Universal Shaft with a Generator for Generating Electricity

Abstract

A universal shaft with a generator for generating electricity with the generator being driven by a cardan error occurring with a rotation of the universal shaft.

Claims

1. A shaft with a shaft body and a generator comprising a secondary part and a primary part arranged within said secondary part and movable relative to said secondary part, wherein said generator is provided on said shaft body in a rotationally fixed manner and that said primary part is movable along a direction of longitudinal extension of said secondary part, and wherein said direction of longitudinal extension of said secondary part is at a radial distance to a longitudinal axis of said shaft body.

2. The shaft according to claim 1, wherein said primary and said secondary part in a cross-sectional view of said shaft body in the region of an outer jacket of said shaft body extend in a circumferential direction that is tangential to a radial direction.

3. The shaft according to claim 2, wherein said secondary part comprises a curved coil connected in a rotationally fixed manner to said shaft body and said primary part comprises a magnet mounted in a spring-loaded manner deflectable within said coil in the circumferential direction of said shaft body.

4. The shaft according to claim 3, wherein windings of said coil are arranged eccentrically in said shaft body.

5. The shaft according to claim 3, wherein said generator extends substantially over an entire circumference of said shaft body in the cross-sectional view.

6. The shaft according to claim 1, wherein several generators are provided, each comprising a respective primary part with a natural frequency.

7. The shaft according to claim 6, wherein, in a cross-sectional view of said shaft body, at least one generator is provided in each half of said shaft body.

8. The shaft according to claim 1, wherein a logic evaluating electrical output of said generator for determining an operating parameter of said shaft mounted to be rotatable.

9. The shaft according to claim 1, wherein said generator is provided in a structural unit with a cylindrical sleeve introduced into said shaft body.

10. A drive train of a vehicle or a machine, comprising the shaft according to claim 1.

11. A method for operating a shaft with a shaft body and a generator provided in a rotationally fixed manner in said shaft body, the method comprising: moving a primary part of said generator relative to a secondary part of said generator; and swinging the primary part to and fro in a circumferential direction that is tangential to a radial direction of said shaft body when said shaft rotates or vibrates.

12. The method according to claim 11, wherein said primary part is excited in its natural frequency by the rotation of said shaft.

13. The method according to claim 11, wherein said shaft is a universal shaft and said primary part is excited in its natural frequency by a cardan error of said universal shaft.

14. The method according to claim 11, wherein a sensor provided on or in said shaft body and energized by said generator is switched on or off in dependence of an operating parameter of said shaft that is determined by a logic coupled to said generator by evaluating electrical output of said generator.

15. A universal shaft with a generator for generating electricity, wherein the generator is driven by a cardan error occurring with a rotation of said universal shaft.

16. The universal shaft according to claim 15, wherein said generator is configured as a vibratory system and can be excited by the cardan error in a natural frequency of said vibratory system.

17. The universal shaft according to claim 16, wherein a spring that is deflectable in a circumferential direction of said universal shaft for generating a relative motion between a primary part and a secondary part of said generator.

18. The universal shaft according to claim 17, wherein at least one of said primary part and said secondary part of said generator is attached to said universal shaft in a rotationally fixed manner.

19. The universal shaft according to claim 15, wherein said generator is provided in an interior of said universal shaft.

20. The universal shaft according to claim 15, wherein said generator is provided on an exterior of said universal shaft.

21. A drive train of a vehicle or a machine, comprising the universal shaft according to claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further details and advantages of the present invention arise from the following description of embodiments in conjunction with the drawing, in which:

[0033] FIG. 1 shows a schematic representation of a cross-sectional view of an universal shaft mounted to be rotatable of a first embodiment, and

[0034] FIG. 2 shows a schematic representation of a cross-sectional view of an universal shaft mounted to be rotatable of a second embodiment.

DESCRIPTION OF THE INVENTION

[0035] FIGS. 1 and 2 show embodiments schematically and in a cross-sectional view. The universal shaft mounted to be rotatable in these embodiments is configured as a hollow shaft with a shaft body 2 which has a cylindrical jacket 4. It is provided in a horizontal position; i.e. the universal shaft extends axially horizontally. Correspondingly, the weight force F.sub.G is shown with an arrow pointing downwardly. Shaft body 2 is rotatable about its central longitudinal axis A. It is referred to hereafter as axis of rotation A.

[0036] When the universal shaft rotates about the axis of rotation A at an angular velocity ω which points in the circumferential direction of the shaft body 2, a point of mass on the jacket 4 experiences a tangential acceleration α.sub.T which in its magnitude is the product of the distance between the point of mass from the axis of rotation A and the time derivative of the angular velocity ω. The tangential acceleration α.sub.T is perpendicular to the radial direction which points from the jacket surface of the jacket 4 in the direction of the axis of rotation A.

[0037] Two generators 6 are provided in the embodiment illustrated in FIG. 1, where one of the generators 6 is provided in the upper half of the shaft body 2 and the other generator 6 is provided in the lower half of the shaft body 2. The generator 6 has a primary part 8 and a secondary part 10, where the primary part 8 comprises a permanent magnet 12 which is attached to a curved nylon rod as a carrier 14. The carrier 14 extends along the direction of longitudinal extension L of the secondary part 10.

[0038] The permanent magnet 12 is composed of individual ring-shaped magnetic segments 16 which are shown only schematically in the figure by rectangles and are alternately strung together having different north pole-south pole orientations on the nylon rod. The carrier 14 is coupled at each of its ends to a leaf spring 18 which extends in the radial direction and is connected at the axis of rotation A to a web or bridge 20 of a carrier base. The carrier base is connected to the jacket 4 of the shaft body 2 in a rotationally fixed manner. The carrier base and/or the carrier 14 should be formed from the same material, in particular steel. Non-magnetic steel, for example austenitic steel or aluminum, are to be preferred in order to prevent magnetic interaction with the primary or the secondary part 10, 12.

[0039] Due to the resiliently flexibility of the leaf springs 18 and the inertia of its mass, the primary part 8 is an oscillatory system that can be excited by a rotation of the universal shaft and, in particular, a cardan error of the universal shaft. This means that the primary part 8 can be made to perform an oscillating motion which is composed of a motion in the direction of the direction of rotation of the universal shaft and a motion in a direction opposite to the direction of rotation of the universal shaft. This creates a relative motion between the primary part 8 and the secondary part 10 which comprises a coil 22 firmly connected to the jacket 4 of the shaft body 2. The coil 22 is wound concentrically around the carrier 14. The windings of coil 22 in the circumferential direction being the outer ones are attached to the jacket 4.

[0040] The deflection amplitude of the primary part 8 in the circumferential direction presently corresponds to half of the dual arrow P. The natural frequencies of the primary parts 8 of the generators 6 preferably differ.

[0041] The second embodiment shown in FIG. 2 differs from the first embodiment in that only one generator 6 or only one nylon rod is provided as the carrier 14 and which is bent to form a substantially circumferentially closed ring, and that the permanent magnet 12 and the coil 22 extend substantially over the entire circumferential direction of the jacket 4. Nylon is just one exemplary material for the production of the carrier. This carrier should be made of non-magnetic and flexible material. The configuration of the carrier 15 as a threaded rod is used to axially fix and preload the individual ring-shaped segments 16 on the carrier 14. The leaf springs 18 are arranged opposite one another and along a line which divides the shaft body 2 into an upper and a lower half. Alternatively, more than two leaf springs, for example, three to five leaf springs, can be arranged in a star shape to increase the transverse rigidity of the primary part. A circumferential gap in the coil 22 is selected precisely such that the leaf springs 18 do not touch the coils 22 when the primary part 8 deflects.

LIST OF REFERENCE CHARACTERS

[0042] 2 shaft body [0043] 4 jacket [0044] 6 generator [0045] 8 primary part [0046] 10 secondary part [0047] 12 permanent magnet [0048] 14 carrier [0049] 16 ring-shaped segment [0050] 18 leaf spring [0051] 20 web or bridge of the carrier base [0052] 22 coil [0053] A axis of rotation of the universal shaft [0054] L direction of longitudinal extension of the secondary part [0055] P twice the deflection amplitude [0056] F.sub.G weight force [0057] ω angular velocity [0058] α.sub.T tangential acceleration