Patent Publication Number: US-2017355241-A1

Title: Strut mount

Description:
TECHNICAL FIELD 
     The present disclosure relates to a strut mount interposed between a vehicle body and a piston rod of a shock absorber of a suspension. 
     BACKGROUND ART 
     Patent Document 1 discloses a strut mount including an interior member, an exterior member, an elastic member, and an upper member. The interior member is passed through by and fixed to a piston rod. The exterior member includes a cylindrical part surrounding the interior member, and a bottom formed in a ring shape by extending radially inward from the lower end of the cylindrical part. The elastic member is formed in a ring shape between the interior member and the exterior member. The upper member and the bottom of the exterior member sandwich the elastic member. The outer circumferential surface of the elastic member is in contact with the inner circumferential surface of the cylindrical part of the exterior member. When vibrations are applied to the strut mount, the elastic member is elastically deformed to absorb the vibrations. 
     CITATION LIST 
     Patent Document 
     [PATENT DOCUMENT 1] Japanese Unexamined Patent Publication No. 2010-14132 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     According to the Patent Document 1, however, the outer circumferential surface of the elastic member is in contact with the inner circumferential surface of the cylindrical part of the exterior member. When vibrations are applied to the strut mount, the contact between the elastic member and the cylindrical part of the exterior member hinders the elastic deformation of the elastic member. This causes insufficient absorption of the vibrations and transmission of the vibrations to the vehicle body, which allows the occupant(s) of the vehicle to feel uncomfortable. 
     The present disclosure was made in view of the problem. It is an objective of the present disclosure to provide a strut mount, which is interposed between a vehicle body and a piston rod of a shock absorber of a suspension, and allows the occupant(s) of a vehicle to feel comfortable. 
     Solution to the Problem 
     In order to achieve the objective, one of the features of the present disclosure is that an elastic member is positioned not to come into contact with a cylindrical part of an exterior member over its entire axial length and over its entire circumference. 
     Specifically, the present disclosure provides a strut mount interposed between a vehicle body and a piston rod of a shock absorber of a suspension, and having the following features. 
     According to the present disclosure, the strut mount includes an interior member passed through by and fixed to the piston rod; an exterior member including a cylindrical part surrounding the interior member, and a bottom formed in a ring shape by extending radially inward from a lower end of the cylindrical part, an elastic member formed in a ring shape between the interior member and the exterior member, and sandwiched between a part of the vehicle body or an upper member and the bottom of the exterior member; and a positioner radially positioning the elastic member. The elastic member is not in contact with the cylindrical part of the exterior member over its entire axial length and over its entire circumference. 
     With this configuration, the elastic member is radially positioned not to come into contact with the cylindrical part of the exterior member over its entire axial length and over its entire circumference. When vibrations are applied to the strut mount, the contact between the elastic member and the cylindrical part of the exterior member does not hinder elastic deformation of the elastic member. That is, the strut mount effectively absorbs the vibrations, thereby allowing the occupant(s) of the vehicle to feel comfortable. 
     In one preferred aspect, each of a bottom surface of the elastic member and a top surface of the bottom of the exterior member is inclined upward at a constant angle over its entire circumference, as it goes radially inward, and the positioner includes the bottom surface of the elastic member and the top surface of the bottom of the exterior member. 
     With this configuration, the top surface of the bottom of the exterior member comes into contact with the bottom surface of the elastic member over its entire circumference radially from the inside, thereby radially positioning the elastic member. 
     In addition, each of the bottom surface of the elastic member and the top surface of the bottom of the exterior member is inclined at the constant angle over its entire circumference. When the elastic member and the exterior member are assembled, there is thus no need to allow one of the elastic member and the exterior member to rotate with respect to the other so that the bottom surface of the elastic member circumferentially corresponds to the top surface of the bottom of the exterior member. This configuration facilitates the assembly. 
     There is also no need to provide any convex or concave for positioning in the elastic member. This configuration simplifies the structure of a mold for the elastic member. 
     In one preferred aspect, a projection is formed in a ring shape on one of a bottom surface of the elastic member and a top surface of the bottom of the exterior member over its entire circumference, a groove is formed in a ring shape on the other, the projection is to be fitted into the groove, and the positioner includes the projection and the groove. 
     With this configuration, the projection is fitted into the groove over their entire circumferences, thereby radially positioning the elastic member. 
     In addition, each of the projection and the groove is formed in a ring shape over its entire circumference of the associated surface. When the elastic member and the exterior member are assembled, there is thus no need to allow one of the elastic member and the exterior member to rotate with respect to the other so that the bottom surface of the elastic member circumferentially corresponds to the top surface of the bottom of the exterior member. This configuration facilitates the assembly. 
     In one preferred aspect, convexes are circumferentially formed on one of a bottom surface of the elastic member and a top surface of the bottom of the exterior member, concaves are circumferentially formed on the other, the convexes are to be fitted into the concaves, and the positioner includes the convexes and the concaves. 
     With this configuration, the convexes are fitted into the concaves, thereby radially positioning the elastic member. 
     In addition, the convexes and the concaves are formed circumferentially. This configuration limits the circumferential rotation of the elastic member with respect to the exterior member, thereby reducing wear of the elastic member. 
     In one preferred aspect, the elastic member is made of foamed urethane resin. 
     With this configuration, the elastic member is made of foamed urethane resin. This reduces the dynamic/static ratio, while improving damping properties. 
     Advantages of the Invention 
     As described above, the present disclosure effectively absorbs vibrations, thereby allowing the occupant(s) of the vehicle to feel comfortable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a strut mount according to an embodiment 1, before fixture of an upper member. 
         FIG. 2  is a top view of the strut mount according to the embodiment 1. 
         FIG. 3  is a cross-sectional view taken along the line A-A of  FIG. 2 . 
         FIG. 4  illustrates an embodiment 2 and corresponds to  FIG. 1 . 
         FIG. 5  illustrates the embodiment 2 and corresponds to  FIG. 3 . 
         FIG. 6  illustrates an embodiment 3 and corresponds to  FIG. 1 . 
         FIG. 7  illustrates the embodiment 3 and corresponds to  FIG. 3 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments will now be described with reference to the drawings. 
     Embodiment 1 
       FIGS. 1 to 3  illustrate a strut mount  1  according to an embodiment 1 of the present disclosure. This strut mount  1  is interposed between a body panel  2  of a vehicle and a piston rod  3  of a shock absorber of a suspension to reduce transmission of vibrations from a road surface to the vehicle body panel  2 . 
     The strut mount  1  includes an interior member  10 , an exterior member  11 , an elastic member  12 , and an upper member  13 . The interior member  10  is a metal disk fixed to the upper end of the piston rod  3 . The exterior member  11  is made of metal and surrounds the interior member  10 . The elastic member  12  is formed in a ring shape between the interior member  10  and the exterior member  11 . The upper member  13  is attached to the exterior member  11 . 
     A circular insertion hole  10   a  is formed at the center of the interior member  10 . The piston rod  3  is inserted through and fixed to the insertion hole  10   a.    
     The exterior member  11  includes a cylindrical part  11   a , a bottom  11   b , a pair of flanges  11   c , and a holder  11   d . The cylindrical part  11   a  surrounds the interior member  10 . The bottom  11   b  is formed in a ring shape and extends radially inward from the lower end of the cylindrical part  11   a . The flanges  11   c  expand radially outward from the upper end of the cylindrical part  11   a  in the opposite direction to form an angle of 180 degrees. The holder  11   d  is formed in a cylindrical shape projecting downward from the outer circumferential end of the bottom  11   b.    
     A convex  11   e  is formed in a ring shape on the upper end surface of the cylindrical part  11   a  over its entire circumference. The tip of the convex  11   e  bends inward in a substantially L-shape in cross-section. The tip of the convex  11   e  does not bend but projects upward as shown in  FIG. 1  before fixture of the upper member  13 . 
     A circular opening  11   f  is formed at the center of the bottom  11   b . The piston rod  3  is inserted through the opening  11   f . The top surface  11   g  of the bottom  11   b  is inclined upward at a constant angle over its entire circumference as it goes radially inward. The top surface  11   g  of the bottom  11   b  is inclined from the horizontal plane at an angle of 5 degrees, for example. 
     A fastening hole  11   h  penetrates each of the flanges  11   c . The shaft of a bolt  4  is inserted through the fastening hole  11   h  and a fastening hole (not shown) in the vehicle body panel  2 . The tip of the shaft is screwed into a nut  5  to engage the flanges  11   c  with the vehicle body panel  2 . 
     The elastic member  12  is made of foamed urethane resin such as methylene diphenyl diisocyanate (MDI). The elastic member  12  covers the entire outer circumference of the interior member  10  and is surrounded by the cylindrical part  11   a  and the bottom  11   b  of the exterior member  11 . The elastic member  12  is in a vertically symmetrical, substantially cylindrical shape. The interior member  10  is inserted into the elastic member  12  to be integral with the elastic member  12  by insert molding. The top surface  12   a  of the elastic member  12  is inclined downward at a constant angle over its entire circumference as it goes radially inward. On the other hand, the bottom surface  12   b  of the elastic member  12  is inclined upward at a constant angle over its entire circumference as it goes radially inward. The upper and bottom surfaces  12   a  and  12   b  of the elastic member  12  are inclined from the horizontal plane at an angle of 5 degrees, for example. The outer circumferential surface  12   c  of the elastic member  12  faces the cylindrical part  11   a  of the exterior member  11  over its entire axial length and over its entire circumference at a distance of d. That is, the elastic member  12  is not in contact with the cylindrical part  11   a  of the exterior member  11  over its entire axial length and over its entire circumference. The distance d between the outer circumferential surface  12   c  of the elastic member  12  and the cylindrical part  11   a  of the exterior member  11  is larger than zero, even if the elastic member  12  is elastically deformed at a maximum due to vibration absorption. On the other hand, the top surface  11   g  of the bottom  11   b  of the exterior member  11  abuts on the bottom surface  12   b  of the elastic member  12  radially from the inside over its entire circumference. This limits radial movement of the elastic member  12 , that is, radially positions the elastic member  12 . That is, the bottom surface  12   b  of the elastic member  12 , and the top surface  11   g  of the bottom  11   b  of the exterior member  11  function as a positioner. 
     The upper member  13  and the bottom  11   b  of the exterior member  11  sandwich and compress the elastic member  12  vertically. With no vibration applied to the strut mount  1 , the elastic member  12  has a vertical compressibility of 20% to 30%. The outer circumferential end of the upper member  13  is fixed to the exterior member  11  by caulking, while being sandwiched between the tip of the convex  11   e  and the cylindrical part  11   a  of the exterior member  11 . A circular opening  13   a  is formed at the center of the upper member  13 . The upper end of the piston rod  3  is inserted through the circular opening  13   a . The bottom surface  13   b  of the upper member  13  is inclined downward at a constant angle over its entire circumference as it goes radially inward. The bottom surface  13   b  of the upper member  13  is inclined from the horizontal plane at an angle of 5 degrees, for example. The bottom surface  13   b  of the upper member  13  abuts on the top surface  12   a  of the elastic member  12  radially from the inside over its entire circumference. This limits the radial movement of the elastic member  12  more reliably. 
     When vibrations are applied to the suspension from a load surface while the vehicle travels, the suspension absorbs the vibrations. If excessive vibrations that are not absorbed by the suspension are applied to the strut mount  1 , the elastic member  12  is elastically deformed so that the strut mount  1  absorbs the excessive vibrations. This reduces vibrations to be transmitted to the vehicle body panel  2 . 
     According to this embodiment 1, the elastic member  12  is radially positioned not to come into contact with the cylindrical part  11   a  of the exterior member  11  over its entire axial length and over its entire circumference. When vibrations are applied to the strut mount  1 , the contact between the elastic member  12  and the cylindrical part  11   a  of the exterior member  11  does not hinder the elastic deformation of the elastic member  12 . This allows the strut mount  1  to absorb the vibrations effectively, thereby allowing the occupant(s) of the vehicle to feel comfortable. 
     Each of the bottom surface  12   b  of the elastic member  12  and the top surface  11   g  of the bottom  11   b  of the exterior member  11  is inclined at a constant angle over its entire circumference. When the elastic member  12  and the exterior member  11  are assembled, there is thus no need to allow one of the elastic member  12  and the exterior member  11  to rotate with respect to the other so that the bottom surface  12   b  of the elastic member  12  circumferentially corresponds to the top surface  11   g  of the bottom  11   b  of the exterior member  11 . That is, the assembly is facilitated. 
     There is also no need to provide any convex or concave for positioning in the elastic member  12 . This configuration simplifies the structure of a mold for the elastic member  12 . 
     The elastic member  12  made of foamed urethane resin improves damping properties while reducing the dynamic/static ratio. 
     Embodiment 2 
       FIGS. 4 and 5  illustrate a strut mount  1  according to an embodiment 2 of the present disclosure. In this embodiment 2, the top surface  11   g  of the bottom  11   b  of the exterior member  11  is not inclined. A groove  14  is formed in a ring shape on the top surface  11   g  of the bottom  11   b  over its entire circumference. The bottom surface  13   b  of the upper member  13  is also not inclined. A groove  15  is formed in a ring shape on the bottom surface  13   b  of the upper member  13  over its entire circumference. 
     Neither the top surface  12   a  nor the bottom surface  12   b  of the elastic member  12  is inclined. A projection  16  is formed in a ring shape on the bottom surface  12   b  of the elastic member  12  over its entire circumference. This projection  16  is fitted into the groove  14  of the bottom  11   b  of the exterior member  11  over its entire circumference, thereby radially positioning the elastic member  12 . That is, the projection  16  of the elastic member  12  and the groove  14  of the exterior member  11  function as a positioner. 
     In addition, a projection  17  is formed in a ring shape on the top surface  12   a  of the elastic member  12  over its entire circumference. This projection  17  is fitted into the groove  15  of the upper member  13  over its entire circumference. This limits the radial movement of the elastic member  12  more reliably. 
     In this embodiment 2, each of the projection  16  of the elastic member  12  and the groove  14  of the exterior member  11  is formed in a ring extending over its entire circumference. When the elastic member  12  and the exterior member  11  are assembled, there is thus no need to allow one of the elastic member  12  and the exterior member  11  to rotate with respect to the other so that the bottom surface  12   b  of the elastic member  12  circumferentially corresponds to the top surface  11   g  of the bottom  11   b  of the exterior member  11 . That is, the assembly is facilitated. 
     Each of the projection  17  of the elastic member  12  and the groove  15  of the upper member  13  is also formed in a ring shape extending over its entire circumference. When the upper member  13  is attached to the exterior member  11 , there is thus no need to allow one of the elastic member  12  and the upper member  13  to rotate with respect to the other so that the top surface  12   a  of the elastic member  12  circumferentially corresponds to the bottom surface  13   b  of the upper member  13 . That is, the assembly is facilitated. 
     Embodiment 3 
       FIGS. 6 and 7  illustrate a strut mount  1  according to an embodiment 3 of the present disclosure. In this embodiment 3, four grooves  18  as radially extending concaves are formed on the top surface  11   g  of the bottom  11   b  of the exterior member  11 . Each groove  18  is spaced apart from the adjacent one of the grooves  18  along the circumference of the top surface  11   g  to form an angle of 90 degrees. In addition, four radially extending grooves  19  are formed on the bottom surface  13   b  of the upper member  13  such that each groove  19  is spaced apart from the adjacent one of the grooves  19  along the circumference of the bottom surface  13   b  to form an angle of 90 degrees. 
     On the other hand, four projections  20  as radially extending convexes are formed on the bottom surface  12   b  of the elastic member  12  such that each projection  20  is spaced apart from the adjacent one of the projections  20  to form an angle of 90 degrees along the circumference of the bottom surface  12   b . These projections  20  are fitted into the grooves  18  on the bottom  11   b  of the exterior member  11  to enable radial and circumferential positioning of the elastic member  12 . That is, the projections  20  of the elastic member  12  and the grooves  18  of the exterior member  11  function as a positioner. 
     Four radially extending projections  21  are formed on the top surface  12   a  of the elastic member  12  such that each projection  21  is spaced apart from the adjacent one of the projections  21  along the circumference of the top surface  12   a  to form an angle of 90 degrees. These projections  21  are fitted into the grooves  19  of the upper member  13 . This limits the radial and circumferential movements of the elastic member  12  more reliably. 
     In this embodiment 3, the circumferential rotation of the elastic member  12  is limited with respect to the exterior member  11  to reduce wear of the elastic member  12 . 
     While the elastic member  12  is made of foamed urethane resin in the embodiments 1 to 3, it may be made of natural rubber or silicone rubber. 
     In the embodiments 2 and 3, the projections  16  and  20  are formed on the bottom surface  12   b  of the elastic member  12  and the grooves  14  and  18  are formed on the top surface  11   g  of the bottom  11   b  of the exterior member  11 . In contrast, the grooves  14  and  18  may be formed on the bottom surface  12   b  of the elastic member  12 , and the projections  16  and  20  may be formed on the top surface  11   g  of the bottom  11   b  of the exterior member  11 . 
     Similarly, in the embodiments 2 and 3, the projections  17  and  21  are formed on the top surface  12   a  of the elastic member  12 , and the grooves  15  and  19  are formed on the bottom surface  13   b  of the upper member  13 . In contrast, the grooves  15  and  19  may be formed on the top surface  12   a  of the elastic member  12 , and the projections  17  and  21  may be formed on the bottom surface  13   b  of the upper member  13 . 
     In the embodiment 3, the four grooves  18  and the four projections  20  are provided. The number of the grooves  18  and the projections  20  is, however, not limited to four, as long as a plurality of grooves  18  and projections  20  are provided to radially position the elastic member  12 . The projections  20  and the grooves  18  may be replaced with convexes in a circular, rectangular, or any other shape in plan view, and concaves to be fitted into the convexes, respectively. In this case as well, the number of the convexes and the concaves is not limited to four, as long as a plurality of convexes and concaves are provided to radially position the elastic member  12 . 
     In the embodiments 1 to 3, the upper member  13  and the bottom  11   b  of the exterior member  11  sandwich the elastic member  12 . In place of the upper member  13 , a part of the vehicle body panel  2  and the bottom  11   b  of the exterior member  11  may sandwich the elastic member  12 . 
     The embodiments described above are to be regarded as illustrative in nature, and not intended to limit the scope of the present disclosure, its equivalents and application. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure is useful as a strut mount interposed between a vehicle body and a piston rod of a shock absorber of a suspension. 
     DESCRIPTION OF REFERENCE CHARACTERS 
     
         
           1  Strut Mount 
           2  Body Panel of Vehicle (Vehicle Body) 
           3  Piston Rod 
           10  Interior Member 
           11  Exterior Member 
           11   a  Cylindrical Part 
           11   b  Bottom 
           11   g  Top Surface 
           12  Elastic Member 
           12   b  Bottom Surface 
           13  Upper Member 
           14  Groove 
           16  Projection 
           18  Groove (Concave) 
           20  Projection (Convex)