Showing papers on "Damping torque published in 1981"

Prediction of Ship Roll Damping. A State of the Art

Abstract: : Various methods for predicting the roll damping of a ship at forward speed are discussed. In particular, a simple method and a component analysis are described. The component analysis assumes that the damping is composed of friction damping, eddy damping, lift damping, wave damping, normal-force damping of bilge, keel, hull pressure damping due to bilge keels, and wave damping of bilge keels. Formulas for these components are derived from theoretical and experimental considerations. A listing of a computer program used to compute roll damping is included as an Appendix.

Torque generated by orthogonal acoustic waves—Theory

Abstract: An analytical calculation of the torque generated by orthogonal waves is reported. This torque is a result of a viscous effect, rather than the Bernoulli effect as in Rayleigh's torque. The agreement between the reported experimental values and this calculation is excellent.

Compound damper assembly for an automatic transmission

Abstract: A damper assembly for cushioning the application of a torque delivery clutch in a torque converter transmission wherein the converter provides a complementary hydrokinetic torque delivery path, the damper assembly including a pair of cushioning springs acting in parallel and a third spring arranged in series relationship with respect to the paired cushioning springs, the spring rates being chosen to provide dampening forces that vary nonlinearly with the magnitude of the torque delivered through the damper.

Extended travel damper in a lock-up clutch for a torque converter

Abstract: An extended travel vibration damper for a lock-up clutch utilized in a torque converter where both the clutch friction surfaces and the damper structure are located radially outwardly in the torque converter housing, with the damper being formed of a plurality of annular members with damper springs to provide a compact structure where there is limited space in the torque converter.

The Principles of Eliminating Pulsating Torque in Current Source Inverter Induction Motor Systems

Abstract: The problem of reducing the pulsating torque in current source inverter induction motor systems is investigated. Two typical approaches presented in recent publications are analyzed by making clear 1) the correlation among the current harmonics and the torque harmonics, and 2) the conceptual contradiction existing between these two approaches. By synthesizing the analyzed results, fundamental principles for treating the current harmonics and torque harmonics are established. In addition, the method for evaluating the degree of torque ripple is described, along with a proposed criterion for torque ripple content. By applying this criterion to these two approaches, objective estimates of degree of torque pulsations, which were unfeasible so far, are now made possible.

Rotary hydraulic damper

Abstract: Relative motion between movable parts is damped by way of a hydraulic damper having radial vanes in a hydraulic damping fluid filled working chamber and dividing the chamber into subchambers which respectively increase and decrease in volume in response to torsional movements of the vanes in the working chamber during relative rotation of subassemblies of the damper. Damping is effected by controlled displacement of the hydraulic damping fluid between the subchambers through restricted orifices across an edge of the vanes during torsional movements of the vanes responsive to relative motion of the parts to be damped. Damping may be provided in either direction of rotation. Another level or no damping may be provided in the opposite direction of rotation. Substantially equal damping may be effected in both directions of rotation. A range of adjustments of the restricted orifices is provided for. The damper may be equipped with an overload pressure relief device.

Vibration damper for machine part oscillating linear motion - has mass in viscoelastic liq., whose physical parameters meet specified equation

Abstract: The vibration damper is intended for damping the oscillating linear motion of a machine component. It comprises two relatively movable parts (1,2;4) having surfaces parallel to the direction of oscillation separated by a gap. The latter is filled with a visco-elastic liquid (5), with a specified modulus of shear rigidity and viscosity. One part (1,2) is fixed (3) to the component and the other one (4) to the damping mass, whilst the effective surface area of the other part does not exceed that of the fixed part. For optimum damping effect over a wide frequency range, the parameters are selected to meet specified equation.

Measurement of Electromagnetic Air Gap Torque Produced by a Synchronous Motor during Starting

Abstract: At the present time there is no standard test procedure for the determination of the magnitude of the time varying (pulsating) component of electromagnetic air gap torque produced by a synchronous motor during the starting period. The theoretical basis and/or limitations of various test methods currently used to determine the magnitude of torque pulsations are summarized in this paper, with emphasis placed on methods utilizing measurements of electrical quantities (i.e., flux, current) to determine torque. The results of tests performed on a 100 horsepower, 1200 rpm synchronous motor indicate satisfactory correlation between the power input method, the search coil method, and an experimental method of torque measurement.

Line-pressure control method for v-belt type stepless transmission

Abstract: PURPOSE:To aim at improvement in the service lift of a V-belt still longer and in power transmission efficiency, by calculating the engine torque out of engine operating conditions on the basis of engine power torque characteristics stored in a microcomputer, while setting the line-pressure in accordance with the calculated value and a reduction ratio. CONSTITUTION:Detected values from both a throttle opening sensor 27 and an engine speed sensor 26 are inputted into a central controller 32 while such engine torque as being corresponding to other of these detected values is read from engine power torque charcteristics memorized in advance and stored into a memory 34. Next, in accordane with the detected values of a driven pulley speed sensor 29 and the engine speed sensor 26, a reduction ratio is calculated, and torque motor voltage values for line-pressure setting use are read out of this reduction ratio and the prestored engine torque. And, according to these values, a torque motor 16 of a line-pressure adjusting valve is controlled.

Power transmission configuration having continuous variable progression of gear reduction ratios

Abstract: This invention relates to a power transmission apparatus for flexibly coupling a power source to its intended torque load. This apparatus is addressed to producing an infinitely flexible ratio of gear reduction while continuously maintaining economical, solid contact gear meshings. The simultaneous selection of division ratios, and of optional torque transfer channels, while splitting the input torque provides the two torque components needed for composing the optimum output torque ratio. A plurality of dual journallings permit an annularly torqued rotation to progressively supplement and then replace, the torque from the epicyclic gear reduction rotations. Multiple progressions of infinitely variable reduction ratios selectively activate the amount of input torque energy deflected from the gear reduction apparatus, into a direct torquing of the output shaft. The continuous infinite selectivity of a controlling impedance within the meshings of the gear reduction apparatus, as it responds to external control sensors or to manual selection, determines the gear reduction ratio of the two torque supplements recombined. The ratio of gear reduction is, therefore, continuously responsive to a changing torque load.

Optimum Distribution of Additive Damping for Vibrating Beam Structures

Abstract: : Cost and weight effectiveness of concentrated and distributed additive damping has been studied for linear systems (discrete and continuous) under prescribed harmonic loads and/or displacements. Increases in stiffness and mass due to the additive damping are included. Redistribution of an initially uniformly applied additive damping (viscoelastic layer) has been numerically and experimentally investigated for beam structures. An optimal redistribution has typically been found to reduce amplitudes of resonant responses by about 50 percent (level reduction by 6 dB) with the cost or weight of the damping treatment kept constant. One application has been to vibration isolation of a damped skeletal light-weight machine foundation. (Author)

Input torque control for a variable displacement hydraulic transmission

Abstract: A torque control for a drive system having a hydraulic transmission connectable to a prime mover (30) and having a pair of hydraulically-connected displacement devices V and F, with one device having variable displacement, a torque sensor (35) generates a torque signal representative of prime mover output torque in either driving or braking mode, torque demand generators (47,47') generate a torque demand signal selectively in either driving or braking modes, a governor valve (63) compares the torque signals and generates a control signal and a control servo 17, responsive to the control signal, controls the displacement of the variable displacement device V to eliminate any difference in torque signals.

Three speed automatic transmission with split torque delivery paths in the two high speed ratios

Abstract: A hydrokinetic power transmission mechanism having a torque converter (18) and two simple planetary gear units (20 and 22) in combination with the torque splitter gear unit (52) wherein the elements of the gearing are arranged with respect to friction torque establishing devices in a compact fashion to provide minimum overall dimensions so that it is adaptable for an automotive vehicle driveline with a fully hydrokinetic low speed accelerating speed ratio and a split torque delivery path during operation in the two higher speed ratios to effect an increased engine fuel economy as a portion of the engine torque is delivered hydrokinetically through the transmission system.

Vibration damper for IC engine - has damper springs to transmit torque between sleeve and hob in clutch

Abstract: The damper is for a rotating drive-output clutch plate (1) of an internal combustion engine. It comprises at least two damper springs (21, 43) to transmit torque. A spring (43) is located between sections (3, 13) which have limited relative rotary movements forwards and in over-run. A spring (21) transmits torque under load and the first spring is used under no-load. A lock (69, 75, 95) controlled by the operation of the engine inhibits subsequent displacement of the no-load torsional vibrational damper (43) during an operation under load.

Variable speed control device for ac motor

Abstract: PURPOSE:To perform high-performance operation for an AC motor at a wide speed range by providing a torque current controller generating an adjusting output so that the difference between the actual value and the command value of a torque current component may become zero. CONSTITUTION:A torque current controlling circuit S is composed of a vector rotary machine 40 operating the actual value iT of torque current for output, a torque current controller 39 adjusting a current angle to averagely zero the deviation between a torque current command value iT and an adding point 42 adding the output in the said controller 39 to an angle control loop (the control section of an inverter 11). And the functions are to povide angle bias for compensating the lag of an actual current angle epsilon against a current angle command epsilon* caused by the lag of inverter commutation and to perform current PWM operation preventing a decrease in the stability of control resulting from a wide commutation interval at low speed and irregular rotation by lower torque pulsation.

Optimum Friction Damping of a Flexible Rotor

Abstract: The dynamic response of a multi-mass, large scale, flexible rotor mounted on anti-friction bearings and a variable force friction damper is investigated both analytically and experimentally. The rotor is a scale model of a gas turbine engine shaft with two critical speeds within its speed range of 0 to 8000 rpm. The experimental results define the under- and over-damped regimes of dynamic rotor response and clearly indicate optimized damping. Analytically both a complete geometric model and a simplified single mass-spring-damper model are formulated. Critical speeds, and imbalance response are calculated for various friction damper parameters. The presence of optimized damping is predicted. The correlation of analytical and experimental results are discussed.Copyright © 1981 by ASME

Machine rotary vibration damper - has mass in viscoelastic liquid specified as function of geometry and liquid characteristics

Abstract: The vibration damper is intended for damping the oscillating rotary motion of a component. It comprises two relatively rotatable parts (1,3; 5) having surfaces parallel to the plane of oscillation separated by a gap. The gap is filled with a visco-elastic liquid (6) with modulus of rigidity and viscosity. One part (1,3) is fixed (via 2) to the component and the other (5) to the damping mass. The effective surface area of the one part (5) does not exceed that of the other (1,3). The damping mass moment of inertial is obtained from a specified formula.

Damping device of miniature ac motor

Abstract: PURPOSE:To permit the supply of retarding torque and damping hold torque without juxtaposing a mechanical brake or a separate DC power source by using a charging circuit for a capacitor flowing a damping current to supply damping hold torque after stopping a motor. CONSTITUTION:With an ON signal for a motor fed to terminals 12, a relay 1-3 is closed to conduct a triac 2 and an AC voltage is applied to an AC motor 10 from a power source 11, 11'. With an input signal from the terminals 12 changed into an OFF signal in this status, the triac 2 becomes nonconductive status. In this way, a triac 8 is conducted to generate damping torque by supplying the AC motor 10 with a DC voltage charged in a capacitor 5. A charging current continues to flow to the capacitor 5 after stopping the motor 10 and damping hold torque will be generated by flowing the DC current to the AC motor 10 in accordance with above process.

Embedded Foundations Under Vertical Vibration

Abstract: In this note, a simplified procedure based on energy consideration, has been developed, for the solution of steady-state vibration of a system with combined viscous and Coulomb friction damping, subjected to frequency in dependent and frequency dependent excitation, which yields results essentially same as the exact solution The proposed method uses results essentially same as the exact solution The proposed method uses equivalent damping which assumes that if the damping in a system is small, the total damping effect can be represented by that of an equivalent damper

A general theory of the parametric reluctance motor

Abstract: The parannetric motor is a variable-reluctance machine which, despite the absence of a rotor winding, operates asynchronously. Although the characteristics of this device have been investigated, a theory which allows for the cyclically varying nature of the rotor speed has not been presented previously. It is shown in the present paper that both the steady torque and the damping torque at the oscillation frequency are produced by the mechanism of parametric excitation. The Manley-Rowe equations are employed to confirm this theory and to study further the mechanism of parametric action in electrical machines.

Torque receiver controller

Abstract: The disclosure describes a device for continuous analog position control of multiple torque receivers by a single low power synchro signal source. The device provides continuous control of the magnitude and direction of current flow between the stators of the controlled torque receiver(s). The current flow produces torque which moves the rotor(s) to the desired position.

On the Damping Coefficients for Sway, Roll and Yaw (I)

Abstract: The measurement and the analysis of the unsteady waves generated by a ship model making sway, yaw and roll motions and simultaneously running with a constant forward velocity are proposed for getting the energy flux of the waves and deriving the wave damping coefficients for those motions. The damping coefficients derived do not include the damping effects caused by the dissipation of energy due to the viscosity of water. Accordingly they can be directly compared with the predictions by the Strip theory.Some examples are presented for the damping coefficients obtained by the wave measurements. The wave damping coefficient for roll is confirmed to be independent of forward speed for greater Ω=Vω/g. and can be predicted fairly well by the Strip theory. The accuracy of the theoretical predictions are revealed, however, to be questionable for the damping coefficient of yaw.