Abstract:
A vibration-damping bushing assembly wherein a vibration-damping bushing is axially press-fit into a rigid cylindrical retainer of a companion member to be assembled therewith at an outer circumferential surface of an outer cylindrical member of the bushing. A rigid spacer ring band, of annular shape, is mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member. A flange of the outer cylindrical member and an end surface of the cylindrical retainer are brought into axial contact through the spacer ring band, and the spacer ring band is partially provided with at least one protrusion protruding on an inner circumferential surface so as to be fitted and fixed to the outer cylindrical member at the protrusion. A vibration-damping bushing and a rigid spacer ring band for the assembly are also disclosed.

Description:
INCORPORATED BY REFERENCE  
       [0001]     The disclosure of Japanese Patent Application No. 2004-338062 filed on Nov. 22, 2004 including the specification, drawings and abstract is incorporated herein by reference in its entirety.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a vibration-damping bushing comprising a rubber elastic body interposed between a rigid outer cylindrical member and inner cylindrical member, and a vibration-damping bushing assembly for fitting, mounting, and fixing the vibration-damping bushing to a rigid cylindrical retainer of a companion member.  
         [0004]     2. Description of the Related Art  
         [0005]     Conventionally, vibration-damping bushings with a rubber elastic body interposed between a rigid, outer cylindrical member having a flange in the radial outward direction at the axial end and a rigid inner cylindrical member disposed inside have been widely used as suspension bushings and the like elastically joining vehicle bodies and suspension arms. This type of vibration-damping bushing is ordinarily axially fitted to be mounted and fixed to a rigid cylindrical retainer of a companion member on the circumferential surface of an outer cylindrical member.  
         [0006]     This type of vibration-damping bushing was specially made according to the type of vehicle or to the type or shape of the companion member, and was then mounted and fixed to the companion member. For example, in the case of suspension bushings disposed in coupling components between vehicle bodies and suspension arms, special vibration-damping bushings are produced according to the different types and shapes of the suspension arms serving as the companion member. However, the costs for such vibration-damping bushings are inevitably high.  
         [0007]     One major to reduce the costs of such vibration-damping bushings would be to devise a single type of vibration-damping that could be shared, that is, one that could be used universally, regardless of the type or shape of companion members such as suspension arms. However, attempts to do so, have resulted in an axial gap between the end surface of the cylindrical retainer and the flange at the end of the outer cylindrical member, as the axial mounting positions of the vibration-damping bushing and cylindrical retainer are variable depending on the type and shape of the companion member.  
         [0008]     When such a gap is produced between the end surface of the cylindrical retainer and the outer cylindrical member, a resulting problem is that the vibration-damping bushing is axially displaced from the proper mounting position relative to the cylindrical retainer when axial force is exerted on the vibration-damping bushing by input force on the vehicle. Particularly when the cylindrical retainer of the companion member is formed by a pressing process such as burring, the axial length of the cylindrical retainer cannot be lengthened, resulting in a shorter axial fitting length between the cylindrical retainer and the vibration-damping bushing, specifically, the outer cylindrical member, and thus in less frictional contact area. This results in weaker retention force on the vibration-damping bushing by the cylindrical retainer, and greater susceptibility to axial displacement of the vibration-damping bushing. This is illustrated in detail by  FIG. 8 .  
         [0009]     In  FIG. 8, 200  is the vibration-damping bushing, which comprises an outer cylindrical member (rigid outer cylindrical member)  202  and inner cylindrical member (rigid inner cylindrical member)  204 , with a rubber elastic body  206  interposed between the outer cylindrical member  202  and inner cylindrical member  204  to be integrally bonded by vulcanization to join the outer cylindrical member  202  and inner cylindrical member  204  in the radial direction. The outer cylindrical member  202  has a radially outward-facing annular flange  208  at the axial  
         [0010]      210  is a suspension arm serving as the companion member, the end of which is provided with a cylindrical retainer  212  formed by a pressing process such as burring. The cylindrical retainer  212  has an mounting hole  214  on the inside, where the vibration-damping bushing  200  is axially fitted at the outer circumferential surface of the outer cylindrical member  202  to be mounted and fixed.  
         [0011]      FIG. 8  illustrates the vibration-damping bushing  200  and suspension arm  210 , specifically, the cylindrical retainer  212 , mounted in the proper mounting position. An axial gap x is produced between the end surface of the cylindrical retainer  212  and the flange  208  of the outer cylindrical member  202  of the vibration-damping bushing  200  in this state. When such a gap x occurs between the end surface of the cylindrical retainer  212  and the flange  208 , a resulting problem is that the vibration-damping bushing  200  tends to become axially displaced relative to the cylindrical retainer  212 , because of the relatively weak retaining force by the cylindrical retainer  212  formed by a pressing process, whenever axial force is exerted on the vibration-damping bushing  200  by force on the vehicle.  
         [0012]     As a way to address this problem, a rigid spacer ring band  216  made of metal or the like, which as illustrated in  FIG. 9A  is in the form of a circumferentially continuous ring and is in the form of a band thick enough as a whole to correspond to the gap x, is mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member  202 , and the spacer ring band  216  is interposed between the flange  208  and the cylindrical retainer  212  end surface, that is, the vibration-damping bushing  200  is assembled therewith at the cylindrical retainer  212 , with the flange  208  and cylindrical retainer  212  end surface brought into contact through the spacer ring band  216 . As this allows the axial gap between the flange  208  and the cylindrical retainer  210  end surface to be filled up by the spacer ring  216 , thereby preventing the vibration-damping bushing  200  from becoming displaced relative to the cylindrical retainer  212  when axial force is exerted on the vibration-damping bushing  200 .  
         [0013]     JP-U-60-75734 describes a slip-proof rubber bushing in which the outer cylindrical member is formed with hard plastic, and the cylindrical retainer of the companion member is provided with a protrusion on the inner circumference to allow the protrusion to bite into the outer cylindrical member, thus preventing the rubber bushing from slipping in the axial direction, but unlike the present invention, this does not involve the use of a spacer ring band to mount a vibration-damping bushing.  
         [0014]     JP-A-9-68246 below discloses an invention regarding an elastic bushing, in which the flange of the outer cylindrical member of the vibration-damping bushing has different levels in the axial direction, so that the axial gap between the vibration-damping bushing and the bracket on the companion side is filled in based on the difference in levels, but unlike the present invention, this does not involve the use of a spacer ring band.  
       SUMMARY OF THE INVENTION  
       [0015]     It is therefore one object of this invention to provide a vibration-damping bushing and a vibration-damping bushing assembly which can be used as a shared vibration-damping bushing regardless of differences in the type of vehicle or in the type or shape of companion members, and which in such cases allows enough pressure-based fixing force to be achieved without axial displacement of the vibration-damping bushing relative to the cylindrical retainer of the companion member.  
         [0016]     As a way to address this problem, the present inventors has proposed that a rigid spacer ring band  216  made of metal or the like, which as illustrated in  FIG. 9A  is in the form of a circumferentially continuous ring and is in the form of a band thick enough as a whole to correspond to the gap x (see  FIG. 8 ), is mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member  202 , and the spacer ring band  216  is interposed between the flange  208  and the cylindrical retainer  212  end surface, that is, the vibration-damping bushing  200  is assembled therewith at the cylindrical retainer  212 , with the flange  208  and cylindrical retainer  212  end surface brought into contact through the spacer ring band  216 . As this allows the axial gap between the flange  208  and the cylindrical retainer  210  end surface to be filled up by the spacer ring  216 , thereby preventing the vibration-damping bushing  200  from becoming displaced relative to the cylindrical retainer  212  when axial force is exerted on the vibration-damping bushing  200 .  
         [0017]     The spacer ring band  216  is mounted by pressure onto the outer cylindrical member  202  before the vibration-damping bushing  200  is assembled therewith at the cylindrical retainer  212 , but this has been found to result in the following problems. That is, when the entire internal circumferential surface of the spacer ring band  216  is tightly fixed (mounted) by axial pressure relative to the outer circumferential surface of the outer cylindrical member  216 , the outside diameter of the outer cylindrical member  202  is constricted by the pressure at that time, and when the vibration-damping bushing  200  is then fitted to the cylindrical retainer  212 , there is a change (a reduction) in the fixing force by means of pressure due to the change in the dimensions of the outer cylindrical member  202 , preventing the desired fixing force from being obtained.  
         [0018]     As a way to address this problem, the outer cylindrical member  202  has a stepped configuration comprising a large diameter component  202 A and a small diameter component  202 B, as illustrated in  FIG. 9B , the spacer ring band  216  is fixed by pressure to the large diameter component  202 A, and the small diameter component  202 B of the outer cylindrical member  202  is fitted to and mounted in the cylindrical retainer  212 . However, in this case, the pressure of the spacer ring band  216  on the large diameter component  202 A deforms (constricts) the small diameter component  202 B, making this an unsuitable way to address the problem.  
         [0019]     In view of the above, the present inventors further improve the invention, and the above and/or optional objects of this invention may be attained according to at least one of the following modes of the invention. The following modes and/or elements employed in each mode of the invention may be adopted at any possible optional combinations. It is to be understood that the principle of the invention is not limited to these modes of the invention and combinations of the technical features, but may otherwise be recognized based on the teachings of the present invention disclosed in the entire specification and drawings or that may be recognized by those skilled in the art in the light of the present disclosure in its entirety.  
         [0020]     A first mode of the invention provides a vibration-damping bushing assembly wherein a vibration-damping bushing including: a rigid outer cylindrical member having a radially outward-facing flange at one axial end; a rigid inner cylindrical member disposed inside the outer cylindrical member; and a rubber elastic body interposed between and elastically connecting the outer and inner cylindrical members, and wherein the vibration-damping bushing is axially press-fit into a rigid cylindrical retainer of a companion member to be assembled therewith at an outer circumferential surface of the outer cylindrical member, characterized in that a rigid spacer ring band of annular shape is mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member, the flange of the outer cylindrical member and an end surface of the cylindrical retainer being brought into axial contact through the spacer ring band, and the spacer ring band is partially provided with at least one protrusion protruding on an inner circumferential surface so as to be fitted and fixed to the outer cylindrical member at the protrusion.  
         [0021]     A second mode of the invention provides a vibration-damping bushing assembly according to the first mode, wherein the at least one protrusion comprises a plurality of protrusions that are provided in a plurality of locations at intervals in a circumferential direction.  
         [0022]     A third mode of the invention provides a vibration-damping bushing assembly according to the second mode, wherein the plurality of protrusions are provided in one or a plurality of locations at intervals in an axial direction.  
         [0023]     A fourth mode of the invention provides a vibration-damping bushing assembly according to the second mode, wherein a portion of the spacer ring band located between the adjacent protrusions are in a suspended state not in contact with the outer cylindrical member so that a gap is produced between the band and the outer cylindrical member, and the radial deformability is greater due to the gap when pressure is exerted on the portions between the protrusions.  
         [0024]     A fifth mode of the invention provides a vibration-damping bushing assembly according to any one of the first through fourth modes, wherein the cylindrical retainer is made of metal and is formed by a pressing process.  
         [0025]     A sixth mode of the invention provides a vibration-damping bushing comprising: a rigid outer cylindrical member having a radially outward-facing flange at one axial end; a rigid inner cylindrical member disposed inside the outer cylindrical member; and a rubber elastic body interposed between and elastically connecting the outer and inner cylindrical members, and wherein the vibration-damping bushing is adapted to be axially press-fit into a rigid cylindrical retainer of a companion member to be assembled therewith at an outer circumferential surface of the outer cylindrical member; and a rigid spacer ring band of annular shape adapted to be mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member, so as to be interposed between the flange of the outer cylindrical member and an end surface of the cylindrical retainer, the spacer ring band being partially provided with at least one protrusion protruding on an inner circumferential surface so as to be fitted and fixed to the outer cylindrical member at the protrusion.  
         [0026]     A seventh mode of the invention provides A rigid spacer ring band for use in a vibration damping bushing assembly wherein a vibration-damping bushing including: a rigid outer cylindrical member having a radially outward-facing flange at one axial end; a rigid inner cylindrical member disposed inside the outer cylindrical member; and a rubber elastic body interposed between and elastically connecting the outer and inner cylindrical members, and wherein the vibration-damping bushing is adapted to be axially press-fit into a rigid cylindrical retainer of a companion member to be assembled therewith at an outer circumferential surface of the outer cylindrical member, characterized in that: said rigid spacer ring of annular shape is in the form of a band as a whole, and is adapted to be mounted while externally fitted by means of axial pressure on the circumferential surface of the outer cylindrical member so that the flange of the outer cylindrical member and an end surface of the cylindrical retainer being brought into axial contact through the spacer ring band; and the spacer ring band being partially provided with at least one protrusion protruding on an inner circumferential surface so as to be fitted and fixed to the outer cylindrical member at the protrusion.  
         [0027]     As noted above, the present invention is one in which the spacer ring band is partially provided with protrusions protruding on the inner circumferential side. According to the invention, less pressure force is needed than when the spacer ring band is fitted and tightly fixed along the entire inner circumferential surface to the outer circumferential surface of the outer cylindrical member of the vibration-damping bushing, and there is less radially constricting force exerted on the outer cylindrical member, resulting in substantially no radially constricting deformation of the outer cylindrical member, thereby ensuring the set tightening, that is, fixing force, when the vibration-damping bushing is subsequently fitted to the cylindrical retainer of the companion member.  
         [0028]     While thus mounted and fixed, the spacer ring band is interposed between the flange of the outer cylindrical member and the end surface of the cylindrical retainer to allow the spacer ring band to fill up the axial gap between flange and the end surface of the cylindrical retainer, thus ensuring that the vibration-damping bushing is prevented from becoming displaced relative to the cylindrical retainer when axial force is imposed on the vibration-damping bushing by force on the vehicle.  
         [0029]     In the present invention, the protrusions can be provided in a plurality of locations at intervals in the circumferential direction (Second mode). This can bring about radial deformability in the portions (circumferential portions) of the spacer ring band between the protrusions, and the dimensional differences occurring when pressure is exerted on the spacer ring band can be effectively absorbed by the radial deformation of the portions between the protrusions. That is, despite irregularities in the outside diameter of the outer cylindrical member and the inside diameter of the spacer ring band, the desired fixing force by pressure on the spacer ring band can be ensured, and substantial constricting force from the spacer ring band on the outer cylindrical member can be prevented.  
         [0030]     In this case, the protrusions can be provided in a continuous linear formation in the axial direction, but protrusions can also be provided in one location or at intervals in a plurality of locations in the axial direction (Third mode). It is more desirable to provide one in one location in the axial direction, as this will allow enough pressure to be obtained to fix the spacer ring band while also minimizing constricting force from the spacer ring band onto the outer cylindrical member.  
         [0031]     The protrusions are preferably provided in three locations at 120° intervals in the circumferential direction. This will allow the spacer ring band to be fitted and fixed to the outer cylindrical member with uniform force at the protrusions.  
         [0032]     In the fourth mode, the portions of the spacer ring band in the circumferential direction between the protrusions are in a suspended state not in contact with the outer cylindrical member, so that a gap is produced between the band and the outer cylindrical member, and the radial deformability between the protrusions is greater due to the gap. Thus, the above effects are more effectively brought about based on the greater deformability.  
         [0033]     The present invention is particularly effective in applications where the cylindrical retainer of the companion member is made of metal and is formed by a pressing process (Fifth mode). A vibration damping bushing as well as a rigid spacer ring band, which are suitable for executing the aforementioned assembly according to the present invention, are also provided (Sixth mode and Seventh mode). 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]     The forgoing and/or other objects features and advantages of the invention will become more apparent from the following description of a preferred embodiment with reference to the accompanying drawings in which like reference numerals designate like elements and wherein:  
         [0035]      FIG. 1  is partial cross sectional plane view of a vibration damping bushing assembly with a suspension arm serving as a companion member;  
         [0036]      FIG. 2  is a fragmentary view showing a principle part of  FIG. 1 ;  
         [0037]      FIG. 3  is a cross sectional view taken along line  3 - 3  of  FIG. 2 ;  
         [0038]      FIG. 4  is a perspective view showing a vibration damping bushing of the assembly of  FIG. 1 ;  
         [0039]      FIGS. 5A, 5B  and  5 C show one form of a spacer ring band in perspective, in transverse cross section and in axial cross section, respectively;  
         [0040]      FIGS. 6A and 6B  are views suitable for explaining a method of assembly of the bushing;  
         [0041]      FIGS. 7A, 7B  and  7 C show another form of the spacer ring band in perspective, in transverse cross section and in axial cross section, respectively;  
         [0042]      FIG. 8  shows a conventional vibration damping bushing assembly of construction;  
         [0043]      FIGS. 9A and 9B  show trial measures proposed by the inventors for solving a problem involved in the conventional assembly in  FIG. 8 ;  
         [0044]      FIGS. 10A and 10B  show another form of the spacer ring band in perspective, in transverse cross section and in axial cross section, respectively;  
         [0045]      FIGS. 11A and 11B  show another form of the spacer ring band in perspective, in transverse cross section and in axial cross section, respectively; and  
         [0046]      FIGS. 12A and 12B  show another form of the spacer ring band in perspective, in transverse cross section and in axial cross section, respectively. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0047]     Preferred embodiments of the invention in suspension bushing assemblies will be described in greater detail with reference to the drawings.  FIG. 1  shows a suspension arm  10 , referred to as a so-called A arm, serving as a companion member, for linking a vehicle body and wheel. In  FIG. 1 , a bottom end of the suspension arm  10  is joined to a wheel side, and a top end is joined to a shaft  12  fixed to the vehicle body. A vibration-damping bushing  14  is disposed in the part connecting the suspension arm  10  and shaft  12 . The specific assembly is illustrated in  FIG. 2 .  
         [0048]     As illustrated in  FIG. 2 , the vibration-damping bushing  14  has a metallic outer cylindrical member (rigid outer cylindrical member)  16  and a metallic inner cylindrical member (rigid inner cylindrical member)  18  disposed on the inside, with a cylindrical rubber elastic body  20  interposed between the outer cylindrical member  16  and inner cylindrical member  18  to elastically join them together.  
         [0049]     A through shaft  22  of the shaft  12  is inserted into the inner cylindrical member  18  in the vibration-damping bushing  14 . The tip of the through shaft  22  is in the form of male threading  24 , to which a nut  26  is screwed, so that by means of the tightening force, both end surfaces of the inner cylindrical member  18  are forcibly sandwiched in the axial direction between a metal plate  28  and a stepped portion  30  of the shaft  12 .  
         [0050]     The outer cylindrical member  16  is formed of a large diameter component  16 A and a small diameter component  16 B, with a radially outward-facing flange  32  formed in the shape of a ring at the axial end (left end in the figure). The rubber elastic body  20  includes a flange  33  integrally formed in a shape corresponding to the flange  32  on the rubber elastic body  20 . The flange  33  serves as an axial rubber stopper.  
         [0051]     The suspension arm  10  illustrated in  FIG. 1  is formed by bending a metal sheet, and has a cylindrical retainer  34  at the end on the vehicle body side. The cylindrical retainer  34  has a mounting hole  36  on the inside, to which the vibration-damping bushing  14  is axially fitted to be mounted and fixed at the outer circumferential surface of the outer cylindrical member  16 . The cylindrical retainer  34  is formed by a pressing process, in this case, a burring process, where  38  is a cylindrical portion serving as the main part, and  40  is a panel shaped component serving as a flange for the cylindrical portion  38 .  
         [0052]     In this embodiment, as illustrated in  FIG. 2 , the metal spacer ring band  42  is interposed between the end surface of the cylindrical retainer  34  and the flange  32  of the outer cylindrical member  16 , the flange  32  and the end surface of the cylindrical retainer  34  coming into axial contact through the spacer ring band  42 . As illustrated in  FIGS. 3, 4  and  5 , the spacer ring band  42  is in the form of a circumferentially continuous round ring, and is also band-shaped with a certain width in the axial direction.  
         [0053]     Protrusions  44  formed by forming recesses inwardly from the outer circumferential surface portions of the spacer ring band  42 , that is, protrusions  44  protruding on the inner circumference, are provided in three locations (see  FIG. 3 ) in the circumferential direction. Here, the protrusions  44  are provided at locations 120° apart in the circumferential direction. As illustrated in  FIG. 5A , the protrusions  44  are discontinuous in the axial direction, the protrusions  44  being provided in only one axial location.  
         [0054]     As illustrated in  FIGS. 2, 3 , and  4 , the spacer ring band  42  is axially fitted and fixed to the outer circumferential surface of the outer cylindrical member  16  of the vibration-damping bushing  14  only at the protrusions  44 . All of the other portions are in a suspended state not in contact with the outer circumferential surface of the outer cylindrical member  16 , forming a gap S between the band and the outer cylindrical member  16 . As a result, as illustrated in  FIG. 5B , the circumferential portions  42 A of the spacer ring band  42  between the protrusion  44  and  44  have substantial radial deformability.  
         [0055]     In this embodiment, the vibration-damping bushing  14  is mounted on the cylindrical retainer  34  of the suspension arm  10  in the following manner. That is, as illustrated in  FIG. 6A , the spacer ring band  42  is first fitted axially relative to the outer cylindrical member  16  of the vibration-damping bushing  14 , and it is mounted on the outer cylindrical member  16  at a location where the front end (left end) of the spacer ring band  42  in the figure comes into contact with the flange  32  of the outer cylindrical member  16 .  FIG. 6B  illustrates the mounted state.  
         [0056]     When the spacer ring band  42  is fitted to the outer cylindrical member  16 , the spacer ring band  42  comes into frictional contact with the outer circumferential surface of the outer cylindrical member  16  only at the three points where the protrusions  44  are, and the other parts are in a suspended state not in contact with the outer cylindrical member  16 . Thus, the tightening force from the spacer ring band  42  to the outer cylindrical member  16  is limited to the three points of the protrusions  44  in the three locations, with substantially no constricting compressive force exerted on the outer cylindrical member  16 .  
         [0057]     When the spacer ring band  42  is fitted to the outer cylindrical member  16 , despite the dimensional variation in the established differences between the outside diameter of the outer cylindrical member  16  and the inside diameter of the spacer ring band  42 , it is well absorbed by the radial deformation of the portions  42 A between the protrusions  44  and  44 . In other words, as a result of the deformability, no excess constricting force acts on the outer cylindrical member  16  by means of the protrusions  44 , and the spacer ring band  42  is fitted and fixed with enough fixing force to the outer cylindrical member  16  at the protrusions  44 .  
         [0058]     After the spacer ring band  42  has thus been mounted on the outer cylindrical member  16 , the vibration-damping bushing  14  is fitted axially into the mounting hole  36  of the cylindrical retainer  34  of the suspension arm  10  (up to the point where the spacer ring band  42  is in contact with the end surface of the cylindrical retainer  34 ). The vibration-damping bushing  14  is mounted on the cylindrical retainer  34  of the suspension arm  10 .  
         [0059]     In the vibration-damping bushing  14  assembly in the above embodiment, the spacer ring band  42  is fitted and fixed to the outer cylindrical member  16  of the vibration-damping bushing  14  at the three protrusions  44 , so that less pressing force is needed than when the spacer ring band  42  is fitted and fixed along the entire inner circumferential surface to the outer circumferential surface of the outer cylindrical member  16 . There is also less constricting force (compressive force) exerted on the outer cylindrical member  16 , resulting in substantially no radially constricting deformation of the outer cylindrical member  16 , thereby ensuring that the desired set fixing force is obtained when the vibration-damping bushing  14  is subsequently fitted to and mounted on the cylindrical retainer  34  of the suspension arm  10 .  
         [0060]     In addition, because the spacer ring band  42  is interposed between the flange  32  of the outer cylindrical member  16  and the end surface of the cylindrical retainer  34  in the assembly, allowing the axial gap S between the flange  32  and the end surface of the cylindrical retainer  34  to be filled by the spacer ring band  42 , the vibration-damping bushing  14  is prevented from becoming displaced relative to the cylindrical retainer  34  even when force on the vehicle results in axial force on the vibration-damping bushing  14 . Furthermore, since the protrusions  44  are provided in three locates 120° apart in this embodiment, the spacer ring band  42  is fitted and fixed to the outer cylindrical member  16  with uniform force.  
         [0061]     The above embodiments of the inventions were described in detail but are ultimately only examples. For instance, the protrusions  44  of the spacer ring band  42 , as shown in  FIGS. 7A, 7B  and  7 C, may have a form continuously extending over an entire axial length of the spacer ring band  42 . Alternatively, the protrusions  44 , as shown in  FIGS. 10A and 10B , may have a form continuously extending over an entire circumferential length of the spacer ring band  42 .  
         [0062]     In the illustrated embodiment, the protrusions  44  of the spacer ring band  42  are provided in the form of inward projections by means of pressing. Alternatively, the protrusions  44  may be formed by inwardly bending a part of the circumferential surface of the spacer ring band  42 , as shown in  FIGS. 11A and 11B . Furthermore, the protrusions  44  may be formed by inwardly bending or drawing one axial end portion of the spacer ring band  42 , as shown in  FIGS. 12A and 12B . Other possible modification in the form of the protrusion may be employed as long as these are workable to provide the aforementioned effect of the invention.  
         [0063]     While the present invention may be suitably employed in the case of assembling the vibration-damping bushing  14  with respect to the retainer  34  formed by burring or other pressing processes, the invention may similarly be applied to the assembly of bushings with respect to retainers of different constructions. Likewise, the present invention may be suitably applicable to the assembly of bushings with respect to retainers formed on companion members other than suspension arms. It is also to be understood that the present invention may be embodied with various changes, modifications and improvements which may occur to those skilled in the art, without departing from the spirit and scope of the invention.