U.S. patent application number 11/277417 was filed with the patent office on 2006-07-20 for method of making a rocker arm.
This patent application is currently assigned to GenTek Technologies Marketing, Inc.. Invention is credited to Dan Mills, Scott P. Smith.
Application Number | 20060157013 11/277417 |
Document ID | / |
Family ID | 36682562 |
Filed Date | 2006-07-20 |
United States Patent
Application |
20060157013 |
Kind Code |
A1 |
Smith; Scott P. ; et
al. |
July 20, 2006 |
METHOD OF MAKING A ROCKER ARM
Abstract
A method of making a rocker arm is provided that includes the
integration, into a single piece, of three separate parts namely, a
central longitudinal member, a push-rod plate; and a valve end
plate in which the push-rod plate and the valve end plate are
secured to opposing ends of the central member to create the
integrated rocker arm.
Inventors: |
Smith; Scott P.;
(Temperance, MI) ; Mills; Dan; (Maumee,
OH) |
Correspondence
Address: |
GENERAL CHEMICAL PERFORMANCE PRODUCTS LLC.
90 EAST HALSEY ROAD
PARSIPPANY
NJ
07054
US
|
Assignee: |
GenTek Technologies Marketing,
Inc.
Parsippany
NJ
07054
|
Family ID: |
36682562 |
Appl. No.: |
11/277417 |
Filed: |
March 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10953952 |
Sep 29, 2004 |
|
|
|
11277417 |
Mar 24, 2006 |
|
|
|
Current U.S.
Class: |
123/90.39 |
Current CPC
Class: |
F01L 2301/00 20200501;
F01L 1/181 20130101; F01L 2303/00 20200501; F01L 1/146
20130101 |
Class at
Publication: |
123/090.39 |
International
Class: |
F01L 1/18 20060101
F01L001/18 |
Claims
1. A method of making an integrated rocker arm comprising joining
separate parts including: a central longitudinal member; a push-rod
plate; and a valve plate to form a unitary member wherein said
push-rod plate and said valve plate are integrally secured to
opposing ends of said central member.
2. The method of claim 1 wherein said central member, said push-rod
plate, and said valve plate comprise a metallic material.
3. The method of claim 1 wherein said central member is
cylindrical.
4. The method of claim 2 wherein said metallic material comprises
aluminum alloy.
5. The method of claim 2 wherein said metallic material comprises a
steel alloy.
6. The method of claim 1 wherein said push-rod plate and said valve
plate are welded to said central member.
7. The method of claim 1 where said push-rod plate and said valve
plate are pulse welded to said central member.
8. The method of claim 1 wherein said push-rod plate and said valve
plate are laser welded to said central member
9. The method of claim 1 wherein said push-rod plate and said valve
plate are staked to said central member.
10. The method of claim 1 wherein said push-rod plate and said
valve plate are brazed to said central member.
11. An cylinder valve assembly, comprising: I. an inlet valve
assembly including a rocker arm formed by the method of claim 1; a
tappet configured to contact a rotating cam; a push rod coupled to
said tappet and the push rod plate of the rocker arm; and a valve
coupled to the valve plate of said rocker arm, and II. an exhaust
valve assembly including a rocker arm formed by the method of claim
1; a tappet configured to contact a rotating cam; a push rod
coupled to said tappet and the push rod plate of said rocker arm;
and a valve coupled to the valve plate of said rocker arm.
12. The assembly of claim 10 wherein said push-rod plate and said
valve plate of said inlet valve assembly and said push-rod plate
and said valve plate of said exhaust valve assembly are
substantially similar.
Description
TECHNICAL FIELD
[0001] This application is a continuation-in-part of application
Ser. No. 10/953,952, filed Sep. 29, 2004.
[0002] The present invention relates to rocker arm assemblies for
internal combustion engines and, in particular, to rocker arms
constructed by combining three discrete parts to form an integrated
rocker arm composite and to the method for making the rocker arm.
The rocker arm assemblies of the present invention have efficient
unique lubrication systems and also permit both a bearingless and a
roller bearing type rocker arm shaft assembly to be interchangeably
mounted in a same engine.
BACKGROUND OF THE INVENTION
[0003] Rocker arm assemblies are utilized in internal combustion
engines for actuating intake and exhaust valves. As an engine cam
shaft rotates, a push rod is selectively actuated by cam lobes
located on the cam shaft and the push rod, in turn, directs an
upward force on one end of a rocker arm to cause the rocker arm to
pivot about a mounting shaft. As the rocker arm pivots, its
opposite end generates a downward force to selectively open an
intake or exhaust engine valve.
[0004] Typically, rocker arms are integral one-piece parts having a
generally U-shaped cross-section including a pair of opposing side
walls separated by a bottom wall and a pair of end walls disposed
between the side walls. In the prior art, rocker arms are
conventionally cast as an integral piece. The cast piece is then
machined as necessary to form the rocker arm to its final
dimensions. This prior art process requires separate tooling to
produce each intake and exhaust component and is often time
consuming and/or expensive.
[0005] Accordingly, a need exists for a more expeditious and less
costly method for the production of rocker arms.
SUMMARY OF THE INVENTION
[0006] According to the invention, a novel means for the production
of a rocker arm that includes a push-rod plate at one end, a valve
plate at the opposite end, and a longitudinal central member
between the two ends is provided. The length of the central member,
preferably a cylindrical member, and the angle of rotation between
the push-rod plate end and the valve plate end of the rocker arm
may each be varied such that the rocker arm may be adapted for use
with many different cylinder valve assemblies.
[0007] More specifically, the method of the invention provides for
the rapid formation of a rocker arm by making discrete parts such
as by stamping and then integrating the parts such as by welding or
brazing techniques, as distinguished from casting the unit with its
parts as a whole. The method of the invention provides for adapting
the rocker arm for use with many different cylinder valve
assemblies utilizing the same basic tooling configurations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The features and inventive aspects of the present invention
will become more apparent upon reading the following detailed
description, claims, and drawings, of which the following is a
brief description:
[0009] FIG. 1 is a partial perspective view of an exemplary
cylinder valve assembly.
[0010] FIG. 2 is an isolated view of an inlet valve assembly of the
cylinder valve assembly of FIG. 1
[0011] FIG. 3 is a perspective view of three component parts that
comprise a typical rocker arm according to the invention.
[0012] FIG. 4A is a top view of an exemplary rocker arm.
[0013] FIG. 4B is a front side view of the rocker arm shown in FIG.
3A.
[0014] FIG. 5 is a flowchart illustrating an exemplary method of
forming a rocker arm.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] A rocker arm is described herein for use as part of an
engine cylinder assembly. The rocker arm is coupled to push rods
and valves for opening and closing the intake and exhaust valves of
an engine cylinder. The rocker arm includes a push-rod plate and a
valve plate each secured to opposite ends of a tubular member. The
push rod socket end and the valve pad end are separated by the
linear distance of the tubular member. The push-rod plate and valve
pad plate may be formed using a rapid formation process, such as
stamping. Thereafter, these respective plates are secured to the
appropriate end of the tubular member using well known techniques,
such as brazing or welding to form an integrated unit. As used
herein, the term integrated unit is intended to connote the
assembly of the separate or distinct members, i.e., the two end
plates to the central member, to form a unitary structure by
suitable means such that the assembly is essentially equivalent to
a member that is created initially as an integral unit.
[0016] A configuration fabricated in this manner reduces the time
and complexity involved in forming the rocker arm by known
conventional methods such as by casting and machining to the
discrete final form, the rocker arm with integrally cast push
socket end plate and valve pad end plate. Accordingly, the
invention provides for the joining of the three separate parts
substantially reduces the cost of forming the rocker arm. Further,
the length of the tubular member used in making the rocker arm can
be readily selected to vary the linear distance between the
push-rod plates and the valve plates and as a consequence, the
resulting rocker arm may be adapted for a variety of valve
configurations and angles. In addition, the push-rod end plates and
valve end plates may be used for both air inlet and exhaust valve
applications, thereby reducing the total number of unique parts
used in a cylinder valve assembly and lowering the cost of such an
assembly.
[0017] In the following description, for purposes of illustrative
explanation, numerous specific details are set forth in order to
provide a thorough understanding of the present method and
apparatus. It will be apparent, however, to one skilled in the art
that the present method and apparatus may be practiced without
various of these specific details. Reference in the specification
to "one embodiment" or "an embodiment" means that a particular
feature, structure, or characteristic described in connection with
the embodiment is included in at least one embodiment. The
appearance of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment.
[0018] Referring to the drawing, FIG. 1 illustrates a partial view
of a cylinder valve assembly 100. The cylinder valve assembly 100
is configured to control the flow of fuel into an engine cylinder
and to control the flow of exhaust out of the engine cylinder. The
cylinder valve assembly 100 generally includes a rocker arm 105, an
inlet valve assembly 110 and an exhaust valve assembly 115, each
coupled to lobed cams 120-1, 120-2.
[0019] Each rocker arm 105 includes a push-rod plate 130 and a
valve plate 135 each coupled to either of opposite ends of a
cylindrical or tubular member 140. Each rocker arm 105 is supported
by central support shafts 140. The configuration of the rocker arm
will be described in more specific detail with reference to FIGS.
3A-3B. The operation of the cylinder valve assembly 100 will first
be discussed more particularly to provide context for the function
of the rocker arm 105, beginning with the operation of the inlet
valve assembly 110 and followed by the exhaust valve assembly
115.
[0020] As previously mentioned, the inlet valve assembly 110
includes a rocker arm 105 supported by a central support shaft 145.
The push-rod plate 130 is coupled to a push rod 150 and tappet 155,
which in turn are in contact with the lobed cam 120-1. A
conventional biasing mechanism, which is not shown, maintains the
tappet 155 in contact with the lobed cam 120-1.
[0021] Preferably, the push rod 150 is hollow and provides
lubrication to a push-rod socket (not shown) for reducing wear
caused by friction. Alternatively, if a solid push rod is utilized,
then a mechanism for lubricating the interface may also be
included. FIG. 2 illustrates a side view of an inlet valve assembly
110. The lobed cam 120-1 is coupled to a cam shaft such that when
the cam shaft rotates, the lobed cam 120-1 rotates. The profile of
the lobed cam 120-1 includes lobed profile portion and a constant
radius profile portion. As the lobed cam 120-1 rotates, the tappet
profiles the profile of the lobed portion. As a result, when the
lobed cam 120-1 rotates the tappet 155 follows the profile of the
lobed portion profile.
[0022] As the tappet 155 comes into contact with the lobed portion
of the cam 120-1, the push rod 150 is moved upwardly. This motion
of the push rod 150 causes the entire rocker arm 105 to rotate. In
this instance, the rocker arm 105, including the valve plate 135
rotates, i.e., moves in the counter-clockwise direction. The valve
plate 135 is coupled to an inlet valve 160. As the valve plate 135
rotates counter-clockwise, the valve 160 is moved to an open
position. Accordingly, the push rod (130) moves upwardly in
response to the rotation of the lobed cam 120-1.
[0023] The continued rotation of the lobed cam 120-1 causes the
tappet 155 to move from contact with the lobed profile portion of
the lobed cam 120-1 to contact with the constant radius profile
portion. As a result, the push rod 150 falls, thereby causing the
rocker arm 105 to rotate in the opposite direction, or clockwise.
As the rocker arm 105 rotates in a clockwise direction, the valve
160 is moved to a closed position.
[0024] The exhaust valve assembly 115 is also in contact with a
lobed cam 120-2 such that the exhaust valve assembly 115 operates
in a similar fashion to the inlet valve assembly 110 to move an
exhaust valve 165 (FIG. 1) between an open and closed position. The
lobed cam 120-2 of the exhaust valve assembly 115 lags behind the
lobed cam 120-1 of the inlet valve assembly 110 with respect to
rotation.
[0025] The rocker arm 105, the make up of which is discussed above,
reduces the cost of a cylinder valve assembly 100 because the
rocker arm 105 may be more expeditiously formed. Further, multiple
rocker arms 105 may be used with each cylinder valve assembly 100.
In addition, the configuration of the rocker arm 105 may be readily
adapted for use with a variety of cylinder valve assemblies. One
exemplary configuration will now be discussed in more detail.
[0026] Shown in FIG. 3 is a typical perspective representation of
the components which are readily available either as stock items
such as the central element 140, or are readily fabricated by known
means such as by stamping the parts 130 and 135 and securing them
conventionally such as by welding to provide the desired rocker
arm.
[0027] In addition, the cylindrical member 140 is of a length
adapted to accurately position the rocker arm 105 with an adjacent
push rod and engine valve. By varying the angle of the push-rod
plate 130 relative to the length of cylindrical member 140, the
rocker arm 105 may be designed to precisely engage valves in almost
any engine geometry layout, including offset valves. This angle may
be controlled easily during the formation of the rocker arm 105, as
may also be the length of the cylindrical member 140.
[0028] Referring to FIGS. 4A-4B the rocker arm 105 includes a
push-rod plate 130, a valve plate 135, and a cylindrical section
140. The push-rod plate 130 will be described first, followed by a
discussion of the valve plate 135 and the cylindrical section
140.
[0029] As shown in FIG. 4A, the push-rod plate 130 includes a push
rod contact end 300 that includes a lower edge 305 having a
generally hollow semi-spherical recess formed therein such that a
generally hemispherical outer projection is formed on the push-rod
plate 130. The hemispherical recess is adapted to receive an end of
a push rod as discussed above with reference to FIGS. 1-2. The
valve plate 135 has a valve contact end 310 that includes a lower
edge 315 that preferably has a convex valve contact surface, but
may be formed with other suitable surface for contacting an end of
a valve as discussed with reference to FIGS. 1-2.
[0030] The relative orientation of the push rod contact end 300 and
the valve contact end 310 depends, at least in part, on the angle
of rotation between the push rod contact end 300 and the valve
contact end 310 and on the length of the cylindrical member 140.
The angle of rotation between the valve contact end 300 and the
valve contact end 310 may be varied by rotating the position of the
push-rod plate 130 relative to the valve plate 135 during the
formation of the rocker arm 105.
[0031] One exemplary method of forming a rocker arm will now be
described in reference to the flow diagram of FIG. 5. The method is
initiated by the forming the elemental components of the rocker arm
including (1) forming a push-rod plate (Step 400); (2) forming a
valve plate (Step 410); and (3) forming or selecting a central,
preferably, cylindrical member (Step 420). Each of these components
may be and is preferably made of a metallic material, including,
without limitation, steel alloys and aluminum alloys, although the
use of environmentally suitable plastic compositions may also be
suitable.
[0032] The push-rod plates and valve plates may be rapidly formed
as separate members by a stamping operation or other suitable
methods. The use of a stamping operation in forming the push-rod
plates and valve plates decrease the time of forming the plates, as
compared to the use of a casting operation.
[0033] The rocker arm also includes a suitable central member
which, for convenience because of ready availability, is preferably
cylindrical member. The cylindrical member (Step 420) may be formed
using known techniques, such as by extrusion or other suitable
techniques or by using suitable available stock tubular
members.
[0034] Once the components (Steps 400-420) of the rocker arm have
been formed, the relative orientation of each of the components is
then determined. In particular, the length of the cylindrical
member is determined and formed or cut to the desired predetermined
length. The length of cylindrical member affects, at least in part,
the linear or axial distance that the push-rod plate and valve
plate are separated from one another. This distance is relative to
the interaction between the given cylinder valves and push-rods.
For example, one linear or axial distance may be required for the
rocker arm to operate properly with a cylinder valve assembly while
a longer or shorter axial or linear distance may be required for
proper operation of the rocker arm in another cylinder valve
assembly. The separate three-part configuration of the rocker arm
of the invention, because of the variety of the central member,
allows the linear or axial offset to the rocker arm to be readily
adapted for operation with any number of cylinder valve assemblies.
Moreover, as discussed hereafter, the angle of rotation between the
push-rod plate and the valve plate may also be readily varied for
operation in any number of cylinder valve assemblies.
[0035] When the desired angle of rotation (Step 450) between the
push-rod plate and the valve plate is determined, this angle of
rotation between the push-rod plate and the valve plate, and in
particular between the push rod socket and the valve pad, may then
be varied accordingly to allow the rocker arm to be used in any
number of cylinder valve assemblies. In other words, once the
desired angle of rotation (Step 450) has been selected, the
push-rod plate and valve end plate are oriented with respect to
each other according to the selected angle of rotation (Step 460).
Thereafter, the push-rod plate and valve plate are each secured to
the cylindrical member (Step 470).
[0036] Some methods which may be used to attach the push-rod plate
and valve plate to the cylindrical member to form an integrated
unit, include, without limitation, the conventional means such as
welding, brazing, staking, laser welding, and other suitable known
means. Welding, staking, or brazing are relative rapid, efficient
and are preferable operations that are applicable in reducing the
cost of forming the rocker arm assembly of the invention. The use
of pulse welding is particularly preferable as a rapid and
efficient mode for attaching the push-rod and valve plates to the
respective opposite ends of the elongated central member.
[0037] The method of the present invention allows a variety of
rocker arms to be formed using the same basic tooling
configurations. In particular, as previously discussed, the
push-rod plate and the valve plate may be each be used with many
different cylinder valve assemblies by varying the relative angle
of rotation between them and by selecting the desired length of the
longitudinal central piece, e.g., the cylindrical member used in
creating the rocker arm.
[0038] Accordingly, it is seen that the method of the present
invention provides for the formation of a rocker arm by integrating
three separate pieces that include a central member, push-rod plate
at one end, and a valve end plate at the opposite end of the
central member. The method of the invention also provides for the
formation of a rocker arm that is readily adapted for use with a
variety of cylinder valve assemblies. Further, the method of the
present invention provides for the rapid formation of rocker arms,
which substantially reduces the cost of cylinder valve assemblies
and engines.
[0039] It is thus seen that a method for creating a rocker arm has
been described herein that includes a push-rod plate, a valve
plate, and a central longitudinal, preferably cylindrical, member.
The length of the central member and the angle of rotation between
the push-rod plate and the central member may be each varied such
that the rocker arm may be adapted for use with many different
cylinder valve assemblies. Additionally, the method herein
described for forming a rocker arm facilitates the expeditious
construction of rocker arms with precision dimensions using
relatively inexpensive and efficient techniques such as stamping
the push rod end and valve end plates and welding and/or brazing
the parts to form the desired integrated rocker arm. The method of
the present invention it is seen provides for adapting the thus
formed rocker arms for use with many different cylinder valve
assemblies using the same basic tooling configurations.
[0040] The invention has been described in such detail as to
illustrate the essence of the applicable method. The description
provided is not intended to be exhaustive or to limit the
disclosure to any precise form disclosed. It is apparent that many
modifications and variations are possible in light of the above
teaching. Accordingly, it is intended that the invention is to be
limited only by the scope of the following claims.
* * * * *