DE102012210388B4 - air spring module - Google Patents

Abstract

Air spring module consisting of an air spring (1) and a shock absorber for cushioning and damping vibrations of a motor vehicle chassis, with- an air spring cover (2),- an airtight rolling bellows attached thereto, which at least partially delimits a working space (3) filled with compressed air,- a rolling piston, which is attached to a cylinder tube of the shock absorber and on which the rolling bellows rolls, - a damper bearing (7) which connects a piston rod (4) of the shock absorber to the air spring cover (2) and a supporting piece (8), an elastomer body (10 ) and a damper bearing cover (11), the damper bearing (7) being arranged in the air spring cover (2) and being subjected to ambient pressure on both sides, - a sealing element (13) for sealing the working chamber (3) from the air spring cover (2) and to the Piston rod (4),- an additional spring (5), which is arranged concentrically to the piston rod (4) and is guided in a guide ring (6), which is connected to the air spring cover (2),- the cylinder tube of the shock absorber being attached to a first end is attached to a wheel suspension via a damper fork and has a bore for the piston rod (4) on a second end on one end face, with the end face of the cylinder tube being supported on the auxiliary spring (5) when the air spring module is almost fully deflected, with the damper bearing (7) and the sealing element (13) are provided nested, so that the sealing element (13) protrudes at least partially into the damper bearing (7) in the axial direction, characterized in that the sealing element (13) seals one on the piston rod (4). arranged inner ring (16) and an outer ring (17) arranged sealed in the air spring cover (2), which are connected to each other by means of a rubber element (18) and wherein the outer ring (17) of the sealing element (13) has a circumferential, axial projection ( 19) of the air spring cover (2), which extends in the direction of the damper bearing (7), with the outer ring (17) on a radial lip (20) of the projection (19) and on the guide ring (6) of the auxiliary spring (5) supports.

Description

The invention relates to an air spring module consisting of an air spring and a shock absorber for cushioning and damping vibrations of a motor vehicle chassis, with an air spring cover, an airtight rolling bellows attached thereto, which at least partially delimits a working space filled with compressed air, a rolling piston which is attached to a cylinder tube of the shock absorber and on which the rolling bellows rolls, a damper bearing, which connects a piston rod of the shock absorber to the air spring cover and comprises a supporting piece, an elastomer body and a damper bearing cover, the damper bearing being arranged in the air spring cover and subjected to ambient pressure on both sides, a sealing element for sealing of the working space to the air spring cover and to the piston rod,
an auxiliary spring which is arranged concentrically to the piston rod and is guided in a guide ring which is connected to the air spring cover, the cylinder tube of the shock absorber being attached at a first end via a damper fork to a wheel suspension and at a second end on an end face of a bore for the piston rod, with the end face of the cylinder tube being supported on the auxiliary spring when the air spring module is almost fully deflected, with the damper bearing and the sealing element being provided in a nested manner, so that the sealing element protrudes at least partially into the damper bearing in the axial direction.

1. 1) an der Trennstelle zwischen Arbeitsraum (Druckraum) und Umgebung,
2. 2) vollständig innerhalb des Druckraums und
3. 3) vollständig außerhalb des Druckraums, also in der Umgebung.

Top mounts in passenger cars have the task of filtering out high-frequency excitations - caused by the road surface - and thus avoiding the system-related inertia of the hydraulic vibration damper, which would have a negative effect on driving comfort. This applies to all types of air spring modules. In the case of steel suspension, the top and bottom of the top mount are subjected to the same pressure, ie the ambient pressure of 1 bar absolute. There are several versions of the top mount for air springs:

1. 1) at the point of separation between the work space (pressure space) and the environment,
2. 2) entirely within the pressure chamber and
3. 3) completely outside the pressure space, i.e. in the environment.

The first possible design, in which the damper bearing is subjected to the ambient pressure on the one hand and the air spring pressure on the other, allows the cable of the damper valve to be routed to the outside in the damper piston without a complex, expensive seal due to the arrangement at the point of separation between the pressure chamber and the environment. The disadvantage of this embodiment, however, is that the top of the damper bearing is exposed to the constant ambient pressure and the bottom is exposed to the air spring pressure. As a result, pressure surges are not compensated, which leads to movements of the top mount. These are transferred to the piston rod and lead to uncomfortable driving behavior.

This embodiment also has the disadvantage that the arrangement is relatively long axially. As a result, valuable spring travel can be lost or use can be impossible from the outset due to limited installation space. Another disadvantage is the large number of individual parts, which leads to higher costs, both in terms of the parts production and the assembly effort.

It is also disadvantageous that the long axial extent results in a relatively undetermined pivot point and large distances and deformations during angular movement (gimbals), which in turn is unfavorable for the service life and the lowest possible gimbal rigidity.

As a further embodiment, the damper bearing can be provided entirely within the pressure chamber. However, this design can only be used if the damper adjustment is located outside of the damper, since with a damper valve in the damper piston, the connection cable must be routed through the piston rod to the outside. Sealing this cable and all of its strands is very expensive and therefore very disadvantageous from an economic point of view. Therefore, this version is usually only used if no cable has to be routed to the outside.

A fully arranged outside of the pressure chamber damper bearing, which for example from the EP 1 402 195 B1 is known, the ambient pressure is applied to the upper and lower sides - as with the steel spring version. This has the advantage that no pressure surges act on the damper bearing, which could lead to movements of the piston rod.

• • großer Kolbenstangenhub möglich,
• • sehr geringer Reibungswiderstand,
• • sehr geringer Verschleiß,
• • sehr gute Dichtigkeit,
• • lässt Winkelbewegungen zu,
• • lässt Radialverschiebungen zu und
• • geringe Druckangriffsfläche bei Druckstößen.

That according to EP 1 402 195 B1 well-known damper bearing offers the following advantages:

• • large piston rod stroke possible,
• • very low frictional resistance,
• • very low wear,
• • very good tightness,
• • allows angular movements,
• • allows for radial shifts and
• • Small pressure attack surface in the event of pressure surges.

Due to the position outside the pressure chamber, the piston rod must be guided to the outside and sealed. However, due to wheel forces, it moves several millimeters in the axial direction relative to the spring strut. In addition, considerable transverse and angular movements occur, which is why the seal is complex and therefore expensive. The complexity of the entire damper bearing structure and the high assembly costs are also considered to be disadvantageous.

From the pamphlets JP 2011 - 020 589 A and DE 10 2006 036 248 A1 air spring modules are known in which the damper bearing and the sealing element are provided nested in such a way that the sealing element protrudes at least partially into the damper bearing in the axial direction.

The invention is based on the object of providing an air spring module that is improved in this regard, with a damper mount that is arranged completely outside of the pressure chamber.

The object is achieved according to the invention with an air spring module consisting of an air spring and a shock absorber for cushioning and damping vibrations of a motor vehicle chassis according to the features of claim 1.

The damper bearing and the sealing element are provided in a nested manner, so that the sealing element protrudes at least partially into the damper bearing in the axial direction. This configuration enables a short overall length without sacrificing the stated advantages of the damper bearing arranged outside of the pressure chamber.

According to the invention, the sealing element has an inner ring arranged in a sealed manner on the piston rod and an outer ring arranged in a sealed manner in the air spring cover, which are connected to one another by means of a rubber element. Such a sealing element can be manufactured and installed easily and inexpensively. Furthermore, it has a small pressure contact surface, which minimizes the effects of pressure surges on the movement of the piston rod. Despite movements of the piston rod relative to the strut by several millimeters in the axial direction and transverse and angular movements that occur, the sealing of the working space can be guaranteed.

A simple fixation of the sealing element is also achieved according to the invention in that the outer ring of the sealing element is arranged in a circumferential, axial projection of the air spring cover, which extends in the direction of the damper bearing, with the outer ring on a radial lip of the projection and on the guide ring of the additional spring supports.

The support piece of the damper bearing is preferably designed in the shape of a pot, with the wall extending in the direction of the working space and at the same time protruding at least partially beyond the sealing element in the axial direction. On the one hand, the wall of the supporting piece offers a sufficient fastening surface for the elastomer body and, on the other hand, enables nesting with the sealing element in a simple manner.

According to a further advantageous embodiment of the invention, at least one metal sleeve is vulcanized into the rubber element. The radial rigidity of the sealing element can thus be increased in a defined manner.

Another advantageous embodiment of the invention provides that the inner sleeve and the supporting piece are provided in one piece, which means that the number of components can advantageously be reduced.

• 1 einen Ausschnitt eines ersten Ausführungsbeispiels eines Luftfedermoduls mit Dämpferlager;
• 2 einen Ausschnitt eines zweiten Ausführungsbeispiels eines Luftfedermoduls mit Dämpferlager;
• 3 einen Ausschnitt eines dritten Ausführungsbeispiels eines Luftfedermoduls mit Dämpferlager und
• 4a einen Ausschnitt eines vierten Ausführungsbeispiels eines Luftfedermoduls mit Dämpferlager.

Further features, advantages and application possibilities of the invention emerge from the subclaims and the following description of exemplary embodiments as well as from the drawing. In each case, it shows in a highly schematized form as well as in section:

• 1 a section of a first exemplary embodiment of an air spring module with a damper bearing;
• 2 a section of a second exemplary embodiment of an air spring module with a damper bearing;
• 3 a section of a third exemplary embodiment of an air spring module with a damper bearing and
• 4a a section of a fourth exemplary embodiment of an air spring module with a top mount.

1 shows a section of a first exemplary embodiment of an air spring module, which, as is known, consists of an air spring 1 and a shock absorber for cushioning and damping vibrations of a motor vehicle chassis, which in the motor vehicle is preferably fixed to the body at a first end and to a wheel suspension at a second end. The air spring 1 consists of an air spring cover 2 fixed to the body, a first end of a rolling bellows, not shown, attached thereto airtight with a clamping ring, which at least partially delimits a working or pressure chamber 3 filled with compressed air. A second end of the rolling boot is connected airtight with a rolling piston. The rolling piston, on which the rolling bellows can roll, is connected airtight via an O-ring to a cylinder tube of the shock absorber, wherein the damper fork that can be fastened to the wheel suspension is preferably attached to the cylinder tube. A second end of the cylinder tube has a bore for a piston rod 4 of the shock absorber on one end face, with the end face of the cylinder tube being supported on an additional spring 5 when the air spring module is almost fully deflected, which is arranged concentrically to a piston rod 4 of the shock absorber. The additional spring 5 is guided in a guide ring 6 which is firmly connected to the air spring cover 2 .

A damper bearing 7 arranged in the air spring cover 2, which connects the piston rod 4 of the shock absorber to the air spring cover 2, has the task of filtering out high-frequency excitations - caused by the road surface - and thus avoiding the system-related inertia of the shock absorber, which has a negative effect on driving comfort would.

For this purpose, the damper bearing 7 comprises a support piece 8 made of steel or aluminum with a central bore 9 for the passage of the piston rod 4 and an elastomer body 10, which can be made of rubber, for example. However, other elastically deformable materials can also be used, with polyurethane foam being particularly suitable.

A damper bearing cover 11, which is fastened to the air spring cover 2, for example by means of a snap ring 12, enables the axial prestressing and fixing of the elastomer body 10 in the air spring cover 2.

A sealing element 13, which is described in more detail below, seals the working chamber 3 from the air spring cover 2 and from the piston rod 4, so that the top and bottom sides of the damper bearing 7 are subjected to the ambient pressure. This has the advantage that no pressure surges act on the damper bearing 7, which could lead to movements of the piston rod 4. A connecting cable 14 for adjusting electric damper valves can be routed out of the piston rod 4 without complex sealing measures.

In order to avoid the disadvantages of known damper bearings arranged completely outside of the pressure chamber, the damper bearing 7 and the sealing element 13 are nested so that the sealing element 13 protrudes at least partially into the damper bearing 7 in the axial direction, as shown in FIG 1 is evident. This configuration enables the air spring module to have a short overall length without sacrificing the known advantages of a damper bearing arranged outside of the pressure chamber.

The supporting piece 8 of the damper bearing 7 is pot-shaped for this purpose. Its wall 15 extends in the direction of the working space 3 and projects beyond the sealing element 13 at least partially in the axial direction. The wall 15 of the support piece 8 offers a sufficient fastening surface for the elastomer body 10, which is vulcanized onto the support piece 8, for example, and on the other hand enables nesting with the sealing element 13 in a simple manner.

The sealing element 13 has an inner ring 16 arranged in a sealed manner on the piston rod 4 and an outer ring 17 arranged in a sealed manner in the air spring cover 2 , which are connected to one another by means of a rubber element 18 . As a result, the sealing element 13 can be produced and installed in a simple and cost-effective manner. Furthermore, it has a small pressure contact surface, which minimizes the effects of pressure surges on the movement of the piston rod.

To fix the sealing element 13 in place, the outer ring 17 is arranged in a circumferential, axial projection 19 of the air spring cover 2, which extends in the direction of the damper bearing 7, with the outer ring 17 on a radial lip 20 of the projection 19 and on a radial end face 21 of the guide ring 6 of the additional spring 5 is supported.

The outer ring 17 is sealed to the projection 19 of the air spring cover 2 by means of an O-ring 24 which is provided in a circumferential groove 25 of the outer ring 17 .

The inner ring 16 is sealed against the piston rod 4 by means of an O-ring 22 which is arranged in a circumferential groove 23 in the piston rod 4 .

How out 1 As can further be seen, the inner ring 16 is fixed on the piston rod 4 by a damper nut 27 in contact with a piston rod shoulder 26 and the support piece 8 .

Vent holes 28 in the support piece 8 and recesses 29 in the elastomer body 10 ensure pressure equalization on all sides of the damper bearing 7.

The following exemplary embodiments differ in their basic structure from the first exemplary embodiment according to FIG 1 not, so that only the differences to the other exemplary embodiments are described.

2 shows a section of a second exemplary embodiment of an air spring module. To increase the radial rigidity of the sealing element 13 is how 2 As can be seen, a metal sleeve 30 is vulcanized into the rubber element 18 . Depending on the requirements for the rigidity of the sealing element 13, one or more metal sleeves 30 can be provided in order to increase the rigidity in a defined manner.

According to a 3 In the exemplary embodiment illustrated in detail, the inner ring 16 and the support piece 8 are provided in one piece, as a result of which the number of components can advantageously be reduced.

In order to reduce further components, the sealing element 13 according to the 4 illustrated embodiment is provided as a rubber element 32, which is vulcanized between a circumferential, axial projection 31 of the air spring cover 2 and the piston rod 4. Additional sealing elements and their assembly can thus be omitted. Furthermore, this allows the piston rod 4 to be configured more simply.

Reference List

1

air spring

2

air spring cover

3

working space

4

piston rod

5

auxiliary spring

6

guide ring

7

top mount

8th

supporting piece

9

drilling

10

elastomer body

11

damper bearing cap

12

snap ring

13

sealing element

14

connection cable

15

wall

16

inner ring

17

outer ring

18

rubber element

19

head Start

20

envelope

21

face

22

o ring

23

groove

24

o ring

25

groove

26

Piston rod heel

27

damper nut

28

vent hole

29

recess

30

metal sleeve

31

head Start

32

rubber element

Claims (4)

Air spring module consisting of an air spring (1) and a shock absorber for cushioning and damping vibrations of a motor vehicle chassis, with - an air spring cover (2), - an airtight rolling bellows attached thereto, which at least partially delimits a working space (3) filled with compressed air, - a rolling piston which is attached to a cylinder tube of the shock absorber and on which the rolling bellows rolls, - a damper bearing (7) which connects a piston rod (4) of the shock absorber to the air spring cover (2) and a support piece (8), an elastomer body (10 ) and a damper bearing cover (11), the damper bearing (7) being arranged in the air spring cover (2) and being subjected to ambient pressure on both sides, - a sealing element (13) for sealing the working chamber (3) from the air spring cover (2) and to the Piston rod (4), - an additional spring (5), which is arranged concentrically to the piston rod (4) and is guided in a guide ring (6), which is connected to the air spring cover (2), - the cylinder tube of the shock absorber being attached to a first end is attached to a wheel suspension via a damper fork and has a bore for the piston rod (4) on a second end on one end face, with the end face of the cylinder tube being supported on the auxiliary spring (5) when the air spring module is almost fully deflected, with the damper bearing (7) and the sealing element (13) are provided nested, so that the sealing element (13) protrudes at least partially into the damper bearing (7) in the axial direction, characterized in that the sealing element (13) seals one on the piston rod (4). arranged inner ring (16) and in the air spring cover (2) arranged sealed outer ring (17), which are connected to each other by means of a rubber element (18) and wherein the outer ring (17) of the seal element (13) is arranged in a circumferential, axial projection (19) of the air spring cover (2), which extends in the direction of the damper bearing (7), the outer ring (17) being on a radial lip (20) of the projection ( 19) and on the guide ring (6) of the auxiliary spring (5). air spring module claim 1 , characterized in that the supporting piece (8) of the damper bearing (7) is cup-shaped, the wall (15) extending in the direction of the working space (3) and the sealing element (13) at least partially protruding in the axial direction. air spring module claim 1 or 2 , characterized in that in the rubber element (18) at least one metal sleeve (30) is vulcanized. Air spring module according to any of the preceding Claims 1 until 3 , characterized in that the inner ring (16) and the support piece (8) are provided in one piece.

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