US2434459A - Pumping mechanism - Google Patents

Description

Jan. 13, 1948.

J. Y. DAHLSTRAN D PUMPING MECHANISM Filed Nov. 20, 1943 Patented Jan. 13, 1948 UNITED STATES PATENT OFFICE 2,434,459 PUMPING MECHANISM Josef Y. Dahlsitrand, Indianapolis, Ind., assignor I to Universal Gear Corporation, Indianapolis, Ind., a corporation of Indiana Application November 20, 1943, Serial No. 511,140

Claims. (c1. 184-6) The present invention relates to pumping mechanisms and more particularly to oil pumps of the gear type adapted to be used in connection with high speed mechanisms such as steam or gas turbines, and to a novel means of connecting the pump to such prime movers to be driven thereby at a speed less than the rotational speed of the prime mover.

Gear pumps of the two shaft, straight spur gear type, such as embodied in this invention, have many uses in the delivery of fluids, especially oils employed in the pressure lubrication of machinery and as hydraulic fluids, since they operate at practically all pressures and capacities. Their utility is somewhat decreased however by their tendency to trap oil in the discharge side of the pump at the point of gear intermesh, which tendency increases with the rotational speed of the pump, resulting in noisy operation and low mechanical efliciency. This condition materially lowers the effectiveness of such pumps when used in connection with the above mentioned high speed turbine machinery.

Attempts have been made heretofore to reduce the effects of oil trapping by various means such as by providing discharge pockets in the side plates of the pump. These methods, however, while reducing the noise level of the pump, have not resulted in desired operating efllciency.

It is therefore one of the principal objects of this invention to provide means incorporated with a gear pump for reducing its rotational speed, thereby readily adapting such a pump for use with high speed mechanisms.

. Another object is to provide a means for coupling a gear pump to high speed machinery,

tion consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention may be varied in con- 'structlon, proportions and arrangements, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawing means for carrying the same into practical eilect without limiting the improvements in their useful applications to the particular construction which, for the purpose of explanation, have been made the subject of illustration.

In the drawing, Figure 1 represents a longitudinal sectional view of a gear pump with an incorporated reduction drive constructed in accordance with this invention, and Figure 2 is a cross sectional view taken along line 22 of Fig- 20.ure 1.

wise suitablysecured to a shaft 1, which is the drive shaft of the pump, while the gear 6 may be similarly secured to an idler shaft 8. One end of each of the shafts I and 8 is joumaled in bearings 9 and ID, respectively, supported in an end plate ll suitably attached to one iacepof which coupling means includes a reduction gear as a composite portion of the pump unit.

Still another object of this invention is to provide a composite pumping apparatus of the above character which incorporates means for introducing a portion of the oil being displaced by the pump for lubricating the gears in the speed reduction train. I

A further object is to provide a gear pump with an incorporated reduction gear drive and employing hollow shafts which also serve as conduits for delivering oil from the pump to points of use.

A still further object is to provide a pump having the above characteristics in which power take-off means are provided for operating a tachometer or other desired apparatus.

the casting 3. The opposite ends of the shafts 1 and 8 are respectively ournaled i bearings I 2 and I3 supported in an end plate l4 secured to the opposite face of the castin ii. The plate I4 40 serves also as a partition wall bet een the pump case 2 and the reduction gear case/3;

'The gear,case 2 comprises a cup-shaped casting E5, the open edge of which is secured by means, not shown, to the outer, face of the end plate It andis provided with a discharge duct [6 With these and other objects in/ view, which may be incident to my improvements, the invencommunicating with its interior.

The casting l5 has therein a socket 11 in axial alignment with the shaft I and which is fitted with a bearing member l8 in which the free end of the shaft 1 is journaled. The casting i5 is also bored, as indicated at l9, and fitted with a bearing 20 for journaling one end of a countershaft 2|, the opposite end of which is journaled in a bushing 22 concentrically fitted into one 56 end of the shaft 8. The opposite end of the shaft 3 2| is provided with means such as slots 2| for coupling the shaft to a rotating shaft 8 of a prime mover M which, for example. may be the high speed steam or gas turbine above referred to.

A flanged cylindrical extension 23 is formed on the casting I5, concentric with the extension of the shaft 2|, and serves as a convenient means for attaching the pump unit to the above mentioned prime mover.

As above set forth, straight spur gear pumps operate at highest mechanical efliciency at substantially low speeds. In order to reduce the rotative speed of the pump when coupled to high speed machinery, a speed reduction coupling is provided between the drive shaft 2| and the gear pump. While other types of speed reduction mechanisms may be used, I prefer to employ compound gearing, an efficient arrangement of which is as follows.

A large gear 24 is keyed or otherwise secured to the shaft 1. This gear 24 meshes with the small gear 25 of a compound idler gear 26, mounted for free rotation on the shaft 2|, the large gear 21 of which meshes with the small gear 28 of a second compound idler gear 28 mounted for free rotation on the shaft 1. The large gear 30 of the compound gear 28 meshes with a pinion 3| formed on the drive shaft 2|. The idler gears 25 and 28 may each be provided with an antifriction bushing such as shown at 32 and 33.

It will be noted that this reduction train of gears is contained within the gear case l5.

In order to provide a practical and efficient means for lubricating the reduction gear train, the shaft 1 is drilled axially from the end thereof carrying the gears 24 and 28 to form a passageway 34 which communicates with a radial passage 35 aligned with a radial oil hole 36 in the gear 5. Radial passages 31 and 38 are'likewise provided in the shaft 1 to connect the duct 34 respectively with peripheral grooves 38 and 48 formed on the outer surface of the shaft 1 adjacent each of the gears 28 and 30 of the com,- pound idler unit 29. Gears 28 and 30 are respectively bored radially from their outer peripheries through the bushings 33 to communicate with these peripheral grooves as shown at 4| and 42. If desired, a passageway 43 may likewise be drilled from the outer periphery of the gear 24 through the wall of the hollow shaft 1 to also communicate with the bore 34.

From the above, it will be seen that when the pump is in operation a small amount of the oil carried around by the gear 5 will find its way through the passages 36 and 35 and into the axial bore 34 of the shaft 1. This oil will then flow through the duct 43 to lubricate the mating teeth of the gears 24 and 25. The oil will also flow through the ducts 31 and 38 into the peripheral grooves39 and 48, thence through the radial passageways 4| and 42, to lubricate the bearing surface between the bushing 33 and the shaft 1 to lubricate the mating teeth respectively of the gears 28 and 21, and the gears 30 and 3|. Oil discharged through the ducts in the manner above described will be collected in the gear case 3 from which it may be discharged through the discharge passageway i6. This discharge duct IE, if desired, may be connected with the input side of the pump to return this oil into the oil flow circuit. The oil entering the passageway 34 is onlya portion of the oil carried through the pump chamber between two adjacent teeth of the gears 5 and 6, and while suflicient to effec- 4 tively lubricate the bearings and teeth or the reduction gearing, is not enough to materially affect the output of the pump.

A cover plate 44 is provided for the outer face of the end plate II and is secured thereto by suitable means such as cap screws 45. The cover plate 44 is provided with a hollow boss 48 into which projects a reduced extension 41 of the shaft 1, which extension may be iournaled in a bearing 48 carried by the end plate 44 in axial alignment with the shaft I. Extension 41 may be slotted, as indicated at 48, to thereby provide a power take-off means from the pump unit to which may be coupled any desired driven apparatus as, for example, a tachometer (not shown).

It will be noted that the end of the shaft 8 adjacent the end plate 44 does not extend entirely to the outer surface of the end plate II and thereby provides a-pocket 50 between the end of the shaft 8 and the plate 44, and the cover late 44 is provided with a threaded aperture 5| which communicates with this pocket.

In certain types of machines, oil, to lubricate and cool their bearings is conducted through drilled shafting of the machine. When the oil pump is coupled directly to such a shaft I have found it expedient, since the pump housing I is attached to the machines, to conduct the oil to these bearings directly through the pump unit.

To accomplish this, the shafts 8 and 2| are each longitudinally bored as indicated at 52 and 53 to provide a continuous passageway through these shafts, which, when the shaft 2| is-coupled to the shaft of the machine, is adapted to communicate with the usual oil duct supply in the bearings of the prime mover. 011 from the input side 55 of the pump is delivered by the gears 5 and 8 into the passages 52 and 53 through a pipe 54 communicating with the output side 51 of the oil pump and connected with the pocket 50 by means of a coupling 55 fitted into the aperture 5|.

The oil flowing through the bores 52 and 53 may also be utilized to lubricate parts of the reduction gear not reached by the oil discharge from the bore 34 in the shaft 1, in this case the bearing of the compound idler 25. Radial ducts such as indicated at 58 are provided through the cylindrical wall of the shaft 2| adjacent the compound gear 25 and a portion of the oil flowing in the passage 53 will flow through these ducts to lubricate the bearing 32 or this gear.

In operation, when the pump unit is connected with a prime mover by coupling the shaft 2| to the rotating shaft of the prime mover, as above set forth, rotation will be imparted to the pump gears 5 and 6 at reduced speed through the train of gears 3|, 30, 28, 21, 25 and 24. This train of gears constitutes a three-stage reduction and while such a gear ratio is shown for purposes of illustration, obviously any suitable reduction ratio and arrangement of gearing may be employed to adapt the pump to any desired rotational speed. During the operation, lubricating oil is delivered directly from the pump in controlled amounts to lubricate both the bearings and teeth of the gears in the reduction train.

Thus it will be seen that I have devised a gear pump unit which may be easily coupled with high speed machinery to be used in connection therewith and driven thereby at a speed whereby the pump operates at highest efllciency.

While I have shown and described the preferred embodiment of my invention, I wish it to amuse be understood that I do not confine myself. to the precise details of construction herein set forth by way of illustration, as it is apparent that many changes and variations/may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim:

1. In combination, a rotary mechanism of the type having a normal operating speed in excess of efficient operating speeds of gear pumps, a casing enclosing a pump chamber and a gear case, saidmhamber having an oil inlet and an oil outlet, a pair of intermeshing spur gears in said chamber and constituting therewith a positive displacement pump, a shaft for one of the gears extending into the gear case, a second shaft operatively connected with said rotary mechanism, reduction gearing in said gear case connecting the first and second shafts for imparting rotation of the second to the first at reduced speed, an axial passageway in the second shaft, and conduit means including said passageway connecting the oil outlet with said rotary mechanism.

2. In combination, a rotary mechanism of the type having a normal operating speed in excess of efiicient operating speeds of gear pumps, a casing enclosing a pump chamber and a gear case, said chamber having an oil inlet and an oil outlet, a pair of intermeshing spur gears in said chamber and constituting therewith a positive displacement pump, a shaft for one of the gears extending into the gear case, a second shaft operatively connected with said rotary mechanism. reduction gearing in said gear case connecting the first and second shafts for imparting rotation of the second to the first at reduced speed. an axial passageway in the second shaft, conduit means includ ng said passageway connecting the oil outlet with said rotary mechanism, a passageway in the first named shaft communicating with said pump chamber to receive oil therefrom, and duct means communicating with the second named passageway for conducting oil therefrom to parts of said reduction gearing to be lubricated.

3. In combination, a rotary mechanism of the type having a normal operating speed in excess of eificient operating speeds of gear pumps, a casing enclosing a pump chamber and a gear case, said chamber having an oil 'inlet and an oil outlet, a pair of intermeshing spur gears in said chamber and constituting therewith a positive displacement pump, a shaft for one of the gears extending into the gear case, a second shaft operatively connected with said rotary mechanism, reduction gearing in said gear case connecting the first and second shafts for imparting rotation of the second to the first at reduced speed, an axial passageway in the second shaft, conduit means including'said passageway connecting the oil outlet with said rotary mechanism, a passageway in the first named shaft communicating with said pump chamber to receive oil therefrom, duct means communicating with the second named passageway for conducting oil therefrom to parts of said reduction gearing to be lubricated, and other duct means communicating with the first passageway for conducting oil therefrom to other parts of said reduction gearing to be lubricated.

4. Oil pumping apparatus comprising a casing enclosing a pump chamber and a gear case, said pump chamber having an inlet and an outlet, a pair of intermeshing spur gears in the pump chamber and constituting therewith a positive displacement pump, a shaft for one of said gears journalled in the casing, a drive shaft journalled in the casing and projecting therefrom, a reduction gear train in said gear case operatively connecting said drive shaft and shaft for the spur gear for imparting rotation of the drive shaft to the shaft for the spur gear at reduced speed, an axial passageway extending through the drive shaft and communicating with said outlet and constituting the main discharge conduit for the pump, a passageway in the shaft for the spur gear communicating with the pump chamber for conducting a small amount of oil therefrom, and duct means communicating with the second named passageway for conducting oil therefrom to points to be lubricated in said gear train.

5. Oil pumping apparatus comprising a casing enclosing a pump chamber and a gear case, said pump chamber having an inlet and an outlet, 8. pair of intermeshing spur gears in the pump chamber and constituting therewith a positive displacement pump, a shaft for one of said gears iournalled in the casing, a drive shaft journalled in the casingand projecting therefrom, a reduction gear train in said gear case operatively connecting said drive shaft and shaft for the spur gear for imparting rotation of the drive shaft to the shaft for the spur gear at reduced speed, a shaft for the other spur gear in axial alignment with the drive shaft, an axial passageway extending through said aligned shafts. conduit means communicating with said outlet and including said passageway constituting the main dischargeconduit for the pump, a passageway in the first named shaft communicating with the pump chamher for conducting a small amount of oil therefrom, and duct means communicating with the last named passageway for conducting oil therefrom to points to be lubricated in said gear train.

JOSEF Y. DAHLSTRAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,176,936 Waldon Mar. 28. 1916 1,362,621 Hawley Dec. 21, 1920 1,550,099 Sayre Aug. 18, 1925 1,686,839 7 Rhoads Oct. 9. 1928 1,991,341 Aycock Feb, 12, 1929 FOREIGN PATENTS Number Country Date 259,222 Great Britain Nov. 25, 1926 305,016 Great Britain Aug. 22, 1929 353,273 Great Britain July 23, 1931

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