Pumps – Motor driven – Including means for facilitating assembly or disassembly of...
Utility Patent
1998-02-05
2001-01-02
Thorpe, Timothy S. (Department: 3746)
Pumps
Motor driven
Including means for facilitating assembly or disassembly of...
C417S415000
Utility Patent
active
06168393
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an electric motor/radial pump assembly which includes a base section that contains a radial piston pump together with its hydraulic connecting lines and control elements, an electric motor being operatively connected to the pump and being supported on one side of the base section coaxially with respect to the central axis of a pump output shaft, and a hydraulic tank being supported on the one side of the base section coaxial to that central axis.
Such assemblies have been known and are used with increasing frequency for transportable purposes or for generating small forces, for example, for the hydraulic activation of motor vehicle folding canopy tops, the movement of medical treatment chairs, tables, etc. Thus the main requirement is that the assembly be as small as possible which, with respect to operating cylinders and lines that must be manipulated, includes all relevant components in order that the construction and maintenance be as simple and efficient as possible.
A motor-driven radial piston pump assembly for hydraulic uses is disclosed in German document C3 32 27 926 in which the base section supports the pump and the hydraulic tank on one side and on the other side thereof the sealed, encapsulated motor for the pump is supported such that the remaining inner space in the motor housing is used as an oil tank via a connection opening in the base section. However, with such an arrangement, a relatively expensive so-called sub-oil motor is required such that the attachment of the assembly above the center of the supporting base section causes problems in many applications.
A radial piston pump assembly of the aforedescribed type is also disclosed in European published application A1 0 628 720 in which a cylindrical shaped tank for the hydraulic medium is coaxial with the base section and is secured directly thereto, and wherein the electric motor for operating the pump is coaxial with the tank and is secured directly thereto at a side opposite the side at which the tank is secured to the pump. The entry area of the motor shaft into the tank is sealed so that the motor itself is located outside and need not be specially constructed. However, this presents a disadvantage in that an elongated motor shaft for operating the pump must extend through the tank and that the tank is located between the motor and the base section and supports the motor such that the tank must be constructed of relatively stiff and heavy material.
OBJECT OF THE INVENTION
It is therefore an object of the present invention to provide an improved motor-driven radial piston pump assembly of generally the aforedescribed type in a manner that the noted disadvantages can be avoided while at the same time a compact construction is effected in a simple manner with a secure, and light weight mounting of the electric motor for the pump.
The motor-driven radial piston pump assembly according to the invention has its electric motor directly connected to the base section and includes a substantially cylindrical-shaped motor housing that surrounds the motor and is sealed and connected to the base section, the motor housing forming an inner wall of the hydraulic tank, and the housing being closed by a cover on an outer end thereof opposite the pump. With such an arrangement the base section bears the reaction forces and the weight of the motor and transmits those forces directly on the base section which also supports the pump, thereby effecting a very compact construction. The tank essentially surrounds the motor, which is maintained dry by the motor housing, for its entire length, so that a very compact construction results which in most cases is significantly lighter than the construction requirements set for the specific use of the assembly. There is no requirement for the additional expense of a sub-oil motor which would render the assembly unusable for those applications in which price plays a primary role. There is the added advantage of excellent noise insulation for the motor because it is surrounded by the cylindrical-shaped motor housing, the volume of the tank, and the outer covering forming the outer wall of the tank, so that applications are also possible in which such an assembly can now be used in those areas demanding additional sound insulation.
The base section of the assembly according to the invention serves as a pump receptacle for the pump together with its connecting lines and control elements, the base section including a pump support and a separate support flange secured to the electric motor, to the motor housing and to the hydraulic tank. Thus the essential components of the base section are divided according to function—the supporting elements for the motor and tank are combined in the support flange on which the pump support with the hydraulic components is placed on the outer side in relation to the tank and secured from the inside. Thus, if required, the support flange and the pump support can be of different materials such that simple replacement is possible. Also, the assembly can be constructed with pump supports for different pressures, different volumetric displacement and the like.
The motor housing according to the invention is connected to the base section and is sealingly secured to the outer periphery of a cylindrical-shaped projection of the support flange, the motor shaft passing through a central opening provided in such projection. This facilitates a simple construction which again makes possible, if needed, various materials to be used for the support flange and the cylindrical-shaped motor housing.
Further according to the invention the hydraulic suction line for the pump includes a suction pipe extending into the tank and a feeder line located in the pump support, the suction pipe being supported by the support flange so as to establish communication between the feeder line and the tank. The suction pipe can be constructed or positioned according to the actual attachment conditions of the assembly, so that the functioning of the hydraulic pump can be assured without changes required on the pump housing.
The cover for closing the one end of the motor housing may be formed integrally with the motor housing, or may be formed as a separate part.
A covering defines an outer wall of the hydraulic tank and supports the motor housing in surrounding sealed engagement therewith adjacent the cover which closes the outer end of the housing such that the covering can be of a one-piece construction resulting in a simple, leak-proof arrangement of the inner space of the motor housing for the electric motor.
The assembly may comprise an interference element and/or a temperature safeguard element for the electric motor located inside of the motor housing on a side opposite the base section. These elements can then be advantageously placed directly on or in the vicinity of the electric motor without forming any other obstacles.
The external covering is sealingly and removably connected to the support flange about an outer periphery thereof, such that the interior of the tank and the motor housing are easily accessible.
The motor housing can be of metal and the hydraulic tank cover of plastic materials. A metallic motor housing thus enhances improved heat transfer from the motor to the tank and provides improved EMV protection. The lighter plastic hydraulic tank covering provides a lighter and simpler construction, since the tank does not support other than its own weight and can also be simply sealed, as aforedescribed, against the cylindrical-shaped motor housing and thus supported on the side opposite the base section.
REFERENCES:
patent: 1983262 (1934-12-01), Zorzi
patent: 3719429 (1973-03-01), Rule
patent: 4416594 (1983-11-01), Ichikawa
patent: 4523899 (1985-06-01), Ouchi
patent: 4627793 (1986-12-01), Kuroyanagi et al.
patent: 4925373 (1990-05-01), Moate
Huber Gerhard
Schleich Gisela
Stolle Klaus
Gossett PLLC Dykema
Hoerbiger GmbH
Solak Timothy P.
Thorpe Timothy S.
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