Machine element or mechanism – Gearing – Interchangeably locked
Reexamination Certificate
2001-04-02
2002-12-17
Estremsky, Sherry (Department: 3681)
Machine element or mechanism
Gearing
Interchangeably locked
C074S329000
Reexamination Certificate
active
06494110
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a four parallel shaft type automatic transmission comprising, in parallel, a main shaft, a counter shaft, a first sub-shaft and a second sub-shaft.
2. The Related Art
Japanese Patent Publication No. 2900201 discloses a three parallel shaft type automatic transmission for a vehicle which can establish five forward speed gear stages and one reverse gear stage.
FIG. 6
is a schematic diagram illustrating the above-mentioned three parallel shaft type automatic transmission of the art; this automatic transmission T comprises a main shaft Sm connected to an engine E via a torque converter
23
, a counter shaft Sc and a secondary shaft Ss placed parallel to the main shaft Sm, and the rotation of the counter shaft Sc is transmitted to right and left driven wheels WR and WL via a differential gear box
25
.
A first gear G
1
and a second gear G
2
are supported in a relatively rotatable manner on the main shaft Sm which is supported by means of a pair of bearings
14
and
15
, and the first gear G
1
and the second gear G
2
are connected to the main shaft Sm via a fourth speed-reverse clutch C
4
R and a fifth clutch C
5
respectively. The fourth speed-reverse clutch C
4
R and the fifth speed clutch C
5
are provided back-to-back on an axially central part of the main shaft Sm. A ninth gear G
9
for transmitting the forward driving force to the counter shaft Sc and the secondary shaft Ss is fixed on the main shaft Sm.
A third gear G
3
and a fourth gear G
4
are supported in a relatively rotatable manner on the secondary shaft Ss which is supported by means of a pair of bearings
18
and
19
, and the third gear G
3
and the fourth gear G
4
are connected to the secondary shaft Ss via a first speed clutch C
1
and a second speed clutch C
2
respectively. The first speed clutch C
1
and the second speed clutch C
2
are provided back-to-back on an axially central part of the secondary shaft Ss. A tenth gear G
10
is fixed on the secondary shaft Ss, and the forward driving force is transmitted from the main shaft Sm to the tenth gear G
10
.
A sixth gear G
6
meshed with the second gear G
2
of the main shaft Sm is fixed on the counter shaft Sc which is supported by means of a pair of bearings
16
and
17
, and a seventh gear G
7
and an eighth gear G
8
meshed with the third gear G
3
and the fourth gear G
4
of the secondary shaft Ss respectively are also fixed on the counter shaft Sc. Furthermore, a fifth gear G
5
meshed with the first gear G
1
of the main shaft Sm is supported on the counter shaft Sc in a relatively rotatable manner, and the fifth gear G
5
is connected to the counter shaft Sc via a chamfer
56
. Moreover, an eleventh gear G
11
meshed with both the ninth gear G
9
of the main shaft Sm and the tenth gear G
10
of the secondary shaft Ss is supported on the counter shaft Sc in a relatively rotatable manner, and the eleventh gear G
11
is connected to the counter shaft Sc by means of a third speed clutch C
3
. The third speed clutch C
3
is provided on the end of the counter shaft Sc opposite to the engine E.
A main reverse gear
51
formed integrally with the first gear G
1
of the main shaft Sm is meshed with a counter reverse gear
54
supported on the counter shaft Sc via a reverse idler gear
55
in a relatively rotatable manner, and this counter reverse gear
54
is connected to the counter shaft Sc by means of the above-mentioned chamfer
56
.
In accordance with the above-mentioned arrangement, when the first speed clutch C
1
is engaged, the rotation of the main shaft Sm is transmitted to the counter shaft Sc via the ninth gear G
9
, the eleventh gear G
11
, the tenth gear G
10
, the secondary shaft Ss, the first speed clutch C
1
, the third gear G
3
and the seventh gear G
7
so establishing a first speed gear shift stage.
When the second speed clutch C
2
is engaged, the rotation of the main shaft Sm is transmitted to the counter shaft Sc via the ninth gear G
9
, the eleventh gear G
11
, the tenth gear G
10
, the secondary shaft Ss, the second speed clutch C
2
, the fourth gear G
4
and the eighth gear G
8
so establishing a second speed gear shift stage.
When the third speed clutch C
3
is engaged, the rotation of the main shaft Sm is transmitted to the counter shaft Sc via the ninth gear G
9
, the eleventh gear G
11
and the third speed clutch C
3
so establishing a third speed gear shift stage.
When the fourth speed-reverse clutch C
4
R is engaged, the rotation of the main shaft Sm is transmitted to the counter shaft Sc via the fourth speed-reverse clutch C
4
R, the first gear G
1
, the fifth gear G
5
and the chamfer
56
so establishing a fourth speed gear shift stage.
When the fifth speed clutch C
5
is engaged, the rotation of the main shaft Sm is transmitted to the counter shaft Sc via the fifth speed clutch C
5
, the second gear G
2
and the sixth gear G
6
so establishing a fifth speed gear shift stage.
When the counter reverse gear
54
is connected to the counter shaft Sc by means of the chamfer
56
in a state in which the fourth speed-reverse clutch C
4
R is engaged, the rotation of the main shaft Sm is transmitted as a reverse rotation to the counter shaft Sc via the fourth speed-reverse clutch C
4
R, the main reverse gear
51
, the reverse idler gear
55
, the counter reverse gear
54
and the chamfer
56
so establishing a reverse gear shift stage.
However, with regard to the conventional stepless transmission illustrated in
FIG. 6
, the third speed clutch C
3
provided on the counter shaft Sc is placed on the end of the shaft opposite to the engine E, this third speed clutch C
3
is not aligned with any of the other clutches in a direction perpendicular to the axial direction, and there is therefore the problem that the axial length of the automatic transmission increases by an amount corresponding to the distance the third speed clutch C
3
projects in the axial direction.
SUMMARY OF THE INVENTION
The present invention has been carried out in view of the above-mentioned circumstances and it is an object of the present invention to reduce the axial length of the automatic transmission by efficiently arranging the gears and clutches used for establishing a plurality of gear shift stages.
In order to achieve the above-mentioned objective, in accordance with a first characteristic of the invention, there is proposed a four parallel shaft type automatic transmission comprising, in parallel, a main shaft, a counter shaft to which the rotation of the main shaft is directly transmitted via a first route, a first sub-shaft provided on a second route through which the rotation of the main shaft is transmitted to the counter shaft, and a second sub-shaft provided on a third route through which the rotation of the main shaft is transmitted to the counter shaft, wherein a first gear for transmitting the rotation of the main shaft to the counter shaft via the second route and a second gear for transmitting the rotation of the main shaft to the counter shaft via the first route are provided on the main shaft, a third gear and a fourth gear for transmitting the rotation of the main shaft to the counter shaft via the third route are provided on the second sub-shaft, the first gear and the third gear are provided within a first plane extending in a direction perpendicular to the shafts, and the second gear and the fourth gear are provided within a second plane extending in a direction perpendicular to the shafts.
In accordance with the above-mentioned arrangement, the first gear provided on the main shaft for transmitting the rotation of the main shaft to the counter shaft via the second route and the third gear provided on the second sub-shaft for transmitting the rotation of the main shaft to the counter shaft via the third route are provided within a first plane extending in a direction perpendicular to the shafts, and the second gear provided on the main shaft for transmitting the rotation of the main shaft to the counter shaft via the first route and the fourth gea
Armstrong Westerman & Hattori, LLP
Estremsky Sherry
Honda Giken Kogyo Kabushiki Kaisha
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