US3195527A - Valve gear for an internal combustion engine - Google Patents

Description

I July 20, 1965 P. S. EATON VALVE am FOR AN INTERNAL COMBUSTION ENGINE Filed Nov. 7, 1963 PA UL 5. EA rokv INVENTOR BY $21140 6 ml 4 M ATTORNEYS port.

United States Patent 3,195,527 VALVE GEAR FOR AN INTERNAL COMBUSTION ENGINE Paul S. Eaton, Dearhom Heights, Mich, assignor to Ford Motor Company, Dearborn, Mich, a corporation of Delaware Filed Nov. 7, 1963, Ser. No. 322,113 11 Claims. (Cl. 12390) This invention relates to a valve gear for an internal combustion engine and more particularly to an improved push rod guide for stabilizing an individually supported rocker arm.

In a common type valve gear for an overhead valve internal combustion engine, the valve actuating rocker arms are provided with individual pivotal supports. The individual supports do not restrain pivotal movement of the rocker arm in directions normal to the valve stem axis, called lateral movement. The absence of lateral stabilization is not present in engines having .a single rocker arm shaft extending laterally of the engine since the rocker arm shaft itself stabilizes the rocker arm. Other reasons, however, make the use of individually supported rocker arms desirable.

Many methods have been employed to laterally stabilize individually supported rocker arms. One method that has been successful generally uses the push rod that transmits motion from between the cam and the rocker arm as a means for lateral stabilization. The push rod is held against lateral movement by some component of the engine, most frequently a slot broached in the cylinder head. The slot has substantially the same width as the diameter of the push rod in a direction normal to the axis 1 of the valve stem; The slot has suflicient length in the may become enlarged and permits lateral movement of the push rod and rocker arm. The wear may become sufficient to permit eventual disengagement of the rocker arm from either the push rod or valve stem or both. When the broached slot becomes worn to this degree, it is necessary to replace the cylinder head or to remachine the slot and fit oversize push rods.

Another service problem is also associated with the broached slot method of rocker arm stabilization. Be cause of the small size of the slot, it is necessary to remove the cylinder head to replace or service the tappets of the engine. This problem is particularly acute in engines having hydraulic tappets since this type of tappet requires more frequent service than the mechanical tappet.

It is, therefore, the principal object of this invention to provide an improved structure for laterally stabilizing individually supported rocker arms.

It is a further object of this invention to provide a stabilizing mechanism for individually supported rocker arms that facilitates servicing of the engine valve train component-s.

It is a still further object to provide a rocker arm stabilizing mechanism that permits removal of the tappets without necessitating removal of the cylinder head.

The valve train of an internal combustion engine embodying this invention includes a rocker arm that is pivotally supported upon an individual rocker arm sup- The rocker arm has the poppet valve engaging portion in engagement with a poppet valve. A cam posi- Patented July 20, 1965 tioned in the engine remotely from the rocker arm support actuates the rocker arm by means of a push rod associated at one end with the cam and at the other end with a push rod engaging portion of the rocker arm. The push rod passes through an enlarged aperture in a wall of the engine that is positioned contiguous to the rocker arm support. The length and Width of the aperture is greater than the external dimension of the push rod whereby the push rod is free to move in all directions relative to the aperture. Push rod stabilizing means are removably received in the aperture. The push rod stabilizing means has opposing surfaces in engagement with sides of the push rod for precluding lateral movement of the push rod and rocker arm.

As a further feature of the invention, the aperture in the wall may be made sufficiently large to permit removal of a tappet through the aperture without necessitating removal of the engine wall in which the aperture is formed.

Further objects and advantages of this invention will become more apparent as this description proceeds, particula-rly when considered in conjunction with the accompanying drawings wherein:

FIGURE 1 is a fragmentary perspective view of a portion of an internal combustion engine embodying this invention.

FIGURE 2 is a cross sectional view taken along line 22 of FIGURE 1.

FIGURE 3 is a cross sectional view taken along line 3-3 of FIGURE 2.

FIGURE 4 is an enlarged perspective view of the rocker arm stabilizing means shown in FIGURES 1-3.

Referring now in detail to the drawings, the reference numeral 11 indicates generally a portion of a cylinder block of an internal combustion engine. The depicted engine is of the V type but only a portion of one of the cylinders of one cylinder bank is shown. It is to be understood, however, that the invention is not limited to V type engines but may be practiced with engines having any cylinder configuration. The cylinder block 11 forms a cylinder bore 12 that is surrounded by a cooling jacket 13. The inner side of the cooling jacket 13 is bounded by a side wall 14 of the cylinder block 11. The outer surface of the side wall 14 defines one side of a valley formed between the opposing banks of cylinders. The lower edge of the valley is bounded by a lower wall 15 of the cylinder block 11.

A cylinder head, indicated generally by the reference numeral 16, is aflixed to the cylinder block 11. The cylinder head 16 has a lower wall 17 that abuts an upper wall 18 of the cylinder block 11. The cylinder head 16 also has an inner side wall 19, a first intermediate wall 21, a second intermediate wall 22, and an outer side wall 23 all of which are connected to an upper wall 24. A cooling cavity 25 is also formed in the cylinder head 16 between adjacent walls. It will be noted that the cylinder head 16 extends inwardly of the cylinder block side wall 14 toward the opposing cylinder bank (not shown). The cylinder heads of the respective cylinder banks and the intake manifold (not shown) cover the valley between the cylinder banks.

An intake port 27 extends through the outer side wall 23 of the cylinder head 16 and through its lower wall 17 to the cylinder bore 12. A poppet valve 28 is reciprocally supported in a valve guide 29 of the cylinder head 16 to control the flow of mixture through the intake port 27. A valve spring 31 normally urges the poppet valve 28 to a closed position.

A cam shaft 32 having a cam 33 is rotatably journaled in the cylinder block 11 in a known manner. The cam 33 acts through a valve train, now to be described, to control the position of the poppet valve 28. A tappet 34 is reciprocally supported in a cylindrical bore 35 formed at one side of as cylinder block side Wall 14. A hardened lower end of the tappet 34 engages and is reciprocated by the cam 33. The tappet 34 may be of any of the known hydraulic types, if automatic lash adjusting is desired or may be of any of the known 'rnechanic'al' types if manual tappet adjustment is preferred. 'A' hydraulic i tappet is shown.

A hemispherical socket 36 formed in the upper end of the tappet 34 receives a ball tipped lower end 37 of a tubular push rod 38. The upper end of the. push rod 38 extends through an aperture 39 formed in the upper 7 cylinder head wall 24. The aperture 39 is positioned above the tappet 34 and has an internal'dimension in excess of the external dimension of the ,tappet 34 so that the tappet 34. may be removed through the aperture 39 Without'necessitating removal of the cylinder head 16.

The removal of the tappet 34 may be accomplished by inserting a magnetic tool through the aperture 39 into engagement with the tappet 34.

A rocker arm indicated generally at 41, transmits reciprocatory movement ofthe push ,rod 38 into reciprocation of the poppet valve 28. The rocker arm 41 may conveniently be formed as a single piece forging, casting or "stamping. The rocker arm 41 includes a web portion 42 consisting of a poppet valve engaging end 43 and a push rod engaging end 44 separated by an intermediate hemi-' spherical bearing part 45. Stitfening ribs 46 and 47fareprovided at each side of the web portion 42.

A rocker arm supporting stud 48 is press fitted into a raised boss 49 of the upper cylinder head Wall 24. j The supporting stud 48 passes through an aperture 51 formed in the rocker arm bearing part 45 andis threaded 'at its upper end, as at 52. A washer 53 having. a lower hemispherical bearing surface is held in engagementwith the complementary hemispherical upper surface of bearing part 45 by a nut 54 that is threaded ontothreads 52. The hemispherical washer 53 provides a pivotal support fortherocker arm 41'.

A ball shapedend 55 formed onthe upper end of the push rod 38is received in a hemispherical socket 56 formed on the underside of the rocker arm push 'rod engaging end 44. The ball and socket connection insures that the upper end of the push rod 3 8'and the adjacent,

part of rocker arm 41 move in unison.

Because of the support of theuhemispherical rocker.

arm bearing .part upon the hemispherical washer 53, the push rod and valve engaging ends 44 and43 are free to move in directions normal to the axis of the valve 28.

Some means must be provided, therefore, to. stabilize the movement of the rocker arm 41 in the lateraldirection to preclude disengagement of the valve engaging end 43 from the upper end of the valve stem. For this purpose,

' a rocker arm stabilizing element, indicated generally at 57 and shown in greater detail 'in FIGURE 4, is inserted into the aperture 39.

The rocker arm stabilizing element 57 may be conveniently formed from a single piece of sheet metal and 'com- I prises a first portion 58 having a substantially circular shape viewed in a plane transverse to the push rod '38. The first'portion 58 has a diameter in excess of the diameter of the aperture 39 so that it will completely cover the aperture 39 when positioned therein (FIGURE. 7 2).

A pair of legs 59 and 61 depend from opposite sides of the first portion 58 through the upper cylinder head Wall 24 (FIGURE 3). Theflower end of the legs 59 'and61 are formed with outwardly extending projections 62 and 63 that are arcuate in shape. The projections 62 and 63 have a diameter in excess of the diameter of the aperture 39 whereby the legs 59 and 61 must be resiliently compressed upon insertion of the rocker'arm stabilizing element 57 into the aperture 39.

The 'first portion 58 is additionally formed with a pair of upstanding legs 64 and 65 that have inner wall surfaces spaced at a distance that is substantially the same as the diameter of the push-rod 38. The inner surfaces thus will snugly engage the pushrod 38 (FIGURE 2) and restrain ittrom lateral movement. V

During rotation of the cam 33 and reciprocation of the push rod 38, the push rod 38 is free to reciprocatebetwcen the contacting surfaces of the legs 64 and 65. Movement ,in the plane of the push rod is also permitted because of the elongation of the legs 64 and 65. This movement permits the upper end of the push rod 38 to follow the 'rod and rockerz arm,1the rocker arm may not move laterally upon its support.

If during engine operation the push it from the aperture 39. 'Anew rocker arm stabilizing member then may be inserted into the aperture '39. It should additionallybe, noted that, if the tappet 34 requires service, the rocker arm stabilizing member 57 maybe 'withdrawn fromihe, aperture 39 and a magnetic tool inserted through, the aperture. The magnetictool may then be used to withdraw the tappet 34 from the aperture 39 without necessitating removal of the cylinder head 16.

It is to be understood that this invention is not limited to the exact construction shown anddescribed, but that various changes andmodifications may be made without departing from'the spiritand scope of the invention as defined by the appended claims. j

I claim; V 1. An internal combustion engine comprising a'rocker ,arm support, a rocker arm pivoted upon said rocker arm support, a poppet value, said rocker arm having a poppet valve engaging portion in 'engagement'with said poppet valve, a cam positioned in theengine remotely from said rockerarm support, said engine having a wall with an aperture positioned contiguoussto said rocker, arm'support, a push rod associated atone of its ends withv said cam and-at its other end with a push rod engaging portion of said rocker arm for transmitting movement of "saidc'am into oscillation of said rocker arm about said 'rockerarm support, a-portionof said push rod adjacent its rocker arm engaging end extending through said aperture, said aperture being larger than the external dimensions of the adjacent portion of said push rod whereby said push rod is free to move in all directions relative tov said aperture, and rocker arm stabilizing means removably received in said aperture, said rocker arm stabilizing means including a first portion extending across the aperture on the side of the wall adjacent the rocker 7 arm support,opposing push rodengaging surfaces formed in said first portion engaging sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm, and a pair of opposing leg portions depending from said first portion through said aperture and terminating adjacent the other side of said wall.

. 2. An internal combustion engine comprising a rocker Qarm support,'a.rockerarm pivoted upon said rocker arm a support, a poppet value, said rocker armhaving a poppet valve engaging portion in engagement with said poppet valve, a cam positioned in the engine remotely from said rocker arm support, said engine having a wall with an aperture positioned contiguous to said rocker arm support, apush rod associated at one of'its ends with said cam and its other end with a push rod engaging portion of said rocker arm for transmitting movement of said cam into oscillation o fsaid rockerv arm about said rocker 'arm support,fa portion of said push rod gadjacent its rocker arm engaging end extending through said aperture, said aperture being larger than the exrod contacting surfaces of the legs 64 and 65 becomeworn, the rocker arm stabilizing member 57' may be replaced by withdrawing ternal dimensions of the adjacent portion of said push rod whereby said push rod is free to move in all directions relative to said aperture, and rocker arm stabilizing means removably received in said aperture, said rocker arm stabilizing means including a first portion extending across the aperture on the side of the wall adjacent the rocker arm support, opposing push rod engaging surfaces formed in said first portion engaging sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm, and a pair of opposing leg portions depending from said first portion through said aperture and terminating adjacent the other side of said wall, a protuberance formed on each of said leg portions adjacent the other side of said wall, said protuberances being spaced at a greater distance in the unassembled position than the corresponding dimension of said aperture whereby said leg portions must be compressed upon insertion of said rocker arm stabilizing means into said aperture.

3. An internal combustion engine comprising a rocker arm support, a rocker arm pivoted upon said rocker arm support, a poppet valve, said rocker having a poppet valve engaging portion in engagement with said poppet valve, a cam positioned in the engine remotely from said rocker arm support, said engine having a wall with an aperture positioned in opposing relation to said cam and contiguous to said rocker arm support, a tappet in engagement with said cam, a push rod in engagement at one of its ends with said tappet and extending through said aperture to engage a push rod engaging portion of said rocker arm at its other end, said aperture having an internal dimenison in excess of the external dimension of said tappet whereby said tappet may be removed through said aperture without removal from the engine of the Wall in which said aperture is formed, and rocker arm stabilizing means removably received in said aperture, said rocker arm stabilizing means having a portion thereof in engagement with at least a portion of the surface of said wall that defines said aperture and faces said push rod, the engagement between said surface and the portion of said rocker arm stabilizing means limiting movement of said rocker arm stabilizing means in at least one direction relative to said wall, said rocker arm stabilizing means having opposing surfaces in engagement with sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm.

4. An internal combustion engine comprising a cylinder block, a cylinder head afiixed to said cylinder block, a rocker arm support afiixed to said cylinder head, a rocker arm pivotally journaled upon said rocker arm support, a poppet valve, said rocker arm having a poppet valve engaging portion in engagement with said poppet valve, a cam rotatably supported by said cylinder block, an aperture formed in said cylinder head in opposing relation to said cam, a push rod associated with one of its ends with said cam and extending through said aperture with its other ends in engagement with a push rod engaging portion of said rocker arm for transmitting movement of said cam into oscillation of said rocker arm, the internal dimension of said aperture being greater than the external dimension of said push rod whereby said push rod is free to move in all directions relative to said aperture, and rocker a-rm stabilizing means removably received in said aperture said rocker arm stabilizing means having a portion thereof in engagement with at least a portion of the surface of said wall that defines said aperture and faces said push rod, the engagement between said surface and the portion of said rocker arm stabilizing means limiting movement of said rocker arm stabilizing means in at least one direction relative to said wall, said rocker arm stabilizing means having opposing surfaces in engagement with sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm.

5. An internal combustion engine comprising a cylinder block, a cylinder head afiixed to said cylinder block, a rocker arm support affixed to an upper wall of said cylinder head, a rocker arm pivotally journaled upon said rocker arm support, a poppet valve reciprocally supported in said cylinder head, said rocker arm having a poppet valve engaging portion in engagement with said poppet valve, a cam rotatably supported by said cylinder block, said upper wall of said cylinder head being formed with an aperture in opposed relation to said cam, a push rod associated at one of its ends with said cam and extending through said aperture with its upper end in engagement with a push rod engaging portion of said rocker arm, the internal dimension of said aperture being greater than the external dimension of said push rod whereby said push rod is free to move in all directions relative to said aperture, push rod stabilizing means removably received in said aperture, said push rod stabilizing means including a first portion extending across said aperture on the upper side of said upper wall, said first portion having opposing surfaces in engagement with the sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm and a pair of opposing leg portions depending from said first portion through said aperture and terminating adjacent the lower side of said upper wall.

6. An internal combustion engine as defined by claim 5 wherein said rocker arm stabilizing means includes protuberances formed on the end of each of said leg portions adjacent the lower side of said upper wall, the external dimension of said protuberances being greater in the unassembled condition than the corresponding dimension of said aperture whereby said leg portions must be compressed upon insertion of said rocker arm stabilizing means into said aperture.

7. An internal combustion engine comprising a rocker arm support, a rocker arm pivoted upon said rocker arm support, a poppet valve, said rocker arm having a poppet valve engaging portion in engagement with said poppet valve, a cam positioned in the engine remotely from said rocker arm support, said engine having a wall with an aperture positioned in opposing relation to said cam and contiguous to said rocker arm support, a tappet in engagement with said cam, a push rod in engagement at one of its ends with said tappet and extending through said aperture to engage a push rod engaging portion of said rocker arm at its other end, said aperture having an internal dimension in excess of the external dimension of said tappet whereby said tappet may be removed through said aperture without removal from the engine of the wall in which said aperture is formed, and rocker arm stabilizing means removably received in said aperture, said rocker arm stabilizing means including a first portion extending across the aperture on the side of the wall adjacent said rocker arm support, opposing push rod engaging surfaces formed in said first portion, said opposing push rod engaging surfaces being in engagement with the sides of said push rod for precluding lateral movement of the push rod, and a second portion depending from said first portion through said aperture, said second portion being engaged by the surface of said wall that defines said aperture for precluding movement of said rocker arm stabilizing means relative to said wall in at least one direction.

8. An internal combustion engine comprising a rocker arm support, a rocker arm pivoted upon said rocker arm support, a poppet valve, said rocker arm having a poppet valve engaging portion in engagement with said poppet valve, a cam positioned in the engine remotely from said rocker arm support, said engine having a wall with an aperture positioned contiguous to said rocker arm support, a push rod associated at one of its ends with said cam and at its other end with a push rod engaging portion of said rocker arm for transmitting movemeat of said cam into oscillation of,said rocker ,arrn

about said rocker arm support, a portion'of said push rod adjacent its rocker arm engaging end extending through said aperture, said aperture being larger than the external dimensions ofthe' adjacent portion of said push rod whereby said push rod is free to move in allpdirections relative to said aperture, and rocker'arm stabilizing 1 at one of its ends with said tappet and extending through said aperture to engage a'push rod engaging portion'of said rocker arm at itsfother end, said aperture having an means removably received in said aperture, said rocker i 7 arm stabilizing means havingtopposing surfaces engagsaid rocker arm stabilizing means relative to said wall in at least one direction.

9. An internal combustion engine as defined by claim I 8 wherein said opposing leg portions are normally spaced at a greater distance than the adjacent surfaces of said Wall whereby said leg portions must be compressed upj on insertion of said rocker arm stabilizing means into said aperture.

10. An internal combustion engine comprising arocker.

arm support, a rocker arm pivoted upon said rocker" arm support, a poppetvalvgsaid rocker arm having a poppet valve engaging portion in engagement with said poppet valve, a cam positioned in the engine remotely from said rocker arm support, said engine having a wall with an aperture positioned in opposing relation to said cam and contiguous to said rocker arm support, a tappet in engagement withsaid cam, a push rod in engagement internal dimension in excess, of the external dimension of said tappet whereby said tappet may be removed throughsaid'aperture without removal from the engine of the wall in whichsaid aperture is formed, and rocker arm stabilizing means removably' received in said aperture, said rocker arm stabilizing means having opposing surfacesengaging sides of said push rod for precluding lateral movement of the push rod and poppet valve engaging portions of said rocker arm, said rocker arm stabilizing means further having a pair of opposing leg portions depending into said aperture and engaging the surface of said wall thatdefines said aperture for pre- I cluding 'movement of said rocker arm stabilizing means relative to said wall in at least one direction.

. 11. An internal combustion engine as defined by claim 10 wherein said opposing leg portions are normally spaced at a greater distance than the adjacent surfaces of said wall whereby said leg portions must be compressed upon insertion of said rocker arm stabilizing means into said aperture.

References Cited by the Examiner V i UNITED STATES PATENTS 2,963,012 12/60, Kolbe 123 2,968,293 1/61- 'Kolbe 123 90 -3,086,507 4/63 Mooney 123- 90 ,FR'EDE. ENGELTHALER, Primary Examiner.

RICHARD B. WILKINSON, Examiner. V

Claims (1)

1. AN INTERNAL COMBUSTION ENGINE COMPRISING A ROCKER ARM SUPPORTING, A ROCKER ARM PIVOTED UPON SAID ROCKER ARM SUPPORT, A POPPET VALUE, SAID ROCKER ARM HAVING A POPPET VALVE ENGAGING PORTION IN ENGAGEMENT WITH SAID POPPET VALVE, A CAM POSITIONED IN THE ENGINE REMOTELY FROM SAID ROCKER ARM SUPPORT, SAID ENGINE HAVING A WALL WITH AN APERTURE POSITIONED CONTIGUOUS TO SAID ROCKER ARM SUPPORT, A PUSH ROD ASSOCIATED AT ONE OF ITS ENDS WITH SAID CAM AND AT ITS OTHER END WITH A PUSH ROD ENGAGING PORTION OF SAID ROCKER ARM FOR TRANSMITTING MOVEMENT OF SAID CAM INTO OSCILLATION OF SAID ROCKER ARM ABOUT SAID ROCKER ARM SUPPORT, A PORTION OF SAID PUSH ROD ADJACENT ITS ROCKER ARM ENGAGING END EXTENDING THROUGH SAID APERTTURE, SAID APERTURE BEING LARGER THAN THE EXTERNAL DIMENSIONS OF THE ADJACENT PORTION OF SAID PUSH ROD WHEREBY SAID PUSH ROD IS FREE TO MOVE IN ALL DIRECTIONS RELATIVE TO SAID APERTURE, AND ROCKER ARM STABILIZING MEANS REMOVABLY RECEIVED IN SAID APERTURE, SAID ROCKER ARM STABILIZING MEANS INCLUDING A FIRST PORTION EXTENDING ACROSS THE APERTURE ON THE SIDES OF THE WALL ADJACENT THE ROCKER ARM SUPPORT, OPPOSING PUSH ROD ENGAGING SURFACES FORMED IN SAID FIRST PORTION ENGAGING SIDES OF SAID PUSH ROD FOR PRECLUDING LATERAL MOVEMENT OF THE PUSH ROD AND POPPET VALVE ENGAGING PORTIONS OF SAID ROCKER ARM, AND A PAIR OF OPPOSING LEG PORTIONS DEPENDING FROM SAID FIRST PORTION THROUGH SAID APERTURE AND TERMINATING ADJACENT THE OTHER SIDE OF SAID WALL.

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