Motors: expansible chamber type – Three or more cylinders arranged in parallel radial or...
Patent
1995-10-02
1997-08-19
Freay, Charles G.
Motors: expansible chamber type
Three or more cylinders arranged in parallel radial or...
91492, 92182, F01B 1304
Patent
active
056576811
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a hydraulic drive system for operating primarily heavy industrial units of large dimensions, such as rotating mills, furnaces, drums, winches and the like or linearly moving conveyors, cranes, hoists and the like, comprising a plurality of hydraulically driven piston units with cam rollers, which are disposed to act against a wave-shaped cam profile of a cam curve element so that linear movement of the cam rollers against the cam profile produces a relative drive movement between the cam curve element and the piston units.
BACKGROUND OF THE INVENTION
Hydraulic rotational motors of cam ring type are previously known, comprising a fixed hub-like cylinder housing with a number of peripherally spaced radially oriented cylinders, in which cam roller supporting pistons, usually working diametrically in pairs, act with their radially guided cam rollers against a radially inwardly facing wave-shaped cam curve of a ring element surrounding the cylinder housing. As the piston moves outwards, the rollers are pressed against the cam curve and force it to rotate by virtue of the tangential force created. Characteristic of such hydraulic motors is that they can generate a very high constant torque over the entire rpm range from standing still up to maximum rpm. This type of hydraulic motor therefore has very good starting and low rpm performance without requiring any gears, at the same time as its design is relatively compact, simple and easy to service with the possibility of stepless rotational speed control.
By virtue of these advantageous features, hydraulic motors of cam ring type have found wide-spread application in the operation of relatively heavy industrial units, viz as motors for winches, apron conveyors, mills, drying drums and the like.
For operating units with very large dimensions, such as ore mills, drying ovens, barking drums and the like, today's hydraulic motors of cam ring type have, however, certain limitations.
SUMMARY OF THE INVENTION
A primary purpose of the present invention is to provide a hydraulic drive system operating according to the above described cam curve principle, which can be applied to operating units with very large external dimensions.
In its broadest concept, this purpose is achieved according to the present invention by virtue of the fact that the drive system is constructed of separate, assembled modules of cam curve elements and separate, assembled piston units, said modules of cam curve elements being mounted on the operating unit which is to be driven, and the piston units are mounted on a fixed frame, or vice versa. The proposed principle makes it possible to assemble components delivered as kit modules for the drive system of very large units.
A hydraulic motor of this type for rotation, can thus be used for very large operating units, such as mills or furnaces, the modules of the cam curve element having the shape of curved segments which are assembled into a ring or at least a portion of a ring around the periphery of the unit with the cam profile of the cam curve segments facing radially outwards, while the piston units are mounted in the frame along a circular arc radially outside the assembled curved cam curve segments.
The hydraulic drive system according to the invention can also be applied to linear driving of large work units, for transporting cranes, driving conveyors or the vertical driving of lifting means and jacks, with the modules of cam curve elements being straight and the piston units being mounted along a straight line parallel to the cam curve element.
In principle there is no upper limit as to how large the hydraulic drive system according to the invention can be made.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the drive system according to the invention will be described in more detail below with reference to the accompanying drawings, where:
FIG. 1 shows an end view of a drum rotating about a horizontal axis, driven by a hydraulic drive system according to the invention, wh
REFERENCES:
patent: 3439551 (1969-04-01), Militana
patent: 3511131 (1970-05-01), Kress
patent: 4066002 (1978-01-01), Eastman
patent: 4503751 (1985-03-01), Pinson
patent: 5101925 (1992-04-01), Walker
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