Abstract: An electrohydraulic valve pilot stage for controlling differential pressure is disclosed. The electrohydraulic valve pilot stage has a housing for protecting the valve; a first and second inlet capable of connection to fluid supplies; a first nozzle and a second nozzle fluidly connected to the inlets; a baseplate attached to the housing and the nozzles; a restraining member attached to the baseplate at a position between the first nozzle and the second nozzle; a pivot pin; a flapper restrained by the restraining member and having a first end and a second end, the flapper pivotably mounted on the pivot pin; and a null adjust pin mounted in a pivot pin contact capable position for adjusting the position of the ends of the flapper relative to the nozzles.

Abstract: An improved pilot stage includes a flapper having first and second ends, first and second nozzles in fluid communication with the first and second ends, and a magnetic torque motor having a first coil which is magnetically coupled to the first end of the flapper. An input current to the first coil creates a magnetic torque on the flapper, causing the flapper to pivot. The torque input from the magnetic circuit is reflected through the pivot to create a balancing differential pressure output at the nozzles proportional to the input electrical signal. The flapper does not require a torsion bar (or tube) pivot or a separate armature, as required by functionally similar pilot stages.

Abstract: A lubricant for a wire which is first insulated by means, of a lacquer coating, the wire being used for forming the stator windings of an electrical refrigerating compressor. The lubricant consists of one or more compounds of the formula CH3—Xn—R, wherein X is a linear or branched hydrocarbon group with n carbon atoms, wherein n is up to 22, and R may be hydrogen or a plurality of different radicals, either in a pure form or dissolved in a solvent. The lubricant is applied to the wire to reduce its coefficient of friction, and it is remarkable for its compatibility with the environmentally unharmful refrigerants, such as R134a (1,1,1,2-tetrafluoroethane).

Abstract: A flowmeter and a method of determining the mass flow rate. The flowmeter has a first measuring tube and a second measuring tube which are arranged in a common housing and are connected to one another mechanically. Also provided are an excitation device for exciting the measuring tubes to oscillation, and a detector device for detecting oscillation parameters which is connected to an evaluating device, which determines a mass flow rate signal for each measuring tube from output signals from the detector device. The object is to improve the measuring accuracy in cases in which identical conditions do not prevail in the measuring tubes. For that purpose, an amplitude detecting device is provided which detects the amplitude of the oscillation of each measuring tube, and a correcting device is connected to the evaluating device, which correcting device has a flow input and an amplitude input for each measuring tube.

Abstract: An electromagnetic actuator, especially for the closure member of a valve, contains a solenoid unit, which has a cylindrical cavity closed at one end and open at the other end. An axially introduced guide tube for a magnetically movable armature is arrestable in the cavity by means of a securing device engageable in a first recess under spring force. To simplify connection of the actuator with and separation of the actuator from the component to be adjusted, provision is made for the securing device to lie completely within the solenoid unit and to snap automatically into the first recess when the guide tube is moved into a desired position in the cavity of the solenoid unit.

Abstract: A heating system has several heating devices with valves, controlled in dependence of the temperature, in different rooms, with the heating devices being supplied by a supply device with an adjusting member which acts upon a supply temperature. A control device activates the adjusting member. A heat requirement in the rooms is detected and the supply temperature is adapted accordingly. To keep the energy consumption low, a counter detects the number of rooms in which a heat requirement exists. The supply temperature is increased by a value which corresponds to a product of the number of rooms and a predetermined first temperature difference when the number of rooms is higher than zero. When the number of rooms is equal to zero, the supply temperature is decreased by a predetermined second temperature difference.

Abstract: Hydraulic steering arrangement (15) with a steering handwheel (2), which is connected with a manual. pump (3), a pump (18) supplying hydraulic fluid, a steering motor (12) and a steering valve (15) arranged between pump (18) and steering motor (12) and having a valve element (20) steering the flow of hydraulic fluid between the pump (18) and the steering motor (12), the valve element (20) being displaceable by hydraulic pressures originating from the manual pump. In such a steering arrangement it is wanted to create the opportunity of implementing various functions, without having to abandon the ordinary hydraulic control. For this purpose, the valve element (20) has an additional drive (31).

Abstract: A loop flushing circuit includes a loop flushing valve that is connected to the low pressure system line in a hydrostatic transmission for selectively bleeding fluid therefrom to the case drain without relying on a shuttle valve to identify the low pressure line. The loop flushing valve is adaptable to electrical or electro-hydraulic actuation by a microcontroller. Thus, the timing of loop flushing can be controlled based upon various system operating conditions or input values. Loop flushing with this circuit avoids adversely impacting control characteristics of the transmission, can be defeated around neutral, and can provide single-sided loop flushing.

Abstract: A hydraulic piston for a cylinder block of a hydrostatic power unit has an elongated cylindrical body with first and second ends. An elongated cavity is formed in the body. A cap is adhered to the body to close the cavity. The cap has an external shape to facilitate the operative engagement thereof with a slipper, which is in subsequent engagement with a swashplate mounted adjacent the cylinder block. The piston has an elongated first conduit formed in the body which is separate from the cavity and extends between the opposite ends thereof. The conduit terminates in registering communication with a second conduit in the cap thereof to permit transmission of oil through the conduit without invading the volume of the cavity. The cap preferably has a tapered surface on the inner end thereof engaging a compatible shaped surface on an adjacent end of the body to center and align the cap with the body.

Abstract: The invention concerns a hydraulic valve arrangement with locking function. It has a control valve (9), which in two operating positions (11, 12) connects one motor connection (A) with a pump connection and a second motor connection (B) with a tank connection and vice versa, and in a locking position (10) separates both motor connections (A, B) from pump and tank connection. Further, there are two lock valves (16, 17), each connected between the control valve (9) and one of the motor connections (A, B).

Abstract: A heating system having, in at least one heatable room, at least one first heating device and a second heating device, with the second heating device being of a kind which differs from that of the first heating device, and with both heating devices being controlled. To improve the comfort feeling of a consumer, the two heating devices and their control circuits are coupled with each other, and a change of a parameter in one control circuit causes a corresponding change of a parameter in the other control circuit.

Abstract: The invention concerns a rotary slide set for a hydraulic steering arrangement with an outer rotary slide and an inner rotary slide arranged in the outer rotary slide, and having in its surface tank grooves, which are, at least in predetermined rotary positions, connected with a low pressure connection, and at least one through-opening in its wall, each overlapping, at least partly, a tank groove. In a rotary slide set of this kind it is desired to avoid jamming between the inner and the outer rotary slides. For this purpose, surface recesses have been made at the remaining tank grooves to serve as balancing areas.

Abstract: A hydrostatic vehicle drive has a control (5) for controlling an output torque of the drive and another control device (5) for controlling the output torque of a hydrostatic drive, the control device (5) having a controllable pressure-limiting valve (6) by means of which the working pressure can be adjusted and which is used for sensitive control of the output torque of a hydraulic motor (3). The pressure-limiting valve (6) can be controlled by a proportionally adjustable pressure-reducing valve (7).

Abstract: The invention relates to an electric motor, comprising a rotor (1). One side of said rotor (1) is mounted in a stator (3) by means of a bearing (2) and the rotor tapers away conically from said stator in an axial direction, forming an air gap (4) between the latter (3) and the rotor. The width of said gap increases in an axial direction, moving away from the bearing (2). The aim of the invention is to achieve improved operating efficiency using a conically designed rotor.

Abstract: A method for monitoring a rotational angle sensor on an electrical machine. It is desired to provide a method that enables fault detection at both high speeds and low speeds of the rotor. The electrical power of the machine is measured and a power value is estimated using the output signal of the rotational angle sensor, a residual being formed from the measured power and the estimated power and the time curve of the residual being monitored.

Abstract: A hydraulic neutral cold start control valve for a variable displacement hydraulic unit includes a housing with a spool bore and an intersecting signal pressure passage therein. A spool is disposed in the bore and is mechanically biased to a closed or neutral position of the valve by a pair of opposing springs. A plunger is associated with one of the springs and has a surface that usually sealingly contacts one end of the spool but extends radially therebeyond such that it is in fluid communication with the signal pressure passage. When the signal pressure exceeds a threshold value, the pressure forces the plunger to separate from the end of the spool. Then the movement of the spool becomes proportional to the signal pressure, which is desirable for normal operation and control of the hydraulic unit.

Abstract: A system and method for connectionless sensing of the physical parameters of a shaft that is capable of continuous rotation. The system involving placing a circuit assembly on the rotating shaft, powering the circuit assembly through energy transferred from a stator coil across a gap to a rotor coil, sensing physical parameter data on the shaft and communicating this data across the gap from the rotor coil to a stator coil.

Abstract: A vehicle driving arrangement is provided which has at least two driven wheels, the driving torques of which can be individually regulated by a control device, the control device being connected to a sensor arrangement comprising at least one sensor. Using such a driving arrangement, wheel slip is to be prevented. For that purpose, using a signal of the sensor arrangement, the control device continuously ascertains a maximum torque for each wheel, continuously ascertains the driving torque of each wheel and reduces the driving torque by the appropriate amount when the driving torque ascertained no longer complies with a predetermined limit of difference from the maximum torque.

Abstract: A method to provide a smooth shift during mode changes of an HMT when using mechanical clutches by reducing the power into the transmission momentarily when a shift is initiated by cutting fuel to the engine, and also reducing power in the hydrostatic transmission by crossporting the fluid circuit, and then reapplying power to both the engine and the transmission after the clutch has been shifted.

Abstract: A swashplate assist mechanism for dynamically varying swashplate moments in a multiple piston hydraulic unit includes a valve means disposed in the swashplate and defining a variable orifice for metering fluid from at least one of the pistons; and means for generating a control error signal to the valve means so as to adjust the size of the variable orifice based upon the control error signal. When fluid is metered from a leading piston to a trailing piston near one or more of the pressure transition zones, or when fluid is metered from a trailing piston to a leading piston near the opposite transition zones, the swashplate moments can be reduced.