Abstract:
A clamp isolator for an intermediate shaft assembly comprising an intermediate shaft having a free end and a secondary shaft having a free end. The clamp isolator includes a clamping portion and an isolation portion and interconnects the two shafts. The clamping portion is configured to rigidly clamp upon one of the shaft free ends and the isolation portion includes a substantially hollow housing configured to receive an isolation bushing therein. The isolation bushing has an opening therein configured to receive the other of the shaft free ends.

Description:
BACKGROUND  
         [0001]    The present invention relates to steering columns. More particularly, the present invention relates to an intermediate shaft assembly including an isolation bushing.  
           [0002]    A steering intermediate shaft is often utilized to connect a gear input shaft to an upper shaft, for example, either an upper intermediate shaft or directly to the steering column shaft. The upper shaft and the intermediate shaft typically each include a yoke at one end, the yokes being interconnected to provide a universal joint. The opposite end of the intermediate shaft is generally fairly rigidly interconnected with the gear input shaft. As such, any noise or other vibration between the intermediate shaft and the gear input shaft carries up the steering column. Some prior art devices have utilized a damping isolation feature proximate the universal joint, however, such feature does not always provide sufficient damping and also is limited in its flexibility since it is limited to the position of the universal joint.  
         SUMMARY  
         [0003]    The present invention provides a clamp isolator for an intermediate shaft assembly. The assembly comprises an intermediate shaft having a free end and a secondary shaft having a free end. The clamp isolator interconnects the two shafts. The isolator includes a clamping portion and an isolation portion. The clamping portion is configured to rigidly clamp upon the free end of one of the shafts. The isolation portion includes a substantially hollow housing configured to receive an isolation bushing therein. The isolation bushing has an opening therein configured to receive the free end of the other shaft. A pin or the like secures the shaft free end within the bushing within the isolation housing.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]    [0004]FIG. 1 is a plan view of an intermediate shaft assembly incorporating a clamp isolator according to a first embodiment of the present invention.  
         [0005]    [0005]FIG. 2 is an exploded oblique view of the clamp isolator of FIG. 1.  
         [0006]    [0006]FIG. 3 is an exploded elevational view of the clamp isolator of FIG. 1.  
         [0007]    [0007]FIG. 4 is a cross-sectional elevational view of the clamp isolator of FIG. 1.  
         [0008]    [0008]FIG. 5 is a cross-sectional view along the line  5 - 5  in FIG. 1.  
         [0009]    [0009]FIG. 6 is a plan view of an alternative intermediate shaft assembly incorporating a clamp isolator according to a second embodiment of the present invention.  
         [0010]    [0010]FIG. 7 is an oblique view of an isolator body blank.  
         [0011]    [0011]FIG. 8 is an oblique view of a machined isolator body. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]    The present invention will be described with reference to the accompanying drawing figures wherein like numbers represent like elements throughout. Certain terminology, for example, “top”, “bottom”, “right”, “left”, “front”, “frontward”, “forward”, “back”, “rear” and “rearward”, is used in the following description for relative descriptive clarity only and is not intended to be limiting.  
         [0013]    Referring to FIG. 1, an intermediate shaft assembly  10  incorporating a clamp isolator  20  in accordance with a first embodiment of the present invention is shown. The shaft assembly  10  generally includes a shaft  12  terminating at one end with a yoke  14  which is part of a universal joint  16 . The opposite end of the shaft  12  is connected to a first end of the clamp isolator  20  via a pin  48  or the like. The opposite end of the clamp isolator  20  is clamped to a gear input shaft  18 .  
         [0014]    The preferred clamp isolator  20  is shown in FIGS.  2 - 4 . The clamp isolator  20  includes a unitary body  22  defining a clamp portion  30  and an isolator portion  40 . The clamp portion  30  includes a clamp block  32  surrounding a shaft receiving bore  34 . The bore  34  is configured to correspond to the configuration of the shaft  18  to be secured therein. The clamp block  32  has a compression slot  36  extending through the upper surface of the block  32  to the receiving bore  34 . A bolt  38  or the like is inserted into and tightened within a bolt bore  37  to narrow the compression slot  36  to tighten the clamp block  32  about a gear shaft  18  (see FIG. 1) or other shaft positioned in the shaft receiving bore  34 . A cross slot  39  extends partially through the isolator body  22  between the clamp portion  30  and the isolator portion  40  such that the isolator portion  40  does not interfere with opening and closing of the clamp block  32 .  
         [0015]    The isolator portion  40  preferably includes a substantially hollow tube  42  extending opposite the clamp portion  30  with an open end  44  for receiving an isolation bushing  50  and the shaft  12 . The tube  42  has a pin receiving bore  46  therethrough for receiving a shaft securing pin  48  or the like. The tube  42  is shown having a cylindrical configuration, but other configurations may also be utilized. Additionally, while the tube  42  is shown having a generally continuous surface, other configurations may also be utilized.  
         [0016]    The isolation bushing  50  is preferably manufactured from rubber or some other at least partially elastomeric material. For example, a suitable bushing may be complete rubber, for example, Torrington Co. part no. 42FP024618 manufactured by BRC Rubber of Fort Wayne, Ind. or the bushing may have rubber or the like positioned between metallic sleeves, for example, Torrington Co. part no. 42FP024315 manufactured by Barry Controls of Brighton, Mass. While rubber is preferred, other materials may also be used. The bushing  50  preferably has an outer configuration  52  substantially the same as the inside configuration of the tube  52  and an inner opening  54  having a configuration substantially the same as the configuration of the shaft  12  to be received therein. The bushing  50  has a through bore  56  that aligns with the tube pin receiving bore  46  to allow passage of the shaft securing pin  48 .  
         [0017]    Referring to FIG. 5, interconnection of a gear input shaft  18  and intermediate shaft  12  utilizing clamp isolator  20  is shown. The isolation bushing  50  is positioned in the hollow tube  42 . The free end of the intermediate shaft  12  is positioned within the bushing  50  and a securing pin  48  or the like is inserted to secure the shaft  12  within the tube  42 . The gear input shaft  18  is inserted into the shaft receiving bore  34  and the bolt  38  is tightened to narrow the slot  36 . The clamp block  32  thereby clamps about the gear input shaft  18 . The clamp isolator  20  provides a secure connection between the shafts  12  and  18  while the bushing  50  provides noise, vibration and harshness damping.  
         [0018]    Referring to FIG. 6, an alternative intermediate shaft assembly  10 ′ is shown. The assembly  10 ′ includes a shaft  12  terminating at one end with a yoke  14  which is part of a universal joint  16  that connects to the gear input shaft  18 . The opposite end is connected to a first end of clamp isolator  20 ′. The clamp isolator  20 ′ is substantially the same as the clamp isolator  20  described above except that the clamp portion  30 ′ shaft receiving bore  34 ′ is configured to receive the intermediate shaft  12 , as opposed to a gear input shaft. The isolation portion  40 ′ receives and secures the upper shaft  13 , whether an upper intermediate shaft, column shaft or otherwise. Alternatively, the clamp isolator  20 ′ can be reversed such that the clamp portion  30 ′ is clamped to the upper shaft  13  and the isolation portion  40 ′ receives the intermediate shaft  12 .  
         [0019]    Referring to FIGS. 7 and 8, a preferred method of forming the tube clamp isolator  20  will be described. The unitary isolator body  22  is preferably cast from a light weight material, for example, aluminum. The isolator body  22  is cast with the tube  42  hollowed and the shaft receiving bore  34  positioned and configured as desired. The compression slot  36  and the cross slot  39  are cut or otherwise machined into the body  22 . The bolt receiving bore  37  and the pin receiving bore  46  are machined. The bushing  50  is inserted into the hollow tube  42  and the isolator  20  is ready for use.