Showing papers on "Damper published in 1989"

Permanent magnet linear motors used as variable mechanical dampers for vehicle suspensions

Abstract: SUMMARY Linear electrodynamic motors consisting of coils of copper wire interacting with magnetic fields produced by permanent magnets can be used to construct mechanical dampers with a damping coefficient which can be rapidly varied by changing the external resistance connected to the coil. Limitations to the use of these variable dampers arise due to the coil's own resistance and mass and the practically achievable magnetic field. A moving coil system is first analyzed and then modifications to the basic results when a moving magnet design is used are given. The results indicate that for the oscillation freauencies tvoicallv encountered in road vehicle suspensions, electrodynamic variable shock absorbers are feasible. A novel coreless design appropriate for use with high energy permanent magnets is proposed which would significantly reduce the weight of the units.

Seismic response of steel frame structures with added viscoelastic dampers

Abstract: The feasibility of using viscoelastic (VE) dampers to mitigate earthquake-induced structural response is studied in this paper. The properties of VE dampers are briefly described. A procedure for evaluating the VE damping effect when added to a structure is proposed in which the damping effect of VE dampers is incorporated into modal damping ratios through an energy approach. Computer simulation of the damped response of a multi-storey steel frame structure shows significant reduction in floor displacement levels.

Apparatus for damping courses of motion

Abstract: An apparatus for damping movement courses of two bodies, in particular in a vehicle wheel/vehicle suspension system, having a piston sliding in a cylinder and dividing it into two work chambers, the two work chambers arranged to communicate with one another via respective oppositely acting check valves and via a variably asymmetrical damper valve adjustable in such a manner that upon a valve member movement the opening cross section for one flow direction decreases to the extent that it increases for the other flow direction, such that whenever in comparison with an active damper system energy would have to be supplied from outside, the damper force is substantially reduced to the value of zero.

Elasto-plastic damper

Abstract: An elasto-plastic damper is adapted to be used in a structure, such as a building and other facilities, for absorbing vibration energy created by earthquake tremors and other ground vibrations. The damper is a centrally bulged and generally cone-shaped hollow body of revolution so that its section modulus changes substantially porportional to a bending moment created in the damper body due to horizontal stresses, thus permitting a maximum degree of deformability. This elasto-plastic damper is compact in size and demonstrates a high degree of vibrational energy absorbability.

Battery module for the engine compartment of an automobile

Abstract: A battery module for insulating a battery from the heat of the engine of a motor vehicle, the module including a battery compartment, an air inlet and an air outlet, a first air flow path connecting the air inlet to the air outlet and a second air flow path around the outside of the battery compartment connecting the air inlet to the air outlet, a damper positioned in the housing for movement between a first position wherein the first air flow path is open and the second air flow path is closed and a second position wherein the first air flow path is closed and the second air flow path is open, a shape memory alloy member for moving the damper from the first position to the second position when the ambient temperature exceeds a predetermined minimum and a spring for biasing the damper to the first position when the ambient temperature is less than the predetermined temperature.

Cavitation Leading to a Two Phase Fluid in a Squeeze Film Damper

Abstract: Performance prediction of squeeze film bearing dampers depends largely on the extent and type of cavitation taking place within the squeeze film land. The investigation described here was intended to probe the phenomenon of cavitation in squeeze film dampers and provide some insight, answers, and possible explanations for some of the measurements and behavior which are generally not predicted by classical lubrication theory. High speed photography was utilized to verify the occurance of vapor cavitation, as well as that of gaseous cavitation which later developed into a two phase homogeneous mixture of oil and air when the test rig was operated at higher speeds. Video recordings at slower speeds showed a blurred image of the trace the bubbles moved through and thus provided a visual record of the flow reversal and oscillatory motion in the squeeze film damper. Presented at the 43rd Annual Meeting in Cleveland, Ohio May 9–12, 1988

Zone control system providing synchronization of system operation with the zone of greatest demand

Abstract: A zone control system uses signals from a plurality of separate zone thermostats to determine the zone of greatest thermal load or demand. Specifically, the on-time of each thermostat signal is integrated with respect to time so that the zone of greatest demand can be determined. The thermostat signal from the zone of greatest demand is used to control a duct damper between that zone and a heating/cooling plant. To synchronize the opening of the other zone duct dampers with the duct damper of the zone of greatest demand, the length of each of the on-periods of the thermostats in the other zones is first converted to the cycle rate of the zone of greatest demand thermostat since the other thermostats are operating at different duty cycles. A microprocessor-based master zone controller uses these converted on-signals to control respective zone duct dampers in the other zones coincident with the start of the thermostat on-period of the zone of greatest demand. Thus, the duty cycle of these duct control signals is equal to the duty cycles of the thermostats in the corresponding zones, but the control signals have time periods equal to that of the control signal for the zone of greatest demand.

Method of operating a vibration attenuating system having semi-active damper means

Abstract: The system includes at least one semiactive damper whose switching between high damping and low damping states is at times delayed until the relative velocity across the damper is no greater than a preselected low magnitude, or until the energy stored by a resilient deformable system member is no greater than a predetermined magnitude, or until the first to occur of either of the foregoing events.

Adjustable vibration dampers for motor vehicles

Abstract: An adjustable vibration damper is for a motor vehicle or the like. The vibration damper includes a cylinder containing a damping medium. A piston is disposed within the cylinder for movement of the damping medium. A valve device is connected to the cylinder for flow of the damping medium therethrough. The valve device has at least a first damping element and a second damping element. The first damping element includes a first compression valve assembly and a first decompression valve assembly. The second damping element includes a second compression valve assembly and a second decompression valve assembly. The first compression valve assembly, the first decompression valve assembly, the second compression valve assembly, and the second decompression valve assembly have respective damping characteristics. There is included switching apparatus for selectively switching to at least one of the first and the second damping elements to select the respective damping characteristics thereof.

Personal environmental module.

Abstract: A personal environmental module (10) for controlling the environment in a work space, the module (10) including a housing (30) having an air inlet and a pair of air outlets (26), a pair of dampers (40, 42) mounted in the air inlet, one of the dampers (40) being connected to a preconditioned air source, the other damper (42) being connected to room air, a pair of fans (45, 46) mounted in the housing (30) in a position to allow air through the dampers (40, 42), a controller (60) for controlling the speed of the fans (45, 46) and the amount of air flowing through the dampers and a control panel (28) operatively connected to the controller for setting the speed of the fans and the temperature of the air discharged through the outlets (26). A baffle (51) is provided in the housing (30) to direct a portion of the air from each fan (45, 46) into the air flowing from the other fan in order to mix the preconditioned air with the room air. An electrostatic filter (48) and white noise generator (100) can be mounted in the housing (30) and a light sensor (64) and occupant sensor (62) operatively connected to the controller.

Semi-active damper valve means with electromagnetically movable discs in the piston

Abstract: An improved method and means for control and accomplishment of semi-active damper means transition between high damping and low damping states is provided which takes advantage of the available inherent dynamic fluid pressure forces produced by the condition of motion between supported and supporting members. Deferral or delay of damper state transitions to avoid force discontinuities or system noise is accomplished mechanically, or automatically internal to the structure of the adjustable valve means. The delay of damper state transition from high to low and low to high damping is accomplished independent of the particular control policy utilized until the fluid pressure differential across the valve ring members is a preselected low value. Commanded valve switching and motion condition sensing requirements are also minimized by reversible check valve means. Damper state transitions normally required based on a sign change in relative velocity are accomplished without actuated change in valve ring position by one of the inner and outer valve rings (in the "off" state) which floats between flow permitting and flow restricting positions dependent upon the direction of fluid flow through the piston.

Torsional damper type flywheel device

Abstract: A torsional damper type flywheel device includes drive side and driven side flywheels, a first spring mechanism connecting the drive side and driven side flywheels, a second spring mechanism which may include an air cushion spring, and a viscous damping mechanism arranged in series with the second spring mechanism. The series combination of the second spring mechanism and the viscous damping mechanism is arranged parallel to the first spring mechanism and connects the drive side and driven side flywheels. This flywheel device continuously changes its vibrational bahavior between two characteristics due to the action of the viscous damping mechanism. Due to the vibrational behavior change, no notable resonance occurs when the rotational speed passes through the resonance speed of the flywheel device. A continuously sliding friction mechanism is not used.

Air flotation dryer with built-in afterburner

Abstract: An internal exhaust fan (56) propels internal solvent-laden air across a burner (66) where it combusts, causing a heat rise. Heated, combusted air is routed to a recirculating supply air fan (50) which provides for pressurized heated air for air bars (28a-28n, 30a-30n) for drying a web. Heated air in excess of that required to dry the web is vented externally and helps to maintain desired solvent concentration levels. Variable parameters such as fan speed, burner temperatures, air box pressures, exhaust air rate, solvent concentration, supply air flow, supply air temperature and damper vane position are monitored, and the components are actuated to effect a high level of clean up efficiency.

Vibration-isolating machine mount.

Abstract: A vibration isolator is operatively associated with a suspension having a spring (21) and a fluid damper (22) arranged in parallel with one another between two masses (23, 24) which are arranged to move relatively toward and away from one another. A restricted orifice (33) communicates the opposed damper chambers (30, 31). The vibration isolator includes a fluid pump (46) and an actuator (48) for operating the pump. The pump has a first chamber (51) communicating with the damper first chamber (30), and has a second chamber (52) communicating with the damper second chamber (31). The pump is selectively operated so as to create a pressure differential across the orifice to oppose and substantially cancel the dynamic force transmitted through the spring and damper and attributable to high-frequency relative vibration between the masses, while permitting the damper to damp low-frequency relative velocity between the masses.

Method for regulation of ventilation as well as an air-conditioning device used in the method

Abstract: The invention concerns a method for regulation of ventilation, wherein air is removed out of a room space (H) or equivalent through an air-conditioning device (10) as outlet air (L1) and in which said air-conditioning device (10) part of the outlet air is recirculated as return air (L2) back into the room space, whereby return air (L2) is mixed with outdoor air to be passed into the room space. Before the outlet air (L1) is made to flow via the return-air damper (15) to the point of mixing (C) of return air (L2) and outdoor air, the outlet air is fitted to flow first via the outlet-air damper (14) placed in the outlet-air duct (11a) and, thereupon, via the return-air damper (15). The portion (L3) of the outlet air (L1) that is not recirculated via the return-air damper (15) or equivalent is removed as waste air (L3), without throttling, out of the air-conditioning device. The invention also concerns an air-conditioning device.

Multi-film fluid bearing damper

Abstract: A fluid bearing damper for damping radial motion of a bearing includes a plurality of concentric, circular, thin shims located in an annular damping chamber to present thin, radially stacked damping cavities. A portion of the shims have protruding radial lands that partially define the cavities, carry radial loads through the damper and produce a controlled mechanical centering force as well as serving to ensure replenishment of fluid film cavities.

Variable air volume ventilation system and method

Abstract: Generally there is provided for placement in the supply and return air ducts of a building ventilation system, a unique flow control unit having an orifice, static pressure sensors on opposite sides of the orifice, and sensor controlled dampers to regulate flow through the unit. In a further aspect, a remote static pressure sensor may be located at a strategic position in the ducts and arranged to control the dampers in the flow control units to alter the flow through the unit in response to system demand. In another aspect there is described a terminal box of similar design for controlling flow into and out of a room. This box provides center dampers on both supply and return ducts and pressure sensors on both sides of the center dampers. Under control of the room thermostat, both center dampers are adjusted under common control. The pressure sensors on either side of the center dampers are connected to control end dampers upstream and downstream of the unit in reponse to a chosen pressure differential.

Support for oil film dampers

Abstract: A relatively less complex segmented spring mounted under the bearing and damper or the same configuration segmented spring mounted on either side of the bearing and damper serves to center the shaft of a rotor of a gas turbine engine and is characterized as being simple, occupying minimum space, but being capable of maintaining an adequate fatigue stress margin.

Semi-active damper valve means and method

Abstract: An improved method and means for control and accomplishment of semi-damper assembly transition between high damping and low damping states is provided which takes advantage of the available inherent dynamic fluid pressure forces produced by the condition of motion between supported and supporting members. Deferral or delay of damper state transitions to avoid force discontinuities or system noise is accomplished mechanically, or automatically internal to the structure of the adjustable valve assembly. A voice coil actuated valve slider is operable within the piston of the damper assembly to modulate the damping coefficient in conjunction with check valves. The delay of damper state transition from high to low damping is accomplished independent of the particular control policy utilized until the fluid pressure differential across the valve slide is a preselected low value. Commanded valve switching and motion condition sensing requirements are also minimized by the reversible check valves. Damper state transitions normally required based on a sign change in relative velocity are accomplished without commanded slider movement by the check which are fluid pressure actuated according to the direction of fluid flow through the damper.

Vibration damping apparatus for transportation

Abstract: A vibration damping apparatus for transportation includes a vertical direction damping device having air springs and air dampers arranged in parallel on a base and horizontal direction damping device having laminated rubbers. The vertical and horizontal damping devices are combined in series for supporting a load base. The apparatus further includes an air supply source for supplying air into the air springs, control valves provided between the air springs and the air supply source for controlling air supply into and exhaust from the air springs, displacement detecting device for detecting displacements of the load base relative to the bases, and control device for controlling the control valves on the basis of results detected by the displacement detecting device to maintain the load base horizontally and at a constant level relative to the base whatever load is loaded on the load base.

Damper assembly for a strut in a jet propulsion engine

Abstract: The present invention is a damper assembly included in a strut on the front frame for a jet propulsion engine. The damper assembly is disposed within the strut for damping vibration of the strut as a result of air stream pressure pulses from first stage fan blades causing strut excitation when the fan blades are operating at least at transonic speeds.

Electrical connector system

Abstract: A suspension damper system is provided. The damper system includes a damper with a damper rod, a portion of which extends from the proximal end of the damper. The damper rod includes a bore and an electrode disposed within the bore. A fastener for securing the damper rod to a vehicle is also provided. The fastener is disposed over the damper rod and includes a circumferential groove. An electrical connector which includes an electrically conducting terminal is connected to the electrode. The connector includes a lock which mates with the groove in the fastener and includes a ground terminal which is connected to the damper rod.

Active Parameter Control of Nonlinear Vibrating Structures

Abstract: The procedure uses nonlinear auxiliary mass dampers with adjustable motion-limiting stops located at selected positions throughout a given nonlinear system. The degree of the primary structure oscillation near each vibration damper determines the damper's actively-controlled gap size and activation time. By using control energy to adjust the damper parameters instead of directly attenuating the motion of the primary system, a significant improvements is achieved in the total amount of energy expended to accomplish a given level of vibration control. In a related paper, the direct method of Lyapunov is used to establish that the response of the controlled nonlinear primary structure is Lagrange stable

Continuously variable transmission system and long travel torsion damper therefor

Abstract: This invention relates to a unique transmission system for applying torque from an engine flywheel to the drive train of an automotive vehicle including a long travel viscous damped torsional damper driven by the flywheel and coupled to a continuously variable transmission which in turn is coupled to a wet drive clutch, the output of which is connected to an output counter shaft for the automotive drive train. An important part of the unique combination is the long travel viscous damped torsional damper of the invention which includes an enclosed, effectively sealed housing contains input and output members coupled through a plurality of series parallel spring sets and immersed in a viscous medium to provide effective viscous damping matched to the effective spring rate of the mechanical damping system to accommodate both transient and steady-state vibrational torques. The damper is especially useful with the continuously variable transmission but is useful in other applications as well.

Clutch disk with torsional damper device

Abstract: A clutch plate for use in friction clutches has an output component in the form of a hub which is connectable to the input shaft of a variable-speed transmission, and an input component in the form of two spaced-apart disc-shaped walls which receive torque from a flywheel when the clutch is engaged. Two dampers are installed between the input and output components, and two diaphragm springs are provided to maintain the members of one damper and the elements of the other damper in proper axial positions relative to each other and relative to the components of the clutch plate. Plastic inserts are used to reduce wear upon metallic parts. One of the dampers is operative alone during a first stage of angular movement of the input and output components relative to each other, and the other damper is operative alone during the next-following stage of such angular movement. Relatively weak energy storing springs operate between the input and output members of the one damper, and stronger or stiffer energy storing springs operate between the input and output elements of the other damper.

Apparatus for regulating air flow through an air port of a chemical recovery furnace

Abstract: Apparatus for regulating air flow through an air port in a chemical recovery furnace. A plenum having an adjustable damper mounted inside a wind box associated with the furnace adjacent to the air port supplies and regulates the flow of air from the wind box to the furnace through the air port. A metal cleaning head adapted for rotatable insertion into the air port for cleaning excrescent material from the peripheral edges of the air port without blocking air flow through the port is pivotally mounted in a retracted, at-rest position adjacent to and above the air port so as not to interfere with movement of the adjustable damper. During a cleaning cycle, the damper is moved to a retracted position on the floor of the plenum so as not to interfere with the moving cleaning head. A short stroke, double articulated damper positioning mechanism facilitates movement of the damper blade in limited space.