Showing papers on "Damper published in 1988"

Parametric studies on tuned liquid damper (TLD) using circular containers by free-oscillation experiments.

Abstract: A new kind of damper, Tuned Liquid Damper (TLD) relying on motion of shallow liquid in a rigid cylinder, is experimentally studied. Prototype-sized circular containers with diameters 40cm and 60cm and partially filled with water, are attached to a single-degree-of-freedom structural model with natural period of 2sec. The damper effect is measured in terms of the increase in the logarithmic rate of decrement of free oscillation of the main structure. The structural displacements range from 8cm down to 0.25cm. It is seen that, for large damping effect at small amplitude of structural vibration, it is necessary to tune the fundamental sloshing period of the liquid to the natural period of structure; hence the name Tuned Liquid Damper. Breaking of surface waves, which is dependent on structural vibration amplitude, appears to be a major mechanism of energy dissipation in the range of displacements considered. Also investigated are the effects of: ratio of liquid frequency to structure frequency; liquid viscosity; container bottom roughness; container roof height; ratio of liquid mass to structure mass; and container diameter.

Air spring damper for vehicle suspension

Abstract: An air spring damper used in a vehicle suspension system with upper, intermediate and lower chambers and incorporating a reservoir tube which has an anti-friction rod guide and bearing assembly therein which lubricates the hollow rod of a piston as it strokes in their reservoir tube in jounce and rebound An elastomeric air sleeve is featured which is connected to a top mount fastened to the vehicle body An elastomeric isolator of this mount pivotally connects the piston rod to the body while sealing the upper end of the air sleeve The air sleeve is supported full time by an outer elastomeric sleeve for improved air sleeve operation A jounce bumper mounted internal of the reservoir tube is compressible to resist and cushion jounce strokes of the piston This damper provides optimized vehicle body isolation and damping of both body and wheel axle at their natural frequencies

Torque transmitting and torsion damping apparatus for use in motor vehicles

Abstract: A torsion damping apparatus between the crankshaft of the engine and the input shaft of the change-speed transmission of a motor vehicle has two flywheels one of which is driven by the crankshaft and the other of which drives the input shaft by way of a friction clutch which generates heat. In order to prevent the transfer of heat from the friction clutch to the antifriction bearing between the flywheels, which are rotatable relative to each other against the opposition of a damper, the bearing is at least partially surrounded by a thermal barrier of synthetic plastic, ceramic or metallic material which prolongs the useful life of the bearing and enhances the torsion damping action of the damper. The thermal barrier can constitute or form part of the damper. The bearing can be disposed radially inwardly of the location of engagement between the clutch and the other flywheel and can be cooled by streams of air flowing through an annulus of passages each having a first end disposed radially inwardly of the friction surface of the other flywheel and a larger second end in a second surface of the other flywheel opposite the friction surface. Heat barriers in the other flywheel can alternate with the passages in the circumferential direction of the other flywheel.

Temperature control system for air conditioning system

Abstract: A temperature control system for an air conditioning system that services plural zones provides priority of one or more selected zones of the conditioned air flow relative to the other unselected zones. Priority is achieved by closing those dampers associated with the unselected zones to direct the conditioned air flow into the selected zones. The temperature control system also provides for fail-safe operation by utilizing dampers biased in the open position and by preventing all dampers from being closed at the same time when conditioned air is flowing.

Mechanical Damper Using Piezoelectric Ceramics

Abstract: A piezoelectric ceramic mechanical damper with a controllable damping factor has been developed. Mechanical vibration energy is transformed through the piezoelectric effect into electrical energy which is dissipated through an external resistance. A significant variation in damping factor is realized when the external resistance is changed.

Computation of winding inductances of permanent magnet brushless DC motors with damper windings by energy perturbation

Abstract: A method for the calculation of motor winding inductances is presented in which damping effects due to metallic retainment sleeves and intentionally introduced damper bar (amortisseur) windings are included. The inductance computation method makes use of the combined energy perturbation concept and finite-element field solutions. These parameters are necessary for the prediction of the dynamic performance of such motors with rotor damping. This modeling approach accounts for all saliency effects, and is entirely carried out in the natural abc frame of reference. Thus, it facilitates the process of integration of the modeling of the motor and its associated power electronics. The approach is most effective in the design of damper bar systems for enhancement of the performance of such motors, as demonstrated in the application of this approach to a 15 hp, 120 V, 6-pole, samarium-cobalt, permanent-magnet brushless DC motor. >

HVAC zone control system

Abstract: An HVAC system for a plurality of zones comprising an air handling unit including a blower, a plurality of heating stages and a plurality of cooling stages. The air handling unit is connected via ducts to each of the zones, each zone having an air outlet provided with a two-position damper which is either open or closed and a thermostat for providing an input signal to a microprocessor. The microprocessor has outputs for activating motors to move the dampers and outputs for activating the heating and cooling stages. The system includes an automatic mode of operation in which the microprocessor controls the number of stages of heating or cooling which are energized in dependence on the difference between the number of zone therostats calling for heating and the number of zone thermostats calling for cooling.

Variable stiffness oil film damper

Abstract: The critical speed of a bearing supported rotating shaft is changed or controlled by dimensioning the oil squeeze film damper so that the volumen of oil is selected to produce a spring rate that when added to the mechanical spring rate will attain the overall spring rate of the system. The spring rate of the oil becomes effective when the volume is at a predetermined value which is at a level higher than heretofore known oil squeeze film dampers.

Air flow damper control system

Abstract: An air flow control system for the dampers of the individual offices or rooms in a group of offices or rooms sharing a common air supply duct with a thermostatic control in but a single one of the offices or rooms. The system includes a motor operated damper in each room or office, the motor being controlled to shut the damper when a signal from a remote transmitter is received by a receiver in a control circuit with the motor. The transmitter is selectively actuated by the individual occupying the particular room or office. The control circuit is activated when the signal is received by the receiver, and after a delay period automatically sends a signal to drive the motor to reopen the damper. The occupant may thus control the closing of the damper when the temperature of the air through the supply duct causes the room to be uncomfortable, and need not be concerned about reopening the damper.

Apparatus and method for supporting a rotating shaft in a rotary machine

Abstract: A rotary machine 10 includes a rotor shaft 40 and a support system 63 for the shaft. The support system includes a spring 68 and viscous damper 70. Means for removing oil from the damper at preselected rotor speeds is provided and in one embodiment permits operating the engine over a rotor speed range which avoids critical speeds.

Multi-disc player

Abstract: A carriage supporting apparatus in a disc player is disclosed which comprises a carriage plate; a holder for supporting the carriage plate; a first damper portion provided at one of the carriage plate and the holder, the first damper portion having an annular surface and a plurality of pleat-like projections formed on the annular surface; a second damper portion provided at remaining one of the holder and the carriage and having an annular portion which confronts, with a space, the pleat-like projections of the first damper portion; and a cup-shaped thin wall portion disposed between the first and second damper portions.

Vibration-proof and earthquake-immue mount system

Abstract: A vibration-proof and earthquake immune mount system connecting machinery or a structure to a foundation which may be subject to external vibrations or earthquakes. The mount system includes a number of mounts operating in conjunction with a number of dampers, and both the mounts and the dampers function regardless of the direction of the external disturbance. In the mount this ominidirectionality is achieved by using a low-friction rolling contact between a ball attached to the machinery or structure and a dished surface attached to the foundation. Damping is provided by eddy current dissipation when a conductor plate attached to the structure of machinery and free to move in two directions is placed between the poles of an electromagnet which is integral with the foundation, and activated by a controller energized when a sensor detects motion of the foundation.

Torsion bar scanner with damping

Abstract: A resonant scanner has at least one torsionally rigid damper located at at least one torsional node point of a torsion bar. At least one node of an unwanted vibrational mode is determined to be at a distinct node point, whereby the damper damps the unwanted vibrations while passing desired torsional oscillations. The damper serves as the only physical coupling of the torsion bar to the housing and damps transmission of vibrations into and out of the scanner. One or both ends of the torsion bar may be configured as the rotor of a motor. The rotor fits within but is not physically coupled to a bobbin coupled to the frame. Two coils are wound on the bobbin at approximate right angles to each other to minimize a cross-coupling between the coils.

Automotive air-conditioner

Abstract: An automotive air-conditioner has a motor-driven centrifugal fan and a casing accommodating the fan and having first and second wall portions adjacent to axially opposite open ends of the fan, respectively. A fresh-air inlet and a first recirculated-air inlet are formed in the first wall portion, while a second recirculated-air inlet is formed in the second wall portion to increase flow of recirculated-air sucked into the fan during a recirculation mode of air-conditioner operation. The fresh-air inlet and the first recirculated-air inlet are selectively opened and closed by a servo-actuated damper, while the second recirculated-air inlet is closed and opened by another servo-actuated damper operatively linked to the first-mentioned damper.

Hydraulic damper with oil lock mechanism

Abstract: A hydraulic damper has an oil lock mechanism for preventing bottoming when the hydraulic damper is fully compressed The hydraulic damper also includes an outer tube, an inner tube, a cylinder movable with the inner tube, a piston rod movable with the outer tube, a piston fixed to a distal end of the piston rod, and a coil spring disposed in the inner tube The oil lock mechanism comprises an oil lock piece mounted on an upper end of the cylinder, and an oil lock tube disposed concentrically between the cylinder and the inner tube and having a larger-diameter portion which can be spaced from the oil lock piece when the hydraulic damper is extended and a smaller-diameter portion which can be held in sliding contact with the oil lock piece when the hydraulic damper is compressed

Optimal Performance of Variable Component Suspensions

Abstract: SUMMARY Most vehicle suspension systems use fixed passive components that offer a compromise in performance between sprung mass isolation, suspension travel, and tireroad contact force. Recently, systems with discretely adjustable dampers and air springs been added to production vehicles. Active and semi-active damping concepts for vehicle suspensions have also been studied theoretically and with physical prototypes. This paper examines the optimal performance comparisons of variable component suspensions, including active damping and full-state feedback, for “quartercar” heave models. Two and three dimensional optimizations are computed using performance indicators to find the component parameters (control gains) that provide “optimal” performance for statistically described roadway inputs. The effects of performance weighting and feedback configuration are examined. Active damping is shown to be mainly important for vehicle isolation. A passive vehicle suspension can control suspension travel and tire c...

Multi-disc damper using viscous fluid

Abstract: A damper comprising within a casing filled with viscous fluid a number of movable discs to be moved in response to the transmitted external force and a number of not interlocked fixed discs arranged in an alternative arrangement, wherein both movable and fixed discs are axially deflectable can maintain even clearances between the movable and the fixed discs due to the alignment effect of the discs without undergoing unreasonable stress that can damage the discs. The allowable limit of deflection of the fixed and movable discs can be made adjustable so as to modify the total drag of the damper. Sources of resilient restoring force may be provided to enhance the capability of adjustment. Moreover, the number or the size of the movable and/or the fixed discs can be made alterable to effectively modify the drag of the damper.

Hydraulic damper with variable operating characteristics

Abstract: A damper includes a cylinder containing a hydraulic fluid inside which is a piston defining first and second chambers in the cylinder, the second chamber containing the piston rod. A hydraulic fluid reservoir communicates selectively with the first chamber. A reference chamber contains a gas at substantially constant pressure. A control valve is acted on by the pressure of fluid in the first chamber (tending to open the valve), by a return spring, by the pressure in the reference chamber and by the pressure of fluid in the second chamber (tending to close the valve). A flow restrictor between the reservoir and the first chamber enables hydraulic fluid to flow only from the first chamber to the reservoir. It defines a control pressure to open the valve in response to the rate of inward movement of the piston rod exceeding a predetermined limit value. The flow rate permitted by the flow restrictor is variable so that the valve can open at rates of inward movement different to the predetermined limit value. This varies the damper characteristics in compression. The damper characteristics can also be varied in expansion.

Slow delivery injection device

Abstract: A self-contained device (30) which holds the body (42) of a syringe generally axially aligned with an internal damper unit (37) having an enveloping tension spring (12) acting between a base part of the device (30) and a piston (35) which generally houses the damper (37) and spring (12). The damper (37) includes an externally adjustable damping control (39) for setting the damping resistance to compression of the damper (37). Extension of the damper (37) offers substantially no resistance other than that required to extend the spring (12). The device can be loaded with a filled syringe (42) and will then slowly discharge the syringe at a selectable rate according to the setting of dial (39).

Torque converter provided with vibration damper

Abstract: A torque converter provided with a vibration damper includes an input member, an pump connected to the input member, a turbine located between the pump and the input member, a lock-up clutch disk frictionally engagable with the input member, an output shaft connected to the turbine and the lock-up clutch disk, and a damper mechanism disposed between the radially outer portions of the turbine and the lock-up clutch disk. The damper mechanism includes a damper weight rotatably and concentrically arranged with respect to the input member and the output shaft, a centrifugal clutch including an output member, a centrifugal weight adapted to be frictionally engaged with the output member by a centrifugal force and a weight support fixed to the turbine and radially movably supporting the centrifugal weight, and a damper spring circumferentially connecting the output member of the centrifugal clutch to the damper weight.

Air conditioner for automobile

Abstract: PURPOSE:To achieve a comfortable air-conditioning effect, by feeding air flow of target temperature corresponding to the sunshine in respective areas through respective air supply ducts to respective air supply areas in an automobile, thereby correcting the body temperature difference due to the difference of sunshine effectively. CONSTITUTION:A setting temperature from a temperature setter 13, an outer air temperature and an indoor temperature from outer air temperature and indoor air temperature sensors 14, 15 and the sunshine from respective sunshine sensors 161, 162 disposed respectively at the driver seat 21 and the assistant seat 22 are inputted to a control means 12. Then a target temperature of required breezing air is operated and respective dampers 111, 112 are controlled to required target openings by respective drive circuits 11a. A target air flow is obtained corresponding to said target temperature of the breezing air, and required voltage is applied to respective drive circuits 8b for controlling the voltage being applied onto respective motors 8a in respective fans 81, 82 for feeding air to respective air ducts 31, 32 at the driver seat 21 side and the assistant seat 22 side.

Refrigerator with a malfunction detection system

Abstract: A refrigerator comprises a damper controlling inflow of cold air into a compartment thereof, a temperature sensor for detecting the temperature within the compartment, a damper drive device for driving the damper in accordance with the detected temperature in the compartment, a damper position detection device for detecting the open state and the closed state of the damper, a heater for defrosting the damper, an abnormality detection device, and a malfunction detection device. The abnormality detection device monitors the time that the damper drive device drives the damper, and when the driven time reaches a predetermined value, energizes the heater to defrost the damper. The malfunction detection device monitors the time that the heater is energized, and when the energization time of the heater reaches a predetermined value, deenergizes the heater.

Air damper assembly for refrigerator/freezer

Abstract: A food compartment (I) and a freezer compartment (II) are both cooled by an evaporator coil mounted in the freezer compartment. An air damper assembly selectively allows cold air to flow from the freezer compartment to the food compartment to maintain a selected temperature in the food compartment. The air damper assembly includes a damper door (101) which is slidably mounted to a housing (110) to provide sufficient motive force to drive the damper door to one of the open and closed positions. The damper door is frictionally retained in the selected one of the opened and closed positions until a like momentary electrical pulse is applied to the other coil to drive the damper door to the other position. Optionally, momentary pulses may be applied intermittently to the same coil to assure that the door remains in the selected opened or closed position.

Automotive air conditioning system

Abstract: A damper position control device for an automotive air conditioning system having a lock release mechanism for the drive shaft of a motor which controls the angular position of an air mix damper. A damper position control device is disclosed which controls the angular position of an air mix damper. The damper position control device includes a motor actuator which drives the air mix damper and a control circuit. The motor actuator includes a drive motor for the air mix damper and a rotation control device including a regulator which regulates the upper and lower rotational limits of the shaft of the drive motor and a position detector which detects the rotational angle of the shaft. The control circuit controls the motor actuator in accordance with a plurality of detected signals. The control circuit generates a drive signal which drives the motor actuator and further includes a lock detector which detects if the shaft of the motor is locked against rotational motion in a first rotational direction. The control circuit also includes a lock release which releases the motor so as to permit rotational motion in a second rotational direction after the motor as been locked against rotational motion in the first rotational direction if the motor is within a first predetermined angular displacement from the upper rotational limit or within a second predetermined angular displacement from a lower rotational limit and if the drive signal causes the motor to rotate in the second rotational direction.

Device for coupling coil springs compressed in series in a clutch damper

Abstract: A helical coil spring coupler for clutch dampers used in torque converters or clutches wherein the coil springs are compressed in series alignment end-to-end in an arcuate channel. Each coil spring-to-coil spring interface has a ball and socket coupling attached to the springs and providing force transmission axially through each coil. The spring end coils are fully supported by a flange of the couplings; preventing spring end coil breakage.

A Comparison of Identification Methods for Estimating Squeeze-Film Damper Coefficients

Abstract: Comparaison entre les differentes methodes d'identification des parametres dynamiques des amortisseurs a film comprime

High excursion torsional vibration damper for controlled energy absorption

Abstract: A long travel damper having variable friction lag comprising a torque input cover plate and a torque output driven plate, a plurality of springs arranged on a circular spring guide for cushioning torque delivery between the cover plate and the driven plate, the springs having a large L/D ratio, and a friction lag clutch adapted to be actuated by cam plates connected respectively to the cover plate and the driven plate whereby the clutch is applied with a variable force that depends upon relative angular displacement of the cam plates.

Impact of the addition of a rotor-mounted damper bar cage on the performance of samarium-cobalt permanent magnet brushless DC motor systems

Abstract: The impact of the addition of rotor-mounted amortisseur damper bar cages on the performance of permanent magnet brushless DC motors is investigated. Extension of models in previous papers is used to include the effects of the damper bar cage for a 15 hp, 120 V, 6-pole motor system for which ample test data were available. The results obtained in the course of this investigation showed no adverse impact for these amortisseur damper bar systems on the overall performance (voltages, currents, losses) of the system throughout the various paths in the motor and power-conditioner circuitry. >