Universal joint with oil bath clutch torque limiter and drive shaft comprising said joint

Abstract

A universal joint (1) comprises a pair of yokes (7A, 7B) and a spider (7C) providing a connection between the yokes (7a, 7B). A hub (21) is associated with and coaxial with the first yoke (7A). A torque limiter (25) is interposed between the hub (21) and the first yoke (7A). The torque limiter (25) includes clutches (41, 45) housed in an oil bath chamber (30).

Description

Technical Field

[0001] The present invention relates to improvements in universal joints and drive shafts including one or more universal joints. Background Art

[0002] Universal joints are used in a variety of applications to transfer motion between two shafts or shaft sections that may be tilted relative to each other. Universal joints are commonly used in agricultural machinery to transfer motion from a tractor or other motor unit to a driven machine. Universal joints are often combined with a drive shaft. The drive shaft may comprise part of a telescopic shaft comprising two tubular members that are inserted into one another for telescopic sliding movement, with two opposing universal joints associated at each end.

[0003] Typically, to prevent damage to transmission components, machines connected via a universal shaft drive, or machines typically incorporating at least one universal joint, the universal joint includes a torque limiter that interrupts the transmission of the driving torque when the transmitted torque exceeds a certain limit, for example due to a mechanical blockage in the driven machine. Some drive shafts include universal joints with clutch torque limiters. Known joints of this type include a first yoke and a second yoke connected by a cross shaft. The joint further includes a first hub coaxial with and torsionally coupled to the first yoke, and a second hub coaxial with and torsionally coupled to the second yoke. The clutch torque limiter is disposed between one of the first and second hubs and the corresponding yoke and typically includes a clutch disc torsionally constrained to the hub and a clutch disc torsionally constrained to the yoke. When torque exceeds a predetermined limit, the disc attached to the hub slips relative to the disc attached to the yoke, interrupting torque transmission. Due to mutual friction, the clutch discs wear rapidly. Wear of the clutch discs causes them to become thinner, reducing the torque limit at which the clutch discs can slip relative to each other. This is because wear reduces the interaction force of the friction discs pushing against each other, thereby reducing the friction that transmits torque between the hub and fork. Summary of the Invention

[0004] The embodiments disclosed herein provide a universal joint that overcomes or mitigates the disadvantages of prior art universal joints with clutch torque limiters. According to another aspect, a drive shaft is disclosed that includes at least one universal joint with a clutch torque limiter.

[0005] In summary, according to the invention, a universal joint with a clutch torque limiter is provided, in particular a universal joint with a disk clutch, wherein the disk clutch is located in an oil bath.

[0006] In this way, the wear of the clutch during slipping is significantly reduced, thereby extending the service life of the universal joint and reducing the change in the clutch intervention torque limit due to wear.

[0007] According to one embodiment, a universal joint is provided, comprising a first yoke and a second yoke connected to each other via a cross shaft. The universal joint further comprises a hub coaxial with the first yoke and a torque limiter positioned between the hub and the first yoke. The torque limiter comprises a clutch housed in an oil bath.

[0008] Advantageous embodiments of the universal joint according to the invention are described hereinafter with reference to the accompanying drawings and set forth in the appended claims.

[0009] In some embodiments, an oil-bath clutch can be sensorized. For example, it can include at least one temperature sensor adapted to detect the temperature of the oil bath or a component of the universal joint, which in turn depends on the temperature of the oil. This allows for the detection of abnormal oil overheating conditions, such as those caused by a clutch slipping state lasting too long. Every time the clutch slips, frictional heat is generated. If the clutch slips for too long, or if the speed difference between the yoke and hub is too large, the heat generated by friction can cause the oil to overheat, and this abnormal condition can be detected and reported via the temperature sensor.

[0010] In some embodiments, a vibration sensor or speed sensor may also be provided, configured to detect the presence of relative slippage between the hub and yoke (i.e., a clutch slip state). The control unit can measure the time during which the clutch slips and, for example, report if the clutch slip state persists for an excessively long time. Indeed, if the torque limiter clutch slips, the vibration state of the universal joint 7 changes. Therefore, the signal from the vibration sensor allows detection of whether and when the torque limiter intervenes due to clutch slippage.

[0011] As described below, one or more sensors can be carried by the yoke and therefore participate in the rotational movement of the joint. In other embodiments, one or both sensors can be fixed, i.e. dormant, wherein fixed or dormant means that they do not participate in the rotational movement of the joint. For example, the sensor(s) can be mounted on a protective cover that at least partially surrounds the joint, or on a protective cover holder. This simplifies the power supply and data collection of the sensor(s). The temperature measurement can be carried out contactlessly, for example with the aid of an infrared system, while the slip state can be detected by measuring the rotational speed of the hub and yoke (the clutch is placed between the hub and the yoke) using a special sensor suitable for measuring the relative speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention may be better understood through the following description and accompanying drawings, which illustrate exemplary and non-limiting embodiments of the present invention. More specifically, the accompanying drawings show:

[0013] Figure 1 is a side view of a cardan shaft, showing a partial section of a protection device for rotating parts of said shaft;

[0014] Figure 2 for Figure 1 a cross-section of a yoke of one of the universal joints of the shaft along a plane containing the axis of the universal joint, the yoke containing a torque limiting clutch;

[0015] Figure 3 for Figure 2 Axonometric drawing of the yoke in;

[0016] Figure 4 is a schematic external view of a sensorized joint with a sensor integrated with the yoke;

[0017] Figure 5 For Figure 4 Functional diagram of sensors and control units associated with the sensorized connector;

[0018] Figure 6 is an external partial cross-sectional view of a system including a sensored connector with a resting boot and a sensor associated with the resting boot; and

[0019] Figure 7 For Figure 6 Functional diagram of the sensors and control units associated with the sensorized system in Figure 1. DETAILED DESCRIPTION

[0020] Figure 1 A universal joint is shown, generally designated by the reference numeral 1. The universal joint 1 comprises a telescopic shaft 3 having a first end and a second end. AA denotes the axis of rotation of the telescopic shaft 3. The telescopic shaft 3 comprises two telescopic elements 3A, 3B, which slide into one another to allow extension and contraction of the telescopic shaft 3 and, therefore, of the universal joint 1.

[0021] A first universal joint 5 is associated with a first end of the telescopic shaft 3, and a second universal joint 7 is associated with a second end of the telescopic shaft 3. Reference numeral 9 denotes a telescopically extendable protection device surrounding the telescopic shaft 3, while reference numerals 11 and 13 denote end protection devices that at least partially protect the universal joints 5 and 7.

[0022] One of the two universal joints 5 and 7 can be manufactured in a conventional manner and without a torque limiter. In the illustrated example, the first universal joint 5 has no torque limiter, while the universal joint 7 is provided with a torque limiter which will be described in detail below.

[0023] Reference numerals 5A and 5B denote two yokes of a universal joint 5, which are coupled together by a cross shaft 5C. Reference numeral 5D denotes a connecting hub connected to a driving machine or a driven machine, for example, to a power take-off of a tractor not shown.

[0024] The universal joint 7 comprises a yoke 7A rotatably, i.e. torsionally, constrained to the hub 21, and a yoke 7B integral with the hub 23. The hub 23 is mechanically constrained to the tubular element 3B of the telescopic shaft 3. Reference numeral 7C denotes a cross shaft connecting the yokes 7A and 7B to each other.

[0025] The yoke 7A is provided with a clutch torque limiter, generally indicated by the reference numeral 25, more particularly a torque limiter comprising a disc clutch, which limits the torque transmitted by the yoke 7A to the hub 21. In particular, the torque limiter 25 is calibrated so that when the torque between the yoke 7A and the hub 21 exceeds a threshold value, the clutch begins to slip, thereby preventing power transmission, while when the torque is below the threshold value, the hub 21 is rotationally, that is to say torsionally, constrained to the yoke 7A and rotates together with it.

[0026] exist Figure 2 and Figure 3 The structures of the yoke 7A, the hub 21 and the corresponding clutch torque limiter 25 are exemplified in detail in FIG.

[0027] The yoke 7A comprises two arms 27 , each of which engages a coaxial pin of the cross shaft 7C. In the embodiment illustrated, the two arms 27 are integral with a closing flange 29 of an oil bath 30 , which is delimited by the closing flange 29 and a closing body 31 .

[0028] In some embodiments, the closure body 31 includes a bottom wall 31.1 and a peripheral wall 31.2, the peripheral wall surrounding the axis BB of the yoke 7, which coincides with the axis of the hub 21. In some embodiments, the bottom wall 31.1 is perforated to allow the hub 21 to pass through. Reference numeral 35 denotes a seal surrounding the hub 21 to prevent oil from leaking from the oil bath 30. A gasket (e.g., an O-ring), shown at 36, can be interposed between the closure flange 29 and the closure body 31.

[0029] In some embodiments, the closing body 31 is connected to the closing flange 29 by screws 37, which can pass through through holes formed in the closing flange and engage in threaded blind holes in the closing body 31. Reference numeral 37 denotes a screw connecting the closing flange 29 to the closing body 31. A sealing washer 39 can be inserted between the head of each screw 37 and the closing flange.

[0030] The clutch members of the clutch torque limiter 25 are housed within the oil bath 30. In the illustrated embodiment, the clutch members include a series of first clutch plates 41 torsionally constrained to the hub 21. In the illustrated embodiment, the first clutch plates 41 are torsionally constrained to the hub 21 via spline profiles 43. Between each pair of adjacent first clutch plates 41, a second clutch plate 45 from a series of second clutch plates is interposed, the second clutch plates being torsionally constrained to the yoke 7. The second clutch plates 45 can be coupled to the yoke via screws 37. To this end, each second clutch plate 45 can have a series of holes parallel to the axis BB, through each of which a corresponding screw 37 extends.

[0031] The resilient member 47 presses the first clutch disc 41 and the second clutch disc 45 against each other. In the illustrated embodiment, the resilient member 47 comprises a disc spring that is coaxial with the hub 21 and the discs 41 , 45 .

[0032] The elastic member 47 is calibrated so that torque is transmitted between the yoke 7A and the hub 21 via the static friction force generated between the first clutch plate 41 and the second clutch plate 45 until the transmitted torque reaches a threshold value, at which time the torque limiter 25 intervenes by causing the first clutch plate 41 to slide relative to the second clutch plate 45. The threshold value of the transmittable torque can be determined by selecting a suitable size (thickness) and a suitable number of clutch plates and by selecting a suitable disc spring 47.

[0033] The first clutch disc 41 and the second clutch disc 45 are immersed in an oil bath contained in the oil bath 30 so that the mutual sliding between the first clutch disc 41 and the second clutch disc 45 results in limited and almost negligible wear of the clutch discs. This allows the total thickness of the clutch discs 41, 45 to remain approximately constant even in the event of long-term intervention by the torque limiter 25. This allows the force exerted by the disc springs 47 to remain constant and thus maintain the calibration of the torque limiter 25.

[0034] In some embodiments, as illustrated in the accompanying drawings, in order to facilitate the rotation of the hub 21 in the oil bath 30 when the torque limiter clutch 25 slips, it is advantageous to provide a bearing arrangement between the hub 21 and the components that define the oil bath 21 (particularly the closing body 31 and the closing flange 29).

[0035] In some embodiments, the bearing arrangement comprises a first bearing 51 coaxial with the axis BB and interposed between the enclosure 31 and the hub 21. In the embodiment illustrated, the first bearing 51 is a ball bearing, but the possibility of using other types of bearings is not excluded, including rolling bearings and (in a less advantageous form) sliding bearings.

[0036] In the exemplary embodiment, the first bearing 51 is housed in a seat 53 of the closing body 31 between the oil bath 31 and the seal 35 .

[0037] In an advantageous embodiment, the hub 21 is supported relative to the yoke 7A via a second bearing 55 coaxial with the axis BB. In the illustrated embodiment, the second bearing 55 is a ball bearing, but the possibility of using other types of rolling bearings or even plane bearings is not excluded.

[0038] In the illustrated embodiment, the second bearing 55 is housed in a bore 57 of the hub 21. Specifically, in the illustrated embodiment, the bore 57 is a through-hole to facilitate machining of the hub 21 and reduce its weight. An internal spline profile 59 is also formed in the through-hole 57 to couple the hub 21 to a power take-off, such as that of a driven machine. Reference numeral 61 denotes a transverse pin for interconnecting the internal spline profile 59 with an external spline profile of a power take-off (not shown).

[0039] In the embodiment illustrated, the inner ring of the bearing 55 is connected to a pin 63 integral with the flange 29 , for example made integral with the flange 29 and projecting from the flange 21 on the opposite side relative to the arm 27 .

[0040] In order to avoid leakage of oil from the oil bath 30 towards the through-hole 57 and thus outside the universal joint 7 , in an advantageous embodiment a plug 65 is arranged inside the through-hole 57 , said plug being placed between the second bearing 55 and the internal spline profile 59 .

[0041] In an advantageous embodiment, the clutch torque limiter 25 can be provided with a temperature sensor adapted to detect the temperature of the oil within the oil bath 30. For further details, see the following description. The temperature sensor can be associated with a control system that limits clutch slippage when the oil temperature rises above a first threshold value to prevent damage to clutch components. For example, when the detected temperature reaches the threshold value, a signal generated by the sensor and detected by the central unit can cause the drive machine connected to the drive shaft 1 to stop, thereby preventing clutch slippage from occurring, until the temperature of the oil within the oil bath 30 drops below a second threshold value, which is lower than the first threshold value.

[0042] Oil bath clutches can overcome the shortcomings of current torque limiters that operate in dry conditions.

[0043] The performance of a universal joint with an oil bath clutch can be further improved by providing a sensor system associated with the universal joint 5. The sensor system can include a single sensor or an array of sensors. In some embodiments, one or more temperature sensors are provided to directly detect the temperature of the oil bath contained in the oil bath 30, as described above, or to detect the temperature of a portion of the universal joint 5 that is dependent on the temperature of the oil bath. For example, the sensor can be used to inform the operator of a machine incorporating the universal joint that an abnormal condition has occurred, which has caused the oil bath to overheat. As mentioned, this can occur, for example, if the clutch is slipping for an extended period of time, if the relative speed between the yoke 7A and the hub 21 is too high, or if the clutch is slipping too frequently.

[0044] exist Figure 4 and Figure 5 A first embodiment of a joint with a temperature sensor is shown in FIG. Figure 4 A side view of a universal joint 7 applied to one end of the telescopic shaft 3 of the drive shaft 1 is shown. The universal joint 7 may be as shown in FIG. Figures 1 to 3 Configure as described. Figure 4 Also shown is a power take-off 71 of, for example, a tractor, comprising a plurality of splined profiles 59 (see FIG. Figure 2 ) in the spline shaft 73.

[0045] A temperature sensor is applied to the universal joint 7 in an appropriate position. Figure 4 In the embodiment illustrated in FIG, the temperature sensor is embedded in a resin housing that is applied to the torque limiter 25, more specifically, in the illustrated case, to the outer surface of the enclosure 31. The protective housing that houses the temperature sensor is denoted by reference numeral 75. The protective housing brings the active portion of the sensor into direct contact with the outer surface of the enclosure 31.

[0046] In this arrangement, the temperature sensor is adapted to detect the temperature of the surface of the closing body 31 , inside which there is an oil bath in which the torque limiter clutch 25 is immersed.

[0047] Figure 5 A functional block diagram showing the components of a joint sensing device.

[0048] Since the temperature sensor is located on the universal joint 7 and rotates integrally therewith, the detected signal must be transmitted to a receiving device capable of utilizing the signal, for example, to issue a temperature signal via a human-machine interface, or to interface with an alarm system so that the operator of the machine on which the universal joint 7 is installed can intervene in the event of overheating of the oil bath, and also to obtain statistical data on the operation of the clutch.

[0049] The polymer resin housing notably houses a microcontroller electronic board, a radio module operating at a suitable frequency (eg 2.4 GHz), and a power source (eg batteries and / or “energy harvesting” technology) ensuring a suitable duration, eg approximately 3 years.

[0050] exist Figure 5 The following components are schematically shown housed in housing 75: temperature sensor 77, signal conditioning circuitry 79, microcontroller processing system 81, power supply 83, battery 84, and radio module 85.

[0051] Figure 5 The figure also shows another sensor 87, which is suitable for detecting a parameter indicative of the slipping state of the clutch of the torque limiter 25. In some embodiments, the sensor 87 can be a vibration sensor, such as a single-axis, dual-axis, or tri-axis accelerometer. The signal from the vibration sensor 87 can be used to detect and report the slipping state of the torque limiter clutch 25.

[0052] Signals detected by sensors 77 and 87 are transmitted via radio from radio module 85 to radio module 91, which can be mounted on a structure stationary relative to the machine where universal joint 7 is located. Radio module 91 interfaces with microcontroller 93 and data lines via transceiver module 96. Reference numeral 97 denotes a power source for electronic components 91, 93, and 96, and reference numeral 95 denotes a connector. In addition to the data lines, an external power source can be introduced into the connector, allowing power supply 97 to power modules 96, 93, and 91.

[0053] To reduce energy consumption, data transmission can be activated only when necessary, for example, only when a temperature sensor detects a temperature above a threshold. In this case, radio transmission module 85 is activated, and otherwise remains in standby mode, thereby reducing energy consumption. Sensors can also remain in standby mode and only be activated under specific conditions to reduce energy consumption.

[0054] As mentioned, in a particularly advantageous embodiment, temperature sensor 77 contacts an outer surface of enclosure 31 or another portion of the sensor. For this purpose, it is sufficient for the outer surface to be sufficiently flat to ensure proper contact of the sensor's sensitive element for mounting the sensor. In other embodiments, the sensor can be configured to directly sense the temperature of the oil in oil bath 30. In this case, enclosure 31 or another portion of the clutch housing can be perforated to allow passage of the sensor contacts and access to the interior of oil bath 30.

[0055] In some embodiments, the sensor associated with the joint 7 can be combined with another sensor or sensor group associated with the drive shaft and used to detect other useful parameters. WO-A-2020 / 222210 discloses an example of a drive shaft with onboard sensors. These sensors can be used to detect, for example, the rotational speed of the drive shaft, the torque transmitted, vibration, the tilt angle of the joint, temperature, etc. The temperature sensor 77 and / or the vibration sensor 87 can share some of the electronic devices associated with the drive shaft for power and data transmission.

[0056] In reference Figure 4 and Figure 5 In the embodiment described, the sensor or sensors associated with the universal joint 7 are fixed to the universal joint itself and rotate with it. This is advantageous from the perspective of data accuracy and sensor simplicity, but requires a power supply to be installed on the joint and requires radio data transmission.

[0057] Alternatively, the sensor or sensors dedicated to the universal joint 7 can be arranged in a position at rest relative to the machine on which the joint is mounted, ie in a non-rotating position. Figure 6 and Figure 7 An embodiment of this type is schematically shown in FIG. In this embodiment, the universal joint 7 is associated with a protective cover 101 for accident protection. The protective cover 101 is stationary, that is, it can be fixed, for example, relative to the vehicle to which the power take-off 71 belongs.

[0058] The housing 103 can be mounted on the protective cover 101, and the temperature sensor and possible slip detection sensor are housed inside the housing. Figure 7 The temperature sensor again indicated by reference numeral 77 in the functional block diagram may be an infrared sensor, the sensitive element of which is Figure 6 Indicated by reference numeral 107. This temperature sensor is, for example, facing the closure 31 of the torque limiter 25 in order to detect the temperature of the outer surface of the closure. The temperature sensor and the associated electronics can be powered via a wired connection 105, which also provides data transmission.

[0059] The protective cover 101 may have a special cutout, towards which the sensitive element 107 of the temperature sensor 77 faces, in order to correctly read the surface temperature of the closing body 31 or another part of the torque limiter, which temperature depends on the temperature of the oil contained in the oil bath 30 .

[0060] A sensor capable of providing information about the slip state of the clutch of the torque limiter 25 may be housed in the same housing 103. Figure 7 This sensor, again denoted by reference numeral 87, may be a sensor suitable for detecting the number of revolutions. Sensor 87 may, for example, detect the number of revolutions of hub 21 and yoke 7A, and thus the number of revolutions of closing body 31 of torque limiter 25. The difference in the number of revolutions of hub 21 and closing body 31 indicates clutch slippage. If the number of revolutions of shaft 73 is provided by another onboard sensor on the machine to which universal joint 7 is mounted, sensor 87 may be configured to read only the number of revolutions of the elements downstream of the clutch, such as the number of revolutions of closing body 31 or yoke 7A.

[0061] Figure 7 The block diagram in the example briefly illustrates Figure 6 The same numbers refer to the components of the sensor system in the configuration of Figure 5 Parts identical or equivalent to those illustrated in and described above. In particular, Figure 7 In the figure, the autonomous power supplies of the radio module and the sensors are omitted, since they are connected to an on-board power supply 97 on the machine. The microcontroller processing system 81 is connected to the transceiver module 96 and the power supply 97 via cables.

[0062] refer to Figures 4 to 7 The purpose of all the embodiments described is to generate an alarm or notification that warns the operator of the machine on which the universal joint 7 is mounted of any slippage which, if prolonged, could increase the temperature of the clutch to a value that could cause damage.

[0063] This signal allows the operator to quickly change operating parameters on the machine (e.g., a tractor) to prevent damage to the clutch. For example, the operator can reduce the rotational speed of the motor, disconnect the power take-off, or reduce the forward speed of the tractor.

[0064] The warning or notification can be transmitted to the operator, for example, via a display in the cab, or via another display connected to the CAN bus network, or even on a mobile device (such as a smartphone or tablet). Alternatively or in combination, a light signal can be provided via a special lamp or an acoustic signal can be provided.

[0065] In some embodiments, the alarm signal generated by the detection of the above-mentioned sensor can also directly and automatically intervene in the control of the machine (tractor, etc.) where the universal joint 7 is located, and modify the operating parameters of the machine itself.

[0066] All solutions described can incorporate connection systems based on Bluetooth, NFC or similar technologies.

[0067] If operating conditions do not allow the implementation of the above functions on the sensor control unit, the same functions can be performed by remote means.

[0068] Connected systems can support a variety of functions, such as real-time verification of operating parameters and notification of any alarm conditions, overall plant failures or abnormal conditions.

[0069] Through the remote telemetry control unit, the parameters of the torque limiter or any other component can also be stored in the cloud to build a historical data database for post-processing, statistical analysis or other purposes.

[0070] All of the above functions can be combined with the functions provided in a drive shaft of the type described in WO2020 / 222210.

Claims

1. A universal joint comprising: First yoke; the second yoke; a cross connecting the first yoke and the second yoke; a hub coaxial with the first yoke; a torque limiter interposed between the hub and the first yoke, wherein the torque limiter includes a clutch housed in an oil bath; wherein the first yoke is integral with a closing flange of the oil bath; wherein the oil bath is closed on a side opposite to the closing flange by a closing body, the hub extending through the closing body; The clutch comprises: a series of first clutch plates torsionally connected to the hub, a series of second clutch plates torsionally connected to the first yoke, and at least one elastic member pressing the first clutch plates and the second clutch plates against each other; wherein the first clutch plates and the second clutch plates are immersed in an oil bath and interleaved with each other; and wherein the hub is supported in the oil bath by a first bearing and a second bearing.

2. The universal joint according to claim 1, wherein: The first bearing is interposed between the closing body and the hub, and the second bearing supports the hub relative to the yoke.

3. The universal joint according to claim 1 or 2, wherein: The first clutch plate is connected to the hub via a spline profile.

4. The universal joint according to one or more of the preceding claims, said first bearing and said second bearing being rolling bearings.

5. Universal joint according to one or more of the preceding claims, wherein: The first bearing is located outside the hub and is received in a seat in the enclosure.

6. The universal joint according to claim 5, wherein: The second bearing is received in an axial bore of the hub and engages a pivot shaft extending into the hub and integral with the first yoke.

7. The universal joint according to claim 6, wherein: The axial hole is a through hole; wherein preferably, a closing plug is arranged in the axial hole and positioned between the second bearing and the distal end of the hub opposite to the first yoke, the distal end forming a mechanical connection with the power output device; wherein the mechanical connection preferably includes a spline profile.

8. Universal joint according to one or more of the preceding claims, wherein: The enclosure comprises: a bottom wall opposite the first yoke, wherein the hub extends through the bottom wall; and An annular peripheral wall surrounds the oil bath chamber, the annular peripheral wall being coaxial with the hub and sealingly connected to the closure flange.

9. Universal joint according to one or more of the preceding claims, wherein: The closure flange and the closure body are coupled to each other by means of a plurality of screws, preferably associated with a sealing gasket.

10. Universal joint according to one or more of the preceding claims, wherein: The oil bath chamber is sealingly closed by a sealing gasket which is accommodated in a seat in the closing body and surrounds the hub.

11. Universal joint according to one or more of the preceding claims, wherein: The hub comprises a spline profile forming a torsional coupling with the power take-off, a locking member being provided for coupling the spline profile to the power take-off.

12. Universal joint according to one or more of the preceding claims, comprising a temperature sensor.

13. The universal joint according to claim 12, wherein: The temperature sensor is applied to the outside of the oil bath room and is suitable for measuring the temperature of the walls that bound the oil bath room, wherein preferably, the temperature sensor is a sensor that is suitable for measuring the temperature of the walls that bound the oil bath room without contact, or the temperature sensor is in contact with the walls that bound the oil bath room, or is in contact with the oil contained in the oil bath room.

14. A universal joint according to one or more of the preceding claims, comprising a vibration sensor, or a relative rotation sensor between the hub and the yoke; wherein preferably, the vibration sensor is integral with a component of the universal joint, in particular with the first yoke; and wherein preferably, the relative rotation sensor is suitable for measuring the relative speed between the hub and the first yoke.

15. System comprising a universal joint according to one or more of the preceding claims and a protective cover for said universal joint, said protective cover being suitable for being fixed to a rest part. 16 . The system according to claim 15 , comprising a temperature sensor fixed to the protective cover and adapted to measure the temperature of the wall of the universal joint without contact, the temperature sensor preferably being an infrared sensor.

17. The system of claim 15 or 16, comprising a speed sensor fixed to the protective cover and adapted to detect a difference in rotational speed between the hub and the first yoke.

18. A drive shaft comprising: - a telescopic shaft having a first end and a second end; - a first universal joint associated with a first end of said drive shaft; as well as - a second universal joint associated with the second end of said drive shaft; One of the first universal joint and the second universal joint is a universal joint according to one or more of claims 1 to 14.

19. The drive shaft of claim 18, wherein: The second yoke is torsionally connected to the telescopic shaft, and the hub forms a coupling for a power take-off.

Images