DE102008008234A1 - Adjustment unit for a continuously variable hydrostatic branched transmission - Google Patents

Abstract

The invention relates to an adjusting unit (16) for a stepless hydrostatically branched transmission, which transmission comprises two hydrostats (H1, H2), which are arranged at a distance next to one another and each pivotable about a pivot axis (27 or 28). In particular, a compact construction is achieved in that the adjusting unit (16) comprises hydraulically actuatable adjusting means (VZ1, VZ1 '; VZ2) for pivoting the hydrostats (H1, H2) about their pivot axes (27, 28), that control valves (SV1, SV2 ) for controlling the hydraulically actuatable adjusting means (VZ1, VZ1 '; VZ2) and actuating means (30; 42, ..., 46) for actuating the control valves (SV1, SV2) and in that the control valves (SV1, SV2) and the Actuating means (30, 42, ..., 46) between the two Hydrostaten (H1, H2) are arranged.

Description

TECHNICAL AREA

The The present invention relates to the field of transmission technology. It relates to an adjusting unit for a stepless hydrostatic Branched transmission according to the preamble of the claim 1.

STATE OF THE ART

Power split transmission, in particular for use in agricultural or construction-related vehicles such. As tractors have long been known. In such power split transmissions, the power applied to an input shaft or drive shaft, usually emitted by an internal combustion engine power is split on a first mechanical power branch with fixed ratio and a second, infinitely variable in the transmission power branch and then reunited to an output shaft or output shaft to be available. The second power branch is usually designed as a hydrostatic branch, in which two hydrostatic axial piston machines (hydrostatics) of sloping axis or swashplate type, which are hydraulically connected to each other, optionally operate as a pump or a motor. The translation can be changed by the change in the pivot angle of the cylinder block or the swash plate. The division of the power to the two power branches and the merger of the branched services is usually carried out by means of a planetary gear. Power split transmission of the type described are in different embodiment in the DE-A1-27 57 300 , of the DE-C2-29 04 572 , of the DE-A1-29 50 619 , of the DE-A1-37 07 382 , of the DE-A1-37 26 080 , of the DE-A1-39 12 369 , of the DE-A1-39 12 386 , of the DE-A1-43 43 401 , of the DE-A1-43 43 402 , of the EP-B1-0 249 001 and the EP-A2-1 273 828 disclosed.

• – Das Getriebe sollte einen hohen Wirkungsgrad über den ganzen Geschwindigkeitsbereich aufweisen. Dies sollte insbesondere bei den hohen Fahrgeschwindigkeiten, die im Strassenverkehr über einen längeren Zeitraum gefahren werden, der Fall sein.
• – Das Getriebe sollte kompakt aufgebaut sein, um den Einbau in die unterschiedlichsten Fahrzeuge möglichst ohne konstruktive Einschränkungen zu ermöglichen.
• – Das Getriebe sollte die Übertragung von hohen Leistungen ermöglichen.
• – Das Getriebe sollte zur Begrenzung der Leistungsverluste und Erhöhung der Funktionssicherheit möglichst einfach aufgebaut sein.
• – Das Getriebe sollte eine vollumfängliche elektronische Steuerung im Zusammenhang mit dem Motormanagement ermöglichen und auch bei Ausfall bestimmter Steuerungselemente ausreichende Notfahrprogramme zur Verfügung stellen.

In order to successfully use a power split transmission in practice, it should generally have the following characteristics:

• - The transmission should have high efficiency over the entire speed range. This should be the case especially for the high driving speeds that are used in road traffic over a longer period of time.
• - The gear should be compact, to allow installation in a variety of vehicles as possible without constructive restrictions.
• - The transmission should allow the transmission of high power.
• - The gear should be as simple as possible to limit the power losses and increase the reliability.
• - The transmission should allow full electronic control in conjunction with the engine management and provide sufficient emergency driving programs even if certain controls fail.

In the aforementioned DE-A1-43 43 402 is already described as a SHL transmission (Infinitely variable hydrostatic power split transmission) power split transmission, which is characterized by two hydraulically coupled similar hydrostatic in Schrägachsenbauweise coupled via clutch pairs or changeover elements K1 / K2 or K3 / K4 in different ways with a planetary differential gear are. The well-known SHL transmission has been used and tested under the type designation SHL-Z in city buses. The two hydrostats used have a swivel range of only 0-25 °. For forward travel, there are 3 speed ranges or driving ranges: In the first driving range, the hydrostatic component of the transmitted power at the starting point is 100% and then linearly approaches zero speed. In the second driving range, it goes from zero to a maximum of about 27% and then back to zero. In the third driving range, it goes from zero to a maximum value of 13% at the highest forward speed.

Of the hydrostatic power transmission branch such Gearbox usually comprises two hydrostatic axial piston machines, which are hydraulically related and of which the one works as a pump and the other as a motor. Depending on Driving the two machines can do their roles exchange.

The hydrostatic axial piston machines represent an essential part of the hydrostatic power split transmission and significantly shape the characteristics of the transmission such. As the efficiency, the size, the complexity, the covered speed range, type and number of speed steps and the like. Examples of such hydrostatic axial piston machines are in the DE-A1-198 33 711 or the DE-A1-100 44 784 or the US-A1-2004 / 0173089 disclosed. The mode of operation and theory of hydrostatic axial piston machines as well as a power-split tractor system equipped with them are published in a publication of the TU Munich from the year 2000 by H. Bork et al., "Modeling, Simulation and Analysis of a Continuously Variable Power Tractor Drive" , described.

Essential for the function of such transmission is the adjustment or pivoting of the hydrostat in a wide angular range, to change the power transfer in the hydraulic branch or the function of the hydrostats between motor function and pump function switch. The adjustment mechanism should be compact in structure, safe in operation and operable with sufficient accuracy be. In addition, it is desirable that Adjustment mechanism easily accessible for maintenance to design.

PRESENTATION OF THE INVENTION

It The object of the invention is to provide an adjusting unit which meets these requirements.

The The object is solved by the totality of the features of claim 1. Essential for the invention is that within the Adjustment provided hydraulically actuated adjusting means, Control valves and actuating means for actuating the control valves are located directly between the two hydrostats are. As a result, in particular a compact construction is achieved.

A Embodiment of the invention is characterized in that the Pivot axes of the hydrostats are aligned parallel to each other, that the control valves have longitudinal axes along which for actuating the control valves in each case a valve slide is displaceable, that the control valves at a distance from each other arranged so that their longitudinal axes are parallel aligned with each other and perpendicular to the pivot axes of the hydrostat are, and that the actuating means include adjusting lever over which the control valves are operated, and which in a perpendicular to the pivot axes of the hydrostatic lying pivot plane are pivotable.

Especially the actuating means further comprise an adjusting roller, which is arranged between the control valves and rotatable about an axis of rotation is parallel to the longitudinal axes of the control valves is aligned, and which at its periphery guideways to control the pivotal movement of the lever, which with their one ends the guideways on the adjusting roller scan.

Prefers the adjusting levers are pivotally mounted on the valve spools and engage with the hydrostats with their other ends, thus, that upon pivoting of the hydrostats about their pivot axes the adjusting lever) in a predetermined manner in its pivoting plane be pivoted, with the coupling between the levers and the hydrostat preferably one each about the pivot axes includes rotatable crank mechanism.

The Adjusting roller is driven in particular by an electric motor. For manual rotation of the adjustment can be between a motor and Adjusting roller arranged emergency operation be provided with which it is possible, in case of failure of other systems one Maintain emergency operation of the associated vehicle.

A Another embodiment of the invention is characterized in that the hydraulically actuated adjusting means for each hydrostatic comprise at least one adjusting cylinder, which with an adjusting piston on a pivotable about the pivot axis Swing lever of the hydrostatic attacks.

Especially can be two in opposite for each hydrostat Directions working adjusting cylinder may be provided, which preferably attack on the same pivot lever.

A further embodiment of the invention is characterized in that that the control valves for controlling the hydraulically actuated Adjustment means and the actuating means for actuating the control valves housed in an upwardly open housing are, which is closable with a lid that the control valves and selected actuating means on the underside the cover are mounted, and that the control valves with the hydraulically actuated adjusting over a pressure distribution system integrated in the cover with individual hydraulic channels keep in touch.

The Hydrostatic work in particular either as a pump and as a motor work, each pivoting range is at least +/- 45 °.

SHORT EXPLANATION THE FIGURES

The Invention will be described below with reference to embodiments explained in more detail in connection with the drawing become. Show it

1 in a schematic representation of the basic structure of an exemplary continuously variable hydraulic power split transmission, which is suitable for implementing the invention;

2 a perspective view (viewed obliquely from below) of a transmission according to the in 1 illustrated principle, wherein only the lid is shown with the underlying transmission and the control arranged above;

3 a perspective view (seen from obliquely below) of the two hydrostat from 2 with the associated adjustment unit according to a preferred embodiment of the invention;

4 the arrangement 3 seen in perspective view obliquely from above;

5 the adjustment from 4 without lid and without two of the adjusting cylinder;

6 seen obliquely from below the lid of the adjustment 3 with the attached control valves, the adjusting roller and the adjusting levers; and

7 the adjustment unit of 3 respectively. 4 without lid seen from above, with one of the adjusting cylinder is omitted.

WAYS TO EXECUTE THE INVENTION

In 1 is shown in a schematic representation of the basic structure of a continuously variable hydraulic power split transmission, which is particularly suitable for implementing the invention. The gear 10 transfers the power of an internal combustion engine 11 who in 1 is symbolized by a seated on a crankshaft piston. The gear 10 is with an input shaft (drive shaft) W1 with the internal combustion engine 11 connected. It outputs the transmitted power via an output shaft (output shaft) W7. Through the transmission 10 If necessary, a PTO shaft W8 extends, which is a direct continuation of the input shaft W1.

The core of the transmission 10 form a stepped planet drive 12 with a large sun gear Z1 and a small sun gear Z1 ', the double planet wheels Z2, Z2', the ring gear Z3 and the planetary gear with a gear Z8 rotatably connected 13 , and two hydrostatic axial piston machines or hydrostats H1 and H2, whose output shafts W6 and W12 respectively via a pair of clutches K3, K4 and K1, K2 in different ways to the input shaft W1, the output shaft W7 and the stepped planetary drive 12 can be coupled. The hydrostats H1 and H2, which optionally operate as a pump and motor, are hydraulically connected to each other via high pressure lines, not shown. The first hydrostat H1 can be coupled with its output shaft W6 by means of the clutch K3 via a countershaft from the gearwheel Z5 and a gearwheel Z4 connected in a rotationally fixed manner to the ring gear Z3 with the ring gear Z3. However, it can also be coupled to the input shaft W1 by means of the clutch K4 via the gearwheel Z11, the intermediate gear Z12 and the gearwheel Z10 arranged in a rotationally fixed manner on the input shaft W1.

The second hydrostat H2 can with its output shaft W12 on the one hand by means of the clutch K1 via the hollow shaft W11 and the rotationally fixedly arranged gear Z9, which meshes with the gear Z8, with the planet web 13 and thus be coupled to the output shaft W7. On the other hand, it can by means of the clutch K2 via the gear pair Z7, Z6 and the hollow shaft W2 with the smaller sun gear Z1 'of the stepped planetary drive 12 be coupled.

The pending on the input shaft W1 power is in the transmission 10 through the stepped planetary drive 12 divided into two power branches, namely a mechanical power branch and a hydraulic power branch and later recombined on the output shaft W7. The mechanical power branch runs from the input shaft W1 via the larger sun gear Z1, the double planet gears Z2, which are connected in a rotationally fixed manner to the input shaft W1, the planet web 13 and gear Z8. The hydraulic power branch runs over the two hydraulically connected hydrostats H1 and H2 and is designed differently depending on the circuit of the clutches K1, ..., K4. Like in the 1 is indicated in the drawing, the two hydrostat H1 and H2 can be pivoted by +/- 45 °.

One according to the transmission scheme 1 realized power split transmission is in 2 as viewed obliquely from below, showing only the lid with the transmission arranged underneath and the control arranged above it. The associated lower housing part can be configured differently depending on the requirement.

The gear 10 of the 2 comprises as a supporting part a substantially rectangular lid 14 , of a lying in a plane, provided with holes for the screw connection to the housing lower part, circumferential flange 15 is bounded. On the bottom of the lid 14 are in the actual gear core 17 in three mutually parallel, an isosceles triangle forming axes in 1 schematically shown transmission components (hydrostats, clutches, gears and shafts) arranged and stored. In one axis there is the first hydrostat H1 with the shafts W3, W5 and W6, the gears Z5 and Z11, and the clutches K3 and K4. In the second axis, there is the second hydrostat H2 with the shafts W9, W11 and W12, the gears Z7 and Z9, and the clutches K1 and K2. The third, middle axis includes W2, W7 and W10, the stepped planetary gear 12 , and the gears Z4, Z6, Z8 and Z10.

For storage and mounting of the gear core 17 on the bottom of the lid 14 are as essential components one parallel to the lid 14 oriented storage floor 22 , two vertically from the lid 14 downgoing, lateral support posts 20 . 21 , and two also vertically from the lid 14 downward outgoing, bearing walls provided, of which only the one bearing wall 23 you can see. The storage floor 22 limits the gear core 17 on the bottom. He is with the support posts 20 . 21 and the bearing walls 23 screwed. In the warehouse floor 22 are the lower pivot bearings 18 . 19 for each about a vertical axis (pivot axes 27 . 28 in 3 ) Swiveling housing of the hydrostatic units H1 and H2 arranged. The upper pivot bearings are not visible in the lid 14 housed himself. The mutually parallel, perpendicular to the three axes of the gear core 17 standing storage walls 23 serve to support the shafts belonging to the axles.

In particular, in the front storage wall 23 the coming of the clutches K1 / K2 and K3 / K4 shafts W9 and W3 stored. The associated bearings are each as a structural unit with a control hydraulics 24 respectively. 25 executed, which is in communication with the control on the top of the lid and actuated via axial holes in the interior of the shafts W3 and W9 the clutches K1, ..., K4. The oil pressure required for the control hydraulics is provided by a hydraulic pump 26 produced, the oil sucks on a downwardly directed intake from the forming in a trough of the housing base oil sump and over in the storage wall 23 Integrated channels for control forwards.

From the front storage wall 23 protrudes in the third, central axis provided with a serration input shaft or inner drive shaft W1, via which the power from the engine is coupled by means of an outer drive shaft mounted in the housing lower part in the transmission. Through the rear bearing wall which is also provided with a serration inner output shaft W7 is accessible, via which the power from the transmission can be delivered by means of an outer output shaft mounted in the lower housing part to the outside.

On the top of the lid 14 is the to the operation of the gear core 17 necessary transmission control so housed that of the transmission control 16 caused intervention in the transmission directly through the lid 14 A type of intervention is the adjustment of the hydrostat H1 and H2, which pivoting of the swivel housing by max. +/- 45 ° and affects the hydraulic connection between the two hydrostats. For adjusting (pivoting) of the hydrostats H1 and H2, an adjusting unit according to the invention is provided, whose embodiment in the 3 to 7 is shown.

The adjustment unit 16 is in part in one on the top of the lid 14 arranged, upwardly open housing 60 ( 2 ) housed that with a (second) cover 29 can be closed. To the case 60 are on opposite longitudinal sides in pairs opposite a total of four hydraulic working adjusting VZ1, VZ1 'and VZ2, VZ2' flanged outside, their associated adjusting VK1, VK1 'and VK2, VK2' in the housing 60 extend and swivel on the hydrostat H1 and H2 (see 7 ). The working in opposite directions adjusting cylinder of a pair of cylinders VZ1, VZ1 'and VZ2, VZ2' receive the pressure necessary for their operation via laterally arranged hydraulic channels 37 . 38 ( 4 ), via unillustrated connection channels in the housing 60 with hydraulic channels 32 , ..., 35 one in the second lid 29 integrated pressure distribution system 36 keep in touch. The pressure in the hydraulic channels 32 , ..., 35 the second lid 29 and thus the use of the pressurizable with the adjusting cylinder VZ1, VZ1 'or VZ2, VZ2' is controlled by hydraulic control valves (servo valves) SV1 and SV2, on the underside of the second lid 29 with their longitudinal axes 56 . 57 are flanged parallel and with pressure connections 54 . 55 ( 7 ) via corresponding vertical holes in the lid 29 with the hydraulic channels 32 , ..., 35 keep in touch.

The lid 29 extends in a plane perpendicular to the parallel pivot axes 27 . 28 the two hydrostat H1, H2 is oriented. In a parallel plane below the lid are pivotable two levers 45 . 46 arranged, by means of which the valve slide 58 . 59 the two control valves SV1, SV2 in the longitudinal axes 56 . 57 can be moved. These are the valve spools 58 . 59 in a central portion of the control valves SV1, SV2 freely accessible from above. The adjustment lever 45 . 46 are each on the valve pushers 58 . 59 pivotally mounted, wherein they protrude with about one-third of the lever length in the space between the two spaced-apart control valves SV1, SV2 and extend with about two thirds of the lever length in the opposite direction to the hydrostatic H1, H2.

Between the two control valves SV1, SV2 is an adjusting roller (cam roller) 42 arranged around a rotation axis 41 rotatable in two bearing blocks 43 . 44 is stored under the lid 29 are screwed. The rotation axis 41 the adjusting roller 42 runs parallel to the longitudinal axes 56 . 57 the control valves SV1, SV2. Is driven the adjusting roller 42 over a clutch disc 53 ( 6 ) from an electric motor 30 on the outside of the case 60 is flanged and by the control electronics or electrical system of the transmission 10 is controlled. Between the engine 30 and the adjusting roller 42 is a side exit, accessible from the outside emergency operation 31 provided by means of which the adjusting roller 42 (with still working hydraulics) can be manually rotated for emergency operation.

The adjusting roller 42 has guideways at its periphery 51 . 52 that of the adjusting levers 45 . 46 are scanned with the one (inner) ends. With the other (outer) ends, the adjusting levers with the upper bearing journals of the hydrostatic drives H1, H2 are each connected via a crank drive KT1 or KT2 (FIG. 7 ), wherein the coupling between the adjusting lever 45 . 46 and crank drive KT1, KT2 over one in a fork 47 slidable sliding block at the end of the lever 48 he follows. The crank mechanism KT1, KT2 is part of a swivel plate flanged to the hydrostatic H1, H2 49 . 56 connected to the hydrostat H1, H2 about its pivot axis 27 . 28 pivots, and at which the adjusting piston VK1, VK1 'and VK2, VK2' of the adjusting cylinder VZ1, VZ1 'and VZ2, VZ2' attack.

If with non-pivoting hydrostatic units H1, H2 the adjusting roller 42 is twisted, swing the lever 45 . 46 depending on the course of the guideways 51 . 52 around by the sliding blocks 48 going axes of rotation of the crank mechanisms KT1, KT2 and move accordingly the valve spool 58 . 59 the control valves SV1, SV2. If not with rotating adjusting roller 42 the hydrostats are pivoted, also move the valve spool 58 . 59 the control valves SV1, SV2. As a result, a mechanical feedback of the pivoting movement of the hydrostatic units H1, H2 is effected on the control of the adjustment process. The valve spool 58 . 59 are within the control valves SV1, SV2 by springs in the direction of the longitudinal axes 56 . 57 biased so that the adjustment lever 45 . 46 on one side of the guideways 51 . 52 the adjusting roller 42 without play. The control valves SV1, SV2 are arranged point-symmetrical to each other, so that only one valve type is needed.

By the inventive embodiment of the adjustment is a compact design, a precise control and a good accessibility achieved. In particular, the parallel Alignment of the longitudinal axes of the control valves and the axis of rotation of Adjusting roller perpendicular to the connecting line between the pivot axes the hydrostat and perpendicular to the pivot axes themselves leads to the fact that the adjustment mechanism builds very short.

10

transmission (stepless, hydrostatic, power split)

11

internal combustion engine

12

Stages planetary drive

13

web (Step planet wheel)

14

cover (Transmission)

15

flange (Cover)

16

adjustment

17

Gearing Principal

18 19

pivot bearing

20 21

support post

22

bearing housing

23

bearing wall

24 25

hydraulic control (Couplings)

26

hydraulic pump

27 28

swivel axis (HST)

29

cover (Adjustment)

30

engine (Control)

31

Emergency operation (manually)

32 ..., 35

hydraulic channel (Pressure distribution)

36

pressure distribution

37, 38

hydraulic channel (Adjusting cylinder)

39, 40

Control valve connection

41

axis of rotation (Adjustment roller)

42

adjusting roller (Barrel cam)

43 44

bearing block

45, 46

adjusting

47

fork

48

slide

49, 56

swivel plate

50

follower roll

51 52

guide groove

53

clutch disc

54 55

pressure connection

56 57

longitudinal axis (Control valve)

58 59

valve slide

60

casing (Adjustment)

H1, H2

hydrostats

K1, ..., K4

clutch

KT1, KT2

crankshaft

SK1, ..., SK4

reciprocating

SV1, SV2

control valve

SW

swivel angle (in %)

CC1, CC1 '

adjusting piston

CC2, CC2 '

adjusting piston

VZ 1, VZ 1 '

adjusting cylinder

VZ 2, VZ 2 '

adjusting cylinder

W1, ..., W12

wave

Z1, ..., Z12

gear

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2757300 A1 [0002]
• DE 2904572 C2 [0002]
• - DE 2950619 A1 [0002]
• - DE 3707382 A1 [0002]
• - DE 3726080 A1 [0002]
• - DE 3912369 A1 [0002]
• - DE 3912386 A1 [0002]
• DE 4343401 A1 [0002]
• - DE 4343402 A1 [0002, 0004]
• EP 0249001 B1 [0002]
• - EP 1273828 A2 [0002]
• - DE 19833711 A1 [0006]
• - DE 10044784 A1 [0006]
• US 2004/0173089 A1 [0006]

Cited non-patent literature

• - 2000 by H. Bork et al., "Modeling, Simulation and Analysis of a Continuously Variable Power Tractor Drive" [0006]

Claims (11)

Adjustment unit ( 16 ) for a continuously variable hydrostatic branched transmission ( 10 ), which transmission ( 10 ) comprises two hydrostatic units (H1, H2) arranged at a distance next to each other and each about a pivot axis ( 27 respectively. 28 ) are pivotally mounted, characterized in that the adjusting unit ( 16 ) hydraulically actuatable adjusting means (VZ1, VZ1 ', VZ2, VZ2') for pivoting the hydrostat (H1, H2) about their pivot axes ( 27 . 28 ), that control valves (SV1, SV2) for controlling the hydraulically actuatable adjusting means (VZ1, VZ1 ', VZ2, VZ2') and actuating means ( 30 ; 42 , ..., 46 ) are provided for actuating the control valves (SV1, SV2), and that the control valves (SV1, SV2) and the actuating means ( 30 ; 42 , ..., 46 ) are arranged between the two hydrostats (H1, H2). Adjusting unit according to claim 1, characterized in that the pivot axes ( 27 . 28 ) of the hydrostats (H1, H2) are aligned parallel to each other, that the control valves (SV1, SV2) longitudinal axes ( 56 . 57 ), along which for actuating the control valves (SV1, SV2) in each case a valve slide ( 58 . 59 ) is displaceable, that the control valves (SV1, SV2) are arranged at a distance from each other such that their longitudinal axes ( 56 . 57 ) parallel to each other and perpendicular to the pivot axes ( 27 . 28 ) of the hydrostats (H1, H2) are aligned, and that the actuating means ( 30 ; 42 , ..., 46 ) Adjustment lever ( 45 . 46 ), via which the control valves (SV1, SV2) are actuated, and which in a direction perpendicular to the pivot axes ( 27 . 28 ) of the hydrostats (H1, H2) lying pivot plane are pivotable. Adjusting unit according to claim 2, characterized in that the actuating means ( 30 ; 42 , ..., 46 ) an adjusting roller ( 42 ) arranged between the control valves (SV1, SV2) and about an axis of rotation ( 41 ) which is parallel to the longitudinal axes ( 56 . 57 ) of the control valves (SV1, SV2) is aligned, and which at its periphery guideways ( 51 . 52 ) for controlling the pivoting movement of the adjusting lever ( 45 . 46 ) having at one end the guideways ( 51 . 52 ) on the adjusting roller ( 42 ). Adjusting unit according to claim 3, characterized in that the adjusting lever ( 45 . 46 ) on the valve spools ( 58 . 59 ) are pivotally mounted and with their other ends with the Hydrostaten (H1, H2) are engaged, such that upon pivoting of the Hydrostaten (H1, H2) about their pivot axes ( 27 . 28 ) the adjusting levers ( 45 . 46 ) are pivoted in a predetermined manner in its pivoting plane. Adjusting unit according to claim 4, characterized in that the coupling between the adjusting levers ( 45 . 46 ) and the hydrostat (H1, H2) each one about the pivot axes ( 28 . 29 ) rotatable crank mechanism (KT1, KT2) includes. Adjusting unit according to claim 3, characterized in that the adjusting roller ( 42 ) from an electric motor ( 30 ) is driven. Adjusting unit according to claim 6, characterized in that for manual rotation of the adjusting roller ( 42 ) one between engine ( 30 ) and adjusting roller ( 42 ) arranged emergency operation ( 31 ) is provided. Adjusting unit according to claim 1, characterized in that the hydraulically actuable adjusting means for each hydrostat (H1, H2) comprise at least one adjusting cylinder (VZ1, VZ1 ', VZ2, VZ2'), which with an adjusting piston (VK1, VK1 ', VK2, VK2 ') at one about the pivot axis ( 27 . 28 ) pivotable pivot lever ( 49 . 50 ) of the hydrostat (H1, H2). Adjusting unit according to Claim 8, characterized in that two adjusting cylinders (VZ1, VZ1 ', VZ2, VZ2') working in opposite directions are provided for each hydrostat, which are preferably mounted on the same pivot lever ( 49 . 50 attack). Adjusting unit according to claim 1, characterized in that the control valves (SV1, SV2) for controlling the hydraulically actuatable adjusting means (VZ1, VZ1 ', VZ2, VZ2') and the actuating means ( 30 ; 42 , ..., 46 ) for actuating the control valves (SV1, SV2) in an upwardly open housing ( 60 ), which are provided with a lid ( 29 ) is closable, that the control valves (SV1, SV2) and selected actuating means ( 42 , ..., 46 ) on the underside of the lid ( 29 ), and that the control valves (SV1, SV2) with the hydraulically actuatable adjusting means (VZ1, VZ1 ', VZ2, VZ2') via a in the lid ( 29 ) integrated pressure distribution system ( 36 ) with individual hydraulic channels ( 32 , ..., 36 ) keep in touch. Adjusting unit according to claim 1, characterized that the hydrostats (H1, H2) optionally as a pump and as a motor work, and that their pivoting range is at least +/- 45 °.