Valve rotator

A valve rotator for a valve in an internal combustion engine. The rotator has a body and a cap which surround the valve stem and are movable toward and away from each other. Coacting with the cap and the body are a spring washer for transferring axial load from the cap to the body, and a shiftable element or elements carried in one or more pockets in the body and in contact with the spring washer. A fulcrum is provided for shifting the load from the shiftable element directly to the body whereby the shiftable element is reset for effecting rotation when the load on the spring washer is reapplied to the shiftable element. The technical advantage of the present invention is that a much simpler, less expensive structure capable of smaller axial dimension than prior commercial structures is provided for a rotator operable on the valve closing stroke.

BACKGROUND OF THE INVENTION AND PRIOR ART 
The present invention relates to a valve rotator and more particularly to a 
rotator for a valve in an internal combustion engine, particularly a 
diesel engine. Such devices are also finding increasing use in spark 
ignited engines. 
Valve rotators for rotating internal combustion engine valves achieve two 
purposes. The first of these is to rotate the valve, particularly exhaust 
valves, so that the hot exhaust gases directly impinge on a different 
portion of the valve face on each stroke. This minimizes burning of the 
valve and consequent loss of compression, and extends the lift of the 
valve and valve seat. Whereas it was not uncommon to rebuild diesel 
engines after 75,000-100,000 miles of use, the current demand is that the 
engine should not require rebuilding for any reason prior to 300,000 miles 
of use. The use of valve rotators aids in the achievement of improved 
engine life through their beneficial effect on the valves and valve seats. 
Typical examples of prior art valve rotators which rotate the valves on the 
valve opening stroke will be found in the patent to Updike U.S. Pat. No. 
4,094,280, the patents to Tauschek U.S. Pat. Nos. 3,952,713, 4,003,353, 
and 4,075,987, the patent to Orent U.S. Pat. No. 3,537,325, the patents to 
Norton U.S. Pat. Nos. 2,516,795 and 2,761,434, and the patent to Thorne 
U.S. Pat. No. 2,624,323. 
Another type of valve rotator is utilized not only for the purpose of 
presenting a different surface for the hot gases upon each cycle, but also 
for the purpose of cleaning the valve seat by effecting rotation of the 
valve face against the seat at the time of closing. These rotators operate 
upon the valve closing stroke and wipe deposits, such as carbon deposits 
away from the valve seat to be blown out of the combustion chamber by the 
rush of exhaust gases, for example, or by the in-rush of fuel air mixture. 
An example of a valve rotator which operates on the valve closing stroke is 
shown in the patent to May U.S. Pat. No. 3,710,768. 
Other references of interest in the field of valve rotators include the 
patents to Schonlau U.S. Pat. No. 3,890,943, Enke U.S. Pat. No. 3,717,133 
Dooley U.S. Pat. No. 2,935,058, Geer U.S. Pat. No. 2,827,886 and Newton 
U.S. Pat. No. 2,582,060. Lash adjusters which cause valve rotation in both 
directions (clockwise and counterclockwise) are shown by Leake U.S. Pat. 
No. 2,875,740. Witzky U.S. Pat. No. 2,775,232 shows a different type of 
device utilizing an offset rocker arm. Sward U.S. Pat. No. 2,662,511 shows 
a combined rotator and lash adjuster. 
It will be observed from a review of the prior art structures that each is 
characterized by basic elements including a rotator body, a rotator cap, 
shiftable element or elements which coact between the cap and the body, 
and, with the exception of the lash adjusters, a spring washer, e.g., a 
Belleville washer. The valve spring is usually seated with one of its ends 
in engagement with the rotator cap. The rotator body usually rests on the 
cylinder head. The shiftable elements may be either a side loaded coil 
type garter spring, or a series of steel balls carried in individual 
circumferentially extending pockets each having a sloping ramp along which 
the balls move. To bias the balls toward the upper end of the ramp there 
are provided individual coil springs. The balls project above the surface 
of the rotator body at each position along the ramp for contact with the 
spring washer. The spring washers in such prior art devices are arranged 
so that one peripheral edge of the washer is in contact with the cap, and 
the other peripheral edge is normally in contact with the body of the 
rotator. The ball raceway is located between the peripheral edges of the 
spring washer. 
As the load is increased on the balls by increasing the valve spring load 
during opening of the valve with a rocker arm, the rotator cap is moved 
toward the rotator body and the balls forced down the ramps overcoming the 
bias of the coil springs. Movement of the balls down the ramp causes the 
spring washer to rotate relative to the frictionally held rotator body. 
Movement of the washer about the valve axis transmits a rotatory motion to 
the cap with which it is frictionally engaged. The valve spring which is 
seated against a retainer near the distal extremity of the valve is 
rotated because of its frictional engagement with the rotator cap. The 
rotational movement of the valve spring is transmitted to the valve 
through the retainer which is locked to the valve stem. When the valve 
reseats, it is in a different angular position from what it was when the 
cycle began. Valve rotators, as distinct from lash adjusters, effect a net 
positive rotation in a predetermined direction during the valve opening 
and closing cycle. To achieve net positive rotation in one direction a, 
one way clutch system is utilized to inhibit counter-rotation. In these 
valve opening rotators, the rotator body and rotator cap are located on 
opposite sides of the spring washer. 
The patent to May, supra, explains the operation of a device which operates 
on the valve closing stroke. In FIGS. 1 and 2 are shown commercial 
structures which operate on the valve closing stroke and which are 
characterized by a plurality of spring washers, and a bearing race. In 
these valve closing rotators, the rotator body and rotator cap are located 
on the same side of the spring washer. 
It is a primary object of the present invention to simplify the prior art 
structures operable on the valve closing stroke, and particularly those 
shown in FIGS. 1 and 2, by eliminating parts and to make them less 
expensive to manufacture. The improved structures hereof can also have a 
smaller axial dimension, and are less susceptible to fouling by dirt. To 
achieve these ends a rotator body having a structure like that normally 
used in the fabrication of a valve rotator operable during the opening 
stroke may be modified by the provision therein of a "fulcrum". The 
fulcrum transfers the valve spring load normally proceeding from the cap 
through the spring washer and the shiftable element or elements to the 
body of the rotator, to a condition where the load proceeds from the cap 
to the spring washer and directly to the body. The load is thus relieved 
from the shiftable element or elements and the cap and body frictionally 
clutched against relative rotation by the spring washer. Release from the 
load on the shiftable element or elements allows the shiftable means to 
"shift" to a different position relative to the cap and body parts (for 
example, the balls are forced up the ramp). When the valve spring load is 
reapplied to the shiftable means from the spring washer as the cap and 
body move relatively apart, and the spring washer comes off the "fulcrum", 
the shiftable means is contacted thereby under a heavy load and is 
displaced in the opposite direction (for example, the balls are forced 
down the ramp). This causes declutching of the cap and body and enables 
relative rotation between the cap and the body as will be hereinafter more 
particularly described. 
The provision of means for releasing the load on the shiftable element or 
elements during a valve stroke to enable such element or elements to 
assume a different position, distinguishes the present invention from the 
prior art. 
BRIEF STATEMENT OF THE INVENTION 
Briefly stated, the present invention is in the provision of an improved 
valve rotator for a valve in an internal combustion engine which valve is 
reciprocable between open and closed positions along its longitudinal axis 
and rotatable about said axis. The rotator includes first and second parts 
which are movable axially relative to one another in response to forces 
which alternately increase and decrease. Means are provided for imparting 
relative rotation between the first and second parts upon relative axial 
movement of the parts. This structure includes shiftable elements located 
in a pocket or pockets in one of the parts. A spring washer is provided 
which surrounds the longitudinal axis of the valve stem. The spring washer 
is normally in contact with the shiftable element or elements and 
transmits axial load between the parts and through the shiftable elements. 
Structure is provided between one of the parts and the spring washer to 
effect release of the load on the spring washer from the shiftable element 
or elements during at least a portion of the distance of relative movement 
of the parts to enable the shiftable element or elements to assume a 
different position. 
In a more specific embodiment of the invention, the structure which coacts 
between the part and the washer to effect release of the load is a 
"fulcrum" over which the spring washer is rocked during movement of the 
parts toward or away from one another and whereby the load on the spring 
washer is released from the shiftable elements to permit such element or 
elements to assume a different position between the parts while the parts 
are clutched together against relative rotation. On relative movement of 
the parts in the opposite direction, the load is reapplied to the element 
or elements now in the different position thereby forcing the element or 
elements back and simultaneously effecting relative rotation between the 
parts, which are now in a declutched condition. 
The fulcrum may be integral with one of the parts, e.g., the body of the 
rotator, or may be a separate element interposed between one of the parts 
and the spring washer, e.g. a separate ring. The fulcrum is located 
intermediate the inside and outside peripheries of the spring washer and 
is preferably located midway between the inside and outside peripheries of 
the spring washer.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now more particularly to the prior art structures shown in FIGS. 
1 and 2, there are here shown commercially available rotators in cross 
section. The illustrated rotators are operable on the valve closing 
stroke. The valve rotators 10 each include a body portion 12 adapted to be 
seated on its lower surface 14 on a cylinder head. The body 12 is provided 
with an axial bore 16 dimensioned to surround a valve stem and, in most 
cases, a valve guide portion. The body portion 12 is provided with a 
collar 18 keyed thereto by a key member such as projection 20 to prevent 
relative rotation between the collar 18 and the body portion 12. The 
collar 18 is provided with a series of pockets 22 circumferentially 
disposed thereabout, each pocket including a shiftable member, for example 
a ball 24. The pockets 22 are provided with a ramp surface (not shown) 
which controls the extent of projection of the ball out of the plane of 
the lower surface of the collar 18. 
The structures shown in FIGS. 1 and 2 are also provided with a cap 26 which 
is movable in an axial direction relative to the body portion 18, and is 
also rotatable about the axis of the valve stem. The cap portion 26 serves 
as a seat for the valve spring which rests against the surface 28, and 
exerts a variable force on a spring washer 30 with which the lower lip 32 
is in frictional contact. The rotators of FIGS. 1 and 2 effect rotation of 
the valve by means of rotating the valve spring (not shown) which in turn 
rotates the valve spring retainer locked to the distal extremity of the 
valve stem. Hence, when rotation of the cap 28 of the rotator 10 is 
effected the valve is caused to rotate. The spring washer 30 must also 
rotate. Because of its frictional engagement with the lower lip or edge 
32, it has been found necessary to mount the inner periphery 34 on a 
suitable bearing means generally indicated at 36 to enable such rotation. 
In FIG. 1 the bearing 36 is a roller bearing and race. In FIG. 2, the 
bearing means consists of a second spring washer 38 mounted on a series of 
roller balls 40 carried in a suitable circumferential ball race 42. The 
cap 26 and the body 12 are each on the same side of the spring washer 30. 
The prior art structures of FIGS. 1 and 2 are commercially available and 
operate substantially in the manner taught by May in U.S. Pat. No. 
3,710,768. It is structures such as these that are simplified, made less 
costly, and with smaller axial dimension. 
One internal combustion engine of relatively small size had a restricted 
valve spring space and could not accept as a replacement for a 
conventional valve opening rotator a valve closing rotator of the type 
shown in FIGS. 1 and 2. It would accept a structure of the present 
invention having the smaller axial dimension. The valve closing structures 
of this invention have the advantage of being insertable in place of 
currently used valve opening rotators without necessitating a change in 
the valve springs to achieve the proper load. The illustrated commercial 
prior art structures cannot be so substituted without necessitating a 
change in overall axial height or a change in the valve spring to retain 
proper loading. 
Referring now more particularly to FIGS. 3-8, there is here shown a valve 
assembly including a rotator for the valve which embodies the present 
invention. FIG. 3 shows in fragmentary cross section a cylinder head 50 
including a valve exhaust port 52. The exhaust port 52 is closed by a 
valve 54 having a valve head 56 and a valve stem portion 58. In order to 
bias the valve to a valve closed position such as shown in FIG. 3, there 
is provided a valve spring 60 seated at one end against a spring retainer 
62 locked in a known manner to the distal extremity of the valve stem 58 
by means of "keepers" 64. The spring 60 is biased between the cylinder 
head 50 and the retainer 62. In present invention, a valve rotator 
assembly generally indicated at 66 is interposed between the cylinder head 
50 and the lower end 68 of the valve spring 60. In certain installations, 
the valve rotator assembly is interposed between the retainer 62 and the 
upper end of the valve spring 60. 
The rotator 66 is composed of a rotator body 70 which is adapted for 
seating engagement against the cylinder head 50, and a rotator cap 72 
which provides a seat for the bottom end 68 of the valve spring 60. The 
cap 72 is dimensioned for movement in an axial direction relative to the 
body 70 in response to increase and decrease in load exerted against the 
cap by the spring 60 as the valve is moved between the open and closed 
positions by the rocker arm or cam (not shown). 
The cap 72 is provided with a lip portion 74 having an inner diameter 
slightly less than the outer periphery 76 of the body 70. The inner 
periphery of the cap 72 is provided with a sleeve portion 78 dimensioned 
for a loose fit around a valve guide portion 80. 
As indicated above, the cap 72 and the body 70 are arranged for movement 
toward and away from each other in response to changes in the load exerted 
by the spring 60. Interposed between the cap 72 and the body 70, there is 
a spring washer 82 of the Belleville type for urging the parts 72 and 70 
axially apart. The cap 72 and the body 70 are located on opposite sides of 
the spring washer 82. 
In the embodiment shown in FIG. 3, the inner periphery 84 of the spring 
washer 82 is located for engagement with the cap 72 under a flange portion 
86. The outer peripheral edge portion 88 is adapted for frictional 
engagement and load transmitting engagement with shiftable elements. As 
shown in FIG. 3, the shiftable elements include a plurality of 
circumferentially disposed steel balls 90. As best shown in FIGS. 4 and 5, 
the steel balls 90 are carried in individual circumferential pockets 92 
formed in the upper surface of the body 70. The pockets 92 may be formed 
by any suitable means, e.g., milling, stamping, forging, etc. The pockets 
92 have an arcuate configuration as shown in FIG. 4, and are provided with 
a ramp portion 94 along which the ball 90 is adapted to roll or slide 
(FIG. 5). In order to urge or bias the ball 90 toward the shallow end 96, 
there is provided a coil spring 98 in contact with the ball 90 at one end, 
and with the end wall 100 of the pocket 92. When the load is released from 
the spring member 82, as will be described hereinafter, the spring 98 
urges the ball 90 up the ramp 94 toward the shallow end 96. In general, 
from 5 to 7, e.g., 6 of the pockets 92 are provided each containing a 
shiftable element 90 and biasing spring 98 for returning the element 92 to 
the shallower end 96 of the pocket 92. The cumulative axial force 
generated by the biasing springs 98 is less than the minimum force of the 
alternately increasing and decreasing valve spring forces. 
The rotator body 70 in the present invention is also provided with a 
fulcrum 102 which in the embodiment shown in FIG. 3 is an integral 
circular rim projecting in an axial direction from the top surface 103 of 
the body 70. The coaction of the spring washer 82 with the fulcrum rim 102 
is best shown in FIGS. 6-8. The outside diameter of the spring washer 82 
is greater than the pitch diameter of the ball sockets. 
FIG. 6 shows the valve 54 in the valve opening mode as the valve face 57 is 
lifted off the valve seat 59. In this condition, the load on the valve 
spring 60 is increased and exceeds the summation of the mean flattening 
load of the Belleville spring 82 and the combined axial force of the 
spring 98, and the cap 72 is urged toward the cylinder head 50, on which 
the rotator body 70 is seated, and toward the body 70. The movement of the 
rotator cap 72 toward the rotator body 70 decreases the axial spacing 
between the two parts and forces the spring washer 82 to pivot about the 
balls 90, and come quickly into contact with the fulcrum or annular rim 
102. When the valve rotator is loaded by the cam or rocker arm at or near 
the valve closed point, i.e., just as the valve begins to open, the spring 
washer 82 should make contact with the fulcrum stop 102. This contact is 
shown in FIG. 6. The balls 90 are at the lowest or deepest part of the 
pocket 92 albeit still projecting above the surface 103 of the body 70 an 
amount sufficient to enable engagement with the spring washer 82. 
In FIG. 7, the axial movement of the cap 72 toward the rotator body 70 is 
of a sufficient magnitude to release the load imparted by the spring 
washer 82 on the balls 90 and transfer it to the fulcrum 102. In FIG. 7 
the spring washer 82 is shown as being cammed off the surface of the balls 
90 by the fulcrum rim 102. This action "clutches" the body 70 to the cap 
72 through the spring washer 82 and prevents relative rotation between 
these parts. Although separation of the spring washer 82 from the balls 90 
does not happen in actuality, it is illustrated in this manner for 
clarity. When the load is released from the balls 90, the springs 98 are 
free to urge the balls 90 up the ramp 94 to the shallower end 96 of the 
pocket 92. 
In FIG. 8, the balls 90 are now at the point of greatest projection from 
the pockets 92, i.e., at the shallower end 96 of the pockets 92. As the 
valve 54 begins to reseat itself in response to movement of the valve 
actuating cam, the load on the valve spring 60 which is at or near its 
maximum value is again transferred to the balls 90 (which now project 
farther from the surface 103) through the spring washer 82 which has now 
been lifted off the fulcrum or annular rim 102 due to movement apart of 
the cap 72 and the body 70. This action releases the cap 72 for rotation 
relative to the body 70. Under the loading conditions now obtaining, the 
balls 90 are again loaded and are forced from their newly assumed position 
at the shallow end 96 down the ramp 94. In moving down the ramp the balls 
overcome the bias of the springs 98, and exert a reaction force on the 
spring washer 82 tending to rotate the washer 82. This reaction force is 
transmitted through the frictional contact line 83 at the inner periphery 
84 to the portion 86 of the cap 72. The reaction force of the balls being 
forced to roll down the ramps causes rotation of the spring washer 82 in 
the direction of the slope 94 (which may be clockwise or 
counterclockwise). The rotation of the cap 72 is transmitted to the valve 
spring 60, and from the valve spring 60 to the spring retainer 62 which is 
locked to the valve stem 58 by the keepers 64. In this manner, the 
rotational effect of the balls moving along the ramps 94 in the pockets 92 
is transmitted to the valve 54. 
It will be noted that in the embodiment shown, the rotational effect occurs 
on the closing stroke of the valve and not on the opening stroke as is 
usual with structures of this kind. Were it not for the interposition of 
the fulcrum or annular rim 102, the structure shown in FIGS. 3-8 would 
operate to effect rotation of the valve 54 on the opening stroke as the 
cap 72 moved in an axial direction toward the rotator body 70. It will 
also be noted that a "one way clutch" effect is provided resulting in net 
positive rotation of the valve in a predetermined direction. The parts so 
"clutched" are the cap 72, the body 70 and the spring washer 82. 
With the exception of the modification of the rotator body 70 to provide 
the fulcrum rim 102, and the spring constant of the springs 98, the other 
parts necessary for constructing a valve rotator are the same whether the 
device is to be utilized as a rotator operable on the valve opening 
stroke, or a valve rotator operable on the closing stroke. The effect on 
inventory requirements in supplying both types of valve rotators is 
evident. 
It should be noted that the spring constant of the springs 98 in the normal 
valve opening rotator is sufficient to exert a cumulative axial force in 
combination with the spring washer 82 to force the cap 72 and body 70 
apart when the valve is closed with the balls 90 located at the shallow 
end of the pockets 92. In the valve closing rotator, the balls are at the 
deep end of the pockets when the valve is closed, and the springs 98 are 
insufficient to move the balls up the ramps and overcome the load of the 
washer 82 and the valve spring. In the valve closing rotators of this 
invention, the cumulative axial force of the springs 98 is less than 60%, 
e.g., about 30%, of the mean flattening load of the spring washer. The 
spring washer 82 has a mean flattening load sufficient to force the cap 72 
and body 70 apart while the balls 90 are at the deeper end of the pockets 
92. 
The principles of the present invention can also be embodied where the 
shiftable element instead of being a series of steel balls 90 carried in 
individual arcuate circumferentially spaced pockets 92, is a side loaded 
coil type garter spring 104. The spring 104 is carried in a 
circumferential groove 106 milled into the upper surface 84 of the rotator 
body 70. The mode of operation of the rotator illustrated in FIGS. 9, 10 
and 11 is essentially the same as the mode of operation of the rotators 
shown in FIGS. 3-8. However, instead of balls shifting in individual 
pockets 92, loading of the side loaded coil spring 104 causes the coils of 
the spring 104 to slope at a more acute angle with respect to the cap 70. 
As the load on the spring 60 is released, the torsional forces stored in 
the coil spring 104 bear on the spring washer 82 with a "zero slip" load 
urging it in a predetermined direction as the spring load is released from 
the cap 72. Rotation of the valve 54 is effected in the same manner as 
described above in connection with FIGS. 3-8. 
FIGS. 12-14 show another embodiment of the present invention and wherein 
the shiftable elements, such as the balls 90, are on a smaller radius than 
the radius of the rim 102. In FIGS. 3-8, the shiftable elements were on a 
radius larger than the radius of the fulcrum or rim 102. In the embodiment 
shown in FIGS. 12-14, the spring washer 82 is in a position inverted from 
that shown in FIGS. 6-8. The balls 90 contact the spring washer 82 at its 
inner peripheral portion 84, and the outer peripheral portion 88 is in 
frictional circumferential contact with the cap 72. In order to center the 
spring washer 82, the inner peripheral edge 82 is seated against an 
integral collar portion 73 projecting axially toward the cap 72. For ease 
of assembly, the diameter of the inner face 75 of the rotator body 70 is 
slightly larger than the external diameter of the valve guide portion 80. 
FIG. 13 shows the condition of the system when the valve is in the open 
position, and the spring washer 82 is engaged with the fulcrum rim 102. In 
this condition, the load is released from the balls 90, and the springs 98 
in the pockets 92 (FIG. 5) are now able to urge the balls toward the 
shallower end 96 of the pockets 92 in the same manner as set forth in 
connection with the discussion of FIGS. 3-8. When the load is returned to 
the balls 90 by movement of the cap portion 72 away from the body portion 
70 in response to decreased load exerted by the spring 60, rotation of the 
washer 82, the consequent rotation of the cap 72, the spring 60, the 
spring retainer 62 and in turn the valve stem 58, may now occur in the 
manner described above. 
In the structures shown in the annexed drawings, the mean flattening load 
of the spring washer 82 in the free state must be between the minimum load 
generated by the valve spring 60 when the valve is closed, and the maximum 
load generated by the valve spring 60 when the valve is open. The 
cumulative axial load of the spring washer 82 and the axial component of 
force of the springs 98 should be in equilibrium with the minimum load 
generated by the valve spring 60 when the valve is in the valve closed 
position. If the cumulative axial load is greater, it will tend to 
compress the valve spring 60 and permit the balls to rise from the bottom 
of the pockets. The balls 90 initially support the periphery of the spring 
washer when at the bottom of the pockets 92. The cumulative axial force 
generated by the spring washer 82 and the summation of the axial forces 
generated by the springs 98 must be also in equilibrium with the load 
generated by the valve spring 60 when the valve is fully opened. To 
prevent the spring washer 82 from deflecting beyond the flat condition 
when the valve is open, the mean flattening load is designed to be at a 
level greater than the valve open load when supported on the fulcrum. 
Preferably the mean flattening load under this condition is about 10% 
greater than the valve open valve spring load. 
In a specific engine test using an IHC V-345E Rig Engine, the valve open 
load on the valve spring was 190 l bf. and the valve closed load was 63 l 
bf. The valve spring was a right hand coil spring with a damper. In this 
engine, valve rotational speeds of about 6 rpm were achieved at a camshaft 
speed of 600 rpm rising to a maximum of about 9 rpm at 1000 rpm camshaft 
and declining almost linearly as the camshaft speed was increased to 2000 
rpm where about 1.71 rpm of the valve were obtained. In this test, ball 
return springs 98 were used. Best results were obtained when the 
cumulative axial force of the ball springs (R4-4-7) on the washer O.D. was 
about 42 lbf. The spring washer utilized was an RO-551-5 standard spring 
washer having a mean flattening load of 160 l bf. The balls were 6 in 
number and 0.1875" diameter. The overall dimension of the rotator was 
1.875" diameter.