DE102019211605A1 - Air suspension strut with a ventilated bellows connection - Google Patents

Abstract

Air spring strut (1) for a motor vehicle, comprising an air spring (2) with a shock absorber (3) for the suspension and damping of vibrations of a motor vehicle chassis, the air spring (2) comprising an air spring cover (4) and a rolling piston (5), with between the air spring cover (4) and the rolling piston (5), a rolling bellows (6) made of elastomeric material is clamped pressure-tight, the rolling bellows (6) with the air spring cover (4) and the rolling piston (5) delimiting a pressure chamber (10) filled with compressed air and the rolling bellows (6) rolls on the rolling piston (5) with the formation of a rolling fold (8), the shock absorber (3) comprising a damper tube (13) on which a support means (23) is provided for the rolling piston (5) and the rolling piston (5) is arranged on the support means (23), a bellows (20) being provided to protect the roll fold (8) and a first end (22) of the bellows (20) being attached to the support means (23), wherein in the support means (23) a Belüf processing channel (29) is provided for ventilation of the bellows (20).

Description

The invention relates to an air suspension strut according to the preamble of claim 1.

An air suspension strut like the one from the DE 20 2010 008 057 U1 is known, is arranged between the motor vehicle chassis or a wheel carrier and the motor vehicle body. As a rule, the air suspension strut comprises an air spring and a shock absorber. The air spring fulfills the function of cushioning the wheel, while the shock absorber dampens the vibrations of the wheel or the motor vehicle body.

The air spring consists essentially of an air spring cover, a rolling piston and an elastomeric bellows clamped in between airtight, which delimits a volume-elastic pressure space that is under air pressure. The rolling bellows is enclosed by a sleeve-shaped external guide and rolls on the rolling piston when it is compressed, forming a roll fold.

In order to protect the roll crease from dirt (e.g. dust, sand or stones) when driving, the DE 10 2013 211 644 A1 a ventilated bellows is provided. The bellows is attached on the one hand to the outer guide and on the other hand to the lower end of the rolling piston. At these fastening areas, openings are provided in the bellows, which allow ventilation of the space enclosed by the bellows when the air spring strut is compressed and rebounded. This is necessary so that during the compression and rebound of the air suspension strut, no negative pressure is created in the space enclosed by the bellows.

However, the ventilation openings of the bellows have the disadvantage that dirt is still sucked in and accumulates despite the ventilation. This can damage the roll bellows sooner or later.

It is therefore the object of the invention to provide an air suspension strut with improved ventilation of the bellows.

According to the invention, an air spring strut for a motor vehicle is provided, comprising an air spring with a shock absorber for the suspension and damping of vibrations of a motor vehicle chassis, the air spring comprising an air spring cover and a rolling piston, a rolling bellows made of elastomeric material being clamped in a pressure-tight manner between the air spring cover and the rolling piston, the rolling bellows with the air spring cover and the rolling piston delimiting a pressure chamber filled with compressed air and the rolling bellows rolling on the rolling piston with the formation of a roll fold, the shock absorber comprising a damper tube on which a support means for the rolling piston is provided and the rolling piston is arranged on the supporting means is, wherein a bellows is provided to protect the roll fold, wherein a first end of the bellows is attached to the support means and a ventilation channel is provided in the support means for ventilating the bellows.

This results in the advantage that there is no longer any need for disadvantageous ventilation openings in the bellows, which have to be introduced into the bellows in an additional process step. The ventilation channel can also be provided during the production of the proppant, since the component is brought into its shape by injection molding anyway. Since it is made of a plastic, it is easily possible to introduce the ventilation channel into the support means.

According to a preferred embodiment, the support means comprises a first opening of the ventilation channel, which opens out on a side of the support means that faces the rolling piston. In addition, the support means comprises a second opening of the ventilation channel, which opens out on a side of the support means that faces away from the rolling piston. The support means preferably comprises a channel section of the ventilation channel which connects the first opening to the second opening.

The ventilation channel is characterized in that it consists of an upper opening and a lower opening in the support means. The upper opening opens out on the top of the support means and lies in the bellows space delimited by the bellows and the rolling piston. The lower opening opens out on the underside of the support means and is therefore in the atmosphere surrounding the air spring strut, that is to say in the open.

The two openings are connected to one another via the duct section, so that air from the outside can enter the bellows space and can also flow out again. As a result, when the air suspension strut is compressed and rebounded, no negative pressure is formed in the bellows space.

The channel section is preferably completely covered by the first end of the bellows. This results in a local separation of the environment from the bellows space and the duct section is covered from the outside so that the ventilation duct can realize its air overflow function. The channel section is deliberately designed to be open to the outside, since this does not require any complex shaping in the injection mold and is the easiest to manufacture. The open channel section is then closed by the lower end of the bellows during assembly.

According to a further preferred embodiment, the ventilation channel is provided in an annular flange of the support means. The support means comprises a radially outwardly pointing expansion which is referred to as an annular flange. The lower end of the bellows is attached to this ring flange. At the same time, the ring flange serves as a support surface for the rolling piston, so that the lower end of the piston stands on the ring flange. It is therefore advisable to provide the ventilation channel in this annular flange, since there is sufficient space and material in which the ventilation channel can be introduced.

In a further preferred embodiment, on the side of the support means facing away from the rolling piston, an additional container is arranged which comprises an additional pressure chamber. The function of the support means is expanded in that the additional container is attached below the support means. This includes the additional pressure chamber and thus increases the spring-effective volume of the air spring.

The additional container is preferably materially welded to the support means. Since the additional container is also made of a plastic, it can be welded to the support means by means of corresponding joining surfaces.

The support means preferably comprises a connecting channel which connects the additional pressure space of the additional container with the pressure space of the air spring. The air connection of the pressure space of the air spring with the additional pressure space of the additional container takes place via one or more connecting channels which are introduced into the support means. Such a connection channel opens at the top of the support means and extends through it to the bottom of the support means and thus opens into the additional pressure space of the additional container. Particularly preferably, the connecting channel can be closed via a switching valve attached to the support means. The spring force of the air spring can be changed by means of a switching valve by increasing or decreasing the total volume of the air spring acting on the spring by switching the additional pressure chamber on or off.

The air suspension strut is used in a chassis of a motor vehicle, in particular in an air suspension system.

Further preferred embodiments of the invention emerge from the subclaims and the following description of embodiments with reference to the figures.

• 1 ein erstes beispielsgemäßes Luftfederbein mit einem Stützmittel im Schnitt,
• 2 das beispielsgemäße Luftfederbein der 1 in perspektivischer Ansicht,
• 3 das Stützmittel im Detail,
• 4 ein zweites beispielsgemäßes Luftfederbein mit einem Zusatzbehälter an dem Stützmittel,
• 5 das Stützmittel mit dem Zusatzbehälter im Detail,
• 6 das Stützmittel mit dem Zusatzbehälter in perspektivischer Ansicht, und
• 7 eine Abwandlung des Zusatzbehälters.

Show it

• 1 a first exemplary air suspension strut with a support means in section,
• 2 the exemplary air suspension strut of 1 in perspective view,
• 3 the proppant in detail,
• 4th a second exemplary air suspension strut with an additional container on the support means,
• 5 the proppant with the additional container in detail,
• 6 the support means with the additional container in a perspective view, and
• 7th a modification of the additional container.

The 1 shows a first exemplary air suspension strut 1 consisting of an air spring 2 and an integrated shock absorber 3 , being air spring 2 an air spring cover 4th , a rolling piston 5 and a rolling bellows 6 with an outer guide enclosing these in the form of a sleeve 7th includes. Inside air spring 2 is shock absorber 3 provided, taking shock absorbers 3 a damper tube 13 and a piston rod that can be immersed in this 14th includes, piston positions 14th via a shock mount 15th in the air spring cover 4th is stored.

Air strut 1 fulfills two functional areas, air spring fulfills one 2 the load capacity generation, while shock absorbers 3 is responsible for the linear guide. About fasteners 16 on the air spring cover 4th can air strut 1 be attached on the one hand to a motor vehicle body and on the other hand via a shock absorber eye, not shown, to a wheel carrier of the motor vehicle chassis, whereby the motor vehicle is sprung and damped. This regular installation position of an air suspension strut determines the "top / bottom" orientation.

Air spring 2 includes bellows 6 made of elastomeric material, with roll bellows 6 with air spring cover 4th and rolling piston 5 a pressure-tight and volume-elastic pressure chamber filled with compressed air 10 limited. A tubular roll bellows is used for this 6 with its upper end on the air spring cover 4th and with its lower end on the rolling piston 5 e.g. via clamping rings 11 attached pressure-tight to the connection areas of these air spring connection parts. There is pressure space for setting the spring force 10 via an air connection 17th on the air spring cover 4th can be filled with compressed air. Between the damper tube 13 and rolling piston 5 is a sealant 27 provided to the inside of the rolling piston 5 expanded printing space 10 the air spring 2 to be sealed to the outside.

With relative movements along the longitudinal axis L. of the air suspension strut 1 between air spring cover 4th and rolling piston 5 rolls bellows 6 under Formation of a roll fold 8th on the rolling surface of the rolling piston 5 from. Roll bellows also forms 6 two cardanic folds 9 on the air spring cover 4th which are effective as a cardan bearing. At the same time is roll bellows 6 provided with embedded reinforcements. In the case of comfortable axial bellows in particular, that is to say with reinforcement supports aligned in the axial direction, external guides are used 7th used to reduce the lateral expansion of the rolling bellows 6 to limit. There is external guidance 7th by one in the pressure room 10 provided clamping ring 12 on the bellows 6 pressed.

Damper tube 13 of the shock absorber 3 is inside the rolling piston 5 provided or is from the hollow cylinder-shaped rolling piston 5 Surrounded at least in areas, with rolling piston 5 on a proppant 23 stands. For this purpose forms proppants 23 an annular flange 24 from, on the top of which a lower end 18th of the rolling piston 5 rests. Support is in proppants 23 a support ring 25th inserted, which improves the load-bearing capacity. Support ring 25th lies on a circumferential bead 26th of the damper tube 13 on what proppants 23 on the damper tube 13 is attached. The example is proppant 23 made of a plastic, thermoplastics or thermosets being considered as plastics.

To protect the roll crease from soiling 8th is a bellows 20th provided, which with its upper end 21st at the lower end of the outer guide 7th and with its lower end 22nd on the proppant 23 is attached. The lower end 22nd of the bellows 20th is in a form-fitting manner around the annular flange 24 of the proppant 23 put over or pulled over.

Bellows 20th limited with rolling piston 5 a bellows space 28 , which extends to below the roll fold 8th extends. This means that when the air suspension strut moves in and out 1 no negative pressure in the bellows space 28 arises, the bellows space must be ventilated 28 guaranteed. Ventilation openings in the bellows 20th would have the disadvantage, however, that dirt in the bellows space through the openings 28 arrives and builds up, causing the roll fold 8th can be damaged.

Hence proppants looks 23 for example, a ventilation channel before, which of the following 2 can be found.

The 2 shows the first exemplary air suspension strut 1 from air spring 2 and shock absorbers 3 in perspective view. The bellows 6 is about clamping ring 11 on the air spring cover 4th attached and is by external guide 7th enclosed. About fasteners 16 on the air spring cover 4th air suspension strut can be connected to the vehicle body. The air connection 17th serves to reduce the pressure chamber of the air spring 2 to be filled with compressed air.

The lower area of the air suspension strut 1 is shown open to the connection of the bellows 20th on the proppant 23 and to better illustrate the ventilation of the bellows space (without reference numbers).

Rolling piston 5 lies with its lower end 18th on proppants 23 which is on the damper tube 13 is attached. Bellows 20th is with its upper end 21st at the lower end of the outer guide 7th and with its lower end 20th on the proppant 23 attached. For the lower connection of the bellows 20th is the ring flange 24 of the proppant 23 intended. Not just that, the rolling piston 5 with its lower end 18th on the top of the ring flange 24 stands, but also the lower end 22nd of the bellows 20th is form-fitting on the outside of the ring flange 24 put inside.

A ventilation duct is provided to enable ventilation of the bellows space 29 in the proppant 23 intended. Ventilation duct 29 is used as a recess in the annular flange 24 of the proppant 23 introduced and has a first upper opening 31 to the bellows space and a second lower opening 32 to the environment. Between the two openings 31 , 32 a channel section extends in the circumferential direction along the outer wall of the annular flange 24 . This channel section is from the lower end 22nd of the bellows 20th completely covered or closed.

In the following 3 becomes the proppant 23 with ventilation channel 29 illustrated in more detail.

So shows 3 the proppant according to the example 23 isolated by itself with its ventilation duct 29 . The top opening 31 of the ventilation duct 29 opens into the top of the stepped ring flange 24 and extends perpendicularly on the outer wall of the annular flange 24 . From there, the ventilation duct kinks 29 at a right angle into a horizontal duct section 30th to then in the lower perpendicular opening 32 to flow. Lower opening 32 of the ventilation duct 29 is through a lower ledge 33 on the ring flange 24 educated.

As already described, there is an upper opening 31 in the bellows space, while the lower opening 32 is in the vicinity of the air suspension strut. A duct section is used so that the bellows space is ventilated and the space is separated 30th completely closed or covered by the lower end of the bellows, not shown. Thus is a channel section 30th locked on the outside and it there is a separation of the ventilation duct 29 so its first opening 31 in the "clean" bellows space and its second opening in the "unclean" environment.

Through ventilation channel 29 in the proppant 23 This therefore results in the advantage that ventilation openings in the bellows can be dispensed with. As a result, the costs for the bellows are reduced and dirt is no longer sucked through these openings into the bellows space, which is deposited and damages the roll fold of the air spring. It is much more difficult for dirt particles to pass through the ventilation channel 29 to get into the bellows space.

Like it the 3 It can be seen that there are a large number of such ventilation channels 29 on the proppant 23 intended. So are a first ventilation channel 29 and a second ventilation channel 29 'arranged next to one another, the second ventilation channel 29' being formed mirrored about a vertical axis. On the opposite back of the ring flange 24 two further ventilation channels can be provided, so that a total of four ventilation channels in the support means 23 are introduced, which improve the ventilation of the bellows space.

The 4th shows a second exemplary air spring strut 1 , which is essentially the air suspension strut of the 1 corresponds, so the same reference numbers are used.

The second air suspension strut 1 differs from the first air suspension strut in that between the rolling piston 5 and the damper tube 13 immediately no sealant is provided around the pressure chamber 10 the air spring 2 to limit. But in the proppant 23 is a connecting channel 36 provided to one below the proppant 23 arranged additional container 34 including an additional pressure room 35 with the pressure room 10 the air spring 2 connect to.

Like the proppant 23 and additional container 34 are precisely constructed, is described in the following 5 better described.

That's how it is 5 a section of the second air strut can be seen, which support means 23 with additional container 34 shows in detail.

Proppants 23 includes an inner wall 37 and an outer wall 38 , with inner wall 37 with the damper tube 13 corresponds and support ring 25th houses, by means of which proppant 23 on bead 26th of the damper tube 13 is arranged. In addition, there is between the damper tube 13 and inner wall 27 an internal sealant 39 provided to provide a seal along the damper tube 13 against the atmosphere.

Outer wall 38 of the proppant 23 goes into ring flange 24 of the proppant 23 over, with an insert in the transition area 47 in proppants 23 is introduced to the load-bearing capacity of the annular flange 24 for rolling piston 5 to improve. Depositor 47 can for this purpose be made of a metal, for example steel, or of a duroplast. At the same time there is outer wall 38 with rolling piston 5 in surface contact. In addition, on the outer wall 38 towards the inside of the rolling piston 5 an external sealant 40 provided to provide a seal along the rolling piston 5 to undertake.

In the plastic material of the proppant 23 between its inner wall 37 and its outer wall 38 is a connecting channel 36 brought in. This turns out to be a vertical bypass for the pressure chamber of the air spring to the additional pressure chamber 35 of the additional container 34 represents. An upper opening of the connecting channel 36 opens into the enlarged pressure chamber 10 between the rolling piston 5 and the damper tube 13 . A lower opening of the connecting channel 36 consequently opens into an additional pressure chamber 35 . There can also be several vertical connecting channels in the support means 23 be introduced to facilitate the exchange of air between the pressure chamber of the air spring and the additional pressure chamber 35 of the additional container 34 to increase.

To additional containers 34 below the proppant 23 to be connected to this is a common joining area 41 intended. The inner wall 37 of the proppant 23 extends vertically downwards over bead 26th away and sees a horizontally surrounding inner joining edge 42 in front. The outer wall 38 of the proppant 23 forms below the ring flange 24 radially outwards to an outer joint edge 43 out.

Additional container 34 includes an inner wall 44 which over a floor 46 with an outer wall 45 connected is. At the top is an additional container 34 open. It resembles a pot with an inner passage for the damper tube 13 of the shock absorber. As is the proppant 23 is an additional container 34 made from a plastic, for example from a thermoplastic or a duroplastic.

The connection of the additional container 34 takes place in a materially bonded manner by plastic welding of the corresponding joint areas 41 under an inert atmosphere. So will the inner wall 44 of the additional container 34 to the inner joining edge 42 of the proppant 23 created and the outer wall 45 of the additional container 34 is attached to the outer joint 43 of the proppant 23 created. Then be the corresponding joining surfaces are materially welded together.

Additional container 34 uses the available space below the rolling piston 5 optimally to enlarge the spring-effective pressure chamber of the air spring. Through the additional pressure space 35 in the additional container 34 So the spring-effective pressure chamber of the air spring is enlarged, which leads to a softer suspension. Optionally, the additional pressure chamber 35 via a switching valve on the additional container 34 the pressure chamber of the air spring can be switched on and off by the switching valve opening the connection channel 36 opens or closes.

Together with the functional integration of the ventilation duct for the bellows, a lightweight and cost-effective module for the air suspension strut is made available which combines three essential functions. The first thing is through the proppant 23 with additional container 34 as a common module of the rolling piston 5 supported, with rolling piston 5 via corresponding noses in the proppant 23 this against damper tube 13 is pressed and thus secured against rotation. Second, the bellows connection is made on the annular flange of the proppant 23 realized with simultaneous ventilation through the ventilation channel. Thirdly, additional tank expands 34 the spring-effective pressure chamber of the air spring.

Finally, the 6 and 7th the one with the additional container 34 welded proppants 23 shown in perspective view.

In the 6 is the ventilation duct 29 on the proppant 23 to recognize. The additional container 34 is such that its outer wall 45 is completely closed.

The modification of the additional container 34 in the 7th provides that its outer wall 45 is interrupted in the circumferential direction and in the inner wall 44 transforms. This additional container is shown in cross section 34 with its additional pressure chamber in an approximately horseshoe or U-shape. The recess thus created creates space for attachments of the shock absorber.

List of reference symbols

1

Air strut

2

Air spring

3

Shock absorbers

4th

Air spring cover

5

Rolling piston

6th

Rolling bellows

7th

External guide

8th

Roll fold

9

Cardanic folds

10

Printing room

11

Clamping ring

12

Tension ring

13

Damper tube

14th

Piston rod

15th

Shock mount

16

Fasteners

17th

Air connection

18th

lower end of the rolling piston

19th

Additional spring

20th

Bellows

21st

upper end of the bellows

22nd

lower end of the bellows

23

Proppants

24

Ring flange

25th

Support ring

26th

bead

27

sealant

28

Bellows space

29

Ventilation duct

30th

Channel section

31

first opening of the ventilation duct

32

second opening of the ventilation duct

33

head Start

34

Additional container

35

Additional pressure space

36

Connection channel

37

Inner wall of the proppant

38

Outer wall of the proppant

39

internal sealant

40

external sealant

41

Joining area

42

inner joining edge

43

outer joint edge

44

Inner wall of the additional container

45

External wall of the additional container

46

Bottom of the additional container

47

Depositor

L.

Longitudinal axis of the air suspension strut

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 202010008057 U1 [0002]
• DE 102013211644 A1 [0004]

Claims (10)

Air spring strut (1) for a motor vehicle, comprising an air spring (2) with a shock absorber (3) for the suspension and damping of vibrations of a motor vehicle chassis, the air spring (2) comprising an air spring cover (4) and a rolling piston (5), with between a bellows (6) made of elastomeric material is clamped in a pressure-tight manner between the air spring cover (4) and the rolling piston (5), the rolling bellows (6) with the air spring cover (4) and the rolling piston (5) delimiting a pressure chamber (10) filled with compressed air and the rolling bellows (6) rolls on the rolling piston (5) with the formation of a rolling fold (8), the shock absorber (3) comprising a damper tube (13) on which a support means (23) is provided for the rolling piston (5) and the rolling piston (5) is arranged on the support means (23), a bellows (20) being provided to protect the roll fold (8) and a first end (22) of the bellows (20) being attached to the support means (23), characterized in that in the St ützmittel (23) a ventilation channel (29) for ventilating the bellows (20) is provided. Air suspension strut (1) Claim 1 , characterized in that the support means (23) comprises a first opening (31) of the ventilation channel (29) which opens on a side of the support means (23) which faces the rolling piston (5). Air suspension strut (1) Claim 1 or 2 , characterized in that the support means (23) comprises a second opening (32) of the ventilation channel (29) which opens on one side of the support means (23) which faces away from the rolling piston (5). Air suspension strut (1) Claim 2 and 3 , characterized in that the support means (23) comprises a channel section (30) of the ventilation channel (29) which connects the first opening (31) to the second opening (32). Air suspension strut (1) Claim 4 , characterized in that the channel section (30) is completely covered by the first end (22) of the bellows (20). Air suspension strut (1) according to one of the Claims 1 to 5 , characterized in that the ventilation channel (29) is provided in an annular flange (24) of the support means (23). Air suspension strut (1) according to one of the Claims 1 to 6 , characterized in that an additional container (34) is arranged on the side of the support means (23) facing away from the rolling piston (5) and comprises an additional pressure chamber (35). Air suspension strut (1) Claim 7 , characterized in that the additional container (34) is materially welded to the support means (23). Air suspension strut (1) Claim 7 or 8th , characterized in that the support means (23) comprises a connecting channel (36) which connects the additional pressure space (35) of the additional container (34) with the pressure space (10) of the air spring (2). Motor vehicle comprising an air spring strut (1) according to one of the Claims 1 to 9 .

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