Electric drive unit for motor vehicle

Abstract

The invention relates to an electric drive unit for a motor vehicle, in particular a locking assist actuator. The drive unit comprises, in its basic structure: a motor (5); transmission mechanisms (6, 7, 8, 9, 10) connected downstream of the motor (5); and an adjusting element (4) downstream of the transmission mechanism (6, 7, 8, 9, 10). The transmission mechanism (6, 7, 8, 9, 10) has at least one spur gear transmission stage (7, 10) which comprises a ring gear (7) and a gear (10) which engages in the ring gear (7) and which rotates about an axis. According to the invention, the shaft of the associated gearwheel (10) is supported on the profile (11) of the ring gear (7).

Description

Technical Field

[0001] The present invention relates to an electric drive unit for a motor vehicle, in particular a closing assist actuator, comprising: an electric motor; a transmission mechanism connected downstream of the electric motor; and an adjusting element downstream of the transmission mechanism, wherein the transmission mechanism has at least one spur gear transmission stage, the at least one spur gear transmission stage comprising a ring gear and a gear engaged in the ring gear and rotating about an axis. Background Art

[0002] Electric drive units for motor vehicles are often characterized by low-voltage DC operation. For this reason, the motor's rotational motion is often decelerated by a downstream transmission. This allows a compact and cost-effective motor to be used for energy-intensive actuating movements. These actuating movements are performed on an actuating element downstream of the transmission. This actuating element can be a mechanical intermediate element that converts the transmission's rotary actuating motion, for example, into a pivoting motion or linear displacement.

[0003] In practice, such electric drive units are used in a wide variety of applications and are increasingly being used in the automotive sector. Examples of such applications include mirror adjustment, seat adjustment, window lift systems, and charging socket locks. In conjunction with vehicle locks, such electric drive units can be designed, in particular, as closing assistance actuators. Here, the drive unit acts, for example, on a locking element that engages a locking tongue and ensures that the tongue is loaded in the tensioning direction.

[0004] The scope of WO 2004 / 040089 A1 relates to the manipulation of the pawl by means of such an electric drive unit. Thus, the pawl can be manipulated and, in particular, disengaged from its engagement with the bolt. Thus, the locking mechanism is usually transitioned to its open state.

[0005] A similar electric drive unit, corresponding to DE 10 2020 121 519 A1, includes a conventional high-voltage motor and at least one additional low-voltage motor for electromechanically actuating an operating mechanism. The drive train implemented here for electromechanical actuation is equipped with a transmission with two speed stages. The transmission can be designed as a spur gear transmission.

[0006] According to the prior art described in EP 1 074 681 A1, the motor vehicle door lock described therein is equipped with a drive motor that, during normal operation, acts on the pawl only in the direction of rotation and at a low reduction ratio via a conventional actuating element. During emergency operation, the drive motor acts on the relevant pawl via the emergency actuating element in the opposite direction of rotation and at a significantly higher reduction ratio. For this purpose, the reduction gear mechanism is specifically designed as a planetary gear mechanism.

[0007] A planetary gear train has a ring gear in which the individual planetary gears engage, which in turn load the additionally provided sun gear. The individual planetary gears are mechanically connected to one another via a planetary carrier. This results in a cumbersome and complex design. The present invention aims to remedy this problem overall. Summary of the Invention

[0008] The object of the present invention is to develop an electric drive unit of this type for a motor vehicle, in particular a closing assist actuator, in such a way that the greatest possible torque can be transmitted in a small installation space.

[0009] In order to solve this technical problem, this type of electric drive unit for motor vehicles is characterized in that the shaft of the gear engaged in the ring gear is supported on the profile of the ring gear. Here, the shaft of the ring gear is preferably supported axially and radially by the profile.

[0010] In this way, at least one transmission stage of the transmission, or rather the spur gear transmission, is initially equipped with a ring gear and a gear engaging therewith. This transmission stage is usually the last transmission stage of the transmission, i.e., the stage that acts on the actuating element loaded by it on the output side of the transmission. Furthermore, the highest torque is achieved at the last transmission stage.

[0011] Since the transmission stage in question is designed according to the invention such that the gearwheel engages in the ring gear, and the ring gear and the gearwheel engaged in the ring gear rotate about an axis, the ring gear and the gearwheel can be arranged with a smaller axial distance relative to one another. In any case, the axial distance between the two axes running parallel to one another, the ring gear on the one hand and the gearwheel engaged in the ring gear on the other hand, is smaller than the axial distance that would be achieved if the gearwheel in question did not engage in the ring gear, but rather meshed with the outer toothing of the ring gear.

[0012] The ring gear itself is usually connected indirectly or directly to the adjustment element. This provides a particularly compact design. Therefore, in this case, the adjustment element can be designed as a cover part that is connected or connectable to the ring gear and that corresponds in size to the ring gear. In this case, a flexible connection element, such as a cable, can also be connected to the corresponding cover part itself. The cable can be used to close the locking mechanism of a motor vehicle lock that is remote from it. To this end, the cable can be mechanically connected directly to the lock tongue from the cover part or indirectly to the lock tongue via an intermediate element, so as to load the lock tongue in the tensioning direction when it is in the pre-locking position of the locking mechanism.

[0013] The compact design is now improved according to the invention by the fact that the gears which engage in the ring gear and drive the ring gear do not protrude laterally from the ring gear. Nevertheless, high torques can be transmitted, by means of which the cables connected to the cover element are loaded in the exemplary case.

[0014] Because the ring gear and the pot-shaped or cap-shaped cover are typically connected to each other in a rotationally fixed manner, and the gear engaged in the ring gear rotates along the internal toothing in the ring gear, it is usually necessary to support the free shaft of the gear engaged in the ring gear toward the cover. According to the present invention, a profile in the ring gear ensures this, on which the shaft of the gear engaged in the ring gear is supported. The additional guidance ensures that the shaft of the drive gear engaged in the ring gear is generally well guided and secured on both sides, namely radially and axially.

[0015] The previously mentioned shaped portion of the ring gear ensures guidance of the free end of the shaft or guide pin provided therein. Conversely, the opposite end of the shaft or guide pin of the gear is typically coupled to another gear, or the guide pins for both gears can be supported relative to a housing that accommodates the electric drive unit. The housing can be designed modularly, allowing the electric drive unit according to the present invention to be arranged and installed in virtually any location, for example, inside a motor vehicle door. The adjustment movement provided by the electric drive unit is transmitted via a cover that rotates with the ring gear to a cable, in particular a Bowden cable, that is detachably coupled to the cover.

[0016] In this case, the desired element in or on the motor vehicle can be moved by means of a cable or Bowden cable. This element can be, without limitation, a locking bolt of a locking mechanism, thereby securing the auxiliary actuator. However, in principle, any other adjustment motion can also be achieved by means of the electric drive unit according to the invention, such as the aforementioned mirror adjustment, seat adjustment, window movement, etc.

[0017] To achieve and implement this in detail, the profile of the ring gear is usually annular in shape to support the free shaft, in particular of the gear. Furthermore, a design is often used in which the profile and the ring gear are arranged concentrically with respect to a common axis. Similarly, the pot-shaped cover is usually arranged concentrically with respect to this common axis and is connected to the ring gear in a rotationally fixed manner.

[0018] Furthermore, it is advantageous to adopt a design in which the profile is arranged inside the ring gear, spaced apart from the toothed ring / crown of the ring gear. In particular, a gear engaged in the ring gear and having a guide pin defining the axis ensures that the relevant guide pin slides rotationally along the profile of the ring gear. In this case, a design is also adopted in which the guide pin overlaps the gear at the head side. This allows the guide pin, typically arranged in the center of the toothed ring of a gear, to overlap the toothed ring of a gear engaged in the ring gear. Therefore, it is particularly advantageous to adopt a design in which the profile at least partially overlaps the relevant toothed ring of the gear.

[0019] This means that the guide pin, which defines the axis of the gear engaged in the ring gear, projects with its head-side end beyond the toothed ring of the gear. This allows the head-side end of the guide pin to interact with the profile of the ring gear and, in particular, to slide rotationally along the profile in question during rotational movement of the gear engaged in the ring gear. Advantageously, a design is also employed in which, due to the protruding nature of the free end of the guide pin, the profile at least partially overlaps and can overlap the toothed ring of the gear engaged in the ring gear. This provides additional axial fixation for the guide pin and the gear connected thereto that is engaged in the ring gear. Consequently, during rotational movement along the internal toothing of the ring gear, the toothed ring of the gear moves along the ring gear approximately "under" the profile that at least partially overlaps the toothed ring.

[0020] A cost-effective and weight-optimized embodiment is also characterized by a design in which the shaped part and the ring gear are made of the same material. This also applies to a pot-shaped cover. Overall, a one-piece embodiment in which the cover, the ring gear, and the shaped part are made of plastic has proven particularly advantageous. The gear engaged in the ring gear and the other gear of the transmission connected downstream of the motor can also each be made of plastic.

[0021] The individual spur gears of the intermeshing gears of the transmission can engage with each other using spur or helical toothing. Various combinations are also conceivable. A common design is one in which the transmission comprises two spur gear stages. The first stage, which transmits the rotational motion of the worm on the output shaft of the motor, is equipped with helical toothing to suppress any noise originating from the motor and minimize operating noise, while the second stage connected thereto is equipped with spur toothing. The subsequent stage is the end-side or final stage of the transmission and is equipped with a ring gear and a drive gear engaged therewith.

[0022] Overall, this allows for the provision and implementation of particularly high total transmission or reduction ratios, with values exceeding 100:1, in particular even exceeding 300:1. This allows for the use of a compact and particularly cost-effective electric motor, which itself, in conjunction with the closing auxiliary actuator, provides the force required for the closing function. This allows, for example, the use of conventional electric motors as the electric motor, such as those previously and typically used within motor vehicle locks for the (central) locking function there.

[0023] Thus, an electric drive unit for a motor vehicle, in particular a closing assist actuator, is provided that has a compact and cost-effective design while nevertheless providing a high torque on the output side, with which the force required for the closing function can be generated. This is ultimately achieved in conjunction with the final transmission stage by the combination of a ring gear with a drive gear engaged therewith, wherein a profile on the ring gear additionally ensures that the shaft of the gear is supported on the associated profile on the ring gear. This applies in particular to the free end of the shaft of the gear or to the component of the guide pin that engages the ring gear of the gear at the head end. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be described in detail below with reference to the accompanying drawings which illustrate only one embodiment; in which:

[0025] Figure 1 A perspective view of an electric drive unit according to the invention with a partially opened housing is shown.

[0026] Figure 2 A partial view of the area of the motor and the transmission according to Figure 1 object,

[0027] Figure 3 Show Figure 2 The details in FIG. 1 include the ring gear provided according to the invention together with the annular profile provided thereon. DETAILED DESCRIPTION

[0028] The accompanying drawings show an electric drive unit for a motor vehicle. Figure 1The drive unit shown in the overall overview can, for example, load a motor vehicle lock 1, which is only schematically outlined here and is arranged remotely from the electric drive unit. The motor vehicle lock 1 is equipped with a locking mechanism (not shown) in its interior, which can be locked by means of a locking mechanism according to Figure 1 The electric drive unit is used to close the locking mechanism. To this end, the locking mechanism is first moved into a pre-locking position and then closed by means of the electric drive unit shown. For this purpose, the drive unit acts, by way of example and not limitation, on a locking bolt as part of the locking mechanism inside the motor vehicle lock 1. This is described in detail in DE 10 2013 108 156 A1, which is cited as a reference.

[0029] according to Figure 1 The electric drive unit is generally equipped with an enclosing housing 2, which has or can have a housing lower shell (shown here) and a housing upper shell that closes it. This allows the drive unit to be installed modularly and at virtually any location, for example, inside a motor vehicle door. Within the scope of the exemplary embodiment, a cable 3, designed or capable of being designed as a Bowden cable, ensures the mechanical connection between the drive unit and the motor vehicle lock 1. The cable 3 can be used to transmit a linear adjustment motion to the motor vehicle lock 1, similar to the previously mentioned prior art according to DE 10 2013 108 156 A1, by means of which the bolt of the locking mechanism is transferred from a pre-locking position to a main locking position.

[0030] This is, of course, merely exemplary and in no way restrictive. This means that, in addition to the illustrated embodiment of the electric drive unit as a closing auxiliary actuator, other adjustment movements can of course also be performed with the corresponding drive unit. For this purpose, the drive unit is equipped with an adjustment element 4, which, according to the exemplary embodiment and not by way of limitation, is a cover 4. Figure 1 It can be seen that the cable 3 enters the recess of the adjusting element 4 or the cover 4 with the end of its cable. Figure 1 The rotational movement schematically depicted in FIG. 1 causes the cable of the pull cable 3 to act, for example in a tensile manner, on a locking bolt inside the motor vehicle lock 1 and transfer the locking bolt from the pre-locking position into the main locking position.

[0031] In order to implement and realize this in detail, Figure 1 The drive unit shown in the figure is equipped with an electric motor 5. Drives 6, 7, 8, 9, 10 are connected downstream of the motor 5. For this purpose, the motor 5 acts via a worm 8 arranged on its output shaft on an intermediate gear 9, which is designed as a double gear 9 in this embodiment and meshes with the first transmission stage 6. The first transmission stage 6 is also designed as a double gear and has a gear 10 that engages in the ring gear 7.

[0032] It can be seen that the gears 6, 7, 9, 10 are generally designed as spur gears, and therefore the transmissions 6, 7, 8, 9, 10 are designed as spur gear transmissions. The ring gear 7, which is arranged in the area of the end-side or last second transmission stage 7, is now connected in a rotationally fixed manner to the cover part 4 as the adjustment element 4 already mentioned. As a result, the rotational movement of the ring gear 7 directly leads to the cover part 4 being loaded in this way, for example, Figure 1 , so that the cable 3 is loaded with force in a tensioned manner by means of the cover or adjusting element 4 as described.

[0033] It can be seen that the worm 8, the intermediate gear 9 and the first transmission stage 6 each have a helical toothing. This provides a noise-optimized progression of the transmissions 6 to 10. In contrast, the second transmission stage 7, which is the last on the output side, is equipped with a spur toothing. Furthermore, in this case, the following design is adopted, namely that the spur gear transmission stage or the last transmission stage 7 is equipped with a ring gear 7 and a gear 10 which engages in the ring gear 7 and rotates around the axis. This already provides a compact design, since the gear 10 does not mesh with the teeth of the ring gear 7 on the outside, for example. Furthermore, the ring gear 7 can thus be arranged and placed overlapping with the first transmission stage 6 or the duplex gear 6 implemented here. Furthermore, this also results in a configuration which can be adapted according to Figure 1 A particularly compact structure is shown. Here, a cover part or adjusting element 4 is connected to the ring gear 7, which is designed as a disk or pot within the scope of the exemplary embodiment and has dimensions corresponding to those of the ring gear 7.

[0034] In this way, the size of the housing 2 for receiving the electric drive unit according to the present invention is ultimately determined and predetermined solely by the outer dimensions of the motor 5, the intermediate gear 9, and ultimately the ring gear 7. This results in the already described small and compact design. This is supplemented by the fact that the rotational movement of the output shaft of the motor 5, or its output-side worm 8, can be reduced by the selected transmission design, i.e., taking into account a reduction ratio of greater than 100:1, particularly even greater than 300:1. This allows the assembly of a small, cost-effective, and mass-produced motor 5, as already described.

[0035] Now, according to the present invention, Figure 2 and Figure 3 The diagram in FIG adopts the following design scheme, that is, the shaft of the gear 10 is generally supported on the shaped part 11 of the ring gear 7, which is shown in FIG for the sake of clarity. Figure 2 Omitted from the diagram, however Figure 3This means that the ring gear 7 is additionally provided with the shaped portion 11 in the intermediate region between the outer peripheral teeth and the central region 12 defining the shaft of the ring gear 7. The shaped portion 11 serves to support the shaft of the gear 10 engaged in the ring gear 7.

[0036] In fact, for this purpose, the gear 10 is equipped with a Figure 3 , and which engages on the head side of the toothed ring of the gear 10. The guide pin 13 defines not only the axis of the gear 10 engaged in the toothed ring 7, but also the axis of the gear 6 cooperating with the gear 10, or serves as a through-guide pin 13 for the duplex gears 6, 10 implemented here.

[0037] The guide pin 13 in question can be supported on the bottom side on the housing body or on the Figure 1 13. The lower housing body is shown in FIG. The shaft of the gear 10, which engages in the ring gear 7, and thus the upper end of the guide pin 13, is, by contrast, free. In order to achieve and implement a sound guidance of the shaft of the gear 10 and thus the guide pin 13, a profile 11 is provided on the ring gear 7. The profile 11 ensures axial and radial support of the shaft of the gear 10 and thus the guide pin 13.

[0038] As can be seen, the shaped portion 11 is annular in shape. In practice, the shaped portion 11 and the ring gear 7 are each arranged concentrically relative to a common axis, which extends centrally through a central region 12 or central element of the ring gear 7. Furthermore, the shaped portion 11 in question is arranged within the ring gear 7 at a distance from the toothed ring of the ring gear 7.

[0039] The gear 10 engaged in the ring gear 7 is guided by a guide pin 13, which slides in a rotational manner along the corresponding shaped portion 11. This provides radial support for the guide pin 13. In addition, a design is adopted in which the guide pin 13 overlaps the corresponding gear 10, or the toothed ring formed here, on the head side. In this case, the guide pin 13 is arranged in the center of the previously described toothed ring of the gear 10. This provides additional axial support for the corresponding gear 10.

[0040] observe Figure 3 It is clearly visible that the profile 11 of the ring gear 7 at least partially overlaps the respective toothed ring of the gear 10. This is due to the fact that the guide pin 13 not only overlaps the respective toothed ring at the head end but also has a diameter relative to which the individual teeth of the toothed ring of the gear 10 protrude. As a result, the profile 11 can each overlap at least two teeth of the respective toothed ring of the gear 10 engaged in the ring gear 7. This provides additional axial fixation of the respective gear 10.

[0041] This means that the profile 11 of the ring gear 7 not only ensures that the gear 10 engaged in the ring gear 7 is guided or radially supported along the profile 11, but also ensures that the guide pin 13 or the associated gear 10 is axially fixed, on the one hand via a supporting point (not shown) in the lower housing body of the housing 2 and on the other hand via the individual teeth supported in the relevant axial direction on the lower side of the profile 11.

[0042] For reasons of simple and cost-effective production, the molded part 11 and the ring gear 7 are usually made of the same material, for example plastic. The same applies to the other gears of the transmission 6, 7, 8, 9, 10. Of course, the housing 2 can, if necessary, surround the illustrated electric drive unit in a medium-tight manner, for which purpose a lower housing body shown here can be used, which is inserted into the housing 2. Figure 1 The seal (not shown) in the groove 14 shown in FIG. As a result, the entire electric drive unit can be installed as a modular closing assistance actuator, for example, in a so-called wet chamber inside a motor vehicle door. In this case, the cable 3 is introduced into the housing 2 in question via a sealing sleeve 15 to ensure a media-tight design. According to the present invention, this modular feature is combined with a high reduction ratio, a compact design, and a particularly cost-effective embodiment, which, in summary, provides the main advantages.

[0043] List of reference numerals:

[0044] Motor vehicle lock 1

[0045] Shell 2

[0046] Cable 3

[0047] Cover 4

[0048] Regulatory element 4

[0049] Motor 5

[0050] Transmission mechanisms 6, 7, 8, 9, 10

[0051] Transmission stage 6

[0052] Transmission stage 7

[0053] Ring gear 7

[0054] Worm 8

[0055] Intermediate gear 9

[0056] Double gear 9

[0057] Gear 10

[0058] Molding section 11

[0059] Central Area 12

[0060] Guide pin 13

[0061] Slot 14

[0062] Sealing sleeve 15

Claims

1. An electric drive unit for a motor vehicle, in particular a closing assist actuator, comprising: An electric motor (5); a transmission (6, 7, 8, 9, 10) connected downstream of the electric motor (5); an adjusting element (4) downstream of the transmission (6, 7, 8, 9, 10), wherein the transmission (6, 7, 8, 9, 10) has at least one spur gear transmission stage (7, 10), the at least one spur gear transmission stage comprising a ring gear (7) and a gear (10) engaged in the ring gear (7) and rotating about an axis, It is characterized in that The shaft of the gear (10) is supported on a profile (11) of the ring gear (7).

2. The drive unit according to claim 1, wherein: The shaped portion (11) is annular in shape.

3. The drive unit according to claim 1 or 2, characterized in that: The shaped part (11) and the toothed ring (7) are arranged concentrically with respect to a common axis.

4. The drive unit according to any one of claims 1 to 3, characterized in that The shaped portion (11) is arranged inside the ring gear (7) at a distance from the toothed ring of the ring gear (7).

5. The drive unit according to any one of claims 1 to 4, characterized in that The guide pin (13) of the gear (10) engaged in the ring gear (7) slides along the profile (11) in a rotational manner.

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

7. The drive unit according to claim 5 or 6, characterized in that: The guide pin (13) is arranged in the center of the toothed ring of the gear (10).

8. The drive unit according to claim 7, characterized in that The profile (11) of the toothed ring (7) at least partially overlaps the toothed ring of the gear (10).

9. The drive unit according to any one of claims 1 to 8, characterized in that The shaped part (11) and the ring gear (7) are made of the same material.

10. The drive unit according to any one of claims 1 to 9, characterized in that The adjusting element (4) is designed as a cover part (4) which is connected to the ring gear (2) in a rotationally fixed manner and is preferably hood-shaped or pot-shaped.

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