Electric drive systems for automotive applications

Abstract

The invention relates to an electric drive for automotive applications, comprising an electric motor (1), a drive wheel (3) interacting with said electric motor (1), in particular a worm wheel (3) 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 device for automotive applications. This drive device has an electric motor and further has a drive wheel, particularly a worm wheel, interacts with the electric motor and has a cam profile, and has a lever that can be actuated by the cam profile. The cam profile completes a full rotation (360°) in order to act on the lever.

[0002]

[0002] An electric motor drive device for automotive applications is characterized by a robust design and the possibility of operating at a typically low voltage of 12V or 24V DC. As a result, special means are often required for the transmission of the rotational movement of the electric motor in order to achieve a power-consuming operation. Such a ratio is usually provided by the engagement of a worm placed on its output shaft with the external teeth of a worm wheel. Furthermore, the cam profile typically has a spiral edge, by means of which it can act with the aid of the spiral edge of the cam profile and apply an increasing torque to the lever in contact with the cam profile.

[0003]

[0003] This has proven to be basically successful, so that such an electric drive device is used, for example, to control a shutter, as described in the general DE 197 02 420 C5. In fact, the adjustment element or actuator realized in this way can realize the functional positions "open", "lock", "theft prevention" and finally "child safety" corresponding to the rotational movement of the worm wheel of 0° or 360°, 90°, 180° and finally 270°. This has been proven in principle.

[0004]

[0004] More recently, similar electric drive devices have been used in connection with the operation of lock actuators in charging devices connected to electric or hybrid vehicles. Other examples of use of such electric drive devices include providing the raising and lowering motion of window panes, mirror adjustment, and even seat adjustment. They can also be used for unlocking and locking lids. Furthermore, such electric motor drive devices are used inside the locks of vehicles or as pull / open drive devices. These drive devices are always characterized by high-speed electric motors, whose high rotational speed is converted in contrast to relatively slow motion with increased force or increased torque, resulting in a large transmission ratio.

[0005]

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

[0006] overview

[0007]

[0006] The present invention is based on the technical challenge of further developing such electric motor drive systems for automotive applications that can increase the transmission ratio while being simple and cost-effective in design.

[0008]

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

[0009]

[0008] In connection with this, to prevent collision with a stationary stopper, the cam outer shape is typically equipped with a flexible stopper. The stopper is usually a clamping means that interacts with the drive wheel, in particular the worm wheel. Advantageously, the drive wheel is designed as a worm wheel. Alternatively, the drive gear may be configured as a toothed wheel or the like.

[0010]

[0009] The present invention is, firstly, based on the knowledge that the realization of rotation beyond the full rotation of a portion of the cam outer shape can be used or engaged in so that, with the help of the cam outer shape, a higher transmission ratio than that of the prior art can be transmitted to the lever. As a result, the lever can perform the desired positioning movement with a larger torque than in the prior art. Some examples of applications include typical functional states in automotive latches, opening and closing movements on automotive door latches, raising or lowering automotive windows, and so on.

[0011]

[0010] Nevertheless, a flexible stopper is implemented so that the electric drive can be decelerated and stopped after the completion of the associated positioning motion. This means that no "overrun" motion of the drive is observed. This is because, with the help of such a flexible stopper, the desired rotation of the cam outer shape beyond 360° can be easily put into practice without fear of collision with a stationary stopper. Rather, the stopper is advantageously designed as a clamping means that interacts with the drive wheel, in particular the worm wheel, and has proven to be able to decelerate the cam outer shape, and thus decelerate the drive wheel, in particular the worm wheel, at the end of its positioning motion or at the beginning after a reverse motion. Due to the flexibility of the clamping means, this braking process can also be considered "soft" compared to a "hard stop", so such a design has the additional advantage that any damage to the electric drive caused by a hard stop is avoided.

[0012]

[0011] According to an advantageous design, the clamping means is fixed on one side to the drive wheel, particularly the worm wheel, and on the other side to the stationary stopper. Furthermore, it is advantageous that the drive wheel, particularly the worm wheel, has a guide outer shape for the clamping means. Thus, the guide outer shape can be used to "wrap" the clamping device around the drive wheel, particularly the worm wheel. To prevent collision with the cam outer shape at this location, the guide outer shape is provided and designed to be positioned opposite the cam outer shape on the drive wheel, particularly the worm wheel.

[0013]

[0012] That is, the cam outer shape and the lever that contacts and interacts with it to apply the desired adjustment element are located on one side of the drive wheel, particularly on the upper or front side of the worm wheel. In contrast, the rear side of the drive wheel, particularly the rear side of the worm wheel, is typically provided with a guide outer shape. The clamping means is connected to the drive wheel, particularly the worm wheel, and one end is usually adjacent to or even connected on the guide outer shape, so that the rotational motion of the drive wheel, particularly the worm wheel, causes the clamping means to contact the worm wheel around the guide outer shape, thereby winding onto the drive wheel, particularly the worm wheel.

[0014]

[0013] In this regard, it has been found to be particularly advantageous when the clamping device is designed in a strip-like form. In principle, the clamping means may also be a spring, for example, a helical spring. However, the present invention usually uses a strip-like tensioning means that allows for flexible length changes of 20% or more, preferably 50% or more. This means that the length of the strip-like tensioning means can be stretched or expanded by more than 20%, more than 50%, or more without observing damage at this location.

[0015]

[0014] For this purpose, it is advantageous that the clamping means be made entirely or partially of an elastic material. Here, it has been found that elastic plastics such as elastomers are particularly preferred. In principle, the clamping device can also be made of a woven fabric. Also, a combination of elastomer and fibers can of course be considered, for example.

[0016]

[0015] The cam outer shape typically has a recess for a lever, preferably near the shaft. That is, the recess is found close to or adjacent to the shaft of the drive wheel, particularly the worm wheel. The helical edge or helical shape of the cam outer shape generally arises from this recess. The helical edge or helical shape traces two or more full rotations of the drive wheel, particularly the worm wheel, around the aforementioned shaft.

[0017]

[0016] When the cam outer shape is positioned in a plane, the cam outer shape has the helical edge in the plane, which increases the radial distance on the lever and acts on the adjustment element. However, in principle, a helical outer shape having a helical extension relative to the axis of the drive wheel / worm wheel can also be realized in this location, thus tracing a rotation beyond the full rotation around the axis. The helical shape of the helical outer shape means that the helical outer shape and the cam outer shape together have a spatial or three-dimensional design as a whole. In such a case, the helical outer shape of the spiral again ensures that the lever interacting with it is acted upon by the helical outer shape to initiate the desired movement of the adjustment element.

[0018]

[0017] As a result, the possibility of the cam's external shape enabling rotation beyond full rotation provides an electric motor drive for automotive applications that can transmit a particularly high transmission ratio from the electric motor through the drive wheel, in particular the worm wheel and the cam's external shape, to a lever for acting on a desired adjustment element. For example, the lever may be directly or indirectly connected to a rotary latch to actuate the latch in the sense of a closing motion to close the associated automotive door. Of course, other applications already described in the introduction are also possible.

[0019]

[0018] Accordingly, an additional subject of the present invention is an automotive latch, in particular an automotive door lock, equipped with such an electrically driven device. The automotive lock can be electrically opened using an actuator. This is achieved indirectly by acting on a release lever, or directly by applying pressure to the claw portion. Furthermore, locking functions such as child safety locks, anti-theft devices, and central locking systems can be inserted and implemented individually or in combination with the help of related drive devices.

[0020]

[0019] Drive wheels, especially worm wheels, are typically designed as injection-molded parts, so that drive wheels, especially worm wheels, including the cam outer shape, can be produced particularly easily and cost-effectively. Designs made of metal or plastic are demonstrated and tested here. In relation to flexible stoppers designed as strip-shaped clamping devices, particularly simple designs are provided and converted, which also only come with low manufacturing costs. Herein lies an essential advantage. [Brief explanation of the drawing]

[0021]

[0020] The present invention will be described in more detail below with reference to drawings showing only one exemplary embodiment. [Figure 1A] Figure 1A shows a front view of the electric drive device according to the present invention in one of two different functional positions. [Figure 1B] Figure 1B shows a front view of the electric drive device according to the present invention in one of two different functional positions. [Figure 2A] Figure 2A shows a rear view of the electric motor drive unit according to Figures 1A and 1B. [Figure 2B] Figure 2B shows a rear view of the electric motor drive unit according to Figures 1A and 1B. [Figure 2C] Figure 2C shows a rear view of the electric motor drive unit according to Figures 1A and 1B.

[0022] Detailed explanation

[0023]

[0021] The figure shows an electric motor drive system for automotive applications. For this purpose, the drive system has an electric motor 1 that operates at a low DC voltage, for example, 12V, 24V, or 48V. An output worm 2 that meshes with the external teeth of a worm wheel 3 is positioned on the output shaft of the electric motor 1. This allows the worm wheel 3 to move counterclockwise around its axis 4, as shown in particular in Figures 1A and 1B. The counterclockwise motion in the front view shown in Figures 1A and 1B corresponds to the clockwise motion in the rear view shown in Figures 2A to 2C. In principle, it is also possible to have clockwise motion in the front view and the corresponding counterclockwise motion in the rear view.

[0024]

[0022] The worm wheel 3 is provided with a helical cam outer shape 5. The cam outer shape 5 has a recess 6 near one axis and a helical edge 7 near the other axis. The helical edge 7 is characterized by starting from the recess 6 and increasing radius in the operating direction (counterclockwise in the front view shown in Figures 1A and 1B), and as a result, the lever 8 acted upon by the cam outer shape 5 is subjected to an increasing torque. The lever 8 is a two-arm lever made of, for example, plastic or metal, and in this embodiment, it is rotatably mounted in the housing around the axis 9. The housing may be the housing for an automobile lock or pull drive device, a window regulator drive device, a flap drive device, etc.

[0025]

[0023] According to this embodiment, the lever 8 is used to operate the adjustment element 10. In the case of a pull drive, the adjustment element 10 may be the rotary latch (not shown) of the latch for an automotive door described above. However, in principle, the adjustment element 10 may be an elevating window glass, an automotive door, an automotive flap, or the like. For this purpose, the lever 8 can perform the operating movement shown in FIG. 1B, which, as can be understood by comparing FIGS. 1A and 1B, corresponds, according to the embodiment, to the lever 8 being pivoted clockwise about its axis 9 from its initial position in FIG. 1A.

[0026]

[0024] The feature according to the invention is that, as can be understood by comparing FIGS. 1A and 1B, the cam profile 5 acting on the lever 8 is not only capable of performing a movement in the sense of a full rotation through 360°. In fact, in FIG. 1A, the initial position of the cam profile 5 corresponding to 0° is represented, and in FIG. 1B, the final position of the cam profile 5 corresponding to an angle greater than 360° is reproduced. In fact, in the case of the illustrated embodiment, an angle of approximately 400° in total, that is, an angle obtained by adding approximately 35° to 360°, has been completed. Of course, this applies only as an example and is not restrictive.

[0027]

[0025] That is, according to the invention, the cam profile 5 is configured to achieve a full rotation or more exceeding 360° about the associated axis 4 of the worm wheel 3. To achieve this and convert it in detail, the two-armed lever 8, together with one of its arms 8a, drops into the recess 6 of the aforementioned cam profile 5. On the other hand, the other arm 8b of the two-armed lever 8 acts, directly or indirectly as required, on the adjustment element 10 which is merely shown. The adjustment element 10 may be the rotary latch, window glass, automotive door, or the like described above.

[0028]

[0026] Starting from a basic position according to the setting angle of 0° in Figure 1A with respect to the cam outer shape 5, as the worm wheel 3, and therefore the cam outer shape 5, rotates counterclockwise around the axis 4, the helical edge 7 of the cam outer shape 5 moves relative to the arm 8a of the lever 8. In the illustrated embodiment, the cam outer shape 5, and therefore the helical edge 7, extends 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 increasingly around the axis 9, i.e., clockwise, and so the adjustment element 10 receives the desired load.

[0029]

[0027] As a result of the fact that the cam outer shape 5 completes a full rotation exceeding 360° during this process, the overall transmission ratio provided by the electric motor 1 can be increased, thereby finally acting on the lever 8. Nevertheless, in order to ensure that the electric motor 1 can be precisely decelerated and stopped at the end of this motion, a flexible stopper 11, which can be understood from the rear view according to Figures 2A to 2C, is additionally implemented.

[0030]

[0028] In fact, the stopper 11 is designed as a clamping means 11 that interacts with the worm wheel 3. Thus, the clamping means 11 is fixed to the worm wheel 3 on one side and to the stationary stopper 12 on the other. The worm wheel 3 also has a guide outline 13 for the clamping means 11. In an exemplary embodiment, the guide outline 13 is a ring-shaped or annular outline that surrounds the axis 4 of the worm wheel 3 at a certain distance. It can be seen that one end of the clamping means 11 is fixed to or engages with the guide outline 13, and the other end of the clamping means 11 is connected to the stationary stopper 12.

[0031]

[0029] In this regard, the cam outer shape 5 is designed to be positioned on the front or upper side of the worm wheel 3 as seen in Figures 1A and 1B. In contrast, a guide outer shape 13 is machined on the rear side of the worm wheel 3, as can be seen from the rear view in Figures 2A-2C. The cam outer shape 5 and the guide outer shape 13 are manufactured integrally with the worm wheel 3, for example, as an injection-molded part. This can be made of plastic and / or metal.

[0032]

[0030] Figures 2A to 2C further clarify that the clamping means 11 is designed in a strip-like form. Furthermore, the strip-like tensioning means 11 allows for flexible length changes of 20% or more, preferably 50% or more. This means that when the strip-like tensioning means 11 is subjected to an axial load, its length can be increased by 20% or more, preferably 50% or more, but it can return to its original state flexibly and without damage after the axial load is removed. For this purpose, the clamping means 11 is made entirely or partially of an elastic material. This can be an elastic plastic, for example, NR (natural rubber). In principle, woven fabrics or combinations can also be considered here.

[0033]

[0031] In any case, the corresponding clockwise motion of the worm wheel 3 due to the load on the lever 8 by the cam outer shape 5 moving counterclockwise, as shown in the front views of Figures 1A and 1B, is reproduced in the rear views according to Figures 2A to 2C. As seen in the sequence from Figures 2A to 2C, the clockwise motion corresponds to the fact that the clamping means 11 is set relative to the circumference of the annular guide outer shape 13 and is wound up on the guide outer shape 13. This is in principle the same even when the worm wheel 3 has completed its counterclockwise reversal motion.

[0034]

[0032] It has not been shown that the cam outer shape 5 does not have an in-plane helical edge 7, but instead has a spiral-shaped outer shape extending in a string-like manner. In this case, the arm 8a of the lever 8 equipped with the cam outer shape 5 may be equipped with a roller that follows the helical spiral outer shape of the cam outer shape 5, for example. In this case, the two-armed lever 8 does not complete a pivoting motion around its axis 9, but rather moves upward around an axis in the plane of the drawing, and as a result the other arm 8b completes a downward motion, which can then be transmitted to the adjustment element 10. [Explanation of symbols]

[0035] 1… Electric motor, 2... Output worm, 3… Drive wheel / worm wheel, 4...axis, 5...Cam outer shape, 6…(Recessed part near the axis) 7...Spiral edge, 8...Lever with 2 arms, 8a...First arm, 8b... Second arm, 9…(Intermediate) axis, 10... Adjustment elements, 11... Flexible stopper / clamping means, 12... (Stationary) Stopper, 13… Guide outer shape.

Claims

1. Electric motor (1) and, Interacting with the electric motor (1), the drive wheel (3), particularly the worm wheel (3), has a cam outer shape (5), The lever (8) on which the cam outer shape (5) can be operated, An electric motor drive system for automotive applications, comprising: A flexible stopper (11) is provided so that the drive unit can be decelerated and stopped after the completion of the associated positioning movement. A drive device characterized in that the cam outer shape portion (5) completes a full rotation (360°) in order to act on the lever (8), and is configured such that the cam outer shape portion (5) achieves more than a full rotation (>360°).

2. The drive device according to claim 1, characterized in that the flexible stopper (11) is configured as a clamping means (11) that interacts with the drive wheel (3), in particular the worm wheel (3).

3. The drive device according to claim 2, characterized in that one clamping means (11) is fixed to the drive wheel (3), in particular to the worm wheel (3), and the other is fixed to the stationary stopper (12).

4. The drive device according to claim 3, characterized in that the drive wheel, in particular the worm wheel (3), has a guide outer shape (13) for the clamping means (11).

5. The drive device according to claim 4, characterized in that the guide outer shape portion (13) is provided opposite to the cam outer shape portion (5) on the worm wheel (3).

6. The drive device according to any one of claims 2 to 5, characterized in that the clamping means (11) is a tensioning means designed in the shape of a strip and allows for flexible length changes of 20% or more, preferably 50% or more.

7. The drive device according to claim 6, characterized in that the tensioning means (11) is made entirely or partially from an elastic material, such as an elastomer, a fabric, or a combination thereof.

8. The drive device according to any one of claims 1 to 7, characterized in that the cam outer shape portion (5) has a recess (6) close to the axis on which the worm wheel (3) rotates.

9. The drive device according to claim 8, characterized in that the cam outer shape portion (5) has a helical edge portion (7) that represents two or more full rotations around the shaft (4).

10. An automotive latch, particularly an automotive door latch, characterized by an electric motor drive device according to any one of claims 1 to 9.

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