US2353779A - Cylinder attaching means - Google Patents

Description

July 18, 1944; v. I. MONCRIEFF 2,353,779

CYLINDER ATTACHING. MEANS Filed Oct. 9, 1941 2 sheets-sheet'l INVENTORI Veon I. Mon crzef? y mM ATTORNEY y 1944. 'v. L'MONCRIEFF 2,353,779

7 I CYLINDER ATTACHING MEANS Filed 001:. 9, 1941 2 Sheets-Sheet '2 INVENTOR VeonLMoncrze-ff ATTORNEY.

Patented July 18, 1944 2,353,779 CYLINDER AT'IACHIN G MEANS Veon I. Moncriefl, West Hartford, Conn., assignor to United Aircraft orporation, East Hart- 7 ford, Conn., a corporation of Delaware Application October 9, 1941, Serial No. 414,319 Claims. (01. 123-171) This invention relates to improvements in internal-combustion engines and has particular reference to an improved arrangement for secur ing the cylinders of such an engine to the engine crankcase.

An object of the invention resides in the provision of an improved securing means for an internal-combustion engine cylinder which willpermitmore effective cooling of the cylinder and particularly of the inner or barrel portion of the cylinder.

A further object resides in the provision improved means for securing the cylinders of an air-cooled internal-combustion engine to the en} gine crankcase which will permit the extension of the finned area of the cylinder barrel approximately to the inner or crankcase end of cylinder. V

A still further object resides in the provision of improved means for securing the cylinders of the a radial type of internal-combustion engine to the engine crankcase which will relieve the bar; rel portions of the cylinders from the stresses due to explosion forces in the outer ends of the cylinders and thereby permit the cylinder barrel pontions to be made with a thinner wall section or to be made of a material of somewhat less structural strength than that ordinarily employed but with improved heat conducting characteristics."

Other objects andadvantages will be more particularly pointed out hereinafter or will become apparent as the description proceeds.

In the accompanying drawings, in which like reference numerals are used to designate similar parts throughout, there is illustrated, in two slightly modified forms, a suitable mechanical embodiment for the purpose of disclosing thei'n vention. The drawings, however, are for the pure pose of illustration only and are not to be taken as limiting or restricting the invention sinceit will be apparent to those skilled in the art that various changes in the illustrated embodiments may be resorted to without in any way exceed j ing the scope of the invention. 7

In the drawings,

Fig. 1 is a longitudinal sectional view through an engine cylinder and a fragmentary portionof the engine crankcase showing means constructed according to the invention for attaching the cylinder to the crankcase, the section being taken on the line ll of Fig. 2.

Fig. 2 is a transverse sectional view taken ,on the line 22 of Fig. 1 and showing a complete sectional view of one cylinder and the supporting means therefor and sectional views of fragmentary portions of adjacent cylinders and their sup-- engine cylinder secured to the engine crankcase by the improved cylinder attaching means.

Referring to the drawings in detail, and particularly to Fig. 1, the numeral It generally indicates the engine crankcase. This crankcase may be generally cylindrical in the case of a radial type of engine and may have a cylinder supporting portion separated by internal web members, as indicated at I2 and M, from chambers, as indicated at It and I8 located one at each side of the cylinder carrying portion. While an arrangement particularly adapted to an air-cooled radial type of internal-combustion engine has been particularly illustrated for the purpose of disclosing the invention, it is to be understood that this invention is not limited to any particular type of internal-combustion engine but may be used in any engine to which its principles advantageously pply.

. The webs l2 and I4 carry a. plurality of annular seats, one of which is indicated at 20, one for each cylinder, these seats being adapted to cooperate with the crankcase end of thecylinder to locate this end of the cylinder relative to the crankcase and hold it firmly in position.

The crankcase also carries a plurality of outwardly extending integral boss members concentric with the seats 20, one of which is indicated at 22, growing out of the crankcase in substantial alignment with the peripheries of the internal webs I2 and I4 and provided at their outer ends with respective integral reinforcing rings 24. These bosses extend out from the crankcase a distancesuch that when a cylinder is mounted in position on the seat 20 the rings 24 will overlie the inner ends of the respective cylinder heads.

Thecylinders, one of which is generally indicated at 26, each comprises a head portion 28 and a barrel portion 30. In the case of an aircooled engine both of these cylinder portions are provided with external heat dissipating fins, as

indicated at 32 for the head portion and 34 for position as shown in Fig. 3.

Near its inner end the barrel portion of the engine cylinder is provided with an external shoulder 36 which compresses a resilient packing member 38 between itself and an internal shoulder 4%! provided in the cylinder barrel seat 20. The internal diameter of the ring member 24 is sufficiently large so that the finned barrel portion 30 of the cylinder can be passed therethrough. In securing the cylinder to the crankcase the barrel portion is passed through the ring 24 until the threads in the ring and on the head portion can be engaged. The cylinder is then turned down upon the screw threads until the proper position of the cylinder relative to the crankcase is obtained. In this position the pack-- 'ing member 38 will be compressed between the shoulders 36 and 40 to provide an oil seal between the inner end of the cylinder and the crankcase. Preferably the boss 22 is split, as indicated by the lines 42 and 44 on Fig. 2, and apertured to receive clamp bolts, indicated at 46 and 48 in Fig. 2 and 4S and 50 in Fig. 1. With this 'a'r-' r'angement the clamp bolts may be loosened before the cylinder is turned into place and" may be tightened after the cylinder is 'put in its proper operative position relative to the crankcase to firmly secure the cylinder'in this position against forces tending to move it, such as engine vibration and valve loads, and to keep the cylinder head from becoming loose in the ring 24 due to expansive changes of the ring and the cylinder head under the influence of varying cylinder head temperatures.

In the formof the invention shown in Fig. 1

the head portion 28 and the barrel portion '30 are shown as a single unitary structure and this structure may, if desired, be formed of some suitable light weight material such as an aluminum alloy, since the stresses due to explosive forces in the cylinder are not transmitted through the relatively thin barrel portion but'are transmitted through the heavy head portion directly to the ring 24 of the cylinder securing boss. At the same time the wall of the barrel portion can be made relatively thin so that heat willbe rapidly conducted through this wall to the barrel fins 34 which may be formed by machining away a por tion of the original barrel blank or may be formed separately and attached to the barrel by some means known to the art. By thus providing a thin walled barrel of a material of excellent heat conducting properties, such as an aluminum alloy, and extending the heat dissipating fins substantially to the bottom or inner end of the barrel, the cooling 'of the barrel is materially improved. Also, because the boss 22 can be made relatively rigid and the cylinder head' 28 is'also relatively rigid, movement of the outer end of the cylinder relative to the crankcase will be materially reduced thereby giving an improved valve operation by eliminating from the valve gear the clearances due to the heat expansion of the cylinder barrel and movements due to the flexibility of this barrel under operating loads. Additionally, the cylinder attaching bosses may be made to serve as bafiles for guidingthe cooling air around the cylinder barrels.

As is particularly shown in Fig. 2, each boss is provided with a pair of diametrically opposed openings, as indicated at 52 and 54 one of which provides an entrance opening and the other of which providesan exit opening for the cooling air for the cylinder barrel. As is particularly shown in Fig. 1, these openings are extended downwardly to the outer surface of the cylinder barrel seat 20 so that the cooling air entrance and exit openings both extend over the entire length of the finned area of the cylinder barrel to insure the admission of the cooling air to all of the barrel fins. The portions of the boss on each side of the air entrance and exit openings are positioned substantially in contact with the peripheries of the barrel fins so that the cooling air is forced to flow through the spaces between the fins and a reasonably uniform distribution of cooling air over the entire length of the cyl inder barrel is obtained. The portions of the bosses between the adjacent cylinders block the flow of cooling air at these locations so that all is. forced to flow through the finned area of the various cylinder barrels.

"'Ihe'arrangement illustrated in Fig. 3 shows that the improved cylinder attaching meansis also adaptable to the attachment of acompositc cylinder to the engine crankcase. In this arrangement the cylinder barrel 56 may be formed separately from the head 58 and may, if desired, beformed of a different material. For example, the barrel 56 may be made of steel while the head 58 may be made of. a suitable aluminum alloy. The cylinder head in the illustrated arrangement, is provided near its open end with external screw threads which engage withthe internal screw threads in the ring 24 of the boss 22 andwith internal screw threads which engage with external threads formed on the barrel 5%,. to secure the barrel in operative position relative to the head 58 and the engine crankcase. In other respects the form of. the invention shown in Fig. 3 is substantially the same as that shown in Fig. 1 and described above. In the arrangement shown in Fig. 3 the barrel fins 60 extend for substantially the entire length of the cylinder barrel 56 between the head 58 and. the barrel seat 20 and cooling air is forced-t0 flow between all of these fins by the openings 52 and 54 which extend over the entire length of the finned area of.

the cylinder barrel. The barrel 56 is also provided near its inner or crankcase end with an the cylinder and the crankcase.

While a suitable mechanical embodiment has been illustrated in the accompanying drawings in. two slightly modified forms and has been hereinabove described for the purpose of disclosing the invention, it is to be understood that the invention is not limited to the particular em-- bodiments so illustrated and described but that such changes in the size, shape and arrangements of the various parts may be resorted to as come within the scope of the sub-joined claims.

Having now described the invention so that others skilled in the art may clearly understand the same, what it is desired to secure by Letters Patent is as follows:

case, a guide seat surrounding an aperture in the bottom of said depression and engaging the in ner end of said barrel portion, and means on said head portion engaging said boss at its outer end,

said barrel fins extending over substantially the entire length of said barrel.

2. In an engine having a crankcase and a cylinder comprising a finned head portion and a finned barrel portion, means for securing said cylinder to said crankcase, comprising, a diametrically split boss extending outwardly from said crankcase surrounding the barrel portion of said cylinder outside of the barrel fins and engaging with the head portion thereof, said boss having at its outer end an internally threaded reinforcing ring engaging with external threads on the adjacent end of said cylinder head and having openings therein providing a cooling air passage between said barrel portion and said boss from said crankcase to said reinforcing ring, and clamp bolts extending through the two parts of said split boss for contracting said reinforcing ring upon the threaded portion of said cylinder head.

3. In an engine having a crankcase provided with an aperture and a depression surrounding said aperture and a cylinder comprising a finned head portion and a finned barrel portion, means for securing said cylinder to said crankcase, comprising, a seat for the crankcase end of said barrel portion surrounding said crankcase aperture, a boss integral with said crankcase surrounding said depression and extending outwardly from said crankcase to overlap the barrel portion of said cylinder and engage with th head portion thereof, a cylinder portion between said head fins and said barrel fins engageable with the outer end of said boss to secure said cylinder in operative position on said crankcase, said boss having air passage openings at opposite sides thereof extending substantially from the outer end of said boss to the bottom of said depression to provide a flow of cooling air over substantially the entire length of said cylinder barrel.

e. In an air-cooled engine having a crankcase and a separate cylinder comprising an exteriorly finned head portion and an exteriorly finned barrel portion in which the finned area of said barrel portion extends from said head portion substantially to the crankcase end of said barrel portion, means for securing said cylinder to said crankcase, comprising, a seat carried by said crankcase for receiving the crankcase end of said cylinder barrel portion, said barrel when in operative position terminating substantially flush with the inner side of said seat, and a boss integral with said crankcase surrounding said seat and extending outwardly from said crankcase to overlap said barrel portion and engage with the head portion of said cylinder and hold the head and cylinder in operative position on said crankcase, said boss having an opening therein at the one side of said cylinder barrel portion and an opening therein at the opposite side of said cylinder barrel portion, said openings extending th entire length of the finned area of said cylinder barrel portion.

5. In an engine having a crankcase and a plurality of separate air-cooled cylinders each comprising an exteriorly finned head portion and an exteriorly finned barrel portion, with the barrel portion fins extending from the head portion substantially to the crankcase end of the barrel portion, means for securing said cylinders to said crankcase, comprising a boss for each cylinder extending outwardly from and integral with said crankcase surrounding the barrel portions of the respective cylinders and engaged with the head portions thereof to hold the head and cylinder in operative position on said crankcase, openings in said bosses at the front and rear sides of said cylinders to admit cooling air to said cylinder barrels, and means interconnecting said bosses between said cylinders to constitute air battles to direct said cooling air through said openings.

6. In combination, an engine crankcase, a separate engine cylinder barrel and head assembly mounted on said crankcase, air directing baflles arranged around said cylinder barrel, integral with said crankcase and removably secured to said barrel and head assembly adjacent said head, and acting as the main support for retaining said barrel on said crankcase.

7. In an engine, a crankcase, a cylinder supporting column connected at its inner end to said crankcase and extending outwardly therefrom, an opening in said crankcase inside of said column, a unitary engine cylinder assembly having a head portion and a barrel portion, means attaching said head portion of said assembly to the outer end of said column, said barrel portion of said assembly extending through said column and having an end received in said crankcase opening, said column having an opening therein for passing a cooling fluid over said barrel portion.

8. A unity air-cooled engine cylinder assembly comprising, in combination, a relatively thick finned head portion, a relatively thin finned barrel portion, and means for attaching said assembly to an engine crankcase having an extension thereon, said attaching means comprising means carried by said head portion and positioned between said finned barrel portion and said finned head portion for attachment to the outer end of said extension.

9. An air-cooled engine cylinder assembly comprising, in combination, a finned head, a finned barrel, a crankcase having an annular seat receiving one end of said barrel, the other end of said barrel being connected with said head, and supporting means connected to said head and to said crankcase for rigidly supporting said head, independently of said barrel, by said crankcase.

10. In an air-cooled aircraft engine, a crankcase, and annular seat in said crankcase, a finned barrel having one end thereof guided by said seat, a finned head secured to the other end of said barrel, and a wall member connected to both said head and said crankcase for supporting said head by said crankcase, said wall member being spaced from said barrel to form therewith an air duct for directing cooling air over said barrel fins.

VEON I, MONCRIEFF.

Images