ROTARY ENCODER AND METHOD OF OPERATING A ROTARY ENCODER

Abstract

The invention relates to a rotary encoder (10) for a machine, in particular a hoist, crane or the like, and to a method for operating a rotary encoder, the rotary encoder having a rotary encoder shaft (12) which is connectable to a shaft of a machine for detecting a rotation of the shaft, the rotary encoder having a frame (11) which is mountable on a machine, the frame (11) having an encoder element (13) disposed thereon for detecting a rotation of the rotary encoder shaft and a signal output element (14) for outputting a rotation angle signal and/or a speed signal, the rotary encoder having a bearing device (20) by means of which the rotary encoder shaft is rotatably mounted on the frame, the rotary encoder having an insulating device (19) which electrically insulates the rotary encoder shaft and the bearing device from the frame.

Claims

1. A rotary encoder (10) for a machine, the rotary encoder having a rotary encoder shaft (12) which is connectable to a shaft of a machine for detecting a rotation of the shaft, the rotary encoder having a frame (11) which is mountable on a machine, the frame (11) having an encoder element (13) disposed thereon for detecting a rotation of the rotary encoder shaft and a signal output element (14) for outputting a rotation angle signal or a speed signal, the rotary encoder having a bearing device (20) by which the rotary encoder shaft is rotatably mounted on the frame, wherein the rotary encoder has an insulating device (19) which electrically insulates the rotary encoder shaft and the bearing device from the frame.

2. The rotary encoder according to claim 1, wherein the insulating device (19) is configured such that currents induced in the shaft or the rotary encoder shaft (12) are interrupted from being discharged to the frame (11).

3. The rotary encoder according to claim 1, wherein the frame (11) is formed as a housing (15) in which the encoder element (13), the signal output element (14) and the bearing device (20) are accommodated.

4. The rotary encoder according to claim 1, wherein the bearing device (20) has at least one bearing.

5. The rotary encoder according to claim 4, wherein the at least one bearing is directly connected to the rotary encoder shaft (12).

6. The rotary encoder according to claim 4, wherein the bearing device (20) comprises a support element (22) which supports and at least partially surrounds the bearing or a plurality of bearings.

7. The rotary encoder according to claim 1, wherein the insulating device (19) is formed by a dielectric material which is disposed between the frame (11) and the bearing device (20).

8. The rotary encoder according to claim 7, wherein the dielectric material is plastic, insulating paper, mica or ceramic.

9. The rotary encoder according to claim 1, wherein the insulating device (19) is formed by a plurality of insulating elements (26, 27, 28, 29), the bearing device (20) being rigidly connected to the frame (11) via the insulating elements.

10. The rotary encoder according to claim 1, wherein the insulating device (19) is at least formed as a sleeve or a plate.

11. The rotary encoder according to claim 6, wherein the insulating device is formed by a dielectric material, the support element forming the insulating device.

12. A rotary encoder arrangement having a rotary encoder (10) according to claim 1 and a machine, the rotary encoder being connected to a shaft of the machine for detecting a rotation of the shaft.

13. A method for operating a rotary encoder (10) for a machine, a rotary encoder shaft (12) of the rotary encoder detecting a rotation of a shaft of the machine, said rotary encoder shaft (12) being connected to the shaft of the machine, an encoder element (13) of the rotary encoder being disposed on a frame (11) of the rotary encoder and detecting a rotation of the rotary encoder shaft, said frame (11) being fastened to the machine, a rotation angle signal or a speed signal being output by means of a signal output element (14) of the rotary encoder, the rotary encoder shaft being rotatably mounted on the frame via a bearing device (20) of the rotary encoder, wherein the rotary encoder shaft and the bearing device are electrically insulated from the frame by an insulating device (19) of the rotary encoder.

14. The method according to claim 13, wherein at least an electric signal or an electric potential is detected between the rotary encoder shaft (12) and the frame (11), between the bearing device (20) and the frame, between the shaft of a machine and the frame, or between the bearing device and the rotary encoder shaft by a measuring element of the rotary encoder (10).

15. The method according to claim 14, wherein an electric signal is generated by means of a measuring element and is conducted and measured via at least a bearing of the bearing device (20) or a bearing of the shaft of the machine.

16. The method according to claim 14, wherein the measuring element detects a change in the electric signal over an operation period, the measuring element determining and outputting a physical quantity of a bearing of the shaft of the machine, of the bearing device (20) or of an attachment of the machine.

Description

[0026] The FIGURE shows a longitudinal sectional view of a rotary encoder 10 which is essentially formed by a frame 11, a rotary encoder shaft 12, an encoder element 13 and a signal output element 14 (only schematically illustrated). Frame 11 is formed as a housing 15 which can be connected to a machine (not illustrated) via a flange of a first housing part 17. A second housing part 18 is screwed to first housing part 17.

[0027] Furthermore, rotary encoder 10 has an insulating device 19 and a bearing to device 20 for supporting rotary encoder shaft 12. Insulating device 19 is configured such that rotary encoder shaft 12 and bearing device 20 are electrically insulated from frame 11. Bearing device 20 comprises two rolling bearings 21 which are directly connected to rotary encoder shaft 12. Furthermore, bearing device 20 comprises a support element 22 which is partially formed sleeve-like and accommodates rolling bearing 21. Rolling bearings 21 are directly connected to support element 22 and disposed at a distance via a ring 23. Furthermore, support element 22 forms a flange 24, via which support element 22 is screwed to first housing part 17 by means of screws 25. Insulating device 19 is formed by a dielectric material, such as plastic, for example, and, in this case, formed by a first ring 26, a second ring 27, a plate 28 and a plurality of washers 29 for screws 25. In this way, support element 22 is fully electrically insulated from frame 11. A discharge of currents which might be induced in a shaft (not illustrated) of the machine and/or rotary encoder shaft 12 to frame 11 is thus interrupted. The design of encoder element 13, which is in this case formed by a plate 30 having increments (not shown), plate 30 being fastened on rotary encoder shaft 12, and by a detector (not shown) for detecting the increments, said detector being disposed on a circuit board 31, is not affected by the design of bearing device 20 and insulating device 19.