192 clutches and power-stop control – Clutches – Progressive engagement
Reexamination Certificate
1999-11-02
2001-06-12
Marmor, Charles A. (Department: 3681)
192 clutches and power-stop control
Clutches
Progressive engagement
C074S339000, C192S053320
Reexamination Certificate
active
06244404
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a synchronizer for manual transmission and a method thereof, and more particularly to a simplified synchronizer for a manual transmission with an improved changing-speed feeling in forward and reverse changing-speed operations.
2. Description of Prior Art
In general, a manual transmission of an automobile changes power generated from an engine into proper driving force and outputs it in accordance with changes in driving states of the automobile, which provides an optimum driving capability.
As shown in
FIGS. 7 and 8
, the manual transmission comprises a plurality of levels of driving gears (first, second, third, fourth, fifth and backward)
50
assembled and idled at input shaft I, a synchronizer
51
disposed among the driving gears
50
for rotating along with the input shaft I to transmit/block power to the driving gears
50
in response to operation by shifting levers (not shown) and a plurality of driven gears
52
fixed at the output axis and meshed with the driving gears
50
.
In order to manipulate the synchronizer
51
with the shifting levers, a plurality of shifting rails (R) are assembled with a plurality of shifting forks (P) fixed thereon. In order to transmit power conveyed by the differential gear (D) of an output axis (O) to wheels at both sides, a differential unit (DF) is coupled therewith.
The synchronizer
51
is constructed to synchronize the rotational speed of the input shaft I and the driving gears
50
with a braking torque by steps to smoothly change speeds. In order to simplify the structure of the synchronizer, a separate reverse synchronizer is not prepared. Instead, only a device is used for simply stopping the input shaft I and then for accomplishing the reverse changing speed.
As shown in
FIG. 9
, the aforementioned synchronizer is constructed with a clutch hub
54
coupled with the input shaft I for rotation and a plurality of key slots
53
formed at the periphery thereof, an synchro-key
56
inserted at the key slots
53
with its internal surface being supported by a synchronizing spring
55
to be loaded for extending outside, a clutch sleeve
58
coupled at the outer surface of the clutch hub
54
with a sleeve gear
57
assembled at the lower side thereof for enabling to slide toward the input shaft and to rotate with the synchro-key
56
being closely attached to the internal surface thereof, a synchronizer ring
61
positioned at the lateral surface of the clutch sleeve
58
with a first frictional surface
59
of a cone shape formed at the internal peripheral surface thereof for accomplishing synchronization by being pushed by the synchro-key
56
and a synchro-gear
60
for coupling the sleeve gear
57
, and shifting gears
63
extensively formed at the driving gears
50
with a second frictional surface
62
to rub with the first frictional surface
59
by steps.
Particularly, a predetermined size of a protruder
64
and a groove
65
are formed at the position where the synchro-key
56
and the clutch sleeve
58
contact with each other for pushing the synchronizer ring
61
if less than a predetermined level of force is applied, or for letting the clutch sleeve
58
climb over the synchro-key
56
if more than a predetermined level of force is applied.
In addition, in order to perform the reverse changing-speed operations, there are provided a brake ring
68
disposed at one side of the clutch sleeve
58
for being pushed by the shynchro-key
56
and has a third frictional surface
66
formed at its internal peripheral surface and a brake gear
67
for meshing with the sleeve gear
57
, a ring-shaped reverse cone part
70
fixedly on mounted a transmission case C and formed with a fourth frictional surface
69
for being rubbed with the third frictional surface
66
by steps when the brake ring
68
is pushed.
A wave spring
71
is assembled between the transmission case and the brake ring
68
for pushing the brake ring
68
to be apart from the reverse cone part
70
after completion of the reverse changing-speed operation.
At this time, when the clutch sleeve
58
is moved to a direction R, a reverse changing-speed lever
72
and a reverse shifting gear
73
shown in
FIG. 8
move to mesh with a reverse gear tooth
74
formed at the first/second clutch sleeve
58
′, referred to as symbol RG in
FIG. 7
, and a reverse driving gear
75
fixed at the input shaft I. Then, the reverse changing-speed operation is completed.
Now, the operations of the synchronizer will be described. If the shifting lever is manipulated, for instance, to carry out the shifting operation to the fifth level, the clutch sleeve
58
is moved to the right in the drawing.
If the clutch sleeve
58
is moved to the right, the synchro-key
56
tightly attached to the internal peripheral surface of the clutch hub
54
at a predetermined level of force moves to push the synchronizer ring
61
. At this time, the first and second frictional surfaces
59
,
62
are rubbed to start synchronizing the rotational speed of the clutch sleeve
58
and the driving gear
50
.
If the rotational speed of the clutch sleeve
58
and the driving gear
50
gets synchronized, the clutch sleeve
58
climbs over the protruder
64
of the synchro-key
56
to be meshed with the shychro-gear
60
of the synchronizer ring
61
and then passes through it to be meshed with the shifting gear
63
of the driving gear
50
. When the clutch sleeve
58
and the shifting gear
63
of the driving gears
50
are meshed, a changing-speed operation is completed.
At this time, procedures of the reverse changing-speed operation will be described. If the shifting lever is put to the reverse driving position, the clutch sleeve
58
moves to the direction R as indicated in the drawing (to the left in the drawing).
If the clutch sleeve
58
moves to the direction R, the synchro-key
56
pushes the brake ring
68
to get rubbed the third and fourth frictional surfaces
66
,
69
respectively formed at the brake ring
68
and at the reverse cone part
70
, thereby reducing the rotational speed of the clutch sleeve
58
, that is, the input shaft I.
If the rotational speed of the clutch sleeve
58
reduces, the clutch sleeve
58
meshes with the brake gear
67
of the brake ring
68
to press down the wave spring
71
.
At this time, while the reverse changing-speed lever
72
shown in
FIG. 8
moves along with the clutch sleeve
58
, the reverse gear
73
interlocked at the reverse changing-speed lever
72
moves to be meshed between the reverse gear tooth
74
of the first/second clutch sleeve
58
′ and the reverse driving gear
75
as shown in FIG.
10
.
If the reverse changing-speed operation is completed as described above, the force that pushes the brake ring
68
is exhausted to get the brake ring
68
apart from the reverse cone part
70
due to elasticity of the wave spring
71
, thereby being able to reversely drive.
The synchronizer of the manual transmission described above comprises, in order to synchronize the driving gear and the clutch sleeve, the shynchro-key which slides to the axis from the clutch hub, the clutch sleeve which moves the synchro-key at a predetermined level of force to synchronize the synchronizer ring and the driving gear and is meshed with the shifting gear of the driving gear at more than a predetermined level of force, and the synchronizer spring which supports the synchro-key. However, there is a problem in the conventional synchronizer in that the structure thereof is complicated and the assembling capability of the synchro-key and others are poor, thereby increasing manufacturing cost and lowering assembling efficiency.
In addition, in order for the clutch sleeve to push the synchronizer ring at a predetermined level of force to be meshed with the shifting gear of the driving gear, the protruder and groove should be provided between the shynchro-key and the clutch sleeve. Therefore, there is another problem in the conventional synchronizer in that, when the clutch slee
Birch & Stewart Kolasch & Birch, LLP
Hyundai Motor Company
Marmor Charles A.
Rodriguez Saul
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