Safety seal for sealing a conduit in a motor vehicle

Abstract

Safety seal plug 22 for sealing an aperture opening 16, e.g. during an emergency. The seal is normally open during normal operation condition (fig 1), permitting fluid flow. The seal 22 is inflatable

Description

Safety seal for sealing a conduit in a motor vehicle The invention relates to a safety seal which, during an emergency, can seal a conduit in a motor vehicle that is open during normal operation. A radial shaft sealing ring for the permanent sealing of a relatively rotatable shaft is known from DE 10 2008 058 087 A1, in which the radial shaft sealing ring comprises a porous lipophilic coating between two sealing lips which, in case of a leak at one of the sealing lips, is saturated with liquid and increases the contact pressure between the two adjacent sealing lips due to the associated volume increase. Known from DE 3 061 675 A1 is a sealing plug for permanently sealing an opening in a body component of a motor vehicle, in which an expanding sealing material foams out the opening to be sealed due to the effect of heat, and provides a permanent composite by encompassing an edge of the opening. There is a constant need for protecting motor vehicle components against damage. The present invention seeks to present measures that enable effective protection of a motor vehicle component against damage. According to the invention, this may be achieved by means of a safety seal having the claim features. Preferable embodiments of the invention are specified in the dependent claims and the description hereinafter, which in each case can constitute an aspect of the invention individually or in combination. One aspect of the invention relates to a safety seal for, during an emergency, sealing a conduit in a motor vehicle that is open during normal operation, said safety seal comprising a motor vehicle component, the motor vehicle component comprising an opening forming the conduit for exchanging a fluid with an environment, and a sealing body whose volume can be changed as a function of an operational variable, whereby, when the value of the operational variable indicates normal operation, the sealing body at least partially opens the opening and, when the value of the operational variable indicates an emergency, completely fills the opening. In motor vehicle components, a deliberate fluid exchange with an environment can be provided via an opening so that, e.g., a leakage fluid can be discharged or an air cooling of accommodated constructive elements of the motor vehicle component can be performed via natural convection. The conduit provided by the opening therefore enables, e.g., a gravity-driven and / or convective exchange with the environment. This exchange can help to avoid the build-up of harmful substances inside the motor vehicle component and / or the occurrence of damaging heat build-up inside the motor vehicle component. Protection of the motor vehicle component against damage is already provided with the aid of the opening, which enables a fluid exchange with an environment. However, there is a possibility that, if an adjacent component is defective, fluids could enter via the opening and damage the motor vehicle component. There is also the possibility that a defect of the motor vehicle component will still occur due to, e.g., an operating oil leaking through the opening and damaging an adjacent component. It has been found that situations can occur in which the opening, which has a positive effect on operational safety during normal operation, can have a negative effect on operational safety during an emergency. It has also been found that such an emergency typically involves a significant change in an operational variable regarding the environment of the motor vehicle component. For example, a potentially occurring emergency in which the opening of the motor vehicle component can have a negative effect on operational safety is characterised by a change in temperature, a change in pressure, and / or a change in moisture. The material for the sealing body of the safety seal can therefore be selected such that the sealing body can change its volume as a function of an operational variable indicative of an emergency. Doing so leads to a passive safety system that does not have to be actively actuated, but rather reacts automatically to the changing boundary condition that characterises an emergency. During an emergency, the volume of the sealing body can increase, thereby filling and sealing the opening, so that a hazard to operational safety created by the opening can also be avoided during an emergency. Due to the passively triggered volume change of the sealing body when an operational variable indicates an emergency, an additional risk to the operational safety via the opening can be avoided, thus enabling effective protection of a motor vehicle component against damage. In particular, the sealing body is designed such that its volume can be changed reversibly between its volume during normal operation and its volume during an emergency. When there is no longer an emergency, the volume of the sealing body can be reduced, and in particular the sealing body can contract again. Permanent sealing of the opening is thereby avoided so that, after termination of the emergency (e.g., the repair of a defective component triggering the emergency), the opening can be reopened and normal operation can resume. A further repair action for reopening the opening and / or replacing the safety seal is not needed. The operational variable is preferably a temperature, and / or a pressure, and / or a moisture. A different defect of a component that impairs a motor vehicle component typically results in a significant change in such an operational variable. In addition, it is comparatively easy to select a material whose volume can change as a function of such an operational variable and also satisfies requirements for use in a motor vehicle. Particularly preferably, the sealing body is made of a material that expands upon an increase in temperature, and / or a material that expands upon a drop in pressure, and / or a material that swells under the effect of moisture. The sealing body can, e.g., be made of a material having a high coefficient of thermal expansion, in which case the material can have a cross-linked and / or foam-like structure with closed and / or open pores. As a result, the material of the sealing body can expand sharply as the temperature increases, thereby increasing the volume occupied by the sealing body. The sealing body can, e.g., be made of a material with a cross-linked and / or foam- like structure and closed and / or open pores that can be easily compressed under pressure, resulting in a low occupied volume for the sealing body, and can expand back to its starting shape when the pressure drops, resulting in a high occupied volume for the sealing body. The sealing body can, e.g., be made of a material capable of swelling in which, with increasing moisture, a correspondingly large amount of liquid can be accommodated and the sealing body can swell. It is in particular provided that, during an emergency, the sealing body sealingly adjoins an edge of the opening in a circumferential direction with a clamping force, which edge is perpendicular to a surface normal of the opening. Doing so results in a self-reinforcing seal between the sealing body and the edge of the opening. Unintentional separation of the sealing body from the opening can be avoided. In particular, when the opening is provided in a housing wall of the motor vehicle component, the material of the sealing body can protrude from the opening and encompass the edge of the opening, thereby achieving a particularly good seal. Preferably, during normal operation, the sealing body is arranged at least partially within the opening. The sealing body can thereby seal a part of the flow cross- section of the opening, which can have larger dimensions accordingly in order to provide a desired flow cross-section. In general, sufficient construction space is present in a housing wall of the motor vehicle component for this purpose. The flow cross-section remaining in the opening is in particular annular, preferably toroidal. Given that the sealing body already dips into the opening cross-section of the opening during normal operation, only a small distance must be overcome by a volume change of the sealing body in order to seal the opening during an emergency. The safety seal can as a result be correspondingly sensitive and can seal the opening even in case of a comparatively small change in the operational variable. In a further embodiment, during normal operation the entire sealing body is at a distance from the opening along a surface normal of the opening. The flow cross- section of the opening is thereby not impaired by the sealing body, so a correspondingly small and space-saving opening can be provided. In addition, via the distance between the sealing body and the opening, it can be easily adjusted how sensitively the sealing body should react to a change in the operational variable. Not every volume change of the sealing body which occurs during a normal variation of the operational variable leads to a reduction of the flow cross-section of the opening, so the safety seal can be designed to be somewhat more inert and robust. Particularly preferably, the motor vehicle component comprises a housing wall having the opening for accommodating constructive elements of the motor vehicle component, whereby a separately designed retaining element is attached to the housing wall, and the sealing body is attached to the retaining element, whereby, during normal operation the sealing body is positioned along a surface normal of the opening and / or at a distance from the housing wall perpendicular to the surface normal of the opening. The safety seal can thereby be easily retrofitted in case of a motor vehicle component already having an opening. For example, the retaining element can be attached to the outside of the housing wall by means of welding, soldering, or gluing. In particular, the sealing body is made of a material capable of a swelling in the presence of water or an organic solvent. When a moisture content of water or organic solvent increases, the material of the sealing body can swell and seal the opening. Doing so can in particular prevent the penetration of such moisture into the motor vehicle component. The sealing body preferably comprises a gas enclosed in an expandable balloon. The gas in the balloon can expand upon an increase in temperature and / or a drop in pressure, thereby increasing the volume occupied by the balloon and / or by the sealing body. Preferably, the balloon is clad and / or encased by a material capable of swelling. The sealing body can thereby change its volume in response to a plurality of operational variables, in particular temperature, pressure, and / or moisture. As a result, the safety seal can be simultaneously designed for many different emergencies. The invention is explained by way of example hereinafter with reference to the accompanying drawings on the basis of preferred exemplary embodiments, whereby the features presented hereinafter can represent an aspect of the invention both individually and in combination. Shown are: Fig. 1: a schematic cross-sectional view of a first embodiment of a safety seal during normal operation, Fig. 2: a schematic cross-sectional view of the safety seal of Fig. 1 during an emergency, Fig. 3: a schematic cross-sectional view of a second embodiment of a safety seal during normal operation, Fig. 4: a schematic cross-sectional view of the safety seal of Fig. 3 during an emergency, Fig. 5: a schematic cross-sectional view of a third embodiment of a safety seal during normal operation, and Fig. 6: a schematic cross-sectional view of the safety seal of Fig. 5 during an emergency. The safety seal 10 shown in Fig. 1 can be used for a motor vehicle component 12 of a motor vehicle communicating with an environment in order to automatically disrupt, during an emergency, an exchange of gases and / or liquids that is provided between the motor vehicle component 12 and the environment during normal operation. The motor vehicle component 12 comprises, e.g., a housing wall 14, which can accommodate constructive elements of the motor vehicle component 12. The housing wall 14 of the motor vehicle component 12 comprises an opening 16 that forms a conduit for gases and / or liquids. For example, air heated within the motor vehicle component 12 can escape through the opening 16 in order to enable cooling of the constructive elements of the motor vehicle component 12 by natural convection. The opening 16 is formed within a plane of the housing wall 14 and has an opening cross-section with a surface normal 18 extending therefrom in a perpendicular direction. Within an edge 20 that bounds the opening 16, there is an annular sealing body 22 whose insertion depth is bordered by a collar 24 that borders axially on the housing wall 14. If an interference source 26 results in too great of a change in an operational variable 28, then the sealing body 22 can increase its volume to the extent that the opening 16 is filled and sealed by the sealing body 22, as shown in Fig. 2. As a result of its volume increase, the sealing body 22 can press against the edge 20 with a clamping force and enable effective sealing of the sealed opening 16. For example, the operational variable 28 is a moisture resulting from water leakage from the interference source 26, which leads to a swelling of the sealing body 22 in such an emergency, so that the water leakage cannot penetrate the motor vehicle component 12. Not least due to the large free surface of the sealing body 22, the moisture leading to the swelling of the sealing body 22 can vaporise at a later time when the emergency ends and normal operation is restored, whereby the sealing body 22 can reversibly return to its initial state, as shown in Fig. 1. In the embodiment of the safety seal 10 shown in Fig. 3 (as compared to the embodiment of the safety seal 10 shown in Fig. 1), the sealing body 22 is positioned at a distance along the surface normal 18 of the opening 16. For this purpose, a retaining element 30, e.g. designed as a metallic strip, can be fixed to a surface of the housing wall 14 of the motor vehicle component 12. The retaining element 30, which is fixed at one end to the housing wall 14, can have a path that is offset away from the housing wall 14 and, at another end, can be connected to the sealing body 22 on a side facing the housing wall 14 which is positioned opposite the opening 16. As shown in Fig. 4, the sealing body 22 can dip into the opening 16 upon a volume increase caused by the effect of the operational variable 28 and can seal the opening 16. For example, the operational variable 28 is a temperature, so that a gas- filled balloon can expand within the sealing body 22 in case of an increase in temperature in order to seal the opening 16 and protect the constructive elements of the motor vehicle component 12 against overheating. If the heat released by the interference source 26 during an emergency is reduced and normal operation is restored, then the sealing body 22 can reversibly return to its initial state, shown in Fig. 3. In the embodiment of the safety seal 10 shown in Fig. 5 (in comparison to the embodiment of the safety seal 10 shown in Fig. 3) the sealing body 22 is positioned in the opening 16 at a distance from the edge 20 formed by the housing wall 14 of the motor vehicle component 12. In the illustrated exemplary embodiment, the opening 16 is also part of a flow cross-section of a channel that is partially bordered by the housing wall 14 of the motor vehicle component 12 and partially by the retaining element 30 and / or a further component 32. As shown in Fig. 6, the sealing body 22 can seal the opening 16 upon a volume increase caused by the effect of the operational variable 28, thus sealing the cross- sectional flow in the channel. For example, the operational variable 28 is a pressure. For example, during an emergency, the interference source 26 can end a conveyance of liquid through the channel such that a pressure drop occurs in the channel, which triggers a volume increase of the sealing body 22 from a compressed state to a non-compressed state. The sealing body 22 can thereby seal the opening 16, whereby a ventilation and / or a return flow can be avoided. When the emergency has ended and normal operation is restored, the conveyance pressure in the channel can reversibly push and / or compress the sealing body 22 back to its initial state, as shown in Fig. 5.

Claims

Claims 1. A safety seal for, during an emergency, sealing a conduit in a motor vehicle that is open during normal operation, said safety seal comprising a motor vehicle component, wherein the motor vehicle component comprises an opening forming the conduit for exchanging a fluid with an environment, and a sealing body whose volume can be changed as a function of an operational variable, wherein, when the value of the operational variable indicates normal operation, the sealing body at least partially opens the opening and, when the value of the operational variable indicates an emergency, completely fills the opening.

2. The safety seal according to claim 1, wherein the sealing body is designed such that its volume can be changed reversibly between its volume during normal operation and its volume during an emergency.

3. The safety seal according to claim 1 or 2, wherein the operational variable is a temperature, and / or a pressure, and / or a moisture.

4. The safety seal according to any one of claims 1 to 3, wherein the sealing body is made of a material that expands upon an increase in temperature, and / or a material that expands upon a drop in pressure, and / or a material that swells under the effect of moisture.

5. The safety seal according to any one of claims 1 to 4, wherein, during an emergency, the sealing body sealingly adjoins an edge of the opening in a circumferential direction with a clamping force, which edge is perpendicular to a surface normal of the opening.

6. The safety seal according to any one of claims 1 to 5, wherein, during normal operation, the sealing body is arranged at least partially within the opening. / . The safety seal according to any one of claims 1 to 5, wherein, during normal operation, the entire sealing body is at a distance from the opening along a surface normal of the opening.

8. The safety seal according to any one of claims 1 to 7, wherein the motor vehicle component comprises a housing wall having the opening for accommodating constructive elements of the motor vehicle component, wherein a separately designed retaining element is attached to the housing wall, and the sealing body is attached to the retaining element, wherein, during normal operation, the sealing body is positioned along a surface normal of the opening and / or at a distance from the housing wall perpendicular to the surface normal of the opening.

9. The safety seal according to any one of claims 1 to 8, wherein the sealing body is made of a material capable of swelling in the presence of water or an organic solvent.

10. The safety seal according to any one of claims 1 to 9, wherein the sealing body comprises a gas enclosed in an expandable balloon.

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