U.S. patent application number 10/862322 was filed with the patent office on 2005-01-27 for variable valve timing control device.
This patent application is currently assigned to AISIN SEIKI KABUSHIKI KAISHA. Invention is credited to Kawai, Yoshiyuki, Kobayashi, Masaki.
Application Number | 20050016482 10/862322 |
Document ID | / |
Family ID | 33296903 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050016482 |
Kind Code |
A1 |
Kobayashi, Masaki ; et
al. |
January 27, 2005 |
Variable valve timing control device
Abstract
A variable valve timing control device includes a rotating
member, a rotation transmitting member and a retracting portion
accommodating a lock member biased by a spring. The variable valve
timing control device further includes a spring receiving bore
connected to the retracting portion for accommodating the spring
and including a guide portion for guiding the spring in the axial
direction, a receiving portion into which a head portion of the
lock member is inserted at a predetermined relative rotation phase.
A length of the guide portion in the axial direction is larger than
each distance formed between windings of the spring adjacent to
each other in the axial direction.
Inventors: |
Kobayashi, Masaki;
(Toyota-shi, JP) ; Kawai, Yoshiyuki; (Toyota-shi,
JP) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
AISIN SEIKI KABUSHIKI
KAISHA
1, Asahi-machi 2-chome
Kariya-shi
JP
448-8650
|
Family ID: |
33296903 |
Appl. No.: |
10/862322 |
Filed: |
June 8, 2004 |
Current U.S.
Class: |
123/90.17 ;
123/90.15 |
Current CPC
Class: |
F01L 2001/34469
20130101; F01L 2001/34473 20130101; F01L 1/3442 20130101; F01L
2001/34483 20130101; F01L 1/022 20130101 |
Class at
Publication: |
123/090.17 ;
123/090.15 |
International
Class: |
F01L 001/34; A44B
009/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2003 |
JP |
2003-169287 |
Claims
We claim:
1. A variable valve timing control device comprising: a rotating
member integrally connected to a camshaft for opening and closing a
valve and rotatably assembled to a cylinder head of an internal
combustion engine; a rotation transmitting member assembled to the
rotating member so as to be rotatable relative thereto within a
predetermined range and to which a rotation force from a crankshaft
is transmitted; a vane provided on either one of the rotating
member and the rotation transmitting member; a fluid pressure
chamber formed between the rotating member and the rotation
transmitting member and divided into an advanced angle chamber and
a retarded angle chamber by the vane; a first fluid passage and a
second fluid passage through which an operation fluid is
selectively supplied to or discharged from the advanced angle
chamber and the retarded angle chamber respectively; a retracting
portion formed on either one of the rotation transmitting member
and the rotating member and accommodating a lock member biased
towards either one of the rotation transmitting member and the
rotating member by a spring; the spring including a winding portion
formed by a plurality of windings and both end portions in an axial
direction of the spring; a spring receiving bore connected to the
retracting portion for accommodating the spring and including a
guide portion for guiding the spring in the axial direction of the
spring; a receiving portion formed on either one of the rotating
member and the rotation transmitting member and into which a head
portion of the lock member is inserted when a relative rotation
phase between the rotating member and the rotation transmitting
member is positioned at a predetermined phase; and a third fluid
passage through which the operation fluid is supplied to or
discharged from the receiving portion; wherein a length of the
guide portion in the axial direction is larger than each distance
formed between the windings of the spring adjacent to each other in
the axial direction.
2. A variable valve timing control device according to claim 1,
wherein the spring receiving bore includes a concave corner at a
connecting portion between an inner circumferential face of the
guide portion and both end portions of the spring receiving bore in
the radial direction thereof to which the both end portions of the
spring contact respectively.
3. A variable valve timing control device according to claim 1,
wherein the guide portion is formed between an outer circumference
of the winding portion and an inner circumference of the spring
receiving bore.
4. A variable valve timing control device according to claim 2,
wherein the guide portion is formed between an outer circumference
of the winding portion and an inner circumference of the spring
receiving bore.
5. A variable valve timing control device according to claim 1,
wherein the both end portions of the spring in the axial direction
are formed in parallel to a face defined perpendicular to the axial
direction of the spring.
6. A variable valve timing control device comprising: a rotating
member integrally connected to a camshaft for opening and closing a
valve and rotatably assembled to a cylinder head of an internal
combustion engine; a rotation transmitting member assembled to the
rotating member so as to be rotatable relative thereto within a
predetermined range and to which a rotation force from a crankshaft
is transmitted; a retracting portion formed on either one of the
rotation transmitting member and the rotating member and
accommodating a lock member biased towards either one of the
rotation transmitting member and the rotating member by a spring;
the spring including a winding portion formed by a plurality of
windings and both end portions in an axial direction of the spring;
a spring receiving bore connected to the retracting portion for
accommodating the spring and including a guide portion for guiding
the spring in the axial direction of the spring; a receiving
portion formed on either one of the rotating member and the
rotation transmitting member and into which a head portion of the
lock member is inserted when a relative rotation phase between the
rotating member and the rotation transmitting member is positioned
at a predetermined phase; wherein a length of the guide portion in
the axial direction is larger than each distance formed between the
windings of the spring adjacent to each other in the axial
direction.
7. A variable valve timing control device according to claim 6,
wherein the spring receiving bore includes a concave corner at a
connecting portion between an inner circumferential face of the
guide portion and both end portions of the spring receiving bore in
the radial direction thereof to which the both end portions of the
spring contact respectively.
8. A variable valve timing control device according to claim 6,
wherein the guide portion is formed between an outer circumference
of the winding portion and an inner circumference of the spring
receiving bore.
9. A variable valve timing control device according to claim 7,
wherein the guide portion is formed between an outer circumference
of the winding portion and an inner circumference of the spring
receiving bore.
10. A variable valve timing control device according to claim 6,
wherein the both end portions of the spring in the axial direction
are formed in parallel to a face defined perpendicular to the axial
direction of the spring.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Application 2003-169287, filed
on Jun. 13, 2003, the entire content of which is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] This invention generally relates to a variable valve timing
control device. More particularly, the present invention pertains
to a variable valve timing control device for controlling an
opening and closing timing of an intake valve and exhaust valve of
an internal combustion engine.
BACKGROUND
[0003] A known variable valve timing control device is disclosed in
Japanese Patent Laid-Open Publication No. 2003-13713. The disclosed
variable valve timing control device includes a rotating member
integrally connected to a camshaft for opening and closing a valve,
and a rotation transmitting member to which a rotation force from a
crankshaft is transmitted. The rotation transmitting member is
assembled to the rotating member so as to be rotatable relative
thereto within a predetermined range. The variable valve timing
control device also includes vanes each assembled to the rotating
member and dividing a fluid chamber defined within the rotation
transmitting member into an advanced angle chamber and a retarded
angle chamber. The variable valve timing control device further
includes a first fluid passage and a second fluid passage through
which an operation fluid is supplied to or discharged from the
advanced angle chamber and the retarded angle chamber,
respectively. The rotating member and the rotation transmitting
member are relatively rotated to each other by the operation fluid
to be supplied to or discharged from each fluid pressure chamber.
The rotation transmitting member includes a retracting groove
portion for receiving a lock member biased towards the rotating
member by a spring. The rotation transmitting member also includes
a spring receiving bore connected to the retracting groove portion
for receiving the spring, and formed with a guide portion for
guiding the spring in an axial direction of the spring. The
rotating member includes a receiving portion into which a head
portion of the lock member is inserted when a relative rotation
phase between the rotating member and the rotation transmitting
member is positioned at a predetermined phase. The relative
rotation of the rotation transmitting member to the rotating member
is restricted by engaging the lock member and the receiving portion
with each other.
[0004] According to the above-mentioned variable valve timing
control device, an appropriate clearance is provided between an
outer circumference of a winding portion of the spring and an inner
circumference of the spring receiving bore for forming a guide
portion that guides the spring so that the winding portion of the
spring is prohibited to be bent when the spring is compressed or
extended along with the operation of a lock plate (lock member). In
addition, concave corners R are formed at connecting portions
between an inner circumferential face of the guide portion and the
both end portions of the spring receiving bore in the radial
direction thereof to which the both end portions of the spring
contact respectively, i.e. end portions of the guide portion in the
axial direction, for assuring contact faces for both end portions
of the spring and also preventing stress occurring when the
rotation force is added in the rotating direction in case that the
relative rotation between the rotating member and the rotation
transmitting member is restricted.
[0005] According to the above-mentioned structure, when the spring
is assembled to the spring receiving bore or the head portion of
the lock member is inserted into the receiving portion and thus the
spring is extended, the winding portion of the spring may climb
over the end portion of the guide portion (concave corner R) and
impossible to be compressed. Therefore, the lock member may be not
received in the retracting groove portion, thereby causing the
malfunction of the variable valve timing control device.
[0006] Thus, a need exists for a variable valve timing control
device wherein a winding portion of a spring biasing a lock member
is prevented from climbing over a guide portion during a valve
timing control.
SUMMARY OF THE INVENTION
[0007] According to an aspect of the present invention, a variable
valve timing control device comprising, a rotating member
integrally connected to a camshaft for opening and closing a valve
and rotatably assembled to a cylinder head of an internal
combustion engine, a rotation transmitting member assembled to the
rotating member so as to be rotatable relative thereto within a
predetermined range and to which a rotation force from a crankshaft
is transmitted, a retracting portion formed on either one of the
rotation transmitting member and the rotating member and
accommodating a lock member biased towards either one of the
rotation transmitting member and the rotating member by a spring.
The spring including a winding portion formed by a plurality of
windings and both end portions in an axial direction of the spring,
a spring receiving bore connected to the retracting portion for
accommodating the spring and including a guide portion for guiding
the spring in the axial direction of the spring, a receiving
portion formed on either one of the rotating member and the
rotation transmitting member and into which a head portion of the
lock member is inserted when a relative rotation phase between the
rotating member and the rotation transmitting member is positioned
at a predetermined phase. A length of the guide portion in the
axial direction is larger than each distance formed between the
windings of the spring adjacent to each other in the axial
direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The foregoing and additional features and characteristics of
the present invention will become more apparent from the following
detailed description considered with reference to the accompanying
drawings, wherein:
[0009] FIG. 1 is a longitudinal sectional view of a variable valve
timing control device taken along the line A-A of FIG. 2 according
to an embodiment of the present invention;
[0010] FIG. 2 is a cross-sectional view of the variable valve
timing control device in a retarded angle phase, taken along the
line B-B of FIG. 1 according to the embodiment of the present
invention;
[0011] FIG. 3 is a cross-sectional view of the variable valve
timing control device in an intermediate angle phase, taken along
the line B-B of FIG. 1 according to the embodiment of the present
invention; and
[0012] FIG. 4 is a longitudinal sectional view of the variable
valve timing control device and also an enlarged view of D portion
of FIG. 2 according to the embodiment of the present invention.
DETAILED DESCRIPTION
[0013] An embodiment of the present invention is explained
referring to attached drawings.
[0014] A variable valve timing control device 1 shown in FIGS. 1 to
4 includes a rotating member 2 for opening/closing a valve, which
includes a camshaft 10 rotatably supported on a cylinder head 100
of an internal combustion engine and an inner rotor 20 integrally
fixed to a tip end portion of the camshaft 10. The variable valve
timing control device 1 also includes a rotation transmitting
member 3 having an outer rotor 30 being rotatable relative to the
inner rotor 20 within a predetermined range, a front plate 40, and
a rear plate 50. A timing sprocket 31 is integrally formed on an
outer periphery of the outer rotor 30. Further, the variable valve
timing control device 1 includes a torsion spring 60 disposed
between the inner rotor 20 and the front plate 40, four vanes 70
assembled to the inner rotor 20, and a lock plate 80 (see FIG. 2)
assembled to the outer rotor 30.
[0015] The timing sprocket 31 receives the rotation force in the
clockwise direction thereof, which is shown as a rotation direction
of camshaft in FIG. 2. The rotation force is transmitted from a
crankshaft (not shown) via a crank sprocket (not shown) and a
timing chain (not shown).
[0016] The camshaft 10 includes a known cam (not shown) for
opening/closing an intake valve (not shown). An advanced angle
fluid passage (first fluid passage) 11 and a retarded angle fluid
passage (second fluid passage) 12 extending in an axial direction
of the camshaft 10 are provided inside of the camshaft 10. The
advanced angle fluid passage 11 is connected to a first connecting
port 201 of a switching valve 200 via a passage 71 provided on the
camshaft 10 in the radial direction thereof, an annular groove 14,
and a connecting passage 16 provided on the cylinder head 100. In
addition, the retarded angle fluid passage 12 is connected to a
second connecting port 202 of the switching valve 200 via a passage
72 provided on the camshaft 10 in the radial direction thereof, an
annular groove 13, and a connecting passage 15 provided on the
cylinder head 100.
[0017] The switching valve 200 is a known type wherein a spool 204
is moved against a biasing force of a spring (not shown) by
energizing a solenoid 203. When the solenoid 203 is de-energized, a
supply port 206 connected to an oil pump 205 that is driven by the
internal combustion engine communicates with the second connecting
port 202. At the same time, the first connecting port 201
communicates with a discharge port 207. When the solenoid 203 is
energized, the supply port 206 communicates with the first
connecting port 201 and at the same time the second connecting port
202 communicates with the discharge port 207 as shown in FIG. 1.
Therefore, in case that the solenoid 203 of the switching valve 200
is de-energized, the operation fluid (fluid pressure) is supplied
to the retarded angle fluid passage 12. In case that the solenoid
203 is energized, the operation fluid is supplied to the advanced
angle fluid passage 11. Energization of the solenoid 203 of the
switching valve 200 is duty-controlled by which a ratio of
energization/de-energization per unit time is changed. For example,
when the switching valve 200 is duty-controlled at 50%, the first
and second ports 201 and 202, and the supply and discharge ports
206 and 207 are not connected to each other.
[0018] The inner rotor 20 is integrally fixed to the camshaft 10
via an installation bolt 91. As shown in FIG. 2, four vane grooves
21 and a receiving portion 22 are formed on the inner rotor 20. In
addition, three first fluid passages 23 extending in the radial
direction of the inner rotor 20, a fluid groove 23a, four second
fluid passages 24 extending in the radial direction of the inner
rotor 20, and a third fluid passage 25 for connecting a bottom
portion of the receiving portion 22 to the advanced angle fluid
passage 11.
[0019] As shown in FIG. 2, the vanes 70 are positioned in the vane
grooves 21 respectively, being movable in the radial direction of
the inner rotor 20. The four vanes 70 are movable within four fluid
pressure chambers R0 respectively, which are each defined between
the outer rotor 30 (to be explained later) and the inner rotor 20
and arranged, dividing each fluid pressure chamber R0 into an
advanced angle chamber R1 and a retarded angle chamber R2. Each
vane 70 is biased in the radially outward direction by a vane
spring 73 (see FIG. 1) disposed between the bottom portion of each
vane groove 21 and the bottom face of each vane 70.
[0020] In a state shown in FIG. 2, i.e. when a relative phase
between the camshaft 10 and the inner rotor 20, and the outer rotor
30 is positioned at a predetermined phase (i.e. most retarded angle
phase), a head portion 80a of the lock plate (lock member) 80
having a flat plate shape and movably assembled to the outer rotor
30 is inserted into the receiving portion 22 by a predetermined
amount so that the relative rotation between the outer rotor 30 and
the inner rotor 20 can be locked, i.e. restricted.
[0021] As shown in FIG. 2, the operation fluid (fluid pressure) is
supplied to or discharged from the four retarded angle chambers R2,
which are defined and divided by the vanes 70, via the retarded
angle fluid passage 12 and the second fluid passage 24. In
addition, the operation fluid is supplied to or discharged from
three advanced angle chambers R1 out of four via the advanced angle
fluid passage 11 and the first fluid passage 23. The operation
fluid is supplied to the lock plate 80 from the third fluid passage
25 formed on the bottom portion of the receiving portion 22. When
the lock plate 80 is moved, the operation fluid is supplied to or
discharged from the remaining (i.e. one out of four) advanced angle
chamber R1 via the fluid groove 23a connecting the third fluid
passage 25 and that advanced angle chamber R1. Accordingly, for one
advanced angle chamber R1 out of four, the first fluid passage 23
is not provided and the third fluid passage 25 is shared to be
used, which may achieve a simple structure of the fluid passage and
a reduced cost of manufacturing.
[0022] Both side portions of the outer rotor 30 in the axial
direction thereof are integrally fixed to the annular shaped front
plate. 40 and the rear plate 50 respectively via four connecting
bolts 92. The outer rotor 30 and the inner rotor 20 are rotatable
relative thereto within the predetermined range defined by the vane
70 and the lock plate 80 moved within the fluid pressure chamber
R0. The timing sprocket 31 is integrally formed on an outer
periphery of the outer rotor 30 and on an end side in the axial
direction thereof to which the rear plate 50 is connected. In
addition, five convex portions 33 are formed on the inner
circumference of the outer rotor 30 in the circumferential
direction thereof so as to project in the radially inward
direction. Each inner circumferential face of each convex portion
33 is slidably in contact with an outer circumferential face of the
inner rotor 20. That is, the outer rotor 30 is rotatably supported
on the inner rotor 20. A retracting groove portion 34 for
accommodating the lock plate 80, and a spring receiving bore 35
connected to the retracting groove portion 34 for accommodating a
coil spring 81 that biases the lock plate 80 in the radially inward
direction of the outer rotor 30 are formed between the two convex
portions 33 out of five. The four fluid pressure chambers R0
mentioned above are formed between five convex portions 33,
respectively.
[0023] As shown in FIG. 4, the coil spring 81 is arranged within
the spring receiving bore 35 pushing the lock plate 80 in the
radially inward direction of the outer rotor 30. The coil spring 81
includes a winding portion 81a and both end portions in the axial
direction of the spring 81. The winding portion 81a is formed by
spirally winding a wire rod, i.e. a plurality of windings, and
having a distance B defined between the windings adjacent to each
other in the axial direction as shown in FIG. 4. Both end portions
of the winding portion 81a in the axial direction are formed in
parallel to a face defined perpendicular to the axial direction of
the spring 81. An appropriate clearance is provided between an
outer circumference of the winding portion 81a and an inner
circumference of the spring receiving bore 35 for forming a guide
portion 35a that guides the coil spring 81 so that the winding
portion 81a of the coil spring 81 is prohibited to be bent when the
coil spring 81 is compressed or extended along with the operation
of the lock plate 80. In addition, a concave corner R is formed at
a connecting portion between an inner circumferential face of the
guide portion 35a and the both end portions of the spring receiving
bore 35 in the radial direction thereof to which the both end
portions of the coil spring 81 contact respectively, for assuring
contact faces for both end portions of the coil spring 81 and also
preventing stress occurring when the rotation force is added in the
rotating direction in case that the relative rotation between the
rotating member 2 and the rotation transmitting member 3 is
restricted. Under the above-mentioned structure, a length A of the
guide portion 35a in the axial direction of the coil spring 81 is
defined larger than the distance B of the coil spring 81 under the
condition that the lock plate 80 is engaged with the receiving
portion 22. Therefore, when the coil spring 81 is assembled to the
spring receiving bore 35 or the head portion 80a of the lock plate
80 is inserted into the receiving portion 22 and thus the coil
spring 81 is extended, the winding portion 81a is prevented from
climbing over the end portion (concave corner R) of the guide
portion 35a and also prevented from being disabled to be
compressed.
[0024] The torsion spring 60 is provided by engaging with the front
plate 40 at one end and the inner rotor 20 at the other end. The
torsion spring 60 biases the inner rotor 20 towards the advanced
angle side (clockwise direction in FIG. 2) relative to the outer
rotor 30, the front plate 40 and the rear plate 50. Thus, the
operation response of the inner rotor 20 to the advanced angle side
may be improved.
[0025] The relative rotation between the inner rotor 20 and the
outer rotor 30 to the advanced angle side is equal to the movement
of the vanes 70 in the advanced angle direction (clockwise
direction) as shown in FIG. 3 from the most retarded angle state as
shown in FIG. 2. The most advanced angle phase is restricted at a
position where the vane 70 is in contact with one side face of the
convex portion 33 in the circumferential direction thereof. The
most retarded angle phase is restricted at a position where the
head portion 80a of the lock plate 80 is positioned in the
receiving portion 22. According to the present embodiment, one of
the vanes 70 is in contact with the other side face of the convex
portion 33 in the circumferential direction thereof at the most
retarded angle phase.
[0026] According to the above-mentioned embodiment, when the
internal combustion engine is stopped, the oil pump 205 is stopped
and also the switching valve 200 is not energized. Thus, the
operation fluid is not supplied to the fluid pressure chambers R0.
As shown in FIG. 2, the inner rotor 20 and the outer rotor 30 are
positioned at the most retarded angle phase due to a cam friction
applied to the retarded angle direction. The head portion 80a of
the lock plate 80 is positioned within the receiving portion 22 of
the inner rotor 20 and thus the relative rotation between the inner
rotor 20 and the outer rotor 30 is restricted at the most retarded
angle phase. Even when the internal combustion engine is started
and the oil pump 205 is driven, the operation fluid supplied from
the oil pump 205 is only virtually provided to the retarded angle
chamber R2 via the connecting passage 15, the retarded angle fluid
passage 12, and the passage 24 while the duty ratio is small for
energizing the switching valve 200 (i.e. the ratio of energizing
time relative to the de-energizing time per unit time is small).
Therefore, the variable valve timing control device 1 is maintained
in a locked state.
[0027] When the retarded angle phase is required for the valve
timing depending on the operation condition of the internal
combustion engine, the duty ratio for energizing the switching
valve 200 is brought to be large and then the position of the spool
204 is switched. The operation fluid supplied from the oil pump 205
is provided to the advanced angle chamber R1 by passing through the
connecting passage 16, the advanced angle fluid passage 11, and the
first fluid passage 23, or by passing through the fluid groove 23a
after supplied to the receiving portion 22 from the third fluid
passage 25.
[0028] Meanwhile, the operation fluid stored in the retarded angle
chamber R2 is sent to the passage 24, the retarded angle fluid
passage 12, and the connecting passage 15 to be discharged from the
discharge port 207 of the switching valve 200. Therefore, the lock
plate 80 is moved against the biasing force of the spring 81,
thereby retracting the head portion 80a from the receiving portion
22. Then, the locked state between the inner rotor 20 and the outer
rotor 30 is released. At the same lime, the inner rotor 20
integrally rotating with the camshaft 10 and each vane 70 rotate
relative to the outer rotor 30, the front plate 40, and the rear
plate 50 in the advanced angle direction (clockwise direction in
FIG. 2). Due to the aforementioned relative rotation, the variable
valve timing control device 1 is shifted from the state in FIG. 2
to the state in FIG. 3. Then, the timing of the cam is brought in
the advanced angle state. The relative rotation phase may be
defined arbitrarily by controlling the duty ratio of the switching
valve 200. For example, the relative rotation between the inner
rotor 20 and the outer rotor 30 may be stopped at the intermediate
phase.
[0029] According to the aforementioned embodiment, the length A of
the guide portion 35a in the axial direction is defined larger than
each distance B formed between the windings of the coil spring 81
adjacent to each other in the axial direction. Therefore, when the
coil spring 81 is assembled to the spring receiving bore 35 or the
coil spring 81 is extended since the head portion 80a of the lock
plate 80 is positioned within the receiving portion 22, the lock
plate 80 is prevented from being disabled to be received in the
retracting groove portion 34 due to the windings climbing over the
end portion of the guide portion 35a (i.e. concave corner R) and
the winding portion 81a not being compressed.
[0030] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the spirit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *