Information
-
Patent Grant
-
6318319
-
Patent Number
6,318,319
-
Date Filed
Thursday, September 14, 200024 years ago
-
Date Issued
Tuesday, November 20, 200123 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 9015
- 123 9017
- 123 9018
- 123 9031
- 074 568 R
- 464 1
- 464 2
- 464 160
-
International Classifications
-
Abstract
A valve timing control device disposed between a rotary element synchronously rotating with an engine and a camshaft actuating the engine valve, comprising a housing adapted to rotate with one of the rotary element and the camshaft and a vane rotor within the housing. The vane rotor has an axial bore having an open end and pressure chamber-side fluid passages open to the axial bore and is adapted to rotate with the other of the rotary element and the camshaft. Vanes radially extending from the vane rotor define within the housing fluid pressure chambers communicating with the pressure chamber-side fluid passages, respectively. A fluid control mechanism controls supply and discharge of a hydraulic fluid relative to the fluid pressure chambers. A shaft is received in the axial bore and formed with pressure source-side fluid passages connecting the pressure chamber-side fluid passages with the fluid control mechanism.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a valve timing control device for controlling timings of opening and closing an engine valve during the engine operation.
There is known a valve timing control device of the type, which is disposed between a rotary element rotatively driven by a crank shaft of an internal combustion engine and a cam shaft for actuating an engine valve, i.e., intake or exhaust valve. The valve timing control device is adapted to vary timings of opening and closing the engine valve by rotating the cam shaft relative to the rotary element.
Japanese Patent Application First Publication No. 8-121123 discloses a valve timing control device including a housing rotating with a rotary element driven by a crank shaft of an internal combustion engine, a rotor rotating with a cam shaft and vanes extending from the rotor. The vanes define a plurality of hydraulic fluid chambers within the housing. The device also includes a mechanism for supplying a hydraulic fluid to the chambers and discharging the hydraulic fluid therefrom. The housing and the rotor are relatively rotated by a difference of the fluid pressure within the chambers. Fluid communication between the mechanism and the chambers is established via fluid passages formed in the rotor and fluid passages formed in the cam shaft or a rotating support fixed to the cam shaft and the rotor. The rotor has an axial end face mating with an axial end face of the cam shaft or an axial end face of the rotating support. The fluid passages of the rotor and the fluid passages of the cam shaft or the rotating support are open to the corresponding axial end faces, respectively, and in axial alignment. Fluid communication between fluid paths of the mechanism and the fluid passages of the cam shaft or rotating support is established between an outer circumferential surface of the cam shaft or rotating support and an inner circumferential surface of a journal supporting the cam shaft or the rotating support.
SUMMARY OF THE INVENTION
In the conventionally proposed technique described above, it is required to increase an axial dimension of the cam shaft to assure the fluid communication between the outer circumferential surface of the cam shaft and the inner circumferential surface of the journal. This will cause an increase in dimension of the internal combustion engine as a whole, resulting in a great modification of design of the existing internal combustion engine to which the conventionally proposed valve timing control device is applied. On the other hand, it is required to increase a size of the valve timing control device to assure the fluid communication between the outer circumferential surface of the rotating support and the inner circumferential surface of the journal.
It is an object of the present invention to provide a valve timing control device reduced in size and applicable to the existing internal combustion engine.
According to one aspect of the present invention, there is provided a valve timing control device for varying an opening and closing timing of an engine valve in an internal combustion engine, the device being disposed between a rotary element synchronously rotating with the engine and a camshaft actuating the engine valve, the device comprising:
a housing adapted to rotate with one of the rotary element and the camshaft;
a vane rotor disposed within said housing, said vane rotor having an axial bore having an open end and pressure chamber-side fluid passages open to said axial bore, said vane rotor being adapted to rotate with the other of the rotary element and the camshaft;
a vane radially extending from said vane rotor and defining within said housing at least a pair of fluid pressure chambers communicating with said pressure chamber-side fluid passages, respectively, said fluid pressure chambers being circumferentially disposed within said housing;
a fluid control mechanism for supplying a hydraulic fluid to said fluid pressure chambers and discharging the hydraulic fluid therefrom; and
a shaft received in said axial bore of said vane rotor through said open end, said shaft being formed with pressure source-side fluid passages communicating with said pressure chamber-side fluid passages and said fluid control mechanism.
According to a further aspect of the present invention, there is provided a valve timing control device, comprising:
a housing;
a vane rotor with at least one vane and rotatable relative to said housing, said vane rotor having an axial bore and fluid passages open to the axial bore;
at least a pair of fluid pressure chambers defined by the housing and the vane rotor with the vane, said fluid passages being open to the fluid pressure chambers, respectively;
a lock mechanism for restricting relative rotation of the housing and the rotor, said lock mechanism comprising a fluid pressure chamber fluidly communicated with one of the pair of fluid pressure chambers;
a fluid control mechanism for supplying a hydraulic fluid to the fluid pressure chambers and discharging the hydraulic fluid therefrom;
a shaft received in the axial bore of the rotor;
first communication fluid path communicating with one of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said first communication fluid path being formed in the shaft; and
second communication fluid path communicating with the other of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said second communication fluid path being formed in the shaft.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
shows a valve timing control device for an internal combustion engine, of a first embodiment, according to the present invention, partially in section taken along an axis X;
FIG. 2
is a section taken along line
2
—
2
of
FIG. 1
with omitting a shaft and a connecting bolt;
FIG. 3
is a section taken along line
3
—
3
of
FIG. 1
with omitting the shaft;
FIG. 4
is an elevation of the device as viewed from arrow
4
of
FIG. 1
; and
FIG. 5
is a diagram similar to
FIG. 1
, but showing a second embodiment of the device according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to
FIGS. 1-4
, a first preferred embodiment of a valve timing control device for an internal combustion engine, according to the present invention, is explained.
In
FIG. 1
, a reference numeral
1
denotes a cam shaft adapted to actuate an engine valve, namely, an intake or exhaust valve. In this embodiment, the cam shaft
1
is adapted for driving the intake valve. The cam shaft
1
is rotatably supported by a bearing
2
fixed to an engine cylinder head, not shown. The cam shaft
1
is formed with cams, not shown, on its base portion, not shown, located on the right side of the bearing
2
in FIG.
1
. The cams actuate the intake valve to open and close. The cam shaft
1
is rotatably driven by a rotary element
3
synchronously rotated with the engine. In this embodiment, the rotary element
3
is a sprocket rotated by a crank shaft, not shown, of the engine. The rotary element
3
is rotatable relative to the cam shaft
1
by a predetermined angle. The rotary element
3
has an outer gear
8
on an outer circumference thereof, on which a timing chain
9
driven by the crank shaft is wound. The rotary element
3
is connected with a housing
4
of the valve timing control device by means of a connecting bolt
7
and thus rotatable with the housing
4
.
As illustrated in
FIG. 1
, the housing
4
includes an annular shell
5
and an end plate
6
closing one end of the shell
5
. As shown in
FIG. 2
, the shell
5
is formed with a plurality of radially inward extending projections
12
, four projections in this embodiment, circumferentially spaced from each other. The projections
12
define four chambers
13
circumferentially arranged therebetween.
Referring back to
FIG. 1
, the valve timing control device includes a vane rotor
15
that is disposed within the housing
4
so as to be rotatable about a rotation axis X by a predetermined angle relative to the housing
4
. The vane rotor
15
is coaxially arranged with the cam shaft
1
and connected therewith by a connecting bolt
28
. The device has a cylindrical axial bore
27
extending in the rotation axis X and formed by the vane rotor
15
and a sleeve
45
connected with the vane rotor
15
in substantially coaxial alignment therewith. Specifically, the vane rotor
15
includes a hub portion
17
having an inner circumferential surface that defines the axial bore
27
in cooperation with an inner circumferential surface of the sleeve
45
. The hub portion
17
has an axial end wall defining a bottom of the axial bore
27
. The axial bore
27
has an open end at an axial end of the sleeve
45
. The axial end wall of the hub portion
17
has an axially extending bolt hole communicated with the axial bore
27
. The bolt
28
is inserted into the bolt hole via the axial bore
27
so that a head
29
of the bolt
28
is disposed on the bottom of the axial bore
27
. The vane rotor
15
also includes at least one vane
18
, a plurality of vanes
18
in this embodiment, radially outward extending from the hub portion
17
. The hub portion
17
acts as a bearing for the rotary element
3
and the shell
5
of the housing
4
.
As best shown in
FIG. 2
, the vanes
18
, four vanes
18
in this embodiment, are circumferentially spaced from each other. Each of the vanes
18
is disposed within each chamber
13
of the housing
4
and divides the chamber
13
into a pair of fluid pressure chambers
19
and
20
. Fluid communication between the chambers
19
and
20
is prevented using seals
21
and
23
and springs
22
and
24
. The seal
21
is disposed at an inward end of the projection
12
of the shell
5
of the housing
4
and biased by the spring
22
against an outer circumference of the hub portion
17
of the vane rotor
15
. The seal
23
is disposed at an inward end of the vane
18
and biased by the spring
24
against an inner circumference of the shell
5
. The vane rotor
15
includes a pressure chamber-side fluid passage
25
radially extending and communicated with the fluid pressure chamber
19
and a pressure chamber-side fluid passage
26
radially extending and communicated with the fluid pressure chamber
20
. The pressure chamber-side fluid passages
25
and
26
extend through the hub portion
17
and are open to the axial bore
27
at inner ends thereof and the fluid pressure chambers
19
and
20
at outer ends thereof, respectively. The pressure chamber-side fluid passages
25
and
26
are spaced from each other in the axial direction of the axial bore
27
as shown in FIG.
1
. With the arrangement, the housing
4
and the vane rotor
15
are relatively rotatable within a predetermined range of angle by selectively supplying a hydraulic fluid to the fluid pressure chamber
19
or
20
and discharging the fluid therefrom via the pressure chamber-side fluid passage
25
or
26
.
By the selective shift of the hydraulic fluid between the fluid pressure chambers
19
and
20
, the housing
4
connected with the rotary element
3
can be rotated relative to the vane rotor
15
connected with the cam shaft
1
within the predetermined angle range. The housing
4
and the vane rotor
15
thus constitute a relative rotation mechanism for rotating the rotary element
3
relative to the cam shaft
1
.
Disposed between the housing
4
and the vane rotor
15
is a lock mechanism
31
for restricting relative rotation of the housing
4
and the vane rotor
15
. In this embodiment, the lock mechanism
31
includes a lock pin
34
moveably disposed within a cylinder bore
32
of the vane rotor
15
and a lock hole
35
engageable with the lock pin
34
within the housing
4
. The cylinder bore
32
is formed in one of the vanes
18
which has an increased circumferential length as shown in
FIG. 2
, and extends therethrough in the axial direction of the vane rotor
15
. A spring
33
biasing the lock pin
34
toward the lock hole
35
is disposed within the cylinder bore
32
and supported at one end thereof by a spring retainer
36
. The spring retainer
36
is press-fitted into one end of the cylinder bore
32
which is located on a rear end of the lock pin
34
. The spring retainer
36
is preferably made of a material having hardness higher than that of the vanes
18
. The spring retainer
36
has a vent groove
37
in a predetermined outer circumferential portion thereof through which the cylinder bore
32
is exposed to atmospheric air. The lock pin
34
is formed of a generally cylindrical shape and has a tapered closed-end portion formed with a recess
38
and a blind hole
39
open to the rear end face. An opposite end of the spring
33
is supported at the bottom of the blind hole
39
. The thus constructed lock pin
34
is reduced in weight.
The lock hole
35
is formed in a receptacle
40
embedded in the end plate
6
of the housing
4
. The receptacle
40
is made of a material having hardness higher than that of the end plate
6
. The receptacle
40
is in the form of one open ended cup-shape defining the generally cup-shaped lock hole
35
. The receptacle
40
includes a large inner diameter portion at the open end and a small inner diameter portion at the closed end. The small inner diameter portion of the receptacle
40
cooperates with the tapered end portion of the lock pin
34
to define a fluid pressure chamber
41
. The fluid pressure chamber
41
is communicated with the fluid pressure chamber
19
via a fluid hole
42
radially outward extending through the receptacle
40
.
The sleeve
45
is received through an opening of the end plate
6
and connected with the hub portion
17
of the vane rotor
15
. The sleeve
45
axially extends over a connection in which the shell
5
and the end plate
6
are joined together. The sleeve
45
has at its axial end a guide portion
45
a
tapered so as to gradually increase an inner diameter of the sleeve
45
for guiding or easily receiving parts such as seals
58
and
59
explained later. A target plate
46
used for detecting a cam angle is integrally formed with the guide portion
45
a
of the sleeve
45
. The target plate
46
includes a portion radially extending from the guide portion
45
a
. The portion is disposed between the end plate
6
and a cover
50
enclosing the valve timing control device, in the direction of the rotation axis X. A cam angle sensor
48
is mounted to the cover
50
in an opposed relation to the target plate
46
. The cam angle sensor
48
is located perpendicular to the rotation axis X. The cam angle sensor
48
senses concaved and convexed portions formed in an outer periphery of the target plate
46
, to thereby detect the cam angle.
A shaft
49
is disposed within the axial bore
27
in a coaxial relation to the vane rotor
15
and the sleeve
45
. The shaft
49
may be integrally formed with the cover
50
. The shaft
49
includes pressure source-side fluid passages
51
and
52
extending in the axial direction. The pressure source-side fluid passage
51
has an end closed by a plug
53
opposed to the bottom of the axial bore
27
. A branch passage
54
is branched from the pressure source-side fluid passage
51
in an inclined relation thereto and connected with a circumferential groove
55
circumferentially extending in an outer circumferential surface of the shaft
49
. The pressure source-side fluid passage
51
thus is communicated with the pressure chamber-side fluid passage
25
of the vane rotor
15
via an annular space defined by the shaft
49
within the axial bore
27
. The pressure source-side fluid passage
52
is open to an axial end surface of the shaft
49
that is opposed to the bottom of the axial bore
27
. The pressure source-side fluid passage
52
is open to a bottom portion of the axial bore
27
and thus communicated with the pressure chamber-side fluid passage
26
of the vane rotor
15
via the bottom portion of the axial bore
27
.
The seals
58
and
59
are disposed within the annular space between the outer circumferential surface of the shaft
49
and the inner circumferential surfaces of the hub portion
17
and the sleeve
45
. The seals
58
and
59
cooperate to prevent fluid communication between the pressure chamber-side fluid passages
25
and
26
via the annular space. The seals
58
and
59
are arranged spaced from each other in the axial direction of the shaft
49
such that the circumferential groove
55
is disposed therebetween. The seals
58
and
59
divide the axial bore
27
into portions including the bottom portion to which the fluid passage
26
is open, an open-end portion located near the guide portion
45
a
of the sleeve
45
, and an intermediate portion between the bottom portion and the open-end portion, to which the circumferential groove
55
is open. The seal
58
is located within the open-end portion of the axial bore
27
. The seal
58
is received in a seal groove
60
circumferentially extending on the outer circumferential surface of the shaft
49
and in contact with the inner circumferential surface of the sleeve
45
. On the other hand, the seal
59
is located within the bottom portion of the axial bore
27
. The seal
59
is received in a seal groove
61
circumferentially extending in the outer circumferential surface of the shaft
49
and in contact with the inner circumferential surface of the hub portion
17
. In this embodiment, the seal
59
is constituted by two axially spaced seals received in two grooves as the seal groove
61
which are arranged corresponding to the seals. The sleeve
45
contacted with the seal
58
and the vane rotor
15
contacted with the seal
59
may be made of a high hardness material such as an iron-based material.
The fluid control mechanism
66
is adapted to supply hydraulic fluid to the fluid pressure chambers
19
and
20
and discharge the hydraulic fluid therefrom. Specifically, the fluid control mechanism
66
is connected with a pump
69
as a fluid pressure source via a supply passage
70
and with a reservoir tank
71
via a drain passage
72
. The fluid control mechanism
66
includes fluid paths
67
and
68
communicated with The pressure source-side fluid passages
51
and
52
, a directional control valve
73
selectively establishing fluid communication between the fluid paths
67
and
68
and the supply passage
70
or the drain passage
72
, or selectively preventing the fluid communication therebetween, and a controller
74
controlling the directional control valve
73
. In this embodiment, as shown in
FIG. 4
, the fluid paths
67
and
68
are formed in the cover
50
and connected with the pressure source-side fluid passages
51
and
52
at substantially a right angle relative thereto. The directional control valve
73
is disposed within the cover
50
and it may be a four-port three-position valve as shown in FIG.
1
. The controller
74
receives various signals indicative of operating conditions of the engine.
The fluid control mechanism
66
is connected with the pressure chamber-side fluid passage
25
of the vane rotor
15
via the pressure source-side fluid passage
51
, the branch passage
54
, the circumferential groove
55
and the intermediate portion of the axial bore
27
. Thus, the fluid passage
51
, the branch passage
54
, the groove
55
and the intermediate portion of the axial bore
27
constitute one communication fluid path connecting the pressure chamber-side fluid passage
25
of the vane rotor
15
with the fluid control mechanism
66
. The fluid control mechanism
66
is also connected with the pressure chamber-side fluid passage
26
of the vane rotor
15
via the pressure source-side fluid passage
52
and the bottom portion of the axial bore
27
. The fluid passage
52
and the bottom portion of the axial bore
27
constitute the other communication fluid path connecting the pressure chamber-side fluid passage
26
of the vane rotor
15
with the fluid control mechanism
66
.
When the pump
69
is not conditioned for supplying sufficient hydraulic fluid upon startup of the engine or when the controller
74
receives the signal indicative of maintaining the most delayed state of the cam shaft
1
, the vane rotor
15
is placed in a most delayed position relative to the housing
4
as shown in FIG.
2
. In this state, the lock pin
34
of the lock mechanism
31
is urged toward the lock hole
35
by the spring
33
so that the tapered end portion of the lock pin
34
is engaged into the lock hole
35
as shown in FIG.
1
. The housing
4
and the vane rotor
15
are thus connected with each other. This allows a driving torque transmitted from the crankshaft to the rotary element
3
via the timing chain
9
, to be further transmitted to the cam shaft
1
via the housing
4
and the vane rotor
15
. Thus, the cam shaft
1
is rotated to actuate the intake valve of the engine. At this time, each vane
18
of the vane rotor
15
is not in contact with a side face of each projection
12
defining the chamber
13
within the housing
4
. When the vane rotor
15
is in the most delayed position relative to the housing
4
, the relative rotation of the housing
4
and the vane rotor
15
is prevented by the engagement between the lock pin
34
and the lock hole
35
. The vane
18
can be restrained from being impinged against the side face of the projection
12
even if a reverse, i.e., positive or negative, torque is applied to the cam shaft
1
. This can effectively avoid the occurrence of noise caused by the impingement of the vane
18
against the side face of the projection
12
.
Next, in the case of advancing control, the directional control valve
73
is controlled by the controller
74
so as to establish the fluid communication between the fluid path
67
and the supply passage
70
and at the same time establish the fluid communication between the fluid path
68
and the drain passage
72
. The hydraulic fluid from the pump
69
is fed to the fluid pressure chamber
19
via the fluid path
67
, the pressure source-side fluid passage
51
, the branch passage
54
, the circumferential groove
55
and the pressure chamber-side fluid passage
25
. Simultaneously, the hydraulic fluid within the fluid pressure chamber
20
is discharged to the drain passage
72
via the pressure chamber-side fluid passage
26
, the bottom portion of the axial bore
27
, the pressure source-side fluid passage
52
and the fluid path
68
.
The hydraulic fluid within the fluid pressure chamber
19
then is introduced into the fluid pressure chamber
41
within the lock hole
35
of the receptacle
40
through the fluid hole
42
. With the introduction of the hydraulic fluid into the fluid pressure chambers
19
and
41
, the fluid pressures within the fluid pressure chambers
19
and
41
increase. The increased fluid pressure within the fluid pressure chamber
41
is applied to the lock pin
34
so that the lock pin
34
is urged toward the spring retainer
36
against the spring force of the spring
33
and retarded into the cylinder bore
32
of the vane
18
. This causes the tapered end portion of the lock pin
34
to be disengaged from the lock hole
35
, allowing disconnection of the vane rotor
15
from the housing
4
. Simultaneously, the increased fluid pressure within the fluid pressure chamber
19
is applied to the side face of the vane
18
to rotate the vane rotor
15
relative to the housing
4
in a clockwise direction R shown in
FIG. 2
, namely, in an advancing direction. As a result, the cam shaft
1
and the rotary element
3
are allowed to rotate relative to each other so that a rotational phase of the cam shaft
1
relative to the crankshaft can be changed. The cam shaft
1
can be brought into the advanced position and then the opening and closing timings of the intake valve driven by the cam shaft
1
can be advanced. When the rotational phase of the cam shaft
1
is advanced and the vane rotor
15
is placed in a most advanced position relative to the housing
4
, the lock pin
34
is kept within the cylinder bore
32
by the increased fluid pressure within the fluid pressure chamber
41
and the tapered end portion of the lock pin
34
is free from the contact with the end plate
6
of the housing
4
.
Subsequently, when the directional control valve
73
of the fluid control mechanism
66
is controlled by the controller
74
so as to establish the fluid communication between the fluid path
68
and the supply passage
70
and at the same time establish the fluid communication between the fluid path
67
and the drain passage
72
, the hydraulic fluid from the pump
69
is introduced into the fluid pressure chamber
20
via the pressure source-side fluid passage
52
, the bottom portion of the axial bore
27
and the pressure chamber-side fluid passage
26
and simultaneously the fluid within the fluid pressure chamber
19
is discharged into the reservoir tank
71
via the pressure chamber-side fluid passage
25
, the circumferential groove
55
, the branch passage
54
, the pressure source-side fluid passage
51
and the fluid path
67
. The fluid pressure within the fluid pressure chamber
19
decreases due to the discharge of the hydraulic fluid within the fluid pressure chamber
19
. The decrease of the fluid pressure associates with the spring force of the spring
33
to permit the lock pin
34
to project toward the lock hole
35
. However, the housing
4
and the vane rotor
15
are kept in the relatively rotatable state until the tapered end portion of the lock pin
34
is brought into the engagement with the lock hole
35
.
The fluid pressure within the fluid pressure chamber
20
increases due to the introduction of the hydraulic fluid into the fluid pressure chamber
20
, while the fluid pressure within the fluid pressure chamber
19
decreases as explained above. The increased fluid pressure within the fluid pressure chamber
20
is applied to the side face of the vane
18
to rotate the vane rotor
15
relative to the housing
4
in a counterclockwise direction as viewed in
FIG. 2
, namely, in a delaying direction. The cam shaft
1
and the rotary element
3
are allowed to rotate relative to each other so that the rotational phase of the cam shaft
1
relative to the crankshaft can be changed. The cam shaft
1
can again come into the delayed position and then the opening and closing timings of the intake valve driven by the cam shaft
1
can be delayed. In such a case that the rotational phase of the cam shaft
1
is delayed and the vane rotor
15
is placed in the most delayed position relative to the housing
4
, the tapered end portion of the lock pin
34
is in the engagement with the lock hole
35
.
Under condition that the vane rotor
15
is being rotated relative to the housing
4
in the advancing direction or delaying direction, when the directional control valve
73
is controlled by the controller
74
so as to prevent the fluid communication between the fluid paths
67
and
68
and the supply passage
70
or the drain passage
72
, the vane rotor
15
is held in an intermediate position relative to the housing
4
between the most delayed position and the most advanced position. In this state, the cam shaft
1
is kept in an intermediate rotational position relative to the rotary member
3
, in which the cam shaft
1
actuates the intake valve at a desired valve timing. In this case, the fluid pressure within the fluid pressure chamber
19
is maintained at a predetermined value without fluid communication with the supply passage
70
and the drain passage
72
. This allows the lock pin
34
to be kept in the disengagement from the lock hole
35
in spite of application of the spring force of the spring
33
to the lock pin
34
. As a result, the housing
4
and the vane rotor
15
are still kept in the relatively rotatable state.
As be apparent from the above discussion, the arrangement of the device of the invention can exhibit the following effects.
The shaft
49
can be neatly disposed within the axial bore
27
without projecting from the valve timing control device in such a manner that the pressure chamber-side fluid passages
25
and
26
are open to the axial bore
27
of the vane rotor
15
and the shaft
49
formed with the pressure source-side fluid passages
51
and
52
is received in the axial bore
27
. This can serve for reducing a dimension of the device. Further, since the cam shaft
1
is not required to have fluid passages for supplying and discharging the hydraulic fluid, the device of the invention can be applied to the existing internal combustion engines. In addition, the head
29
of the bolt
28
connecting the vane rotor
15
with the cam shaft
1
is located on the bottom of the axial bore
27
without projecting the bolt
28
from the device, whereby the device can be reduced in size.
Since the shaft
49
is integrally formed with the cover
50
enclosing the device, the assembly work of the device such as the insertion of the shaft
49
into the axial bore
27
can be facilitated. Further, since the shaft
49
is a stationary member, it is unnecessary to design the dimension of the device for displacement of the shaft
49
.
With the arrangement of the seals
58
and
59
in the annular space between the outer circumferential surface of the shaft
49
and the inner circumferential surface of the hub portion
17
which surrounds the axial bore
27
, the hydraulic fluid within the axial bore
27
can be prevented from leaking through the annular space. This allows the hydraulic fluid to be effectively used, improving a response upon varying the valve timing.
The guide portion
45
a
of the sleeve
45
which is tapered so as to gradually increases the inner diameter, can easily guide outer circumferences of the seals
58
and
59
, serving for readily receiving the seals
58
and
59
into the axial bore
27
.
The sleeve
45
is disposed inside the housing
4
so as to extend over the connection of the shell
5
and the end plate
6
and the seal
58
is in contact with a portion of the inner circumferential surface of the sleeve
45
which is located over the connection of the shell
5
and the end plate
6
. With the arrangement, deterioration of sealing by the seal
58
which will be caused if the seal
58
is directly located in direct contact with the connection of the shell
5
and the end plate
6
, can be avoided. Further, layout of the seal
58
can be selected with variety.
The sleeve
45
and vane rotor
15
made of a high hardness material can be considerably protected from wear caused due to the friction contact with the seals
58
and
59
.
The arrangement in which the fluid paths
67
and
68
of the fluid control mechanism
66
are connected with the pressure source-side fluid passages
51
and
52
at substantially the right angle, can serve for reducing an axial length of the shaft
49
and then a size of the device. Further, since the directional control valve
73
and the fluid paths
67
and
68
of the fluid control mechanism
66
are disposed within the cover
50
integrally formed with the shaft
49
, a continuously extending fluid passage extending from the valve
73
to the pressure source-side fluid passages
51
and
52
of the shaft
49
via the fluid paths
67
and
68
can be provided. This can prevent leakage of the hydraulic fluid.
Referring to
FIG. 5
, a second embodiment of the device of the invention will be explained, which differs from the first embodiment in a sleeve
145
integrally formed with the vane rotor
15
. Like reference numerals denote like parts and therefore detailed explanations therefor are omitted.
As illustrated in
FIG. 5
, the sleeve
145
axially extends from the axial end of the hub portion
17
toward the cover
50
. The sleeve
145
is received in an opening of the target plate
46
formed as a separate part, through the opening of the end plate
6
. The sleeve
145
has at an axial end thereof a guide portion
145
a
for guiding parts such as the seals
58
and
59
, similar to the guide portion
45
a
of the sleeve
45
of the first embodiment.
Although the seal grooves
61
and
62
are formed in the outer circumferential surface of the shaft
49
in the above embodiments, the seal grooves
61
and
62
may be formed in the inner circumferential surface of the sleeve
45
and
145
and the inner circumferential surface of the hub portion
17
. In such a case, the shaft
49
contacted with the seals
58
and
59
may be made of a high hardness material and be formed with a tapered end portion acting as the guide portion.
Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiment described above will occur to those skilled in the art, in light of the above teachings. The scope of the invention is defined with reference to the following claims.
Claims
- 1. A valve timing control device for varying an opening and closing timing of an engine valve in an internal combustion engine, the device being disposed between a rotary element synchronously rotating with a crankshaft and a camshaft actuating the engine valve, the device comprising:a housing adapted to rotate with one of the rotary element and the camshaft; a vane rotor disposed within said housing, said vane rotor having an axial bore having an open end and pressure chamber-side fluid passages open to said axial bore, said vane rotor being adapted to rotate with the other of the rotary element and the camshaft, said vane rotor defines a bottom of the axial bore; a vane radially extending from said vane rotor and defining within said housing at least a pair of fluid pressure chambers communicating with said pressure chamber-side fluid passages, respectively, said fluid pressure chambers being circumferentially disposed within said housing; a fluid control mechanism for supplying a hydraulic fluid to said fluid pressure chambers and discharging the hydraulic fluid therefrom; and a shaft received in said axial bore of said vane rotor through said open end, said shaft being formed with pressure source-side fluid passages communicating with said pressure chamber-side fluid passages and said fluid control mechanism.
- 2. A valve timing control device as claimed in claim 1, further comprising a cover enclosing the valve timing control device, said shaft being integrally formed with the cover.
- 3. A valve timing control device as claimed in claim 2, further comprising a seal preventing fluid communication between the fluid passages via an annular space defined by the shaft within the axial bore of the vane rotor, said seal being disposed within the annular space.
- 4. A valve timing control device as claimed in claim 1, wherein the vane rotor comprises a tapered portion located on the open end of the axial bore, said tapered portion defining an increased diameter of the axial bore.
- 5. A valve timing control device as claimed in claim 3, further comprising a sleeve cooperating with the vane rotor to define the axial bore.
- 6. A valve timing control device as claimed in claim 5, wherein the seal comprises a seal received in a seal groove circumferentially extending in either one of an inner circumferential surface of the sleeve which defines the axial bore, and an outer circumferential surface of the shaft.
- 7. A valve timing control device as claimed in claim 6, wherein either one of the sleeve and the shaft which is in contact with the seal, is made of a high hardness material.
- 8. A valve timing control device as claimed in claim 5, wherein the housing comprises a hollow annular shell and an end plate closing one end of the shell, said sleeve being disposed radially inward the end plate.
- 9. A valve timing control device as claimed in claim 8, further comprising a target plate used for detecting a cam angle.
- 10. A valve timing control device as claimed in claim 9, wherein the target plate is integrally formed with the sleeve.
- 11. A valve timing control device as claimed in claim 1, wherein the vane rotor is connected with the camshaft by means of a bolt, said bolt comprising a head disposed on said bottom of the axial bore of the vane rotor.
- 12. A valve timing control device as claimed in claim 11, wherein one of the pressure source-side fluid passages has one end open to the axial bore of the vane rotor and opposed to the bottom of the axial bore.
- 13. A valve timing control device as claimed in claim 3, wherein the seal comprises a seal received in a seal groove circumferentially extending in either one of an inner circumferential surface of the vane rotor which defines the axial bore, and an outer circumferential surface of the shaft.
- 14. A valve timing control device as claimed in claim 13, wherein either one of the vane rotor and the shaft which is in contact with the seal, is made of a high hardness material.
- 15. A valve timing control device as claimed in claim 1, wherein the fluid control mechanism comprises fluid paths communicated with the pressure source-side fluid passages, said fluid paths being located at substantially a right angle relative to the pressure source-side fluid passages.
- 16. A valve timing control device as claimed in claim 2, wherein the fluid control mechanism comprises a directional control valve, said directional control valve being disposed within said cover.
- 17. A valve timing control device as claimed in claim 1, further comprising a lock mechanism for restricting relative rotation of the housing and the vane rotor, said lock mechanism comprising a fluid pressure chamber fluidly communicated with predetermined ones of the fluid pressure chambers.
- 18. A valve timing control device as claimed in claim 9, further comprising a cam angle sensor detecting the cam angle.
- 19. A valve timing control device as claimed in claim 18, wherein the cam angle sensor is mounted to the cover in an opposed relation to the target plate.
- 20. A valve timing control device as claimed in claim 18, wherein the cam angle sensor is located perpendicular to a rotation axis of the vane rotor.
- 21. A valve timing control device as claimed in claim 9, wherein the target plate comprises a portion disposed between the cover and the end plate in a direction of a rotation axis of the vane rotor.
- 22. A valve timing control device, comprising:a housing; a vane rotor with at least one vane and rotatable relative to said housing, said vane rotor having an axial bore and fluid passages open to the axial bore, said vane rotor defines a bottom of the axial bore; at least a pair of fluid pressure chambers defined by the housing and the vane rotor with the vane, said fluid passages being open to the fluid pressure chambers, respectively; a lock mechanism for restricting relative rotation of the housing and the rotor, said lock mechanism comprising a fluid pressure chamber fluidly communicated with one of the pair of fluid pressure chambers; a fluid control mechanism for supplying a hydraulic fluid to the fluid pressure chambers and discharging the hydraulic fluid therefrom; a shaft received in the axial bore of the rotor; first communication fluid path communicating with one of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said first communication fluid path being formed in the shaft; and second communication fluid path communicating with the other of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said second communication fluid path being formed in the shaft.
- 23. A valve timing control device as claimed in claim 22, further comprising a seal cooperating with the shaft to divide the axial bore into a first portion and a second portion and prevent fluid communication between the first and second portions, said first communication fluid path being open to the first portion, said second communication fluid path being open to the second portion.
- 24. A valve timing control device as claimed in claim 23, wherein the first communication fluid path comprises an axial passage extending in the axial direction of the shaft, a branch passage branched from the axial passage and a circumferential groove communicated with the branch passage and circumferentially extending in an outer circumferential surface of the shaft, and the second communication fluid path comprises a second axial passage extending in the axial direction of the shaft and open to the second portion of the axial bore.
- 25. A valve timing control device as claimed in claim 23, further comprising a cover enclosing the valve timing control device, said shaft being integrally formed with the cover.
- 26. A valve timing control device as claimed in claim 23, wherein the seal comprises a seal mounted to either one of the vane rotor and the shaft.
- 27. A valve timing control device as claimed in claim 25, wherein the housing comprises a hollow annular shell receiving the vane rotor and an end plate closing one end of the shell, said end plate being spaced from the cover.
- 28. A valve timing control device as claimed in claim 27, further comprising a sleeve cooperating with the vane rotor to define the axial bore.
- 29. A valve timing control device as claimed in claim 28, wherein the sleeve is integrally formed with the vane rotor.
- 30. A valve timing control device as claimed in claim 28, wherein the seal comprises a seal mounted to either one of the sleeve and the shaft.
- 31. A valve timing control device as claimed in claim 27, further comprising a target plate used for detecting a cam angle.
- 32. A valve timing control device as claimed in claim 31, further comprising a cam angle sensor detecting the cam angle.
- 33. A valve timing control device as claimed in claim 32, wherein the cam angle sensor is mounted to the cover in an opposed relation to the target plate.
- 34. A valve timing control device as claimed in claim 32, wherein the cam angle sensor is located perpendicular to a rotation axis of the vane rotor.
- 35. A valve timing control device as claimed in claim 31, wherein the target plate comprises a portion disposed between the cover and the end plate in a direction of a rotation axis of the vane rotor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-263970 |
Sep 1999 |
JP |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
5205249 |
Markley et al. |
Apr 1993 |
|
5450825 |
Geyer et al. |
Sep 1995 |
|
5666914 |
Ushida et al. |
Sep 1997 |
|
5988126 |
Strauss et al. |
Nov 1999 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
08-121123 |
May 1996 |
JP |