Method for forming a valve assembly

Abstract

The invention relates to a method for forming a valve assembly for a rack and pinion steering apparatus. A pinion having a bore formed therein, a torsion bar having an outer diameter, a valve sleeve, and an input shaft are provided. The input shaft has a bore and an elongated cavity formed therein. The input shaft has an outer diameter less than an inner diameter of the valve sleeve. The torsion bar is forced into the bore of the pinion to friction weld the torsion bar to the pinion. The valve sleeve is positioned over the torsion bar and pinion, and secured with the pinion. The torsion bar is positioned within the bore of the input shaft such that a first end of the torsion bar is positioned coaxially within the elongated cavity of the input shaft. A locking material is inserted into the elongated cavity to lock the torsion bar and the input shaft together.

1 . A method for forming a portion of a rack and pinion steering assembly comprising: 
 (a) providing an input shaft having a bore and an elongated cavity, the bore including a first inner surface defining a first inner diameter and the elongated cavity including a second inner surface defining a second inner diameter which is greater than the first inner diameter;    (b) providing a torsion bar, the torsion bar including an outer surface defining an outer diameter that is less than the second inner diameter of the elongated cavity of the input shaft;    (c) positioning the torsion bar within the bore and the elongated cavity thereby forming a gap between at least portions of the outer surface of the torsion bar and the inner surface of the elongated cavity; and    (d) inserting a material into the gap for securing the input shaft to the torsion bar.    
   
   
       2 . The method defined in  claim 1  wherein the torsion bar outer diameter is less than the first inner diameter of the bore of the input shaft.  
   
   
       3 . The method defined in  claim 1  wherein the torsion bar outer diameter is generally equal to the first inner diameter of the bore of the input shaft.  
   
   
       4 . The method defined in  claim 1  further comprising the steps of providing a port formed through the input shaft extending to the gap and inserting the material through the port and into the gap.  
   
   
       5 . The method defined in  claim 1  wherein the material is a semi-solid material.  
   
   
       6 . The method defined in  claim 4  wherein the semi-solid material is selected from the group consisting of a plastic, a wax, a nylon, a polymer, an epoxy, a gel, and a metal.  
   
   
       7 . The method defined in  claim 1  wherein the gap is isolated from a valve section positioned about the input shaft.  
   
   
       8 . The method defined in  claim 1  further comprising the step of balancing the input shaft and torsion bar, wherein the input shaft and torsion bar are balanced before inserting the locking material into the annular space.  
   
   
       9 . The method defined in  claim 1  further comprising the step of providing a plurality of ports formed through the input shaft, the ports being in fluid communication with the gap.  
   
   
       10 . The method defined in  claim 1  wherein at least a portion of the outer surface of the torsion bar is knurled.  
   
   
       11 . The method defined in  claim 1  wherein the rack and pinion steering assembly is configured to operate with an electronically controlled power assisted steering system.  
   
   
       12 . A method for forming a portion of a rack and pinion steering assembly comprising: 
 (a) providing a torsion bar including an outer surface defining an outer diameter;    (b) providing a pinion having a bore formed therein;    (c) inserting a portion of the torsion bar into the bore of the pinion; and    (c) securing the torsion bar to the pinion.    
   
   
       13 . The method defined in  claim 12  wherein the torsion bar is inserted into the bore using a high velocity insertion method to thereby secure the torsion bar to the pinion.  
   
   
       14 . The method defined in  claim 12  wherein the torsion bar includes an outer surface defining an outer diameter and the bore includes an inner surface defining an inner diameter which is generally equal to the outer diameter of the torsion bar.  
   
   
       15 . The method defined in  claim 12  the bore includes an inner surface defining an inner diameter and the torsion bar includes an outer surface defining an outer diameter and which is generally larger than the inner diameter of the bore.  
   
   
       16 . A method for forming a valve assembly for a rack and pinion steering apparatus comprising: 
 providing a pinion having a bore formed therein;    providing a torsion bar including an outer surface defining an outer diameter that is less than the second inner diameter of the elongated cavity of the input shaft;    providing a valve sleeve;    providing an input shaft having a bore and an elongated cavity, the bore including a first inner surface defining a first inner diameter and the elongated cavity including a second inner surface defining a second inner diameter which is greater than the first inner diameter;    forcing a portion of the torsion bar into the bore of the pinion to secure the torsion bar to the pinion;    positioning the valve sleeve over the torsion bar and pinion;    securing the valve sleeve to the pinion;    positioning a portion of the torsion bar within the bore of the input shaft wherein a first end of the torsion bar is positioned coaxially within the elongated cavity of the input shaft; and    inserting a material into the elongated cavity to secure the torsion bar and the input shaft together.    
   
   
       17 . The method defined in  claim 16  further comprising the step of balancing the valve assembly, wherein the valve assembly is balanced before inserting the locking material into the elongated cavity.  
   
   
       18 . The method defined in  claim 16  wherein an annular space is defined within the elongated cavity of the input shaft between the torsion bar and an inner surface of the elongated cavity; and 
 wherein the locking material is inserted into the annular space.    
   
   
       19 . The method defined in  claim 18  further comprising the step of providing a port formed through the input shaft, the port being in fluid communication with the annular space for inserting the locking material through the port into the annular space.  
   
   
       20 . The method defined in  claim 16  wherein the locking material is one of plastic, wax, nylon, a polymer, epoxy, gel, and metal.  
   
   
       21 . The method defined in  claim 16  wherein the outer diameter of the torsion bar is about the same as the diameter of the bore.  
   
   
       22 . A portion of a valve assembly for a rack and pinion steering assembly comprising: 
 an input shaft having a bore and an elongated cavity, the bore including a first inner surface defining a first inner diameter and the elongated cavity including a second inner surface defining a second inner diameter which is greater than the first inner diameter;    a torsion bar including an outer surface that defines an outer diameter that is less than the second inner diameter of the elongated cavity of the input shaft; and    a locking material;    wherein the torsion bar is located within the bore and the elongated cavity thereby forming a gap between at least portions of the outer surface of the torsion bar and the inner surface of the elongated cavity, and the locking material is positioned within the gap to secure the input shaft to the torsion bar.    
   
   
       23 . The assembly defined in  claim 22  wherein the torsion bar outer diameter is less than the first inner diameter of the bore of the input shaft.  
   
   
       24 . The assembly defined in  claim 22  wherein the torsion bar outer diameter is generally equal to the first inner diameter of the bore of the input shaft.  
   
   
       25 . The assembly defined in  claim 22  further comprising a port formed through the input shaft extending to the gap, wherein the locking material can be inserted into the gap through the port.  
   
   
       26 . The assembly defined in  claim 25  wherein the locking material is selected from the group consisting of a plastic, a wax, a nylon, a polymer, an epoxy, a gel, and a metal.  
   
   
       27 . A portion of a rack and pinion steering assembly comprising: 
 a torsion bar including an outer surface defining an outer diameter;    a pinion having a bore formed therein;    wherein a portion of the torsion bar is positioned in the bore of the pinion and secured thereto.    
   
   
       28 . The assembly defined in  claim 27  wherein the torsion bar includes an outer surface defining an outer diameter and the bore includes an inner surface defining an inner diameter which is generally equal to the outer diameter of the torsion bar.  
   
   
       29 . The assembly defined in  claim 27  wherein the bore includes an inner surface defining an inner diameter and the torsion bar includes an outer surface defining an outer diameter and which is generally larger than the inner diameter of the bore.  
   
   
       30 . A valve assembly for a rack and pinion steering apparatus comprising: 
 a pinion having a bore formed therein;    a torsion bar including an outer surface defining an outer diameter that is less than the second inner diameter of the elongated cavity of the input shaft;    a valve sleeve; and    an input shaft having a bore and an elongated cavity, the bore including a first inner surface defining a first inner diameter and the elongated cavity including a second inner surface defining a second inner diameter which is greater than the first inner diameter;    wherein a portion of the torsion bar is forced into the bore of the pinion to secure the torsion bar to the pinion;    the valve sleeve is positioned over the torsion bar and pinion;    the valve sleeve is secured to the pinion;    a portion of the torsion bar is positioned within the bore of the input shaft such that a first end of the torsion bar is positioned coaxially within the elongated cavity of the input shaft; and    a material is inserted into the elongated cavity to secure the torsion bar and the input shaft together to form the valve assembly.