Deep-cup-shaped thin-wall part current auxiliary composite spinning forming device and method

Abstract

The present invention discloses a current-assisted composite spinning forming device and method for deep cup-shaped thin-walled parts is provided, comprising a spinning mandrel, a tailstock, and a plurality of rollers evenly distributed on the circumference of the spinning mandrel; the rollers are arranged in a staggered manner in the axial and radial directions of the spinning mandrel, and the roller surface of each roller comprises a deep drawing roller surface, a flow spinning section, and a shaping roller surface, wherein the staggered arrangement means that the deep drawing roller surfaces, the flow spinning sections and the shaping roller surfaces of the rollers are distributed in a staggered manner in the axial and radial directions of the spinning mandrel. In the spinning process, with different arc-shaped surface shapes and structures of the rollers for deep drawing spinning, the rollers focus on applying pressure to different portions of a blank in the period of each revolution of the spinning mandrel, which is beneficial to increase the pass reduction and reduce the spinning pass. This can not only improve the production efficiency, but also contribute to reducing defects such as material rupture and unusability due to hardening of the workpiece that is caused by the discontinuous material forming process.

1 . A current-assisted composite spinning forming device for deep cup-shaped thin-walled parts, comprising a spinning mandrel ( 4 ), a tailstock ( 6 ), and a plurality of rollers ( 3 ) evenly distributed on the circumference of the spinning mandrel ( 4 ), characterized in that: the rollers ( 3 ) are arranged in a staggered manner in the axial and radial directions of the spinning mandrel ( 4 ), and the roller surface of each roller ( 3 ) comprises a deep drawing roller surface ( 1 ), a flow spinning section, and a shaping roller surface ( 2 ), wherein the staggered arrangement means that the deep drawing roller surfaces ( 1 ), the flow spinning sections and the shaping roller surfaces ( 2 ) of the rollers ( 3 ) are distributed in a staggered manner in the axial and radial directions of the spinning mandrel ( 4 ). 
     
     
         2 . The current-assisted composite spinning forming device for deep cup-shaped thin-walled parts according to  claim 1 , characterized in that: the number of the rollers ( 3 ) is at least three, with the staggered distribution specifically as follows:
 the section line of the deep drawing roller surface ( 1 ) of each roller ( 3 ) is an arc line, with the arc radii of the deep drawing roller surfaces ( 1 ) gradually decreasing in turn;   the section shape of the shaping roller surface ( 2 ) of each roller ( 3 ) is a straight line; according to the spinning sequence, the inclination angles of the shaping roller surfaces ( 2 ) of the first two adjacent rollers ( 3 ) relative to the axis of the spinning mandrel ( 4 ) are the same or decrease in turn, and the inclination angle of the shaping roller surface ( 2 ) of the third roller ( 3 ) relative to the axis of the spinning mandrel ( 4 ) is smaller than that of the first two rollers ( 3 ); and   each flow spinning section is of a conical structure, which refers to a tip fillet at the connection between the arc line of the deep drawing roller surface ( 1 ) and the straight line of the shaping roller surface ( 2 ), with the tip fillets of the flow spinning sections gradually staggered in turn.   
     
     
         3 . The current-assisted composite spinning forming device for deep cup-shaped thin-walled parts according to  claim 2 , characterized in that: the inclination angles of the first two adjacent rollers ( 3 ) are the same in the range of 2° to 3°, or decrease in turn in the range of 2° to 3°, while the inclination angle of the third roller ( 3 ) is in the range of 0.50 to 1°. 
     
     
         4 . The current-assisted composite spinning forming device for deep cup-shaped thin-walled parts according to  claim 3 , characterized in that: the device also includes a reverse thrust plate ( 5 ) against the edge of a blank ( 7 ); two electrodes are provided respectively at the reverse thrust plate ( 5 ) and the tailstock ( 6 ), the one on the reverse thrust plate ( 5 ) being the negative electrode and the other one on the tailstock ( 6 ) the positive electrode; and in a spinning process, a pulse current is applied to the tailstock ( 6 ) and the reverse thrust plate ( 5 ), and flows from the central area of the blank ( 7 ) to the edge to act as current-assisted spinning. 
     
     
         5 . The current-assisted composite spinning forming device for deep cup-shaped thin-walled parts according to  claim 4 , characterized in that: the blank ( 7 ) is made of alloy structural steel, and the pulse current is 1100-1400 A during the current-assisted spinning. 
     
     
         6 . The current-assisted composite spinning forming device for deep cup-shaped thin-walled parts according to  claim 5 , characterized in that: when there are three rollers ( 3 ), they are evenly distributed on the circumference of the spinning mandrel ( 4 ) at an interval of 120°. 
     
     
         7 . A current-assisted composite spinning forming method for deep cup-shaped thin-walled parts, characterized in that: the method is implemented by using the device according to  claim 1 , and comprises the following steps:
 the tailstock ( 6 ) is used to center the round plate-shaped blank ( 7 ) against the spinning mandrel ( 4 );   a thrust is applied to the reverse thrust plate ( 5 ) in the axial direction of the spinning mandrel ( 4 ), i.e., toward the blank ( 7 ), so as to press the reverse thrust plate ( 5 ) against the edge of the blank ( 7 ); and a pulse current is applied to the tailstock ( 6 ) and the reverse thrust plate ( 5 ), and flows from the central area of the blank ( 7 ) to the edge to act as the current-assisted spinning;   the deep drawing roller surface ( 1 ) of the roller ( 3 ) is put in a working station; when there are three rollers ( 3 ), the arc radii of their deep drawing roller surfaces ( 1 ) and the inclination angles of their shaping roller surfaces ( 2 ) gradually decrease in turn; correspondingly, the gaps between the tip fillets of the conical structures of the flow spinning sections and the spinning mandrel ( 4 ) gradually decrease; and   the spinning mandrel ( 4 ) spins; according to the order in which the arc radii of the rollers are arranged from large to small, the deep drawing roller surfaces ( 1 ) gradually perform deep drawing spinning on the blank ( 7 ) in turn; the deep drawing spinning is carried out until the tip fillet of the flow spinning section is reached, and then flow spinning is performed on the blank ( 7 ) to complete deep drawing and thinning of the blank ( 7 ); then the shaping roller surface ( 2 ) is reached, and smoothing and shaping is gradually performed on the surface of the thinned blank ( 7 ); when the deep drawing spinning, flow spinning and shaping spinning processes on the blank ( 7 ) are completed, the three processes of deep drawing spinning, flow spinning and shaping spinning can then be completed through one feeding of the roller, until an entire deep cup-shaped part with a required wall thickness is obtained.   
     
     
         8 . The current-assisted composite spinning forming method for deep cup-shaped thin-walled parts according to  claim 7 , characterized in that: the final wall thickness of the formed deep cup-shaped part is determined by the roller ( 3 ) with the smallest gap between the tip fillet of the flow spinning section and the axial surface of the spinning mandrel ( 4 ). 
     
     
         9 . The current-assisted composite spinning forming method for deep cup-shaped thin-walled parts according to  claim 8 , characterized in that: the excess edge of the mouth of the deep cup-shaped part is cut off after the deep cup-shaped part reaches the desired wall thickness.