Abstract:
A vehicle seat has a cushion integrated in a seat part and/or in a backrest. The cushion has a ventilation layer, through which air can flow, and an air-permeable cushion cover which spans the cushion surface. At least one electrically driven ventilator blows air into the ventilation layer. In order to optimize efficiency and rapidity of seat ventilation when cooling heated seat surfaces and achieve a compact seat construction without any space demands under the cushion of the seat part and behind the cushion of the backrest, the ventilator is constructed such that it takes air in axially and blows air out at least radially and is arranged in the ventilation layer itself. The intake opening of the ventilator is exposed on the side of the cushion facing away from the cushion cover.

Description:
This application claims the priority of German patent application No. 198 04 100.4, filed Feb. 3, 1998, the disclosure of which is expressly incorporated by reference herein. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a vehicle seat having a cushion integrated in a seat part and/or in a backrest. A ventilation layer through which air can flow is provided in the seat part, the backrest, or both the seat part and the backrest, and an air-permeable cushion cover spans the cushion surface facing a sitting person. The seat has at least one electrically driven ventilator for blowing air into the ventilation layer. 
     Ventilated vehicle seats of this type are used for improving a conditioned sitting comfort when a parked vehicle which had been overheated by extended sun radiation is entered and over longer driving periods. 
     In a vehicle seat of this type (German Patent Document DE 196 28 698 C1), a cushion layer or so-called ventilation layer, which consists of a wide-meshed spaced knit and through which air can flow, covers the whole surface of a cushion support made of rubberized hair or foam which rests on a cushion carrier, such as a spring core. The cushion layer is covered on its top or front side facing away from the cushion support by an air-permeable pressure distribution layer made of a spaced knit, nonwoven or open-pore foam. The pressure distribution layer is spanned by a cushion cover, and a cover stuffing is worked in between the cushion cover and the pressure distribution layer. For ventilating the ventilation layer, a plurality of electrically driven miniature fans or miniature ventilators are provided which are inserted into the air ducts worked into the cushion support. These air ducts are arranged to be distributed over the cushion surface. 
     In a limited area above the air duct mouths, an air-impermeable intermediate layer, such as a foil, is in each case arranged on the top side of the ventilation layer facing away from the air duct mouth so that here the air blown by way of the air duct into the ventilation layer does not immediately exit through the pressure distribution layer and the cushion cover but is deflected and flows through the ventilation layer. The miniature fans take in air from the area of the occupant space situated below the seat part and blow this air into the ventilation layer. In the ventilation layer, the air can spread in all directions and, when the seat is unoccupied, flows through the pressure distribution layer and the cushion cover into the air space above the seat surface, causing a rapid cooling of the seat surface heated, for example, by sun radiation. When the seat is occupied, the air flows along in the ventilation layer and exits again at the open ends of the ventilation layer. In the process, it generates a temperature and air humidity gradient and discharges the air moistened by the sitting person. 
     It is an object of the invention to improve, in the case of a vehicle seat of the initially mentioned type, the efficiency and rapidity of the seat ventilation when reducing heated seat surfaces to comfortable temperatures and to permit a structural shape of the vehicle seat which is as compact as possible. 
     In a vehicle seat of the type mentioned above, this object is achieved according to the invention by constructing the ventilator such that it takes air in axially and blows air out at least radially, and by arranging the ventilator in the ventilation layer with an intake opening which is exposed on a side of the cushion facing away from a cushion cover. 
     The vehicle seat according to the invention has the advantage that, because of the direct integration of a ventilator in the ventilation layer which blows at least radially all around, even when the dimensioning of the ventilator is small and its power is low, a sufficiently high air flow rate is achieved in the ventilation layer which cools a cushion heated by sun radiation to comfortable temperatures within a short time when the seat is unoccupied. For cooling of the cushion in the seat part and/or in the backrest, only a few ventilators are required. In an extreme case, only a single ventilator which is arranged in the center of the cushion surface is provided. Furthermore, integration of the ventilator in the ventilation layer, within limits, permits an optional placing of the ventilators so that they can be accommodated better in a cushion zone where the necessary space is available. The space normally required under the cushion for accommodating the ventilators is not required, which is a significant advantage for modern seats because this space is needed for housing so-called anti-submarining wedges or ramps and for electronic and pneumatic automatic seat adjustment systems. 
     According to a preferred embodiment of the invention, the ventilation layer is an air-permeable cushion support which rests on the cushion carrier only by way of an intermediately placed air-impermeable pressure distribution layer. In the pressure distribution layer, an air inflow is constructed which is congruent with the intake opening of the at least one ventilator. By constructing the cushion in this way, a low-cost vehicle seat is achieved which can be used in vehicles of the medium and low price classes. Simultaneously, an extremely compact vehicle seat is created which, in addition, requires no space under the cushion of the seat part or behind the cushion of the backrest. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, the invention is described in detail with reference to embodiments illustrated in the drawing. 
     FIG. 1 is a schematic longitudinal sectional view of a vehicle seat; 
     FIG. 2 is a schematic top view of the seat part of the vehicle seat in FIG. 1; 
     FIG. 3 is the same schematic representation as in FIG. of a modified seat part; and 
     FIG. 4 is a schematic longitudinal sectional view of a seat part of a vehicle seat according to another embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The vehicle seat outlined in FIG. 1 in a schematic longitudinal sectional view, in a known manner, has a seat part  11  adjustably held on the vehicle floor and a backrest  12  which, for adjusting the inclination, is connected with the seat part  11  by way of a swivel locking. The seat part  11  and the backrest  12  each have a cushion  13  which is fastened on a cushion carrier  14 . In the embodiment of FIG. 1, the cushion carrier  14  is constructed as a spring core made of spring wire which is in each case fastened in a frame. In the seat part  11 , the frame has the reference number  15  while, for reasons of clarity, the frame in the backrest  12  was omitted. The cushion  13 , which has the same construction for the seat part  11  as for the backrest  12 , comprises an air-permeable cushion support  16  made of a coarsely structured nonwoven material, such as rubberized hair, or of a spaced knit, and an air-impermeable pressure distribution layer  17  made of a nonwoven or rubberized-hair material of a high density which rests directly on the cushion carrier  14  and completely covers the cushion support  16  on its underside in the seat part  11  and on its back side in the backrest  12 . The top side or front side of the cushion  13 , which faces away from the pressure distribution layer  17 , is covered by an air-permeable cushion cover  18  made of a textile fabric or perforated leather or synthetic material, and a cover stuffing  19  made of cushion padding, nonwoven wool, an open-pore or at least partially perforated foamed material, or a padding-foam combination is worked in between the cushion support  16  and the cushion cover  18 . When an electric seat heater (not shown here in detail) is used, its heating wires are embedded in the cover stuffing  19 . 
     The air-permeable cushion support  16  represents a so-called ventilation layer, through which air can flow by an electrically driven fan or ventilator  20 . The ventilator  20  is constructed such that it takes in axially and blows out radially all around, or radially all around and axially. The ventilator is arranged in the ventilation layer, and thus the air-permeable cushion support  16 , such that its intake opening  201  is exposed on the side of the cushion  13  facing away from the cushion cover  18 . For this purpose, an air inflow opening  21  is provided in the pressure distribution layer  17  and is congruent with the intake opening  201  of the ventilator  20 . The ventilator  20  rests, by way of its intake opening  201 , directly on the air inflow opening  21 , covering it. In the cushion  13  of the backrest  12 , the ventilator  20  is constructed as a radial-flow fan with an axial intake opening  201  and a radial blow-out direction, and in the cushion  13  of the seat part  11 , the ventilator  20  blows to all sides, thus axially as well as radially. The blowing directions of the ventilator  20  are indicated by flow arrows. 
     The ventilator  20  is preferably arranged in the central area of the cushion  13  so that, in the air-permeable cushion support  16  in the seat part  11 , the air flows to the front and to the rear as well as sideways, and in the cushion support  16  of the backrest  12 , the air flows upward as well as downward and also sideways. On the forward and rearward or upper and lower ends as well as the lateral ends of the cushion  13 , the air returns into the vehicle interior. So that the air can exit unhindered from the cushion  13  and therefore a sufficiently high air humidity and temperature gradient with respect to the micro-air-conditioning on the cushion surface is achieved, in order to discharge the transpiration moisture produced by the sitting person from there properly, air outflow openings  22  are provided in the pressure distribution layer  17  on its forward and rearward or upper and lower ends. These air outflow openings  22  also reduce the flow resistance of the cushion support  16  as a whole, so that the efficiency of the seat ventilation is improved. Also, so that when the seat is occupied, the air blown out by the ventilator  20  through the cushion cover  18  will not blow directly at the person sitting in the seat and create unpleasant draft phenomena, in the cushion  13  of the seat part  11 , in which a ventilator  20  is installed with a blowing direction to all sides, thus radially and axially, an air-impermeable blocking layer  23 , such as a foil, is mounted in the area of the axial blow-out opening  202  of the ventilator  20  on the surface of the cushion support  16 . This blocking layer  23  prevents the exiting of air through the cover stuffing  19  and the cushion cover  18  and deflects the axially blown-out air by approximately  900  so that it flows along in the upper edge area of the cushion support  16 . The blocking layer  23  may extend beyond the direct area of the axial blow-out opening  202  and may be at least partially perforated in its course so that different cushion areas are ventilated with different intensities. 
     When the ventilator  20  is constructed as a pure radial-flow fan in the cushion  13  in the backrest  12 , the blocking layer  23  is omitted because the ventilator  20  blows out only radially. However, in order to protect the kidney area of a seat occupant, an identical blocking layer  23  is inserted below the ventilator  20  between the cover stuffing  19  and the cushion support  16  and prevents air from passing through the cushion cover  18  into the kidney area and resulting in draft phenomena there. 
     In the embodiment of the vehicle seat according to FIG. 1, one ventilator  20 , respectively, is disposed in each of the cushions  13  of the seat part  11  and the backrest  12 . These ventilators  20  are arranged approximately in the center in the seat surface and the backrest surface area of the cushion surface. In the cushion  13  of the seat part, the ventilator  20  is arranged close to a quilting  24 . This quilting divides the cushion surface in the seat part  11  into a forward cushion zone  131  and a rearward cushion zone  132  facing the backrest  12 . The ventilator  20  in the cushion  13  of the backrest  12  is arranged slightly below the cushion center. 
     As illustrated in FIG. 3, two ventilators  20  in the cushion  13  of the seat part  11 , which are arranged side-by-side in a transverse spacing viewed in the direction of the seat width, may also be provided for the seat part  11 . An identical arrangement of two ventilators  30  can also be provided in the cushion  13  of the backrest  12 . 
     In a known manner, the backrest  12  is covered on its backside by a backrest covering  25  which is fastened at the lower end of the backrest  12  on the backrest frame and close to the upper end of the backrest  12  on the cushion cover  18 , which for this purpose is pulled over the upper edge of the backrest  12  to the backside of the backrest  12 . Between the backrest covering  25  and the cushion  13  disposed on the cushion carrier  14 , a hollow space exists which is utilized for the guiding of air. The hollow space permits the ventilator  20  in the backrest cushion  13  to take in air from the vehicle interior close to the vehicle floor because here the heating of the interior is the lowest when the vehicle is parked in the sun. For this purpose, an air inlet opening  27  is provided close to the lower end of the backrest  12  in the backrest covering  25 , and the upper air outflow opening  22  in the pressure distribution layer  17 , by way of an air duct  28  which is flexible in the axial direction and which in the embodiment of FIG. 1 is constructed as a bellows, is connected to an outlet opening  29  which is constructed in the area of the cushion cover  18  pulled to the backside of the backrest  12 . 
     When the ventilators  20  are switched on, air is taken in from the vehicle interior by each ventilator  20  by way of the air inlet opening  27  and is blown all around radially and optionally axially into the cushion support  16 . When the seat is unoccupied, the air passes through the air-permeable cover stuffing  19  and the air-permeable cushion cover  18  out into the space above the cushion top surface or front surface. A residual portion of air flows out by way of the air outflow openings  22  in the pressure distribution layer  17  directly, in the case of the seat part  11 , or directly and by way of the air duct  28  and the air outlet opening  29  in the cushion cover  18 , in the case of the backrest  12 , into the vehicle interior. When the seat is occupied, the largest portion of the air blown by the ventilator  20  into the cushion support  16  flows unhindered by way of the air outflow openings  22  in the pressure distribution layer  17  in the case of the seat part  11  directly or, in the case of the backrest  12 , directly and through the air duct  28  and the air outlet opening  29  in the cushion cover  18  out from the cushion support  16 . As a result, a fairly large air humidity and temperature gradient is generated with respect to the micro-air-conditioning on the cushion surface of the cushion  13 , and the transpiration moisture produced by a sitting person is sufficiently discharged by the cushion surface. 
     In the modified seat part  11  of a vehicle seat illustrated as a longitudinal sectional view in FIG. 4, the cushion carrier  14  is constructed as a seat bucket  30  and the air-impermeable pressure distribution layer  17  is constructed as a foam body  31  which is supported on the seat bucket  30 . The air inflow opening  21  and the air outflow openings  22  in the pressure distribution layer  17  are formed by ducts  23  which penetrate the foam body  31  and correspond with openings  32  in the seat bucket  30 . Otherwise, the seat part  11  according to FIG. 4 is constructed in the same manner as the seat part  11  in FIG. 1, so that identical components are provided with the same reference numbers. 
     Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.