U.S. patent application number 15/577467 was filed with the patent office on 2018-05-31 for valve opening/closing timing control device.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. The applicant listed for this patent is AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Takeo ASAHI, Yuji NOGUCHI.
Application Number | 20180149044 15/577467 |
Document ID | / |
Family ID | 57608806 |
Filed Date | 2018-05-31 |
United States Patent
Application |
20180149044 |
Kind Code |
A1 |
NOGUCHI; Yuji ; et
al. |
May 31, 2018 |
VALVE OPENING/CLOSING TIMING CONTROL DEVICE
Abstract
A valve opening/closing timing control device includes a driving
rotary body rotatable in synchronism with a crankshaft of an
internal combustion engine, a driven rotary body rotatable in
unison with a cam shaft of the internal combustion engine and
rotatable also relative to the driving rotary body within this
driving rotary body, a fluid pressure chamber formed by the driving
rotary body and the driven rotary body, and a partitioning portion
that partitions the fluid pressure chamber into an advance chamber
and a retard chamber. The driving rotary body includes an aluminum
housing having a pulley that receives a drive force of the
crankshaft via a drive belt and a plate attached to at least one
face of the housing. Between the housing and the plate, there is
provided a gap allowing outflow of fluid.
Inventors: |
NOGUCHI; Yuji; (Obu-shi,
Aichi, JP) ; ASAHI; Takeo; (Kariya-shi, Aichi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN SEIKI KABUSHIKI KAISHA |
Kariya-shi, Aichi |
|
JP |
|
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi, Aichi
JP
|
Family ID: |
57608806 |
Appl. No.: |
15/577467 |
Filed: |
June 20, 2016 |
PCT Filed: |
June 20, 2016 |
PCT NO: |
PCT/JP2016/068263 |
371 Date: |
November 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01L 2301/00 20200501;
F01L 2001/3443 20130101; F01L 2250/04 20130101; F01L 2001/34479
20130101; F01L 1/024 20130101; F01L 2001/0476 20130101; F01L
2001/34483 20130101; F01L 1/3442 20130101; F01L 1/047 20130101;
F01L 2810/02 20130101; F01L 2001/34433 20130101 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 29, 2015 |
JP |
2015-130150 |
Claims
1. A valve opening/closing control device comprising: a driving
rotary body rotatable in synchronism with a crankshaft of an
internal combustion engine and rotatable also about a rotational
axis; a driven rotary body rotatable in unison with a cam shaft of
the internal combustion engine about the rotational axis and
rotatable also relative to the driving rotary body within this
driving rotary body; a fluid pressure chamber formed by the driving
rotary body and the driven rotary body; a partitioning portion
provided within the fluid pressure chamber for partitioning the
fluid pressure chamber into a retard chamber and an advance chamber
allowing introduction and discharge of fluid thereto/therefrom, the
partitioning portion selectively displacing relative rotation phase
of the driven rotary body relative to the driving rotary body in a
retard direction in which capacity inside the retard chamber is
increased in association with introduction of the fluid or an
advance direction in which capacity inside the advance chamber is
increased in association with introduction of the fluid; the
driving rotary body including an aluminum housing having a pulley
that inputs drive force from the crankshaft via a drive belt and a
plate attached to at least one face of the housing extending along
the rotational axis; and a gap allowing outflow of the fluid
therethrough being provided between the housing and the plate.
2. The valve opening/closing control device of claim 1, wherein the
pulley is subjected to an alumite treatment in advance.
3. The valve opening/closing control device of claim 1, wherein at
least one of a contacting face of the housing and a contacting face
of the plate is provided as an alumite-treated surface having a
predetermined surface roughness; and the contacting face of the
housing and the contacting face of the plate are placed in direct
contact with each other.
4. The valve opening/closing control device of claim 1, wherein:
the partitioning portion is provided in the driven rotary body; the
housing includes a cylindrical wall portion having, in its inner
circumferential face, a sliding contacting area where the housing
comes into sliding contact with the partitioning portion; between
the pulley and the cylindrical wall portion, there is formed a
groove portion that penetrates in the direction of the rotational
axis and extends in a circumferential direction relative to the
rotational axis; and the groove portion and the sliding contacting
area have a mutually overlapped area in a radial direction of the
rotational axis.
5. The valve opening/closing control device of claim 4, wherein a
width of the groove portion along the radial direction of the
rotational axis is set greater than a width of the contacting face
of the housing that comes into contact with the plate along the
radial direction.
Description
TECHNICAL FIELD
[0001] The present invention relates to a valve opening/closing
timing control device configured to adjust ignition timing of an
internal combustion engine, more particularly to such device in
which a driving rotary body having a pulley receiving a drive force
from a crankshaft is formed of aluminum material.
RELATED ART
[0002] Such valve opening/closing timing control device having a
driving rotary body formed of aluminum material is known from e.g.
Patent Document 1. Here, aluminum material is extruded from a mold
and then subjected to a first work for shape adjustment and then
the outer circumferential face and the inner circumferential face
entirely are subjected to an "alumite" (anodized aluminum)
treatment for hardening of the respective surface. According to the
above document, the use of aluminum material allows weight
reduction of the device. Further, as the driving rotary body is
produced by extrusion molding, leak of operating oil from the
inside of the driving rotary body to the pulley formed outside it
can be prevented, thus preventing deterioration of a rubber belt
(see paragraphs [0017], [0193]).
PRIOR-ART DOCUMENT
Patent Document
[0003] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2010-203234
SUMMARY
Problem to be Solved by Invention
[0004] In the case of the technique of Patent Document 1 above,
while the alumite treatment enhances the surface hardness of the
driving rotary body, this treatment also causes deterioration in
the surface roughness of e.g. the pulley tooth portion. Then, if
the coating layer thickness of the alumite treatment is increased
in order to improve the wear resistance of the pulley tooth
portion, this will cause further deterioration in the surface
roughness. As a result, the belt wound around the pulley can be
easily damaged, thus reducing the service life of the belt.
[0005] Further, the pulley is formed to protrude in the radially
outward direction from the main body of the driving rotary body
along the entire circumference thereof. Thus, deformation caused by
the tension of the belt can be transmitted to the main body of the
driving rotary body, which may cause deformation of this main body.
The inner circumferential face of this main body is exposed to
sliding contact with vanes provided in the driven rotary body for
forming advance chambers and retard chambers. Therefore, such
deformation of the main body leads to deterioration in the contact
condition of the vanes, which may lead to inadvertent establishment
of communication between an advance chamber and a retard chamber,
so that precision control of valve opening/closing timing may
become impossible.
[0006] Further, the main body formed integral with the pulley and
the front and rear plates are fastened to each other with use of a
bolt. Then, the fastening force of the bolt may be applied to the
contacting face between the respective plate and the main body,
which can cause deformation in the main body. Consequently, the
pulley may be deformed to cause deterioration in the tooth portion
precision, thus resulting possibly in further reduction of the
service life of the drive belt or noise generation by the drive
belt.
[0007] In view of the situation described above, there is a need
for such valve opening/closing timing control device that uses
aluminum material, but allows high precision in the phase control
and longer service life of the belt.
Solution
[0008] According to a characterizing feature of the present
invention, a valve opening/closing control device comprises:
[0009] a driving rotary body rotatable in synchronism with a
crankshaft of an internal combustion engine and rotatable also
about a rotational axis;
[0010] a driven rotary body rotatable in unison with a cam shaft of
the internal combustion engine about the rotational axis and
rotatable to the driving rotary body within this driving rotary
body;
[0011] a fluid pressure chamber formed by the driving rotary body
and the driven rotary body;
[0012] a partitioning portion provided within the fluid pressure
chamber for partitioning the fluid pressure chamber into a retard
chamber and an advance chamber allowing introduction and discharge
of fluid thereto/therefrom, the partitioning portion selectively
displacing relative rotation phase of the driven rotary body
relative to the driving rotary body in a retard direction in which
capacity inside the retard chamber is increased in association with
introduction of the fluid or an advance direction in which capacity
inside the advance chamber is increased in association with
introduction of the fluid;
[0013] a phase control section that controls either feeding of the
fluid to the retard chamber and discharging of the fluid from the
advance chamber, or discharging of the fluid from the retard
chamber and feeding of the fluid to the advance chamber;
[0014] the driving rotary body including an aluminum housing having
a pulley that inputs drive force from the crankshaft via a drive
belt and a plate attached to at least one face of the housing
extending along the rotational axis; and
[0015] a gap allowing outflow of the fluid therethrough being
provided between the housing and the plate.
[0016] In case the pulley and the housing of the driving rotary
body are formed of aluminum material, due to relative softness of
the material per se, frictional wear tends to occur in the pulley
resulting from its contact with the drive belt.
[0017] In view of the above, in the inventive arrangement above,
between the housing and the plate, there is provided a gap that
allows outflow of fluid therethrough. With this arrangement, the
fluid flows out via this gap in association with rotation of the
driving rotary body and this fluid will flow to the outer side by
the centrifugal force. This fluid will reach the pulley disposed
outside the housing and the drive belt wound around this pulley,
thus lubricating the contact portion between the pulley and the
drive belt. In this way, with the above inventive arrangement, it
is possible to obtain a valve opening/closing timing control device
that can reduce frictional wear of the pulley and the drive belt,
thus being reliable in its operation.
[0018] According to a further arrangement, preferably, the pulley
is subjected to an alumite treatment in advance.
[0019] With such alumite treatment of the pulley, the surface
strength of the pulley can be increased. However, while the alumite
treatment provides enhancement of the surface strength of the
pulley, the surface shape of the pulley can be roughened with
growth of alumite layer, thus becoming more aggressive to the drive
belt wound around this pulley. Notwithstanding, since friction
between the drive belt and the pulley is lessened by the fluid fed
via the gap, the reliability of the valve opening/closing timing
control device will not be impaired.
[0020] According to a further arrangement, preferably, at least one
of a contacting face of the housing and a contacting face of the
plate is provided as an alumite-treated surface having a
predetermined surface roughness; and the contacting face of the
housing and the contacting face of the plate are placed in direct
contact with each other.
[0021] As described above, fluid is caused to outflow through the
gap between the housing and the plate. Therefore, with the
inventive arrangement above, at least one of the housing and the
plate is formed of aluminum material and at least one of the
mutually contacting faces thereof is provided as an alumite-treated
face. Namely, the surface roughness of the contacting face is
increased by the alumite treatment and the gap is formed by the
direct contact between the housing and the plate. Moreover, thanks
to the increased strength of the contacting face having the alumite
treatment, deformation in the driving rotary member can be
prevented. Thus, it becomes possible to obtain a valve
opening/closing timing control device having higher
reliability.
[0022] With the above-described provision of the alumite treatment
to at least one of the housing and the plate, a driving rotary body
allowing the outflow of fluid can be formed in an efficient manner.
In particular, in the case of providing the alumite treatment to
the contacting face of the housing, it is possible to provide the
alumite treatment to the pulley and this contacting face
simultaneously, whereby the efficiency of the work for forming the
gap can be further improved. Further, since the housing and the
plate are caused to come into direct contact with each other, there
is no need to provide e.g. a sealing member therebetween. So, the
configuration of the driving rotary body can be made simple.
[0023] According to a further arrangement, preferably:
[0024] the partitioning portion is provided in the driven rotary
body;
[0025] the housing includes a cylindrical wall portion having, in
its inner circumferential face, a sliding contacting area where the
housing comes into sliding contact with the partitioning
portion;
[0026] between the pulley and the cylindrical wall portion, there
is formed a groove portion that penetrates in the direction of the
rotational axis and extends in a circumferential direction relative
to the rotational axis; and
[0027] the groove portion and the sliding contacting area have a
mutually overlapped area in a radial direction of the rotational
axis.
[0028] An aluminum housing is softer than a steel housing, so some
deformation can occur therein when the drive force from the
crankshaft is inputted to the pulley via the drive belt. As a
result, for instance, some warping may occur in the cylindrical
wall portion of the housing, which in turn can lead to formation of
a gap between the partitioning portion and the inner
circumferential face of the cylindrical wall portion, which face
should come into sliding contact with the partitioning portion.
Such gap if formed results in inadvertent leakage of the fluid
between the advance chamber and the retard chamber, thus leading
eventually to imprecision in the phase control of the valve
opening/closing timing control device.
[0029] In view of the above, in the inventive arrangement above,
between the pulley and the cylindrical wall portion, there is
provided a groove portion that penetrates in the direction of the
rotational axis and extends in a circumferential direction relative
to the rotational axis and the groove portion and the sliding
contacting area have a mutually overlapped area in a radial
direction of the rotational axis. With this, even when deformation
occurs in the pulley, it is still possible to prevent this
deformation from being transmitted to the cylindrical wall portion
of the housing.
[0030] As a result, it becomes possible to obtain a valve
opening/closing timing control device that can effect precise phase
control.
[0031] According to a further arrangement, preferably, a width of
the groove portion along the radial direction of the rotational
axis is set greater than a width of the contacting face of the
housing that comes into contact with the plate along the radial
direction.
[0032] In the above arrangement, the housing is formed by extrusion
molding of an aluminum material for instance. Therefore, with
setting of the width of the groove portion to the width defined in
the above arrangement, the pulley can be formed with a
predetermined outside diameter by locating the position of the
pulley on the outer side of the outer face of the cylindrical wall
portion and also the extrusion amount of the aluminum material can
be reduced by the amount corresponding to the groove portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a side view in section of a valve opening/closing
timing control device according to an embodiment,
[0034] FIG. 2 is a plane view in section of the valve
opening/closing timing control device according to the embodiment,
and
[0035] FIG. 3 is an exploded perspective view of a driving rotary
body in the embodiment.
EMBODIMENTS
[0036] [General Configuration]
[0037] Next, an embodiment of the present invention will be
explained with reference to the accompanying drawings.
[0038] A valve opening/closing timing control device relating to
this embodiment is shown in FIGS. 1 through 3. FIG. 1 is a side
view in section of the inventive device. FIG. 2 is a plane view in
section of the same and FIG. 3 is an exploded perspective view of a
driving rotary body.
[0039] The valve opening/closing timing control device consists
mainly of a driving rotary body A (an outer rotor) rotatable in
synchronism with a crankshaft Z of an internal combustion engine
and rotatable also about a rotational axis X, a driven rotary body
B (an inner rotor) mounted within the driving rotary body A and
rotatable in unison with a cam shaft C of the internal combustion
engine about the rotational axis X, and a phase control section for
adjusting a relative rotation phase between the driving rotary body
A and the driven rotary body B.
[0040] Between the driving rotary body A and the driven rotary body
B, a fluid pressure chamber R is formed. A first protruding portion
1 protruding inwards from the driving rotary body A on the outer
side comes into contact with an outer circumferential face B1 of
the driven rotary body B disposed on the inner side; and a second
protruding portion 2 protruding from the outer circumferential face
B1 of the driven rotary body B comes into contact with an inner
circumferential face W1 of the driving rotary body A. These first
protruding portion 1 and second protruding portion 2 function as
"partitioning portions" of the fluid pressure chamber R and
partition the fluid pressure chamber R into an advance chamber R1
and a retard chamber R2.
[0041] In operation, when operating fluid is fed to the advance
chamber R1 via an advance oil passage 3 and operating fluid is
discharged from the retard chamber R2 via a retard oil passage 4,
the driven rotary body B is relatively rotated in the clockwise
direction in FIG. 2. As a result, the valve opening/closing timing
of the internal combustion engine is advanced. For instance, such
an advance operation as above is effected for e.g. increasing the
rotational speed of the internal combustion engine. On the other
hand, when the operating fluid is fed to the retard chamber R2 and
the operating fluid is discharged from the advance chamber R1, the
driven rotary body B is relatively rotated in the counterclockwise
direction in FIG. 2. As a result, the valve opening/closing timing
of the internal combustion engine is retarded (delayed). This
latter operation is effected for e.g. decreasing the rotational
speed of the internal combustion engine, and an operation with
idling rotation will be effected in a most retarded phase.
[0042] [Housing]
[0043] In this embodiment, a housing H of the driving rotary body A
is formed of an aluminum material. This driving rotary body A
consists mainly of three components; namely, the housing H
integrally forming a pulley P in its outer circumferential portion,
a front plate FP and a rear plate RP which sandwich this housing H
from the opposed sides thereof. These components are assembled
together with using a plurality of fastening bolts 5. The housing
H, as shown in FIG. 3, has a substantially constant cross sectional
shape as seen in a section along the fastening direction and is
produced by extrusion molding of the aluminum material.
Incidentally, as an alternative arrangement to the above, it is
possible to mold the front plate FP or the rear plate RP integrally
with the housing H. In such case, the production can be made by
e.g. die-casting technique.
[0044] In particular, the housing H includes the pulley P formed on
the outer circumferential side and a cylindrical wall portion W
formed on its inner circumferential side and accommodating the
driven rotary body B. This cylindrical wall portion W includes an
inner circumferential face W1 which comes into sliding contact with
the second protruding portion 2 formed in the driven rotary body B.
Further, the cylindrical wall portion W includes a plurality of
first protruding portions 1 which come into sliding contact with
the outer circumferential face B1 of the driven rotary body B.
[0045] As shown in FIG. 2, on the outer circumferential side of the
cylindrical wall portion W, the pulley P is integrally formed in
such a manner that most of it is spaced from the cylindrical wall
portion W. The cylindrical wall portion W and the pulley P are
connected at connecting portions 6 provided at same positions as
the first protruding portions 1 provided at four positions in
distribution along the circumferential direction.
[0046] With the above-described arrangement of the cylindrical wall
portion W and the pulley P being assembled and formed integrally
with each other, in comparison with an arrangement of these two
parts being provided separately and connected as such to each
other, the above arrangement advantageously eliminates trouble of
an alignment operation for them. Further, the arrangement
eliminates also the fastening bolts 5 for integrating them together
and the fastening operation per se too can be eliminated. Thus,
such advantages as weight reduction and cost reduction can be
achieved.
[0047] [Bolt Fastening]
[0048] As shown in FIG. 2 and FIG. 3, a bolt hole 7 formed in the
housing H for allowing insertion of the fastening bolt 5 is
provided at a center position of the respective first protruding
portion 1. With this arrangement, it is possible to secure a large
contact area between the front plate FP or the rear plate RP and
the housing H and to avoid application of locally concentrated load
to the housing H at the time of fastening of the fastening bolt 5.
Consequently, the arrangement can lessen the possibility of
deforming of the front plate FP, the rear plate RP and the housing
H. Thus, it becomes possible to prevent unnecessary leakage of the
operating fluid held within the fluid pressure chamber R to the
outside from e.g. a gap between the front plate FP and the housing
H.
[0049] Incidentally, the front plate FP and the rear plate RP too
can be formed of aluminum material. In the case of such
arrangement, the driving rotary body A can be formed further
light-weighted. Incidentally, in case the rear plate RP is formed
of aluminum material, a female thread portion 8 to which the
fastening bolt 5 engages can be formed slightly longer, so as to
prevent damage of this female thread portion 8 by the fastening
force.
[0050] Also, the position of the female thread portion 8 is a
position between the first protruding portion 1 and the connecting
portion 6 along the radial direction. More specifically, this is a
position slightly offset toward the first protruding portion 1.
With this position setting, when the second protruding portion 2 of
the driven rotary body B reaches the most advanced phase and the
most retarded phase to come into contact with the first protruding
portion 1, bending deformation of the first protruding portion 1
can be avoided. Incidentally, in the case of the example shown in
FIG. 2, the arrangement is made such that only the second
protruding portion 2 located at the left upper side in FIG. 2 will
come into contact with the first protruding portion 1.
[0051] [Alumite Treatment]
[0052] In case the pulley P and the housing H of the driving rotary
body A are formed of aluminum material which is a relatively soft
material, frictional wear tends to occur in the pulley P due to its
friction with the drive belt V. Then, for this driving rotary body
A, in order to enhance the hardness of its surface, an anodizing
oxidization treatment, alias, an alumite treatment, is effected.
Specifically, this treatment is given to the tooth portion of the
pulley P and the lateral face of the cylindrical wall portion
W.
[0053] However, the alumite treatment causes deterioration in the
surface roughness of the treated surface. For this reason, there
will occur aggressiveness such as increased friction coefficient
relative to the drive belt V, so that reduction in the service life
of the drive belt V may result to the contrary.
[0054] [Gap]
[0055] Then, in this embodiment, as shown in FIG. 1 and FIG. 3, an
arrangement is provided such that operating fluid for the sake of
lubrication may be fed to the drive belt V through a gap between
the housing H and the front plate FP and the rear plate RP.
[0056] More particularly, between the housing H and the front plate
FP and the rear plate RP, gaps G are provided which allow outflow
of oil as the operating fluid. Such gaps G are formed e.g. by
increasing the surface roughness of a contacting face W2, which is
a surface of the housing H that comes into contact with the front
plate FP or the rear plate RP, by means of the above-described
alumite treatment.
[0057] The contacting face W2 of the housing H is brought into
direct contact with a contacting face FP1 of the front plate FP or
a contacting face RP1 of the rear plate RP each other.
[0058] With the above-described arrangement, in association with
rotation of the driving rotary body A, an appropriate amount of oil
will outflow through the gap and will flow to the outer side by the
centrifugal force. This flowing oil will reach the pulley P
disposed on the outer side of the housing H and the drive belt V
wound around the pulley P, thus lubricating the pulley P and the
drive belt V. Needless to say, the drive belt V used should be made
of material suitable for the oil lubrication.
[0059] Further, with the alumite treatment of the contacting face
W2, the surface hardness of this contacting face W2 is enhanced.
Therefore, at the time of fastening with the front plate FP and the
rear plate RP, even if the fastening force of the fastening bolt 5
is too strong, deformation of the cylindrical wall portion W can be
prevented.
[0060] Further, with the above-described arrangement, there is no
need to provide special sealing material between the cylindrical
wall portion W and the front plate FP or the rear plate RP, so the
configuration of the driving rotary body A can be simplified.
[0061] In this way, with the driving rotary body A having the
above-described arrangement, the configuration of the driving
rotary body A can be simplified and at the same time frictional
wear of the pulley P and the drive belt V can be reduced.
Consequently, it is possible to obtain a valve opening/closing
timing control device which is highly reliable.
[0062] Incidentally, for the purpose of forming the gap G, the
front plate FP or the rear plate RP may be formed of aluminum
material and the contacting face FP1 of the front plate FP or the
contacting face RP1 of the rear plate RP may be subjected to
alumite treatment for enhancing the surface roughness of these
faces.
[0063] [Groove Portion]
[0064] In the driving rotary body A used in this embodiment,
between the pulley P and the cylindrical wall portion W, there are
formed groove portions 9 that penetrate in the direction of the
rotational axis X and extend in the circumferential direction
relative to the rotational axis X. In the case of the example shown
in FIG. 2, such groove portions 9 are formed over all entire
regions other than those of the connecting portions 6 which connect
the cylindrical wall portion W and the pulley P.
[0065] Each end portion of the groove portion 9 in the
circumferential direction extends to reach a more center side of
the first protruding portion 1 than the lateral face of this first
protruding portion 1. Namely, a circumferential length of the
respective connecting portion 6 which is the region sandwiched
between two adjacent groove portions 9 is set shorter than the
circumferential length of the first protruding portion 1
corresponding to the respective connecting portion 6. The reason
for this is as follows. Namely, by securing a large area for the
groove portion 9 relative to the region where the second protruding
portion 2 of the driven rotary body B comes into sliding contacting
with the inner circumferential face W1 of the cylindrical wall
portion W, even if deformation should occur in the pulley P by the
drive belt V, the position where such deformation is transmitted to
the cylindrical wall portion W can be set away from the sliding
contacting region of the second protruding portion 2.
[0066] Incidentally, the circumferential length of the groove
portion 9 need not necessarily be longer than the circumferential
length of the sliding contacting region of the second protruding
portion 2. For, such effect of preventing transmission of
deformation of the pulley P to the cylindrical wall portion W can
be achieved as long as there is present, even of a very small
amount, a region where the groove portion 9 and the sliding
contacting region are overlapped with each other along the radial
direction of the rotational axis X.
[0067] Further, with formation of such groove portions 9 above,
when there occurs rise of temperature in the driving rotary body A
in the course of operation of the internal combustion engine, such
heat will less likely be conducted to the pulley P. Therefore, heat
deterioration of the drive belt V can be prevented. First of all,
the provision of the groove portions 9 can achieve reduction in the
amount of aluminum material used as well as weight reduction of the
driving rotary body A.
[0068] On the other hand, as for a width 9a of the groove portion 9
in the radial direction, this can vary in size in many ways.
Basically, by proving the groove portion 9 to render the
cylindrical wall portion W and the pulley P away from each other in
the radial direction, this will make deformation in the pulley P to
be transmitted less likely to the cylindrical wall portion W.
However, advantageously, this width 9a of the groove portion 9 will
be formed greater than a width W3 of the contacting face W2 of the
housing H.
[0069] The housing H in this arrangement is formed by extrusion
molding of the aluminum material. Therefore, by setting the width
9a of the groove portion 9 greater than the width W3 of the
contacting face W2, it becomes possible to locate the position of
the pulley P on the radially outer side from the outer face of the
cylindrical wall portion W, thus forming the pulley P of a
predetermined outside diameter and also to reduce the extrusion
amount of the aluminum material by the amount corresponding to the
groove portion 9. In this, if the width 9a of the groove portion 9
is too short, the portion corresponding to the groove portion 9 at
the time of extrusion molding will become too narrow, thus making
the molding difficult and causing reduction in the service life of
the mold also. Then, by setting the width 9a of the groove portion
9 greater than the width W3 of the contacting face W2, the sizes of
the mold will become appropriate, so that an extrusion mold that
can be readily manufactured and that has good durability can be
obtained. With appropriate setting of the width 9a of the groove
portion 9, extrusion resistance experienced by the aluminum
material in the course of extrusion molding will be reduced and the
manufacture efficiency will improve.
[0070] Moreover, with the setting of the width 9a of the groove
portion 9 greater than the width W3 of the contacting face W2, when
e.g. the front plate FP is to be bolt-fastened to the cylindrical
wall portion W, transmission of the fastening force applied to the
cylindrical wall portion W to the pulley P beyond the connecting
portion 6 can be prevented. Therefore, the shape of the pulley P
can be maintained as a true circle, so no rotational shake will
occur, and damage to the drive belt V can be prevented.
Other Embodiments
[0071] Not only the housing H, but also the front plate FP and the
rear plate RP can be formed of aluminum material.
[0072] With the above-described arrangement, there is achieved
significant reduction in the weight of the driving rotary body A.
In such arrangement, however, the female thread portion 8 of the
rear plate RP used for fixing the fastening bolt 5 should have a
necessary length along the longitudinal direction of the fastening
bolt 5 in order to be able to withstand sufficient fastening
torque.
[0073] As the "gap" provided between the cylindrical wall portion W
and the front plate FP or between the cylindrical wall portion W
and the rear plate RP, a recess extending in the radial direction
relative to the cylindrical wall portion W, the front plate FP or
the rear plate RP can be provided. Such recess can be formed by
cutting, molding or embossing. With the recess formed as such, it
is possible to freely set the outflow position and/or outflow
amount of the oil, so that more accurate lubricating effect can be
achieved.
INDUSTRIAL APPLICABILITY
[0074] The present invention is widely applicable to various kinds
of valve opening/closing timing control device configured to effect
phase control by feeding/discharging of operating fluid.
DESCRIPTION OF REFERENCE MARKS/NUMERALS
[0075] 1: first protruding portion (partitioning portion) [0076] 2:
second protruding portion (partitioning portion) [0077] 9: groove
portion [0078] A: driving rotary body [0079] B: driven rotary body
[0080] C: cam shaft [0081] FP: front plate [0082] FP1: contacting
face of front plate [0083] RP: rear plate [0084] RP1: contacting
face of rear plate [0085] H: housing [0086] P: pulley [0087] R:
fluid pressure chamber [0088] R1: advance chamber [0089] R2: retard
chamber [0090] V: drive belt [0091] W: cylindrical wall portion
[0092] W1: inner circumferential face [0093] W2: contacting face of
housing [0094] X: rotational axis [0095] Z: crank shaft
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