Flow control mechanism for a motor vehicle

Abstract

Flow guiding mechanism (10) for a motor vehicle, comprising: - a support component (12) - an air passage device (16) adjustable relative to the support component (12) for changing a flow cross-section (Q) in an opening direction (O) and in a closing direction (S) opposite to the opening direction (O), - a normal operation adjusting device (26) which is coupled or can be coupled to the air passage device (16) in a movement-transmitting manner and is designed to adjust the air passage device (16) at least in the opening direction (O), - a control device (34) for controlling the normal operation actuating device (26) and - an emergency operation actuating device (28) with a thermomechanical actuator (29) which is thermally coupled or can be coupled to a predetermined vehicle region (22) and which is designed to, when a temperature (T) of the predetermined vehicle region (22) is higher than a predetermined threshold temperature (T S ), to adjust the air passage device (16) in the opening direction (O) or to hold it in a position in which the flow cross-section (Q) is smaller than in positions of the air passage device (16) at temperatures below the threshold temperature (T S ) is enlarged, characterized in that the thermomechanical actuator (29) of the emergency operation actuating device (28) when the temperature (T) of the predetermined vehicle area (22) is lower than the threshold temperature (T S ) is decoupled from the air passage device (16) in terms of movement and force transmission.

Description

[0001] The present invention relates to a flow guiding mechanism for a motor vehicle, wherein the flow guiding mechanism comprises a support component, an air passage device which is adjustable relative to the support component for changing a flow cross-section in an opening direction and in a closing direction opposite to the opening direction, a normal operation actuating device which is coupled or can be coupled to the air passage device in a movement-transmitting manner and is designed to adjust the air passage device at least in the opening direction, a control device for controlling the normal operation actuating device and an emergency operation actuating device with a thermomechanical actuator which is thermally coupled or can be coupled to a predetermined vehicle region, preferably a vehicle engine or a cooling circuit, and which is designed to then,if a temperature of the predetermined vehicle area is higher than a predetermined threshold temperature, to adjust the air passage device in the opening direction or to hold it in a position in which the flow cross-section is increased compared to positions of the air passage device at temperatures below the threshold temperature.

[0002] In order to protect heat-sensitive components of a motor vehicle, in particular the motor vehicle engine, from overheating, it is known to provide flow guidance mechanisms on such motor vehicles, in particular adjustable air passage devices such as air flaps or blinds, which can be adjusted in the opening and closing direction, for example, by electromechanical actuators such as stepper motors.

[0003] In this case, the flow cross-section through which air can flow through a through opening provided on the support component or the motor vehicle and assigned to the air passage device decreases when the air passage device is adjusted in the closing direction, and the flow cross-section increases when the air passage device is adjusted in the opening direction.

[0004] The control of such air passage devices by electromechanical actuators is known, for example, from DE 10 2005 048 451 A1 and from DE 198 04 427 A1.

[0005] In flow control mechanisms described in the publications DE 32 11 793 A1, DE 20 2005 010 683 U1, DE 34 38 709 C1, and DE 100 26 047 A1, the normal operation control devices each comprise a thermomechanical actuator thermally coupled to the vehicle engine or cooling circuit, such as an expansion element or a bimetallic element. In this way, the air passage device can be adjusted particularly easily depending on the temperature of the predetermined vehicle area to be protected from overheating, without the need for a control unit.

[0006] Finally, a generic flow control mechanism is known from DE 102 18 700 A1. A lever formed from two articulated, interconnected partial levers serves to transmit movement and force from an electromechanical actuator as the normal operation actuating device to the air passage device. A spring, fixed in a preloaded position by a fuse link, is integrated as an emergency operation actuating device. The preloaded spring, locked by the fuse link, bridges the joint of the partial levers, which is also locked by the fuse link.Then, when the temperature of the predetermined vehicle area is higher than the specified threshold temperature, the fusible link melts, releasing the joint for movement, and the spring, which is thus no longer fixed in the pre-tensioned position, drives the partial levers to move relative to their common joint and thus adjusts the air passage device in the opening direction.

[0007] The predetermined threshold temperature can be significantly higher than the usual operating temperatures of the predetermined vehicle area during normal operation and can be selected such that, if the temperature of the vehicle area is below the threshold temperature, no or at least no significant damage to the vehicle area due to overheating is to be expected.

[0008] Such an emergency operation control device ensures that even in the event of a defect in the normal operation control device, the air passage device can be adjusted in the opening direction and thus the predetermined vehicle area can be reliably protected from overheating damage.

[0009] A significant disadvantage of the prior art teaching is that the normal operation control device always moves the thermomechanical actuator of the emergency operation control device when adjusting the air passage device, even during normal operation, and thus must apply a greater force than would be necessary to adjust the air passage device. Therefore, relatively large, heavy, and correspondingly expensive actuators must be used in the normal operation control devices of the known flow guidance mechanisms.

[0010] A further disadvantage of the known flow control mechanism is that once the threshold temperature has been exceeded, neither the normal operation control device nor the emergency operation control device can be operated again without additional repair measures.

[0011] The subsequently published document DE 10 2009 014 003 A1 as well as the documents US 3 265 300 A, DE 37 01 584 A1 and DE 40 20 953 A1 disclose the subject matter of the preamble of claim 1.

[0012] Therefore, the object of the present invention is to further develop the flow guiding mechanism known from the prior art in such a way that in normal operation, i.e. below the predetermined threshold temperature, less force has to be used to adjust the air passage device.

[0013] This object is achieved according to the invention by a flow guiding mechanism according to claim 1. Preferred embodiments of the invention are described in the subclaims.

[0014] To achieve the above-mentioned object, the flow guiding mechanism according to the preamble of claim 1 is designed according to the invention such that the thermomechanical actuator of the emergency operation actuating device is decoupled from the air passage device in terms of movement and force transmission when the temperature of the predetermined vehicle region is lower than the threshold temperature.

[0015] Due to this decoupling, the normal operation control device, which ensures adjustment of the air outlet device under normal operating conditions below the specified threshold temperature, does not have to work against a holding force of the emergency operation control device, nor does it have to move the normal operation control device.

[0016] Such decoupling can be easily achieved by arranging force transmission paths between the normal operation actuating device and the air passage device as well as between the emergency operation actuating device and the air passage device at least partially parallel to each other.

[0017] For example, a common gear can be provided for the transmission of movement and force between the actuating devices and the air passage device, with the power transmission paths between the normal operation actuating device and the gear, as well as between the emergency operation actuating device and the gear, arranged in parallel. Alternatively, actuators of the normal and emergency operation actuating devices can be coupled to the air passage device for movement and force transmission, either directly or via separate gears assigned to the individual actuating devices.

[0018] In principle, it is possible for the normal operation control device and the emergency operation control device to jointly adjust the air passage device when the temperature of the predetermined vehicle area is higher than the specified threshold temperature. However, there is a risk that in this case, at high temperatures, the normal operation and emergency operation control devices will interfere with each other unless the normal operation and emergency operation control devices are set to adjust the air passage device to the same position for temperatures above the threshold temperature. And even if such a setting is initially present, there is a risk that it will be lost over the course of continued vehicle operation and the associated mechanical and other stresses.

[0019] Therefore, it is preferred that the normal operation actuator be decoupled from the air passage device in terms of movement and force transmission when the temperature of the predetermined vehicle area is higher than the predefined threshold temperature. In this case, for temperatures above the threshold temperature, the air passage device is adjusted exclusively by the emergency operation actuator.

[0020] In order to effect this preferred decoupling of the normal operation actuating device from the air passage device, it can be provided that the emergency operation actuating device is designed to decouple the normal operation actuating device from the air passage device in terms of movement and force transmission, at least in the event of a defect in the normal operation actuating device, if the temperature of the predetermined vehicle region exceeds the predetermined threshold temperature.

[0021] In principle, it can be provided that the emergency operation control device destroys a connection such as a connecting web between the normal operation control device and the air passage device, possibly at a predetermined breaking point, when decoupling the normal operation control device from the air passage device. In this case, however, reuse of the normal operation control device is not possible without further repair measures. Such decoupling is particularly useful if, during defect-free normal operation, it is provided that the air passage device is adjusted jointly by the normal operation and emergency operation control devices in the event of temperatures above the threshold temperature, since in this case decoupling of the normal operation control device is only necessary in the event of a defect in this device.

[0022] For flow guidance mechanisms in which the normal operation control device is decoupled from the air guide device in terms of movement and force transmission for temperatures above the threshold temperature, it is preferred that the normal operation control device be able to resume adjustment of the air passage device during normal operation when the predetermined vehicle area has cooled down sufficiently after exceeding the threshold temperature that the temperature falls below the specified threshold temperature again. In this way, the repair measures mentioned above are avoided.

[0023] For example, an actuator of the normal-operation actuating device can be locked directly or indirectly to the air passage device, such as the gearing, in an overridable manner. Additionally or alternatively, the air passage device can be preloaded in the closing direction directly or indirectly via the gearing by a preloading means, such as a spring device. In this case, a mere contact engagement of the normal-operation actuating device with the air passage device can be sufficient, since the normal-operation actuating device, like the emergency-operation actuating device, only needs to provide an adjusting force acting in the opening direction against the preload force of the preloading means. The adjusting force in the closing direction can then be provided by the preloading means.

[0024] Therefore, according to a preferred development of the present invention, the normal operation actuating device is designed to enter into a movement and force transmission coupling with the air passage device when the temperature of the predetermined vehicle region falls below the predetermined threshold temperature.

[0025] It can further be provided that the normal operation actuating device is designed to decouple the emergency operation actuating device from the air passage device in terms of movement and force transmission when the temperature of the predetermined vehicle region exceeds the predetermined threshold temperature.

[0026] In this way, both the normal operation control device and the emergency operation control device can be used repeatedly, even if the specified threshold temperature is exceeded and then undercut several times.

[0027] Preferably, the mechanical actuator of the emergency operation adjusting device may comprise an expansion element or a bimetallic strip, wherein these elements are simple in construction, cost-effective and capable of reliably applying the forces required to adjust the air passage device.

[0028] In the following, the present invention is explained using a preferred embodiment which is shown in the enclosed Fig. 1 to 4.

[0029] They represent: Fig. 1 is a schematic plan view of a flow guiding mechanism of an embodiment of the present invention at a temperature well below the threshold temperature, Fig. 2 the subject of Fig. 1 at a slightly higher temperature, but below the threshold temperature, Fig. 3 the subject of Fig. 1 when the threshold temperature is reached and Fig. 4 the subject of Fig. 3 in case of a defect in the normal operation control device.

[0030] All figures are highly schematic and simplified representations, which are in particular not to scale.

[0031] The one in the Fig. The flow guiding mechanism 10 according to the invention shown in Figures 1 to 4 comprises a support component 12 in the form of a section of a body of a motor vehicle 13 (only indicated) and an air passage device 16 in the form of an air flap 18 arranged in a through opening 14 of the support component 12.

[0032] The air passage device 16 is mounted on the support component 12 so as to be pivotable about an axis 20, so that it can be adjusted in an opening direction O and in a closing direction S, which are indicated in the figures by curved arrows.

[0033] In the present case, due to the symmetrical structure of the air flap 18 with respect to the axis 20, for a flow impinging on the vehicle frontally (in the direction L), the flow cross-section Q of the through-opening 14 is distributed over two equally sized partial flow cross-sections Q / 2.

[0034] If the air flap 18 is moved in the opening direction O, the flow cross-section Q increases, so that, particularly during driving, air can be directed from the surroundings 15 of the vehicle 13 into the vehicle interior 17 to protect a vehicle area 22, indicated only schematically in the figure, from overheating. This vehicle area 22 can be, for example, the vehicle engine.

[0035] The air passage device 16 is in Fig. 1 is shown in a closed position in which the through-opening 14 is largely closed, thus minimizing the flow cross-section Q. It is also possible, although not mandatory, for the flow cross-section to be reduced to zero in the closed position.

[0036] The air passage device 16 can be coupled via a gear 24 to both a normal operation adjusting device 26 and an emergency operation adjusting device 28 in a force and movement-transmitting manner, so that the air flap 18 can be adjusted by both the normal operation adjusting device 26 and the emergency operation adjusting device 28.

[0037] The normal operation actuating device 26 can comprise an electromechanical actuator 30, which converts electrical control signals, which can be output, for example, depending on the detection results of a temperature sensor (not shown) in the vehicle area 22, from a control device 34 connected to the electromechanical actuator 30 via a signal line 32 into an adjustment of a piston rod 36, which acts as the output actuator of the actuator 30. The electromechanical actuator can be, for example, a linear motor or a stepper motor, for example in conjunction with a ball screw drive or the like. Alternatively, pneumatic or hydraulic actuators are also possible.

[0038] The thermomechanical actuator 29 of the emergency operation actuating device 28, which in the present case may be a bimetallic actuator, an expansion element or the like, is thermally coupled to the predetermined vehicle region 22, and in this actuator 28, an adjustment of an associated piston rod 38 takes place according to a temperature of the predetermined vehicle region 22.

[0039] The gear 24, which serves to transmit movement and power from the actuating devices 26, 28 to the air guiding device 16, can in the present case comprise a first lever rod 40 which is pivotally mounted on the vehicle body about an axis 42 running parallel to the axis 20 of the air guiding device 16, and can comprise a connecting rod 44 which is pivotally mounted at two connection points 44a and 44b, one on the first lever rod 40 and the other on the air flap 18.

[0040] The lever rod 40 further has two engagement geometries, in particular engagement openings 46 and 48, into which the piston rods 36 and 38 of the normal operation and emergency operation actuating devices 26, 28 can engage, respectively, in order to establish a coupling between the corresponding actuating device 26, 28 and the gear 24 and thus with the air passage device 16. The force transmission paths between the normal operation actuating device 26 and the air passage device 16, as well as between the emergency operation actuating device 28 and the air passage device 16, up to the gear 24 are functionally parallel to one another.

[0041] The engagement openings 46 and 48 as well as the piston rods 46 and 38 can each comprise locking means (not shown in the figures for reasons of clarity), which engage with each other when the piston rod 36, 38 and the engagement opening 46, 48 are coupled and thus ensure that a movement-transmitting coupling with the gear 24 can be achieved even when the respective piston rod 36, 38 is retracted.

[0042] Alternatively or additionally, the air passage device 16 can also be pre-tensioned in the closing direction S by a spring 45, indicated by dashed lines in the figures, as a pre-tensioning means. In this case, the locking means can be omitted.

[0043] Alternatively, the air passage device 16 can be pre-tensioned in the closing direction indirectly via the gear 24 or directly by pre-tensioning means, so that an adjustment of the air passage device 16 in the opening direction takes place against a pre-tensioning force, which also ensures a return of the air passage device 16 in the closing direction with a corresponding actuator movement.

[0044] The Fig. Figure 1 shows the flow control mechanism in a state in which a temperature T=T1 of the predetermined vehicle region 22 is well below the threshold temperature Ts, and cooling of the vehicle region 22 is therefore not necessary. The air flap 18 is in the closed position.

[0045] In this state, the piston rod 36 of the normal operation actuating device 26 engages the corresponding receiving opening 46 of the lever rod 40. The piston rod 38 of the thermomechanical actuator 29, however, is decoupled from the lever rod 40 and thus also from the air passage device 16 in terms of movement or force transmission.

[0046] At low temperatures, however, it should not be ruled out that the normal operation adjusting device can also be decoupled from the air passage device in terms of movement and force transmission, although as temperatures rise, it must be ensured that a corresponding coupling can be established quickly and reliably in order to be able to adjust the air passage device at least in the opening direction according to the cooling requirements of the vehicle area 22.

[0047] Fig. 2 shows the subject of Fig. 1 at a slightly higher temperature T2, which is still below the threshold temperature T S As the figure shows, both the piston rod 36 of the normal operation actuating device 26 and the piston rod 38 of the emergency operation actuating device 28 are extended further than in the Fig. 1 shown condition.

[0048] The piston rod 36 of the normal operation actuating device 26 thus deflects the lever rod 40 by an angle α counterclockwise from the Fig. 1, which leads to a pivoting of the air flap 18 by an angle β from the position shown in Fig. 1 shown closed position.

[0049] In this position, the flow cross-section Q is significantly larger than in the previously shown closed position and thus significantly more cooling air can reach the predetermined vehicle area 22 and protect it from overheating.

[0050] Even if the piston rod 38 of the emergency operation actuating device 28 is extended significantly further than in Fig. 1, this is not yet sufficient to establish a coupling of the piston rod 38 with the corresponding receiving opening 48 of the lever rod 40, so that the air passage device 16 is controlled exclusively via the normal operation actuating device 26.

[0051] Fig. 3 shows the subject of Fig. 2 when a predetermined threshold temperature T is reached S This is a temperature at which the predetermined vehicle area 22 must be supplied with sufficient cooling air in order to avoid overheating and resulting failure or damage.

[0052] When this temperature is reached, the piston rod 38 of the emergency operation actuating device 28 engages in the corresponding receiving opening 48, so that if the temperature increases further, the air flap 18 can be adjusted further in the opening direction O by the emergency operation actuating device.

[0053] It may be that the Fig. 3 corresponds to the maximum extended state of the piston rod 36, so that upon a further increase in temperature, the piston rod 36 of the normal operation actuating device 26 is pushed out of the receiving opening 46 by the piston rod 38 of the emergency operation actuating device 28 and thus the normal operation actuating device 26 is decoupled from the air passage device 16 in terms of movement and force transmission, so that in this temperature range (T>T S) an adjustment of the air passage device 16 is carried out exclusively by the emergency operation adjusting device 18.

[0054] The flow guide mechanism 10 according to the invention is of particular interest as a fail-safe solution in the event of a defect in the normal operation actuating device 26. As in Fig. 4, even if the normal operation adjusting device 26 is fixed in any position, for example due to a defect, and cannot be moved any further, the air passage device 16 can be reliably adjusted in the opening direction O by the emergency operation adjusting device 28, and thus overheating of the predetermined vehicle area 22 can be reliably prevented.

Claims

[1] Flow guiding mechanism (10) for a motor vehicle, comprising: - a support component (12) - an air passage device (16) adjustable relative to the support component (12) for changing a flow cross-section (Q) in an opening direction (O) and in a closing direction (S) opposite to the opening direction (O), - a normal operation adjusting device (26) which is coupled or can be coupled to the air passage device (16) in a movement-transmitting manner and is designed to adjust the air passage device (16) at least in the opening direction (O), - a control device (34) for controlling the normal operation actuating device (26) and - an emergency operation actuating device (28) with a thermomechanical actuator (29) which is thermally coupled or can be coupled to a predetermined vehicle region (22) and which is designed to, when a temperature (T) of the predetermined vehicle region (22) is higher than a predetermined threshold temperature (T S ), to adjust the air passage device (16) in the opening direction (O) or to hold it in a position in which the flow cross-section (Q) is smaller than in positions of the air passage device (16) at temperatures below the threshold temperature (T S ) is enlarged, characterized by that the thermomechanical actuator (29) of the emergency operation actuating device (28) when the temperature (T) of the predetermined vehicle area (22) is lower than the threshold temperature (T S ) is decoupled from the air passage device (16) in terms of movement and force transmission. [2] Flow guiding mechanism (10) according to claim 1, characterized by that force transmission paths between the normal operation actuating device (26) and the air passage device (16) on the one hand and between the emergency operation actuating device (28) and the air passage device (16) on the other hand are arranged at least partially parallel to one another. [3] Flow guiding mechanism (10) according to one of the preceding claims, characterized by that the normal operation actuating device (26) is decoupled from the air passage device (16) in terms of movement and force transmission when the temperature (T) of the predetermined vehicle region (22) is higher than the predetermined threshold temperature (T S ). [4] Flow guiding mechanism (10) according to one of the preceding claims, in particular according to claim 3, characterized bythat the emergency operation actuating device (28) is designed to decouple the normal operation actuating device (26) from the air passage device (16) in terms of movement and force transmission, at least in the event of a defect in the normal operation actuating device (26), if the temperature (T) of the predetermined vehicle region (22) exceeds the predetermined threshold temperature (T S ) exceeds. [5] Flow guiding mechanism (10) according to claim 3 or 4, characterized by that the normal operation actuating device (26) is designed to enter into a movement and force transmission coupling with the air passage device (16) when the temperature (T) of the predetermined vehicle region (22) exceeds the predetermined threshold temperature (T S ) falls below. [6] Flow guiding mechanism (10) according to one of the preceding claims, characterized bythat the normal operation actuating device (26) is designed to decouple the emergency operation actuating device (28) from the air passage device (16) in terms of movement and force transmission when the temperature (T) of the predetermined vehicle region (22) falls below the predetermined threshold temperature (Ts). [7] Flow guiding mechanism (10) according to one of the preceding claims, characterized by that the thermomechanical actuator (29) comprises an expansion element or a bimetallic strip.

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