Showing papers on "Rotational speed published in 1997"

Control system for automatic transmission

Abstract: A control system of an automatic transmission has a fluid transmission apparatus (12) connected to an engine (10); input speed detecting device (49) for detecting an input-end rotational speed of the hydraulic transmission apparatus; output speed detecting device (47) for detecting an output-end rotational speed of the hydraulic transmission apparatus; and drive-wheel idle rotation determining device (93) for determining whether the rotational speed ratio of the output-end rotational speed to the input-end rotational speed is equal to or greater than a predetermined value. If the rotational speed ratio is equal to or greater than the predetermined value, the determining device determines that a drive wheel is idly rotating. Thus the control system has only to calculate the input-end and output-end rotational speeds of the hydraulic transmission apparatus, and does not need to determine a change of the rotational speed of the output shaft of a transmission apparatus. The control system therefore eliminates the need to monitor the rotational speed of the output shaft, enabling quick detection of idle rotation of a drive wheel and, consequently, quick decision as to whether to inhibit a shift.

Damping system for vibrating members

Abstract: The low-density granular fill has a specific gravity less than 1.5, placed in hollow cavities built into turbomachinery blades, vanes, and shafts, and provides effective damping at lower frequencies than conventional passive damping treatment due to its low bulk compressional sound speed. Selected materials used for the granular fill treatment are chosen for specific turbomachinery needs, including temperature of operation. Rotation speed is also a factor because it induces on the granular material an apparent hydrostatic pressure associated with the centripetal acceleration, and sound speed in granular materials is a function of pressure raised to the power 1/n. Preferred designs for placement of low-density granular material in appendages and shafts are found using an iterative design tool based on the Direct Global Stiffness Matrix method.

Permanent magnet direct current (pmdc) machine with integral reconfigurable winding control

Abstract: This PMDC machine concept operates from a constant dc voltage source (30) with maximum torque capacity throughout its rotational speed range. The back electromotive force (back-emf) produced by the machine windings (21) under the constant amplitude air gap (12) field produced by the magnets (15) is controlled by changing the winding configurations in series-parallel combinations (Figs. 3A and 3B). Torque is, thus, controlled from minimum to maximum speed without exceeding winding current capacities and without need to increase driving voltage with speed. A startup and low speed the combined back-emf of series connected windings (21) limit current while producing maximum torque. At higher speeds where back-emf would severely limit torque, the windings are connected in series-parallel combinations for maximum achievable torque without exceeding winding current capacities. To accomplish this, windings (21) concentrated in slots (17) are used. Result is optimum utilization of core magnetics and capability of operating at constant input voltage.

Control apparatus for hydraulically operated vehicular transmission

Abstract: Even if a rotational speed of an engine has already increased due to slipping of a fluid torque converter at the time of start of downshifting, a smooth downshifting is performed. For that purpose, there is obtained a speed change developing degree function K(etrm) of the rotational speed of the engine at the time of start of downshifting, the developing degree being dependent on an increase in the rotational speed of the engine due to slipping in the fluid torque converter. The function K(etrm) is obtained with a speed ratio "etrm" of the fluid torque converter at the time of starting of downshifting as a parameter. A boosting correction value QDNOFFZ is computed by multiplying a reference correction value QDNOFFZO by K(etrm) (step S108-5). The hydraulic pressure of the hydraulic engaging element on the disengaging side during downshifting is boosted by the amount of QDNOFFZ (step S108-6).

Heating apparatus for vehicle

Abstract: A heating apparatus for a vehicle includes a heat exchanger for implementing heat exchange between coolant which has cooled an engine and air directed to a vehicle interior to heat the vehicle interior A viscous heater has a rotor and a heating chamber containing viscous fluid The rotor rotates when being subjected to rotational power of the engine The viscous fluid is subjected to a shear force and is heated when the rotor is subjected to the rotational power The viscous heater heats the coolant fed to the heat exchanger as the viscous fluid in the heating chamber is heated A clutch is operative for selectively permitting and inhibiting transmission of the rotational power from the engine to the rotor A belt transmission device connects the engine and the clutch A physical quantity detecting device is operative for detecting a physical quantity related to a rotational speed of the rotor A control device is operative for controlling the clutch to inhibit the transmission of the rotational power from the engine to the rotor when the physical quantity detected by the physical quantity detecting device is equal to or less than a predetermined value

Heat Transfer Predictions for Rotating U-Shaped Coolant Channels With Skewed Ribs and With Smooth Walls

Abstract: A computational study was performed for the flow and heat transfer in rotating coolant passages with two legs connected with a U-bend. The dimensionless flow conditions and the rotational speed were typical of those in the internal cooling passages of turbine blades. The calculations were performed for two geometries and flow conditions for which experimental heat transfer data were obtained under the NASA HOST project. The first model had smooth surfaces on all walls. The second model had opposing ribs staggered and angled at 45 deg. to the main flow direction on two walls of the legs, corresponding to the coolant passage surfaces adjacent to the pressure and suction surfaces of a turbine airfoil. Results from these calculations were compared with the previous measurements as well as with previous calculations for the nonrotating models at a Reynolds number of 25,000 and a rotation number of 0.24. At these conditions, the predicted heat transfer is known to be strongly influenced by the turbulence and wall models. The differential Reynolds-stress model (RSM) was used for the calculation. Local heat transfer results are presented as well as results averaged over wall segments. The averaged heat transfer predictions were close to the experimental results in the first leg of the channel, while the heat transfer in the second leg was overestimated by RSM. The flow field results showed a large amount of secondary flow in the channels with rotational velocities as large as 90 percent of the mean value. These secondary flows were attributed to the buoyancy effects, the Coriolis forces, the curvature of the bend and the orientation of the skewed ribs. Details of the flow field are discussed. Both the magnitude and the change of the heat transfer were captured well with the calculations for the rotating cases.Copyright © 1997 by ASME

Continuously variable transmission

Abstract: PROBLEM TO BE SOLVED: To reduce a load applied to a continuously variable transmission unit and a summarizer and the size of a device by changing an operation mode of a variable transmission among three or four modes. SOLUTION: A variable transmission is made a first mode by combining a third gear 8 with a fourth gear 10 by a second clutch 9. The maximum speed is obtained in the first mode at the maximum variable speed change ratio of a speed change unit 6. The rotational speed of a driving shaft 7 equals to the rotational speed of the ring gear 14 of the planetary gear row of a summarizer: that is, the driving shaft 7 has a speed synchronized with the ring gear 14. If a third clutch 19 is operated to drive a sixth gear 20 in the first mode while the second clutch 9 is stopped under synchronized speeds, the mode is changed to the second mode. If a fourth clutch 19 is operated to drive an 11th gear 18 in the third mode while the first clutch 3 is stopped under synchronized speeds, the mode is changed to the fourth mode.

Antifriction mounting having a rotational-speed measuring device protected from contamination

Abstract: An antifriction mounting includes a bearing having an inner and an outer ring and rolling bodies between them. A seal closes the lateral side of the bearing between the rings. A pulse generator is rotatable with a rotatable one of the rings, which is either the inner or the outer ring. A non-ferromagnetic cover is outside the pulse generator and also seals the opening into the space between the rings. A rotational speed sensor on or outside the cover scans the pulse generator magnetically without hindrance from the non-ferromagnetic cover. Radio signals may transmit other information besides rotation speed. Appropriate transmitters and receivers for those signals can be placed at the pulse generator and/or the sensor.

A robust capacitive angular speed sensor

Abstract: This paper presents a contactless capacitive angular speed sensor for automotive applications. The sensor is based on a passive rotating electrode placed between two mechanically static and electrically active electrodes. The different characteristics of the charge transfer at various sensor positions is utilized as an input for the calculation of the rotational speed. The main advantages of this low cost system are its capability to operate at high temperatures and humidity as well as its insensitivity to vibrations, dirt, dew and moisture deposited on the three sensor electrodes. The mathematical model of the sensor further enables the optimization of the sensor characteristics for specific applications. Experimental results from a prototype designed for the speed-measurement of a steering-wheel show a relative speed error of /spl plusmn/4% at a resolution better than 1/spl deg//s.

Disk drive device and method of setting rotational speed thereof

Abstract: Vibrations transferred to the outside are lessened and high performance against external vibrations and impact is maintained. Further, data is recorded and reproduced satisfactorily. A CD-ROM drive device is provided which is capable of reproducing data at a standard speed, a quadruple speed and a sextuple speed. When a disk is mounted to the CD-ROM drive device, TOC information is read in a playback state at the standard speed (ST1). Next, the disk is placed in a playback state at the sextuple speed and is set to a state held at a predetermined address position (ST2). It is distinguished using a tracking error signal, a control signal for a spindle motor, etc. whether the disk is either an eccentric disk or an unbalance disk (ST3). When the disk is found not to be either the eccentric disk or the unbalance disk, a playback speed is set to the sextuple speed. On the other hand, when the disk is found to be either the eccentric disk or the unbalance disk, the playback speed is set to the quadruple speed. When the disk is found to be the unbalance disk, the playback speed is reduced to restrain the generation of self-induced vibrations at reproduction.

Wafer scrubbing device

Abstract: A wafer scrubbing device (10) for cleaning the surfaces of a thin disk (W) disposed on a stationary spin chuck (14) employs a double brush arrangement (16) whereby brush (18) rotation induces rotation of the disk (W) to be cleaned and whereby the speed differential between the constant rotational speed of the brushes (18) and the variable rotational speed of the disk (W) due to the relative position of the brushes (18) on the disk (W) causes the scrubbing of both surfaces and the edge of the disk (W).

Control device for internal-combustion engine

Abstract: When the rotation speed of an in-cylinder injection engine 1 reduces to a rotation speed for increasing the amount of air which has been set on a higher rotation speed side than a fuel supply-return rotation speed, the amount of air is increased. Thereafter, when the rotation speed of the in-cylinder injection engine 1 reduces to the fuel supply-return rotation speed, the supply of fuel is resumed in the fuel cut mode to securely prevent the rotation speed from lowering and to reduce a torque down during resumption of fuel-supply and deteriorated fuel consumption.

Sensorless control method and apparatus of permanent magnet synchronous motor

Abstract: A sensorless control method and apparatus of a permanent magnet synchronous motor which enables the designation of the magnetic axis over a whole rotational speed range and enables the rotational speed control continuously regardless of the rotational speed command. The control method is such that when a magnetic axis, d-q axis, which rotates at the true motor rotational speed φR, a designated magnetic axis, η-δ axis of the motor are determined and the rotational speed, φRη of the η-δ axis is found, a distribution gain K1 which is so set as to be reduced in accordance with the increase of the absolute value of the revolution command φRREF and a distribution gain K2 which is so set as to be increased in accordance with the increase of the absolute value of the revolution command φRREF are prepared, the revolution command φRREF is multiplied by K1, the revolution transition value φRP which is obtained from the induced voltage or estimated induced voltage of a synchronous motor is multiplied by K2, and the two products are added to each other to determine the rotational speed φRη the designated magnetic axis, η-δ axis.

Electric wheel drive for a utility vehicle

Abstract: A wheel drive for agricultural or industrial utility vehicles includes an electric motor with an output shaft which drives a final drive gearbox that reduces the rotational speed of the driven wheel. A transmission gearset is arranged between the electric motor and the final drive gearbox, and can be shifted between at least two rotational speed transmission ratios. The wheel drive permits attainment of a wide range of vehicle speeds with the use of low cost commercially available electric motors. The design speed of the electric motor corresponds with the principal operating speed of the vehicle and relatively high vehicle speeds are possible.

Speed and surge control for a low order centrifugal compressor model

Abstract: Previous work on stabilization of compressor surge is extended to include control of the angular velocity of the compressor. First, a low order centrifugal compressor model is presented where the states are mass flow, pressure rise and rotational speed of the spool. Energy transfer considerations are used to develop a compressor characteristic. In order to stabilize equilibriums to the left of the surge line, a close coupled valve is used in series with the compressor. Controllers for the valve pressure drop and spool speed are derived. Semi-global exponential stability is proved using a Lyapunov argument.

Optimum design of high-speed, short journal bearings by mathematical programming

Abstract: Generally, the selection of design variables in bearing design is done by a trial and error method using many design charts. However, it is not so easy to successfully select optimum design variables by such a method, and a considerable amount of working time and cost is needed to complete the optimum design of bearings. In this paper, an optimum design procedure for high-speed, short journal bearings operated in both laminar and turbulent flow regimes is developed based on mathematical programming. Under the short bearing assumption, simplified closed-form design formulas are obtained for the eccentricity ratio, maximum film pressure, fluid film temperature rise, supply lubricant quantity and whirl onset velocity. The radial clearance, slenderness ratio and average viscosity of lubricant, which minimize the weighted sum of fluid film temperature rise and supply lubricant quantity for various combinations of journal rotational speed and applied load, are determined by successive quadratic programming, whi...

A simple approach to flux and speed observation in induction motor drives

Abstract: The stator-flux orientation concept allows very good transient and steady-state performances in induction motor drives. However, this control strategy can be conveniently implemented only if the stator flux is correctly observed in the entire speed range. The authors have developed a simple flux observer that gives very satisfactory results, especially near zero speed, and the approach which has been followed also allows a good speed estimation. The observer has been both simulated and implemented on an experimental system that uses a single chip to control the whole drive system. The experimental results show excellent performances, despite the low computational load.

Generator system for internal combustion engine

Abstract: There is provided a generator system for internal combustion engines, which can produce power efficiently at all times irrespective of the engine speed even for use in an internal combustion engine operated at variable speeds such as a vehicle engine. An AC generator electronic control unit (ACG.ECU) 3 determines a rotation speed N2 of a rotating electromagnetic field to be generated by a rotor 1R based on a mechanical rotation speed N1 of the rotor 1R in an alternator 1 such that the relative speed N of the rotating magnetic field to a stator 1S agrees with the maximum efficiency speed of rotation Nx. Then the ACG.ECU 3 sends the determined value to a rotating electromagnetic field controller 2a. The rotating electromagnetic field controller 2a controls phases of AC power to be supplied to a three-phase coil 11 of the rotor 1R to generate a rotating electromagnetic field with the rotation speed N2.

Differential apparatus with additional speed increasing gear and speed decreasing gear selectively engageable with a single output shaft

Abstract: A differential apparatus comprises: a differential gear (1) rotatably housed in a left end within a carrier case (3); a speed increasing mechanism and reducing mechanism (31) housed within the carrier case (3) in such a manner as to be adjacent to the rear differential apparatus (1), having a speed increasing mechanism (37) for increasing a rotational speed and a speed reducing mechanism (39) for reducing the rotational speed of the input gear (33) connected to a differential case (11) in a parallel manner; a speed increasing and reducing clutches (53) mounted to the carrier case (3) and for connecting and disconnecting the rotation from the input gear (33) which are arranged in a plane crossing to axes of output shafts (21,23) in parallel.

Control system for hybrid vehicles

Abstract: A control system for a hybrid vehicle including a traction motor which drives a drive shaft of the vehicle by electrical energy and has a regenerative function of converting kinetic energy of the drive shaft into electrical energy, a transmission arranged between driving wheels of the vehicle and an internal combustion engine of the vehicle and the traction motor, and a storage battery which supplies electrical energy to the traction motor and stores electrical energy output from the traction motor. A desired output from the traction motor is calculated according to decelerating conditions of the vehicle, and an optimal rotational speed of the traction motor at which the traction motor provides a maximum regeneration output is calculated according to the calculated desired output. The change gear ratio of the transmission is controlled such that the rotational speed of the traction motor is equal to the optimal rotational speed.

Apparatus for detecting rotational speed

Abstract: An apparatus for a rotational speed detecting includes a rotating disc having plural slits in a circumferential direction. A radiant element radiates light rays through the slits. A photodetector receives the rays radiated by the radiant element. Peak detectors detects peak points of the detected signal and a calculator calculates a rotational speed. The photodetector include two photodetectors separated by a distance ΔL.

Method for fabricating a semiconductor device in a magnetron sputtering system

Abstract: Disclosed is a magnetron sputtering system enabling formation of a film of a ferroelectric substance by suppressing occurrence of a magnetic field due to an eddy current. The magnetron sputtering system includes a flat target; magnetic field applying means (magnets), provided in the vicinity of a back surface of the target, for applying a magnetic field to a front surface of the target; and magnetic field rotating means (motor) for rotating the magnetic field applying means so as to rotate the magnetic field applied to the front surface of the target. The magnetic field rotating means is provided with rotational speed varying means (speed controller) for varying the rotational speed of the magnetic field applied by the magnetic field rotating means.

Motor-assisted bicycle

Abstract: The invention provides a motor-assisted bicycle in which a first power transmission system (56) having a first one-way clutch (59) is provided between a crank shaft (33) having crank pedals (32) at both ends thereof and a power transmission member (53) for transmitting a power to a rear wheel (WR), and a second power transmission system (57) having a second one-way clutch (80) is provided between an electrically assisting motor (30) and the power transmission member, wherein operation of the motor (30) is controlled by a control unit on the basis of detected values obtained by a rotational speed detecting means (S R ) and a torque detecting means (S T ), and a rotational speed representative of a bicycle speed in a state in which an assisting force is applied from the motor (30) to the rear wheel can be detected using an inexpensive, small-sized detecting means, and wherein a rotational speed representative of a bicycle speed can be detected using an inexpensive, small-sized detecting means and the motor can be smoothly controlled.

Device for determining the rotational speed

Abstract: Disclosed is a device designed to determine the rotational speed and to be connected to a rotational speed sensor which sends one or two output signals representing, among others, a measure of the Coriolis acceleration and, consequently, a measure of the rotational speed. The inventive device includes a signal processing unit which is used for doing a digital subtraction of the output signals, followed by a digital multiplication with a carrier signal offset in a phasing unit. The digital multiplication is followed by a digital/analogical conversion and a low-pass filtering, which produces eventually an output signal (DR) corresponding to the rotational speed.

Wind driven electrical power generating apparatus

Abstract: A wind driven electrical power generating apparatus includes an armature. The apparatus also includes a wing secured to the armature. The wing defines a pocket having a hub end and an outer end. The width of the pocket monotonically increases from the hub end to the outer end. Moreover, the depth of the pocket monotonically increases from the hub end to the outer end. The wing and the armature produce a relatively large amount of torque during rotation of the armature which is converted to high rotational speed by a gear mechanism thereby driving a generator at a relatively high rotational speed. Such high torque production eliminates the need to rotate the armature at a high rotational speed. Moreover, the configuration of the wing allows the armature to be rotated in the presence of relatively low wind velocities. Hence, the apparatus may be efficiently utilized for electrical power generation in geographic areas which typically experience relatively low wind velocities.

Method and device for identifying kind of tyre

Abstract: A tyre identifying method comprising measuring the rotational speed of each of the four tyres fitted to the wheels of a vehicle; calculating a ratio of front wheel rotation speed to rear wheel rotation speed from the measured value; and identifying the kind of tyre fitted by comparing the calculated front-rear wheel ratio with a function of speed and front-rear wheel ratio prepared on the basis of data from, the tyre whose kind is previously known. Utilisation can be made of the means for measuring the rotation of tyre such as ABS which is equipped on the vehicle control device, thus requiring small initial cost.

Rotating spray nozzle with controlled braking action

Abstract: A spray nozzle head is rotated directly by a turbine which is driven by the pressure of liquid at the inlet of the nozzle. The turbine is supported by a thrust bearing which also acts as a friction brake to cause the rotational speed of the nozzle head to remain substantially constant as the inlet pressure increases through a predetermined range.

Design of an axial flux permanent magnet wind power generator

Abstract: Direct driven variable speed permanent magnet wind power generators (PMWG) have received an increasing amount of attention. The reason for this is the reduced cost of the produced electric power made possible by the elimination of the gearbox and by the use of variable speed increasing the energy capture. Traditionally the gearbox is required to increase the low rotational speed of the turbine (typically 20-40 rpm) up to a speed suitable for a common 4-pole generator (1500 rpm). The removal of the gearbox increases system availability and reduces its weight, losses and the need for maintenance. However, the low rotational speed calls for a generator with a very large number of poles. Furthermore, the generator must naturally be efficient and cost competitive. Due to the variable speed scheme a frequency converter is required to supply the power to a grid. The requirement of a large pole number can be met with permanent magnets which allow small pole pitch. A simple and effective generator structure is realized by the disc type axial flux configuration, the active parts of which are presented. The stator is a toroid wound from iron tape accommodating rectangular coils forming an air gap winding. Rotor discs with attached permanent magnets reside on both sides of the stator. In this paper optimum design based on minimizing the sum of investment and energy loss costs for a 100 kW prototype generator is searched. The investment costs cover only the cost of the active part material while the manufacturing and structural costs are assumed to be constant over the dimensional range studied.