Toothed-Lobed Gear Pump

Abstract

Toothed gears and lobed gears intermesh to create large volume pockets in gear sets of a given size. The pockets are larger than the pockets that exist in current tooth or lobe pumps and provide the benefit of a pump that better handles shear sensitive liquids. Preferably, the profiles of the teeth and of the lobes are involute-shaped to provide rolling contact and a fixed pressure angle between the teeth and lobes during engagement. The toothed gears and lobe gears improve upon standard spur and helical gear designs by omitting alternate teeth on the standard toothed gears and filling in corresponding gaps on the mating standard lobed gears. Additional tooth and lobed gear rotors may be added in tandem as additional pairs of gears to the shafts and circumferentially offset to provide driving tooth engagement between at least one pair of the toothed and lobed rotors at every point around the rotational circumference of the rotors. This spur gear or helical gear configuration eliminates the need for separate driving/synchronizing gears.

What is claimed is: 
     
         1 . A pump, comprising:
 a housing having an internal cavity that defines a pumping chamber, an inlet port adapted to allow a fluid into the pumping chamber, and an outlet port adapted to discharge the fluid from the pumping chamber; and   a gearbox located in the pumping chamber, said gearbox having a plurality of driving rotors including first and second toothed gears each having a plurality of teeth, said plurality of driving rotors also including first and second lobed gears each having a plurality of lobes wider than the teeth, said first toothed gear and said first lobed gear being a first gear set with said first toothed gear mounted to one of a first rotational axis and a second rotational axis in the pumping chamber adjacent the first rotational axis, and said first lobed gear mounted to the other one of the first rotational axis and the second rotational axis in the pumping chamber, said second toothed gear and said second lobed gear being a second gear set with said second toothed gear mounted to one of the first rotational axis and the second rotational axis in the pumping chamber, and said second lobed gear mounted to the other one of the first rotational axis and the second rotational axis in the pumping chamber, the first toothed gear intermeshed with the first lobed gear in a driving relationship therebetween, the second toothed gear intermeshed with the second lobed gear in a driving engagement therebetween, the teeth of the toothed gears and the lobes of the lobed gears having an involute shaped profile to provide continuously rolling contact and a fixed pressure angle between the teeth and lobes during the driving engagement, wherein one of the first rotational axis and the second rotational axis is a drive shaft.   
     
     
         2 . The pump of  claim 1 , each of the lobes having a first arcuate width, each of the teeth having a maximum arcuate width, the first arcuate width of each lobe being at least double the maximum arcuate width of each tooth. 
     
     
         3 . The pump of  claim 2 , wherein the first arcuate width of each lobe is at least thrice the maximum arcuate width of each tooth. 
     
     
         4 . The pump of  claim 1 , the second gear set being engaged in the driving relationship therebetween when the first gear set is disengaged between the first toothed gear and the first lobed gear. 
     
     
         5 . The pump of  claim 1 , the first gear set being engaged in the driving relationship therebetween when the second gear set is disengaged between the second toothed gear and the second lobed gear. 
     
     
         6 . The pump of  claim 1 , further comprising a partition wall extending orthogonally to the first and second rotational axes between the first gear set and the second gear set for hydraulically isolation of the fluid. 
     
     
         7 . The pump of  claim 1 , the teeth of said first toothed gear being angularly offset with relation to the teeth of said second toothed gear such that a tooth of said first toothed gear is axially aligned between two teeth of said second toothed gear. 
     
     
         8 . The pump of  claim 1 , said first toothed gear and said second lobed gear being mounted to the first rotational axis. 
     
     
         9 . The pump of  claim 1 , further comprising radial vanes extending from the teeth to seal circumferential liquid slip paths between the toothed gears and the housing and to seal slip paths between the toothed gears and the lobed gears. 
     
     
         10 . The pump of  claim 1 , further comprising radial vanes extending from the lobes to seal circumferential liquid slip paths between the lobed gears and the housing and to seal slip paths between the toothed gears and the lobed gears. 
     
     
         11 . A gearbox of a pump having a housing with an internal cavity that defines a pumping chamber, an inlet port adapted to allow a fluid into the pumping chamber, and an outlet port adapted to discharge the fluid from the pumping chamber, the gearbox located in the pumping chamber of the housing, said gearbox comprising a plurality of driving rotors including first and second toothed gears each having a plurality of teeth, said plurality of driving rotors also including first and second lobed gears each having a plurality of lobes wider than the teeth, said first toothed gear and said first lobed gear being a first gear set with said first toothed gear mounted to one of a first rotational axis and a second rotational axis in the pumping chamber adjacent the first rotational axis, and said first lobed gear mounted to the other one of the first rotational axis and the second rotational axis in the pumping chamber, said second toothed gear and said second lobed gear being a second gear set with said second toothed gear mounted to one of the first rotational axis and the second rotational axis in the pumping chamber, and said second lobed gear mounted to the other one of the first rotational axis and the second rotational axis in the pumping chamber, the first toothed gear intermeshed with the first lobed gear in a driving relationship therebetween, the second toothed gear intermeshed with the second lobed gear in a driving engagement therebetween, the teeth of the toothed gears and the lobes of the lobed gears having an involute shaped profile to provide continuously rolling contact and a fixed pressure angle between the teeth and lobes during the driving engagement, wherein one of the first rotational axis and the second rotational axis is a drive shaft. 
     
     
         12 . The gearbox of  claim 11 , each of the lobes having a first arcuate width, each of the teeth having a maximum arcuate width, the first arcuate width of each lobe being at least double the maximum arcuate width of each tooth. 
     
     
         13 . The gearbox of  claim 11 , the second gear set being engaged in the driving relationship therebetween when the first gear set is disengaged between the first toothed gear and the first lobed gear. 
     
     
         14 . The gearbox of  claim 11 , the first gear set being engaged in the driving relationship therebetween when the second gear set is disengaged between the second toothed gear and the second lobed gear. 
     
     
         15 . The gearbox of  claim 11 , further comprising a partition wall extending orthogonally to the first and second rotational axes between the first gear set and the second gear set for hydraulically isolation of the fluid. 
     
     
         16 . The gearbox of  claim 11 , the teeth of said first toothed gear being angularly offset with relation to the teeth of said second toothed gear such that a tooth of said first toothed gear is axially aligned between two teeth of said second toothed gear. 
     
     
         17 . The gearbox of  claim 11 , further comprising radial vanes extending from the teeth to seal circumferential liquid slip paths between the toothed gears and the housing and to seal slip paths between the toothed gears and the lobed gears. 
     
     
         18 . The gearbox of  claim 11 , further comprising radial vanes extending from the lobes to seal circumferential liquid slip paths between the lobed gears and the housing and to seal slip paths between the toothed gears and the lobed gears. 
     
     
         19 . The gearbox of  claim 11 , said first toothed gear and said second lobed gear being mounted to the first rotational axis. 
     
     
         20 . The gearbox of  claim 11 , wherein said toothed gears and said lobed gears are spur-shaped.