RU170737U1 - SHOCK ABSORBER FOR EXTINGUISHING RESONANCE VIBRATIONS IN VIBRATION MACHINES - Google Patents

Abstract

The utility model relates to the field of mechanical engineering and can be used to damp resonance vibrations in vibrating machines. The objective of the claimed utility model is to reduce the magnitude of the resonant vibrations of a vibrating machine with a slight decrease in its working vibrations. The shock absorber for damping resonance vibrations in vibrating machines contains a cylinder in which a rod guide with a hydraulic piston is located, a hydraulic cavity filled with a working fluid and divided by a hydraulic piston into lower and upper hydraulic parts connected by channels, a gas cavity separated from the lower hydraulic part pneumatic piston; hydraulic sleeve fixedly mounted inside the cylinder. The shock absorber is equipped with an additional hydraulic and centering bushings fixedly mounted inside the cylinder, the additional hydraulic sleeve being made with an inner diameter greater than the diameter of the hydraulic piston by two to five millimeters, and the centering sleeve is made with four equally symmetrical holes and with a central hole with a diameter larger than the diameter the hydraulic piston rod by one millimeter, while the hydraulic bushings are spaced a distance greater than their height n value equal to double the amplitude of vibration of the working machine, the hydraulic piston is identical with eight grooves symmetrically disposed at each end of the piston, the lower end of the hydraulic piston rod disposed within the central bore of the centering sleeve and protrudes beyond it.

Description

The utility model relates to the field of mechanical engineering and can be used to damp resonance vibrations in vibrating machines during start-up and braking.

Most of the vibrating transport-technological machines operate in the resonance zone of oscillations. Therefore, during acceleration and braking there is a sharp increase in the amplitude of the oscillations (ten or more times), which increases the dynamic load on the machine and thereby reduces their resource.

The shock absorber must have two operating modes:

- operating mode - with a low coefficient of resistance for insignificant influence on the operating oscillations and minimization of power losses due to vibration;

- starting braking mode - with a high coefficient of resistance to damp resonant oscillations, and the resistance should increase in proportion to the amplitude of the oscillations.

The shock absorber should also have a long resource, namely, a service life of at least 1 year, and about 300 million oscillations will be committed (based on the oscillation frequency of 50 Hz).

One-tube and two-tube automobile shock absorbers are known (Shock Absorber Designs / Dobromirov V.N., Ostretsov A.V. - M .: MGTU "NAMI" - 2007, pp. 16-23) containing a cylinder, a piston rod with bypass holes and valves, hydraulic and pneumatic cylinder cavities separated by a piston (single-tube) or walls of the inner cylinder (two-pipe). Shock absorbers provide a smooth ride and dampen vibrations with a large amplitude when driving on rough roads.

The disadvantages of these shock absorbers, from the point of satisfaction of the requirements presented above, are the high coefficient of resistance due to the strong friction of the piston against the cylinder walls and the high hydraulic resistance of the valves. And also a low resource, however, like all automobile shock absorbers, designed for about 10 million vibrations (from the calculation of the oscillation frequency of 1 ... 3 Hz).

Known shock absorber according to the patent of the Russian Federation No. 2304053, publ. 08/10/2007 according to the IPC indices B60G 17/04, F16F 9/512. The shock absorber comprises a cylinder, a piston, a rod, a hydraulic cavity filled with a working fluid and divided by a piston into lower and upper parts connected by channels, as well as valves with elastic elements and a control device associated with the electric motor. The electric motor is mounted on the outer stem of the stem. The rotor of the electric motor, which is functionally its anchor, is connected to the regulating element in the form of a spool placed in the stem and having the ability to rotate in it. The motor housing, which performs the function of an inductor (magnetic field source) with permanent magnets, is mounted motionless on the outer stem of the rod. In order to ensure the supply of current to the armature winding, which has the ability to rotate, the electric motor is equipped with a current collector.

Disadvantages of the shock absorber: design complexity, the presence of an electric motor that complicates installation, high coefficient of resistance.

Known shock absorber according to the patent of the Russian Federation No. 2269703, publ. 02/10/2006 by the IPC indices F16F 9/06, F16F 9/012. The shock absorber contains a rod, gas and hydraulic cavities and is equipped with an impeller mounted on the rod with the possibility of rotation around its axis, dividing the hydraulic cavity into upper and lower parts and consisting of a sleeve, a retaining ring and curved blades located between them.

The disadvantages include:

- the complex design of the shock absorber;

- high coefficient of resistance, as in the previous design of the shock absorber.

Known shock absorber according to the patent of Russian Federation No. 2286491, publ. 10/27/2006 by the IPC indices F16F 6/00, F16F 9/34. The shock absorber contains a housing, a rod and two rows of permanent magnets mounted on the rod and consisting of two piston halves with channels connecting the upper and lower parts of the hydraulic cavity. Between the halves of the piston there is a winding of an electromagnet made in the form of a closed loop. The spring-loaded core of the electromagnet is made in the middle part of the piston in the form of a double-sided gear rack meshed with two gears and connected through them to ring sectors equipped with throttling holes and designed to change the throughput of the piston channels. Two rows of permanent magnets are placed on the outer surface of the housing and facing each other with opposite poles.

The disadvantages include:

- the complex design of the shock absorber;

- high coefficient of resistance, as in the previous design.

The closest analogue is a single-tube hydropneumatic shock absorber with a rebound buffer, designed for installation on a car suspension (RF patent No. 2279582, published on July 10, 2006 according to the IPC index F16F 9/06). The shock absorber contains a cylinder, a rod with a working piston, a pneumatic piston-separator, a rod guide and a throttling system, a hydraulic sleeve fixedly mounted in the housing, and a hydraulic piston with grooves mounted on the rod. In the space between the hydraulic sleeve and the rod guide, a cavity of the hydraulic rebound buffer is formed, filled with liquid from the working cavity of the shock absorber.

The shock absorber of the prototype is simpler in construction than the described analogues, but does not provide a small coefficient of resistance due to the strong friction of the piston against the cylinder walls and low throughput of the channels, moreover, a decrease in the rigidity of shock loads occurs only during rebound.

The objective of the claimed utility model is to reduce the magnitude of the resonant vibrations of a vibrating machine with a slight decrease in its working vibrations.

The problem is solved due to the fact that the shock absorber for damping resonance vibrations in vibrating machines, comprising a cylinder in which a rod guide with a hydraulic piston are located, a hydraulic cavity filled with a working fluid and divided by a hydraulic piston into lower and upper v hydraulic parts interconnected channels, a gas cavity separated from the lower hydraulic part by a pneumatic piston, a hydraulic sleeve fixedly mounted inside the cylinder, while the hydraulic The piston is made with grooves, unlike the prototype, it is equipped with an additional hydraulic and centering bushings fixedly installed inside the cylinder, the additional hydraulic bush made with an inner diameter greater than the diameter of the hydraulic piston by two to five millimeters, and the centering bush made with four identical symmetrically arranged holes and with a central hole with a diameter larger than the diameter of the piston rod by one millimeter, while the hydraulic bushings spaced a distance greater than their height by an amount equal to the double working amplitude of the vibrating machine, the hydraulic piston is made with eight equal grooves symmetrically located at each end of the piston, while the lower end of the piston rod is located inside the central hole of the centering sleeve and protrudes beyond it.

The essence of the claimed utility model is illustrated by drawings, where:

- in FIG. 1 schematically shows a General view of the shock absorber;

- in FIG. 2 presents a view In the centering sleeve along the longitudinal axis of the inventive device shock absorber;

- in FIG. 3 shows a view G of a hydraulic piston with grooves along the longitudinal axis of the inventive damper device;

- in FIG. 4 schematically shows a shock absorber on a vibrating machine.

The shock absorber for damping resonance vibrations in vibrating machines contains a cylinder 1, in which there is a guide 2 of the rod 3 with a hydraulic piston 4. On both sides of the hydraulic piston 4 there are hydraulic bushings 5 and 6, the inner diameter of which is two to eight more than the diameter of the hydraulic piston 4 millimeters for their free movement inside the hydraulic bushings 5 and 6. The rod 3 of the hydraulic piston 4 passes through the Central hole of the centering sleeve 7. The centering sleeve 7 is made with four symmetrical spaced holes. The presence of four holes in the centering sleeve 7 provides free flow of the working fluid through the sleeve 7. The pneumatic piston 8 divides the inner space of the cylinder 1 into hydraulic A and gas B parts. As a gas, neutral nitrogen can be used at a pressure of 0.5-2.0 MPa. The hydraulic part A is filled with a working fluid that provides the required value of the coefficient of resistance of the shock absorber. As the working fluid, a special fluid for automobile shock absorbers, for example AZh-12T, can be used. The hydraulic piston 4 is made with eight identical grooves 9, symmetrically located at each end of the piston 4. The number, profile and dimensions of the grooves 9 of the hydraulic piston 4 determine the progressive characteristic of the resistance of the hydraulic buffer of the rebound (or compression) at the end of the rebound (or compression) of the shock absorber, and also contribute to a more free movement of the piston 4 during operating vibrations compared to a hydraulic piston without grooves.

The shock absorber is as follows.

Shock absorbers 10 are installed between the oscillating 11 and the base 12 parts of the vibrating machine. The vibrations are excited by the vibrator 13. The springs 14 support the vibrating part 11 of the vibrating machine. The operating mode of the vibrating machine is influenced by: the exciting force F _{0 of the} vibrator 13 and its angle of inclination β, the stiffness from the springs 14. In the operating mode of the vibrating machine, the oscillatory movement of the hydraulic piston 4 occurs outside the hydraulic bushings 5 and 6. In this mode, the resistance to the movement of the rod 3 due to frictional forces at its contact with the piston guide 2 and the centering sleeve 7; the force of hydraulic friction from the free movement of the rod 3 with a hydraulic piston 4 inside the cylinder 1; the inertia force of the rod 3 with a hydraulic piston 4. The coefficient of resistance of the shock absorber 10 in this mode is minimal.

At the moments when the vibrating machine starts and stops, resonant oscillations arise with an amplitude that exceeds the working amplitude by approximately an order of magnitude (ten times) (this would be the case in the absence of shock absorbers). But, as soon as the amplitude exceeds twice the magnitude of the working amplitude, the hydraulic piston 4 will go inside the hydraulic sleeve 5 or 6, depending on the direction of the resonant vibrations, which will push the working fluid through the grooves 9 of the piston 4 and the resulting gaps between the sleeve 5 or 6 and the hydraulic 4. piston accompanied by a relatively sharp increase in hydraulic resistance. The coefficient of resistance of the shock absorber will increase proportionally. 10. The amplitude of the resonant oscillations will be reduced.

The required coefficient of resistance of the shock absorber 10 is set according to the difference between the internal diameter of the hydraulic bushings 5 and 6 and the diameter of the piston 4, as well as the number and shape of the grooves 9. The amplitude limit value is set according to the difference between the height of the hydraulic bushings 5 and 6 and the height of the hydraulic piston 4. Guide 2 and the centering sleeve 7 are used to direct the movement of the rod 3 strictly along the axis of the cylinder 1. The holes in the centering sleeve 7 provide unhindered movement of the working fluid in the adjacent s inner space of the cylinder 1. A pneumatic piston 8 compensates for variation in the internal volume of the hydraulic chamber A when the stem 3 motion due to compression of the gas-expansion chamber B.

Thus, the claimed design of the shock absorber allows you to freely implement the operating mode of the vibrating machine, without limiting the amplitude of the operating vibrations, and at the same time provides damping of the resonant vibrations that occur during start-up and shutdown of the machine, provided that the working amplitude is more than doubled, thereby increasing the resource vibration transport and technological machine.

Claims (1)

A shock absorber for damping resonance vibrations in vibrating machines, comprising a cylinder in which a rod guide with a hydraulic piston is located, a hydraulic cavity filled with a working fluid and divided by a hydraulic piston into lower and upper hydraulic parts connected by channels, a gas cavity separated from the lower hydraulic parts by a pneumatic piston, a hydraulic sleeve fixedly mounted inside the cylinder, while the hydraulic piston is made with grooves, characterized the fact that it is equipped with an additional hydraulic and centering bushings fixedly installed inside the cylinder, the additional hydraulic sleeve is made with an inner diameter greater than the diameter of the hydraulic piston by two to five millimeters, and the centering sleeve is made with four equally symmetrically arranged holes and with a central hole with a diameter, large diameter of the piston rod by one millimeter, while the hydraulic bushings are spaced a distance greater than their height over Ichin equal to double the amplitude of vibration of the working machine, the hydraulic piston is identical with eight grooves symmetrically disposed at each end of the piston, the lower end of the hydraulic piston rod disposed within the central bore of the centering sleeve and protrudes beyond it.

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