Device for temperature monitoring of a sliding hub

Abstract

The invention relates to a device for monitoring the temperature of a sliding hub. The device is characterized in particular by the fact that the friction linings of the sliding hub are protected from overheating when the preset torque is exceeded. For this purpose, the sliding hub has at least one strip and / or one disc made of a bimetallic material. The strip or disc is arranged such that, as the temperature increases, it bends or warps relative to at least one component of the sliding hub. Furthermore, at least one region of the strip or disc, as the temperature increases, is an object to be detected, a component of a signal transmitter, an actuating element of a switching device, and / or an actuating element of a push button.

Description

[0001] The invention relates to a device for monitoring the temperature of a slip hub.

[0002] Slip hubs and slip clutches are load-holding frictional torque limiters. As soon as a preset torque is reached, the slip hub automatically interrupts the power flow by overcoming the static friction of the friction linings in the slip hub. A drive element mounted frictionally between the friction discs, such as a drive pinion, pulley, or similar, slips in the hub, thus protecting the system in question or sensitive machine parts from overload. The slip hub is thus an adjustable safety clutch that slips under frictional engagement when the set torque is exceeded. Once the overload phase is over, power transmission is restored.

[0003] DE 87 04 842 U1 discloses a torque limiter with a drive element clamped between friction linings by means of at least one disc spring loaded via a nut. A thrust ring between the disc spring and the nut, which has several recesses of limited depth, into which the free ends of adjusting pins arranged on the nut engage, facilitates torque adjustment.

[0004] EP 1 826 428 A1 discloses a torque release mechanism for off-road vehicles, comprising a drive pulley, a sprocket, at least one friction disc, a fastening disc, and an elastic element. The friction of the friction disc is used to protect a transmission chain of off-road vehicles from breakage if the torque exerted on the chain exceeds a predetermined value. For this purpose, a fastening element is provided that presses the elastic element against a fastening plate. The fastening plate and a friction plate are in contact with the sprocket.

[0005] The invention defined in claim 1 is based on the object of protecting the friction linings of a slip hub from overheating when the preset torque is exceeded.

[0006] This problem is solved with the features listed in patent claim 1.

[0007] The device for temperature monitoring of a slip hub is particularly characterized by the fact that the friction linings of the slip hub are protected from overheating if the preset torque is exceeded.

[0008] For this purpose, the sliding hub comprises at least one strip and / or disc made of a bimetal. The strip or disc is arranged such that, as the temperature rises, the strip or disc bends or curves relative to at least one component of the sliding hub. Furthermore, as the temperature rises, at least one region of the strip or disc becomes an object to be detected, a component of a signal generator, an actuating element of a switching device, and / or an actuating element of a button.

[0009] Slip hubs are characterized in particular by their simple design, high reliability, and comparatively low investment costs. The disadvantage is that if the preset torque in the drive is exceeded and the frictionally mounted drive element slips, the friction linings of the slip hub are quickly destroyed by overheating. The temperature monitoring device of a slip hub advantageously ensures that the overload event is recognized, thus protecting the friction discs from further damage. The slip hub thus has an integrated shutdown device that automatically shuts down the affected system in the event of an overload in the drive train, thus protecting the installed slip hub or slip clutch from inevitable destruction. Furthermore, the overload event is indicated to the user.The basis for the implementation of overload protection for slip hubs is the strip or disc that triggers a switching process.

[0010] In the event of an overload in a drive train with a built-in torque limiter, if a certain torque is exceeded, the drive element, which is frictionally mounted between friction linings, for example in the form of a gear ring or a belt pulley, slips. Depending on the torque to be transmitted and the preset friction force, slipping of the drive element can lead to temperatures of, for example, over 300°C being reached on the drive element after just a short time. At these temperatures, the friction linings begin to suffer permanent damage, begin to vitrify, and as the temperature continues to rise, they literally burn up. As a result, friction linings damaged in this way no longer provide any further protection against a preset, defined torque. To prevent damage to the friction linings, a shutdown device is provided for the defective drive train in question at temperatures below 300°C.The proposed slip hub with automated shutdown behavior is based on a thermomechanical switching process caused by a bimetal strip or disc. Due to the immediate strong heating of the entire slip hub in the event of an overload, the strip or disc changes its shape in such a way that when a defined temperature is reached on the friction linings, a switch is activated, which shuts down the system to be protected. A bimetal strip consists of two superimposed layers or sheets of different metals. The layers or sheets are connected to one another by means of a material bond or form-fitting connectors. Due to different thermal expansion coefficients of the metals used, one of the layers or sheets expands more than the other layer or sheet, causing the strip or disc to bend.Different material compositions, layer thicknesses, or sheet thicknesses can be used, which trigger the shutdown process when different temperatures are reached—from even slight deviations from the operating temperature up to a maximum temperature specified for slip hubs. This allows for a possible overload to be quickly detected depending on the application.

[0011] Slip hubs are used in a wide variety of applications. The temperature monitoring device for a slip hub also advantageously protects slip hubs with continuous slip from overheating.

[0012] The slip hub can, for example, have a disc in the shape of a circle or a circular ring made of bimetal, which bulges in the event of an overload and the resulting temperature increase. The circular disc can thus form a plate shape with a raised edge or the shape of a spherical cap. The circular disc can thus form a spherical zone. The disc can, for example, move an axially displaceable cap when the temperature increases, thus actuating a switch in the form of an emergency stop.

[0013] This allows a strip or disc made of a bimetal to be used advantageously to monitor the temperature of a slip hub.

[0014] Advantageous refinements of the invention are set forth in the following developments and embodiments. These can develop the device for temperature monitoring of a friction hub individually or in combination.

[0015] In one embodiment, the bimetal disc can have a concave curvature, resulting in a bimetal switch with a snap action. At a certain temperature, the concave curvature suddenly becomes convex. The disc can be shaped like a circle or an annulus.

[0016] In one embodiment, the bending or curved portion of the strip or disc is an actuating element of a mechanically operated switch or button. This can, in particular, be an emergency stop switch.

[0017] In one embodiment, the bending or bulging area of ​​the strip or disc is a detectable object of a light barrier. This interrupts a light beam, generating an electrical signal. This signal is used to actuate a switching device, such as an emergency stop switch.

[0018] In one embodiment, the curved or arched portion of the strip or disc has at least one permanent magnet, which, by means of a Hall sensor, acts as a contactless signal transmitter. The signal thus generated is used to actuate a switching device, such as an emergency stop switch.

[0019] In one embodiment, the strip or disc is arranged such that, as the temperature increases, the strip or disc bends or arches relative to a hub having at least one friction ring as part of the slip hub.

[0020] In one embodiment, the Hall sensor, the light barrier or the mechanically operated switch or button is connected to the slip hub with a shutdown device of the drive train.

[0021] In one embodiment, the drive train comprises the slip hub with a drive element arranged between friction rings.

[0022] In one embodiment, a friction ring is a friction lining on the hub.

[0023] In one embodiment, a first end region of the strip or a first region of the disc is firmly fixed. A second region of the strip or disc is bent or curved away from the hub when the hub temperature is elevated. Furthermore, the second region of the strip or the second region of the disc is the object to be detected, the component of the signal generator, the actuating element of the switching device, and / or the actuating element of the button.

[0024] An embodiment of the invention is shown in principle in the drawings and is described in more detail below.

[0025] They show: Fig. 1 a slip hub with a device for temperature monitoring, Fig. 2 a disc made of a bimetal on a slip hub at low temperature of friction linings of friction discs and Fig. 3 a disc made of a bimetal on a slip hub at high temperature of friction linings of friction discs.

[0026] A device for monitoring the temperature of a slip hub essentially consists of at least one strip and / or one disc 10 made of a bimetal.

[0027] The Fig. 1 shows a sliding hub with a temperature monitoring device in a schematic representation.

[0028] The torque limiter has a hub 1 with a circular stop 2 for a drive element 3. The drive element 3 can be a drive pinion or a belt pulley, for example. A bushing 4 can be located between the drive element 3 and the hub 1. The hub 1 also has a thrust ring 5, so that the drive element 3 is located between the stop 2 and the thrust ring 5. A friction ring 6 is located between the stop 2 and the drive element 3, as well as between the drive element 3 and the thrust ring 5. A thrust washer 8, which is acted upon by screws 9, engages the thrust ring 5 via a disc spring 7. The torque is adjusted using the screws 8, the thrust washer 8, the spring 7 and the thrust ring 5.As soon as this preset torque is reached, the slip hub automatically separates the power flow by overcoming the static friction of the friction linings of the friction discs in the form of friction rings 6 and the drive element 3, which is frictionally mounted between the friction rings 6, slips in the hub 1.

[0029] It shows the Fig. 2 a disc 10 made of a bimetal on a slip hub at low temperature of friction linings of friction rings 6 and the Fig. 3 a disc 10 made of a bimetal on a slip hub at high temperature of friction linings of friction rings 6 each in principle representations.

[0030] On the side of the stop 2, which is opposite the side with the friction ring 6, the disc 10 in the form of a circular disc made of bimetal is arranged. This disc 10 bulges in the event of an overload and the resulting temperature increase, thus changing its shape in a defined manner. The bulging and thus bent area of ​​the disc 10 simultaneously serves as an actuating element of a mechanically actuated switch or button 12, whereby an axially displaceable cover cap 11 is moved away from the stop 2. This cover cap 11 is connected to the switch or button 12 as an emergency stop switch 12, which, for example, switches off a system connected to the drive element 3. The cover cap 11 also serves to position the bimetal disc 10 and protect it.

[0031] A spring element 12 can engage the cover cap 10 such that the spring force of the spring element acts in the direction of the stop 2. When the temperature drops, the curvature of the disc 10 decreases, so that the spring force pushes the cover cap 11 toward the stop 2 and the switch or button 12 opens again. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 87 04 842 U1

[0003] EP 1 826 428 A1

[0004]

Claims

[1] Device for temperature monitoring of a slip hub, characterized by that the sliding hub has at least one strip and / or one disc (10) made of a bimetal, that the strip or the disc (10) is arranged such that the strip or the disc (10) bends or arches with increasing temperature in relation to at least one component of the sliding hub, and that at least one region of the strip or the disc (10) is an object to be detected, a component of a signal generator, an actuating element of a switching device and / or an actuating element of a button (12) with increasing temperature. [2] Device according to claim 1, characterized by that the disc (10) made of a bimetal has a concave curvature, so that the disc (10) made of the bimetal is a bimetal switch with jump behavior. [3] Device according to at least one of claims 1 and 2, characterized bythat the bending or arching region of the strip or disc (10) is an actuating element of a mechanically operated switch or button (12). [4] Device according to at least one of claims 1 to 3, characterized by that the bending or bulging region of the strip or disc (10) is a detectable object of a light barrier. [5] Device according to at least one of claims 1 to 4, characterized by that the bending or arching region of the strip or disc (10) has at least one permanent magnet which is a contactless and contactless signal generator by means of a Hall sensor. [6] Device according to at least one of claims 1 to 5, characterized bythat the strip or the disc (10) is arranged such that the strip or the disc (10) bends or arches with increasing temperature in relation to a hub (1) with at least one friction ring (6) as a component of the slip hub. [7] Device according to at least one of claims 1 to 6, characterized by that the Hall sensor, the light barrier or the mechanically operated switch or button (12) is connected to a shutdown device of the drive train with the slip hub. [8] Device according to at least one of claims 1 to 7, characterized by that the drive train has the slip hub with a drive element (3) arranged between friction rings (6). [9] Device according to at least one of claims 1 to 8, characterized by that a friction ring (6) is a friction lining on the hub. [10] Device according to at least one of claims 1 to 9, characterized bythat a first end region of the strip or a first region of the disc (10) is firmly fixed, that a second region of the strip or of the disc (10) is bent or curved away from the hub (1) in relation to the hub (1) when the temperature of the hub (1) is increased, and that the second region of the strip or the second region of the disc (10) is the object to be detected, the component of the signal generator, the actuating element of the switching device and / or the actuating element of the button (12).

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