CN109790908B

CN109790908B - Overload protection device

Info

Publication number: CN109790908B
Application number: CN201780046467.1A
Authority: CN
Inventors: 马库斯·比尔德施泰因
Original assignee: Liebherr Aerospace Lindenberg GmbH
Current assignee: Liebherr Aerospace Lindenberg GmbH
Priority date: 2016-07-25
Filing date: 2017-07-25
Publication date: 2022-04-29
Anticipated expiration: 2037-07-25
Also published as: DE102016009037A1; WO2018019417A1; FR3054278B1; FR3054278A1; CN109790908A

Abstract

The invention relates to an overload protection device, comprising: a driver for generating a rotational movement; a conversion device for converting a rotational movement into a linear movement of the adjusting element; and a housing for supporting the switching device, wherein the switching device is movably supported in the housing along the linear movement of the adjusting element.

Description

Overload protection device

Technical Field

The invention relates to an overload protection device for a linear-action mechanical actuating device.

Background

The adjusting devices in aircraft require overload protection devices which limit the adjusting force in order to prevent overloading of the aircraft structure. It is important here that the divergence of the force limitation is as small as possible, since the aircraft structure must be dimensioned for the largest possible force, and a small divergence represents a small structural weight.

In general, a linear-acting mechanical actuating device is formed by a rotary motor (e.g., an electric motor) and a transmission, which converts a rotary motion into a linear motion (e.g., a spindle). The transmission is typically extended in steps to increase the rotational speed, in order to be able to reduce the weight of the rotary motor. It is known from EP 1878658 a2 to provide a clutch for limiting overload in such a control device in the load path of the rotary system. Such an overload clutch is preferably used in a range of high rotational speeds in order to keep the overall dimensions small.

A disadvantage of this device is that the magnitude of the force acting on the overload function is subject to large divergence. The reason for this is that not only the transmission but also the clutch are frictional.

FIG. 1 depicts and quantifies associations. Fig. 1 shows the behavior of the torque at the clutch when the linear force of the actuating device changes. Axis 10 shows linear force in the direction of pressure and axis 20 shows linear force in the direction of tension. Axes 30 and 40 show the positive and negative torque on the clutch corresponding to the force direction. Only the representation in the upper right quadrant of the icon is considered below. Meaningfully, the same behavior exists in the lower left quadrant. Two types of operation are shown. Line 50 shows the torque development at the force increase for the following cases: the regulating device drives the control surface ("driving case") and the line 60 shows the same association for the following cases: the regulating device is driven by the control plane ("run-back situation"). Additionally, a dashed line 70 is drawn, which shows the same relationship in the theoretical case, i.e. the process proceeds without friction. The line 70 is effective for driving and run-back conditions. Line 50 (the driving condition) is steeper than dashed line 70 because more torque is required to overcome friction to produce the same force. The illustrated change in slope 80 corresponds to an efficiency of the transmission of approximately 69%. The efficiency is achievable for a control device at low temperatures, which is formed by a ball screw with a roller thrust bearing and a roller-mounted spur gear. Line 50 rises until it intersects line 90. Line 90 corresponds to the lowest torque at which the clutch is activated. Similarly, line 100 shows the highest torque at which the clutch is activated. This results in a divergence of the clutch torque 110 that is caused by friction and production tolerances.

This is assumed in fig. 1 at 15% to be of the order of magnitude achievable up to optimism for a rotating overload clutch. Now determined is the intersection of

lines

50 and 90, indicated at 120. The intersection point defines a minimum adjustment force 130 that the adjustment device is capable of generating. The adjusting device is designed such that the minimum adjusting force 130 also corresponds to the adjusting force which the aircraft must provide at any time during the flight at the control surface. The force is expressed in 100% as a benchmark for force overshoot, which is now observed below.

In addition to the drive situation observed hitherto, the return operation situation is also observed. The return travel means that the air load acts on a control surface which attempts to return the control device. The backward travel must be excluded up to the load 130, since it is aerodynamically necessary to maintain the load up to said value. However, if the load is exceeded in exceptional cases, usually temporarily, the regulating device must withdraw the load as early as possible in order to prevent damage to the aircraft structure. The height of the "retraction load" is readable in fig. 1 when line 60 is viewed. The slope of line 60 compared to line 50 is now less than the slope of dashed line 70, which dashed line 70 shows frictionless operation. The reason is that as the force rises, less torque reaches the clutch due to friction. The illustrated change 140 in slope again corresponds to an already mentioned efficiency of the transmission of approximately 69%. Line 60 rises until it intersects line 100. As already described, line 100 corresponds to the maximum torque at which the clutch is activated. Now determined here is the intersection of

lines

60 and 100, indicated at 150. The intersection point defines a maximum adjustment force 160 that can hold the adjustment device in reverse. In the friction relationship assumed here in the regulating device, a maximum load of 219% is thus obtained, which means that the aircraft structure is designed 2.19 times more strongly than is required aerodynamically. It can be seen that the large divergence of the forces for triggering the overload function represents a significant disadvantage with respect to the weight and cost of the aircraft structure.

Disclosure of Invention

The object of the present invention is to overcome the disadvantages mentioned above and to provide an overload protection device for a linear-action, mechanical actuating device, which has a low divergence of the forces for triggering an overload function. This furthermore leads to a reduction in the maximum loads acting on the aircraft structure, so that a weight reduction in the regulating device and in the aircraft structure is achieved.

The overload protection device according to the invention comprises a drive for generating a rotational movement, a conversion device for converting the rotational movement into a linear movement of the adjusting element, and a housing for supporting the conversion device. The overload protection device is further characterized in that the switching device is mounted in the housing so as to be displaceable along the linear movement of the actuating element.

Since the conversion device is mounted in the housing so as to be movable along the linear movement of the actuating element, the conversion device, i.e. the group of components which converts a rotary movement into a linear movement, can be moved along the linear movement of the actuating element in the event of an overload acting on the actuating element. This is done, for example, in the following cases: excessive tensile or compressive forces act on the adjustment element. Through the displaceable mounting of the shifting device, it is then possible to transfer the clutch, which transmits the force line between the drives to the shifting device, into the disengaged state. This is then simply done by an axial displacement of the switching device in the direction of the linear movement of the actuating element.

Since the divergence of the triggering force of the overload protection device is determined solely by the friction in the linear movement, the divergence is independent of the friction relationships in the ball screw, the transmission and the rotary clutch and thus also of the type of operation "driving situation" and "back running situation", as already described in connection with fig. 1. The divergence of the triggering force of the overload protection device is therefore significantly smaller than in the case of the overload protection device according to the prior art.

According to an alternative embodiment of the invention, the overload protection device further comprises a coupling device for decoupling the force line between the drive and the switching device, wherein the coupling device is designed to be triggered when a force acting on the switching device and oriented in the direction of the linear movement of the actuating element is exceeded, i.e. to enter a state in which the force line from the drive to the switching device is interrupted. Preferably, the clutching device is disconnected under both tension and compression.

For this purpose, the switching device is arranged in the housing of the overload protection device in such a way that it is movable under the tension of the actuating element and under the pressure of the actuating element. If the tension or compression force exceeds a predetermined level, this causes: the switching device is moved within the housing in a direction parallel to the linear movement of the actuating element and in this case the clutch is transferred into the decoupled state.

According to a further development of the invention, the switching device is a ball screw, preferably an inverse ball screw, which comprises a screw nut, balls and a screw as the adjusting element. The inverse ball screw is characterized in that it has a substantially cylindrical spindle nut, on the inner side of which a helically running groove is provided, which groove is suitable for receiving balls. The balls provided therein can co-act with corresponding grooves in the outer circumference of the screw such that, when the screw nut is rotated and when the screw is inhibited from rotating, the rotational movement of the screw nut is converted into a linear movement of the screw.

It can furthermore be provided that the coupling device has an output gear, a torque transmission sleeve and a torque introduction sleeve, which are each arranged such that their rotational axes are oriented parallel to the linear movement of the actuating element. Typically, the drive gear circumferentially surrounds the screw nut. The drive gear furthermore has a spur toothing which extends in the direction of the linear movement of the adjusting element. The gear wheel therefore has a first toothing running in the radial direction and a second toothing running perpendicular to the radial direction, namely a spur toothing. The spur toothing of the torque transmission sleeve can be engaged with said spur toothing. The spur toothing likewise surrounds the spindle nut in the circumferential direction and is arranged slidably in the circumferential direction of the spindle nut. I.e. the screw nut can rotate independently of the movement of the torque transmission sleeve. The output gear, which rotates about the axis of rotation of the screw nut, is thus able to transmit the rotation to the torque transfer sleeve. Furthermore, a torque introduction sleeve is provided, which is connected to the spindle nut in a rotationally fixed manner. The torque introduction sleeve can surround the spindle nut in the circumferential direction, wherein the output gear likewise surrounds the torque introduction sleeve in the circumferential direction. The torque introduction sleeve furthermore likewise has a toothing oriented in the direction of the linear movement of the adjusting element in order to engage with the spur toothing of the torque transmission sleeve.

When the output gear and the torque introduction sleeve are engaged with the toothing of the torque transmission sleeve by means of their respective positive toothing, this only causes a rotation of the spindle nut if the output gear rotates about its axis of rotation.

According to an alternative development of the invention, the output gear has a toothing which is directed radially outward in order to mesh with the drive gear via an intermediate gear. In a further embodiment, which is not shown, the connection between the drive gear and the output gear can also take place directly via a bevel gear mechanism of structural form. The axis of the rotary motor can, for example, be at right angles to the direction of the linear movement, which can eliminate the necessity of an intermediate gear. Furthermore, it has a spur toothing in order to be able to engage with the spur toothing of the torque transmission sleeve. Furthermore, the torque introduction sleeve can have a toothing which is oriented inward in the axial direction in order to engage with a conversion device, in particular a spindle nut. The torque introduction sleeve also has a spur toothing in order to be able to engage with the spur toothing of the torque transmission sleeve.

Preferably, the drive gear is arranged rigidly on the housing with respect to the direction of the linear movement of the adjusting element and the torque transmission sleeve is arranged rigidly on the conversion device with respect to the direction of the linear movement of the adjusting element. When the switching device or the spindle nut of the switching device is moved in the direction of the linear movement of the spindle, the output gear is correspondingly also moved toward the torque introduction sleeve. It is thereby possible to disconnect the lines of force closed via the torque transmission sleeve. This can be done by releasing the engagement between the torque transmission sleeve and the torque introduction sleeve or between the output gear and the torque transmission sleeve. For example, it is conceivable for the torque introduction sleeve to be used for pushing out the torque transmission sleeve from the meshing engagement with the output gear. Alternatively, the torque introduction sleeve can also be simply pulled out of engagement with the torque transmission sleeve due to the movability of the conversion means in the direction of the linear movement of the adjustment unit.

In order to perform the breaking of the force line only at a predetermined level, there are fixing devices which hold the switching device in a predetermined position with a certain force. According to a preferred embodiment of the invention, the torque introduction sleeve is mounted on the switching device, in particular on a spindle nut of the switching device, so as to be immovable in the direction of the linear movement of the adjusting element.

Preferably, the torque introduction sleeve surrounds the switching device, in particular the spindle nut of the switching device, in the circumferential direction thereof and is arranged fixedly thereon. The output gear in this case surrounds the torque introduction sleeve in its circumferential direction, so that at the same time a spur toothing of the output gear and a spur toothing of the torque introduction sleeve can be brought into engagement with a toothing of the torque transmission sleeve.

If the spur toothing of the torque transmission sleeve engages with the spur toothing of the torque introduction sleeve and with the spur toothing of the output gear, the force line between the output gear and the torque introduction sleeve or the shifting device is closed. Rotation of the output gear about its axis of rotation then causes rotation of the conversion device, which rotation thereby causes linear motion.

According to a further development of the invention, the overload protection device also has a fastening device for elastically fastening the switching device to the housing in a direction parallel to the linear movement of the actuating element.

In this case, it can be provided that the fastening device has a spring element in which, in a state of low stress, the output gear is in engagement with the toothing of the torque transmission sleeve and the torque transmission sleeve is in engagement with the toothing of the torque introduction sleeve.

Preferably, when the switching device is moved relative to the housing in the direction of the linear movement of the actuating element, the clutch device is transferred into its open state, and the compressed or reduced compression of the spring element exerts a restoring force on the switching device in order to bring the clutch device back into its closed state.

Preferably, a movement of the shifting device in a direction parallel to the linear movement of the adjusting element suppresses a less stressed state of the spring element and causes the spur toothing of the output gear or of the torque introduction sleeve to disengage from the torque transmission sleeve.

It can furthermore be provided that the spring element is designed to exert a force on the conversion means in order to move the conversion means such that the clutch device is again transferred into its force-fit state.

According to an alternative development of the invention, the spring element is arranged between the torque transmission sleeve and a disk surrounding the spindle nut of the switching device, said disk being movable in the longitudinal direction of the spindle nut.

Preferably, the torque introduction sleeve is formed integrally with the conversion device, in particular with a spindle nut of the conversion device.

The invention further relates to an actuator comprising an overload protection device according to one of the variants described in detail above.

Also encompassed by the invention is an aircraft having an adjustment drive as defined above.

Drawings

Other features, details and advantages will be apparent from the following description of the drawings. Shown here are:

figure 1 shows a diagram for illustrating the disadvantages of the overload protection arrangement of the prior art,

figure 2 shows a schematic cross-sectional view of an overload protection apparatus according to the invention,

figure 3 shows a perspective cross-sectional view of a clutching device,

fig. 4 shows a perspective cross-sectional view of a clutch device, in which the torque-transmitting sleeves are spaced apart,

fig. 5 shows a schematic cross-sectional view of an overload protection device when a pressure acts on the adjusting element, which pressure causes the clutch device to open,

figure 6 shows a schematic cross-sectional view of an overload protection device with a drawn force line in the case of a pressure acting on the adjusting element,

figure 7 shows a perspective view of the clutch device in a pressure-decoupled state of the clutch device,

fig. 8 shows a schematic cross-sectional view of an overload protection device in the case of a tensile force acting on the adjusting element, which tensile force causes the disconnection of the clutch device,

figure 9 shows a schematic cross-sectional view of an overload protection device with a drawn force line in the case of a pressure acting on the adjusting element,

figure 10 shows a perspective partial section view of the clutch device in the decoupled state due to the tensile force,

fig. 11 shows a schematic cross-sectional view of an overload protection device with the adjusting element stopping at an end stop which causes the clutch device to open, an

Fig. 12 shows a schematic cross-sectional view of the overload protection device when it is in abutment against a further end stop which causes the clutch device to open.

Detailed Description

The basic idea of the invention is that the overload protection device is arranged as far as possible in the direction of the output of the adjusting device in order to minimize the influence of friction and thus the divergence of the triggering forces. For this purpose, the overload protection is arranged in the region of the linear action of the actuating device. Fig. 2 to 7 show exemplary embodiments of the present invention. The exemplary adjustment device consists of an electric motor 160, which drives an inverse ball screw 180 via a spur gear arrangement 170. The transmission is composed of a drive gear 190, an intermediate gear 200, and an output gear 210.

The intermediate gear 200 is required in order to establish a sufficiently large shaft offset with respect to the space requirement of the ball screw 180 for the electric motor. The reverse ball screw 180 is composed of a screw 220, a screw nut 230, and balls 240. The functional cooperation of the screw 220, the screw nut 230 and the balls 240 is the same as in a known ball screw transmission. The screw 220 is prevented from rotating by means not shown. The spindle nut 230 is prevented from moving axially in nominal operation by means described below. Nominal operation in this context means any operation outside the overload protection is effective. With this limitation in degrees of freedom, the screw 220 experiences the desired linear motion caused by the rotation of the screw nut 230.

According to the invention, overload protection is now achieved by: when the limit value of the axial force at the spindle 220 is exceeded, the torque-transmitting connection between the spindle nut 230 and the output gear 210 is broken. Thereby, the screw nut 230 can be rotated independently of the motor, and the screw 220 can be retracted by an external force. The releasable torque-transmitting connection is formed by the components output gear 210, torque transmission sleeve 250 and torque introduction sleeve 260. These three parts have positive teeth as shown in fig. 4.

Fig. 3 is a spatial sectional view of the three components in the state as shown in fig. 2.

Fig. 4 shows the same arrangement as in fig. 3, but axially separated from one another, so that the spur toothing is better visible. The torque line from the motor to the transmission 170 runs from there to the output gear 210, via the spur toothing of the output gear 210 to the torque transmission sleeve 250, from there to the torque introduction sleeve 260, which then introduces it via the radial claws 270 into the spindle nut 230. In order to ensure torque transmission in rated operation, the teeth must engage one another. The engagement of the spur toothing between the torque transmission sleeve 250 and the torque introduction sleeve 260 with one another is ensured by a disk spring pack 280, which is prestressed by means of the triggering force of the overload protection. The force line of the pretightening force is as follows: from the right end of the disk spring stack 280, the pretensioning force reaches the torque transmission sleeve 250, which is axially supported on the torque introduction sleeve 260. From there, the pretension is transmitted into the inner ring of the radial bearing 290, in order from there to return to the disk spring set 280 via the support ring 300, the spindle nut 230, the axial bearing 310 and the disk 320. The mutual engagement of the spur toothing between the output toothing 210 and the torque transmission sleeve 250 is ensured by: the device is only between the stationary

axial bearings

320 and 330 with minimal axial play and this prevents opening of the spur toothing.

Fig. 5 now shows a situation in which the pressure 340 acting on the adjusting device exceeds the trigger force of the overload means. Pressure 340 exceeds the preload of belleville spring stack 280, which results in: the spur gear portions of the output gear 210 and the torque transmission sleeve 250 are separated from each other.

Fig. 6 shows the force lines through the adjusting device. The screw nut no longer has a torque-transmitting connection with the motor 160, begins to rotate under the pressure load 340, and the screw 220 retracts. The mutual positions of the spur toothing in this state are also shown in fig. 7. The device 350 axially fixes the output gear 210 and prevents, due to the axial movement for compressing the set of belleville springs 280, the output gear 210 from moving axially to the left so that the spur teeth of the output gear 210 and of the torque transmission sleeve 250 no longer separate from one another.

Fig. 8 shows the situation in which the pulling force 360 acting on the adjusting device exceeds the triggering force of the overload means. The pulling force 360 exceeds the pre-tension of the disk spring stack 280, which results in: the spur teeth of the torque transmission sleeve 250 and the torque introduction sleeve 260 are separated from each other.

Fig. 9 shows the force lines through the adjusting device. The spindle nut no longer has a torque-transmitting connection to the motor 160, begins to rotate under the tension load 360, and the spindle 220 moves in the direction of the tension. The mutual positions of the spur toothing in this state are also shown in fig. 10. The device 370 fixes the torque introduction sleeve 260 axially relative to the spindle nut 230 and prevents the torque introduction sleeve 260 from moving axially as a result of the axial movement for compressing the disk spring packs 280, so that the spur toothing of the torque transmission sleeve 250 and of the torque introduction sleeve 260 no longer separates from one another

The divergence of the triggering force of the overload protection device is now determined solely by the friction in the linear movement, so that it is independent of the friction relationships in the ball screw, the transmission and the rotary clutch, and thus also independent of the type of operation "driving situation" and "back running situation", as shown in fig. 1. The divergence of the triggering force of the overload protection device is therefore differently smaller than in the case of overload protection devices according to the prior art. The disc spring pack contributes a significant portion of the friction in linear motion. Since the disk spring package is nevertheless compressed not only under the pressure load 340 but also under the tension load 360, i.e., always experiences the same direction of movement, the friction component always acts in the same direction and can be compressed when the pretensioning force of the disk spring package 280 is set. Thus, the overall friction hysteresis of the disk spring package 280, which has the divergence of the rising branches of the friction hysteresis only, does not influence the divergence of the triggering force of the overload protection device.

Another common requirement for such a control device is that damage to the control device is not permitted when driving at full travel speed relative to the control path limit inside the device. In nominal operation, such end stop travel does not occur, since the control device operates in a control loop which limits the control path. In the installation or inspection work, however, this cannot be excluded. The pre-damage that may occur from this may remain unknown and impair reliable flight operation. As can be seen from fig. 11 and 12, the requirements can also be met by means of the invention.

Fig. 11 shows the triggering of the overload function when driving in the pull-out direction to the end stop. Fig. 12 shows the same in the entry direction. At the point in time when the spindle 220 contacts the internal end stop 380 (in fig. 11) or 390 (in fig. 12), a torque builds up on the spindle nut 230, since on the one hand the drive torque is still present at the electric motor 160 and since on the other hand the sudden rotational speed change due to the blocking causes a moment of inertia which is added to the drive torque. The torque sum is converted by the ball screw 180 into a linear force that causes the associated spur tooth to disengage (in fig. 11, disengagement of the output gear 210 and torque transfer sleeve 250, and in fig. 12, disengagement of the torque transfer sleeve 250 and torque introduction sleeve 260) similar to the process described above. After disconnection, the electric motor 160 can continue to rotate until the normally present, higher-level system monitoring identifies a faulty engine rotation and disconnects the electric motor 160 from the power supply. The regulating equipment is shut down without suffering damaging load peaks.

Claims

1. An overload protection apparatus comprising:

a drive (160) for generating a rotational movement,

a conversion device (180) for converting a rotational movement into a linear movement of the adjusting element (220), and

a housing for supporting the conversion means (180),

it is characterized in that the preparation method is characterized in that,

the shifting device (180) is mounted in the housing so as to be movable along the linear movement of the adjusting element (220), the overload protection device further comprising a coupling device (210, 250, 260) for decoupling a force line between a drive (160) and the shifting device (180), wherein the coupling device (210, 250, 260) is designed to be triggered in the event of a force acting on the shifting device (180) oriented in the direction of the linear movement of the adjusting element (220) being exceeded, the coupling device (210, 250, 260) comprising an output gear (210), a torque transmission sleeve (250) and a torque introduction sleeve (260),

wherein the output gear (210) has a toothing which is directed radially outwards in order to mesh with the drive gear via an intermediate gear, or has a toothing of a bevel gear transmission and has a spur toothing in order to be able to engage with the spur toothing of the torque transmission sleeve (250), and

the torque introduction sleeve (260) has a toothing oriented radially inwards for engagement with the shifting device (180) and a spur toothing for engagement with the spur toothing of the torque transmission sleeve (250).

2. The overload protection apparatus according to claim 1,

wherein the switching device (180) is a ball screw comprising a screw nut (230), balls (240) and a screw as an adjusting element (220).

3. The overload protection apparatus according to claim 1 or 2,

wherein the output gear (210), the torque transmission sleeve (250) and the torque introduction sleeve are each arranged such that their rotational axes are oriented parallel to the linear movement of the adjusting element (220).

4. The overload protection apparatus according to claim 3,

wherein the output gear (210) is rigidly arranged on the housing with respect to the direction of the linear movement of the adjusting element and the torque transmission sleeve (250) is rigidly arranged on the conversion device (180) with respect to the direction of the linear movement of the adjusting element (220).

5. The overload protection apparatus according to claim 3,

wherein the torque introduction sleeve (260) is mounted on the switching device (180) in a manner that cannot be displaced in the direction of the linear movement of the adjusting element (220).

6. The overload protection apparatus according to claim 3,

wherein the torque introduction sleeve (260) surrounds and fixedly sets the conversion means (180) in its circumferential direction and the output gear (210) accommodates the torque introduction sleeve (260) in its circumferential direction such that a spur toothing of the output gear (210) and a spur toothing of the torque introduction sleeve (260) are simultaneously engageable with a spur toothing of the torque transmission sleeve (250).

7. Overload protection device according to claim 3, further comprising fixing means for elastically fixing the switching device (180) to the housing with respect to a direction parallel to the linear movement of the adjustment element (220).

8. Overload protection apparatus according to claim 7 wherein the fixing means has a spring element (280) in which the output gear (210) is in toothed connection with the torque transfer sleeve (250) and the torque transfer sleeve (250) is in toothed connection with the torque introduction sleeve (260) in a state of reduced stress.

9. The overload protection apparatus according to claim 8,

wherein, when the switching device (180) is moved relative to the housing in the direction of the linear movement of the adjusting element (220), the clutch device (210, 250, 260) is transferred into its open state, and the compressed or reduced compression of the spring element (280) exerts a restoring force on the switching device (180) in order to bring the clutch device (210, 250, 260) back into its closed state.

10. The overload protection apparatus according to any one of claims 8 to 9,

wherein a movement of the shifting device (180) in a direction parallel to the linear movement of the adjusting element (220) suppresses a state of reduced stress of the spring element (280) and causes a positive toothing of the output gear (210) or of the torque introduction sleeve (260) to disengage from the torque transmission sleeve (250).

11. The overload protection apparatus according to any one of claims 8 to 9,

wherein the spring element (280) is designed to exert a force on the switching device (180) in order to move the switching device such that the clutch device (210, 250, 260) is again transferred into its force-fitting state.

12. The overload protection apparatus according to any one of claims 8 to 9,

wherein the spring element (280) is arranged between the torque transmission sleeve (250) and a disc surrounding a screw nut (230) of the conversion means (180), which disc is movable in the longitudinal direction of the screw nut (230).

13. The overload protection apparatus according to claim 3,

wherein the torque introduction sleeve (260) is formed in one piece with the switching device (180), in particular with a spindle nut (230) of the switching device (180).

14. The overload protection apparatus according to claim 1,

wherein the clutch device (210, 250, 260) is disconnected not only under tension, but also under pressure.

15. The overload protection apparatus according to claim 2,

wherein the ball screw is an inverse ball screw.

16. Overload protection device according to claim 1, 5 or 6, wherein said switching means is a screw nut (230).