Spindle drive

Abstract

The disclosure relates to a spindle drive for a tailgate of a vehicle which can be adjusted between two drive end positions, in particular between a retracted position and an extended position, two drive connections being provided for diverting drive movements and a drive train between the drive connections, the drive train comprising a motor unit and a drive worm gear downstream of the motor unit in drive terms, the drive worm gear having a spindle with an external spindle drive and a spindle nut with an internal spindle nut thread which is in screw engagement with the external spindle thread, a brake assembly being provided for braking at least a part of the drive train of the spindle drive. The brake assembly can be adjustable in relation to its braking action and that the brake assembly is coupled for adjustment thereof with a component of the drive train.

Claims

1. A spindle drive for a tailgate of a motor vehicle configured to be adjusted between two drive end positions comprising a retracted position and an extended position, the spindle drive comprising: two drive connections for diverting drive movements, a drive train between the two drive connections, the drive train comprising a motor unit and a drive gear, wherein the drive gear is located downstream of the motor unit, such that the motor unit drives the drive gear, the drive gear comprising: a spindle with an external spindle thread, and a spindle nut with an internal spindle nut thread, wherein the internal spindle nut thread is in screw engagement with the external spindle thread, and a brake assembly configured to apply a braking force to at least a part of the drive train, wherein the brake force is adjustable and the brake assembly is coupled with a component of the drive train for the adjustment of the braking force, wherein the braking force increases or decreases with the adjustment of the spindle drive over at least a portion of an adjustment range of the spindle drive, and wherein the braking force depends on a position of the spindle drive.

2. The spindle drive as claimed in claim 1, wherein the brake assembly constantly brakes the drive train.

3. The spindle drive as claimed in claim 1, wherein the braking force increases at least over a portion of the adjustment range of the spindle drive with a motorized opening of the tailgate and decreases at least over a portion of the adjustment range of the spindle drive with a motorized closing of the tailgate.

4. The spindle drive as claimed in claim 3, wherein the rate of increase and the rate of decrease of the braking force relative to the adjustment of the spindle drive are identical for both adjustment directions of the spindle drive or wherein an increase and decrease of the braking force differs depending on a preceding adjustment of the spindle drive and on an adjustment direction.

5. The spindle drive as claimed in claim 1, wherein the brake assembly has an actuating element, wherein the braking force of the brake assembly can be set by an adjustment of the actuating element and the actuating element is coupled with the drive gear in such a manner that the braking force increases or decreases with an adjustment of the spindle drive at least over a portion of the adjustment range of the spindle drive.

6. The spindle drive as claimed in claim 5, wherein the brake assembly comprises a brake element and a brake counter-element which are preloaded against each other to generate the braking force via a brake spring assembly and are thereby in frictional engagement with each other.

7. The spindle drive as claimed in claim 6, wherein the brake element and the brake counter-element are part of a brake element assembly, wherein the brake element assembly is preloaded via the brake spring assembly to generate the braking force, wherein the brake element assembly has at least two brake elements and at least two brake counter-elements.

8. The spindle drive as claimed in claim 6, wherein the actuating element is coupled with the brake spring assembly in such a manner that an adjustment of the actuating element accompanies a change in the preloading of the brake element and the brake counter-element via the brake spring assembly.

9. The spindle drive as claimed in claim 6, wherein the brake element is coupled with a component of the drive train.

10. The spindle drive as claimed in claim 6, wherein the brake counter-element is coupled with a housing component of the spindle drive.

11. The spindle drive as claimed in claim 6, wherein a control gear is provided which has a spindle with an external spindle thread and a spindle nut with an internal spindle nut thread which is in screw engagement with the external spindle thread and wherein the actuating element is coupled with the drive gear via the control gear, wherein the spindle of the drive gear is coupled with the spindle of the control gear, and wherein the actuating element is coupled with the spindle nut of the control gear or forms the spindle nut of the control gear.

12. The spindle drive as claimed in claim 11, wherein the control gear comprises at least one freewheel mechanism configured in such a manner that an adjustment of the spindle drive into at least one drive end position results in the control gear freewheeling when a freewheel end region upstream of the respective drive end position is passed through or wherein the control gear comprises two freewheel mechanisms configured in such a manner that an adjustment of the spindle drive into the two drive end positions results in each case in the control gear freewheeling when a freewheel end region upstream of the respective drive end position is passed through.

13. The spindle drive as claimed in claim 12, wherein at least one of the freewheel mechanisms is formed such that when a freewheel end region is reached, the spindle nut of the control gear comes out of engagement with the spindle thereof, wherein the spindle of the control gear has fewer threads than the spindle of the drive gear.

14. The spindle drive as claimed in claim 11, wherein a spring assembly of the brake assembly is coupled with the actuating element in such a manner that the spring assembly constantly preloads the spindle nut of the control gear into engagement with the spindle of the control gear.

15. The spindle drive as claimed in claim 11, wherein the brake spring assembly has a first spring component and a second spring component which act against one another, at least over a portion of the adjustment range of the spindle drive, to generate the preloading of a brake element assembly, wherein a spring force of the first spring component helps to preload the brake element assembly at least over a portion of the adjustment range of the spindle drive and a spring force of the second spring component reduces the preloading of the brake element assembly.

16. The spindle drive as claimed in claim 15, wherein a magnitude of the preloading of the brake element assembly results from a difference between the magnitudes of the spring forces of the two spring components.

17. The spindle drive as claimed in claim 15, wherein the two spring components are arranged along the longitudinal axis of the spindle drive on opposite sides of the brake element assembly.

18. The spindle drive as claimed in claim 15, wherein both spring components of the brake spring assembly apply a force, in opposite directions, on the same element of the brake spring assembly.

19. The spindle drive as claimed in claim 15, wherein an axial stop is provided for the brake element assembly and the first spring component exerts a spring force on the brake element assembly in a direction of the axial stop, wherein the second spring component exerts a spring force on the brake element assembly in the opposite direction.

20. The spindle drive as claimed in claim 15, wherein the spring force of the first spring component acting on the brake element assembly is constant, irrespective of the adjustment of the spindle drive, at least over a portion of the adjustment range of the spindle drive.

21. The spindle drive as claimed in claim 15, wherein the first spring component or the second spring component of the brake spring assembly, for adjustment of the braking force is coupled with the actuating element, wherein the brake spring assembly is in engagement with, or becomes engaged with, the actuating element depending on the adjustment of the spindle drive for setting the braking force.

22. The spindle drive as claimed in claim 15, wherein the first spring component or the second spring component of the brake spring assembly, for adjustment of the braking force is coupled with the spindle nut of the control gear, wherein the brake spring assembly is in engagement with, or becomes engaged with the spindle nut of the drive gear depending on the adjustment of the spindle drive for setting the braking force.

23. The spindle drive as claimed in claim 5, wherein an adjustment of the spindle drive between the two drive end positions accompanies an adjustment of the actuating element between two actuating element end positions.

24. A tailgate assembly of a motor vehicle with a tailgate and with the spindle drive for the motorized adjustment of the tailgate as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the teachings of this disclosure are explained in greater detail with the help of drawings depicting various embodiments. In the drawings,

(2) FIG. 1 shows as a schematic side view the tail of a motor vehicle with a spindle drive as proposed,

(3) FIG. 2 shows a detail of the spindle drive according to FIG. 1 a) relating to the brake assembly with the tailgate in the closed position and b) with the tailgate in the open position,

(4) FIG. 3 shows the profile of the braking action of the brake assembly of the spindle drive according to FIG. 1 in relation to the position of the spindle drive,

(5) FIG. 4 shows a further embodiment of the spindle drive according to FIG. 1 as a view according to FIG. 2,

(6) FIG. 5 shows the profile of the braking action of the brake assembly of the spindle drive according to FIG. 4 in relation to the adjustment of the spindle drive,

(7) FIG. 6 shows a further embodiment of the spindle drive according to FIG. 1 as a view according to FIG. 2, a) with the tailgate in the closed position and b) with the tailgate in a slightly open position,

(8) FIG. 7 shows a further embodiment of the spindle drive according to FIG. 1 as a view according to FIG. 6, and

(9) FIG. 8 shows the brake package of the spindle drive according to FIG. 7 a) with two brake elements and b) with three brake elements.

DETAILED DESCRIPTION

(10) The spindle drive 1 depicted in drawing is used for the motorized adjustment of a tailgate 2 of a motor vehicle which in this case is configured as a tailgate. Reference may be made to the broad interpretation of the term “tailgate” as mentioned above.

(11) The tailgate 2 is used in a customary manner per se to close a tailgate opening 3. The spindle drive 1 is arranged in this respect to the side of the tailgate opening 3, here in a rain gutter 4 arranged to the side of the tailgate opening 3. Although FIG. 1 only shows a single spindle drive 1, it is provided in this case that a spindle drive 1 is arranged on either side of the tailgate opening 3. The two spindle drives 1 are substantially identical in design structurally speaking.

(12) It can be seen from the representation according to FIG. 1 that the spindle drive 1 depicted there is hinged to the body 5 of the motor vehicle at one end and to the tailgate 2 at the other end.

(13) The spindle drive 1 can be adjusted between two drive end positions which define the adjustment range of the spindle drive 1 in the present case. In turn, different advantageous variants are conceivable for defining the drive end positions. In this case, the drive end positions are positions of the spindle drive 1 which correspond to the open position and the closed position of the tailgate 2 in the mounted state of the spindle drive 1.

(14) The spindle drive 1 is adjustable between a retracted position S.sub.e and an extended position S.sub.a which defines the adjustment range of the spindle drive 1 in the present case. In this case, the retracted position S.sub.e corresponds to the closed position of the tailgate 2, while the extended position S.sub.a corresponds to the open position of the tailgate 2. FIG. 1 shows the tailgate 2 in the open position. In the detail representation shown there, the spindle drive 1 is only shown in the retracted position S.sub.e so that a better overview is provided.

(15) The spindle drive 1 has two drive connections 6, 7 for diverting drive movements and also a drive train 8 between the drive connections 6, 7. The drive train 8 comprises a motor unit 9 and also a drive worm gear 10 downstream of the motor unit 9 in drive terms. Driven by the motor unit 9, the drive worm gear 10 produces the drive movements which are predominantly linear drive movements in the present case.

(16) The drive worm gear 10 is a spindle drive which has a spindle 11 with an external spindle thread and a spindle nut 12 with an internal spindle nut thread which is in screw engagement with the external spindle thread.

(17) The spindle drive 1 is assigned a brake assembly 13 for braking at least part of the drive train 8 of the spindle drive 1. The brake assembly 13 therefore performs a braking action on the part of the drive train 8 concerned. The braking action may be a braking torque or a braking force which acts on any component of the drive train 8. The braking action to be broadly interpreted in accordance with the concept is indicated in FIGS. 3 and 5 using the reference number B.

(18) The brake assembly 13 can be used to hold the tailgate 2 in the open position depicted in FIG. 1, particularly in the event that the spindle drive 1 is switched off. In this case it is provided in this respect that the holding of the tailgate 2 is supported by a spring arrangement 14 which, as depicted in FIG. 1, acts between the two drive connections 6, 7.

(19) The brake assembly 13 is adjustable in respect of the braking action B thereof, wherein the brake assembly 13 is coupled with a component 15 of the drive train 8 for the setting thereof. This means quite generally that the braking action B of the brake assembly 13 can be set by adjusting the appropriate component 15 of the drive train 8. Depending on the structural embodiment of the brake assembly 13, a different braking action B performance can be produced depending on the position S of the spindle drive 1, as can be inferred from the representations according to FIGS. 3 and 5.

(20) FIGS. 3 and 5 firstly show the braking action B as a dotted line as a function of the position S of the spindle drive 1 for embodiments according to FIGS. 2 and 4. In this case, braking actions B in the opposite direction result between an opening movement 16 and a closing movement 17 of the tailgate 2 due to the reverse movement. The assignment of the respective braking action B to the respective movement of the tailgate 2 is indicated in FIGS. 3 and 5 using arrows 16, 17.

(21) In both exemplary embodiments depicted, the brake assembly 13 constantly brakes the drive train 8 of the spindle drive 1. However, it is also fundamentally conceivable for the brake assembly 13 to be uncoupled from the drive train 8.

(22) Furthermore, it can be inferred from the representations according to FIGS. 3 and 5 that the braking action B rises or falls with the adjustment of the spindle drive 1, in this case linearly, at least over a portion of the adjustment range of the spindle drive 1. In this respect it is provided in various exemplary embodiments that the braking action B rises at least over a portion of the adjustment range of the spindle drive 1 with the motorized opening of the tailgate 2 and falls at least over a portion of the adjustment range of the spindle drive 1 with the motorized closing of the tailgate 2. This is also appropriate, since the braking action B is primarily required to hold the tailgate 2 in the open position or in an intermediate position, while the braking action B of the brake assembly 13 has a more disruptive influence in the region of the closing position of the tailgate 2.

(23) In principle, the profile of the braking action B during the opening movement 16 may be provided symmetrically to the profile of the braking action B during the closing movement 17, as is shown in FIG. 3. It may also be advantageous, however, for the corresponding profiles of the braking action B of the brake assembly 13 to be designed asymmetrically to one another, as is shown in FIG. 5.

(24) FIGS. 3 and 5 show that the rate of increase or rate of reduction of the braking action B relative to the adjustment of the spindle drive 1 there is constantly identical for both adjustment directions. This means, in the mathematical sense, that the gradient of the profile of the braking action B is constantly identical in terms of magnitude, insofar as in the respective portion of the adjustment range of the spindle drive 1 there is in fact any increase in the braking action.

(25) With the embodiment according to FIG. 5, it is true that the braking action B remains constant over at least a portion of the adjustment range of the spindle drive 1. This is provided, particularly in the region of a drive end position, especially in the region of the drive end position corresponding to the open position of the tailgate 2.

(26) The design according to FIG. 5 shows a special feature to this extent, in that the profile of the braking action B during an opening movement 16 with a subsequent closing movement 17 is hysteresis-like. This means that the rise or fall of the braking action B differs depending on the preceding adjustment of the spindle drive 1 or on the adjustment direction. The implementation in this respect is explained in detail below.

(27) The brake assemblies 13 depicted in FIGS. 2 and 4 are each fitted with an actuating element 18, wherein the braking action B of the brake assembly 13 can be set by an adjustment of the actuating element 18. The actuating element 18 for this purpose is coupled with the drive worm gear 10, in this case with the spindle 11 of the drive worm gear 10, in such a manner that the braking action B rises or falls with the adjustment of the spindle drive 1 at least over a portion of the adjustment range of the spindle drive 1. The coupling of the actuating element 18 with the drive worm gear 10 will be explained below.

(28) In this case, the brake assembly 13 is fitted with a brake element 19 and a brake counter-element 20, wherein the brake element 19 and brake counter-element 20 are preloaded in respect of one another to generate the braking action B via a brake spring assembly 21 and are thereby in frictional engagement with one another.

(29) In this case it is further provided that the actuating element 18 is coupled with the brake spring assembly 21, namely in such a manner that an adjustment of the actuating element 18 accompanies a change in the spring preloading. This results in each case from an integrated view of FIGS. 2a and 2b and also of FIGS. 4a and 4b.

(30) It is quite generally true that the brake element 19 and the brake counter-element 20 are integral parts of a brake package P which is preloaded via the brake spring assembly 21 to generate the braking action. The brake package P can have at least two brake elements 19a-c and/or at least two brake counter-elements 20a-c. In this case, the brake elements 19a-c and the brake counter-elements 20a-c are axially coated so that the preloading to generate the braking action B produces a frictional engagement between each adjacent brake element 19a-c and brake counter-element 20a-c. FIG. 8a shows by way of example a brake package P made up of two brake elements 19a-c and two brake counter-elements 20a-c, while FIG. 8b shows by way of example a brake package P made up of three brake elements 19a-c and three brake counter-elements 20a-c.

(31) In order to generate the desired braking action B, the brake element 19 is coupled with the component 22 of the drive train 8 to be braked, in this case with a drive shaft of the drive train 8. The exemplary embodiment depicted in the case of this coupling is a non-rotational coupling between the brake element 19 and the component 22. In this case, the brake element 19 is at least slightly displaceable along the longitudinal axis 1a of the spindle drive 1, so that the brake element 19, as shown in the drawing, can be aligned between an upper brake counter-element 20a and a lower brake counter-element 20b.

(32) The brake counter-element 20, in this case the upper brake counter-element 20a, and the lower brake counter-element 20b, is/are coupled with a housing component 23. In this case, the lower brake counter-element 20b is connected to the housing component 23, while the upper brake counter-element 20a is non-rotational relative to the longitudinal axis 1a, but is coupled in a longitudinally displaceable manner with the housing component 23.

(33) What is interesting is that in addition to the drive worm gear 10, a control worm gear 24 is provided which has a spindle 25 with an external spindle thread and a spindle nut 26 with an internal spindle thread which is in screw engagement with the external spindle thread. In this case, the actuating element 18 is coupled via the control worm gear 24 with the drive worm gear 10, in that the spindle 11 of the drive worm gear 10 can be coupled with, in this case connected to, the spindle 25 of the control worm gear 24. This is shown in FIGS. 2 and 4, in which in the respective representation the spindle 11 of the drive worm gear 10 projects upwards and the drive shaft 9a of the motor unit 9 downwards.

(34) In various embodiments, the actuating element 18 is coupled with the spindle nut 26 of the control worm gear 24. In this case it is even the case that the actuating element 18 forms the spindle nut 26 of the control worm gear 24. This means that a rotation of the spindle 11 of the drive worm gear 10 brings with it a corresponding adjustment of the actuating element 18, at least over a portion of the adjustment range of the spindle drive 1. Specifically, it is the case that an adjustment of the spindle drive 1 between the two drive end positions accompanies an adjustment of the actuating element 18 between two actuating element end positions.

(35) For the first exemplary embodiment, FIGS. 2a and 2b show the actuating element 18 in the two actuating element end positions, wherein FIG. 2a corresponds to the closed position of the tailgate 2 and FIG. 2b to the open position of the tailgate 2. An overall view of FIGS. 2a and 2b shows that the actuating element 18 is always engaged with the spindle 25 of the control worm gear 24 during the adjustment of the tailgate 2 between the closed position and the open position. This produces the performance of the braking action B of the brake assembly 13 shown in FIG. 3 results.

(36) A different method of operation results in the exemplary embodiment according to FIG. 4. The control worm gear 24 is fitted in this respect with at least one freewheel, in this case with two freewheels 27, 28. An adjustment of the spindle drive 1 into the drive end positions results in the control worm gear 24 freewheeling when a freewheel end region upstream of the respective drive end position is passed through. The freewheel end regions are depicted in FIG. 5 using the reference numbers 29, 30. “Freewheeling of the control worm gear” in the present case means that an adjustment of the control worm gear 24, in particular of the spindle 25 of the control worm gear 24, does not trigger an adjustment of the actuating element 18 and therefore a change in the braking action B. This can be seen most clearly from the depiction according to FIG. 5.

(37) The freewheels 27, 28 are formed in this case in that the spindle 25 of the control worm gear 24 for each freewheel 27, 28 has a corresponding cutout 31, 32 in the external spindle thread of the spindle 25 of the control worm gear 24.

(38) In addition, it can be provided that the spindle 25 of the control worm gear 24 has fewer threads than the spindle 11 of the drive worm gear 10. Insofar as the spindle 11 of the drive screw worm 10, as shown in the drawing, is coupled with, in particular connected to, the spindle 25 of the control worm gear 24, this means with a suitable design that an adjustment of the spindle drive 1 between the two drive end positions accompanies a passing through of the two freewheel end regions 29, 30. The fact that when a freewheel end region 29, 30 is reached, the spindle nut 26 of the control worm gear 24 comes out of engagement with the spindle 25 thereof, means that the braking action B remains constant in each case during the passing through of the freewheel end regions 29, 30.

(39) In order to ensure that even with a motorized opening of the tailgate 2 from the closed position, a “threading” of the spindle nut 26 onto the spindle 25 of the control worm gear 24 takes place safely, a further spring assembly 33 is provided which is coupled with the actuating element 18 in such a manner that the spring assembly 33 constantly preloads the spindle nut 26 of the control worm gear 24 in engagement with the spindle 25 thereof. This can be seen most clearly from the depiction in FIG. 4a. FIG. 4b shows that the same function is assigned to the brake spring assembly 21 with motorized closure of the tailgate 2 from the open position.

(40) It should also be pointed out that FIG. 5 used a dotted line to depict the profile of the braking action B of the brake assembly 13 of the spindle drive 1 according to FIG. 4 in a further embodiment, in which the gap S between the actuating element 18 and the brake spring assembly 21 has been enlarged. The gap S means that a motorized closure from the closing position is initially accompanied by an adjustment portion of constant or diminishing braking action. This is due to the fact that in this portion the brake spring assembly 21 is still disengaged from the actuating element 18.

(41) The brake assembly 13 as proposed may be arranged at completely different points of the drive train 8 of the spindle drive 1. For example, it is conceivable for the brake assembly 13 to be integrated in an overload coupling connected in the drive train 8. Alternatively, it may be provided that the brake arrangement 13 is integrated in the spindle nut 12 of the drive worm screw 10.

(42) FIGS. 6 and 7 show two further embodiments in which the brake spring assembly 21 has a first spring component 21a and a second spring component 21b which work against one another, at least over a portion of the adjustment range of the spindle drive 1, when it comes to generating the preloading of the brake packet P. What is meant by this is that the spring forces of the two spring components 21a, 21b more or less offset one another when it comes to generating the preloading of the brake package P depending on the adjustment of the spindle drive 1, as will be shown. The spring components 21a and 21b in this case are helical spring elements which are each oriented coaxially to the longitudinal axis 1a of the spindle drive 1. In principle, each spring component 21a, 21b may also have a plurality of helical spring elements. The spring characteristics of the two spring components 21a, 21b, in particular the effective spring characteristic lines in each case, are in this case identical to one another.

(43) The spring components 21a, 21b in the exemplary embodiments which are shown in FIGS. 6 and 7 and are coupled directly or indirectly with the brake package P, in such a manner that at least over a portion of the adjustment range of the spindle drive 1, the spring force of the first spring component 21a helps to preload the brake package P and the spring force of the second spring component 21b reduces the preloading of the brake package P. Specifically, it is true that the magnitude of the preloading of the brake package P results from the difference between the magnitudes of the spring forces of the two spring components 21a, 21b. For this purpose, the two spring components 21a, 21b are arranged along the longitudinal axis 1a of the spindle drive 1 on opposite sides of the brake package P.

(44) At least part of the brake package P can be displaceable at least slightly axially, so along the longitudinal axis 1a of the spindle drive 1. In the case of the exemplary embodiments depicted and the entire brake package P in each case is at least slightly axially displaceable. In this case the brake elements 19 are each coupled in a non-rotational manner with the spindle 11 of the drive worm gear 10, while the brake counter-elements 20 are each coupled in a non-rotational manner with the housing component 23.

(45) So that they work against one another in the above sense, the spring components 21a, 21b of the brake spring assembly 21 may in principle be directly engaged with one another. In this case, it is however true that both spring components 21a, 21b of the brake spring assembly 21 work against one another on one and the same element of the brake spring assembly 21, in this case on the brake counter-element 20 or on the brake counter-element 20a. In order to achieve this, at least part of the brake package P is arranged in a bell body 35 which is in engagement with, or can be brought into engagement with, a brake counter-element 20 of the brake package P at one end and with the second spring component 21b at the other end. This may, in principle, also be provided for a brake element 19.

(46) FIGS. 6 and 7 show that an axial stop 36, relative to the longitudinal axis 1a, is provided for the axially displaceable brake package P and that the first spring component 21a exerts a spring force on the brake package P in the direction of the axial stop 36. The second spring component 21b, on the other hand, exerts a spring force on the brake package P against the direction of the axial stop 36. The axial stop 36 may, in principle, also assume the function of a brake element 19 or a brake counter-element 20 which is fixed on the housing component 23 or on the spindle 11.

(47) Further, the spring force of the first spring component 21a acting on the brake package P is constant, irrespective of the adjustment of the spindle drive 1, at least over a portion of the adjustment range of the spindle drive 1. This is the case when the influence of the second spring component 21b on the resulting preloading of the brake package P is negligibly small. In the situation shown in FIG. 7b, this is the case since the second spring component 21b is disengaged from the brake package P there.

(48) With the exemplary embodiment shown in FIG. 6, a spring component 21a, 21b of the brake spring assembly 21, in particular the second spring component 21b, for adjustment of the braking action is coupled with the actuating element 18 of the control worm gear 24. This means that the spring force of the second spring component 21b works against the spring force of the second spring component 21a, in this case via the bell body 35, depending on the adjustment of the spindle drive 1. In the situation shown in FIG. 6a, the tailgate 2 is in the closed position in which the actuating element 18 is in a lower position in FIG. 6. This means that the second spring component 21b acts with a high spring force on the brake counter-element 20, so that the brake counter-element 20 is triggered by the brake element 19 and the braking action is cancelled. With the motorized opening of the tailgate 2, the actuating element 18 reaches the position shown in FIG. 6b, which reduces the spring force of the second spring component 21b, so that due to the spring force of the first spring component 21a, a preloading of the brake package P is generated. To be precise, this preloading, as indicated above, results from the difference between the magnitudes of the spring forces of the two spring components 21a, 21b.

(49) A fundamentally similar method of operation during production of the braking action is shown by the arrangement according to FIG. 7. In this case, a spring component 21a, 21b of the brake spring assembly 21, in particular the second spring component 21b, is coupled for adjustment of the braking action with the spindle nut 12 of the drive worm gear 10. In this case, it can be true that the brake spring assembly 21 is in engagement with, or becomes engaged with, the spindle nut 12 of the drive worm gear 10, depending on the adjustment of the spindle drive 1 for adjusting the braking action. The spindle nut 12 creates the actuating element referred to above to this extent, so that a separate control worm gear can be dispensed with.

(50) According to further teaching, the tailgate assembly 34 of the motor vehicle is disclosed as such with the tailgate 2 and with a spindle drive 1 as proposed, which spindle drive is used for the motorized adjustment of the tailgate 2. Reference may be made to all comments on the spindle drive 1 as proposed.