Mannesmann Rexroth Corporation

G. L. Rexroth Gmbh

Mannesmann Rexroth Ag

The Rexroth Corporation

Jorg Dantlgraber

Horst Fischer

Reiner Puschel

Horst Kramer

Josef Budel

Alfred Feuser

Dietmar Gossl

Helmut Kunkel

Karl Staub

Klaus Morio

Josef Rub

Lothar Schulz

Albert Muller

Rudolf Schaffer

The present invention relates to a hydro-transformer including a hydraulic machine, a switching valve and a control means. A work port of the switching valve, which may optionally be connected hydraulically with a pressure port of the switching valve or a drain port of the switching valve, is connected with a first port of the hydraulic machine. The second port of the hydraulic machine is in hydraulic connection with a drive member. The switching valve is driven by the control means in response to a signal characterizing the volume flow into the hydraulic machine. Where the driver member is a cylinder, its extension may be carried out at a constant velocity and independently of a load, and energy may be recovered upon retraction. Due to the provision of a further switching valve between the second part of the hydrostatic motor and the drive member, a higher pressure may be generated at the drive member in the presence of a low pressure at the pressure port of the switching valve.

Hydro-transformer

The present invention relates to a drive mechanism for a pump ( ) implemented by means of a drive motor ( ), the rotational speed and torque of which are influenced by a frequency converter ( ). The frequency converter ( ) is arranged on a heat dissipator ( ) confining a flow of the pressure liquid guided to the pump ( ). It is advantageous to also arrange the drive motor ( ) inside the said heat dissipator ( ), for this makes it possible to perform intense forced air cooling of a pump-drive motor system without the necessity of an additional cooling liquid. The drive motor ( ) preferably has a central arrangement inside a tubular heat dissipator and is exposed to the pressure liquid over its entire circumference. Baffles or offset connecting sleeves allow for uniform flow through the entire heat dissipator ( ).

Driving mechanism for a pump

Hydraulic unit

A proportional valve has an output proportional to an electrical input signal. In a preferred embodiment, the valve is actuated by a proportional solenoid having a coil which is controlled by a control signal in proportion to voltage or current. The proportional solenoid is controlled by a relatively high current such as a rectified mains voltage. A control circuit ensures that the coil of the proportional solenoid is not overloaded. Particularly, it ensures that a maximum current value is not exceeded. In this way, the mains supply required in prior art devices may be eliminated.

Control of a proportional valve using mains voltage

A hydraulic circuit for supplying a plurality of series-operated consumers of a hydraulically controlled installation, in particular of an injection molding machine, having a pump with feed-flow pressure control, is described. To be able to slow down greater moving masses with very little expenditure in regard to circuitry and devices, only a portion of the consumers, such as the extruder, the injection unit and possibly the ejector are operated in open circulation, while at least one selected further consumer, such as the clamping unit of the injection molding machine, where a greater mass must be moved in alternating directions, is moved in semi-closed or closed circulation.

Hydraulic circuit for supplying a plurality of series-operated of a

A constructional unit comprising a hydraulic machine having a drive or driven shaft and of a support by which the hydraulic machine is held with the interposition of material which deadens solid-conducted noise. Low noise emission of the hydraulic machine is obtained in the manner that the support extends over the hydraulic machine in particular in the direction towards the shaft and that the hydraulic machine is supported on the support via material which deadens solid-conducted noise, present between its outer wall surface and the support. In this way the noise emission can be reduced in a simple manner.

Constructional unit consisting of a hydraulic machine (hydraulic pump or

The present invention relates to a noise dampening assembly of a hydraulic machine and a drive motor, and provides for a structure comprising a block, in which the hydraulic machine is mounted by means of noise dampening elements.

Hydraulic system

A control motor for a servo valve is provided. The control motor comprises a control element which can carry out a pivotal movement due to an electric input signal supplied to said motor. The movement of the control element causes a corresponding change of hydraulic resistances and, as a consequence, changes in hydraulic output signals of an hydraulic amplifier actuated by said motor.

Servo valve having a piezoelectric element as a control motor

The invention relates to a safety arrangement for a controlled drive which is connected to a conduit with impressed pressure. When the safety arrangement responds the machine is separated via shutoff valves from the inlet and outlet and a via a switchover valve the pivot angle of the machine is set to the maximum value so that the largest possible braking torque can be automatically set.

Exhaust and inlet line brake valves for hydrostatic motor

An electro-hydraulic servo-valve having a valve spool and comprising: an adjustment motor, and a control apparatus for adjusting said adjustment motor to depending on the input nominal value, wherein said adjustment motor transmits its movement directly to the valve spool of the hydraulic valve, and wherein a preferably electrically operating additional drive is provided which will be switched on in case the valve spool gets stuck so as to release the valve spool from its stuck condition.

Servo valve

In general terms the invention provides for a direct actuated pressure regulated vane-type pump having a adjustment piston which is under the influence of the pump pressure. The adjustment piston is coupled to said cam ring by means of a flexible or articulate connection means, or else the adjustment piston itself is of a flexible or articulate design.

Directlly actuated vane-type pump

A control valve for a variable displacement pump is improved so that the levelling of the pressure fluctuations of the pump is better and quicker. For this purpose an additional control piston portion on the control piston of the control valve is used. Corresponding to the deflection of the control piston the constriction cross-section set by the control piston portion between the supply connected to the pump pressure line and a passage leading to the control space of the variable pump is varied so that the pressure rise in the control space of the pump and also the pressure drop is accelerated.

Control valve for a pump with variable displacement volume

The invention relates to a hydraulic vane type pump and to a radial piston pump. The cam ring of said pumps is adapted for horizontal and vertical movement. So as to achieve stable operating conditions for the pump at least within a certain range, a single-piece support body is mounted within the vertical adjustment screw so as to avoid a change in the level of height when the cam ring is moved axially.

Rotary pump with adjustable cam ring

The invention relates to a vane pump having input and output slot means. Either the input slot means or the output slot means are designed such that for a movement of the cam ring into a position of zero excentricity the area of overlap between the input slot means and the output slot means is increased.

Variable capacity vane pump with means to vary the area of overlap

An adjusting arrangement for a vane or radial piston pump in which the forces applied outwardly to the cam ring are compensated by the application of hydraulic pressure to each of a plurality of sections about the ring. System pressure is applied to one section and a regulating pressure to another. A spring or hydraulic arrangement absorb any force differential.

Growing community of inventors

Lohr-Sackenbach, Germany

Jorg Dantlgraber