SYNCHRONIZING JOINT

Abstract

A joint for the angularly adjustable drive-connection of a cylinder block and a driveshaft of a hydrostatic bent axis piston unit. The joint has a shank which is rotatable about its longitudinal axis defining a joint axis, on both ends of the shank roller carriers project radially and basically perpendicular to the joint axis. On each roller carrier a roller is provided rotatable around a roller axis. The rollers are secured in axial direction against slipping-off of the roller carriers by means of an embossed area located axially outside of the roller on the respective distal end portion of the roller carrier.

Claims

1. A synchronizing joint for an angularly adjustable drive-connection of a cylinder block and a driveshaft of a hydrostatic bent axis piston unit, wherein the synchronizing joint has a shank which is rotatable about its longitudinal axis defining a joint axis, wherein on both ends of the shank roller carriers project radially and basically perpendicular to the joint axis, wherein on each roller carrier a roller is provided rotatable around a roller axis, and wherein the rollers are secured in axial direction against slipping-off of the roller carriers by means of an embossed area located axially outside of the roller on the respective distal end portion of the roller carrier, wherein the embossed area includes material added to the distal end portion of the roller carrier.

2. The synchronizing joint according to claim 1, wherein the embossed area is a welding point, a welding dash or a welding line along the circumferential direction of the roller carrier or a burr.

3. The synchronizing joint according to claim 1, wherein the embossed area is brought up by means of soldering, welding, sputtering, gluing or any other technology increasing locally the diameter of the roller carrier.

4. The synchronizing joint according to claim 1, wherein the synchronizing joint is embodied at least on one end as a tripod joint.

5. The synchronizing joint according to claim 1, wherein at each axial end of the shank concave seats for receiving connecting pins are formed.

6. The synchronizing joint according to claim 1, wherein the rollers are made of plastic material.

7. The synchronizing joint according to claim 1, wherein the external circumferential surface of the rollers shows a convex shape.

8. The synchronizing joint according to claim 1, wherein the roller carriers are integrally formed with the shank.

9. The synchronizing joint according to claim 1, wherein the shank comprises a longitudinal bore capable to guide lubrication fluid along the joint axis.

10. The synchronizing joint according to claim 9, wherein radial bores in the roller carriers connect radial to the roller axis oriented transversal bores in the roller carriers such that lubrication fluid from the longitudinal bore in the shank is capable to be guided to the rollers.

11. A hydrostatic bent axis piston unit having a cylinder block and a driveshaft connected by synchronizing joint according to claim 1, usable as hydrostatic bent axis piston pump or hydrostatic bent axis piston motor.

12. The hydrostatic bent axis piston unit according to claim 11, wherein each end of the shank comprises a concave seat for receiving connection pins, and wherein each end of the connection pins shows a convex or spherical head for being capable to support the synchronizing joint in an angular position with respect to the cylinder block axis and/or in angular position with respect to the driveshaft axis.

13. The hydrostatic bent axis piston unit according to claim 11, wherein the connecting pins comprise through holes capable to guide lubrication fluid from the cylinder block to the longitudinal bore in the shank and from the shank to the driveshaft and vice versa.

14. The hydrostatic bent axis piston unit according to claim 13, wherein radial bores in the driveshaft are capable to guide lubrication fluid from the connecting pins to shaft bearings rotatable supporting driveshaft in a housing of the hydrostatic bent axis piston unit.

15. The hydrostatic bent axis piston unit according to claim 11, wherein the hydrostatic bent axis piston unit is of the variable adjustable displacement type of construction.

16. The hydrostatic bent axis piston unit according to claim 15, wherein the cylinder block of the hydrostatic bent axis piston unit can be swivelled to positive and negative displacement angels by means of an adjustment unit.

17. A universal joint for an angularly adjustable drive-connection of two driveshafts, having a shank which is rotatable about its longitudinal axis defining a joint axis, wherein on at least one end of the shank a roller carrier projects radially and basically perpendicular to the joint axis, wherein on the at least one roller carrier a roller is provided rotatable around a roller axis, and wherein the roller is secured in axial direction of the roller axis against slipping-off of the roller carrier by means of an embossed area located axially outside of the roller on the distal end portion of the roller carrier, wherein the roller carriers are integrally formed with the shank.

18. The universal joint according to claim 17, wherein the embossed area is a welding point, a welding dash, a welding line or a burr along the circumferential direction of the roller carrier.

19. The universal joint according to claim 17, wherein the embossed area is brought up by means of laser application, soldering, welding, sputtering, gluing or any other technology increasing locally the diameter of the roller carrier.

20. The universal joint according to claim 17, wherein the universal joint is embodied at least on one end as a tripod joint.

21. The universal joint according to claim 17, wherein at each axial end of the shank concave seats for receiving connecting pins are formed.

22. The universal joint according to claim 17, wherein the rollers are made of plastic material.

23. The universal joint according to claim 17, wherein the external circumferential surface of the rollers shows a convex shape.

24. The universal joint according to claim 17, wherein the shank comprises a longitudinal bore capable to guide lubrication fluid along the joint axis.

25. The universal joint according to claim 24, wherein radial bores in the roller carriers connect radial to the roller axis oriented transversal bores in the roller carriers such that lubrication fluid from the longitudinal bore in the shank is capable to be guided to the rollers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention is shown below by the help of preferred embodiments of the above-mentioned synchronizing joint in more details which are shown in the attached Figures for exemplary purposes only and do not limit the scope of the invention, in particular not to the application of the inventive idea to synchronizing joints only. Further embodiments and modification of the embodiments and the inventive idea, which are within the knowledge of a person with skills in the relevant art are covered by the invention also, likewise combinations thereof. The Figures show:

[0026] FIG. 1 a hydrostatic bent axis axial piston unit according to one embodiment of the invention in a sectional cut;

[0027] FIG. 2 a synchronizing joint according to the invention in a perspective exploded view in the non-assembled state;

[0028] FIG. 3 a synchronizing joint in the assembled state in a sectional cut.

DETAILED DESCRIPTION

[0029] FIG. 1 illustrates a hydrostatic bent axis axial piston unit 1 according to the invention in the form of a hydraulic motor in a sectional view. The unit can fundamentally also be operated as a pump. The hydrostatic unit 1 has a cylinder block 6 which is mounted so as to be rotatable about its cylinder block axis 26 and has cylinder bores 7 distributed about its periphery, in which pistons 5 are movable. The cylinder block 6 is mounted in a housing 11 so as to be pivotable about a pivot axis which runs transversely with respect to its cylinder block axis 26, so that the cylinder block axis 26 of the cylinder block 6 forms an adjustable angle with the driveshaft axis 23 of the driveshaft 3 which itself is mounted transversally fixed and rotatable free in driveshaft bearings 10 mounted in the housing 11. The pistons 5 are articulately supported on the drive flange 4 of the driveshaft 3 at a settable angle. The adjustment of the displacement volume takes place by means of an adjusting device 9, by means of which a valve segment 8 which is attached to the cylinder block 6 can be pivoted.

[0030] The drive connection, i.e. the torque transmission between the cylinder block 6 and the driveshaft 3 is produced by means of a synchronizing joint 2 which is embodied exemplarily as a double tripod joint. Said synchronizing joint 2 has a substantially cylindrical shank 13 which is mounted at its ends in each case by means of rollers 17 in the drive flange 4 and in the cylinder block 6, and is biased against the drive flange 4 and the cylinder block 6 connecting pins 14 under spring loading by a pressure spring 15. In the driveshaft 3 and in the cylinder block 6 raceways 22 are formed for the rollers 17, which raceways 22 are designed such that the synchronizing joint 2 is displaceable in each case axially in the driveshaft 3 and axially in the cylinder block 6. For this purpose, the rollers 17 have a spherical outer shape. In this way, length compensation can take place for different pivot angles. The pressure spring 15 is installed in the driveshaft 3. The pressing force of said pressure spring 15 is transmitted via the two connecting pins 14 and the shank 13 of the synchronizing joint 2 to the cylinder block 6 in order to maintain a close contact of the upper end of the cylinder block 6 with the pressure plate 20 and the valve segment 8 even at low revolution speeds or even at standstill of the hydraulic unit 1.

[0031] As illustrated in the exploded view of FIG. 2, the synchronizing joint 2 which is embodied exemplarily as a double tripod joint, and is composed substantially of two three-arm stars and a cylindrical shank 13 which connects the two three-arm stars to one another. For this purpose, the shank 13 which is aligned in the direction of the joint axis 12 has at its two ends in each case three roller carriers 16 forming the three-arm star. The roller carriers 16 in each case define a roller axis 18, which is aligned in general perpendicular to the joint axis 12, for receiving the rollers 17 by means of which the synchronizing joint 2 is mounted at the one side in the driveshaft flange 4 of the driveshaft 3 and at the other side in the cylinder block 6. The synchronizing joint 2 is supported physically on one side to the cylinder block 6 and on the other side to driveshaft 3 by means of in each case one connecting pin 14 (not shown in FIG. 2) abutting each against a concave seat 24 formed at the end areas of the shank 13. The connecting pins 14, as shown in FIG. 1, are hold against the synchronizing joint 2 under the force of the pressure spring 15 (also not shown in FIG. 2) which is provided concentrically in the driveshaft 3. The roller carriers 16 are offset with respect to one another by in each case 120° and project perpendicularly from the shank 13.

[0032] It is obvious for a person skilled in the art that the double tripod depicts merely one possible embodiment for a synchronizing joint 2 and that various other possibilities of one-arm, two-arm, four-arm or more arm stars at the synchronizing joint 2 is viable, wherein a non-symmetrical design also viable, i.e. different numbers of arms on both sides of the shank 13. In order to prevent the rollers 17 from sliding-off the roller carriers 16 embossed areas 19 will be realized on each roller carrier 16 after the roller 17 is placed over the roller carrier 16. As FIG. 2 show an exploded view of the inventive synchronizing joint 2 and hence the rollers 17 are not placed already at their final destination, the embossed areas 19 (see FIG. 3) are still not applied. For applying the embossed areas 19 the axial length of the cylindrical roller carriers 16 is slightly bigger than the axial length of the rollers 17 such that the embossed areas 19 can be realized axially outside of the rollers 17—seen in axial direction of the roller carriers 16.

[0033] FIG. 3 shows the mounted—ready for assembling—state of the synchronizing joint 2 in longitudinal section. Illustrated are the roller carriers 16 which are formed integrally with shank 13 and to which the rollers 17 are attached in a displaceable fashion. Here, the rollers 17 are rotatable about the roller axis 18. With reference number 19 the embossed areas are depicted. This illustration of the embossed areas 19 is exaggerated and for illustration purposes only, in particular for the version where the embossed area is brought-up by laser application onto the distal end portion of the outer surface of the roller carriers 16, the embossed areas 19 would be very much smaller, just enough to prevent the rollers 17 from slipping-off. In this case the maximum radial height of the embossed area 18—seen perpendicular to the roller axis—would be, for instance, in the range of 0.1 mm to some tenth of mm only. Just enough to hold the roller 17 on the roller carrier 16 until the synchronizing joint 2 is assembled into the hydrostatic bent axis axial piston unit 1.

[0034] It is therefore possible during assembly for the synchronizing joint 2 to be handled as a modular unit without the risk that the rollers would slide-off of the roller carriers 16. The base body of the joint, i.e. the shank 13 with the roller carriers 16 can be produced as a single cast part or a forged part, as illustrated in FIG. 3. The embossed areas 19 on the roller carriers 16 as well as the roller 17 should be sufficiently stable to withstand the temperatures which occur in the power unit, and must be sufficient abrasion-resistant because any abrasion debris caused by the curved movement of the synchronizing joint 2 transmitted to the rollers 16 would pass directly into the system by means of the surrounding oil. The roller 17 can for example be produced from plastic material. Injection moulding could be suitable for the production process of the rollers 17. Metallic materials such as steel or bronze are likewise suitable and can be correspondingly processed in a punching and bending process.

[0035] The shank 13 comprises at both end sides a conical recess in form of a concave seat 24 in which, for instance, a spherical or conical head of the connecting pins 14 can abut. The longitudinal bore 27 in shank 13 ensures a sufficient supply with lubricating oil for the connecting pins 14 and further on to the slider 33 (see FIG. 1) which abuts against pressure spring 15. As best can be seen from FIG. 3 transversal bores 32 along the axial direction of the roller carriers 16, which are connected to the longitudinal bore 27 of the shank 13, provides for lubrication of the rolling movement of the rollers 17 on the roller carriers 16.

[0036] In summary the invention provides for a simple universal/synchronizing joint which due to its low number of parts is economic in its manufacturing and is as well robust during operation of, e.g., the hydrostatic bent axis axial piston unit or an axle of a vehicle with independent suspension. The inventive synchronizing joint also enables an automatic assembly of the inventive universal/synchronizing joint to the hydrostatic bent axis axial piston unit or the vehicle axle, as the rollers 17 are prevented from falling-down of the roller carriers 16 by means of embossed areas 19 brought up as stoppers for the rollers 17 at the distal ends of the roller carriers 16. Furthermore, as grease for “gluing” the rollers 17 to the roller carriers 16 is not necessary any longer, the hydraulic fluid in hydrostatic bent axis axial piston units will not be contaminated by grease and dirt wash-up from the synchronizing joint 2.

[0037] While the present disclosure has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this disclosure may be made without departing from the spirit and scope of the present disclosure.