Information
-
Patent Grant
-
6334414
-
Patent Number
6,334,414
-
Date Filed
Thursday, August 3, 200023 years ago
-
Date Issued
Tuesday, January 1, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Corrigan; Jaime
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 9012
- 123 9015
- 123 9017
- 123 9031
- 074 568 R
- 464 1
- 464 2
- 464 160
-
International Classifications
-
Abstract
A valve timing adjusting apparatus is designed for quickly starting an engine at the intermediate position between the most retarded angle and the most advanced angle and for preventing hammering sound. A top end surface of a stopper piston receives a retard hydraulic pressure, and an annular surface of a large diameter sliding portion receives the retard hydraulic pressure from a hydraulic chamber. The retard hydraulic pressure applied to the top end surface and the annular surface acts in the direction to pull out the stopper piston from a fitting bore. An annular surface of the large diameter sliding portion receives an advance hydraulic pressure when an advance hydraulic chamber is communicated to a hydraulic chamber. The hydraulic pressure of the hydraulic chamber acts as a force for pushing the stopper piston in a fitting member. When the through hole is closed by the large diameter sliding portion, the hydraulic chamber acts as a damper chamber.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application relates to and incorporates herein by reference Japanese Patent Applications No. 11-223974 and No. 11-223987, both being filed on Aug. 6, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a valve timing adjusting apparatus for changing the operation timing (valve timing) of a suction valve and/or an exhaust valve of an internal combustion engine.
2. Related Art
In a vane type valve timing adjusting apparatus, a camshaft is driven by means of a timing pulley, a chain sprocket, or the like that is rotated synchronously with a crankshaft of an engine. Thus, the valve timing of a suction valve and/or an exhaust valve is hydraulically controlled based on the phase difference of relative rotation between the timing pulley or chain sprocket and a camshaft.
In the case of such a vane type valve timing apparatus that uses working fluid, a load torque that fluctuates between positive side and negative side that is caused by driving the suction valve and/or the exhaust valve is exerted on the camshaft. For example, in the state that the working fluid is not supplied sufficiently as in the engine cranking at the starting of an engine, a vane member swings toward a housing member that accommodates the vane member, and generates hammering sound due to collision between the housing member and the vane member.
It is therefore proposed that a stopper piston fits a housing member when a camshaft is positioned intermediate between the most retarded angle and the most advanced angle with respect to the crankshaft to control the relative rotation of the camshaft with respect to the crankshaft. The engine is started with the camshaft being at the intermediate position between the most retarded angle and the most advanced angle. That is, the engine is thereby started in the state that the camshaft is located at the preferable position with respect to the crankshaft.
However, a force exerted on the stopper piston to be fitted with an fitting bore is only the urging force of a spring, it is difficult to fit the stopper piston in the fitting bore within a short time. Furthermore, in the case that a hydraulic pressure for maintaining the unrestricted state in which a contact portion is disengaged from the fitting bore is low, the stopper piston jumps out to the fitting bore side due to the urging force of the spring during the phase control for rotating the vane member relatively to the housing member. As a result the stopper piston can be caught in the fitting bore.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a valve timing adjusting apparatus for enabling an engine starting promptly while minimizing hammering sound.
It is another object of the present invention to provide a valve timing adjusting apparatus for preventing a constraint member from being constrained during a phase control.
According to a valve timing adjusting apparatus of the present invention, a constraint member is provided for constraining the relative rotation of a driven side rotor with respect to a driving side rotor when the driven side rotor is positioned at the intermediate position between the most retarded angle and the most advanced angle with respect to the driving side rotor is provided. By constraining the relative rotation of the driven side rotor with respect to the driving side rotor at the intermediate position, failure in starting an engine is reduced thus minimizing noxious exhaust gas.
In addition to release of constraint state associated with a contact portion and a contact receiving portion by means of the first working fluid pressure, the contact portion is displaced in the direction to be brought into contact with the contact receiving portion by means of the second working fluid pressure. For example, the first working fluid pressure that acts on the contact portion is reduced and the second working fluid pressure is increased when the engine is to be stopped. As a result, the contact portion is surely brought into contact with the contact receiving portion at the intermediate position. Thereby, the engine is surely started in a short time.
Furthermore, by reducing the first working fluid pressure that acts on the contact portion and by increasing the second working fluid pressure when the engine is to be started, the contact portion is held in contact with the contacted portion at the intermediate position. Because the intermediate phase can be held during cranking when the engine is to be started, the engine can be started surely in a short time.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
FIG. 1
is a cross sectional view showing an entirety of a valve timing adjusting apparatus according to a first embodiment of the present invention;
FIG. 2
is another cross sectional view showing the entirety of the valve timing adjusting apparatus according to the first embodiment;
FIGS. 3A
to
3
C are partial cross sectional views taken along the line III—III of FIG.
2
and showing the position of a stopper piston in the first embodiment;
FIG. 4
is a cross sectional view showing the position of a vane rotor located at the most advanced position in the first embodiment;
FIG. 5
is a cross sectional view taken along the line I-O-V of
FIG. 2
;
FIGS. 6A and 6B
are cross sectional views showing position of a stopper piston and shape of a fitting member, respectively, in a second embodiment of the present invention;
FIGS. 7A
to
7
C are partial cross sectional views taken along the line VII—VII of FIG.
8
and showing the position of a stopper piston in a third embodiment of the present invention;
FIG. 8
is a cross sectional view showing an entirety of a valve timing adjusting apparatus according to the third embodiment;
FIG. 9
is a cross sectional view showing the state that a vane rotor is positioned at the most advanced position in the third embodiment;
FIG. 10
is a cross sectional view taken along X-O-X of
FIG. 8
;
FIG. 11
is a cross sectional view taken along the line X-O-XI of
FIG. 8
;
FIGS. 12A and 12B
are cross sectional views showing position of a stopper piston in a fourth embodiment of the present invention; and
FIG. 13
is a cross sectional view showing shape of a fitting member in the fourth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in detail with reference to various embodiments, in which the same or like parts are designated with the same or like reference numerals.
(First Embodiment)
Referring first to
FIG. 1
, a valve timing adjusting apparatus
1
is of a hydraulic pressure control type for controlling the valve timing of a suction valve of an internal combustion engine (not shown).
A chain sprocket
10
that serves as one side wall of a driven side rotor is coupled with a crankshaft (not shown) that serves as a driving shaft of the engine by means of a chain (not shown) to transmit driving force from the crankshaft. It rotates synchronously with the crankshaft. A camshaft
2
that serves as a driven shaft receives a driving force from the chain sprocket
10
to operate a suction valve (not shown). The camshaft
2
is capable of rotating with a predetermined phase difference with respect to the chain sprocket
10
, that is, crankshaft. The chain sprocket
10
and the camshaft
2
rotate clockwise when viewed in the direction of arrow X in FIG.
1
. This rotation direction is referred to as the advance direction.
A thin plate-like intermediate plate
17
is disposed between the chain sprocket
10
and a shoe housing
12
. The intermediate plate
17
prevents working fluid from leaking between the chain sprocket
10
and the shoe housing
12
. The chain sprocket
10
, the shoe housing
12
, and the intermediate plate
17
provide a housing member that serves as a driving side rotor, and are fixed one another with bolts
20
coaxially. The shoe housing
12
comprises a cylindrical peripheral wall
13
and a front plate
14
that serves as the other side wall of the housing member and formed into a single piece.
As shown in
FIG. 2
, the shoe housing
12
has a plurality of shoes
12
a,
12
b
and
12
c
that are formed in the shape of trapezoid with approximately the same angular interval in the circumferential direction. Three fan-shaped accommodation chambers
50
are provided for accommodating vanes
15
a,
15
b
and
15
c
that serve as vane members respectively among the shoes
12
a,
12
b
and
12
c
in the peripheral direction. The cross section of the inner peripheral surface of the shoes
12
a,
12
b
and
12
c
is formed in the shape of arc.
The vane rotor
15
that serves as a driven side rotor has three vanes
15
a,
15
b
and
15
c
with approximately the same angular interval in the circumferential direction. The vanes
15
a,
15
b
and
15
c
are accommodated to be capable of rotating in respective accommodation chambers
50
. Each vane divides each accommodation chamber
50
into a retard hydraulic chamber
54
,
55
,
56
, and an advance hydraulic chamber
51
,
52
,
53
. The arrow for indicating the retard direction and advance direction in
FIG. 2
represents the retard direction and advance direction of the vane rotor
15
with respect to the shoe housing
12
.
As shown in
FIG. 1
, the vane rotor
15
and a bushing
22
are fixed to the camshaft
2
with a bolt
21
into a single piece and provide a driven side rotor. A pin
23
is provided for positioning the vane rotor
15
with respect to the camshaft
2
in the rotation direction.
The camshaft
2
and bushing
22
are fitted in the inner peripheral wall
10
a
of the chain sprocket
10
and the inner peripheral wall
14
a
of the front plate
14
relatively capable of rotating. Therefore, the camshaft
2
and vane rotor
15
are relatively capable of rotating coaxially with respect to the chain sprocket
10
and the shoe housing
12
. The inner peripheral wall
10
a
of the chain sprocket
10
and the inner peripheral wall
14
a
of the front plate
14
provide a bearing member of the driven side rotor.
A spring
24
that serves as advance urging means is accommodated in a cylindrical recess
11
formed on the chain sprocket
10
. The one end of the spring
24
is engaged with a fitting bore
11
a
of the recess
11
, and the other end is engaged with the vane rotor
15
through a slotted hole
17
a
formed on the intermediate plate
17
.
The load that occurs when the camshaft
2
drives the suction valve fluctuates between positive side and negative side. Herein the positive direction of the load torque represents the retard direction of the vane rotor
15
with respect to the shoe housing
12
, and the negative direction of the load torque represents the advance direction of the vane rotor
15
with respect to the shoe housing
12
. The load torque is exerted in the positive direction, that is, retard direction in average. The urging force of the spring
24
is exerted as a torque so that the vane rotor
15
is rotated in the advance side with respect to the shoe housing
12
. The magnitude of the torque in the advance direction exerted on the vane rotor
15
by the spring is approximately the same as the average load torque applied to the camshaft
2
.
Sealing members
26
are fitted on the outer peripheral wall of the vane rotor
15
as shown in
FIG. 2. A
small clearance is formed between the outer peripheral wall of the vane rotor
15
and the inner peripheral wall of the peripheral wall
13
. Each sealing member
26
prevents leakage of working fluid between the hydraulic chambers
50
through the clearance. The sealing member
26
is pressed against the peripheral wall
13
by means of the urging force of a plate spring
27
shown in FIG.
1
.
Guide rings
30
and
31
are press-fitted and held in the inner wall of the vane
15
a
that forms an accommodation hole
38
, and a cylindrical stopper piston
32
that serves as a contact member is accommodated in the guide rings
30
and
31
capable of sliding in the rotation axis direction of the camshaft
2
. A fitting member
40
that serves as a contacted member shown in
FIG. 1
having a circular cross section is press-fitted and held in a recess
14
b
formed on the front plate
14
. On the fitting member
40
, a fitting bore
41
with which the stopper piston
32
is in contact and capable of fitting is formed, and an enlarged bore
43
is formed. The enlarged bore
43
has the retard side end surface on the same plane as that of the retard side end surface of the fitting bore
41
. The bore
43
is shallower than the fitting bore
41
and extends to the advance side.
As shown in
FIGS. 3A
to
3
C, a tapered top end
33
of stopper piston
32
has the diameter that decreases toward the fitting direction, and the fitting bore
41
is also tapered at approximately the same angle as that of the inclination of the top end
33
. Therefore, the stopper piston
32
is fitted in the fitting bore
41
smoothly. Furthermore, because the fitting bore
41
is fitted with the stopper piston
32
without excessive play, generation of hammering sound due to fluctuation of the load torque is minimized. Furthermore, because the contact area of the top end
33
that is in contact with the fitting bore
41
is large, the stress applied to the top end
33
is reduced, and the life of the stopper piston
32
is extended.
A spring
37
that serves as contact urging means urges the stopper piston
32
against the fitting member
40
. The stopper piston
32
, the fitting member
40
and the spring
37
provide constraint means. Furthermore, the stopper piston
32
and the fitting member
40
provide regulation means.
The stopper piston
32
that is cylindrical having a bottom comprises the top end
33
, a large diameter sliding portion
34
and a small diameter sliding portion
35
located in the order from the front plate
14
side. A ring taper surface
33
a
is formed on the outer periphery of the top end
33
. The angle of the taper surface
33
a
is approximately the same as the taper angle of the fitting bore
41
.
The retard hydraulic pressure that acts as the first working fluid pressure is applied to the top end surface
33
b
that serves as the first pressure receiving portion formed on the top end
33
from a hydraulic chamber
42
, and the retard hydraulic pressure is also applied to the annular surface
34
a
that serves as the third pressure receiving portion formed on the fitting bore side of the larger diameter sliding portion
34
from a hydraulic chamber
45
. The retard hydraulic pressure that is applied to the top end surface
33
b
and the annular surface
34
a
acts in the direction to push out the stopper piston
32
from the fitting bore
41
.
The annular surface
34
b
formed on the side opposite to the fitting bore side of the large diameter sliding portion
34
as the second pressure receiving portion receives the advance hydraulic pressure as the second working fluid pressure from a hydraulic chamber
46
that communicates to an advance hydraulic chamber
54
through a fluid passage
48
and a through hole
30
b
in the state that the stopper piston
32
is fitted in the fitting bore
41
or the enlarged bore
43
, that is, in the constraint state as shown in FIG.
3
A and FIG.
3
B.
In FIG.
3
A and
FIG. 3B
, the hydraulic pressure of the hydraulic chamber
46
acts in the direction to fit the stopper piston
32
in the fitting bore
41
. As shown in
FIG. 3C
, when the stopper piston
32
is pushed out from the enlarged bore
43
, that is, at the boundary position between unconstraint state and constraint state associated with the stopper piston
32
and the fitting member
40
, the through hole
30
b
that serves as the second working fluid passage is closed by the large diameter sliding portion
34
. Thus, the communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down. At this time, the hydraulic pressure of the hydraulic chamber
46
is equalized to the atmospheric pressure, and does not act to push the stopper piston
32
toward the fitting member
40
.
The accommodation hole
38
of the side opposite to the fitting member side of the stopper piston
32
is open to the atmosphere through the slotted hole
17
a
formed on the intermediate plate
17
and a fluid passage
10
b
formed on the chain sprocket
10
not only when the vane rotor
15
is located within the relative rotation angle range, that is, at the most advanced position with respect to the shoe housing
12
as shown in
FIG. 4
but also when the vane rotor is located at the most retarded position. Therefore, the hydraulic pressure of the working fluid that leaked from the sliding clearance between the small diameter sliding portion
35
and the guide ring
31
to the accommodation hole
38
of the side opposite to the fitting member side of the stopper piston
32
is approximately equal to the atmospheric pressure. Therefore, the working fluid that leaked to the accommodation hole
38
of the side opposite to the fitting member side of the stopper piston
32
does not act as the force to push the stopper piston
32
toward the fitting member
32
.
Sliding portions of the stopper piston
32
slide on the inner peripheral wall of the guide ring
30
or guide ring
31
. The top end
33
of the stopper piston
32
can be fitted in the fitting bore
41
when the vane rotor
15
is positioned at the intermediate position between the most retarded position and the most advanced position with respect to the shoe housing
12
as shown in FIG.
2
.
In the state that the stopper piston
32
is fitted in the fitting bore
41
, the relative rotation of the vane rotor
15
with respect to the shoe housing
12
is constrained. As shown in
FIG. 3A
, when the stopper piston
32
is fitted in the fitting bore
41
, the intermediate position where the relative rotation between the shoe housing
12
and the vane rotor
15
is the position that sets the optimal phase difference between the crankshaft and the camshaft
2
, that is, the optimal valve timing of the suction valve that enables the starting of the engine surely.
When the vane rotor
15
is rotated to the retard side with respect to the shoe housing
12
from the state shown in
FIG. 3C
, the circumferential position of the stopper piston
32
deviates from that of the fitting bore
41
. It becomes impossible that the stopper piston
32
is fitted in the fitting bore
41
. When the vane rotor
15
is rotated up to the most advanced angle from the intermediate position with respect to the shoe housing
12
, the stopper piston
32
locates on the enlarged bore
43
as shown in FIG.
3
B.
A fluid passage
44
formed on the front plate
14
communicates between a retard hydraulic chamber
51
and the hydraulic chamber
42
. A through hole
30
a
that passes through the guide ring
30
is formed on the guide ring
30
. A fluid passage
47
and the through hole
30
a
communicate between the retard hydraulic chamber
51
and the hydraulic chamber
45
. The through hole
30
b
formed on the guide ring
30
can communicate between the hydraulic chamber
46
and the fluid passage
48
.
As shown in
FIG. 2
, the retard hydraulic chamber
51
is formed between the shoe
12
a
and the vane
15
a.
The retard hydraulic chamber
52
is formed between the shoe
12
b
and the vane
15
b.
The retard hydraulic chamber
53
is formed between the shoe
12
c
and the vane
15
c.
Furthermore, the advance hydraulic chamber
54
is formed between the shoe
12
c
and the vane
15
a.
The advance hydraulic chamber
55
is formed between the shoe
12
a
and the vane
15
b.
The advance hydraulic chamber
56
is formed between the shoe
12
b
and the vane
15
c.
The retard hydraulic chamber
51
communicates to a fluid passage
61
. The retard hydraulic chambers
52
and
53
communicate to a fluid passage
60
formed in C-shape on the camshaft side end surface of the boss portion
15
d
shown in FIG.
2
through oil passages
62
and
63
. Furthermore, the retard hydraulic chambers
51
,
52
and
53
communicate to a fluid passage
200
formed on the camshaft
2
shown in FIG.
1
through the fluid passages
60
and
61
.
As shown in
FIG. 2
, the advance hydraulic chamber
55
communicates to a fluid passage
72
. The advance hydraulic chambers
54
and
56
communicate to a fluid passage
70
formed in C-shape on the bushing side end surface of the boss
15
d
through oil passages
71
and
73
. Furthermore, the advance hydraulic chambers
54
,
55
and
56
communicate to a fluid passage
201
formed on the camshaft shown in
FIG. 1 through a
fluid passage (not shown) formed in the axial direction of the boss portion
15
d
from the fluid passages
70
and
72
.
The fluid passage
200
communicates to a groove passage
202
formed on the outer peripheral wall of the camshaft
2
. The fluid passage
201
communicates to a groove passage
203
formed on the outer peripheral wall of the camshaft
2
. The groove passage
202
is connected to a switching valve
212
through a fluid passage
204
. The groove passage
203
is connected to the switching valve
212
through a fluid passage
205
. An oil supply passage
206
that serves as a working fluid supply passage is connected to a fluid pump
210
. An oil drain passage
207
that serves as a working fluid discharging passage is open to a drain
211
. The oil pump
210
pumps up working fluid from the drain and supplies it to hydraulic chambers through the switching valve
212
. The switching valve
212
is a well known 4-port guide valve.
A valve member
213
of the switching valve
212
is urged in one direction by a spring
214
, and reciprocated by controlling a current supplied to a solenoid
215
. The current supplied to the solenoid
215
is controlled by an engine control unit (ECU)
300
. The ECU
300
receives the detection signals from various sensors and transmits the signal to components of the engine. By reciprocating the valve member
213
, the combination of communication and shutdown between the fluid passages
204
and
205
, the oil supply passage
206
and the oil drain passage
207
is switched. The above oil passage structure allows working fluid to be supplied from the oil pump
210
to the retard hydraulic chambers
51
,
52
and
53
, or the advance hydraulic chambers
54
,
55
and
56
, and the hydraulic chambers
42
,
45
and
46
. It also allows the working fluid to be drained from oil pressure chambers to the drain
211
.
In operation, when an ignition is turned off to stop the engine, a valve position
213
a
is selected because the ECU
300
turns off a current supplied to the solenoid
215
. Then, working fluid is supplied to the advance hydraulic chambers, and the retard hydraulic chambers. The hydraulic chambers
42
and
45
are opened to the drain. Thereby, the vane rotor
15
is rotated to the advance side with respect to the shoe housing
12
.
At this time, when the stopper piston
32
is separated from the fitting member
40
far from the position as shown in
FIG. 3C
, that is, when the stopper piston
32
is in unconstraint from the fitting bore
41
and the enlarged bore
43
, the communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down by the large diameter sliding portion
34
. Therefore, the hydraulic pressure of the hydraulic chamber
46
does not act to push the stopper piston
32
toward the fitting member
40
. However, because the hydraulic pressure in the hydraulic chambers
42
and
45
decrease, the urging force of the spring
37
pushes the stopper piston
32
to move toward the fitting member
40
.
When an engine stop is indicated in the state that the vane rotor
15
is positioned with deviation to the retard side with respect to the shoe housing
12
from the intermediate position (constraint position) where the stopper piston
32
is fitted in the fitting bore
41
, the working fluid is supplied to the advance hydraulic chambers to thereby rotate the vane rotor
15
to the advance side. The stopper piston
32
is moved toward the fitting member
40
by means of the urging force of the spring
37
, and the unconstraint state changes to the constraint state. At this time, the large diameter sliding portion
34
releases the closed through hole
30
b,
and the through hole
30
b
begins to open.
Then, the hydraulic chamber
46
becomes communicative to the advance hydraulic chamber
54
through the through hole
30
b,
and the working fluid is supplied from the advance hydraulic chamber
54
to the hydraulic chamber
46
. Therefore, the hydraulic pressure of the hydraulic chamber
46
acts as a pushing force that pushes the stopper piston
32
toward the fitting member
40
.
When the vane rotor
15
reaches the intermediate position (constraint position) shown in
FIG. 3A
with respect to the shoe housing
12
, the stopper piston
32
is fitted in the fitting bore
41
by means of the urging force of the spring
37
and a force supplied from the hydraulic chamber
46
. If the stopper piston
32
cannot be fitted in the fitting bore
41
, the vane rotor
15
is rotated toward the advance side beyond the intermediate position and fitted with the enlarged bore
43
.
When an engine stop is instructed in the state that the vane rotor
15
is positioned at the advance side with respect to the shoe housing
12
with deviation from the intermediate position where the stopper piston
32
is to be fitted in the fitting bore
41
, the vane rotor
15
is rotated to the advance side and the stopper piston
32
is resultantly fitted in the enlarged bore
43
.
When the stopper piston
32
is fitted in the fitting bore
41
before starting of the engine, the phase difference of the vane rotor
15
with respect to the shoe housing
12
, that is, the phase difference of the camshaft
2
with respect to the crankshaft is maintained at the most preferable position for starting the engine. Thus, the engine can be started surely within a short time.
It is assumed here that the engine is started in the state that the stopper piston
32
is not fitted in the fitting bore
41
before the engine is started and the camshaft
2
is positioned at the advance side from the intermediate position with respect to the crankshaft. In this instance, the stopper piston
32
is fitted in the enlarged bore
43
. Because the advance torque applied to the vane rotor
15
and the camshaft
2
by the spring
24
is approximately equal to the averaged load torque, the maximum value of the load torque exerted in the retard direction of the positive side is larger than the urging force of the spring
24
. The vane rotor
15
swings to the retard side with respect to the shoe housing
12
against the urging force of the spring
24
that is exerted in the advance direction with changing of the load torque.
The vane rotor
15
is stopped on the retard side surface of the enlarged bore
43
at the intermediate position. The working fluid is not introduced into the hydraulic chambers
42
and
45
during cranking when the engine is to be started. When the stopper piston
32
reaches the intermediate position, the stopper piston
32
is fitted in the fitting bore
41
by means of the urging force of the spring
37
and the force received from the hydraulic chamber
46
.
The stopper piston
32
is fitted in the enlarged bore
43
even when the stopper piston
32
is not fitted in the fitting bore
41
before the engine is started. When the engine is started, the stopper piston
32
is fitted in the fitting bore
41
quickly, and the camshaft
2
is held at the intermediate position with respect to the crankshaft. As a result, the engine is started surely in a short time.
Because the valve position
213
a
of the switching valve
212
is selected during cranking when the engine is to be started, the working fluid is supplied to the advance hydraulic chambers and the hydraulic chamber
46
, and the retard hydraulic chambers and the hydraulic chamber
42
are opened to the drain. Therefore, the stopper piston
32
will not be pulled out from the fitting bore
41
or the enlarged bore
43
.
After the engine is started, the working fluid is charged to the retard hydraulic chambers and the hydraulic pressure of the hydraulic chambers
42
and
45
increases up to a predetermined pressure. Then, the stopper piston
32
is pulled out from the fitting bore
41
. The relative rotation of the vane rotor
15
with respect to the shoe housing
12
, that is, the phase control becomes possible. When the stopper piston
32
moves from the fitting bore
41
in the unconstraint direction shown in
FIG. 3C
, the through hole
30
b
is closed by the large diameter sliding portion
34
. The communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down. The hydraulic chamber
46
is almost sealed.
The hydraulic pressure of the working fluid increases to a sufficient value after the engine is started. Then, either one of the valve portions
213
a,
213
b
and
213
c
of the valve member
213
is selected depending on the instruction given by the ECU
300
. Thereby, the supply of the working fluid to the hydraulic chambers and drain of the working fluid from the hydraulic chambers are controlled. The relative rotation of the vane rotor
15
with respect to the shoe housing
12
is controlled.
While the engine is being operated normally, the stopper piston
32
is kept at the position far from the position where the stopper piston
32
is just pulled out as shown in FIG.
3
C. Therefore, the hydraulic chamber
46
is almost sealed as described above. Even though the hydraulic pressure of the hydraulic chambers
42
and
45
decrease so that the stopper piston
32
is to be moved toward the fitting member
40
, the hydraulic pressure
46
acts as a damper chamber and the moving speed is reduced.
Therefore, even though the stopper piston
32
is to be moved toward the fitting member
40
due to reduction of the hydraulic pressure when the stopper piston
32
passes on the fitting member
40
concomitantly with the relative rotation of the vane rotor
15
with respect to the shoe housing
12
, the hydraulic chamber
46
acts as a damper chamber and the stopper piston
32
passes on the fitting member
40
without fitting with the fitting member
40
, and thus the stopper piston
32
is prevented from being fitted with the fitting member
40
.
The first working fluid pressure is assigned to the retard side and the second working fluid pressure is assigned to the advance side. The advance pressure is increased when the engine is to be stopped to thereby help the fitting of the stopper piston
32
for stopping.
(Second Embodiment)
In a second embodiment shown in
FIG. 6A
, the stopper piston
32
is provided with only one pressure receiving portion for receiving the retard hydraulic pressure as the first pressure receiving portion at the top end surface
32
a
of the top end. The second pressure receiving portion for receiving the advance hydraulic pressure is formed as an annular surface of the top end on the side opposite to the fitting member
40
.
When the stopper piston
32
is pulled out entirely from the fitting bore
41
and the enlarged bore
43
and brought into the unconstraint state, a through hole
30
b
is closed by the top end. Thereby, the communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down, and the hydraulic chamber
46
acts as a damper chamber.
The taper angle θ of the top end is formed to be 15 degrees or less. Because the taper angle θ is sharp, a frictional force that overcomes the load torque that the camshaft
2
receives is generated in the space of the fitting bore
41
formed on the fitting member
40
by means of the force received from the spring
37
and the advance hydraulic pressure of the hydraulic chamber
46
. As a result, the stopper piston
32
is kept fitted in the fitting bore
41
. Furthermore, the variation of the fitting depth of the stopper piston
32
that is fitted in the fitting bore
41
is reduced.
The fitting bore
41
formed on the fitting member
40
is a slotted hole that extends in the rotation direction of the stopper piston
32
, that is, in the direction perpendicular to the rotation direction of the vane rotor
15
as shown in FIG.
6
B. In detail, the diameter D
2
of the fitting bore
41
in the direction perpendicular to the rotation direction is larger than the diameter D
1
of the fitting bore
41
in the rotation direction.
Even if the fitting bore
41
or stopper piston
32
has some manufacturing allowance in the direction perpendicular to the rotation direction, the stopper piston
32
can be fitted in the fitting bore
41
. The limitation on the manufacturing allowance can be mitigated. As a result, the manufacturing becomes easy and the manufacturing cost is reduced.
In the first and second embodiments, the retard hydraulic pressure is applied to the stopper piston in the direction to pull out the stopper piston from the fitting bore and the enlarged bore, and the advance hydraulic pressure is applied to the stopper piston in the direction to push the stopper piston in the fitting member. Therefore, the retard hydraulic chamber is opened to the drain and the working fluid is supplied to the advance hydraulic chamber when an engine stop is instructed. The stopper piston can be thereby fitted surely in the fitting bore at the intermediate position. Because the engine is started in the state that the vane rotor is held at the intermediate position with respect to the shoe housing, the engine can be started surely in a short time.
In addition to the constraint means for constraining the vane rotor at the intermediate position with respect to the shoe housing by fitting the stopper piston in the fitting bore, the enlarged bore serving as regulation means for preventing the vane rotor from rotating from the intermediate position toward the retard side and for allowing the vane rotor to rotate toward the advance side is formed. Therefore, the stopper piston is fitted in the enlarged bore and stopped at the retard side of the enlarged bore, and the stopper piston is thereby fitted surely with the fitting bore. As a result, the engine is stopped in the state that the vane rotor is held at the intermediate position with respect to the shoe housing, which position is most suitable for engine starting. Therefore, the engine can be started surely in a short time.
Because the through holes
30
b
and
30
b
that communicate between the hydraulic chamber
46
and the advance hydraulic chamber
54
are closed/opened by displacing the stopper piston, the through holes
30
b
and
30
b
are surely opened/closed by displacing the stopper piston
32
. Furthermore, because other opening/closing valves and switching valves are not needed for opening/closing the second working fluid passage that communicates between the hydraulic chamber
46
and the advance hydraulic chamber
54
, the number of necessary parts is reduced, the assembling work becomes simple, and the manufacturing cost is reduced.
(Third Embodiment)
In a third embodiment shown in
FIGS. 7A-7C
to
11
, the top end surface
33
b
that serves as the first pressure receiving portion formed on the top end
33
receives the retard hydraulic pressure that serves as the first working fluid pressure from the hydraulic chamber
42
. The annular surface
34
a
that serves as the second pressure receiving portion formed on the fitting bore side of the large diameter sliding portion
34
receives the advance hydraulic pressure from the hydraulic chamber
45
and the retard hydraulic pressure exerted on the top end surface
33
b.
The advance hydraulic pressure exerted on the annular surface
34
a
act in the direction to pull out the stopper piston
32
from the fitting bore
41
. The hydraulic chamber
42
communicates to the retard hydraulic chamber
51
through the fluid passage
44
formed on the front plate
14
. The hydraulic chamber
45
communicates to the advance hydraulic chamber
54
through the fluid passage
47
formed on the vane
15
a
and the through hole
30
a
formed on the guide ring
30
.
The fluid passage
47
and the through hole
30
a
provide the second pressure receiving passage. The pressure receiving area of the top end surface
33
b
is larger than the pressure receiving area of the annular surface
34
a
and the annular surface
34
b
that serves as the third pressure receiving portion that will be described hereinafter. Furthermore, the pressure receiving area of the annular surface
34
a
is larger than the pressure receiving area of the annular surface
34
b.
The annular surface
34
b
that serves as the third pressure receiving portion formed on the side opposite to the fitting bore side of the large diameter sliding portion
34
receives the advance hydraulic pressure that serves as the second working fluid pressure from the hydraulic chamber
46
. The hydraulic chamber
46
communicates to the advance hydraulic chamber
54
through the fluid passage
48
formed on the vane
15
a
and the through hole
30
b
formed on the guide ring
30
. The fluid passage
48
and the through hole
30
b
provide the third pressure receiving passage.
As shown in
FIG. 7A
, in the state that the stopper piston
32
is fitted in the fitting bore
41
, the through hole
30
a
is closed by the large diameter sliding portion
34
. Then, because the working fluid in the advance hydraulic chamber
54
is not supplied to the hydraulic chamber
45
, the hydraulic pressure of the hydraulic chamber
45
does not act in the direction to pull out the stopper piston
32
from the fitting bore
41
.
Furthermore, as shown in
FIG. 7C
, when the stopper piston
32
is pulled out from the enlarged bore
43
, that is, at the boundary position between the unconstraint state and the constraint state associated with the stopper piston
32
and the fitting member
40
, the through hole
30
b
is closed by the large diameter sliding portion
34
. The working fluid in the advance hydraulic chamber
54
is not supplied to the hydraulic chamber
46
. At this time, because the hydraulic pressure of the hydraulic chamber
46
is equal to the atmospheric pressure, the hydraulic pressure does not act as the force to push the stopper piston
32
toward the fitting member
49
.
As shown in
FIG. 7C
, when the vane rotor
15
rotates toward the retard side with respect to the shoe housing
12
in the state that the stopper piston
32
is pulled out from the fitting bore
41
and the enlarged bore
43
, the circumferential position of the stopper piston
32
and that of the fitting bore
41
are deviated each other. As a result, it becomes impossible for the stopper piston
32
to be fitted in the fitting bore
41
.
In operation of the third embodiment, when an ignition is turned off to stop the engine, a valve position
213
a
is selected because the ECU
300
turns off a current supplied to the solenoid
215
. Then, working fluid is supplied to the advance hydraulic chambers and the hydraulic chambers
45
and
46
. The retard hydraulic chambers and the hydraulic chamber
42
are opened to the drain. Thereby, the vane rotor
15
is rotated to the advance side with respect to the shoe housing
12
.
At this time, when the stopper piston
32
is separated from the fitting member
40
far from the position as shown in
FIG. 3C
, that is, when the stopper piston
32
is in unconstraint from the fitting bore
41
and the enlarged bore
43
, the communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down by the large diameter sliding portion
34
. Therefore, the hydraulic pressure of the hydraulic chamber
46
does not act to push the stopper piston
32
toward the fitting member
40
. However, because the hydraulic pressure in the hydraulic chamber
42
decrease, the urging force of the spring
37
pushes the stopper piston
32
to move toward the fitting member
40
.
When an engine stop is indicated in the state that the vane rotor
15
is positioned with deviation to the retard side with respect to the shoe housing
12
from the intermediate position (constraint position) where the stopper piston
32
is fitted in the fitting bore
41
, the working fluid is supplied to the advance hydraulic chambers to thereby rotate the vane rotor
15
to the advance side. The stopper piston
32
is moved toward the fitting member
40
by means of the urging force of the spring
37
, and the unconstraint state changes to the constraint state. At this time, the large diameter sliding portion
34
releases the closed through hole
30
b,
and the through hole
30
b
begins to open.
Then, the hydraulic chamber
46
becomes communicative to the advance hydraulic chamber
54
through the through hole
30
b,
and the working fluid is supplied from the advance hydraulic chamber
54
to the hydraulic chamber
46
. Therefore, the hydraulic pressure of the hydraulic chamber
46
acts as a pushing force that pushes the stopper piston
32
toward the fitting member
40
.
As shown in
FIG. 9
, when the vane
15
b
is stopped by the shoe
12
b
and the vane rotor
15
reaches the most advanced position with respect to the shoe housing
12
, the stopper piston
32
is positioned in the enlarged bore
43
as shown in FIG.
7
B.
When the vane rotor
15
reaches the intermediate position (constraint position) shown in
FIG. 7A
with respect to the shoe housing
12
, the stopper piston
32
is stopped on the retard side end surface of the enlarged bore
43
. The stopper piston
32
is fitted in the fitting bore
41
by the urging force of the spring
37
and the force received from the hydraulic chamber
46
. When the stopper piston
32
is fitted in the fitting bore
41
, the through hole
30
a
is closed by the large diameter sliding portion
34
. Therefore, because the working fluid in the hydraulic chamber
45
does not act as a force to pull out the stopper piston
32
from the fitting bore
41
, the constraint state shown in
FIG. 7A
is held. If the stopper piston
32
fails to fit in the fitting bore
41
, then the vane rotor
15
rotates toward the advance side with respect to the intermediate position and fits in the enlarged bore
43
.
When an engine stop is instructed in the state that the vane rotor
15
is positioned on the advance side with respect to the shoe housing
12
from the intermediate position where the stopper piston
32
is fitted in the fitting bore
41
, the vane rotor
15
rotates toward the advance side. The stopper piston
32
is thereby fitted in the enlarged bore
43
.
In the case that the stopper piston
32
is fitted in the fitting bore
41
before the engine is started, the phase difference of the vane rotor
15
with respect to the shoe housing
12
, that is, the phase difference of the camshaft
2
with respect to the crankshaft, is held in the most preferable phase for starting the engine. As a result, the engine can be started surely in a short time.
It is assumed that the engine is started in the state that the stopper piston
32
is not fitted in the fitting bore
41
before the engine is started and the camshaft
2
is positioned on the advance side to the crankshaft with respect to the intermediate position. At this time, the stopper piston
32
is fitted in the enlarged bore
43
. Because the advance torque exerted on the vane rotor
15
and the camshaft
2
by the spring
24
is approximately equal to the averaged load torque, the maximum value of the load torque exerted in the positive side retard direction is larger than the urging force of the spring
24
.
Because the working fluid is not supplied to the retard hydraulic chambers and the advance hydraulic chambers during cranking when the engine is to be started, the vane rotor
15
swings toward the retard side with respect to the shoe housing
12
against the urging force of the spring
24
that is exerted in the advance direction concomitantly with the variation of the load torque. The vane rotor
15
is stopped on the surface of the retard side of the enlarged bore
43
at the intermediate position.
When the stopper piston
32
reaches the intermediate position, the stopper piston
32
is fitted in the fitting bore
41
by means of the urging force of the spring
37
and the force received from the hydraulic chamber
46
because the working fluid is not introduced in the hydraulic chambers
42
and
45
.
The stopper piston
32
is fitted in the enlarged bore
43
, even though the stopper piston
32
is not fitted in the fitting bore
41
before the engine is started. The stopper piston
32
is fitted in the fitting bore
41
promptly when the engine is started, the camshaft
2
is held at the intermediate position with respect to the crankshaft, and thereby the engine is started surely in a short time.
Because the valve position
213
a
of the switching valve
212
is selected during cranking when the engine is to be started, the working fluid is supplied to the advance hydraulic chambers and the hydraulic chambers
45
and
46
. The retard hydraulic chambers and the hydraulic chamber
42
are opened to the drain. Furthermore, in the state that the stopper piston
32
is fitted in the fitting bore
41
as shown in
FIG. 7A
, the through hole
30
a
is closed by the large diameter sliding portion
34
. Thus, the working fluid in the hydraulic chamber
45
does not exert a force to pull out the stopper piston
32
from the fitting bore
41
. Therefore, the stopper piston
32
is not pulled out from the fitting bore
41
.
After the working fluid is charged in the retard hydraulic chamber and the hydraulic pressure increases up to a predetermined pressure after the engine is started, the stopper piston
32
is pulled out from the fitting bore
41
, the relative rotation of the vane rotor
15
with respect to the shoe housing
12
, that is, the phase control becomes possible. Because the through hole
30
b
is closed by the large diameter sliding portion
34
when the stopper piston
32
moves in the unconstraint direction shown in
FIG. 7C
from the fitting bore
41
, communication between the hydraulic chamber
46
and the advance hydraulic chamber
54
is shut down, and the hydraulic chamber
46
is almost sealed.
When the hydraulic pressure of the working fluid increases sufficiently after the engine is started, the any one of the valve positions
213
a,
213
b
and
213
c
of the valve member
213
is selected correspondingly to the instruction supplied from the ECU
300
. Thereby, supply of the working fluid to the hydraulic chambers and discharge of the working fluid from the hydraulic chambers are controlled. The relative rotation of the vane rotor with respect to the shoe housing
12
is controlled.
The stopper piston
32
is positioned at the place farther from the position shown in
FIG. 7C
in the pulling out direction. Therefore, the hydraulic chamber
46
is almost sealed as described above, when the stopper piston
32
is to be moved toward the fitting member
40
due to reduction of the hydraulic pressure of the hydraulic chambers
42
and
45
. The hydraulic chamber
46
functions as a damper chamber to thereby reduce the moving speed.
Therefore, when the stopper piston
32
passes through the intermediate position during advance angle control, the stopper piston
32
passes on the fitting member
40
before the stopper piston
32
is fitted in the fitting member
40
by means of the damper action of the hydraulic chamber
46
in addition to the advance hydraulic pressure exerted on the annular surface
34
a.
As a result, the stopper piston
32
is prevented from being fitted with the fitting member
40
.
When the stopper piston
32
passes through the intermediate position during retard angle control, the stopper piston
32
passes on the fitting member
40
before the stopper piston
32
is fitted with the fitting member
40
by means of the damper action of the hydraulic chamber
46
in addition to the retard hydraulic pressure exerted on the tope end surface
33
b.
The stopper piston
32
is prevented from being fitted with the fitting member
40
. The stopper piston
32
has the top end surface
33
b
on which the retard hydraulic pressure is exerted in the direction to pull out the stopper piston
32
from the fitting member
40
, and has the annular surface
34
a
on which the advance hydraulic pressure is exerted in the direction to pull out the stopper piston
32
from the fitting member
40
. As a result, the stopper piston
32
is held in the unconstraint state associated with the fitting member
40
. Furthermore, because the hydraulic chamber
46
functions as a damper chamber in the unconstraint state, the stopper piston
32
is held in the unconstraint state associated with the fitting member
40
.
In the third embodiment, the through hole
30
a
that communicates between the hydraulic chamber
45
and the advance hydraulic chamber
54
and the through hole
30
b
that communicates between the hydraulic chamber
46
and the advance hydraulic chamber
54
are opened/closed by displacing the stopper piston
32
. Thus, the through holes
30
a
and
30
b
are opened/closed surely by displacing the stopper piston
32
. Because other open/close valves and switching valves are not needed for opening/closing the through holes
30
a
and
30
b,
the number of needed parts is reduced, assembling work becomes simple, and the manufacturing cost is reduced.
Furthermore, the pressure receiving area of the top end surface
33
b
is larger than that of the annular surface
34
a
and the annular surface
34
b.
Therefore, even though the retard hydraulic pressure decreases due to pulsation, the stopper piston
32
and the fitting member
40
are held in the unconstraint state by means of the force received from the retard hydraulic pressure.
Furthermore, the force received from the hydraulic chamber
45
in the direction to pull out the stopper piston
32
from the fitting bore
41
is larger than the force received from the hydraulic chamber
46
in the direction to push the stopper piston
32
toward the fitting member
40
. Therefore, the unconstraint state associated with the stopper piston
32
and the fitting member
40
can be held during normal operation of the engine.
(Fourth Embodiment)
In a fourth embodiment shown in
FIGS. 12A and 12B
, the stopper piston
32
has the top end surface
33
a
that serves as the first pressure receiving portion formed on the top end, the annular surface
34
a
that serves as the second pressure receiving portion formed on the fitting bore side of the large diameter sliding portion
34
and the annular surface
34
b
that serves as the third pressure receiving portion formed on the side opposite to the fitting bore side of the large diameter sliding portion
34
. The pressure receiving area of the top end surface
32
a
is larger than the pressure receiving surface of the annular surface
34
a
and the annular surface
34
b.
Furthermore, the pressure receiving area of the annular surface
34
a
is larger than the pressure receiving surface of the annular surface
34
b.
It is possible that the through hole
30
a
that serves as the second pressure receiving passage formed on the guide ring
30
supplies the working fluid of the advance hydraulic pressure to the hydraulic chamber
45
. The through hole
30
a
is restricted at some portion of the passage. When the stopper piston
32
is to be moved toward the fitting member
40
side, the restricted passage of the through hole
30
a
functions to reduce the speed of motion of the stopper piston
32
toward the fitting member
40
. Therefore, the fitting of the stopper piston
32
in the fitting member
40
due to reduction of the working fluid hydraulic pressure during normal operation of the engine is prevented, and the phase is controlled smoothly.
The through hole
30
b
that serves as the third pressure receiving passage formed on the guide ring
30
supplies the working fluid of the advance hydraulic pressure to the hydraulic chamber
46
. As shown in
FIG. 12B
, the through hole
30
b
is closed by the large diameter portion
34
when the stopper piston
32
is positioned farthest from the fitting member
40
, but is opened when the stopper piston
32
moves only slightly toward the fitting member
40
side from the position shown in FIG.
12
B. Therefore, the hydraulic chamber
46
functions to push the stopper piston
32
toward the fitting member
40
when the working fluid of the advance hydraulic pressure is supplied, and does not act as a damper chamber.
The taper angle θ of the top end
34
of the stopper piston
32
is smaller than 15 degrees as in the second embodiment (FIG.
6
A). Further, the diameter D
2
of the fitting bore
41
in the direction perpendicular to the rotation direction is larger than the diameter D
1
of the fitting bore
41
in the rotation direction as in the second embodiment (FIG.
6
B).
Even if the fitting bore
41
or the stopper piston
32
has some manufacturing allowance in the direction perpendicular to the rotation direction, the stopper piston
32
can be fitted in the fitting bore
41
. Because the limit of the manufacturing allowance is eased, the manufacturing cost is reduced.
In the third and fifth embodiments, the retard hydraulic pressure and advance hydraulic pressure are exerted on the stopper piston in the direction to be pulled out from the fitting bore and enlarged bore. Either of the retard hydraulic pressure and the advance hydraulic pressure is exerted on the stopper piston in the direction to be pulled out from the fitting bore and the enlarged bore during phase control in normal operation of the engine. The stopper piston is prevented from being fitted in the fitting bore during normal operation of the engine.
Furthermore, the advance hydraulic pressure is exerted on the stopper piston in the direction to be pushed toward the fitting member. Therefore, when an engine stop is instructed, the stopper piston is surely fitted in the fitting bore at the intermediate position because the retard hydraulic chamber is opened to the drain and the working fluid is supplied to the advance hydraulic chamber.
In the third to fifth, the first pressure receiving portion for receiving the retard hydraulic pressure in the direction to pull out the stopper piston from the fitting bore and the second pressure receiving portion for receiving the advance hydraulic pressure in the direction to pull out the stopper piston from the fitting bore are formed separately on the stopper piston. Alternatively, one pressure receiving portion for receiving the hydraulic pressure in the direction to pull out the stopper piston from the fitting bore may be formed, and the retard hydraulic pressure and the advance hydraulic pressure may be switched by use of, for example, a differential pressure regulating valve to thereby exert the retard hydraulic pressure or the advance hydraulic pressure that has been switched to the pressure receiving portion.
The present invention should not be limited to the above disclosed embodiments, but may be implemented in many other ways.
For instance, the vale timing adjusting apparatus drives only the exhaust valve, or both the suction valve and exhaust valve. Further, the stopper piston may be moved in the radial direction to be fitted in the fitting bore. The stopper piston may be accommodated in the housing member side and the fitting bore, and the enlarged bore may be formed on the vane rotor side. A timing pulley or timing gear may be employed in place of the chain sprocket. The driving force of the crankshaft that serves as the driving shaft may be received by the vane member to rotate the camshaft that serves as the driven shaft and the housing member.
Claims
- 1. A valve timing adjusting apparatus for transmitting a driving force from a driving shaft of an internal combustion engine to a driven shaft for opening/closing at least one of a suction valve and an exhaust valve, the apparatus comprising:a driving side rotor that rotates together with the driving shaft; a driven side rotor that rotates together with the driven shaft and that is relatively rotationally driven with respect to the driving side rotor by means of working fluid pressure; an accommodation chamber formed in one of the driving side rotor and the driven side rotor; a vane formed with the other of the driving side rotor and the driven side rotor and accommodated in the accommodation chamber; constraint means provided on the driving side rotor and the driven side rotor, the constraint means having a contact portion and a contact receiving portion for constraining a relative rotation of the driven side rotor with respect to the driving side rotor by being in contact each other when the driven side rotor is positioned at an intermediate position with respect to the driving side rotor between both ends in a circumferential direction in a predetermined angular range, and the constraint means having contact urging means for urging the contact portion in a direction to be brought into contact with the contact receiving portion, wherein the contact portion receives a force in a direction to release a constraint with the contact receiving portion against an urging force of the contact urging means by means of a first working fluid pressure that drives the driven side rotor toward one of an advance side and a retard side with respect to the driving side rotor, and receives a force in a direction to be brought into contact with the contact receiving portion by means of a second working fluid pressure that drives the driven side rotor in a direction of the other of the advance side and the retard side with respect to the driving side rotor.
- 2. The valve timing adjusting apparatus as in claim 1, wherein the first working fluid pressure is applied to rotate the driven side rotor to the retard side, and the second working fluid pressure is applied to rotate the driven side rotor to the advance side.
- 3. The valve timing adjusting apparatus as in claim 1, wherein the contact portion has a first pressure receiving portion that receives the first working fluid pressure, and has a second pressure receiving portion that receives the second working fluid pressure in a direction opposite to a receiving direction of the first working fluid pressure applied to the first pressure receiving portion.
- 4. The valve timing adjusting apparatus as in claim 1, wherein the contact portion has a first pressure receiving portion and a third pressure receiving portion that receive a first working fluid pressure in the same direction, and has a second pressure receiving portion that receives the second working fluid pressure in a direction opposite to a receiving direction of the first working fluid pressure applied to the first pressure receiving portion.
- 5. The valve timing adjusting apparatus as in claim 1, further comprising:a working fluid passage for supplying the second working fluid to the contact portion, wherein the working fluid passage is closed while the contact portion is being unconstrained with the contact receiving portion, and is opened when the unconstraint state associated with the contact portion and the contact receiving portion changes to the constraint state.
- 6. The valve timing adjusting apparatus as in claim 5, wherein opening/closing of the working fluid passage is operated by means of displacement of the contact portion.
- 7. The valve timing adjusting apparatus as in claim 1, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion, and the contact portion and the fitting bore are formed to have a circular cross section with taper.
- 8. The valve timing adjusting apparatus as in claim 7, wherein the taper angle of the contact portion is smaller than 15 degrees.
- 9. The valve timing adjusting apparatus as in claim 1, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion and that is formed to be shallower than the fitting bore around the fitting bore so that the driven side rotor is prevented from rotating toward the retard side beyond an intermediate position between a most retarded angle and a most advanced angle, and has an enlarged bore that allows the driven side rotor to rotate toward the advance side beyond the intermediate position.
- 10. The valve timing adjusting apparatus as in claim 1, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion and that is formed in the form of a slotted hole in a direction perpendicular to the rotation direction of the fitting bore.
- 11. The valve timing adjusting apparatus as in claim 1, wherein a damper chamber for reducing the displacement speed of the contact portion in the direction to be brought into contact with the contact receiving portion in the unconstraint state is formed on the outer periphery of the contact portion.
- 12. The valve timing adjusting apparatus as in claim 11, wherein a damper action of the damper chamber is released when the unconstraint state associated with the contact portion and the contact receiving portion changes to the constraint state.
- 13. The valve timing adjusting apparatus as in claim 12, wherein the damper action of the damper chamber is released by displacing the contact portion.
- 14. The valve timing adjusting apparatus as in claim 1, further comprising:advance urging means for urging the driven side rotor toward the advance side.
- 15. The valve timing adjusting apparatus as in claim 1, wherein a side opposite to the contact receiving side of a space for accommodating the contact portion is open to atmosphere in the relative rotation angle range of the driven side rotor with respect to the driving side rotor.
- 16. A valve timing adjusting apparatus for transmitting a driving force from a driving shaft of an internal combustion engine to a driven shaft for opening/closing at least one of a suction valve and an exhaust valve, the apparatus comprising:a driving side rotor that rotates together with the driving shaft; a driven side rotor that rotates together with the driven shaft and that is relatively rotationally driven with respect to the driving side rotor by means of working fluid pressure; an accommodation chamber formed in one of the driving side rotor and the driven side rotor; a vane formed with the other of the driving side rotor and the driven side rotor and accommodated in the accommodation chamber; constraint means provided on the driving side rotor and the driven side rotor, the constraint means having a contact portion and a contact receiving portion for constraining a relative rotation of the driven side rotor with respect to the driving side rotor by being in contact each other when the driven side rotor is positioned at an intermediate position with respect to the driving side rotor between both ends in a circumferential direction in a predetermined angular range, and the constraint means having contact urging means for urging the contact portion in a direction to be brought into contact with the contact receiving portion, wherein the contact portion receives a force in a direction to release a constraint with the contact receiving portion against an urging force of the contact urging means by means of a first working fluid pressure that drives the driven side rotor toward one of an advance side and a retard side with respect to the driving side rotor and a second working fluid pressure that drives the driven side rotor in a direction of the other of the advance side and the retard side with respect to the driving side rotor, and receives a force in a direction to be brought into contact with the contact receiving portion by means of the second working fluid pressure.
- 17. The valve timing adjusting apparatus as in claim 16, wherein the first working fluid pressure is applied to rotate the driven side rotor to the retard side, and the second working fluid pressure is applied to rotate the driven side rotor to the advance side.
- 18. The valve timing adjusting apparatus as in claim 16, wherein the contact portion has a first pressure receiving portion that receives the first working fluid pressure, a second pressure receiving portion that receives the second working fluid pressure in a same direction as a receiving direction of the first working fluid pressure applied to the first pressure receiving portion, and a third pressure receiving portion that receives the second working fluid in a direction opposite to the receiving direction of the second pressure receiving portion.
- 19. The valve timing adjusting apparatus as in claim 18, wherein a pressure receiving area of the first pressure receiving portion is larger than a pressure receiving area of the second pressure receiving portion and the third pressure receiving portion.
- 20. The valve timing adjusting apparatus as in claim 18, wherein the pressure receiving area of the second pressure receiving portion is larger than the pressure receiving area of the third pressure receiving portion.
- 21. The valve timing adjusting apparatus as in claim 18, wherein a pressure receiving passage for supplying the second working fluid to the third pressure receiving portion is closed in an unconstraint state associated with the contact portion and the contact receiving portion, and is opened when the unconstraint state associated with the contact portion and the contact receiving portion changes to the constraint state.
- 22. The valve timing adjusting apparatus as in claim 21, wherein the pressure receiving passage is opened/closed by displacing the contact portion.
- 23. The valve timing adjusting apparatus as in claim 18, wherein a pressure receiving passage for supplying the second working fluid to the second pressure receiving portion is closed immediately before the contact portion is brought into contact with the contact receiving portion.
- 24. The valve timing adjusting apparatus as in claim 23, wherein opening/closing of the working fluid passage is operated by means of displacement of the contact portion.
- 25. The valve timing adjusting apparatus as in claim 18, wherein the pressure receiving passage for supplying the second working fluid to the second pressure receiving portion is provided with a restrictor.
- 26. The valve timing adjusting apparatus as in claim 16, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion, and the contact portion and the fitting bore are formed to have a circular cross section with taper.
- 27. The valve timing adjusting apparatus as in claim 26, wherein the taper angle of the contact portion is smaller than 15 degrees.
- 28. The valve timing adjusting apparatus as in claim 16, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion and that is formed in the form of a slotted hole in a direction perpendicular to the rotation direction of the fitting bore.
- 29. The valve timing adjusting apparatus as in claim 16, wherein the contact receiving portion has a fitting bore that can be fitted with the contact portion, and has an enlarged bore formed around the fitting bore to be shallower in depth than the fitting bore that allows the driven side rotor to rotate toward the advance side beyond the intermediate position between the most retarded angle and the most advanced angle.
- 30. The valve timing adjusting apparatus as in claim 16, wherein a damper chamber for reducing the displacement speed of the contact portion in the direction to be brought into contact with the contact receiving portion in the unconstraint state is formed on an outer periphery of the contact portion.
- 31. The valve timing adjusting apparatus as in claim 30, wherein a damper action of the damper chamber is released when the unconstraint state associated with the contact portion and the contact receiving portion changes to the constraint state.
- 32. The valve timing adjusting apparatus as in claim 31, wherein the damper action of the damper chamber is released by displacing the contact portion.
- 33. The valve timing adjusting apparatus as in claim 16, further comprising:advance urging means for urging the driven side rotor toward the advance side.
- 34. The valve timing adjusting apparatus as in claim 16, wherein a side opposite to the contact receiving side of a space for accommodating the contact portion is open to atmosphere in the relative rotation angle range of the driven side rotor with respect to the driving side rotor.
Priority Claims (2)
Number |
Date |
Country |
Kind |
11-223974 |
Aug 1999 |
JP |
|
11-223987 |
Aug 1999 |
JP |
|
US Referenced Citations (3)