EP1802867A1

EP1802867A1 - Hydrostatic axial piston machine and use of said machine

Info

Publication number: EP1802867A1
Application number: EP05791487A
Authority: EP
Inventors: Markus Liebherr; Josef HÄGLSPERGER; Peter Dziuba; Josef Bauer; Johann Federholzner
Original assignee: Markus Liebherr International AG
Current assignee: MALI MARKUS LIEBHERR INTERNATIONAL AG
Priority date: 2004-10-20
Filing date: 2005-10-20
Publication date: 2007-07-04
Also published as: US7661351B2; EA200700800A1; US20070261547A1; CN100529389C; BRPI0516387A; EA010848B1; JP2008517205A; WO2006042435A1; CN101044317A; CA2588231A1; KR20070067187A

Abstract

The invention relates to a hydrostatic axial piston machine (10) comprising a cylinder block (30) which can be rotated about a first axis (39), said cylinder block being provided with a plurality of cylinder bores (28) which extend in the axial direction and which are arranged on a partial circle which is concentric in relation to the first axis (39), in addition to a plane (12) which can be rotated about a second axis (38), whereon a number of pistons (27, 27'), which are immersed in a displaceable manner into the associated bores (28) and which correspond to the number of cylinder bores (28), can be articulated in a pivotable manner on a second partial circle which is concentric in relation to the second axis (38) and form a ring, in addition to means (19,..,25) for synchronising the rotation of the cylinder block (39) about the first axis (39) and the drive shaft (11 ) about the second axis (38). The cylinder block (39) and the drive shaft (11 ) can be adjusted in a continuous manner by means of both axes (38, 39), between a first position, wherein both axes are parallel (38, 39), and a second position, wherein both axes (38, 39) together form a maximum pivoting angle (a<sub

Description

DESCRIPTION

HYDROSTATIC AXIAL PISTON MACHINE AND USE OF ONE

SUCH MACHINE

TECHNICAL AREA

The present invention relates to the field of axial piston machines. It relates to a hydrostatic axial piston machine according to the preamble of claim 1 and the use of such a machine.

STATE OF THE ART

Stepless hydrostatic power split transmissions, especially in construction or agricultural vehicles, have long been known from the prior art (see, for example, the publications DE-AS-1 113 621, DE-C2-29 04 572, DE-A1-37 07 382 DE-A1-43 43 401 and EP-A1-1 195 542). In these transmissions, the transmitted power is dependent on the

Travel speed divided on a mechanical and a hydrostatic branch of the transmission, transmitted and then brought together again. The hydrostatic power transmission branch of the transmission usually comprises two hydrostatic axial piston machines, which are hydraulically connected to each other and of which one operates as a pump and the other as a motor. Depending on the driving level, the two machines can swap their roles.

The hydrostatic axial piston machines are an integral 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

Driving steps and the like .. Examples of such hydrostatic axial piston machines are disclosed in DE-A1-198 33 711 or DE-A1 -100 44 784. The mode of operation and theory of hydrostatic axial piston machines and of a power-split tractor system equipped therewith are described in a publication by TU Munich in 2000 by H. Bork et al.,

"Modeling, simulation and analysis of a continuously variable power split tractor" described.

In the hydrostatic axial piston machines, the cylinder block, in which the axial pistons are immersed, can be pivoted about the pivot flange, on which the axial pistons are pivotably mounted, by a pivoting angle from the axis-parallel basic configuration. Depending on the swivel angle, an axial piston machine operating as a pump delivers more or less volume per unit of time at a constant speed. In an axial piston engine operating as a motor, the swivel angle influences the output

Torque and speed. Due to the interaction of two working as a pump and motor axial piston machines in a power-split transmission, regardless of the engine speed of the driving internal combustion engine, the driving speed can be adjusted by the pivoting angle of the pump and motor are changed in a suitable manner. So it is possible for a tractor, for example, to keep the speed of the diesel engine constant in spite of changing speed and the engine in the cheapest Operate operating point, or optimally adapt the speed of the PTO shaft to the work task of the PTO-driven accessory.

The maximum possible swivel angle of the axial piston machine determines the operating range of the Axialkoibenmaschine and thus also the properties of the transmission. In previously known axial piston machines, the maximum pivoting angle is limited to values less than or equal to 45 °. This results in a limitation of the power and the range of variation. This also has the consequence that the power split transmission, in which the axial piston machines are used, are limited in efficiency, cover a limited speed range per gear and are relatively complex in construction and space requirements.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a hydrostatic Axialkoibenmaschine, which is characterized over the known axial piston machines by significantly improved properties, and leads to corresponding improvements in the transmission properties when used in a power split transmission.

The object is solved by the entirety of the features of claim 1. The core of the invention is to provide a maximum pivoting angle greater than 45 °, in particular greater than or equal to 50 ° in the Axialkoibenmaschine. Increasing the maximum swivel angle improves the efficiency of the machine. At the same time, the spread increases, ie, at constant speed results in an extended work area. In addition, with the same size, the power is increased or, with the same power, a reduced size is possible. These improvements in the single axial disk machine also lead to corresponding improvements in a power split transmission equipped with such machines. A preferred embodiment of the hydrostatic axial piston machine according to the invention is characterized in that the rotatable plane is arranged at one end of an output shaft rotating about the second axis, that the synchronizing means comprise a central synchronizing shaft arranged within the rim of the pistons, which at one end via a first joint with the output shaft and at the other end via a second joint with the cylinder block in a rotationally fixed engagement, and that the synchronizing to pivot a non-zero pivot angle in a arranged within the ring of the piston, the central funnel-shaped opening of the output shaft pivotable on all sides is such that the maximum tilt angle of the machine significantly by size and design of the. funnel-shaped opening and the cross section of the synchronizing is determined, wherein the first and second joint is formed in each case as a tripod joint, the synchronizing to compensate for changes in the distance at

Changes in the pivot angle is mounted axially displaceably in the drive shaft, and means are provided in the drive shaft, which bias the Synchronisierwelle toward the cylinder block resiliently, and wherein the biasing means comprise an axial compression spring, which via a pressure piston and a first, pivotally connected to the one end of the synchronizing shaft connected pressure pin exerts pressure, and the synchronizing shaft is supported at the other end via a second, pivotally connected to her pressure pin on the cylinder block.

In such a hydrostatic axial piston engine designed to increase the maximum pivot angle, preferably the funnel-shaped opening is locally widened locally between adjacent pistons by bulges, and the cross-sectional contour of the synchronizing shaft is adapted to the bulges. The bulges can basically have different shapes, provided that, in connection with the adapted cross-sectional contour of the synchronizing shaft, the synchronizing shaft can be pivoted more outwards. Especially It is favorable if, according to a preferred development, the edge contour of the funnel-shaped opening is a polygon with a number of pistons corresponding number of corners, and if the corners of the polygon are each arranged between adjacent pistons and form a bulge.

In particular, a divisible by 3 number of pistons may be provided, and the cross-sectional contour of the synchronizing shaft have a rotational symmetry, which passes by rotation by 120 ° in itself, wherein the 120 ° rotational symmetry of the cross-sectional contour of the synchronizing shaft by three extending in the axial direction, respectively Trough-shaped bulges arranged in a twisted manner at 120 ° are generated in the synchronizing shaft. 9 pistons are preferably provided.

A further embodiment of the inventive hydrostatic axial piston machine is characterized in that the pistons are each arranged at one end of a piston shaft, that the piston shaft tapers towards the other end and is pivotally mounted at the other end with a spherical head in a spherical bearing that the spherical Bearings are mounted on the second pitch circle in a formed on the output shaft flange which forms the plane rotatable about the second axis, and that the pistons, the piston shanks and the ball heads are each part of a one-piece element.

According to the invention, the hydrostatic axial piston machine according to the invention in a Leistungsverzweigungsgethebe by a

Internal combustion engine driven vehicle, in particular a tractor used, wherein a part of the Leistungszwezweigungsgethebe transmitted drive power is transmitted hydraulically, and for hydraulic power transmission at least two hydraulically interconnected hydrostatic axial piston machines are used, which operate alternately as a pump and motor. Further embodiments emerge from the dependent claims.

BRIEF EXPLANATION OF THE FIGURES

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it

1 shows a longitudinal section through a hydrostatic axial piston machine with unverschwenktem cylinder block according to a preferred embodiment of the invention.

Fig. 2 in a section of the hydrostatic axial piston machine

Figure 1 with the + 50 ° pivoted cylinder block.

Fig. 3 in a section of the hydrostatic axial piston machine

FIG. 1 with the cylinder block pivoted by -50 °; FIG.

4 shows in longitudinal section the enlarged view of the head part of the output shaft of the machine from FIG. 1 with the cutouts for the one tripod joint and the synchronizing shaft;

Fig. 5 shows the head part of the output shaft of Fig. 4 in plan view in

Axis direction;

Fig. 6 in several sub-figures a) to e) different views of

Synchronizing shaft of Figure 1 with the recesses on the shaft and formed at both ends pin for the Tripodengelenke, wherein Fig. 6a and b show side views, Fig. 6c shows a longitudinal section in the plane B-B of Fig. 6b, Fig.

Fig. 6d shows a cross section in the plane AA of Fig. 6a, and Fig. 6e shows a perspective side view; Fig. 7 is a plan view from above of the position of the synchronizing shaft in the funnel-shaped opening at the moment of rotation, where one of the groove-shaped recesses of the synchronizing shaft lies in width parallel to one of the sides of the 9-cornered funnel;

Fig. 8 is the abstract scheme of an exemplary

Power split transmission for a tractor with two optionally acting as a pump and motor hydrostatic axial piston machines according to FIG. 1-6;

9 is a greatly simplified transmission according to the scheme of Figure 8, but without a continuous PTO ..;

Fig. 10 in various subfigures Fig. 10 (a1) to Fig. 10 (c), the various shift positions of the transmission of FIG. 9 in the first forward driving stage (Fig. 10 (a1) -10 (a3)), in the second forward driving stage (Figs. 10 (b1) -10 (b3)) and in reverse (Fig. 10 (c)); and

11 shows the efficiency eta (curve A) and the percentage hydrostatic component of the power transmission (curve B) as a function of the travel speed v of the tractor with the power distribution gear according to FIGS. 8 to 10 at a transmission input power of 195 kW at 1800 rpm and one

Final speed of 62 km / h at 2100 rpm.

WAYS FOR CARRYING OUT THE INVENTION

In Fig. 1 is a longitudinal section of a hydrostatic axial piston machine with unverschwenktem cylinder block (pivot angle α = 0) according to a preferred embodiment of the invention shown. The hydrostatic axial piston machine 10 comprises an elongated output shaft 11, a cylinder block 30, a plurality of pistons 27 and a synchronizing shaft 23 for synchronizing the rotations of the output shaft 11 and cylinder block 30. The output shaft 11 is divided along its length into differently machined sections, the storage serve the shaft, the reception of transmission gears and the inclusion and operation of clutches when the hydrostatic axial piston machine 10 is part of a power split transmission, as shown schematically in Fig. 7 by way of example. _,

At one end, which faces the cylinder block 30, the output shaft 11 thickened and ends in a concentric to the axis 38 of the output shaft 11 flange 12. In the face of the flange 1.2 are on a pitch circle about the axis 38 gieichmässig distributed nine circular cylindrical bearing receivers 32nd milled (see also Figs. 4 and 5), in which spherical bearings 18 are used for the pivotable mounting of the piston 27. The axes of the bearing seats 32 are tilted radially outward by a few degrees (e.g., 5 °) relative to the axis 38 of the output shaft 11. The end face of the flange 12 is correspondingly processed sloping outwards, so that it extends in the region of the bearing receivers 32 perpendicular to the axes thereof.

In the center of the flange 12 is a funnel-shaped opening 13 is provided (Fig. 4, 5), which merges further in the interior of the output shaft 11 in a central, graduated in diameter bore 15. About the bore 15 and partially overlapping with the bore 15 are three by 120 ° twisted arranged, axis-parallel holes 14 are inserted into the output shaft 11, which are part of a first Tripodengelenks 22. Comparable bores are present in the cylinder block 30 and are part of a second Tripodengelenks 24. The two tripod joints 22 and 24 allow a rotationally fixed coupling of the synchronizing shaft 23 with the output shaft 11 and the cylinder block 30 while pivoting the cylinder block 30 relative to the flange 12 and Output shaft 11. The synchronizing shaft 23 is according to this purpose Fig. 6 at the two ends in each case with three rotated by 120 °, arranged radially oriented, cylindrical pin 34 which extend - in the case of the first Tripodengelenks 22 - from the central bore 15 through the laterally open overlap region in the adjacent holes 14 , A comparable engagement of the pins 34 takes place in the second Tripodengelenk 24. To reduce the game 34 rings 17 (Fig. 1) are raised on the pins, which are cambered on the outside.

When the cylinder block 30 is pivoted relative to the flange 12, the distance between the cylinder block 30 and the flange 12 to be bridged by the synchronizing shaft 23 changes. In order to be able to compensate for this change in distance, the synchronizing shaft 23 is in the region of the first tripod joint

22 slidably mounted in the axial direction. The synchronizing shaft 23 is seated with its end facing the cylinder block 30 pivotably on a first pressure pin 25 which is inserted into the cylinder block 30 and protrudes with a portion of its length from the cylinder block 30. So that the synchronizing shaft

23 in the second Tripodengelenk 24 with the cylinder block is not disengaged, it is pressed in the axial direction with a bias against the second pressure pin 25. To generate the bias is a housed in the bore 15 compression spring 19 which presses on an axially displaceable pressure piston 20 and a second pressure pin 21 on the synchronizing shaft 23. Pressure piston 20, pressure pins 21, 25 and synchronizing shaft 23 each have a central oil passage.

The (cylindrical) cylinder block 30 has on a pitch circle about its axis 39 nine evenly distributed axis-parallel cylinder bores 28 which - as well as the bearing seats 32 of FIG. 5 - each with an angular distance of 40 °. The cylinder bores 28, which have a diameter of about 26 mm in the example shown, are designed as blind bores from the side facing the flange 12. Into the cylinder bores 28 dip from this side, the piston 27, which are pivotally mounted in the flange 12. For this purpose, each piston 27 a elongated, downwardly tapered piston shaft 27 ', which merges at the lower end in a ball head 26, with which it is pivotally mounted in the associated spherical bearing 18. If the cylinder block 30 is pivoted upward from the position shown in FIG. 1 (pivoting angle α = 0), as shown in FIG. 2, the pistons 27 which lie above a center plane perpendicular to the drawing surfaces travel further into their cylinder bores 28 and compress or displace through an opening the medium therein, while the lying below the median plane piston 27 continue to drive out of their cylinder bores 28 and relax the medium therein or suck through an opening. If the cylinder block 30 is pivoted downward as shown in FIG. 3, the pistons 27 lying above and below the median plane interchange their rollers. The maximum piston stroke of the piston 27 is in the example shown about 93 mm.

If the output shaft 11 and thus the synchronizing shaft 23 and the cylinder block 30 are rotated about their respective axes 38 and 39 at a constant pivoting angle .alpha..sub.O, each of the new pistons 27 per revolution undergoes a complete stroke cycle, the upper and lower dead points respectively when the piston and cylinder bore (for α> 0, see Fig. 2) are in the upper and lower or (for α <0, see Fig. 3) in the lower and upper vertex of the rotary motion. The hydrodynamic axial piston machine 10 can operate as a hydraulic pump when a drive takes place via the output shaft 11 and a hydraulic medium is sucked in by the piston 27 extending out of the cylinder bore 28 and pushed out by the piston driving into the cylinder bore 28. The

Pump power in volume per revolution is the greater, the greater the pivot angle α. But it can also work as a hydraulic motor when the cylinders are each acted upon between the top dead center and the bottom dead center with a pressurized hydraulic medium and the resulting rotational movement is removed at the output shaft 11. The torque is greater, the greater the pivot angle α. On the other hand, if high speeds are to be achieved on the output shaft 11, the Swivel angle α can be made small. In a power split transmission 40, as schematically shown in Fig. 7, the hydraulic power branch is formed by two hydraulically connected hydrostatic axial piston H1 and H2 of the type shown in Fig. 1, which - depending on the speed range - either as a pump and as a motor work.

The limited by the piston 27 working space in the cylinder bores 28 is accessible through connection openings 29 from the outer end side of the cylinder block 30 ago. For controlling the individual cylinders is a non-illustrated in FIGS. 1 to 3 rotatable control disc with corresponding openings at which the cylinder block 30 with the outer end face via a slide bearing axially supported (for the radial bearing a bearing bore 31 is provided in the cylinder block 30 ). Details of such a control are known and can be found in the publications mentioned above. The same applies to the pivot mechanism, which is required to pivot the cylinder block 30 relative to the flange 12 by the desired pivot angle α.

The hitherto known hydrostatic axial piston machines, as described in the publications mentioned above, have a pivoting range which is limited by a maximum pivot angle α _max of 45 °. As a result, the piston stroke per cylinder is limited and thus - with the same size - also the adjustment range for the performance. This leads in particular to restrictions if the hydrostatic axial piston chambers are to be used in power split transmissions. In the hydrostatic axial piston machines according to the present invention, this limitation is canceled by maximum. Pivoting angle α _ma χ greater than 45 °, preferably of up to 50 °, be realized.

An essential limitation for the maximum swivel angle α _{max of} a hydrostatic axial piston machine according to FIGS. 1 to 3 is provided by the synchronizing mechanism between the output shaft 11 and the cylinder block 30 given. The synchronizing shaft 23 pivots when the cylinder block 30 is pivoted by the pivot angle α by about half the pivot angle out of the axis 38 of the output shaft. In order to create space for this pivoting, the funnel-shaped opening 13 is provided according to FIGS. 4 and 5 in the center of the arranged on a pitch circle bearing receptacles 32 whose

Opening angle determines the pivoting range of the synchronizing shaft 23. In the known hydrostatic axial piston machines, the opening 13 is conical. The width of the opening is then determined by a circle which is inscribed in the bearing receptacles 32. In the present solution, however, the existing between the adjacent bearing seats 32 space is exploited to increase the possible pivoting range of the synchronizing shaft 23. For this purpose, 5 bulges 33 are provided in the opening in the angular range between adjacent bearing receptacles 32 as shown in FIG., Which extend beyond the inscribed circle. At the same time, according to FIG. 6d, the cross-sectional contour of the synchronizing shaft 23 is deviated from the circle in such a way that, in cooperation with the bulges 33 in the opening 13, an enlarged pivoting range for the synchronizing shaft 23 results. The synchronizing shaft 23 thereby rolls, when the axial piston machine rotates, in the manner of a toothed wheel in a ring gear on the edge contour of the opening 13 provided with the bulges 33.

The edge contour of the opening 13 can be designed basically wave-shaped, the wave crests are between the bearing receivers 32 and the wave troughs are arranged directly at the bearing receivers 32. 5, the edge contour of the funnel-shaped opening 13 is preferably a polygon with a number of corners corresponding to the number of pistons 27, ie a 9-corner, wherein the corners of the polygon are each arranged between adjacent pistons 27 and bearing receivers 32 and one Form bulge 33. By contrast, the cross-sectional contour of the synchronizing shaft 23 has a rotational symmetry which changes into itself by rotation through 120 °. This 120 ° rotational symmetry is achieved by three groove-shaped recesses 35 extending in the axial direction, each rotated by 120 ° Synchronizing shaft 23 generates. The standing between the channel-shaped recesses ribs of the synchronizing shaft 23 dive into the bulges 33 of the opening 13 at a corresponding angular orientation of the tripod joint 22 synchronously, when the synchronizing at maximum swing angle α _max on the wall of the opening 13 rolls. Because of the 120 ° symmetry of the synchronizing shaft 23 and the 40 ° symmetry of the opening 13, the immersion takes place only at every third bulge 33. A snapshot of the rolling process, in which one of the channel-shaped recesses 35 of the synchronizing shaft 23 in the width straight parallel to a the sides of the 9-corner funnel 13 is located; is shown in Fig. 7.

Due to the extended pivoting range, the hydrostatic axial piston machine according to FIGS. 1 to 3 is particularly suitable for use in a power split transmission of a vehicle driven by an internal combustion engine (diesel engine), in particular a tractor, in which a high torque must be provided on the one hand in a low-speed region and on the other hand, higher speeds are to be enabled with good efficiency. The scheme of such a power take-off transmission is shown in Fig. 8, a highly simplified transmission according to the scheme of Fig. 8 shows Fig. 9 (the continuous PTO shaft 42 of Figure 8, however, replaced by an ending in Sttufenplanetengetriebe 45 drive shaft 56, as well missing the torsion damper 49). The illustrated power split transmission 40 is connected via a propeller shaft 41 and a torsion damper 49 with an internal combustion engine 50, which is symbolized by a piston-cylinder assembly. Through the power split transmission 40 passes through a PTO shaft 42 which is connected at one end directly to the propeller shaft 41 and at the other end via a coupling 46 with an output shaft 47 is connectable. By means of the output shaft 47 agricultural accessories can be driven in the case of the tractor. On the PTO shaft 42 sits the large sun z1 a stepped planetary gear 45, which additionally includes double planetary gears z2, z2 ', a small sun z1' and a ring gear z3. The small sun z1 'is rotatably connected via a hollow shaft with another gear z6, which meshes with a gear z7. The ring gear z3 is rotatably connected to a gear z4, which in turn meshes with a gear z5. The gear z5 can be connected via a clutch K3 to the output shaft 43 of a first hydrostatic axial piston machine H1. The gear z7 can be connected via a clutch K2 to the output shaft 44 of a second hydrostatic axial piston engine H2. The planetary carrier (55 in Fig. 8) of the double planet gears ^• z2, z2 'is non-rotatably connected to a gear z8, on the one hand meshes with a gear z9 and on the other hand with a gear z17. The gear z9 can be connected via a hollow shaft and a clutch K1 to the output shaft 44 of the second hydrostatic axial piston machine H2. The gear z17 is part of a drive train 48, which is in communication with the driven axles of the vehicle. In the transmission of FIG. 9, the power for vehicle propulsion can be taken from a corresponding output gear 54. The transmitted over the mechanical and hydraulic branch of the transmission power are summed on the planetary carrier 55 ^' . Furthermore sits on the PTO shaft 42 rotatably a gear z10, which can be connected via an intermediate gear z12 and another gear z11 by means of the clutch K4 with the output shaft 43 of the first hydrostatic axial piston H1.

The two hydrostatic axial piston H1 and H2 are hydraulically connected to each other via two hydraulic lines 51 and 52, which are each used as a forward and return line. A multi-way valve 53 inserted into the hydraulic lines 51, 52 makes it possible to interchange the lines when the two axial piston machines H1 and H2 exchange their roles, ie when the axial piston machine acting as a pump is to operate as a motor, and vice versa. The operation of the power split transmission 40 of FIG. 8 or FIG. 9 can be explained with reference to the partial figures of FIG. 10. The sub-figures a1 to a3 refer to a first forward gear, the sub-figures b1 to b3 to a second forward gear, and the sub-figure c refers to the reverse drive. For reasons of space, the names of the individual

Gear parts that are identical to the designations of Fig. 9, omitted.

At the beginning of the first forward drive (slow forward drive; Fig. 10 (a1)) are the clutches. K1 and K2 engaged. The first hydrostatic axial piston machine H1 operates in the first forward drive stage as a pump, the second hydrostatic axial piston engine H2 operates as a motor. The axial piston H1 (pump) is first from the unverschwenkten state (pivot angle α = 0) slowly in the fully pivoted state (pivot angle α = α _max ) pivoted, which is achieved in part figure Fig. 10 (a2). It pumps more and more hydraulic fluid into the engine

Axial piston machine H2. This is maximally pivoted and therefore gives off a high torque at slowly increasing rotational speed. When the axial piston machine H1 is pivoted to the maximum (FIG. 10 (a2)), the axial piston machine H2 is slowly pivoted back to zero (FIG. 10 (a3)). In this case, their speed increases, while the speed of the axial piston H1 and the transmitting hydraulic power at the end of the drive level goes back to zero. In Fig. 11, the first forward speed corresponds to the speed range between 0 and about 18 km / h, in which the proportion HP of the transmitted hydraulic power decreases linearly from 100% to 0%.

During the transition from the end of the first gear stage (FIG. 10 (a3)) to the beginning of the second gear stage (FIG. 10 (b1)), the clutch K1 is disengaged and the clutch K2 is engaged. Since the axial piston H2 absorbs no torque at pivot angle zero, the switching torque is virtually zero. Simultaneously with the operation of the clutches K1 and K2 is by switching the

Multi-way valve 53, the axial piston H1 in the engine operation and the axial piston H2 switched to pump operation. With another Now, the same processes as in the first speed step are carried out: First, the pump H2 is increasingly pivoted from the untwisted state (FIG. 10 (b1)) with the motor H1 fully pivoted, until it is also fully swiveled (FIG. 10 (b2) )). Then, the engine H1 is returned to zero (Fig. 10 (b3)), increasing its speed and reducing the transmitted hydraulic power to zero. The second forward speed corresponds to the speed range between 18 km / h and 62 km / h in Fig. 11. The proportion of transmitted hydraulic power increases from 0%, initially to a maximum of about 30% (at 30 km / h) and falls then at 0% (at about 53 km / h) and remains at 0% for the overlying speeds. According to FIG. 11, this type of transmission construction and the transmission control result in an efficiency eta of the transmission which increases very rapidly to values of over 85% at the beginning and even reaches its maximum of approximately 90% at the highest driving speeds.

For the reverse drive (Fig. 10 (c)), the clutches k2 and K3 are opened and the clutches K1 and K4 are closed. The axial piston H1 works as a pump and the axial piston H2 as a motor. The motor H2 is fully pivoted, while the pump H1 is pivoted from the pivoting angle zero.

LIST OF REFERENCE NUMBERS

10 hydrostatic axial piston engine (motor, pump) 11 output shaft

12 flange

13 opening (funnel-shaped)

14 hole (tripod joint)

15 hole (pressure device) 16 axial channel

17 ring

18 spherical bearing 9 compression spring 0 pressure piston

21, 25 push pin

22,24 tripod joint

23 synchronizing shaft

26 ball head

27 pistons

27 '. piston shaft

28 cylinder bore

29 connection opening (cylinder bore)

30 cylinder block

31 bearing bore

32 bearing receptacle

33 bulge

34 pin (tripod joint)

35 recess (channel-shaped)

36.37 storage trough

38 axis (output shaft)

39 axis (cylinder block)

40 power split transmission

41 PTO shaft

42 PTO

43,44 output shaft (axial piston machine)

45 stepped planetary gearbox

46 clutch

47 output shaft

48 powertrain

49 torsion damper

50 internal combustion engine

51, 52 hydraulic line

53 multiway valve

54 output gear 55 planet carrier

56 drive shaft

H1.H2 hydrostatic axial piston machine

K1 .... K4 Coupling z1, ..., z17 Gear α Swivel angle

Ornax maximum swing angle

Claims

A hydrostatic axial piston machine (10) comprising a cylinder block (30) rotatable about a first axis (39) and having a plurality of cylinder bores (28) extending concentrically on the first axis (39) and a cylinder bore (28) extending in the axial direction about a second axis (38) rotatable plane (12) on soft one of the number of cylinder bores (28) corresponding number of slidably dipping into the associated cylinder bores (28) piston (27, 27 ') on a to the second axis (38) concentric second pitch circle are pivoted and form a ring, and means (19, .., 25) for synchronizing the rotations of the cylinder block (39) about the first axis (39) and the output shaft (11) about the second axis (38) , wherein the cylinder block (39) and the output shaft (11) with its two axes (38, 39) between a first position in which the two axes are parallel (38, 39), and a second position in which the ^■ be iden axes (38, 39) form a non-zero maximum pivot angle (α _max ) with each other, are continuously adjustable, characterized in that the maximum pivot angle (α _max ) is greater than 45 °.

2. Hydrostatic axial piston machine according to claim 1, characterized in that the maximum pivoting angle (α _max ) is greater than or equal to 50 °.

3. Hydrostatic axial piston machine according to claim 1 or 2, characterized in that the rotatable plane (12) is arranged at one end of an about the second axis (38) rotating output shaft (11) that the synchronizing means (19, .., 25) a central synchronizing shaft (23) arranged within the rim of the pistons (27, 27 '), which at one end has a first joint (22) with the output shaft (11) and at the other end with a second joint (24) the cylinder block (30) is in a rotationally fixed engagement, and that the synchronizing shaft (23) for reaching a non-zero pivoting angle (α) in one within the rim of the piston (27, 27 ') arranged, the central funnel-shaped opening (13) of the output shaft (11) is pivotable on all sides, such that the maximum pivot angle (α _max ) of the machine is largely determined by the size and design of the funnel-shaped opening (13) and the cross section of the synchronizing shaft (23) ,

4. Hydrostatic axial piston machine according to claim 3, characterized in that the first and second joint each as Tripodengelenk (22, 24) is formed, that the Synchronisierwelle (23) to compensate for changes in distance with changes in the pivot angle (α) in the drive shaft (11 ) Is mounted axially displaceable, and in that in the drive shaft (11) means (19, 20, 21) are provided, which bias the synchronizing shaft (23) in the direction of the cylinder block (30) resiliently.

5. Hydrostatic axial piston machine according to claim 4, characterized in that the biasing means comprise an axial compression spring (19) which via a pressure piston (20) and a first, pivotally connected to one end of the synchronizing shaft (23) pressure pin (21) exerts pressure in that the synchronizing shaft (23) at the other end is supported on the cylinder block (30) via a second pressure pin (25) pivotally connected to it.

6. Hydrostatic axial piston machine according to one of claims 3 to 5, characterized in that to increase the maximum pivot angle (α _max ) the funnel-shaped opening (13) between adjacent pistons (27, 27 ') by bulges (33) is locally expanded, and that the cross-sectional contour of the synchronizing shaft (23) is adapted to the bulges (33).

7. Hydrostatic axial piston machine according to claim 6, characterized in that the edge contour of the funnel-shaped opening (13) is a polygon with a number of pistons (27, 27 ') corresponding number of corners, and that the corners of the polygon between each adjacent piston (27, 27 ') are arranged and form a bulge (33).

8. Hydrostatic axial piston machine according to claim 7, characterized in that a divisible by 3 number of pistons (27, 27 ') is provided, and that the cross-sectional contour of the synchronizing shaft (23) has a rotational symmetry, which by rotation of 120 ° in itself passes.

9. Hydrostatic axial piston machine according to claim 8, characterized in that the 120 ° rotational symmetry of the cross-sectional contour of the synchronizing shaft (23) by three axially extending, each rotated by 120 ° arranged trough-shaped bulges (35) in the synchronizing shaft (23) is generated ,

10. Hydrostatic axial piston machine according to claim 8 or 9, characterized in that 9 pistons (27, 27 ') are provided.

11. Hydrostatic axial piston machine according to one of claims 1 to 10, characterized in that the pistons (27) are each arranged at one end of a piston shaft (27 ') that the piston shaft (27 ¹ ) tapers towards the other end and the other End with a ball head (26) in a spherical bearing (18) is pivotally mounted, and that the spherical bearings (18) are mounted on the second pitch in a formed on the output shaft (11) flange (12) which surrounds the second axis (38) forms rotatable plane.

12. Hydrostatic axial piston machine according to claim 11, characterized in that the pistons (27), the piston shafts (27 ') and the ball heads (26) are each parts of a one-piece element.

13. Hydrostatic axial piston machine according to claim 4, characterized in that for the formation of the Tripodengelenke (22, 24) the Synchronizing shaft (23) at both ends in each case 3 by 120 ° rotated, extending in the radial direction, cylindrical pin (34).

14. The use of a hydrostatic axial piston machine (10) according to one of claims 1 to 13 in a power split transmission (40) of a driven by an internal combustion engine (50) vehicle, in particular a tractor, wherein a part of the power split transmission (40) transmitted drive power is transmitted hydraulically , and for hydraulic power transmission at least two hydraulically interconnected hydrostatic axial piston machines (W ^' , H2) are used, which operate alternately as a pump and motor.