RU2604005C1 - Vibration grinder - Google Patents

Abstract

FIELD: vibration equipment.

SUBSTANCE: invention relates to vibration equipment and can be used for lumps and loose materials grinding and milling. Vibration grinder comprises working member, means of resonant progressive circular oscillations communication to which is isotropic resilient suspension in form of cylindrical rods, by which it is connected to fixed base, and rotary pendulum exciter driven to rotation in vertical plane by drive shaft. Resonance tuning of resonant progressive circular oscillations communication devices is defined by resonance combination parametric relationship ω = λ₁+ λ₂, where ω is parametric excitation frequency (rotary pendulum exciter speed), λ₁ = vω is pendulums oscillations partial natural frequency, v - dimensionless parameter determining pendulums oscillations partial natural frequency in rotary coordinates system (0<v<1), $${\lambda }_2={\lambda }_{2x}={\lambda }_{2y}=\sqrt{C/M_0}$$

is working element partial natural frequency corresponding to vibrations circular shape, C = C_x = C_y is isotropic resilient rod suspension rigidity, M₀ is machine working member weight.

EFFECT: higher quality of raw material grinding.

1 cl, 3 dwg

Description

The invention relates to vibration technology and can be used in all industries for grinding, grinding lump and bulk materials. The scope of the invention is very wide: production of building materials, grinding and activation of low-grade cement, the production of fine-ground products for the glass and food industries; production of grinding powders, obtaining fine, ultrafine materials and nanopowders to ensure the production of magnetorheological suspensions, etc.

 The general name Vibratory Grinding Machine (VIM) refers to a group of machines: vibration mills, vibration mixers, vibration grinders, etc.

Centrifugal (unbalanced), kinematic, electromagnetic, electrodynamic, hydraulic and pneumatic exciters are used as a VIM drive.

Modern VIMs, as a rule, operate in a forced oscillation mode with a far resonant frequency. This mode is accompanied by irrational energy consumption, which leads to an increase in energy consumption. In addition, the reliability of the drive is reduced as a result of the action of large inertial forces. Tuning such machines to a resonant (energy-saving) mode of forced oscillations is not possible. This is explained by the steepness of the amplitude-frequency characteristic, the small value of the resonance zone, and low stability. Therefore, even small changes in the technological load bring the machine out of resonance mode.

Small distribution in VIM received electromagnetic vibration exciters. The advantage of such drives is the ease of tuning the resonant mode of oscillation. But in view of the small disturbing force developed by electromagnetic pathogens, relatively small vibration amplitudes arise that are not able to carry out the grinding process [Vibrations in technology in 6 volumes. T.4. Vibration processes. M .: Engineering, 1981. p. 258. Shishkanov K.A., Dmitrak A.Yu. Analysis of the designs and main characteristics of vibration mills // Mining Information and Analytical Bulletin (scientific and technical journal). 2011. No4, p. 324-328].

Currently, modern designs of resonant VIM include unbalanced vibration exciters, which drive the grinding chamber with technological loading into vibrational motion [Lesin A.D. Modern grinding equipment. Vibratory Mills. Overview information. Series 7. Industry of non-metallic and non-metallic materials. - M .: VNIIESM, 1989. p. 43].

The disadvantage of this design is the resonance tuning of high frequency and low amplitude. This leads to high unproductive energy consumption, low grinding efficiency, reduced reliability of the drive. To increase the grinding efficiency, it is necessary to increase the amplitude of vibrations and reduce their frequency to obtain intense destructive influences. The issue of reducing energy costs is solved on the basis of the development of resonant machines. Improving the grinding efficiency, the reliability of the drive while reducing energy costs can be achieved by using parametric vibration exciters in which Raman parametric resonance is realized [Antipov V.I. Vibration exciter: Patent No. 2072661 of the Russian Federation, MKI V06V 1/16 // Bull. No. 3, 1997. Antipov V.I., Dentsov N.N., Koshelev A.V. Energy ratios in a vibrating machine using multiple Raman resonance resonance // Bulletin of the Nizhny Novgorod State University. N.I. Lobachevsky. 2013. - No. 5. - S. 188-194] in conjunction with an isotropic elastic suspension [Antipov V.I., Dentsov N.N., Koshelev A.V. Dynamics of a parametrically excited vibration machine with an isotropic elastic system // Fundamental Research. 2014. - No. 8, part 5. - S. 1037-1042].

As a prototype adopted vibration mill containing a pair of cylindrical grinding chambers with grinding bodies in a housing mounted on elastic supports. The causative agent of oscillations of the resonance frequency is the unbalanced vibration exciter installed between the grinding chambers [Patent No. 2302904 В02С 19/00, Bull No. 20, 2007].

The disadvantages of this device are:

• The out-of-resonance mode of operation is accompanied by a small amplitude of oscillations, which does not allow obtaining large destructive effects. As a result, the process time is increased and productivity is reduced.

• To achieve the resonance region, it is necessary to have an engine power that is 5 times higher than the power needed to maintain the resonance oscillations.

• The resulting large centrifugal forces, due to the rotation of the unbalances, load the bearings, which leads to a decrease in their durability and an increase in energy consumption.

• The need to take into account motor overloads in starting mode. This forces the use of centrifugal vibrator electric motors, the power of which is 1.5-2 times higher than necessary in the steady state.

• The presence of spurious oscillations destabilizes the operating mode and causes additional energy dissipation.

The objective of the invention is to solve these shortcomings while improving the quality and performance of the machine.

The technical result of the invention is the fine grinding of materials with increased productivity, reducing centrifugal forces, reducing spurious vibrations.

- парциальная собственная частота рабочего органа, соответствующая круговой форме колебаний, C=C_x=C_y - жесткость изотропной стержневой упругой подвески, M₀ - масса рабочего органа машины.The technical result of the claimed VIM is achieved by the fact that in a vibration grinding machine containing a working body, the means for communicating resonant translational circular vibrations of which are an isotropic elastic suspension in the form of cylindrical rods, which it is connected to a fixed base, and a rotary-pendulum exciter driven into rotation in the vertical plane of the drive shaft, and the resonant tuning means for communicating resonant translational circular oscillations is determined from the ratio I Raman parametric resonance ω = λ ₁ + λ _2, where ω - frequency parametric excitation (speed rotary pendulum pathogen), λ ₁ = νω - partial natural frequency of the pendulum swing, ν - dimensionless parameter which determines the natural frequency of oscillations of the pendulums in the rotating coordinate system (0 <ν <1), $${\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="00000014.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2={\lambda }_{2x}={\lambda }_{2y}=\sqrt{C/M_0}$$

is the partial eigenfrequency of the working body corresponding to the circular form of vibration, C = C _x = C _y is the stiffness of the isotropic rod elastic suspension, M ₀ is the mass of the working body of the machine.

A diagram of a vibratory grinding machine is shown in FIG. 1, 2. The working body 1 rests on a fixed base 2 by means of an isotropic rod elastic system 3 of rigidity C (Fig. 1). A pair of cylindrical grinding chambers 4 with grinding bodies 5 of a spherical shape (balls), between which a parametric drive 6 (a parametric motor-vibrator) is installed, is mounted on the working body to excite and maintain resonant translational circular vibrations. It is an electric motor, on the shaft of which a rotary-pendulum exciter is installed, the plane of rotation of which is located in a vertical plane.

Resonant vibrations at a frequency of λ ₂ are taken as working, corresponding to translational circular vibrations of the working body of the machine in two mutually perpendicular directions along the axes Ox, Oy. According to Widler’s postulate, it is assumed here that the form of stationary resonant oscillations coincides with the form of free vibrations.

In FIG. 2 shows a diagram of the rotary-pendulum pathogen of a parametric drive [Antipov V.I. Vibration exciter: Patent No. 2072661 of the Russian Federation, MKI B 06 V 1/16 // Bull. No. 3, 1997]. The rotor of a parametric drive may consist of one rotary-pendulum exciter, as shown, or a set of such devices. In addition, a more efficient design of the rotor-pendulum pathogen can be used [V. Antipov. Vibration exciter: Patent No. 2072660 of the Russian Federation, MKI B 06 V 1/16 // Bull. No. 3, 1997].

The balanced disk 7 (Fig. 2) of the rotary-pendulum pathogen has three periodically alternating closed treadmills 8 of a circular profile, the centers of which are offset from the axis of rotation of the disk by equal distances AB = l. On treadmills are placed the same balanced rolling bodies (pendulums) 9 of mass m each with the possibility of running-in. The rotor-pendulum pathogen contains N = 3 rolling elements. Drive mass m ₀ in the assembled state is rigidly secured to the motor shaft, which is mounted on the end effector 1 mass M _0, which has two degrees of freedom: the translational motion x, y along the circular path of the rotor rotation plane in a direction Ox, Oy axes. Preferred is the design of the grinding machine with an electric motor removed from the oscillating system.

с началом в центре масс роторно-маятникового возбудителя движется поступательно по круговой траектории относительно неподвижной системы $$Oxyz$$

. При этом плоскость $$A{x}^{\prime }{y}^{\prime }$$

расположена в плоскости вращения ротора. В положении статического равновесия оси этих координатных систем совпадают. Ось z параллельна оси вращения диска.Coordinate system $$A{x}^{\prime }{y}^{\prime }{z}^{\prime }$$

with the beginning in the center of mass of the rotor-pendulum pathogen it moves progressively along a circular path relative to the stationary system $$Oxyz$$

. In this plane $$A{x}^{\prime }{y}^{\prime }$$

located in the plane of rotation of the rotor. In the position of static equilibrium, the axes of these coordinate systems coincide. The z axis is parallel to the axis of rotation of the disk.

The circular vibrations of the working body of the machine in the direction of the axes Ox, Oy are considered. This shape of the trajectory is ensured by the formation of an isotropic elastic field by introducing elastic elements having the same stiffness in at least two mutually perpendicular directions. Such an elastic system can be made in the form of cylindrical rods made of spring-spring steel, for example, anti-roll bars of a vehicle suspension.

(k=1,2,3; N=3 - число маятников), а положение маятников определяется углами φ_k=A_kcos(ω₁t+2πk/N) (k=1,2,3). Качания маятников на углы φ_k (k=1,2,3), а так же перемещения x, y рабочего органа составляют степени свободы рассматриваемой колебательной системы машины. Эти величины принимаются за обобщенные координаты системы. Таким образом, представленная механическая система машины имеет пять степеней свободы, которую можно рассматривать как систему, состоящую из двух подсистем.The position of the treadmills is determined by the angles $${\psi }_k=\omega t+2\pi k/N,$$

(k = 1,2,3; N = 3 is the number of pendulums), and the position of the pendulums is determined by the angles φ _k = A _k cos (ω ₁ t + 2πk / N) (k = 1,2,3). Swinging pendulums to angles φ _{k (k} = 1,2,3), as well as the displacement x, y working body constitute degree of freedom vibrational system of the machine under consideration. These values are taken as the generalized coordinates of the system. Thus, the presented mechanical system of the machine has five degrees of freedom, which can be considered as a system consisting of two subsystems.

mρ_с - статический момент маятников, $$J_B=(J_{C_k}+m{r}^2)i^{-2}-$$

момент инерции тела качения относительно оси обкатки, J_Ck - момент инерции тела качения относительно оси, проходящей через его центр масс, r - радиус цапфы тела качения, $$i=r/{\rho }_c$$

- передаточное отношение обкатки тела качения к беговой дорожке, l = АВ, ρ_c=BC_k.The first subsystem is a working body associated with a fixed base of an isotropic elastic suspension. The second subsystem consists of three identical pendulums located in the field of centrifugal inertia forces having the same partial eigenfrequencies λ ₁ = νω in the rotating coordinate system Aξηζ. Here $$\nu =\sqrt{m{\rho }_{c}l/J_B},$$

mρ _s is the static moment of the pendulums, $$J_B=(J_{C_k}+m{r}^2)i^{-2}-$$

the moment of inertia of the rolling body relative to the running axis, J _Ck is the moment of inertia of the rolling body relative to the axis passing through its center of mass, r is the radius of the journal of the rolling body, $$i=r/{\rho }_c$$

- gear ratio of the rolling of the rolling body to the treadmill, l = AB, ρ _c = BC _k .

самовозбуждается многократный комбинационный параметрический резонанс, удовлетворяющий соотношению ω=ω₁+ω₂. Здесь ω₁=νω≈λ₁ - частота генерации осцилляторов роторно-маятникового возбудителя, которая близка к их собственной частоте качаний, ε = ν²Nμ /2 - коэффициент, пропорциональный отношению общей массы осцилляторов качения к массе всей системы, $${\mu }_0=m{\rho }_c/M_{0}l,$$

$${\tilde{n}}_0=n_0/{\lambda }_2,\tilde{n}=n/{\lambda }_2-$$

относительные коэффициенты линейного демпфирования соответственно осцилляторов качения и массы M_0. The device operates as follows. Energy is supplied to the vibrational system of the vibratory grinding machine due to the uniform rotation of the disk 7 of the rotor-pendulum exciter of the parametric drive 1 with an angular velocity ω. When setting ν = 0.25 and satisfying the threshold condition $$\epsilon >\mathrm{four}{\tilde{n}}_0\tilde{n}\nu /(\mathrm{one}-\nu )$$

multiple Raman parametric resonance self-excited, satisfying the relation ω = ω ₁ + ω ₂ . Here, ω ₁ = νω≈λ ₁ is the oscillation frequency of the rotor-pendulum exciter oscillators, which is close to their own oscillation frequency, ε = ν ² Nμ / 2 is a coefficient proportional to the ratio of the total mass of the rolling oscillators to the mass of the whole system, $${\mu }_0=m{\rho }_c/M_{0}l,$$

$${\tilde{n}}_0=n_0/{\mathrm{<figure-callout\; id="2"\; label="\lambda "\; filenames="00000014.png"\; state="\{\{state\}\}">\lambda </figure-callout>}}_2,\tilde{n}=n/{\lambda }_2-$$

relative coefficients of linear damping, respectively, of the oscillators of rolling and mass M _0.

колебаний рабочего органа 2 и меньше частоты вращения диска на 25%. Поскольку ω₂≈λ₂, то центробежная сила инерции «невидимого дебаланса» возбуждает резонансные колебания корпуса измельчительной машины по круговой траектории, а колебания корпуса, в свою очередь, возбуждают ударные и пульсирующие движения мелющих тел 3 по внутренней поверхности помольной камеры 4. В результате этого происходит вовлечение тел системы в коллективное резонансное взаимодействие. Разрушение материала происходит в кольцевом зазоре между помольной камерой и указанными пульсирующими телами внутри помольной камеры. В результате достигается самоуправляемое, самоорганизованное и самоподдерживаемое собственное движение машины.Self-synchronization of the oscillations of the pendulums 9 (Huygens effect) leads to the formation of imbalance (“invisible unbalance”), rotating with a frequency ω ₂ ≈λ ₂ , which is close to the natural frequency $${\lambda }_{}$$$${}_2=\sqrt{C/M_0}$$

oscillations of the working body 2 and less than the frequency of rotation of the disk by 25%. Since ω ₂ ≈λ ₂ , the centrifugal inertia force of the “invisible unbalance” excites resonant vibrations of the grinding machine body along a circular path, and the body vibrations, in turn, excite shock and pulsating movements of grinding media 3 along the inner surface of grinding chamber 4. As a result This involves the involvement of the bodies of the system in collective resonant interaction. The destruction of the material occurs in the annular gap between the grinding chamber and the indicated pulsating bodies inside the grinding chamber. As a result, a self-governing, self-organized and self-sustaining machine movement is achieved.

Currently, the development trends of VIM are a decrease in the frequency of oscillations while increasing their amplitude. This is explained by the most effective method of grinding, allowing to realize a single, but powerful destructive effects on the processed material. In the proposed machine, this problem is automatically solved by the original design of the rotor-pendulum exciter, which allows to reduce the frequency of the working body of the machine by 25% when setting ν = 0.25 and by 50% when setting ν = 0.5 while increasing its amplitude due to resonant mode.

. Его величина снижается в два раза по сравнению с использованием такого же возбудителя, но в вибрационных транспортирующих машинах, где необходимы однонаправленные колебания [Антипов В.И., Антипова Р.И., Кошелев А.В., Денцов Н.Н. Вибрационная транспортирующая машина. Патент №2532235 РФ, В06В, Бюл. №30, 2014 г.]. Такое обстоятельство позволяет снизить массу маятников ВИМ тоже в два раза, причем эффективность и интенсивность колебаний рабочего органа при этом не снизится. Это подтверждает целесообразное применение роторно-маятникового возбудителя в качестве вибрационного привода измельчительных машин с круговым движением рабочего органа.A significant advantage of using a rotary-pendulum exciter in vibration grinding machines with a circular movement of the working body is the threshold for the excitation of parametric resonant oscillations $$\epsilon >\mathrm{four}{\tilde{n}}_0\tilde{n}\nu /(\mathrm{one}-\nu )$$

. Its value is halved compared to using the same pathogen, but in vibrating transporting machines where unidirectional vibrations are needed [Antipov V.I., Antipova R.I., Koshelev A.V., Dentsov N.N. Vibratory conveying machine. Patent No. 2532235 of the Russian Federation, B06B, Bull. No. 30, 2014]. This circumstance makes it possible to reduce the mass of VIM pendulums by half as well, and the efficiency and intensity of oscillations of the working body will not decrease. This confirms the appropriate use of the rotor-pendulum pathogen as a vibration drive of grinding machines with a circular movement of the working body.

The simplicity and reliability of the proposed design, small dimensions and weight, high efficiency of the drive compared with the currently dominant vibration drives allow the proposed vibration grinding machine to be used as a laboratory, stationary or mobile industrial unit.

This invention was developed and created for the above stated reasons (Fig. 3). His tests, as well as the experiments conducted on him, confirmed reliable and stable operation.

The proposed resonant VIM has important advantages and advantages.

1. The efficiency of the rotor-pendulum pathogen is higher than analogues by 25%. The higher the efficiency, the lower the energy consumption. The required oscillation amplitude is achieved with a minimum static moment, which creates minimal load on the bearing assemblies of the drive shaft. As a result of this, the durability of bearings increases, their reliability and the energy consumption for overcoming friction is reduced. In addition, the operating resonant mode of operation of the VIM is characterized by high stability, which is unattainable when using conventional centrifugal vibration exciters.

2. The engine of the parametric drive of the grinding machine, unlike the kinematic or centrifugal, at the time of start-up overcomes only the moment of friction in the bearings, accelerates almost in idle mode, so there is no need to take into account the starting moments of the engine, takes care of possible engine overloads. This circumstance makes it possible to reduce the installation power of the VIM parametric vibration drive motor by more than two times in comparison with the centrifugal (unbalanced) vibration drives that prevail today.

3. High intensity of the process of grinding materials. The possibility of exciting large amplitudes of vibrations at low frequencies allows to obtain large destructive effects on the processed material. As a result, its residence time in the grinding chamber is reduced, which helps to increase the purity of the finished product and increase the productivity of the machine.

4. The presence of a rod isotropic elastic suspension allows to exclude the influence of spurious oscillations and to obtain the necessary form of vibrations of the working body of the machine. This helps to increase the level of energy saving and the efficiency of fine grinding due to the implementation of combined modes - impact and abrasion.

5. Convenience of operation and maintenance. Oscillations of the working body are excited only in the resonance region, near its natural frequency. In order to stop the grinding process, it is enough to remove the machine from the region of parametric resonance by increasing or decreasing the speed of rotation of the disk of the rotor-pendulum exciter, and not turn off the engine. In the non-resonant zone, the parametric drive does not oscillate, while the drive motor is running.

6. The lack of automatic means for monitoring the resonant frequency of oscillations, means for reducing the frequency of oscillations of the working body, as well as means for stopping the engine. This has a positive effect on the reliability, efficiency and cost of the machine.

The analysis shows that the proposed invention satisfies the three main criteria presented to it - “novelty”, “industrial applicability” and “inventive step”.

Claims (1)

A vibration grinding machine containing a working body, in which a pair of cylindrical grinding chambers with grinding bodies of a spherical shape is installed, characterized in that the device for exciting and maintaining stable working resonant modes of working body vibrations along a circular path is a parametric resonant rotor-pendulum exciter, and isotropic the elastic suspension of the working body is made of cylindrical rods of spring-spring steel, while the necessary form of oscillations of the working of the body is achieved isotropic elastic suspension, the resonance tuning is determined from the ratio of the combination of parametric resonance ω = λ ₁ + λ _2, where ω - frequency parametric excitation (speed rotary pendulum pathogen), λ ₁ = νω - partial natural frequency of the pendulum swing, ν is a dimensionless parameter that determines the natural frequency of the swing of the pendulums in a rotating coordinate system (0 <ν <1), $${\lambda }_2={\lambda }_{2x}={\lambda }_{2y}=\sqrt{C/M_0}$$

is the partial eigenfrequency of the working body corresponding to the circular form of vibration, C = C _x = C _y is the stiffness of the isotropic rod elastic suspension, M ₀ is the mass of the working body of the machine.

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