Double-motor-driven energy-saving horizontal elliptical vibrating screen and parameter determination method thereof

Abstract

The present application belongs to the technical field of vibrating screening device, and relates to a double-machine driving energy-saving horizontal elliptical vibrating screen and a parameter determination method thereof. The vibrating screen comprises two vibration exciters, two masses and springs. The vibration isolation springs are symmetrically distributed and connected between the foundation and the outer mass. The two vibration exciters are arranged on the outer mass and rotate in the same direction, and are distributed below the feed inlet and above the discharge outlet of the outer mass. The inner mass comprises a plurality of masses, which are connected to the outer mass through connecting rods, shear rubber springs and spring seats. The double-mass structure is adopted, the inner mass is driven to vibrate by the outer mass through the shear rubber springs, so that an effective sub-resonance system is formed, and the performance of the whole machine is not affected by the change of the feed quantity. Compared with the single-mass structure, the double-mass system can achieve the same vibration intensity with smaller power, thereby reducing energy consumption. The motion trajectory of the inner mass is an ellipse, which has the advantages of circular motion and linear motion screening machines, and effectively improves the processing capacity and screening efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vibrating screening devices, in particular to a double-machine-driven energy-saving horizontal elliptical vibrating screen and a parameter determination method thereof. BACKGROUND

[0002] As a mature screening device, vibrating screens are widely used in industrial and mining enterprises such as coal preparation plants and ore dressing plants, and in the metallurgical, chemical, transportation and other industrial departments. The single-mass super-stable energy-saving screen described in CN1623683 patent document is driven by a single motor through an elastic crank connecting rod to make the single-mass screen body vibrate linearly along the arrangement direction of the main vibration spring. The single-mass circular vibrating screen driven by a single vibrating motor is disclosed in CN103170453A patent document. The circular vibrating screen described in CN201702106U patent document is driven by a single motor through a motor transmission device to make the single-mass screen box vibrate in a circular trajectory. As described above, the traditional vibrating screen is mostly a single-mass linear vibrating screen or a circular vibrating screen driven by a single machine. With the development of industry, the single-mass vibrating screen driven by a single machine cannot meet the requirements of low energy consumption, high efficiency and high yield of industry. The disadvantages are as follows:

[0003] 1. The single-machine-driven vibrating screen requires a relatively large power for the motor itself during operation, resulting in a relatively large size of the motor, high technical requirements for the motor, high cost, and low utilization rate of electric energy.

[0004] 2. The single-machine-driven vibrating screen can only be used for screening of small equipment. In order to facilitate automatic control and intelligent development, the screening equipment is developing towards large-scale with excellent performance. The single-machine-driven vibrating screen cannot meet the demand of large-scale screening machines.

[0005] 3. The single-mass vibrating screen works at an ultra-distant resonance frequency, requiring a large excitation force, high power consumption, and small amplitude, resulting in low screening efficiency.

[0006] With the global resource depletion and environmental deterioration, low carbon, energy saving and environmental protection have become the main direction of sustainable development of countries around the world. The design and development of energy-saving and environmentally friendly vibrating screens are the mainstream of future development. In order to meet the development requirements of large-scale, energy-saving and high screening efficiency of vibrating screens, the present application proposes a double-machine-driven energy-saving horizontal elliptical vibrating screen and a parameter determination method thereof. SUMMARY

[0007] Based on the deficiencies of the prior art, the present application proposes a double-machine-driven energy-saving horizontal elliptical vibrating screen and a parameter determination method thereof.

[0008] The technical scheme of the present application is as follows: a double-machine driving energy-saving horizontal elliptical vibrating screen, comprising two vibration exciters 1, an inner mass 6, an outer mass 7, a vibration isolation spring 4 and a shear spring 3; the outer mass 7 is connected to a foundation through symmetrically distributed vibration isolation springs 4; two vibration exciters 1 are arranged on the outer mass 7, the two vibration exciters 1 rotate in the same direction and are symmetrically distributed about the mass center origin of the outer mass 7, and the two vibration exciters 1 are located at two end portions outside the feed inlet and the discharge outlet of the outer mass 7; the inner mass 6 comprises n parallel arranged masses, each mass is connected and fixed to a spring seat 5 on the outer mass 7 through a plurality of guide rods 2 and shear springs 3; the guide rod 2 forms an angle β with the horizontal direction.

[0009] Further, the angle β can be adjusted, and is between 30 degrees and 60 degrees, such as 45 degrees.

[0010] A parameter determination method of a double-machine driving energy-saving horizontal elliptical vibrating screen, comprising the following steps:

[0011] Step 1, establishing a double-machine driving double-mass vibration system motion differential equation and a relative motion differential equation of the inner mass and the outer mass in the y direction;

[0012] Oxy is set as a fixed coordinate, the rotation centers of the two vibration exciters 1 are o 01 and o 02 , and the corresponding phases of the two vibration exciters 1 are and

[0013] Step 2, determining a synchronization condition;

[0014] Step 3, determining a stability condition.

[0015] The double-machine driving double-mass vibration system motion differential equation is established as follows:

[0016] x, y, ψ, are selected as generalized coordinates, and based on the Lagrange equation, the motion differential equation of the double-machine driving double-mass vibration system is:

[0017]

[0018] wherein, M2 = m + m 01 + m 02 , M = M1 + M2, J 0i = m 0i r 2 = J0, J = M1 e 2 , θ1 = π, θ2 = 0, θ i is an angle between the line o 0i O and the x axis;

[0019] where M is the total mass of the dual-motor driven dual-mass vibration system, M = M1 + M2; M1 is the mass of the inner mass, m w is the mass of the wth mass of the inner mass, w = 1, 2, 3...n; M2 is the total mass of the outer mass and two exciters, M2 = m + m 01 +m 02 ; m 0i is the mass of the eccentric block of the exciter i, i = 1, 2; J is the moment of inertia of the entire dual-motor driven dual-mass vibration system; J 0i is the moment of inertia of the exciter i, i = 1, 2; l0 is the distance from the rotation axis o 0i of the exciter i to the center O of the outer mass, i = 1, 2; l e is the equivalent rotation radius of the dual-motor driven dual-mass vibration system; r is the eccentricity of the exciter; f dj is the shaft damping coefficient of the induction motor j, j = 1, 2; T ej is the electromagnetic output torque of the induction motor j, j = 1, 2; k 2x ,k ψ are the spring stiffnesses of the dual-motor driven dual-mass vibration system in the x and ψ directions; k1, k 2y are the spring stiffnesses of the inner mass and the outer mass in the y direction, respectively; f 2x ,f ψ are the damping coefficients of the dual-motor driven dual-mass vibration system in the x and ψ directions; f1, f 2y are the damping coefficients of the inner mass and the outer mass in the y direction, respectively; is the first-order time derivative; is the second-order time derivative.

[0020] The relative motion differential equations of the inner mass and the outer mass in the y direction are established as follows:

[0021] The following settings are made:

[0022] 1) The masses of the two exciters are the same, i.e., m 01 = m 02 = m0;

[0023] 2) The average phase of the two exciters is and the phase difference is a, which satisfies

[0024] 3) The average angular velocity of the two exciters when the dual-motor driven dual-mass vibration system is synchronously and stably running is set as ω m0 ;

[0025] 4) When the dual-motor driven dual-mass vibration system is synchronously running, the terms of and in equation (1) are omitted.

[0026] 5) stiffness k of the vibration isolation spring (4) in the x direction 2x and stiffness k in the y direction 2y much smaller than k1;

[0027] 6) damping coefficient f 2y is 0;

[0028] According to the first two equations in equation (1), the relative motion differential equation of the endosoma and the exosoma in the y direction is obtained as follows:

[0029]

[0030] In equation (2),

[0031]

[0032]

[0033] where M In is the induced mass of the double-motor-driven double-soma vibration system; y 12 is the relative displacement of the endosoma and the exosoma in the y direction;

[0034] By considering equation (2), the natural frequency ω0 of the relative motion of the endosoma and the exosoma in the x direction is obtained, which is regarded as the natural frequency of the main vibration system including the endosoma 6, the exosoma 7, the shear spring 3 and the two excitation devices 1.

[0035]

[0036] The relative motion of the endosoma and the exosoma in the y direction is rewritten as follows:

[0037]

[0038] where,

[0039]

[0040] When z0=1, i.e., ω m0 = ω0, the maximum value of R 12 in equation (4) is obtained at the resonance point; the natural frequency ω0 of the main vibration system is the natural frequency of the relative motion of the endosoma and the exosoma in the y direction in anti-phase;

[0041] According to the mathematical solution of the extremum principle, the response amplitude of the relative motion in anti-phase is expressed as:

[0042]

[0043] The determination of the synchronization condition is specifically as follows:

[0044] For the first two equations of formula (1), the transfer function method based on Laplace transform is adopted, and considering formula (2), the displacement responses of the endoskeleton and ectoskeleton of the main vibration system in x direction, y direction and ψ direction are expressed as:

[0045]

[0046] wherein,

[0047]

[0048] According to the first two equations in formula (1), the characteristic equations of the endoskeleton and ectoskeleton in y direction and two natural frequencies are obtained:

[0049]

[0050]

[0051] wherein,

[0052]

[0053] b=[M1(k1+k 2y )] 2 +(M2k1) 2 +2M1M2k1(k1-k 2y )

[0054] Combining formula (5), ignoring k 2y , ω Inv , ω Inv and ω Sa are respectively the natural frequencies of the endoskeleton and ectoskeleton in y direction in anti-phase and in-phase;

[0055] When the two exciters 1 can reach a stable synchronous state, i.e. Differentiating x, y2 and ψ in formula (6) with respect to time t, the following equations are obtained: and Substituting them into the last two equations of formula (1), and Taking the mean value of the above integral, the average equilibrium equation of the two exciters 1 is as follows:

[0056] T e01 -d f1 -f d1 ω m0 =0 (9)

[0057] T e02 -d f2-f d2 ω m0 = 0 (10)

[0058] where,

[0059]

[0060]

[0061]

[0062] W cc defined as dimensionless coupling coefficient, T e0j is the electromagnetic torque of induction motor when the double-motor double-mass vibration system is running synchronously and stably, j = 1, 2;

[0063] Equation (9) and equation (10) are arranged as

[0064] (T e01 + T e02 ) - (f d1 + f d2 ) ω m0 = T L (11)

[0065]

[0066] where, T L = d f1 + d f2 , T D = T R1 - T R2 , T C = m0r 2 ω 2 m0 W cc , T R1 = T e01 - f d1 ω m0 , T R2 = T e02 - f d2 ω m0 ; in the equation, T L is the total load of two motors; T Rj is the effective electromagnetic output torque of motor j, j = 1, 2; T D is the difference of effective electromagnetic output torque of two motors; T C is the frequency capture torque;

[0067] In equation (12), according to |sin(2α)|≤1, the synchronization criterion of two excitators is obtained as follows

[0068] |TD |≤T C (13)

[0069] The theoretical basis for achieving synchronous operation of a dual-motor driven dual-mass vibration system is described as follows: the absolute value of the difference between the effective electromagnetic output torques of the two motors should be less than or equal to the frequency trapping torque. Based on the above analysis, the premise for achieving synchronization of a dual-motor driven dual-mass vibration system is that the frequency trapping torque is sufficient to overcome the difference between the two motors, and then the phase difference is adjusted by energy distribution between the exciters to achieve synchronization.

[0070] When the parameters of the two exciters are exactly the same, then T D =T R1 -T R2 =0; According to equation (12), the phase difference between the two exciters is stable at 0 or π; Define the synchronization capability coefficient ζ between the two exciters, i.e.

[0071]

[0072] In equation (14), ζ is ω m0 Nonlinear functions.

[0073] The specific conditions for determining stability are as follows.

[0074] In formula (12) There are two solutions: one stable and the other unstable. Based on Hamilton's principle, the stability of the synchronized state is studied, and the kinetic energy T and potential energy V of the entire dual-machine-driven two-mass vibration system are expressed as follows:

[0075]

[0076]

[0077] Hamilton's average motion over one period is denoted as I, and is expressed as...

[0078]

[0079] Solution of stable phase difference under synchronous conditions Corresponding to the minimum point of I, therefore, the second derivative with respect to I is positive, i.e.

[0080]

[0081] In the formula, H is the stability coefficient;

[0082] Substituting equation (17) into equation (18), the stability criterion for a dual-machine-driven dual-mass vibration system is given by the following equation.

[0083]

[0084] wherein,

[0085]

[0086]

[0087] According to formula (19), the stability criterion requires that the product of stability capability coefficient H and the cosine value of the phase difference of the two exciters is greater than 0; the parameter H is used for measuring the stability of the system, and the greater the value is, the stronger the stability capability of the double-motor-driven double-mass vibration system is; in order to meet the stability criterion, when , H>0; when , H<0.

[0088] In order to realize energy saving, the main vibration system should work in a sub-resonance state. The running frequency of the motor is adjusted by using a frequency converter to adjust the running frequency of the induction motor, and the running frequency ω of the motor is adjusted to be lower than the natural frequency ω0 of the main vibration system, so that the main vibration system works in a sub-resonance state. Compared with the main vibration system working in a super-resonance state, the motor running frequency is small, the system energy consumption can be reduced, and thus energy saving is realized.

[0089] The beneficial effects of the present application are:

[0090] 1) The double-mass is a new type of structure of a vibration device, one mass is used as an exciting mass, and another working mass is driven to obtain the required amplitude. The two masses are connected through springs, so that a sensitive sub-resonance system is formed. In the sub-resonance state, the change of the feeding amount does not affect the play of the overall mechanical performance. Compared with the single-mass system, the double-mass system can achieve the same effect with smaller power, and the double-mass system can well reduce the power consumption.

[0091] 2) The double-motor driving applies the self-synchronization theory, compared with the traditional single-motor driving, the driving frequency is increased, the screening is more thorough, the working efficiency is further improved, and the conditions for further large-scale screening equipment are provided.

[0092] 3) The motion trajectory of the inner mass is an ellipse, which has the advantages of circular motion and linear motion screening machines. The long axis of the elliptical motion trajectory can be used for material transportation, and the short axis of the elliptical motion trajectory can make the screened material more loose. Therefore, its characteristics are: thin material layer, good layering, particles are not easy to block, conveying speed is large, and screening efficiency is high. Its processing capacity can be increased by 25% to 30% compared with circular or linear vibration screens. BRIEF DESCRIPTION OF DRAWINGS

[0093] Figure 1 It is a dynamics model diagram of the double-motor-driven energy-saving horizontal elliptical vibration screen.

[0094] Figure: 1. Exciter; 2. Guide rod; 3. Shear spring; 4. Isolation spring; 5. Spring seat; 6. Inner mass; 7. Outer mass.

[0095] Figure: O - center of the whole system; o 01 - center of rotation of the first exciter; o 02 - center of rotation of the second exciter; - phase angle of rotation of the first exciter; - phase angle of rotation of the second exciter; m 01 - mass of the first exciter; m 02 - mass of the second exciter; r - eccentricity of the exciter i (i = 1, 2); θ i - angle between O and x axis; k 0i - angle between O and x axis; k 2x - angle between O and x axis; k ψ - spring stiffness in x and ψ directions; k1, k 2y - spring stiffness in y direction of inner and outer mass respectively; lo - distance between center of rotation of the exciter and center of the system;

[0096] Figure 2(a) is the simulation result of motor speed;

[0097] Figure 2(b) is the simulation result of phase difference of two exciters;

[0098] Figure 2(c) is the simulation result of movement trajectory of inner and outer mass. DETAILED DESCRIPTION

[0099] The technical solution of the present application is described below in combination with the drawings and specific embodiments.

[0100] A double-motor driven energy-saving horizontal elliptical vibrating screen, such as Figure 1As shown, it comprises an ectoplasm 7 and an endoplasm 6, two excitation generators 1 are arranged on the ectoplasm 7, each of the excitation generators 1 has a set of eccentric blocks, the excitation force is changed by changing the included angle of the main eccentric block and the auxiliary eccentric block, so as to adjust the amplitude of the screening machine; the set of eccentric blocks is driven by an induction motor and rotates around the center of the respective rotation axis, the rotation directions of the two excitation generators 1 are the same; the front part is a discharge port, the rear part is a feeding port, the two excitation generators 1 are symmetrically distributed on the non-feeding port and the non-discharge port about the center of the mass of the ectoplasm 7 and do not affect the feeding and discharging; the ectoplasm 7 is connected with the ground through the symmetrically distributed metal spiral spring 4. The endoplasm 6, i.e. the main vibrating ectoplasm, is composed of n ectoplasms and is connected with the ectoplasm 7 through the guide rod 2, the shearing rubber spring 3 and the spring seat 5; the guide rod 2 has a certain included angle β with the horizontal direction; the endoplasm 6 composed of the n ectoplasms has a certain installation inclination angle with the horizontal direction; the installation inclination angle is closely related to the processing capacity and the screening efficiency of the screening machine, different values are taken according to different purposes of the screening machine, for example, the installation inclination angle is taken as 0° if there is no special requirement. The excitation generator can be composed of an eccentric rotor driven by an induction motor or directly adopt a vibration motor, and the excitation generator is installed on the ectoplasm. Under the action of the excitation force, the ectoplasm makes a circular motion; under the shearing deformation of the shearing spring, the relative motion in the y direction between the endoplasm and the ectoplasm is generated, so that the endoplasm makes an elliptical motion.

[0101] When the set of eccentric blocks is driven by the induction motor, the excitation force is generated to drive the ectoplasm 7 to vibrate, when the two motors are synchronously and stably operated in the same direction, the center of mass of the ectoplasm 7 makes a circular motion under the action of the excitation force. The ectoplasm 7 drives the endoplasm 6 to vibrate through the shearing rubber spring 3, due to the shearing action of the shearing rubber spring 3, the endoplasm 6 and the ectoplasm 7 generate a relative linear motion in the shearing direction, so that the original circular motion of the endoplasm 6 is pulled as the major axis of the elliptical motion in the shearing direction. The ectoplasm 7 drives the endoplasm 6 to vibrate through the shearing rubber spring 3, so as to form a sensitive sub-resonance system, which reduces the consumption of electric energy of the system and ensures the high performance and high efficiency of the equipment in the use process.

[0102] In order to further verify the above theoretical results and conclusions, simulation analysis is carried out.

[0103] It is assumed that the parameters of the vibration system are as follows: based on the parameter determination method, the system parameters are set as follows: M1=900kg, M2=1100kg, J=400kg·m 2 , m 01 = m 02 = m0=10kg, J 01 = J 02 = J0=0.225kg·m 2 , k 2x = k 2y =550.5kN / m, k1=17800kN / m, k ψ= 300 kN / m, f 2x = f 2y = f1= 7.66 kN-s / m, f ψ = 5.7 kN-s / rad, r = 0.15 m. Motor type: three-phase squirrel-cage, 50 Hz, 380 V, 6-pole, 0.75 kW, rated speed 980 r / min.

[0104] Fig. 2 is the simulation results of the motor speed, the phase difference of the exciter and the trajectory of the mass. Since two same induction motors are selected, the motors reach the synchronous running state in a very short time. When the motors run stably, the motor speed is about 980 r / min, and the phase difference of the exciter is 2a = 0°, as shown in Figs. 2(a) and (b). As shown in Fig. 2(c), the trajectory of the outer mass is approximately a circle, which is due to the coupling between the inner and outer masses, so that the trajectory of the outer mass becomes an ellipse. The inner mass is stretched in the shear direction of the shear rubber spring to become the major axis, and the trajectory becomes an ellipse, and the amplitude in the y direction is about 2.5 mm.

Claims

1. A parameter determination method of a double-motor-driven energy-saving horizontal elliptical vibrating screen, characterized in that the double-motor-driven energy-saving horizontal elliptical vibrating screen comprises two exciters (1), an inner mass (6), an outer mass (7), vibration isolation springs (4) and shear springs (3); the outer mass (7) is connected to the foundation through symmetrically distributed vibration isolation springs (4); two exciters (1) are arranged on the outer mass (7) and rotate in the same direction and are symmetrically distributed about the mass center origin of the outer mass (7), and are located at two end portions other than the feed inlet and the discharge outlet of the outer mass (7); the inner mass (6) comprises n parallel arranged masses, each mass is connected and fixed to the spring seat (5) on the outer mass (7) through a plurality of guide rods (2) and shear springs (3); the guide rod (2) forms an angle β with the horizontal direction; The parameter determination method comprises the following steps: Step 1, establishing a motion differential equation of the double-motor-driven double-mass vibration system and a relative motion differential equation of the inner mass and the outer mass in the y direction; Step 2, determining a synchronization condition; Let Oxy be a fixed coordinate, and the rotation centers of the two exciters (1) are o 01 and o 02 , and the corresponding phases of the two exciters (1) are respectively and Step 3, determining a stability condition; The motion differential equation of the double-motor-driven double-mass vibration system is established as follows: The angle β is 30-60 degrees. Select x, y, ψ, The motion differential equation of the double-mass vibration system driven by the double-machines is: wherein M2 = m + m 01 + m 02 , M = M1 + M2, J 0i = m 0i r 2 = J0, θ1 = π, θ2 = 0, θ i is the angle between the line o 0i and the x-axis; In the formula, M is the total mass of the double-motor-driven double-mass vibration system, M=M1+M2; M1 is the mass of the inner mass, m w is the mass of the wth mass of the inner mass, w=1, 2, 3…n; M2 is the total mass of the outer mass and two exciters, M2=m+m 01 +m 02 ; m 0i is the mass of the eccentric block of the exciter i, i=1, 2; J is the moment of inertia of the entire double-motor-driven double-mass vibration system; J 0i is the moment of inertia of the exciter i, i=1, 2; l0 is the distance from the rotation axis o 0i of the exciter i to the center O of the outer mass, i=1, 2; l e is the equivalent rotation radius of the double-motor-driven double-mass vibration system; r is the eccentricity of the exciter; f dj is the shaft damping coefficient of the induction motor j, j=1, 2; T ej is the electromagnetic output torque of the induction motor j, j=1, 2; k 2x ,k ψ is the spring stiffness of the double-motor-driven double-mass vibration system in the x and ψ directions; k1, k 2y are respectively the spring stiffness of the inner mass and the outer mass in the y direction; f 2x ,f ψ is the damping coefficient of the double-motor-driven double-mass vibration system in the x and ψ directions; f1, f 2y are respectively the damping coefficient of the inner mass and the outer mass in the y direction; is the first-order time derivative; is the second-order time derivative.

2. The method according to claim 1, wherein, The relative motion differential equation of the inner mass and the outer mass in the y direction is established as follows:

3. The method according to claim 1, wherein, The following is set: According to the first two equations in formula (1), the relative motion differential equation of the inner mass and the outer mass in the y direction is obtained as follows: 1) The masses of the two excitators are identical, i.e. m 01 = m 02 = m0; 2) the average phase of the two exciters is The phase difference is α, which satisfies 3) The average angular velocity of the two exciters in the double-motor double-mass vibration system is set as ω m0 ; 4) When the dual-motor dual-mass vibration system is synchronously operated, the formula (1) is omitted and 5) stiffness k of the vibration isolation spring (4) in the x direction 2x and in the y direction k 2y less than k1; 6) damping coefficient f 2y is 0; In formula (2) By considering formula (2), the inherent frequency ω0 of the relative motion of the inner mass and the outer mass in the x direction is obtained, which is regarded as the inherent frequency of the main vibration system, and the main vibration system comprises the inner mass (6), the outer mass (7), the shear spring (3) and the two exciters (1); y 12 = y1 - y2, M'1 = M1, wherein M In is the induced mass of the double-motor double-mass vibration system; y 12 is the relative displacement of the endoplasm and ectoplasm in the y direction; The relative motion of the inner mass and the outer mass in the y direction is rewritten as follows: Wherein, According to the mathematical solution of the extremum principle, the response amplitude of the opposite phase relative motion is represented as: When z0= 1, i.e. ω m0 = ω0, the maximum value of R 12 in equation (4) is obtained at the resonance point; the natural frequency ω0of the primary resonant system is the natural frequency of the in-phase relative motion of the endoskeleton and the exoskeleton in the y direction. The synchronization condition is determined as follows; 4. The method according to claim 1, wherein, For the first two equations of formula (1), the transfer function method based on Laplace transform is adopted, and the displacement response of the inner mass and the outer mass of the main vibration system in the x direction, the y direction and the ψ direction is represented as: According to the first two equations in formula (1), the characteristic equation of the inner mass and the outer mass in the y direction and the two inherent frequencies are obtained as follows: wherein τ c1 = k1, τ d = ω m0 f1, Wherein, Wherein, b = [M1(k1+k 2y )] 2 +(M2k1) 2 +2M1M2k1(k1-k 2y ) Combining equation (5), ignoring k 2y , we get ω Inv = ω0, ω Inv and ω Sa are the natural frequencies of the inner and outer pistons in the y direction with opposite and in-phase phases, respectively. When the two exciters (1) can reach a stable synchronous state, i.e. Differentiating x, y2and ψ in equation (6) with respect to time t, we get and Substituting them into the last two equations of equation (1), and Taking the mean value of the above integral, we get the average equilibrium equation of the two exciters (1) as follows: T e01 -d f1 -f d1 ω m0 = 0 (9) T e02 -d f2 -f d2 ω m0 = 0 (10) Formula (9) and formula (10) are arranged as W cc defined as dimensionless coupling coefficient, T e0j is the electromagnetic torque of the induction motor when the double-motor double-mass vibration system is running synchronously and stably, j = 1, 2; In formula (12), according to |sin(2α)|≤1, the synchronization criterion of the two exciters is obtained as follows (T e01 +T e02 )-(f d1 +f d2 )ω m0 =T L (11) where T L = d f1 + d f2 , T D = T R1 - T R2 , T R1 = T e01 - f d1 ω m0 , T R2 = T e02 - f d2 ω m0 ; where T L is the total load on both motors; T Rj is the effective electromagnetic output torque of motor j, j = 1, 2; T D is the difference in effective electromagnetic output torque of the two motors; T C is the frequency capture torque; The theoretical basis for the double-motor-driven double-mass vibration system to realize synchronous operation is described as follows: the absolute value of the difference between the effective electromagnetic output torques of the two motors should be less than or equal to the frequency capture torque; according to the above analysis, the prerequisite for the double-motor-driven double-mass vibration system to realize synchronization is that the frequency capture torque is sufficient to overcome the difference between the two motors, and then the phase difference is adjusted through energy distribution between the exciters to realize synchronization; |T D |≤T C (13) The stability condition is determined as follows, When the two shaker parameters are exactly the same, then T D = T R1 - T R2 = 0; according to equation (12), the phase difference of the two shakers stabilizes at 0 or π; define the synchronization ability coefficient ζ between the two shakers, i.e. In formula (14), ζ is a nonlinear function of ω m0 .

5. The parameter determination method of the double-motor-driven energy-saving horizontal oval vibration screen according to claim 4, characterized in that, The average motion amount of Hamilton in a period is represented as I, which is represented as In formula (12) There are two solutions, according to Hamilton's principle to study the stability of the synchronous state, the kinetic energy T and potential energy V of the whole double-motor double-mass vibration system are shown as follows; In the formula, H is the stability ability coefficient; Solution of stable phase difference in synchronous state corresponding to the minimum point of I, and thus the second derivative with respect to I is positive, i.e., Substituting formula (17) into (18), the stability criterion of the double-motor-driven double-mass vibration system is given by the following formula ​ wherein According to formula (19), the stability criterion requires that the product of the stability capability coefficient H and the cosine value of the phase difference of the two excitators is greater than 0; the parameter H is used to measure the stability of the system, and the greater the value, the stronger the stability capability of the double-mass vibration system driven by the double machines; in order to meet the stability criterion, when H>0; when H<0.

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