Linde Aktiengesellschaft

Robert Bosch

Mannesmann Aktiengesellschaft

Friedrich Grohe Armaturenfabrik Gmbh+co.

Denison Hydraulik Gmbh

Wolfgang Backe

Hubertus Murrenhoff

Franz Weingarten

Egbert Schneider

Wolf-Dieter Goedecke

Alfred Langen

Reinhard Schwenzer

Thomas Karte

Robert Klenk

Bernd Killing

August Layer

Marcus Jarchow

Christoph Latour

Alexander Kleist

Heiko Kresse

Yinzenz Haerle

Horst Weidner

This invention relates to a device to reduce pulsations on a hydrostatic positive displacement unit, such as an axial piston machine or a radial piston machine which can be used both as a pump and as a motor. The direction of rotation of the positive displacement unit is reversible and at least one piston is mounted so that it can move longitudinally in a cylinder bore forming a cylinder chamber. The device has a buffer element which can be brought into communication with the cylinder chamber by a connecting channel. It is possible to further optimize the reversing action of the cylinder chambers from the inlet side to the outlet side and to effectively minimize pulsations in a broad bandwidth of operating conditions by increasing the capacity of the buffer element compared to the capacity of an oil-filled buffer element and/or by providing at least one additional connecting channel which connects the cylinder chamber with the buffer element or with a control nodule of the positive displacement unit, whereby a throttling device is located in the other connecting channel. The buffer element may be a hydropneumatic buffer.

Device to reduce pulsations on a hydrostatic positive displacement unit

Pulse impact mechanism, in particular for pulse screwing device

An apparatus and process for monitoring conditions of a control valve including a valve element operated by a drive controlled by a position controller. A spindle extends into a valve chamber through a dynamic seal and connects the valve element to the drive. The condition of the seal is monitored by measuring start-up time, stopping time and distance travelled. The start-up time relates to the time between application of control current to the position controller and sensing movement of the valve element. The stopping time relates to the interval between application of a second control current to the position controller and sensing the valve element has stopped. The distance travelled relates to distance the valve clement travels during the stopping time. A time difference is determined by subtracting the stopping from the starting time and is calibrated to a seal coefficient of friction. The distance travelled is also calibrated to a seal coefficient of friction. These two coefficients of friction are compared whereby a discrepancy indicates a change in air pressure has occurred during valve operation. These measurements are taken prior to and cyclically during valve operation. The coefficient of friction obtained during valve operation is compared with the coefficient of friction obtained prior to valve operation to indicate a change in the condition of the seal. If a change in air pressure occurred during valve operation, the coefficient of friction obtained by calibrating the travel distance is compared with the coefficient of friction obtained prior to valve operation.

Control valve with a drive operated by a pressure medium and a position

The method of making a screw connection includes measuring a torque applied to the screw by a controllable screw driver device and measuring a rotation angle of the screw in individual connection steps during the making of the connection to obtain measured values of the torque and rotation angle; calculating a change in torque over a predetermined rotation angle interval from the measured values and deriving a stiffness parameter from the change in torque divided by the rotation angle interval; calculating a change in rotation angle over a predetermined time interval from measured values of the rotation angle and predetermined time interval and deriving a rotation speed as the rotation angle change divided by the predetermined time interval; analyzing the stiffness parameter and the rotation speed by a fuzzy-logic device to obtain controlling output variables and operating the fuzzy-logic device in one of three operating modes to obtain the controlling output variables and to produce at least one adjusting parameter for the controllable screw driver device to accurately make the connection. The three operating modes of the fuzzy-logic device consist of three association or correlation functions for either a low stiffness mode, a normal stiffness mode and a high stiffness mode of operation or a low rotation speed mode, a normal rotation speed mode and a high rotation speed mode.

Method of making a connection, particulary a screw connection

A directly controlled hydraulic pressure valve includes a valve housing and an outer valve sleeve which is placed in a port of the valve housing. The port is closed by a cover. A cylindrical inflow component is arranged in the interior of the valve sleeve. The inflow component has a first portion whose diameter is smaller than the internal diameter of the valve sleeve and a second portion having a greater diameter, wherein the outer valve sleeve rests with its end face against the second portion. The pressure valve further includes a cup-shaped tubular piston which is longitudinally movably arranged in an annular space between the valve sleeve and the inflow component, wherein the bottom of the tubular piston is located remote from the second portion. An annular groove is formed in the first portion of the inflow component. Axially extending inflow ducts are provided in the end face of the second portion of the inflow component. The inflow ducts connect the annular groove to an inflow bore in the valve housing. A deflection chamber is formed at the outer circumference of the first portion of the inflow component and adjacent the second portion, wherein the deflection chamber is in communication with outlet openings formed in the valve sleeve. The valve control edges are formed by an edge of the annular groove and an adjacent edge of the tubular piston. The valve further includes a device for exerting a force on the inflow component in a direction which is directed opposite the direction of the pressure force in the inflow bore.

Directly controlled hydraulic pressure valve

Control arrangement for regulating the speed of movement of a hydrostatic energy consumer is provided in which the ratio between pressure supplied and power on the output side is constant, in particular, a piston capable of sliding in a cylinder connected to a pressure main line, characterized in that an initial hydrostatic displacement machine is connected between the pressure main line and the consumer and is coupled with a second hydrostatic displacement machine on the shaft side, the second hydrostatic displacement machine is adjustable with respect to its displacement volume per revolution and is connected on the one hand to the pressure main line and on the other hand to a chamber carrying a lower pressure, where the adjusting element of this second displacement machine is connected with an r.p.m.-regulating device.

Control arrangements for regulating the speed of a hydrostatic energy

A control and regulating arrangement for an adjustable hydrostatic unit is provided in which the regulating device has an auxiliary control constant pump in the feed line of which there is a restrictor, in which case the pressure retained in front of the latter acts on a pressure chamber in which a regulating piston capable of sliding against the force of a spring and which influences the position of a regulating piston connected with the final control element of the hydrostatic unit and capable of sliding in a regulating cylinder is capable of sliding, characterized in that the unit is a hydrostatic motor and the auxiliary control pump is connected to its output shaft.

Control and regulating means for an adjustable hydrostatic unit

A hydrostatic drive system is provided with an adjustable hydraulic motor operatively connected between a high pressure main line and a low pressure line and equipped with a control arrangement that influences the setting in an r.p.m.-dependent manner, the improvement comprising a safety means that limits the stream flowing through the hydraulic motor.

Hydrostatic drive systems

A shower head which provides a pulsating output utilizes a swirl chamber to impart a swirl to the water flow. The use of water driven parts is thereby eliminated.

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Aachen, Germany

Wolfgang Backe