Patent Application
20140301882
This invention is directed to a multiple section hydraulic gear pump, and more particularly to a hydraulic gear pump capable of providing up to four different flow rates.
There exists a need in the art for a hydraulic pump that has multiple output flows to accommodate various machine functions that are combined with finite machine elements. There also is a need for a pump that minimizes engine HP requirements during all phases of machine operation. Finally, there is a need for a pump that is adjustable to allow reduced starting torsional loads during extreme cold engine start conditions.
Therefore, an objective of the present invention is to provide a hydraulic pump that is easily adjustable to provide multiple output flows during all phases of machine operation.
These and other objectives will be apparent to one of ordinary skill in the art based upon the following written description, drawings and claims.
A selective flow hydraulic gear pump has an integral unit with a front pump section and a rear pump section. The front pump section has a pumping gear set contained within a gear plate associated with, and adjacent to a bearing plate housing. The rear pump section has a pumping gear set contained within a gear plate associated with, and adjacent to a cover housing.
The integral unit has an inlet port common to both the bearing plate housing and the cover housing. Check valves and solenoid operated control valves are contained within the bearing plate housing and the cover housing and are associated with a first fluid conduit. A second fluid conduit is in communication with and extends between the bearing plate housing and an outlet port for the cover housing.
Referring to the Figures, a hydraulic gear pump 10 has, within a total number of pumping sections, an integral unit 12 having a pair of pumping gear sets 14 and 16 consisting of gears 18 and 20 contained within gear plates 22 and 24. The gear sets 14 and 16 are of any displacement available, but will necessarily be of differing displacements to allow medium and low pump flow options, and have a bearing plate housing 26 that separates the gear sets 14 and 16 of the integral unit 12 into a front, or first gear set 14, and a second or rear gear set 16. Gear sets 14 and 16 may be positioned such that gear set 14 is in the front pumping section and gear set 16 is in the rear pumping section, or the great set 16 is in the front pumping section and gear set 14 is in the rear pumping section. For illustrative purposes, however, gear set 14 will be shown as the larger gear set and gear set 16 will be shown as the smaller gear set.
Referring to the integral unit 12 without regard to other pump sections that may exist within the hydraulic gear pump 10, either the bearing plate housing 26, the cover housing 28, or both have an inlet port 30 common to both the front 14 and rear 16 pump sections. Both the bearing plate housing 26 and cover housing 28 have a check valve 32 and a solenoid operated control valve 34 associated with a fluid conduit 36. The check valves 32 and solenoid operated control valve 34 are of any size, shape, and type. The check valve 32 in the bearing plate housing 26 prevents flow from the rear pump section 16 to the front pump section 14. The check valve 32 in the cover housing 28 prevents flow from the front pump section 14 to the rear pump section 16.
External to the gear sets 14 and 16 is a passage or conduit 38 that is in communication with and extends from the front pump section 14 bearing plate housing 26 to a hydraulic outlet port 40 in the cover housing 28.
In operation, to generate high flow, both solenoid operated control valves 34 are caused to close which causes output flows from the front pump section 14 and the rear pump section 16 to combine at the hydraulic outlet port 40.
To generate a medium flow, with the larger displacement gear set 14 in the rear, the solenoid valve 34 in the bearing plate housing 26 is caused to open so that the flow of the smaller front pump section 16 is rerouted back to the pump inlet 30 at low pressure while flow from the rear pump section 14 is routed to the outlet port 40.
To generate medium flow, with the larger displacement gear set 14 in the front, the solenoid valve 34 in the cover housing 28 is caused to open so that the flow in the smaller rear pump section 16 is rerouted back to the pump inlet 30 at low pressure while flow from the front pump section 14 is routed to the outlet port 40.
To generate low flow, with the larger displacement gear set 14 in the rear, the solenoid valve 34 in the bearing plate housing 26 is caused to close while the solenoid valve 34 in the rear pump section cover housing 28 is opened. As a result, flow from the rear pump section 14 is re-routed back to the pump inlet 30 and flow from the smaller front pump section 16 is routed to the outlet port 40.
To generate low flow, with the larger displacement gear set 14 in the front, the solenoid valve 34 in the bearing plate housing 26 is caused to open while the solenoid valve 34 in the rear pump section cover housing 28 is closed. As a result, flow from the front pump section 14 is re-routed back to the pump inlet 30 and flow from the smaller rear pump section 16 is routed to the outlet port 40.
Finally, to generate zero flow, both solenoid valves 34 are caused to be opened such that flows from both the front pump section 36 and the rear pump section 34 are rerouted to pump inlet 30 and no flow is routed to the outlet port 40.
Thus, a selectable flow hydraulic pump has been disclosed that at the very least meets all the stated objectives.
This application claims the benefit of U.S. Provisional Application No. 61/809,663 filed Apr. 8, 2013.
| Number | Date | Country | |
|---|---|---|---|
| 61809663 | Apr 2013 | US |
