Earthing contact and method for dissipating electric currents

Abstract

The invention relates to a ground terminal and to a method for discharging electric currents from a rotor part of a vehicle (such as a rail vehicle or the like, that has an axle) to a stationary stator part of the vehicle. The ground terminal includes a retaining device and a terminal element. The retaining device is connected to the stationary stator part of the vehicle in electrically-conductive manner, the terminal element is disposed on and connected to the retaining in electrically-conductive manner. The terminal element is made mostly of graphite and subjected to a contact force by means of a spring device of the retaining device to realize an electrically-conductive sliding contact between a sliding contact surface of the terminal element provided for realizing the sliding contact and a terminal surface of the rotor part. The terminal element has an arc-shaped cross-section at least in portions thereof, an outer surface of the cross-section forming the sliding contact surface at least in sections. The sliding contact surface abuts radially against the terminal surface of the rotor part.

Claims

1. A ground terminal configured to discharge electric currents from a rotor part of a vehicle having an axle to a stationary stator part of the vehicle, the ground terminal comprising: a retaining device and a terminal element, the retaining device having a spring device and being connected to the stationary stator part of the vehicle in an electrically-conductive manner, the terminal element having a sliding contact surface and being disposed on the retaining device and connected thereto in an electrically-conductive manner, wherein at least half of material of the terminal element is graphite—and the terminal element is subjected to a contact force by means of the spring device to form an electrically conductive sliding contact between the sliding contact surface and a terminal surface of the rotor part, wherein the terminal element has an arc-shaped cross section at least in sections of the terminal element, an outer surface of the arc-shaped cross section forming the sliding contact surface at least in sections thereof, the sliding contact surface being dimensioned to abut radially against the terminal surface of the rotor part, wherein the retaining device has a stationary base body, and wherein the retaining device comprises a bearing device configured to rotatably bear the base body on a radial inner surface of the rotor part, the bearing device comprising a rolling bearing or a sliding bearing.

2. The ground terminal according to claim 1, wherein the rotor part forms an circular ring-shaped cross section at an axial end of the axle, an inner surface of the circular ring-shaped cross section forming the terminal surface of the rotor part at least in portions thereof.

3. The ground terminal according claim 2, wherein the inner surface is realized by a recess on the axial end of the axle.

4. The ground terminal according to claim 2, wherein the inner surface is formed by a sleeve of the ground terminal, the sleeve being pressed into a recess on the axial end of the axle.

5. The ground terminal according to claim 1, wherein the axle is configured as a hollow shaft.

6. The ground terminal according to claim 1, wherein the terminal element is retained on a terminal element accommodation unit of the retaining device formed on the base body.

7. The ground terminal according to claim 6, wherein the retaining device includes a guiding device configured to movably guide the terminal element on the terminal element accommodation unit in the radial direction.

8. The ground terminal according to claim 6, wherein the terminal element accommodation unit forms a guide groove that extends radially on the base body, the guide groove accommodating and engaging a guide pin disposed on the terminal element or a protrusion formed on the terminal element.

9. The ground terminal according to claim 1, wherein the ground terminal comprises at least two terminal elements that are disposed coaxially on the base body with respect to a rotational axis of the axle.

10. The ground terminal according to claim 1, wherein the retaining device includes a connection device configured to connect the retaining device and the terminal element in an electrically-conductive manner, the connection device being formed by a protrusion of the base body and comprising a connection element by means of which a strand affixed to the terminal element is fastened to the protrusion.

11. The ground terminal according to claim 10, wherein the protrusion forms a distal end of the base body that is dimensioned to be disposed within a recess on an axial end of the axle.

12. The ground terminal according to claim 1, wherein the bearing device comprises a sealing disc that surrounds the base body at least partly, is connected to an axial end of the axle and seals a recess located on the axial end and dimensioned to receive the base body at least in part.

13. The ground terminal according to claim 1, wherein the bearing device comprises a torque support element by means of which the base body is fastened to the stationary stator part.

14. The ground terminal according to claim 13, wherein the torque support is a bar that is fastened to the base body in a torque-proof manner and via which the base body is connected to the stator part in an electrically-conductive manner.

15. The ground terminal according to claim 1, wherein the spring device has at least one spring element configured as at least one of a coil spring, a pressure spring, a leaf spring, a helical spring, and a diaphragm spring, the spring element being disposed on a pressurizing side of the terminal element facing away from the sliding contact surface.

16. A rail vehicle having a ground terminal according to claim 1.

17. A ground terminal configured to discharge electric currents from a rotor part of a vehicle having an axle to a stationary stator part of the vehicle, the ground terminal comprising: a retaining device and a terminal element, the retaining device having a spring device and being connected to the stationary stator part of the vehicle in an electrically-conductive manner, the terminal element having a sliding contact surface and being disposed on the retaining device and connected thereto in an electrically-conductive manner, wherein at least half of material of the terminal element is graphite—and the terminal element is subjected to a contact force by means of the spring device to form an electrically conductive sliding contact between the sliding contact surface and a terminal surface of the rotor part, wherein the terminal element has an arc-shaped cross section at least in sections of the terminal element, an outer surface of the arc-shaped cross section forming the sliding contact surface at least in sections thereof, the sliding contact surface being dimensioned to abut radially against the terminal surface of the rotor part, wherein the retaining device has a stationary base body, and wherein the retaining device includes a connection device configured to connect the retaining device and the terminal element in an electrically-conductive manner, the connection device being formed by a protrusion of the base body and comprising a connection element by means of which a strand affixed to the terminal element is fastened to the protrusion.

18. A ground terminal configured to discharge electric currents from a rotor part of a vehicle having an axle to a stationary stator part of the vehicle, the ground terminal comprising: a retaining device and a terminal element, the retaining device having a spring device and being connected to the stationary stator part of the vehicle in an electrically-conductive manner, the terminal element having a sliding contact surface and being disposed on the retaining device and connected thereto in an electrically-conductive manner, wherein at least half of material of the terminal element is graphite and the terminal element is subjected to a contact force by means of the spring device to form an electrically conductive sliding contact between the sliding contact surface and a terminal surface of the rotor part, wherein the terminal element has an arc-shaped cross section at least in sections of the terminal element, an outer surface of the arc-shaped cross section forming the sliding contact surface at least in sections thereof, the sliding contact surface being dimensioned to abut radially against the terminal surface of the rotor part, wherein the retaining device has a stationary base body, wherein the terminal element is retained on a terminal element accommodation unit of the retaining device formed on the base body, and wherein the terminal element accommodation unit forms a guide groove that extends radially on the base body, the guide groove accommodating and engaging a guide pin disposed on the terminal element or a protrusion formed on the terminal element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention is described in more detail by means of the drawing.

(2) FIG. 1 shows a longitudinal cut of a ground terminal;

(3) FIG. 2 shows a view from below of a terminal element;

(4) FIG. 3 shows a cut view of the terminal element from FIG. 4 along a line III-III;

(5) FIG. 4 shows a top view of the terminal element;

(6) FIG. 5 shows a back view of the terminal element.

(7) FIG. 1 shows a cut view of a ground terminal 10 having two terminal elements 11, terminal elements 11 being illustrated in more detail in FIG. 2 to FIG. 5. Ground terminal 10 serves for discharging electric currents from an axle (not further illustrated) of a vehicle or rather rail vehicle. Ground terminal 10 comprises a retaining device 12 for retaining terminal elements 11 of ground terminal 10, terminal elements 11 and retaining device 12 essentially being part of a stator part 13 of the vehicle (not further illustrated). Ground terminal 10 further comprises a sleeve 14 and a sealing disc 15 as part of a bearing device 16 of ground terminal 10 which are both connected to an axial end (not illustrated) of the axle and can thus be associated to a rotor part 17 of the vehicle. Sleeve 14 is pressed into a recess (not illustrated) on the axial end of the axle. Sealing disc 15 is tightly connected to sleeve 14 and/or the axle via indicated screws 18. Sleeve 14 has an inner surface 19 which realizes a terminal surface 20 of rotor part 17. Terminal elements 11 comprise a sliding contact surface 21 for abutting against terminal surface 20 so that an electrically conductive sliding contact 22 is formed between respective terminal element 11 and inner surface 19.

(8) Retaining device 12 comprises a base body 23 which is made of electrically conductive metal and forms a terminal element accommodation 24 for each terminal element 11. Terminal element accommodation 24 protects terminal element 11 from an axial displacement and forms a guiding device 25 for movably guiding terminal element 11 in a radial direction relative to a rotational axis 26. Guiding device 25 is realized on base body 23 by a guiding groove 27 and a guiding pin 28, which is inserted into a bore 29 in terminal element 11.

(9) Furthermore, two strands 30 are fastened to each terminal element 11 by means of cable lugs 31. Strand 30 is inserted into a bore 32 in terminal element 11 and fastened or affixed there by means of tamping powder. A protrusion 33 is integrally formed on base body 23 and a through bore 35 is formed on a distal end 34 of protrusion 33. Cable lugs 31 are tightly fastened to distal end 34 of protrusion 33 by means of a screw connection 36. An electrically conductive connection is produced between terminal ends 11 and base body 23 by a connecting device 37 realized such.

(10) Retaining device 12 comprises bearing device 16 for rotatably bearing base body 23 on radial inner surface 19, bearing device 16 comprising a rolling bearing 39. Bearing device 16 further comprises sealing disc 16 having a seal 40. Base body 23 is passed through sealing disc 15 and seal 40 closely abuts against a diameter 41 of base body 23. It is thus prevented that dirt and humidity can enter an inner space 42 of sleeve 14.

(11) Bearing device 16 further comprises a torque support 43 made of a bar 44. Bar 44 is fastened to an axial end 46 of base body 23 by means of a screw 45. Screw 45 is disposed eccentrically relative to rotational axis 26. An electric connection from base body 23 to an axle support of the rail vehicle can thus be easily produced via bar 44.

(12) To realize a contact force of respective terminal element 11 on inner surface 19, retaining device 12 comprises a spring device 47. Spring device 47 comprises a number of pressure springs 48 which are each inserted into a bore 49 in terminal element 11 opposite sliding contact surface 21. Pressure springs 48 are supported at base body 23 so that terminal elements 11 are each pressed against contact surface 20 by means of pressure springs 48 using contact force.

(13) Contact element 11 is made of graphite. Grooves 50 extending in the axial direction are formed in terminal element 11 or in sliding contact surface 21. Grooves 50 serve for reducing friction and heat and for deflecting brush dust. A continuous current of up to 250 A can be discharged using ground terminal 10.