US3563215A

US3563215A - Rocker arm guide member

Info

Publication number: US3563215A
Application number: US778434A
Authority: US
Inventors: Gray E D Ross
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1968-02-01
Filing date: 1968-11-25
Publication date: 1971-02-16
Anticipated expiration: 1988-02-16
Also published as: GB1201214A; DE1801252B2; DE1801252A1

Abstract

An overhead camshaft internal combustion engine cylinder has a plurality of inlet valves and an exhaust valve, the rocker arms of some of which are inclined or canted to the vertical; a plate is provided that cooperates with the rocker arm to assure that the rocker arm moves pivotally in a vertical direction.

Description

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United States Patent [72] Inventor Gray E.D. Ross Stock, lngatcstone, England [21 Appl. No. 778,434

[22] Filed Nov. 25, 1968 [45] Patented Feb. 16, 1971 [73] Assignee Ford Motor Company Dearborn, Mich.

[32] Priority Feb. 1, 1968 [33] Great Britain [54] ROCKER ARM GUIDE MEMBER 7 Claims, 1 Drawing Fig. [52] U.S. Cl 123/9042, 123/193, 123/9027, 123/9043, 123/9044 [5l] Int. Cl F0ll 1/18 [50] Field of Search 123/90, l9l-0, 193, l93-H, 75-B, l95

[56] References Cited UNITED STATES PATENTS 1,915,237 6/1933 Moore 123/191(O) 2,804,862 9/1957 Nedwidek l23/75(B) 2,902,014 9/1959 Leach 123/90(1'1) 3,094,977 6/1963 Sampietro 123/90(1-1)X. 3,112,740 12/1963 Sampietro l23/90(l-l) 3,166,058 1/1965 Zink 123/90(H4) 3,270,727 9/1966 Nance 123/9001) 3,352,293 11/1967 Hulten.... 123/195X 3,401,678 9/1968 Rose 123/90(H) 3,430,614 3/1969 Meacham 123/193(H)X FOREIGN PATENTS 866,872 5/1961 Great Britain 123/90(H) Primary Examiner-A1 Lawrence Smith Attorneys-John R. Faulkner and Robert E. McCollum ABSTRACT: An overhead camshaft internal combustion engine cylinder has a plurality of inlet valves and an exhaust valve, the rocker arms of some of which are inclined or canted to the vertical; a plate is provided that cooperates with the rocker arm to assure that the rocker arm moves pivotally in a vertical direction.

Pmmd Feb.-16, 1971 INVENTOR. GRAY E. D. ROSS ATTORNEY ROCKER ARM GUIDE MEMBER This invention relates to overhead camshaft internal combustion engines.

in many high performance engines, it is necessary to fit three valves to each cylinder. This is difficult to achieve from a space standpoint if the planes containing the valve rocker arms are perpendicular to the line joining the axes of the cylinders. It is, therefore, not unusual for the rocker arms to be inclined to the perpendicular to the line joining the axes. Such rocker arms are known as oblique".

Oblique rocker arms have hitherto been invariably mounted on a rocker arm shaft. This, in the case of overhead camshaft engines, has resulted in difficulties in adjusting the valve clearances. Valve clearances can be adjusted more simply in overhead camshaft engines if the rocker arms are individually stud mounted, i.e.,each pivotally mounted on a post, since the valve adjustment is effected merely by screwing the post further in or out of the cylinder head.

lt has'h itherto been impossible to combine in the same engine an overhead camshaft and oblique or inclined rocker arms which are stud mounted or mounted on posts because the overhead camshaft cams tend to rock the rocker arms on the posts about the axes of the posts.

This invention enables oblique stud-mounted rocker arms to be fitted in overhead camshaft engines. One end of each of a plurality of valve rocker arms has a part-spherical socket that seats on the part-spherical head of a stud fixed in the cylinder head; the opposite end of each of the rocker arms engages the end of a valve stem; an overhead camshaft engages the top of the rocker arms between the studs "and valves; the studs and valves are so located that at least some of the rocker arms are inclined to the perpendicular to the axis of the camshaft; and, a member rigid with the cylinder head engages the rocker arms between the studs and valves to limit rotation of the rocker arms about the axes of the studs.

The invention is hereinafter particularly described with reference to the accompanying drawing, which is a perspective view of part of the cylinder head of an internal combustion engine.

The figure shows a cylinder head that would be secured by bolts or other suitable means (not shown) to a cylinder block having a bank of in-line cylinders. For clarity, only one is shown. Each cylinder has a pair of inlet valves indicated by valve stems 3 and 5 and an exhaust valve indicated by a stem 7. The valves themselves are each conventional and are biased in the conventional manner to their closed positions by springs 8.

Studs 9, 11, and 13 are threaded at one end, and screwed into apertures in bosses extending from the head, as shown. Each serves as a post for mounting one end of one of the rocker arms. The upper end of each of the studs is formed as a part spherical bearing surface, and the studs can be locked in adjusted position by nuts 15. For clarity, only the rocker arm 16 associated with inlet valve stem 5 will be shown and described. The others are of a similar construction.

Rocker arm 16 has at one end a part spherical concave surface 17 that seats on its respective convex-ended stud 13. The opposite end of the rocker arm engages'the valve stem 5. The central part of rocker arm 16 has on its upper surface an arcuate wear portion 18 that is adapted to be engaged by a cam not shown) fixed on a conventional overhead camshaft (not shown). The camshaft is rotatably mounted on a journal 19 in a lower half bearing portion 20 supported on a platform 21. Thus, as the camshaft rotates, the rocker arm 16 pivots about stud 13.

The planes of the three rocker arms are not all perpendicular to the axis of the camshaft, but are inclined or at an oblique attitude. The canting of the rocker arms enables not only three valves but also larger valves to be used for each cylinder. However, since the cams do not exert a force perpendicular to the wear portions 18, a side force is exerted tending to rock the rocker arm 16 laterally about the axes of the stud 13. This is undesirable and is prevented by the inclusion of a guide member 22 that is fixed to the cylinder head and engages the rocker arms at a point between the studs and valves. There is a separate member 22 for each cylinder.

More specifically, the cylinder head has spaced along its length the integral camshaft bearing supporting platforms 2]. Each side of each platform is formed with a central slot 23 that is parallel to the plane in which the longitudinal axis of the cylinder bank lies. Each guide member 22 is a vertically disposed plate that at each end is split horizontally into two pieces. An upper offset or laterally bent tab part 24 is joined to a lower part 25 that is offset or bent laterally in the opposite direction and fits into the slot 23. The upper surface of the lower offset part 25 lies in the same plane as the lower surface of the upper offset part 24. The lower surface of the upper offset part 24 rests on the platform 21. The upper and lower offset parts at the opposite end of guide member 22 are bent in the same manner.

Lower camshaft bearings 20 (only one shown) seat on the platforms 21 and are secured thereto by bolts (not shown) extending through bores in the bearings to screw into the threaded apertures 26.

The lower camshaft bearings 20 have slots 27 in which the upper offset parts 24 fit. The slots 27 are parallel to but offset laterally and vertically from slots 23 in platform 21. The lower bearings 20 engage the upper surface of the lower offset parts 25, and thus prevent upward movement of the member 22. Downward movement of the member 22 is prevented by the lower surfaces of the upper offset parts 24 engaging the platform 21. Longitudinal movement of the member 22 is prevented by the member 22 engaging the bases of the slots in the platform and lower bearing.

The plate 22 has a slot 28 for guidance of each of the three rocker arms, and the rocker arms are each provided with side bearing portions 29 slidable in slot 28. The sides of the rocker arms 16 thus engage the sides of the slots 28, which prevents the rocker arms from pivoting laterally around the vertical axis of stud 13.

Valve clearances can be adjusted simply by screwing the studs 9, 11 or 13 in or out after the lock nuts have been slackened off.

There is a similarly arranged member 17 for each cylinder.

While the invention has been shown and described in its preferred embodiment, it will be clear to those skilled in the arts to which the invention pertains that many changes and modifications may be made thereto without departing from the scope of the invention.

lclaim:

1. A valve train assembly for use in an internal combustion engine of the single overhead camshaft type having a plurality of inlet valves and an outlet valve for each cylinder, including a plurality of rocker arms each pivotally mounted at one end on a post adjustably secured in the cylinder head of said engine and engageable at the opposite end with the stem of one of said valves, said rocker arms each having means between said post and valve stem adapted to be engageable by a cam on said camshaft for oscillating motion in a generally vertical direction about said post, the planes containing said rocker arms being nonparallel with respect to each other whereby cam forces exert a side loading on said] rocker arms, and plate means operably secured to said head and having means thereon cooperating with means on each of said rocker arms for guiding said rocker arm for oscillation in a vertical direction.

2. An assembly as in claim 1, said] plate means having a number of slots therein, said rocker arms each having means slidably engageable with and aligned with said slots.

3. An assembly as in claim 1, the operable securing of said plate means to said head including laterally offset portions of said plate engageable with movement restricting portions of said head.

4. An assembly as in claim 3, one of said offset portions being engageable in slots in said head for preventing lateral relative movement between said plate and head.

7. An assembly as in claim 1, said plate means at each end having an upper and a lower tab portion projecting laterally from said plate to'opposite sides thereof, said lower tab portion being engageable in slot means in said head to prevent longitudinal and lateral displacement therefrom and vertical displacement in one direction, and said upper tab portion being engageable with a portion of said head to prevent vertical movement of said plate in the opposite direction.

Claims

1. A valve train assembly for use in an internal combustion engine of the single overhead camshaft type having a plurality of inlet valves and an outlet valve for each cylinder, including a plurality of rocker arms each pivotally mounted at one end on a post adjustably secured in the cylinder head of said engine and engageable at the opposite end with the stem of one of said valves, said rocker arms each having means between said post and valve stem adapted to be engageable by a cam on said camshaft for oscillating motion in a generally vertical direction about said post, the planes containing said rocker arms being nonparallel with respect to each other whereby cam forces exert a side loading on said rocker arms, and plate means operably secured to said head and having means thereon cooperating with means on each of said rocker arms for guiding said rocker arm for oscillation in a vertical direction.

2. An assembly as in claim 1, said plate means having a number of slots therein, said rocker arms each having means slidably engageable with and aligned with said slots.

5. An assembly as in claim 3, one of said offset portions being engageable with means on said head restricting vertical relative movement therebetween.

6. An assembly as in claim 3, said movement restricting portions including means engageable with one of said offset portions preventing relative movement between said head and plate in one vertical direction, and including means engageable with another of said offset portions to prevent relative vertical movement between said head and plate in the other direction, said means including slotted and shouldered parts.

7. An assembly as in claim 1, said plate means at each end having an upper and a lower tab portion projecting laterally from said plate to opposite sides thereof, said lower tab portion being engageable in slot means in said head to prevent longitudinal and lateral displacement therefrom and vertical displacement in one direction, and said upper tab portion being engageable with a portion of said head to prevent vertical movement of said plate in the opposite direction.