US2433222A - Pump - Google Patents

Description

M. w. HUBER 2 Sheets-Sheet 1 y No mm WHWN MII///AIAPWM .m .3, E N :,H nl; on 4m ma 5 w E 2 @N ,5. ma E em mo @N me @o am ow me L 2 @E /l S mm. 9 o@ @n m\ 7 PNL 5 S K x NN v :Snoentor Dec.` 23, 1947.

M. W. HUBER A PUK? Filed Novl 5, 1945 2 Sheets-Sheet 2 (Ittomegs Puentes Doo.,23,1947

PUMP

Mottnov'vw. noter, Watertown, `N. Y.. signor to The New York AlrlBrake Company, a, cor- `poration of New Jersey" I vimputation Novomboi s, lass, serial, No. scacco This invention relates to payralleltcylinder pumps intended to operate at rotary speeds of 3000 R; P. M. or higher against head pressures of the order of 3500 p. s. i., and the' novelty resides in means for controlling a constantly running pump by varying its displacement. The displacement-control includes means to trap a bath of lubricating liquid around the working parts of the pump, in the event that the discharge line from the pump should be ruptured.

-Pumps of this type are usually applied to air.- plane engines and ,in such case mustrun continuously. The variable volume or variable displacement controlgives smooth volumetric control from zero dischargeto fullcapacity. Pumps v4 omino (ol. ros-11s)- showlng the spill-back valves in the zero capacity position.

statements of direction used in thorouowmg description referto the pump positioned as in of this type are lubricated by the hydraulic liquid whichv is pumped, and many priorart p'u'mps would be destroyed if the discharge line or parts connected thereto were ruptured,.because the y pump lost its lubricating liquid, or even pumped itself dry. The' provision of automatic means which connects the lubricating bath to the pump circuit when the pump is operating normally and traps the lubricating bath upon loss of head pressure is consequently a'n important safeguard.

The volumetric control is exercised in response to head pressure by spill-back valves, one encircling each plunger externally to the cylinder, and controlling a port leading from-a point within the cylinder through the plunger to a point onl the plunger wholly external to the cylinder. This arrangement minimizes leakage and simpliiles design and manufacture. This volumetric control arrangement in its b road aspects forms the subject matter of my application Serial No.

632,975, filed December 5, 1945, now abandoned.A

The present application-is directed to features peculiar to multi-cylinder pumps, particularly those having the cylinders arranged in circular series, with their axes parallel.

The plungers work in a cylinder block and their outer ends are'guided in guideways formed in an adjacent guide block. This guide block is' so y charge. The relief valve discharges tothe sumpy Fig. l.

The housing of the pump comprises a body B and a cap 1. The cap has an inlet connection` l and a discharge connection 9 which take the form oi' tapped ports into which the suction and discharge pipes (not shown) are screwed. l

Clamped between a shoulder II in the body and a shoulder I2 in the cap is the cylinder assembly made up of a cylinder block I3 and a guide block Il. These are annular in form and enclose between them a chamber I5 which communicates with the inlet port i by way of a passage IIl formed in the cylinder block.

The outer periphery oi the cylinder block is is channeled to receive -a ring gasket I1 which seals the jointbetween the body B, can 1 and cylinder block I2. A ring gasket I8 seals the inner periphery of the cylinder block to the cap. In this way an( annular discharge channel I9 formed in cap 1 is isolated. It communicates with the discharge connection 9 through passage 2I.

The cylinder block" is bored through to' form the cylinders 22 and the discharge valves 22 are cup-shaped, and are seated by coil compression' springs 24 against the outer face of the cylinder block. They are guided in pockets bored in the cap 1, as shown.

`The small spring loaded relief valve 25 leading from discharge connection 9 is so adjusted that it will open at a pressure slightly lower than that which will set the capacity control for zero disfrom which' the pump draws the oil which it formed as to afford a chamber in which the spillback valves and a part of the mechanism for shifting them in unison are housed.

A preferred embodiment will now be described by reference tp the accompanying drawings, in which:

Fig. 1 is o longitudinal axial sootion of o nine cylinder pump embodying the invention.

Fig. 2 is an exploded .view of the capacity a'djusting motor.

Fig. 3 is a section on the line 3--3 of Fig. l.

Fig. 4 is a view similar toa portion of Fig. 1

pumps. The function oi the relief valve is to open just before the pump reaches zero capacity setting and thus assure that the pump will dis-V charge at least a small quantity of oil so long as the discharge line is intact. 'I'he quantity of oil so circulated is the minimum necessary to cool the pump when operating against the established head pressure.

The intake ports for the cylinders 22 are grooves 26, one in each cylinder, each connected with inlet 8 by apassage 21 drilled in the cylinder block I3. The guide block Il has bores alined with the cylinders 22 'and of the same spring 54.

alleanza ber I5 and into its cylinder 22. The lower plunger 23 in Fig. 1 is in its fully retracted position in which its end is between the margins of groove 23. The upper plunger 29 in Fig. 1 is in the fully advanced position in which it is substantially in contact with its discharge valve 23.

The plungers are retracted by coil compression springs 3l reacting between block I4 and flanges on the outer ends of respective plungers. Each plunger carries a universally tiltable thrust head 32.

The drive shaft 33 is counterbored at 34 from its inner end, the counterbore opening into chamber I5. Keyed to shaft 33 is a swash plate 35, which actuates the plungers 23 through an interposed annular creep plate 36. The swash plate 35 has a hub 31 which turns in bearing bushing 36 mounted in a ring 39. 'I'he ring 33 is confined in a seat formed for it in body 6 and sustains the swash plate 35 against axial thrust by means of a creep ring 4I.

A radial port 42 leads through the swash plate 36 from counterbore .34. It acts to draw oil through passage I6, chamber I5, and counterbore 34 by centrifugal action, and keep the cam mechanism and plunger ends submerged in oil. The assembly generally indicated at 43 is a shaft seal (for which per se no novelty is here claimed). The function of the seal is merely to prevent oil from leaking out around the shaft. The part 44 is merely the conventional splined driving head for shaft 33.

Except for the guide block I4, chamber I5 and relief valve 25, the pump, as so far described resembles that described and claimed in my Patent No. 2,381,056, dated August 7, 1945.

Pressed into the central aperture of the annular cylinder block I3 is a bushing 45 which forms the cylinder of the pressure control motor. At its left end it is bored to fit stem 46. At its right hand end it is concentrically bored to fit the slightly larger piston sleeve 41. These are lapped fits.

The piston sleeve 41 fits freely on a reduced portion of stem 46 on which it is retained by nut 48, and to which it is sealed by a, ring gasket 43 confined in a telescopingl annular pocket, as shown. In this way the piston sleeve may have slight lateral motion to accommodate itself t possible eccentricity between the bore and counterbore in cylinder bushing 45.

At midlength the bore of cylinder bushing 45 is relieved or enlarged, and to this enlarged portion a port I leads from an encircling groove. To this groove a port 52 (shown in dotted lines in Fig. l) leads from discharge channel I3.

Stem 46 and its piston 41 are spring biased to the left. Since the effective area of the piston is merely the annular area of the shoulder offered by the difference in diameter between sleeve 41 and stem 46, the springs need not be heavy. It is, however, desirable that the springs be long to permit relatively long travel of stem 46 without marked increase in the spring stress, a condition imposed by the desire to control within a narrow fluid pressure range.

To secure long springs in limited length, 'two telescopically arranged tandem springs are used. A cuplike flanged spring seat 53 fits over nut 43 and sustains the left end of coil compression A cup-shaped flanged spring seat 55 fits over the left end of coil compression springBB and sustains the right end oi spring 54. A bolt 51 limits separation of the spring seats 53 and 55. The right end of spring 56 is 4 sustained by adjustablev spring seat 58 guided in fitting 59 which is screwed into cap 1 and sealed with a gasket as shown. Seat 53 is adinstable by turning thrust screw 6I. Leakage around the screw is prevented by ring gasket 62 and the adjustment is locked by acorn nut 63.

Stem 46 carries a plate 64 which has two functions. When stem 46 is at its leftmost position (assumed when the discharge line is ruptured), it seals at 65 on block I4 and by closing off the counterbored end of shaft 33 traps a charge of oil around the swash plate and plunger ends. This is an ancillary function.

The main function of plate 64 is to adjust the position of spill-back valves 66, one for each plunger 29.

The valves are sleeves through each of which a corresponding plunger works. Each valve is received in a notch in the periphery of the plate 64 and has flanges 61 which straddle the plate. Each valve controls a groove 68 in the periphery of the plunger. To this groove an axial passage 66 and cross-bores 1I lead from the interior of cylinder 22.

When the valves 65 areat the extreme lefthand position shown in Fig. 1 they blank grooves 68 j ust before the end of the related plunger overtravels groove 26 in its cylinder. These events become simultaneous when normal discharge pressure is approached. As discharge pressure rises through the control range (between normal minimum and maximum, a spread of say 200 pounds per square inch) the valves are moved further and further to the right until at the maximum they reach the positions -indicated in Fig. 4 in which the spill-back ports 68 are open throughout the working stroke. The relief valve 25 is set to open just before the maximum discharge pressure is reached.

In the pump as shown and above described, the spill-back occurs during the initial portion of the discharge stroke and this is considered preferable because the spill-back flow starts as cylinder pressure develops.

It is possible however to relocate the grooves 61, and position the valves so that their righthand faces instead of their lefthand faces perform the control function and the spill-back occurs in the terminal portion of the discharge stroke. In such case the valves are at the right in full capacity setting, blank the spill-back` ports in the initial part of the stroke and are overtraveled in the latter part,I and hence must be moved to the left to reduce pump capacity. This entails a reversal of the direction of action of the pressure responsive motor and its springs.

It is not deemed necessary to illustrate this alternative arrangement of the same functional parts, a mere reversal of arrangement without significant change of function being all that is involved. Such an arrangement is within the ambit of at least the broader claims.

an intake passage leads means engaging saidbloc'ks to maintain "alinement of the guide ways and bores; .a divided housing formed to enclose and confine said blocks in assembled relation; a shaft bearing centered in the guide blczk: thrust and radial shaft bearings supported the housing, and axially allned with the bearing in the guide block; a rotary drive shaft' moun ed to turn in said' bearings; a.

cam carried by sai shaft; 'aplurality of plungers, each extendingthrough 'a guide in the guide block across said chamber and into a corresponding cylinder bore, said piunge'rs being arranged to be reciprocated byisaid cam, and each plunger having a spill-back port leading from thecorresponding cylinder bore to a point on the plunger within said chamber; spill-back valves, one encircling each plunger within said chamber and each controlling flow through its spill-back port; a pressure motor mounted at the center of the cylinder block,subject todis'charge` pressure developed by said pump and arranged to shift said spill-back valves in unison; yielding loading means for said motor; vand valve means controlling inlet and discharge to and from each cylinder bore.

2. The combination deiined in claim 1 in which the housing affords a cam-enclosing space between the bearing in the guide block and the thrust and radial bearings, in which space the 30 cam is located, and the shaft and guide block isolate said cam enclosing space from said chamber except for a passage which leads from the chamber axially through the shaft and thence throughlone ofthe V approimaftelyradillythroughthecam slid `cam-#enclosing space.

3. The combination defined in claim 1 in which the housing affords a cam-enclosing space lac-y tween the bearing in the guide block and their thrust and radial bearings, in which space the cam is located, andthe shaft and guide block uisolate said cam-enclosing space from said chamberexcept fora passage which leads from the chamber axially through the shaft and thence approximately radially through the cam into said `cam-enclosingl space, and the connection between the motor and the vspill-baci: valves includes a` part which obstructs said passage through the shaft when the spill-back' valves are set in one of their two extreme positions.

4. The combination defined in claim 1 in which `the divided housing comprises a body and a cap,

the body enclosing the cam mechanism and lateral portions ofthe guide block and cylinder block, and the cap overlying and engaging the cylinder block; and the yielding loading means is sustained -by said cap.

MATTHEW W. HUBER.

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

UNITED STATES PATENTS Number Name y Date l2,142,086 Alden Jan. 3, 1939 2,385,990 Huber. e Oct. 2, 1945 Y Lum ---s -4-4- Jan. 22, 41948

Images