U.S. patent application number 09/921468 was filed with the patent office on 2001-11-22 for valve spring retainer and a valve operating mechanism.
Invention is credited to Abe, Makoto, Kobayashi, Haruki, Sassa, Takeshi.
Application Number | 20010042530 09/921468 |
Document ID | / |
Family ID | 27481148 |
Filed Date | 2001-11-22 |
United States Patent
Application |
20010042530 |
Kind Code |
A1 |
Kobayashi, Haruki ; et
al. |
November 22, 2001 |
Valve spring retainer and a valve operating mechanism
Abstract
A valve spring retainer is mounted to the upper end of a poppet
valve via a pair of cotters in an internal combustion engine of an
automobile. The valve spring retainer has an intermediate portion
and an outer flange which is engaged with the upper end of a valve
spring. The lower surface has a gap between the outer flange and
the intermediate portion to decrease wear which is caused by
engagement with the valve spring. There is also provided a valve
operating mechanism which has a valve spring retainer which has a
projection on the lower surface so as to prevent wear.
Inventors: |
Kobayashi, Haruki;
(Fujisawa-shi, JP) ; Abe, Makoto; (Fujisawa-shi,
JP) ; Sassa, Takeshi; (Fujisawa-shi, JP) |
Correspondence
Address: |
ZARLEY MCKEE THOMTE VOORHEES & SEASE PLC
SUITE 3200
801 GRAND AVENUE
DES MOINES
IA
50309-2721
US
|
Family ID: |
27481148 |
Appl. No.: |
09/921468 |
Filed: |
August 3, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09921468 |
Aug 3, 2001 |
|
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09661713 |
Sep 14, 2000 |
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6293240 |
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Current U.S.
Class: |
123/90.67 ;
123/90.65 |
Current CPC
Class: |
F01L 3/10 20130101 |
Class at
Publication: |
123/90.67 ;
123/90.65 |
International
Class: |
F01L 003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2000 |
JP |
2000-89109 |
Mar 28, 2000 |
JP |
2000-89110 |
Apr 27, 2000 |
JP |
2000-127108 |
Claims
What is claimed is:
1. A valve spring retainer in an internal combustion engine, the
retainer comprising an inner portion which surround a taper bore,
an intermediate portion and an outer flange in which a lower
surface is engaged with an upper end of a valve spring, the lower
surface of the outer flange being formed to provide a gap between
the outer flange and the intermediate portion.
2. A valve spring retainer as claimed in claim 1 wherein the lower
surface of the outer flange is radially inclined downwards to
outside.
3. A valve spring retainer as claimed in claim 1 made of Al
alloy.
4. A valve spring retainer as claimed in claim 2 wherein the lower
surface of the outer flange is inclined at an angle of less than
1.degree..
5. A valve spring retainer as claimed in claim 1 wherein the lower
surface of the outer flange comprises an arc-sectioned annular
projection.
6. A valve spring retainer as claimed in claim 1 wherein an annular
recess is formed on the lower surface around the intermediate
portion.
7. A valve spring retainer as claimed in claim 1 wherein an
inverse-trapezoid-sectioned annular projection is provided on the
lower surface of the outer flange.
8. A valve operating mechanism for reciprocating a poppet valve in
an internal combustion engine, said mechanism comprising: a valve
spring retainer which is mounted to an end of the poppet valve and
has an outer flange; and a valve spring which is provided between a
lower surface of the outer flange and a cylinder head, a downward
projection being partially formed on the lower surface of said
outer flange and inserted in an opening between an end of an
uppermost first winding and an upper surface of a second winding of
the valve spring.
9. A valve operating mechanism as claimed in claim 8 wherein a
lower surface of the projection is inclined at almost the same
angle as that of the second winding.
10. A valve operating mechanism as claimed in claim 8 wherein the
valve spring retainer is made of light alloy, the projection being
made of material harder than the retainer.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates a valve spring retainer and a
valve operating mechanism in an internal combustion engine.
[0002] FIG. 10 is one example of a conventional valve operating
mechanism in an internal combustion engine, in which a valve spring
retainer 3 is mounted at the upper end of a poppet valve 1 by a
pair of cotters 2,2. A valve spring 4 is provided between the lower
surface of an outer flange 3a of the valve spring retainer 3 and a
cylinder head (not shown), so that the poppet valve 1 is always
energized upwards by the valve spring 4.
[0003] The numeral 5 denotes a rocker arm which is engaged on the
axial end of the poppet valve 1 and which is moved up and down by a
rotary cam (not shown), so that the poppet valve 1 is opened and
closed.
[0004] The flange 3a of the valve spring retainer 3 of the valve
operating mechanism has a horizontal lower surface perpendicular to
an axis of the valve spring retainer 3, and is adapted to contact
the upper surface of the valve spring 4 when the valve spring 4 is
equipped.
[0005] It is inevitable to wear the lower surface of the flange 3a
of the retainer 3 owing to relatively rotational or radial movement
of the valve spring 4 caused by vibration when the poppet valve is
seated.
[0006] Especially, in an automobile engine which is accelerated or
decelerated frequently, as illustrated in FIG. 11, when the valve
spring 4 is compressed, the uppermost winding is twisted outwards
as shown by a downward arrow, or the flange 3a is bent upwards by
reaction force to compression as shown by an upward arrow when the
valve spring 4 is compressed.
[0007] In the conventional valve spring retainer 3 in which the
lower inner surface of the flange 3a is horizontal, the inner upper
circumference of the first winding which is horizontal at the upper
end of the valve spring is engaged with the lower surface of the
flange 3a, so that a larger surface pressure is applied.
[0008] Thus, as shown in FIG. 12, at the beginning of operation,
the lower inner portion of the flange 3a locally wears, and
develops outwards as shown by dotted lines. Especially, in the
valve spring retainer 3 made of Al alloy for decreasing weight,
wear develops rapidly.
[0009] Also, owing to vibration in opening and closing of the
poppet valve 1 or surging in the valve spring 4, the flange 3a of
the retainer 3 is rotated with respect to the valve spring 4,
thereby causing contact surfaces to wear away. Especially, in the
Al alloy valve spring retainer 3 for lightening, wear to the valve
spring retainer 3 becomes larger.
[0010] As wear becomes larger, setting load of the valve spring 4
becomes smaller to decrease the maximum rotation speed of surging,
thereby decreasing engine performance. Depending on degree in wear,
it becomes necessary to replace the retainer 3 with a new one.
SUMMARY OF THE INVENTION
[0011] In view of the disadvantages in the prior art, it is an
object of the present invention to provide a valve spring retainer
in which the lower surface of a flange is modified in shape to
decrease wear, thereby increasing durability and reliability.
[0012] It is another object of the present invention to provide a
valve operating mechanism of an internal combustion engine in which
a valve spring retainer is prevented from rotation with respect to
a valve spring to keep wear of the contacting surfaces at
minimum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The features and advantages of the present invention will
become more apparent from the following description with respect to
embodiments as shown in appended drawings wherein:
[0014] FIG. 1 is a central vertical sectional front view of the
first embodiment of a valve spring retainer according to the
present invention;
[0015] FIG. 2 is an enlarged sectional view thereof;
[0016] FIG. 3 is an enlarged sectional view which shows how to
contact the valve spring when it is twisted;
[0017] FIG. 4 is a central vertical sectional front view of the
second embodiment of a valve spring retainer according to the
present invention;
[0018] FIG. 5 is an enlarged sectional view thereof;
[0019] FIG. 6 is an enlarged sectional view of the third embodiment
of a valve spring retainer according to the present invention;
[0020] FIG. 7 is a front elevational view of the first embodiment
of a valve operating mechanism according to the present
invention;
[0021] FIG. 8 is a vertical sectional side view taken along the
line A-A in FIG. 7;
[0022] FIG. 9 is an enlarged front view of the second embodiment of
a valve operating mechanism according to the present invention;
[0023] FIG. 10 is a central vertical sectional front view which
shows a conventional valve operating mechanism;
[0024] FIG. 11 is an enlarged sectional view of a conventional
valve spring retainer which shows how to contact a valve spring
when it is twisted; and
[0025] FIG. 12 is an enlarged front view thereof which shows how to
wear in an outer flange.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] FIG. 1 illustrates the first embodiment of the present
invention, in which a valve spring retainer 6 according to the
present invention is molded by Al alloy such as Al--Si and Al--Cu
and formed by T6 treatment under the Japanese Industrial Standards.
The valve spring retainer 6 comprises an inner portion 6a which
surrounds a taper bore 7, an intermediate portion 6b and an outer
flange 6c which is engaged with the upper end of the valve spring
4. As shown in FIG. 2, the lower surface 8 of the outer flange 6c
is slightly inclined by an angle "a" with respect to a horizontal
line "H" perpendicular to an axis "L" of the valve spring retainer
6.
[0027] The angle ".alpha." is determined by material of the valve
spring retainer 6 or a spring constant or load to be set of the
valve spring. Preferably, an ordinary Al alloy valve spring
retainer for a gasoline engine may have an angle of less than
1.degree..
[0028] The lower surface 8a of the outer flange 6c is radially
inclined downwards toward the outer circumference. When the valve
spring 4 is mounted as shown in FIG. 2, the uppermost winding is
engaged with the lower surface of the outer flange 6c. When the
engine is accelerated and decelerated, the uppermost winding of the
valve spring 4 is compressed and twisted by the valve spring
retainer 6 and the outer flange 6c gives upwards. Then, the
uppermost flat surface of the valve spring 4 is engaged with the
lower surface 8a of the outer flange 6c.
[0029] The inner portion of the outer flange 6c is prevented from
wearing locally. The lower surface is prevented from wearing at
broad extent. As a result, setting load of the valve spring 4
decreases, and decrease in the maximum rotation speed is prevented,
so that engine performance is kept suitable for a long time.
[0030] An angle ".alpha." of the lower surface 8 of the outer
flange 6c may be less than 1.degree. If it is more than 1.degree.,
surface pressure of the portion which contacts the valve spring
will be too high, thereby increasing wear in the circumference of
the lower surface 8.
[0031] The present invention is applied to relatively soft Al alloy
valve spring retainer as mentioned above, but may be applied to an
ordinary steel valve spring retainer.
[0032] In FIGS. 4 and 5, the second embodiment of the present
invention will be illustrated. The lower surface 8b of an outer
flange 6c is formed as an arcuate section. By the second embodiment
of the present invention, similar advantages to the above are
achieved.
[0033] In FIG. 6, the third embodiment of the present invention is
illustrated. The lower surface of an outer flange 8 is formed as an
inverse-trapezoid-section, and an annular recess 9 is formed
between an intermediate portion 6b and the outer flange 6c. The
width of the recess 9 is determined such that the uppermost inner
edge of the valve spring does not get out of the recess 9 even if
the valve spring is moved radially at maximum. In the third
embodiment, if the valve spring is twisted outwards, the inner edge
gets in the recess 9 to form a gap between the outer flange and the
intermediate portion, thereby preventing the lower surface of the
outer flange 6c from wearing locally. In the third embodiment, only
the recess 9 may be formed without projection of the lower surface
8c of the outer flange 6c. To prevent stress from concentrating to
the recess, the recess 9 may have an arc which has relatively large
radius.
[0034] In FIGS. 7 and 8, the first embodiment of a valve operating
mechanism according to the present invention is disclosed. A valve
spring retainer 6 is made of Al alloy, and mounted to the axial end
of a poppet valve 1 via a pair of cotters 2,2. On the lower surface
of an outer flange 6c of the valve spring retainer 6, a projection
11 is partially formed and inserted into an opening "C" which is
formed between the uppermost first winding 1a and the second
winding 4b of the valve spring 4.
[0035] Height and circumference of the projection are determined by
the following way. As shown in FIG. 7, the valve spring retainer 6
is mounted such that the projection 11 is positioned in the opening
"C". The right side of the projection 11 is engaged with the end of
the first winding 4a of the valve spring 4, and the left lower
corner of the projection 11 is positioned closely to the upper
surface of the second winding which is inclined upwards to the
left.
[0036] In the valve operating mechanism of the present invention,
if the valve spring 4 is rotated with respect to the valve spring
retainer 6 around an axis, the right side of the projection 11 is
engaged with the end of the first winding 4a and the left lower
corner is engaged with the upper surface of the second winding
4b.
[0037] Thus, sliding friction between the upper end of the valve
spring 4 and the outer flange 6c almost disappears, thereby greatly
decreasing wear of the valve spring retainer 6 made of Al
alloy.
[0038] FIG. 9 is the second embodiment of a valve operating
mechanism of the present invention, in which the lower surface of a
projection 11 is inclined at almost the same angle as that of a
second winding 4b of a valve spring 4. When the valve spring 4 and
a valve spring retainer 6 are rotated in directions as shown by
arrows respectively, contact area between the lower surface of the
projection 11 and the upper surface of the second winding 4b of the
valve spring 4 increases to decrease surface pressure, thereby
decreasing wear of the contact surfaces.
[0039] The valve operating mechanism according to the present
invention is not limited to the embodiments as above. In the
embodiment, the projection 11 is part of the retainer 6, but may be
separately formed and fixed to an outer flange 6a of a valve spring
retainer 6 by means of welding or a screw. The projection 11 may be
made of hard steel or light Ti alloy to increase wear resistance.
The valve operating mechanism of the present invention may be
applied to what has a steel valve spring retainer.
[0040] The foregoing merely relate to embodiments of the present
invention. Various modifications and changes may be made by person
skilled in the art without departing from the scope of claims
wherein:
* * * * *