WO2023104235A1

WO2023104235A1 - Actuating drive for motor vehicle applications

Info

Publication number: WO2023104235A1
Application number: PCT/DE2022/100847
Authority: WO
Inventors: Michael Berres
Original assignee: Kiekert Aktiengesellschaft
Priority date: 2021-12-08
Filing date: 2022-11-14
Publication date: 2023-06-15
Also published as: DE102021132239A1

Abstract

The invention relates to an actuating drive (7) for motor vehicle applications, in particular for locking devices, comprising an electric motor (2) and a drive train (3, 4) and an actuating element (5, 12) driven by the drive train (3, 4), wherein at least a first and a second gear stage (3, 4) are provided in the drive train (3, 4), and wherein at least one gear stage (3, 4) has a transmission ratio which is variable at least in regions.

Description

Actuator for automotive applications

The invention relates to an actuator for motor vehicle applications, in particular locking devices, having an electric motor and a drive train and an actuating element driven by the drive train, with at least a first and a second gear stage being provided in the drive train.

Actuators are used where, for example, a vehicle part needs to be locked. A fuel filler flap, a cover or a storage compartment can be mentioned here, for example, as well as, for example, a lock for a charging plug of an electric or hybrid vehicle. The actuators are used here to secure the tank flap against unauthorized access, for example when locking a motor vehicle. A charging plug for a hybrid or electric vehicle is usually plugged into a charging socket provided on the vehicle. Since high currents and voltages can sometimes flow during charging, the charging process must be secured. For this purpose, control elements are used that secure the charging plug to the charging socket, for example an actuator being arranged on the charging socket and the control element being connected to the charging plug as a locking pin in such a way that the charging plug cannot be removed from the charging socket during charging. The same applies to a fuel filler flap, in which case an actuating element is arranged in the motor vehicle in such a way that when the motor vehicle is locked, the actuating element can be brought into engagement as a locking pin with the fuel filler flap, so that the fuel filler flap cannot be opened when the vehicle is locked.

In order to meet the requirements of automobile manufacturers, these actuators must be compact, have a high level of functional reliability and also have a low weight. In order to be able to provide a more compact design of an actuator for motor vehicle applications, DE 10 2017 125 819 A1 discloses an actuator with an electric motor and an actuating element that is directly or indirectly acted upon by the electric motor via a drive train, with at least one evoluid toothing in the drive train is realized. This construction generally provides a particularly compact embodiment of an actuator, while at the same time the overall weight of the actuator can be reduced.

Another compact design of an actuator is known from DE 10 2020 101 363 A1. The actuator has an electric motor, an actuating element that can be acted upon directly or indirectly via a drive train, and a drive wheel equipped with evoluid teeth on a drive shaft of the electric motor, the drive train having at least one crown wheel stage. By combining the different gears, a compact actuator can be provided, which at the same time enables high transmission ratios in a gear stage.

The known state of the art has proven itself in principle, but then reaches its limits when operationally different forces have to be made available in the actuator in order to be able to guarantee the functional reliability of the actuator. Functional reliability can be limited, for example, when voltage peaks occur during operation of the actuator due to icing, for example on a charging plug, in which case a locking pin or the actuating element is to be moved from an icy position. This is where the invention comes in.

The invention is based on the technical problem of providing an actuator for motor vehicle applications which, in comparison to the prior art, can deliver a high level of functional reliability in all operating situations. It is therefore the object of the invention to provide an improved actuator for motor vehicle applications. The particular task here is to provide an actuator that ensures functional reliability even in extreme situations.

The object is achieved according to the invention by the features of independent patent claim 1. Advantageous refinements of the invention are specified in the dependent claims. It is pointed out that the exemplary embodiments described below are not restrictive; instead, any possible variations of the features described in the description and the subclaims as well as the figures are possible.

According to patent claim 1, the object of the invention is achieved in that an actuator for motor vehicle applications, in particular for locking devices, is provided, having an electric motor, a drive train and an actuating element driven by means of the drive train, with at least a first and a second gear stage in the drive train is provided and wherein at least one gear stage has an at least partially variable translation. The construction of the actuating drive according to the invention now creates the possibility of being able to provide different forces for moving the actuating element or locking element by means of the drive train. This is particularly advantageous when greater forces have to be made available to move the actuating element due to, for example, icing of the actuating drive. It can happen, for example, that the actuator is used to lock a charging connector in an electric or hybrid vehicle, the charging process having taken place overnight and under extreme weather conditions. It is also not always possible to completely prevent icing of an engagement area of the actuating element. If the locking element or actuating element has to be moved back to its starting position at the end of the charging process, the actuating element must be moved against the icing. It may be necessary to move the actuating element with an increased actuating force in order to break the ice. By using a gear stage with a variable transmission ratio according to the invention, a means can be made available in order to be able to move the actuating element safely into its functional positions even in extreme situations.

As already mentioned in the introduction, actuators are used where actuating or locking elements in the motor vehicle have to be moved. Locks for flaps, covers, locking compartments, cargo compartments, but also locks for charging plugs in electric or hybrid vehicles can be mentioned here. The actuators are distinguished by a particularly compact structure, so that the actuators can be easily placed in the motor vehicle or implemented in other components of the motor vehicle.

Overall, the actuators have at least one electric drive in the form of an electric motor and can therefore be supplied with electric power via the network in the motor vehicle. In addition, electric motors are extremely compact as miniature drives and, in combination with one or two or more gear stages, can achieve fast actuating times in the actuating element.

The electric motor interacts with a drive train, it being possible for a worm wheel, an evoluid gear wheel or an involute-toothed gear wheel to be arranged on the output shaft of the electric motor. The transmission element arranged on the output shaft of the electric motor forms a first transmission stage with the output wheel, which interacts with at least one further transmission stage. Preferably and according to the invention, the second or a further gear stage is equipped with a variable transmission. If a constant torque is made available via the first gear stage, a variable torque for driving the actuating element can be made available by means of the second or further gear stage. Depending on the requirements for the actuating element, the space available for the actuating drive and/or the actuating times required for the actuating element, it can be advantageous for there to be more than two gear stages in the actuating drive. At least one gear stage is equipped at least in some areas with a variable translation. Area-by-area means here that a partially constant torque can be transmitted through the second gear stage, for example, but the transmission ratio in the gear stage changes at least in a partial area of the gear stage. A different torque or a different force can thus be made available for moving the actuating element.

If the second gear stage drives the actuating element directly, then an advantageous embodiment of the actuating drive is made available. The structure of a drive train from a first and a second gear stage represents a compact structure of an actuator. On the one hand, the high speed of the electric motor can be translated via a first gear stage with a high ratio in such a way that a favorable torque is made available for the second gear stage . The actuating element can then be driven directly by means of the second gear stage, with a variable torque then being able to be generated in the second transmission ratio. Thus, on the one hand, a uniform positioning of the actuating element can be provided and, on the other hand, an increased torque or a high actuating force can be provided in the required areas of the actuating path. The design as a two-stage gear thus offers the advantage of a compact and therefore cost-effective design while at the same time providing different torques or actuating forces.

It can also be advantageous if the second gear stage is designed as an out-of-round gear stage. A non-circular gear stage is characterized by the fact that the rolling geometry on the drive wheel is designed with different rolling radii. A corresponding rolling geometry on the output wheel is then matched to the rolling radius of the drive wheel, so that continuous rolling between the operating wheel and the output wheel can be guaranteed. Due to the different rolling radii on the drive wheel, the torque to be generated can be varied in the non-round gear stage. Here, the non-circular gear stage is not limited to the formation of two meshing gears, but it can also be designed as a gear and the driven toothed element the drive wheel Have the form of a toothed rack, the toothed rack then being shaped accordingly in order to be able to engage in the rolling radius of the drive wheel and thus to ensure safe and functioning rolling.

If at least one gear stage is constructed as an involute gear stage, the actuating drive can in turn be designed in an advantageous manner. An involute toothing offers the advantage in relation to the involutes rolling on one another because, on the one hand, there is the possibility of high power transmission in the teeth and, on the other hand, low-noise rolling on the involute geometries. For example, if the actuator is equipped with two gear stages, a first worm gear can be arranged directly on the electric motor, for example, and the second gear stage can have involute gearing as a non-circular gear stage. In this way, the favorable meshing conditions in a worm gear and the highest possible transmission ratio in the worm gear can be combined with the advantages of the possible high power transmission in the involute-toothed second gear. This is of course only to be understood as an example, since of course both gear stages can also have involute gearing.

In order to be able to provide higher forces in the required areas, it can be advantageous to provide an increase in the transmission ratio in the second gear stage. A continuous transmission ratio can thus be present in a first range of the transmission, whereas the transmission ratio changes in a further partial range. Thus, for example, the actuating element can be moved constantly by means of a continuous range and, for example, be issued and change its actuating movement in a further second range, for example the end position, ie in an almost completely extended position. This can be advantageous if higher forces are to be made available in the end position. This can be advantageous, for example, when this end position represents a locked state for, for example, a charging plug of an electric or hybrid vehicle. In this end position, that is to say when the actuating element is fully extended, the actuating element or the locking pin can be at the mercy of the external environmental conditions. If, in extreme situations, icing occurs in the area of the charging plug and the locked state is to be released, a higher actuating force may be required to move the locking pin or the actuating element. If the second gear stage is now equipped with an increasing transmission ratio, higher actuating forces are available in the end position or in the partial area of the second gear stage, which release the locking pin from engagement with the charging connector named as an example. After the locking pin has been released, the actuating element can then be moved constantly by means of the second partial area of the gear mechanism.

The actuating element itself can also have part of a gear stage. The actuator can have two, three or more gear stages, but at least part of one of the gear stages, in particular a second gear stage, is arranged on the actuating element. The arrangement of part of the gear stages on the actuating element itself reduces the number of necessary gear parts to a minimum. A cost-effective actuating drive can thus be made available and at the same time a compact design of the actuating element is made possible.

A particularly compact embodiment is provided when two gear stages are provided, with a first gear stage directly affecting the actuating speed of the actuating element on the electric motor, whereas the second gear stage can be used to provide the required actuating forces. In particular, due to the construction according to the invention of an increasing transmission, an increased actuating force can be provided by the changed transmission ratio in the necessary areas of the actuating path of the actuating element. The transmission ratio is adjusted in such a way that an increased actuating force is provided at a reduced actuating speed.

As already shown above, it can be advantageous if the actuating element is designed as a toothed rack, at least in some areas. Preferably that will Actuating element is moved linearly, for example, out of a housing of the actuator. Of course, this is not meant to be restrictive, since the actuator itself can also be integrated into a housing of a charging socket, for example. A linear movement of the actuating element is preferred and is also previously known, for example, from DE 10 2017 125 819 A1. Thus, the drive by means of a toothed rack offers a constructively favorable option for producing a linear movement in the actuating element.

At least a portion of the toothed rack can also be straight and designed as a flat toothed rack, flat means that the teeth of the toothed rack are located in one plane, with the plane of the teeth being arranged parallel to a central axis of the actuating movement of the actuating element. The flat area of the toothed rack, in combination with a drive gear wheel for the toothed rack, then forms the area in which the actuating element can be adjusted with a uniform movement. A second portion of the rack then deviates from the plane and is designed in such a way that the transmission ratio between the drive wheel and the rack changes. An increase in the transmission ratio can be provided in an advantageous manner.

If the transmission ratio increases in the direction of an end position, preferably in both end positions, of the actuating element, an advantageous embodiment variant of the invention can in turn be achieved. The end positions are preferred positions in which higher actuating forces may be required. On the one hand, it can happen that the actuating element has not been moved for a longer period of time, and therefore, due to dirt and/or weather influences, the actuating element must be released from the starting position with a greater force. In order to ensure a high level of functional reliability, a higher actuating force can then be made available in the starting position through the variable transmission ratio. On the other hand, a higher actuating force may also be required in the extended position of the actuating element if, for example, the actuating element is used to lock a charging plug of an electric or hybrid vehicle, and for example the load can tilt or be pulled destecker it comes to a pinching of the actuating element, so that in turn higher actuating forces are required to move the actuating element. The starting position of the actuating element and the fully extended position of the actuating element can be determined as end positions.

Advantageously, the gear stages can be formed from a plastic, whereby on the one hand a low weight of the gear stages can be achieved and on the other hand a cost-effective manufacture of the gear components is made possible. Overall, by constructing at least one gear stage with a variable transmission ratio, at least in some areas, a high level of functional reliability can be ensured and there is the possibility of providing different actuating forces in the required positions of the actuating element.

The invention is explained in more detail below with reference to the accompanying drawings using exemplary embodiments. However, the principle applies that the exemplary embodiments do not limit the invention, but merely represent an advantageous embodiment. The features shown can be implemented individually or in combination with other features of the description as well as the patent claims individually or in combination.

It shows:

Figure 1 shows a basic representation of a drive concept in a flowchart representation,

FIG. 2 shows a detailed view of an actuating element with an out-of-round gear and an involute toothing as part of the drive train, and

FIG. 3 shows a further detailed view of an adjusting means with an out-of-round gear as part of the drive train. FIG. 1 shows a drive concept 1 in principle and in a representation of a flow chart. Shown is the transition from the electrical power Peiektr. towards the mechanical power Pmech. An electric motor 2 drives a drive wheel via an output shaft, the drive wheel together with an output wheel forming a first gear stage 3 . The first gear stage 3 is not tied to a toothing geometry or a type of gearing, but can be, for example, an evoloid gear, a toothed wheel gear, a worm gear or an involute gear. The first gear stage 3 interacts with a second gear stage 4, with a gear ratio that is preferably variable at least in certain areas being provided in the second gear stage. The second gear stage 4 drives the actuating element 5 directly or indirectly. Thus, starting from the electric motor 2, in which electrical energy is fed, the actuating element 5 moves via the gear stages 3, 4 and the electrical power Peiektr. in mechanical power Pmech. converted. Thus, the structure of the actuator according to the described drive concept 1 corresponds in essential points to the structure of the actuator according to DE 10 2020 101 363 A1, to whose disclosure content reference is made in its entirety. The drive concept 1 according to the invention differs in that there is a variable translation at least in one gear stage and at least in certain areas.

FIG. 2 now shows an actuating element 5 in a detailed view and as an integral part of a second gear stage 4 . The actuating element 5 is arranged in a housing 6 of an actuating drive 7 in such a way that the actuating element 5 can be moved out of the housing 6 and into the housing 6 in the direction of the arrow P. Thus, the actuating element 5 can represent a locking pin or locking pin. The second gear stage 4 is driven via the component electric motor 2 and the first gear stage 3, which are only shown in principle. The second gear stage 4 is equipped as a non-circular gear 4 with involute gearing. The pitch circles 8, 9 and the rolling radii 8, 9 of the second gear stage 4 are shown in FIG. 4 as a dot-dash line. It can be clearly seen that the gear wheel 10 has different rolling radii R1, R2, which produce a variable translation in the second gear stage 4.

The actuating element 5 can in principle be described as a toothed rack or as an actuating element with teeth, in particular involute teeth 11 . In this embodiment, the actuating element 5 can be moved linearly along a center line M, with the actuating element 5 being accommodated in the actuating drive 7 in a linearly displaceable manner. Due to the different radii R1, R2 on the gear wheel 10, different movement speeds and different torques or actuating forces can be introduced into the actuating element 5.

FIG. 2 shows the gear wheel 10 approximately in a central engagement of the actuating element 5. In this engagement position, a large actuating movement can be generated by the large radius R2. The gear 10 can be moved back and forth in the direction of the arrow P1, so that the meshing ratios change in the second gear stage. If the gear wheel 10 is moved clockwise, for example, the actuating element 5 is moved into the housing 6 . This changes the engagement ratios in the second gear stage, with an increasing translation being achievable. A larger actuating force can be introduced into the actuating element 5 by means of the smaller radii R1 on the gear wheel 10 . As a result, the actuator 7 is able to achieve variable actuating forces or moments that can be used, for example, for breaking ice. The use of a non-circular gear thus offers the advantage of high functional reliability even in extreme situations, with increased actuating forces being available for extreme situations.

FIG. 3 also shows an actuating element 12 as part of a second gear stage 4 in a detailed view of gear wheel 13 and actuating element 12 . In contrast to the exemplary embodiment according to FIG. 2, the pitch circles 14, 15 or rolling regions 14, 15 of the second gear stage 4 are designed to be variable only in one direction of movement of the gear wheel 13. In this exemplary embodiment, a variable transmission ratio is set in only one direction of movement of the gearwheel 13 . The variable translation results from the changing radii R1, R2 on the gear 13 and the course of the toothing 15 on the actuating element 12. A high actuating speed can be realized on the actuating element 12 over the radius R2, whereas with a movement of the gear 13, for example clockwise, high actuating forces F can be generated during the linear movement of the actuating element 12. Linear guides 16, 17 in the housing 6 of the actuator 7 can ensure linear guidance of the actuating element 12 along the center line M of the actuating element. As can be seen, the toothing 15 on the actuating element 12 as well as the toothing 14 on the gear wheel 13 is advantageously designed as an involute toothing.

The design of the non-circular gear in the form of an involute gear with a constant and variable translation is characterized in that the rolling of the toothed areas 14, 15 has a high level of efficiency. Depending on the requirements of the actuating element 5, 12 or locking pin 5, 12, different combinations of gear stages 3, 4 with different transmission ratios can be implemented. Advantageously, however, the use of an out-of-round gear with preferably increasing gear ratio can ensure a high level of functional reliability of the actuator 7 in extreme situations.

Reference List

drive concept

Electric motor first gear stage second gear stage

5, 12 actuator

6 housing

7 actuator

8, 9, 14, 15 pitch circles, pitch circles

10, 13 gear

1 1 involute toothing

16, 17 linear guides

pellet electrical power

P mech. mechanical performance

P, P1 arrow

R1 , R2 radius

M center line

F force

Claims

patent claims

1. Actuating drive (7) for automotive applications, in particular for locking devices, having an electric motor (2) and a drive train (3, 4) and an actuating element (5, 12) driven by the drive train (3, 4), wherein in the drive train (3, 4) at least one first and one second gear stage (3, 4) is provided, characterized in that at least one gear stage (3, 4) has a gear ratio that is variable at least in certain areas.

2. Actuator (7) according to claim 1, characterized in that the second gear stage (4) drives the actuating element (5, 12).

3. Actuator (7) according to one of claims 1 or 2, characterized in that the second gear stage (4) is designed as a non-circular gear stage.

4. Actuator (7) according to any one of claims 1 to 3, characterized in that at least one gear stage (3, 4) is designed as an involute gear stage.

5. Actuator (7) according to any one of claims 1 to 4, characterized in that the second gear stage (4) has an increasing transmission ratio.

6. actuator (7), characterized in that a first portion with a constant transmission ratio and a second portion of the at least one gear stage (3, 4) is formed with a variable transmission ratio.

7. Actuator (7) according to any one of claims 1 to 6, characterized in that at least part of the second gear stage (4) is arranged on the actuating element (5, 12).

8. Actuator (7) according to claim 7, characterized in that the actuating element (5, 12) is at least partially designed as a toothed rack.

9. Actuator (7) according to one of claims 1 to 8, characterized in that the transmission ratio in the direction of an end position, preferably in both end positions, of the actuating element (5, 12) increases.

10. Actuator (7) according to any one of claims 1 to 9, characterized in that the drive train, in particular the first and second gear stages (3, 4) are made of plastic.