Patent Description:
Automotive comfort systems with air bladders for shaping the seat cushion or the backrest of an automotive seat are known. Presently such comfort systems comprise motor actuated air pumps that supply compressed air to fill air bladders with the desired amount of air. Further, the filling and release of air of such air bladders is usually controlled by solenoid air valves.

Further, the document <CIT> discloses generally a pump on a piezoelectric basis that is used for filling an air bladder within a headrest of a vehicle seat.

Apart from solenoid valves, it was also known in the prior art to use piezoelectric actuated valves for controlling the filling and release of air of air bladders. For example, the document <CIT> discloses a contour-adjustable seat having air or gas-filled cushions that are controlled by piezo valves. The document <CIT> likewise discloses a vehicle seat with a multitude of air chambers that are controlled by piezoelectric valves.

Document <CIT> discloses a piezoelectric actuating fluid pump integrated on a PCB. The pump shall be used in the field of microfluid systems or devices such as chip cooling systems and chip laboratories due to their small size.

Document <CIT> discloses a microfluid device with external piezoelectric actuator for providing higher pressures than membrane pumps. The device pumps only a very small amount of fluid, wherein each pump stroke is typically in the order of about <NUM> nanoliters.

Document <CIT> discloses a miniature fluid system that is produced in an integrated process. The system is usable as micro pump, micro atomizers, for print heads or industrial printers.

Document <CIT> discloses a seat support and massage system with air cells. The air supply is done in a conventional way with a motor driven pump and a separate manifold controlled by a controller. The used valves can be piezoelectric valves. However, there is still a need to further improve automotive comfort systems comprising air bladders.

The above-mentioned problem is solved by an integrated pump valve unit according to claim <NUM> and by a comfort system for a vehicle seat according to claim <NUM>.

Particularly, the above mentioned problem is solved by an integrated pump valve unit comprising a piezoelectrically actuated air pump portion, comprising at least one pump air chamber and at least one pump piezoelectric element for actuating the pump portion, a piezoelectrically actuated air valve portion, comprising a valve air chamber and at least one valve piezoelectric element for controlling the opening and closing of an air flow through the valve portion, wherein the valve portion is in fluid connection with the pump portion, and wherein the pump portion and the valve portion form a structural unit.

The integrated pump valve unit provides an integration of all mechanical components for filling, holding the pressure and releasing of air to and from an air bladder of an automotive comfort system within one integrated unit. This integration into a structural unit saves additional parts and mounting effort. Further, the integrated pump valve unit due to the integration requires less space than conventional solutions.

Since both the air pump portion and the air valve portion are each piezoelectrically actuated by their respective piezoelectric elements, large and costly mechanical parts, like solenoids and motors can be saved as well. This particularly decreases the overall weight compared to standard pumps and valves and further decreases costs and space consumption. Further, the air pump portion and the air valve portion can be actuated by a common control electronics, since the actuation by piezoelectric elements requires comparable actuation voltages and currents. This reduces effort for the actuation electronics as well as mounting and wiring effort.

Preferably, the valve portion is in a closed state, when no voltage is applied to the valve piezoelectric element.

As structural unit could it be implemented with two different elements: One element comprising the air pump portion and the other element comprising the air valve unit attached together and being in fluid connection between.

Preferably, the pump portion and the valve portion are mechanically connected to each other by connection elements. The mechanical connection between these elements could be made by a bracket, snap hooks, male-female connections, mounting means like screws, rivets, etc. or gluing, welding etc. that attach together both elements such that they from a structural unit. Preferably, the elements are directly connected to each other such that they abut each other or are distanced from each other only by a minimal distance. A minimal distance between the two elements may less than <NUM> or preferably less than <NUM>.

Preferably, the connection elements are also establishing the fluid connection between the pump portion and the valve portion. For example, the connection between the air pump portion and the air valve portion could be made through a rigid hose that mechanically attaches together both elements and simultaneously provides a fluid connection between these elements.

Preferably, the integrated pump valve unit, further comprises a common housing of the pump portion and the valve portion, wherein the common housing constitutes at least a wall of the at least one pump air chamber and at least a wall of a valve air chamber. The structural unit can be provided by providing a common housing for the pump unit and the valve unit. This provides a very compact arrangement of the integrated pump valve unit and minimizes assembly costs. The common housing may comprise injection molded parts, assembled together, as required due to the need for providing a hollow pump air chamber and a hollow valve air chamber.

Preferably, the pump piezoelectric element actuates a pump membrane of the pump portion or the pump piezoelectric element constitutes a pump piezoelectric membrane of the pump portion.

In one alternative the pump portion comprises a movable membrane that is actuated by a pump piezoelectric element. The movements of the piezoelectric element are transferred to pumping movements of the membrane. As an alternative to a membrane a piston or any other movable air propelling element may be used. However, a membrane requires less mechanical effort and no seals between moving elements as it moves in itself and simultaneously seals the pump air chamber.

In a further alternative the pump piezoelectric element constitutes a pump piezoelectric membrane. This pump piezoelectric membrane integrates the function of the membrane with the piezoelectric actuation in one single element. The pump piezoelectric membrane is part of the pump air chamber and is arranged to compress air if a corresponding electrical voltage is applied. Thus, no additional air membrane or air piston or the like are necessary in the pump portion, what makes the integrated pump valve unit very reliable and robust.

The pump portion comprises a first pump air chamber and a second pump air chamber that are both actuated by the at least one pump piezoelectric element. By two air chambers the pump power of the pump portion is doubled, which provides for a faster adjustment of the comfort system.

The first pump air chamber and the second pump air chamber are separated by the pump piezoelectric membrane. The single pump piezoelectric membrane commonly actuates two pump air chambers and pumps air in both movement directions. This minimizes the components of the pump portion and doubles the pumping power of the pump piezoelectric element.

Preferably, the pump piezoelectric membrane has a circular shape. A circular shaped pump piezoelectric membrane provides for an increased piezoelectric movement that corresponds to an increased stroke of the pump portion.

Preferably, air flows coming from the first pump air chamber and from the second pump air chamber are united within the integrated pump valve unit. This further decreases the overall space and weight of the integrated pump valve unit and eliminates any external hoses to combine the air flows of the double acting piezoelectric pump portion having two air chambers.

Preferably, the housing may comprise an air connection channel connecting the air flows from the first pump air chamber and from the second pump air chamber prior to entering into the valve air chamber.

Preferably, the valve piezoelectric element actuates a movable valve membrane, that directly opens and closes an exhaust outlet or the valve piezoelectric element constitutes a movable valve piezoelectric membrane, that directly opens and closes the exhaust outlet. A piezoelectric element for controlling a valve is more reliable and structurally less complicated than a solenoid for controlling a valve.

In one alternative the exhaust outlet of the valve portion is opened and closed by a movable valve membrane. The valve membrane is moved by a piezoelectric element when electrical power is applied to the piezoelectric element.

In another embodiment the exhaust outlet of the valve portion is directly opened and closed by a movable valve piezoelectric membrane. This movable valve piezoelectric membrane moves when electrical power is applied to it. The valve piezoelectric membrane integrated the function of a membrane and the piezoelectric actuation thereof in a single element. This provides a very reliable and structurally easy construction of the piezoelectrically actuated valve.

Preferably, the valve piezoelectric membrane comprises an air opening for allowing an air flow from one side of the valve piezoelectric membrane to the other side of the valve piezoelectric membrane. The air opening allows the piezoelectrically actuated valve to be supplied with air from two sides of the valve piezoelectric membrane.

Preferably, the valve piezoelectric membrane may be designed such that it does not cover completely the diameter of the valve air chamber. Thus, it acts as the active element to close and open the valve portion but does not separate the valve air chamber into to isolated air chambers.

Preferably, the valve piezoelectric membrane has a circular shape. A circular shaped valve piezoelectric membrane provides for an increased piezoelectric movement that corresponds to an increased opening and closing movement of the valve. This increases the possible throughput through the valve in open state.

Preferably, the integrated pump valve unit further comprises a valve seal arranged within the valve air chamber and surrounding the exhaust outlet. Such a seal cooperates directly with a face of the valve membrane or a face of the valve piezoelectric membrane, which reduces the number of parts of the valve portion.

Preferably, the integrated pump valve unit further comprises at least one air inlet check valve, for allowing an air flow into the at least one pump air chamber and for blocking an air flow out of the at least one pump air chamber; and/or at least one air outlet check valve, for allowing an air flow out of the at least one pump air chamber and for blocking an air flow from the valve chamber into the at least one pump air chamber.

Preferably, the integrated pump valve unit further comprises at least one air channel fluidly connecting the at least one pump air chamber with the valve air chamber.

Preferably, the at least one air channel comprises outer walls of the common housing. The use of outer walls of the housing for forming an air channel on the one hand reduces the complexity for forming the common housing and allows for integrating an air outlet check valve into the air path from the pump portion to the valve portion.

Preferably, the at least one air channel comprises at least one cover, attached to the common housing. The use of a separate cover as part of an air channel allows an easy assembly the air outlet check valve within the air path between pump portion and valve portion. The air outlet check valve is easily accessible when the cover is not mounted, yet. Further, such an arrangement is particularly favorable, since the common housing and the cover can be made separately, preferably of a plastic material, by injection molding.

Preferably, the pump portion comprises a general shape of a flat disc and the valve portion comprises a general shape of a flat disc, wherein the common housing is provided such that the pump portion and the valve portion are arranged in the same disc orientation and side-by-side. Such a design and arrangement of pump portion with respect to the valve portion provides a very flat pump valve unit that can easily be integrated into a backrest or seat cushion of a vehicle seat.

The above-mentioned problem is also solved by a comfort system for a vehicle seat, comprising at least one air bladder fluidly connected to at least one integrated pump valve unit as described above.

In the following, preferred embodiments of the invention are disclosed by reference to the accompanying figures, in which shows:.

In the following preferred embodiments of the invention are described with respect to the figures.

As shown in <FIG> an integrated pump valve unit <NUM> is part of a comfort system <NUM> arranged within the backrest <NUM> or a seat cushion <NUM> of an automotive seat <NUM>. Preferably, the integrated pump valve unit <NUM> is connected to an air bladder <NUM> of the comfort system <NUM> via an air conduit <NUM> and provides for a controlled inflation and deflation of the air bladder <NUM>. The integrated pump valve unit <NUM> has the following functionality: The air pump unit <NUM> takes in air from the ambient, compresses it to some extend and provides this compressed air to the air valve portion <NUM>. The air valve portion <NUM> preferably provides the compressed air to an air bladder <NUM> via the air conduct <NUM> and is able to release the air in a controlled manner from the air bladder <NUM> to the ambient.

<FIG> show a schematic side sectional view of the integrated pump valve unit <NUM>. The pump valve unit <NUM> comprises a piezoelectrically actuated air pump portion <NUM> and a piezoelectrically actuated air valve portion <NUM> that are fluidly connected to each other. The air pump portion <NUM> and the air valve portion <NUM> have a common housing <NUM> that integrates the two functional components <NUM>, <NUM> into one single integrated unit <NUM>.

<FIG> shows the integrated pump valve unit <NUM> in a stand-by condition in which the air pump portion <NUM> does not pump air (off state) and the air valve portion <NUM> does not release air into the ambient (closed state). In this stand-by condition the air pressure and/or volume in an air bladder <NUM> is kept constant.

<FIG> shows the integrated pump valve unit <NUM> in an inflation condition in which the air pump portion <NUM> pumps air (on state) to the valve portion <NUM> and further to the air bladder <NUM> for inflation. The air valve portion <NUM> does not release air into the ambient (closed state). In this stand-by condition the air pressure and/or volume in the air bladder <NUM> is increased.

<FIG> shows the integrated pump valve unit <NUM> in a deflation condition in which the air pump portion <NUM> does not pump air (off state) and the valve portion <NUM> releases air into the ambient (open state). In this deflation condition the air pressure and/or volume in the air bladder <NUM> is decreased.

In the shown embodiment the pump portion <NUM> comprises a piezoelectric element in the form of a pump piezoelectric membrane <NUM>, that actuates the pump portion <NUM>, a first pump air chamber <NUM> above the pump piezoelectric membrane <NUM> and a second pump air chamber <NUM> below the pump piezoelectric membrane <NUM>. The pump piezoelectric membrane <NUM> is preferably a thin circular disc that is able to reciprocally deform or swing in two directions if a corresponding actuation voltage is applied to it (see <FIG>). By this movement reciprocally an overpressure and an underpressure is generated in each of the two pump air chambers <NUM>, <NUM>. The pump piezoelectric membrane <NUM> is mounted by its periphery to side walls <NUM> of the air chambers <NUM>, <NUM>.

As an alternative (not shown), an elastic pump membrane can be provided instead of the pump piezoelectric membrane <NUM>, wherein the elastic pump membrane is moved by a separate piezoelectric element.

The first pump air chamber <NUM> comprises a first air inlet check valve <NUM> arranged within the upper pump wall <NUM> of the housing <NUM>. The first air inlet check valve <NUM> allows an air flow into the first pump air chamber <NUM> and blocks an air flow out of the first pump air chamber <NUM>.

Similarly, the second pump air chamber <NUM> preferably may comprise a second air inlet check valve <NUM> that allows an air flow into the second pump air chamber <NUM> and blocks an air flow out of the second pump air chamber <NUM>. The second air inlet check valve <NUM> may be arranged within the lower pump wall <NUM> of the housing <NUM>.

Thus, when the pump piezoelectric membrane <NUM> is moving downwards by application of an electric voltage to it, an underpressure is generated in the first pump air chamber <NUM>, the first air inlet check valve <NUM> opens and air from the ambient is sucked into the first pump air chamber <NUM>. Simultaneously, when the pump piezoelectric membrane <NUM> is moving downwards, air within the second air chamber <NUM> is compressed and the second air inlet check valve <NUM> is closed. The compressed air is forced into a second air channel <NUM> that connects the second pump air chamber <NUM> with the valve air chamber <NUM>.

When the pump piezoelectric membrane <NUM> is moving upwards by application of an electric voltage to it an overpressure is generated in the first pump air chamber <NUM>, the first air inlet check valve <NUM> is closed and the compressed air is forced into a first air channel <NUM> that connects the first pump air chamber <NUM> with the valve air chamber <NUM>. Simultaneously, when the pump piezoelectric membrane <NUM> is moving upwards, within the second air chamber <NUM> an underpressure is generated in the second pump air chamber <NUM>, the second air inlet check valve <NUM> opens and air from the ambient is sucked into the second pump air chamber <NUM>.

Thus, by the reciprocal movement of the pump piezoelectric membrane <NUM> the pump portion <NUM> generates compressed air that is supplied to the valve portion <NUM> via the first air channel <NUM> and the second air channel <NUM>. The first air channel <NUM> may be constituted by upper outer walls <NUM> and <NUM> of the common housing <NUM> and by a first cover <NUM>, attached to the common housing <NUM>. The first air channel <NUM> fluidly connects the first pump air chamber <NUM> with the valve air chamber <NUM> via an opening <NUM>. The opening <NUM> may be in the upper outer wall <NUM>. Similarly, the second air channel <NUM> may be constituted by lower outer walls <NUM> and <NUM> of the common housing <NUM> and by a second cover <NUM>, attached to the common housing <NUM>. The second air channel <NUM> fluidly connects the second pump air chamber <NUM> with the valve air chamber <NUM>, via an air connection channel <NUM> in the housing <NUM> connecting the second air channel <NUM> with the first air channel <NUM>. Alternatively, the second air channel <NUM> can lead to an opening <NUM>. The opening may be in the lower outer wall <NUM> of the valve portion <NUM> and into the valve air chamber <NUM>.

The valve portion <NUM> comprises a valve piezoelectric element <NUM> for controlled opening and closing an air flow through the valve portion <NUM>. The valve piezoelectric element <NUM> is preferably in form of a movable valve piezoelectric membrane <NUM> that directly opens and closes an exhaust outlet <NUM> that leads to the ambient. The valve piezoelectric membrane <NUM> preferably has a circular shape and is connected to side walls <NUM>, <NUM> of the valve air chamber <NUM> at the periphery of the valve piezoelectric membrane <NUM>. If an appropriate voltage is applied to the valve piezoelectric membrane <NUM> it bends or deforms to the open state of the valve portion <NUM> as shown in <FIG>. If no voltage is applied to the valve piezoelectric membrane <NUM> it is substantially flat as shown in <FIG> and the valve portion <NUM> is in the closed state.

As an alternative (not shown), an elastic valve membrane may be provided instead of the valve piezoelectric membrane <NUM>, wherein the elastic valve membrane is actuated by a separate valve piezoelectric element.

The exhaust outlet <NUM> is preferably arranged near the center of the outer wall <NUM> of the housing <NUM>. A valve seal <NUM> of an elastomeric material may be arranged within the valve air chamber <NUM> surrounding the exhaust outlet <NUM> for improving the airtightness of the valve portion <NUM> in closed state. The valve piezoelectric membrane <NUM> directly contacts the valve seal <NUM> and closes the valve portion <NUM> without a voltage applied. Thereby, the exhaust outlet <NUM> is closed and the air within the valve air chamber <NUM> cannot flow to the ambient.

The valve piezoelectric membrane <NUM> may not separate the valve air chamber <NUM> into two isolated chambers. Preferably, it may comprise an air opening <NUM> for allowing an air flow from one side of the valve piezoelectric membrane <NUM> to the other side of the valve piezoelectric membrane <NUM>. This is particularly useful, if the pump portion <NUM> is a double acting pump that provides air to the valve air chamber <NUM> at both sides of the valve piezoelectric membrane <NUM>. If the valve piezoelectric membrane <NUM> comprises an air opening <NUM> the air connection channel <NUM> connecting the first and second air channels <NUM>, <NUM> can be saved, what further may decrease the space of the integrated pump valve unit <NUM>.

The integrated pump valve unit <NUM> further comprises an air outlet <NUM> that is connected to the bladder <NUM> via the air conduit <NUM>. Since the valve portion <NUM> leads through the air coming from the pump portion <NUM> to the air bladder <NUM> during filling the air bladder <NUM> only one single air outlet <NUM> at the valve portion <NUM> is needed for connecting the integrated pump valve unit <NUM> with the air bladder <NUM>. Via this single air outlet <NUM> the filling and the releasing of air of the air bladder <NUM> can be done.

Further, the integrated pump valve unit <NUM> preferably comprise one or more outlet check valves <NUM>, <NUM> that allow an air flow out of the at pump air chambers <NUM>, <NUM> into the valve chamber <NUM> but block an air flow in the reverse direction. The first and second outlet check valves <NUM>, <NUM> can be arranged as shown in <FIG> in the upper and lower outer walls <NUM>, <NUM> of the pump portion <NUM> leading into the air channels <NUM>, <NUM>. This position allows for an easy installation of the first and second outlet check valves <NUM>, <NUM> prior to closing the air channels <NUM>, <NUM> by the covers <NUM>, <NUM>. Alternatively, the first and second outlet check valves <NUM>, <NUM> could also be arranged within the air channels <NUM>, <NUM> or at the openings <NUM>, <NUM> of the valve portion outer walls <NUM>, <NUM>.

As shown in <FIG> and <FIG> the integrated pump valve unit <NUM> comprises a very thin and compact shape, wherein the pump portion <NUM> comprises a general shape of a flat disc and the valve portion <NUM> also comprises a general shape of a flat disc and both portions are integral due to the common housing <NUM> or may be attached one to the other. The diameter of the valve portion <NUM> may be smaller than the diameter of the pump portion <NUM> since the valve piezoelectric membrane <NUM> may be smaller than the pump piezoelectric membrane <NUM>. This is because the diameter of the pump piezoelectric membrane <NUM> determines the air power provided by the pump unit <NUM>, whereas the diameter of the valve piezoelectric membrane <NUM> is determined by the opening stroke thereof for providing the necessary throughput of air out of the exhaust outlet <NUM>.

As shown in <FIG>, the common housing <NUM> is provided such that the pump portion <NUM> and the valve portion <NUM> are arranged in the same disc orientation and side-by-side. This provides a very thin (see <FIG>) and compact integrated pump valve unit <NUM> that can easily be installed with a vehicle seat <NUM>. The longest length L of the housing <NUM> can preferably be below <NUM>, preferably below <NUM> and preferably is <NUM>. The thickness of the integrated pump valve unit <NUM> can preferably be below <NUM>, preferably below <NUM> and preferably is <NUM>.

Claim 1:
Integrated pump valve unit (<NUM>) for providing compressed air to an air bladder of an automotive comfort system within an automotive seat, the integrated pump valve unit (<NUM>) comprising:
a. a piezoelectrically actuated air pump portion (<NUM>), comprising at least one pump air chamber (<NUM>, <NUM>) and at least one pump piezoelectric element (<NUM>) for actuating the pump portion (<NUM>);
b. a piezoelectrically actuated air valve portion (<NUM>), comprising a valve air chamber (<NUM>) and at least one valve piezoelectric element (<NUM>) for controlling the opening and closing of an air flow through the valve portion (<NUM>), wherein the valve portion (<NUM>) is in fluid connection with the pump portion (<NUM>); and wherein
c. the pump portion (<NUM>) and the valve portion (<NUM>) form a structural unit;
characterized in that
d. the pump portion (<NUM>) comprises a first pump air chamber (<NUM>) and a second pump air chamber (<NUM>) that are both actuated by the at least one pump piezoelectric element (<NUM>) in form of a pump piezoelectric membrane (<NUM>) that separates the first pump air chamber (<NUM>) and the second pump air chamber (<NUM>).