TORQUE LIMITING COUPLING

Abstract

A torque limiting coupling for a driveline has an input side that is connectable to a power unit and an output side that is connectable to a load. A first sensor is assigned to the input side and a second sensor is assigned to the output side of the torque limiting coupling to measure the rotational speed of the input and output side. At least an additional sensor or detector is assigned to the input and/or output side to enhance the resolution of the rotation measurement.

Claims

1-14. (canceled)

15. A torque limiting coupling for a driveline, comprising: an input side to be connected to a power unit and an output side to be connected to a load; a first sensor assigned to said input side and a second sensor assigned to said output side; at least one of said first and second sensors having an encoder with a plurality of markings; and at least one additional detector assigned to said input side and/or said output side, said at least one additional detector being disposed at a predetermined angle in order to detect pulses with a phase shift.

16. The torque limiting coupling according to claim 15, wherein each of said first and second sensors is a detector with a correspondingly associated encoder.

17. The torque limiting coupling according to claim 15, wherein said encoder is formed with at least 80 markings.

18. The torque limiting coupling according to claim 17, wherein said encoder is formed with at least 150 markings.

19. The torque limiting coupling according to claim 15, which comprises a revolution counter marking for identification of a full turn and/or for determination of an angular position disposed at least at said input and/or said output side and wherein at least one of said first and/or said second sensor comprises a revolution counter marking.

20. The torque limiting coupling according to claim 15, wherein said first or said second sensor is configured to detect at least 5000 signals per second.

21. The torque limiting coupling according to claim 20, wherein said first or said second sensor is configured to detect at least 10,000 signals per second.

22. The torque limiting coupling according to claim 19, wherein said at least one revolution counter marking is integrated into an encoder of at least one of said sensors, the counter marking being an unambiguous irregularity.

23. The torque limiting coupling according to claim 15, wherein at least one of said encoders of said sensors of said input side are disposed in torque proof relationship on a first part of the torque limiting coupling and/or at least one of said encoders of said sensors of said output side are disposed in torque proof relationship on a second part of the torque limiting coupling.

24. The torque limiting coupling according to claim 15, which comprises a connection with a release mechanism for connecting a coupling control unit to the torque limiting coupling for determining overload events of the torque limiting coupling, wherein said release mechanism is configured to be triggered by a coupling control unit.

25. The torque limiting coupling according to claim 24, wherein said release mechanism is a device selected from the group consisting of an hydraulic device, a pneumatic device and an explosive device.

26. The torque limiting coupling according to claim 25, wherein said release mechanism is an electronic device or an electro-mechanic device.

27. The torque limiting coupling according to claim 24, wherein the coupling control unit is assigned to the torque limiting coupling for determining an overload event of the torque limiting coupling, and the coupling control unit comprises an transmitter for sending out data and/or trigger signals.

28. The torque limiting coupling according to claim 24, which further comprises a cooling system, wherein a cooling by said cooling system is taken into account in calculating an allowed overload.

29. A driveline, comprising: a power unit, a load, and a torque limiting coupling according to claim 15 connected between said load and said power unit.

30. The driveline of claim 29, further comprising a load control unit assigned to said load and configured to control said load in dependence of data from said coupling control unit.

31. The driveline of claim 30, wherein said load control unit is configured to control said load in dependence of a slippage value determined by said coupling control unit.

32. A method of operating a torque limiting coupling within a driveline, the method comprising: determining an angle position of an input side of the torque limiting coupling or an angle velocity by detecting a predetermined number of signals for each full turn, thereby detecting signals by a first detector and detecting phase shifted signals by an additional detector; determining an angle position of an output side of the torque limiting coupling or an angle velocity of the output side; defining a slip of the torque limiting coupling by determining a difference of the angle position of the input side and the angle position of the output side or determining a difference between the velocities of the input side and output side at the same time, wherein slip events in a range of few degrees are taken under account; calculating a service interval and/or an predetermined value of overload; and transmitting the calculated information.

33. The method according to claim 32, which comprises: using a coupling control unit to calculate an overload value and, upon determining that a predetermined overload value is exceeded, transmitting information from the coupling control unit to a power control unit and/or to a load control unit, and adjusting one or both of an output of the power unit and/or a load.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the present preferred embodiments together with the accompanying drawings. The scope of this invention is not limited by these embodiments.

[0037] FIG. 1: Driveline comprising a torque limiting coupling and a slip angle measurement

[0038] FIG. 2: Driveline comprising a torque limiting coupling and an enhanced slip angle measurement

[0039] FIG. 3: Toothed wheel usable as impulse generator

[0040] FIG. 4: Impulse generator in form of a readable stripe pattern

DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENTS

[0041] FIG. 1 discloses a driveline 1 comprising torque limiting coupling 3. The driveline 1 comprises a power unit 2 for driving an input shaft 16 of an input side 4 rotationally. The input shaft 16 is connected with a torque limiting coupling 3. By the torque limiting coupling 3 torque is transferrable to an output shaft 18 of an output side 5. The output shaft 18 is connected with a load 6. In this embodiment the torque limiting coupling 3 comprises a first encoder 11. The first encoder 11 is an impulse generator. The encoder is read out by a first detector 12. The signals read out by the first detector are transferred to a coupling control unit 26. In the shown embodiment there is a data line between the first detector 12 and the coupling control unit 26, but a wireless connection is also possible. The first encoder 11 and the first detector 12 are parts of a first sensor 10. The torque limiting coupling 3 comprises a first part torque proof connected to the input shaft 16. For connection of the first part of the torque limiting coupling 3 a flange can be used. Further the torque limiting coupling 3 comprises a second part torque proof connected with the output shaft 18. A second encoder 21 of a second sensor 20 is torque proof connected with the second part of the torque limiting coupling 3. A second detector 22 for reading out the second encoder 21 is in signal connection with the coupling control unit 26. The connection can be wired or wireless. The control unit 26 determines the angle position of the first part of the torque limiting coupling 3 based on the signals of the first sensor 10. Further the coupling control unit determines the angle position of the second part of the torque limiting coupling 3. The angle positions of the first part and the second part of the torque limiting coupling 3 are determined for equal instants of time. For determination of a slippage of the torque limiting coupling 3, the difference of the determined angle positions at an instant of time detected by the first sensor 10 and the second sensor 20 is determined. A determined difference correlates to a slippage within the torque limiting coupling 3. By storing the slipping angles over the time, the slipping events and slippage duration can be analyzed. Small slip events can be determined and long slip events can be determined. In this embodiment small slip events are slip events with an slipping angles up to 5. In dependence of the determined slip events, frequency and duration, trigger signals are sent out. It is possible to determine service intervals under respect of the determined slipping events under respect of the kind of slipping event. Because of the first and second encoder 11, 21 arranged on the torque limiting coupling 3 and the detectors 12, 22 are assigned thereto only the torque limiting coupling is enhanced and the remaining driveline 1 is not affected.

[0042] FIG. 2 discloses a driveline 1. The driveline comprises a power unit. The power unit 2 is connected with a gear 8. The gear is used for transformation of rotational speed and torque. The input shaft 16 on the input side 4 of the torque limiting coupling 3 is connected to the gear 8. So power of the power unit 2 is transferrable over the gear to the input side 4 of the torque limiting coupling 3. The torque limiting coupling 3 comprises an input part 17 torque proof connected with the input shaft 16 and a second part 19 torque proof connected to the output shaft 18. A first encoder 11 is also used as additional encoder on the input side 14 assigned to the input shaft 16. The first encoder is torque proof connected with the first part of the torque limiting coupling 17. It is also possible to arrange the first encoder 11 on the first part of the torque limiting coupling 17 and a separate additional encoder on the input shaft 16 of the input side 14, not shown.

[0043] A first detector 12 assigned to the first encoder 11 is arranged radial to read out the first encoder 11. An additional detector 15 on the input side 14 is arranged parallel to the input shaft 16. So the additional detector 15 is arranged axial to read out the first encoder 11.

[0044] An second encoder 21 of the second sensor 20 is arranged on the output shaft 18. In this embodiment the output shaft 18 has a greater diameter than the input put shaft 16 or the outer diameter of the torque limiting coupling 3. It is possible to arrange the second encoder 21 directly on the outer diameter. The number of impulses per full circle from the input side 4 and the output side 5 can be different. An additional sensor on the output side 23 is assigned to the output shaft 18. In this case the additional sensor on the output side 23 comprises an additional detector 25 and an additional encoder 25. Here it is also possible to use the second encoder 21 as additional encoder on the output side 25. Because the angle position of the input side 4 and the angle position of the output side 5 are determined independent from each other it is possible to use encoders 11, 14, 21, 24 wherein impulses of the encoders are assigned to different angle dimensions. So it is possible to have 80 markings on the input side per full turn and 120 markings on the output side per full turn. The signals of the detectors of one side are phase shifted. By the phase shift the measurement is more precisely. It is also possible to have more than two detectors on one side. For example the encoder comprises 144 markings. So the physical resolution is 2.5. If there are two detectors assigned to that encoder and the detectors are phase shifted with a phase of 90 to each other, it is possible to detect the direction of shaft rotation and the resulting resolution is 4-times the physical resolution. So in this case the resulting resolution is 0.625. The shaft rotation can be determined because of the sequence of the measured signals form the sensors.

[0045] To be able to detect rotational direction one encoder, first 11 or second encoder 21, and two detectors, first detector 12 together with the additional detector of the input side 15 or second detector 22 together with additional detector of the output side 25, at least on one side of the coupling are needed. To measure the signals phase shifted, the encoders and/or the detectors are arranged phase shifted. The resulting signals preferably have an phase shift of 90 . The two detectors can be integrated into a physical unit. Two separate encoders 21, 24, mounted on the same side, can also be used but then they need to be identical with the same amount of trigger points.

[0046] The second encoder 21 and second detector 22 on the output side 5 of the coupling 3 are needed. If the rotational direction of that output side should be detected individually, then two detectors, second 22 and additional detector 25 are needed also on the output side 5.

[0047] If the encoders are symmetrical, meaning the 1 marking and the 0 marking correspond to equal rotational angle, then both the 1-marking and the 0-marking signal can be used as triggers in the coupling control unit 26. The spacing between the 1-marking and the 0-marking is even. This makes the measured resolution twice as fine as the number of positive triggers, 1-markings, of the encoder. Thanks to this, the resolution in the slip angle detection is doubled. The time between the pulses is half as long, meaning the coupling control unit 26, if needed, can take action sooner.

[0048] If the encoder is asymmetrical, uneven spacing between the 1-marking and the 0-marking signals, then only one of the signals, 1-marking or 0-marking, can be used, giving only one signal per period. The benefit of having two detectors per encoder arranged with a 90 phase angle is that the coupling control unit 26 receives twice the number of pulses at twice the frequency compared to only having one sensor per encoder. In case of a symmetrical encoder four trigger signals can be used per encoder period in the coupling control unit 26.

[0049] In some cases not the 1-marking and/or the 0-marking is counted as signal, the transition from 1 to 0 and from 0 to 1. Depending on the type of sensor the detector and/or encoder can be mounted radial or axial to the shaft. Axial to the shaft is to mount it parallel to the shaft. The encoder can be a separate part, like a disc or a tape. The encoder can also be integrated in one of the coupling parts. In the embodiment shown in FIG. 2, the load 6 is powered by the output shaft 18. The coupling control 26 is in signal connection to the detectors 10, 13, 20 and 23. The calculation of the angle position of the first part of the torque limiting coupling 17 and the angle position of the second part 19 of the torque limiting coupling 3 is done by the coupling control unit 26. The coupling control unit 26 comprises at least a transmitter 31. The transmitter is able to send out data to a central control unit, not shown and/or to send out a trigger signal and/or data in respect of the determined slippage of the torque limiting coupling 3 to a control unit 27 of the power unit 2 and/or to a load control unit 29. So it is possible in the case to adjust the power unit 2 and/or the load 6 to reduce the number and/or duration of slippage events of the torque limiting coupling 3.

[0050] In this embodiment the load 6 has an output wherein a disconnector 40 is arranged in an output of the load 6. By the disconnector 40 it is possible to disconnect the driveline. For example if the load 6 is a generator to supply current into an electrical grid, it is possible to disconnect the generator from the grid and therewith the whole driveline from the grid. So in the case of disturbances from the side of the electrical grid, especially micro interruptions, or in the case of disturbances from the driveline itself, it is possible to disconnect the driveline from the electrical grid. Further it is possible to analyze the effect of disturbances from the side of the load or grid on the driveline 1. As a power unit 2 especially a gas turbine or a gas motor can be used. Such drivelines can be used for stabilization of an electrical grid.

[0051] FIG. 3 discloses a toothed wheel 45. This toothed wheel 45 comprises the first encoder 11 in form of teeth 49 arranged in radial direction. Every tooth 49 is read out by a contactless working first detector 12 and additional detector 15. As a contactless working sensor a light sensitive detector or inductive working detectors can be used. Further an inductive quadrature sensor can be used. Every tooth 49 is a 1-marking 51. The distances of the 0-marking 53 and the 1-marking 51 are equal. The additional detector 15 is arranged in respect of the first detector 12 with a phase shift of 90. So the direction of rotation is known by the sequence of the impulses detected by the first detector 12 and the additional detector 15.

[0052] The arrangement of the first, second and additional encoders together with the assigned detectors can be chosen under respect of the available space. To arrange all encoders on the torque limiting coupling has the charm that the input side 4/input shaft 16 and the output side 5/output shaft 18 is not affected. To integrate the revolution counter marking 46 in at least one of the encoders 11, 14, 21, 24 the defined angle position can be determined in relation to the revolution counter marking. If the number of impulses per full revolution is known and the direction of rotation is known, the angle position of the other side can be also determined in respect to this revolution counter marking 46. In some cases a revolution counter marking 46 is assigned to both sides for simplification of the determination of the specific angle position of both sides for an instant of time.

[0053] To realize the counter revolution counter marking by a missing tooth or a missing encoder marking, the revolution counter marking 46 can be realized in an easy way. Because of mass gravity speed changes in such short time intervals are not possible. So by such a missing marking the angle position is uniquely defined.

[0054] FIG. 4 discloses an alternative realization of encoders. There is a first encoder 11 and an additional encoder 14 realized in the form of a stripe. The stripe comprises markings which are read out by detectors, not shown, assigned to the encoder. For example a magnetic or reflective structure can be used as an encoder 11, 14. The stripe of FIG. 4 can be arranged on the outer circumference of one of the sides 4, 5 or parts 17, 19. The encoders 11, 14 comprises a 1-marking 51 and a 0-marking 53, wherein the distances of the 1-marking 51 and the 0-marking 53 are uneven.

[0055] As an indication for a slippage in the torque limiting coupling heating up of the torque limiting coupling will take place. So a temperature sensor arranged in or at the torque limiting coupling can be used for detection of slippage. For a more precise measurement the temperature sensor is arranged in at least one of the friction surfaces. It is possible to trigger disengagement in dependence of the detected temperature. Such a temperature sensor can be used additionally to the determination of the slip angle determined based on the angle position of the input side 4 and the output side 5.

[0056] The determination of fast oscillating slips based on the determined angle position of the input side and the output side is possible. Further the service intervals can be determined based on the slippage of the torque limiting coupling, wherein slippage in both directions influences the service interval and further actions like disengagement.

[0057] Based on the determined slippage and the friction engagement of the friction surfaces of the torque limiting coupling 3 the generation of heat of can be calculated. Especially the heat at the friction surfaces can be calculated.

[0058] It is possible to calculate the allowed slip angle dynamically, for example to take under respect cooling effects or an active cooling. Further an active reduction of the slip is possible by regulation and/or controlling of the power unit 2 and/or the load and/or an active brake. The regulation or controlling can be realized by data connection directly or indirectly with coupling control unit 26. The data and trigger signals can be transferred for example by the use of internet/SMS and further wireless data transfer. By the active control of slippage events a release of the torque limiting coupling or a disconnection of the driveline can be prevented. The active control can be established online with a remote access or local.

[0059] Event detection can be established by determination of slip, over-speed of input side or output side, slip speed and slip direction. The results can be saved for analysis.

[0060] It is possible to adjust stored limiting parameters. The limiting parameter of acceptable slip of the torque limiting coupling can be stored in the coupling control unit.

[0061] Alternative or additional the rotational speed of the input side 4 and the output side 5 can be calculated based on the signals of at least the sensors 10 and 20. Further sensor signals of additional sensors 13 and 23 can be used.

[0062] It is possible to have a central control unit comprising the power control unit, load control unit and the signals of the slip events are also transferred to that central control unit.

[0063] As a torque limiting coupling a coupling can be used including at least one thin-walled sleeve which forms an axially extending defining wall of a substantially annular chamber. The chamber is arranged to be supplied with a pressure medium to elastically deform said sleeve in a radial direction into clamping engagement with a surface on an element which is to be connected to the coupling, the shape and dimension of said surface substantially corresponding to the shape and dimension of a surface on the sleeve remote from said chamber. The chamber has extending therefrom a channel arrangement which is arranged to cooperate with release mechanism 28 which can be activated by relative movement between said surfaces, or by a given torsional deformation thereof, to a state in which pressure medium can flow through said channel arrangement from said chamber to relieve the chamber of pressure acting therein.

REFERENCE LIST

[0064] 1 driveline

[0065] 2 power unit, motor

[0066] 3 safety coupling, torque limiting coupling

[0067] 4 input side

[0068] 5 output side

[0069] 6 load, generator

[0070] 7 connector (grid)

[0071] 8 gear

[0072] 10 first sensor (motor side)

[0073] 11 first encoder

[0074] 12 first detector, contactless detector

[0075] 13 additional sensor input side

[0076] 14 additional encoder input side

[0077] 15 additional detector input side

[0078] 16 input shaft

[0079] 17 1.sup.st part of the torque limiting coupling

[0080] 18 output shaft

[0081] 19 2.sup.nd part of the torque limiting coupling

[0082] 20 second sensor (load side)

[0083] 21 2.sup.nd encoder

[0084] 22 2.sup.nd detector, contactless detector

[0085] 23 additional sensor output side

[0086] 24 additional encoder output side

[0087] 25 additional detector output side

[0088] 26 coupling control unit

[0089] 27 power control unit

[0090] 28 release mechanism

[0091] 29 load control unit

[0092] 30 wireless data connection

[0093] 31 transmitter

[0094] 40 disconnector

[0095] 45 toothed wheel

[0096] 46 revolution counter marking

[0097] 49 tooth, marking

[0098] 50 cut out, breakthrough

[0099] 51 1-marking

[0100] 53 0-marking