JP5513923B2 - Metal ring manufacturing method - Google Patents

Description

  The present invention relates to a metal ring manufacturing method in which a metal cylindrical workpiece is cut under the action of laser light to form a plurality of metal rings.

  As a power transmission belt employed in a continuously variable transmission of an automobile, a laminated ring in which a plurality of metal rings are laminated is used. For example, as described in Patent Document 1, the metal ring that constitutes this type of laminated ring first welds both end edges of a rectangular metal thin plate to form a cylindrical drum (cylindrical workpiece). Next, the drum is manufactured by cutting the drum into a circular shape with a predetermined width. In some cases, after the welding, a solution treatment is performed for the purpose of improving the internal quality of the drum.

  Here, as a cutting means for cutting the drum, conventionally, cutters such as a grindstone and a cutting tool have been mainly employed. On the other hand, as shown in Patent Documents 2 and 3, an attempt to employ laser light is used. Has been made.

JP 2005-297074 A Japanese Patent Publication No. 63-53912 Japanese Utility Model Publication No.59-62879

  As described above, when both ends of the metal thin plate are welded, the obtained cylindrical workpiece may be distorted by the heat of welding. As is well known, the range that can be cut by the laser beam is limited. For this reason, when the distortion is large, the distance (thickness) from the inner wall to the outer wall of the cylindrical workpiece is within the focal depth of the laser beam. Difficult to do. As a result, a portion that cannot be cut is generated. As described above, a solution heat treatment may be applied to the drum after welding, but in this case, the distortion is increased and becomes larger.

  Further, if cutting is performed without correcting the distortion, the distortion remains in the metal ring. That is, it is not easy to obtain a metal ring that does not include a large strain.

  The present invention has been made to solve the above-described problems, and it is possible to correct a cylindrical workpiece into a substantially circular shape. For this reason, the cylindrical workpiece can be easily cut, and a metal that does not include distortion. An object of the present invention is to provide a metal ring manufacturing method capable of easily obtaining a ring.

To achieve the above object, the present invention provides a metal ring manufacturing method for forming a plurality of metal rings by cutting a metal cylindrical workpiece with a laser beam irradiated from a laser beam irradiation means. There,
Passing the side wall of the holding member functioning as a cooling metal for cooling the cylindrical workpiece through the through hole of the cylindrical workpiece;
Displacing the side wall of the holding member in a direction approaching the inner wall of the through-hole of the cylindrical workpiece and pressing the inner wall to correct the cylindrical workpiece into a substantially circular shape;
The side wall of the holding member is displaced in a direction away from the inner wall of the through hole of the cylindrical workpiece, and the side wall of the holding member and the inner wall of the through hole of the cylindrical workpiece are Forming a clearance therebetween,
Cutting the cylindrical workpiece that has been corrected to a substantially perfect circle shape with a laser beam while supplying a cooling medium to the clearance ; and
It is characterized by having. The “substantially perfect circle shape” in the present invention includes a shape in a range that does not hinder cutting with a laser beam.

  That is, in the present invention, the side wall of the holding member is displaced so as to approach the inner wall of the through hole of the cylindrical workpiece (in other words, the diameter of the holding member is increased). After correction so that the cross-sectional shape is a substantially perfect circle, cutting with a laser beam is performed. Since the corrected cylindrical workpiece does not have a large strain that is difficult to cut with a laser beam, the distance (thickness) from the inner wall to the outer wall of the cylindrical workpiece is within the focal depth of the laser beam. It is easy to do. Therefore, since the cylindrical workpiece can be easily cut, it is easy to produce a metal ring.

  Moreover, since the cylindrical workpiece is straightened, it is possible to obtain a metal ring that does not include a large distortion.

  And since the side wall of a holding member functions as a cooling metal, a cylindrical workpiece | work can be cooled efficiently. That is, the portion irradiated with the laser light is heated by the laser light, while the other portions are prevented from increasing in temperature due to heat conduction. Therefore, it is avoided that parts other than the part to be cut are melted. For this reason, it is possible to remarkably reduce the amount of molten metal generated and hence the amount of dross generated.

  In addition, since the cylindrical workpiece is contracted by this cooling, the distortion generated in the cylindrical workpiece is further corrected.

  When cutting the cylindrical workpiece with a laser beam, it is preferable to rotate the cylindrical workpiece by setting the peripheral speed of the cylindrical workpiece to 30 to 200 m / min. When the peripheral speed is within this range, sufficient energy is given to cut the cylindrical workpiece. That is, the cylindrical workpiece can be easily cut. In addition, since the amount of molten metal generated per unit time is reduced, the amount of dross generated is also reduced.

  In addition, a cylindrical workpiece | work can be produced by welding the both ends of a square-shaped metal plate, for example, and making it cylindrical shape. This production is performed prior to the holding on the holding member.

  Furthermore, it is preferable to provide a suction means for sucking a cooling medium leaking from the cut portion when the cylindrical workpiece is cut. By performing suction, it becomes easier to remove the cooling medium, and thus the molten metal or dross contained in the cooling medium, from the cut portion.

  In this case, it is preferable that a transport medium discharge unit is further provided and the transport medium is discharged from the transport medium discharge unit so that the cooling medium leaking from the cut portion is directed toward the suction unit. Thereby, it becomes possible to more efficiently remove the cooling medium and the molten metal or dross contained in the cooling medium from the cut portion.

  And it is preferable to set a laser beam irradiation means so that a cylindrical workpiece | work may be cut | disconnected from the supply downstream of a cooling medium toward the supply upstream.

  When the cylindrical workpiece is cut from the supply upstream side of the cooling medium, all of the cooling medium flowing in the circumferential passage leaks from this cutting point, and for this reason, the cooling medium at the next cutting point (that is, the supply downstream side) However, there is a concern that it is not easy to remove molten metal or dross as a result of no leakage as described above. On the other hand, when the cylindrical workpiece is cut from the supply downstream side of the cooling medium, the cooling medium must be present at the next cutting point (that is, the supply upstream side) even if the cooling medium leaks from the cutting point. Because it has reached, the above leakage occurs. Therefore, it is possible to easily remove the molten metal or dross at the next cutting location.

  In the above, as a suitable example of a metal ring, the power transmission belt which comprises the continuously variable transmission of a motor vehicle can be mentioned.

  According to the present invention, even when welding or the like is performed when producing a cylindrical workpiece, even if the cylindrical workpiece has a large strain that is difficult to cut with a laser beam, the cylindrical workpiece The diameter of the holding member holding the workpiece is increased, whereby the cylindrical workpiece is corrected to a substantially perfect circle to remove distortion. For this reason, since the thickness of the cylindrical workpiece is within the focal depth of the laser beam, the cylindrical workpiece can be easily cut during the subsequent laser processing.

  Moreover, it is also easy to obtain a substantially circular metal ring that does not include large distortion.

It is a partial cross section top view of the cylindrical workpiece cutting device for enforcing the manufacturing method of the metal ring concerning an embodiment of the invention. It is a principal part cross-section side view of the cylindrical workpiece cutting device shown in FIG. It is a whole schematic perspective view of a holding member. It is the whole schematic perspective view of the member for a press inserted in the inside of the said holding member. It is a front view of the cylindrical workpiece cutting device shown in FIG. It is a principal part cross-sectional side view which shows the state which the member for pressing and the holding member expanded from FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a metal ring manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a cylindrical workpiece cutting device for carrying out the method.

  FIG. 1 is a partial cross-sectional plan view of a cylindrical workpiece cutting device 10 for carrying out the metal ring manufacturing method according to the present embodiment, and FIG. 2 is a cross-sectional side view of the main part. The cylindrical workpiece cutting device 10 is held by the holding member 16, a motor 14 for rotating the spindle 12, a holding member 16 connected to the spindle 12 and rotating following the spindle 12. And a machining head 18 (see FIG. 2) as laser light irradiation means for irradiating a predetermined position of the cylindrical workpiece W with the laser light L.

  The cylindrical workpiece cutting device 10 has a base (not shown), and the first base 20 and the second base 22 shown in FIG. 1 are installed on the base. The first base 20 supports the motor 14, while the second base 22 is provided with a spindle support member 24 into which the spindle 12 is inserted. Note that a bearing 26 is interposed between the spindle support member 24 and the spindle 12, so that the spindle 12 is rotatably supported by the spindle support member 24.

  A first pulley 30 is fitted on the rotating shaft 28 of the motor 14. On the other hand, a second pulley 32 is fitted on one end of the spindle 12, and a timing belt 34 is stretched around the first pulley 30 and the second pulley 32. Accordingly, the spindle 12 starts rotating under the action of the motor 14 as will be described later.

  The spindle 12 is formed as a hollow body. That is, the inner hole 36 extends along the longitudinal direction inside the spindle 12.

  The inner hole 36 is opened at both end surfaces of the spindle 12 in the longitudinal direction, and the socket portion 40 of the pipe joint socket 38 is inserted into one of the inner holes 36. An air supply pipe (not shown) connected to the main body 41 of the pipe joint socket 38 via a pipe joint 42 is connected to a compressed air supply source that supplies compressed air as a cooling medium. That is, the compressed air that has been supplied from the compressed air supply source and passed through the air supply pipe and the pipe joint 42 flows through the inner hole 36. As can be understood from this, the inner hole 36 functions as a flow path for compressed air.

  The socket part 40 having a truncated cone shape in the pipe joint socket 38 is rotatable with respect to the main body.

  As shown in FIG. 2, the holding member 16 is connected to the spindle 12 via a first connecting member 44 and a second connecting member 46. Specifically, a step 48 is formed at one end of the spindle 12, and the columnar protrusion 50 of the first connecting member 44 is inserted into the step 48, and one of the first connecting members 44 is inserted. The first connecting bolt 52 inserted from the end face is screwed into the end of the spindle 12.

  Then, the second connection bolt 54 inserted from one end surface of the second connection member 46 is screwed into the end portion of the first connection member 44. The second connecting bolt 54 is located on the inner peripheral side of the first connecting bolt 52.

  An annular insertion port 56 is formed at one end of the second connecting member 46. On the other hand, as shown in FIGS. 2 and 3, a small-diameter portion 58 having a smaller diameter than other portions is formed at one end of the holding member 16, and the small-diameter portion 58 is inserted into the insertion port 56. Is done. The small-diameter portion 58 is embedded with a connecting pin 60 that extends toward the bottom of the insertion port 56. By fitting the connecting pin 60 into a fitting hole 62 formed in the bottom of the insertion port 56, the second connecting member 46 and the holding member 16 are connected.

  A seal member 64 is provided on the inner wall of the insertion port 56. The seal member 64 seals the space between the second connecting member 46 and the holding member 16, thereby preventing the compressed air from leaking.

  As shown in FIG. 3, the holding member 16 includes a small-diameter portion 58, a holding portion 66 that has a larger diameter than the small-diameter portion 58 and has a substantially cylindrical shape, and a larger diameter than the holding portion 66. It is a hollow body having a damming portion 68. That is, the holding member 16 is formed with an insertion through hole 70 extending along the longitudinal direction thereof. The insertion through hole 70 communicates with communication holes 72 and 74 formed through the first connection member 44 and the second connection member 46, respectively.

  The holding member 16 is formed with a plurality of radial passages 76 extending radially from the insertion through hole 70 to the side wall (outer wall). That is, the diametrical passage 76 communicates with the insertion through hole 70.

  Each of the diametrical passages 76 extends along the longitudinal direction of the holding member 16. The diameter direction passage 76 formed so as to be cut out from the small diameter portion 58 to the middle of the damming portion 68 has a diameter direction passage formed so as to be cut out from the damming portion 68 to the middle of the small diameter portion 58. 76 are adjacent.

  On the side wall of the holding portion 66 of the holding member 16, a plurality of circumferential passages 78 extending along the circumferential direction of the side wall and communicating between the adjacent diametrical passages 76 are formed. As can be understood from FIGS. 2 and 3, the circumferential passage 78 does not reach the insertion through hole 70. That is, the circumferential direction passage 78 does not directly communicate with the insertion through hole 70 but communicates with the insertion through hole 70 only through the diameter direction passage 76.

  As shown in FIG. 2, a pressing member 80 is inserted into the holding member 16 configured as described above, and further, the first diameter changing member 82 and the second diameter changing member 80 are inserted into the pressing member 80. A diameter changing member 84 is inserted. Here, there is a predetermined clearance between the first diameter changing member 82, the communication holes 72 and 74 of the first connecting member 44 and the second connecting member 46, and the insertion through hole 70 of the holding member 16. It is formed.

  As shown in FIG. 2, the pressing member 80 is a hollow body. Then, in the pressing member 80, as shown in FIG. 4, a plurality of (four in this case) slits 86 penetrating from the inner wall toward the outer wall are formed so as to extend along the longitudinal direction. Is done. In addition, the slit 86 is arrange | positioned so that what goes to the right end from the left end in FIG. 4 and what goes to the left end from a right end may be alternated.

  By forming such a slit 86, the pressing member 80 can easily be elastically deformed.

  On the inner wall of the pressing member 80, two first cam portions 88 and 90 are formed which are tapered in diameter as they are separated from the left end and the right end (see particularly FIG. 2). The vicinity of the middle part of the inner wall of the pressing member 80 has a substantially equal diameter over a predetermined length.

  On the other hand, the first diameter changing member 82 includes a cylindrical portion 92 and a second cam portion 94 that is reduced in taper as it is inserted into the pressing member 80. It is inserted into the pressing member 80 so as to be in sliding contact with the first cam portion 88.

  The second diameter changing member 84 has a substantially frustoconical shape, and the side wall of the second diameter changing member 84 decreases in a tapered shape as it is inserted into the pressing member 80, and the cam portion is in sliding contact with the first cam portion 90. Function as. Hereinafter, this side wall is referred to as a second cam portion 96.

  The first diameter changing member 82 and the second diameter changing member 84 are formed with insertion holes 98 and 100 penetrating along the longitudinal direction, respectively. One connecting bar 102 is inserted into these insertion holes 98 and 100. Further, a coil that elastically urges the first diameter changing member 82 and the second diameter changing member 84 in a direction away from each other between the first diameter changing member 82 and the second diameter changing member 84. A spring 104 is arranged.

  A wide flange portion 106 is formed at the left end portion of the connecting bar 102 in FIG. One end surface of the flange portion 106 is seated on the accommodation step portion 108 formed at the end portion of the cylindrical portion 92 of the first diameter changing member 82.

  A disc-shaped body 110 having a diameter corresponding to the diameter of the insertion through hole 70 of the holding member 16 is inserted into the bottom surface (the right end surface in FIG. 2) of the second diameter changing member 84. The disk-shaped body 110 and the second diameter changing member 84 are connected via a third connecting bolt 112.

  A disc-shaped cover member 116 is connected to the outside of the disc-shaped body 110 (the right end in FIG. 2) via a fourth connecting bolt 114. The diameter of the cover member 116 is set larger than the diameter of the insertion through hole 70. That is, the cover member 116 is not inserted into the insertion through hole 70.

  Projecting holes 118 and 120 are formed through the disc-shaped body 110 and the cover member 116, respectively.

  The right end portion of the connecting bar 102 in FIG. 2 is exposed through the insertion hole 100 of the second diameter changing member 84, the disk-shaped body 110, and the protrusion holes 118, 120 of the cover member 116. A screw portion 122 is formed at the exposed right end portion, and two tightening nuts 124 and 126 are screwed to the screw portion 122. The diameters of the tightening nuts 124 and 126 are set smaller than the diameter of the projecting hole 120 and larger than the diameter of the projecting hole 118.

  In the above configuration, in the vicinity of the outer peripheral wall of the cylindrical workpiece W, as shown in FIG. 5, a discharge nozzle 128 that constitutes a discharge mechanism and discharges argon gas, nitrogen gas, compressed air, or the like, and a suction mechanism And the suction nozzle 130 that performs the suction action are arranged so as to face each other.

Here, as shown in FIG. 5, the processing head 18 is a line extending from the rotation center O of the holding member 16, i.e., with respect to the radius (virtual line M1) of the holding member 16, rotationally offset on the upstream side And facing the holding member 16. That is, the virtual axis M2 of the laser beam L forms an angle θ with the virtual line M1. Hereinafter, for convenience, this angle θ is referred to as an incident angle.

  Next, the metal ring manufacturing method according to the present embodiment will be described in detail in relation to the operation of the cylindrical workpiece cutting device 10 configured as described above.

  In manufacturing a metal ring for producing a power transmission belt used in a continuously variable transmission, for example, first, a rectangular metal thin plate is cut out, and the rectangular metal thin plate is bent to form both end edges. Is welded to obtain a cylindrical workpiece W which is a cylindrical body. In addition, as a metal thin plate, that whose thickness is about 0.3-0.4 mm is generally used. The metal thin plate is preferably made of maraging steel.

  When cutting the cylindrical workpiece W, first, the side wall of the holding member 16 is passed through the through hole of the cylindrical workpiece W from the small diameter portion 58 side. The cylindrical workpiece W is blocked by the blocking portion 68 of the holding member 16 and is positioned on the holding portion 66. A slight clearance is formed between the outer wall of the holding portion 66 and the inner wall of the cylindrical workpiece W.

  Thereafter, the holding member 16 is connected to the second connecting member 46 via the connecting pin 60, whereby the cylindrical work W is held by the cylindrical work cutting device 10.

  As described above, the cylindrical workpiece W may be distorted by heat during welding. Therefore, in the present embodiment, the cylindrical workpiece W is pressed by increasing the diameter of the holding member 16.

  Specifically, the tightening nuts 124 and 126 are screwed in the tightening direction. As a result, the tightening nuts 124 and 126 are displaced toward the second diameter changing member 84 side. Since the diameters of the tightening nuts 124 and 126 are larger than the diameter of the projecting hole 118, the tightening nuts 124 and 126 press the disk-shaped body 110 to change the second diameter changing member 84 into the first diameter change. Press toward the member 82 side.

  At the same time, as the tightening nuts 124 and 126 are screwed, the threaded portion 122 of the connecting bar 102 is pulled to the right in FIG. Thereby, the connection bar 102 is displaced toward the second diameter changing member 84 side.

  As described above, the flange portion 106 of the connecting bar 102 is seated on the accommodation step portion 108 of the first diameter changing member 82. Therefore, the first diameter changing member 82 is pulled by the connecting bar 102 that is displaced toward the second diameter changing member 84 side. In other words, the first diameter change member 82 follows the connecting bar 102 and is displaced toward the second diameter change member 84 side.

  That is, as shown in FIG. 6, both the first diameter changing member 82 and the second diameter changing member 84 are displaced so as to be inserted deep inside in the longitudinal direction of the pressing member 80, and at the same time, the coil spring. 104 compresses. Due to this displacement, the larger diameter portion of each of the second cam portions 94 and 96 of the first diameter changing member 82 and the second diameter changing member 84 contacts the first cam portions 88 and 90 of the pressing member 80. Get in touch. As a result, the first cam portions 88 and 90 are pressed from the second cam portions 94 and 96. The pressing force from the second cam portions 94 and 96 is directed outward in the diameter direction of the pressing member 80.

  By this pressing, the pressing member 80 is expanded in diameter. This is because the pressing member 80 is pressed in the direction toward the outside in the diametrical direction via the first cam portions 88 and 90 formed on the inner wall thereof. As described above, since the pressing member 80 is easily elastically deformed, this diameter expansion also proceeds easily.

  The expanded pressing member 80 presses the holding portion 66 of the holding member 16 substantially evenly along the direction outward in the diameter direction. As shown in FIG. 3, the holding member 16 is formed with a plurality of diametrical passages 76 and a circumferential passage 78. For this reason, the holding member 16 is also rich in elasticity. That is, the holding member 16 is easily elastically deformed by being pressed from the pressing member 80, and expands the diameter substantially uniformly.

  For example, when the cylindrical workpiece W is distorted and the inner diameter of the cylindrical workpiece W is non-uniform, the holding portion holds the portion with the smallest inner diameter in the cylindrical workpiece W during the expansion. 66 side walls abut. On the other hand, a portion having an inner diameter larger than this portion is still separated from the side wall of the holding portion 66.

  As the diameter of the holding portion 66 further increases, the portion having the smallest inner diameter is expanded. Further, the side wall of the holding portion 66 abuts on a portion where the inner diameter of the cylindrical workpiece W is slightly large.

  When the diameter of the holding portion 66 further increases, the portion having the smallest inner diameter is further expanded, and the portion having a slightly larger inner diameter is expanded. As the diameter of the holding portion 66 increases in this way, the side wall of the holding portion 66 comes into contact with the portion having the largest inner diameter in the cylindrical workpiece W.

  At this time, the portion where the inner diameter is the smallest or the portion where the inner diameter is slightly larger than the portion is expanded to the extent that the inner diameter is substantially the same as the portion where the inner diameter is the largest. That is, the cylindrical workpiece W is corrected so that its cross section has a substantially perfect circle shape.

  As described above, the cylindrical workpiece W is corrected. When the tightening nuts 124 and 126 are excessively screwed, the cover member 116 is blocked by the blocking portion 68 of the holding member 16, and the disk-shaped body 110, and thus the first diameter changing member 82 and the second Further displacement of the diameter changing member 84 is stopped. Thereby, the diameter expansion of the pressing member 80 and the holding part 66 is also stopped.

  Thereafter, the tightening nuts 124 and 126 may be screwed in the direction of loosening in the reverse manner. At this time, the coil spring 104 elastically biases both the first diameter changing member 82 and the second diameter changing member 84 in a direction away from each other. As a result, the first diameter-changing member 82 and the second diameter-changing member 84 are displaced in a direction away from the inside of the pressing member 80.

  Therefore, in each of the second cam portions 94 and 96 of the first diameter changing member 82 and the second diameter changing member 84, the small diameter portion is in contact with the first cam portions 88 and 90 of the pressing member 80. Become. For this reason, the first cam portions 88 and 90 are released from being pressed by the second cam portions 94 and 96. In other words, since there is no pressing force for expanding the pressing member 80, the pressing member 80 is reduced in diameter.

  Accordingly, the holding portion 66 of the holding member 16 is also reduced in diameter. This is because the holding member 16 is released from the pressing force of the pressing member 80.

  When the diameter of the holding portion 66 is reduced, for example, the state shown in FIG. 2, that is, the initial state before the diameter expansion may be returned, or the diameter may be returned to a slightly larger diameter than the initial state. In the following, the case where the initial state is restored will be described as an example.

  Even when the holding portion 66 of the holding member 16 and the pressing member 80 are returned to the initial state, the cylindrical workpiece W is not so elastic, and thus returns from the corrected shape to the original shape. There is nothing. That is, the corrected substantially perfect circle shape is maintained.

  Next, the motor 14 is driven. With this driving, the rotating shaft 28 of the motor 14 starts rotating. Following this rotation operation, the first pulley 30 rotates and the timing belt 34 rotates. As a result, the second pulley 32 rotates. Following this, the spindle 12 and the holding member 16 connected to the spindle 12 start rotating.

  The rotational driving force of the motor 14 is preferably set so that the rotational speed of the cylindrical workpiece W held by the holding member 16 is a peripheral speed of 30 to 200 m / min. As described above, since the bearing 26 is interposed between the spindle 12 and the spindle support member 24, the spindle support member 24 does not rotate. Further, in the pipe joint socket 38, only the socket portion 40 rotates, and the main body portion 41 does not rotate.

  At the same time, the discharge mechanism and the suction mechanism are driven, and compressed air or the like (conveyance medium) is discharged from the discharge nozzle 128, and suction through the suction nozzle 130 is started. Since the discharge nozzle 128 and the suction nozzle 130 face each other, compressed air or the like discharged from the discharge nozzle 128 circulates toward the suction nozzle 130.

  Before and after this, compressed air as a cooling medium is supplied from the compressed air supply source. The compressed air reaches the pipe joint socket 38 via the air supply pipe and the pipe joint 42 and is supplied from the socket portion 40 to the inner hole 36 of the spindle 12.

  Compressed air flows through the inner hole 36 and is used for inserting the cylindrical portion 92 of the first diameter changing member 82, the communication holes 72 and 74 of the first connecting member 44 and the second connecting member 46, and the holding member 16. It passes through the clearance between the through hole 70 and reaches the inside of the holding member 16, that is, the insertion through hole 70. Furthermore, it moves to the outer wall (side wall) side through a diametrical passage 76 (see FIG. 3) formed in the holding member 16 and communicated with the insertion through hole 70, and a part of it moves relative to the inner wall of the cylindrical workpiece W. , Contact along the longitudinal direction. Further, the remaining portion moves around the side wall of the holding portion 66 by circulating through the circumferential direction passage 78, and contacts the inner wall of the cylindrical workpiece W along the circumferential direction.

  When the holding portion 66 of the holding member 16 and the pressing member 80 are reduced in diameter from the diameter when the cylindrical workpiece W is corrected, there is a slight gap between the side wall of the holding portion 66 and the inner wall of the cylindrical workpiece W. There is clearance. Therefore, the compressed air forms an air film in this clearance. On the other hand, when the compressed air reaches the side wall of the holding member 16 in this manner, the side wall functions as a cooling metal having excellent cooling efficiency.

  Even if the diameters of the holding portion 66 and the pressing member 80 are the same as the diameter when the cylindrical workpiece W is corrected, the compressed air is still between the side wall of the holding portion 66 and the inner wall of the cylindrical workpiece W. Enter to form an air film.

  Next, the laser beam L is irradiated from the processing head 18 toward the cylindrical workpiece W. In the present embodiment, the laser beam L is first irradiated near the right end in FIG. 2 of the cylindrical workpiece W, in other words, the most downstream side to which compressed air is supplied. At this time, the portion irradiated with the laser light L and the position of the circulation direction passage 78 substantially coincide with each other.

  The part of the cylindrical workpiece W where the laser light L is incident is melted due to an increase in temperature, and is separated from the cylindrical workpiece W. That is, it is cut as a metal ring. At the time of melting, sublimation metal gas is generated from the cylindrical workpiece W as the metal (for example, maraging steel) is sublimated. Of course, even if the material of the cylindrical workpiece W is a metal other than maraging steel, for example, stainless steel or other metals, sublimation metal gas is generated as described above.

  In the case of this cutting | disconnection, sufficient energy for the cylindrical workpiece | work W to cut | disconnect is provided as the rotational speed of the cylindrical workpiece | work W is 30-200 m / min. That is, the cylindrical workpiece W can be easily cut. Further, when the rotational speed is within this range, the amount of molten metal generated per unit time is small. The reason for this is as follows.

  Since the cylindrical workpiece W is rotating, the laser light L is incident on the same part of the cylindrical workpiece W intermittently. This is because the portion where the laser beam L is incident is separated from the laser beam L as the cylindrical workpiece W rotates.

  Here, the energy density of the general laser beam L is high at the center of the spot width and low at the end. That is, the laser light L has a distribution in energy density. For this reason, in the cylindrical workpiece W, the portion where the center of the spot width is incident is likely to be sublimated, while the portion where the end portion is incident is less likely to be sublimated.

  When the rotation speed is within the above range, the portion where the center of the spot width (high energy density) is incident is instantly sublimated to become a sublimated metal gas. On the other hand, although the temperature rises at the site where the end (low energy density) is incident, it is generally below the melting point. The part is separated from the laser beam L with the rotation of the cylindrical workpiece W, and thereby the temperature is prevented from rising, so it is difficult for the temperature of the part to exceed the melting point. For this reason, it becomes difficult to generate molten metal. For this reason, generation | occurrence | production of dross is avoided.

  This portion is sublimated when the center of the spot width of the laser beam L is incident when the rotational speed of the cylindrical workpiece W reaches the second rotation or later. Thereby, as above-mentioned, the cylindrical workpiece | work W is cut | disconnected and a metal ring is obtained.

  In addition, since almost all of the generated sublimation metal gas can be sucked by the suction nozzle 130, the sublimation metal gas can be prevented from adhering to the cylindrical workpiece W, and hence dross.

  Furthermore, the side wall of the holding member 16 functions as an efficient cooling metal by supplying compressed air. For this reason, it is avoided that the temperature of the part other than the part irradiated with the laser beam L in the cylindrical workpiece W is increased, and eventually the part is avoided from melting and dross is generated in the part. Is avoided.

  Moreover, in the present embodiment, an air film is formed between the side wall of the holding member 16 and the inner wall of the cylindrical workpiece W. Therefore, even if molten metal or dross is generated, the molten metal or dross is absorbed by the air film.

  Here, when the molten metal generated during the cutting solidifies, a layered line (drag line) remains on the cylindrical workpiece W along the laser beam L. In the present embodiment, as shown in FIG. Thus, the processing head 18 is disposed at a position offset from the rotation center line of the holding member 16. Therefore, the laser beam L is incident on the cylindrical workpiece W with an incident angle θ.

  In such processing, the drag line is formed so as to go straight from the outer wall side of the cylindrical workpiece to the inner wall side, that is, along the thickness direction. In this case, dross hardly adheres.

  That is, by arranging the machining head 18 at a position where its axis is offset from the rotation center line of the holding member 16 and causing the laser light L to enter the cylindrical workpiece W at an incident angle θ, the dross is attached. This can be avoided further.

  When the cylindrical workpiece W is cut, the irradiated portion of the laser light L and the position of the circumferential passage 78 are substantially coincident with each other, so that the circumferential passage 78 is exposed and the air film leaks to the outside. Thereafter, the air film is scattered by centrifugal force. This is because the holding member 16 is rotating.

  This air film contains molten metal or dross as described above. That is, even if molten metal or dross is generated, these molten metal or dross is efficiently removed from the cut portion.

In this case, compressed air or the like is discharged from the discharge nozzle 128 and suction is performed through the suction nozzle 130. Since the compressed air or the like flows toward the suction nozzle 130, the air film is conveyed to the compressed air or the like and heads toward the suction nozzle 130. As can be understood from this, the compressed air or the like functions as a transport medium that transports the air film toward the suction nozzle 130, thereby efficiently removing the air film.

  Of course, sublimation metal gas, molten metal or the like generated at the cutting position when cutting with the laser beam L is also conveyed to the suction nozzle 130 by compressed air or the like. For this reason, a cutting location is kept clean.

  After one metal ring is obtained in this way, the machining head 18 moves and irradiates another part of the cylindrical workpiece W with the laser light L as shown in FIG. Also in this case, the machining head 18 moves to a position corresponding to the position of the circumferential passage 78, and thereafter the cylindrical workpiece W is cut in the same manner as described above.

  When the cylindrical workpiece W is cut from the left end side close to the second connecting member 46, that is, from the upstream side to which the compressed air is supplied, all the compressed air supplied to the inside of the holding member 16 leaks from the cut portion. For this reason, there is a concern that an air film is not formed between the side wall of the holding portion 66 and the cylindrical workpiece W. However, in the present embodiment, since the cylindrical workpiece W is cut from the downstream side to which the compressed air is supplied, the compressed air supplied to the inside of the holding member 16 is separated from the side wall of the holding portion 66, It reaches between the inner wall of the cylindrical workpiece W that has not been cut yet. For this reason, since the said air film is formed continuously, a molten metal thru | or dross can be easily removed in a cutting location.

  In the above-described embodiment, the case where compressed air is used as the cooling medium is described as an example. However, other gases or liquids may be used. In this case, a liquid film is formed instead of the air film described above, and this liquid film also functions to efficiently remove the molten metal or dross from the cut portion. As the liquid, water is suitable because of its good cooling efficiency and low cost.

  The transport medium ejected from the ejection nozzle 128 may also be a liquid such as water. In this case, it is possible to cool the cut portion more efficiently and to obtain an advantage that the cut portion can be kept clean. In the case of liquid, it goes without saying that the discharge nozzle 128 and the suction nozzle 130 are set to positions that do not hinder the irradiation of the laser light L.

  Further, it is not particularly necessary that the irradiation position of the laser light L corresponds to the position of the circulation direction passage 78. This is because even if the irradiation position of the laser beam L and the position of the circumferential passage 78 do not coincide with each other, the leakage of the liquid film or the air film is not particularly disturbed.

  Furthermore, it goes without saying that a metal ring other than the power transmission belt employed in the continuously variable transmission of the automobile may be produced.

DESCRIPTION OF SYMBOLS 10 ... Cylindrical workpiece cutting device 12 ... Spindle 14 ... Motor 16 ... Holding member 18 ... Processing head 58 ... Small diameter part 66 ... Holding part 68 ... Damping part 70 ... Insertion through-hole 76 ... Diameter direction channel | path 78 ... Circumferential direction channel | path 80 ... Pressing member 82 ... First diameter changing member 84 ... Second diameter changing member 86 ... Slit 88, 90 ... First cam portion 94, 96 ... Second cam portion 102 ... Connecting bar 104 ... Coil spring 110 ... Disc-shaped body 116 ... Cover member 124, 126 ... Tightening nut 128 ... Discharge nozzle 130 ... Suction nozzle L ... Laser light W ... Cylindrical workpiece

Claims (8)

A metal ring manufacturing method for forming a plurality of metal rings by cutting a metal cylindrical workpiece with a laser beam irradiated from a laser beam irradiation means,
Passing the side wall of the holding member functioning as a cooling metal for cooling the cylindrical workpiece through the through hole of the cylindrical workpiece;
Displacing the side wall of the holding member in a direction approaching the inner wall of the through-hole of the cylindrical workpiece and pressing the inner wall to correct the cylindrical workpiece into a substantially circular shape;
The side wall of the holding member is displaced in a direction away from the inner wall of the through hole of the cylindrical workpiece, and the side wall of the holding member and the inner wall of the through hole of the cylindrical workpiece are Forming a clearance therebetween,
Cutting the cylindrical workpiece that has been corrected to a substantially perfect circle shape with a laser beam while supplying a cooling medium to the clearance ; and
A method for producing a metal ring, comprising: 2. The method of manufacturing a metal ring according to claim 1, wherein the axis of the laser beam is incident from a position offset from a rotation center line of the holding member. The manufacturing method according to claim 1 or 2, wherein, the production method of the metal ring, characterized in that the cylindrical workpiece is rotation at a peripheral speed of 30 to 200 m / min in cutting the cylindrical workpiece by a laser beam . The manufacturing method according to any one of claims 1 to 3, wherein the cylindrical workpiece is formed by welding both end edges of a rectangular metal plate to form a cylindrical shape. Production method. The method of manufacture according to any one of claims 1-4, method for producing a metal ring, characterized in that the suction by the suction means the cooling medium leaking from the cut portion at the time of cutting the cylindrical workpiece . 6. The method of manufacturing a metal ring according to claim 5 , wherein the cooling medium leaking from the cut portion is transported toward the suction means by the transport medium discharged from the transport medium discharge means. The method of manufacture according to any one of claims 1 to 6 the laser beam irradiation means, the cylindrical workpiece toward the feed upstream from the feed downstream of the cooling medium displaces to be cleaved A metal ring manufacturing method characterized by the above. The method of manufacture according to any one of claims 1 to 7, wherein the metal ring, the production method of the metal ring, characterized in that to obtain a power transmission belt which constitutes the continuously variable transmission of an automobile.

Images