Metal bellows coupling

Abstract

In order to overcome disadvantages and inadequacies of a metal bellows coupling of the type in question, at least two compensation elements (20) disposed opposite one another, at least one cylindrical hollow element (30) disposed between the compensation elements (20), in particular in the manner of at least one tube (30a) or in particular in the manner of at least one flange (30b), and at least one sensor device or sensor assembly (40) disposed within the hollow element (30) are proposed.

Description

[0001] METAL BELLOWS COUPLING

[0002] Technical area

[0003] The present invention relates to the technical field of metal bellows couplings.

[0004] State of the art

[0005] Metal bellows couplings (see the prior art: DE 40 31 486 A1, or also Fig. 1A, Fig. 1B, Fig. 1C) are used, for example, for power transmission in drive trains. Power is composed of the operating speed and the operating torque.

[0006] Furthermore, metal bellows couplings can be used to connect two hubs or shafts that are not exactly aligned, i.e., to compensate for misalignment from one hub or shaft to another, which is achieved, for example, by bellows couplings. Metal bellows couplings are particularly suitable for direct drives.

[0007] A typical metal bellows is the core of a metal bellows coupling and compensates for lateral, axial, and / or angular hub or shaft misalignments with low restoring forces. Backlash-free, torsionally rigid metal bellows couplings guarantee precise positioning of the drive train, can ensure torque transmissions from 2 Nm to 10,000 Nm, and can be used in highly dynamic applications with up to 120,000 revolutions per minute.

[0008] To fully utilize their technical properties and compensate for hub or shaft misalignments without transmission errors, precise assembly of the metal bellows couplings is crucial. Factors such as operational reliability, acceleration torque, and resonance frequency are important when dimensioning.

[0009] The integration of sensors for measuring physical quantities, such as torque, is not possible in conventional metal bellows couplings. While attachments can be glued, welded, or pressed onto the metal bellows, this is sometimes considered complex and costly.

[0010] Description of the present invention: task, solution, advantages

[0011] Based on the disadvantages and deficiencies outlined above, and taking into account the prior art outlined above, the present invention seeks to further develop a metal bellows coupling of the type mentioned above in such a way that the disadvantages and deficiencies are overcome. This object is achieved according to the invention in a metal bellows coupling of this type as follows:

[0012] The bellows corrugation(s) is / are placed as a respective compensating element, in particular as a respective offset compensating element, at a greater distance from one another so that a cylindrical hollow body, in particular in the manner of at least one pipe or in particular in the manner of at least one flange, is formed therebetween.

[0013] One, two or more bellows corrugations can be used as compensating elements on each side of the metal bellows coupling.

[0014] Strain gauges can be applied to the outer surface of the (hollow) cylinder. Through one or more holes in this surface, the strain gauge cables can be routed inward to at least one sensor device or sensor assembly located within the hollow body.

[0015] Alternatively, the strain gauges can also be applied to the inside of the shell surface and connected directly to at least one sensor device or sensor assembly arranged within the hollow body.

[0016] The sensor metal bellows coupling can be designed as an inductive variant with a wire winding on the outer surface of the cylindrical hollow body and with a pick-up (separate component) for the power supply of the electronics, or as a battery variant in addition to the induction or without induction, or with an energy converter or energy harvester based on an eccentric mass with a generator with or without a battery.

[0017] Within the scope of the disclosure relating to the present invention, at least one capacitive element, in particular at least one capacitor, can be used in combination with an energy converter or energy harvester and / or with induction instead of the at least one battery.

[0018] This has the advantage that a battery with a comparatively high mass and thus mass inertia can be replaced by at least one significantly lighter capacitive element, in particular by at least one significantly lighter capacitor.

[0019] This also has a positive effect in the event of imbalance(s) occurring or being present, in that the sensor technology can be supplied with energy even at high speeds when using a capacitive element or capacitor, whether in combination with an energy converter or energy harvester and / or with induction, which is not easily possible when using one (or more) batteries – the speed-limiting factor. Furthermore, capacitive elements or capacitors, unlike lithium-polymer batteries, for example, are not classified as hazardous goods, which simplifies shipping and trade with regard to the present invention.

[0020] A special feature of the present invention, in particular in comparison to the prior art, is that each of the compensation elements, in particular each of the offset compensation elements, for example in the form of a respective metal bellows or in the form of a respective lamination pack, can itself serve as a base body for the strain gauges and for holding the sensor device or sensor assembly.

[0021] This eliminates the need for special solutions such as aluminum or steel pipes, flanges or other replacement bodies that are conventionally used between two compensation elements, such as two bellows and an aluminum pipe in the middle.

[0022] As a result, the sensor-Z metal bellows coupling according to the present invention is very compact, has a comparatively low mass, thus a comparatively low mass inertia and fewer interfaces between the components.

[0023] According to the present invention, a specific coupling product is enhanced by sensor technology arranged in a hollow cylindrical housing. According to the invention, this specific coupling product is a metal bellows coupling, i.e., a coupling with offset-compensating elements, the so-called bellows corrugations. In combination with the sensor technology arranged in the cylindrical housing, the sensor coupling according to the present invention results.

[0024] Such a particularly high-precision metal bellows coupling can be characterized according to the present invention in particular by the fact that the electronics / sensor technology, in particular the sensor device or sensor assembly, can be provided in at least one compensating element, in particular in at least one offset compensating element, for example in at least one bellows with an elastic element or in at least one bellows corrugation, whereby one or more bellows corrugations are possible per side of the metal bellows coupling as a compensating element. This provides particularly effective and reliable protection for the typically sensitive sensor device or sensor assembly, in particular the sensor electronics, against external influences.

[0025] Such a particularly high-precision metal bellows coupling can be used, especially as a sensor coupling, wherever positioning accuracy is required, for example in medical technology, test benches, wind turbines, or in highly dynamic servo axes, such as those used in machine tools, woodworking machines, packaging machines, and the like. Brief description of the drawings

[0026] As already discussed above, there are various possibilities for advantageously embodying and developing the teachings of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1. On the other hand, further embodiments, features, and advantages of the present invention are explained in more detail below, inter alia, with reference to the exemplary embodiments illustrated by Figs. 2A to 5D.

[0027] It shows:

[0028] Fig. 1A shows a longitudinal section of a metal bellows coupling from the prior art with a metal bellows arranged centrally, namely between the two hubs, consisting of four bellows corrugations;

[0029] Fig. 1 B shows a perspective view of the metal bellows coupling from Fig. 1A;

[0030] Fig. 1C shows a perspective view of various metal bellows couplings from the prior art, each with a different hub connection;

[0031] Fig. 2A shows a longitudinal section through a first embodiment of a metal bellows coupling according to the present invention;

[0032] Fig. 2B shows a perspective view of the metal bellows coupling from Fig. 2A;

[0033] Fig. 3 shows a perspective view of a second embodiment of a metal bellows coupling according to the present invention;

[0034] Fig. 4 shows a perspective view of a third embodiment of a metal bellows coupling according to the present invention;

[0035] Fig. 5A shows a longitudinal section through a fourth embodiment of a metal bellows coupling according to the present invention;

[0036] Fig. 5B shows a perspective view of the metal bellows coupling from Fig. 5A with associated pick-up;

[0037] Fig. 5C shows a perspective view of an embodiment of a modular energy converter or energy harvester that can be associated with the metal bellows coupling of Fig. 5A or Fig. 5B; and

[0038] Fig. 5D shows a perspective view of an embodiment of an eccentric mass element associated with the energy converter or energy harvester from Fig. 5C with several modular (metal) plates for the purpose of variable processing of the mass.

[0039] Identical, similar, or identical configurations, elements, and / or features are provided with the same reference numerals in Figs. 1A to 5D; a repeated description of these configurations, elements, and / or features is omitted. Figs. 1A to 5D are not necessarily to scale; any dimensioning and / or sizing information in Figs. 1A to 5D is purely exemplary.

[0040] Preferred embodiment of the present invention; best mode for carrying out the present invention

[0041] In Fig. 2A to Fig. 5D various embodiments of a metal bellows coupling 102, 104, 106, 108 according to the present invention are shown, namely

[0042] - a first embodiment of a metal bellows coupling 102 in Fig. 2A and Fig. 2B,

[0043] - a second embodiment of a metal bellows coupling 104 in Fig. 3,

[0044] - a third embodiment of a metal bellows coupling 106 in Fig. 4 and

[0045] - a fourth embodiment of a metal bellows coupling 108 in Fig. 5A to Fig. 5D.

[0046] Each of the metal bellows couplings 102, 104, 106, 108 has two compensating elements 20 arranged opposite one another with one or more bellows corrugations, one between the compensating elements 20, for example according to the type

[0047] - a pipe 30a (cf. second embodiment of a metal bellows coupling 104 according to Fig. 3) or

[0048] - a cylindrical hollow body 30 arranged on a flange 30b (cf. third embodiment of a metal bellows coupling 106 according to Fig. 4) and a sensor device or sensor assembly 40 with associated sensor electronics arranged within the hollow body 30, for example integrated in the tube 30a (cf. Fig. 3) or in the flange 30b (cf. Fig. 4).

[0049] The first embodiment of the metal bellows coupling 102 according to Fig. 2A and Fig. 2B has a cylindrical hollow body 30, the internal sensor device or sensor assembly 40, in particular (sensor) electronics, arranged within the hollow body 30, is omitted in Fig. 2A for reasons of clarity of the illustration.

[0050] The sensor device or sensor assembly 40 can be attached to or in the hollow body 30 (reference numeral 42 in Fig. 5A), for example by elastically deformed O-rings, in particular glued or pressed.

[0051] The sensor device or sensor assembly 40 can be assigned a radio antenna, in particular based on Bluetooth®, for the wireless or wireless transmission of sensor data determined by the sensor device or sensor assembly 40.

[0052] The sensor device or sensor assembly 40 has strain gauges (SGs) which are arranged on the outside of the lateral surface of the hollow body 30 and are covered and thus protected by a cover 34 (cf. Fig. 5A), for example by means of a housing or by means of a shrink tube.

[0053] The outer surface of the hollow body 30 has a bore 32, by means of which cables of the strain gauge (DMS), covered and thus protected by the cover 34, can be guided into the interior of the hollow body 30.

[0054] Alternatively, the strain gauges (SGs) can be arranged on the inside of the lateral surface of the hollow body 30, for example, integrated in the tube 30a (see Fig. 3) or in the flange 30b (see Fig. 4).

[0055] On the outside of the outer surface of the hollow body 30, an inductively acting wire winding 44 is provided, which is covered and thus protected by the cover 34, and at least one pick-up 46 is provided as a separate component.

[0056] On and / or within the lateral surface of the hollow body 30, an energy converter or energy harvester 50 is provided for converting mechanical energy into electrical energy, wherein the mechanical energy is provided by a relative rotational movement of the energy converter 50 relative to a rotational axis or hub or shaft of the energy converter 50 and the rotational axis or hub or shaft of the energy converter 50 can be held in position by gravity, in particular by at least one eccentric mass element 54, for example in the form of a plate 54m or several mutually associated plates 54m (cf. Fig. 5C and Fig. 5D).

[0057] The energy converter or Energy Harvester 50 can

[0058] - as an excitation device or generator, in particular as a brushless or slip-ring-less excitation device and / or as a synchronous generator, and / or

[0059] - be designed in a modular manner, in particular as an independent or separate module.

[0060] A storage element, in particular a battery or an accumulator element and / or a capacitive element or a capacitor, for storing electrical energy, in particular for storing an excess portion of the electrical energy, can be provided on and / or within the lateral surface of the hollow body 30.

[0061] As can be seen from the illustration of the respective embodiments according to Fig. 5C and Fig. 5D, the energy converter or energy harvester 50 can also be designed modularly or as a standalone or separate module, i.e., neither integrated nor, in particular, as a fully integrated solution. With such a modular design, only one sensor body design is required (instead of two parallel designs), so that higher production volumes lead to lower costs.

[0062] Should a particular type of excitation device or generator no longer be available, or should a different excitation device or generator be required, the eccentric mass 54 and the electronics 56 can be adapted to the new excitation device or generator. This provides the necessary flexibility to serve a wide range of applications.

[0063] Therefore, if the excitation device or generator needs to be replaced, for example because it is no longer available on the market, only the energy converter or energy harvesting module 50 needs to be adapted; however, series production of the sensor module can remain untouched.

[0064] With a modular design of the energy converter or energy harvester 50, the design of its electronics 56 takes into account two significant technical issues, which, if ignored, would transform the energy converter or energy harvester 50 into an imbalance generator. Such an imbalance must not occur under any circumstances, as imbalances in drive trains can lead to serious damage:

[0065] Such an unbalance generator can occur as a result of resonances, i.e. tests in a speed range of 0 to 3,000 revolutions per minute have shown that resonance effects can lead to the eccentric mass overturning in a certain speed range in the worst case scenario and thus becoming an unbalance generator.

[0066] In this context, the worst case scenario means that the eccentric mass remains in the critical speed range for a longer period of time, so that the eccentric mass has enough time to oscillate.

[0067] Through the targeted selection of electronic components of the energy converter or energy harvester 50 and a corresponding circuit board layout of the electronics 56, this effect can be significantly dampened for the purpose of speed protection, so that resonance no longer represents a problem under operating conditions.

[0068] Furthermore, the circuit board layout of the electronics 56 of the energy converter or energy harvester 50 takes into account that the eccentric mass 54 does not roll over outside of the resonance effect. The challenge here is to control the power output in such a way that the required power can be provided, while excess power is dissipated in a controlled manner; otherwise, the resistance from the magnetic field could become so strong that the rotor is pulled along with the eccentric mass, rolls over, and thus becomes an imbalance generator during normal operation.

[0069] If the output power of the energy harvesting electronics 56 is limited to a certain value, for example to approximately 50 milliwatts, it can be avoided that the eccentric mass or the eccentric mass element 54 on the energy converter 50, in particular on the generator, is deflected more and more at higher speeds and ultimately rotates with the shaft 52.

[0070] By designing the electronics 56 in this way, namely by limiting the output power of the electronics 56 assigned to the energy converter or energy harvester 50, the two problem cases already mentioned above are additionally controlled:

[0071] On the one hand, resonance in the electrical circuit can lead to a flashover of the eccentric mass element 54. In the range above a certain or defined speed, which leads to the activation of the output current limitation of the energy converter or energy harvester 50, an oscillation behavior of the eccentric mass element 54 can occur.

[0072] To control this behavior, the smoothing capacitance provided by one or more smoothing capacitors after the rectifier can be dimensioned sufficiently large.

[0073] Second, it is important to reliably prevent the eccentric mass element 54 from rolling over even during normal operation. When the system is starting up or at low speeds, the generator current is usually significantly higher than at high speeds.

[0074] This is due to the generator's low output voltage in this range. A "soft start" gradually increases the generator current through the electronics 56. This prevents premature rotation of the eccentric mass element 54 with the shaft 52.

[0075] In the modular embodiment (see Fig. 5C and Fig. 5D), the eccentric mass element 54 is designed modularly, namely for the purpose of variable mass processing by means of several mutually associated metal plates 54m. Such a modular design allows the weight of the eccentric mass 54 to be adjusted to the power output of the energy converter or energy harvester 50 depending on its application.

[0076] This serves to keep the load on the rolling bearings of the excitation device or generator and the overall weight of the energy converter or Energy Harvester 50 as low as possible and thus maximize its service life.

[0077] Alternatively, especially in series production, the eccentric mass 54 can be made of solid material.

[0078] The compensation element, in particular offset compensation element 20, is designed as a base body for the strain gauges (DMS) and for holding the sensor device or sensor assembly.

[0079] The metal bellows coupling 102, 104, 106, 108 according to Fig. 2A to Fig. 5D is characterized in particular by the fact that the sensor system / electronics 52 is provided in a complete bellows with an elastic element, wherein one or more bellows wave(s) per side are possible as compensation element 20, for example

[0080] - one bellows wave per side in the first embodiment of the metal bellows coupling 102 in Fig. 2A and Fig. 2B,

[0081] - one metal bellows 20a each with four bellows corrugations per side in the second embodiment of the metal bellows coupling 104 in Fig. 3,

[0082] - one plate pack 20b per side in the third embodiment of the metal bellows coupling 106 in Fig. 4 and

[0083] - two bellows waves per side in the fourth embodiment of the metal bellows coupling 108 in Fig. 5A and Fig. 5B.

[0084] Such a particularly high-precision metal bellows coupling 102, 104, 106, 108 according to Fig. 2A to Fig. 5D can be used, particularly as a sensor coupling, wherever positioning accuracy is required, for example in medical technology, in test benches, in wind turbines or in highly dynamic servo axes, such as in machine tools, woodworking machines, packaging machines and the like.

[0085] List of reference symbols

[0086] 100 Metal bellows coupling (= state of the art according to Fig. 1A and Fig. 1B)

[0087] 100' various metal bellows couplings (= state of the art according to Fig. 1C)

[0088] 102 Metal bellows coupling (= first embodiment according to Fig. 2A)

[0089] 104 Metal bellows coupling (= second embodiment according to Fig. 3)

[0090] 106 Metal bellows coupling (= third embodiment according to Fig. 4)

[0091] 108 Metal bellows coupling (= fourth embodiment according to Fig. 5)

[0092] 10 Hub

[0093] 12 Metal bellows (= state of the art according to Fig. 1A and Fig. 1B)

[0094] 20 Compensation element, in particular offset compensation element, for example in the form of at least one bellows corrugation a Compensation element, in particular offset compensation element, in the form of a metal bellows b Compensation element, in particular offset compensation element, in the form of a plate pack cylindrical hollow body a cylindrical hollow body in the form of a tube b cylindrical hollow body in the form of a flange bore of the cylindrical hollow body 30 Cover

[0095] Sensor device or sensor assembly

[0096] Mounting the sensor device or sensor assembly 40

[0097] Wire winding

[0098] Pick up

[0099] Energy converter or energy harvester

[0100] Rotation axis or hub or shaft eccentric mass element m plate, in particular metal plate, of the eccentric mass element 14

[0101] Electronics, in particular electronic components, of the energy converter or energy harvester 50

[0102] Housing, in particular cylindrical hollow body

Claims

Claims 1. Metal bellows coupling (102; 104; 106; 108) with at least two compensating elements (20) arranged opposite one another, with at least one cylindrical hollow body (30) arranged between the compensating elements (20), in particular in the manner of at least one pipe (30a) or in particular in the manner of at least one flange (30b), and with at least one sensor device or sensor assembly (40) arranged within the hollow body (30).

2. Metal bellows coupling according to claim 1, wherein on each side of the metal bellows coupling (102; 104; 106; 108) as the compensating element (20), one, two or more bellows corrugations are provided, in particular in the form of an offset compensating element, for example in the form of a metal bellows (20a) or in the form of a plate pack (20b).

3. Metal bellows coupling according to claim 1 or 2, wherein the sensor device or Sensor assembly (40) is assigned at least one sensor electronics.

4. Metal bellows coupling according to at least one of claims 1 to 3, wherein the Sensor device or sensor assembly (40) is assigned at least one radio antenna, in particular based on Bluetooth®, provided for the wire-free or wireless transmission of sensor data determined by the sensor device or sensor assembly (40).

5. Metal bellows coupling according to at least one of claims 1 to 4, wherein the sensor device or sensor assembly (40) has at least one strain gauge (DMS) which is arranged on the outside of the hollow body (30), in particular the lateral surface of the hollow body (30).

6. Metal bellows coupling according to claim 5, wherein the outer surface of the hollow body (30) has at least one bore (32) by means of which at least one cable of the at least one strain gauge (DMS) can be guided into the interior of the hollow body (30).

7. Metal bellows coupling according to at least one of claims 1 to 4, wherein the sensor device or sensor assembly (40) has at least one strain gauge (DMS) which is arranged on the inside of the hollow body (30), in particular the outer surface of the hollow body (30).

8. Metal bellows coupling according to at least one of claims 1 to 7, wherein at least one inductively acting wire winding (44) is provided on the outside of the hollow body (30), in particular the outer surface of the hollow body (30), and / or at least one pick-up (46) is provided as a separate component.

9. Metal bellows coupling according to at least one of claims 1 to 8, wherein at least one energy converter (50) for converting mechanical energy into electrical energy is provided on and / or within the outer surface of the hollow body (30).

10. Metal bellows coupling according to claim 9, wherein the mechanical energy is provided by a relative rotational movement of the energy converter (50) relative to a rotational axis or hub or shaft (52) of the energy converter (50).

11. Metal bellows coupling according to claim 10, wherein the rotational axis or hub or shaft (52) of the energy converter (50) is held in position by gravity, in particular by at least one eccentric mass element (54), for example in the form of a plate (54m) or several mutually associated plates (54m).

12. Metal bellows coupling according to at least one of claims 9 to 11, wherein the energy converter (50) is designed as an excitation device or generator, in particular as a brushless or slip-ring-less excitation device and / or as a synchronous generator, and / or modular, in particular as an independent or separate module.

13. Metal bellows coupling according to at least one of claims 1 to 12, wherein at least one storage element, in particular at least one battery or at least one accumulator element and / or at least one capacitive element or at least one capacitor, for storing electrical energy, in particular for storing an excess portion of the electrical energy, is provided on and / or within the outer surface of the hollow body (30).

14. Metal bellows coupling according to at least one of claims 1 to 13, wherein the compensating element (20) is designed as a base body for the at least one strain gauge (DMS) and / or for holding the sensor device or sensor assembly (40).

15. Use of at least one metal bellows coupling (102; 104; 106; 108) according to at least one of claims 1 to 14 in medical technology, in test benches, in wind turbines or in highly dynamic servo axes, in particular of machine tools, woodworking machines, packaging machines and the like.

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