Electric drives for automotive applications

Abstract

The invention relates to an electric drive for automotive applications comprising an electric motor (1), a drive wheel (3), in particular a worm wheel (3), interacting with said electric motor (1) and having a cam profile (5), and a lever (8) capable of impacting said cam profile (5). This cam profile (5) completes a full rotation (360°) in order to impact the lever (8). According to the invention, this cam profile (5) is designed to perform more than a full rotation (>360°).

Description

[Technical Field]

[0001]

[0001] The present invention relates to an electric motor drive for automotive applications, the drive having an electric motor and further having a drive wheel, in particular a worm wheel, interacting with the electric motor and having a cam profile and a lever actable by the cam profile, the cam profile completing a full rotation (360°) to act on the lever.

[0002]

[0002] Electric motor drives for automotive applications are characterized by a robust design and the possibility of operating at low voltages, typically 12 or 24 V DC. As a result, special means are often required to transmit the rotary motion of the electric motor to achieve power-consuming operation. Such ratios are usually provided by the electric motor engaging the external teeth of a worm and worm wheel mounted on its output shaft. Furthermore, the cam profile typically has a helical edge, which allows an increasing torque to be applied to a lever abutting the cam profile, acting with the help of the helical edge of the cam profile.

[0003] This has proven successful in principle, so that such electric drives are used, for example, to control shutters, as described in the general DE 197 02 420 C5. In fact, the control element or actuator realized in this way can realize the function positions "open," "lock," "anti-theft" and finally "child-safe," which correspond to rotational movements of the worm wheel of 0° or 360°, 90°, 180° and finally 270°. This has been proven in principle.

[0004]

[0004] Furthermore, comparable electric drives have recently been used in connection with the operation of lock actuators in charging devices connected to electric or hybrid vehicles. Other uses for such electric drives include providing window lifting, mirror adjustment, and even seat adjustment. They can also be used to unlock and lock lids. Furthermore, such electric motor drives are used inside vehicle latches or as pull / open drives. These drives are always characterized by high-speed electric motors, whose high rotational speeds, in contrast, translate into relatively slow movements with increased force or increased torque, resulting in large transmission ratios.

[0005]

[0005] It is true that intermediate gearboxes can be provided in this context. However, these increase the technical effort and friction and are therefore usually avoided and not considered goal-oriented. Nevertheless, efforts to increase the translational movement already provided remain constant. Currently, there is no constructively simple and cost-effective solution available for this. The present invention seeks to remedy this as a whole.

[0006] overview

[0007]

[0006] The present invention is based on the technical problem of further developing such an electric motor drive for automotive applications so that it is possible to increase the transmission ratio while at the same time being simple and cost-effective in design.

[0008]

[0007] In order to solve this technical problem, the present invention proposes that in a general electric motor drive for automotive technical applications, the cam profile is configured to achieve more than a full rotation (>360°).

[0009]

[0008] In order to be able to realize and translate more than a full rotation (>360°) of the drive wheel, in particular the worm wheel, the lever is provided with at least one first lever stop, and the drive wheel, in particular the worm wheel, is provided with a wheel stop, with which both stops interact in a position-dependent manner. That is, the lever stop is arranged on the lever acted upon by the cam profile, while the wheel stop is found on the drive wheel, in particular the worm wheel. As a result of the movement of the drive wheel, in particular the worm wheel, and therefore of the cam profile, and generally the pivoting movement of the lever generated thereby, both stops can interact in a position-dependent manner. In most cases, the first lever stop interacts with the wheel stop as an end stop after the drive wheel, in particular the worm wheel, has rotated a full rotation.

[0010] Advantageously, and therefore particularly preferably, the drive wheel is designed as a worm wheel. However, it is also conceivable to design the drive gear as a toothed wheel or the like.

[0011]

[0010] Overall, the invention is based on the knowledge that the lever, and with it the first lever stop, is pivoted by impact with a portion of the cam profile during the transverse movement of the drive wheel, in particular the worm wheel. As soon as the drive wheel, in particular the worm wheel, has completed more than a full rotation, the first lever stop engages with the wheel stop and the aforementioned interaction is observed. Thus, after this full rotation of the drive wheel, in particular the worm wheel, the first lever stop and the wheel stop together act as an end stop, whereby the drive wheel, in particular the worm wheel, is slowed down and does not "overrun"

[0012]

[0011] In the prior art according to DE 199 48 052 A1 or DE 103 61 168 A1, stops have already been described in this context, but not in the form of a combination of a first lever stop and a wheel stop which interact depending on the position.

[0013] The present invention is based on the further realization that providing a portion of the cam profile with more than a full rotation can be employed to utilize the cam profile to transmit a much higher transmission ratio to the lever than in the prior art. As a result, the lever can perform a desired positioning movement with a greater torque than in the prior art. This can include representing the functional state of an interior automobile latch, opening and closing an automobile door, raising or lowering an automobile window, to name a few examples of applications and possible control elements that can be actuated by the lever.

[0014]

[0013] Nevertheless, to ensure that the electric drive is decelerated and stopped after the completion of the relevant positioning movement, thereby preventing the aforementioned "overrun movement," the first lever stop acts as an end stop together with the wheel stop and jointly defines such a stop at the end of more than a full rotation of the drive wheel. This arrangement utilizes the pivoting movement of the lever, and therefore the first lever stop, so there is no possibility of the first lever stop colliding with the wheel stop before or during the pivoting movement of the lever, nor is there any rotational movement of the drive wheel. Rather, the first lever stop does not pivot within the typical circular path of the wheel stop on the outer periphery of the drive wheel until the lever reaches its final pivot position, which is the case after the drive wheel has rotated a full rotation. For this purpose, the first lever stop is typically located at the end of the lever away from the axis.

[0015] The lever is usually a two-armed lever having a first arm and a second arm. The first arm is usually provided with a first lever stop at its end. In contrast, the second arm acts on a control element. This can be done directly or indirectly. The two arms can be of equal or different lengths relative to the central axis or axis of rotation.

[0016] In addition to the possibility that the first lever stop interacts with the wheel stop as an end stop, after the full working movement of the lever is completed, i.e., after the full rotation of the drive wheel, the first lever stop can also interact with the cam profile as an end stop. In this case, this end stop is regularly defined and realized at the beginning of the stroke movement. For this purpose, the cam profile typically has a recess for the lever, preferably close to the axis.

[0017]

[0016] As a result, the lever can enter the recess and thus the cam profile at the beginning of the actuating movement of the drive wheel. In this way, it is advantageous for the recess to be designed so that it interacts with the first lever stop as a further end stop at the beginning of the rotational movement of the drive wheel. Starting from the positioning of the lever or its first arm with the first lever stop in the recess, the rotational movement of the drive wheel gradually pivots the lever with the help of the cam profile, usually radially outward relative to the axis of the drive wheel. This pivoting movement continues until the application of the lever by the cam profile is completed, and ends when the drive wheel has completed more than a full rotation, and then the first lever stop interacts with the wheel stop on the drive wheel as an end stop.

[0018] However, within the scope of another variant having independent significance, the lever can also be provided with a second lever stop, which is furthermore designed to interact with the wheel stop depending on its position, as in the case of the first lever stop and the wheel stop.

[0019]

[0018] In most cases, the first lever stop, as before, interacts with the wheel stop as an end stop after the full rotation of the drive wheel, and the second lever stop, in this variant, interacts with the wheel stop as an additional end stop at the beginning of the rotational movement of the drive wheel. That is, at the beginning of the rotational movement of the drive wheel, a second lever stop is defined. At the end of the rotational movement of the drive wheel in both variants, the first lever stop and the wheel stop interact as an additional end stop. As a result, the rotational movement of the drive wheel between the two end stops is mechanically fixed, eliminating the risk of overrun when the lever is loaded or the electric drive is reversed. In this way, the control element operated by the lever can be moved with particular precision.

[0020] As a result, an electric drive for motor vehicle applications is provided, which, thanks to the possibility of the cam profile realizing more than a full rotation, can transmit a particularly high transmission ratio starting from the electric motor via the drive wheel and the cam profile to a lever for acting on the desired control element. For example, the lever can be connected directly or indirectly to the catch of a vehicle door latch in order to activate the latch in the sense of a pulling action and pull the associated vehicle door. Of course, other applications are also conceivable, as already mentioned in the introduction.

[0021]

[0020] A further subject of the present invention is therefore a vehicle latch, in particular a vehicle door latch with such an electric drive. In this case, the vehicle latch can be electrically opened using an actuator. This is achieved indirectly by actuating a release lever or directly by applying pressure to the pawl. Furthermore, locking functions such as child safety locks, anti-theft devices, central locking systems, etc. can be inserted and implemented individually or in combination with the help of the associated drives.

[0022]

[0021] Since the drive wheel is usually designed as an injection-molded part, the drive wheel including the cam profile can be produced particularly easily and cost-effectively. Embodiments made of metal or plastic prove their worth here. In connection with at least one additional lever stop or two lever stops, a particularly simple design is provided. In fact, the lever itself can also be made of plastic or metal. As a result, only low manufacturing costs are observed. This is an essential advantage. [Brief explanation of the drawings]

[0023] The invention will now be explained in more detail with reference to the drawings, which show only one exemplary embodiment. [Figure 1A] FIG. 1A shows a first variant of the invention illustrating the rotational movement of the drive wheel. [Figure 1B] FIG. 1B shows a first variant of the invention illustrating the rotational movement of the drive wheel. [Figure 2A] FIG. 2A shows a second variant of the modified embodiment. [Figure 2B] FIG. 2B shows a second variant of the modified embodiment.

[0024] Detailed Description

[0025] The figures show a representative example of an electric drive for automotive applications. For this purpose, the drive has an electric motor 1 operating at a low DC voltage, for example 12 V, 24 V, or 48 V. An output worm 2 is arranged on the output shaft of the electric motor 1, which meshes with the external teeth of a worm wheel 3. This allows the worm wheel 3 to perform a counterclockwise movement about its axis 4, as shown in particular in FIGS. 1A and 1B. During this counterclockwise movement, starting from the respective home or rest position according to FIGS. 1A and 2A, the worm wheel 3 completes more than a full rotation (>360°) according to the exemplary embodiment. This can be seen in particular in FIG. 1B, whereby the worm wheel 3 and the cam profile 5 arranged thereon complete a full rotation when moving from FIG. 1A to FIG. 1B or from FIG. 2A to FIG. 2B, after which a further angle of approximately 35° is swept in this example. That is, the worm wheel 3 and with it the cam profile 5 complete a total angle of almost 400° in the two exemplary embodiments, i.e. 360° + approximately 35°. Of course, this applies only as an example and is not limiting.

[0026] The positioning movement of the electric drive, and thus of the worm wheel 3, in the sense of a counterclockwise movement about the axis 4 shown, corresponds to the action of a cam profile 5 on the worm wheel 3 on a plastic or metal lever 8. For this purpose, the cam profile 5 is provided with a helical edge 7, which starts from a recess 6 in the cam profile 5 close to the axis. That is, the worm wheel 3 is provided with a helical cam profile 5 having a recess 6 near one end of the axis and a helical edge 7 at the other end. The helical edge 7 is characterized by a radius that starts from the recess 6 and increases in the direction of actuation or counterclockwise relative to the axis 4, so that the lever 8, acting on the cam profile 5 and sliding along the helical edge 7, is subjected to an increasing torque.

[0027]

[0025] In fact, the lever 8 is a two-armed lever which, according to the present embodiment, is mounted rotatably in a housing about a central axis 9. The housing may be that of an automobile latch or pull drive, a window regulator drive, a flap drive, etc. The lever 8 acts indirectly or directly on a control element 10. In fact, as can be seen when moving from Figure 1A to Figure 1B and from Figure 2A to Figure 2B, the movement of the lever 8 is transmitted to the control element 10 in a clockwise direction about its axis 9.

[0028] In the case of a pull-open drive, the control element 10 may, although not explicitly shown, be the catch of the vehicle door latch already mentioned. In principle, however, the control element 10 may also be a liftable window pane, a vehicle door, a vehicle flap, etc. For this purpose, the lever 8 completes a positioning movement, shown respectively in FIGS. 1B and 2B, about its axis 9 in a clockwise direction with increasing torque.

[0029] As already explained, according to the device of the invention, the cam profile 5 is configured in this embodiment to achieve more than a full rotation (>360°) and is capable of a rotational movement of approximately 400°. The lever 8 is equipped as a two-armed lever with a first arm 8a and a second arm 8b. The further second arm 8b interacts with the control element 10. In contrast, the first arm 8a abuts against the cam profile 5 or its helical edge 7 and is pivoted clockwise about its axis 9 by the counterclockwise movement of the worm wheel 3.

[0030] 1A and 2A, the two-armed lever 8, in its basic position according to FIGS. 1A and 2A, sinks with its first arm 8a into the recess 6 of the cam wheel 5. Starting from this basic position according to FIGS. 1A and 2A and the associated setting angle of 0° relative to the cam profile 5 and thus to the worm wheel 3, a counterclockwise rotational movement of the worm wheel 3 and thus of the cam profile 5 about its axis 4 moves the helical edge 7 of the cam profile 5 relative to the arm 8a of the lever 8. In the illustrated embodiment, the cam profile 5 and thus the helical edge 7 extend in a plane parallel to the worm wheel 3. As the distance of the helical edge 7 from the axis 4 of the worm wheel 3 increases, the arm 8a of the lever 8 rotates more and more about its axis 9, i.e. in the clockwise direction, and the control element 10 is thus subjected to the desired load.

[0031] As a result of the fact that the cam profile 5 completes a full rotation of more than 360° during this process, the overall transmission ratio provided by the electric motor 1 can be increased, which ultimately acts on the lever 8. Nevertheless, in order to be able to precisely slow down and stop the electric motor 1 at the end of this movement, the lever 8 is provided with at least one first lever stop 11, and the worm wheel 3 is provided with a wheel stop 12, with both stops 11, 12 interacting in a position-dependent manner. Position-independent interaction means that the two stops 11, 12 interact or not depending on the position of the worm wheel 3, on the one hand, and the lever 8, on the other hand. In this embodiment, the interaction between the first lever stop 11 and the wheel stop 12 only occurs when the worm wheel 3 has completed a full rotation of more than approximately 400° in the exemplary case. That is, the first lever stop 11 interacts with the wheel stop 12 as an end stop 11, 12 after the worm wheel 3 has completed a full rotation. This situation is illustrated in Figures 1B and 2B.

[0032]

[0030] In practice, it can be seen that the wheel stop 12 is first mounted on the outer periphery of the worm wheel 3, as is the upper or front cam profile 5 of the worm wheel 3 shown in the figures. As a result, starting from the basic position according to FIGS. 1A and 2A, the wheel stop 12 performs a counterclockwise movement about the axis 4, and in the exemplary case reaches the position according to FIG. 1B or 2B at the end of a set movement of about 400°. The first lever stop 11 is found in the basic position according to FIGS. 1A and 2A, inside the recess 6 of the worm wheel 3, immediately adjacent to the axis 4. By rotating the worm wheel 3 counterclockwise, the helical edge 7 rests on the arm 8a of the lever 8 or on the first lever stop 11, so that when the arm 8a rests on the helical edge 7, the arm 8a is gradually pivoted radially outwards relative to the axis 4. As a result, the lever 8 completes the clockwise movement shown in Figure 1B and Figure 2B respectively, and the further second arm 8b of the lever 8 ensures that the control element 10 is acted upon.

[0033] Only at the end of the spiral edge 7 does the first lever stop 11 enter the range of influence of the wheel stop 12 or pivot into its path on the outer periphery of the worm wheel 3, and the wheel stop 12 moves or pivots into its path of movement relative to the first lever stop 11, so that the further counterclockwise rotational movement of the worm wheel 3 is slowed down. Thus, after the worm wheel 3 has rotated completely, the first lever stop 11 and the wheel stop 12 together act as end stops 11, 12.

[0034]

[0032] For this reason, in this embodiment, the first lever stop 11 is arranged at the end of the lever 8 remote from the axis. Furthermore, in relation to the first exemplary embodiment shown in Figures 1A and 1B, the design is such that the first lever stop 11 interacts with the cam profile 5 as a further end stop. For this purpose, the cam profile 5 has a recess 6 near the axis of the lever 8, which recess 6 interacts with the first lever stop 11 at the start of the rotational movement of the worm wheel 3 and acts as a further end stop 6, 11. This is shown in Figure 1A, where it can be seen that at the start of the rotational movement of the worm wheel 3, the lever 8 or its first lever arm 8a enters the recess 6 of the cam profile 5. The first lever stop 11, which is arranged at the end of the lever 8 or at the end of the first lever arm 8a remote from the axis, drives in this basic position relative to the recess 6 according to Figure 1A and thus defines a further end stop 6, 11 together with the first lever stop 11.

[0035] 2A and 2B show a variant in which the first lever stop 11 is still implemented and interacts with the wheel stop 12 as an end stop 11, 12 even after two or more full rotations of the worm wheel 3, as clearly shown in FIG. 2B. However, the situation is different at the start of the rotational movement of the worm wheel 3: in this case, as shown in FIG. 2A, the first lever stop 11 does not move relative to the recess 6 or the end of the recess 6, but rather is spaced apart. Nevertheless, in order to achieve a mechanically defined and fixed position, in the exemplary embodiment according to FIGS. 2A and 2B, the lever 8 is provided with a further second lever stop 13. Like the first lever stop 11, the second lever stop 13 also interacts with the wheel stop 12 as a function of its position. Indeed, at the start of the rotational movement of the worm wheel 3 in FIG. 2A, an interaction between the additional second lever stopper 13 and the wheel stopper 12 is observed, while the first lever stopper 11 interacts with the wheel stopper 12 as an end stop 11, 12 as usual at the end of the rotational movement of the worm wheel 3.

[0036]

[0034] In fact, the second lever stop 13 and the wheel stop 12 define another end stop 13, 12 at the start of the rotational movement of the worm wheel 3. This is shown and can be directly understood in Figure 2A.

[0037]

[0035] For this purpose, the wheel stop 12 is a ridge-type stop 12 arranged on the front or upper outer periphery of the worm wheel 3 and extending radially relative to the axis 4 of the worm wheel 3. The ridge-type wheel stop 12 thus has two opposing stop surfaces 12a, 12b on the ridge. The stop surface 12a is mounted on the front side in the direction of movement (counterclockwise) of the ridge-type stop 12, while the further second stop surface 12b is arranged at the rear. The same result applies to the first exemplary embodiment. As a result, at the start of the rotational movement within the scope of the representation according to FIG. 2A, the stop 12, together with the stop surface 12b, rests against the second lever stop 13 of the lever 8.

[0038]

[0036] Now, starting from this basic position according to Fig. 2A, the worm wheel 3 is moved counterclockwise about its axis 4, moving the stop 12 away from the second lever stop 13, until the latter is in the position according to Fig. 2B. In this functional position, the lever 8 has been pivoted radially outwards by the cam profile 5 to the position shown in Fig. 2B, so that the first lever stop 11 enters the path of the stop 12, and the stop 12 moves its front stop face 12a against the first lever stop 11. In both cases, the electric drive is mechanically stopped and slowed down.

[0039]

[0037] The possibility is not shown that the cam profile 5 does not have an in-plane helical edge 7, but instead has a helical spiral profile. In this case, the arm 8a of the lever 8 interacting with the cam profile 5 can be provided, for example, with a roller which spatially follows the helical spiral profile of the cam profile 5. Thus, the two-armed lever 8 does not complete a pivoting movement about its axis 9, but rather is moved upwards about an axis lying in the plane of the drawing, so that the other arm 8b completes a downward movement which can be transmitted to the control element 10. [Explanation of symbols]

[0040] 1...electric motor, 2...Output warm, 3...Drive wheel / worm wheel, 4...axis, 5...cam outer shape part, 6...(near the axis) recess, 7...Spiral edge, 8...lever, 9...Intermediate shaft, 10...control element, 11...first lever stopper, 12...Wheel stopper, 11, 12...end stops, 12a, 12b...stop surface, 13...Second lever stopper, 13, 12...further end stops.

Claims

1. an electric motor (1); a drive wheel (3) interacting with said electric motor (1) and having a cam profile (5); a lever (8) that can act on the cam profile (5); An electric drive device for automotive applications, comprising: The cam profile (5) is configured to complete a full rotation (360°) to act on the lever (8) and the cam profile (5) is configured to achieve more than a full rotation (>360°); A drive device characterized in that the lever (8) is provided with at least one first lever stop (11) and the drive wheel (3) is provided with a wheel stop (12), and both stops (11, 12) interact with each other in a position-dependent manner.

2. 2. A drive device according to claim 1, characterized in that the drive wheel (3) is a worm wheel (3).

3. 3. The drive device according to claim 2, characterized in that the first lever stop (11) interacts with the wheel stop (12) as an end stop (11, 12) after more than a full rotation of the drive wheel (3).

4. 4. The drive device according to claim 3, characterized in that the first lever stop (11) is arranged at the end of the lever (8) remote from the axis.

5. 5. Drive device according to claim 4, characterized in that the first lever stop (11) interacts with the cam profile (5) as a further end stop.

6. 6. A drive device according to claim 5, characterized in that the cam profile (5) has a recess (6) relative to the lever (8).

7. 7. The drive device according to claim 6, characterized in that the recess (6) interacts with the first lever stop (11) as a further end stop (6, 11) at the start of the rotational movement of the drive wheel (3), in particular the worm wheel (3).

8. 8. The drive device according to claim 7, characterized in that the lever (8) is provided with a further second lever stop (13), which interacts with the wheel stop (12) in a position-dependent manner.

9. 9. The drive device according to claim 8, characterized in that the first lever stop (11) interacts with the wheel stop (12) as the end stop (11, 12) after more than a full rotation of the drive wheel (3), and the second lever stop (13) interacts with the wheel stop (12) as a further end stop (13, 12) at the start of the rotational movement of the drive wheel (3), in particular the worm wheel (3).

10. A latch for a motor vehicle, in particular a latch for a motor vehicle door, characterized by an electric drive device according to any one of claims 1 to 9.

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