Metal Spinning Method and Apparatus

Abstract

A method and an apparatus for a metal spinning operation capable of spinning a product having a non-circular cross section normal to an axis of rotation such as a polygonal/elliptic one. The actuators of a forming roller (5) are driven with feedback signals from a force sensor (8) fitted to the forming roller (5) to control the pushing force of the forming roller (5) so as to form a work (1) following the cross section shape of a mandrel (3), so that the product having the non-circular cross section normal to the axis of rotation can also be formed. The motion of the forming roller (5) in the forming operation is stored, the shape of the mandrel (3) near the point of the forming roller (5) contacting with the work (1) is estimated based on the motion of the forming roller (5) from a time point before one rotation of the mandrel (3), and according to the estimation, the rotational speed of a motor for rotating the mandrel (3) is controlled for the forming operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] A schematic diagram of an embodiment of an apparatus for performing a spinning method of the invention

[FIG. 2] A diagram showing forces to act on a forming roller

[FIG. 3] A diagram showing a summary of controls in forming

[FIG. 4] A diagram showing the sectional shape of a product and a feed in the radial direction

[FIG. 5] A diagram for explaining the functions of a jig at a forming starting time

[FIG. 6] A diagram showing an experimental apparatus for verifying the spinning method and apparatus according to the invention

[FIG. 7] A diagram showing one mandrel used in the experiments

[FIG. 8] A diagram showing an experimentally obtained graph (plotting the forming roller displacements in the X direction parallel to and in the Y direction normal to the axis of rotation)

[FIG. 9] A diagram showing an experimentally obtained graph (in which the distance to the center position of the forming roller with respect to the mandrel axis is plotted)

[FIG. 10] A diagram showing a forming force to be applied to the material by the forming roller

[FIG. 11] A diagram presenting the photographs of the mandrel 26 and the formed product

[FIG. 12] A diagram presenting the result of comparing the side surface shape of the mandrel of the planar parts and the outer shape of the product, by using a laser displacement sensor

[FIG. 13] A diagram showing the shape of another mandrel used in the experiments

[FIG. 14] A diagram presenting the results, in which the forming operations are performed by changing the pushing force Fn and the roller feed and in which the forming propriety is examined

[FIG. 15] A diagram presenting a photograph of a product

[FIG. 16] A diagram showing the photographs of the well-shaped product and the mandrel 28

[FIG. 17] A diagram presenting the results, in which the laser displacement sensor is used to compare the side surface shapes of 20 degrees and 40 degrees of the mandrel of the planar part and the outer shape of the product

[FIG. 18] A diagram showing a two-pass forming operation

[FIG. 19] A diagram showing the speeds of the forming roller at the time when the positions of (a) 5 mm and (b) 20 mm from the top are processed

[FIG. 20] A diagram showing the change in the mandrel speed from the start to the end of the forming operation

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

• 1, 9 WORK
• 1 a INITIAL SHAPE OF WORK
• 1 b FINAL SHAPE OF WORK
• 2 JIG
• 3, 23, 26, 28 MANDREL
• 4, 21, 22, 24 MOTOR
• 5, 20 FORMING ROLLER
• 6, 7 LINEAR MOTION TABLE
• 8 FORCE SENSOR
• 9, 9′ CROSS SECTION OF MANDREL
• 10 SECTION OF NO CHANGE IN RADIAL FEED
• 11 SECTION OF LARGE CHANGE IN RADIAL FEED
• 25 6-AXIS FORCE SENSOR
• 27 REDUCTION GEAR

Claims

1. A metal spinning method for forming a work of a metal sheet by pushing the work onto a rotating mandrel using a forming roller, the metal spinning method comprising the steps of:driving actuators of the forming roller with feedback signals from a force sensor fitted to the forming roller, to control the pushing force of the forming roller; andforming the work following the cross section shape of the mandrel, so that the product having the non-circular cross section normal to the axis of rotation can be formed.

2. The metal spinning method as set forth in claim 1, wherein the motion of the forming roller in the forming operation is stored;the shape of the mandrel near the point of the forming roller contacting with the work is estimated based on the motion of the forming roller from a time point before one rotation of the mandrel; andaccording to the estimation, the rotational speed of a motor for rotating the mandrel is controlled for the forming operation.

3. The metal spinning method as set forth in claim 1, wherein a jig shaped to merge into the front surface of the mandrel is used to clamp the work fixedly between the mandrel and the jig; andthe forming roller is fed at first in the direction of the axis of rotation of the mandrel while being pushed onto the jig, so that the forming operation of the work is smoothly started.

4. A metal spinning apparatus comprising: a forming roller having a force sensor fixed thereto, andactuators for driving the forming roller, whereinthe actuators drive the forming roller to spin a work of a metal sheet by pushing the work onto a rotating mandrel;the actuators control the pushing force of the forming roller with feedback signals from the force sensor; andthe forming roller forms the work following the cross section shape of the mandrel, so that the product having the non-circular cross section normal to the axis of rotation of the mandrel can also be formed.

5. The metal spinning apparatus as set forth in claim 4, wherein the motion of the forming roller in the forming operation is stored;the shape of the mandrel near the point of the forming roller contacting with the work is estimated based on the motion of the forming roller from a time point before one rotation of the mandrel; andaccording to the estimation, the rotational speed of a motor for rotating the mandrel is controlled.

6. The metal spinning apparatus as set forth in claim 4, further comprising: a jig shaped to merge into the front surface of the mandrel and capable of clamping the work fixedly between the mandrel and the jig; andthe forming roller is fed at first in the direction of the axis of rotation of the mandrel while being forced onto the jig, so that the forming operation of the work is smoothly started.