Abstract:
In order to improve a compensation reservoir for a hydraulic operating system, in particular for a hydraulic brake system or a clutch system, comprising a housing in the interior of which a storage chamber which is provided for storing hydraulic medium is bounded by a separating element which changes its shape in accordance with a volume of the storage chamber, it is proposed that the housing engages over the separating element in all of its shapes, which correspond to possible volumes of the storage chamber, in a protective manner, that a filling level-indicating region of the separating element changes its position in the housing when the volume which is taken up by the hydraulic medium which is stored in the storage chamber changes, and this position in each case represents a filling level-indicating position, and that the filling level-indicating position which is situated within the housing is visible from outside the housing through a viewing region of the housing.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This patent application claims the benefit of German application No. 10 2015 110 723.6, filed Jul. 2, 2015, the teachings and disclosure of which are hereby incorporated in their entirety by reference thereto. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a compensation reservoir for a hydraulic operating system, in particular a hydraulic brake system or a clutch system, comprising a housing in the interior of which a storage chamber which is provided for storing hydraulic medium is bounded by a separating element which changes its shape in accordance with a volume of the storage chamber. 
         [0003]    Compensation reservoirs of this kind are known from the prior art. 
         [0004]    However, the problem of being able to identify the magnitude of the volume of the storage chamber in as simple a manner as possible is encountered in the case of said compensation reservoirs. 
         [0005]    In the case of a compensation reservoir of the kind described in the introductory part, this object is achieved, according to the invention, in that the housing engages over the separating element in all of its shapes, which correspond to possible volumes of the storage chamber, in a protective manner, in that a filling level-indicating region of the separating element changes its position in the housing when the volume which is taken up by the hydraulic medium which is stored in the storage chamber changes, and this position in each case represents a filling level-indicating position, and in that the filling level-indicating position which is situated within the housing is visible from outside the housing through a viewing region of the housing. 
       SUMMARY OF THE INVENTION 
       [0006]    The advantage of the solution according to the invention is that the magnitude of the volume of the storage chamber can be detected solely by detecting the filling level-indicating position of the filling level-indicating region of the separating element, and that the separating element is also protected by the housing against external damage by virtue of the solution according to the invention. 
         [0007]    This provides a simple way of detecting the volume of the storage chamber, specifically simply by detecting the filling level-indicating region of the separating element, and secondly nevertheless protects the separating element itself in an optimum manner by virtue of the housing. 
         [0008]    A particularly expedient solution provides that the filling level-indicating position of the filling level-indicating region of the separating element is represented by the shape of the filling level-indicating region. 
         [0009]    By way of example, the shape of the filling level-indicating region of the separating element can be detected by the degree of curvature of the separating element in the interior of the housing. 
         [0010]    In this case, it is particularly expedient when the filling level-indicating position of the filling level-indicating region of the separating element is represented by a relative position in relation to a marking or boundary of the viewing region, so that a person who detects the filling level-indicating position can detect the relative position of the filling level-indicating position in a simple manner in relation to this marking or boundary of the viewing region. 
         [0011]    However, it is also feasible to subdivide the viewing region into a plurality of subregions and, for example, to detect that subregion of the viewing region in which the filling level-indicating position is visible, wherein a specific volume of the storage chamber is associated with the respective subregion. 
         [0012]    However, as an alternative to this, it is also feasible to provide a scale in the viewing region and to assign different magnitudes of volume to individual scale elements, so that the magnitude of the volume of the storage chamber can be detected by comparing the filling level-indicating position with the scale. 
         [0013]    Up until now, no detailed information has been provided in respect of the arrangement of the separating element within the housing. 
         [0014]    By way of example, the separating element itself could be in the form of a bladder within the interior and the size of the bladder could represent the filling level-indicating position of the said bladder. 
         [0015]    However, a particularly expedient solution provides that the separating element is connected to a base element of the housing. 
         [0016]    In this case, it is preferably provided that the storage chamber is surrounded by the separating element and the base element. 
         [0017]    That is to say that, in this case, the separating element changes its shape in accordance with the magnitude of the volume of the storage chamber, starting from the base element. 
         [0018]    By way of example, an advantageous solution in this respect proposes that a region of the base element is of tub-like design and the tub interior forms a subchamber of the storage chamber, wherein, in particular, this subchamber is supplemented with a further subchamber which is bordered by the separating element adjoining the tub interior, so that the two subchambers together produce the storage chamber. 
         [0019]    In order to be able to integrate the base element into the housing in a particularly simple manner, it is preferably provided that a wall attachment of the base element, which wall attachment runs around a housing axis in a closed manner, forms a base region of a side wall of the housing. 
         [0020]    Up until now, no detailed information has been provided in respect of the arrangement of the viewing region of the housing. 
         [0021]    It is therefore preferably provided that the viewing region of the housing is arranged such that an expansion chamber for the separating element, which expansion chamber is provided in the housing, is visible. 
         [0022]    As a result, it is possible to detect all of the filling level-indicating positions of the separating element which are situated within the expansion chamber. 
         [0023]    In this case, the expansion chamber is preferably arranged such that at least all of the filling level-indicating positions of the separating element which correspond to a volume of the storage chamber which is larger than the minimum volume lie within the expansion chamber, so that the said positions can be detected through the viewing region. 
         [0024]    In this case, the viewing region of the housing can be a continuous region which is designed such that at least the filling level-indicating positions of all of the volumes of the storage chamber which correspond to a volume which is greater than the minimum volume can be detected. 
         [0025]    However, it is also feasible to subdivide the viewing region into partial viewing regions through which different regions of the expansion chamber are visible. 
         [0026]    In the simplest case, the viewing region can be a strip-like region. 
         [0027]    A particularly simple solution provides that the viewing region of the housing surrounds the expansion chamber, so that the expansion chamber is visible on all sides. 
         [0028]    In the embodiments in which the separating element is connected to the base element of the housing, it is preferably provided that the viewing region of the housing runs away from the base element in one direction of extent, so that all of the filling level-indicating positions of the separating element which correspond to a volume which is greater than the minimum volume can be detected and indicate the magnitude of the volume by virtue of their distance from the base element. 
         [0029]    In a particularly preferred embodiment, it is provided that the viewing region comprises a UV filter, so that the separating element is advantageously protected against a damaging effect due to UV light. 
         [0030]    In particular, the viewing region is substantially impermeable to UV light, that is to say that in particular at most 10%, preferably at most 5%, particularly preferably at most 1% of the UV light which strikes the viewing region is transmitted through the said viewing region, for example into the expansion chamber. 
         [0031]    By way of example, the viewing region is substantially impermeable to electromagnetic radiation with a wavelength of less than 380 nm, in particular less than 360 nm, and/or to electromagnetic radiation with a wavelength of greater than 200 nm, in particular greater than 250 nm, for example greater than 280 nm, that is to say that at most 10%, preferably at most 5%, in particular at most 1%, of the electromagnetic radiation of this kind which is incident on the viewing region is transmitted through the viewing region, in particular into the expansion region. 
         [0032]    In particular, the viewing region is composed of a material which absorbs UV light. 
         [0033]    Up until now, no detailed information has been provided in respect of the configuration of the housing. 
         [0034]    A solution which can be realized in a structurally particularly simple manner therefore provides that the expansion chamber is surrounded by a side wall element of the housing. 
         [0035]    In order to form the viewing region, it is expediently provided in this case that the side wall element is partially transparent. 
         [0036]    As an alternative to this, it is provided that the side wall element is completely transparent. 
         [0037]    In a particularly preferred embodiment, it is provided that the side wall element comprises at least one transparent insert which, at least partially, forms the viewing region. 
         [0038]    In particular, the at least one transparent insert is transparent to visible light. 
         [0039]    Therefore, the at least one transparent insert is preferably substantially permeable to electromagnetic radiation with a wavelength of greater than 380 nm, in particular greater than 400 nm, and/or to electromagnetic radiation with a wavelength of less than 800 nm, in particular less than 780 nm, for example less than 750 nm, wherein the at least one transparent insert is substantially permeable to electromagnetic radiation of this kind when, in particular, at least 90%, preferably at least 95%, in particular at least 99%, of the electromagnetic radiation of this kind which is incident on the at least one transparent insert is transmitted through the said insert. 
         [0040]    It is particularly preferred when the at least one transparent insert is substantially impermeable to UV light, wherein the at least one transparent insert is substantially impermeable to UV light when at most 10%, in particular at most 5%, preferably at most 1%, of the UV light which is incident on the at least one transparent insert, that is to say, for example, incident electromagnetic radiation with a wavelength of less than 380 nm, in particular less than 360 nm, and/or incident electromagnetic radiation with a wavelength of greater than 200 nm, in particular greater than 250 nm, for example greater than 280 nm, is transmitted through the at least one transparent insert. 
         [0041]    A further alternative solution provides, for example, that the side wall element has apertures through which the equalizing chamber is visible. 
         [0042]    No further information in respect of the design of the separating element itself has been provided in connection with the prior explanation of the individual embodiments. 
         [0043]    A particularly expedient solution therefore provides that the separating element comprises a diaphragm body which is in the form of a dimensionally variable diaphragm or in the form of a bellows. 
         [0044]    Furthermore, it is preferably provided that the separating element comprises a sealing body which seals off the storage chamber at the transition between the separating element and the housing. 
         [0045]    In this case, the sealing body can be provided in addition to the diaphragm body, for example as two bodies which are arranged adjacent to one another in particular. 
         [0046]    A particularly advantageous solution provides that the sealing body and the diaphragm body are integrally formed. 
         [0047]    Furthermore, the sealing body can be in the form of, for example, an O-ring seal which is entirely deformed for sealing-off purposes. 
         [0048]    It is particularly advantageous when a bead region of the sealing body is arranged on the diaphragm body by way of a connecting section of the sealing body. 
         [0049]    In this case, the bead region of the sealing body is, in particular, of voluminous design, so that the said bead region provides a large amount of sealing material and is readily compressible and therefore the transition between the separating element and the housing is sealed off in a particularly expedient manner. 
         [0050]    In particular, the bead region is thicker than the connecting section, for example the bead region is thicker than the connecting section in respect of a cross section which runs from the interior of the housing to outside the housing. 
         [0051]    A particularly expedient solution provides that the sealing body comprises at least one sealing lip for forming a sealing line since, owing to the design of a sealing line, improved sealing off itself is possible due to a lower amount of pressure being applied. 
         [0052]    It is particularly expedient when the sealing body comprises a plurality of sealing lips for forming a sealing line in each case. 
         [0053]    By way of example, the housing has a receptacle for the separating element, preferably for the sealing body of the separating element, in particular for the bead region of the sealing body. 
         [0054]    It is particularly expedient when the side wall element has the receptacle for the separating element, preferably for the sealing body of the separating element. 
         [0055]    In particular when sealing off between the separating element and the base element, it is preferably provided that the base element has a receptacle for the sealing body of the separating element. 
         [0056]    In this case, the receptacle can be designed in an extremely varied way. 
         [0057]    By way of example, the base element can have a step-like receptacle. 
         [0058]    A solution which is particularly expedient in respect of sealing off which is as optimal as possible provides that the receptacle is designed in the form of a channel. 
         [0059]    In this case, the channel can have any desired cross section, for example a semicircular or a rectangular cross section. 
         [0060]    In this case, it is particularly advantageous when the at least one sealing lip or the plurality of sealing lips bear against wall regions of the channel for the purpose of forming sealing lines. 
         [0061]    In a particularly advantageous embodiment, it is provided that the sealing body is acted on by at least one pressure element, as a result of which particularly effective sealing off is achieved in an advantageous manner. 
         [0062]    In particular, it is provided that the sealing body is acted on by at least two pressure elements, as a result of which redundant sealing off is provided. 
         [0063]    By way of example, the sealing body is acted on by two pressure elements. 
         [0064]    It is particularly expedient when the bead region of the sealing body is acted on by at least one pressure element since the said bead region provides a large amount of sealing material for pressing and sealing, and therefore particularly expedient sealing off is achieved. 
         [0065]    By way of example, the connecting section of the sealing body is acted on by at least one pressure element. 
         [0066]    In order to achieve particularly optimal sealing off, it is preferably provided that the sealing body in the receptacle is acted on by a pressure element and is deformed in relation to the state in which it is not acted on in order to thereby improve sealing off in the receptacle. 
         [0067]    Up until now, no further information has been provided in respect of the design of the pressure element. 
         [0068]    By way of example, it is feasible to provide the pressure element as a separate element. 
         [0069]    A solution which is structurally particularly simple and also expedient for assembly provides that the pressure element is held against the side wall element. 
         [0070]    By way of example, the pressure element is in the form of a projection of the side wall element or in the form of an extension of the side wall element in this case. 
         [0071]    In particular, it is expedient in this case when the pressure element and the side wall element are integrally formed. 
         [0072]    Particularly when the sealing body comprises at least one sealing lip or a plurality of sealing lips, it is preferably provided that the at least one sealing lip bears against the receptacle in a sealing manner by virtue of the sealing body being acted on. 
         [0073]    It is even more advantageous when the plurality of sealing lips bear against the receptacle in a sealing manner by virtue of the sealing body being acted on. 
         [0074]    In a particularly advantageous embodiment, it is provided that the compensation reservoir is integrated into the brake fitting of a vehicle, in particular into the brake fitting of a steering device-controlled vehicle. 
         [0075]    The invention further relates to a brake fitting of a vehicle, in particular the brake fitting of a steering device-controlled vehicle. 
         [0076]    In particular, the brake fitting is provided for a quad bike and/or a two-wheeled vehicle, for example a pedelec, a bicycle or a motorcycle. 
         [0077]    A portion of a hydraulic operating system is integrated into a fitting housing of the brake fitting, wherein the hydraulic operating system comprises a master cylinder, a brake cylinder and a compensation reservoir. 
         [0078]    By way of example, the brake fitting comprises a loading device for the master cylinder. 
         [0079]    In particular, it is provided that the fitting housing at least partially forms a housing of the master cylinder. 
         [0080]    In this case, the compensation reservoir which is integrated into the brake fitting comprises one or more of the abovementioned features. 
         [0081]    It is particularly preferred when the fitting housing forms a portion of a housing of the compensation reservoir. 
         [0082]    By way of example, the fitting housing forms a base element of the compensation reservoir. 
         [0083]    Further features and advantages of the solution according to the invention are the subject matter of the following description and the drawing showing a number of exemplary embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0084]      FIG. 1  shows a schematic illustration of a hydraulic operating system; 
           [0085]      FIG. 2  shows a section through a first exemplary embodiment of a compensation reservoir according to the invention; 
           [0086]      FIG. 3  shows an illustration, in the form of an enlarged detail, of the compensation reservoir according to  FIG. 2  in a region of a receptacle of a base element; 
           [0087]      FIG. 4  shows an illustration of a brake fitting comprising a compensation reservoir according to a second exemplary embodiment of the solution according to the invention; 
           [0088]      FIG. 5  shows a section V-V according to  FIG. 4  through the brake fitting according to the second exemplary embodiment; 
           [0089]      FIG. 6  shows a section VI-VI according to  FIG. 4  through the compensation reservoir according to the second exemplary embodiment; 
           [0090]      FIG. 7  shows an illustration, in the form of an enlarged detail, according to  FIG. 4  in the region of the compensation reservoir; 
           [0091]      FIG. 8  shows an illustration, in the form of an enlarged detail, of a section according to  FIG. 6  in a region of a side wall element of the compensation reservoir according to the second exemplary embodiment, and 
           [0092]      FIG. 9  shows an illustration, in the form of a detail, of a base element and a separating element in a region of an inlet duct. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0093]    A hydraulic operating system which is schematically illustrated in  FIG. 1  and is designated  10  overall, for example for a vehicle, for example a quad bike or a two-wheeled vehicle, in particular a pedelec, a bicycle or else a motorcycle, comprises a master cylinder  12  which is integrated, for example, in a brake fitting for a vehicle, for example a quad bike or a two-wheeled vehicle, in particular a pedelec, a bicycle or else a motorcycle, and an operating cylinder  14 , wherein the master cylinder  12  supplies pressurized hydraulic medium to the operating cylinder  14  by means of a first hydraulic line  16 , and also comprises a compensation reservoir  30  which is connected, for example, to the brake fitting or is integrated into the brake fitting and which is provided for storing and for providing hydraulic medium, in such a way that, as required, hydraulic medium from the hydraulic medium reservoir which is located in the compensation reservoir  30  enters the master cylinder  12  through second hydraulic line  34 , which is connected to the compensation reservoir  30  and equalizes a deficiency in hydraulic medium in said master cylinder, and in this way the hydraulic operating system  10  and, in particular, the master cylinder  12  are always supplied with a sufficient amount of hydraulic medium. 
         [0094]    One exemplary embodiment of a compensation reservoir  30  according to the invention comprises a dimensionally stable housing which is designated  40  overall and is connected, for example, to the master cylinder  12  and is, for example, at least partially integrated into the brake fitting of the vehicle, for example of the quad bike or the two-wheeled vehicle, wherein a storage chamber  46  which is provided for storing hydraulic medium is arranged in an interior  44  of the housing  40 , the volume of the said housing being defined without fluctuating by the boundary provided by the dimensionally stable housing  40  ( FIG. 2 ). 
         [0095]    The volume of the storage chamber  46  corresponds substantially to the volume of the hydraulic medium which is stored in the said storage chamber and is therefore subject to fluctuations which result, for example, from the inflow or outflow of hydraulic medium. 
         [0096]    In the interior  44  of the housing  40 , the storage chamber  46  is bounded by an at least partially dimensionally variable separating element  52 , which is in the form of an elastic diaphragm or in the form of a bellows in particular, so that fluctuations in the volume of the storage chamber  46  cause a change in the shape of the separating element  52 , and wherein the separating element  52  can expand, starting from a minimum volume of the storage chamber  46 , to a maximum volume in the event of an increase in volume of the said storage chamber into an expansion chamber  48  which is provided in the interior  44  for this purpose, but the entire volume of the interior  44  which is bounded by the housing  40  remains unchanged in the process. 
         [0097]    Owing to the arrangement of the separating element  52  in the interior  44  of the housing  40 , the separating element  52  is protected by the housing  40  against external effects in an optimum manner. 
         [0098]    The housing  40  extends along a housing axis  54  in the direction of a direction  56  of extent from a base element  64 , which is arranged in a first housing end region  62  and which is arranged, for example, on the brake fitting of the vehicle, for example of the quad bike or of the two-wheeled vehicle, or in particular is integrated into the said brake fitting, to a cover element  68  which is arranged in a second housing end region  66 , wherein an at least partially optically transparent side wall  74  is arranged in a housing intermediate region  72  which is situated between the first housing end region  62  and the second housing end region  66 . 
         [0099]    The base element  64  comprises an outlet, which is designated  82  overall, by means of which the storage chamber  46  is connected to the second hydraulic line  34 , so that, as required, hydraulic medium passes from the storage chamber  46 , via the outlet  82 , into the second hydraulic line  34  and further enters the master cylinder  12 . 
         [0100]    In this embodiment, the outlet  82  comprises an outlet duct  84  which, in a first outlet end region  86 , issues into the storage chamber  46  by means of an outlet opening  88  and, starting from the first outlet end region  86 , opens into the second hydraulic line  34 . 
         [0101]    The base element  64  bounds the storage chamber  46  in a first boundary region  96 , wherein the first boundary region  96  is surrounded by a first boundary contour  98  and, for example, the first boundary region  96  forms a, in particular substantially planar, boundary base area  102  of the base element  64  for the storage chamber  46 . 
         [0102]    In this exemplary embodiment, the base element  64  has a wall attachment  108  which rises in the direction  56  of extent, in particular starting from the area which is spanned by the boundary base area  102 , wherein, in particular, the wall attachment  108  is arranged in a base region  112  of the side wall  74 . 
         [0103]    The wall attachment  108  of the base element  64  is designed so as to run around the housing axis  54  in a closed manner. 
         [0104]    In particular, the wall attachment  108  runs along the first boundary contour  98  and rises as far as a second boundary contour  118 , so that the wall attachment  108  surrounds the storage chamber  46  along a second boundary region  122  which is situated between the first boundary contour  98  and the second boundary contour  118 . 
         [0105]    The base element  64  is preferably of tub-like design in one region, wherein the first boundary region  96  forms the tub base and the second boundary region  122  forms the tub wall, and the tub interior  128  which is enclosed by the tub which is formed in this way forms a subchamber of the storage chamber  46 . 
         [0106]    In this exemplary embodiment, a side wall element  132  between the base element  64  and the cover element  68  forms a side wall intermediate region  134  of the side wall  74 . 
         [0107]    In particular, the side wall element  132  adjoins the base element  64  in a flush manner at the second boundary contour  118  and adjoins the cover element  68  in a flush manner at a third boundary contour  136 . 
         [0108]    By way of example, an integral design of the side wall element  132  and the cover element  68  is also possible. 
         [0109]    The cover element  68  closes off the housing  40  in the second housing end region  66 . 
         [0110]    By way of example, the cover element  68  substantially has the geometric shape of the boundary base area  102  of the base element  64 . 
         [0111]    The cover element  68  is situated either in a flat geometric area, in particular which is free of raised portions, or in a curved geometric area, in particular which is free of raised portions. 
         [0112]    It is also feasible for a region of the cover element  68  to form a region of the side wall  74 . 
         [0113]    A projection  146  is advantageously arranged on the cover element  68  in a region of the third boundary contour  136 , in particular along the third boundary contour  136 , so as to run around the housing axis  54  in a closed manner, so that the projection  146  forms a stop for the side wall element  132 , which stop prevents a relative change in position transverse to the housing axis  54  between the cover element  68  and the side wall element  132 . 
         [0114]    A fastening element  152 , which is in the form of a tie rod or in the form of a screw for example, connects the base element  64 , the side wall element  132  and the cover element  68  in such a way that the positions of these elements relative to one another are fixed. 
         [0115]    If the cover element  68  and the side wall element  132  are optionally of integral design and therefore connected to one another, it is also possible for the fastening element  152  to connect the base element  64  only to the cover element  68  or the side wall element  132 , so that the positions of these elements are likewise fixed relative to one another in this way. 
         [0116]    In this embodiment, the housing  40  is formed in such a way that geometric cross-sectional regions, which are produced by the geometric sectioning of the housing  40  with geometric cross-sectional areas which are situated one above the other in the direction  56  of extent, wherein the cross-sectional areas  154  and  154 ′ which are illustrated by way of example in  FIG. 2  are perpendicular to the plane of the illustration, have a substantially identical geometric, for example substantially rectangular, ellipsoidal or circular, shape, wherein shapes which are substantially identical are intended to be understood to mean, in particular, shapes which can be mapped onto one another by stretching. 
         [0117]    As already mentioned, the separating element  52  is arranged on the housing  40  in such a way that the separating element  52  separates the storage chamber  46  from the expansion chamber  48  in the interior  44  of the housing  40 , in particular in a media-tight manner, so that, in particular, no hydraulic medium can escape from the storage chamber  46  into the expansion chamber  48  and, for example, no air can enter the storage chamber  46  from the expansion chamber  48 . 
         [0118]    By way of example, the separating element  52  arches in the shape of a bell over the base element  64 , in particular over the tub interior  128 , and the storage chamber  46  extends from the base element  64  as far as the separating element  52 , so that the base element  64  and the separating element  52  surround the storage chamber  46  in a closed manner. 
         [0119]    The separating element  52  is preferably held between the base element  64  and the side wall element  132  and forms a media-tight, in particular air-tight and hydraulic medium-tight, termination  176  for the storage chamber  46  with the base element  64 . 
         [0120]    In this exemplary embodiment, the base element  64 , in particular the wall attachment  108 , comprises a receptacle  178  which runs around the housing axis  54  in a closed manner and is arranged, for example, either along the first boundary contour  98  or along the second boundary contour  118 , for a sealing body of the separating element  52 , which sealing body is designated  182  overall, the interaction between the said sealing body and the said receptacle  178  allowing the media-tight termination  176  to be formed ( FIG. 2 , in the form of an enlarged detail in  FIG. 3 ). 
         [0121]    By way of example, the receptacle  178  is situated in a receptacle plane  184  which runs perpendicular to the housing axis  54 . 
         [0122]    The receptacle  178  which is arranged, in particular, between an inner side wall section  186  and an outer side wall section  188  is designed in the form of a channel, which is designated  190  overall, which has a channel opening  192  which is averted from the base element  64  and, in particular, faces the cover element  68  or the side wall element  132 , and, starting from the said channel opening, an inner channel wall  194  and an outer channel wall  196  and also a channel base  198 . 
         [0123]    The sealing body  182 , which is of annular design and borders the circumference of an at least partially dimensionally variable, in particular an entirely dimensionally variable, diaphragm body  202  of the separating element  52  and, in particular, is integrally formed on the diaphragm body  202 , is situated in the channel  190 . 
         [0124]    The channel  190  receives the sealing body  182 , which is designed so as to correspond to the channel  190  in respect of its shape, so as to terminate with it in a sealing manner. 
         [0125]    The sealing body  182  of the dimensionally variable separating element  52  comprises a plurality of sealing lips  206 ,  208 ,  212  which are braced by an inner body  204 . 
         [0126]    In particular, two of the sealing lips  206 ,  208 ,  212  are designed such that they bear against the channel base  198  and/or against the inner channel wall  194  or against the outer channel wall  196  or, in particular, in an edge which is formed by the inner channel wall  194  or the outer channel wall  196  with the channel base  198 , and a further of the sealing lips  206 ,  208 ,  212  rests against the outer channel wall  196  at a distance from the channel base  198 , so that preferably a total of three sealing lines are formed between the sealing body  182  and the base element  64 , the said sealing lines forming a reliable media-tight termination  176 . 
         [0127]    A pressure element  216 , for example a shoulder  224  which is arranged on that side  222  of the side wall element  132  which faces the interior  44 , acts on the sealing body  182  in an engaging manner, in particular through the channel opening  192 , and, when the housing  40  is closed by means of the fastening element  152 , for example a screw-connection of the housing  40  by means of the fastening element  152  which is in the form of a screw, presses the sealing body  182  into the channel  190 , so that the plurality of sealing lips  206 ,  208 ,  212  spread and form sealing lines, which terminate in a sealing manner, along the channel base  198  or the inner channel wall  194  or the outer channel wall  196 . 
         [0128]    The diaphragm body  202  which is connected to the sealing body  182  in a manner extending through a gap  228  between the pressure element  216  and the channel  190 , for example produced by the shoulder  224  engaging only partially over the channel  190  in the radial direction in relation to the direction  56  of extent, extends from the sealing body  182  over the storage chamber  46  and engages over, in particular, the first boundary region  96  of the base element  64  and possibly the second boundary region  122  of the base element  64 . 
         [0129]    In a filling level-indicating region  232  of the separating element  52 , in particular of the diaphragm body  202 , the separating element  52  is of flexible design, so that in the event of a change in volume of the hydraulic medium which is stored in the storage chamber  46 , the said change in volume being caused by hydraulic medium flowing out through the outlet  82  for example, the filling level-indicating region  232  changes a filling level-indicating position  234  which indicates the respective filling level of stored hydraulic medium in the storage chamber  46 . 
         [0130]    By way of example, the degree of curvature in the direction away from the base element  64  or in the direction of the base element  64  of the filling level-indicating region  232  gives the filling level of the hydraulic medium which is stored in the storage chamber  46 , so that the degree of curvature of the filling level-indicating region  232  represents the filling level-indicating position  234 . 
         [0131]    By way of example, it is also feasible for the position of the filling level-indicating region  232  to represent the filling level-indicating position  234  relative to a scale, in particular the distance from the filling level-indicating region  232  to the receptacle plane  184 . 
         [0132]    In particular, a minimum filling level-indicating position of the filling level-indicating region  232  which the filling level-indicating position  234  moves to when the filling level of stored hydraulic medium in the storage chamber  46  reaches a predefined minimum filling level can be provided. 
         [0133]    By way of example, the filling level-indicating region  232  signals, when it extends into the receptacle plane  184  and no longer arches over said receptacle plane or is no longer at a distance from the receptacle plane  184 , that the filling level of the stored hydraulic medium in the storage chamber  46  has reached the minimum filling level. 
         [0134]    By way of example, it is also feasible for the filling level-indicating region  232  to move to a maximum filling level-indicating position when the filling level of the stored hydraulic medium in the storage chamber  46  reaches a predefined maximum filling level. By way of example, the filling level-indicating region  232  signals, when it comes into contact with the side wall element  132  or the cover element  68 , that the filling level of the stored hydraulic medium in the storage chamber  46  has reached the maximum filling level. 
         [0135]    The filling level-indicating position  234  of the filling level-indicating region  232  is visible from outside the housing  40  through a transparent viewing region  242 , which is arranged on the housing  40  in particular. 
         [0136]    Various embodiments of the transparent viewing region  242  are possible. 
         [0137]    By way of example, one element of the housing  40 , in particular the side wall element  132  and/or the cover element  68  or else the base element  64 , comprises a subregion which forms the transparent viewing region  242  and is of transparent design. 
         [0138]    In this embodiment, the respective element of the housing  40 , for example the side wall element  132  and/or the cover element  68  or else the base element  64 , is formed entirely from a transparent material. 
         [0139]    In this embodiment of the compensation reservoir  30 , the viewing region  242  is formed by the side wall element  132  which, in particular, rises in the direction  56  of extent over the base element  64  and surrounds the expansion chamber  48 . 
         [0140]    Therefore, the viewing region  242  is situated in the housing intermediate region  72 . 
         [0141]    In particular, the transparent viewing region  242  extends away from the receptacle  178  in the direction of the direction  56  of extent, in particular away from the receptacle plane  184 , starting from the base element  64 . 
         [0142]    The viewing region  242  preferably runs along the second boundary contour  118  and therefore entirely around the housing axis  54 , so that the filling level-indicating region  232  of the separating element  52  can be identified from all sides. 
         [0143]    By way of example, it is also feasible for the viewing region  242  to be arranged in an element of the housing  40 , for example the side wall element  132  or else the cover element  68 , and to be formed by one or more apertures in the respective element of the housing  40 , wherein, in particular, a plurality of apertures which are at a distance from one another and are situated one above the other in the direction of the direction  56  of extent form a scale for reading off the filling level of the hydraulic medium which is stored in the storage chamber  46  by identifying the filling level-indicating position  234  through one of the apertures. 
         [0144]    By way of example, one aperture indicates the minimum filling level in that, as long as a sufficient amount of hydraulic medium is stored in the storage chamber  46 , at least one region of the separating element  52  is at a further distance from the base element  64 , in particular from the receptacle plane  184 , than the aperture, so that the filling level-indicating region  232  is visible through the aperture but, if the filling level of the hydraulic medium which is stored in the storage chamber  46  drops below the minimum filling level, the separating element  52 , in particular the filling level-indicating region  232 , is at a shorter distance from the base element  64 , in particular from the receptacle plane  184 , than the aperture, and therefore the filling level-indicating region  232  is no longer visible through the aperture and therefore the minimum filling level is indicated. 
         [0145]    In summary, selected elements of the compensation reservoir  30  function as follows: 
         [0146]    If hydraulic medium flows out of the storage chamber  46 , via the outlet  82 , into the second hydraulic line  34  in order to replace hydraulic medium in the hydraulic operating system  10 , the volume of the hydraulic medium which is stored in the storage chamber  46  and consequently the shape and/or the relative position in relation to a marking of the flexible filling level-indicating region  232  of the separating element  52 , in particular the degree of curvature of the filling level-indicating region  232 , are reduced, so that the filling level-indicating position  234  of the filling level-indicating region  232  is changed. 
         [0147]    Since the filling level-indicating position  234  of the filling level-indicating region  232  is visible through the viewing region  242  from outside the housing  40 , the configuration according to the invention of the compensation reservoir  30  therefore firstly allows the filling level of the hydraulic medium which is stored in the storage chamber  46  to be read off by a user of the hydraulic operating system  10  from outside the housing  40 , wherein secondly the storage chamber  46  is closed off in a media-tight manner in a simple fashion and the separating element  52  is protected by the housing  40  against external effects. 
         [0148]    If the filling level of the hydraulic medium which is stored in the storage chamber  46  is reduced as far as the minimum filling level, the filling level-indicating position  234  of the filling level-indicating region  232  moves to the minimum-filling level-indicating position, for example formed by a specific degree of curvature of the filling level-indicating region  232 , in particular by said region extending into the receptacle plane  184 , or formed by reaching the filling level-indicating region  232  of a marking in the viewing region  242 , for example the transition from the transparent base element  64  to the transparent side wall  74 , and the user of the hydraulic operating system  10  is able to identify by virtue of this minimum-filling level-indicating position that the storage chamber  46  needs to be refilled with hydraulic medium. 
         [0149]    In the case of a second exemplary embodiment of a solution according to the invention, those parts which are identical to those of the first exemplary embodiment are provided with the same reference symbols, so that reference can be made in full to the statements made in relation to the first exemplary embodiment for description of the said second exemplary embodiment. 
         [0150]    In the case of the second exemplary embodiment, a portion of a hydraulic operating system  10 ′ is integrated into a fitting housing  301  of a brake fitting  302  ( FIGS. 4 and 5 ). 
         [0151]    The brake fitting  302  is provided for a vehicle, in particular for a steering device-controlled vehicle. 
         [0152]    For the purpose of being arranged on the vehicle, the brake fitting  302  comprises a fastening apparatus  303 , for example a portion of a screw connection. 
         [0153]    A master cylinder  12 ′ and a compensation reservoir  30 ′ of the hydraulic operating system  10 ′ are arranged in the fitting housing  301 ; in particular, the fitting housing  301  forms a housing of the master cylinder  12 ′ and a housing  40 ′ of the compensation reservoir  30 ′ at least in regions. 
         [0154]    A first hydraulic line  16 , which connects the master cylinder  12 ′ to an operating cylinder  14  of the hydraulic operating system  10 ′ so as to carry fluid, can be connected to the brake fitting  302 . 
         [0155]    The brake fitting  302  further has a loading device  304  which, in this exemplary embodiment, comprises a brake lever which is arranged on the fitting housing  301 . 
         [0156]    The loading device  304  is connected to the master cylinder  12 ′ so as to transmit force and, in the event of operation of the loading device  304 , a loading element  306  of the loading device  304  acts on a piston  308  of the master cylinder  12 ′. 
         [0157]    When the loading element  306  acts on the piston  308 , the piston  308  is set into motion and acts on hydraulic medium which is provided in the hydraulic operating system  10 ′. 
         [0158]    A second hydraulic line  34 ′, which connects the master cylinder  12 ′ and the compensation reservoir  30 ′ in a fluid-carrying manner, is arranged in the brake fitting  302 , in particular integrated into the fitting housing  301 , in the manner of a duct. 
         [0159]    The fitting housing  301  forms a base element  64 ′ of the compensation reservoir  30 ′. 
         [0160]    A wall attachment  108  of the base element  64 ′ partially surrounds the interior  44 , in particular the storage chamber  46  of the compensation reservoir  30 ′. 
         [0161]    A cover element  68 ′ of the compensation reservoir  30 ′ firstly extends in the second housing end region  66  and, starting from this second housing end region, the cover element  68 ′ secondly extends in the direction of the base element  64 ′ and in the process partially surrounds the expansion chamber  48  ( FIGS. 5 and 6 ). 
         [0162]    Therefore, the cover element  68 ′ likewise forms a side wall element  132 ′. 
         [0163]    The cover element  68 ′ and the side wall element  132 ′ bound the expansion chamber  48  in the direction axial to the main axis  54  in the second housing end region  66  and border the expansion chamber  48  in the direction radial to the housing axis  54 . 
         [0164]    The side wall element  132 ′ comprises a transparent insert  312  which forms a transparent viewing region  242 ′. 
         [0165]    In this exemplary embodiment, a first transparent insert  3121  and a second transparent insert  31211  are provided, wherein, for example, the transparent inserts  3121  and  31211  are arranged on opposite sides of the side wall element  132 ′. 
         [0166]    The transparent inserts  3121  and  31211  are of identical design, and therefore the said inserts are described jointly in the text which follows and explicit mention of the specifications I and II is dispensed with in the description of the said inserts. 
         [0167]    The transparent insert  312  is permeable to visible light, so that the expansion chamber  48  is visible through the transparent insert  312 . 
         [0168]    A separating element  52 ′ and also the filling level-indicating region  232  of the said separating element are also visible through the transparent insert  312 . 
         [0169]    The transparent insert  312  is formed from a UV light-absorbing material and is therefore substantially impermeable to UV light. 
         [0170]    Therefore, the viewing region  242 ′ comprises a UV filter. 
         [0171]    By way of example, the transparent insert  312  is in the form of a separate portion of the side wall element  132 ′. 
         [0172]    In this case, the transparent insert  312  can be inserted into a cutout  313  in the side wall element  132 ′. 
         [0173]    The cutout  313  is bordered by a border  314  of the side wall element  132 ′. 
         [0174]    The transparent insert  312  is arranged so as to bear against the border  314  ( FIGS. 6, 7 and 8 ). 
         [0175]    In the direction of the direction  56  of extent of the compensation reservoir  30 ′, the transparent insert  312  extends from a first end section  315  as far as a second end section  316  and, transverse to this, from a first side region  317  as far as a second side region  318 . 
         [0176]    In the side regions  317  and  318 , the border  314  engages around the transparent insert  312  by way of holding elements  321  and  322 , wherein the holding elements  321  and  322  hold the transparent insert  312  in the cutout  313 . 
         [0177]    In the side regions  317  and  318 , the transparent insert  312  is arranged, at least in sections, between the interior  44  of the compensating container  30 ′ and the border  314 , and the border  314  in this way forms a stop for the transparent insert  312  in sections so that the transparent insert  312  does not slide away from the interior  44 . 
         [0178]    The transparent insert  312  lies on the side wall element  132 ′ by way of the first end section  315 . 
         [0179]    The transparent insert  312  engages over a base section  324  of the border  314  by way of a lug  323 , wherein the base section  324  is arranged between the interior  44  and the lug  323 . 
         [0180]    By way of example, the border  314  is formed as a step which rises in the direction of the direction  56  of extent in the region of the first end section  315 , the raised portion of the said step facing the interior  44  and the lug  323  engaging over the raised portion of the step on a side which is averted from the interior  44 . 
         [0181]    The transparent insert  312  bears against the cover element  68 ′ by way of the second end section  316 . 
         [0182]    The transparent insert  312  engages beneath the border  314  by way of a latching section  326 , so that, in the direction of the direction  56  of extent, the transparent insert  312  is arranged, in particular clamped, between a region of the border  314 , which region is arranged on the cover element  68 ′, on the one hand and a region of the border  314 , which region is arranged on the side wall element  132 ′, on the other hand. 
         [0183]    The side wall element  132 ′ bears against a support section  336  of the base element  64 ′ by way of an end section  332  in a contact region  334 . 
         [0184]    The side wall element  132 ′ comprises a receptacle, which is designated  342  overall, for a sealing body  182 ′ of the separating element  52 ′. 
         [0185]    The receptacle  342  is in the form of a channel  190 ′ with a channel opening  192 ′ which faces the base element  64 ′. 
         [0186]    Starting from the channel opening  192 ′, an outer channel wall  196 ′ and an inner channel wall  194 ′ extend in a direction away from the base element  64 ′ as far as a channel base  198 ′ which connects the channel walls  194 ′ and  196 ′ and closes off the channel  190 ′. 
         [0187]    Therefore, in this exemplary embodiment, the channel base  198 ′ is arranged above the channel opening  192 ′ in relation to the direction  56  of extent. 
         [0188]    The inner channel wall  194 ′ is arranged on a side of the channel  190 ′ which faces the interior  44  of the compensation reservoir  30 ′, and the outer channel wall  196 ′ is arranged on a side which is situated opposite that side which faces the interior  44 . 
         [0189]    The outer channel wall  196 ′ extends, starting from the channel  190 ′, through the channel opening  192 ′ as far as the end section  332  of the side wall element  132 ′. 
         [0190]    The inner channel wall  194 ′ forms a side of a projection  346  of the side wall element  132 ′, which side is averted from the interior  44 . 
         [0191]    The projection  346  extends to a lesser extent in the direction of the base element  64 ′ than the side wall element  132 ′ by way of its end section  332  in the direction of the base element  64 ′, so that a gap  228 ′ is arranged between the projection  346  and the base element  64 ′, in particular between the projection  346  and the bearing section  336  of the base element  64 ′. 
         [0192]    The gap  228 ′ is formed in the manner of a clearance between the projection  346  and the base element  64 ′. 
         [0193]    The separating element  52 ′ engages through the gap  228 ′ and the sealing body  182 ′ of the separating element  52 ′ is arranged at least partially in the receptacle  342 . 
         [0194]    In addition, the sealing body  182 ′ rests on the support section  336  of the base element  64 ′. 
         [0195]    The sealing body  182 ′ is situated in the channel  190 ′ by way of a bead region  352 . 
         [0196]    In this case, the bead region  352  of the sealing body  182 ′ extends through the channel opening  192 ′ from the side wall element  132 ′ as far as the base element  64 ′, in particular from the channel base  198 ′ as far as the support section  336  of the base element  64 ′. 
         [0197]    The bead region  352  is connected to the diaphragm body  202  of the separating element  52 ′ by way of a connecting section  354  of the sealing body  182 ′. 
         [0198]    In this case, the connecting section  354  extends through the gap  228 ′. 
         [0199]    The bead region  352  of the sealing body  182 ′ is thicker than the connecting section  354 . 
         [0200]    In this case, the thickness of the sealing body  182 ′, that is to say of the bead region  352  and of the connecting section  354 , is measured transverse to a direction of extent of the sealing body  182 ′ from the bead region  352  in the direction of the connecting section  354  as far as the diaphragm body  202 . 
         [0201]    That is to say, the thickness of the sealing body  182 ′ and also of the bead region  352  and of the connecting section  354  relates to a cross section of the sealing body  182 ′, wherein the cross section runs from the interior  44  of the compensation reservoir  30 ′ to outside the compensation reservoir  30 ′. 
         [0202]    In addition, the bead region  352  extends from a side which faces the base element  64 ′ as far as a side which faces the side wall element  132 ′ further than the connecting section  354  extends from a side which faces the base element  64 ′ as far as a side which faces the side wall element  132 ′. 
         [0203]    In this case, both the bead region  352  and the connecting section  354  rest on the support section  336  of the base element  64 ′ by way of their side which faces the base element  64 ′. 
         [0204]    In this exemplary embodiment, it is provided that a support surface  356  of the support section  336  for the sealing body  182 ′ is substantially planar. 
         [0205]    However, in one variant, it is provided that the support section  336  comprises, for example, a step or a receptacle for the sealing body  182 ′. 
         [0206]    The side wall element  132 ′ engages over, in particular, the bead region  352  of the sealing body  182 ′, wherein the projection  346  of the side wall element  132 ′ is arranged between the bead region  352  and the interior  44 . 
         [0207]    The side wall element  132 ′ acts on the sealing body  182 ′ and therefore the sealing body  182 ′ is pressed between the side wall element  132 ′ and the base element  64 ′ and therefore forms the media-tight termination  176 . 
         [0208]    In this case, a large surface area of the sealing body  182 ′ rests on the support section  336  of the base element  64 ′, so that particularly expedient sealing off is performed. 
         [0209]    The side wall element  132 ′ acts on the sealing body  182 ′, in particular the connecting section  354 , by way of the projection  346 , so that the projection  346  is also in the form of a pressure element  2161 ′. 
         [0210]    In addition, the side wall element  132 ′ acts on the sealing body  182 ′, in particular the bead region  352 , even in the receptacle  342 . 
         [0211]    In this case, the channel base  198 ′ in particular presses on the bead region  352  of the sealing body  182 ′, wherein the bead region  352  provides a large amount of sealing material for compression, so that particularly expedient sealing-off is achieved. 
         [0212]    Therefore, a portion of the side wall element  132 ′ is in the form of a further pressure element  21611 ′ in the region of the channel base  198 ′. 
         [0213]    Therefore, in the second exemplary embodiment, redundant sealing off is provided by the side wall element  132 ′. 
         [0214]    The compensation reservoir  30 ′ comprises an inlet apparatus  362  by means of which new hydraulic medium can be introduced into the storage chamber  46  and in this way the storage chamber  46  can be refilled with hydraulic medium. 
         [0215]    The housing  40 ′, in particular the cover element  68 ′, comprises an inlet opening  364  which can be closed in a media-tight manner by way of a closure  366 , and, if required, the closure  366  can be separated from the inlet opening  346  again and in this way the inlet opening  364  can be reopened. 
         [0216]    The inlet opening  364  issues into an inlet duct  368  of the housing  40 ′ which connects the inlet opening  364  to the storage chamber  46 . 
         [0217]    In this exemplary embodiment, the inlet duct  368  is arranged in the base element  64 ′. 
         [0218]    In an inlet region  372 , the inlet opening  364  issues into the inlet duct  368  which extends from the inlet region  372  as far as a mouth region  374  and issues into the storage chamber  46  in the mouth region  374 . 
         [0219]    In this exemplary embodiment, the inlet duct  368  is in the form of a recess in the base element  64 ′, which recess passes from the inlet region  372  as far as the mouth region  374 . 
         [0220]    A seal  376  is provided in the inlet region  372  between the inlet opening  364 , which is arranged on the cover element  68 ′ for example, and the inlet duct  368 , which is arranged in the base element  64 ′ for example, for sealing-off purposes. 
         [0221]    In this exemplary embodiment, the seal  376  is integrally formed with the separating element  52 ′. 
         [0222]    In particular, a sealing-off section  378  of the separating element  52 ′ extends from the mouth region  374  as far as the inlet region  372  over the inlet duct  368 , which is in the form of a recess for example, and seals off the said inlet duct between the mouth region  374  and the inlet region  372 . 
         [0223]    Otherwise, all further parts in the second exemplary embodiment are identical to those of the first exemplary embodiment, and therefore reference can be made to the statements made in relation to the first exemplary embodiment.