US2455289A - Fuel injection pump - Google Patents

Description

Nov., 30, E948. G. w. BAlERLElN FUEL INJECTION Puur Filed Feb. 27, 21.945A

2 Smets-Sheet l P R w m n AC w m w m Nw.. m.

2 Sheets-Sheet 2 Filed Feb. 27, 1946 Fuga AGENT A Patented lNov. 30, 'i

, anni. INJECTION rum George W. Baierlein, SpringiielmMass., asslgnor, by mesne assignments, to Niles-Bement-Pond Company, West Hartior of New Jersey d, Conn., a corporation Application February 27, 1946, Serial No. 650,408

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 rplurality 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 oi the present invention is .to provide an improved fuel injection pump mechanism including an improved thrust bearing arrangement for carrying loads due to the pressures built up .by the pum-p plungers. f

A further object is -to -provide such an arrangement wherein the number and sizeof 'the thrust carrying parts a-re minimized, so that a lig'ht, relatively weak metal, for example, aluminum, may be used for the lightly stressed and unstressed parts of the pump structure. l

Another'object of the present invention is to provide improved mechanism for varying simul taneously the delivery of all the -plungers in a multiple plunger pump.

Another object is to provide improved mechanism for adjustingindividually the delivery' of each or the pump plungers.

A lfurther object is to provide such individual adjusting mechanism which is readily accessible while the pump is mounted on an engine.

A further object of the invention is to provide an improved wobble plate structure for reci-procating the plungers in a pump where the plungers are arranged circumferentially of a cylindrical body.

A further object 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 p Figure 1 is a view, partly in cross-section, of a multiple plunger fuel injection pump embodying my invention,

Figure 2 is an elevational view, `also partly in section, of the same pump, taken at right angles lto the View in Figure 1,

Figure 3 is aplan view of apart of the plunger adjusting mechanism, and

5 Claims. (CL 10S-173) a pump mechanism consisting of a mounting plate I0, which is provided with a flange I2, hav.- ing holes4 Il bored thru 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 I8 (Figure 2), to the mounting plate I0. A drive shaft is carried in the plate l0 by a combined radial and thrust ball bearing 22 and by a needle bearing 24-in thebody I8.

Figure 4 is an elevational view of the part v shown in Figure 3, rotated thru 90 from the position of Figure 3.

Referring now to the drawings, there is shown On the lower side, as it appears in the drawings, of the body I6, the shaft 20 carries,thru a combined thrust and radial bearing 28, a wobble plate 28. The wobble plate 28 actuates, thru. mechanism to -be described in detail below, a plurality of pump plungers y3|), which reciprocate in barrels 82 received in bores, 34 thru the housing i6. A cover 36 is provided -for the pump. rlfhis cover is attached, by means of bolts 38 and dowel pins 40 (Figure 2) to the pump body I6.

vThe end of lpump barrel 32 nearest the plate I0 is closed by a valve seat member 42. This seat y member is rprovided with a .passage thru its central portion, and a valve 44 engages the face of the seat member on the side opposite t'hebarrel 82., A spring 46 biases the valve 44 to closed position. The spring 48 is held by a retainer 48 threaded into the plate i0. Washers 50 and 52 and a spacer 54 separate the rim of the retainer 48 from the rim of seat member 42. When the retainer 48 is threaded in place, it holds the washers 50 and 52, the spacer 54, the seat member 42, and the barrel 32 in assembled relation,

forcing a shoulder 56 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 which opens into the' bolt holes 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 35, carried by thebody i8 engages the recess33 and holds the barrel against rotation in the body f6, so :that the calibration of the pump cannot be disturbed by any change in the angular position of port |34.

The outer race of bearing 22 is press-fitted into the plate I0. The inner race is held against a shoulder'on the shaft 20 by a lock nut 62 and a lock washer 84. It may be seen that the thrust forces on the bearing 22 are such as to tend to move the shaft 20 downwardly thru the plate i 0.

3 l Therefore these thrust forces tend to,.hold the outer race of bearing 22 more ilrmly in its seat. The inner race of bearing 26 is held,in .place against a shoulder on shaft 28 by a lock nut 86 and a lock washer 68. A timing disc 18 is clamped face with a. groove 88, wide and deep enough to receive the balls 18. The groove 88 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. passed thru the slot during assembly. Each of the slots 8'6 opens into a generally circular aperture 88, which allows for the wobbling 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 98 and 92, which are received with the yball in the groove 80. The upper shoe 98 is provided with a suitable central aperture to permit passage of the push rod 16 therethru. It may be seen that as the shaft 28 rotates a wobbling motion "is imparted to the plate 28 so that the plungers 38 and push rods 16 are sequentially reciprocated. It may also be seen that the thrust forces acting parallel to the shaft 28, due to thel fluid pressures built up by the plungers. are all carried by the plungers 30.

. 4 Y face of the push rod 18, so that the sleeve 94 and the push rod 16 and the plunger 38 rotate together. When the screw i I8 is loosened, it is possible to rotate the push rod 16 within the sleeve 84 without rotating the latter. The sleeve 94 is provided with a pair ofupwardly extending projections 2 which mate with corresponding projections ||4 on a sleeve ||6 which surrounds the barrel 32. The sleeve 6 carries a pinion gear I I8 having teeth over at least a 90 sector thereof, All of the pinion gears H8 engage a central ring gear |28 carried on a projecting hub portion of casing, with 'a bevel gear sector |22.

the pump body I6. The toothed portions of the pinion gears H8 all face inwardly so as to engage the ring gear |28.

One of the sleeves ||6 is 4also provided, on the portion of its periphery nearest the outside of the 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 i6. Outside the body I6, the .control shaft |26 is splined, as shown at |38 and thereby provided with means by which it may be rotated from the outside of the pump unit.

Each of the pump plungers is provided with'a i helical scroll |32 of generally conventional form,

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 I8. The body i6 is xeri at one end to the mounting plate i0. No other part of the body I6 is attached to any fixed part of the engine.

Thrust forces reaching the plate i8 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 |16 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 also contributes to the reduction of the weight'of my oumpingmechanism.

Each plunger 38, carries a sleeve 94, whose structure is shown in detail` in Figures 3 and 4.

The sleeve 94 consists of a generally tubular portion 96. The portion 96 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 |08, which separates that portion of sleeve 96 into two fingers |82, |84. These two ngers are provided at their free ends with lugs |86, |88. A tapered screw H8 is provided'for joining the .two lugs. It may be seen that upontightening of the screw I |8 the two iingers |82 and |84 are tightly clamped on the surwhich cooperates with an inlet port |34. When the port |34 is closed by the scroll |32, then the plunger is actively pumping fuel thru the discharge valve 44. Each plunger is also provided, below the scroll |32, with a circumferential groove |33. A's 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 vtakes place may be 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 H8 to be rotated ahd this motion is transmitted thru the ring gear |28 to all the other pinion gears. If it is desired to adjust the' delivery per stroke of one of the plungers, without aecting the others, it is only necessary to remove the cover 316 whereupon the claniping screws ||8 associated with all the plungers become accessible.

The timing disc 18 cooperates with a timing pin |36 so that it is possible to determine the angular position of the pump shaft from the outside of the casing. The periphery of the disc 18 is slotted as shown at |38. The timing pin |36 is mounted in a cup |48 carried by the cover 36. A spring |42 in the cup,|48 biases the pin to then position shown in Figure 1 where it does not engage the slot |38 or the timing dise 48. 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 28 for timing the pump to the engine, the cover |44 is removed and `the pin |36 is depressed and j held in. The shaft 28 may then be slowly rotated by hand until the pin is felt to drop into the' slot |38. The slot |38 is located vin the timing disc 18 so that its angular position corresponds to the end of delivery by the pump plunger serving cylinder No. 1 of the engine.

The driving end of shaft. 29 is driven thru an intermediate drive member |46, which corrects for misa-lignment between the pump shaft 28 and the engine drive shaft.

The shaft |26, outside the body I6 may be proademas vided with a suitable pointer |50 cooperating with a scale |52, to indicate the pump delivery setting.

Fuel is supplied to the pump thru an inlet connection |55 which leads to a chamber I 59-surrounding all the barrels 32 at a point near their inlet ports |30.

Oil is supplied under pressure thru a connection indicated generally at 58 to the chamber |99 formed between the cover |56 and the pump body I5. The oil flows from the chamber |50 thru a check valve |52 and thence out thru the hollow center of the shaft |20. This lubricating system is completely shown and claimed in the co-pe-nding application of Milton E. Chandler, Seria1 No. 609,350, led August 7, 1945, which issued on July 1, 1947, as Patent Number.2,423,373, and forms no part of the present invention.

The terms and expressions which I have einployed are used as terms of description and not of limitation, and I have no intention. in the use of, such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of th invention claimed.

I claim as by invention: i

l 1. Injector pump mechanism, comprising a generally cylindrical housing including a supporting portion and a body portion, said body portion having a pluralityof bores -therethru parallel to the axis of said housing, a plurality of plungers, one plunger being reciprocable lin each of said bores, the end-s of said bores nearest said` supportingportion being provided with discharge ports, a drive shaft extending coaxially thru both portionsy of said housing, means attached to said drive shaft beyond the side of said lbody portion opposite said supporting portion for reciprocating said plungers, first thrust bearing means associated with said reciprocating means for transmitting to said shaft axial forces due to reciprocation of said plungers, Vand second thrust bearing means between said shaft and said supporting portion for transmitting axial forces from said shaft to said supporting portion. A

2. Injector pump mechanism, comprising a generally cylindrical housing including a mounting plate and a body attached thereto, said body having a plurality of bores extending therethru from. said plate parallel to the axis of said housing, a plurality of plungers, one plunger being reciprocable in each of said bores, a drive shaft extending coaxially thru said plate and body, means tached to said drive shaft at the end of said body opposite said plate for reciprocating said plungers, first thrust bearing means associated with said reciprocating means for transmitting to said shaft axial forces due to reciprocation of 3. Injector pump mechanism, comprising a generally cylindrical housing including a mounting plate of relatively heavy, strong material and a body attached to said plate and formed or a in each of said bores, a drive shaft extending coaxially thru said plate and body, means attached to said drive shaft at the end of said body opposite said plate for reciprocating said plungers, first thrust bearing means associated with said reciprocating means for transmitting to said shaft axiai forces due to reciprocation of said plungers, and second thrust bearing meansbetween said shaft and said plate f-or transmitting axial forces from said shaft to said plate, so that the -thrust forces due .to reciprocation of said plungers Iare transmitted to the relatively strong plate and not .to the relatively light body.

4. Injector pump mechanism, comprising a generally cylindrical' housing including a mounting plate and a body attached thereto, said body having a plurality of bores extending therethru from said plate parallel to the axis of said housing, said plate having bores alined with said lbody bores, a barrel lining each pair of alined bores from a point within said plate to the other end of said body, plug means in said plate for the end of each barrel, a plurality of plungers, one plunger being reciprocable in each of said barrels, a drive shaft extending coaxially thru bothsaid plate and body, means att-ached to said drive shaft at the end of said body opposite said plate for reciproeating said plungers, first thrust bearing means associated with said reciprocating means for ciprocation of said plungers, and second thrust bearing means between said shaft and said mounting plate for transmitting axial forces from said shaft to said plate.

5. InJector pump mechanism. comprising a generally cylindrical housing including a supportting portion 'and a body portion. said -body .portion having a'plurallty of bores therethru parallel to the axis of said housing. a plurality of plungers, one plunger being reciprocable in each of said bores, the ends of said bores nearest said supporting portion 'being provided with discharge ports,

-a drive shaft extending coaxially thru both portions of said housing, means attached to said drive shaft beyond the side of said body portion opposite said supporting portion for reciprocating said plungers, first thrust. bearing means associated with said reciprocating means for transmitting to said shaft axial forces due to reciprocation of said plungers, said supporting portion having a central recess in the side opposite said body portion, and second thrust .bearing means for said v shaft located in said recess for transmitting axial relatively light material, said body having a plurallty of bores extending therethru from said plate parallel to the axis of said housing, a plurality of plungers, one plunger being reciprocable 'lo forces from said shaft to said supporting portion.

GEORGE W. lBAIltliLIEIN.

REERENCES CITED The following references are of record in the ille of this patent:

UNrrED s'ra'ras PATENTS Name Date Richer Jan. 28, 1932 Heder May 30, 1939 Ditto Sept. 24, 1940 Bremser Nov. 9, 1943 Beeh et al. July 31, 1945 Beeh Nov. 6, 1945 Joy Ma 14, 1948 OID- lulli- J 1,

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