Abstract:
An axle-lifting device for lifting an axle of a vehicle. The axle-lifting device includes a function mechanism for generating a force component in an axle-lifting direction. The function mechanism is configured to generate a first force component for providing a first functionality and a second force component for lifting the axle in the axle-lifting direction.

Description:
THE FIELD OF THE INVENTION 
       [0001]    The present invention relates to an axle-lifting device, a method for lifting an axle and axle assemblies which may be used in vehicles. 
       BACKGROUND INFORMATION 
       [0002]    The axles and axle assemblies of vehicles are designed for a predetermined load. In vehicles having a very high ratio of empty/loaded, the problem encountered during “empty” or “partially loaded” load states is that the actual load on the axles and assemblies is much lower than the design load. This may lead to disproportionate wear on the tires and brake pads, among other things, in relation to the use of the axle, namely the load carried. 
         [0003]    This problem is usually solved by an axle-lifting device, for example, an axle lift, which lifts the axle and parts of the assembly in the “empty” and “partially loaded” states and thus solves the aforementioned problem. The axle lift is a separate component, which has only the purpose of lifting the axle. In more recent modular approaches, an axle lift may also be retrofitted. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the exemplary embodiments and/or exemplary methods of the present invention is to create an improved axle-lifting device, an improved method for lifting an axle and an improved axle assembly. 
         [0005]    This object is achieved by an axle-lifting device as recited herein, a method for lifting an axle as recited herein, and an axle assembly as recited herein. 
         [0006]    The exemplary embodiments and/or exemplary methods of the present invention is based on the idea that axle components or axle assembly components, which are usually present, may be used to lift an axle by slightly modifying the axle components or axle assembly components which are usually present. 
         [0007]    According to the exemplary embodiments and/or exemplary methods of the present invention, all the components which are capable of directly or indirectly generating a force component in the axle-lifting direction according to their task may be considered for this purpose. Thus, a force required to lift the axle may be generated by a force-generating component, which is already present on the vehicle and is also used for other purposes. 
         [0008]    It is advantageously possible for the components, which are used for lifting the axle according to the present invention, to continue to fulfill the task for which they were originally provided. Thus only a few additional components or none at all are necessary for lifting the axle. 
         [0009]    The exemplary embodiments and/or exemplary methods of the present invention creates an axle-lifting device for lifting an axle of a vehicle, having the following features: 
         [0010]    A function mechanism for generating a force component in an axle-lifting direction, the function mechanism being designed to generate a first force component for providing a first functionality and to generate a second force component to lift the axle in the axle-lifting direction. 
         [0011]    According to one embodiment, the function mechanism may be a shock absorber, which is already present. Shock absorbers are usually operated with a fluid and dissipate the energy introduced due to bumps in the road by converting it into heat at a throttle point. Forces are thus generated in the spring compression and spring deflection directions. A set-up and activation of the shock absorber according to the present invention makes it possible to use this shock absorber force to lift the axle. In this way, a component which already exists may be utilized in multiple ways. This allows a separate axle lift to be omitted. 
         [0012]    The present invention also creates a method for lifting an axle of a vehicle, having the following steps: 
         [0013]    Providing a function mechanism for generating a force component in an axle-lifting direction, the function mechanism being designed to generate a first force component to provide a first functionality and to generate a second force component in the axle-lifting direction to lift the axle; and 
         [0014]    Providing a control signal to the function mechanism to generate the second force component. 
         [0015]    The exemplary embodiments and/or exemplary methods of the present invention also creates an axle assembly having the following features: 
         [0016]    A trestle which may be connected to a chassis; 
         [0017]    A suspension arm for accommodating an axle, the suspension arm being movably connected to the trestle; and 
         [0018]    An axle-lifting device as described herein, the axle-lifting device being connected to the suspension arm. 
         [0019]    Exemplary embodiments of the present invention are explained in greater detail below with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  shows a representation of an assembly having an axle-lifting device according to the present invention. 
           [0021]      FIG. 2  shows a representation of another assembly having an axle-lifting device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    In the following description of the exemplary embodiments of the present invention, the same or similar reference numerals are used for the similar elements represented in the various drawings, so a repeat description of these elements is omitted here. 
         [0023]      FIG. 1  shows an axle assembly having an axle-lifting device according to one exemplary embodiment of the present invention. The axle assembly may be connected to a chassis  102  of a vehicle and has a trestle  104  and a suspension arm  106 . Trestle  104  is connected to chassis  102 . One end of suspension arm  106  is rotatably mounted on trestle  104 . The axle assembly may also have a bellows  108 . Bellows  108  is connected to chassis  102  and is designed to absorb a movement of suspension arm  106  in the direction of chassis  102 . For this purpose, bellows  108  may be situated on one end of suspension arm  106  opposite trestle  104 . Suspension arm  106  is designed to accommodate an axle  110 . 
         [0024]    The axle assembly has an axle-lifting device having a function mechanism  122 . According to this exemplary embodiment, the function mechanism is designed as a shock absorber  122 . Shock absorber  122  has a separating piston  124 . Furthermore, a fluid is situated within shock absorber  122 , so that movement of the separating piston  124  may be dampened. Shock absorber  122  is designed to generate at least one force component in an axle-lifting direction H, which points in the direction of chassis  102 . Furthermore, shock absorber  122  may be designed to generate a force component in the opposite direction. 
         [0025]    The force component in the axle-lifting direction may cause the lifting of axle  110  or prevent or retard the lowering of axle  110 . The force component in the opposite direction may cause a lowering of axle  110  or prevent or retard a lifting of axle  110 . Shock absorber  122  may be designed to use the force component in axle-lifting direction H for both lifting of axle  110  and for at least one additional functionality. According to this exemplary embodiment, the additional functionality may include damping or suspension of axle  110 . 
         [0026]    Due to a predetermined pressure distribution and/or fluid quantity distribution within shock absorber  122 , a resting position of the separating piston and thus a height level of axle  110  may be set. A permanent change in the predetermined pressure distribution and/or fluid quantity distribution may cause a displacement of the resting position of separating piston  124 . The force component in axle-lifting direction H may be generated due to the displacement of the resting position. A force component may be generated due to pressure acting on space  126  of shock absorber  122  in particular, resulting in the lifting of axle  110 . Shock absorber  122  may have a valve for applying pressure to space  126 . Alternatively, the valve as well as the necessary force-generating component for the fluid quantity/fluid pressure may also be mounted outside of component  122 . A component which also provides fluidic volumes for other purposes, for example, a manually operable hydraulic pump, which is used to lift the driver&#39;s cab (in a truck) or to lift a roof panel (on a trailer) may also be used as the force generating component. 
         [0027]    The application of pressure to space  126  may take place in response to a supplied control signal. The control signal may be generated by a control device connected to shock absorber  122 . Since the load state is proportional to the fluid pressure in fluid suspensions, there may be direct control of the axle-lifting device. 
         [0028]    The axle assembly shown in  FIG. 1  may be a pneumatic suspension of a truck, a truck trailer or a truck semi-trailer. According to this exemplary embodiment, shock absorber  122  is situated between trestle  104  and suspension arm  106 . Shock absorber  122  is connected to trestle  104  in the vicinity of chassis  102  on the one hand, while on the other hand, it is connected to suspension arm  106  in the vicinity of axle  110 . 
         [0029]      FIG. 2  shows an axle assembly having an axle-lifting device according to another exemplary embodiment of the present invention. The design of the axle assembly corresponds to the design shown in  FIG. 1 . According to this exemplary embodiment, function mechanism  122  is designed as a bellows. Bellows  122  has a separating piston  124  and is provided for damping of axle  110  or chassis  102 . The damping is thus performed with a compressible fluid, in particular using the same medium, which is also used for the suspension. According to the exemplary embodiments and/or exemplary methods of the present invention, bellows  122  may additionally be used for lifting axle  110 . According to the exemplary embodiment illustrated in  FIG. 1 , applying pressure to space  126  results in axle  110  being lifted. 
         [0030]    The assembly shown in  FIG. 2  may be a pneumatic suspension of a truck, a truck trailer or a truck semi-trailer having a pneumatic suspension shock absorber. According to this exemplary embodiment, bellows  122  is situated between chassis  102  and suspension arm  106 . Bellows  122  is connected on the one hand to chassis  102  and on the other hand to suspension arm  106  at one end, which is opposite trestle  104 . 
         [0031]    The exemplary embodiments described here are selected only as examples and may be combined with one another. Instead of the shock absorber described here, the axle-lifting device according to the present invention may also be based on any other spring component, shock absorber component or other component, which may be used as an axle-lifting device in addition to its primary function. 
       The List of Reference Numerals is as Follows: 
       [0032]      102  chassis 
         [0033]      104  trestle 
         [0034]      106  suspension arm 
         [0035]      108  bellows 
         [0036]      110  axle 
         [0037]      122  shock absorber 
         [0038]      124  separating piston 
         [0039]      126  pressure space