Information
-
Patent Grant
-
6779500
-
Patent Number
6,779,500
-
Date Filed
Monday, June 24, 200222 years ago
-
Date Issued
Tuesday, August 24, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Corrigan; Jaime
Agents
- Burns, Doane, Swecker & Mathis, L.L.P.
-
CPC
-
US Classifications
Field of Search
US
- 123 9012
- 123 9015
- 123 9016
- 123 9017
- 464 1
- 464 2
- 464 160
- 464 9031
- 074 568 R
-
International Classifications
-
Abstract
A variable valve timing control apparatus includes a relative rotation control mechanism and a fluid pressure passage. The relative rotation control mechanism restrains a relative rotation between a rotor and a housing at an intermediate phase position between the most advanced angle phase position and the most retarded angle phase position. The fluid pressure passage includes a first fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom and a second fluid path for supplying the fluid to an advance angle chamber and a retard angle chamber and for draining the fluid therefrom. The first fluid path is defined independently of the second fluid path.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority under 35 U.S.C. ยง 119 with respect to a Japanese Patent Application 2001-197372, filed on Jun. 28, 2001, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
This invention generally relates to a variable valve timing control apparatus for controlling an opening/closing timing of a valve of an internal combustion engine.
BACKGROUND OF THE INVENTION
A Japanese Patent Laid-open Application No. 2001-41012 discloses a variable valve timing control apparatus which is provided with a housing, a vane body, an oil pressure control device, and an intermediate position lock pin. The housing is connected to one of a cam shaft of an internal combustion engine and a crank shaft thereof and includes walls radially formed at an interior of the housing. The walls define the interior of the housing into spaces. The vane body is connected to the other one of the cam shaft and the crank shaft and is rotatably disposed in the interior of the housing. The vane body is provided with radially formed vanes for defining each defined space into an advance angle chamber and a retard angle chamber. The oil pressure control device controls an oil pressure to be supplied to the advance angle chamber and the retard angle chamber so as to rotate the vane body relative to the housing. A relative rotational phase between the crank shaft and the cam shaft can be hence varied in response to the rotation of the vane body relative to the housing. The intermediate position lock pin is equipped to the vane body and is projected from the vane body so as to be engaged with an engaging bore defined in the housing when a pressure level in the chambers is lower than a predetermined pressure level. The vane body is then locked by the intermediate position lock pin at an intermediate position between the most advanced angle phase position of the vane body relative to the housing and the most retarded angle phase position thereof relative to the housing.
However, according to the above described variable valve timing control apparatus, the oil for releasing the intermediate position lock pin from the engaging bore is supplied to a pressure receiving surface of the intermediate position lock pin either from the advance angle chamber via a hydraulic passage or from the retard angle chamber via the other hydraulic passage. Accordingly, when restarting the internal combustion engine immediately after being stopped, the intermediate position lock pin may be engaged with the engaging bore so as to maintain the vane body at the intermediate position under the state where the advance angle chamber (or the retard angle chamber) has been filled with the oil. When the vane body is rotated due to a variable torque applied from the cam shaft under the above condition, the volume of the advance angle chamber (or the retard angle chamber) is varied. When the volume of the advance angle chamber (or the retard angle chamber) is decreased, the oil pressure level in the advance angle chamber (or the retard angle chamber) is temporarily increased. On the other hand, when the volume thereof is increased, the oil pressure level therein is returned down to the former oil pressure level. The variation of the oil pressure level acts on the pressure receiving surface of the intermediate position lock pin from the advance angle chamber (or from the retard angle chamber) via the hydraulic passage. Therefore, an operation of the intermediate position lock pin to be engaged with the engaging bore and to be disengaged therefrom is repeatedly performed.
As a result of this, when the variable torque is applied to the vane body before the intermediate position lock pin, which has been disengaged from the engaging bore, is engaged with the engaging bore, the vane body may be rotated relative to the housing. In other words, the phase of the vane body relative to the housing can not be maintained at the intermediate position by the intermediate position lock pin.
Accordingly, the above disclosed variable valve timing control apparatus is still susceptible of certain improvements with respect to assuring the engagement of the intermediate position lock pin with the engaging bore of the housing even when the oil pressure level variation occurs in the advance angle chamber (or the retard angle chamber) due to the variable torque from the cam shaft.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, a variable valve timing control apparatus includes a housing integrally rotated with one of a crank shaft of an internal combustion engine and a cam shaft thereof, a rotor provided in the housing and integrally rotated with the other one of the crank shaft and the cam shaft, a hydraulic chamber defined between the housing and the rotor, a vane assembled in the rotor for dividing the hydraulic chamber into an advance angle chamber and a retard angle chamber, a relative rotation control mechanism for restraining a relative rotation between the rotor and the housing at an intermediate phase position between the most advanced angle phase position and the most retarded angle phase position in response to a fluid supplied to the relative rotation control mechanism and a fluid drained therefrom, and a fluid pressure passage for controlling the fluid supplied to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for controlling the fluid drained therefrom Further, the fluid pressure passage includes a first fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a second fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom.
Therefore, the fluid supplied to the relative rotation control mechanism and drained therefrom can be controlled regardless of the fluid supplied to the advance angle chamber or the retard angle chamber and drained therefrom.
According to a second aspect of the present invention, the fluid pressure passage further includes a hydraulic pressure control valve for supplying the fluid to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for draining the fluid therefrom. The hydraulic pressure control valve includes a third fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a fourth fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom.
Therefore, the fluid can be supplied to and/or drained from the relative rotation control mechanism independently of the fluid supplied to and/or drained from the advance angle chamber and the retard angle chamber.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
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 drawing figures wherein:
FIG. 1
illustrates an entire structure of a variable valve timing control apparatus according to a first embodiment of the present invention;
FIG. 2
is a cross-sectional view of the variable valve timing control apparatus illustrated in
FIG. 1
;
FIG. 3
is a cross-sectional view of the variable valve timing control apparatus under the most advanced angle condition according to the present invention;
FIG. 4
is a cross-sectional view of the variable valve timing control apparatus under the most retarded angle condition according to the present invention;
FIG. 5
is an enlarged view illustrating a first excited condition of a hydraulic pressure control valve according to the first embodiment of the present invention;
FIG. 6
is an enlarged view illustrating a second excited condition of the hydraulic pressure control valve according to the first embodiment of the present invention;
FIG. 7
is an enlarged view illustrating a third excited condition of the hydraulic pressure control valve according to the first embodiment of the present invention;
FIG. 8
is an enlarged view illustrating a fourth excited condition of the hydraulic pressure control valve according to the first embodiment of the present invention;
FIG. 9
illustrates an entire structure of the variable valve timing control apparatus according to a second embodiment of the present invention;
FIG. 10
is an enlarged view illustrating a first excited condition of a hydraulic pressure control valve according to the second embodiment of the present invention;
FIG. 11
is an enlarged view illustrating a second excited condition of the hydraulic pressure control valve according to the second embodiment of the present invention;
FIG. 12
is an enlarged view illustrating a third condition of the hydraulic pressure control valve according to the second embodiment of the present invention;
FIG. 13
is an enlarged view illustrating a fourth condition of the hydraulic pressure control valve according to the second embodiment of the present invention; and
FIG. 14
is an enlarged view illustrating a fifth condition of the hydraulic pressure control valve according to the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a variable valve timing control apparatus according to a first embodiment of the present invention is described with reference to drawings. Hatching lines in
FIG. 2
are omitted for simplifying the drawing.
The variable valve timing control apparatus according to the first embodiment of the present invention illustrated in
FIGS. 1
,
2
is mainly provided with a rotor
21
, a connector
40
, a housing
30
, a transmitting member
90
, a first control mechanism B
1
, a second control mechanism B
2
, and a hydraulic pressure control valve
100
. The rotor
21
and the connector
40
are integrally assembled to a tip end portion of a cam shaft (a driven shaft)
10
by means of a volt (not shown). The connector
40
is disposed between each opposing end surface of the cam shaft
10
and the rotor
21
so as to connect the cam shaft
10
and the rotor
21
. The rotor
21
is screwed integrally with a tip end of the connector
40
. The housing
30
is disposed at an outer side of the rotor
21
to be rotated relative to the rotor
21
. The rotational force of a crank shaft (a rotational shaft)
2
of an internal combustion engine (hereinafter, referred to as an engine)
1
is transmitted to the housing
30
via the transmitting member
90
. According to the first embodiment of the present invention, a timing chain is applied to the transmitting member
90
. Each first and second control mechanism B
1
, B
2
serves as a relative rotation control mechanism for controlling a rotation of the rotor
21
relative to the housing
30
. The hydraulic pressure control valve
100
controls oil (fluid) to be supplied to an advance angle chamber R
1
, a retard angle chamber R
2
and to be drained therefrom. The hydraulic pressure control valve
100
further controls the oil (the fluid) to be supplied to the first, second control mechanisms B
1
, B
2
and to be drained therefrom. The fluid is supplied to the advance angle chamber R
1
, the retard angle chamber R
2
, the first, second control mechanisms B
1
, B
2
, via a fluid pressure passage. The advance angle chamber R
1
and the retard angle chamber R
2
are described later.
The cam shaft
10
is equipped with a known cam (not shown) for performing an opening/closing operation of an intake valve (not shown) or an exhaust valve (not shown). The cam shaft
10
is rotatably supported by a cylinder head (not shown) of the engine
1
. An advance oil path
11
and four retard oil paths
12
extend in the cam shaft
10
in an axial direction thereof. The advance oil path
11
is connected to an advance port
102
of the hydraulic pressure control valve
100
via a radial oil bore
13
and an annular oil path
14
. Each retard oil path
12
is connected to a retard port
101
of the hydraulic pressure control valve
100
via a radial oil bore
15
and an annular oil path
16
. Further, the cam shaft
10
is provided with axial oil paths
17
a
,
17
b
(
17
b
is not shown), radial oil bores
18
a
,
18
b
(
18
b
is not shown), and an annular oil path
19
therein. The oil paths
17
a
,
17
b
are defined in the cam shaft
10
independently of the advance oil path
11
and the retard oil path
12
. As described later, the oil path
17
a
, the oil bore
18
a
, and the oil path
19
forms an oil path (a first fluid path of the fluid pressure passage) for supplying the oil to the first control mechanism B
1
. On the other hand, the oil path
17
b
, the oil bore
18
b
, and the oil path
19
forms an oil path (the first fluid path) for supplying the oil to the second control mechanism B
2
. The axial oil paths
17
a
,
17
b
communicate with the oil path
19
via the radial oil bores
18
a
,
18
b
, respectively. The annular oil path
19
is connected with a lock port
108
of the hydraulic pressure control valve
100
.
An axial oil path
41
is defined in the connector
40
and communicates with the advance oil path
11
. Four axial oil paths
42
are further defined in the connector
40
and communicate with four retard oil paths
12
, respectively. Further, the other axial oil paths
43
a
,
43
b
(
43
b
is not shown) are defined in the connector,
40
and communicate with the axial oil paths
17
a
,
17
b
, respectively. The rotor
21
includes a central inner bore
21
b
of which front end is closed by a head portion of a not-shown bolt. The central inner bore
21
b
communicates with the advance oil path
11
via the axial oil path
41
in the connector
40
.
As illustrated in
FIG. 2
, the rotor
21
is provided with a vane groove
21
a
for assembling four vanes
23
and four springs
24
(as illustrated in
FIG. 1
) for biasing the vanes
23
in a radial direction of the rotor
21
: The vanes
23
assembled in the vane groove
21
a
extend outwardly in the radial direction of the rotor
21
and define the four advance angle chambers R
1
and the four retard chambers R
2
in the housing
30
. The rotor
21
is further provided with oil bores
21
c
,
21
d
,
21
e
. The oil bores
21
c
communicate with the retard oil paths
12
via the oil paths
42
axially defined in the connector
40
. The oil bore
21
d
communicates with the oil path
17
a
axially defined in the cam shaft
10
via the oil path
43
a
axially defined in the connector
40
. The oil bore
21
e
communicates with the oil path
17
b
axially defined in the cam shaft
10
via the oil path
43
b
(not shown) axially defined in the connector
40
. The rotor
21
is further provided with four radial oil bores
21
f
and four radial oil bores
21
g
. The oil bores
21
f
communicate with the central inner bore
21
b
at an inner end in the radial direction of the rotor
21
and further communicate with the advance angle chamber R
1
at an outer end in the radial direction thereof. The oil bores
21
g
communicate with the oil bores
21
c
at the inner end in the radial direction of the rotor
21
and further communicate with the retard angle chamber R
2
at the outer end in the radial direction thereof. The rotor
21
is still further provided with radial oil bores
21
h
,
21
j
. The oil bore
21
h
communicates with the oil bore
21
d
at the inner end in the radial direction of the rotor
21
and further communicates with a lock groove
21
k
of the first control mechanism B
1
at the outer end in the radial direction thereof. The oil hole
21
j
communicates with the oil hole
21
e
at the inner end in the radial direction of the rotor
21
and further communicates with a lock groove
21
l
of the second control mechanism B
2
at the outer end in the radial direction thereof.
The housing
30
is formed of a housing body
31
, a front plate
32
, a rear thin plate
33
which all are integrally connected by means of a bolt
34
. A sprocket
31
a
is integrally formed at a rear outer periphery of the housing body
31
. As being known, the sprocket
31
a
is operatively connected to the crank shaft
2
of the engine
1
via the transmitting member
90
, i.e. the timing chain
90
. The sprocket
31
a
is operatively rotated in a counterclockwise direction in
FIG. 2
corresponding to the driving force transmitted from the crank shaft
2
. The housing body
31
is provided with four projecting portions
31
b
projecting toward the center in the radial direction of the housing body
31
, whereby hydraulic chambers
31
c
are defined between each projecting portion
31
b
, respectively. A vane
23
is disposed in each hydraulic chamber
31
c
for defining the advance angle chamber R
1
and the retard angle chamber R
2
. Axial end surfaces of the front plate
32
and the rear thin plate
33
, which oppose to each other, are slidably in contact with axial end surfaces of the rotor
21
and axial end surfaces of the vanes
23
, respectively. As illustrated in
FIG. 2
, one of the hydraulic chambers
31
c
includes a projection
31
d
(a first projection) for defining the most advanced angle phase position when the vane
23
comes in contact with the projection
31
d
and a projection
31
e
(a second projection) for defining the most retarded angle phase position when the vane
23
comes in contact with the projection
31
e.
The first control mechanism B
1
is unlocked when the oil is supplied thereto from the lock port
108
of the hydraulic pressure control valve
100
via the oil path
19
, the oil bore
18
a
, the oil paths
17
a
,
43
a
, and the oil bores
21
d
,
21
h
. The second control mechanism B
2
is unlocked when the oil is supplied thereto from the lock port
108
via the oil path
19
, the oil bore
18
b
, the oil paths
17
b
,
43
b
, and the oil bores
21
e
,
21
j
. Accordingly, the rotation of the rotor
21
relative to the housing
30
can be allowed. In the meantime, as illustrated in
FIG. 2
, the first, second control mechanisms B
1
, B
2
are locked when the oil is drained to the oil paths
17
a
,
17
b
, respectively. Therefore, the rotation of the rotor
21
relative to the housing
30
in an advance angle direction is restrained at the intermediate phase position between the most retarded angle phase position and the most advanced angle phase position. As described above, according to the first embodiment of the present invention, the first fluid path for supplying the fluid to the first, second control mechanisms B
1
, B
2
and for draining the fluid therefrom are formed of the oil path
19
, the oil bores
18
a
,
18
b
, the oil paths
17
a
,
17
b
,
43
a
,
43
b
, and the oil bores
21
d
,
21
e
,
21
h
,
21
j.
The first control mechanism B
1
is further provided with a lock plate
61
, a lock spring
62
and the second control mechanism B
2
is further provided with a lock plate
63
, a lock spring
64
. Each lock plate
61
,
63
is assembled in each evacuation bore
31
f
radially defined in the housing body
31
so as to be slidably movable in the radial direction of the housing body
31
. Each lock spring
62
,
64
is accommodated in each accommodating portion
31
g
. Therefore, each lock plate
61
,
63
is biased by each lock spring
62
,
64
to be projected from each evacuation bore
31
f
. Each tip end portion of each lock plate
61
,
63
can be slidably inserted into each lock groove
21
k
,
21
l
or evacuated therefrom. Therefore, the lock plates
61
,
63
are moved in the radial direction against the biasing fore of the lock springs
62
,
64
when the oil is supplied to the lock grooves
21
k
,
21
l
so as to be evacuated into the evacuation hole
31
f
. The tip ends of the lock plates
61
,
63
can become in contact with the peripheral surface of the rotor
21
. In this case, the rotor
21
can be rotated. Further, as illustrated in
FIG. 2
, tip ends at inner sides in the radial direction of the lock grooves
21
k
,
21
l
is matched with the evacuation holes
31
f
when the rotor
21
is at the intermediate phase position relative to the housing
30
.
A torsion spring is disposed between the housing
30
and the rotor
21
for biasing the rotor
21
to be rotated in the advance angle direction relative to the housing
30
. Therefore, the rotor
21
can be rotated in the advance angle direction relative to the housing
30
with a good response.
The hydraulic pressure control valve
100
illustrated in
FIG. 1
forms an oil pressure circuit C having an oil pump
110
driven by the engine
1
, an oil pan
120
thereof. Further, the hydraulic pressure control valve
100
is a variable electromagnetic spool valve for moving a spool
104
against a spring
105
in response to electric current supplied to a solenoid
103
by an electronic control unit (ECU). The ECU controls a duty value (%) of the electric current to be supplied to the solenoid
103
so as to change the stroke amount of a pushing member
130
for pushing the spool
104
. The position of the spool
104
disposed in a sleeve
150
(as illustrated in
FIG. 2
) is hence changed resulting from the duty value control. Therefore, the oil supply to the advance oil path
11
, the retard oil path
12
, the first, second control mechanisms B
1
, B
2
and the oil drain therefrom can be controlled. The oil pressure circuit C is formed of an oil path S
1
connecting the oil pan
120
and the oil pump
110
, an oil path S
21
connecting an outlet port (not shown) of the oil pump
110
and a first supply port
106
a
(described later) of the hydraulic pressure control valve
100
, an oil path S
22
for connecting the outlet port of the oil pump
110
and a second supply port
106
b
(described later) of the hydraulic pressure control valve
100
, and an oil path D connecting a drain port
107
and the oil pan
120
. In this case, the fluid can be drained from the advance angle chamber R
1
and the retard angle chamber R
2
to the oil pan
120
via the drain port
107
, the oil path D. Therefore, the fluid in each chamber R
1
and R
2
is not applied as a resistance against a rotation of the vane
23
in each chamber R
1
and R
2
.
The oil pump
110
driven by the engine
1
supplies the oil from the oil pan
120
to the supply ports
106
a
,
106
b
. The oil can be circulated from the drain port
107
to the oil pan
120
. The ECU receives signals detected by various sensors including a crank angle, a cam angle, a throttle opening degree, an internal combustion engine rotational number, an internal combustion engine cooling water temperature, a vehicle speed. An output from the ECU, i.e. the duty value of the electric current supplied to the solenoid
103
, can be controlled employing a predetermined control routine based upon the detected signals in response to the internal combustion engine driving condition.
As being enlarged in
FIG. 5
, the spool
104
of the hydraulic pressure control valve
100
is provided with six land portions
104
a
,
104
b
,
104
c
,
104
d
,
104
e
,
104
f
, five annular grooves
104
g
,
104
h
,
104
j
,
104
k
,
104
l
, three annular grooves
150
a
,
150
b
,
150
c
, and connecting ports
104
m
,
104
n
,
104
p
. Each annular groove
104
g
,
104
h
,
104
j
,
104
k
,
104
l
is defined between each land portion. Each annular groove
150
a
,
150
b
,
150
c
is defined in the spool
150
. Each connecting port
104
m
,
104
n
,
104
p
is defined for connecting each annular groove
104
g
,
104
j
,
104
l
and the drain port
107
. A lap amount L1 between the annular groove
104
g
and the annular groove
150
a
is set to be equal to or smaller than a lap amount L2 between the annular groove
150
a
and the annular groove
104
h
. The lap amount L2 is set to be smaller than a lap amount L3 between the annular groove
104
j
and the annular groove
150
b
. The lap amount L3 is set to be equal to or smaller than a lap amount L4 between the annular groove
104
k
and the annular groove
150
c
. The lap amount L4 is set to be smaller than a lap amount L5 between the annular groove
150
b
and the annular groove
104
k
. The lap amount L5 is set to be equal to or smaller than a lap amount L6 between the annular groove
150
c
and the annular groove
104
l
. The fluid pressure passage further includes an oil path (a third fluid path) connected to the relative rotation control valve and an oil path (a fourth fluid path) connected to the advance angle chamber and the retard angle chamber in response to the position of the spool
104
.
When the spool
104
is positioned as illustrated in
FIG. 5
, i.e. when the solenoid
103
is under a excited condition with the duty ratio of 0%, the communication between the first supply port
106
a
and the lock port
108
is interrupted by the land portion
104
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
104
d
, and yet the communication between the second supply port
106
b
and the advance port
102
is established by the land portion
104
e
. The lock port
108
can be allowed to communicate with the drain port
107
via the annular groove
104
g
and the connecting port
104
m
by means of the land portion
104
b
. The retard port
101
can be also allowed to communicate with the drain port
107
via the annular groove
104
j
and the connecting port
104
n
by means of the land portion
104
d
. Therefore, the oil can be drained from the retard port
101
, the lock port
108
, the lock groove
21
k
of the first control mechanism B
1
, the lock groove
21
l
of the second control mechanism B
2
, and the retard angle chamber R
2
. On the other hand, the advance angle chamber R
1
can be supplied with the oil.
When the spool
104
is positioned as illustrated in
FIG. 6
, the communication between the first supply port
106
a
and the lock port
108
can be established by the land portion
104
b
. The communication between the lock port
108
and the drain port
107
is interrupted by the land portion
104
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
104
d
. The communication between the second supply port
106
b
and the advance port
102
can be established by the land portion
104
e
. The retard port
101
is allowed to communicate with the drain port
107
via the annular groove
104
j
and the connecting port
104
n
by means of the land portion
104
d
. Therefore, the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
and the advance angle chamber R
1
can be supplied with the oil. On the other hand, the oil can be drained from the retard angle chamber R
2
.
When the spool
104
is positioned as illustrated in
FIG. 7
, the communication between the first supply port
106
a
and the lock port
108
can be established by the land portion
104
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
104
d
. The communication between the second supply port
106
b
and the advance port
102
is also interrupted by the land portion
104
e
. The communication between the retard port
101
and the drain port
107
is interrupted by the land portion
104
d
and the communication between the advance port
102
and the drain port
107
is interrupted by the land portion
104
e
. Therefore, the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
can be supplied with the oil. The supply of the oil to the chambers R
1
, R
2
and the drain of the oil therefrom are interrupted.
When the spool
104
is positioned as illustrated in
FIG. 8
, the first supply port
106
a
can be allowed to connect with the lock port
108
via the annular groove
104
h
by means of the land portion
104
c
. The second supply port
106
b
can be allowed to communicate with the retard port
101
via the annular groove
104
k
by means of the land portion
104
d
. The communication between the second supply port
106
b
and the advance port
102
is interrupted by the land portion
104
e
. The advance port
102
can be allowed to communicate with the drain port
107
via the annular groove
104
l
and the connecting port
104
p
by means of the land portion
104
e
. Therefore, the oil can be supplied to the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
and the retard angle chamber R
2
. On the other hand, the oil can be drained from the advance angle chamber R
1
.
The above described hydraulic pressure control valve
100
according to the first embodiment of the present invention includes the ECU for controlling the exciting operation of the solenoid
103
based upon the predetermined control routine.
When starting the engine
1
that has been stopped, the electric current has not been supplied to the solenoid
103
of the hydraulic pressure control valve
100
by the ECU. Therefore, the spool
104
is maintained as illustrated in FIG.
5
. The oil discharged from the oil pump
110
can be, supplied to the advance angle chamber R
1
via the oil pressure circuit C. At, the same time, the oil can be drained from the first, second control mechanisms B
1
, B
2
, and the retard angle chamber R
2
to the oil pan
120
via the oil pressure circuit C. Therefore, the advance angle chamber R
1
is gradually filled with the oil. At the meantime, the first and second control mechanisms B
1
, B
2
, from which the oil has been drained, are operated to be locked. More specifically, when initially starting the engine
1
, the rotor
21
is rotated in a retard direction relative to the housing
30
due to the variable torque applied from the cam shaft
10
. Accordingly, when the phase of the rotor
21
relative to the housing
30
is positioned at the advance side relative to the intermediate phase position with the engine
1
being stopped, the rotor
21
is gradually rotated in the retard direction due to the variable torque so as to reach the intermediate phase position. The lock plates
61
,
63
are opposed to the lock grooves
21
k
,
21
l
and are then inserted thereinto. Therefore, the rotation of the rotor
21
relative to the housing
30
can be restrained by the lock operation of the first, second control mechanisms B
1
, B
2
.
On the other hand, when the phase of the rotor
21
relative to the housing
30
is positioned at the retard side relative to the intermediate phase position, the rotor
21
is rotated in the advance angle direction corresponding to the oil filled into the advance angle chamber R
1
so as to reach the intermediate phase position. The lock plates
61
,
63
are opposed to the lock grooves
21
k
,
21
l
and are then inserted thereinto. Therefore, the rotation of the rotor
21
relative to the housing
30
can be restrained by the lock operation of the first, second control mechanisms B
1
, B
2
.
As described above, the phase of the rotor
21
relative to the housing
30
can be maintained at the intermediate phase position by firmly performing the lock operation of the first, second control mechanisms B
1
, B
2
.
When the rotor
21
is maintained at the intermediate phase position relative to the housing
30
by the lock operation of the first, second control mechanisms B
1
, B
2
, the vanes
23
can be rotated in response to the rotation of the rotor
21
due to the variable torque applied from the cam shaft
10
. In this case, the volume of the advance angle chamber R
1
filled with the oil (or being filled with the oil) is varied (especially decreased) by the rotated vanes
23
so as to vary (especially increase) the oil pressure level. The first fluid path for operating the first, second control mechanisms B
1
, B
2
are defined, independently of an oil path (a second fluid path of the fluid pressure passage) for supplying the oil to the advance angle chamber R
1
and for draining the oil therefrom. The variation of the oil pressure is hence not acted on the lock grooves
21
k
,
21
l
. Therefore, even when the oil is supplied to the advance angle chamber R
1
when starting the engine
1
, the lock plates
61
,
63
can be prevented from being released due to the variable torque or can be prevented from being maintained under the released condition.
Therefore, according to the variable valve timing control apparatus of the first embodiment of the present invention, the phase of the rotor
21
relative to the housing
30
can be surely maintained at the intermediate phase position. Further, when starting the engine
1
, the first, second control mechanisms B
1
, B
2
can be prevented from being unlocked and the rotor
21
can be prevented from being rotated due to the variable torque applied from the cam shaft
10
. Therefore, the noise caused due to the contact of the vanes
23
with the projections
31
d
,
31
e
can be avoided. Further, the phase of the cam shaft
10
relative to the crank shaft
2
can be maintained at a predetermined phase without being affected by the variation of the phase of the rotor
21
relative to the housing
30
. Therefore, the starting performance of the engine
1
can be prevented from being degraded.
As described above, the electric current supplied to the solenoid
103
can be controlled by the ECU based upon the predetermined control routine. Therefore, according to the first embodiment of the present invention, when the engine
1
is normally activated, the rotational phase of the rotor
21
relative to the housing
30
can be hence adjusted at a predetermined phase within a range between the most retarded angle phase, in which the volume of the advance angle chamber R
1
is set at the minimum level and the volume of the retard angle chamber R
2
at the maximum level as illustrated in
FIG. 4
, and the most advanced angle phase position, in which the volume of the retard angle chamber R
2
is set at the minimum level and the volume of the advance angle chamber R
1
at the maximum level as illustrated in FIG.
3
. Therefore, when the engine
1
is activated, the valve opening/closing timing of the intake valve and the exhaust valve can be adjusted between the opening/closing operation under the most retarded angle condition and the opening/closing operation under the most advanced angle condition, when needed. When the rotor
21
is rotated in the advance angle direction, the hydraulic pressure control valve
100
is adjusted to be set as illustrated in
FIG. 6
by supplying the solenoid
103
with the electric current having the duty ratio controlled by the ECU. When the rotor
21
is rotated in the retard direction, the hydraulic pressure control valve
100
is adjusted to be set as illustrated in
FIG. 8
by supplying the solenoid
103
with the electric current having the duty ratio controlled by the ECU.
The hydraulic pressure control valve
100
is structured for supplying the oil to the first, second control mechanisms B
1
, B
2
when the oil is supplied to one of the advance angle chamber R
1
and the retard angle chamber R
2
. Therefore, the first, second control mechanisms B
1
, B
2
are quickly unlocked when the rotor
21
is rotated in the advance angle direction or in the, retard direction, wherein the rotation of the rotor
21
relative to the housing
30
can be allowed. That is, the smooth operation of the variable valve timing control apparatus according to the first embodiment of the present invention can be assured without preventing the rotor
21
from being rotated.
Alternatively, the oil can be alternately supplied to the chambers R
1
and R
2
by alternately reciprocating the conditions of the hydraulic pressure control valve
100
illustrated in
FIGS. 6
,
8
. Therefore, the oil can be supplied to both chambers R
1
, R
2
. In this case, the phase of the rotor
21
relative to the housing
30
can be smoothly shifted from the condition (a first condition) to be maintained at the intermediate phase position by the first, second control mechanisms B
1
, B
2
to the other condition (a second condition) to be maintained at the intermediate phase position by the oil filled in the chambers R
1
, R
2
.
Hereinafter, the variable valve timing control apparatus according to a second embodiment of the present invention is described below. The variable valve timing control apparatus according to the second embodiment is different from the one according to the first embodiment with respect to the structure of a hydraulic pressure control valve
200
. The same elements are denoted with the identical reference numerals employed by the first embodiment and the description thereof are omitted for simplifying the specification.
The hydraulic pressure control valve
200
illustrated in
FIG. 9
forms the oil pressure circuit C having the oil pump
110
driven by the engine
1
, the oil pan
120
thereof. Further, the hydraulic pressure control valve
200
is the variable electromagnetic spool valve for moving a spool
204
against the spring
105
in response to the electric current supplied to the solenoid
103
by the ECU. The ECU controls the duty value (%) of the electric current to be supplied to the solenoid
103
so as to change the stroke amount of the spool
204
. Therefore, the hydraulic pressure control valve
200
is structured to control the fluid supplied to the advance oil path
11
, the retard oil path
12
, the first, second control mechanisms B
1
, B
2
and the fluid drained therefrom.
As being enlarged in
FIG. 10
, the spool
204
is provided with seven land portions
204
a
,
204
b
,
204
c
,
204
d
,
204
e
,
204
f
,
204
g
, six annular grooves
204
h
,
204
l
,
204
k
,
204
l
,
204
m
,
204
n
, six annular grooves
150
f
,
150
g
,
150
h
,
150
i
,
150
j
,
150
k
, and connecting ports
204
p
,
204
q
,
204
r
. Each annular groove
204
h
,
204
j
,
204
k
,
204
l
,
204
m
,
204
n
is defined between each land portion. Each connecting port
204
p
,
204
q
,
204
r
is defined for connecting each annular groove
204
h
,
204
k
,
204
n
with the drain port
107
. A lap amount L1 between the annular grooves
204
n
,
150
k
is set to be equal to or smaller than a lap amount L2 between the annular grooves
150
i
and
204
m
. The lap amount L2 is set to be smaller than a lap amount L3 between the annular grooves
204
h
,
150
f
. The lap amount L3 is set to be equal to or smaller than a lap amount L4 between the annular grooves
150
f
,
204
j
. The lap amount L4 is set to be smaller than a lap amount L5 between the annular grooves
204
k
,
150
h
. The lap amount L5 is set to be equal to or smaller than a lap amount L6 between the annular grooves
204
m
,
150
j
. The lap amount L6 is set to be smaller than a lap amount L7 between the annular grooves
150
h
,
204
l
. The lap amount L7 is set to be equal to or smaller than a lap amount L8 between the annular grooves
150
j
,
204
n
. An annular groove
204
s
communicating with the advance port
102
is connected to the annular grooves
204
m
and
204
n.
When the spool
204
is positioned as illustrated in
FIG. 10
, i.e. when the solenoid
103
is under the excited condition with the duty ratio of 0%, the communication between the first supply port
106
a
and the lock port
108
is interrupted by the land portion
204
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
204
d
, and yet the communication between the second supply port
106
b
and the advance port
102
is established by the land portion
204
e
. The lock port
108
can be allowed to communicate with the drain port
107
via the annular groove
204
h
and the connecting port
204
p
by means of the land portion
204
b
. The retard port
101
can be also allowed to communicate with the drain port
107
via the annular groove
204
k
and the connecting port
204
q
by means of the land portion
204
d
. The advance port
102
can be also allowed to communicate with the drain port
107
via the annular groove
204
n
and the connecting port
204
r
by means of the land portion
204
g
. Therefore, the oil can be drained from the retard port
101
, the advance port
102
, the lock port
108
. Therefore, the oil can be drained from the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
, the retard angle chamber R
2
, and the advance angle chamber R
1
.
When the spool
204
is positioned as illustrated in
FIG. 11
, the communication between the first supply port
106
a
and the lock port
108
is interrupted by the land portion
204
b
. The lock port
108
can be allowed to communicate with the drain port
107
via the annular groove
204
h
and the connecting port
204
p
by means of the land portion
204
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
204
d
. The communication between the second supply port
106
b
and the advance port
102
can be established by the land portion
204
e
. The communication between the advance port
102
and the drain port
107
is interrupted by the land portion
204
g
. The retard port
101
can be allowed to communicate with the drain port
107
via the annular groove
104
k
and the communicating port
204
q
by means of the land portion
204
d
. Therefore, the oil can be supplied to the advance angle chamber R
1
. On the other hand, the oil can be drained from the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
and the retard angle chamber R
2
.
When the spool
204
is positioned as illustrated in
FIG. 12
, the communication between the first supply port
106
a
and the lock port
108
can be established by the land portion
204
b
and yet the communication between the first supply port
106
a
and the drain port
107
is interrupted thereby. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
204
d
. The retard port
101
can be allowed to communicate with the drain port
107
via the annular groove
204
k
and the connecting port
204
q
by means of the land portion
204
d
. The advance port
102
can be allowed to communicate with the second supply port
106
b
via the annular grooves
204
l
,
204
m
by means of the land portion
204
e
. The communication between the advance port
102
and the drain port
107
is interrupted by the land portions
204
f
,
204
g
. Therefore, the oil can be supplied to the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
and the advance angle chamber R
1
. On the other hand, the oil can be drained from the retard angle chamber R
2
.
When the spool
204
is positioned as illustrated in
FIG. 13
, the communication between the first supply port
106
a
and the lock port
108
can be established by the land portion
204
b
. The communication between the second supply port
106
b
and the retard port
101
is interrupted by the land portion
204
d
. The communication between the second supply port
106
b
and the advance port
102
is also interrupted by the land portion
204
f
. The communication between the retard port
101
and the drain port
107
is interrupted by the land portion
204
d
. The communication between the advance port
102
and the drain port
107
is interrupted by the land portions
204
f
,
204
g
. Therefore, the oil can be supplied to the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
. The supply of the oil to the chambers R
1
, R
2
and the drain of the oil therefrom can be interrupted.
When the spool
204
is positioned as illustrated in
FIG. 14
, the communication between the first supply port
106
a
and the lock port
108
can be established by the land portion
204
b
. The retard port
101
can be allowed to communicate with the second supply port
106
b
via the annular groove
204
l
by means of the land portion
204
d
. The communication between the second supply port
106
b
and the advance port
102
is interrupted by the land portion
204
f
. The advance port
102
can be allowed to communicate with the drain port
107
via the annular groove
204
n
and the connecting port
204
r
by means of the land portion
204
f
. Therefore, the oil can be supplied to the lock grooves
21
k
,
21
l
of the first, second control mechanisms B
1
, B
2
and the retard angle chamber R
2
. On the other hand, the oil can be drained from the advance angle chamber R
1
.
The above described hydraulic pressure control valve
200
according to the second embodiment of the present invention includes the ECU for controlling the exciting operation of the solenoid
103
based upon the predetermined control routine.
When starting the engine
1
that has been stopped, the electric current is not supplied to the solenoid
103
of the hydraulic pressure control valve
200
by the ECU. Therefore, the spool
204
is maintained as illustrated in FIG.
10
. The, oil discharged from the oil pump
110
can not be supplied to the variable valve timing control apparatus by the hydraulic pressure control valve
200
. At the same time, the oil can be drained form the first control mechanism B
1
, the second control mechanism B
2
, the advance angle chamber R
1
, the retard angle chamber R
2
via the hydraulic circuit C. Therefore, the first, second control mechanisms B
1
, B
2
are locked in response to the oil drained therefrom. In this case, the oil has been drained from the chambers R
1
, R
2
. Therefore, the rotation of the rotor
21
relative to the housing
30
can be performed smoothly by the variable torque applied from the cam shaft
10
. When the rotational range of the rotor
21
relative to the housing
30
is increased when starting the engine
1
and when the phase of the rotor
21
relative to the housing
30
is positioned at the advance side of the intermediate phase position or at the retard side thereof, the phase of the rotor
21
relative to the housing
30
can be varied to the intermediate phase position due to the variable torque applied from the cam shaft
10
. When the rotor
21
relative to the housing
30
is positioned at the intermediate phase position, the first, second control mechanisms B
1
, B
2
can be accommodated in the lock grooves
21
k
,
21
l
. Therefore, the rotation of the rotor
21
relative to the housing
30
can be restrained. Further, the phase of the rotor
21
relative to the housing
30
can be maintained at the intermediate phase position.
According to the variable valve timing control apparatus of the second embodiment as well as the one of the first embodiment of the present invention, the rotor
21
can be maintained at the intermediate phase position by the first, second control mechanisms B
1
, B
2
. When the chambers R
1
and R
2
are filled with the oil, the volume of the advance angle chamber R
1
or the retard angle chamber R
2
is varied (especially decreased) by the vane
23
in response to the rotation of the rotor
21
. Therefore, the oil pressure filled in the advance angle chamber R
1
or the retard angle chamber R
2
is varied (especially increased). However, the first fluid path for operating the first, second control mechanisms B
1
, B
2
is defined independently of the second fluid path for supplying the oil to the advance angle chamber R
1
and the retard angle chamber R
2
. Therefore, the oil pressure variation is not transmitted to the lock grooves
21
k
,
21
l.
As described above, even when the oil is supplied to the advance angle chamber R
1
or the retard angle chamber R
2
upon starting the engine
1
, the lock plates
61
,
63
of the first, second control mechanisms B
1
, B
2
can be prevented from being released due to the variable torque applied from the cam shaft
10
. Further, the lock plates
61
,
63
can be prevented from being maintained under the released condition, whereby the phase of the rotor
21
relative to the housing
30
can be assured at the intermediate phase position. Therefore, the noise caused by the variation of the phase of the rotor
21
relative to the housing
30
can be avoided. Therefore, the starting performance of the engine
1
can be prevented from being degraded.
According to the second embodiment, when the hydraulic pressure control valve
200
is set as illustrated in
FIG. 10
, the oil is drained from the advance angle chamber R
1
, the retard angle chamber R
2
, the first, second control mechanisms B
1
, B
2
when starting the engine
1
. Therefore, the phase of the rotor
21
relative to the housing
30
is operatively maintained at the intermediate phase position by the first, second control mechanisms B
1
, B
2
. On the other hand, when the hydraulic pressure control valve
200
is set as illustrated in
FIG. 11
, the phase of the rotor
21
relative to the housing
30
is maintained at the intermediate phase position by the oil filled in the advance angle chamber R
1
or the retard angle chamber R
2
. When the hydraulic pressure control valve
200
is shifted from the condition illustrated in
FIG. 10
to the other condition illustrated in
FIG. 11
, the first, second control mechanisms B
1
, B
2
can be still maintained to be locked even while the oil has been supplied to the advance angle chamber R
1
or the retard angle chamber R
2
. Therefore, the lock plates
61
,
63
can be prevented from being disengaged from the lock grooves
21
k
,
21
l
due to the oil pressure variation when the sufficient oil has not been supplied to the advance angle chamber R
1
or the retard angle chamber R
2
(or both of the chambers R
1
, R
2
). In this case, the phase of the rotor
21
relative to the housing
30
can be prevented from being fluctuated when the phase holding by the locked first, second control mechanisms B
1
, B
2
is shifted to the other phase holding by the oil supplied to the advance angle chamber R
1
or the retard angle chamber R
2
.
As described above, the electric current supplied to the solenoid
103
is controlled by the ECU based upon the predetermined control routine. Therefore, according to the second embodiment of the present invention, when the engine
1
is normally activated, the rotational phase of the rotor
21
relative to the housing
30
can be hence adjusted at the predetermined phase within the range between the most retarded angle phase, in which the volume of the advance angle chamber R
1
is set at the minimum level and the volume of the retard angle chamber R
2
at the maximum level as illustrated in
FIG. 4
, and the most advanced angle phase, in which the volume of the retard angle chamber R
2
is set at the minimum level and the volume of the advance angle chamber R
1
at the maximum level as illustrated in FIG.
3
. Therefore, when the engine
1
is activated, the valve opening/closing timing of the intake valve and the exhaust valve can be adjusted between the opening/closing operation under the most retarded angle condition and the opening/closing operation under the most advanced angle condition, when needed. When the rotor
21
is rotated in the advance angle direction, the hydraulic pressure control valve
200
is adjusted to be set as illustrated in
FIG. 12
by supplying the solenoid
103
with the electric current having the duty ratio controlled by the ECU. When the rotor
21
is rotated in the retard direction, the hydraulic pressure control valve
100
is adjusted to be set as illustrated in
FIG. 14
by supplying the solenoid
103
with the electric current having the duty ratio controlled by the ECU. When the phase of the rotor
21
relative to the housing
30
is maintained at the predetermined phase, the electric current having the controlled duty ratio is supplied to the solenoid
103
so as to set the hydraulic pressure control valve
200
as illustrated in FIG.
13
. In this case, the oil can be supplied to the first, second control mechanisms B
1
, B
2
, wherein the lock plates
61
,
63
are maintained under the released condition. Assuming that the phase of the rotor
21
is shifted from the actual position in the advance angle direction (or in the retard direction), the rotor
21
can be rotated smoothly by supplying the oil to the advance angle chamber R
1
and the retard angle chamber R
2
.
When the oil is supplied to one of the advance angle chamber R
1
and the retard angle chamber R
2
, the oil is also supplied to the first, second control mechanisms B
1
, B
2
. Therefore, Therefore, when the rotor
21
is rotated in the advance angle direction or in the retard direction, the first, second control mechanisms B
1
, B
2
are unlocked. Therefore, the relative rotation of the rotor
21
can be performed smoothly without being blocked.
The unlock operation of the first, second control mechanisms B
1
, B
2
can be performed independently of the oil supply to the chambers R
1
, R
2
. Therefore, the first, second control mechanisms B
1
, B
2
can be unlocked after supplying the sufficient oil to the chambers R
1
, R
2
. Therefore, the variation of the phase of the rotor
21
can be prevented. Further, the first, second control mechanisms B
1
, B
2
are not affected by the variable torque in each chamber R
1
, R
2
. Therefore, the locking operation and the releasing operation of the first, second control mechanisms B
1
, B
2
can be prevented from being performed by mistake due to the variable torque.
According to the first, second embodiments of the present invention, the first, second control mechanisms (the relative rotation control mechanism) B
1
, B
2
are unlocked when the oil is supplied to the lock grooves
21
k
,
21
l
and are locked when the oil is drained therefrom. Alternatively, the first, second control mechanisms B
1
, B
2
can be unlocked when the oil is drained from the lock grooves
21
k
,
21
l
and can be locked when the oil is supplied thereto.
Further, according to the first embodiment of the present invention, the hydraulic pressure control valve
100
is shifted from the condition illustrated in
FIG. 5
to the condition illustrated in
FIG. 8
via the conditions illustrated in
FIGS. 6
,
7
, in response to the electric current supplied to the solenoid
103
. Alternatively, the hydraulic pressure control valve
100
can be set as illustrated in
FIG. 8
when the electric current is not supplied thereto and can be shifted from the condition illustrated in
FIG. 8
to the condition illustrated in
FIG. 5
via the conditions illustrated in
FIG. 7. 6
.
Further, according to the second embodiment of the present invention, the hydraulic pressure control valve
200
is shifted from the condition illustrated in
FIG. 10
to the condition illustrated in
FIG. 14
via the conditions illustrated in
FIGS. 11
,
12
,
13
, in response to the electric current supplied to the solenoid
103
. Alternatively, the hydraulic pressure control valve
200
can be set as illustrated in
FIG. 14
when the electric current is not supplied thereto and can be shifted from the condition illustrated in
FIG. 14
to the condition illustrated in
FIG. 10
via the conditions illustrated in
FIGS. 13
,
12
,
11
.
Further, as illustrated in
FIG. 1
, an orifice L can be provided for the oil path S
21
connecting the first supply port
106
a
and the oil pump
110
. Accordingly, the oil pressure variation caused by the oil pump
110
can be prevented from being transmitted to the lock grooves
21
k
,
21
l
via the hydraulic pressure control valve
100
. Therefore, the lock plates
61
,
63
are prevented from repeatedly being engaged to the lock grooves
21
k
,
21
l
and disengaged therefrom due to the oil pressure variation. That is, the noise due to the repeated engaging/disengaging operations can be avoided. Further, the phase of the rotor
21
relative to the housing
30
can be prevented from not being assured by the first, second control mechanisms (the relative rotation control mechanism) B
1
, B
2
due to the disengagement of the lock plates
61
,
63
. Further, the oil pressure variation caused by the volume variation in the advance angle chamber R
1
in response to the rotation of the rotor
21
, (i.e. the vane
23
) is prevented from being transmitted to the lock grooves
21
k
,
21
l
via the second fluid path (the oil bore
21
f
, the central inner bore
21
b
, the axial oil path
41
, the advance oil path
11
, the oil paths
13
,
14
), the advance port
102
of the hydraulic pressure control valve
100
(or the hydraulic pressure control valve
200
), an oil path (a fourth fluid path of the fluid pressure passage) defined by the annular groove
104
k
(or the annular groove
204
m
) in the hydraulic pressure control valve
100
(or the hydraulic pressure control valve
200
), the second supply port
106
b
, the oil path S
22
, and the oil path S
21
. In the same manner, the oil pressure variation caused by the volume variation in the retard angle chamber R
2
in response to the rotation of the rotor
21
, i.e. the vane
23
is prevented from being transmitted to the lock grooves
21
k
,
21
l
via the second fluid path (the oil bores
21
g
,
21
c
, the oil path
42
, the retard oil path
12
, the oil paths
15
,
16
), the retard port
101
of the angle pressure control valve
100
(or the hydraulic pressure control valve
200
), an oil path (the fourth fluid path) defined by the annular groove
104
k
(or the annular groove
204
l
) in the hydraulic pressure control valve
100
(or the hydraulic pressure control valve
200
), the second supply port
106
b
, the oil path S
22
, and the oil path S
21
.
Therefore, the lock plates
61
,
63
can be prevented from being repeatedly engaged with the lock grooves
21
k
,
21
l
and disengaged therefrom, wherein the noise due to the repeated engaging/disengaging operation can be avoided.
Further, the phase of the rotor
21
relative to the housing
30
can be prevented from not being assured by the relative rotation control mechanisms B
1
, B
2
due to the disengagement of the lock plates
61
,
63
.
As described above, the orifice L can be applicable to both first and second embodiments. Although the orifice L is provided for the oil path S
21
according to the first, second embodiments of the present invention, the orifice L can, be defined by partially diminishing a cross-sectional area of the oil path S
21
. Further, the oil path S
21
can be defined by adjusting a width or length of the oil path
150
d
defined in the sleeve portion
150
, the width or length of the oil paths
150
e
,
150
a
connecting the oil path
150
d
with the annular grooves
104
h
,
204
j.
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 embodiment disclosed. Further, the embodiment described herein is to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit 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.
Claims
- 1. A variable valve timing control apparatus, comprising:a housing integrally rotated with one of a crank shaft of an internal combustion engine and a cam shaft thereof; a rotor provided in the housing and integrally rotated with the other one of the crank shaft and the cam shaft; a hydraulic chamber defined between the housing and the rotor; a vane assembled in the rotor for dividing the hydraulic chamber into an advance angle chamber and a retard angle chamber; a relative rotation control mechanism for restraining a relative rotation between the rotor and the housing at an intermediate phase position between the most advanced angle phase position and the most retarded angle phase position in response to a fluid supplied to the relative rotation control mechanism and a fluid drained therefrom; and a fluid pressure passage for controlling the fluid supplied to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for controlling the fluid drained therefrom, wherein the fluid pressure passage includes a first fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a second fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom; wherein the fluid pressure passage further includes a hydraulic pressure control valve for supplying the fluid to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for draining the fluid therefrom, wherein the hydraulic pressure control valve includes a third fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a fourth fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom.
- 2. A variable valve timing control apparatus, according to claim 1, wherein the hydraulic pressure control valve drains the fluid from the advance angle chamber and the retard angle chamber.
- 3. A variable valve timing control apparatus, according to claim 2, wherein the hydraulic pressure control valve is controlled for supplying the fluid to the relative rotation control mechanism after supplying the fluid to at least one of the advance angle chamber and the retard angle chamber when the relative rotation of the rotor and the housing is shifted from a first condition to be maintained at the intermediate phase position by the relative rotation control mechanism to a second condition to be maintained at the intermediate phase position by a fluid pressure supplied to at least one of the advance angle chamber and the retard angle chamber.
- 4. A variable valve timing control apparatus, according to claim 1, wherein the first fluid path communicates with the relative rotation control mechanism via the cam shaft and the rotor, the second fluid path communicates with the advance angle chamber and the retard angle chamber via the cam shaft and the rotor, the third fluid path is defined in the hydraulic pressure control valve and communicates with the first fluid path, and the fourth fluid path is defined in the hydraulic pressure control valve and communicates with the second fluid path.
- 5. A variable valve timing control apparatus, according to claim 4, further comprising:an oil pump driven by the internal combustion engine; an oil pan for supplying the fluid to the relative rotation control mechanism, the advance angle chamber, and the retard angle chamber and for draining the fluid therefrom; and an oil pressure circuit for connecting the hydraulic pressure control valve with the oil pan via the oil pressure circuit, wherein the fluid is supplied to the relative rotation control mechanism from the oil pan via the oil pressure circuit, the third fluid path, and the first fluid path, the fluid is supplied to at least one of the advance angle chamber and the retard angle chamber from the oil pan via the oil pump, the fourth fluid path, and the second fluid path, the fluid is drained from the relative rotation control mechanism to the oil pan via the first fluid path, the third fluid path, and the oil pressure circuit, and the fluid is drained from at least one of the advance angle chamber and the retard angle chamber to the oil pan via the second fluid path, the fourth fluid path, and the oil pressure circuit, wherein the fluid is circulated between the oil pan and the relative rotation control mechanism, the advance angle chamber, the retard angle chamber.
- 6. A variable valve timing control apparatus, according to claim 5, further comprising:an electronic control unit for controlling the hydraulic pressure control valve by supplying an electric current thereto; the hydraulic pressure control valve including; a solenoid to be excited with the electric current supplied by the electronic control unit; and a spool movable in response to the electric current supplied to the solenoid, wherein the third fluid path is connected to the first fluid path in response to the position of the spool for supplying the fluid to the relative rotation control mechanism, and the fourth fluid path is connected to the second fluid path in response to the position of the spool for supplying the fluid to at least one of the advance angle chamber and the retard angle chamber.
- 7. A variable valve timing control apparatus, according to claim 5, further comprising:an orifice for preventing an oil pressure variation caused by the oil pump from being transmitted to the relative rotation control mechanism.
- 8. A variable valve timing control apparatus, according to claim 7, further comprising:the oil pressure circuit including: a first supply port for connecting the oil pump with the relative rotation control mechanism via the first and third fluid paths so as to supply the fluid to the relative rotation control mechanism; and a second supply port for connecting the oil pump with the advance angle chamber and the retard angle chamber so as to supply the fluid to at least one of the advance angle chamber and the retard angle chamber, wherein the orifice is provided for the first supply port for preventing an oil pressure variation caused by the oil pump from being transmitted to the relative rotation control mechanism.
- 9. A variable valve timing control apparatus, according to claim 7, wherein the orifice can be defined by reducing a partial cross-sectional area of the first supply port.
- 10. A variable valve timing control apparatus, comprising:a housing integrally rotated with one of a crank shaft of an internal combustion engine and a cam shaft thereof; a rotor provided in the housing and integrally rotated with the other one of the crank shaft and the cam shaft; a hydraulic chamber defined between the housing and the rotor; a vane assembled in the rotor for dividing the hydraulic chamber into an advance angle chamber and a retard angle chamber; a relative rotation control mechanism for restraining a relative rotation between the rotor and the housing at an intermediate phase position between the most advanced angle phase position and the most retarded angle phase position in response to a fluid supplied to the relative rotation control mechanism and a fluid drained therefrom; and a fluid pressure passage which controls the fluid supplied to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and the fluid drained therefrom, the fluid pressure passage including a first fluid path which supplies the fluid to the relative rotation control mechanism and drains the fluid therefrom independently of a second fluid path which supplies the fluid to the advance angle chamber and the retard angle chamber and drains the fluid therefrom, the fluid pressure passage further including a hydraulic pressure control valve which includes both a third fluid path and a fourth fluid path, with the third fluid path supplying the fluid to the relative rotation control mechanism and draining the fluid therefrom independently of the fourth fluid path which supplies the fluid to the advance angle chamber and the retard angle chamber and drains the fluid therefrom.
- 11. A variable valve timing control apparatus, according to claim 10, wherein the hydraulic pressure control valve which includes both the third fluid path and the fourth fluid path includes a spool slidably movable in a sleeve.
- 12. A variable valve timing control apparatus, comprising:a housing integrally rotated with one of a crank shaft of an internal combustion engine and a cam shaft thereof; a rotor provided in the housing and integrally rotated with the other one of the crank shaft and the cam shaft; a hydraulic chamber defined between the housing and the rotor; a vane assembled in the rotor for dividing the hydraulic chamber into an advance angle chamber and a retard angle chamber; a relative rotation control mechanism for restraining a relative rotation between the rotor and the housing at an intermediate phase position between the most advanced angle phase position and the most retarded angle phase position in response to a fluid supplied to the relative rotation control mechanism and a fluid drained therefrom; and a fluid pressure passage for controlling the fluid supplied to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for controlling the fluid drained therefrom, wherein the fluid pressure passage includes a first fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a second fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom and a hydraulic pressure control valve for supplying the fluid to the advance angle chamber, the retard angle chamber, and the relative rotation control mechanism and for draining the fluid therefrom, and the hydraulic pressure control valve includes a third fluid path for supplying the fluid to the relative rotation control mechanism and for draining the fluid therefrom independently of a fourth fluid path for supplying the fluid to the advance angle chamber and the retard angle chamber and for draining the fluid therefrom, and the hydraulic pressure control valve is controlled for supplying the fluid to the relative rotation control mechanism after supplying the fluid to at least one of the advance angle chamber and the retard angle chamber when the relative rotation between the rotor and the housing is shifted from a first condition to be maintained at the intermediate phase position by the relative rotation control mechanism to a second condition to be maintained at the intermediate phase position by a fluid pressure supplied to at least one of the advance angle chamber and the retard angle chamber.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-197372 |
Jun 2001 |
JP |
|
US Referenced Citations (7)
Number |
Name |
Date |
Kind |
5957098 |
Fukuhara et al. |
Sep 1999 |
A |
6035819 |
Nakayoshi et al. |
Mar 2000 |
A |
6053138 |
Trzmiel et al. |
Apr 2000 |
A |
6053139 |
Eguchi et al. |
Apr 2000 |
A |
6058897 |
Nakayoshi |
May 2000 |
A |
6386164 |
Mikame et al. |
May 2002 |
B1 |
6553951 |
Ogawa |
Apr 2003 |
B2 |
Foreign Referenced Citations (4)
Number |
Date |
Country |
197 56 017 |
Jun 1999 |
DE |
0 857 859 |
Aug 1998 |
EP |
0 924 382 |
Jun 1999 |
EP |
2001-41012 |
Feb 2001 |
JP |