffness K A of the elastic support assembly can be obtained. In theory, K A = Kp-K N , because the electromagnetic assembly provides a force opposite to the disc spring.

[0077] Step four: the size of the negative stiffness is changed by changing the size of the current, so that the positive stiffness of the disc spring set and the negative stiffness of the electromagnetic assembly interact to adjust the overall stiffness of the elastic support assembly. According to the needs of the system, the size of the negative stiffness is adjusted by changing the size of the current. Increasing the current will enhance the electromagnetic force, thereby increasing the negative stiffness; reducing the current will weaken the electromagnetic force, thereby reducing the negative stiffness.

[0078] The pre-tightening force of the disc spring set under the pre-tightening bolt is Fp, which, together with the load on the spring system, generates the positive stiffness of the disc spring set.

[0079] In this embodiment, the calculation method of the positive stiffness Kp of the disc spring set is obtained by the following formula:

[0080]

[0081] Where k1, k2…k n represent the stiffness of each disc spring in the set;

[0082] The calculation method of the stiffness k of a single disc spring is obtained by the following formula:

[0083]

[0084] Where E is the elastic modulus of the disc spring material, μ is the Poisson's ratio of the disc spring material, A is the calculation coefficient, h0 is the limit deformation variable when the disc spring is flattened, t is the thickness of the disc spring, and f is the rated maximum deformation, and the calculation coefficient A is calculated by the following formula:

[0085]

[0086] Where D is the outer diameter of the disc spring, and d is the inner diameter of the disc spring.

[0087] In the above embodiment, the positive stiffness Kp of the disc spring set is obtained by calculating the average value of the stiffness k of a single disc spring. Here, k1, k2…k n represent the stiffness of each disc spring in the set, and if all the disc springs are the same, Kp is the value of the stiffness k of any disc spring, because their average value is equal to the value of each term.

[0088] The above scheme for calculating the positive stiffness Kp of the disc spring set has the following technical effects:

[0089] 1. Accurate stiffness control: By calculating the stiffness of a single disc spring and averaging the combination, the positive stiffness Kp of the disc spring set can be accurately designed, ensuring that the disc spring set can meet specific load and deformation requirements.

[0090] 2. Optimized design: Using detailed mathematical models to design disc springs can optimize their geometric dimensions and material selection to achieve ideal mechanical properties, improving the reliability and durability of the system.

[0091] 3. Consideration of material properties: By including the elastic modulus E and Poisson's ratio μ, the actual behavior of the material is considered in the design, ensuring that the actual working performance of the disc spring is consistent with the theoretical calculation.

[0092] 4. Adaptability: The design method can be applied to disc springs of different sizes, materials, and shapes, providing a general calculation framework that is adaptable to various engineering applications.

[0093] 5. Easy optimization: By adjusting the parameters of the disc spring (such as outer diameter D, inner diameter d, material, etc.), the stiffness characteristics of the disc spring set can be easily optimized to adapt to different working conditions and requirements.

[0094] In this embodiment, the electromagnetic negative stiffness K N is calculated as follows:

[0095] Step a, calculate the axial electromagnetic force F M generated by the interaction between n coils and n permanent magnets, by summing the electromagnetic forces F of all coil and permanent magnet pairs (p, q), where p and q represent the serial numbers of the coil and permanent magnet, respectively, as follows:

[0096]

[0097] Step b, calculate the derivative of the axial electromagnetic force F M with respect to the axial displacement Z, and take its opposite number, to obtain the electromagnetic negative stiffness K N , as follows:

[0098]

[0099] The above formula shows that the electromagnetic negative stiffness is K N , which is obtained by calculating the negative derivative of the electromagnetic force F M with respect to the axial displacement Z. In this case, the derivative represents the rate of change of the electromagnetic force F M with respect to a small change in the axial displacement Z. Taking the negative number is because the stiffness is defined as the positive value of the rate of change of force with respect to displacement, and when the force decreases with the increase of displacement, it indicates a negative stiffness.

[0100] Step c, using the relationship between the current I of the coil and the axial displacement Z, determine the functional relationship K1(I) and K2(I) of the electromagnetic negative stiffness K N by fitting the scatter plot data within a given range of axial displacement Z by the least squares method, as follows:

[0101] K N (I, Z) = K1(I) + K2(I)Z 2

[0102] where K1(I) and K2(I) are coefficient functions related to the current I obtained by data fitting.

[0103] In the above electromagnetic negative stiffness adjustment process, the purpose is to obtain the required electromagnetic negative stiffness, and the adjustment means is to change the current. Specifically, first, the required electromagnetic negative stiffness is needed to meet the dynamic characteristics requirements of the system, and then the electromagnetic negative stiffness is actually achieved by adjusting the current.

[0104] Generally, after the functional relationship between the electromagnetic negative stiffness and the current is obtained, the required current is calculated according to the required negative stiffness. Therefore, the direct parameter we adjust is the current, and the electromagnetic negative stiffness is the result of current adjustment.

[0105] In actual engineering applications, a target electromagnetic negative stiffness value is usually determined according to the requirements of the system. Then, using the relationship derived from experiments or theory, the current value required to achieve the target electromagnetic negative stiffness is calculated. Then, the current is adjusted by controlling the power supply, so as to adjust the electromagnetic negative stiffness.

[0106] The stiffness adjustment method of the elastic support assembly disclosed in the application is that in the actual working process of the vibrating screen, the overall stiffness K A of the system is determined by the positive stiffness K P of the disc spring group and the negative stiffness K N provided by the electromagnetic group. In actual applications, K P is usually fixed because it depends on the material and geometry of the physical disc spring, and K N can be adjusted by changing the current flowing through the electromagnetic component.

[0107] In the case of load change, the overall stiffness K A of the system can be obtained by direct measurement or by some sensing technology. Once K A and K P are known, the current K A can be calculated according to the formula K N = Kp-K N .

[0108] If the system needs a specific overall stiffness K A to adapt to different working conditions, K N can be adjusted to achieve this goal by the following steps:

[0109] 1) Determine the target overall stiffness K A,target .

[0110] 2) Calculate the current disc spring group stiffness Kp.

[0111] 3) Calculate the required electromagnetic negative stiffness K N,target using (K N,target = K A,target -Kp).

[0112] 4), adjust the current I to change K N , find the corresponding current I to achieve the required K N , through the relationship K 2 (I,Z) = K1(I) + K2(I)Z N,target .

[0113] In order to maintain the stability of the system under different loads and working conditions, it is usually necessary to implement closed-loop control. That is, the overall stiffness K A needs to be continuously monitored, and the current I needs to be dynamically adjusted according to the actual situation to maintain K N around the target value. Through this method, precise adjustment of the overall stiffness of the elastic support assembly can be achieved, ensuring the performance and stability of the system under various working conditions.

[0114] The stiffness adjustment method disclosed by the present application can obtain the overall stiffness required by the system. After calculating the positive stiffness of the disc spring group, the required electromagnetic negative stiffness K A can be quickly calculated through the formula K N = Kp-K N , and the required current can be quickly calculated according to the required electromagnetic negative stiffness through the functional relationship between electromagnetic negative stiffness and current. The target electromagnetic negative stiffness can be achieved by adjusting the current, thereby meeting the overall stiffness required by the system. The entire method is highly operable, can ensure dynamic adjustment of the overall stiffness of the system, and can ensure that the frequency and amplitude of the disc spring shaker remain constant during operation, thereby improving the stability of the disc spring shaker.

[0115] As some preferred embodiments, the positive stiffness provided by the first disc spring group and the second disc spring group is the same, and the negative stiffness provided by the first electromagnetic group and the second electromagnetic group is the same. With this arrangement, the displacement of the upper and lower disc spring groups during compression is consistent, avoiding fatigue damage to a certain disc spring group and affecting the service life of the elastic support assembly. At the same time, the negative stiffness provided by the first electromagnetic group and the second electromagnetic group is the same, which can make the performance of the vibrating screen system more stable.

[0116] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An elastic support assembly for a vibrating screen, characterized in that, Includes base plate (1), pretension plate (2), elastic system (3), mounting frame (4) and pretension bolts (5); The pretension plate (2) is horizontally positioned above the base plate (1), and the mounting frame (4) has a mounting plate (41) located between the pretension plate (2) and the base plate (1); The pre-tightening bolt (5) moves sequentially from bottom to top through the base plate (1), mounting plate (41) and pre-tightening plate (2), and can be connected and adjusted by the nut (51); The elastic system (3) has at least one set, which includes a first disc spring group (31) and a second disc spring group (32). The first disc spring group (31) is located between the preload plate (2) and the mounting plate (41), and the second disc spring group (32) is located between the mounting plate (41) and the base plate (1). The first disc spring group (31) and the second disc spring group (32) generate positive stiffness under the preload force of the preload bolt (5). The elastic system (3) further includes a first electromagnetic group (33) and a second electromagnetic group (34). The first electromagnetic group (33) is located between the first disc spring group (31) and the pretension plate (2), and the second electromagnetic group (34) is located between the second disc spring group (32) and the base plate (1). The first electromagnetic group (33) and the second electromagnetic group (34) are used to provide adjustable negative stiffness.

2. The elastic support assembly for a vibrating screen as described in claim 1, characterized in that, The first disc spring group (31) and the second disc spring group (32) have the same structure, both including multiple disc spring units (310) arranged from top to bottom. Each disc spring unit (310) includes an upper disc spring (3101), a lower disc spring (3102), and a first retaining ring (3103) disposed between the upper disc spring (3101) and the lower disc spring (3102). The multiple disc spring units (310) are connected in series with each other through a second retaining ring (311).

3. The elastic support assembly for a vibrating screen as described in claim 2, characterized in that, The first electromagnetic assembly (33) includes a first coil (331) and a first permanent magnet (332). The first coil (331) is fixedly mounted on the bottom surface of the pre-tightening plate (2). One end of the first permanent magnet (332) is inserted into the first coil (331), and the other end of the first permanent magnet (332) is used to connect with the top end of the first disc spring assembly (31). The second electromagnetic assembly (34) includes a second coil (341) and a second permanent magnet (342). The second coil (341) is fixedly mounted on the top surface of the base plate (1). One end of the second permanent magnet (342) is inserted into the second coil (341), and the other end of the second permanent magnet (342) is used to connect with the bottom end of the second disc spring assembly (32).

4. The elastic support assembly for a vibrating screen as described in claim 3, characterized in that, It also includes a current controller, which is used to connect the first coil (331) and the second coil (341) respectively.

5. The elastic support assembly for a vibrating screen as described in claim 3, characterized in that, The first electromagnetic assembly (33) further includes a third retaining ring (333) disposed between the first permanent magnet (332) and the first disc spring assembly (31). The upper end of the third retaining ring (333) is fixedly connected to the first permanent magnet (332), and the lower end of the third retaining ring (333) is used to connect with the top end of the first disc spring assembly (31). The second electromagnetic assembly (34) further includes a fourth retaining ring (343) disposed between the second permanent magnet (342) and the second disc spring assembly (32). The lower end of the fourth retaining ring (343) is fixedly connected to the second permanent magnet (342), and the upper end of the fourth retaining ring (343) is used to connect with the bottom end of the second disc spring assembly (32).

6. The elastic support assembly for a vibrating screen as described in claim 2, characterized in that, The top and bottom surfaces of the mounting plate (41) are respectively provided with corresponding positioning parts (411), which are used to be inserted into the first disc spring group (31) or the second disc spring group (32).

7. The method for adjusting the stiffness of the elastic support assembly for a vibrating screen according to claim 4, characterized in that, The stiffness adjustment method has the following steps: Step 1: When the load on the vibrating screen equipped with the elastic support assembly changes, the sensing element receives the amplitude and frequency signals and transmits them to the current controller. The current controller changes the output current based on the amplitude and frequency signals, and outputs the current to the electromagnetic assembly, generating negative stiffness, and calculates the negative stiffness K. N ; Step 2: Calculate the normal stiffness Kp of the disc spring assembly; Step 3: Using positive stiffness Kp and negative stiffness K N The overall stiffness K of the elastic support component is obtained by summing the results. A ; Step 4: By changing the magnitude of the current, the magnitude of the negative stiffness is changed, so that the positive stiffness of the disc spring assembly and the negative stiffness of the electromagnetic assembly interact to adjust the overall stiffness of the elastic support assembly.

8. The method for adjusting the stiffness of the elastic support assembly for a vibrating screen as described in claim 7, characterized in that, The normal stiffness Kp of the disc spring assembly is calculated using the following formula: Where k1, k2…k n These represent the stiffness of a single disc spring; The stiffness k of a single disc spring is calculated using the following formula: Where E is the elastic modulus of the disc spring material, μ is the Poisson's ratio of the disc spring material, A is the calculation coefficient, h0 is the limiting deformation of the disc spring under compression, t is the thickness of the disc spring, and f is the rated maximum deformation. The calculation coefficient A is calculated by the following formula: in, D is the outer diameter of the disc spring, and d is the inner diameter of the disc spring.

9. The method for adjusting the stiffness of the elastic support assembly for a vibrating screen as described in claim 7, characterized in that, Electromagnetic negative stiffness K N The calculation steps are as follows: Step a: Calculate the axial electromagnetic force F generated by the interaction between n coils and n permanent magnets. M Through the electromagnetic force on all coils and permanent magnet pairs (p, q) Summing the results, where p and q represent the indices of the coil and permanent magnet respectively, yields the following formula: Step b, by applying the axial electromagnetic force F M The electromagnetic negative stiffness K is obtained by calculating the derivative with respect to the axial displacement Z and taking its opposite. N d represents the differentiation operation, and the formula is as follows: Step c: Using the relationship between the coil current I and the axial displacement Z, determine the electromagnetic negative stiffness K by fitting scatter plot data within a given range of axial displacement Z using the least squares method. N The functional relationships K1(I) and K2(I) are given by the following formulas: K N (I,Z)=K1(I)+K2(I)Z 2 Among them, K1(I) and K2(I) are coefficient functions related to current I obtained by data fitting.

10. The method for adjusting the stiffness of the elastic support assembly for a vibrating screen as described in claim 7, characterized in that, The first disc spring group and the second disc spring group provide the same positive stiffness, and the first electromagnetic group and the second electromagnetic group provide the same negative stiffness.

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