Hydac System Gmbh

Deere & Company

Hydac Technology Corporation

Michael Kühn

Hubertus Schmidt

Marcus Bitter

Reiner Hoffmann

Heinz Peter Huth

A hydropneumatic suspension having at least one suspension cylinder () and at least one hydraulic accumulator configured as a suspension accumulator () has a pilot-actuated valve () for opening or blocking a fluid-carrying connection between the suspension cylinder () and the suspension accumulator (). The pilot-actuated valve () can be moved into the blocked position by a hydraulic actuating assembly (). The hydraulic actuating assembly () taps the fluid pressure between suspension accumulator () and the suspension cylinder (), and forwards it by a switching valve () to an operating side () of the pilot-actuated valve () through a pilot-actuated line (). Another proportional valve (), or such valve connected to the respective associated pilot-actuated line (), can be between one switching valve () and the pilot-actuated valve ().

Hydropneumatic suspension

A suspension device is for at least one drive part () that is to be cushioned. The drive part can be connected to an accumulator device () by a first valve unit () and to a tank connection () by a second valve unit () to transport fluid. The device is provided with a pressure compensation device (), which when actuated compares the respective prevailing pressures in the drive part () and the accumulator device () to generate a common pressure level. This comparison permits the pressure level to be rapidly compensated in advance when the actual suspension is enabled in the form of the accumulator device, in such a way that the suspension pressure employed exactly matches the pressure of the respective drive part in the form of a hydraulic or working cylinder that prevails in the later as a result of the preceding load actuation operations.

Suspension device

A control device, in particular for working machines, such as wheel loaders, excavators or similar devices, includes at least one working tool (), particularly a working shovel that can be actuated by at least one hydraulic working cylinder (). The device has a control block for controlling the hydraulic fluid paths between the working cylinder (), a hydraulic fluid supply (P) and a tank (T). The device also has at least one hydraulic accumulator () and a shut-off or stop valve (). The shut-off valve has a controllable valve member () and is located between the working cylinder () and the accumulator (). The valve member is connected in the transmission position for connecting the accumulator () in order to damp the motion of the working cylinder (). A selector valve () that can be controlled by the control block () is connected in the feed line (), blocking the line () in the non-actuated state. The shut-off valve () is connected in a secondary line () that is connected to the feed line (), The shut-off valve is impinged in the open direction by accumulator pressure, and is decompressed in the closed direction. This permits increased safety to be achieved for working machines, and prevents an excess load from being placed on the damping accumulator.

Control device

A hydraulic arrangement is provided with at least one pressure accumulator for a hydraulic fluid, a hydraulic cylinder with at least one chamber to which pressure can be applied, a connecting line, on the basis of which the at least one accumulator is connected with the chamber, and a control unit. In order to provide an electronic pipe break safety device, an electronically controlled on-off valve is mounted in the connecting line and coupled for receiving control signals from the control unit, and a signal transmitter, which is coupled for monitoring the pressure in the connecting line is also connected to the control unit. If a pressure drop occurs in the connecting line, a signal change is generated by means of the signal transmitter, whereupon the control unit sends a signal effecting movement of the shut-off valve to its closed position.

Growing community of inventors

Wotenitz, Germany

Michael Kühn