Showing papers on "Damper published in 1986"

Approximate dynamic model of embedded foundation in time domain

Abstract: A discrete model to represent the unbounded soil (halfspace) in a soil–structure interaction analysis in the time domain is developed. For each dynamic degree of freedom of the foundation node, the discrete model consists of a mass M0 which is attached to a rigid support with a spring K and with a damper C0. In addition, a free node with the mass M1 is introduced, which is connected to the foundation node with a damper C1. All coefficients are frequency-independent. The discrete model is semi-empirical. It is based on a semi-infinite truncated cone, whereby, after enforcing the static stiffness, the remaining parameters are modified to achieve an optimal fit of the dynamic-stiffness coefficient in the frequency domain. The spring K is equal to the static stiffness. The coefficients appearing in the equations for the dampers C0, C1 and the masses M0, M1 are specified (assuming a homogeneous halfspace) for the disc, the embedded cylinder, the rectangle (also embedded) and the strip. A square on a layer whose stiffness increases with depth resting on a homogeneous halfspace is also treated. For an embedded foundation, eccentricities arise. Material damping increases the damper C0 and the mass M0.

Duct type multizone air conditioning system

Abstract: An air duct type multizone air conditioning system having air dampers and corresponding thermostats in respective zones under the control of a main controller. The main controller can override desired temperatures selected by the corresponding thermostats in any of the zones and automatically detects the number of the number of zones, the presence of an auxiliary heater, and a heat pump, and the presence of an air damper and corresponding thermostat properly located in the same zone. The main controller also receives information regarding the operating cost of the heat pump and the auxiliary heater to ensure their cost-effective use.

Active vibration isolation system employing electro-rheological fluid

Abstract: An active vibration isolation system employing an electro-rheological fluid comprises a damper having a servovalve fluidically coupling a load supporting actuator to an accumulator. The servovalve includes an orificed plate arrangement, across which a voltage potential is impressed in accordance with a command signal derived from response sensors. The viscosity of an electro-rheological fluid contained within the servovalve reacts to the voltage potential so as to regulate the fluid flow. In this manner the damping coefficient is modulated to as to approximate a "sky-hook" damper.

Zoned air conditioning system

Abstract: A zoned air conditioning system using a room air terminal which has the same horizontal dimensions as a floor tile of a raised tile floor such that the terminal may replace one tile in such a floor. The terminal includes a cool air inlet below the floor for drawing in cooling air circulated in the under floor space and a return air inlet in the top surface of the terminal. The cool air and return air is mixed in a mixing chamber and drawn from the mixing chamber by a fan and returned to the room through an outlet vent. The ratio of cool air to return air mixed in the mixing chamber is controlled by a modulating damper which is controlled in response to the temperature of the return air in order to control the room temperature in the region of the terminal in accordance with an adjustable set point. A heater is also provided in the terminal for those occasions where the return air is cooler than the set point.

Apparatus for damping torsional vibrations in the power trains of motor vehicles

Abstract: Apparatus for damping torsional vibrations in the power trains of motor vehicles has a first flywheel connected to the crankshaft of the engine and a second flywheel which is rotatable relative to the first flywheel and can be coupled to the input shaft of the change-speed transmission by a friction clutch. Angular movements of the flywheels relative to each other are opposed by a hydraulic damper, by an elastic damper and by a friction generating device. The hydraulic damper has pairs of chambers for a viscous fluid medium which is caused to flow from one chamber to the other chamber by way of one or more flow restrictors in response to angular movements of the flywheels relative to each other.

Velocity controlled forced air temperature control system

Abstract: A building temperature control system is velocity based, employing the velocity of air flowing into individual zones of temperature control to control temperature of the individual zones, total amount of air supplied to all zones from the air supply system, and the number of heating or cooling units in operation. Set point temperature for a particular zone is compared with actual temperature to generate a target velocity signal proportional to the temperature error. The target velocity signal is compared with actual flow velocity measured by the zone velocity sensor, and the difference between target and sensed velocity is employed to operate an air flow control damper valve until velocity of air flowing into the temperature control zone is equal to the target velocity. For control of total air delivered to all zones, the sum of all sensed zone air flow velocities is subtracted from total fan output capacity, and the difference bypassed through a supply system bypass duct, which it self includes a bypass velocity sensor. For control of the number of heating or cooling units in operation, total output fan capacity is divided into a number of overlapping ranges, and the total air flow demand, as determined by the sum of all sensed zone velocities, is compared to the several ranges, causing a single cooler/heater unit to operate when the total air flow demand is in a first lower range, causing two cooler/heater units to operate when the total air flow demand is in a second higher range, and similarly adding additional cooler/heater units as the total air flow demand increases to third and higher ranges. An air flow velocity sensor has a temperature responsive heat generator that is cooled by flow of cooling air over a heatsink connected to the generator and has its output compared with a reference which responds to ambient air temperature variation.

Vibration damping system for power unit

Abstract: A damper of a vibration damping system is installed to connect a power unit and a vehicle body and disposed independent from power unit mount devices. The damper is positioned in the direction of a tangent line of the direction of roll of the power unit. The damper consists of an elastomeric wall member defining a first fluid chamber and connected to the power unit, and an elastomeric diaphragm member defining a second fluid chamber which is communicated through a communication passage with the first fluid chamber. A liquid is filled in the first and second fluid chambers and the communication passage. The volume of the communication passage is changed in response to engine speed of the power unit, thereby effectively damping vibrations of the power unit in roll direction.

Control method and means for vibration attenuating damper

Abstract: A damper of the semi-active type is controlled such that the damping forces generated by the damper, in response to relative movement between spaced members interconnected by it, are caused to be of minimal (ideally zero) magnitude when the product of the relative displacement between the members and the relative velocity between the members is greater than zero. The foregoing control policy may be implemented by purely mechanical elements, or by electronic elements of relatively simple and inexpensive types.

Observer control means for suspension systems or the like

Abstract: The apparatus is particularly suited for control of the performance of a vehicle suspension system or similar plant having controllable semiactive dampers capable of either high or low damping modes. Different plant modes ensue from different combinations of the damper modes. The control apparatus includes observer devices that model each of the plant modes and produce estimates of the plant output or performance that would be produced in each plant mode. A cost function device identifies the optimal one of the estimates, and the dampers in the real plant are adjusted so as to cause the plant to assume the one of its modes modeled by the observer producing the optimal estimate. In an alternative reduced form of the invention, the functions of the observer and cost function devices are performed by switching function generators that produce switching functions indicative of the estimated worth of the outputs that would be produced by the plant in each of its different modes.

Effect of Damper Modelling and the Fault Clearing Process on Response Torque and Stressing of Turbine-Generator Shafts

Abstract: The paper discusses the effect damper circuit modelling and the current interruption process following clearance of grid network disturbances has on machine transient response. Parameters for a 2-direct-axis and 3-quadrature-axis damper circuit model are given, as are those for lower-order damper model equivalents. Torques obtained following clearance of typical L-L-L and L-L non-ground system disturbances at fault current zeros or by simultaneous interruption for detailed and reduced damper models are illustrated. Further, the effect damper circuit modelling has on peak torque response following clearance of supply network disturbances at fault current zeros, sustained L-L-L and L-L stator terminals short-circuits and worst-case malsynchronisation is depicted.

The Effect of Bearing Support Flexibility on Critical Speed Prediction

Abstract: Some vendors and many users of rotating machinery are arbitrarily reducing the bearing damping by as much as 75 percent in order to accurately predict the location of the first and second lateral critical speeds. This paper shows that if the bearing support flexibility is considered, accurate critical speed predictions are possible without reducing the bearing damping. The equations for the equivalent support stiffness and damping are given for a flexible support spring, mass, and damper in series with the fluid film stiffness and damping properties of a tilting-pad bearing. These equations can easily be incorporated with any synchronous response and/or stability computer program. Examples of test stand results for four production rotors are shown illustrating the accuracy of this method. Presented at the 40th Annual Meeting in Las Vegas, Nevada May 6–9, 1985

Apparatus for counteracting torsional stresses

Abstract: A vibration damping apparatus which is installed in the power train between the crankshaft of an internal combustion engine and the input shaft of a change-speed transmission in a motor vehicle has two coaxial flywheels which are rotatable relative to each other against the opposition of one or more dampers. The damper or dampers are installed in a fluid-containing chamber which is provided in part in one of the flywheels.

Method and apparatus for controlling the suction pressure in a dust collecting duct

Abstract: The invention is concerned with pneumatic apparatus for removing fibers, dust and threads from industrial processes, particularly in the textile industry. In an arrangement in which there is a plurality of collecting heads each associated with a part of a machine from which dust, fibers or threads are likely to be emitted, each of these collectors leads into a common duct which in turn leads to a suction fan and filter. The suction pressure (or any other physical characteristic of the air in the duct which relates to the suction pressure) is detected, and a signal from this detector is compared with a signal corresponding to a desired suction pressure and the output signal from the comparator used to control the speed of the driving motor for the suction fan. In this way, the suction pressure in the duct approximates to a constant pressure, despite variations due to the build-up of material on the filter or other factors such as the opening and closing of dampers controlling the flow of waste material into the duct. Consequently, the fan speed can be set at an optimum value, instead of having to set it at a value which will ensure operation of the system under the worst conditions. Hence, a large energy saving is possible.

Torsional vibration damper

Abstract: A torsional vibration damper comprises a flywheel for an internal combustion engine, with a cavity 3 defined in a radially outermost part 1 of the flywheel, containing a flyring 4. A viscous medium is contained in the gap 7 between the flyring and the walls of the cavity 3, to provide damping by shearing in the viscous medium when relative rotation between the flywheel and flyring occurs. The damper is thus provided in the flywheel itself rather than in a separate damper unit.

Support bearing of a vibration damper or spring strut of a motor vehicle

Abstract: Support bearing of a vibration damper or spring strut of a motor vehicle with a piston rod (2) axially displaceable in a damper outer tube (1), which piston rod is supported on its outer end area by way of an elastic bearing element (4, 4', 4'') on an outer ring (5', 5'', 5''', 5' ) surrounding the piston rod (2). The outer ring can be inserted from the damper side into an opening (6) in the body (13) up to a radial extension of the outer ring and is to be fixed in the opening (6). Fixing is performed in that the outer ring can be positively connected through the opening (6) to a closed circular retaining ring (16, 16', 27, 38) bearing extensively on the edge area of the opening (6) on that side remote from the damper, or in that on its circumference the outer ring has radially elastic sections (rubber ring 49), which grip behind the edge area of the opening (6) on the side remote from the damper and bear extensively on this edge area.

Parametrically controlled active vibration isolation system

Abstract: A parametrically controlled active vibration isolation system comprises a damper (20) having a servovalve (30) fluidically coupling a load supporting actuator (58) to an accumulator (54). The servovalve (30) includes a variable orifice arrangement (60. 62. 36) which regulates the flow therethrough of a hydraulic fluid response to a command signal derived from response sensors (12.14. 70). In this manner the damping coefficient is modulated to as to approximate a "sky-hook" damper.

Performance of Viscoelastic Structural Dampers for the Columbia Center Building

Abstract: Vibratory motion of structures such as buildings, bridges, and floors can be reduced by the use of viscoelastic (V. E. ) dampers. Such dampers transfer part of the vibratory energy of the overall system into heat and dissipate this heat into the surroundings. Damper design requires certain pertinent data. These data are generated by calculation and estimation of basic vibrational characteristics of the structure. They include resonance behavior (frequency, amplitude), amplitude-time distribution of motion, mode of vibration and total energy induced by vibration in the structure. It is also pertinent to study the source of vibration (wind, machinery, etc. ), and its nature. This last information is essential in defining the frequency and duration of oscillatory forces responsible for the vibration. This data enables the designer to decide upon the amount of damping required for a predetermined limit of building deflection under selected conditions.

Torsional vibration damper having springs with progressive characteristics

Abstract: The torsional vibration damper comprises in apertures in an input part and in an output part rotatable in relation to the input part coil thrust springs which couple the input part and the output part together in torsionally elastic fashion. Over a plurality of turns of the coil spring, the diameter of the wire material varies continuously from a first value to a second value. From one end of the spring to the other, it is possible for the diameter to diminish steadily. The diameter can however also either increase or decrease from the middle of the coil sprng towards the two ends. Springs of this type make it possible with relatively minimal structural expenditure to provide torsional vibration dampers which have a progressive characteristic.

Investigation of the Steady-State Response of a Dual-Rotor System With Intershaft Squeeze Film Damper

Abstract: This paper presents an analysis of the steady-state unbalance response of a dual-rotor gas turbine engine with a flexible intershaft squeeze film damper using a simplified transfer matrix method. The simplified transfer matrix method is convenient for the evaluation of the critical speed and response of the rotor system with various supports, shaft coupling, intershaft bearing, etc. The steady-state unbalance response of the rotor system is calculated for different shaft rotation speeds. The damping effects of an intershaft squeeze film damper with different radial clearances under various levels of rotor unbalance are investigated.

Speed control of a variable speed air conditioning system

Abstract: Provision is made in a multiple zone air conditioning system for varying the speed of the compressor to match the load thereon. The differences between the actual temperatures and the set points in the individual zones are monitored and the largest of these differences is periodically selected and applied to a transfer function to obtain a new speed at which the compressor is run. At the same time, the individual dampers within the zones are modulated in response to their respective sensed temperature differences. Provision is also made to vary the speed of the indoor fan in a similar manner.

Characteristics of single and multi-blade dampers for ducted air systems:

Abstract: The inherent characteristics of a damper can be defined in terms of the square root ratio of the loss coefficient at the fully open position to the loss coefficient at any other blade angle. It is ...

Crank damper pulley structure for the internal combustion engine of a car

Abstract: A crank damper pulley structure of an internal combustion engine of a car in which the hub of a pulley, which is removably fixed to the tip of the engine crank shaft and transmits power to auxiliary machinery, such as an alternator, has therearound a damper mass and a damper rubber comprising a torsional damper The hub has a cavity therein which opens to one end of the hub A damper support is fixed in the cavity and a ring-like damper and a ring-like damper mass are superposed axially with the rubber being fixed to the mass and the support in order to constitute a ring-like dynamic damper disposed in the cavity which copes with bending vibration of the crank shaft

Fireplace damper assembly

Abstract: A damper assembly for sealing a vertical fireplace exhaust including a vertical duct having an outlet communicating with the atmosphere for exhaust of fireplace fumes, mounting means mounted on said vertical duct outlet, a damper downstream of said vertical duct outlet operative to block and open said vertical duct outlet and means to open and close said damper. Easily added improvements include a spark screen assembly downstream of said damper and communicating with said vertical duct outlet, electrical actuation of said damper, automatic control of said actuation by temperature and/or smoke detection means, a fan to provide draft assist, and/or a wind protection hood to provide a better draft.

An adjustable hydraulic damper

Abstract: In a two-tube adjustable hydraulic damper an axially displaceable annular piston (23) supports a coil spring (8) which surrounds and is coaxial with the cover tube (6) of the damper. The piston (23) is exposed to the pressure of damping fluid within a lifting cylinder (9) and thereby lifts the vehicle. A simple electrically controlled adjustment of the load- supporting capacity and a load- dependent adjustment of the damping acting in parallel with the damping in extension and contraction is achieved by providing an annular connecting passage (10) which connects the upper working chamber (4) with the compensating chamber (7), the annular passage (10) being in communication with the lifting cylinder (9) through an opening (11), an a valve (13) being provided for closing off a port (12) which leads from the passage (10) into the compensating chamber (7). The valve (13) can be electronically controlled.

Air conditioner for vehicle having blower with auxiliary intake port

Abstract: An air conditioner for a vehicle which has a fan of a centrifugal blower used in the air conditioner, the fan having upper and lower fan secitons split by a shield plate with respect to a rotational shaft direction, a normal air intake port formed at either one side of the upper and lower fan section, an increasing air intake port formed at the other of the upper and lower fan sections, and a damper formed at least in the increasing air intake port, the damper being opened only when air intake quantity is necessarily increased or air intake resistance is necessarily decreased. Thus, the air conditioner can increase the effective air intake volume to raise the efficiency of a blower and to simultaneously obtain sufficient air blowing quantity.

Long travel series damper for continuously variable transmission

Abstract: A long travel series damper assembly for a continuously variable transmission or similar arrangement which maintains minimal contact friction while equalizing manufacturing and loading tolerances without adding additional frictional forces. This assembly runs in a dry environment and includes a hub assembly having a barrel and a pair of hub drive plates (24) encompassing the damper assembly and providing inwardly offset drive straps (32), a flywheel drive plate (11) having radially inwardly extending drive arms (14) corresponding in number to the drive straps, a floating idler divider (73) encompassing the hub barrel and having circumferentially spaced dividers, compression damping springs (83, 83b, 84, 84b) located between the flywheel drive arms, the hub drive straps and the idler dividers, and at least two intermediate retaining rings (35, 55), each of which is capable of movement independent of the hub assembly in one direction of rotation to limit the friction forces of the damper assembly.

Aerodynamic shape with improved lift characteristics

Abstract: An improved aerodynamic shape comprises an essentially planar face portion and leading and trailing edges associated with opposing ends of the face portion to develop a cross-sectionally inverted, pan-shaped enclosure. In conjunction with a damper including a frame and one or more blades pivoted for rotation within the frame, blades provided with the aerodynamic shape of the invention develop increased lift when forced open by escaping air, permitting the blades to be constructed of relatively heavy gauge materials without comprising damper efficiency.

Compact disc damper and method

Abstract: A damper disc made of material having significant loss to vibration and low sound propagation velocity is arranged to be laid over a CD disc and in good contact with its upper surface to suppress and dissipate vibrational energy from the CD disc. The damper is also light opaque and light absorptive. Specific suitable materials are disclosed as well as an embodiment suitable for making the damper available as an after market accessory, and integral part of the CD player, or as an integral part of the CD disc.

Hydraulic damper for vehicles with variable orifice piston valving for varying damping force

Abstract: Rebound and compression damping action of this hydraulic damper is set by rotating a selector plate within the damper piston to a number of positions to control orifice selection in parallel to flow through the disk plate pack and thereby control the rate of oil flow through the piston during rebound.