BELLOWS AIR SPRING

Description

[0001] The invention relates to a bellows air spring with at least one belt ring, wherein the bellows air spring can be tilted about a rotation axis.

[0002] Bellows air springs with two or more folds have a waist-shaped constriction between the folds. This constriction is formed by a reinforcement ring, which ensures that the elastic rubber bellows does not balloon when pressure is applied. The reinforcement ring is referred to as the belt ring.

[0003] A symmetrical design of the folds – relative to the central cross-sectional plane – ensures symmetrical force distributions in the flexible bellows wall during operation with internal pressure. During axial deformation, the two or more folds "automatically" distribute proportionally across the bellows length, provided the opposing connecting parts are arranged symmetrically to each other. The range of possible axial deformation is limited by the block height during retraction, i.e., the height resulting from the sum of the thicknesses of the compressed bellows walls and the belt rings, as well as the heights of the connecting parts, and during extension by the maximum stretch of the textile reinforcement.

[0004] Bellows air springs are ideal for applications where, upon actuation, the mounting surfaces move along a curved path, so that the opposing mounting surfaces are inclined at varying angles to each other. These are, for example, applications where the two connecting surfaces are connected via a rotation axis. The larger the fold, the greater the possible angulation. A bellows air spring with several folds arranged in series ("two-fold" or "three-fold bellows") can, in turn, achieve many times the angulation of a single-fold bellows. However, in the following, only bellows air springs with at least two folds and at least one belt ring will be considered.

[0005] Such air springs are disclosed, for example, in DE 126 48 78 B or DE 69 61 34 22 T2.

[0006] DE 126 48 78 B discloses a bellows air spring in which the metallic belt rings are designed as separate components. DE 69 61 34 22 T2 describes an embodiment in which the metallic reinforcement consists of several wound wires embedded directly in the elastomer of the bellows. The belt ring is therefore not a separate component.

[0007] If the connecting parts of the bellows air spring are not displaced parallel during operation, i.e. if they are angled or tilted, the bellows air spring may buckle.

[0008] Buckling is a malfunction that can lead to non-specification-compliant operation, for example, by exceeding the specified installation space or by shifting the direction of force due to the lateral offset of the belt ring, resulting in forces outside the specification. Lateral offset of a belt ring during retraction can also increase the block dimension.

[0009] In the cases listed here, increased wear or even complete failure of the bellows air spring usually occurs.

[0010] Therefore, there are approaches to preventing the bellows air spring from buckling. For example, DE 457 626 A discloses a simple solution in which one of the belt rings is intended to prevent the bellows air spring from buckling by means of articulated link plates that are hinged to the vehicle frame. However, such a solution is unsatisfactory.

[0011] TheFig. 3a - 3c shows the kinematics of a bellows air spring according to the state of the art from DE 475 626 A.

[0012] If the belt ring guidance described there were to be achieved by means of a linkage 3.7 on the rotation axis 3.6 of the bellows connecting parts 3.4 and 3.5, this would prevent buckling. But as in Figuren 3b und 3c As can be seen, the bellows 3.1 could not assume its naturally curved longitudinal axis 3.9. The center point 3.3 of the belt ring 3.2 would be shifted by the amount d1 or d2 relative to the curved longitudinal axis 3.9. The articulation of the belt ring ensures that, with a symmetrical structure of positions 3.4 and 3.5, the angles are: γ1 = ½ x α1 or γ2 = ½ x α2

[0013] In the case of spreading to maximum extension, as in Fig. 3c As shown, the usable stroke of the bellows is reduced by the amount d2 when the belt ring is "pushed out".

[0014] The object of the invention was to create a bellows air spring for kinematic applications with tilting, which can still be operated in accordance with specifications and reliably even under unfavorable constellations when the connecting parts are tilted, by reliably preventing buckling.

[0015] This task is solved by the fact that the belt ring or, in the case of several belt rings, the belt rings are each linked by means of a lever, whereby the linkage axis of rotation of the respective lever deviates from the axis of rotation of the bellows air spring and in the case of a bellows air spring with two folds and one belt ring, it is defined by the intersection point of two fictitious auxiliary lines, namely on the one hand a first auxiliary line which, in the initial position of the bellows air spring, runs perpendicular to the main axis of the bellows air spring and, as seen in the axial direction, centrally through an adjacent bellows fold, in the case of a bellows air spring with three folds and two belt rings, it is defined by the intersection points of three fictitious auxiliary lines, namely on the one hand a second and a third auxiliary line which, in the initial position of the bellows air spring, each run perpendicular to the main axis of the bellows air spring and, as seen in the axial direction, centrally through the respective outer bellows folds, with a fourth fictitious auxiliary line which runs parallel to the main axis of the bellows air spring through the axis of rotation of the bellows air spring.

[0016] Due to such a linkage, the articulated belt ring or the articulated belt rings each describe a circular path, so that their centers always lie on the main axis of the bellows air spring, even in a tilted state and thus a curved main axis of the bellows air spring.

[0017] An example of the invention is explained in more detail below with reference to the drawing. It shows Fig. 1a - 1c a bellows air spring with two folds and a belt ring and a linkage according to the invention, Fig.2a - 2b a bellows air spring with three folds and two belt rings with linkages according to the invention and Fig. 3a - 3c a bellows air spring with state-of-the-art kinematics.

[0018] In the Fig. 1a 1 shows a bellows air spring 1 according to the invention with a belt ring 2 in its initial position. The belt ring 2 has a center point 3, which here lies on the main axis 13 of the bellows air spring 1. The bellows air spring 1 has two connecting parts, namely an upper part 4 and a lower part 5, which are firmly and airtightly connected to the adjacent fold of the bellows air spring 1. The connecting parts 4 and 5 are also each connected to parts of a unit (not shown in detail) that are to be sprung against one another and are only symbolized here in principle by a rod assembly 14. The unit can be, for example, a motor vehicle body. Each fold of the bellows air spring 1 has a height H. The bellows air spring 1 can be tilted about a rotation axis 6.The belt ring 2 is articulated by means of a lever 7 to the assembly part associated with the lower part 5 of the bellows air spring 1. The lever 7 is rotatably mounted about a rotation axis 10. The rotation axis 10 is defined by the intersection of an auxiliary line 11, which runs perpendicular to the main axis 13 centrally through the fold associated with the lower part of the bellows air spring 1, and an auxiliary line 12, which runs parallel to the main axis 13 through the rotation axis 6 of the bellows air spring. In this illustration, the rotation axis 6 and the rotation axis 10 are perpendicular to the plane of the drawing.

[0019] In the Fig. 1b the bellows air spring 1 is shown in a compressed, tilted state. The bellows air spring 1 now has a curved main axis 9. The upper part 4 and lower part 5 of the bellows air spring 1 now form a tilt angle α1, which is created by the imaginary extension of the connecting planes of the upper part 4 and lower part 5 at the intersection point 8.1 or by the angulation of the upper part 4 relative to the vertical. For the tilt angle γ1 of the belt ring 2 relative to the original horizontal position, γ1 ≠ ½ x α1 applies here, which is determined by the different positions of the axes of rotation 6 and 10. The deviation between the two angles is small, however, and is compensated for by the elasticity of the folds of the bellows air spring 1.

[0020] In the Fig. 1c the bellows air spring 1 is shown in its extended, tilted state. It now has a main axis 9 that is curved in the opposite direction to the compressed state. Here, too, the upper part 4 and lower part 5 form a tilt angle α2, which is created here by the imaginary extension of the connecting planes of the upper part 4 and lower part 5 at the intersection point 8.2. The tilt angle γ2 of the belt ring 2 relative to the original horizontal position is also γ2 ≠ ½ x α2, which is also determined by the different positions of the axes of rotation 6 and 10. Here, too, the deviation between the two angles is small and is also compensated for by the elasticity of the folds of the bellows air spring 1.

[0021] In the Fig. 2a 1 shows a bellows air spring 101 according to the invention with two belt rings 112 and 122 in its initial position. The bellows air spring 101 has an upper connecting part 104 and a lower connecting part 105 as well as a main axis 133. The upper part 104 and the lower part 105 are each assigned to a component to be sprung, not shown in detail here, wherein the component is essentially symbolized by a linkage 140. The upper part 104 and the lower part 105 can be tilted relative to one another via a rotation axis 106. The belt ring 112 is articulated by a lever 117 about a rotation axis 110 to the component assigned to the upper part 104, and the belt ring 122 is articulated by a lever 127 about a rotation axis 120 to the component assigned to the lower part 105.The rotation axes 110 and 120 are each defined by the intersection of two fictitious auxiliary lines, namely the auxiliary line 111, which runs perpendicular to the main axis and centrally to the fold of the bellows air spring 101 assigned to the upper part 104, with the auxiliary line 132, which runs parallel to the main axis 133 and through the rotation axis 106 of the bellows air spring 101, and the auxiliary line 121, which runs perpendicular to the main axis and centrally to the fold of the bellows air spring 101 assigned to the lower part 105, with the auxiliary line 132.

[0022] In the Fig. 2bThe three-fold bellows air spring 101 according to the invention is shown tilted by the tilt angle α1. The upper part 104 and lower part 105 of the bellows air spring 101 form a tilt angle α1, which is formed by the imaginary extension of the connecting planes of the upper part 104 and lower part 105 at the intersection point 108 or by the angulation of the upper part 104 relative to the vertical. The angle β1 formed between the upper part 104 and the belt ring 123 and the angle δ1 formed between the lower part 105 and the belt ring 133 are of equal size, although β1 ≠ ½ α1 Λ δ1 ≠ ⅓ α1. Here, too, this irregularity is compensated for by the elasticity of the folds of the bellows air spring 101. List of reference symbols (part of the description)

[0023] 1, 101 Bellows air spring 2, 112, 122 Belt ring 3, 113, 123 Center points of the belt rings 4, 104 Upper part of the bellows air spring 1, 101 5, 105 Lower part of the bellows air spring 1, 101 6, 106 Axis of rotation of the bellows air spring 1, 101 7, 117, 127 Feedback lever 8.1, 8.2, 108 Points of intersection of the connecting parts 9, 109 Curved main axis 10, 110, 120 Axes of rotation of the feedback levers 11, 111, 121 Fictitious auxiliary lines perpendicular to the main axis 12, 132 Fictitious auxiliary lines parallel to the main axis 13, 133 Main axis of the bellows air spring 1, 101 14, 140 rods, aggregate parts

Claims

1. Convoluted bellows air spring (1, 101) having at least one belt ring (2, 112, 122), wherein the convoluted bellows air spring (1, 101) is tiltable about a pivot axis (6, 106), characterized in that the belt ring (2, 112, 122), or if there are a number of belt rings (2, 112, 122) the belt rings (2, 112, 122), is or are respectively articulated by means of a lever (7, 117, 127), wherein the articulating pivot axis (10,110,120) of the respective lever (7, 117, 127) differs from the pivot axis (6, 106) of the convoluted bellows air spring (1, 101), and - in a convoluted bellows air spring (1, 101) having two folds and a belt ring (2, 112, 122), the intersection of two fictitious auxiliary lines (11, 12) namely defines a first auxiliary line (11) which, in the starting position of the convoluted bellows air spring (1, 101), is perpendicular to the main axis (13) of the convoluted bellows air spring (1, 101) and, as seen in the axial direction, runs centrally through an adjacent convoluted bellows fold, - in a convoluted bellows air spring (1, 101) having three folds and two belt rings (2, 112, 122), the intersections of three fictitious auxiliary lines (110, 120, 132) namely defines a second auxiliary line (110) and a third auxiliary line (120) which, in the starting position of the convoluted bellows air spring (1, 101), are each perpendicular to the main axis (132) of the convoluted bellows air spring (1, 101) and, as viewed in the axial direction, run centrally through the respective outer convoluted bellows folds, - with a fourth fictitious auxiliary line (12, 132) which runs parallel to the main axis (13, 13) of the convoluted bellows air spring (1, 101) through the pivot axis (6, 106) of the convoluted bellows air spring (1, 101).