Device for monitoring a coupling coupling a first shaft to a second shaft

Abstract

The invention relates to a device (10) for monitoring a coupling of a first shaft (3) and a second shaft (31), having an optical unit (121) with a receiving element (14) designed to receive electromagnetic radiation, in particular light, a fault notification element (51), wherein the fault notification element (51) can be arranged on and / or in the first shaft (3) and on and / or in the second shaft (31), wherein the fault notification element (51) is designed to notify an asynchronous operation of the first shaft (3) relative to the second shaft (31). The invention also relates to a coupling (7) and a rotary electric machine (100).

Description

TECHNICAL FIELD

[0001] The invention relates to a device for monitoring a coupling shaft that couples a first shaft with a second shaft. BACKGROUND

[0002] Coupling shafts are critical components in drive systems, which can be damaged, for example, in the event of an overload.

[0003] For example, a coupling fault of a sensor with a motor is particularly critical in terms of safety, since there can be an incorrect reference signal for the controller, which in turn does not guarantee the safe operation of the motor. Furthermore, as a result of such a damage, the precise rotational speed specifications can no longer be adhered to.

[0004] In order to avoid damage to the coupling shaft, the individual or all components of the coupling shaft are usually designed oversized. However, this is very expensive. SUMMARY

[0005] The object of the invention is to improve this.

[0006] This object is achieved by the invention, namely a device for monitoring a coupling shaft that couples a first shaft with a second shaft, the device having:

[0007] - an optical unit with a receiving element, which is designed to receive electromagnetic radiation, in particular light,

[0008] - a fault notification element, wherein the fault notification element can be arranged on and / or in the first shaft and on and / or in the second shaft,

[0009] - wherein the fault notification element (51) is designed to notify an asynchronous operation of the first shaft (3) with respect to the second shaft (31).

[0010] The invention is suitable for various coupling shafts, for example coupling shafts that couple a mechanical shaft and a load, and coupling shafts that couple a sensor shaft and a mechanical shaft.

[0011] In particular, the invention can be applied to a servo motor. Servo motors are designed for work tasks that require a high degree of precision. For this purpose, it is particularly advantageous to know the integrity of the coupling shaft.

[0012] Electromagnetic radiation in the form of light is particularly well suited to the invention, as described below. Light is generally understood to mean the visible part of the electromagnetic spectrum in the range from 380 nm to 780 nm. Electromagnetic radiation in the non-visible range can also be used for the invention, in particular infrared light or ultraviolet light.

[0013] One embodiment is advantageous, according to which the front axial end of the fault notification element can be fastened at the first shaft, wherein the rear axial end can be fastened at the second shaft.

[0014] This offers the advantage that a retrofitting of existing machines is possible.

[0015] The fastening is effected, for example, by means of adhesion and / or screws.

[0016] One embodiment is advantageous according to which the failure notification element is designed in such a way that it can be severed or broken off in the case of an asynchronous operation of the first shaft relative to the second shaft.

[0017] This is achieved particularly advantageously by means of a pre-breakage point.

[0018] However, a pre-breakage point is not absolutely necessary. The failure notification element can also have a material which breaks off when the shafts are asynchronous.

[0019] However, the failure notification element can also notify a failure (i.e. an asynchronous operation) in other ways. For example, the failure notification element can bend and / or twist when asynchronous. Other changes are also possible.

[0020] The one or more shafts are advantageously embodied as hollow shafts. The failure notification element advantageously has a size which enables the failure notification element to be arranged inside the hollow shaft.

[0021] The exemplary diameter of the failure notification element is between 1 mm and 20 cm, advantageously between 5 mm and 10 cm.

[0022] One embodiment is advantageous according to which the failure notification element is designed in such a way that, during the operation of the first shaft and the second shaft, a first fracture surface of a first part of the failure notification element caused by severing and / or breaking off and a second fracture surface of a second part of the failure notification element caused by severing and / or breaking off rub against one another, so that radiation, preferably light, can be emitted, in particular by means of frictional luminescence.

[0023] The term frictional luminescence describes the emission of light, in particular cold light, which occurs when a solid is subjected to mechanical stress. The term is generally understood more broadly and, for example, luminescence also forms part of the term.

[0024] In the case of luminescence, a physical system enters an excited state by means of energy supplied from the outside and emits light (including radiation outside the visible range) by emitting photons when it transitions to its ground state.

[0025] The invention is suitable for emitting radiation, preferably light, by means of luminescence and by means of frictional luminescence.

[0026] The invention also comprises the following effects:

[0027] Radiation is emitted on the basis of fluorescence when no activation process takes place between energy absorption and emission.

[0028] When the excited intermediate state is able to freeze the energy for a while, radiation is emitted based on phosphorescence.

[0029] An embodiment is advantageous according to which the fault notification element has plastic.

[0030] An embodiment is advantageous according to which the fault notification element has polytetrafluoroethylene (PTFE) and / or polydimethylsiloxane (PDMS).

[0031] An embodiment is advantageous according to which the fault notification element has ZnS:Cu+PTFE.

[0032] An embodiment is advantageous according to which the fault notification element has ZnS:Cu+PDMS+PTFE.

[0033] An embodiment is advantageous according to which the fault notification element has ZnS:Cu+PDMS.

[0034] ZnS:Cu is zinc sulfide doped with copper.

[0035] It is advantageous for the phosphor to be embedded in a plastic film.

[0036] Stretchable hybrid bilayer light-emitting composites based on a combination of stretch- and triboelectricity-induced electroluminescence are particularly well suited.

[0037] An embodiment is advantageous according to which the fault notification element has a reflective element, in particular a mirror.

[0038] The reflective element is advantageously arranged at least substantially in the region of the axial end of the fault notification element. Other arrangements are also conceivable.

[0039] An embodiment is advantageous according to which the device has an emission element. The emission element is preferably designed as a light-emitting diode.

[0040] A light-emitting diode is advantageous because it is inexpensive and robust.

[0041] An embodiment is advantageous according to which the receiving element is designed as a photodiode.

[0042] A photodiode is advantageous because it is inexpensive and robust.

[0043] However, the receiving element can also be a photodetector. Other forms are also possible.

[0044] One implementation is advantageous in which the receiving element is designed to receive either emitted or reflected radiation.

[0045] One implementation is advantageous in which the receiving element is designed to detect changes in reflection characteristics.

[0046] The reflective properties advantageously relate to the reflection of ambient light and / or diffuse directional light and / or specular directional light.

[0047] The solution to the above objective is also achieved by the present invention, namely, a coupling having such a device.

[0048] The solution to the above objective is further achieved by the present invention, namely a rotary motor comprising: a first shaft; a second shaft, wherein the first shaft and the second shaft are connected by means of a coupling; and such a device.

[0049] One implementation is advantageous in which the first shaft and / or the second shaft is designed as a hollow shaft.

[0050] Asynchronous operation, especially continuous asynchronous operation not just for short periods, is often an indication of a fault. Therefore, it can help identify damage to the coupling.

[0051] The advantage provided by this invention is that it eliminates the need for costly, oversized components, particularly sensor couplings, sensor shafts, and sensor bearings.

[0052] For example, the present invention can identify clutches that are damaged or destroyed due to overload.

[0053] This invention is particularly well-suited for servo motors. Servo motors typically have self-supporting sensors. Here, the sensor shaft is connected to the machine shaft via a clutch. If the sensor bearing fails, it becomes sluggish and the sensor coupling bears a heavier load. This can lead to failure. However, this invention offers the advantage of being able to identify this. Attached Figure Description

[0054] The invention will now be described and explained in more detail with reference to the embodiments shown in the accompanying drawings. The drawings show:

[0055] Figure 1 An exploded view of an exemplary servo motor is shown.

[0056] Figure 2 A feasible embodiment of a device for monitoring a coupling connecting a first shaft and a second shaft is shown.

[0057] Figure 3 Another feasible embodiment of a device for monitoring the coupling connecting the first shaft and the second shaft is shown.

[0058] Figure 4 A method is shown. DETAILED DESCRIPTION

[0059] Figure 1 An exploded view of an exemplary servo motor 100 is shown. The servo motor has a sensor 1, a brake 2, a shaft 3, a connecting device 4 and a drive component 5.

[0060] The figure also shows a direction of rotation 6.

[0061] The figure also shows a device 10 for monitoring a coupling of a first shaft to a second shaft. The device 10 is described in more detail in the following figures. The device 10 can be used for monitoring a coupling of a sensor shaft to a machine shaft (as shown in the figure). Furthermore, it is conceivable that the device 10 for monitoring a coupling of a machine shaft is arranged with a load. The device 10 is also suitable for other couplings.

[0062] Figure 2 A possible embodiment of a device 10 for monitoring a coupling of a first shaft to a second shaft is shown.

[0063] The first shaft in the figure is a machine shaft 3. The second shaft in the figure is a sensor shaft 31. The figure also shows that the machine shaft 3 and the sensor shaft 3 are coupled by means of a clutch 7 (also referred to as a coupling).

[0064] The figure also shows an axis of rotation A.

[0065] The device 10 comprises an optical unit 121 with a receiving element which is designed to receive electromagnetic radiation, in particular light. In the figure, this is a photodiode 14. Other receiving elements are also conceivable.

[0066] In the embodiment shown in the figure, the optical unit 121 does not comprise an emitting element.

[0067] The optical unit 121 is arranged in or at the sensor 1 in the figure.

[0068] The device 10 comprises a rod 51. The rod 50 is fastened in the machine shaft 3 which is designed as a hollow shaft by means of a first fastening 50 in the figure.

[0069] The rod 51 is also fastened in the sensor shaft 31 which is designed as a hollow shaft by means of a second fastening 52.

[0070] It is also possible to fasten the rod 51 at another point, for example at the outer circumference of the shaft 3 or the shaft 31.

[0071] The figure shows a front axial end 511 and a rear axial end 512 of the rod 51.

[0072] The lever is advantageously designed so that it can be cut off or broken when the machine axis 3 is running asynchronously relative to the sensor axis 31.

[0073] During operation of the machine shaft 3 and the sensor shaft 31, the first fracture surface of the first part of the rod caused by cutting and / or breaking, particularly the fracture surface on the machine shaft side, and the second fracture surface of the second part of the rod caused by cutting and / or breaking, particularly the fracture surface on the sensor shaft side, advantageously rub against each other, so that radiation, preferably light, can be emitted, especially by frictional light emission.

[0074] The photodiode 14 detects this and can transmit the information, for example, to the control unit of the servo motor (not shown).

[0075] The rod 51 is advantageously made of plastic, such as PTFE.

[0076] The rod 51 can be glued to, for example, a shaft 3 or shaft 31 that is implemented as a hollow shaft, or glued to the outer circumference of a shaft 3 or shaft 31.

[0077] Jet injection molding is also an option to consider.

[0078] Advantageously, the material of rod 51 is transparent, especially transparent plastic.

[0079] Due to the principles of optical operation, transparent materials are advantageous, allowing light signals to be transmitted optimally through the rod.

[0080] If the connection established between the sensor shaft 31 and the machine shaft 3 via the clutch 7 is released, the rod 51 is cut off or broken.

[0081] Therefore, the rod 51 can have a predetermined break point 200.

[0082] The friction of the broken rod 51 or its broken surface can be evaluated by measuring the triboluminescence effect using a photodiode 14.

[0083] The distance between the optical unit 121 and the fastener 50, which are advantageously arranged on the sensor side, is advantageously a few centimeters, for example, from 1 cm to 50 cm.

[0084] However, in the case of very large machines, the distance can also be extended to several meters, such as 1 to 10 meters.

[0085] Figure 3 Another feasible embodiment of the device 10 for monitoring the coupling that connects the first shaft and the second shaft is shown.

[0086] replace Figure 2 The triboluminescence described in the text can also be used to evaluate the changes in the reflectivity of the broken rod 51.

[0087] Here, additional illumination is helpful.

[0088] This is achieved by an optical unit 122 with an emission element in the form of a light emitting diode 17. Other emission elements can also be considered. It can also be considered that the lighting conditions prevailing at the installation location of the device 10 are sufficient for the illumination.

[0089] The figure shows a sensor shaft 31 coupled to the machine shaft 3. The shaft 3 and the shaft 31 are designed as hollow shafts in the figure. The rod 51 is located therein.

[0090] The illumination is achieved on the sensor side and is advantageously reflected at the mirror 16 arranged on the machine shaft side. The brightness is detected by a photodiode 14 arranged on the sensor side.

[0091] The described arrangement of components is preferred. However, it is also possible to arrange the optical unit 121 or the optical unit 122 at the axial end of the machine shaft 3 and to similarly exchange the other components.

[0092] The distance between the optical unit 122 advantageously arranged on the sensor side and the mirror 16 is advantageously a few centimeters, for example 1 cm to 50 cm.

[0093] However, in the case of very large machines, the distance can also extend to several meters, for example 1 to 10 m.

[0094] The invention offers the advantage that a damaged clutch can be identified reliably and in an inexpensive manner.

[0095] Figure 4 A method is shown.

[0096] In an optional method step S1, an emission element emits electromagnetic radiation, in particular light.

[0097] In method step S2, an asynchronous operation of the machine shaft with respect to the sensor shaft occurs, whereby the rod breaks or is severed.

[0098] In method step S3, for Figure 2 In the embodiment of the device described in, the breaking surfaces rub against each other, so that, in particular, the emission of radiation, preferably light, takes place by friction.

[0099] In method step S3, for Figure 3 In the embodiment of the device described in, the reflection properties change as a result of the breaking or severing of the rod and / or as a result of the mutual rubbing of the breaking surfaces. This is because, in this embodiment, the radiation that has already been emitted (see S1) is advantageously reflected by the mirror.

[0100] In method step S4, the radiation that has been emitted or the changed reflection properties are identified by a photodiode.

Claims

1. A device (10) for monitoring a coupling of a first shaft (3) to a second shaft (31), the device having: - an optical unit (121) with a receiving element (14) designed to receive electromagnetic radiation in the form of light, - a failure notification element (51), wherein, the failure notification element (51) being arrangeable on and / or in the first shaft (3) and on and / or in the second shaft (31), - wherein the failure notification element (51) is designed to notify an asynchronous operation of the first shaft (3) relative to the second shaft (31).

2. The apparatus (10) of claim 1, wherein, A front axial end (511) of the failure notification element (51) is fastenable at the first shaft (3), wherein a rear axial end (512) is fastenable at the second shaft (31).

3. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) is designed to be cut off or broken off when the first shaft (3) is operated asynchronously relative to the second shaft (31).

4. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) is designed such that, during operation of the first shaft (3) and the second shaft (31), a first fracture surface of a first part of the failure notification element (51) caused by cutting off and / or breaking off rubs against a second fracture surface of a second part of the failure notification element (51) caused by cutting off and / or breaking off, so that radiation can be emitted by luminescence by friction.

5. The apparatus (10) of claim 4, wherein, Light can be emitted by luminescence by friction.

6. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) has plastic.

7. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) has polytetrafluoroethylene and / or polydimethylsiloxane.

8. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) has a predetermined breaking point (200).

9. The apparatus (10) according to claim 1 or 2, wherein The failure notification element (51) has a reflecting element.

10. The apparatus (10) of claim 9, wherein, The reflecting element is a mirror (16).

11. The device (10) according to claim 1 or 2, having an emitting element (17).

12. The device (10) according to claim 11, the emitting element being designed as a light emitting diode.

13. The apparatus (10) according to claim 1 or 2, wherein, The receiving element (14) is designed as a photodiode.

14. The apparatus (10) according to claim 1 or 2, wherein, The receiving element (14) is designed to receive emitted radiation or reflected radiation.

15. The apparatus (10) according to claim 1 or 2, wherein, The receiving element (14) is designed to detect a change in a reflection characteristic.

16. A coupling (7) having a device (10) according to any one of claims 1 to 15.

17. A rotary electric machine (100) having: - a first shaft (3), - a second shaft (31), wherein, the first shaft (3) and the second shaft (31) being coupled by means of a coupling (7), - a device (10) according to any one of claims 1 to 12.

18. The rotary electric machine (100) of claim 17, wherein, The first shaft (3) and / or the second shaft (31) is designed as a hollow shaft.

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