U.S. patent number 3,633,556 [Application Number 04/853,032] was granted by the patent office on 1972-01-11 for guide device for multivalve-actuating bridge for an internal combustion engine.
This patent grant is currently assigned to Nissan Diesel Motor Co., Ltd.. Invention is credited to Atsushi Inoue.
United States Patent |
3,633,556 |
Inoue |
January 11, 1972 |
GUIDE DEVICE FOR MULTIVALVE-ACTUATING BRIDGE FOR AN INTERNAL
COMBUSTION ENGINE
Abstract
In the valve mechanism for internal combustion engines, with
each rocker arm actuating two or more valves through a bridge, a
device for guiding the bridge comprising a flange rigidly fixed to
a guide rod for guiding the bridge, said flange being mounted in a
readily removable manner on the cylinder head and secured thereto
by utilizing members of the valve mechanism.
Inventors: |
Inoue; Atsushi (Saitama-ken,
JA) |
Assignee: |
Nissan Diesel Motor Co., Ltd.
(Saitama-ken, JA)
|
Family
ID: |
26421494 |
Appl.
No.: |
04/853,032 |
Filed: |
August 26, 1969 |
Foreign Application Priority Data
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Sep 18, 1968 [JA] |
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43/80495 |
Sep 18, 1968 [JA] |
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43/80496 |
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Current U.S.
Class: |
123/90.22;
123/90.67; 123/90.4; 123/193.5 |
Current CPC
Class: |
F01L
1/26 (20130101); F02F 1/4214 (20130101); F02F
2001/247 (20130101); F02B 2275/34 (20130101) |
Current International
Class: |
F01L
1/26 (20060101); F02F 1/42 (20060101); F02F
1/24 (20060101); F01l 001/26 () |
Field of
Search: |
;123/90,188SP,188GC,90.39,75B,193H,90.4,90.22,90.67 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,165,344 |
|
Mar 1964 |
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DT |
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250,129 |
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Apr 1926 |
|
GB |
|
354,116 |
|
Aug 1931 |
|
GB |
|
465,540 |
|
May 1937 |
|
GB |
|
Primary Examiner: Smith; Al Lawrence
Claims
What is claimed is:
1. A guide device for guiding movement of a multivalve actuating
bridge in an internal combustion engine of the type having a
cylinder head, a pair of valves including stems slidably received
through guide sleeves fitted into the cylinder head, and means for
reciprocating said valve stems including a bridge being slidable on
a guide rod and having a pair of arms for respectively sliding the
valve stems through said guide sleeves: the guide device including
a flange resting on the cylinder head and having a pair of
apertures respectively receiving said valve guide sleeves, said
guide rod rigidly connected to said flange and projecting upwardly
therefrom, and releasable means including threads on the lower ends
of said guide sleeves and nuts respectively engaged on said
threads.
2. A guide device for guiding movement of a multivalve actuating
bridge in an internal combustion engine of the type having a
cylinder head, a pair of valves including stems slidably received
through the cylinder head, and means for reciprocating said valve
stems including a bridge having a pair of arms for respectively
sliding the stem; the guide device including a removable flange
resting on the cylinder head and having a pair of apertures
respectively receiving said valve stems, a guide rod rigidly
connected to said flange and projecting upwardly therefrom with
said bridge being slidable on said guide rod, and removable means
engaged on said flange for maintaining said flange on said cylinder
head against movement, said cylinder head having a locating recess
on the top surface thereof, and said guide rod projecting through
said flange and received in said locating recess.
Description
This invention relates to a valve mechanism for an internal
combustion engine of the type having a rocker arm pivotally mounted
on a rocker shaft, a cylinder head, a guide rod mounted on the
cylinder head, a bridge having arms and slidably mounted on the
guide rod so as to be urged by the movement of the rocker arm, a
plurality of valves each stem of which is connected with respective
arm of the bridge, said stem being urged downwardly by the movement
of the bridge and upwardly by a valve spring through a guide sleeve
fixed to and passed through the cylinder head. More specifically
the present invention concerns a guide device for guiding the
up-and-down movement of the bridge in such a valve mechanism.
In the internal combustion engines of the type described herein,
the valve stem is connected with the arm of the bridge capable of
moving up and down vertically along the guide rod, and the rocking
motion of the rocker arm is transmitted to said bridge to similarly
move the valve stems in order to open and close the respective
ports in the combustion chamber.
If the guide rod should be improperly positioned when assembling
the engine or if loose motion should develop in the movement of the
bridge during service, the valve stems would move erratically and
thus would interfere with the proper valve timing. It is therefore
highly essential that the guide device is to be so designed as to
prevent occurrence of such erratic bridge movement and that utmost
care should be exercised in installing the bridge guiding
members.
The internal combustion engine construction is generally such that
the guide rods must be mounted on the cylinder head. In
conventional guide devices, guide rods are either force or press
fitted directly into the cylinder head or rigidly fitted to flanges
and secured by welding, bolting or likewise jointing the flanges to
the cylinder head.
Where the guide rod is designed for direct press fitting, the
fitting or mating parts must be machined to much closer tolerances
and this requirement calls for stricter dimensional control in
manufacturing. Moreover, such a direct press fitted connection is
liable, in the course of service, to develop rattle and resultant
water leakage because the connection is subject to large stresses
necessarily set up therein during operation. When a rattling
condition has developed in the guide device, the cylinder head must
be immediately be replaced or a secondary mechanical trouble may
develop to damage the engine beyond repair. In either case,
replacement of a guide rod that has worn down to the limit due to
sliding guide action entails a cumbersome and often complicated
procedure.
In order to avoid the above-mentioned drawback of conventional
guide devices, I propose to hold down the flange, with which the
guide rod is rigidly connected, to the cylinder head by manner that
is basically different from the conventional manners, that is
without using an exclusive means of securing the flange direct to
the cylinder head.
According to a feature of this invention, a flange rigidly fixed to
or integrally formed with the lower end of the guide rod has holes
for passing the guide sleeve in which valve stem reciprocates
guidedly and a shoulder is formed on the upper portion of the guide
sleeve, said flange being rested on the cylinder head and fastened
by the shoulders of the guide sleeves when the latter is fixed in
place in the cylinder head.
According to a further feature of this invention, a flange rigidly
fixed to or integrally formed with the lower end of the guide rod
has holes for passing the guide sleeve, said flange having annular
boss around each hole and being provided with a seat for the spring
around the boss, and said flange being rested on the cylinder head
and fastened thereto only by the action of the valve spring.
Therefore the action of the valve spring is utilized to push down
on the flange to hold it against the cylinder head.
Even where a flange according to this invention is used as a means
of securing the guide rod to the cylinder head, strict dimensional
accuracy is no less required, and added caution has to be
exercised, at the time of securing the flange to the cylinder head,
to preserve the original shapes of various related parts.
Furthermore, the guide device to secured to the cylinder head is
not free from the drawback mentioned above.
To illustrate this invention in detail, attention is directed to
the embodiments thereof shown in the attached drawings, in
which:
FIG. 1 is a side view mainly in section of a portion of an internal
combustion engine according to an embodiment of this invention,
showing a guide device as mounted in place;
FIG. 2 is a perspective view of a flange and a guide rod according
to the invention, having a recessed seat with a hole at each flange
end;
FIG. 3 is a view similar to FIG. 2, showing a modification of the
embodiment of FIG. 2;
FIG. 4 is a view similar to FIG. 2, showing another modification of
the embodiment of FIG. 2;
FIG. 5 is a side view in section, exemplifying a manner of securing
to the cylinder head the flange shown in FIGS. 3 or 4;
FIG. 6 is a view similar to FIG. 5, illustrating a manner of
locating the guide rod with respect to associated parts according
to the invention.
FIG. 7 is a side view mainly in section of a portion of an internal
combustion engine according to another embodiment of the present
invention.
FIG. 8 is a perspective view of a flange and a guide rod similar to
those of FIG. 2 but constituting another embodiment of the
invention, having an annular boss around the hole in each seat
portion of the flange; and
FIG. 9 is a view similar to FIG. 6, showing a manner of mounting
the flange shown in FIG. 8 on the cylinder head.
Similar numerals refer to similar parts throughout the several
drawings.
Referring to FIG. 1, a rocker arm 1 is pivotally mounted on a
rocker shaft 2 and is capable of rocking motion around the axis of
the shaft 2 as actuated by a push rod 3 in a well known manner. In
the shown embodiment of internal combustion engine, two generally
identical valves 4 and 4' are employed for each rocker arm. A
bridge 5 whose ends are in the form of arms 6 and 6', moves
vertically on a guide rod 7 as guided therewith and actuated by
rocker arm 1, said guide rod 7 being located on a cylinder head 8
by a flange 9 as will be described more clearly. A valve stem 10,
adjustably connected with arm 6 by means of bolt 11 threaded into
said arm 6 and locked with nut 12 threaded to said bolt 11 in such
a manner as to provide freedom of adjustment, extends slidably in
the guide sleeve 13, which is press fitted in and passes through
the cylinder head 8, so that, as the stem 10 is caused to
reciprocate in said sleeve 13 by the rocking action of the rocker
arm 5 a valve disc 14 seats on and unseats from the valve seat 15
to close and open a port formed in a cylinder 23. The guide sleeve
13 is provided at it top end with a valve stem seal 35 in usual
manner. Near a stem end 16, where bolt 11 is threadedly engaged
with the arm 6, there is provided on the stem a groove 17 for
fittedly receiving a conical split key 18, around which is wedgedly
secured an upper seat 19 for a valve spring 20. This spring 20 will
urge the valve 4 toward its seated position.
In the cylinder head 8, an exhaust gas passage 21 and cooling water
passage 22 are formed, as well-known techniques. The other valve
41', whose stem 10' is connected as above with the other arm 6', is
associated with parts corresponding to those already mentioned of
the valve 4, and such corresponding parts are referred to by like
numerals with a superscribed prime sign ('). The valve mechanism
arrangement thus far described is conventional and comes under the
techniques of prior arts.
According to an embodiment of the invention as shown in FIG. 1, the
flange 9 is held down in place by shoulders 24 and 24' integrally
formed of guide sleeves 13 and 13' respectively, each sleeve being
press fitted into the cylinder head 8 and, if desired, secured
further to the cylinder head 8 by threading nut 25 to a threaded
lower end portion 26 of said sleeve protruding inwardly from the
head 8, as shown in the drawing, so that each shoulder 24 fastens
the flange 9 to the head 8.
The bottom end of the guide rod 7 is rigidly fitted to and
restrained in the flange 9. Welding or press fit or threaded
connection, or any combination thereof, for example, can be adopted
for securing rod 7 to flange 9; or the rod 7 and flange 9 may be
formed integral, as desired, by machining a single-piece stock.
FIGS. 2 through 6, inclusive, each show a guide device of the
invention, consisting of the guide rod and the flange. In FIG. 2,
the flange 9 has its both ends recessed to present two seats 27 for
the shoulders 24 to rest on and is provided with a centrally
positioned hole 28 in each seat 27 for passing guide sleeve 13.
In FIG. 3 wherein respective parts are distinguished by adding a
subscript letter a to each reference numeral, as necessary, the
flange 9a as a whole is in the shape of letter T, with an arm 29
extending from its midsection in the plane of the flange. The arm
29 has a centrally positioned hole 30 for passing a bolt 31, which
is threaded into the cylinder head 8 to secure said flange direct
to the head 8 as an additional securing means.
In FIG. 4 wherein respective parts are distinguished by adding a
subscript letter b to each reference numeral, as necessary, the
flange 9b as a whole is in the shape of a cross, with two arms 29b
extending from the midsection in opposite directions, each arm 29b
being similarly provided with a centrally positioned hole 30b, as
in FIG. 3, for the purpose of securing flange 9b additionally and
direct to cylinder head 8 by means of bolts 31, as will be seen in
the view in section of FIG. 5. It must be pointed out here that the
bolts 31 are auxiliary members for the flanges of FIGS. 3 and
4.
In FIG. 6, the guide rod 7 protrudes downwardly from the flange 9,
the protruding portion being indicated at 32 and fittedly received
by a recess 33 provided in cylinder head 8. The protrusion 32 and
the recess 33 in the head 8 jointly serve as a means of accurately
locating guide rod 7 in positional relationship to associated
parts.
In FIG. 7, there is shown another embodiment of this invention,
wherein corresponding parts are indicated by same reference
numerals as in FIG. 1. The illustrated embodiment is substantially
same as the embodiment shown in FIG. 1 except that the guide sleeve
13 has no shoulder 24. Therefore, the flange 9 of this device is
fixed on the cylinder by only the action of the spring 20 inserted
between the seat 27 on the flange 9 and upper seat 19. In another
words, the bottom ends of the valve springs 20 are borne by the
flange 9 to hold said flange against the cylinder head 8 by its
spring action. The flange 9 used in this embodiment is shown in
FIG. 8.
Referring to FIG. 8, which illustrates another modification of the
flange for mounting the guide rod on the cylinder head, the flange
9 is similar to that of FIG. 2, but the difference being that each
seat 27 with the hole 28 has an annular boss 34 forming an upward
extension of said hole 28 by its inside diameter, its outside
diameter being sized to fit into and thereby restrict the bottom
end of the valve spring 20 in lateral direction, such that the
flange 9 is pressed down equally at its recessed seat ends against
cylinder head 8.
The guide rod 7 shown in FIG. 8 may also protrude downwardly from
the flange 9 as illustrated in FIG. 6. Such a device is shown in
FIG. 9.
From the foregoing disclosure it will be readily seen that the
flange, with which the guide rod is integrally or rigidly
connected, is neither welded, threaded nor otherwise jointed to the
cylinder head, so that the drawback attendant on such a manner of
jointing is eliminated and that the device can be easily removed to
facilitate valve mechanism servicing. Furthermore, the force
necessary for securing the flange to the cylinder head is obtained
not by additional parts but by slightly modified regular members of
the valve mechanism; and the flange and guide rod can be accurately
located at the time of engine assembly as determined by the guide
sleeves and/or the protruding end of the guide rod.
Thus, the guide devices according to the invention are easy to
machine and fabricate and thereby improve engine production. I
experimentally used the disclosed guide devices in actual engines
only to find that they are all effective in accomplishing the
stated object and also ensuring the satisfactory and stable
performance of the valves.
It is to be understood that this invention is not limited to the
exact construction shown and described, but that various changes
and modification may be made without departing from the spirit and
scope of this invention as defined by the appended claims.
* * * * *