Rotary expansible chamber devices – Positively actuated vane – Fluid biased
Patent
1994-07-27
1995-11-14
Bertsch, Richard A.
Rotary expansible chamber devices
Positively actuated vane
Fluid biased
418 15, 137514, 1375124, 137856, F04C 200
Patent
active
054661358
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention concerns a vane-cell pump having a cam ring supported in the housing where a rotor fastened to a shaft rotates with vanes radially movable in slots. Between the vanes are working chambers closed by lateral front plates. One of the front plates has suction and pressure zones for feeding and removing oil. A valve device is situated in one of the front plates which prevents a reflux of oil already delivered when the working chambers are partially filled.
BACKGROUND OF THE INVENTION
A vane-cell pump having the features mentioned has already been disclosed in DE 41 10 734 A1. In this pump, the rotor has a bore system consisting of a number of interconnected radial and axial bores attached to the working chambers. The axial bores of said bore system are covered by an outlet valve designed as a check disc. The check disc, coordinated with all of the working chambers, prevents previously pressurized oil from flowing back into the partly filled working chambers. It is possible, in this manner, to prevent damage caused by cavitation. The already known vane-cell pump works with the advantage of so-called suction control, that is, the pump sucks only the amount of oil needed at the time. Accordingly, an excessive amount of oil is not pressurized which is subsequently sent back to the suction zone via a flow-control valve. Input can be saved in this manner. The check disc, closing the axial bores in the rotor, is compressed by a pressure element supported in one front plate, generating undesired friction between the rotor and the check disc. Because of the radial and axial bores passing into each other at right angles, the pump has, in addition, relatively high inner drag.
The problem on which the invention is based is to find a suction-controlled vane-cell pump as free of erosion as possible and having low inner drag and smooth operation. Another requirement is to accommodate the parts required for suction control of the pump in a narrow space so that the body of the pump can be built small and yet capable of reaching a high reliability of operation.
SUMMARY OF THE INVENTION
According to the main feature, the rotor has control slots between the vanes which, in the area of the pressure zone, cooperate with several outlets arranged in tandem in the front plate. The valve device is fastened on the rear side of the front plate and controls the outlets. The control slots are dimensioned, in relation to the outlets, in a manner such that no reflux of delivered oil from a working chamber of higher pressure into a working chamber of lower pressure can occur. The valve device ensures that the oil present in the constantly narrowing working chambers be prestressed and ejected only when the oil volume corresponds to the existing size of the chamber. The above mentioned features provide a suction-controlled pump of low running noise where cavitation damage can be reliably prevented.
According to one feature, the valve device is designed as a tongued valve wherein a supporting body fastened on the front plate limits the opening stroke of the front plate. The supporting body simultaneously serves to fix the valve. The valve is designed as one piece for both pressure zones, the tongues lying homologously with respect to each other. The valve device consists of only two separate parts which can be quickly assembled. It is also advantageous, for smooth running, if the supporting body has oil pockets, in the area of the tongues, for damping the opening stroke.
According to another feature, the diametrically opposite suction zones are each connected with an annular suction chamber via a respective throttle bore. Said throttle bores limit the flow of sucked oil so that a further increase of the flow rate, above a specific speed of the pump, can not take place. The annular suction chamber connected with the suction zones can, in one embodiment, communicate with a suction connection, but also with only one throttle bore.
In another feature, the pressure-conveying outlets discharge behind the valv
REFERENCES:
patent: 1913758 (1933-06-01), Hapkins
patent: 2771860 (1956-11-01), Falk
patent: 3054357 (1962-09-01), McGill
patent: 3939867 (1976-02-01), Lundvik et al.
patent: 4516918 (1985-05-01), Drutchas et al.
patent: 4913636 (1990-04-01), Niemiec
Draskovits Gunter
Merz Johann
Bertsch Richard A.
Freay Charles G.
ZF Friedrichshafen AG
LandOfFree
Rotary vane-cell pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotary vane-cell pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotary vane-cell pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1217068