WO2000021417A1

WO2000021417A1 - Damping device

Info

Publication number: WO2000021417A1
Application number: PCT/EP1999/007535
Authority: WO
Inventors: Holger Pötzsch
Original assignee: Metzeler Schaum Gmbh
Priority date: 1998-10-10
Filing date: 1999-10-07
Publication date: 2000-04-20
Also published as: DE19908820A1; EP1119275A1

Abstract

The invention relates to a damping device (20) for a seat (30), especially a vehicle seat, comprising a first deformable hollow body (16), said hollow body being filled with a spring-elastic filling (2), and having a second hollow body (4) which is connected to the first hollow body (16). Both hollow bodies (16, 4) are filled with a fluid under a determined pressure. According to the invention, both hollow bodies (16, 4) are interconnected via at least one valve (6) which opens when a determined excess pressure is reached in the first hollow body (16) with regard to the second hollow body (4), and the valve closes when this excess pressure is fallen short of. Both hollow bodies (16, 4) are additionally interconnected via at least one back flow orifice (3). Under applied force, the volume of the first hollow body (16) is decreased so that the valve (6) opens. The adjusting rise in pressure counteracts the applied force. Once the applied force is removed, the valve (6) closes and the pressure equalization occurs only via the back flow orifice (3) so that the first hollow body (16) only expands slowly. This makes it possible to reliably avoid undesired swinging movements, especially during shock-like applied forces.

Description

Damping device

The present invention relates to a damping device for a seat, in particular a vehicle seat, with a first deformable hollow body, which is filled with a resilient filling, and a second hollow body, which is connected to the first hollow body, both hollow bodies with a fluid under a certain Pressure are filled.

Such a damping device is known from US 4 204 657. This document describes a seat in which the seat cushion and the back cushion are designed as a coherent hollow body and are connected to a cover in the form of an elastic expansion tank. The expansion tank, the seat cushion and the back cushion are filled with a fluid, in particular air. When the pressure changes, the volume of the expansion tank changes. In particular when the seat is loaded by the body weight, the internal pressure in the hollow body is increased, so that the expansion tank expands.

The known damping device can absorb a comparatively large external force due to the support by the fluid. When such a force acts, the seat cushion and, if necessary, the backrest are compressed, so that an increase in pressure occurs. This pressure increase counteracts the force gene and at the same time leads to a displacement of the fluid in the expansion tank, which then expands. As soon as the external force is reduced, the fluid immediately flows out of the expansion tank into the seat cushion and the back cushion. The energy stored in the damping device due to the force acting from the outside is released suddenly. A rocking movement thus occurs, which is reinforced by the elasticity of the expansion tank. The rocking movement leads to a subjectively uncomfortable sitting feeling. If the frequency of the rocking movement is close to a resonance frequency, there is also a risk of damage and injury.

It is therefore an object of the present invention to provide a damping device which can absorb high forces and at the same time enables a pleasant sitting feeling, in particular while avoiding rocking movements.

According to the invention, this object is achieved in a damping device of the type mentioned in the introduction in that the two hollow bodies are connected to one another via at least one valve, which opens when the pressure exceeds a certain level in the first hollow body and closes when the pressure falls below this pressure, and in that the two hollow bodies are connected to one another via at least one return flow bore.

As previously, the damping device according to the invention provides damping of the acting forces via a fluid and pressure build-up. As a result, progressive damping increases with the load. At the same time, a rocking effect is completely excluded. As soon as the overpressure in the the first hollow body has dropped to a certain extent relative to the second hollow body, the valve closes. Pressure equalization between the two hollow bodies is then only possible via the return flow bore. The backflow bore allows only a slow backflow of the fluid from the second into the first hollow body. There is no comparatively rapid flow as when the valve is open. Therefore, if the external force drops, there is only a slow pressure equalization. Sudden backflow of the fluid into the first hollow body, as in the known damping devices, is reliably avoided. This also suppresses the unwanted rocking effect. Static loads are compensated for by the pressure increase.

In other words, changes in volume in the first hollow body are rapidly diverted into the second hollow body until pressure equalization and the displaced volume is metered back through a smaller opening or bore.

The pressure equalization takes place via one or more backflow bores. If the external force drops, the pressure is equalized within a certain time. Thereafter, the damping device according to the invention can again reliably dampen high external forces.

The speed of the pressure equalization between the first and second hollow body depends not only on the number and size of the return flow bores, but also on the size and geometric design of the damping device. Another influencing factor is the external force. The speed of the pressure equalization between the first and second hollow body is dependent on speed of these parameters set so that the unwanted rocking movement is reliably suppressed.

Air is advantageously used as the fluid for filling the two hollow bodies. Of course, the use of another gas or liquid is also possible.

Advantageous refinements and developments of the invention emerge from the dependent claims.

The return flow bore is advantageously integrated into the valve or, alternatively, is formed separately from the valve. The integration into the valve enables a structurally simple construction of the damping device according to the invention and a simple and quick assembly. The separate design of the return flow bore results in greater flexibility and better adaptation to different boundary conditions.

In an advantageous embodiment, the size of the return flow bore is significantly smaller than the free cross section of the valve, in particular smaller than 50% of the free cross section, preferably smaller than 30% of the free cross section. If several return flow bores are used, the size of the individual return openings is added up. Since the size of the return flow bores is significantly smaller than the free cross section of the valve, the pressure equalization takes place slowly when the valve is closed, as in the procedure according to the invention. According to an advantageous embodiment, the resilient filling consists of foam. Foam is lightweight and therefore well suited for use in vehicle seats. It also has the desired resilience.

In an advantageous development, the resilient filling consists of an open-cell foam. As a result, the air volume contained in the first hollow body and available for damping is increased.

The second hollow body is advantageously provided with a valve for pressure equalization with the surroundings. Such a valve is particularly useful when using air as a fluid for filling the two hollow bodies. The valve is designed as a compensating valve, which prevents an impermissibly high pressure rise in the second hollow body and at the same time ensures that the two hollow bodies are completely filled in the unloaded state. The first hollow body is expanded by the resilient filling, and the resulting vacuum creates the desired filling.

In an advantageous development, the second hollow body is designed as a rigid body. In this way, a defined total volume is made available, which consists of the volume of the two hollow bodies. This total volume is reduced under load, so that the desired pressure increase occurs.

According to an advantageous embodiment, the volume of the first hollow body in the unloaded state is at least 40% of the total volume of the two hollow bodies. This ensures that very large loads can be dampened by compressing the first hollow body. The invention further relates to a seat, in particular a vehicle seat, using a damping device described above. According to the invention, the damping device is arranged in the area of the seat and / or the backrest. In this way, reliable damping of loads that act on the seat from the front or from above is achieved.

The invention is described in more detail below on the basis of exemplary embodiments, which are shown schematically in the drawing. Identical or functionally identical components are provided with the same reference symbols throughout. It shows:

1 shows a vertical section through a seat using a first embodiment of the damping device according to the invention;

Figure 2 is an enlarged view of the valve for connecting the two

Hollow body from Figure 1;

Figure 3 is an enlarged view of the valve for pressure compensation with the

Environment from Figure 1;

Figure 4 shows a horizontal section through a second embodiment of the damping device according to the invention;

Figure 5 is a plan view of the second hollow body;

Figure 6 is an illustration of a sealing ring;

FIG. 7 shows a vertical section through a third exemplary embodiment of the damping device according to the invention; and

Figure 8 is a view of a seat using the damping device shown in Figure 7. FIG. 1 shows a vertical section through a seat 30 using two damping devices 20. One of the damping devices 20 is arranged in the region of the seat surface and the other in the region of the backrest of the seat 30. Each of the damping devices 20 comprises a first elastic hollow body 16 and a second hollow body 4 designed as a rigid body. The elastic hollow body 16 is filled with a resilient filling 2 made of an open-cell foam. The entire damping device 20 is covered with a decorative padding 1. In the illustrated embodiment, the two hollow bodies 4, 1 6 are filled with air. To equalize the pressure, they are connected to one another via a valve 6 and backflow bores 3. One or more compression elements 5 are arranged in the second hollow body 4 and immovably fixed. The second hollow body 4 is further provided with a valve 1 2 for pressure equalization with the environment. The backflow bores 3 allow only a slow backflow of the fluid into the first hollow body 1 6.

If a force from the outside occurs in accordance with arrow 17, the first hollow body 16 is pressed together with its filling 2. This reduces its volume so that an increase in pressure occurs. Due to this overpressure in the first hollow body 1 6 relative to the second hollow body 4, the valve 6 opens, so that air is displaced from the hollow body 1 6 into the hollow body 4. This results in an increase in pressure in the hollow body 4. As soon as the overpressure in the hollow body 1 6 has decreased to a certain value in relation to the hollow body 4 or a pressure equalization has been brought about, the valve 6 closes. The two hollow bodies 4, 1 6 are then only connected to one another via the backflow bores 3. If the force acting from the outside is reduced, only a slow pressure equalization between the hollow bodies 4, 16 can therefore take place. This pressure equalization is ensured by the see filling 2 of the hollow body 1 6 supported. Unwanted rocking movements, which can occur in known damping devices due to shock loads, are reliably suppressed.

The valve 1 2 for pressure equalization with the environment opens only at an impermissibly high pressure in the hollow body 4. By means of a suitable construction of this valve 1 2, the damping device 20 can be adapted to different loads and applications. If the damping device 20 is not loaded for a longer period of time, then a complete pressure equalization with the surroundings is established via the valve 1 2. Air that may have escaped from the damping element 20 during operation is reliably replaced.

The compression elements 5 accommodated in the hollow body 4 are compressed when the pressure increases. By using different compression elements 5, an adaptation to different boundary conditions is also achieved. Depending on the individual case, the compression elements 5 can be omitted completely.

The use of a spring-elastic filling 2 made of open-cell foam allows the air to be displaced from the hollow body 16 into the hollow body 4 under load. Little energy is therefore stored in the hollow body 1 6. A sudden expansion when relieved, which leads to undesired rocking movements, is reliably avoided.

In Figure 2, the valve 6 for connecting the two hollow bodies 4, 1 6 is shown in more detail. Figure 2A shows a section similar to Figure 1 and Figure 2B is a plan view. The valve 6 has a valve body 7 and a series of notches 8 on. A valve membrane plate 9 is also provided which, depending on the pressure ratio between the hollow bodies 4, 16, releases or closes the free cross section of the valve 6. The valve membrane plate 9 is connected to the valve body 7 at fastening points 10. In the illustrated embodiment, a return flow bore 3 is integrated in the valve membrane plate 9. The return flow bore 3 can thus be integrated into the valve 6 or formed separately from it, as shown in FIG. 1. The assembly of the damping device 20 according to the invention is facilitated by the integration of the return flow bore 3 in the valve 6. The valve body 7 protrudes somewhat into the hollow body 4 and is fixed there with the catches 8.

FIGS. 3A and 3B each show a section and a top view through the valve 12 for pressure equalization with the surroundings. The valve 1 2 has a series of suction openings 1 1 and an elastic body 1 3. In the event of negative pressure in the hollow body 4, the valve 1 2 is raised into its position shown in FIG. 3a by the elastic body 1 3. As a result, the suction openings 1 1 are released so that the desired pressure equalization with the environment can take place. An overpressure arises in the hollow body 4 under load. As a result, the elastic body 1 3 is deformed and the suction openings 1 1 are closed. If the overpressure in the hollow body 4 exceeds a certain predetermined dimension, the elastic body 1 3 is deformed further, so that the suction openings 11 are released again and the overpressure in the hollow body 4 is reduced. Due to this reduction, the suction openings 1 1 are then closed again. The valve 1 2 thus prevents damage to the damping device 20 and reliably fills it with air again after exceptionally high loads. FIG. 4 shows a horizontal section through a damping device 20 according to the invention in a second embodiment. The damping device 20 according to FIG. 4 is used in particular in the back area of a seat 30. It has an indentation approximately in the middle, so that a user is guided laterally. For the function and mode of operation of this damping device 20, reference is made to the above statements.

FIG. 5 shows a plan view of the second hollow body 4. This hollow body 4 is provided with the decorative upholstery 1 even before the first hollow body 1 6 is fastened. Alternatively, continuous decorative upholstery can also be used, which is attached after the two hollow bodies 4, 16 have been connected. This is shown for example in Figure 4.

The hollow body 4 has a recess 1 4 for inserting the valve 6, which connects the two hollow bodies 4, 1 6 to one another. In the illustrated embodiment, an insert opening 1 5 for the valve 1 2 for pressure equalization with the environment is provided below this recess 1 4.

A sealing ring 1 8 shown in FIG. 6 is used for sealing between the two hollow bodies 4, 1 6. The sealing ring 1 8 is pushed onto the valve body 7 of the valve 6 and is received between the two hollow bodies 4, 1 6 after assembly. An inadmissible leakage of air at this point is thus reliably avoided.

FIG. 7 shows a vertical section through a third exemplary embodiment of a damping device 20 according to the invention. 7 is designed for use in the area of the seat of a seat 30 and has a corresponding shape.

All damping devices 20 are self-supporting and provided with elements (not shown in more detail) for fastening to the seat 30. These elements are designed identically for all damping devices 20 and are attached in the same place. The damping devices 20 can thus be exchanged quickly and adaptation to different boundary conditions can be achieved by using different damping devices.

FIG. 8 schematically shows a view of a seat 30 using the damping device 20 shown in FIG. 7 in a vertical section similar to FIG. 1. The seat surface of the seat 30 is continuously covered with the decorative upholstery. This decorative upholstery 1 is attached after attaching the damping device 20. The seat 30 is then ready for use.

The damping device 20 according to the invention provides rapid pressure build-up and progressive damping under load. High forces can therefore be absorbed. At the same time, unwanted rocking movements are reliably suppressed and a pleasant sitting experience is achieved.

Claims

claims

Damping device for a seat (30), in particular a vehicle seat, with a first deformable hollow body (1 6), which is filled with a resilient filling (2), and a second hollow body (4), which is connected to the first hollow body (1 6) is connected, wherein both hollow bodies (1 6, 4) are filled with a fluid under a certain pressure, characterized in that the two hollow bodies (1 6, 4) are connected to one another via at least one valve (6) which, when a certain overpressure in the first hollow body (1 6) opens with respect to the second hollow body (4) and closes when the pressure falls below this, and that the two hollow bodies (1 6, 4) are connected to one another via at least one backflow bore (3).

Damping device according to claim 1, characterized in that the return flow bore (3) is integrated in the valve (6) or is formed separately from the valve (6).

Damping device according to claim 1 or 2, characterized in that the size of the return flow bore (3) is significantly smaller than the free cross section of the valve (6), in particular less than 50% of the free cross section, preferably less than 30% of the free cross section.

4. Damping device according to one of claims 1 to 3, characterized in that the resilient filling (2) consists of foam.

5. Damping device according to claim 4, characterized in that the resilient filling (2) consists of an open-cell foam.

6. Damping device according to one of the preceding claims, characterized in that the second hollow body (4) with a valve (1 2) is provided for pressure equalization with the environment.

7. Damping device according to one of the preceding claims, characterized in that the second hollow body (4) is designed as a rigid body.

8. Damping device according to one of the preceding claims, characterized in that the volume of the first hollow body (1 6) in the unloaded state is at least 40% of the total volume of the first hollow body (1 6) and the second hollow body (4).

9. Seat, in particular vehicle seat, using a damping device (20) according to one of the preceding claims, characterized in that the damping device (20) is arranged in the region of the seat surface and / or in the region of the backrest.