US2010064997A1PendingUtilityA1
Continuous camshaft phase shifting apparatus
Est. expirySep 19, 2026(~0.1 yrs left)· nominal 20-yr term from priority
Inventors:Xiaolan Ai
F01L 1/352F01L 1/344F02D 13/02
41
PatentIndex Score
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Cited by
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References
0
Claims
Abstract
A phase shift mechanism (A) for controlling a phase shift angle between a camshaft ( 12 ) and a drive ( 10 ) comprises a planetary gear train ( 20 ). The planetary gear train ( 20 ) has first and second planet gears ( 34, 26 ) that are united to rotate about common axis at the same angular velocity, and a carrier ( 32 ) which includes a first planet bearing ( 62 ) and a second planet bearing ( 64 ) on which the united first and second planet gears ( 34, 36 ) respectively rotate and a locking mechanism ( 24 ) carried by the carrier ( 32 ) for locking the planetary gear train ( 20 ) in a locked condition by preventing the planet gears ( 34, 36 ) from rotating relative to the carrier ( 32 ) such that the phase shift angle remains the same and the output shaft 26 rotates with the input shaft ( 18 ) at the same angular velocity.
Claims
exact text as granted — not AI-modified1 . In an internal combustion engine including a camshaft and a drive for the camshaft, a phase shift mechanism located between the drive and the camshaft for controlling a phase shift angle between the camshaft and the drive, the phase shift mechanism comprising:
an input shaft coupled to the drive; an output shaft coupled to the camshaft; a planetary gear train co-axially aligned around the input shaft and the output shaft, the planetary gear train having an input sun gear coupled to the input shaft, an output sun gear coupled to the output shaft, the planetary gear train further having first and second planet gears that engage the input and output sun gears, respectively, and are united to rotate about a common axis at the same angular velocity, and having a carrier with a first planet bearing and a second planet bearing on which the united first and second planet gears respectively rotate; and a locking mechanism for locking the planetary gear train in a locked condition by preventing the planet gears from rotating relative to the carrier to rotate the input sun gear, the output sun gear and the carrier as a unit such that the phase shift angle for the output shaft with respect to the input shaft remains the same and the output shaft rotates with the input shaft at the same angular velocity.
2 . The phase shifting mechanism according to claim 1 wherein the locking mechanism comprises friction torques caused by friction between the first planet gear and the first planet bearing and between the second planet gear and the second planet bearing.
3 . The phase shift mechanism according to claim 2 further comprising an electric machine coupled to the carrier, the electric machine configured to apply a torque to the planetary gear train for overcoming the friction torques enabling the carrier to rotate relative to at least one of the input sun gear and the output sun gear wherein the phase shift angle for the output shaft with respect to the input shaft changes so that the output shaft assumes a different angular velocity with respect to the input shaft.
4 . (canceled)
5 . The phase shifting mechanism according to claim 3 wherein the phase shift angle is a function of a gear ratio “SR 0 ” of the planetary gear train and wherein the gear ratio SR 0 is characterized by the equation:
SR
0
=
ω
S
2
-
ω
C
ω
S
1
-
ω
C
where
ω S1 =angular velocity of the input sun gear;
ω S2 =angular velocity of the output sun gear; and
ω C =angular velocity of the carrier.
6 . The phase shifting mechanism according to claim 5 wherein the change in the phase shift angle is characterized by the equation
Δ
θ
=
(
1
-
SR
0
)
∫
0
t
(
ω
S
1
-
ω
C
)
τ
.
7 . The phase shifting mechanism according to claim 4 wherein the gear ratio SR 0 is characterized by the equation:
SR
0
=
N
S
1
·
N
P
2
N
S
2
·
N
P
1
where
N S1 =the number of teeth for the input sun gear;
N S2 =the number of teeth for the output sun gear;
N P1 =the number of teeth for the first planet gear; and
N P2 =the number of teeth for the second planet gear.
8 . The phase shifting mechanism according to claim 7 wherein the change in the phase shift angle is characterized by the equation
Δ
θ
=
(
1
-
SR
0
)
∫
0
t
(
ω
S
1
-
ω
C
)
τ
.
9 . The phase shifting mechanism according to claim 6 wherein the torque applied by the electric machine to the planetary gear train comprises a resistant torque which unlocks the carrier by overcoming the torque caused by friction between the first planet gear and the first planet bearing and between the second planet gear and the second planet bearing to change the phase shift angle that the output shaft rotates with respect to the input shaft.
10 . The phase shifting mechanism according to claim 9 wherein a relationship between geometric parameters of the planetary gear train and the coefficients of friction between the first planet gear and the first planet bearing and between the second planet gear and the second planet bearing is characterized by the equation
μ
·
(
λ
1
·
tan
α
1
cos
β
1
+
λ
2
·
tan
α
2
cos
β
2
)
≥
i
1
·
1
-
SR
0
where
i
1
=
N
P
1
N
S
1
λ
1
=
r
1
R
S
1
λ
2
=
r
2
R
S
2
N P1 =the number of teeth for the first planet gear;
N S1 =the number of teeth for the input sun gear;
r 1 =the effective bore radius for planet support bearing;
r 2 =the effective bore radius for planet support bearing;
Rs 1 =pitch circle radius for the input sun gear;
R S2 =pitch circle radius for the output sun gear;
α 1 =pressure angle for the input sun gear and the first planet gear;
α 2 =pressure angle for the output sun gear and the second planet gear;
β 1 =half conical angle for planet support bearing;
β 2 =half conical angle for planet support bearing; and
μ=maximum available friction coefficient for the first and second planet bearings.
11 . The phase shifting mechanism according to claim 6 wherein continuous phase advancing occurs for the phase shift angle if SR 0 >1 and wherein continuous phase retarding occurs for the phase shift angle if SR 0 <1.
12 . (canceled)
13 . The phase shifting mechanism according to claim 6 wherein the torque applied by the electric machine to the planetary gear train comprises a driving torque which unlocks the carrier by overcoming the torques applied by the coefficients of friction between the first planet gear and the first planet bearing and between the second planet gear and the second planet bearing to change the phase shift angle that the output shaft rotates with respect to the input shaft.
14 . The phase shifting mechanism according to claim 13 wherein a relationship between geometric parameters of the planetary gear train and the coefficients of friction between the first planet gear and the first planet bearing and between the second planet gear and the second planet bearing is characterized by the equation
μ
·
(
λ
1
·
tan
α
1
cos
β
1
+
λ
2
·
tan
α
2
cos
β
2
)
≥
i
1
·
1
-
SR
0
where
i
1
=
N
P
1
N
S
1
λ
1
=
r
1
R
S
1
λ
2
=
r
2
R
S
2
N P1 =the number of teeth for the first planet gear;
N S1 =the number of teeth for the input sun gear;
r 1 =the effective bore radius for planet support bearing;
r 2 =the effective bore radius for planet support bearing;
Rs 1 =pitch circle radius for the input sun gear;
R S2 =pitch circle radius for the output sun gear;
α 1 =pressure angle for the input sun gear and the first planet gear;
α 2 =pressure angle for the output sun gear and the second planet gear;
β 1 =half conical angle for planet support bearing;
β 2 =half conical angle for planet support bearing; and
μ=maximum available friction coefficient for the first and second planet bearings.
15 . The phase shifting mechanism according to claim 13 wherein continuous phase retarding occurs for the phase shift angle if SR 0 >1 and wherein continuous phase advancing occurs for the phase shift angle if SR 0 <1.
16 . (canceled)
17 . The phase shifting mechanisms according to claim 3 further comprising a limiting device that rotatably couples the input sun gear with the output sun gear.
18 . The phase shifting mechanism according to claim 17 wherein the limiting device comprises a slot positioned on a face of the input sun gear and comprises an extension protruding from another face of the output sun gear such that the extension slidably engages with the slot.
19 . The phase shifting mechanism according to claim 17 wherein the limiting device comprises a slot positioned on a face of the input sun gear and comprises a key member protruding from another face of the output sun gear such that the key member slidably engages with the slot.
20 . The phase shifting mechanism according to claim 17 wherein the first and second planet gears are identically formed and are integrated as a single gear.
21 . (canceled)
22 . (canceled)
23 . (canceled)
24 . A method of controlling a phase shift angle between a camshaft and a drive of an internal combustion engine, the method comprising:
aligning a planetary gear train aligned around an input shaft coupled to the drive and around an output shaft coupled to the camshaft; locking the planetary gear train by the friction force to rotate an input sun gear, an output sun gear and a carrier of the planetary gear train as a unit, the input sun gear being coupled to the input shaft and the output sun gear being coupled to the output shaft such that the phase shift angle for the output shaft with respect to the input shaft remains the same and the output shaft rotates with the input shaft at the same angular velocity; and applying a torque to the planetary gear train for unlocking the friction force applied to the planetary gear train enabling the carrier to rotate relative to at least one of the input sun gear and the output sun gear wherein the phase shift angle for the output shaft with respect to the input shaft changes so that the output shaft assumes a different angular velocity with respect to the input shaft.
25 . The method according to claim 24 wherein applying the torque to the planetary gear train comprises applying a resistant torque which unlocks the carrier by overcoming the torque applied by the friction to change the phase shift angle such that the output shaft rotates with respect to the input shaft at a different angular velocity.
26 . The method according to claim 24 wherein applying the torque to the planetary gear train comprises applying a driving torque which unlocks the carrier by overcoming the torque applied by the friction to change the phase shift angle such that the output shaft rotates with respect to the input shaft at a different angular velocity.Join the waitlist — get patent alerts
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