US2401211A

US2401211A - Cylinder head

Info

Publication number: US2401211A
Application number: US444033A
Authority: US
Inventors: Andrew V D Willgoos
Original assignee: United Aircraft Corp
Current assignee: Raytheon Technologies Corp
Priority date: 1942-05-22
Filing date: 1942-05-22
Publication date: 1946-05-28
Anticipated expiration: 1963-05-28

Description

2 sheets-sheet 1 May 28,- 1946. A. v. D. wlLLGods CYLINDER HEAD Filed May 22, 1942 Ik' J,

H22 drew 1m, u/zggms May 28, 1946- A. v. D. WILLGos 2,401,211

CYLINDER HEAD Filed May 22, 1942 2 Sheets-Sheet 2 for aircraft.

Patented May 28,' 1946y UNITED STATES 4Falte-.tir opel/eg,

signor to United Hartford, Conn.,

Aircraft Corporation, East a corporation of Delaware Application May 2,2, 1942, serial No. 444,033 5 claims. (ci. 12a-90) This invention relates to improvements in internal-combustion engines and has particular reference to an improved cylinder and valve Vconstruction particularly adapted for a radial, air-` cooled, valve-in-head, type of engine.

An object of the invention resides in the provision of a valve and cylinder construction so arranged that the valve operating mechanism lies substantiallyA in a plane including the longitudinal center line of the cylinder thereby eliminating to a, large extent side thrust and bending forces imposed on the cylinder by the operation of the valve actuating mechanism. ,I

A further object resides in the provision of an lengine cylinder and valve construction having head-carried valve mechanism in closures arranged on opposite sides cylinder and adapted to occupy a substantially fore-and-aft position relative to the engine so that the cylinder heads may be closely grouped on a, radial engine without interference between the valve mechanism enclosures or rocker boxes of adjacent cylinders, as disclosed and claimed in the concurrently filed application of Leonard S. Hobbs Serial No. 444,062'.

Another object resides in the provision in anV air-cooled engine cylinder, of rocker boxes arranged fore-and-aft in the direction of the cooling air iiow, to provide for the possibility of assembling the cylinder on the engine crank-case in either of two positions one hundred and eighty degrees apart in order to obtain satisfactory cylinder cooling in installations wherein the air ow may be from either end of the engine as might be the case in pusher and tractor'installations Thus, the same engine may be assembled either as tractor or a pusher, with consequent reversal of cooling airflow relative to the Y engine as awhole; yet the cooling airilow relative to the cylinder head and valves may be kept the same in either type of installation merely by reversing the cy nder and valve assembly relative to the crankcase.

. A still further object resides in the provision and valve construction ofr indicated, so arranged that either of an engine cylinder the character of the center line of the ,the engine cylinder and valve are not to be taken as limiting or restricting the invention since it will be apparent to those skilled in the art that Various changes in the illustrated arrangement may be resorted to without lin any way exceeding the scope of the invention.

Fig. l is a longitudinal sectional view -through mechanisms.

Fig. 2 is a top plan view of the engine cylinder shown in Fig. 1, and d l Fig. l3 is a view of the engine cylinder shown inFig. 1 looking from right to left.

Referring to the drawings in detail, the numeral IU generally indicates thecrankcase of an engine of the air-cooled radial type'- ThiS Crankcase is provided with apertures, one oflwhich is indicated at I2, to receive tions of cylinder barrels, one of which is generalthe lower or skirt porly indicated 'at I4. The barrel issecured to the crankcase in either of the two reversed positions `referred to above by hold-down bolts I6 passing through a. ange I8 A cylinder head, generally indicatedat 20, and

. disclosed and claimed per se in my concurrently led application Serial No. 444,032 is threaded at 2| onto the outer end of the barrel I4 and is provided with cooling fins 22. Between the head and .the flange I8 the barre1 is surrounded by a iin muil 24 tocomplete the fin srtucture and dissipate excess heat from the cylinder.

'I'he cylinder head 20 hastwo oppositely disposed

extensions

26 and 28, which support the exhaust and intake valve mechanisms. An exhaust valve seat 34 is mounted in extension 26 and from this valve an exhaust port 35 passing through the top of the cylinder head opens into an external exhaust stack 38. Extension 28 is provided with an intake valve seat 4Il-and from this valve an intake port 42 opens through the side of the cylinder to the intake pipe 44.- The upper part of extension 26 is made box-like to receive the valve spring `46, and rocker arm 48 pivoted at 49. The top ci the rocker box is covered by a plate' 5i). Similarly, the upper portion of extension 28 is made box-like to receive the intake valve spring- 52 and the intake valve rocker arm 54 pivoted at 55, and is closed by cover plate the intake port or the exhaustv port may open` through the cylinder head between the rocker boxes.

Other objects and advantages will be more particularly pointed out hereinafter or will be-4 come apparent asthe descriptionproceeds.

In the drawings, there is illustrated one em` 56. The projecting portion of -the exhaust rocker box receives the upper end of apush rod tube 58, the lower end of which is attached to a. tappet guide secured inthe crankcase I0. Tube 58^is provided with an expansion joint 59. Within tube 5B'is a pushrod 62, the upper end of which engages the rocker arm '48 andthe, lower end of which bears upon the valve tappet 64. l The lower end of tappet 64 carries a roller 66 which rides integral ,with the barre1 I4.

' the rocker arm 54 and the lower end of which bears upon the valve tappe't 16. The lower end of tappet 16 carries aroller 18 riding upon cam 80 which is also concentric with the engine crankshaft.

With this arrangement, the center lines of the' two push rods 62 and 14 are in a foreandaft plane which includes the center line of the cylinder. When the push rods are raised by the tappets against the resistance of the valve springs d6 and 52, the force exerted on the cylinder is substantially in the above mentioned plane so there areno twisting forces imposed on the cylinder, cylinder head, or rocker boxes. The only forces imposed on the rocker boxes are those due to push rod thrust since the arrangement of the rocker arms 48 and 5t compensates for the angularity of the thrusts occasioned by the outward inclination of the push rods inthe same plane. These thrust forces on the rocker boxes are easily resisted by providing suitable web members such as 82,for the exhaust side, and 84, for the intake side. Although web 84 is somewhat distorted by theposition of the intake port 42 and the intake pipe M, it is easily made of adequate strength to effectively resist the forces imposed on the cylinder head extension by push rod 14.

The above described structure also has the further advantage that it relieves the cylinder of a head having rocker boxes symmetrically disposed on opposite sides of said head, valve mec anism in said rocker boxes, cooling ns on sid cylinder and head extending outwardly therefrom at substantially right angles to the axis of `said cylinder, means for mounting said cylinder including said rocker boxes and said valve mechanism on said` crankcase between 4said. valve tappets in either one of two opposed positions relative to said valve tappets, whereby said rocker boxes may be interchanged, and means for operating said rocker box valve mechanism by said valve tappets in either of said cylinder positions.

2. In an air cooled internal combustion aircraft engine, a crankcase, a cylinder head having oppositely disposed intake and exhaust valve rocker boxes thereon, means for selectively` mounting said cylinder head on said crankcase in 'either one of twol positions one hundred and continuously changing bending stresses since the relatively large overlap of the cams 6,8 and 80 produces only a substantially balanced outward thrust on the cylinder during the intervals when both valves are open. Also, the arrangement relieves the cylinder of a large portion of the stress occasioned by the usual arrangement in which both rocker boxes are on the same' side of the cylinder'whereby one side of the cylinder must at times resist the thrust of both push rods. In the present arrangement there is, at no time, applied to the same side of the cylinder, a force greater than that occasioned by the operation of one push rod. The-present arrangement, therefore, tends to materially relieve the cylinder and cylinder head of stresses due to valve operation, thus reducing fatigue deterioration. These factors lead to a greatly increased cylinder life and permita more economical engine construction. The arrangementalso facilitatesthe battling of aradial engine within its cowl and permits the use of a cowl of comparatively small diameter.

While the -ideal fore-and-aft construction includes the valve, push rods, and the center line of the cylinder in a planedncluding the axis of rotation of the engine, it is to be understood that some deviation from those ideal conditions mayl be permitted without seriously affecting advan-l tages above described.

It is to be understood that the invention is not limited to the specic embodiment herein illustratedgand described, but.' may be used in other' ways without departure from .its spirit as defined n by thel following claims..

I claim:

1. Inan air cooled internal combustion aircraft engine having a crankcase, valve vtappets extending through said crankcase at spaced positions longitudinally thereof. a cylinder including tappets that said cylinder head may be operatively associated with said valve tappets and valve rods in either one of said two positions, whereby said rocker boxes may be reversed in position with respect to said crankcase to accommodate said cylinder head to a reversal in the direction of cooling airflow relative to said crankcase.

3. A cylinder and valve mechanism combination for either pusher or tractor type air-cooled aircraft engine installations, comprising, a cylinder including a head having cooling iins arranged to provide for the flow of cooling air in a fore and aft direction, foreand aft rocker boxes projecting from said head, intake and exhaust valves mounted on said head and having stems extending one into eachof said boxes, a valve operating 4. In a reversible cylinder construction for an aircooled aircraft engine, a cylinder head having fore and aft valve rocker boxes symmetrically disposed on opposite sides thereof, a iiuid passage extending through the top of said head between said boxes, 'a uid passage extending through the side of said head adjacent one of saidboxes, cooling ilns on said head adjacent said valve passages, and valve rocker arms in said boxes adapted to be operatively connected, when said boxes are in, either of two interchanged positions, with push rods respectively positioned fore andat of said cylinder, whereby said cylinder may be reversed in accordancewith a reversal in cooling air ilow to maintain the same direction of cooling air-r ilow over saidcooling fins and relative to said iluid passages in either of said interchanged positions.

5. In a cylinder construction for aircooled aircraft engines, a cylinderhead having integral fore and aft valve supporting extensions thereon.

a valve stem bore in each of said extensions, aiiuid passage extending through the top of said head between said valve stem bores, a uid passage extending in a generally fore and aft direc tion through theside of said head and one of said extensions, valve mechanism supported by each of said extensions including push rods respectively positioned fore and aft of said extensions, and cooling s substantially completely covering those portions of said extensions containing said valve stem bores and said iiuid passages, said cooling iins lying substantially in parallel planes normal to the centerline of said cylinder.

AND V. D. WILLGO0S.