US2455290A - Discharge valve assembly for fuel injector pumps - Google Patents

Description

:claw

G. W. BAIERLEIN DISCHARGE VALVE ASSEMBLY FOR FUEL INJECTOR PUMPS original Filed Feb. 27,l 194s Nov. 3G, 1948.

Patented Nov.r 30,l 1948 DISCHARGE VALVE ASSEMBLY FOR FUEL INJECTOB PUMPS George W. Baierlein, Springfieid,-Mass.,

assigner to Niles-Bement-Pond Company, West Hartford, Conn., a corporation oi' New Jersey original application Februar-62.*?, 194s, serial No.

650,408. Divided and this application February 6, 1947, Serial No. 726,846. v

The present application is a division of my application Serial No. 650,408, illed February 27, 1946.

The present invention relates to fuel injection pumps for internal combustion engines. Certain of 'the features of the invention are of particular utility in connection with a pump for a multiple cylinder engine having a plurality of pump plungers, one for each cylinder. Other features of the invention are of especial utility in connection with an injection pump adapted for use on an aircraft engine, wherein light weight is very important.

An object of the present invention is to provide an improved pump barrel and discharge valve assembly for use in a pump of the type described:

Other objects and advantages of the present invention will become apparent from a consideration of the appended specification, claims and drawings, in which The figure is a view, partly in cross-section, of a multiple plunger fuel injection pump and embodying my invention.

Referring now to the drawings, there is shown a pump mechanism consisting of a mounting plate I8, which is provided with a iange l2, having holes I4 bored through it to receive bolts (not shown) so that it may be mounted on a suitable pad provided on an internal combustion engine. A pump body I6 is attached, by any suitable means such as dowel studs, (not shown), to the mounting plate I0. A drive shaft 28 is carried in the plate I by a combined radial and thrust ball bearing 22 and by a needle bearing 24 in the body I6.

On the lower side, as it appears in the drawings, of the body I6, the shaft 28 carries, thru a combined thrust and radial bearing 26, a wobble plate 28. The wobble plate 28 actuates, thru mechanism to be described in detail.below,.a plurality of pump plungers 30, which reciprocate in barrels 32 received in bores 24 thru the housing I6. A cover 36 is provided for the pump. This cover is attached, by means of bolts and dowel pins (not shown) to the pump body I6.

'I'he end of pump barrel 32 nearest the plate I0 is closed by a valve seat member 42. This seat member is provided with a passage thru its central portion, and a valve 44 engages the face of the seat member on the side opposite the barrel 32. A spring 46 biases the valve 44 to closed position. The spring 46 is held by a retainer 48 threaded into the plate I8. and a spacer 54 separate the -rim of the retainer 48 from the rim of seat member 42. When the Washers 56 and 52- 2 Claims. (Cl. 103-l54) with a suitable central aperture to retainer 48 is threaded in place, it holds the washers 56 and 62, the spacer 54, the seat member 42, and the barrel 32 in assembled relation, forcing a shoulder 58 on the barrel 32 up against a corresponding shoulder in the pump body I6- The spacer 52 is provided with lateral outlet passages 58, leading to a drilled passage 68 which opens into the bolt hole I4. From there the fuel discharged by the pump may be conveyed thru a hollow bolt, in a well-known manner, to one of the cylinders of the engine.

The outer'surface of each of the barrels 32 is provided with a recess 33., A set screw 85, carried by the body I6 engages the recess 88 and holds the barrel against rotation in the body I6, so that the calibration of the pump cannot be disturbed by any change in the angular position of port |34. v

The outer race of bearing 22 is press-fitted into the plate I6. The inner race is held against a shoulder on the shaft 28 by a lock nut 62 and a lock washer 64. It may be seen that the thrust forces on the bearing 22 are suchas to tend to move the shaft 2U downwardly thru the plate l 8. Therbefore these-thrust-forces tend to hold the outer` race of bearing 22 more rmly in its seat.

The inner race of bearing 26 is held in place against a shoulder on shaft 20 by a lock nut 66 and a lock washer 68. A timing disc 18 is clamped between the lock washer 68 and the inner race of bearing 26. The purpose of the timing disc 10 will be later described. The outer race vof the bearing 26 isretained in the -wobble plate 28 by a retaining ring 12, which may be of the wellknown snap ring type.

Each of `the plungers 30 is connected by means of a shear pin 14 to aV push rod 16. The lower end of push rod 16 terminates in a ball 18. The wobble plate 28 is provided on its peripheral surface with a groove 80, Wide and deep enough to receive the balls 18. The groove separates an upper, as it appears in the drawing, flange 82 on the wobble plate from a lower ange 84. The upper flange 82 has its'outer edge slotted, as at 86, so that the push 'rods 16 may be lpassed thru the slot during assembly. Each of the slots 86 opens into a generally circular aperture 88, which allows for the wobbllng motion of the wobble plate 28 with respect to the'push rods 16. Each of the balls 18 rides in a pair of upper and lower shoes 90 and 92, which are received with the ball in the groove 80. The upper shoe 96 is provided permit passage of the push rod 16 therethru. It may be seen that as the shaft 20 rotates a wobbling moers 30 and push rods 18 are sequentially reciprocated. It may also be seen that the thrust forces acting parallel to the shaft 20, due to the iiuid pressures built up by the plungers, are all carried by the plungers 30, the associated structure which connects the plungers to the wobble plate, the` wobble plate 28, and shaft 20 to the bearing 22 and the mounting plate I0. The body i6 is fixed at one end to the mounting plate |0. No other part oi the body I6 is attached to any xed part of the engine. Thrust forces reaching the plate I are not transmitted thru the body I6, because there can be no opposing reactive force. Hence the body i6 cannot be stressed by such thrust forces. Therefore, it is possible to build the body I6 of a light, relatively weak metal such as aluminum, while^the parts subject to' stress are made of stronger metal, such as steel. In this way it has been found possible to substantially reduce the weight of the multiple pump unit. Where .such a pump unit is intended for use in an aircraft, such a reduction in weight is tremendously important. It should be noted that the flange 82, which transmits thrust to the plungers on their intake strokes, is made lighter than the flange 84, which transmits thrust to the plungers on their pumping strokes. This difference in the thickness of the two iianges also contributes to the reduction of the weight of my pumping mechanism.

Each plunger 30, carries a sleeve 94, which includes a generally tubular portion 96. The portion 86 is slotted'as shown at 98 from one side laterally across for a distance of more than half its diameter. The part of the sleeve 94 below the slot 98 is provided with a longitudinal slot as shown at |00, which separates t t portion of sleeve 96 into two iingers which a e provided at their free ends with lugs |06, |08 respectively.

A tapered screw i|0 is provided for joining the two lugs. It may be seen that upon tightening of the screw H0, lugs |06 and |08 are drawn together and nthe two iingers are tightly clamped on the surface of the push rod 16, so that the sleeve 94 and the push rod 16. and the plunger 30 rotate together. When the screw ||0 is loosened, it is possible to rotate the push rod 16 within the sleeve 94 without rotating the latter. sleeve 94 is provided with a pair of upwardly extending projections ||2 which mate with corresponding projections ||4 on a sleeve l|6 which surrounds the barrel 32. The sleeve ||6 carries a pinion gear ||8 having teeth over at least a 90 sector thereof. All of the pinion gears ||8 engage a central ring gear carried on a projection hub portion of the pump body |'6. The toothed portions of the pinion gears ||8 all face inwardly so as to engage the ring gear |20.

One of the sleeves ||6 is also provided, on the portion of its periphery nearest the outside of the casing, with a bevel gear sector |22. This engages with another bevel gear sector |24 carried by a control shaft |26 mounted in a suitable hub |28, which is carried by the pump body |6. Out-side the body |6, the control shaft |26 is splined, as shown at |30 and thereby provided with means by which it may be rotated from the outside of the pump unit. f

Each of the pump plungers is provided with a helical scroll |32 of generally conventional form, which cooperates with aninlet port |34. When the port |34 is closed by the scroll |32, then the plunger is actively pumping fuel thru the dis- The' charge valve 44.Y Each plunger is also provided. below the scroll |32, with a circumferential groove |33. As soon as the port |34 is uncovered by the upper edge of groove |33, then the pressure ahead of the plunger is relieved and pumping ceases. By rotating the plunger on its own axis, the length of the period during which pumping takes place may he varied, thereby varying the fuel delivery per stroke of the pump plunger. By operation of the control shaft |26, all the plungers may be simultaneously rotated. Rotation of control `shaft |26 causes one pinion gear H0 to be rotated and this motion is transmitted thru the ring gear |20 to all the other pinion gears. If it is desired to adiust the delivery per stroke oi one of the plungers, without aiiecting the others, it is only necessary to remove the cover 36 whereupon the clamping screws ||0 associated with all the plungers become accessible.

The timing disc 10 cooperates with a timing pin |36 s o that it ispossible to determine the angular position of the pump shaft from the outside of the casing. The periphery of the disc l0 is slotted as shown at |38. The timing pin |36 is mounted in a cup |40 carried by the cover 36. A spring |42 in the cup |40 biases the pin to the position shown in the drawing where it does not engage the slot |38 or the timing disc 40. A cover |44 is provided for the outer end of the timing pin so that it will not be accidentally pushed in while the pump is in operation. When it is desired to determine the angular position of shaft 20 for timing the pump to the engine, the cover |44 is removed and the pin |36 is depressed and held in. The shaft 20 may then be slowly rotated by hand until the pin is felt to drop into the yslot |38. The slot |38 is located in the timing disc 10 so that its angular position corresponds to the end of delivery by the pump plunger serving cylinder No. 1 ci the engine.

The driving end of shaft 20 is driven thru an intermediate drive member |46, which corrects for misalignment between the pump shaft 20 and the engine drive shaft. 1

The shaft |26, outside the body I6 may be provided with a suitable pointer |60 cooperating with a scale |62L to indicate the pump delivery setting.

Fuel is supplied to the pump thru an inlet connection (not shown) which leads to a chamber |56 surrounding all the barrels 32 at a point near their inlet ports |34.

Oil is supplied under pressure through a connection (not shown) to the chamber |60 formed between the cover |56 and the pump body ||6. The oil ows from the chamber |60 thru a check valve |62 and thence out thru the hollow center of the shaft 20. This lubricating system is completely shown and claimed in the copending application of Milton E. Chandler, Serial No. 609,350, iiled August '7, 1945, which has mashoulder on said body within said bore. a barrel receivable in said bore and having a shoulder l adapted toengage the shoulder` in said bore, a

recess in an external face of said barrel, a set screw insertable thru said body to engage said recess and hold said barrel against rotation, a plunger reciprocable in said barrel, a discharge valve seat member in said bore engaging the end of said barrel, a valve member engaging the face of said seat member opposite said barrel, hollow spacer means in said bore engaging said seat and surrounding said valve, a spring retainer threadedly inserted in said bore and engaging said spacer means to hold said spacer means, said seat member and said barrel in assembled relation, and a spring within said spacer and retained by saidretainer and biasing said valve to closed position, said spacer being laterally apertured to permit outow of iuid passed by said valve.

2. Injection pump mechanism, comprising a generally cylindrical housing including a mounting plate and a body attached to said plate, said body having a plurality of bores extending therethru from said plate parallel to the axis ciy said housing, a shoulder on said body within each said bore, said plate having a plurality of bores alined with the bores in said body, a barrel receivable in each said bore and having a shoulder adapted to engage the shoulder in said bore, said barrels being longer than said body so as to extend within said plate when said shoulders are in engagement, a recess in an external face of each said barrel, a set screw insertable thru said body to engage said recess and hold said barrel against rotation, a plunger reciprocable in each said barrel, a discharge valve seat member in each of said. plate bores engaging the end of said barrel, a valve member engaging the face of said seat member opposite said barrel, hollow spacer means in each said plate bore engaging said seat and surrounding said valve, a spring retainer threadedly inserted in each said plate bore and engaging said spacer means to hold said spacer means, said seat member and said barrel in assembled relation. and a spring within said spacer and retained by said retainer and biasing said valve to closed position, saidv spacer and plate being laterally apertured to permit outflow of iiuid passed by said valve.

GEORGE w. BAIERLEINQ REFERENCES crrsn The following references are of record in the file of this patent:

UNITED STATES A'rENTs

Images