Patent Application
20080244980
The present patent application claims priority from German Utility Model application no. DE 20 2007 005 143 filed on 4 Apr. 2007, the whole contents of which are hereby explicitly incorporated into the present application by reference.
The invention relates to a drive assembly for a cable window lift system of motor vehicles having a drive unit that has a gear housing section. Furthermore, the invention relates to a cable window lift system that is fitted with such a drive assembly. The invention refers to the earlier and already published application US 2005/0067521 A1, the whole contents of which are hereby explicitly incorporated in the present application by reference.
In the known drive assemblies and units for cable window lift systems for motor vehicles, a cable drum is usually provided which is mounted on a shaft in the gear housing section of the drive unit and which is driven by a drive gear that is frequently designed as a worm wheel. At least one cable for raising and lowering of the window pane is moved by way of the cable drum.
Such a drive assembly is known for example from DE 103 42 074 A1 and the corresponding US 2005/0067521 A1. In the gear unit described therein a shaft is provided in the shape of a pivot pin on which the cable drum is rotatably mounted and by way of which a worm wheel is driven. The shaft or the pivot pin is designed as part of the gearbox or gear housing and penetrates a cylindrical through opening provided in the cable drum. Depending on the field of use, the shaft may, for example, be designed as a steel axle or bolt integrally moulded to the housing, as an integral plastic shaft or even as a back-moulded metal sleeve. The shaft projecting through the cable drum may bring about especially secure mounting of the cable drum. However, if anything it is difficult with regard to the choice of material and dimensioning to make this design principle easily adaptable to many different application cases. This is because generally speaking plastic shafts are only suitable for small forces and conceal the inherent risk of a failure even during development or trial operation. The changeover to steel shafts or similar elements which may become necessary at a later stage is then rather expensive and critical in terms of time. Even the length of the shaft itself is a design parameter which has a not insignificant effect on the overall design, particularly with regard to dimensioning, which in turn restricts the scope of possible variations for different application cases and areas of use of cable window lift systems.
EP 0 360 911 B1 discloses an electric drive unit for motor vehicle cable window lift systems. In the base of the gear housing section made of plastic is embedded a steel shaft which serves to radially secure both the drive's worm wheel and also the cable drum coupled to it and which projects with a predetermined length away from the gear housing section. The cable drum is coupled to the worm wheel by way of a disc-like damping element and is pushed onto the steel bolt. The cable drum is mounted in a cup-shaped bearing cover which is fixedly connected to the drive unit. At the same time the steel bolt extends through a central hole in the bearing cover. On the front face of the cable drum directed towards the bearing cover is provided a central securing clip which is clipped into the central hole of the bearing cover so as to additionally mount the cable drum on said cover. The axial pressure thus applied to the cable drum secures it axially in the cable drum receptacle. The cable drum is radially mounted on the steel bolt. The cable drum is not secured axially directly on the worm wheel but rather by the medium of the damping disc. Overall this construction is comparatively complex as it requires a relatively large number of individual components. Due to the design of the bearing cover, the drive assembly is only suitable for mounting one type of cable drum with a predetermined height which is prescribed by the height of the cup-shaped recess in the bearing cover.
The object of the invention is to propose a drive assembly for cable window lift systems which offers variable design possibilities in a simple and advantageous manner and thus can cover an extended range of application areas. Furthermore, a cable window lift system equipped therewith is also proposed here.
The object is achieved by a drive assembly with the features of claim 1 in addition to a cable window lift system with the features of claim 20. Further advantageous embodiments are the subject of related subclaims.
According to this, a drive assembly for a cable window lift system of motor vehicles is proposed comprising:
The meaning of “in a shaftless manner” is to be understood to comprise all ways of mounting without using any shaft, i.e. any shaftless or shaft-free mounting of the cable drum in accordance with the present invention, e.g. as a skilled person can derive from the enclosed figures.
The drive assembly presented here is thus provided with a cable drum which engages with a drive gear, which may, for example, be a worm wheel, but is mounted shaftlessly or shaft-free wherein at least one securing means is provided that secures the cable drum axially and radially on the drive gear. As a result of this secured and rotatably mounted structural design it is possible to dispense with a shaft penetrating the cable drum or a longer pivot pin. The result is a shaftless or shaft-free structural design which may be designed very flexibly by comparison with conventional structural designs. In particular, due to the shaft-free mounting proposed here, it is possible to use a variety of different cable drums in order to co-operate with the drive unit which results in a very large range of possible variations when using the same drive unit. The structural design presented here and also its adaptation may be realised with comparative ease as a result of which the production price, amongst other things, is considerably reduced.
Especially advantageous developments of the invention emerge from the subclaims:
Accordingly, it is advantageous if the cable drum has, on a side directed away from the drive gear, a rotationally symmetrical recess or protrusion which co-operates with a correspondingly shaped protrusion or recess that is secured axially in relation to the gear housing section by way of which the cable drum can be secured axially and radially on the drive gear in a shaft-free manner. Preferably the recess is designed to be cup-shaped and the correspondingly shaped protrusion to be cylindrical. In the process, the cup-shaped protrusion may be formed or provided on a housing cover of the drive unit which is detachably joined to said drive unit. In addition it may be provided that the housing cover seals the gear housing section. As a result an efficient overall structural design of the drive unit emerges which achieves both accommodation of the drive unit itself as well as secured mounting of the cable drum in an advantageous manner.
According to a further embodiment, the cup-shaped protrusion may be formed or provided on a web or bar detachably joined to the drive unit, said web or bar diametrically bridging over or encroaching on a bearing section of the drive unit which holds the drive gear. The cup-shaped protrusion may also preferably be provided or formed on a carrier plate on which further components of a vehicle door, for example operating elements, side airbag module, window lift rail, are mounted or may be mounted. The carrier plate including the cup-shaped protrusion may at the same time be formed from a metal sheet, for example using the punching/stamping technique, or from a plastic, in particular by injection moulding.
According to a further embodiment, the rotationally symmetrical recess may be formed in the cable drum wherein a securing element, secured axially in relation to the drive unit and shaped correspondingly to said recess engages in the recess in order to secure the cable drum axially and radially on the drive gear. In the process, the securing element may be provided or formed on a housing cover or a carrier plate which is joined to the drive unit. In particular, the securing element may be attached to or cast onto a housing cover or the carrier plate, for example as a rivet or a bolt.
It is also possible to provide preferably at least one additional securing means which latches or locks the cable drum to the drive gear such that said drum is secured axially and radially on said drive gear. Thus for assembly the cable drum need only be pushed onto the drive gear, as a result of which axial securing is brought about automatically by latching or locking of said cable drum. In connection with this it is advantageous if the relevant additional securing means is formed integrally with the cable drum and/or the drive gear. Moreover, it is advantageous if the relevant additional securing means is designed as a clip connection, click connection or snap lock.
According to a further embodiment, the drive gear is completely accommodated in a sealed manner in a receptacle formed in the gear housing section, on the bottom of which a shaft mounting the drive gear only is provided or formed. It may also be advantageous if a front, free end of the shaft does not project above an upper edge of the receptacle. In such an embodiment, a circumferential seal for sealing the gear housing section may simply be fitted on the upper edge thereof or may be formed on said edge. In connection with this, a cylindrical section, the external diameter of which is smaller than the external diameter of the shaft, is also preferably provided on the front, free end of said shaft in order to make installation of the drive in the receptacle easier. Furthermore, the cable drum may also be completely covered by the shaft in an advantageous manner.
The invention and the advantages arising therefrom will be described in greater detail in the following on the basis of embodiments wherein reference will be made to the associated drawings:
Inside gear housing section 6 worm wheel 10 is rotatably mounted on a shaft 9 wherein shaft 9 according to the invention is designed to be so short that it does not project or projects only slightly out of worm wheel 10. Cable drum 17 coupled to gear wheel 10 is not penetrated by this shaft but is rotatably mounted so as to be shaftless or shaft-free. To secure the cable drum in both the axial and the radial direction at least one securing means is provided, here for example, an engagement executed as clip connection 19 which connects cable drum 17 to worm wheel 10. The securing means executed as clip connection 19 engage in the corresponding receivers on worm wheel 10. As a result cable drum 17 becomes fixedly and yet re-detachably connected to worm wheel 10 and in fact such that cable drum 17 is fixed without play in the axial and the radial direction at least. In the circumferential direction on the other hand, cable drum 17 can definitely illustrate a certain elastic play which has a damping effect when starting up or slowing down cable drum 17.
It is achieved by means of the structural design shown in
Gear housing section 6 or the gearbox section may preferably be provided with a short plastic shaft 9. This shaft 9 then essentially supports only worm wheel 10.
For further securing of cable drum 17, according to
By means of this shaftless structural design, not merely the design of the whole drive unit or of gear housing section 6 is variable but also the design of cable drum 17 itself. As
As in the previous embodiments, however, here too in the embodiment according to
As may be seen in all the FIGS., a centering device for cable drum 17 is provided on the free end of shaft 9 or the shaft stub. This is achieved by means of a graduation of the shaft stub. Worm wheel 10 may completely cover shaft stub 9. In this case the additional seal in this region may be dispensed with. Drive shaft 9 no longer protrudes into the window lift and also does not produce any new motor variant. Likewise, the use of a sheet metal sleeve may be dispensed with completely which also leads to a reduction in cost of the motor.
The following procedure is followed for installing a drive assembly according to the invention (cf.
Then cable drum 17 is coupled to drive gear 10 by means of a form-fitting engagement by way of claws or similar as disclosed by way of example in DE 103 42 074 A1 the contents of which are explicitly incorporated herein by way of reference for the purposes of disclosure. In this condition cable drum 17 is not yet secured axially and radially on the drive gear. Then cable drum 17 is wound with the cable and coupled to the cable window lift system (not shown).
Subsequently, the thrust bearing previously referred to is formed on drive gear 10 for securing cable drum 17 axially and radially. According to a first variation, for this purpose a bearing cover is placed on gear housing section 6 and fixedly joined to the drive unit such that said housing section is secured axially on the drive unit. As described previously, a protrusion or a projection, which is formed or provided on the bearing housing, co-operates with cup-shaped recess 70 or with the projection of cable drum 17 in such a manner that cable drum 17 is secured axially and radially on drive gear 10. By means of the thrust bearing thus formed, drive gear 10 is also secured axially on shaft 9 at the same time. Lateral cylindrical through openings are formed in the bearing cover for pushing the cable through from the cable drum receptacle thus formed. The bearing cover need not necessarily be designed as closed at all but may by way of comparison be designed as open. As described above, instead of such a bearing cover a web or bar may serve as the thrust bearing which is attached on the drive unit and encroaches diametrically on gear housing section 6 and cable drum 17 coupled to drive gear 10 in order to mutually secure drive gear 10 and cable drum 17 axially and in order at the same time to ensure that cable drum 17 is axially and radially secured in relation to drive gear 10. In this case, provided on the web or bar is a recess or a protrusion which co-operates with correspondingly formed cup-shaped recess 70 or a corresponding projection of cable drum 17 in order to form the thrust bearing.
Finally, the drive assembly thus assembled is installed in the vehicle door. To do this the drive assembly may be installed in the known manner on a carrier plate or a door module member and these are then inserted into an installation aperture of the vehicle door.
As described above, according to the invention, basically a carrier plate or a door module member may co-operate with cable drum 17 in order to form the thrust bearing in the manner previously described. Thus for installation in the case of such an embodiment, the drive unit with the cable drum attached is placed axially on the carrier plate or door module member and finally the drive unit is joined to the carrier plate or the door module member. Finally, the carrier plate or the door module member is inserted into the installation aperture of the vehicle door. So that drive gear 10 does not accidentally fall out of the drive unit during pre-assembly, a circumferential rib or a comparable securing means, which the drive gear is clipped onto, may be provided on shaft 9 to act as a captive securing means to prevent loss. So that cable drum 17 does not accidentally separate from drive gear 10 during pre-assembly, additional securing means, which are provided in the engagement region between cable drum 17 and drive gear 10, may secure cable drum 17 in relation to drive gear 10. For this purpose, the additional securing means may be designed as clips, latching elements or similar. These may basically be formed integrally with cable drum 17 and/or drive gear 10, especially on engagement claws or the like formed thereon, but may also, however, be used as additional securing elements in the engagement region.
As will be easily be obvious to the person of average skill in the art, the drive assembly according to the invention is also basically suitable in a corresponding manner for manually adjustable cable window lift systems of motor vehicles.
The description provided above is directed at particularly preferred embodiments of the invention. The object defined according to the claims nevertheless covers the numerous variations and modifications of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2007 005 143.3 | Apr 2007 | DE | national |
