Planetary gear transmission systems or components – Variable speed or direction transmission combined with...
Reexamination Certificate
2001-09-19
2003-10-28
Bonck, Rodney H. (Department: 3681)
Planetary gear transmission systems or components
Variable speed or direction transmission combined with...
C475S216000, C475S206000, C180S248000
Reexamination Certificate
active
06638194
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drive power transmission apparatus in a four-wheel-drive vehicle, in which a drive power distribution apparatus is assembled within a sub-axle type transmission apparatus.
2. Related Art
Language in the Japanese unexamined patent application publication 8-21503 describes a sub-shaft toroidal type stepless transmission, denoted by reference numeral
1001
in
FIG. 10
of the accompanying drawings.
The toroidal type stepless transmission
1001
is used in a dual-shaft drive vehicle, and has a torque converter
1003
, a forward/reverse switching mechanism
1005
, stepless transmission mechanisms
1007
and
1009
, and an output unit
1011
.
The drive power of a motor is transmitted from the torque converter
1003
to the forward/reverse switching mechanism
1005
. The forward/reverse switching mechanism
1005
is formed by a planetary gear and multivane clutch or the like, and performs switching in accordance with the rotational direction of the transmitted drive power, being either forward or reverse, which is then transmitted to the stepless transmission mechanisms
1007
and
1009
.
The stepless transmission mechanism
1007
has a pair of input disc
1013
and output disc
1015
, a friction roller
1017
, an input shaft
1019
, and an output shaft
1021
, and the stepless transmission mechanism
1009
has a pair of input disc
1023
and output disc
1025
, a friction roller
1027
, and also, in common with the stepless transmission mechanism
1007
, has the input shaft
1019
and the output shaft
1021
The input shaft
1019
is linked to the forward/reverse switching mechanism
1005
, and the output shaft
1021
is disposed at the outer periphery of the input shaft
1019
.
The input disc
1013
, the output disc
1015
, the input disc
1023
, and the output disc
1025
are each disposed so that the profiles of the frictional surfaces thereof form a circle and are in mutual opposition, the input discs
1013
and
1023
are fixed to the input shaft
1019
, and the output discs
1015
and
1025
are fixed to the output shaft
1021
.
The friction rollers
1017
and
1027
are pressed up against the frictional surfaces of the input disc
1013
and output disc
1015
, and the frictional surfaces of the input disc
1023
and the output disc
1025
, respectively, drive power transmitted from the forward/reverse switching mechanism
1005
to the input shaft
1019
being transmitted via the friction rollers
1017
and
1027
by frictional forces developed at their frictional surfaces to the output discs
1015
and
1025
and causing the output shaft
1021
to rotate.
When the above occurs, if the friction rollers
1017
and
1027
are rocked so as to change the angle of inclination, there is a change in the radius of contact with each disc, so that, for example, if an inclination is imparted in a direction so that the radius of contact of the friction rollers
1017
and
1027
with the input discs
1013
and
1023
is increased and the radius of contact with the output discs
1015
and
1025
decreases, then the speed of the output shaft
1021
increases, and if the imparted inclination is in the reverse direction, then the speed of the output shaft
1021
is reduced.
The output unit
1011
has gear sets
1029
and
1031
, a sub-shaft
1033
, an idler (not shown), an output shaft
1035
, and the like.
The gear set
1029
interconnects the output shaft
1021
and the sub-shaft
1033
. The gear set
1031
is formed by a gear
1037
on the sub-shaft
1033
, a gear
1039
on the output shaft
1035
, and the idler that interconnects the gears
1037
and
1039
, and serves for interconnection between the sub-shaft
1033
and the output shaft
1035
.
The output shaft
1035
is disposed coaxially with respect to the torque converter
1003
, the forward/reverse switching mechanism, and the stepless transmission mechanisms
1007
and
1009
, and the sub-shaft
1033
is parallel to these elements.
Drive power output from the stepless transmission mechanisms
1007
and
1009
to the output shaft
1021
is sent to wheels from the gear set
1029
, via the sub-shaft
1033
, the gear set
1031
, and the output shaft
1035
.
As described above, the stepless toroidal transmission
1001
is used in a two-wheel-drive vehicle. For use in a four-wheel-drive vehicle, to reduce the size and weight of the vehicle and enable the achievement of a low-cost four-wheel-drive vehicle, a power distribution unit is combined with an existing transmission (as a speed change gear) for a two-wheel-drive vehicle.
In the case of the stepless toroidal transmission
1001
, however, in which the output unit of a sub-shaft type transmission is made up of a sub-shaft
1033
, a gear set
1031
, and an output shaft
1035
and the like, if an input of the power distribution unit is linked to the output shaft
1035
, both the axial length of the combined transmission and power distribution unit increases, and the combined weight increases.
With an increased axial length, it is necessary to make a change in the propeller shaft and casing (transmission case and power distribution unit case), thereby causing a great increase in cost.
Existing transmissions have idle gears and torque-adjusting gear sets and the like for the purpose of rotational direction adjustment. For example, there is a case in which a gear set corresponding to the gear set
1031
of the stepless toroidal transmission
1001
has gears
1037
and
1039
on the sub-shaft
1033
and the output shaft
1035
, and an idle gear linked thereto, and a case in which this idle gear and the gear
1039
on the output shaft
1035
serve as a gear set for torque adjustment.
If the power distribution unit is assembled together with a transmission having such an idle gear or torque adjustment gear, because the idle gear or torque adjustment gear gives restriction to the mounting (connection) of the power distribution unit, in addition to an overall increase in size of the combined transmission and power distribution unit, it becomes difficult to achieve a reduction in cost.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a lightweight, compact, and low-cost power transmission apparatus, by combining various sub-shaft type transmission apparatuses with a power distribution apparatus.
More specifically, a first aspect of the present invention provides a power transmission apparatus comprising a transmission apparatus for outputting drive power of a motor from an input shaft, via a transmission mechanism disposed coaxially therewith, to a sub-shaft disposed in parallel thereto; and a power distribution apparatus disposed in parallel to the sub-shaft, for transmitting rotation of an input end member linked to an end of the sub-shaft, via respective output shafts, to a front-wheel end and a rear-wheel end, wherein at least the sub-shaft and the input end member are disposed in an axially overlapping relationship.
It is noted that in the present invention The phrase “the sub-shaft and the input end member are disposed in an axially overlapping relationship” means that, when the sub-shaft and the input end member are radially projected, their projections have mutually overlapping parts.
The “motor” as used above will be understood herein as meaning an internal combustion engine, or a motor converting electrical energy to rotative power.
In this manner, in the present invention, by linking an input end member to a sub-shaft of a sub-shaft type transmission apparatus, an existing power transmission apparatus for two-wheel driven vehicle is available to implement a power transmission for four-wheel driven vehicle.
Because at least the input end member of the power distribution apparatus has an axially overlapping relationship with the sub-shaft type transmission apparatus, it is unnecessary to change the axial dimension of the sub-shaft, or extremely suppressed, in addition to that the power transmission apparatus (power distribution apparatus and transmission appa
Ishikawa Yasuhiko
Nagai Masayuki
Abedelnour Dennis
Bonck Rodney H.
Tochigi Fuji Sangyo Kabushiki Kaisha
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