Patent Application
20180093696
This document relates generally to the motor vehicle equipment field and, more particularly, to a steering wheel assembly as well as to a heated steering wheel system incorporating that steering wheel assembly.
It is known in the art to equip motor vehicles with heated steering wheels which incorporate a resistive heating element controlled by a thermostat or other controller. Upon reaching a given temperature, the thermostat/controller shuts off power to the resistive heating element in the steering wheel. Heat is then quickly transferred through the steering wheel rim to the interior compartment atmosphere of the motor vehicle.
This document relates to a new and improved steering wheel assembly incorporating a heat sink material between the inner body of the steering wheel assembly and the heating mat of the steering wheel assembly. Advantageously, the heat sink material stores heat from the heating mat and releases it more slowly into the interior compartment atmosphere of the motor vehicle. Advantageously, the new and improved steering wheel assembly disclosed in this document maintains a more consistent steering wheel assembly temperature for added operator comfort while also reducing energy demand.
In accordance with the purposes and benefits described herein, a steering wheel assembly is provided. That steering wheel assembly comprises an inner body, a heat sink material overlying the inner body, a heating mat overlying the heat sink material and an outer wrap overlying the heating mat.
In one or more embodiments, the heat sink material may comprise a single layer of a high thermal conductive material. For purposes of this document “high thermal conductive material” means a material having a thermal conductivity equal to or greater than 204 (W/(m*K°)).
That single layer may be a solid sheet, a mesh or a sprayed mat.
The single layer of thermal conductive material may be constructed from an appropriate metal, an appropriate mineral or an appropriate composite. Appropriate metals include but are not necessarily limited to copper and aluminum. An appropriate mineral includes but is not necessarily limited to diamond, graphite or other carbon materials. Appropriate composites include various metal composites such as copper-tungsten pseudoalloy, aluminum-(silicon carbide) composite, dymalloy, and beryllium oxide in beryllium matrix. In addition, the single layer of high thermal conductive material may comprise a combination of any of the above.
The inner body may comprise polyurethane foam molded around an armature.
In one or more alternative embodiments, the heat sink material may comprise multiple layers of a high thermal conductive material having a thermal conductivity equal to or greater than 204 (W/m*K°). In such an embodiment, at least one of the layers of the multiple layers may be a solid sheet, a mesh or a sprayed mat. Further, at least one of the multiple layers of high thermal conductive material may be selected from a group of materials consisting of a metal, a mineral, a composite, copper, aluminum, diamond, graphite or other carbon material, copper-tungsten pseudoalloy, aluminum-(silicon carbide) composite, dymalloy, beryllium oxide and beryllium matrix and combinations thereof. Further, the inner body may comprise polyurethane foam molded around an armature.
In accordance with yet another aspect, a heated steering wheel system is provided. That heated steering wheel system comprises a steering wheel assembly, a power source and a controller configured to direct power from the power source to the heating mat. The steering wheel assembly includes an inner body, a heat sink material overlying the inner body, a heating mat overlying the heat sink material and an outer wrap overlying the heating mat.
The heat sink material may include at least one layer of a high thermal conductive material having a thermal conductivity equal to or greater than 204 W/(m*K°).
The at least one layer of high thermal conductive material may be selected from a group of materials consisting of a metal, a mineral, a composite, copper, aluminum, diamond, graphite or other carbon material, copper-tungsten pseudoalloy, aluminum-(silicon carbide) composite, dymalloy, beryllium oxide in beryllium matrix and combinations thereof. Further, the inner body may comprise polyurethane foam molded around an armature.
In the following description, there are shown and described several preferred embodiments of the steering wheel assembly and the heated steering wheel system incorporating that steering wheel assembly. As it should be realized, the steering wheel and heated steering wheel system are capable of other, different embodiments and their several details are capable of modification in various, obvious aspects all without departing from the steering wheel and heated steering wheel system as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive.
The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the steering wheel assembly and heated steering wheel system and together with the description serve to explain certain principles thereof. In the drawing figures:
Reference will now be made in detail to the present preferred embodiments of the steering wheel assembly and heated steering wheel system, examples of which are illustrated in the accompanying drawing figures.
Reference is now made to
More specifically, as best shown in
In the embodiment illustrated in
Appropriate composites include but are not necessarily limited to metal matrix composites such as copper-tungsten pseudoalloy, aluminum-(silicon carbide) composite, dymalloy, and beryllium oxide in beryllium matrix. Further, it should be appreciated that the single layer heat sink material 14 may be made of any one of the above materials or any combination of those materials.
More specifically, aluminum-(silicon carbide), also known as AlSiC is a metal matrix composite that consists of aluminum silicon carbide particles held in an aluminum matrix. Aluminum-(silicon carbide) composite has a high thermal conductivity on the order of 180-200 W/(m*K°) that is well-suited for incorporation into the steering wheel assembly 10.
Dymalloy is a metal matrix composite that consists of type I diamond held in an alloy matrix of 20% copper and 80% silver. Dymalloy has a very high thermal conductivity of 420 (W/m*K°) which is also well-suited for incorporation into the steering wheel assembly 10.
In any of the embodiments, the layers 24, 26 of the heat sink material 14 would be processed so that their surfaces are electrically non-conductive but retain their thermal conduction. Further, it should be appreciated that the layers 24, 26 are sandwiched together in a manner that allows thermal conduction in both directions. This allows the heat sink material 14 to store thermal energy or heat delivered to the steering wheel assembly 10 through the heating mat 16 as well as to release thermal energy or heat in a slow and consistent manner when the heating mat 16 is deactivated. In any multiple layer combination, the outer layer of the heat sink material 14 oriented toward the outer wrap 18 may be designed to control the flow of thermal conduction out of the steering wheel assembly 10.
The outer wrap 18 may comprise any appropriate material suited to provide an interface between the steering wheel assembly 10 and the hands of the motor vehicle operator. In one possible embodiment, the outer wrap 18 is made from leather which provides good tactile sensation and conducts a comforting warmth from the steering wheel assembly 10 into the hands of the motor vehicle operator. Of course, other appropriate materials such as alcantara could be utilized for the outer wrap 18.
Reference is now made to
As further illustrated in
When the heated steering wheel system 30 is activated as, for example, by means of the actuator 40 which may comprise a push button or the like, the controller 34 directs power from the power source 32 to the resistance heating element 38 of the heating mat 16. The heating mat 16 then begins to heat the steering wheel assembly 10. Some of that heat or thermal energy is stored in the heat sink material 14 and some of the heat generated by the heating mat 16 is conducted through the outer wrap 18 into the hands of the motor vehicle operator and into the interior atmosphere of the motor vehicle.
Once the heating mat 16 reaches a predetermined temperature, the thermostat 36 provides an appropriate signal to the controller 34 through the control line 42 and the controller deactivates the heating mat 16: that is, interrupts power from the power source 32 to the heating mat 16.
While the heating mat 16 is cycled off, the heat sink material 14 allows slow conduction of the thermal energy stored in the heat sink material 14 outwardly through the outer wrap 18 into the hands of the vehicle operator and the interior atmosphere of the motor vehicle. Advantageously, the heat sink material 14 functions to maintain the outer surface of the outer wrap 18 at a desired operating temperature comfortable to the hands of the motor vehicle operator. The stored thermal energy is conducted slowly so that a more constant temperature is maintained over a longer period of time. Since, the desired temperature is maintained at the surface of the outer wrap 18 for a longer period of time, the timeframe before the heating mat 16 needs to be cycled back on by the controller 34 is extended. Thus, the heat sink material 14 effectively allows the heated steering wheel system 30 to be operated more efficiently, lowering power requirements.
The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.
