DE102020207241A1 - Air suspension device with a rolling piston and an interchangeable shell - Google Patents

Abstract

Air spring device (1) for a motor vehicle, comprising an elastomeric rolling bellows (6) which is fastened in a pressure-tight manner between an air spring cover (4) and a rolling piston (5), as a result of which a variable-volume pressure space (7) filled with compressed air is delimited, the rolling piston (5 ) comprises an interchangeable shell (20) on which the rolling bellows (6) rolls while forming a roll fold (8), the interchangeable shell (20) comprising a first and a second shell piece (21; 22), which by means of a first and a second snap connection ( 25; 26) are connected to one another, a first groove (23) for the first snap connection (25) and a second groove (24) for the second snap connection (26) being provided on the rolling piston (5), the first snap connection ( 25) engages positively in the first groove (23) and the second snap connection (26) engages positively in the second groove (24).

Description

The invention relates to an air spring device for a motor vehicle according to the preamble of claim 1.

Air spring devices, which are used as air springs or air spring struts, are clamped between a chassis part and a body section of a motor vehicle. They have a rolling bellows which is fastened between a cover and a rolling piston. The air spring is under an internal overpressure during operation and the rolling bellows rolls when the spring moves, forming a roll fold on the outer surface of the rolling piston. To limit expansion, the rolling bellows is enclosed by a sleeve-shaped external guide.

The spring behavior of the air spring can be determined by the surface area of the rolling piston. The spring stiffness is influenced by its shape or the surface on which the rolling bellows rolls. A modular principle has been established so that not every rolling piston has to be designed and shaped for a specific application. A rolling piston is provided on which an interchangeable shell is placed. The interchangeable shell is provided in a detachable manner and can be provided in a wide variety of forms. Thus, with one and the same rolling piston, the desired spring stiffness can be set using a wide variety of interchangeable shells.

This procedure is an example from the document DE 10 2011 085 323 A1 known. An interchangeable shell is pushed onto the base body so that the interchangeable shell defines the outer contour of the piston skirt. However, the axial pushing on of the interchangeable shell in the assembly process has shown to be disadvantageous.

For example, it is more advantageous to mount the interchangeable shell onto the base body, coming from the radial outside. This is from the document JP 2018-100707 A known to produce the interchangeable shell from two separate shell parts and to plug them into one another laterally on the base body.

It is therefore the object of the invention to provide an air spring device with a rolling piston and an interchangeable shell, the attachment of the interchangeable shell to the rolling piston being improved.

The object on which the invention is based is achieved with the features of the independent patent claim. Preferred embodiments emerge from the subclaims.

According to the invention, an air spring device for a motor vehicle is provided, comprising an elastomeric rolling bellows which is fastened in a pressure-tight manner between an air spring cover and a rolling piston, whereby a volume-variable pressure chamber filled with compressed air is limited, the rolling piston comprising an interchangeable shell on which the rolling bellows rolls while forming a roll fold, wherein the interchangeable shell comprises a first and second shell piece, which are connected to one another by means of a first and a second snap connection, a first groove for the first snap connection and a second groove for the second snap connection being provided on the rolling piston, the first snap connection being positively connected in the first groove and the second snap connection engage positively in the second groove.

The two shell pieces of the interchangeable shell are advantageously connected to one another by two snap connections and lock in a form-fitting manner in specially provided grooves in the rolling piston. This ensures that the interchangeable shell is securely held on the rolling piston. The interchangeable shell can no longer twist on the rolling piston.

A preferred embodiment provides that the first shell piece has a multiplicity of engagement wings which are designed to engage in an undercut of the second shell piece in a form-fitting manner. The engagement wings of one shell piece in operative connection with the undercut of the other shell piece ensure that the two shell pieces cannot be released so easily. Due to the fact that the snap connections engage in the grooves, the shell pieces expand radially outward when pulled off. As a result, the engagement wings of one shell piece engage even more strongly in the undercut of the other shell piece, so that an extremely secure form fit is effective here. Since several engagement wings are provided on each joining edge of the shell pieces and each joining edge also has an undercut, the construction ensures that the two shell pieces hold each other.

According to a further preferred embodiment, it is provided that the snap connections span a respective form pressure angle which is greater than a form take-up angle of the respective groove. The provision of the snap connections with a slightly larger shape angle than the shape angle of the grooves also ensures a better hold of the interchangeable shell on the rolling piston.

The snap connections are preferably provided in an axially aligned manner. This leaves Mount the interchangeable shell coming from the radial outside onto the rolling piston and assemble it.

In a further preferred embodiment, a flange for axially supporting the two shell pieces is provided on the rolling piston in the circumferential direction. The flange ensures that the formwork pieces do not fall down and are held axially in position.

It is preferably provided that the rolling piston has a clamping shaft for fastening one end of the rolling bellows, the first and / or the second groove extending essentially from the clamping shaft to the flange. The engaging surface for the snap connection is enlarged by an elongated groove, so that the shell pieces are better held in the groove.

The rolling piston is preferably made of a metal or a plastic. The interchangeable shell is preferably made of a plastic. An interchangeable shell made of plastic enables simple shaping of the rolling surface for the roll fold and is also elastically deformable in such a way that the shell pieces can be inserted onto the rolling piston or into the grooves.

If the air suspension device according to the invention is combined with an integrated shock absorber, it is an air suspension strut in which the interchangeable shell is also used.

The air spring device is used in an air spring system of a motor vehicle.

Further preferred embodiments of the invention emerge from the following description of an embodiment with reference to the figures.

• 1 eine beispielsgemäße Luftfedereinrichtung mit einem Abrollkolben und einer Wechselschale,
• 2 den Abrollkolben mit Schalenstücken der Wechselschale in Explosionsansicht,
• 3a bis d ein Schalenstück in verschiedensten Ansichten, und
• 4a und b den Abrollkolben mit Schalenstücken im Eingriff.

Show it:

• 1 an exemplary air suspension device with a rolling piston and an interchangeable shell,
• 2 the rolling piston with shell pieces of the interchangeable shell in an exploded view,
• 3a until d a piece of shell in various views, and
• 4a and b the rolling piston engaged with shell pieces.

the 1 shows an exemplary air suspension device 1 comprising 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 bellows 6th includes. Inside air spring 2 is shock absorber 3 provided, taking shock absorbers 3 a damper tube 17th and a piston rod that can be immersed in this 18th includes.

Rolling bellows 6th consists of elastomeric material and is limited by an air spring cover 4th and rolling piston 5 a pressure-tight and volume-variable pressure chamber filled with compressed air 7th . A tubular roll bellows is used for this 6th 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 12th attached to the connection areas of these air spring connection parts. With relative movements along a longitudinal axis L. the air suspension device 1 between air spring cover 4th and rolling piston 5 rolls bellows 6th with the formation of a roll fold 8th on an exchangeable shell 20th which serves as a rolling surface. Interchangeable shell 20th is detachable on the rolling piston 5 plugged. Due to the shape of the interchangeable shell 20th becomes the spring behavior of air springs 2 influenced. In addition, roll bellows forms 6th another crease 9 on the air spring cover 4th the end. wrinkle 9 is effective as a cardan bearing. Rolling bellows 6th is also provided with embedded reinforcements. Its reinforcements are arranged in an axial and / or cross position.

Furthermore, one is the rolling bellows 6th at least partially enclosing external guide 10 intended. This is achieved by an inside on the bellows 6th attached tension ring 13th held. External guide 10 limits the lateral expansion of the bellows 6th , especially if it is thin-walled.

The filling of the pressure chamber 7th takes place via an air connection on the air spring cover 4th . In the air spring cover 4th a channel is introduced or drilled, which leads from the air connection into the interior of the air spring 2 leads. The air connection is an air spring 2 can be filled with a certain amount of compressed air, whereby its spring force is also adjusted.

To protect the bellows from soiling 6th and especially its roll fold 8th is a protective bellows 11th intended. This is with its upper end at the lower end of the outer guide 10 and with its lower end at the lower end of the rolling piston 5 attached. The attachment of the protective bellows 11th can be positive or non-positive.

Air suspension device 1 causes two functional areas. Air spring 2 takes care of the load capacity generation, while shock absorbers 3 is responsible for the linear guide. As a result, the motor vehicle is sprung and dampened. On the one hand there is an air suspension device 1 via air spring cover 4th connected to a body section of a motor vehicle and on the other hand via a not shown Damper eye of the shock absorber 3 connectable to a wheel carrier of the motor vehicle. This regular installation position of the air suspension device 1 determines the "top / bottom" orientation.

Rolling piston 5 , which is made of a metal or a plastic, is shaped as a hollow cylinder and standing on a support ring 14th of the damper tube 17th arranged sealingly. At the upper free end of the piston rod 18th is a shock mount 15th attached. Shock mount 15th comprises an elastomer body in which the support piece is at least partially embedded. Support piece is at the upper end of the piston rod 18th fixed. Shock mount 15th is in a warehouse 16 of the air spring cover 4th arranged. Stock taking 16 of the air spring cover 4th is cup-shaped and in a core area of the air spring cover 4th intended. It includes a side wall and a floor. In the bottom of the warehouse 16 or the air spring cover 4th is a through hole for the piston rod 18th intended. There is also a stop buffer below the floor 19th arranged to the compression travel of the damper tube 17th to limit and when the stop in the air spring cover 4th to reduce the forces introduced. Air spring cover 4th is made of a plastic material, for example a thermoplastic or a thermosetting plastic. A version of the air spring cover 4th made of a metal, for example aluminum or steel, is also possible.

In the 2 becomes a rolling piston 5 with an exemplary interchangeable shell 20th Mistake. Interchangeable shell 20th is a sleeve-shaped part, which consists of two shell pieces 21 and 22nd is composed. Interchangeable shell 20th can also be assembled from several shell pieces. The inner wall of the interchangeable shell 20th lies on the rolling piston 5 at. The outer wall of the interchangeable shell 20th represents the rolling surface for the roll fold of the roll bellows. Its external shape or shape influences the spring behavior of the air suspension device.

Interchangeable shell 20th is through a central and axial cut in the two shell pieces 21 and 22nd divided. This allows exchangeable shell 20th Coming from the radial outside on the rolling piston 5 be plugged. This is easier to assemble than a one-piece interchangeable shell from above on the rolling piston 5 to push. However, it is then necessary to use the two shell pieces 21 and 22nd firmly on the rolling piston 5 connect to. Snap connections are used for this 25th and 26th provided, by means of which the two shell pieces 21 and 22nd at their axial joining edges 32 be put together. Every shell piece 21 and 22nd has two joining edges 32 on, the shape of which is complementary to the corresponding joining edge 32 of the other shell piece is.

To ensure a better hold of the interchangeable shell 20th or the shell pieces 21 and 22nd are to be taken care of at the rolling piston 5 a first groove 23 and a second groove 24 intended. Groove 23 and 24 run axially in the rolling piston 5 brought in. Groove 23 and 24 the respective snap connections are provided for this 25th or 26th to record. In groove 23 the first snap connection engages 25th form-fitting. In groove 24 engages the second snap connection 26th form-fitting. It also has a rolling piston 5 a circumferential flange 27 on. flange 27 is intended for the two shell pieces 21 and 22nd axially supported. Furthermore includes rolling piston 5 a clamp shaft 28 for fastening one end of the rolling bellows. Grooves preferably extend 23 and 24 from the clamp shaft 28 up to the flange 27 . This creates an elongated form fit between the groove and the snap connection, which ensures that the interchangeable shell is properly secured against twisting 20th on the rolling piston 5 cares.

In the 3a until c becomes shell piece 21 shown in various representations. The snap connections are made through an undercut 30th in which engagement wing 29 intervenes. this is the 3a at one of the joining edges 32 to see which shell piece 21 show from above. At the joining edge 32 of shell piece 21 is an engaging wing 29 intended. This protrudes from the radially inside to the outside and protrudes slightly. Low engagement 29 protrudes from a shaped surface 31 of the shell piece 21 emerged. This shaped surface 31 has to an imaginary center point of the shell piece 21 a smaller radius than the inner wall of the shell piece 21 . Molding surface 31 thus protrudes inwards. Furthermore is at the joining edge 32 in the outer area of the undercut 30th intended.

In the 3b which shell piece 21 shows in side view are engagement wings 29 , Undercut 30th and joining surface 31 see again. Only one joining edge 32 has been given the corresponding reference numerals for the sake of simplicity. Of the 3b it can be seen that a large number of engagement wings 29 at the joining edge 32 are provided. These are at certain distances from each other at the joining edge 32 arranged. The undercut 30th and also the joining surface 31 however, extend over the entire length of the joining edge 32 . The undercut 30th is located in the outer area of the joining edge 32 so that the outwardly protruding engagement wings 29 can engage in the undercut of the opposite joining edge. On both joining edges 32 of shell piece 21 there is engagement wing 29 and an undercut each 30th . The same applies to the other shell piece.

3c shows shell piece 21 in perspective view. At the joining edge 32 is the in Radius or diameter smaller forming area 31 clearly. The intervention wings stand from it 29 which are set up to engage in the undercut of the other shell piece.

the 3d shows another alternative engagement wing 29 of the first shell piece 21 on. Instead of a flat wing, two individual arms are used.

With the 4a and b the operating state is shown when the two shell pieces 21 and 22nd engaged on the rolling piston 5 are located. From above you can see how the first shell piece 21 and second shell piece 22nd are plugged together. On the right side of the 4a is the first snap connection 25th and on the left the second snap connection 26th to see.

The detail C is in the 4b shown in more detail. On a rolling piston 5 are first shell piece 21 and second shell piece 22nd by means of the first snap connection 25th tied together. First snap connection 25th is in the first groove 23 positively recorded. The form fit is created by the respective shaped surfaces of the joining edges (both without reference symbols), which are in the 3a until c have been described in more detail. The joining edges and shaped surfaces of the respective shell piece 21 and 22nd lie to form the first snap connection 25th butt against each other. Due to the fact that the joining surfaces have a smaller diameter than the inner wall of the shell pieces 21 and 22nd or the interchangeable shell, they protrude into the first groove 23 into it. This creates the form-fitting connection from the first snap connection 25th with the first groove 23 .

Preferably, the two mold surfaces jointly span a mold pressure angle b which is larger than a mold receiving angle a which through the first groove 23 is opened. This ensures that the first snap connection is held securely 25th in the first groove 23 taken care of. The form pressure angle is preferably b 90 °. The mold receiving angle is preferably a 70 °.

The first snap connection 25th arises from the fact that the respective engagement arms of the two shell pieces 21 and 22nd in the mutual undercut of the two shell pieces 21 and 22nd intervention. The secure fixation of the interchangeable shell on the rolling piston 5 is caused by the joining surfaces of the two snap connections. Should one or both shell pieces 21 and 22nd move radially outwards due to an external influence, then the joining surface located in the groove represents a resistance. If, for example, a second shell piece 22nd solves, the joining surface slides on the inclined surface of the groove and thereby expands the diameter of the second shell piece 22nd on. Through this widening of the diameter, the engagement wings of the shell piece grip 22nd even more in the undercut of the first shell piece 21 a, so that the loosening of the second shell piece 22nd is prevented. This form-locking mechanism holds the two shell pieces 21 and 22nd firmly together in operation and in position at the same time. Vibrations and movements of the air spring during operation are considered to be external influences. Critical for the fixation of the interchangeable shell on the rolling piston 5 that is, the fully sprung state of the air spring when the roll fold of the roll bellows barely covers the interchangeable shell. Then the pressure forces of the roll fold only have a limited effect on the interchangeable shell. So if the interchangeable shell is free, a secure fixation must be ensured. This is done using the snap connections in the grooves of the rolling piston.

The structural representation of the first snap connection 25th in the first groove 23 , which in the 4b shown and described also applies to the second snap connection 26th in the second groove 24 .

List of reference symbols

1

Air suspension device

2

Air spring

3

Shock absorbers

4th

Air spring cover

5

Rolling piston

6th

Rolling bellows

7th

Printing room

8th

Roll fold

9

wrinkle

10

External guide

11

Protective bellows

12th

Clamping ring

13th

Tension ring

14th

Support ring

15th

Shock mount

16

Stock taking

17th

Damper tube

18th

Piston rod

19th

Stop buffer

20th

Interchangeable shell

21

first shell piece

22nd

second shell piece

23

first groove

24

second groove

25th

first snap connection

26th

second snap connection

27

flange

28

Clamp shaft

29

Engaging wing

30th

Undercut

31

Molding surface

32

Joining edge

a

Form pressure angle

b

Form receiving angle

L.

Longitudinal axis

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 102011085323 A1 [0004]
• JP 2018100707 A [0005]

Claims (10)

Air spring device (1) for a motor vehicle, comprising an elastomeric rolling bellows (6) which is fastened in a pressure-tight manner between an air spring cover (4) and a rolling piston (5), as a result of which a variable-volume pressure space (7) filled with compressed air is delimited, the rolling piston (5 ) comprises an interchangeable shell (20) on which the rolling bellows (6) rolls while forming a roll fold (8), the interchangeable shell (20) comprising a first and a second shell piece (21; 22), which by means of a first and a second snap connection ( 25; 26) are connected to one another, characterized in that a first groove (23) for the first snap connection (25) and a second groove (24) for the second snap connection (26) are provided on the rolling piston (5), the first snap connection (25) engages positively in the first groove (23) and the second snap connection (26) engages positively in the second groove (24). Air suspension device (1) Claim 1 , characterized in that the first shell piece (21) has a plurality of engagement wings (29) which are designed to engage in an undercut (30) of the second shell piece (22) in a form-fitting manner. Air suspension device (1) Claim 1 or 2 , characterized in that the snap connections (25; 26) span a respective form engagement angle (b) which is greater than a form take-up angle (a) of the respective groove (23; 24). Air suspension device (1) according to one of the Claims 1 until 3 , characterized in that the snap connections (25; 26) are provided axially aligned. Air suspension device (1) according to one of the Claims 1 until 4th , characterized in that a flange (27) for axially supporting the two shell pieces (21; 22) is provided on the rolling piston (5) in the circumferential direction. Air suspension device (1) Claim 5 , characterized in that the rolling piston (5) has a clamping shaft (28) for fastening one end of the rolling bellows (6), the first and / or the second (23; 24) groove extending essentially from the clamping shaft (28) to extend to the flange (27). Air suspension device (1) according to one of the Claims 1 until 6th , characterized in that the rolling piston (5) is made of a metal or a plastic. Air suspension device (1) according to one of the Claims 1 until 7th , characterized in that the interchangeable shell (20) is made of a plastic. Air suspension device (1) according to one of the Claims 1 until 8th , characterized in that it comprises an air spring (2) with an integrated shock absorber (3). Motor vehicle comprising an air spring device (1) according to one of the preceding claims.

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