U.S. patent application number 09/844279 was filed with the patent office on 2002-04-11 for synchronous meshing type automatic transmission control system.
Invention is credited to Miyamoto, Syoichi.
Application Number | 20020040612 09/844279 |
Document ID | / |
Family ID | 18789899 |
Filed Date | 2002-04-11 |
United States Patent
Application |
20020040612 |
Kind Code |
A1 |
Miyamoto, Syoichi |
April 11, 2002 |
Synchronous meshing type automatic transmission control system
Abstract
A synchronous meshing type automatic transmission control system
is provided to be capable of shortening a time for gear change
without generation of noises from gears and degradation of a
synchronizing mechanism in durability, and comprises an internal
combustion engine mounted on a vehicle, a speed change mechanism
coupled to the internal combustion engine through a clutch, a
shift-select actuator for selectively coupling one set of a
plurality of sets of speed change gears having different gear
ratios and intervening between an input shaft coupled to the clutch
of the speed change mechanism and an output shaft for driving the
vehicle, and a control device for inputting thereinto an output
signal of a shift-select position sensor, which detects a selected
position of the shift-select actuator, to operate a position of the
shift-select actuator for gear change and for putting the clutch in
weak coupling in a state, in which no gear is coupled between the
input shaft and the output shaft in the course of gear change.
Inventors: |
Miyamoto, Syoichi; (Tokyo,
JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN,
MACPEAK & SEAS, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
WASHINGTON
DC
20037-3213
US
|
Family ID: |
18789899 |
Appl. No.: |
09/844279 |
Filed: |
April 30, 2001 |
Current U.S.
Class: |
74/336R ;
477/80 |
Current CPC
Class: |
B60W 10/10 20130101;
F16D 48/064 20130101; B60W 10/06 20130101; B60W 2510/0638 20130101;
B60W 30/19 20130101; Y10T 74/1926 20150115; B60W 10/11 20130101;
F16D 2500/30806 20130101; F16D 2500/3067 20130101; F16D 2500/3144
20130101; F16H 61/2807 20130101; F16D 2500/70462 20130101; B60W
2540/10 20130101; F16D 2500/5104 20130101; F16D 48/068 20130101;
F16D 2500/31466 20130101; F16D 2500/70488 20130101; F16D 2500/30415
20130101; F16D 2500/5045 20130101; B60W 2540/16 20130101; F16H
2061/2823 20130101; F16H 2059/6807 20130101; B60W 10/02
20130101 |
Class at
Publication: |
74/336.00R ;
477/80 |
International
Class: |
B60K 041/22 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2000 |
JP |
P 2000-309823 |
Claims
What is claimed is:
1. A synchronous meshing type automatic transmission control system
comprising, a speed change mechanism coupled to an internal
combustion engine on a vehicle through a clutch, a shift-select
actuator for selectively coupling one set of a plurality of sets of
speed change gears having different gear ratios and intervening
between an input shaft of the speed change mechanism coupled to the
clutch and an output shaft of the speed change mechanism for
driving the vehicle, a shift-select position sensor for detecting a
selected position of the shift-select actuator, and a control means
for inputting thereinto an output signal of the shift-select
position sensor to operate a position of the shift-select actuator
for gear change and for putting the clutch in weak coupling in the
case where the internal combustion engine is smaller in rotational
speed than the input shaft of the speed change mechanism in a
state, in which no gear is coupled between the input shaft and the
output shaft in the course of gear change.
2. The synchronous meshing type automatic transmission control
system according to claim 1, wherein the coupling strength of the
clutch put in weak coupling is set in accordance with a kind of
shift in the speed change mechanism and the rotational speed of the
internal combustion engine.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to control of a synchronous meshing
type automatic transmission control system coupled to a crankshaft
of an internal combustion engine via a clutch, and more
particularly, to control for shortening a gear change time.
[0002] A method of controlling a synchronous meshing type automatic
transmission control system used in a vehicle is disclosed in, for
example, Japanese Patent Laid-Open No. 270252/1988. A technique
disclosed in this document comprises, in an arrangement, in which a
synchronous meshing type automatic transmission control system is
coupled to an internal combustion engine via an electromagnetic
clutch, controlling a throttle opening so that an amplitude of
change between the rotational speed of the internal combustion
engine at the time of release of the electromagnetic clutch and the
rotational speed of the internal combustion engine at the time of
coupling of the electromagnetic clutch when speed change gears are
to be switched is maintained within a predetermined range, and
correcting a relationship between the rotational speed of the
internal combustion engine and the throttle opening with the use of
a learning routine every speed change operation so that such
control can correspond to respective conditions and dispersion in
internal combustion engines, thereby mitigating a speed change
shock.
[0003] A shift device disclosed in the prior art for performing
gear change of a synchronous meshing type automatic transmission
control system employs a pair of three-position hydraulic cylinders
for actuating a shift-select lever in an axial direction and in a
direction of rotation, and is designed to drive a three-position
hydraulic cylinder for selection to select a shift rod and to drive
a three-position hydraulic cylinder for shift to move the selected
shift rod, thus performing speed change stages. Also, in addition
to such hydraulic type shift device, there is generally used an
electrically driven, synchronous meshing type automatic
transmission control system which uses two motors to perform shift
driving and select driving.
[0004] The switching action of gear stages in an electrically
driven, synchronous meshing type automatic transmission control
system comprises using a select actuator to select a coupling means
being operated while controlling a select position by means of a
positional signal of a select position sensor, and moving the
coupling means by means of a shift actuator to perform coupling of
a target gear while controlling a shift position by means of a
positional signal of a shift position sensor, controlling an amount
of driving of a shift-select actuator with a parameter being a
deviation amount between an actual shift-select position detected
by a shift-select position sensor and a target shift-select
position to conform the shift-select position to the target
position, and using an electromagnetic clutch to make transmission
of power between an internal combustion engine and the synchronous
meshing type automatic speed change mechanism ON/OFF in speed
change operation.
[0005] In a vehicle using such synchronous meshing type automatic
speed change mechanism and a clutch in transmission and shut-off of
power between a crankshaft of an internal combustion engine and an
input shaft of the synchronous meshing type automatic speed change
mechanism, moment of inertia becomes great since gears and a driven
member of the clutch are mounted on the input shaft of the
synchronous meshing type automatic speed change mechanism, whereby
it takes time in achieving rotational synchronization of the input
shaft of the synchronous meshing type automatic speed change
mechanism and an output shaft at the time of gear change, so that
there is caused a problem that such time for gear change gives a
driver an uncomfortable feeling to worsen a driving feeling. Also,
when an action of rotational synchronization is suddenly performed
in order to shorten a time of speed change for coping with such
problem, there is caused a problem that noises generate from gears
and a synchronizing mechanism for achieving rotational
synchronization is degraded in durability.
SUMMARY OF THE INVENTION
[0006] The invention has been contemplated to solve such problems,
and has its object to provide a synchronous meshing type automatic
transmission control system capable of shortening a time for gear
change without generation of noises from gears and degradation of a
synchronizing mechanism in durability.
[0007] A synchronous meshing type automatic transmission control
system according to the invention comprises a speed change
mechanism coupled to an internal combustion engine on a vehicle
through a clutch, a shift-select actuator for selectively coupling
one set of a plurality of sets of speed change gears having
different gear ratios and intervening between an input shaft of the
speed change mechanism coupled to the clutch and an output shaft of
the speed change mechanism for driving the vehicle, a shift-select
position sensor for detecting a selected position of the
shift-select actuator, and a control means for inputting thereinto
an output signal of the shift-select position sensor to operate a
position of the shift-select actuator for gear change and for
putting the clutch in weak coupling in the case where the internal
combustion engine is smaller in rotational speed than the input
shaft of the speed change mechanism in a state, in which no gear is
coupled between the input shaft and the output shaft in the course
of gear change.
[0008] Also, according to the invention the coupling strength of
the clutch put in weak coupling is set on the basis of rotational
speed of the internal combustion engine, whereby it is possible to
stably shorten a time for gear change irrespective of rotational
speeds of the internal combustion engine and of the input shaft in
the initial stage of speed change action.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a block diagram showing a constitution of a
synchronous meshing type automatic transmission control system
according to a first embodiment of the invention.
[0010] FIG. 2 is a view illustrating an operation of the
synchronous meshing type automatic transmission control system
according to the first embodiment of the invention.
[0011] FIG. 3 is a view illustrating an operation of the
synchronous meshing type automatic transmission control system
according to the first embodiment of the invention.
[0012] FIG. 4 is a flowchart illustrating an operation of the
synchronous meshing type automatic transmission control system
according to the first embodiment of the invention.
[0013] FIG. 5 is a flowchart illustrating an operation of the
synchronous meshing type automatic transmission control system
according to the first embodiment of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0014] First Embodiment
[0015] FIGS. 1 to 5 illustrate a constitution and an operation of a
synchronous meshing type automatic transmission control system
according to a first embodiment of the invention, FIG. 1 being a
block diagram showing the constitution of the synchronous meshing
type automatic transmission control system, FIGS. 2 and 3 being
views illustrating the operation, and FIGS. 4 and 5 being
flowcharts illustrating the operation. In FIG. 1, the reference
numeral 1 designates an internal combustion engine, 2 an
electromagnetic clutch provided on a crankshaft 1a to couple the
internal combustion engine 1 to a synchronous meshing type
automatic speed change mechanism 3, 4 a control unit serving as a
control means for controlling the synchronous meshing type
automatic speed change mechanism 3, 5 a shift-select actuator
controlled by the control unit 4 to operate gear coupling of the
synchronous meshing type automatic speed change mechanism 3 in a
manner described later, and 6 a shift-select position sensor for
detecting an operated position of the shift-select actuator 5.
[0016] The synchronous meshing type automatic speed change
mechanism 3 has an input shaft 3a and an output shaft 3b, the input
shaft 3a being coupled to a driven member (not shown) of the
electromagnetic clutch 2 and designed to be coupled to and
separated from a crankshaft 1a of the internal combustion engine 1
upon ON/OFF of the electromagnetic clutch 2, and the output shaft
3b being designed to drive a vehicle. A plurality of sets of speed
change gears (not shown) having different gear ratios are provided
between the input shaft 3a and the output shaft 3b, and a
shift-select actuator 5 operates a coupling mechanism (not shown)
to select and couple one set among the plurality of sets of speed
change gears to thereby couple the input shaft 3a and the output
shaft 3b with each other, and changes selection of speed change
gears to thereby effect a speed change operation.
[0017] The reference numeral 7 designates an accelerator position
sensor for outputting a signal conformed to an amount of stepping
of an accelerator pedal (not shown), and 8 a throttle actuator for
operating an opened degree of a throttle valve 10 provided in an
intake passage 9 of the internal combustion engine 1. A signal of
the accelerator position sensor 7 is processed in the control unit
4 to be delivered to the throttle actuator 8 to actuate the
throttle valve 10 to a target throttle opening conformed to an
amount of stepping of an accelerator pedal (not shown), and is
feed-back controlled by a throttle opening sensor (not shown).
Also, the throttle actuator 8 is also operated by a predetermined
program stored in the control unit 4 at the time of speed change
action. In addition, the reference numeral 11 designates a shift
lever for delivering a command of a driver's shift operation
position to the control unit 4, 12 an output shaft rotational speed
sensor for measuring the rotational speed of the output shaft 3b of
the synchronous meshing type automatic speed change mechanism 3,
and 13 an internal combustion engine rotational speed sensor for
measuring the rotational speed of the internal combustion engine
1.
[0018] The electromagnetic clutch 2 is controlled by the control
unit 4 to ON/OFF control coupling between the crankshaft 1a of the
internal combustion engine 1 and the input shaft 3a of the
synchronous meshing type automatic speed change mechanism 3, and is
given an exciting current in proportion to a transfer torque. Also,
the synchronous meshing type automatic speed change mechanism 3
comprises five sets of forward travel gears including, for example,
first to fifth gear speed gears of different gear ratios, and a set
of reverse travel gears, and while the shift-select position sensor
6 is detecting a shift position and a select position, the
shift-select actuator 5 operates a position of a coupling mechanism
(not shown) on the basis of a select target position and a shift
target position output from the control unit 4 to perform feed-back
control, thereby effecting a speed change operation.
[0019] The control unit 4 inputs thereinto a position signal from
the shift lever position 11 operated by a driver, an accelerator
pedal operating amount signal from the accelerator position sensor
7, a rotational speed signal from the output shaft rotational speed
sensor 12, a rotational speed signal from the internal combustion
engine rotational speed sensor 13 and so on to determine a number
of speed suited to a running state on the basis of a shift pattern
stored in the control unit 4 and to control the speed change
operation by operating the shift-select actuator 5 while detecting
a shift-select position by means of the shift-select position
sensor 6 as well as to control the electromagnetic clutch 2 at the
time of such speed change operation in a manner described
later.
[0020] Contents of control at the time of such speed change
operation with the control unit 4 are illustrated in FIGS. 2 and 3,
and an explanation will be exemplarily given to the case where the
speed change position of the synchronous meshing type automatic
speed change mechanism 3 shifts from the second gear speed position
to the third gear speed position. FIG. 2 shows a relationship
between a shift-select position and an output voltage of the
shift-select position sensor 6, and a value of the output voltage
of the shift-select position sensor 6 serves as a target position
of the shift-select actuator 5 operated by the control unit 4. An
axis of abscissa indicates a select position, and when gears for
the first gear speed and the second gear speed are selected, a
target voltage (target position) is VX1, when gears for the third
gear speed and the fourth gear speed are selected, a target voltage
(target position) is VX2, and when gears for the fifth gear speed
and the reverse travel are selected, a target voltage (target
position) is VX3.
[0021] Also, an axis of ordinate indicates a shift position, and
when gears for the second gear speed, the fourth gear speed and the
reverse travel are selected, a target voltage (target position) is
VY1, and when gears for the first gear speed, the third gear speed
and the fifth gear speed are selected, a target voltage (target
position) is VY7. Accordingly, when VX1 is selected for the select
position and VY1 is selected for the shift position, selection of a
gear for the second gear speed results. VY4 on the axis of ordinate
corresponds to a neutral position, and zones between VY2 and VY3
and between VY5 and VY6 indicate a position where a synchronizing
mechanism for synchronous rotation of the input shaft 3a and the
output shaft 3b in accordance with a gear ratio of a coupling
target gear acts while the coupling mechanism is moving in order to
couple with the respective gears. Accordingly, an actual neutral
zone where any one of the plurality of sets of speed change gears
between the input shaft 3a and the output shaft 3b is between VY3
and VY5.
[0022] In the case where the synchronous meshing type automatic
speed change mechanism 3 shifts the second gear speed to the third
gear speed, it is possible to divide control among three zones.
First, these include a A zone where the shift actuator changes a
shift position from the second gear speed position VY1 to the
neutral position VY4, a B zone where the select actuator changes a
select position from the first gear speed and second gear speed
position VX1 to the third gear speed and fourth gear speed position
VX2, and a C zone where the shift actuator changes a shift position
from the neutral position VY4 to the third gear speed VY7. In the
case where shift is effected from the second gear speed position to
the third gear speed position, it follows that the synchronizing
mechanism operates in the zone between VY5 and VY6. A state of such
shift change is shown in FIG. 3, in which time is represented on an
axis of abscissa.
[0023] In FIG. 3, when the control unit 4 begins a shift operation,
clutch current is made OFF at a time (p) before the beginning of
shift to release coupling of the crankshaft 1a and the input shaft
3a, so that a shift position moves from the VY1 position to the VY4
position in the A zone and subsequently a select position moves
from the VX1 position to the VX2 position in the B zone. Further, a
shift position moves from the VY4 position to the VY5 position in a
C1 zone of the C zone, and moves from the VY5 position to the VY6
position in a C2 zone. Further, a shift position moves from the VY6
position to the VY7 position in a C3 zone to complete a shift
operation, and the electromagnetic clutch 2 is excited at (q) point
to again couple the crankshaft 1a with the input shaft 3a. The
moving speed of a shift operation is set large in the A zone and in
the C1 zone, set small in the C2 zone so as to perform smooth
synchronization of the input shaft 3a and the output shaft 3b in
rotation since the synchronizing mechanism acts in the C2 zone and
set large again in the C3 zone after synchronization in rotation is
achieved.
[0024] While an exciting current is made OFF at a point of time (p)
before the beginning of shift in a manner described above, the
current-carrying operation of the electromagnetic clutch 2 is such
that while a shift position moves to VY5 past VY3, that is, in an
actual neutral zone where no one of the speed change gears effects
coupling, a minute current is passed to put the clutch in a weak
coupling state as shown in the drawings. While a current-carrying
point of time and a current-carrying duration for the weak coupling
can be optionally selected so long as the position from VY3 to VY5,
it is effective to set a current-carrying value depending upon the
rotational speed condition of the internal combustion engine 1.
[0025] FIG. 3 shows in its lowermost stage changes in rotational
speed of the internal combustion engine 1 and the input shaft 3a
until the electromagnetic clutch 2 couples again after it is shut
off. More specifically, when the electromagnetic clutch 2 is made
OFF at the point (p), the throttle valve 10 is closed and the
rotational speed of the internal combustion engine 1 decreases with
time as shown by a solid line L1 in the figure, but the input shaft
3a of the synchronous meshing type automatic speed change mechanism
3 is considerably small in rate of reduction in rotational speed as
shown by a chain line L2 in the figure because of its large moment
of inertia. However, a minute current is passed through the
electromagnetic clutch 2 to put the same in a weak coupling state
whereby the input shaft decreases in rotational speed together with
the internal combustion engine 1 as shown by the chain line L3 in
the figure and the synchronizing mechanism is actuated with release
of the weak coupling state of the electromagnetic clutch 2, so that
the input shaft 3a comes into synchronous rotation with the output
shaft 3b. Hereupon, a difference in rotational speed between the
input shaft 3a and the output shaft 3b decreases by an amount, by
which the input shaft 3a decreases in rotational speed due to the
weak coupling state of the electromagnetic clutch 2, so that it is
possible to shorten a time for synchronous rotation by the
synchronizing mechanism, that is, a time, during which the speed
change action is performed.
[0026] FIG. 4 is a flowchart illustrating an operating state of
control, in which a minute current is passed through the
electromagnetic clutch 2 to put the same in the weak coupling
state. Such operation comprises first judging in STEP 1 whether an
action of speed change is performed, and if such action is
performed, proceeding to STEP 2 to judge whether the action of
speed change is from the second gear speed to the third gear speed.
The reason why the action of speed change is limited to one from
the second gear speed to the third gear speed is that in the case
of other speed change, a shift-select position is different in
value of judgment and a similar routine is set every speed change.
Accordingly, when NO is judged in STEP 2, the processing will
transfer to other routine, which is different in only a value of
positional judgment set in another way.
[0027] When speed change is judged in STEP 2 to be from the second
gear speed to the third gear speed, the processing proceeds to STEP
3 to read a shift-select position to judge whether the position
permits a weak coupling state of the electromagnetic clutch 2. When
the position is judged to afford weak coupling of the
electromagnetic clutch 2, the processing proceeds to STEP 4 to
judge whether the internal combustion engine 1 is smaller in
rotational speed than the input shaft 3a of the synchronous meshing
type automatic speed change mechanism 3. When the input shaft 3a is
judged to be smaller in rotational speed than the internal
combustion engine, the processing proceeds to STEP 5 to set a
processing flag for weak coupling of the electromagnetic clutch 2.
In any of the cases where NO is judged in STEP 1, STEP 3 and STEP
5, the processing proceeds to STEP 6 to clear the processing flag
for weak coupling of the electromagnetic clutch 2.
[0028] Also, with a control routine shown in FIG. 5, it is judged
in STEP 11 whether a processing flag, shown in FIG. 4, for weak
coupling of the electromagnetic clutch 2 is in a set condition or
in a cleared condition. In the case of the cleared condition, the
processing is terminated, and in the set condition, the processing
proceeds to STEP 12 to judge whether speed change is in the course
of from the second gear speed to the third gear speed. When speed
change is in the course of from the second gear speed to the third
gear speed, the processing proceeds to STEP 13 to determine a value
of exciting current or the like depending upon kind of shift and
rotational speed of the internal combustion engine 1. When speed
change is judged in STEP 12 to be in other speed change stage
rather than in the course of from the second gear speed to the
third gear speed, a determined value such as the value of exciting
current is different, and so the processing proceeds to other
routine, which is different only in a set value set in another
way.
[0029] Such control routine is repeated every predetermined time to
read a target speed change stage and the rotational speed of the
internal combustion engine 1 upon judgment of being in the course
of speed change to put the electromagnetic clutch 2 in weak
coupling with a current of a condition meeting value in the case
where the input shaft 3a of the synchronous meshing type automatic
speed change mechanism 3 is larger in rotational speed than the
internal combustion engine 1, thus making the input shaft 3a of the
synchronous meshing type automatic speed change mechanism 3
consistent in rotational speed with the internal combustion engine
1. Accordingly, the input shaft 3a can be rapidly decreased in
rotational speed, and for this purpose it is effective to set an
exciting current of the electromagnetic clutch 2 conformed to
rotational speed of the internal combustion engine 1. In addition,
while the above-mentioned explanation has been given to the case
where the electromagnetic clutch 2 is used for coupling of the
internal combustion engine 1 and the synchronous meshing type
automatic speed change mechanism 3, such clutch is not limited to
an electromagnetic one since clutches, such as hydraulic control
clutch or the like, having the function capable of controlling the
strength at the time of coupling can perform control in a similar
manner.
* * * * *