Patent Publication Number: US-2023150473-A1

Title: Connection for brake system housing

Description:
TECHNICAL FIELD 
     The present invention relates generally to braking systems and, in particular, relates to a connection for coupling a fluid reservoir to a brake system housing. 
     BACKGROUND 
     Currently, brake system master cylinders are equipped with a brake fluid reservoir installed on one or both of the master cylinder&#39;s supply fittings, depending on whether the master cylinder is simple or tandem. The brake fluid in the brake fluid reservoir is discharged during the braking and electronic stability program (ESP) system operation phase passes freely from the reservoir into the chamber or chambers of the master cylinder. It is desirable to prevent leakage of brake fluid from the master cylinder-fluid reservoir interface during braking, filling, and leak testing operations. 
     SUMMARY 
     In one example, a connection for delivering fluid to a brake system housing having a cavity includes a fluid reservoir having a port extending along a centerline and configured to be received in the cavity. A collar extends around the port. A grommet extends around the port and is received in the cavity for forming a fluid-tight seal between the port and the brake system housing. The grommet includes a flange extending radially to an outermost surface positioned radially inside the collar. 
     In another example, a connection for delivering fluid to a brake system housing having a cavity includes a fluid reservoir including a port extending along a centerline and configured to be received in the cavity. A collar encircles the port. An elastically deformable grommet extends around the port and is received in the cavity for forming a fluid-tight seal between the port and the brake system housing. The grommet includes a flange extending radially to an outermost surface positioned radially inside the collar. 
     Other objects and advantages and a fuller understanding of the invention will be had from the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic illustration of a portion of an example braking system including a fluid connection in accordance with the present invention. 
         FIG.  2    is an enlarged view of a portion of  FIG.  1   . 
         FIG.  3    is an enlarged, modified view of a portion of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates generally to braking systems and, in particular, relates to a connection for coupling a fluid reservoir to a brake system housing.  FIGS.  1 - 3    illustrate an example fluid connection  10  in accordance with the present invention. Referring to  FIG.  1   , the connection  10  helps to fluidly couple a fluid reservoir  20  to a brake system  80 . 
     In this example, the brake system  80  is a master cylinder assembly that pressurizes brake fluid for delivery to brakes associated with vehicle wheels (not shown) in the manner generally indicated by the arrows F. The brake system, however, could alternatively be an integrated, electrohydraulic brake apply control unit (not shown) or any other brake system needing fluid connection to a brake fluid reservoir  20 . In any case, the fluid reservoir  20  includes a housing  22  defining a chamber  24  for storing brake fluid. 
     The master cylinder assembly  80  includes a housing  82  defining a passage  84 . Primary and secondary piston assemblies  90 ,  100  are provided in the passage  84  and cooperate to pressurize brake fluid from the reservoir  20  in a known manner. Ports  30  extending from the housing  22  help to fluidly connect the chamber  24  of pressurized fluid to the passage  84 . 
     The fluid connection  10  couples the reservoir  20  to the master cylinder assembly  80  in a fluid-tight manner to help prevent leaking of pressurized brake fluid from the reservoir. Although the description of the connection  10  is limited to a single port  30  (the right or first port as shown in  FIG.  1   ), it will be appreciated that the connection likewise applies to the other port (the left or second port shown in  FIG.  1   ). In any case, the connection  10  includes the port  30 . 
     Referring to  FIG.  2   , the port  30  extends from the housing  22  along a centerline  32  and defines a passage  34  in fluid communication with the chamber  24 . A collar  40  also extends from a surface  50  of the housing  22  and around the port  30 . In one example, the port  30  and collar  40  are circular and, thus, the collar can encircle and be concentric with the port. Other shapes for the port  30  and collar  40  are contemplated. Moreover, the collar  40  can constitute a continuous projection extending around the port  30  or multiple, spaced-apart projections that collectively extend around the port. In any case, the collar  40  includes an axial end surface  42 , an inner surface  44 , and an outer surface  46 . 
     The housing  82  of the master cylinder assembly  80  includes a cavity  106  for receiving the port  30 . The cavity  106  includes a recess or countersink  108  defined by an end surface  110  and an outer surface  112 . The cavity  106  is in fluid communication with the passage  84  (not shown). 
     The connection  10  includes a grommet  120  for sealing the interface between the port  30  and the housing  82  within the cavity  106 . The grommet  120  is tubular and includes a sidewall  122  having an inner surface  124  defining a passage  126 . The passage  126  can receive a fluid control valve (not shown). The sidewall  122  can be cylindrical or conical. Regardless, the grommet  120  also includes an outer surface  130 . The grommet  120  is made from an elastically deformable material, such as rubber. 
     A flange  136  extends radially outward from the sidewall  122  and terminates at an outer surface  138 . Consequently, the outer surface  138  defines the radially outermost surface of the flange  136 . The flange  136  also includes opposing first and second end surfaces  140 ,  142 . The second surface  142  is tapered such that the thickness of the flange  136  decreases in a direction extending towards the passage  126 . 
     When the connection  10  is assembled, the grommet  120  is positioned within the cavity  106  such that the first end surface  140  of the flange  136  abuts the end surface  110  of the countersink  108 . The outer surface  138  of the flange  136  is positioned adjacent to or abuts the outer surface  112  of the countersink  108 . Consequently, the flange  136  and, thus, the grommet  120  is prevented from moving laterally (in the left-to-right direction shown) relative to the cavity  106 . The second end surface  142  of the flange  136  is positioned outside the countersink  108 . 
     The port  30  is inserted into the passage  126  of the grommet  120  such that the port engages the inner surface  124  of the sidewall  122  and the housing  22  abuts the second end surface  142  of the flange  136 . The sidewall  122  therefore becomes sandwiched between the port  30  the housing  82 . The flange  136  becomes sandwiched between the housings  22  and the end surface  110 . This can result in compression/extrusion of the sidewall  122  and the flange  136 . 
     At the same time, the collar  40  extends over and around the flange  136 . More specifically, the inner surface  44  of the collar extends completely around, e.g., encircles, the outer surface  138  of the flange  136 . The inner surface  44  can be radially spaced from the outer surface  138 . The tapered shape of the end surface  142  of the flange reduces the force needed to compress the flange  136  during insertion of the port  30  into the cavity  106 . 
     The grommet  120  helps to provide a fluid-tight seal between the housings  22 ,  82 . More specifically, the compressed sidewall  122  provides a first sealing interface between the port  30  and the housing  82  in both the axial and circumferential directions. The flange  136  abuts both housings  22 ,  82  to provide a second sealing interface between the housing  22  and the housing  82 . The tapered second end surface  142  advantageously helps to better seal the flange  136  with the housing  22  and collar  40 . 
     The collar  40  can be in close proximity with the housing  82  sufficient to allow for some relative movement between the housings  22 ,  82 , which is damped by the flange  136 . The axial gap between the collar  40  and housing  82 , however, is minimized to help prevent dirt and water from contacting the grommet  120  and/or entering the connection  10 . It will be appreciated that the grommet  120  can be preassembled on the port  30  before inserting the port into the cavity  106 . In this manner, the countersink  108  acts as an axial stop for the flange  136  during insertion of the port  30  into the cavity  106 . 
     The collar  40  can also bottom out on the housing  82  during assembly to help prevent the port  30  from being inserted too far into the cavity  106  and/or damaging the grommet  120 . In particular, inserting the port  30  into a grommet  120  already positioned in the cavity  106  could cause undesirable lengthening of the grommet due to sliding/frictional interface between the port  30  and the inner surface  124 . 
     Brake fluid can flow through the central passage  34 , through the cavity  106 , and ultimately to the passage  84  of the master cylinder assembly  80 . Brake fluid can also return to the reservoir  20  through one of the ports  30 . During the filling process and the leak testing the fluid within the reservoir  20 , the master cylinder assembly  80  and the connection is under high pressure. While the vehicle is moving the reservoir  20  and master cylinder assembly  80  undergo high vibrations. 
     With this in mind, the collar  40  acts to maintain the grommet  120  in a fixed and centered position within the cavity  106 . The collar  40  also advantageously helps to prevent or mitigate vibration by acting as a damping member. To this end, the collar  40  and/or countersink  108  help to mitigate relative movement between the housings  22 ,  82  by interacting with the grommet  120 . 
     When the housing  22  moves towards the housing  82 , flange  136  is compressed between the surfaces  110 . This can cause the flange  136  to extrude radially outward in the manner indicated generally at A. The collar  40 , however, limits this radial expansion/extrusion and cooperates with the outer surface  138  to provide an additional sealing interface between the grommet  120  and housing  22 . Consequently, the collar  40  and countersink  108  advantageously help maintain the grommet  120  centered along the centerline  32  while simultaneously allowing for controlled expansion of the flange  136  during filling and leak testing operations. 
     The collar  40  is also advantageous in that helps accommodate the flange  136  and thereby reduces the depth of the countersink  108  needed to retain the flange. Along those lines, it will be appreciated that the countersink  108  in the housing  80  can be omitted and the axial length of the collar  40  increased to fully accommodate the flange  136 . In other words, the axial length of the inner surface  44  of the collar  40  can be increased to approximate or exceed the axial length of the outer surface  138  of the flange  136  (not shown). Such a modification helps to save space in the housing  80 . 
     In another example shown in  FIG.  3   , a bore  150  extends transversely from the cavity  106  and is in fluid communication with the passage  84  in the master cylinder assembly  80 . When the port  30  and grommet  120  are inserted into the cavity  106 , the axial extent of the sidewall  122  of the grommet is spaced from the bore  150 . In other words, the fully inserted port  30  and grommet  120  do not block the bore  150  or hinder flow therethrough. Additionally, the grommet  120  is prevented from becoming damaged due to pushing the grommet along edges of the bore  150 . Preventing this blockage is due in part to the collar  40  being configured to abut the housing  82  before the grommet  120  bottoms out in the cavity  106 . Another reason is that the collar  40  allows the depth of the countersink  108  to be reduced and thereby allows the port  30  and grommet  120  to extend a lesser depth into the cavity than if the collar were not present. 
     What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.