Hydrostatic axial piston machine employing a bent-axis construction with a constant velocity joint for driving the cylinder drum

Abstract

A bent-axis hydrostatic axial piston machine (1) has a drive shaft (4) with a drive flange (3) rotatable around an axis of rotation (R.sub.t) and a cylinder drum (7) rotatable around an axis of rotation (R.sub.z). The cylinder drum (7) has a plurality of piston bores (8) concentric to the axis of rotation (R.sub.z) of the cylinder drum (7) and having longitudinally displaceable pistons (10) fastened in an articulated manner to the drive flange (3). Between the drive shaft (4) and the cylinder drum (7) there is a drive joint (30) (constant velocity joint) for rotationally synchronous rotation of the cylinder drum (7) and the drive shaft (4). The drive joint (30) and the cylinder drum (7) include a longitudinal bore (11) concentric to the axis of rotation (R.sub.z) of the cylinder drum, through which bore (11) the drive shaft (4) extends such that in the vicinity of the drive shaft (4) there is a torque transfer to a cylinder-drum-side end of the axial piston machine (1).

Claims

1. A hydrostatic axial piston machine utilizing a bent-axis construction, comprising: a drive shaft rotatable around a drive shaft axis of rotation and provided with a drive flange; a cylinder drum rotatable around a cylinder drum axis of rotation; 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 drive joint between the drive shaft and the cylinder drum, wherein the drive joint is a constant velocity joint for synchronous rotation of the cylinder drum and of the drive shaft, wherein the drive joint and the cylinder drum include a longitudinal bore concentric to the axis of rotation of the cylinder drum, and wherein the drive shaft provided with the drive flange extends through the cylinder drum via the longitudinal bore such that there is a torque transfer to a cylinder-drum-side end of the axial piston machine in the vicinity of the drive shaft, wherein the drive joint is a cone-beam semi-roller joint, wherein the cone-beam semi-roller joint includes at least one roller pair with two semi-cylindrical half-rollers, and wherein the semi-cylindrical half-rollers are flattened along an axis of rotation 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.

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

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

4. The hydrostatic axial piston machine as recited in claim 1, wherein the drive shaft is a hollow shaft through which a torque bar that is routed through the axial piston machine extends.

5. The hydrostatic axial piston machine as recited in claim 4, wherein the torque bar is not mechanically connected to the drive shaft.

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

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

8. The hydrostatic axial piston machine as recited in claim 7, wherein each respective half-roller located in a cylindrical receptacle is secured in the respective receptacle in the longitudinal direction of the axis of rotation of the half-roller.

9. The hydrostatic axial piston machine as recited in claim 8, wherein the half-rollers are provided on the cylindrical section with a collar engaged in a groove of the receptacle.

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

11. The hydrostatic axial piston machine as recited in one of the claim 7, wherein the drive-shaft-side receptacle is located in a component that is connected in a torque-proof manner with the drive shaft.

12. The hydrostatic axial piston machine as recited in claim 7, wherein the cylinder-drum-side receptacle is located in a sleeve-shaped driver element located in the longitudinal bore of the cylinder drum and is connected in a torque-proof manner with the cylinder drum, and wherein the drive shaft extends through the sleeve-shaped driver element.

13. The hydrostatic axial piston machine as recited in claim 12, wherein between the drive shaft and the sleeve-shaped driver element, there is a spherical guide formed by a sphere and a spherical shell for mounting of the cylinder drum.

14. The hydrostatic axial piston machine as recited in claim 12, wherein the driver element includes at least one finger-shaped protrusion which extends toward the drive shaft and in each of which there is a cylinder-drum-side receptacle for a cylinder-drum-side half-roller.

15. The hydrostatic axial piston machine as recited in claim 14, 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.

16. The hydrostatic axial piston machine as recited in claim 1, 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 a first angle of inclination and intersects the axis of rotation of the drive shaft, and wherein the axis of rotation of the cylinder-drum-side half-roller is inclined with respect to the axis of rotation of the cylinder drum at a second angle of inclination and intersects the axis of rotation of the cylinder drum.

17. The hydrostatic axial piston machine as recited in claim 16, 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 wherein the half-rollers of a roller pair are located in a vicinity of a point of intersection of the axes of rotation of the half-rollers.

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

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

20. 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 connected in a torque-proof manner.

21. 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.

22. A power split transmission with an axial piston machine as recited in claim 1.

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 is a longitudinal section of a second exemplary embodiment of a bent-axis machine of the invention;

(4) FIG. 3 is a longitudinal section of a third exemplary embodiment of a bent-axis machine of the invention;

(5) FIG. 4 is an enlarged detail from FIGS. 1 to 3 in the vicinity of the drive joint (in the form of a constant velocity joint);

(6) FIG. 5 shows a section along line A-A in FIG. 4 with the transmission forces that occur on the drive joint for a first direction of rotation;

(7) FIG. 6 shows a section along the line A-A in FIG. 4 with the transmission forces that occur on the drive joint for a second, opposite direction of rotation;

(8) FIG. 7 shows the drive joint between the drive shaft and the driver element of the cylinder drum in a three-dimensional representation;

(9) FIG. 8 shows the arrangement in FIG. 7 with the roller pairs of the drive joint with the drive joint removed;

(10) FIG. 9 is an illustration of the roller pairs in FIGS. 7 and 8;

(11) FIG. 10 is a three-dimensional representation of the drive shaft of the invention;

(12) FIG. 11 is a three-dimensional representation of the driver element of the drive joint with the roller pairs;

(13) FIG. 12 is a view as in FIG. 11 without the roller pairs of the drive joint, and

(14) FIG. 13 is a longitudinal section of a fourth exemplary embodiment of a bent-axis machine of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(15) The bent-axis hydrostatic axial piston machine 1 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 in one piece with the drive shaft 4.

(16) 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 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.

(17) 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.

(18) In the illustrated exemplary embodiment, the cylinder drum 7 includes a central longitudinal bore 11 that is concentric with the axis of rotation R.sub.z of the cylinder drum 7. The drive shaft 4 extends through the bore 11. 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.

(19) The drive shaft 4 is provided on the drive flange side-end with torque transmission means 12, such as splined gear teeth, 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 extends out of the housing cover 2b and has torque transmission means 13. The torque transmission means 13 on the shaft stub of the drive shaft 4 that extends out of the housing cover 2b are preferably in the form of splined gear teeth or a polygon profile or a feather key connection. The drive shaft 4 makes possible a transfer of torque through the axial piston machine 1. 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. For this purpose, there is a through hole 14 in the housing cover 2b for the drive shaft 4 that is concentric with the axis of rotation R.sub.t of the drive shaft 4.

(20) 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 displacement or pivot angle with respect to the axis of rotation R.sub.t of the drive shaft 4.

(21) 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 has 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 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.

(22) 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 connection 20 in the form of a spherical joint. In the illustrated exemplary embodiment, the articulated connection 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.

(23) 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.

(24) 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, are located on the collar segment 10b of the piston 10.

(25) 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 R.sub.z of the cylinder drum 7.

(26) 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 drive joint 30 that couples the drive shaft 4 and the cylinder drum 7 in their direction of rotation. The drive 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.

(27) The drive joint 30, which is in the form of a constant velocity joint and is not illustrated in any further detail is a cone-beam semi-roller joint 31.

(28) 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 described in greater detail below with reference to FIGS. 4 to 12.

(29) 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 connected in a torque-proof manner with the cylinder drum 7.

(30) 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 the 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. The inside diameter of the sleeve-shaped driver element 40 is provided with a contour that is in alignment with the longitudinal bore 11 of the cylinder drum 7.

(31) 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 form pairs. The semi-cylindrical half-rollers 50a, 50b, 51a, 51b, 52a, 52b, 53a, 53b (as indicated in FIG. 9) 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 plane 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.

(32) 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 and the drive shaft 4 so the transfer of the torque can be located radially inside the half-rollers of the cone-beam semi-roller joint 31.

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

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

(35) 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.

(36) 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.

(37) In FIG. 4, the drive-shaft-side half-roller 50b of the roller pair 50 is indicated in thick lines and the cylinder-drum-side half-roller 50a that is in contact with the half-roller 50b is indicated in thin lines. The cylinder-drum-side half-roller 51a of the roller pair 51 is indicated in thick lines and the drive-shaft-side half-roller 51b that is in contact with the half-roller 51a is indicated in thin lines. The flattened, planar, sliding services GF of the half-rollers 50b and 51a that lie in the plane of the section in FIG. 4 are illustrated.

(38) In the cone-beam semi-roller joint 31 (as illustrated in FIG. 4) 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.

(39) 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. 4) around the axis of rotation R.sub.t of the drive shaft 4 with the apex at the point of intersection S.sub.t.

(40) The axes of rotation RR.sub.z of the cylinder-drum-side half-rollers 50a, 51a, 52a, 53a are correspondingly inclined by 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 conical beam (illustrated in FIG. 4) around the axis of rotation R.sub.z of the cylinder drum 7, with the apex at the point of intersection S.sub.z.

(41) 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. 4. The plane E is 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.

(42) The half-rollers 50a, 50b, 51a, 51 b, 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 force transmission between the plane 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.

(43) 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 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 a precisely rotationally synchronous drive and rotation of the cylinder drum 7.

(44) In 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 and 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 plane 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.

(45) 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.

(46) 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. 5 shows, for this direction of rotation of the drive shaft 4, the forces F1, F2 which are transmitted at the plane 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, 51 a, generate the drive torque M2 for the drive of the cylinder drum 7.

(47) 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. 6 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.

(48) In the illustrated exemplary embodiment, there are two roller pairs 50, 51 and 52, 53 for each direction of rotation. 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.

(49) 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. 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.

(50) 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.

(51) 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.

(52) FIGS. 2 and 3 illustrate additional exemplary embodiments of an axial piston machine of the invention that employs a bent-axis construction. Components that are identical with those in FIG. 1 are identified by the same reference numbers. The exemplary embodiments illustrated in FIGS. 2 and 3 are identical with FIGS. 4 to 12 with regard to the construction of the cone-beam semi-roller joint 31 in the form of a constant velocity joint for the drive of the cylinder drum 7.

(53) On the axial piston machine 1 illustrated in FIG. 2, the drive shaft 4 is a hollow shaft provided with a longitudinal boring 100 which is concentric and coaxial with the axis of rotation R.sub.t. Located in the longitudinal boring 100, concentric to the axis of rotation R.sub.t, is a torque bar 105 which is routed through the drive shaft 4. By means of the torque bar 105, a torque Mt can be transmitted by a torque transfer through the axial piston machine 1. The torque bar 105 has no mechanical operative connection with the drive shaft 4. The drive shaft 4 and the torque bar 105 can therefore rotate at different speeds of rotation and/or in different directions of rotation.

(54) In the exemplary embodiment illustrated in FIG. 2, the drive shaft 4 is provided with torque transmission means 12 only on the drive flange side end and for the introduction or tapping of a drive torque. The cylinder-drum-side end of the drive shaft 4 is in the vicinity of the housing cover 2b.

(55) FIG. 3 illustrates an exemplary embodiment of an axial piston machine 1 in which the drive shaft 4 is analogous to the hollow shaft illustrated in FIG. 2 and with the coaxial longitudinal bore 100 through which the torque bar 105 is routed. The drive shaft 4 analogous to FIG. 1 is provided with torque transmission means 12 on the drive-flange-side end and with torque transmission means 13 on the cylinder-drum-side end that extends out of the housing cover 2b.

(56) An axial piston machine 1 of the invention with a constant velocity joint for the drive of the cylinder drum 7 and a torque transfer capability has a series of advantages.

(57) The constant velocity joint in the form of a cone-beam semi-roller joint 31 makes possible in a simple manner, as a result of the location of the half-rollers by means of the longitudinal bore 11, the ability to transfer a torque to the cylinder-drum side of the axial piston machine 1. The constant velocity joint in the form of a cone-beam semi-roller joint 31 can be constructed by a corresponding choice of the angle of inclination of the axes of rotation RR.sub.z, RR.sub.t of the half-rollers as a homokinetic constant velocity joint. The cone-beam semi-roller joint 31 which forms the constant velocity joint 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 plane 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 plane sliding surfaces GF of the half-rollers, only a surface treatment to protect against wear is necessary on the half-rollers on the flat 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 claimed by the invention.

(58) On the axial piston machine 1 claimed 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 manufacture 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.

(59) The invention is not restricted to the illustrated exemplary embodiments. The exemplary embodiments illustrated in FIGS. 1 to 3, as an alternative to the illustrated constant displacement machine, can also be in the form of a variable displacement machine. On a variable displacement machine, the angle of 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 can be adjusted to vary the displacement volume. The control surface 15 with which the cylinder drum 7 is in contact is for this purpose in the form of a rocker body, which is pivotably located in the housing 2.

(60) 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.

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

(62) 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.

(63) The axial piston machine 1 can be in the form of a hydraulic motor or in the form of a hydraulic pump.

(64) The torque transfer capability on the drive shaft 4 equipped with torque transmission means 12, 13 on both ends makes it possible, when the axial piston machine 1 is used as a hydraulic pump, to locate a plurality of hydraulic pumps one behind another and drive them by means of the transfer of the torque. The torque transfer capability on the drive shaft 4 equipped with torque transmission means 12, 13 on both ends makes it possible, when the axial piston machine 1 is used as a hydraulic motor, to locate a plurality of hydraulic motors one behind another and to increase the output torque a torque transfer. The torque transfer capability on the drive shaft 4 equipped on both ends with the torque transmission means 12, 13 makes it possible, on an axial piston machine 1 used as a hydraulic motor, to tap an output torque on both shaft ends of the drive shaft 4. This arrangement results in advantages in a traction drive, in which the drive shaft 4 is connected with different driven wheels or different driven axles of a vehicle.

(65) The construction of the drive shaft 4 as a hollow shaft with a torque bar 105 that runs through the hollow shaft makes it possible to achieve a torque transfer through the axial piston machine 1 by means of the torque bar 105, and by means of the torque bar 105, to transfer the torque Mt inside the axial piston machine 1 through the axial piston machine 1. The torque bar 105 and the drive shaft 4 can have different speeds of rotation and/or different directions of rotation. The transfer of a torque through the torque bar 105 located in the interior of the drive shaft 4 results in the universal applicability of the axial piston machine 1 and has particular advantages when the axial piston machine 1 is used in a power split transmission.

(66) 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.