Air spring damper unit

Abstract

The invention relates to an air spring damper unit (1) for the suspension and damping of a wheel suspension system (2) on the chassis (3) of a motor vehicle, having an air spring bellows (4) which generates the spring force, is filled with a compressible gas, in particular compressed air, and is connected to a first supporting body (6) which transmits the supporting force and bears in a supporting manner against a second supporting body (7) which is supported on the chassis (3) of the motor vehicle, and having a telescopic shock absorber (5) which is assigned to the air spring bellows (4) and the piston rod (5b) of which passes through the interior space, filled with compressed air, of the air spring bellows (4) and is connected via elastic connecting means (12) to the first supporting body (6). In order to considerably simplify such an air spring damper unit in terms of production, without impairing the function, the invention proposes that the first supporting body (6) consists in one piece of rigid material (metal or plastic) and is supported on the second supporting body (7) so as to be rotatable about an axis running in the supporting direction, wherein the displacement between the first supporting body and the second supporting body is designed in such a way that it supports both axially directed forces and radially directed forces.

Description

[0001] Air spring damper unit

[0002] The invention relates to an air spring damper unit for the suspension and damping of a wheel suspension on the chassis of a motor vehicle, comprising an air spring bellows filled with a compressible gas, in particular compressed air, which generates the spring force and is connected at one end to a first support body transmitting the support force, which rests against a second support body which is supported on the chassis of the motor vehicle, and comprising a telescopic shock absorber associated with the air spring bellows, the piston rod of which passes through the compressed air-filled interior of the air spring bellows and is connected to the first support body via elastic connecting means.

[0003] Such air spring damper units are known in various embodiments according to the prior art, e.g. from DE 10 2009 036 554 B4. A fundamental problem with such air spring damper units is to design the connecting device between the air spring damper unit and the chassis of the motor vehicle in such a way that, on the one hand, the support forces generated by the air spring bellows and the damping forces generated by the telescopic shock absorber are reliably, i.e., as directly as possible, transmitted into the chassis of the motor vehicle, and, on the other hand, sufficient rotational mobility of the connecting device is achieved, particularly when the air spring damper unit is to be used on steered axles of the motor vehicle.

[0004] The aforementioned DE 10 2009 036 554 proposes achieving the required rotational flexibility by making the first support body, which closes off the bellows and transmits the spring force of the bellows, partially composed of an elastically compliant rubber material or a urethane foam. However, the use of such elastic materials in this critical area leads relatively quickly to fatigue fractures and leaks in the elastic material, which, in addition to the support and torsional loads, must also withstand the pressure of the air spring bellows.

[0005] It is therefore an object of the invention to improve the air spring damper unit of the type mentioned at the outset with regard to long-term stability, sealing and functionality.

[0006] To solve this problem, the invention proposes, starting from the air spring damper unit of the type mentioned above, that the first support body consists of rigid material (metal or plastic) and is rotatably supported on the second support body about an axis extending in the support direction, wherein the displacement between the two support bodies is designed in such a way that it supports both axially directed forces and radially directed forces.

[0007] The invention's proposed method of manufacturing the first support body from a rigid material and the specific design of the connection between the two support bodies eliminates the need to use sensitive elastic materials such as rubber or urethane foam for this first support body. This alone significantly increases the long-term durability of this connection between the air spring damping unit and the vehicle chassis. A further advantage is that the support forces of the air spring are transferred to the second support body, which is supported on the vehicle chassis, without any interruption caused by spring-like flexion. Finally, it is particularly advantageous that the air space of the air spring can be sealed airtight by using the rigid first support body as the air spring seal, without the need for dynamic seals.

[0008] A suitable embodiment of the air spring damper unit according to the invention provides that at least one support bearing for supporting axially directed forces and at least one support bearing for supporting radially directed forces are arranged between the two support bodies.

[0009] Alternatively or additionally, it may be advantageous to use a support bearing with a conical support surface for the rotatable displacement between the two support bodies, which supports both axial and radial forces.

[0010] It is also expedient that the first support body has a centrally located installation cavity for receiving the elastic connecting elements between the end of the piston rod of the telescopic shock absorber and the first support body.

[0011] In this way, the rigid first support body serves simultaneously as a safe and protected accommodation place for the elastic connecting means by which the piston rod of the telescopic shock absorber is connected to the first support body, and also for the direct introduction of the damping forces of the telescopic shock absorber into the first support body.

[0012] To secure the elastic connecting means between the end of the piston rod of the telescopic shock absorber and the first support body in the installation cavity of the first support body, these connecting means are expediently vulcanized into this installation cavity.

[0013] Alternatively, a removable seat ring can be arranged on the inner circumference of the installation cavity of the first support body, through which the elastic connecting elements of the telescopic shock absorber's piston rod are fixed in the installation cavity. This facilitates the assembly and / or disassembly of the elastic connecting elements between the first support body and the end of the telescopic shock absorber's piston rod, if necessary.

[0014] Furthermore, the extension travel of the telescopic shock absorber is limited by a stop buffer, which is supported directly or indirectly by the first support body. This provides additional protection against hard impacts that can be exerted on the first support body by the cylindrical part of the telescopic shock absorber during extreme compression of the air spring.

[0015] A particularly advantageous embodiment of the air spring damper unit according to the invention provides that the first support body has a hollow pin on its side facing the second support body. This pin projects centrally through the second support body and an installation opening located in the chassis of the vehicle. The pressure-tight sealable cavity of this pin connects to the interior of the air spring bellows via the installation cavity for the elastic connecting elements of the telescopic shock absorber's piston rod. This hollow pin advantageously provides access to the interior of the air spring bellows of the air spring damper unit for any necessary venting or pressurization. Furthermore, it ensures constant pressure equalization between the cavities above and below the elastic connecting elements between the telescopic shock absorber's piston rod and the first support body.

[0016] The hollow pin is advantageously provided at its free end with a removable, airtight cover that conceals an access point through the pin's cavity, leading to the connecting elements between the telescopic shock absorber's piston rod and the first support body. This access point makes it particularly advantageous to reach the mounting interface between the telescopic shock absorber's piston rod and the first support body without disassembling the entire assembly, even with the cover removed.

[0017] In a first embodiment of the invention, to connect the entire air damper-spring unit to the vehicle chassis, the hollow pin of the first support body is provided with a thread on its outer circumference. A support nut can be screwed onto this thread, rotatably securing the first support body of the air damper unit in the installation opening of the vehicle chassis. This support nut, together with the pin, which is an integral part of the first support body, ensures a sufficiently stable and simultaneously sufficiently rotatable mounting of the first support body, and thus of the entire assembly, on the vehicle chassis, with the first support body simultaneously holding the second support body in position.

[0018] As an alternative to the aforementioned type of connection of the air spring damper unit to the chassis of the vehicle, other embodiments of the invention provide that the hollow pin of the first support body is provided on its outer circumference with a snap ring which rotatably supports the pin of the first support body on the second support body, while the second support body is separately fixed to the chassis of the motor vehicle by means of several fastening screws.

[0019] To prevent the transmission of rebound forces, rebound bearings are provided at suitable locations in all embodiments of the invention, namely between the fastening nut and the chassis of the motor vehicle in the first embodiment and between the snap ring and the second support body in the further embodiments.

[0020] To prevent short-stroke, audible, or perceptible vibrations (NVH) from being transmitted between the components of the air spring damper unit and the vehicle chassis, insulating layers against NVH are provided between the second support body and the vehicle chassis. Such insulating layers against NVH can, of course, also be provided elsewhere at suitable locations between the air spring damper unit and the vehicle chassis.

[0021] Several embodiments of the invention are explained in more detail below with reference to the drawing. The drawing shows:

[0022] Figure 1: Schematic representation of the arrangement of a first embodiment of an air spring damper unit according to the invention between the chassis and the axle of a motor vehicle;

[0023] Figure 2: Schematic representation of a vertical section through the connection area between the air spring damper unit and the chassis of the motor vehicle, circled in Figure 1 and designated by reference numeral A;

[0024] Figure 3: Schematic representation of the arrangement of a second embodiment of an air spring damper unit according to the invention between the chassis and the axle of a motor vehicle;

[0025] Figure 4: Schematic representation of a vertical section through the connection area between the air spring damper unit and the chassis of the motor vehicle, which is circled in Figure 3 and labelled A.

[0026] Figure 5: Similar to Figure 4, a vertical section through the connection area between the air spring damper unit and the chassis of the motor vehicle in a third embodiment with a differently designed displacement of the two support bodies relative to each other.

[0027] The corresponding parts of the embodiments of the invention described below are each designated by the same reference numerals in the figure description.

[0028] In Figures 1 and 3, the air spring damper unit according to the invention is designated in its entirety by reference numeral 1. This air spring damper unit 1 is connected at the bottom to the axle 2 of a motor vehicle and at the top to the chassis 3 of this motor vehicle in a manner resistant to tension and compression. Figures 2, 4, and 5 show in detail how the upper end of the air spring damper unit 1 is connected to the chassis 3 of the motor vehicle.

[0029] The main components of the air spring damper unit 1 are a compressed air-filled bellows 4, which generates the supporting spring forces, and a telescopic shock absorber 5 passing through the bellows 4, which generates the damping forces that dampen the spring forces and has a cylinder part 5a and a piston rod 5b.

[0030] The bellows 4 is connected at its underside via a clamping connection 4a in an airtight manner to the upper end of the cylinder part 5a of the telescopic shock absorber 5, and at its upper side via a clamping connection 4b in an equally airtight manner to a first support body 6, which transmits the support forces generated by the bellows 4 upwards towards the chassis 3 of the vehicle. Above the first support body 6, an annular, second support body 7 is arranged, which transmits the support forces generated by the bellows 4 from below upwards to the chassis 3 of the vehicle.

[0031] The first support body 6 is formed in one piece and consists of a rigid material, for example, metal or plastic. Furthermore, the first support body 6 is rotatably supported on the second support body 7 about an axis extending in the support direction. In the embodiments shown in Figures 2 and 4, two support bearings 8 and 9 are provided between the two support bodies 6 and 7 to support axially directed forces, and a support bearing 10 is provided to support radially directed forces. In the embodiment shown in Figure 5, a support bearing 10a with conical bearing surfaces is provided instead of the support bearing 10. This support bearing supports both axial and radial forces. If necessary, such a support bearing 10a with conical bearing surfaces can also, with appropriate design, perform the support function between the two support bodies 6 and 7 on its own.

[0032] The one-piece, first support body 6 is provided centrally with an installation cavity 11 for receiving elastic connecting elements 12 between the end of the piston rod 5b of the telescopic shock absorber 5 and the first support body 6. A removable support 13 is arranged on the inner circumference of this installation cavity 11, by which the elastic connecting elements 12 of the piston rod 5b are fixed in the installation cavity 11. This support 13 also serves to support a stop buffer 14 surrounding the piston rod 5b of the telescopic shock absorber 5, which limits the insertion travel of the piston rod 5b of the telescopic shock absorber 5 in the event of excessive impact loads.

[0033] The one-piece first support body 6 further comprises a hollow pin 15 on its side facing the second support body 7, which projects centrally through the second support body 7 and an installation opening 3a located in the chassis 3 of the motor vehicle. The cavity of the pin 15 is connected to the interior of the air spring 4 via the installation cavity 11 for the elastic connecting elements 12 of the piston rod 5b of the telescopic shock absorber 5, thus allowing the air spring 4 to be pressurized or depressurized with compressed air via the pin 15 as required.

[0034] Furthermore, the pin 15 is provided at its free end with a removable, airtight sealable cover 16, which covers an assembly access (indicated by the arrow X) running through the cavity of the pin 15 to the connecting means 12 between the piston rod 5b of the telescopic shock absorber 5 and the first support body 6.

[0035] In the embodiment shown in Figures 1 and 2, the pin 15 of the first support body 6 is provided with a thread 15a on its outer surface to secure the entire air spring damper unit to the chassis 3 of the vehicle. A support nut 17 is screwed onto this thread. This support nut 17 holds the first support body 6, and thus the entire air spring damper unit assembly, in position on the chassis 3 of the vehicle without hindering rotation of the pin 15 relative to the chassis 3.

[0036] In the embodiments shown in Figures 3, 4, and 5, the pin 15 of the first support body 6 is held in position by a snap ring 17a applied to the pin 15, unlike in the embodiment shown in Figures 1 and 2. This does not impede the rotation of the pin 15, and thus of the first support body 6, relative to the second support body 7. To secure the overall assembly to the chassis 3 of the vehicle, the second support body 7 is fastened to the chassis 3 of the vehicle in these embodiments using several screws 18 and nuts 19.

[0037] Furthermore, all embodiments of the air spring damper unit shown in the drawing are provided with rebound bearings 20, which are intended to prevent rebound forces from being transmitted from the first support body 6 to the chassis 3 during vehicle operation. In the embodiment shown in Figures 1 and 2, these rebound bearings 20 are located between the support nut 17 and the chassis 3 of the vehicle. In the embodiments shown in Figures 3, 4, and 5, this rebound bearing 20 is located between the snap ring 17a and the second support body 7 of the air spring damper unit 1.

[0038] Finally, in all embodiments of the air spring damper unit 1 shown in the drawing, suitable NVH isolating elements 21 are arranged wherever short-stroke movement and NVH (Noise, Vibration, Harshness) can occur in different load directions. In the embodiment shown in Figures 1 and 2, such NVH isolating elements 21 are located between the rebound bearing 20 and the support nut 17, as well as between the chassis 3 of the vehicle and the support body 7. In the embodiments shown in Figures 3, 4, and 5, an NVH isolating element 21 is located between the rebound bearing 20 and the support body 7.

[0039] The above description clearly shows that in the assembly area of ​​the new air spring damper unit, a particularly large number of functions have been combined in a single component, namely the specially designed first support body 6, which brings great advantages in terms of manufacturing technology.

[0040] List of reference signs

[0041] Air spring damper unit;

[0042] Steerable axle;

[0043] Chassis of the motor vehicle; 3a Installation opening in the chassis;

[0044] Air spring bellows; 4a clamping connection; 4b clamping connection;

[0045] Shock absorber; 5a Cylinder shock absorber; 5b Piston rod shock absorber; first support body; second support body;

[0046] Support bearings (axial forces);

[0047] Support bearings (axial forces);

[0048] support bearings (radial forces); a Support bearing with cone-shaped support surfaces thanks

[0049] Installation cavity; elastic fasteners;

[0050] Support ring;

[0051] Stop buffer;

[0052] Pin; 15a thread;

[0053] Lid;

[0054] Support nut; 17a Snap ring;

[0055] 18 screws;

[0056] 19 nuts;

[0057] 20 rebound bearings;

[0058] 21 NVH insulating bodies;

[0059] X Assembly access;

Claims

Patent claims 1.) Air spring damper unit (1) for the suspension and damping of a wheel suspension (2) on the chassis (3) of a motor vehicle, comprising an air spring bellows (4) generating the spring force and filled with a compressible gas, in particular compressed air, which is connected to a first support body (6) transmitting the support force and which bears against a second support body (7) which is supported on the chassis (3) of the motor vehicle, and comprising a telescopic shock absorber (5) associated with the air spring bellows (4), the piston rod (5b) of which passes through the compressed air-filled interior of the air spring bellows (4) and is connected to the first support body (6) via elastic connecting means (12), characterized in that the first support body (6) is made in one piece of rigid material (metal or plastic) and is rotatably mounted on the second support body (7) about an axis extending in the support direction.wherein the displacement between the first support body and the second support body is designed in such a way that it supports both axially directed forces and radially directed forces. 2.) Air spring damper unit (1 ) according to claim 1 , characterized in that at least one support bearing (8 and / or 9) for supporting axially directed forces and at least one support bearing (10) for supporting radially directed forces are arranged between the two support bodies (6,7). 3.) Air spring damper unit (1 ) according to claim 1 , characterized in that a support bearing with a conical support surface (10a) is arranged between the two support bodies (6,7) which supports both axial and radial forces. 4.) Air spring damper unit (1 ) according to one of claims 1-3, characterized in that the first support body (6) has a centrally located installation cavity (11 ) for receiving the elastic connecting means (12) between the end of the piston rod (5b) of the telescopic shock absorber (5) and the first support body (6). 5.) Air spring damper unit (1) according to claim 4, characterized in that the elastic connecting means (12) between the end of the piston rod (5b) of the telescopic shock absorber (5) and the first support body (6) are vulcanized into the installation cavity (11) of the first support body (6). 6.) Air spring damper unit (1 ) according to claim 4, characterized in that a removable support (13) is arranged on the inner circumference of the installation cavity (11 ) of the first support body (6), by which the elastic connecting means (12) of the piston rod (5b) of the telescopic shock absorber (5) are fixed in the installation cavity (11 ). 7.) Air spring damper unit according to one or more of claims 1-6, characterized in that the insertion path of the telescopic shock absorber (5) is limited by a stop buffer (14) which is supported directly or indirectly on the first support body (6). 8.) Air spring damper unit according to one or more of claims 1-7, characterized in that the first support body (6) has a hollow pin (15) on its side facing the second support body (7), which projects centrally through the second support body (7) and an installation opening (3a) located in the chassis (3) of the motor vehicle and whose pressure-tight sealable cavity is connected to the interior of the air spring (4) via the installation cavity (11) for the elastic connecting means (12) of the piston rod (5a) of the telescopic shock absorber (5). 9.) Air spring damper unit (1 ) according to claim 8, characterized in that the hollow pin (15) is provided at its free end with a removable, airtight sealable cover (16) which covers an assembly access (X) extending through the cavity of the pin (15) to the connecting means (12) between the piston rod (5a) of the telescopic shock absorber (5) and the first support body (6). 10.) Air spring damper unit (1 ) according to claims 8 or 9, characterized in that the hollow pin (15) of the first support body (6) is provided on its outer circumference with a thread (15 a) onto which a support nut (17) can be screwed, which rotatably fixes the first support body (6) of the air spring damper unit (1 ) in the installation opening (3a) of the chassis (3) of the motor vehicle. 11.) Air spring damper unit (1 ) according to claims 8 or 9, characterized in that the hollow pin (15) of the first support body (6) on its outer circumference is provided with a snap ring (17a) which rotatably secures the pin (15) of the first support body (6) to the second support body (7), which is separately fixed to the chassis (3) of the motor vehicle by several screws (18,19). 12.) Air spring damper unit (1 ) according to claim 10, characterized in that a rebound bearing (20) is arranged between the support nut (17) and the chassis (3) of the motor vehicle. 13.) Air spring damper unit (1 ) according to claim 11 , characterized in that a rebound bearing (20) is arranged between the snap ring (17 a) and the second support body (7). 14.) Air spring damper unit (1 ) according to one or more of claims 1 - 13, characterized in that NVH isolating elements (21 ) are arranged wherever short-stroke movement NVH (Noise, Vibration, Harshness) can occur in the mounting area of ​​the air spring damper unit (1 ) on the chassis (3) of the motor vehicle.

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