U.S. patent application number 12/367694 was filed with the patent office on 2009-08-13 for valve timing adjusting apparatus.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Akio Imai, Yasushi Morii.
Application Number | 20090199801 12/367694 |
Document ID | / |
Family ID | 40847480 |
Filed Date | 2009-08-13 |
United States Patent
Application |
20090199801 |
Kind Code |
A1 |
Imai; Akio ; et al. |
August 13, 2009 |
VALVE TIMING ADJUSTING APPARATUS
Abstract
A valve timing adjusting apparatus includes a driving-side
rotor, a driven-side rotor, a sun gear, and a planet gear. The
driving-side rotor is rotatable synchronously with the crankshaft.
The driven-side rotor is received in the driving-side rotor and
rotatable synchronously with a camshaft. The sun gear is rotatable
integrally with the driving-side rotor. The planet gear moves
epicyclically relative to the sun gear. The driving-side rotor
includes a peripheral wall member and a bottom wall member. One of
the sun gear and the bottom wall member is fitted with an inner
peripheral side of one axial end portion of the peripheral wall
member. The other one is fitted with an outer peripheral side of
the other axial end portion of the peripheral wall member.
Inventors: |
Imai; Akio; (Kariya-city,
JP) ; Morii; Yasushi; (Nagoya-city, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
40847480 |
Appl. No.: |
12/367694 |
Filed: |
February 9, 2009 |
Current U.S.
Class: |
123/90.17 ;
464/160 |
Current CPC
Class: |
F01L 1/352 20130101;
F01L 1/024 20130101; F01L 2820/032 20130101; F01L 1/022
20130101 |
Class at
Publication: |
123/90.17 ;
464/160 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 8, 2008 |
JP |
2008-29433 |
Claims
1. A valve timing adjusting apparatus for adjusting timing of a
valve that is opened and closed by a camshaft through transmission
of an engine torque from a crankshaft of an the internal combustion
engine, the valve timing adjusting apparatus comprising: a
driving-side rotor that is rotatable synchronously with the
crankshaft by transmission of the engine torque through an annular
torque transmission member that extends between the crankshaft and
the driving-side rotor, wherein: the driving-side rotor includes a
peripheral wall member and a bottom wall member; and the bottom
wall member is fastened coaxially to the peripheral wall member and
connected with the torque transmission member; a driven-side rotor
that is received in the driving-side rotor and rotatable
synchronously with the camshaft; a sun gear that is fastened
coaxially to the peripheral wall member and rotatable integrally
with the driving-side rotor; and a planet gear that is in mesh with
the sun gear and moves epicyclically with respect to the sun gear
such that a relative phase between the driving-side rotor and the
driven-side rotor is changed, wherein: one of the sun gear and the
bottom wall member is fitted with an inner peripheral side of one
axial end portion of the peripheral wall member; and the other one
of the sun gear and the bottom wall member is fitted with an outer
peripheral side of the other axial end portion of the peripheral
wall member.
2. The valve timing adjusting apparatus according to claim 1,
wherein: the one of the sun gear and the bottom wall member is
press fitted with the inner peripheral side of the one axial end
portion of the peripheral wall member such that the one of the sun
gear and the bottom wall member is press fitted into the one axial
end portion; and the other one of the sun gear and the bottom wall
member is press fitted with the outer peripheral side of the other
axial end portion of the peripheral wall member such that the other
axial end portion is press fitted into the other one of the sun
gear and the bottom wall member.
3. The valve timing adjusting apparatus according to claim 1,
wherein: the driving-side rotor includes at least one fastening
member that fastens the peripheral wall member with the bottom wall
member; and the at least one fastening member fastens the sun gear
together with the peripheral wall member and the bottom wall
member.
4. The valve timing adjusting apparatus according to claim 1,
wherein: the bottom wall member is a sprocket having a plurality of
teeth that are engaged with the torque transmission member.
5. The valve timing adjusting apparatus according to claim 1,
wherein: the peripheral wall member includes a stopper surface at
an inner peripheral surface of the peripheral wall member; and the
stopper surface has a step surface shape that contacts the
driven-side rotor in a rotational direction such that change of the
relative phase is limited.
6. The valve timing adjusting apparatus according to claim 1,
wherein: the peripheral wall member has a tubular shape extending
straight in a longitudinal direction of the peripheral wall
member.
7. The valve timing adjusting apparatus according to claim 1,
wherein: each of the peripheral wall member and the bottom wall
member is formed by cutting a corresponding near net shape molded
body.
8. A valve timing adjusting apparatus for adjusting timing of a
valve that is opened and closed by a camshaft through transmission
of an engine torque from a crankshaft of an the internal combustion
engine, the valve timing adjusting apparatus comprising: a
driving-side rotor that is rotatable synchronously with the
crankshaft, wherein: the driving-side rotor includes a peripheral
wall member and a bottom wall member that is fastened coaxially to
the peripheral wall member; the bottom wall member is coupled with
a torque transmission member that extends between the crankshaft
and the driving-side rotor; and the bottom wall member receives the
engine torque transmitted through the torque transmission member; a
driven-side rotor that is received in the driving-side rotor and
rotatable synchronously with the camshaft; a sun gear that is
fastened coaxially to the peripheral wall member and rotatable
integrally with the driving-side rotor; and a planet gear that is
in mesh with the sun gear and moves epicyclically with respect to
the sun gear such that a relative phase between the driving-side
rotor and the driven-side rotor is changed, wherein: the peripheral
wall member includes one axial end portion that extends in a
longitudinal direction of the driving-side rotor, the one axial end
portion defining a first fitting hole therein that has a radially
inner contact surface; one of the sun gear and the bottom wall
member has a first fitting projection that extends in the
longitudinal direction of the driving-side rotor, the first fitting
projection having a radially outer contact surface; the first
fitting projection is fitted into the first fitting hole such that
the radially inner contact surface of the first fitting hole is
opposed to the radially outer contact surface of the first fitting
projection in a radial direction of the driving-side rotor; the
peripheral wall member includes the other axial end portion that
serves as a second fitting projection extending in the longitudinal
direction of the driving-side rotor, the second fitting projection
having a radially outer contact surface; the other one of the sun
gear and the bottom wall member defines a second fitting hole
therein that has a radially inner contact surface; and the second
fitting projection is fitted into the second fitting hole such that
the radially inner contact surface of the second fitting hole is
opposed to the radially outer contact surface of the second fitting
projection in the radial direction of the driving-side rotor.
9. The valve timing adjusting apparatus according to claim 8,
wherein: the first fitting projection is press fitted into the
first fitting hole; and the second fitting projection is press
fitted into the second fitting hole.
10. The valve timing adjusting apparatus according to claim 8,
wherein: the driving-side rotor includes at least one fastening
member that fastens the peripheral wall member with the bottom wall
member; and the at least one fastening member fastens the sun gear
together with the peripheral wall member and the bottom wall
member.
11. The valve timing adjusting apparatus according to claim 8,
wherein: the bottom wall member is a sprocket having a plurality of
teeth that are engaged with the torque transmission member.
12. The valve timing adjusting apparatus according to claim 8,
wherein: the peripheral wall member includes a stopper surface at
an inner peripheral surface of the peripheral wall member; and the
stopper surface has a step surface shape that contacts the
driven-side rotor in a rotational direction such that change of the
relative phase is limited.
13. The valve timing adjusting apparatus according to claim 8,
wherein: the peripheral wall member has a tubular shape extending
straight from the one axial end portion to the other axial end
portion in a longitudinal direction of the peripheral wall
member.
14. The valve timing adjusting apparatus according to claim 8,
wherein: each of the peripheral wall member and the bottom wall
member is formed by cutting a corresponding near net shape molded
body.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on and incorporates herein by
reference Japanese Patent Application No. 2008-29433 filed on Feb.
8, 2008.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a valve timing adjusting
apparatus capable of adjusting timing of a valve that is opened and
closed by a camshaft through transmission of an engine torque from
a crankshaft of an internal combustion engine.
[0004] 2. Description of Related Art
[0005] A conventional valve timing adjusting apparatus is known to
obtain a required valve timing by changing a relative phase
relation between a driving-side rotor and a driven-side rotor. In
the above, the driving-side rotor is rotatable synchronously with a
crankshaft, and the driven-side rotor is rotatable synchronously
with a camshaft. The above relative phase relation between the
rotors is named as an "inter-rotor phase" in the present
specification.
[0006] For example, FIG. 10 in JP-A-2007-255412 (corresponding to
FIG. 10 in US20070199531) discloses a valve timing adjusting
apparatus that has a driving-side rotor, a driven-side rotor having
a planet gear, and a sun gear. The driving-side rotor has a hollow
cylindrical shape with a bottom and receives the driven-side rotor
within a peripheral wall portion thereof. The sun gear is fixed
coaxially with the driving-side rotor on a side of the driving-side
rotor opposite from the bottom wall portion of the driving-side
rotor. Also, the sun gear is rotatable integrally with the
driving-side rotor. The planet gear of the driven-side rotor is in
mesh with the sun gear. In the above configuration, an epicyclic
motion of the planet gear changes the inter-rotor phase between the
rotors.
[0007] In the apparatus shown in JP-A-2007-255412 (FIG. 10), the
driving-side rotor serving as a sprocket is engaged with or is in
mesh with an annular timing chain that is engaged with the
crankshaft such that the timing chain extends between and drivingly
connects the driving-side rotor and the crankshaft. As a result,
the timing chain transmits an engine torque between the
driving-side rotor and the crankshaft. The driving-side rotor has a
tubular shape with a bottom, and a bottom wall portion of the
driving-side rotor has multiple teeth that are engaged with the
timing chain. As a result, the driving-side rotor has a complex
shape as a whole. In order to produce the above complicated
driving-side rotor, for example, it is required to perform a
complicated operation, such as extensively machining a
column-molded blank, and thereby productivity may deteriorate
disadvantageously.
[0008] In order to improve the productivity of the driving-side
rotor, the inventors of the present invention have studied a
technique, in which the driving-side rotor is made of separate two
components (a peripheral wall portion and a bottom wall portion)
that are coaxially fixed with each other. The driving-side rotor
made as above has a tubular shape. Because each of the two
components are separate from one another in the formation process,
the formation of each component is effectively facilitated.
However, it is found that the bottom wall portion and the sun gear
may be displaced from each other when the engine torque is
transmitted thereto because of a certain configuration, in which
the sun gear, which is in mesh with the planet gear, and the bottom
wall portion, which is engaged with the timing chain, are coaxially
with each other with the peripheral wall portion interposed
therebetween. The above possible displacement of the bottom wall
portion and the sun gear may twist the peripheral wall portion
interposed therebetween, and thereby the peripheral wall portion
may deform in the radial direction. As a result, the unwanted
change of the inter-rotor phase between the rotors may occur, and
thereby the unwanted change in valve timing may occur
disadvantageously.
SUMMARY OF THE INVENTION
[0009] The present invention is made in view of the above
disadvantages. Thus, it is an objective of the present invention to
address at least one of the above disadvantages.
[0010] To achieve the objective of the present invention, there is
provided a valve timing adjusting apparatus for adjusting timing of
a valve that is opened and closed by a camshaft through
transmission of an engine torque from a crankshaft of an the
internal combustion engine, the valve timing adjusting apparatus
including a driving-side rotor, a driven-side rotor, a sun gear,
and a planet gear. The driving-side rotor is rotatable
synchronously with the crankshaft by transmission of the engine
torque through an annular torque transmission member that extends
between the crankshaft and the driving-side rotor. The driving-side
rotor includes a peripheral wail member and a bottom wall member.
The bottom wall member is fastened coaxially to the peripheral wall
member and connected with the torque transmission member. The
driven-side rotor is received in the driving-side rotor and
rotatable synchronously with the camshaft. The sun gear is fastened
coaxially to the peripheral wall member and rotatable integrally
with the driving-side rotor. The planet gear is in mesh with the
sun gear and moves epicyclically with respect to the sun gear such
that a relative phase between the driving-side rotor and the
driven-side rotor is changed. One of the sun gear and the bottom
wall member is fitted with an inner peripheral side of one axial
end portion of the peripheral wall member. The other one of the sun
gear and the bottom wall member is fitted with an outer peripheral
side of the other axial end portion of the peripheral wall
member.
[0011] To achieve the objective of the present invention, there is
also provided a valve timing adjusting apparatus for adjusting
timing of a valve that is opened and closed by a camshaft through
transmission of an engine torque from a crankshaft of an the
internal combustion engine, the valve timing adjusting apparatus
including a driving-side rotor, a driven-side rotor, a sun gear,
and a planet gear. The driving-side rotor is rotatable
synchronously with the crankshaft. The driving-side rotor includes
a peripheral wall member and a bottom wall member that is fastened
coaxially to the peripheral wall member. The bottom wall member is
coupled with a torque transmission member that extends between the
crankshaft and the driving-side rotor. The bottom wall member
receives the engine torque transmitted through the torque
transmission member. The driven-side rotor is received in the
driving-side rotor and rotatable synchronously with the camshaft.
The sun gear is fastened coaxially to the peripheral wall member
and rotatable integrally with the driving-side rotor. The planet
gear is in mesh with the sun near and moves epicyclically with
respect to the sun gear such that a relative phase between the
driving-side rotor and the driven-side rotor is changed. The
peripheral wall member includes one axial end portion that extends
in a longitudinal direction of the driving-side rotor, and the one
axial end portion defines a first fitting hole therein that has a
radially inner contact surface. One of the sun gear and the bottom
wall member has a first fitting projection that extends in the
longitudinal direction of the driving-side rotor, and the first
fitting projection has a radially outer contact surface. The first
fitting projection is fitted into the first fitting hole such that
the radially inner contact surface of the first fitting hole is
opposed to the radially outer contact surface of the first fitting
projection in a radial direction of the driving-side rotor. The
peripheral wall member includes the other axial end portion that
serves as a second fitting projection extending in the longitudinal
direction of the driving-side rotor, and the second fitting
projection has a radially outer contact surface. The other one of
the sun gear and the bottom wall member defines a second fitting
hole therein that has a radially inner contact surface. The second
fitting projection is fitted into the second fitting hole such that
the radially inner contact surface of the second fitting hole is
opposed to the radially outer contact surface of the second fitting
projection in the radial direction of the driving-side rotor
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention, together with additional objectives, features
and advantages thereof, will be best understood from the following
description, the appended claims and the accompanying drawings in
which:
[0013] FIG. 1 is a cross-sectional view taken along line I-I in
FIG. 2 illustrating a basic configuration of a valve timing
adjusting apparatus according to the first embodiment of the
present invention;
[0014] FIG. 2 is a cross-sectional view taken along line II-II in
FIG. 1;
[0015] FIG. 3 is a cross-sectional view taken along line III-III in
FIG. 1;
[0016] FIG. 4 is a cross-sectional view illustrating an enlarged
phase adjustment mechanism in FIG. 1;
[0017] FIG. 5 is a cross-sectional view illustrating an enlarged
phase adjustment mechanism of a valve timing adjusting apparatus
according to the second embodiment of the present invention;
and
[0018] FIG. 6 is a cross-sectional view illustrating a phase
adjustment mechanism of a valve timing adjusting apparatus
according to the third embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0019] Multiple embodiments of the present invention will be
described with reference to accompanying drawings. Note that,
components in one of the embodiments that are similar to components
in the other embodiment will be indicated by the same numerals, and
thereby the overlapped explanation thereof will be omitted.
First Embodiment
[0020] FIG. 1 shows a valve timing adjusting apparatus 1 according
to the first embodiment of the present invention. The valve timing
adjusting apparatus 1 is mounted on a vehicle, and more
specifically, the valve timing adjusting apparatus 1 is mounted on
a transmission system that transmits an engine torque to a camshaft
2 from a crankshaft (not shown) of an internal combustion engine.
It should be noted that in the present embodiment the camshaft 2
opens and closes an intake valve (not shown) that serves as a
"valve" of the internal combustion engine through transmission of
the engine torque, and thereby the valve timing adjusting apparatus
1 adjusts valve timing of the intake valve.
(Basic Configuration)
[0021] A basic configuration of the valve timing adjusting
apparatus 1 of the first embodiment will be described below. The
valve timing adjusting apparatus 1 includes an electric motor 4, an
energization control circuit unit 7, and a phase adjustment
mechanism 8.
[0022] The electric motor 4 is, for example, a brushless motor, and
includes a motor case 5 and a motor shaft 6. The motor case 5 is
fixed to a fixation part of an internal combustion engine, which is
immovable relative to the engine, and the motor shaft 6 is
supported by the motor case 5 rotatably in normal and reverse
directions. The energization control circuit unit 7 includes a
driver and a microcomputer that controls the driver. The
energization control circuit unit 7 is provided outside and/or
inside the motor case 5, and is electrically connected with the
electric motor 4. The energization control circuit unit 7 controls
energization of the motor 4 in order to rotate the motor shaft
6.
[0023] The phase adjustment mechanism 8 includes a driving-side
rotor 10, a sun gear 12, a driven-side rotor 20, a planet gear
carrier 40, and a planet gear 50.
[0024] As shown in FIGS. 1 to 3, the driving-side rotor 10 has a
hollow cylindrical shape with a bottom, and the sun gear 12 has a
hollow cylindrical shape with a bottom. The driving-side rotor 10
and the sun gear 12 are fixed coaxially with each other in a state
where opening portions of the driving-side rotor 10 and the sun
gear 12 overlap with each other in an axial direction. In the above
way, the driving-side rotor 10 and the sun gear 12 define
therebetween a reception space 14 that receives the other
components 20, 40, 50 of the phase adjustment mechanism 8.
[0025] The driving-side rotor 10 has multiple teeth 15 that are
arranged one after another in a rotational direction, and the
multiple teeth 15 projects radially outwardly. An annular timing
chain 16 is engaged with the teeth 15 of the driving-side rotor 10
and with multiple teeth (not shown) of the crankshaft, and thereby
the timing chain 16 extends between and drivingly connects the
driving-side rotor 10 and the crankshaft. The above coupling
enables the transmission of the engine torque of the crankshaft to
the driving-side rotor 10 through the timing chain 16 and causes
the driving-side rotor 10 to rotate integrally with the sun gear 12
and synchronously with the crankshaft. The rotational direction of
the driving-side rotor 10 and the sun gear 12 corresponds to a
clockwise direction in FIGS. 2, 3.
[0026] As shown in FIGS. 1, 2, the sun gear 12 includes a
driving-side internal gear 18 on a radially inner side of a
peripheral wall portion of the sun gear 12, and the driving-side
internal gear 18 defines an addendum circle located on a radially
inner side of a root circle.
[0027] As shown in FIGS. 1, 3, the driven-side rotor 20 has a
hollow cylindrical shape with a bottom, and is concentrically
fitted with the driving-side rotor 10 on an inner peripheral side
of the driving-side rotor 10. The driven-side rotor 20 has a
connection member 21 on a bottom wall portion of the driven-side
rotor 20, and the connection member 21 is coaxially coupled with
the camshaft 2 through a threaded member. The above coupling
enables the driven-side rotor 20 to rotate synchronously with the
camshaft 2 and to rotate with respect to the driving-side rotor 10.
The rotational direction of the driven-side rotor 20 corresponds to
the clockwise direction in FIG. 3 similar to the driving-side rotor
10.
[0028] The driven-side rotor 20 includes a driven-side internal
gear 22 on a radially inner side of the peripheral wall portion,
and the driven-side internal gear 22 defines an addendum circle on
a radially inner side of a root circle. The driven-side internal
gear 22 has an inner diameter smaller than an inner diameter of the
driving-side internal gear 18, and the number of teeth of the
driven-side internal gear 22 is smaller than the number of teeth of
the driving-side internal gear 18. The driven-side internal gear 22
is positioned away from the driving-side internal gear 18 in a
longitudinal direction.
[0029] As shown in FIGS. 1 to 3, the planet gear carrier 40
generally has a tubular shape and has an inner peripheral surface
that serves as an input portion 41. The input portion 41 is
concentrically provided relative to the rotors 10, 20 and the motor
shaft 6. The input portion 41 has a fitting groove 42 that is
configured to be fitted with a coupling joint 43. The coupling
joint 43 connects the motor shaft 6 with the planet gear carrier
40. The coupling enables the planet gear carrier 40 to rotate
together with the motor shaft 6, and also to rotate with respect to
the driving-side rotor 10 and the sun gear 12.
[0030] The planet gear carrier 40 has an outer peripheral surface,
which is eccentric with respect to the input portion 41, and which
serves as an eccentric portion 44. The eccentric portion 44 is
concentrically fitted into a central hole 51 of the planet gear 50
through a bearing 45. Due to the above configuration, the eccentric
portion 44 supports the planet gear 50 in order to enable an
epicyclic motion of the planet gear 50 in accordance with a
rotation of the planet gear carrier 40 with respect to the sun gear
12. In the epicyclic motion of the present embodiment, the planet
gear 50 rotates about an eccentric axis of the eccentric portion
44, and also the planet gear 50 revolves relative to the sun gear
12 in the rotational direction of the planet gear carrier 40. In
other words, the planet gear 50 rotates epicyclically with respect
to the sun gear 12.
[0031] The planet gear 50 has a shouldered hollow cylindrical
shape, and more specifically, the planet gear 50 has a
large-diameter section and a small-diameter section that has a
diameter smaller than that of the large-diameter section. Thus, the
planet gear 50 defines a driving-side external gear 52 at the
large-diameter section and a driven-side external gear 54 at the
small-diameter section. Each of the driving-side external gear 52
and driven-side external gear 54 defines an addendum circle on a
radially outer side of a root circle. The driving-side external
gear 52 has the number of teeth that is smaller than the number of
teeth of the driving-side internal gear 18 by a certain number.
Also, the number of teeth of the driven-side external gear 54 is
smaller than the number of teeth of the driven-side internal gear
22 by the number identical with the above certain number. The
driving-side external gear 52 is provided on a radially inner side
of the driving-side internal gear 18 and in mesh with the
driving-side internal gear 18 Also, the driven-side external gear
54 is displaced from the driving-side external gear 52 toward the
connection member 21. The driven-side external gear 54 is provided
on a radially inner side of the driven-side internal gear 22 and in
mesh with the driven-side internal gear 22.
[0032] The phase adjustment mechanism 8 gears to the rotors 10, 20
as above and adjusts an inter-rotor phase, which is a relative
phase relation of the driven-side rotor 20 with respect to the
driving-side rotor 10, in accordance with a rotational state of the
motor shaft 6.
[0033] Specifically, in a case, where the planet gear carrier 40 is
not rotated with respect to the sun gear 12 because the motor shaft
6 rotates at the speed that is equivalent to the rotational speed
of the driving-side rotor 10, the epicyclic motion of the planet
gear 50 is not caused. Accordingly, the planet gear 50 rotates
together with the rotors 10, 20. As a result, the inter-rotor phase
is not changed, and accordingly, the valve timing is held.
[0034] In contrast, in a case, where the planet gear carrier 40
rotates relative to the sun gear 12 in an advance direction because
the motor shaft 6 rotates at a speed higher than the rotational
speed of the driving-side rotor 10, the epicyclic motion of the
planet gear 50 is caused. Accordingly, the driven-side rotor 20
rotates relative to the driving-side rotor 10 in the advance
direction. As a result, the inter-rotor phase is changed in the
advance direction, and accordingly the valve timing is
advanced.
[0035] Also, in another case, where the planet gear carrier 40
rotates relative to the sun gear 12 in a retard direction because
the motor shaft 6 rotates in a reverse direction or rotates at a
speed lower than the rotational speed of the driving-side rotor 10,
the epicyclic motion of the planet gear 50 is caused. Accordingly,
the driven-side rotor 20 rotates relative to the driving-side rotor
10 in the retard direction. As a result, the inter-rotor phase is
changed in the retard direction, and accordingly the valve timing
is retarded.
(Characteristic Part)
[0036] Characteristic part of the first embodiment will be
described.
(Fastening Structure of Driving-Side Rotor and Sun Gear)
[0037] As shown in FIG. 1, the driving-side rotor 10 includes a
metal bottom wall member 100, a metal peripheral wall member 110,
and threaded members 120.
[0038] As shown in FIG. 4, the bottom wall member 100 has an
annular plate shape and has a thick wall. The bottom wall member
100 constitutes a sprocket that has the teeth 15 engaged with the
timing chain 16. The bottom wall member 100 has a fitting hole 102
defined at a radial center thereof. The fitting hole 102 is a hole
having a bottom surface 104 and opens at one axial end surface 101
of the bottom wall member 100. Also, the bottom wall member 100 has
a through hole 105 defined at the radial center thereof. The
through hole 105 opens at the other axial end surface 103 of the
bottom wall member 100 and at the bottom surface 104 of the fitting
hole 102 and receives the camshaft 2.
[0039] The peripheral wall member 110 has a shouldered or stepped
hollow cylindrical shape that has a different diameter at a
different position in the longitudinal direction. The peripheral
wall member 110 has one axial end portion 111 having a smaller
diameter than the other part of the peripheral wall member 110, and
the one axial end portion 111 is press-fitted into the fitting hole
102 of the bottom wall member 100. The one axial end portion 111
has a radially outer contact surface, and the fitting hole 102 has
a radially inner contact surface. Thus, in a state, where the one
axial end portion 111 is press-fitted into the fitting hole 102 of
the bottom wall member 100, the radially inner contact surface of
the fitting hole 102 is opposed to the radially outer contact
surface of the axial end portion 111 in a radial direction of the
driving-side rotor 10. In other words, the one axial end portion
111 of the peripheral wall member 110 has an outer peripheral side
that is press-fitted with the bottom wall member 100. Due to the
above fitting, the peripheral wall member 110 defines therein a
space 14a, which is a part of the reception space 14, as shown in
FIGS. 3, 4. The space 14a receives an entirety of the driven-side
rotor 20 and part of each of the planet gear carrier 40 and the
planet gear 50. Also, as shown in FIGS. 2, 4, the peripheral wall
member 110 has a fitting hole 114 defined at a radial center
thereof. The fitting hole 114 is a hole with a bottom and opens at
an end surface 113 of the other axial end portion 112. The other
axial end portion 112 has a diameter greater than that of the one
axial end portion 111, and is located on a side of the peripheral
wall member 110 opposite from the one axial end portion 111 in the
longitudinal direction.
[0040] As shown in FIGS. 3, 4, each of the threaded members 120 is
made of a metal bolt, and the threaded members 120 are provided at
multiple positions. The bottom wall member 100 and the peripheral
wall member 110 are arranged coaxial with each other, and the
threaded members 120 are provided at predetermined positions of the
wall members 100, 110 in the rotational direction in order to
fasten the bottom wall member 100 with the peripheral wall member
110 in the above coaxial state. As above, the bottom wall member
100, the peripheral wall member 110, and the threaded members 120
constitute the driving-side rotor 10 having a hollow cylindrical
shape with a bottom.
[0041] As shown in FIGS. 2, 4, the sun gear 12 includes a fitting
projection 130 having a hollow cylindrical shape at an opening
portion thereof and the fitting projection 130 is press-fitted into
the fitting hole 114 of the peripheral wall member 110. The fitting
projection 130 has a radially outer contact surface, and the
fitting hole 114 has a radially inner contact surface. Thus, in a
state, where the fitting projection 130 of the sun gear 12 is
press-fitted into the fitting hole 114 of the other axial end
portion 112 of the peripheral wall member 110, the radially inner
contact surface of the fitting hole 114 is opposed to the radially
outer contact surface of the fitting projection 130 in the radial
direction of the driving-side rotor 10. In other words, the sun
gear 12 is press-fitted with an inner peripheral side of the other
axial end portion 112 of the peripheral wall member 110. Due to the
above fitting, the sun gear 12 defines a space 14b, which is
another part of the reception space 14, at an inner peripheral side
of the driving-side internal gear 18. The space 14b is configured
to receive the remaining of each of the planet gear carrier 40 and
the planet gear 50, which is not received by the space 14a. The sun
gear 12 is fastened together with the bottom wall member 100 and
the peripheral wall member 110 by the multiple threaded members 120
at multiple positions in the rotational direction. Thus, the sun
gear 12 is fastened coaxially with the peripheral wall member 110.
In other words, in the present embodiment, the sun gear 12 is
arranged coaxially with the bottom wall member 100, and the
peripheral wall member 110 is provided between the sun gear 12 and
the bottom wall member 100 in the longitudinal direction.
(Stopper Structure)
[0042] As shown in FIG. 3, the peripheral wall member 110 is
provided with advance stopper surfaces 140 to 143 extending from an
inner peripheral surface 116 of the peripheral wall member 110 in a
generally radially inward direction and arranged circumferentially
or in the rotational direction one after another at multiple
positions of the inner peripheral surface 116. Thus, each of the
advance stopper surfaces 140 to 143 has a step surface shape as
shown in FIG. 3. Also, the peripheral wall member 110 has retard
stopper surfaces 150 to 153 extending from the inner peripheral
surface 116 in the generally radially inward direction and arranged
in the rotational direction one after another at multiple positions
of the inner peripheral surface 116. Thus, each of the retard
stopper surfaces 150 to 153 has a step surface shape. Each of the
retard stopper surfaces 150 to 153 is spaced apart in the
rotational direction from a corresponding one of the advance
stopper surfaces 140 to 143. As shown in FIG. 3, the retard stopper
surface 150 is opposed to the advance stopper surface 140, the
retard stopper surface 151 is opposed to the advance stopper
surface 141, the retard stopper surface 152 is opposed to the
advance stopper surface 142, and the retard stopper surface 153 is
opposed to the advance stopper surface 143.
[0043] As shown in FIGS. 1, 3, the driven-side rotor 20 is provided
with stopper projections 160 to 163 that projects from the
peripheral wall portion of the driven-side rotor 20 in the radially
outward direction of the driven-side internal gear 22. Also, the
stopper projections 160 to 163 are arranged at multiple positions
of the peripheral wall portion in the rotational direction. Each of
the stopper projections 160 to 163 is positioned between the
corresponding one of pairs of the advance stopper surfaces 140 to
143 and the retard stopper surfaces 150 to 153. More specifically,
the stopper projection 160 is provided between the advance stopper
surface 140 and the retard stopper surface 150, for example.
[0044] In the present embodiment, in a state, where the stopper
projection 160 contacts the advance stopper surface 140 that is
positioned on an advance side of the stopper projection 160 in the
rotational direction, the driven-side rotor 20 is limited from
rotating relative to the driving-side rotor 10 in the advance
direction. In other words, the change of the inter-rotor phase in
the advance direction is restricted. In contrast, in a state, where
the stopper projection 160 contacts the retard stopper surface 150
that is positioned on a retard side of the stopper projection 160
in the rotational direction, the driven-side rotor 20 is limited
from rotating relative to the driving-side rotor 10 in the retard
direction. In other words, the change of the inter-rotor phase in
the retard direction is restricted. As above, the group of the
advance stopper surface 140, the retard stopper surface 150, and
the stopper projection 160 function as a phase change restriction
in a normal operation.
[0045] In an abnormal case, where there is a failure in the above
normal group of components 140, 150, 160, a first alternative group
including the stopper surfaces 141, 151 and the stopper projection
161, a second alternative group including the stopper surfaces 142,
152 and the stopper projection 162, and a third alternative group
including the stopper surfaces 143, 153 and the stopper projection
163 may alternatively function as the above phase change
restriction of the normal group.
(Method for Manufacturing Bottom Wall Member and Peripheral Wall
Member)
[0046] Each of the bottom wall member 100 and the peripheral wall
member 110 of the driving-side rotor 10 is formed by a cutting
operation (machining operation) of a molded body made through a
near net shape technique.
[0047] More specifically, in the formation process of the bottom
wall member 100, firstly, a powder metallurgy material is molded
and sintered such that the sintered body has a annular plate shape
similar to the final shape of the finished product of the bottom
wall member 100. As above, a bottom wall member blank is formed to
serve as the near net shape molded body. Then, the cutting
operation is performed to a peripheral surface and a end surface of
the bottom wall member blank, and thereby the bottom wall member
100 having the multiple teeth 15 and the holes 102, 105 is
completed.
[0048] Also, in the forming process of the peripheral wall member
110, firstly, a powder metallurgy material is molded and sintered
such that the sintered body has a hollow cylindrical shape similar
to the final shape of the finished product of the peripheral wall
member 110. As above, a peripheral wall member blank is formed to
serve as the near net shape molded body. Then, a peripheral surface
and an end surface of the peripheral wall member blank is cut, and
thereby the peripheral wall member 110 having the hole 114 and the
stopper surfaces 140 to 143, 150 to 153 is completed.
[0049] The powder metallurgy material used for forming the bottom
wall member 100 and the peripheral wall member 110 may be selected
from various metal materials in accordance with specifications. For
example, in the present embodiment, alloy steel powder including
copper is employed as the powder metallurgy material. Also, in the
present embodiment, the sun gear 12, the driven-side rotor 20, the
planet gear carrier 40, and the planet gear 50 may be also formed
by the cutting operation of the near net shape molded body similar
to the case for the bottom wall member 100 and the peripheral wall
member 110.
[0050] In the above described first embodiment, the bottom wall
member 100 and the peripheral wall member 110 are separate bodies
and are fastened to each other to constitute the driving-side rotor
10. It is possible to easily form the bottom wall member 100 and
the peripheral wall member 110 by the cutting of the near net shape
molded body. More specifically, the stopper surfaces 140 to 143,
150 to 153 having the step surface shape are provided on the inner
peripheral surface 116 of the peripheral wall member 110. Because
the peripheral wall member 110 is separate from the bottom wall
member 100, the above stopper surfaces 140 to 143, 150 to 153 are
further easily made by the cutting operation. Furthermore, in the
first embodiment, the threaded member 120 fastens the bottom wall
member 100 with the peripheral wall member 110 in order to form the
driving-side rotor 10. Because the above threaded member 120 is
also used to fasten the sun gear 12 with the driving-side rotor 10,
a fastening structure of the driving-side rotor 10 and the sun gear
12 is easily realized or obtained. In the first embodiment,
productivity of the valve timing adjusting apparatus 1 is
effectively improved.
[0051] Also, according to the first embodiment, the sun gear 12,
which is in mesh with the planet gear 50, and the bottom wall
member 100, which is engaged with the timing chain 16 transmitting
the engine torque, are provided coaxially with each other on
opposite axial sides of the peripheral wall member 110. As a
result, the sun gear 12 may be displaced relative to the bottom
wall member 100 while transmitting the engine torque in the
conventional art. However, the sun gear 12 is fitted with the inner
peripheral side of the other axial end portion 112 of the
peripheral wall member 110, and the bottom wall member 100 is
fitted with the outer peripheral side of the one axial end portion
111 of the peripheral wall member 110. In other words, the sun gear
12 is fitted into the other axial end portion 112, and the one
axial end portion 111 is fitted into the bottom wall member 100. As
a result, even when the peripheral wall member 110 receives a
torsional force caused by the displacement of the sun gear 12
relative to the bottom wall member 100, one of the axial end
portions 111, 112 is urged radially inwardly by the other one of
the axial end portions 111, 112, and thereby the peripheral wall
member 110 is limited from deforming in the radial direction.
Furthermore, in the first embodiment, boundary surfaces between the
sun gear 12 and the peripheral wall member 110 are press fitted
with each other. Also, the other boundary surfaces between the
bottom wall member 100 and the peripheral wall member 110 are press
fitted with each other. Due to the above configuration, clearances
that otherwise allow the deformation of the axial end portions 112,
111 of the peripheral wall member 110 in the radial direction are
substantially eliminated. Still more, in the first embodiment,
because the components 12, 100, 110 are fastened to each other
commonly by the threaded members 120, torsion of the peripheral
wall member 110 cased by the displacement of the components 12, 100
is restricted by the threaded members 120. According to the first
embodiment, even in a condition, where the displacement of the
components 12, 100 from each other is prone to occur because of the
engine torque highly efficiently transmitted through the multiple
teeth 15 engaged with the timing chain 16, the unwanted change of
the inter-rotor phase caused by the deformation of the peripheral
wall member 110 is effectively restricted as above, and thereby
accuracy in adjustment of the valve timing is effectively
improved.
[0052] In addition to the above, according to the first embodiment,
when the stopper projection 160 of the driven-side rotor 20
contacts, in the rotational direction, one of the stopper surfaces
140, 150 defined on the inner peripheral surface 116 of the
peripheral wall member 110, deformation of the peripheral wall
member 110 in the radial direction may occur in the conventional
art. However, in the first embodiment, the peripheral wall member
110 is limited from deforming in the radial direction as above, and
thereby even when the stopper projection 160 contacts either one of
the stopper surfaces 140, 150, the unwanted change of the
inter-rotor phase is restricted. As a result, accuracy in
adjustment of the valve timing is effectively improved.
[0053] It should be noted that in the first embodiment, the timing
chain 16 serves as a "torque transmission member", and the threaded
member 120 serves as a "fastening member". The fitting hole 114
serves as "first fitting hole", and the fitting projection 130
serves as "first fitting projection". Also, the fitting hole 102
serves as "second fitting hole", and the axial end portion 111
serves as "second fitting projection".
Second Embodiment
[0054] As shown in FIG. 5, the second embodiment of the present
invention is modification of the first embodiment. In the second
embodiment, a metal bottom wall member 2100 constituting a
driving-side rotor 2010 includes a fitting projection 2102 instead
of the fitting hole 102. The fitting projection 2102 has a hollow
cylindrical shape defining therein a central hole. The central hole
corresponds to a part of the through hole 105.
[0055] Also, a metal peripheral wall member 2110 constituting the
driving-side rotor 2010 has a shouldered or stepped hollow
cylindrical shape. The shouldered hollow cylindrical shape has a
different diameter at a different position of the shouldered hollow
cylindrical shape in the longitudinal direction. The peripheral
wall member 2110 has one axial end portion 2111 and the other axial
end portion 2112, and the one axial end portion 2111 has a diameter
greater than that of the other axial end portion 2112. The
peripheral wall member 2110 defines a fitting hole 2114 with a
bottom at a generally central part thereof, and the fitting hole
2114 opens at an end surface 2113 of the one axial end portion
2111. The fitting projection 2102 of the bottom wall member 2100 is
press-fitted into the fitting hole 2114. In other words, the bottom
wall member 2100 is press-fitted with an inner peripheral side of
the one axial end portion 2111 of the peripheral wall member
2110.
[0056] A sun gear 2012 defines a fitting hole 2014 with a bottom at
a generally central part thereof. The fitting hole 2014 opens at
one end surface 2013 of the sun gear 2012. The fitting hole 2014 is
press-fitted with the other axial end portion 2112 of the
peripheral wall member 2110. In other words, the sun gear 2012 is
press-fitted with an outer peripheral side of the other axial end
portion 2112 of the peripheral wall member 2110.
[0057] As above, in the second embodiment, in a state, where the
peripheral wall member 2110 is provided between the bottom wall
member 2100 and the sun gear 2012 in the longitudinal direction,
the above components 2012, 2100, 2110 are fastened coaxial with
each other by the threaded member 120 of the driving-side rotor
2010. Thus, the above components 2012, 2100, 2110 are integral with
each other. The bottom wall member 2100 is fitted with the inner
peripheral side of the one axial end portion 2111 of the peripheral
wall member 2110, and the sun gear 2012 is fitted with the outer
peripheral side of the other axial end portion 2112 of the
peripheral wall member 2110. Even when the peripheral wall member
2110 receives a torsion force caused by the components 2100, 2012
that tend to be displaced from each other, the peripheral wall
member 2110 is limited from deforming in the radial direction due
to the mechanism similar to the first embodiment. Also, because the
boundary surfaces of the components are pressed fitted with each
other as above, a clearance that otherwise enables the deformation
of the peripheral wall member 2110 is substantially eliminated
similar to the first embodiment. Also, the threaded member 120 is
capable of restricting the twist of the peripheral wall member 2110
similar to the first embodiment. As a result, also in the second
embodiment, the unwanted change of the inter-rotor phase caused by
deformation of the peripheral wall member 2110 is limited, and
thereby it is possible to accurately adjust the valve timing. In
addition to the above, in the second embodiment, the bottom wall
member 2100 and the peripheral wall member 2110 are separately
formed by the cutting operation of cutting the near net shape
molded body similar to the first embodiment. As a result, the
extensive cutting operation is effectively avoided, and thereby
productivity is effectively improved. In the present embodiment,
the fitting projection 2102 serves as "first fitting projection",
and the fitting hole 2114 serves as "first fitting hole". Also, the
axial end portion 2112 serves as "second fitting projection", and
the fitting hole 2014 serves as "second fitting hole".
Third Embodiment
[0058] As shown in FIG. 6, the third embodiment of the present
invention is modification of the second embodiment. In the third
embodiment, a metal peripheral wall member 3110 constituting a
driving-side rotor 3010 has a straight hollow cylindrical shape
that has a substantially constant diameter over a length or in a
longitudinal direction of the driving-side rotor 3010. In other
words, the peripheral wall member 3110 has a hollow cylindrical
shape extending straight in the longitudinal direction of the
peripheral wall member 3110. It should be noted that the peripheral
wall member 3110 has the stopper surfaces 140 to 143, 150 to 153
(not shown) at an inner peripheral surface of the peripheral wall
member 3110, and each of the stopper surfaces 140 to 143, 150 to
153 has a step surface shape. In the present embodiment, for
example, each of the above stopper surfaces 140 to 143, 150 to 153
has a shape that extends straight in the longitudinal direction
from one axial end to the other axial end of each stopper surface.
Also, the inner peripheral surface between the adjacent stopper
surfaces has a shape that extends straight in the longitudinal
direction from one axial end to the other axial end of the inner
peripheral surface. Thus, the driving-side rotor 3010 extends
straight from the one axial end portion 2111 to the other axial end
portion 2112 in the longitudinal direction of the driving-side
rotor 3010.
[0059] According to the peripheral wall member 3110 having the
above straight shape, it is more easy to execute the near net shape
molding operation for forming the peripheral wall member blank and
the cutting operation of cutting the peripheral wall member blank
compared with the case of molding or machining the shouldered
member bank. As a result, productivity is substantially effectively
improved.
Other Embodiment
[0060] Although the multiple embodiments of the present invention
have been described as above, the interpretation of the present
invention is not limited to the above embodiments. Thus, the
present invention is applicable to various embodiments provided
that the various embodiments do not deviate from the gist of the
present invention.
[0061] More specifically, "torque transmission member" that
transmits the engine torque to the driving-side the rotors 10,
2010, 3010 may employ, for example, a timing belt that is engaged
with the bottom wall member 100, 2100 and with the multiple teeth
15, in place of the timing chain 16.
[0062] In place of the above described press fitting, the fitting
of the bottom wall member 100, 2100 with the peripheral wall member
110, 2110, 3110, and the fitting of the sun gear 12, 2012 with the
peripheral wall member 110, 2110, 3110 may be realized even when
the boundary surfaces of the above components are fitted with each
other with a clearance defined therebetween. Also, at least the
bottom wall member 100, 2100 and the peripheral wall member 110,
2110, 3110 may be formed by cutting a alternative near net shape
molded body formed by the other process other than the sintering of
the powder metallurgy material. For example, the alternative near
net shape molded body may be alternatively formed by forging a
metal material.
[0063] The "fastening member" that fastens at least the bottom wall
member 100, 2100 and the peripheral wall member 110, 2110, 3110 may
alternatively employ, for example, a rivet, or a pin in place of
the threaded member 120. Also, the sun gear 12, 2012 may be
alternatively fastened to the peripheral wall member 110, 2110,
3110 by another "fastening member" in addition to the "fastening
member" that fastens the bottom wall member 100, 2100 with the
peripheral wall member 110, 2110, 3110.
[0064] In the above, the planet gear 50 gears to the sun gear 12,
2012 and to the gear 22 of the driven-side rotor 20 in the phase
adjustment mechanism 8. However, the phase adjustment mechanism 8
may alternatively have another configuration, in which, an
alternative planet gear gears only to a sun gear that is fastened
to the driving-side the rotors 10, 2010, 3010, for example. In the
above alternative case, the driven-side rotor 20 is rotated
relative to the driving-side the rotors 10, 2010, 3010 in
accordance with the epicyclic motion of the alternative planet
gear. Also, the sun gear that is fastened to the driving-side the
rotors 10, 2010, 3010 is meshed with the planet gear through the
internal gear 18 as above. However, the sun gear may alternatively
be meshed with the external gear of the planet gear.
[0065] In the above embodiments, the apparatus adjusts valve timing
of the intake valve. However, the present invention may be
applicable to an apparatus that adjusts valve timing of an exhaust
valve serving as a "valve" and to an apparatus that adjusts valve
timing of both the intake valve and the exhaust valve.
[0066] Additional advantages and modifications will readily occur
to those skilled in the art. The invention in its broader terms is
therefore not limited to the specific details, representative
apparatus, and illustrative examples shown and described.
* * * * *