JP4443959B2 - Cutting method of metal sheet drum - Google Patents

Description

  The present invention relates to a method for cutting a metal thin plate drum, in which a drum formed in a cylindrical shape by a metal thin plate is cut at a predetermined width in the circumferential direction.

  For example, in a power transmission belt employed in a continuously variable transmission, a laminated ring formed by laminating a plurality of metal ring members is used in order to bind together a plurality of elements arranged in a ring shape. It is done. The metal ring constituting this type of laminated ring is formed by cutting a cylindrical drum formed by welding both ends of a rectangular metal thin plate into a ring shape with a predetermined width.

  Conventionally, when forming a metal ring by cutting a cylindrical drum every predetermined width, one end of the drum is clamped and supported, and a rotating grindstone is pressed from the outside of the other end of the drum. It is known that cutting is performed by moving the grindstone in the circumferential direction of the drum. However, when the drum is cut using a grindstone, a grinding allowance corresponding to the width of the grindstone is required, so the yield of metal rings obtained from one drum is low. Further, when the drum is cut using a grindstone, there is a problem that wastewater treatment is complicated when the worn grindstone is polished.

Therefore, as can be seen in Patent Document 1 below, a method is known in which the drum is cut using a pressing blade tool instead of the grindstone. However, in this case, no burr is generated at the corner edge portion on the inner peripheral side of the metal ring, but a relatively large burr is generated at the corner edge portion on the outer peripheral side, and shaping processing such as barrel polishing performed after cutting. There is an inconvenience that it takes a long time. Further, in Patent Document 1, there is a method in which burrs are not generated at the corner edge portions on both the inner peripheral side and the outer surface side by pressing a cutting blade tool on both sides of the inner surface side and the outer surface side of the drum. Although shown, there is a risk that both cutting tools come into contact with each other after the drum has been cut and the cutting tools are damaged.
JP 2001-241512 A

  In order to eliminate such inconvenience, the present invention can improve the manufacturing efficiency by shortening the time for shaping the cutting edge of the metal ring cut from the thin metal drum, and the drum can have a predetermined width. It is another object of the present invention to provide a method for cutting a metal thin plate drum that can be cut with high accuracy and high yield, and can further prolong the life of a blade.

  In order to achieve such an object, the present invention holds a drum formed of a thin metal plate in a cylindrical shape by extrapolating it to a cylindrical holder that can be driven to rotate. One end of the drum is held on the holder. It is fixed and rotated together with the holding tool, and a pressing blade is pressed against the outer peripheral surface of the drum at a predetermined width from the non-fixed side of the other end of the drum, and the drum is cut in the circumferential direction to endless belt-shaped metal A method of cutting a metal thin plate drum forming a ring, wherein the pressing blade has a blade angle in a range of 50 to 90 °, and corresponds to a cutting position of the pressing blade on an outer peripheral surface of the holding tool. An annular groove portion formed at a predetermined interval is formed, the groove portion is formed in a V shape in a sectional view, and the interval dimension between the upper edges of the inner walls facing each other is the plate thickness of the drum. 15-30 times the size and located in the central part of the groove The depth dimension of the deep part is 1 to 3 times the plate thickness dimension of the drum, and both inner side walls of the groove part have a radius of curvature 15 to 50 times the plate thickness dimension of the drum. The position of the tip of the pressing blade tool when cutting into the groove through the drum from the center of the interval between the upper edges of the inner walls of the groove facing each other. It is characterized in that it is close to the non-fixed side of the drum within a range of a distance of 1/3 of the thickness of the drum.

  When a metal thin plate drum is cut according to the present invention, first, the press cutting tool cuts the drum while pressing the drum into the groove. At this time, a part of the drum which is pressed by the cutting tool is gently bent along the curved surface of the inner wall of the groove. In the portion where the cutting tool is cut, a meat flow occurs in the direction away from the cutting tool. Accordingly, the side that has not yet been cut toward the blade tip is stretched, the thickness of the portion toward the blade tip is locally reduced, and a constriction that is indented and deformed toward the blade tip is formed. And the drum is cut | disconnected without contacting the deepest part of a groove part in the state which left the constriction shape. The occurrence of burrs at the cutting edge can be reduced due to the remaining constriction.

  The blade angle of the cutting tool and the shape of the groove of the holding tool are based on various tests by the inventors. Specifically, the following was found by the test. That is, regarding the blade angle of the cutting blade being 50 to 90 °, if the blade angle is larger than 90 °, the meat flow rate that is pushed away on both sides when the blade is cut into the drum is increased, and the blade is warped. And ripples occur. When the blade angle is smaller than 50 °, the blade is too sharp and the durability is lowered due to the occurrence of blade spillage.

  Moreover, about the space | interval dimension between the upper edges of both the inner walls of a groove part being 15-30 times of the plate | board thickness dimension of a drum, when it is narrower than 15 times, when a drum is pressed with a blade tool, a drum will be a groove part. It cannot bend gently along the curved surface of the inner wall, and burrs are generated along the inner wall of the groove after cutting. When the drum is wider than 30 times, when the drum is pressed by the cutting tool, the drum contacts the deepest portion of the groove before being cut, and sufficient necking does not occur.

  Moreover, about the depth dimension of the deepest part located in the center of a groove part being 1 to 3 times the plate | board thickness dimension of a drum, when the drum is pressed with a cutting tool if it is shallower than 1 time, a drum will be cut | disconnected. Before contact, it touches the deepest part of the groove and does not generate sufficient necking. When it is deeper than 3 times, it becomes difficult to form the curved surface having a radius of curvature of 15 to 50 times the plate thickness of the drum.

  Furthermore, when the curved surface has a radius of curvature of 15 to 50 times the plate thickness dimension of the drum, if it is smaller than 15 times, when the drum is pressed by the cutting tool, the drum is brought into the curved surface of the inner wall of the groove. Accordingly, burrs along the inner wall of the groove portion are generated after cutting. If it is larger than 50 times, when the drum is pressed by the cutting tool, it comes into contact with the deepest part of the groove before the drum is cut, and sufficient necking does not occur.

  From the test results as described above, the pressing blade employed in the present invention has a blade angle in the range of 50 to 90 °, and the upper edge of both inner side walls of the groove of the holder. Is 15 to 30 times the plate thickness of the drum, the depth of the deepest part is 1 to 3 times the plate thickness of the drum, and the curvature radius of the curved surface is 15 to 15 times the plate thickness of the drum. 50 times.

  Accordingly, by adopting the shape of the cutting tool and the groove portion described above, it is possible to form a constriction at the cutting position of the drum, so that there is very little burr at the cutting edge, and shaping processing such as barrel polishing or brush polishing is performed. This can be done in a short time, and the production efficiency can be improved. In addition, the metal thin plate drum can be cut to a predetermined width with a good yield, and furthermore, the contact of the tip of the blade with the deepest portion of the groove is extremely small, so the life of the blade can be extended.

  By the way, when a metal ring is formed from the drum by the cutting tool, the drum is cut off on both sides of the cutting tool. At this time, a cutting edge formed on the non-fixed side of the drum with respect to the cutting tool (cutting edge of the cut metal ring) and a cutting edge formed on the fixed side of the drum with respect to the cutting tool (holding tool) The shape is slightly different from the cutting edge of the drum fixed to the drum. That is, when the drum is cut along the groove by the pressing blade, the cutting edge of the drum is formed by the first cutting inclined surface that is inclined following the blade surface of the pressing blade and the groove. A second cutting inclined surface having an inclined shape due to the constricted portion and a cutting top where the tip of the first cutting inclined surface and the tip of the second cutting inclined surface intersect are formed. Here, when the cutting edge formed on the non-fixed side of the drum is compared with the cutting edge formed on the fixed side of the drum, the first and second cutting inclined surfaces on the fixed side of the drum are the drums. The position of the cutting top on the fixed side of the drum is closer to the center of the plate thickness than the non-fixed side of the drum. The difference in the shape of the cutting edge is that the cutting edge immediately separates from the cutting tool after cutting on the non-fixed side of the drum, while the cutting edge is cut off from the groove after cutting on the fixed side of the drum. This occurs because a part of the cutting edge is scraped off when the edge contacts the cutting tool. When such a difference in cutting edge occurs, the shape of the cutting edge on both sides of the cut metal ring will be different, and barrel cutting or brush polishing for adjusting the cutting edge to a predetermined shape, etc. There is a possibility that the processing time cannot be shortened.

  Therefore, the present inventor conducted various tests, and the position of the tip of the press cutting blade tool at the time of cutting progressed from the center of the interval dimension of the upper edges of the inner walls facing each other toward the non-fixed side of the drum. Due to the influence of the shape of the groove, the first cutting inclined surface and the second cutting inclined surface of the cutting edge formed on the non-fixed side of the drum become smaller, and the position of the cutting top portion is thicker than the non-fixed side of the drum. I knew that it would be closer to the center. Further, the position of the tip of the pressing blade at the time of cutting exceeds the distance of 1/3 of the plate thickness of the drum from the center of the distance between the upper edges of the inner walls facing each other of the groove, and the drum is not fixed. When approaching the side, it has become clear that the neck cannot be sufficiently constricted at the cutting edge on the non-fixed side of the drum, and the cutting accuracy cannot be maintained.

  Based on this, in the present invention, the position of the tip of the pressing blade tool at the time of cutting is set to 1/3 of the plate thickness dimension of the drum with respect to the center of the interval dimension of the upper edges of the inner walls facing each other. The distance between the cutting edge formed on the non-fixed side of the drum and the cutting edge formed on the fixed side of the drum is extremely small by being closer to the non-fixed side of the drum within the distance range of It is possible to perform barrel polishing or brush polishing for adjusting the cutting edge into a predetermined shape in a short time.

  Furthermore, in the present invention, the groove portion of the holder includes a flat portion formed flat so that the deepest portion has a constant depth between both inner side walls. By doing so, the cutting edge of the drum after cutting becomes a shape that follows the flat portion of the groove portion, and the constriction can be formed more reliably, and in particular, it is formed on the non-fixed side of the drum due to the influence of the flat portion. In both of the cutting edge and the cutting edge formed on the fixed side of the drum, the position of the cutting top can be formed closer to the center of the drum thickness. Then, by positioning the cutting top portion at the center of the plate thickness, the first cutting inclined surface and the second cutting inclined surface are approximated, whereby the shaping amount by polishing can be reduced, and the drum can be cut. The shaping process by barrel polishing or brush polishing on the edge can be performed in a shorter time.

  Further, in the present invention, when the drum is cut, the position of the tip of the pressing blade when the cutting blade is most deeply entered into the groove is determined from the deepest portion of the groove to the drum. It is characterized in that the distance is 0.2 to 0.4 times the plate thickness dimension.

  Furthermore, the present inventor has found through various tests that the shape of the cutting edge described above changes according to the depth at which the pressing blade enters the groove when the drum is cut. According to this, when the distance between the tip of the press cutting blade and the deepest portion of the groove is smaller than 0.2 times the plate thickness of the drum, it takes a long time until the blade is completely removed from the groove after cutting, Since the contact time between the cutting edge on the fixed side of the drum and the cutting tool becomes long, there is a difference in the shape between the cutting edge formed on the non-fixed side of the drum and the cutting edge formed on the fixed side of the drum. Arise. Also, if the distance between the tip of the press cutting tool and the deepest part of the groove is larger than 0.4 times the plate thickness dimension of the drum, the approach of the tool to the groove becomes shallow, and the pressing force of the drum against the inner wall of the groove is reduced. Since it is lowered, the constriction cannot be sufficiently formed. From this, in the present invention, the tip of the pressing blade tool is advanced from the deepest part of the groove part to a position having a distance of 0.2 to 0.4 times the plate thickness of the drum. The metal ring can be reliably cut and formed with a very small difference in shape between the cutting edge formed on the non-fixed side and the cutting edge formed on the fixed side of the drum.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory sectional view showing a cutting tool and a groove, FIG. 3 is an explanatory view showing a drum cutting process in this embodiment, and FIG. FIG. 5 is an explanatory sectional view showing a part of the drum cutting process, FIG. 5 is an explanatory sectional view showing a part of the drum cutting process, and FIG. 6 is an explanatory sectional view showing the cutting edge shape of the conventional drum for comparison. FIG. 7, FIG. 7 is an explanatory sectional view showing a cutting edge shape formed on the drum according to the present embodiment, FIG. 8 is an explanatory view showing another holding tool, and FIG. 9 is a case where the holding tool of FIG. 8 is adopted. It is explanatory sectional drawing which shows an apparatus form.

  The cutting device 1 of this embodiment shown in FIG. 1 manufactures a metal ring of a belt for a continuously variable transmission (not shown) by cutting a metal drum W into a ring shape for each predetermined width. The drum W is formed by forming a rectangular flat thin plate of maraging steel into a cylindrical shape, and then welding both ends of each other by abutting each other.

  As shown in FIG. 1, the cutting device 1 of the present embodiment includes a drum holding means 2 that holds the drum W and a cutting means 3 that cuts the drum W.

  The drum holding means 2 includes a support shaft 4 that is rotated by a rotation driving means (not shown), and a holder 5 that is connected to the support shaft 4 and holds the drum W on the outer periphery thereof and abuts against the inner surface of the drum W. And.

  As shown in FIG. 1, the holder 5 is formed in a columnar shape with metal, and has a plurality of groove portions on the outer periphery thereof along a cutting position of the drum W (a cutting position of a press cutting blade 7 described later). 8 are formed at predetermined intervals. The drum W held by the holder 5 is fixed so that one end is clamped by a plurality of clamp means 4 a provided on the support shaft 4 and rotates integrally with the holder 5.

  As shown in FIG. 2, the groove portion 8 formed in the holder 5 is formed in a generally V shape in sectional view. The groove portion 8 will be described in more detail. In the present embodiment, curved surfaces 10 are formed on the inner side walls 9 on both sides of the groove portion 8 so as to protrude inward of the groove portion 8. The distance a between the upper edges 9a and 9b of the inner wall 9 on both sides of the groove 8 is about 20 times the plate thickness dimension b of the drum W (may be 15 to 30 times). Further, the depth dimension c of the deepest part 11 of the groove part 8 is about twice (thus 1 to 3 times) the plate thickness dimension b of the drum W, and the curvature radius of the curved surface 10 of the inner wall 9 is further increased. Is about 30 times the plate thickness dimension b of the drum W (may be 15 to 50 times). Further, the deepest portion 11 is formed flat across the inner side walls 9 on both sides. The width dimension d of the flat portion 11a is set according to the shape of the cutting edge when the drum W is cut, as will be described in detail later.

  As shown in FIG. 1, the cutting means 3 includes a rotating shaft 12 and a disk-shaped pressing blade 7 that is integrally supported by the rotating shaft 12. Although not shown, the cutting means 3 includes an advancing / retreating movement means for advancing and retracting the press cutting tool 7 toward the drum W and moving it in the axial direction of the drum W. Further, the press cutting tool 7 is rotatably provided by a rotating shaft 12. Since the press cutting tool 7 is rotatable, the press cutting tool 7 is rotated by contact with the drum W rotated by the drum holding means 2, and the drum W can be pressed by the entire circumference of the press cutting tool 7. It is said. The drum W is cut by the cutting blade 7 of the cutting means 3 from the non-fixed side of the drum W (the side not fixed to the holding tool 5 by the clamp means 4a) every predetermined width. The pressing blade 7 may be rotationally driven by a rotational driving means (not shown) via the rotational shaft 12.

  The press cutting tool 7 is made of a metal whose hardness is higher than that of the maraging steel, for example, a cemented carbide, a high speed steel, and the like, and the cutter angle θ may be 60 ° (50 to 90 ° as shown in FIG. 2). ).

  When forming the metal ring by cutting the drum W into a ring by the apparatus 1 having the above configuration, first, as shown in FIG. 1, the drum W held by extrapolation on the holder 5 is rotated by the drum holding means 2, and then The cutting means 3 approaches the drum W, and the pressing blade 7 cuts into the drum W. At this time, since the drum W is rotating, the pressing blade 7 is cut over the entire circumference of the drum W, and a metal ring having a predetermined width is obtained.

  Here, the operation when the press cutting tool 7 cuts into the drum W will be described. First, as shown in FIG. 3A, when the press cutting tool 7 is pressed against the drum W, the press cutting tool 7 cuts into the outer peripheral surface of the drum W, thereby starting cutting. At this time, as shown in FIG. 2, the cutting position of the tip of the press cutting tool 7 is set to a plate thickness dimension b of the drum W from the center s of the distance dimension a between the upper edges 9 a and 9 b of the inner wall 9 on both sides of the groove 8. Of the drum W is closer to the non-fixed side (rightward in the figure).

  As shown in FIG. 3A, the drum W pressed by the pressing blade 7 is bent along the curved surface 10 of the inner wall 9 of the groove 8. At this time, the drum W is in a state of being separated from the deepest portion 11 of the groove portion 8 or instantaneously even if it contacts the deepest portion 11.

  Next, as shown in FIG. 3B, when the cutting blade 7 is cut into the drum W and the tip of the cutting blade 7 approaches the inner peripheral surface side of the drum W, the inner peripheral surface of the drum W. On the side, a constriction X that is recessed and deformed toward the tip of the press cutting blade 7 is formed. As shown in FIG. 4, the constriction X causes a metal flow in the direction away from the press cutting blade 7 due to the cutting of the press cutting tool 7, and accordingly, the inner circumference of the drum W that has not been cut. It is formed by stretching the surface side and locally reducing the thickness of the portion to which the tip of the pressing blade 7 is directed. Accordingly, the drum W is bent along the curved surface 10 of the inner wall 9 of the groove 8 so that a flesh flow is generated in the metal of the drum W at this time, and the drum W is smoothly generated so that the constriction X is generated smoothly. Each dimension of the groove portion 8 is set so as to be separated from the deepest portion 11 of the groove portion 8. That is, the inventor conducted various tests on the relationship between the dimensions of the groove 8 and the occurrence of the constriction X, and as a result, as shown in FIG. 2, the upper edge 9a of the inner wall 9 on both sides of the groove 8 is obtained. , 9b is set to 15 to 30 times the plate thickness dimension b of the drum W, the depth c of the deepest portion 11 of the groove 8 is set to 1 to 3 times the plate thickness dimension b of the drum W, and the inner side It has been found that when the radius of curvature of the curved surface 10 of the wall 9 is 15 to 50 times the plate thickness dimension b of the drum W, the constriction X can be reliably generated. In this embodiment, based on this, the distance a between the upper edges 9a and 9b of the inner wall 9 on both sides of the groove 8 is about 20 times the plate thickness dimension b of the drum W, and the depth of the deepest part 11 of the groove 8 is. A sufficient constriction X is generated with c being about twice the plate thickness dimension b of the drum W and the curvature radius of the curved surface 10 being about 30 times the plate thickness dimension b of the drum W.

  Subsequently, as shown in FIG. 3C, the drum W is cut by the pressing blade 7 in a state where the constriction X is separated from the deepest portion 11 of the groove portion 8. At this time, the position of the tip of the press cutting tool 7 is set so as to be located at a distance of 0.2 to 0.4 times the plate thickness dimension of the drum from the deepest portion 11 of the groove 8. . As a result, the cutting is completed without the press cutting tool 7 coming into contact with the deepest portion 11 of the groove 8. If the blade angle of the press cutting blade 7 is larger than 90 °, the meat flow rate pushed away on both sides when the drum W is cut into the drum W excessively increases, and the drum W is warped and wavy. If the blade angle is smaller than 50 °, the tip of the press-cutting blade 7 is too sharp, and the durability is lowered due to the occurrence of blade spillage or the like. Therefore, the blade angle of the press cutting blade 7 is preferably 50 to 90 °, and in this embodiment, the blade angle of the press cutting blade 7 is set to 60 ° based on this. Furthermore, when the cutting is completed, the position of the tip of the pressing blade 7 is such that the distance h between the tip of the pressing blade 7 and the deepest portion 11 of the groove 8 is less than 0.2 times the plate thickness dimension b of the drum. Since it takes a long time until the cutting tool 7 is completely removed from the groove 8 after cutting, the contact time between the cutting edge on the fixed side of the drum W and the cutting tool 7 becomes long. There is a difference in the shape between the cut edge and the cut edge formed on the fixed side of the drum W. Further, when the distance between the tip of the pressing blade 7 and the deepest portion 11 of the groove 8 is larger than 0.4 times the plate thickness dimension b of the drum W, the blade 7 enters the groove 8 shallowly, and the groove 8 Since the pressing force of the drum W against the inner wall 9 is reduced, the constriction X cannot be sufficiently formed. From this, the position of the tip of the pressing blade 7 at the time of completion of cutting is set at a position that is 0.2 to 0.4 times as thick as the plate thickness dimension b of the drum W from the deepest portion 11 of the groove 8. It is preferable that the metal ring be reliably reduced by extremely reducing the difference in shape between the cutting edge formed on the non-fixed side of the drum W and the cutting edge formed on the fixed side of the drum W. Can be cut and formed.

  Then, as shown in FIG. 3 (d), the pressing blade 7 moves backward and separates from the drum W. Since the constriction X is generated on the inner peripheral surface side of the drum W, the drum W is cut at the corner edge on the inner peripheral surface side, leaving a curved shape due to the constriction X, and a metal ring is formed. Further, as shown in FIG. 2, the cutting position of the tip of the press cutting tool 7 is changed from the center s of the interval dimension a between the upper edges 9a, 9b of the inner wall 9 on both sides of the groove 8 to the plate thickness dimension b of the drum W. By being close to the non-fixed side of the drum W (to the right in the figure) within the range f of 1/3 of the distance, the fixed side of the drum W when the press cutting blade 7 moves backward and separates from the drum W. Even if the cutting edge of the drum contacts the press cutting tool 7 and a part of the cutting edge is scraped off, the shape of the cutting edge on the non-fixed side of the drum W (the edge of the separated metal ring) is formed. The difference is very small.

The situation at this time will be described in more detail. As shown in FIG. 5, when the cutting blade 7 is separated from the groove portion 8, the metal ring Y separated on the non-fixed side of the drum W becomes movable. and has its cutting edge Z ₁ is separated from the straw cutter blade 7 immediately after the metal ring Y is disconnected. However, the cutting edges Z ₂ of the fixed side of the drum W is not be separated from the immediately straw cutter blade 7 to one end of the drum W is fixed, until straw cutter blade 7 moves away from the groove 8 It will be in the state which contacted the press cutting tool 7. FIG. For this, as shown in the case of conventional for comparison in Figure 6, a portion of the cutting edge Z ₂ of the fixed side of the drum W is scraped by straw cutter blade 7, the cutting of the stationary side of the drum W and edge Z _2, are greatly different shapes of the cutting edges Z ₁ unfixed side of the drum W. Therefore, in the present embodiment, the cutting position of the tip of the press cutting blade 7 is set close to the non-fixed side (to the right in the figure), so that the cutting edge Z on the non-fixed side of the drum W is shown in FIG. The formation region of ₁ is shortened, and the shapes of both cutting edges Z ₁ and Z ₂ are formed to be very approximate.

Therefore, according to this embodiment, as shown in FIG. 7, very close to the cutting edge Z ₁ unfixed side of the cutting edge Z ₂ and the metal ring Y and drums W of the fixed side of the drum W Further, since the burr X does not cause burrs at both cutting edges Z ₁ and Z _{2 due} to the constriction X, the time required for the shaping process such as barrel polishing or brush polishing performed in the subsequent process is shortened. be able to. Further, by adopting the cutting with the press cutting tool 7, it is possible to improve the yield of the metal ring Y obtained from the drum W without cutting off the cutting edges Z ₁ and Z ₂ as compared with the case of using a grindstone. Can do.

  Here, if the width dimension d of the flat part 11a formed in the deepest part 11 of the groove part 8 described above is described, when the cutting blade 7 cuts the drum W as shown in FIG. The constriction X is cut in a state of being separated from the deepest portion 11 of the groove portion 8, and the portion of the cutting edge that is in contact with the pressing blade tool 7 is shaped so as to follow the pressing blade tool 7 by receiving the cutting pressure by the pressing blade tool 7. It inclines (first cutting inclined surface 15). On the other hand, at this time, the portion of the cutting edge that is in contact with the groove portion 8 is deformed by being pressed against the flat portion 11a, and is inclined so as to follow the flat portion 11a (second cutting inclined surface 16). As a result, the constriction X is extended as much as the second cutting inclined surface 16 is formed following the flat portion 11a, and the position of the cutting top portion 14 can be brought closer to the center side of the plate thickness dimension b. .

  Then, as shown in FIG. 7, the width dimension e of the second cutting inclined surface 16 when the position of the cutting top portion 14 is located at the center of the plate thickness dimension b is determined in advance, and as shown in FIG. Is set to be twice the width dimension e of the second cutting inclined surface 16, so that the position of the cutting top portion 14 can be accurately positioned at the center of the plate thickness dimension b as shown in FIG. .

  In addition, in this embodiment, although the said holder 5 was formed in the column shape, if it gives another example, as shown in FIG. 8, it will be formed in a cylindrical shape and several split grooves along the longitudinal direction will be shown. You may employ | adopt the holder 18 in which 17 was formed. The split grooves 17 formed in the holder 18 are alternately arranged at one end edge of the holder 18 and at the other end edge. The outer diameter of the holder 18 can be increased by expanding the distance. The groove 8 formed in the holder 18 has the same shape as described above.

  When such a holding tool 18 is employed, as shown in FIG. 9, a drum holding means 20 including a diameter expanding means 19 for expanding the diameter of the holding tool 18 is employed. The configuration of the drum holding means 20 will be briefly described. A holder 18 is detachably mounted on a support shaft 21 connected to a rotation driving means (not shown) via a collet 22 that can be expanded in diameter. The diameter increasing means 19 for expanding the diameter of the holder 18 through the collet 22 is provided at the tip of the support shaft 21. The diameter expanding means 19 can expand the diameter of the holder 18 by advancing and retracting the taper member 24 by rotating the pressing nut 23 and expanding the diameter of the collet 22. The holder 18 is brought into close contact with the inner peripheral surface of the drum W by expanding the diameter of the holder 18 while holding the drum W. Thereby, it is possible to prevent the holder 18 and the drum W from slipping, and to obtain a highly accurate metal ring by dramatically reducing the variation in the width dimension of each metal ring cut from the drum W. .

Explanatory drawing which shows the apparatus of one Embodiment of this invention. Explanatory sectional drawing which shows a blade tool and a groove part. Explanatory drawing which shows the cutting process of the drum in this embodiment. Explanatory sectional drawing which expands and shows a part of drum at the time of a cutting | disconnection. Explanatory drawing which shows a part of cutting process of a drum. Explanatory sectional drawing which shows the cutting edge shape of the conventional drum for a comparison. Explanatory sectional drawing which shows the cutting edge shape formed in the drum by this embodiment. Explanatory drawing which shows another holder. Explanatory sectional drawing which shows the apparatus form at the time of employ | adopting the holder of FIG.

Explanation of symbols

  W ... drum, Y ... metal ring, 5 ... holding tool, 7 ... pressing blade, 8 ... groove, 9 ... inner wall, 10 ... curved surface, 11 ... deepest part, 11a ... flat part.

Claims (3)

A drum formed in a cylindrical shape by a thin metal plate is held by being extrapolated to a cylindrical holder that can be driven to rotate, and one end of the drum is fixed to the holder and rotated together with the holder. A cutting method of a thin metal plate drum in which a pressing blade is pressed against the outer peripheral surface of the drum every predetermined width from the non-fixed side of the other end of the drum and the drum is cut in the circumferential direction to form an endless belt-shaped metal ring. There,
The pressing blade tool has a blade angle in the range of 50 to 90 °, and an annular groove formed on the outer peripheral surface of the holding tool at a predetermined interval corresponding to the cutting position of the pressing blade tool. The groove is formed in a V-shape in cross section, the interval between the upper edges of the inner walls facing each other is 15 to 30 times the plate thickness of the drum, and the center of the groove The depth of the deepest part located in the portion is 1 to 3 times the plate thickness of the drum, and both inner walls of the groove have a radius of curvature of 15 to 50 times the plate thickness of the drum. And when having a curved surface protruding into the groove,
The position of the tip of the press cutting blade when cutting into the groove through the drum is a distance of 1/3 of the thickness of the drum from the center of the distance between the upper edges of the inner walls facing each other of the groove. A method for cutting a metal thin plate drum, characterized in that it is close to the non-fixed side of the drum within the range of.   2. The cutting of a metal thin plate drum according to claim 1, wherein the groove portion of the holder includes a flat portion formed flat so that the deepest portion has a constant depth between both inner side walls. Method.   When cutting the drum, the position of the tip of the pressing blade when the pressing blade is moved deepest into the groove is 0.2 mm, which is the thickness of the drum from the deepest portion of the groove. 3. The method for cutting a metal thin plate drum according to claim 1 or 2, wherein a position having a distance of -0.4 times exists.

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