RU170565U1 - 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 during start-up and braking. The objective of the claimed utility model is to reduce the coefficient of resistance of the shock absorber at small values of the amplitude of the vibrations corresponding to the operating mode of the vibrating machine, providing a jump-like increase in the coefficient of resistance when the specified value of the amplitude of the oscillations is reached. A shock absorber for damping resonance vibrations in vibrating machines, comprising a cylinder inside which a rod with a hydraulic piston is located, a hydraulic cavity filled with a working fluid and separated by a hydraulic piston into lower and upper hydraulic parts connected by channels, a gas cavity separated from the lower hydraulic part pneumatic piston, characterized in that it is additionally equipped with a hydraulic and centering sleeves, fixedly mounted inside the cylinder, and the hyd The bushing has an inner diameter larger than the diameter of the hydraulic piston by two to eight millimeters, and the centering sleeve is made with four symmetrically arranged holes and with a central bore diameter larger than the diameter of the piston rod by one millimeter, while the hydraulic piston is double and its parts are spaced at a distance greater than the width of the hydraulic sleeve by an amount equal to the double working amplitude of the vibrating machine, the lower end of the piston rod is located ene inside the central hole and the centering sleeve 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 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 to minimize power losses due to vibration;

- start-brake mode - with a high coefficient of resistance for damping resonance oscillations, and the resistance should increase stepwise when reaching the specified value of the amplitude of the oscillations.

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

Single-tube and two-tube automobile shock absorbers are known (I. Reimpel. Car chassis. Shock absorbers, tires and wheels. M .: Mechanical Engineering, 1986), containing a cylinder, a piston rod with bypass holes and valves, hydraulic and pneumatic cylinder cavities separated by a piston (single-tube ) or the 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, in terms of meeting the above requirements, 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, as well as the low resource, however, like all automobile shock absorbers, designed for about 10 million vibrations (from calculation of the oscillation frequency 1 ... 3 Hz).

Known shock absorber according to the patent of the Russian Federation No. 2304053, IPC B60G 17/04, F16F 9/512, publ. 08/10/2007. 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 shock absorber 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.

Design disadvantages:

- the complex design of the shock absorber;

- the presence of an electric motor that complicates installation;

- high coefficient of resistance.

Known shock absorber (RF patent No. 2253576, IPC B60G 17/04, F16F 9/512, publ. 06/10/2005) containing a cylinder, piston, rod, hydraulic cavity filled with a working fluid and divided by a piston into the lower and upper parts connected between channels, as well as valves with elastic elements and a control device associated with an electric motor. 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 (source of a magnetic field) with permanent magnets, is mounted motionless on the shaft end. 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.

The disadvantages include:

- the complex design of the shock absorber;

- the presence of an electric motor that complicates installation;

- high coefficient of resistance.

The closest analogue to the claimed utility model is a single-tube hydropneumatic shock absorber for the rear suspension of the car [Shock absorbers. Design, calculation, testing / Dobromirov V.N., Gusev E.N., Karunin M.A., Khavkhanov V.N. - M.: MSTU "MAMI" - 2006, 184 p. Page 17, fig. 1.5]. The shock absorber contains a cylinder, a rod, a hydraulic cavity filled with a working fluid and separated by a hydraulic piston into lower and upper parts connected by channels, and equipped with compression and rebound valves, a gas cavity separated from the lower hydraulic part by a pneumatic piston.

The shock absorber of the prototype is simple in design, but does not fully satisfy the above requirements, namely it does not provide:

- low coefficient of resistance in the operating mode of the vibrating machine due to the strong friction of the hydraulic piston against the cylinder walls and the low throughput of the channels;

- abrupt increase in the coefficient of resistance upon reaching the set value of the amplitude of the oscillations due to the lack of a clearly defined transient mode of operation.

The objectives of the claimed utility model are:

- reducing the coefficient of resistance of the shock absorber at small values of the amplitude of the oscillations corresponding to the operating mode of the vibrating machine, by reducing the friction force between the hydraulic piston rod and the cylinder walls and increasing the channel capacity;

- providing a jump-like increase in the drag coefficient upon reaching the set value of the oscillation amplitude due to the additional supply of the shock absorber with a hydraulic sleeve and double execution of the hydraulic piston, with its parts spaced apart by a distance greater than the width of the hydraulic sleeve.

The problem is solved due to the inventive design of a shock absorber for damping resonance vibrations in vibrating machines, containing a cylinder inside which a rod with a hydraulic piston is located, a hydraulic cavity filled with a working fluid and separated by a hydraulic piston into lower and upper hydraulic parts connected by channels, gas a cavity separated from the lower hydraulic part by a pneumatic piston, in contrast to the prototype, the shock absorber is additionally equipped with a hydraulic and centering sleeves fixedly mounted inside the cylinder, the hydraulic sleeve having an inner diameter greater than the diameter of the hydraulic piston by two to eight millimeters, and the centering sleeve is made with four symmetrically arranged holes and with a central hole with a diameter larger than the diameter of the hydraulic piston rod by one millimeter, with the hydraulic piston is double and its parts are spaced a distance greater than the width of the hydraulic sleeve by an amount equal to the double working amp In the center of the vibrating machine, the lower end of the hydraulic piston rod is located inside the center 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 shows a view of a centering sleeve along the longitudinal axis of the shock absorber;

- in FIG. 3 schematically shows the installation of 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 rod 2 with a double hydraulic piston, consisting of identical parts of the upper 3 and lower 5 cylindrical shape. Between the upper part 3 and the lower part 5 of the hydraulic piston there is a hydraulic sleeve 4, the inner diameter of which is greater than the diameter of the upper 3 and lower part 5 of the hydraulic piston by two to eight millimeters for their free movement inside the hydraulic sleeve 4. The upper 3 and lower 5 parts of the hydraulic piston located at a distance from each other greater than the width of the hydraulic sleeve 4 by an amount equal to the double working amplitude of the vibrating machine, and the lower part 3 is located at a distance from the centering sleeve 6 greater than the possible amplitude of the resonant oscillations. The lower end of the rod 2, located under the lower part 5 of the hydraulic piston, is located inside the central hole of the centering sleeve 6 and protrudes beyond it. The centering sleeve 6 is made with four symmetrically located holes. The presence of four holes in the centering sleeve 6 provides free flow of the working fluid through the sleeve 6.

Pneumatic piston 7 divides the inner space of cylinder 1 into gas part A and hydraulic B, in which there are hydraulic 4 and centering 6 bushings, a double hydraulic piston with a rod 2. Neutral nitrogen can be used as gas under pressure of 0.5-2.0 MPa The hydraulic part B is filled with a working fluid that provides the required value of the coefficient of resistance of the shock absorber. As a working fluid, a special fluid for automobile shock absorbers can be used.

The shock absorber for damping resonance vibrations in vibrating machines is as follows.

Shock absorbers 8 are installed between the vibrating 9 and the base 10 parts of the vibrating machine to ensure plane-parallel movement of the vibrating part 9 with respect to the base part 10. The vibrations in the vibrating machine are excited by a vibrator 11 mounted on the vibrating part 9. The springs 12 connect the oscillating 9 and the base 10 to each other. parts of a vibrating machine. The operating mode of the vibrating machine is influenced by: the exciting force F _{0 of the} vibrator 11 and its angle of inclination β, the stiffness from the springs 12.

In the operating mode of the vibrating machine, the oscillatory movement of parts 3 and 5 of the hydraulic piston occurs outside the hydraulic sleeve 4. In this mode, the resistance to the movement of the rod 2 is due to the frictional force at the point of contact with the cylinder 1; the force of hydraulic friction from the free movement of the moving parts of the shock absorber 8 inside the cylinder 1; the inertia force of the moving parts of the shock absorber 8; the gas compression force in the gas part A of cylinder 1. The shock absorber resistance coefficient 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 about an order (ten times) in the absence of shock absorbers. But, as soon as the amplitude exceeds twice the magnitude of the working amplitude, both parts 3 and 5 of the hydraulic piston will enter the inner hole of the hydraulic sleeve 4, which will cause the fluid to push through the gaps between the internal hole of the hydraulic sleeve 4 and parts 3 and 5 of the hydraulic piston, accompanied by a sharp increase in hydraulic resistance. The coefficient of resistance of the shock absorber will increase proportionally. The amplitude of the resonant oscillations will be reduced.

The required coefficient of resistance of the shock absorber is set according to the difference between the inner diameter of the hydraulic sleeve 4 and the diameter of parts 3 and 5 of the hydraulic piston. The magnitude of the limitation of the amplitude of the resonant vibrations is set by the difference between the width of the hydraulic sleeve 4 and the distance between parts 3 and 5 of the hydraulic piston. Also, the pressure coefficient in the gas part A affects the coefficient of resistance of the shock absorber.

The centering sleeve 6 serves to direct the movement of the rod 2 strictly along the axis of the cylinder 1. The presence of a gap of 1 mm between the center hole of the centering sleeve 6 and the rod 2 virtually eliminates friction between them, because mating rod-centering sleeve are of the "sliding fit" type. The holes in the centering sleeve 6 provide unimpeded movement of the working fluid in the adjacent inner space of the cylinder 1.

The pneumatic piston 7 compensates for the change in the internal volume of the hydraulic cavity B during the movement of the rod 2 due to compression-expansion of the gas part A.

Thus, the claimed constructive design of a shock absorber for damping resonance vibrations in double-acting vibration machines with a double piston allows the operating mode of a vibrating machine with a low drag coefficient to minimize power losses due to vibration and a brake starting mode - with a high drag coefficient for damping resonant vibrations, and the resistance increases spasmodically when the specified value of the amplitude of oscillations is reached.

Claims (1)

A shock absorber for damping resonance vibrations in vibrating machines, comprising a cylinder inside which a rod with a hydraulic piston is located, a hydraulic cavity filled with a working fluid and separated by a hydraulic piston into lower and upper hydraulic parts connected by channels, a gas cavity separated from the lower hydraulic part pneumatic piston, characterized in that it is additionally equipped with a hydraulic and centering bushings, fixedly mounted inside the cylinder, and the hydraulic sleeve has an inner diameter greater than the diameter of the hydraulic piston by two to eight millimeters, and the centering sleeve is made with four symmetrically arranged holes and with a central hole with a diameter larger than the diameter of the hydraulic piston rod by one millimeter, while the hydraulic piston is double and its parts are spaced at a distance greater than the width of the hydraulic sleeve by an amount equal to the double working amplitude of the vibrating machine, the lower end of the piston rod is dix within the central opening and centering sleeve protrudes beyond it.

Images