Apparatus and method for manufacture of a driveshaft by a pulsed magnetic force process

An apparatus for forming a driveshaft having a shaft and a coupling end part of radial dimensions larger than those of the shaft, the apparatus comprising:

• one or two forming assemblies for forming one end or two ends of a driveshaft, respectively;
• the one or two forming assemblies comprising each a holder and a forming unit;
• the holder is adapted to receive and hold a driveshaft end part pre-assembly;
• the pre-assembly consisting of two components, of which one is an end section of an elongated shaft that defines an axis, and the other is a coupling end part member, either the shaft end section or a portion of the end part member having a generally cylindrical shape with an axial cylindrical cavity that accommodates an axial cylindrical portion of the other snuggly fitted therewithin, the end section and said portion defining together a cylindrical joining section of the two components;
• the forming unit comprising an unbroken primary coil connected to a current discharge circuitry for generating an intense current pulse, and two or more inserts, each of which constitutes a section of a forming coil device accommodated within an opening defined by the primary coil, the opening being of a diameter sufficient to permit the coupling end part to pass therethrough, and defining in turn a forming space to accommodate said joining section;
• the inserts being made of or having their external layer made of an electrically conducting layer and being attached to one another at attachment faces with an electrically insulating layer between them.

An apparatus for forming a driveshaft having a shaft and a coupling end part, the apparatus comprising:

• one or two forming assemblies for forming one end or two ends of a driveshaft, respectively;
• the one or two forming assemblies comprising each a holder, a forming unit and an auxiliary device;
• the holder is adapted to receive and hold a driveshaft end part pre-assembly;
• the pre-assembly consisting of two components, of which one is an end section of an elongated shaft that defines an axis, and the other is a coupling end part member, either the shaft end section or a portion of the end part member having a generally cylindrical shape with an axial cylindrical cavity that accommodates an axial cylindrical portion of the other snuggly fitted therewithin, the end section and said portion defining together a cylindrical joining section of the two components;
• the forming unit comprising a forming coil device defining a forming space for accommodating said joining section and a current generating unit for generating an intense current pulse within the forming coil unit to yield a PMF sufficiently strong to yield joining of the two parts of the joining section;
• the forming coil device being assembled from two or more coil sections firmly attached to one another at attachment faces thereof, which can be disassembled to permit release of the so formed driveshaft end part;
• and the auxiliary device, being adapted for temporary assembly with the coupling end part member to yield together a body having axial symmetry.

A method for forming a driveshaft having a shaft and a coupling end part of radial dimensions larger than those of the shaft, the method comprising:

• (a) providing a shaft, the shaft defining an axis, and a coupling end part member;
• either the shaft end section or a portion of the end part member having a generally cylindrical shape with an axial cylindrical cavity and the other having an axial cylindrical portion that can fit within said cavity, and fitting said cylindrical portion into said cavity to define together a joining section with an external cylindrical shape;
• (b) fitting a forming coil device around said joining section, the forming coil device being assembled from two or more coil sections firmly attached to one another at attachment faces thereof and being associated with a current generating unit;
• (c) generating an intense current pulse through said forming coil device to generate a pulsed magnetic force (PMF) sufficient for joining the two parts of the joining section;
• and (d) disassembling the forming coil device to free the so formed end section of the driveshaft;
• steps (a)-(d) being performed either simultaneously for the two ends of the shaft to simultaneously join two coupling end part members one to each end of the shaft, or being performed in sequence by first carrying out steps (a)-(d) for joining one coupling end part member to one end of the shaft and then repeating these steps for joining another coupling end part member to the other end of the shaft, wherein said current generating unit delivers a current pulse only through an unbroken conductor, and wherein at least one of said coil sections of said forming coil device contributes to said PMF through inductively generated current.

A method for forming a driveshaft having a shaft and a coupling end part of radial dimensions larger than those of the shaft, the method comprising:

• (a) providing a shaft, the shaft defining an axis, and a coupling end part member;
• either the shaft end section or a portion of the end part member having a generally cylindrical shape with an axial cylindrical cavity and the other having an axial cylindrical portion that can fit within said cavity, and fitting said cylindrical portion into said cavity to define together a joining section with an external cylindrical shape;
• (b) fitting a forming coil device adjacent said joining section, the forming coil device comprises an unbroken primary coil connected to a current discharge circuitry for generating an intense current pulse, and two or more inserts, each of which constitutes a section of a forming coil device accommodated within an opening defined by the primary coil, the opening being of a diameter sufficient to permit the coupling end part to pass therethrough, and defining in turn a forming space to accommodate said joining section;
• the inserts being made of or having their external layer made of an electrically conducting layer and being attached to one another at attachment faces with an electrically insulating layer between them;
• (c) generating an intense current pulse through said primary coil to induce a forming current in the inner face of the forming coil device to generate a pulsed magnetic force (PMF) sufficient for joining the two parts of the joining section;
• and (d) disassembling said inserts and removing the primary coil by axially moving either the primary coil or the formed driveshaft end;
• steps (a)-(d) being performed either simultaneously for the two ends of the shaft to simultaneously join two coupling end part members one to each end of the shaft, or being performed in sequence by first carrying out steps (a)-(d) for joining one coupling end part member to one end of the shaft and then repeating these steps for joining another coupling end part member to the other end of the shaft.

A method for forming a driveshaft having a shaft and a coupling end part of radial dimensions larger than those of the shaft, the method comprises:

• (a) providing a shaft, the shaft defining an axis, and a coupling end part member;
• either the shaft end section or a portion of the end part member having a generally cylindrical shape with an axial cylindrical cavity and the other having an axial cylindrical portion that can fit within said cavity, and fitting said cylindrical portion into said cavity to define together a joining section with an external cylindrical shape;
• (b) fitting a forming coil device around said joining section, the forming coil device being assembled from two or more coil sections firmly attached to one another at attachment faces thereof and being associated with a current generating unit;
• (c) temporarily fitting an auxiliary device to said coupling end part member to form together a body having an axial symmetry;
• (d) generating an intense current pulse through said forming coil device to generate a pulsed magnetic force (PMF) sufficient for joining the two parts of the joining section;
• and (e) removing the auxiliary device from the coupling end part and disassembling the forming coil device to free the so formed end section of the driveshaft;
• steps (a)-(e) being performed either simultaneously for the two ends of the shaft to simultaneously join two coupling end part members one to each end of the shaft, or being performed in sequence by first carrying out steps (a)-(e) for joining one coupling end part member to one end of the shaft and then repeating these steps for joining another coupling end part member to the other end of the shaft.