Abstract:
A pumping device may include a drive device coupled to a feed element via a hydrostatic coupling. The hydrostatic coupling may be configured to control a torque transmission between the drive device and the feed element. The hydrostatic coupling may include a suction side connected to a pressure side via a coupling-fluid-carrying channel. A valve device may be arranged in the coupling-fluid-carrying channel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application No. 10 2012 213 985.0, filed Aug. 7, 2012, and International Patent Application No. PCT/EP2013/066504, filed Aug. 6, 2013, both of which are hereby incorporated by reference in their entirety. 
       TECHNICAL FIELD 
       [0002]    The present invention relates to a pumping device with a drive device for driving a feed element of the pumping device according to the introductory clause of claim  1 . 
       BACKGROUND 
       [0003]    From EP 2 386 773 A2 a generic pumping device is known with a drive device for driving a feed element of the pumping device and with a gerotor coupling, by means of which a torque transmission between the drive device and the feed element is controllable. Through the coupling device which is uncoupled in such a manner, it is possible to not only transmit the full driving torque from the drive device to the feed element, but alternatively also any desired partial torques, this being without the wear phenomena occurring in conventional couplings, for example by a grinding of the coupling discs. 
         [0004]    From EP 1 736 669 A2 a further pumping device is known in the manner of a controllable coolant pump for internal combustion engines, by way of which the coolant temperature can be regulated continuously in a dependent precise and smooth manner. The coolant pump has here a pump shaft mounted in a pump bearing in the bearing housing, a seal sealing the bearing chamber from the pump chamber, and a freely rotatable pump wheel arranged on a sliding bearing of the pump shaft, which pump wheel is driven by a coupling, arranged on the pump shaft, as a function of the temperature of the coolant. In this case, the coupling is also constructed as a gerotor coupling. 
         [0005]    From DE 2 031 508 A1 a drive is known, operating according to the hydraulic principle, for example the gerotor principle. Here, a vacuum pump is driven by a hydraulic machine, by a fluid flow being directed through the hydraulic machine. 
       SUMMARY 
       [0006]    The present invention is concerned with the problem of indicating for a pumping device of the generic type an improved embodiment, which is distinguished in particular by an exact and structurally simple control, independent of the direction of rotation and independent of the rotation speed. 
         [0007]    This problem is solved according to the invention by the subject matter of the independent claim  1 . Advantageous embodiments are the subject matter of the dependent claims. 
         [0008]    The present invention is based on the general idea of providing a hydrostatic coupling, for example a gerotor coupling, in a pumping device known per se, for example an oil pump, a water pump, a vacuum pump or a fuel pump in a motor vehicle, between a drive device and a feed element of the pumping device, for example an impeller, by means of which hydrostatic coupling a torque transmission between the drive device and the feed element is able to be easily controlled or regulated. Coming into consideration as drive device is a further pump, the drive shaft of which is also used, a belt pulley, a toothed wheel, a chain wheel or a similar drive element. In order to enable here a control or regulation of the torque transmission in the hydrostatic coupling which is on the one hand structurally simple, but on the other hand is also exact, a suction side and a pressure side of the gerotor coupling are connected to one another by way of a coupling-fluid-carrying channel, wherein the coupling-fluid-carrying channel is itself flowed through by a coupling fluid, for example by oil, and wherein in the coupling-fluid-carrying channel a valve device is arranged. In fact, mention is usually made in the following to a gerotor coupling, wherein it is clear that of course this is to be understood to mean in general a hydrostatic coupling. Such a valve device can have, for example, an adjustable piston which according to position controls a through flow through the valve device and hence also a torque transmission of the gerotor coupling. Through the valve device according to the invention it is therefore possible to control a torque transmission in the gerotor coupling on the one hand in a structurally simple manner and on the other hand extremely exactly, so that not only an opening and closing of the gerotor coupling is possible, but also a transmission of merely partial torques. If therefore, for example, the drive device of the pumping device is switched on and transmits via a drive shaft a torque to an inner toothed wheel of the gerotor coupling, a torque transmission thus takes place in a pressure-dependent manner from the fluid situated in the gerotor coupling to the outer ring and therefore a torque transmission to the feed element of the pumping device. If the full torque is to be transmitted to the feed element, the valve device in the coupling-fluid-carrying channel is blocked, whereupon the pressure of the fluid conveyed by the gerotor coupling increases and thereby closes the coupling. Through the increasing pressure, the torque is now transmitted from the drive device via a corresponding shaft to an inner toothed wheel and from the latter to the outer ring. Ideally, the pressure side of the gerotor pump is completely sealed here, so that the drive torque can be transmitted completely to the feed element via the fluid enclosed in the chamber, for example oil. 
         [0009]    In an advantageous further development of the solution according to the invention, the coupling-fluid-carrying channel is connected with the channel duct of the main oil pump of the internal combustion engine and is therefore integrated into the oil circuit of the internal combustion engine. 
         [0010]    In an advantageous further development of the solution according to the invention, the valve devices and the gerotor coupling are able to be flowed through and used forwards and backwards. In this case, compared with couplings known from the prior art, the coupling is therefore able to be used in both rotation directions, so that the pumping device can run purely theoretically forwards or backwards and in both rotation directions a variable adjusting of a transmittable torque is possible at the gerotor coupling. 
         [0011]    Expediently, the valve device has an adjustable piston which, according to position, controls a through-flow through the valve device and therefore the torque transmission of the gerotor coupling. For adjusting the piston of the valve device, a setting device is provided here, which is configured in particular as a wax expansion element, a hydraulic setting device, a pneumatic setting device, an electrical setting device or a vacuum box. The multiplicity of the said possible embodiments of the possible setting devices already suggests how flexibly the hydrostatic coupling according to the invention is able to be used. 
         [0012]    In a further advantageous embodiment of the solution according to the invention, the gerotor coupling is integrated into a housing of the pumping device. Hereby, a particularly compact structural form can be achieved, which is of great advantage in particular in modern and cramped engine compartments. 
         [0013]    Expediently, the piston of the valve device is prestressed by means of a spring into a position closing the valve device. Such a spring is used to realize a so-called “fail-safe function”, so that on failure of the setting device the spring makes provision that the valve device closes and therefore likewise the gerotor coupling is also closed. With a closed gerotor coupling, a full torque transmission takes place from the drive device to the feed element and therefore a maximum possible conveying capacity of the pumping device, connected with the output side, which is of great advantage in particular in the construction as a coolant pump, because thereby an overheating of an internal combustion engine can be avoided. 
         [0014]    Further important features and advantages of the invention will emerge from the subclaims, from the drawings and from the associated figure description with the aid of the drawings. 
         [0015]    It shall be understood that the features mentioned above and to be explained further below are able to be used not only in the respectively indicated combination, but also in other combinations or in isolation, without departing from the scope of the present invention. 
         [0016]    Preferred example embodiments of the invention are illustrated in the drawings and are explained in further detail in the following description, wherein identical reference numbers refer to identical or similar or functionally identical components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    There are shown here, respectively diagrammatically, 
           [0018]      FIG. 1  an illustration of a possible embodiment of a gerotor coupling according to the invention, 
           [0019]      FIG. 2  a sectional illustration through a pumping device according to the invention, with gerotor coupling, 
           [0020]      FIG. 3  a pumping device according to the invention in the manner of an oil pump, 
           [0021]      FIG. 4  a sectional illustration along the section plane B-B of  FIG. 3 , 
           [0022]      FIG. 5  a sectional illustration through a pumping device constructed according to the invention as a water pump. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In accordance with  FIGS. 2 to 5 , a pumping device  1  according to the invention has a drive device  2  for the driving of a feed element  3 , for example of an impeller  4  (cf.  FIG. 5 ) of the pumping device  1 . In order to enable as fine a controlling or respectively regulating of the pumping device  1  as possible with regard to its conveying capacity, a hydrostatic coupling  5 , in particular a gerotor coupling  5 ′ (cf. also  FIG. 1 ) is provided, by means of which a torque transmission between the drive device  2  and the feed element  3  is able to be influenced. The pumping device  1  can be configured here for example as an oil pump (cf.  FIGS. 3 and 4 ) or as a water pump (cf.  FIG. 5 ) or else as a fuel pump. 
         [0024]    In the gerotor coupling  5  according to the invention, a suction side  6  and a pressure side  7  are connected with one another by way of a coupling-fluid-carrying channel  8 , wherein a valve device  9  is arranged in the coupling-fluid-carrying channel  8 . If one observes the valve device  9  more closely, it can be seen that the latter has an adjustable piston  10 , which according to position controls a through-flow through the valve device  9  and therefore a torque transmission of the coupling  5 , 5 ′. Also, a setting device  12  is provided for adjusting the piston  10  of the valve device  9 , which can be configured in particular as a wax expansion element, a hydraulic setting device, a pneumatic setting device, for example as an under box. The setting device  12  is operatively connected here with the piston  10 . A spring  11  is also provided, by means of which the piston  10  is prestressed into a position closing the valve device  9 , wherein with closed valve device  9 , during an operation of the pumping device  1  a build-up of pressure takes place in the coupling  5 , 5 ′, whereby a full torque transmission can be ensured from the drive device  2  to the feed element  3 . This is of great advantage in particular in a pumping device  1  configured as a coolant pump, because hereby an overheating for example of an internal combustion engine can be prevented. 
         [0025]    If one observes the gerotor coupling  5 ′ of  FIG. 1  more closely, it can be seen that it is able to be flowed through in both directions, i.e. both forwards and backwards, just as an associated valve device  9  which is to be adapted, so that generally the entire pumping device  1  can be operated both in a forwards operation and also in a backwards operation. 
         [0026]    According to  FIG. 1  the gerotor coupling  5 ′ has a drive shaft  13 , connected with the drive device  2  which is not shown, which drive shaft in this case brings about a torque transmission to an outer ring  14 . Furthermore, an inner ring  15  is provided, which has at least one tooth less than the outer ring  14  and together with the outer ring  14  encloses a displacement volume  16 . Here, either the inner ring  15  or the outer ring  14  can be mounted eccentrically. The inner ring  15  is connected by way of a torque-proof connection, for example a form-fitting or force-fitting connection, with the feed element  3 , for example by way of a shaft  17 . 
         [0027]    As can be further seen from  FIG. 1 , the inner ring  15  is mounted eccentrically to the outer ring  14 . Generally, of course, the inner ring  15  can also be connected in a torque-proof manner with the drive device  2 , wherein then the outer ring  14  is connected in a torque-proof manner with the feed element  3 . 
         [0028]    Observing  FIG. 2 , the coupling  5 , 5 ′ can be seen in a possible embodiment, wherein the reference numbers are largely taken over from  FIG. 1 . In order to obtain as full a torque transmission as possible with a closed valve device  9 , a gap seal  18  is provided, by means of which an undesired bypass flow and hence a loss of pressure in the displacement volume  16  can be prevented. At the same time, a sliding bearing  20  to a housing  19  takes place in this region. Observing  FIGS. 3 and 4 , the gerotor coupling  3  according to the invention can be seen in a pumping device  1  configured as an oil pump, wherein in particular in  FIG. 4  the sliding bearing  20  is again readily visible. 
         [0029]    In  FIG. 5  a pumping device  1 , configured as a water pump, is illustrated, with a feed element  3  configured as an impeller, with a seal  21 , which seals the water pump with respect to the coupling  5 , 5 ′, and with a housing  19 , into which the coupling  5 , 5 ′ is integrated. The coupling  5 , 5 ′ has again here an inner ring  15 , an outer ring  14  and a bearing  22  for bearing the drive shaft  13 . A cover plate  23  is additionally provided. 
         [0030]    The pumping device  1  can be controlled particularly exactly and in a problem-free manner with the coupling  5 , 5 ′ according to the invention. 
         [0031]    The principle which has been explained can also be transferred in an analogous manner to an internal gear pump, an external gear pump, a vane-type pump and a pendulum slide cell pump (PSC).