DRIVE AND / OR ADJUSTING DEVICE WITH OVERLOAD PROTECTION

Description

[0001] The present invention relates to a drive and / or adjustment device for driving and / or adjusting a rotatable assembly, in particular a toothed large roller bearing ring of a wind turbine, a cable winch or a slewing gear of a construction machine, with an output element for the rotational drive of the rotatable assembly, a gear which is connected upstream of the output element and has at least one torque-transmitting gear, and an overload protection for the rotatable assembly.

[0002] Such a drive and / or adjustment device is disclosed in EP 3 483 477 A1, in which a safety clutch is provided between two coaxially arranged gears as overload protection. The gears are secured against rotation relative to each other via locking projections on the end faces and are preloaded against each other by a spring, so that in the event of an overload, they drift apart axially against the spring force and can slip. Further drive and / or adjustment devices with overload protection are disclosed in EP 1 561 970 A3 and WO 2008 / 019931 A1.

[0003] In large rotary drives or positioning systems subject to large external loads, such as the nacelle or blade pitch drives of wind turbines or the slewing gear of a crane such as a derrick crane or even powerful cable winches, gear rings are usually attached to the assemblies to be rotated. These gear rings can be rotationally driven or adjusted by a meshing drive pinion, which forms the output element of a drive train. An electric or hydraulic motor can be used as the drive, which drives the output element and thus the gear ring via a gearbox. The gear ring can be attached to the inner or outer circumference of a rolling bearing ring, which can be connected to the assembly to be rotated, such as the nacelle of a wind turbine or the slewing platform of a crane, and forms part of a rolling bearing with which the assembly is rotatably mounted.Such toothed rolling bearings often form large roller bearings with diameters of more than half a meter or even several meters in order to be able to support the high weight and the high bearing forces of the assembly to be rotated.

[0004] To prevent damage to the teeth on the gear ring or even the slewing bearing ring in overload situations, the drive and / or adjustment device often features overload protection, which prevents the transmission of excessive torque or forces to the component being rotated, and in particular to the gear ring on the rolling bearing ring. Such overload protection often provides a predetermined breaking point on a drive train component, which does not cause major damage and, above all, is easier to replace than, for example, the toothed bearing ring of a slewing bearing. The latter is almost impossible to replace, as this would require dismantling the often massive, heavy assembly, such as the slewing platform with the entire superstructure of a crane or the nacelle with the entire rotor of a wind turbine.

[0005] Such a predetermined breaking point can be provided, for example, in the output shaft which drives the pinion meshing with the gear ring, whereby the output shaft can be weakened in diameter at one point so that it can withstand the operating load but breaks statically at a predetermined overload.

[0006] Such overload protection in the form of a predetermined breaking point by weakening the output shaft of a slewing gear drive is shown, for example, in document US 2011 / 0027006 A.

[0007] To adjust the predetermined breaking load or the predetermined breaking torque, the diameter of the output shaft can essentially be changed, the size of the diameter reduction can be changed, or the material of the output shaft can be adapted accordingly. However, both of these can only be changed to a limited extent or even freely selected, as the available installation space is very limited depending on the application, and the output shaft and output shaft housing are often customer-specific components that are individually adapted to the respective application, meaning that a specific solution must be found for each application. In addition, overload protection is difficult to retrofit, as the installation environment is predetermined and thus the variation options for modifications to the output shaft are limited.

[0008] In addition, a predetermined breaking point in the output shaft of a rotary actuator requires modification of the output shaft and output shaft housing, as the reduction in diameter or the predetermined breaking point typically lengthens the gearbox. Furthermore, a spacer washer is usually required. Overall, the complexity of the parts to be modified is very significant, so the required modification of the raw parts and the associated costs are very high for a small series.

[0009] Another problem arises from the load case. Output shafts equipped with a predetermined breaking point in the form of a tapered section are generally suitable for use in a wide load range with regard to fatigue load and static load under pulsating loads. However, under fluctuating loads, the range is severely limited, as the predetermined breaking point becomes very thick at high fatigue loads. This means that the predetermined breaking point does not fail when the static load is low, as otherwise the fatigue cannot be tolerated.

[0010] Based on this, the present invention seeks to create an improved drive and / or actuating device of the aforementioned type that avoids the disadvantages of the prior art and advantageously develops them further. In particular, an improved overload protection system is to be created that reliably protects the assembly to be rotated or difficult-to-replace structural parts under both pulsating and fluctuating loads and is easily adaptable to various applications and load cases.

[0011] According to the invention, the stated object is achieved by a drive and / or actuating device according to claim 1. Preferred embodiments of the invention are the subject of the dependent claims.

[0012] It is therefore proposed to provide the overload protection on a gear of the transmission which is connected upstream of the output element of the drive train and which drives or adjusts the assembly to be rotated via said output element. The gear is designed such that in the event of an overload it interrupts the drive train and no longer transmits drive torque. According to the invention, the gear is split and has two parts which are connected to one another via spur gearing in a torque-transmitting manner and are held axially in spur gear engagement by an axial locking device which gives way between the gear parts when a predetermined axial load is applied. If the axial locking device gives way when an excessive axial load is applied, the gear parts can axially move away from one another, so that the spur gear engagement between the gear parts is released and the gear parts can be rotated relative to one another.Due to the oblique tooth flanks, the spur gearing between the gear parts generates axial forces that depend on the transmitted torque, so that an overload case is accompanied by an excessive axial force, which can then lead to the axial locking device being triggered.

[0013] By integrating the overload protection into a gear of the gearbox, it is sufficient to replace only one component of the drive train, and the overload protection can be easily retrofitted to existing rotary drives. Furthermore, the overload protection can be easily adapted to different applications and drive cases with regard to the triggering torque or triggering load. Above all, a defined triggering of the overload protection can be achieved for both pulsating and fluctuating loads, without major differences between the load cases, since the axial locking device is largely only subjected to pulsating tensile loads. The spur gear engagement between the two gear parts only generates pulsating tensile loads on the axial locking device, even with changing directions of rotation or changing loads, thus resulting in advantages compared to conventional predetermined breaking points in the output shaft, particularly in the case of fluctuating loads.

[0014] It is particularly advantageous if the overload protection is integrated into the sun gear of a planetary gear, via which the output element of the drive and / or adjustment device and thus the assembly to be rotated is driven or adjusted. In particular, the sun gear of the planetary gear can be split in the manner mentioned and have two sun gear parts that are connected via spur gearing to transmit torque and are held axially by the axial locking device in spur gearing engagement and thus rotationally fixed to one another until the axial locking device yields and the sun gear parts can axially deflect and disengage from the spur gearing.

[0015] The sun gear of an output stage can usually be the same for different rotary drives of the same size, so that two blanks per series size are sufficient. At the same time, compared to a conventional, undivided sun, the length of the sun gear can be maintained, thus avoiding further adjustments to the installation environment, such as redesigning the gearbox housing. Nevertheless, numerous adjustment or adaptation options exist to control the triggering of the overload protection, for example, by changing the gear geometry with regard to pressure angle and / or tooth length and / or tooth direction and / or number of teeth, or by designing the axial locking device.

[0016] The axial locking mechanism is designed to be simple and rigid, holding the two gear parts rigidly and immobilely together until triggered in the event of an overload. Since the torque is transmitted only via the spur gear engagement, the axial locking mechanism is subjected to only tensile stress, meaning it does not have to withstand any bending moments or allow any movement.

[0017] The axial locking mechanism forms a predetermined breaking point between the two gear parts. If the axial locking mechanism breaks under a predetermined overload, the two gear parts can move axially toward each other, i.e., along the gear's rotational axis, and can move away from each other to release the spur gear mesh. This then enables the gear parts to rotate relative to each other, interrupting the drive train.

[0018] In principle, it would be possible to design the axial locking mechanism to be elastic or resilient, so that when a predetermined axial load is reached between the gear parts, it yields, for example, by elongating to release the spur gear engagement and allow the gear parts to rotate relative to each other. However, this would result in slippage of the gear distribution, with the teeth chattering against each other, which would lead to corresponding damage to the spur gear teeth of the gear parts. Therefore, it may be more cost-effective to design the axial locking mechanism as a predetermined breaking point and replace it after it breaks, since the undamaged gear parts can then be reused.

[0019] In an advantageous development of the invention, the axial securing means may comprise one or more tension bolts, for example in the form of one or more screws, which hold the two gear parts together in spur gear engagement and serve as a predetermined breaking point if, in the event of an overload, the spur gearing causes an excessive axial load on the tension bolts or screws.

[0020] Advantageously, each of the two parts of the gear can have circumferential teeth, through which the gear parts are in rolling or meshing engagement with upstream and downstream gear elements of the drive train, transmitting torque. In this case, the gear parts have teeth on the one hand on the circumferential side and teeth on the other hand, via which the drive or adjusting torques or forces of the drive train are transmitted. If the aforementioned axial locking device is triggered and the spur gearing between the gear parts becomes disengaged, each gear part or each gear half can continue to mesh and remain integrated with the upstream or downstream gear element of the drive train via its circumferential teeth. Nevertheless, no drive or adjusting movement is transmitted.

[0021] To allow for axial deflection, at least one of the gear parts can be mounted for axial movement—if the axial locking device is ignored or the case is triggered. It may be sufficient if the bearing of at least one gear part has sufficient axial play to disengage the spur gear teeth. The gear parts are held together axially only by the axial locking device, and the bearing of the gear parts is designed in such a way that if the axial locking device breaks or is triggered, the gear parts can move axially apart to such an extent that the spur gear teeth disengage.

[0022] The said spur gearing can fundamentally be designed in different ways. In an advantageous development of the invention, a Hirth gearing can be provided on the gear halves or parts. However, other spur gearing types can also be provided, wherein the spur gearing of the gear parts preferably does not have any axial locking that would hold the gear parts together if the axial lock breaks. In particular, the teeth of the spur gearing can be configured with regard to pressure angle and / or tooth length and / or tooth direction and / or tooth flank contour and / or number of teeth such that, at a predetermined torque between the gear parts, a sufficiently large axial force is generated between the gear parts. This force drives the gear parts apart and can thus release the spur gear engagement if the axial lock is broken or has triggered.

[0023] In order to prevent damage to the gear parts or other gear elements from fragments of the axial locking device, an advantageous development of the invention can provide a catch for broken axial locking pieces. In particular, such a catch can hold or catch broken pieces of the tension bolts or screws in or on the gear part to which the bolt or screw piece was mounted in an unbroken state. For example, the bolts or screws can be secured to both gear parts so that even in a broken state, the bolt pieces or screw pieces remain in their intended assembly position. For example, the bolts or screws can be countersunk or at least flush-mounted with their heads or nuts and secured to the gear part by a cover, a retaining clip or the like in the event of breakage.

[0024] If the overload protection device is triggered due to the breakage of the axial locking device or at least one tension and / or screw bolt, the broken axial locking device can be removed and replaced with a new, undamaged axial locking device, allowing the split gears to be reused. All that's required is to re-engage the two gear parts with their spur gears and, depending on the design of the axial locking device, insert one or more new screw bolts and / or tension bolts to hold the two gear parts together.

[0025] If the overload protection is integrated into the sun gear of a planetary gear stage as described above, one part of the sun gear can be connected to the planet carrier of the upstream or downstream gear stage via a running gear. Alternatively or additionally, the other half of the sun gear can form the actual sun gear or have a running gear with which the aforementioned half of the sun gear meshes with the planets of the planetary stage.

[0026] The invention is explained in more detail below using a preferred embodiment and the accompanying drawings. In the drawings: Fig. 1: a perspective view of a wind turbine, the nacelle of which is mounted in a rotationally driven manner via a large roller bearing with a gear ring, Fig. 2: a perspective view of the drive and / or adjustment device for rotationally driving or adjusting the large roller bearing having the gear ring, with which the nacelle of the wind turbine is made of Fig. 1 can be supported, Fig. 3: a sectional view of the sun gear of a planetary gear stage of the drive and / or adjusting device from the previous figures, showing the split design of the sun gear as overload protection, and Fig. 4: a sectional view of a sun gear similar Fig. 3 , whereby the two parts of the sun gear are not held in spur gear engagement with several screw and / or tension bolts, but with a central screw bolt.

[0027] How Figure 1As shown, the drive and / or adjustment device can be used in a wind turbine 1 to rotate its nacelle 24 about an upright axis or to adjust its azimuth angle. The rotor 3 can be mounted on the nacelle 24 or a nacelle for rotation about a horizontal rotor axis, wherein the nacelle 24 itself can be mounted on a tower 2 for rotation about an upright axis by means of a large-diameter rolling bearing.

[0028] Rotor blades 5 can be mounted on the rotor hub 4 for rotation about longitudinal rotor blade axes, the pitch angle of which can be adjusted by means of a drive and / or adjustment device. Similarly, the nacelle 24 can be rotated by a drive and / or adjustment device.

[0029] How Figure 2shows, the aforementioned azimuth bearing 7 - and similarly also the pitch bearing 6 - can be designed in the form of a large roller bearing having two mutually rotatable bearing rings, one of which can be provided on the inner circumference or outer circumference with a toothing in the form of a gear ring 8. In order to be able to rotationally adjust the component to be rotated in the form of the gear ring 8 or the bearing ring connected thereto, a drive and / or adjustment device 11 is provided, which can comprise a pinion as an output element 25, which meshes with the gear ring 8 in order to drive the latter rotationally.

[0030] How Figure 2 shows, several drive and / or adjustment devices 11 can also be provided in order to jointly drive or adjust the component to be rotated.

[0031] The said drive and / or adjustment device 11 can have a drive motor 9, for example in the form of an electric motor or a hydraulic motor, whose rotary drive movement drives an output shaft 12 via a gear 10, on which the output element 25 in the form of the pinion is seated.

[0032] Said transmission 10 can be designed, in particular, as a single-stage or multi-stage planetary transmission, in which a sun gear 13 meshes with planetary gears that are rotatably arranged on a planetary carrier around the sun gear 13. Depending on the design of the planetary transmission, the planetary carrier can be fixed or rotatably mounted.

[0033] In a manner known per se, the planetary gears mentioned can mesh with a ring gear which is arranged around the planets and which can be fixedly arranged on the gear housing 14 or, depending on the design of the planetary gear, can also be rotatably mounted.

[0034] How Figure 3shows, an overload protection device 20 is provided on the sun gear 13 in order to prevent damage to the gear ring 8 of the component to be rotated or even damage to the component to be rotated itself, for example to the bearing ring of the azimuth bearing 7, in the event of an overload. The aforementioned overload protection device 20 interrupts the flow of force or torque at the sun gear 13 and disconnects the drive train, so that no torque and no drive movement are transmitted from the drive motor 9 to the output element 25 at the sun gear 13 and, conversely, no reaction forces or torques are transmitted from the output element 25 to the drive motor 9.

[0035] How Figure 3shows, the sun gear 13 is split and comprises two gear parts or halves 13a and 13b, which are connected to one another in a rotationally fixed manner by the overload protection device 20 during normal operation. The two gear parts 13a and 13b can be separated from one another by a parting plane perpendicular to the axis of rotation 14 of the sun gear 13 or can be in contact with one another and connected. In particular, the two gear parts 13a and 13b can touch one another and be connected to one another at opposite end faces. In order to be able to transmit torque during normal operation, the two gear parts 13a and 13b are engaged and rotationally fixedly connected to one another by means of a spur gearing 15. The spur gearing 15 can have gear rings or segments or rows that can be brought into engagement with one another and are provided on the end faces of the sun gear parts 13a and 13b.

[0036] The said spur gearing 15 is advantageously not self-locking or configured in such a way that no axial locking occurs in order to be able to separate the gear parts 13a and 13b from one another in the axial direction and to be able to release the spur gear engagement when the overload protection device 20 is triggered and the two gear parts 13a and 13b are released axially from one another.

[0037] To avoid such axial locking, the angles of the tooth surfaces of the spur gearing 15 can, for example, be selected to be sufficiently large. Alternatively or additionally, axial locking can also be avoided by other gearing parameters, such as the pressure angle, the tooth length, the tooth direction, or the number of teeth of the spur gearing segments.

[0038] For example, the said spur gearing 15 can be designed as a so-called Hirt spur gearing.

[0039] In order to keep the spur gearing 15 engaged during normal operation and to connect the gear parts 13a and 13b to one another in a rotationally fixed manner, the overload protection device 20 comprises an axial safety device 16 which holds the two gear parts 13a and 13b axially in spur gear engagement with one another and can be designed as a predetermined breaking point in order to trigger when a predetermined torque between the two gear parts 13a and 13b is exceeded and thus a predetermined axial force generated via the tooth geometry is exceeded.

[0040] Advantageously, the said axial securing means 16 can comprise one or more tension bolts 17, for example in the form of screw bolts, which can be arranged distributed around the rotational axis 14, for example, and hold the two gear parts 13a and 13b axially against one another, cf. Figure 3 .

[0041] How Figure 4shows, the two gear parts 13a and 13b can also be held axially against one another by only one tension bolt 17, for example in the form of a screw bolt, whereby when only one tension bolt 17 is used, the latter can advantageously be arranged centrally or coaxially to the axis of rotation, cf. Figure 4 . Such a central tension bolt 17 advantageously does not pass through the spur gearing 15, but is surrounded by the said spur gearing 15, which can be radially spaced from the tension bolt 17, cf. Figure 4 .

[0042] The torque between the gear parts 13a and 13b is advantageously transmitted solely by the spur gearing 15, while the axial locking device 16, in particular its tension or screw bolts 17, are subjected solely or at least primarily to axial tension parallel to the rotational axis 14. The aforementioned axial forces on the tension or screw bolts 17 arise from the inclined tooth flanks, which attempt to drive the gear parts 13a and 13b apart with a wedge effect.

[0043] The aforementioned tension or screw bolts 17 are advantageously matched to the spur gearing 15 in such a way that a predetermined breaking point, and thus a triggering of the overload protection device 20, occurs at a predetermined torque on the gear parts 13a and 13b. More precisely, the screw or tension bolts 17 are configured such that they break at a predetermined axial load. In conjunction with the design of the spur gearing geometry, this can achieve a triggering of the overload protection device 20 at a predetermined torque.

[0044] Due to the breakage of the tension or screw bolts 17, the axial load emanating from the spur gearing 15 can no longer be transmitted, and the spur gearing 15 or the gear parts 13a and 13b are driven axially apart, thereby interrupting the drive train in the transmission 10 at the sun gear 13. This causes the output stage or the drive and / or adjustment device to be switched load-free.

[0045] As a result, the gear 10, or more precisely the sun gear 13, fails under overload before, for example, the gear ring 8 on the large roller bearing breaks.

[0046] To prevent further damage to other transmission elements caused by fragments of the tension or screw bolts 17, the aforementioned tension or screw bolts 17 can advantageously be mounted in such a way that they remain attached to the gear parts 13a and 13b even after breaking. A safety catch 18 can hold the broken axial securing parts to the gear parts 13a and 13b, particularly in their intended assembly position, which is also assumed in the unbroken state.

[0047] How Figure 3shows, the screw bolts 17 can, for example, extend through one of the gear parts 13a or through through recesses formed therein and be screwed into screw threads provided in the other gear part 13b, for example in the form of a blind hole thread. The bolt part screwed into the blind hole thread, possibly broken off, remains in the gear part 13b as a result of the screwing. In order to also hold the other broken off bolt part in the gear part 13a, the safety catch 18 can hold the bolt head on the end face of the gear part 13a. For example, a lid or cover can be placed over the bolts 17 or their heads, which are located on the end face of the gear part 13a.

[0048] How Figure 4shows, the axial securing means 16, regardless of whether only one or several tension bolts 17 are provided, can also extend through a through-hole passing through both gear parts 13a, 13b and be secured by means of a nut 17m, which can be axially supported on one of the gear parts 13b. The said nut 17m can be mounted in an axially protruding manner, as shown in Figure 4 shows, but may also be mounted countersunk in the respective gear part 13b, similar to how it is shown in Figure 4 for the head of the tension bolt 17. The aforementioned safety catch 18 can also be provided when using a screwed-on nut 17m, in which case the safety catch 18 can comprise two safety catch parts, one of which is assigned to the tension bolt head and another to the aforementioned nut, in order to hold the latter firmly to the respective gear part 13a or 13b in the event of breakage.

[0049] For example, an expansion screw or a carbon rod can be used as the tension bolt 17.

[0050] By providing the overload protection 20 on the sun gear 13, the following advantages in particular can be achieved: The length of the sun gear 13 or its axial extension in the direction of the rotational axis 14 can be retained. To retrofit the overload protection device 20, only one part needs to be replaced, so that existing rotary drives can be easily retrofitted. In addition, the sun gear 13 of the output stage is the same for different rotary drives of a series size, meaning that only two new blanks need to be created per series size. The overload protection device 20, in the form of the predetermined breaking point of the axial lock 16 or the draw bolt 17, is largely subjected to a pulsating tensile load even with changing directions of rotation, so that differences in function between pulsating and alternating loads are reduced and the overload protection device 20 reliably triggers equally under pulsating loads and alternating loads.In comparison to previous predetermined breaking points on the output shaft, this offers particular advantages with regard to loads in varying ranges. There are numerous setting and adjustment options to adapt the triggering of the overload protection device to the respective application or load case. For example, in the area of ​​the spur gearing 15, the tooth shape can be varied, in particular the pressure angle, the tooth length, the tooth direction, and the number of teeth. On the axial locking device 16 side, the screw or bolt shape, the number of tension or screw bolts 17, their material, and cross-sectional dimensions can also be changed in order to adjust the triggering of the overload protection device 20. An existing drive and / or adjustment device can be easily retrofitted with an overload protection device 20, whereby the gear 10 can be converted simply by replacing the gear or the sun gear 13 without further modifications to the installation environment.

[0051] How Figure 3As shown, the two gear parts 13a and 13b can each be provided with a running toothing 19 on their circumference in order to be in meshing or rolling engagement with an upstream or downstream gear element and to be able to transmit a corresponding drive movement. Depending on the design of the gear 10, these can be different gear elements. For example, the gear part 13a with its running toothing 19 can be connected to a planet carrier of a previous planetary gear stage or can be in meshing engagement. The other gear half 13b can mesh with the planets of the planetary gear stage with its running toothing 19 and thus form the actual sun of the planetary gear or planetary stage.

[0052] In order to separate or interrupt the flow of force or torque after the axial securing device 16 has broken, at least one of the gear parts 13a and 13b can be mounted so as to be movable axially in the direction of the rotational axis 14, for example by means of sufficient bearing play or a sufficiently dimensioned clearance in the axial direction.

[0053] Advantageously, the transmission, in particular the bearing of the gear 13, can be designed such that the two-part gear 13 with the overload protection 20 can be replaced by a one-piece gear of the same or similar dimensions without an overload protection, so that the transmission can be operated or put into operation either with the two-part gear 13 with an overload protection or with a conventional gear without an overload protection. In particular, this also makes it easy to retrofit a conventional transmission without an overload protection with an overload protection by replacing a previously one-piece sun gear with a two-piece sun gear, which, in the manner described, comprises two gear parts 13a, 13b, which are brought into spur gear engagement and can be held in said spur gear engagement by an axial lock.Depending on the design of the conventional, one-piece gear, it may be advantageous to use several off-center locking bolts, as shown in . Figure 3 shown, or to use the version with a central locking bolt, as shown Figure 4 In particular, the gear 13 can be mounted detachably and replaceably, so that one or the other variant can be used optionally.

Claims

1. Drive and / or adjustment device (11) for driving and / or adjusting a rotatable assembly, for example a large rolling bearing ring of a wind turbine or a slewing gear of a construction machine or of a hoist, comprising an output element (25) for rotationally driving and / or adjusting the rotatable assembly, a transmission (10) which is connected upstream of the output element (25) and comprises at least one torque-transmitting gear (13), and an overload safety mechanism (20) for the rotatable assembly, wherein the overload safety mechanism (20) is provided on the gear (13), which is divided and comprises two gear parts (13a, 13b) that are torque-transmittingly interconnected via a spur toothing (15) and are held axially in spur toothing engagement by an axial securing means (16) which yields at a predetermined axial load between the gear parts (13a, 13b), characterized in that the axial securing means (16) is rigidly configured and forms a predetermined breaking point.

2. Drive and / or adjustment device according to the preceding claim, wherein the transmission (10) is a planetary gear with a divided sun gear (13) forming the overload safety mechanism (20).

3. Drive and / or adjustment device according to the preceding claim, wherein the sun gear (13) on the sun gear parts (13a, 13b) meshes on the one hand with planet gears of a first planetary gear stage and, on the other hand, with the planet carrier of a second, upstream or downstream planetary stage.

4. Drive and / or adjustment device according to any one of the preceding claims, wherein the split gear wheel on the gear parts (13a, 13b) each comprises a meshing toothing (19) on the peripheral side, via which the gear parts (13a, 13b) are in a rolling engagement on the one hand with a downstream gear element and on the other hand with an upstream gear element, wherein said meshing toothing (19) is preferably configured such that the gear parts (13a, 13b) are axially displaceable in the direction of the axis of rotation (14) relative to the upstream and downstream gear elements and / or the gear parts (13a, 13b) are not subject to axial forces from the upstream and downstream gear elements.

5. Drive and / or adjustment device according to any one of the preceding claims, wherein the spur toothing (15) between the gear parts (13a, 13b) is configured to be axially impediment-free, in the engaged position, even during torque transmission, in particular as a Hirth joint.

6. Drive and / or adjustment device according to any one of the preceding claims, wherein the axial securing means (16) comprises one or more tension and / or screw bolts (17) which is / are seated in axial recesses in both gear parts (13a, 13b) and holds / hold the gear parts (13a) against one another on the end face, in particular clamps / clamp one against the other.

7. Drive and / or adjustment device according to the preceding claim, wherein the tension and / or screw bolts (17) extend through the spur toothing (15) and / or are arranged parallel to the axis of rotation (14) of the gear (13) and spaced from said axis of rotation (14).

8. Drive and / or adjustment device of claim 8, wherein the axial securing means (16) comprises a central tension and / or screw bolts (17) extending coaxially with the axis of rotation (14) of the gear (13) and surrounded by the spur toothing (15) and the axial securing means (16) extends completely through one of the gear parts (13a) in the axial direction and is screwed into a blind hole in the other gear part (13b).

9. Drive and / or adjustment device according to any one of claims 8 to 11, wherein the axial securing means (16) extends axially through a through bore passing through both gear parts (13a, 13b) and is screwed to a nut (17m) which is axially supported on one of the gear parts (13b).

10. Drive and / or adjustment device according to any one of the preceding claims, wherein a catching means is provided for retaining the axial securing means (16) even in the broken state on the gear parts (13a, 13b) in the intended assembly position.

11. Drive and / or adjustment device according to any one of the preceding claims, wherein the axial securing means (16) is configured to be detachable from the gear parts (13a, 13b) even in the broken state, and is replaceable by a new unbroken axial securing means (16), by means of which the gear parts (13a, 13b) can again be brought into their intended spur toothing engagement.

12. Drive and / or adjustment device according to any one of the preceding claims, wherein the axial securing means (16) and the gear parts (13a, 13b) are configured in such a way that the gear parts (13a, 13b) exert axial forces on the axial securing means (16) for the most part, in particular exclusively, while torques between the gear parts (13a, 13b) are transmitted essentially, preferably exclusively, by the spur toothing (15).

13. Drive and / or adjustment device according to any one of the preceding claims, wherein the output element (25) is configured as a pinion which is seated in a rotationally fixed manner on an output shaft of the transmission (10) and meshes with a gear rim attached to the assembly to be rotated, wherein the output shaft is configured to be free of rated breaking points and notches.

14. Drive and / or adjustment device according to any one of the preceding claims, wherein the transmission (10) is connected on the input side to a drive motor in the form of an electric motor or hydraulic motor, the rotational drive movement of which is transmitted via the transmission (10) to the output element (25), which is preferably arranged coaxially with the motor shaft of the drive motor (9).

15. Drive and / or adjustment device according to any one of the preceding claims, wherein the gear (13) having the overload safety mechanism (20) is replaceably mounted in the transmission (10) and can be replaced by a dimensionally identical or matching gear (13) without overload safety mechanism, so that the transmission (10) can be put into operation selectively with the overload-protected gear (13) or the gear (13) without overload safety mechanism.