DE102023126979A1 - Self-resetting safety element and coupling comprising several of these safety elements - Google Patents

Abstract

The invention relates to a 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 and automatically reset to the engaged state in a torque-dependent manner.
The invention also relates to a coupling comprising at least one safety element (5a) according to the invention.

Description

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. The invention also relates to a coupling comprising several safety elements according to the invention, in particular a torque-dependently switchable shaft coupling.

The safety element is designed for a coupling comprising two coupling elements, which can be considered as coupling halves. In the case of a shaft coupling, a torque can be transmitted between the two coupling elements when engaged, whereby the safety element is torque-dependent, i.e. When a defined torque is exceeded, the two coupling elements can be automatically switched to the disengaged state, with the proviso that the safety element comprises: a plunger which can be displaced 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 which 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 plunger and further into the locking element, for example a disc spring assembly, wherein the plunger is provided with a shoulder element which protrudes in the radial direction from the plunger, 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 further with at least one pressure body and cooperates therewith, wherein the transmission body is, for example, a rolling body and the pressure body is preferably designed as a circumferential annular pressure body is designed, for which the pressure body has a deflection surface and the shoulder element comprises two functional surfaces, namely an inclined surface also pointing 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 to transmit the spring force, while in the disengaged state of the coupling (neutral) it bears against the lateral rest 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 the other second coupling element is assigned a locking area, 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.

Safety elements of this type, as well as couplings equipped with them, are used in heavy-duty machinery, for example, in mining, the construction industry, or in material handling systems, such as cranes, such as container cranes. For example, a container crane in a modern port terminal faces special requirements due to increasing automation.

Safety elements are also known which, if they are in the disengaged position and the coupling elements are separated after a malfunction, cannot automatically return to the engaged state. With this type of safety element, the reset must be achieved manually, which is labor-intensive and always requires an operator on site. An example of this is the 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 torque to the other coupling half by spring force in an advanced position. After a malfunction, 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 device is interrupted or neutralized. In order to switch the coupling back to torque-transmitting operation, the transmission of spring force to the plunger must be restored and the neutralization must be canceled. With the aforementioned state of the art, this switching can only be brought about by manual intervention, which can be achieved, for example, by a targeted hammer blow and requires operating personnel.

The applicant has disclosed a generic security element which has a self-resetting function in the DE 10 2019 110 297 B3 This safety element or a coupling equipped with it allows re-engaging after a fault has occurred, when the coupling halves are separated, without the need for an operator to manually activate each safety element. This state of the art provides a mechanism that has a The actuating lever is pivotable against the plunger by spring force to achieve a return to the engaged state. The present application now pursues another improved solution to this problem.

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.

According to the invention, the object is achieved in that the rest surface of the shoulder element of the plunger is further developed into an action surface which has an inclination relative to the axial direction of the plunger, namely is inclined by an angle α with respect to the axial direction of the plunger.

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

The appropriate degree of inclination of the action surface can be determined empirically. It is advisable to only return the locking elements to the engagement areas when the speed difference between the coupling halves is small, because this allows for re-engagement with a low return force on the plunger in a material-friendly manner.

Even if the transmission body 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 pressure elements. This involves a combination of rolling and sliding.

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.

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 capacity 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 retreat 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.

The security element of the US 2010/0224713 A1 and the DE 10 2019 110 297 B3 The rest surface is provided on the shoulder element of the plunger. When the transmission bodies (balls) are in contact with 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 the US 2010/0224713 A1 as well as that of the DE 10 2019 110 297 B3 require a high level of effort, either in terms of personnel or equipment, to act on the ram from the outside.

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 conveniently 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 α of their inclination. By varying the angle of inclination α, the transmission ratio of the action surface can be adjusted. The desired effect is to direct a relatively low axial force into the plunger and allow it to advance towards its engaged position. The transmission ratio is advantageously such that the locking elements can only be moved back into the engagement areas when the speed The difference between the clutch halves is small. Re-engagement should only be permitted with a significantly reduced return force on the tappet.

As a result, a clutch equipped with safety elements according to the invention can now be automatically re-engaged in the event of a malfunction that has led to disengagement and an interruption in torque transmission, simply by slowly restarting the driving clutch element. Before re-engaging, it is always advisable to eliminate the problem that is responsible for the torque being exceeded. It is advisable to only then slowly start the clutch up again in order to automatically re-engage. The driving clutch element is rotated 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 transmission again.

The gear ratio, adjusted by adjusting the inclination of the action surface, is specifically selected so that re-engagement of the locking element is only possible at a defined, small speed difference. This process is therefore gentle on the material. As mentioned above, it is advisable to first bring the clutch to a complete standstill, and then, before restarting the clutch, identify and eliminate the cause of the torque overshoot.

A clutch equipped with the proposed safety element can thus be advantageously 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 required for the plunger, which is small due to the gear ratio, is sufficient to move it to its advanced, engaged position. The clutch can then transmit the torque for which it is designed.

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

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.

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

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 to 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.

The housing is expediently provided with an adjustment means by means of which, when assembled, its axial position relative to the supporting coupling element can be adjusted. For the proposed safety element, it is considered important to enable adjustability of the axial position of several components that are arranged in a row when assembled. The components in question are the plunger, the locking element, and the engagement 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 engagement 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.

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 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 locking area being designed as an exchangeable locking area element, which fixed positioning aid, wherein the positioning aid interacts with a stop means of the respective coupling element when mounted.

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.

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.

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

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 as a guide for the plunger and/or the locking element.

The closure element expediently comprises a means by which its axial position relative to the housing can be adjusted. The closure element is simply provided with a guide bore for the plunger and has a rim with an external thread. The external thread can serve as a means of fastening. Furthermore, the external thread can form the aforementioned means for adjusting the axial position. The external thread of the closure element expediently cooperates with a matching internal thread provided in the housing, preferably a fine-pitch thread. Furthermore, an integrated locking element can be provided, e.g., an aluminum piece embedded in a blind bore arranged transversely to the external thread in the area of the external thread. The aluminum piece extends into the area of the external thread and is only deformed when the external thread is screwed into the internal thread of the housing, achieving a locking effect, similar to the embedded plastic of a self-locking hexagon nut DIN 985, which deforms during screwing and acts as a threadlocker.

The spring device may comprise at least one disc spring; preferably, a disc spring assembly consisting of several disc springs is provided.

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.

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

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

The static or stationary pressure body and the movable pressure body can alternatively be made of 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 of a metal alloy and subjected to a treatment to improve wear resistance. The treatment for the aforementioned components can be a heat treatment, for example to harden pressure bodies and/or transmission bodies made of steel, or it can be a treatment in the form of a coating that applies a material that improves wear properties, for example a coating with chromium, in particular a hard chromium layer.

Furthermore, it is advisable for the components within the housing to be operated in the presence of a suitable lubricant.

For the tappet, it is further proposed that it be composed of several parts, comprising at least one tappet shaft and a shoulder element connectable thereto, 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 establishes a defined, fixed relationship between the tappet shaft and the shoulder ring, particularly in the axial direction. The two-piece design has the advantage of allowing the shoulder ring to 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 fitted with a new shoulder ring. This also makes it possible to subject the shoulder ring to a targeted treatment that improves its wear properties. improved and to leave the tappet shaft untreated or to subject it to another suitable treatment.

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

Advantageously, a circumferential groove is provided on the second coupling element, which interacts with the locking elements of the safety elements when disengaged. The cross-section of the groove is suitably adapted to the cross-section of the locking element, for example, to the cross-section of a spherical locking element.

• 1 eine Kupplung versehen mit sechs erfindungsgemäßen Sicherheitselementen,
• 2 eine ausschnittsweise Schnittdarstellung eines Sicherheitselements nach dem Stand der Technik montiert an einer Kupplung und dargestellt im eingekuppelten Zustand,
• 3 eine ausschnittsweise Schnittdarstellung des bekannten Sicherheitselements der 2 in einem fiktiven getrennten Zustand der Kupplung,
• 4 eine ausschnittsweise Schnittdarstellung eines ersten Ausführungsbeispiels des erfindungsgemäßen Sicherheitselements montiert an einer Kupplung und dargestellt im eingekuppelten Zustand,
• 5 eine ausschnittsweise Schnittdarstellung des Ausführungsbeispiels der 4 in einer anderen Schnittebene im eingekuppelten Zustand,
• 6 eine ausschnittsweise Schnittdarstellung des Ausführungsbeispiels der 4 und 5 in einem getrennten Zustand der Kupplung,
• 7 eine perspektivische Darstellung eines alternativen Stößels für eine zweite Ausführungsform des erfindungsgemäßen Sicherheitselements,
• 8 eine perspektivische Darstellung eines alternativen beweglichen Druckkörpers für die zweite Ausführungsform des erfindungsgemäßen Sicherheitselements,
• 9 eine perspektivische Darstellung eines alternativen stationären Druckkörpers für die zweite Ausführungsform des erfindungsgemäßen Sicherheitselements.

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

• 1 a coupling provided with six safety elements according to the invention,
• 2 a partial sectional view of a safety element according to the state of the art mounted on a coupling and shown in the engaged state,
• 3 a partial sectional view of the known security element of the 2 in a fictitious separated state of the clutch,
• 4 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,
• 5 a partial sectional view of the embodiment of the 4 in another cutting plane in the coupled state,
• 6 a partial sectional view of the embodiment of the 4 and 5 in a separated state of the clutch,
• 7 a perspective view of an alternative plunger for a second embodiment of the security element according to the invention,
• 8 a perspective view of an alternative movable pressure body for the second embodiment of the security element according to the invention,
• 9 a perspective view of an alternative stationary pressure body for the second embodiment of the security element according to the invention.

In 1 A clutch 1 according to the invention is shown, 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 are rotatable 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.

The coupling 1 is intended, for example, for the drive trains of machines such as those used in mining, the construction industry, or in material handling systems such as cranes. In particular, it is intended for use in container cranes. Sudden overloads can occur in such machines, endangering machine components such as motors, gearboxes, etc. To protect these components, the proposed coupling 1 separates the power transmission between the two coupling elements 2 and 3, thus keeping overloads away from the aforementioned machine components and protecting them. The coupling 1 can therefore be referred to as a safety coupling or overload coupling.

To enable clutch 1 to fulfill its torque-dependent safety function, it is equipped 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 transmission capacity of a single safety element 5a.

The safety elements 5a are subject to wear. Certain components of the safety element 5a that are critical for operational safety are usually inspected regularly and replaced if necessary.

In order to improve the service life of the safety element 5a according to the invention, they are provided with means for reducing wear, as follows below.

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 rotational axis 4 of the coupling 1. Each safety element 5a is rotationally symmetrical and has a central axis 6a. It is positioned with the central axis 6a on the pitch circle of the coupling element 2. In the present example, the central axes 6a of the safety elements 5a are arranged parallel to the rotational axis 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, to obtain a coupling that acts in the axial direction.

The 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 rotation axis 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 according to 2 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. In 3 The disengaged state of the safety element 5b is shown, in which a cylindrical rest surface 16 as part of the shoulder element 14 has contacted the transmission bodies 15. In this position, the transmission of a spring preload into the plunger 9 is neutralized. In order to switch from the disengaged state back to the engaged state, the plunger 9 must be advanced from the outside, thereby pushing the locking ball 11 back into the engagement area 12.

4 shows a first 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 clutch equipped with this function, this means that it can be automatically switched from a separated state of the clutch halves to the engaged state. For the sake of simplicity, the same reference numerals are used for comparable features as previously described.

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, 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 4 presses a front end 17 of the plunger against a spherical locking element (locking ball 11), wherein the plunger 9 is 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 safety element 5a corresponds to the structure of the known safety element according to 2 and 3 at least largely agree. In contrast to this prior art, however, the safety element dispenses with a housing edge as a mounting plane for fixed positioning on the respective coupling element 2, and the plunger 9 otherwise differs by the above-mentioned inclined action surface 49.

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 is arranged in each of the bearing openings. The fastening and adjustment means 18 is simply 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. The coupling element 2 is provided with a complementary internal thread 21 into which the external thread 19 of the housing 10 can be screwed. The screw connection consisting of the external thread 19 and the internal thread 21 has a dual function. On the one hand, it serves for assembly and fastening, and on the other hand, it provides the aforementioned axial adjustability. The axial position of the housing 10 determines the axial position of the plunger 9, which is arranged in a row with the locking ball 11 and in 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. The desired result is a play-free connection between the plunger 9 and the locking ball 11 and, subsequently, a play-free connection between the locking ball 11 and the engagement area 12.

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 which is arranged coaxially around the plunger 9.

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, to ensure that play is only eliminated once the machine has warmed up and reached its intended operating state. A certain amount of 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 rotate the housing 10 back in the opposite direction by a defined angle, thus creating a defined play.

The final screw-in depth of the housing 10 in the coupling element 2 is suitably secured. A suitable means 24 is provided for securing, as in the example of 4 a threaded pin 25 arranged in a bore 26 of 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. This intermediate piece 27 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.

The engagement 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 engagement areas 12 are each designed as an exchangeable engagement area element 28. The engagement area element 28 has an external thread that is screwed into an internal thread of the coupling element 3. Each engagement area element 28 has an engagement recess 29, here a recess with a conical inner surface 30. Furthermore, each engagement 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 engagement 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 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.

The 5 as well as 6 refer to how 4 , to the first embodiment of the security 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, which has an inclination relative to the axial direction of the plunger 9. In the present example, the action surface is inclined by an angle α of 7.5° relative to the axial direction of the plunger 9. In the example, the action surface 49 is arranged circumferentially on a shoulder ring 14a. This results in a frustoconical shape of the action surface 49.

Compared to 4 show the 5 and 6 the first embodiment in a different sectional plane, where 5 refers to the engaged state and 6 shows the disengaged state, in which the plunger 9 and the locking ball 11 assume a retracted position; the coupling is separated. The locking ball has retracted from the engagement area. In 6 The locking area element 28 is shown in simplified form aligned with the plunger and the locking ball. In practice, however, the locking area element 28 has already rotated further; during the further rotation hens, the locking recess 29 has pushed the locking ball 11 back into the 6 shown position. In this respect, 6 a simplified theoretical representation of the disengaged state, showing the engagement area (simplified) at an incorrect rotational position.

Furthermore, in the section plane of the 5 another threaded pin 32 in another pin hole 33 in the coupling element 2 can be seen, because the section is in a different cutting plane than the section in 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 detent ball 11 as well as 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 detent ball 11. A second cylindrical inner surface 36 forms the guide for the front front end 17 of the plunger 9. In this example, the detent ball 11 has a larger diameter than the front 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 bush 34 has the conical inner surface 37, which serves as a stop to limit the movement of the locking ball 11.

The coupling element 2 has a larger diameter than the coupling element 3 and accommodates a shaft seal 38 (shaft seal) comprising a sealing lip 39 that bears against the coupling element 3. The shaft seal 38 is arranged to prevent the ingress of dirt into the guide bushing 34 and the engagement area 12.

In the sectional view of the 5 Two transmission balls 15 are shown, each in contact with a stationary pressure body, which is designed as a ring-shaped pressure ring 40. In addition, an axially movable pressure body is provided, designed as a movable pressure ring 41. Finally, the tappet 9 has a shoulder element 14, which is designed as a ring-shaped shoulder ring. The shoulder ring comprises two functional surfaces. A first functional surface 42 is an inclined surface, which is designed as a circumferential groove 42a. The groove is designed such that its cross-section adapts 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.

Furthermore, 5 the spring device 22, which comprises six disc springs that 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 encompasses 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 adjust the 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. Thus, the closure element 43 can be screwed into the housing 10 and can be preloaded more or less strongly against the disc spring assembly 23, or it can be left unloaded. To secure the desired setting, the cylindrical surface of the locking element 43, which is 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 locking element 43. The deformed spacer 48 achieves a stopping effect, similar to the embedded plastic of a self-locking hexagon nut DIN 985.

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.

In 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 lie on the second functional surface, ie on the action surface 49, which is at an angle α of 7.5° relative to the central axis of the tappet 9.

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 the advancing direction, whereby the plunger 9 presses the detent ball 11 toward the engagement area 12.

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.

Due to the flat inclination of the action surface 49 (acute angle α), the spring force is transmitted at the action surface. The transmission is selected such that a defined limitation of the force component occurs, which advances the plunger 9 in its axial direction. The intention is to thus allow the engagement of the locking balls 11 into the engagement areas 12 in a material-saving 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 larger advancing force in the plunger 9 would be required, which would, however, be accompanied by greater material wear, which the invention aims to prevent. On the one hand, the small advancing axial force reduces wear immediately after a malfunction, when the coupling elements 2 and 3 are still in the decaying rotation and are subject to material-wearing frictional contact due to a still existing speed difference. On the other hand, later commissioning can also be carried out in a material-saving manner.

In the first case, when clutch 1 has disengaged torque-dependently 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 plungers 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.

During recommissioning, it is recommended to start the driving coupling element 2 or 3 slowly, starting from a standstill of both coupling elements 2 and 3, in order to use the defined, low advancing force applied to the plunger 9 to gently press the detent balls 11 into engagement with the engagement areas 12 of the coupling element 3. If, however, the driving coupling element accelerates too rapidly, engagement may not be successful and will therefore not occur in practice. The only effective method of engagement with the proposed safety element is necessarily material-friendly.

7 showed a design of an alternative grooved plunger 9b, which can replace the plunger 9 of the first illustrated embodiment and then results in a further embodiment of the security element 5a according to the invention. The grooved plunger 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 the 5 and 6 . Its plunger 9 has a shoulder element 14 with two functional surfaces. The first functional surface is an inclined surface formed as a circumferential groove 42a. The second functional surface is the action surface 49, which has an inclination relative to the axial direction (center axis) of the plunger 9. Just as in the first embodiment, a safety element 5a provided with the grooved plunger 9b has a self-resetting function. Due to the self-resetting, the grooved plunger 9b, when it has entered the disengaged state, is subjected to an axial force that advances it towards its position for the engaged state, as shown in 5 .

According to 7 Additional radial grooves 53 are provided, which extend over both functional surfaces, with the second functional surface being arranged in the area of the action surface 49 (conical outer surface). Because only the grooves 53 interact with the transmission body, in the present example the groove surface of each groove 53 serves as a replacement for the frustoconical action surface 49. Advantageously, the grooves 53 have the same inclination as the conical outer surface, which in 5 forms the action surface 49. In the assembled state, the radial grooves 53 act in 7 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.

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.

A further advantage is also apparent here when the safety element 5a is switched between the engaged and disengaged states. In the first embodiment, this can be accompanied by neighboring transmission balls 15a changing their distance from one another. Generally, in all 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. By means of guidance by the proposed radial grooves 53 of the 7 this can be avoided.

Based on 8 A further measure is proposed which relates to 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 illustrated embodiment 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 annularly designed 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, thus providing the means of wear reduction. 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.

Based on 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 embodiment or it can be used in a safety element 5a in combination with the grooved tappet 9b according to 7 and or with the movable pressure ring 41a according to 8 The static pressure hull of the 9 is designed as a ring-shaped 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 the 8 The thrust ring 40a also has the radial grooves 52 in a congruent arrangement. Thus, a groove 53 of the grooved tappet 9b and/or a groove 51 of the movable thrust ring can interact in pairs with a groove 52 of the static thrust ring 40a. This results in common guides for the transmission bodies 15.

List of reference symbols

1

coupling

2

coupling element

3

coupling element

4

axis of rotation

5a

Security element

5b

Security element

6a

central axis

7

Mounting level

8

Mounting level

9

pestle

9b

Grooved tappet

10

Housing

10a

Case edge

10b

front side

10c

Front side (with housing opening)

11

locking ball

12

Snap-in area

13

Adjusting screw

14

Shoulder element

14a

shoulder ring

14b

shoulder ring

15

transmission body

15a

transmission ball

16

cylindrical resting area

16a

second functional area

17

Pin end (plunger)

18

Fastening and adjustment devices

19

external thread

20

cylindrical side wall (housing)

21

internal thread

22

Spring device

23

Disc spring element

24

Medium

25

threaded pin

26

drilling

27

Intermediate piece

28

Snap-in area element

29

Snap-in recess

30

inner surface

31

protruding collar

32

threaded pin

33

pin hole

34

guide bushing

35

cylindrical inner surface

36

cylindrical inner surface

37

conical inner surface

38

shaft seal

39

sealing lip

40

Pressure ring (stationary)

40a

Pressure ring (stationary)

41

Pressure ring (movable)

41a

Pressure ring (movable)

42

first functional area

42a

cove

43

locking element

44

cylindrical inner wall

45

Internal thread (housing 10)

46

External thread (closing element)

47

blind hole

48

Intermediate piece (aluminum)

49

Action area

51

groove

52

groove

53

groove

L1

Warehouse opening

L2

Warehouse opening

S1

sealing ring

S2

sealing ring

QUOTES CONTAINED IN THE DESCRIPTION

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

• US 2010/0224713 A1 [0004, 0013]
• DE 10 2019 110 297 B3 [0005, 0013]

Claims (18)

A safety element (5a) with self-resetting properties for a clutch (1) comprising two clutch elements (2, 3), wherein in an engaged 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 can be displaced in its axial direction by means of a provided bearing (L1, 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 is transmitted up to the plunger (9, 9b) and further into the locking element (11). is transferable, - wherein the tappet (9, 9b) is provided with a shoulder element (14) which projects 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) to transmit the spring force, while in the disengaged state of the clutch (1) it is in contact with 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 locking region (12) which is designed to be complementary to the locking element (11), - characterized in that the rest surface (16) of the shoulder element (14) of the plunger (9, 9b) is further developed into an action surface (49) which has an inclination relative to the axial direction of the plunger (9, 9b), namely is inclined by an angle (α) with respect to the axial direction of the plunger (9, 9b). Safety element (5a) according to Claim 1 , characterized in that the angle (α) 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°. 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). 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. Safety element (5a) according to one of the Claims 1 until 4 , characterized in that the bearing (L1, L2) of the plunger (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 mounting of the safety element (5a) on a coupling element (2). Safety element (5a) according to one of the Claims 1 until 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. Safety element (5a) according to one of the Claims 1 until 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. Safety element (5a) according to one of the Claims 1 until 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). 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). Safety element (5a) according to one of the Claims 5 until 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 acts as a guide for the plunger (9, 9b) and/or the locking element (11). Safety element (5a) according to Claim 5 until 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. Safety element (5a) according to one of the Claims 1 until 11 , characterized in that the spring device comprises at least one disc spring, preferably a disc spring package (23) consisting of several disc springs. Safety element (5a) according to one of the Claims 1 until 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). Safety element (5a) according to one of the Claims 1 until 13 , characterized in that the locking element (11) and/or the locking area element (28) is made of a ceramic material. Safety element (5a) according to one of the Claims 1 until 14 , characterized in that the pressure body (40, 41, 40a, 41a) and/or the transmission body (15, 15a) is made of a ceramic material. Safety element (5a) according to one of the Claims 1 until 15 , characterized in that the tappet (9, 9b) is composed of a tappet shaft and a shoulder element connectable thereto. 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 in the coupled state a torque can be transmitted, wherein on one of the coupling elements (2, 3) on a defined diameter and concentrically to the rotational axis (4) of the coupling element (2, 3) several safety elements (5a) according to one of the Claims 1 until 16 are arranged, and wherein a corresponding number of latching area elements (28) are arranged on the second coupling element (2) on an identical diameter and concentrically to its axis of rotation (4), specifically at congruent distances as the safety elements (5a). Clutch (1) after Claim 17 , characterized in that a circumferential groove is provided on the second coupling element (3) which, in the uncoupled state, interacts with the locking elements (11) of the safety elements (5a).

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