Planetary change-speed transmission for automotive vehicles

A change-speed transmission for motor vehicles, with the transmission including a planetary gear transmission arrangement having a pair of sun gears, a pair of ring gears, and a double webbed planetary gear carrier supporting at least one primary planetary gear and at least one secondary planetary gear. The primary planetary gear meshes with one of the sun gears and the secondary planetary gear meshes with the primary planetary gear and the other of the sun gears. One sun gear, acting as a free transmisson member and one ring gear are respectively adapted to be brought into an operative connection by a gear shift brake arrangement. The other sun gear as well as a further transmission member may be placed in a driving connection with the input shaft of the transmission. Both ring gears mesh with the primary planetary gear and one of the ring gears as well as the transmission member acting on the output shaft may be brought into driving connection respectively with one transmission member of a planetary gear coupling transmission. An additional transmission member of the planetary gear coupling transmission is adapted to be connected to the output shaft of the transmission.

The present invention relates to a transmission and, more particularly, to 
an automatic planetary gear change-speed transmission for motor vehicles 
which includes a double-webbed planetary gear transmission having each two 
sun gears and ring gears and with a fifth transmission member formed by a 
double-webbed planetary gear carrier with a primary or main planet gear 
and a secondary or auxiliary planet gear, and in which the main or primary 
planet gear meshing with the secondary or auxiliary planet gear 
furthermore meshes with one sun gear as well as with one ring gear and the 
other sun gear meshes with the secondary planet gear, in which one sun 
gear is acting as a free transmission member and one ring gear can be 
brought into an operative connection with a gear shift brake and the other 
sun gear as well as a further transmission member can be drivingly 
connected with an input shaft driveable by a driving engine and the 
remaining transmission member acts on an output shaft adapted to be 
coupled with wheels of the motor vehicle. 
In a change-speed trasmission of the aforementioned type (U.S. Pat. No. 
2,901,923), the carrier is connected to the output shaft while the on ring 
gear, which is larger in diameter, cooperates with the primary or main 
planet gear by way of a further auxiliary planet gear. Although this prior 
art change-speed transmission provides for five forward speeds and one 
reverse speed, with the fifth speed or gear being designed as an overspeed 
gear, the largest speed reduction ratio obtainable for the lowest gear is 
only about 2:1. An increase of the reduction ratio for the lowest speed or 
gear to about 3:1 to 4:1 would lead in this prior art transmission to a 
further enlargement of the large ring gear; however, such enlargement is 
undesirable. Finally, it is unavoidable in this prior art change-speed 
transmission that during the speed. changes between the reduced forward 
speeds, a group change of the participating gear shift control members 
occurs. 
The aim underlying the present invention essentially resides in providing a 
change-speed transmission of the aforementioned type with a fifth speed or 
gear functioning as an overdrive which enables the realization of a larger 
speed reduction ratio for the lowest speed while avoiding group change as 
well as a necessary enlargement of the size of the ring gears. 
The underlying problems are solved in accordance with the present invention 
in that both ring gears mesh with the primary or main planet gear and in 
that one ring gear as also the transmission member acting on the output 
shaft are adapted to be brought into driving connection with one 
transmission member each of a planetary gear coupling transmission while a 
third transmission member of the coupling transmission is adapted to be 
connected to the output shaft. 
With the change-speed transmission in accordance with the present 
invention, the driving clutch for one sun gear of a primary or main planet 
gear is able to provide the drive for all reduced forward speeds so that 
no group change occurs. 
Moreover, with the change-speed transmission of the present invention, both 
ring gears of the primary or main planet gear are of equal size so that 
the transmission is more compact and simpler in its manufacture. 
Additionally, with the change-speed transmission of the present invention, 
the coupling transmission provides an additional speed reduction for the 
lowest gear whereby the total transmission ratio is increased. 
In accordance with further advantageous features of the present invention, 
the driving clutch for the one sun gear of the double-webbed transmission 
needs to be controlled only in a coasting operation of the reduced forward 
gears. For this purpose, a one way roller clutch is connected into the 
driving connection between the input shaft and the one sun gear of the 
double-webbed transmission. In the change-speed transmission of the 
present invention, the construction of the coupling transmission may be of 
any desired, known type. For example, the coupling transmission may 
consist of a simple one-webbed planetary gear transmission, of a 
double-webbed planetary gear transmission, or of several connected 
planetary gear sets. 
In accordance with the present invention, the ring gear of the primary or 
main planet gear disposed opposite to the input shaft may be drivingly 
connected with a transmission member of the coupling transmission and the 
carrier of the primary or main planet gear may be drivingly connected with 
the input shaft. 
Additionally, in accordance with the present invention, a planetary gear 
carrier of the coupling transmission may be connected with the output 
shaft and a central gear may be brought into driving connection with the 
ring gear of the primary or main planet gear facing the input shaft. 
With a change-speed transmission having a hydrodynamic torque converter or 
flow unit, in which the impeller is connected to the input shaft and a 
driving clutch is inserted in a driving connection between a further 
impeller of the hydrodynamic flow unit and the one sun gear of the 
double-webbed transmission and a further driving clutch is inserted in a 
driving connection between the input shaft and the further transmission 
member of the double-webbed transmission, according to a further feature 
of the present invention, the two impellers are operable to be fixed in 
position relative to each other directly by a bridging clutch and the two 
driving clutches may be operatively connected between the secondary clutch 
half of the bridging clutch and the associated transmission member. 
In accordance with further features of the present invention, the 
double-webbed carrier may be connected to a driving web disposed axially 
between the two sun gears of the double-webbed transmission, and the 
driving clutch, not associated with the one sun gear, acts on a hollow 
shaft extending through the sun gear facing the input shaft and is 
connected to the driving web. 
The two driving clutches, in accordance with the present invention, are 
arranged with respect to their position between the hydrodynamic flow unit 
or torque converter and the double-webbed transmission while the secondary 
clutch half of the driving clutch lying between the hydrodynamic flow unit 
and the other driving clutch may be connected, by way of an intermediate 
shaft extending through the hollow shaft connected to the driving web, 
with the sun gear of the double-webbed transmission disposed opposite to 
the input shaft. 
In accordance with another feature of the present invention, a driving drum 
may be connected to the two lateral driving webs between which a central 
driving web is disposed; one lateral driving web may be connected with an 
intermediate shaft connected with the secondary clutch half of the 
bridging clutch and the other lateral driving web may be connected to a 
hollow shaft, while the central driving web is connected with the 
intermediate shaft extending through this hollow shaft and connected with 
the sun gear; the driving drum includes a primary clutch half and the 
central driving web the secondary clutch half of the driving clutch of the 
sun gear. 
In accordance with still further features of the present invention, a one 
way roller or free-wheeling clutch is arranged within the driving drum in 
such a manner that one clutch ring or race is connected to the central 
driving web and the other clutch ring or race is connected to the 
intermediate shaft connected to the secondary clutch half of the bridging 
clutch. 
In accordance with the present invention, the two ring gears of the primary 
planetary gear have preferably the same number of teeth. 
Accordingly, it is an object of the present invention to provide a 
planetary gear change-speed transmission for motor vehicles which avoids, 
by simple means, the aforementioned shortcomings and disadvantages 
encountered in the prior art. 
Another object of the present invention resides in providing a planetary 
change-speed transmission for motor vehicles which enables the attainment 
of a large speed reduction ratio for the lowest speed. 
A further object of the present invention resides in providing a planetary 
change-speed transmission for motor vehicles which avoids a group changing 
during shifting of reduced forward speeds. 
Yet another object of the present invention resides in providing a 
change-speed transmission which is simple in construction and therefore 
relatively inexpensive to manufacture. 
A further object of the present invention resides in providing a planetary 
gear change-speed transmission for motor vehicles which enables an 
increase in the total transmission ratio.

Referring now to the drawings wherein like reference numerals are used 
throughout the various views to designate like parts and, more 
particularly to FIG. 1, according to this Figure, an input shaft 21 
adapted to be driven by a driving engine (not shown) of a motor vehicle 
(not shown) is connected by way of a drive connection generally designated 
by the reference numeral 27 to a sun gear 15 and by way of a drive 
connection generally designated by the reference numeral 28 to a carrier 
18 of a double-webbed planetary gear transmission generally designated by 
the reference numeral 30. The driving connection 27 includes a 
hydrodynamic torque converter generally designated by the reference 
numeral 31, a driving clutch generally designated by the reference 
character K.sub.3 connected after the torque converter, and a one-way free 
wheeling clutch generally designated by the reference character F.sub.1 
connected in parallel with the driving clutch K.sub.3. 
The gear carrier 18 carries at least one primary or main planet gear 19 and 
at least one secondary or auxiliary planet gear 20 meshing with the 
primary or main planet gear 19. The secondary or auxiliary planet gear 20 
meshes with a sun gear 15. The primary or main planet gear 19 furthermore 
meshes with a further sun gear 14 as well as with two ring gears 16 and 
17. The further sun gear 14 and the ring gear 16 which are free 
transmission members, are adapted to be fixedly braked by a gear shift 
brake generally designated by reference character B.sub.1 and B.sub.3 
respectively. The ring gear 17 is connected to a ring gear 23 of a 
coupling transmission generally designated by reference numeral 25, whose 
a planetary gear carrier 26 carrying at least one planet gear 26' is 
connected with an output shaft 22 adapted to be coupled, in a conventional 
manner, with wheels (not shown) of the motor vehicle. 
The coupling transmission 25 also includes a sun gear 24 adapted to be 
connected to the carrier 18 by way of a driving connection generally 
designated by the reference numeral 29. The driving connection 29 
includes, in a parallel arrangement, a one way or free wheeling clutch 
generally designated by reference character F and a gear shift clutch 
generally designated by reference character K.sub.2. The sun gear 24 is 
additionally adapted to be braked by the gear shift brake B.sub.2. 
A housing 32, driven by the input shaft 21, is connected to the impeller 65 
of the hydrodynamic torque converter generally designated by reference 
numeral 31 whose turbine 34 is connected by way of an intermediate shaft 
82, with the one way or free wheeling clutch F.sub.1 and the driving 
clutch K.sub.3. The driving connection 28 includes an intermediate shaft 
83 which is connected to the carrier 18. The intermediate shaft 83 is 
adapted to be connected with the input shaft 21 by way of the driving 
clutch generally designated by the reference character K.sub.4. The 
one-way or free-wheeling clutches F and F.sub.1 prevent in each case a 
backward rotation of the hub with respect to the shaft. 
A shown in FIG. 3, in first gear, the gear shift brake B.sub.2 and the 
driving clutch K.sub.3 is engaged. Consequently, the sun gear 15 are being 
driven while the carrier 18 is fixedly braked indirectly by way of the one 
way clutch F and the sun gear 24 is fixedly braked directly by the gear 
shift brake B.sub.2. In this manner, the highest speed reduction is 
engaged in the transmission 30 with the carrier 18 fixed or stationary, 
which together with the reduction of the coupling transmission 25, 
produces an overall transmission ratio for the lowest gear of about 4:1. 
In the second gear, the brake B.sub.1 is additionally engaged and thus the 
sun gear 14 is held fast. As a result thereof, the carrier 18 is driven in 
the driving direction of rotation by the primary or main planet gear 19 
rolling off along the sun gear 14 so that the overall transmission ratio 
in the second gear is lower than in the first gear. 
In third gear, the brake B.sub.1 is disengaged and the driving clutch 
K.sub.4 is engaged. As a result thereof, the transmission 30 is shifted 
into a transmission ratio 1:1 by the driving clutch K.sub.3 remaining 
engaged so that only the speed reduction of the coupling transmission 25 
is effective. 
In fourth gear, the brake B.sub.2 is disengaged and the gear shift clutch 
K.sub.2 is engaged. As a result thereof, both transmission 30 and 25 are 
shifted into a direct or 1:1 transmission ratio so that the output shaft 
22 has the same rotational speed as the input shaft 21. 
In fifth gear, the gear shift brake B.sub.1, the gear shift clutch K.sub.2, 
and the driving clutch K.sub.4 are engaged. As a result thereof, the 
carrier 18 is driven by the input shaft 21 so that the ring gears 17 and 
23 are driven at an overdrive speed by way of the primary or main planet 
gear 19 rolling off on the fixedly braked sun gear 14. The coupling 
transmission 25 is shifted into direct by the gear shift clutch K.sub.2 so 
that the output shaft 22 has the fast rotational speed of the ring gears 
17 and 23. 
In reverse gear, the gear shift brake B.sub.3 is and the driving clutch 
K.sub.3 are engaged. The sun gear 15, in driving connection with the input 
shaft 21, drives the carrier 18 by way of the primary or main planet gear 
19 rolling off on the fixedly braked ring gear 16 in the opposite driving 
direction of rotation, which thus overtakes the ring gears 17 and 23 
operating as a reaction member for the coupling transmission 25. The 
carrier 18 is coupled through the one way clutch F with the sun gear 24 
which drives the carrier 26 in the opposite direction of rotation. In this 
reverse gear operation, a reduction still occurs in the coupling 
transmission 25 due to the relative rotation between the carrier 18 and 
the ring gear 23. 
The change-speed transmission of FIG. 2 essentially conforms to the 
transmission of FIG. 1; however, in the transmission of FIG. 2, the 
position of the two sun gears 14, 15 in the transmission 30 is reversed 
with respect to each other and the driving connection 27 leads to the sun 
gear 14 meshing directly with the primary or main planet gear 19. The sun 
gear 15 meshing with the secondary or auxiliary planet gear 20 is then 
adapted to be fixedly braked by way of the gear shift brake B.sub.1. 
Moreover, the driving connection 28 leads to the rear ring gear 17 and the 
driving connection 29 leads to the front ring gear 16. In all other 
features, the transmissions of FIGS. 1 and 2 coincide. 
The shifting diagram of FIG. 3 also applied to the change speed 
transmission of FIG. 2. Accordingly, the gear shift brake B.sub.2 and the 
driving clutch K.sub.3 are engaged in the first gear. In this manner, the 
sun gear 24 is directly braked and the ring gear 16 is braked by way of 
the driving connection 29 and the one way clutch F, while the sun gear 14 
is driven by the input shaft 21 by way of the intermediate shaft 82. The 
carrier 18 is driven in a forward direction of rotation by the primary or 
main planet gear 19 rolling off on the fixedly braked ring gear 16 with a 
reduced speed, whereby the ring gear 23 drives the carrier 26 and 
therewith the output shaft 22 with a further reduction toward lower speed. 
With the change-speed transmission of FIG. 2 in second gear, the gear shift 
brake B.sub.1 is additionally engaged, whereby also the ring gear 16, 
stationary in the first gear, rotates as a reaction member in the driving 
direction of rotation. As a result thereof, the carrier 18 continues to be 
speed reduced but is driven faster than in first gear so that, in second 
gear, a smaller overall speed reduction ratio results than in first gear. 
In third gear, the driving clutches K.sub.3 and K.sub.4 as well as the gear 
shift brake B.sub.2 are engaged. As a result thereof, the transmission 30 
is shifted into direct so that the ring gear 23 of the coupling 
transmission 25 is driven from the input shaft 21 and the speed reduction 
results solely from the reduction of the coupling transmission 25. 
To shift the change-speed transmission of FIG. 2 into fourth gear the gear 
shift brake B.sub.2 is disengaged and the gear shift clutch K.sub.2 is 
engaged. As a result thereof, the coupling transmission 25 is shifted into 
direct gear so that the input shaft 21 and output shaft 22 have the same 
speed. 
In fifth gear, the gear shift brake B.sub.1, the gear shift clutch K.sub.2 
and the driving clutch K.sub.4 are engaged. In this manner, the sun gear 
15 is fixedly braked, the ring gear 17 is driven by the input shaft 21, 
and the ring gear 16 is connected with the sun gear 24. A transmission 
ratio providing an increased speed occurs between the primary or main 
planet gear 19 and the secondary or auxiliary planet geaar 20 at the 
carrier cooperating as a reaction member with the ring gear 23 so that the 
ring gear 16 leads with respect to the ring gear 17 and, thus, with 
respect to the input shaft 21, i.e., rotates faster than the ring gear 17 
and the input shaft 21. As a result thereof, the sun gear 24 drives the 
output shaft 22 at an increased or higher speed in the driving direction 
of rotation. 
In reverse gear, the gear shift brake B.sub.3, the driving clutch K.sub.3, 
and the gear shift clutch K.sub.2 are engaged. As a result thereof, the 
carrier 18 and the ring gear 23 are held fast and the sun gear 14 is 
driven by the input shaft 21. The sun gear 14 drives, by way of the 
primary or main planet gear 19, the ring gear 16 in the opposite direction 
of rotation, whereby the sun gear 24, connected to the ring gear 16 by way 
of the gear shift clutch K.sub.2, drives the carrier 26 and therewith the 
output shaft 22 in the opposite driving direction of rotation. 
The change-speed transmission of FIG. 4 differs in function and operation 
from FIG. 1 merely in that the driving clutch K'.sub.4 for the carrier 18 
does not act directly on the input shaft 21 but instead by way of a 
bridging clutch generally designated by the reference numeral 66. 
Additionally, the driving clutch K.sub.4 ' is not disposed in the housing 
32 of the torque converter 31 but rather is located, with respect to the 
input shaft 21, to the rear of the hydrodynamic torque converter 31 and in 
front of the driving clutch K.sub.3 '. The arrangement of the change-speed 
transmission of FIG. 4 has the advantage that the hydrodynamic torque 
converter 31 can be bridged in all gears. With respect to all other 
features, the embodiments of FIGS. 1 and 4 conform with each other so that 
reference may be had, in this context, to the description of FIG. 1 and 
its operation. 
With regard to the bridging clutch 66, as shown in FIG. 4, the clutch 66 is 
operatively connected between, on the one hand, the turbine 34 and the 
input shaft 21 and, on the other hand, the impeller 65. A secondary clutch 
half 67 of the bridging clutch 66 is connected to an intermediate shaft 77 
which cooperates with the driving clutches K.sub.3 ' and K.sub.4 '. 
The embodiment of FIG. 5 differs from that of FIG. 4 only in that the 
driving clutch K.sub.3 " is positionally arranged or located between the 
torque converter 31 and the driving clutch K.sub.4 ". This arrangement or 
location of the driving clutch K.sub.3 " is achieved in that the driving 
clutch K.sub.4 " rotates on a hollow shaft 69 which is connected to a 
driving web 68 of the carrier 18 disposed axially between the two sun 
gears 14 and 15. An intermediate shaft 72 which extends through the hollow 
shaft 69, connects the sun gear 15 with a central drive web 76 which is 
disposed between two lateral driving webs 74 and 75. The lateral driving 
webs 74 and 75 are connected to a driving drum 73 which includes the 
clutch half 78 of the driving clutch K.sub.3 ". The secondary clutch half 
71 of the driving clutch K.sub.3 " is connected to the driving web 76. 
While the one driving web 74 is connected to the intermediate shaft 77, 
the other driving web 75 leads to the driving clutch K.sub.4 " by way of a 
hollow shaft 107. In all other respects the change-speed transmission of 
FIG. 5 corresponds to the transmission of FIG. 4. 
The embodiment of FIG. 6 represents a constructional realization of the 
arrangement of the driving clutch K.sub.3 " in the change-speed 
transmission of FIG. 5. More particularly, a driving drum 73, constructed 
on its inside as an outer lamellae carrier 78 of the driving clutch 
K.sub.3 ", is connected with two lateral driving webs 74 and 75; a central 
driving web 76 which is disposed between the lateral driving webs 74 and 
75, is provided with the inner lamellae carrier 71. The driving web 74 is 
connected to the intermediate shaft 77 by way of a coupling sleeve 80. The 
coupling sleeve 80 forms the inner race of the one-way or free-wheeling 
clutch F.sub.1 whose outer race 79 is fixed at the driving web 76. The 
central driving web 76 is connected to an intermediate shaft 72 leading to 
the sun gear 15. The intermediate shaft 72 extends through a hollow shaft 
107 leading to the driving clutch K.sub.4 ". The other lateral driving web 
75 is connected to the hollow shaft 107. 
The particular advantage of the change-speed transmission of FIG. 6 resides 
in the fact that the driving clutch K.sub.3 " may be accommodated by an 
intermediate housing 108 which can be flanged to the front end wall 109 of 
a four-speed change-speed transmission. 
While we have shown and described several embodiments in accordance with 
the present invention, it is understood that the same is not limited 
thereto but is susceptible of numerous changes and modifications as known 
to one having ordinary skill in the art and we therefore do not wish to be 
limited to the details shown and described herein, but intend to cover all 
such modifications as are encompassed by the scope of the appended claims.