Patent Abstract:
A brake hub assembly including a hub defining a central axis, a plurality of guide pins, each of the plurality of guide pins extending from the hub and being generally aligned with the central axis, and a disc having at least two friction surfaces, the disc defining a plurality of guide pin receiving bores, wherein each of the plurality of guide pin receiving bores are positioned to receive an associated one of the plurality of guide pins therethrough such that the disc is moveable relative to the hub along the central axis.

Full Description:
BACKGROUND 
     The present application is directed to multi-disc brake hub assemblies and, more particularly, to multi-disc brake hub assemblies with disc slide pins, one-piece springs or both. 
     Multi-disc brake assemblies typically include a hub, two discs, disc springs and a caliper assembly that includes a piston, a bracket, a fist, an inner pad, a center pad and an outer pad. The hub includes machined slots and the discs include splined teeth that slide within the slots in the hub. As brake pressure is applied, the piston advances the inner pad into the first disc, which advances the center pad into the second disc and ultimately into the outer pad, thereby applying a braking force to the discs. 
     Such multi-disc brake assemblies have presented several problems. In one example, the discs have exhibited a propensity for tipping out of the perpendicular plane, thereby reducing the braking performance. In a second example, corrosion on the discs and hub has inhibited the ability of the discs to freely slide, thereby presenting the risk of discs seizing to the hub. 
     Attempts to solve such problems have included the development of special coatings and treatments for limiting corrosion, as well as redesign adapted to reduce tipping. However, such attempts have resulting in increased costs and more complex manufacturing and assembly requirements. 
     Accordingly, there is a need for a multi-disc brake hub assembly adapted to reduce disc tipping, while providing enhanced disc sliding capabilities at a relatively reduced cost. 
     SUMMARY 
     In one aspect, the disclosed multi-disc brake hub assembly may include a hub defining a central axis, a plurality of guide pins, each of the plurality of guide pins extending from the hub and being generally aligned with the central axis, and a disc having two friction surfaces, the disc defining a plurality of guide pin receiving bores, wherein each of the plurality of guide pin receiving bores are positioned to receive an associated one of the plurality of guide pins therethrough such that the disc is moveable relative to the hub along the central axis. 
     In another aspect, the disclosed multi-disc brake hub assembly may include a hub defining a central axis and including a body and an annulet, the annulet defining a outer side and an inner side relative to the central axis, a plurality of outer guide pins extending from the annulet on the outer side of the hub, each of the plurality of outer guide pins being generally aligned with the central axis, a plurality of inner guide pins extending from the annulet on the inner side of the hub, each of the plurality of inner guide pins being generally aligned with the central axis, an outer disc defining a plurality of guide pin receiving bores positioned to receive an associated one of the plurality of outer guide pins therethrough, wherein the outer disc is moveable along the plurality of outer guide pins relative to the hub, and an inner disc defining a plurality of guide pin receiving bores positioned to receive an associated one of the plurality of inner guide pins therethrough, wherein the inner disc is moveable along the plurality of inner guide pins relative to the hub. 
     Also disclosed is a spring for applying a biasing force to a disc of a multi-disc brake hub assembly including a hub, wherein the spring includes a band adapted to circumferentially engage the hub, at least one biasing feature extending generally radially from the band, and at least one slack-absorbing feature adapted to tighten the band about the hub. 
     Other aspects of the disclosed multi-disc brake hub assembly will become apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of one aspect of the disclosed multi-disc brake hub assembly; 
         FIG. 2  is a front elevational view of the hub of the multi-disc brake hub assembly of  FIG. 1 ; 
         FIG. 3  is a side elevational view of the hub of  FIG. 2 ; 
         FIG. 4  is a front elevational view of the outer disc of the multi-disc brake hub assembly of  FIG. 1 ; 
         FIG. 5  is a side elevational view of the outer disc of  FIG. 4 ; 
         FIG. 6  is a front elevational view of the outer one-piece spring of the multi-disc brake hub assembly of  FIG. 1 ; 
         FIG. 7  is a front perspective view of the multi-disc brake hub assembly of  FIG. 1  in an assembled configuration; 
         FIG. 8  is a front perspective view of a portion of the hub of the multi-disc brake hub assembly of  FIG. 1 , showing the guide pins connected thereto; and 
         FIG. 9  is front elevational view of a portion of the hub of  FIG. 7  showing the outer disc slidably received over the slide pins. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , one aspect of the disclosed multi-disc brake hub assembly, generally designated  10 , may include, among other things, connection bolts  12 ,  14 ,  16 ,  18 ,  20 , an outer disc  22 , a hub  26 , guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42 , an inner disc  44  and, optionally an outer one-piece spring  24  and an inner one-piece spring  44 . The multi-disc brake hub assembly  10  may be connected to the spindle flange  46  of a bearing assembly (not shown) by the connection bolts  12 ,  14 ,  16 ,  18 ,  20 . 
     Referring to  FIGS. 2 and 3 , the hub  26  may include a body  50  and an annulet  52  extending radially from the body  50 . The body  50  may be formed as a generally short cylinder and may define a rotational axis A ( FIG. 3 ), a central bore  54  and a plurality of connection bolt receiving bores  56 ,  58 ,  60 ,  62 ,  64 . The annulet  52  may be connected to, or formed integral with, the body  50  and may define a plurality of guide pin securing bores  66 ,  68 ,  70 ,  72 ,  74 ,  76 ,  78 . In one aspect, the annulet  52  may be positioned generally centrally on the body  50  relative to the axial length of the body  50 . 
     Those skilled in the art will appreciate that the hub  26  may be formed from various rigid materials, such as metal (e.g., steel), using a variety of metal forming processes, such as casting. 
     Referring to  FIGS. 4 and 5 , each of the outer  22  and inner  44  discs (only outer disc  22  is shown in  FIGS. 4 and 5 ) may be shaped as a short, hollow cylinder (i.e., an annulus in front view ( FIG. 4 )) and may include an outer friction surface  80 , an inner friction surface  82 , an outer radial edge  84 , an inner radial edge  86  and a plurality of tabs  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100 . The tabs  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  may be spaced generally equidistantly (or otherwise) from each other and may extend generally radially inward from the inner radial edge  86 . Furthermore, each tab  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  may define a guide pin receiving bore  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114 . The tabs  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  may be formed integrally with the discs  22 ,  44  by, for example, casting or machining the discs. However, those skilled in the art will appreciate that alternative means for forming the tabs  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  may be used without departing from the scope of the present disclosure (e.g., welding tabs to the discs). 
     In one aspect, as shown in  FIG. 9 , the guide pin receiving bores  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114  may be formed in the tabs  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  as generally elongated slots, extending in the radial direction, to accommodate thermal expansion in the radial direction. For example, the elongated slots may be obround in shape, depending upon the shape of the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42 . 
     As shown in  FIG. 8 , the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  may be received through the guide pin securing bores  66 ,  68 ,  70 ,  72 ,  74 ,  76 ,  78  in the hub  26  such that an outer portion  116  of each guide pin extends axially outwardly from the annulet  52  and an inner portion  118  of each guide pin extends axially inwardly from the annulet. While the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  may be press fit into the guide pin securing bores  66 ,  68 ,  70 ,  72 ,  74 ,  76 ,  78 , as shown in  FIG. 7 , those skilled in the art will appreciate that the guide pins may be connected to the hub  26  by alternative means, such as welding, or may be formed integrally with the hub  26 . Alternatively, rather than a single guide pin  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  forming both the outer  116  and the inner  118  portions discussed above, two separate guide pins may be used to form the outer and inner portions. 
     In one aspect, the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  may be formed from a corrosion resistant material, such as stainless steel. In another aspect, the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  may be coated with, or otherwise treated with, a corrosion resistant material. Those skilled in the art will appreciate that the use of corrosion resistant materials may reduce corrosion-induced friction and the risk of disc-to-guide pin seizure. 
     In one aspect, the disclosed multi-disc brake hub assembly  10  may be assembled, as shown in  FIG. 7 , by (1) connecting the inner disc  44  to the hub  26  such that the inner portion  118  of each guide pin  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  is received through an associated guide pin receiving bore  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114  in the inner disc, (2) connecting the outer disc  22  to the hub  26  such that the outer portion  116  of each guide pin  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  is received through an associated guide pin receiving bore  102 ,  104 ,  106 ,  108 ,  110 ,  112 ,  114  in the outer disc, and (3) passing the connection bolts  12 ,  14 ,  16 ,  18 ,  20  through the connection bolt receiving bores  56 ,  58 ,  60 ,  62 ,  64  in the hub  26  to secure the hub to the spindle flange  46  of the knuckle  48 . However, those skilled in the art will appreciate that the disclosed multi-disc brake hub assembly  10  may be assembled in a variety of ways without departing from the scope of the present disclosure. 
     Accordingly, the outer  22  and inner  44  discs may slide generally in the axial direction (axis A,  FIG. 3 ) along the guide pins  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  in response to a braking force applied to the discs  22 ,  44  by a caliper piston (not shown). 
     Optionally, as shown in  FIG. 1 , the multi-disc brake hub assembly  10  may include an outer one-piece spring  24  and/or an inner one-piece spring  28 . 
     Referring to  FIG. 6 , each of the outer  24  and inner  28  one-piece springs (only the outer one-piece spring  24  is shown in  FIGS. 6 ,  8  and  9 ) may include a generally continuous band  120 , features  122 ,  124 ,  126 ,  128 ,  130 ,  132 ,  134  that bias the spring, and features  136 ,  138 ,  140 ,  142 ,  144 ,  146 ,  148  that take up slack in the spring. The spring may also include axial position retention tabs  150 ,  152 ,  154 ,  156 ,  158 ,  160 ,  162  and circumferential position retention tabs  164 ,  166 ,  168 ,  170 ,  172 ,  174 ,  176  having a guide pin opening  178  therein. The one-piece spring  24  may be formed from any appropriate rigid material (e.g., steel or the like). 
     As shown in  FIG. 8 , the outer one-piece spring  24  may be positioned circumferentially over the outer portion  53  ( FIG. 3 ) of the body  50  of the hub  26 . The slack-absorbing features  136 ,  138 ,  140 ,  142 ,  144 ,  146 ,  148  may provide tension to the band  120  by absorbing slack in the band. Therefore, the slack-absorbing features  136 ,  138 ,  140 ,  142 ,  144 ,  146 ,  148  may facilitate a tight tolerance between the outer one-piece spring  24  and the outer portion  53  of the body  50  of the hub  26 . The axial position retention tabs  150 ,  152 ,  154 ,  156 ,  158 ,  160 ,  162  may be received in a circumferential groove  178  extending about the body  50  of the hub  26 , thereby restricting movement of the outer one-piece spring  24  in the axial direction relative to the central axis A ( FIG. 3 ) of the multi-disc brake hub assembly  10 . The circumferential position retention tabs  164 ,  166 ,  168 ,  170 ,  172 ,  174 ,  176  may be positioned to receive (e.g., straddle) an associated guide pin  30 ,  32 ,  34 ,  36 ,  38 ,  40 ,  42  by way of the guide pin opening  178  thereof, thereby restricting circumferential rotation of the outer one-piece spring  24  about the central axis A relative to the hub  26 . 
     As shown in  FIG. 9 , the each biasing feature  122 ,  124 ,  126 ,  128 ,  130 ,  132 ,  134  may engage an associated tab  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  of the outer disc  22  to apply a biasing force (arrow F) to the tab in both the radial and circumferential directions. A chamfer  182  may be formed in each tab  88 ,  90 ,  92 ,  94 ,  96 ,  98 ,  100  to facilitate the interaction between the biasing springs  122 ,  124 ,  126 ,  128 ,  130 ,  132 ,  134  and the tabs. 
     The inner one-piece spring  28  may be applied to the inner portion  55  of the body  50  of the hub  26  in a similar fashion as the outer one-piece spring  24  is applied to the outer portion  53  of the body  50  of the hub  26 . 
     Accordingly, those skilled in the art will appreciate that the outer and inner one-piece springs  24 ,  28  may reduce disc rattle by exerting both a radial and circumferential (relative to axis A) force to the disks  22 ,  44 . Furthermore, those skilled in the art will appreciate that the outer and inner one-piece springs  24 ,  28  may be used with the disclosed multi-disc brake hub assembly  10 , as well as with other (e.g., traditional) multi-disc brake hub assemblies. 
     Although various aspects of the disclosed multi-disc brake hub assembly have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.

Technology Classification (CPC): 5