Pumps – Motor driven – Including means utilizing pump fluid for augmenting cooling,...
Patent
1998-06-10
2000-11-14
Solis, Erick
Pumps
Motor driven
Including means utilizing pump fluid for augmenting cooling,...
F04B 1700
Patent
active
06146113&
DESCRIPTION:
BRIEF SUMMARY
FIELD AND BACKGROUND OF THE INVENTION
The invention concerns from a compact hydraulic unit.
A hydraulic unit with an annular cylindrical pressure medium container, formed by an outer external wall, an inner external wall as well as two end walls and/or end flanges, with a closed electric motor surrounded by the pressure medium container and with a hydraulic pump driveable by an electric motor, is known from DE-GM 82 07 794.
A closed electric motor is used, for example, to prevent small metal parts or current-conducting fluids from entering the interior of the electric motor and causing electrical or mechanical damage there. Closed electric motors are usually cooled by air flowing along their exteriors, with the air stream being generated by a fan wheel.
The hydraulic unit shown in DE-GM 82 07 794 is quite large. The cooling of the electric motor is insufficient for continuous operation of the unit.
SUMMARY OF THE INVENTION
On the other hand, an object of the invention is to provide a compact hydraulic unit with an annular cylindrical pressure medium container, with a closed electric motor, and with a hydraulic pump driveable by the electric motor, the pump being very compact, and with the cooling of the electric motor permitting continuous operation.
According to the invention with a compact hydraulic unit of the above-mentioned type, the pressure medium container fits closely around the electric motor and the inner external wall of the pressure medium container serves as a means of conducting the cooling air stream flowing over the electric motor. The pressure medium container is made to fit closely around the electric motor in two ways. Firstly, a very compact design of the hydraulic unit is achieved. Secondly, the cooling air is conducted over the electric motor and close to it and also flows closely along the housing of the electric motor at the winding heads that are remote from a fan wheel, so that they absorb considerable heat and can transport it out of the interior of the pressure medium container.
Preferably, ribs running axially extend between an external wall of the electric motor and the inner external wall of the pressure medium container. The electric motor can abut the inner external wall of the pressure medium container by means of these ribs. At the same time, the ribs create a large heat loss area and the cooling air can flow between the ribs.
A compact hydraulic unit according to the invention can be manufactured in an especially simple and economical fashion where the inner external wall of the pressure medium container, the ribs, and the external wall of the electric motor are made in one piece. A portion of an extrusion-molded profile can then be used. In the vicinity of a fan wheel, the inner wall and the ribs of the extrusion-molded profile can be turned outward so that the cooling air can easily enter the flow channels between the ribs.
It is also favorable for the manufacture of the compact unit where an endwise flange, preferably every endwise flange, has an axial annular bead that internally centers the inner external wall and externally centers the outer external wall of the pressure medium container. The two end flanges as well as the external walls of the pressure medium container are advantageously held together by tie rods that extend through the pressure medium container. However, it is also possible for the tie rods to extend between the inner external wall of the pressure medium container and the electric motor or outside the pressure medium container.
A small number of individual parts and only a few sealing points are obtained if, one end flange of the pressure medium container is designed as a bottom in one piece with the outer external wall and with the inner external wall of the pressure medium container.
It is possible to secure the electric motor as far as its radial position relative to the pressure medium container is concerned by having it touch the inner external wall of the pressure medium container on the inside. However, the electric motor can also be
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patent: 5188516 (1993-02-01), Huang
Bock Herbert
Fassnacht Kurt
Hartmann Gunter
Kulawik Hubert
Farber Martin A.
Mannesmann Rexroth AG
Solis Erick
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