Abstract:
A flanged boot having a rolling bearing interface suitable for connection to two mechanical components which are movable with respect to each other, in terms of both rotational and axial movements. The flanged boot has a first annular flange at one end and a second annular at the other end. A rolling bearing, such as for example a roller (needle) or ball bearing, is press-fit onto a suitably configured structure of a first mechanical component. One of the first and second annular flanges is interfaced sealingly with respect to the rolling bearing. The other of the first and second annular flanges is sealingly connected to a second mechanical component. Either of the first or second mechanical components may be considered to be moving relative to the other.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to flexible boots used to protectively envelope mechanical components, and more particularly to a boot interfaced with mechanical components which are rotatably and axially movable relative to each other.  
         BACKGROUND OF THE INVENTION  
         [0002]    Mechanical components which require a clean environment in order to function properly are protectively enveloped by boots which are usually made of a convoluted (or pleated) elastomeric material. Typically, the environment of application of boots involves mechanical components which are lubricated and have certain movement. The movement may involve either or both of rotation in unison with each other and straight-line (axial) movement relative to each other. Typically, the boot is sealingly connected at its one end to one mechanical component, and connected at its other end to the other mechanical component. The boot has flexibility and sealing properties which provide an environmentally protected space therewithin. The boot serves to maintain a clean environment therewithin free of all exterior contaminants, while at the same time confining the lubricants to the boot interior. An example of an automotive application, would be at the constant velocity joint of front wheel drive vehicles.  
           [0003]    While boots are used in a variety of automotive applications, this is not universally the case for technical reasons, as for example in certain driveline configurations. In this regard, beam axle applications frequently utilize a splined slip mechanism for the connection from the propshaft (also known as a drive shaft) to the powertrain output.  
           [0004]    An interesting example is a splined slip mechanism, which includes a female splined slip yoke shaft meshingly mated to a male splined output shaft. The slip yoke is connected to the propeller shaft via a U-joint, and the output shaft is connected with the transmission. This splined slip mechanism typically utilizes a transmission housing bushing to guide the machined outside diameter of the slip yoke shaft, and this bushing interface is protected by an annular seal. The annular seal is seated in an annular seal seat of the transmission housing in concentric relation to the slip yoke and output shafts, and thereby serves to protect the interface between the transmission housing and the slip yoke shaft from contamination during both rotary and axial movements of the slip yoke relative to the bushing. However, even with modern seal technology applied to this interface, there remains the possibility of susceptibility to seal wear due to contamination ingress, which results in transmission/transfercase fluid leaks and other concerns. A boot is not suitable for this application because of the relative rotation of the mechanical components (that is, the transmission housing relative to the slip yoke shaft).  
           [0005]    Accordingly, it would be beneficial if somehow a boot could be adapted to an application where relative axial and rotational movements of the mechanical components are involved.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention is a flanged boot having a rolling bearing interface suitable for connection to two mechanical components which are movable with respect to each other, both in terms of rotational and axial movements.  
           [0007]    The flanged boot is composed of a conventional boot material, as for example a convoluted (pleated) flexible elastomeric material, having at one end a first annular flange and at the other end a second annular flange. Preferably, the first annular flange is an integral boot flange and the second annular flange is a connector flange sealingly interfaced with the second end.  
           [0008]    A rolling bearing having inner and outer races, such as for example a roller bearing or ball bearing, has one race thereof connected to a suitably configured structure of a first mechanical component. One of the first and second annular flanges is sealingly interfaced with the other race of the rolling bearing. The other of the first and second flanges of the flanged boot is sealingly connected to a second mechanical component.  
           [0009]    Either of the first or second mechanical components may be considered to be moving relative to the other, in the sense of relation to a coordinate system, as for example a coordinate system fixed in space relative to the frame of a motor vehicle. In this regard, the first mechanical component could be, for example, a transmission housing which is “stationary” and the second mechanical component could be, for example, a component shaft of propeller shaft having rotational and axial movements relative to the transmission housing. Further in this regard, either of the first and second annular flanges can be connected to, respectively, either of the first and second mechanical components, wherein in certain arrangements the flanged boot is viewed as being “stationary” and in other arrangements the flanged boot is viewed as being “rotating” depending on which of the mechanical components is viewed as “rotating” and whether or not that component is interfaced with the rolling bearing.  
           [0010]    Accordingly, it is an object of the present invention to provide a flexible boot for environmentally protecting a connection between first and second mechanical components having rotational movement with respect to each other, wherein the boot is interfaced with one of the mechanical components via a rolling bearing.  
           [0011]    This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a sectional side view of a bearing interfaced flanged boot according to the present invention, shown in a first operational example with respect to a splined slip mechanism involving a slip yoke shaft, a transmission case and an output shaft of the transmission.  
         [0013]    [0013]FIG. 2 is a sectional side view as in FIG. 1, wherein the slip yoke has axially moved relative to the output shaft.  
         [0014]    [0014]FIG. 3 is a sectional view seen along line  3 - 3  of FIG. 2.  
         [0015]    [0015]FIG. 4 is a sectional view seen along line  4 - 4  of FIG. 2.  
         [0016]    [0016]FIG. 5 is a sectional view seen along line  5 - 5  of FIG. 2.  
         [0017]    [0017]FIG. 6 is a sectional side view of the bearing interfaced flanged boot according to the present invention, shown in a second operational example with respect to the splined slip mechanism.  
         [0018]    [0018]FIG. 7 is a sectional side view as in FIG. 6, wherein the slip yoke has axially moved relative to the output shaft.  
         [0019]    [0019]FIG. 8 is a sectional view seen along line  8 - 8  of FIG. 7.  
         [0020]    [0020]FIG. 9 is a sectional view seen along line  9 - 9  of FIG. 7.  
         [0021]    [0021]FIG. 10 is a sectional view seen along line  10 - 10  of FIG. 7. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    Referring now to the Drawing, FIGS. 1 through 5 depict a first example of operation of the bearing interfaced flanged boot  100  according to the present invention, and FIGS. 6 through 10 depict a second example of operation of the bearing interfaced flanged boot according to the present invention. In either example, the bearing interfaced flanged boot  100  is interfaced with a slip yoke mechanism  102  having relatively rotating and axially moving mechanical components in the form of a transmission (transfer case, or gearbox, etc.) housing  104  and a slip yoke shaft  106 a of a slip yoke  106 .  
         [0023]    The slip yoke  106  has slip yoke ears  106 b for forming a component of a U-joint connection to a propeller (drive) shaft. The slip yoke  106  is drivingly engaged with respect to an output shaft  108  of a transmission (transfer case, gear box, etc.)  115  having the transmission housing  104 . The slip yoke shaft  106   a  is female, having internal splines  106   s . The output shaft  108  is male, having external splines  108   s . The internal and external splines  106   s ,  108   s  are gearingly meshed with each other so that rotation of the output shaft is transmitted in unison to the slip yoke, while allowing the slip yoke to axially move relative to the output shaft (see comparatively FIGS. 1 and 2, and FIGS. 6 and 7).  
         [0024]    As mentioned hereinabove, it is conventional practice to seal the slip yoke mechanism via an annular seal seated in an annular seal seat of the transmission housing. As will be seen hereinbelow, with no, or relatively little, modification of the conventional structures of the transmission housing and slip yoke, the bearing interfaced flanged boot  100  may be sealingly interfaced therewith. In this regard, the bearing interfaced flanged boot  100  solves the problem of accommodating relative rotation between mechanical components via a rolling bearing  110  sealingly interfaced with a flanged boot  112 . Accordingly, at a selected location of relative rotation between the mechanical components, a rolling bearing interface  125  is provided which allows the flanged boot to be sealingly interfaced with the relatively rotating mechanical components, in this example one mechanical component is the transmission housing  104 , and the other mechanical component is the slip yoke shaft  106   a.    
         [0025]    The flanged boot  112  has generally a cylindrical shape having annular convolutions, or annular pleats,  112   c , which allow for its axial expansion, defined by a sidewall  112   s  composed of a conventional, flexible elastomeric material. One end  112   a  of the flanged boot  112  has an annular boot flange  112   f . At the other end  112   b  of the flanged boot  112  is a ribbed mouth  112   m . An annular connector flange  114  is sealingly interfaced interiorly with respect to the ribbed mouth  112   m , which may be aided by a plastic insert  112   i . The connector flange  114  may be press-fit or be internally molded. The connector flange  114  may be composed of plastic or metal (a corrosion resistant metal being preferred).  
         [0026]    Referring now to FIGS. 1 through 5, the first exemplar application of the bearing interfaced flanged boot  100  will be detailed with respect to the slip yoke mechanism  102 .  
         [0027]    The transmission housing  104  has a bushing  104   b  and an adjacent recessed annular seal seat  116 . A generally conventional annular seal  118  is provided which has an outer surface  118   a  that is pressed into the free (or open) end  114   a  of the connector flange  114 . Then the free end  114   a  of the connector flange  114  (inherently along with the interiorly disposed annular seal  118 ), is press-fit into the annular seal seat  116 .  
         [0028]    The above mentioned rolling bearing  110  has an inner race  110   a  that is rollingly rotatable with respect to an outer race  110   b , as for example in the form of a roller (needle) bearing or a ball bearing. The slip yoke  106  has an annular bearing seat  120  onto which the inner race  110   a  of the rolling bearing  110  is press-fit.  
         [0029]    The slip yoke shaft  106   a  is placed into the transmission housing  104  at the seal seat  116  such that the slip yoke shaft receives thereinside the output shaft  108 , wherein the internal splines  106   s  gearingly mesh with respect to the external splines  108   s , wherein the machined (polished) outside surface of the slip yoke shaft guidably abuts the bushing  104   b , and wherein the annular seal  118  sealingly abuts the outside surface of the slip yoke shaft. The boot flange  112   f  of the flanged boot  112  is then placed over the outer race  110   b  of the rolling bearing  110 . Next, the bearing flange  112   f  is clamped sealingly onto the outer race  110   b  by tightening of an annular clamp  122 .  
         [0030]    In the application shown at FIGS. 1 through 5, the flanged boot  112  is viewed as being “stationary” in the sense that it is stationary with respect to the transmission housing  104 , while the slip yoke  106  rotates relative thereto. The bearing interfaced flanged boot  100  flexibly accommodates axial movements of the slip yoke  106  relative to the transmission housing  104 , as well as bearingly accommodates rotation as between the transmission housing and the slip yoke, all the while providing a perfectly sealed environment therewithin.  
         [0031]    Referring now to FIGS. 6 through 10, the second exemplar application of the bearing interfaced flanged boot  100  will be detailed with respect to the slip yoke mechanism  102 .  
         [0032]    The transmission housing  104  again has the bushing  104   b  and the adjacent recessed annular seal seat  116 ′ (which may be enlarged from that shown in FIGS. 1, 2 and  3 ). The flanged boot  112  again has the boot flange  112   f  and the annular connector flange  114  sealingly interfaced interiorly with respect to the ribbed mouth  112   m , preferably aided by the plastic insert  112   i.    
         [0033]    The generally conventional annular seal  118 ′ is provided (perhaps smaller in scale than that depicted in FIGS. 1, 2 and  3 , depending upon the size of the seal seat  116 ) which has an outer surface  118   a  that is pressed into the free (open) end  114   a  of the connector flange  114  (the free end would be resized commensurately with respect to any resizing of the seal seat and annular seal). A rolling bearing  110 , as above exemplified by a roller (needle) or ball bearing, is press-fit into the seal seat  116 ′ such that the outer race  110   b  abuts the seal seat. Then the free end  114   a  of the connector flange  114  (inherently along with the interiorly disposed annular seal  118 ), is placed into the annular seal seat  116  by a press-fit with respect to the inner race  110   a  of the rolling bearing  110 .  
         [0034]    The slip yoke shaft  106   a  is placed into the transmission housing  104  in the manner recounted hereinabove with respect to FIGS. 1 through 5, wherein the internal splines  106   s  gearingly engage the external splines  108   s , wherein the slip yoke shaft guidably abuts the bushing  104   b , and wherein the slip yoke shaft is sealed by the annular seal  118 ′. The boot flange  112   f  of the flanged boot  112  is then placed over an annular flange seat  120 ′ of the slip yoke shaft  106   a . Next, the boot flange  112   f  is clamped sealingly onto the flange seat  120 ′ by tightening of an annular clamp  122 ′.  
         [0035]    In the application shown at FIGS. 6 through 10, the flanged boot  112  is viewed as being “rotational” in that it rotates with respect to the transmission housing  104 , while it is stationary with respect to the slip yoke  106  (which itself rotates relative to the transmission housing). The bearing interfaced flanged boot  100  flexibly accommodates axial movements of the slip yoke  106  relative to the transmission housing  104 , as well as bearingly accommodates rotation as between the transmission housing and the slip yoke, all the while providing a perfectly sealed environment therewithin.  
         [0036]    The superior benefit of either application is the complete sealing of the polished exterior surface of the slip yoke shaft, keeping away all contamination. And, since the annular seal will not encounter any debris, its life would be dramatically improved (over a conventional application in which it is exposed).  
         [0037]    To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.