Actuators for Automotive Applications

Abstract

The present invention relates to an actuator (1) for motor vehicle applications, in particular for a vehicle locking device, comprising an electric motor (3), an actuating element (5) which can be acted on directly or indirectly via a drive train (4), and a drive wheel (9) with evoloid teeth arranged on the drive shaft (8) of the electric motor (3), the drive train (4) having at least one crown gear stage (12).

Description

[Technical field]

[0001] The present invention relates to an actuator for automotive applications, in particular for vehicle locking devices, comprising an electric motor, an actuating element which can act directly or indirectly via a drive train, and a drive wheel arranged on the output shaft of the electric motor and having an evoroid toothing.

[0002] Actuators for automotive applications are used, for example, for adjusting exterior mirrors, adjusting seats, adjusting headlights, or setting or adjusting windshield wipers. In addition, hinge elements such as tailgates, trunk lids, car doors, engine hoods, etc. are also actuated with the aid of such actuators.

[0003] In addition to these general automotive applications for actuators, these actuators are also used and practiced in connection with vehicle closure devices, for example the closing drives of vehicle doors or tailgates. Furthermore, so-called cinching latch strikers can also be moved with such actuators in order to close the vehicle door. Furthermore, applications in vehicle door latches are conceivable, for example, in which individual latch elements (for example locking elements or central locking elements) are acted upon. Furthermore, the actuators can also be used to lock fuel filler caps or charging sockets in electric vehicles.

[0004] All practically known fields of application for such actuators often require a compact design of the actuator due to the small installation space. For this reason, within the scope of the general DE 10 2010 003 044 A1, a multi-stage transmission for adjusting a structural unit of a motor vehicle is described. The structural unit can be a seat adjuster, an exterior mirror adjuster or a headlight adjuster, and in principle a window control or other element in or on a motor vehicle. The known multi-stage transmission operates with a first gear stage consisting of a worm and a spur gear or worm wheel meshing with the worm. A second gear stage is also implemented.

[0005] The second gear stage consists of an evoloid pinion and an output wheel that meshes with it. A spur gear or a worm wheel that engages with the worm is connected to the evoloid pinion. The evoloid pinion may be a plastic pinion. In this way, a compact transmission device that is also capable of transmitting high torques is obtained.

[0006] In the further state of the art according to WO 2013 / 045104 A1, a spindle drive for motorized adjustment of an adjustment element of a motor vehicle is described. In this connection, a planetary gear arrangement is also realized with a rotatable sun gear and a coaxially rotatable planetary gear carrier. The engagement between at least one planet gear of the planetary gear carrier and the sun gear is designed as an evoroid tooth profile. In this way, the installation space required in the longitudinal direction of the drive is reduced overall.

[0007] Finally, the state of the art according to EP 1 363 809 B1 relates to an actuator for adjusting the exterior mirrors of a motor vehicle. For this purpose, a mirror adjustment element is implemented which is coupled to an electric motor via a drive train. The drive train has a main gear arranged in the drive train in the vicinity of the mirror adjustment element. The main gear is connected to a pinion with evoroid teeth.

[0008] DE 102017125819 A1 discloses an actuator for a motor vehicle, in which an electric motor acts on a drive train, which in turn moves an actuating element, and an evoroid pinion forming a spur gear stage with the output wheel of a first gear stage is arranged in the drive train, preferably on the drive shaft of the electric motor.

[0009] Thus, the state of the art very generally shows actuators for automotive applications that provide at least one evoloid tooth profile in their drive train. In this context, the evoloid tooth profile is implemented in the center of the drive train or adjacent to the actuating element, in order to generally provide a high transmission ratio at the output of the drive train with the help of such evoloid tooth profile. In contrast, in the state of the art, the drive train usually operates with a worm gear at its input. This is where the present invention begins.

[0010] overview

[0011] The present invention is based on the technical problem of providing such an actuator for automotive applications, as a result of which, compared to the state of the art, an even more compact design is achieved and in particular high transmission ratios are obtained with only a single gear stage.

[0012] Based on the known state of the art, it is an object of the present invention to provide an improved actuator for automotive applications, in particular a compact actuator with a large transmission ratio, high efficiency and resettability.

[0013] This object is achieved by the features of the independent claim 1. Advantageous embodiments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments described below are not limiting. Rather, any option for the modification of the features and drawings described in the description and the dependent claims is possible.

[0014] According to claim 1, the object of the invention is achieved by providing an actuator for motor vehicle applications, in particular for a locking device of a motor vehicle, comprising an electric motor, an actuating element which is acted on directly or indirectly via a drive train, and a drive wheel arranged on the output shaft of the electric motor and having an evoroid tooth profile, the drive train comprising at least one crown gear stage. The configuration of the actuator according to the invention makes it possible to provide a very compact actuator which allows a high transmission ratio in one gear stage while achieving a high efficiency of the gear stage. By using a crown gear stage, a gear stage can be provided which requires a minimum of installation space. In particular, the central axis of the drive wheel can be formed perpendicularly, preferably approximately perpendicularly, to the central axis of the output wheel. As a result, there is the possibility to arrange the output wheel in a longitudinally extending direction of the drive wheel and provide a gear stage which can essentially be limited by the width of the electric drive. The compactness of the transmission device can therefore be advantageously combined with a high transmission ratio and a high efficiency. Furthermore, the crown gear stage provides the possibility of resetting, in other words the crown gear stage is preferably manually resettable. This has the advantage that in the event of a power supply failure, the actuating element can be manually reset.

[0015] The invention is based on the consideration that a crown gear stage is more efficient than a bevel gear stage. During the rotational movement of the crown gear stage, there are no axial forces between the pinion and the crown gear, or only small axial forces in the case of a helical tooth profile. On the other hand, the tooth profile of the crown gear and the pinion used to drive the crown gear can be manufactured relatively easily, and the crown gear is preferably designed as a plastic part. Therefore, the crown gear stage can be manufactured more cheaply than the bevel gear stage. The rolling-optimized design also improves the smooth running of the drive train.

[0016] Furthermore, the invention recognizes that the output shaft of the crown gear stage does not have to absorb any axial forces, or only minimal axial forces compared to the bevel gear stage. In the case of a spur gear pinion, the pinion can also be freely moved axially over the crown gear tooth profile without affecting the contact pattern or backlash. Thus, the use of a crown gear stage allows the gear stage to be constructed axially shorter.

[0017] The actuators described according to the invention can be used in all of the above mentioned automotive applications. However, in particular embodiments related to automotive closing devices are advantageously implemented. This may be a closing drive, an opening drive, a cinch latch striker, etc. Furthermore, flap locks such as fuel filler cap locks or locks on charging sockets in electric or hybrid vehicles can also be implemented with the help of the described actuators.

[0018] In an advantageous embodiment variant, the drive wheel interacts directly with the output wheel designed as a crown gear. The use of a crown gear stage directly adjacent to the motor brings about several advantages. On the one hand, it is possible to machine the drive shaft and the output shaft without an axial distance, and the axial distance at which the axes cross can be 0 mm. Furthermore, a gear stage with a crown gear has the advantage of forming a gear stage that requires very little installation space. For example, the actuator can be designed to be very flat, which means that a flat drive train can be achieved for the entire actuator. A compact design can be achieved in particular by combining no or only a small axial distance between the wheel and the pinion with an overlap between the drive wheel and the crown gear.

[0019] A variant of another embodiment of the invention can also be represented when the axis of the drive wheel and the axis of the output wheel intersect. If the actuator, and in particular the first gear stage of the drive train, is designed in such a way that the pinion of the drive on the output shaft of the motor is directly aligned in the axial direction of the output wheel, a design solution can be provided that requires a minimum of installation space. The drive wheel on the shaft of the motor is designed as an evoroid gear, which allows a positive engagement condition between the drive wheel and the output wheel to be realized. In particular, a gear stage characterized by a very smooth running can be realized. However, the main advantage of the crown gear stage is that a high efficiency can be achieved. Small installation space, smooth running and high efficiency are advantages that can be combined by the arrangement according to the invention in the actuator.

[0020] A further embodiment variant of the invention is obtained if the axes of the drive and output wheels have an axial offset. It is also conceivable according to the invention to set an axial offset between the drive and driven gears. This allows design freedom that allows individual solutions based on the available installation space of the actuator. Especially in automotive applications, the available installation space is always limited. Therefore, design freedom in the design of the gear stages allows maximum design freedom, which has a positive effect on the installation space required for the actuator. With the same performance of the actuator, the dimensions of the actuator can be adapted to the available installation space.

[0021] In another embodiment variant, the drive wheel and the output wheel form a crown gear stage, which forms a first gear stage of the drive train, which drives at least a second gear stage. By driving the further gear stages by the crown gear stage, a high transmission ratio can be achieved in the actuator. The high transmission ratio therefore allows the required actuation force to be provided for the actuating element. In combination with the high-speed electric motor used, high actuation forces and short actuation times for the actuating element can be achieved. Due to the possibility of achieving a high transmission ratio in the gear stages, a motor with a smaller power can be used, which has a positive effect on the cost of the actuator. Furthermore, a low-power and / or small motor, i.e. a motor with small dimensions, makes it possible to further reduce the installation space for the actuator. The advantages of using a crown gear stage add up in terms of installation space, force and actuation speed of the actuating element.

[0022] A further advantageous embodiment variant of the invention is obtained if the second or further gear stage has an evoloid tooth profile. The auxiliary gear can be equipped with one or more further evoloid teeth. Also, the auxiliary gear can have a gear stage with a spur gear tooth profile or a helical tooth profile in addition to or instead of the evoloid tooth profile. In this way, a particularly compact embodiment of the actuator according to the invention is generally available. Due to the evoloid tooth profile used, one or more gear stages can be omitted. This also means that the actuator of the invention has or can have small dimensions. Also, the weight of the actuator as a whole can be reduced. Furthermore, the evoloid tooth profile has a positive effect on the background noise, since it is acoustically better with less operating noise than a spur gear with a straight tooth profile. Needless to say, such evoloid tooth profiles are generally not designed to be self-locking, so that they can be moved manually if necessary and, in particular, reset manually.

[0023] If the gears of the gear stages are designed parallel to one another, this again offers a constructionally advantageous solution: if the axis of the crown gear of the first gear stage is arranged parallel to the second axis of the means of the second gear stage which is driven by the crown gear, the drive train of the actuator can be provided with a minimum installation space.

[0024] A compact design is a notable advantage of the drive train arrangement, in particular the use of at least one crown gear. For example, the actuator can be used to lock the fuel filler cap and / or the charging plug. There is generally little space available in the area of ​​the charging plug, charging socket or fuel filler cap. The installation space can be minimized by using axially parallel gear stages and at the same time the requirements for the actuator, e.g. actuation force, can be met.

[0025] The drive wheel can have one to four teeth, preferably three. The drive wheel or the evoloid pinion preferably has three teeth. In principle, however, a different number of teeth is also possible, for example only two teeth or only one tooth, or only four or six teeth. Also, the so-called normal modulus of the evoloid pinion is greater than or equal to 0.5. The module of a gear is generally understood to be a measure of the size of the teeth. In general, the module clearly describes the relationship between the diameter of the gear in question and the number of teeth. In the case of evoloid pinions, the normal module is defined as the coefficient of the normal part, i.e. the coefficient of the tooth surface perpendicular to the line of the tooth root surface. Here, the invention uses a relatively small normal module of at least 0.5. As a result, high torques can be transmitted, which can also be realized here with plastic, since no excessively large force peaks are observed in evoloid pinions.

[0026] If the gears of the gear stages are at least partially made of plastic, this in turn brings advantages to the invention. This means that the drive train can be constructed at least partially from plastic gears. The same applies to the gearbox that is optionally equipped in the drive train. The evoroid drive wheels and the crown gear as the output wheel are preferably designed to be made of plastic. Parts of the transmission made of plastic are particularly characterized by being cheap to manufacture and lightweight. Furthermore, plastic pinions or plastic gears run much smoother than metal pinions or metal gears of otherwise the same dimensions.

[0027] In a further development of the invention, the actuator has an emergency release. The emergency release can be performed directly manually, for example by being manually gripped and the actuating element being movable. The emergency release can consist of a cable or a pulling element, by which the actuating element can be returned to the retracted position from the position protruding from the actuator. However, it is also conceivable that, for example, a mechanical intervention in the actuating element is necessary, for example, so that the actuating element can be moved, for example, so that a gear stage or gear stages can be reset via the actuating means. An emergency actuation or emergency release is necessary, for example, if the actuating element is in the extended position and there is a power or voltage failure in the motor vehicle. In this case, it should be possible to reset the actuating element so that an emergency release is possible. The emergency release relates, for example, to the use of the actuating element for locking the charging plug.

[0028] The present invention will be described in more detail below based on preferred exemplary embodiments with reference to the accompanying drawings. However, the principle that the exemplary embodiments do not limit the present invention, but are merely advantageous embodiments, is applied. The features shown can be implemented individually or in combination with further features of the specification as well as in the claims, individually or in combination. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 shows a plan view of an actuator designed in accordance with the present invention together with a diagram of the drive train, with only those components essential for explaining the invention reproduced. [Diagram 2] FIG. 2 shows a view of the drive train according to FIG. 1 from a rear view, without the housing shell with the housing cover. Detailed Description of the Invention

[0030] FIG. 1 shows an actuator 1 in a three-dimensional view and in a view of a housing shell 2, which comprises an integrated electric motor 3, a drive train 4, an actuating element 5, an emergency release means 6 and a switch means 7. The actuator 1 can be used, for example, to lock a fuel filler cap or a charging plug of an electric vehicle. In this case, the actuating element 5 serves as a bolt to prevent the fuel filler cap from being opened, for example during charging, or the charging plug from being pulled out. In this respect, FIG. 2 shows the locked state. The actuating element 5 has been moved out of the housing 2 of the actuator 1. The actuating element 5 can be moved out of or into the housing 2 in the direction of the arrow P.

[0031] A drive wheel 9 is arranged on the drive shaft 8 of the electric motor 3, which can be mated with the drive shaft 8, for example. The drive wheel 9 is designed as an evoloid gear 9 and meshes with a crown gear 10. In this exemplary embodiment, the evoloid gear 9 has three teeth. As shown by the dashed-dotted line L, the arrangement between the drive wheel 9 and the crown gear 10 is designed such that there is no axial distance between the drive shaft 8 and the axis 11 of the crown gear 10. In other words, the axis 8 and the axis 11 intersect. The evoloid gear 9 and the crown gear 10 form a crown gear stage 12. It should be noted that the electric motor 3 is matingly accommodated in a receptacle 13 of the housing 2.

[0032] As can be clearly seen in FIG. 2, the crown gear interacts with another gear 14 to form a second gear stage 15. In this exemplary embodiment, the second gear stage is designed as a spur gear stage. The gear 14 is provided with teeth only in certain areas and is further formed in some areas with a peripheral raised portion 16, which can engage with a switch means 7 (in this case a microswitch). The gear wheel 14 thus serves on the one hand to transmit torque to the actuating element and on the other hand to detect the position of the actuating element 5. The position of the actuating element 5 shown in these FIGS. 1 and 2 is the locked position, which corresponds to the release of the switch means 7. In the retracted state of the actuating element 5, the gear 14 or the raised portion 16 is moved such that the raised portion moves into the effective range of the switch means 7, which is actuated. This makes it possible to detect the position in which the actuating element 5 is located. In this exemplary embodiment, the axis 11 of the crown gear and the axis 17 of the second gear 14 are arranged parallel to each other. This makes it possible to achieve a high transmission ratio with a minimum installation space.

[0033] 1 , the gear 14 of the second gear stage 15 interacts directly with the actuating element 5. For this purpose, a further tooth profile 18 is formed on the gear 14 and directly engages with a tooth profile formed as a toothed rack 19 on the actuating means 5. Thus, in this embodiment, the drive wheel 9, the crown gear 10, the gear 14 and the toothed rack 19 form the drive train 4, which is driven via the electric motor 3, which in this respect also forms part of the drive train 4.

[0034] The actuating element 5 is shown in the extended position in Figures 1 and 2. In case of a power failure in the extended position, the operator can move the actuating element 5 back to the released position with the help of the emergency release means 6. For this purpose, for example, a handle part (not shown) can be arranged on the emergency release means 6, which can be grasped and actuated by the operator. Thus, by actuating the emergency release means 6 in the direction of the arrow P1, the actuating element 5 can be moved to the unlocked position.

[0035] 2 shows an alternative and second possibility for moving the actuating element 5. The actuating means 20 is equipped with a gear 21, which meshes with a gear 22 of the second gear stage 15. When the actuating means 20 is moved, for example by a tool, the second gear stage 15 can be moved and, as a result, the actuating element 5 can be moved into the locked or unlocked position. The gear 22 is preferably manufactured in a separate assembly from the gears, although it is also conceivable to form the gear 22 integrally with the gear 14.

[0036] Thus, the actuation means 20 can function as an emergency release means, but locking can also be effected by the actuation means 20.

[0037] Figure 1 shows a part of the housing 2, in particular the housing shell 2, and figure 2 shows a housing cover which closes the housing 2. The actuating element 5, the emergency release means 6 and the operating means 20 can be led out of the housing 2 via sealing means 24, 25, in particular elastic sealing means 24, 25.

[0038] As is clear from the figure, a compact construction of the actuator 1 can be achieved by forming a crown gear stage 12 in combination with the second gear stage 15, the advantage of which is that it allows the construction of the actuator 1 with minimal external dimensions. Furthermore, a high efficiency, for example 0.88, can be achieved, which can be advantageously combined with the very smooth running and transmission of large torques of the crown gear stage. In this exemplary embodiment, the gear stages 12, 15, 19 as well as the housing shell 2, the actuating element 5, the emergency release means 6, the drive wheel 9, the crown gear stages 10, 11, 12, the receptacle 13, the gears 14, 15, 18, 21, 22, the toothed rack 19, the actuating means 20 and the housing cover 23 are made of plastic, which has a positive effect on the smooth running, weight and cost of the actuator 1.

[0039] Explanation of symbols

[0040] 1...Actuator, 2…Housing shell, 3...electric motor, 4...Drive train, 5...operating element, 6...Emergency release means, 7...switch means, 8...Drive shaft, 9...Drive wheel, 10...Crown gear, 11,17…axis, 12...Crown gear stage, 13...Receptacle, 14,18,21,22...Gear, 15…second gear, 16…ascending section, 19…Toothed rack, 20...operating means, 23…Housing cover, 24,25...Sealing means, P, P1...arrow, L…Line.

Claims

1. An actuator (1) for automotive applications, an electric motor (3) having a drive shaft (8); A drive train (4); an actuating element (5) that can be acted on directly or indirectly via the drive train (4) and that is arranged on the drive shaft (8) of the electric motor (3); A drive wheel with evoroid teeth (9); Equipped with The drive train (4) has at least one crown gear stage (12), The drive wheel (9) and the output wheel form the crown gear stage (12); The crown gear (12) is a first gear of the drive train (4), the first gear driving a second gear (15) of the drive train (4) including a gear wheel; The actuator (1), characterized in that the actuating element (5) includes a toothed rack (19), and the gear wheel of the second gear stage (15) has a tooth profile (18) that engages with the toothed rack (19) to move the actuating element (5).

2. 2. An actuator (1) according to claim 1, characterized in that the drive wheel (9) interacts directly with an output wheel designed as a crown gear (10).

3. 3. An actuator (1) according to claim 1 or 2, characterized in that the central axis of the drive wheel (9) and the central axis of the output wheel intersect.

4. 3. The actuator (1) according to claim 1 or 2, characterized in that the axis (8) of the drive wheel (9) and the axis (11) of the output wheel have an axial offset.

5. The actuator (1) according to any one of the preceding claims, characterized in that the second gear stage (15) has an evoroid tooth profile.

6. The actuator (1) according to any one of claims 1 to 5, characterized in that the axis of the output wheel of the first gear stage and the axis of the gear wheel of the second gear stage (15) are designed to be parallel to each other.

7. Actuator (1) according to any one of the preceding claims, characterised in that the drive wheel (9) has 1 to 4, preferably 3, teeth.

8. The actuator (1) according to any one of the preceding claims, characterized in that the gears (9, 10, 14, 18, 21, 22) of the first and second gear stages (15) are at least partially made of plastic.

9. The actuator (1) according to any one of the preceding claims, characterized in that the actuator (1) has an emergency release part (6, 20).

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