Abstract:
The top mount of a strut assembly is capable of being orientated in various positions to accommodate various locations in a vehicle. An orientation device includes a top mount fixture which engages the top mount of the strut assembly. The top mount fixture is positioned within upper tooling and the top mount and top mount fixture are rotated in a first direction until a blocking stop on the upper tooling is engaged. The top mount and the top mount fixture are rotated in the opposite direction until a position stop on the upper tooling is engaged to properly orientate the top mount. Additional position stops can be added to the upper tooling to define additional orientations for the top mount.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a McPherson strut assembly for a motor vehicle. More particularly, the present invention relates to the orientation of the top mount of the McPherson strut assembly which allows for the use of common components on both sides of the vehicle.  
       BACKGROUND OF THE INVENTION  
       [0002]     Strut-type suspension systems are well known in the motor vehicle industry. A telescopic strut normally incorporating a hydraulic damper is used as one of the locating members for the wheel of the motor vehicle. The most common form of a strut-type suspension is the McPherson strut suspension system. The McPherson strut assembly includes a coil spring located concentrically around the telescopic strut which is the shock absorber. The upper end of the McPherson strut assembly includes an upper mounting assembly which is mounted in a tower formed by the vehicle body at a position above the wheel arch of the vehicle.  
         [0003]     The upper mounting assembly typically includes a rebound bumper protected by a dirt shield, an upper spring seat for properly positioning the coil spring of the McPherson strut assembly, a bearing which allows rotation of the piston rod with respect to a top mount which includes bolts which are utilized to secure the upper mounting assembly to the tower formed by the vehicle body.  
         [0004]     As a result of the quest for standardization and the associated cost savings, it is desirable to design symmetrical parts. In the case of the upper mounting assembly, the rebound bumper, the dirt shield, the upper spring seat and the bearing are typically symmetrical components which can be used on both the right and left sides of the vehicle. The top mount, while being similar in design for the right and left sides of the vehicle, it is not a symmetrical component. While the top mount is not a symmetrical component, the identical component may be able to be used on the right and left hand sides of the vehicle if the orientation of the top mount can be specifically set to a first orientation when it is positioned on the right side of the vehicle and specifically set to a second orientation when it is positioned on the left side of the vehicle.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides the art with a system including an orientation device which is capable of automatically aligning the top mount in the first position for the right side of the vehicle and in the second position for the left side of the vehicle. The system includes tooling which includes a first stationary stop for the right side of the vehicle and a second spring mounted stop for the left side of the vehicle.  
         [0006]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0008]      FIG. 1  is an illustration of an automobile using the McPherson strut assemblies in accordance with the present invention;  
         [0009]      FIG. 2  is a side view of one of the front suspension units that incorporate the McPherson strut assembly in accordance with the present invention;  
         [0010]      FIG. 3  is an enlarged cross sectional view of the top mount assembly of the present invention with the orientation tooling engaged with the top mount; and  
         [0011]      FIG. 4  is a top view of the top mount assembly and the orientation tooling illustrated in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0013]     There is shown in  FIG. 1 a  vehicle incorporating a suspension system having the strut assembly in accordance with the present invention and which is designated generally by the reference numeral  10 . Vehicle  10  comprises a rear suspension  12 , a front suspension  14  and a body  16 . Rear suspension  12  has a transversely extending rear axle assembly (not shown) adapted to operatively support the vehicle&#39;s rear wheels  18 . The rear axle assembly is operatively connected to body  16  by means of a pair of shock absorbers  20  and a pair of helical coil springs  22 . Similarly front suspension  14  includes a transversely extending front axle assembly (not shown) to operatively support the vehicle&#39;s front wheels  24 . The front axle assembly is operatively connected to body  16  by means of a second pair of shock absorbers  26  and by a pair of shaped helical coil springs  28 . Shock absorbers  20  and  26  serve to dampen the relative motion of the unsprung portion (i.e. front and rear suspensions  12  and  14 , respectively) and the sprung portion (i.e. body  16 ) of vehicle  10 . While vehicle  10  has been depicted as a passenger car having front and rear axle assemblies, shock absorbers  20  and  26  may be used with other types of vehicles and/or in other types of applications such as vehicles incorporating independent front and/or independent rear suspension systems. Further, the term “shock absorber” as used herein is meant to be dampers in general and thus will include McPherson struts. Also, while front suspension  14  is illustrated having a pair of McPherson struts or shock absorbers  26 , it is within the scope of the present invention to have rear suspension  12  incorporate a pair of McPherson struts or shock absorbers  26  if desired.  
         [0014]     Referring now to  FIG. 2 , the front wheel assembly for vehicle  10  is illustrated in greater detail. Body  16  defines a shock tower  32  comprising sheet metal of vehicle  10  within which is mounted a McPherson strut assembly  34  which comprises a telescoping device in the form of shock absorber  26 , coil spring  28  and a top mount assembly  36 . McPherson strut assembly  34  including shock absorber  26 , coil spring  28  and top mount assembly  36  are attached to vehicle  10  using shock tower  32 . Top mount assembly  36  comprises a top mount  38 , a bearing assembly  40  and an upper spring seat  42 . Top mount  38  comprises an integral molded body and a rigid body member, typically made of stamped steel. Top mount assembly  36  is mounted to body  16  by bolts  48 . Bearing assembly  40  is friction fit within the molded body of top mount  38  to be seated in top mount  38  so that one side of bearing assembly  40  is fixed relative to top mount  38  and shock tower  32 . The second side of bearing assembly freely rotates with respect to the first side of bearing assembly  40 , top mount  38  and shock tower  32 .  
         [0015]     The free rotating side of bearing assembly  40  carries upper spring seat  42  that is clearance fit to the outer diameter of bearing assembly  40 . A jounce bumper  50  is disposed between upper spring seat  42  and shock absorber  26 . Jounce bumper  50  comprises an elastomeric material which is protected by a plastic dirt shield  52 . A bumper cap  54  is located on shock absorber  26  to interface with jounce bumper  50  and plastic dirt shield  52 .  
         [0016]     A lower spring seat  60  is attached to shock absorber  26  and coil spring  28  is disposed between upper spring seat  42  and lower spring seat  60  to isolate body  16  from front suspension  14 . Shock absorber  26  comprises a pressure tube  62 , a piston assembly  64  and a telescoping rod or piston rod  66 . While shock absorber  26  is illustrated as a mono-tube design, it is within the scope of the present invention to utilize a dual-tube shock absorber for shock absorber  26 . Also, while shock absorber  26  is illustrated in  FIG. 2 , it is to be understood that shock absorber  20  may also include the features described herein for shock absorber  26 .  
         [0017]     Prior to the assembly of McPherson strut assembly  34  into vehicle  10 , the pre-assembly McPherson strut assembly  34  is performed. Bumper cap  54 , jounce bumper  50  and dirt shield  52  are assembled to shock absorber  26 . Coil spring  28  is assembled over shock absorber  26  and positioned within lower spring seat  60 . Upper spring seat  42  is assembled onto shock absorber  26  and correctly positioned with respect to coil spring  28 . Bearing assembly  40  is positioned on top of upper spring seat  42  and top mount  38  is positioned on top of bearing assembly  40 . This entire assembly is positioned within an assembly machine which compresses coil spring  28  such that the end of piston rod  66  extends through a bore located within top mount assembly  36 . A retaining nut  68  is threadingly received on the end of piston rod  66  to secure the assembly of McPherson strut assembly  34 .  
         [0018]     Top mount  38  is designed as an identical component for the right and left hand sides of the vehicle but it has a different orientation with respect to shock absorber  26  and its associated bracketry when it is placed on the right or left side of the vehicle.  
         [0019]     Referring now to  FIGS. 3 and 4 , an orientation device in the form of tooling  80  which automatically orientates top mount  38  is illustrated. Tooling  80  comprises a top mount fixture  82  and an upper tool  84  which compresses a base plate  86 , a bearing  88  and a guide  90 . Guide  90  is rotatably disposed within an opening defined by base plate  86  with bearing  88  being disposed between guide  90  and base plate  86 .  
         [0020]     Top mount  38  is engaged by top mount fixture  82 . Top mount  38  with top mount fixture  82  is positioned within upper tool  84  with top mount fixture  82  engaging guide  90 . Bearing  88  is disposed between guide  90  and base plate  86  to permit rotation of top mount  38 , top mount fixture  82  and guide  90  with respect to base plate  86  in order to properly orientate top mount  38  with respect to shock absorber  26 . Base plate  86  includes a blocking stop  92 , a first position stop  94  and a second position stop  96 . A positioning stop  98  which is a part of top mount fixture  82  engages stops  92 ,  94  and  96  to properly orientate top mount  38  with respect to shock absorber  26 .  
         [0021]     During assembly of McPherson strut assembly  34  and the torquing of retaining nut  68 , positioning stop  98  engages blocking stop  92  to prohibit rotation of top mount  38  until the proper torque for retaining nut  68  is achieved. Once the assembly is completed and retaining nut  68  is tightened, top mount  38  is orientated in a counter-clockwise direction as illustrated in  FIG. 4 . Top mount  38  and top mount fixture  82  are rotated counter-clockwise until positioning stop  98  engages first position stop  94 . Second position stop  96  is a spring mounted position stop which moves out of the way of positioning stop  98  when it moves counter-clockwise but second position stop  96  will act as a stop for positioning stop  98  when it is rotated clockwise as shown in  FIG. 4 . If positioning stop  98  engaging first position stop  94  is the correct orientation for top mount  38  for its position in the vehicle such as the right side of the vehicle, control on the amount of torque for retaining nut  68  and a positional control are completed and the assembly process is complete. If the rotation of top mount  38  and top mount fixture  82  to its position where positioning stop  98  engages first position stop  94 , is not the correct position, such as the left side of the vehicle, top mount  38  and top mount fixture  82  are rotated clockwise until second position stop  96  is engaged which is the correct position for the opposite orientation of top mount  38 . The control for the torque on retaining nut  68  and a positional control are completed and the assembly process is complete.  
         [0022]     While tooling  80  is illustrated as having blocking stop  92  and first and second position stops  94  and  96 , it is within the scope of the present invention to have additional spring supported mechanical stops which can be combined with the angular rotation command of the nut runner to provide additional final position stops if desired.  
         [0023]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.  
         [0024]     If the design of the top mount allows to use one or more parts of the top mount to fulfill the function of positioning stop  88  in one or more steps of the process, this considerably simplifies the set-up. This application is considered as within the scope of this invention.