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The present invention relates to a hydraulic assembly including a component group with a hydrostatic positive displacement pump and a motor, wherein the drive shaft of the positive displacement pump can be driven by the motor. A known hydraulic assembly with a hydrostatic positive displacement pump and a motor is known, wherein the housing of the positive displacement pump is fixed to a pump support, with solid sound-insulating material clamped between them. The motor is rigidly fixed to the pump support. The solid sound-insulating material between the housing of the positive displacement pump and the pump support is a molded rubber ring which is pressed onto radially inwardly directed annular projections of the pump support via an annular groove surrounding the outside. In addition, the molded rubber ring is axially clamped between a clamping ring and a flange, the clamping ring and the flange being connected to each other by screws. The housing of the positive displacement pump is fixed to a flange on the end side. The pump bearing has a pump bearing housing which, if necessary, is fixed to a base via a damping track by means of the pump bearing housing. The pump shaft and the motor shaft are connected to each other via a rotationally elastic adapter, so that there is no longer a metallic connection between the positive displacement pump and the motor.

The task of the present invention is to propose such a hydraulic assembly which comprises the following component group with a hydrostatic positive displacement pump and a motor, wherein the drive shaft of the positive displacement pump can be driven by the motor, and the hydraulic assembly is constructed in such a way that each component is subjected to only a small load through vibrations, so that it emits less noise and can be produced in a simple way in a cost-effective manner. This task is therefore solved in a hydraulic assembly which comprises a component group with a positive displacement pump and a motor with hydrostatic pressure, and the pump shaft of the positive displacement pump can be driven by the motor, i.e., an additional inertial mass is provided, the component group with the positive displacement pump and the motor being rigidly fixed to this inertial mass. The hydraulic assembly according to the invention is characterized by very little vibration and very little noise emission at low complexity. Low complexity leads to low manufacturing costs. The natural vibrations of the motor-pump component group are reduced by fixing it to the inertial mass. Thus, the hydraulic assembly vibrates only to a very small extent and is damped passively. Even if positive displacement pumps and motors are mentioned here and below, this should not exclude the positive displacement pump working as a hydraulic motor and the motor working as a generator under certain operating conditions, and the recovery of electrical energy under these operating conditions. In an advantageous design of the hydraulic assembly according to the invention, the pump is rigidly fixed to the inertial mass and carries the motor. The hydraulic assembly positive displacement pump usually has a pump housing and opposite two end sides, the pump housing having one end side and opposite two end sides, on one end side of which a pump shaft is accessible for connection to the motor shaft of the motor. The pump housing is preferably rigidly connected to the inertial mass on the two end sides. The positive displacement pump is used for so-called direct drive. Here, the pump housing is provided not only with an opening and a fixing flange for the shaft penetrating on one end side in the center, but also with openings and fixing flanges on the two end sides. Thus, another positive displacement pump flange of the hydraulic assembly can be connected to a positive displacement pump on the two end sides, and driven by the same motor as one pump. It now appears advantageous that the positive displacement pump is rigidly fixed to the inertial mass, even with directly driven pumps, and the pump is rigidly connected to the inertial mass using fixing flanges on the two end sides. The central openings on the two end sides can be closed by the inertial mass or a separate pressure sealing cover. The two end sides of the pump housing of the hydraulic assembly are usually constructed on a housing part called a connecting plate. If economically justifiable, a connecting plate without direct drive can also be provided with some devices, such as fixing flanges, which are fixed to the inertial mass.

Therefore, a hydraulic assembly is generally disclosed, which has less noise emission and can be constructed compactly and less complexly. By avoiding complex components, such as adapter housings which prevent further transmission of vibrations via adapters and elastic intermediate layers, manufacturing costs are low because parts costs are saved and assembly time is shortened.