RU2120389C1 - Method of vibration damping and swirl hydraulic shock absorber - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: transport engineering. Vehicle vibration damping is provided by interaction of tangential correcting liquid flow in swirl hydraulic shock absorber with control of resistance to liquid flow in chamber. Shock absorber of proposed design features long service life, stability of characteristics and simple construction. EFFECT: enhanced damping. 10 cl, 5 dwg

Description

 The invention relates to methods for damping mechanical vibrations in vehicle suspensions and can be used to create damping elements of their suspension systems.

 A known method of damping oscillations by throttling a liquid under pressure through linear chokes [1].

 The disadvantage of this method is that when throttling it is impossible to obtain shock absorber characteristics other than straightforward.

 A known method of damping, using, in addition to throttling, energy dissipation in a vortex fluid flow [2,3,4]. This method allows you to get a progressive quadratic, most comfortable characteristic of the shock absorber.

 Moreover, the characteristics obtained using this method are more stable when changing the temperature of the liquid and its viscosity than the above. However, this method does not allow to obtain degressive characteristics with a sharply increased flow at high speeds.

 The problem solved by the proposed method is the ability to obtain any characteristics of the shock absorber.

 Known shock absorber - damper with a vortex fluid flow in the vortex chambers in the piston [2]. The design contains two vortex chambers. A vortex fluid flow and damping force are created in the first vortex chamber during the expansion stroke, and in the second during the compression stroke.

 The first bypass valve, which responds to the pressure difference between the supra-piston and sub-piston spaces, exceeds a predetermined value, directs the flow through the piston, bypassing the first vortex chamber, and the second bypass valve directs the fluid, bypassing the second vortex chamber when the specified pressure is exceeded during the piston return stroke.

 The disadvantage of this device is the inaccuracy of regulating the permissible differential pressure by spring bypass valves and the complexity of the design of the device.

 Known hydraulic shock absorber with a vortex valve, in which the listed disadvantages are reduced [3]. It consists of a cylindrical body, inside of which a piston is mounted on the rod. In the lower part of the piston, an outlet is made from the vortex chamber, in the side walls of which there are tangential inlet openings creating a vortex fluid flow.

 The disadvantage of the latter design is the difficulty of performing tangential channels and maintaining the required characteristics of the shock absorber.

 Known hydraulic shock absorber containing a housing filled with a working medium, a rod with a piston equipped with vortex chambers, which, due to a certain ratio of the geometric dimensions of the vortex chambers to the size of the piston, can improve its operational capabilities by expanding the range of variation of the damping coefficient [4].

 In its technical essence, the latest invention can serve as a prototype of the proposed solution.

 The problem solved by the invention is the ability to obtain any desired characteristics by grinding the costs of various flows, varying the shape and volume of the vortex chambers, improving the working conditions of the loaded nodes, chambers, simplifying the manufacturing technology of the device.

 The problem is solved in that the proposed device implements a new method of damping oscillations, which consists in absorbing energy by creating a vortex flow in a closed volume, the resistance of which is regulated by directing an additional corrective flow at an angle to the tangential one depending on the pressure difference between the high and low pressure regions and fluid viscosity in a specific proportion.

где Q_танг - расход тангенциального потока;
Q $\genfrac{}{}{0ex}{}{\text{лам}}{\text{кор}}$ - расход корректирующего потока.The ratio of costs in tangential and corrective flows is expressed by the ratio

where Q _tang is the flow rate of the tangential flow;
Q $\genfrac{}{}{0ex}{}{\text{llamas}}{\text{core}}$ - flow corrective flow.

 The specified method is implemented using the proposed design of the vortex hydraulic shock absorber, comprising a housing filled with liquid, a rod, a piston with a seal, equipped with at least one vortex chamber having a tangential channel with an inlet cavity, the vortex chamber being located asymmetrically on the peripheral part of the piston and is made in in the form of a closed volume, for example a cylindrical one, with an outlet in the bottom. Moreover, it is equipped with an additional correction channel, the axis of which is directed to the center of the outlet of the vortex chamber and, accordingly, perpendicular to the fluid flow formed by the tangential channel in the vortex chamber.

 In this case, the correction channel is made in the form of a hole in the wall of the vortex chamber. The outlet can be located eccentrically to the axis of the latter, and the tangential and corrective channels can be equipped with additional vortex chambers (pre-chambers). The execution of parallel holes of linear chokes is also allowed. The design involves making holes connecting the volume of the vortex chamber with a gap between the piston body and the seal. Vortex chambers working for compression and rebound can be made adjacent to a common outlet.

In FIG. 1 shows the design of the proposed vortex shock absorber, in FIG. 2 - its view B, FIG. 3 illustrates a diagram of fluid motion in channels and a swirl chamber; FIG. 4 shows additional pre-cameras. In FIG. 5 presents the characteristics of the proposed design obtained as a result of the experiment. Line 1 is the characteristic ΔP = f (Q) for a conventional linear inductor, curve 2 is the characteristic ΔP = f (Q ² ) of the vortex shock absorber. Curve 3 illustrates the operation of the proposed shock absorber, and curve 4 shows the effect of additional pre-chambers.

 The shock absorber consists of a cylindrical body 1, inside of which there is a rod 2 with a piston 3 mounted on it, equipped with vortex chambers 4 located asymmetrically along the peripheral part of the piston 3. They have a tangential channel 5 with an input cavity 6 and an additional correction channel 7, whose axis is directed to the center of the outlet 8, which can be eccentric to the volume of the chambers 4, the upper part of which is equipped with removable covers 9 with openings of the inlet cavity 6. The tangential 5 and corrective 7 channels each individually or both together can be equipped with additional pre-chambers 10 and 11, respectively (Fig. 4). The piston is equipped with seals 12. The chamber 4 is connected to the gap between the piston body 3 and the seal 12 with openings 13 (Fig. 2). In the piston 3 made linear chokes 14.

 In this case, the vortex chambers 4 can be located on the piston both from the side of the rod (rebound chamber) and from the opposite side (compression chamber) (Fig. 1). In this case, both vortex chambers are adjacent and connected by a common outlet 8.

Следует иметь в виду, что точность регулирования зависит от степени турбулентности реальных потоков. Поэтому максимальная точность будет тогда, когда корректирующий поток будет строго ламинарен, а тангенциальный турбулентен.The shock absorber implements the claimed method as follows. When the piston 3 moves, for example, upward above it, a high pressure region forms (Fig. 1). The fluid through the inlet cavity 6 and the tangential channel 5 rushes into the vortex chamber 4 along its walls, creating a tangential flow, which, twisting, forms a vortex that is removed into the outlet 8 in the bottom of the vortex chamber 4. In this case, the resistance to the piston movement has a quadratic dependence from the flow (curve 2, Fig. 5), and the energy spent on the formation of the vortex is dissipated in space and through the walls of the housing 1 is removed outside. The asymmetric peripheral location of the vortex chamber 4 and its connection with the gap between the piston body and the seal 12 contributes to better heat transfer. However, to correct the characteristic, it is sometimes necessary to change the flow of the flow formed by the tangential channel. In this case, its flow rate is regulated by directing an additional correction flow across the tangential flow through the correction channel 7 depending on the pressure difference between the high and low pressure regions and the viscosity of the working fluid (Fig. 3). In this case, the tangential flow with flow rate Q _tang has a quadratic or close to it resistance. Laminar corrective duct with flow rate Q $\genfrac{}{}{0ex}{}{\text{llamas}}{\text{core}}$ has linear resistance. This is ensured by the shape of the channels and the design of the vortex chamber. This is due to the difficulty of separation of the tangential flow from the walls of the vortex chamber 4 with insufficient flow of the corrective flow. However, as its productivity grows, its influence on the tangential flow increases and, at a certain ratio, the tangential flow breaks away from the walls and directs it directly into the outlet. This disruption of the vortex is accompanied by a sharp decrease in resistance to fluid motion (curve 3, Fig. 5) and is determined by the ratio

It should be borne in mind that the accuracy of regulation depends on the degree of turbulence of real flows. Therefore, the maximum accuracy will be when the corrective flow is strictly laminar and the tangential turbulent.

 By combining the geometric parameters of the prechambers 10 and 11, any desired characteristic can be achieved, for example, curve 4, FIG. 5. This is achieved by the fact that the vortex chambers have a quadratic dependence, which is more stable from viscosity than throttle channels with a straightforward dependence. Combining both characteristics, they obtain an overall stable characteristic in a wide range of shock absorber operating modes.

 Theoretical and practical studies have confirmed the reliability and feasibility of the proposed method and device for damping vehicle vibrations.

 The proposed method and device when testing prototype shock absorbers fully confirmed all the claimed benefits.

 The author has developed a method for calculating the proposed shock absorbers.

List of references
1. Nagorny V. S., Denisov A. A. The automation device of hydraulic and pneumatic systems. -M .: Higher school, 1991.

 2. US patent N 4515252, 1985. Damper with a swirl flow at the pistons.

 3. British patent N 2044882, 1980. Hydraulic damper with a swirl valve.

 4. Patent of Russia N 1746903, 1992. Hydraulic shock absorber (prototype).

Claims (10)

1. A method of damping oscillations, which consists in absorbing energy by creating a vortex fluid flow, followed by throttling the fluid flow through the holes and dissipating the heat energy released by the fluid flow, characterized in that the fluid flow is created in a closed volume by moving the fluid along a curved path through a tangential fluid supply to the specified curved path and adjust the hydraulic resistance, directing an additional laminar correcting fluid flow p At an angle to the tangential fluid flow, depending on the pressure difference between the high and low pressure regions and the viscosity of the working fluid, the flow ratio in the tangential and corrective flows is expressed by the ratio

Where
Q _tang - tangential flow rate;
Q $\genfrac{}{}{0ex}{}{\text{llamas}}{\text{core}}$ - flow corrective flow.  2. A vortex hydraulic shock absorber, comprising a housing filled with liquid, inside which a rod with a piston with a seal mounted on it, a vortex chamber and a tangential channel associated with it with an inlet cavity, characterized in that the vortex chamber is located asymmetrically on the peripheral part of the piston, is made in the form of a closed volume with an outlet in its bottom and equipped with an additional correction channel in communication with the input cavity of the tangential channel, and the axis of the correction the channel is directed towards the center of the specified outlet.  3. The shock absorber according to claim 2, characterized in that the vortex chamber includes an adjacent vortex compression chamber and a vortex rebound chamber communicated with each other by a common outlet.  4. The shock absorber according to claim 2, characterized in that the vortex chamber is made cylindrical with an axis parallel to the axis of the piston, the tangential channel is made in the piston tangentially to its cylindrical surface, and the correction channel is perpendicular to it.  5. The shock absorber according to claim 2, characterized in that the correction channel is made in the form of holes in the upper part of the vortex chamber.  6. The shock absorber according to claim 2, characterized in that the outlet of the vortex chamber is eccentric to the axis of the latter.  7. The shock absorber according to claim 2, characterized in that the correction channel is equipped with a vortex chamber.  8. The shock absorber according to claim 2, characterized in that the tangential channel is provided with a vortex chamber.  9. The shock absorber according to claim 2, characterized in that the capillary holes of the linear chokes are made in the piston body parallel to the axis of the vortex chamber.  10. The shock absorber according to claim 2, characterized in that the gap between the piston seal and the piston body is in communication with the vortex chamber through openings.

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