Spindle drive

Abstract

The present invention relates to a spindle drive (10) comprising a housing (12), a motor assembly (14) with a rotatably driven motor shaft (16) which defines a longitudinal direction (L14) of the motor assembly (14), wherein a bevel gear (18) is associated with the motor shaft (16), an intermediate gear (24) rotatably mounted relative to and received in the housing (12) with a longitudinal direction (L24), which has at a first end a first bevel gear section (24a) which forms a first bevel gear transmission (26a) with the bevel gear (18) of the motor shaft (16), and at a second end opposite the first end has a second bevel gear section (24b), wherein the longitudinal direction (L14) of the motor assembly (14) and the longitudinal direction (L24) of the intermediate gear (24) are oriented substantially perpendicular to each other, a spindle (32) with a spindle nut mounted thereon and engaged therein (30)wherein the spindle (32) extends along a spindle axis (L32), wherein the spindle (32) and the spindle nut (30) are pivotably mounted together about a pivot axis (L24) in the housing (12), which extends substantially along the longitudinal direction (L24) of the intermediate gear (24), and wherein the spindle nut (30) is furthermore rotatably mounted about the spindle axis (L32) in the housing (12) and is provided with a spindle nut bevel gear section (30a) which, together with the second bevel gear section (24b) of the intermediate gear (24), forms a second bevel gear drive (26b), such that the spindle nut (30) can be driven into rotation by the motor assembly (14) via the intermediate gear (24) in order to extend and retract the spindle (32).

Description

[0001] The present invention relates to a spindle drive with a housing, a motor assembly and a spindle that can be displaced relative to the motor assembly, as well as a door or flap arrangement for a vehicle which includes such a spindle drive.

[0002] If a spindle drive is to trigger a relative displacement of two pivotably connected higher-level assemblies, then, in order to compensate for the pivoting and the associated traverse of a relative path curve between the two connection points of the spindle drive on the respective higher-level assemblies, at least the spindle must be pivotable relative to the other higher-level assembly during extension and retraction.

[0003] Various approaches have been pursued in the prior art to achieve this. For example, in known devices from the prior art, such a pivoting movement was implemented via a joint located between the drive and the corresponding connection to the associated higher-level assembly, for instance, by means of a pivotable pair of angle brackets. However, as a consequence of this, the entire drive pivots relative to the corresponding higher-level assembly, resulting in disadvantages regarding the required installation space. Furthermore, in the known prior art, the longitudinal direction of the corresponding motor assembly is oriented perpendicular to the spindle axis, which, depending on the installation position, can also lead to disadvantages regarding the required installation space of the overall arrangement.

[0004] Furthermore, certain designs of previously used spindle drives show that the worm drives used between the motor assembly and the spindle or spindle nut also require more installation space due to the necessary axial offset between the worm wheel and the worm, whereas the available installation space in this direction is usually very limited.

[0005] Alternatively, the approach of enabling the necessary pivoting movement discussed above solely through the spindle within the drive was pursued; however, in corresponding spindle drives, depending on the available installation space, the alternative alignment of the motor assembly parallel to the hinge axis is disadvantageous for the reasons just mentioned. Furthermore, the axis offset, which increases the installation space, also occurs in a similar manner with such spindle drive designs.

[0006] Therefore, the object of the present invention is to eliminate the disadvantages of the prior art discussed above and to provide a spindle drive in which, on the one hand, a kinematically necessary pivoting movement of the spindle axis is separated from the motor assembly and thus from the drive itself, and on the other hand, the longitudinal direction of the motor assembly is oriented in a space-saving manner.

[0007] To solve this problem and to overcome the disadvantages of the prior art discussed above, a spindle drive is proposed according to the invention, comprising a housing, a motor assembly with a rotatably driven motor shaft which defines a longitudinal direction of the motor assembly, wherein a bevel gear is associated with the motor shaft, an intermediate gear rotatably mounted relative to and received in the housing with a longitudinal direction, which has a first bevel gear section at a first end which forms a first bevel gear transmission with the bevel gear of the motor shaft, and a second bevel gear section at a second end opposite the first end, wherein the longitudinal direction of the motor assembly and the longitudinal direction of the intermediate gear are oriented essentially perpendicular to each other, a spindle extending through the housing with a spindle nut mounted on it and engaged therein,wherein the spindle extends along a spindle axis, wherein the spindle and the spindle nut are jointly pivotably mounted in the housing about a pivot axis which extends substantially along the longitudinal direction of the intermediate gear, so that pivoting of the spindle in a predetermined pivot range is possible in a plane which is substantially parallel to the longitudinal direction of the motor assembly, and wherein the spindle nut is furthermore rotatably mounted in the housing about the spindle axis and is provided with a spindle nut bevel gear section which forms a second bevel gear drive with the second bevel gear section of the intermediate gear, so that the spindle nut can be driven in rotation by the motor assembly via the intermediate gear in order to extend and retract the spindle.

[0008] Accordingly, the invention makes it possible to align the longitudinal direction of the motor assembly and the pivotable bearing of the spindle and the spindle nut essentially parallel to each other by providing the intermediate gear and the overall pivotable bearing of the spindle, which enables improved integration of such a spindle drive with regard to the often limited installation space in many applications, while at the same time separating a kinematically necessary pivoting movement of the spindle axis from the motor assembly without the need for additional external components, such as an external joint between the motor assembly and the higher-level assembly on which the spindle drive would be mounted.Furthermore, the provision of the two bevel gear drives avoids a widening of the spindle drive in relation to the pivot plane of the spindle, which will also have an advantageous effect on the required installation space of the spindle drive.

[0009] In this case, in a central position of the spindle's swivel range, the spindle axis can be essentially aligned parallel to the longitudinal direction of the motor assembly, whereby, in principle, other angular relationships between the spindle axis and the longitudinal direction of the motor assembly would also be conceivable through the design of the spindle drive with two offset bevel gear drives.

[0010] One embodiment for enabling the rotatable mounting of the spindle nut and the spindle consists of providing a bearing cage which in turn carries at least one bearing unit for the rotatable mounting of the spindle nut and is designed to guide the pivoting of the spindle and the spindle nut about the pivot axis. In such an embodiment, this bearing cage is received within the housing and supported or mounted thereon in a suitable manner.

[0011] The housing in question can also be closed on opposite sides, relative to the longitudinal direction of the intermediate gear, by respective first and second housing covers, whereby during the assembly of the spindle drive access to the interior of the housing can first be created, and after completion of the installation of the components inside the housing, it can be hermetically sealed to prevent the ingress of foreign substances.

[0012] Furthermore, the spindle drive according to the invention can comprise an elastic element, and in particular a spring, which is configured to preload an axial bearing supporting the motor shaft in the axial and radial directions, and the motor shaft itself. In such an embodiment, the housing can also be filled with a potting compound in the area of ​​a cavity on the side facing away from the motor shaft in order to compensate for possible length tolerances of the motor shaft.

[0013] Furthermore, to prevent the ingress of foreign substances into the spindle area, it can be surrounded by a bellows on at least one side protruding from the housing. The spindle can also be assigned a first connection element for linking to a first higher-level assembly, and the housing a second connection element for linking to a second higher-level assembly.

[0014] As already indicated above, according to a further aspect, the present invention relates to a door or flap arrangement for a vehicle, comprising a vehicle door or flap pivotally mounted on a vehicle body of the vehicle about a hinge axis and a spindle drive of the type described above according to the invention arranged between the vehicle body and the vehicle door or flap, as well as also a vehicle which comprises at least one such door or flap arrangement.

[0015] Further features and advantages of the present invention will become even clearer from the following description of an embodiment thereof, when viewed together with the accompanying figures. These show in detail: Fig. 1 an isometric view of a spindle drive according to the invention; Fig. 2 a side sectional view of the spindle drive Fig. 1 and an enlarged view of a section of it; and Fig. 3 three sectional top views of the spindle drive from the Fig. 1 and Fig. 2 in three different swivel states.

[0016] In the Fig. Figures 1 to 3 each depict a spindle drive according to the invention in different views and are generally designated by reference numeral 10. The spindle drive 10 comprises a central housing 12 and a motor assembly 14, which are rigidly connected to one another. The motor assembly 14, in turn, comprises an electric motor (not shown here) in a manner known per se, which is configured to drive the spindles shown in the sectional view. Fig. The motor shaft 16, as shown in the diagram, is driven into rotation. It should be noted that the motor assembly 14 may also include a gearbox (not shown) located between the electric motor and the motor shaft 16. Furthermore, the direction of extension of the motor shaft 16 defines a longitudinal direction L14 of the motor assembly 14, and a bevel gear 18 is associated with the motor shaft 16, which is also set into rotation when the motor assembly 14 is operated.

[0017] At this point, particular attention should be drawn to the enlarged view of a section of it in Fig. Figure 2 on the right, in which this bevel gear 18 can be seen particularly well. At this point, reference should also be made to the spring 20, which is designed to preload the axial and radial thrust bearings 22 supporting the motor shaft 16 in the direction of the motor shaft 16, and the cavity in the housing 12 on the side facing away from the motor shaft 16 is further filled with a potting compound M to compensate for possible length tolerances of the motor shaft 16.

[0018] The bevel gear 18 of the motor shaft 16 meshes with a first bevel gear section 24a of an intermediate gear 24, which is housed in the casing 12, to form a first bevel gear drive 26a. The intermediate gear 24 is rotatably mounted relative to the casing 12 by a ball bearing 28 and, on its side opposite the first bevel gear section 24a, comprises a second bevel gear section 24b, which in turn meshes with a spindle nut bevel gear section 30a of a spindle nut 30 to form a second bevel gear drive 26b. In this way, the rotation of the motor shaft 16, initiated by the motor assembly 14, is converted into a rotation of the spindle nut 30, which in turn is mounted on a spindle 32 and drives the spindle to retract and extend relative to a spindle axis L32, i.e., to perform a lifting motion.By selecting the dimensions of the individual bevel gears 18, 24a, 24b and 30a, a gear ratio can be set which determines a translation between the speed of the motor assembly 14 and the stroke speed of the spindle 32.

[0019] Here, the spindle nut 30 is also rotatably mounted by means of ball bearings 34 in a bearing cage 36, which furthermore allows the spindle 32 and the spindle nut 30 to pivot together about a pivot axis L24 extending along the longitudinal direction of the intermediate gear 24. By providing the second bevel gear 26b, it is possible to drive it via the intermediate gear 24 independently of the pivot position of the spindle nut 30, whereby the Fig. Figure 3 in sectional view illustrates three corresponding swivel positions of the spindle 32 relative to the motor assembly 14.

[0020] It should also be noted that the spindle 32 is provided on both sides exiting the housing 12 with respective bellows 38, which, like the first and second housing covers 12a and 12b provided on both opposite sides of the housing 12, prevent the ingress of foreign substances into the housing 12 of the spindle drive 10. Furthermore, it should be noted that the spindle 32 is connected to the Fig. 2 and Fig. 3 each at the right end carries a first connection element 40 for connection to a first superior assembly, while the housing 12 is assigned a further connection element 42 for connection to a second superior assembly.

[0021] If the first and second higher-level assemblies (not shown here) are pivotally connected to each other, then, when such a pivoting motion of the first and second higher-level assemblies is driven, corresponding to a pivoting of the first and second application elements 40 and 42 relative to each other, a pivoting of the spindle 32, which performs a corresponding lifting movement, is also necessary relative to the housing 12 and thus to the motor assembly 14. Therefore, each of the in Fig. The 3 pivot positions shown in the illustrations indicate a connection of the spindle drive 10 with the two mentioned superior assemblies, and the spindle drive 10 according to the invention makes it possible to actuate such pivotably connected superior assemblies, such as a vehicle body and a vehicle door or a vehicle flap.

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