U.S. patent application number 11/875176 was filed with the patent office on 2008-02-28 for split type connecting rod.
This patent application is currently assigned to YAMAHA HATSUDOKI KABUSHIKI KAISHA. Invention is credited to Tsuneo ISOBE, Shinya IWASAKI, Satoshi KIKUCHI, Tsuyoshi KUBOTA, Akitoshi NAKAJIMA.
Application Number | 20080047393 11/875176 |
Document ID | / |
Family ID | 32473741 |
Filed Date | 2008-02-28 |
United States Patent
Application |
20080047393 |
Kind Code |
A1 |
NAKAJIMA; Akitoshi ; et
al. |
February 28, 2008 |
SPLIT TYPE CONNECTING ROD
Abstract
A split type connecting rod has a simple structure that is
capable of suppressing rotation of a metal bearing, and avoiding
problems such as burning. The split type connecting rod holds a
crank-pin through a metal bearing which has locking lugs. A bearing
locking groove locks at least one of the locking lugs when the
metal bearing rotates forward in the circumferential direction of a
crank-pin hole. A bearing locking groove locks at least one of the
locking lugs when the metal bearing rotates backward. The bearing
locking grooves are deviated from each other in the circumferential
direction.
Inventors: |
NAKAJIMA; Akitoshi;
(Shizuoka, JP) ; KIKUCHI; Satoshi; (Shizuoka,
JP) ; KUBOTA; Tsuyoshi; (Shizuoka, JP) ;
ISOBE; Tsuneo; (Shizuoka, JP) ; IWASAKI; Shinya;
(Shizuoka, JP) |
Correspondence
Address: |
YAMAHA HATSUDOKI KABUSHIKI KAISHA;C/O KEATING & BENNETT, LLP
8180 GREENSBORO DRIVE
SUITE 850
MCLEAN
VA
22102
US
|
Assignee: |
YAMAHA HATSUDOKI KABUSHIKI
KAISHA
2500 Shingai
Iwata-shi
JP
438-8501
|
Family ID: |
32473741 |
Appl. No.: |
11/875176 |
Filed: |
October 19, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10743457 |
Dec 23, 2003 |
7299716 |
|
|
11875176 |
Oct 19, 2007 |
|
|
|
Current U.S.
Class: |
74/593 ;
384/294 |
Current CPC
Class: |
F16C 7/023 20130101;
F16C 41/008 20130101; Y10T 74/2159 20150115; Y10T 74/216 20150115;
F16C 33/08 20130101; Y10S 384/906 20130101; F16C 9/045
20130101 |
Class at
Publication: |
074/593 ;
384/294 |
International
Class: |
F16C 7/02 20060101
F16C007/02; F16C 9/04 20060101 F16C009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 26, 2002 |
JP |
2002-378020 |
Sep 8, 2003 |
JP |
2003-315615 |
Claims
1. A split connecting rod that holds a crank-pin through a bearing
having a first protrusion and a second protrusion, comprising: a
first locking groove that locks the first protrusion of said
bearing when said bearing rotates forward in a circumferential
direction of a crank-pin hole; a second locking groove that locks
the second protrusion of said bearing when said bearing rotates
backward in the circumferential direction of the crank-pin hole;
wherein the split connecting rod includes only the first locking
groove and the second locking groove on a first side of the
crank-pin hole and no locking grooves on a second side of the
crank-pin hole.
2. The split connecting rod according to claim 1, further
comprising a large end portion including a rod portion and a cap
portion, wherein said first locking groove and said second locking
groove are arranged to extend over both of the rod portion and the
cap portion when a large end portion is fractured and split into
said rod portion and said cap portion, said first locking groove
being deviated to said rod portion side and said second locking
groove is deviated to said cap portion side.
3. The split connecting rod according to claim 1, wherein when said
bearing is split, said first protrusion locked by said first
locking groove and said second protrusion locked by said second
locking groove are arranged separately on separate portions of said
bearing that has been split.
4. The split connecting rod according to claim 1, wherein the
bearing is substantially ring-shaped and disposed on an inner
circumferential surface of the crank-pin hole.
5. The split connecting rod according to claim 1, wherein the
bearing includes a rod portion and a cap portion which are divided
along a splitting line of said bearing.
6. The split connecting rod according to claim 1, wherein the first
and second locking grooves are substantially arc-shaped.
7. The split connecting rod according to claim 1, wherein the first
and second locking grooves are arranged to prevent the bearing from
moving in said circumferential direction.
8. The split connecting rod according to claim 1, wherein the first
locking groove and the second locking groove are arranged inwardly
from an edge of the crank-pin hole in an axial direction of the
crank-pin hole.
9. The split connecting rod according to claim 1, wherein the first
and second locking grooves are arranged to prevent the bearing from
moving in an axial direction of the crank-pin hole.
Description
[0001] This application is a Divisional Application of U.S. patent
application Ser. No. 10/743,457 filed Dec. 23, 2003, currently
pending.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a split type connecting
rod, and more particularly, to a split type connecting rod with a
bearing located inside of a crank-pin hole.
[0004] 2. Description of the Related Art
[0005] A split type connecting rod is formed such that a large end
portion is fractured and divided into a rod portion and a cap
portion along a splitting plane including the shaft center of a
crank-pin hole, and the rod portion and the cap portion are coupled
by coupling bolts, and a metal bearing is generally located on the
inner circumferential surface of the crank-pin hole.
[0006] In general, this metal bearing has been split into a
rod-side portion and a cap-side portion along the splitting plane
and when such a split type metal bearing is disposed within the
inner circumferential surface of the crank-pinhole, a bearing
locking groove is formed in the inner circumferential surface so to
extend in the circumferential direction so that a locking lug
protruding from the rear surface (outer circumferential surface) of
the metal bearing is locked by the bearing locking groove in order
to determine a position of the metal bearing (e.g., see the
Unexamined Japanese Patent Publication No. HEI 6-74237).
[0007] However, the conventional split type connecting rod has a
problem in that the metal bearing is easily rotated in the
circumferential direction by an external force, and in order to
prevent burning caused by this problem, a reliable lubrication
structure is required. In particular, a motorcycle engine which
tends to be used at high speed revolutions has a problem in that a
large amount of deformation occurs at the large end portion and the
amount of rotation of the metal bearing is likely to increase
accordingly.
SUMMARY OF THE INVENTION
[0008] In order to overcome the problems described above, preferred
embodiments of the present invention provide a split type
connecting rod with a simple structure that is capable of
suppressing rotation of the metal bearing and reliably prevents
problems such as burning.
[0009] According to a preferred embodiment of the present
invention, a split type connecting rod that holds a crank-pin
through a bearing having a first protrusion and a second
protrusion, includes a first locking groove that locks the first
protrusion of the bearing when the bearing rotates forward in a
circumferential direction of the crank-pin hole, and a second
locking groove that locks the second protrusion of the bearing when
the bearing rotates backward in the circumferential direction of
the crank-pin hole, wherein the first locking groove and the second
locking groove are deviated from each other in the circumferential
direction.
[0010] The split type connecting rod includes a small end portion
and a large end portion, the large end portion includes a rod
portion and a cap portion, wherein the first locking groove and the
second locking groove are arranged to extend over both the rod
portion and the cap portion when the large end portion is fractured
and split into the rod portion and the cap portion. When this
happens, the first locking groove is preferably deviated to the rod
portion side and the second locking groove is preferably deviated
to the cap portion side.
[0011] When the bearing is split as described above, the first
protrusion locked by the first locking groove and the second
protrusion locked by the second locking groove are arranged
separately on separate portions of the bearing that has been
split.
[0012] It is preferred that the bearing is substantially
ring-shaped and disposed on an inner circumferential surface of the
crank-pin hole.
[0013] The first and second locking grooves are preferably
substantially arc-shaped.
[0014] In addition, the first and second protrusions are preferably
locking lugs.
[0015] The first and second locking grooves are preferably arranged
to prevent the bearing from moving in the circumferential
direction.
[0016] In one preferred embodiment of the present invention, the
bearing of the split type connecting rod includes a rod portion and
a cap portion which are divided along a splitting line of the
bearing, and at least two of the first locking grooves are provided
on a first side of the splitting line and at least two of the
second locking grooves are provided on a second side of the
splitting line.
[0017] It is also preferred that a valley is formed on the inner
circumferential surface of the crank-pin hole and that the valley
includes a base portion.
[0018] It is also preferred that a fracture starting point groove
is formed at the base portion of the valley, such that a width of
the fracture starting point groove is less than a width of the
valley.
[0019] It is further preferred that the split type connecting rod
is a nut-less type of connecting rod that is made of one of a
forged material, a cast material and a sintered material.
[0020] As described above, the split type connecting rod includes a
small end portion and a large end portion, and the large end
portion includes the valley and the fracture starting point groove
is formed in the large end portion.
[0021] In another preferred embodiment of the present invention, a
pair of the fracture starting point grooves are formed on the inner
circumferential surface of the crank-pin hole.
[0022] It is also preferred that the valley includes a pair of
sloped portions which define chamfers for guiding the bearing and
preferably have curved shapes or swelled, rounded shapes, or have a
concave or rectilinear shape in an upper corner thereof.
[0023] According to yet another preferred embodiment of the present
invention, an engine includes a split type connecting rod according
to any of the various preferred embodiments described above.
[0024] According to a further preferred embodiment of the present
invention, a vehicle includes a split type connecting rod according
to any of the various preferred embodiments described above.
[0025] Other features, elements, characteristics and advantages of
the present invention will become more apparent from the following
detailed description of preferred embodiments of the present
invention.
[0026] Other features, elements, steps, characteristics and
advantages of the present invention will become more apparent from
the following detailed description of the preferred embodiments
thereof with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a front view of a split type connecting rod
according to a first preferred embodiment of the present
invention;
[0028] FIG. 2 is a cross-sectional view of a large end portion of
the split type connecting rod of the first preferred embodiment of
the present invention;
[0029] FIG. 3A is an enlarged view of a fracture starting point
groove of the large end portion for illustrating the angle of a
slope of the valley;
[0030] FIG. 3B is an enlarged view of a fracture starting point
groove of the large end portion for illustrating the width of an
opening of the valley;
[0031] FIG. 4 illustrates a method of fracturing and splitting the
large end portion;
[0032] FIG. 5A is a front view of a split type connecting rod
according to a second preferred embodiment of the present
invention;
[0033] FIG. 5B is a cross-sectional view of the split type
connecting rod shown in FIG. 5A along a line V-V;
[0034] FIG. 6 is a cross-sectional view of the split type
connecting rod shown in FIG. 5B along a line VI-VI;
[0035] FIG. 7 is a cross-sectional view of the split type
connecting rod shown in FIG. 5B along a line VII-VII;
[0036] FIG. 8 is a perspective view of an example of a cap-side
metal bearing portion with a protruding locking lug provided at
only one of the two ends; and
[0037] FIG. 9 is a perspective view of the split type connecting
rod provided with the cap-side metal bearing portion shown in FIG.
8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] With reference now to the attached drawings, embodiments of
the present invention will be explained below.
First Preferred Embodiment
[0039] FIGS. 1 to 4 illustrate a split type connecting rod
according to a first preferred embodiment of the present invention.
FIG. 1 is a front view of the split type connecting rod, FIG. 2 is
a cross-sectional view of a large end portion of the split type
connecting rod, FIG. 3A and FIG. 3B are enlarged views of a
fracture starting point groove of the large end portion and FIG. 4
illustrates a method of fracturing and splitting the large end
portion.
[0040] In these figures, reference numeral 100 denotes a split type
connecting rod of the present preferred embodiment, which is
preferably a nut-less type of connecting rod formed by forging,
casting or sintering, or other suitable process. This split type
connecting rod 100 is provided with a small end 101c having a
piston-pin hole 101b at one end of a rod body 101a and a large end
portion 101e having a crank-pin hole 101d at the other end.
[0041] The large end portion 101e is provided with shoulders 101f
which extend rightward and leftward from the connection with the
rod body 101a, and the crank-pin hole 101d is formed at the central
portion between both shoulders 101f. Furthermore, bolt holes 101g
which extend from the underside to the vicinity of the topside of
the large end portion 101e are formed in the shoulders 101f.
[0042] In the large end portion 101e, a rod portion 102 and a cap
portion 103 are preferably integral and define a single, unitary
structure that is formed beforehand and the entire split type
connecting rod 100 including the large end portion 101e is
subjected to surface hardening treatment such as carburization and
tempering. The large end portion 101e is fractured and split into a
rod portion 102 and cap portion 103 along a predetermined fracture
plane (straight line A in the figure). Fracturing and splitting
into the rod portion 102 and cap portion 103 is performed as shown
in FIG. 4 by placing the split type connecting rod 100 on a base
110, inserting sliders 111 which are movable in the diameter
direction into the crank-pinhole 101d of the large end portion 101e
and driving a wedge 112 between both sliders 111.
[0043] Then, these fractured and split rod portion 102 and cap
portion 103 are aligned with each other by contacting both
fractured and split surfaces with each other and coupled by
coupling bolts 104 fitted in the respective bolt holes 101g.
[0044] Through the surface hardening treatment, a surface hardened
layer having a predetermined carburization depth is formed on the
outer surface of the split type connecting rod 100. For the surface
hardening treatment, not only carburization and tempering but also
nitriding, thermal spraying, vapor deposition or high-frequency
quenching, or other suitable process, can be used.
[0045] On the inner circumferential surface of the crank-pin hole
101d, a pair of fracture starting point grooves 105 which extend in
the shaft center direction of the crank-pin hole 101d are
preferably formed. The fracture starting point grooves 105 are
preferably formed by notching through cutting, wire cutting (wire
cutting electric discharge machining) or machining using a laser,
or other suitable process, and are formed along a line of
intersection between the plane that will define a fracture plane
(expressed by straight line A in the figure) between the rod
portion 102 and cap portion 103 of the large end portion 101e, and
the inner circumferential surface. That is, in the case of forming
the fracture starting point grooves 105 by, e.g. wire cutting, a
conductive wire is placed near a predetermined position of the
inner circumferential surface of the crank-pin hole 101d and a
pulsed high voltage is applied between this conductive wire and the
inner circumferential surface of the crank-pin hole 101d. This
produces a corona discharge between the conductive wire and the
inner circumferential surface of the crank-pin hole 101d and this
discharge causes a portion of the inner circumferential surface of
the crank-pin hole 101d to be shaved, thereby forming the fracture
starting point grooves 105.
[0046] Between the inner circumferential surface of the crank-pin
hole 101d and the fracture starting point grooves 105, a valley 106
is formed. The valley 106 is formed by chamfering upper and lower
corners which are formed by the fracture starting point grooves 105
and the inner circumferential surface of the crank-pin hole 101d.
Furthermore, the opening of the valley 106 is preferably wider than
the opening of the fracture starting point grooves 105. This valley
106 is preferably formed through machining such as wire cutting as
with the fracture starting point grooves 105 or simultaneously with
molding of the split type connecting rod 100 through forging,
casting or sintering, or other suitable process.
[0047] As shown in FIG. 2, FIG. 3A and FIG. 3B, sloped portions
106a making up the valley 106 are preferably formed by linear
notching in such a way that an angle .beta. formed with the
straight line A (a plane that will define a fracture plane) passing
from the shaft center a of the crank-pin hole 101d through a bottom
portion 105a in a bottom surface 105c of the fracture starting
point grooves 105 is preferably about 45 degrees. This causes the
interior angle of the valley 106 to be approximately 90 degrees.
Furthermore, upper and lower inner surfaces 105b of the fracture
starting point groove 105 are formed in such a way that an angle
.alpha. formed with the straight line A is approximately 0 degrees,
that is, substantially parallel to the straight line A.
[0048] Furthermore, the valley 106 preferably has a greater opening
width L4 than an opening width L3 of the fracture starting point
groove 105. This causes the sloped portions 106a making up the
valley 106 to function as chamfers when a bi-partitioned metal
bearing (not shown) is inserted into the crank-pin hole 101d in the
direction of the bolt hole 101g.
[0049] Here, the chamfering function of the sloped portions 106a
will be explained. When no chamfering is applied to the corners,
the metal bearing contacts the corners when the metal bearing is
fitted into the crank-pin hole. Metal plating such as Sn (tin)
plating is applied to the surface of the metal bearing as an
anti-corrosion layer. When this plated layer comes into contact
with the sharp corners formed by fracturing and splitting, a
portion of the plated layer is shaved into particles and these
particles are stuck to the fracture surface. The stuck particles
hamper high-precision recoupling of the split type connecting rod.
In contrast, when chamfering is applied to the corners, that is,
when the valley 106 is formed, a portion of the plated layer is
hardly shaved, making it possible to suppress generation of
particles which is a factor in the hampering of high-precision
recoupling of the split type connecting rod.
[0050] The ratio of the depth L2 of the fracture starting point
groove 105 to a shortest distance L1 from the base point of the
fracture starting point groove 105 (that is, a boundary 107 between
the inner surface 105b and sloped portion 106a) to the edge of the
bolt hole 101g is preferably about 70% or above.
[0051] Thus, according to this preferred embodiment, a pair of
fracture starting point grooves 105 which extend in the inner
circumferential surface of the crank-pin hole 101d in the shaft
center direction are formed, sloped portions 106a are formed in the
upper and lower corners between the fracture starting point groove
105 and the inner circumferential surface of the crank-pin hole
101d. The valley 106 preferably has an opening width L4 that is
wider than the opening width L3 of the fracture starting point
groove 105. In other words, the angle .beta. formed by the valley
106 and the straight line A is preferably greater than the angle
.alpha. formed by the fracture starting point groove 105. As a
result, it is possible to set a greater ratio of the depth L2 of
the fracture starting point groove 105 to the shortest distance L1
from the base point of the fracture starting point groove 105 to
the edge of the bolt hole 101g with respect to the inner
circumferential surface of the crank-pin hole 101d as the base
point and reliably form a hardened layer through surface hardening
treatment up to the bottom portion 105a of the fracture starting
point groove 105. This makes it possible to increase a stress
expansion coefficient at the bottom portion 105a of the fracture
starting point groove 105, to prevent peeling or falling at the
time of fracturing and splitting, and to avoid problems such as
damage or burning due to falling when the engine is running.
Second Preferred Embodiment
[0052] FIG. 5A, FIG. 5B, FIG. 6 and FIG. 7 illustrate a split type
connecting rod according to a second preferred embodiment of the
present invention. FIG. 5A is a front view of the split type
connecting rod of this embodiment, FIG. 5B is a cross-sectional
view of the split type connecting rod shown in FIG. 5A along a line
V-V, FIG. 6 is a cross-sectional view of the split type connecting
rod shown in FIG. 5B along a line VI-VI and FIG. 7 is a
cross-sectional view of the split type connecting rod shown in FIG.
5B a long a line VII-VII. The split type connecting rod which will
be explained in this preferred embodiment preferably has a basic
configuration similar to that of the split type connecting rod 100
explained in the first preferred embodiment and identical
components or components corresponding to each other between the
two preferred embodiments are assigned the same reference numerals
and detailed explanations thereof will be omitted.
[0053] A split type connecting rod 200 in this preferred embodiment
is provided with a substantially ring-shaped metal bearing 213 on
the inner circumferential surface of a crank-pin hole 101d. This
metal bearing 213 is split into two portions of a rod-side metal
bearing portion 213a and a cap-side metal bearing portion 213b
along splitting lines on which the fracture plane (straight line A)
and the crank-pin hole 101d cross each other. That is, fracture
starting point grooves 105 and the rod-side metal bearing portion
213a and the cap-side metal bearing portion 213b each preferably
have a substantially semicircular shape.
[0054] Furthermore, bearing locking grooves 201h and 201i are
provided on the one splitting line side of the inner
circumferential surface of the crank-pin hole 101d, while bearing
locking grooves 201h' and 201i' are provided on the other splitting
line side. As shown in FIG. 6, the bearing locking grooves 201h,
201h', 201i, 201i' are preferably formed by revolving a grooving
cutter T which is placed in such a way as to be inscribed in the
crank-pin hole 101d and cutting to a predetermined depth. The
bearing locking grooves 201h, 201h', 201i, 201i' are preferably
arc-shaped when viewed in the shaft center direction of the
crank-pin hole 101d (see FIG. 6 and FIG. 7).
[0055] Furthermore, when viewed in the direction that is
substantially perpendicular to the shaft center of the crank-pin
hole 101d, the bearing locking grooves 201h, 201h' 201i, 201i' are
formed so as to extend over the splitting line in the
circumferential direction and so as to deviate to either side of
the splitting line in the circumferential direction (see FIG. 5B).
More specifically, the bearing locking grooves 201h, 201h' deviate
to the rod portion 102 side, while the bearing locking grooves
201i, 201i' deviate to the cap portion 103 side. In other words, of
the bearing locking grooves 201h, 201i juxtaposed to each other in
the shaft center direction of the crank-pin hole 101d, the bearing
locking groove 201h is formed so as to deviate to the rod portion
102 side, while the bearing locking groove 201i is formed so as to
deviate to the cap portion 103 side. On the other hand, of the
bearing locking grooves 201h', 201i' juxtaposed to each other in
the shaft center direction of the crank-pin hole 101d, the bearing
locking groove 201h' is formed so as to deviate to the rod portion
102 side, while the bearing locking groove 201i' is formed so as to
deviate to the cap portion 103 side.
[0056] Furthermore, as shown in FIG. 6, locking lugs 213c, 213c',
preferably two lugs each, are provided on the back of both ends
213a' of the substantially semi-circular rod-side metal bearing
portion 213a, and locking lugs 213d, 213d', preferably two lugs
each, are provided on the back of both ends 213b' of the
substantially semi-circular cap-side metal bearing portion 213b.
The locking lugs 213c are locked by the bearing locking grooves
201h, 201i formed on the split type connecting rod 200 side, while
the locking lugs 213c' are locked by the bearing locking grooves
201h', 201i' formed on the split type connecting rod 200 side. The
locking lugs 213d are locked by the bearing locking grooves 201h,
201i formed on the split type connecting rod 200 side, while the
locking lugs 213d' are locked by the bearing locking grooves 201h',
201i' formed on the split type connecting rod 200 side.
[0057] More specifically, since the bearing locking grooves 201h,
201h', 201i, 201i' are deviated to either side of the splitting
line in the circumferential direction, the locking lugs 213c, 213c'
of the rod-side metal bearing portion 213a are locked at the ends
on the rod portion 102 side of the bearing locking grooves 201i,
201i' deviated to the cap portion 103 side. The locking lugs 213d,
213d' of the cap-side metal bearing portion 213b are locked at the
ends on the cap portion 103 of the bearing locking grooves 201h,
201h' deviated to the rod portion 102 side.
[0058] The operations and effects of the preferred embodiment of
the present invention will be explained.
[0059] According to the bearing structure of this preferred
embodiment, the locking lugs 213c. 213c' of the rod-side metal
bearing portion 213a are locked at the end of the bearing locking
grooves 201i, 201i' and the locking lugs 213d, 213d' of the
cap-side metal bearing portion 213b are locked at the end of the
bearing locking grooves 201h, 201h', and therefore it is possible
to prevent the rod-side metal bearing portion 213a and cap-side
metal bearing portion 213b from moving in the circumferential
direction.
[0060] Here, since the bearing locking grooves 201h, 201h', 201i,
201i' are deviated in the circumferential direction, it is possible
to lock the locking lugs 213c, 213c', 213d, 213d' at the end of the
bearing locking grooves 201h, 201h', 201i, 201i' without reducing
the diameter of the grooving cutter T, that is, the diameters of
the bearing locking grooves 201h, 201h', 201i, 201i'. It is also
possible to avoid the problem of stress concentration caused by
reducing the diameters of the bearing locking grooves 201h, 201h',
201i, 201i'. That is, when the necessary depth is secured while
reducing the diameter of the grooving cutter T, i.e. the diameters
of the bearing locking grooves 201h, 201h', 201i, 201i', the shape
changes drastically in the bearing locking groove on the internal
surface of the crank-pin hole 101d and the problem of stress
concentration is likely to occur. On the other hand, when the
diameters of the bearing locking grooves 201h, 201h', 201i, 201i'
are simply increased, the locking lugs 213c, 213c', 213d, 213d'
move easily in the circumferential direction in the bearing locking
grooves 201h, 201h', 201i, 201i', which makes it easier for the
metal bearing 213 to move in the circumferential direction.
However, this preferred embodiment can prevent this problem because
the locking lugs 213c, 213c', 213d, 213d' are locked at the end of
the bearing locking grooves 201h, 201h', 201i, 201i'.
[0061] In this preferred embodiment, the bearing locking grooves
are preferably formed on both splitting lines, but the bearing
locking grooves of various preferred embodiments of the present
invention may be formed only on one splitting line. That is, as
shown in FIG. 6 and FIG. 7, this preferred embodiment assumes that
the locking lugs 213c, 213c' protrude from both ends 213a' of the
rod-side metal bearing portion 213a and the locking lugs 213d,
213d' protrude from both ends 213b' of the cap-side metal bearing
portion 213b. However, it is also possible to use the rod-side
metal bearing portion 213a from which a locking lug (e.g., locking
lug 213c) protrudes for only one of both ends 213a' and use the
cap-side metal bearing portion 213b from which a locking lug
(locking lug 213d when only the locking lug 213c protrudes from the
rod-side metal bearing portion 213a) protrudes for only one of both
ends 213b'. FIG. 8 is a perspective view of one example of the
cap-side metal bearing portion 213b from which one locking lug 213d
protrudes for only one of both ends 213b'. Furthermore, FIG. 9 is a
perspective view of the split type connecting rod 200 when this
cap-side metal bearing portion 213b is attached. As shown in FIG.
9, the locking lug 213d of the cap-side metal 213b is locked by the
bearing locking groove 201h provided on the inner circumferential
surface of the crank-pin hole 101d. In actual use of such a
cap-side metal bearing portion 213b, the rod-side metal bearing
portion 213a where one locking lug 213c is provided on one of the
two ends 213a' so as to be locked by the bearing locking groove
201i is also attached together. Therefore, it is possible to stop
rotation in the circumferential direction of the rod-side metal
bearing portion 213a and cap-side metal bearing portion 213b. Thus,
it is possible to realize the operations and effects similar to
those of the split type connecting rod 200 explained in this
preferred embodiment without providing the bearing locking grooves
201h', 201i'.
[0062] In the above-described case, it is also possible to
introduce the features of the split type connecting rod 100
explained in the first preferred embodiment into the split type
connecting rod 200 of this preferred embodiment. More specifically,
it is possible to form the valley 106 explained in the first
preferred embodiment at positions where the bearing locking grooves
201h', 201i' are not provided, that is, at the positions on the
predetermined fracture plane facing the bearing locking grooves
201h, 201i on the inner circumferential surface of the crank-pin
hole 101d.
[0063] The present invention is not limited to the above described
preferred embodiments, and various variations and modifications may
be possible without departing from the scope of the present
invention.
[0064] This application is based on the Japanese Patent Application
No. 2002-378020 filed on Dec. 26, 2002 and the Japanese Patent
Application No. 2003-315615 filed on Sep. 8, 2003, the entire
contents of which are expressly incorporated by reference
herein.
[0065] While preferred embodiments of the present invention have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing the scope and spirit of the present invention. The scope
of the present invention, therefore, is to be determined solely by
the following claims.
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