US2641192A

US2641192A - Gear pump

Info

Publication number: US2641192A
Application number: US159673A
Authority: US
Inventors: Paul G Lindberg
Original assignee: LINDBERG TRUST
Current assignee: LINDBERG TRUST
Priority date: 1950-05-03
Filing date: 1950-05-03
Publication date: 1953-06-09
Anticipated expiration: 1970-06-09

Description

June 9, 1953 P, G, LINDBERG 2,641,192

GEAR PUMP Filed May 3, 1950 INV T PAUL G. L/ BE l MW ATTORNEY June 9, 1953 P. G. LINDBERG 2,641,192

GEAR PUMP Filed May 5, 195o 3 sheets-sheet 3 j *Y J, a

'l mi \N i@ JNVENToR. PAUL G. L/NDaERG /M/"QML/ ATTORNEY Patented `lune 9, 1953 GEAR PUMP Paul G. Lindberg, Willoughby, Ohio, assignor to Lindberg Trust, Cleveland, Ohio, a trust of Ohio Application May 3, 1950, Serial No. 159,673

(Cl. S- 126) 8 Claims.

This invention relates to pressure fluid gear pumps and has for one of its primary objects to provide an improved gear pump of simplified construction and increased efficiency.

Another object is to provide a construction for automatically maintaining pressure responsive longitudinally iioating bearing bushings in sealed contact with the side faces of the associated gears.

Another object is to provide an improved fluid pressure loaded iioating end bushing construction which is also self-sealing with respect to the pump housing.

Another object is to provide an improved floating end bearing construction which is in the form of an elongated one-piece straight wall bushing to engage both adjacent journals of .the two gears and fill up the pump housing cavity so as to be a single self-sealing bushing that necessitates no sealing accessories.

, Another object is to provide such a one-piece floating end bushing with a pressure responsive sliding means for automatically maintaining proper pressure loading and alignment and sealing of the bushing with the gear faces and the pump housing.

Another object is to provide such a one-piece floating end bushing and single pressure pin loading device therefor that will maintain proper pressure loading, alignment and sealing and avoid cocking and which bushing may support the gear journals as a plain bushing or have rolling bearing elements therein to support the gear journals.

With .the foregoing and other objects in view, the invention resides in the combination oi parts and in the details of construction hereinafter set forth in the following specification and appended claims, certain embodiments thereof being illustrated in the accompanying drawings, in which:

Figure 1 is a view in elevation of the pressure inlet and outlet end of the uid pressure gear Dump;

Figure 2 is a top plan view of the pump;

Figure 3 is a View in section taken through the pump along line 3--3 of Figure l;

Figure 4 is a view partly in top elevation and partly in transverse section of the pump;

Figure 5 is a View in section taken along line 5-5 of Figure 4;

Figure 6 is a View similar to Figure 3, showing the gear journals supported by needle bearings in the bushings;

Figure 7 is a View in perspective of one of the gear journal bushings; and

Figure 8 is a view in section taken along line 8--8 of Figure 6.

Referring more particularly to the drawings, the main gear pump housing I has secured thereto by bolts 2 a housing 3 for the uid inlet 4 and outlet 5.

The pump is shown to comprise two pump gears 6 and 'I with meshing

teeth

3 and 9. On opposite sides of teeth 8, gear 6 is provided with journals Ill and I I and on opposite sides of teeth 9, gear 'I is provided with journals I2 and I3. Journal I I of gear 3 and journal I3 of gear 1 are mounted to rotate in an elongated unfianged one-piece straight side bushing I4 which is mounted to be longitudinally slidable on the inner surface of housing member I5 and which fills up the housing cavity. Such a bushing I4 is shown in perspective in Figure '7. Journal Ill of gear E and journal I2 of gear 'I are mounted to rotate in a similar elongated unflanged one-piece straight side bushing I6 that is likewise mounted to be longitudinally slidable on the inner surface of the housing and likewise fills up the housing cavity. The opposed faces II and I8 of bushings I4 and I6 are pressure loaded to engage the opposite side faces of gear teeth 8 of gear Ii in uid sealing relationship, and the opposed faces I9 and 20 of bushings I4 and I6 are pressure loaded to engage the opposite side faces of gear teeth 9 of gear I in uid sealing relationship. Gears and I are provided with longitudinal bores 2I and 22.

Journal I0 of gear 6 has a reduced extension 23 that is splined to a coupling member 24 having a flange 25 that engages with a bearing ring 26, the opposite side of which presses against a flexible seal ring 2l, that, in turn, presses against a collar 28 provided `with an annular seal ring 2S between it and the housing and secured therein by a snap ring 30. Coupling member 24 is secured by pin 3| to the splined gear connector 32. A compression coil spring 33, bearing inwardly against gear journal I0 is provided to eliminate end play of gear 6 and affecting the seal assembly at this end of the gear.

Housings I and 3 when connected together are uid sealed by

rings

34 and 35. The fluid from inlet 4 passes through inlet chamber 36 to gear 'I and from gear 6 the iiuid passes through outlet passage 31 to outlet 5.

Mounted in housing 3 is a spring and pressure loaded slidable pin 38 provided with an annular seal ring 39. It is normally urged by a compression coil spring 40 in the recessed head of the plug to initially resiliently force the onepiece gear bushing I4 to the left, as viewed in Figure 4, which leaves an axial chamber 4I between the housing 3 and bushing i4.

Fluid pressure is fed in from the high pressure side from passage 3l through passage i8 in behind and in the recessed head of oating pin 38 to force the pin 38 to the left to fluid pressure load the .bushing I4. Pressure loaded pin 36 is located approximately opposite the center of internal pressure and on the horizontal centerline, but displaced outwardly from the vertical centerline, as shown in dotted lines in Figure 8. The resulting action of pressure fluid from the high pressure, or discharge, side on the pin 38 is to pressure load the bushings. Pressure iluid in space 50 behind 'bushing IB and behind spring 33 is vented through passage 5I and bore 2I to space 4I behind bushing I4.

Housing 3 is provided with a bore 42 to ,receive a retaining plug 43 and a coil spring 44, urging a ball valve 45 to normally close passage 46 that communicates with passage 41 leading to axial chamber 4I. This provides a low pressure relief valve for venting chamber 4I to low pressure through passage 4S to the inlet passage 36.

The one-piece floating bushings lI4 and I6 not only completely iill the housing cavities, 'but are also elongated and straight sided with no flanges. `The intimate contact of their outer surfaces throughout their entire lengths with the inner surface of the housing provides for an eiective seal against fluid leakage. They are thus selfsealing and require no additional sealing accessories. Another advantage of this one-piece iloating bushing construction lies in the fact that it is self-aligning with respect to the geai journais, the gear faces and the housing, with virtually no tendency to cock in their pressure responsive sliding movements. This latter is especially true because the single bushing I4 is pressure loaded by the single pressure loaded pin 38 ,f

which is located approximately opposite the center of internal pressure.

In my gear pump construction, I have considerably reduced the number of essential operating parts. By reason `of employing single one-piece straight sided iloating bushings, I am able to employ a slidable pressure pin, or piston, 38 for effectively pressure loading the bushing I4 by applying the fluid pressure from the high pressure side to the pin 38. Moreover, in such a construction I und it unnecessary to employ insert plugs to insure against leakage. The fluid that acciunulates in space 4I, upon movement of bushing I4, is readily vented past the W pressure 'ball check valve to the low pressure side. Thus I find it unnecessary to provide any relief recesses between the side faces of the gears and the bushings.

All of this is in contrast to conventional gear pumps employing separate pressure loaded bushings for each journal of each gear in 'which case it is necessary to use rubber inserts as fluid seals. Such inserts are placed in drilled holes on the low pressure side connecting the ilats of both the adjacent floating bushings and the pump housing to keep the high pressure in chambers behind the bushings from by-passing directly to the pump inlet. Failure of such rubber inserts results in failure of the pump. Conventional pumps also employ reliefs on the faces of the flanges of the oating bushings as a means for controlling the magnitude of the pressure loading. Conventional gear pump construction, moreover, precludes the use of rolling bearing elements, such as ball, roller or needle bearings, inasmuch as the cocking tendency of the bushings employed for each `journal of each gear results in an overload on the bearing elements.

Due to the nature of my construction, however, I may employ plain bushings, as described, or I may also employ rolling bearing elements carried by the bushings to support the gear journals. I have shown such an arrangement in Figure 6, in which the general overall construction remains the same as previously described, with the exception that I have shown needle bearings 52 carried by bushing I4 to support journal II of gear 6 and needle bearings 53, also carried 'by the same bushing I4 to support journal I3 of gear I. Likewise, I have shown needle bearings 54 carried by bushing I6 to support journal I0 of gear 6 and needle bearings 55 carried by the same bushing I6 to support journal I2 of gear 'I.

While I have described as a preferred embodiment of my invention the use of a single pressure responsive floating pin 38 for pressure load- .ing the one-piece bushing I4, in some instances it may be desirable to employ more than one of such pins when it is desired to more evenly distribute the pressure loading force across the back face of the sliding bushing I4 when the latter is of larger sizes in larger gear pumps.

I claim:

1. A gear type pump comprising a hollow housing having a fluid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from the opposite faces thereof, an elongated one-piece bushing having flat front and back end faces, said 'bushing having straight side walls connected 'by curved ends, said bushing being mountedto have its entire periphery longitudinally slidable in contact with the inner surface of said hollow 'housing, said bushing being arranged axially of the adjacent axial faces of both of said gear members, said bushing surrounding and supporting the adjacent parallel journals of both of said gears and having a front `axial face cooperable with the adjacent axial face of its associated gear members to lprovide a seal between said bushing and said gear members and a piston slidably mounted in said auxiliary chamber in said hollow housing and in axial contact "with the back face of said bushing and a fluid passage leading from the pump discharge outlet to said auxiliary chamber on the back face of said v piston vto lprovide a fluid pressure loading on the back of said bushing to urge said bushing against saidgears.

2. A gear type pump comprising a hollow housing having a fluid inlet and outlet, said housing having a gear chamber and an auxiliary charnber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from the Upposite faces thereof, an elongated one-piece bushing having flat front and back end faces. said bushing having straight side walls connected by curved ends, said bushing being ,mounted to have its Ientire periphery longitudinally slidable in contact with the inner surface of said hollow `housing, said bushing being arranged axially o1' the adjacent axial faces of both of said gear members, said bushing surrounding and supporting Athe adjacent parallel journals of both of said gears and having a front axial face cooperable 5, with the adjacent axial face of both of its associated adjacent gear members to provide a seal between said bushing and said gear members, a piston slidably mounted in said auxiliary chamber in said hollow housing, said auxiliary chamber being axially removed from said bushing, said piston being in axial contact with the back face of said bushing and a fluid passage leading from the pump discharge outlet to said auxiliary chamber on the back face of said piston to provide a fluid pressure loading on the back face of said bushing to urge said bushing against said gears.

3. A gear type pump comprising a hollow housing having a fluid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from the opposite faces thereofan elongated one-piece bushing having flat front and back end faces, said bushing` having straight side walls connected by curved ends, said bushing being mountedlto have its entire periphery longitudinally slidable in contact with the inner surface of said hollow housing, said bushing being arranged axially of the adjacent axial faces of both of said gear members, said bushing surrounding and supporting the adjacent parallel journals of both of said gears and having a front axial face cooperable with the adjacent axial face of its associated adjacent gear members to provide a seal between said bushing and said gear members, a piston slidably mounted in said auxiliary chamber in said hollow housing, said auxiliary chamber being axially removed from said bushing and of greater axial length than said piston, said piston being in contact with the back face of said bushing and a fluid passage leading from the pump discharge outlet to said auxiliary chamber on the back face of said piston to provide a fluid pressure loading on the back face of said bushing to urge said bushing against said gears.

4. A gear type pump comprising a hollow housing having a liquid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from theopposite faces thereof, an elongated one-piece bushing having ,flat front and back end faces, said bushing having straight side walls connectedzby curved ends, said bushing being mounted to have its entire periphery longitudinally slidable in contact with the inner surface of said hollow housing, said bushing being arranged axially of the adjacent axial faces of both of said gear members, said bushing surrounding and supporting the adjacent parallel journals of both of said gears and having a front axial face cooperable with the adjacent axial faces of both of said gear members to provide a seal between said bushing and said gear members, a piston slidably mounted in said auxiliary chamber in said hollow housing, said auxiliary chamber being axially removed from said bushing and of greater axial length than said piston, said piston being in contact with the back face of said bushing to urge said bushing against said gears, a liquid passage leading from the pump discharge outlet to said auxiliary chamber on the back face of said pin to provide a liquid pressure loading on the back face of said bushing and venting means for venting 6, liquid from any space between said bushing and said gear journals and between said bushing and said housing to the low pressure inlet side of said pump.

5. A gear type pump comprising a hollow housing having a liquid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from the opposite faces thereof, an elongated one-piece bushing having flat front and back end faces, said bushing having straight side walls connected by curved ends, said bushing being mounted to have its entire periphery longitudinally slidable in contact with the inner surface of said hollow housing, said bushing being arranged axially of the adjacent axial faces of both of said gear members, said bushing surrounding and supporting the adjacent parallel journals of both of saidgears and having a front axial face cooperable with the adjacent axial faces of both of said gear 'members to lprovide a seal between said bushing and said gear members and a piston slidably mounted in said auxiliary chamber in said hollow housing, said auxiliary chamber being axially removed from said bushing and of greater axial length than said piston, said piston being in contact' with the back face of said bushing to urge said bushing against said gears, a liquid passage leading from the pump discharge outlet to said auxiliary chamber on the back face of said piston to provide a liquid pressure loading on the back face of said bushing and venting means, including a low pressure relief valve therein, for venting liquid from any space between said bushing and said gear journals and between said bushing and said housing to the low pressure inlet side of said pump.

6. A gear type pump comprising a hollow housing having a fluid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear members having journals extending from the opposite faces thereof, a pair of unilanged elongated one-piece bushings, each having a flat front and back end face, each bushing having straight side walls connected by curved ends, each bushing being mounted to have its entire periphery longitudinally slidable in contact with the inner surface of said hollow housing, said bushings being arranged one on each side of said pair of gear members and axially adjacent the two opposite axial faces of both of said gear members, each of said bushings surrounding and supporting the adjacent parallel journals of both of said gears and having a front axial face cooperable with the adjacent axial face of its associated gear members to provide a seal between said bushings and said gear mem-bers and a piston slidably mounted in said auxiliary chamber in said hollow housing and in axial contact with the back face of one of said bushing members and a uid passage leading from the pump discharge outlet to said piston to provide a fluid pressure loading on the back face of said last named bushing.

'7. A gear type pump comprising a hollow housing having a fluid inlet and outlet, said housing having a gear chamber and an auxiliary chamber in said housing between said gear chamber and said outlet, a pair of meshing gear members mounted in said gear chamber, each of said gear aan; raaf membersrhairingA j ournalsz. extending; from-,1th 'ie-opy4v nesite: facesf; therecfi; a; pair..- of; unanged. clon-- gatedone-piecebushingsaeach havinafaffiatlfront. and back end face, each of said bushings having straight; side walls.; connected by, curved ends, eaclifbushing being. mounted toi-have its entire'- perinhery longitudinallyY slidablerin Contact; with4 thef inner" surface of' saidhollow` housing, said.- bushings, beingiarrangedone on,;each sideiof said. paifrofigear. members.- and.1 axially adjacent the' twas opposite; axial; faces: of; both ot said gearA members;v each.Y of saidibushings suiu'ounding and supporting` the: adj acent.- parallelv journals of.y both of; said-gears and. having a; front. axial facecooperabie: wtlrthe; adjacent. axial' face of itsassor ciatedgeait'membelzfto. provide.' allsealbetweenI said; bushings; and said gear; members., a piston slid-- ably mounted: inlsa'id auxiliary chambe1'.r'in.said.- hollowr housing and in contactar-ith thebackv face.

offenes-o1"-Y said :.bushingsrto urge.4 the sama against..

s1aaid:.gea-rs-,l said: auxiliary chamber; being?l axially` removedf-rombna ofi` said; bushings and of., greater axialr length. than said piston anda iiuid" pas sage lea-dingiifrom the pump; discharge-outlet-toi said; auxiliary; chamber;v on. the bacia` face of, said. piston to; providela ud. pressureloading on the bacliifacev of; said;` bushing;

8:. A: gear typenumpcomprising a hollowy housing; having; auid inlet. andA outlet, said housing; haring;` a. gear;y chamber and an` auxiliary cham.= benin said; housing: andgbetween, said gearcham-l ben'anrtsaid; outlet, al pairfofiV meshingv gearmem bers. mounted in: said; gear chamben. each of4 said; gearmembers having' journals.; extending.v from; thefopposite; facesthereof.; ane] ong-ated one-piece, bushing having,IA dat front.. and back: end;- faces; said" bushing'havingfstraight sidewalls connected* curved ends;l said bushing being' mounted to have itsentne periphery-` longitudinally siidabl'ei in contact with the inner surfaceoi saidvv hollow:

. ing.l andal fluid passage-.leading-from thefpurrm discharge.n outletI` td said auxiliar-y, chamber 0n: the: back face. of said.` piston.tolpruvidaai fluidiv pressureloading onrthefback' face oi .said bushingj in; a; direction:v substantially opposite the.. centen ot internal pumpf-pmssure. l

BAUL. G. MNDBRG,

References; cited: im the; fue. of;l this pamrt UNITED: sauras- PATENTS