Pumps – Condition responsive control of drive transmission or pump... – Plural pumps with individual or relative control
Patent
1996-08-14
1999-06-22
Thorpe, Timothy S.
Pumps
Condition responsive control of drive transmission or pump...
Plural pumps with individual or relative control
4172221, 417287, 60428, 60443, 60445, F04B 4900
Patent
active
059136634
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for regulating the total power of at least two variable displacement hydrostatic pumps a device for total power regulation of at least two variable displacement hydrostatic pumps (1, 2) driven by a common drive motor (6). Each pump delivers into a working line (3), by adjustment of its displacement volume by setting devices (7-12), which are acted upon by a setting pressure and are biassed towards a maximum displacement volume. A regulation valve (18) is associated with each setting device, and each regulation valve is acted upon, against a counter-pressure, by a control pressure corresponding to a working pressure in the working line (3) of the variable displacement pump (1, 2), adjusted by the setting device (7-12). The regulation valve (18), in response to the control pressure being greater than the counter-pressure, regulates the pressure set by the setting devices (7-12) to reduce the displacement volume of the variable displacement pump (1, 2) to maintain constant the product of working pressure and displacement volume.
Such a device is known for example from DE-PS 42 08 925. The total power regulation of this known device distributes the total drive power made available from the drive motor between the two variable displacement pumps. It is based, as with any power regulator, on the principle of adjustment of the displacement volumes of the variable displacement pumps in dependence upon the working pressure such that the maximum drive torque in each case, or with constant drive speed of rotation, the maximum power take up of the variable displacement pumps in each case, remains substantially constant over the entire working range.
The working pressure generated by each variable displacement pump acts, with the known device, as control pressure on the respective associated regulation valve via a pressure piston and a lever arm of a double-armed pivot lever acted upon by this pressure piston. The pressure piston is displaceably arranged in the setting piston of the respectively associated setting device, constituted as a setting cylinder, and acts in such a manner on the lever arm that its lever length is so shortened upon displacement of the setting piston in the sense of a reduction of the displacement volume of the variable displacement pump that the working pressure can increase in the same ratio as the displacement volume of the variable displacement pump reduces. In this way, the product of working pressure and displacement volume is held constant.
The counter-pressure at each regulation valve is generated by two settable compression springs, of which one acts directly on the regulation valve and the other acts on the regulation valve via the lever arm of the pivot lever acted upon by the control pressure. A further control pressure, which corresponds to the working pressure generated by the respective other variable displacement pump, acts against the pressure of the compression spring acting upon the lever arm. The sum of the setting values of the two compression springs determines the maximum torque of the respective variable displacement pump concerned and corresponds to the total drive torque of the drive motor. This torque can be transmitted from each variable displacement pump so long as no second control pressure arises at the associated regulation valve, i.e. so long as the respective other variable displacement pump takes up no torque.
With increasing torque take-up of the latter variable displacement pump the counter-pressure at the regulation valve of the first variable displacement pump is reduced as a consequence of the corresponding increase of the further control pressure, and therewith the torque setting of the first variable displacement pump is reduced, down to a minimal value, which then occurs when the further control pressure is the same as or larger than the pressure of the compression spring acting on the lever arm. Therewith, the torque take-up of each variable displacement pump is restricted to a value (desired value of the individual d
REFERENCES:
patent: 4809504 (1989-03-01), Izumi et al.
patent: 4870819 (1989-10-01), Walzer
patent: 5176504 (1993-01-01), Moriya et al.
patent: 5182908 (1993-02-01), Devier et al.
patent: 5251440 (1993-10-01), Bong-dong et al.
patent: 5333997 (1994-08-01), Hormann et al.
patent: 5428958 (1995-07-01), Stenlund
patent: 5527156 (1996-06-01), Song
patent: 5554007 (1996-09-01), Watts
patent: 5575148 (1996-11-01), Hirata et al.
patent: 5576962 (1996-11-01), Ferguson et al.
patent: 5630317 (1997-05-01), Takamura et al.
Erkkilae Mikko
Fertig Gunter
Vogl Karl-Heinz
zu Hohenlohe Felix
Brueninghaus Hydromatik GmbH
Gartenberg Ehud
Thorpe Timothy S.
LandOfFree
Device for regulating the total power of at least two variable d does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for regulating the total power of at least two variable d, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for regulating the total power of at least two variable d will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1703608