US2853952A

US2853952A - Gear ring bushing

Info

Publication number: US2853952A
Application number: US544738A
Authority: US
Inventors: Leslie L Aspelin
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1955-11-03
Filing date: 1955-11-03
Publication date: 1958-09-30
Anticipated expiration: 1975-09-30

Description

P 30, 1958 L. L. ASPELIN 2,

GEAR RING BUSHING Filed Nov. 3, 1955 Les/Le L. Aspe/Ln United States Patent C GEAR RING BUSHING Leslie L. Aspelin, Cleveland Heights, Ohio, assignor to Thompson Products, Inc Cleveland, Ohio, a corporation of hio' Application November 3, 1955, Serial No. 544,738

7 Claims. (Cl. 103126).

gear pump vary as a function of the rotational speed of i the pump and as a function of the discharge pressure. Accordingly, with a pressure loaded gear pump of the type using pressure loaded movable end plate means, the total force tending to separate. the mating gear and end plate and the line of action of. that forcetends to change with the speed of rotation of the gear impeller. To provide a loading force acting. on the movable end plate which will be equal and opposite to a. varying load, it would be necessary to change not only the quantitative value of the loading force, but it would also be necessary toapply such force at different locations.

According to the principles of the present invention,- these objectives are satisfied by the provision of a gear pump bearing, end plate means having an irregularly shaped back surface or non-friction surface which forms together with means including a portion. of the housing of the pump a plurality of circumferentially spaced localized confined pressure control chambers. ber communicates with the friction side of the end plate means at a point axially opposite the corresponding pressure control chamber, thereby to progressively vary the quantitative value of pressure force in the circumferentially spaced pressure control chambers and. thereby varying the amount of thrust acting upon. the end plate means from the inlet to the outlet.

Furthermore, it is contemplated according to the present invention to vary the effective motive surfaces of each respective pressure control chamber in such a. manner. that. the loading force acting on the end plate means varies from a minimum on the inlet side of the pump to a maximum at the outlet side of the pump.

It is an objectof the present invention, therefore, to provide an improved pressure loaded gear pump.

Another object of the present invention is to provide a loading force on movable end plate means for a pump which will be equal and opposite to a varying load developed in the pumping cavity.

Yet another object of the present invention is to provide a pump in which end plate means are subjected to different quantitative values of loading force and in. which the loading force is, in effect, applied at different locations depending upon the operating conditions existing within the pump.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheet of drawing in which a preferred structural embodiment of a pressure loaded gear pump incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

Each. cham- Figure 1 is-a cross'sectional view of a pressure loaded gear pump incorporating a bearing end plate means provided in-accordance with the principles of the present invention;

Figure 2 is a cross sectional view reduced in size and fragmentary in part taken substantially on line IIlI of Figure l;

Figure 3' is an elevational view of a bearing end plate means provided in accordance with the principles of the present invention;

Figure 4 is an end elevational view of the bearing end plate means of Figure 3;

Figure 5 is an end elevational view of the sealing member provided in accordance with the principles of the present invention and;

Figure 6 is a fragmentary cross sectional. view enlarged and a second gear shaft extension 19 which projects out of the housing or casing 11 andwhich' is splined to a driving member 20 adapted to be connected to a source of power. interposed between the housing or casing 11 and the gear shaft extension 19 and is retained in place by a cover member 22 attached to the casing ll. It will be understood that O ringv sealing members and recesses for receiving same may be incorporated throughout the pump for effecting seals between related adjoining surfaces established by'the pump components.

Thedriven gear 17 has a first gear shaft extension 23 andfa second gear shaft extension 24. The gear shaft]

extensions

19 and 24 are journalled in a corresponding pair of bearing surfaces indicated at 26' and 27 respec tively provided by the casing 11 That portion of the casing'lI also provides a radially extending sealing surface- 28 which engages and seals against and adjoining.

side face of each

corresponding gear

16 and 17.

At the opposite side of the gears 16and 17, the movable pressure loaded bearing, end plate means of the present invention are provided, each

gear

16 and 17 having a bearing end plate member 30 associated therewith.

Detailed description of a single bearing end plate member 30 will suflice for both of the bearing end plate members and in'this'connection, reference may be had to theenlarged details shown in Figures 2, 3 and 4.

Each of the bearing end plate members 30 comprises a generally cylindrical spool-type bushing member having a generally circular outer periphery 31. A chordal flat portion 32 (Fi'g.' 2) establishes an abutment joint between a pair of the adjoining

members

30, 30.

Each bushing 30' has a friction side or a sealing surface 33 which is adapted to engage and seal against the adjoining side face of a

corresponding gear

16 or 17.

Each bushing 30 also has an irregularly'shaped nonfriction side which together with means. including a portion' of' the housing or casing 11 forms a plurality of circumferentially spaced localized and confined pressure control chambers herein numbered serially 34, 35, 36, 37, 38, 39 and 40 In cross. section, or, in viewing the bushing 30 from the rear, it will be noted that the configuration of the bushing 30 on the non-frictionside resembles a star, there being a plurality of circumferentially spaced fingers The usual bearing and seal assembly 21 is each indicated at 41 which are interposed between each respective pair of pressure control chambers 34-40.

The pressure control chambers 3440 being circumferentially spaced, lie axially opposite corresponding areas on the friction side or sealing surface 33 of the bushing 30 subjected to varying loads in the pumping cavity 14 of the pump 10. These varying pressure" loads increase progressively in the pumping cavity 14 from a minimum at the inlet side of the pump adjacent the inlet 12 to a maximum on the outlet side of the pump adjacent the outlet 13. Moreover, when the speed of rotation of the

gears

16 and 17 is increased, the line of action of the pressure force tends to change.

In accordance with the principles of the present invention, the quantitative value of the loading force is not only changed but, is in effect, applied at different locations because each respective pressure control chamber 344t inclusive, is separately communicated to an axially opposite portion of the pumping cavity 14 by a passageway extending axially through the bushing 30. Each of the passageways, for the sake of convenience, is indicated by the same reference numeral 42. The passageways 42 constitute generally cylindrical'openings or bores and may be counterbored as at 43 atthe sealing surface 33.

The present invention further contemplates that the pressure control chambers 34-40 be provided in an increasing number from the inlet to the discharge side of the pump. Thus, the degree of concentration is calculated to approximate the generated pressure gradient of the working fluid within the pumping cavity 14. Furthermore, it is contemplated by the present invention that the width of the respective projections or fingers 41 be progressively changed to increase the respective areas of the motive surfaces at the bottom of the respective pressure control chambers 3440. In Fig, 3, the motive surfaces are indicated by the reference numeral 46. In Fig. 4, it will be noted that the fingers 41 become progressively narrower, thereby proportionately increasing the amount of exposed area from the inlet to the outlet sides of the pump.

Each bushing 30 has a bore extending therethrough providing a bearing surface 47 for journalling a corresponding one of the

gear shaft extensions

18 and 23. In the sealing surface 33, there is provided a counterbored recess 48 which lies circumjacent the bearing surface 47. Pressure generated by the pump is communicated to the counterbored recesses 48 by a passageway 49 extending between the recesses 48 and a trapping relief 50 formed on the discharge side of each respective bushing 30. The bearing surface 47 of each bushing 30 is further characterized by one or more axially extending grooves 51 communicating with the counterbored recess 43, thereby to flood the bearing surface 47 with a coolant and lubricant.

in order to seal the pressure control chambers 3440 and in order to initially load the bushing 30 into sealing engagement with the

gears

16 and 17, a resilient and elastic sealing disk 53 is interposed between each bushing and the back adjoining wall of the casing 11. As shown in Fig. 6, the face of the seal ring 53 adjoining each bushing 3% may be provided with circumferentially spaced radially extending grooves 54 adapted to receive and seat corresponding fingers of projections 41, thereby providing projecting portions 55 which form lips extending into each corresponding pressure control chamber 34-40. The grooves 54 not only promote eflicient sealing, but also prevent relative rotation between the parts of the pump.

In operation, the arrangement described is of particular utility because the separate pressure control chambers 344t having motive surfaces of varying areas and communicating with separately spaced portions of the pumping cavity 14 operate to provide a loading force acting on the bushings 30 which is equal and opposite to a 4 varying load and which varies not only quantitatively but also varies insofar as the effective point of load concentration is concerned.

Although various minor structural modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A pressure loaded bearing end plate bushing for a gear pump comprising a friction side and a non-friction side, means on said non-friction side of said bushing forming a plurality of confined localized alternately circumferentially spaced fingers and areas, the areas increasing progressively in number from the inlet to the outlet sides of the pump and the fingers decreasing progressively in size, whereby to provide a greater effective total area of said localized areas on the outlet side of the pump, and passage means in said bushing extending from each respective one of said areas axially into said friction side of said bushing to communicate the same varying pressure forces acting on the friction side of the bushing to the corresponding localized areas on the non-friction side of the bushing.

2. In a high pressure pump, a housing having an inlet and an outlet and providing a pumping cavity, and end plate means for said cavity in said housing, said end plate means having an irregularly shaped back surface forming together with means including a portion of said housing a plurality of circumferentially spaced localized confined pressure control chambers, a finger interposed between each respective pair of. chambers, the number of chambers increasing and the Width of the fingers decreasing towards the outlet side of the pump, and a corresponding plurality of passages in said end plate means communicating each respective chamber to said cavity at a point axially opposite the corresponding chamber, thereby to vary progressively the loading force on said end plate means from the inlet side of the pump to the outlet side of the pump in degree to approximate the generated pressure gradient in the pumping cavity.

3. in a high pressure pump as defined in claim 2, a

flexible sealing member interposed between said housing and said end plate means having a plurality of face segments corresponding in size and shape to said chambers to seal said chambers.

4. in a high pressure pump, a housing having an inlet and an outlet and providinga pumping cavity, rotary fluid displacement means in said pumping cavity for moving fluid from said inlet to said outlet, said housing having a second cavity adjoining said pumping cavity and being of a complementary size and shape, bearing end plate means in said second cavity for sealing and engaging against an adjoining side face of said rotary fluid displacement means, said bearing end plate means having a friction side forming a sealing surface for engaging an adjoining side face of the rotary fluid displacement means and a non-friction side, said non-friction side being star-shaped in configuration and having integral therewith a plurality of alternately circumferentially spaced radially extending finger projections and pressure control chambers, and separate passageways for each chamber extending through said bearing end plate means and intersecting said friction side for communicating varying pressures to said pressure control chambers, thereby to progressively vary the loading force acting on the bearing end plate means from the inlet to the outlet side of the pump for balancing the unequal pressure forces in the pumping cavity.

5. In a high pressure pump, a housing having an inlet and an outlet and providing a pumping cavity, a second cavity adjoining said pumping cavity and being of a complementary size and shape with respect thereto, hearing end plate means in said second cavity having a friction side providing a sealing surface for engaging and sealing against an adjoining side face of rotary fluid displacement means in said pumping cavity, said bearing end plate means having a non-friction side characterized by the formation thereon of a plurality of alternately circumferentially spaced radially extending finger projections and pressure control chambers in said bearing end plate means, and a flexible sealing member interposed between said housing and said bearing end plate means having a face particularly characterized by the formation thereon of a plurality of face segments fitting in said pressure control chambers to efiect a seal of each chamber with respect to said housing, and means communicating pressure generated by said pump into said pressure control chambers.

6. In a high pressure pump as defined in claim 5, each respective pressure control chamber having motive surfaces of size increasing in effective motive surface area towards the discharge side of the pump, thereby to approximate the pressure gradient in the pumping cavity.

6 7. In a high pressure pump as defined in claim 5, said pressure control chambers being disposed in an order of increasing number from the inlet to the discharge side of the pump and the corresponding interposed finger projections decreasing in Width, thereby to increase the total loading force of the bearing end plate means towards the discharge side of the pump.

References Cited in the file of this patent UNITED STATES PATENTS 2,044,873 Beust June 23, 1936 2,707,441 Drennen May 3, 1955 2,714,856 Kane Aug. 9, 1955 2,756,681 Oliver July 31, 1956 2,809,592 Miller et a1 Oct. 15, 1957 FOREIGN PATENTS 659,681 Great Britain Oct. 24, 1951 1,105,262 France June 29, 1955