Messerschmitt-boelkow-blohm Gesellschaft MIT Beschraenkter Haftung

Messerschmitt-bolkow-blohm Gesellschaft MIT Beschrankter Haftung

Dieter Braun

Wolfgang Buchs

Andreas Kirchner

A vibration isolator is formed with a spring mechanism and a fluid transmion mechanism interposed between a vibrating member and a support member. The fluid transmission mechanism includes a primary fluid chamber and a secondary fluid chamber, with the secondary fluid chamber being deformed to a greater extent than the primary fluid chamber as a result of vibrations. An inertia mass operatively associated with the secondary fluid chamber is displaced as a result of vibrations and is thereby accelerated with a resulting inertia force causing fluid pressure change in the fluid transmission mechanism which compensates as a dynamic force the dynamic portion of the spring force transmitted from the spring mechanism to the support member.

Vibration isolator particularly of the antiresonance force type

A vibration isolator (1) with two degrees of freedom works according to the nti-resonance principle. The vibration isolator is arranged, for example, between a first body, such as a helicopter frame 13, and a second vibration generating body such as a rotor-transmission unit 12 vibrating at a predominant frequency. A spring arrangement (2) is connected to the attachment points (14, 15) for the first and second bodies. The spring arrangement works in conjunction with a pendulum rod (3) which is attached to the two bodies (12, 13) by spherical pivot bearings (5, 10). The vibration isolator has a compact construction and a low characteristic damping since the spring arrangement includes several relatively small semi-circular or spiral-shaped wound leaf springs (7-1 to 7-4) which extend between an inner ring (4) and an outer ring (6). The pendulum rod is held in a spherical pivot bearing (5) in the inner ring, and a further spherical pivot bearing (10) is connected by a flange (9) to the outer ring. A pendulum weight (11) is slidably mounted on the free end of the pendulum rod. The other end of the pendulum rod is held by the two pivot bearings.

Vibration isolator

The neck of a hingeless helicopter rotor wing blade is provided with a damping device effective to dampen lead-lag movements of the rotor wing blade. For this purpose the damping device comprises at least two stiff plates secured to opposite sides of the blade neck by a plurality of elastomeric members glued or bonded to the respective stiff plate and to the blade neck at spaced intervals. The difference of deformation between the stiff plates and the blade neck causes a deformation of the individual members in directions substantially across the longitudinal blade direction (in lead-lag plane). The spacings between adjacent members are located where the damping action is inherently low.

Growing community of inventors

Oberpframmern, Germany

Dieter Braun