WO2015039701A1

WO2015039701A1 - Massage system for a vehicle seat

Info

Publication number: WO2015039701A1
Application number: PCT/EP2013/069621
Authority: WO
Inventors: Peter ÖBERG; Jari Saren; Daniel Josefsson
Original assignee: Kongsberg Automotive Ab
Priority date: 2013-09-20
Filing date: 2013-09-20
Publication date: 2015-03-26
Also published as: DE112013007448T5; US10369074B2; CN105555599A; DE112013007448B4; US20160213553A1; CN105555599B

Abstract

The present invention provides a massage system for a vehicle seat comprising a plurality of inflatable air cells arranged in a series of subsequent air cells (1, 2, 3), a supply line structure (10, 12; 10a, 12a) from and to each of the plurality of air cells, a pump (14) for supplying air under pressure to the supply line structure, a control or switch unit for controlling the operation of the pump, venting means for venting the supply line structure, means for controlling air flow to and from the air cells to provide a sequential inflation/deflation along said series of air cells, characterized in that said means for controlling air flow are provided by a plurality of flow restrictors (R1, R2, R3) having reduced flow cross-sections, said flow restrictors are arranged in such a manner that between each pair of subsequent air cells (1, 2, 3) in said series of air cells (1, 2, 3) a flow restrictor is disposed in the supply line structure such that the flow resistance from the pump and the venting means to any air cell in said series of air cells (1, 2, 3) is increasing along said series of air cells such that the air cells are inflated in sequence along said series of air cells upon the pump supplying air under pressure to the supply line structure, wherein the flow restrictors are dimensioned such that the delay time between a cell reaching 80% of its volume fill capacity to the next subsequent cell in the series of air cells reaching 80% of its volume fill capacity is between 0,5 s to 30 s, and are deflated in sequence along said series of air cells when venting said supply line structure by said venting means.

Description

Massage system for a vehicle seat

The present invention relates to a massage system for a vehi^¬ cle seat comprising a plurality of inflatable air cells ar^¬ ranged in a series of subsequent air cells, a supply line structure having a connection for fluid communication from and to each of the plurality of air cells in said series, a pump for supplying air under pressure to the supply line struc^¬ ture, a control or switch unit for controlling the operation of the pump, venting means for venting the supply line struc^¬ ture, means for controlling air flow to and from the air cells to provide a sequential inflation/deflation along said series of air cells.

Drivers and passengers of motor vehicles, especially when driving long distances, often experience discomforts caused by long time static posture when seated in a vehicle seat. This is not only felt as being uncomfortable and causing for exam^¬ ple back pain but may also lead to permanent impairment of health, in particular for professional drivers such as taxi, truck and bus drivers. To provide a remedy the automotive in^¬ dustry since some time offers vehicle seats with integrated massage systems in the seat back.

Such a massage system is for example disclosed in US 5,135,282 A which forms the basis for the preamble of claim 1. A series of inflatable air cells is disposed along the seat back close to the inner surface of the seat back cover. A supply line structure is receiving compressed air from a pump and is sup^¬ plying this compressed air to the air cells for sequentially inflating/deflating the series of air cells. For this purpose the supply line structure comprises a common supply line in^¬ terconnecting the air cells in series, and an exhaust or vent^¬ ing line interconnecting the series of air cells, which vent- ing line is capable of being opened to the environment for venting in order to deflate the air cells. In order to produce a propagating sequential inflation along said series of the air cells starting from the first cell at the lower end of the seat back and continuing cell by cell to the last cell at the upper end of the seat back, a number of controllable valves and a control unit are provided. In particular, there is a valve at the beginning of the supply line upstream of the first cell, and a controllable valve between each pair of ad^¬ jacent cells along said series of air cells. In order to ini^¬ tiate an inflation cycle the control or switch unit starts the pump to deliver air and opens the first valve in the supply line upstream of the first air cell while keeping the remain^¬ ing valves in a closed state such that the first cell is in^¬ flated. The control unit is arranged to open the remaining valves along said series of air cells sequentially such that, after the first air cell has been inflated, the valve upstream of the second air cell is opened to inflate the second air cell, thereafter the valve upstream of the third cell is opened etc. until all air cells along said series of air cells are inflated. After all air cells of said series of air cells have been inflated the control unit stops the pump and the venting line in a corresponding manner sequentially to deflate the air cells in said series of air cells in sequence, again starting with the first air cell, and than continuously by cell through that series of air cells until all cells are de^¬ flated .

This massage system for a vehicle seat is rather complicated because of the rather large number of controllable valves, namely 2n + 2 valves for a series of n air cells. This implies rather high costs for the valves themselves and for the rather complicated assembly process including the provision of a con^¬ nection between each of the valves and the control unit. It is therefore an object of the present invention to provide a massage system for a vehicle seat which is simple in its de^¬ sign and assembly and which requires less controllable compo^¬ nent to simplify the assembly process and to reduce costs.

This object is archived by a massage system comprising the features of claim 1. Preferred embodiments are set out in the dependent claims.

According to the present invention the supply line structure is provided with a plurality of flow restrictors, i.e. passive elements of substantially increased flow resistance compared to the remaining supply line structure. Such flow restrictors can for example be realized by line segments of decreased cross-sectional area, e.g. segments with passageways of re^¬ duced diameter. The flow restrictors are arranged in the sup^¬ ply line structure in such a manner that between each pair of subsequent air cells in a series of air cells a flow restric- tor is disposed such that the flow resistance from the pump and the venting means to any air cell in that series of air cells is increasing along said series of air cells such that the air cells are inflated in sequence along said series of air cells upon the pump supplying air under pressure to the supply line structure. The flow restrictors are dimensioned such that the delay time between a cell reaching 80% of its volume fill capacity to the next subsequent cell in the series of air cells reaching 80% of its volume fill capacity is be^¬ tween 0,5 seconds to 30 seconds, preferably 0,5 to 10 sec^¬ onds. In a corresponding manner the flow restrictors ensure that the air cells are deflated in sequence along said series of air cells when venting said supply lines structure by said venting means.

In connection with the present invention it has been found that the feeling and effect of a sequentially propagating in- flation along a series of air cells can already be achieved when the delay time between subsequent air cells reaching 80% of there filling volume is between 0,5 seconds to 30 seconds. It is not necessary that a particular cell is already fully inflated, when the next cell starts to be filled. In particu^¬ lar it has been found that the feeling and effect of a propa^¬ gating sequential inflation is sufficiently achieved by con^¬ trolling the delay time between the 80% filling states.

With the arrangement of the present invention no valves are needed but the sequential inflation can be achieved with the flow restrictors between subsequent air cells in the supply line structure. The omission of any valves simplifies the as^¬ sembly procedure and significantly reduces the costs of the massage system since passive flow restrictor are much less ex^¬ pensive than valves; in addition, there is no need to connect any controllable valve to a central control unit which simpli^¬ fies the assembly process and thus also reduces the costs of the massage system. Simplified tube routing simplifies not only installation, but also packaging and over all space requirement for the massage function. In order to achieve the defined delay time between the filling of subsequent air cells the flow restrictors have to be properly dimensioned in de^¬ pendence on the pump capacity, the remaining flow restrictors in the supply line structure, and the architecture of supply line structure. Further below, a large number of examples will be given for flow restrictor dimensions in particular series of air cells and particular supply line structures.

In a preferred embodiment the supply line structure comprises a supply line to which each of the air cells in said series of air cells is connected. A flow restrictor is disposed in the supply line between each pair of subsequent air cells such that the flow resistance along the supply line is increasing with each flow resistor arranged in series along the supply line. Such arrangement is referred to as serial arrangement in the following.

Alternatively the supply line structure comprises a supply line and connection lines, each connection line connecting the supply line to an air cell in said series of air cells. In such arrangement a flow resistor can be disposed in each connection line to an individual air cell. Such arrangement is referred to as parallel arrangement in the following in which the flow resistant to an individual air cell is mainly deter^¬ mined by the flow restrictor associated with this air cell in its connection line to the supply line.

In a preferred embodiment a valve is disposed in the supply line structure between the pump and said series of air cells, wherein said valve is operable by the control or switch unit to be switched between a state in which the fluid connection between the pump and said series of air cells is open and an opening to the environment is closed, and a state in which the opening to the environment is opened for venting the supply line structure.

In an alternative arrangement there is no valve in the supply line structure. In such embodiment the venting means are pro^¬ vided by an opening equipped with a venting flow restrictor which is permanently open to the environment so that there is a continuous venting flow to the environment during operation of the massage system, wherein the venting flow restrictor and the pump are arranged such that the pump is capable of provid^¬ ing sufficient air flow to inflate the series of air cells while at the same time air is leaking through the venting flow restrictor. After termination of the operation of the pump the air cells and in said series of air cell will sequentially de^¬ flate by venting the supply line structure through the flow restrictor in the venting opening. In a preferred embodiment the first flow restrictor downstream of the pump and upstream of the first air cell has a through- going passage of an effective inner diameter of 0,4 to 2 mm (the diameter is referred to as an effective inner diameter because the throughgoing passage does not necessarily have to be cylindrical but could for example also have a rectangular or square cross-section; the effective diameter is then the diameter of a cylindrical passageway having the same cross- sectional area) . The second flow resistor upstream of the sec^¬ ond air cell then has an effective inner diameter of 5 - 80% of the diameter of the first flow resistor. The third flow re^¬ sistor upstream of a third cell in said series of air cell has an effective inner diameter in the range of 10 - 100% of the diameter of the second flow resistor. In particular, it is preferred that the first flow resistor upstream of the first cell has an effective inner diameter of 0,5 - 1,5 mm, the sec^¬ ond flow resistor upstream of a second cell has an inner diameter of 10 - 30% of the diameter of the first flow resistor, and the third flow resistor upstream of a third cell and said series of air cells has an effective inner diameter of 50 - 80% of the diameter of the second resistor. In typical embodi^¬ ments the flow restrictors will have reduced diameter passage ways of a length in the range 0,4 - 10 mm, for example 5 mm.

The flow through a tube is according to the Hagen Poiseuille equation proportional to the fourth power of the radius and to the reciprocal length of the tube. As known to the skilled person this can be used together with other variables as the pump output rate to vary the dimensions of the flow restric^¬ tors to achieve the desired flow pattern. The diameter of the supply lines is significantly larger that that of the flow re^¬ strictors . In a preferred embodiment a second series of air cells is con^¬ nected to the supply line structure in a symmetrical manner to the first series of air cells.

The invention will be described in the following in connection with various examples of preferred arrangements in the draw^¬ ings, in which

Fig. la - lj show schematical perspective views of a serial air cell arrangement during subsequent steps of an infla^¬ tion/deflation cycle;

Fig. 2 shows a schematical block diagram of a massage system according to a first embodiment,

Fig. 3 shows a graph of sequential inflation and deflation of the series of cells of the embodiment of Fig. 2,

Fig. 4 shows a schematical block diagram of a massage system according to a second embodiment,

Fig. 5 shows a graph of subsequent inflation and deflation of the series of cells of the embodiment of Fig. 4,

Fig. 6 shows a schematical block diagram of a massage system according to a third embodiment,

Fig. 7 shows a graph of sequential inflation and deflation of the series of cells of the embodiment of Fig. 6,

Fig. 8 shows a schematical block diagram of a massage system according to a fourth embodiment,

Fig. 9 shows a graph of sequential inflation and deflation of the series of cells of the embodiment of Fig. 8, Fig. 10 shows a schematical block diagram of a massage system according to a fifth embodiment,

Fig. 11 shows a schematical block diagram of a massage system according to a sixth embodiment,

Fig. 12 shows a schematical block diagram of a massage system according to a seventh embodiment,

Fig. 13 shows a schematical block diagram of a massage system according to an eighth embodiment,

Fig. 10 shows a schematical block diagram of a massage system according to a ninth embodiment,

Fig. 14 shows a schematical block diagram of a massage system according to a tenth embodiment,

Fig. 15 shows a schematical block diagram of a massage system according to a eleventh embodiment,

Fig. 16 shows a schematical block diagram of a massage system according to a twelfth embodiment,

Fig. 17 shows a schematical block diagram of a massage system according to a thirteenth embodiment,

Fig. 18 shows a schematical block diagram of a massage system according to a fifteenth embodiment.

In Fig. la a schematical perspective view of a massage system is shown which has a first series of three air cells 1, 2, and 3 connected to a common supply line 10 by connection lines 12. In a symmetrical manner a second series of air cells 1', 2', and 3' is connected to the common supply line 10. A pump (not shown) is used to supply compressed air to the supply line 10.

Between each pair 1, 2 and 2, 3 of subsequent air cells a flow restrictor Rl and R2 respectively, is disposed. The same ap^¬ plies to the second series of air cells 1', 2' and 3'.

In the initial state la the pump has not yet been activated, and all air cells 1, 2, 3, 1', 2', 3' are fully deflated. In Fig. lb the pump has started to supply compressed air, and the first air cells 1, 1' in the two parallel series of air cells start to be inflated. Due to the flow restrictors the infla^¬ tion of the air cell starts in the first air cell 1 (and 1' for the second series of air cells), whereas the pressure for the second air cells 2, 2' in said series of air cells has not yet sufficiently built up.

In Fig. lc the first air cells 1 and 1' are already filled to a large extent, whereas the second air cells 2 and 2' are still in the initial phase of inflation. At this stage the pressure at the third air cells 3 and 3' has not yet suffi^¬ ciently built up to cause any notable inflation.

In Fig. Id the first air cells 1 and 1' are fully inflated, the second air cells are already inflated to a large extent, and the third air cells 3 and 3' are in the state of being in^¬ flated .

In Fig. le the first air cells 1 and 1' and the second air cells 2 and 2' are fully inflated, and the third air cells 3 and 3' are close to reaching the fully inflated state.

In Fig. If pressure supply from the pump has been terminated, and venting means for venting the supply line structure 10, 12 have been opened, so that the first air cells 1 and 1' are al- ready starting to deflate (the venting means (not shown) are located at the lower end of the series so that air is vented off through the lower end of the common supply line 10) .

In Fig. lg deflation of the first cells 1 and 1' has continued further, and deflation of the second cells 2 and 2' has started .

In Fig. lh the first air cells 1 and 1' are already fully de^¬ flated, the second air cells 2 and 2' continue to deflate, and the third air cells 3 and 3' start to deflate.

In Fig. li also the second air cells 2 and 2' have reached the fully deflated state, while the third air cells 3 and 3' still continue to deflate. Finally in Fig. lj also the third air cells 3 and 3' are fully deflated to complete one infla^¬ tion/deflation cycle in Fig. la - lj.

In the following various arrangements of massage systems will described with details of the dimensioning of the flow re- strictors in connection with pump capacities and air cell pa^¬ rameters .

The air cells have a base area of 60 x 50 mm. In the deflated state the side walls are collapsed. During inflation the side walls are raised and reach a height of 50 mm in the fully in^¬ flated state. The state of inflation may also be expressed as a fill height of the air cells which refers to the height to which the side walls have already been raised from the col^¬ lapsed state of a deflated cell. The fill height of the cell is thus zero for a fully deflated cell, and is 50 mm for a fully inflated cell in this example.

In the following example the air cell walls are made of poly- urethane foil having a thickness of 0,5 mm. In principle, also other plastic materials or even fabrics could be used to form the air cells. Also other foil thicknesses than 0,5 mm, for example 0,375 mm or 0,7 mm could be used.

Fig. 2 shows an example with a supply line structure with a serial arrangement of flow resistors Rl, R2 and R3 along two parallel series of air cells 1, 2, 3, and 1', 2', and 3', re^¬ spectively. In the first example, the pump is adjusted to pro^¬ vide air at the rate of 5 1/min. A valve 16 is provided which can be switched between a state in which it provides fluid connection between the pump 14 and the common supply line 10, and a state in which it opens the common supply line to the environment for venting. There is a first series of air cells 1, 2 and 3, and a second series of air cells 1', 2' and 3'. The air cells have the above described dimensions of 60 x 50 x 50 mm, and are made of polyurethane foil of 0,5 mm thickness.

The first flow restrictor Rl upstream of the first air cells 1 and 1' has an effective inner diameter of 0,9 mm. The second restrictor R2 downstream of the first and upstream of the second air cells 2 and 2' has an effective inner diameter of 0,5 mm. The third restrictor R3 downstream of the second air cells 2 and 2' and upstream of third air cells 3 and 3' has an ef^¬ fective inner diameter of 0,4 mm. The flow restrictors in this and all following examples have a length in flow direction of 5 mm. This arrangement and dimensioning of the flow restric^¬ tors Rl, R2 and R3 is suitable for providing the desired delay in the inflation/deflation circle between subsequent air cells in said series of air cells.

An inflation/deflation cycle is initiated by starting pump 14 and switching valve 16 to a first state in which there is fluid communication between the pump 14 and the common supply line 10 and in which the supply line 10 is not opened to the environment. In Fig. 3 the resulting delay in the inflation of subsequent air cells 1, 2 and 3, and 1', 2' and 3', respec^¬ tively, is shown as the cell fill height as a function of time during an inflation/deflation cycle. It can be seen that the delay time between cell 1 and cell 2 reaching 80% of the fill height is about 1,5 seconds. In the arrangement of Fig. 2 the flow resistance upstream of the third cell 3 and 3', respec^¬ tively is substantially increased by flow restrictor R3 so that there is a delay time of about four seconds between the second and third cells 2 and 3 reaching the 80% filling height state .

Fig. 4 shows a further example which is identical to the first example of Fig. 2 except that the pump supplies air at an in^¬ creased flow rate of 6,5 1/min compared to 5,0 1/min in the example of Fig. 2. Fig. 5 shows the resulting graph showing the fill state of the air cells as a function of time during an inflation/deflation cycle. As expected the increased air supply slightly reduces the delay times between the subsequent cells until they reach 80% of their filling capacity.

Fig. 6 shows a third example. As in the first and second exam^¬ ple Fig. 6 shows two parallel series of air cells 1, 2, and 3, and 1', 2', and 3', respectively, connected by a common supply line 10 in which flow restrictors Rl, R2 and R3 are disposed in a serial configuration so that each flow resistor adds up to the total flow resistance to the air cell downstream of the flow restrictor. In this example there is a leakage opening in the supply line in which a further flow restrictor R4 is disposed. If such opening in the supply line to the environment is provided there is a permanent leakage flow during inflation and deflation. This leakage flow to the environment can also be utilized for venting the supply line structure for defla^¬ tion. In this case the valve 16 could in principle be omitted, and there could be a permanent connection between the pump 14 and the supply line. In this example the pump 14 is adjusted to provide air at a rate of 6,5 1/min. The subsequent flow re- strictors have the indicated effective inner diameters. Fig. 7 shows the graph of the corresponding filling state of the air cells as a function of time during an inflation/deflation cycle. As can be seen from this graph there is a delay time of about 4 seconds between the first cell 1 and the second cell 2, and a delay time of about two seconds between the second cell 2 and the third cell 3.

Fig. 8 shows again a serial arrangement of resistors Rl, R2, and R3 which two parallel series of air cells as in the third example of Fig. 6. The flow restrictor dimensions are also the same as in the third example of Fig. 6. The only difference with respect to the third example is that there is no venting opening with a flow restrictor in the common supply line 10. Fig. 9 shows the resulting graph of the fill state of the cells as a function of time during an inflation/deflation cycle. In comparison with Fig. 7 it can be seen that all air cells reach the 80% inflated state and the fully inflated state more quickly which is due to the fact that there is no leakage flow as there was through flow restrictor R4 in the third example of Fig. 6. Also the delay times between cells 1 and 2, and 2 and 3 are slightly reduced.

Fig. 10 and Fig. 11 again show serial arrangements of flow re- strictors Rl, R2 and R3 along the common supply line for a system with two parallel series of air cells 1, 2 and 3, and 1', 2', and 3', respectively. In Fig. 11, compared to the ex^¬ ample of Fig. 10, the flow restrictor Rl has a slightly enlarged diameter of 1,0 mm. Also the remaining flow restric- tors have increased inner diameters, namely, 0,7 mm for flow restrictor R2, and 0,5 mm for flow restrictor R3. At the same time the pump has been adjusted to supply less than 5 1/min. so that the inflation/deflation along the series of air cells is still similar as in the example of Fig. 10 since the lower volume rate of the pump in Fig. 11 is largely compensated by the increased inner diameters of the flow restrictors Rl, R2 and R3.

Fig. 12 shows a further example of a serial arrangement of flow resistors along the common supply line with two parallel series of air cells 1, 2, and 3, and 1', 2', and 3', respec^¬ tively, being connected to the common supply line 10. In this example there is no flow restrictor in the common supply line 10 upstream of the first cells 1 and 1' which leads to a rather fast inflation of the first cells 1 and 1'. The common supply line 10 has a leakage opening in which a further flow restrictor R4 is located which causes permanent leakage during inflation and venting during deflation. Since the venting during deflation could proceed also through flow resistor R4, the valve 16 could also be omitted.

Fig. 13 shows a further example with a serial arrangement of flow restrictors Rl and R4 in the supply line 10a, and further parallel flow restrictors R2 and R3 in the connecting line to the first air cell 1 and the second air cell 2, respectively. As indicated, flow restrictor R2 has a larger inner diameter than the parallel flow restrictor R3 upstream of the second cell 2 so that the desired delay time between the first cell 1 and the second air cell 2 is achieve. The inflation of the third air cell 3 in the series of air cells is delayed by the flow restrictor R4 of even smaller inner diameter.

Fig. 14 shows an example of a massage system with a common supply line 10 with serial arrangement of flow restrictors and a first series of subsequent air cells 1, 2, ... n. A second parallel series of air cells is indicated by dotted lines as an option. Along the series of air cells 1, 2, ... n the flow resistance to the particular cell from the pump 14 is increas^¬ ing cell by cell by each further flow restrictor in the common supply line 10. In addition this increase along the series of air cell can be made steeper by decreasing the inner diameter of the flow restrictors along the series of air cells.

Fig. 15 shows an example of two parallel series of air cells 1, 2, and 3, and 1', 2', and 3', respectively; this time the flow restrictors R2, R3, R4 are arranged in parallel so that the effect of the flow restrictors R2, R3, R4 and R2 ' , R3 ' , and R4 ' is limited to the associated air cell. In addition there is a common inlet flow restrictor Rl in the common supply line 10a; in this Fig. the subsequent parallel flow re^¬ strictors R2, R3 and R4 are indicated with the same inner di^¬ ameter for simplification purposes, whereas R2 indeed has a smaller diameter than Rl, and R3 a still smaller diameter.

Fig. 16 shows a further configuration with two parallel series of air cells 1, 2, and 3, and 1', 2', and 3', respectively, and flow restrictors R3, R4 and R5 arranged in series in the common supply line 10. A further pair of air cells 4 and 4' is added at the other side to the common supply line 10. If the flow restrictor R3 upstream of the first cells 1 and 1', and the flow restrictor R2 upstream of the further pair of air cells 4 and 4' are of the same dimensions the inflation of the air cells 1, 1' and 4, 4' would be almost simultaneous, wherein the inflation in air cells 4, 4' being a little bit faster since pressure builds up faster in this branch of the supply line 10 because no air is flowing of to further pairs of air cells downstream of cells 4, 4'.

Fig. 17 shows an example of two parallel series of air cells 1 and 2, and 1' and 2', respectively, wherein there are two flow restrictors Rl and R3 disposed in series along the common sup^¬ ply line, and two flow restrictors R2 and R4 are arranged in parallel in the connecting lines, to the associated air cells 1' and 2, respectively. These further restrictors R2 and R4 will result in an imbalance between the two series of air cells 1 and 2, and 1' and 2' which leads to asymmetrical in^¬ flation/deflation cycle in the two series of air cells.

Fig. 18 shows a further example of a system with two parallel series of air cells 1, 2, and 3, and 1', 2', and 3', respec^¬ tively connected to common supply line 10 in which flow re- strictors Rl, R2, R3 and R4 are arranged in a series along the common supply line 10. In this example the flow restrictors are integrated into the X pieces which form the connections between the common supply line and the two connected air cells of the two parallel series of air cells.

Claims

1. A massage system for a vehicle seat comprising a plurality of inflatable air cells arranged in a series of subsequent air cells (1, 2, 3), a supply line structure (10, 12; 10a, 12a) having a con^¬ nection for fluid communication from and to each of the plurality of air cells in said series, a pump (14) for supplying air under pressure to the supply line structure, a control unit or switch for controlling the operation of the pump, venting means for venting the supply line structure, means for controlling air flow to and from the air cells to provide a sequential inflation/deflation along said se^¬ ries of air cells, characterized in that said means for controlling air flow are provided by a plurality of flow restrictors (Rl, R2, R3 ) having reduced flow cross-sections, said flow restric^¬ tors are arranged in such a manner that between each pair of subsequent air cells (1, 2, 3) in said series of air cells (1, 2, 3) a flow restrictor is disposed in the sup^¬ ply line structure such that the flow resistance from the pump and the venting means to any air cell in said series of air cells (1, 2, 3) is increasing along said series of air cells such that the air cells are inflated in sequence along said series of air cells upon the pump supplying air under pressure to the supply line structure, wherein the flow restrictors are dimensioned such that the delay time between a cell reaching 80% of its volume fill capacity to the next subsequent cell in the series of air cells reach^¬ ing 80% of its volume fill capacity is between 0,5 s to 30 s, and are deflated in sequence along said series of air cells when venting said supply line structure by said venting means.

2. The massage system for a vehicle seat according to claim 1, characterized in that the supply line structure (10, 12) comprises a supply line (10) to which each of the air cells in said series of air cells (1, 2, 3) is connected, wherein the flow restrictors (Rl, R2, R3 ) are disposed in the supply line between subsequent air cells such that the flow resistance along the supply line is increasing with each flow resistor arranged in series along the supply line (10) between subsequent air cells.

3. The massage system for a vehicle seat according to claim 1, characterized in that the supply line structure com^¬ prises a supply line (10a) and connection lines (12a), each connection line connecting the supply line to an air cell in said series of air cells (1, 2, 3), wherein the flow restrictors are disposed in parallel in the connec^¬ tion lines (12a) to the individual air cells.

4. The massage system for a vehicle seat according to any of the preceding claims, characterized in that a valve (16) is disposed in the supply line structure (10, 12; 10a, 12a) between the pump (14) and said series of air cells (1, 2, 3), said valve being operable by the control or switch unit to be switched between a state in which the fluid connection between pump and said series of air cells is open and a state in which the supply line structure is open to the environment for venting the supply line struc^¬ ture .

5. The massage system according to any of the claims 1 to 3, characterized in that the means for controlling air flow is free of any controllable valve and in that the venting means are provided by an opening provided with a venting flow restrictor which is open to the environment so that there is a continuous venting flow to the environment dur^¬ ing operation of the massage system, wherein the venting flow restrictor and the pump are arranged such that the pump can provide sufficient air flow to inflate the series of air cells while air is leaking through the venting flow restrictor .

6. The massage system according to claim 2, or on claim 4 or

5, when dependent on claim 2, characterized in that the first flow restrictor (Rl) downstream of the pump in the supply line (10) has a throughgoing passage of an effec^¬ tive inner diameter of 0,4 to 2 mm, the second flow resistor (R2) upstream of the second cell has an effective in^¬ ner diameter of 5 - 80% of the diameter of the first flow resistor, and that the third flow resistor (R3) upstream of a third cell in said series of air cells has an effec^¬ tive inner diameter in the range of 10 - 100% of the di^¬ ameter of the second flow resistor.

7. The massage system for a vehicle seat according to claim

6, characterized in that the first flow resistor (Rl) in the supply line (10) upstream of the first cell (1) of said series of air cells has an effective inner diameter of 0,5 - 1,5 mm, that the second flow restrictor (R2) in the supply line upstream of a second cell (2) in said se^¬ ries of air cells as an effective inner diameter of 10 - 30% of the diameter of the first flow restrictor, and that a third flow restrictor (R3) in the supply line upstream of a third cell (3) in said series of air cells has an ef^¬ fective inner diameter of 50 - 80% of the diameter of the second flow resistor.

8. The massage system according to claim 3 or any of claims 4 or 5, when dependent on claim 3, characterized in that a first flow restrictor (Rl) in the connection line upstream of the first cell (1) has a through going passage with an effective inner diameter of 0,4 - 2 mm, a second flow restrictor in the connection line upstream to a second cell (2) in said series of air cells has an effective inner di^¬ ameter of 5 - 80% of the diameter of the first flow re^¬ strictor, and that a third flow restrictor (R3) in the connection line upstream of a third cell (3) in said se^¬ ries of air cells has a through going passage with an ef^¬ fective inner diameter of 5 - 80% of the second flow re^¬ strictor .

9. The massage system according to claims 7 or 8, characterized in that the through going passages of the flow re- strictors (Rl, R2, R3 ) have length in flow direction be^¬ tween 4 and 10 mm.

10. The massage system according to any of the preceding claims, characterized in that a second series of air cells ( 1 ' , 2', 3') is connected to the supply line structure (10, 12; 10a, 12a) in a symmetrical manner to the first series of air cells (1, 2, 3) .