U.S. patent application number 13/579342 was filed with the patent office on 2012-12-06 for bearing oil feed device.
Invention is credited to Kenji Watanabe.
Application Number | 20120304957 13/579342 |
Document ID | / |
Family ID | 44506377 |
Filed Date | 2012-12-06 |
United States Patent
Application |
20120304957 |
Kind Code |
A1 |
Watanabe; Kenji |
December 6, 2012 |
BEARING OIL FEED DEVICE
Abstract
A partial groove 14 is formed in an inner circumferential
surface of an upper side bearing member 11 of a main bearing 5
which pivotally supports a main shaft 3A of a crankshaft 3, and a
space D between an end portion of the partial groove 14 and each of
crush reliefs 11b formed at both ends in a circumferential
direction of the upper side bearing member 11 is provided within a
range of 2 mm.ltoreq.D.ltoreq.main shaft diameter/3. Further, a
depth gradually decreasing portion 14b having an arc-shaped section
is formed at an end portion of the partial groove 14, and a radius
r of the depth gradually decreasing portion 14b is provided within
a range of 0.ltoreq.r.ltoreq.main bearing inner circumferential
surface radius.times.0.5. Further, in a connecting rod bearing 6, a
lubricating oil discharge passage 23, which discharges a
lubricating oil outside a connecting rod 4 when communicating with
an internal passage 3C formed in the crankshaft 3, is provided. An
amount of the lubricating oil which is discharged from a sliding
portion of the main bearing is suppressed, and damage to the main
bearing and the connecting rod bearing due to a foreign substance
in the lubricating oil can be prevented as much as possible.
Inventors: |
Watanabe; Kenji;
(Toyota-shi, JP) |
Family ID: |
44506377 |
Appl. No.: |
13/579342 |
Filed: |
November 5, 2010 |
PCT Filed: |
November 5, 2010 |
PCT NO: |
PCT/JP2010/069669 |
371 Date: |
August 16, 2012 |
Current U.S.
Class: |
123/196R |
Current CPC
Class: |
F16C 17/022 20130101;
F16C 33/106 20130101; F16C 33/1055 20130101; F16C 9/00 20130101;
F16C 17/246 20130101; F16C 33/046 20130101; F16C 3/14 20130101 |
Class at
Publication: |
123/196.R |
International
Class: |
F01M 1/06 20060101
F01M001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 26, 2010 |
JP |
2010-043450 |
Claims
1. A bearing oil feed device, comprising a crankshaft including a
plurality of main shafts and crankpins, a plurality of main
bearings which are each configured by a semi-cylindrical upper side
bearing member and lower side bearing member, and each pivotally
supports the main shaft rotatably at a cylinder block, and a
plurality of connecting rod bearings which each pivotally supports
the crankpin rotatably at a connecting rod, in which a radial hole
which communicates with a lubricating oil passage formed inside the
cylinder block is formed in the upper side bearing member in the
main bearing, and a lubricating oil which is supplied to a sliding
portion of the main bearing and the main shaft via the radial hole
is supplied to a sliding portion of the crankpin and the connecting
rod bearing via an internal passage which is formed inside the
crankshaft and is opened to the main shaft and the crankpin,
wherein a partial groove which is formed in a circumferential
direction of an inner circumferential surface of the upper side
bearing member in the main bearing, to which the radial hole is
opened, and which communicates with an opening of the internal
passage of the main shaft is formed, a space D between an end
portion of the partial groove and each of crush reliefs formed at
both ends in a circumferential direction of the upper side bearing
member is provided within a range of 2mm.ltoreq.D.ltoreq.main shaft
diameter/3 (1), a depth gradually decreasing portion which is
formed to be arc-shaped in section seen from an axial direction of
the upper side bearing member is formed at the end portion of the
partial groove, and a radius r of the depth gradually decreasing
portion is provided within a range of 0.ltoreq.r.ltoreq.main
bearing inner circumferential surface radius.times.0.5 (2), and a
lubricating oil discharge passage which communicates with the
internal passage formed in the crankshaft to discharge the
lubricating oil is provided in the connecting rod bearing.
2. A bearing oil feed device, comprising a crankshaft including a
plurality of main shafts and crankpins, a plurality of main
bearings which each pivotally supports the main shaft rotatably at
a cylinder block, and are each configured by a semi-cylindrical
upper side bearing member and lower side bearing member, and a
plurality of connecting rod bearings which each pivotally supports
the crankpin rotatably at a connecting rod, in which a radial hole
which communicates with a lubricating oil passage formed inside the
cylinder block is formed in the upper side bearing member in the
main bearing, and a lubricating oil which is supplied to a sliding
portion of the main bearing and the main shaft via the radial hole
is supplied to a sliding portion of the crankpin and the connecting
rod bearing via an internal passage which is formed inside the
crankshaft and is opened to the main shaft and the crankpin,
wherein a partial groove which is formed in a circumferential
direction of an inner circumferential surface of the upper side
bearing member in the main bearing, to which the radial hole is
opened, and which communicates with an opening of the internal
passage of the main shaft is formed, a space D between an end
portion of the partial groove and each of crush reliefs formed at
both ends in a circumferential direction of the upper side bearing
member is provided within a range of 2mm.ltoreq.D.ltoreq.main shaft
diameter/3 (1), a depth gradually decreasing portion with a depth
gradually decreasing is formed at the end portion of the partial
groove, and an angle .theta. formed by the depth gradually
decreasing portion and the inner circumferential surface of the
upper side bearing member is provided within a range of
0.gtoreq.25.degree. (3), and a lubricating oil discharge passage
which communicates with the internal passage formed in the
crankshaft to discharge the lubricating oil is provided in the
connecting rod bearing.
3. The bearing oil feed device according to claim 2, wherein the
angle .theta. formed by the depth gradually decreasing portion and
the inner circumferential surface of the upper side bearing member
is provided within a range of
30.degree..ltoreq..theta..ltoreq.45.degree..
4. The bearing oil feed device according to claim 1, wherein the
oil discharge passage in the connecting rod bearing is configured
by a through-hole which penetrates to an outer circumferential
surface from an inner circumferential surface of the connecting rod
bearing, and a foreign substance discharge groove which is formed
in the outer circumferential surface of the connecting rod bearing
to communicate with the through-hole and communicate with at least
one end surface of the connecting rod bearing.
5. The bearing oil feed device according to claim 1, wherein the
oil discharge passage in the connecting rod bearing includes a
foreign substance discharge groove which is formed in the inner
circumferential surface of the connecting rod bearing and
communicates with at least one end surface of the connecting rod
bearing.
Description
TECHNICAL FIELD
[0001] The present invention relates to a bearing oil feed device,
and more particularly to a bearing oil feed device which is
favorable in a case of feeding oil to a crankshaft of an engine for
an automobile, for example.
BACKGROUND ART
[0002] Conventionally, an engine for an automobile, for example,
includes a crankshaft including a plurality of main shafts and
crank pins, a plurality of main bearings each configured by a
semi-cylindrical upper side bearing member and lower side bearing
member which pivotally and rotatably and supports the above
described main shaft at a cylinder block, and a plurality of
connecting rod bearings which pivotally and rotatably support the
above described crankpins at connecting rods.
[0003] There are known bearing oil feed devices in each of which in
order to lubricate the main shafts and the crankpins, a radial hole
which communicates with a lubricating oil passage which is formed
inside a cylinder block is formed in the upper side bearing member
of the above described main bearing, a lubricating oil is supplied
to a sliding portion of each of the main bearings and the main
shaft, and the lubricating oil which is supplied to the sliding
portion is supplied to a sliding portion of the above described
crankpin and the connecting rod bearing via an internal passage
formed in an inside of the crankshaft (Patent Literature 1, Patent
Literature 2 and Patent Literature 3).
[0004] Further, as the bearing oil feed device as above, there is
known the bearing oil feed device in which an oil groove is formed
in an entire periphery of the upper side bearing member of the main
bearing, the oil groove is opened to a joint portion of a
half-split bearing and a space is formed in the joint portion,
whereby a foreign substance in the oil groove is discharged from
the main bearing with the lubricating oil to make it difficult for
the above described foreign substance from entering the connecting
rod bearing via the internal passage formed in the crankshaft (FIG.
2 of Patent Literature 4).
PRIOR ART DOCUMENTS
Patent Literature
[0005] Patent Literature 1: Japanese Patent Laid-Open No.
4-219521
[0006] Patent Literature 2: Japanese Patent Laid-Open No.
5-215125
[0007] Patent Literature 3: Japanese Patent Laid-Open No.
7-27127
[0008] Patent Literature 4: Japanese Patent Laid-Open No.
2005-076755
SUMMARY OF INVENTION
Problems to be Solved by the Invention
[0009] However, in recent years, low friction of a crankshaft has
been required, and it is found out that the amount of the
lubricating oil which is discharged from the sliding portion of a
main shaft and a main bearing gives a larger influence on the
friction than the amount of the lubricating oil which is discharged
from the sliding portion of a crankpin and a connecting rod
bearing.
[0010] In contrast with this, in the bearing oil feed device of
Patent Literature 4, a groove is formed in the entire periphery of
the upper side bearing member, and a space is formed in the joint
portion, whereby a problem arises that the amount of the
lubricating oil which is discharged from the sliding portion of the
main shaft and the main bearing is large.
[0011] In the light of the problem like this, the present invention
provides a bearing oil feed device which suppresses an amount of a
lubricating oil which is discharged from a sliding portion of a
main bearing, and can prevent damage to the main bearing and a
connecting rod bearing due to a foreign substance which flow in the
above described lubricating oil as much as possible.
Means for Solving the Problems
[0012] More specifically, a bearing oil feed device according to
claim 1 is a bearing oil feed device including a crankshaft
including a plurality of main shafts and crankpins, a plurality of
main bearings which are each configured by a semi-cylindrical upper
side bearing member and lower side bearing member, and each
pivotally supports the main shaft rotatably at a cylinder block,
and a plurality of connecting rod bearings which each pivotally
supports the crankpin rotatably at a connecting rod,
[0013] in which a radial hole which communicates with a lubricating
oil passage formed inside the cylinder block is formed in the upper
side bearing member in the main bearing, and a lubricating oil
which is supplied to a sliding portion of the main bearing and the
main shaft via the radial hole is supplied to a sliding portion of
the crankpin and the connecting rod bearing via an internal passage
which is formed inside the crankshaft and is opened to the main
shaft and the crankpin,
[0014] wherein a partial groove which is formed in a
circumferential direction of an inner circumferential surface of
the upper side bearing member in the main bearing, to which the
radial hole is opened, and which communicates with an opening of
the internal passage of the main shaft is formed,
[0015] a space D between an end portion of the partial groove and
each of crush reliefs formed at both ends in a circumferential
direction of the upper side bearing member is provided within a
range of
2mm.ltoreq.D.ltoreq.main shaft diameter/3 (1),
[0016] a depth gradually decreasing portion which is formed to be
arc-shaped in section seen from an axial direction of the upper
side bearing member is formed at the end portion of the partial
groove, and a radius r of the depth gradually decreasing portion is
provided within a range of
0.ltoreq.r.ltoreq.main bearing inner circumferential surface
radius.times.0.5 (2),
and
[0017] a lubricating oil discharge passage which communicates with
the internal passage formed in the crankshaft to discharge the
lubricating oil is provided in the connecting rod bearing.
[0018] Further, a bearing oil feed device according to claim 2 is a
bearing oil feed device including a crankshaft including a
plurality of main shafts and crankpins, a plurality of main
bearings which each pivotally supports the main shaft rotatably at
a cylinder block, and are each configured by a semi-cylindrical
upper side bearing member and lower side bearing member, and a
plurality of connecting rod bearings which each pivotally supports
the crankpin rotatably at a connecting rod,
[0019] in which a radial hole which communicates with a lubricating
oil passage formed inside the cylinder block is formed in the upper
side bearing member in the main bearing, and a lubricating oil
which is supplied to a sliding portion of the main bearing and the
main shaft via the radial hole is supplied to a sliding portion of
the crankpin and the connecting rod bearing via an internal passage
which is formed inside the crankshaft and is opened to the main
shaft and the crankpin,
[0020] wherein a partial groove which is formed in a
circumferential direction of an inner circumferential surface of
the upper side bearing member in the main bearing, to which the
radial hole is opened, and which communicates with an opening of
the internal passage of the main shaft is formed,
[0021] a space D between an end portion of the partial groove and
each of crush reliefs formed at both ends in a circumferential
direction of the upper side bearing member is provided within a
range of
2mm.ltoreq.D.ltoreq.main shaft diameter/3 (1),
[0022] a depth gradually decreasing portion with a depth gradually
decreasing is formed at the end portion of the partial groove, and
an angle .theta. formed by the depth gradually decreasing portion
and the inner circumferential surface of the upper side bearing
member is provided within a range of
.theta..gtoreq.25.degree. (3),
and
[0023] a lubricating oil discharge passage which communicates with
the internal passage formed in the crankshaft to discharge the
lubricating oil is provided in the connecting rod bearing.
Advantageous Effects of Invention
[0024] According to the inventions of the above described claim 1
and claim 2, the depth gradually decreasing portion of the inner
groove formed in the upper side bearing member of the above
described main bearing is formed in conformity with the above
described conditions, whereby the lubricating oil is stopped by the
above described depth gradually decreasing portion, and the
discharge amount of the lubricating oil from the sliding portion of
the main shaft and the main bearing can be suppressed.
[0025] Furthermore, the foreign substance in the lubricating oil
can be also kept to stay in the above described depth gradually
decreasing portion, and when the internal passage formed in the
crankshaft communicates with the depth gradually decreasing
portion, the foreign substance can be caused to flow into the
internal passage together with the above described lubricating
oil.
[0026] The foreign substance is discharged from the lubricating oil
discharge passage formed in the above described connecting rod
bearing, and therefore, damage to the above described main bearing
and the connecting rod bearing due to the foreign substance is
prevented.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a sectional view of a main part showing a first
embodiment of the present invention.
[0028] FIG. 2 is a partial enlarged view of a main bearing.
[0029] FIG. 3 is a partial enlarged view of a connecting rod
bearing.
[0030] FIG. 4 is a graph showing an experimental result.
[0031] FIG. 5 is a graph showing an experimental result.
[0032] FIG. 6 is a partial enlarged view of a main bearing in a
second embodiment.
[0033] FIG. 7 is a partial enlarged view of a connecting rod
bearing in the second embodiment.
[0034] FIG. 8 is a graph showing an experimental result.
MODE FOR CARRYING OUT THE INVENTION
[0035] Describing the present invention with respect to illustrated
embodiments hereinafter, FIG. 1 shows a sectional view of a main
part of an engine 1 for an automobile as a bearing oil feed device,
and the engine 1 includes a cylinder block 2, a crankshaft 3
pivotally supported rotatably at the cylinder block 2, and a
connecting rod 4 pivotally supported rotatably at the crankshaft
3.
[0036] The above described crankshaft 3 is configured by a main
shaft 3A pivotally supported at the cylinder block 2 via a main
bearing 5, a crankpin 3B pivotally supported at the connecting rod
4 via a connecting rod bearing 6, and a connecting member not
illustrated which connects the main shaft 3A and the crankpin
3B.
[0037] An internal passage 3C which allows the lubricating oil to
flow therethrough is formed inside the crankshaft 3, and the
internal passage 3C opens at a position opposed to a diameter
direction of an outer circumferential surface in the main shaft 3A,
and is formed in an oblique direction from one opening in the main
shaft 3A to open to an outer circumferential surface of the
crankpin 3B.
[0038] The above described main bearing 5 is configured to be
cylindrical by butting a semi-cylindrical upper side bearing member
11 and a semi-cylindrical lower side bearing member 12 which are a
pair of upper and lower members, and the main bearing 5 is fixed to
the above described cylinder block 2 by a cap 13 an inner surface
of which is formed into a semicircular shape.
[0039] The main shaft 3A of the above described crankshaft 3 slides
in contact with inner circumferential surfaces of the upper side
bearing member 11 and the lower side bearing member 12, and the
inner circumferential surface of the main bearing 5 and the outer
circumferential surface of the main shaft 3A configure a sliding
portion.
[0040] A lubricating oil passage 2A is formed inside the above
described cylinder block 2, a radial hole 11a is formed in the
upper side bearing member 11 of the main bearing 5 to correspond to
a position of a lower end portion of the lubricating oil passage
2A.
[0041] By the radial hole 11a, the lubricating oil which flows via
the above described lubricating oil passage 2A is supplied to the
sliding portion of the main bearing 5 and the main shaft 3A via the
radial hole 11a, and lubricates the sliding portion.
[0042] The main bearing 5 of the present embodiment is provided
with a partial groove 14 which is formed in a circumferential
direction in the inner circumferential surface of the above
described upper side bearing member 11, and the partial groove 14
communicates with the opening of the internal passage 3C of the
main shaft 3A which rotates.
[0043] Meanwhile, in the above described lower side bearing member
12, the above described radial hole 11a and the partial groove 14
are not formed, and a load which is exerted from the crankshaft 3
is received by the entire inner circumferential surface of the
lower side bearing member 12.
[0044] Describing the above described partial groove 14 in more
detail, FIG. 2 shows an enlarged view of a border portion of the
upper side bearing member 11 and the lower side bearing member 12
in the above described main bearing 5, and in a joint portion of
both the bearing members 11 and 12, crush reliefs 11b and 12a and
chamfers 11c and 12b are formed respectively.
[0045] The above described partial groove 14 is configured by a
groove portion 14a which is formed with a predetermined depth, and
a depth gradually decreasing portion 14b which is adjacent to the
groove portion 14a and has the depth gradually decreasing up to a
position the inner circumferential surface, and the above described
radial hole 11a opens to the above described groove portion
14a.
[0046] An end portion of the above described partial groove 14,
that is, a position at which a depth of the depth gradually
decreasing portion 14b becomes zero is set within the following
range when a distance between the end portion of the partial groove
14 and the above described crush relief 11b is set as D.
2mm.ltoreq.D.ltoreq.main shaft diameter/3 (1)
[0047] Further, the above described depth gradually decreasing
portion 14b is machined to be in a circular arc shape of a radius r
when seen from the axial direction of the main bearing 5, and the
radius r of the depth gradually decreasing portion 14b is set
within the following range.
0.ltoreq.r.ltoreq.main bearing inner circumferential surface
radius.times.0.5 (2)
[0048] Next, the connecting rod bearing 6 is configured to be
cylindrical by butting a pair of upper and lower half-split
bearings 21 and 22, and is held by semicircular recessed portions
formed in a connecting rod main body 4a and a connecting rod cap
4b.
[0049] The crankpin 3B of the above described crankshaft 3 is in
sliding contact with inner circumferential surfaces of the two
half-split bearings 21 and 22, and the inner circumferential
surface of the connecting rod bearing 6 and the outer
circumferential surface of the crankpin 3B configure a sliding
portion.
[0050] FIG. 3 shows a partial enlarged view of the connecting rod
bearing 6, in a joint portion of the half-split bearings 21 and 22,
crush reliefs 21a and 22a and chamfers 21b and 22b are formed
respectively, and the joint portion is provided with a lubricating
oil discharge passage 23 which communicates with the internal
passage 3c formed in the crankshaft 3 to discharge the lubricating
oil.
[0051] The above described lubricating oil discharge passage 23 is
configured by a through-hole 23a which is formed in a position of
the above described joint portion and penetrates in a radial
direction, and a foreign substance discharge groove 23b which is
formed in outer circumferential surfaces of the half-split bearings
21 and 22 and communicates with the above described through-hole
23a.
[0052] The above described through-hole 23a is provided by being
bored in a central portion in the axial direction in the connecting
rod bearing 6, and is formed in a position superimposed on a
movement trajectory of the opening of the internal passage 3C by
rotation of the crankpin 3B.
[0053] Further, an inside diameter of the through-hole 23a is set
to be a dimension which allows the maximum foreign substance
assumed to be included in the lubricating oil to pass, and is set
to be larger than an inside diameter of the internal passage 3C
which opens to the above described crankpin 3B.
[0054] The above described foreign substance discharge groove 23b
is configured by two notches formed respectively at edge portions
of the outer circumferential surfaces of the above described two
half-split bearings 21 and 22, and are respectively formed to
penetrate in the axial direction of the connecting rod bearing
6.
[0055] Further, a width of the foreign substance discharge groove
23b is set to be a dimension smaller than the inside diameter of
the above described through-hole 23a, and a depth of the foreign
substance discharge groove 23b is set at such a dimension as to
allow a foreign substance of the maximum size which is assumed in
advance to pass.
[0056] According to the configuration as above, a space is formed
between the above described foreign substance discharge groove 23b
and the inner circumferential surface of the connecting rod 4, and
the lubricating oil which passes through the above described
through-hole 23a is discharged from end surfaces at both sides of
the connecting rod 4 via the space.
[0057] An operation of the engine 1 having the above described
configuration will be described, and in particular, the moving path
of the lubricating oil which passes through the inside of the
engine 1 will be described.
[0058] When the engine 1 is operated, the lubricating oil passes
through the lubricating oil passage 2A of the cylinder block 2, and
thereafter, is supplied into the partial groove 14 of the main
bearing 5 via the radial hole 11a formed in the upper side bearing
member 11 of the main bearing 5.
[0059] Of the lubricating oil, a part of the lubricating oil
lubricates the sliding portion of the main bearing 5 and the main
shaft 3A from the partial groove 14, whereas the other lubricant
oil moves along the circumferential direction of the upper side
bearing member 11 inside the above described partial groove 14 with
rotation of the main shaft 3A, and thereafter, moves to the depth
gradually decreasing portion 14b of the partial groove 14.
[0060] Here, the above described depth gradually decreasing portion
14b is formed to be abruptly shallow based on the above described
(expression 2), and therefore, the lubricating oil in the partial
groove 14 is stopped by the depth gradually decreasing portion
14b.
[0061] Further, the depth gradually decreasing portion 14b is
formed in a position separated from the crush relief lib based on
the above described (expression 1), and therefore, the blocked
lubricating oil is prevented from moving to the crush relief 11b
via a gap between the inner circumferential surface of the upper
side bearing member 11 and the outer circumferential surface of the
main shaft 3A.
[0062] When the opening of the internal passage 3C formed in the
above described main shaft 3A approaches the depth gradually
decreasing portion 14b of the partial groove 14 in this state, the
lubricating oil which is stopped by the depth gradually decreasing
portion 14b flows into the internal passage 3C at once, and most of
the lubricating oil supplied to the main bearing 5 flows into the
internal passage 3C.
[0063] As above, the lubricating oil is stopped by the above
described depth gradually decreasing portion 14b, whereby the
amount of the lubricating oil which is discharged outside from the
sliding portion of the main shaft 3A and the main bearing 5 can be
suppressed, and the sliding portion of the main shaft 3A and the
main bearing 5 is lubricated by a suitable amount of the
lubricating oil.
[0064] Meanwhile, when a foreign substance is contained inside the
lubricating oil which is supplied from the above described cylinder
block 2, the foreign substance flows into the partial groove 14
which is formed in the upper side bearing member 11 via the above
described lubricating oil passage 2A and the radial hole 11a with
the lubricating oil.
[0065] The foreign substance in the partial groove 14 moves to the
depth gradually decreasing portion 14b of the partial groove 14
with the lubricating oil, but the foreign substance is inhibited
from moving outside the partial groove 14 by the depth gradually
decreasing portion 14b similarly to the lubricating oil.
[0066] Thereafter, the foreign substance staying in the depth
gradually decreasing portion 14b flows into the internal passage 3C
simultaneously with the above described lubricating oil flowing
into the internal passage 3C at once when the internal passage 3C
which opens to the above described main shaft 3A passes the depth
gradually decreasing portion 14b.
[0067] As above, the foreign substance in the lubricating oil which
flows in the above described partial groove 14 flows into the
internal passage 3C of the crankshaft 3 without entering between
the main shaft 3A and the main bearing 5, owing to the depth
gradually decreasing portion 14b, and therefore, damage of the
sliding portion of the main shaft 3A and the main bearing 5 due to
foreign substance is prevented.
[0068] Subsequently, the lubricating oil which flows into the
internal passage 3C moves to the crankpin 3B side with the rotation
of the crankshaft 3, and thereafter, is discharged to the sliding
portion with the connecting rod bearing 6 from the opening which is
formed in the outer periphery of the crankpin 3B.
[0069] Of the lubricating oil, a part of the lubricating oil
lubricates the sliding portion of the crankpin 3B and the
connecting rod bearing 6, and the other lubricating oil is
discharged outside the connecting rod 4 from the lubricating oil
discharge passage 23 formed in the above described connecting rod
bearing 6.
[0070] Describing more specifically, when the opening of the
internal passage 3C formed in the above described crankpin 3B
reaches the joint portion of the two half-split bearings 21 and 22,
the opening of the internal passage 3C communicates with the
through-hole 23a of the above described lubricating oil discharge
passage 23, and the lubricating oil in the internal passage 3C
flows into the above described foreign substance discharge groove
23b via the through-hole 23a.
[0071] The foreign substance discharge groove 23b is formed in the
axial direction of the connecting rod bearing 6, and therefore, the
lubricating oil is discharged outside the connecting rod 4 from the
end surfaces at both sides of the connecting rod bearing 6 via the
foreign substance discharge groove 23b.
[0072] At this time, the foreign substance contained in the
lubricating oil in the above described internal passage 3C is also
discharged outside the connecting rod 4 from the lubricating oil
discharge passage 23, whereby damage to the crankpin 3B and the
connecting rod bearing 6 due to the foreign substance is prevented,
and the through-hole 23a and the foreign substance discharge groove
23b are formed to be larger than the foreign substance, whereby the
foreign substance does not close the lubricating oil discharge
passage 23.
[0073] As above, according to the engine 1 of the present
embodiment, the partial groove 14 is formed in the upper side
bearing member 11 of the main shaft 3A, and the depth gradually
decreasing portion 14b of the partial groove 14 is formed under the
conditions of the above described (expression 1) and (expression
2), whereby most of the lubricating oil which is supplied to the
sliding portion of the main shaft 3A and the main bearing 5 can be
caused to flow into the internal passage 3C which is formed in the
crankshaft 3.
[0074] As a result, the amount of the lubricating oil which is
discharged from the sliding portion of the main shaft 3A and the
main bearing 5 can be suppressed, and the foreign substance
contained in the lubricating oil can be discharged to the internal
passage 3C, whereby damage to the main shaft 3A and the main
bearing 5 can be prevented.
[0075] Furthermore, the foreign substance contained in the
lubricating oil which is supplied to the above described internal
passage 3C is discharged outside the connecting rod 4 together with
the lubricating oil by the lubricating oil discharge passage 23
which is formed in the above described connecting rod bearing 6,
and therefore, damage to the crankpin 3B and the connecting rod
bearing 6 by the foreign substance can be also prevented.
[0076] FIG. 4 and FIG. 5 show graphs showing experimental results
of the engine 1 according to the above described embodiment.
[0077] In the experiment, the above described engine 1 was operated
in a state in which the internal passage 3C of the crankshaft 3
having the above described configuration was closed, and a
predetermined amount of foreign substance was mixed into the
lubricating oil which was supplied from the lubricating oil passage
2A of the above described cylinder block 2, and how much foreign
substance remained in the partial groove 14 formed in the upper
side bearing member 11 in the above described main shaft 3A was
measured.
[0078] FIG. 4 is the experimental result about expression 1, and an
axis of abscissa represents a distance D between the end portion of
the partial groove 14 and the crush relief 11b, whereas an axis of
ordinates represents a ratio of the foreign substance mixed via the
lubricating oil passage 2A being recovered by the above described
partial groove 14. In the experiment of FIG. 4, an radius r of the
depth gradually decreasing portion 14b in expression 2 is set as a
radius of the inner circumferential surface of the main shaft
3A.times.0.5.
[0079] As is understood from FIG. 4, it can be understood that when
the distance D is set as 2 mm or more, the foreign substance
favorably remains in the partial groove 14, and it is predictable
that if the internal passage 3C of the above described crankshaft 3
communicates therewith in this state, the foreign substance is
favorably recovered into the internal passage 3C.
[0080] FIG. 5 is an experimental result about expression 2, and the
axis of abscissa represents a radius r of the depth gradually
decreasing portion 14b, whereas the axis of ordinates represents a
ratio of the foreign substance mixed via the lubricating oil
passage 2A being recovered by the above described partial groove
14. In the experiment of FIG. 5, the distance D between the end
portion of the partial groove 14 and the crush relief 11b in
expression 1 is set at 2 mm.
[0081] As is understood from FIG. 5, it can be understood that when
the radius r, the distance D is made smaller than the radius of the
inner circumferential surface of the main shaft 3A.times.0.5, the
foreign substance favorably remains in the partial groove 14, and
it is predictable that if the internal passage 3C of the above
described crankshaft 3 communicates therewith in this state, the
foreign substance is favorably recovered in the internal passage
3C.
[0082] FIG. 6 and FIG. 7 show partial sections of the engine 1 of a
second embodiment according to the present invention, FIG. 6 shows
an partial enlarged view of the main bearing 5 similarly to FIG. 2
of the above described first embodiment, and FIG. 7 shows a partial
enlarged view of the connecting rod bearing 6 similarly to FIG. 3
of the above described first embodiment.
[0083] The configuration of the parts other than the part which
will be described as follows is the same as the first embodiment,
and therefore, the detailed description thereof will be
omitted.
[0084] As shown in FIG. 6, the partial groove 14 is formed in the
upper side bearing member 11 of the main shaft 3A in the second
embodiment, and to the distance D between the end portion of the
partial groove 14 and the crush relief 11b, the relation of
(expression 1) in the above described first embodiment is
applied.
[0085] In the present embodiment, in the depth gradually decreasing
portion 14b which is formed at the end portion of the above
described partial groove 14, an angle .theta. which is formed by
the depth gradually decreasing portion 14b and the inner
circumferential surface of the upper side bearing member 11 is set
within the following range.
.theta..gtoreq.25.degree. (3)
[0086] Next, as shown in FIG. 7, a lubricating oil discharge
passage 123 is formed in the inner circumferential surface of the
connecting rod bearing 6, is more specifically configured by crush
reliefs 21a and 22a which are formed in a connection portion of the
above described half-split bearings 21 and 22, and chamfers 21b and
22b which are formed adjacently to the crush reliefs 21a and 22a,
and a foreign substance discharge groove 123a is formed by the
crush reliefs 21a and 22a and the chamfers 21b and 22b.
[0087] A depth from the outer circumferential surface of the above
described crankpin 3B to bottom portions of the chamfers 21b and
22b in the above described foreign substance discharge groove 123a
is set at a dimension which enables a maximum foreign substance
assumed to be mixed in the lubricating oil to pass.
[0088] By adopting the configuration as above, a space by the above
described foreign matter discharge groove 123a is formed between
the outer circumferential surface of the above described crankpin
3B and the inner circumferential surface of the connecting rod
bearing 6, and the space is penetrated in the axial direction of
the connecting rod bearing 6 to communicate with an outside of the
connecting rod 4.
[0089] In the engine 1 according to the above described second
embodiment, when the engine 1 is operated, the lubricating oil
flows through the lubricating oil passage 2A of the cylinder block
2, after which, the lubricating oil is discharged to the sliding
portion of the main bearing 5 and the main shaft 3A via the radial
hole 11a formed in the upper side bearing member 11 of the main
bearing 5, and the lubricating oil is supplied into the partial
groove 14 which is formed in the upper side bearing member 11.
[0090] Thereafter, when the lubricating oil in the partial groove
14 approaches the depth gradually decreasing portion 14b of the
partial groove 14, the lubricating oil in the partial groove 14 is
stopped by the depth gradually decreasing portion 14b because the
depth gradually decreasing portion 14b is formed in such a manner
that the depth of the partial groove 14 abruptly becomes small
based on the above described (expression 3).
[0091] Further, the depth gradually decreasing portion 14b is
formed at the position separated from the crush relief 11b based on
the above described (expression 1), and therefore, the lubricating
oil which is stopped does not move to the crush relief 11b via a
gap between the inner circumferential surface of the upper side
bearing member 11 and the main shaft 3A.
[0092] Next, when the lubricating oil which is stopped in the above
described depth gradually decreasing portion 14b flows into the
internal passage 3C, the lubricating oil is thereafter supplied to
the sliding portion of the crankpin 3B and the connecting rod
bearing 6 via the internal passage 3C, and most of the lubricating
oil is discharged to outside the connecting rod 4 when the opening
at the above described crankpin 3B side in the internal passage 3C
communicates with the lubricating oil discharge passage 123 which
is formed in the above described connecting rod bearing 6.
[0093] Meanwhile, the foreign substance in the lubricating oil also
remains in the partial groove 14 by the depth gradually decreasing
portion 14b, and when the opening of the internal passage 3C which
is formed in the main shaft 3A is located at the depth gradually
decreasing portion 14b thereafter, the foreign substance flows into
the internal passage 3C together with the lubricating oil.
[0094] Thereafter, when the opening at the above described crankpin
3B side in the internal passage 3C communicates with the
lubricating oil discharge passage 123 formed in the above described
connecting rod bearing 6, the foreign substance is discharged
outside the connecting rod 4 via the lubricating oil discharge
passage 123 together with the lubricating oil, and damage to the
crankpin 3B and the connecting rod bearing 6 due to the foreign
substance is prevented.
[0095] As above, in the engine 1 of the present embodiment, the
partial groove 14 is formed in the upper side bearing member 11 of
the main shaft 3A, and the depth gradually decreasing portion 14b
of the partial groove 14 is formed under the conditions of the
above described (expression 1) and (expression 3), whereby most of
the lubricating oil which is supplied to the sliding portion of the
main shaft 3A and the main bearing 5 can be caused to pass into the
internal passage 3C which is formed in the crankshaft 3.
[0096] As a result, the amount of the lubricating oil which is
discharged from the sliding portion of the main shaft 3A and the
main bearing 5 can be suppressed, and because the foreign substance
contained in the lubricating oil can be discharged to the internal
passage 3C, damage to the main shaft 3A and the main bearing 5 can
be prevented.
[0097] Further, the foreign substance contained in the lubricating
oil which is supplied to the above described internal passage 3C is
discharged outside the connecting rod 4 together with the
lubricating oil by the lubricating oil discharge passage 123 which
is formed in the above described connecting rod bearing 6, and
therefore, damage to the crankpin 3B and the connecting rod bearing
6 due to the foreign substance can be also prevented.
[0098] FIG. 8 shows a graph showing an experimental result about
the engine 1 according to the above described second
embodiment.
[0099] As is the case with the first embodiment, the experiment was
performed by operating the engine 1 with the internal passage 3C of
the above described crankshaft 3 being closed, and mixing a
predetermined amount of foreign substance into the lubricating oil
which was supplied from the lubricating oil passage 2A of the above
described cylinder block 2.
[0100] Subsequently, it was measured how much foreign substance
remains in the partial groove 14 which is formed in the upper side
bearing member 11 in the above described main shaft 3A.
[0101] FIG. 8 is the experimental result about expression 3, and
the axis of abscissa represents the angle .theta. formed by the
depth gradually decreasing portion 14b and the inner
circumferential surface of the upper side bearing member 11,
whereas the axis of ordinates represents the ratio of the foreign
substance mixed via the lubricating oil passage 2A being recovered
by the above described partial groove 14. In the experiment of FIG.
8, the distance D between the end portion of the partial groove 14
and the crush relief 11b in expression 1 is set as 2 mm.
[0102] As is understood from FIG. 8, it can be understood that when
the formed angle .theta. is approximately 25.degree. or larger, the
foreign substance favorably remains in the partial groove 14, and
it is predictable that if the internal passage 3C of the above
described crankshaft 3 communicates therewith in this state, the
foreign substance is favorably recovered into the internal passage
3C.
[0103] Further, as shown in the graph, the range of expression 3 is
further desirably set as the range of
30.ltoreq..theta..ltoreq.45.degree..
[0104] In the engine 1 in the first embodiment, the connecting rod
bearing 6 according to the above described second embodiment may be
used, and in the engine 1 in the second embodiment, the connecting
rod bearing 6 according to the above described first embodiment may
be used.
[0105] Further, as the lubricating oil discharge passages 23 and
123 which are formed in the connecting rod bearings 6 in the first
embodiment and the second embodiment, so-called jet holes which are
formed to penetrate through the outer surface of the connecting rod
4 from the inner circumferential surface of the connecting rod
bearing 6 may be adopted in place of the lubricating oil discharge
passages 23 and 123.
REFERENCE SIGNS LIST
[0106] 1 engine
[0107] 2 cylinder block
[0108] 2A lubricating oil passage
[0109] 3 crankshaft
[0110] 3A main shaft
[0111] 3B crankpin
[0112] 3C internal passage
[0113] 4 connecting rod
[0114] 5 main bearing
[0115] 6 connecting rod bearing
[0116] 11 upper side bearing member
[0117] 11a radial hole
[0118] 14 partial groove
[0119] 14b depth gradually decreasing portion
[0120] 21, 22 half-split bearing
[0121] 23 lubricating oil discharge passage
* * * * *