Actuators for automotive applications

Abstract

To provide an actuator for automotive applications that is compact and achieves a high transmission ratio. The invention comprises an electric motor (1) and an actuating element (5) on which the electric motor (1) acts directly or indirectly via a powertrain (2, 3, 4). The powertrain (2, 3, 4) is provided with at least one evoloid meshing portion (2, 3). According to the invention, the drive shaft (1') of the electric motor (1) is provided with an evoloid pinion (2) which meshes with an evoloid output gear (3) at the input of the powertrain (2, 3, 4), thereby directly forming the evoloid meshing portion (2, 3).

Description

[Technical field]

[0001] The present invention relates to an actuator for automotive applications, in particular an actuator for a locking device of a motor vehicle, which comprises an electric motor and an actuating element which is indirectly or directly acted upon by the electric motor via a power train, and which has at least one evoloid meshing in the power train. [Background technology]

[0002] Actuators for automotive applications are used, for example, to adjust exterior mirrors, check seat adjustment, perform headlamp adjustment or set or adjust windscreen wipers. Furthermore, in principle flap elements, for example of tailgates, trunk lids, car doors, engine hoods, etc., could be acted upon by such actuators.

[0003] In addition to the general automotive application of these actuators, they are also used and implemented in connection with vehicle closing devices, for example closing drives for vehicle doors or tailgates. Furthermore, so-called servo latch holders can also be moved by such actuators in order to close the vehicle door. Furthermore, applications within vehicle door latches are conceivable, for example, so that individual latch members act on, for example, locking members or central locking members. Furthermore, inter alia, in the case of electric vehicles, the fuel filler flap or the charging socket can also be locked by the actuator.

[0004] All fields of application known in the art for such actuators often require a compact design of the actuator due to the limited installation conditions. Thus, in the general specification DE 102010003044 a multi-speed transmission for adjusting a component of a motor vehicle is described. The component may be a seat adjuster, an exterior mirror adjuster or a headlamp adjuster, but also in principle a window controller or other element in or on a motor vehicle. The known multi-speed transmission operates with a first gear stage consisting of a worm and a spur gear or a worm gear meshing with the worm. Furthermore, a second gear stage is implemented.

[0005] The second gear stage is composed of an evoloid pinion and an output gear meshing with the evoloid pinion. A spur gear or a worm gear engaging the worm is connected to the evoloid pinion. The evoloid pinion may be a plastic pinion. In this way, a compact transmission is provided, which is also capable of transmitting high torques.

[0006] Further prior art according to WO 2013 / 045104 describes a spindle drive for motorized adjustment of an adjustment element of a motor vehicle. In this connection, a planetary gear transmission with a rotatable sun gear and, coaxially therewith, a rotatable planetary gear support are also implemented. The engagement between the sun gear and at least one planetary gear of the planetary gear support is configured as an evoroid meshing. In this way, the overall required installation space has to be reduced in the direction of the longitudinal axis of the drive.

[0007] Finally, the prior art according to EP 1 363 809, which is also relevant, concerns an actuator for adjusting the exterior mirrors of a motor vehicle. For this purpose, a mirror adjustment member is implemented which is connected to an electric motor via a power train. The power train has a main gear which is provided in the power train near the mirror adjustment member. The main gear is connected to an evoroid meshing via a pinion.

[0008] As a result, the prior art shows very common actuators for automotive applications that provide at least one evoloid meshing to the powertrain. In this context, the evoloid meshing is generally mounted in the center of the powertrain or adjacent to an actuating element in order to provide a higher transmission ratio at the output of the powertrain by means of such evoloid meshing. Meanwhile, in the prior art, the powertrain at its input usually operates with a worm gear. This is where the present invention originates. Summary of the Invention [Problem to be solved by the invention]

[0009] The technical problem underlying the present invention is to provide an actuator for automotive applications in which a more compact design is achieved compared to the prior art and in which a particularly high transmission ratio is provided with only a single gear stage. [Means for solving the problem]

[0010] In order to solve this technical problem, in the context of the present invention, a generic actuator for automotive applications is characterized in that the drive shaft of the electric motor is provided with an evoloid pinion which meshes with an evoloid output gear, creating an evoloid meshing directly at the input of the powertrain.

[0011] In the context of the present invention, a design can be selected and implemented in such a way that the electric motor, by means of its drive shaft, directly meshes with an evoloid output gear, part of which acts on the actuating element, via an evoloid pinion arranged thereon. In other words, according to the present invention, a single-stage transmission design can be implemented using an evoloid meshing. For this purpose, an evoloid meshing is provided at the input of the powertrain. At the output of the powertrain, the powertrain acts on the actuating element, which performs the required actuating movements. These actuating movements can be both rotational and translational actuating movements and, in principle, a combination thereof.

[0012] Furthermore, it is within the scope of the present invention that in addition to the evoloid meshing at its input, the powertrain also has or can have an auxiliary transmission. The auxiliary transmission can be provided with one or more further evoloid meshings. The auxiliary transmission can also have gear stages with spur gear meshings or helical gear meshings in addition to or instead of the evoloid meshings.

[0013] In this way, a particularly compact embodiment of the actuator according to the invention is generally provided. Depending on the evoroid gearing used, one or more gear stages can be omitted. As a result, the actuator according to the invention furthermore has or can have small dimensions. Furthermore, as a result, the total weight of the actuator can be reduced.

[0014] Moreover, such evoloid meshings have a better effect on the transmission of drive force from the drive shaft to the evoloid output gear than linear meshings. Moreover, evoloid meshings operate quieter than spur gears with linear meshings and have better acoustic properties, which also have a significant impact on the noise level. In stark contrast, such evoloid meshings are usually not designed to be self-locking, so that they can be manually moved and, in particular, manually reset if necessary.

[0015] This is necessary and desirable in particular when the actuator fails and the actuating element acts on it to perform or has to perform the required actuation movement manually in the exemplary case. In the case of such a manually actuated movement, the actuator and therefore the electric motor including the power train must also be moved together, so that any instances of self-locking that are not allowed by the present invention play a special role.

[0016] The evoloid pinion preferably has three teeth. However, in principle, a different number of teeth is also possible, for example only two or only one single tooth or four or six teeth. Furthermore, the so-called normal modulus of elasticity of evoloid pinions is greater than or equal to 0.5. The modulus of elasticity of a gear should generally be understood to be a measure of the size of the teeth. The modulus of elasticity usually clearly indicates the ratio between the diameter of the associated gear and the number of teeth. In the case of evoloid pinions, the normal modulus of elasticity is defined as the modulus of elasticity of the normal section, i.e. the area perpendicular to the flank line of the meshing. Here, the invention makes use of a relatively small normal modulus of elasticity of at least 0.5. As a result, high torques are transmitted and no excessively large force peaks are observed in evoloid pinions, so that plastics can be practically implemented in this respect.

[0017] In other words, the powertrain can be at least partially made of plastic gears. The same applies to the transmission, which is optionally equipped with the powertrain. The evoloid pinion is preferably designed as a plastic pinion. In this connection, and also in other respects, it is generally proven whether the associated evoloid pinion is formed on the spigot. As a result, the spigot with evoloid pinion can be attached to the drive shaft of the electric motor. As a result, the assembly is particularly simple. In this case, the spigot with evoloid pinion can be releasably or even non-releasably connected to the associated drive shaft of the electric motor. Furthermore, the plastic pinion or plastic gear runs much smoother than in the case of a pinion or gear of the same dimensions made of metal.

[0018] As usual, the evoroid meshing is generally referred to as an oblique involute meshing with a very large pitch angle of at least 30°. The evoroid meshing or oblique involute meshing serves to generate large transmission ratios in stages, the axes of the associated gears being added parallel to it. In this way, according to the invention, the drive shaft of the electric motor can be oriented to run parallel to the drive shaft of the actuating element. Furthermore, as a result, the reduction of the gear stages is minimized. In principle, the invention actually works with one single gear stage, i.e. the evoroid meshing, but the powertrain can still be equipped with an auxiliary transmission, as described.

[0019] The actuators according to the invention described herein can be used in all the aforementioned automotive applications. However, in particular the embodiments relating to automotive closing devices are preferably implemented. These can include closing drives, opening drives, servo latch holders, etc. Furthermore, the described actuators can effect the locking of flaps, for example the locking of a fuel filler flap, or the locking of a charging socket in the case of electric or hybrid vehicles.

[0020] The invention will now be explained in more detail with reference to the drawings which show two exemplary embodiments. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram of a first exemplary embodiment of an actuator according to the present invention; [Diagram 2] FIG. 13 is a perspective view of the mounted evoloid meshing portion. [Diagram 3] FIG. 1 shows a first exemplary embodiment of an actuator according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The figures show an actuator for automotive applications, in particular in connection with and for vehicle closing devices, as previously explained in detail. For this purpose, the basic design of the actuator comprises an electric motor 1 and an actuating element 5.

[0023] With reference to the exemplary embodiment according to Fig. 1, it can be seen that the motor vehicle has an electric motor 1 and an actuating element 5 acting indirectly or directly via a powertrain 2, 3, 4. The exemplary embodiment according to Fig. 1 shows an actuator designed as a microdrive. In the exemplary embodiment, the powertrain 2, 3, 4 is provided with only one evoroid meshing 2, 3 for transmitting the rotational movement of the drive shaft 1' of the electric motor 1, so that the actuating element 5 is actuated directly by the powertrain 2, 3, 4.

[0024] In this case, an evoloid meshing 2, 3 is provided between the evoloid pinion 2 and the evoloid output gear 3. A threaded spindle 4 is rotatably and fixedly connected to the evoloid output gear 3. In the context of the variant according to FIG. 1, a spindle nut which is integrated into the actuating element 5 or which constitutes a component of the actuating element 5 is received in the threaded spindle 4. In this way, the rotation of the threaded spindle 4 enables the actuating element 5 to perform a linear movement or a translational movement in the direction of the double arrow shown in FIG. 1.

[0025] It will be appreciated that the drive shaft 1' at the output of the electric motor 1 is provided with an evoloid pinion 2. For this purpose, the evoloid pinion 2 is designed as a spigot. The spigot or evoloid pinion 2 is fitted as a whole to the drive shaft 1' of the electric motor 1 and has a hollow hole for this purpose. Furthermore, the spigot 2 may furthermore be fixed to the drive shaft 1' of the electric motor 1.

[0026] It will be appreciated that the evoloid meshing 2, 3 with the evoloid pinion 2 and the evoloid output gear 3 have in each case rotation axes that extend parallel to one another. In this way, a particularly compact design is provided. The rotation axes are oriented with a spacing A relative to one another. Furthermore, as a consequence, the design may be such that the drive shaft 1' of the electric motor 1 and the actuating element 5 as a whole also extend parallel to one another. This is because the actuating element 5 or the spindle nut moves in its longitudinal direction along the axis of rotation of the threaded spindle 4, which coincides with the axis of rotation of the evoloid output gear 3. The same spacing A can therefore be found between the actuating element 5 or its longitudinal axis and the drive shaft 1' of the element 1.

[0027] A detail of the evoloid meshing 2, 3 is shown in FIG. 2. It will be recognized that the evoloid pinion 2 in the exemplary embodiment is provided with a total of four teeth. In general, it is also possible to operate with a reduced number of teeth of the evoloid pinion 2. In the exemplary embodiment shown, the evoloid pinion 2 has three teeth. Moreover, the design in the exemplary case is such that the individual teeth of the evoloid pinion 2 have a normal modulus of elasticity of at least 0.4. On the other hand, the helical toothed evoloid output gear 3 according to the exemplary embodiment has a total of 40 teeth. The modulus of elasticity or normal modulus of elasticity of the evoloid output gear 3 is likewise at least 0.4. Due to the stated number of teeth of the evoloid pinion 2 on the one hand and the evoloid output gear 3 on the other hand, in the exemplary embodiment, the transmission ratio of the evoloid meshing 2, 3 thus obtained is now 10.0 or 1 to 10, as shown in FIG. 3.

[0028] In other words, one revolution of the evoloid output gear 3 corresponds to ten revolutions of the evoloid pinion 2. In general, other transmission ratios can be implemented at this point. The evoloid meshing parts 2, 3 usually have a transmission ratio of at least 5.0, preferably 10.0 or more.

[0029] In the exemplary embodiment according to Fig. 1, the rotation of the output shaft of the electric motor 1 is directly transmitted to the actuating element 5 via an evoloid output gear 3 which is rotatably fixedly connected to a threaded spindle 4. In an alternative design, one or more intermediate shafts can be provided, which are designed as evoloid gear stages or, conventionally, also as spur gear stages, between the evoloid output gear 3 and the threaded spindle 4.

[0030] The second exemplary embodiment according to Fig. 3 makes it clear that the power train 2, 3, 4 corresponding to the variant according to Fig. 1 can be provided at its input with an additional transmission 6, 7; 8, 9 in addition to the evoroid meshing 2, 3. The transmission 6, 7; 8, 9 is composed of a first gear stage 6, 7 and a second gear stage 8, 9. Fig. 3 shows an actuator designed as a charging socket actuator, which is provided for locking the charging socket of an electric vehicle.

[0031] In the first gear stage 6, 7, an evoloid pinion 6 is again used, which meshes with an obliquely toothed evoloid output gear 7. At this point, a transmission ratio of 3.6 or 1 to 3.6 is observed, as shown in FIG. 3. The evoloid pinion 6 of the first gear stage 6, 7 is connected so as to be rotatably fixed to the evoloid output gear 3 of the evoloid meshing section 2, 3 at the input of the power train 2, 3, 4 or 2, 3.

[0032] The input gear 8 of the second gear stage 8, 9, which partially meshes with the evoloid output gear 9 of the second gear stage 8, 9, is connected to the evoloid output gear 7 of the first gear stage 6, 7 so as to be rotatably fixed. The two gears 8, 9 of the second gear stage 8, 9 are designed as straight-toothed spur gears. On the other hand, the spur gears 2, 3 of the evoloid meshing section 2, 3, like the spur gears 6, 7 of the first gear stage 6, 7, have in each case the already described evoloid pinion 2 or 6 at the input end and the obliquely toothed evoloid output gear 3 or 7 at the discharge end. In an alternative configuration, both the first gear stage 6, 7 and the second gear stage 8, 9 can be configured as evoloid gear stages or as spur gear stages.

[0033] According to the exemplary embodiment according to FIG. 3, the evoloid meshing 2, 3 at the input of the powertrain 2, 3, 4 or 2, 3 together with the downstream connected transmission 6, 7; 8, 9 results in an overall transmission ratio of about 86.4 or 1 to 86.4 (10×3.6×2.4), so that it is possible to realize a substantial transmission ratio in a simultaneously compact design. Furthermore, there is the possibility to design the powertrain 2, 3, 4 or 2, 3 at least partially with plastic gears, as well as the transmission 6, 7; 8, 9. According to the exemplary embodiment, at least the evoloid pinion 2 and the evoloid output gear 3 are manufactured from plastic. The further gears 6, 7; 8, 9 of the downstream connected optional transmission 6, 7; 8, 9 can also be manufactured from plastic. Overall, in the variant according to Fig. 3, the actuating element 5 shown therein is acted on indirectly by the electric motor 1 via the power train 2, 3, 4, i.e. through the intervention of the transmissions 6, 7; 8, 9. Furthermore, in this variant, the threaded spindle 4 is omitted, since in this case the actuating element 5 is acted on by an evoloid output gear 9 at the output of the second gear stage 8, 9.

Claims

1. An actuator for a fuel filler flap or a charging socket of a motor vehicle, comprising an electric motor (1) and an actuating element (5) which is indirectly or directly acted upon by said electric motor (1) via a power train (2, 3, 4), the drive shaft (1') of said electric motor (1) is oriented to run parallel to the drive shaft of said actuating element (5); An actuator having at least one evoloid meshing portion on the power train (2, 3, 4), a drive shaft (1') of the electric motor (1) is provided with an evoloid pinion (2) which meshes with an evoloid output gear (3) having rotation axes which extend parallel to each other at the input of the power train (2, 3, 4), thereby directly forming the evoloid meshing portion (2, 3), and the direct meshing of the evoloid meshing portion of the evoloid pinion (2) with the evoloid meshing portion of the evoloid output gear (3) forms a single gear stage; The power train (2, 3, 4) comprises a threaded spindle (4) receiving an actuating element (5) which is a spindle nut, the threaded spindle (4) being rotatably and fixedly connected to the evoloid output gear (3); The spindle nut moves longitudinally along the axis of rotation of the threaded spindle (4) which coincides with the axis of rotation of the Evoroid output gear (3); An actuator, wherein a distance (A) between the rotation axes of the evoloid pinion (2) and the evoloid output gear (3) is the same as a distance between the rotation axes of a drive shaft (1') and an actuating element (5), and the electric motor (1), the drive shaft (1') and the actuating element (5) are arranged on the same side of the rotation plane of the evoloid output gear (3).

2. 2. An actuator according to claim 1, characterized in that the evoloid pinion (2) is formed on a spigot.

3. 3. An actuator according to claim 2, characterized in that the spigot or evoloid pinion (2) is fitted as a whole on the drive shaft (1') of the electric motor (1).

4. The actuator according to any one of claims 1 to 3, characterized in that the transmission ratio of the evoloid meshing portion (2, 3) is at least 5.0 or more.

5. An actuator according to any one of the preceding claims, characterized in that the evoloid pinion (2) has three teeth.

6. An actuator according to any one of the preceding claims, characterized in that the drive shaft (1') of the electric motor (1) and the actuating element extend parallel to each other.

7. 7. An actuator according to claim 1, characterized in that the power train (2, 3, 4) has at its input, in addition to the evoloid meshing (2, 3), an auxiliary transmission (6, 7; 8, 9) which comprises one or more further evoloid meshings (6, 7).

8. An actuator according to any one of the preceding claims, characterised in that the power train (2, 3, 4) and / or the transmission (6, 7; 8, 9) consist at least partly of plastic gears.

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