Spindle drive for a locking element of a motor vehicle

Description

[0001] The present invention relates to a spindle drive for a closure element of a motor vehicle according to the preamble of claim 1.

[0002] The spindle drive in question can be associated with any closure element of a motor vehicle. This includes tailgates, trunk lids, rear doors, side doors, or the like. In this respect, the term "closure element" is to be understood broadly.

[0003] The known spindle drive (DE 10 2017 117 993 A1), from which the invention is based, has the usual structural design with a spindle-spindle nut gear, wherein a drive motor is also provided, downstream of which the spindle-spindle nut gear is connected. A spindle-side drive section, which has the drive spindle of the spindle-spindle nut gear and, in this case, the drive motor, downstream of which the spindle is connected, and a spindle-nut-side drive section, which has the spindle nut of the spindle-spindle nut gear, are provided. The two drive sections can be adjusted relative to one another, in this case by motor, and are each connected to a drive connection for coupling to the motor vehicle and, in this case, for transmitting the resulting linear drive movements.The known spindle drive further comprises a spindle drive housing with an inner tube associated with the spindle nut-side drive section and an outer tube associated with the spindle-side drive section. The outer tube has an annular sealing arrangement that runs circumferentially relative to the geometric spindle axis and slides along the inner tube during the execution of the drive movements.

[0004] The proposed sealing arrangement allows for effective sealing of the spindle drive's interior against ambient fluids, such as rain or splash water. However, reducing friction-related wear of the sealing arrangement and friction-related noise is a challenge.

[0005] The invention is based on the problem of designing and developing the known spindle drive in such a way that an optimization of the sealing arrangement with regard to wear and noise generation is achieved.

[0006] The above problem is solved by the features of the characterising part of claim 1.

[0007] The key idea is to partially lift the sealing arrangement slightly from the pipe along which it slides, for example the inner pipe, during linear drive movements of the spindle drive between its retracted position and its extended position, preferably during the majority of the relative movement of the outer pipe with respect to the inner pipe. This reduces the friction between the sealing arrangement and the pipe that occurs during the relative movement. For this purpose, the sealing arrangement is divided axially into two ring sections, one of which can be radially deflected, for example spread open, during the relative movement through the pipe along which the sealing arrangement is guided, for example the inner pipe, whereby the radial pressure force of this ring section during the relative movement can be reduced compared to that in the retracted position.In the retracted position, however, the ring section is not deflected and seals particularly effectively.

[0008] It should be emphasized that, instead of the inner tube, the outer tube can also form the tube along which the sealing arrangement slides. In this case, the outer tube would deflect the said ring section radially inward during the above relative movement, for example, radially narrow it to reduce the radial contact force. While the following refers to the first variant above, in which the sealing arrangement is fixed to the outer tube and slides along the outside of the inner tube, the explanations for the latter variant, in which the sealing arrangement is fixed to the inner tube and slides along the inside of the outer tube, apply accordingly.

[0009] In detail, it is proposed that the sealing arrangement has a first axial ring section and a second axial ring section which is axially adjacent to it with respect to the geometric spindle axis and is movably, in particular pivotably, connected to the first axial ring section, and that when the drive movements are carried out, the second axial ring section is radially displaceable, in particular pivotable, relative to the first axial ring section between a sealing position in which a sealing effect of the sealing arrangement is greatest and a lifting position in which the sealing effect of the sealing arrangement is less than in the sealing position.

[0010] Regarding claim 2, it is noted that the radial displacement of the second axial ring section between the sealing position and the lifting position occurs automatically during drive movements of the spindle drive, so that no separate mechanism is necessary for this purpose.

[0011] Regarding claim 3, it is noted that the axial sealing section is thus displaced during the radial displacement of the second ring section. This sealing section can also have a sealing lip, which preferably no longer touches the respective pipe in the lift-off position.

[0012] Claim 4 defines several circumferential segments arranged side by side, forming the second axial ring section, each of which is displaceable or pivotable. "Each displaceable" means that each circumferential segment is displaceable independently of the adjacent circumferential segment. The circumferential segments can be circumferentially separated from one another, but can also be elastically connected to one another, whereby the circumferential segments themselves are less elastic than the connection between them. In this way, a radial displacement of the second axial ring section or sealing section can be achieved particularly efficiently.

[0013] Claims 5 and 6 define particularly preferred materials for the first and / or second axial ring section and / or the circumferential segments. A combination of a hard component and a soft component, i.e., two materials that differ in their elasticity and / or Shore hardness, is particularly preferred. The hard component then serves, in particular, as a functional carrier, while the soft component serves for the sealing function.

[0014] Regarding claim 7, it is noted that the webs can also be circumferentially spaced from each other in the sealing position and / or in the lifting position. This allows for particularly easy radial movements.

[0015] Claim 8 defines an axial contact section of the second axial ring section and / or the circumferential segments, which interacts with contact ribs of a running section of the tube along which the annular sealing arrangement slides. Upon contact, the contact section is pushed away from the contact ribs, causing the second axial ring section and / or the circumferential segments to move radially, for example radially outward, into the lift-off position. Adjacent to the contact section is a rib-free sealing section in which the contact section is not pushed away, so that the second axial ring section and / or the circumferential segments remain in the sealing position or move into the sealing position.

[0016] Regarding claim 9, it is noted that the webs thus have a profile with an axial and a circumferential directional component. This ensures that even with larger gaps between circumferentially adjacent webs, the circumferential segments can always optimally contact the contact ribs.

[0017] Preferred connection possibilities for fixing the sealing arrangement to the respective pipe, for example outer pipe, are the subject of claim 12.

[0018] Regarding claim 15, it is noted that the drive unit with the drive motor can generate a motor drive force acting on the two drive sections. Furthermore, it is noted that, alternatively or additionally, at least one helical spring is arranged within the inner tube, which pretensions the two drive sections against each other, so that a corresponding spring force, in particular compressive force, can effect or at least assist an adjustment of the spindle drive as a drive force. In particular, the optional drive motor can be assisted by the spring force when adjusting the spindle drive, especially when extending a heavy tailgate as a closure element.

[0019] Regarding claim 16, it is noted that in this way the essential components of the spindle drive are optimally protected.

[0020] In the following, the invention is explained in more detail with reference to a drawing which merely illustrates exemplary embodiments. In the drawing, Fig. 1 the rear area of ​​a motor vehicle with a proposed spindle drive for the closure element there, Fig. 2 a side sectional view of the spindle drive according to Fig. 1 in the a) retracted position and b) extended position, Fig. 3 different views of a sealing arrangement of the spindle drive according to Fig. 1 with a ring section of the sealing arrangement in a sealing position and Fig. 4 different views of the sealing arrangement according to Fig. 3 with the ring section in a lift-off position.

[0021] The Fig.1 The spindle drive 1 shown is a component of a closure element assembly 2 with a closure element 3 of a motor vehicle. The term "closure element 3" is to be understood broadly in this case, as explained in the introductory part of the description. In this case, the closure element 3 is the tailgate of a motor vehicle.

[0022] All relevant statements apply accordingly to all other types of closure elements 3.

[0023] The spindle drive 1 has a Fig. 2 The spindle-spindle nut drive 4 shown here is used to carry out or generate linear drive movements. The spindle-spindle nut drive 4 is equipped in the usual way with a spindle 4a and a spindle nut 4b meshing with the spindle 4a. In the embodiment of a spindle drive 1 shown here, the spindle 4a is motor-driven, while the spindle nut 4b is secured against rotation and therefore performs a linear drive movement depending on the adjustment of the spindle 4a.

[0024] A spindle-side drive section 5 of the spindle drive 1 has at least one spindle 4a of the spindle-spindle nut gear 4, as well as, preferably, a drive unit 6 with a drive motor 7, in particular an electric one, to which the spindle 4a is connected downstream. The term "downstream" in this case always means that the downstream component is mechanically coupled to the upstream component.

[0025] It should be emphasized that the proposed spindle drive 1 can also dispense with the above-mentioned drive unit with a drive motor. In this case, one also refers to the so-called passive side of the closure element arrangement 2. In the exemplary embodiment, however, a drive unit 6 with a drive motor 7 is provided, which is then referred to as the so-called active side of the closure element arrangement 2. The closure element arrangement 2 can, in principle, have only one (active) or the other (passive) spindle drive type, or a combination of both spindle drive types.

[0026] A spindle nut-side drive section 8 of the spindle drive 1 has at least the spindle nut 4b of the spindle-spindle nut gear 4.

[0027] When the optional drive motor 7 is actuated, a linear adjustment of the two drive sections 5, 8 occurs. In order to couple the drive sections 5, 8 to the motor vehicle and to transmit the motor-generated linear drive movements, the spindle-side drive section 5 is equipped with a spindle-side drive connection 9, and the spindle-nut-side drive section 8 is equipped with a spindle-nut-side drive connection 10. The drive connections 9, 10 are here and preferably designed as ball sockets, which, when installed, each engage with ball heads on the motor vehicle. Other types of drive connections are conceivable.

[0028] As shown in the illustration Fig. 2 As can be seen, the spindle-spindle nut gear 4 and the optional drive unit 6 are arranged one behind the other along the geometric spindle axis 11. This applies here and preferably also to the drive connections 9, 10, which are also arranged on the geometric spindle axis 11.

[0029] In order to protect the interior 12 of the spindle drive 1 against external influences, a spindle drive housing 13 with an inner tube 14 and an outer tube 15 is provided, wherein the inner tube 14 runs telescopically in the outer tube 15.

[0030] The inner tube 14 is connected to the spindle nut side drive section 8, while the outer tube 15 is connected to the spindle side drive section 5.

[0031] In the interior 12 of the spindle drive 1, at least one helical spring 16 is provided here and preferably. Specifically, a helical spring 16 is arranged within the inner tube 14 coaxially to the geometric spindle axis 11, which prestresses the two drive sections 5, 8 against each other. Here and preferably, the helical spring 16 biases the two drive sections 5, 8 into the Fig. 2b ) shown. This can also be reversed. The coil spring 16 is here and preferably designed as a helical compression spring.

[0032] In the Fig. 2 In the illustrated embodiment, only one helical spring 16 is assigned to the spindle drive 1. In principle, however, two or more helical springs 16 can also be provided, each of which is aligned coaxially with the geometric spindle axis 11.

[0033] It should also be emphasized that a torsion tube 17 extends within the at least one helical spring 16 and is fixed at one end to the spindle-side drive section 5. The torsion tube 17 functions, on the one hand, as a spring guide tube that supports the helical spring 16 in the radial direction relative to the geometric spindle axis 11 in such a way that a corresponding radial deflection of the helical spring 16 is prevented. However, the torsion tube 17 is also part of an anti-twist device for the spindle nut 4b, which can only be moved axially on the torsion tube 17.

[0034] According to the illustration Fig. 2 It can also be seen that the spindle nut 4b is connected to the spindle nut-side drive connection 10 via a spindle nut tube 18.

[0035] It is also noteworthy that the torsion tube 17 is fixed at one of its ends, here at the spindle-side end 17a, to the spindle-side drive section 5. This means that the torsion tube 17 is fixed with respect to the linear adjustment of the spindle-nut-side drive section 8 and thus of the inner tube 14. Thus, the free end 19 of the inner tube 14, which faces away from the spindle-nut-side drive connection 10, runs along the torsion tube 17.

[0036] Here and preferably, the spindle drive housing 13 radially surrounds the spindle-spindle nut gear 4, the drive motor 7, the torsion tube 17, the spindle nut tube 18 and / or the at least one helical spring 16, in particular over its entire axial extent.

[0037] To seal the interior 12 of the spindle drive 1 against the ingress of moisture, the outer tube 15, or according to an alternative not shown, the inner tube 14, has an annular sealing arrangement 20 which runs circumferentially with respect to the geometric spindle axis 11 and which slides along the other tube, in this case the inner tube 14, of the spindle drive housing 13 during the execution of the drive movements.

[0038] It is now essential that the sealing arrangement 20 has a first axial ring section 21 and a second axial ring section 22 which is axially adjacent to it with respect to the geometric spindle axis 11 and is movably, in particular pivotably, connected to the first axial ring section 21, and that when the drive movements are carried out, the second axial ring section 22 is radially displaceable, in particular pivotable, relative to the first axial ring section 21 between a sealing position in which a sealing effect of the sealing arrangement 20 is at its greatest, and a lifting position in which the sealing effect of the sealing arrangement 20 is less than in the sealing position.

[0039] Furthermore, it is preferably provided here that an axial relative movement of the outer tube 15 relative to the inner tube 14 causes the radial displacement, in particular pivoting, of the second axial ring section 22 between the sealing position and the lifting position. The displacement thus occurs automatically through the drive movements of the spindle drive 1.

[0040] As the Fig. 3 and 4show, here and preferably the second axial ring section 22 has an axial sealing section 23, which in the sealing position is pressed against the respective tube of the spindle drive housing 13 with a greater radial pressure force than in the lifting position. Here and preferably the axial sealing section 23 has a circumferential sealing lip 24 with respect to the geometric spindle axis 11, which in the sealing position is pressed against the respective tube, here the inner tube 14, of the spindle drive housing 13 with a greater radial pressure force than in the lifting position.

[0041] For displacing, in particular pivoting, the second axial ring section 22 between the sealing position and the lifting position, here and preferably the second axial ring section 22 is formed by several circumferentially arranged circumferential segments 25, which are each displaceable, in particular pivotable about a geometric pivot axis tangential to the geometric spindle axis 11. The displaced or pivoted state is shown in Fig. 4 .

[0042] Furthermore, it is preferably provided here that the first axial ring section 21 and / or the second axial ring section 22 and / or the circumferential segments 25 are each formed from a hard component 26 and a soft component 27, which together form a one-piece, two-component injection-molded part. The sealing lip 24 is also formed here by the soft component 27.

[0043] The terms "hard component" and "soft component" here mean that the material of the components differs significantly in its elasticity and / or Shore hardness, i.e., the modulus of elasticity differs by at least 100 N / mm 2 , preferably by at least 250 N / mm 2 , more preferably by at least 500 N / mm 2 . A hard component is formed from a less elastic material, in particular plastic material, than a soft component. A hard component here and preferably means a component, in particular a plastic part, that has a modulus of elasticity of at least 1000 N / mm 2 and / or a Shore A hardness of at least 95, preferably at least 100, and / or a Shore C hardness of at least 45, preferably at least 70.A soft component here is and preferably a component, in particular a plastic part, with a modulus of elasticity of at most 500 N / mm 2 and / or a Shore A hardness of at most 85, preferably at most 75, and / or a Shore C hardness of at most 30, preferably at most 25.

[0044] In the embodiment illustrated here, the hard component 26 is formed from a metal or a plastic material, in particular a glass fiber-reinforced plastic material or polyamide. Additionally or alternatively, as here, the soft component 27 can be formed from a permanently elastic plastic material, in particular an elastomer, preferably a thermoplastic elastomer defined according to DIN EN ISO 18064, ISO 18064, or liquid silicone (Liquid Silicone Rubber, LSR).

[0045] The Fig. 3b ) and 4b) further show that here and preferably the hard component 26 has a plurality of circumferentially separated webs 28. These are here and preferably embedded in the soft component 27 or the soft component 27 is applied to the webs 28, for example, by injection molding. Here and preferably the soft component 27 is arranged circumferentially without interruption relative to the geometric spindle axis 11, thus connecting the webs 28 to one another in the circumferential direction.

[0046] Here, and preferably, the second axial ring section 22 and / or the circumferential segments 25 each have an axial contact section 29 which, relative to the first axial ring section 21 and / or the geometric pivot axes, projects radially toward the tube, here inner tube 14, of the spindle drive housing 13, along which the annular sealing arrangement 20 slides when performing the drive movements. The tube toward which the axial contact section 29 projects, here inner tube 14, also has an axial contact section 30 for sealing contact of the sealing section 23 and an adjacent axial running section 31 which has axially extending contact ribs 32 projecting radially relative to the axial contact section 30. Here, and preferably, the axial contact section 29 is formed by the hard component 26.

[0047] Furthermore, it is preferably provided here that the webs 28, in order to ensure that they come into contact with the contact ribs 32, have a spiral shape with respect to the geometric spindle axis 11, which is symbolized here by the angle α.

[0048] Furthermore, it is preferably provided here that a first axial relative movement of the outer tube 15 relative to the inner tube 14 resulting from a drive movement of the spindle drive 1 from the retracted position toward the extended position causes the radial displacement, in particular pivoting, of the second axial ring section 22 from the sealing position into the lift-off position. During the first axial relative movement, the axial contact section 29 comes into contact with the axial running section 31 such that the contact ribs 32 each radially deflect the second axial ring section 22 and / or the circumferential segments 25.Here, and preferably during the first axial relative movement, the deflection of the second axial ring section 22 and / or the circumferential segments 25 lifts the sealing lip 24 from the contact section 30 and, as the first axial relative movement continues, guides it along the contact ribs 32, particularly at a radial distance therefrom. Thus, when the spindle drive is extended, the friction between the sealing arrangement 20 and the respective pipe, here the inner pipe 14, is significantly reduced.

[0049] Conversely, a second axial relative movement of the outer tube 15 relative to the inner tube 14 resulting from a drive movement of the spindle drive 1 from the extended position to the retracted position causes the second axial ring section 22 to be displaced, in particular pivoted back, from the lifted position into the sealing position. During the second axial relative movement, the axial contact section 29 disengages from the axial running section 31 such that the second axial ring section 22 and / or the circumferential segments 25 can each spring back radially. Here and preferably, during the second axial relative movement, the sealing lip 24 comes back into contact with the contact section 30 from its lifted state due to the spring back of the second axial ring section 22 and / or the circumferential segments 25. This then achieves optimal sealing in the retracted position of the spindle drive.

[0050] Furthermore, it is preferably provided here that the sealing arrangement 20 is fixed to the outer tube 15 in an axially fixed and rotationally fixed manner, in particular via the first axial ring section 21, and that when the drive movements are carried out, the second axial ring section 22 can be displaced, in particular pivoted, radially outwards relative to the first axial ring section 21 from the sealing position into the lifting position. According to an alternative not shown here, it can also be provided that the sealing arrangement 20 is fixed to the inner tube 14 in an axially fixed and rotationally fixed manner, in particular via the first axial ring section 21, and that when the drive movements are carried out, the second axial ring section 22 can be displaced, in particular pivoted, radially inwards relative to the first axial ring section 21 from the sealing position into the lifting position.Here and preferably, the axially fixed and rotationally fixed fixation is provided by a material-locking connection, in particular by gluing or injection-molding, and / or an axially positive-locking connection, in particular by locking.

[0051] How Fig. 2 shows, here and preferably also an anti-twist device is provided between the inner tube 14 and the outer tube 15, which is formed here by the torsion tube 17, which is non-rotatable relative to one of the tubes, here the outer tube 15, and axially fixed relative to the spindle 4a and here to the drive motor 7, and the spindle nut tube 18, which is non-rotatable relative to the other of the tubes, in particular the inner tube 14, and axially fixed relative to the spindle nut 4b, being in positive engagement with one another. In principle, however, it is also conceivable for the inner tube 14 and the outer tube 15 themselves to be in positive engagement with one another.

Claims

1. Spindle drive for a closing element (3) of a motor vehicle, with a spindle-nut gear (4) for performing linear drive movements of the spindle drive (1) between a retracted position and an extended position, wherein a spindle-side drive portion (5) of the spindle drive (1) has a spindle (4a) of the spindle-nut gear (4), wherein a nut-side drive portion (8) of the spindle drive (1) has a spindle nut (4b) of the spindle-nut gear (4), wherein the two drive portions (5, 8) are each connected to a drive connection (9, 10) for coupling to the motor vehicle and in particular for transferring drive movements, wherein a spindle drive housing (13) with an inner tube (14) and an outer tube (15) is provided, wherein the inner tube (14) runs telescopically in the outer tube (15), wherein the outer tube (15) or the inner tube (14) has an annular sealing arrangement (20) which is circumferential to the geometric spindle axis (11) and slides along the respective other tube of the spindle drive housing (13) during performance of drive movements, characterized in that the sealing arrangement (20) has a first axial ring portion (21) and, axially adjacent thereto relative to the geometric spindle axis (11), a second axial ring portion (22) which is movably, in particular pivotably, connected to the first axial ring portion (21), and that on performance of drive movements, the second axial ring portion (22) is radially displaceable, in particular pivotable, relative to the first axial ring portion (21) between a sealing position in which a sealing effect of the sealing arrangement (20) is greatest, and a lift-off position in which the sealing effect of the sealing arrangement (20) is less than in the sealing position.

2. Spindle drive according to Claim 1, characterized in that an axial movement of the outer tube (15) relative to the inner tube (14) causes the radial displacement, in particular pivoting, of the second axial ring portion (22) between the sealing position and the lift-off position.

3. Spindle drive according to Claim 1 or 2, characterized in that the second axial ring portion (22) has an axial sealing portion (23) which presses on the respective tube of the spindle drive housing (13) with a greater radial contact force in the sealing position than in the lift-off position, preferably that the axial sealing portion (23) has a sealing lip (24) circumferential to the geometric spindle axis (11) which presses on the respective tube of the spindle drive housing (13) with a greater radial contact force in the sealing position than in the lift-off position.

4. Spindle drive according to any of the preceding claims, characterized in that for displacement, in particular pivoting, of the second axial ring portion (22) between the sealing position and the lift-off position, the second axial ring portion (22) is formed by multiple circumferential segments (25) which are arranged circumferentially next to one another and each displaceable, in particular pivotable about a geometric pivot axis tangential relative to the geometric spindle axis (11).

5. Spindle drive according to any of the preceding claims, characterized in that the first axial ring portion (21) and / or the second axial ring portion (22) and / or the circumferential segments (25) are each formed from a hard component (26) and a soft component (27), which in particular together form an integral two-component injection molding, and preferably that the sealing lip (24) is formed from the soft component (27).

6. Spindle drive according to any of the preceding claims, characterized in that the hard component (26) is made from a metal or a plastic material which has a lower modulus of elasticity and / or a higher Shore hardness than the soft component (27), in particular a glass-fiber-reinforced plastic material or polyamide, and / or that the soft component (27) is made from a permanently elastic plastic material which has a higher modulus of elasticity and / or a lower Shore hardness than the hard component (26), in particular an elastomer or liquid silicone.

7. Spindle drive according to any of the preceding claims, characterized in that the hard component (26) has several webs (28) spaced apart from one another circumferentially, preferably that the webs (28) are embedded in the soft component (27) or the soft component (27) is applied onto the webs (28), further preferably that the soft component (27) is arranged continuously circumferentially relative to the geometric spindle axis (11).

8. Spindle drive according to any of the preceding claims, characterized in that the second axial ring portion (22) and / or the circumferential segments (25) each have an axial contact portion (29) which juts out relative to the first axial ring portion (21) and / or the geometric pivot axes, radially to the tube of the spindle drive housing (13) along which the annular sealing arrangement (20) slides on performance of the drive movements, and that the tube to which the axial contact portion (29) juts out has an axial rest portion (30) for sealing contact of the sealing portion (23), and an adjacent axial running portion (31)which has axially extending contact ribs (32) protruding radially relative to the axial rest portion (32), preferably that the axial contact portion (29) is formed by the hard component (26).

9. Spindle drive according to any of the preceding claims, characterized in that the webs (28) have a swirl-like course relative to the geometric spindle axis (11).

10. Spindle drive according to any of the preceding claims, characterized in that a first axial movement of the outer tube (15) relative to the inner tube (14), resulting from a drive movement of the spindle drive (1) from the retracted position in the direction of the extended position, causes the radial displacement, in particular pivoting, of the second axial ring portion (22) from the sealing position into the lift-off position, preferably that during the first axial relative movement, the axial contact portion (29) comes into contact with the axial running portion (31) such that the contact ribs (32) deflect the second axial ring portion (22) and / or the circumferential segments (25) radially, further preferably that during the first axial relative movement, the deflection of the second axial ring portion (22) and / or the circumferential segments (25) causes the sealing lip (24) to lift off the rest portion (30), and during the further course of the first relative axial movement be guided along the contact ribs (32), in particular radially spaced therefrom.

11. Spindle drive according to any of the preceding claims, characterized in that a second axial movement of the outer tube (15) relative to the inner tube (14), resulting from a drive movement of the spindle drive (1) from the direction of the extended position into the retracted position, causes a return displacement, in particular a return pivoting, of the second axial ring portion (22) from the lift-off position into the sealing position, preferably that during the second axial relative movement, the axial contact portion (29) comes out of engagement with the axial running portion (31) such that the second axial ring portion (22) and / or the circumferential segments (25) can spring back radially, further preferably that during the second axial relative movement, the return springing of the second axial ring portion (22) and / or the circumferential segments (25) causes the sealing lip (24) to come out of its lift-off state back into contact with the rest portion (30).

12. Spindle drive according to any of the preceding claims, characterized in that the sealing arrangement (20), in particular via the first axial ring portion (21), is fastened axially and rotationally fixedly on the outer tube (15), and during performance of the drive movements, the second axial ring portion (22) is displaceable, in particular pivotable, radially outwardly relative to the first axial ring portion (21) from the sealing position into the lift-off position, or that the sealing arrangement (20), in particular via the first axial ring portion (21), is fastened axially and rotationally fixedly on the inner tube (14) and during performance of the drive movements, the second axial ring portion (22) is displaceable, in particular pivotable, radially inwardly relative to the first axial ring portion (21) from the sealing position into the lift-off position, preferably that the axially and rotationally fixed fastening takes place by a substance-bonded connection, in particular by gluing or molding, and / or an axially form-fitting connection, in particular latching.

13. Spindle drive according to any of the preceding claims, characterized in that the inner tube (14) is connected to the nut-side drive portion (8) and the outer tube (15) is connected to the spindle-side drive portion (5).

14. Spindle drive according to any of the preceding claims, characterized in that a twist lock is provided between the inner tube (14) and outer tube (15), preferably that the twist lock is formed in that a torsion tube (17), which is rotationally fixed relative to the one of the tubes, in particular the outer tube (15), and axially fixed relative to the spindle (4a), and a spindle nut tube (18) which is rotationally fixed relative to the other of the tubes, in particular the inner tube (14), and axially fixed relative to the spindle nut (4b), stand in form-fit engagement with one another, or that the inner tube (14) and the outer tube (15) themselves stand in form-fit engagement with one another.

15. Spindle drive according to any of the preceding claims, characterized in that the spindle-side drive portion (5) has a drive unit (6) with a drive motor (7), downstream of which the spindle (4a) is connected, and the drive unit (6) and spindle-nut gear (4) are arranged one behind the other along the geometric spindle axis (11), and / or that at least one coil spring (16) is arranged inside the inner tube (14) coaxially to the geometric spindle axis (11) and preloads the two drive portions (5, 8) against one another, preferably that a spring guide tube runs inside the at least one coil spring (16) and at one of its ends is fixed to the spindle-side drive portion (5), further preferably that the spring guide tube is formed by the torsion tube (17).

16. Spindle drive according to any of the preceding claims, characterized in that the spindle drive housing (13) radially surrounds the spindle-nut gear (4), the drive motor (7), the torsion tube (17), the spindle nut tube (18) and / or the at least one coil spring (16), in particular over their entire axial extent.