Note: Descriptions are shown in the official language in which they were submitted.
8 CA 02383121 2001-11-21
R s~csn~~ T~rtsrsissioN
The invention concerns a power branching transmission, especially for
tractors, wheeled and tracked working machines and commercial
vehicles. This includes vehicles and machines of all types, especially
wheeled vehicles and tracked vehicles of all types, self-propelled
working machines and construction machines, as well as trucks, mobile
cranes and the like.
The problem to be solved by the invention is to provide an
advantageous power branching transmission.
According to the invention, this problem is solved through the
characteristics of Claim 1. The power branching transmission has a
mechanical branch (mechanical drive, mechanical branch transmission)
and one or more planetary drives. The transmission input shaft of the
power branching transmission divides the power, for example, the
engine power of the tractor, the working machine, the other vehicle
or other machine, into a mechanical branch and a hydrostatic branch.
The mechanical power portion and the hydrostatic power portion are
then recombined by the planetary drive and output. Instead of a
planetary drive, another gear can be used that makes it possible to
recombine the mechanical power portion and the hydrostatic power
portion.
Advantageous further developments are described in the subsidiary
claims.
The mechanical branch includes preferably multiple clutches. It is
advantageous if multiple disk clutches are used. The clutches or
multiple disk clutches are preferably movable hydraulically. They are
preferably disengaged with spring power.
-1-
CA 02383121 2001-11-21
Preferably, the mechanical branch includes multiple shafts. It is
advantageous if the mechanical branch includes three shafts which are
preferably arranged in a triangle.
A further advantageous development is characterized in that multiple
or all shafts of the mechanical branch are provided with two clutches.
In this connection, it is advantageous when the first clutches in each
case and the second clutches in each case lie in one plane.
If the mechanical branch includes three shafts, preferably arranged
in a triangle, which are provided with two clutches, preferably
multiple disk clutches, it is advantageous if three clutches in each
case lie in a single plane. The first three clutches lie, therefore,
in a plane, and the three second clutches also lie in a single plane.
The arrangement in which the first and second clutches in each case
lie in a plane each is, however, advantageous with more or fewer than
three shafts.
According to a further advantageous development, the mechanical branch
comprises three shafts, preferably arranged in a triangle, where two
shafts with two clutches each, preferably multiple disk clutches, are
provided. In this regard, it is advantageous if two clutches in each
case lie in a plane. The first two clutches therefore lie in one
plane, and the second two clutches also lie in one plane.
Preferably, a clutch in each case can be engaged in a single plane.
As a result of the fact that a coupling is engaged or disengaged in
a plane, a large number of gear ratios can be obtained in an
advantageous manner.
A further advantageous development is characterized in that the ratio
of the mechanical part is designed in such a fashion that, at a
maximum 40~ hydraulic power share of a stage, the next higher stage
begins with 100$ mechanical power. As a result, the hydraulic power
-2-
CA 02383121 2001-11-21
can be kept low and in a good degree of effectiveness . In certain
applications, it may be sufficient for at least one or several ratios
of the mechanical part to be arranged in the manner described.
The hydrostatic portion preferably comprises a pump and a motor
(hydraulic motor) . In this regard, what is preferable is an adjustable
pump and/or an adjustable motor. Pump and motor are placed in the
closed hydraulic circuit.
According to a further advantageous development, multiple planetary
drives are provided. To each planetary drive, a motor (hydraulic
motor), preferably an adjustable motor, is assigned. This is
especially advantageous if the power branching transmission serves to
drive a wheeled or tracked working machine. In this case, on each side
of the tracked vehicles that supplies power or on each driven wheel
of the wheel-driven working machine, a planetary drive can be provided
to supply power. The sun gear of each planetary drive is separately
driven in this case by a motor or a hydraulic motor or an adjusting
motor. In this manner, the vehicle can be steered through the
hydrostatic power portions the wheel, which receives a greater portion
of the hydrostatic power, rotates faster, so that the vehicle performs
corresponding curved travel.
It is possible that a single pump, which is preferably an adjusting
pump, supplies several or all motors. Preferably, the hydrostatic
part, however, has multiple pumps, preferably multiple adjusting
pumps. It is advantageous if each motor, and therefore each planetary
drive, is assigned a pump. In this case, each individual motor can be
fed from its own pump. This brings the advantage that losses due to
pressure differences can be avoided.
A further advantageous development is characterized in that the
rotational direction of the sun gear of the planetary drives, after
the start-up stage up to the highest gear, preferably up to 6th gear,
-3-
CA 02383121 2001-11-21
remains the same. The start-up stage can be 2nd gear, but can also be
3rd or 4th gear. This is especially advantageous if the gear shifting
is or becomes automated.
The invention further concerns a tractor or a wheel-driven or track-
driven working machine or a commercial truck (a commercial vehicle),
which is characterized by a power branching transmission, in
accordance with the invention.
Sample embodiments of the invention are explained in detail using the
attached drawing. In the drawing, the following are shown:
Fig. 1 a power branching transmission in schematic view and
Fig. 2 a modified embodiment of the power branching
transmission.
The power branching transmission shown in Fig. 1 consists of a
mechanical branch 1, a hydrostatic branch 2 and a planetary drive 3.
The input 4 of the power branching transmission is connected, through
a universal joint 5, to the transmission input shaft 6, which splits
the input power into a mechanical branch and a hydrostatic branch. The
mechanical portion of the power and the hydrostatic portion of the
power are then recombined by the planetary drive 3 (instead of the
planetary drive, a differential drive could also be used). The
planetary drive 3 has a sun gear 7, a planet gear shaft 8 with planet
gears and a ring gear 9. Through the planet gear shaft 8, the total
of the power of the mechanical branch and the hydrostatic branch is
transmitted to the axle distributor gear. This is done through a gear
11 connected to the planet gear shaft 8, which works together with a
gear 12 seated on the transmission output shaft 10. The transmission
output shaft 10 is connected to the axles through universal joints 13,
14, 15, 16.
CA 02383121 2001-11-21
The mechanical branch 1 or the mechanical drive consists of three
shafts 17, 18; 19, 20 and 21, 22, each with two clutches 2, C; R, B
and 1, A. In each case, three clutches lie in one plane. The first
three clutches 2, R and 1, which are connected to the input shafts 17,
19 and 21, lie in one plane, namely plane 1. Similarly, the three
clutches C, B and A, which are connected to the output shafts 18, 20
and 22, are in one plane, namely plane 2. As shown in the figure in
the drawing, the input and output shafts with two clutches each are
aligned with each other, namely the input and output shafts 17 and 18
of the clutches 2 and C, the input and output shafts 19 and 20 of the
clutches R and B and the input and output shafts 21 and 22 of the
clutches 1 and A.
All clutches are multiple disk clutches. Furthermore, all clutches can
be actuated under load.
The transmission input shaft 6 is connected to gears 23, 24, 25. The
gear 23 works together with the gear 26, which is seated on the input
shaft 21. The gear 24 works together with the gear 27, which is seated
on input shaft 19. The gear 25 works together with the gear 28, which
is seated on input shaft 17.
Gear 29 is seated on output shaft 18. Gears 30 and 31, as well as the
ring gear 9 of the planetary drive, are seated on output shaft 20.
Gear 32 is seated on output shaft 22.
A clutch housing with a clutch gear 33 belongs to clutches 2 and C.
A clutch housing with a clutch gear 34 belongs to clutches R and B.
A clutch housing with a clutch gear 35 belongs to clutches 1 and A.
The clutch gears 33, 34 and 35 mesh with each other.
The three shafts 17, 18 and 19, 20 and 21, 22 are arranged in a
triangle. In operation, one clutch of each level is engaged in order
to obtain power flow through to the ring gear 9 of the planetary
-5-
CA 02383121 2001-11-21
drive. Therefore, there is always engaged one clutch of 2, R or 1 in
plane 1, as well as one of the clutches C, B or A of plane 2. The
clutches, which are multiple disk clutches, are engaged hydraulically
and disengaged with spring power.
As shown in the figure in the drawing, the planetary drive is seated
on that shaft with which a change in the direction of rotation can be
achieved with three different RPM, namely shaft 20. The three
rotational speeds with inverted direction of rotation can be used to
drive backwards.
The hydrostatic branch 2 or the hydrostatic drive consists of an
adjusting pump 36, which can be driven by the transmission input shaft
6, and an adjusting motor (hydraulic motor) 37, which work together
in a closed hydraulic circuit 38. The shaft 39 of the sun gear 7 of
the planetary drive can be driven by the adjusting motor.
Through the power branching transmission, the ring gear 9 of the
planetary drive can be driven mechanically at six rotational speeds
in one direction of rotation, and at three rotational speeds in the
other direction of rotation. The sun gear 7 of the planetary drive can
be driven hydrostatically with continuously variable speed in both
directions. A special advantage of the power branching transmission
lies in the fact that the power can be transmitted hydrostatically or
completely mechanically.
When driving completely hydrostatically, the ring gear 9 of the
planetary drive is blocked by engaging two or possibly three clutches
on level 2. The power is then transmitted only through the hydraulic
branch 2 and the sun gear 7.
If the sun gear 7 of the planetary drive is hydraulically blocked,
then a 6/3 step load shifting transmission is obtained.
.6_
CA 02383121 2001-11-21
The mechanical power transmission in branch 1 is set in such a manner
that with a maximum 40~ hydraulic power portion of one stage, the next
higher stage begins with 100 mechanical power. As a result, the
hydraulic power can be kept low and at a favorable degree of
efficiency.
After the start-up stage, the rotational direction of the sun gear 7
of the planetary drive remains constant up to the 6th gear, which is
advantageous if the gear shifting is automated or becomes automated.
Figure 2 shows a modified embodiment of a power branching transmission
in which those components that agreed with the embodiment of Figure
1 are provided with the same reference symbols, so that they need not
be described again. In this embodiment, the power branching
transmission consists of a mechanical branch 1, a hydrostatic branch
2 and two planetary drives 41, 42, to each of which an adjusting motor
(hydraulic motor) 43 and 44 is assigned. The mechanical branch 1
consists of three shafts 17, 18; 19, 29 and 21, 22 arranged in a
triangle, where, however, only on shafts 17, 18 and 21, 22, two
clutches 2, B and 1, A are provided in each case. In each case, there
are two clutches in a plane and, indeed, clutches 2 and 1, which are
connected to the input shafts 17 and 21 (plane 1) and clutches B and
A, which are connected to the output shafts 18 and 22 (plane 2). As
in the embodiment according to Figure 1, the input and output shafts
of each two clutches are aligned with each other, namely the input and
output shafts 17 and 18 of the clutches 2 and B and the input and
output shafts 21 and 22 of the clutches 1 and A.
The transmission input shaft 6 is connected to gears 23 and 25. The
gear 23 works together with the gear 26, which is seated on the input
shaft 21. Gear 25 works together with gear 28, which is seated on
input shaft 17. Gear 29 is seated on the output shaft 18. Seated on
the output shaft 20 are gears 30 and 31, as well as the gear (tapered
gear) 45 of an axle distribution drive 46, which meshes with a further
gear (tapered gear) 47 of the axle distribution drive 46, which is
CA 02383121 2001-11-21
seated on a shaft 48. The rotating axles of the gears (tapered gears)
45 and 47 run at right angles to each other.
Gear 32 is seated on the output shaft 22.
A clutch housing with a clutch gear 33 belongs clutches 2 and B. A
clutch housing with a clutch gear 35 belongs clutches 1 and A. The
clutch gear 33 meshes with a gear 34, which in turn meshes with gear
35.
The shafts 17, 18 and 19, 20 and 21, 22 are arranged in a triangle.
In operation, one clutch in each plane is engaged, thus one of the
clutches 2 and 1 in level 1 and one of the clutches B and A in level
2.
The hydrostatic branch 2 consists of two adjusting pumps 49, 50, which
can be driven by the transmission input shaft 6 and of the two
adjusting motors (hydraulic motors) 43 and 44, where the first
adjusting pump 49 works together with the first adjusting motor 43 in
a closed hydraulic circuit 51, and where the second adjusting pump 50
works together with the second adjusting motor 44 in a second closed
hydraulic circuit 52.
The shaft 53 of the sun gear of the first planetary drive 41 can be
driven by the first adjusting motor 43. The shaft 54 of the sun gear
of the second planetary drive 42 can be driven by the second adjusting
motor 44.
At the ends of the shaft 48, gears 55, 56 are provided, each of which
meshes with teeth that are provided on the ring gears of planetary
drives 41 and 42.
The planet gear shaft 57 of the first planetary drive 41 is connected
to a first wheel 58 of a wheel-driven working machine. The planet gear
_g_
CA 02383121 2001-11-21
shaft 59 of the second planetary drive 42 is connected to a second
wheel 60 of the wheel-driven working machine. The wheel-driven working
machine can be steered by a difference in the adjustment of the
adjusting motors 43 and 44.
In the embodiment shown in Figure 1, the power recombination takes
place at the output of the mechanical branch and before the axle
distribution gearbox. For vehicles or working machines with
individually driven wheels and for tracked vehicles with individually
driven sides, the embodiment shown in Figure 2 is offered, in which
the mechanical branch is brought to the wheels 58, 60 or tracks and
in which the power recombination takes place at the end of the drive
chain. As can be seen from Figure 2, on each driving side of the
tracked vehicle or on each driving wheel, there is a planetary drive
41, 42 to recombine the power. The sun gear of this planetary drive
is driven separately by a hydraulic motor 43, 44. As a result, the
hydrostatic portion of the power can be used to steer the vehicle. In
this connection, a single pump can supply all hydraulic motors or, in
order to avoid losses due to pressure differences, each individual
motor 43, 44 may be provided with its own pump 49, 50, as represented
in Figure 2.
For special applications, when, for example, the main portion of the
work is directed in one direction, the number of the mechanical stages
can be reduced and placed in the main working direction in order to
obtain a high mechanical power portion and a low hydrostatic power
portion. Reversing can be done completely hydrostatically by blocking
the ring gear. In this case, it is possible to drive completely
hydrostatically in both directions of travel.
The embodiment shown in Figure 1 is primarily suitable for tractors,
the embodiment according to Figure 2 is primarily suitable for wheel
and track-driven working machines.
-9-
