JP4763018B2 - Metal cylinder tube expansion apparatus and method - Google Patents

Description

  The present invention relates to a metal cylinder tube expansion device and a tube expansion method for expanding a metal cylinder into a conical shape.

  As for a metal can, for example, a pail can, a side plate is formed by winding a metal plate in a cylindrical shape and welding a seam, and a can is formed by joining the side plate and the bottom. There are two types of metal cans: a taper type in which the side surface portion tapers toward the bottom in the axial direction, and a straight type in which the side surface portion remains cylindrical.

  As for the taper type, first, a metal plate is rolled into a cylindrical shape, and a seam portion is welded to form a metal cylinder, and then the metal cylinder is expanded to have a tapered shape.

  As a method for expanding the metal cylinder, an expanding method or a Pascal method is used.

  In the Pascal system, a tube expansion member formed of an elastic body such as a rubber body is inserted into a metal cylinder, and the tube expansion member is inflated by pressurizing with a gas or liquid filled in the elastic body to expand the tube of the metal cylinder. I do. In this case, in order to determine the shape after the tube expansion, it is essential to dispose the mold on the outside of the metal cylinder, and it is adopted in the tube expansion pattern in which one of the end portions in the axial direction of the metal cylinder expands. Have difficulty. Therefore, the Pascal method cannot be adopted for the pipe expansion used in the tapered pail can.

  For the expand system, the expandable mold is placed inside the metal cylinder before tube expansion, and the metal cylinder is expanded from the inside to the outside by the expandable mold, so that the metal cylinder is expanded and formed into the final shape. . About the taper type, it can be expanded and formed by an expanding method.

  The expand type used for the taper type has a truncated cone shape as a whole, and has a plurality of segments having arcuate surfaces divided along the circumferential direction. Each segment can be moved in the radial direction of the expanding mold to widen the arc surface outward. This movement increases the diameter of the expanding mold, and the metal cylinder can be expanded from the inside to expand the tube.

  Usually, the radius of curvature of the arc surface of each expanded mold segment is formed to be equal to the radius of curvature of the expanded cylinder. Therefore, before the pipe expansion, as shown in FIG. 10A, the arc surface 41 of the segment 40 is in contact with the metal cylinder at the segment corner. On the other hand, Patent Document 1 describes a shape in which the radius of curvature of the arc surface of each segment is formed to be equal to the radius of curvature of the cylinder before tube expansion. This is to reduce the phenomenon of scratches on the inner surface of the metal cylinder due to friction between both edges of the arc surface of each segment and the inner surface of the metal cylinder.

JP 2007-203357 A

  In the expanding method, when using a conventional expanding type in which the radius of curvature of the arc surface 41 of the segment 40 is equal to the radius of curvature of the expanded cylinder, as shown in FIG. 10A, the metal cylinder 10 and the segment 40 are expanded during the expansion. The portion in contact with is a segment corner contact portion 42 in the vicinity of both edge portions of the segment arc surface. And when each segment moves so as to expand radially and pipe expansion is performed, the interval between both edges of one segment is kept constant, and the interval between the edges of adjacent segments increases. For this reason, when the metal cylinder is expanded, the portion 44 between the edges of one segment of the metal cylinder is not restricted in the direction of expanding in the circumferential direction, and between the edges of adjacent segments. The portion 45 is restrained in the direction of spreading in the circumferential direction. As a result, in the metal cylinder after the tube expansion, the portion 44 between both edges of one segment of the metal cylinder 10 has little circumferential extension, and conversely, the portion 45 between the edges of adjacent segments is There is much elongation in the circumferential direction.

  As a result of the pipe expansion as described above, the elongation of the portion 45 between the edges of the adjacent segments becomes a value larger than the average elongation in the circumferential direction of the metal cylinder due to the pipe expansion. The expansion limit is determined by the maximum elongation limit during expansion, so that the elongation of the portion 45 between the edges of adjacent segments reaches the critical elongation before the average circumferential elongation of the metal cylinder reaches the critical elongation. However, further tube expansion has been difficult.

  When expanding the tube, the metal cylinder 10 extends at a portion 44 between both edges of one segment, although it is smaller than the average elongation. When the metal cylinder extends, the segment corner contact portion 42 rubs the inner surface of the metal cylinder, so that the inner surface of the metal cylinder 10 is scratched.

  On the other hand, the thing of patent document 1 shape | molds the curvature radius of the circular arc surface of each segment equal to the curvature radius of the cylinder before pipe expansion. As shown in FIG. 10B, since the radius of curvature of the arc surface 41 is smaller than the target radius of curvature of the metal cylinder after the pipe expansion, the cross-sectional shape of the metal cylinder does not become circular after the pipe expansion, and the segment of the metal cylinder The polygonal shape is equal to the number of segments with the central contact portion 43 as a vertex.

  The present invention expands the expansion limit by obtaining uniform elongation at each part in the circumferential direction of the metal cylinder for expanding the metal cylinder into a conical shape, and the cross section of the metal cylinder after the expansion It is an object of the present invention to provide a metal cylinder tube expansion device and a tube expansion method which are formed into a circular shape having a target shape and do not cause scratches on the inner surface of the metal cylinder.

That is, the gist of the present invention is as follows.
(1) The tube expansion device for expanding the metal cylinder 10 includes a tube expansion jig 1, the tube expansion jig 1 includes a center cone 2 and a planetary roll group 5 disposed on the outer periphery thereof. The center cone 2 has a conical shape whose outer diameter changes in the axial direction of the center cone. The center cone 2 is integrally or divided in the axial direction, and the end of the center cone 2 on the side having the smaller outer diameter is referred to as a tip 20. The group 5 has a plurality of planetary rolls 4 arranged so as to surround the outer periphery of the center cone 8. When each planetary roll 4 rotates around the center cone 2, the group 5 rotates in conjunction with the outer periphery of each planetary roll 4. Is arranged so as to be in contact with the inner periphery of the metal cylinder 10 and the outer periphery of the center cone 2, and the surface of the planetary roll group 5 in contact with the metal cylinder 10 has a conical shape whose outer diameter changes in the axial direction. 10 and center The center cone 2 is moved in the axial direction with respect to the metal cylinder 10 while providing a difference in rotational speed around the center cone central axis between the cone 2 and the moving direction is a direction in which the tip 20 of the center cone is advanced. A tube expansion device characterized by being.
(2) When the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the center cone 2 and the planetary roll group 5 do not change their positions in the axial direction. apparatus.
(3) When the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the position of the center cone 2 and the planetary roll group 5 is changed mutually in the axial direction, and each planetary roll 4 is in the radial direction from the center cone central axis. The tube expansion device according to (1), wherein the tube expansion device is movable.
(4) The tube expansion device according to any one of (1) to (3), further including a holder 7 for holding a metal cylinder.
(5) After the metal cylinder 10 contacts the planetary roll 4, the holding of the metal cylinder 10 by the holder 7 can be released, and the tube expansion device according to (4) above.
(6) A tube expansion method for expanding the metal cylinder 10 using the tube expansion jig 1, wherein the tube expansion jig 1 has a center cone 2 and a planetary roll group 5 disposed on the outer periphery thereof, and the center cone 2 Is a conical shape whose outer diameter changes in the axial direction, the center cone 2 is integrally or divided in the axial direction, and the end of the center cone 2 on the side having the smaller outer diameter is referred to as a tip 10, 5 has a plurality of planetary rolls 4 arranged so as to surround the outer periphery of the center cone 2. When each planetary roll 4 rotates concentrically with the center cone 2, the planetary roll 4 rotates in conjunction with each other. The outer surface is arranged so as to be in contact with the outer periphery of the center cone 2, and the surface where the planetary roll group 5 is in contact with the metal cylinder 10 has a conical shape whose outer diameter changes in the axial direction. Contact the outer circumference of the roll 4 The center cone 2 is moved in the axial direction with respect to the metal cylinder 10 while providing a difference in rotational speed between the metal cylinder 10 and the center cone 2, and the moving direction is a direction in which the tip 10 of the center cone 2 moves forward. A tube expansion method characterized by being.
(7) When the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the center cone 2 and the planetary roll group 5 do not change their positions in the axial direction. Method.
(8) When the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the center cone 2 and the planetary roll group 5 change their positions relative to each other in the axial direction, and each planetary roll 4 is in the radial direction from the center cone central axis. The tube expansion method as described in (6) above, wherein

  In the present invention, when expanding the metal cylinder into a conical shape, the planetary roll group expands the tube while rotating relative to the inner periphery of the metal cylinder, so that uniform elongation is obtained at each part in the circumferential direction of the metal cylinder. As a result, the expansion limit is widened, the cross-sectional shape of the expanded metal cylinder can be formed into a target circular shape, and the expansion without causing scratches on the inner surface of the metal cylinder can be performed.

  The tube expansion apparatus and the tube expansion method of the metal cylinder of the present invention can perform taper type tube expansion in which the metal shape after the tube expansion is conical.

  First, the present invention will be described based on the embodiment shown in FIGS. The general requirements of the present invention described below are applicable not only to the embodiments shown in FIGS. 1 to 3 but also to any embodiment of FIGS.

  The tube expansion device of the present invention includes a tube expansion jig 1 and a holder 7 that holds a metal cylinder as necessary. The tube expansion jig 1 includes a center cone 2 and a planetary roll group 5 disposed on the outer periphery thereof. Have The metal cylinder 10 is arranged so as to rotate or not rotate around the center cone central axis. The center cone 2 has a conical shape whose outer diameter changes in the direction of the center cone axis. The center cone 2 is arranged so as to rotate or not rotate around its central axis. In some embodiments, the holder 7 is not required.

  The planetary roll group 5 has a plurality of planetary rolls 4 arranged so as to surround the outer periphery of the center cone 2. The outer periphery of each planetary roll 4 is disposed so as to contact the inner periphery of the metal cylinder 10 and the outer periphery of the center cone 2. The planetary roll group 5 is arranged so as to rotate (revolve) around the center cone or not to rotate. When the planetary roll group 5 is arranged so as to rotate around the center cone, the planetary rolls 4 are arranged so as to rotate in conjunction with each other when the planetary roll 4 rotates around the center cone central axis. Each planetary roll 4 is disposed so as to freely rotate (rotate) around the central axis of the planetary roll 4 itself. A planetary roll support plate 6 is provided at one end or both ends of the planetary roll group 5 in the planetary roll axial direction, and each planetary roll 4 is supported by the two planetary roll support plates 6. The two planetary roll support plates 6 can be connected to each other. In order to connect the two planetary roll support plates 6 to each other, support pillars 8 can be arranged between the planetary rolls.

  The number of planetary rolls 4 is preferably 8-15. As the number of planetary rolls 4 increases, the deformation of the metal cylinder 10 during tube expansion becomes uniform. However, as the number of planetary rolls 4 increases, the diameter of the planetary roll 4 needs to be reduced. Further, as the number of planetary rolls 4 increases and becomes thinner, it becomes necessary to dispose a large number of thin support pillars 8 of the planetary roll support plate 6. If the number of planetary rolls 4 is within the above preferred range, these problems will not occur. The number of planetary rolls 4 is more preferably 12-15.

  Of the three members of the metal cylinder 10, the center cone 2, and the planetary roll group 5, one is provided so as to freely rotate around the center cone central axis. For the remaining two, when expanding the tube, one is rotated and the other is not rotated (fixed), or both are rotated. When both of the remaining two are rotationally driven, the rotational speeds of the two are made different.

  For example, the metal cylinder 10 can be non-rotated, the center cone 2 can be rotationally driven, and the planetary roll group 5 can be freely rotated (FIG. 2B). Alternatively, the metal cylinder 10 can be non-rotated, the center cone 2 can be freely rotated, and the planetary roll group 5 can be rotationally driven. Further, the metal cylinder 10 can be rotated, the center cone 2 can be non-rotated, and the planetary roll group 5 can be freely rotated (FIG. 2C). Further, the metal cylinder 10 can be freely rotated, the center cone 2 can be rotationally driven, and the planetary roll group 5 can be non-rotated. Further, the metal cylinder 10 can be freely rotated, the center cone 2 can be non-rotated, and the planetary roll group 5 can be rotationally driven. Further, the metal cylinder 10 can be freely rotated, and both the center cone 2 and the planetary roll group 5 can be rotationally driven, and the rotational speeds of both can be made different. Any other combination is possible.

In the middle of tube expansion, it is assumed that the radius of the center cone 2 is Rc and the radius of the inner surface of the metal cylinder 10 is Rm at a constant axial position of the center cone central axis. Each planetary roll 4 is arranged so that the outer periphery of the planetary roll 4 is in contact with the inner periphery of the metal cylinder 10 and the outer periphery of the center cone 2, and no slip occurs between the planetary roll 4 and the metal cylinder 10 and between the planetary roll 4 and the center cone 2. Since the rotation speed of the metal cylinder 10 is Vm, the rotation speed of the center cone 2 is Vc, and the rotation (revolution) speed of the planetary roll group 5 is Vp, the following relationship is established.
Rm × Vm + Rc × Vc = (Rm + Rc) × Vp (1)
For example, in the example of FIG. 1, the metal cylinder 10 is not rotated, the planetary roll group 5 is freely rotated, and the center cone 2 is rotationally driven so as to rotate at the rotational speed Vc.

  By having the above relationship among the three members of the metal cylinder 10, the center cone 2, and the planetary roll group 5, the rotational speed around the center cone central axis is reduced between the metal cylinder 10 and the center cone 2. There will be a difference. This is because, when one of the three members except the one that freely rotates is rotated and the other is not rotated (fixed), or both are rotated, the rotational speeds of the two are made different.

The center cone 2 is integrally or divided in the axial direction. As shown in FIG. 1, when the center cone 2 is integrally formed in the axial direction, when the planetary roll 4 and the center cone 2 are rotated while being in contact with each other, the planetary roll 4 and the center are located at any location in the axial direction. It is preferable that there is no slip between the cone 2. As shown in FIG. 2, two locations A and B are selected in the axial direction, and the radius of the center cone 2 and the radius of the planetary roll 4 at each location are Rc _A , Rc _B , Rp _A and Rp _B. When
Rc _A / Rc _B = Rp _A / Rp _B (2)
If the tapered shapes of the center cone 2 and the planetary roll 4 are selected so that the center cone 2 and the planetary roll 4 are in the same position, the center cone 2 and the planetary roll 4 can rotate in contact with each other without slipping. In this case, the surface of the planetary roll group 5 in contact with the metal cylinder 10 has a conical shape, and the radius Rm of the conical shape is Rm _A = Rc _A + 2 × Rp _A (3-A) at each of A and B locations.
Rm _B = Rc _B + 2 × Rp _B (3-B)
It is represented by

When the distance between A and B is L, the taper angle θ of the expanded metal cylinder 10, the taper angle ψc of the center cone 2, and the taper angle ψp of the planetary roll 4 are as follows.
tan (θ / 2) = (Rm _B −Rm _A ) / L (4-1)
tan (ψc / 2) = (Rc _B −Rc _A ) / L (4-2)
tan (ψp / 2) = (Rp _B −Rp _A ) / L (4-3)

  In expanding the tube, the center cone 2 is moved in the axial direction with respect to the metal cylinder 10. In the example shown in FIGS. 1 and 3, the center cone 2 and the planetary roll group 5 are provided so as to move integrally in the axial direction, and the metal cylinder 10 is fixed in the axial direction during tube expansion and does not rotate around the axis. The planetary roll group 5 is in a freely rotating state, and the center cone 2 is driven to rotate.

  Before the pipe expansion, as shown in FIG. 3A, the pipe expansion jig 1 including the center cone 2 and the planetary roll group 5 is located on one end side in the axial direction of the metal cylinder 10, and the center cone 2 is connected to the center cone. While rotating in the rotation direction 21, the movement starts in the movement direction 22 and is inserted into the metal cylinder. As a result, the center cone 2 is moved in the axial direction with respect to the metal cylinder 10. The moving direction is a direction in which the front end 20 of the center cone moves forward. The metal cylinder 10 is held by the holder 7 at the axial end opposite to the tube expansion jig 1. When the tube expansion jig 1 is inserted into the metal cylinder while the center cone 2 is driven to rotate, the metal cylinder 10 is pushed and expanded to the tube expansion jig 1 whose outer shape is conical, as shown in FIG. In addition, tube expansion progresses sequentially. At this time, the metal cylinder is expanded into a shape as shown in FIG.

  As shown in FIG. 3C, when the axial movement of the tube expansion jig 1 is completed, the tube expansion of the metal cylinder 10 by the tube expansion jig 1 is completed, and the tube expansion jig 1 has a taper along the taper shape. A product after expansion can be obtained. At this time, the metal cylinder is expanded into a shape as shown in FIG.

  When the pipe is expanded, a difference in rotational speed around the central axis of the center cone is provided between the metal cylinder 10 and the center cone 2. As a result, a difference also occurs in the rotational speeds of the metal cylinder 10 and the planetary roll group 5. Therefore, when expanding the pipe, the position where the metal cylinder 10 and each planetary roll 4 are in contact with each other is not fixed to a fixed portion of the metal cylinder 10 but always changes. Therefore, the metal cylinder 10 does not have a nonuniform amount of extension in the circumferential direction, and any part in the circumferential direction extends in the same way. As a result, the tube expansion can be continued until the circumferential average elongation of the metal cylinder 10 reaches the elongation limit of the material, so that the tube expansion limit can be expanded as compared with the conventional expanding method.

  Further, since the metal cylinder 10 and the planetary roll 4 are in contact with each other so as not to slip in the circumferential direction, no scratches are generated on the inner surface of the metal cylinder 10.

  Further, the position where the planetary roll 4 is in contact with the metal cylinder 10 constantly varies in the circumferential direction, so that the metal cylinder 10 is not deformed into a polygonal shape.

  By the way, after the movement in the direction of advancing with the tip 10 of the center cone 2 as the head is completed and the tube expansion is completed, the rotation of the center cone 2 remains at the position when the tube expansion is completed, and the rotation drive is stopped. The circumferential position movement between the metal cylinder 10 and the planetary roll 4 may stop while the stress that the planetary roll 4 expands the pipe 10 is applied. In this case, the metal cylinder 10 may be deformed by the tension of the planetary roll 4 during the stop, and may be deformed into a polygonal shape with the position where the planetary roll 4 is present as a vertex. Therefore, in the present invention, it is preferable that the center cone 2 is moved in the reverse direction after the movement in the forward direction with the tip 10 of the center cone 2 as the head is completed, and the rotational drive is stopped there. Thereby, since rotation stops after the tension | tensile_strength between the metal cylinder 10 and the planetary roll 4 is cancelled | released, it can prevent that the metal cylinder 10 becomes a polygon.

  In the example shown in FIG. 3, when the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the metal cylinder 10 is fixed in the axial direction, and the center cone 2 is moved in the axial direction. On the other hand, the center cone 2 may be fixed in the axial direction, and the metal cylinder 10 may be moved in the axial direction.

  In the example shown in FIGS. 1 and 3, when the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the position of the center cone 2 and the planetary roll group 5 does not change relative to each other in the axial direction. Therefore, as the center cone 2 moves with respect to the metal cylinder 10 during the expansion of the tube, the planetary roll 4 also moves in a direction to be inserted deeper into the metal cylinder 10. During this movement, the planetary roll 4 gives a compressive stress to the metal cylinder 10 in the traveling direction of the planetary roll 4. If this stress is too strong, the metal cylinder 10 will be buckled in the axial direction during tube expansion. In the present invention, the higher the relative rotational speed between the metal cylinder 10 and the planetary roll 4, the smaller the axial compressive stress applied to the metal cylinder 10, thereby preventing the occurrence of buckling.

  By the way, the metal cylinder 10 is manufactured by rounding a metal plate and welding a joint portion. Therefore, as shown in FIG. 9D, the metal cylinder 10 has a welded portion 11 directed in the circumferential direction at one location in the circumferential direction. Usually, mushroom welding is used for welding, and the thickness of the welded portion 11 is formed so as to be as different as possible from the thickness of the base metal portion of the metal plate. It is thicker than the thickness of the part. And when the metal cylinder 10 and the planetary roll 4 move with relative rotational speed during the pipe expansion, the planetary roll 4 repeatedly passes through the welded part 11. Fatigue fracture will cause cracks in the welded part 11. In the present invention, fatigue failure of the welded portion 11 can be prevented by not excessively increasing the relative rotational speed between the metal cylinder 10 and the planetary roll 4. If the relative rotational speed between the metal cylinder 10 and the planetary roll 4 is 25 rpm or less, pipe expansion can be performed with less fatigue fracture of the welded portion. When the metal cylinder 10 is fixed and the center cone 2 is rotated, when the relative rotation speed between the metal cylinder 10 and the planetary roll 4 is 255 pm, the rotation speed of the center cone 2 is 50 rpm. A preferable relative rotational speed between the metal cylinder 10 and the planetary roll 4 is about 10 rpm.

  In the present invention, as shown in FIG. 4, a configuration in which the center cone 2 moves in the axial direction with respect to the planetary roll group 5 can be adopted. Since the center cone 2 is moved in the axial direction with respect to the planetary roll group 5, an axial position change occurs between the planetary roll group 5 and the center cone 2. The center cone 2 has a conical shape whose outer shape changes in the axial direction, and is arranged so that the outer periphery of each planetary roll 4 is in contact with the outer periphery of the center cone 2. Each planetary roll 4 needs to be movable in the radial direction from the central axis of the center cone in accordance with the change in axial position. In the example shown in FIG. 4, the planetary roll 4 is supported by the bearings 9 of the planetary roll support plates 6 disposed at both ends thereof. The bearing 9 of the planetary roll 4 is supported by the planetary roll support plate 6 so as to be movable, and the moving direction is a radial direction from the center cone central axis. In the example shown in FIG. 4, the two planetary roll support plates arranged at both ends of the planetary roll are connected to each other by support pillars 8. It is good also as a type which supports the planetary-roll support plate 9 of the front end side (left side of FIG. 4) only by the planetary-roll bearing 9 and the center cone shaft 3, without providing a support pillar. In FIG. 4A, the center cone 2 is disposed at a position before the start of tube expansion, and the planetary roll 4 is disposed at a position closest to the axis. In FIG. 4B, the center cone 2 is arranged at the position when the tube expansion is completed, and the planetary roll 4 is arranged at the position farthest from the axis.

  Further, as an application form of the structure shown in FIG. 4, as shown in FIG. 5, it is possible to adopt a shape that does not use the planetary roll support plate on the front end side. In the example shown in FIG. 5, an elastic ring 15 is provided on the tip 20 side so as to bundle the bearings 9 of the planetary roll. An elastic ring 15 was also provided on the side having the planetary roll support plate 6 so as to bundle the bearings 9 of the planetary roll. Thereby, the planetary roll 4 can maintain the position by being pressed against the center cone 2. In the case of the structure shown in FIG. 5, since the support pillar 8 is not required, the number of planetary rolls can be increased as compared with the case where the support pillar is provided.

  In the above apparatus and the method using the same, when the center cone 2 is moved in the axial direction with respect to the metal cylinder 10, the metal cylinder 10 and the planetary roll group 5 are configured such that their positions do not change relative to each other in the axial direction. Can do. Regarding the relative movement in the axial direction of the three members of the metal cylinder 10, the planetary roll group 5, and the center cone 2, the positions of the metal cylinder 10 and the planetary roll group 5 do not change from each other. It moves relative to the roll group 5 in the axial direction. Since the position of the metal cylinder 10 and the planetary roll group 5 does not change relative to each other, when the pipe is expanded into a tapered shape, no axial compressive stress is applied to the metal cylinder 10, and therefore the occurrence of buckling due to the compressive stress is prevented. Can do.

  At the start of tube expansion, as shown in FIG. 6A, the metal cylinder 10 is arranged outside the planetary roll group 5, and the center cone 2 is mostly or entirely outside the one end of the metal cylinder 10. Has been placed. The outer circumference of the planetary roll 4 is in contact with the outer circumference of the center cone 2, and the planetary roll 4 in the planetary roll group 5 is positioned closest to the central axis in the radial direction. When the expansion of the tube is started, the center cone 2 rotates in the center cone rotation direction 21 and moves in the movement direction 22 so that the center cone 2 is gradually inserted into the metal cylinder 10, and accordingly the radial direction of the planetary roll 4. The arrangement position spreads outward from the central axis in the radial direction. The metal cylinder 10 is in contact with the planetary roll 4 only at one end at the start of pipe expansion, and is expanded as the planetary roll 4 spreads outward as the pipe expands. As shown in FIG. 6 (b), the expansion of the tube ends when the center cone 2 is inserted deepest into the metal cylinder 10. In FIG. 6B, the center cone 2a and the planetary roll 4a at the start of expansion are indicated by a two-dot chain line, and the center cone 2b and the planetary roll 4b at the end of expansion are indicated by a solid line.

  Also in the present embodiment, it is preferable to move the center cone 2 in the reverse direction after the movement in the forward direction with the tip of the center cone 2 as the head is completed, and stop the rotational drive there. Thereby, since rotation stops after the tension | tensile_strength between the metal cylinder 10 and the planetary roll 4 is cancelled | released, it can prevent that the metal cylinder 10 becomes a polygon.

  In the embodiment shown in FIG. 3 described above, if the relative rotational speed between the metal cylinder 10 and the planetary roll group 5 is too slow, the metal cylinder may buckle during tube expansion. On the other hand, in the embodiment shown in FIG. 6, the metal cylinder 10 and the planetary roll group 5 do not have an axial relative speed, so there is no fear that the metal cylinder 10 buckles during tube expansion. Therefore, compared with the embodiment shown in FIG. 3, the relative rotational speed between the metal cylinder 10 and the planetary roll group 5 can be further reduced.

  In the example shown in FIGS. 4 to 6, the metal cylinder 10 held by the holder 7 is non-rotating (fixed), the planetary roll group 5 is freely rotating, and the center cone 2 is rotationally driven. Which of non-rotation, free rotation, and rotational drive can be selected as necessary.

  In the example shown in FIG. 7, the metal cylinder 10 is freely rotated, the planetary roll group 5 is not rotated, and the center cone 2 is rotationally driven. The planetary roll group 5 is fixed. When the movement in the moving direction 22 is started while rotating the center cone 2 in the center cone rotation direction 21, the metal cylinder 10 held by the holder 7 is expanded while being rotated in the metal cylinder rotation direction 23. Since the metal cylinder 10 rotates freely, the holder 7 that holds the metal cylinder 10 may be omitted.

  In all of the examples shown in FIGS. 1, 4, and 5, the center cone 2 is formed as an integral type. On the other hand, as shown in FIG. 8, the center cone 2 can be divided into a plurality of parts in the axial direction. In this case, a plurality of center cones are attached to the center cone shaft, and only one of the center cones is restrained in the rotational direction by the center cone shaft 3 and is called a restrained center cone 2a. An unconstrained center cone 2b is preferably arranged so as to be freely rotatable with respect to the cone shaft 3. For example, when the metal cylinder 10 is not rotated (fixed), the planetary roll group 5 is freely rotated, and the center cone 2 is rotationally driven, when the center cone shaft 3 is rotationally driven, only the constraining center cone 2a is rotationally driven accordingly. The As the constraining center cone 2a rotates, the planetary roll 5 rotates around the center cone central axis so as to satisfy the equation (1). At this time, since the non-restraining center cone 2b other than the restraining center cone 2a is not restrained by the center cone shaft 3, the rotational speed of the unconstrained center cone 2b may be different from the rotational speed of the restraining center cone 2a. As a result, since it is not necessary to satisfy the equation (2), the diameter of the planetary roll 4 need not satisfy the equation (3). That is, the form of the change in the axial radius of the planetary roll 4 can be freely selected. As shown in FIG. 8, the planetary roll 4 can be a cylindrical planetary roll without changing the radius of the planetary roll 4 in the axial direction. The surface of each center cone in contact with the metal cylinder may have a conical shape or may have a shape curved in the axial direction.

Example 1
The diameter of the metal cylinder 10 before the pipe expansion is 80 mm and the length is 80 mm. The present invention was applied when the metal cylinder 10 was expanded into a conical shape with a taper angle of 15.5 °.

  The tube expansion jig 1 shown in FIG. 1 was used. The number of the planetary rolls 4 is 15, and an integral one is used as the center cone 2, the taper angle ψc of the center cone 2 is 12.33 °, and the taper angle of the planetary roll 4 is 1.6 °. The length of the center cone 2 and the planetary roll 4 is about 70 mm. When expanding the pipe, the metal cylinder 10 was held by the holder 7, the metal cylinder 10 held by the holder 7 was non-rotating, the planetary roll group 5 was freely rotating, and the center cone 2 was rotationally driven. The center cone shaft 3 is connected to the rotation drive device 30. The outer peripheral side outer diameter (diameter) of the planetary roll group 5 is 80 mm at the site A on the tip side of the center cone shown in FIG. 2 and 99.1 mm at the site B 70 mm away from the site A.

  As the metal cylinder 10, five kinds of materials were selected as shown in Table 1. Ten kinds of thicknesses of 0.18 mm to 0.27 mm were prepared for each material. These metal plates were rolled and the seam portion was mushroom-welded to form a welded portion 11, which was a metal cylinder having a diameter of 80 mm and a length of 80 mm (FIG. 9D).

  The metal cylinder 10 before the pipe expansion was held by the holder 7, and the pipe expansion was performed using the pipe expansion jig 1 shown in FIG. The rotation speed of the center cone 2 was set to 20 rpm, the holder 7 was fixed, and the center cone 2 was inserted into the metal cylinder at a feed speed of 4 to 5 mm / sec to expand the tube. The relative rotational speed of the planetary roll group 5 with respect to the metal cylinder 10 (non-rotating) is 10 rpm. If a crack occurred in the welded part 11 during the pipe expansion, the pipe expansion was terminated there. At the tube end where the tube expansion jig 1 was inserted, the diameter expansion rate of the metal cylinder until the fracture occurred was the maximum tube expansion rate and expressed in%. Table 2 shows the maximum tube expansion ratio (%) by material and thickness.

  Next, among the materials shown in Table 1, T-2 · 1/2 is used, the plate thickness is 0.2 mm, the rotational speed of the center cone 2 is changed in the range of 20 to 417 rpm, and the holder 7 is fixed. Then, the center cone 2 was inserted into the metal cylinder at a feed rate of 10 to 15 mm / sec, and the tube was expanded. The other conditions are the same as in Table 2 above. The results are shown in Table 3. In the range of the rotation speed of the center cone of 20 to 102 rpm, a good tube expansion result with a maximum tube expansion rate of 20% or more could be obtained.

  For any material and plate thickness, the metal cylinder did not buckle. As for the quality after the tube expansion, the cross-sectional shape was not a polygon but a perfect circle, and no scratches were generated on the inner surface.

  When the conventional expanding method shown in FIG. 10A is used, if the same processing as in the above embodiment is performed on the material T-2 · 1/2, the maximum tube expansion ratio is about 0.2 mm in plate thickness. At most, it is about 7%. On the other hand, it is clear that the processable range of the present invention is widened.

(Example 2)
When expanding the metal cylinder in the same manner as in Example 1, the tube expansion jig 1 shown in FIG. 5 was used. The planetary roll 4 has a number of 15, and its length is as long as about 140 mm. During the expansion, the center cone 2 moves in the axial direction, but the planetary roll group 5 does not move in the axial direction. Other specifications are the same as in the first embodiment.

  As the metal cylinder 10, a material having the material T-2 · 1/2 in Example 1 and a plate thickness of 0.2 mm was used. Tube expansion was performed by setting the rotation speed of the center cone 2 to 10 rpm and the feed speed of the center cone 2 to the planetary roll group 5 to 100 mm / second. As a result, the maximum tube expansion rate was 23%. As for the quality after the tube expansion, the cross-sectional shape was not a polygon but a perfect circle, and no scratches were generated on the inner surface.

It is a figure which shows an example of the pipe expansion jig of this invention, (a) is a top view, (b) is BB arrow sectional drawing, (c) is CC arrow sectional drawing, (d) is D It is -D arrow sectional drawing. It is a figure which shows the shape and motion of the pipe expansion jig of this invention, (a) is a side view, (b) (c) is sectional drawing. It is a figure which shows the condition which expands using an example of the pipe expansion apparatus of this invention, (a) is a figure which shows the time of pipe expansion start, (b) is in the middle of pipe expansion, (c) is a figure which shows the time of pipe expansion completion. It is a figure which shows an example of the pipe expansion jig of this invention, (a) is a figure which shows the time of pipe expansion start, and (b) shows the time of pipe expansion completion. It is a figure which shows an example of the pipe expansion jig of this invention, (a) is a figure which shows the time of pipe expansion start, and (b) shows the time of pipe expansion completion. It is a figure which shows the condition which expands using an example of the pipe expansion apparatus of this invention, (a) is a figure which shows the time of pipe expansion start, and (b) shows the time of pipe expansion completion. It is a figure which shows the condition which expands using an example of the pipe expansion apparatus of this invention. It is a figure which shows an example of the pipe expansion apparatus of this invention. Among the expansion conditions of the metal cylinder, (a) is before expansion, (b) is during expansion, (c) is a view showing the end of expansion, and (d) is a view showing the metal cylinder. It is a fragmentary figure which shows the pipe expansion method by the conventional expand system, (a) is the case where the arc surface radius of a segment is equal to the metal cylinder radius after tube expansion, (b) is the metal cylinder radius before the tube expansion of the segment arc surface radius Is equal to

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tube expansion jig 2 Center cone 3 Center cone axis | shaft 4 Planetary roll 5 Planetary roll group 6 Planetary roll support plate 7 Holder 8 Support pillar 9 Bearing 10 Metal cylinder 11 Welded part 15 Elastic ring 20 Tip 21 Center cone rotation direction 22 Movement direction 23 Rotating direction of metal cylinder 30 Rotation drive device 40 Segment 41 Arc surface 42 Segment corner contact portion 43 Segment center contact portion 44 A portion 45 between two edge portions of one segment 45 A portion between edge portions of adjacent segments

Claims (8)

A tube expansion device for expanding a metal cylinder having a wall thickness / diameter ratio of 0.0034 or less, which is a side surface portion of a metal can, which is formed by welding a seam portion of a metal plate. Has a tube expansion tool,
The tube expansion jig has a center cone and a planetary roll group disposed on the outer periphery thereof,
The center cone has a conical shape whose outer diameter changes in the axial direction of the center cone, the center cone is integrated or divided into a plurality of parts in the axial direction, and the end portion on the side where the outer diameter of the center cone is small is referred to as a tip.
The planetary roll group has planetary rolls arranged in a range of 8 to 15 so as to surround the outer periphery of the center cone, and each planetary roll has a tapered shape at two arbitrary positions A and B in the axial direction. When the radius of the center cone is Rc _A and Rc _B and the radius of the planetary roll is Rp _A and Rp _B , the relationship of the following equation (2) is established, and each planetary roll is interlocked when rotating around the center cone. The surface of each planetary roll that is in contact with the inner circumference of the metal cylinder and the outer circumference of the center cone is arranged on the outer diameter of each planetary roll. Is a conical shape that changes in the axial direction,
The center cone is moved in the axial direction with respect to the metal cylinder while providing a difference in rotational speed around the center cone center axis between the metal cylinder and the center cone, and the moving direction is the direction in which the tip of the center cone is advanced. A tube expansion device characterized by being.
Rc _A / Rc _B = Rp _A / Rp _B (2)   2. The tube expansion device according to claim 1, wherein when the center cone is moved in the axial direction with respect to the metal cylinder, the position of the center cone and the planetary roll group does not change relative to each other in the axial direction.   Furthermore, it has a holder holding a metal cylinder, The pipe expansion apparatus of Claim 1 or 2 characterized by the above-mentioned.   The tube expansion device according to claim 3, wherein the holding of the metal cylinder by the holder can be released after the metal cylinder contacts the planetary roll.   4. The tube expansion device according to claim 1, wherein during the tube expansion, the metal cylinder is in contact with only the planetary roll of the members constituting the tube expansion jig. 5. A tube expansion method for expanding a metal cylinder having a thickness / diameter ratio of 0.0034 or less using a tube expansion jig, which is a side surface portion of a metal can, which is formed by welding a metal plate and welding a seam portion. Because
The tube expansion jig has a center cone and a planetary roll group disposed on the outer periphery thereof,
The center cone has a conical shape in which the outer diameter changes in the axial direction, the center cone is integrated or divided into a plurality of parts in the axial direction, and the end portion on the side where the outer diameter of the center cone is small is referred to as a tip.
The planetary roll group has planetary rolls arranged in a range of 8 to 15 so as to surround the outer periphery of the center cone, and each planetary roll has a tapered shape at two arbitrary positions A and B in the axial direction. When the radius of the center cone is Rc _A and Rc _B and the radius of the planetary roll is Rp _A and Rp _B , the relationship of the following formula (2) is established. When each planetary roll rotates concentrically with the center cone, Rotating together, arranged so that the outer circumference of each planetary roll is in contact with the outer circumference of the center cone, the surface of the planetary roll group in contact with the metal cylinder is a conical shape whose outer diameter changes in the axial direction,
The inner periphery of the metal cylinder is the outer periphery of the planetary roll and is brought into contact with the tapered portion , and the center cone is moved in the axial direction with respect to the metal cylinder while providing a difference in rotational speed between the metal cylinder and the center cone. The tube expansion method is characterized in that the moving direction is a direction of advancing with the tip of the center cone as the head.
Rc _A / Rc _B = Rp _A / Rp _B (2)   The tube expansion method according to claim 6, wherein when the center cone is moved in the axial direction with respect to the metal cylinder, the center cone and the planetary roll group do not change their positions in the axial direction. 8. The tube expansion method according to claim 6, wherein the metal cylinder is in contact with only the planetary roll among the members constituting the tube expansion jig during the tube expansion.

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