Abstract: A cutting device for a thin metallic plate is provided which shortens time for shaping or the like on a cut edge to improve manufacturing efficiency, and increases the life of a cutter. The cutting device for cutting a thin metallic plate W with a predetermined width includes a shearing cutter 7 which is made of a metal having a higher hardness than the thin plate W and has a blade angle of 50 to 90°. A contacting member 5 is provided which includes a groove 8 facing the shearing cutter 7 and makes contact with the back side of the thin plate W. In the groove 8, an interval a between upper edges 9a and 9b of inner walls 9 is set at 15 to 30 times a thickness b of the thin plate W. A depth c of a deepest portion 11 in the groove 8 is set at one to three times the thickness b of the thin plate W. The inner walls 9 of the groove 8 include curved surfaces 10, each of which has a curvature radius of 15 to 50 times the thickness b of the thin plate.

Abstract: There are disclosed a method and device for polishing a metal ring, which is capable of polishing a side edge of the metal ring without performing barrel polishing or polishing by grinding stones. Subsequently to a projecting step of projecting a metal ring W by clearing means 6, a first brush polishing step of polishing one edge of the metal ring W by a polishing brush 60 is performed. Subsequently, an inverting step of inverting the metal ring W whose one edge is polished by the first brush polishing step is inverted by the inverting means 10 is performed. Subsequently, a second brush polishing step of polishing the other edge of the metal ring W which is inverted by the inverting step by the polishing brush 60 is performed. Moreover, a clearing step of clearing the metal ring whose other edge is polished by the second brush polishing step by clearing means 7 is performed.

Abstract: There are disclosed a method and device for polishing a metal ring, which is capable of polishing a side edge of the metal ring without performing barrel polishing or polishing by grinding stones. Subsequently to a projecting step of projecting a metal ring W by clearing means 6, a first brush polishing step of polishing one edge of the metal ring W by a polishing brush 60 is performed. Subsequently, an inverting step of inverting the metal ring W whose one edge is polished by the first brush polishing step is inverted by the inverting means 10 is performed. Subsequently, a second brush polishing step of polishing the other edge of the metal ring W which is inverted by the inverting step by the polishing brush 60 is performed. Moreover, a clearing step of clearing the metal ring whose other edge is polished by the second brush polishing step by clearing means 7 is performed.

Abstract: A cutting device for a thin metallic plate is provided which shortens time for shaping or the like on a cut edge to improve manufacturing efficiency, and increases the life of a cutter. The cutting device for cutting a thin metallic plate W with a predetermined width includes a shearing cutter 7 which is made of a metal having a higher hardness than the thin plate W and has a blade angle of 50 to 90°. A contacting member 5 is provided which includes a groove 8 facing the shearing cutter 7 and makes contact with the back side of the thin plate W. In the groove 8, an interval a between upper edges 9a and 9b of inner walls 9 is set at 15 to 30 times a thickness b of the thin plate W. A depth c of a deepest portion 11 in the groove 8 is set at one to three times the thickness b of the thin plate W. The inner walls 9 of the groove 8 include curved surfaces 10, each of which has a curvature radius of 15 to 50 times the thickness b of the thin plate.

Abstract: A forging die apparatus comprises a punch for applying a pressurizing force to a forging material arranged in a cavity, a cylindrical member installed to surround a part of outer circumference of the punch, for making displacement integrally with the punch, and a first ring member formed with a hole for forcibly inserting the cylindrical member therein when the punch applied the pressurizing force to the forging material.

Abstract: A forging die apparatus comprises a punch for applying a pressurizing force to a forging material arranged in a cavity, a cylindrical member installed to surround a part of outer circumference of the punch, for making displacement integrally with the punch, and a first ring member formed with a hole for forcibly inserting the cylindrical member therein when the punch applied the pressurizing force to the forging material.

Abstract: In order to obtain uniform pressing force applied to a workpiece by an ironing die and easily disengage the workpiece after completing plastic working for the workpiece, a forming machine for performing the plastic working for the workpiece has a base pedestal, a forming punch provided on the base pedestal, and an annular ironing die arranged over the forming punch. The forming punch comprises a main punch body, six punch collets to be engaged with the main punch body and separated from each other at equal angles, a metal sleeve externally fitted to the main punch body and the punch collets, and a holder for holding the metal sleeve.

Abstract: A hydraulic pressure control apparatus comprises a high pressure accumulator for sucking pressure oil supplied to a relief chamber of a relief valve to make changeover for the relief valve from a valve-closed state to a valve-open state when a forming load is applied to the pressure oil charged in a pressure chamber and the hydraulic pressure of the pressure oil arrives at a relief preset pressure, and a low pressure accumulator for sucking the pressure oil charged in the pressure chamber via the relief valve which is in the valve-open state.

Abstract: In order to obtain uniform pressing force applied to a workpiece by an ironing die and easily disengage the workpiece after completing plastic working for the workpiece, a forming machine for performing the plastic working for the workpiece has a base pedestal, a forming punch provided on the base pedestal, and an annular ironing die arranged over the forming punch. The forming punch comprises a main punch body, six punch collets to be engaged with the main punch body and separated from each other at equal angles, a metal sleeve externally fitted to the main punch body and the punch collets, and a holder for holding the metal sleeve.

Abstract: A hydraulic pressure control apparatus comprises a high pressure accumulator for sucking pressure oil supplied to a relief chamber of a relief valve to make changeover for the relief valve from a valve-closed state to a valve-open state when a forming load is applied to the pressure oil charged in a pressure chamber and the hydraulic pressure of the pressure oil arrives at a relief preset pressure, and a low pressure accumulator for sucking the pressure oil charged in the pressure chamber via the relief valve which is in the valve-open state.

Abstract: A hydraulic pressure control apparatus comprises a high pressure accumulator for sucking pressure oil supplied to a relief chamber of a relief valve to make changeover for the relief valve from a valve-closed state to a valve-open state when a forming load is applied to the pressure oil charged in a pressure chamber and the hydraulic pressure of the pressure oil arrives at a relief preset pressure, and a low pressure accumulator for sucking the pressure oil charged in the pressure chamber via the relief valve which is in the valve-open state.

Abstract: A forging die apparatus comprises a punch for applying a pressurizing force to a forging material arranged in a cavity, a cylindrical member installed to surround a part of outer circumference of the punch, for making displacement integrally with the punch, and a first ring member formed with a hole for forcibly inserting the cylindrical member therein when the punch applies the pressurizing force to the forging material.

Abstract: A forge-molding method for forming a constant velocity joint outer ring comprising a shaft and a cup formed integral with and expanding radially and outwardly from one end of the shaft is provided. The method uses an ironing die apparatus which is provided with a lower molding die, an upper molding die and an ironing punch. The lower molding die is provided with a first cavity formed to have a final degree of product accuracy with respect to the shaft and adapted to apply a final ironing process to the shaft, while the upper molding die is provided with a second cavity for restraining the outer peripheral surface of the cup. Consequently, the accuracy of concentricity between the shaft and the cup can be securely maintained in a simple manner and a sufficient degree of accuracy of the inner peripheral surface and/or the inner diameter of the cup can be effectively secured.

Abstract: A forging die apparatus comprises a punch for applying a pressurizing force to a forging material arranged in a cavity, a cylindrical member installed to surround a part of outer circumference of the punch, for making displacement integrally with the punch, and a first ring member formed with a hole for forcibly inserting the cylindrical member therein when the punch applies the pressurizing force to the forging material.

Abstract: A forming die is composed of a die member and a reinforcing member for applying compressive forces radially inwardly to the die member. To manufacture the forming die, tensile stresses applied to elements divided from the die member are simulated, and a fracture region of the die member is specified based on the simulated tensile stresses. An inner circumferential configuration of the reinforcing ring, or an outer circumferential configuration of the die member is determined for cooperation with the die member or the reinforcing ring in producing compressive stresses in the die member to counteract tensile stresses in the fracture region. The reinforcing ring with the inner circumferential configuration or the die member with the outer circumferential configuration is formed, and either the reinforcing ring with the inner circumferential configuration is over the die member, or the reinforcing ring is fitted over the die member with the outer circumferential configuration.