Setting device for raising the hood of a vehicle

Abstract

Adjustment device (10) for adjusting a hood (100) of a vehicle, comprising a lever mechanism (20) with at least one body connection (22) for rotatable mounting on the body (200) of the vehicle and at least one hood connection (24) for mounting on the hood (100) of the vehicle, further comprising an actuator (30) for introducing an actuator force (AK) via an action lever arm (32) into the lever mechanism (20) for adjusting the hood (100), characterized in that the actuator (30) has a variation section (34) for varying the length of the action lever arm (32).

Description

[0001] The present invention relates to an adjusting device for adjusting the hood of a vehicle according to the preamble of claim 1 and to a method for varying an actuator force in such an adjusting device according to the preamble of claim 8.

[0002] It is known that adjusting devices are used in vehicles to provide active protection in accidents involving pedestrians. For this purpose, sensors detect at low speeds whether a pedestrian is involved in a crash situation near the hood. Based on these or other parameters, an active protection mechanism can be initiated. Known solutions include actively raising the hood to provide a larger crumple zone for impact with a pedestrian's body part. In particular, this can significantly reduce the severity of injuries if a pedestrian's body part hits the hood.

[0003] From DE 10 2013 003 137 A1 and DE 201 06 478 U1 an adjusting device according to the preamble of claim 1 is known.

[0004] DE 10 2013 003 137 A1 discloses a flap for a motor vehicle, which is pivotally mounted on a bearing element on one side and has a locking element on its opposite side for locking the flap in the closed state. The flap is adjustable by means of a drive. The drive is designed as a two-dimensional actuator that enables continuous adjustment of the flap along a first axis and a second axis perpendicular to it within an adjustment range.

[0005] DE 201 06 478 U1 discloses a drive for a flap provided on a motor vehicle. The drive comprises an electric motor, an actuating shaft connected to the flap, a reduction gear through which the rotor of the electric motor is coupled to the actuating shaft, and an energy storage device. The energy storage device can drive the actuating shaft independently of the electric motor. The reduction gear is designed such that the actuating shaft is suddenly driven by the energy storage device in only one direction of rotation, and the electric motor drives the actuating shaft in the opposite direction of rotation, thereby supplying the energy storage device with the energy required to drive the actuating shaft in the direction of rotation. The energy storage device moves the flap suddenly from a basic position to the desired raised position, and the electric motor moves the flap back to its basic or initial position against the resistance of the energy storage device.

[0006] A disadvantage of known solutions is that vibrations can be generated in the hood if the hood is raised very quickly. These vibrations, in turn, have a negative impact on the impact behavior of the pedestrian's body part on the hood. However, to ensure that the hood is raised into the raised position in time in every driving situation, the slowest activation speed must be taken into account when taking temperature into account. Since pyrotechnic solutions are usually preferred to ensure the hood is raised as quickly and safely as possible, the activation speed must be adapted to the slowest temperature situation of such pyrotechnic triggers. This means that the design is for cold outside temperatures, particularly in the range of -20 °C.If such an adjustment device is activated at significantly higher temperatures, for example, in the range of approximately +20 °C, it will trigger significantly faster than at -20 °C. This unnecessarily high speed results from the necessary design of the adjustment device across the entire temperature range in which the vehicle is intended to be used. However, at higher temperature ranges, this leads to the need to accept an undesirably large vibration behavior of the hood during the adjustment movement.

[0007] DE 20 2012 009 477 U1 discloses a vehicle with an engine hood. A hood section, attached to the engine hood, is hinged to an articulated arm by means of a pivot axis. The angle between the articulated arm and the hood section is adjustable by means of a pyrotechnic activator. By changing the angle between the articulated arm and the hood section, the vertical position of the pivot axis can be changed.

[0008] The object of the present invention is to at least partially remedy the disadvantages described above. In particular, the object of the present invention is to reduce vibrations during the adjustment movement of the hood in a cost-effective and simple manner, independent of temperature.

[0009] The above object is achieved by an adjusting device having the features of claim 1 and a method having the features of claim 8. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the adjusting device according to the invention naturally also apply in connection with the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0010] According to the invention, an adjusting device is designed for adjusting the hood of a vehicle. For this purpose, the adjusting device has a lever mechanism with at least one body connection for rotatable mounting on the body of the vehicle. Furthermore, the lever mechanism is equipped with at least one hood connection for mounting on the hood of the vehicle. Furthermore, the adjusting device has an actuator for introducing an actuator force via an acting lever arm into the lever mechanism for adjusting the hood. The actuator, in turn, is equipped with a variation section for varying the length of the acting lever arm.

[0011] According to the invention, an adjusting device is provided for raising the hood in crash situations involving pedestrians. For this purpose, too, it is necessary to perform the raising movement of the hood in very short time periods, in particular in the range of a few microseconds. The actuator can provide the actuator force in a known manner, for example, using a pyrotechnic actuator. The actuator force is not applied directly to the hood, but rather via a lever mechanism, which is supported on the body on one side via the body connection and can transmit the applied actuator force for raising the hood to the body on the other side via the hood connection.

[0012] For the purposes of the present invention, the actual configuration of the lever mechanism, the body connection, and / or the hood connection is irrelevant. Single-joint, double-joint, triple-joint, quadruple-joint, and even multi-joint systems can be used for the lever mechanism, with any desired number of individual lever arms. What is crucial is that the actuator force is introduced into the lever mechanism at a suitable location in order to move the hood from the normal position to a raised position via this lever mechanism.

[0013] The core idea of ​​the invention is that the actuator force is applied via an applied lever arm. This applied lever arm can be provided as an explicit real lever arm, but also as a combination of corresponding components of the actuator and / or the lever mechanism. The applied lever arm refers to the point at which the actuator applies the actuator force to the lever mechanism with reference to the corresponding transfer of this force to the hood. This creates a physically or mechanically effective lever arm, the variation of which influences the actual force effect on the hood. The larger the lever arm, the greater the force applied to the hood. The smaller the lever arm, the smaller the incoming portion of the lever force from the actuator force at the hood.

[0014] According to the invention, it is now possible to vary the length of the lever arm. This indirectly also allows the incoming actuating force on the hood to be varied without having to vary the actuator force. This also makes it possible to use simple and cost-effective actuators, in particular pyrotechnic actuators. Since the actuator force is always the same here, the variation can be achieved via the length of the lever arm. In this way, the actuator can provide a maximum actuator force in the known manner, which, with maximized effect on the hood, ensures the desired opening speed of the hood even at very low temperatures. However, at significantly higher temperatures, this constant actuator force can be physically or mechanically reduced and thus adjusted by varying the length of the lever arm accordingly.This makes it possible to achieve a physical variation in the effect when raising the hood by geometrically adjusting the length of the lever arm.

[0015] In other words, it is possible to vary the hood's opening force depending on temperature while maintaining a constant actuator force. This makes it possible not only to make this system available for modern and new vehicles, but also, in particular, to retrofit existing actuator solutions with the corresponding option for varying the adjustment section.

[0016] It is further advantageous if, in an adjusting device according to the invention, the variation section of the actuator has a motor drive, in particular in the form of a servomotor. This embodiment is combined in particular with a temperature sensor, which directly or indirectly provides information about the temperature of the actuator, the temperature of individual components of the vehicle and / or the outside temperature. Depending on one or more such temperature signals, a motor drive can now provide a variation of the action lever arm. The servomotor can in particular be provided as a stepper motor in order to provide step-by-step adjustment by predefined angular degrees. This can be designed in either a controlled or a regulated manner.

[0017] A further advantage is provided if, in an adjusting device according to the invention, the variation section of the actuator comprises a temperature-sensitive material, in particular a bimetallic material, for an automatic or semi-automatic temperature-dependent variation of the length of the action lever arm. A temperature-sensitive material is understood to be a material that exhibits a mechanical reaction to temperature differences. In particular, this mechanical reaction involves a change in a geometric dimension. Using bimetallic materials, this can be achieved very easily and cost-effectively. This allows, in correlation with the variation section, an automatic effect for varying the length of the action lever arm to be provided. This can be used in combination with the motor drive described above.

[0018] It is further advantageous if, in an adjusting device according to the invention, the variation section is at least partially spiral-shaped, in particular around a variation axis. This is based in particular on a design with a temperature-sensitive or bimetallic material, but can also have spring element sections. Here, too, a combination with a corresponding drive motor is conceivable. The spiral arrangement around a variation axis is provided in particular around an eccentric variation axis according to the following paragraph.

[0019] It may also be advantageous if, in an adjusting device according to the invention, the variation section and / or the actuator has an eccentric bearing for varying the action lever arm by rotating the variation section and / or the actuator about an eccentric variation axis. A rotation solution for the actuator and / or the variation section offers a particularly simple, compact, and cost-effective solution for varying the length of the action lever arm. This is conceivable with a bimetallic solution or with a drive motor, as well as a combination of the two. The connection of the variation axis can also be provided on the body and / or the hood.By means of a simple and, above all, small actuating movement along the eccentric variation axis, it is possible to provide a simple and predefined change in the incoming actuating force on the hood at a constant or essentially constant actuator force.

[0020] It can also be advantageous if, in an adjusting device according to the invention, the actuator is designed as part of the lever mechanism, in particular as part of the body connection. The integration of the actuator into the lever mechanism results in a very compact and space-saving design. This also makes it possible to replace a previously used lever mechanism with a new lever mechanism with an integrated actuator and corresponding variation section, thus providing corresponding retrofitting functionality. In this variant, the actuator and the variation section move with at least part of the lever mechanism during the adjusting movement.

[0021] It is also advantageous if a sensor device is provided in an actuating device according to the invention for determining the temperature for adjusting the actuator and / or the variation section. Such a sensor device has, in particular, one or more temperature sensors, for example, to cooperate with a corresponding motor drive. An at least partial adjustment of the actuator force is also conceivable, for example, in addition to varying the length of the actuating lever arm. Last but not least, when using pyrotechnic actuators, the adjustment of trigger times or other parameters of the pyrotechnic triggering is also conceivable.

[0022] The present invention also relates to a method for varying an actuator force in an adjusting device for adjusting the hood of a vehicle, comprising the following steps: - Determine the current temperature, - Specifying a temperature-specific length for an action lever arm of the adjusting device based on the determined temperature, - Variation of the length of the action lever arm to the specified temperature-specific length.

[0023] In particular, the adjusting device is designed according to the present invention. Thus, a method according to the invention offers the same advantages as those explained in detail with reference to an adjusting device according to the invention. The current temperature can be determined, in particular, by the outside temperature, a material temperature of a vehicle component, and / or the hood temperature and / or the actuator temperature. Of course, different temperatures can also be measured and correlated together to form the starting point for a method according to the invention.

[0024] It is further advantageous if, in a method according to the invention, the variation of the length of the action lever arm is carried out by a driven variation of the variation section. This is therefore an active variation, for example, using a motor drive, for example in the form of a servomotor. This is particularly combined with the use of a corresponding temperature sensor, as already explained.

[0025] Further advantages, features, and details of the invention will become apparent from the following description, which describes embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. They show schematically: Fig. 1 an embodiment of an adjustment system for a bonnet, Fig. 2 an embodiment of an adjusting device according to the invention and Fig. 3 a partial representation of a corresponding actuator.

[0026] Fig. Figure 1 schematically shows how active pedestrian protection can be implemented. This shows a side view of the front of a vehicle. Two large arrows represent the application of an actuator force AK, which here corresponds to the actuating force, which is capable of executing an actuating movement of the bonnet 100. While the bonnet 100 is flush with the outer skin of the vehicle during normal driving, the actuating movement lifts the bonnet 100 from the rest of the body 200. This increases the distance between the bonnet 100 and the engine compartment behind it, and a crumple zone volume is created, which is sprung in particular by actuating components and is capable of reducing the severity of injuries when a pedestrian's body part strikes it. The actuator force AK can be provided, for example, by pyrotechnic actuators 30.

[0027] Fig. Figure 2 schematically shows an embodiment of such an adjusting device 10. This is arranged in particular on both sides of the hood 100, i.e., on both the left and right sides of the vehicle. The adjusting device 10 has a lever mechanism 20 for the main task of adjusting. This lever mechanism 20 is connected to the body 200 via the body connection 22 and is rotatably mounted there. In order to perform a corresponding adjusting movement, the same lever mechanism 20 is mounted on the hood 100 via the hood connection 24. Here, the Fig. 2 is a design as a four-bar system for the lever mechanism 20.

[0028] In order to be able to implement the adjustment movement in a guided manner as quickly as possible, and in particular in preparation for the crash situation, an actuator 30 is provided. This actuator is designed in particular as a pyrotechnic actuator 30 and can introduce the actuator force AK into the lever mechanism 22. This introduction takes place via an acting lever arm 32. Depending on the length of the acting lever arm 32 and the subsequently equipped individual lever kinematics of the lever mechanism 20, an adjustment force is established on the engine hood 100 according to the physical or mechanical properties.

[0029] In order to ensure a variation of the resulting actuating force on the hood 100 with a constant actuator force AK of the actuator 30, the actuator 30 is provided with a variation section 34. This variation section 34 is capable of performing a rotational movement about a variation axis VA, which is arranged eccentrically on the actuator 30. In this way, a change in the acting lever arm 32 can be provided by rotation about this eccentric variation axis VA. If the length of the acting lever arm 32 changes, this leads to a varied resulting actuating force on the hood 100 with a constant actuator force AK.

[0030] While the variation, especially the rotation around the variation axis VA, can generally be provided by a motor drive, automated or semi-automated solutions can also be provided. Fig.3, for example, shows a possibility of providing the variation section 34 with a design using a bimetallic material. A spiral arrangement around the variation axis VA now results in a temperature-specific influence on the spiral design of the variation section 34. The result is an eccentric rotation of the actuator 30 around the variation axis VA, resulting in a mechanical change in the length of the action lever arm 32.

[0031] The above explanation of the embodiments describes the present invention exclusively by way of example. Of course, individual features can be freely combined with one another, provided they are technically feasible, without departing from the scope of the present invention.

Claims

[1] Adjusting device (10) for adjusting a hood (100) of a vehicle, comprising a lever mechanism (20) with at least one body connection (22) for rotatable mounting on the body (200) of the vehicle and at least one hood connection (24) for mounting on the hood (100) of the vehicle, further comprising an actuator (30) for introducing an actuator force (AK) via an action lever arm (32) into the lever mechanism (20) for adjusting the hood (100), characterized by that the actuator (30) has a variation section (34) for varying the length of the action lever arm (32). [2] Adjusting device (10) according to claim 1, characterized by that the variation section (34) of the actuator (30) has a motor drive. [3] Adjusting device (10) according to the previous claim, characterized bythat the variation section (34) of the actuator (30) has a temperature-sensitive material for an automatic or semi-automatic temperature-dependent variation of the length of the action lever arm (32). [4] Adjusting device (10) according to claim 3, characterized by that the variation section (34) is at least partially spiral-shaped. [5] Adjusting device (10) according to one of the preceding claims, characterized by that the variation section (34) and / or the actuator (30) has an eccentric bearing for a variation of the action lever arm (32) by a rotation of the variation section (34) and / or the actuator (30) about an eccentric variation axis (VA). [6] Adjusting device (10) according to one of the preceding claims, characterized by that the actuator (30) is designed as part of the lever mechanism (20). [7] Adjusting device (10) according to one of the preceding claims, characterized by that a sensor device (40) is provided for determining the temperature for adapting the actuator (30) and / or the variation section (34). [8] Method for varying an actuator force (AK) in an adjusting device (10) for adjusting a hood (100) of a vehicle, characterized by the following steps: - Determine the current temperature, - specifying a temperature-specific length for an action lever arm (32) of the adjusting device (10) on the basis of the determined temperature, - Varying the length of the action lever arm (32) to the specified temperature-specific length. [9] Method according to claim 8, characterized by that it is used in an adjusting device (10) having the features of one of claims 1 to 7. [10] Method according to one of claims 8 or 9, characterized bythat the variation of the length of the action lever arm (32) is carried out by a driven variation of a variation section (34).

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