Self-resetting safety element, and coupling comprising a plurality of said safety elements

Abstract

The invention relates to a safety element (5a) with a self-resetting property for a coupling (1) comprising two coupling elements (2, 3), wherein, in an engaged state, a torque can be transmitted between the two coupling elements (2, 3), and wherein, by means of the safety element and depending on the torque, the two coupling elements (2, 3) can be shifted into a disengaged state and can automatically be reset to the engaged state. The invention also relates to a coupling comprising at least one safety element (5a) according to the invention.

Description

[0001] Self-resetting safety element and coupling comprising several of these safety elements

[0002] The invention relates to a safety element according to claim 1, which is provided for a coupling. It has the property of disengaging in a torque-dependent manner in the event of a malfunction due to overload. Furthermore, the safety element can then automatically return to the engaged state. Furthermore, the invention relates to a coupling comprising several safety elements according to the invention, in particular a torque-dependent switchable shaft coupling.

[0003] The safety element is designed for a coupling that comprises two coupling elements that can be regarded as coupling halves. In the case of a shaft coupling, a torque can be transmitted between the two coupling elements in the engaged state, wherein the two coupling elements can be automatically switched into the disengaged state by means of the safety element in a torque-dependent manner, i.e. when a defined torque is exceeded, with the proviso that the safety element comprises: a plunger that is displaceable in its axial direction by means of a provided bearing in order to provide the engaged state or the disengaged state of the coupling in the assembled state, a locking element that bears against the plunger, for example a ball, wherein the locking element preferably bears against a front end of the plunger, a spring device,by means of which a spring force can be transmitted into the tappet and further into the locking element, for example a disc spring assembly, wherein the tappet is provided with a shoulder element which projects in the radial direction on the tappet, preferably a circumferential annular shoulder element, wherein at least one transmission body is provided which is in contact with the shoulder element on the one hand and furthermore with at least one pressure body and cooperates therewith, wherein the transmission body is for example a rolling body and preferably the pressure body is designed as a circumferential annular pressure body, for which the pressure body has a deflection surface and the shoulder element comprises two functional surfaces, namely an inclined surface which also points in the axial direction and a laterally arranged rest surface,wherein the transmission body, in the engaged state of the coupling, is in contact with the inclined surface of the shoulder element, transmitting the spring force, while in the disengaged state of the coupling (neutral) it bears against the lateral resting surface of the shoulder element, and with the further proviso that, in the assembled state, the plunger and the locking element are assigned to a first of the two coupling elements of the coupling, and that a locking area is assigned to the other, second coupling element, e.g. a conical or dome-shaped opening, which locking area is designed to be complementary to the locking element. The locking area expediently forms a component of the safety element or is assigned to it.

[0004] Safety elements of this type and devices equipped with them

[0005] Couplings are used for heavy-duty machinery, for example, for machines in mining, the construction industry, or in conveyor systems, e.g., cranes, such as container cranes. For example, a container crane in a modern port terminal faces special requirements due to increasing automation.

[0006] Also known are safety elements which, after a fault, are in the disengaged position and the coupling elements are separated, cannot automatically return to an engaged state. With this type of safety element, resetting must be carried out manually, which is labor-intensive and always requires an operator on site. An example of this is US 2010 / 0224713 A1, which proposes a safety element and a coupling equipped with it. Each safety element is arranged on one coupling half and comprises a plunger which, when engaged, can transmit a torque to the other coupling half by spring force in an advanced position. After a fault, the plungers and locking elements of all safety elements are pushed back into a position in which no more spring force can be transmitted to the plunger.The transmission of force from the spring mechanism is interrupted or neutralized. To switch the clutch back to torque-transmitting operation, the transmission of spring force to the tappet must be restored and the neutralization canceled. With the current state of the art, this switching can only be accomplished by manual intervention, which can be achieved, for example, by a targeted hammer blow and requires operating personnel.

[0007] A generic safety element with a self-resetting function was proposed by the applicant in DE 10 2019 110 297 B3. With this safety element or a coupling equipped with it, the coupling can be re-engaged after a malfunction when the coupling halves are separated, without an operator having to manually actuate each safety element. This prior art provides a mechanism comprising an actuating lever arranged on the outside of the housing, which can be pivoted against the plunger by spring force in order to return to the engaged state. The present application now pursues another improved solution to this problem.

[0008] The invention is based on the object of providing a safety element which, when installed in a clutch, enables re-engaging after a disengagement and separation of the torque transmission for safety reasons, without the need for an operator who would have to manually reset each of the many safety elements on site at the operating point of the clutch.

[0009] According to the invention, the object is achieved in that the rest surface of the shoulder element of the tappet is further developed into an action surface which has an inclination relative to the axial direction of the tappet, namely is inclined by an angle a relative to the axial direction of the tappet.

[0010] The direction of the proposed inclination of the action surface corresponds to the direction in which the inclined surface of the shoulder element is inclined. The action surface deflects the spring force and also causes a transmission of the spring force. The transmission is designed such that the plunger is subjected to only a defined, low force component in the axial direction, so that re-engagement in this direction is gentle on the material.

[0011] The appropriate degree of inclination of the action surface can be determined empirically. The locking elements can only be moved back into the engagement areas when the speed difference between the clutch halves is small, because this allows for re-engagement with a low restoring force on the plunger in a way that protects the material.

[0012] Even if the transmission element is designed as a rolling element, it does not necessarily have to perform a purely rolling motion; instead, it may have sliding components with the tappet or the thrust elements. This involves a combination of rolling and sliding.

[0013] This new concept allows for the provision of safety elements that are designed for different torques and / or graded according to different sizes. Practically, series of safety elements can be provided. For each safety element in a series, a suitable angle for the inclination of the action surface of the plunger's shoulder element is advantageously defined. The angle can be determined empirically, for example, for each size or for each desired torque of the respective safety element.

[0014] When a clutch is in operation, both clutch elements (clutch halves) rotate and can transmit a certain maximum torque. The overall performance of the clutch depends on the properties of the safety elements used and their number. This results in a cumulative performance corresponding to the number of safety elements present in the clutch. If the maximum torque is exceeded, the locking elements and plungers of all safety elements simultaneously move back from the engagement areas against the force of the spring device and prevent further torque transmission. The transmission body, which is preferably a ball, no longer lies completely neutrally on the action surface of the plunger. This can introduce a force component into the plunger in the axial direction, advancing it towards the engagement area.

[0015] In the safety element of US 2010 / 0224713 A1 and DE 10 2019 110 297 B3, the rest surface is provided on the shoulder element of the plunger. When the transmission bodies (balls) rest on the rest surface in the disengaged state, the movable pressure body can still press against the balls, but the balls can no longer deflect force into the plunger via the rest surface. The spring force caused by the spring device is neutralized. The coupling halves are separated as long as the balls remain in contact with the rest surface. Both the safety element of US 2010 / 0224713 A1 and that of DE 10 2019 110 297 B3 require a great deal of effort, either in terms of personnel or equipment, in order to act on the plunger from the outside.

[0016] In contrast, the new solution proposed here changes the function of the rest surface by transforming it into an action surface. The action surface is expediently inclined at an acute angle to the axial direction of the plunger. When the movement of the transmission balls is deflected at the action surface, a defined transmission ratio is in play due to the angle a of their inclination. By varying the angle of inclination a, the transmission ratio of the action surface can be adjusted. The aim is to direct a relatively low axial force into the plunger and allow it to advance towards its engaged position. The transmission ratio is expediently such that the locking elements can only be moved back into the engagement areas when the speed difference between the coupling halves is small.Re-engagement should only be permitted with a significantly reduced return force on the tappet.

[0017] As a result, a clutch which is equipped with safety elements according to the invention can now be automatically re-engaged in the event of a malfunction which has led to disengagement and an interruption in the transmission of torque, simply by slowly restarting the driving clutch element. Before re-engaging, it is always advisable to eliminate the problem which is responsible for the torque being exceeded. It is advisable to only then slowly start the clutch again in order to automatically re-engage. The driving clutch element is set in rotation so slowly that the slight restoring axial force transmitted to the plunger is sufficient to advance all of the locking elements of one clutch half into the locking areas of the other clutch half and thus enable torque to be transmitted again.

[0018] The gear ratio, adjusted by the inclination of the operating surface, is specifically selected so that re-engagement of the locking element is only possible with a defined, small speed difference. This process is therefore gentle on the material. As mentioned, it is advisable to first bring the clutch to a complete standstill, and then, before restarting, the cause of the torque overshoot is identified and eliminated.

[0019] A clutch equipped with the proposed safety element can thus advantageously be put back into operation without requiring an on-site operator to manually operate each plunger or to move it to its advanced position using complex external mechanisms. It is advisable to perform the movement slowly enough so that the axial force component, which is small due to the gear ratio, is sufficient to move the plunger to its advanced, engaged position. The clutch can then transmit the torque for which it was designed.

[0020] The angle a of the inclination of the resting surface of the shoulder element is expediently in a range from 3 ° to 12 ° , preferably it is in a range from 5 ° to 10 ° and particularly preferably in a range from 7 ° to 8 ° .

[0021] Advantageously, a first axially movable pressure body and a second pressure body are provided, wherein the second pressure body is arranged fixedly relative to the housing.

[0022] Advantageously, both pressure bodies are directly or indirectly spring-loaded, with at least one of the two pressure bodies having an inclined deflection surface, with each of the deflection surfaces being in contact with the transmission body, and with at least the deflection surface of one of the two pressure bodies being arranged inclined at an angle, preferably an acute angle, to a radial plane.

[0023] The bearing of the plunger can advantageously be integrated into a housing, wherein the housing has a fastening means designed for easy mounting of the safety element on a coupling element. If the housing has a cylindrical shape, then the fastening means can be, for example, an external thread on the housing, which can be screwed into a complementary internal thread of the coupling element.

[0024] The housing is expediently provided with an adjustment means by means of which, in the assembled state, its axial position relative to the supporting coupling element can be adjusted. For the proposed safety element, it is considered important to enable the axial position of several components which are arranged in a row when assembled to be adjustable. The components in question are the plunger, the locking element and the locking area. They should be arranged with as little play as possible or with a defined small amount of play relative to one another. The plunger and the locking element are located in the housing, which is assigned to one coupling element, while the locking area is assigned to the other coupling element. This results in certain positional tolerances between the aforementioned components in their axial direction, which can be compensated for by the adjustability of the housing.

[0025] The aforementioned measure is considered not only dependent on the solution to the underlying problem stated above, but also as an independent inventive solution to the differing technical problem arising from the positional tolerances of the aforementioned components. Therefore, based on the preamble of claim 1, a safety element is hereby proposed which is additionally provided with the aforementioned adjustment means for the housing in order to adjust its axial position relative to the supporting coupling element and indirectly to adjust the axial position of the components: plunger, locking element, and locking area relative to one another.The aforementioned independent solution for the adjustability of the components mentioned is supplemented by the latching area being designed as an exchangeable latching area element which has a fixed positioning aid, wherein the positioning aid interacts with a stop means of the relevant coupling element in the assembled state.

[0026] Advantageously, in a coupling with a plurality of safety elements, each of the locking elements (e.g. ball) can be brought into contact with each of the engagement area elements without having to pay attention to an aligned position of the two coupling elements, because for example only one engagement area element would be suitably adjusted for each locking element.

[0027] Advantageously, a guide bush is assigned which, in the assembled state, serves to guide the plunger and / or to guide the locking element, wherein the guide bush is also assigned to the first coupling element concentrically to the plunger.

[0028] The guide bush can be assigned as a separate component or it is assigned as an integral part of the safety element, for example a housing part of the safety element.

[0029] The housing can have a closure element as a housing part, wherein the closure element acts as a counter bearing for the spring device and / or acts as a guide for the plunger and / or the locking element.

[0030] The closure element expediently comprises a means by means of which its axial position relative to the housing can be adjusted. The closure element is simply provided with a guide bore for the tappet and has an edge with an external thread. The external thread can serve as a means of fastening. In addition, the external thread can form the aforementioned means for adjusting the axial position. The external thread of the closure element expediently interacts with a matching internal thread provided in the housing, preferably this is a fine thread. Furthermore, an integrated securing element can be provided, e.g. a piece of aluminum which is let into a blind bore which is arranged in the region of the external thread transversely to it.The aluminum piece reaches into the area of ​​the external thread and is only deformed when the external thread is screwed into the internal thread of the housing, creating a stopping effect similar to the embedded plastic of a self-locking hexagon nut DIN 985, which is deformed during screwing and acts as a screw lock.

[0031] The spring device can comprise at least one disc spring, preferably a disc spring package consisting of several disc springs is provided.

[0032] The plunger and / or at least one of the pressure bodies can be provided on its deflection surface with at least one radially extending groove which, in the assembled state, acts as a guide for the transmission body.

[0033] The locking element and / or the locking area element are preferably made of a ceramic material.

[0034] The pressure body and / or the transmission body can be made of a ceramic material.

[0035] The static or stationary pressure body and the movable pressure body can alternatively be made from a metal alloy. They are expediently subjected to a treatment by means of which improved wear resistance can be provided. The transmission body can also be made from a metal alloy and subjected to a treatment in order to improve wear resistance. The treatment for the components mentioned can be a heat treatment, for example to harden pressure bodies and / or transmission bodies made from steel, or it can be a treatment in the form of a coating that applies a material that improves the wear properties, for example a coating with chromium, in particular a hard chromium layer.

[0036] Furthermore, it is advisable if the components within the housing are operated in the presence of a suitable lubricant.

[0037] For the tappet it is further proposed that it be composed of several parts, comprising at least one tappet shaft and a shoulder element which can be connected to it, in particular a shoulder ring. The shoulder ring can have a conical action surface or the conical action surface can additionally be provided with radial grooves. A suitable connection between the tappet shaft and the shoulder ring creates a defined, fixed relationship between the tappet shaft and the shoulder ring, in particular in the axial direction. The two-piece design has the advantage that the shoulder ring can be replaced separately. It is subject to particular wear during operation and may need to be replaced at a time when the tappet shaft can still be used. In this case the existing tappet shaft is simply provided with a new shoulder ring.In addition, it is possible to subject the shoulder ring to a specific treatment which improves its wear properties and to leave the tappet shaft untreated or to subject it to another suitable treatment.

[0038] Furthermore, a coupling is proposed comprising two coupling elements which can be rotated about an axis and which can be switched into a coupled state and a disengaged state, wherein in the coupled state a torque can be transmitted, wherein on one of the coupling elements at a defined diameter and concentric to the axis of rotation of the coupling element at least one safety element according to one of claims 1 to 16 (preferably axially or radially) is arranged and in the case of a plurality of arranged safety elements a defined distance between the safety elements is preferably provided, and wherein on the second coupling element at an identical diameter and concentric to its axis of rotation a corresponding number of latching area elements are arranged and at congruent distances as the safety elements.

[0039] Advantageously, a circumferential groove is provided on the second coupling element, which, in the disengaged state, interacts with the locking elements of the safety elements. The cross-section of the groove is expediently adapted to the cross-section of the locking element, for example, to the cross-section of a spherical locking element.

[0040] The invention is illustrated below by way of example in a drawing and described in detail with reference to several figures. They show:

[0041] Fig. 1 shows a coupling provided with six safety elements according to the invention,

[0042] Fig. 2 is a partial sectional view of a safety element according to the prior art mounted on a coupling and shown in the engaged state,

[0043] Fig. 3 is a partial sectional view of the known safety element of Fig. 2 in a fictitious separated state of the coupling,

[0044] Fig. 4 is a partial sectional view of a first embodiment of the safety element according to the invention mounted on a coupling and shown in the coupled state,

[0045] Fig. 5 is a partial sectional view of the embodiment of Fig. 4 in a different sectional plane in the coupled state,

[0046] Fig. 6 is a partial sectional view of the embodiment of Figs. 4 and 5 in a separated state of the coupling,

[0047] Fig. 7 is a perspective view of an alternative plunger for a second embodiment of the safety element according to the invention,

[0048] Fig. 8 is a perspective view of an alternative movable pressure body for the second embodiment of the security element according to the invention,

[0049] Fig. 9 is a perspective view of an alternative stationary pressure body for the second embodiment of the security element according to the invention.

[0050] Fig. 1 shows a clutch 1 according to the invention, which has two clutch elements 2 and 3 (clutch halves) that are movable relative to one another and can be switched depending on the torque. In the present example, the clutch elements 2 and 3 can be rotated about a rotational axis 4 of the clutch 1. Therefore, the clutch 1 is a shaft coupling. It is torsionally rigid and switchable. Switching is possible between an engaged and a disengaged state and occurs depending on the torque.

[0051] The coupling 1 is intended, for example, for drive trains of machines, such as machines in mining, the construction industry or in materials handling systems, such as cranes. In particular, it is intended for application in container cranes. In such machines, sudden overloads can occur that endanger components of the machine, such as motors, gearboxes, etc. In order to protect these, the proposed coupling 1 separates the power transmission between the two coupling elements 2 and 3, so that overloads are kept away from the aforementioned components of the machine and these are protected. The coupling 1 can therefore be referred to as a safety coupling or overload coupling.

[0052] To enable clutch 1 to fulfill its torque-dependent safety function, it is provided with six safety elements 5a according to the invention. Each safety element 5a has a specific torque transmission capacity. In the present example, the total torque transmittable by clutch 1 is based on six safety elements 5a, so that clutch 1 essentially has six times the capacity of a single safety element 5a.

[0053] The safety elements 5a are subject to wear. Certain components of the safety element 5a that are critical to operational safety are typically inspected regularly and replaced if necessary. To improve the service life of the safety element 5a according to the invention, they are provided with wear-reducing means, as follows.

[0054] The coupling element 2 carries the six safety elements 5a. For this purpose, it is designed like a flange. The positions for the safety elements 5a are distributed on the coupling element 2 on a circle (pitch circle) that is coaxial with the axis of rotation 4 of the coupling 1. Each safety element 5a is rotationally symmetrical and has a central axis 6a. It is positioned on the pitch circle of the coupling element 2 with the central axis 6a. In the present example, the central axes 6a of the safety elements 5a are arranged parallel to the axis of rotation 4 of the coupling 1 or the coupling element 2. Alternatively, safety elements 5a can also be arranged in a radial orientation on a coupling element, for example in order to obtain a coupling that acts in the axial direction.

[0055] Figures 2 and 3 show a safety element 5b which is part of the prior art and is attached to a flange-like coupling element 2. The coupling element 2 has a mounting plane 7 which is orthogonal to the axis of rotation 4 and the safety element 5b also has a defined mounting plane 8. In the mounted state shown, the mounting plane 8 of the safety element 5b is in contact with the mounting plane 7 of the coupling element 2. As a result, in this prior art the relative position of the coupling element 2 and the safety element 5b is fixed in the axial direction. The safety element 5b comprises a plunger 9 in a housing 10, wherein a housing edge 10a defines the mounting plane 8 of the safety element 5b. The plunger 9 is indirectly spring-loaded and presses against a detent ball 11. The detent ball 11 is as shown in Fig.2 is engaged in a locking area 12 which is arranged on the opposite coupling element 3 and is axially adjustable by means of an adjusting screw 13. The plunger 9 has a shaft on which a shoulder element 14 is provided around its circumference. The shoulder element 14 is in contact with balls as transmission bodies 15. Fig. 3 shows the disengaged state of the safety element 5b, in which a cylindrical rest surface 16 as part of the shoulder element 14 has come into contact with the transmission bodies 15. In this position, the transmission of a spring preload into the plunger 9 is neutralized. In order to switch back from the disengaged state to the engaged state, the plunger 9 must be advanced from the outside and the locking ball 11 must be pressed back into the locking area 12.

[0056] Fig. 4 shows a first exemplary embodiment of the safety element 5a according to the invention, which has a self-resetting function. By means of this function, it can be automatically switched from a disengaged state to an engaged state. For a coupling provided therewith, this means that it can be automatically switched from a separated state of the coupling halves to the engaged state. For the sake of simplicity, the same reference numerals are used for comparable features as previously in the description.

[0057] Fig. 4 shows in particular that the safety element 5a is mounted on a coupling element 2 in a different way than in the prior art. The proposed safety element 5a comprises a rotationally symmetrical plunger 9 which is modified compared to the prior art and on which the cylindrical rest surface is replaced by a truncated cone-shaped action surface which has an inclination relative to the axial direction of the plunger, in this case an angle of 7.5 ° to the central axis of the plunger 9. According to Fig. 4, a front end 17 of the plunger presses against a spherical locking element (locking ball 11), the plunger 9 being arranged in a housing 10 which has a bearing for the plunger 9 and enables its displacement in its axial direction. The internal structure in the housing 10 of the security element 5a corresponds at least largely to the structure of the known security element according to Figures 2 and 3.In contrast to this prior art, however, the safety element dispenses with providing a housing edge as a mounting plane for fixed positioning on the relevant coupling element 2 and, furthermore, the plunger 9 differs by the above-mentioned inclined action surface 49.

[0058] For mounting on the coupling element 2, the housing 10 is provided with a combined fastening and adjustment means 18, by means of which its axial position relative to the supporting coupling element 2 can be adjusted. The housing 10 is arranged coaxially with the tappet 9 and around the latter and has two end faces 10b and 10c. The end faces 10b and 10c form a bearing, which has bearing openings L1 and L2, respectively, which serve as guide bearings for the axial mobility of the tappet 9. A seal S1 and S2, respectively, is arranged in each of the bearing openings. The fastening and adjustment means is simply

[0059] 18 an external thread 19, which is provided on the outside of a cylindrical side wall 20 of the housing 10. The external thread 19 is expediently designed as a fine thread. To match this, the coupling element 2 is provided with a complementary internal thread 21, into which the external thread

[0060] 19 of the housing 10 can be screwed in. The screw connection consisting of the external thread 19 and the internal thread 21 has a dual function. On the one hand, it is used for assembly and fastening and, on the other hand, for the aforementioned axial adjustability. The axial position of the housing 10 determines the axial position of the tappet 9, which is arranged in a row with the detent ball 11 and in a row with the associated engagement area 12, which is arranged on the other coupling element 3. The appropriate screw-in depth for the housing 10 is found during assembly. What is desired is a play-free connection between the tappet 9 and the detent ball 11 and, consequently, a play-free connection between the detent ball 11 and the engagement area 12.

[0061] In this case, the plunger 9 is also indirectly subjected to a preload generated by a spring device 22 arranged in the housing 10. The spring device 22 comprises a disc spring assembly 23 arranged coaxially around the plunger 9.

[0062] Alternatively, the screw-in depth of the housing 10 can also be selected such that a slight play is provided between the plunger / locking ball / locking area during assembly, for example in order to only achieve freedom from play once the machine has warmed up and reached a predetermined operating state. A certain heat-induced expansion of the components involved can reduce or eliminate play to a defined extent. During assembly, the housing 10 can, for example, be screwed in with a defined torque in order to then turn the housing 10 back in the opposite direction by a defined angle and in this way create a defined play. The final screw-in depth of the housing 10 in the coupling element 2 is expediently secured. A suitable means 24 is provided for securing this, such as a threaded pin 25 in the example in Fig. 4, which is arranged in a bore 26 in the coupling element 2.When screwed in, the threaded pin 25 presses radially against the external thread 19 of the housing 10, fixing its position relative to the coupling element 2. To protect the external thread 19, an intermediate piece 27 made of aluminum, a soft metal, is provided in front of the tip of the threaded pin 25, which is pressed against the external thread 19 of the housing 10 without damaging it. The intermediate piece 27 is deformed, thereby achieving a stopping effect, similar to the plastic of a self-locking hexagon nut DIN 985, which is deformed during screwing in and counteracts the loosening of the screw connection.

[0063] The locking areas 12 for the locking balls 11 of each safety element 5a are arranged on the other coupling element 3. In the present example, the locking areas 12 are each designed as an exchangeable locking area element 28. The locking area element 28 has an external thread which is screwed into an internal thread of the coupling element 3. Each locking area element 28 has a locking recess 29, here a recess with a conical inner surface 30. Furthermore, each locking area element has a fixed positioning aid which in this example comprises a radially projecting collar 31. In the assembled state, the projecting collar 31 interacts with a radial surface of the coupling element 3, which serves as a stop means. The correct axial position is always defined for the locking area element 28.This eliminates the need to bring the two coupling elements into a specific rotational position relative to each other before engaging, as was the case with the prior art. The proposed engagement area elements 28 are manufactured with such a high quality and dimensional accuracy that the locking ball 11 of each safety element 5a of the coupling can interact with any mounted engagement area element 28. In this way, the proposed safety element 5a generally facilitates engagement.

[0064] Figs. 5 and 6, like Fig. 4, refer to the first embodiment of the safety element. It differs from the prior art by a modified plunger 9, whose second functional surface of the shoulder element 14 forms an action surface 49 that is inclined relative to the axial direction of the plunger 9. In the present example, the action surface is inclined by an angle a of 7.5° relative to the axial direction of the plunger 9.

[0065] In the example, the action surface 49 is arranged circumferentially on a shoulder ring 14a. This results in a truncated cone shape of the action surface 49.

[0066] In comparison to Fig. 4, Figures 5 and 6 show the first embodiment in a different sectional plane, whereby Fig. 5 refers to the engaged state and Fig.

[0067] 6 shows the disengaged state in which the plunger 9 and the detent ball 11 assume a retracted position; the coupling is separated. The detent ball has retreated from the engagement area. In Fig. 6, the engagement area element 28 is shown in simplified form aligned with the plunger and the detent ball. In practice, however, the engagement area element 28 has already rotated further; during further rotation, the engagement recess 29 has pushed the detent ball 11 back into the position shown in Fig. 6. In this respect, Fig. 6 is a simplified theoretical representation of the disengaged state which shows the engagement area (simplified) in an incorrect rotational position.

[0068] 5, a further threaded pin 32 can be seen in a further pin bore 33 in the coupling element 2, because the section is in a different section plane than the section in Fig. 4. The threaded pin 32 has a conical tip. It is used to assemble and secure the position of a guide bushing 34, which has a V-shaped circumferential groove on its outer surface. The tip of the threaded pin 32 is screwed into the V-shaped groove and thus fixes the position of the guide bushing 34, which serves to guide the locking ball 11 and also to guide a front cylindrical end (front end 17) of the plunger 9. For this purpose, the guide bushing 34 is provided with a first cylindrical inner surface 35, which forms the guide for the locking ball 11. A second cylindrical inner surface 36 forms the guide for the front end 17 of the plunger 9 .In this example, the locking ball 11 has a larger diameter than the front end 17 of the plunger 9. The two cylindrical inner surfaces 35 and 36 of the guide bushing 34 are adapted to the two aforementioned diameters. Between the cylindrical inner surfaces 35 and 36, the guide bushing 34 has the conical inner surface 37, which serves as a stop to limit the movement of the locking ball 11.

[0069] The coupling element 2 has a larger diameter than the coupling element 3 and it accommodates a shaft sealing ring 38 (shaft seal) which comprises a sealing lip 39 which bears against the coupling element 3. The shaft sealing ring 38 is arranged in such a way that the ingress of dirt into the guide bush 34 and the engagement area 12 is counteracted. The sectional view in Fig. 5 shows two transmission balls 15 which are each in contact with a stationary pressure body which is designed in annular form as a pressure ring 40. In addition, an axially movable pressure body is provided which is designed as a movable pressure ring 41. Finally, the tappet 9 has a shoulder element 14 which is designed in annular form as a shoulder ring. The shoulder ring comprises two functional surfaces.

[0070] A first functional surface 42 is an inclined surface formed as a circumferential groove 42a. The groove is designed such that its cross-section conforms to the shape or radius of the transmission balls 15. A second functional surface 16a of the shoulder element 14 is formed by a cylindrical rest surface 16, which in the present example, as in the prior art, is arranged parallel to the axial direction of the tappet 9.

[0071] Furthermore, Fig. 5 shows the spring device 22, which comprises six disc springs which are combined to form the disc spring assembly 23. In the coupled state shown, the disc spring assembly 23 is in a slightly preloaded state. On the end face 10c of the housing 10, a housing opening is provided with a closure element 43, which serves as a counterbearing for the disc spring assembly 23 and comprises one of the bearing openings for the tappet, which is provided with the seal S2. The closure element 43 is designed to be able to set a preload of the disc spring assembly 23 or to remove preload. For this purpose, a cylindrical inner wall 44 of the housing 10 is provided with an internal thread 45 and the closure element 43 has a cooperating external thread 46.The closure element 43 can be screwed into the housing 10 and preloaded more or less strongly against the disc spring assembly 23 or left unloaded. To secure the desired setting, the cylindrical surface of the closure element 43 provided with the external thread 46 is provided with a pocket, simply a radial blind bore 47, into which a soft material, e.g. an aluminum spacer 48, is embedded. The soft material has no threads, but comes into contact with the internal thread 45 of the housing 10 during assembly and is deformed in the process. The deformed spacer 48 serves to secure the set position of the closure element 43. The deformed spacer 48 achieves a stopping effect, like the embedded plastic of a self-locking hexagon nut DIN 985.

[0072] The spring force of the disc spring assembly 23 acts on the transmission ball 15 via two deflection components, namely the static pressure ring 40 and the movable pressure ring 41. The latter, in turn, deflect a component of the spring force into the annular shoulder element 14 of the plunger 9. The plunger 9 is thereby subjected to a force component that preloads it toward the engagement area 12.

[0073] In Fig. 6, which shows the safety element in a separated state of the coupling, the plunger 9 has retreated from the engagement area 12, whereby the transmission balls 15 have been moved radially outwards beyond the first functional surface 42. Now the transmission balls 15a rest on the second functional surface, i.e. on the action surface 49, which is inclined at an angle a of 7.5° relative to the central axis of the plunger 9.

[0074] The spring force emanating from the disc spring assembly 23 continues to press against the movable thrust ring 41, which acts on the transmission balls 15a and imparts a radially inward movement component. The transmission balls 15a, in turn, deflect via the inclined action surface into the plunger and impart an axial movement component in an advancing direction, whereby the plunger 9 presses the detent ball 11 toward the engagement area 12.

[0075] In contrast to the prior art, in the disengaged state the inclined action surface 49 immediately redirects a force component and generates an advancing movement into the plunger 9 via the transmission balls 15a.

[0076] Due to the flat inclination of the action surface 49 (acute angle α), the spring force is translated at the action surface. The translation is selected such that there is a defined limitation of the force component which advances the plunger 9 in its axial direction. The intention is thus to allow the engagement of the locking balls 11 in the engagement areas 12 in a material-friendly manner. The force component is dimensioned so small that engagement is preferably only possible with a small speed difference. With a larger speed difference, a greater advancing force in the plunger 9 would be necessary, but this would be accompanied by greater material wear, which the invention aims to prevent.On the one hand, the low advancing axial force reduces wear immediately after a malfunction, when coupling elements 2 and 3 are still in the final stages of rotation and are subject to material-wearing frictional contact due to a still-existing speed difference. On the other hand, subsequent commissioning can also be carried out in a material-protecting manner.

[0077] In the first case, when clutch 1 has disengaged in a torque-dependent manner during full operation, clutch elements 2 and 3 are initially still rotating, whereby a certain speed difference can quickly develop. Then, detent balls 11 and engagement areas 12 overtake each other while moving at different speeds, and this certain frictional contact causes material wear. However, because the tappets 9 and detent balls 11 are subjected to a defined, small, advancing axial force component according to the invention, wear can be kept to a minimum during this operating phase.

[0078] During recommissioning, it is recommended that, starting from a standstill of both coupling elements 2 and 3, the driving coupling element 2 or 3 should only start up slowly in order to use the defined, low advancing force acting on the tappet 9 to gently press the detent balls 11 into engagement with the engagement areas 12 of the coupling element 3. If, on the other hand, the driving coupling element accelerates too sharply, engagement may not be successful and will therefore not occur in practice. The only functioning method of engagement is necessarily material-friendly with the proposed safety element.

[0079] Fig. 7 shows a design of an alternative grooved tappet 9b, which can replace a tappet 9 of the first embodiment shown and then results in a further embodiment of the safety element 5a according to the invention. The grooved tappet 9b has a cylindrical shaft and an annular shoulder element (shoulder ring 14b) with two functional surfaces based on those functional surfaces of the first embodiment according to Figures 5 and 6. Their tappet 9 has a shoulder element 14 with two functional surfaces. The first functional surface is an inclined surface, which is formed as a circumferential groove 42a. The second functional surface is the action surface 49, which has an inclination with respect to the axial direction (central axis) of the tappet 9. Just like the first embodiment, a safety element 5a provided with the grooved tappet 9b has a self-resetting function.Due to the self-returning action, the grooved plunger 9b, when in the disengaged state, is subjected to an axial force that advances it toward its position for the engaged state, as shown in Fig. 5.

[0080] According to Fig. 7, additional radial grooves 53 are provided which extend over both functional surfaces, with the second functional surface being arranged in the region of the action surface 49 (conical outer surface). Because only the grooves 53 interact with the transmission bodies, in the present example the groove surface of each groove 53 serves as a replacement for the truncated conical action surface 49. Advantageously, the grooves 53 have the same inclination as the conical outer surface, which forms the action surface 49 in Fig. 5. In the assembled state, the radial grooves 53 in Fig. 7 act as a guide for the respective transmission body 15, preferably rolling elements. In the present example, the proposed transmission balls 15a are provided as the transmission bodies. The cross-sections of the radial grooves 53 are adapted to the shape of the transmission balls 15a, like the raceways of a rolling bearing.

[0081] An important aspect of this embodiment is again to reduce the surface pressure between the transmission bodies 15 and the grooves 53 of the shoulder ring 14b. This is achieved by adapting the cross-sections of the radial grooves 53, as mentioned, to the cross-sections of the transmission bodies 15, such as the transmission balls 15a proposed here. The grooves 53 form a wear-reducing means that has a positive effect on the service life of the safety element.

[0082] A further advantage is also apparent here when the safety element 5a is switched between the engaged and disengaged state. In the first exemplary embodiment, this can result in adjacent transmission balls 15a changing their distance from one another. Generally, in all exemplary embodiments, the distance between the transmission balls 15a is greatest in the disengaged state. Without lateral guidance by grooves 53, transmission balls 15a can, under certain circumstances and disadvantageously, move towards or away from one another in the circumferential direction. This can be avoided by means of guidance by the proposed radial grooves 53 in Fig. 7.

[0083] With reference to Fig. 8, a further measure is proposed which concerns a modified axially movable pressure body and contributes to a means of wear reduction. The movable pressure body can replace the movable pressure body 41 of the first embodiment shown or it can be used, for example, in a safety element 5a in combination with the grooved tappet 9a. The axially movable pressure body is annular in design as a pressure ring 41a and has wear-reducing radial grooves 51, the cross section of which is also adapted to the shape of the transmission bodies 15, here transmission balls 15a. In the grooves 51, the surface pressure relative to the transmission body 15 is again reduced and the means of wear reduction is thus provided.In order to be able to combine the pressure ring 41a with the grooved tappet 9b, the pressure ring has radial grooves 51 in a congruent arrangement, so that in pairs one groove 53 of the grooved tappet 9b and one groove 51 of the pressure ring can act as a common guide for the transmission body 15.

[0084] With reference to Fig. 9, a further measure is proposed which concerns a modified static pressure body. The static pressure body can replace the static pressure body 40 of the first exemplary embodiment or it can be used in a safety element 5a in combination with the grooved tappet 9b according to Fig. 7 and / or with the movable pressure ring 41a according to Fig. 8. The static pressure body of Fig. 9 is annular in design as a pressure ring 40a and has radial grooves 52, the cross section of which is also adapted to the shape of the transmission bodies 15, here again the transmission balls 15a. For a combination with the grooved tappet 9b and / or with the pressure ring 41a of Fig. 8, the pressure ring 40a also has the radial grooves 52 in a congruent arrangement. Thus, in pairs, one groove 53 of the grooved tappet 9b and / or one groove 51 of the movable pressure ring can interact with one groove 52 of the static pressure ring 40a.This results in common guides for the transmission bodies 15 .

[0085] Ju- f 1 11 . September 2024

[0086] Applicant:

[0087] MA T. Malmedie Antriebstechnik GmbH

[0088] 42653 Solingen

[0089] Self-resetting safety element and coupling comprising several of these safety elements

[0090] List of reference symbols

[0091] 1 clutch

[0092] 2 coupling element

[0093] 3 Coupling element

[0094] 4 rotation axis

[0095] 5a Security element

[0096] 5b Security element

[0097] 6a Central axis

[0098] 7 mounting level

[0099] 8 mounting level

[0100] 9 plungers

[0101] 9b Grooved tappet

[0102] 10 housings

[0103] 10a Housing edge

[0104] 10b front side

[0105] 10c Front side (with housing opening)

[0106] 11 locking ball

[0107] 12 Snap-in area

[0108] 13 Adjusting screw

[0109] 14 shoulder element

[0110] 14a Shoulder ring 14b Shoulder ring

[0111] 15 transfer bodies

[0112] 15a Transmission ball

[0113] 16 cyl. rest area

[0114] 16a second functional area

[0115] 17 Pin end (plunger)

[0116] 18 Fastening and adjustment devices

[0117] 19 external threads

[0118] 20 cyl. side wall (housing)

[0119] 21 internal thread

[0120] 22 Spring device

[0121] 23 Disc spring element

[0122] 24 remedies

[0123] 25 threaded pin

[0124] 26 Hole

[0125] 27 Intermediate piece

[0126] 28 Snap-in area element

[0127] 29 Snap-in recess

[0128] 30 interior surface

[0129] 31 protruding collar

[0130] 32 threaded pin

[0131] 33 pin hole

[0132] 34 Guide bushing

[0133] 35 cyl. inner surface

[0134] 36 cyl. inner surface

[0135] 37 conical inner surface

[0136] 38 Shaft seal

[0137] 39 Sealing lip

[0138] 40 Pressure ring (stationary)

[0139] 40a Pressure ring (stationary)

[0140] 41 Pressure ring (movable)

[0141] 41a Pressure ring (movable)

[0142] 42 first functional area

[0143] 42a Concave groove 43 Closure element

[0144] 44 cyl. inner wall

[0145] 45 internal thread (housing 10)

[0146] 46 External thread (closing element) 47 Blind hole

[0147] 48 intermediate piece (aluminum)

[0148] 49 action area

[0149] 51 groove

[0150] 52 groove 53 groove

[0151] LI warehouse opening

[0152] L2 bearing opening

[0153] SI sealing ring S2 sealing ring

Claims

Self-resetting safety element and coupling comprising several of these safety elements Patent claims 1. Safety element (5a) with self-resetting properties for a clutch (1) comprising two clutch elements (2, 3), wherein in a coupled state a torque can be transmitted between the two clutch elements (2, 3), and wherein by means of the safety element the two clutch elements (2, 3) can be switched into a disengaged state as a function of the torque and can be automatically reset to the engaged state, with the proviso that the self-resetting safety element (5a) comprises: a plunger (9, 9b) which is displaceable in its axial direction by means of a provided bearing (LI, L2) in order to provide the engaged state or the disengaged state of the clutch (1) in the assembled state, a locking element (11) which bears against the plunger (9, 9b), a spring device (23) by means of which a spring force can be transmitted into the plunger (9, 9b) and further into the locking element (11), wherein the plunger (9, 9b) is provided with a shoulder element (14) which protrudes in the radial direction on the tappet (9, 9b), wherein at least one transmission body (15, 15a) is provided which cooperates on the one hand with the shoulder element (14) and furthermore with at least one pressure body (40, 41, 40a, 41a), for which the pressure body (40, 41, 40a, 41a) has a deflection surface and the shoulder element (14) comprises two functional surfaces (16a, 42), namely an inclined surface (42a) and a laterally arranged rest surface (16), wherein the transmission body (15, 15a) in the engaged state of the clutch (1) is in contact with the inclined surface (42a) of the shoulder element (14) in a manner transmitting the spring force, while in the disengaged state of the clutch (1) it rests on the lateral rest surface (16) of the shoulder element (14) and with the further proviso that in the assembled state the plunger (9, 9b) and the locking element (11) are assigned to a first of the two coupling elements (2) of the coupling (1),and that the other second coupling element (3) is assigned a latching area (12) which is designed complementarily to the latching element (11), characterized in that the, Rest surface (16) of the shoulder element (14) of the tappet (9, 9b) is further developed into an action surface (49) which has an inclination relative to the axial direction of the tappet (9, 9b), namely is inclined by an angle (a) with respect to the axial direction of the tappet (9, 9b).

2. Security element (5a) according to claim 1, characterized in that the angle (a) of the inclination of the rest surface (16) of the shoulder element (14) is in a range of 3° to 12°, preferably in a range of 5° to 10° and particularly preferably in a range of 7° to 8°.

3. Safety element (5a) according to claim 1 or 2, characterized in that a first axially movable pressure body (41, 41a) and a second pressure body (40, 40a) are provided, and that the second pressure body (40, 40a) is arranged stationary relative to the housing (10).

4. Safety element (5a) according to claim 3, characterized in that both pressure bodies (40, 41, 40a, 41a) are spring-loaded, that at least one of the two pressure bodies (40, 41, 40a, 41a) has an inclined deflection surface, that each of the deflection surfaces is in contact with the transmission body (15, 15a), and that at least the deflection surface of one of the two pressure bodies (41, 41a) is arranged inclined at an angle to a radial plane.

5. Security element (5a) according to one of claims 1 to 4, characterized in that the bearing (LI, L2) of the tappet (9, 9b) is integrated into the housing (10), and that the housing (10) has a fastening means (18) which is prepared for the purpose of simple assembly of the safety element (5a) on a coupling element (2).

6. Security element (5a) according to one of claims 1 to 5, characterized in that the housing (10) is provided with an adjusting means (18) by means of which, in the assembled state, its axial position relative to the supporting coupling element (2) can be adjusted.

7. Security element (5a) according to one of claims 1 to 6, characterized in that the latching area (12) is designed as an exchangeable latching area element (28) which has a fixed positioning aid (31), wherein the positioning aid (31) interacts with a stop means of the relevant coupling element (3) in the mounted state.

8. Security element (5a) according to one of claims 1 to 7, characterized in that a guide bush (34) is assigned which, in the assembled state, serves to guide the tappet (9, 9b) and / or to guide the locking element (11), wherein the guide bush (34) is also assigned to the first coupling element (2) concentrically to the tappet (9, 9b).

9. Safety element (5a) according to claim 8, characterized in that the guide bush (34) is assigned as a separate component or is assigned as an integral part of the safety element (5a), for example is assigned to a housing part (10).

10. Security element (5a) according to one of claims 5 to 9, characterized in that the housing (10) has a closure element (43) as a housing part, that the closure element (43) acts as a counter bearing for the spring device (23) and / or as a guide for the plunger (9, 9b) and / or the locking element (11).

11. Safety element (5a) according to claim 5 to 10, characterized in that the closure element (43) comprises a means by means of which its axial position relative to the housing (10) can be adjusted.

12. Security element (5a) according to one of claims 1 to 11, characterized in that the spring device comprises at least one disc spring, preferably a disc spring package (23) consisting of several disc springs.

13. Security element (5a) according to one of claims 1 to 12, characterized in that the plunger (9, 9b) and / or at least one of the pressure bodies is provided on its deflection surface with at least one radially extending groove (51, 52) which, in the assembled state, acts as a guide for the transmission body (15, 15a).

14. Security element (5a) according to one of claims 1 to 13, characterized in that the locking element (11) and / or the locking area element (28) is made of a ceramic material.

15. Security element (5a) according to one of claims 1 to 14, characterized in that the pressure body (40, 41, 40a, 41a) and / or the transmission supply body (15, 15a) is made of a ceramic material.

16. Safety element (5a) according to one of claims 1 to 15, characterized in that the plunger (9, 9b) is composed of a plunger shaft and a shoulder element connectable thereto.

17. Coupling (1) comprising two coupling elements (2, 3) which are rotatable about an axis (4) and which can be switched into a coupled state and a disengaged state, wherein a torque can be transmitted in the coupled state, wherein on one of the coupling elements (2, 3) on a defined diameter and concentric to the axis of rotation (4) of the coupling element (2, 3) a plurality of safety elements (5a) according to one of claims 1 to 16 are arranged, and wherein on the second coupling element (2) on an identical diameter and concentric to its axis of rotation (4) a corresponding number of latching area elements (28) are arranged, namely at congruent distances as the safety elements (5a).

18. Coupling (1) according to claim 17, characterized in that a circumferential groove is provided on the second coupling element (3), which cooperates with the locking elements (11) of the safety elements (5a) in the uncoupled state.

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