Electric-motor drive unit for motor vehicle applications

Abstract

The invention relates to an electric-motor drive unit for motor vehicle applications and in particular to a closing-aid actuator. The drive unit has, in its basic construction, an electric motor (5), a gear train (6, 7, 8, 9, 10) which is downstream of the electric motor (5), and an actuating element (4) which follows the gear train (6, 7, 8, 9, 10). The gear train (6, 7, 8, 9, 10) comprises at least one spur-gear gear train stage (7, 10) having a ring gear (7) and having a gear (10) which meshes with the ring gear (7) and which rotates about a shaft. According to the invention, the shaft of the gear (10) in question is supported on a contour (11) of the ring gear (7).

Description

[0001] Description

[0002] Electric motor drive unit for automotive applications

[0003] The invention relates to an electric motor drive unit for automotive applications, in particular a closing aid actuator, comprising an electric motor, a transmission connected downstream of the electric motor and an actuating element following the transmission, wherein the transmission has at least one spur gear stage with a ring gear and a gear engaging in the ring gear and rotating about an axis.

[0004] Electric motor drive units for automotive applications are typically characterized by low-voltage direct current operation. For this reason, it is usually necessary to reduce the rotary movements of the electric motor using the downstream gearbox. This allows compact and cost-effective electric motors to be used even for energy-intensive actuating movements. These actuating movements are monitored by the actuating element following the gearbox. This actuating element can be a mechanical intermediate element that converts the rotary actuating movements of the gearbox into, for example, a pivoting movement or a linear adjustment.

[0005] In fact, such electric motor drive units are used in a wide variety of applications in the automotive sector, and the number is increasing. Examples of such applications include mirror adjustments, seat adjustments, window lifts, charging socket locks, etc. In conjunction with a motor vehicle lock, such an electric motor drive unit can be used, in particular, as a closing aid actuator. In this case, the drive unit in question operates, for example, on a locking element, which engages a rotary latch and ensures that the rotary latch is actuated in a closing direction.

[0006] WO 2004 / 040089 A1 concerns the actuation of a pawl using such an electric motor drive unit. This allows the pawl to be actuated and, in particular, released from its engagement with the rotary latch. This generally causes the locking mechanism to enter its open state.

[0007] In a similar electric motor drive unit according to DE 10 2020 121 519 A1, a standard-voltage motor for electromechanically actuating an actuating mechanism and at least one additional low-voltage motor are provided. The drive train for electromechanical actuation implemented here is equipped with a gearbox with two gear ratios. The gearbox can be designed as a spur gear.

[0008] The generic prior art according to EP 1 074 681 A1 proceeds in such a way that the motor vehicle door lock described therein is equipped with an electric drive motor that, during normal operation, operates in only one direction of rotation and with a low reduction ratio via a normal actuating element on a locking pawl. In emergency operation and in the opposite direction of rotation, the electric drive motor operates with a significantly higher reduction ratio via an emergency actuating element on the locking pawl in question. For this purpose, the reduction gear is designed as a planetary gear.

[0009] The planetary gear set has a ring gear, into which individual planetary gears mesh, which in turn actuate an additional sun gear. The individual planetary gears are mechanically connected to one another via a planetary gear carrier. This results in a bulky and complicated structure. The invention aims to remedy this overall problem. The invention is based on the technical problem of further developing such an electric motor drive unit for automotive applications, and in particular a power closing actuator, in such a way that the greatest possible torque can be transmitted in a small installation space.

[0010] To solve this technical problem, a generic electric motor drive unit for automotive applications is characterized according to the invention in that the axis of the gear meshing with the ring gear is mounted on a contour of the ring gear. The axis of the ring gear is preferably supported both axially and radially by means of the contour.

[0011] In this way, at least one gear stage or spur gear of the transmission is initially equipped with the ring gear and the gear meshing therewith. The gear stage in question is usually the last gear stage of the transmission, i.e., the one on the output side of the transmission that operates on the actuator actuated by it. Furthermore, the observed torque is greatest at this last gear stage.

[0012] Since the gear stage in question is designed according to the invention such that a gear meshes with the ring gear, and both the ring gear and the gear meshing with the ring gear rotate about an axis, the ring gear and the gear can be arranged with a small axial distance from each other. In any case, the axial distance of the two parallel axes, on the one hand, of the ring gear and, on the other hand, of the gear meshing with the ring gear, is smaller than the axial distance observed when the gear in question does not mesh with the ring gear, but rather meshes with an external toothing of the ring gear.

[0013] The ring gear is usually directly or indirectly coupled to the actuating element. This already provides a particularly compact design. In this case, the actuating element can be designed as an attachment that is connectable or connected to the ring gear and corresponds in size to the ring gear. A flexible connecting element, such as a cable, can then be connected to the corresponding attachment. The cable can be used to close a locking mechanism of a remote motor vehicle lock. For this purpose, the cable can be mechanically coupled from the attachment directly to a rotary latch or indirectly to the rotary latch via intermediate elements in order to apply a closing force to the locking mechanism in the pre-locking position.

[0014] The compact design is now enhanced by the fact that the gear meshing with and driving the ring gear does not protrude laterally beyond the ring gear. Nevertheless, a high torque can be transmitted, which, in the example described, is used to actuate the cable connected to the attachment.

[0015] Since the ring gear and the cup- or lid-like attachment are generally coupled to one another in a rotationally fixed manner, while the gear meshing with the ring gear rotates along the internal toothing in the ring gear, it is generally necessary to support the axis of the gear meshing with the ring gear, which is free in the direction of the attachment. According to the invention, this is ensured by the contour of the ring gear, on which the axis of the gear meshing with the ring gear is mounted. The additional guide ensures that the axis of the driving gear meshing with the ring gear is generally perfectly guided and held on both sides, both radially and axially.

[0016] The previously mentioned contour of the ring gear guides the free end of the axle or a guide pin provided at this point. The opposite end of the axle or the guide pin of the gear is generally connected to another gear, or the guide pin for both gears can, for example, be supported against a housing that houses the electric motor drive unit. The housing may have a modular design so that the electric motor drive unit can be arranged and positioned at virtually any location, for example inside a motor vehicle door. The actuating movements provided by the electric motor drive unit are transmitted via the attachment, which rotates together with the ring gear, to the cable pull and, in particular, the Bowden cable, which is detachably connected to the attachment.

[0017] Using the cable or Bowden cable, the desired elements in or on the vehicle can then be moved. This can be, but is not limited to, the rotary latch of a locking mechanism, thus implementing a power closing actuator. In principle, however, any other actuating movement can also be realized using the electric motor drive unit according to the invention, for example, the previously mentioned mirror adjustment, seat adjustment, window movement, etc.

[0018] To realize and implement this in detail, the contour of the ring gear, especially for supporting the free axis of the gear, is generally annular. Furthermore, the design is usually such that the contour in question and the ring gear are arranged concentrically around a common axis. The cup-shaped attachment is also generally arranged concentrically around this common axis and is connected to the ring gear in a rotationally fixed manner.

[0019] Furthermore, the design is advantageously such that the contour is arranged at a distance from the ring gear of the ring gear inside the ring gear. In particular, the gear meshing with the ring gear, with the guide pin defining the axis, ensures that the guide pin in question slides in a rotating manner along the contour of the ring gear. In this context, the design is also such that the guide pin engages over the gear on the head side. This allows the guide pin, which is typically arranged in the center of a ring gear of the gear, to engage over the ring gear of the gear meshing with the ring gear. As a result, the design is particularly advantageously such that the contour at least partially engages over the ring gear of the gear in question.

[0020] This means that the guide pin defining the axis of the gear meshing with the ring gear projects over the gear rim of the gear with its head end. This allows the head end of the guide pin to interact with the contour of the ring gear and, in particular, to rotate and slide along the contour in question during a rotational movement of the gear meshing with the ring gear. At the same time, the design is advantageously such that the contour, due to the projecting nature of the free end of the guide pin, at least partially overlaps and can also overlap the gear rim of the gear meshing with the ring gear. This provides additional axial securing for the guide pin and with it the gear meshing with the ring gear. This is because the gear rim of the gear moves, as it rotates along the internal toothing of the ring gear, "underneath" the contour of the ring gear, which at least partially overlaps the gear rim.

[0021] A cost-effective and weight-optimized design is further characterized by the contour and the ring gear being constructed from a single material. The same can apply to the pot-shaped attachment. A one-piece design of the attachment, including the ring gear and contour, made of plastic has proven particularly advantageous. The gear meshing with the ring gear and the other gears of the transmission downstream of the electric motor can also be made of plastic. The individual spur gears of the meshing gears of the transmission can mesh with each other via spur or helical gearing. Combinations are also conceivable. In most cases, the transmission is designed to have a total of two spur gear stages.While the first gear stage, used to transmit rotary motion from a worm gear to an electric motor output shaft, is equipped with helical gearing to suppress any noise emanating from the electric motor and minimize running noise, the subsequent second gear stage, in contrast, is equipped with straight gearing. This subsequent gear stage is the final or last gear stage of the transmission, equipped with the ring gear and the engaging drive gear.

[0022] This allows for the provision and realization of particularly high overall transmission ratios or overall reduction ratios, providing values ​​of more than 100:1, and in particular even more than 300:1. As a result, a compact and particularly cost-effective electric motor can be used, which, even in conjunction with a closing aid actuator, provides the power required for the closing function. This means that, for example, a conventional electric motor can be used as the electric motor, such as those previously and typically used inside motor vehicle locks for (central) locking functions.

[0023] The result is an electric motor drive unit for automotive applications, and in particular a closing aid actuator, which has a compact and cost-effective design, yet delivers a high torque on the output side, which even provides the forces required for a closing function. This can ultimately be explained by the combination of the ring gear with the engaging drive gear in conjunction with the last gear stage. The contour of the ring gear also ensures that the gear axis is mounted on the corresponding contour of the ring gear. This applies in particular to a free end of the gear axis or the component of the guide pin that overlaps the gear ring on the head side.

[0024] The invention is explained in more detail below with reference to a drawing which merely represents an exemplary embodiment; in the drawings:

[0025] Fig. 1 shows the electric motor drive unit according to the invention in a perspective overview with the housing partially opened,

[0026] Fig. 2 shows the object according to Fig. 1 in the area of ​​the electric motor including the gearbox in detail and

[0027] Fig. 3 shows a detail from Fig. 2 with the ring gear provided according to the invention including the annular contour provided thereon.

[0028] The figures show an electric motor drive unit for automotive applications. With the help of the drive unit, which is shown in an overall overview in Fig. 1, a motor vehicle lock 1, which is only indicated here and is arranged remotely from the electric motor drive unit, can be actuated, for example. The motor vehicle lock 1 is equipped inside with a locking mechanism (not shown), which can be closed using the electric motor drive unit according to Fig. 1. To do this, the locking mechanism is first moved into a pre-locking position and then closed using the electric motor drive unit shown. For this purpose, the drive unit in question works by way of example and not as a rotary latch as a component of the locking mechanism inside the motor vehicle lock 1. This is described in detail in DE 10 2013 108 156 A1, which can be cited as a reference.The electromotive drive unit according to Fig. 1 is equipped overall with an enclosing housing 2, which has or can have a lower housing shell shown here and an upper housing shell closing the lower housing shell. This allows the drive unit as a whole to be mounted in a modular manner and at practically any location, for example inside a motor vehicle door. In the exemplary embodiment, a cable 3, which is or can be designed as a Bowden cable, ensures the mechanical coupling between the drive unit and the motor vehicle lock 1. With the help of the cable 3, linear adjusting movements can be transmitted to the motor vehicle lock 1, with the help of which the rotary latch of the locking mechanism is transferred from a pre-locking position to a main locking position, comparable to the previously mentioned prior art according to DE 10 2013 108 156 A1.

[0029] This is of course only an example and is in no way restrictive. This means that, in addition to the illustrated embodiment of the electromotive drive unit as a closing aid actuator, other adjusting movements can of course also be implemented with the respective drive unit. For this purpose, the drive unit is equipped with an adjusting element 4, which, according to the exemplary embodiment and not restrictively, is an attachment 4. Fig. 1 shows that the cable pull 3 is inserted with one end of its cable into a recess in the adjusting element 4 or attachment 4. As a result, rotary movements of the attachment 4 in the clockwise direction indicated here in Fig. 1 result in the cable of the cable pull 3, for example, pulling on the rotary latch inside the motor vehicle lock 1 and moving it from the pre-locking position to the main locking position.

[0030] To implement and realize this in detail, the drive unit previously shown in the overview in Fig. 1 is equipped with an electric motor 5. A gear 6, 7, 8, 9, 10 is connected downstream of the electric motor 5. For this purpose, the electric motor 5 operates via a worm 8 arranged on its output shaft on an intermediate gear 9, which, according to the exemplary embodiment, is designed as a double gear 9 and meshes with a first gear stage 6. The first gear stage 6 is in turn designed as a double gear and has a gear 10 that meshes with a ring gear 7.

[0031] It can be seen that the gears 6, 7, 9, 10 are all designed as spur gears, and consequently the transmission 6, 7, 8, 9, 10 is designed as a spur gear. The ring gear 7 provided within the final or last or second gear stage 7 is now rotationally fixedly coupled to the previously mentioned attachment 4 as the actuating element 4. As a result, rotational movements of the ring gear 7 directly result in the attachment 4 being acted upon, for example, performing the counterclockwise movement shown in Fig. 1, so that with the aid of the attachment or actuating element 4, the cable pull 3 is subjected to a pulling force as described.

[0032] It can be seen that the worm 8, the intermediate gear 9, and the first gear stage 6 each have helical gearing. This provides a noise-optimized profile of the gears 6 to 10. In contrast, the last or second gear stage 7 on the output side is equipped with helical gearing. Furthermore, the design in this context is such that the spur gear stage or last gear stage 7 is equipped with the ring gear 7 and the gear 10 that engages with the ring gear 7 and rotates about an axis. This already provides a compact structure because the gear 10, for example, does not mesh on the outside with the teeth of the ring gear 7. Furthermore, the ring gear 7 can be arranged and positioned in overlap with the first gear stage 6 or the double gear 6 implemented at this point. Overall, this also leads to the following, as can be seen from Fig.1. This is because the attachment or adjusting element 4 is connected to the ring gear 7, which in the exemplary embodiment is designed to be disc- or pot-shaped and whose dimensions correspond to those of the ring gear 7. In this way, the surface area of ​​the housing 2 for accommodating the electromotive drive unit according to the invention is ultimately determined and specified only by the external dimensions of the electric motor 5, the intermediate gear 9, and finally the ring gear 7. This leads to the small and compact design already described. A further contribution to this is that the rotary movements of the output shaft of the electric motor 5 or its output-side worm 8 can be reduced by the selected gear design, taking into account a reduction ratio of more than 100:1, in particular even more than 300:1.As a result, a small-sized, cost-effective electric motor 5 that is available in large quantities can be installed, as already described in the introduction.

[0033] According to the invention and as shown in Figs. 2 and 3, the design is such that the axis of the gear 10 is mounted entirely on a contour 11 of the ring gear 7, which has been omitted from the illustration in Fig. 2 for reasons of clarity, but is expressly shown in Fig. 3. This means that the ring gear 7 is additionally equipped with the contour 11 in question in an intermediate region between the outer peripheral toothing and a central region 12 defining the axis of the ring gear 7. The contour 11 now serves to mount the axis of the gear 10 engaging with the ring gear 7.

[0034] In fact, for this purpose, the gear 10 is equipped with a guide pin 13, which can be seen particularly in Fig. 3 and which overlaps a gear rim of the gear 10 on the head side. The guide pin 13 not only defines the axis of the gear 10 engaging with the ring gear 7, but also the axis of the gear 6 interacting with the gear 10 and functions as a continuous guide pin 13 for the double gear 6, 10 realized at this point. The guide pin 13 in question can be supported on the base side on a housing shell or a corresponding receiving bore in the lower housing shell shown in Fig. 1. The upper end of the guide pin 13 and thus also of the axis of the gear 10 engaging with the ring gear 7 is, however, free. In order to nevertheless realize and implement a perfect guidance of the axis of the gear 10 and thus of the guide pin 13 at this point, the contour 11 is provided on the ring gear 7.In this context, the contour 11 ensures axial and radial support of the guide pin 13 and thus of the axis of the gear 10.

[0035] It can be seen that the contour 11 is annular. In fact, the contour 11, like the ring gear 7, is arranged concentrically to the common axis, which runs centrally through the central element or central region 12 of the ring gear 7. Furthermore, the contour 11 in question is arranged at a distance from the ring gear of the ring gear 7 inside the ring gear 7.

[0036] The gear 10 meshing with the ring gear 7 is now guided by the guide pin 13, which rotates along the contour 11 in question. This provides radial support for the guide pin 13. The design is also such that the guide pin 13 overlaps the gear 10 in question or a gear ring provided at this location on the head side. In this context, the guide pin 13 is arranged in the center of the previously described gear ring of the gear 10. This additionally provides axial support for the gear 10 in question.

[0037] An examination of Fig. 3 makes it clear that the contour 11 of the ring gear 7 at least partially overlaps the relevant gear ring of the gear 10. This can be attributed to the fact that the guide pin 13 not only overlaps the relevant gear ring on the head side, but is also equipped with a diameter beyond which the individual teeth of the gear ring of the gear 10 protrude. As a result, the contour 11 can overlap at least two teeth of the relevant gear ring of the gear 10 engaging the ring gear 7. In this way, the relevant gear 10 is additionally axially secured.

[0038] This means that the contour 11 of the ring gear 7 not only ensures guidance or radial support of the gear 10 engaging in the ring gear 7 along the contour 11, but also ensures that the guide pin 13 or the gear 10 in question is secured axially between, on the one hand, a bearing point (not shown) in the lower housing shell of the housing 2 and, on the other hand, by the contact of individual teeth on the underside of the contour 11 in the relevant axial direction.

[0039] For reasons of simple and cost-effective production, the contour 11 and the ring gear 7 are generally made of a single material, for example, from plastic. The same applies to the other gears of the transmission 6, 7, 8, 9, 10. It is understood that the housing 2 can, if necessary, house the illustrated electromotive drive unit in a media-tight manner, for which purpose a seal (not shown) inserted into a groove 14 of the lower housing shell of the housing 2 shown in Fig. 1 may ensure this. This allows the entire electromotive drive unit to be housed as a modular power closing actuator, for example, in the so-called wet space inside a motor vehicle door. In such a case, the cable pull 3 is simultaneously introduced into the housing 2 in question via a sealing grommet 15 to ensure the media-tight design.According to the invention, this modular character is combined with a high reduction ratio, a compact design, and a particularly cost-effective embodiment, which, taken as a whole, represent the essential advantages. List of reference symbols.

[0040] Motor vehicle lock 1

[0041] Housing 2

[0042] Cable pull 3

[0043] Essay 4

[0044] Control element 4

[0045] Electric motor 5

[0046] Gearboxes 6, 7, 8, 9, 10

[0047] Gear stage 6

[0048] Gear stage 7

[0049] Ring gear 7

[0050] Snail 8

[0051] Intermediate gear 9

[0052] Double gear 9

[0053] Gear 10

[0054] Contour 11

[0055] Central Area 12

[0056] Guide pin 13

[0057] Slot 14

[0058] Sealing grommet 15

Claims

Patent claims 1. Electromotive drive unit for automotive applications, in particular a closing aid actuator, with an electric motor (5), a gearbox (6, 7, 8, 9, 10) connected downstream of the electric motor (5) and an actuating element (4) following the gearbox (6, 7, 8, 9, 10), wherein the gearbox (6, 7, 8, 9, 10) has at least one spur gear stage (7, 10) with a ring gear (7) and a gear (10) engaging in the ring gear (7) and rotating about an axis, characterized in that the axis of the gear (10) is mounted on a contour (11) of the ring gear (7).

2. Drive unit according to claim 1, characterized in that the contour (11) is annular.

3. Drive unit according to claim 1 or 2, characterized in that the contour (11) and the ring gear (7) are arranged concentrically to a common axis.

4. Drive unit according to one of claims 1 to 3, characterized in that the contour (11) is arranged at a distance from a toothed ring of the ring gear (7) in the interior of the ring gear (7).

5. Drive unit according to one of claims 1 to 4, characterized in that the gear (10) engaging in the ring gear (7) slides along the contour (11) in a rotating manner with a guide pin (13).

6. Drive unit according to claim 5, characterized in that the Guide pin (13) overlaps the gear (10) on the head side.

7. Drive unit according to claim 5 or 6, characterized in that the guide pin (13) is arranged in the center of a gear ring of the gear wheel (10).

8. Drive unit according to claim 7, characterized in that the contour (11) of the ring gear (7) at least partially overlaps the gear ring of the gear wheel (10).

9. Drive unit according to one of claims 1 to 8, characterized in that the contour (11) and the ring gear (7) are formed of the same material.

10. Drive unit according to one of claims 1 to 9, characterized in that the adjusting element (4) is designed as a preferably hood-like or pot-like attachment (4) which is non-rotatably coupled to the ring gear (2).

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