WO2019226968A1

WO2019226968A1 - Vehicle seat with cooling and heating using a flexible thermoelectric device

Info

Publication number: WO2019226968A1
Application number: PCT/US2019/033870
Authority: WO
Inventors: Jason R. Davis; Artur STEPANOV; Matthew T. COOK; Eric Kozlowski; Gary Bailey
Original assignee: Magna Seating Inc.
Priority date: 2018-05-25
Filing date: 2019-05-24
Publication date: 2019-11-28

Abstract

A seat assembly includes a foam pad, a flexible substrate, a flexible thermoelectric circuit assembly and a trim cover assembly. The foam pad has at least one air channel. The flexible substrate is mounted on the foam pad. The flexible thermoelectric circuit assembly is mounted on the flexible substrate, and includes a flexible circuit panel and a thermoelectric device. The flexible circuit panel includes a plurality of circuit conductors, and the thermoelectric device is mounted on the flexible circuit panel. The trim cover assembly covers the foam pad, the flexible substrate and the flexible thermoelectric circuit assembly.

Description

VEHICLE SEAT WITH COOLING AND HEATING

USING A FLEXIBLE THERMOELECTRIC DEVICE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional patent application No. 62/676,333, filed May 25, 2018, which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present invention relates to a seat assembly in an automotive vehicle having a heating and cooling mechanism. More particularly, the invention relates to a thermoelectric mechanism for rapidly heating and cooling the surface of the seat assembly for seat occupant comfort.

BACKGROUND OF THE INVENTION

[0003] Automotive vehicles include one or more seat assemblies having a seat cushion and a seat back for supporting a passenger or occupant above a vehicle floor. The seat assembly is commonly mounted to the vehicle floor by a riser assembly. The seat back is typically operatively coupled to the seat cushion by a recliner assembly for providing selective pivotal adjustment of the seat back relative to the seat cushion. Each of the seat cushion and seat back commonly comprise a base foam pad supported by a rigid frame structure and encased in a textile trim cover of cloth, leather, and/or vinyl. The base foam pad provides firm support and durability to the seat cushion and seat back. A trim foam pad, commonly referred to as a plus pad, also is frequently disposed between the base foam pad and the trim cover to provide a softer surface for seat occupant comfort and to improve the appearance of the seat.

[0004] It is commonly known to provide seat assemblies with heating and cooling mechanisms for selectively heating and cooling the surface of the seat for seat occupant comfort. These known heating and cooling

l mechanisms are typically independent mechanisms. For example, it is common to provide an electric wire heating pad between the foam pad and the trim cover of the seat cushion or seat back which is electrically actuated by the power from a vehicle battery to electrically charge the heating pad and provide heat to the surface of the seat cushion or seat back. It is also known to provide fans and air ducts to force cool air through the foam pad and trim cover and provide cool air to the surface of the seat cushion or seat back. It is also known to provide fans and ducts to draw warm, moist air away from the seating surface to provide a gradual cooling effect.

[0005] Current heating and cooling mechanisms, however, require a fair amount of time and power to generate sufficient heat or cool air to affect the temperature of the seat assembly and the desired comfort for the seat occupant. It is desirable, therefore, to provide a heating and cooling mechanism which can rapidly or almost instantly provide heating or cooling to the surface of the seat assembly.

SUMMARY OF THE INVENTION

[0006] According to one embodiment, there is provided a seat assembly comprising a foam pad, a flexible substrate, a flexible thermoelectric circuit assembly and a trim cover assembly. The foam pad has at least one air channel. The flexible substrate is mounted on the foam pad. The flexible thermoelectric circuit assembly is mounted on the flexible substrate, and includes a flexible circuit panel and a thermoelectric device. The flexible circuit panel includes a plurality of circuit conductors, and the thermoelectric device is mounted on the flexible circuit panel. The trim cover assembly covers the foam pad, the flexible substrate and the flexible thermoelectric circuit assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein :

[0008] Figure 1 is a schematic perspective view of a seat assembly for an automotive vehicle;

[0009] Figure 2 is a schematic perspective view of the seat cushion from the seat assembly of Figure 1;

[0010] Figure 3 is a top perspective view of one embodiment of a flexible thermoelectric circuit assembly;

[0011] Figure 4 is a bottom perspective view of the flexible thermoelectric circuit assembly of Figure 3;

[0012] Figure 5 is a top perspective view of a portion of the flexible thermoelectric circuit assembly of Figure 3;

[0013] Figure 6 is a top perspective view of the portion of the flexible thermoelectric circuit assembly of Figure 5 with excess polymer removed;

[0014] Figure 7 is a schematic perspective view of the seat cushion of Figure 2 with the trim cover assembly removed;

[0015] Figure 8 is a schematic perspective view depicting portions of the seat cushion of Figure 7; and

[0016] Figure 9 is a cross-sectional side view of the seat cushion from the seat assembly of Figure 1.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0017] Figure 1 illustrates one embodiment of a seat assembly 10 for use in an automotive vehicle. The seat assembly 10 includes a seat cushion

12 and a seat back 14 operatively coupled to the seat cushion 12 for supporting a seat occupant in a generally upright seating position. The seat back 14 is typically operatively coupled to the seat cushion 12 by a recliner assembly 16 for providing pivotal movement between an upright seating position and a plurality of reclined seating positions.

[0018] Each of the seat cushion 12 and seat back 14 includes a molded resilient cellular foam pad 18 encased in a trim cover assembly 20. The trim cover assembly 20 includes a trim cover 22, commonly of cloth, vinyl, or leather. Seat cooling is particularly desirable in seats with leather trim covers 22 because leather retains more heat than other textiles. The trim cover 22 preferably comprises a chrome free leather, which has a lower heat capacity than standard leather. The trim cover 22 also may comprise leather with increased thermal conductivity as disclosed in U.S. Publication No. 2017/0066355 and U.S. Publication No. 2017/0282767, which are incorporated herein by reference. Increased thermal conductivity decreases the thermal resistance of the leather and will allow a greater heat flux for cooling and heating the seat. Leather trim covers 22 may be perforated or non-perforated. Convection cooled seats typically require perforation for the system to function. The present invention, however, does not require perforation to function properly since it is based on conduction rather than convection.

[0019] The trim cover assembly 20 also includes a plus pad 24 attached to the bottom surface of the trim cover 22. The plus pad 24 may be a traditional foam pad, or it may comprise a plus pad with increased thermal conductivity as disclosed in U.S. Publication No. 2017/0066355, U.S. Publication No. 2018/0290574, U.S. Publication No. 2017/0320245 and WO 2018/175843, each of which is incorporated herein by reference. The increased thermal conductivity decreases the thermal resistance of the plus pad 24 and will allow a greater heat flux for cooling and heating the seat. Lower density plus pads 24 that exhibit greater compression under load are preferred over higher density plus pads 24 that exhibit minimal compression under load because when the seat is occupied, a thinner plus pad 24 reduces the thermal resistance of the plus pad layer. This will allow a greater heat flux for cooling and heating the seat. [0020] Each of the seat cushion 12 and seat back 14 also includes a plurality of thermoelectric devices 26. Preferably, the thermoelectric devices 26 comprise multicouple-based thermoelectric devices as disclosed in International Application No. PCT/US2019/019215, which is incorporated herein by reference. The thermoelectric devices 26 also may comprise unicouple-based thermoelectric devices as disclosed in WO 2018/148398, which also is incorporated herein by reference. The thermoelectric devices 26 may be mounted on a flexible circuit panel 28 to form a flexible thermoelectric circuit assembly 30, as depicted in Figures 3-6. The flexible circuit panel 28 is configured with multiple circuit conductors (not shown) for mounting and connecting the thermoelectric devices 26. When the thermoelectric devices 26 are mounted on a flexible circuit panel 28, excess polymer 32 in areas not containing circuitry may be removed to form a trimmed circuit panel 34. The trimmed circuit panel 34 minimizes audible crinkle sounds when the seat surface is occupied and/or compressed.

[0021] The flexible thermoelectric circuit assembly 30 includes heat sinks 38 mounted to the thermoelectric devices 26. The heat sinks 38 may comprise a variety of thermally conductive materials, such as copper, aluminum or graphite. The heat sinks 38 may be formed via a variety of manufacturing processes. For example the heat sinks 38 may be extruded or stamped, and the fins of the heat sinks 38 may be folded or rolled. Preferably, the heat sinks 38 comprise an extruded aluminum, which is a low- cost, efficient heat sink. Alternatively, the heat sinks 38 may comprise a flexible heat sink as disclosed in U.S. Publication No. 2018/0017334, which is incorporated herein by reference.

[0022] Referring to Figures 7 and 8, since the trimmed circuit panel 34 is irregularly shaped with a number of flexible legs, it is difficult to handle and install onto a vehicle seat. To address this problem, the trimmed circuit panel 34 is mounted on a flexible substrate 36, which joins the legs of the trimmed circuit panel 34 together and stabilizes the assembly. Preferably, the flexible substrate 36 comprises a non-woven fabric. For example, the flexible substrate 36 may comprise a low-cost common seating textile such as Duon^®. Alternatively the flexible substrate 36 may comprise any thin, flexible substrate. Holes and/or slots (not shown) are cut into the flexible substrate 36 so that the flexible thermoelectric circuit assembly 30 is attached to the top of the flexible substrate 36, and the heat sinks 38 extend below the flexible substrate 36. An adhesive or other suitable means is used to attach the flexible thermoelectric circuit assembly 30 to the flexible substrate 36. The flexible substrate 36 may include a peel-and-stick type of adhesive 39 to attach the flexible substrate 36 to the foam pad 18.

[0023] The flexible substrate 36 provides a continuous and uninterrupted surface across the area that it covers, which makes the trimmed circuit panel 34 easier to handle, and improves the assembly process. The flexible substrate 36 also provides a smooth surface for joining the flexible thermoelectric circuit assembly 30 to the foam pad 18, which improves the appearance, comfort and hand feel.

[0024] Referring to Figure 9, the foam pad 18 includes air channels 40 that allow airflow to exhaust heat generated by the thermoelectric devices 26. The depth and width of the air channels 40 and the density and firmness of the foam pad 18 may be customized to obtain the desired balance of airflow, pressure drop and comfort. The foam pad 18 includes air inlet ports 42 and air outlet ports 44. During assembly, the flexible substrate 36 is placed against the upper surface of the foam pad 18 and the heat sinks 38 are placed within the air channels 40. The foam pad 18 is then covered with the trim cover assembly 20.

[0025] The seat assembly 10 includes a blower assembly 46 comprising an air duct 48 and an air mover 50. The air duct 48 has a first end 52 and a second end 54, and the air mover 50 has an air inlet 56 and an air outlet 58. The first end 52 of the air duct 48 is fluidly connected to the air outlet ports 44 of the foam pad 18. The second end 54 of the air duct 48 is fluidly connected to the air inlet 56 of the air mover 50. The blower assembly 46 preferably comprises a centrifugal blower connected to a single duct. A centrifugal blower provides high airflow under various pressure drops while minimizing noise. A single duct 48 connecting all of the air channels 40 to a single air mover 50 minimizes cost. The air duct 48 may be blow molded or injection molded. The first end 52 of the air duct 48 also may be connected to a duct attachment molded to a foam pad 18 as disclosed in WO 2019/014660, which is incorporated herein by reference. Various combinations of air ducts 48 and air movers 50 could be used depending on the needs of the application. For example, the blower assembly 46 may comprise a small tubeaxial fan for each air channel 40. This embodiment would not require any air ducts 48.

[0026] In operation, as depicted in Figure 9, the air mover 50 pulls airflow through the air inlet ports 42, the air channels 40, the air outlet ports 44, and the air duct 48 and exhausts the airflow out of the air outlet 58 of the air mover 50. Alternatively, the airflow direction may be reversed such that the air mover 50 supplies airflow to the air outlet ports 44 and through the air channels 40 (not shown).

[0027] The description above addresses an application in which the invention is used in the seat cushion 12 or seat back 14 of a vehicle seat assembly 10. The invention may also be used in other applications, such as in a vehicle seat bolster, office chairs, couches, sofas, or armchairs. In addition, the cooling/heating capability of a system implementing the present invention may be scaled up or scaled down to tailor to any application by adding or removing cooling/heating components and heat sinks.

[0028] The system uses conductive heat transfer from the flexible thermoelectric device to cool/heat the leather or textile, plus pad and occupant. By directly cooling/heating these components, the system is maximizing efficiency as compared to a convective system which exhausts some of its ability to cool or heat via the air medium used for its convective heat transfer. Another advantage of the present invention is the use of core system components that integrate common design standards. Various cooling/heating systems can be created and used in other applications with minimal validation testing.

[0029] The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims

1. A seat assembly comprising: a foam pad having an air channel; a flexible substrate mounted on the foam pad; a flexible thermoelectric circuit assembly mounted on the flexible substrate, wherein the flexible circuit assembly comprises: a flexible circuit panel comprising a plurality of circuit conductors; and a thermoelectric device mounted on the flexible circuit panel; and a trim cover assembly covering the foam pad, the flexible substrate and the flexible thermoelectric circuit assembly.

2. The seat assembly of claim 1 wherein the flexible thermoelectric circuit assembly further comprises a heat sink coupled to the thermoelectric device, wherein the heat sink is positioned in the air channel of the foam pad.

3. The seat assembly of claim 1 wherein the trim cover assembly comprises a trim cover.

4. The seat assembly of claim 3 wherein the trim cover comprises leather, cloth or vinyl.

5. The seat assembly of claim 4 wherein the trim cover comprises leather with increased thermal conductivity.

6. The seat assembly of claim 3 wherein the trim cover assembly further comprises a plus pad.

7. The seat assembly of claim 6 wherein the plus pad has increased thermal conductivity.

8. The seat assembly of claim 1 further comprising a blower assembly coupled to the foam pad for moving air through the air channel.

9. The seat assembly of claim 8 wherein the blower assembly comprises an air duct coupled to an air mover.

10. The seat assembly of claim 1 wherein the thermoelectric device comprises: a base; and a thermoelectric couple comprising a first thermoelectric element, a second thermoelectric element and a bus bar electrically connecting the first and second thermoelectric element, wherein the first and second thermoelectric elements are set in the base and electrically isolated by the base.

11. The seat assembly of claim 10 wherein the thermoelectric device further comprises: a second base; and a second thermoelectric couple comprising a third thermoelectric element, a fourth thermoelectric element and a second bus bar electrically connecting the third and fourth thermoelectric element, wherein the third and fourth thermoelectric elements are set in the base and electrically isolated from each other and from the first and second thermoelectric element by the base.

12. The seat assembly of claim 1 wherein the flexible substrate comprises a non-woven fabric.