GB2530412A - Seat for a vehicle with feedback loop - Google Patents

Abstract

The seat 10 includes at least one bag 16 arranged in at least one region 12, 14 of the seat, which is configured to support a seat occupant. A stiffness of the at least one bag can be varied. The bag contains a plurality of particles (18, Figure 3) and a fluid, such as air. The stiffness of the bag can be varied by varying a quantity of the fluid contained within the at least one bag. The bag may have an elastic wall material (24, Figure 3). A pipe 20 may be used to provide/discharge the fluid to/from the bag/s. A pressure sensor and control unit (26, 28, Figure 4) may be used to control the quantity of fluid contained in the bag. The control unit may also operate a blower, vacuum pump and valve (34, 32, 30, Figure 4). Multiple bags may be arranged in a seat cushion 12 and/or in a backrest 14 of the seat.

Description

Seat for a vehicle with feedback ioop The invention relates to a seat for a vehicle, wherein at least one bag is arranged in at least one region of the seat. The at least one region of the seat is configured to support a seat occupant. A stiffness of the at least one bag can be varied. The invention further relates to a vehicle with at least one seat.

Document WO 03/068558 Al describes a seat for a vehicle, which is fitted internally with a number of air chambers. The air chambers are inflated and deflated to adapt the stiffness and the shape of the seat. Herein, support cushions can contain bags which are filled with a material, of which the viscosity and hardness depend on the parts of the body which is supported.

Document US 4 722 550 A describes a seat assembly for a motor vehicle with hardness changing members disposed within the seat. The hardness changing members can be airbags disposed at the back of seat springs located inside the seat.

Document DE 199 08 655 Cl describes a seat for a vehicle, wherein a seat cushion contains two rings with a free space in the center of each ring. The ring rooms of the rings are filled with a fluid, and a pressure of the fluid can be varied.

Document US 2012/0280421 Al describes a jamming apparatus, wherein a granular material is contained within a bladder. The bladder takes on a rigid state as the granular material becomes densely packed due to a jamming pressure. The jamming pressure can be due to mechanical squeezing or to a difference in fluid pressure. For example, vacuum pressure can be applied to achieve the jamming pressure.

It is an object of the present invention to provide a seat of the initially mentioned kind, which improves the comfort for the seat occupant, and a vehicle with such a seat.

This object is solved by a seat having the features of claim 1 and by a vehicle having the features of claim 10. Advantageous configurations with convenient further developments of the invention are specified in the dependent claims.

In the seat according to the invention the at least one bag contains a plurality of particles and a fluid. The stiffness of the at least one bag can be varied by varying a quantity of the fluid contained within the at least one bag. Accordingly, granular jamming is utilized to change the stiffness or rigidity of the at least one bag. According to this process, the granular material becomes more rigid when its density increases. This can be achieved by evacuating a part of the fluid contained within the at least one bag. As the rigidity or stiffness of the at least one bag can be varied according to the particular profile of the seat occupant, the seat provides improved comfort to the seat occupant.

Preferably, the particles contained within the at least one bag have a high material coefficient of friction and an interlocking geometry. This greatly increases the strength and the stiffness of the at least one bag once the granular material in the form of the particles is sufficiently jammed, i.e. when particles contact each other.

The pressure which leads to the jamming of the particles can be due to a mechanical squeezing of the at least one bag. Also, a differential pressure, i.e. a difference between the pressure inside the at least one bag and outside the bag, can lead to the jamming of the granular material. To vary this differential pressure, more fluid can be introduced into the at least one bag or fluid can be evacuated from the at least one bag.

Preferably, a wall material of the at least one bag is elastic. Thus, the bags are free to expand, or to contract when an external force is applied to the bags. However, the bags remain fixed to a base material of the seat.

It has further proven advantageous if the seat comprises at least one pipe for providing the fluid to a plurality of bags and/or to discharge the fluid from the plurality of bags. In this way, the stiffness of the plurality of bags can be varied simultaneously. As the fluid in particular air can be utilized. Then the at least one pipe is configured as a pneumatic pipe.

In a further advantageous embodiment, the seat comprises at least one pressure sensor for determining the pressure in the at least one bag. A control unit is configured to process a signal of the at least one pressure sensor and to control the quantity of the fluid contained within the at least one bag. With a given external pressure applied to the at least one bag, a density of the particles and therefore a degree of jamming of the particles depends only on the pressure within the at least one bag. Thus, by measuring the pressure within the at least one bag directly by means of the pressure sensor, the stiffness can be adjusted accordingly. This allows in particular to customize the comfort for a seat occupant based on the human profile.

For example, the seat occupant can desire a certain stiffness or rigidity of the at least one bag, which can be controlled using the feedback from the at least one pressure sensor.

Thus, based on the body profile of the seat occupant, the seat gives the occupant a

comfortable seating.

Preferably, the control unit is configured to operate at least one pump device for providing the fluid to the at least one bag and/or for evacuating the fluid from the at least one bag.

For example, a blower can be utilized to provide the fluid to the bags and a vacuum pump can be utilized to evacuate the fluid from the bags. By operating the at least one pump device, great flexibility can be achieved in varying the stiffness of the at least one bag.

Further, a change in stiffness can be achieved particularly rapidly.

The control unit can further be configured to operate at least one valve arranged at an outlet of the at least one bag. By opening the valve, fluid can be released from the at least one bag, if the external pressure is greater than the internal pressure within the at least one bag. On the other hand, a pressure which is lower or higher than the external pressure applied to the at least one bag can be readily maintained by closing the valve.

It has further proven advantageous if the seat comprises means for determining an external pressure applied to the at least one bag. As the atmospheric pressure is rather constant or can be readily measured or estimated dependent on the geodetic height, the external pressure applied by the seat occupant depends on the weight of the seat occupant and on the morphology of the seat occupant.

In particular, by taking into consideration the external pressure applied by the seat occupant to the at least one bag, the same stiffness of the at least one bag can be provided to different seat occupants having different weights and/or different morphologies. For example, a weight sensor can be utilized to determine the external pressure applied to the at least one bag by the seat occupant. The stiffness of the at least one bag depends on the difference between the internal pressure within the at least one bag and the external pressure applied to the at least one bag. Therefore knowledge of the external pressure and of the internal pressure allows for a particularly good control of the stiffness of the at least one bag. This can in particular be achieved by the control unit.

In a further advantageous embodiment, the seat occupant can choose a desired stiffness of the at least one bag, which can then be controlled by the control unit.

A plurality of bags can be arranged in a pattern with spaces between the bags. Herein, a base material of the seat, which is arranged in the spaces, is permeable for air blown towards the seat occupant. By providing such porous spaces between the bags, a ventilation of the seat occupant is facilitated as air moves through the spaces between the bags. This air can in particular be heated or cooled in order to heat or cool the seat occupant. Such an arrangement of the bags provides an advantageous structure for an efficient heat transfer.

Finally, it has proven advantageous if a plurality of bags is arranged in a seat cushion and/or in a backrest of the seat. Thus, these regions of the seat, which are configured to support the seat occupant, can have a variable stiffness depending on the quantity of the fluid within the bags.

The vehicle according to the invention comprises at least one seat according to the invention. The advantages and preferred embodiments described with respect to the seat correspondingly apply to the vehicle according to the invention.

The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the invention.

Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures or explained, but arise from and can be generated by separated feature combinations from the explained implementations.

Further advantages, features and details of the invention are apparent from the claims, the following description of preferred embodiments as well as based on the drawings in which features having analogous functions are designated with the same reference signs.

Therein show: Fig. 1 schematically and in a side view a seat for a vehicle with a plurality of flexible bags filled with a granular material, wherein the bags are arranged in the region of a backrest and of a seat cushion of the seat; Fig. 2 the seat according to Fig. 1 in a top view; Fig. 3 one of the bags with the granular material shown in an unjammed state and in a jammed state; Fig. 4 a control mechanism for varying the stiffness of one of the bags; and Fig. 5 air blown through a base material of the seat cushion to improve the thermal comfort for a seat occupant.

Fig. 1 schematically shows a seat 10 for a vehicle with a seat cushion 12 and a backrest 14. These regions of the seat 10 support a seat occupant (not shown) utilizing the seat 10. These parts or regions of the seat 10 comprise multiple flexible bags 16 which contain a granular material in the form of particles 18 (see Fig. 3). The bags 16 also contain a fluid such as air which is provided to the bags 16 by a pipe 20. In the example shown in the figures, the pipe 20 has a plurality of branches 22 leading to the individual bags 16. A wall material 24 of the individual bags 16 is flexible or elastic (see Fig. 3).

By varying the quantity of the fluid contained within each one of the bags 16, the stiffness of the bags 16 can be varied. This process of granular jamming is illustrated in Fig. 3. The bag 16 shown on the left in Fig. 3 comprises the particles 18 in an unjammed state, in which the particles 18 can move rather freely with respect to one another. In the jammed state of the particles 18 shown in the bag 16 on the right side in Fig. 3, the particles 18 are more densely packed. This increases the rigidity or stiffness of the bag 16. If the particles 18 have a high material coefficient of friction and an interlocking geometry, the strength and stiffness of the system can be greatly increased by evacuating the fluid from the bag 16 through the branches 22 and the pipe 20, respectively.

As can be well seen in Fig. 1 and Fig. 2, the bags 16 are preferably arranged in a lattice or pattern within the seat cushion 12 and the backrest 14 of the seat. Further, the bags 16 are connected to the network of pneumatic pipes in the form of the pipe 20 and the branches 22. By evacuating a fluid such as air from the bags 16, the stiffness of the bags 16 can be increased. In a like manner, by increasing the quantity of the fluid contained within the bags 16, the rigidity or stiffness of the bags 16 can be decreased.

The pressure exerted on the bags 16, which leads to the granular jamming of the particles 18, can be due to mechanical squeezing, for example when the seat occupant utilizes the seat 10. However, the pressure also depends on the difference between the pressure inside the bags 16 and the external pressure applied to the wall material 24 of the bags 16. This differential pressure can be influenced by providing the fluid such as air to the bags 16 or by evacuating the fluid from the bags 16.

It can be derived from Fig. 4 that the internal pressure within the bag 16 can be measured by means of a pressure sensor 26 arranged within the bag 16. The pressure measured by the pressure sensor 26 is communicated to a control unit 28. The control unit 28 opens or closes a valve 30 arranged in the branch 22 leading to the individual bag 16. Further, the control unit 28 can operate a vacuum pump 32 and a blower 34, which are configured to evacuate the fluid from the bags 16 or to provide the fluid to the bags 16, respectively.

For example by operating further valves 42, 44 arranged downstream of the vacuum pump 32 and of the blower 34, respectively, the control unit 28 can control the quantity of the fluid to be evacuated from the bags 16 or to be provided to the bags 16.

Depending on the force or pressure externally applied to the bags 16 and on the pressure within the bags 16. a differential pressure exists. This differential pressure influences the degree of jamming of the particles 18 and therefore the packing density of the particles 18. The degree of jamming of the particles 18 correlates with the stiffness of the bag 16.

Thus, the control unit 28 provides a feedback loop for controlling the stiffness of the bags 16. Therefore, a seat comfort based on granular jamming using feedback control provides the seat occupant with a comfort based on his or her body profile. In this way a customized comfort based on the human profile can be achieved.

As can be particularly well seen in Fig. 5, the bags 16 are fixed to a base material 36 of the seat 10, but are still free to expand and contract when a force is applied to the bags 16. In spaces 38 between the bags 16 forming a pattern or lattice, the base material 36 is porous and thus permeable for air 40 blown towards the seat occupant. This porous base material 36 facilitates ventilation and the movement of the air 40 through the spaces 38 towards the seat occupant.

As the air 40 can be heated or cooled, this lattice arrangement of the bags 16 provides a promising structure for an efficient heat transfer. Therefore this concept helps in improving the thermal comfort provided by the seat 10.

List of reference signs seat 12 seat cushion 14 backrest 16 bag 18 particle pipe 22 branch 24 waIl material 26 pressure sensor 28 control unit valve 32 vacuum pump 34 blower 36 base material 38 space air 42 valve 44 valve

Claims (10)

1. Claims Seal for a vehicle, with at least one bag (16) arranged in at least one region (12, 14) of the seat (10), which is configured to support a seat occupant, wherein a stiffness of the at least one bag (16) can be varied, characterized in that the at least one bag (16) contains a plurality of particles (18) and a fluid, wherein the stiffness of the at least one bag (16) can be varied by varying a quantity of the fluid contained within the at least one bag (16).
2. 2. Seal according to claim 1, characterized in that a wall material (24) of the at least one bag (16) is elastic.
3. 3. Seal according to claim 1 or 2, characterized by at least one pipe (20) for providing the fluid to a plurality of the bags (16) and/or to discharge the fluid from the plurality of the bags (16).
4. 4. Seat according to any one of claims 1 to 3, characterized by at least one pressure sensor (26) for determining the pressure in the at least one bag (16) and a control unit (28) configured to process a signal of the at least one pressure sensor (26) and to control the quantity of the fluid contained within the at least one bag (16).
5. 5. Seat according to claim 4, characterized in that the control unit (28) is configured to operate at least one pump device, in particular a blower (34) and a vacuum pump (32), for providing the fluid to the at least one bag (16) and/or for evacuating the fluid from the at least one bag (16).
6. 6. Seat according to claim 5, characterized in that the control unit (28) is configured to operate at least one valve (30) arranged at an outlet of the at least one bag (16).
7. 7. Seat according to any one of claims 1 to 6, characterized by means for determining an external pressure applied to the at least one bag (16).
8. 8. Seat according to any one of claims 1 to 7, characterized in that a plurality of the bags (16) is arranged in a pattern with spaces (38) between the bags (16), wherein a base material (36) of the seat (1 0), which is arranged in the spaces (38), is permeable for air (40) blown towards the seat occupant.
9. 9. Seat according to any one of claims 1 to 8, characterized in that a plurality of the bags (16) is arranged in a seat cushion (12) and/or in a backrest (14) of the seat (10).
10. 10. Vehicle with at least seat (10) according to any one of claims ito 9.