ELECTROMOTIVE DRIVE FOR AUTOMOTIVE APPLICATIONS

Description

[0001] The invention relates to an electric motor drive for automotive applications, comprising an electric motor, further comprising a drive wheel, in particular a worm wheel, having a cam contour interacting with the electric motor, and comprising a lever acted upon by the cam contour, wherein the cam contour performs a full rotation (360°) to act upon the lever.

[0002] Electric motor drives for automotive applications are characterized by their robust design and the ability to operate with a low voltage, typically 12 V or 24 V DC. This often requires special measures to transmit the electric motor's rotary motion in order to realize even force-intensive operations. Such transmissions are typically achieved by the electric motor meshing with an external toothing of the worm gear via a worm located on its output shaft. In addition, the cam contour typically has a spiral edge to apply increasing torque to the lever, which is attached to the worm gear and can be actuated using the spiral edge of the cam contour.

[0003] This has proven fundamentally successful, which is why such electric motor drives are used, for example, to control a lock, as described in the generic DE 197 02 420 C5. Indeed, with the actuator or actuator realized in this way, the functional positions "open," "locked," "anti-theft device," and finally "child safety device" can be realized, which correspond to rotational movements of the worm gear of 0°, 360°, 90°, 180°, and finally 270°. This has proven fundamentally successful.

[0004] DE3319354A1 represents the closest state of the art.

[0005] In addition, comparable electric motor drives have recently been used to power locking actuators in charging devices in electric or hybrid vehicles. Other applications for such electric motor drives include raising and lowering a window pane, adjusting a mirror, or even adjusting a seat. Lid unlocking and locking mechanisms can also be implemented using these systems. In addition, such electric motor drives are used inside vehicle locks or as closing and opening drives. These drives are always characterized by a high-speed electric motor whose high rotational speed is converted into a relatively slow movement with increased power or torque and, consequently, a high gear ratio.

[0006] Intermediate gears can be used in this context. However, these increase the technological complexity and friction, and are therefore generally avoided and not considered effective. Nevertheless, there are still efforts to increase the gear ratio already available. There are currently no simple and cost-effective solutions available for this. The invention aims to remedy this situation.

[0007] The invention is based on the technical problem of further developing such an electric motor drive for automotive applications in such a way that an increase in the gear ratio is provided while simultaneously maintaining a simple and cost-effective design. To solve this technical problem, the invention proposes that the cam contour of a generic electric motor drive for automotive applications be configured to realize more than a full rotation (> 360°).

[0008] To prevent any collisions with a stationary stop, the cam contour is equipped with a flexible stop. The stop is a clamping device that interacts with the drive gear, particularly a worm gear. Advantageously, the drive gear is designed as a worm gear. It is also conceivable for the drive gear to be designed as a gear or similar.

[0009] The invention is based, first and foremost, on the realization that the cam contour can be used to achieve more than a full rotation, or rather, to apply it to transmit a further increased transmission ratio to the lever compared to the prior art. This enables the lever to execute the desired actuating movements with a torque that is increased compared to the prior art. This can involve the representation of functional states inside a motor vehicle lock, a closing or opening movement on a motor vehicle door, the raising or lowering of a motor vehicle window, etc., to name just a few application examples.

[0010] The flexible stop is implemented to ensure that the electric motor drive can be decelerated and stopped immediately after the associated actuating movement has been completed. This means that any "running movements" of the drive are not observed. With the help of such a flexible stop, the desired rotations of more than 360° of the cam contour can be easily implemented in practice, without the fear of any collisions with a stationary stop. Rather, the stop, advantageously designed as a clamping device that interacts with the drive wheel, in particular the worm wheel, represents a proven means of decelerating the cam contour and thus the drive wheel, in particular the worm wheel, at the end of its actuating movement or at the beginning after a reversing movement.Due to the flexibility of the clamping device, this braking process can also be considered "soft" compared to a "hard stop", so that such a characteristic has the additional advantage of avoiding any damage to the electric motor drive caused by a hard stop.

[0011] According to the invention, the clamping device is secured on the one hand to the drive wheel, in particular the worm wheel, and on the other hand to a stationary stop. Furthermore, the drive wheel, in particular the worm wheel, advantageously has a guide contour for the clamping device. With the help of the guide contour, the clamping device can thus be "wound up" onto the drive wheel, in particular the worm wheel. To prevent collisions with the cam contour at this point, the design is furthermore such that the guide contour is provided and arranged opposite the cam contour on the drive wheel, in particular the worm wheel.

[0012] This means that the cam contour and the lever adjacent to and interacting with it for actuating the desired actuating element are located on one side of the drive wheel, in particular the worm wheel, for example on its top side or front side. In contrast, the rear side of the drive wheel, in particular the worm wheel, is typically equipped with the guide contour. Since the clamping device is connected to the drive wheel, in particular the worm wheel, at one end, usually adjacent to the guide contour or even on the guide contour, a rotational movement of the drive wheel, in particular the worm wheel, causes the clamping device to contact the worm wheel around the guide contour and thus be wound onto the drive wheel, in particular the worm wheel.

[0013] In this context, it has proven particularly advantageous if the tensioning device is band-shaped. In principle, the tensioning device can also be a spring, for example a spiral spring. However, the invention generally uses a band-shaped tensioning device, which also and typically allows a flexible length change of more than 20%, preferably more than 50%. This means that the band-shaped tensioning device can be lengthened or stretched by more than 20%, more than 50%, or even more, without any damage being observed at this point.

[0014] For this purpose, the clamping device is advantageously made entirely or partially of an elastic material. Elastic plastics such as elastomers have proven particularly suitable for this purpose. In principle, the clamping device can also be made of a textile. Combinations of an elastomer with a textile, for example, are also conceivable.

[0015] The cam contour typically has a recess for the lever, preferably close to the axis. This means that the recess is located near or adjacent to the axis of the drive gear, especially the worm gear. A spiral edge or spiral contour of the cam contour generally extends from this recess. The spiral edge or spiral contour describes more than one full revolution around the previously mentioned axis of the drive gear, especially the worm gear.

[0016] If the cam contour is arranged in a plane, the cam contour has the aforementioned spiral edge in said plane, which acts with increasing radial distance on the lever to actuate the actuating element. In principle, however, a spiral contour can also be implemented at this point, which extends helically relative to the axis of the drive wheel / worm wheel and thus describes more than a full revolution around the axis. The helical shape of the spiral contour implies that the spiral contour, and with it the cam contour as a whole, is designed spatially or three-dimensionally. Even in such a case, the helical spiral contour again ensures that the lever interacting with it is acted upon by the spiral contour in order to initiate the desired movement of the actuating element.

[0017] The result is an electric motor drive for automotive applications that, thanks to its cam contour, is capable of achieving more than a full rotation. It is capable of transmitting a particularly high gear ratio from the electric motor via the drive gear, in particular the worm gear, and the cam contour to the lever for actuating the desired actuating element. For example, the lever may be directly or indirectly connected to a rotary latch in order to actuate it in a closing motion and thus close an associated motor vehicle door. Of course, other applications are also conceivable, which have already been described in the introduction.

[0018] The invention also relates to a motor vehicle lock, and in particular a motor vehicle door lock, equipped with such an electric motor drive. The drive can be used to electrically open the motor vehicle lock in question. This can be achieved indirectly by operating a release lever or directly by directly engaging the locking pawl. Furthermore, lock functions such as child safety locks, anti-theft devices, central locking, etc., can be implemented and implemented individually or in combination with the drive in question.

[0019] The drive gear, especially the worm gear, is usually designed as an injection-molded part, allowing the drive gear, especially the worm gear, including the cam contour, to be manufactured particularly easily and cost-effectively. Metal or plastic versions have proven successful in this regard. In conjunction with the flexible stop, designed as a band-shaped clamping device, a particularly simple design is provided and implemented, which also results in low manufacturing costs. These are the key advantages.

[0020] In the following, the invention is explained in more detail with reference to a drawing which merely represents an exemplary embodiment, in which: Fig. 1A and 1B a front view of the electric motor drive according to the invention in two different functional positions and Fig. 2A to 2C the electric motor drive according to the Fig. 1A and 1B in a rear view.

[0021] The figures depict an electric motor drive for automotive applications. For this purpose, the drive in question comprises an electric motor 1, which is typically operated with a low DC voltage of, for example, 12 V, 24 V, or 48 V. The electric motor 1 has an output worm 2 arranged on its output shaft, which meshes with the external toothing of a worm wheel 3. As a result, the worm wheel 3 can be used, particularly in the Fig. 1A and 1B perform the counterclockwise movements around its axis 4 as shown. The counterclockwise movement in the front view according to the Fig. 1A and 1B corresponds to a clockwise movement in the rear view according to the Fig. 2A to 2C . In principle, clockwise movements in the front view and correspondingly counterclockwise movements in the rear view are also conceivable.

[0022] The worm wheel 3 is equipped with a spiral cam contour 5. The cam contour 5 has a recess 6 near the axis on the one hand and a spiral edge 7 on the other hand. The spiral edge 7 extends from the recess 6 and is characterized by a in the direction of actuation (counterclockwise in the front view according to the Fig. 1A and 1B ) increasing radius, so that a lever 8 acted upon by the cam contour 5 experiences an increasing torque load. In fact, the lever 8 is a two-arm lever made of, for example, plastic or metal, which is mounted in a housing so as to be rotatable about a central axis 9 according to the exemplary embodiment. The housing can be the housing of a motor vehicle lock or a closing drive, window lift drive, flap drive, etc.

[0023] According to the exemplary embodiment, an actuating element 10 is actuated by means of the lever 8. In the case of a closing drive, the actuating element 10 can be a rotary latch (not expressly shown) of the previously mentioned motor vehicle door lock. In principle, however, the actuating element 10 can also be a window pane that can be raised and lowered, a motor vehicle door, a motor vehicle hatch, etc. For this purpose, the lever 8 is able to Fig. 1B which, according to the embodiment, corresponds to the lever 8 moving from its initial position in the Fig. 1A clockwise around its axis 9, as can be seen when comparing the Fig. 1A and 1B can understand.

[0024] The special feature of the invention is that the cam contour 5 for acting on the lever 8 can not only perform a movement in the sense of a full rotation of 360°, as can be seen when comparing the Fig. 1A and 1B In fact, in the Fig. 1A the initial position of the cam contour 5 is shown as 0°, whereas in the Fig. 1B The final position of cam contour 5 is shown, which corresponds to an angle of more than 360°. In fact, in the example shown, a total angle of almost 400° is completed, namely 360° plus approximately 35°. This is, of course, only an example and is by no means limiting.

[0025] This means that, according to the invention, the cam contour 5 is configured to realize a more than full rotation of over 360° around the associated axis 4 of the worm gear 3. To realize and implement this in detail, the two-armed lever 8 inserts one arm 8a into the previously mentioned recess 6 of the cam contour 5. The other arm 8b of the two-armed lever 8, in contrast, acts directly or indirectly on the merely indicated actuating element 10, as desired. The actuating element 10 can be the previously mentioned rotary latch, the window pane, a motor vehicle door, etc.

[0026] Starting from the basic position after the Fig. 1Aand the setting angle of 0° for the cam contour 5, a rotational movement of the worm gear 3 and thus of the cam contour 5 around the axis 4 in a counterclockwise direction causes the spiral edge 7 of the cam contour 5 to move against the arm 8a of the lever 8. In the example shown, the cam contour 5 and thus the spiral edge 7 extend in a plane parallel to the worm gear 3. Due to the increasing distance of the spiral edge 7 from the axis 4 of the worm gear 3, the arm 8a of the lever 8 is increasingly pivoted around the axis 9, specifically in a clockwise direction, and the actuating element 10 is thereby subjected to the desired load.

[0027] Because the cam contour 5 completes a more than full rotation of over 360° during this process, the overall transmission ratio provided by the electric motor 1 can be increased, which ultimately acts on the lever 8. In order to be able to brake and stop the electric motor 1 precisely at the end of this movement, a flexible stop 11 is additionally implemented, which can be seen from the rear view according to the Fig. 2A to 2C can understand.

[0028] In fact, the stop 11 is designed as a clamping device 11 that interacts with the worm gear 3. For this purpose, the clamping device 11 is fixed on the one hand to the worm gear 3 and on the other hand to a stationary stop 12. The worm gear 3 also has a guide contour 13 for the clamping device 11. In the exemplary embodiment, the guide contour 13 is a ring or annular contour that surrounds the axis 4 of the worm gear 3 at a distance. It can be seen that the clamping device 11 is fixed at one end to the guide contour 13 or engages in the guide contour 13, whereas the other end of the clamping device 11 is connected to the stationary stop 12.

[0029] The overall design and furthermore is such that the cam contour 5 is arranged and placed on the front side or top side of the worm wheel 3, which can be seen when looking at the Fig. 1A and 1BIn contrast, the guide contour 13 is located on the back of the worm wheel 3, as can be seen from the rear view according to the Fig. 2A to 2C The cam contour 5 and the guide contour 13 are manufactured as a single piece with the worm gear 3, for example, as an injection-molded part. This can be made of plastic and / or metal.

[0030] The Fig. 2A to 2Cmake it clear that the clamping device 11 is band-shaped. In addition, the band-shaped clamping device 11 allows a flexible change in length of more than 20%, preferably 50% or more. This means that when the band-shaped clamping device 11 is subjected to an axial load, it is able to increase its length by more than 20% and preferably even by 50% or more, and can still return to its original state flexibly and without damage after the axial load has ended. For this purpose, the clamping device 11 is made entirely or partially from an elastic material. This can be an elastomeric plastic, for example NR (natural rubber). In principle, a textile or combinations are also conceivable in this case.

[0031] In any case, the Fig. 1A and 1BThe action of the lever 8 shown in the front view by means of the cam contour 5 moving counterclockwise results in the corresponding clockwise movement of the worm wheel 3 in the rear view according to the Fig. 2A to 2C The clockwise movement now corresponds to the fact that the clamping device 11 is placed circumferentially on the annular guide contour 13 and is wound onto the guide contour 13, as can be seen in the sequence of Fig. 2A to 2C This also applies in principle when the worm gear 3 performs a reversing movement in a counterclockwise direction.

[0032] Not shown is the further possibility that the cam contour 5 does not have a spiral edge 7 oriented in the plane, but is instead equipped with a helical spiral contour. In this case, the arm 8a of the lever 8 equipped with the cam contour 5 can, for example, be equipped with a roller that follows the helical spiral contour of the cam contour 5. In this case, the two-armed lever 8 does not perform a pivoting movement about its axis 9, but rather is moved upwards about an axis lying in the plane of the drawing, so that as a result, the other arm 8b performs a downward movement, which in turn can be transmitted to the actuating element 10. List of reference symbols 1 electric motor 2 Output screw 3 Drive wheel / worm wheel 4 axis 5 Cam contour 6 Recess (near the axis) 7 Spiral edge 8 two-armed lever 8a first arm 8b second arm 9 (middle) axis 10 Actuator 11 flexible stop / clamping device 12 Stop (stationary) 13 Guide contour

Claims

1. Electromotive drive for motor vehicle applications, comprising an electric motor (1), further comprising a drive wheel (3), in particular a worm wheel (3), which interacts with the electric motor (1) and has a cam contour (5), and comprising a lever (8) which can be acted upon by the cam contour (5), the cam contour (5) completing a full revolution (360°) in order to act upon the lever (8), characterized in that the cam contour (5) is designed to complete more than a full revolution (> 360°), the cam contour (5) being equipped with a flexible stop (11), the stop (11) being designed as a tensioning means (11) which interacts with the drive wheel (3), in particular the worm wheel (3), the drive wheel, in particular the worm wheel (3), having a guide contour (13) for the tensioning means (11).

2. Drive according to claim 1, characterized in that the tensioning means (11) is fixed at one end to the drive wheel (3), in particular the worm wheel (3), and at the other end to a stationary stop (12).

3. Drive according to claim 1, characterized in that the guide contour (13) is provided opposite the cam contour (5) on the worm wheel (3).

4. Drive according to any of claims 1 to 3, characterized in that the tensioning means (11) is in the form of a band and allows a flexible length change of more than 20%, preferably of 50% and more.

5. Drive according to any of claims 1 to 4, characterized in that the tensioning means (11) is made entirely or partially of an elastic material, for example an elastomer, a textile or combinations.

6. Drive according to any of claims 1 to 5, characterized in that the cam contour (5) has a recess (6), preferably close to the axis, for the lever (8).

7. Drive according to any of claims 1 to 6, characterized in that the cam contour (5) has a spiral edge (7) which describes more than a full revolution about the axis (4).

8. Motor vehicle latch, in particular a motor vehicle door latch, characterized by an electromotive drive according to any of claims 1 to 7.