Patent Publication Number: US-2021164533-A1

Title: Vibration damper with adjustable damping force

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national stage of Application No. PCT/EP2018/080419 filed Nov. 7, 2018. Priority is claimed on German Application No. DE 10 2017 222 232.8 filed Dec. 8, 2017 the content of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a vibration damper with an adjustable damping force. 
     2. Description of Related Art 
     In a vibration damper with an adjustable damping valve device arranged at an outer side on an outer cylinder, there is often a problem of structural space as a result of an associated large cross section in a region of the damping valve device. With a conventional construction type, the vibration damper has a pipe socket via which the damping valve device is connected to the outer cylinder. 
     DE 34 18 262 A1 sets out, for example, in its FIG. 7, the problem of the radial structural space requirement. In order to mitigate the structural space requirement, a base is used for the outer cylinder, which already has a connection and channel geometry for the adjustable damping valve device. The outer cylinder is thereby extended. The disadvantage of this construction is an introduction of force into the connection region for the damping valve device. 
     FIG. 1 of DE 34 18 262 A1 shows that with smaller cylinder diameters a radial expansion is required in order to be able to use this special base. 
     SUMMARY OF THE INVENTION 
     An object of one aspect of the present invention is a vibration damper with an external damping valve device, which has a small structural spatial requirement in a radial direction with respect to the installation location of the vibration damper. 
     An object of one aspect of the present invention is a separate component is formed by an adapter sleeve that forms a portion of the working chamber and which has a connection piece with respect to the damping valve device. 
     With the use of a separate adapter sleeve, the configuration of the valve connection is independent of the diameter and the wall thickness of the inner cylinder. There is thereby produced a significantly larger construction play which can be used for a reduction of the radial expansion of the vibration damper. 
     In one aspect of the present invention, the inner cylinder is axially supported by the adapter sleeve inside the vibration damper. Consequently, no additional radial fixing of the adapter sleeve is required. The radial guiding is carried out via the axial connection portions of the adapter sleeve. 
     For example, the adapter sleeve may be supported on a base valve member. The base valve member is retained and centered in a manner known per se on the base of the outer cylinder so that this centering also acts on the adapter sleeve. 
     Alternatively, the adapter sleeve may also be supported on a piston rod guide which generally has a guiding attachment for the inner cylinder and then available for the adapter sleeve. 
     According to of one aspect of the present invention, an outer covering face of the adapter sleeve has a sliding guide for the connection piece. Theoretically, the adapter sleeve and the connection piece could be produced in one piece. With the sliding guide, however, position imprecisions of the components involved may be compensated for within the vibration damper. 
     With regard to a maximum reduction of the radial projection of the damping valve device, the adapter sleeve has a receiving member for a transfer connection piece of the damping valve device. In comparison with an intermediate pipe with a pipe socket as a carrier of a fluid connection between a working chamber and the damping valve device, the receiving member makes it possible for the connection piece of the adapter sleeve to be able to have dimensions which are extremely short. 
     In another advantageous embodiment, the spacing of a base of the receiving member from a longitudinal axis of the inner cylinder is smaller than an outer radius of the inner cylinder. The damping valve device can thereby be introduced radially more deeply into the vibration damper than a wall of the inner cylinder would allow. 
     In order to be independent of the orientation of the adapter sleeve inside the vibration damper during assembly, the receiving member is constructed as an annular groove. 
     To produce the flow connection between the working chamber and the damping valve device in a simple manner, the annular groove is connected to the working chamber by means of at least one connection opening. 
     Advantageously, the adapter sleeve comprises at least one separate connection ring which fixes the adapter sleeve to the working chamber. The adapter sleeve simplifies the axial connection of the adapter sleeve to the axially adjacent component. 
     To be able to reproduce a wider size range with a minimum number of connection rings, the adapter sleeve has at the end side a step-like connection profile. Each step represents a connection diameter from the construction kit of the connection components, for example, inner cylinder, piston rod guide or base valve member. 
     There may also be provision for the adapter sleeve to be configured in an axially divided manner. This construction type can be assembled in a particularly simple manner with the connection piece. 
     To keep the individual component costs low, two adapter sleeve portions are configured as identical components. No installation positions must be complied with since there is necessarily a symmetry for the dividing joint of the adapter sleeve. 
     To be better able to absorb any transverse forces, the two adapter sleeve portions are secured against rotation by at least one positive-locking connection. Another advantage is that, when the adapter sleeve portions have the radial connection openings and they are located in the axial dividing joint, they always move into abutment in an optimum manner with the end faces thereof. 
     Another advantageous feature is that at least one annular seal is arranged in an annular groove between a pipe piece and the adapter sleeve, wherein one groove side wall is formed by the adapter sleeve and one groove side wall is formed by the pipe piece. The adapter sleeve portions can then be produced without any cutting post-processing operation since there are no undercuts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is now intended to be explained in greater detail with reference to the following description of the Figures. 
       In the drawings: 
         FIG. 1  is a longitudinal section of the vibration damper; 
         FIG. 2  is a detailed illustration of the adapter sleeve according to  FIG. 1 ; 
         FIG. 3  is an axially divided adapter sleeve; 
         FIGS. 4 and 5  show a single-piece adapter sleeve; and 
         FIG. 6  shows an adapter sleeve in combination with a piston rod guide. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 
       FIG. 1  shows a vibration damper  1  with adjustable damping force in section, wherein details of a damping valve device  3 ,  5  have been omitted since the configuration of the damping valve device  3 ,  5  has no influence on the invention. For example, the vibration damper  1  has two separately adjustable damping valve devices  3 ,  5  which in this embodiment for a working movement are connected in each case to working chambers  7 ,  9  in an inner cylinder  11 . The inner cylinder  11  is subdivided by a piston  13  on an axially movable piston rod  15  into a piston-rod-side working chamber  7  and a working chamber  9  remote from the piston rod which are both completely filled with damping medium. At the end side, a base valve member  17  and a piston rod guide  19  close the two working chambers  7 ,  9 . 
     The damping medium displaced during a piston rod movement is received by an annular compensation space  21  between the inner cylinder  11  and an outer cylinder  23 . The compensation space  21  is filled via the discharge side of the two damping valve devices  3 ,  5 . A return flow from the compensation space  21  is carried out via the base valve member  17  into the working chamber  9  remote from the piston rod. 
     The two damping valve devices  3 ,  5  are arranged outside the outer cylinder  23  and connected via a welded pipe socket  25  to the outer cylinder  23 . 
     A first damping valve device  3  is subjected to flow via an intermediate pipe  27  which partially surrounds the inner cylinder  11  and which consequently forms a fluid connection  29  and which is connected to the piston-rod-side working chamber  7  via a fluid connection  31  in the wall of the inner cylinder  11 . Depending on the energization of a coil within the damping valve device  3 , the damping force is changed. With regard to structural details, reference may be made by way of example to DE 10 2013 209 928 A1. In this embodiment, it is assumed that both damping valve devices  3 ,  5  have only a single throughflow direction. 
     The second damping valve device  5  is connected via a flow connection  33  to the working chamber  9  remote from the piston rod. The flow connection  33  is formed by an adapter sleeve  35 , which is open at the end side with respect to the working chamber  9  remote from the piston rod and which consequently also constitutes a component of this working chamber. The adapter sleeve  35  constitutes a separate component from the inner cylinder  11  and has a connection piece  37  with respect to a transfer connection piece  39  of the damping valve device  5 . 
     The inner cylinder  11  is supported axially inside the vibration damper  1  via the adapter sleeve  35 . In this instance, a base  41  of the outer cylinder  23 , the base valve member  17 , the adapter sleeve  35 , the inner cylinder  11  and the piston rod guide  19  form a tension chain. In this embodiment, the adapter sleeve  35  is supported on the base valve member  17 . 
     The adapter sleeve  35  has on an outer covering face  43  a sliding guide  45  for the connection piece  37  (see  FIG. 2 ) which in turn is a constituent part of a pipe piece  47 . The connection piece  37  extends radially with respect to a longitudinal axis  49  of the inner cylinder  11 . 
       FIG. 2  shows a cut-out of the vibration damper according to  FIG. 1  with a first embodiment of the adapter sleeve  35 . 
     The adapter sleeve  35  comprises two separate connection rings  51 ,  53 , via which the adapter sleeve  35  is fixed, on the one hand, to the base valve member  17  and, on the other hand, to the inner cylinder  11  and consequently to the working chamber  9  remote from the piston rod. The connection rings  51 ,  53  as part of the adapter sleeve  35  have a step-like connection profile  55 ,  57  relative to the base valve member  17  and the inner cylinder  11  in order as a standard component to be able to receive different cylinder diameters or base valve members. It is possible to use, for example, a base valve member  17  which differs in diameter from the diameter of the inner cylinder  11 . 
     In this illustration, it can be seen that the adapter sleeve  35  has a receiving member  59  for the transfer connection piece  39  of the damping valve device  5 . The receiving member  59  itself is configured as an annular groove. The spacing of a base  61  of the receiving member  59 , that is to say, the annular groove base, with respect to the longitudinal axis  49  of the inner cylinder  11  is smaller than an outer radius of the inner cylinder  11 . This results in a very large radial structural space advantage in comparison with an arrangement as is present in  FIG. 1  in connection with the first damping valve device  3  and the intermediate pipe  27 . 
     Via the annular groove or the receiving member  59  and a number of connection openings  63 , the working chamber  9  remote from the piston rod is connected to the second damping valve device  5 . During an introduction movement of the piston rod  15 , the damper medium from the working chamber  9  remote from the piston rod is displaced via the adapter sleeve  35  through the connection openings  63  into the receiving member  59  and can flow further via the transfer connection piece  39  into the adjustable damping valve device  5 . 
     During assembly, the adapter sleeve  35  is provided with a sealing set  65  of annular seals, which seal the connection piece  37  in the sliding guide  45 . Subsequently, the pipe piece  47  is pushed with the connection piece  37  onto the adapter sleeve  35 . Subsequently, the end-side connection rings  51 ,  53  are pressed on. The base valve member  17  and the adapter sleeve  35  in turn form an easy press-fit with the connection ring  53 . The same applies to the connection between the inner cylinder  11  and the connection ring  51  so that this assembly unit is introduced into the outer cylinder  23  and fixed between the base  41  and the piston rod guide  19 . For the assembly of the damping valve device  5 , the connection piece  37  can be axially orientated via the pipe socket  25  which is still open in the outer cylinder  23  via a simple rod tool and in a precise manner in a peripheral direction so that there are no occurrences of torsion. As can be seen in the enlargement, the adapter sleeve  35  may have a substantially smaller outer radius than the inner cylinder  11  so that the radius difference is available as a structural space advantage. 
       FIG. 3  shows a cut-out from a vibration damper  1  according to the structural principle of  FIG. 1  with an axially divided adapter sleeve  35 . A dividing joint  67  is located precisely at a center of the annular receiving member  59  so that two adapter sleeve portions  35 A,  35 B are constructed as identical components. The function of the separate connection rings  51 ,  53  from  FIG. 2  is contained in the adapter sleeve portions  35 A,  35 B, that is to say, the outer covering face  43  in the region of the sliding guide  45  may have a significantly smaller radius than the outer radius of the inner cylinder  11 . 
     Both adapter sleeve portions  35 A,  35 B are secured relative to each other against rotation by a positive-locking connection  69 , schematically illustrated in this instance by an axial pin  71 , which engages in a blind hole opening  73 . A second positive-locking connection is located in a drawing plane rotated through 90°. The positive-locking connection  69  is intended to be understood to be only exemplary and other construction types may also be conceivable and advantageous. 
     The sealing set  65  according to  FIG. 2  is also used in this instance, there however being no two-sided annular groove in the adapter sleeve portions  35 A,  35 B, but instead annular grooves  75 ,  77 , in each case one groove side wall  79  is formed by the pipe piece  47  and one groove side wall  81  is formed by the adapter sleeve portions  35 A,  35 B. Via the sealing set  65  and the pretensions of the sealing set  65  by the pipe piece  47 , the adapter sleeve portions  35 A,  35 B are held together for the period of the preassembly. 
     During preassembly, the annular seals of the sealing set  65  are each pushed onto the adapter sleeve portions  35 A,  35 B. Afterwards, the adapter sleeve portions  35 A,  35 B are introduced into the pipe piece  47  so that there is then a manageable structural unit which can be assembled between the base valve member  17  and the inner cylinder  11 . 
       FIGS. 4 and 5  show a variant of the adapter sleeve  35  constructed in one piece and having a guiding attachment  83  for the inner cylinder  11  and a guiding web  85  for receiving the base valve member  17  at the end side. The diameter of the covering face  43  of the adapter sleeve  35  in  FIG. 4  substantially corresponds to the outer diameter of the inner cylinder  11 . The pipe piece  47  can thus be freely pushed over the inner cylinder  11  or over the base valve member  17  which is already mounted on the adapter sleeve  35 . 
     In  FIG. 5 , there is an adapter sleeve  35  in which the sliding guide  45  for the pipe piece  47  is smaller than the outer diameter of the inner cylinder  11 . To this end, the base valve member  17  has an outer diameter that corresponds to a maximum of the diameter of the sliding guide  45 . Consequently, the pipe piece  47  can be pushed over the side of the base valve member  17  onto the adapter sleeve  35 . 
     Even when the outer diameter of the covering face  43  is precisely as large as the outer diameter of the inner cylinder  11 , a notable advantage is still achieved since with this adapter sleeve solution the wall thickness of an intermediate pipe and the radial extent of the fluid connection would be omitted. 
     With  FIG. 6 , it is intended to be shown that the adapter sleeve  35  is not limited to use in the working chamber  9  remote from the piston rod.  FIG. 6  shows a cut-out of a vibration damper according to  FIG. 1 , in which the adapter sleeve  35  corresponds by way of example to the principle of  FIG. 3 . In this instance, the adapter sleeve  35  is also suitable for also cooperating with a stop  87 , which limits the travel path of the piston rod  15 . The embodiment according to  FIG. 6  can be combined both with an intermediate pipe known per se and fitted on the inner cylinder  11  or with a second adapter sleeve  35  in the working chamber  9  remote from the piston rod. 
     Furthermore, the adapter sleeve  35  contains according to  FIG. 6  the additional modification that the entire cross section of the annular groove  59  is configured as a portion of the flow connection  33  between the adapter sleeve  35  and the transfer connection piece  39  inside the adapter sleeve  35 . The pipe piece  42 , with the exception of the shoulders for receiving the sealing set  65 , can thereby have a constant inner diameter without any recesses. Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.