Positive displacement pump apparatus and method
View Patent ↗An improved positive displacement rotary pump apparatus and method is provided. The pump may include a front cover, a rotor body forming a chamber with the front cover, a gear case supporting a pair of hollow drive shafts, and a pair of rotors disposed in the chambers and each detachably mounted to one end of a respective hollow drive shaft via a stud that extends from the rotor through the hollow shaft to a fastener.
1. A pump, comprising:
a front cover;
a pump body forming a chamber with the front cover;
a pair of hollow drive shafts, each drive shaft having a first end and a second end;
a gear case supporting the pair of hollow drive shafts;
a pair of mounting studs;
a pair of fasteners;
a pair of rotors disposed in the chamber and each detachably mounted to the first end of a respective hollow drive shaft via a respective mounting stud that extends from the rotor through the respective hollow drive shaft to a respective fastener at the second end of the hollow drive shaft; and
an oil pump to circulate oil or other lubricant inside the gear case,
wherein the oil pump is a reciprocating pump driven by a cam disposed on one of the drive shafts.
2. A pump according to claim 1 , wherein each drive shaft and each rotor engage with each other via a spline connection.
3. A pump according to claim 2 , wherein each stud is directly attached to each rotor proximate the axial location of the splines.
4. A pump according to claim 3 , wherein each mounting stud extends outward past the respective drive shaft at the second end of a drive shaft opposite the rotor, and wherein the fasteners are each engagable with the extending part of each mounting stud to axially fix the position of the stud relative to the position of the respective drive shaft.
5. A pump according to claim 4 , wherein the extending part of each stud is threaded and wherein each fastener is a nut that also contacts the second end of the drive shaft.
6. A pump according to claim 1 , wherein each stud has an outer diameter that is smaller than an inner diameter of each hollow shaft.
7. A pump, comprising:
a front cover;
a pair of drive shafts;
a pump body forming a chamber with the front cover;
a gear case supporting the hollow drive shafts;
a pair of rotors disposed in the chambers, wherein each rotor is driven by a respective drive shaft and each drive shaft is mounted to the gear case by a pair of bearings that rotatably support the shaft in the gear case, with each bearing being located relative to the gear case by a respective locating ring that is axially movable relative to the gear case, so that each bearing is axially adjustable relative to the gear case; and
an oil pump to circulate oil or other lubricant inside the gear case,
wherein the oil pump is a reciprocating oil pump driven by a cam on one of the drive shafts.
8. A pump according to claim 7 , wherein axial adjustment of both bearings of a respective drive shaft in one direction moves the drive shaft in that direction.
9. A pump according to claim 8 , wherein for each drive shaft, the first bearing retainer is located axially outside of the first bearing, and the second bearing retainer is located axially outside the second bearing, so that the bearings are both trapped between the bearing retainers.
10. A pump according to claim 9 , wherein the bearings each contact a respective shoulder located on the drive shaft, in between the bearings, so that tightening of both bearing retainers urges the bearings axially inward to abut their respective shoulder.
11. A pump according to claim 7 , wherein each locating ring comprises an externally threaded ring residing in an internally threaded bore of the gear case.
12. A pump according to claim 7 , wherein axial adjustment of both bearings of a respective drive shaft in one direction moves the drive shaft in that direction.
13. A pump according to claim 7 , wherein each locating ring comprises an externally threaded ring residing in an internally threaded bore of the gear case.
14. A pump according to claim 13 , further comprising a respective set screw for locking the position of each bearing retainer.
15. A pump according to claim 7 , wherein the first bearing retainer is located axially outside of the first bearing, and a second bearing retainer is located axially outside the second bearing, so that the bearings are trapped between the bearing retainers.
16. A pump according to claim 7 , wherein the bearings each contact a respective shoulder located on the drive shaft, in between the bearings, so that tightening of both bearing retainers urges the bearings axially inward to abut their respective shoulder, thereby adjusting the internal clearance of each bearing.
17. A pump, comprising:
a front cover;
a pair of drive shafts;
a pump body forming a chamber with the front cover;
a gear case supporting the hollow drive shafts;
a pair of rotors disposed in the chambers, wherein each rotor is driven by a respective drive shaft and each drive shaft is mounted to the gear case by a pair of tapered bearings to rotatably support the shaft in the gear case, with each bearing being located relative to the gear case by a respective locating ring that is axially movable relative to the gear case, so that an internal clearance of each bearing is adjustable by adjusting the distance between the locating rings, and
an oil pump to circulate oil or other lubricant inside the gear case,
wherein the oil pump is a reciprocating oil pump driven by a cam on one of the drive shafts.