ENCODER FASTENING FOR FASTENING AN ENCODER SHAFT TO A DRIVE SHAFT, AND CORRESPONDING METHOD

Abstract

An encoder fastening for fastening an encoder shaft of an encoder system to a drive shaft includes a spring washer configured for placement in a slot of the drive shaft, and a radially elastic element which is arranged on the spring washer to maintain a connection between the drive shaft and the encoder shaft under radial tension, when the encoder shaft is inserted into the slot of the drive shaft.

Claims

1.-17. (canceled)

18. An encoder fastening for fastening an encoder shaft of an encoder system to a drive shaft, said encoder fastening comprising: a spring washer configured for placement in a slot of the drive shaft; and a radially elastic element arranged on the spring washer to maintain a connection between the drive shaft and the encoder shaft under radial tension, when the encoder shaft is inserted into the slot of the drive shaft.

19. The encoder fastening of claim 18, wherein the radially elastic element is configured as leaf-like locking elements radially projecting from the spring washer.

20. The encoder fastening of claim 19, wherein the locking elements are bent.

21. The encoder fastening of claim 19, wherein the locking elements are spaced from each other.

22. The encoder fastening of claim 19, wherein the locking elements are configured as encoder locking elements and drive locking elements, said encoder locking elements and drive locking elements being aligned such as to oppose each other radially.

23. The encoder fastening of claim 22, wherein the encoder locking elements are bent in an axially opposite direction relative to the drive locking elements.

24. The encoder fastening of claim 22, wherein the drive locking elements are arranged on an encoder circumferential outer side of the encoder shaft such as to point radially outwards.

25. The encoder fastening of claim 22, wherein the encoder locking elements are arranged on a drive circumferential inner side of the drive shaft such as to point radially outwards.

26. The encoder fastening of claim 24, wherein the drive locking elements are connected to the drive shaft in a detachable or non-detachable manner.

27. The encoder fastening of claim 25, wherein the encoder locking elements are connected to the encoder shaft in a detachable or non-detachable manner.

28. The encoder fastening of claim 18, wherein the spring washer has an inner circumferential side defined by an inner diameter and an outer circumferential side defined by an outer diameter, said radially elastic element being configured as leaf-like locking elements which radially project from the spring washer and are configured as encoder locking elements arranged on the inner circumferential side and drive locking elements arranged on the outer circumferential side, said encoder locking elements and drive locking elements being aligned such as to oppose each other radially.

29. The encoder fastening of claim 28, further comprising a bridge connecting at least one of the drive locking elements to a corresponding one of the encoder locking elements.

30. The encoder fastening of claim 28, wherein the drive locking elements are bent in an axially opposite direction relative to the encoder locking elements.

31. The encoder fastening of claim 28, wherein the drive locking elements are connected to the encoder shaft in a detachable or non-detachable manner,

32. The encoder fastening of claim 28, wherein the encoder locking elements are connected to the drive shaft in a detachable or non-detachable manner.

33. The encoder fastening of claim 18, wherein the radially elastic element has a sprung characteristic.

34. A method for fastening an encoder shaft of an encoder system to a drive shaft, said method comprising: arranging a radially elastic element on a spring washer; placing the spring washer with the radially elastic element in a slot of the drive shaft; and partially inserting an encoder shaft into the slot of the drive shaft such that a connection between the drive shaft and the encoder shaft is maintained under radial tension.

Description

[0024] Further features, properties and advantages of the present invention are provided in the following description with reference to the appended schematic figures, in which:

[0025] FIG. 1 shows a partial longitudinal section of an electrical machine in the region of the encoder system as per the prior art,

[0026] FIG. 2 shows a front view of a first example of a first encoder fastening,

[0027] FIG. 3 shows a side view of the first encoder fastening,

[0028] FIG. 4 shows the first encoder fastening in the integrated state,

[0029] FIG. 5 shows a side view of a second example of a second encoder fastening.

[0030] Although the invention is illustrated and described in detail with reference to the preferred exemplary embodiment, the invention is not restricted by the examples disclosed herein. Variations can be derived by a person skilled in the art without thereby departing from the scope of patent as defined in the following claims.

[0031] FIG. 1 shows a partial longitudinal section of an electric machine 1 comprising an encoder system 13 which is attached at the end face and has an encoder lead 15. in this case, the electric machine 1 can represent one of the known machine types such as asynchronous machines or synchronous machines, or another type in which encoders are used. The stator 12 with its winding 2 and the rotor 3 with its drive shaft 4 essentially form the electric machine 1. The encoder system 13 including torque bracket 11 and bearing 5 is situated at the end face of the rotor 3. In this case, the encoder system 13 comprises an encoder shaft 10, which is connected to the drive shaft 4 by means of a fastening screw 9. The drive shaft 4 has a socket 8 for this purpose.

[0032] Since essential parts of the signal acquisition must be arranged centrally, a structure featuring a fastening screw 9 is however not suitable for signal acquisition. Furthermore, the fastening by means of a fastening screw 9 requires additional machining in the drive shaft 4 (thread.) and in the encoder shaft 10 (drilled hole), and not least a screw 9. The object of the invention is to be able to dispense with all these things, thereby making space available for central positioning of the signal acquisition.

[0033] According to the invention, the encoder fastening is now effected using a radially elastic element. In this case, the radially elastic element can have encoder locking elements 20a and drive locking elements 20b (FIG. 2).

[0034] In this case, the encoder fastening can be embodied as a spring washer 25 as shown in a first example (FIG. 2). The spring washer 25 has an inner circumferential side 21 with an inner diameter, the encoder locking elements 20a being arranged on said inner circumferential side 21. The spring washer 25 also has an outer circumferential side 22 with an outer diameter, the drive locking elements 20b being arranged on said outer circumferential side 22. In this case, the encoder locking elements 20a and the drive locking elements 20b are so arranged as to point in radially opposite directions.

[0035] In this case, the drive locking elements 20b and the encoder locking elements 20a are bent in axially opposite directions. The inner encoder locking elements 20a serve to securely hold the encoder shaft 10, while the outer drive locking elements 20b ensure the secure placement in the drive shaft 4. The bent arrangement of the drive locking elements 20b/encoder locking elements 20a ensures ease of assembly while locking in an opposite direction. The sprung characteristic ensures that the shaft-hub connection, formed by the drive shaft 4 and the inserted encoder shaft 10, is under radial tension in each case and therefore continues to function correctly.

[0036] FIG. 3 shows a side view of a spring washer 25 having drive locking elements 20b and encoder locking elements 20a. In this case, the drive locking elements 20b and encoder locking elements 20a can be connected together by a bridge 23. The drive locking elements 20b and encoder locking elements 20a can be offset relative to each other and arranged in a saw-tooth manner around the outer circumferential side 22 and inner circumferential side 21 respectively. In this case, the drive locking elements 20b and encoder locking elements 20a can be connected to both the drive shaft 4 and the encoder shaft 10 in a detachable or non-detachable manner. Likewise, the drive locking elements 20b and encoder locking elements 20a can be connected to the spring washer 25 in a detachable or non-detachable manner. In this case, the encoder locking elements 20a are bent in the direction of insertion of the encoder shaft 10 into a slot 30 of the drive shaft 4. The drive locking elements 20b are bent in the opposite direction to the direction of insertion of the encoder shaft 10.

[0037] FIG. 4 shows the spring washer 25 with drive locking elements 20b (FIG. 2) and encoder locking elements 20a (FIG. 2) in the integrated state. The spring washer 25 is installed in the slot 30 in this case. A tapered seat designated by the reference numeral 40 allows better centering of the encoder shaft 10 in this case.

[0038] FIG. 5 shows a further exemplary embodiment of the invention. The encoder shaft 10 here has an encoder circumferential outer side 26 with drive locking elements 20b, said drive locking elements 20b being arranged on the encoder circumferential outer side 26 and pointing radially outwards. In this case, the drive locking elements 20b here are bent against the direction of insertion of the encoder shaft 10 in the slot 30 of the drive shaft 4. This means that the drive locking elements 20b ensure the secure placement in the drive shaft 4. In this case, provision can also be made for attaching a plurality of such rings of drive locking elements 20b to the encoder circumferential outer side 26. A further exemplary embodiment consists in first introducing the encoder shaft 10 into a type of expanding anchor, wherein at least the expanding anchor is equipped with such drive locking elements 20b and is designed to be inserted with the encoder shaft 10 in the slot 30.

[0039] Provision can obviously also be made for encoder locking elements 20a which are arranged directly on the drive shaft 4 or on the drive circumferential inner side of the drive shaft 4 and which point radially outwards (not shown).