SI8210421A8 - Bandable membrane for air springs - Google Patents

Description

Swivel diaphragm for air springs

TECHNICAL FIELD

The invention relates to the field of air springs and within it to the field of swiveling membranes.

In the international classification of patents, the object of the invention is classified in class F 16 F 9/02.

TECHNICAL PROBLEM

Starting from a double cone-shaped, air-spring swivel membrane equipped with at least two interconnecting fibers, the invention is based on the problem of how to rearrange the membrane in order to achieve a dominant interaction between the tensile stress of the cord structure and the reduction the pressure of the latter in order to obtain a favorable and soft suspension in the future on the basis of the reinforcing effect, without causing any damage to the deformation, without the need for an additional separate outer jacket or extra insert (gurt).

BACKGROUND OF THE INVENTION

It is known that the swiveling membrane of the air spring starts to heart. The amount of pressure exerted upon filling it with the inside of the spring is therefore changed depending on whether it is a compression or a stretching of the spring. During use, due to the deformation of the membrane or the hysteresis of the rubber, part of the physical part of the folding and deformation is converted to heat. From this point of view, great importance is attached to the thickness of the membrane wall, because for a thicker membrane wall, the heat generation due to the part of folding and deformation is more intense than in the case of thinner ones.

- Further dependence can be analyzed during the longitudinal axis dimension. cross-section and intensity of heating. Under the same conditions and with the same internal pressure, the diaphragm will be smaller in diameter and / or smaller in length. diaphragm with smaller air space, more heated.

Understandably, the deformation of the air spring membranes is also noticeably affected by the path conditions. Membranes are subjected to thousands of pressures and stretches per hour on an average-quality lane. Statistical experiments have confirmed that air spring membranes have been subjected to 6.5 x 10® folding cycles under variable path conditions, speeds and loads after 50,000 km, meaning that the membrane must withstand a multiple of this value during its service life. During this spring action, the cord fibers, which are concerned with the strength, are subjected to tension and pressure in the membrane wall. However, compressive loads are very harmful for cord fibers.

On the other hand, there is a tendency that vehicle manufacturers generally require, in addition to providing the suspension, that the air suspension is suitable for lifting the relevant suspension. A further requirement relates in particular to the transport in large quantities of light, vibration-sensitive loads, when the vehicle is practically not fully loaded and when one of the axles (for vibration damping reasons) is raised while driving, thereby that even under extreme spring conditions, approximately the same spring properties are achieved. For many motor vehicles, trailers, tractor units, etc. the use of air springs was at the forefront, since uniquely better spring characteristics could be obtained in this way. Similarly, the air spring system is advantageously used for silo vehicles, tank vehicles, etc. , as this not only improves the quality of the suspension while driving empty, but also spares the whole vehicle. Furthermore, the wheels can be lifted in unladen condition.

It is often the case that the spring air pressure drops to a lower value during the operation of motor vehicles. During transport (by ship, on the line), the vehicle also experiences a case where there is no overpressure in the spring. In this state, due to the lifting of the vehicle and thereby relieving the air spring in question, the pressure inside the diaphragm is lower than the atmospheric pressure, which results in a negative curvature in the swivel diaphragm, which can lead to harmful deformations when placing the vehicle on its wheels and of cavities.

A similar critical condition occurs in the garage position when changing the wheel, therefore, wherever the body suddenly rises, because this causes reduced overpressure and high volume in the membrane.

We find that the profile of a normally made swellable membrane changes in extreme cases, bends under repeated load and can collapse.

External reinforcements have already been suggested to eliminate these phenomena, e.g. metal coat. However, the solution did not produce the desired results, since the coat was able to slip off the membrane and therefore could not perform its function.

Is AT-B-340 209 is a known solution for reducing the adverse effects described above under one or more material inserts, between or above them, that is inserts forming diamonds with their stacked fiber systems at least in one or more further inserts, which are fixed or attached to the first-mentioned insert and whose fiber system distributes said fiber diamonds to the fiber triangles, are provided in the mantle section area of the cylindrical portion of the membrane. This solution (diaphragm insert) leads to a given membrane stiffness in the given sections, reducing the size of the deformation and the adverse effects.

DE-B-2 759 433 discloses a roll-up air spring diaphragm which, when fitted, assumes the shape of a double cone, with the conicity of the truncated cones being different. However, the document does not show the design of the membrane in a non-built state. With this known solution, different conical formations are formed under the influence of the outer jacket and the two spring pistons, and this solution changes according to the current value of the suspension by the relative movement of the metal parts. In this case, they have shapes or. the design of metal parts and their positions is crucial. The performance of the membrane itself is of secondary importance; it is supposedly cylindrical.

DESCRIPTION OF THE PROBLEM SOLVING WITH EXAMPLE

The technical problem stated above is solved by a swivel membrane of a predefined type by varying the diameter of the hollow body of the membrane along the factories in the non-pressurized state

i.s. such that, based on the lower and upper flanges of the swivel membrane, the profile of the double truncated cone is determined by increasing in varying value, and that the swivel membrane comprises at least two inserts containing interconnected fibers and for which the value of the angle of the cord changes continuously along the factories of the hollow body profile .

The cord diameter at the maximum diameter is 25 ° to 40 ° and from there it rises in one direction to 40 ° -50 ° and in the other to 50 ° -60 °.

The angle enclosed by a straight line running parallel to the longitudinal axis of the hollow body and touching the factory at the largest diameter, and the elongated mantle line of the respective cone, at the upper cone is 1 ° to 5 ° and twice as much at the lower cone.

The height of the membrane corresponds to 0.5 to 2.5 times its diameter.

The solution according to the invention is based on the realization that by modifying the profile of the swivel membrane on the basis of the mutual support effect of the double cone and with the resulting angle of the cord, the membrane stiffens and protects against deformation by analogy with the ratio of the ribbed plate to the smooth one.

The invention is further concretized on the basis of a preferred embodiment presented in the accompanying drawings in which Fig. 1 shows a swivel membrane in the triggered, i.e. Fig. 2 is the same in the unloaded state, only in the axonometric representation and in the loaded state in which the lower part of the membrane is wrinkled.

The diaphragm of the invention is characterized in the ground state (without overpressure) by varying diameters along the factory, with diameters emanating from the lower or lower ones. the upper flanges, to varying degrees with each other, determine the profile of the double truncated cone.

The reinforcement system consists of at least two inserts containing interconnecting fibers, in which the cord, i.e. the angle enclosed by the tangent passing through the observed point of the membrane on a plane perpendicular to the axis of the membrane, with cord fibers, constantly changing and occupying along the membrane (forming) of the membrane, proceeding from the largest diameter D, where the angle of the cord is 25 to 40 °, values 40-45 ° in one direction and values 50-60 ° in the other direction.

As can be seen from FIG. 1, the flexible shell 1 of the retractable air spring diaphragm consists of an upper hollow portion 2, which is essentially designed as a truncated cone, and a lower hollow portion 3, which is also designed essentially like a truncated cone, the hollow portions being 2, 3 at their peripheral edges 2 ', 3' equal to one another and at the same time the largest diameter D and at these edges 2 ', max

3 'interconnected into an integral single shell 1 designed as a flexible body 1' preferably made of rubber reinforced with cord inserts 4, 5 inserted (during manufacture) into the flexible body 1 '.

The 4 ', 5' cord inserts 4, 5 intersect each other, respectively. housed in a flexible body 1 'and are connected to one another and to the body 1' as such by the surrounding rubber body mass 1 '.

The density of the _i_ cord is greatest at the diameter D and _fflax and its surroundings and downstream of flange 2, 3. 2.

Taper of the hollow part 2 is determined as the angle between the parallel to the axis xx of the membrane extending tangent T and tvornico (tvorilko) of the hollow part 2, tapered shape of the hollow part 3 is determined by the angle of ^RAEC same tangent T and tvornico (tvorilko) of the hollow part 3, wherein is angle = 1 to 5 °, angle f = 2 to 10 ° and ^ ₂ = 2.

The cord fibers 4 ', 5' at maximum diameter D are surrounded by a perpendicular to the xx axis of the membrane as = 25 ° - 40 °, with the angle 06 .. increasing continuously up to 40 ° - 50 ° in the direction of the flange 2 of the hollow part 2. direction to the flange 3 of the hollow part 3 to a value of 50 ° - 60 °. The height H of the shell 1 is 0.5 to 2.5 D and the height h. hollow part 2 is less than the height h _{2 of} hollow part 3.

The base material of the swivel membrane can be natural or artificial rubber. The cylindrical strip is made of artificial silk, polyamide, fiberglass or steel.

The preferred membrane profile described and the changing structural value of the reinforcement inserts along the factories influence a simple but useful way of operating the membrane, thereby reducing the fatigue of the swivel body of the membrane, while increasing the resistance to the adverse effects of extreme conditions, all the mentioned advantages can be achieved without additional inputs or. reinforcement jacket and without increasing the wall thickness.

When the membrane is compressed and the spring deforms, the diameter increases only to a certain extent, with a smaller diameter increase in the non-rotating surface and a more stable position in the unloaded state. No harmful wrinkles or deformations occur.

A further advantage of the retractable membrane according to the invention is that it significantly reduces the adverse compressive load, since the tensile load prevails. At the same time, the relatively small thickness of the membrane wall is prevented by the bending and the deformation caused by the heat and its harmful effects.

As the diameters of the swivel diaphragm change continuously along the factory of the profile of the swivel membrane, an extremely favorable reinforcement is achieved, the corners appearing in the reinforcing pads also change, resulting from the maximum diameter in both directions being asymmetrical.

In this way, the scope of the air springs can be significantly expanded. The swivel diaphragm according to the invention for air springs can be used in a variety of motor vehicles, from the bus to the fifth wheel tractor, providing optimum suspension and its own oscillating number and operating lever without the need for a special jacket, belt or any other auxiliary element.

Claims (4)

A swivel 'air spring diaphragm designed as a double cone and comprising at least two interconnecting fibers, characterized in that the diameter (D) varies along the factories, proceeding from the lower flange (3) and the upper flange ( 2) shells (1), increasing to a mutually different extent, and that the value of the angle (Ofr) of the cord fibers (5 ') changes continuously along the factories of the shell profile (1), with the angle (ObJ) of the cord fibers (5') increasing from the largest mean diameter (D) in both directions towards the flanges (2, 3). m a x A swivel membrane according to claim 1, characterized in that the angle (C ^ ^) of the cord at a maximum diameter (D) is 25 ° to 40 ° and then increases upwards to 40 ° to 50 ° and down to 50 ° to 60 ° . A swivel membrane according to claim 1 or 2, characterized in that the angle (ffl of which is enclosed by the longitudinal axis (xx) of the shell (1) is parallel and the tangent line (T) and ΓΠ3Χ extend the mantle line at the largest diameter (D). each cone, at the upper part (2) fr = 1 ° - 5 ° and at the lower part (3) A swivel membrane according to one or more of the claims 1 to 3, characterized in that the height (H) of the shell (1) corresponds to 0.5 - 2.5 times its maximum diameter (D).