US2195552A

US2195552A - Heavy duty piston

Info

Publication number: US2195552A
Application number: US155310A
Authority: US
Inventors: Alexander M Alexandrescu
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-07-23
Filing date: 1937-07-23
Publication date: 1940-04-02
Anticipated expiration: 1957-04-02

Description

April 2, 1940. A. M. ALExANDREscU 2,195,552

HEAVY DUTY PISTON Original Filed July 23, 1937 3 Sheets-Sheet 1 Bnventor da. M. uzZaza/miras'cw Gttornegs'.

April 2, 1940. A. M. ALExANDRl-:Ascu

HEAVY DUTY PIsToNA Original Filed July 23, 1937 3 Sheets-Sheet 2 April 2, 1940. A. M. ALEXANDRESCU 2,195,552

HEAVY DUTY PISTON y original Filed July 2s, 1957 s sheets-sheet s a Z0 30 z3 10 40 Vr Z5 39 34 4537 y up 153 42 Jil@ 41 36' 929 l F 22 Z3 y 2f y v :inventor 1f?. M lfwandrescw Patented Apr. 2, 194D errno STATES PATENT. OFFICE 2,195,552 nEAvY DUTY Prs'roN .Alexander M. Alexandrescu, Cleveland, Ohio Application July 2s, 1937, serial No. 155,310

Renewed February 5,

' s claims..

An object of the invention is to provide a piston having ribs therein subserving two funcf tions: first, to reinforce and strengthen the piston, its ring column, .head and skirt; and secondly, to transfer and dissipate the heat rapidly from the shell or wall and top of the piston, to the end that neither the piston, nor the-engine generally, will become overheated or heated beyond desirable Working temperature; thereby effecting economy in the operation of such engines accompanied by conservation of the life of the working parts of the engine.

Another object of the invention is to provide the ribs in continuity from the top of the piston down the side wall thereof and down to the bottom open portion of the piston whereby to carry off the heat as rapidly as possible and as uniformly as practicable, avoiding any sharp rises or declinesin temperature in the piston wall or top.

A further object of the invention is to provide, by the use of the ribs, for additional strength within thehollow piston at the diametrically opposite points requiring such strength, namely at right angles to the axis of the wrist pin. It is understood that there is a tendency of the piston to slap in a plane at substantially right angles to the wrist pin owing to the action of the connecting rod upon the Wrist pin. This portion of the piston tends to greatest wear and to greatest distortion and it is a purpose of the invention to reinforce and strengthen the piston particularly and peculiarly at these points in order that such distortion may be minimized.

With the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto.

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views.

Figure 1 is a front elevation of an improved heavy duty piston constructed in accordance with the present invention and with parts shown broken away and in section.

Figure 2 is a vertical section taken on the line 2--2 in Figure' 1.

l ure 2 the group angles'to the axis of the wrist pin.

Figure 3 is a vertical-section taken at right angles to Figure 2 on the line 3-3 thereof.

Figure 4 is a horizontalsection taken on the Y line -t in Figure 2.-

Figure 5 is a similar section 5-5 in Figure2.

Figure 6 is also a horizontal section taken on taken on the line the line G--B, likewise in Figure 2.

Figure l is a fragmentary enlarged vertical section taken through one boss of the piston and.'l

showing the wrist pin and its method ofv connection to the boss.

Figure 8 is a vertical section taken on the line 88 in Figure 7, and

Figuref9 is a vertical section 9-9 in Figure 1.

Referring more particularly to the drawings, i0 designates generally a cylinder in which the improved heavy duty piston reciprooates. The

taken on the line top of the piston is designated generally at ll,

the ring column at l2 and the piston skirt at i3. In the top of the piston there may be a cavity lll exposed on its upper side for two purposes. This cavity increases the size of the compression and combustion'chambers. It also increases the length of the top wall il of the piston owing to the fact that, in the production of .this cavity Hl, the top wall l l is made partly spherical with its underside l5 presenting a convex surface.

` The greater the length, or the greater the area or the greater the amount of material in the top wall ll, the greater will be the capacity of this top wall to absorb and carry off heat unit from the piston and from the engine generally. While the invention derives great benefit from the use of such a spherical or curved piston wall Il, particularly in combination with the ribs as hereinafter described, this particular form of top wall is not essential to the invention.

The convex lower side l5 of the top wall is intersected by 4groups of ribs lland ll. In Figthree such ribs spaced apart from one another an appreciable distance and spaced appreciably from the side walls of the ring column I2 at right Looking at Figure 3 it will be seen that these ribs I6 extend from one side of the piston t0 the other and that at their ends they join with substantially vertical ribs I8. These vertical ribs have their outer edges preferably cast in one piece with the ring column. At their lower ends these vertical ribs I8 merge with bosses i9 in which the wrist pin is'v journaled.

Returning to Figure 2 it will be seen that I6 of ribs is shown to comprise these vertical ribs I8 are intersected by a horizontal annular rib 28. At the points of intersection the vertical ribs I8 are joined with the horizontal annular rib 20 thus making for a strong construction and also adding considerable densities of metal which will absorb the heat and transmit the same both downwardly through the vertical ribs I8 and about the piston through the horizontal annular rib 20. At their lower portions the vertical ribs I8 are all merged with solid blocks 2I which in turn are directly merged with the bosses I9. As shown in Figure 2 the blocks 2| and the bosses I9 are both merged with conduction bands 22 extending horizontally for distances around the circumference of the skirt I3.

Similar bands 23 extend about the lower portion of the skirt I3. These bands 23 like the bands 22 may be two in number as shown in Figure 6 and they extend part-way around the piston at the end portions of the wrist pin. The bands 23 are at the lower side of the bosses I9; whereas the bands 22 are at the upper side of such bosses.

As shown in Figures 2 and 5 there are intermediate ns 24 extending in opposite circumfer` ential directions from middle portions of the bosses I9. These fins, as shown in Figure 2, are spaced below the bands 22 and spaced above the bands 23. Thus there is ample space between the various conducting parts to permit of the rapid conductivity of the heat from oiT the metal into the surrounding atmosphere,

The lns 24 give reinforcement and strength to the skirt and they connect the bosses I9 with the ribs 25 as shown in Figure 5. The vertical ribs 25 extend the full height of the piston and skirt and are cast in one with such piston parts. The

bands

22 and 23 end in spaced relation from the vertical ribs 25 leaving a hollow space, which, when machined creates oil channels opening through the piston permitting the passage of lubricant to the walls of the cylinder and skirt.'

(See Figures 6 and 9.) These vertical ribs 25 merge at their upper ends with the end portions of the group I1 of horizontal ribs which pass across beneath the piston top I I. If at this point attention is directed to Figure 3, it will be seen that the group of four ribs I1 which pass across horizontally beneath the piston top are in alignment with the group of four vertical ribs 25, and that these four vertical ribs 25 pass downwardly all the way from the top II of the piston to the very bottom thereof. f The lower ends of the Vertical ribs 25 merge with the inturned flange 26 at the bottom of the skirt and thus the lower ends of such vertical ribs 25 are reinforced horizontally, kept from spreading and united in a manner which will add desirable rigidity to the lower portion of the piston skirt; while at the same time providing adequate areas for the conduction of the heat away into the crank case space.

By an examination of Figure 2 the vertical ribs 25 will be seen to preferably taper from relatively great width at the top corner portions of the piston down to the lower inturned flange 26, there being preferably stepped portions 21 in the vertical ribs 25 to accord with the differential thickness of the ring column and skirt, the ribs being of greater radial width above the skirt than below same.

As shown in Figure 3 the horizontal annular rib 20 also intersects the vertical ribs 25. This horizontal annular rib 28 is placed at a favorable point in the height of the piston to subserve two functions, beside the normal function of reinforcing and strengthening the piston and acting to carry away the heat units therefrom. By an examination of Figure 3 it is seen that the horizontal annular ribl 20 is disposed just below the pairs of diametrically opposite openings 28 made through the ring column and opening through the inner and outer walls of such ring column. The horizontal annular rib 20 is also spaced directly above the external annular groove 29 which acts as a reservoir for the oil scraped from the cylinder wall by the action of the rings. As shown in Figures 1, 3 and 4 particularly, the annular groove 29 communicates with the interior space of the piston through a number of ports 38. Such ports 30 are shown to be four-in number in Figure 4 and to be located at the sides of the groups of four vertical ribs 25. The ports 30 are for the purpose of allowing excess quantities of oil in the groove 29 to escape into the interior of the piston and to drop down into the crank case without any interference from the internal horizontal annular rib 20. However, this internal annular horizontal rib 28 will prevent the splash from the cranks operating in the crank case below from working abnormal quantities of oil through the openings 28.

The openings 28 communicate with the inner or base portions of the oil ring groove 3l and with the rst ring groove 32 above it. The other ring grooves are shown to be three in number and are designated 33, 34 and 35 from bottom to top in the order named. The oil ring is designated at 36', the first compression ring at 31 and the remaining compression rings at 38, 39 and 40.

As shown more particularly in Figures 2, 3 and 9, the upper outer corner portion of the oil ring 36 is beveled as indicated at 4I in order to diminish the bearing surface of the outer edge of the ring upon the cylinder wall whereby to avoid the eiect of the rocking of this ring upon such cylinder wall. The beveled part 4I also increases the annular chamber 42 formed between the oil ring 36 and the rst compression ring 31. This chamber 42 has considerable radial extent by reason of the faci-J that the segment 43 of the ring column between the oil ring 36 and the rst compression ring 31 is undercut, or cut back from the vertical line of the outer wall of the ring column. This annular chamber 42 receives oil splashed through the openings 28. Fumes, gases and products of combustion escaping downwardly through the upper compression rings will be' received into the annular chamber 42 and will thence nd diametrically disposed exit through the openings 28 into the internal space of the piston and thence downwardly into the crank case.

Referring more particularly to Figures '7 and 8. and also to Figure 6, the bosses I9 which receive the wrist pin 44 are formed with vertical oil receiving openings 45 in their upper sides through which oil may be splashed. -In line with these openngs 45 are openings 46 in the bearing sleeves 41. Openings 45 and 46 aline with annular grooves 48 in the ends of the wrist pin 44. At the lower sides of the bosses I9 are sockets 49 into which are removably introduced locking pins 5D. Such pins are provided with reduced noses 5I for engaging into the'annular grooves 48 of the wrist pins 44. Thus the wrist pins may rotate in the bosses and at the same time be lubricated. Cotter pins 52 may be employed to hold the locking pins 50 in place. The cotter pins 52 lie in keyways 53 intersecting the sockets 49. The locking pins may be perforated in alignment with the keyways 53 to permit passage of the cotter pins therethrough. It will be noted that the vertical encaisse thickness of the piston and oil rings is graduated, the same increasing from the oil ring up to the top compression ring.

Figure 9 is a section taken on the line -g in Figure l. This Figure 9 shows the lubricating openings 30a discharging into the channel 3th.

The ribs 25 are very important as they carry the heat down the skirt. The oil splashes from the connecting rods and enters the openings 3@ and S. These openings are in line with the ends of the connecting rod bearings. The oil which issues out of the openings 3@ and 30a encircles the piston in the

channels

29 and 30", lubricating the walls of the cylinder and skirt, and also connecting the skirt to the cylinder wall by nlm of oil. The heat running down the ribs 25 is easily absorbed by the water or air that surrounds the cylinder because of the oil nlm above referred to which makes transference of the heat by conduction easy and rapid.

The durability of the piston and all other parts is dependent upon lubrication. Hence the improved piston is of durable and long life due to the lubricating properties of the same. The durability is also dependent on the cooling of the piston and the maintaining of the same in a cool condition, preventing scoring of the cylinder and skirt walls. This cooling is accomplished by the ribs 25 and the other interior rib and'n construction of the piston.

The improved piston will function better due to the fact that it is well lubricated. For this reason the engine produces greater power and is more economic in the matter of fuel.

The invention is well adapted, not only for Diesel engines, but also for such large engines as U. S. submarine engines having a 12 inch bore and employing gasoline for fuel. The invention is also applicable to airplane engines and all types of engines having large bore. In such large bore engines it is common to maintain a compression of 400 pounds and an explosion value of 4,000 pounds. Therefore, the rib reinforcement in the piston is useful in such engines in order to maintain the piston against distortion and in its true original condition. The improved lubricating arrangement also helps to this end and to reduce the great friction against the cylinder wall in engines of this character. Referring to Figure 7, the groove 48a is disposed in approximately the center of the connecting rod when assembled. The groove is an oil groove maintaining lubrication to the connecting rod bearing; the lubricant being admitted from the top or through the connecting ro. r f

The improved piston is cast in one solid mass. It can be made of case iron, steel, aluminum, alloy or other desired material.

It is obvious that various changes and modications may be made in the details of construction and design oi the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

l. An improved piston comprising a top wall, ring column, skirt, and bosses extending inwardly from said skirt and leaving free wall portions of the skirt therebetween, said ring column and skirt having vertical groups of spaced apart ribs, said groups being mounted in diametrically opposite pairs, one pair of ribs having its lower end portions merging with said bosses, the other pair of groups of vertical ribs lying in-the free sides of said piston and extending from end to end of the piston, said ring column having an internal substantially horizontal annular rib at its lower portion intersecting said vertical ribs, said ring column having an external oil groove lying below said annular rib, said ring column having therein oil openings above said annular rib, oil and compression rings carried by said ring column, said ring column having a radially reduced portion between the oil ring and thel next compression ring and with an undercut portion therein to form an annular chamber between said rings in communication with said openings.

2. A11 improved piston comprising a top wall, ring column, skirt, and bosses extending inwardly from the skirt at opposite sides and leaving free sides of the piston between said bosses, horizontal intersecting groups of ribs extending downwardly from said top wall, groups of vertical ribs extending down the sides of said ring column and skirt, the groups at the boss sides of tne piston merging with said bosses, the groups of vertical ribs at the free sides ofthe piston extending from end to end of said piston, a horizontal annular rib extending from the lower portion of the ring column and intersecting said groups of vertical ribs, conducting bands extending partly around the skirt from the upper and lower portions of said bosses, and fins extending partly around the skirt from the intermediate portions of said bosses, said bands and iins extending to the sides of the groups of vertical ribs at the free sides of the piston.

3. An improved piston comprising a top wall, ring column, skirt and bosses extending inwardly from the skirt and leaving free side portions between said bosses, groups of intersecting horizontal ribs on the top wall extending downward therefrom, groups of vertical ribs extending downwardly from the top wall along the ring column and skirt, blocks merging with the upper portions of the bosses and with the lower portions of the groups ofvertical ribs at the boss sides of the pistons, the vertical ribs at the free sides of the piston having stepped inner edges opposite the step between the ring column and skirt, said last mentioned ribs tapering in width from top to bottom and extending substantially 6d the full length of the piston.

ALEXANDER M. ALEXANDRESCU.