Expansible chamber devices – Piston – With separable means for pivotally mounting connecting rod...
Patent
1996-12-23
1998-06-02
Denion, Thomas E.
Expansible chamber devices
Piston
With separable means for pivotally mounting connecting rod...
92 71, 92248, 417269, 74 60, 403130, F16J 114
Patent
active
057585660
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a piston with a slide shoe for a hydraulic piston engine, where the piston is designed with a ball socket, and where the slide shoe is provided with a corresponding ball head, whereby these are connected in a ball-and-socket joint.
Hydraulic piston engines with such pistons with slide shoes may function for example according to the axial piston or radial piston principle. In both cases are the pistons placed slidingly in a cylinder block, and the slide shoe is held in contact against a guide surface in such a manner that the piston is moved in the cylinder block as a result of a relative movement of the cylinder block in relation to the guide surface, whereby the slide shoe slides across the guide surface.
In order to reduce friction between among other things the piston and the slide shoe, several constructions are known where one of the contact surfaces in the ball-and-socket joint connecting the piston and the slide shoe is made at least partially of a friction-reducing material.
WO Patent Application No. DK 93/00443, now U.S. Pat. No. 5,601,009, describes a piston for a hydraulic piston engine with a slide shoe where the slide shoe is provided with a ball head, which is moulded into a layer of friction-reducing material, and where the piston is provided with a corresponding ball socket, forming a ball-and-socket joint between the piston and the friction-reducing material on the slide shoe.
According to WO Patent Application No. DK 93/00443, the friction-reducing coating may be moulded into the void established between the ball head and the ball socket when the ball head is inserted in the ball socket, for example in a plastic injection moulding tool. In this manner it is achieved in particular that the ball-and-socket joint is installed in a simple manner in the injection moulding process, and that separate installation parts are not required. As a consequence of the thermal shrinking of the moulded-on material, a gap is formed between the friction-reducing material on the ball head and the ball socket on the piston.
The present invention is based on the technology according to WO Patent Application No. DK 93/00443 and is a further development of same.
SUMMARY OF THE INVENTION
The invention is particular in that the material moulded on the slide shoe, which forms the ball head, is of uneven thickness.
Among other things, this leads to a better fixation of the ball head on the slide shoe than is possible by the technology according to WO Patent Application No. DK 93/00443, because the moulded-on material cannot slip on the ball head of the slide shoe, as it may happen in the case of the technology according to WO Patent Application No. DK 93/00443.
In addition, it is often advantageous when piston engines are concerned that there is a gap of some size between the plastic coated surface of the slide shoe and the surface of the ball socket of the piston. In certain situations gap sizes are required which are not immediately obtainable by the process according to WO Patent Application No. DK 93/00443, among other things because the shrinkage properties of the friction reducing material may be limiting to the gap size, depending on the space between the ball head and the ball socket.
According to this invention, the ball head of the slide shoe may be made exclusively from friction reducing material or it may be provided with a support element which protrudes into the ball head, and where in relation to a spherical surface the support element has an irregular shape in relation to a spherical surface.
A particularly low-cost embodiment of the invention is described, where the whole slide shoe is made of a friction-reducing material.
The slide shoe may be a solid construction, or there may be a lubricant or refrigerant duct in the slide shoe and in the piston with a view to providing lubricant or refrigerant to, among other things, the sliding surface of the slide shoe against the guide surface.
By enclosing the support element completely by the
REFERENCES:
patent: 3125004 (1964-03-01), White
patent: 3221564 (1965-12-01), Raymond
patent: 3455585 (1969-07-01), Raymond
patent: 5013219 (1991-05-01), Hicks et al.
patent: 5392693 (1995-02-01), Engel et al.
patent: 5469776 (1995-11-01), Martensen et al.
patent: 5490446 (1996-02-01), Engel
patent: 5601009 (1997-02-01), Jepsen et al.
Jepsen Hardy Peter
M.o slashed.ller Henry Madsen
Danfoss A/S
Denion Thomas E.
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