U.S. patent application number 10/875736 was filed with the patent office on 2005-02-03 for variable valve timing control device.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Eguchi, Katsuhiko, Kobayashi, Masaki, Ogawa, Kazumi.
Application Number | 20050022763 10/875736 |
Document ID | / |
Family ID | 33411081 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050022763 |
Kind Code |
A1 |
Kobayashi, Masaki ; et
al. |
February 3, 2005 |
Variable valve timing control device
Abstract
A variable valve timing control device includes a housing
member, a rotor member assembled to the housing member so as to be
rotatable relative thereto and including vane portions each forming
an advanced angle chamber and a retarded angle chamber within the
housing member, a stopper formed on the convex portion for defining
a relative rotation between the housing member and the rotor
member, a lock mechanism for restricting the relative rotation by a
lock member, and a fluid pressure circuit for controlling an
operation oil to be supplied to or discharged from the advanced
angle chamber, the retarded angle chamber, and the lock mechanism.
When the relative rotation is restricted, the lock member is in
contact with an inner peripheral face of the receiving hole on the
advanced angle side and the retarded angle side between an opening
portion and a bottom portion of the receiving hole.
Inventors: |
Kobayashi, Masaki;
(Toyota-shi, JP) ; Eguchi, Katsuhiko; (Kariya-shi,
JP) ; Ogawa, Kazumi; (Toyota-shi, JP) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
Kariya-shi
JP
|
Family ID: |
33411081 |
Appl. No.: |
10/875736 |
Filed: |
June 25, 2004 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 2001/34453
20130101; F01L 1/3442 20130101; F01L 2001/34483 20130101 |
Class at
Publication: |
123/090.17 |
International
Class: |
F01L 001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2003 |
JP |
2003-181475 |
Claims
1. A variable valve timing control device comprising: a housing
member integrally rotating with one of a crankshaft and a camshaft
of an internal combustion engine; a rotor member assembled to the
housing member so as to be rotatable relative thereto and being
slidable on a convex portion formed on the housing member, the
rotor member including vane portions each forming an advanced angle
chamber and a retarded angle chamber within the housing member, the
rotor member integrally rotating with the other one of the
crankshaft and the camshaft; a stopper formed on the convex portion
and being in contact with at least one of the vane portions for
defining a relative rotation between the housing member and the
rotor member to an advanced angle side or a retarded angle side; a
lock mechanism for restricting the relative rotation between the
housing member and the rotor member by a lock member disposed on
the housing member to be inserted into a receiving hole formed on
the rotor member when a relative rotation phase between the housing
member and the rotor member is positioned at a predetermined phase;
and a fluid pressure circuit for controlling an operation oil to be
supplied to or discharged from the advanced angle chamber, the
retarded angle chamber, and the lock mechanism; wherein when the
relative rotation between the housing member and the rotor member
is restricted, the lock member is in contact with an inner
peripheral face of the receiving hole on the advanced angle side
and the retarded angle side between an opening portion and a bottom
portion of the receiving hole.
2. A variable valve timing control device comprising: a housing
member integrally rotating with one of a crankshaft and a camshaft
of an internal combustion engine; a rotor member assembled to the
housing member so as to be rotatable relative thereto and being
slidable on a convex portion formed on the housing member, the
rotor member including vane portions each forming an advanced angle
chamber and a retarded angle chamber within the housing member, the
rotor member integrally rotating with the other one of the
crankshaft and the camshaft; a stopper formed on the convex portion
and being in contact with at least one of the vane portions for
defining a relative rotation between the housing member and the
rotor member to an advanced angle side or a retarded angle side; a
lock mechanism for restricting the relative rotation between the
housing member and the rotor member by a lock member disposed on
the housing member to be inserted into a receiving hole formed on
the rotor member when a relative rotation phase between the housing
member and the rotor member is positioned at a predetermined phase;
and a fluid pressure circuit for controlling an operation oil to be
supplied to or discharged from the advanced angle chamber, the
retarded angle chamber, and the lock mechanism; wherein when the
relative rotation between the housing member and the rotor member
is restricted, a contact width in a circumferential direction of a
contact portion of the lock member, with which an inner peripheral
face of the receiving hole on the advanced angle side and the
retarded angle side is in contact, is larger than a bottom width in
the circumferential direction of a bottom portion of the receiving
hole.
3. A variable valve timing control device according to claim 1,
wherein when the relative rotation between the housing member and
the rotor member is restricted, a gap is formed between the stopper
and the vane portion.
4. A variable valve timing control device according to claim 2,
wherein when the relative rotation between the housing member and
the rotor member is restricted, a gap is formed between the stopper
and the vane portion.
5. A variable valve timing control device according to claim 3,
wherein the lock member includes a head portion facing the bottom
portion of the receiving hole and having a trapezoidal shape in
cross section formed by a convex taper portion extending in a
radially inward direction of the housing member and a top portion
including a contact portion with which the inner peripheral face of
the receiving hole is in contact.
6. A variable valve timing control device according to claim 4,
wherein the lock member includes a head portion facing the bottom
portion of the receiving hole and having a trapezoidal shape in
cross section formed by a convex taper portion extending in a
radially inward direction of the housing member and a top portion
including a contact portion with which the inner peripheral face of
the receiving hole is in contact.
7. A variable valve timing control device according to claim 5,
wherein the inner peripheral face of the receiving hole includes a
concave taper portion having a trapezoidal shape in cross section
and gradually expanding towards the opening portion of the
receiving hole.
8. A variable valve timing control device according to claim 6,
wherein the inner peripheral face of the receiving hole includes a
concave taper portion having a trapezoidal shape in cross section
and gradually expanding towards an opening portion of the receiving
hole.
9. A variable valve timing control device according to claim 7,
wherein the contact portion of the head portion of the lock member
and the concave taper portion of the inner peripheral face of the
receiving hole are in contact with each other on the advanced angle
side and the retarded angle side when the relative rotation between
the housing member and the rotor member is restricted.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Application 2003-181475, filed
on Jun. 25, 2003, the entire content of which is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] This invention generally relates to a variable valve timing
control device. More particularly, the present invention pertains
to a variable valve timing control device for controlling an
opening and closing timing of an intake valve and exhaust valve of
an internal combustion engine.
BACKGROUND
[0003] Known variable valve timing control devices are disclosed in
Japanese Patent Nos. 3266013 and 3146956. The disclosed variable
valve timing control devices each include a housing member
integrally rotating with one of a crankshaft and a camshaft of an
internal combustion engine, a rotor member assembled to the housing
member so as to be rotatable relative thereto and being slidable on
a convex portion formed on the housing member. The rotor member
includes vane portions each forming an advanced angle chamber and a
retarded angle chamber within the housing member, and integrally
rotating with the other one of the crankshaft and the camshaft. The
variable valve timing control device also includes a stopper formed
on the convex portion and being in contact with at least one of the
vane portions for defining the relative rotation between the
housing member and the rotor member to an advanced angle side or a
retarded angle side. The variable valve timing control device
further includes a lock mechanism for restricting the relative
rotation between the housing member and the rotor member by a lock
member disposed on the housing member to be inserted into a
receiving hole formed on the rotor member when a relative rotation
phase between the housing member and the rotor member is positioned
at a predetermined phase, and a fluid pressure circuit for
controlling an operation oil to be supplied to or discharged from
the advanced angle chamber, the retarded angle chamber, and the
lock mechanism.
[0004] According to the variable valve timing control device
disclosed in Japanese Patent No. 3266013, when the lock member is
in contact with an opening edge portion of a receiving hole within
which the lock member is positioned, plastic flow of material
forming the receiving hole may be caused due to tangential stress.
Then, the opening edge portion may be raised towards the housing
member side. Further, the opening edge portion being raised may
interfere with the relative rotation between the housing member and
the rotor member. In order to address the above problem, the lock
member includes an engaging taper face on a side of the receiving
hole while the receiving hole includes a guiding taper face
gradually expanding towards an opening side of the receiving hole.
The lock member is in contact with an inner peripheral face of the
receiving hole under the condition that a taper angle of the
guiding taper face is larger than that of the engaging taper face.
Then, the plastic flow may be prevented from occurring in the
opening edge portion of the receiving hole.
[0005] In addition, according to the variable valve timing control
device disclosed in Japanese Patent No. 3146956, a clearance is
formed between the lock member and the receiving hole considering a
receiving performance of the lock member in the receiving hole.
When the advanced angle chamber or the retarded angle chamber is
not sufficiently supplied with the operation fluid from an oil pump
at a time of an engine start, the rotor member and the housing
member starts rotating relative to each other due to the
fluctuation torque of the cam being applied. At this time, since
the clearance is formed between the lock member and the receiving
hole, an inner periphery of the receiving hole and an outer
periphery of the lock member may become in contact with each other
repeatedly, thereby causing a hitting sound. In order to address
the above problem, a taper face is formed on at least one of the
lock member and the receiving hole being in contact with each
other. Then, a biasing force to bias the rotor member in the
rotational direction is generated in the housing member to strongly
press the stopper and the vane portion to each other so that the
rotor member and the housing member are constrained at a locked
position.
[0006] According to the variable valve timing control device
disclosed in Japanese Patent No. 3266013, the lock member can be in
contact with the inner circumferential face of the receiving face.
However, a clearance may be formed between the lock member and the
receiving hole, which causes a looseness therebetween. Further, the
hitting sound due to the looseness may occur.
[0007] In addition, according to the variable valve timing control
device disclosed in Japanese Patent No. 3146956, the rotor member
and the housing member are constrained at the locked position and
thus the lock member may not be able to move from the receiving
hole.
[0008] Thus, a need exists for a variable valve timing control
device which can prevent an occurrence of hitting sound due to a
relative rotation between a lock member and a receiving hole in
case of the relative rotation being locked.
[0009] A need also exists for a variable valve timing control
system in which the lock member is prevented from being constrained
in the receiving hole when the locked state of the relative
rotation is released.
SUMMARY OF THE INVENTION
[0010] According to an aspect of the present invention, a variable
valve timing control device includes a housing member integrally
rotating with one of a crankshaft and a camshaft of an internal
combustion engine, and a rotor member assembled to the housing
member so as to be rotatable relative thereto and being slidable on
a convex portion formed on the housing member, the rotor member
including vane portions each forming an advanced angle chamber and
a retarded angle chamber within the housing member, the rotor
member integrally rotating with the other one of the crankshaft and
the camshaft. The variable valve timing control device also
includes a stopper formed on the convex portion and being in
contact with at least one of the vane portions for defining a
relative rotation between the housing member and the rotor member
to an advanced angle side or a retarded angle side, a lock
mechanism for restricting the relative rotation between the housing
member and the rotor member by a lock member disposed on the
housing member to be inserted into a receiving hole formed on the
rotor member when a relative rotation phase between the housing
member and the rotor member is positioned at a predetermined phase,
and a fluid pressure circuit for controlling an operation oil to be
supplied to or discharged from the advanced angle chamber, the
retarded angle chamber, and the lock mechanism. When the relative
rotation between the housing member and the rotor member is
restricted, the lock member is in contact with an inner peripheral
face of the receiving hole on the advanced angle side and the
retarded angle side between an opening portion and a bottom portion
of the receiving hole.
[0011] According to another aspect of the prevent invention, a
variable valve timing control device includes a housing member
integrally rotating with one of a crankshaft and a camshaft of an
internal combustion engine, and a rotor member assembled to the
housing member so as to be rotatable relative thereto and being
slidable on a convex portion formed on the housing member, the
rotor member including vane portions each forming an advanced angle
chamber and a retarded angle chamber within the housing member, the
rotor member integrally rotating with the other one of the
crankshaft and the camshaft. The variable valve timing control
device also includes a stopper formed on the convex portion and
being in contact with at least one of the vane portions for
defining a relative rotation between the housing member and the
rotor member to an advanced angle side or a retarded angle side, a
lock mechanism for restricting the relative rotation between the
housing member and the rotor member by a lock member disposed on
the housing member to be inserted into a receiving hole formed on
the rotor member when a relative rotation phase between the housing
member and the rotor member is positioned at a predetermined phase,
and a fluid pressure circuit for controlling an operation oil to be
supplied to or discharged from the advanced angle chamber, the
retarded angle chamber, and the lock mechanism. When the relative
rotation between the housing member and the rotor member is
restricted, a contact width in a circumferential direction of a
contact portion of the lock member, with which an inner peripheral
face of the receiving hole on the advanced angle side and the
retarded angle side is in contact, is larger than a bottom width in
the circumferential direction of a bottom portion of the receiving
hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing and additional features and characteristics of
the present invention will become more apparent from the following
detailed description considered with reference to the accompanying
drawings, wherein:
[0013] FIG. 1 is a longitudinal sectional view of a variable valve
timing control device according to an embodiment of the present
invention;
[0014] FIG. 2 is a cross-sectional view taken along the ling A-A of
FIG. 1;
[0015] FIG. 3 is an enlarged view of E portion of FIG. 2; and
[0016] FIG. 4 is an enlarged view of F portion of FIG. 3.
DETAILED DESCRIPTION
[0017] An embodiment of the present invention is explained
referring to attached drawings. A variable valve timing control
device 1 shown in FIGS. 1 to 3 includes a rotor member 2 for
opening/closing a valve, which includes a camshaft 10 rotatably
supported on a cylinder head 100 of an internal combustion engine
and an inner rotor 20 integrally fixed to a tip end portion of the
camshaft 10. The variable valve timing control device 1 also
includes a housing member 3 having an outer rotor 30 being
rotatable relative to the inner rotor 20 within a predetermined
range, a front plate 40, and a rear plate 50. A timing sprocket 31
is integrally formed on an outer periphery of the outer rotor 30.
Further, the variable valve timing control device 1 includes a
torsion spring 60 disposed between the inner rotor 20 and the front
plate 40, four vanes 70 assembled to the inner rotor 20, and a lock
plate 80 (lock member) (see FIG. 2) assembled to the outer rotor
30.
[0018] The timing sprocket 31 receives the rotation force in the
clockwise direction thereof, which is shown as a rotation direction
of camshaft in FIG. 2. The rotation force is transmitted from a
crankshaft (not shown) via a crank sprocket (not shown) and a
timing chain (not shown).
[0019] The camshaft 10 includes a known cam (not shown) for
opening/closing an exhaust valve (not shown). An advanced angle
fluid passage (fluid pressure circuit) 11 and a retarded angle
fluid passage (fluid pressure circuit) 12 extending in an axial
direction of the camshaft 10 are provided inside of the camshaft
10. The advanced angle fluid passage 11 is connected to a first
connecting port 201 of a switching valve 200 via a passage 71
provided on the camshaft 10 in the radial direction thereof, an
annular groove 14, and a connecting passage 16 provided on the
cylinder head 100. In addition, the retarded angle fluid passage 12
is connected to a second connecting port 202 of the switching valve
200 via a passage 72 provided on the camshaft 10 in the radial
direction thereof, an annular groove 13, and a connecting passage
15 provided on the cylinder head 100.
[0020] The switching valve 200 is a known type in which a spool 204
is moved against a biasing force of a spring (not shown) by
energizing a solenoid 203. When the solenoid 203 is de-energized, a
supply port 206 connected to an oil pump 205 that is driven by the
internal combustion engine communicates with the first connecting
port 201 as shown in FIG. 1. At the same time, the second
connecting port 202 communicates with a discharge port 207. When
the solenoid 203 is energized, the supply port 206 communicates
with the second connecting port 202 and at the same time the first
connecting port 201 communicates with the discharge port 207.
Therefore, in case that the solenoid 203 of the switching valve 200
is de-energized, the operation fluid (fluid pressure) is supplied
to the advanced angle fluid passage 11. In case that the solenoid
203 is energized, the operation fluid is supplied to the retarded
angle fluid passage 12. Energization of the solenoid 203 of the
switching valve 200 is duty-controlled by which a ratio of
energization/de-energization per unit time is changed. For example,
when the switching valve 200 is duty-controlled at 50%, the first
and second ports 201 and 202, and the supply and discharge ports
206 and 207 are not connected to each other.
[0021] The inner rotor 20 is integrally fixed to the camshaft 10
via an installation bolt 91. As shown in FIG. 2, four vane grooves
21 and a receiving hole 22 are formed on the inner rotor 20. In
addition, four first fluid passages 23 (fluid pressure circuit),
three second fluid passages 24 (fluid pressure circuit) extending
in the radial direction of the inner rotor 20, a fluid groove 24a
(fluid pressure circuit), and a lock fluid passage 25 for
connecting a bottom portion 22d of the receiving hole 22 to the
advanced angle fluid passage 11.
[0022] As shown in FIG. 2, the vanes 70 are positioned in the vane
grooves 21 respectively, being movable in the radial direction of
the inner rotor 20. The four vanes 70 are movable within four fluid
pressure chambers R0 respectively, which are each defined between
the outer rotor 30 and the inner rotor 20 and arranged, dividing
each fluid pressure chamber R0 into an advanced angle chamber R1
and a retarded angle chamber R2. Each vane 70 is biased in the
radially outward direction by a vane spring 73 (see FIG. 1)
disposed between the bottom portion of each vane groove 21 and the
bottom face of each vane 70.
[0023] As shown in FIG. 2, the operation fluid (fluid pressure) is
supplied to or discharged from the four advanced angle chambers R1,
which are defined and divided by the vanes 70, via the advanced
angle fluid passage 11 and the first fluid passage 23. In addition,
the operation fluid is supplied to or discharged from three
retarded angle chambers R2 out of four via the retarded angle fluid
passage 12 and the second fluid passage 24. The operation fluid is
supplied to the lock plate 80 from the lock fluid passage 25 formed
on the bottom portion 22d of the receiving hole 22. When the lock
plate 80 is moved, the operation fluid is supplied to or discharged
from the remaining (i.e. one out of four) retarded angle chamber R2
via the fluid groove 24a connecting the lock fluid passage 25 and
that retarded angle chamber R2. Accordingly, for one retarded angle
chamber R2 out of four, the second fluid passage 24 is not provided
and the lock fluid passage 25 is shared to be used, which may
achieve a simple structure of the fluid pressure circuit.
[0024] Both side portions of the outer rotor 30 in the axial
direction thereof are integrally fixed to the annular shaped front
plate 40 and the rear plate 50 respectively via five connecting
bolts 92. The timing sprocket 31 is integrally formed on an outer
periphery of the outer rotor 30 and on an end side in the axial
direction thereof to which the rear plate 50 is connected. In
addition, five convex portions 33 are formed on the inner
circumference of the outer rotor 30 in the circumferential
direction thereof so as to project in the radially inward
direction. Each inner circumferential face of each convex portion
33 is slidably in contact with an outer circumferential face of the
inner rotor 20. That is, the outer rotor 30 is rotatably supported
on the inner rotor 20. A side face 33a (stopper) of one convex
portion 33A out of the five convex portions 33 is in contact with a
side face 70a of a vane 70A, thereby defining a relative rotational
angle between the outer rotor 30 and the inner rotor 20 to the
advanced angle side. In addition, a side face 33b (stopper) of one
convex portion 33B is in contact with a side face 70b of a vane
70B, thereby defining the relative rotational angle between the
outer rotor 30 and the inner rotor 20 to the retarded angle side. A
retracting groove portion 34 for accommodating the lock plate 80,
and a receiving bore 35 connected to the retracting groove portion
34 for accommodating a coil spring 81 that biases the lock plate 80
in the radially inward direction of the outer rotor 30 are formed
between the two convex portions 33 out of five. The four fluid
pressure chambers R0 mentioned above are formed between five convex
portions 33, respectively.
[0025] As shown in FIG. 3, a head portion 80a of the lock plate 80,
i.e. facing the bottom portion 22d of the receiving hole 22, has a
trapezoidal shape in cross section formed by a convex taper portion
extending in the radially inward direction of the outer rotor 30
and a top portion. An inner peripheral face 22b is formed by a
concave taper portion 22c having a trapezoidal shape in cross
section and gradually expanding towards an opening portion 22a, and
the bottom portion 22d. When the relative rotation between the
inner rotor 20 and the outer rotor 30 is restricted, the lock plate
80 is positioned in the receiving hole 22. An end portion 80b
(contact portion) of the top portion of the lock plate 80 is in
contact with the inner peripheral face 22b of the receiving hole 22
on the advanced angle side and the retarded angle side between the
opening portion 22a and the bottom portion 22d of the receiving
hole 22. In addition, a contact width B in the circumferential
direction of the contact portion 80b of the lock plate 80, with
which the inner peripheral face 22b of the receiving hole 22 on the
advanced angle side and the retarded angle side is in contact, is
larger than a bottom width D in the circumferential direction of
the bottom portion 22d of the receiving hole 22. Therefore, when
the lock plate 80 is positioned in the receiving hole 22, the end
portion 80b of the lock plate 80 and the taper portion 22c of the
inner peripheral face 22b of the receiving hole 22 are in contact
with each other on the advanced angle side and the retarded angle
side, thereby restricting the relative rotation between the inner
rotor 20 and the outer rotor 30. As a result, the occurrence of the
hitting sound by the contact between the end portion 80b and the
taper portion 22c due to the fluctuation torque of the cam may be
prevented. The head portion 80a of the lock plate 80 may have a
substantially rectangular shape instead of the trapezoidal shape.
The end portion 80b of the lock plate 80 may be chamfered.
[0026] When the relative rotation between the inner rotor 20 and
the outer rotor 30 is restricted, the lock plate 80 is positioned
in the receiving hole 22. At the same time, a gap C is formed
between the side face 33a of the convex portion 33A and the side
face 70a of the vane 70A. Therefore, when the fluctuation torque by
the camshaft 10 is applied to the end portion 80b and the taper
portion 22c in the advanced angle direction and the retarded angle
direction alternately under the condition that the operation fluid
is supplied to the receiving hole 22 and thus the relative rotation
between the inner rotor 20 and the outer rotor 30 is permitted,
i.e. the locked state thereof is released, the lock plate 80 and
the receiving hole 22 are prevented from being strongly constrained
each other. Then, the lock plate 80 and the receiving hole 22
rotate relative to each other, which brings the end portion 80b of
the lock plate 80 to be pushed by the taper portion 22c of the
inner peripheral face 22b of the receiving hole 22. The lock plate
80 is thus biased to move from the receiving hole 22, thereby
causing the locked state of the relative rotation between the inner
rotor 20 and the outer rotor 30 to be easily released.
[0027] A size of the gap C is defined such that when the side face
70a of the vane 70A is in contact with the side face 33a of the
convex portion 33A to thereby restrict the relative rotation
between the inner rotor 20 and the outer rotor 30 at the most
advanced angle phase, the head portion 80a of the lock plate 80 is
guided in radially inward direction of the receiving hole 22 with
being in contact with the inner peripheral face 22b of the
receiving hole 22. That is, when the relative rotation between the
inner rotor 20 and the outer rotor 30 is restricted at the most
advanced angle phase by the side face 70a of the vane 70A being in
contact with the side face 33a of the convex portion 33A, the head
portion 80a of the lock plate 80 is guided in the radially inward
direction of the receiving hole 22. Then, when the vane 70 is
separated from the convex portion 33 due to the fluctuation torque
of the cam, the head portion 80a of the lock plate 80 is further
inserted into the radially inward direction of the receiving hole
22. The end portion 80b of the lock plate 80 and the taper portion
22c of the inner peripheral face 22b of the receiving hole 22 are
in contact with each other on the advanced angle side and the
retarded angle side, thereby restricting the relative rotation
between the inner rotor 20 and the outer rotor 30.
[0028] The torsion spring 60 is provided by engaging with the front
plate 40 at one end and the inner rotor 20 at the other end. The
torsion spring 60 biases the inner rotor 20 towards the advanced
angle side (clockwise direction in FIG. 2) relative to the outer
rotor 30, the front plate 40 and the rear plate 50. Thus, the
operation response of the inner rotor 20 to the advanced angle side
may be improved.
[0029] According to the above-mentioned embodiment, when the
internal combustion engine is stopped, the oil pump 205 is stopped
and also the switching valve 200 is not energized. Thus, the
operation fluid is not supplied to the fluid pressure chambers R0.
At this time, the head portion 80a of the lock plate 80 is
positioned within the receiving hole 22 of the inner rotor 20 and
thus the relative rotation between the inner rotor 20 and the outer
rotor 30 is restricted. Even when the internal combustion engine is
started and the oil pump 205 is driven, the operation fluid
supplied from the oil pump 205 is only virtually provided to the
advanced angle chamber R1 via the connecting passage 16, the
advanced angle fluid passage 11, and the first fluid passage 23
while the duty ratio is small for energizing the switching valve
200 (i.e. the ratio of energizing time relative to the
de-energizing time per unit time is small). Therefore, the variable
valve timing control device 1 is maintained in a locked state.
[0030] When the retarded angle phase is required for the valve
timing depending on the operation condition of the internal
combustion engine, the duty ratio for energizing the switching
valve 200 is brought to be large and then the position of the spool
204 is switched. The operation fluid supplied from the oil pump 205
is provided to the retarded angle chamber R2 by passing through the
connecting passage 15, the retarded angle fluid passage 12, and the
second fluid passage 24, or by passing through the fluid groove 24a
after supplied to the receiving hole 22 from the lock fluid passage
25.
[0031] Meanwhile, the operation fluid stored in the advanced angle
chamber R1 is sent to the first fluid passage 23, the advanced
angle fluid passage 11, and the connecting passage 16 to be
discharged from the discharge port 207 of the switching valve 200.
Therefore, the lock plate 80 is moved against the biasing force of
the spring 81, thereby moving the head portion 80a from the
receiving hole 22. Then, the locked state between the inner rotor
20 and the outer rotor 30 is released. At the same time, the inner
rotor 20 integrally rotating with the camshaft 10 and each vane 70
rotate relative to the outer rotor 30, the front plate 40, and the
rear plate 50 in the retarded angle direction (counterclockwise
direction in FIG. 2). Due to the aforementioned relative rotation,
the timing of the cam is brought in the advanced angle state. The
relative rotation phase may be defined arbitrarily by controlling
the duty ratio of the switching valve 200. For example, the
relative rotation between the inner rotor 20 and the outer rotor 30
may be stopped at the intermediate phase.
[0032] According to the aforementioned embodiment, the lock plate
80 is in contact with the inner peripheral face 22b of the
receiving hole 22 on the advanced angle side and the retarded angle
side between the opening portion 22a and the bottom portion 22d of
the receiving hole 22 when the relative rotation between the rotor
member 2 and the housing member 3 is restricted. Thus, the lock
plate 80 and the receiving hole 22 are in contact with each other
to thereby restrict the relative rotation between the rotor member
2 and the housing member 3 to the advanced angle side and the
retarded angle side. The occurrence of the hitting sound due to the
contact between the lock plate 80 and the receiving hole 22 may be
prevented accordingly.
[0033] In addition, according to the aforementioned embodiment,
when the relative rotation is restricted, the lock plate 80 and the
receiving hole 22 are in contact with each other since the contact
width B in the circumferential direction of the contact portion 80b
of the lock plate 80, with which the inner peripheral face 22b of
the receiving hole 22 on the advanced angle side and the retarded
angle side is in contact, is larger than the bottom width D in the
circumferential direction of the bottom portion 22d of the
receiving hole 22, thereby avoiding the occurrence of the hitting
sound.
[0034] Further, according to the aforementioned embodiment, when
the relative rotation is restricted, the lock plate 80 and the
receiving hole 22 are prevented from being strongly constrained
each other under the condition that the fluctuation torque by the
camshaft 10 is applied to the contact portion 80b and the inner
peripheral face 22b in the advanced angle direction and the
retarded angle direction alternately since the gap C is formed
between the side face 33a of the convex portion 33A and the side
face 70a of the vane 70A. Thus, the lock plate 80 is moved from the
receiving hole 22 by the operation fluid that is produced when the
locked state of the relative rotation is released.
[0035] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the sprit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *