Patent Publication Number: US-2021167663-A1

Title: Drum brake apparatus for a vehicle air braking system and method of assembling the same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of the pending U.S. patent application Ser. No. 16/051,628 entitled “Drum Brake Apparatus for a Vehicle Air Braking System and Method of Assembling the Same” filed Aug. 1, 2018, the entire disclosure of which is incorporated fully herein by reference. 
    
    
     BACKGROUND 
     The present application relates to vehicle air braking systems, and is particularly directed to a drum brake apparatus for a vehicle air braking system, such as a heavy vehicle air braking system that includes a drum brake assembly, and a method of assembling the same. 
     A typical drum brake assembly includes a brake shoe that engages a wheel drum to transmit brake torque through a brake spider to a wheel axle. One end of the brake shoe is pivotable against an anchor pin that is attached to one side of the brake spider. A cam follower roller is disposed at the other end of the brake shoe. When a service brake application occurs, a camshaft located on the side of the brake spider opposite the anchor pin is actuated to rotate about its longitudinal central axis. As the camshaft rotates about its longitudinal central axis, a cam surface of an S-cam mounted on the camshaft acts against the cam follower roller to pivot the brake shoe about the anchor pin. As the brake shoe pivots about the anchor pin, the lining of the brake shoe frictionally engages the wheel drum to transmit brake torque through the brake spider to the wheel axle and thereby to decelerate and brake the vehicle. 
     Some drum brake assemblies are equipped with an electric wheel end drive motor. The electric wheel end drive motor functions both to propel the vehicle and to generate brake torque to assist in decelerating and braking the vehicle when needed. Accordingly, those skilled in the art continue with research and development efforts in drum brake assemblies including drum brake assemblies with electric wheel end drive motors. 
     SUMMARY 
     In accordance with one example embodiment, a drum brake apparatus is provided for a vehicle air braking system. The drum brake apparatus comprises a wheel drum having a first interior chamber. The drum brake apparatus also comprises a drum brake assembly disposed in the first interior chamber of the wheel drum and mounted on inboard side of the wheel drum. The drum apparatus further comprises a brake drum adapter mounted on outboard side of the wheel drum and providing a second interior chamber in which an electric drive motor can be disposed. The drum brake apparatus also comprises a wheel hub disposed in the second interior chamber of the brake drum adapter and to which a wheel rim can be mounted. 
     In accordance with another example embodiment, a drum brake apparatus is provided for a vehicle air braking system having an electric drive motor. The drum brake apparatus comprises a wheel drum. The drum brake apparatus also comprises a brake drum adapter coupled with the wheel drum and cooperating with the wheel drum to form a structure that can house the electric drive motor. 
     In accordance with another example embodiment, an assembly method is provided for a vehicle having an axle assembly. The assembly method comprises fastening a drum brake to a brake flange of the axle assembly, coupling an electric drive motor to an axle of the axle assembly, and routing electrical lines through a brake spider and the brake flange of the axle assembly. The assembly method also comprises attaching the electrical lines to the electric drive motor, coupling a wheel hub to a spindle of the axle assembly, and coupling a combined structure of a brake drum portion and a brake drum adapter portion between the drum brake and the wheel hub. The assembly method further comprises mounting a wheel rim on wheel studs of the wheel hub and against one end of the brake drum adapter of the combined structure. 
     In accordance with another example embodiment, a drum brake apparatus is provided for a vehicle air braking system. The drum brake apparatus comprises a brake drum adapter for providing an interface between a wheel drum and a wheel hub and housing one or more brake components associated with the vehicle air braking system. The brake drum adapter has a plurality of vent openings through which air can flow to cool a brake component housed within the brake drum adapter. 
     In accordance with another example embodiment, an apparatus is connectable with an electric wheel end drive motor. The apparatus comprises a wheel axle. The apparatus also comprises a brake spider having an inboard side and an outboard side and mounted on a portion of the wheel axle. The apparatus further comprises a brake flange having an inboard side and an outboard side and mounted on another portion of the wheel axle on the inboard side of the brake spider. The brake spider and the brake flange have aligned passages through which electrical lines can enter from the inboard side of the brake flange and exit from the outboard side of the brake spider so that the electrical lines can interface with the electric wheel end drive motor. 
     In accordance with another example embodiment, a drum brake apparatus is provided for a vehicle air braking system having an electric drive motor. The drum brake apparatus comprises a wheel hub supporting the electric drive motor. The drum brake apparatus also comprises means for surrounding at least a portion of the wheel hub and the electric drive motor to protect the wheel hub and the electric drive motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example drum brake apparatus including a brake drum adapter constructed in accordance with an embodiment. 
         FIG. 2  is an exploded view of components including the brake drum adapter of the drum brake apparatus of  FIG. 1   
         FIG. 3  is a sectional view looking approximately along line  3 - 3  shown in  FIG. 1 . 
         FIG. 4  is an enlarged view of the brake drum adapter shown in  FIG. 2 . 
         FIG. 4A  is a perspective view similar to  FIG. 4 , and showing a brake drum adapter constructed in accordance with another embodiment. 
         FIG. 4B  is a perspective view similar to  FIG. 4 , and showing a brake drum adapter constructed in accordance with another embodiment. 
         FIG. 4C  is a perspective view similar to  FIG. 4 , and showing a brake drum adapter constructed in accordance with another embodiment. 
         FIG. 4D  is a perspective view similar to  FIG. 4 , and showing a brake drum adapter constructed in accordance with another embodiment. 
         FIG. 5A  is a perspective view of an elongated brake drum without adapter constructed in accordance with an embodiment. 
         FIG. 5B  is a perspective view looking approximately in the direction of arrow “ 5 B” shown  FIG. 5A . 
         FIG. 6  is a perspective view looking approximately in the direction of arrow “ 6 ” shown in  FIG. 1 . 
         FIG. 7A  is an elevational view looking approximately along line  7 A- 7 A shown in  FIG. 2 . 
         FIG. 7B  is a perspective view of an enlarged portion of  FIG. 7A , which is designated with rectangle “ 7 B” in  FIG. 7A . 
         FIG. 8  is a flow diagram depicting an example method of assembling the drum brake apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a perspective view of an example drum brake apparatus  100  including a brake drum adapter  150  constructed in accordance with an embodiment.  FIG. 2  is an exploded view of components including the brake drum adapter  150  of the drum brake apparatus  100  of  FIG. 1 . 
     The drum brake apparatus  100  comprises a wheel drum  110 , and a drum brake assembly  120  mounted on inboard side (i.e., the inboard side of the vehicle) of the wheel drum  110 . The drum brake apparatus  100  also comprises a wheel hub  130  disposed on outboard side of the wheel drum  110 , and to which a wheel rim  140  can be mounted. The wheel hub  130  has a number of wheel studs  134 . 
     A brake spider  184  is disposed on inboard side of the drum brake assembly  120 . The brake spider  184  faces an axle assembly  180  having a wheel axle  182  and a brake flange  186  mounted on a portion of the wheel axle  182 . The brake spider  184  is mounted on another portion of the wheel axle  182 . 
     The drum brake apparatus  100  further comprises the brake drum adapter  150  which is mounted on outboard side of the wheel drum  110 . The brake drum adapter  150  is coupled with the wheel drum  110  and cooperates with the wheel drum  110  to form a structure that can house an electric wheel end drive motor  190  for providing driving force and brake torque when needed. The electric drive motor  190  may comprise any electric drive motor. The brake drum adapter  150  is coupled to the wheel drum  110  using a suitable fastening mechanism, such as threaded studs and nuts for example. Other types of fastening mechanisms are possible. 
     Referring to  FIG. 3 , a sectional view looking approximately along line  3 - 3  shown in  FIG. 1  is illustrated. The wheel drum  110  has a first interior chamber  112 . The drum brake assembly  120  is disposed in the first interior chamber  112  of the wheel drum  110 . The brake drum adapter  150  defines a second interior chamber  152  that is in communication with the first interior chamber  112 . The wheel hub  130  is disposed in the second interior chamber  152  of the brake drum adapter  150 . The electric drive motor  190  is also disposed in the second interior chamber  152  of the brake drum adapter  150 . 
     More specifically, the electric drive motor  190  is disposed on inboard side of the second interior chamber  152  of the brake drum adapter  150 . The wheel hub  130  is disposed on outboard side of the second interior chamber  152  of the brake drum adapter  150 . The wheel drum  110  comprises cast iron material, and the brake drum adapter  150  comprises cast aluminum material. It is conceivable that the wheel drum  110  may comprise a different material, and that the brake drum adapter  150  may comprise a different material. The wheel drum  110  has a longitudinal central axis  132 . The brake drum adapter  150  has a longitudinal central axis  153  that is concentric with the longitudinal central axis  132  of the wheel drum  110 . 
     Referring to  FIG. 4 , an enlarged view of the brake drum adapter  150  of  FIG. 2  is shown. The brake drum adapter  150  includes a tapered circumferential surface  154  that extends between a larger radius edge  156  on inboard side of the brake drum adapter  150  and a smaller radius edge  158  on outboard side of the brake drum adapter  150  to form a substantially frustoconical shape of the brake drum adapter  150 . The brake drum adapter  150  includes an end surface  160  disposed at the smaller radius edge  158 . The end surface  160  has a number of holes  162  that receive the wheel studs  134  of the wheel hub  130  (see  FIG. 3 ). 
     The tapered circumferential surface  154  has a plurality of vent openings through which air can pass to cool the electric drive motor  190 . The plurality of vent openings includes a first set  166  of oval-shaped openings adjacent to the larger radius edge  156 , and a second set  168  of oval-shaped openings adjacent to the smaller radius edge  158 . The shape and size of the first set  166  of oval-shaped openings and the shape and size of the second set  168  of oval-shaped openings may vary. The first set  166  of oval-shaped openings and the second set  168  of oval-shaped openings alternate along the circumferential extent of the brake drum adapter  150 . The first set  166  of oval-shaped openings are oval along the circumferential extent of the brake drum adapter  150 , and the second set  168  of oval-shaped openings are oval along the longitudinal extent of the brake drum adapter  150 . Accordingly, the first set  166  of openings and the second set  168  of openings are transverse to each other. 
     Referring to each of  FIGS. 4A, 4B, 4C, and 4D , a perspective view of a brake drum adapter constructed in accordance with another embodiment is illustrated. As shown in  FIG. 4A , a brake drum adapter  150   a  includes a tapered circumferential surface  154   a  that has a plurality of vent openings. The plurality of vent openings includes a first set  166   a  of oval-shaped openings adjacent to a larger radius edge  156   a  of the brake drum adapter  150   a , and a second set  168   a  of oval-shaped openings adjacent to a smaller radius edge  158   a  of the brake drum adapter  150   a . The shape and size of the first set  166   a  of oval-shaped openings and the shape and size of the second set  168   a  of oval-shaped openings may vary. The first set  166   a  of oval-shaped openings are oval along the circumferential extent of the brake drum adapter  150   a , and the second set  168   a  of oval-shaped openings are also oval along the circumferential extent of the brake drum adapter  150   a . Accordingly, the first set  166   a  of openings and the second set  168   a  of openings are parallel to each other around the circumferential extent of the brake drum adapter  150   a.    
     As shown in  FIG. 4B , a brake drum adapter  150   b  includes a tapered circumferential surface  154   b  that has a plurality of vent openings. The plurality of vent openings includes a first set  166   b  of oval-shaped openings adjacent to a larger radius edge  156   b  of the brake drum adapter  150   b , and a second set  168   b  of oval-shaped openings adjacent to a smaller radius edge  158   b  of the brake drum adapter  150   b . The shape and size of the first set  166   b  of oval-shaped openings and the shape and size of the second set  168   b  of oval-shaped openings may vary. The first set  166   b  of oval-shaped openings and the second set  168   c  of oval-shaped openings alternate along the circumferential extent of the brake drum adapter  150   b . The first set  166   b  of oval-shaped openings are oval along the longitudinal extent of the brake drum adapter  150   b , and the second set  168   b  of oval-shaped openings are also oval along the longitudinal extent of the brake drum adapter  150   b . Accordingly, the first set  166   b  of openings and the second set  168   b  of openings are parallel to each other along the longitudinal extent of the brake drum adapter  150   b.    
     As shown in  FIG. 4C , a brake drum adapter  150   c  includes a tapered circumferential surface  154   c  that has a plurality of vent openings. The plurality of vent openings includes a first set  166   c  of circular-shaped openings adjacent to a larger radius edge  156   c  of the brake drum adapter  150   c , and a second set  168   c  of circular-shaped openings adjacent to a smaller radius edge  158   c  of the brake drum adapter  150   b . The shape and size of the first set  166   c  of circular-shaped openings and the shape and size of the second set  168   c  of circular-shaped openings may vary. The first set  166   c  of circular-shaped openings and the second set  168   b  of circular-shaped openings alternate along the circumferential extent of the brake drum adapter  150   c.    
     As shown in  FIG. 4D , a brake drum adapter  150   d  includes a tapered circumferential surface  154   d  that has a plurality of vent openings. The plurality of vent openings includes a first set  166   d  of triangular-shaped openings adjacent to a larger radius edge  156   d  of the brake drum adapter  150   d , and a second set  168   d  of triangular-shaped openings adjacent to a smaller radius edge  158   d  of the brake drum adapter  150   d . The shape and size of the first set  166   d  of triangular-shaped openings and the shape and size of the second set  168   d  of triangular-shaped openings may vary. The first set  166   d  of triangular-shaped openings and the second set  168   d  of triangular-shaped openings alternate along the circumferential extent of the brake drum adapter  150   d . The first set  166   d  of triangular-shaped openings “point” toward the outboard side of the vehicle, and the second set  168   d  of triangular-shaped openings “point” toward the inboard side of the vehicle. 
     Referring to  FIG. 5A , a perspective view of an elongated brake drum without adapter  500  constructed in accordance with an embodiment is illustrated.  FIG. 5B  is a perspective view looking approximately in the direction of arrow “ 5 B” shown  FIG. 5A . The elongated brake drum without adapter  500  comprises an integrated, single piece of cast iron material. It is conceivable that the elongated brake drum without adapter  500  comprise a different material. 
     The elongated brake drum without adapter  500  includes a brake drum portion  530  and a brake drum adapter portion  550 . The elongated brake drum without adapter  500  of  FIGS. 5A and 5B  has the functionality of the brake drum  130  and the functionality of the brake drum adapter  150  of  FIGS. 1-4  described hereinabove. 
     Referring to  FIG. 6 , a perspective view looking approximately in the direction of arrow “ 6 ” shown in  FIG. 1  is illustrated.  FIG. 7A  is an elevational view looking approximately along line  7 A- 7 A shown in  FIG. 2 .  FIG. 7B  is a perspective view of an enlarged portion of  FIG. 7A , which is designated with rectangle “ 7 B” in  FIG. 7A . The brake spider  184  and the brake flange  186  have aligned passages through which coolant lines and electrical lines can enter from the inboard side of the brake flange  186  and exit from the outboard side of the brake spider  184  so that the coolant lines and electrical lines can interface with the electric drive motor  190 . 
     More specifically, as best shown in  FIG. 7B , the brake spider  184  and the brake flange  186  have a number of aligned passages through which coolant lines can enter from the inboard side of the brake flange  186  and exit from the outboard side of the brake spider  184  so that the coolant lines can interface with the electric drive motor  190 . The brake spider  184  and the brake flange  186  have (i) a first pair  170  of aligned passages through which coolant lines  171  can enter from the inboard side of the brake flange  186  and exit from the outboard side of the brake spider  184 , (ii) a second pair  172  of aligned passages through which electrical control lines  173  can enter from the inboard side of the brake flange  186  and exit from the outboard side of the brake spider  184 , and (iii) a third pair  174  of aligned passages through which electrical power lines  175  can enter from the inboard side of the brake flange  186  and exit from the outboard side of the brake spider  184 . The second pair  172  of aligned passages lie substantially between the first pair  170  of aligned passages, and the third pair  174  of aligned passages lie substantially between the second pair  172  of aligned passages. 
     Referring to  FIG. 8 , a flow diagram  800  depicting an example method of assembling the drum brake apparatus  100  of  FIG. 1  is illustrated. In block  810 , a drum brake is fastened to a brake flange of an axle assembly. The process proceeds to block  820  in which an electric drive motor is coupled to an axle of the axle assembly. Then in block  830 , electrical lines are routed through a brake spider and a brake flange of the axle assembly. In block  840 , the electrical lines are attached to the electric drive motor. The electrical lines include a number of power lines and a number of control lines. Then the process proceeds to block  850 . 
     In block  850 , a wheel hub is coupled to a spindle of the axle assembly. Then in block  860 , a combined structure of a brake drum portion and a brake drum adapter portion is coupled between the drum brake and the wheel hub. The process then proceeds to block  870  in which a wheel rim is mounted on wheel studs of the wheel hub and against one end of the brake drum adapter of the combined structure. The process then ends. 
     In some embodiments, the assembly method further comprises routing coolant lines through the brake spider and the brake flange of the axle assembly, and attaching the coolant lines to the electric drive motor. 
     In some embodiments, routing electrical lines and routing coolant lines includes routing a pair of coolant lines, a pair of electrical control lines substantially between the pair of coolant lines, and a pair of electric power lines substantially between the pair of electrical control lines through the brake spider and the brake flange of the axle assembly. 
     In some embodiments, coupling a combined structure of a brake drum portion and a brake drum adapter portion between the drum brake and the wheel hub includes positioning the brake drum portion around the drum brake and positioning the brake drum adapter portion around the wheel hub. 
     In some embodiments, the assembly method further comprises fastening the brake drum portion and the brake drum adapter portion together before the combined structure is coupled between the drum brake and the wheel hub. 
     In some embodiments, fastening the brake drum portion and the brake drum adapter portion together before the combined structure is coupled between the drum brake and the wheel hub includes fastening the brake drum portion made of cast iron material and the brake drum adapter portion made of aluminum material together before the combined structure is coupled between the drum brake and the wheel hub. 
     In some embodiments, coupling a combined structure of a brake drum portion and a brake drum adapter portion between the drum brake and the wheel hub includes coupling the brake drum portion and the brake drum adapter portion as an integrated, single piece of cast iron material between the drum brake and the wheel hub. 
     It should be apparent that the brake drum adapter  150  provides an interface between the wheel drum  110  and the wheel hub  130  and houses one or more brake components associated with the vehicle air braking system. The brake drum adapter  150  not only protects the wheel hub  130  and the electric drive motor  190  by providing a structure that surrounds at least a portion of the wheel hub  130  and the electric drive motor  190 , but also has the plurality of vent openings  166 ,  168  through which air can flow to cool a brake component housed in a chamber defined within the brake drum adapter  150 . 
     It should also be apparent that a drum brake apparatus constructed in accordance with the above-described example embodiment combines the advantages of a brake drum adapter made of cast aluminum material and a brake drum made of cast iron material. 
     It should further be apparent that a drum brake apparatus constructed in accordance with the above-described example embodiments is relatively easy to fabricate and assemble. The drum brake apparatus can be installed in retrofit applications as well as new production applications. 
     Although the above description describes the drum brake apparatus  100  being used in a heavy vehicle such as a truck, it is conceivable that the drum brake apparatus  100  may be used in other types of commercial vehicles, such as busses for example. 
     While the present disclosure has been illustrated by the description of example processes and system components, and while the various processes and components have been described in detail, applicant does not intend to restrict or in any way limit the scope of the appended claims to such detail. Additional modifications will also readily appear to those skilled in the art. The disclosure in its broadest aspects is therefore not limited to the specific details, implementations, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general concept.