CA2612998A1 - Electromagnetic (em) metal forming techniques for hydroforming pierce punches drive via em energy, for forming tubular metal workpieces over a mandrel, and for making camshaft assemblies - Google Patents
Electromagnetic (em) metal forming techniques for hydroforming pierce punches drive via em energy, for forming tubular metal workpieces over a mandrel, and for making camshaft assemblies Download PDFInfo
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Abstract
An apparatus and a method of forming a metal blank into a structural member of a predetermined shape are provided by placing a metal blank into a hydroforming mold.
The hydroforming mold comprises an electromagnetic trimming/piercing assembly.
The metal blank is hydroformed into a hydroformed member. An electric discharge circuit is energized to create an electromagnetic force sufficient to drive an electromagnetic driver. The electric discharge circuit is discharged to drive the electromagnetic driver toward the hydroformed member. The electromagnetic driver comprises a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape. Structural members formed by the method and apparatus of the instant invention can be used, for example, in automotive applications. Furthermore, a method of making a camshaft assembly is provided. A plurality of cam and journal elements are provided, wherein each element includes an axial opening. The plurality of cam and journal elements are secured in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis. A hollow shaft is inserted through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements. Electromagnetic energy is provided to at least a portion of the hollow shaft along an axial extent of the hollow shaft to expand the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam elements and journal and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in the predetermined fixed orientation and spacing.
The hydroforming mold comprises an electromagnetic trimming/piercing assembly.
The metal blank is hydroformed into a hydroformed member. An electric discharge circuit is energized to create an electromagnetic force sufficient to drive an electromagnetic driver. The electric discharge circuit is discharged to drive the electromagnetic driver toward the hydroformed member. The electromagnetic driver comprises a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape. Structural members formed by the method and apparatus of the instant invention can be used, for example, in automotive applications. Furthermore, a method of making a camshaft assembly is provided. A plurality of cam and journal elements are provided, wherein each element includes an axial opening. The plurality of cam and journal elements are secured in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis. A hollow shaft is inserted through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements. Electromagnetic energy is provided to at least a portion of the hollow shaft along an axial extent of the hollow shaft to expand the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam elements and journal and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in the predetermined fixed orientation and spacing.
Description
Doc. No. 705561 CA Patent ELECTROMAGNETIC (EM) METAL FORMING TECHNIQUES FOR
HYDROFORMING PIERCE PUNCHES DRIVEN VIA EM ENERGY, FOR
FORMING TUBULAR METAL WORKPIECES OVER A MANDREL, AND
FOR MAKING CAMSHAFT ASSEMBLIES
Field Of The Invention [0001] The present invention generally relates to the field of manufacturing vehicle parts, and more particularly to the field of electromagnetic metal forming techniques for hydroforming and finishing vehicle parts, for forming tubular metal workpieces, and for making camshaft assemblies.
Back2round Of The Invention [0002] Hydroforming methods are commonly known as a means for shaping hollow metal blanks into a component of a predetermined configuration. In particular, a typical hydroforming operation involves the placement of a tubular metal blank into a hydroforming die cavity and providing a high pressure fluid to the interior of the blank to cause the blank to expand into conformity with the surfaces defining the die cavity.
More particularly, the opposite longitudinal ends of the tubular metal blank are sealed, and high pressure water is provided through a hydroforming port or ram sealing one of the tubular ends. The fluid provided within the tube is pressurized by a conventional intensifier.
100031 Hydroformed components may be further processed after hydroforming to their final configuration. Finishing operations may be performed, for example, by laser cutting. However, laser cutting is considered a relatively time consuming and expensive procedure.
[0004] U.S. Patent No. 6,751,994 issued to Horton et al. and entitled "Method and Apparatus for Forming a Structural Member" discloses an apparatus and method for using electromagnetic energy to form structural members of the type that may be used, for example, in the construction of motor vehicles. The method disclosed therein may utilize one or more electromagnetic discharges to move the metallic material of a wall Doc. No. 705561 CA Patent or walls of a workpiece against a die surfaces of a processing die to trim, pierce and/or shape the workpiece. The workpiece is first hydroformed in a hydroforming die and then transferred to the processing die. The hydroformed workpiece is placed in the processing die and a discharging element is inserted into the workpiece so that the walls of the workpiece are positioned between the surfaces of the die cavity of the processing die an dthe discharging element. When the discharging element is actuated, the metallic wall of the workpiece presses against the surfaces of the die cavity of the processing die. The surfaces of the processing die may be constructed to trim, pierce, and/or shape the wall of the hydroformed workpiece.
[0005] It is often necessary that hydroformed parts have various holes and openings, for fasteners, location features, etc. As described heretofore, it is possible to punch or drill these holes subsequent to the hydroforming operation, but it would be desirable to do it simultaneously, in-die. This obviates the need to form the holes in a subsequent operation, such as by drilling, plasma cutting, or laser cutting, after the part has been removed from the hydroforming dies. It is known that one or more holes required in a hydroformed part may be pierced in the part while the part remains in the dies by using the hydroforming pressure to effect the piercing immediately following the forming of the part with this pressure. Such piercing operations performed with the hydroforming fluid used to form the part are referred to as hydropiercing.
[0006] A prior known hydroforming apparatus including an in-die hydropiercing apparatus is disclosed by Shimanovski et al. in U.S. Patent No. 5,398,533.
[0007] Typically, the hydropiercing is accomplished by hydraulic cylinders. If more than one hole or opening is to be provided in the hydroformed part, the sequencing of the hydraulics for multiple cylinders is an issue which needs to be addressed.
During the hydropiercing sequence of the hydroform cycle, several hydraulic cylinders of various diameters attempt to stroke, i.e. move forward, simultaneously. This action requires a tremendous amount of oil volume and pressure which is very costly to achieve in traditional hydraulic systems. The loss of flow and pressure during the hydropiercing sequence can cause some cylinders to stroke after others which in turn Doc. No. 705561 CA Patent can result in poor quality pierced holes. In order to obviate these problems it is commonly attempted to sequence the hydraulic cylinders to force them to pierce at the same time. Alternatively, it is attempted to size the hydraulic system to compensate therefore and to use accumulators. These attempts require considerable effort while being very costly and not very reliable.
[0008] Another issue in traditional hydropiercing systems is the die integrity due to large hydraulic cylinders that are machined into the die cavity. The hydraulic cylinders required for hydropiercing are large in size and require lots of material to be removed from the primary hydroform cavity for mounting.
[0009] Furthermore, traditional hydropiercing systems are expensive in order to integrate the hydraulics and cylinders since the machining required for mounting, the valving, and the piping of oil add tremendously to the costs of the hydroforming dies.
[0010] Therefore, it is desirable to provide a method and an apparatus to reduce the problems with traditional hydropiercing systems.
[0011] It is desirable to provide a hydropiercing process and apparatus wherein the hydraulic cylinders would operate more rapidly and simultaneously.
[0012] It is desirable to provide a hydropiercing apparatus that is smaller than a prior art hydropiercing apparatus and packages more easily into the hydroforming die.
[0013] Furthermore, it is desirable to provide a more cost effective hydropiercing process and apparatus [0014] Metal spinning is an efficient and flexible metal forming process to produce axial-symmetric hollow bodies in a variety of shapes. Metal spinning allows to form a wide range of materials, such as steel, stainless steels, light metals like aluminum and titanium and non-ferrous high-density metals like brass, nickel, and tungsten.
[0015] A metal disc blank or pre-form that is produced by drawing or stamping is concentrically clamped against the spinning mandrel by the pressurized tailstock. The Doc. No. 705561 CA Patent main spindle then starts to rotate while a spinning roller makes frictional contact progressively reforming the original blank or perform until the metal lies internally on the spinning mandrel.
[0016] One method of metal spinning and flow forming is tube spinning. A
tubular preform is placed on a cylindrical mandrel typically made of a hardenable steel.
Forming rollers with specific profiles are set at predetermined distances from each other and the mandrel. When the tube spinning machine is activated and in dependence upon the configuration of the machine, the rollers either traverse the mandrel or the mandrel passes between the stationary, rotating rollers. The result is a tube whose material has been significantly cold worked and dimensionally controlled by the spinning process to yield a product with uniform or variable wall thickness, diameter, and length features.
[0017] When the preform has one closed or semi-closed end, such as a vessel, the bottom typically rests against the face of the mandrel while the material being flowformed is moved in the same directions as the rollers. This technique is called forward flowforming. When the preform has two open ends, such as a tube, reverse flowforming is used, in which the force applied by the rollers pushes the material against a serrated ring at the end of the mandrel. The ring is driven by and rotates with the mandrel. As the rollers compress and extrude the material against the ring, the material flows under, and in the opposite direction, of the rollers.
[0018] Using multiple rollers that may be staggered and set at different gaps, multiple reductions can be formed in a single machine pass.
[0019] However, the spinning technology is slow and expensive, particularly having regard to automotive applications.
[0020] It is desirable to provide an alternative process to the spinning metal forming technology.
[0021] It is desirable to provide a metal forming technique with a shorter cycle time and hence lower cost.
HYDROFORMING PIERCE PUNCHES DRIVEN VIA EM ENERGY, FOR
FORMING TUBULAR METAL WORKPIECES OVER A MANDREL, AND
FOR MAKING CAMSHAFT ASSEMBLIES
Field Of The Invention [0001] The present invention generally relates to the field of manufacturing vehicle parts, and more particularly to the field of electromagnetic metal forming techniques for hydroforming and finishing vehicle parts, for forming tubular metal workpieces, and for making camshaft assemblies.
Back2round Of The Invention [0002] Hydroforming methods are commonly known as a means for shaping hollow metal blanks into a component of a predetermined configuration. In particular, a typical hydroforming operation involves the placement of a tubular metal blank into a hydroforming die cavity and providing a high pressure fluid to the interior of the blank to cause the blank to expand into conformity with the surfaces defining the die cavity.
More particularly, the opposite longitudinal ends of the tubular metal blank are sealed, and high pressure water is provided through a hydroforming port or ram sealing one of the tubular ends. The fluid provided within the tube is pressurized by a conventional intensifier.
100031 Hydroformed components may be further processed after hydroforming to their final configuration. Finishing operations may be performed, for example, by laser cutting. However, laser cutting is considered a relatively time consuming and expensive procedure.
[0004] U.S. Patent No. 6,751,994 issued to Horton et al. and entitled "Method and Apparatus for Forming a Structural Member" discloses an apparatus and method for using electromagnetic energy to form structural members of the type that may be used, for example, in the construction of motor vehicles. The method disclosed therein may utilize one or more electromagnetic discharges to move the metallic material of a wall Doc. No. 705561 CA Patent or walls of a workpiece against a die surfaces of a processing die to trim, pierce and/or shape the workpiece. The workpiece is first hydroformed in a hydroforming die and then transferred to the processing die. The hydroformed workpiece is placed in the processing die and a discharging element is inserted into the workpiece so that the walls of the workpiece are positioned between the surfaces of the die cavity of the processing die an dthe discharging element. When the discharging element is actuated, the metallic wall of the workpiece presses against the surfaces of the die cavity of the processing die. The surfaces of the processing die may be constructed to trim, pierce, and/or shape the wall of the hydroformed workpiece.
[0005] It is often necessary that hydroformed parts have various holes and openings, for fasteners, location features, etc. As described heretofore, it is possible to punch or drill these holes subsequent to the hydroforming operation, but it would be desirable to do it simultaneously, in-die. This obviates the need to form the holes in a subsequent operation, such as by drilling, plasma cutting, or laser cutting, after the part has been removed from the hydroforming dies. It is known that one or more holes required in a hydroformed part may be pierced in the part while the part remains in the dies by using the hydroforming pressure to effect the piercing immediately following the forming of the part with this pressure. Such piercing operations performed with the hydroforming fluid used to form the part are referred to as hydropiercing.
[0006] A prior known hydroforming apparatus including an in-die hydropiercing apparatus is disclosed by Shimanovski et al. in U.S. Patent No. 5,398,533.
[0007] Typically, the hydropiercing is accomplished by hydraulic cylinders. If more than one hole or opening is to be provided in the hydroformed part, the sequencing of the hydraulics for multiple cylinders is an issue which needs to be addressed.
During the hydropiercing sequence of the hydroform cycle, several hydraulic cylinders of various diameters attempt to stroke, i.e. move forward, simultaneously. This action requires a tremendous amount of oil volume and pressure which is very costly to achieve in traditional hydraulic systems. The loss of flow and pressure during the hydropiercing sequence can cause some cylinders to stroke after others which in turn Doc. No. 705561 CA Patent can result in poor quality pierced holes. In order to obviate these problems it is commonly attempted to sequence the hydraulic cylinders to force them to pierce at the same time. Alternatively, it is attempted to size the hydraulic system to compensate therefore and to use accumulators. These attempts require considerable effort while being very costly and not very reliable.
[0008] Another issue in traditional hydropiercing systems is the die integrity due to large hydraulic cylinders that are machined into the die cavity. The hydraulic cylinders required for hydropiercing are large in size and require lots of material to be removed from the primary hydroform cavity for mounting.
[0009] Furthermore, traditional hydropiercing systems are expensive in order to integrate the hydraulics and cylinders since the machining required for mounting, the valving, and the piping of oil add tremendously to the costs of the hydroforming dies.
[0010] Therefore, it is desirable to provide a method and an apparatus to reduce the problems with traditional hydropiercing systems.
[0011] It is desirable to provide a hydropiercing process and apparatus wherein the hydraulic cylinders would operate more rapidly and simultaneously.
[0012] It is desirable to provide a hydropiercing apparatus that is smaller than a prior art hydropiercing apparatus and packages more easily into the hydroforming die.
[0013] Furthermore, it is desirable to provide a more cost effective hydropiercing process and apparatus [0014] Metal spinning is an efficient and flexible metal forming process to produce axial-symmetric hollow bodies in a variety of shapes. Metal spinning allows to form a wide range of materials, such as steel, stainless steels, light metals like aluminum and titanium and non-ferrous high-density metals like brass, nickel, and tungsten.
[0015] A metal disc blank or pre-form that is produced by drawing or stamping is concentrically clamped against the spinning mandrel by the pressurized tailstock. The Doc. No. 705561 CA Patent main spindle then starts to rotate while a spinning roller makes frictional contact progressively reforming the original blank or perform until the metal lies internally on the spinning mandrel.
[0016] One method of metal spinning and flow forming is tube spinning. A
tubular preform is placed on a cylindrical mandrel typically made of a hardenable steel.
Forming rollers with specific profiles are set at predetermined distances from each other and the mandrel. When the tube spinning machine is activated and in dependence upon the configuration of the machine, the rollers either traverse the mandrel or the mandrel passes between the stationary, rotating rollers. The result is a tube whose material has been significantly cold worked and dimensionally controlled by the spinning process to yield a product with uniform or variable wall thickness, diameter, and length features.
[0017] When the preform has one closed or semi-closed end, such as a vessel, the bottom typically rests against the face of the mandrel while the material being flowformed is moved in the same directions as the rollers. This technique is called forward flowforming. When the preform has two open ends, such as a tube, reverse flowforming is used, in which the force applied by the rollers pushes the material against a serrated ring at the end of the mandrel. The ring is driven by and rotates with the mandrel. As the rollers compress and extrude the material against the ring, the material flows under, and in the opposite direction, of the rollers.
[0018] Using multiple rollers that may be staggered and set at different gaps, multiple reductions can be formed in a single machine pass.
[0019] However, the spinning technology is slow and expensive, particularly having regard to automotive applications.
[0020] It is desirable to provide an alternative process to the spinning metal forming technology.
[0021] It is desirable to provide a metal forming technique with a shorter cycle time and hence lower cost.
Doc. No.705561 CA Patent [0022] It is further desirable to provide a novel metal forming technique using an external electromagnetic coil over a mandrel.
100231 In the history of the internal combustion engine, camshafts were cast from iron in molds and then underwent several finishing processes until the cam lobes and the shaft were in precise orientation with respect to one another so as to facilitate a precision valve control on combustion engines. Many improvements and different methods have since been realized. For example, continuous attempts to improve automobile fuel consumptions have become a major social concern so as to preserve fuel reservoirs and protect the environment. As a result, a lightening of automobile parts including camshafts has received keen attention.
[0024] Methods of making camshafts for internal combustion engines from hollow tubular shafts are known in the prior art. For example, U.S. Pat. No.
4,293,995 to Jordan discloses a method of making a camshaft for reciprocal piston engines whereby cams having irregularly shaped apertures are arranged on a hollow shaft and secured in a die. The hollow shaft is then widened by means of a rubber rod which substantially corresponds to the inner diameter of the hollow shaft. The rubber rod is compressed from both ends to cause the body of the rod to expand. The hollow tubular shaft is widened to such an extent that the outside wall of the shaft surrounded by the cam reaches into the irregular inner form of the cam producing a tight, secure, fit. In addition, the patent also discloses the use of hydraulic or electro-hydraulic expansion of the shaft.
100251 Japanese Patent Application No. 46-21299 relating to a method for shaping a camshaft discloses a structure in which a shaft tube and a cam, a journal or the like are jointed by setting the cam, the journal or a shaft head in a split mold, by inserting the shaft tube into the axial hole of the journal and by radially expanding the shaft tube through a die or mandrel.
[0026] Japanese Patent Application No. 5-288014 relating to a camshaft discloses a structure in which the camshaft is assembled from a camshaft made of a sintered alloy and a camshaft made of a steel pipe by constructing an inner piece and a hollow shaft Doc. No.705561 CA Patent of an easily expandable steel and by expanding and jointing them with a high-pressure fluid and a mandrel.
100271 Japanese Patent Application No. 53-102861 relating to a method for jointing a ring to a hollow shaft discloses a structure in which the cam on the hollow shaft is fixed in the tuning direction and in the axial direction by forming paddings on the two sides of the ring of the hollow shaft.
[0028] Japanese Patent Application No. 8-158817 relating to a method for manufacturing an assembly-type camshaft discloses a structure in which a projection of a shaft is registered with a groove of a cam or cam lobe and is bulged and press-fitted in the groove by expanding the shaft.
[0029] Other methods include to drive a ball or mandrel of larger diameter than the interior diameter of the tubular shaft to expand the same into engagement with the interior apertures in the lobes. Such methods require close tolerances in the lobes, tube thickness and mandrel or ball.
[0030) U.S. Pat. No. 2,892,254 to Garvin discloses a method of making a camshaft wherein the cam lobes are formed from the tubular shaft by the application of internal pressure to the tubular shaft while the shaft is contained in a die having cavities conforming to the shape of the lobes. The cam lobes are formed one at a time in sequence in the die by the application of hydraulic pressure within the tubular shaft such that the shaft expands into the cavities of the die thereby forming the cam lobes.
[0031] Associated problems with manufacturing camshafts from hollow tubular shafts by using hydraulic pressure to expand the tubular shaft outwardly include expensive and elaborate piston cylinder arrangements that are utilized to create sufficient hydraulic pressure for the expansion of the tubular shaft. Furthermore, the manufacturing of hollow camshafts via hydroforming requires the use of high internal pressures and as a result all systems associated with hydroforming such as expensive dies, end sealing and feeding, large press tonnage, and high cost tooling.
100231 In the history of the internal combustion engine, camshafts were cast from iron in molds and then underwent several finishing processes until the cam lobes and the shaft were in precise orientation with respect to one another so as to facilitate a precision valve control on combustion engines. Many improvements and different methods have since been realized. For example, continuous attempts to improve automobile fuel consumptions have become a major social concern so as to preserve fuel reservoirs and protect the environment. As a result, a lightening of automobile parts including camshafts has received keen attention.
[0024] Methods of making camshafts for internal combustion engines from hollow tubular shafts are known in the prior art. For example, U.S. Pat. No.
4,293,995 to Jordan discloses a method of making a camshaft for reciprocal piston engines whereby cams having irregularly shaped apertures are arranged on a hollow shaft and secured in a die. The hollow shaft is then widened by means of a rubber rod which substantially corresponds to the inner diameter of the hollow shaft. The rubber rod is compressed from both ends to cause the body of the rod to expand. The hollow tubular shaft is widened to such an extent that the outside wall of the shaft surrounded by the cam reaches into the irregular inner form of the cam producing a tight, secure, fit. In addition, the patent also discloses the use of hydraulic or electro-hydraulic expansion of the shaft.
100251 Japanese Patent Application No. 46-21299 relating to a method for shaping a camshaft discloses a structure in which a shaft tube and a cam, a journal or the like are jointed by setting the cam, the journal or a shaft head in a split mold, by inserting the shaft tube into the axial hole of the journal and by radially expanding the shaft tube through a die or mandrel.
[0026] Japanese Patent Application No. 5-288014 relating to a camshaft discloses a structure in which the camshaft is assembled from a camshaft made of a sintered alloy and a camshaft made of a steel pipe by constructing an inner piece and a hollow shaft Doc. No.705561 CA Patent of an easily expandable steel and by expanding and jointing them with a high-pressure fluid and a mandrel.
100271 Japanese Patent Application No. 53-102861 relating to a method for jointing a ring to a hollow shaft discloses a structure in which the cam on the hollow shaft is fixed in the tuning direction and in the axial direction by forming paddings on the two sides of the ring of the hollow shaft.
[0028] Japanese Patent Application No. 8-158817 relating to a method for manufacturing an assembly-type camshaft discloses a structure in which a projection of a shaft is registered with a groove of a cam or cam lobe and is bulged and press-fitted in the groove by expanding the shaft.
[0029] Other methods include to drive a ball or mandrel of larger diameter than the interior diameter of the tubular shaft to expand the same into engagement with the interior apertures in the lobes. Such methods require close tolerances in the lobes, tube thickness and mandrel or ball.
[0030) U.S. Pat. No. 2,892,254 to Garvin discloses a method of making a camshaft wherein the cam lobes are formed from the tubular shaft by the application of internal pressure to the tubular shaft while the shaft is contained in a die having cavities conforming to the shape of the lobes. The cam lobes are formed one at a time in sequence in the die by the application of hydraulic pressure within the tubular shaft such that the shaft expands into the cavities of the die thereby forming the cam lobes.
[0031] Associated problems with manufacturing camshafts from hollow tubular shafts by using hydraulic pressure to expand the tubular shaft outwardly include expensive and elaborate piston cylinder arrangements that are utilized to create sufficient hydraulic pressure for the expansion of the tubular shaft. Furthermore, the manufacturing of hollow camshafts via hydroforming requires the use of high internal pressures and as a result all systems associated with hydroforming such as expensive dies, end sealing and feeding, large press tonnage, and high cost tooling.
Doc. No.705S61 CA Patent [0032] It is desirable to provide a light assembled hollow camshaft for engines having good mechanical durability and maintainability, and a production method therefore.
[0033] It is desirable to provide a more cost effective method of manufacturing a camshaft having a hollow shaft.
[0034] It is further desirable to provide an electromagnetic (EM) coil capable of generating sufficient pressure to deform the tubular blank onto the camshaft lobes instead of using hydroforming fluid pressure.
Summary Of The Invention [0035] An object of the present invention is to overcome the problems delineated hereinabove. In accordance with this object, the present invention provides an apparatus for forming a metal work piece into a structural member comprising a hydroforming mold assembly for hydroforming a metal blank into a hydroformed member, said hydroforming mold assembly comprising a trimming/piercing assembly comprising an electromagnetic coil and an electromagnetic driver for trimming/piercing the_hydroformed member into the structural member, said electromagnetic coil and said electromagnetic driver being arranged opposite to each other.
[0036] In accordance with another aspect of the invention, the electromagnetic driver further comprises an electromagnetic top plate and a trimming/piercing tool.
The electromagnetic top plate is arranged opposite to the electromagnetic coil and the trimming/piercing tool is arranged opposite to the workpiece.
[0037] In accordance with yet another aspect of the invention, the apparatus further comprises an electric discharge circuit for discharging the electric discharge circuit so as to trigger the electromagnetic driver. The electric discharge circuit is connected to the electromagnetic coil.
[0033] It is desirable to provide a more cost effective method of manufacturing a camshaft having a hollow shaft.
[0034] It is further desirable to provide an electromagnetic (EM) coil capable of generating sufficient pressure to deform the tubular blank onto the camshaft lobes instead of using hydroforming fluid pressure.
Summary Of The Invention [0035] An object of the present invention is to overcome the problems delineated hereinabove. In accordance with this object, the present invention provides an apparatus for forming a metal work piece into a structural member comprising a hydroforming mold assembly for hydroforming a metal blank into a hydroformed member, said hydroforming mold assembly comprising a trimming/piercing assembly comprising an electromagnetic coil and an electromagnetic driver for trimming/piercing the_hydroformed member into the structural member, said electromagnetic coil and said electromagnetic driver being arranged opposite to each other.
[0036] In accordance with another aspect of the invention, the electromagnetic driver further comprises an electromagnetic top plate and a trimming/piercing tool.
The electromagnetic top plate is arranged opposite to the electromagnetic coil and the trimming/piercing tool is arranged opposite to the workpiece.
[0037] In accordance with yet another aspect of the invention, the apparatus further comprises an electric discharge circuit for discharging the electric discharge circuit so as to trigger the electromagnetic driver. The electric discharge circuit is connected to the electromagnetic coil.
Doc. No. 705561 CA Patent [0038] In accordance with a further aspect of the invention, the apparatus further comprises a control circuit for timing the electrical discharge circuit. The control circuit is connected to the electric discharge circuit.
[0039] In accordance with a further embodiment of the invention, the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member to form the structural member.
[0040] In accordance with the invention there is further provided, a method of forming a metal blank into a structural member of a predetermined shape comprising the following steps of placing the metal blank in a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank to form a hydroformed member; and applying electromagnetic energy for at least one of trimming and piercing the hydroformed member while the hydroformed member remains in the hydroforming mold.
[0041] In accordance with another aspect of the invention, the step of applying electromagnetic energy includes the steps of delivering an electric current to an electromagnetic coil and inducing a current in an electromagnetic driver, said electromagnetic driver including a trimming/piercing tool, and wherein said structural member is trimmed/pierced by the trimming/piercing tool as a result of the repulsive forces generated by the induced current in the driver.
[0042] In accordance with a further aspect of the invention, the driver is formed by disposing an electromagnetic top plate on the driver opposite to the electromagnetic coil.
[0043] In accordance with yet another aspect of the invention, the hydroforming mold comprises more than one electromagnetic trimming/piercing assemblies.
Furthermore, the method comprises the additional step of controlling the more than one electromagnetic trimming/piercing assemblies by a control circuit for controlling the discharge circuit.
[0039] In accordance with a further embodiment of the invention, the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member to form the structural member.
[0040] In accordance with the invention there is further provided, a method of forming a metal blank into a structural member of a predetermined shape comprising the following steps of placing the metal blank in a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank to form a hydroformed member; and applying electromagnetic energy for at least one of trimming and piercing the hydroformed member while the hydroformed member remains in the hydroforming mold.
[0041] In accordance with another aspect of the invention, the step of applying electromagnetic energy includes the steps of delivering an electric current to an electromagnetic coil and inducing a current in an electromagnetic driver, said electromagnetic driver including a trimming/piercing tool, and wherein said structural member is trimmed/pierced by the trimming/piercing tool as a result of the repulsive forces generated by the induced current in the driver.
[0042] In accordance with a further aspect of the invention, the driver is formed by disposing an electromagnetic top plate on the driver opposite to the electromagnetic coil.
[0043] In accordance with yet another aspect of the invention, the hydroforming mold comprises more than one electromagnetic trimming/piercing assemblies.
Furthermore, the method comprises the additional step of controlling the more than one electromagnetic trimming/piercing assemblies by a control circuit for controlling the discharge circuit.
Doc. No.705561 CA Patent [0044] In accordance with one embodiment of the invention, the control circuit times an electrical discharge such that all discharges are occurring in a predetermined sequence.
[0045] In accordance with another embodiment of the invention, the control circuit times an electrical discharge such that all discharges are substantially simultaneous.
[0046] In accordance with another aspect of the invention, the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member, and in accordance with yet another aspect of the invention, as the trimming/piercing tool is a punch tool for providing notches or cut-out sections in the hydroformed member.
[0047] Furthermore, in accordance with the instant invention there is provided, a method of forming a structural member of a predetermined shape comprising the following steps of placing a metal blank into a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly; hydroforming the metal blank into a hydroformed member; energizing an electric discharge circuit for creating an electromagnetic force sufficient for driving an electromagnetic driver; and discharging the electric discharge circuit for driving the electromagnetic driver toward the hydroformed member, said electromagnetic driver comprising a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape.
[0048] In accordance with another aspect of the invention, the structural member is for use as a structural member in automotive applications.
[0049] This and other objects of the invention can be more fully appreciated from the following detailed description of the preferred embodiments.
[0045] In accordance with another embodiment of the invention, the control circuit times an electrical discharge such that all discharges are substantially simultaneous.
[0046] In accordance with another aspect of the invention, the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member, and in accordance with yet another aspect of the invention, as the trimming/piercing tool is a punch tool for providing notches or cut-out sections in the hydroformed member.
[0047] Furthermore, in accordance with the instant invention there is provided, a method of forming a structural member of a predetermined shape comprising the following steps of placing a metal blank into a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly; hydroforming the metal blank into a hydroformed member; energizing an electric discharge circuit for creating an electromagnetic force sufficient for driving an electromagnetic driver; and discharging the electric discharge circuit for driving the electromagnetic driver toward the hydroformed member, said electromagnetic driver comprising a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape.
[0048] In accordance with another aspect of the invention, the structural member is for use as a structural member in automotive applications.
[0049] This and other objects of the invention can be more fully appreciated from the following detailed description of the preferred embodiments.
Doc. No.70SS61 CA Patent Brief Description of the Drawings [0050] Exemplary embodiments of the invention will now be described in conjunction with the following drawings wherein like numerals represent like elements, and wherein:
100511 Fig. 1 a is a schematic presentation of a tubular blank for use in hydroforming;
100521 Fig. lb is a schematic presentation of a hydroformed member;
[0053] Fig. 1 c is a schematic presentation of a trimmed and pierced hydroformed member in accordance with an embodiment of the instant invention;
[0054] Fig. 2 shows a schematic presentation of a portion of a hydroforming die assembly including an EM trimming/piercing assembly in accordance with the instant invention;
[0055] Fig. 3 shows a schematic top view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0056] Fig. 4 shows a schematic side view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
and [0057] Fig. 5 shows a schematic presentation of a portion of a hydroforming die assembly including an EM trimming/piercing assembly in accordance with the instant invention after discharging the electric discharge circuit.
[0058] Fig.6 shows a schematic cross-sectional view of a portion of an apparatus in accordance with the invention;
[0059] Figs. 7a-c show schematic cross-sectional end views of a variety of differently shaped hollow tube members;
Doc. No.705561 CA Patent [0060] Fig. 8 shows a schematic top view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0061] Fig. 9 shows a schematic side view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0062] Fig. 10 shows a schematic cross-sectional view of an apparatus in accordance with the instant invention;
[0063] Fig. 11 shows a schematic cross-sectional view of the apparatus depicted in Fig. 5 in operation, after the electric discharge switch is closed;
[0064] Fig. 12 shows an oblique view of a formed hollow tubular member after it has been removed from the apparatus depicted in Fig. 11; and [0065] Figs. 13a j show a schematic presentation depicting various examples of shapes available with metal forming, such as a flanged and dished head (Fig.
13a), a cylindrical shell (Fig. 13b), a stepped cover (Fig. 13c), a re-entrant flared shape (Fig.
13d), a venturi shape (Fig. 13e), a hemispherical shape (Fig. 13f), a flanged cover (Fig. 13g), a cone shape (Fig. 13h), and a parabolic nose shape (Fig. 13j).
[0066] Fig. 14 shows a schematic cross-sectional view in accordance with an embodiment of the invention wherein the tool mandrel is designed to be a two-part mandrel;
[0067] Fig. 15 shows an oblique view of a camshaft assembly in accordance with the invention having a hollow shaft and a plurality of cam lobe and journal elements affixed thereon;
[0068] Fig. 16 shows an exploded view illustrating various elements of a camshaft assembly in accordance with one embodiment of the invention;
[0069] Fig. 17 shows an oblique view of a tool used for pre-positioning various elements before locking them on a camshaft assembly;
Doc. No.705S61 CA Patent 100701 Fig. 18a shows a schematic cross-sectional view of a portion of a hollow shaft inserted through the openings of cam lobe and/or journal elements and a spacer element disposed between and separating the cam lobe and/or journal elements;
[0071] Fig. 18b shows a schematic cross-sectional view of the assembly depicted in Fig. 4a having an electromagnetic coil placed inside the hollow shaft; and [0072] Fig. 18c shows a schematic cross-sectional view of the assemblies depicted in Figs. 18a and 18b and further illustrating an electric discharge circuit connected thereto.
Detailed Description Of The Preferred Embodiments [0073] In accordance with the present invention, a method and an apparatus are provided which combine the use of hydroforming and the use of electromagnetic energy to form structural members that may be used, for example, in the construction of motor vehicles.
[0074] In general, hydroformed members are formed by placing a tubular blank 102, such as shown in Fig. 1 a, into a cavity of a hydroforming die assembly and providing a high pressure fluid into an interior of the tubular blank 102. The blank 102 is positioned in the cavity and a hydroforming fluid is injected into the blank.
The high pressure fluid expands the wall of the blank102 outwardly into conformity with the surfaces of the cavity of the hydroforming die and thereby forming a hydroformed member 104, such as shown in Fig. lb. Such hydroformed members can be used in many applications, including their use as structural members, such as pillars and side rails for vehicle frame construction, in automotive applications. After the hydroforming operation is finished, the hydroformed member 104 may be further processed, such as by trimming and/or piercing. In accordance with the instant invention, this is advantageously performed while the hydroformed member remains in the cavity of the hydroforming die assembly using an electromagnetic trimming/piercing assembly. Fig. 1 c shows a processed hydroformed member 106 wherein notches or cut out sections 108, 110 are formed in an end portion of the Doc. No.705561 CA Patent hydroformed member 106, and one or more openings 112, 114, 116 are formed through interior wall portions of the hydroformed member 106.
[0075] The method and the apparatus of the instant invention make use of electromagnetic technology to provide a relatively large amount of energy in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this energy can be used to perform useful work, such as applying an energy to stroke hydroform pierce punches for the piercing sequence of the hydroform cycle. If desired, more than one pierce punch may be employed. The electromagnetic energy is delivered simultaneously to all the pierce punches employed and thus obviates typical hydraulic problems of pressure loss as soon as the oil begins to flow in prior art hydraulic cylinders. Furthermore, electromagnetic pressure coils can be designed to be much smaller in size than an equivalent hydraulic piercing cylinder and thus will not require as much machining as is required for the mounting of hydraulic pierce cylinders. The method and the apparatus in accordance with the instant invention may be used to pierce and/or trim a hydroformed member in the hydroforming mold subsequently to the hydroforming process as described heretofore.
[0076] Reference is now being made to Fig. 2 showing a schematic presentation of a portion of apparatus 200 in accordance with the instant invention. Apparatus includes a hydroforming die assembly 202 to hydroform workpiece 204. The hydroforming die assembly 202 further includes an electromagnetic trimming/piercing assembly 206 including an insulator 208, an electromagnetic (EM) coi1210, and an electromagnetic driver 212 including an EM top plate 214 and a trimming/piercing tool 216. The EM coi1210 is embedded in the EM trimming/piercing assembly 206 and should be electrically insulated from surrounding metal objects. For this reason, insulator 208 is provided in the EM trimming/piercing assembly 206 in form of a insulating plate. If desired, EM coi1210 can also be covered by an electrically insulating material.
100771 As can be seen from Figs. 3-4, EM coil 210 of the EM trimming/piercing assembly 206 is electrically connected via conductors 308, 310 to an electric discharge Doc. No.70SS61 CA Patent circuit 300 including an electric power source 302 and a high current rapid discharge switch 304. Discharge switch 304 is connected to a control circuit 306 to control the discharge and hence the operation of the EM trimming/piercing assembly 206.
[0078] In case a plurality of trimming/piercing operations are to be performed on a workpiece, they can be performed simultaneous or in a predetermined sequence.
If the trimming/piercing operations are to be performed in a simultaneous manner it is sufficient to provide a single discharge circuit for the plurality of EM
trimming/piercing assemblies. If the trimming/piercing operations are to be performed in a predetermined sequence, each EM trimming/piercing assembly is provided with an electric discharge circuit. An electric current is discharged between each pair of electrodes. A control circuit can time the electrical discharge between the electrodes such that all discharges are simultaneous or in a predetermined sequence.
[0079] The distance between the EM trimming/piercing assembly 206 and the electric discharge circuit 300 can be chosen in dependence upon the particular circumstances of an application. For example, should it be necessary to place the discharge circuit further away from the hydroforming die assembly of the instant invention including an EM trimming/piercing assembly, it can be achieved by selecting conductors 308, of a respective length.
[0080] In operation, a huge pulse of current is forced through the EM coil by rapidly 2o discharging a high voltage capacitor bank using an ignitron or a spark gap as a switch.
This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM
coil. The rapidly changing magnetic field induces a circulating electrical current within the drive plate through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metal drive plate. Because of Lenz's Law, the magnetic fields created within the metal drive plate and EM
coil strongly repel each another driving the drive plate and the attached trimming/piercing tool toward the workpiece. This occurs very quickly, typically tens of microseconds.
[0081] Reference is now being made to Fig. 5 showing a schematic presentation of an activated EM trimming/piercing assembly 206 upon discharging the electric discharge Doc.1Vo.705S61 CA Patent circuit. The EM pressure coil 210 is used to generate a magnetic field which repels drive plate 212 having an EM top plate 214. The trimming/piercing too1216 is attached to the drive plate 212. Thus, if the discharge circuit is discharged, the drive plate 212 is driven through the EM coil 210 and the EM top plate 214. The driver 212 in turn advances the trimming/piercing too1216. In the embodiment depicted in Fig.
5, the trimming/piercing tool 216 is a punch tool to provide an opening 502 through an interior wall portion of workpiece 204 after it has been hydroformed while remaining in the hydroforming die assembly 202. Alternatively, other trimming/piercing tools may be employed to provide predetermined notches or cut-out sections or openings in the hydroformed workpiece.
[0082] Advantageously, in accordance with the present invention, the combination of a hydroforming die with an EM trimming/piercing assembly to trim/pierce a workpiece in a hydroforming die subsequently to the hydroforming process obviates the difficulties encountered with conventional hydraulic cylinders of various diameters in their attempt to move simultaneously. In order to achieve this, hydraulic cylinders require a tremendous amount of oil volume and pressure which makes such systems very costly: Furthermore, once one of the hydraulic cylinders performs a trimming/piercing operation, a pressure loss is observed in the workpiece.
However, this pressure is needed in the workpiece so that the other trimming/piercing assemblies can be successful. An EM trimming/piercing assembly in accordance with the instant invention can advance trimming/piercing tools fast and substantially simultaneous.
[0083] Moreover, in accordance with another advantage of the instant invention, an EM trimming/piercing assernbly is smaller than a conventional hydraulic cylinder assembly and thus packages easily in the hydroforming die. Furthermore, EM
pressure coils are easier to mount into the die and thus eliminating costs.
[0084] In accordance with another embodiment of the present invention, a tubular member is formed employing an electromagnetic (EM) forming method and apparatus. More particularly, an external electromagnetic pressure coil is employed to generate a magnetic field and hence pressure which in turn repels a tubular member at Doc. No.705561 CA Patent a rapid speed and forces the tubular member to conform to the shape of an inner mandrel provided in a bore of the tubular member.
[0085] EM Technology can be used to provide a relatively large amounts of energy in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this energy can be used to perform useful work such as metal forming. The energy is applied very rapidly which causes extremely high strain rates in the material and thus allows a level of formability which would otherwise be unattainable.
[0086] Fig. 6 shows a schematic cross-sectional view of a portion of an apparatus 1100 in accordance with the invention. An inner mandrel 1102 is placed inside a bore 1106 about an axis 1104 of a hollow tubular member 1108. A multi-turn coil 1110 is placed about an outer surface of the hollow tubular member 1108. The inner mandrel 1102 has a forming surface 1112. In operation, an electric current rapidly discharges through the multi-turn coil 1110 resulting in a pulsed magnetic force which causes a rapid movement of the hollow tubular member 1108 towards the forming surface 1112 of the inner mandrel 1102, and thus the hollow tubular member 1108 assumes the shape of the forming surface of the inner mandrel.
[0087] It will be appreciated that the shape of the inner mandrel which defines the shape of the hollow tubular member as shown in Fig. 6 is exemplary and inner mandrels with a variety of predetermined forming surfaces may be used in accordance with the instant invention. Figs. 7a-c show schematic cross-sectional end views of a variety of differently shaped hollow tube members, viz. Fig. 7a shows a circular cross-sectional configuration, Fig. 7b shows a rectangular cross-sectional configuration, and Fig. 7c shows a cross-shaped cross-sectional configuration.
[0088] Figs. 8-9 present a schematic top and side view of an electromagnetic coil 1301 connected to an electric discharge circuit 1300 in accordance with an embodiment of the instant invention. EM coil 1301 is electrically connected via conductors 1308, 1310 to an electric discharge circuit 1300 including an electric power source 1302 and a high current rapid discharge switch 1304. Discharge switch Doc. No.70S561 CA Patent 1304 is connected to a control circuit 1306 to control the discharge and hence the operation of an EM forming apparatus in accordance with the invention as will be explained in more detail hereinafter.
[0089] In case a plurality of forming operations are to be performed on a workpiece, such as a hollow tubular member, they can be performed simultaneous or in a predetermined sequence. If the forming operations are to be performed in a simultaneous manner it is sufficient to provide a single discharge circuit for the plurality of EM forming assemblies. If the forming operations are to be performed in a predetermined sequence, each EM forming assembly is provided with an electric discharge circuit. An electric current is discharged between each pair of electrodes. A
control circuit can time the electrical discharge between the electrodes such that all discharges are simultaneous or in a predetermined- sequence.
[0090] The distance between an EM forming assembly and the electric discharge circuit 1300 can be chosen in dependence upon the particular circumstances of an application. For example, should it be necessary to place the discharge circuit further away from an EM forming assembly in accordance with the instant invention, it can.
be achieved by selecting conductors 1308, 1310 of a respective length.
[0091] In operation, a large pulse of current is forced through EM coil 1301 by rapidly discharging a high voltage capacitor bank using, for example, an ignitron or a spark gap as a switch. This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM coil. The rapidly changing magnetic field induces a circulating electrical current within the metallic tubular member through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metallic tubular member. Because of Lenz's Law, the magnetic fields created within the metallic tubular member and the EM coil strongly repel each another driving the metallic tubular member toward the tool mandrel. This occurs very quickly, typically in the range of tens of microseconds.
[0092] Reference is now being made to Fig. 10 showing a schematic cross-sectional view of an apparatus 1500 in accordance with the instant invention comprising an Doc. No.705561 CA Patent inner mandrel 1502 having a forming surface 1504. The inner mandrel 1502 is provided inside a passage of a hollow tubular member 1506. Tubular member 1506 is surrounded by an electromagnetic (EM) coil assembly 1508. The EM coil assembly 1508 comprises an EM coil 1510 embedded within a space 1512 of a supporting member 1514. Preferably, supporting member 1514 is made from a non-metallic material. Furthermore, the EM coil 1510 should be electrically insulated from any surrounding metal objects, including the hollow tubular member 1506. For this reason, the EM coil 1510 is covered with an electrically insulating material.
Alternatively, space 1512 may be filled with an electrically insulating material.
100931 As can be seen from Fig. 10, EM coil 1510 is electrically connected to an electric discharge circuit 1516 including a capacitor 1518 and a high current rapid discharge switch 1520 which is controlled by control circuit 1522. The operation of the discharge circuit was explained in more detail heretofore.
[0094] Having regard now to Fig. 11, in operation, the discharge switch 1520 is closed in response to a signal from control circuit 1522, thereby rapidly discharging an electric current through EM coil 1510. As a result of the discharge of the electric current through the coil, a pulsed magnetic force is produced which causes a rapid movement of the hollow tubular member 1506 away from the EM coil 1510 and toward mandrel 1502. The hollow tubular member 1506 is pressed against the forming surface 1504 of the mandrel 1502 and thus complements the shape of the mandrel, as can be seen from Fig. 11, to yield a formed tubular member 1524.
[0095] Fig. 12 presents an oblique view of a formed hollow tubular metal member after it has been removed from the forming apparatus and the mandrel has been removed from the inside of the formed tubular member.
[0096] The specific shape of the formed tubular member as shown in Fig. 12 is only one example in accordance with the invention. A person of skill in the art appreciates that a plurality of other shapes can be achieved in accordance with the method and apparatus of the instant invention. Turning now to Figs. 13a j, a schematic presentation is shown depicting various examples of shapes available with metal Doc. No.70S561 CA Patent forming, such as a flanged and dished head (Fig. 13a), a cylindrical shell (Fig. 13b), a stepped cover (Fig. 13c), a re-entrant flared shape (Fig. 13d), a venturi shape (Fig.
13e), a hemispherical shape (Fig. 13f), a flanged cover (Fig. 13g), a cone shape (Fig.
13h), and a parabolic nose shape (Fig. 13j).
[0097] In accordance with the embodiment presented in Figs. 11 and 12, the EM
coil surrounds the entire circumference of the hollow tubular member to be formed.
However, in accordance with another embodiment of the invention, the EM coil only covers a portion of the hollow tubular member in an axial direction.
[0098] Furthermore, in accordance with yet another embodiment of the instant invention, the forming of the tubular member can be accomplished in a plurality of stages. If the workpiece or tubular member remains in the same apparatus, a control circuit can be used to time the electrical discharge of a plurality of discharge circuits used in the plurality of forming stages.
100991 In accordance with yet another embodiment of the instant invention, the tool mandrel is designed to be a two-part mandrel having a first mandrel member 902 and a second mandrel member 904, as depicted in Fig. 14. Such a mandrel design is advantageously used where a formed tubular member 1906 includes a relatively narrow passage 1908 along an axial extent of the tubular member between a first relatively wider passage 1910 and a second relatively wider passage 1912. The relatively narrow passage 1908 would prevent the mandrel from being removed from the formed tubular member 1906. However, if a releasable two-part mandrel is employed, the first and second mandrel members 1902, 1904 are released from one another and then they can be removed from either side of the formed tubular member, as indicated by arrows A and B of Fig. 14, respectively.
[00100) If desired, a multi-part tool mandrel can be employed to facilitate the removal of the tool mandrel from within a formed tubular member of a more complicated structure. In a similar manner as described above, a plurality of mandrel members are released from one another and are then individually removed from within the formed tubular member.
Doc. No.70S561 CA Patent [00101] In accordance with another embodiment of the present invention, a camshaft is provided having a hollow shaft as well as a method of manufacturing said camshaft.
[00102] Turning now to Fig. 15, a camshaft assembly 2100 is shown having a hollow shaft 2102 with a plurality of cam lobe elements 2104, 2106, 2108, 2110, 2112, 2114, 2116 and journal element 2118 affixed thereon. Additional elements, such as gears, eccentrics or sprockets, could also be included if desired. The cam lobe and journal elements are longitudinally spaced and the cam elements are angularly oriented in predetermined positions, for example for actuating valve gears in an internal combustion engine. A cam timing gear or sprocket (not shown) can be attached to one end of the camshaft 2102 for operably connecting the camshaft assembly 2100 to the timing apparatus of an engine (not showri).
[00103] The shaft 2102 is essentially a cylindrical elongate tubular member which can be formed by drilling out the center of a regular forged or cast camshaft or via a welded assembly. Alternatively, it can be formed from an ordinary steel, cold extruded to a predetermined inside and outside diameter and cut to a predetermined length.
[00104] Fig. 16 shows an exploded view illustrating various elements of the camshaft assembly 2202. Each cam lobe element 2204, 2206, 2208, 2210 is a non-cylindrical disc having an opening 2210, 2212, 2214, 2216, respectively, for receiving the hollow shaft 2218 therethrough. Each journal element 2220, 2224 is an essentially cylindrical disc having an axial opening 2226, 2228, respectively, for receiving the hollow shaft 2218 therethrough.
[00105] The openings 2210, 2212, 2214, 2216, 2226, 2228 have a diameter that is slightly larger than the outer diameter of the hollow shaft 2218. The shape of the openings may be circular or slightly non-circular. Fig. 16 depicts the openings as having a slightly non-circular hexagonal shape. Alternatively, other slightly non-circular polygonal shapes may be chosen. Advantageously, the slightly non-circular Doc. No.705561 CA Patent shape of the openings provides a better torsional retention of the cam lobes and journal elements and/or other elements on the shaft.
[00106] The individual cam lobe, journal, and/or other elements are inserted into a tool so as to pre-position them in their predetermined final orientations with their openings aligned for insertion of the tube or hollow shaft. The elements are securely held in a tool in a predetermined longitudinally spaced apart relationship to one another. Furthermore, the cam lobe elements are securely held in a predetermined rotationally or angularly oriented relationship to one another as they are secured in the tool. This is shown in more detail in Fig. 17, illustrating a tool 2300 having a base 2302 and a longitudinal recess 2304. The journal elements 2316, 2318 and cam lobe elements 2320, 2322, 2324, 2326, 2328 are provided in recess 2304. The elements are pre-positioned by a plurality of supporting and positioning elements 2306 a-g and separated by a plurality of spacer elements 2308a-g, all of which are retained in the tool between walls 2310 and 2311. A cover 2312 having fixing elements 2314a-c (only a few of which are denoted by reference numeral for clarity reasons) is provided to maintain the elements in their positions with their openings in axial alignment for insertion of hollow shaft or tube 2330.
[00107] Once the hollow shaft as well as the cam lobe, journal and/or other elements are pre-positioned in the tool, an electromagnetic coil is inserted in the hollow shaft. In accordance with the instant invention, electromagnetic (EM) technology can be used to provide large amounts of pressure in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this pressure can be used to perform useful work such as is required in this application to mechanically join the tubular blank to the cam lobe elements, journal elements, and/or other elements. Advantageously, EM
technology overcomes the disadvantages of other camshaft forming methods by having a very short cycle time and by obviating the complex technical features related to hydro/fluid forming as mentioned above.
[00108] Turning now to Figs. 18a and 18b, more detailed schematic cross-sectional views are presented, illustrating the method in accordance with the instant Doc. No.70S561 CA Patent invention. Fig. 18a shows a cross-sectional view of a portion of a hollow shaft 2402 inserted through the openings of cam lobe and/or journal elements 2404, 2406 and a spacer element 2408 disposed between and separating the cam lobe and/or journal elements 2404, 2406. All elements are provided with their openings in axial alignment with axis A. of hollow shaft 2402. The cam lobe and/or journal elements have openings of a diameter that is slightly larger than the outer diameter of the hollow shaft so as to fit closely on the hollow shaft. Spacer element 2408 is designed so as to have a clearance S to the outer diameter of the hollow shaft to allow for an expansion of the tube in the areas between the cam lobe elements, journal elements and/or other elements of the camshaft assembly in accordance with the invention. As can be seen from Fig. 18b, an electromagnetic coi12410 is placed inside the hollow shaft. EM pressure coi12410 is used to generate a magnetic field (pressure) which repels the hollow shaft or tube at a rapid speed so as to join the hollow shaft or tube to the plurality of cam lobe elements, journal elements and/or other elements via mechanical lock.
[00109] In operation, a large pulse of current is forced through EM coil 2410 by rapidly discharging a high voltage capacitor bank using, for example, an ignitron or a spark gap as a switch. This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM coil. The rapidly changing magnetic field induces a circulating electrical current within the metallic hollow shaft or tube through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metallic hollow shaft or tube. Because of Lenz's Law, the magnetic fields created within the metallic hollow shaft or tube and the EM coil strongly repel each another driving the metallic hollow shaft or tube toward the plurality of cam lobe elements, journal elements, spacer elements and/or other elements provided in the tool.
This occurs very quickly, typically in the range of tens of microseconds.
[00110] The electromagnetic pressure causes the hollow shaft or tube to expand diametrically and thus forming a mechanical bond between the hollow shaft or tube and the various elements provided thereon. The diametrical expansion of the hollow shaft or tube forces the outer surface of the hollow shaft or tube into a mechanical locking relationship. As shown in Fig. 18b, the portions of the hollow shaft or tube Doc. No. 705561 CA Patent adjacent to the spacer element are diametrically expanded beyond the opening diameter by a predetermined difference 6e, so as to positively lock the various elements in their predetermined longitudinal relationship.
[00111] Once all of the elements are affixed to the hollow shaft or tube, the electromagnetic coil is removed from the hollow shaft or tube and the final camshaft assembly is removed from the fixing tool. Finally, the wearing surfaces of the various elements of the camshaft assembly are ground to the desired surface finish and dimensions.
[00112] Having regard now to Fig.l 8c, a schematic cross-sectional view of a portion of expanded hollow shaft 2402 is shown, and further illustrating an electric discharge circuit 2412 connected thereto. The electric discharge circuit 2412 includes a capacitor 2414 and a high current rapid discharge switch 2416 which is controlled by control circuit 2418. As shown, in Fig. 18c, in operation, the discharge switch 2416 is closed in response to a signal from control circuit 2418, thereby rapidly discharging an electric current through EM coil 2410 and thus diametrically expanding the hollow shaft or tube 2402.
[00113] The above described embodiments of the invention are intended to be examples of the present invention and numerous modifications, variations, and adaptations may be made to the particular embodiments of the invention without departing from the spirit and scope of the invention, which is defined in the claims.
100511 Fig. 1 a is a schematic presentation of a tubular blank for use in hydroforming;
100521 Fig. lb is a schematic presentation of a hydroformed member;
[0053] Fig. 1 c is a schematic presentation of a trimmed and pierced hydroformed member in accordance with an embodiment of the instant invention;
[0054] Fig. 2 shows a schematic presentation of a portion of a hydroforming die assembly including an EM trimming/piercing assembly in accordance with the instant invention;
[0055] Fig. 3 shows a schematic top view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0056] Fig. 4 shows a schematic side view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
and [0057] Fig. 5 shows a schematic presentation of a portion of a hydroforming die assembly including an EM trimming/piercing assembly in accordance with the instant invention after discharging the electric discharge circuit.
[0058] Fig.6 shows a schematic cross-sectional view of a portion of an apparatus in accordance with the invention;
[0059] Figs. 7a-c show schematic cross-sectional end views of a variety of differently shaped hollow tube members;
Doc. No.705561 CA Patent [0060] Fig. 8 shows a schematic top view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0061] Fig. 9 shows a schematic side view of an electromagnetic coil connected to an electric discharge circuit in accordance with an embodiment of the invention;
[0062] Fig. 10 shows a schematic cross-sectional view of an apparatus in accordance with the instant invention;
[0063] Fig. 11 shows a schematic cross-sectional view of the apparatus depicted in Fig. 5 in operation, after the electric discharge switch is closed;
[0064] Fig. 12 shows an oblique view of a formed hollow tubular member after it has been removed from the apparatus depicted in Fig. 11; and [0065] Figs. 13a j show a schematic presentation depicting various examples of shapes available with metal forming, such as a flanged and dished head (Fig.
13a), a cylindrical shell (Fig. 13b), a stepped cover (Fig. 13c), a re-entrant flared shape (Fig.
13d), a venturi shape (Fig. 13e), a hemispherical shape (Fig. 13f), a flanged cover (Fig. 13g), a cone shape (Fig. 13h), and a parabolic nose shape (Fig. 13j).
[0066] Fig. 14 shows a schematic cross-sectional view in accordance with an embodiment of the invention wherein the tool mandrel is designed to be a two-part mandrel;
[0067] Fig. 15 shows an oblique view of a camshaft assembly in accordance with the invention having a hollow shaft and a plurality of cam lobe and journal elements affixed thereon;
[0068] Fig. 16 shows an exploded view illustrating various elements of a camshaft assembly in accordance with one embodiment of the invention;
[0069] Fig. 17 shows an oblique view of a tool used for pre-positioning various elements before locking them on a camshaft assembly;
Doc. No.705S61 CA Patent 100701 Fig. 18a shows a schematic cross-sectional view of a portion of a hollow shaft inserted through the openings of cam lobe and/or journal elements and a spacer element disposed between and separating the cam lobe and/or journal elements;
[0071] Fig. 18b shows a schematic cross-sectional view of the assembly depicted in Fig. 4a having an electromagnetic coil placed inside the hollow shaft; and [0072] Fig. 18c shows a schematic cross-sectional view of the assemblies depicted in Figs. 18a and 18b and further illustrating an electric discharge circuit connected thereto.
Detailed Description Of The Preferred Embodiments [0073] In accordance with the present invention, a method and an apparatus are provided which combine the use of hydroforming and the use of electromagnetic energy to form structural members that may be used, for example, in the construction of motor vehicles.
[0074] In general, hydroformed members are formed by placing a tubular blank 102, such as shown in Fig. 1 a, into a cavity of a hydroforming die assembly and providing a high pressure fluid into an interior of the tubular blank 102. The blank 102 is positioned in the cavity and a hydroforming fluid is injected into the blank.
The high pressure fluid expands the wall of the blank102 outwardly into conformity with the surfaces of the cavity of the hydroforming die and thereby forming a hydroformed member 104, such as shown in Fig. lb. Such hydroformed members can be used in many applications, including their use as structural members, such as pillars and side rails for vehicle frame construction, in automotive applications. After the hydroforming operation is finished, the hydroformed member 104 may be further processed, such as by trimming and/or piercing. In accordance with the instant invention, this is advantageously performed while the hydroformed member remains in the cavity of the hydroforming die assembly using an electromagnetic trimming/piercing assembly. Fig. 1 c shows a processed hydroformed member 106 wherein notches or cut out sections 108, 110 are formed in an end portion of the Doc. No.705561 CA Patent hydroformed member 106, and one or more openings 112, 114, 116 are formed through interior wall portions of the hydroformed member 106.
[0075] The method and the apparatus of the instant invention make use of electromagnetic technology to provide a relatively large amount of energy in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this energy can be used to perform useful work, such as applying an energy to stroke hydroform pierce punches for the piercing sequence of the hydroform cycle. If desired, more than one pierce punch may be employed. The electromagnetic energy is delivered simultaneously to all the pierce punches employed and thus obviates typical hydraulic problems of pressure loss as soon as the oil begins to flow in prior art hydraulic cylinders. Furthermore, electromagnetic pressure coils can be designed to be much smaller in size than an equivalent hydraulic piercing cylinder and thus will not require as much machining as is required for the mounting of hydraulic pierce cylinders. The method and the apparatus in accordance with the instant invention may be used to pierce and/or trim a hydroformed member in the hydroforming mold subsequently to the hydroforming process as described heretofore.
[0076] Reference is now being made to Fig. 2 showing a schematic presentation of a portion of apparatus 200 in accordance with the instant invention. Apparatus includes a hydroforming die assembly 202 to hydroform workpiece 204. The hydroforming die assembly 202 further includes an electromagnetic trimming/piercing assembly 206 including an insulator 208, an electromagnetic (EM) coi1210, and an electromagnetic driver 212 including an EM top plate 214 and a trimming/piercing tool 216. The EM coi1210 is embedded in the EM trimming/piercing assembly 206 and should be electrically insulated from surrounding metal objects. For this reason, insulator 208 is provided in the EM trimming/piercing assembly 206 in form of a insulating plate. If desired, EM coi1210 can also be covered by an electrically insulating material.
100771 As can be seen from Figs. 3-4, EM coil 210 of the EM trimming/piercing assembly 206 is electrically connected via conductors 308, 310 to an electric discharge Doc. No.70SS61 CA Patent circuit 300 including an electric power source 302 and a high current rapid discharge switch 304. Discharge switch 304 is connected to a control circuit 306 to control the discharge and hence the operation of the EM trimming/piercing assembly 206.
[0078] In case a plurality of trimming/piercing operations are to be performed on a workpiece, they can be performed simultaneous or in a predetermined sequence.
If the trimming/piercing operations are to be performed in a simultaneous manner it is sufficient to provide a single discharge circuit for the plurality of EM
trimming/piercing assemblies. If the trimming/piercing operations are to be performed in a predetermined sequence, each EM trimming/piercing assembly is provided with an electric discharge circuit. An electric current is discharged between each pair of electrodes. A control circuit can time the electrical discharge between the electrodes such that all discharges are simultaneous or in a predetermined sequence.
[0079] The distance between the EM trimming/piercing assembly 206 and the electric discharge circuit 300 can be chosen in dependence upon the particular circumstances of an application. For example, should it be necessary to place the discharge circuit further away from the hydroforming die assembly of the instant invention including an EM trimming/piercing assembly, it can be achieved by selecting conductors 308, of a respective length.
[0080] In operation, a huge pulse of current is forced through the EM coil by rapidly 2o discharging a high voltage capacitor bank using an ignitron or a spark gap as a switch.
This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM
coil. The rapidly changing magnetic field induces a circulating electrical current within the drive plate through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metal drive plate. Because of Lenz's Law, the magnetic fields created within the metal drive plate and EM
coil strongly repel each another driving the drive plate and the attached trimming/piercing tool toward the workpiece. This occurs very quickly, typically tens of microseconds.
[0081] Reference is now being made to Fig. 5 showing a schematic presentation of an activated EM trimming/piercing assembly 206 upon discharging the electric discharge Doc.1Vo.705S61 CA Patent circuit. The EM pressure coil 210 is used to generate a magnetic field which repels drive plate 212 having an EM top plate 214. The trimming/piercing too1216 is attached to the drive plate 212. Thus, if the discharge circuit is discharged, the drive plate 212 is driven through the EM coil 210 and the EM top plate 214. The driver 212 in turn advances the trimming/piercing too1216. In the embodiment depicted in Fig.
5, the trimming/piercing tool 216 is a punch tool to provide an opening 502 through an interior wall portion of workpiece 204 after it has been hydroformed while remaining in the hydroforming die assembly 202. Alternatively, other trimming/piercing tools may be employed to provide predetermined notches or cut-out sections or openings in the hydroformed workpiece.
[0082] Advantageously, in accordance with the present invention, the combination of a hydroforming die with an EM trimming/piercing assembly to trim/pierce a workpiece in a hydroforming die subsequently to the hydroforming process obviates the difficulties encountered with conventional hydraulic cylinders of various diameters in their attempt to move simultaneously. In order to achieve this, hydraulic cylinders require a tremendous amount of oil volume and pressure which makes such systems very costly: Furthermore, once one of the hydraulic cylinders performs a trimming/piercing operation, a pressure loss is observed in the workpiece.
However, this pressure is needed in the workpiece so that the other trimming/piercing assemblies can be successful. An EM trimming/piercing assembly in accordance with the instant invention can advance trimming/piercing tools fast and substantially simultaneous.
[0083] Moreover, in accordance with another advantage of the instant invention, an EM trimming/piercing assernbly is smaller than a conventional hydraulic cylinder assembly and thus packages easily in the hydroforming die. Furthermore, EM
pressure coils are easier to mount into the die and thus eliminating costs.
[0084] In accordance with another embodiment of the present invention, a tubular member is formed employing an electromagnetic (EM) forming method and apparatus. More particularly, an external electromagnetic pressure coil is employed to generate a magnetic field and hence pressure which in turn repels a tubular member at Doc. No.705561 CA Patent a rapid speed and forces the tubular member to conform to the shape of an inner mandrel provided in a bore of the tubular member.
[0085] EM Technology can be used to provide a relatively large amounts of energy in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this energy can be used to perform useful work such as metal forming. The energy is applied very rapidly which causes extremely high strain rates in the material and thus allows a level of formability which would otherwise be unattainable.
[0086] Fig. 6 shows a schematic cross-sectional view of a portion of an apparatus 1100 in accordance with the invention. An inner mandrel 1102 is placed inside a bore 1106 about an axis 1104 of a hollow tubular member 1108. A multi-turn coil 1110 is placed about an outer surface of the hollow tubular member 1108. The inner mandrel 1102 has a forming surface 1112. In operation, an electric current rapidly discharges through the multi-turn coil 1110 resulting in a pulsed magnetic force which causes a rapid movement of the hollow tubular member 1108 towards the forming surface 1112 of the inner mandrel 1102, and thus the hollow tubular member 1108 assumes the shape of the forming surface of the inner mandrel.
[0087] It will be appreciated that the shape of the inner mandrel which defines the shape of the hollow tubular member as shown in Fig. 6 is exemplary and inner mandrels with a variety of predetermined forming surfaces may be used in accordance with the instant invention. Figs. 7a-c show schematic cross-sectional end views of a variety of differently shaped hollow tube members, viz. Fig. 7a shows a circular cross-sectional configuration, Fig. 7b shows a rectangular cross-sectional configuration, and Fig. 7c shows a cross-shaped cross-sectional configuration.
[0088] Figs. 8-9 present a schematic top and side view of an electromagnetic coil 1301 connected to an electric discharge circuit 1300 in accordance with an embodiment of the instant invention. EM coil 1301 is electrically connected via conductors 1308, 1310 to an electric discharge circuit 1300 including an electric power source 1302 and a high current rapid discharge switch 1304. Discharge switch Doc. No.70S561 CA Patent 1304 is connected to a control circuit 1306 to control the discharge and hence the operation of an EM forming apparatus in accordance with the invention as will be explained in more detail hereinafter.
[0089] In case a plurality of forming operations are to be performed on a workpiece, such as a hollow tubular member, they can be performed simultaneous or in a predetermined sequence. If the forming operations are to be performed in a simultaneous manner it is sufficient to provide a single discharge circuit for the plurality of EM forming assemblies. If the forming operations are to be performed in a predetermined sequence, each EM forming assembly is provided with an electric discharge circuit. An electric current is discharged between each pair of electrodes. A
control circuit can time the electrical discharge between the electrodes such that all discharges are simultaneous or in a predetermined- sequence.
[0090] The distance between an EM forming assembly and the electric discharge circuit 1300 can be chosen in dependence upon the particular circumstances of an application. For example, should it be necessary to place the discharge circuit further away from an EM forming assembly in accordance with the instant invention, it can.
be achieved by selecting conductors 1308, 1310 of a respective length.
[0091] In operation, a large pulse of current is forced through EM coil 1301 by rapidly discharging a high voltage capacitor bank using, for example, an ignitron or a spark gap as a switch. This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM coil. The rapidly changing magnetic field induces a circulating electrical current within the metallic tubular member through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metallic tubular member. Because of Lenz's Law, the magnetic fields created within the metallic tubular member and the EM coil strongly repel each another driving the metallic tubular member toward the tool mandrel. This occurs very quickly, typically in the range of tens of microseconds.
[0092] Reference is now being made to Fig. 10 showing a schematic cross-sectional view of an apparatus 1500 in accordance with the instant invention comprising an Doc. No.705561 CA Patent inner mandrel 1502 having a forming surface 1504. The inner mandrel 1502 is provided inside a passage of a hollow tubular member 1506. Tubular member 1506 is surrounded by an electromagnetic (EM) coil assembly 1508. The EM coil assembly 1508 comprises an EM coil 1510 embedded within a space 1512 of a supporting member 1514. Preferably, supporting member 1514 is made from a non-metallic material. Furthermore, the EM coil 1510 should be electrically insulated from any surrounding metal objects, including the hollow tubular member 1506. For this reason, the EM coil 1510 is covered with an electrically insulating material.
Alternatively, space 1512 may be filled with an electrically insulating material.
100931 As can be seen from Fig. 10, EM coil 1510 is electrically connected to an electric discharge circuit 1516 including a capacitor 1518 and a high current rapid discharge switch 1520 which is controlled by control circuit 1522. The operation of the discharge circuit was explained in more detail heretofore.
[0094] Having regard now to Fig. 11, in operation, the discharge switch 1520 is closed in response to a signal from control circuit 1522, thereby rapidly discharging an electric current through EM coil 1510. As a result of the discharge of the electric current through the coil, a pulsed magnetic force is produced which causes a rapid movement of the hollow tubular member 1506 away from the EM coil 1510 and toward mandrel 1502. The hollow tubular member 1506 is pressed against the forming surface 1504 of the mandrel 1502 and thus complements the shape of the mandrel, as can be seen from Fig. 11, to yield a formed tubular member 1524.
[0095] Fig. 12 presents an oblique view of a formed hollow tubular metal member after it has been removed from the forming apparatus and the mandrel has been removed from the inside of the formed tubular member.
[0096] The specific shape of the formed tubular member as shown in Fig. 12 is only one example in accordance with the invention. A person of skill in the art appreciates that a plurality of other shapes can be achieved in accordance with the method and apparatus of the instant invention. Turning now to Figs. 13a j, a schematic presentation is shown depicting various examples of shapes available with metal Doc. No.70S561 CA Patent forming, such as a flanged and dished head (Fig. 13a), a cylindrical shell (Fig. 13b), a stepped cover (Fig. 13c), a re-entrant flared shape (Fig. 13d), a venturi shape (Fig.
13e), a hemispherical shape (Fig. 13f), a flanged cover (Fig. 13g), a cone shape (Fig.
13h), and a parabolic nose shape (Fig. 13j).
[0097] In accordance with the embodiment presented in Figs. 11 and 12, the EM
coil surrounds the entire circumference of the hollow tubular member to be formed.
However, in accordance with another embodiment of the invention, the EM coil only covers a portion of the hollow tubular member in an axial direction.
[0098] Furthermore, in accordance with yet another embodiment of the instant invention, the forming of the tubular member can be accomplished in a plurality of stages. If the workpiece or tubular member remains in the same apparatus, a control circuit can be used to time the electrical discharge of a plurality of discharge circuits used in the plurality of forming stages.
100991 In accordance with yet another embodiment of the instant invention, the tool mandrel is designed to be a two-part mandrel having a first mandrel member 902 and a second mandrel member 904, as depicted in Fig. 14. Such a mandrel design is advantageously used where a formed tubular member 1906 includes a relatively narrow passage 1908 along an axial extent of the tubular member between a first relatively wider passage 1910 and a second relatively wider passage 1912. The relatively narrow passage 1908 would prevent the mandrel from being removed from the formed tubular member 1906. However, if a releasable two-part mandrel is employed, the first and second mandrel members 1902, 1904 are released from one another and then they can be removed from either side of the formed tubular member, as indicated by arrows A and B of Fig. 14, respectively.
[00100) If desired, a multi-part tool mandrel can be employed to facilitate the removal of the tool mandrel from within a formed tubular member of a more complicated structure. In a similar manner as described above, a plurality of mandrel members are released from one another and are then individually removed from within the formed tubular member.
Doc. No.70S561 CA Patent [00101] In accordance with another embodiment of the present invention, a camshaft is provided having a hollow shaft as well as a method of manufacturing said camshaft.
[00102] Turning now to Fig. 15, a camshaft assembly 2100 is shown having a hollow shaft 2102 with a plurality of cam lobe elements 2104, 2106, 2108, 2110, 2112, 2114, 2116 and journal element 2118 affixed thereon. Additional elements, such as gears, eccentrics or sprockets, could also be included if desired. The cam lobe and journal elements are longitudinally spaced and the cam elements are angularly oriented in predetermined positions, for example for actuating valve gears in an internal combustion engine. A cam timing gear or sprocket (not shown) can be attached to one end of the camshaft 2102 for operably connecting the camshaft assembly 2100 to the timing apparatus of an engine (not showri).
[00103] The shaft 2102 is essentially a cylindrical elongate tubular member which can be formed by drilling out the center of a regular forged or cast camshaft or via a welded assembly. Alternatively, it can be formed from an ordinary steel, cold extruded to a predetermined inside and outside diameter and cut to a predetermined length.
[00104] Fig. 16 shows an exploded view illustrating various elements of the camshaft assembly 2202. Each cam lobe element 2204, 2206, 2208, 2210 is a non-cylindrical disc having an opening 2210, 2212, 2214, 2216, respectively, for receiving the hollow shaft 2218 therethrough. Each journal element 2220, 2224 is an essentially cylindrical disc having an axial opening 2226, 2228, respectively, for receiving the hollow shaft 2218 therethrough.
[00105] The openings 2210, 2212, 2214, 2216, 2226, 2228 have a diameter that is slightly larger than the outer diameter of the hollow shaft 2218. The shape of the openings may be circular or slightly non-circular. Fig. 16 depicts the openings as having a slightly non-circular hexagonal shape. Alternatively, other slightly non-circular polygonal shapes may be chosen. Advantageously, the slightly non-circular Doc. No.705561 CA Patent shape of the openings provides a better torsional retention of the cam lobes and journal elements and/or other elements on the shaft.
[00106] The individual cam lobe, journal, and/or other elements are inserted into a tool so as to pre-position them in their predetermined final orientations with their openings aligned for insertion of the tube or hollow shaft. The elements are securely held in a tool in a predetermined longitudinally spaced apart relationship to one another. Furthermore, the cam lobe elements are securely held in a predetermined rotationally or angularly oriented relationship to one another as they are secured in the tool. This is shown in more detail in Fig. 17, illustrating a tool 2300 having a base 2302 and a longitudinal recess 2304. The journal elements 2316, 2318 and cam lobe elements 2320, 2322, 2324, 2326, 2328 are provided in recess 2304. The elements are pre-positioned by a plurality of supporting and positioning elements 2306 a-g and separated by a plurality of spacer elements 2308a-g, all of which are retained in the tool between walls 2310 and 2311. A cover 2312 having fixing elements 2314a-c (only a few of which are denoted by reference numeral for clarity reasons) is provided to maintain the elements in their positions with their openings in axial alignment for insertion of hollow shaft or tube 2330.
[00107] Once the hollow shaft as well as the cam lobe, journal and/or other elements are pre-positioned in the tool, an electromagnetic coil is inserted in the hollow shaft. In accordance with the instant invention, electromagnetic (EM) technology can be used to provide large amounts of pressure in an extremely rapid event, for example in the order of approximately tens of microseconds. When harnessed properly, this pressure can be used to perform useful work such as is required in this application to mechanically join the tubular blank to the cam lobe elements, journal elements, and/or other elements. Advantageously, EM
technology overcomes the disadvantages of other camshaft forming methods by having a very short cycle time and by obviating the complex technical features related to hydro/fluid forming as mentioned above.
[00108] Turning now to Figs. 18a and 18b, more detailed schematic cross-sectional views are presented, illustrating the method in accordance with the instant Doc. No.70S561 CA Patent invention. Fig. 18a shows a cross-sectional view of a portion of a hollow shaft 2402 inserted through the openings of cam lobe and/or journal elements 2404, 2406 and a spacer element 2408 disposed between and separating the cam lobe and/or journal elements 2404, 2406. All elements are provided with their openings in axial alignment with axis A. of hollow shaft 2402. The cam lobe and/or journal elements have openings of a diameter that is slightly larger than the outer diameter of the hollow shaft so as to fit closely on the hollow shaft. Spacer element 2408 is designed so as to have a clearance S to the outer diameter of the hollow shaft to allow for an expansion of the tube in the areas between the cam lobe elements, journal elements and/or other elements of the camshaft assembly in accordance with the invention. As can be seen from Fig. 18b, an electromagnetic coi12410 is placed inside the hollow shaft. EM pressure coi12410 is used to generate a magnetic field (pressure) which repels the hollow shaft or tube at a rapid speed so as to join the hollow shaft or tube to the plurality of cam lobe elements, journal elements and/or other elements via mechanical lock.
[00109] In operation, a large pulse of current is forced through EM coil 2410 by rapidly discharging a high voltage capacitor bank using, for example, an ignitron or a spark gap as a switch. This creates a rapidly oscillating, ultrastrong electromagnetic field around the EM coil. The rapidly changing magnetic field induces a circulating electrical current within the metallic hollow shaft or tube through electromagnetic induction, and the induced current creates a corresponding magnetic field around the metallic hollow shaft or tube. Because of Lenz's Law, the magnetic fields created within the metallic hollow shaft or tube and the EM coil strongly repel each another driving the metallic hollow shaft or tube toward the plurality of cam lobe elements, journal elements, spacer elements and/or other elements provided in the tool.
This occurs very quickly, typically in the range of tens of microseconds.
[00110] The electromagnetic pressure causes the hollow shaft or tube to expand diametrically and thus forming a mechanical bond between the hollow shaft or tube and the various elements provided thereon. The diametrical expansion of the hollow shaft or tube forces the outer surface of the hollow shaft or tube into a mechanical locking relationship. As shown in Fig. 18b, the portions of the hollow shaft or tube Doc. No. 705561 CA Patent adjacent to the spacer element are diametrically expanded beyond the opening diameter by a predetermined difference 6e, so as to positively lock the various elements in their predetermined longitudinal relationship.
[00111] Once all of the elements are affixed to the hollow shaft or tube, the electromagnetic coil is removed from the hollow shaft or tube and the final camshaft assembly is removed from the fixing tool. Finally, the wearing surfaces of the various elements of the camshaft assembly are ground to the desired surface finish and dimensions.
[00112] Having regard now to Fig.l 8c, a schematic cross-sectional view of a portion of expanded hollow shaft 2402 is shown, and further illustrating an electric discharge circuit 2412 connected thereto. The electric discharge circuit 2412 includes a capacitor 2414 and a high current rapid discharge switch 2416 which is controlled by control circuit 2418. As shown, in Fig. 18c, in operation, the discharge switch 2416 is closed in response to a signal from control circuit 2418, thereby rapidly discharging an electric current through EM coil 2410 and thus diametrically expanding the hollow shaft or tube 2402.
[00113] The above described embodiments of the invention are intended to be examples of the present invention and numerous modifications, variations, and adaptations may be made to the particular embodiments of the invention without departing from the spirit and scope of the invention, which is defined in the claims.
Claims (69)
1. An apparatus for forming a metal work piece into a structural member comprising:
a hydroforming mold assembly for hydroforming a metal blank into a hydroformed member, said hydroforming mold assembly comprising:
a trimming/piercing assembly comprising an electromagnetic coil and an electromagnetic driver for trimming/piercing the hydroformed member into the structural member, said electromagnetic coil and said electromagnetic driver being arranged opposite to each other.
a hydroforming mold assembly for hydroforming a metal blank into a hydroformed member, said hydroforming mold assembly comprising:
a trimming/piercing assembly comprising an electromagnetic coil and an electromagnetic driver for trimming/piercing the hydroformed member into the structural member, said electromagnetic coil and said electromagnetic driver being arranged opposite to each other.
2. The apparatus as defined in claim 1 wherein said electromagnetic driver further comprises an electromagnetic top plate and a trimming/piercing tool, said electromagnetic top plate being arranged opposite to said electromagnetic coil and said trimming/piercing tool being arranged opposite to said workpiece.
3. The apparatus as defined in claim 2 further comprising an electric discharge circuit for discharging the electric discharge circuit so as to trigger the electromagnetic driver, said electric discharge circuit being connected to said electromagnetic coil.
4. The apparatus as defined in claim 3 further comprising a control circuit for timing the electrical discharge circuit, said control circuit being connected to said electric discharge circuit.
5. The apparatus as defined in claim 2 wherein the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member to form the structural member.
6. A method of forming a metal blank into a structural member of a predetermined shape comprising the following steps:
placing the metal blank in a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank to form a hydroformed member; and applying electromagnetic energy for at least one of trimming and piercing the hydroformed member while the hydroformed member remains in the hydroforming mold.
placing the metal blank in a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank to form a hydroformed member; and applying electromagnetic energy for at least one of trimming and piercing the hydroformed member while the hydroformed member remains in the hydroforming mold.
7. The method as defined in claim 6 wherein the step of applying electromagnetic energy includes the steps of delivering an electric current to an electromagnetic coil and inducing a current in an electromagnetic driver, said electromagnetic driver including a trimming/piercing tool, and wherein said structural member is trimmed/pierced by the trimming/piercing tool as a result of the repulsive forces generated by the induced current in the driver.
8. The method as defined in claim 7 wherein the driver is formed by disposing an electromagnetic top plate on the driver opposite to the electromagnetic coil.
9. The method as defined in claim 7, wherein said hydroforming mold comprises more than one electromagnetic trimming/piercing assemblies, said method comprising the further step of controlling the more than one electromagnetic trimming/piercing assemblies by a control circuit for controlling the discharge circuit.
10. The method as defined in claim 9 wherein the control circuit times an electrical discharge such that all discharges are occurring in a predetermined sequence.
11. The method as defined in claim 9 wherein the control circuit times an electrical discharge such that all discharges are substantially simultaneous.
12. The method as defined in claim 7 wherein the trimming/piercing tool is a punch tool for providing an opening through an interior wall portion of the hydroformed member.
13. The method as defined in claim 7 wherein the trimming/piercing tool is a punch tool for providing notches or cut-out sections in the hydroformed member.
14. A method of forming a structural member of a predetermined shape comprising the following steps:
placing a metal blank into a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank into a hydroformed member;
energizing an electric discharge circuit for creating an electromagnetic force sufficient for driving an electromagnetic driver; and discharging the electric discharge circuit for driving the electromagnetic driver toward the hydroformed member, said electromagnetic driver comprising a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape.
placing a metal blank into a hydroforming mold, said hydroforming mold comprising an electromagnetic trimming/piercing assembly;
hydroforming the metal blank into a hydroformed member;
energizing an electric discharge circuit for creating an electromagnetic force sufficient for driving an electromagnetic driver; and discharging the electric discharge circuit for driving the electromagnetic driver toward the hydroformed member, said electromagnetic driver comprising a trimming/piercing tool for trimming/piercing the hydroformed member at a predetermined location to yield the predetermined shape.
15. The method as defined in claim 14 wherein the structural member is for use as a structural member in automotive applications.
16. A method of forming a tubular member comprising the steps of:
providing a tubular member having an inner circumferential surface and an outer circumferential surface;
mounting a tool mandrel within the tubular member, said tool mandrel having an outer forming surface;
providing electromagnetic energy to at least a portion along an axial extent of the tubular member for pushing the at least one portion of said tubular member against said tool mandrel, wherein said inner and outer circumferential surface of said tubular member assume a complementary shape to the outer forming surface of the tool mandrel.
providing a tubular member having an inner circumferential surface and an outer circumferential surface;
mounting a tool mandrel within the tubular member, said tool mandrel having an outer forming surface;
providing electromagnetic energy to at least a portion along an axial extent of the tubular member for pushing the at least one portion of said tubular member against said tool mandrel, wherein said inner and outer circumferential surface of said tubular member assume a complementary shape to the outer forming surface of the tool mandrel.
17. The method as defined in claim 16 wherein the electromagnetic energy is provided by means of an electromagnetic coil assembly to the at least one portion of the tubular member.
18. The method as defined in claim 17 wherein the electromagnetic coil assembly comprises an electromagnetic coil provided within a space of a supporting member.
19. The method as defined in claim 18 wherein the supporting member is made from a non-metallic material.
20. The method as defined in claim 18 wherein the electromagnetic coil is electrically insulated.
21. The method as defined in claim 20 wherein the electromagnetic coil is electrically insulated by covering the electromagnetic coil with an electrically insulating material.
22. The method as defined in claim 20 wherein the electromagnetic coil is electrically insulated by filling the space within the supporting member with an electrically insulating material.
23. The method as defined in claim 18 wherein the electromagnetic coil is in communication with a control circuit.
24. The method as defined in claim 23 wherein the control circuit is for one of charging and discharging the electromagnetic coil.
25. The method as defined in claim 16 further comprising the step of removing the tool mandrel from the tubular member.
26. The method as defined in claim 16 wherein the tool mandrel is a releasable two-part mandrel comprising a first mandrel member and a second mandrel member.
27. The method as defined in claim 26 further comprising the step of removing the tool mandrel from the tubular member.
28. The method as defined in claim 27 wherein the step of removing the tool mandrel from the tubular member comprises the prior step of releasing the two-part mandrel into the first mandrel member and the second mandrel member.
29. The method as defined in claim 16 wherein a cross-sectional configuration of the complementary shape corresponds to one of a circular, a rectangular, a cross-shaped, a flanged and dished head, a cylindrical shell, a stepped cover, a re-entrant flared shape, a venturi shape, a hemispherical shape, a flanged cover, a cone shape, and a parabolic nose shape cross-sectional configuration.
30. A method of forming a tubular member comprising the following steps:
providing a tubular member having a bore therethrough, said tubular member having an outer surface and an inner surface;
placing a mandrel inside said bore, said mandrel having an outer forming surface;
placing a first electromagnetic coil around at least a portion of the outer surface of the tubular member;
providing a first electric discharge circuit in communication with said first electromagnetic coil, said first electric discharge circuit including a first electric power source and a first discharge switch; and activating said first discharge switch for discharging the electric current through said first electromagnetic coil and thereby producing electromagnetic energy for moving said tubular member towards said mandrel, whereby said tubular member assumes a complementary shape to said outer forming surface of the mandrel.
providing a tubular member having a bore therethrough, said tubular member having an outer surface and an inner surface;
placing a mandrel inside said bore, said mandrel having an outer forming surface;
placing a first electromagnetic coil around at least a portion of the outer surface of the tubular member;
providing a first electric discharge circuit in communication with said first electromagnetic coil, said first electric discharge circuit including a first electric power source and a first discharge switch; and activating said first discharge switch for discharging the electric current through said first electromagnetic coil and thereby producing electromagnetic energy for moving said tubular member towards said mandrel, whereby said tubular member assumes a complementary shape to said outer forming surface of the mandrel.
31. The method as defined in claim 30 wherein the first electromagnetic coil is embedded within a space of a supporting member.
32. The method as defined in claim 31 wherein the supporting member is made from a non-metallic material.
33. The method as define in claim 30 wherein the first electromagnetic coil is electrically insulated.
34. The method as defined in claim 33 wherein the first electromagnetic coil is electrically insulated by covering said first electromagnetic coil with an electrically insulating material.
35. The method as defined in claim 33 wherein the first electromagnetic coil is electrically insulated by filling the space of the supporting member with an electrically insulating material.
36. The method as defined in claim 30 wherein said first electric discharge circuit is in communication with a first control circuit.
37. The method as defined in claim 36 wherein the first control circuit is for one of charging and discharging said first electric discharge circuit.
38. The method as defined in claim 37 wherein said first discharge switch is activated in response to a signal from the first control circuit.
39. The method as defined in claim 30 comprising the further step of placing at least a second electromagnetic coil around at least a second portion of the outer surface of the tubular member along an axial extent of said tubular member.
40. The method as defined in claim 39 comprising the further step of providing at least a second electric discharge circuit in communication with said second electromagnetic coil, said second electric discharge circuit including a second electric power source and a second discharge switch.
41. The method as defined in claim 40 wherein said second electric discharge circuit is in communication with the control circuit.
42. The method as defined in claim 41 wherein the first control circuit times an electrical discharge of the first and the second electric discharge circuit such that the discharge of the first and the second electric discharge circuit occur in a predetermined sequence.
43. The method as defined in claim 41 wherein the first control circuit times an electrical discharge of the first and the second electric discharge circuit such that the discharge of the first and the second electric discharge circuit occur substantially simultaneous.
44. The method as defined in claim 40 wherein said second electric discharge circuit is in communication with a second control circuit, and wherein the second control circuit is for timing an electrical discharge of the second electric discharge circuit.
45. The method as defined in claim 30 comprising the further step of removing the mandrel from the bore of the tubular member.
46. The method as defined in claim 30 wherein the mandrel is a releasable two-part mandrel comprising a first mandrel member and a second mandrel member
47. The method as defined in claim 46 further comprising the step of removing the mandrel from the bore of the tubular member
48. The method as defined in claim 47 wherein the step of removing the mandrel from the bore of the tubular member comprises the prior step of releasing the two-part mandrel into the first mandrel member and the second mandrel member.
49. A method of forming a hollow tubular member comprising the following steps:
providing a substantially hollow tubular member defining at least a central bore therethrough, said hollow tubular member having an outer surface and an inner surface;
placing a mandrel inside the bore, said mandrel having an outer forming surface; and applying electromagnetic energy for forming the hollow tubular member whereby said hollow tubular member moves toward the forming surface of the mandrel and whereby the inner surface of the hollow tubular member is complementary to the outer forming surface of the mandrel.
providing a substantially hollow tubular member defining at least a central bore therethrough, said hollow tubular member having an outer surface and an inner surface;
placing a mandrel inside the bore, said mandrel having an outer forming surface; and applying electromagnetic energy for forming the hollow tubular member whereby said hollow tubular member moves toward the forming surface of the mandrel and whereby the inner surface of the hollow tubular member is complementary to the outer forming surface of the mandrel.
50. A method of forming a tubular metal member comprising the following steps:
providing a tubular member having a passage therethrough;
providing a tool mandrel in said passage, said tool mandrel having a forming surface for forming the tubular member; and pushing at least a portion of the tubular member onto the tool mandrel for obtaining the formed tubular member, said formed tubular member attaining a predetermined shape in correspondence with the forming surface of the tool mandrel, and wherein said step of pushing is achieved by providing electromagnetic energy to the at least one portion of the tubular member.
providing a tubular member having a passage therethrough;
providing a tool mandrel in said passage, said tool mandrel having a forming surface for forming the tubular member; and pushing at least a portion of the tubular member onto the tool mandrel for obtaining the formed tubular member, said formed tubular member attaining a predetermined shape in correspondence with the forming surface of the tool mandrel, and wherein said step of pushing is achieved by providing electromagnetic energy to the at least one portion of the tubular member.
51. A method of making a camshafft assembly comprising the following steps:
providing a plurality of cam and journal elements, each element including an axial opening;
securing the plurality of cam and journal elements in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis;
inserting a hollow shaft through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements;
and providing electromagnetic energy to at least a portion of the hollow shaft along an axial extent of the hollow shaft for expanding the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam elements and journal and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined fixed orientation and spacing.
providing a plurality of cam and journal elements, each element including an axial opening;
securing the plurality of cam and journal elements in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis;
inserting a hollow shaft through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements;
and providing electromagnetic energy to at least a portion of the hollow shaft along an axial extent of the hollow shaft for expanding the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam elements and journal and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined fixed orientation and spacing.
52. The method as defined in claim 51 wherein the step of securing the plurality of cam and journal elements comprises the step of aligning the plurality of cam and journal elements in a tool.
53. The method as defined in claim 51 wherein the step of providing electromagnetic energy includes the step of delivering an electric current to an electromagnetic coil provided inside the hollow shaft and inducing a current in the hollow shaft, wherein said hollow shaft is expanded as a result of the repulsive force generated by the induced current in the hollow shaft.
54. The method as defined in claim 51 wherein the electromagnetic energy is provided by means of an electromagnetic coil.
55. The method as defined in claim 51 comprising the further steps of providing an electric discharge circuit in communication with the electromagnetic coil and activating said first discharge switch for discharging the electric current through the electromagnetic coil and thereby producing electromagnetic energy for expanding the hollow shaft.
56. The method as defined in claim 55 comprising the further step of controlling the electric discharge circuit by means of a control circuit.
57. The method as defined in claim 56 wherein the control circuit is for one of charging and discharging the electromagnetic coil.
58. The method as defined in claim 51 wherein the axial opening is one of a circular and a non-circular opening.
59. The method as defined in claim 58 wherein the non-circular axial opening is for providing a high torque capability of the mechanical locking relationship between the hollow shaft and the plurality of cam and journal elements.
60. The method as defined in claim 51 wherein the step of securing the plurality of cam and journal elements is performed by a plurality of supporting and positioning elements.
61. The method as defined in claim 60 wherein the plurality of cam and journal elements are separated by a plurality of spacer elements.
62. The method as defined in claim 51 comprising the further step of grinding wearing surfaces of the plurality of cam and journal elements to a desired surface finish and dimensions.
63. A method of making a camshaft assembly comprising the following steps:
providing a plurality of cam and journal elements, each element including an axial opening;
securing the plurality of cam and journal elements in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis;
inserting a hollow shaft through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements;
providing diametral clearance around portions adjacent the plurality of cam and journal elements;
energizing an electric discharge circuit for creating an electromagnetic force sufficient for expanding the hollow shaft; and discharging the electric discharge circuit for expanding the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam and journal elements and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined fixed orientation and spacing.
providing a plurality of cam and journal elements, each element including an axial opening;
securing the plurality of cam and journal elements in a predetermined fixed orientation and spacing with their axial openings aligned on a common axis;
inserting a hollow shaft through the axial openings along the common axis in close-fitting relation with the openings of the plurality of cam and journal elements;
providing diametral clearance around portions adjacent the plurality of cam and journal elements;
energizing an electric discharge circuit for creating an electromagnetic force sufficient for expanding the hollow shaft; and discharging the electric discharge circuit for expanding the hollow shaft into a mechanical locking relationship with the openings of the plurality of cam and journal elements and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined fixed orientation and spacing.
64. The method as defined in claim 60 comprising the further step of controlling the electric discharge circuit by means of a control circuit.
65. The method as defined in claim 61 wherein the control circuit is for one of charging and discharging the electromagnetic coil.
66. The method as defined in claim 60 wherein the step of securing the plurality of cam and journal elements comprises the step of aligning the plurality of cam and journal elements in a tool.
67. The method as defined in claim 60 wherein the axial opening is one of a circular and a non-circular opening.
68. The method as defined in claim 64 wherein the non-circular axial opening is for providing a high torque capability of the mechanical locking relationship between the hollow shaft and the plurality of cam and journal elements.
69. A method of manufacturing a camshaft assembly comprising the following steps:
providing a plurality of cam lobe and journal elements, said elements each including an axial opening;
securing said plurality of cam lobe and journal elements in a tool with their axial openings in alignment, said plurality of cam lobe and journal elements being arranged in said tool in a predetermined longitudinally spaced apart relationship, and said cam lobe elements being arranged in a predetermined angularly oriented relationship to one another inserting a hollow shaft through the axial openings in close-fitting relationship with said openings providing diametral clearance around portions adjacent the plurality of cam lobe and journal elements providing electromagnetic energy to at least a portion along an axial extent of the hollow shaft for expanding the hollow shaft into mechanical interference engagement with the openings of the plurality of cam lobe and journal elements and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined longitudinally spaced apart relationship and predetermined angularly oriented relationship.
providing a plurality of cam lobe and journal elements, said elements each including an axial opening;
securing said plurality of cam lobe and journal elements in a tool with their axial openings in alignment, said plurality of cam lobe and journal elements being arranged in said tool in a predetermined longitudinally spaced apart relationship, and said cam lobe elements being arranged in a predetermined angularly oriented relationship to one another inserting a hollow shaft through the axial openings in close-fitting relationship with said openings providing diametral clearance around portions adjacent the plurality of cam lobe and journal elements providing electromagnetic energy to at least a portion along an axial extent of the hollow shaft for expanding the hollow shaft into mechanical interference engagement with the openings of the plurality of cam lobe and journal elements and diametrically outwards adjacent the elements to secure the elements permanently on the hollow shaft in said predetermined longitudinally spaced apart relationship and predetermined angularly oriented relationship.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87207006P | 2006-11-30 | 2006-11-30 | |
| US60/872,070 | 2006-11-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2612998A1 true CA2612998A1 (en) | 2008-05-30 |
| CA2612998C CA2612998C (en) | 2017-02-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2612998A Expired - Fee Related CA2612998C (en) | 2006-11-30 | 2007-11-30 | Electromagnetic (em) metal forming techniques for hydroforming pierce punches drive via em energy, for forming tubular metal workpieces over a mandrel, and for making camshaft assemblies |
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| Country | Link |
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| CA (1) | CA2612998C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101538991B (en) * | 2009-04-04 | 2013-04-03 | 西北大学 | Electromagnetic method pipe fitting shaping technique |
| CN112846665A (en) * | 2021-01-06 | 2021-05-28 | 王志刚 | Production method of axial metal sealing ring |
-
2007
- 2007-11-30 CA CA2612998A patent/CA2612998C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101538991B (en) * | 2009-04-04 | 2013-04-03 | 西北大学 | Electromagnetic method pipe fitting shaping technique |
| CN112846665A (en) * | 2021-01-06 | 2021-05-28 | 王志刚 | Production method of axial metal sealing ring |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2612998C (en) | 2017-02-07 |
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