Patent Application
20220136310
The present disclosure relates to a spindle drive for motor-driven adjustment of an adjustable element for use in a motor vehicle.
A spindle drive may be used for all possible adjustable elements of a motor vehicle. Examples thereof include a tailgate, a trunk lid, a door, such as a side door, an engine hood or the like, of a motor vehicle.
According to one or more embodiments, the spindle drive may include a braking arrangement configured to brake a rotational movement of the drive-side mechanism component of the spindle-spindle nut mechanism, such as of the spindle, in such a way that a part of the braking arrangement, such as an axial section of the braking arrangement, is integrated into the speed reduction gear, such as, into a planetary gear of the speed reduction gear. The braking arrangement is thus not a unit which is separate from the speed reduction gear and may include frictional engagement elements that are separate and spaced apart axially from the speed reduction gear and may be in frictional engagement in order to produce the braking action. On the contrary, at least one of the frictional engagement elements of the braking arrangement may be provided on a planet carrier. At least one other frictional engagement element, which is in frictional engagement therewith, is provided on the housing side, that is to say is rotationally fixed with respect to the drive housing.
In the case where only one planetary gear and correspondingly only one planet carrier is provided, the planet carrier with the respective at least one frictional engagement element is that planet carrier which is coupled to the spindle-spindle nut mechanism.
According to the proposal, however, it is also possible for the planetary gear assembly to have a plurality of, such as two, planetary gears, in which case one of the two planet carriers, such as the planet carrier on the feed mechanism side, that may be at the rear in terms of drive, is the one with the at least one frictional engagement element. In principle, it is also possible to provide more than one planet carrier with at least one corresponding frictional engagement element, which, as part of the braking arrangement, is in frictional engagement with at least one frictional engagement element on the housing side. With the braking arrangement provided according to the proposal, at least one planetary gear of the speed reduction gear, possibly also a plurality of planetary gears, is or are braked directly, as a result of which, ultimately, the rotational movement of the drive-side mechanism component of the spindle-spindle nut mechanism, in particular the spindle, is braked. Since, in the solution according to the invention, the braking arrangement does not form a unit separate from the speed reduction gear or from the feed mechanism, but is at least partially integrated into the speed reduction gear, the technical length of the spindle drive and thus correspondingly also the installation space in the motor vehicle can be significantly reduced.
More specifically, it is now proposed that the braking arrangement may include at least one first frictional engagement element, which is fixed in terms of rotation relative to the drive housing, and at least one second frictional engagement element, which is in frictional engagement with the respective first frictional engagement element and is connected to the planet carrier or one of the planet carriers for conjoint rotation therewith. In this case, the braking arrangement brakes at least one planet carrier and a plurality or all of the planet carriers of the planetary gear assembly, more specifically directly, i.e. by direct frictional contact between at least one frictional engagement element on the planet carrier side and at least one frictional engagement element on the housing side. In this case, the braking action is particularly preferably a continuous braking action.
The frictional engagement elements may be in frictional engagement with one another in the axial direction, with the result that the planet carrier, in particular the planet carrier which transmits the torque to the drive-side mechanism component of the spindle-spindle nut mechanism, is braked axially (claim 2). In addition or as an alternative, however, it is also possible to provide radially frictional engagement (claim 3).
According to one or more embodiments, the planetary gear assembly may include exactly one planetary gear. In this case, the only planet carrier is the one which transmits the torque to the drive-side mechanism component. This planet carrier is at the same time that planet carrier which may include the at least one frictional engagement element interacting frictionally with the at least one housing-side frictional engagement element. Alternatively, the planetary gear assembly can also have a plurality of planetary gears and, correspondingly, a plurality of planet carriers, wherein one of the planetary gears is connected downstream of the other of the planetary gears in terms of drive. The planetary gear which is connected downstream in terms of drive is then that planetary gear which or the planet carrier of which is coupled to the spindle-spindle nut mechanism.
As an example, the drive connection of two planetary gears of the planetary gear assembly may be connected in series.
According to one or more embodiments, at least one third frictional engagement element may be provided on the planet carrier of the planetary gear at the front in terms of drive in the planetary gear assembly that may include a plurality of planetary gears. This at least one third frictional engagement element is likewise part of the braking arrangement.
As an example, a contact pressure force of the frictional engagement elements may move the frictional engagement elements toward one another. The contact pressure mechanism may be adjustable. The contact pressure mechanism may include a spring arrangement, such as at least one helical spring.
According to another embodiments, an adjustable element assembly of a motor vehicle having an adjustable element and a spindle drive as above according to the proposal is provided. To this extent, reference may be made to all statements regarding the spindle drive according to the proposal.
The invention is explained in greater detail below with reference to a drawing, which illustrates only illustrative embodiments. In the drawing:
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
A known spindle drive is disclosed in DE 20 2017 102 066 U1, is equipped with a rotary drive motor, a speed reduction gear connected downstream of the drive motor, and a feed mechanism connected downstream of the speed reduction gear. The speed reduction gear of the known spindle drive is designed as a planetary gear assembly with a planetary gear which, as the usual planetary gear components, has a sun wheel, an annulus and a planet carrier with planets. In order to produce linear drive movements in an axial direction, the feed mechanism is designed as a spindle-spindle nut mechanism which has a spindle on the drive side and a spindle nut on the output side as the usual mechanism components.
The known spindle drive may be advantageous since it permits reliable holding of the adjustable element in the open position or in intermediate positions. For this purpose, a braking arrangement which brakes the rotational movement of the drive spindle is provided in the drive train of the spindle drive. In this case, the braking arrangement is designed as a separate unit which has frictional engagement elements that are in frictional engagement with one another and provide the braking action by means of the frictional engagement produced. In this case, the unit comprising the braking arrangement is connected in terms of drive between the planetary gear of the planetary gear assembly and the spindle-spindle nut mechanism. In this case, the planetary gear has an output element on the output side, which interacts with a drive element of the braking arrangement in terms of drive, that is to say in a torque-transmitting manner. In turn, the braking arrangement itself has an output-side output element, which interacts with a drive element of the spindle-spindle nut mechanism, in this case the spindle. All the aforementioned drive components of the spindle drive, namely the drive, speed reduction gear, braking arrangement and feed mechanism, are accommodated one behind the other in an elongate, telescopic drive housing and are aligned with a common drive axis, the direction of extent of which is referred to below as the axial direction. The drive housing has a correspondingly large technical length and accordingly takes up a relatively large amount of installation space in the motor vehicle.
The problem underlying the invention is that of configuring and developing the known spindle drive in such a way that its technical length and thus the installation space required in the motor vehicle are reduced.
The spindle drive illustrated in the drawing serves for the motor-driven adjustment of an adjustable element 1 of a motor vehicle designed as a tailgate. This is to be understood to be advantageous, but not restrictive. On the contrary, the spindle drive according to the proposal can be used for all possible adjustable elements of a motor vehicle, as will be explained further below.
The spindle drive is equipped with a drive motor 2, a speed reduction gear 3 connected downstream of the drive motor 2, and a feed mechanism 4, connected downstream of the speed reduction gear, for generating linear drive movements. The speed reduction gear 3 is designed as a planetary gear assembly with at least one planetary gear 3a, 3b. According to
The respective planetary gear 3a, 3b may include a sun wheel 5, a planet carrier 6 with planets 6a, and an annulus 7 as planetary gear components. The sun wheel 5 is rotatable about a corresponding sun wheel axis. Coaxially therewith, the planet carrier 6 is rotatable about a planet carrier axis, wherein the planets 6a are each rotatable on the planet carrier 6 about their own planet axes. The annulus 7 is also rotatable coaxially with the sun wheel 5 on an annulus axis, wherein the annulus 7 may be fixed with respect to the housing, that is to say permanently fixed rotationally and axially. It is also conceivable that the annulus 7 is lockable, enabling it to be locked or to be freely rotatable about its annulus axis, depending on the state. In the latter case, the respective planetary gear 3a, 3b can be used as a shiftable clutch. The planets 6a are in axially parallel engagement with the sun wheel 5, on the one hand, and with the annulus 7, on the other hand. Here, the term “axially parallel” means that the sun wheel axis, the planet axes and the annulus axis are aligned parallel to one another.
The feed mechanism 4, which is designed as a spindle-spindle nut mechanism, has a drive-side mechanism component and an output-side mechanism component in meshing engagement therewith (
As an example, the torque generated by the drive motor 2 is permanently transmitted to the spindle 8 via the planet carrier 6 coupled to the feed mechanism 4. “Coupled” means that the two respective elements, in this case planet carrier 6 and spindle 8, are in engagement with one another in terms of drive, that is to say in a torque-transmitting manner. Alternatively, it is also possible to conceive of an embodiment in which the torque generated by the drive motor 2 is transmitted to the spindle 8 either via the annulus 7 or via the planet carrier 6, depending on the gear position of the respective planetary gear 3a, 3b.
Furthermore, a braking arrangement 10 is provided which brakes the rotary motion of the spindle 8 and permits reliable holding of the adjustable element 1, for example a tailgate, in intermediate positions.
A particularly slim design may result from the fact that the drive motor 2, the speed reduction gear 3 and the feed mechanism 4 are accommodated one behind the other in a substantially elongate drive housing 11 and are aligned with a common drive axis 12.
As an example, it is possible with the respective planetary gear 3a, 3b to form a non-self-locking configuration of the speed reduction gear 3. For this purpose, the respective planetary gear 3a, 3b can be configured as a gear with helical teeth, for example. The planetary gear 3a, 3b can, for example, also be configured as an evoloid gear, the sun wheel 5 of which has only a single pinion tooth, which has an involute profile running in a spiral around the sun wheel axis. The planets 6a and the annulus 7 then have corresponding teeth. Reference may be made to DE 20 2011 106 149 U1 for the technical details of such evoloid toothing. It may be provided that the speed reduction gear 3, or even the entire drive train that may include the drive motor 2, speed reduction gear 3 and feed mechanism 4, is of a non-self-locking configuration. This is may be advantageous when the spindle drive is used as a tailgate drive, making manual adjustment of the tailgate 1 readily possible when the drive motor 2 is not being supplied with power.
In the spindle drive according to the proposal, as already indicated above, a torque is now transmitted from the single planetary gear 3a (
The crucial point is now that the braking arrangement 10 has at least one first frictional engagement element 15a, 15b, which is fixed in terms of rotation relative to the drive housing 11, and at least one second frictional engagement element 16a, 16b, which is in frictional engagement with the respective first frictional engagement element 15a, 15b and is connected to the planet carrier or one of the planet carriers 6 for conjoint rotation therewith. As an example, the braking arrangement 10 is designed for continuous braking of the respective planet carrier 6. An additional braking arrangement 10 to the one described here and may not be provided in the drive train of the spindle drive. The braking arrangement 10 is thus preferably the only braking arrangement of the spindle drive.
In the following, the exemplary embodiment according to
As an example, the planet carrier 6, which here is the only planet carrier 6 of the planetary gear assembly, is provided on its two axial sides with a respective second frictional engagement element 16a, 16b, namely on the axial side facing the feed mechanism 4 with frictional engagement element 16a and on the axial side facing the drive motor 2 with frictional engagement element 16b. Each of the second frictional engagement elements 16a, 16b interacts frictionally with an associated first frictional engagement element 15a, 15b, each of which is fixed in terms of rotation relative to the drive housing 11. Here, frictional engagement element 16a of the planet carrier 6 interacts, in each case frictionally, with a frictional engagement element 15a on the housing side, and the other frictional engagement element 16b of the planet carrier 6 interacts with the other frictional engagement element 15b on the housing side. In one or more embodiments, the respective frictional resistance between frictional engagement elements 15a and 16a, on the one hand, and between frictional engagement elements 15b and 16b, on the other hand, is equal. In principle, however, it is also conceivable to provide frictional resistances of different magnitudes between the individual pairs of frictional engagement elements. Thus, it is conceivable to provide balls, rollers or the like in the case of one pair of frictional engagement elements, for example between frictional engagement elements 15b and 16b, thus ensuring that only rolling friction occurs here, whereas in the case of the other pair of frictional engagement elements static friction occurs when the spindle drive is stationary and sliding friction occurs during operation of the spindle drive. The rolling friction then causes, in particular, lower frictional resistance than the static or sliding friction.
In one or more embodiments, exactly one frictional engagement element 16a, 16b is provided on the planet carrier 6 on each axial side. In principle, however, it is also possible to provide more than one frictional engagement element 16a, 16b on one or the other axial side or on both axial sides of the planet carrier 6. The same applies to the frictional engagement elements 15a, 15b on the housing side, of which, here too, in each case only one is provided on the relevant axial side. In principle, however, it is also possible to provide more than one housing-side frictional engagement element 15a, 15b on one or the other axial side or on both axial sides of the planet carrier 6.
In principle, as illustrated in
Alternatively, though not illustrated here, provision can also be made, however, for the first frictional engagement element 15a, 15b or at least one of the first frictional engagement elements 15a, 15b and the second frictional engagement element 16a, 16b or at least one of the second frictional engagement elements 16a, 16b to be in frictional engagement with one another radially. Thus, it is also conceivable here for the one first frictional engagement element 15a and the one second frictional engagement element 16a and/or the other first frictional engagement element 15b and the other second frictional engagement element 16b each to be in frictional engagement with one another radially. Frictional engagement elements 15a, 16a, on the one hand, and frictional engagement elements 15b, 16b, on the other hand, can be in frictional engagement with one another radially on the inside and/or radially on the outside of the planet carrier 6.
In this case, one planetary gear 3a is coupled to the drive side of the spindle drive, namely to the drive motor 2, whereas the other planetary gear 3b is coupled to the spindle-spindle nut mechanism. As an example, the planetary gear 3a coupled to the drive side is connected upstream of the planetary gear 3b coupled to the spindle-spindle nut mechanism. Correspondingly, the planet carrier 6 transmitting the torque to the drive-side mechanism component, here the spindle 8, is the planet carrier 6 of the planetary gear 3b at the rear in terms of drive. In this case, the sun wheel 5 of this planetary gear 3b at the rear in terms of drive is coupled to the planet carrier 6 of the planetary gear 3a which is connected upstream or at the front in terms of drive. In this case, the sun wheel 5 of planetary gear 3b and the planet carrier 6 of planetary gear 3a are arranged on a common shaft for conjoint rotation therewith.
It should be noted that, in the exemplary embodiment according to
In the case described, in which the planetary gear assembly has a plurality of, in particular two, planetary gears 3a, 3b, the braking arrangement 10 preferably has at least one third frictional engagement element 19a, 19b, which is connected for conjoint rotation to the planet carrier 6 of that planetary gear 3a which, in terms of drive, is connected upstream of the planetary gear 3b coupled to the spindle-spindle nut mechanism. In this case, the at least one third frictional engagement element 19a, 19b is in each case in frictional engagement with at least one of the further frictional engagement elements 15a, 15b, 16a, 16b.
In the exemplary embodiment in
In a case with a planetary gear assembly which has a plurality of, in particular two, planetary gears 3a, 3b, as is illustrated by way of example in
Additionally or alternatively, the first frictional engagement element 15a, 15b or the second frictional engagement element 16a, 16b, each of which interacts frictionally with a third frictional engagement element 19a, 19b, may also be in frictional engagement radially with the third frictional engagement element 19a, 19b. Accordingly, it can be provided that the third frictional engagement element 19a or at least one of the third frictional engagement elements 19a, 19b and at least one of the second frictional engagement elements 16a, 16b are in frictional engagement with one another radially. Additionally or alternatively, it can also be provided that the third frictional engagement element 19b or at least one of the third frictional engagement elements 19a, 19b and at least one of the first frictional engagement elements 15a, 15b are in frictional engagement with one another radially.
As an example, the braking arrangement 10 has a contact pressure mechanism 17 for generating a contact pressure force, here an axial contact pressure force, of the frictional engagement elements toward one another. In the case of radial frictional engagement, as described above, between in each case two frictional engagement elements, it is also possible to provide a contact pressure mechanism which generates a corresponding radial contact pressure force of the frictional engagement elements toward one another. The contact pressure force of the frictional engagement elements is preferably adjustable.
In one or more embodiments, the contact pressure mechanism 17 may include a spring arrangement 18, the spring preload of which defines the contact pressure force. The spring preload and thus the contact pressure force may be adjustable. As an example, the spring arrangement 18 may include at least one helical spring, in particular a helical compression spring.
Achieving adjustability of the contact pressure force by means of a spring arrangement 18, the spring preload of which is adjustable, is not the only conceivable possibility. Additionally or alternatively, it is also conceivable for the contact pressure force to be adjustable via the adjustment of gear components with helical teeth or evoloid teeth in the respective planetary gear 3a, 3b.
As an example, it is further provided that the output element 13, which is connected for conjoint rotation to the planet carrier 6 which transmits the torque to the drive-side mechanism component, in particular the spindle 8, is arranged radially inside an axial section 10a of the braking arrangement 10 and/or radially inside an axial section 17a of the contact pressure mechanism 17. Additionally or alternatively, the drive element 14, which is provided for transmitting a drive-side torque to the planet carrier 6 of the respective drive-side planetary gear 3a, 3b and is connected to the sun wheel 5 for conjoint rotation therewith, can also be arranged radially inside an or the axial section 10a of the braking arrangement 10 and/or radially inside an or the axial section 17a of the contact pressure mechanism 17. In each case, this has the advantage that the technical length of the spindle drive can be further reduced.
Finally, the mode of operation of the feed mechanism 4 may be discussed in more detail. Operation of the drive motor 2 causes a speed-reduced rotation of the output element 13 of the speed reduction gear 3, which is transmitted to the spindle 8. Rotation of the spindle 8 causes a linear adjustment of the spindle nut 9 and thus a linear adjustment of a guide tube 20, which is fixedly connected to the spindle nut 9. The guide tube 20 is in turn connected in the region of a connection 21 of the spindle drive to a housing outer tube 11a of the drive housing 11, which can be telescoped with respect to a housing inner tube 11b of the drive housing 11. The housing inner tube 11b is, in turn, connected to an opposing connection 22. It furthermore accommodates the preferably preassembled unit comprising the drive motor 2, speed reduction gear 3 and braking arrangement 10. If appropriate, a clutch, not illustrated here, can also be provided in the drive train, and can likewise be a component of the preassembled unit. As an example, the spindle drive can be assembled as a variable modular system, depending on customer requirements.
According to another embodiment, an adjustable element assembly of a motor vehicle having an adjustable element 1 and a spindle drive above according to the proposal for motor-driven adjustment of the adjustable element 1 is provided. Reference may be made to all statements regarding the spindle drive according to the proposal which are suitable for explaining the adjustable element assembly.
As explained above, numerous variants are conceivable for the adjustable element 1. In a particularly preferred configuration, the adjustable element 1 is a tailgate, a trunk lid, a door, in particular a side door, an engine hood or the like, of a motor vehicle.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
The following is a list of reference numbers shown in the Figures. However, it should be understood that the use of these terms is for illustrative purposes only with respect to one embodiment. And, use of reference numbers correlating a certain term that is both illustrated in the Figures and present in the claims is not intended to limit the claims to only cover the illustrated embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 103 682.8 | Feb 2019 | DE | national |
This application is the U.S. National Phase of PCT Application No. PCT/EP2020/053695 filed on Feb. 13, 2020, which claims priority to German Patent Application No. DE 10 2019 103 682.8, filed on Feb. 13, 2019, the disclosures of which are hereby incorporated in their entirety by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/053695 | 2/13/2020 | WO | 00 |
