Abstract:
A plug-in shaft system comprising a hollow stub shaft inside of which a shaft is put to transmit torque, a sealing cap being fastened to a front end of the hollow stub shaft to seal the interior of the hollow stub shaft from the passage of oil, and an oil guiding cap being fastened to the front of the hollow stub shaft at an axial distance to the oil sealing cap, the oil guiding cap defining an oil guiding space. A differential, such as a straight differential, including the plugin shaft system, wherein preferably two sun gears are used.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is the United States National Stage Application pursuant to 35 U.S.C. §371 of International Application No. PCT/EP2013/059818, filed on May 13, 2013, which application claims priority from German Patent Application No. DE 10 2012 214 771.3, filed on Aug. 20, 2012, which applications are incorporated herein by reference in their entireties. 
     DESCRIPTION 
     1. Field of the Invention 
     The invention relates generally to an insert shaft system, having a hollow shaft stub, wherein a shaft is inserted into the interior thereof in a torque transmitting manner, wherein a seal cap is attached on an end face of the hollow shaft stub, sealing the interior of the hollow shaft stub in a manner preventing the flow of oil through the same. 
     2. Background of the Invention 
     A differential arrangement having lubrication feed lines is known from the prior art, for example, U.S. Pat. No. 5,989,143 (Bell et al.). A hollow shaft having oil channels is known from European Patent No. EP 0362043 A1 (Hubert et al.). Lubrication devices for transmissions are also known from European Patent No. EP 1 031 766 B1 (Udou) and German Patent No. DE 600 01 123 T2 (Udou et al.). Transmissions and oil feed mechanisms for a power transmission device are known from German Patent Application Publication No. DE 10 2006 000 080 A1 (Usami et al.) and German Patent Application Publication No. DE 10 2009 055 005 A1 (Takeuchi et al.). 
     The known systems, however, have disadvantages pertaining to the exploitation of the constructed space, the ease of assembly, the cost-efficiency thereof, and the seal which they achieve. 
     BRIEF SUMMARY OF THE INVENTION 
     According to aspects illustrated herein, there is provided an insert shaft system including a hollow shaft stub having an interior and an end face, a shaft inserted into the interior of the hollow shaft stub in a torque transmitting manner, a seal cap attached on the end face of the hollow shaft stub, the seal cap operatively arranged to seal the interior of the hollow shaft stub to prevent a flow of oil through the same and an oil distributor cap attached at an axial distance from the seal cap on the end face of the hollow shaft stub, the oil distributor cap and the seal cap forming an oil distribution chamber. 
     According to aspects illustrated herein, there is provided an insert shaft system of the class, in that an oil distributor cap is attached, at an axial distance from the seal cap, on the end face of the hollow shaft stub, forming an oil distribution chamber. In an example embodiment, the oil distributor cap is fixed in the hollow shaft stub, or is attached in a manner surrounding the hollow shaft stub. In this way, it is possible on the one hand to realize a very compact construction, and on the other to provide a unit which is particularly simple to install. 
     In order to achieve a particularly good lubrication, it is advantageous if at least one oil channel flows into the oil distribution chamber, or if a plurality of oil channels flows into the same, the oil channels preferably being parallel to each other. 
     It is also advantageous if the oil distributor cap has a funnel-like depression which is preferably arranged in the center thereof. In this manner, oil can easily be fed to a further hollow shaft, particularly if the funnel-like depression flows into a tube which is inserted into the other hollow shaft. 
     The conveyance of fluid is also facilitated if the depression flows into an oil outlet opening. 
     It is further advantageous if the oil distribution chamber is designed as a gap, and particularly an annular gap, which is preferably produced by spacer elements which are pushed through axially in the direction of the end face of the hollow shaft stub. 
     A configuration in which the oil distributor cap is made of a metallic material such as steel has been demonstrated particularly durable and particularly able to accept loads. 
     It is also advantageous if the hollow shaft stub and the shaft—the same preferably designed as a solid shaft—are connected to each other via a toothing, in a positive- and/or force-fitting manner. In this way, it is possible to easily implement a transmission of torque, and also to simplify the assembly thereof. 
     The possible applications are increased in number if the hollow shaft stub is part of a sun gear, by the shaft being configured in the manner of a sun gear shaft. 
     The invention also relates to a differential, such as a spur gear differential, having an insert shaft system, wherein two sun gears are preferably used in the same. 
     It is also advantageous if there is a depression in the oil distributor cap at the end face of the oil channel, the depression oriented in this direction, or the oil distributor cap has at least three projections which are evenly distributed on the inside thereof, such that there is a space between the end of the oil channel and the oil distributor cap. This space can then be used to achieve a particularly efficient oil distribution. This configuration prevents a blunt face placement of the oil distributor cap, and an associated sealing of the oil channels. 
     It is further advantageous if there is at least one eccentric oil channel in the hollow shaft stub, running at least sectionally in the axial direction. 
     It is also advantageous if two or more oil channels are arranged on both sides of an axis of rotation. It is possible to simplify the manufacturing process and to improve the lubricating behavior of the insert shaft system in this way. 
     It is also advantageous if the oil channel has an oil outlet opening on the end face of the hollow shaft stub. The discharge of oil from the oil channel is made efficient in this way. 
     In one advantageous embodiment, the oil channel has a connection to an oil groove constructed on the outer periphery of the hollow shaft stub, via a connection channel with a radial orientation. As a result, oil can be easily routed via the oil groove to the connection channel, and further on to the oil outlet opening of the oil channel, such that oil is moved into the gap between the seal cap and the oil distributor cap. The oil can then be further routed through the oil outlet opening of the oil distributor cap into the inside of a further hollow shaft. 
     In order to simplify an efficient movement of oil, it is advantageous if the oil groove has an orientation running in the axial direction. 
     It is also advantageous if the hollow shaft stub is designed as a sun gear with an outer toothing. In this manner, it is possible to implement a planetary gear step, and thereby also a planetary gear drive. 
     In order to prevent the individual parts from falling apart, it is advantageous if the shaft is fixed axially in the hollow shaft stub via a snap ring. 
     The manufacturing process can be simplified if the oil channel and the connection channel are designed as bore holes with a right angle to each other. 
     It is also advantageous if the oil channels are arranged evenly distributed around the axis of rotation of the hollow shaft stub, and evenly spaced from said axis of rotation. 
     According to aspects illustrated herein, there is provided an insert shaft system, and particularly also to a plug-in connection between a sun gear shaft and the sun gear sitting thereon. Additionally, there is provided a differential having two sun gears, or to a transfer case having a sun gear and a further central shaft, such as a sun gear, a planetary carrier, or a ring gear. 
     The oil distributor cap, which could also be termed a cover cap, covers a shaft stump on the end face thereof. The shaft stump is hollow and configured with parallel oil channels in its cylindrical walls. The oil channels flow into a gap between the cover cap—that is, the oil distributor cap—and the end face of the hollow shaft stub. A gap is produced in this case by spacer elements which are pushed through axially in the direction of the end face of the shaft stump. 
     In other words, the oil distributor cap covers the hollow shaft stub which is configured with at least one oil channel. The oil channel flows into the oil distributor cap. The oil distributor cap which is inserted into the shaft stump, or can sit on the same, tapers like a funnel. The stem of the funnel engages in an oil channel of the shaft stump of a shaft which is positioned axially opposite from the same, or engages in a tube which sits in the opposing shaft. The shafts can rotate with respect to each other. 
     According to aspects illustrated herein, there is provided a device having a hollow shaft or a hollow shaft section, a further shaft sits in the hollow shaft, or a shaft section sits in the hollow shaft section. An annular gap between the hollow shafts and/or hollow shaft sections is closed off axially by means of a cap which sits in the hollow shaft or in the hollow shaft section on the end faces of both shafts and/or shaft sections. In addition, a further cap, with at least one “funnel opening,” sits on the hollow shaft or the hollow shaft section. The further cap collects oil exiting from at least one lubrication channel of the hollow shaft, and conveys the oil to the rest of the system via the funnel opening. 
     These and other objects, advantages and features of the present invention will be better appreciated by those having ordinary skill in the art in view of the following detailed description of the invention in view of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
         FIG. 1  is a first embodiment of an insert shaft system, in a longitudinal cross-section drawing cut along an axis of rotation of the hollow shaft stub; 
         FIG. 2  is a further longitudinal cross-section drawing of an insert shaft system of the invention; 
         FIG. 3  is a further cross-sectional view of an oil distributor cap used in the insert shaft system shown in  FIG. 1  and  FIG. 2 ; 
         FIG. 4  is a further illustration of the oil distributor cap shown in  FIG. 3 ; 
         FIG. 5  is a view of the side of the oil distributor cap which is further from the hollow shaft stub, looking onto the same; 
         FIG. 6  is a view of the oil distributor cap from the side of the hollow shaft stub; 
         FIG. 7  is an enlarged illustration of an end face of the hollow shaft stub, with the oil distributor cap shown in  FIGS. 3 to 6  placed thereon; 
         FIG. 8  is a further longitudinal cross-section drawing of the insert shaft system shown in  FIGS. 1, 2, and 7 , with oil grooves on the outer side of the hollow shaft stub; 
         FIG. 9  is a design of the hollow shaft stub of the embodiments shown in  FIGS. 1, 2, 7 and 8 , as a sun gear, in a perspective drawing mostly from a side which is further from the oil distributor cap; and, 
         FIG. 10  is the sun gear shown in  FIG. 9  from an oil distributor cap side. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects. 
     Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described. 
     The figures are only presented in schematic form for the purpose of clarifying the invention. Elements which are the same in different drawings are indicated by the same reference numbers. 
     A first embodiment of insert shaft system  1  is illustrated in  FIG. 1 . Insert shaft system  1  has hollow shaft stub  2 . Shaft  3  which is constructed as a solid shaft is inserted into the interior of hollow shaft stub  2 . 
     Seal cap  4  is attached on end face  5  of hollow shaft stub  2 . Seal cap  4  has end flange  6  which sits flush with inner side  7  of hollow shaft stub  2 , sealing against the same. End face  8  of seal cap  4  is arranged axially inside hollow shaft stub  2 , or at least is oriented to sit flush with end face  5  of hollow shaft stub  2 . 
     Oil distributor cap  9  is constructed with an axial spacing from seal cap  4 . Oil distributor cap  9  and seal cap  4  form oil distribution chamber  10 . Oil distributor cap  9  also has funnel-like depression  11  which transitions into oil outlet opening  12 . 
     Oil distributor cap  9  is inserted in tube  13  which, in turn, is inserted in hollow shaft  14 , which, in turn, is able to rotate, particularly relative to hollow shaft stub  2 . 
     A toothing is constructed as a wedge toothing on the outer side of shaft  3  and the inner side of hollow shaft stub  2 . Hollow shaft stub  2  and shaft  3  are molded to be complementary to each other. 
     Each of the two elements has groove  15  at the same axial position, in which retaining element  16 , in the form of snap ring  17 , is included. Shaft  3  is fixed in the axial direction relative to hollow shaft stub  2  via snap ring  17 . 
     Oil channels  18  are constructed in hollow shaft stub  2 . Oil channel  18  is connected to oil groove  20  via radially oriented connection channel  19 . 
     Oil groove  20  is constructed on a region of hollow shaft stub  2  which is distant from the end face thereof, and particularly on the outer side, wherein oil groove  20  is oriented in the axial direction. 
     Oil distributor cap  9  is made of steel. Seal cap  4  is likewise made of steel, but can also be made of plastic. It is also possible that oil distributor cap  9  is made of plastic. Light alloys can also be contemplated for both of the components. 
     It can be easily seen in  FIG. 2  that oil distributor caps  18  are constructed on both sides of axis of rotation  21 , and run parallel to the same. Hollow shaft stub  2  is designed as a sun gear. The end face of shaft  3  is indicated by reference number  22 . 
     As can be seen in  FIGS. 3 to 6 , oil distributor cap  9  has funnel-like depression  11  which transitions into oil outlet opening  12 . 
     Projections  23  are constructed at three points on the inner side of oil distributor cap  9  in order to prevent oil distributor cap  9  from sitting flat against the end faces of oil channels  18 . 
     Oil distributor cap  9  has flange region  24  which surrounds end face  5  of hollow shaft stub  2  and which sits flush on the outer side of hollow shaft stub  2  with a press fit. 
     It is also hereby noted that recesses can also be formed in the material of the oil distributor cap, in the place of projections  23 , or a combination of recesses and projections  23  can be used. 
     Oil distributor cap  9  is positioned inside tube  13 , with an allowance for play. However, tube  13  is pressed into hollow shaft  14 . 
       FIG. 8  shows the feed of oil through oil groove  20  into connection channel  19  and then into oil channel  18 , wherein the oil then penetrates into funnel-like depression  11  in oil distributor cap  9 —that is, into oil distribution chamber  10 . 
     As can be clearly seen in  FIGS. 9 and 10 , hollow shaft stub  2  has outer toothing  25  on the outer side thereof, in the manner of a sun gear. 
     The term “oil” in this case is used to mean a hydraulic material which is a fluid. Engine oil, hydraulic oil, and similar oils are included in this context. 
     Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention. 
     LIST OF REFERENCE NUMBERS 
     
         
           1  Insert shaft system 
           2  Hollow shaft stub 
           3  Shaft 
           4  Seal cap 
           5  End face of the hollow shaft stub 
           6  End flange 
           7  Inner side 
           8  End face of the seal cap 
           9  Oil distributor cap 
           10  Oil distribution chamber 
           11  Funnel-like depression 
           12  Oil outlet opening 
           13  Tube 
           14  Hollow shaft 
           15  Groove 
           16  Retaining element 
           17  Snap ring 
           18  Oil channel 
           19  Connection channel 
           20  Oil groove 
           21  Axis of rotation 
           22  End face of the shaft 
           23  Projection 
           24  Flange region 
           25  Outer toothing