Hydrostatic axial piston machine employing a bent-axis construction

Abstract

A bent-axis hydrostatic axial piston machine (1) has a drive shaft (4) rotatable around an axis of rotation (R.sub.t) and having a drive flange (3). A cylinder drum (7) is rotatable around an axis of rotation (R.sub.z). The cylinder drum (7) includes a plurality of piston bores (8) concentric to the axis of rotation (R.sub.z) of the cylinder drum (7) and in each of which piston bores (8) there is a longitudinally displaceable piston (10). The pistons (10) are fastened in an articulated manner to the drive flange (3). Between the drive shaft (4) and the cylinder drum (7) there is a constant velocity driving joint (30) in the form of a cone-beam semi-roller joint (31).

Claims

1. A hydrostatic axial piston machine utilizing a bent-axis construction, comprising: a drive shaft rotatable around an axis of rotation and provided with a drive flange; a cylinder drum rotatable around an axis of rotation offset from the axis of rotation of the drive shaft; a plurality of piston bores located in the cylinder drum and concentric to the axis of rotation of the cylinder drum; a longitudinally displaceable piston located in each piston bore, wherein the pistons are fastened in an articulated manner to the drive flange; and a driving joint between the drive shaft and the cylinder drum for rotationally synchronous rotation of the cylinder drum and of the drive shaft, wherein the driving joint comprises a cone-beam semi-roller joint, wherein the cone-beam semi-roller joint comprises at least one roller pair with two semi-cylindrical half-rollers, wherein the semi-cylindrical half-rollers are flattened along an axis of rotation separate from the axis of rotation of the drive shaft and the axis of rotation of the cylinder drum and the half-rollers form flat sliding surfaces on the flattened sides at which the half-rollers of the roller pair are in contact with each other to form a contact surface.

2. The hydrostatic axial piston machine as recited in claim 1, wherein the half-rollers are located inside the pistons in the radial direction and at a distance from the axes of rotation of the drive shaft and of the cylinder drum.

3. The hydrostatic axial piston machine as recited in claim 1, wherein each roller pair has a cylinder-drum-side half roller associated with the cylinder drum and a drive-shaft-side half-roller associated with the drive shaft.

4. The hydrostatic axial piston machine as recited in claim 3, wherein the cylinder-drum-side half-roller of a roller pair is located in a cylindrical or partly cylindrical cylinder-drum-side receptacle and the drive-shaft-side half-roller of a roller pair is located in a cylindrical or partly cylindrical drive-shaft-side receptacle.

5. The hydrostatic axial piston machine as recited in claim 4, wherein the respective half-roller located in a cylindrical receptacle is secured in the receptacle in the longitudinal direction of the axis of rotation of the half-roller.

6. The hydrostatic axial piston machine as recited in claim 5, wherein the half-rollers include a collar on the cylindrical section which is engaged in a groove of the receptacle.

7. The hydrostatic axial piston machine as recited in claim 4, wherein the drive shaft-side receptacles are located in the drive shaft or in the drive flange.

8. The hydrostatic axial piston machine as recited in one of the claim 4, wherein the drive shaft-side receptacle is located in a component that is connected in a torque-proof manner with the drive shaft.

9. The hydrostatic axial piston machine as recited in claim 4, wherein the cylinder-drum-side receptacle is located in the cylinder drum or in a sleeve-shaped driver element connected in a torque-proof manner with the cylinder drum.

10. The hydrostatic axial piston machine as recited in claim 9, wherein the driver element or the cylinder drum includes at least one finger-shaped protrusion that extends toward the drive shaft and in each of which there is a cylinder-drum-side receptacle for a cylinder-drum-side half-roller.

11. The hydrostatic axial piston machine as recited in claim 10, wherein the drive shaft or the drive flange or the component connected in a torque-proof manner with the drive shaft includes at least one pocket-shaped recess in which the driver element is engaged with at least one finger-shaped protrusion, and wherein in each pocket-shaped recess there is a drive shaft-side receptacle for a drive shaft-side half-roller.

12. The hydrostatic axial piston machine as recited in claim 3, wherein the axis of rotation of the drive shaft-side half-roller is inclined with respect to the axis of rotation of the drive shaft at an angle of inclination and intersects the axis of rotation of the drive shaft.

13. The hydrostatic axial piston machine as recited in claim 3, wherein the axis of rotation of the cylinder-drum-side half-roller is inclined by an angle of inclination with respect to the axis of rotation of the cylinder drum and intersects the axis of rotation of the cylinder drum.

14. The hydrostatic axial piston machine as recited in claim 3, wherein the axis of rotation of the drive-shaft-side half-roller is inclined with respect to the axis of rotation of the drive shaft by a first angle of inclination, wherein the axis of rotation of the cylinder-drum-side half-roller is inclined by a second angle of inclination with respect to an axis of rotation of the cylinder drum, wherein the first and second angles of inclination are identical and the axis of rotation of the cylinder-drum-side half-rollers and the axis of rotation of the drive-shaft-side half-roller of each roller pair intersect in a plane perpendicular to a line bisecting the angle between the axis of rotation of the drive shaft and the axis of rotation of the cylinder drum, and the half-rollers of a roller pair are located in a vicinity of the point of intersection of the axes of rotation of the half-rollers.

15. The hydrostatic axial piston machine as recited in claim 1, wherein the axial piston machine is operable in both directions of rotation, and wherein there is at least one roller pair for each direction of rotation for rotationally synchronous drive of the cylinder drum.

16. The hydrostatic axial piston machine as recited in claim 1, including a plurality of roller pairs distributed over a periphery.

17. The hydrostatic axial piston machine as recited in claim 1, wherein the at least one roller pair is located in the longitudinal direction of the cylinder drum outside the cylinder drum.

18. The hydrostatic axial piston machine as recited in claim 1, wherein the at least one roller pair is located in the longitudinal direction of the cylinder drum at least partly inside the cylinder drum.

19. The hydrostatic axial piston machine as recited in claim 1, wherein the drive flange is formed in one piece with the drive shaft, or the drive flange and the drive shaft are separate parts with the drive flange connected in a torque-proof manner with the drive shaft.

20. The hydrostatic axial piston machine as recited in claim 1, wherein between the drive shaft and the cylinder drum there is a spherical guide.

21. The hydrostatic axial piston machine as recited in claim 1, wherein the cylinder drum includes a longitudinal bore located concentric to the axis of rotation of the cylinder drum and through which a portion of the drive shaft extends through the cylinder drum.

22. The hydrostatic axial piston machine as recited in claim 21, wherein a sleeve-shaped driver element is located in the longitudinal bore of the cylinder drum.

23. The hydrostatic axial piston machine as recited in claim 1, wherein the drive shaft includes torque transmission means on both ends for the transmission of torque.

24. The hydrostatic axial piston machine as recited in claim 1, wherein the drive shaft comprises a hollow shaft, through which a transfer shaft that extends through the axial piston machine extends.

25. The hydrostatic axial piston machine as recited in claim 1, wherein the drive shaft is mounted in a housing on one side in a vicinity of the drive flange.

26. The hydrostatic axial piston machine as recited in claim 1, wherein the drive shaft is mounted in a housing on both sides of the cylinder drum.

27. The hydrostatic axial piston machine as recited in claim 1, wherein midpoints of articulated joints of the pistons located outside the cylinder drum in the longitudinal direction of the cylinder drum.

28. The hydrostatic axial piston machine as recited in claim 1, wherein midpoints of articulated joints of the pistons are located at least partly inside the cylinder drum in the longitudinal direction of the cylinder drum.

29. The hydrostatic axial piston machine as recited in claim 1, wherein the axial piston machine is a constant displacement machine with a fixed displacement volume.

30. The hydrostatic axial piston machine as recited in claim 1, wherein the axial piston machine is a variable displacement machine with a variable displacement volume, wherein an inclination of the axis of rotation of the cylinder drum with respect to the axis of rotation of the drive shaft is variable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages and details of the invention are described in greater detail below with reference to the exemplary embodiments illustrated in the accompanying schematic figures, in which like reference numbers identify like parts throughout.

(2) FIG. 1 is a longitudinal section of a first exemplary embodiment of a bent-axis machine of the invention;

(3) FIG. 2 shows a detail of FIG. 1 in the vicinity of the driving joint of the invention;

(4) FIG. 3 shows a section along line A-A in FIG. 2 with the transmission forces that occur on the driving joint for a first direction of rotation;

(5) FIG. 4 shows a section along line A-A in FIG. 2 with the transmission forces that occur on the driving joint for a second, opposite direction of rotation;

(6) FIG. 5 is a longitudinal section of a second exemplary embodiment of a bent-axis machine of the invention;

(7) FIG. 6 is a longitudinal section of a third exemplary embodiment of a bent-axis machine of the invention;

(8) FIG. 7 is a longitudinal section of a fourth exemplary embodiment of a bent-axis machine of the invention;

(9) FIG. 8 shows the driving joint between the drive shaft and the driver element of the cylinder drum in a three-dimensional representation;

(10) FIG. 9 is similar to FIG. 8 with the roller pairs of the driving joint with the cylinder drum removed;

(11) FIG. 10 is an illustration of the roller pairs in FIGS. 8 and 9;

(12) FIG. 11 illustrates the drive shaft of the driving joint of the invention in a three-dimensional representation;

(13) FIG. 12 illustrates the cylinder drum of the driving joint of the invention with the roller pairs in a three-dimensional representation; and

(14) FIG. 13 is a view as in FIG. 12 without the roller pairs of the driving joint of the invention.

(15) FIG. 14 is a longitudinal section view of the bent-axis machine of FIG. 1 including a hollow drive shaft.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(16) The hydrostatic axial piston machine 1 in the form of a bent-axis machine illustrated in FIG. 1 has a housing 2, which includes a housing pot 2a and a housing cover 2b. In the housing 2, a drive shaft 4 provided with the drive flange 3 is rotationally mounted by bearings 5a, 5b so that it can rotate around an axis of rotation R.sub.t. In the illustrated exemplary embodiment, the drive flange 3 is formed in one piece with the drive shaft 4.

(17) Located axially next to the drive flange 3 in the housing 2 is a cylinder drum 7 which is provided with a plurality of piston bores 8, which are arranged concentrically to an axis of rotation R.sub.z of the cylinder drum 7. In each piston bore 8, there is a longitudinally displaceable piston 10.

(18) The axis of rotation R.sub.t of the drive shaft 4 intersects the axis of rotation R.sub.z of the cylinder drum 7 at the intersection point S.

(19) The cylinder drum 7 is provided with a central longitudinal bore 11 which is concentric with the axis of rotation R.sub.z of the cylinder drum 7, and through which bore the drive shaft 4 extends. The drive shaft 4 routed through the axial piston machine 1 is supported by the bearings 5a, 5b, on both sides (bilateral) of the cylinder drum 7. The drive shaft 4 is supported by the bearing 5a in the housing pot 2a and by the bearing 5b in the housing cover 2b.

(20) The drive shaft 4 is provided on the drive flange side end with torque transmission means 12, such as splined gear teeth, for example, to transmit a drive torque or to tap an output torque. The opposite, cylinder-drum-side end of the drive shaft that extends through the axial piston machine 1 can also be provided with torque transmission means to make possible a transfer of torque through the axial piston machine 1. With the transfer, a torque can be transferred through the axial piston machine 1 or, on an axial piston machine 1 in the form of a hydraulic motor, can make possible a bilateral output of torque. There is a through hole 13 in the housing cover 2b for the drive shaft 4 which, in the illustrated exemplary embodiment, is closed by a cover 14.

(21) The axial piston machine illustrated in FIG. 1 is a constant displacement machine with a fixed displacement volume. The axis of rotation R.sub.z of the cylinder drum 7 is at a constant angle of inclination or pivot angle with respect to the axis of rotation R.sub.t of the drive shaft 4.

(22) For control of the feed and discharge of hydraulic fluid in the displacement chambers V formed by the piston bores 8 and the pistons 10, the cylinder drum 7 is in contact with a control surface 15 formed on the housing cover 2b the control surface is provided with kidney-shaped control bores (not illustrated in detail) and form an admission connection 16 and a discharge connection of the axial piston machine 1. For the connection of the displacement chambers V formed by the piston bores 8 and the pistons 10 with the control bores located in the housing cover 2b, the cylinder drum 7 is provided with a control opening 18 at each piston bore 8.

(23) The pistons 10 are each fastened to the drive flange 3 in an articulated manner. Between each piston 10 and the drive flange 3 there is an articulated joint 20 in the form of a spherical link. In the illustrated exemplary embodiment, the articulated joint 20 is in the form of a ball-and-socket joint formed by a spherical head 10a of the piston 10 and a spherical shell 3a in the drive flange 3 in which the piston 10 is fastened with the spherical head 10a.

(24) The pistons 10 each have a collar segment 10b, by means of which the piston 10 is located in the piston bore 8. A piston rod 10c of the piston 10 connects the collar segment 10b with the spherical head 10a.

(25) To make possible a compensating movement of the pistons 10 during rotation of the cylindrical drum 7, the collar segment 10b of the piston 10 is located in the piston bore 8 with some clearance or play. The collar segment 10b of the piston 10 can be spherical. To create a seal between the pistons 10 and the piston bores 8, sealing means 21, such as a piston ring, for example, are located on the collar segment 10b of the piston 10.

(26) For bearing and centering of the cylinder drum 7, there is a spherical guide 25 between the cylinder drum 7 and the drive shaft 4. The spherical guide 25 is formed by a spherical segment 26 of the drive shaft 4 on which is located the cylinder drum 7 with a segment 27 in the shape of a hollow sphere in the vicinity of the central longitudinal bore 11. The midpoint of the segments 26, 27 lies at the intersection S of the axis of rotation R.sub.t of the drive shaft 4 and the axis of rotation of the cylinder drum 7.

(27) On the axial piston machine 1 illustrated in FIG. 1, the midpoints M of the articulated joints 20 of the pistons 10 with the drive flange 3 in the longitudinal direction of the cylinder drum 7 are located completely outside the cylinder drum 7. The midpoints M of the articulated joints 20 are therefore always outside the longitudinal extension of the cylinder drum 7 during a rotation of the cylinder drum 7.

(28) To drive the cylinder drum 7 during operation of the axial piston machine 1, between the drive shaft 4 of the cylinder drum 7 there is a driving joint 30 that couples the drive shaft 4 and the cylinder drum 7 in their direction of rotation. The driving joint 30 is a constant velocity joint, which makes possible a rotationally synchronous drive of the cylinder drum 7 with the drive shaft 4, resulting in a uniform, synchronous rotation of the cylinder drum 7 with the drive shaft 4.

(29) The invention teaches that the driving joint 30 is a cone-beam semi-roller joint 31.

(30) The construction of the cone-beam semi-roller joint 31 with which the cylinder drum 7 and the drive shaft 4 are rotationally synchronously coupled is explained in greater detail below with reference to FIGS. 2 to 4 and 8 to 13.

(31) The cone-beam semi-roller joint 31 is formed by a plurality of roller pairs 50, 51, 52, 53, located between the drive shaft 4 and a sleeve-shaped driver element 40 which is connected in a torque-proof manner with the cylinder drum 7.

(32) The sleeve-shaped driver element 40 is located in the central longitudinal bore 11 of the cylinder drum 7. The driver element 40 is secured to the cylinder drum 7 in the longitudinal direction of the cylinder drum 7, in the axial direction, and in the peripheral direction. For axial securing, the driver element 40 is in contact with an end surface on a diametric shoulder 11a of the longitudinal bore 11. The driver element 40 is held in a torque-proof manner by securing means 45, which in the illustrated exemplary embodiment are formed by a connecting pin located between the sleeve-shaped driver element 40 and the cylinder drum 7. The drive shaft 4 routed through the axial piston machine 1 likewise extends through the sleeve-shaped driver element 40.

(33) Each of the plurality of roller pairs 50-53 of the cone-beam semi-roller joint 31 includes two semi-cylindrical half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b, which thus form pairs. The semi-cylindrical half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b (as indicated in FIG. 10) are each cylindrical bodies flattened along an axis of rotation RR.sub.t, RR.sub.z. On the flat sides, the half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b form planar sliding surfaces GF on which the two half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b of a roller pair 50, 51, 52, 53 are in contact with each other.

(34) The half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b are located in the radial direction inside the reference circle of the piston 10 and at a distance from the axes of rotation R.sub.t, R.sub.z. The cone-beam semi-roller joint 31 can be located compactly inside the reference circle of the pistons 10.

(35) Each roller pair 50-53 has one cylinder-drum-side half-roller 50a, 51a, 52a, 53a that belongs to or is associated with the cylinder drum 7 and one drive shaft-side roller 50b, 51b, 52b, 53b that belongs to or is associated with the drive shaft 4, which are in contact with each other at the planar sliding surfaces GF.

(36) The cylinder-drum-side half-rollers 50a, 51a, 52a, 53a of the corresponding roller pair 50-53 are each located in a cylindrical, in particular partly cylindrical, cylinder-drum-side receptacle 55a, 56a, 57a, 58a and the drive-shaft-side half rollers 50b, 51b, 52b, 53b of a roller pair 50-53 are each located in a cylindrical, in particular partly cylindrical, drive-shaft-side receptacle 55b, 56b, 57b, 58b.

(37) The half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b are each secured in the respective cylindrical receptacles 55a, 56a, 57a, 58a, 55b, 56b, 57b, 58b in the longitudinal direction of the corresponding axis of rotation.

(38) Each half-roller 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b is provided in the cylindrical section with a collar 60 which is engaged in a groove 61 of the corresponding receptacle 55a, 56a, 57a, 58a, 55b, 56b, 57b, 58b.

(39) In FIG. 2, the drive-shaft-side half-roller 50b of the roller pair 50 is drawn in thick lines and the cylinder-drum-side half-roller 50a that is in contact with the half-roller 50b is drawn in thin lines. The cylinder-drum-side half-roller 51a of the roller pair 51 is drawn in thick lines and the drive-shaft-side half-roller 51b that is in contact with the half-roller 51a is drawn in thin lines. The flattened, planar, sliding surfaces GF of the half-rollers 50b and 51a that lie in the plane of the section in FIG. 2 are illustrated.

(40) In the cone-beam semi-roller joint 31 (as illustrated in FIG. 2) the axes of rotation RR.sub.t of the drive-shaft-side half-rollers 50b, 51b, 52b, 53b are inclined at an angle of inclination with respect to the axis of rotation R.sub.t of the drive shaft 4. The axes of rotation RR.sub.t of the drive-shaft-side half-rollers 50b, 51b, 52b, 53b intersect the axis of rotation R.sub.t of the drive shaft 4 at the point of intersection S.sub.t. The individual axes of rotation RR.sub.t of the plurality of drive-shaft-side half-rollers 50b, 51b, 52b, 53b form a cone-beam, illustrated in FIG. 2, around the axis of rotation R.sub.t of the drive shaft 4 with the apex located at the point of intersection S.sub.t.

(41) The axes of rotation RR.sub.z of the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a are correspondingly inclined at an angle of inclination with reference to the axis of rotation R.sub.z of the cylinder drum 7. The axes of rotation RR.sub.z of the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a intersect the axis of rotation R.sub.z of the cylinder drum 7 at the point of intersection S.sub.z. The individual axes of rotation RR.sub.z of the plurality of cylinder-drum-side half-rollers 50a, 51a, 52a, 53a form a cone-beam illustrated in FIG. 2 around the axis of rotation R.sub.z of the cylinder drum 7, with the apex located at the point of intersection S.sub.z.

(42) The angles of inclination of the axes of rotation RR.sub.z of the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a with respect to the axis of rotation R.sub.z of the cylinder drum 7 and the axes of rotation RR.sub.t of the drive shaft side half-rollers 50b, 51b, 52b, 53b with respect to the axis of rotation R.sub.t of the drive shaft 4 are identical. The angles of inclination of the axes of rotation RR.sub.z, RR.sub.t of the half-rollers of the drive shaft 4 and cylinder drum 7 to be coupled to each other are therefore equal. Consequently, on the corresponding roller pairs 50-53, the axes of rotation RR.sub.t that belong to the drive shaft 4 and the axes of rotation RR.sub.z that belong to the cylinder drum 7 of the two half-rollers that form a roller pair intersect in pairs in a plane E which corresponds to the line bisecting the angle between the axis of rotation R.sub.t of the drive shaft 4 and the axis of rotation R.sub.z of the cylinder drum 7. The points of intersection SP that lie in the plane E, in which the respective axes of rotation RR.sub.t belonging to the drive shaft 4 intersect in pairs with the axis of rotation RR.sub.z belonging to the cylinder drum 7 of the two half-rollers that form a roller pair are illustrated in FIG. 2. The plane E is therefore inclined at one-half the angle of inclination or pivoting angle /2 with respect to a plane E1 which is perpendicular to the axis of rotation R.sub.t of the drive shaft 4 and a plane E2 which is perpendicular to the axis of rotation R.sub.z of the cylinder drum 7. The plane E passes through the point of intersection S of the axes of rotation R.sub.t, R.sub.z.

(43) The half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b of the respective roller pairs 50, 51, 52, 53 are located in the vicinity of the points of intersection SP of the axes of rotation RR.sub.t, RR.sub.z, as a result of which the transmission of force between planar sliding surfaces GF for the drive of the cylinder drum 7 takes place at the points of intersection SP of the two half-rollers of the respective roller pair 50-53.

(44) On account of the position of the points of intersection SP of the two half-rollers of the respective roller pairs 50-53 in the plane E that bisects the angle, the perpendicular radial distances r.sub.1, r.sub.2 of the points of intersection SP from the axis of rotation R.sub.t of the drive shaft 4 and from the axis of rotation R.sub.z of the cylinder drum 7 are equal. On account of the equal lever arms formed by the radial distances r.sub.1, r.sub.2 of the points of intersection, there are equal angular velocities 1 of the drive shaft 4 and 2 of the cylinder drum 7, as a result of which the cone-beam semi-roller joint 31 forms a constant velocity joint which makes possible an exactly rotationally synchronous drive and rotation of the cylinder drum 7.

(45) In operation of the axial piston machine 1, during rotation of the drive shaft 4, with an inclination of the axis of rotation R.sub.z of the cylinder drum 7 with respect to the axis of rotation R.sub.t of the drive shaft 4 at the angle of inclination or pivoting angle , a sliding of the two sliding surfaces GF of the two half-rollers of each roller pair 50-53 takes place. There is also a rotation of the respective semi-cylindrical half-roller around the respective axes of rotation RR.sub.t or RR.sub.z in the bed of the corresponding half-roller formed by the cylindrical receptacle 55a, 56a, 57a, 58a, 55b, 56b, 57b, 58b. On account of the inclination of the axes of rotation RR.sub.t, RR.sub.z of the half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b arranged in pairs with respect to one another, the planar surfaces and, thus, the sliding surfaces GF of the half-rollers in contact with each other can be oriented with respect to one another by rotation in the corresponding receptacles 55a, 56a, 57a, 58a, 55b, 56b, 57b, 58b.

(46) The axial piston machine 1 illustrated in FIG. 1 can be operated in both directions of rotation. To achieve a rotationally synchronous drive of the cylinder drum 7 in both directions of rotation, at least one roller pair 50-53 is provided for each direction of rotation and, thus, for each direction of torque of the drive torque for the drive of the cylinder drum 7.

(47) In the illustrated embodiment, the roller pairs 50, 51 are used to drive the cylinder drum 7 during a rotation of the drive shaft 4 in the counterclockwise direction. FIG. 3 shows, for this direction of rotation of the drive shaft 4, the forces F1, F2 which are transmitted at the planar sliding surfaces GF of the half-rollers 50a, 50b and 51a, 51b of the roller pairs 50, 51, which generate the drive torque M2 for the drive of the cylinder drum 7. By means of the drive shaft 4, the torque M1 is applied, and the force F1 is applied at the drive-shaft-side half-rollers 50b, 51b which, by means of the force F2 that occurs on the cylinder-drum-side half-rollers 50a, 51a, generate the drive torque M2 for the drive of the cylinder drum 7.

(48) In the illustrated exemplary embodiment, the roller pairs 52, 53 are used to drive the cylinder drum 7 in an opposite direction of rotation to the drive shaft 4 in the clockwise direction. FIG. 4 shows, for this direction of rotation of the drive shaft 4, the forces F1, F2 which are transmitted at the planar sliding surfaces GF of the half-rollers 52a, 52b and 53a, 53b of the roller pairs 52, 53 from the torque M1 acting on the drive shaft 4, which forces F1, F2 generate the drive torque M2 for the drive of the cylinder drum 7. By means of the drive shaft 4, the torque M1 is applied, and at the drive shaft side half-rollers 52b, 53b the force F1 is applied, which, by means of the force F2 that occurs on the cylinder-drum-side half-rollers 52a, 53a, generate the drive torque M2 for the drive of the cylinder drum 7.

(49) In the illustrated exemplary embodiment, there are two roller pairs 50, 51 and 52, 53 for each direction of rotation, respectively. The roller pairs 50, 51 for the first direction of rotation and the roller pairs 52, 53 for the second direction of rotation are uniformly distributed over the periphery. This arrangement makes possible an equalization of the radial forces. In the illustrated exemplary embodiment with two roller pairs for each direction of rotation, the roller pairs 50, 51 are offset by a rotational angle of 180 and the roller pairs 52, 53 are offset by a rotational angle of 180. The roller pairs 50, 51 for the first direction of rotation are offset from the roller pairs 52, 53 for the second direction of rotation by a rotational angle of 90.

(50) In the illustrated exemplary embodiment, the drive-shaft-side receptacles 55b, 56b, 57b, 58b for the drive shaft-side half-rollers 50b, 51b, 52b, 53b are located in the drive shaft 4. For this purpose, the drive shaft 4 is provided in the vicinity of the spherical segment 26 with pocket-shaped recesses 70, 71, 72, 73, on the side surfaces of each of which there is a drive-shaft-side receptacle 55b, 56b, 57b, 58b.

(51) In the illustrated exemplary embodiment, the cylinder-drum-side receptacles 55a, 56a, 57a, 58a for the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a are located in the sleeve-shaped driver element 40. The sleeve-shaped driver element 40 is provided with finger-shaped protrusions 41, 42, 43, 44, which extend toward the drive shaft 4 and in each of which there is a cylinder-drum-side receptacle 55a, 56a, 57a, 58a. The sleeve-shaped driver element 40 is also provided with the segment 27 in the form of a hollow sphere of the spherical guide 25.

(52) Each finger-shaped protrusion 41, 42, 43, 44 of the driver element 40 is engaged in an associated pocket-shaped recess 70, 71, 72, 73 of the drive shaft 4.

(53) In the axial piston machine 1 illustrated in FIG. 1, the roller pairs 50-53 of the cone-beam semi-roller joint 31 are located outside the cylinder drum 7 viewed in the longitudinal direction of the cylinder drum 7.

(54) FIGS. 5 to 7 illustrate additional exemplary embodiments of an axial piston machine claimed by the invention that employs a bent-axis construction, wherein components that are identical to those in FIG. 1 are identified by the same reference numbers. The exemplary embodiments illustrated in FIGS. 5 to 7 are the same as FIGS. 1 to 4 and 8 to 13 in terms of the construction of the cone-beam semi-roller joint 31 for the drive of the cylinder drum 7.

(55) The axial piston machine 1 illustrated in FIG. 5 is a variable displacement machine with a variable displacement volume. On the variable displacement machine, the angle of inclination of the axis of rotation R.sub.z of the cylinder drum 7 can be varied with respect to the axis of rotation R.sub.t of the drive shaft 4 to vary the displacement volume. The control surface 15 with which the cylinder drum 7 is in contact is for this purpose located on a rocker body 100 which is located in the housing 2 so that it can pivot around a pivoting axis SA. The pivoting axis SA of the rocker body 100 and, thus, of the cylinder drum 7 lies at the point of intersection S of the axis of rotation R.sub.t of the drive shaft and the axis of rotation R.sub.t of the cylinder drum 7 and is perpendicular to the axes of rotation R.sub.t and R.sub.z.

(56) Depending on the position of the rocker body 100, the angle of inclination of the axis of rotation R.sub.z of the cylinder drum 7 to the axis of rotation R.sub.t of the drive shaft 4 varies. The cylinder drum 7 can be pivoted into a null position in which the axis of rotation R.sub.z of the cylinder drum 7 is coaxial with the axis of rotation R.sub.t of the drive shaft 4. Starting from this null position, the cylinder drum 7 can be pivoted to one or both sides, so that the axial piston machine in FIG. 5 can be in the form of a unilaterally pivotable or bilaterally pivotable variable displacement machine. A device for the pivoting of the rocker body 100 and, thus, of the cylinder drum 7 is not illustrated in detail in FIG. 5.

(57) FIG. 6 shows one exemplary embodiment of the axial piston machine 1 in which the midpoints M of the articulated joints 20 of the pistons 10 with the drive flange 3 in the longitudinal direction of the cylinder drum 7 are located at least partly inside the cylinder drum 7. During rotation of the cylinder drum 7 the midpoints M of the articulated joints 20 are located at least partly inside the longitudinal extension of the cylinder drum 7. In FIG. 6, on the top piston 10 which is in the top dead center position in FIG. 6, a dimension L is indicated, by which the midpoints M of the articulated joints 20 project into the piston bores 8 of the cylinder drum 7. Finger-shaped protrusions 3b are formed on the end surface of the drive flange 3 facing the cylinder drums 7, on the ends of which the spherical shells 3a of the articulated joints 20 are located.

(58) The roller pairs 50-53 of the cone-beam semi-roller joint 31, seen in FIG. 6 in the longitudinal direction of the cylinder drum 7, are located at least partly inside the cylinder drum 7.

(59) The embodiment illustrated in FIG. 6 makes possible a compact construction of the axial piston machine 1 in the longitudinal direction of the drive shaft 4. There is also a larger open space between the drive shaft 4 and the cylinder drum 7. This larger open space can be utilized to enlarge the pivoting angle of the cylinder drum 7 and, thus, to increase the power density of the axial piston machine 1 and/or to enlarge the diameter of the drive shaft 4 and, thus, to increase the transfer torque.

(60) On the axial piston machine 1 illustrated in FIG. 7, instead of the bilateral mounting of the drive shaft 4 in the housing 2 illustrated in FIGS. 1, 5, and 6, the drive shaft 4 provided with the drive flange 3 is supported by two bearings 5a, 5b on one side and, is thus, supported in a cantilever fashion. The axial piston machine 1 in FIG. 7 is in the form of a variable displacement machine. It goes without saying that the axial piston machine can alternatively be in the form of a constant displacement machine. In the embodiment illustrated in FIG. 7, the cylinder drum 7 can be provided with the central longitudinal bore 11 for the passage of the drive shaft 4. However, the central longitudinal bore 11 of the cylinder drum 7 can also be omitted.

(61) An axial piston machine 1 with a cone-beam semi-roller joint 31 for driving the cylinder drum 7 has a series of advantages.

(62) The constant velocity joint in the form of a cone-beam semi-roller joint 31, with a corresponding choice of the angle of inclination of the axes of rotation RR.sub.z, RR.sub.t of the half-rollers, can be constructed in the form of a homokinetic constant velocity joint. The cone-beam semi-roller joint 31 which forms the constant velocity joint of the invention is suitable for use in axial piston machines 1 with a constant or variable displacement volume. In a variable displacement machine, no play results when the cylinder drum 7 pivots back to a reduced displacement volume. An additional significant advantage of the cone-beam semi-roller joint 31 is that the drive shaft 4 can be routed through the cylinder drum 7 and the axial piston machine 1 to create a torque transfer capability. The drive shaft 4 can be mounted on both sides of the cylinder drum 7 in the housing 2, which has advantages in terms of a compact construction of the axial piston machine 1 in the axial direction. The cone-beam semi-roller joint 31 has area contact. As a result of the area contact on the planar sliding surfaces GF of the two half-rollers of the roller pair 51-53, only low Hertzian stresses occur, as a result of which the cone-beam semi-roller joint 31 is not sensitive to and is robust in terms of its ability to withstand overloads which can occur, for example, as a result of high rotational acceleration. The cone-beam semi-roller joint 31 is therefore suitable for use in an axial piston machine 1, preferably a hydraulic motor, in applications with high rotational accelerations. On account of the low stresses that occur from the area contact on the planar sliding surfaces GF of the half-rollers, a surface treatment to protect against wear is necessary on the half-rollers only on the planar and flattened sliding surfaces GF. There is no need for a depth hardening of the half-rollers. As a result of the limited surface hardening of the half-rollers, which can be achieved by nitriding, for example, there is only a small change in the dimensions of the half-rollers so that a mechanical repair or finishing of the half-rollers is unnecessary. The low cost and the low amount of effort required for the manufacture of the half-rollers of the cone-beam semi-roller joint 31 results in little extra construction cost or effort for the axial piston machine 1 of the invention.

(63) On the axial piston machine 1 of the invention, the function of the torque drive of the cylinder drum 7 by the cone-beam semi-roller joint 31 and the function of the support of the cylinder drum 7 by the spherical guide 25 are separate. Both functions are simple and economical to achieve in terms of manufacturing on account of the geometrically simple surfaces and components required. In particular, the receptacles for the half-rollers of the cone-beam semi-roller joint 31 and the half-rollers themselves can be manufactured easily and economically.

(64) The invention is not restricted to the illustrated exemplary embodiments. The exemplary embodiment illustrated in FIG. 6 as a constant displacement machine can also be in the form of a variable displacement machine. In the embodiment illustrated in FIG. 7, the midpoints M of the articulated joints 20 can be alternatively located and immersed in the piston bore illustrated in FIG. 6. In addition, the axial piston machine illustrated in FIGS. 1, 5, 6, and 7, instead of an axial piston machine 1 that can be operated in both directions of rotation, can be an axial piston machine 1 that can be operated in a single direction of rotation, which simplifies the cone-beam semi-roller joint 31 accordingly.

(65) The cone-beam semi-roller joint 31 is not restricted to the illustrated number of roller pairs. It goes without saying that for higher drive torques M2 of the cylinder drum 7 to be transmitted, instead of two pairs of rollers for each direction of rotation, a higher number of roller pairs can be used. Correspondingly, for lower drive torques M2 of the cylinder drum 7 to be transmitted, only one single roller pair per direction of rotation can be provided.

(66) If the axial piston machine can only be operated in one direction of rotation, one roller pair or a plurality of roller pairs is required only for the desired direction of rotation to be able to transmit the drive torque M2 to the cylinder drum 7.

(67) The drive-shaft-side receptacles 55b, 56b, 57b, 58b for the housing and support of the drive-shaft-side half-rollers 50b, 51b, 52b, 53b, as an alternative to being located in the drive shaft 4, can be located in the drive flange 3 or in a component that is connected in a torque-proof manner with the drive shaft 4. The drive flange 3 and the drive shaft 4 can also be separate, in which case the drive flange 3 is connected in a torque-proof manner with the drive shaft 4 by appropriate torque transmission means, such as gear teeth. When the drive shaft 4 and the drive flange 3 are separate components, the drive-shaft-side receptacles 55b, 56b, 57b, 58b for the housing of the drive-shaft-side half-rollers 50b, 51b, 52b, 53b can also optionally be located in the drive flange 3 or the drive shaft 4.

(68) The cylinder-drum-side receptacles 55a, 56a, 57a, 58a for the housing and support of the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a, as an alternative to the configuration on the sleeve-shaped driver element 40, can be located directly on the cylinder drum 7, which is preferably provided with finger-shaped protrusions 41, 42, 43, 44.

(69) It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.