Method for design respective manufacture of threads in a threaded member, a threaded member manufactured according to the method, and a bolted joint including such a member

Abstract

The invention relates to a method in the formation of threads of a thread-provided element intended to be included as one of two thread-provided parts in a bolted joint. The bolted joint comprises a part ( 2 ) having an internal thread and a part ( 1 ) having an external thread, and the threads of the respective parts are initially formed according to the ISO and/or Unified basic profile having an initial play in both the radial and axial direction, when said parts are tightened together. The invention is characterized in that the threads of said thread-provided element are formed so that an additional play (ΔS a ) between said two thread-provided parts is obtained in the axial direction, at the same time as said initial play in radial direction remains substantially unaltered, the part of the bolted joint which consists of the thread-provided element no longer having ISO/Unified basic profile. The invention also relates to a method for the manufacture of threads, as well as corresponding thread-provided element and bolted joint.

1 . Method for forming threads of a thread-provided part which is intended to be one of two thread-provided parts in a bolted joint, the method comprising: 
 providing a first part having an internal thread and a second part having an external thread wherein the first and second parts are screwed together with the second part is intended to be inside the first part, and wherein the second part having the external thread intended to be prestressed with an axial tensile force, the threads of the respective parts initially being formed according to a basic profile which provides an initial play in both radial and axial directions, when the parts are screwed together and are unstressed,    further forming the threads of at least one of the thread-provided parts such that an additional play ΔS a  between the two thread-provided parts is obtained in the axial direction, while the initial play in the radial direction remains substantially unaltered, and the at least one of parts of the bolted joint which is formed to provide the additional play, no longer having the basic profile.    
   
   
       2 . Method according to  claim 1 , wherein the at least one thread-provided part is the first part having the internal thread which includes threads formed so that the additional axial play together with the initial axial play corresponds to at least a maximum elongation which the second part having the external thread is expected to undergo, at the prestress, within an area where the parts cooperate.  
   
   
       3 . Method according to  claim 1 , wherein the at least one thread-provided part is the second part having the external thread, and the external thread being formed so that the additional axial play together with the initial axial play corresponds to at least a maximum elongation which the second part having the external thread is expected to undergo, at the prestress, within an area where the second part having the external thread co-operates with the first part having the internal thread.  
   
   
       4 . Method according to  claim 1 , further comprising increasing the axial play with maintained thread coverage.  
   
   
       5 . Method according to  claim 1 , wherein the threads of the parts have respective thread ridges, of an initial width, the method further comprising decreasing the width of the thread ridge of the at least one thread-provided part by a measure corresponding to the desired additional axial play.  
   
   
       6 . Method according to  claim 5 , wherein the thread ridges have opposite flanks, and the decreasing of the width of the thread ridge occurs on one of the flanks of the ridge.  
   
   
       7 . Method according to  claim 5 , wherein the decreasing of the width of the thread ridge is distributed on both opposite flanks thereof.  
   
   
       8 . A thread-provided part produced according to the method of  claim 1 .  
   
   
       9 . A bolted joint comprising a first part having an internal thread and a second part having an external thread, and the parts are two thread-provided parts which are tightened together with each other for forming the joint, wherein at least one of the thread-provided parts is produced according to the method of  claim 1 .  
   
   
       10 . A method for producing of threads of a thread-provided part to be included as one of two thread-provided parts of a bolted joint, wherein the bolted joint comprises a first part having an internal thread and a second part having an external thread, the thread producing method comprising manufacturing the threads using a cutting tool in the threads according to a standard with appurtenant initial axial and radial play, and then axially advancing the cutting tool only an additional distance, while retaining with unaltered radial position, for achieving an additional selected axial play ΔS a , the additional distance corresponding to the additional axial play.  
   
   
       11 . A thread-provided part produced according to the method of  claim 10 .  
   
   
       12 . A bolted joint comprising two thread provided parts, with one part screwed into the other part, at least one of the thread-provided parts being produced according to the method of  claim 10 .  
   
   
       13 . The method according to  claim 1 , wherein the basic profile with which the threads of the respective parts are formed according to at least one of the ISO and Unified basic profile.  
   
   
       14 . The method according to  claim 10 , wherein the threads are manufactured according to at least one of the ISO and Unified basic profile.