Patent Publication Number: US-2022235817-A1

Title: Controlled torque bushing with shouldered two-piece inner sleeve

Description:
FIELD 
     The present disclosure relates to bushing assemblies and more particularly to elastomeric bushing assemblies for securing components of a vehicle suspension system. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Elastomeric bushing assemblies have been used in vehicles, particularly in suspension systems that are disposed between a body of the vehicle and a chassis. As the vehicle travels, the body of the vehicle moves relative to the chassis. The relative movement between the body of the vehicle and the chassis is accommodated by various resilient devices of the suspension system disposed therebetween. The flexing of the resilient device may cause a pivoting motion of the resilient devices relative to the components of the body of the vehicle. The elastomeric bushing assemblies are used to connect the resilient devices to the components of the body of the vehicle to facilitate the pivotal motion of the resilient devices relative to the component of the body of the vehicle, thereby absorbing shock applied to the body of the vehicle. 
     An elastomeric bushing assembly typically includes an inner metal sleeve, a bearing, an elastomer layer, and an outer metal housing arranged in this order from inside to outside in the radial direction. The bearing is mounted around the inner metal sleeve and the axial movement of the bearing relative to the inner metal housing is restrained. In one known design, the inner metal sleeve includes a raised barrel section at one longitudinal end of the inner metal sleeve. After the bearing is mounted around the inner metal sleeve from the other longitudinal end, a retaining ferrule or a retaining ring is affixed to the other longitudinal end such that the bearing is disposed around the inner metal sleeve and between the raised barrel and the retaining ferrule/ring. The axial movement of the bearing is limited by the raised barrel section and the retaining ferrule/ring at longitudinal ends of the inner metal housing. Other known designs include a straight inner metal sleeve without raised barrels and retaining rings on both ends. Assembling a typical elastomeric bushing having these structures is time-consuming and complicated due to affixing the retaining ferrule/ring after the bearing is mounted. 
     These issues related to the assembly of elastomeric bushings, among other issues related to bushings for use in vehicle suspensions, are addressed by the present disclosure. 
     SUMMARY 
     This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features. 
     In one form, a bushing assembly is provided, which includes an inner sleeve, a bearing, an elastomeric bushing, and an outer sleeve. The inner sleeve includes two pieces. Each of the two pieces includes a distal end portion and a proximal end portion. Each of the proximal end portions includes an external shoulder having an outer radial face and an inner axial face. The bearing is rotationally mounted around the inner sleeve and captured between each of the inner axial faces of the external shoulders. The elastomeric bushing is disposed around the bearing and abutting the outer radial faces of the external shoulders. The outer sleeve is disposed around the elastomeric bushing and extends at least partially over the external shoulders. 
     In other features, which may be implemented individually or in any combination, the elastomeric bushing abuts the inner axial faces of the external shoulders and includes beads proximate the inner axial faces of the external shoulders and/or the outer radial faces of the external shoulders. Each of the two pieces of the inner sleeve may be symmetrical or asymmetrical and may include a locking feature for securing the two pieces together. One of the two pieces of the inner sleeve includes an axial tab at its distal end portion and the other piece of the inner sleeve includes an axial recess at its distal end portion. The axial tab is press fit into the axial recess to form the locking feature. The external shoulders each define a width, wherein at least one of the outer diameters and the widths of the external shoulders are sized to radially and/or conically tune the elastomeric bushing. 
     In another form, a bushing assembly is provided, which includes an inner sleeve, a bearing, an elastomeric bushing, and an outer sleeve. The inner sleeve consists of two pieces. Each of the two pieces includes a distal end portion and a proximal end portion. Each of the proximal end portions includes an external shoulder having an outer radial face and an inner axial face. The bearing is rotationally mounted around the inner sleeve and captured between each of the inner axial faces of the external shoulders. The elastomeric bushing is disposed around the bearing and abuts the outer radial faces and the inner axial faces of the external shoulders. The outer sleeve is disposed around the elastomeric bushing and extends at least partially over the external shoulders. 
     In still another form, a bushing assembly is provided, which includes an inner sleeve, a bearing, an elastomeric bushing, and an outer sleeve. The inner sleeve includes two pieces. Each of the two pieces includes a distal end portion and a proximal end portion. Each of the proximal end portions includes an external shoulder having an outer radial face and an inner axial face. The bearing is rotationally mounted around the inner sleeve and captured between each of the inner axial faces of the external shoulders. The elastomeric bushing is disposed around the bearing and abuts the outer radial faces and the inner axial faces of the external shoulders. The outer sleeve is disposed around the elastomeric bushing and extending at least partially over the external shoulders. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a bushing assembly constructed in accordance with the teachings of the present disclosure; 
         FIG. 2  is an exploded view of the bushing assembly of  FIG. 1 ; 
         FIG. 3  is an end view of the bushing assembly of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of the bushing assembly, taken along line A-A of  FIG. 3 ; and 
         FIG. 5  is a perspective view of one piece of a two piece inner sleeve of the bushing assembly of  FIG. 1 . 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     Referring to  FIGS. 1 to 4 , a bushing assembly  10  constructed in accordance with the teachings of the present disclosure includes an inner sleeve  12  having a two-piece structure, a bearing  14  rotationally mounted around the inner sleeve  12 , an elastomeric bushing  16  disposed around the bearing  14 , and an outer sleeve  18  disposed around the elastomeric bushing  16 . The inner sleeve  12 , the bearing  14 , the elastomeric bushing  16 , and the outer sleeve  18  are coaxially arranged around a central axis X of the bushing assembly  10 . The inner sleeve  12  defines a central bore  20 . A first component (not shown), such as a resilient device of a suspension system, may be connected to a second component (not shown), such as a component of a body of a vehicle by the bushing assembly  10 . (Such a suspension system and components are illustrated in greater detail in U.S. Pat. No. 10,508,701 titled “Vehicle Suspension Bushing Assembly and Method of Assembling the Same,” which is commonly owned with the present application and the contents of which are incorporated herein by reference in their entirety). By inserting a fastener (not shown) of the first component into the central bore  20  of the inner sleeve  12  and by mounting the second component around the outer sleeve  18 , the first component is connected to the second component. The bearing  14  of the bushing assembly  10  allows the first component to have a pivoting motion relative to the second component. The elastomeric bushing  16  of the bushing assembly  10  allows a limited translational movement between the first and second components. 
     The inner sleeve  12  includes two pieces  22 , each having an inner end portion  24  (i.e., a distal end portion) and an outer end portion  26  (i.e., a proximal end portion) opposing the inner end portion  24  along the central axis X. The inner end portions  24  of the pieces  22  may be provided with one or more locking feature(s)  30  that connects the two pieces  22  together, one form of which is described in greater detail below. 
     Referring more specifically to  FIGS. 4 and 5 , as an example, the locking feature  30  may include a pair of locking tabs  32  and a pair of axial recesses  34 , which may be axial grooves, for receiving the corresponding locking tabs  32  therein. In this form, the locking tabs  32  and the axial recesses  34  extend in an axial direction as shown. The locking tabs  32  protrude from an end surface  33  of the pieces  22 . The axial recesses  34  are recessed from the end surface  33  of the pieces  22 . In one form, each of the pieces  22  is provided with one of the locking tabs  32  and one of the axial recesses  34 . In another form, the pair of locking tabs  32  may be provided at the same piece  22 , while the pair of the axial recesses  34  may be provided at another adjacent piece  22 . Any number and/or any form of the locking feature  30  that can connect the two half pieces  22  together, at least temporarily until the bushing assembly  10  is finally formed, may be used without departing from the scope of the present disclosure. 
     The locking feature  30  is optional and is used to provide a press-fit connection between the two pieces  22  so that the pieces  22  cannot be separated or fall out of the bushing assembly  10  during shipping and handling of the bushing assembly  10 . When the bushing assembly  10  is mounted around a component of a vehicle by inserting a fastener of the component into the central bore  20  of the inner sleeve  12 , the bushing assembly  10  is secured to the fastener of the component by other means and thus the two pieces  22  of the inner sleeve  12  cannot be separated or move in an axial direction of the fastener whether the locking feature  30  is used or not. 
     Referring to  FIG. 5 , each of the pieces  22  of the inner sleeve  12  includes an external shoulder  40  at the outer end portion  26 . The external shoulder  40  extends radially from a cylindrical outer surface  42  of the half piece  22  such that a step is defined between the cylindrical outer surface  42  and the external shoulder  40 . The external shoulder  40  may be an annular shoulder in one form and defines an inner axial face  44  extending in a radial direction and vertical to the cylindrical outer surface  42  and an outer radial face  46  extending in an axial direction and parallel to the cylindrical outer surface  42 . A positional feature  48 , which may be a cutout in one form, may be provided on the external shoulder  40  to provide an indication of the position and/or orientation of the locking feature  30 . 
     Referring back to  FIG. 4 , when the two pieces  22  are placed in position and are optionally affixed together by the locking features  30 , the cylindrical outer surfaces  42  and the inner axial faces  44  of the external shoulder  40  define a recessed area  50  for receiving the bearing  14  therein. The bearing  14  is rotationally mounted around the inner sleeve  12  and captured between the inner axial faces  44  of the external shoulders  40 . The length of the recessed area  50  is approximately the length of the bearing  14 . When the bearing  14  is assembled around the inner sleeve  12 , the end faces of the bearing  14  abut the inner axial faces  44  of the external shoulders  40 . Therefore, the axial movement of the bearing  14  in the central axis X is restrained by the external shoulders  40  of the pieces  22  of the inner sleeve  12 . 
     The elastomeric bushing  16  is mounted around the bearing  14  and extends at least partially over the external shoulders  40  of the inner sleeve  12  such that the elastomeric bushing  16  contacts the inner axial faces  44  and the outer radial faces  46  of the external shoulders  40 . A part of the elastomeric bushing  16  is disposed in the recessed area  50  defined between the external shoulders  40 . The elastomeric bushing  16  includes annular ridges or beads  52  on an inner surface proximate the inner axial faces  44  of the external shoulders  40  and/or the outer radial faces  46  of the external shoulders  40  to increase the frictional contact and engagement between the inner surface of the elastomeric bushing  16  and the surfaces of the external shoulders  40 . 
     The outer sleeve  18 , which has a tubular/cylindrical shape, is mounted around the elastomeric bushing  16  and extends at least partially over the external shoulders  40 . The outer sleeve  18  and elastomeric bushing  16  as shown extend over a majority of the external shoulders  40  in one form as illustrated herein. However, the overall length of the outer sleeve  18  and/or elastomeric bushing  16  could be shorter such that only a portion of the outer sleeve  18  and/or elastomeric bushing  16  extends over the external shoulders  40 . In yet another form not shown, the outer sleeve  18  and the elastomeric bushing  16  may extend up to, or near, and not extend over the external shoulders  40 . These and other variations of the lengths of the outer sleeve  18  and elastomeric bushing  16  should be construed as being within the scope of the present disclosure. 
     The external shoulders  40  of the inner sleeve  12  may be sized such that a space between the external shoulder  40  and the inner surface of the outer sleeve  18  is limited and such that the external shoulders  40  can also be used as a radial and/or conical displacement limiter for the elastomer bushing  16 . For example, the external shoulders each define a width. At least one of the outer diameters and the widths of the external shoulders  40  are sized to radially and/or conically tune the elastomeric bushing. 
     In the present disclosure, the two-piece structure of the inner sleeve  12  allows the bearing  14  to be easily mounted around the inner sleeve  12  and between external shoulders  40 , by inserting the half pieces  22  of the inner sleeve  12  into the bearing  14  from opposite ends of the bearing  14 . When the pieces  22  are fully assembled, the axial movement of the bearing  14  is simultaneously restrained by the external shoulders  40 . In other words, in order to properly mount the bearing  14  around the inner sleeve  12 , the bushing assembly  10  of the present disclosure requires only one step of inserting the half pieces  22  into the bearing  14  from opposite ends while simultaneously restraining the axial movement of the bearing  14 , as opposed to a typical bushing assembly, which requires a step of mounting a bearing around the inner sleeve and a step of affixing a retaining ferrule/ring at one or both ends of the inner sleeve to restrain axial movement of the bearing. Therefore, the bushing assembly  10  of the present application can save assembling time and the associated manufacturing costs. 
     In addition, the two-piece structure of the inner sleeve  12  allows one or more lip seals to be provided in combination with a labyrinth seal to be provided adjacent to the external shoulders  40  of the inner sleeve  12  for improved corrosion protection. The lip seal(s) may be rubber compression seal(s) on the inner axial faces  44  and/or the outer radial faces  46  of the external shoulders  40  to seal out contaminants. The design also provides a non-direct path from the outside to the bearing surface providing the additional labyrinth effect. 
     Further, this design also allows the two pieces  22  to be symmetrical so that the inner sleeve  12  may include two identical pieces to help reduce tooling costs and increase volumes. It is understood that the two pieces  22  may be made to have nonsymmetrical structures if a directional feature  48  should be added to only one of the half pieces  22 . 
     Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability. 
     As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” 
     The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.