Seat support layer assembly

1. A seat back assembly comprising:

a foam cushion layer;

a support sub-assembly comprising:

a rigid support layer having a plurality of cavities and channels defined on a rear surface for receiving components and a generally smooth front surface;

at least one component retained in one of the cavities, and

a second component secured on the front surface; and

a trim material covering the cushion layer and securing the sub-assembly.

2. The seat back assembly of claim 1 , wherein the rigid support layer is formed of expanded polypropylene (EPP) material.

3. The seat back assembly of claim 1 , wherein an air pump and a controller are mounted in the cavities along the rear surface and an air bladder is secured to the front surface, the air pump, controller and air bladder providing a lumbar support system in the seat back.

4. The seat back assembly of claim 3 , wherein the air pump and controller are retained on the support layer without any fasteners.

5. The seat back assembly of claim 3 , wherein the air pump and controller are retained in the plurality of cavities with an interference fit.

6. The seat back assembly of claim 1 , further comprising a wiring harness retained in a channel defined along the rear surface.

7. The seat back assembly of claim 1 , wherein the sub-assembly is retained in the seat back without any fasteners attached to the support layer.

8. A vehicle seat assembly comprising:

a seat back configured for attachment to a vehicle and having a foam cushion layer defining a seating surface;

a rigid expanded polymer layer disposed adjacent the foam layer, the expanded polymer layer defining at least one cavity on a rear surface and a front surface that abuts the cushion layer;

a lumbar support system including:

an air pump retained in the at least one cavity along the rear surface of the expanded polymer layer; and

at least one air bladder mounted to the front surface of the rigid expanded polymer layer;

a trim material covering the cushion layer and securing the rigid expanded polymer layer to the seat back.

9. The vehicle seat assembly of claim 8 , wherein the rigid expanded polymer layer is formed of expanded polypropylene (EPP) material.

10. The vehicle seat assembly of claim 8 , further comprising at least one air tube routed from the rear surface to the front surface via at least one of a side cut-out and a through hole defined in the rigid expanded polymer layer.

11. The vehicle seat assembly of claim 8 , wherein the air pump is retained in the cavity with an interference fit.

12. The vehicle seat assembly of claim 8 , further comprising a second component retained in a second cavity defined on the rear surface.

13. The vehicle seat assembly of claim 12 , further comprising a wiring harness retained in a channel defined along the rear surface along and connecting at least one of the air pump and the second component.

14. The vehicle seat assembly of claim 8 , wherein the rigid expanded polymer layer is retained in the seat back without any fasteners attached to the rigid expanded polymer layer.

15. A method of manufacturing a seat back:

providing a rigid support layer having a plurality of cavities defined on a rear surface;

forming a sub-assembly by mounting at least one component on the rear surface so the component is retained in one of the cavities without any fasteners;

positioning a cushion layer on the sub-assembly so that that the cushion layer covers at least a front surface of the support layer;

securing a trim material over the cushion layer such that the sub-assembly is retained in the seat back without any fasteners attached to the support layer.

16. The method of claim 15 , further comprising molding the support layer of an expanded polypropylene (EPP) material.

17. The method of claim 15 , further comprising retaining the component in one of the cavities with an interference fit.

18. The method of claim 17 , further comprising retaining the component in one of the cavities with a press-fit.

19. The method of claim 15 , further comprising mounting a lumbar support system on the support layer, wherein an air pump and a controller are mounted in the cavities along the rear surface and an air bladder is secured to the front surface.

20. The method of claim 15 , wherein forming the sub-assembly comprises attaching a wiring harness to the support layer so that the wiring harness is retained in a channel formed on the rear surface.