Abstract:
A pump unit of a vane-type pump having no dedicated housing including a drive shaft, a rotor that interacts with the drive shaft and accommodates vanes, a contour ring surrounding the rotor, and a first and a second side plate which are disposed laterally of the contour ring.

Description:
[0001]    The present invention relates to a pump unit of a vane-type pump having no dedicated housing. 
       BACKGROUND 
       [0002]    Pump units of the type discussed here are generally known. They are used, for example, in transmission housings of a motor vehicle or in other housings where a hydraulic supply is required. Pump units of this kind have a drive shaft, a rotor that cooperates with the drive shaft and that accommodates vanes which slide along a contour ring during a rotation of the rotor, two adjacent vanes enclosing cells which, in response to a rotation of the vanes, increase or decrease in volume, depending on the contour section, and, in the process, suction oil and discharge it again. In addition, a first and a second side plate are provided that are configured to the side of the contour ring. The known transmission pump units have the disadvantage that they tend to come apart during shipping, making it necessary to transport them in a housing or to undertake other measures for securing the same. Another disadvantage of the known pump units having no dedicated housing, is the relatively complex assembly that they require in a transmission housing, for example. 
       SUMMARY OF THE INVENTION 
       [0003]    It is, therefore, an object of the present invention is to provide a pump unit that will make it possible to avoid any destruction to the pump unit when transporting the same and, moreover, that will permit an especially simple installation of the pump unit in a housing. 
         [0004]    The present invention provides a pump unit having no dedicated housing, comprising a drive shaft; a rotor that cooperates with the drive shaft for accommodating vanes; a contour ring surrounding the rotor; a first and a second side plate, which are configured to the side of the contour ring. It is distinguished in that a sleeve is provided which is movably supported on the drive shaft and is located downstream of the second side plate in the axial direction of the pump unit. It also has the feature whereby a securing element is provided for axially securing the sleeve on the drive shaft, thereby preventing the pump unit from coming apart during shipment. Moreover, the pump unit features a spring element which preloads the second side plate against the transmission housing, the spring element being a fixed component of the pump unit. In this manner, the individual elements of the pump unit are held securely together even during transporting of the same and, moreover, it is ensured that the second side plate engages securely on the contour ring when the pump is assembled in a housing, thereby avoiding problems associated with starting up the pump unit. Another advantage of the pump unit provided here is the particularly flexible use thereof in that the spring element makes it possible to compensate for tolerances in the event of dimensional variations. 
         [0005]    One exemplary embodiment of the present invention is especially preferred that has the feature whereby the securing element is a locking ring that cooperates with the drive shaft. This provides for a reliable axial securing of the sleeve on the drive shaft, so that the individual components of the pump unit are not able to slip from the drive shaft during shipment. This eliminates the need for a pump housing for transporting the pump unit. It is thus possible to transport the pump unit as a compact unit without employing additional measures for securing the same. 
         [0006]    Another preferred exemplary embodiment of the present invention has the feature whereby the pump unit has a through drive. In this manner, a sampling of the rotational speed may be realized, for example, when two couplings are to be regulated. 
         [0007]    One exemplary embodiment of the present invention is also preferred which has the feature whereby the spring element is designed as a disk spring that is braced on one side against the second side plate and, on the other side, against the sleeve. The sleeve is then preferably supported, in turn, via a collar on the transmission housing, so that the spring element preloads the second side plate against the housing, in particular, against the transmission housing. This exemplary embodiment is particularly advantageous when the sleeve is movably supported in the axial direction on an extension of the second side plate. In this manner, when the pump is installed, a secure engagement of the pump components may be ensured. 
         [0008]    Another preferred exemplary embodiment of the present invention provides that this spring element, in particular the disk spring, is provided with orifices, so that flow-through channels, which have a lowest possible flow resistance, are formed which lead from the pressure outlets of the pump unit to a pressure chamber. 
         [0009]    Another preferred exemplary embodiment of the present invention provides that the sleeve and the second side plate are formed in one piece. In this exemplary embodiment as well, a securing element is preferably used to axially secure the sleeve. The spring element is designed as a compression spring, preferably as a coil spring, in particular as a frustoconical coil spring that is braced on one side against the second side plate and, on the other side, against a supporting device which is movably supported on the sleeve. The supporting device may be designed in any given manner, for example as a disk. It is also conceivable for a groove to be introduced into the sleeve and for one end of the coil spring to be displaceably positioned within the groove. In this specific embodiment, it is also important that the side plate be preloaded against the housing, so that, when the pump unit is assembled in a housing, a secure engagement of the individual components relative to one another is ensured, thereby avoiding the difficulties associated with starting up the pump unit. 
         [0010]    Another preferred exemplary embodiment of the present invention has the feature whereby a first axial bearing is realized by a shaft collar that cooperates with the rotor, and a second axial bearing is realized by a retaining ring that cooperates with the rotor. In this manner, the rotor itself is used as an axial bearing in the case of a pulling or a pushing of the drive shaft. 
         [0011]    One exemplary embodiment of the present invention is also preferred that has the feature whereby a shaft collar is provided for axially securing the first pressure plate. In this manner, all elements of the pump unit are securely supported on the drive shaft and are not able to fall off of the same. Thus, the pump unit may be safely transported without the need for any additional measures for securing the same. 
         [0012]    Finally, an exemplary embodiment of the present invention is preferred that has the feature whereby O-rings are provided for radially sealing the pump unit from the housing, the first side plate, the second side plate and the sleeve preferably cooperating with at least one O-ring. Radial shaft sealing rings are also provided, in particular for sealing pump components that execute a rotation relative to each other, a radial shaft sealing ring preferably being provided between the drive shaft and the first side plate, and a second radial shaft sealing ring between the drive shaft and the sleeve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The present invention is clarified in greater detail in the following, with reference to the drawing, whose figures show: 
           [0014]      FIG. 1  a schematized sectional view of a first exemplary embodiment of the pump unit; 
           [0015]      FIG. 2  a schematized sectional view of a second exemplary embodiment of the pump unit; and 
           [0016]      FIG. 3  an enlarged representation of a detail of the pump unit according to  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  shows a schematized sectional view of a pump unit  1  of a vane-type pump which is configured in a housing, here exemplarily in a transmission housing  3 . It encompasses a drive shaft  5 , which is connected in a torsionally fixed manner, for example via a toothing or the like, to a rotor  7 . Moreover, a contour ring  9  is provided that is configured around rotor  7  and is surrounded by a first side plate  11  and a second side plate  13  through which drive shaft  5  completely extends. The exact radial position of side plates  11  and  13 , as well as of contour ring  9  in relation to one another is ensured by pins  15  which extend completely through side plates  11  and  13  and contour ring  9 . 
         [0018]    Drive shaft  5  is driven by a driving gear, here purely exemplarily by a toothed wheel  17 . The use of a sprocket or of a belt drive or the like is also conceivable, however. 
         [0019]    Rotor  7  serves to accommodate a plurality of vanes  19 , which, in response to a rotation of rotor  7  about axis of rotation D of drive shaft  5 , slide along the inner side of contour ring  9 . Clearly discernible in  FIG. 1  is a suction region  21 , from where vane-type pump draws in hydraulic oil and delivers it via pressure outlets provided in second pressure plate  13  to a pressure chamber  25 . From there, the hydraulic oil reaches a consumer. The further operating principle of a vane-type pump is adequately described in the related art, so that there is no need to discuss it here in greater detail. 
         [0020]    Pump unit  1  has a sleeve  27  which is configured coaxially to drive shaft  5  and axially displaceably thereon. Moreover, it is situated downstream of second side plate  13  in the axial direction of pump unit  1 , thus in the direction of axis of rotation D, thus on the side of second side plate  13  opposing the drive side. To axially secure sleeve  27  on drive shaft  5 , a securing element  29  is provided, which is preferably designed as a locking ring and which prevents sleeve  27  from sliding off of drive shaft  5  during shipment of pump unit  1 . 
         [0021]      FIG. 1  makes it clear that sleeve  27 , having a first section  31  in transmission housing  3  and a second section  33 , is supported axially displaceably on an extension  35  of second side plate  13 . An O-ring seal  53  for radially sealing pump unit  1  is provided between extension  35  of second side plate  13  and second section  33  of sleeve  27 . 
         [0022]    In addition, pump unit  1  has a spring element  39 , which is configured coaxially to drive shaft  5  and which, on the one hand, in a radially outwardly disposed region with respect to axis of rotation D, is braced against second side plate  13  and, on the other hand, in a radially inwardly disposed region, is braced against sleeve  27 . In this case, spring element  39  is designed as a disk spring and is provided with orifices  41  to ensure a fluid communication between pressure outlets  23  and pressure chamber  25 . Orifices  41  are preferably formed in a way that provides a lowest possible flow resistance of spring element  39 . Conceivable, however, is the design of spring element  39  as a frustoconical coil spring. Important in this case is the design of spring element  39  as a compression spring which is able to preload second side plate  13  against the housing. 
         [0023]    At its end facing away from toothed wheel  17 , shaft  5  has a through drive  43 , which is provided here purely exemplarily with an inductor  45 , in order to realize a rotational speed sampling. To this end, inductor  45  preferably encompasses permanent magnets which cooperate with a sensor for recording the rotational speed of drive shaft  5 . 
         [0024]    In the exemplary embodiment in accordance with  FIG. 1 , pump unit  1  is axially secured in transmission housing  3  purely exemplarily by a housing component  48 . However, a locking washer or the like may conceivably be used to secure pump unit  1  in transmission housing  3  in a different manner, for example. 
         [0025]    To radially seal pump unit  1  from transmission housing  3 , a first radial shaft sealing ring  47  configured between first side plate  11  and drive shaft  5 , and a second radial shaft sealing ring  49  configured between sleeve  27  and drive shaft  5  are provided. Since it is a question of components that execute a relative movement during operation of pump unit  1 , the use of O-rings would be inadequate in this case. Moreover, an O-ring seal  51  is provided to provide radial sealing between first side plate  11  and transmission housing  3 . An O-ring seal  52  also seals second side plate  13  from transmission housing  3  in the radial direction. 
         [0026]    Another O-ring seal  53  is provided in the area between second section  33  of sleeve  27  and extension  35  of second side plate  13 . Finally, for radial sealing action, an O-ring seal  55  is also configured between a section  57  of sleeve  27 , which has a reduced diameter compared to remaining sleeve  27 , and transmission housing  3 . 
         [0027]    To axially secure first side plate  11 , drive shaft  5  is provided with a shaft collar  59 , so that first side plate  11  is prevented from falling off of drive shaft  5 . 
         [0028]    Overall, therefore, it has been shown that pump unit  1  is designed as a compact unit, all of whose elements are securely supported, on the one hand, by shaft collar  59  and, on the other hand, by securing ring  29  on drive shaft  5 , and that pump unit  1  is reliably prevented from coming apart during shipment. 
         [0029]    During shipment of pump unit  1 , respectively in the uninstalled state of pump unit  1 , spring element  39  is in the more relieved state, so that sleeve  27  is axially displaced on drive shaft  5  and on extension  35  and is pressed against securing ring  29 . 
         [0030]    When transmission unit  1  is installed in transmission housing  3 , section  57  of sleeve  27  that is reduced in diameter is introduced into an opening  59  provided in transmission housing  3 , until sleeve  27  engages on a collar  61  on transmission housing  3 . Pump unit  1  may then be displaced further into transmission housing  3  until its optimal position is reached. In this installed state of pump unit  1 , spring element  39  is compressed, so that second side plate  13  is preloaded against sleeve  27  and thus against transmission housing  3 , and is pressed against contour ring  9 , which, in turn, is braced against first side plate  11 , which, for its part, is axially secured by housing part  48 . Thus, already in the unpressurized state of pump unit  1 , the spring force of spring element  39  ensures a secure engagement and sealing of the two side plates on contour ring  9 , and thus a pressure build-up and a frictionless start-up of pump unit  1 . Thus, the pump components are held securely together even during the transporting of pump unit  1 . 
         [0031]      FIG. 1  clearly shows that, in the installed state of pump unit  1 , sleeve  27  no longer engages on securing ring  29 ; rather, due to the engagement of collar  61  on transmission housing  3 , it is configured at a distance of a few millimeters therefrom. Thus, in the uninstalled state of pump unit  1 , a certain amount of play is present between the individual pump elements, so that spring element  39  does not exert its full action until pump unit  1  is installed. Moreover, a particular advantage of pump unit  1  provided here is that spring element  39  constitutes a fixed component of pump unit  1 . Moreover, it is particularly advantageous that spring element  39  compensates for any existing manufacturing tolerances that may arise in the case of the bore provided in transmission housing  3  for accommodating pump unit  1 . 
         [0032]    The embodiment of pump unit  1  provided here is particularly advantageous when a through drive  43  is provided, for example, to realize a rotational speed sampling. 
         [0033]    The present pump unit  1  also encompasses two axial bearings for the case that the shaft is pushed in the direction of arrow  63  or drive shaft  5  is pulled in the direction of arrow  65 . Operating states of this kind should, in fact, be avoided during operation of pump unit  1 . However, it is necessary to provide axial bearings for the case that an operating state of this kind occurs. 
         [0034]    For this purpose, in the case of pump unit  1  for realizing a first axial bearing, a collar  67  is provided on drive shaft  5  that is configured to the left next to rotor  7 , and that, in response to a displacement of drive shaft  5  in the direction of arrow  63 , is urged into engagement with rotor  7  and entrains the same, so that rotor  7  is displaced in the direction of second side plate  13 . To realize a second axial bearing, a securing ring  69  that is configured to the right next to rotor  7  is provided on drive shaft  5 , and, in response to a movement of drive shaft  5  in the direction of arrow  65 , entrains rotor  7  and displaces the same in the direction of first side plate  11 . It is evident that rotor  7  is used here as an axial bearing, which, in response to an axial loading of the shaft, cooperates with first side plate  11 , respectively with second side plate  13 . 
         [0035]      FIG. 2  shows a schematized sectional view of a second exemplary embodiment of a pump unit  1 . Like parts are denoted by the same reference numerals, so that, in this respect, reference is made to the description of  FIG. 1 . 
         [0036]    In contrast to  FIG. 1 , merely one section of pump unit  1  is shown in  FIG. 2 . In the exemplary embodiment in accordance with  FIG. 2 , a sleeve  27 ′ is formed in one piece with second side plate  13 . A frustoconical coil spring that is configured coaxially to drive shaft  5  is used as spring element  39 ′ and is braced at one end against side plate  13  in a radially outwardly disposed region with respect to axis of rotation D and is braced by its other end in a radially inwardly disposed region against a supporting device  71 . 
         [0037]    For the sake of illustration,  FIG. 3  shows an enlarged representation of the corresponding region of pump unit  1 . It is clear that supporting device  71  is movably supported on sleeve  27 ′. It must be designed in such a way that it is not able to fall off of sleeve  27 ′. To this end, it may cooperate, for example, with a suitable securing element  72  that is introduced into sleeve  27 ′ and that is designed here exemplarily as a retaining ring. 
         [0038]    As illustrated in  FIG. 2 , supporting device  71  may, for example, be designed as a disk that is used as an abutment for spring element  39 ′. 
         [0039]    To axially secure sleeve  27 ′ on drive shaft  5 , a retaining ring corresponding to the exemplary embodiment in accordance with  FIG. 1  may be provided which prevents sleeve  27 ′ from falling out. However, a retaining ring  73  may also be provided, which is configured between drive shaft  5  and sleeve  27 ′ and permits an axial displacement of sleeve  27 ′ via an elongated, annular-groove shaped region. 
         [0040]    In this exemplary embodiment as well, an O-ring seal  55  seals sleeve  27 ′ from transmission housing  3  in the radial direction. To ensure a sealing action between sleeve  27 ′ and drive shaft  5 , the first exemplary embodiment provides a radial shaft sealing ring  49  in accordance with  FIG. 1 . 
         [0041]    It is evident that, even in the case of the second exemplary embodiment, a compact pump  1  is devised whereby the danger of a breakup during shipment is avoided by a securing element, in particular, by retaining ring  73 . Moreover, here as well, spring element  39  fulfills the advantageous function of preloading second side plate  13  against transmission housing  3 , so that a secure engagement of the individual pump elements against one another is provided, and a start-up of the pump in the unpressurized state is ensured, and, at the same time, manufacturing tolerances are compensated. 
         [0042]    In the installed state of pump unit  1  in accordance with  FIG. 2 , sleeve  27 ′ is again configured in opening  59  of transmission housing  3 . However, in contrast to the exemplary embodiment in accordance with  FIG. 1 , sleeve  27 ′ is not supported via a collar on transmission housing  3 ; rather, spring element  39 ′ is braced against supporting device  71  and thus directly against transmission housing  3 . In this manner, spring element  39 ′ exerts a force on second side plate  13 , so that side plates  11  and  13  rest against contour ring  9 . In this context, a shifting of side plate  13  and, consequently, a shifting of sleeve  27 ′ in opening  59  may occur, which is why supporting device  71 ′ must be movably supported on sleeve  27 ′. Depending on how far sleeve  27 ′ projects into opening  59 , spring element  39 ′ is compressed to a greater or lesser degree. In the disassembled state of pump unit  1 , thus, in particular, during shipment, spring element  39 ′ shifts supporting device  71  as far to the right as possible, up to a limit stop on sleeve  27 ′, so that spring element  39 ′ is again in a more relieved state. 
         [0043]    Due to the movable positioning of supporting element  71  on sleeve  27 ′, it is always pressed by spring element  39 ′ against transmission housing  3 . 
         [0044]    Altogether, it has been shown that a pump unit is devised by the present invention that has the feature whereby a sleeve  27 , respectively  27 ′ is provided, which is movably supported on the drive shaft and is situated downstream of second side plate  13  in the axial direction of pump unit  1 , and that a securing element  29 , respectively  73  is provided for axially securing sleeve  27 ,  27 ′ on drive shaft  5 . In this manner, pump unit  1  may be transported without the need for any additional measures for securing the same, since a falling apart of pump unit  1  is avoided. Spring element  39 , respectively  39 ′ is a fixed component of pump unit  1  and preloads second side plate  13  against transmission housing  3 . In this manner, a separation of the pump elements is avoided in the unpressurized state of pump unit  1 , and the sealing action allows pump unit  1  to readily build up pressure and start up. Moreover, manufacturing-induced tolerances are compensated by spring element  39 ,  39 ′, thereby permitting an optimal adaptation of pump unit  1  and allowing for an especially flexible use thereof. 
       LIST OF REFERENCE NUMERALS 
       [0045]      1  pump unit 
         [0046]      3  transmission housing 
         [0047]      5  drive shaft 
         [0048]      7  rotor 
         [0049]      9  contour ring 
         [0050]      11  first side plate 
         [0051]      13  second side plate 
         [0052]      15  pins 
         [0053]      17  toothed wheel 
         [0054]      19  vane 
         [0055]      21  suction region 
         [0056]      23  pressure outlet 
         [0057]      25  pressurized chamber 
         [0058]      27  sleeve 
         [0059]      27 ′ sleeve 
         [0060]      29  retaining ring 
         [0061]      31  first section 
         [0062]      33  second section 
         [0063]      35  extension 
         [0064]      39  spring element 
         [0065]      39 ′ spring element 
         [0066]      41  orifices 
         [0067]      43  through drive 
         [0068]      45  inductor 
         [0069]      47  first radial shaft sealing ring 
         [0070]      48  housing component 
         [0071]      49  second radial shaft sealing ring 
         [0072]      51  O-ring seal 
         [0073]      53  O-ring seal 
         [0074]      55  O-ring seal 
         [0075]      57  section 
         [0076]      59  opening 
         [0077]      61  collar 
         [0078]      63  arrow (pulling) 
         [0079]      65  arrow (pushing) 
         [0080]      67  collar 
         [0081]      69  retaining ring 
         [0082]      71  supporting device 
         [0083]      72  retaining ring 
         [0084]      73  retaining ring