A hydropneumatic shock absorber

IPC classes for russian patent A hydropneumatic shock absorber (RU 2043946):

B64C25/58 - Arrangements or adaptations of shock-absorbers or springs (shimmy-dampers B64C0025500000; vehicle suspension arrangements in general B60G; shock-absorbers per seF16F)

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(57) Abstract:

The invention relates to aeronautical engineering, chassis shock absorber aircraft. A hydropneumatic shock absorber includes a housing placed in it a rod with a piston. In stock under its piston has a floating piston with a cylindrical rod having a profiled groove. The shock absorber also has pneumatic and hydraulic chamber, and the ratio of the area of the cylindrical rod to the area of the floating piston is from 0.25 to 0.5. This implementation will allow to increase the efficiency of reducing the dynamic loads transmitted to the aircraft during its movement on uneven runway with heavy loads. 3 Il.

The invention relates to an aircraft, in particular to the chassis shock absorber aircraft.

Known hydropneumatic shock absorber, comprising a housing placed in it a hollow rod with a piston, pneumatic and hydraulic chamber.

The drawback of such absorbers is pretty high weight and high dynamic loads transmitted to the aircraft during its movement on the runway.

The invention a movement on uneven runway, and weight loss designs.

The problem is solved in that in the single-chamber hydro-pneumatic shock absorber, comprising a housing placed in it a hollow rod with a piston, pneumatic and hydraulic chamber, is installed in the hollow rod floating piston with a fixed coaxial cylindrical rod passing through the piston rod. For sealing the cylindrical surface of the rod has longitudinal grooves (channels) of variable cross-section for flowing fluid, and the ratio of the area of the cylindrical rod to the area of the floating piston is from 0.25 to 0.5.

In Fig.1 shows the proposed absorber of Fig.2 and 3 are diagrams efforts compression.

A pneumatic shock absorber consists of a body 1, a piston 2 piston 3, the floating piston 4 with a cylindrical rod 5, the hydraulic G and D cameras, pneumatic P chamber, the hydraulic chamber T brake rod 2 during the reverse course with the spring loaded valve 6, valve 7 and the tube 8. On the cylindrical rod 5 is made of profiled grooves 9.

Direct stroke 2 (compression) shock absorber displaced by the piston 3, the fluid from the chamber D flows through the openings f is of the rod 2. While moving the floating piston 4 compresses the gas in the pneumatic chamber P.

Depending on the speed compression damper has three modes of operation.

The first compression mode at low speeds, which corresponds to the movement of the aircraft in taxiing.

At low speed compression damper brake fluid at the end of the chamber G is virtually absent. The fluid displaced by the piston 3, enters the chamber D and moves the floating piston 4, which compresses the gas in the chamber P. This mode is illustrated in the graph of dependence of the compression force of the shock absorber Q from stroke S (Fig.2), where Q₁the force of the shock absorber during compression at low speed; Q₀the initial elastic force.

The second mode corresponds to a dynamic compression of the shock absorber that takes place during landing of the aircraft.

In this mode, the dissipation of the impact energy involved working fluid. Displaced from the chamber G is a fluid's resistance to flow under pressure in the chamber G through the holes and grooves 9 variable cross-section f_varin the chamber D, the floating piston 4 will move with great speed, which leads to compression of gasmi Q₂and Q₃where Q₂the curve of the elastic force on the shock absorber during polytropic compression of the gas in the chamber P, equal division of the gas multiplied by the square rod; Q₃external characteristics of the efforts absorber equal to the fluid pressure in the chamber G, multiplied by the area of the stem.

In this mode, the higher the speed of compression of the shock absorber, the greater hydraulic resistance flowing from the chamber G of the liquid. In this case, since on the face area of a cylindrical rod operates a full fluid pressure and force from this pressure is directly transmitted to the floating piston, then with increasing speed of the spindle and a corresponding increase in the speed of movement of the floating piston, the fluid pressure in the chamber D due to resistance in the ducts f and f_vardecreases and at some value of the speed of the floating piston becomes equal to zero (more precisely, the vapor pressure of the liquid), which means disconnected similarity nature of the flow in the ducts f and f_var.

With further increase of the speed of movement of the RAM will be the limiting fluid pressure in the chamber, the amount of the limit of fluid pressure determined by the gas pressure in the chamber P, multiplied by unitedthe impact of the aircraft on the runway roughness at high speed during takeoff or posleprodazhnogo mileage. The speed of compression of the shock absorber exceeds the speed when landing the blow.

In the third mode, the floating piston 4 with a cylindrical rod plays the role of the safety device. The operation of the shock absorber is as follows. When hitting an aircraft on the unevenness of the speed of movement of the RAM 3 is sharply increased hydraulic resistance flowing from the chamber G through the ducts f and f_varfluid pressure in the chamber G, and the camera D decreases and approaches zero.

The fluid pressure in the chamber G is limited by the magnitude of the gas pressure in the chamber P, multiplied by the ratio of the area of the floating piston to the area of a cylindrical rod. Thus, the damper moves to the mode of operation is similar to operation of the air spring pressure.

In this mode, the resistance force of the shock absorber does not depend on the speed of contraction and restrictive level of effort is determined by the design parameter is the ratio of total area of the floating piston and connected to a cylindrical rod.

After the end of the forward stroke, regardless of the mode, there is a return stroke under the action of compressed gas in CA is aetsa due to the resistance of the liquid, resulting from the reverse camera braking T through an orifice in the closed valve 6, the direction of fluid flow indicated by the arrows OH Fig.1.

The shock absorber fully satisfies a variety of loading conditions, i.e., has mnogoseriinomu that provides effective reduction of ground loads transmitted to the aircraft when landing punches and movement on rough runways, and has constructive simplicity, low weight and high reliability.

A HYDROPNEUMATIC shock ABSORBER, comprising a housing placed in it a hollow rod with a piston, pneumatic and hydraulic chamber, characterized in that the hollow shaft is placed a floating piston with a fixed coaxial cylindrical rod passing through the piston rod and sealing the cylindrical surface of which is made of the longitudinal grooves of variable cross-section for flowing fluid, and the ratio of the area of the cylindrical rod to the area of the floating piston is 0.25 to 0.5.