摘要:
A method is described for identifying the primary load path of a particular engine. An elastomeric mount may then be made laterally soft in a first (in the disclosed case, the tangential) direction and more rigid in the direction of the primary load path. Efforts can then be directed to dynamically softening the mount in the primary load path. Specific apparatus may include passive fluid devices, active fluid devices, passive non-fluid devices and active non-fluid devices. In the case of a fluid mount, another feature of the invention is to have an auxiliary fill port of the volume compensator in alignment with at least one and, preferably both, of the primary fill port for the mount and the inertia track to facilitate filling.
摘要:
A damping device which provides superior damping stiffness K", has linear damping characteristics as a function of amplitude and for which the temperature sensitivities of stiffnesses K*, K", K' have been minimized. The device includes a first second fluid-filled chambers which are interconnected by a passageway. The length and diameter of the passageway, as well as the fluid viscosity, are chosen to give the optimum damping characteristics. Further, a plurality of spring loaded pressure relief valves are integrated into the assembly to allow more flow area to open when a threshold pressure is encountered, thereby reducing the internal pressures and dynamic stiffness K* at cold temperatures.
摘要:
A fluid and elastomer device for isolating dynamic loading between members connected to the device, the fluid and elastomer device comprising: an inner member that defines a compliance chamber; an outer member that defines an outer housing chamber; an elastomeric element flexibly interconnecting said inner member relative to said outer member; a passageway located in the compliance chamber and flow connecting the compliance chamber with a primary working chamber; a secondary compliance member joined to the passageway in the compliance chamber; a volume compensator located in the housing chamber the volume compensator comprising spring means, piston member at one spring end and a diaphragm member that overlies the piston; a member located between the compliance and housing chambers, the member being moveable with the outer housing, the moveable member in combination with the diaphragm defining a compensator chamber; and a volume of working fluid in said chambers and passageway.
摘要:
A torque-restraint mounting system for connecting an aircraft engine to a structure including at least two hydraulic mountings and at least one other resilient mounting. At least two of the hydraulic mountings are fluidicly interconnected via a fluid filled conduit. This allows for the torque to be reacted between the aircraft engine and the structure by placing the fluid in compression. The relative torque-induced displacement occurring between the aircraft engine and the structure for any specific operating copndition is counteracted by tuning the amount or volume of fluid within the torque-restraint system, or by tuning the coefficient of thermal expansion of the fluid. Thus, as the torque-restraint mounting system heats up, the aircraft engine will change rotational position such that its room temperature untorqued orientation can be maintained. This can have significant benefits in terms of increasing service life of the engine mounting system.
摘要:
A reversible endless belt rotary coupling particularly suited for use in connecting a drive shaft and driven shaft permitting the driven shaft to rotate in either, rotational direction and to rotate about an axis that may be angularly misaligned with respect to the rotational axis of the drive shaft. The coupling includes a series of preloaded endless belts embedded in an elastomer matrix material, arranged tangentially with respect to the connected shafts and connected thereto by bobbin-like spools at the ends of the belts. The endless belts are axially stiff to accommodate tensile and compression loads and are flexibly and torsionally soft to accommodate the motion while transferring torque between the drive and driven shaft.
摘要:
A rotor blade retention system connects an elongated rotor blade to a rotor hub that is rotatable about its central axis. The connected rotor blade normally extends generally radially from the hub and is rotatable with the hub. The retention system includes a pair of bearings that are interconnected in parallel load transmitting relationship. Both bearings are connected in serial load transmitting relationship with a flap hinge. One bearing is relatively stiff along the longitudinal axis of the rotor blade and is less stiff in directions transverse to the longitudinal blade axis. The other bearing is most stiff in directions transverse to the rotor blade axis and is less stiff along the axis. Both bearings define effective elastic centers which are located along the longitudinal blade axis, but the two elastic centers are spaced from each other. The two bearings accommodate lead-lag motions of the rotor blade. Because of the relative stiffnesses of the bearings in directions transverse to the longitudinal axis of the rotor blade, the axis about which lead-lag motion occurs is displaced from the effective elastic center of the bearing that has its greatest stiffness along the longitudinal blade axis. The displacement of the lead-lag axis causes the bearing, and the retention system, to appear relatively stiff in response to lead-lag motions. The stiffness of the blade retention system in response to flapping motions of the rotor blade is not affected, however, because the serially connected flap hinge accommodates most of the flapping motion in preference to the bearings. Since the retention system is relatively stiff in response to lead-lag motions, less damping is required at the natural frequencies of lead-lag motion. The required damping may be provided entirely by material incorporated into the bearings and without the use of an auxiliary lead-lag damper.
摘要:
A fluid isolator apparatus (20) for isolating vibration between a vibrating member, such as a helicopter transmission or pylon and another structure, such as a helicopter fuselage. In one aspect, the fluid and elastomer apparatus (20) includes an inner member (24), an outer member (22), and an elastomer element (26) flexibly interconnecting them. First (30) and second (34) operating chambers are interconnected by a passageway (36). Fluid (37) oscillates between the operating chambers (32, 34) through passageway (36). A spring (42) flexibly suspends the piston (40) such that dynamic motion between said inner and outer member (24, 22) displaces piston (40) and spring (42). Preferably the a hollow cavity (28) houses both the piston (40) and a metal coil spring (42). The stiffness of the coil spring (42) may be interchanged to adjust a resonant parameter. Optionally, the piston mass itself or an additional tuning mass (58) mounted on the piston (40) may be used to accomplish tuning. Embodiments describing pistons (40) including rolling diaphragms, elastomer tubeforms, and metal bellows are described.
摘要:
A fluid damper to damp unwanted vibration between a first member (21) and a second member (23, 23'), such as between a rotor blade and hub within a helicopter rotor system. According to a first aspect, the fluid damper (20) includes an outer member (22), first and second inner members (24, 24'), first and second elastomeric elements (26, 26'), a hollow (28), a divider (30) subdividing hollow (28) into first (32) and second (32') operating chambers, a connector (34) interconnecting first (24) and second (24') inner members, a fluid passageway (36) interconnecting operating chambers (32, 32'), a fluid (38) contained within said passageway (36) and operating chambers (32, 32'), and a volume compensator (40) including a compensator chamber (42) housed within one of first (24) and second (24') inner members. In another aspect, an annular bubble trap (58) is formed in a wall portion (62) of the operating chamber (32) to focus any air bubbles into a fill port (54) during fill. In another aspect, a first chamber fill port (54) and a second chamber fill port (54') each interconnect with the annular bubble trap (58) to aid in filling the chamber (32') and removing air bubbles therefrom. In yet another aspect, a first fill port (54) interconnects to the operating chambers (32, 32') and a second fill port (56) interconnects to the compensator chamber (42) for allowing separate fill of the compensator (42) and operating chambers (32, 32').
摘要:
A lightweight, flexible coupling suitable for transmitting torque and accommodating axial and angular misalignment between drive and driven members. The coupling includes at least one reinforcing rim disposed between a pair of hubs having a plurality of projecting pins about which are secured filaments that are coated with a flexible matrix material. The filaments are geodesically wrapped from the hub one side of the reinforcing ring and then to the hub on the opposite side of the reinforcing ring. The driven and driven members are respectively attached to the projecting pins.
摘要:
A mount capable of being pressed into an installed position in a hole in a plate. The mount has inner and outer concentric annular elements connected together by an intermediate flexible thermoplastic elastomeric web. The outer annular element has a peripheral groove which receives the plate and a deflectable wall with a chamfered outer surface and a series of slots. The flexible web permits the inner element to vibrate with respect to the plate and thereby isolate an item from the plate.