Information
-
Patent Grant
-
6782854
-
Patent Number
6,782,854
-
Date Filed
Thursday, August 28, 200321 years ago
-
Date Issued
Tuesday, August 31, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Chang; Ching
Agents
- Reed Smith LLP
- Fisher, Esq.; Stanley P.
- Marquez, Esq.; Juan Carlos A.
-
CPC
-
US Classifications
Field of Search
US
- 123 9015
- 123 9016
- 123 9017
- 123 9018
- 123 9027
- 123 9031
- 464 1
- 464 2
- 464 160
-
International Classifications
-
Abstract
A valve timing control device includes a rotation member for opening and closing values, a rotation transmitting member rotatably mounted on the rotation member, a fluid chamber defined between the rotation member and the rotation transmitting member, a vane fitted into a vane groove formed on the rotation member or the rotation transmitting member so as to divide the fluid chamber into a advance angle pressure chamber and a retard angle pressure chamber, the vane groove having contacting portions contacted with the vane and an elastic member disposed between the vane and the rotation member or the rotation transmitting member, wherein the radial length between the bottom portion of the vane groove and a bottom portion side end portion of the contacting portion is larger than a radial length between the bottom portion of the vane groove and an engaging portion of the vane engaged with the elastic member.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority to Japanese Patent Application No. 2002-249249 filed on Aug. 28, 2002, the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a valve timing control device which controls open and close timing of intake or exhaust valves of a combustion engine.
BACKGROUND OF THE INVENTION
A conventional device of this kind is disclosed, for example, in Japanese Patent Laid-Open Publication No. 11-101107. This device is disposed between a crank shaft of a combustion engine and a cam shaft for opening and dosing intake or exhaust valves and controls open and close timing of intake or exhaust valves independently of the rotation of the crank shaft.
This device includes a timing sprocket which rotates with the crank shaft in a body, a housing which rotates with the timing sprocket in a body, a rotor which rotates relative to the housing and which operates the cam shaft and a vane which divides a fluid chamber formed between the rotor and the housing into an advance angle pressure chamber and a retard angle pressure chamber and which regulates the amount of the relative rotation between the rotor and the housing by the contact with end surfaces of a shoe portions formed on the housing. The vane is fitted into a vane groove which is formed on the rotor in the radial direction and rotates with the rotor in a body. Contacting portions are formed on the vane groove between a bottom portion and an opening end thereof and the rotational force is transmitted from the vane to the rotor through the contacting portions when the pressure difference is generated between the advance angle pressure chamber and the retard angle pressure chamber. A concave portion is formed on a radial inner end portion of the vane and a vane spring is disposed between the concave portion and the bottom portion the vane groove. The vane spring urges the vane outwardly in the radial direction so that a radial outer end of the vane slides on an inner wall of the fluid chamber.
In the above described device, however, a contacting area between the vane and a contacting portion of the vane groove is decreased by the concave portion of the valve. When the vane rotates with the rotor by the pressure difference between the advance angle pressure chamber and the retard angle pressure chamber, a driving force is applied to the vane due to the pressure difference and a load corresponding to the driving force is applied to the contacting portion of the vane groove. Further, when the vane regulates the relative rotation between the rotor and the housing by the contact with the end surfaces of the shoe portions, a reaction force is applied to the vane and a load corresponding to the reaction force is applied to the contacting portion of the vane groove. Therefore, in case that a radial length between the bottom portion of the vane groove and the radial inner end of the contacting portion is smaller than a radial length between the bottom portion of the vane groove and the concave portion, the surface pressure of the contacting portion increases and there is in danger that the contacting portions are worn.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to overcome the above drawback.
In order to achieve the foregoing object, the present invention provides a valve timing control device which includes a rotation member for opening and closing valves, a rotation transmitting member rotatably mounted on the rotation member, a fluid chamber defined between the rotation member and the rotation transmitting member, a vane fitted into a vane groove formed on the rotation member or the rotation transmitting member so as to divide the fluid chamber into a advance angle pressure chamber and a retard angle pressure chamber, the vane groove having contacting portions contacted with the vane and an elastic member dispose between the vane and the rotation member or the rotation transmitting member, wherein the radial length between the bottom portion of the vane groove and a bottom portion side end portion of the contacting portion is larger than a radial length been the bottom portion of the vane groove and an engaging portion of the vane engaged with the elastic member.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will be more apparent and more readily appreciated from the following detailed description of a preferred exemplary embodiment of the present invention, taken in connection with the accompanying drawings, in which;
FIG. 1
shows a sectional view of an embodiment of a valve timing control device in accordance with the present invention;
FIG. 2
shows a front view of the embodiment under the condition which a front plate is removed;
FIG. 3
shows an enlarged front view of a vane groove of the embodiment;
FIG. 4
shows an enlarged sectional view of the vane groove of the embodiment; and
FIG.
5
(
a
) and FIG.
5
(
b
) show diagrams of the mounting condition of the vane spring of the embodiment.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
Referring to FIG.
1
and
FIG. 2
, a valve timing control device includes a rotation member comprising a rotor
20
which is fixedly mounted on a top end portion of a cam shaft
10
rotatably supported on a cylinder head
100
of a combustion engine, a rotation transmitting member comprising a housing
30
mounted on the rotor
20
so as to be able to rotate relative to the rotor
20
within a predetermined angle, a front plate
40
, a rear plate
50
and a timing sprocket
31
integrally formed on the housing
30
, four vanes
70
mounted on the rotor
20
and a lock key
80
disposed in the housing
30
. The rotational torque is transmitted to the timing sprocket
31
via a crank sprocket and a timing chain (not shown) from a crank shaft (not shown) clockwise in FIG.
2
.
The cam shaft
10
includes cams which open and close intake or exhaust valves (not shown). An advance angle passage
11
and a retard angle passage
12
which extend in the axial direction are formed in the cam shaft
10
. The advance angle passage
11
is connected to a first connecting port
201
of a changeover valve
200
via a connection passage
16
. The retard angle passage
12
is connected to a second connecting port
202
of the changeover valve
200
via a connection passage
15
. The changeover valve
200
includes a well known structure in which a spool
204
is moved against a spring (not shown) by applying current to a solenoid
203
. When the changeover valve
200
is not excited, a supply port
206
connected to an oil pump
205
driven by the combustion engine is communicated to the second connecting port
202
and the first connecting port
201
is communicated to a drain port
207
. Further, when the changeover valve
200
is excited, as shown in
FIG. 1
, the supply port
206
is communicated to the first connecting port
201
and the second connecting port
202
is communicated to the drain port
207
. Thereby, the pressurized fluid from the oil pump
205
is supplied to the retard angle passage
12
when the changeover valve
200
is not excited and the pressurized fluid from the oil pump
205
is supplied to the advance angle passage
11
when the changeover valve
200
is excited.
The rotor
20
is fixed to the cam shaft
10
by a single bolt
91
and includes four vane grooves
21
, lock key groove
22
, four radial advance angle passages
23
, four radial retard angle passage
24
and a passage
25
which extends in the circumferential direction on the outer circumference of the rotor
20
. A head portion of the lock key
80
is fitted into the lock key groove
22
when the relative position between the rotor
20
and the housing
30
becomes a predetermined relative phase (most retard angle position) shown in FIG.
2
. The operation fluid is supplied to the lock key groove
22
from the advance angle passage
23
via the passage
25
. The vanes
70
are fitted into the vane grooves
21
so as to be able to move in the radial direction. Contacting portions
21
b
are formed on the vane groove
21
between a bottom portion
21
a
and an opening end thereof and the rotational force is transmitted from the vane
70
to the rotor
20
through the contacting portions
21
b
when the vanes
70
and the rotor
20
rotate relative to the housing
30
. A pair of projection portions
70
a
are formed on both axial ends of a bottom side end portion (a radial inner end portion) of each vane
70
and a concave portion
70
b
is formed between projection portions
70
a
, respectively. A flat plate shaped vane spring (elastic member)
73
is disposed between the bottom portion
70
a
and an engaging portion
70
c
formed on a bottom surface of the concave portion
70
b
, respectively. The vane springs
73
urge the vanes
70
outwardly in the radial direction so that a radial outer ends of the vanes
70
contact with the inner circumferential surface of the housing
30
. The projecting portions
70
a
prevent the vane springs
73
from contacting with the front plate
40
and the rear plate
50
.
As shown in FIG.
3
and
FIG. 4
, the radial length (A) between the bottom portion
21
a
of the vane groove
21
and a bottom portion side end portion
21
c
of the contacting portion
21
b
is larger than a radial length (B) between the bottom portion
21
a
of the vane groove
21
and the engaging portion
70
c
of the vane
70
. Thereby, since the contacting area between each vane
70
and rotor
20
can be increased, the surface pressure of the contacting portions
21
b
is decreased and the wear of the contacting portions
21
b
is prevented.
In this embodiment, the bottom portion
21
a
of the vane groove
21
has a flat surface shape. Thereby, the contact between the bottom portion
21
a
and the vane spring
73
becomes a line contact or a surface contact and the abrasion of the bottom portion
21
a
and the vane spring
73
can be prevented. Further, as shown in
FIG. 5
, in the mounting condition of the vane spring
73
, a mounting length H of the vane spring
73
(a radial length between the bottom portion
21
a
of the vane groove
21
and the engaging portion
70
c
) is smaller than a width L of the vane spring
73
. When the mounting length H is larger than the width L, the posture of the vane spring
73
at the mounting deteriorates, for example, the tumbling generates, and consequently it is not able to contact the radial outer ends of the vanes
70
to the inner circumference of the housing
30
with adequate load. In this embodiment, as mentioned above, since the mounting length H is set smaller than the width L, the load of the vane springs
73
can be stabilized.
The housing
30
is mounted on the outer circumference of the rotor
20
so as to be able to rotate relative to the rotor
20
within a predetermined angle. The circular front plate
40
and the circular rear plate
50
are fixed to both ends of the housing
30
by four bolts
92
. Four shoe portions
33
are formed on the inner circumference of the housing
30
. The inner circumferential surface of the shoe portions
33
contact with the outer circumferential surface of the rotor
20
so as to be able to slide in the circumferential direction. Thereby, the housing
30
is rotatably supported on the housing
30
. In one of the shoe portions
33
, a lock key refuging groove
34
in which the lock key
80
is disposed and a groove
35
in which a spring
81
urging the lock-key
80
in the radial direction is disposed and which communicates to the refuging groove
34
are formed.
A torsion spring
60
is disposed between the rotor
20
and the housing
30
. On end of the torsion spring
60
is engaged with the front plate
40
and the other end thereof is engaged with the rotor
20
. The torsion spring
60
urges always the rotor
20
toward the advance angle direction relative to the housing
30
, the front plate
40
and the rear plate
50
and improves the response of the operation of the rotor
20
toward the advance angle direction.
Four fluid chambers R
0
are formed by the rotor
20
, the housing
30
, the front plate
40
and the rear plate
50
. Each vane
70
divides the fluid chamber R
0
into a advance angle pressure chamber R
1
and a retard angle pressure chamber R
2
, respectively. The amount of the relative rotation between the rotor
20
and the housing
30
depends on the circumferential width (angle) of the fluid chamber R
0
. At the most advance angle position, the vane
70
A contacts with a circumferential surface of the shoe portion
33
A and the rotation of the rotor
20
relative to the housing
30
in the advance angle direction is restricted. At the most retard angle position, the vane
70
B contacts with a circumferential surface of the shoe portion
33
B and the rotation of the rotor
20
relative to the housing
30
in the retard angle direction is restricted. At the most retard angle position, the head portion of the lock key
80
is fitted into the lock key groove
22
as shown in FIG.
2
and the relative rotation between the rotor
20
and the housing
30
is locked.
The operation of the valve timing control device having the above structure will now be described. When the duty ratio of current applied to the solenoid
203
of the changeover valve
200
is increased and the position of the spool
204
is changed, the operational fluid (hydraulic pressure) supplied from the oil pump
205
is supplied to the advance angle pressure chambers R
1
via the supply port
206
, the connecting port
201
, the connecting passage
16
, the advance angle passage
11
and passage
23
. Further, the operational fluid (hydraulic pressure) supplied from the oil pump
205
is supplied from the passage
23
to the lock key groove
22
. On the other hand, the operational fluid (hydraulic pressure) in the retard angle pressure chambers R
2
is discharged from the drain port
207
of the changeover valve
200
via the passage
24
, the retard angle passage
12
, the connecting passage
15
and the connecting port
202
. In this time, the lock key
80
moves against the spring
81
and the head portion thereof comes off from the lock key groove
22
. Thereby, the lock condition between the rotor
20
and the housing
30
is released. Further, the rotor
20
and each vane
70
are rotated relative to the housing
30
and the plates
40
,
50
toward the advance angle direction (clockwise).
In the condition which the lock key
80
comes off from the lock key groove
22
, when the duty ratio of current applied to the solenoid
203
of the changeover valve
200
is decreased, the operation fluid can be supplied to the retard angle pressure chambers R
2
and the operational fluid In the advance angle pressure chambers R
1
can be discharged. Accordingly, it is able to adjust continuously the position of the rotor
20
and each vane
70
relative to the housing
30
and the plates
40
,
50
toward any position between the most advance angle position and the most retard angle position shown in FIG.
2
.
As mentioned above, according to the present Invention, since the contacting area between each vane and rotor can be increased, the surface pressure of the contacting portions is decreased and the wear of the contacting portions is prevented. Further, since the leak of the fluid via a clearance between the vane groove and the vane is decreased by the enlargement of the contacting area, the invasion of the hard particle in the fluid into the clearance is prevented and the wear of the vanes and vane grooves is prevented.
Claims
- 1. A valve timing control device comprising:a rotation member for opening and closing valves, a rotation transmitting member rotatably mounted on the rotation member, a fluid chamber defined between the rotation member and the rotation transmitting member, a vane fitted into a vane groove formed on the rotation member or the rotation transmitting member so as to divide the fluid chamber into a advance angle pressure chamber and a retard angle pressure chamber, the vane groove having contacting portions contacted with the vane and an elastic member disposed between the vane and the rotation member or the rotation transmitting member, wherein the radial length between the bottom portion of the vane groove and a bottom portion side end portion of the contacting portion is larger than a radial length between the bottom portion of the vane groove and an engaging portion of the vane engaged with the elastic member.
- 2. A valve timing control device as recited in claim 1, wherein a pair of projection portions are formed on both axial ends of a bottom side end portion of each vane and a concave portion is formed between the projection portions, and the engaging portion is formed on a bottom of the concave portion.
- 3. A valve timing control device as recited in claim 2, wherein the bottom portion of the vane groove has a flat surface shape.
- 4. A valve timing control device as recited in claim 3, wherein a radial length between the bottom portion of the vane groove and the engaging portion is smaller than a width of the vane spring.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2002-249249 |
Aug 2002 |
JP |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
5937810 |
Sato et al. |
Aug 1999 |
A |
6039015 |
Sato |
Mar 2000 |
A |
6053138 |
Trzmiel et al. |
Apr 2000 |
A |
6173686 |
Nakayoshi et al. |
Jan 2001 |
B1 |
Foreign Referenced Citations (1)
Number |
Date |
Country |
11-101107 |
Sep 1997 |
JP |