U.S. patent application number 11/882381 was filed with the patent office on 2007-11-22 for twin cylinder motorcycle engine.
This patent application is currently assigned to S & S Cycle, Inc.. Invention is credited to Floyd Baker, Brian Hanold, Scott Sjovall, Bruce Tessmer.
Application Number | 20070266969 11/882381 |
Document ID | / |
Family ID | 35308222 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070266969 |
Kind Code |
A1 |
Hanold; Brian ; et
al. |
November 22, 2007 |
Twin cylinder motorcycle engine
Abstract
A rocker box, pushrod assembly, oil delivery system, tappets and
tappet guides are provided for an engine, particularly a shovelhead
motorcycle engine. The rocker box includes a separable upper
portion and lower portion with a seal for sealing the upper portion
and lower portion when coupled together. The pushrod assembly
includes an adjusting unit that collapses into a pushrod shaft. The
oil delivery system includes an oil passageway(s) in a rocker shaft
of a rocker arm assembly, and at least one of an oil passageway(s)
in a rocker box and an oil passageway(s) in a pushrod assembly.
Inventors: |
Hanold; Brian; (Richland
Center, WI) ; Baker; Floyd; (Readstown, WI) ;
Tessmer; Bruce; (Richland Center, WI) ; Sjovall;
Scott; (Westby, WI) |
Correspondence
Address: |
STEPTOE & JOHNSON LLP
1330 CONNECTICUT AVENUE, N.W.
WASHINGTON
DC
20036
US
|
Assignee: |
S & S Cycle, Inc.
Viola
WI
|
Family ID: |
35308222 |
Appl. No.: |
11/882381 |
Filed: |
August 1, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10845126 |
May 14, 2004 |
|
|
|
11882381 |
Aug 1, 2007 |
|
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Current U.S.
Class: |
123/90.1 |
Current CPC
Class: |
Y10T 74/2107 20150115;
F01M 9/10 20130101; Y10T 29/49295 20150115; F01M 11/02
20130101 |
Class at
Publication: |
123/090.1 |
International
Class: |
F01L 1/14 20060101
F01L001/14 |
Claims
1.-45. (canceled)
46. A tappet guide assembly for a motorcycle engine, comprising: a
shovelhead style tappet block including: at least one pushrod
counterbore for receiving a corresponding pushrod cover; and at
least one tappet bore for receiving a corresponding evolution style
tappet; and the evolution style tappet positioned within each
tappet bore for actuating a corresponding pushrod assembly.
47. The tappet guide assembly of claim 46, further comprising at
least one 0-ring for sealing the shovelhead style tappet block with
the pushrod cover(s).
48. The tappet guide assembly of claim 46, further comprising at
least one gasket for sealing the shovelhead style tappet block with
a mounting surface on a crankcase.
49. A shovelhead motorcycle engine including the tappet guide
assembly of claim 46.
50. A motorcycle including the shovelhead motorcycle engine of
claim 49.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to rocker boxes,
pushrods, tappets, tappet guides, and oil delivery systems for
combustion engines, and more particularly to such devices as
applied to twin cylinder motorcycle engines.
[0003] 2. Description of the Related Art
[0004] Conventional rocker boxes typically involve a cast structure
with parts (e.g., rocker arms, pushrods, etc) extending into and/or
mounted within the cast structure. Due, in part, to the integral
nature of cast rocker boxes, installing, removing, and adjusting
the parts extending into and/or mounted within the cast rocker box
is difficult. As such, in many instances the entire cylinder head
and rocker box must be removed from the motorcycle in order to
access the parts positioned therein. Even after removal of the
cylinder head and rocker box, the movable parts extending into
and/or mounted within the cast rocker box are still difficult to
access.
[0005] Additionally, the cast structure of conventional shovelhead
rocker boxes tends to have a rough outer surface, which is
difficult to finish into a smooth, more aesthetically pleasing
surface. Further, this surface is particularly difficult to polish
and/or chrome plate due to inconsistencies and defects inherent in
parts produced by known casting processes. As such, it is difficult
to manufacture a rocker box with an aesthetically pleasing outer
surface.
[0006] Another exemplary rocker box is described in U.S. Pat. No.
6,296,071, which is incorporated by reference herein in its
entirety. The '071 patent includes a rocker box with a separable
rocker support for supporting a pair of rocker arms and a breather
apparatus for regulating oil blow by. This rocker support increases
the part count and complexity of the rocker box assembly, and
reduces the structural rigidity with which the rocker arms are
supported. Further, the added space for supporting the breather
apparatus needlessly increases the size of the device in motorcycle
engines which do not require a breather apparatus at all.
[0007] In addition, the '071 configuration is adapted for a pushrod
oiling application in which oil is supplied to the rocker arms via
oil passageways along the pushrods, characteristic of evolution
style motorcycle engines. Not all motorcycle engines, however, are
configured to provide oiling via the pushrods. Thus, a need exists
for an improved rocker box for motorcycle engines.
[0008] Other problems with the prior art not described above can
also be overcome using the teachings of the present invention, as
would be readily apparent to one of ordinary skill in the art after
reading this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 depicts an exploded view of a twin cylinder
shovelhead style motorcycle engine according to an embodiment of
the present invention.
[0010] FIGS. 2-7 depict exploded views of a rocker box according to
an embodiment of the present invention.
[0011] FIGS. 8A-8D depict portions of the rocker box of FIG. 2 at
different angles (including sectional views).
[0012] FIGS. 9A-9F depict views of an upper portion of the rocker
box of FIG. 2 coupled to a lower portion thereof.
[0013] FIGS. 10-14 depict enlarged views of an upper portion of the
rocker box of FIG. 2 coupled to a lower portion thereof.
[0014] FIG. 15A depicts an exploded view of an adjustable pushrod
assembly according to an embodiment of the present invention.
[0015] FIG. 15B depicts a sectional view of the adjustable pushrod
assembly of FIG. 15A.
[0016] FIGS. 16A-H depict views of a tappet guide assembly
according to an embodiment of the present invention.
[0017] FIGS. 17A-D depict views of a rocker arm assembly according
to an embodiment of the present invention.
[0018] FIG. 18 depicts a sectional view of a rocker arm assembly
including a rocker shaft positioned within a rocker arm according
to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0019] Reference will now be made in detail to exemplary
embodiments of the present invention. Wherever possible, the same
reference numbers will be used throughout the drawings to refer to
the same or like parts.
[0020] For purposes of illustration only, a twin cylinder
motorcycle engine will be used to describe various features and
aspects of the present invention. As an example, the present
invention may be used in conjunction with Harley Davidson's
Shovelhead style motorcycle engine. It should be appreciated,
however, that many embodiments of the present invention are
applicable to non-motorcycle engines and components (e.g.,
pushrods, tappet guides, etc.), to single cylinder motorcycle
engines, and to motorcycle engines having more than two cylinders.
As such, other uses for the present invention are contemplated in
addition to those described in detail below.
[0021] A twin cylinder motorcycle engine ("engine" hereafter)
according to an embodiment of the present invention is shown in the
exploded view of FIG. 1. The engine includes rocker box assemblies
100 (shown in greater detail in FIGS. 2 to 14), cylinder head
assemblies 110, and a crankcase 120. Other assemblies may also be
provided, as would be readily apparent to one of ordinary skill in
the art after reading this disclosure.
[0022] According to one embodiment of the present invention, each
of the rocker box assemblies 100 comprise a separable upper portion
5 and a lower portion 8. Preferably, the separable upper portion 5
and lower portion 8 can be coupled together so as to form an outer
housing of rocker box assemblies 100, and are split substantially
parallel to the mounting surface of the cylinder head. Alignment of
the upper portion 5 to lower portion 8 may be facilitated by one or
more dowel pins 10 (see FIG. 6), or the like. One or both of
separable upper portion 5 and lower portion 8 can be made of 6160
billet aluminum or like material, and may undergo a heat treatment
process (e.g., a T6 heat treatment process).
[0023] Additionally, the separable upper portion 5 and/or lower
portion 8 may be finished, polished, and/or chrome plated so as to
include a highly reflective and aesthetically appealing outer
surface. Finishing/machining the upper portion 5 and/or lower
portion 8 from billet aluminum allows precise control of
dimensions, which assures consistent internal clearances between
the rocker arms 6 and the upper portion 5, and between the valve
springs and the upper portion 5. This is an area of concern in
applications using high lift cams and/or oversized aftermarket
valve springs with stock cast shovelhead style boxes, which tend to
have considerable dimensional variation from part to part. Further,
precise control of external dimensions assures consistent clearance
between the upper portion 5 and the motorcycle frame (not
shown).
[0024] In order to provide an oil tight seal between the separable
upper portion 5 and lower portion 8 when coupled together, a seal
101 (e.g., a gasket type/o-ring type seal) is used as shown best in
FIG. 3. The seal 101 may be made of 70 Durometer Viton or like
material, and installed in a groove formed within one or both of
upper portion 5 and lower portion 8. Other configurations are also
contemplated.
[0025] With the oil tight seal maintained using seal 101, oil is
first distributed via a passage from the crankcase 120 to the upper
portion 5 and/or lower portion 8 of the rear rocker assembly 100
(relative to a front of the engine), such as via an oil line or the
like. Within one or both of the upper portion 5 and lower portion 8
of the rear rocker assembly 100, another oil passage 402 (FIG. 8B)
is provided so as to channel oil between the two (or more) rocker
arm assemblies positioned therein. Preferably, oil enters the rear
rocker assembly 100, and is distributed via passage 402 to an
exhaust rocker arm. At the exhaust rocker arm, oil enters via a
hole 2003 in plug 1 (see FIG. 18), and then passes into rocker
shaft oil passageway 2001. Oil may be delivered along a length of
rocker shaft 3 using rocker shaft oil passageway 2001, such as to a
rocker roller tip 1008 and ball socket 1004 via oil passageways
1002 and 1003 respectively (see FIGS. 17A-17D).
[0026] Oil then is passed from the exhaust rocker arm to the intake
rocker arm (e.g., via passage 402 or another passage).
Alternatively, oil may be passed to the intake rocker arm
simultaneous with oil delivery to the exhaust rocker arm. Oil is
delivered along a length of the intake rocker arm in a similar
manner as previously described with respect to the exhaust rocker
arm. A fitting on the upper portion 5/lower portion 8 of the rear
rocker assembly 100 may be provided to facilitate an
interconnection of an oil passage from the rear rocker box assembly
100 (e.g., the passage extending from the intake rocker) to the
front rocker box assembly 100, where oil may be distributed in a
like manner to the rocker arm assemblies positioned therein. Other
oiling applications are also contemplated.
[0027] As previously noted, movable parts are positioned within the
rocker box assemblies 100. Such movable parts may include, for
example, rocker arm assemblies comprised of rocker arms 6, rocker
shafts 3, plugs 1, and o-ring seals 13, 19. To facilitate
positioning and housing of the rocker arm assemblies, one or both
of the upper portion 5 and the lower portion 8 may include at least
two cavities 410, 420 (FIG. 8A), which may be substantially
opposite to each other about a central axis 400. Preferably, each
cavity 410, 420 has a periphery adapted to receive a corresponding
rocker arm 6 (not shown in FIG. 8A), without a separate rocker arm
supporting structure. More preferably, each cavity 410, 420
includes a substantially straight portion for receiving a rocker
shaft 3, and side portions for receiving pushrod assemblies 130
(FIG. 15) and for actuating valves (not shown). Additional
cavities, holes, etc. may also be provided.
[0028] As previously noted, according to one embodiment of the
present invention a rocker arm assembly comprises a rocker arm 6
with rocker shaft 3 coupled thereto--see rocker arm counter bore
1007 and threaded rocker shaft counter bore 2002 with bushings
1005, 1006 in FIG. 17B and FIG. 18. The threaded rocker shaft
counter bore 2002 preferably is threaded to receive a
sealing/oiling plug 1. Installed in grooves o-rings 13, 19 are
provided for sealing plug 1 and rocker shaft 3 in upper portion 5.
Preferably, o-ring 13 is installed in a groove of plug 1, and
o-ring 19 is installed in a groove of upper portion 5. O-ring 13
may be further received in a counter/main bore of upper portion
5/lower portion 8 for sealing oil delivery passages therein. As
with seal 101, o-rings 13, 19 may be made of 70 Durometer Viton or
like material.
[0029] Preferably, each rocker arm 6 receives a rocker shaft 3 with
one or more notches 2000 for orienting the rocker shaft 3 against
shoulder screws/bolts 7. In particular, these rocker shafts 3 may
be pre-loaded against the shoulder screws/bolts 7 using plugs 1,
thereby preventing unintentional movement of the shafts 3 and
facilitating easy removal of the shafts 3 from the rocker arm
assemblies and/or rocker box assemblies 100 (e.g., using about a
1/4'' Allen socket). Other mounting techniques are also
contemplated, including dowel pins 10 which help locate the upper
portion 5/lower portion 8 relative to one another.
[0030] According to one aspect of the present invention, the plug 1
is made of a heat treated (RC 33-37) 416 stainless steel, which can
be readily polished and is corrosion resistant. Additionally, the
rocker shafts 3 may be made of a different material, such as 8620
steel. Other materials are also contemplated.
[0031] Preferably, the shafts 3 are substantially straight as shown
best in FIGS. 2-7, and comprise a single, integral piece. Using a
straight shaft 3 which is separable from the rocker arm 6 can be a
significant cost savings over other possible configurations, due to
the elimination of complex rocker shaft assemblies and
configurations and corresponding reduction in manufacturing costs.
Further, the straight shaft 3 configuration reduces the number of
holes required in the rocker box assembly 100 for positioning a
rocker arm assembly therein, which, in turn, reduces the potential
for oil leaks, and increases the strength of the rocker box
assembly 100. Other advantages will also be observed through
practice of the present invention.
[0032] According to another embodiment of the present invention as
shown best in FIGS. 15A and 15B, collapsible pushrod assemblies 130
are provided. The pushrod assemblies 130 are designed to project
into the rocker box assemblies 100 for actuating the rocker arms 6,
and are preferably received with ball sockets 2005, 2006 at each
end. Each pair of pushrod assemblies 130 may be actuated by tappets
3000, 3001 (FIG. 16E) in the engine, the actuated pushrod
assemblies 130 causing corresponding rocker arms 6 to rotate about
a central axis thereof, thereby actuating a valve (exhaust or
intake) via a roller tip 1008 or the like (FIG. 17B) on the rocker
arm 6. In this regard, the rocker arms 6 are preferably machined
and/or forged to maintain a ratio of about 1.5:1 or about 1.43:1
(as examples only) to actuate the valves at a precise ratio to the
actuation of tappets 3000, 3001. According to one preferred
embodiment of the present invention, Evolution style tappets are
provided in the correct geometric orientation to actuate the
pushrod assemblies 130 in a shovelhead style engine using Evolution
style camshafts.
[0033] The pushrod assemblies 130 are preferably collapsible and
adjustable, so as to facilitate easy removal and adjustment
thereof. In particular, the pushrod assemblies 130 may each
comprise a single threaded adjusting unit that threads into a
pushrod shaft 530. In this regard the adjusting unit preferably
includes a threaded portion 510 and an unthreaded portion 520, the
unthreaded portion 520 being of smaller diameter than the threaded
portion 510. When the single threaded adjusting unit is threaded
all (or substantially all) the way into the pushrod shaft 530, the
threads are disengaged and the unthreaded portion 520 of the
adjusting unit can be slid inside the pushrod shaft 530,
significantly reducing the overall length of the pushrod assembly
130. This reduced length allows for easy installation and removal
of the pushrod assemblies 130 within the engine. As an example,
pushrod assemblies 130 provided in engines equipped with Evolution
style tappet guides and/or Evolution style cams can be
installed/removed without removal of the upper portion 5 of the
rocker box assembly 100 or the cylinder head assembly 110.
[0034] In an application where the oil is delivered via the pushrod
assemblies 130, oil is supplied to the rocker arm 6 via an oil
passageway 2007 (FIG. 15B) in the pushrod assembly 130. Such an oil
delivery technique may be performed as an alternative or in
addition to the oil delivery technique previously described in
reference to oil passageway 402 in upper portion 5/lower portion 8.
Other oil delivery techniques using pushrod assemblies 130 are also
contemplated.
[0035] A tappet guide assembly according to another embodiment of
the present invention is shown in FIGS. 16A-16H. In particular the
tappet guide assembly includes a tappet block 3003 with pushrod
cover counterbores 3006, 3007, each pushrod counterbore receiving a
corresponding pushrod cover (with a pushrod assembly 130 positioned
therein). Preferably, the pushrod counterbores 3006, 3007 are
oriented so as to be substantially parallel to the counterbores in
the rocker box assembly 100 in order to facilitate proper alignment
of the pushrod assemblies 130.
[0036] One or more pushrod cover o-rings 3004, 3005 may be provided
for sealing the tappet block 3003 to the pushrod covers, and one or
more tappet gaskets 3002 may be provided for sealing the tappet
block 3003 to a mounting surface. According to one aspect of the
present invention as shown best in FIGS. 16G and 16H, one or more
oil return passages may also be provided, the oil return passages
including channels which pass down from the pushrod cover
counterbores 3006, 3007 to below the gasket 3002 surface and
breakout therefrom. Such passages may be formed, for example, by
drilling two or more holes that intersect along a length thereof. A
receiving counterbore may also be provided for receiving the oil
from the noted channels, the receiving counterbore channeling the
oil back down to a camchest in crankcase 120. In one exemplary
configuration, the oil return passage(s) has a diameter of about
0.188'', and couple to channels having a diameter of about 0.125''
and a length of about 1.38''. Other configurations are also
contemplated.
[0037] The tappet block 3003 further includes one or more tappet
bores 3008, 3009 for receiving tappets 3000, 3001. As would be
understood by one of skill in the art, one or more camshafts
actuate tappets 3000, 3001, which actuate pushrod assemblies 130,
which actuate rocker arms 6 (via ball sockets), thereby opening and
closing valves on the top of the engine. The tappet bores 3008,
3009 are thus positioned so as to properly align the tappets 3001,
3000 with the pushrod assemblies 130 (see FIGS. 16G and 16H).
Hence, other configurations and orientations are also contemplated
to compensate for variations in engine layout, such as to align
pushrod cover counter bores for rocker arm assemblies in shovelhead
or pushrod engines, and to maintain proper oil sealing.
[0038] The tappet block 3003 preferably has a shovelhead style
configuration, but is adapted to use evolution style hydraulic
tappets 3000, 3001 and evolution style camshafts. As such, the
tappet block 3003 is preferably slightly larger than conventional
shovelhead style tappet blocks. By way of example, stock tappet
bores are typically o0.73215 whereas the enlarged tappet block 3003
of the present invention is greater than o0.73215, such as about
o0.84335 (i.e., about 15% larger). Other exemplary sizes may
include, for example, at least 5% larger, at least 10% larger, etc.
in comparison to stock parts (e.g., Harley Davidson part no.
18522-53A). In addition to providing greater functionality, the
enlarged size further has better wear characteristics than
conventional devices.
[0039] Preferably, the tappet guide assembly is machined from a
billet aluminum base material, which provides high dimensional
accuracy and a consistent polishing and chrome plating.
Alternatively, one or more of the tappet guide assembly parts may
be cast from aluminum, steel or a like material.
[0040] The foregoing description of various embodiments of the
invention has been presented for purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise form disclosed, and modifications and
variations are possible in light of the above teachings or may be
acquired from practice of the invention. The embodiments were
chosen and described in order to explain the principles of the
invention and its practical application to enable one skilled in
the art to utilize the invention in various embodiments and with
various modifications as are suited to the particular use
contemplated.
* * * * *