Interrelated power delivery controls – including engine control – Transmission control – With clutch control
Reexamination Certificate
2000-05-02
2002-05-28
Marmor, Charles A (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
With clutch control
C477S080000, C477S084000
Reexamination Certificate
active
06394929
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a shift control apparatus and a shift control method of an automatic speed-change apparatus (transmission) of an automobile for automatically speed-changing a clutch disposed between an engine and the transmission, and for speed-changing a synchromesh mechanism of the transmission which changes a gear mesh mode thereof by an actuator, respectively.
2. Related Art
The above mentioned type automatic transmission is for example disclosed in WO97/05410, and a shift control apparatus thereof is shown in FIG.
8
. As apparent from
FIG. 8
, the shift control apparatus is comprised of a first (select) actuator for operating a clutch
3
disposed between an engine
1
and a speed change apparatus (transmission)
2
, a second (shift) actuator
5
for operating each of synchromesh mechanisms in the transmission
2
, a power unit
6
, a speed-change switch
7
and an electronic control unit (ECU)
8
.
The power unit
6
of hydraulic type or electrical type operates the first and second actuators
4
and
5
. The speed-change switch
7
is operated by a driver and outputs a speed-change signal corresponding to a target speed-change shift to the ECU
8
. The ECU
8
, based on the shift-change signal from the speed-change switch
7
and signals from various sensors, commands the power unit
6
to control operation of the first and second actuators
4
and
5
electronically.
Thus, the speed-change signal from the speed-change switch
7
operated (switched) by the driver is processed in the ECU
8
, based on which the power unit
6
supplies predetermined operating outputs are supplied from the power unit
6
to the first and second actuators
4
and
5
, thereby performing a gear shift so-called “finger touch control”.
A synchromesh mechanism
9
of the above transmission shown in
FIG. 9
is provided with a sleeve
13
and a pair of synchronize rings
16
(briefly called “ring” hereinafter). The sleeve
13
is mounted, in a gear train including plural gears mounted on an input shaft (speed shaft)
10
, a counter shaft
11
and an output shaft
12
disposed parallel to each other, on the counter shaft
11
to be slidable axially and not rotatable relative to the counter shaft
11
. Each of the rings
16
frictionally contacts with a cone surface of a gear piece
15
(a clutch gear associated with free-rotate gears
14
L and
14
H to be rotated integral therewith) so that the sleeve
13
meshes with the gear piece
15
after eliminating a relative rotation difference therebetween.
When a shift of the transmission
2
having the synchromesh mechanism
9
is changed (up-shifted), the ring
16
pushed by the sleeve
13
driven by the second actuator
5
, is accelerated by the gear piece
15
of the free-rotate gear
14
H which rotates in higher speed than that of the sleeve
13
. Accordingly, as shown in
FIG. 10
, outer tooth
161
of the ring
16
abuts onto a rear surface (lower surface in
FIG. 10
)
13
r
of the sleeve
13
facing rearwardly, relative to a rotate direction A (upward in
FIG. 10
) of the counter shaft
11
(this is called “balk point”). In a push-apart process after the balk point, the sleeve
13
is as shown by a two-dotted line pushed by an operate force F of the second actuator
5
, to push the ring
16
by a drive force F
1
leftwardly (in FIG.
10
), and to push apart the ring
16
by a push-apart force F′ downwardly (in FIG.
10
). Thus, outer tooth
141
of the gear piece
15
of free-rotate gear
14
H rotating in higher rotation speed is pushed apart, so that the sleeve
13
engaged with the gear piece
15
of the free-rotate gear
14
H.
On the other hand, when a shift of the transmission
2
having the synchromesh mechanism
9
is down-shifted, the ring
16
pushed by the sleeve
13
driven by the second actuator
5
, is decelerated by the gear piece
15
of the free-rotate gear
14
L which rotates in lower speed than that of the sleeve
13
. Accordingly, as shown in
FIG. 11
, outer tooth
161
of the ring
16
abuts onto a front surface (upper surface in
FIG. 11
)
13
r
of the sleeve
13
facing frontwardly, relative to a rotate direction A (upward in
FIG. 10
) of the counter shaft
11
(this is called balk point). In a push-apart process after the balk point, the sleeve
13
is as shown by a two-dotted line pushed by an operate force F of the second actuator
5
, to push the ring
16
by a drive force F
1
rightwardly (in FIG.
11
), and to push apart the ring
16
by a push-apart force F′ upwardly (in FIG.
11
). Thus, outer tooth
141
of the gear piece
15
of free-rotate gear
14
L rotating in lower rotation speed is pushed apart, so that the sleeve
13
engaged with the gear piece
15
of the free-rotate gear
14
L.
The push-apart force F′ of the ring
16
by the sleeve
13
in shifting-up and shifting-down operations is generally determined by value of a tip angle &thgr; of the chamfer
132
of the sleeve
13
and a value of drive force F of the sleeve
13
. Provided that the value of drive force F of the sleeve
13
by the second actuator
5
is constant, the push-apart force F′ becomes larger as the value of the tip angle &thgr; of the chamfer
132
becomes smaller. However, since the push-apart force F′ needs to be smaller than the cone torque to perform the synchronize operation, the tip angle &thgr; can not be selected to be smaller over a predetermined value. For this reason, in designing each components, the tip angle &thgr; of the sleeve
13
is determined in advance, then the second actuator
5
which can generate the drive force F sufficient to obtain the force F′ necessary for push-aparting the ring
16
is selected.
However, in the conventional automatic transmission, there is actually a case where the second actuator
5
which has ability or power twice compared with that required from design aspect is needed. This results from the fact that, when the automatic transmission is installed on the vehicle, the push-apart force F′ based on the drive force F applied from the second actuator
5
and necessary for the sleeve
13
varies, depending on a resistance of a lubricant oil (briefly called “oil” hereinafter) contained in a transmission case based on a dynamic viscosity thereof. In detail, in the synchromesh mechanism
9
of the transmission
2
shown in
FIG. 9
, the dynamic viscosity of oil a surface level of which normally corresponds to position of the counter shaft
11
increases in a low-temperature condition, so that an agitate or stir resistance of the oil also increases. The gear pieces
15
associated with the free-rotate gears
14
H and
14
L and the rings
16
, in rotating in the oil receive the stir resistances F″ in a direction reverse to the rotate direction A of the counter shaft
11
, as shown in
FIGS. 10 and 11
.
This stir resistance F″ acts onto the ring
16
, especially in the down-shift as shown in
FIG. 11
, in the direction reverse to the push-apart force F′ applied to the ring
16
and the gear piece
15
by the sleeve
13
. In order to make the push-apart force F′ larger than the stir resistance F″ (F′>F″), the larger drive force F should be applied to the sleeve
13
from the second actuator
5
, which needs to make the power of the second actuator
5
larger. The stir resistance F″ of the oil increases like an index function as the atmospheric temperature i.e. the oil temperature decreases, and the stir resistance F″ in the normal temperature may become twice or more when the oil is used in the cold area.
Accordingly, in the conventional automatic transmission, the second actuator
5
shifting the sleeve
13
needs to have the drive force F which can overcome the stir resistance F″ of the oil due to the dynamic viscosity thereof in the low temperature. As the result, when the second actuator
5
is of hydraulic type operated by an oil pressure or air pressure, diameter of a piston or capacity of an accumulator of pump will becomes
Aisin Ai Co., Ltd.
Burns Doane , Swecker, Mathis LLP
Ho Ha
Marmor Charles A
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