US2980028A

US2980028A - Gear pump journal and face lubrication

Info

Publication number: US2980028A
Application number: US678812A
Authority: US
Inventors: William V Edwards; Donald L Lorenz
Original assignee: Thompson Ramo Wooldridge Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1957-08-19
Filing date: 1957-08-19
Publication date: 1961-04-18
Anticipated expiration: 1978-04-18

Description

April 18, 19 w. v. EDWARDS ET AL 2,980,028

GEAR PUMP JOURNAL AND FACE LUBRICATION Filed Aug. 19, 1957 2 Sheets-Sheet 1 IYJ/EYYZUTE WU/Lam V Edwards April 1961 w. v. EDWARDS ET AL 2,980,028

GEAR PUMP JOURNAL AND FACE LUBRICATION Filed Aug. 19, 1957 2 Sheets-Sheet 2 Fl Z /a 13/ I33 /5o /50 39/ man /5z I i 4 180a /30 A ,g I /41 1 i 4M2 m5 m2 900. 4 13! M7 w M l5!) 94 W 650a I I42 mm a 90b 94 T q I92 90 I230 [w 2 ;..Z q. 5

Will/Lam Edwards Dqzza/d L. Lorenz United States Patent 2,980,02s q GEAR PUMP JOURNAL AND FACE LUBRICATIO William v. Edwards, Willowick, and Donald L. Lorenz, Euclid, Ohio, assignors to ThompsonRamo Wooldridge Inc., a corporation of Ohio Filed Aug. 19, 19515. No. 678,812

Claims. 01. 103-126) This inventionrelates to afluid pump and particularly to a pressure-loaded gear-type pump construction having the pump for efficiently and reliably lubricating said surfaces with a minimum loss of fluid from the work ing path of the pump. 7 I p s A further object of the present invention is to provide a novel gear pump construction having meansfor providing a pulsating type of flow torelativelymoving surfaces of the pump. 7 I

Another object of the present invention is to provide a bushing for a pressure-loaded gear pump having novel means for lubricating. the bearing and lateral sealing surfaces thereof. n a v Still another object of the present invention is to provide a novel pump construction having a region about the periphery of the pump impeller between the inlet and outlet chambers of the pump where fluid pressure has a relatively large amplitude fluctuation'during operation of the pumpin combination with a lubricating passage communicating with said region .offluctuationg' pressure and with relatively moving surfaces of said pump.

Other objects, features and advantages of the present drawings, in which: g

Figure 1 is a longitudinal'sectional view showing a gear-type fuel pump, incorporatingthe features of the present invention; 5

invention would be apparent from the following detailed description taken in connection with the accompanying f Figure 2 is a side elevational view showing a bearing 3 member constructed in accordance with the principles and teachings of the present invention;

Figure3 is a longitudinal sect onal viewof the bearing member of Figure 2; j V

" Figure 4 is a fragmentary longitudinal sectional illustrating thecooperation between the bearin'girnember of Figures 2 and 3 and the gear impelling'means;

QgFigu re 5 is. a fragmentary e'nd. elevational view'offa modified bearing member in accordance with the present invention; land 1' Figure 6 is a fragmentary longitudinal sectional view taken along the line VI-VI'of Figure 5. ...As,sh0wn on the drawings;

ice

17, forms a pump housing for the multiple pump 10 in which is contained a first centrifugal pumping stage indicated generally at 21 in series with a positive-displacement pumping stage consisting of two gear pump units indicated generally at 22 and 23, respectively. Each of the

gear pump units

22 and 23 is similar in structural and functional characteristics. Fluid at the inlet 18 is initially pressurized by the centrifugal stage 21 and is supplied for further pressurization to the positive-

displacement pumping stages

22 and 23 in parallel.

The cover member 14 is provided with the usual seal and bearing assembly indicated generally at 24 thereby to support a rotatable driving member indicated at 26 and including a splincd shaft portion 27 adapted to be connected to a sourceof power supply, for example, the accessory drive of an aircraft jet engine if the pump 10 is employed as the fuel pump for the jet engine fuel system.

The driving member 26 extends inwardly of the pump housing and has a thrust flange 28 formed thereon con centrically surrounding a bore 29 which is partially splincd as at 30 to couple with the complementary splines formed on the end of a firstshaft member formed as a tubular quill shaft and indicated at 31.

The driving member 26 is further provided with a generally cylindrical'collar 32, the walls of which surround a bore 33. The bore 33 has formed inthe walls thereof a splincd portion indicated at 34 which forms a coupling'for the external splines formed on a shaftextension 36 on a driver gear 37 of the gear pump unit 23. The -c0llar-32 is provided with a first reduced shear neck 38 outwardly of the spline connection between the collar 32 and the shaft extension 36. By virtue of such provision, any abnormal force resulting from jamming or seizure of the gear pump unit 23 will effect torsional yielde ing of the reduced shear neck 38, thereby interrupting further operation of the gear pump unit 23. V The driver gear '37 is formed with a hollow bore 39 extending therethrough. .Thus, the tubular quill shaft 31 extends inwardly through the bore 39 and has formed on the end thereof external splines 40 which mate with complementary internal splines formed in the bore 41 of a gear shaft extension 42 on'the driver gear 43 of the gear pumpunit 22. The tubular quillshaft 31 is formed with a reduced shear neck 44 outwardly of the splincd connection between the shaft 31 and the driver gear 43. j Thus, if'any abnormal.force'results from jamming or seizure'of the gear pump unit 22, the shear neck 44 will, yield torsionally -Thefend section 17 of the pump housing has a bore 48 formed therein in which is received a bearing sleeve 49 for journaling a shaft portion 50 provided on a gear 51. The gear 51 forms part of'a speed proportioning means comprising a gear train rotatable in a gear chamber 52 formed in the end of the casing '11. .The gear The principles and teachings of thepresent invention are particularly applicable to..a geartype pump such as indicated generally by the reference numeral 10. in Figure. 1. Such a pump comprises a casing 11 which has an end section 12 connected to the casing ll a pluralityfof fasteners 13. Acover member 14 is connected .tothe endsection 12 by a plurality of fasteners 16L End section 17 provides avclosure for the opposite end. of casing 11 and and hast-a fluid inlet 18. therein;

i The casing 11 togetherwith theend sections-Hamid shaft member. 57 is: provided with external splines as 51 is further steadied in its rotation by an axialbearing ring '53 supported by a radially inwardly extending strut 54 carried by the end section 17 of the pump'housing.

A bore extends through the gear 51 and its shaft por tion' 50'andis provided with splines 56 mating with a complementary plurality of external splines on the end ofa second shaft member 57. The. second shaft member 57 extends through the hollow bore 41' formed in the driver gear .43 of the gear pump unit 22 and .extends a into a bore. 59 formed in the tubular shaft member 3 1. T he shaft 3l. is provided ,with internal splinesjand ;the

m. l a :2 a

shaft 57 with the gear -1.

r c 2.98am;

shown at 60, thereby to couple the shaft members 31 and 57 for corotation.

The end section 17 of the pump housing is formed with a volute pumping chamber 61 in which is rotated a centrifugal impeller 62. The impeller 62 is keyed as at 63 and locked as at 64 to a shaft member 66 journaled in a plate-type insert 67 fastened in the end section 17 of the pump housing and providing both radial and axial bearing surfaces. At the end of the shaft member 66, there is provided a gear 68 meshing with the gear 51.

For greatest efficiency, the centrifugal impeller 62 should be rotated at higher speed than the

gear pump units

22 and 23. Accordingly, the gear 51 is much larger in diameter than the gear 68, thereby permitting the gear train to function as a speed-proportioning means within the gear chamber 52 and thereby permitting the centrifugal impeller 62 to rotate in unison with the gear pump units 2-2. and 23 but at a much greater rotational speed.

The shaft member 57 is formed with a reduced shear neck 70 intermediate the spline Connection of the shaft 57 with the shaft 31 and the spline connection of the In this particular embodiment, it will be noted that the reduced shear neck 70 is located outwardly of the shear neck 44. By virtue of such provision, any abnormal force resulting from jamming or seizure of the centrifugal impeller 62 will cause the shear neck 70 to yield torsionally, thereby interrupting the further operation of the impeller 62 without interrupting the continued operation of the

gear pump units

22 and 23.

It will be noted that each of the reduced shear necks including the shear neck 38, the shear neck 44 and the shear neck 70 is in register with the opening in the end of the pump closed by the cover member 14. Thus, separate parts can be conveniently replaced without requiring disassembly of the entire pump since the broken parts can be conveniently removed from the pump merely by removing the cover member 14 at the end of the casing.

As shown in Figure 1 and in more detail in Figures 2 and 4, the

gear pump units

22 and 23 may be provided with generally similar bushing members, and for convenience only the details of the gear pump unit 22 will be described herein. The construction of the gear pump unit 23 will be apparent from the followingdescription of the gear pump unit 22.

As illustrated in Figure 1, gear pump unit 22 comprises a driver gear 43 having a series of peripherally spaced gear teeth such as 43a meshing with teeth 90a of a driven gear 90. The gears 43 and 90 are provided with

integral shaft portions

42, 92, 93 and 94 journalled in bearing members or bushings 100, 101, 102 and 103 A retainer ring 107 is secured against a shoulder 11a of the casing 11 by a plurality of fasteners such as indicated at 109 to retain the pump unit 22 within its cavity in the casing 11. The casing 11 is provided with acentral shoulder 11b against which are seated springs such as indicated at 111 for urging the bearing members 100 and 102 against one side of the gears 43 and 90. The space between the shoulder 11b and the opposing face of'each of the bearing members 100 and 102 provides a pressure chamber 112 for receiving fluid at the discharge pressure of pump unit 22 to bias the movable bearing members 100 and 102 against the gears 43 and 90. Suitablesealing rings such as indicated at 114 and 115 may be provided for isolating the pressure chamber 112 associated with the movable bearing members 100 and 102 from adjacent spaces such as indicated at 120 which may be 7 generally at the inlet pressure of the pump section 22, the space 126 being direct in fluid :communication with the discharge side of centrifugal impeller 21.-

The bearing members 100, 101, 102 and 103are gen- 4 103 comprises a generally tubular body portion 130 with a radially outwardly extending flange 131 at one end. The flange 131 has a front face 133 which forms a lateral sealing face engaging the adjoining side face of gear 90 as illustrated in Figure 4 to seal the fluid in the gear tooth spaces between gear teeth such as 90a. Flange 131 is provided with a chordal edge as indicated at to complement the generally figure Sshaped pumping cavity in which the gears rotate. Bearing member 101 associated with driver gear 43 has a mating chordal edge face 141, Figure 1, abutting the edge face 140 of flange 131.

The sealing face 133 of bearing member 103 is provided with an inlet relief recess 144 which provides an open region adjacent the tooth spaces on the inlet side of the pump to facilitate filling of the tooth spaces with fluid from the inlet chamber of the pump unit. ing face 133 is further provided withan outlet relief recess146 as seen in Figure 2 which is located adjacent the tooth spaces on the. outlet side of the pump to form a trapping relief and to improve the discharge characters istics of the pump.

The outer periphery of the sealing face 133 is indicated at 150 inFigure 2 and is concentric with the axis of the bearing member 103. For a portion of the outer periphery 150, there is provided a chamfered portion 152 forming a passage intercommunicating the tooth spaces at a portion of the periphery of the bearing member 103 with the relief recess 146 at the discharge side of the pump to tend to conduct fluid at discharge pressure to the tooth spaces which are registered with portion 152 at a given instant during rotation of gear 90.

At the radially innermost portion of the sealing surface 133, there is provided a chamfered relief which operates to remove bearing load from bushing 103 adjacent the juncture of shaft portion 94 with gear 90. The bushing 103 has an axial bore 162 providing a bearing surface 130a for journaling shaft portion 94 of gear 90. Extending longitudinally of the bearing surface 130:: is a groove 164 for distributing any fluid which may be at the relief portion 160 into the bearing area to assist in lubricating and cooling the bearing surface 130a.

Spaced longitudinally from the flange 131 on the bush? ing 103 is a second radially outwardly extending flange 166 having an outer peripheral surface 167 generally concentric to the axis of the bushing 103 and of contour corresponding to the periphery 150 of flange 131 for transmitting bearing support from the casing 11 to the bearing surface 130:1.

In accordance with the principles and teachings of the present invention, means comprising a groove 180, Figures 2, 3 and 4, is provided for diverting a controlled amount of fluid from the working path of the pump. The working path of the pump may be considered to be the path taken by fluid which is transported by the tooth spaces, from a position in registry with inlet relief 144 to a position in registry with discharge relief 146. As the teeth such as indicated at 90a move along the working path from inlet relief 144 toward outlet relief 146 fluid pressure inthe tooth spaces tends to progressively increase from inlet'pressure to discharge pressure. With respect to a given region of the working path such as that communicating with groove. 180, pressure pulsates between a relatively low pressure and a relativelyhigher pressure. as the successive teeth 90a approach the groove 1. 0 a d th mo pa t ro e a y t e groove is of an extent to overlap the annular gear teeth engagipg portion 133b of sealing face 133 and thus to communicate directly with the successive gear tooth spaces as they move past the groove, For this purpose, enda of the groove extends radially beyond'the'root diameter of gear 90 indicated at 90b in Figure 4. In the illustrated embodiment, the groove 180 'at its radially inner end 180b extends into direct fluid communication with the recess provided by the chamfered portion 160 of the bearing member 103 to supplylubricating fluid to The seal the 'journal surface 130a via groove 164. "The groove ing region thereof indicated at 133a radially inwardly of the root diameter of the gear 90. It is found that this construction provides proper lubrication for the'lateral sealing face 133a and bearing surface 130a with much less loss of flow than a direct bleed to a constant high pressure. a

By way of example of preferred dimensions of groove 180, in the illustrated embodiment the end 180a of the groove 180 may terminate .690 inch from the center line or axis of the bushing 103 and may have a depth of A of aniinch and a width of .016 inch. The root diameter of the gear 90 maybe of the order of 1 and inches, so that the overlap of the groove 180 with respect to the root diameter of gear 90 may be of the order of .02 inch. As seen in Figure 2, the groove 180 is preferably located substantially midway between the inlet relief recess 144 and the end of the chamfered portion 152 indicated at 152a nearest the inlet relief 144.

The b ushing 101 indicated in Figure 1 is a mirror image of the bushing 103 in every respect and is provided with a groove corresponding to groove 180 in the corresponding position intermediate its inlet relief and a chamfer portion such as indicated at 152 for the bushing 103. Similarly,'each of the movable bushings such as indicated at 102 in Figure 4 is provided with a chamfer portion such as indicated at 192 adjacent an internal journal surface 102a and is provided with a lubricating groove such as indicated at 194 positioned relative to the inlet relief and chamfer portion communicating with the discharge relief in the same manner as indicated for the groove 180 in Figure 2. The construction of the movable bearing members such as 102 will be apparent to those skilled in theart from Figures 1 and 4, but further details of such movable bearing members are disclosed in the Edwards et al. application U.S. Serial No. 636,772, filed January 28, 1957. The disclosure of this copending application is incorporated herein by reference with respect to its entire disclosure. 1

Figures 5 and 6' illustrate a modified form of lubricating groove which is designated by reference numeral 196. This groove 196 corresponds identically to the groove 180 in dimensions and position except for providing a straight axial end wall portion 197 at right anglesto bottom portion 198 of groove 196 instead of the end portion 180a which has an end wall portion 1800 which is curved radially inwardly and is not at right angles with respect to the bottom portion of groove 180 indicated at 199 in Figure 3. Other parts of the bushing of Figures 5 and 6 have been given the same reference numerals as in Figures 2 and 3 since the parts may be otherwise identical. It will be apparent that the groove 196 will function in a similar manner as described for the groove 180 so that further description of the function of the groove 196 is deemed unnecessary.

It will be apparent that many modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

We claim as our invention:

1. In combination, a pump having an inlet region and an outlet region and having gear-type impeller means for moving fluid along a working path from said inlet region to said outlet region during which the pressure of the fluid is progressively increased from an inlet pressure at said inlet region to an outlet pressure at said outlet region. said impeller means comprising a gear having a series of teeth defining spaces therebetween for receiv-;

ing and transporting fluid along said working'path and said spaces extending inwardly to the root diameter of said gear, the teeth moving progressively 'fromthe inlet region to thevoutlet regionalong the working path and then moving from the outlet region to the inlet region i,

along a non-working path,shaft means for mounting said gear, a bearing member having aninternal bore receiving said shaft means and having a lateral face engaging a sideof said gear, said lateral face having means defining apassage communicating with said working path at a position intermediate said inlet and outlet regions and extending from a point slightly radially outwardly of the root diameter of said gear to a point communicating with the bore of saidbea'ring member, said passage being substantially unobstructed to effectively communicate substantially thefull pressure at said intermediate position of said'working path to said bore of said bearing member, and, being substantially isolated from said inlet region and said outlet region to provide a pressure intermediate inlet and outlet pressures.

2. In combination, a pump having'inlet and outlet regions and having gear-type impeller means having a series of teeth defining fluid receiving spaces therebetween for moving fluid along a workingpath between said inlet and outlet regions during which the pressure of the fluid is progressively increased from an inlet pressure at the inlet region to an outlet pressureat the outlet region, the teeth then moving along a non-working path from'the outlet region to'the, inlet region, shaft means for-mounting'said impeller means, bearing means having a lateral face-engaging a side ofgsaid impeller means and having an internal bearing surface journalling said shaft means, said lateral face having a radially extending groove for communicating at one end with the spaces between successive teeth of the impeller means at said working path as the impeller means rotates and communicating at the other end with said internal bearing surface of said bearing means, and means comprising the disposition of said groove relative to said working path whereby. a pulsating fluid pressure is generated at the end of said groove communicating with said spaces between successive teeth of the impeller means for supplying fiuid to said internal bearing surface.

3. A bushing for a pressure-loaded gear pump comprising a generally annular member having an axial bore and having a lateral gear engaging face at one end there of, said lateral gear engaging face having a radially inner annular portion for engaging a gear journalled thereby radially inwardly of the root diameter of the gear and a radially outer annular portion for engaging a gear journalled thereby radially outwardly of the root diameter of the gear, said member having inlet and outlet regions at spaced portions of the periphery thereof and having a peripheral passage extending from the outlet region to ward the inlet region with one end thereof terminating 1n spaced relation to said inlet region to provide a porannular portion. of said lateral gear engaging face to a point substantially directly communicating with the axial' bore of said member for lubrication of said lateral face and said axial bore of said member.

4. A bushing for a pressure-loaded gear pump comprising a generally annular member having an axial bore and a lateral sealing face at one axial end thereof, said 1 member having inlet and outlet relief regions adjacent the periphery thereof and having a longitudinal groove extending-along the bore thereof and'having a peripheral groove extending from the outlet relief region toward the inlet relief region terminating-in spaced relation from i the inlet relief region to provide a portion'of the pe-" riphery of the member where fluid is progressivelyv pressurized from inlet pressure to outlet pressure, and means defining a mam groove disposedat said portion of the periphery where fluid is pressurizedand of radial extent to communicate at one end with pressurized fluid and 7 to communicate at the other end with the groove along said bore to supply lubricating fluid to said bore.

5. In combination, a pump having inlet and outlet regions and having rotatable impeller means with a series of peripherally spaced fluid receiving spaces for moving fiuid along a working path from said inlet region to said outlet region, a bushing having a lateral face in engagement with one side of said impeller means for laterally sealing said fluid receiving spaces and having a peripheral passage for aflording intercommunication between a series of said fluid receiving spaces instantaneously in registry therewith during rotation of said impeller means, said working path having, a pressurizing region between said inlet region and the region thereof communicating with said peripheral passage, said lateral face of said bushing having a straight groove extending generally radially and having one end terminating radially outwardly of the root diameter of said impeller means to communicate with each of the spaces of the impeller means in succession at said pressurizing region of said working path, said groove communicating with only one fluid receiving space at a time to provide a pulsating pressure from the successive spaces at said 8 munication with said axial bore for supplying'a pulsating lubricating pressure to said bore, and said groove being substantially isolated from said inlet region and said outlet region to provide a pressure amplitude at said groove intermediate the pressures at said inlet region and said outlet region.

References Cited in the file of this patent UNITED STATES PATENTS 7 1,271,970 Wood July 9, 1918 1,372,576 Tullrnann Mar. 22, 1921 1,682,842 I-Iamer Sept. 4, 1928 1,795,579 Storey Mar. 10, 1931 1,972,271 McIntyre Sept. 4, 1934 2,281,767 Heckert May 5, 1942 2,541,010 Ungar Feb. 6, 1951 2,624,287 Ilyin Jan. 6, 1953 2,676,548 Lauck Apr. 27, 1954 2,735,372 Booth et a1. Feb. 21, 1956 2,756,684 Renzo July- 31, 1956 2,775,209 Albright Dec. 25, 1956 2,808,007 Gaubatz Oct. 1, 1957 2,816,511 Korkowski et a1 Dec. 17, 1957 2,820,416 Compton Ian. 21, 1958 2,823,617 Compton Feb. 18, 1958 2,885,965

Haberland May 12, 1959 "T -la